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Biological Services Program

FWS/OBS-80/09
June 1980

W H 0 I

DOCUMENT

COLLECTION

GRAVEL REMOVAL

GUIDELINES MANUAL

FOR ARCTIC AND

SUBARCTIC FLOODPLAINS

Interagency Energy-Environment Research and Developnnent Program
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
and

Fish and Wildlife Service

U.S. Department of the Interior

The Biological Services Program was established within
the U.S. Fish and Wildlife Service to supply scientific informa-
tion and methodologies on key environmental issues that im-
pact fish and wildlife resources and their supporting
ecosystems.

Projects have been initiated in the following areas: coal
extraction and conversion; power plants; mineral development;
water resource analysis, including stream alterations and
western water allocation; coastal ecosystems and Outer Con-
tinental Shelf development; National Wetland Inventory;
habitat classification and evaluation; inventory and data
management systems; and information management.

The Biological Services Program consists of the Office of
Biological Services in Washington, D.C., which is responsible
for overall planning and management; National Teams, which
provide the Program's central scientific and technical exper-
tise and arrange for development of information and
technology by contracting with States, universities, consulting
firms, and others; Regional Teams, which provide local exper-
tise and are an important link between the National Teams and
the problems at the operating level; and staff at certain Fish
and Wildlife Service research facilities, who conduct in-house
research studies.

FWS/OBS-80/09
June 1980

GRAVEL REMOVAL GUIDELINES MANUAL
FOR ARCTIC AND SUBARCTIC FLOODPLAINS

U.S. FISH AND WILDLIFE SERVICE

by
Woodward Clyde Consultants

4791 Business Park Blvd., Suite 1 , Anchorage, Alaska 99503
Principal Authors

M.R.Joyce

LA. Rundquist

L.L. Moulton

With Input From
R.W. Firth, Jr.
E.H. Follmann

Contract Number

FWS-1 4-1 6-0008-970

This study was funded

in part by the

Interagency Energy-Environment

Research and Development Program

Office of Research and Development

U.S. Environmental Protection Agency

Performed for the

Water Resources Analysis Project

Office of Biological Services

U.S. Department of the Interior

Washington, DC 20240

DISCLAIMER

The opinions, findings, conclusions,
or recommendations expressed in this
report are those of the authors and
do not reflect the views of the Office
of Biological Services, Fish and Wild-
life Service or the Office of Research
and Development, U.S. Environmental
Protection Agency.

INTRODUCTION

A study was initiated in mid-1975 to evaluate the effects of gravel
removal from arctic and subarctic floodplains in Alaska. The primary purpose
of the project was to provide an information base to assist resource man-
agers in formulating recommendations that would minimize detrimental environ-
mental effects of gravel removal from floodplain material sites. To achieve
this objective 25 material sites were studied by a team of scientists and
engineers. Three major products resulted from the study. They are: (I) a
Technical Report presenting synthesis and evaluation of the data collected
at the sites, (2) a Guidelines Manual that aids the user in developing plans
and operating material sites to minimize environmental effects, and (3) a
Data Base filed with the U. S. Fish and Wildlife Service in Anchorage con-
taining raw and reduced data, aerial and ground photographs, and other
relevant material from each site. This report is the Guidelines Manual.

APPLICABILITY OF THE GUIDELINES

It is important to recognize that the guidelines contained in this
manual were developed from a study of 25 floodplain material sites in arctic
and subarctic Alaska. Therefore, they deal neither generally nor specifi-
cally with material sites in upland or coastal situations. Similarly, they
do not include evaluation of the relative acceptability of utilizing an
existing active or abandoned material site or an abandoned structure contain-
ing gravel (such as a drill pad or airstrip) rather than a floodplain site.
This should not be interpreted as recommending sites in floodplains over
other locations. WHEN A NEED FOR GRAVEL HAS BEEN IDENTIFIED, ALL ALTERNA-
TIVES SHOULD BE CONSIDERED. ONLY AFTER A FLOODPLAIN HAS BEEN SELECTED FOR
THE PROPOSED MATERIAL SITE DO THE GUIDELINES CONTAINED HEREIN BECOME APPLI-
CABLE . However, if used cautiously some guidelines may be utilized in other
site and regional situations.

The 25 material sites exhibited a range of variation in site age,
gravel mining method and location; and river configuration, origin, and
size. Selected sites were minimally affected by complicating factors such as

nearby bridges, culverts, villages, and other material sites. The latter
case is significant in the application of these guidelines. On large proj-
ects it is sometimes necessary to locate a series of material sites in close
proximity along the floodplain of a river. The effects of multiple material
sites in a floodplain were not evaluated in this study. Hence the appli-
cation of these guidelines to multiple site projects must recognize this
shor tcomi ng .

The user should be thoroughly familiar with the contents of the Techni-
cal Report to give perspective to the guidelines for their effective use.
THE GUIDELINES ARE DESIGNED TO DIRECT THE PROCESS OF IDENTIFYING, PLANNING,
PREPARING, OPERATING, AND CLOSING MATERIAL SITES; THEY ARE NOT MEANT TO BE
USED AS STIPULATIONS TO BE USED IN EACH AND EVERY CASE.

It is essential that the user of these guidelines consider each materi-
al site individually. Identification of unique characteristics may require
that certain guidelines be ignored or interpreted differently, or different
combinations of guidelines be considered. This manual is intended for use by
all individuals interested in floodplain gravel removal.

GRAVEL REMOVAL METHODS AND CLASSIFICATION

A variety of gravel removal methods and river characteristics are
covered by this manual. In general, these methods and river characteristics
consi st of :

1. Scraping exposed or vegetated gravel from active and inactive flood-
plain and terrace deposits. Scraping usually does not involve work-
ing in active channels.

2. Pit excavation of vegetated gravel deposits located in inactive
floodplains and terraces.

3. Dredging from the bed of active channels of large and medium-sized
r i vers.

SUMMARY OF PROJECT RESULTS AND CONCLUSIONS

Study of 25 floodplain material sites has shown that disturbance result-
ing from gravel removal operations can be minimized. Two gravel mining tech-
niques were used at the study sites, scraping of surface or near-surface
deposits and pit excavation of deep deposits.

In general, approaches to minimize environmental changes caused by
scraping included maintaining buffers between active channels and the work
area and avoi ding:

• Instream work

• Mining to depths and in locations that induce permanent channel
shifts or ponding of water

• Clearing of riparian vegetation

• Disturbance to natural banks

Large rivers and braided rivers generally provide the most accessible
gravels for scraping. Gravel mining using scraping technqiues in these areas
frequently resulted in the least environmental changes.

Pit excavations resulted in permanent loss of terrestrial riparian habi-
tat, however, many pits increased local habitat diversity. These newly
created habitats frequently received concentrated utilization by local
fauna, particularly fish, waterfowl, shorebirds, and furbearers. Large
quantities of material were excavated using pit mining techniques. Pits that
were located on the inactive side of the floodplain, and were separated by
vegetated buffers in the range of 50 to 100 m, generally did not influence
active channel hydraulics.

Pits were found to be most beneficial to local fauna when they exhib-
ited the following characteristics:

• 2 ha or more in size

• Contained diverse shoreline configuration

• Contained diverse water depths

• Contai ned i elands

• Contained an outlet connected to active channels

PROCEDURES FOR GUIDELINE USE

To use this manual it is necessary to acquire information on site loca-
tion, operation, and environmental conditions. The information consists of
descriptions of the site and gravel removal methods that will allow predic-
tion of floodplain changes.

The manual is divided into seven sections based primarily on the order in
which a site will be selected, reviewed, and worked (Figure I). Although site
selection is the primary topic of Section I, much of the information in the
other sections is also valuable in selecting appropriate mining locations
and methods. For this reason, the entire manual should be read and clearly
understood before deciding on a final work plan. For example, much of the
information in Section VI - SITE OPERATION can be valuable in determining
where selection of a specific method or location may increase the amount of
available material while decreasing environmental alteration.

