Full text of "Genesis: Generalized model for simulating shoreline change, report 1, technical reference"

See other formats

oy ee a Re CERCLT-G

TECHNICAL REPORT CERC-89-19 Mhe / PEF

GENESIS: GENERALIZED MODEL FOR
SIMULATING SHORELINE CHANGE

Report 1
TECHNICAL REFERENCE

US Army Corps
of Engineers

by
Hans Hanson

Department of Water Resources Engineering
Lund Institute of Science and Technology
University of Lund
Box 118, Lund, Sweden S-221 00

and
Nicholas C. Kraus

Coastal Engineering Research Center

DEPARTMENT OF THE ARMY
Waterways Experiment Station, Corps of Engineers
3909 Halls Ferry Road, Vicksburg, Mississippi 39180-6199

RARY
ie ole Gceanoerae™
ynstitution

December 1989
Report 1 of a Series

Approved For Public Release; Distribution Unlimited

Prepared for DEPARTMENT OF THE ARMY
US Army Corps of Engineers
Washington, DC 20314-1000
Under Surf Zone Sediment Transport Processes
Work Unit 34321 and Shoreline and Beach
Topography Response Modeling Work Unit 32530

Destroy this report when no longer needed. Do not return
it to the originator.

The findings in this report are not to be construed as an official
Department of the Army position unless so designated
by other authorized documents.

The contents of this report are not to be used for

advertising, publication, or promotional purposes.

Citation of trade names does not constitute an

official endorsement or approval of the use of
such commercial products.

Unclassified
SECURITY CLASSIFICATION OF THIS PAGE

Form Approved

REPORT DOCUMENTATION PAGE OMB No. 0704-0188

Ja. REPORT SECURITY CLASSIFICATION 1b. RESTRICTIVE MARKINGS
Unclassified

2a. SECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION / AVAILABILITY OF REPORT
Approved for public release; distribution
2b. DECLASSIFICATION / DOWNGRADING SCHEDULE unlimited.

4. PERFORMING ORGANIZATION REPORT NUMBER(S) 5. MONITORING ORGANIZATION REPORT NUMBER(S)
Technical Report CERC-89-19

6a. NAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION
(If applicable)
See reverse.

6c. ADDRESS (City, State, and ZIP Code) 7b. ADDRESS (City, State, and ZIP Code)

See reverse.

8a. NAME OF FUNDING/ SPONSORING 8b. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER
ORGANIZATION (If applicable)

US Army Corps of Engineers
8c. ADDRESS (City, State, and ZIP Code) 10. SOURCE OF FUNDING NUMBERS

PROGRAM PROJECT TASK
Washington, DC 20314-1000 ELEMENT NO. NO. NO.

11. TITLE (Include Security Classification)

GENESIS: Generalized Model for Simulating Shoreline Change; Report 1, Technical Reference

12. PERSONAL AUTHOR(S)
Hanson, Hans; Kraus, Nicholas C.

13a. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT (Year, Month, Day) 415. PAGE COUNT
Report 1 of a series FROM [Olas December 1989 oul
16. SUPPLEMENTARY NOTATION

Available from National Technical Information Service, 5285 Port Royal Road, Springfield,
VA 22161.

17. COSATI CODES 18. SUBJECT TERMS (Continue on reverse if necessary and identify by block number)
SUB-GROUP__| Beach change Shoreline change
2S Ra eee) Longshore sand transport Shoreline change model

Shore protection
19, ABSTRACT (Continue on reverse if necessary and identify by block number)

This report documents a numerical modeling system named GENESIS, which is designed
to simulate long-term shoreline change at coastal engineering projects as produced by
spatial and temporal changes in longshore sand transport. The name "GENESIS" is an
acronym that stands for GENEralized Model for SImulating Shoreline Change, Typical
longshore extents and time periods of modeled projects can be in the ranges of 1 to
100 km and 1 to 100 months, respectively, and almost arbitrary numbers and combinations
of groins, detached breakwaters, seawalls, jetties, and beach fills can be represented.
GENESIS contains what is believed to be a reasonable balance between present capabilities
to efficiently and accurately calculate coastal sediment processes from engineering data
and the limitations in both the data and knowledge of sediment transport and beach
change.

20. DISTRIBUTION / AVAILABILITY OF ABSTRACT 21. ABSTRACT SECURITY CLASSIFICATION i

Gq] UNCLASSIFIED/UNLIMITED [1] SAME AS RPT. C) oTic USERS Unclassified

22a. NAME OF RESPONSIBLE INDIVIDUAL 22b. TELEPHONE (Include Area Code) | 22c. OFFICE SYMBOL

DD Form 1473, JUN 86 Previous editions are obsolete. SECURITY CLASSIFICATION OF THIS PAGE

ncelassifie
o 0

S05 CGALTeo7 4

Unclassified
ED
SECURITY CLASSIFICATION OF THIS PAGE

6. NAME AND ADDRESS OF PERFORMING ORGANIZATION (Continued)

University of Lund

Lund Institute of Science and Technology
Department of Water Resources Engineering
Box 118, Lund, Sweden S-221 00

USAEWES, Coastal Engineering Research Center
3909 Halls Ferry Road
Vicksburg, MS 39180-6199

19. ABSTRACT (Continued).

The modeling system is operated through a structured and user-friendly interface so
that the operator need not become familiar with detailed aspects of the computer code,
This report serves as a technical reference to Version 2 of GENESIS and is also designed
to be an operator's manual by providing instructions for using the interface. The
methodology for application of the modeling system is described from the perspective of
the needs of both engineers and planners who deal with evaluation of shore-protection
projects. Capabilities and limitations of the modeling system are presented in the text
and through examples, and the report concludes with a fully documented case study
involving application of the modeling system and exercise of many of its features.

Unclassified

ae
SECURITY CLASSIFICATION OF THIS PAGE

PREFACE

The work described herein was authorized as a part of the Civil Works
Research and Development Program by Headquarters, US Army Corps of Engineers
(HQUSACE). Work was performed under the Surf Zone Sediment Transport Proces-
ses Work Unit 34321 and the Shoreline and Beach Topography Response Modeling
Work Unit 32592, which are part of the Shore Protection and Restoration
Program at the Coastal Engineering Research Center (CERC) at the US Army
Engineer Waterways Experiment Station (WES). Messrs. John H. Lockhart, Jr.,
and John G. Housley were HQUSACE Technical Monitors.

This report was written and the shoreline change modeling system
improved over the period from 1 May 1988 through 30 September 1989 by Dr. Hans
Hanson, Associate Professor, Department of Water Resources Engineering (DWRE),
Lund Institute of Science and Technology, University of Lund (UL), Sweden, and
Dr. Nicholas C. Kraus, Senior Scientist, Research Division (RD), CERC. Work
performed at the UL was under the administrative supervision of Professor
Dr. Gunnar Lindh, Head, DWRE. The CERC portion of the study was under the
general administrative supervision of Dr. James R. Houston, Chief, CERC;

Mr. Charles C. Calhoun, Jr., Assistant Chief, CERC; Dr. Charles L. Vincent,
Program Manager, Shore Protection and Restoration Program, CERC; and Mr. H.
Lee Butler, Chief, RD, CERC. The framework of this report was developed and a
detailed draft outline written while Dr. Kraus was in residence at DWRE over
the period May-June 1988.

Dr. Kraus was Principal Investigator of Work Unit 34321 during the
conceptual and model development phase of this study; Ms. Kathryn J.
Gingerich, Coastal Processes Branch (CPB), RD, was Principal Investigator
during preparation of the working draft of this report, which was used ina
September 1989 workshop. Final revision and publication of this report were
made under the Shoreline and Beach Topography Response Modeling Work Unit
32592. Mr. Mark B. Gravens, CPB, was Principal Investigator of Work Unit
32592, under the direct supervision of Mr. Bruce A. Ebersole, Chief, CPB.

Ms. Gingerich, Mr. Gravens, and Ms. Julie Dean Rosati, CPB, provided
valuable reviews of the report. Ms. Joan Pope, Chief, Coastal Structures and

Evaluation Branch, Engineering Development Division, reviewed the case study

and made many clarifications. Ms. Gingerich made substantial editorial
contributions in preparation of the draft report used in the workshop and
assisted in many details involved with production of this report. Ms. Carolyn
Dickson and Mr. Fulton Carson, CPB, prepared most of the computer-generated
figures. Ms. Carrie E. Williford, RD, assisted in editing and formatting
preliminary drafts of this report. Participants of the September 1989
workshop are acknowledged for suggestions on improvement of this report.
This report was edited by Ms. Lee Byrne, Information Technology Laboratory,
WES.

COL Larry B. Fulton, EN, was Commander and Director of WES during final
report preparation and publication. Dr. Robert W. Whalin was Technical

Director.

CONTENTS

PREFACE .

LIST OF TABLES

LIST OF FIGURES

CONVERSION FACTORS, NON-SI TO SI (METRIC) UNITS OF MEASUREMENT
PART I: INTRODUCTION .

GENESIS ;

Mode of Tmceraecion wich GENESIS
Cautions ;

Scope of This Repore!

PART II: OVERVIEW OF BEACH CHANGE MODELS .

Need for Models of Shoreline Change
Shoreline Change Model and Capabilities
Duration and Extent of Simulation .
Comparison of Beach Change Models
Conclusions

PART III: SHORELINE CHANGE MODELING AS A TOOL IN THE PLANNING PROCESS

Elements of the Planning Process
Role of Shoreline eee ee d
Conclusions fio Fre fore

PART IV: PROJECT EVALUATION AND USES OF GENESIS

Scoping Mode and ar ae Mode
Input Data

Boundary Gondittens 5
Variability in Coastal Processes
Calibration and Verification
Sensitivity Testing .
Interpretation of Resuice

PART V: THEORY OF SHORELINE RESPONSE MODELING AND GENESIS

Basic Assumptions of Shoreline Change Modeling
Governing Equation for Shoreline Change

Sand Transport Rates

Empirical Parameters

Wave Calculation

Internal Wave Teemerocmaeion! Model | Ses
External Wave Transformation Model: RCPWAVE

CONTENTS (Continued)

Page

Limiting: Deepwater WaverSteepness, . = .)9. 0s eee cl eee) © lease eine 76

Wave Enerpy Wind owsiy ster gies leis be bitte: denies iylieng ot cues ee gisug tense ee 77
Numerical Solution Scheme . . . Sh yen ata ea a neeaee 81

Grid System and Finite Dieference Solution! Scheme > lek: ae 84
Lateral Boundary Conditions and Constraints ............ 86

Beachy rise ae i TAs see ups Ese los Acoli x aibieioy SAD cole ecg at (oe trey ae a i 90
Longshore Transport Rate: Practical Considerations ........ 91

PART OVE a SERUG TURE GOS GENESIS iirc cy een netces Ue ser rote op me ctrr eg cys eee 97
Preparation ito Run ‘CENESTS) 030 sii. a i vei ad os sce ee ee, 97

a Goh ob ce) Said -\- oC Lote ir a MAI ES sy og dOW

SUNG Se ne Cured Adhd. Sein ECOL ON RAR ome OCCU aR GniGL Tone Ge cto. ig dO

3) 10) UD oavea cow nesy, OREN: qi aan aoe pT ude to NO MA Geer aI Sabo oo 6 LOS}

5 (0) 1a frees aoe Ae oo Cin aN OM eesc Toe! foil ie o.oo dLah

SO Cia eet ames Skac aa ce COLMAR Sl eae A RRC UENO Se Ss gg, IL2S

DEPTH 5 cou a), ec ee ce, We) Gey ee, omy eet Tees gmegihiey coe 18 Che Sen ey oe em AG

WAVES Pies) = eR ate arall erie enyRschlesl gioteanedl bes arepacuh Realises ere lanitel an titel ne flee sae ae a LW)
Output ales: SERS ec Pea oy Len ook os on ane Tomer! Gg dle)

Error and Warning Mescaeee! Hepes eel oO RAO Tol ToMen tore ioc o'-5: LG

PART VII: REPRESENTATION OF STRUCTURES AND BEACH FILL ......... 138
Lypes of Structures ‘and Their EEfects 29) e512 tes ce ee ee

Grid) CellsxandyNumbers of Structures! 92 ti. s . EN eeeee, oe SS
Representation of Structures 7) 3 = eae faa a a sl ee CS 9)
Complex) Groin, Configurations) (2) em) ieee eee Mae en eS

RY OER EB een te es are nM RH UNM rane ton Gmc Tes ne Toned le esr lest ano). a 5. AS

Beach, Biliis, 2). 30. Poke mes Toei’ oo. AG
Time-Varying Structure iContiearations Bouton yea at Sociale ev canl ach asta Nae aS

PART VITE: CASE STUDY OF LAKEVIEW PARK, LORAIN, OHIO). - 5 2 3.0. 2 leg
Backgrounds oi. yc See Pee eee ek eels na ace Sen cpl elias pci we eae RCE
Existing |Project) 2.2... lj ye, ee ee els topos oe OSE Gini Oa pea ele 2
Assembly of Data ... renters efor ce home ich ror then pee gaeta sch as 6G. fo! LSD)
Calibration and Verification’ Pe ao on pate Re Paar or et onal noes on GQ - AlOO
Sensitivity, and) Variability Tests) | 20171). 0 enn ie tel ee LOD
Alternative: Structure, Configurations 1) cae lesen esc cab ei te ae LS
Five-Year Simulation, 0 iio line ac gb te phe es oe a) ee noe ep)
Summary, and Discussion is ise. cman Say eupealiohs (ll g Chnenl es cee mmElay6
REFERENCES Gigiec is, sess © (ol peal UM ee TOnEy) RNS eect eee derek Ue iy ae 79)
APPENDIX A: ‘REVIEW OF RELATED GENESIS (STUDIES .. Gane; <vegtunes meee: Al
APPENDIX -B:, ‘BEANK-UNPUT, PEGES | S80 sa atic von Su cig eye) Se oe ee Bl
NW ec OS TAT omit, Koll Gol Rone con fore "oulaG! Vol euua Woy ton cor Bl

CONTENTS (Continued )

SHORL .
SEAWL .
DEPTH .
WAVES

APPENDIX C: ERROR AND WARNING MESSAGES AND RECOVERY PROCEDURES

Error Messages
Warninp Messages ii (Un at rin) os ajers
Error Messages Issued by the Computer

APPENDIX D: INPUT AND OUTPUT FILES FOR CASE STUDY

START Files
SHORL Files
SEAWL File
WAVES File
OUTPT Files

APPENDIX E: NOTATION .

Mathematical Notation .
Program Variable Names

APPENDIX F: INDEX

NDUFWNE

WOMANHUNKFWNHE

LIST OF TABLES

Major Capabilities and Limitations of GENESIS Version 2
Data Required for Shoreline Change Modeling .

Example Inputs for Complex Structure Conf iguracionsri in "START. DAT
Sample Entries Illustrating Development of the WAVES File .

Comparison Between Measured and Hindcast Waves
Calculated Annual Potential Transport Rates

Modified Average Wave Height Because of Shadowing ay Vecain Hanbos

LIST OF FIGURES

Operation of GENESIS through an interface

Shoreline change measured near a long groin .
Comparison of beach change models wees

Major steps in project planning and execution :

Model coordinate system .

Definition sketch for Gnoreline hanes Sealleula tion!
Template to determine the effective sand grain size .
Empirical determination of the depth of closure .
Operation of wave transformation models

Definition of breaking wave angles

Definition sketch for wave calculation

Wave angles in contour modification . oe
Shoreline change as a function of transmission
Example of representative contour i

GENESIS, RCPWAVE, and the overall Caloulacion flow.
Energy windows and transport calculation domains
Diffraction coefficient for two sources

Finite difference staggered grid

Example of a coordinate system and pela need ty GENESIS
Gated boundary condition d Gui Gh iNgle ce
Combinations of lateral houndatys pondietons
Schematic of input and output file structure of GENESIS
Example START file .. .

Example SHORL file

Example SHORM file

Example SEAWL file

Example WAVES files

Example SETUP file

Example OUTPT file :

Example legal structure Slaeemenes

Example illegal structure placements

Parameters associated with detached breatuaters

Legal placement of simple groins :
Examples of complex groin and jetty Confipurseions

LIST OF FIGURES (Continued )

Example illustrating simple seawall configuration .
Example illustrating simple beach fill ha as
Location map for Lorain, Ohio... Sate
Aerial view of Lakeview Park, 17 November 1979
Project design, Lakeview Park .

Adjusted measured shoreline positions .

Measured volume changes within the study area .
Result of model calibration .

Result of model verification . SCA ea deseicn soe hepa
Model sensitivity to changes in K1 KZ candi DSO.
Model sensitivity to changes in K, , HCNGF , and ZCNGA

Shoreline change for alternative structure configurations .

Volume change, October 1977-December 1982 .
Shoreline change, October 1977-December 1982
START file template . Sects th ESD) ee ken TN
SHORL file template .

SEAWL file template .

DEPTH file template .

WAVES file template .

Page
146

147
150
152
154
160
160
168
169
ILZ/al
172
174
177
LY

CONVERSION FACTORS, NON-SI TO SI (METRIC)
UNITS OF MEASUREMENT

Non-SI units of measurement used in this report can be converted to SI

(metric) units as follows:

Multiply By To Obtain
cubic feet 0.02832 cubic meters
cubic yards 0.7646 cubic meters
feet 0.3048 meters
inches Zona millimeters
miles (US statute) 1.6093 kilometers
yards 0.9144 meters

GENESIS: GENERALIZED MODEL FOR SIMULATING SHORELINE CHANGE
TECHNICAL REFERENCE

PART I: INTRODUCTION
GENESIS

1. This report documents a numerical modeling system called GENESIS,
which is designed to simulate long-term shoreline change at coastal engin-
eering projects. The name GENESIS is an acronym that stands for GENEralized
Model for SImulating Shoreline Change. The longshore extent of a typical
modeled reach can be in the range of 1 to 100 km, and the time frame of a
simulation can be in the range of 1 to 100 months. GENESIS contains what is
believed to be a reasonable balance between present capabilities to effi-
ciently and accurately calculate coastal sediment processes from engineering
data and the limitations in both the data and knowledge of sediment transport
and beach change. The modeling system and methodology for its use have
matured through application to numerous types of projects, yet the framework
of the system permits enhancements and capabilities to be added in the future.

2. GENESIS simulates shoreline change produced by spatial and temporal
differences in longshore sand transport. Shoreline movement such as that
produced by beach fills and river sediment discharges can also be represented.
The main utility of the modeling system lies in simulating the response of the
shoreline to structures sited in the nearshore. Shoreline change produced by
cross-shore sediment transport as associated with storms and seasonal varia-
tions in wave climate cannot be simulated; such cross-shore processes are
assumed to average out over a sufficiently long simulation interval or, in the
case of a new project, be dominated by rapid changes in shoreline position
from a nonequilibrium to an equilibrium configuration.

3. The modeling system is generalized in that it allows simulation of a
wide variety of user-specified offshore wave inputs, initial beach configura-
tions, coastal structures, and beach fills by means of an interface, as
depicted in Figure 1. To run the system, the user need only become familiar

with its capabilities and the rules of operation of the interface; details of

the internal structure and algorithms of the computer code need not be
learned. Instructions and data are entered through the interface, which, in
turn, drives the shoreline change calculation.

4. This report provides the background of GENESIS as a coastal engi -
neering tool, describing both its capabilities and limitations, and serves as
a technical reference for operating the modeling system. The methodology of
shoreline change modeling is also presented from the perspective of the total
developmental environment of a shore protection project, since such modeling

cannot be done in isolation from the planning and design processes.

iN
GENESIS

moprnwsmaa-

Figure 1. Operation of GENESIS through an interface

5. Prior to development of GENESIS, each application of a shoreline
change numerical model required extensive modification of an existing model
and, usually, incorporation of special enhancements for the particular
application. Considerable time was spent in altering the internal structure
of the model computer code and testing the predictions. Through experience

gained in a variety of applications over several years, the possibility became

apparent of combining all major features of previous site-specific models into
one generalized shoreline change modeling system. A framework for unifying
model applications was devised by Hanson (1987, 1989) and centers on the
concept of "wave energy windows," described in Part V. Also, an important
task was the development of an interface that would allow a user to interact
easily with the modeling system without demanding specialized knowledge of the
internal code. Much of this report deals with the interface, and technical
details and examples are provided to demonstrate use of the interface as well
as capabilities and limitations of the modeling system.

6. The predecessor model to GENESIS (Kraus 1988a,b,c,d) was developed
in the course of the Nearshore Environment Research Center project conducted
in Japan (Horikawa and Hattori 1987). The structure of GENESIS was developed
by Hanson (1987) in a joint research project between the University of Lund,
Sweden, and the Coastal Engineering Research Center (CERC), US Army Engineer
Waterways Experiment Station. Descriptions of GENESIS Version 1 have been
given by Hanson (1987, 1989).

7. Version 2 of GENESIS, described here, represents a substantial

upgrading of the original model. Major enhancements include:

a. Wave transmission at detached breakwaters.

b. Capability to place either a diffracting or nondiffracting groin
or jetty on a lateral boundary.

c. Inclusion of an arbitrary number of wave sources.

d. Improvement in the interface.

e. Inclusion of warning messages.

Mode of Interaction with GENESIS

8. GENESIS may be installed on various operating systems having
different job control procedures. In this report, discussion of computer
hardware and job control, which vary from office to office and change as
systems change, is not given. System-dependent details are provided separ-
ately with the version of GENESIS at the user’s site. For the purpose of this
manual, it is assumed that an executable file containing GENESIS is loaded on

the system and that it is available to be run. It is also assumed that the

user has familiarity with his or her computer system and basic knowledge of a
computer language such as FORTRAN.
9. In general, there are three basic ways to enter data (instructions

and numerical values) into a model:

a. Direct manipulation method (alteration of the source code).
b. Interactive method (through screen prompts).
c. Interface method (through data files).

10. The direct manipulation method is not a practical alternative for a
large model such as GENESIS because it requires specialized knowledge of the
code, admits the possibility of accidentally altering lines of the code, and
expends computer resources and time in recompilation. Undocumented or
accidental changes in the code at a particular site would greatly increase the
difficulty for CERC to support GENESIS users in the field.

11. The interactive input method is popular in commercial software and
simple modeling systems, such as the Automated Coastal Engineering System
(Leenknecht and Szuwalski 1990), which is composed of modules with relatively
small data input. This method was temporarily rejected for use with GENESIS
because of the great amount of data input required and difficulty of recover-
ing from an input mistake. For example, a mistype might necessitate restart-
ing the session and rekeying previously entered values. Sophisticated and
system-dependent screen control programs would therefore need to be developed
to streamline the data entry and allow recovery from errors. In the future,
however, it is likely that some portion of the data input for GENESIS (in par-
ticular, the "START" file discussed in Part VI) will take advantage of the
interactive data input method in the desktop computer version.

12. GENESIS requires input of several data sets that normally do not
change from run to run (e.g., measured shoreline positions, offshore wave
conditions, and positions of structures). This information must be entered
and accessible from data files for production applications. With considera-
tion of the weaknesses of the direct manipulation and interactive methods,
input to GENESIS is accomplished through use of data files. By using the
interface method, accidental alteration of the code is eliminated, as is time
lost in program compilation, and changes in a few instructions or data values

do not necessitate reentry of unchanged or correct information. Minor changes

1b.

in model input occur frequently during model testing and verification, and the
data files serve as a record of the run. The interface method is also
compatible with a batch mode of computer operation, whereby jobs are submitted
for execution (launched) in an automated manner according to rules of the

particular operating system.

Cautions

13. Numerical modeling of shoreline change is a specialized and highly
technical area of coastal engineering. Firm understanding of coastal hydro-
dynamic and sediment transport processes is a prerequisite to operation of a
shoreline change simulation model. Incautious use of models and incorrect
interpretation of results can lead to costly mistakes. Sophisticated models
such as GENESIS should be operated by trained individuals familiar with the
coast, and results should be examined in light of the observed behavior of the
waves, currents, sediment movement, and beach change that occur along that
coast. To operate GENESIS properly, careful reading of this report is

required.

Scope of This Report

14. This report has two functions. First, it is an introductory
technical reference to GENESIS. The technical material covers the internal
working of GENESIS and is intended to increase understanding of the assump-
tions on which the modeling system is based. Discussion of numerical models
of beach change in general and project planning in association with GENESIS
are given in Parts II and III, respectively. Planners and coastal managers
should read Parts I-IV, as these chapters provide the methodology for use of
the modeling system, a background on shoreline change and other coastal
processes simulation models, and discussion of the limitations and capabil-
ities of GENESIS. Hands-on users of GENESIS should study the entire report,
especially technical aspects presented in Parts V and VI, whereas those who
will not operate GENESIS but only interact with modelers may omit this

material. Because of the nature of addressing the needs of both planners and

engineers, some material is repeated in the different contexts to allow both
groups to achieve understanding of the modeling system.

15. The second function of this report is to serve as an operating
manual for GENESIS, including practice in implementing its principal features.
Part VI begins the manual portion and concerns the structure and use of the
interface consisting of input files and output files. The potential of
GENESIS is demonstrated in Part VII through simple examples that show various
combinations of capabilities of the modeling system. Part VIII presents a
realistic case study that draws on theory and practice developed in
Parts V-VII.

16. Appendix A gives a review of the literature dealing with GENESIS
and its predecessor, covering model development, tests, case studies, and
findings of general interest. Appendix B contains blank input files, which
may be photocopied in preparatory work for running GENESIS. Common error
messages and suggested recovery procedures are given in Appendix C. Input
files for the case study are given in Appendix D. Notation used in this
report is listed in Appendix E. Appendix F is an index.

17. The present report documents Version 2 of GENESIS. It is antici-
pated that additional volumes will provide updates on improvements of GENESIS
that lead to significant enhancements and new versions of the shoreline change
modeling system. Report 2 in the series is scheduled to be a workbook for
power users of GENESIS and will be referred to as the "GENESIS Workbook." The
GENESIS Workbook will be a toolbox containing computer routines developed for
preparing and analyzing data in conjunction with GENESIS. It will also
describe analysis strategies and provide more detailed information on the use

of an external wave transformation model with GENESIS than was possible here.

PART II: OVERVIEW OF BEACH CHANGE MODELS

Need for Models of Shoreline Change

18. Shore protection and beach stabilization are major responsibilities
in the field of coastal engineering. Beach erosion, accretion, and changes in
the offshore bottom topography occur naturally, and engineering in the coastal
zone also influences sediment movement along and across the shore, altering
the beach plan shape and depth contours. Beach change is controlled by wind,
waves, current, water level, nature of the sediment (assumed here to be
composed primarily of sand), and its supply. These littoral constituents
interact as well as adjust to perturbations introduced by coastal structures,
beach fills, and other engineering activities. Most coastal processes and
responses are nonlinear and have high variability in space and time. Although
it is a challenging problem to predict the course of beach change, such
estimations must be made to design and maintain shore-protection projects.

19. In the planning of projects located in the nearshore zone, predic-
tion of beach evolution with numerical models has proven to be a powerful
technique to assist in the selection of the most appropriate design. Models
provide a framework for developing problem formulation and solution state-
ments, for organizing the collection and analysis of data, and, importantly,
for efficiently evaluating alternative designs and optimizing the selected
design. It should be cautioned that models are tools that can be misused and
their correct or incorrect results misinterpreted. Ultimately, it is the
modeler who has responsibility for results and actions taken, not the model.

20. Given the complexity of beach processes, efforts to predict shore-
line change should be firmly grounded on coastal experience, i.e., adaptation
and extrapolation from other projects on coasts similar to the target site.
However, prediction through coastal experience alone, without the support of a
numerical model, suffers limitations.

a. It relies on the judgment of specialists familiar with the
coast and on experience with or histories of previous projects,
which may be limited, inapplicable, or anachronistic. Also,
conflicting opinions can lead to confusion and ambiguity.

It is subjective and does not readily allow comparison of
alternative designs with quantifiable evaluations of relative
advantages and disadvantages.

It is not systematic in that it may not include all pertinent
factors in an equally weighted manner.

It does not allow for estimation of the functioning of novel or
complex designs. This is particularly true if the project is
built in stages separated by long time intervals.

It cannot account for the time history of sand transport as
produced, for example, by natural variations in wave climate,
modifications in coastal structures, and modification in the
beach, as through beach nourishment or sand mining.

£. It does not provide a methodology or criteria to optimize
project design.

21. In summary, complete reliance on coastal experience means that
project decisions are based mainly on the judgment of the engineer and planner
without recourse to external and alternative evaluation procedures. Although
the project engineer must assume full responsibility, use of GENESIS in
applicable situations introduces a means to make objective assessments and

promotes collective analysis of the results.

Shoreline Change Model and Capabilities

22. Over the past decade, a powerful class of numerical models has been
developed that is applicable to the prediction of beach change. These models
are referred to as shoreline change or shoreline response models because they
simulate changes in position of the shoreline in response to wave action and
boundary conditions. The framework for shoreline change models was estab-
lished by Pelnard-Considere (1956), who set down the basic assumptions,
derived a mathematical model, and verified the solution of shoreline change at
a groin with laboratory experiments. Under certain assumptions (to be dis-
cussed) that are valid for many conditions encountered on sandy coasts, these
models can calculate the response of the shoreline to wave action for a wide
variety of engineering situations. Shoreline change models have been applied
in numerous projects, and their usefulness as a planning and design tool has

been confirmed.

23. The shoreline change model predicts shoreline position changes that
occur over a period from several months to several years. The model is best
suited to situations where there is a systematic trend of long-term change in
shoreline position, such as shoreline regression downdrift of a groin or jetty
and advance of the shoreline behind a detached breakwater. The dominant cause
of shoreline change in the model is spatial change in the longshore sand
transport rate along the coast. Cross-shore transport effects such as storm-
induced erosion and cyclical movement of shoreline position as associated with
seasonal variations in wave climate are assumed to cancel over a long simula-
tion period. Cross-shore effects are implicitly included in the model if
measured shoreline positions are used in verification of predictions.

24. Figures 2a-c show an example of shoreline change that is well
suited for modeling. The site is Oarai Beach, located about 180 km north of
Tokyo on the Pacific Ocean coast of Japan. A 500-m-long groin was constructed
to protect a fishing harbor from infiltration by sand carried by the longshore
current. Because of the availability of extensive wave, shoreline position,
and other needed data, this beach proved ideal for development and refinement
of a predecessor shoreline change model of GENESIS (Kraus 1981; Kraus and
Harikai 1983; Kraus, Hanson, and Harikai 1984; Hanson and Kraus 1986b; Kraus
1988a,b,c,d). Figures 2a and 2b show that the shoreline had a clear tendency
to advance on the updrift side of the long groin independent of season if the
interval between compared surveys is taken to be 1 year. Figure 2c gives a
plot of shoreline positions surveyed during each season of 1 year. The
tendency of the shoreline to advance is partially obscured because the
relatively short interval of 3 months includes the effects of individual
storms and other seasonal changes in wave climate, such as change in predomi-

nant wave direction, on shoreline position.
Duration and Extent of Simulation
25. The length of the time that can be modeled depends on the wave and

sand transport conditions, accuracy of the boundary conditions, character-

istics of the project, and whether the beach is near or far from equilibriun.

17,

NY;

SHORELINE POSITION

588

SUMMER POSITIONS

3 (1977 - 1983)
4208 2\

short groin

188 Pe wma ~=Seawall

f= Blocks

a. Summer shoreline positions

WINTER POSITIONS

(1977 - 1982)
short groin
wma ~=9Seawall
cox Blocks
b. Winter shoreline positions
58a
ie POSITIONS 1982
400 + Spring
—-— Summer
—--— Autumn
Winter
308
202 short groin

180 F Seawall

(===: Blocks

a a) 1 1.5 2 Rath
DISTANCE FROM LONG GROIN xX (km)

c. Shoreline positions in four seasons

Figure 2. Shoreline change near a long groin

Immediately after completion of a project, the beach is far from equilibriun,
and changes resulting from longshore sand transport usually dominate over
storm and seasonal changes, with the possible exception of a beach fill.
Shoreline change calculated over a short interval will probably be reliable in
such a case. As the beach approaches equilibrium with the project, the
simulation interval must extend to a number of years. Stated differently, the
shoreline change model best calculates shoreline movement in transition from
one equilibrium state to another.

26. The spatial extent of a target region ranges from the single
project scale of hundreds of meters to the regional scale of tens of kilo-
meters. The modeled longshore extent will depend on the physical dimensions
of the project and boundary conditions controlling the sand transport.
Dimensions of the project are typically at a local scale, whereas placement of
appropriate model boundary conditions may require extension to a more regional
scale. Evaluation of possible effects of the project on neighboring beaches
may also dictate extension of the spatial range of the simulation. Shoreline
change numerical models require modest computer resources and are well suited
for regional scale engineering studies.

27. Shoreline change models are designed to describe long-term trends
of the beach plan shape in the course of its approach to an equilibrium form.
This change is usually caused by a notable perturbation, for example, by
jetties constructed at a harbor or inlet. Shoreline change models are not
applicable to simulating a randomly fluctuating beach system in which no trend
in shoreline position is evident. In particular, GENESIS is not applicable to
calculating shoreline change in the following situations which involve beach
change unrelated to coastal structures, boundary conditions, or spatial
differences in wave-induced longshore sand transport: beach change inside
inlets or in areas dominated by tidal flow; beach change produced by wind-
generated currents; storm-induced beach erosion in which cross-shore sediment
transport processes are dominant; and scour at structures. Table 1 gives a
summary of major capabilities and limitations of Version 2 of GENESIS, which

will be discussed in succeeding chapters.

Table 1
Major Capabilities and Limitations of GENESIS Version 2

Capabilities

Almost arbitrary numbers and combinations of groins, jetties, detached

breakwaters, beach fills, and seawalls
Compound structures such as T-shaped, Y-shaped, and spur groins
Bypassing of sand around and transmission through groins and jetties
Diffraction at detached breakwaters, jetties, and groins
Coverage of wide spatial extent
Offshore input waves of arbitrary height, period, and direction
Multiple wave trains (as from independent wave generation sources)
Sand transport due to oblique wave incidence and longshore gradient in height
Wave transmission at detached breakwaters

Limitations

No wave reflection from structures

No tombolo development (shoreline cannot touch a detached breakwater)
Minor restrictions on placement, shape, and orientation of structures
No direct provision for changing tide level

Basic limitations of shoreline change modeling theory

Comparison of Beach Change Models

28. In this section, capabilities of the shoreline change model are
compared with those of other types of beach change models. Figure 3 extends
and updates the classification scheme of Kraus (1983, 1989), developed for
comparing the capabilities of beach evolution models by their spatial and
temporal domains of applicability. Ranges of model domains were estimated by
consideration of model accuracy and computation costs. These ranges will
expand as knowledge of coastal sediment processes improves, experience is
gained in model usage, wave and shoreline position data become available,

numerical schemes become optimized, and computer costs decrease.

TIME RANGE

MONTHS
(SEASON)

HUNDRED
METERS

OL dA-NNY XVW

fe)
2
=
Oo
>
lew
S)
m
vU
+
ag

SHORELINE
(GENESIS)

LONGSHORE EXTENT
SANIWAYOHS
LN31LX3 SYOHS-SSOHYO

ANALYTICAL
NOLNOO
Q310313S
/ANINSYOHS

BEACH CHANGE PREDICTION MODELS
CLASSIFICATION BY SPATIAL AND TEMPORAL SCALES

Figure 3. Comparison of beach change models

Analytical models of shoreline change

29. Analytical models are closed-form mathematical solutions of a
simplified differential equation for shoreline change. Because of the many
idealizations needed to obtain a closed-form solution, particularly the
requirement of constant waves in space and time, analytical models are too
crude for use in planning or design, except possibly in the preliminary stage
of project scoping. Analytical solutions serve mainly as a means to identify
characteristic trends in shoreline change through time and to investigate
basic dependencies of the change on the incident waves and the initial and
boundary conditions. Larson, Hanson, and Kraus (1987) have given a comprehen-
sive survey of more than 25 new and previously derived analytical solutions of

the shoreline change equation.

Profile erosion models

30. Principal uses of profile erosion models are prediction of beach
change on the upper beach profile produced by storms (Kriebel 1982; Kriebel
and Dean 1985; Larson 1988; Larson, Kraus, and Sunamura 1988; Larson and Kraus
1989b; Larson, Kraus, and Byrnes, in preparation) and initial adjustment of
beach fills to wave action (Kraus and Larson 1988, Larson and Kraus 1989a).
This type of model is simplified by omitting longshore transport processes;
i.e., constancy in longshore processes is assumed so that only one profile at
a time along the coast is treated. In principle, the profile change and
shoreline change models could be used in combination to predict both long- and

short-term changes in shoreline position.

Shoreline change model

31. The shoreline change numerical model, the subject of this report,
is a generalization of analytical shoreline change models. It enables
calculation of the evolution of the shoreline under a wide range of beach,
coastal structure, wave, and initial and boundary conditions, which may vary
in space and time, as appropriate. Despite the assumption of constancy of
beach profile shape alongshore, the shoreline change numerical model has
proved to be robust in predictions and provides a general solution of the
equation governing shoreline change (described in Part V). Because the
profile shape is assumed to remain constant, in principle, landward and
seaward movement of any contour could be used in the modeling to represent
beach position change. Thus, this type of model is sometimes referred to as a
"one-contour line" model or, simply, "one-line" model. Since the mean
shoreline position (zero-depth contour) or similar datum is conveniently
measured, the representative contour line is taken to be the shoreline.
Longshore sand transport together with lateral boundary conditions on each of
the two ends of the model grid are the dominant causes of beach change in the
shoreline change model. Sources of sediment, such as beach fills and river
discharges, as well as sediment sinks, such as inlets and sand mining, can be
accounted for in a phenomenological manner. From this perspective, the
shoreline change numerical model provides an automated means to perform a

time-dependent sediment budget analysis.

Schematic three-dimensional (3-D) models

32. Three-dimensional beach change models describe bottom elevation
changes, which can vary in both horizontal (cross-shore and longshore)
directions. Therefore, the fundamental assumptions of constant profile shape
used in shoreline change models and constant longshore transport in profile
erosion models are removed. Although 3-D beach change models represent the
ultimate goal of deterministic calculation of sediment transport and beach
change, achievement of this goal is limited by the capability to predict wave
climates and sediment transport rates. Therefore, simplifying assumptions are
made in schematic 3-D models, for example, to restrict the shape of the
profile or to calculate global rather than point transport rates. Perlin and
Dean (1978) extended the “two-line model" of Bakker (1968) to an n-line model
in which depths were restricted to monotonically decrease with distance
offshore for any particular profile. Larson, Kraus, and Hanson (in prepara-
tion) treated longshore and cross-shore transport independently in an itera-
tive process and allowed for nonmonotonic depth change, i.e., formation of
bars and berms. Schematized 3-D beach change models have not yet reached the
stage of wide application; they are limited in capabilities because of their
complexity and require considerable computational resources and expertise to
operate. This class of model will probably be the next to be introduced into

engineering practice.

Fully 3-D models
33. Fully 3-D beach change models represent the state of the art of

research and are not widely available for application. Waves, currents (wave-
induced and/or tidal), sediment transport, and changes in bottom elevation are
calculated point by point in small areas defined by a horizontal grid placed
over the region of interest. Use of these models requires special expertise
and powerful computers. Only limited applications have been made on large and
well-funded projects (for example, Vemulakonda et al. 1988, Watanabe 1988).
Because fully 3-D beach change models are used in attempts to simulate local
characteristics of waves, currents, and sediment transport, they require

extensive verification and sensitivity analyses.

Conclusions

34. The shoreline change numerical model is the only general purpose
engineering model presently available for wide application in simulating long-
term evolution of the beach plan shape. This type of model provides a
framework for performing a time-dependent sediment budget analysis under a
wide range of situations encountered in shore-protection projects and requires
only generally available or estimated input data. With the advent of GENESIS,
the potential of the shoreline change model has reached a stage where it can
be operated without expertise in numerical modeling. Numerous refinements can
be expected as the model is tested and adapted to include other phenomena and

engineering activities responsible for causing long-term beach change.

PART III: SHORELINE CHANGE MODELING AS A TOOL IN THE PLANNING PROCESS

Elements of the Planning Process

35. This chapter discusses the role of shoreline change modeling in the
overall process of planning, designing, constructing, and evaluating the
performance of a shore-protection project. The material addresses the
question of how a shoreline change model may be used in the decision-making
process of coastal management and shore protection (Kraus 1989). The purpose
of such planning is to determine the most effective socioeconomic engineering
solution to a shore-protection problem.

36. The planning process broadly consists of the following steps:

a. Formulate problem statement, identify constraints, and develop
criteria for judging the performance or intent of the project.

b. Assemble and analyze relevant data.

c. Determine project alternatives.

d. Evaluate alternatives. (Return to Step a, as necessary.)

e. Select and optimize project design.

£. Construct the project.

g. Monitor the project.

h. Evaluate project according to Step a and report the results.

These steps and their interrelation are shown diagrammatically in Figure 4.
Stages in the planning process where modeling can take an active role are

designated by the word "model."

"Plan regional, engineer local"

37. The problem statement and judgment criteria will usually encompass
diverse factors, requiring comprehensive planning as opposed to single-project
planning. It is essential to imbed the functioning of a project within the
regional coastal processes. Question 1: Will regional processes (for
example, a wide-area tendency to erode) affect the long-term success of a
project; i.e., will the project contradict nature? Question 2: Will the
project have a detrimental impact beyond the immediate area, or will it have a
beneficial effect, such as the downdrift benefit of a beach fill? These types

of considerations lead to the approach "plan regional, engineer local."

(a)

PROJECT PROBLEM STATEMENT

CRITERIA FOR JUDGING PROJECT PERFORMANCE

(b)
ASSEMBLE AND ANALYZE DATA

(MODEL)

(Cc)

IDENTIFY PROJECT ALTERNATIVES
(MODEL)
EVALUATE ALTERNATIVES

(MODEL)

YES

REDEFINE PROJECT?

(e)
OPTIMIZE PROJECT DESIGN
(MODEL)
(f

)
CONSTRUCT PROJECT

(9)
MONITOR PROJECT
(MODEL)
(h)

EVALUATE PROJECT

REPORT RESULTS

Figure 4. Major steps in project planning and execution

Step a

38. A clear problem statement and criteria for judging the project's
functioning must be formulated to determine objectively its degree of success
or failure. The problem statement and judgment criteria should be explicit.
Otherwise, the passage of time between project planning and performance
evaluation may obscure the original purpose, and the functioning or intent of
the project may be evaluated out of context.

39. For example, suppose a section of road along a coast is threatened
by erosion. One possible problem statement is that erosion is endangering a
road between points A and B. A criterion for judging the performance of
the project would be to mitigate or halt the erosion for less than X dollars
in initial construction and less than Y dollars in annual maintenance.
Suppose also that a revetment is selected as the optimal solution and is con-
structed and maintained within budget. Also, monitoring shows that the
project performed as intended in protecting the road. The project has
satisfied the original objectives under single-project planning. However, if
after construction it was determined that the beach downdrift of the project
had eroded because of sand deprivation (caused, for example, by impoundment of
sand by the structure and loss of sand to the system through encasement by the
revetment), it might be judged that the project was a failure. A similar
project might have as its comprehensive planning problem statement protection
of the road and mitigation of anticipated erosion at the downdrift beach.

This would probably lead to a different solution, for example, a revetment to
protect the road fronted by a feeder beach to nourish the downdrift beach. It
is important to distinguish between failures in the planning process and

failures in projects themselves if lessons are to be learned from experience.

Step b

40. All relevant data should be assembled and analyzed with a view of
both defining the problem statement and deciding on a solution approach. In
the example given above, an evaluation of information on shoreline change and
the predominant direction of longshore sand transport would have led to a more

comprehensive problem statement.

Steps c and d
41. Development of a project from the point of problem identification

through construction and performance evaluation involves consideration of five

general issues:

a. Technical feasibility.
b. Economic justification.
ec. Political feasibility.
d. Social acceptability.
e. Legal permissibility.

Technical feasibility concerns the magnitude of the wave, current, and
sediment transport processes at the site; availability of construction
materials; potential constraints on project design because of external
factors; limitations on access to the site; and experience and knowledge of
the staff. Economic feasibility concerns the potential benefits of the
project and is usually the major justification of a project. Funding for
project planning and design staff, construction, maintenance, and monitoring
also enter into the economic justification. Economic justification, political
feasibility, social acceptability, and legal permissibility are closely
related, since local, state, and Federal governments are usually partners in
the funding and permitting of a project.

42. Evaluation of alternatives involves simultaneous assessments of
technical and economic feasibility to arrive at a cost-beneficial design.
During the detailed investigation of alternatives and use of the data base
developed at Step b, it may become apparent that the original problem state-
ment and judgment criteria for the project need to be refined. For example,
project planning may be initiated to satisfy a local need, but later evolve to
consider the primary (site-specific) problem and associated secondary effects

on a regional scale.

Step e

43. Once the best alternative is selected, it is necessary to optimize
the design so that the greatest benefit is obtained for the least cost. As an
example, consider a hypothetical shore-protection project at a state park
which has a beach that is used only lightly for bathing but attracts many

beach walkers and campers. Alternatives identified at Step c are beach fill,

groins, detached breakwaters, or combinations of these elements. After
analysis of park usage, it is decided that a beach fill is not required and,
in any case, could not be maintained because of limited anticipated funding.
The groin alternative is eliminated because a large cross-shore component of
transport exists due to persistent short-period waves. A system of segmented
detached breakwaters combined with a moderate initial fill placed at critical-
ly eroded sections best meets project objectives and is selected for implemen-
tation. At Step e of the planning process, the detached breakwater system
would be optimized by determining the distance for placement offshore,
orientation, gap width between breakwaters, crown height and structure
thickness, construction material, etc., as well as the amount of fill
required. Potential impacts of the project on beachfront properties located

beyond the borders of the park would also be considered.

Steps f and g

44. After the project is constructed, it should be monitored to
ascertain that the final design was properly implemented (and to record
deviations from the design) and to evaluate its performance. The monitoring
plan should be formulated to answer the question of whether the project
achieved its purpose according to the criteria developed at Step a. By
designing the monitoring program to address the problem statement at Step a,
both a productive and economical monitoring plan can be developed. Results of
the project should be published and the processed data archived for use in

future assessments and research and by other projects.

Role of Shoreline Change Modeling

45. Shoreline change modeling is closely associated with and can
greatly aid the planning process described in the preceding section. This

section discusses those relations.

Step b

46. Data requirements of the shoreline change model (discussed in
detail in Part IV) include a wide range of coastal process- and project-
related information. Within the framework of shoreline change modeling,

guidelines are available for collecting, reducing, and analyzing the data ina

systematic manner (as given here and in the GENESIS Workbook). Most physical
data needed for evaluating and interpreting shoreline and beach evolution
processes in a broad sense are used in the shoreline change modeling metho-
dology. Certain other data may be lacking in particular applications having
unique requirements, so that coastal experience and overall project planning
should not be subverted by complete dependence on shoreline change modeling
requirements.

47. Geological and regional factors such as earthquakes, subsidence,
and structure of the sea bottom substrata may indirectly enter into shoreline
change modeling. For example, interpretation of historic shoreline position
change must account for subsidence if it has occurred. Environmental factors
such as water circulation and quality (temperature, salinity, sediment
concentration, etc.), as well as biological factors, may also have to be
considered. For example, although GENESIS can model the movement of beach-
fill material placed at arbitrary locations and times along the beach, the
breeding habits of sea turtles and birds may restrict the season and/or
location of the fill and constrain the project design and construction
schedule. In summary, satisfaction of the data requirements of the shoreline
change model provides an organized and comprehensive first step in assembling

the necessary data for project design.

Steps c-e

48. Provided that shoreline change at the site can be modeled, GENESIS
is well suited for quantitative and systematic evaluation of alternatives and
for optimization of the final plan. As an example, Hanson and Kraus (1986a)
simulated beach change for nine hypothetical combinations of plans to mitigate
erosion at a recreational beach. The without-project ("do nothing") alterna-
tive and several shore-protection schemes were evaluated for groins of various
sizes and spacings, beach fills of various quantities, and a single, long
detached breakwater. Technical criteria for judging the solution involved two
factors, protection of the eroding beach and minimization of the quantity of
sand transported downcoast that would enter the navigation channel of a

fishing harbor. For each alternative, shoreline change modeling allowed

compilation of a matrix of beach change volumes at various sections of the
coast by which the technical solutions could be ranked. Economic consider-

ations were then used to arrive at the most feasible project plan.

Step g
49. In addition to aiding in the evaluation and optimization of project

designs, shoreline response modeling can provide guidance for preparing a
monitoring plan (Step g). Regions of anticipated maximum and minimum shore-
line change or sensitivity can be identified and the monitoring plan struc-
tured to provide data in these important regions. Initial estimates of the
monitoring schedule (frequency of measurements) and density or spacing of

Measurement points can also be made by reference to model predictions.

Conclusions

50. Because of their great power and generality, shoreline change
numerical simulation models such as GENESIS provide a framework for developing
shore-protection problem and solution statements, for organizing the collec-
tion and analysis of data, and, most importantly, for evaluating alternative
designs and optimizing the selected design. Numerical models of beach
evolution extend the coastal experience of specialists and introduce a system-
atic and comprehensive project management methodology to the local engineering
or planning office.

51. This chapter has attempted to demonstrate the utility and benefits
of numerical modeling of coastal processes to the coastal planning and
Management community. Although emphasis was on numerical modeling and beach
processes, it should be recognized that planning and design of a shore-

protection project will involve a wide range of techniques and tools.

PART IV: PROJECT EVALUATION AND USES OF GENESIS

Scoping Mode and Design Mode

52. Depending on the stage of the project study, amount and quality of
data available to operate the modeling system, and level of modeling effort
required, GENESIS can be applied at two different levels, the scoping mode and
the design mode. The scoping mode uses minimal data input and might be
employed in a reconnaissance study to better define the problem and to
identify potential project alternatives. The design mode enters in feasibil-
ity or design studies for which a substantial modeling effort is required.

53. The scoping mode requires the minimum amount of data needed to
characterize a project. A scoping mode application is a schematic study with
such simplifications made as initially straight shoreline and idealized wave
conditions representing, for example, predominant seasonal trends in wave
height, direction, and period. In the scoping mode, the model is an explora-
tory tool for obtaining estimates of relative trends in shoreline change for
different plans. Results from the different alternatives may then be qualita-
tively compared without regard to absolute magnitudes. The scoping mode is a
first attempt at project definition and the investigative stage of solution.

54. In the design mode, the objective is to obtain correct shoreline
change as well as magnitude and direction of the longshore sand transport
rate. The design mode of operation proceeds systematically through data
collection, model setup, calibration and verification, and then to intensive
work to evaluate alternative designs, finally being used to optimize the final
project design. In the design mode, all possible data and ingenuity are
brought to bear in the modeling.

55. The scoping and design modes serve distinct purposes. Similar to
the choice of outpatient treatment at a clinic or full treatment at a hospi-
tal, certain functions may overlap, but the mode of solution should match the
need of the problem. Scoping with GENESIS is made under highly simplified
conditions; it definitely should not be considered as a substitute for a
design mode application of the model, and scoping results should not be

represented as such.

Input Data

56. Identification and evaluation of alternative solutions can begin
once a problem statement has been formulated. Development of a solution and
use of GENESIS are based on physical data and quantification of the processes
involved. The necessity of satisfying data requirements prior to application
of GENESIS systemizes the procedure of data collection and analysis and is a
benefit to all aspects of the project.

57. Various types of data are involved in project evaluation: legal,
financial, cultural, environmental, and physical. Here only physical data are
considered. Physical data are required for two purposes:

To obtain background information for making a general and
integrated assessment of coastal processes at the site and of
the geographic region.

(Sy)

b. To calibrate, verify, and make predictions with GENESIS.
Complete guidance covering item a cannot be given, as each project will have
unique characteristics. Coastal engineering and geological experience must be
relied upon to determine special factors, physical and environmental, which
may affect project design and performance. The present section deals with
item b, data necessary to run GENESIS. However, since the data sets needed to
run GENESIS encompass many aspects of coastal processes, clues pointing toward
site-specific data requirements can be expected.