After the guidelines have been thoroughly reviewed, it is recommended the
sequence presented below should be followed.

SITE APPL I CANT

1. Identify suitable sites using the procedures described in Section I.

2. Develop a tentative plan on how and where to remove the required
gravel within the proposed site. Acquire field data needed to complete
Site Planning as described in Section II.

3. Evaluate the proposed plan by applying the appropriate guidelines from
the SITE PREPARATION, SITE OPERATION, and SITE CLOSURE Sections. This
may identify alternative methods or locations and potential problems,
speed the review process, and lead to more efficient site operation.

4. Develop a formal Work Plan, as described in Section III, to be sub-
mitted to the appropriate agency.

Problem

Geiwfal S<t<
SdKtion

MATERIAL NEED

Coastal

Upland

Floodplain

Active or Abandoned
Gravel Source

Floodplain
Gravel
Removal

Guidelines
Manual

IDENTIFICATION OF SUITABLE SITES

Section I

Decision 1

Technical Characteristics

reject

Decision 2

Significant Environmental Features

reject

Decision 3

Technical/Economic Criteria

reject

Decision 4

Other Environmental Criteria

reiect

eject

SITE PLANNING

Section II

WORK PLAN DEVELOPMENT

Section III

AGENCY REVIEW

Section IV

4
I
I

1
I I

I Agency Site i

I Vicitt I

submit

Applicant Site
Reconnaissance

' Applicant Field I

approval

Visits

SITE PREPARATION

Section V

SITE OPERATION

Section VI

SITE CLOSURE

Section VII

I Inspection '
I . ^1

Figure I. Gravel mining planning and implementation.

5. Work and close the site in accordance with the appropriate guidelines
and approved Work Plan.

SITE REVIEWER

1. After receiving a work plan completed in accordance with Sections

I through III, evaluate the plan and site location for the presence of
significant environmental features identified in Section IV.

2. Visit the site to evaluate the technical feasibility, proposed bounda-
ries, habitat quality, and possible environmental concerns.

3. Use Sections V through VI I to evaluate the Work Plan and suggest
modifications, if appropriate.

4. Following approval, conduct site visits during operation and closure
to check adherence to the approved Work Plan.

Gravel Removal
Guidelines

Identification of Suitable Sites
Section I

Page

GENERAL GUIDELINES II

SPECIFIC GUIDELINES M

Technical Characteristics of

Alternative Sites 12

Areas or Species of Special

Concern '2

Technical and Economic Criteria . . 13

Other Environmental Criteria ... 14

VERIFICATION OF SITE ACCEPTABILITY ... \b

Identification of Suitable Sites
Section I

A. GENERAL GUIDELINES

A number of factors influence the suitability of a gravel removal site.
Among these are:

• Technical Requirements - such as quantity and quality of available
material, required processing (washing of fines)

• Economics - such as hauling distance, and site preparation and
rehabilitation requirements (overburden removal, river-training
structures, and site grading)

• Environmental Characteristics - including location within the flood-
plain, and biological characteristics of the site

Many projects require more than one type of material, and these types
often will not be available from a single material site. Linear projects
such as pipelines and roads will require sites spaced along their
length. In regions where winter construction activities are required,
stockpiling of gravel in summer may be necessary to provide material
with lower moisture content.

B. SPECIFIC GUIDELINES

Because of the need to incorporate technical, economic, and environ-
mental factors, siting decisions must be considered on a case-by-case
basis. However, a sequence of four levels of decisions should be util-
ized in site selection. All levels should consider both previously undis-
turbed sites as well as previously mined sites. There may be occasions

11 I. IDENTIFICATION OF SUITABLE SITES

when previously mined sites are more suitable because of the presence of
access roads, airstrips, removed overburden, and existing unused stock-
piled mater i a I .

A preliminary site visit is appropriate to provide input to the follow-
i ng dec i s i ons.

1. Decision I - Technical Characteristics of Alternative Sites

Two initial steps are important in the site identification process.

a. Determine that the area can provide material meeting the
technical and volumetric requirements of the project. These
requirements must be obtainable within suitable buffers (refer
to buffer recommendations in Section V A 3 and Appendix A).

b. Determine if more than one specific site that meets these
requirements exists in the area

Failure to determine availability of suitable material can result
in unnecessary economic cost and environmental damage if initial
mining activities show a site to be unsuitable. It is desirable to
identify alternative sites in an area of interest because not all
sites will be acceptable.

2. Decision 2 - Areas or Species of Special Concern

The alternative sites identified in Decision I should be evaluated
relative to their disturbance of the features listed below. A site
affecting these areas should be modified, or in some cases dis-
carded, to minimize or eliminate any effect.

a. Threatened or endangered species and their habitats that are
deemed essential to the survival or recovery of these species
that are recognized by Federal and State governments. A cur-
rent listing of species and information as to their distri-

12 I. IDENTIFICATION OF SUITABLE SITES

bution may be obtained from the U. S. Fish and Wildlife
Service or the State Fish and Game agency. Sites affecting
these species or their habitats may be prohibited, or require
substantial justification.

b. Habitats limiting local populations (such as fish spawning and
overwintering habitats, Dal I sheep lambing areas or raptor
nesting habitats). Sites directly affecting these habitats
should not be considered further unless alternate sites are
not ava i I ab I e.

c. Undercut vegetated banks and associared riparian zones

d. Incised vegetated banks and associated riparian zones, except
for properly utilized access by fill ramps

e. Spr i ngs

f. Active channels in sma I I rivers of meandering, sinuous, and
straight configurations

g. Wetlands - The primary criteria most frequently used in wet-
land definitions include presence of water-saturated soil con-
ditions, and vegetative communities adapted to such con-
ditions. For current definition, delineation and jurisdiction
refer to local offices of the U. S. Army Corps of Engineers.

h. Other Federal, State, and private lands with special use and
regulation such as wilderness areas, parks, wildlife refuges,
archaeological areas, and historical landmarks

3. Dec I s i on 5 - Technical and Economic Criteria

Following the determination that suitable material can be obtained
from one or more sites without disturbance to areas or species

I. IDENTIFICATION OF SUITABLE SITES

of special concern, strong emphasis should be placed on selecting
an economical site. Factors influencing this decision include:

a. Amount of site preparation and rehabilitation required. For
instance, it is desirable to minimize:

• Haul distance to project site

• Vegetation and overburden removal

• River-training structures and bank protection devices

• Length of access route

• Crossing of active drainage or channels

b. Matching site operational requirements to available equipment

c. Ability to work the site in a dry condition

4. Dec i s i on 4 - Other Environmental Criteria

If at this point two or more sites are suitable, then the following
environmental factors should be considered in final site selection:

a. Minimize disturbance to fish and wildlife habitats. For ex-
ample, if sufficient gravel deposits are available elsewhere,
active or high-water channels and vegetated habitats should be
avoi ded.

b. Minimize disturbance to local visual and scenic quality. For
example, locate sites in areas away from public view or where
they will be least visible; insofar as possible select loca-
tions that wi I I al low one to preserve the character of the
area.

I. IDENTIFICATION OF SUITABLE SITES

c. Bed load replenishment rate should be considered in site selec-
tion if the life span of the site is to cover several consec-
utive years, even if there will be inactive periods. Glacial
and mountain origin rivers, particularly near headwaters, have
potentially higher replenishment rates than rivers originating
in foothills or coastal plains.

d. Projects requiring large gravel quantities (roughly 50,000 m
or more), should consider the following:

• Scraping of unvegetated, mid-channel bars and lateral bars
in braided rivers, and medium and large split channel
rivers. This recommendation should be followed as long as
suitable buffers (see Section V A 3 and Appendix A) can be
ma i nta i ned,

• Pit excavation in terraces or inactive floodplains, as long
as sufficient buffer is maintained between the pit and the
act i ve f I oodp lain

e. Projects requiring less than 50,000 m should consider:

• Scraping unvegetated mid-channel and lateral bars in braided
rivers and large and medium split channel rivers; this recom-
mendation should be followed as long as suitable buffers can
be ma i nta i ned

• Scraping point bars of large and medium meandering rivers

• Scraping in terraces or inactive floodplains

C. VERIFICATION OF SITE ACCEPTABILITY

Before proceeding with SITE PLANNING, review the selected site on the
basis of the entire Guidelines Manual. Give special attention to the

I. IDENTIFICATION OF SUITABLE SITES

SITE PREPARATION and SITE OPERATION sections. The matrix tables within
SITE OPERATION specifically present recommendations about gravel deposit
type and location, and mining method.

The purpose of this verification review is to minimize decision-making
delays resulting from failure to consider site specific features.

'^ I. IDENTIFICATION OF SUITABLE SITES

Site Planning
Section II

Page

GENERAL GUIDELINES 18

SPECIFIC GUIDELINES 22

Scraping 22

Pit Excavation 22

Dredging 23

Site Planning
Section II

Site planning should incorporate the SITE PREPARATION, SITE OPERATION,
and SITE CLOSURE guidelines presented in Sections V, VI, and VII.

A. GENERAL GUIDELINES

1. If the technical method of gravel removal has not been determined
during site selection, then either scraping, pit excavation, dredg-
ing or a combination can be chosen by reviewing the SITE OPERATION
gu i de I i nes

2. Design of the specific work area boundaries should incorporate
the following factors:

a. Site configurations should avoid use of long straight lines
and be shaped to blend with physical features and surroundings
(Figure 2) :

• Scraping point bars of meandering and sinuous systems to
maintain slopes and contours resembling those of the natural
bars

• Scraping mid-channel and lateral bars of braided systems,
to maintain natural gravel bar shapes

• Excavating pits to provide irregular shorelines with curved
configurations, islands, spits, and diverse shoreline depths

b. Vegetated areas should not be disturbed when sufficient quanti-
ties of gravel can be obtained within prescribed buffers in
unvegetated areas of floodplains (buffers guidelines are in
Section V A 3 and Appendix A)

II. SITE PLANNING
18

c. When vegetated areas cannot be avoided, it is usually desir-
able to locate material sites in large stands of homogeneous
mature vegetated areas

d. The site should be located on the same side of the floodplain
as the material use point. This will minimize the need for
crossing of active channels.

3. All work scheduling should attempt to avoid conflicts with sensi-
tive biological events and extreme hydrological events.

Figure 2. Examples of desirable material site
locations and configurations.

a. In general, work should be scheduled to avoid peak biological
events, such as local fish migration and spawning, and bird
and mammal breeding, nesting, and rear i ng-of-young. For ex-
ample, site clearing of vegetation should occur in fall to
avoid the sensitive spring and early summer avian nesting
season. Occasions may occur when gravel removal operations
should be suspended to avoid disturbance to an essential
b io I og i ca I event .

II. SITE PLANNING

b. Where site work is occurring in the active or inactive flood-
plain, scheduling should allow for work suspension and removal
of equipment, materials, and stockpiles from the floodplain
during spring breakup or other predictable flood events

4. After incorporating the conclusions from the four levels of deci-
sions from Section I into a final site selection, a site investi-
gation (described in Appendix B) should be conducted to:

a. Verify that the candidate site can produce the quantity and
quality of desired gravel

b. Collect hydraulic measurements such as discharge, channel
cross sections, and bed material size distribution whenever
possible to assess the hydraulic conditions of the natural
channel (see Appendix B).

c. Determine the presence or absence of limiting fish and wild-
life habitat within the project site. Analysis should be based
on annual biological requirements (i.e., fish spawning and
overwintering habitat).

d. Flag site boundaries and buffer locations in preparation for
an agency site inspection. Flagging should be highly visible,
of weather resistant material, and maintained through site
operation and closure.

• Mark site boundaries on mature trees in timbered areas with
some highly visible material (such as paint or cloth
mater i a I ) .

• For flagging in the open-water season use l-m metal stakes
or rods driven approximately 0.5 m into the ground with

a red flag of approximately 15 x 15 cm attached

II. SITE PLANNING

• At sites to be opened during winter, all work area locations
(such as active channels, buffer locations, vegetated areas,
and gravel deposits) should be surveyed from reference points
established during the initial open-water site visit (Figure
3). Reference points should be selected so they can be found
in heavy snow cover during future site preparation. Establish-
ment of these surveys will reduce accidental damage to active
channels and buffer zones.

Do a summer travers
or stadia survey to,
locate material site/
boundaries

Material site
boundary

-Three or more temporary
bench marks which can
be located during winter

Figure 3. Schematic diagram showing recommended survey at sites
which are to be opened during winter.

5. If winter active-channel mining is contemplated, an additional site
visit should be conducted during winter. This visit is to determine
the presence of water at or downstream from the proposed site.

II. SITE PLANNING

B. SPECIFIC GUIDELINES

Specific site planning should proceed based upon the selected gravel
removal method.

I. Scraping in Active and Inactive Floodplains:

a. Material sites should be mined to ensure that after the ma-
terial is removed, sufficient gravel remains to maintain the
low-flow channel configuration (refer to Section VI B 2)

b. Since it is most efficient to work scraped sites in a dry
condition, the average depth of the groundwater table during
the desired period of mining and the effective use of river-
training structures should be assessed (refer to Appendix C on
river-training structures)

2. Pit Excavation in Inactive Floodplains and Terraces:

a. Pits should be considered when a large amount of gravel
(>50,000 m ) is required from a river that does not have large
exposed gravel deposits. If scraping is conducted in a situ-
ation where more gravel is required than is accessible within
the guidelines for scraping, overmining may result with corres-
ponding habitat and channel alterations. In these cases, it is
preferable to go to inactive floodplains or terraces and exca-
vate a deep pit (refer to Appendix D on pit design).

b. Pits should be located in areas where they will have a low
probability of diverting channels into the mined area. This
means they should be located on terraces, inactive floodplains,
or stable islands with the recommended buffer. Terraces are
preferred because of the reduced probability of channel diver-
sion.

II. SITE PLANNING

c. It is usually desirable to locate the pit within a dominant,
homogeneous mature vegetative community. This location will
reduce the chance that a terrestrial habitat of limited avail-
ability will be affected and will generally increase habitat

d i vers i t y .

d. It should be decided during site planning whether or not the
pit is to be connected to the river following the mining opera-
t i on

• A pit outlet provides an avenue of escape for fish that
become trapped in the pit during high water. A connected
pit, if properly designed, can provide fish rearing and
overwintering and increase the availability of sport fish.
Conditions necessary to provide suitable fish habitat in-
clude a diversity of depths with an average depth that mini-
mizes the probability of winter mortality.

• An unconnected pit has the potential to trap fish during
high water. If the pit is adequately protected from flooding
with a buffer of suitable height, and if the pit is not to
be managed for fish the creation of overwintering habitat is
not necessary and the average depth is not critical. A diver-
sity of water depths is desirable to create adequate water-
fowl and shorebird habitat.