58. The first technical step in a modeling task is to establish a
shoreline coordinate system. The regional trend of the coast is determined
from a wide-scale chart, whereas the trend of the local shoreline is deter-
mined from a small-scale chart. The regional trend is used to identify the
orientation of offshore contours for wave refraction modeling, whereas
shoreline positions, structure configurations, and other project-specific
information are referenced to the small-scale chart.

59. A decision is made on the trend of the shoreline, and a longshore
(x) axis is drawn parallel to the trend. A shore-normal (y) axis is then
drawn pointing offshore to create a right-hand system, as shown in Figure 5.
Based on the availability and quality of data, extent of the modeled area,
detail desired, and the level of effort, the grid spacing is specified.

Typical longshore spacing is 25, 50, or 100 m if working in the metric system,

and 50, 100, 200, or 500 Gite working in American customary units. GENESIS
requires no cross-shore grid spacing. The coordinate system and grid are
established early in the project, as all geographic information (shoreline
positions; locations of structures, beach fills, and river mouths; bathymetry;
wave input; etc.) must be referenced to the same coordinate system and datum

and this information may be prepared by different individuals.

TREND OF OFFSHORE BOTTOM CONTOURS

Wis OREM ET eT me Mondor ese Soe ec) ta a! py yi
a ee ee cee NS DO IOS OS rhea Ie yt
(e)

122)

[ire

z SHORELINE

I | PROJECT LATERAL COORDINATE

2 a PROJECT LATERAL

BOUNDARY
SHORELINE

pane x
DISTANCE ALONGSHORE
LONGSHORE

GRID SPACING

Figure 5. Model coordinate system

60. Discussion of input data requirements will center on Table 2 (see
also, Tanaka 1988). This table can also be used at the start of project
planning as a checklist for needed data. Only a small portion of the data
listed are used directly by GENESIS. The minimal information required is:

a. Shoreline position.

b. Waves.

“ A table of factors for converting non-SI units of measurement to SI

(metric) units is presented on page 8.

¢. Structure configurations and other engineering activities.
d. Beach profiles.
e. Boundary conditions.

The other data listed in Table 2 are needed for interpretation of sediment
transport processes and beach change. For example, coastal subsidence or an
earthquake might produce an apparent trend in shoreline recession unrelated to

longshore sand transport or boundary conditions.

Shoreline position

61. Shoreline position data can be obtained from shoreline surveys,
beach profile surveys, aerial photographs, maps, and nautical charts.
Shoreline positions should be referenced to the longshore baseline and values
interpolated to longshore grid points so that shoreline positions calculated
with GENESIS can be easily compared. The terminology "shoreline position"
usually refers to the zero-depth contour with respect to a certain datum, for
example, mean sea level (MSL) or to mean lower low water (MLLW). All shore-
line position and bathymetry data for wave refraction modeling should be
referenced to the same datum.

62. Plots of shoreline positions may reveal errors in the data as well
as trends in shoreline change. As much as possible, the two surveys defining
the calibration and verification intervals should be in the same season to

minimize the effect of the seasonal cyclical displacement of the shoreline.

Offshore waves

63. It is rare to have adequate wave gage data for a modeling effort.
If gage data are not available, hindcasts can be used. The Wave Information
Study (WIS) (e.g., Jensen 1983a,b; Jensen, Hubertz, and Payne 1989) provides
hindcast estimates of height, period, and direction at intervals along all
continental US coasts. Gravens (1988) discusses a methodology for use of WIS
data in calculation of potential longshore sand transport rates.

64. At the lowest level of effort, statistical summaries of hindcasts
can be used. In typical design mode shoreline change modeling projects per-
formed at CERC, offshore wave data are input at 6-hr intervals over the
simulation period. Actual wave height in the time series is used, but wave

period and direction are grouped into approximately 50 to 100 categories or

period-direction bands to limit the number of distinct wave transformation

calculations that must be made. This topic is discussed further in Part V.

Table 2
Data Required for Shoreline Change Modeling

Type of Data Comments
Shoreline position Shoreline position at regularly spaced intervals

alongshore by which the historic trend of beach
change can be determined.

Offshore waves Time series or, at a minimum, statistical summaries of
offshore wave height, period, and direction.

Beach profiles and Profiles to determine the average shape of the
offshore bathymetry beach. Bathymetry for transforming offshore
wave characteristics to values in the nearshore.

Structures and Location, configuration, and construction
other engineering schedule of engineering structures (groins,
activities jetties, detached breakwaters, harbor and port break-

waters, seawalls, etc.). Structure porosity, reflec-
tion, and transmission. Location, volume, and
schedule of beach fills, dredging, and sand mining.
Sand bypassing rates around jetties and breakwaters.

Regional transport Identification of littoral cells and transport paths.
Sediment budget. Locations of inlets. Wind-blown
sand transport.

Regional geology Sources and sinks of sediment (river discharges, cliff
erosion, submarine canyons, etc.). Sedimentary
structure. Grain size distribution (native and of
beach fill). Regional trends in shoreline movement.
Subsidence. Sea level change.

Water level Tidal range. Tidal and other datums.

Extreme events Large storms (waves, surge, failure of structures,
etc.). Inlet opening or closing. Earthquakes.

Other Wave shadowing by large land masses. Strong coastal
currents. Ice. Water runoff.

65. In a scoping mode, or if the offshore contours are parallel to the
trend of the shoreline and the extent of the project to be modeled is small
(for example, shoreline change at a single detached breakwater), the simple
wave transformation routine (internal model) in GENESIS can be used to
refract, shoal, and diffract waves. GENESIS will transform the waves from the
depth of the offshore gage or hindcast point and produce the pattern of
breaking waves alongshore for calculating the longshore sand transport rate.

66. If offshore contours are irregular or the project is of wide
extent, a specialized wave transformation program must be used to propagate
the waves from offshore to nearshore for use by GENESIS. Any wave model can
be used to provide the required information. At CERC, the model RCPWAVE
(Regional Coastal Processes WAVE model) (Ebersole, Cialone, and Prater 1986)
is used to supply the needed nearshore wave information.

67. Shoreline change is sensitive to wave direction, and this quantity
is the most difficult to estimate. If information on wave direction is not
available, wind direction from a nearby meteorological station, buoy, Coast
Guard station, or airport may be useful, as well as consideration of possible
fetches. The effects of the coastal boundary layer and daily and seasonal
trends in wind speed, gustiness, and direction should be taken into account.

68. The wave input interval (time step), statistics of the waves, and
the period to be covered must also be determined. For shoreline change model
calibration and verification, either hindcast data or the actual wave record
occurring over the simulation interval should be used, if available. In
simulations involving long periods and wide spatial extent, it may be imprac-
tical to handle a wave data file covering the full simulation period.
Instead, a shorter wave data file can be used and repeated, a capability
provided by GENESIS. The shorter record is fabricated by comparing statistics
of the total available wave data set (gage or hindcast) by year, season, and
month. Typical quantities that should be preserved are average significant
wave height and period, maxima of these quantities, average wave direction,
and occurrence of storms. For example, a 5-year record might be composed of
1 year of more frequent storms (but not the extreme year as that would not be
representative), a year of relatively low waves, and 3 years judged to be

atypical."

Bathymetry and profiles

69. If a wave refraction model is used, hydrographic charts are needed
to digitize the bathymetry onto the numerical grid. For users with sufficient
computer hardware and related capabilities, bathymetric data for US coasts may
be obtained on magnetic media from the National Oceanic and Atmospheric
Administration (NOAA) and then interpolated to the grid. The nearshore
information from bathymetric charts can be compared with available beach
profile surveys. Profile surveys often extend to a nominal depth of 10 m
(30 ft), providing information to supplement the charts. If calibration and
verification simulation intervals are in the far past (for example, in the
19th century), bathymetric data from that period should be used, not the
present bathymetry. This is especially pertinent if an inlet is included in
the wave modeling grid, since ebb shoals can greatly change.

70. Profile data are used to estimate three quantities required to
operate GENESIS: the average height of the berm, the depth of closure
(seaward limit of significant sediment movement), and the average profile
slope.

71. Bathymetric and profile data are also used to establish a general
sediment budget, to locate scour at structures, to infer sediment paths and
flow channels, to identify local areas of deposition and erosion, and to
qualitatively estimate and distinguish cross-shore transport and longshore

transport effects at structures in some situations.

Structures and other
engineering activities
72. Structures and other engineering activities, such as placement of

beach fill, must be correctly located on the grid both in space and time.
Procedures for accomplishing this are described in Parts VI and VII. Also,
GENESIS allows representation of changes in structures through time as, for
example, extension of a breakwater, construction of a groin field during the
simulation interval, or multiple placements of beach fill. Therefore, in data
collection and project planning, the locations, configurations, and times (and
volumes in the case of beach fills, dredging, and sand mining) must be

assembled.

73. Other types of data may be required in certain situations. Some of
these items are difficult to quantify, such as permeability factors for groins
and transmission factors for detached breakwaters; nevertheless, estimates
must be made. Final values of these ambiguous quantities are usually deter-
mined in the model verification process. In these situations, special care
must be given to check inferences against field data on shoreline change at

the site.

Regional sediment transport
74. Sediment transport and shoreline change at the site should be

interpreted within a regional context, as there may be a "far field" effect on
the project from processes quite distant from it and vice versa. If possible,
the project is placed within the context of a littoral cell, which is a
coastal area defined by known or well-estimated sediment fluxes at lateral
boundaries. Examples of good lateral boundaries are large inlets and
entrances, harbor breakwaters and long jetties, and regions that have experi-
enced little shoreline change. A sediment budget is made for the littoral
cell (Shore Protection Manual (SPM) 1984, Chapter 4), and this analysis may be
repeated in gradual stages of sophistication, leading into a production
modeling effort with GENESIS. Such a simple budget analysis might be termed
"first-order modeling" and gives an integrated and regional perspective of the
dominant processes to serve as guidance in interpreting the more extensive and
quantitative results produced by shoreline change models. Information that
should be gathered in this task are estimates of direction and amounts of net
longshore sediment transport; gross sediment transport; trends in shoreline
change; and seasonal variations in waves, currents, sediment transport, and

beach change.

Regional geology

75. Collection and analysis of geologic and geomorphic data are linked
with the study of regional transport processes in development of the sediment
budget. Typical subjects of the regional geology portion of the study include
estimation of the effects of inlets, both as sources and as sinks of littoral
material; river discharges; special sources of littoral material, such as

cliffs; sea level rise and subsidence; and analysis of grain size. The

geologic history of the coast, the when, how, and of what it was formed, also

provides important background material.

Water level

76. If the tidal range is large, wave refraction and breaking will vary
significantly according to the water level. For micro- and mesotidal coasts,
use of either the MSL or MLLW datums (either of which appears on NOAA bathy-
metric charts) is considered sufficient. If the tide variation is appreci-
able, refraction simulations with different water levels may be necessary.
Water level also plays a role in wave overtopping and transmission through
breakwaters, sediment overtopping and bypassing (shoreward and seaward) at
groins, and interpretation of shoreline position from aerial photographs.

77. Version 2 of GENESIS does not allow direct representation of tidal
change. However, changes in breaking waves as caused by variations in water

level can be represented in the wave input.

Extreme events

78. The aim of shoreline modeling is to simulate long-term change in
shoreline position; effects of extreme events are assumed to be accounted for
in the verification process. An extreme event is a natural process or
engineering activity that causes a substantial, perhaps irreversible, change
in the shoreline position. Without documentation of such events, interpreta-
tion of shoreline change could be mistaken. Examples of extreme events are
storms of record that greatly erode the beach and dredging during construction
of coastal structures. It is possible that one or more extreme events may
have dominated shoreline change over the interval between shoreline surveys.
This is particularly likely if the calibration or verification intervals are
relatively short and an extreme event is bracketed. It is important to have
documentation on extreme events so that shoreline and beach processes can be
properly interpreted. If possible, time intervals that span known extreme
events (including, for example, beach fills of unspecified volume) should be

avoided in the calibration/verification process.

Other
79. Each site or project brings novel problems, and it is rare that

standard operating procedure can be completely followed in a shoreline

modeling effort. Coastal experience must be relied upon to identify unique
characteristics of the site or a normally minor factor that may, for some
reason, occupy a position of prominence in the coastal processes. These types
of problems may often be treated by creative exercise of GENESIS’s many
features, but sometimes special expertise is required to allow a description

of unique situations with GENESIS.

Boundary Conditions

80. As discussed further in Parts V, VI, and VII, boundary conditions
must be specified at the two lateral ends of the numerical grid. Boundary
conditions determine the rate at which sand may enter and leave the modeled
area and can have a profound effect on shoreline change.

81. There are situations in which it may be possible to eliminate the
influence of boundary conditions by placing the boundaries far from the
project so as to have a negligible effect over the simulation interval. For
example, if a project is highly localized, such as a single detached break-
water on a straight sandy beach, the boundaries may be placed several project
lengths to either side and a condition of no shoreline change imposed, as the
breakwater system is expected to modify only the local area and not completely
block longshore sediment transport. In more regional applications, represen-
tation of the naturally occurring boundary conditions must be addressed as
part of the problem.

82. In situations where the boundary conditions are ill-defined (which
is the typical situation in applications), it is of great help to monitor the
net and gross longshore sand transport rates calculated by GENESIS (Part V) in
addition to shoreline change. Boundary conditions control the magnitude of
the longshore sand transport rate. GENESIS provides information on the
calculated transport rate for comparison to empirically determined rates or to
rates that have to be specified by assumption (for example, at a rocky cliff).
In many cases, one or both boundaries are an integral part of the project,
such as shoreline change at a long jetty or shore-connected harbor breakwater,
blockage of longshore transport at an inlet or navigation channel, or termina-

tion of the beach at a headland.

83. GENESIS allows representation of two general boundary conditions,
termed a "pinned-beach" condition and a "gated" condition. If the position of
the shoreline can be assumed to be stationary, this condition defines a pinned
beach. A pinned beach boundary is appropriate if the sediment budget is
balanced at the boundary segment of the beach, meaning that the input and
output volumes of beach material at the boundary are equal on an average
annual basis. A pinned beach boundary may also be imposed if the beach is
constrained (e.g., by a rocky cliff or seawall), but sediment can still move
alongshore and past the boundary area.

84. A gated boundary condition describes the case of some preferential
gain or loss of sand at the boundary; in other words, the boundary influences
the transport rate. As a simple example, if a jetty is very long, no sand is
expected to flow onto or off the grid at that location. As another example,
at some inlets sand may move alongshore and off the grid into the navigation
channel running through the inlet, but sand cannot move onto the grid from the
inlet (except possibly in an extreme wave event). The inlet thus acts as a
gate or rectifier of transport, allowing sand to escape from the project reach
but not to enter. Specific examples and hands-on experience in prescribing

these conditions are given in Part VI.

Variability in Coastal Processes

Problem of variability

85. Waves bring an enormous amount of energy to the coast, and this
energy is dissipated through wave breaking, generation of currents, water
level changes, movement of sand, turbulence, and heat. Incident waves vary in
space and time, and their properties also change as they move over the sea
bottom. The beach is composed of sediment particles of various sizes and
shapes which move along and across the shore controlled by laws that are not
well known. This sediment is transported by complex three-dimensional
circulation patterns of various spatial and time scales and degrees of
turbulence. The beach and back-beach also exhibit different textural proper-
ties that vary alongshore, across-shore, and with time. In light of the

profound variability of coastal processes, it is clear that a single answer

obtained with a deterministic simulation model must be viewed as a representa-
tive result that has smoothed over a large number of unknown and highly
variable conditions.

86. Similarly, in use of a deterministic model in a predictive mode,
the factors responsible for beach change (in the case of GENESIS, primarily
the waves) are not known. A time series of wave height, period, and direction
must be forecast for use in the prediction and can be considered as only one

of many possible wave climates that might occur.

Accounting for variability
87. Since there is great variability in the nearshore system, any one

prediction of shoreline change cannot be the correct answer. Several studies
have been made on wave variability and shoreline change prediction (Kraus and
Harikai 1983; Le Méhauté, Wang, and Lu 1983; Kraus, Hanson, and Harikai 1984;
Hanson and Kraus 1986a; Hanson 1987; Walton, Liu, and Hands 1988), and some
guidance has been developed for use in the prediction process. These referen-
ces should be consulted to supplement discussion given here.

88. A simple procedure used at CERC to estimate the effect of wave
variability is to compute the standard deviation of the wave height and
direction in the input wave time series and then adjust values of the input
waves through a range defined by these deviations. GENESIS allows adjustment
of wave height and direction by user-specified amounts. Wave period is not
normally varied, but in certain applications, such as a situation involving
waves of long periods or a sea bottom with highly irregular features, the
refraction pattern will be particularly sensitive to wave period. Another
procedure uses different hindcast time series if such data are available. By
varying the input wave height and direction within a physically reasonable
range, a series of shoreline change predictions is made within which the
actual change is expected to lie. Variation of input parameters is also part
of the sensitivity analysis to be performed to obtain some idea of model

dependence on empirical parameters, as discussed in a later section.

Calibration and Verification

89. Model calibration refers to the procedure of reproducing with a
model the changes in shoreline position that were measured over a certain time
interval. Verification refers to the procedure of applying the calibrated
model to reproduce changes measured over a time interval different from the
calibration interval. The terms "calibration" and "verification" are often
referred to as "verification" alone, since verification implies that calibra-
tion has been done. Successful verification is taken to indicate that model
predictions are independent of the calibration interval (i.e., that the
empirical coefficients and boundary conditions remain constant for the coast),
but it does not guarantee this independence, and conditions can easily change,
which will void the verification process. For example, a boundary condition
of unrestricted sand transport (pinned beach) may change to a gated boundary
condition after construction of an entrance channel through the beach. The
modeler must be aware of significant changes in the physical situation that
might invalidate the original verification and require new verification.

Also, the available wave data set may better represent the wave climate that
existed during some calibration and verification periods than other periods.

90. In practice, data sets sufficiently complete to perform a rigorous
calibration and verification procedure are usually lacking. Typically, wave
gage data are not available for time intervals between available measured
shoreline positions, and unambiguous and complete data on historical shoreline
change are often unavailable. This situation increases the number of unknowns
in the modeling process and thereby reduces reliability of the calculation.

In the absence of hard data, estimates of shoreline change with the model may
provide the only source of systematic and quantitative information with which
to make planning decisions. In situations where data are lacking, coastal
experience and experience with GENESIS must be relied upon to supply reason-
able estimates of input parameters and to interpret calculated results.

91. Model predictions are readily compared by graphical means. Plots
are made of calculated and measured shoreline positions, normally at exag-
gerated vertical scales (shoreline position coordinate). Shoreline positions

can also be manipulated mathematically to determine in a least-squares sense,

for example, the combination of parameters producing the best match of
calculated and measured values. This provides an objective measure of
goodness of fit, whereas visual inspection is somewhat subjective. However, a
mathematically based criterion should always be checked by visual inspection
of shoreline position plots as cancellation of errors is prone to happen for

sinuous shorelines and may produce a misleading measure of goodness of fit.

Sensitivity Testing

92. Sensitivity testing refers to the process of examining changes in
the output of a model resulting from intentional changes in the input. If
large variations in model predictions are produced by small changes in the
input, calculated results will depend greatly on the quality of the verifica-
tion, which is usually in some degree of doubt in practical applications. A
second reason for conducting sensitivity tests concerns the natural varia-
bility existing in the nearshore system, as discussed in a previous section.
No single model prediction can be expected to provide the correct answer, and
a range of predictions should be made and judgment exercised to select the
most probable or reasonable result. If the model is oversensitive to small
changes in input values, the range of predictions will be too broad and, in
essence, provide no information. Experience has shown that GENESIS is usually
insensitive to small changes in parameter values. Nevertheless, sensitivity

testing should always be done.

Interpretation of Results

93. Results should always be checked for general reasonability. In
this regard, an overview of regional and local coastal processes and the
sediment budget calculation or first-order modeling discussed previously
should be employed to judge model results. For example, is the overall trend
of the calculated shoreline position correct and not just the dominant
feature? Do the magnitude and direction of the calculated longshore sand
transport rate agree with independent estimates? Experience gained in the

verification, sensitivity analysis, and modeling of alternative plans will

help uncover erroneous or misleading results. Plots of computed shoreline
positions reveal obvious modeling mistakes, whereas more subtle errors of
either the model or modeler can be found in the sensitivity analysis through
understanding of basic dependencies of shoreline change on the wave input and
boundary conditions.

94. Shoreline change is governed by nonlinear processes, many of which
are represented in GENESIS. Complex beach configurations and time-dependent
wave input will produce results that cannot be extrapolated from experience.
However, as much as possible, experience should be called upon to evaluate the
correctness of results and to comprehend the trends in shoreline change
produced.

95. Finally, the user must maintain a certain distance from model
results. It should be remembered that obliquely incident waves are not
responsible for all longshore sand transport and shoreline change. Potential
errors also enter the hindcast of the incident waves, in representing an
irregular wave field by monochromatic waves and, sometimes, through undocu-
mented human activities and extreme wave events that have modified the beach.
The probable range in variability of coastal processes must also be considered

when interpreting model results.

PART V: THEORY OF SHORELINE RESPONSE MODELING AND GENESIS

96. In this chapter the theory of shoreline response modeling and its
mathematical representation in GENESIS are described, including the numerical
implementation of major calculation procedures. The physical and mathematical
foundation of GENESIS and its internal structure are, therefore, the main
subjects. External structural elements for operating the modeling system,
i.e., the user interface and input/output files, are described in Part VI.

97. The basic assumptions underlying shoreline response modeling are
first presented, and the equations used in GENESIS to calculate the longshore
sand transport rate and shoreline change are introduced. The chapter also
gives an overview of the wave calculation model internal to GENESIS. Impor-
tant constructs unique to GENESIS, notably the concepts of wave energy windows
and transport domains, are discussed, as are boundary conditions and con-

straints on the transport rate and position of the shoreline.

Basic Assumptions of Shoreline Change Modeling

98. A common observation is that the beach profile maintains an average
shape that is characteristic of the particular coast, apart from times of
extreme change as produced by storms. For example, steep beaches remain steep
and gently sloping beaches remain gentle in a comparative sense and in the
long term. Although seasonal changes in wave climate cause the position of
the shoreline to move shoreward and seaward in a cyclical manner, with
corresponding change in shape and average slope of the profile, the deviation
from an average beach slope over the total active profile is relatively small.
Pelnard-Considere (1956) originated a mathematical theory of shoreline
response to wave action under the assumption that the beach profile moves
parallel to itself, i.e., that it translates shoreward and seaward without
changing shape in the course of eroding and accreting. He also verified his
mathematical model by comparison to beach change produced by waves obliquely
incident to a beach with a groin installed in a movable-bed physical model.

99. If the profile shape does not change, any point on it is sufficient

to specify the location of the entire profile with respect to a baseline.

Thus, one contour line can be used to describe change in the beach plan shape
and volume as the beach erodes and accretes. This contour line is conven-
iently taken as the readily observed shoreline, and the model is therefore
called the "shoreline change" or "shoreline response" model. Sometimes the
terminology "one-line" model, a shortening of the phrase "one-contour line"
model, is used with reference to the single contour line.

100. A second geometrical-type assumption is that sand is transported
alongshore between two well-defined limiting elevations on the profile. The
shoreward limit is located at the top of the active berm, and the seaward
limit is located where no significant depth changes occur, the so-called depth
of profile closure. Restriction of profile movement between these two limits
provides the simplest way to specify the perimeter of a beach cross-sectional
area by which changes in volume, leading to shoreline change, can be computed.

101. The model also requires predictive expressions for the total long-
shore sand transport rate. For open-coast beaches, the transport rate is a
function of the breaking wave height and direction alongshore. Since the
transport rate is parameterized in terms of breaking wave quantities, the
detailed structure of the nearshore current pattern does not directly enter.

102. Finally, it is assumed that there is a clear long-term trend in
shoreline behavior. This must be the case in order to predict a steady signal
of shoreline change from among the "noise" in the beach system produced by
storms, seasonal changes in waves, tidal fluctuations, and other cyclical and
random events. In essence, the assumption of a clear trend implies that the
wave action producing longshore sand transport and boundary conditions are the
major factors controlling long-term beach change. This assumption is usually
well satisfied at engineering projects involving groins, jetties, and detached
breakwaters, which introduce biases in the transport rate.

103. In summary, standard assumptions of shoreline change modeling are:

a. The beach profile shape is constant.

b. The shoreward and seaward limits of the profile are constant.

c. Sand is transported alongshore by the action of breaking
waves.

d. The detailed structure of the nearshore circulation is
ignored.

e. There is a long-term trend in shoreline evolution.

104. The basic assumptions define a flexible and economical shoreline
change simulation model that has been found applicable to a wide range of
coastal engineering situations. However, it should be kept in mind that the
assumptions are idealizations of complex processes and, therefore, have
limitations. Ina strict sense, the assumption that the beach profile moves
parallel to itself along the entire modeled reach is violated in the vicinity
of structures. For example, the slope of the profile on the updrift or
accreting side of a jetty or long groin is usually more gentle than the slope
of the beach distant from the structure. GENESIS will show shoreline advance
in such a case, and a calibrated model may provide agreement with measured
shoreline change, but the change in beach slope and sand volume contained in
that change will not be reproduced. As a result, simulations in situations
where the beach slope is expected to change significantly should be inter-
preted carefully.

105. Similarly, the depth of closure and the berm height along the
modeled stretch of beach may vary alongshore, whereas these quantities are
constant in the model. Values for berm elevation and depth of profile closure
representative of the entire beach must be carefully determined. The trans-
port rate formula contained in Version 2 of GENESIS describes longshore sand
transport produced solely by incident waves. It does not describe transport
produced by tidal currents, wind, or other forcing agents, indicating that the
model should not be used if breaking waves are not the dominant mechanism for
transport sand alongshore. As described below, GENESIS can account for the
vertical and cross-shore distributions of longshore sand transport at groins
and jetties in an empirical fashion. It does not account for the full
vertical and horizontal water and sand circulation, making it incapable, for
example, of describing transport by rip currents, undertow or return flow, or
other 3-D fluid and transport processes.

106. The assumption that there must be a long-term trend in shoreline
evolution means that a boundary condition or some other systematic process,
for example, a river discharge, or a regular change in the wave pattern such
as produced by a detached breakwater, dominates the beach change. This will

normally be the case at engineering projects.

Governing Equation for Shoreline Change

107. The equation governing shoreline change is formulated by conserva-
tion of sand volume. Consider a right-handed Cartesian coordinate system in
which the y-axis points offshore and the x-axis is oriented parallel to the
trend of the coast (Figure 6). The quantity y” thus denotes shoreline posi-
tion, and x denotes distance alongshore. It is assumed that the beach
profile translates seaward or shoreward along a section of coast without
changing shape when a net amount of sand enters or leaves the section during a
time interval At . The change in shoreline position is Ay , the length of
the shoreline segment is Ax , and the profile moves within a vertical extent
defined by the berm elevation Dg, and the closure depth D,. , both measured
from the vertical datum (for example, MSL or MLLW).

108. The change in volume of the section is AV = AxAy(D, + DD.) and is
determined by the net amount of sand that entered or exited the section from
its four sides. One contribution to the volume change results if there is a
difference AQ in the longshore sand transport rate Q at the lateral sides
of the cells. This net volume change is AQAt = (dQ/dx)AxAt . Another
contribution can arise from a line source or sink of sand q = q, + q, , which
adds or removes a volume of sand per unit width of beach from either the
shoreward side at the rate of q, or the offshore side at the rate of q.
These produce a volume change of qAxAt . Addition of the contributions and
equating them to the volume change gives AV = AxAy(D, + Dc) = (dQ/dx)AxAt
+ qAxAt . Rearrangement of terms and taking the limit as At —>0 yields

the governing equation for the rate of change of shoreline position:

Gayle. stile aint (.2Q%,, ] -
ieee le Bee (1)

109. In order to solve Equation 1, the initial shoreline position over
the full reach to be modeled, boundary conditions on each end of the beach,

and values for Q,q_, Dg , and De must be given.

For convenience, symbols and abbreviation are listed in the Notation
(Appendix E).

pD. ~~ WATER
LEVEL
DATUM

a. Cross-section view

DISTANCE OFFSHORE Y

DISTANCE ALONGSHORE

b. Plan view
Figure 6. Definition sketch for shoreline change calculation

Syl

Sand Transport Rates

Longshore sand transport

110. The empirical predictive formula for the longshore sand transport

rate used in GENESIS is

Q = (HC), [a sin26,, = a, cosé,. ae (2)
where
H = wave height
C, = wave group speed given by linear wave theory
b = subscript denoting wave breaking condition
6,4, = angle of breaking waves to the local shoreline

The nondimensional parameters a, and a, are given by

Ky
>) | He @i/pien) Geep) Gate)

and (3)
Ko
“2 '8(p,/p - 1) - p)tanf(1.416)"”

where
K,, K, = empirical coefficient, treated as a calibration parameter
p, = density of sand (taken to be 2.65 10° kg/m? for quartz sand)
p = density of water (1.03 10 kg/m? for seawater)
Pp = porosity of sand on the bed (taken to be 0.4)

tanB = average bottom slope from the shoreline to the depth of active
longshore sand transport

The factors involving 1.416 are used to convert from significant wave height,
the statistical wave height required by GENESIS, to root-mean-square (rms)

wave height.

111. The first term in Equation 2 corresponds to the "CERC formula"
described in the SPM (1984) and accounts for longshore sand transport produced
by obliquely incident breaking waves. A value of K, = 0.7/7 was originally
determined by Komar and Inman (1970) from their sand tracer experiments, using
rms wave height in the calculations. Kraus et al. (1982) recommended a
decrease from 0.77 to 0.58 on the basis of their tracer experiments. As this
order of magnitude for K, is well known in the literature, the standard
engineering quantity of significant wave height is converted to an rms value
by the factor 1.416 to compare values of K, determined by calibration of the
model. The design value of K typically lies within the range of 0.58 to
Ose

112. The second term in Equation 2 is not part of the CERC formula and
is used to describe the effect of another generating mechanism for longshore
sand transport, the longshore gradient in breaking wave height 0H,/dx . This
contribution to the longshore transport rate was introduced into shoreline
change modeling by Ozasa and Brampton (1980). The contribution arising from
the longshore gradient in wave height is usually much smaller than that from
oblique wave incidence in an open-coast situation. However, in the vicinity
of structures, where diffraction produces a substantial change in breaking
wave height over a considerable length of beach, inclusion of the second term
provides an improved modeling result (Kraus 1983; Kraus and Harikai 1983;
Mimura, Shimizu, and Horikawa 1983), accounting for the diffraction current.

113. Although the values of K, and kK, have been empirically esti-
mated, these coefficients are treated as parameters in calibration of the
model and will be called "transport parameters" hereafter. The transport
parameter kK, controls the time scale of the simulated shoreline change, as
well as the magnitude of the longshore sand transport rate. This control of
the time scale and magnitude of the longshore sand transport rate is performed
in concert with the factor 1/(D, + D~) appearing in Equation 1, as discussed
in a later section. The value of K, is typically 0.5 to 1.0 times that of
K, . It is not recommended to vary kK, much beyond 1.0K, , as exaggerated
shoreline change may be calculated in the vicinity of structures and numerical

instability may occur.

114. In summary, because of the many assumptions and approximations
that have gone into formulation of the shoreline response model, and to
account for the actual sand transport along a given coast, the coefficients
K, and K, are treated as calibration parameters in the model. Their values
are determined by reproducing measured shoreline change and order of magnitude

and direction of the longshore sand transport rate.

Sources and sinks

115. The quantity q in Equation 1 represents a line source or sink of
sand in the system. Typical sources are rivers and cliffs, whereas typical
sinks are inlets and entrance channels. Wind-blown sand at the shore can act
as either a source or sink on the landward boundary, depending on wind
direction. General predictive formulas cannot be given for the shoreward and
seaward rates q, and q, , whose values depend on the particular situation.
These quantities typically vary with time and are a function of distance
alongshore. Kraus and Harikai (1983) modeled the effects of river discharge
and subsequent sand shoaling on the beach by means of a source term. The
capability to represent sources and sinks is not included in Version 2 of
GENESIS. As an alternative, a beach-fill volume (shoreline advance or

retreat) providing the same rate as a source or sink can be implemented.

Direct change in shoreline position
116. The position of the shoreline can also change directly, for

example, as a result of beach fill or dredging. In this case, the profile is
translated shoreward or seaward, as required, by a specified amount that can
be a function of time and distance alongshore. GENESIS allows specification
of a direct change in shoreline position, which may be positive (seaward), as

caused by beach fill, or negative (landward), as by sand mining.

Empirical Parameters

Depth of longshore transport
117. The width of the profile over which longshore transport takes

place under a given set of wave conditions is needed to estimate the amount of
sand (percentage of total) bypassing occurring at groins and jetties. Since

the major portion of alongshore sand movement takes place in the surf zone,

this distance is approximately equal to the width of the surf zone, which
depends on the incident waves, principally the breaking wave height.

118. In GENESIS, the sand bypassing algorithm requires a depth of
active longshore transport, which is directly related to the width of the surf
under the assumption that the profile is a monotonically increasing function
of distance offshore, as discussed in the next section. In Version 2 of
GENESIS, a quantity called "the depth of active longshore transport," D,;, is
defined and set equal to the depth of breaking of the highest one-tenth waves
at the updrift side of the structure. Under standard assumptions, this depth

is related to the significant wave height H,,;; used throughout GENESIS, by

1.27
Dur = 7 (Hy/3)p )

1.27 = conversion factor between one-tenth highest wave height and
significant wave height

y = breaker index, ratio of wave height to water depth at breaking
(H,/3)) = significant wave height at breaking
If y= 0.78 is used in Equation 4, then D,7 ~ 1.6(Hj,;3), . The depth defin-
ing the seaward extent of the zone of active longshore transport D,; is much
less than the depth of closure Dc , except under extremely high waves.
119. GENESIS uses another characteristic depth, termed the "maximum
depth of longshore transport" D,7, to calculate the average beach slope

tanB appearing in Equation 2. The quantity D,,, is calculated as

Hy
Dito = (2.3 - 10.9H,) —— (5)
Lo
where
H,/L, = wave steepness in deep water

H, = significant wave height in deep water
L, = wavelength in deep water
The deepwater wavelength is calculated from linear wave theory as

L, = gT?7/2x , in which g is the acceleration due to gravity, and T is the

wave period. If spectral wave information is given, T is taken as the peak
spectral wave period; otherwise, it is the period associated with the signifi-
cant waves. Equation 5 was introduced by Hallermeier (1983) to estimate an
approximate annual limit depth of the littoral zone under extreme waves. In
the framework of GENESIS, D,;, is calculated at each time step from the
deepwater wave data and is assumed to be valid over the entire longshore
extent of the modeled reach. Since wave characteristics vary seasonally, this
definition of the maximum depth of longshore transport will reflect changes in

average profile shape and beach slope, as described next.

Average profile shape and slope

120. The shoreline change equation does not require specification of
the bottom profile shape since it is assumed that the profile moves parallel
to itself. However, to determine the location of breaking waves alongshore
and to calculate the average nearshore bottom slope used in the longshore
transport equation, a profile shape must be specified. For this purpose, the
equilibrium profile shape deduced by Bruun (1954) and Dean (1977) is used.
They demonstrated that the average profile shape for a wide variety of beaches

can in general be represented by the simple mathematical function

D = ay?2/3 (6)

in which D is the water depth, and A is an empirical scale parameter. The
scale parameter A has been shown by Moore (1982) to depend on the beach
grain size. For use in GENESIS, the design curve for A_ given by Moore was

approximated by a series of lines given as a function of the median nearshore

beach grain size ds, (ds) expressed in mm and units of A of m’/3):
Ay = OR41' (dc, )e 8? a Nvelen << Oath
A = 0..23(de,) 022 Hm ORG <denn< lOO
(7)
On 3 1(den)inas > 10.0: < ds, < 40.0
Avi=ON46: (den e244 a GO sOn aden

If beach survey profiles for the target beach are available, it is recommended
that the modeler use the curves in Figure 7 as templates to determine an
effective median grain size. The effective grain size, if supplied to
GENESIS, will produce an A-value that will give the most representative
profile shape. If profile survey data are lacking, the median grain size of
the surf zone sand should be used.

121. The average nearshore slope tanf for the equilibrium profile
defined by Equation 6 is calculated as the average value of the integral of
the slope @4D/dy from 0 to y,7 , resulting in tanf = A(y,;)\/? , in which
Ytr is the width of the littoral zone, extending seaward to the depth Dy, .

Since by definition, y,7 = (D,7,/A)°/? , the average slope is calculated to be

tanB = [ A ] (8)

Depth of closure
122. The depth of closure, the seaward limit beyond which the profile

does not exhibit significant change in depth, is a difficult parameter to
quantify. Empirically, the location of profile closure D, cannot be iden-
tified with confidence, as small bathymetric change in deeper water is
extremely difficult to measure. This situation usually results in a depth of
closure located within a wide range of values, requiring judgment to be
exercised to specify a single value. Often profile surveys are not available
to a sufficient depth and with sufficient vertical and horizontal control to
allow comparisons of profiles to be made. Figure 8a shows the standard devia-
tion of depth values from five wide-scale bathymetric surveys plotted as a
function of mean depth for Oarai, a Pacific Ocean beach in Japan (Kraus and
Harikai 1983). Figure 8b shows a similar plot composed of data from multiple
profile surveys made over a 4-year period along nine transects at Oceanside,
California. Changes in the profile fall off at a depth of about 6 m for the
case of Oarai and at about 30 ft National Geodetic Vertical Datum (NGVD) for
the case of Oceanside. These values were used as the depths of closure in the

respective shoreline response models.

5/7

et ct tk Ob 6 8 Z 9 S 14 € C L 0
0c'0 $c'0 Lok ae) Ov'0 OS'O0 OOF OD?
S$t°O ~_
(ww) 9Sp

(penutjuo9) ezts utTei3 pues eATIOeFJO eYyQ oUTMAZeQep 09 aeQeTdmey “/ eAN3Ty

sqtun o1r20W 2

(Spaipuny ‘w) e10Y4sjjO soue\sSIG

(wi) UoI}eAa|y

GL’O

(ww) OSp

(pepnqtoucj) “/ ean3Ty

sj tun Azeuwojsno ueoTisuy “q

(SpUBSNOY} ‘}}) B1OYSJJO BOURISIG
Ge € Gd vA ona L one) 0

02°00 S20 0£'0 Ov'O OS'O OO'L 00'S?

Oc -

Sl -

Ol-

(}) UOIBASIF

No. of data points
= 1660

Standard Deviation (m)

Depth (m)

a. Depth changes at Oarai Beach, Japan

Standard Deviation of Depth (ft—NGVD)

Mean Depth (ft—NGVD)

b. Depth Changes at Oceanside, California

Figure 8. Empirical determination of the depth of closure

123. Alternatively, the depth of closure may be estimated by reference
to a maximum seasonal or annual wave height. Hallermeier (1983) found that
the maximum seaward limit of the littoral zone could be expressed by
Equation 5 if the wave height and period are given by the averages of the
highest significant waves occurring for 12 hr during the year.

124. Since the depth of closure is difficult to estimate at most sites,
the modeler must use some external means to determine a value for the par-
ticular project. It is recommended that both bathymetry (profile) surveys and
Equation 5 be used as a check of the consistency of values obtained. On an
open-ocean coast, the depth of closure is not expected to show significant
longshore variation, since the wave climate and sand characteristics would be
similar. However, in the lee of large structures such as long harbor jetties
and breakwaters, the wave climate is milder due to sheltering, and the depth
of closure should be smaller. This effect is not accounted for in GENESIS,

which uses an average closure depth for the entire modeled reach.

Wave Calculation

125. Offshore wave information can be obtained from either a
"numerical" gage, i.e., a hindcast calculation, or from an actual wave gage.
Wave data are input to the model at a fixed time interval, typically in the
range of 6 to 24 hr. The wave height and direction at the gage must be trans-
formed to breaking at intervals alongshore for input to GENESIS. Monochro-
matic wave models hold the wave period constant in this process.

126. The modeling system GENESIS is composed of two major submodels.
One submodel calculates the longshore sand transport rate and shoreline
change. The other submodel is a wave model that calculates, under simplified
conditions, breaking wave height and angle alongshore as determined from wave
information given at a reference depth offshore. This submodel is called the
internal wave transformation model, as opposed to another, completely indepen-

dent, external wave transformation model which can be optionally used to

supply nearshore wave information to GENESIS. The availability and reliabil-
ity of wave data as well as the complexity of the nearshore bathymetry should

be used to evaluate which wave model to apply.

127. Use of the internal and external wave transformation models is
depicted in Figure 9. The internal model is applicable to a sea bottom with
approximately straight and parallel contours, and breaker height and angle are
calculated at grid points alongshore starting from the reference depth of the
offshore wave input (Figure 9a). If an external wave model is used
(Figure 9b), it calculates wave transformation over the actual (irregular)
bathymetry starting at the offshore reference depth. Resultant values of wave
height and direction at depths alongshore for which wave breaking has not yet
occurred are placed in a file (by the modeler) for input to the internal wave
model. These depths, taken, for example, as the depths in each wave calcula-
tion cell immediately outside the 6-m contour, define a "nearshore reference
line," from which the internal wave model in GENESIS takes over grid cell by
grid cell to bring the waves to the breaking point. If structures that
produce diffraction are located in the modeling reach, the internal model will
automatically include the effect of diffraction in the process of determining

breaking wave characteristics.

Internal Wave Transformation Model

Breaking waves

128. Wave transformation from the deepwater reference depth or the
nearshore reference line (depending on whether or not the external wave model
is used) is initially done without accounting for diffraction from structures
or landmasses located in the model reach. The solution strategy is to obtain
a first approximation without including diffraction and then modify the result
by accounting for changes to the wave field by each diffraction source.

129. Omitting diffraction, there are three unknowns in the breaking
wave calculation: the wave height, wave angle, and depth at breaking. Three
equations are needed to obtain these quantities. These are the equation for
the breaking wave height based on reference wave data (Equation 9), a depth-
limited breaking criterion (Equation 14), and a wave refraction equation

(Equation 16).

DEEPWATER REFERENCE DEPTH

y Vie
Lu
es \
= WAVE ayia
7) RAYS =
LL Yr>s>
ro) LOCALLY STRAIGHT AND er
bl PARALLEL BOTTOM CONTOURS ne
INS L]
il.
7)
2 \ Died
BREAKER LINE SHORELINE
DISTANCE ALONGSHORE x
a. Transformation by internal wave model only
Val DEEPWATER REFERENCE DEPTH
Y/
Ld
aS Ea
se ra
ie [e)
ie IRREGULAR BOTTOM =
Oo y
a NEARSHORE <
9 REFERENCE
z LINE
n INTERNAL
a WAVE. MODEL

BREAKER LINE

SHORELINE

DISTANCE ALONGSHORE

b. Transformation by external and internal wave models

Figure 9. Operation of wave transformation models

130. Equation 9 is used to calculate the height of breaking waves that

have been transformed by refraction and shoaling (Figure 10):
Hz = KpksHre¢ (9)

where
H, = breaking wave height at an arbitrary point alongshore
Kg = refraction coefficient
Kg = shoaling coefficient

H = wave height at the offshore reference depth or the nearshore
reference line depending on which wave model is used

131. The refraction coefficient Kg is a function of the starting
angle of the ray and the angle of arrival at P, , the location of which is

determined by the breaking depth. Kg is given by

Costa 7

cos6,

in which 6, is the angle of the breaking wave at P, .
132. The shoaling coefficient Kg, is a function of the wave period,

the depth at P, , and the breaker depth and is given by:

[=]
ie || = (11)

in which C,, and C,, are the wave group speeds at P, and the initial

break point, respectively. The group speed is defined as
Chiron (12)

where

C = wave phase speed = L/T

L = wavelength at the depth D
0.5[1 + (2xD/L)/sinh(2nD/L) ]

5
ll

133. The wavelength is calculated from the dispersion relation,

Teme tanh[272 (13)

L
To minimize computer execution time, a rational approximation (Hunt 1979) with

an accuracy of 0.1 percent is used to solve the transcendental Equation 13.

134. The equation for depth-limited wave breaking is given by
H, = 7D, (14)

in which D, is the depth at breaking and the breaker index y is a function
of the deepwater wave steepness and the average beach slope (Smith and Kraus,

in preparation):

Ho
y=b-a— 5)

L,
in which a = 5.00 [1 - exp(-43 tan8)] and b =1.12/[1 + exp(-60 tanf)].

135. The wave angle at breaking is calculated by means of Snell's law,

sind, im sind, (16)
Ly Ly

in which 6, and I, are the angle and wavelength at the break point, and

6, and L, are the corresponding quantities at an offshore point.

136. The three unknowns, H, , D, , and 6, , are obtained at inter-
vals alongshore by iterative solution of Equations 9, 14, and 16 as a function
of the wave height and angle at the reference depth and the wave period.

137. Wave refraction models provide the undiffracted breaking wave
angle 96, in the fixed coordinate system. With reference to Figure 10, the
breaking wave angle to the shoreline required to calculate the longshore sand

transport rate, Equation 2, is obtained as

in which §@, = tan ‘(dy/dx) is the angle of the shoreline with respect to the

x-axis. In GENESIS, an angle of 0 deg signifies shore-normal wave incidence.

The angle 06, drawn in Figure 10 is positive.

y
WJ

= @, ANGLE_OF INCIDENT WAVE
ea b CREST TO THE X-AXIS
[e)

* "+ DISTANCE ALONGSHORE

Figure 10. Definition of breaking wave angles

138. If there are no structures to produce diffraction, the undif-
fracted wave characteristics are used as input to the sediment transport
relation (Equation 2). If such obstacles are present, breaking wave heights

and directions are recalculated, as described next.

Breaking waves affected by structures
139. Structures such as detached breakwaters, jetties, and groins that

extend well seaward of the surf zone intercept the incident waves prior to
breaking. Headlands and islands may also intercept waves. In the following
discussion, all such objects are referred to as structures. Each tip of a
structure will produce a near-circular wave pattern, and this distortion of
the wave field is a significant factor controlling the response of the
shoreline in the lee of the structure. Sand typically accumulates in the
diffraction shadow of a structure, being transported from one or both sides by
the oblique wave angles in the circular wave pattern and the decrease in wave

height alongshore with penetration into the shadow region. Accurate and

efficient calculation of waves transforming under combined diffraction,
refraction, and shoaling to break is required to obtain realistic predictions
of shoreline change in such situations.

140. Figure 11 is a definition sketch of the calculation procedure for
the breaking wave height and angle behind a structure (Kraus 1981, 1982,
1984). Conceptually, the area of interest is separated into a shadow region
and an illuminated region by a wave ray directed toward the beach from the tip
of the structure at the same angle as the incident waves arriving at the tip.
To determine the breaking wave height, a diffraction coefficient must be
calculated in both regions because the diffraction effect can extend far into
the illuminated region. To determine the breaking wave angle, inside the
shadow region, wave rays are assumed to proceed radially from the tip of the
structure P, at an angle 9§, to arrive at some point P, , where they
break.

141. The angle 9, at which a wave ray must start to arrive at P,
inside the shadow region is not known a priori since it is a function of the
breaking criterion as well as the distance alongshore defining the location of
grid cells in the numerical calculation. A ray shooting technique can be used
to determine 96, (Kraus 1982, 1984), but this procedure is complex and
requires considerable execution time. As an approximation, the geometric
angle 9, defined by the straight line between P, and P, is used.

142. In areas affected by diffraction, Equation 18 is used to calculate
the height of breaking waves that have been transformed by diffraction,

refraction, and shoaling

H, = Kp(@p,D,)Hy, (18)

where

Kp = diffraction coefficient

>
0
|

= angle between incident wave ray at P, and straight line
between P, and P, , if P, is in the shadow region

Hy = breaking wave height at the same cell without diffraction
The diffraction, refraction, shoaling coefficients are also functions of the
depth at P, and the wave period, but these quantities are known and, there-

fore, not included in the function arguments in Equation 18.

143. The three unknowns, H, , Dy , and 6, , are obtained at intervals
alongshore by iterative solution of Equation 18 together with Equations 14 and

16 as a function of wave height and angle at the breaking depth and period.

INCIDENT WAVE
DIRECTION |

BREAKWATER \ \

ILLUMINATED
REGION

DISTANCE OFFSHORE

SHADOW
REGION

X2 x4 x
DISTANCE ALONGSHORE

Figure 11. Definition sketch for wave calculation

144. Diagrams that give contours of the diffraction coefficient for
monochromatic waves (in uniform water depth) can be found, for example, in
Chapter 2 of the SPM (1984). In these diagrams, the value of the diffraction
coefficient along the line of wave incidence defining the shadow and illumi-
nated regions is about 0.5, indicating that the wave height is about 50
percent reduced along this line. However, for the field situation of sea
waves having a spread about the principal direction of incidence, the reduc-
tion in wave height is not expected to be as great as for monochromatic waves.
Goda, Takayama, and Suzuki (1978) developed methods for calculating diffrac-

tion of random waves as caused by large land masses based on the concept of

directional spreading of waves and penetration of energy to the lee of a land
mass or long structure. Their results show that the value of the diffraction
coefficient along the separation line is about 0.7.

145. Because GENESIS was developed to simulate waves and shoreline
change in the field, the procedure of Goda, Takayama, and Suzuki (1978) (see
also, Goda (1984)) was adapted. Details of application of the method to
calculate wave breaking produced by combined diffraction, refraction, and
shoaling as used in GENESIS are given by Kraus (1981, 1982, 1984, 1988a). In
GENESIS it is assumed that the method is valid for relatively short structures

such as detached breakwaters.

Contour modification

146. The beach plan shape changes as a result of spatial differences in
longshore sand transport. The change in the beach shape, in turn, alters the
refraction of the waves. Within the framework of the wave model internal to
GENESIS, the interaction between the beach and waves is accounted for in two
ways. First, with change in position of the shoreline, the distance to the
source of refraction (P, in Figure 12) will change, and hence the ray start-
ing angle 96, will also change. Second, the shape of the shoreline will
distort in the vicinity of a structure, and the offshore contours will tend to
align with this shape. This effect is accounted for by assuming that the
orientation of the shoreline at a particular point extends to the depth where
the diffraction source or reference depth is located. Thus, although plane
and parallel contours are assumed, their orientation is allowed to change as a
function of position alongshore to conform with the local beach plan shape.

147. Such a local coordinate system aligned with the local contours is
defined by the (x’, y’) axes in Figure 12. This coordinate system is rotated

by the angle of orientation of the local shoreline 6, = tan ‘(dy/dx) eval-

s
uated at point P, . In the rotated coordinate system, an angle 0’ is
related to the angle @ in the fixed (original) system by 0’ = 6+ 6, .
Equation 16 can be used to calculate wave refraction in the primed coordinate
system but with angles on both sides replaced by corresponding primed wave

angles. Similarly, the refraction coefficient (Equation 10) can be calculated

using primed wave angles. After the wave angle and wave transformation are
calculated in the rotated system, the breaking wave angle is converted back to
the fixed coordinate system for use in the longshore sand transport rate
equation (Equation 2). Thus, in the shadow region, the breaking wave height

is calculated as

Hy = Kp(8p,Dp)KR(O1,D,) Hp (19)

in which Kp = refraction coefficient in the primed (rotated) coordinate
system. Use of this contour modification technique significantly improves the
accuracy of the internal wave model by giving a more realistic value of the
breaking wave angle (Kraus 1983, Kraus and Harikai 1983). The contour
modification is calculated automatically by the internal wave model in GENESIS

in taking waves from a reference depth to the point of breaking.

INCIDENT WAVE
DIRECTION

BREAKWATER

DISTANCE OFFSHORE

Ssoenraue LINE

fig

x2 x4 x
DISTANCE ALONGSHORE

Figure 12. Wave angles in contour modification

Wave transmission at detached breakwaters

148. The design of detached breakwaters for shore protection requires
consideration of many factors, including structure length, distance offshore,
crest height, core composition, and gap between structures in the case of
segmented breakwaters. Several studies (Perlin 1979; Kraus 1983; Kraus,
Hanson, and Harikai 1984; Hanson 1989) have described numerical simulations of
the influence of detached breakwaters on the shoreline. However, an important
process absent in these works was wave transmission at the breakwaters. Wave
transmission, referring to the movement of waves over and through a structure,
is present in most practical applications, since it is economical and often
advantageous from the perspective of beach change control to build low or
porous structures to allow energy to penetrate behind them.