3. Dredging in Active Channels of Large and Medium Rivers

a. Dredging in active channels of large and medium rivers should
be considered only if suitable floodplain sites are unavail-
able outside the active channel. In this situation, nonflood-
plain sources also should be evaluated.

b. Sites located in active channels should consider the following:

II. SITE PLANNING

i) Essential aquatic habitat in and downstream from the
site

ii) Unimpeded instream migrations

iii) Maintenance of natural pool:riffle ratio; riffles should
be avoided except in the following situations:

• In a long riffle, excavation may be acceptable near
the middle of the riffle

• When more rapid site recovery is desirable

• When the riffle is unproductive aquatic habitat be-
cause of cementation or infiltration by f i ne °sed iments

• Where deepening the thalweg may reduce or eliminate
auf e i s development

II. SITE PLANNING

Work Plan Development
Section III

Page
Maps, Sketches, Photographs .... 26

Legal Description 26

Site Description 27

Environmental Description 28

Work Plan Development
Section III

Detailed work plans should be prepared and submitted as part of the applica-
tion to the appropriate review agency. Work plans should include detailed
sketches, ground photographs, topographic maps, and if available, aerial
photographs showing:

• Accurate site boundaries

• Individual sequential work areas and boundaries

• Buffer locations and boundaries for both individual work areas and
the total site

• Locations of all floodplain temporary and permanent structures planned
for site operation and closure (e.g., access roads, river-training struc-
tures, bank protection devices, stockpiles, washing and processing struc-
tures, and overburden piles)

• Locations of gravel-use points (such as access roads, airstrips, and
camp pads)

Visual resource classification maps, if available from State or Federal agen-
cies, of the region surrounding the work site, should also be submitted. Spe-
cific sections of the work plan should present written descriptions that
address the following topics.

A. A brief legal project description identifying:

I. Names and addresses of applicant and major contractors, if known

III. WORK PLAN DEVELOPMENT
26

2. Intended material use, location of material use, and anticipated
life of the project utilizing the material

3. Life of the material site

4. Ownership of material site and adjacent lands
B. A technical site description identifying:

1. Size and specific location of all individual and cumulative work
areas

2. Season, duration, and frequency of all site work by individual work
area

3. Buffer locations, dimensions, type of vegetation, and soil
descr i pt i on

4. Methods, schedules, and locations for vegetative and overburden
clearing, temporary storage and handling, and permanent disposal

5. Quantity, type, and use of material to be removed from each work
area

6. Method of gravel removal' in each work area, including type and
number of equipment and identification of each material handling
step to be performed within the material site (i.e., collection,
stockpiling, sorting, washing, processing, transporting). Locations
and operation of each handling step should also be identified.
Washing operation descriptions should identify silt control proce-
dures and processing operations should identify use and storage
locations of materials such as solid waste and cement-processing
addi t i ves.

7. Cross-sectional configuration and location of progressive working
elevations by season or major project scheduling periods. For

III. WORK PLAN DEVELOPMENT
27

example, if the site is to be worked over several years, ttie de-
signed profile and configuration during each spring breakup and low
summer flow should be identified. Final working profile and config-
uration and site closure profile and configuration should also be
i dent i f i ed.

8. Specific locations, specifications, material composition, and con-
struction method of access roads, river-training structures, and
silt control structures.

9. Site closure (rehabilitation) methods and procedures including loca-
tions and specifications of permanent structures (such as overburden
piles). At pit sites consideration should be given to whether access
should remain after site closure. This decision influences the
design life of the access road.

10. Descriptions of logistical support and material transportation

methods, general routes, and frequency to and from the material site

C. An environmental description of the project area identifying:

1. Known biological resources of the general vicinity, including fish-
ery resources of the subject river system

2. Timing of major fish and wildlife history events and presence of
limiting habitat occurring in the vicinity of the material site

5. Hydraulic characteristics (such as channel configuration and dis-
charges) in the vicinity of the material site

D. The approved work plan should be considered an integral part of the
project by both the permittee and the permitting and monitoring agencies

III. WORK PLAN DEVELOPMENT

Agency Review
Section IV

Page

Disapproval Basis 30

First Field Inspection 31

Second Field Inspection 31

Third Field Inspection 32

Agency Review
Section IV

A. The proposed material site location and accompanying work plan should
be reviewed by appropriate agencies to evaluate the compatibility of the
project with the environment. This review should consider disapproval
or modification of the work plan if the material site directly affects
areas or species of special concern. Examples of such areas or species
i nc I ude :

1. Threatened or endangered species and their habitats that are deemed
essential to the survival or recovery of these species that are
recognized by Federal and State governments. A current listing of
species and information as to their distribution may be obtained
from the U.S. Fish and Wildlife Service or the State Fish and Game
agency. Sites affecting these species or their habitats may be
prohibited, or require substantial justification.

2. Habitats limiting local populations (such as fish spawning and
overwintering habitats, Da I I sheep lambing areas or raptor nesting
habitats). Sites directly affecting these habitats should not be
considered further unless alternate sites are not available.

3. Undercut vegetated banks and associated riparian zones

4. Incised vegetated banks and associated riparian zones, except for
properly utilized access by fill ramps

5. Springs

^° IV. AGENCY REVIEW

6. Active channels in small rivers of meandering, sinuous, and straight
conf i gurat i ons

7. Wetlands - The primary criteria most frequently used in wetland
definitions include presence of water-saturated soil conditions, and
vegetative communities adapted to such conditions. For current
definition, delineation and jurisdiction refer to local offices of
the U.S. Army Corps of Engineers,

8. Other Federal, State, and private lands with special use and regula-
tion such as wilderness areas, parks, wildlife refuges, archaeolog-
ical areas, and historical landmarks

B. A field inspection of the proposed site by the appropriate agency should
take place prior to site approval. A field inspection as described in
Appendix B should occur during an open-water season and include an evalu-
ation of :

1. Overall technical feasibility of project as detailed in the work
p I an

2. Over all quality of fish and wildlife habitat to be disturbed

3. Presence of any previously unknown features identified in Section
IV-A

4. Hydraulic characteristics such as discharge and stage in the vicin-
ity of the material site

Alternative sites should be requested of the applicant if it is judged in
this review that the material site will alter areas or species of special
concern to the point that population survival is affected.

C. A second inspection by the appropriate agency should occur during site
operation to:

IV. AGENCY REVIEW

1. Confirm that the work plan is being followed

2. Determine if unexpected biological, hydraulic, or engineering char-
acteristics warrant a deviation from the original work plan

D. A third field inspection by the appropriate agency should occur in the
latter stages of site closure prior to site abandonment and removal of
essential site closure equipment to ensure:

1. Final slopes, contours, and configurations of the work area comply
with the intent of the work plan

2. All additional site closure work has been performed and the site
will be abandoned, within practical limits, as close to original
conditions as possible

Additional visits after closure may be appropriate (i.e., to monitor erosion
con tro I ) .

IV. AGENCY REVIEW

Site Preparation
Section V

Page

GENERAL GUIDELINES 34

Verify Boundaries 34

Access 54

Buffers 35

Dikes 40

Vegetation Clearing 42

Vegetation/Overburden Handling . . 42

Settling Ponds 44

SPECIFIC GUIDELINES FOR SCRAPED SITES. . 44

Site Preparation
Section V

A. GENERAL GUIDELINES

1. At sites opened during winter all work area boundaries established
during the initial site visit (such as active channels, buffer loca-
tions, vegetated areas, gravel deposits) should be verified to avoid
accidental damage to active channels, buffer zones, and vegetated
banks

2. Design of floodplain access should incorporate the following factors;

a. Minimize access through vegetated habitats

b. If necessary to traverse vegetated areas:

• During winter do not remove the organic layer and do not
cover the access route with gravel; use ice roads to avoid
compaction of organic layers

• During summer do not remove the organic layer, but protect
from mechanical ripping and tearing by covering with gravel

c. Floodplain access should occur at the inside of a meander to
avoid trafficing incised banks at outside meanders

d. Avoid crossing other incised floodplain banks

e. When a bank crossing is required it should be protected with
a gravel fill ramp

f. Avoid crossing active channels

54 V. SITE PREPARATION

g. When required, active channels should be crossed via temporary
bridges, low-water crossings, or properly cul verted access road.
Refer to Appendix E on fish passage.

h. Floodplain travel to and from the work area should occur only
on designated access roads

3. Buffers are areas of undisturbed ground surface that are designed to
maintain the integrity of active channels. In general, low- flow or
flood-flow buffers are recommended at a site. Low-flow buffers are
recommended for scraping operations on unvegetated gravel bars adja-
cent to active channels. Flood -flow buffers should be used for scrap-
ing or pit-mining operations that are separated from active channels.
Operators of gravel removal activities may desire to use buffers wider
or higher than those recommended in order to protect the site from
inundation while it is being worked, since water levels at the time of
ining may exceed those for which the buffer is designed.

mi I

a. The low-flow buffer is a strip of undisturbed ground surface

extending up the bank and beneath the water surface from the low
summer flow water's edge (Figure 4). Its purposes are:

• To maintain the integrity of the channel configuration and

• To minimize change to the aquatic habitat

The boundaries of the low-flow buffer are defined as follows
(F i gure 5) :

i) The upper limit at any location along the channel is that
point on the bank that is the lesser of the following:

• having an elevation that is 0.5 m above the low summer
flow water surface elevation

35 V. SITE PREPARATION

Figure 4. Schematic diagram of the low-flow buffer.

0.5W

'_ _ JihannelFuJI §\?9? y

0.5m

Low Summer Flow Stage

O.IWl

0.5m
_ow- Flow Buffer

Figure 5. Schematic diagram showing low-flow buffer boundaries,

• having a horizontal distance to the low sunnier flow
water's edge which is equal to one-half the channel
top width at channel-full flow conditions

ii) The lower limit at any location along the channel is that
point on the bed that has a horizontal distance to the
water's edge which is 10 percent of the top width of the
low summer flow channel.

b. The flood- flow buffer is a zone of usually undisturbed flood-
plain, often vegetated, separating the material site from the
active channel (s) (Figure 6). Its purpose is to prevent the

Figure 6. Schematic diagram of the flood-flow buffer.

V. SITE PREPARATION

active channel(s) from diverting through the material site for
a selected period of time. Although it is preferable to use
natural vegetated buffers, man-made buffers in the form of river-
training structures and bank protection devices (see Appendix C)
may be necessary where natural buffers do not exist or are too
low to be ef feet i ve.

i) Flood-flow buffer design, as discussed in Appendix A,
should include consideration of:

• Buffer location with respect to the active channel (s)
and the material site

• Buffer width sufficient to withstand anticipated
erosion without jeopardizing the integrity of the
buf f er

• Buffer height sufficient to divert floods

ii) Important variables to the selection of buffer location,
width, and height include:

• Channel configuration

• River size

• Hydrology

• Active channel alignment

• Channel aufeis

• Permafrost or ice-rich banks

• Type of vegetation

38 V. SITE PREPARATION

• Soi I compos i t i on

iii) Recommended flood-flow buffer designs are listed below
for scrape and pit gravel removal operations:

• Scrape - In these sites, it is recommended that the
site be protected from channel diversion by a buffer
for at least 5 to 8 years. This al lows the vegetation
to become re-established. The following Table lists
recommended minimum buffer widths for different river
s i zes:

N\i n imum width
River size (m)

Sma I I 15

Medium 35

Large 50

- The width can be reduced to half the recommended
minimum at the downstream end of the scraped site

- The height of the buffer should be at least as
high as the water level during a 5-year flood

• P i t - In these sites, it is recommended that the
site be protected from channel diversion by a flood-
flow buffer for a period of at least 20 years. This
provides a more long-term protection of the newly
created habitat. The following Table lists recommended
minimum widths for different river sizes:

Mini mum width
River size (m)

Sma I I 75

Medium 150

Large 250

V. SITE PREPARATION

- The width can be reduced to 20 percent of the
recommended minimum at the downstream end of the
pit

- The height of the buffer should be at least as
high as the water level during a 20-year flood

iv) Flood-flow buffers should be designed on a site-specific
basis following the guidelines presented in Appendix A
under any of the following conditions:

• The material site is on a very large river (e.g.,
Yukon River, Kuskokwim River, Tanana River, and
Co I V i II e R i ver )

• The available space does not allow for a buffer of
recommended width

• Buffer height is lower than the recommended design
height

• The active channel is angled into the bank at an angle
greater than about 30 degrees

• Channel aufeis occurs in the river adjacent to the
s i te

• Banks consist of primarily sands, are sparsely vege-
tated, or are ice-rich permafrost material

• Evidence of active bank erosion is found during the
site visit

4. Temporary dikes should be constructed around the site if the site
will be inundated during operation (Figure 7). Refer to Appendix
C discussing river-training structures.

40 V. SITE PREPARATION

a. Very large braided river

b- Medium braided river

c. Medium split river

d. Large meandering river

Figure 7. Potential locations of temporary dikes constructed around sites
having the potential to flood during site operation.

v. SITE PREPARATION

a. These structures should be constructed to minimize disturbance
to low- flow channels

b. Dikes should be constructed of on-site gravel materials

c. Fish entrapment should be avoided at all times

5. In cases where vegetated areas cannot be avoided, clearing should
proceed using the following guidelines:

a. If possible, sites containing dense vegetative cover should
be cleared during periods that do not coincide with periods
of bird and mammal breeding, nesting, and rear i ng-of-young.

In most cases fall would be the most desirable period for vege-
tation remova I .

b. When mature timber must be cut, It should be salvaged for pri-
vate or commercial use. If no such use exists, timber should
be ei ther :

• Stockpiled out of the active floodplain

• Used in site rehabilitation of adjacent material sites

• Hauled to designated disposal areas

• Piled and burned in accordance with appropriate regulations

6. Other vegetation and organic overburden can be mechanically cleared
and should be collected. This material should be saved for possible
use during site closure. At sites located in inactive floodplains

or terraces, this material should be broadcast over the surface during
site closure. In sites located only in an active floodplain, this
material can be piled (not broadcast) within the site according to the
following recommendations. The presence of this material in the materi-

42 V. SITE PREPARATION

al site in an acceptable manner will facilitate more rapid vegetative
recovery and subsequent fauna recovery.

a. If the site occurs only within an inactive floodplain or terrace
in any configuration or size river, the material should be tempo-
rarily stored either:

• In piles within or on the edge of the material site

• In a temporary storage area outside the material site (such
as an approved disposal area, material site, or unvegetated
inact i ve f loodp lain)

b. If the site occurs only within an active floodplain, vegetative
slash and organic overburden should be disposed of based upon
river configuration:

i) If located in a braided river this material should not
be piled or broadcast in the active floodplain of these
systems

ii) If located in a meandering, sinuous, split, or straight
river this material can be handled as follows:

• If sufficient space exists away from the active chan-
nel, store this material in piles within the material
site. On-site storage should occur at a location
that reduces repeated handling. During storage the
material can be stockpiled in as small an area as
possible to reduce excessive site enlargement to
compensate for covered gravel. These materials should
be stockpiled in a location and in such a manner
that slope failures and erosion would not endanger
the adjacent stream or have other adverse effects.
These piles should be:

43 V. SITE PREPARATION

- Located away from active channels

- Long and narrow

- Orientated parallel to the flow

- Of sufficient height to be above the 2-year flood

- Armored on the active channel side to prevent
erosi on

Refer to Figure 8.

• If insufficient space exists within the mined area
away from active channels this material may be stored
in:

- An approved disposal area

- An upland area

- Other material sites

- Unvegetated inactive floodplains

7. Settling ponds are recommended if the materials are to be washed
within the material site. Ponds should be protected with dikes de-
signed for the 10-year flood. Ponds generally should be located as
far from the active channel as possible. See Appendix F for guidelines
to be considered in the design of settling ponds.