149. One of the principal upgrades of Version 2 of GENESIS over the
previous version of the modeling system is the capability to simulate wave
transmission at detached breakwaters and its impact on shoreline change. This
capability was tested with excellent results for Holly Beach, Louisiana, a
site containing six breakwaters of different construction and transmission
characteristics (Hanson, Kraus, and Nakashima 1989).

150. In order to describe wave transmission in the modeling system, a
value of a transmission coefficient K, must be provided for each detached
breakwater. The transmission coefficient, defined as the ratio of the height
of the incident waves directly shoreward of the breakwater to the height
directly seaward of the breakwater, has the range O < K,; < 1 , for which a
value of O implies no transmission and 1 implies complete transmission.

151. The derivation of the phenomenological wave transmission algorithm
in GENESIS was developed on the basis of three criteria:

a. As Ky approaches zero, the calculated wave diffraction
should equal that given by standard diffraction theory for an
impermeable, infinitely high breakwater.

b. If two adjacent energy windows have the same K, , no diffrac-
tion should occur (wave height uniform at the boundary).
c¢. On the boundary between energy windows with different Kk, ,

wave energy should be conveyed from the window with higher
waves into the window with smaller waves. The wave energy
transferred should be proportional to the ratio between the
two transmission coefficients.

152. The criteria lead to the following expression for the diffraction

coefficient Kp; for transmissive breakwaters:

Reick Reel 0K) ass

in which Ry, is the ratio of the smaller valued transmission coefficient to
the larger valued transmission coefficient for two adjacent breakwaters.

153. Figure 13 shows a hypothetical example of shoreline change behind
a transmissive detached breakwater. The breakwater is 200 m long and located
250 m offshore. Incident waves with T = 6 sec and H=1.5 m propagate with
the wave crests parallel to the initially straight shoreline, and the simula-
tion time is 180 hr. As expected, the seaward extent of the induced large
cusp (salient) decreases as wave transmission increases. Also, the salient
broadens slightly with increased transmission, and the eroded areas on either

side of the salient fill in.

Shoreline position (m)

ZEZGZS LDL DADA DLGLPLILDA Wave] Crests

@) 100 200 300 400 500
Distance alongshore (m)

Figure 13. Shoreline change as a function of transmission

Representative offshore contour
154. A basic assumption in the formulation of the shoreline change

model is that the profile moves parallel to itself. As a consequence,
offshore contours move parallel to the shoreline. If this assumption is
applied directly in the internal wave model, unrealistic wave transformation
can result in regions where the shoreline position changes relatively abrupt-
ly, possibly leading to numerical instability. To overcome this limitation,
GENESIS has the option of using a smoothed offshore contour in performing the
internal wave calculation, as illustrated in Figure 14. In this figure, the
shore-parallel contour shown changes radically at the groin. The smoothed
contour is expected to better represent the offshore bathymetry. If the
smoothed contour option is chosen, the contour is assumed to be representative
for all contour lines between the input wave depth and the undiffracted wave
breaking depth. The orientation of the representative offshore contour is

recalculated on monthly intervals using the shoreline position at that time.

SHORELINE—PARALLEL
ue GN < OFFSHORE CONTOUR

ee ee ee
oe
SS (oS ee

oS BS a2
SMOOTHED

OFFSHORE CONTOUR

SHORELINE

Figure 14. Example of representative contour

ie)

External Wave Transformation Model: _RCPWAVE

155. In many applications offshore contours cannot be considered as
plane and parallel. In these cases accurate modeling of shoreline change
requires calculation of the nearshore waves using the actual bathymetry. For
the open-coast situation, the linear wave transformation model RCPWAVE
(Ebersole 1985; Ebersole, Cialone, and Prater 1985) has advantages for use

with GENESIS:

a. It solves for wave height and angle values directly on a grid.

b. It is efficient, allowing wide-area coverage.

c. It includes diffractive effects produced by an irregular
bottom, thus reducing caustic generation as well as providing
better accuracy than a pure refraction model.

d. It has proven to be very stable.

156. RCPWAVE places values of wave height and direction at grid points
on a nearshore reference line, shown schematically in Figure 9b. From this
line the internal wave transformation model in GENESIS brings waves to
breaking. Figure 15 shows GENESIS and RCPWAVE in the overall calculation
flow.

157. Shoreline change simulation intervals are typically on the order
of several years, and the extent of the modeled reach several kilometers,
requiring hundreds of grid cells. Since the time step for the simulation is
typically 6, 12, or 24 hr, thousands of wave calculations must be performed.
It is impractical to run a wave transformation model such as RCPWAVE for each
time step because of the enormous execution time involved. A general wave
model runs on a two-dimensional grid, and its execution time is proportional
to N* , where N is on the order of the number of grid cells in the x- and
y-directions. In contrast, GENESIS is a one-dimensional model, and its
execution time is proportional to N . Therefore, it is unbalanced in
computational effort to perform a general wave calculation at every shoreline
simulation time step. As a related physical consideration, time series of
offshore waves are usually not available or, if available, contain uncertain-
ties, implying that an expensive, accurate numerical wave transformation

calculation would not be in balance with approximate input data.

OFFSHORE WAVES BATHYMETRIC DATA

Ho, Qo, T

RCPWAVE
(External Wave Model)

REFERENCE WAVES
AipnOm ok

REFERENCE DEPTHS

(Internal Wave Model)

HISTORICAL SHORELINE STRUCTURES, BOUNDARY
POSITIONS G ENESIS CONDITIONS, OTHER DATA

SI ave MIDVES LONGSHORE TRANSPORT RATE
Hpi, Obi, Ui ;

(Internal Wave Model) Qi

SHORELINE CHANGE
Ay

Figure 15. GENESIS, RCPWAVE, and the overall calculation flow

158. Rather than running the external wave model at every time step, a
time savings technique is used in which the offshore wave conditions are
divided into period and direction bands (Kraus et al. 1988). Typically, the
range in period existing in the record is divided into l-sec intervals, and
the range in direction of incident waves is divided into 11.25- or 22.5-deg
intervals. This procedure gives on the order of 50 to 100 period-direction
bands, and refraction runs are made with the external wave model using unit
wave height to provide what are termed "transformation coefficients" along the

nearshore reference line. To key into these calculated refraction results,

the wave conditions in the offshore time series are grouped into the desig-
nated period-direction bands. The wave height on the nearshore reference line
calculated with unit offshore wave height is then given as the product of the
transformation coefficient alongshore and the input offshore wave height at
the time step, which is permissible by linear wave theory. Thus, although the
wave period and direction are constrained to lie in a finite number of bands,
the actual offshore wave height is used. Since it is doubtful whether
directional resolution greater than 11.25 or 22.5 deg can be achieved by
either a deepwater wave gage or hindcast, the described procedure is an
adequate representation of the data, yet it allows for efficient calculation.
Smaller increments in wave angle could be implemented, if appropriate.

159. As an alternative to building a key for accessing the refraction
results, nearshore wave conditions on the reference line thus calculated can
be arranged in their order of occurrence in the offshore wave time series and
a large data file of nearshore wave conditions generated and stored for input.
In any case, manipulation of the wave data base requires substantial effort
and is one of the necessary tasks that must be performed as part of the data
preparation process if an external wave model is used. Practical details of
the use of an external refraction model with GENESIS are given in the GENESIS
Workbook.

Limiting Deepwater Wave Steepness

160. The input offshore wave data may be changed or manipulated for a
number of reasons, for example, to examine model sensitivity, to look at
extreme cases, and to run waves for storm (high-wave) conditions. In these
investigations the wave height is usually increased. In the process, if care
is not taken, it is possible to specify waves of unphysically large steepness.
GENESIS performs a check that the offshore input wave steepness satisfies the

Mitchell (1893) limiting wave steepness criterion:

Tae 0.142 (21)

If the calculated wave steepness exceeds the value of 0.142, the deepwater
wave height is reduced to satisfy Equation 21, maintaining input wave period

at the same value. A warning message is also issued.

Wave Energy Windows

161. The concept of wave energy windows is central to GENESIS and
determines its algorithmic structure. Wave energy windows provide a powerful
means of describing breaking wave conditions alongshore and the associated

sand transport for a wide variety of configurations of coastal structures.

Energy windows

162. An energy window is an area open to incident waves as viewed from
a particular stretch of beach. Operationally, an energy window is defined by
two boundaries that are regarded as limiting the penetration of waves to the
target beach. Windows are separated by diffracting jetties, diffracting
groins, nontransmissive detached breakwaters, and the tips of transmissive
detached breakwaters. (The term "transmission" refers to the transmission of
waves through or over a detached breakwater.) Incident wave energy must enter
through one of these windows to reach a location in the nearshore area. It is
possible (and common) for a location to be open to waves from more than one

window.

Sand transport calculation domains

163. At the present stage of model development, shore-connected struc-
tures (jetties, groins, and breakwaters) are assumed not to transmit wave
energy, so that waves entering on one side of such a structure cannot propa-
gate to the other side. Based on the concept of wave energy windows and non-
wave transmissibility of shore-connected structures, the shoreline is divided
into what are called "sand transport calculation domains." These domains
consist of segments of the coast bounded on each side by either a diffracting
shore-connected structure or a model boundary. GENESIS solves the shoreline
change equation independently for each domain, except for conditions such as
sand passing around or through groins, which allow exchange of sand across the

boundaries of the calculation domains.

Examples
164. Examples of wave energy windows and transport calculation domains

for a hypothetical modeling project are given in Figure 16. In this and
similar figures, a diffracting tip of a structure is indicated by emanating
circular wavelets; nondiffracting tips of structures have no wavelets.
Structures allowing wave transmission are also indicated by emanating wave-
lets. The vertical scale on this figure is greatly exaggerated. The energy

windows are labeled by E1-E5 and the structures by S1-S6.

S6
CG

DISTANCE OFFSHORE

GRID
BOUNDARY

Figure 16. Energy windows and transport calculation domains

El: This semi-infinite window is bounded only on the right side, the-
open sea being on the left side. Waves entering though El are diffracted by
the left tip of structure $1. Waves entering through this window (or through
window E2) cannot arrive at beaches to the right of structure S3 and, there-
fore, do not directly generate sand transport to the right of S3. Sand
bypassing from left to right at S3 can occur, supplying a boundary condition

to the transport domain defined by the region between S3 and S4.

Sl: This detached breakwater has two diffracting tips, the left tip
defining the right boundary of window El and the right tip defining the left
boundary of window E2. The detached breakwater is nontransmissive and,
therefore, not itself an energy window.

S2: The structure $2, a short groin, does not define an energy window
since it does not produce diffraction; similarly, it does not define the
boundary of a sand transport calculation domain but is merely located inside
the transport domain extending from the left boundary of the grid to S3.

E2: This window is bounded by diffracting structures Sl and S3. Waves
entering through this window can reach to the left boundary of the grid but
cannot reach the beach segments to the right of S3. Window E2 is thus located
inside the same transport domain as window El, the transport domain defined by
an open boundary on the left and tip S3 on the right.

S3: Because longshore sand transport is produced by breaking waves,
only groins extending through the surf zone are considered to influence wave
breaking by diffraction. The effect of shorter groins is confined to con-
straining the sand transport rate. In this example S3 is considered to be
diffracting, and waves entering past one side of the structure cannot propa-
gate to the other side. Structure S3 thus defines a boundary of a sand
transport calculation domain.

E3: Waves entering through this energy window cannot propagate into the
area on the left side of structure S3 or to the right of structures S4-S5.

$4 and $5: In GENESIS the two basic structure elements, the groin and
one or more detached breakwaters, can be combined to create T-groins, half-Y
groins, spur jetties, or even more complex configurations. Because S4 is
connected to a detached breakwater, it must be regarded as being diffracting
and, thus, also acts as a boundary of a sand transport calculation domain.

E4: In this example the structure segment S5 allows wave transmission,
and waves arriving at the structure will pass through it but have diminished
height. As a result, the structure S5 is also regarded as an energy window.

E5: Waves entering through this window can reach the right boundary of
the grid, but cannot reach the beach segments to the left of S4.

S6: If the wave energy entering the project area from the right side of

structure S6 can be neglected, the structure can be assumed to be infinitely

long. Then shoreline change to the right of S4-S5 is governed solely by wave
energy entering through windows E4 and E5.

165. GENESIS will perform the shoreline calculation for the hypotheti-
cal project shown in Figure 16 by separating it into three sand transport
domains: the beach from the left boundary to structure $3, the beach between
structures $3 and S4-S5, and the beach from S4-S5 to the right boundary. Wave
energy windows, breaking waves, and longshore sand transport rates are
determined automatically by GENESIS for the three domains on the basis of the

input data.

Multiple diffraction
166. If an energy window is bounded by two sources of wave diffraction,

one on the left (L) and one on the right (R), each will have an associated
diffraction coefficient, Kp, and Kpg , respectively. The internal wave

model calculates a combined diffraction coefficient K) for the window as

Kp = Kp.Kpr (22)

as shown in Figure 17. If an energy window is open on one side, the diffrac-

tion coefficient for that side is set equal to 1.0.

DISTANCE ALONGSHORE

Figure 17. Diffraction coefficient for two sources

Numerical Solution Scheme

167. If all information is available to use Equation 1 (shoreline
change equation), Equation 2 (longshore sand transport rate equation), and
Equation 14 (wave breaking criterion), the response of the shoreline to wave
action can be calculated. Under certain simplified conditions, closed-form
mathematical solutions of Equation 1 can be found (see, for example, Larson,
Hanson, and Kraus 1987), but in order to describe realistic structure and :
shoreline configurations, including waves that vary alongshore and with time,
Equation 1 must be solved numerically. In a numerical solution procedure, the
distance alongshore is divided into cells of a certain width (called the grid
spacing), and the duration of the simulation is similarly divided into small
elements (called the time step). If the grid spacing and time step are small,
solutions of the governing partial differential equation (Equation 1) can be

accurately calculated by numerical solution of the finite-difference equation.

Numerical and physical accuracy

168. Referring to Figure 6 and the shoreline change equation
(Equation 1), the change in position of the shoreline can be mathematically

written as

2): ube Ci fag (AQ)
Se a2 A (DEEERDA VAR

(23)
in which AQ is the difference in longshore sand transport rates at the walls
of the cell. In arriving at Equation 23, the contribution to Ay by line
sources and sinks q was omitted for simplicity. Equation 23 indicates that
the change in shoreline position Ay is directly proportional to At and
inversely proportional to Ax (actually, Ay is inversely proportional to
(Ax)? , as described below).

169. Numerical accuracy refers to the degree to which the numerical
scheme provides an accurate solution to the partial differential equation
(Equation 1). Physical accuracy refers to the degree to which Equation 1 and
the associated input data represent the actually occurring processes.

Physical accuracy depends on the quality of the input data and the degree to

which the basic assumptions of shoreline change modeling approximate condi-
tions at the site. Good numerical accuracy does not necessarily imply good
physical accuracy. For a rapid numerical solution, the time step should be as
large as possible. On the other hand, the numerical and physical accuracy
will obviously be improved if the time step is small, since changes in the
wave conditions and changes in the shoreline position itself (which feed back
to modify the breaking waves) will be better represented. Similarly, use of
many small grid cells will provide more detail or improved numerical accuracy
in the shoreline change calculation than use of fewer but longer cells, but

the calculation time will increase as the number of cells increases.

Numerical stability

170. The allowable grid spacing and time step of a finite difference
numerical solution of a partial differential equation such as Equation 1
depend on the type of solution scheme. Under certain idealized conditions,
Equation 1 can be reduced to a simpler form to examine the dependence of the
solution on the time and space steps. The main assumption needed is that the
angle 6,, in Equation 2 is small. In this case, sin26,, = 26,, . By Equa-
tion 17, 6,, = 6, - dy/dx , since the inverse tangent can be replaced by its
argument if the argument is small. The derivative of Q with respect to x
is required (Equation 1 or Equation 23) and, under the small-angle approxima-
tion, 0Q/dx ~ 4(26,,)/dx ~ 28*y/ax? , if it is assumed that 6, does not
change with x. After some algebraic manipulation, Equation 1 (or Equation
23 rewritten as a partial differential equation) can be expressed as (Kraus

and Harikai 1983):

2
dt ax2
where
2K,
“yay ben’ ila alae 2
Tae DSEREDANIE GE.” oe)

and

K2
ier he aD ai a2 OH
€2 = (DNEFEDS) E C, cos6,, an (26)

As Equation 24 is a diffusion-type equation, its stability properties are well

known. The numerical stability of the calculation scheme is governed by:

At(e, + €2)
Peep eae (27)
(Ax)?

The quantity Rg, is known as the Courant number in numerical methods; here it
is called the stability parameter. The finite difference form of Equation 24
shows that Ay ~ At/(Ax)? .

171. Equation 24 can be solved by either an explicit or an implicit
solution scheme. If solved using an explicit scheme, the new shoreline
position for each of the calculation cells depends only on values calculated
at the previous time step. The main advantages of the explicit scheme are
easy programming, simple expression of boundary conditions, and shorter
computer run time for a single time step as compared with the implicit scheme.
A major disadvantage is, however, preservation of stability of the solution,
imposing a severe constraint on the longest possible calculation time step for
given values on model constants and parameters. If an explicit solution
scheme is used to solve the diffusion equation, the following condition must

be satisfied (Crank 1975):
Rg < 0.5 (28)

172. If an explicit solution scheme is used and the value of R,
exceeds 0.5 at any point on the grid, the calculated shoreline will show an
unphysical oscillation that will grow in time if R, remains above 0.5,
alternating in direction at each grid point. The quantities ¢, and e€, can
change greatly alongshore since they depend on the local wave conditions.

Assuming that the grid cell spacing is fixed by engineering requirements, a

large wave height would necessitate a small value of At . Although there are
calculation strategies to overcome this problem, it is inefficient to use an
explicit solution scheme to solve for shoreline position in a general case.

173. Equation 1, of which Equation 24 is a special case, can also be
solved using an implicit scheme in which the new shoreline position depends on
values calculated on the old, as well as the new, time step. The main
advantage of the implicit scheme is that it is stable for very large values of
Rs . The disadvantages of the implicit solution scheme are that the program,
boundary conditions, and constraints become more complex, as compared with the
explicit scheme. These disadvantages are, however, not considered to be
major.

174. An implicit solution scheme is used in GENESIS to solve Equa-
tion 1, as developed by Kraus and Harikai (1983) based on a method given by
Perlin and Dean (1978). Kraus and Harikai also showed for a specific example
that the magnitude of the stability parameter gives an indication of numerical
accuracy of the solution. Roughly speaking, for values of Rg, less than 10,
the numerical error equaled the magnitude of R, expressed as a percentage.
Above the value of 10, the error increased at a greater than linear rate with
Rg . GENESIS calculates the value of Rg, at each time step at each grid
point alongshore and determines the maximum value. If Rg, > 5 for any grid
point, a warning is issued. The implicit finite difference scheme is dis-

cussed further below.

Grid System and Finite Difference Solution Scheme

Staggered grid
175. In GENESIS calculated quantities along the shoreline are dis-

cretized on a staggered grid in which shoreline positions y, are defined at
the center of the grid cells ("y-points") and transport rates Q, at the cell
walls ("Q-points"), as shown in Figure 18. The left boundary is located at
grid cell 1, and the right boundary is at cell N. In total there are N
values of the shoreline position, so the values of the initial shoreline
position must be given at N points. There are N+l values of the longshore

sand transport rate since N+l cell walls enclose the N cells; values of

the transport rate must be specified at the boundaries, Q, and Qy,, , and
the remainder of the Q,; and all y, will be calculated. Since the Q, are
a function of the wave conditions, all wave quantities are calculated at Q-
points. The tips of structures are likewise located at Q-points. Beach
fills, river discharges, and other sand sources and sinks are located at y-

points.

y
BOUNDARY
CONDITION
AT CELL WALL 1
CELL
WALL
ws i+1
a
2 BOUNDARY
i CONDITION
rs AT CELL WALL N+1
WW
2
b
a

CELL NO. 1 i i i x
DISTANCE ALONGSHORE/GRID CELL NUMBER

Figure 18. Finite difference staggered grid

Implicit finite difference solution scheme

176. In the following, a subscript i denotes a quantity located at an
arbitrary cell number i along the beach. A prime (') is used to denote a
quantity at the new time level, whereas an unprimed quantity indicates a value
at the present time step, which is known. The quantities y’ and Q’ are
not known and are being sought in the solution process; other primed quan-

tities such as q’ and D, refer to data at the next time step and are known.

177. The Crank-Nicholson implicit scheme is used (Crank 1975) in which
the derivative 4Q/dx at each grid point is expressed as an equally weighted

average between the present time step and the next time step:

1 | Qit2 - Qi Qitr - Qa
Sa Tl an Saal eae aaa (22)

Substitution of Equation 29 into Equation 1 and linearization of the wave
angles in Equation 2 in terms of dy/dx results in two systems of coupled

equations for the unknowns y; and Q;:

Nae De COI es OSE F aamaeh (30)

and

Qi = ENCyaaa = act Ea (31)

where
B’ = At/[2(Dg +D'c)Ax]
yc, = function of known quantities, including q’, and q;

E, = function of the wave height, wave angle, and other
known quantities

function similar to E,
178. The so-called double-sweep algorithm is used to solve Equations 30
and 31. Details of the solution procedure are given in Kraus and Harikai

(1983), Hanson (1987), Hanson and Kraus (1986b), and Kraus (1988c).

Lateral Boundary Conditions and Constraints

179. GENESIS requires specification of values for Q at both boun-
daries, cell walls 1 and N+l , at each time step. The importance of the
lateral boundary conditions cannot be overemphasized, as calculated shoreline
positions on the interior of the grid depend directly upon them. The most

ideal lateral boundaries are the terminal points of littoral cells, for

example, long headlands or long jetties at entrances and inlets. On the other
hand, engineering structures such as groins or seawalls may be present on the
internal domain of the grid. These barriers interrupt the movement of sand
alongshore and so constrain the transport rate and/or movement of the shore-
line. These constraints, which function similar to boundary conditions, must
be incorporated in the simulation. In the following, commonly used boundary

conditions are discussed.

Pinned-beach boundary condition
180. It is helpful to plot all available measured shoreline position

surveys together to determine locations along a beach that might be used as
model boundaries. In doing so it is sometimes possible to find a portion of
the beach distant from the project that does not move appreciably in time. By
locating the model boundary at such a section, the modeled lateral boundary
shoreline coordinate can be "pinned." Expressed in terms of the transport

rate, this means

Qi = ®& (32)

if implemented on the left boundary, and

Qut1 = Qn (33)

if implemented on the right boundary. These relations can be readily under-
stood by reference to Equation 23; if AQ =O at the boundary, then Ay =0 ,
indicating that y does not change. The pinned-beach boundary should be
located far away from the project to assure that the conditions in the
vicinity of the boundary are unaffected by changes that take place in the
project. Details of the mathematical representation of this boundary condi-

tion in the double sweep algorithm are presented in Hanson (1987).

Gated boundary condition
181. Groins, jetties, shore-connected breakwaters, and headlands that

interrupt, partially or completely, the movement of sand alongshore may be
incorporated as a boundary condition if one is located on an end of the

calculation grid. If located on the internal domain of the grid, these

objects will act to constrain the transport rate and shoreline change,
automatically calculated by GENESIS. The representation is the same for both
cases, although it occurs in different places in the numerical solution
scheme.

182. The effect of a groin, headland, or similar object located on the
boundary is formulated in terms of the amount of sand that can pass the struc-
ture. Consideration must be given to sand both entering and leaving the grid.
For example, at a jetty located next to an inlet with a deeply dredged
navigation channel, sand might leave the grid by bypassing the jetty during
times of high waves; in contrast, no sand is expected to cross the navigation
channel and jetty to come onto the grid. The jetty/channel thus acts as a
selective "gate," allowing sand to move off but not onto the grid. This
"gated boundary condition" was termed the "groin boundary condition" in
previous descriptions of GENESIS.

183. The most appropriate mathematical representation of the gated
boundary condition is a subject of active research (Gravens and Kraus 1989),
and GENESIS is expected to undergo revision in this capability. At present
two approaches are under study, one in which the amount passing the boundary
is proportional to the transport rate at the immediately updrift grid cell
(Perlin and Dean 1978) and the other in which the amount is proportional to
the potential longshore transport rate at the location of the boundary (Hanson
and Kraus 1980). In any case, the gating action on a boundary is controlled
by the combined actions of sand bypassing and sand transmission.

184. Sand bypassing. In GENESIS, two types of sand movement past a
structure are simulated. One type of movement is around the seaward end of
the structure, called bypassing, and the other is through and over the
structure, called sand transmission. Bypassing is assumed to take place if
the water depth at the tip of the structure Dg is less than the depth of
active longshore transport D,;, . Since the shape of the bottom profile is
known (Equation 6), Dg is determined from knowledge of the distance between
the tip of the structure and the location of the shoreline. However, since
structures are located at grid cell walls between two calculated shoreline

positions, this depth is not unique. In GENESIS the updrift depth is used.

185. To represent sand bypassing, a bypassing factor BYP is intro-

duced and defined as

(Des Dex) (34)

implying a uniform cross-shore distribution of the longshore sand transport
rate. If D, 2D; , BYP = 0. Values of BYP thus lie in the range

0 < BYP <1, with BYP = 0 signifying no bypassing, and BYP = 1 signifying
that all sand can potentially pass the position of the structure. The value
of BYP depends on the wave conditions at the given time step, since D,; is
a function of the wave height and period (Equation 4).

186. Sand transmission. A permeability factor PERM is analogously
introduced to describe sand transmission over, through, and landward of a
shore-connected structure such as a groin. A high (in relation to the mean
water level), structurally tight groin that extends far landward so as to
prevent landward sand bypassing is assigned PERM = 0 , whereas a completely
"transparent" structure is assigned the value PERM = 1. Values of PERM
thus lie in the range of O < PERM <1 and must be specified through judgment
of the modeler based upon, for example, the structural characteristics of the
groin (jetty, breakwater), its elevation, and the tidal range at the site.
Aerial photographs are often helpful in estimating a structure's amount of
void space (hence PERM) in relation to other structures on the model grid.

The optimal value of PERM for each structure must then be determined in the
process of model calibration.

187. With the values of BYP and PERM determined, GENESIS calculates
the total fraction F of sand passing over, around, or through a shore-

connected structure as (Hanson 1987)

F = PERM(1 - BYP) + BYP (35)

This fraction is calculated for each shore-connected (groin-type) structure

defined on or at the boundaries of the grid.

Seawall

188. A seawall, or, in general, any shore-parallel nonerodible barrier
such as a rocky cliff, imposes a constraint on the position of the shoreline
because the shoreline cannot move landward of the wall. Hanson and Kraus
(1985, 1986b) developed a procedure for calculating the position of the
shoreline constrained by a seawall. The procedure is consistent with shore-
line response modeling theory and has the following three properties:

The shoreline in front of a seawall cannot recede landward of
the wall.

Sand volume is conserved.

ce. The direction of longshore sand transport at the wall is the
same as that of the potential local transport.

GENESIS first calculates longshore sand transport rates along the beach based
on the assumption that the calculated amount of sand is available for trans-
port (the potential transport rate). At grid cells where the seawall con-
straint is violated, the shoreline position and the transport rate are
adjusted. These quantities in neighboring cells are also adjusted, as
necessary, to preserve sand volume and the direction of transport. The
calculation procedure is complex, and the reader is referred to Hanson and
Kraus (1986b) for full details. Flanking of the seawall is not possible since

it would lead to a double-valued shoreline position at the same grid cell.
Beach Fill

189. Beach fill is a traditional and increasingly popular method of
shore protection and flood control, and nourished beaches also have value for
recreational, commercial, and environmental purposes. Fill is commonly placed
together with the building of coastal structures such as groin fields and
detached breakwaters. GENESIS is capable of representing the behavior of

fills under the following assumptions:

a. The fill has the same median grain size as the native sand.

b. The profile of the fill represented in the model has the
equilibrium shape corresponding to its grain size.

c. The berm height of the nourished beach is the same as the

natural beach.

These assumptions are necessary since the transport parameters, shape of the
equilibrium beach profile, and berm height are considered constant for the
entire beach being simulated.

190. Although beach fills are constructed with a certain cross-
sectional area, after a certain time period, typically on the order of a few
weeks to months, the fill will be redistributed by wave action to arrive at
the equilibrium shape of the beach. As a shoreline response model, GENESIS
interprets any added width of beach as conforming to the equilibrium shape.
For implementation of fill in GENESIS, the modeler must compute the total
added distance Y,3g that the shoreline will be advanced. This distance is
known since the total volume of the fill equals the product of the depth of
closure plus berm height, alongshore length of the fill, and Y,g, . The
modeler must estimate if it is appropriate to remove a percentage of the total
fill volume that may be lost in fines. Such material is believed to be
carried offshore and out of the littoral system. GENESIS places the amount of
Yadq on the beach in equal increments Ay of shoreline advance along the
specified length of the project per time step over the user-specified con-
struction period of the fill. The amount Ay is added whether the waves are
calm or active.

191. The input change in shoreline position can also be negative,
resulting in shoreline recession instead of advance. This option is useful
for describing sand mining. In this case, the shoreline cannot recede

landward of a seawall.

Longshore Transport Rate: Practical Considerations

192. The empirical formula used to calculate the longshore sand trans-
port rate in GENESIS is given by Equation 2. The transport rate is obtained
as a function of the waves and shoreline/contour orientation at each time step
and at each grid point, except at pinned-beach boundaries. In this section
three important considerations are discussed which involve quantities composed
of transport rates as calculated from Equation 2. The topics usually
encountered in practical applications are:

a. Multiple transport rates as produced by multiple wave sources.

Derived transport rates (net and gross transport rates).

c. Effective threshold for longshore sand transport (calm and
near-calm wave events).

The first two items are treated within GENESIS in combination with appropriate
input file preparation, and the third item is treated in wave data file

preparation prior to running GENESIS.

Multiple transport rates
193. Waves arriving at the shore are typically produced by several

independent generating sources. Long-period swell waves were probably
generated from distant storms, whereas the shorter period "chop" or sea waves
were produced by local winds. Indeed, the WIS hindcast provides information
for both sea waves and swell. The modeler may have to deal with even more
than two wave sources. For example, for the southern coast of California,
three independent wave sources coexist during parts of the year: Northern
Hemisphere swell, local sea waves, and the Southern Hemisphere swell which
arises from storms as far away as the Antarctic Ocean. The Southern Hemi-
sphere swell occurs mainly in the interval from May through October and, in
some years, may be the dominant transporting wave component along the coast of
the southern California Bight.

194. The situation of multiple wave sources is handled through the
assumption that each wave source gives rise to an independent longshore sand
transport rate. GENESIS then calculates a total longshore sand transport rate
at each grid point i by linear superposition. Let Qim be the transport
rate at grid point i produced by source m _, of which there are M _ wave

sources. The total transport rate at i is

M
Qi a ) a (36)
m=1

GENESIS uses this quantity to calculate shoreline change.

195. As discussed in the next chapter, the interface of GENESIS
requires specification of the number of wave sources (called "NWAVES"
instead of M as above). The file holding wave data must similarly reflect

this number by containing wave data in sequence for the M_ sources at each

time step. On the basis of this information, GENESIS calculates Q, at each
time step, automatically accounting for the placement of beach fills, skipping
over wave data for calm events, and performing other "book-keeping" tasks that
depend on the time step in combination with the number of wave sources. Each

wave source increases computation time of the modeling system.

Derived transport rates

196. In shoreline change modeling, it is convenient to analyze long-
shore sand transport rates and shoreline change from the perspective of an
observer standing on the beach looking toward the water. Two directions of
transport can then be defined (SPM 1984, Chapter 4) as left moving, denoted by
the subscripts ft , and right moving, denoted by the subscripts rt . The
corresponding rates Qp, and Q,, do not have a sign associated with them,
i.e., they are intrinsically positive; information on transport direction or
sign is contained in the subscripts. Use of these two rates is convenient for
two reasons: first, the terminology is independent of the orientation of the
coast and, therefore, provides uniformity and ready understanding independent
of the coast; second, the awkwardness of dealing with the sign is eliminated.
Two other very useful rates entering in engineering applications can be
defined in terms of these basic quantities, the gross transport rate and the
net transport rate.

197. The gross transport rate Q, is defined as the sum of the trans-
port to the right and to the left past a point (for example, grid cell i) on

the shoreline in a given time period.

Q, = Qt + Qe (37)

A navigation channel at a harbor or inlet and a catch basin adjacent to a
jetty will trap sand arriving from either the left or the right. This
quantity is estimated by computing the gross transport rate.

198. The net transport rate Q, is the difference between the right-
and left-moving transport past a point on the shoreline in a given time

period. It is defined as

Qn = Qe = Qee (38)

The net rate is a vector sum of transport rates and is the quantity needed to
determine whether a section of coast will erode or accrete. The rates Q
used by GENESIS to compute shoreline change through differences in transport

rates alongshore are net rates.

Effective threshold for transport

199. Inspection of Equation 2 for the longshore sand transport rate
shows that the first and dominant term has a dependence on breaking wave

height and direction as
Oeve(H,)>/4esin265. (39)

since the wave group speed at breaking is C,, » (H,)1/2. Consider two break-
ing waves, one with height of 1 m and the other of 0.1 m, which have the same
angle at breaking. By Equation 39, the 1-m wave will have a transport rate
300 times greater than the 0.1-m high wave. For the same wave period and
deepwater direction, a higher deepwater wave will break at a larger angle,
also increasing the disparity in magnitudes of transport rates associated with
high/low waves and large/small deepwater wave angles.

200. A coast open to the ocean will experience a range of wave condi-
tions from completely calm to stormy. Because of the great amplification of
the longshore transport rate through the wave height and, to a lesser extent,
wave angle, it is reasonable to apply a cutoff or threshold to eliminate from
the times series wave conditions that have negligible transport rates and are
not significant factors contributing to shoreline change.

201. Empirical evidence for an effective threshold of longshore sand
transport was found by Kraus and Dean (1987), later revised by Kraus,
Gingerich, and Rosati (1988), based on sand trap measurements in the field for —
a sand of nominal grain diameter of 0.2 mm. Komar (1988) made a comprehensive
study on the physical controls on the longshore sediment transport rate and
concluded there is no empirical evidence that the rate depends on the grain
size for typical beach sands. This result implies that the criterion found by
Kraus, Gingerich, and Rosati should apply to any sandy coast. Kraus, Hanson,
and Larson (1988) developed a method for applying this threshold to eliminate

in an objective manner wave events that would produce negligible longshore

transport. In specific examples using hindcast and measured wave data, they
showed that in a certain case for the Atlantic coast of the United States as
much as 86 percent of the waves could be considered as effectively calm,
eliminating the necessity for performing the shoreline change calculation at
the particular time step in which they appear in the time series.

202. The procedure is applied by scanning the wave time series and
propagating waves to breaking by assuming plane and parallel bottom contours.
A modified time series of deepwater wave conditions is then developed in which
waves not satisfying the threshold criterion described below are made to
indicate a calm condition, accomplished by either setting the value of the
wave height to zero or the wave period to -999. In reading such a value,
GENESIS will move to the next wave condition if there are multiple waves per
time step or to the next time step, not executing the transport rate calcul-
ation and, possibly, not performing the shoreline change calculation if there
are no effective waves in the given time step.

203. The cutoff for effective longshore sand transport is given as
H,X,V = 3.9 (m?/sec) (40)

where

X, = width of the surf zone (distance between shoreline and breaker
line)

V = mean speed of the longshore current
For the purpose here, using X, ~ D,/tanf8 and Equation 14 (H, = yD,), the
width of the surf zone can be expressed as X, = H,/(ytanf). For V , Komar
and Inman (1970) empirically found that V = 1.35(H,/2) (yg/H,)1/2sin26,. for
the situation of the longshore current generated by obliquely incident waves.
Substitution of these expressions for X, and V into Equation 40 gives a
formula that can be used with a simple wave transformation program to test for

noneffective longshore transport conditions:

2 2G29) yalctang

H,°/4sin20x.
135 gil2

(41)

If the value of the left side of Equation 41 is less than or equal to the
threshold value on the right, then that wave condition in the deepwater time
series can be designated as calm. The GENESIS Workbook provides a program for
prescanning time series wave data for satisfaction of the threshold longshore
transport criterion. Note that Equation 41 is valid for metric units. If
American customary units are used, the empirical value of 3.9 m?/sec should be
changed to 138 ft?/sec. These values are expected to be revised as more field

data become available.

PART VI: STRUCTURE OF GENESIS

204. This chapter describes the general structure and operation of the
user interface of GENESIS and the preparations that must be made prior to
running the modeling system. Discussion is focused on the input and output
files comprising the interface. This and the succeeding two chapters provide
practical information needed to run GENESIS.

205. The predictive reliability of GENESIS depends on the quality of
the input data. A major portion of the shoreline change simulation effort
involves gathering, cleaning, interpreting, formatting, and entering data into
input files. The various types of data used by GENESIS are discussed in
Part V. Ina scoping application, data preparation and model setup typically
take 1 to 2 months, depending on the scale of the project; the time for model

preparation and setup for design studies is typically 2 to 6 months.

Preparation to Run GENESIS

Coordinate system and grid
206. As discussed in Part V, a coordinate system and grid are laid out

on a nautical chart or aerial photographs covering the region of the project,
and measured shoreline positions, locations and configurations of structures
and beach fills, and other topographic and geometric information are expressed
in the coordinate system as a function of grid cell number alongshore and
distance offshore. Alongshore location is specified by grid cell number
rather than distance in order to allow the precise control of positioning.

The grid is discretized alongshore (along the x-axis), whereas shoreline
positions and other quantities specified along the y-axis are continuous.
Length units can be selected as either meters or feet, and all input and
output will use those units.

207. A schematic example of the coordinate system and a grid is shown
in Figure 19. The vertical scale is exaggerated since the longshore extent
covered is typically thousands of meters or feet, whereas shoreline change is
typically tens or hundreds of the corresponding units. In shoreline applica-

tions, such figures are drawn with the observer positioned on land and the

boundaries to the left and right, as described in Part V. Notation used in

this figure is also described in Part V.

GATED OR PINNED—BEACH

waa BOUNDARY AT CELL WALL 1

GROIN,
BREAKWATER TIP,
OR END OF SEAWALL
AT CELL WALL i

a GATED OR PINNED—BEACH
z BOUNDARY AT CELL WALL N+1
re SHORELINE

(eo)

CELL NO

DISTANCE ALONGSHORE/GRID CELL NUMBER

Figure 19. Example of a coordinate system and grid used by GENESIS

208. A right-hand coordinate system is drawn with the x-axis (baseline)
parallel to the trend of the shoreline and the y-axis perpendicular to it and
pointing offshore. It is convenient to place the baseline landward of coastal
structures and any expected or historical position of the shoreline so as to
deal with only positive-valued shoreline positions, although this need not be
the case. The shoreline grid along the x-axis consists of N cells defined
by N+l cell walls. Boundary conditions must be specified at cell walls 1
and N+l . Internally in GENESIS, longshore sand transport rates, positions
of structures, and boundary conditions are located at cell walls, and shore-
line positions are located in the middle of cells. Cell wall 1 is placed at

the location where the left boundary condition is implemented, and the grid

cell spacing should be determined such that major shoreline features are
resolved. Distances are read on the grid with cell wall 1 as the origin;
that is, the y-axis intersects the x-axis at grid wall 1 , not at "zero."

209. GENESIS Version 2 uses a uniform alongshore grid, and the spacing
between all shoreline positions is Ax . Positions on the grid defining the
ends of structures, of which terminal groins or jetties are a typical case,
are located at a distance Ax/2 from adjacent shoreline position cells, since
sediment transport rates are calculated at grid cell walls. In the example of
Figure 19, a tip of a detached breakwater (groin, seawall) is assigned to
position i ; GENESIS will place the tip of the structure at cell wall i and
not at shoreline position i , which is in the middle of the cell. As another
example, the jetty located on the left boundary of the grid is a distance
Ax/2 to the left of shoreline position coordinate y, ; the shoreline starts
at the location of y, , not at the jetty. Concerning beach fills, since a
fill moves the position of the shoreline, the grid locations of the two
lateral ends of a fill are at shoreline positions, not cell walls.

210. All historic shoreline position data must be translated to the
coordinate system and placed on the grid. Structures are usually assigned the
cell number at which they would naturally reside, but the modeler is free to
use judgment. For example, if an already short detached breakwater would be
further shortened by following standard procedure in placing it on the grid
(due to roundoff to the nearest cell position), one tip could be "moved" to
the next cell to increase the effective length of the structure.

211. %It is also possible to simulate shoreline change along a subsec-
tion of the grid, in which case consideration must be given to boundary condi-
tions at the two ends of the subsection. It is recommended to check the
results of preliminary model runs for longshore and offshore locations of

topographic information to confirm that it was entered correctly on the grid.

Lateral boundary conditions
212. As described in Part V, GENESIS allows two types of lateral

boundary conditions to be implemented, a "gated" boundary and a "pinned-beach"
boundary. The default condition is the pinned beach; if a groin is not placed
on cell wall 1 or N+1 _, the boundary will be treated as a pinned beach,

allowing sand to freely cross it from both sides.

ZU Ye

Gated boundary. A gated boundary condition (Figure 20) is

implemented at a terminal grid cell (grid cell walls 1 and N+l1) if the

modeler specifies a groin (or jetty or shore-connected breakwater) in the

respective cell. The amount of sand entering or leaving the grid at a gated

boundary is determined by the distances from the shorelines on either side of

the groin to the seaward end of the groin, the beach slope at the groin, and

the permeability of the groin. In Figure 20, the distance from the shoreline

to the end of jetty outside the grid on the right boundary y gy was made very

long (as specified in the model input) and the permeability set to 0. (Such

a condition might occur if an inlet is located to the right of the grid.) The

jetty therefore appears infinitely long and high from outside the grid on the

right, and no sand will be transported onto the grid. However, transport off

the grid at the right boundary may occur and will depend on the distance from

the shoreline to the end of the jetty inside the grid and the wave conditions

(which determine the depth and location of the longshore sand transport).

SHORT EFFECTIVE JETTY LENGTH; LONG EFFECTIVE JETTY LENGTH
SAND CAN PASS FROM EITHER SIDE ON OUTSIDE; SAND CAN LEAVE
GRID BUT NOT ENTER

iy)

N
N
N
N
NE Yon
N>
N
NY

ASSUMED N

SHORELINE N

POSITION N
N
N
N
N
N
N
N
RN == —

DISTANCE ALONGSHORE \

N
N ASSUMED
N SHORELINE
N POSITION

Figure 20. Gated boundary condition

100

214. On the left boundary of the grid in Figure 20, the jetty of the
same length as that on the right boundary may allow sand to enter as well as
leave the grid since its effective length on the outside yg, was made
comparatively short. The gated boundary condition thus allows considerable
flexibility to control the rate of sand transport across the boundaries.

215. Pinned-beach boundary. The pinned-beach boundary condition repre-
sents a beach that has exhibited a long-term trend of stability. This
condition is implemented as a default boundary condition. A pinned-beach
boundary can be used in situations where a long sandy beach is located far
from the project and has not or is not expected to change greatly in position.

216. The four possible combinations of the lateral boundary conditions
are illustrated in Figure 21. The boundary conditions are independent and
represent the modeler’s interpretation of the physical situation. For small
projects, pinned-beach boundaries are sometimes used and placed far from the
project (for example, five project lengths to each side). The independence of
the result on this distance should be checked by varying the distance. Care

must be taken if the simulation interval is long or the transport intense.

GROIN AT
i=! GROIN AT

1 N+1 1 N+1

y
GROINS AT
1=1, I=N+1
Z2ZZZA

y
as
4
+

1 N+1

Figure 21. Combinations of lateral boundary conditions

101

Input Files

217. GENESIS is operated through use of six input data files, as
illustrated in Figure 22. Input and output file names consist of five letters
with the three-letter extension ".DAT." Input files contain the modeler’s
conceptualization of the project site, the factors that influence shoreline
change from the perspective of shoreline change modeling, and data and
technical information to run the simulation. GENESIS reads the input files
and performs the shoreline change simulation according to the instructions and
data contained in them. The present chapter deals in great part with the
content and preparation of the input files.

218. Appendix B contains blank copies of input files that may be
photocopied for use in projects or in working through the case study presented
in Part VIII. Segments of START files, the main interface file for running

GENESIS, are given in Part VII in discussion of examples.

START

SHORL SEIU
SEAWL
OUTPT
DEPTH

WAVES SHORC .

SHORM

Figure 22. Schematic of input and output file structure of GENESIS

102

219. All input files begin with four header lines, and GENESIS skips
over these when the files are read. The header lines are available to the
user for documentation purposes, for example, to give the name of the file and
title of the run, describe the format of the data contained in the file, and
note any special conditions associated with the data or run. Whether or not
these lines are used, exactly four "dummy" lines must appear in the header of
every input file. If the four header lines are not present, GENESIS will
either begin reading data at an incorrect position with a possible undetected
computation error or give a runtime error that will be very difficult to
trace, since the false data may cause a program crash at an arbitrary line of
code.

220. The six input files which GENESIS will look for when it is
executed are named START.DAT, SHORL.DAT, SEAWL.DAT, DEPTH.DAT, WAVES.DAT, and
SHORM.DAT. Of these files, START, SHORL, WAVES, and SHORM are always re-
quired, whereas SEAWL and DEPTH may or may not be called by GENESIS, depending
on instructions entered by the user in the START file. These files are
discussed below, and examples of file preparation are given in Parts VII and
VIII.

221. The aforementioned names are exactly those used by GENESIS. A
project, however, may require many versions of the input files, particularly
START files, since these files contain most of the information specifying
project alternatives. As an example of a very simple situation involving
multiple START files, if only two alternatives are considered in a project,
detached breakwaters as one alternative and groins as the other, the modeler
would probably construct two START files, possibly named START _BW and
START_GR. When he or she is ready to run GENESIS for the detached breakwater
alternative, the file START_BW would be copied into START.DAT. Later, when
the groin alternative is to be run, START_GR would be copied into START.DAT.
The various start files employed can be saved under their original names
together with the output to document the process of evaluating the alterna-
tives and results. Different START files are also needed in the calibration

and verification procedure.

103

222. The input file START.DAT contains the instructions that control
the shoreline change simulation and is the principal interface between the
modeler and GENESIS. Once a generic START file for a project is prepared,
typically only a few quantities in it will need to be changed during the
course of verification, sensitivity testing, design optimization, etc.

223. Figure 23 shows an example of a START file. The START file
contains requests for information in a series of lines arranged in sections
according to general subject. Lines of text (the request portion) should be
neither added nor deleted from the START file, as GENESIS will skip over these
request lines to read the input values. Also, the line request identifier
letter (A.1, B.1, C.1,...) should not be moved from column 1, as GENESIS looks
for it there. However, the number of lines holding values in response to a
specific request is arbitrary. Unless instructed otherwise, a response (an
alphanumeric character) must be given to a request. If several values are
required, they may be separated by a space or by a comma, or both.

224. Names of internal variables, particularly values that will be used
to dimension arrays, are given in parentheses in the requests. To aid asa
reference in using this manual, the key variable associated with the request
is given at the start of each paragraph below. These names also appear in
error messages and are needed when discussing START file configurations with

others.

A. Model setup
225. Line A.1: TITLE. The first line of the START file requests a

project title, which may be up to 70 characters long. The title line normally
contains descriptive information about the particular run, for example,
"ILLUSTRATIVE EXAMPLE FOR MANUAL" or "LAKEVIEW PARK: CALIBRATION RUN."

226. Line A.2: ICONV_. The variable ICONV is a flag telling
GENESIS the length units of the calculation. Calculations are performed by
using either meters or feet, as selected at Line A.2. All length, height, and
depth inputs, including wave height, water depths, seawall positions, etc.,

must be given in the specified units, and output will similarly be expressed

104

in these units. (The only exception is median grain size diameter on Line
C.1, which must be given in millimeters. )

22s (eine JAC3 = NN DX __. The total number of calculation cells NN

(called "N" in the text of this report) and the cell length DX (called
"Ax") are entered here. The product NN*DX gives the total length of the
modeled reach.

228. Line A.4: ISSTART , N_. This request allows the user to perform

simulations over a portion of the grid through specification of starting and
ending grid cells (boundaries) other than 1 and N+l , respectively. This
option is useful if a long grid has originally been prepared but, ina
particular application, details of shoreline change along a subsection are to
be studied. It is cautioned that the numbers of the starting cell ISSTART
and ending cell N of the subsection grid must be located in physically
reasonable areas for meaningful results to be obtained. In almost all circum-
stances, lateral boundaries should be placed either at a long groin or jetty
or at a historically stable section of coast. It is recommended that this
option not be exercised until experience is gained running GENESIS. If
simulation of shoreline change in a subsection is not performed, the values of
ISSTART and N_ should be 1 and NN (as specified on Line A.3), respec-
tively. By setting N equal to -1 , GENESIS will set N equal to NN , and
the value of N does not have to be changed for each new application.

229. Line A.5: DT. For a specific simulation interval, smaller
values of the duration of the time step DT (called "At" in the main text
of this report) increase the computational run time, whereas larger values of
DT result in a less accurately predicted shoreline position. A time step of
6 hr is recommended for design, but longer time steps may be used, for
example, 24 hr, depending on the variability of the input waves. Scoping
applications will typically use a long time step (on the order of 24 hr). The
wave data input file (WAVES) must be designed to provide wave data at the
specified time step. To satisfy this requirement, DT must be a proper
fraction (e.g., 1/2, 1/4) of the time step DTW defining entries in the wave
file (Line B.6).

230. Line A.6: SIMDATS . The date when the calculation starts

SIMDATS is needed to key GENESIS for selecting the correct season of waves,

105

coordinating beach fills, and entering changes in structure configurations.
The input format is defined as a six-digit number, with two digits each repre-
senting the year (YY), month (MM), and day (DD) in that order, i.e., YYMMDD.

A full six-digit number must be specified for proper starting of the WAVES
file.

231. Line A.7: SIMDATE . The simulation interval can be specified in
terms of either the number of time steps or the date SIMDATE in simulation
time. During testing and scoping, for which the model is run for only a few
time steps, it is convenient to use the number of time steps. In design mode
the dates of measured shorelines are known, and it is convenient to work in
simulation time. GENESIS distinguishes time step and date input through the
magnitude of the value of SIMDATE ; if SIMDATE is greater than or equal to
180,000, GENESIS will interpret it as a date, whereas if the value is smaller
than 180,000, GENESIS will interpret it as the number of time steps.

232. Line A.8: NOUT . In many situations it is very informative to
study the time evolution of the calculated shoreline change. For example, in
design mode, for which simulations are made over several years, the shoreline
location at the end of each month or each year may be desired. The value
entered here NOUT specifies the total number of simulated times when output
should be written to file (OUTPT.DAT, discussed below). The output of data at
the final time step does not have to be included, since it is a default
output.

233)) 0) Line rA.9 ss TOULRGCE . Output may be specified by either the
number of time steps or the corresponding dates in simulation time. The
number of outputs TOUT(I) (time steps or dates) specified must match the
number entered on Line A.8.

234. Line A.10: ISMOOTH . The representative contour used in the
internal wave calculation is calculated through an alternating direction
moving average algorithm. The variable ISMOOTH specifies the size of the
moving window over which the average is calculated. If ISMOOTH is set equal
to 0 , no smoothing is performed, and the representative contour will follow
the shoreline. If ISMOOTH is set to N , the representative contour will be
a straight line parallel to one drawn between the two end points of the

shoreline.

106

235. Line A.11: IRWM_. The variable IRWM allows the user to
suppress printout of repeated warning messages (see the section "Error and
Warning Messages"). For example, if a preliminary or scoping analysis is
being performed with a long time step, the value of the stability parameter
STAB (called Rg, in the main text) is likely to exceed 5.0, and a warning
message will be issued at every time step. If IRWM is set equal to zero,
only one warning message will be given, and the screen and output file SETUP
will not be cluttered with warning messages. In planning and design applica-
tions, the modeler will want to be aware of potentially undesirable conditions
and should set IRWM = 1

236. Line A.12: Kl, K2__. Values of the longshore sand transport

calibration coefficients Kl and K2 (called "K," and "K," in the main
text) require adjustment in the process of model calibration. For sandy
beaches experience has shown that values are typically in the ranges of
ORK <0 and OL] 5KI << K2-< 15K. initial! trial’ runs! might use
Kl = 0.5 and K2 = 0.25 . The transport parameter Kl controls the time
scale of the calculation and is the principal calibration coefficient in
GENESIS. Further discussion is given in Part V. (Note: the above-mentioned
values of Kl and K2 correspond to rms wave height. Significant wave
height should be entered in the WAVES file, however, as GENESIS automatically
converts heights in the wave file from significant to rms.)