B. SPECIFIC GUIDELINES FOR SCRAPED SITES

I. Material sites worked during the open-water season should be pro-
tected from flows corresponding to at least the 2-year recurrence

44 V. SITE PREPARATION

Terrace

Ij^t-r^^ctive Channel

High-Water Channel

Storage of
Overburden

Riprap to Level
of 2-Year Flood

-High Water Channel

Figure 8. Typical view of temporary storage of overburden showing desirable
location, shape, and armor protection.

interval flood by dikes designed to withstand such floods without
erosion. These dikes should not encroach on the low-flow buffer. The
purpose of the dikes is to reduce the probability that flow will pass
through the active site, thus reducing the potential for introducing
high concentrations of fine sediments into flows that are incapable of
transporting them to normal dispositional areas.

V, SITE PREPARATION

2. I f an unvegetated site is armored by coarse gravels or cobbles that
do not meet project material specifications, they should be stock-
piled, used in a dike, or otherwise saved for dispersal over the
site during site closure.

3. If it is necessary to locate a material site in an active side chan-
nel, it should first be diked off at the upstream and downstream
ends. The dikes should be constructed to a height corresponding to at
least the stage of a 5-year flood flowing in only the other chan-
nel(s). The side of the dikes facing the active channel should be
protected against erosion during such floods. Floods larger than this
may be allowed to overtop the dikes and flow through the material
site. Following large floods the downstream dike should be breached to
allow fish escapement.

V. SITE PREPARATION

Site Operation
Section VI

Page

GENERAL GUIDELINES 48

SPECIFIC GUIDELINES 49

Site Matr i ces

Special Instructions 50

Braided Rivers 57

Split Channel Rivers 60

Meandering, Sinuous, and

Straight Rivers 63

Scraped Sites 65

Pit-Excavated Sites 70

Dredged Sites 74

Site Operation
Section VI

A. GENERAL GUIDELINES

1. Changing the course of any active channel should be avoided

2. All gravel removal operations should be conducted in a clean and
efficient environmentally acceptable manner. For example:

a. All fuels and toxic materials should be stored out of the flood-
plain

b. Avoid fueling and servicing equipment within the active flood-
plain to reduce spills and disposal of materials (e.g., used
crankcase oil and lubricants)

c. The by-products from support operations occurring at the material
site (such as gray water, domestic sewage and solid waste) should
be disposed of in an approved fashion (consult current Federal
and State regulations). In general these by-products should

not be discarded within the active or inactive floodplains with-
out proper treatment.

3. Floodplain access and travel should occur only as designated in the
approved work plan

4. Buffer zones should not be disturbed in any manner that would reduce
their function. For example:

a. Vegetative structure, width, and banks of flood-flow buffers
should not be altered

b. Heavy equipment should not repeatedly traffic low-flow buffers,
or reduce their height or configuration

48 VI. SITE OPERATION

5. The approved work plan should be followed. If unexpected conditions
are encountered in the field, operators should:

a. Immediately notify the appropriate agency of the encountered
situation, and anticipated work deviation

b. Proceed in a manner that closely follows this manual until the
permitting agency responds

6. Gravel washing operations within the floodplain, settling pond use,
and washing activities should be conducted per the general recommen-
dations provided in Appendix F. In general:

a. Where gravel washing operations are required, the wash water
should be recycled with no effluent discharge to the active

f loodp lain

b. If settling ponds are required, they should be designed to pro-
vide adequate retention time for site-specific conditions. The
outflow structure should be perched to avoid fish entrapment.

c. The use of a flocculant may be necessary to meet the Federal-
State effluent standards

B. SPECIFIC GUIDELINES

Specific guidelines for site operation have been developed for rivers
of different configuration and size, and for different gravel deposit
locations in each configuration and size. The proposed site should be
closely matched with the following matrix Tables which direct attention
to specific guidelines applying to scraped, pit excavated, and dredged
si tes.

'^'^ VI. SITE OPERATION

This section is organized in four parts, as follows:

Page

I. Use of Guidelines Matrices

Gui de I i nes
Based on
River Type

Special Instructions 50

Braided Rivers - Matrix I, with general

guidelines statements 57

Split Channel Rivers - Matrix 2, with

general guidel ines
statements 60

Meandering, Sinuous, and Straight Rivers -
Matrix 3, with general
guidelines statements 63

Spec i f i c Gu i de-
I ines Based on
Mining Method

2. Scraped Sites

3. Pit Excavated Sites

4. Dredged Sites

I. Use of Guidelines Matrices

SPECIAL INSTRUCTIONS

River Configuration

Each of the three matrices is designed for a specific river config-
uration. The guidelines for one river configuration are not identical to
those for another configuration, thus the user must be careful that the
proper matrix for the river in question is being used. The configurations
represented by the three matrices are:

VI . SITE OPERATION

• Braided Rivers (Watrix I)

• Split Channel River (Matrix 2)

• Meandering, Sinuous, and Straight Rivers (Matrix 5)

Braided Rivers. A braided river typically contains two or more inter-
connecting channels separated by unvegetated gravel bars or vegetated islands
(Figure 9a). Its floodplain is typically wide and sparsely vegetated, and
contains numerous high-water channels. Bars separating the channels are
usually low, gravel surfaced, and easily eroded.

Split Channel Rivers. A split channel river has numerous stable islands
which divide the flow into two channels (Figure 9b). There are usually no
more than two channels at a given reach and other reaches are single channel.
The banl<s of the channel (s) are typically vegetated and stable. The split
river floodplain is typically narrow relative to the channel width.

Meandering, Sinuous, and Straight Rivers. Meandering and sinuous rivers
(Figures 9c and 9d) have a single channel that winds back and forth within
the floodplain; straight rivers wind less. Very few islands are found in
these systems. Point bars and lateral bars are common, with point bars more
frequent in meandering rivers and lateral bars in straight rivers. Banks on
the outside of a bend in a meandering river are normally unstable whereas the
banks of a straight river are relatively stable. The floodplains of mean-
dering and sinuous rivers are usually as wide as the meander belt, and there-
fore, are narrower for sinuous rivers than for meandering rivers. Floodplains
of straight rivers are narrow.

Template Preparation

Required Data. After the proper matrix has been identified, the template
describing the work plan can be prepared. A template can either be prepared
by: (I) using the blank template provided in the back of this manual, or (2)
aligning a blank sheet of paper under the parameter descriptions of one of the

^' VI . SITE OPERATION

^;®?=*'"

i|SEv

^S*.

a. Braided River

b. Split Channel River

C. Meandering River

"3?

d. Sinuous River

Figure 9. Examples of river configurations (straight rivers
are similar to sinuous but with a lower sinuosity ratio).

VI . SITE OPERATION

matrices, drawing lines on the blank sheet to correspond to ttiose of the
heading columns and identifying each parameter in its proper position. An
example of a template will be shown later (Figure 12a). To fill out the tem-
plate the following information ia required:

• The size of the river at which the mining operation will be conducted
(small, medium, or large)

• The site location or locations with respect to floodplain type (active,
inactive, terrace) (see Figure 10)

c
O

hannel

Channel
annels

■o

^ s 6

III

•^ -^_ ,i— . .j'^^ywfk'^

ryxXrha^

i2i& <

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—

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^^^'"^^^

Terrace

Inactive

Floodplain

Active Floodplain

Terrace

/ \

' \

A A 1 /

Figure 10.

Floodplain location types.

• The type of channel or channels associated with the desired gravel
deposit (active, high-water, abandoned) (see Figure II)

• The type of gravel deposits to be mined (see Figure II)

Fi I I ing Out a Template. For each individual template evaluation, only
one river size, site location, and associated channel can be used. Any number
of deposit types can be used as long as they are all associated with the
same floodplain and channel type being considered.