237. Line A.13: IPRINT . A computer program, in this case GENESIS,
can be executed in two ways on most mainframe computers, by interactive mode

(sometimes called demand mode) and by batch mode. In interactive mode,

instructions are entered from the keyboard and reproduced on the monitor or
printer; in this mode the terminal launching the job is devoted fully to
execution of the program. In batch mode, the job is launched through a batch
file devised by the user. The batch file contains commands and other data
required to run the program and acts as a substitute for entries made at the
keyboard. A job launched in batch mode will execute in the background and
free the user’s terminal for other applications. If GENESIS is executed in
interactive mode, through IPRINT a counter can be requested to appear on the
screen to show the time step presently being executed. The counter will be

updated without causing the screen to scroll. If the counter is activated in

107

batch mode, one line will be printed in the default "log" file at each time
step. The time step counter is activated by setting IPRINT = 1 and sup-
pressed by setting IPRINT = 0

B. Waves

238. Line B.1: HCNGF , ZCNGF , ZCNGA_. The wave height change
factor HCNGF multiplies the wave height along the reference line (or
multiplies the deepwater wave height if the internal wave model in GENESIS is
used; see Line B.3). The wave angle change factor ZCNGF performs a similar
operation on the wave angle. The wave angle amount ZCNGA is added to (or
subtracted from, if negative) wave angles along the nearshore reference line
(or from the deepwater wave angle if a nearshore reference line is not used).
The change parameters allow quick answers to be obtained to scoping questions
such as "What if the waves are 20 percent higher" or "What if the waves arrive
from 5 deg farther out of the east than the hindcast indicates?" In order to
run with the original, unchanged wave input (the normal situation), the value
of the wave height change factor is 1.0, the wave angle change factor is 1.0,
and the wave angle change amount is 0.0.

239. Line B.2: DZ. The depth of the offshore wave input DZ is
required in order to refract waves to breaking. This depth corresponds to the
depth at which waves originated if a refraction model was used to bring waves
to a nearshore reference line or the depth of the input time wave record if a
refraction model was not used, as specified on Line B.3.

240. Line B.3: NWD. The value specified for the flag NWD deter-
mines whether the waves will be refracted internally by GENESIS from the wave
data contained in the input file WAVES.DAT (in which case NWD = 0 and the
input wave data correspond to an offshore location) or if the file WAVES
already holds wave information along the nearshore reference depth line (NWD
= 1), in which case a refraction routine (for example, RCPWAVE) has already
been used to bring waves to relatively shallow water.

241. Line B.5: ISPW . For simulations covering large spatial extent,
it may not be computationally feasible to run the wave refraction model using
the same (relatively fine) spatial alongshore resolution as that specified in

GENESIS. By setting ISPW to an integer greater than unity, the size of the

108

wave calculation cells alongshore will be a multiple of the cell length used
by GENESIS.

242. Line B.6: DTW. In situations where the temporal resolution of
the available wave data is not as great as the time step DT to be used in
the simulation, it is possible to run GENESIS with repeated wave conditions at
each time step, as specified by the variable DTW . As an example, suppose
wave data are only available at 24-hr intervals, but the model is to be run at
the standard 6-hr time step to maintain numerical accuracy and/or stability;
then by specifying DTW = 24 on line B.6 (and DT = 6 on line A.5), each set
of wave conditions in the WAVES file will be run four times. Repetition of
wave data is also used in the modeling of simple hypothetical cases in which
constant wave conditions may be acceptable throughout the entire simulation;
DTW can be set to be equal to or greater than the total simulation time in
hours determined by the values specified at Lines A.5 through A.7. Then the
first wave condition in the WAVES file will be run at every step.

243. Line B.7: NWAVES . The variable NWAVES. provides the number of
independent wave sources per step. Wave measurements often show two or more
spectral peaks, indicating the presence of distinct wave trains. For example,
swell may arrive from a distant storm, whereas sea waves are generated by
local winds. These two types of waves are independent and will have different
heights, periods, and directions. Also, WIS provides sea and swell components
separately. GENESIS allows input of an arbitrary number of wave components.
These are treated independently, with each component generating a longshore
sand transport rate. The transport rates from each wave component at a given
time step are added linearly, including sign, to give the net transport rate
at that time step.

244. As another situation in which an extra wave component might enter
a simulation, a long jetty may reflect a significant portion of the incident
wave energy. If reflected waves are believed to appear in the breaking wave
climate and influence shoreline evolution in the area, a time series of these
waves may be included as a component in the WAVES file.

245. Line B.8: WDATS . The starting date of the shoreline change
simulation was given at Line A.6. From the date of the start of the wave file

WDATS entered at the present line, GENESIS determines the location in the

109

WAVES file corresponding to the start of the simulation. In most verifi-
cations and in all predictions, contemporaneous measured wave data do not
exist for the simulation interval, and the input file WAVES is viewed as
holding representative wave data for a number of typical years. Therefore, it
is the number of years, starting from a particular month and day (season) that
is usually important, not the actual date of the year. Simulation results for
a beach fill placed in late spring or early summer will probably be much
different than if the fill were placed under stormy winter waves. By begin-
ning the simulation at the appropriate month and day, the phase of seasonality
is preserved. It is a happy day in a modeler’s life if gage or hindcast wave
data are available over the full calibration or verification interval. If so,
these data should be used.

246. The modeler will normally specify the date of the start of the
WAVES file (i.e., WDATS) such that the simulation will begin at the first
month and day occurring in that file. If it is desired to start the simula-
tion in a year other than the first year appearing in the WAVES file, then the
starting date of the WAVES file should be changed to move the starting pointer
to the required year, month, and day. As a specific example, if the modeler
wants to start the simulation in the second year of the wave data set rather
than the first year, the starting date of the WAVES file should be set to one
year later. The effect of seasonality in the wave data on shoreline response

can be investigated by starting the WAVES file in different months.

C. Beach

247. Line C.1: D50 _. GENESIS uses the median diameter of the sand
D50 (called "d.." in the main text) to compute an equilibrium profile shape.
The profile shape determines the distance from the shoreline to the point of
wave breaking at each grid cell and hence the effective zone of longshore sand
transport. The location of breaking also determines whether diffraction will
take place, as sources of diffraction must lie seaward of the breaker zone.
Figure 7 can be consulted for selecting an appropriate value of dg,

248. Line C.2: ABH. The average berm height ABH (called "D," in
the main text) above the mean water level or the datum used in the modeling

is entered here.

110

249. Line C.3: DCLOS_. The closure depth DCLOS (called "D," in
the main text) defines the seaward limiting depth of profile movement. It is

entered here, referenced to the same datum as the average berm height.

D. Nondiffracting groins
250. The lengths of groins and short jetties are normally on the order

of the average width of the surf zone; wave diffraction produced by such

structures can be considered to be negligible, since in shallow water the
waves will arrive almost normal to the tip of the structure or will have

already broken. Thus, typical groins used for shore protection and short
jetties should be treated as nondiffracting structures.

251. GENESIS distinguishes between groins (and jetties) that produce or
do not produce wave diffraction. Model computation time associated with a
diffracting structure is much greater than for a nondiffracting structure;
therefore, the number of diffracting groins should be minimized. The diffrac-
tion option, starting at Line E.1, is mainly used to describe long jetties
(jetties with lengths on the order of several surf zone widths) and harbor
breakwaters that act as a long jetty by almost completely blocking longshore
sand transport; these types of structures extend well beyond the surf zone
where waves may arrive at a large oblique angle, resulting in a wide diffrac-
tion zone. They also block sand transport alongshore and, therefore, are
functionally equivalent to groins with regard to shoreline change.

252. GENESIS can accommodate a large number of simple groins and more
complex structural configurations composed in part of simple groins. Part VII
gives examples of START file instructions for complex configurations of
structures including groins.

253. Line D.1: INDG. Line D.1 asks if there are groins and short
jetties on the calculation grid used in the particular simulation, setting the
flag INDG . The great majority of groins as well as jetties at small
channels do not extend beyond the average width of the surf zone; therefore,
they should be treated as nondiffracting structures that interrupt the
movement of sand alongshore. Bypassing of sand seaward around such structures
is automatically calculated by GENESIS. If the value 1 ("yes") is placed at
Line D.1, then responses are required at Lines D.3-D.5. If there are no short

(nondiffracting) groins or jetties on the grid, a value of O ("no") should

aie:

be placed at Line D.1, and no other questions beginning with the letter D need
to be answered. (If O is placed at Line D.1, Lines D.3-D.5 will not be read
by GENESIS, and values remaining there may be arbitrary. )

254. Line D.3: NNDG. Enter the number of nondiffracting groins and
jetties NNDG located on the grid. This number also includes structures that
may serve as a groin boundary condition on one or both lateral ends of the
grid.

255. Line DEG: PXNDGCGL . Enter the grid cell numbers of nondif-
fracting groins and jetties IXNDG(I) in order of increasing cell number.

The number of grid cell locations given here should equal the number of
nondiffracting groins specified at Line D.3 (NNDG values).

2504) inesDione a YNDGCR . Enter the lengths of the nondiffracting
groins and jetties YNDG(I) (as measured from the x-axis to the seaward tip
of the structure) in the order of cell number in which they occur (NNDG
values in increasing order of cell numbers corresponding to the locations
given at Line D.4).

E. Diffracting
groins and jetties

257. Line E.1: IDG. If there are long jetties and long groins on
the grid (i.e., structures that extend past the breaking wave zone and into
relatively deep water for almost all wave conditions), they should be treated
as diffracting structures and the value 1 ("yes") placed here in the flag
IDG . If there are no such structures on the grid, including the boundaries,
then respond with the value 0O ("no"), and skip questions E.3-E.6. (If 0
is placed at Line E.1, Lines E.3-E.6 will not be read by GENESIS, and values
remaining there may be arbitrary.)

258. Line E.3: NDG. Enter the number of diffracting groins and
jetties NDG that are on the grid. This number includes structures that may
serve as boundary conditions (at grid points 1 and N+l).

259.) einew hae EXD GOL . Enter the grid cell numbers of diffracting
groins and jetties IXDG(I) in order of increasing cell number. There should
be the same number of grid cell locations as the number of diffracting groins
and jetties specified at Line E.3 (NDG values from small to large cell

numbers).

112

260. Line E.5: YDG(I) . Enter the lengths of the diffracting groins
and jetties YDG(I) as measured from the x-axis in the order of cell number
in which they occur (NDG values from small to large cell numbers correspond-
ing to the locations given at Line E.4).

261. Line E.6: DDG(I) . Enter the depths at the tips of the dif-
fracting groins and jetties DDG(I) in the order of cell number in which they
occur (NDG values from small to large cell numbers corresponding to the

locations given at Line E.4).

F. Groins/jetties

262. Line F.1. This section requests general information pertaining to
both nondiffracting and diffracting groins and jetties (and shore-connected
breakwaters). If there are no groins or jetties on the grid (values of 0
entered at both Lines D.1 and E.1), then Lines F.2-F.5 may be skipped. If
there are groins of any type, responses to Lines F.2-F.5 must be given. (If
there are no groins or jetties on the grid, Lines F.2-F.5 will not be read by
GENESIS, and values remaining there may be arbitrary.)

263. Line F.2: SLOPE2 . Groins impound sand on the side of pre-
dominant direction of drift, implying that the beach slope near a groin is
milder than the equilibrium slope. An estimate of this slope SLOPE2 should
be made by reference to measurements at the site or to other data. GENESIS
uses this value in calculation of sand bypassing around the seaward tips of
groins and jetties.

264. Line F.3: PERM(I . Permeabilities PERM(I) (called "P" in
the main text) of the groins and jetties must be assigned. Permeabilities
should be given in order of increasing cell location of the structures as they
appear on the grid, irrespective of whether the structure is nondiffracting or
diffracting.

265. The permeability coefficient empirically accounts for transmission
of sand through and over a groin. (Bypassing of sand around the seaward end
of groins is automatically calculated by GENESIS.) A permeability value of
1.0 implies a completely transparent groin, whereas a value of 0.0 implies
a high, impermeable groin that does not allow sand to pass through or over it.
(Note: A completely transparent groin is not necessarily equivalent to a

natural beach (no groin): a representative beach slope (Line F.2) must be

ake}

specified for the beach in the vicinity of groins, and this slope will usually
be different (milder) than the equilibrium beach slope calculated with the
representative grain size.)

266. Since a methodology does not presently exist to allow GENESIS or
the modeler to calculate groin permeability by a standard or objective
procedure, this quantity is best determined as part of model calibration. If
a shoreline reach has numerous groins of various construction types and states
of functioning, it is recommended that estimates of relative permeability be
given initially and then refined in the course of the model calibration by
observing the trend of shoreline change near the groins. As a rule of thumb,
an apparently fully functioning groin with a crest above MSL for most tides is
assigned an initial permeability value in the range of 0.0 to 0.1, whereas a
groin that has gaps or is overtopped during parts of the tidal cycle may have
a permeability in the range of 0.1 to 0.5. An effective method of estimating
relative groin permeability is to compare the condition (number and width of
gaps, thickness and height of groin) of groins on aerial photographs of the
model reach.

267. Lines F.4.and_F.5: YGl_, YGN _. If a groin or jetty is llocaited
on a boundary (grid cell number 1 or N+1), the distance from the shoreline
outside the grid to the seaward end of the structure YGl and/or YGN must
be specified (called "yg," and "yg" in the main text). Since this loca-
tion is "off the grid," it must be given externally (by the modeler) and
cannot be calculated. This distance is used in the sand bypassing calculation

for the structure in situations where sand may be transported onto the grid.

G. Detached breakwaters

268. GENESIS treats a detached breakwater as a structure with two dif-
fracting ends. The tips of detached breakwaters can be placed at different
distances from the x-axis, and gap widths and breakwater lengths can also be
arbitrary if a line of segmented detached breakwaters is to be represented.
Generally speaking, detached breakwaters should be placed a distance offshore
that is at least as far as the location of the average wave breaker line, to
simulate the full diffracting effect of the detached breakwaters. If at any

time step the waves break seaward of a detached breakwater, the wave height at

114

the diffracting tip will be set equal to the depth-limited wave height deter-
mined by the relation H, = 7D, .

269. GENESIS Version 2.0 does not allow formation of a tombolo; i.e.,
the model will fail if the shoreline reaches or comes close to the breakwater.
It should also be noted that common diffraction theories, including the one
used in GENESIS, are technically invalid if the structure is very short (a
fraction of a wavelength) or for distances from the breakwater less than about
one wavelength. Placement of detached breakwaters should be made carefully in
light of these limitations.

270. A variety of configurations of detached breakwaters can be repre-
sented in GENESIS. Part VII gives examples of more intricate placements of
detached breakwaters and the associated instructions in the START file.

271. Line G.1: IDB. If there are detached breakwaters on the model
grid, the value 1 ("yes") of the flag IDB is entered here. If there are
no such structures on the grid, including the boundaries, answer with the
value O ("no"), and skip Lines G.3-G.9. (If the value O is placed at Line
G.1, Lines G.3-G.9 will not be read by GENESIS, and values remaining there may
be arbitrary. )

272. Line G.3: NDB. Enter the number of detached breakwaters NDB
that appear on the grid.

273. Lines G.4 and G.5: IDBl , IDBN.. The flags IDBl and IDBN

tell GENESIS if there are detached breakwaters crossing the boundaries

(no = 0; yes = 1). If a model boundary is placed across a detached break-
water, waves diffracted by the tip of the breakwater located outside the grid
will not be taken into account. Thus, such a structure will be regarded as
semi-infinite with only the tip of the breakwater lying within the grid to
produce diffraction.

274. The capability of placing detached breakwaters across grid boun-
daries should be used with caution. If a groin is not simultaneously located
on the boundary, GENESIS will apply the default pinned-beach boundary condi-
tion, which may not be appropriate in the shadow zone of the detached break-
water. The true meaning of the pinned-beach boundary condition is "the beach
does not want to move"; if the pinned-beach boundary condition is improperly

used, it may incorrectly mean "the beach is not allowed to move."

115

275). LinesGi622 2EXDB GH. . Enter the grid cell numbers of the tips of
detached breakwaters IXDB(I) in ascending order of cell number. There
should be two values for each detached breakwater located entirely within the
calculation grid and one value for each additional detached breakwater
extending across the calculation boundary.

2/6) PLineeGa/ ee YDBGE . Enter the distances from the tips of the
breakwaters to the x-axis YDB(I) in ascending order of cell number. There
should be the same number of values as specified at Line G.6.

277. Line G.8: DDB(T . Enter the depths DDB(I) at the tips of the
breakwaters in ascending order of cell number. There should be the same
number of values as specified at Line G.6.

278. Line G.9: TRANDB(I . Enter the value of the wave transmission
coefficient TRANDB(I) (called "K,;" in the main text) for the individual
breakwaters (NDB values) in ascending order as the structures appear on the
grid. This empirical coefficient accounts for wave transmission through a
breakwater and by overtopping, and it must be evaluated either externally or
as part of the calibration process, similar to the case of groin/jetty
impermeability. The value of the wave transmission coefficient varies between
0.0 and 1.0 , where the value 0.0 describes a high, impermeable breakwater
with no wave transmission through the structure by any means, and the value

1.0 describes a completely wave-transparent, ineffective structure.

H. Seawalls

279. A seawall constrains the allowable position of the shoreline
because the beach cannot erode landward of the wall. Formally, GENESIS can
describe only one seawall. However, noncontiguous sections of a seawall can
be represented by placing the number -9999 in the SEAWL input file along the
shore where seawalls are not present. Values of -9999 are assumed to place
the seawall at locations so far landward that the wall would never come into
play in the longshore transport and shoreline change calculations.

280. Line H.1: ISW_. If there is one or more seawall sections along
the modeled beach, the value 1 ("yes") is entered here for the flag ISW.
If there are no seawalls, the value O ("no") is entered and Line H.3 can be
skipped. (If the value O is entered at Line H.1, Line H.3 will not be read

by GENESIS, and values remaining at Line H.3 may be arbitrary.) If there are

116

no seawalls present, GENESIS will not read from the input file SEAWL and will
place the seawall at -9999 distance units as a default; values in the SEAWL
file may be arbitrary in this case since the file will not be read.

281. Line H.3: ISWBEG , ISWEND . As stated in the preceding two

paragraphs, if several seawall sections are present, they will be treated as a
single seawall but with the sections between them located far landward of the
shoreline. The grid cell numbers to be entered at this line correspond to the
beginning ISWBEG and ending ISWEND of the single, continuous seawall. The
two grid cell numbers are entered in ascending order. If ISWEND is set equal
to -1 at line H.3, internally GENESIS will set ISWEND = N_, which is a
convenient default if all applications or variations for a project have a

seawall running from ISWBEG to N .

I. Beach fills

282. If more than one beach fill occurs, information must be entered in
order of occurrence of the fills. Fills may overlap in time and location, but
information must be entered in the same order at each request. GENESIS treats
the fill as having the same grain size and same berm height as the original
beach.

283. GENESIS does not operate by direct use of fill volume but through
the total distance of shoreline advance after the fill and beach profile have
been molded to an equilibrium shape by wave action. (This distance must be
specified by the modeler at Line I.8.) GENESIS places the fill by advancing
the shoreline position in equal amounts at each time step between the starting
and ending dates of the operation and within the cells defining the fill, as
specified at the START file line numbers described in the following para-
graphs. The fill is placed even if wave conditions are not sufficient to move
sand alongshore and the shoreline change computation is not carried out (for
example, during calm wave conditions).

284. Because GENESIS places fill by advancing the shoreline in equal
daily amounts over the duration of the nourishment operation, a single fill
advances uniformly over its longshore extent. A nonuniform advance over a
given reach can be simulated by specifying several fills of different amounts

on different sections of a total reach but placed within the same period.

aaLY/

285. Line I.1: IBF. If one or more beach fills is placed during the
simulation period, a value of 1 ("yes") should be entered for the flag IBF
and responses given at Lines 1.3-1.8. If there are no beach fills, a value of
QO ("no") should be entered, and the remaining questions in this subsection
may be disregarded. (If O is placed at Line I.1, Lines I.3-1.8 will not be
read by GENESIS, and values remaining there may be arbitrary. )

286. Line 1.3: NBF_. The number of beach fills NBF that occurs
during the simulation period is entered here.

287. Lines 1.4 and 1.5: BFDATS(I BFDATE(1I . The dates or time
steps when placement of the fill(s) is begun BFDATS(1I) and ended BFDATE(1)
are respectively entered at these two lines, in chronological or increasing
order from the beginning dates or time steps of the fills (NBF values,
corresponding to line I.3). GENESIS keeps track of the date from the start of
the simulation (Line A.6), and, if the fills are specified in terms of dates,
GENESIS begins placing the fill on the beach at the date(s) specified.

288. Lines 1.6 and I.7: IBFS(I IBFE(I . The grid cell numbers of
the starting IBFS(1I) and ending IBFE(I) locations of the fills are entered
at Lines 1.6 and I.7, respectively, in the same order as entered at Lines 1.4
and 1.5 (NBF values). The cell number where a particular fill is started
must be smaller than the cell number where it is ended. The fill is placed in
all cells between and including the starting and ending cells.

289. Line 1.8: YADD(I) _. The amount of shoreline advance (advance of
the berm) YADD(I) that will be added to the existing shoreline by GENESIS
between the beginning and completion dates of the fill is given here. The
distances of shoreline advance should be entered in the same order as in
Lines 1I.4-I.7.

290. For a certain time period (on the order of weeks or months) after
placement of a fill, waves and currents will remold the material to an
equilibrium shape as determined by the grain size of the fill and the wave
conditions. Fine particles, if present, will move offshore and out of the
effective zone of longshore transport. Also, the berm of the initial fill may
be higher than that of the original and neighboring beach. In the initial
process of readjustment, therefore, the volume of the fill may decrease from

that which was initially emplaced. It is presently beyond the scope of

118

GENESIS to compute the volume of the fill remaining after the transient

readjustment period. The engineer operating GENESIS must judge conditions and
make an external calculation to estimate the average distance the shoreline
will advance after the fill has adjusted. (The fill volume per unit length of

beach after equilibrium has been established can be calculated by multiplying
the horizontal distance of berm advance, Line 1.8, by the vertical distance
from the berm crest, Line C.2, to the depth of closure, Line C.3, i.e.,

YADD(ABH+DCLOS) .)

1S)

FKKKKK KKH HHH KKH KKK HK KK KK HK KKK KKK KKK KKK KEKE KEKE ERER

* INPUT FILE START.DAT FOR GENESIS VERSION 2.0 *
SKK KE HHH HEHEHE KKK HK KE KEK KKK KKK KKH HK KK KK KKK KKK KEKE
Se ae a te alae So MODEL SETUP -\-==----2--2-=---- === 95-----o
.1 RUN TITLE
ILLUSTRATIVE EXAMPLE FOR MANUAL
.2. INPUT UNITS (METERS=1; FEET=2): ICONV
2
.3 TOTAL NUMBER OF CALCULATION CELLS AND CELL LENGTH: NN, DX
37 200
.4 GRID CELL NUMBER WHERE SIMULATION STARTS AND NUMBER OF CALCULATION
CELLS (N = -1 MEANS N = NN): ISSTART, N
i) sed
.5 VALUE OF TIME STEP IN HOURS: DT
12
.6 DATE WHEN SHORELINE SIMULATION STARTS
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501): SIMDATS
870101
.7 DATE WHEN SHORELINE SIMULATION ENDS OR TOTAL NUMBER OF TIME STEPS
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501): SIMDATE
870131
.8 NUMBER OF INTERMEDIATE PRINT-OUTS WANTED: NOUT
1
.9 DATES OR TIME STEPS OF INTERMEDIATE PRINT-OUTS
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501, NOUT VALUES): TOUT(I)
870115
.10 NUMBER OF CALCULATION CELLS IN OFFSHORE CONTOUR SMOOTHING WINDOW
(ISMOOTH = 0 MEANS NO SMOOTHING, ISMOOTH = N MEANS STRAIGHT LINE.
RECOMMENDED VALUE = 11): ISMOOTH

itil

.11 REPEATED WARNING MESSAGES (YES=1; NO=0): IRWM
il

.12 LONGSHORE SAND TRANSPORT CALIBRATION COEFFICIENTS: K1, K2
Wie 38

.13 PRINT-OUT OF THE TIME STEP NUMBERS? (YES=1, NO=0): IPRINT
1

---------- ee erre eee WAVES) --------------------------------B
.1 WAVE HEIGHT CHANGE FACTOR. WAVE ANGLE CHANGE FACTOR AND AMOUNT (DEG)
(NO CHANGE: HCNGF=1, ZCNGF=1, ZCNGA=0): HCNGF, ZCNGF, ZCNGA
ial 0)
.2 DEPTH OF OFFSHORE WAVE INPUT: DZ
60
.3 IS AN EXTERNAL WAVE MODEL BEING USED (YES=1; NO=0): NWD
0
.4 COMMENT: IF AN EXTERNAL WAVE MODEL IS NOT BEING USED, CONTINUE TO B.6
.5 NUMBER OF SHORELINE CALCULATION CELLS PER WAVE MODEL ELEMENT: ISPW
1
.6 VALUE OF TIME STEP IN WAVE DATA FILE IN HOURS (MUST BE AN EVEN MULTIPLE
OF, OR EQUAL TO DT): DTW
12
Figure 23. Example START file (Sheet 1 of 3)

120

.7 NUMBER OF WAVE COMPONENTS PER TIME STEP: NWAVES

at
.8 DATE WHEN WAVE FILE STARTS (FORMAT YYMMDD: 1 MAY 1992 = 920501): WDATS
870101
2 CSRS CSS SSS CSR BONO SCOR Ser ouS BEACH ela alore olen oi
.l1 EFFECTIVE GRAIN SIZE DIAMETER IN MILLIMETERS: D50
0.25
.2 AVERAGE BERM HEIGHT FROM MEAN WATER LEVEL: ABH
3
.3 CLOSURE DEPTH: DCLOS
15
SOSSSOS SESS ESS ROSS Con NONDIFFRACTING GROINS -------------------------D
.1 ANY NONDIFFRACTING GROINS? (NO=0, YES=1): INDG
1

.2 COMMENT: IF NO NONDIFFRACTING GROINS, CONTINUE TO E.
.3 NUMBER OF NONDIFFRACTING GROINS: NNDG

il
.4 GRID CELL NUMBERS OF NONDIFFRACTING GROINS (NNDG VALUES): IXNDG(1I)
15
.5 LENGTHS OF NONDIFFRACTING GROINS FROM X-AXIS (NNDG VALUES): YNDG(1)
200
2 OBC IID SOG DIFFRACTING (LONG) GROINS AND JETTIES -----------------E
.1 ANY DIFFRACTING GROINS OR JETTIES? (NO=0, YES=1): IDG
1

.2 COMMENT: IF NO DIFFRACTING GROINS, CONTINUE TO F.

.3 NUMBER OF DIFFRACTING GROINS/JETTIES: NDG

4 aah CELL NUMBERS OF DIFFRACTING GROINS/JETTIES (NDG VALUES): IXDG(1)
a) Peters OF DIFFRACTING GROINS/JETTIES FROM X-AXIS (NDG VALUES): YDG(I)
.6 SEP nis AT SEAWARD END OF DIFFRACTING GROINS/JETTIES(NDG VALUES): DDG(I)

wort rrr rrr scr cr rrr ee ALL GROINS/JETTIES ------------------------------F

.l. COMMENT: IF NO GROINS OR JETTIES, CONTINUE TO G.

.2 REPRESENTATIVE BOTTOM SLOPE NEAR GROINS: SLOPE2
0.062

.3 PERMEABILITIES OF ALL GROINS AND JETTIES (NNDG+NDG VALUES): PERM(L)
OROR a

-4 IF GROIN OR JETTY ON LEFT-HAND BOUNDARY, DISTANCE FROM SHORELINE
OUTSIDE GRID TO SEAWARD END OF GROIN OR JETTY: YG1

-5 IF GROIN OR JETTY ON RIGHT-HAND BOUNDARY, DISTANCE FROM SHORELINE
OUTSIDE GRID TO SEAWARD END OF GROIN OR JETTY: YGN

wr rrr rrr cr renee eee DETACHED BREAKWATERS --------------------------G
.l1 ANY DETACHED BREAKWATERS? (NO=0, YES=1): IDB

i
.2 COMMENT: IF NO DETACHED BREAKWATERS, CONTINUE TO H.

Figure 23. (Sheet 2 of 3)

121

G.3 NUMBER OF DETACHED BREAKWATERS: NDB
1
G.4 ANY DETACHED BREAKWATER ACROSS LEFT-HAND CALCULATION BOUNDARY
(NO=0, YES=1): IDB1
0
G.5 ANY DETACHED BREAKWATER ACROSS RIGHT-HAND CALCULATION BOUNDARY
(NO=0, YES=1): IDBN
0
G.6 GRID CELL NUMBERS OF TIPS OF DETACHED BREAKWATERS:
(2 * NDB - (IDB1+IDBN) VALUES): IXDB(I)
20 30
G.7 DISTANCES FROM X-AXIS TO TIPS OF DETACHED BREAKWATERS
(1 VALUE FOR EACH TIP SPECIFIED IN G.6): YDB(I)
450 450
G.8 DEPTHS AT DETACHED BREAKWATER TIPS (1 VALUE FOR EACH TIP
SPECIFIED IN G.6): DDB(I)

IES), dbs)
G.9 DETACHED BREAKWATER TRANSMISSION COEFFICIENTS (NDB VALUES): TRANDB(I)
0
SOS SS SSO OGG GS G5 COB Gaon ore SEAWALLS) -----------------52525-----5--- H
H.1 ANY SEAWALL ALONG THE SIMULATED SHORELINE? (YES=1; NO=0): ISW
il

H.2 COMMENT: IF NO SEAWALL, CONTINUE TO I.
H.3 GRID CELL NUMBERS OF START AND END OF SEAWALL (ISWEND = -1 MEANS
ISWEND = N): ISWBEG, ISWEND

5 16
ME RSS SS SS 0G CO SCC SR Ooo OG accr BEAGH (RIGGS eta yatote ait thi it I
I.1 ANY BEACH FILLS DURING SIMULATION PERIOD? (NO=0, YES=1): IBF

I.2 COMMENT: IF NO BEACH FILLS, CONTINUE TO K.
I.3 NUMBER OF BEACH FILLS DURING SIMULATION PERIOD: NBF
1
I.4 DATES OR TIME STEPS WHEN THE RESPECTIVE FILLS START
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501, NBF VALUES): BFDATS(1)
870101
I.5 DATES OR TIME STEPS WHEN THE RESPECTIVE FILLS END
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501, NBF VALUES): BFDATE(1)

870115

I.6 GRID CELL NUMBERS OF START OF RESPECTIVE FILLS (NBF VALUES): IBFS(I)
20

I.7 GRID CELL NUMBERS OF END OF RESPECTIVE FILLS (NBF VALUES): IBFE(T)
33

1.8 ADDED BERM WIDTHS AFTER ADJUSTMENT TO EQUILIBRIUM CONDITIONS
(NBF VALUES): YADD(1)
30
K-- 2-2-2 2-2-2 ee nee === COMMENTS --------------------------------- K
* COMMENTS AND VERSION UPDATE INFORMATION PLACED HERE
* ADVERTISING RATES AVAILABLE
eee ee END OF START.DAT -------------------------------

Figure 23. (Sheet 3 of 3)

122

291. The input file SHORL.DAT holds the position of the initial shore-
line, i.e., the shoreline used by GENESIS at the start of calculation. Ina
typical project, there will be at least three SHORL files, one each for the
calibration, the verification, and the project to be designed (present-day
shoreline position). Positions of the shoreline are given in the units
selected at Line A.2 of the START file and are measured from the baseline
(x-axis). A shoreline position must be given for each grid cell; i.e., there
must be NN calculation cells as entered at Line A.3 in the START file. An
example of a SHORL file is given in Figure 24.

292. If the modeler specifies at Line A.4 in the START file that only a
portion of the shoreline will be used in the simulation, then only that
segment of the shoreline between and including the boundary cells is loaded
from SHORL. However, shoreline positions must be given for the full range of
the calculation grid (NN points), as GENESIS will load positions of the
shoreline subsection with reference to the original, full grid.

293. Shoreline positions may be entered in "free format," i.e., with or
without a decimal. Individual entries must be separated by either a blank

space or a comma (or both) and placed in ascending order of grid cell number.

Exactly ten entries must be placed on each line, except for the last line.

PRK KKKKKK KKK KKK EKER ERK KERR ERE ERR EEE EKER REE RK ERE EERE EERE ERR RRE ERE ER

SHORELINE MEASURED AT SUNNY DAYS BEACH 1 JAN 1987.

DATA WERE TAKEN FROM DIGITIZED AERIAL PHOTO. DX = 300 FT.

KEKEKKEKKK KKK KEKE KERR ER REE EER ERK KER ERE RRR KK RE RRR REE RRR EKER RARE ERE ERE
1OO#0, 100.1, 100.2 100.3 100.4 100.6 100-7) 100.9 01.1 101-3.
MOG} y LO2, Ol 102239 “102.88 10323 1039) e104.55) | L052 3) dk Oen2 107-2
MOS3RNUOOsSweOs9s 11245 114.2 S16 Sl anl1823e 1120-68 (12351) 4112559
M2399 139.1 1135.6 (139.4) 143.4 147-8) “149.9

Figure 24. Example SHORL file

le)
oe
fe)
e

294. The input file SHORM.DAT holds the position of the measured
shoreline to be reproduced in the procedure of calibrating or verifying the
model. The format for SHORM is the same as for SHORL.DAT. Thus, positions of
the shoreline are given in the units selected at Line A.2 of the START file
and are measured from the baseline (x-axis). A shoreline position must be
given for each grid cell; i.e., there must be NN calculation cells as
entered at Line A.3 in the START file. An example of a SHORM file is given in
Figure 25.

295. GENESIS calculates a number called the "calibration/verification
error" (CVE) as the average of the absolute difference between the calculated
shoreline position (held in SHORC) and the measured shoreline position (held
in SHORM) at each grid point. This number conveniently summarizes in a single
value the degree of agreement between the calculated and measured shorelines.
The CVE should not be used as the sole criterion to judge the degree of fit
since a small value does not necessarily mean that the calculated and measured
shorelines are in close agreement along the entire calculated shoreline. As
an example, two shorelines may be in close agreement along most portions of
the beach but may be far apart along a small but very important section of the
beach. A small CVE value would not reveal this important discrepancy. Deter-
mination of the degree of fit is best done visually, which allows examination
of the overall fit.

296. If the modeler specified at Line A.4 in the START file that only a
portion of the shoreline will be used in the simulation, then only that
segment of the shoreline between and including the boundary cells is loaded
from SHORM. However, shoreline positions must be given for the full range of
the calculation grid (NN points), as GENESIS will load positions of the
shoreline subsection with reference to the original, full grid.

297. Shoreline positions may be entered in "free format," i.e., with or
without a decimal. Individual entries must be separated by either a blank

space or a comma (or both) and placed in ascending order of grid cell number.

Exactly ten entries must be placed on each line, except for the last line.

KRKKKK KKK KKK KEE KEKE KA KE KKK KKK KKK KEK EKER KKK KEK KEK RK EKER ERE EERE KERKERER ERR R

SHORELINE MEASURED AT SUNNY DAYS BEACH 1 JAN 1988.

DATA WERE TAKEN FROM DIGITIZED AERIAL PHOTO. DX = 300 FT.
KKKHA KAKA K KKK HHH HHA HH HHA HERE HH HHH KE KEKE EK KEK EEE KEE KEE EI K IEEIIE

HOORO, LOOK, TOOK2 LOOK4 OOS , 101 O08 TOL, 1O2Zk0> 10258 10355
MOS elO2s9* 1030") 1035" LOS 58) LO4t6s) lO4es 106.32 107204) W074
NOSHO MP LOON TD MOMS 2 LOS ea 1059 LOOLO LOO O336)) M0628) nO 92
PSS S56 13459. West 13835 14050) T4iet

Figure 25. Example SHORM file

298. The input file SEAWL.DAT holds the positions of one or more
seawalls or effective seawalls with respect to the baseline and specified in
the proper length units. An "effective" seawall might be a road or large
structure past which the shoreline is not expected to erode or be allowed to
erode. GENESIS prevents the shoreline from eroding landward of the position
of a seawall, whereas at reaches without seawalls the shoreline can retreat
essentially without limit. If a seawall is not specified, an effective
seawall is placed at -9999 m or ft (depending on units selected) by GENESIS,
and SEAWL is not read. If seawalls are specified along some sections of coast
but not others, the sections without seawalls should be similarly assigned a
distance of -9999 m or ft by the modeler. Figure 26 gives an example of a
SEAWL file.

299. Similar to the case of preparing a SHORL file, if a seawall was
specified to exist on the grid, the location of the seawall(s) (or -9999 for
each cell between seawalls) must be entered on the full calculation grid (NN
values), even if only a subsection of the grid will be modeled. Seawall
positions are entered at shoreline position points, i.e., at the centers of
grid cells.

300. Seawall positions alongshore may be entered in "free format,"
i.e., with or without a decimal. Individual entries must be separated by
either a blank space or a comma (or both) and placed in ascending order of

cell number. Exactly ten entries must be placed on each line, except for the

last line.

125

KEKKKK KKK KKK KKK KKK KKK HHH KH HHH KKK HA AK AK KKK KKK KEKE KEK KEKE REE EERE ERRERERERERER

SEAWALL LOCATION MEASURED AT SUNNY DAYS BEACH.

DATA WERE TAKEN FROM DIGITIZED AERIAL PHOTO. DX = 300 FT.
KKKKAAK KA KKK KKK KE KH K KKK KHAN KKK KH KK HHH KEKE KIKI KKK IEEE KEIR

-9999 -9999 -9999 -9999 100.0 100.0 100.0 100.0 100.0 100.0
100.0 100.0 100.0 100.0 100.0 100.0 -9999 -9999 -9999 -9999
-9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999
-9999 -9999 -9999 -9999 -9999 -9999 -9999

Figure 26. Example SEAWL file

DEPTH

301. The input file DEPTH.DAT is read if an external wave refraction
model has previously been run (NWD = 1 at Line B.3 in the START file) to
provide wave data. DEPTH holds depths along the nearshore reference line from
which GENESIS will continue to propagate waves using its own wave transforma-
tion routines (internal wave model). These depths had to be determined during
the process of running the external wave model, and the wave data held in
input file WAVES will bear a one-to-one correspondence with these depths in
order of grid cell number. If an external wave refraction model was not used,
i.e., wave parameters correspond to one depth (NWD = 0), this file will not be
read. A blank DEPTH file is given in Appendix B.

302. Depth positions alongshore may be entered in "free format," i.e.,
with or without a decimal. Individual entries must be separated by either a

blank space or a comma (or both) and placed in ascending order of grid cell

number. Ten entries must be placed on each line, except for the last line.

WAVES

303. The input file WAVES.DAT holds wave information that drives the
shoreline change simulation through calculation of the wave-induced longshore
sand transport rate. This file is read at every time step unless specified
otherwise at Line B.7 in the START file; it must exist and contain data in the

proper format to run GENESIS. Wave height is expressed in the user-specified

units as significant wave height. Wave angles are expressed in degrees, and
wave period is expressed in seconds.

304. The number of data lines contained in WAVES does not have to
correspond to the total number of calculation time steps. However, the WAVES
input file must be designed to provide the data at the specified time step.
WAVES is automatically rewound if the end of the file is reached, and wave
data are again read from the start of the file. A simple way to represent a
constant wave climate through time (for testing and scoping purposes, for
example) is to place only one line of data in WAVES. In this case, the
variable DTW at Line B.6 in the START file is recommended to be set equal to
or greater than the number of time steps to be used, as determined by the
values entered at Lines A.6 and A.7. Otherwise, the WAVES file will be
rewound numerous times, increasing required computer time.

305. NWD=1 .. If an external wave transformation model was used
(NWD = 1 in Line B.3 of the START file), at each time step WAVES must contain:

a. The wave period (assumed to be constant over the calculation
reach during the time step).

b. The wave height and wave direction at one offshore location
(at the depth DZ specified at Line B.2 of the START file).

c¢. The wave height and the wave direction for each point on the
nearshore depth reference line.

306. The three offshore quantities of wave period, height, and direc-
tion are placed on the same line and may be entered in "free format," i.e.,
with or without a decimal. Individual entries must be separated by either a
blank space or a comma (or both). If the period is negative, GENESIS will not
calculate for the particular time step. This capability is a convenient means
to represent a calm wave condition for which there will be no longshore sand
transport.

307. The total set of values of wave height and direction at each grid
point alongshore on the nearshore grid for each time step of the simulation
comprise a considerable amount of data. Therefore, these data are held in
"compressed format" in the WAVES file to minimize storage space. Thus, values
of individual pairs of wave height H and wave direction Z (called "6" in
the main text) at nearshore grid points are held in a quantity IZH and read

in the integer format 1017, in which IZH is calculated as

2H,

IZH = He10° + Ze°10 (42)

If the length unit is meters, H must be given to the nearest centimeter (in
the format F4.2), whereas if the length unit is feet, H must be given to the
nearest tenth of a foot (format F4.1).

308. The integer IZH will be converted to real numbers by GENESIS.
If the wave direction is negative, IZH should be given a negative sign.
Example 1: If ICONV = 1 (metric units selected at Line A.2 in the START
file), H= 2.18 m and Z= 10.7 deg will produce the value IZH = 218107
Example 2: If ICONV=1, H=1.14m and Z = -6.5 deg will produce the
value IZH = -114065

Example 3: If ICONV 2 (American customary units selected), H = 10.1 ft
and Z = 21.0 deg will produce the value IZH = 101210

309. It can be seen that the largest nearshore wave height that can be
entered depends on the units selected and is either 9.99 m or 99.9 ft, and the
largest magnitude of the wave angle is 99.9 deg. (If the wave refraction and
shoreline grids are parallel to each other, a wave approaching normal to the
shoreline will have an angle of 0 deg; therefore, the practical maximum
magnitude of the wave angle is 89.9 deg. Usually, wave angles will have much
smaller magnitudes. )

310. In summary, wave heights can be expressed to the nearest centi-
meter if metric units are used or to the nearest tenth of a foot if American
customary units are used. Wave direction can be specified to the nearest
tenth of a degree. The construction of WAVES files with data from an external
wave calculation is given in the GENESIS Workbook.

311. NWD=0 .. If NWD =O was entered in the START file, simple wave
refraction and shoaling algorithms contained in GENESIS will be used to bring
waves from the offshore depth specified at Line B.2 to breaking points along-
shore. This procedure will treat the local bottom contour as being straight
and parallel to the calculated offshore contour (see Part V). In this case,
for each time step, WAVES contains only the offshore wave period, height, and
direction in the format described above for the case of NWD = 1. Examples

of WAVES files with and without nearshore waves with only one wave component

128

(NWAVES = 1) are given in Figure 27. In Figure 27a each line corresponds to
one time step, whereas in Figure 27b one line with 3 values together with the
following four lines with 10 values each represent one time step. As shown,
it is possible to add descriptive information at the end of any line holding

the offshore wave period, height, and direction.

Output Files

312. As illustrated in Figure 22, the output from GENESIS is placed in
three files; SETUP.DAT, OUTPT.DAT, and SHORC.DAT.

SETUP

313. The output file SETUP.DAT is written both to screen and to a
logical file that can be sent to a printer for a hard copy. SETUP reads back
to the modeler basic information and instructions entered in the START file.
Also, error messages and warnings received from GENESIS are written to SETUP.
The SETUP information displayed on screen allows the modeler to review the
parameters governing the run and to terminate execution if an error is
detected in the START file. This measure helps to quickly identify computer
runs made on the basis of erroneous input information. The hard copy of SETUP
serves as documentation of the run and confirmation of the START file that
defined the run conditions.

314. As shown in Figure 28, the first line in the SETUP file after the
GENESIS logo gives the name of the run as specified on Line A.1 in the START
file. Units of measure and other important parameter values follow. With
regard to NTS , it should be noted that if the simulation interval spans a
leap year or years, the value of NTS will not initially account for the
extra day(s); however, as GENESIS steps through time if February 29th is
encountered, the counter NTS will be revised appropriately on the screen
(and for the calculation). The shoreline position and the change in shoreline
position from the original shoreline are written separately. The CVE para-
meter gives the average difference in position at each longshore grid cell
between the calculated shoreline SHORC and the shoreline SHORM that is to be

reproduced.

129

BAKKE AA KA AK EK KKK AAA KAKA KK KEKE KEK KEK KK EK KEKKEK EEK EKER EKER EERE EEK ERERREEERE

WAVES FOR ILLUSTRATIVE EXAMPLE FOR MANUAL.

FILE CONTAINS ONLY OFFSHORE WAVE DATA. DT = 6 HR. DX = 15 FT.
Shik nik eininink ik ok cok ek nik ink ek
.00 -30.0 JAN 1987

-00 00.0

PROP PRP RPRPENPEPENPRPRP HEHE
°
3°
°
°

NNYMWNHYHNYMWNHNMWNHDY WHY DH WD PND PO
SIS ©) CHOCO eye) ©) Cee) (St SITS) S)
oO
jo)
=
Nn
SriOiO (OLOLO Or Or Or Orr OuOe@

a. WAVES file without nearshore wave data

FR KKKEK ERE KK KEK EK EEK KEK KEK KKK HK KKKHKKKHKKKEREKKEEKKKKKEKSK IERIE RIKER III

WAVES FOR ILLUSTRATIVE EXAMPLE FOR MANUAL.
FILE CONTAINS OFFSHORE & NEARSHORE WAVE DATA. DT = 6 HR. DX = 15 FT.
RREKEEEK kkk kkk iiiiek ik iii bik ik kek kk

2.0 1.00 -30.0 JAN 1987
-114185-116203-118172-121160-123158-120155-172153-124121-102134-097119
-103122-113183-110201-127162-129167-125164-124146-154163-129199-112133
-124146 -154163-129199-112133-116203-118172-121160-123158-120155-172153
-124121-102134-097119-125164-124146 -154163-129199-112133-154163-129199
-112133-116203-118172-121160-123158-120155-172153

2.0 1.00 00.0
-114185-116203-118172-121160-123158-120155-172153-124121-102134-097119
-103122-113183-110201-127162-129167-125164-124146-154163-129199-112133
-124146-154163-129199-112133-116203-118172-121160-123158-120155-172153
-124121-102134-097119-125164-124146 -154163-129199-112133-154163-129199
-112133-116203-118172-121160-123158-120155-172153

2.0 1.00 00.0
-114185-116203-118172-121160.......

b. WAVES file with nearshore wave data

Figure 27. Example WAVES files

130

Gio AS TAL EON-G ION EE R i NG RE
&
LUND TNO Ue OF

KXKKK KREEKEKK ** ** KRAKKKKK *
KKEKEKEKE KKKKKKE ** * KREKKKK **
** ** ** KKK kK ** K*
** ** ** KKK KK ** **
** ** KKK KK ** **
** KKKKK KKKK HK KREKKK **
KK KK KEKKK Rk Kokkk Kee *
KK KK ** KK KKKK **

** ** ** Ke KKK ** k*
** ** ** xe kK ** **
KXKKKKK KEKKKKE ** ** KEKKKEKE kk
KeEKKK KREKEKKE ee ** Kk *
+---------------- +
| VERSION 2.0 |
+---------------- +

RUN: ILLUSTRATIVE EXAMPLE FOR MANUAL

AMERICAN CUSTOMARY UNITS

GROIN X-COORDINATES

5 15
DISTANCE TO GROIN TIPS FROM X-AXIS
230.0 200.0
GROIN PERMEABILITIES
0.0 heal
X-COORDINATES OF DETACHED BREAKWATER TIPS
20 30
DISTANCE TO BREAKWATER TIPS FROM X-AXIS
450.0 450.0
DETACHED BREAKWATER TRANSMISSION COEFFICIENT
0.0
DATES OR TIME STEPS WHEN FILLS START
870101
DATES OR TIME STEPS WHEN FILLS END
870115
X-COORDINATES WHERE FILLS START
20

SS EeAGRi GH
TECHNOL
KKK KEKE
ORE kk

** **

KKK **

KKK wk

** **

** we

** **
oe oe
KKK kK

)

GEN) TER

0G Y

KREEKE
KKKEKKK
** **
** **
**
KKKKKK

KKEKKKK

** **

K* **

KKEKKKKK
KKKKK

Figure 28. Example SETUP file (Continued)

iE S)ib

X-COORDINATES WHERE FILLS END
33

1 N= 37 NTS = 60
0 DZ =~ 60.0 D50)= 0725
0 Ka Olei7 K2 = 0.38

DX = 200.0 DT = 12.00 ISSTART =
NWAVES = 1 DCLOS = 15.0 ABH = 3)
HCNGF = 1.0 ZCNGF = 1.0 ZCNGA = 0.

SHORELINE POSITION AFTER 0O.YEARS = 60 TIME STEPS. DATE IS_ 870131
100/,0) 1101'-9) 10720) “12056 1100-0, 100)..0) 1000.2 100.0)" 100k0) 1000
LOO OM 10080) 1002) ANA 3) 10050, LO0NOs 90 OG a V6) SS Ere:
T4832) N45 eee laar 6 14525) UA 7Oe V4 89 ol Oued D581 SA oul Gre
P51 7 US 6y2heelSor 2) AO Td coos Ar ae ie Or

60 TIME STEPS. DATE IS 870131
-0.6 -0.7 -0.9 all gdl -1.3
-3.9 -14.4 -0.8 LOR, 30.2
32.8 S3r03) S352 31.4 20.8

SHORELINE CHANGE AFTER 0.YEARS

0.0 It) 6.8 2053 -0.
-1.6 -2.0 Soak 8.5

39/29 35 3357, 33)..0 32)
ay

'
Ww
CaoOwF |

22738 24.1 19.6 3: -0.4 0.0
OUTPUT LAST TIMESTEP NO. 60 DATE IS 870131
OFFSHORE WAVE DATA INPUT:
HZ = 1.00000 = 2.00000 ZZ = 0.000000
CALIBRATION/VERIFICATION ERROR = WI I221

CALCULATED VOLUMETRIC CHANGE = +5.03E+04 (YARDS3)
SIGN CONVENTION: "-" => EROSION, "+" => ACCRETION

Figure 28. (Concluded)

[e)
4
lac
tH

315. The file OUTPT.DAT holds the major output and calculation results
of the run. This information is printed to file automatically at the end of
the simulation period and at time step numbers specified in the START file
(Line A.9) by the user. OUTPT contains:

Run title and initial shoreline position from the x-axis.

In |p

Calculated shoreline position from the x-axis at the given
time steps.

Volume of sand transported alongshore at each grid cell,
expressed as a volume per unit time interval, i.e., per annum.

[er

Breaking wave height and direction at each point alongshore
calculated for each energy window.

132

Longshore sand transport rate at each point alongshore for the
last time step.

Calculated shoreline at the end of the calculation and
seawardmost and landwardmost shoreline positions during the
calculation period.

g. Calculated position of the representative contour. GENESIS
uses only the orientation of the line and not the absolute
position. For convenience, the line is placed 300 m (or the
corresponding distance in feet) seaward of the shoreline.

RUN: ILLUSTRATIVE EXAMPLE FOR MANUAL
INITIAL SHORELINE POSITION (FT)

LOOTOM LOO Te 10052) 100/135 1004; 100.6). 10027), 10059) (VO LOn.3
OMG eLO2Z OMe O20 35 02) 8) 10353) 103. 90455) 10553. 0652 (lon s2
HOS Sree LOD Sem LO Oa 2 ea 2 6) lS. S20); eel 2 Srl 2579
2G Oe 3S 2st S56) els Ora Aas 4 a7 8 wl 4on9

SHORELINE POSITION (FT) AFTER 29 TIME STEPS. DATE IS 870115
HOORO RS LOO RS 10220 > LLOsL L000) 100230). 1100.0 1002.0 1O0K0) 100::0
HOOROMLOOLO MOMS eal 2 1000). VOOFOR VOLO MOS ea 37/29
ES epee 2 7 Loa 0) 1456 147 95), T5001 153.73) 15453) Sie 7
56) OM 160)6 1606 1446 14401 14720) 14929

LAST TIME STEP. WAVES ORIGINATING FROM WINDOW NO. 1
BREAKING WAVE HEIGHT

O3917 0.97 0.97 0.97 O97 O200'5, JO500% 10/200 910/300) 10)00
OR OO O00 2020055203005) 20/5005) 0200, 10200-51000) 20200 0.00
OFOOR O00) 10500) s0.005 -..0::00) | 0500) {0/00) | £000) FR000 | 0700
OF00 5530.00, 0500 5.0.00 0:00 O700, 0500

BREAKING WAVE ANGLE TO X-AXIS
0.05 0.05 ORLO |, 10525 O502> (0005) 205100) % 70/3005) 20100 0.00
OS00 mee 000 t 0500 7) 10300 5 000s 0500) 000% 000" 2 e0'..00 0.00
OFOOR O00 R 0 005 28000 seOn00r FOOOM EO OOM OR OOM RO 008 20500
O2005 0.00/74 20)300)9 (0300710500) “0300 (0200

LAST TIME STEP. WAVES ORIGINATING FROM WINDOW NO. 2

BREAKING WAVE HEIGHT
OO0NN BO100%, 10/00 % 10/300) = 105,96 O594 Ss 1095 O95 0295 0.95
0.95 0.95 0.95 0.95 O95 OSS O94 Ono 0.87 0.68
0.41 0.28 OR 2S es OF ZOOM ROR LS: ae Op ah: 0.17 0.16 0.16 gals)
OFa'S (0) as) ORS OU OAS sn} Orel 4:

BREAKING WAVE ANGLE TO X-AXIS
OF005 40/500 ® 0:00) 5 40:00) = (0102 0.02 0.02 0.02 0.03 0.03
O04 OROLS us (O05) 02728 0.07 0.07 .-0.14 ~ 0543 0.47 2)
NOOR Ga elo lON ll S220 tell oral Ole A299 eeli5 = OO} 5).2'5) ie 13)66) pl 70
My 21 SOO 337 855 el 281k a3 82) ige9

Figure 29. Example OUTPT file (Sheet 1 of 3)

133

LAST TIME STEP. WAVES ORIGINATING FROM WINDOW NO. 3
BREAKING WAVE HEIGHT
0.00 0.00 O00 OOO N) (Oa OMA LOL G sO pel Gee Ofelia OF ence
OSTA OTA ORAS Oj 0.15 0.15 (O)sILSy) abs) OFS 0.16
0.16 0.16 (0)gak7/ 0.17 0.18 OF 20m OF 23 0.28 0.41 0.69
0.88 0.93 0.95 0.95 O95 0.96 0.96
BREAKING WAVE ANGLE TO X-AXIS
0.00 0.00 0.00, -0.00) OF02 -13739 135426 =13).445 -13547 -13250
=13- 53613457135 59y-1 02465 1359-3), 6m i On oer OOD ena| Oho 9 maSeam
~111.12 -14.99 -14.49 -14.28 -14.36 -14.51 -14.60°-14°23 -12.98 a4
0.43 OF40) O31 0.21 0.28 0.35 0.38
GROSS TRANSPORT VOLUME (YARDS3) FOR CALCULATED PART OF YEAR 87
4925 4925 4871 4679 0 4607 4845 4897 4912 4918
4924 4917 4873 4662 458 4826 p55) 34630") (4.252 2713
2240 1208 746 556 469 435 446 545 913 795
2610 3847 4547 5992 4928 4691 4723 4723
NET TRANSPORT VOLUME (YARDS3) FOR CALCULATED PART OF YEAR 87
3867 3867 3619 2704 0 By 132 225 346 492
666 880 1146 1420 299 739 1260 3171 3276 1847
2A 1074 598 390 274 190 102 -49 -454 -344
Taby/al 2421 3494 5168 3875 3477 3530 3530
TRANSPORT VOLUME TO THE LEFT (YARDS3) FOR CALCULATED PART OF YEAR 87
-529 -529 -625 -987 0 -521 -525 -525 -527 -526
-524 -527 -552 -1025 -94 -511 -482 -729 -488 -433
-62 -66 -73 -83 -97 -122 -171 -297 -683 -569
-719 -712 -526 -412 -526 - 606 -596 -596
TRANSPORT VOLUME TO THE RIGHT (YARDS3) FOR CALCULATED PART OF YEAR 87
4396 4396 4245 3691 O° 4086 4319 4372 4384 4392
4400 4389 4320 3636 BS) ASUS Tn AGS 7/5) 3900 3764 2280
2A, 1141 672 473 371 Sl 274 248 229 225
1890 31347) 4021 5580 4402 4084 4126 4126
OUTPUT OF BREAKING WAVE STATISTICS FOR SELECTED LOCATIONS
N.B. WAVE DIFFRACTION IS NOT ACCOUNTED FOR!
GRID CELL NUMBERS
i 2 3 4 5 6 7 8 9 10
ital 12 13 14 15 16 17 18 19 20
20 22 23 24 25 26 27 28 29 30
Sil! 32 33 34 35 36 37,
AVERAGE UNDIFFRACTED BREAKING WAVE HEIGHTS (FT).
Mo S72 io 67 a2 2 We eed: 1.2 12
Ie WZ te? Mae W522 12 ee We 2 1.2 se
12 Wer i672 Ibe S22 io? a2 Lie oe 1.2
G72 G2 Ler. a2 Ie? G2. 2

Figure 29. (Sheet 2 of 3)

134

AVERAGE UNDIFFRACTED BREAKING WAVE ANGLE TO SHORELINE (DEG)
Ibe alt eal 0.7 -0.9 13 1.4 13 ies) eS 13
eS. 13 1.2 -0.9 Ded 3 Ibe’, -0.3 -0.4 -4.2
-0.1 nz 43 Gal Aleit 1.0 0.9 0.6 yee3 2.4
0.4 0.4 1.5 4.4 1.7 0.9 0.9
AVERAGE LONGSHORE TRANSPORT RATE BASED ON UNDIFFRACTED WAVES (FT3/SEC)
0.04 0.04 0.04 £40.03 0.04 0.04 0.04 0.04 0.04 £40.04
OFO4= 10204 70:04 O08! “O04 O04) (O04 1.0203 0.03 0.00
0.03 ORO4 Pe OR04, 7 O204 0504. 0048 SN O04) BOR O4S O04. 707105
0:04 0.04 0.04 0.06 0.04 0.04 0.04
LONGSHORE TRANSPORT (FT3/SEC)
0.00 0.00 0.00 -0.01 0.00 0.00 0.00 0.00 £0.00 0.00
0.00 0.00 0.00 -0.01 0.00 0.00 0.00 -0.01 -0.01 -0.01
OF00F OF 00)2 0200 . 10)..00',, 0200) 0200), 000 10200), -0.,01 0.00
0200, 0500 20:00; 0.01, 0.00; (0:00) 0:00) 0:00
CALCULATED FINAL SHORELINE POSITION (FT)
NOOO, UOMO O70) 1206 LOON0) 1000) TO00. 10050) 7 10050. 1000
HOO LOR LOOLON LOOK 2* Wil SOOO SPO OMOF 90 Me l04G0 Ss 116 9F S754
ACA oi2 AGG AS os a7 0) a8 9 oi6) 155282 54 5. 467
eV LD 62, la Si2) AO N64 Ta a re 9)219
CALCULATED SEAWARDMOST SHORELINE POSITION (FT)
NOOR OM OTS SLOVO) 20F 8 TOG LOOnG. LOOK OOS: =AOlwy mols
OMG AO 220" MO28= a 2525 O43 LOS 79 MOS AOS 4 Gr 9 ss 13858
Ore 2 SO MAA Gry 45) 5 AV Ole La8 290 oA6) 5/8) 155.245) 152558
Sy eaG 16) ONES | aOR VAG 4 47 ee e499
CALCULATED LANDWARDMOST SHORELINE POSITION (FT)
100.0 100.1 100.1 998 2) 10030) 1000s LOO 0) L000 1O0n0%, 100.0
LOOZOM VOOROY LOO) SP eats 7 10020) 1000s 90S ON 0425 OSe 7, 072
WO ssh WO esi EOE abe ey ese seul alee sh AO Gy alas heal 9 aly2o ye
U287 9.8 1320 135-16 1394 W434 1470)" W499
CALCULATED REPRESENTATIVE OFFSHORE CONTOUR POSITION (FT)
1084.3 1084.4 1084.6 1084.7 1084.9 1085.0 1085.2 1085.5 1085.7 1086.0
1086.4 1086.8 1087.2 1087.7 1088.3 1089.0 1089.8 1090.6 1091.6 1092.7
1093759 11109532 1096-8 d098i5) 1100.3 1102 3 110455) 110659 AMO9NS 2.2

TAUB dk ALISO IIR) MeL) A275 7) AROS S) ILLS ye

CALIBRATION/VERIFICATION ERROR =

79220

CALCULATED VOLUMETRIC CHANGE = +5.03E+04 (YARDS3)

SIGN CONVENTION:

"." => EROSION,

Figure

+" => ACCRETION

29. (Sheet 3 of 3)

135

SHORG

316. The output file SHORC.DAT holds the "final" calculated position of
the shoreline, i.e., the position of the shoreline at the last time step
(SIMDATE at Line A.7 in the START file). The format of SHORC.DAT is such that
the file can be copied to an input SHORL file holding the "initial" shoreline
corresponding to the next stage of a simulation. This file is useful if the
configurations of structures change over the course of the simulation period,
as described Part V. The objective fitting criterion, quantified by the para-
meter Yaiss , is determined by comparing the calculated final shoreline
location held in SHORC.DAT with the measured final shoreline location held in
SHORM.DAT. The variable Ygir¢ expresses the mean difference in location

between the calculated final shoreline and the corresponding measured one.

Error and Warning Messages

317. After all needed input files are prepared and available to be
called by GENESIS, the program can be run. At the beginning of use of the
model on a project, it is not uncommon and should not be unexpected to have
data mismatch errors, particularly in the START file. GENESIS provides a
number of error and warning messages that give the user recovery information
for the more common mistakes and notification of potentially undesirable
conditions encountered during a simulation. These messages are printed to
screen and to the output file SETUP. Error and warning messages and suggested
recovery procedures are given in Appendix C.

318. One strategy that has been found useful for reducing errors is to
introduce project complexity in the START file in stages, testing (running)
the model for a few time steps at each stage. For example, if the project has
several structures and beach fills, the START file would first be constructed
with only the boundary conditions and tested. Next, perhaps only nondiffract-
ing groins would be placed on the internal grid, if there are such structures.
Then, diffracting structures would be introduced. Finally, after successful
testing at each stage, the beach fills would be placed in the START file. In

this way, errors can be more easily isolated.

136

Error messages

319. An error message gives information about a "fatal" error, that is,
an error detected that would stop the calculation. On the data entry level,
these errors might be caused by inconsistencies in specified quantities (for
example, specifying three groins but only giving positions for two) or a
serious problem in the calculation (for example, running many high waves at
extremely oblique incident wave angles). GENESIS is based on physical
assumptions and calculation techniques that have limitations (as described in
Part V). If these limitations are exceeded, the simulation may fail or give
an erroneous result. Experience with GENESIS in a variety of projects
indicates it will perform satisfactorily if prudence is taken to represent

realistic wave, structure, and shoreline position conditions.

Warnings

320. Warnings are given if a potentially undesirable condition is
detected in the course of calculation. One of the more common warnings is
that the stability parameter STAB (called "R," in the main text) has
exceeded the value of 5.0 during a particular time step (see Part V). If
STAB > 5.0 for too many time steps (as judged by the user) or if a number of
STAB values are very large, the calculation is likely to be numerically inac-
curate. In this case, the time interval DT should be decreased. The
exception to this discussion of STAB is use of GENESIS in scoping or preli-
minary analysis, for which results need only be qualitative and where large

time steps may be desirable to reduce computation time.

13/7

PART VII: REPRESENTATION OF STRUCTURES AND BEACH FILL

Types of Structures and Their Effects

321. GENESIS simulates the effects of common coastal structures and
engineering activities on the shoreline position. Generic types of structures
that can be represented are groins, jetties, harbor breakwaters (with respect
to their functioning as a jetty or groin); detached breakwaters; seawalls; and
the "soft structure" of beach fill. Considerable flexibility is allowed in
combining these basic structures to produce more complex configurations, e.g.,
T-shaped groins, Y-shaped and half-Y groins, and jetties with spurs. Combina-
tions of these types of structures are also possible.

322. In shoreline change modeling, structures exert two direct effects:

a. Structures that extend into the surf zone block a portion or
all of the sand moving alongshore on their updrift sides and
reduce the sand supply on their downdrift sides. Blocking can
be direct, as by a groin or jetty, or indirect, as by the
calmer region of water in the formed lee of a detached
breakwater.

Detached breakwaters and structures with seaward ends extend-
ing well beyond the surf zone produce wave diffraction. The
diffraction pattern causes the local wave height and direction
to change, altering the longshore sand transport rate.

Grid Cells and Numbers of Structures

323. For design mode modeling, it is recommended that at least nine
grid points (eight cells) be placed behind detached breakwaters and between
adjacent groins. In a scoping mode application or if a wide coastal extent is
being covered for which detail at any one structure is not vital, it is recom-
mended that at least four cells be used.

324. Grid spacing in the modeling system should be selected through a

balance of the following four conditions:

a. Resolution desired.
b. Accuracy of measured shoreline positions and other data.
c. Expected reliability of the prediction (which mainly depends

on the verification and quality of input wave data).

d. Computer execution time (which depends on the time step,
number of cells on the grid, and the simulation interval).

325. The number of structures that can be included in the model depends
on the particular configuration of GENESIS which was loaded on the operating
system. The configuration was determined on the basis of hardware and
software limitations and the intended use. The maximum numbers of grid cells

and structures that can be expected in GENESIS Version 2.0 are:

avanGridecell'sisy e600:

b. Groins (total of nondiffracting and diffracting): 70.
c. Detached breakwaters: 20.

d. Beach fills: 50. x

It should be remembered that execution time increases substantially as the

number of diffracting structures increases.

Representation of Structures

326. This section describes capabilities and limitations in represent-
ing structures in GENESIS. Idealized examples of plan views of various
configurations and the appropriate section of the associated START file are
given for reference. The theory of "wave energy windows" and "transport

calculation domains,"

through which GENESIS operates in representing the
effects of most types of structures, is given in Part V. It is again noted
that structures are represented as infinitesimally thin objects in the model.
For example, a groin or jetty is located at the wall of a single cell and
cannot occupy the position of more than one wall.

327. Four basic rules governing placement of structures are:

a. The position of a structure is defined by the location of its
tip(s), and these positions are located at cell walls.

b. If a lateral boundary (at either cell wall 1 or cell wall
N+1) is not explicitly specified to be a groin, GENESIS will
apply a pinned-beach boundary condition as a default.

c. There must be at least two cells between groins. As an impor-
tant special case, a groin cannot be placed in the cell next
to a lateral boundary.

d. The locations of the tips of diffracting structures can

coincide (be at the same longshore coordinate), but they
cannot overlap.

Legal positioning of structures
328. Figure 30 gives examples of legal placement of structures.

Nondiffracting groins may be placed behind a diffracting breakwater (but
diffracting groins cannot) (upper left sketch). The other three sketches in
this figure show situations involving the tips of two structures sharing the
same grid cell. The tip of a detached breakwater and a diffracting groin can
be at the same longshore grid cell, as can the tips of two detached break-
waters. The tips of one or two detached breakwaters can be located in the
same cell and at the same distance offshore as the tip of a groin to form an
angled structure such as a spur groin, Y-groin, angled groin, etc. These
types of legal patterns of structures may be repeated along the model reach,

as required.

y NONDIFFRACTING GROINS TIPS OF ONE DIFFRACTING
BEHIND DETACHED BREAKWATER GROIN AND ONE BREAKWATER
IN SAME CELL

CZZZZ2

DISTANCE OFFSHORE

y TIPS OF TWO BREAKWATERS TIPS OF JETTY AND BREAKWATER
IN SAME CELL IN SAME CELL

x
DISTANCE ALONGSHORE

Figure 30. Example legal structure placements

140

Illegal positioning of structures
329. Figure 31 illustrates the major restrictions on placement of

structures. Groins must be placed at least two grid cells apart (upper left
sketch). (Since groins in the field are typically placed one to two groin
lengths apart, this is not a serious limitation.) A groin cannot be placed in
the cell adjacent to a boundary cell, whether the boundary is a groin or a
pinned beach (upper right sketch). Diffracting structures of any type cannot

overlap (lower left and lower right) (except at their tips; Figure 30).

GROINS SEPARATED BY
LESS THAN TWO CELLS

GROINS PLACED NEXT
TO A LATERAL BOUNDARY

ADJOINING CELLS

PINNED BEACH
GROIN AT AT N+1

ONE CELL

24 25 27 V2 N N+1

DISTANCE OFFSHORE

DIFFRACTING GROIN BEHIND
A BREAKWATER TIPS OF BREAKWATERS OVERLAP

(SSS

x x
DISTANCE ALONGSHORE/GRID CELL NUMBER

Figure 31. Example illegal structure placements

141

330. Detached breakwaters. Figure 32 illustrates detached breakwater
parameters that may be varied. Detached breakwaters are defined in the
modeling system by specifying pairs of ends or tips of the structures in the
START file section. (Wave transmission coefficients must also be given.) As
a summary, as long as detached breakwaters do not overlap (except for two tips
having the same grid cell), the modeler is free to vary the length, trans-
mission coefficient, orientation, distance offshore, and, in the case of
segmented breakwaters, the gap width between structures. Detached breakwaters
or their equivalent, such as a portion of a harbor jetty, may cross a grid
boundary, although this is an unusual and complex case and should be modeled
with caution. A groin cannot be placed at the boundary if a detached break-
water crosses it. GENESIS Version 2 will not allow the shoreline to grow to
meet a detached breakwater (tombolo formation not simulated). If the shore-

line approaches very close to a detached breakwater, the model will fail.

MULTIPLE DETACHED BREAKWATERS

LENGTH ARBITRARY

GAP WIDTH ORIENTATION TWO TIPS AT
ARBITRARY ARBITRARY ee SAME CELL

LLL.
\ | LEA

Ze 2

AS YY’

S PAGaaisision

Yy
RG BREAKWATER

ACROSS BOUNDARY

DISTANCE OFFSHORE

1 10 24 30 35 50 66 N+1 x
DISTANCE ALONGSHORE/GRID CELL NUMBER

Figure 32. Parameters associated with detached breakwaters

142

331. Groins.

Figure 33 illustrates various legal representations of

groins. Simple groins can have arbitrary lengths and are aligned parallel to

the y-axis by GENESIS; i.e., angled groins cannot be directly modeled. Groins

are assumed to extend a distance landward of -9999 m or ft from the x-axis. A

groin cannot be flanked on its landward end; i.e., it cannot be isolated in

the surf zone. However, groins can be covered by sand, as may occur during a

beach fill; if uncovered by wave action, they will resume functioning.

DISTANCE OFFSHORE

ie Y/GROIN AT i=1 OR i=N+1

GROINS WITH DIFFERENT
LENGTHS AND PERMEABILITIES GROINS BURIED

BY BEACH FILL

eG.
10 20 30 44 N+1
DISTANCE ALONGSHORE/GRID CELL NUMBER

Figure 33. Legal placement of simple groins

Complex Groin Configurations

332. Complex groin or jetty configurations, such as Y-groins, T-groins,

and spur jetties, can be represented by placing tips of diffracting groins and

detached breakwaters together. Figure 34 shows examples of complex structure

configurations that may be represented, and Table 3 shows the corresponding

values defining these configurations in the START file.

143

DISTANCE OFFSHORE (m)

age a MODELED

45 50 56

250 DIFFRACTING GROIN WITH SPUR

ANGLED JETTY

200

MODELED

150
100

97 100
DISTANCE ALONGSHORE/GRID CELL NUMBER

Figure 34. Examples of complex groin and jetty configurations

333%

Several features in the examples in Figure 34 deserve attention:

At locations where structures are attached, IX , Y , and D-
type variables must be identical. If not, GENESIS will not
recognize the structures as being connected.

The top of the "T" forming a T-groin (such as in example c)
must be represented by two structures, each attaching to the
diffracting groin. Otherwise, the configuration would be
illegal (overlap of diffracting structures) as shown in Figure
Sil

The connection between two detached breakwaters must be at the
exact same point in all specifications (as in example c).

All groins attaching to detached breakwaters must be repre-
sented as diffracting.

144

Table 3
Example Inputs for Complex Structure Configurations in START.DAT*

Diffracting Groin

Variable Spur Groin (a) T-Groin (b) Angled Jetty (c) with Spur (d)

IDG 1 1 1 1
NDG 1 1 i 1
DDGCL) | 1 50 100 25
YDG(1) 350 135 410 225
DDGOL)7 3.1 250 35 57)
GIs 120 - - -

YGN*™” - - 630 -

IDB 1 iL 1 1

NDB 1 2 iL 1
PXDBGE). @ 1 12 Bs 0}) GO) BE 97 100 25m) 311
YDB(I) 350 400 1351913501135 0035 410 410 2255135
DDBGM) ie euSedh 325 Te 8in2 0220 2453 SVT) S55) eae lye}

* See Figure 34.
** Values chosen arbitrarily.

Seawalls

334. Effective sections of seawalls may be defined anywhere on the
grid. If several seawall segments are present along the beach, they will be
represented by a single seawall separated by areas with locations put at
-9999 m or ft (depending on the units chosen) on sections of the beach not
protected by a seawall. Figure 35 and the tabulation that follows demonstrate
how two short seawall segments are represented in GENESIS. It is noted that
the seawall does not need to be straight but may form a "curve" to follow the
trend of the beach contours. This is common in placement of a rubble mound,
which may be represented as a seawall. The following tabulation gives the

y-values in a SEAWL.DAT file designed to describe two seawalls:

145

-9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 60

59 58 Dy) 56 BP) 54 D3 52 51 50
-9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 10
10 10 10 10 10; -9999) =9999) 71-9999) 1-9.999)4))-9999

100

Bo - SHORELINE

SEAWALL

DISTANCE OFFSHORE (M)

SEAWALL
20

10 20 30 35 40
DISTANCE ALONGSHORE/GRID CELL NUMBER

Figure 35. Example illustrating simple seawall configuration

Beach Fills

335. Beach fills may be placed anywhere on the beach and can overlap in
time and position. The beach is advanced an equal amount daily at each cell
where a given fill has been defined. Beach fills can cover groins, and, if

the beach erodes, the groins will become uncovered and begin functioning.

146

336. The corresponding variable values in START.DAT representing the
examples of the beach fills in Figure 36 are:

IBF: 1
NBF: 3
BFDATS(1I): 890101 890101 890615
BFDATE(I): 890228 890228 890715

IBFS(I): iL 10 20
IBFE(I): 30 20 60
YADD(T): 20 5) 5

40 BEACH FILL
rics 01 JAN — 28 FEB 1989
S
i
oa” tg pate
f To ~ Bexcn ALL
ro) 15 JUN — 15 JUL 1989
lJ
2 20
b
a
10

ORIGINAL SHORELINE

10 20 30 40 50
DISTANCE ALONGSHORE/GRID CELL NUMBER

Figure 36. Example illustrating simple beach-fill configuration

337. As an alternative to representing the first fill by a 20-m fill
from grid cell 1 to grid cell 30 superimposed by a 10-m fill from grid cell 10
to grid cell 20, it can also be represented by three attaching fills. The
alternative values in START.DAT would then be:

IBF: 1
NBF: 4
BFDATS(1I): 890101 890101 890101 890615
BFDATE(1): 890228 890228 890228 890715

IBFS(I1): al 10 20 20
IBFE(I): 10 20 30 60
YADD(1): 20 25 20 5

147

338. It should be noted that all values in a column must refer to the
same fill. This means that the values on a row may not always appear in

consecutive or chronological order.

Time-Varying Structure Configurations

339. In many modeling projects, structures are built, modified,
removed, or destroyed during the course of a shoreline change simulation
period. The simulation must be performed in stages in such a case. A START
file with the initial configuration would run GENESIS until the time step of
the change in a structure; the SHORC file (calculated shoreline) from this
first stage would then be copied to a SHORL file (initial shoreline) for the
next stage of the simulation, and another START file describing the new
configuration would be used to continue. This procedure can be chained for
describing any number of modifications in structure configurations and boun-
dary conditions. Most computer systems allow creation of a batch file to

automate the chaining of calculation segments.

148

PART VIII: CASE STUDY OF LAKEVIEW PARK, LORAIN, OHIO

Background

340. This chapter presents a case study that exercises GENESIS and the
skill of the modeler in a realistic way for an actual project. The project,
Lakeview Park, is located on the southeast shore of Lake Erie, in Lorain, Ohio
(Figure 37). The park lies about one-half mile west of Lorain Harbor, a
prominent feature along the coast that includes breakwaters extending lakeward
almost a mile from shore. This coast has a limited source of beach sand and
consists of eroding glacial till bluffs, narrow pocket beaches, and armored
stretches with no beach at all. Under these conditions the municipality of
Lorain wished to protect the existing park and provide a recreational beach.

341. Documentation on the Lakeview Park project is substantial, but
wave information is lacking and had to be synthesized by the modelers through
use of a wave hindcast and limited gage data. The project is sufficiently
localized and simple to be encompassed in an illustrative case study without
excessive detail and demands on computer resources, yet it highlights many
features of GENESIS. The case study was performed for instructional purposes
and not for design, with expedients taken to reduce the level of effort.

342. The project and monitoring results have been well documented.
Authoritative and complete information on the project design and both local
and regional coastal and geologic processes is contained in the General Design
Memorandum (GDM) for the project (US Army Engineer District (USAED), Buffalo
1975). Walker, Clark, and Pope (1980) summarize the purpose and setting,
regional and local coastal and geologic processes, design procedure for the
project, and results of early monitoring. Pope and Rowen (1983) report
results of a 5-year monitoring program at the site, evaluating project
performance through calculation of sand volume and shoreline position change.
These studies provide considerable information on waves and water levels,
storms, geology, and sand transport in the region and at the project, furnish-

ing the necessary "coastal experience" for the case study. The information

149

CANADA

MICHIGAN

NEW YORK

TOLEDO

ae Be Si cite
PROJECT \LORAN/

SITE
OHIO

CLEVELAND

UNITED STATES

a. Location map

LAKEVIEW PARK

DEPTHS IN FEET BELOW
LOW WATER DATUM.

b. Planview detail

Figure 37. Location map for Lorain, Ohio

150

these three studies contain is selectively summarized here so that the reader
can understand the modeling procedures in context. Most of the background
material in this chapter was derived from the three studies.

343. Maintenance of a stable beach in a coastal environment such as at
Lorain would require placement of fill and periodic renourishment. However, a
small beach fill would be rapidly depleted by longshore transport, suggesting
that the constructed beach should be enclosed by groins. Groins will have
minor impact on the neighboring shore, since there is effectively no sand
moving along the coast and no neighboring beaches to protect. The cross-shore
component of sand transport must also be considered. The wave climate in the
Great Lakes is dominated by short-period high waves generated over narrow
fetches by frequent small storms. The resultant steep storm waves tend to
transport sand offshore, and there is no completely compensating counterpart
of persistent long-period swell waves of summer which tend to transport sand
onshore, as is the case on an open coast facing an unlimited ocean fetch.
Since the coast is deficient in sediment, sand moved offshore tends to
disperse and does not return to the original location. It is logical to think
of protecting the fill with detached breakwaters to reduce wave energy
arriving to the beach and to prevent sand from moving offshore.

344. Such a project was constructed at Lakeview Park in October 1977
(Walker, Clark, and Pope 1980; Pope and Rowen 1983) and was the first detached
breakwater system specifically built in the United States to stabilize a
recreational beach (Dally and Pope 1986). Figure 38 is an aerial photograph
of the site.

345. The net direction of regional longshore sand transport along this
coast tends to be from east to west, as may be inferred from the lengths of
fetches in Figure 37, with an annual potential rate estimated to be about
60,000 cu yd. However, due to sheltering of easterly waves by the Lorain
Harbor breakwaters, the potential net transport rate at Lakeview Park is from
west to east at an estimated 21,500 cu yd per year, but with an actual
transport rate of only 5,000 to 8,000 cu yd per year due to lack of sediment.
Because of the limited natural supply of beach sand, the coast has suffered

from chronic erosion, and, for portions of the unprotected coastline, erosion

TS:

W17-74

Figure 38. Aerial view of Lakeview Park, 17 November 1979

continued during recent high lake levels which lasted from the early 1970's
through the monitoring period. Lake level peaked in 1973 and again in 1986.
346. In earlier attempts to protect private and public property, groins
and a seawall were built and repeatedly repaired with only limited success to
halt shore erosion. Storm waves and high lake levels during the 1970's
damaged the coast, and the seawall protecting Lakeview Park with its bathhouse

was undermined and collapsed.

Existing Project

347. To meet the project goals, a plan that included a beach fill,
groins, and detached breakwaters was developed in 1974 in a l-year study that
did not involve use of either mathematical or hydraulic models, leading to a
comprehensive GDM (USAED, Buffalo 1975). The project was completed in October
1977, and a 5-year monitoring program was begun. The fill was designed to

protect the park and serve as a recreational beach; the detached breakwaters

152

and groins were designed to protect the fill. The project has been a success;
the beach is effectively stable, and the rate of replenishment during the
first 5 years after completion of the project in October 1977 was only

approximately 35 percent of the predicted.

Structures and beach fill

348. As shown in Figure 39, the project consists of three rubble-mound
detached breakwaters and two groins that contain a sandy beach created by a
fill. Since the project was designed in American customary units, those units
were selected in the modeling and are used in the following discussion. The
length of the beach, defined by the distance between groins, is 1,250 ft, and
the nominal distance from the revetment at the park to the breakwaters is
500 ft. The breakwaters are 250 ft long and separated by 160-ft gaps. Water
depth at the breakwaters is about 10 to 13 ft, depending on lake level. The
breakwaters have a crest height of 6 ft above the long-term average lake
level. The western groin, made of concrete, is 164 ft long, and the eastern,
composite concrete and rubble-mound groin is 360 ft long and is intended to
prevent sand from leaving the project. Except for a small groin compartment
on the west side of the project, the neighboring shore is almost devoid of a
subaqueous beach.

349. The initial beachfill volume was 110,000 cu yd and had a +8-ft
berm elevation. After placement of the fill, the beach near the west groin
eroded, and this area was replenished with 6,000 cu yd in July 1980 and
another 3,000 cu yd in September 1981. However, the overall fill was surpris-
ingly stable and even experienced a slight volume gain of about 3,000 cu yd
per year (excluding the two extra fills) over the 5-year monitoring program.
In design of the project, the annual loss was predicted to be 5,000 cu yd,
representing 5 percent of the initial fill volume. The project has clearly
satisfied the two design criteria of protecting the park and providing a
recreational beach facility. Aerial photographs indicate that the project has

minimal impact on the neighboring shore.

153

LAKE ERIE

EAST GROIN

LWD_SHOREUNE
WEST asia pat en
ee

BASE LINE

STA. 10 + 00

SCALE

DATUM: LWD = 568.6 FT
STATIONS IN 100—FT O 100 200 300 FT

INCREMENTS. ——

Figure 39. Project design, Lakeview Park

Sediment

350. The native beach material was characterized as being composed of
fine, well-sorted quartz sand, whereas the fill material was coarser (medium-
fine), consisting of only 50-percent quartz grains and much more poorly
sorted. The fill material was found to predominate in the area landward of
the detached breakwaters after completion of the project. Samples indicated
that the bottom out to 300 ft offshore consists of medium to coarse sand with
gravel.

351. Repeated sediment sampling during the 5 years following the
initial beach placement indicated that native sand is entering the west side
of the project site, and sand is moving out of the site at a lower rate across
the eastern boundary. There was no indication of sand being transported

offshore between the detached breakwaters.

154

Water level and shoreline position

352. Although Lake Erie does not experience an astronomical tide, lake
levels vary because of short- and long-term climatic changes. During the
5-year monitoring period, the highest recorded monthly mean level was 4.9 ft
above low water datum (LWD), and the lowest was 1.1 ft below LWD. (In 1986, a
new record high of 5.1 ft was established.) The greatest annual fluctuation
of monthly mean lake level was 2.75 ft, and a 1.5-ft surge was calculated to
have a recurrence interval of 1 year.

353. Suggestions of sinuous topographic development were noted during
the process of placing the fill, indicating a strong tendency for the beach to
adjust to the wave and current pattern produced by the breakwaters. In the
6-month interval between construction in October 1977 and May 1978, the shore-
line shape matured, and after approximately 1 year the planform was in an
equilibrium shape with a salient behind each detached breakwater. Aerial
photography shows well-formed salients during the lower lake levels in fall;
these become partially submerged and subdued during higher lake levels in

spring.

Wave climate

354. <A 3-year wave hindcast was performed by Saville (1953) for Cleve-
land, Ohio, located 28 miles east of the project site. With modifications for
differences in fetch and water depth, these data can be applied to Lorain.
The average wave height and period in the hindcast are 1.5 ft and 4.7 sec.
The maximum annual wave height is close to 8 ft, with periods up to 7 sec.
For calculation of shoreline change, waves are assumed to transport sand only

during an ice-free period from 1 April through 30 November.

Assembly of Data

355. Appendix D contains printouts of the input data files used in the
initial testing of the model and in final calibration and verification. The
OUTPT files are also given. Appendix D can be consulted for specifics associ-

ated with the discussion of the case study.

155

Data for the START file

356. The initial model configuration is contained in START_INIT. The
data in START_INIT represent the first modeling conceptualization of the site.
As discussed below, values for many quantities were taken from aerial photo-
graphs, whereas other data represent only an initial estimate. Values of
selected entries are now reviewed.

357. Line A.3. The lengths of the detached breakwaters are 250 ft and
the gaps between them 160 ft. Good resolution requires about 10 cells per
breakwater and about 4 cells in the gaps, leading to DX = 25 ft as a reason-
able value for describing detail of the breakwater configuration, yet not
giving an excessive number of calculation cells.

358. Line A.5. Because the wave data set was constructed with values
at 6-hr intervals, as will be discussed below, the time interval DT = 6 hr
is taken as a first guess. However, warnings of high values of the stability

parameter R, (STAB) are expected, since experience indicates that DX

s
= 25 ft is relatively small for use with a 6-hr time interval. The convenient
DT = 6 hr is tried to see how large the value of the stability parameter will
be under the wave conditions. If high values of R, occur, the value of DT
will be reduced until R, falls below 5 or few stability warnings occur.

359. Line A.12. The values of Kl and K2 will be determined in the
calibration process. As a first guess, nominal values are chosen. The value
of 0.77 is associated with the potential sand transport rate of about
21,500 cu yd/year. As the actual annual rate is much lower, the calibrated
value of Kl is expected to be smaller than 0.77.

360. Line B.1. The values of these change parameters may be altered at
a later stage, but, as a rule, they are initially set to give no change.

361. Line C.1. The native sand has a median grain size in the range of
about 0.15 to 0.20 mm. However, the median grain size of the fill material is
0.40 mm, so the latter value is used, since the fill predominates.

362. Line C.2. The design indicates the initial beach fill was placed
with a berm elevation of 8 ft.

363. Line C.3. The depth of closure is estimated to be twice the
maximum annual wave height, which for Lakeview Park is 8 ft according to

available wave data, giving a depth of closure of 16 ft.

156

364. Line D.1. Because the two groins are relatively short, they are
specified to be nondiffracting. (In the process of model calibration, the
groins can be easily changed to be diffracting to check model sensitivity to
this assumption. )

365. Lines D.4 and D.5. The configurations of the groins are read from
aerial photos and checked with construction plans.

366. Line F.2. Profile surveys made from October 1977 through November
1979 showed that the bottom slope was about 1:20 behind the detached break-
waters and 1:15 in the region of the gaps between the breakwaters. The chosen
slope, taken as an average for the whole area, is 1:18.

367. Line F.3. The east groin was built to be tight to prevent sand
from leaving the beach. It is assumed that permeability of the groins is low
and little sand transmission by overtopping occurs.

368. Lines F.4 and F.5. The amount of sand entering the project area
from the lateral boundaries is primarily controlled by the values assigned to
the lengths of the groins as measured from the shoreline position on the outer
side of the grid. Initial values of these lengths are taken from the aerial
photographs, but might change slightly during model calibration to achieve
optimal gating of sand across the boundary.

369. Lines G.6 and G.7. Geometrical properties defining the break-
waters are conveniently taken from aerial photographs.

370. Line G.9. The breakwaters are of standard layered rubble-mound
design (SPM 1984) and nongrouted; therefore, they are expected to be somewhat
permeable to incident waves. Also, during periods of high water levels and
high waves, wave transmission by overtopping will take place. The breakwaters
are expected to have relatively small values of transmission coefficients that
should be the same since the breakwaters were constructed of the same type of
stone and by the same procedure. However, the different water depths at the
breakwaters will change transmission properties, as will slight differences in
stone placement and structure settling. As an initial guess, the three
transmission coefficients are set to zero with the expectation that these
values will change.

371. Line I.1. Beach fills were placed before as well as after the

simulation interval, but not between the dates of the shoreline (aerial)

157

surveys selected for modeling. Therefore, a value indicating no beach fills

was given on this line.

Data for the SHORL files

372. There are several ways of obtaining shoreline positions, for
example, from closely spaced beach profile surveys, shoreline surveys,
stereoscopic photogrammetry, and controlled aerial photography. Numerous sets
of vertical aerial photographs were available to this study for which the
water level was known. From these photographs, the shoreline position was
digitized with respect to an arbitrary straight baseline drawn along the
revetment and parallel to the trend of the coast. The digitization was done
by hand because the longshore extent was short. Through a field investi-
gation, the average distance between the contour defining the water level and
a shoreline datum was determined for representative portions of the modeled
beach. These distances were then added to or subtracted from the distances
determined in the digitizing operation.

373. Aerial photographs were available for biannual flights flown
between 1 October 1977 and 18 September 1984. Among these, three were chosen
for use in this case study: 24 October 1977, 9 October 1978, and 17 November
UO) No beach fills were placed between October 1977 and 1980, making this
period uncomplicated and most suitable for simulations. The scale on the
available photographs was about 1:2,300 as determined from known lengths of
structures; these photographs were enlarged to a scale of 1:1,500 for hand
digitization, allowing shoreline position to be determined to the nearest
foot. An average error of 1 ft in shoreline position corresponds to a
volumetric error of 1,100 cu yd [(8+16)1,250/27].

374. Pope and Rowen (1983) reported average lake levels for the dates
of the selected aerial photographs to be 2.6, 2.4, and 2.5 ft, respectively.
The initial slope of the fill was 1:5, gradually approaching 1:12 during the
first 6 months after placement. By using an average foreshore slope of 1:12,
horizontal distances of 31.2, 28.8, and 30.0 ft, respectively, were added to
the digitized positions to estimate the true location of the shoreline. As
GENESIS cannot account for this transient profile adjustment, the transition
from the steeper to the gentler slope was assumed to have taken place at the

start of simulation on 24 October 19/77. This transition was schematized and

158

included in the shoreline location of 24 October. The profile was represented
by a straight line from the top of the berm at +8 ft to the depth of closure,
-16 ft. Further, the transition was assumed to rotate the profile around its
center, i.e., at -4 ft. Geometry then gives the setback associated with a
slope change from 1:5 to 1:12 to be 28 ft. This distance was subtracted from
the values representing the shoreline of 24 October 1977.

375. Walker, Clark, and Pope (1980) also report volumetric changes
within the project boundaries between the dates of the aerial photographs used
here. From October 1977 to October 1978, the project gained approximately
4,300 cu yd, whereas from October 1978 to November 1979 about 400 cu yd were
lost. Corresponding comparisons were made using the shoreline position files,
which indicated a gain of 13,500 cu yd from 1977 to 1978 and a loss of
6,900 cu yd from 1978 to 1979. Using the 1977 shoreline as a reference, these
volume changes convert to an average error of 8.4 ft (1 mm on the aerial
photographs) in determination of the 1978 shoreline and an error of 2.7 ft
(0.3 mm on aerial photographs) for the 1979 shoreline. To be consistent with
previous studies, the 1978 and 1979 shoreline positions were translated
forward 8.4 and 2.7 ft, respectively, resulting in volumetric differences of
4,260 cu yd from October 1977 to October 1978 and -335 cu yd from October 1978
to November 1979. The adjusted measured shoreline positions are shown in
Figure 40, and the corresponding SHORL files are given in Appendix D. As seen
from Figure 40, the general trend is for erosion along the western part of the
study area and accretion in the eastern part.

376. Figure 41 plots measured volumetric changes within the study area
using the October 1977 volume as a reference. The volumetric change varies
significantly with season, with a gain of sand over the winter and a loss
during the summer. Contrary to what might be expected, the seasonal varia-
tions appear to increase in time, rather than approaching an equilibrium. The
increase is probably explained by long-term variations in wave climate and
water level. Also, there are significant changes in beach volume from year to
year, although the general trend is accumulation for the fall and spring
measurements, with a least-squares determined value of 2,500 and

3,500 cu yd/year, respectively.

159

Shoreline position (ft)

—— Measured 10/24/77 Measured 10/09/78
—— Measured 11/17/79

0 200 400 600 800 1000 1200
Distance alongshore (ft)

Figure 40. Adjusted measured shoreline positions

Gain in 1000 cu yd
O

— Measured values ~—~Fall trend —— Spring trend

a
Oct Apr Oct Apr Oct Apr Oct Apr Oct Apr
77 | 78 | 79 | 80 | 81 ieee |

Date (month/year)

Figure 41. Measured volume changes within the study area

160

Data for the SEAWL file
377. The seawall in the model was placed at the location of the seawall
running along the beach, as read from the aerial photographs. The SEAWL file

is given in Appendix D.

Data for the DEPTH file

378. A DEPTH file was not required because an external wave transforma-
tion model was not used. The reasoning was that diffraction from the break-
waters was considered to be the dominant wave transformation process, and
alongshore variations in breaking wave height and direction because of wave
refraction over the relatively plane and parallel offshore bathymetry would be

comparatively small.

Data for the WAVES file

379. As in most shoreline change modeling studies, wave measurements
for the site for the time interval between measured shoreline positions were
not available. Instead, a well-known 3-year wave hindcast for Lake Erie for
the period 1948-1950 was used (Saville 1953) and checked for general trends
with readily available gage data. The hindcast, presented in tabular form,
was originally developed for Cleveland, Ohio, located 28 miles east of Lorain.
Also, a more recent wave data time series of height and period was available
from a gage located in 30 ft of water off Cleveland Harbor for the period
September to November 1981. The gage data were used to modify the time series
developed from the hindcast in three stages, as discussed below.

380. Breaking waves are the principal driving force for longshore sand
transport. Therefore, an effort must be made to prepare a wave data set with
properties that produce reasonable transport rates. For this case study, the
GDM (USAED, Buffalo 1975) provided the basic information about the general
sediment transport condition in the area. Key findings used for guidance in
preparing the wave data set were:

a. Far from the influence of wave sheltering by Lorain Harbor,
the net transport in the area is estimated to be from east to
west with an annual rate of about 60,000 cu yd.

Because of sheltering of waves from the west by Lorain Harbor,
the net transport at Lakeview Park is from west to east with
an estimated net potential rate of 21,500 cu yd per year. The
estimated annual gross potential rate is about 164,000 cu yd.

161

c. Because of a limited supply of sand, the potential transport
rates are not realized. The actual net transport rate is
estimated to be in the range of 5,000 to 8,000 cu yd/year.

d. Significant sand transport can occur only during the ice-free

period from April through November. During the remainder of
the year, the wave height should be considered as being
effectively zero for the purpose of shoreline change modeling.

381. The first step was to produce a time series of offshore wave
period, height, and direction data using tables presented in Saville (1953).
For the ice-free period, the hindcast wave climate was defined as "calm" for
as much as 73 percent of the time. However, the modelers believed that some
wave activity must occur during at least a portion of the hindcast calm
periods. As a compromise, in development of the wave time series for this
case study, a "calm" deepwater wave condition was initially defined as
T=2 sec, H=1 ft, and 6 =0 deg. Sample lines from the initially
prepared file WAVES_INIT are listed in Table 4, in which lines of WAVES files

modified as will be discussed below are given for comparison.

Table 4

Sample Entries Illustrating Development of the WAVES File

WAVES - INIT WAVES -2T WAVES - CNG WAVES - DIFF
rT H 6 at H 6 T H 6 rT H 0
SCC ye Lceuces. SCC pet amcer: SOC Te caer Seca) pEtauaden:
4A5e05s00" 353 SOMES OO 53) SHOMG OOM 253 8108 306 Wwa38
3.0) 200 S80 6024008 30 60,1 12)-40m = 30 640) havo mes0
3501 2,000 =8 FA) DOO): eas GOn 12020 8 JO malas =f
230 HL 00 ) 490 11500 0 4010 sale O0Me- 10 450) JONS6 aeAlO
Sy.) Pn) 9 505 60m 2500 als BE) Oe als 3.0 sys 1S
370) 12001) 938 620 1 22008 1238 600 E60)" 38 630) 160.08
4.0 3.00 60 SiO) 4311001760 SOM 240 en 160 8.0 2.40 60

382. From the time series developed for the WAVES.INIT data file, wave
climates for September, October, and November were extracted and compared with
the measured time series from 1981. Table 5 shows a comparison between wave

properties measured in 1981 and those based on the hindcast of Saville (1953).

162

Table 5
Comparison Between Measured and Hindcast Waves

Measured Hindcast Comparison Hindcast Comparison
Waves Sep - Nov Sep - Nov Apr _- Nov Apr _- Nov
H Lt Hy Th Hh Th
Month ft sec ft sec H/H,, T,/Th fit sec H/H, T,/Th
Sep D2 47 ahs) 2.4 0.8 19 -- -- -- --
Oct oO) fa’) A Qa eh rere -- -- -- --
Nov IU) aU ea 25 0.9 158) -- -- -- --
AVG Wel hay ES, 2.4 1.0 2.0 155) 2.4 1.0 1be8)

Note: H = measured significant wave height; Tp = measured peak wave period;
H, = hindcast significant wave height; T, = hindcast significant wave period.

383. As seen from Table 5, there was good agreement between wave
heights for the two data sets, whereas the period for the measured waves is
about twice that of the hindcast. Assuming that the measurements are repre-
sentative, the hindcast was modified by multiplying the periods by a factor of
2, with the constraint that the wave period could not be greater than 8 sec.
The result of this transformation to a new wave data file called WAVES _2T is
illustrated by sample lines in Table 4.

384. The GDM (USAED, Buffalo 1975; Walker, Clark, and Pope 1980; Pope
and Rowen 1983) derived estimates of the longshore sand transport rates
described above using an equation similar to Equation 2 with Kl =0./77 and
K2 = 0.0 . Therefore, to be compatible with the original estimates made by
specialists who knew the coast, the same values were used to calculate annual
potential transport rates for a straight shoreline without structures. The
calculated rates should correspond to the previously reported potential rates.
Table 6 shows selected calculated transport rates obtained using the modified
WAVES file.

385. As shown in Table 6, with a positive transport rate defined from

west to east, the calculated annual net transport rate was of the correct

163

Table 6
Calculated Annual Potential Transport Rates

Angle to
Wave Shoreline No. of Net Rate Gross Rate

Direction deg Events 10° cu yd/year 10° cu yd/year
NNE -53 55 -41 --

N -30 49 -26 --

NNW -8 47 -18 --

CALM 0 713 0 --

NW 15 37 23 --

WNW 38 49 76 --

W 60 26 38 --

All Directions 976 51 224

order of magnitude, but in the wrong direction. No information was available
for comparing the calculated gross transport rate. Several factors in the
derivation of the wave time series might account for the difference between
the present and previously calculated net annual transport rates: the
simplified method of hindcasting the waves in producing the wave tables; the
somewhat arbitrary development of the time series from the hindcast statis-
tics; and the assumption that the 3-year period 1948-50 is fully represen-
tative for the situation after 1977. But the major reason for the difference
is probably that the wave data set pertains to Cleveland and does not account
for local characteristics at Lorain. In particular, as the fetch for westerly
waves is shorter for Lorain, waves from the west are expected to be smaller at
Lorain than at Cleveland.

386. Taking all these factors into account, the wave height in the time
series was modified by multiplying by the following values (representing
educated guesses to produce the desired effect) according to direction to
develop a new wave time series: 0.8 (W), 0.8 (WNW), 0.9 (NW), 1.0 (calm),

1.1 (NNW), 1.2 (N), and 1.2 (NNE). Also, during periods of the modified calm
conditions as described above, the offshore wave direction was set to -10 deg
to the trend of the shoreline rather than perpendicular to better represent
the longer fetch to the northeast. The transformation to the new wave data

file WAVES_CNG is illustrated by sample lines in Table 4. Using the new wave

164

time series, the annual net transport rate was calculated to be -57,000 cu yd,
and the gross rate was calculated to be 227,000 cu yd. Thus, agreement with
the net rate of -60,000 cu yd as given in the GDM (USAED, Buffalo 1975) is now
very good.

387. The next step in preparation of the WAVES input file was to
include the shadowing or diffraction effect of Lorain Harbor. However,
because of the limited size of the Lakeview Park project and the considerable
distance between it and the lakeward ends of the harbor structures, it was not
possible to include the effect of the harbor directly in simulations by
GENESIS. Instead, a computer routine was written to recalculate a new
offshore wave time series, including the influence of the harbor. At each
6-hr interval in the wave time series, the routine read the triplet (T, Hj,
8,) at the 30-ft contour, transformed the wave conditions to the depth of the
outer breakwater tip (28 ft), and calculated a representative diffraction
coefficient K,) for the Lakeview Park region following the procedure
described by Kraus (1984, 1988a). A modified offshore wave height was then
calculated as H'’ = K) H, . Also, the wave angle was restricted to be greater
than -33 deg, representing the line between the outer breakwater tip and
Lakeview Park. The resultant modified wave heights by direction are summar-
ized in Table 7.

388. The transformation to the modified wave data file WAVES_DIFF is
illustrated with sample lines in Table 4. Using this new time series to
represent wave conditions at Lakeview Park, the annual net transport rate was
calculated to be 22,000 cu yd, and the gross rate was calculated to be
144,000 cu yd. Thus, agreement with the previously obtained net rate of
21,500 cu yd and the gross rate of 164,000 cu yd is good.

389. In summary, through use of third-party coastal experience at the
site together with modeling judgment, the original file WAVES_INIT was
modified in a series of steps to arrive at WAVES_DIFF, which was developed to
have desirable properties for serving for calibration and verification of
GENESIS. Being satisfied with premodeling testing of the wave time series,
WAVES_DIFF was copied over to serve as the input wave file WAVES.DAT (Appendix
D) to drive GENESIS.

Table 7

Modified Average Wave Height Because of
Shadowing by Lorain Harbor

Original Modified
Wave H, H'
Direction fit ft H'/H,
NNE 259. 1.24 0.49
N 2.41 1.78 0.74
NNW 2.64 Se 0.90
CALM 1.00 0.90 0.90
NW 3403 2.92 0.97
WNW 3.3 3.27 0.99
W 327 3.26 0.99
All 1.49 GZ) 0.87

Calibration and Verification

390. The calibration and verification process in a design situation
requires a large number of simulations. Values of the calibration parameters
Kl and K2 are varied to obtain agreement between measured and calculated
shoreline change over a known time interval as well as to produce realistic
estimates of longshore sand transport rates. Initial estimates of some other
parameters may also need to be altered.

391. In the course of calibration for Lakeview Park, usually only one
parameter at a time was changed in order to isolate its effect and understand
its role in the overall balance with other parameters. The strategy was to
first determine values of main parameters controlling known quantities, in
this case the net transport rate and volumetric change inside the study area.
These parameter values were determined at the first stage of calibration, and
parameters having mainly local and more minor influence were then used to
optimize the calibration at the final stage.