VI . SITE OPERATION

Outside
Meander

Inside
Meander

^; — Vegetated Banic

^ Outside
Meander

Island

Inside
Meander

Vegetated Bank

Lateral Bar

Vegetated Bank

rlgure Jj. Types of deposit

I. Place an "X" under the template space which corresponds to the indi-
vidual parameter being considered (Figure 12a).

VI . SITE OPERATION

Sne

Sire

X XX,

Ml 9

/Jas<c

Is ¥> •» i t: * 5

lypEof

i^ioimOum»i eePosrr

River
Sue

a. Prepare Teinplate

SPLIT CHANNEL RIVER

U C IT) «) W

River
Size

E
% 1 S,

^15

SPL

sue

Location

c
£ 5
5 a
a o
o o

"- ; «
S S iil
5 !^ E
< £ "

IT CH*

Assoc

Channel

ill
HI

NNEL RIVER

Typeot Deposit

» ? ^

" - 1 1 s

• " i 1 ? 1 1

" s 2 « c 2 ;
2 1 1 1 II II

mo- _.I£o>>

CommenI Number

3«

)<.

II!

5l?

Its

111

8
9
10

tov

HO.

7
i

Offl

CommenI Number

b. Compare to

Appropriate

Matrix

c. Find Comment Number for
Type of Deposit Desired

d. Search for Additional
Matches if Multiple
Deposits are Checked

River
Size

- 1 .
Ill

^ -i. -i

SPL

Sue
Location

c 1

3 a
a T3

° \L

ill

< S *

ri CH/

Assoc
Channel

s 1 ?

< I <

MNEL RIVER

Typed Deposit

1 s i 1 =
. 5 s s 1 s s
s 1 1 I s i i

Comment Number

34i-

eN-

III

5/T£

U>orf»o4

AsScc.

beposr

Figure 12. Example of how the completed template is matched to determine
availability of gravel.

2. When the template is complete, compare the template to the appropriate
matr i X ( F i gure I 2b ) .

5. Follow down the matrix until river size, site location, associated

channel, and one deposit type are matched (Figure 12c). Record Comment
Number .

4. If more than one deposit has been "X"ed, continue down until another
match is found, then record Comment Number (Figure I2d).

5. After all deposit types have been matched, read the appropriate guide-
lines Comment(s) to determine if and how gravel is available. Specific
mining guidelines are referenced.

6. Repeat steps I to 5 for other combinations of floodplain and channel
type.

VI . SITE OPERATION

c
a>

E
E

o
o

1. Gravel may be available by scraping
or dredg i ng .

2. Gravel available by scraping.

3. Gravel available by scraping.

4. Generally should not be mined.

5. Banks should not be mined.

6. Gravel available by scraping.

7. Gravel available by scraping.

8. Gravel available by scraping or pit
mining.

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VI . SITE OPERATION

Expanded Comments for Braided Rivers

Comment- I. Generally, the bed of an active channel should not be dis-
turbed. If bed deposits are the only available source, the gravel should
be taken only under strict work plans and stipulations.

• It is recommended that side channel (s) be mined rather than the main
channel. Select side channel (s) that carry less than approximately
one third of the total flow during the mining period; block off up-
stream ends and mine by scraping operations. Refer to Scraping Guide-
I ines (VI B 2) .

• If the main channel must be mined, dredging may be an appropriate
method. Refer to Dredging Guidelines (VI B 4).

Comment 2. Gravel is available by scraping gravel deposits to near the
low summer flow, maintaining appropriate buffers, or no lower than the water
level present during the mining operation. Refer to Scraping Guidelines (VI B
2).

Comment 3. Gravel is available by scraping such that the configuration
of the channel is not greatly changed and there is not a high probability
of channel diversion through the mined area. Refer to Scraping Guidelines
(VI B 2).

Comment 4. Vegetated islands are often a limited habitat in these systems
and should generally be excluded from the work plan. Exposed deposits should
be considered before vegetated island deposits. If deposits in feasible alter-
native locations are not sufficient, and vegetated islands are abundant in the
particular reach in question, up to about 10 to 20 percent of this habitat may
be removed from about a given 5-km length of the floodplain. Refer to Scraping
Guidelines (VI B 2) or Pit Guidelines (VI B 3).

Comment 5. Vegetated river banks of both active and high-water channels
should not be disturbed because of biological and hydraulic alterations.
These should be removed from work plans.

VI . SITE OPERATION

Comment 6. Gravel is available by scraping within the channel, but the
general configuration of the channel should be maintained. Refer to Scraping
Guidel ines (VI B 2).

Comment 7. In these systems it is recommended to scrape exposed deposits
in the active floodplain. If sufficient gravel is not available in the pre-
ferred deposits, gravel may be available by scraping in these locations, but
the general configuration of the channel should be maintained. Refer to Scrap-
ing Guidel ines (VI B 2) .

Comment 8. In these systems it is recommended to scrape exposed deposits
in the active floodplain. If sufficient gravel is not available in the pre-
ferred deposits, gravel is available in these locations by either pit or
scrape methods. Generally, pits should only be considered when more than
50,000 m are required. Refer to Scraping Guidelines (VI B 2) and Pit Guide-
I ines (VI B 3).

^^ VI. SITE OPERATION

CN
X

cr
<

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0)
E
E
O

1. Gravel may be available by scraping
or dredging.

2. Gravel available by scraping.

3. Some gravel may be available by
scraping or pit.

4. Generally should not be mined.

5. Banks should not be mined.

6. Gravel available by scraping.

7. Should not be mined.

8. Generally avoid, not much available.

9. Gravel available by scrape or pit.
10. Gravel available by scraping.

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SITE OPERATION

Expanded Comments for Split Rivers

Comment I . General ly the bed of an active channel should not be dis-
turbed. If bed deposits are the only available source, the gravel should
be taken by dredging or scraping under strict work plans and stipulations.

• It is recommended that side channel (s) be mined rather than the main
channel. If the site contains a side channel that caries less than
approximately one third of the total flow during the mining period this
channel can be blocked at its upstream end and mined by scraping.
Refer to Scraping Guidelines (VI B 2).

• If channels approximating this size are not available then either

the side or main channel can be mined using dredging. Refer to Dredging
Gu i del ines (VI B 4) .

Comment 2. Gravel is available by scraping deposits to near the low
summer flow, maintaining appropriate buffers, or no lower than the water level
present during the mining operation. Refer to Scraping Guidelines (VI 8 2).

Comment 3. Gravel is available if suitable buffers are maintained to
protect against channel diversion. Refer to Scraping Guidelines (VI B 2),
Pit Excavation Guidelines (VI B 3), and Buffer Recommendations (V A 3 and
Append i x A ) .

Comment 4. Vegetated islands are often a limited habitat in these systems
and often control channel integrity. Exposed deposits should be considered
before vegetated island deposits. If deposits in feasible alternative loca-
tions are not sufficient, and vegetated islands are abundant in the river
system in question, about 10 to 20 percent of this habitat may be removed from
about a 5-km reach of floodplain. Refer to Scraping Guidelines (VI B 2) and
Pit Guidel ines (VI B 3) .

Comment 5. Vegetated river banks of both active and high-water channels
should not be disturbed because of biological and hydraulic alterations.
These areas should be removed from work plans.

VI . SITE OPERATION

Comment 6. Gravel is available by scraping in the high-water channel,
but precautions must be taken to avoid channel diversion. Refer to Scraping
Guidel ines (VI B 2).

Comment 7. Mining is not recommended in or near the active channel of
small split channel rivers because there is not much material available.