392. For the present case, the value of the primary calibration
parameter Kl was varied first until calculated overall net transport rates

were close to the previously determined values. Second, the parameter K2

166

was varied alternately with the distance YGl to obtain the approximate
magnitude of net inflow of sand from the west. Third, the transmission coef -
ficients of the breakwaters were adjusted to obtain the correct size of the
salients behind the detached breakwaters. Fourth, the longshore location of
the eastern detached breakwater was translated two grid cells to the east to
obtain better agreement between calculated and measured positions of the
easternmost salient. This small adjustment can be thought of as compensating
for the finite grid size and oversimplification of the detached breakwaters as
thin. Finally, the modelers "stepped back" from the calibration procedure and
examined the results to see if there was a reasonable balance among the
parameters and overall replication of the shoreline change and historic
transport rates. The calibration result is shown in Figure 42, and the
corresponding START and OUTPT files are given in Appendix D.

393. Figure 42 shows good agreement between the measured and calculated
shoreline positions. The calculated CVE indicated that the mean absolute
difference between the two shoreline positions was 4 ft. The calculated
volumetric change was 4,400 cu yd compared with the measured 4,300 cu yd,
again, a very good result.

394. If data are available, model predictions should be verified by
reproducing measured shoreline change over a time interval independent of the
calibration interval. Sensitivity testing should also be done with the
calibrated model, with emphasis placed on sensitivity testing if verification
data are not available. In the present case, shoreline position data were
available for verification, but wave data over the interval between shoreline
surveys were not. (Additional gage data are available for Lakeview Park and
Cleveland which could be used to develop a more extensive wave data base,
including examination of variability. Development of an expanded wave data
set was beyond the scope of this illustrative case study, however. )

395. Verification was made for the 13-month interval between 9 October
1978 and 17 November 1979. As stated, only 1 year of wave data was available.
It is doubtful that the same wave conditions that resulted in a net gain of
4,300 cu yd during the calibration period would likely produce a net loss of
300 cu yd for the verification period if all other conditions were left

unchanged (although the shoreline shape and position did change).

167

Shoreline position (ft)

— Measured 10/24/77
— Calculated 10/09/78

Measured 10/09/78

WZZZLZLZLZZZLZLZZ7I

200 400 600 800 ‘1000 1200
Distance alongshore (ft)

Figure 42. Result of model calibration

396. Aerial photographs indicated that the shoreline in the small
pocket beach on the east side of the east groin had receded, almost doubling
the distance from the shoreline to the seaward end of the groin between 1978
and 1979. Therefore, for the verification, YGl was increased from 70 ft
used in the calibration to 128 ft for the verification, as read from the
photographs.

397. The model was then run for the verification period by using the
l-year wave field, and reasonable agreement was obtained between calculated
and measured shoreline position. Subsequent sensitivity testing indicated
that better results could be obtained if the wave height were increased by on
the order of 10 percent. Therefore, the value HCNGF = 1.1 was entered on
line B.1 in the START file. Other than changing YGl and HCNGF , all other
input values were the same as for the calibration. The verification result is
shown in Figure 43. Similar to the case of the calibration, the measured and

calculated shoreline positions for the verification are in good agreement.

168

Shoreline position (ft)

— Measured 10/09/78 Measured 11/17/79
— Calculated 11/17/79

T
200 400 600 800 1000 1200
Distance alongshore (ft)

Figure 43. Result of model verification

The mean absolute difference between the two shorelines was 4 ft; calculated

volumetric change was -311 cu yd compared with the measured -335 cu yd.

Sensitivity and Variability Tests

398. Prior to using a verified model for predicting shoreline change
for alternative designs, the sensitivity of the calculated shoreline response
to variations in different key input parameters in the START file should be
examined in a systematic manner. (The identification of "key" input para-
meters will depend, in part, on the expected applications. ) Although here
only an analysis is made for selected parameters, the user is advised to

undertake similar analyses with several parameters to gain understanding

169

between the change in the input (cause) and resultant change in the output

(effect) for the specific project.

Kl, K2, and median grain size
399. Figure 44 shows the results of sensitivity tests examining changes

in the calibration parameters Kl and K2 and median grain size D50 . An
increase in Kl from 0.42 to 0.52 resulted in a slight increase in sand
volume inside the study area, but the shape of the shoreline was almost
identical to that in the verification. An increase in K2 from 0.12 to 0.22
produced more pronounced salients, as expected, but slightly more sand was
lost from the system than for the verification simulation. Both cases show
that the simulated change was only moderately sensitive to reasonable changes
in the calibration coefficients.

400. Almost all of the material lost was removed from the beach section
adjacent to the western groin. The probable explanation for the localized
loss of sand is the bias for the transport to be from west to east because of
wave shadowing by Lorain Harbor; in other words, this is simply a downdrift-
groin erosion phenomenon.

401. It is known that fill with a median diameter smaller than that of
the native material requires larger initial quantities to create the same
stable beach as a fill of larger diameter. However, the present structure
configuration is very efficient in preventing the beach from eroding. The
calculation using a median sand grain size 0.2 mm, half the diameter used in
the actual project, shows very pronounced salients behind two of the break-
waters and gives a net increase of sand of about 780 cu yd as compared with
the net loss of 340 cu yd by using the actual grain size 0.4 mm. The finer
grain size produces a gentler equilibrium profile and places the breaker line
farther offshore. However, the structures were not moved offshore to their
depth of placement by changing the START file, making this example somewhat
unrealistic.

402. It is important to note again that GENESIS does not take losses to
the offshore into account, which are expected to be greater for finer
material, and the model is expected to overestimate the performance of the

finer fill material.

170

Shoreline position (ft)

700
—— Verification Tans Slopfey2 TS i OSI oe UG CRe D50 = 0.2
6007
ZZZZZZZZZZZ ZZ
50074 WZZZLZZZZZZLZ ZZ
400

800

200

O 200 400 600 800 1000 1200
Distance alongshore (ft)

Figure 44. Model sensitivity to changes in Kl , K2 , and D50

Wave transmission and offshore waves

403. Figure 45 illustrates model sensitivity to changes in the trans-
mission of the breakwaters and to the offshore wave height and direction. The
solid line represents a case where all three transmission coefficients were
decreased by 0.2 resulting in K, of 0.3, 0.02, and 0.1 as compared with the
original values of 0.5, 0.22, and 0.3, respectively, from the west to east
breakwater. The breakwaters were constructed at the same time and have the
same cross sections. Therefore, the transmission coefficients should be
equal. Simulations with a single value of K, close to the average of those
above also gave good results, but the calculated beach planform could be made
to closely reproduce the measured planform by using unequal values. From the
pragmatic perspective of obtaining the best calibration, differences in K,
values over the determined range were considered acceptable.

404. With the exception of the western part of the beach, smaller

transmission coefficients result in larger salients without a corresponding

Shoreline position (ft)

— Verlficatlon —— Decreased transm,

S>) InIGINIGHE She

O 200 400 600 800 1000 1200
Distance alongshore (ft)

Figure 45. Model sensitivity to changes in Ky, , HCNGF , and ZCNGA

increased recession of the shoreline behind the gaps between structures. As a
whole, the decreased wave transmission simulation produced net accumulation in
the area.

405. An increase in wave height of about 10 percent, produced by
changing HCNGF from 1.1 used in the verification to 1.2, had almost the same
effect as an increase of Kl , i.e., a slight increase in volume contained by
the project, but the calculated shoreline position shows very little departure
from the verification result. Setting ZCNGA = -10 means that the offshore
wave direction was uniformly shifted 10 deg to the east. The calculated
result confirms the intuitive picture that erosion should decrease on the
western side of the project and increase on the eastern side. Again, the
calculated results indicate a moderate or low sensitivity of the model to

changes in the input parameters.

Alternative Structure Configurations

406. After the modeling system had been calibrated, verified, and
tested, it was possible to study alternative strategies for maintaining the
beach fill in place. Walker, Clark, and Pope (1980) also discuss alternatives
considered in arriving at the final choice of using detached breakwaters.
Obvious alternatives are to remove the (expensive) detached breakwaters and/or
groins in order to assess quantitatively the necessity for keeping them in
place. This type of information might be useful if another project is to be
constructed on a similar coast. An important limitation in this analysis is
the absence of the probable mitigating effect of the breakwaters on offshore
transport, which is not accounted for in GENESIS.

407. Shoreline change over the verification period 9 October 1978 to

17 November 1979 for three alternative configurations was investigated:

Existing groins without detached breakwaters.

Existing breakwaters without the terminal groins.

c. Extended groins without detached breakwaters.
For case c, by trial and error the groins were extended to the length required
to give the same volume change for the site as the existing (design) condition
of detached breakwaters and shorter groins. Results of the simulations are
shown in Figure 46. For the case with only the groins of existing length, the
salients are absent, as was expected. More serious is the significant loss of
57,000 cu yd of fill, about half of the initial fill of 110,000 cu yd.

408. To simulate the case of removing the two groins, 20 cells were
added on each side of the original calculation grid. The added shoreline/sea-
wall positions were read from aerial photographs except for the farthest few
cells, which were not covered by the photographs and were extrapolated by
hand. Thus, the model contained 89 cells for this particular simulation.

The value of NN on Line A.3 in the START file was set to 89, and the grid
cell numbers of the detached breakwaters on Line G.6 were incremented by 20.
As seen from Figure 46, the beach fill did very well on the updrift (west)
side. In fact, slight accretion may be observed here since the west groin had
been removed. Evidently this groin not only prevents sand from leaving the

enclosed beach, but also prevents it from entering.

Shoreline position (ft)

— Grolns+breakwaters wz —— Only groins ZZZ)
—- Only breakwaters ZZ “Only extended groins masy
ZLZZZ22Z7ZZ LZ ZAI

WZZZZZLZZZLZLZZ29

200 400 600 800 1000 1200
Distance alongshore (ft)

Figure 46. Shoreline change for alternative configurations

409. On the downdrift (east) end of the fill, the simulation indicated
that the groin there is essential for retaining the beach. After removing the
east groin, the shoreline receded about 210 ft at the eastern project bound-
ary. At the same time, the whole area lost 50,000 cu yd, only slightly less
than the amount lost in the alternative without breakwaters.

410. As the third hypothetical alternative, a simulation was made to
investigate the length of the two terminal groins required to hold the beach
in place to the same extent as the existing condition of combined groins and
breakwaters. (Again, it is emphasized that cross-shore transport is not
accounted for in this comparison; a tendency for fill to be transported
offshore is considered to be a significant factor in the Great Lakes.) As
indicated in Figure 46, the western groin had to be extended by 210 ft and the
eastern groin by 320 ft to produce a net loss of sand of 285 cu yd (50 cu yd
less than in the existing condition). Thus, according to the calculations and
omitting consideration of cross-shore transport, it would be possible to build
another 530 ft of groins rather than 750 ft of detached breakwaters to hold
the beach fill in place. Since construction of groins is naturally shore-

based, the groins are located in shallower water than the breakwaters over a

174

major portion of the structures, and less stone would be required, the groin
extension alternative would be less expensive to build than the detached
breakwater alternative. However, in the extended groin case, it is probable
that offshore losses produced by steep waves and rip currents tending to form
at groins would make the relative performance of the groins much inferior to
detached breakwaters for containing the beach. The long groin alternative was
rejected by the Corps of Engineers (USAED, Buffalo 1975) because of potential
impacts on adjacent shores.

411. In conclusion, the simulations confirm that the combination of
detached breakwaters and terminal groins is superior to simpler designs in
holding the beach fill in place. Both the groin-only design and segmented
detached breakwater-only design perform poorly, causing about half of the fill

to be lost in 1 year, which is unacceptable.

Five-Year Simulation

412. It is interesting to perform a 5-year simulation with the cali-
brated model since shoreline position data are available for this period.
Normally, such a long-term projection would be one of the objectives of a
design study, whereas in the present case the simulation provides further
verification of the model. In this illustrative case study, only a 1l-year-
long wave data file is available, precluding estimation of a likely range of
predicted shoreline positions resulting from possible variations in the wave
climate. Also, the time dependence of YG1l , associated with the pocket beach
to the west of the project, is unknown. The calibrated model was used with
the distance YGl = 90 ft to give the average annual fall trend of a net gain
of 2,500 cu yd.

413. Figure 47 plots calculated annual net volume for the 5-year
simulation extending from 24 October 1977 to 14 December 1982. The average
net annual gain in volume was 2,400 cu yd, close to the trend in fall measure-
ments of 2,500 cu yd. The measurements show a net gain of 3,300 cu yd for the
second year, reduction to 2,500 cu yd in the third and fourth years, and a

further reduction to 2,000 cu yd in the fifth year. The measurements show

LZ/S)

consistent small gains in material that appear to be decreasing as the project
slowly approaches a dynamic equilibrium.

414. Figure 48 is a plot of the calculated and measured shoreline in
positions in December 1982. The calculation was begun in October 1977, and
the l-year wave data set was repeated. GENESIS predicted major shoreline
change from 1977 through 1980 and only slight change thereafter, indicating
that the project had adjusted to equilibrium with the l-year data set.

415. Calculated and measured 1982 shorelines are in almost perfect
agreement along the eastern two-thirds of the project, with the model repro-
ducing the locations and shapes of the salients. It is also interesting to
note that the model predicts the small shoreline recession observed within the
distance of about 300 ft from the east groin. Erosion in the vicinity of the
west groin is qualitatively reproduced, but the magnitude is less than the
measured amount. Three reasons can be given for the underestimation:

Inadequate wave time series.

b. Wave diffraction by the groin, which was omitted in the model.

c. Local effects, such as a rip current.
It is believed that the three reasons are important in the order they are
given. In particular, the opening between the tip of the west groin and the
western-most breakwater is relatively great, making the exposed area in that
energy window more sensitive to variations in the wave climate than the
protected areas in the shadow zone of the breakwaters. Additional sensitivity
testing would easily shed light on whether the model prediction could be
improved in the vicinity of the west groin without degrading the prediction

elsewhere; this task is left as an exercise for the reader.

Summary and Discussion

416. The presented case study provides an example of data preparation,
interpretation of previously obtained results, calibration and verification
procedures, and, finally, use of the model to analyze alternative project
designs. A description of many of the intermediate simulations had to be
omitted, and it is emphasized that the treatment is somewhat schematic as

compared with actual design applications.

176

Gain in 1000 cu yd

—— Measured values —- Fall trend — Calculated values

@ct Apr Oct Apr + Oct! Apri Oct Nope) @©ctes Aor » ct
77 | 78 | 79 | 80 | 81 lim wee?

Date (month/year)

Figure 47. Volume change, October 1977-December 1982

Shoreline Position (ft)

Measured 10/24/77 —— Calculated 10/24/80
— Calculated 12/14/82 —— Measured 12/14/82

WZZLZLZLLZZZZZ 2A

O 200 400 600 800 1000 1200
Distance Alongshore (ft)

Figure 48. Shoreline change, October 1977-December 1982

177

417. It is recognized that every new application adds a new challenge
to the art of shoreline simulation and that it is not possible to follow
completely a set pattern or operating procedure. At the same time, however,
modeling experience produces growth in this highly complex and integrated
process, with each new application better preparing the modeler for the next.
Therefore, the case study was presented with the dedication that it will point
newcomers in the proper direction to analyze correctly other coastal protec-
tion problems.

418. The case study demonstrates that the modeling system GENESIS is
highly effective for simulating the influence of waves and coastal structures
on the long-term evolution of sandy beaches and that the system is capable of
serving as an engineering tool for evaluating shore protection projects. The
case study also emphasizes the importance of analyzing and understanding the
input data and coastal processes in the region and at the project. Among the
various factors entering a modeling project, all possible ingenuity and
industry must be applied to develop correct input wave time series and
boundary conditions. A lesson learned from the case study is the fragility of

the modeling system to errors in the input data.

178

REFERENCES

Bakker, W. T. 1968. "The Dynamics of a Coast with a Groyne System," Proceed-

ings of the 11th Coastal Engineering Conference, American Society of Civil
Engineers, pp 492-517.

Bruun, P. 1954. "Coast Erosion and the Development of Beach Profiles,"
Technical Memorandum No. 44, Beach Erosion Board, US Army Corps of Engineers,
Waterways Experiment Station, Vicksburg, MS.

Ghuteyn. Gravens, M. Bi Smith, J Ms. (Gorman, Le. Le. and) Chen; H. 'S%) 1987.
"Beach Erosion Control Study, Homer Spit, Alaska," Miscellaneous Paper CERC-
87-15, US Army Engineer Waterways Experiment Station, Coastal Engineering
Research Center, Vicksburg, MS.

Crank, J. 1975. The Mathematics of Diffusion, 2nd ed., Clarendon Press,
Oxford, England.

Dally, W. R., and Pope, J. 1986. "Detached Breakwaters for Shore Protec-
tion," Technical Report CERC-86-1, US Army Engineer Waterways Experiment
Station, Coastal Engineering Research Center, Vicksburg, MS.

Dean, R. G. 1977. “Equilibrium Beach Profiles: US Atlantic and Gulf
Coasts," Ocean Engineering Report No. 12, Department of Civil Engineering,
University of Delaware, Newark, DE.

Ebersole, B. A. 1985. "Refraction-Diffraction Model for Linear Water Waves,"

Journal of Waterway, Port, Coastal, and Ocean Engineering, Vol 111, No. WW6,
Pp 939-953).

Ebersole, B. A., Cialone, M. A., and Prater, M. D. 1986. "RCPWAVE - A Linear
Wave Propagation Model for Engineering Use," Technical Report CERC-86-4, US
Army Engineer Waterways Experiment Station, Coastal Engineering Research
Center, Vicksburg, MS.

Goda, Y. 1984. Random Seas and Design of Maritime Structures, University of
Tokyo Press, Tokyo, Japan.

Goda, Y., Takayama, T., and Suzuki, Y. 1978. "Diffraction Diagrams for

Directional Random Waves," Proceeding of 16th Coastal Engineering Conference,
American Society of Civil Engineers, pp 628-650.

Gravens, M. B. 1988. "Use of Hindcast Wave Data for Estimates of Longshore

Sediment Transport," Proceedings Symposium on Coastal Water Resources,
American Water Resources Association, pp 63-72.

Gravens, M. B. "Comprehensive Shoreline Response Computer Simulation,
Report 2: Bolsa Bay, California, Proposed Ocean Entrance System Study,"
Miscellaneous Paper in preparation, US Army Engineer Waterways Experiment
Station, Coastal Engineering Research Center, Vicksburg, MS.

179

Gravens, M. B., and Kraus, N. C. 1989. "Representation of the Groin Boundary
Condition in Numerical Shoreline Change Models," Proceedings XXIII Congress,
International Association of Hydraulic Research, pp C515-C522.

Gravens, M. B., Scheffner, N. W., and Hubertz, J. M. 1989. "Coastal
Processes from Asbury Park to Manasquan, New Jersey," Miscellaneous Paper
CERC-89-11, US Army Engineer Waterways Experiment Station, Coastal Engineering
Research Center, Vicksburg, MS.

Hallermeier, R. J. 1983. "Sand Transport Limits in Coastal Structure

Design," Proceedings of Coastal Structures '83, American Society of Civil
Engineers, pp 703-716.

Hanson, H. 1987. "GENESIS, A Generalized Shoreline Change Model for
Engineering Use," Report No. 1007, Department of Water Resources Engineering,
University of Lund, Lund, Sweden.

1989. "GENESIS - A Generalized Shoreline Change Numerical
Model," Journal of Coastal Research, Vol 5, No. 1, pp 1-27.

Hanson, H., and Kraus, N. C. 1980. "Numerical Model for Studying Shoreline
Change in the Vicinity of Coastal Structures," Report No. 3040, Department of
Water Resources Engineering, University of Lund, Lund, Sweden.

1985. "Seawall Constraint in the Shoreline Numerical Model,"

Journal of Waterway, Port, Coastal _ and Ocean Engineering, Vol 111, No. 6,
pp 1079-1083.

1986a. "Forecast of Shoreline Change Behind Multiple Coastal
Structures," Coastal Engineering in Japan, Vol 29, pp 195-213.

1986b. "Seawall Boundary Condition in Numerical Models of
Shoreline Evolution," Technical Report CERC-86-3, US Army Engineer Waterways
Experiment Station, Coastal Engineering Research Center, Vicksburg, MS.

Hanson, H., and Larson, M. 1987. "Comparison of Analytic and Numerical
Solutions of the One-Line Model of Shoreline Change," Proceedings of Coastal
Sediments '87, American Society of Civil Engineers, pp 500-514.

Hanson, H., Kraus, N. C., Nakashima, L. D. 1989. "Shoreline Change Behind
Transmissive Detached Breakwaters," Proceedings Coastal Zone '89, American
Society of Civil Engineers, pp 568-582.

Horikawa, K., and Hattori, M. 1987. "The Nearshore Environment Research

Center Project," Proceedings Coastal Sediments ‘87, American Society of Civil
Engineers, pp /56-/71.

Hunt, J. F. 1979. "Direct Solution of the Wave Dispersion Equation," Journal

of Waterway, Port, Coastal, and Ocean Engineering, Vol 105, No. WwW4,
pp 457-459.

180

Jensen, R. E. 1983a. "Methodology for the Calculation of a Shallow-Water
Wave Climate," Wave Information Study Report No. 8, US Army Engineer Waterways
Experiment Station, Coastal Engineering Research Center, Vicksburg, MS.

. 1983b. "Atlantic Coast Hindcast, Shallow-Water Significant Wave
Information," Wave Information Study Report No. 9, US Army Engineer Waterways
Experiment Station, Coastal Engineering Research Center, Vicksburg, MS.

Jensen, R. E., Hubertz, J. M., and Payne, J. B. 1989. "Pacific Coast
Hindcast Phase III North Wave Information," Wave Information Study Report No.
17, US Army Engineer Waterways Experiment Station, Coastal Engineering
Research Center, Vicksburg, MS.

Komar, P. D. 1988. "Environmental Controls on Littoral Sand Transport,"

Proceedings of 21st Coastal Engineering Conference, American Society of Civil
Engineers, pp 1238-1252.

Komar, P. D., and Inman, D. L. 1970. “Longshore Sand Transport on Beaches,"
Journal of Geophysical Research, Vol 73, No. 30, pp 5914-5927.

Kraus, N. C. 1981. "One-Line Development and Simulation for Oarai Beach,"
NERC Report No. 13, Cooperative Research of Surf Zone Dynamics, Part 3,
Beaches Near Breakwaters and Rocky Coasts, Nearshore Environment Research
Center, Tokyo, Japan, pp 155-192.

1982. "Pragmatic Calculation of the Breaking Wave Height and

Wave Angle Behind Structures," Proceedings of 29th Japanese Coastal Engineer -
ing Conference, Japan Society of Civil Engineers, pp 295-299. (in Japanese)

1983. "Applications of a Shoreline Prediction Model," Proceed-

ings of Coastal Structures '83, American Society of Civil Engineers, pp 632-
645.

1984. "Estimate of Breaking Wave Height Behind Structures,"

Journal of of Waterway, Port, Coastal and Ocean Engineering, Vol 110, No. 2,
pp 276-282.

. 1988a. "Part IV: Prediction Models of Shoreline Change,"
Chapter 2, Wave Model, In: kK. Horikawa, Ed., Nearshore Dynamics and Coastal

Processes: Theory, Measurement, and Predictive Models, University of Tokyo
Press, Tokyo, Japan, pp 324-328.

1988b. "Part IV: Prediction Models of Shoreline Change,"
Chapter 3, Shoreline Change Model, In: K. Horikawa, Ed., Nearshore Dynamics

and Coastal Processes: Theory, Measurement, and Predictive Models, University
of Tokyo Press, Tokyo, Japan, pp 329-336.

1988c. "Part IV: Prediction Models of Shoreline Change,"
Chapter 4, Numerical Calculation Method, In: kK. Horikawa, Ed., Nearshore

Dynamics and Coastal Processes: Theory, Measurement, and Predictive Models,

University of Tokyo Press, Tokyo, Japan, pp 337-344.

181

Kraus, N. C. 1988d. "Part IV: Prediction Models of Shoreline Change,"
Chapter 6, Case Studies of Application of the Shoreline Change Model,

In: K. Horikawa, Ed., Nearshore Dynamics and Coastal Processes: Theory,
Measurement, and Predictive Models, University of Tokyo Press, Tokyo, Japan,
pp 355-366.

1989. "Beach Change Modeling and the Coastal Planning Process,"
Proceedings Coastal Zone ‘89, American Society of Civil Engineers, pp 553-567.

Kraus, N. C., and Dean, J. L. 1987. “Longshore Sediment Transport Rate
Distribution Measured by Trap," Proceedings of Coastal Sediments '87, American
Society of Civil Engineers, pp 881-896.

Kraus, N. C., Gingerich, K. J., and Rosati, J. D. 1988. "Toward an Improved
Empirical Formula for Longshore Sand Transport," Proceedings of 21st Coastal
Engineering Conference, American Society of Civil Engineers, pp 1182-1196.

Kraus, N. C., Hanson, H., and Harikai, S. 1984. "Shoreline Change at Oarai
Beach, Japan: Past, Present and Future," Proceedings of 19th Coastal
Engineering Conference, American Society of Civil Engineers, pp 2107-2123.

Kraus, N. C., Hanson, H., and Larson, M. 1988. "Threshold for Longshore Sand
Transport and Application to a Shoreline Change Simulation Model," Proceedings

on Mathematical Modelling of Sediment Transport in the Coastal Zone, Inter-
national Association of Hydraulic Research, pp 117-126.

Kraus, N. C., and Harikai, S. 1983. "Numerical Model of the Shoreline Change
at Oarai Beach," Coastal Engineering, Vol 7, No. 1, pp 1-28.

Kraus, oN. G.,) Harika), S2; and Kubota. Sk VSS (4Ay Numerical ModellMotuathe
Breaking Waves and Long-Term Shoreline Change at Oarai Beach," Proceedings of

28th Japanese Coastal Engineering Conference, Japan Society of Civil
Engineers, pp 295-299. (in Japanese)

Kraus, N.C., Isobe, M., Igarashi, H., Sasaki, T., and Horikawa, K. 1982.
"Field Experiments on Longshore Sand Transport in the Surf Zone," Proceedings

of 18th Coastal Engineering Conference, American Society of Civil Engineers,
pp 969-988.

Kraus, N. C., and Larson, M. 1988. "Prediction of Initial Profile Adjustment
of Nourished Beaches to Wave Action," Proceedings Annual Conference on Shore
and Beach Preservation Technology, Florida Shore and Beach Preservation
Association, pp 125-137.

Kraus, N. G., Scheffiner, N. WW.) Chou; Le We) iCiallones)M. “Aq. Smithy Ji Mereand
Hardy, T. A. 1988. "Coastal Processes at Sea Bright to Ocean Township, New
Jersey," Vol 1: Main Text and Appendix A, Miscellaneous Paper CERC-88-12, US
Army Engineer Waterways Experiment Station, Coastal Engineering Research
Center, Vicksburg, MS.

Kriebel, D. 1982. "Beach and Dune Response to Hurricanes," M.S. Thesis,
Department of Civil Engineering, University of Delaware, Newark, DE.

182

Kriebel, D., and Dean, R. G. 1985. "Numerical Simulation of Time-Dependent
Beach and Dune Erosion," Coastal Engineering, Vol 9, pp 221-245.

Larson, M. 1988. "Quantification of Beach Profile Change," Report No. 1008,
Department of Water Resources Engineering, University of Lund, Lund, Sweden.

Larson, M., Hanson, H., and Kraus, N. C. 1987. "Analytical Solutions of the
One-Line Model of Shoreline Change," Technical Report CERC-87-15, US Army
Engineer Waterways Experiment Station, Coastal Engineering Research Center,
Vicksburg, MS.

Larson, M., and Kraus, N. C. 1989a. "Prediction of Beach Fill Response to
Varying Waves and Water Level," Proceedings Coastal Zone '89, American Society
of Civil Engineers, pp 607-621.

1989b. "“SBEACH: Numerical Model for Simulating Storm-Induced
Beach Change," Report 1: Empirical Foundation and Model Development, Tech-
nical Report CERC-89-9, US Army Engineer Waterways Experiment Station,
Vicksburg, MS.

Larson, M., Kraus, N. C., and Byrnes, M. R. "SBEACH: Numerical Model for
Simulating Storm-Induced Beach Change, Report 2: Numerical Formulation and
Model Tests," Technical Report in preparation, US Army Engineer Waterways
Experiment Station, Coastal Engineering Research Center, Vicksburg, MS.

Larson, M., Kraus, N. C., and Hanson, H. "Schematized Numerical Model of

Three-Dimensional Beach Change," Abstracts 22nd International Coastal Engi-
neering Conference, in preparation, American Society of Civil Engineers.

Larson, M., Kraus, N. C., and Sunamura, T. 1988. "Beach Profile Change:
Morphology, Transport Rate, and Numerical Simulation," Proceedings of 21st
Coastal Engineering Conference, American Society of Civil Engineers, pp 1295-
1309.

Leenknecht, D. A., and Szuwalski, A. Z. 1990. "Automated Coastal Engineering
System: Technical Reference," US Army Engineer Waterways Experiment Station,
Coastal Engineering Research Center, Vicksburg, MS.

Le Méhauté, B., Wang, J. D., and Lu, C. C. 1983. "Wave Discretization for

Shore Line Processes," Journal of Waterway, Port, Coastal, and Ocean
Engineering, Vol 109, No. WW1, pp 63-78.

Mimura, N., Shimizu, T., and Horikawa, K. 1983. "Laboratory Study on the
Influence of Detached Breakwater on Coastal Change," Proceedings of Coastal
Structures '83, American Society of Civil Engineers, pp 740-752.

Mitchell, J. H. 1893. "On the Highest Waves in Water," Philosophic Magazine,
Series 5, No. 36, pp 430-437.

Moore, B. 1982. "Beach Profile Evolution in Response to Changes in Water
Level and Wave Height," M.S. Thesis, Department of Civil Engineering,

University of Delaware, Newark, DE.

183

Ozasa, H., and Brampton, A. H. 1980. "Mathematical Modeling of Beaches
Backed by Seawalls," Coastal Engineering, Vol 4, No. 1, pp 47-64.

Pelnard-Considere, R. 1956. "Essai de Theorie de 1’Evolution des Forms de
Rivage en Plage de Sable et de Galets," 4th Journees de 1’Hydraulique, Les
Energies de la Mer, Question III, No. 1, pp 289-298.

Perlin, M. 1979. "Predicting Beach Planforms in the Lee of a Breakwater,"

Proceedings Coastal Structures '/9, American Society of Civil Engineers,
pp 792-808.

Perlin, M., and Dean, R. G. 1978. "Prediction of Beach Planforms with

Littoral Controls," Proceedings of 16th Coastal Engineering Conference,
American Society of Civil Engineers, pp 1818-1838.

Pope, J., and Rowen, D. D. 1983. "Breakwaters for Beach Protection at

Lorain, OH," Proceedings of Coastal Structures ‘83, American Society of Civil
Engineers, pp /53-/68.

Saville, T. 1953. "Wave and Water Level Statistics for Lake Erie," Technical
Memorandum No. 37, Beach Erosion Board, US Army Corps of Engineers.

Shore Protection Manual. 1984. 4th ed., 2 Vols, US Army Engineer Waterways
Experiment Station, Coastal Engineering Research Center, US Government
Printing Office, Washington, DC.

Smith, E. R., and Kraus, N. C. "Laboratory Study of Macrofeatures of Wave
Breaking Over Bars and Reefs," Technical Report in preparation, US Army
Engineer Waterways Experiment Station, Coastal Engineering Research Center,
Vicksburg, MS.

Tanaka, N. 1988. "Part IV: Prediction Models of Shoreline Change," Chapter
5, Establishment of Simulation Conditions," In: K. Horikawa, Ed., Nearshore

Dynamics and Coastal Processes: Theory, Measurement, and Predictive Models,
University of Tokyo Press, Tokyo, Japan, pp 345-354.

US Army Engineer District, Buffalo. 1975. "Cooperative Beach Erosion
Control Project for lakeview Park, Lorain, Ohio," General Design Memorandum,
Phase II, Project Design, Buffalo, NY.

Vemulakonda, S. R., Scheffner, N. W., Earickson, J. A., and Chou, L. W. 1988.
"Kings Bay Coastal Processes Numerical Model," Technical Report CERC-88-3, US
Army Engineer Waterways Experiment Station, Coastal Engineering Research
Center, Vicksburg, MS.

Walker, J. R., Clark, D., and Pope, J. 1980. "A Detached Breakwater System

for Beach Protection," Proceedings 1/th Coastal Engineering Conference,
American Society of Civil Engineers, pp 1968-1987.

Walton, ‘T. “L.,° Liu, PP. L.-F., “and ‘Hands, "E. B. 1988"" “Shoreline at) Jetty, Due

to Cyclic and Random Waves," Proceedings of 21st Coastal Engineering
Conference, American Society of Civil Engineers, pp 1911-1921.

184

Watanabe, A. 1988. "Part III: Numerical Model of Beach Topography Change,"

Chapter 5, In: kK. Horikawa, Ed., Nearshore Dynamics and Coastal Processes:
Theory, Measurement, and Predictive Models, University of Tokyo Press, Tokyo,
Japan, pp 303-318.

185

mi wot’ te, D4tal teat seat rer,

: i we : Ns 0 8 fi * ee ed As Me SN THOR
ian depot A es Oo aS Sa raha sient .
De ER Re Cima
¥ ne 7 ht fe om
ONT) cont ann) ae a Meret aNYe Ta vial ‘ _
%
hh
7
» BPy*
o »
b Are Ge,’ The ae Kies
Peet aulm,” Perl Wale Folia, SUM
a) 7. LG @

APPENDIX A: REVIEW OF RELATED GENESIS STUDIES

1. This appendix provides a short review of selected publications
related to the Generalized Model for Simulating Shoreline Change (GENESIS) and
antecedent models. These works may be consulted for details on calculation
procedures, results of sensitivity tests, and hints on application of the
modeling system in applications. Specifications and recommendations given in
the present manual may differ from those in previous publications; the present
and future reports in the Coastal Engineering Research Center (CERC), US Army
Engineer Waterways Experiment Station, GENESIS series should be considered as
representing capabilities of the current modeling system and the procedure for
its operation.

2. In the following paragraphs, references are listed in chronological
order, and key points of the study are described.

3. Kraus and Harikai (1983)": This study introduces many of the basic
calculation algorithms used in GENESIS. The site for the field application,
Oarai Beach, Japan, provided an ideal environment for model testing and
refinement since a complete data base of wave measurements, shoreline change,
and other information was available. Sensitivity of the model to the input
wave data and its variability are examined, with emphasis on the length of the
time step and the averaging interval for wave data. A 6-hr time step is
recommended as standard for the coast for design studies. The longshore
variation in breaking wave height as produced by diffraction at a long
breakwater was measured, and the data used to verify the calculation procedure
for combined wave diffraction, refraction, shoaling, and breaking. Other
topics addressed are determination of the depth of closure, longshore sand
transport rate formula combining the effects of oblique wave incidence and
longshore gradient in wave height, use of a line source term for cross-shore
transport, verification of the bottom contour modification for the wave
calculation using field measurements of breaking wave angle influenced by
diffraction, and calibration and verification with measured wave and shoreline

change data. Previous work on the antecedent model is contained in a report

See References at the end of the main text.

(Kraus 1981) and an article written in Japanese (Kraus, Harikai, and Kubota
1981). A comprehensive summary of the model is given in Kraus (1988a-d).

4. Kraus (1983): This paper describes a verification of calculated
breaking wave height, breaking wave angle, and resultant shoreline change
using quantities measured in a physical model experiment of shoreline change
produced by a detached breakwater. The numerical model well reproduced the
time rate of shoreline change observed in the physical model, i.e., rapid
change at the initial stage of wave action followed by slower change in
approach to an equilibrium planform shape. Details of the breaking wave
calculation are described in an article in Japanese (Kraus 1982) and a
technical note (Kraus 1984).

5. Kraus, Hanson, and Harikai (1984): This article extends the
material in the paper of Kraus and Harikai (1983) to include the addition of a
massive detached breakwater, resulting in a model containing three sources of
diffraction, and a jetty, a groin, and a seawall. Other topics addressed are
qualitative correlation of measured frequencies of breaking wave height
alongshore and direction of the longshore current to the observed long-term
shoreline change, methods to produce wave time series for prediction and
simple estimates of bounds of expected variability in the wave data, sen-
sitivity of model results on changes in wave data.

6. Hanson and Kraus (1986a): This is the third and concluding article
in the series (Kraus and Harikai 1983; Kraus, Hanson, and Harikai 1984) on
shoreline change modeling and model development using the Oarai Beach data
set. The article focuses on evaluation of shore-protection alternatives with
the shoreline change model. Sensitivity of shoreline change to wave varia-
bility is examined in detail. It is found that shoreline change controlled by
wave diffraction is relatively insensitive to the sequence of wave input and
offshore wave direction, as opposed to the case of shoreline change on an open
coast (Le Méhauté, Wang, and Lu 1983). Alternative shore-protection plans
evaluated included a detached breakwater, beach nourishment, a groin field,
and combinations of these basic solution elements.

7. Hanson and Kraus (1986b): This report documents a rigorous imple-
mentation of a seawall within the framework of shoreline modeling theory and

includes discussion of assumptions, numerical formulation, example calcula-

tions, and computer programs for both explicit and implicit numerical solution
schemes.

8. Hanson (1987): This report, a doctoral dissertation, documents the
first version of the GENESIS modeling system. The concepts of longshore
calculation domains and wave energy windows are introduced, and major previous
and newly developed algorithms comprising GENESIS are described, including
multiple diffraction, sand bypassing and permeability of groins, and represen-
tation of beach fill. Results of numerous model sensitivity tests are
discussed and several case studies presented.

9. Kraus et al. (1988): This report describes a circa 1985 application
of GENESIS to the north New Jersey shore. The 8-mile-long reach contained 93
groins and involved development of strategies to deal with long simulation
times and long coastal reaches, as well as numerous refinements to GENESIS to
overcome many practical problems encountered with input of wave information
from an external wave transformation model and reliability of the internal
wave calculation under complex shoreline configurations. An arbitrary
threshold for longshore transport was set at a wave height of 20 cm to reduce
calculation time. The practical strategy of keying nearshore wave refraction
calculation results to a limited number of wave period-angle bands for unit
deepwater wave height was developed in this study.

10. Chu et al. (1987): This report describes the evaluation of several
shore-protection alternatives for a beach with a large tidal range and
composite grain size material.

11. Hanson and Larson (1987): This article gives comparisons of
analytical solutions as described in Larson, Hanson, and Kraus (1987) and
numerical predictions of GENESIS.

12. Kraus, Hanson, and Larson (1988): This article describes develop-
ment of an objective empirical criterion for predicting a threshold of
effective longshore sand transport rate. Comparisons of calculated shoreline
change with and without the threshold are made and results interpreted through
the general characteristics of the input wave time series.

13. Hanson (1989): This article presents an overview of the first

version of GENESIS, succinctly describing numerous technical and practical

features of the modeling system and presenting results of several sensitivity
tests and applications.

14. Gravens and Kraus (1989): Two different methods of representing
the effect of groins on the longshore sand transport rate are investigated.

15. Hanson, Kraus, and Nakashima (1989): This article presents results
of sensitivity tests on the procedure for calculating wave transmission at
detached breakwaters and the resultant shoreline change. The procedure is
verified using data from Holly Beach, Louisiana, the site of six detached
breakwaters of different materials and wave transmission characteristics.

Good agreement is found between calculated and measured shoreline position,
validating the calculation procedure and importance of wave transmission in
controlling shoreline change.

16. Gravens, Scheffner, and Hubertz (1989): This report describes an
application of GENESIS for the 9-mile reach of Atlantic coast between Asbury
Park and Manasquan, New Jersey. The modeled reach included jetties at two
inlets and 44 groins. A methodology to incorporate wave shadowing by Long
Island on the project shoreline was developed and implemented through use of a
nearshore wave transformation model. A procedure for selection of a represen-
tative 3-year time history of wave conditions from a 20-year hindcast data
base is presented. The potential impact of excavation of three nearshore
beach-fill borrow sites on shoreline change was investigated, and the concept
of a verification variability range introduced. The performance of six
proposed and four revised project design alternatives was evaluated over a
10-year simulation period using GENESIS to predict the planform evolution of
the beach.

17. Gravens (in preparation): This report describes an application of
GENESIS to estimate the potential impacts on adjacent shorelines resulting
from the construction of a new ocean inlet system between Anaheim Bay and the
Santa Ana River in southern California. In this study three simultaneous
independent wave sources (Northern Hemisphere swell, Southern Hemisphere
swell, and locally generated wind sea) were used to drive the shoreline change
model. In addition to estimating potential shoreline impacts, three project

mitigation design alternatives were quantitatively investigated.

APPENDIX B: BLANK INPUT FILES

This appendix gives blank copies of input files used to operate the
Generalized Model for Simulating Shoreline Change (GENESIS) Version 2.
START

HHH KKK EHH A KKH KK KKK AK KEKE KEK AK KK KK KEKE KKK REK KEKE KK

* INPUT FILE START.DAT TO GENESIS VERSION 2.0 *
KAKA AHK AA AHH KK HK HAHAHAHAHAHA AKA K EK IK IK KKK IER IERIE

[\cosadsbesaugous area As aaesee MOD EES E00 UP gta ete eee cerote a ee
A.1 RUN TITLE

A.2 INPUT UNITS (METERS=1; FEET=2): ICONV
A.3 TOTAL NUMBER OF CALCULATION CELLS AND CELL LENGTH: NN, DX

A.4 GRID CELL NUMBER WHERE SIMULATION STARTS AND NUMBER OF CALCULATION
CELLS (N = -1 MEANS N = NN): ISSTART, N

A.5 VALUE OF TIME STEP IN HOURS: DT

A.6 DATE WHEN SHORELINE SIMULATION STARTS
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501): SIMDATS

A.7 DATE WHEN SHORELINE SIMULATION ENDS OR TOTAL NUMBER OF TIME STEPS
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501): SIMDATE

A.8 NUMBER OF INTERMEDIATE PRINT-OUTS WANTED: NOUT

A.9 DATES OR TIME STEPS OF INTERMEDIATE PRINT-OUTS
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501, NOUT VALUES): TOUT(T1)

A.10 NUMBER OF CALCULATION CELLS IN OFFSHORE CONTOUR SMOOTHING WINDOW
(ISMOOTH = 0 MEANS NO SMOOTHING, ISMOOTH = N MEANS STRAIGHT LINE.
RECOMMENDED DEFAULT VALUE = 11): ISMOOTH

A.11 REPEATED WARNING MESSAGES (YES=1; NO=0): IRWM

A.12 LONGSHORE SAND TRANSPORT CALIBRATION COEFFICIENTS: Kl, K2

A.13 PRINT-OUT OF TIME STEP NUMBERS? (YES=1, NO=0): IPRINT

JostoSostads God 5SSS4 s65 decasesags WINDS). Geseessasade dogudecscagsdccuesone

B.1 WAVE HEIGHT CHANGE FACTOR. WAVE ANGLE CHANGE FACTOR AND AMOUNT (DEG)
(NO CHANGE: HCNGF=1, ZCNGF=1, ZCNGA=0): HCNGF, ZCNGF, ZCNGA

Figure Bl. START file template (Sheet 1 of 4)

.2 DEPTH OF OFFSHORE WAVE INPUT: DZ
.3. IS AN EXTERNAL WAVE MODEL BEING USED (YES=1; NO=0): NWD

.4 COMMENT: IF AN EXTERNAL WAVE MODEL IS NOT BEING USED, CONTINUE TO B.6
.5 NUMBER OF SHORELINE CALCULATION CELLS PER WAVE MODEL ELEMENT: ISPW

.6 VALUE OF TIME STEP IN WAVE DATA FILE IN HOURS (MUST BE AN EVEN MULTIPLE
OF, OR EQUAL TO DT): DTW

.7 NUMBER OF WAVE COMPONENTS PER TIME STEP: NWAVES
.8 DATE WHEN WAVE FILE STARTS (FORMAT YYMMDD: 1 MAY 1992 = 920501): WDATS

6 oot oe dadeakenebd Sos okeeseoee BEACH) <----o- esse eee 22 - oe oo =e eee
.1 EFFECTIVE GRAIN SIZE DIAMETER IN MILLIMETERS: D50

.2 AVERAGE BERM HEIGHT FROM MEAN WATER LEVEL: ABH
.3 CLOSURE DEPTH: DCLOS

soso e seSesogsscescenaase NONDIFFRACTING GROINS ----------------------=----D
.1 ANY NONDIFFRACTING GROINS? (NO=0, YES=1): INDG

.2 COMMENT: IF NO NONDIFFRACTING GROINS, CONTINUE TO E.
.3 NUMBER OF NONDIFFRACTING GROINS: NNDG

.4 GRID CELL NUMBERS OF NONDIFFRACTING GROINS (NNDG VALUES): IXNDG(T)
.5 LENGTHS OF NONDIFFRACTING GROINS FROM X-AXIS (NNDG VALUES): YNDG(I)

be ceceacegasasens DIFFRACTING (LONG) GROINS AND JETTIES ------------------E
.1 ANY DIFFRACTING GROINS OR JETTIES? (NO=0, YES=1): IDG

.2 COMMENT: IF NO DIFFRACTING GROINS, CONTINUE TO F.
.3 NUMBER OF DIFFRACTING GROINS/JETTIES: NDG

_4 GRID CELL NUMBERS OF DIFFRACTING GROINS/JETTIES (NDG VALUES): IXDG(I)
_5 LENGTHS OF DIFFRACTING GROINS/JETTIES FROM X-AXIS (NDG VALUES): YDG(I)
.6 DEPTHS AT SEAWARD END OF DIFFRACTING GROINS/JETTIES(NDG VALUES): DDG(I)
no scEeeaess baesnaaeeee ALL GROINS/JETTIES. -------------------------------F
.1 COMMENT: IF NO GROINS OR JETTIES, CONTINUE TO G.

.2 REPRESENTATIVE BOTTOM SLOPE NEAR GROINS: SLOPE2

.3 PERMEABILITIES OF ALL GROINS AND JETTIES (NNDG+NDG VALUES): PERM(T)

Figure Bl. (Sheet 2 of 4)

.4 IF GROIN OR JETTY ON LEFT-HAND BOUNDARY, DISTANCE FROM SHORELINE
OUTSIDE GRID TO SEAWARD END OF GROIN OR JETTY: YG1

.5 IF GROIN OR JETTY ON RIGHT-HAND BOUNDARY, DISTANCE FROM SHORELINE
OUTSIDE GRID TO SEAWARD END OF GROIN OR JETTY: YGN

96 SS6S esos ce cauer ee Gedeees DETACHED @BREARWATERG|§2/- em iseels- ae asa
.1 ANY DETACHED BREAKWATERS? (NO=0, YES=1): IDB

.2 COMMENT: IF NO DETACHED BREAKWATERS, CONTINUE TO H.
.3 NUMBER OF DETACHED BREAKWATERS: NDB

.4 ANY DETACHED BREAKWATER ACROSS LEFT-HAND CALCULATION BOUNDARY
(NO=0, YES=1): IDB1

.5 ANY DETACHED BREAKWATER ACROSS RIGHT-HAND CALCULATION BOUNDARY
(NO=0, YES=1): IDBN

.6 GRID CELL NUMBERS OF TIPS OF DETACHED BREAKWATERS
(2 * NDB - (IDB1+IDBN) VALUES): IXDB(1)

.7 DISTANCES FROM X-AXIS TO TIPS OF DETACHED BREAKWATERS
(1 VALUE FOR EACH TIP SPECIFIED IN G.6): YDB(I)

.8 DEPTHS AT DETACHED BREAKWATER TIPS (1 VALUE FOR EACH TIP
SPECIFIED IN G.6): DDB(I)

.9 DETACHED BREAKWATER TRANSMISSION COEFFICIENTS (NDB VALUES): TRANDB(1)

3005050000 Soba Pe aE aE EN eeare IAW AIG ee eee
.1 ANY SEAWALL ALONG THE SIMULATED SHORELINE? (YES=1; NO=0): ISW

.2 COMMENT: IF NO SEAWALL, CONTINUE TO I.
.3 GRID CELL NUMBERS OF START AND END OF SEAWALL (ISWEND = -1 MEANS
ISWEND = N): ISWBEG, ISWEND

nose sosnsncnes seesenosensees WING MGM “Sesosoognaa5sessososecsceccsue
.1 ANY BEACH FILLS DURING SIMULATION PERIOD? (NO=0, YES=1): IBF

.2 COMMENT: IF NO BEACH FILLS, CONTINUE TO K.
.3 NUMBER OF BEACH FILLS DURING SIMULATION PERIOD: NBF

-4 DATES OR TIME STEPS WHEN THE RESPECTIVE FILLS START
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501, NBF VALUES): BFDATS(1)

-) DATES OR TIME STEPS WHEN THE RESPECTIVE FILLS END
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501, NBF VALUES): BFDATE(T)

.6 GRID CELL NUMBERS OF START OF RESPECTIVE FILLS (NBF VALUES): IBFS(1)

Figure Bl. (Sheet 3 of 4)

I.7 GRID CELL NUMBERS OF END OF RESPECTIVE FILLS (NBF VALUES): IBFE(I)

I.8 ADDED BERM WIDTHS AFTER ADJUSTMENT TO EQUILIBRIUM CONDITIONS
(NBF VALUES): YADD(1)

(Open soo ee nos sossbesaponenes GOMMENTS) @o= a= aoe eee a eee K
* COMMENTS AND VERSION UPDATE INFORMATION PLACED HERE
* ADVERTISING RATES AVAILABLE

UBB eb oceooss apSoqccorsesseccas END OF START.DAT --=----------*-2--- == =e

Figure Bl. START file template (Sheet 4 of 4)

SHORL

FEE KKK KERTH HER WHER HHH HEHEHE HEHE HEHE FEM HEH HEHE AHHH AH FEAR HHH HK HK HEH HHH HH HEN

SHORELINE LOCATION MEASURED AT:

DATE: DX:
SEK SE SE SESE SESE EEE IESE SESE SESE SESE SE EEE IEEE EEE IEE TEE TE TE TE TE DEDEDE TE DE DE EE IE IEEE EEE ETE EEE EE EEE HE HE TE

wileticlieiel | lelecemelic: evelelleielh) | yeite:ie) jo ioe Miomeafperverie) \) evemejeniem | iuciietiouotel al uele lemecey: | Lielle cme em miwnericizeewe!
SpaoDo —GCoooum nono o Oooooe . oO 00-0 Soschod-0 "oom Orn pO soo OfO) 60-0) DLO" |) YOU 0 0.0
Tomo o ocoooo ooo omd "Sooo Sono o “wood oS oD D oo | oO nO do 710, DO oo £00005
sulstclishic) | cedleifeliejic! Neliejiefiel ef) | pefheiicyieijels © bisejoie) even) “elreieltemeniy | velieuememe) (a jl ielieinenteliaud) |e (ewelen elena dim ecjemnerome
euaviolicta) | Velredieievfers | Keleielfejjea? | telie feleiier | jebtesenclee) Fe lelceriejojie; | Hi ierjeicerjeiiey Mune elne. :oulejul Mente: jose ealenEme aes een one)
avis lolicttel em cllelitetichion | jelfesevere! delrejielie co §) vet shovlene: | MejieMosichiom ((uleMefteiialiiog@ cefeieneye: plegiene kelenaim Gedeiemome
TooMo cocOooonD “ocmoono oro co To ooo Coo ot od ato Potro. Ho Oag)O1G, ~ -0.D1 00.0
Yomood Pb motmood “oD oor. )-0'o Gosn) Wao oO oa) 10 Boho. pO. DD 8 OOOO) Oh Oo OBO OR) ONG 0.0

sie cele, ellel eile, ceiielewee:, | wekejevee) 9 <e'ls) elievie) jpeue eles) |) eel elledoumpmieMenio ue em Mi lmeilemelie cel ming lielsen ele

yotoo . ooo Ooodd. “Modmo ~“nooop. “ooo o nN ‘C/o \oro my VO O80. O68) MObo20sOIOL eT 0.080.090

Figure B2. SHORL file template

SEAWL

KKK KH KK KK HK KKK AK KAKA KKK KKK KKK HK IKK KEK KEK EK KKK EKER ER ERE ERE ER ER ER ERK

SEAWALL LOCATION MEASURED AT:

DATE: DXt
EK K KIKI IEICE IE TE TE DE TE TE TEE TE ETE TEE EEE IE IEEE ETE HE EE EK EHH EEE IEE IE A EE IE

eWfetielleie))) = je}e) 10) 10) (e . he leltelne ee eee epielie! . eXeoveve ee eee ee eee pce Ovo
eieericjieie! |) .0..9;"0 6; oe . eee ee eee . Sie | ee eete: fe \e.6, eae e)\e!-e[e 0) | fe} e;-0 fe..6
fewelere fel), | \eiejeie a, , 8] 0 'e/\e)¢ . ee aij ad desietfettes iets ‘repceite:ley ie Ste sevje, 6 felwwicelse: oe) sel teceise, ©
Chistiattagiss Nu elle cevteyie | s\sjelwe evsieieie: le.efeniele, | (ev eee? sie se 0) eiherie! |e oe eee sige olte/ta

. ©) fehreieele:| | (0, e's} .sice ed erecev es || eelienje,e, 8 cenjuyeieie;) je. ?e| eve lie:
eieiette ie 18) )=) (0, ele . ee ewe eee ee eee ee . se eee ©, jeje (0! elke ne: (oie
ayers) ele) | Tefelelene: Ve. leslie te eto fi feito temeite a jelverje ef 7) el .e,tentovvell) = Jeljetieie fevn) |) taie yerte Je . . .

elfen | eitel(e (elie) (ei epee!) Se eee | sel le\e} 0 (0) — ‘wice\ ‘er ies e: ja, syiee sreette}iejfe | ce telXej(u,ve) | (9 98 (eo) 181 ca,
eee ey) Melkelle serie ‘Te to jeilete oe fee.) ‘kelie ie je lenh te le’se) jolie eiisteie © Kelleliele jem ferelseiteliey Ye'lerejjeue

Figure B3. SEAWL file template

DEPTH

FEFK KKH HHA A HAHAH HAHAHAHA HEH HHA HHH HER HEH HH HH HH HK HK EK EK HAHA FEA EAE EHH ENE

DEPTHS ALONG REFERENCE LINE AT:

DATE: DX:
EK I IIE IE EI IEIIEIEIETE TE FETE TE TE DEDEDE TE FETE TEE TEE TEE FETE TE TEE HE FEE ETE TEE DEDEDE TE TE DEDEDE TE DEDEDE IE

Figure B4. DEPTH file template

WAVES

SEK KEKE KEK EE EK HEHEHE ER HK KHER HK EHH HEH HK KKH KH HH HHH HK HHH HHH HHA HAHAH KKK NK KKH

WAVES MEASURED AT: DATE:

FILE CONTAINS ONLY OFFSHORE WAVE DATA. DT: DX:
Soke kk ik kinins inn hinbinink oink dike oid bdo

EK KKE KKH HHH KHANH KH HHH HER KH HEHE HEH EMH HEH HK HHH HER HK HHH HHA HEHE HH HHH HK HH

WAVES MEASURED AT: DATE:

FILE CONTAINS OFFSHORE AND NEARSHORE WAVE DATA. DT: DX:
Yh oink doiniigkk iniiinnink inion biioinink hin ikki erie

eiiviiotevel elle; | jeliei elie ofa) Jelieiie) erelie) es, 10-0) oui, ‘elveliel(eliviis: «ele hee velier erie leeeheney( ere: oe ekeliena levleleme:eremumonemenemene
el avelielesie \ou Werlelieietteric) | s)lalieletfole|| toile! <e) (evjeme!) ceils! ios e(ieiie!§|eleselielie)je. J vebene:sfeie) Lefielecevevien) peje lemenelen mek ereriemonte
eiiei stlelleb ane t\ (e delleiteiene) snle jeer sis) “erlel sie) (ete) |ule,js)ie/(aife: le ueltettet/elfelvel§ (0 elsexielie) eh teisuigerie-ienel| imelienmeienenienemieiememenele)
a. ei ‘evte:ellaliel Melletletiatiate. Veljene ‘e/(ete)| jevievediove ne = woreseliolo vod to Veleliche sel sotelemevenom gone none geet: go nene ne melne me aemememememme
Ss lelleieliotie (s) ‘elles elects. | (elevieleveiie! jeje jelre) (ce) eit eile! eielicl(e) Leuelej.ecejiel lienieleseloyey were suelo em iene lee ewe meel emeuelmele
@ © elveties | “elle eis) es) |) festehere ie
Sjlatie tele elle) aelvejiciieiiattes ja) 'e)eepere!| elle) ere) el(el: Lepeieefeure Bie) sielieieiel jellevele rene; setts .ejje1e;1e)) (ne ejle!eseel meme emencns
cvieetic: ec eye (eljeie loliei\e\) e\e; eel elie) (relic ejvejele,| Je) etelbe: eile) yelte teenie el; (oe) feuelie ce .e)uireieie} ojse efniie) (ee eu euenmemeneniog cme
ol elie) oleiccie) | Geile’ 'w (0, \e'e) jefe) elie) ejo) je! eljel le) ie veil) Feljel.eljejjejiet, | ie! levcetielle) (ei) felieeh emo ieiamelse. e/seimejreh mareneuiesien selmi eliemememeate
oe © loelis je) “elle ae, 6101) (eve; ee) ee jeltelelieteves | fe, jee 0) jo el Whole neiie is) 10 fie) eMeherejrers enieike) 1 ene/s | .ehrelveieyeuemaelei Chose ae

iS elenelieeie. Verle «(ere le Free levejimvel | feiss elietielien etelsiellelici iellelelleliel te: j/.0) et ese) jelie> aie se nemene)iel wile ellesienesien mine Gemeneneis

Figure B5. WAVES file template

APPENDIX C: ERROR AND WARNING MESSAGES AND RECOVERY PROCEDURES

1. This appendix contains a list of error and warning messages that are
presently incorporated in the Generalized Model for Simulating Shoreline
Change (GENESIS). The error-trapping capability of new versions of GENESIS is
expected to be an active area of improvement in the modeling system, and an
expanded list of enhancements will be provided with new versions. As describ-
ed in the main text of this report, error messages indicate a condition that
will stop operation of the modeling system, whereas warning messages indicate
a potentially undesirable condition, but the calculation is allowed to
proceed.

2. Messages are given in alphabetical order in bold capital letters,
followed by an explanation and suggested error-recovery procedure. The

material is repetitive to allow the user to read without cross-reference.

Error Messages

3. ERROR. BAD BALANCE IN WAVE INPUT PARAMETERS CAUSING DLTZ TO BE
NEGATIVE. The depth of longshore sand transport (DLTZ is called "D,7," in
the main text) is proportional to the wave height with a correction for the
wave steepness. For actually occurring waves, this correction term is small,
but in situations for which the modeler fabricates a wave climate, the
correction term can inadvertently become unphysically large. This error
message will appear if the depth of longshore sand transport becomes negative
and is remedied by changing the wave height and/or period in the WAVES file to
represent physically reasonable waves.

4. ERROR. BEACH FILL IS OUTSIDE CALCULATION GRID. GENESIS has the
option of performing simulations over a portion of the beach through specifi-
cation of grid cell numbers other than 1 and N+l where the simulation
starts and ends. These numbers are entered on Line A.4 in the START file. To
facilitate use of the model, the coordinates of beach fills, as specified on
Lines I.6 and I.7, and structures are always given in the total coordinate
system. In this way the modeler does not have to change the coordinates of

operations as he or she targets one portion of the beach or another to be

modeled. The user must input only the part of the beach fill that appears
inside the portion of the beach presently being modeled. GENESIS transforms
the coordinates from the total coordinate system covering the whole beach to
the local system covering only the portion of beach. This error will appear
if the recalculated grid cell numbers fall outside the range of the local
grid. If the entire fill lies outside the grid, the error is remedied by
omitting corresponding values on Lines 1.4-1.8. If the fill is only partially
outside the grid, the error is remedied by setting IBFS on Line 1.6 equal to
the grid cell number where the simulation starts, if the right side of the
beach fill is outside the grid, or by setting IBFE equal to the grid cell
number where the simulation ends, if the left side of the seawall is outside
the grid.

5. ERROR. BOTH SEMI-INFINITE DETACHED BREAKWATER AND A DIFFRACTING
GROIN ON LEFT-HAND BOUNDARY NOT ALLOWED. Although GENESIS permits almost
arbitrary placement of structures, there are restrictions. One basic restric-
tion is that diffracting structures may not overlap. This means, for example,
that it is not possible to place a diffracting groin between two tips of a
detached breakwater. This error will appear if a detached breakwater is
specified on Line G.4 in the START file to cross the left-hand boundary and if
at the same time a diffracting groin is located in cell number 1 on Line E.4

in the START file. This error is remedied by any of three alternatives:

|»

Replace the diffracting groin with a nondiffracting groin.

Io"

Extend the diffracting groin to the detached breakwater, specify
that the detached breakwater does not cross the left-hand
boundary by setting IDBl = 0 on Line G.4 in the START file,
and at the same time specify that the detached breakwater starts
in cell number 1 on Line G.6 in the START file.

Move the diffracting groin so that it will no longer be inside
the detached breakwater, which means that IXDG(1) on Line E.4
in the START file must be greater than or equal to IXDB(1) on
ine G6.

6. ERROR. BOTH SEMI-INFINITE DETACHED BREAKWATER AND A DIFFRACTING
GROIN ON RIGHT-HAND BOUNDARY NOT ALLOWED. Although GENESIS permits almost

arbitrary placement of structures, there are restrictions. One basic restric-
tion is that diffracting structures may not overlap. This means, for example,
that it is not possible to place a diffracting groin between the two tips of a

detached breakwater. This error will appear if a detached breakwater is

specified on Line G.5 in the START file to cross the right-hand boundary and
if, at the same time, a diffracting groin is located in cell number N+l1 on
Line E.4 in the START file. The error is remedied in three ways:

Replace the diffracting groin with a nondiffracting groin.

Extend the diffracting groin to the detached breakwater, specify
that the detached breakwater does not cross the left-hand
boundary by setting IDBN = 0 on Line G.5 in the START file,
and at the same time specify that the detached breakwater ends
in cell number N+l1_ on Line G.6 in the START file.

ite)

Move the diffracting groin so that it will no longer be inside
the detached breakwater, which means that IXDG(NDG) (last
diffracting groin) on Line E.4 in the START file must be smaller
than or equal to IXDB(NDBTP) (last detached breakwater tip) on
Line G.6.

7. ERROR. DETACHED BREAKWATER CAN ONLY CONNECT TO A GROIN AT THE GROIN
TIP. Two of the basic structural elements in GENESIS, the jetty and the
detached breakwater, may be combined to produce complex configurations, e.g.,
spur jetties. However, one requirement is that the structures attach only at
tips. This error will appear if a detached breakwater is connected to a
diffracting groin other than at its tip and is remedied by moving the detached
breakwater tip to the end of the groin or by moving either of the two struc-
tures to separate them.

8. ERROR. DETACHED BREAKWATER ENDING ON OPEN LEFT-HAND BOUNDARY NOT
ALLOWED. Although GENESIS permits almost arbitrary placement of structures,
there are restrictions. One basic restriction is that a detached breakwater
cannot end on a grid boundary. Such placement implies that the first (or
last) energy window is outside the calculation grid and that wave energy
entering through it could not be determined. This message will appear if a
breakwater tip is in cell number 1 on Line G.6 in the START file and is
remedied by either considering the detached breakwater as being semi-infinite
by setting IDBl = 1 on Line G.4 in the START file or by specifying the first
cell number to be 2 or higher, as given on Line G.6 and setting IDBl =0O on
Line G.4 in the START file.

9. ERROR. DETACHED BREAKWATER ENDING ON OPEN RIGHT-HAND BOUNDARY NOT
ALLOWED. Although GENESIS permits almost arbitrary placement of structures,
there are restrictions. One basic restriction is that a detached breakwater

cannot end on the grid boundary. Such placement implies that the first (or

last) energy window would fall entirely outside the calculation grid and that
wave energy entering through it could not be determined. This error will
appear if a breakwater tip is specified in cell number N+1 on Line G.6 in
the START file and is remedied by either considering the detached breakwater
as being semi-infinite by setting IDBN = 1 on Line G.5 in the START file or
by specifying the last cell number to be N or less as given on Line G.6 and
setting IDBl = 0 on Line G.4 in the START file.

10. ERROR. DETACHED BREAKWATER TIP OUTSIDE CALCULATION GRID. GENESIS
has the option of performing simulations over a portion of the beach through
specification of grid cell numbers other than 1 and N+l where the simul-
ation starts and ends. These numbers are entered on Line A.4 in the START
file. To facilitate use of the model, the coordinates of diffracting groins,
as entered on Line E.4, and other structures are given in the total coordinate
system. In this way the modeler does not have to change the coordinates of
the structures as he or she targets one portion of the beach or another for
modeling. However, only those structures that appear inside the portion of
the beach presently being modeled should be specified. GENESIS transforms the
coordinates from the total coordinate system to the local system covering a
portion of the beach. This error is remedied by removing these grid cell
numbers from Line G.6 and the corresponding distances from x-axis and depths
on Lines G.7 and G.8, respectively. If the entire detached breakwater is
outside the grid, the corresponding transmission coefficient as specified on
Line G.9 must also be removed.

11. ERROR. DIFFRACTING GROIN OUTSIDE CALCULATION GRID. GENESIS has
the option of performing simulations over a portion of the beach through
specification of grid cell numbers other than 1 and N+l where the simula-
tion starts and ends. These numbers are entered on Line A.4 in the START
file. To facilitate use of the model, the coordinates of diffracting groins,
as entered on Line E.4, and other structures are given in the total coordinate
system. In this way the modeler does not have to change the coordinates of
the structures as he or she targets one portion of the beach or another for
modeling. However, only those structures that appear inside the portion of
the beach being modeled should be specified. GENESIS transforms the coor-

dinates from the total coordinate system to the local system covering a

portion of the beach. This error is remedied by omitting these grid cell
numbers from Line E.4 and the corresponding lengths and depths on Lines E.5
and E.6, respectively.

12. ERROR. DIFFRACTING STRUCTURES OVERLAP. Although GENESIS permits
almost arbitrary placement of structures, there are restrictions. One basic
restriction is that diffracting structures may not overlap. This means, for
example, that it is not possible to place a diffracting groin between the two
tips of a detached breakwater. This error will appear if a diffracting groin
is specified on Line E.4 in the START file to be located in a cell between the
two tips of a detached breakwater as specified on Line G.6. The error is

remedied by any of three alternatives:

Replace the diffracting groin with a nondiffracting groin.

Extend the diffracting groin to attach to the detached break-
water and at the same time divide the detached breakwater into
two detached breakwaters, specified on Lines G.3 and G.6-G.8,
each attaching to the tip of the groin, together constituting a
T-groin.

Move the diffracting groin so that it will no longer be inside
the detached breakwater as specified on Lines E.4 and G.6 in
the START file.

13. ERROR. END X-COORDINATE OF SEAWALL MUST BE GREATER THAN THE START
X-COORDINATE. In accordance with the seawall boundary condition, the calcu-
lated shoreline location is compared with the corresponding seawall location
in each cell within the extent of the seawall from cell number ISWBEG . to
cell number ISWEND , as specified on Line H.3 in the START file. If ISWBEG
is greater than ISWEND , the comparison and corrections would instead be done
for grid cells located between ISWEND and the end of the grid. This error
message will appear if ISWBEG is greater than ISWEND and is remedied by
correcting these numbers on Line H.3.

14. ERROR FOUND IN DEPIN. FILES DEPTH (AND WAVES) CONTAIN TOO FEW
VALUES. If an external wave transformation model is used to calculate the
nearshore wave conditions along the nearshore reference line, as specified by
setting NWD = 1 on Line B.3 in the START file, the corresponding depths and
wave information are obtained from the data files DEPTH and WAVES, respec-
tively. Following specifications of the total number of calculation cells on

Line A.3 and of the grid cell numbers where the simulation starts and ends on

Line A.4, the appropriate values will be read from these files. This error
message will appear if the end of the DEPTH file or WAVES file is prematurely
encountered and is remedied by adding more values to the two files, changing
the value of total number of calculation cells on Line A.3, or changing the
grid cell numbers where the calculation starts and/or ends on Line A.4.

15. ERROR FOUND IN KDGODA. KD CALCULATION DID NOT CONVERGE. The
diffracted breaking wave conditions are found by a search method that normally
converges within 5 to 10 iterations. However, to avoid the risk of being
trapped in an infinite loop, which, for example, can happen if the shoreline
advances past a detached breakwater, the search is stopped after 20 itera-
tions. This message will appear if the search procedure has not converged
within 20 iterations, and if the error persists, it probably signals a signi-
ficant flaw in the wave, depth, or structure configuration input data.

16. ERROR FOUND IN SHOIN. FILE SHORM CONTAINS TOO FEW VALUES.
Following specification of the total number of calculation cells on Line A.3
and of the grid cell numbers where the simulation starts and ends on Line A.4,
shoreline positions will be read from the data file SHORM in the subroutine
SHOIN. This message will appear if the end of the SHORM file is prematurely
encountered and is remedied by adding more values to the file, changing the
value of the total number of calculation cells on Line A.3, or changing the
grid cell numbers where the calculation starts and/or ends on Line A.4.

17. ERROR FOUND IN SHOIN. LAST SHORELINE BLOCK(S) OUTSIDE THE CALCU-
LATION GRID. Following specification of the total number of calculation cells
on Line A.3 and of the grid cell numbers where the simulation starts and ends
on Line A.4, shoreline positions will be read from the data file SHORL in the
subroutine SHOIN. This message will appear if the end of the SHORL file is
prematurely encountered and is remedied by adding more values to the file,
changing the value of the total number of calculation cells on Line A.3, or
changing the grid cell numbers where the calculation starts and/or ends on
Line A.4.

18. ERROR FOUND IN SWLIN. FILE SEAWL CONTAINS TOO FEW VALUES.
Following specification of the total number of calculation cells on Line A.3
and of the grid cell numbers where the simulation starts and ends on Line A.4,

seawall positions will be read from the data file SEAWL by subroutine SWLIN.

This message will appear if the end of the file is prematurely encountered in
the SEAWL file and is remedied by adding more values to the file, changing the
value of the total number of calculation cells on Line A.3, or changing the
grid cell numbers where the calculation starts and/or ends on Line A.4.

19. ERROR FOUND IN SWLIN. LAST SEAWALL BLOCK(S) OUTSIDE THE CALCU-
LATION GRID. Following specification of the total number of calculation cells
on Line A.3 and of the grid cell numbers where the simulation starts and ends
on Line A.4, seawall positions will be read from the data file SEAWL by sub-
routine SWLIN. This message will appear if the end of the file is prematurely
encountered in the SEAWL file and is remedied by adding more values to the
file, changing the value of the total number of calculation cells on Line A.3,
or changing the grid cell numbers where the calculation starts and/or ends on
Line A.4.

20. ERROR FOUND IN WAVIN. FILE WAVES CONTAINS TOO FEW NEARSHORE WAVE
DATA POINTS. Following specification of the total number of calculation cells
on Line A.3 and of the grid cell numbers where simulation starts and ends on
Line A.4, offshore and nearshore wave data will be read from the data file
WAVES by subroutine WAVIN. This message will appear if the end of the WAVES
file is prematurely encountered while reading the nearshore wave data and is
remedied by adding more values to the file, changing the value of the total
number of calculation cells on Line A.3, or changing the grid cell numbers
where the calculation starts and/or ends on Line A.4.

21. ERROR. GROIN CONNECTED TO A DETACHED BREAKWATER MUST BE CLASSIFIED
AS A DIFFRACTING GROIN. Two of the basic structural elements in GENESIS, the
groin and the detached breakwater, may be combined to produce more complex
configurations, e.g., spur jetties: However, one requirement is that the
groin be specified as diffracting. This error will appear if a detached
breakwater is attached to a nondiffracting groin and is remedied by removing
values specifying a nondiffracting groin on Lines D.4 and D.5 in the START
file and placing them on Lines E.4-E.6 corresponding to a diffracting groin.

22. ERROR. GROIN NEXT TO GRID BOUNDARY. The longshore sand transport
rate depends on the angle between the wave crests and the shoreline. To
calculate the shoreline orientation, the shoreline location in two adjacent

calculation cells is needed. At the location of groins, a straight line

between the two cells on either side of the structure is not a good represent-
ation of the local shoreline orientation. Instead, the shoreline orientation
on the updrift or upwave side is used for calculating the transport rate. If
the groin is on a boundary, the transport rate is calculated as a boundary
condition as described in Part IV. Thus, the groin must be placed either on a
boundary or at least two calculation cells away from it. This message will
appear if a groin is placed one calculation cell away from either end of the
numerical grid. The error is remedied by moving the groin at least one cell
away from the end of grid or by moving the end of the grid at least one cell
away from the groin. (See Line D.4 for nondiffracting groins and Line E.4 for
diffracting groins.)

23. ERROR. GROINS MUST BE SEPARATED BY AT LEAST TWO CALCULATION CELLS.
The longshore sand transport rate depends on the angle between the wave crests
and the shoreline. To calculate the shoreline orientation, the shoreline
location in two adjacent calculation cells is needed. At the location of
groins, a straight line between the two cells on either side of the structure
is not believed to be a good representation of the local shoreline orienta-
tion. Instead, the shoreline orientation on the updrift or upwave side is
used for calculating the transport rate, requiring at least two cells separat-
ing each pair of groins. This message will appear if two groins are placed
with only one calculation cell between them and is remedied by moving one of
the groins at least one cell farther away from the other groin. (See Line D.4
for nondiffracting groins and Line E.4 for diffracting groins.)

24. ERROR IN CALCULATION OF BREAKING WAVE HEIGHT. THE WAVE DID NOT
BREAK. The undiffracted breaking wave conditions are found by a search method
that normally converges within 6 to 8 iterations. However, to avoid the risk
of being trapped in an infinite loop, the search is stopped after 20 itera-
tions. This error message will appear if the search procedure has not
converged within 20 iterations and may be remedied by changing what is
probably an unphysical wave height with respect to the nearshore depth (or
vice versa). If the error persists, it probably signals a significant flaw in
the wave, depth, or structure configuration input.

25. ERROR. INCORRECT FORMAT FOR BEACH FILL DATES. The dates when

beach fills start are specified values of BFDATS entered on Line I.4 in the

START file. The dates when the beach fills end are specified by values of
BFDATE entered on Line 1.5. Each date must be entered as one number in the
format YYMMDD. This error message will appear if, for any of these dates, the
number of the day is greater than 31 or if the number of the month is greater
than 12.

26. ERROR. INCORRECT FORMAT OF SIMULATION START DATE. The date
specifying when the calculation starts is contained in the value of SIMDATS
entered on Line A.6 in the START file. This date must be entered as one
number in the format YYMMDD. This message will appear if the number of the
day is greater than 31 or if the number of the month is greater than 12.

27. ERROR. SEAWALL IS OUTSIDE CALCULATION GRID. GENESIS has the
option of performing simulations over a portion of the beach through specifi-
cation of grid cell numbers other than 1 and N+l where the simulation
starts and ends. These numbers are entered on Line A.4 in the START file. To
facilitate use of the model, the coordinates of seawalls, as specified on Line
H.3, and other structures are always given in the total coordinate system. In
this way the modeler does not have to change the coordinates of the structures
if he or she targets one portion of the beach or another for modeling.
However, the user must input only that part of the seawall that appears inside
the portion of the beach presently being modeled. GENESIS transforms the
coordinates from the total coordinate system to the local system covering a
portion of the beach. This message will appear if the recalculated grid cell
numbers fall outside the range of the local grid and is remedied by setting
ISWBEG , on Line H.3, equal to the grid cell number where the simulation
starts if the right side of the seawall is outside the grid or by setting
ISWEND equal to the grid cell number where the simulation ends if the left
side of the seawall is outside the grid.

28. ERROR. SIMULATION ENDING DATE MUST BE GREATER THAN THE STARTING
DATE. The ending date of the simulation as specified on Line A.7 in the START
file must be given as one number in format YYMMDD. If an incorrect format is
used, GENESIS may interpret the ending date as earlier than the start date.

29. ERROR. SMALL GROIN OUTSIDE CALCULATION GRID. GENESIS has the
option of performing simulations over a portion of the beach through specifi-

cation of grid cell numbers other than 1 and N+l where the simulation

starts and ends. These numbers are entered on Line A.4 in the START file. To
facilitate use of the model, the coordinates of small groins, as specified on
Line D.4, and other structures are given in the total coordinate system. In
this way the modeler does not have to change the coordinates of the structures
as he or she targets one portion of the beach or another for modeling.
However, only those structures that appear inside the portion of the beach
being modeled should be specified. GENESIS transforms the coordinates from
the total coordinate system to the local system covering a portion of the
beach. This message will appear if the recalculated grid cell numbers fall
outside the range of the local grid and is remedied by omitting these grid
cell numbers from Line D.4 and the corresponding lengths on Line D.5.

30. ERROR. TOO MANY BEACH FILLS. Many arrays in the FORTRAN code
depend on the number of beach fills. The largest possible number is 50. This
error message will appear if NBF on Line 1.3 is greater than 50 and is
remedied by reducing NBF accordingly. As NBF is changed, corresponding
changes must be introduced on Lines 1.4 and I.5, as the number of data entries
on these lines must correspond to the number of beach fills as specified on
Line I.3. The number of beach fills can be reduced by splitting up the beach
in portions and then performing the simulations for one portion of the beach
at a time.

31. ERROR. TOO MANY DETACHED BREAKWATERS. Many arrays in the FORTRAN
code depend on the number of detached breakwaters. The largest possible
number is 20. This message will appear if NDB on Line G.3 is greater than
20 and is remedied by reducing NDB accordingly. As NDB is changed, cor-
responding changes must be introduced on Lines G.4 to G.9, as the number of
data entries on these lines must correspond to the number of structures as
specified on Line G.3. The number of structures can be reduced by splitting
up the beach in portions and then performing the simulations for one portion
of the beach at a time.

32. ERROR. TOO MANY DIFFRACTING GROINS. Many arrays in the FORTRAN
code depend on the number of diffracting groins. The largest possible number
is 20. This error will appear if NDG on Line E.3 is greater than 20 and is
remedied by reducing NDG accordingly. As NDG is changed, corresponding

changes must be introduced on Lines E.4 to E.6, as the number of data entries

c10

on these lines must correspond to the number of structures as specified on
Line E.3. The number of structures can be reduced by splitting up the beach
in portions and then performing the simulations for one portion of the beach
at the time.

33. ERROR. TOO MANY INTERMEDIATE PRINTOUTS REQUESTED. Many arrays in
the FORTRAN code depend on the number of requested printouts. The largest
possible number is 30. This error message will appear if the variable NOUT
on Line A.8 in the START file is greater than 30 and is remedied by reducing
NOUT accordingly.

34. ERROR. TOO MANY NONDIFFRACTING GROINS. Many arrays in the FORTRAN
code depend on the number of nondiffracting groins. The largest possible
number is 50. This error message will appear if NNDG on Line D.3 is greater
than 50 and is remedied by changing NNDG accordingly. As NNDG is changed,
corresponding changes must be introduced on Lines D.4 and D.5, as the number
of data entries on these lines must correspond to the number of structures as
specified on Line D.3. The number of structures can be reduced by splitting
up the beach in portions and then performing the simulations for one portion
of the beach at a time.

35. ERROR. TOO MANY SHORELINE CELLS. Many arrays in the FORTRAN code
depend on the number of shoreline cells alongshore. The largest possible
number is 600. This message will appear if NN on Line A.3 in the START file
is greater than 600 and is remedied by reducing NN accordingly.

36. ERROR. WAVE DATA FILE STARTS LATER THAN THE SIMULATION. If the
simulation starts later than the starting date of the wave data file as
specified on Line B.8, GENESIS will read over lines in the WAVES file until
the wave input corresponding to the simulation starting date is found. This
date must be given as one number in the format YYMMDD. If the wave data file
is specified to start later than the simulation, the corresponding date will
never be found.

37. ERROR. WRONG VALUE OF "ICONV". GENESIS performs calculations in
length units of either meters or feet according to the value of ICONV
entered on Line A.2 in the START file. This message will appear if any other

number but 1 (meters) or 2 (feet) is given for ICONV.

Cll

Warning Messages

38. WARNING. INPUT WAVE ALREADY BROKEN. In the use of GENESIS, wave
transformation from deep to shallow water can be performed using an internal
or an external wave transformation model. If an external wave model is used,
wave transformation over the actual (irregular) bathymetry is calculated
starting at the defined offshore depth. Resultant values of wave height and
direction alongshore at a depth such that wave breaking has not yet occurred
are placed in a file (by external manipulations by the modeler) for input to
the internal wave model of GENESIS. These depths (for example, the depths in
each wave calculation cell at the nominal 6-m or 20-ft contour) define a
"nearshore reference line" from which the internal wave model takes over grid
cell by grid cell to bring the waves to the breakpoint. This message is
issued if the wave height on the reference line exceeds the depth-limited wave
height as given by the relation H, = yD, . This condition is remedied by
either decreasing the input wave height in the WAVES file or by increasing the
reference depth in the DEPTH file.

39. WARNING. THE STABILITY PARAMETER IS ____. The numerical stabil-
ity of the calculation scheme is expressed by the stability parameter Rg .
The magnitude of the stability parameter also indicates the numerical accuracy
of the solution. GENESIS calculates the value of Rg at each time step at
each grid point alongshore and determines the maximum value. If Rg > 5 for
any grid point, a message is issued. The condition can be eliminated by
either decreasing the time step DT at Line A.5 or by increasing the grid
cell size DX at Line A.3. Normally the time step is reduced since con-
siderable effort is involved in developing a grid.

40. WARNING. TRANSPORT CALCULATIONS DIFFER. A seawall imposes a
constraint on the position of the shoreline since the shoreline cannot move
landward of the wall. GENESIS first calculates longshore sand transport rates
along the beach based on the assumption that the calculated amount of sand is
available for transport. At grid cells where the seawall constraint is vio-
lated, the shoreline position and the transport rate are adjusted. Corres-

ponding quantities in neighboring cells are also adjusted to preserve sand

C12

volume and the direction of transport. The transport calculation has to be
performed in the same direction as the direction of transport. Therefore, two
independent algorithms, one calculating the transport rates from grid cells

1 to N+ 1 and one calculating in reverse order, are needed. These algo-
rithms should give the same transport rate. However, for large values of the
stability parameter or because of the presence of detached breakwaters,
especially if they are transmissive, the two algorithms may give slightly
different results. This message is issued if the difference in the two
calculated transport rates is greater than 0.0005 m?/sec at any cell along-
shore. This condition is remedied by decreasing the stability ratio, which in
turn is done by decreasing the time step, increasing the grid cell size, or
decreasing the wave height. Extremely high angles of wave incidence may also
produce this error. In addition to the reporting the actual transport rate
difference, the shoreline change resulting from this difference is also
reported.

41. WARNING. UNPHYSICAL DEEPWATER WAVE STEEPNESS. The input offshore
wave data may be manipulated, for example, to investigate model sensitivity or
the effect of extreme conditions. In these investigations the wave height is
often increased, and, if care is not taken, it is possible to accidentally
specify waves of unphysically large steepness. GENESIS checks that the
offshore wave steepness does not exceed the value of 0.142, and, if it does,
reduces the deepwater wave height to satisfy this condition. This message is
issued if the wave steepness exceeds 0.142 and is remedied by decreasing the

wave height or increasing the input wave period in the WAVES file.

Error Messages Issued by the Computer

42. Even though much effort was devoted to making the data input proce-
dure as straightforward and error-free as possible, it is inevitable that
mistakes will made in preparing input files. As a result of mismatch errors
between read instructions in GENESIS and the improper content of a data file,
a computer will issue error messages that may be obscure and difficult to
interpret. Experience indicates that the most common input errors occur in

the START file. In this case the computer system may issue a message about an

c13

input error in Unit 10, which means the START file, and will also give the

line number in the FORTRAN code where the error occurs.

C14

APPENDIX D: INPUT AND OUTPUT FILES FOR CASE STUDY

43. This appendix gives the contents of the input files used for the

case study and the resultant output files.

START Files
File START_INIT representing the first version of the START file.
A---------------------------- MODEL SETUP ------------------------------ A

A.1 RUN TITLE
LAKEVIEW PARK CASE STUDY, MAY-JUNE 1989, PRELIMINARY RUN
A.2 INPUT UNITS (METERS=1; FEET=2): ICONV
2
A.3 TOTAL NUMBER OF CALCULATION CELLS AND CELL LENGTH: NN, DX
LOE 2I5)
A.4 GRID CELL NUMBER WHERE SIMULATION STARTS AND NUMBER OF CALCULATION
CELLS (N = -1 MEANS N = NN): ISSTART, N

1 -l
A.5 VALUE OF TIME STEP IN HOURS: DT
6

A.6 DATE WHEN SHORELINE SIMULATION STARTS
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501): SIMDATS
771001
A.7 DATE WHEN SHORELINE SIMULATION ENDS OR TOTAL NUMBER OF TIME STEPS
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501): SIMDATE
771024
A.8 NUMBER OF INTERMEDIATE PRINT-OUTS WANTED: NOUT
0)
A.9 DATES OR TIME STEPS OF INTERMEDIATE PRINT-OUTS
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501, NOUT VALUES): TOUT(1)

A.10 NUMBER OF CALCULATION CELLS IN OFFSHORE CONTOUR SMOOTHING WINDOW
(ISMOOTH = 0 MEANS NO SMOOTHING, ISMOOTH = N MEANS STRAIGHT LINE.
RECOMMENDED VALUE = 11): ISMOOTH

Naat EPEAT WARNING MESSAGES (YES=1; NO=0): IRWM

A.12 ae SAND TRANSPORT CALIBRATION COEFFICIENTS: Kl, K2

AIS SIA On OF TIME STEP NUMBERS? (YES=1, NO=0): IPRINT

ae Sood psd adeneoesoed aes sdeos PINGS) Ueseaseeuee sas cae pa aeaeoa Se ocooue B

B.1 WAVE HEIGHT CHANGE FACTOR. WAVE ANGLE CHANGE FACTOR AND AMOUNT (DEG)
(NO CHANGE: HCNGF=1, ZCNGF=1, ZCNGA=0): HCNGF, ZCNGF, ZCNGA

Ii dbs 0)

B.2 DEPTH OF OFFSHORE WAVE INPUT: DZ
30

B.3 IS AN EXTERNAL WAVE MODEL BEING USED (YES=1; NO=0): NWD
0

COMMENT: IF AN EXTERNAL WAVE MODEL IS NOT BEING USED, CONTINUE TO B.6
NUMBER OF SHORELINE CALCULATION CELLS PER WAVE MODEL ELEMENT: ISPW

VALUE OF TIME STEP IN WAVE DATA FILE IN HOURS (MUST BE AN EVEN MULTIPLE
OF, OR EQUAL TO DT): DTW

NUMBER OF WAVE COMPONENTS PER TIME STEP: NWAVES

DATE WHEN WAVE FILE STARTS (FORMAT YYMMDD: 1 MAY 1992 = 920501): WDATS
770101

wo 2-2-2 2 eee eee --- BEACH ---------------------------------€
EFFECTIVE GRAIN SIZE DIAMETER IN MILLIMETERS: D50
0.4
AVERAGE BERM HEIGHT FROM MEAN WATER LEVEL: ABH
8
CLOSURE DEPTH: DCLOS
16

Sodascodessoandesdsuadas NONDIBPRACTING) GROINS) == =< eee meee o-oo

ANY NONDIFFRACTING GROINS? (NO=0, YES=1): INDG

cone: IF NO NONDIFFRACTING GROINS, CONTINUE TO E.

NUMBER OF NONDIFFRACTING GROINS: NNDG

aah CELL NUMBERS OF NONDIFFRACTING GROINS (NNDG VALUES): IXNDG(1)
Tenens OF NONDIFFRACTING GROINS FROM X-AXIS (NNDG VALUES): YNDG(T)
164 360

ScdddcugsuocscGes DIFFRACTING (LONG) GROINS AND JETTIES ---------------oeB

ANY DIFFRACTING GROINS OR JETTIES? (NO=0, YES=1): IDG

poet: IF NO DIFFRACTING GROINS, CONTINUE TO F.

NUMBER OF DIFFRACTING GROINS/JETTIES: NDG

GRID CELL NUMBERS OF DIFFRACTING GROINS/JETTIES (NDG VALUES): IXDG(I)
LENGTHS OF DIFFRACTING GROINS/JETTIES FROM X-AXIS (NDG VALUES): YDG(1)

DEPTHS AT SEAWARD END OF DIFFRACTING GROINS/JETTIES(NDG VALUES): DDG(I)

Spaessbosseaeassnes5 See ALL GROINS/JETRDIES w= = aoe eee ome ees

COMMENT: IF NO GROINS OR JETTIES, CONTINUE TO G.

REPRESENTATIVE BOTTOM SLOPE NEAR GROINS: SLOPE2

0.056 (1:18)

PERMEABILITIES OF ALL GROINS AND JETTIES (NNDG+NDG VALUES): PERM(1)
0.0 0.0

IF GROIN OR JETTY ON LEFT-HAND BOUNDARY, DISTANCE FROM SHORELINE
OUTSIDE GRID TO SEAWARD END OF GROIN OR JETTY: YG1

IF GROIN OR JETTY ON RIGHT-HAND BOUNDARY, DISTANCE FROM SHORELINE
OUTSIDE GRID TO SEAWARD END OF GROIN OR JETTY: YGN

240

G----- srr rere rrr rrr cece DETACHED BREAKWATERS -------------------------- G
G.1 ANY DETACHED BREAKWATERS? (NO=0, YES=1): IDB
1
G.2 COMMENT: IF NO DETACHED BREAKWATERS, CONTINUE TO H.
G.3 NUMBER OF DETACHED BREAKWATERS: NDB
3
G.4 ANY DETACHED BREAKWATER ACROSS LEFT-HAND CALCULATION BOUNDARY
(NO=0, YES=1): IDB1
0
G.5 ANY DETACHED BREAKWATER ACROSS RIGHT-HAND CALCULATION BOUNDARY
(NO=0, YES=1): IDBN
0
G.6 GRID CELL NUMBERS OF TIPS OF DETACHED BREAKWATERS
(2 * NDB - (IDB1+IDBN) VALUES): IXDB(I1)
2yel2 18 28 34 44
G.7 DISTANCES FROM X-AXIS TO TIPS OF DETACHED BREAKWATERS
(1 VALUE FOR EACH TIP SPECIFIED IN G.6): YDB(I)
445 477 498 509 DZD 1512)
G.8 DEPTHS AT DETACHED BREAKWATER TIPS (1 VALUE FOR EACH TIP
SPECIFIED IN G.6): DDB(I)
10 10.5 Tea deo) TIES Ue ALIS
G.9 DETACHED BREAKWATER TRANSMISSION COEFFICIENTS (NDB VALUES: TRANDB(1)

0 0 0
Henin oSr pase esrstt oa es SEAWALLS~ ------------------------------- H
H.1 ANY SEAWALL ALONG THE SIMULATED SHORELINE? (YES=1; NO=0): ISW

H.2 COMMENT: IF NO SEAWALL, CONTINUE TO I.
H.3 GRID CELL NUMBERS OF START AND END OF SEAWALL (ISWEND = -1 MEANS
ISWEND = N): ISWBEG, ISWEND

I hal!
Woo Se CQ SRO BOOB OS RSG SoCo BEACH FILLS ----------------------------- it
I.1 ANY BEACH FILLS DURING SIMULATION PERIOD? (NO=0, YES=1): IBF

I.2 COMMENT: IF NO BEACH FILLS, CONTINUE TO K.
I.3 NUMBER OF BEACH FILLS DURING SIMULATION PERIOD: NBF

I.4 DATES OR TIME STEPS WHEN THE RESPECTIVE FILLS START
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501, NBF VALUES): BFDATS(1)

I.5 DATES OR TIME STEPS WHEN THE RESPECTIVE FILLS END
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501, NBF VALUES): BFDATE(T)

I.6 GRID CELL NUMBERS OF START OF RESPECTIVE FILLS (NBF VALUES): IBFS(1)
I.7 GRID CELL NUMBERS OF END OF RESPECTIVE FILLS (NBF VALUES): IBFE(1)

1.8 ADDED BERM WIDTHS AFTER ADJUSTMENT TO EQUILIBRIUM CONDITIONS
(NBF VALUES): YADD(1)

File START_CAL representing the calibrated version of the START file.

A---- 2-25 ne rence ctr recrcc ss MODEL SETUP) ----------------2---------- 0 - A
A.1 RUN TITLE
LAKEVIEW PARK CASE STUDY, MAY-JUNE 1989, CALIBRATION
A.2 INPUT UNITS (METERS=1; FEET=2): ICONV
2
A.3 TOTAL NUMBER OF CALCULATION CELLS AND CELL LENGTH: NN, DX
49 25
A.4 GRID CELL NUMBER WHERE SIMULATION STARTS AND NUMBER OF CALCULATION
CELLS (N = -1 MEANS N = NN): ISSTART, N
1, =
A.5 VALUE OF TIME STEP IN HOURS: DT
0.3
A.6 DATE WHEN SHORELINE SIMULATION STARTS
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501): SIMDATS
771024
A.7 DATE WHEN SHORELINE SIMULATION ENDS OR TOTAL NUMBER OF TIME STEPS
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501): SIMDATE
781009
A.8 NUMBER OF INTERMEDIATE PRINT-OUTS WANTED: NOUT
0
A.9 DATES OR TIME STEPS OF INTERMEDIATE PRINT-OUTS
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501, NOUT VALUES): TOUT(I)

A.10 NUMBER OF CALCULATION CELLS IN OFFSHORE CONTOUR SMOOTHING WINDOW
(ISMOOTH = 1 MEANS NO SMOOTHING, ISMOOTH = N MEANS STRAIGHT LINE.
RECOMMENDED VALUE = 11): ISMOOTH

eal Bepies WARNING MESSAGES (YES=1; NO=0): IRWM

A.12 saaeah SAND TRANSPORT CALIBRATION COEFFICIENTS: Kl, K2

A.13 cee ae OF TIME STEP NUMBERS? (YES=1, NO=0): IPRINT

cae ss bac ebbossbososeeeosseseee WANES) ee )2 ote oie eee ee B

B.1 WAVE HEIGHT CHANGE FACTOR. WAVE ANGLE CHANGE FACTOR AND AMOUNT (DEG)
(NO CHANGE: HCNGF=1, ZCNGF=1, ZCNGA=0): HCNGF, ZCNGF, ZCNGA
1G) JE)
B.2 DEPTH OF OFFSHORE WAVE INPUT: DZ
30
B.3 IS AN EXTERNAL WAVE MODEL BEING USED (YES=1; NO=0): NWD
0
B.4 COMMENT: IF AN EXTERNAL WAVE MODEL IS NOT BEING USED, CONTINUE TO B.6
B.5 NUMBER OF SHORELINE CALCULATION CELLS PER WAVE MODEL ELEMENT: ISPW

B.6 VALUE OF TIME STEP IN WAVE DATA FILE IN HOURS (MUST BE AN EVEN MULTIPLE
OF, OR EQUAL TO DT): DTW
6

B.7 NUMBER OF WAVE COMPONENTS PER TIME STEP: NWAVES
il

DATE WHEN WAVE FILE STARTS (FORMAT YYMMDD: 1 MAY 1992 = 920501): WDATS
770101

DOS OSS O GUIS RSS OOS SSO Sa BEAGH - Ww nm erin mn nie mini = = = = i nin G
EFFECTIVE GRAIN SIZE DIAMETER IN MILLIMETERS: D50
0.4
AVERAGE BERM HEIGHT FROM MEAN WATER LEVEL: ABH
8
CLOSURE DEPTH: DCLOS
16

56 Sob SSSR BES Coe HNBOBeS NONDIFFRACLINGICGROUNS§e= => 225 s=2=- == -25ase)

ANY NONDIFFRACTING GROINS? (NO=0, YES=1): INDG

ee IF NO NONDIFFRACTING GROINS, CONTINUE TO E.

NUMBER OF NONDIFFRACTING GROINS: NNDG

aes CELL NUMBERS OF NONDIFFRACTING GROINS (NNDG VALUES): IXNDG(1)
TENGTiS OF NONDIFFRACTING GROINS FROM X-AXIS (NNDG VALUES): YNDG(I)
164 360

scasecSsosecbacass DIFFRACTING (LONG), GROINS ANDMJETTTESH@s>--25-—-e55—=2-F

ANY DIFFRACTING GROINS OR JETTIES? (NO=0, YES=1): IDG

CORRENTE: IF NO DIFFRACTING GROINS, CONTINUE TO F.

NUMBER OF DIFFRACTING GROINS/JETTIES: NDG

GRID CELL NUMBERS OF DIFFRACTING GROINS/JETTIES (NDG VALUES): IXDG(1)
LENGTHS OF DIFFRACTING GROINS/JETTIES FROM X-AXIS (NDG VALUES): YDG(I1)

DEPTHS AT SEAWARD END OF DIFFRACTING GROINS/JETTIES(NDG VALUES): DDG(1)

seosesacsbeouh oseecesne AVUMCROUNS/E RTGS 9a. 2= sei = seen aia eye enero

COMMENT: IF NO GROINS OR JETTIES, CONTINUE TO G.

REPRESENTATIVE BOTTOM SLOPE NEAR GROINS: SLOPE2

0.056 (1:18)

PERMEABILITIES OF ALL GROINS AND JETTIES (NNDG+NDG VALUES): PERM(T1)
0.0 0.0

IF GROIN OR JETTY ON LEFT-HAND BOUNDARY, DISTANCE FROM SHORELINE
OUTSIDE GRID TO SEAWARD END OF GROIN OR JETTY: YG1

IF GROIN OR JETTY ON RIGHT-HAND BOUNDARY, DISTANCE FROM SHORELINE
OUTSIDE GRID TO SEAWARD END OF GROIN OR JETTY: YGN

180

ddasnesddacosassadcsaanad DETACHED) BREAKRWATERS == 9 2)o2 22) eee et

ANY DETACHED BREAKWATERS? (NO=0, YES=1): IDB

COMMENT: IF NO DETACHED BREAKWATERS, CONTINUE TO H.

NUMBER OF DETACHED BREAKWATERS: NDB

ANY DETACHED BREAKWATER ACROSS LEFT-HAND CALCULATION BOUNDARY
(NO=0, YES=1): IDB1

G.5 ANY DETACHED BREAKWATER ACROSS RIGHT-HAND CALCULATION BOUNDARY
(NO=0, YES=1): IDBN
0
G.6 GRID CELL NUMBERS OF TIPS OF DETACHED BREAKWATERS
(2 * NDB - (IDB1+IDBN) VALUES): IXDB(I)
Dieli2. 18 28 36 46
G.7 DISTANCES FROM X-AXIS TO TIPS OF DETACHED BREAKWATERS
(1 VALUE FOR EACH TIP SPECIFIED IN G.6): YDB(I)
445 477 498 509 B22) BY25)
G.8 DEPTHS AT DETACHED BREAKWATER TIPS (1 VALUE FOR EACH TIP
SPECIFIED IN G.6): DDB(I)
HOP UORS Ia aL ee Gy hey
G.9 DETACHED BREAKWATER TRANSMISSION COEFFICIENTS (NDB VALUES): TRANDB(1)

OS 0.22 ONS
eS SOS OSS OO SB oS So OOo ae SEAWALLS) --------------- 3-5-5 cr crt rns H
H.1 ANY SEAWALL ALONG THE SIMULATED SHORELINE? (YES=1; NO=0): ISW

H.2 COMMENT: IF NO SEAWALL, CONTINUE TO I.
H.3 GRID CELL NUMBERS OF START AND END OF SEAWALL (ISWEND = -1 MEANS
ISWEND = N): ISWBEG, ISWEND

1 -1
[---- =~ = 95 22 eer ance ern BEACH EATIEIGS iaia\-\ ili toi i tle I
I.1 ANY BEACH FILLS DURING SIMULATION PERIOD? (NO=0, YES=1): IBF

I.2 COMMENT: IF NO BEACH FILLS, CONTINUE TO kK.
I.3 NUMBER OF BEACH FILLS DURING SIMULATION PERIOD: NBF

I.4 DATES OR TIME STEPS WHEN THE RESPECTIVE FILLS START
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501, NBF VALUES): BFDATS(T)

I.5 DATES OR TIME STEPS WHEN THE RESPECTIVE FILLS END
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501, NBF VALUES): BFDATE(1)

1.6 GRID CELL NUMBERS OF START OF RESPECTIVE FILLS (NBF VALUES): IBFS(T)
I.7 GRID CELL NUMBERS OF END OF RESPECTIVE FILLS (NBF VALUES): IBFE(T)

I.8 ADDED BERM WIDTHS AFTER ADJUSTMENT TO EQUILIBRIUM CONDITIONS
(NBF VALUES): YADD(1)

File START_VER representing the verified version of the START file. Only

lines that are different from those in START_CAL are shown.

oS sobs dauaasassaacesase MODEL SETUPS fee =e se aia aay S12] A

RUN TITLE

LAKEVIEW PARK CASE STUDY, MAY-JUNE 1989, VERIFICATION

DATE WHEN SHORELINE SIMULATION STARTS

(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501): SIMDATS

781009

DATE WHEN SHORELINE SIMULATION ENDS OR TOTAL NUMBER OF TIME STEPS
(DATE FORMAT YYMMDD: 1 MAY 1992 = 920501): SIMDATE

791117

oo Soe beget dae aes saaase WAVIES Stee eee eee ep

DATE WHEN WAVE FILE STARTS (FORMAT YYMMDD: 1 MAY 1992 = 920501): WDATS
780101

sidconsaede ass aaa eees IAL CROUNS /JETUURS emma ee ec ee ei ea

IF GROIN OR JETTY ON LEFT-HAND BOUNDARY, DISTANCE FROM SHORELINE
OUTSIDE GRID TO SEAWARD END OF GROIN OR JETTY: YG1
128

SHORL Files

File SHORL_771024 holding shoreline position 24 October 1977. DX = 25 ft.
KKK KAKI K IKK KH KKH KI EE TKK HK KK KK HHH HH

SHORL.DAT HOLDS SHORELINE POSITIONS. MUST CONTAIN NN VALUES.

EXACTLY 10 ENTRIES ON EACH LINE! LVP, 771024
Th ink ini ino ink ini inion rinbsienk hin kit

U5 2) MS AR2) S72 6220 e/ Si 2) UO GSR: 2a 27 2p Dito) ey Demme 22 Oey e212. O Re
DUBE 2. S212 2022 22 Om Din 2i OC 2aee 2A OT 2 el) 2s 2.6) sta 215) 52 N Ee
D5 ASS\a PUSS OUD 2Y AU TREE PUNE CUS 2LOScAQ CSU oL
Dee PSS POC VUS6 PUSS ASCE er aol Ws or, 228)3) 574) CoP
29725 2922 2872) w2BNEN2 A279) 2ee DiS) 2 e2i7Ale 2263) 02g 2 O22.

File SHORL_781009 holding shoreline position 9 October 1978. DX = 25 ft.
KKK AHH HAE HEHE HHH K HHI IKK K KKK HHA IEEE TE TE TE TE TE TE TE TE TE HE

SHORL.DAT HOLDS SHORELINE POSITIONS. MUST CONTAIN NN VALUES.

EXACTLY 10 ENTRIES ON EACH LINE! LVP, 781009

Sok inink oink oink iii iin ininik bininik hinbek bnkbkr
L3G O Ra UAB RGN IS Sean 684 SS 4 el Oily 420220 Sa ZO 8 a
207.4 208.4 209.4 213.4 217.4 216.4 219.4 227.4 238.4 249.4
ZONA S277 EG 2834" 2794) 275 e4 W272 NOM 2 Sy NDC 4e 2 Sinton ON Sie
DI DZELE 269R4E DORA © 27254) M271 W283 2RA e289 Gen 299 eee sO aes ZO:
325.4 318°4 307-4 301-4 296.4 29474) 285.4 2814) 127624

File SHORL_791117 holding shoreline position 17 November 1979. DX = 25 ft.
HEHEHE KAKA KKH AAA EEE HHH HAHAHA TE TE TE TEE DE EEE IEE ETE TE TE TE TE TE TE TE DEDEDE TE TE TE TE TE TE TE DE DE

SHORL.DAT HOLDS SHORELINE POSITIONS. MUST CONTAIN NN VALUES.

EXACTLY 10 ENTRIES ON EACH LINE! LVP, 791117
oR ok kk ie inininink inininink coiininink iii bine bibbikk

86.5 aS) ills sy Tilo es) lwo sy avs) alle sy Ace) MAS. O85)
202 5m 203e 5% 1205555 92047 De 205 a e2 oe ZO e229) ie 23 Beam 2-> ORD
MSs) Bilge PICS S0555) SOS6S: 2235) OSES) ZV2sS 2OGca | ZOD.)
Aas) | AOU soy Wee) Ales) USS) “ZEOcs) “Wpiee), Oik3cs) “SSWoo, SS.)
34525) S495 S49 Roi 33425025 OMS loom O47. an2 4 oR ZO oe

SEAWL File

File SEAWL holding seawall position. DX = 25 ft.
KKK KKK KAI K III III III IIIA IKI III II III III KIKI III III II IIIA IIIA KIKI

SEAWL.DAT HOLDS SEAWALL POSITIONS. MUST CONTAIN NN VALUES.

EXACTLY 10 ENTRIES ON EACH LINE! LAKEVIEW PARK. DX = 25 FT.

{RICK dodo oid: adie idk inne oink oieoininink biniiner
-84.0 -45.0 -39.0 -41.0 -41.9 -42.8 -43.7 -44.6 -45.5 -46.4
“4723 -48..2 1-490 (-49.°9) S-5088) =I V/A -S26n yO S10) n COA DOr
256.2 =S/iak -5870) “=587.9) 332720) 27) 0n 2710-27 JON maps Oe OO)
-68:0 -=63)7.0 -57.0 -53410) -50-0 )-4820) -47/10) -49.0)) 52205-5470
-57.0 -60.0 -62.0 -63.0 -120.5 -178.0 -180.0 -182.0 -184.0

WAVES File

File WAVES_LVP holding wave data for a representative year.

DT = 6 hrs.

KKK KH KH HK HH HK HHH KKH K HH K HHH HARK K KKH KH KH KH HK KKK KK KK KH KKK KKK KKK EKER ERE

WAVES FOR LAKEVIEW PARK. PRODUCED USING ITM 37,

SHADOWING FROM THE HARBOR & ICE FROM DECEMBER TO MARCH ACCOUNTED FOR.
KKKK KKH KKH KHKKK KAA KEK AKA KAKA HHH KH HK KKK KKK HHH KEK ARK KK KER

-0.00 0.00 0.00 JAN
-0.00 0.00 0.00
-0.00 0.00 0.00
-0.00 0.00 0.00

(wave data are given
in tabular form below)

-0.00 0.00 0.00

Wave data in wave file WAVES_LVP.DAT:

T H a T
-0.00 0.00 0.00 J 4.00 0O
-0.00 0.00 0.00 A 600K eT
0008 10:300 0.00 N 4.00 0O

4.00 0

: 8.00 3
(a total of 360 4.00 0
"zero" lines from 4.00 0O
Jan 1 to Mar 31) 8.00 2
400040

4.00 0O

-0.00 0.00 0.00 600U2
-0.00 0.00 0.00 4.00 0
-0.00 0.00 0.00 4.00 0
6.00 1.60 38.00 A 6x00}!
4.00 0.86 -10.00 P 4.00 0O
4.00 0.86 -10.00 R 4.00 0O
SOOM sa 9) 3.81400 6.00 1
4.00 0.86 -10.00 4.00 0
4.00 0.86 -10.00 4.00 0
GROOM 5) B15) 200 610002
4.00 0.86 -10.00 400950
4.00 0.86 -10.00 4.00 0O
6.00 1.93 -8.00 8.00 2
4.00 0.86 -10.00 400820
4.00 0.86 -10.00 4.00 0O
6.00 1.93 -8.00 8.00 2
4.00 0.86 -10.00 4.00 0O

PoPFOFPFNF FOP FOF OHFEFNF SF OHKE OF

SAVILLE, 1953.

FHrOPFAOFEFAFFWOHFFWOEFHF OFF OFF OFF OFF OFF OFF OPK KF OFF WOHKEHHE HEHEHE ADH

SCOFOOMOONDOWOONMOONDOF ODF ODWOOWOODOWOONTTOWOOWOOCOrFrDOFOCOFS

OFF OFFWDFEFHDFEFAHDFEAHDFHFUOF EHF EHDEFEHDFEAHDFEFHFEHDFHEAHFEHDFEHDFEADFEHA

NOVO TOTO TOL Oro Or OW OVOUWsOnO IW sOrO rN OyOh FO Os FOr Or ORO OLONOtO Or OO OrzOrOrO lOO Oreos

orFaroaorFFaFHFaPrFPFaoPoPrPEenFF OP FWOEFWOFHFOHFFNF KF ORWOEEAHAFEFHFEAFEOH

NOON OWOOWOOWOOWONOCOKFOONOCOFLFONOGCONOGOORPOONONOCONCGCCOOOCO OOF eo

FENFFFNF FFF DF FFU KF EHDFFEFHDFFHFHFHEHKHKHIF FORK OP FOF FUP LOOP Pore

SOLO F SOc Orin Ors Or Os OvOE OA ORs Ol Ore Ol sOlLOrO st" OnOrOrO | OL Or OO 1WiOrwO Wr Oro! Ox =O. O.1.O

2aq

Se OL i a oe a oD OEE oe ODE A So OLE EE a OE EE OE a Ee ODE RE od OLE Ne Se Se oe ro

OO NO OC:Oo oF OC oOF OOCOrFP COCO F OOCOOCOFOOOFRPOOOOFROOOFROOONOOOrROCOOOON oO

FFF FFF FUP HK HEHE HOHE HR OPK REFN RR OPK KEENE KR ORK LOPE ERAE

FFHFEFNFHFHF HF OPHKEFEFHDFFHFEFHDFHFHKFFENFKFKEHDEF HEHE EHF KK EFNKF KR EHDE KEE D

ORO 2O 1 OF VOsO 1S Or Or OPO u Oro Ont ORO OrOINVOrO Orr COLO Oromo Oo TOO OyNzOLrOnOrOrnOlOnr@ (Ole

FaOFFFFEFNF FFF OPK EFF EFNF FHF HF OHFKFHEF HSK OPEFE HEE HDFHK FEU HF HEENF KKK SEO

OBwBOOWOOOFOAOOODWOODOOOONOQCOOONGDOOOONOQGOOCOOFPOOCOCOOCOOOCOCOOFOCOOCO OC ON

FFF EFNFEHDEFHFEHDEFHEADFEHDHSHEHFHEULF EDF HEFHFOPEHDEFEFHEFEHDFHEUFHKHSIF REE

DODORFCONOGDOCOOFRFOCOOFRFOOFRFOCOOFRFOQOOrRFOQOOCOOOOrFRFOCONOOFOCOCOOoOoOOrFoCcoooor|ITSOCCSO

QAcPrY

COrEFADFFEFHDFEFNF FEOF FFE EEHDEF EHF HK EHDE EDF EERE EHDEFHFEHDSEKAHK HK PULSE

rPoonooc”crorcorocoooooo°0cocorcorecacorcaoreoacorecoOorcacaOoOrFCOrFCCOrRCSO

NEFF EFHDF FHF EHF EFHDFEFHDFEHDFHUSHKEIP RR OPENER EOE D HEHE ERE HLOHKHSE

FNFFOHKHFFNF EDF EDF EHF HF EHDEFEHDE FUP KEHEEHDEE HDF HK HKFOK KOREN EDEHE

SDFDWOODOWODONDOFDVOFOCORFAODOOFDVOORFP ADCO OFCOFPCORFPODONDOWOOFRFOCOFOO

FEFNFFHFHFHFUOF FEAF FOF OFF OFF FOF OFF OFF KF OFF OFF OFF OFFS DE LOL

Or WO O11 | OOO t || S2O Ww OO OVO WOOO iWrOrOsWrOiO OOO SSO OrNiS OW OS (Os Out 1S

FRE AFHFFNFHHKFHFEFUOF FFE HDFHFFEFDEFHFHFOHFHKHFFWOPEFHFFOPEKHEEHDEFEEHDEFHFHEHEDSE

S-O71O1R O10 OIW1O1O10 70 1H O19 12 INOS (O19 1" Ol Oe O45 110 IN (OC O11 tO 10S Ort" (O10 Ot 1910 10720 1.

oo ee ro ee eo Ee a ao a ee Se et tt a oe tt oe oe ee

SDFODODOOF OOO OWDDDOWDDDOONDODONDODONDOODOOFOODOOFRFODOODOOCOONDVOOCOON SO

oFrFFaOFFF OFF EF WOFHF EF EFNF FHF ORK KOR K ENF KK REDE EHDEHK EF HLUIP ER RENYNR RSE

WODONDADODNDAOONDWODONDOONDTDODOWODONDODOFDOADAONDIOOORPIOOCOOLFOCOO

FOF OFF EF DFFF ENF FHF KF OPS KN KR OPK KEK OK ROPE ROPER ROR E

FFF FOF FF OHFHKF FOP KF SF OKHK HL OHKHSE
oo
(2) )
OFS O1O OO. ON 9 O-O WO. © Wi OO WO: OO WO: Oo ©
[oe]
fon)
'
re
Oo
Oo
Oo

-0.00 00 =6—0.00
-0.00 00 860.00
-0.00 00 860.00

(a total of 120
"zero" lines from
Dec 1 to Dec 30)

-0.00 0.00

0.00
-0.00 0.00 0.00
-0.00 0.00 0.00

OUTPT Files

File OUTPT_CAL resulting from the calibration calculation:

RUN: LAKEVIEW PARK CASE STUDY,

INITIAL SHORELINE
LS 2a Sass Zee oii
218. Qi 2 2ak2
2:9)9)- 263/209 V2 352
255). DIE Pa PADS
AG DVO. OS

Nh NM NH
MM NHN PH

LAST TIME STEP. WAVES ORIGINATING FROM

BREAKING WAVE HEIGHT
ORS OFS 45 O}.29
0.05 0.04 0.03
0. 0. 0.

0. QO. 0.

0 0 0

BREAKING WAVE ANGLE TO X-AXIS

162.
210.
219%.
213%.
ZO.

SSS} (SS)

NO NM ND ND PO

.24

17S
210.
281.
DIS)
219

MPNMNMN NH

.19

SLOnOnOre@

Ts syb alle Ay Ass cI Ped oiens), 1 7X43 7/2)

7.83 Yoo Uses

0. QO. QO.
QO. 0. 0.
0. 0. 0.

LAST TIME STEP. WAVES

BREAKING WAVE HEIGHT

0.
0.
0.

ORIGINATING FROM ENERGY WINDOW NO.

0.
0.
0

OF 0553 0.53 OF53 OR3
0.54 0. 0. 0. 0.
0. 0. 0 0. 0.
0. 0. 0 OF 0.
0. 0. 0 0. 0.
BREAKING WAVE ANGLE TO X-AXIS
0. Ae 39 D2 2) loo 9
5.26 0. 0. 0. 0.
QO. 0. 0. 0. 0.
0. 0. 0. 0. 0.
0. 0 0 0. 0
LAST TIME STEP. WAVES ORIGINATING
BREAKING WAVE HEIGHT
0.09 Oe abil Oj (O) ls} OpalS
0.37 0.94 0.96 0.96 0.94
0.25 0.18 OFU4 0510S 0209
0.04 0.04 0 0. 0.
0. 0 0) 0. 0.

MAY-JUNE 1989, CALIBRATION

220.
2333)
263.
295.
252.

NM NHN Lh

UAC Pale, 725 72
PM So 7a PASo 75 CAPA oe
LASSI MAU es P2 ) PUB EO
PRS GAN PAINS, CE DOL
LU Seed PAU MP4 CASEI OC
ENERGY WINDOW
Ono OR E2S eS OR09
0. 0. 0.
0. 0. 0.
0. 0. 0.
0. 0. 0.
DO) «| DSARVZ AAG ON) DKS)5 XS)
0. 0. 0.
0. 0. 0.
0. 0. 0.
0. 0 0.

Se 'Crey eS)

SCRORSIKSTKS)

Isygenss lls) a 7474" | heey

0.
0.
0.

FROM ENERGY WINDOW NO.

0.16
0.89
0.07

D16

0.
0.
0.

CCCI)
oF
DO WO

0.
0.
0

oooow

220.2
244.2
257.2
295.2

ooon Sie Cy~e) Syoyeyxe) (S) Corey eS)

(Seo)

.06

.18

.50

foe
sols}
.04

BREAKING WAVE ANGLE TO X-AXIS

13/592

2.16
22 Oi)
OR alt
0.

LAST TIME STEP.

8.96
4.93
23) 16
Ze 2
0.

15.34
4.70

23.67
0.
0.

WAVES

BREAKING WAVE HEIGHT

1B! 77,
4.55
5.66
0.
0

ORIGINATING FROM ENERGY WINDOW NO.

19.63
4.46

-2.96
0.
0.

OF 0. 0. 0. OF
0. 0. 0. 0. 0.
0.24 0.24 0.24 0.24 £0.24
QO. 0. 0. 0. 0.
0. QO. Of 0. 0.
BREAKING WAVE ANGLE TO X-AXIS
0. 0. 0. 0. 0.
0. 0. 0. OF OF
14.49 14.17 13.11 12917 49
0. 0. 0. 0. 0.
QO. 0. 0. 0. 0.
LAST TIME STEP. WAVES ORIGINATING
BREAKING WAVE HEIGHT
0.06 0.06 0.06 0.06 0.06
0.08 0.08 0.09 O210) O11
0.21 0.24 0.28 0:34, OF43
1.03 PO 0.98 0.93 O53
ORFS O1209 0.07 0.06 0.05
BREAKING WAVE ANGLE TO X-AXIS
14.70 9255) L6R47 © 20.3 2144
“O78; -106 -1a7 -146" -1 04
15.13 14.76 13.41 -4.08 -10.56
eo OL 90) O21" 0.57 6.77
13.01 -1.31 -6.40 -9.64 -8.02

LAST TIME STEP.

WAVES ORIGINATING

BREAKING WAVE HEIGHT

Secor OrOre

(SOS) OTS)

Sy eyVeee{S)

SO) (SKS)

LOS Siar l6 sk2
4.46 4.37
Seis). Sikes
0: 0.
0. 0.

.24

SiO2O7O5o:

(SSS)
oa)
Ww

FROM ENERGY WINDOW NO.

SIONS ee)

D17

ocooooc°o

Oro CO ono

fe nevrene)

Seeman)

.24

S°O493079)

SRC S)

2 LOZ 2)

Cy eyi vere)
So
oO

=I.
I)

(SHS (SS}

pet
OOnWi©

(So) [ey S)

SS} Sy SIS)

.24

aly,

233

BREAKING WAVE ANGLE TO X-AXIS

0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
OZ 0. 0. 0. Seis 92326) LOS ON LORnOs Pe LOn43 Seo!
3290) 4207" 8 -7-.20) 936 0. 0. 0. 0. 0.

LAST TIME STEP. WAVES ORIGINATING FROM ENERGY WINDOW NO. 7

BREAKING WAVE HEIGHT
0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03
0.03 0504 O504 0204) O204 0.04) 0:04 0.04 OR04 10:04!
0.04 0204 OS04 O04" 0305 0305) 1OR05 0.06 0.06 0.07
0.08 0.08 0.09 0.10 0.11 OFZ Onda OFS 0.17 0.20
0.24 0.31 0239 0.50 0.93 1.00 1.05 1.08 1.10

BREAKING WAVE ANGLE TO X-AXIS
U5e85) ORGY Pl i6) 21s le 2299 Ol 22S OO es unle7 i509 9.96 3.09
0.58 08322) -O702 0.09 0.64 1.43 4.15 10.94 15.24 16.54
19/28) “19522 -18)05) ~=2)- 71) - 1 86) -15 863\" 10 N07, 105 0-9) 97 9 all
-7.96 -6.45 -4.50 -3.00 S10) A339) US On 2a Ss 6s Onl
3.06 -10.01 -13.23 -14.05 -8.71 -8.59 -8.48 -8.42 -8.38

GROSS TRANSPORT VOLUME (YARDS3) FOR CALCULATED PART OF YEAR 1
36310 45967 48287 49323 47485 44151 40880 35693 31864 30314
28894 28696 27242 24888 23349 21664 19094 17224 16488 16620
17086 17966 18560 17964 16192 15805 19627 20727 22050 22664
23225 23226 24940 25258 22169 21343 21325 21280 21442 20334
18728 16679 16973 17843 21430 22789 22271 22319 19340 1501

NET TRANSPORT VOLUME (YARDS3) FOR CALCULATED PART OF YEAR 1
4228 4780 5253 5570 5729 5850 6156 6621 6938 7226
7446 7576 7596 7511 7340 7122 6893 6648 6495 6297
6130 5961 5725 5480 5354 5348 5525 5647 5694 5573
5361 5135 4967 4924 5078 5253 5420 5557 5490 5203
4727 4193 3604 3012 2429 1924 1411 976 480 -154

TRANSPORT VOLUME TO THE LEFT (YARDS3) FOR CALCULATED PART OF YEAR 1
-16040 -20592 -21516 -21876 -20877 -19149 -17368 -14436 -12461 -11543
-10724 -10559 -9822 -8689 -8001 -7271 -6098 -5287 -4996 -5161
-5478 -6002 -6417 -6241 -5419 -5228 -7051 -7540 -8178 -8544
-8933 -9045 -9986 -10166 -8545 -8044 -7952 -7861 -7975 -7565
-7000 -6243 -6684 -7415 -9500 -10432 -10429 -10670 -9429 -828

TRANSPORT VOLUME TO THE RIGHT (YARDS3) FOR CALCULATED PART OF YEAR 1
20269 25373 26770 27446 26607 25001 23510 21253 19400 18768
T8169 ~18136) 17419 16199) 15348) 14393) 12995) 1936 7 IaI4925 11458
11608 11964 12144 11722 10773 10577 12576 13187 13872 14119
14293 14180 14953 15090 13623 13298 13373 13419 13466 12768
11727 10438 10288 10427 11929 12356 11841 11648 9910 673

D18

OUTPUT OF BREAKING WAVE STATISTICS FOR SELECTED LOCATIONS
N.B. WAVE DIFFRACTION IS NOT ACCOUNTED FOR!

GRID CELL NUMBERS

PRPePrPP

PRP PR
rFOrFCO

ONDFN

(FT3/SEC)

e277,
357

.059

.005
.002
.007
.002
.009

CIN sea:

il 2 3 4 5 6 7
Lat 12 13 14 a5 16 17
all 22 23 24 25 26 27
Sl 32 33, 34 35 36 37
4l 42 43 44 45 46 47
AVERAGE UNDIFFRACTED BREAKING WAVE HEIGHT
1.0 1.0 1.0 1.0 1.0 10 1.0
1.0 1.0 10 1.0 1.0 10 1:0
0 ESO sO 1.0 add ed ib odk
ial ial, Ikea 0 110 1.0 10
ital Tioal ikeal bell ileal iepal bea
AVERAGE UNDIFFRACTED BREAKING WAVE ANGLE TO SHORELINE
-5.7 -4.4 -7.4 -8.7 -9.6 -10.4 =O) -7.
Diehl: 2.4 Drv ILA 0.4 -1.2 ie, -7.
lls} o 8) ils} A7/ leon lakeal -2.0 GAO alee (yell
eat 1.0 -1.6 =259 -6.7 = Sree he s—s022
-8.2 -0.3 U6 9.4 4.5 Show) 30 at
AVERAGE LONGSHORE TRANSPORT RATE WITHOUT DIFFRACTION
-0.034 -0.033 -0.064 -0.077 -0.087 -0.102 -0.089 -0
0.075 0.088 0.086 0.077 0.054 0.031 -0.009 -0
ORAS - O50) -O SEI. O[009% O8130> O8179' O2142) O)-
0.072 0.053 0.016 -0.006 -0.047 -0.090 -0.107 -O.
SORO74" SO8038> O37" O62) O13 Otol “O7084 0
LONGSHORE TRANSPORT (FT3/SEC)
0. -0.002 -0.004 -0.005 -0.006 -0.006 -0.005 -0
0.000 0.001 0.001 0.001 0.000 -0.002 -0.003 -0
-0.01 -0.001 -0.002 -0.001 -0.001 0.000 0.005 O
0.04 0.002 -0.002 -0.003 -0.003 -0.003 -0.002 -0
-0.02 0.000 0.000 0.001 0.006 0.009 0.010 0O
CALCULATED SHORELINE
P2654 329° Wes Om MoS 0K 167.8 2180 an ois) | 201:
Deere Ssie216 0) E29 220022209) 226% 209923'3
AOD) BUS o3 ALE PAV) hikes) HUGos AVSoU eZ
26Dmae) 2647105 26510 26653) 2704 2797 289)10) 298
S 2A SUB ens PSGt) SOUR 63 O19 296.2 = 290F7 285
CALCULATED SEAWARDMOST SHORELINE POSITION
SL eS. Wel SOR Se 2 S23 6n3) 2 27al6n 2173,
BU 8) DEN ts BOR e DRS BRB c72 PRG) PSY sy 7xhAL
2YO 0) Ass 2I3se> SOS AOodl esos 2/972 “Z27/s)
ZOD ZO Gd 2OVin Ie 27Si2) 2192 287 25 295.20) 3 Oi
SAG SoZ S266) S20) ,0l SLOn a 13035298.) 295)

D19

NM CON C

.042 -0.
055

-0.
0.
-0.

017
085
117
146

045

.003
.001
.007
.002
.006

fo oF Nf aly)

DrFwowmn

PPP PR

(ey (ea)

“See ~!

ANN SES

mS OWWM

CALCULATED LANDWARDMOST SHORELINE POSITION

919" LO6:
206.0) 207.
253/60) (263):
24102) 243%
29697 129.2%

CALCULATED REPRESENTATIVE

wonun fl

122.6
208.4
DY IAS S)
247.4
287.2

139.
207.
27:9%
243.
281.

aio a Gy ae yy ware 7) lakes)

DBO Smo Se 2: a0 0R5s 205%.
123955 124306 L247 — 1 269"
1258.7 1260.3 1262.3 1264.
1283.0 1283.4 1282.9 1281.

95 2.
2 208
22s
te} 250)
2) 278

OFFSHORE
.8 1146

6 1210
9 1251
7) L267
6 1278

CALIBRATION/VERIFICATION ERROR =

32)
jal
ay
58)
4

oe)
.6
ge)
ap)
33

NO aS). cl.
2a 2a =
271.1 264.
209758 1 (271s:
DAU Sys 3b WXs7/-¢

CONTOUR

1155.9 1163
1215.6 1220
1253.5 1254
1270.6 1273
Ay Se i Bay fa

4.03645

D20

FrNNND

ts} Dney/al
ty b225)
ny 255
OMA Qik
.6 1268

186.
214.
258.
284.
261.

NWO COUN

pak MULT &
yor 2308
26) L256"
50) I27/2)..
13 265%

195.
224.
2511).
295.
25/2).

NONE AO

Loe
231°
247.
295.

1184.
123.5%
1257.
1281.

NOW hN

CoM FF

File OUTPT_VER resulting from the verification calculation (Year 1 refers to
the period 9 Oct 1978 through 8 Oct 1979, Year 2 refers to the period 9 Oct

1979 till the end of the simulation period):

RUN: LAKEVIEW PARK CASE STUDY, MAY-JUNE 1989, VERIFICATION
INITIAL SHORELINE

131.4 139.4 148.4 158.4 168.4 183.4 191.4 202.4 208.4 208.4
20754 20824 ©2094 21334 (217.4 21634 219).4 3227.4 .238.4. 249.4
ZOGSA. 21s 2835s 279. ae 2754) ) 22a 21345 218). 4-5 275).4 , 2I3).4
Dideas 2694) (270.45) 272.4) (277-4) (2824, 2894) 129974 31054 320.4
325.4 318.4 307.4 301.4 296.4 294.4 285.4 281.4 276.4

GROSS TRANSPORT VOLUME (YARDS3) FOR CALCULATED PART OF YEAR 1
21131 44696 54797 59264 61894 60843 58831 54605 48872 45301
42159 40481 38028 34870 31417 28324 25605 21766 20514 20193
21028 22150 22910 22744 21335 21105 27188 28573 29633 30039
30478 30148 32153 32072 28076 26760 26519 26352 26282 24090
21536 19155 20025 22020 28047 29819 29210 29023 29061 4254

NET TRANSPORT VOLUME (YARDS3) FOR CALCULATED PART OF YEAR 1
-1540 -563 444 1441 2373 3190 3987 4643 5244 5709
6036 6235 6370 6445 6528 6618 6600 6559 6529 6532
6542 6614 6698 6635 6404 6174 5979 5846 5871 5872
5862 5853 5785 5728 5689 5643 5517 SeVILY/ 5100 4893
4707 =4527 4241 3826 3437 3061 2769 2402 2063 1719

TRANSPORT VOLUME TO THE LEFT (YARDS3) FOR CALCULATED PART OF YEAR 1
-11335 -22629 -27175 -28911 -29759 -28826 -27422 -24981 -21813 -19795
-18061 -17123 -15828 -14213 -12439 -10852 -9502 -7600 -6992 -6829
-7243 -7768 -8106 -8054 -7465 -7464 -10604 -11361 -11882 -12083
-12308 -12146 -13184 -13172 -11194 -10557 -10500 -10517 -10591 -9598
-8414 -7313 -7891 -9096 -12304 -13378 -13219 -13308 -13493 -1267

TRANSPORT VOLUME TO THE RIGHT (YARDS3) FOR CALCULATED PART OF YEAR 1
9795 22066 27620 30353 32133 32016 31409 29622 27055 25501
24096 23357 22199 20657 18976 17471 16102 14165 13522 13363
13785 14381 14804 14689 13869 13639 16584 17210 17752 17956
18170 18000 18968 18899 16881 16202 16019 15835 15691 14491
13120 11841 12133 12923 15742 16440 15990 15714 15566 2987

D21

LAST TIME STEP.

BREAKING WAVE HEIGHT

0.99 0.38 On34.5 0829 0.24
0.06 0.05 OF04 fF ORO4 sO;
0. QO. 0. 0. 0.
0. 0. 0. 0. 0.
QO. 0. QO. 0. 0.
BREAKING WAVE ANGLE TO X-AXIS
14.24 Pars. WAS Sik PAL sey. Ay Ges
6.25 7.10 6.42 Yeon 0.
0. 0. 0. 0. 0.
QO. QO. 0. 0. 0.
QO. 0 0. 0. 0.
LAST TIME STEP. WAVES ORIGINATING
BREAKING WAVE HEIGHT
0. 0.56 0.56 0.56 0.56
0.58 0. 0. OF 0.
OF 0. 0. 0. 0.
0. QO. 0. 0. 0.
0. 0. QO. 0. 0.
BREAKING WAVE ANGLE TO X-AXIS
0. U2645 5 TAG LE 920, M858
7.88 0. 0. 0. 0.
O. 0. 0. 0. 0.
0. 0. 0. 0. 0.
0. 0. 0 0. 0
LAST TIME STEP. WAVES ORIGINATING
BREAKING WAVE HEIGHT
0.11 OR ORSIAS ORES 0.17
0.38 0.99 1.02 103 PO!
0.28 0.20 0.15 OAR OR09
0.05 0.04 0.04 0.03 0.
0. QO. 0. 0. 0.
BREAKING WAVE ANGLE TO X-AXIS
IVS Ais) Al Sa 96) 227189.
0.66 8.99 8.69 8.47 8.30
D5 MASe 2866s 287.25) oleae OM Dee
-2.46 0.61 5.05) ORGS 0.
0: 0. 0. 0. 0.

31.06
0.

QO.
0.
0.

FROM ENERGY WINDOW NO.

LOMA
0.

0.
0.
0.

FROM ENERGY WINDOW NO.

Sl)
197,
.08

SrO Orr

D22

ooo°co

WAVES ORIGINATING FROM ENERGY WINDOW NO.

elt.

Holy 7 327265 32

0.
0.
0

phlei SILT 5 NS Lys

OF
0.
0

S50 O Ou.

102

0.
0.
0.

SOLO. OSES:

0.
0.
0.

SSeS)

.14
oath

0.
0.
0

SeVyere)

SOrOLOLOr©)

S,9O' OC: O70

Seley Cre)

. 86
0.

eid
ae,

eye yey{— ooo°o

ooo°o

Syteouicy )

.07

.58

.30

LAST TIME STEP.

WAVES ORIGINATING FROM ENERGY WINDOW NO. 4

BREAKING WAVE HEIGHT

0. 0. 0.
0. 0. 0.
0226 0826 0.26
0. OF 0.
0. 0. 0.
BREAKING WAVE ANGLE TO X-AXIS
0. 0. 0.
0. 0. 0.
6E83) Wei 1589
0. 0. 0.
0. 0. 0.

LAST TIME STEP.

0. 0 0. 0.
0. 0 0.26 0.26
0.27 0 0. 0.
0. 0 0. 0.
0. 0 0. 0.
0. 0. 0. 0.
0. QO. 14.50 15.42
-11.59 0. 0. 0.
0. 0. 0. 0.
0. 0. 0. 0.

WAVES ORIGINATING FROM ENERGY WINDOW NO. 5

BREAKING WAVE HEIGHT

0.07 0.07
0.09 0.09
0.22 0.25
1.14 legally
0.11 0.08
BREAKING WAVE
18.52 4.66
-2.88 -2.09
18.07 19.61
-1.45 -0.44
2is2on 1285

LAST TIME STEP.

WAVES ORIGINATING

BREAKING WAVE HEIGHT

CS) CVS) CVS)

BREAKING WAVE ANGLE TO X-AXIS
0

cooo°d

SS) (SV eye) (S)

Sy)

CS) Sieve yiS)

0.
0.
OF
-3.

ooo0oc°o

0.08 0.08
0.10 0.11
OF29" ) Ols35
1.08 1.02
0.06 0.06
ANGLE TO X-AXIS
11.79 19.06
-2.82 -1.80
Ly e372 0.66
OR 2.20
1.31 -20.76

0.
0.
0.
0

25 -14.21

(SOS (SS)

SSS) te) (eS)

0.08 0.08 0.08 £0.08
Ons) Oras O16 OS
OTT OAIG 1.05 1.11
OF49e OR S9 TF Oe30F (0):2a
0.05 0.04 0.04 0.04

FROM ENERGY WINDOW NO. 6

OF 0. 0. 0.
QO. 0. QO. 0.
0. 0. 0. 0.
O64 O36 0236 | 0236
QO. 0. 0. 0.
0. 0. 0. 0.
0. 0. 0. 0.
0. 0. 0. 0.
11.78 14.07 14.94 14.57
0. 0. 0. 0.

D23

oooc°o

ra
oon oO

iS)

(>) (SSS)

NOOO

. 26

162

. 36

237

LAST TIME STEP. WAVES ORIGINATING FROM ENERGY WINDOW NO. 7

BREAKING WAVE HEIGHT

0.04 0.04 0.04 0.04 0.04
0.04 0.04 0.04 0.04 0.04
0.05 0.05 O5059) 205055 O05
0.09 OO9F ORO; MOS 2s TORS
O5.23)) OR29) NOe38) Osa 1.02

BREAKING WAVE ANGLE TO X-AXIS
1:9)7'89 De, USS) 2016527 26036
= 61 -O)9/0)) =1h338i 8 = 0)3211! 2's
D269) 2455831, 227.99 3.41 -12.08

-11.65 -8.67 -4.41 100%) 1325
10.60 1.95 -7/274) = 23°04) -10).70

GROSS TRANSPORT VOLUME (YARDS3) FOR CALCULATED PART OF YEAR 2

4840 12749 12402 15443 17352
8875 8667 8191 7630 7159
5363 5533 5344 5148 4766
5891 6100 7276 7359 6255
4698 4343 4332 4341 4895

NET TRANSPORT VOLUME (YARDS3) FOR CALCULATED PART OF YEAR 2

3343 3431 3566 3735 3929
4300 4176 4102 4082 £4101
3601 3397) 3153 2898 2644
2423 2612 2826 3037 3206
2932 2646 2207, 1699 1293

TRANSPORT VOLUME TO THE LEFT (YARDS3) FOR CALCULATED PART OF YEAR 2

-748 -4658 -4417 -5854 -6711
-2286 -2245 -2044 -1774 -1528
-881 -1068 -1095 -1124 -1060
=17/ 345) 17/43 22225-2160) -V524
-883 -848 -1057 -1320 -1800

TRANSPORT VOLUME TO THE RIGHT (YARDS3) FOR

4092 8090 7984 9589 10640
6589 6422 6146 5856 5630
4482 4465 4248 4023 3705
4157 4356 5051 5198s 473
3815 3494 3275 3020 3094

0.04 0.04 0.04 0.04 £0.04
0.04 0.05 £40.05 0.05 0.05
0.05 0.06 0.06 0.07 0.08
On4S 0.157 OL 6y On as 0.20
ae ae aii Gags Ue) ee) 1.21
29 Oy 12802) 280958 Loan 2693.6
8EOSty VOL64) W625 2) i873 2k 58
= 2L949.9) FATE a O) 147-93 Ol = NS ay// 20 e103) 48.9)
14.37 18.42 20.06 19.70 16.62
-10.27 -10.22 -10.22 -10.22
15912 14307 14700 12777 9941
6720 6307 5651 5320 5186
4335 5060 5185 5354 S579
6262 6488 6476 6418 5628
4758 4267 4442 4225 423
4128 4306 4442 4518 4505
4134 4127 4058 3939 3789
2376 2228 2166 2187 LEU T
3283 3328 3325 3260 3128
969 722 548 443 389
-5891 -5000 -5129 -4129 -2718
-1293 -1090 -795 -691 -698
-979 -1416 -1509 -1583 -1651
-1489 -1580 -1575 -1578 -1250
-1894 -1772 -1946 -1890 -16
CALCULATED PART OF YEAR 2
10020 9307 9571 8648 7223
5427 5217 4855 4629 4488
3356 3644 3675 3771! 3928
4773 4908 4900 4839 4378
2863 2494 2495 2334 406

D24

OUTPUT OF BREAKING WAVE STATISTICS FOR SELECTED LOCATIONS

N.B. WAVE DIFFRACTION IS NOT ACCOUNTED FOR!

GRID CELL NUMBERS

PRP PR
NNNNND

MMM DN NH

7
6
oY) Sj:
9
2

(oe ol li |

(FT3/SEC)

117 -0.064
051 -0.095
173 10 aUGi
184 -0.197

1089) 00517

.009 -0.010
.004 -0.002
JOZDeMORO2Z5
.003 -0.003
.030 0.020

WrwWr Oo
i)
~N
bh
WADAWOrF

1 2 3 4 5 6 7
11 12 KS} 14 15 16 7,
21 22. 23 24 25 26 27,
Si 32 33 34 35 36 37,
41 42 43 44 45 46 47
AVERAGE UNDIFFRACTED BREAKING WAVE HEIGHT
2 a2 12 1B a2 lee 12
lee 2 152 Te? 12. M2 Wed 2
2 IL ee Ly2 2 loo 72 2 12
il: 12 2 il? 1 2 Nee Not
12 Wee lhe ae 2 es Lee
AVERAGE UNDIFFRACTED BREAKING WAVE ANGLE TO SHORELINE
-6.9 35)5 8) -6.4 = O04 VOSS eis.) IMS. =O.
-0.1 Lee Peel 1a OD Sill sal -2.4 = Vic
SIL S Sy) DulsyaGy | alls iees) -3.4 6.3 13353 655 5
2.6 iho) -1.3 -2.9 =7.9) OLS) a2 2) a
-8.4 OZ Sid 2 Dia 4.5 356
AVERAGE LONGSHORE TRANSPORT RATE WITHOUT DIFFRACTION
-0.051 -0.035 -0.060 -0.091 -0.106 -0.126 -0.135 -O.
OOS WOLOSie 0 LID ORO 0082 04052. 0.023" -0'.
-0.184 -0.196 -0.162 0.003 0.168 0.240 0.188 O.
0.105 0.078 0.034 -0.002 -0.057 -0.109 -0.136 -O.
SOROIMRORO64S 2 ON17 85 (052225 05159 OF 14a (0.122% 10
LONGSHORE TRANSPORT (FT3/SEC)
0.0 0.001 -0.002 -0.005 -0.007 -0.008 -0.009 -0
0.003 0.012 0.014 0.011 0.003 -0.009 -0.012 -0
-0.002 -0.002 -0.002 -0.002 -0.001 0.002 0.020 0O
0.017 0.010 -0.001 -0.012 -0.006 -0.004 -0.003 -0
-0.003 -0.002 -0.001 0.003 0.022 0.028 0.031 0O
CALCULATED SHORELINE
83/45 88.0 TsO MOVs) Was US USS} Le
20220 oom 20669) 208) Sie2e Oe 2 eo 22438 234%,
DOs eZ BAe Ded SOM 2a ZOU Vie 2 SiO LO Derlam 2iG)-
2643) ZO Onm 2OSIs46 2OOhOF a AGO 286-15 5298..5), Sil2-
SANS) Sh) S\aLO BIS) SVAN) SS) SYS GAD SAT AE) SULA SOE) E7/ esOL
CALCULATED SEAWARDMOST SHORELINE POSITION
WAM. IL Wes IL IL oe), Wesel ICY oy Asi Sil
ZU 23S Ved Ome 226non 228500 259) 235840 2aae
DY Br19) W294 Ie SO 89) weSilele 3 23 06n49 — 295n 1 e287 51 Zen).
AUS 58) AYES) BU Coik Ao. Asses, “Aesi oo) shoysS) | Shiloh,
Spills) Seto, isi Seeoa Bye 7 —syAlaG Silsyoloy Shile

D25

oO ONMNO
iw)
~N
~N
FOnO

Pee Re

NM NM ND bh

OA Or

NW wo

Nun oO

CALCULATED LANDWARDMOST SHORELINE POSITION

22D 31.0 30.6 33%
VOM E SOG 2 LO Ge Sy O87:
Wes \eUe ADT SS) AT oe Pele
244.6 247.4 248.8 247.
31908 S167) B30754) 1299"

FO
200.6
275.4
25 D109
29356

FaArWN

CALCULATED REPRESENTATIVE OFFSHORE
1067.8 1079.1) 1090.5 1101.8 1113.1
P7228) WUC 27 SoZ eo ee 20487,
12GG 6. 12497 253825702592
U264—3 12661 2687) U27 20.2 27/6" 3
153 Ole 3 O28) 213 O27 m3 Ole 329687,

CALIBRATION/VERIFICATION ERROR =

Ae Ora o es
208/25) 2.3"
224269):
266.8 280.
2877/6) 2.8/1

CONTOUR

ase) ae aye
WA 7 i dL Zane) 6
1260.5 1261.
1281.1 1286.
L292 1287.

4.06798

D26

NOMNW SO

136.
216.
264.
295%.
276.

1145
1226
1261
1291
1283

ONOoOFwo

.2 1154
ao) 232
.8 1262
ml e295

LOME2ZT Ee

AYE
224.
25.0%.
308.
268.

WwOnrewN
i)
nn
(o>)

moO NO CO

NrPOF

APPENDIX E: NOTATION

This appendix contains separate lists for mathematical notation and the
names of variables in the computer program that appear in the input START file
and elsewhere. Length units are given as meters (m), but "feet" (ft) may be

substituted if American customary units are selected in the modeling.

Mathematical Notation

a, Longshore sand transport parameter (contains K,; see below)
ag Longshore sand transport parameter (contains K,; see below)
1/3

Bottom profile shape parameter, m
Subscript denoting condition at wave breaking

Bie Composite of variables in the double-sweep algorithm (sec/m’)
Wave phase speed, m/sec

Wave group speed, m/sec

Cop Wave group speed at breaking, m/sec

D Water depth, m

ds Median sand grain size, mm

Dy, Water depth at wave breaking, m

Dp Average berm height, m

De Depth of closure, m

De Water depth at groin tip, m

Dit Depth of active longshore transport, m

Dito Maximum depth of longshore transport, m

E, Double sweep recurrence coefficient

F Total fraction of sand passing over, around, or through a shore-
connected structure (groin or jetty)

F; Double sweep recurrence coefficient, m?/sec

g Acceleration due to gravity, m/sec?

H Wave height, m

H, Breaking wave height at arbitrary point "Point 2," m

H, Deepwater wave height, m

H, Breaking wave height, m

Breaking wave height without diffraction, m

Wave height at the reference depth, m

Wave height at reference line, m

Subscript denoting grid cell number; also, arbitrary counter
Longshore transport rate calibration parameter; also Kl
Longshore transport rate calibration parameter; also K2
Diffraction coefficient for combined wave diffraction
Diffraction coefficient for diffracting source on left
Diffraction coefficient for diffracting source on right
Wave diffraction coefficient for a transmissive structure
Refraction coefficient

Shoaling coefficient

Wave transmission coefficient for a single structure
Wavelength, m

Wavelength at breakpoint, m

Wavelength in deep water, m

Number of independent wave components

Number of calculation grid cells; also NN

Sediment porosity

Cross-shore sand transport rate, m?/sec/m

Cross-shore sand transport rate from offshore, m?/sec/m
Cross-shore sand transport rate from the shore, m?/sec/m
Longshore sand transport rate, m/sec

Gross longshore sand transport rate, m?/sec

Longshore sand transport rate at a groin, m*/sec
Longshore sand transport to the left, m°/sec

Net longshore sand transport rate, m°/sec

Longshore sand transport to the right, m*/sec

Ratio of smaller valued to larger valued transmission coefficients
Stability parameter

Time, sec

Wave period, sec

Mean longshore current speed, m/sec

Longshore coordinate, m

Width of surf zone, m

Shoreline position, m

Shoreline position difference, m

Length of groin on left side of cell 1, m

Length of groin on right side of cell N, m

Width of littoral zone, m

Added shoreline width of a beach fill, m
Difference in calculated and measured shoreline positions, m
Average nearshore bottom slope, deg

Wave breaking proportionality constant

Calculation scheme stability coefficient, m?/sec
Calculation scheme stability coefficient, m/sec
Calculation scheme stability coefficient, m2/sec
Angle of wave crest to depth contour, deg

Mean value of sinusoidally varying wave angle, deg

Angle of wave ray started at Point 1 that will reach a given location
(Point 2), deg

Angle of wave crests to x-axis, deg

Angle of wave crests to the shoreline, deg

Angle used to determine the value of the diffraction coefficient, deg
Angle defined by Points 1 and 2 used to approximate angle 6,, deg
Angle of shoreline to x-axis, deg

Density of water, kg/m?

Density of sediment, kg/m®

Change in longshore sand transport rate, m?/sec

Time step, sec

Change in volume of small beach section, m®
Grid spacing alongshore, m

Change in shoreline position, m

Prime; denotes new time level

ABH
BFDATE
BFDATS
BYP
DDB
DDG

D50
DCLOS
DLTZ
DT
DIW
DX

IDG
INDG
IPRINT
IRWN

Program Variable Names

Average berm height (also, D,), m

Array holding ending dates of beach fills

Array holding starting dates of beach fills

Groin bypassing factor

Array holding depths at tips of detached breakwaters, m

Array holding depths at seaward ends of diffracting groins and
jetties, m

Median grain size, mm

Depth of closure (also, D,), m

Maximum depth of longshore sand transport (also, D,7o), m
Time step, hr

Time increment in the WAVES data file, hr

Longshore cell length, m

Depth of offshore wave input, m

Wave height, m

Wave height change factor; a factor that can be applied to increase
or decrease the input wave height

As the first letter of a variable, denotes that the variable is an
integer or an array of integers

Toggle denoting existence of beach fills; no (0), yes (1)
Array holding grid cell numbers of end (right side) of beach fills
Array holding grid cell numbers of start (left side) of beach fills

Toggle specifying a conversion factor for whether metric (1) or
American customary length units (2) will be input

Toggle denoting existence of detached breakwaters; no (0), yes (1)
Toggle denoting existence of a detached breakwater crossing the left
boundary; no (0), yes (1)

Toggle denoting existence of a detached breakwater crossing the
right boundary; no (0), yes (1)

Toggle denoting existence of diffracting groins; no (0), yes (1)
Toggle denoting existence of nondiffracting groins; no (0), yes (1)
Toggle turning the time step display off (0) and on (1)

Toggle turning repeated warning messages on (1) and off (0)

ISMOOTH

ISBW

ISPW
ISW
ISWBEG
ISWEND
IXDB
IXDG
IXNDG
IZH

PERM
SIMDATE
SIMDATS
SLOPE2
STAB
TOUT
TRANDB

Number of calculation cells included in smoothing the shoreline to
define the shape of a representative offshore contour

Number of shoreline calculation cells per wave model element (valid
only if an external wave model was used, NWD = 1)

Number of shoreline calculation cells per wave model element
Toggle denoting existence of a seawall; no (0), yes (1)
Beginning grid cell number of the seawall

Ending grid cell number of the seawall

Array holding grid cell locations of detached breakwaters
Array holding grid cell numbers of diffracting groins

Array holding grid cell numbers of nondiffracting groins
Integer variable holding compressed wave data

Longshore transport rate calibration parameter for oblique wave
incidence

Longshore transport rate calibration parameter for longshore
gradient in wave height

Number of beach fills during the simulation period
Number of detached breakwaters

Number of diffracting groins

Number of calculation grid cells

Number of nondiffracting groins

Number of intermediate outputs (not including that from the last
time step, which is a default output)

Toggle specifying whether an external wave model was used to provide
a nearshore wave data input file; no (0), yes (1)

Number of wave components per time step

Array of groin permeability coefficients (empirical)

Ending date of the simulation

Starting date of the simulation

Representative bottom slope near groins

Stability parameter

Array holding dates or time steps of intermediate printouts

Array holding transmission coefficients of detached breakwaters
(empirical)

Starting date of WAVES file

Longshore coordinate, m

YADD

ZCNGF

Shoreline position, m

Added shoreline width of a beach fill after adjustment of fill to
equilibrium, m

Array holding distances of detached breakwater tips measured from
the x-axis, m

Difference

in calculated and measured shoreline positions, m

Length of groin on left side of cell 1, m

Length of groin on right side of cell N, m

Width of littoral zone, m

Array holding lengths of nondiffracting groins, measured from the

X-axis, m
Asi a firsit

Wave angle
be applied
deg

Wave angle

letter, denotes an angle

change amount; an angle (positive or negative) that can
to shift all input wave angles by the specified amount,

change factor; a factor that can be applied to the input

wave angle which acts to increase or decrease the wave angle range
(compress or expand the wave rose)

Beach change models
analytical model, 21
fully 3-D model, 23
profile erosion model, 22
schematic 3-D model, 23
shoreline change model, 22
Beach fill
added distance for, 91
as direct shoreline change, 54
representation of, 90, 146
Beach profile shape
discussion of, 56
equation for, 56
equilibrium shape, 56
Beach profile shape,
width of littoral zone, 57
Berm elevation
in shoreline change equation, 50
Boundary conditions
default, 99
equations for,
gated, 42, 100
general discussion of, 41
pinned beach, 42, 87, 101
Breaker index
equation for, 65
Bypassing
discussion of, 88
equation for, 89
Calibration
definition of, 44
Coastal experience
advantages and disadvantages, 15
and calibration procedure, 44
Contour modification
discussion of, 69
DEPTH file
discussion of, 126
Depth of closure
determination of, 57
for Oarai Beach, 57
for Oceanside Beach, 57
in shoreline change equation, 50
Lakeview Park, 156
predictive equation for, 61
Depth of longshore transport
discussion of, 54
equation for, 55
maximum, 55
Detached breakwaters
parameters describing, 142
Diffraction
diffraction coefficient, 67
multiple, 80
Error messages
discussion of, 136
External wave transformation model
calculation procedure, 74

86, 87

GENESIS
acronym for, 9
basic assumptions of, 48
boundary conditions, 86
capabilities and limitations, 20
cautions, 13
coordinate system and grid for,
design mode, 32
external wave model, 61
general structure of, 97
history of, 11
input data, 33
Input files for, 102
internal wave model, 61
number of structures in, 139

APPENDIX F:

INDEX

numerical solution scheme of, 81
output files for, 129
sand transport calculation
domains, 77
scoping mode, 32
theory of, 47
wave energy windows, 77
Groins
complex configurations of, 143
legal representation of, 143
Input data
list of, 36
minimum requirements, 34
Internal wave transformation model
calculation procedure, 62
Lakeview Park
as case study, 149
calibration and verification for,
166
five-year simulation for, 175
location map, 150
model sensitivity tests, 169
transport rate coefficients for,
170
WAVES file for, 161
Line sources and sinks
in shoreline change equation, 50
uses of, 54
Longshore sand transport rate
effective threshold for, 94
empirical predictive equation,
52
gross, 93
in shoreline change equation, 50
multiple wave sources for, 92
net, 93
practical considerations of, 91
transport rate coefficients, 52
Numerical solution
diffusion (heat) equation, 82
discussion of, 81
equations for implicit scheme,
86
explicit scheme, 83
grid system for, 84
implicit scheme, 84
numerical and physical accuracy,
81
stability parameter for, 83
Oarai Beach, 17
depth of closure of, 57
shoreline change at, 18
Oceanside Beach
depth of closure of, 57
OUTPT file
discussion of, 129, 132
Planning process
and shoreline change models, 25
comprehensive planning, 25
five general issues in, 28
role of shoreline change
modeling, 29
single-project planning, 25
RCPWAVE
acronym for, 74
Representative offshore contour
discussion of, 73
Sand bypassing
at groins and jetties, 54
discussion of, 88
equation for, 89
Sand transmission
discussion of, 88

permeability factor for, 89
Sand transport calculation domains
definition of, 77
examples of, 78
Seawall
discussion of, 90
representation of,
SEAWL file
discussion of, 125
example of, 126
Sensitivity testing
definition of, 45
SETUP file
example of, 132
SHORC file
discussion of, 136
Shoreline change
governing equation of, 50
Shoreline change model
duration of simulation, 17
history, 16
role in planning process, 29
spatial extent, 19
SHORL file
discussion of, 123
example of, 123
SHORM file
discussion of, 124
example of, 125
Snell’s law
equation for, 65
Stability parameter
equation for, 83
START file
general discussion, 104
lines in, 104
Structures
detached breakwaters, 142
general effects of, 138
groins, 143
illegal positioning, 141
legal positioning, 140
permissible number of, 139
representation of, 138
rules for placement, 139
seawalls, 145
time-varying configurations, 148
Transmission coefficient
for transmissive detached breakwaters,
72
properties of, 71
Transport rate coefficients
as model transport parameters, 53
definition of, 52
empirical values of, 53
for Lakeview Park, 170
Variability in coastal processes
problem of, 42
Verification
definition of, 44
Warning messages
discussion of, 136
Wave angle
definition of, 65
Wave breaking
under combined transformations, 67
Wave calculation
angle, 65
breaker index, 65
breaking wave height, 67
depth-limited breaking, 65
external wave model (RCPWAVE), 74
external wave model, 61
general discussion of, 61
internal wave model 61, 62
limiting wave steepness, 76
multiple diffraction, 80

90, 145

representative offshore contour
73
Snell’s law, 65
transmission, 71
Wave energy windows
discussion of, 77
examples of, 78
Wave transmission
for Lakeview Park breakwaters,
171
transmission coefficient, 71
WAVES file
discussion of, 126
for Lakeview Park, 161
with nearshore wave data, 130
without nearshore wave data, 130

f
a
"
¥
fi
i
‘
'
:
a
at
; ees
: an
'
: 4
i
fi
fl
i‘
i ‘
1
1

¢
}
1
Wes.
*
ah

‘
4
i
6
uipe
i
a4
mY

ipa

as anit
. ee i

(isp iii
Lie.

—@) eipaee

aRie ® wa

Hoek.

Pau reer

aba Oe

DEPARTMENT OF THE ARMY

WATERWAYS EXPERIMENT STATION, CORPS OF ENGINEERS
P.O. BOX 631
VICKSBURG, MISSISSIPPI 39180-0631

SPECIAL FOURTH CLASS RATE
POSTAGE & FEES PAID
Department of the Army

Permit No. G-5

——EEESS
Official Business
Penalty for Private Use, $300
CEWES-IM-TS-T

37919/12/01

MARINE BIOLOGICAL LABORATORY

LIBRARY

WOODS HO-E MA 02543-1098

Internet Archive Audio

Featured

Top

Images

Featured

Top

Software

Featured

Top

Books

Featured

Top

Video

Featured

Top

Mobile Apps

Browser Extensions

Archive-It Subscription

Save Page Now

Full text of "Genesis: Generalized model for simulating shoreline change, report 1, technical reference"

See other formats