Comment 8. There generally is not much material available in these de-
posits and they should be avoided. If only a small amount (<I0,000 m ) of
gravel is needed, these deposits may be considered for scraping. Refer to
Scraping Guidelines ( iV B 2).

Comment 9. Grave! is available by either pit or scrape methods. Generally
these should be considered for large amounts of gravel that are not present
in adequate amounts in exposed deposits. Pits should be considered when more
than 50,000 m are required. Refer to Scraping Guidelines (VI B 2) and Pit
Guidel ines (VI B 3) .

Comment 10. Some gravel is available by scraping, but the general config-
uration of the channel should be maintained. Refer to Scraping Guidelines
(VI B 2).

62 VI. SITE OPERATION

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1. Some gravel may be available by
dredg i ng .

2. Gravel available by scraping.

3. Some gravel may be available.

4. Not recommended in these systems.

5. Banks should not be mined.

6. Gravel available by scraping.

7. Should not be mined.

8. Generally avoid, not much available.

9. Gravel available by pit or scrape.

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VI . SITE OPERATION

Expanded Comments for Meandering, Sinuous, and Straight Rivers

Comment I . Generally the bed of an active channel should not be dis-
turbed. If bed deposits are the only available source, the gravel should
be taken by dredging only under strict work plans and stipulations. Refer
to Dredging Guidelines (VI B 4).

Comment 5. Gravel is available if suitable buffers are maintained to
protect against channel diversion. Refer to Scraping Guidelines (VI B 2),
Pit Guidelines (VI B 3), and Buffer Recommendations (V A 3 and Appendix A).

Comment 4. Vegetated islands are rare in these river systems and should
not be disturbed. It is recommended they be removed from the work plan.

Comment 5. Vegetated river banks of both active and high-water channels
should not be disturbed because of biological and hydraulic alterations. These
areas should be removed from the work plan.

Comment 6. Gravel is available by scraping in the high-water channel,
but precautions must be taken to avoid channel diversion. Refer to Scraping
Guidel ines (VI B 2) .

Comment 7. Mining in the active or high-water channels of these small
rivers is not recommended because there is not much material available.

Comment 8. There generally is not much gravel available in these deposits
nd they should be avoided. If only a small amount (<I0,000 m ) of gravel
s needed, scraping may be considered. Refer to Scraping Guidelines (VI B-2 ) .

Comment 9. Gravel is available by either pit or scrape methods. Generally
these areas should be considered for large amounts of gravel that are not

VI. SITE OPERATION

present in adequate amounts in exposed deposits. Pits should be considered
wtien more than 50,000 m are required. Refer to Scraping Guidelines (VI B 2)
and Pit Guidel ines (VI B 3) .

2. Specific Guidelines for Scraped Sites

a. Gravel bars adjacent to high-water and abandoned channels can
be scraped to a specified level at the edge of the channel and
should be sloped toward the channel to provide proper drainage.
An average maximum depth should be maintained in the channel to
provide for flow containment during periods of low flow within
the channel. The average maximum depth at any point along the
channel is the distance between the average thalweg profile line
and the channel-full stage at that point (Figure 13).

-Sianne/ -Fu//

Channel -Ful

Average Maximum ^'^^^

Thalweg Profile

Average Thalweg Profile

Channel Thalweg
Cross Section A-A

Figure 13. Definition of average maximum depth and channel-full width in a
channe I .

Recommended values of maximum depth that should be maintained in
the channel are listed below for three ranges of channel-full
width. Values of half the recommended depths should be considered
minimum depths below which flow containment would be ineffective.

VI . SITE OPERATION

Braided Configuration

Recommended maximum depth (m)
Channel-full High-water channels Abandoned channels
width
(m)

0-5 0.30 0.05

5-50 0.50 0. 15

30 or greater 0.80 0.50

Split, Meandering, Sinuous, and Straight Configurations

Recommended maximum depth (m)
Channel-full High-water channels Abandoned channels
width
(m)

0-5 0.40 0. 15

5-30 0.60 0.30

30 or greater 1.00 0.60

b. Gravel bars adjacent to active channels can be scraped to a

specified minimum level and should be sloped toward the channel
to provide proper drainage. The purpose of a minimum level is
to minimize hydraulic change to the active channel at low flows.
The recommended minimum level of gravel removal is controlled
by the highest of the following three levels:

VI . SITE OPERATION

• The upper level of the low-flow buffer. This is defined
in Site Preparation Guidelines (V A 5a)

• The level corresponding to 0.15 m above the average water
level expected during the gravel removal operation

• The level that will maintain a specified averaye maximum
depth in the channel (Figure 15). Recommended values and
minimum values of maximum depth that should be maintained
are listed below for three channel width ranges at channel-
full flow. Values of half the recommended depths should be
considered minimum depths below which hydraulic change is
more likely to occur.

Braided Configuration

Channel-ful I Recommended

width maximum depth

(m) (m)

0-5 0.50

5-50 0.50

50 or greater I .00

Split, Meandering, Sinuous, and Straight Configurations

Channel-full Recommended

width maximum depth

(m) (m)

0-5 0.50

5-50 I .00

50 or greater I .50

VI . SITE OPERATION

c. Scraping in high-water and abandoned channels should follow
the alignment of the channel. Gravel removal design depends
on several factors listed below:

• Side slopes should be stable for expected flow conditions
during a 2-year recurrence interval flood. This will reduce
the potential for rapid channel shifting.

• Channel-full top width should not be increased if it can
be avoided. If additional material is needed that cannot
be obtained from other dry channels or unvegetated bars,

the channel being worked can be widened to a width no greater
than that of the active channel and preferably half that of
the active channel (especially on meandering, sinuous, and
strai ght r i vers) .

• Longitudinal channel slope into the material site should not
exceed 10 times the average slope of the channel (Figure 14).
This will minimize the potential for extensive upstream bed
degradation. The upstream end of the section of increased
slope should be a sufficient distance from the nearest active
channel to minimize the potential for channel diversion.

Top of Adjacent Bar or Bank

Original Channel Bed

^//// MatenaTRemoved^

•^'-UUl-i LJU.U ij-ijjuju UjIl/Uj

-Slope < 10 X Overall
Channel Slope

Maintain Positive Slope-
Low- Flow Buffer

Figure 14. Sketch of high-water or abandoned channel longitudinal
profile showing recommended channel bed slopes resulting from scrap-
ing the channel bed.

VI . SITE OPERATION

• Longitudinal channel slope out of the material site at the
downstream end should not be adverse (bed elevation in-
creasing in the downstream direction). Adverse slopes cause
ponding and potential fish entrapment. Maintaining a positive
slope (bed elevation decreasing in the downstream direction)
is recommended to allow for channel drainage during a flood
recession. The downstream end of the disturbance should be
separated from the nearest active channel by at least the
width of the low-flow buffer for that channel (Figure 14).

d. Scraping in active side channels that have been diked and de-
watered should follow the alignment of the channel and should
stay between the low-flow buffers. Gravel removal design depends
on other related factors listed below.

• Side slopes should be stable for expected flow conditions
during a 5-year recurrence interval flood. This will minimize
the potential for slope failure and subsequent deterioration
of the low- flow buffer.

• The width of excavation is limited by the limits of the
low-flow buffers (Figure 15). The bottom width is limited
only by the equipment used.

""^^

Low-Flow
Buffer -

Low Summer Flow Stage

Maximum Excavation Width

Stable Side Slopes

-^WA^

777}

Material Removed '

Low -Flow
^—Buffer

Figure 15. Sketch of active side channel cross section defining
excavation limitations.

VI. SITE OPERATION

• Channel slope into and out of the material site should be
stable under all flow conditions up to and including a 5-year
flood. This will minimize the potential for bed degradation.

• The existing pool-riffle sequence should be retained during
the gravel removal operation. If it is disturbed, a similar
sequence should be restored following the operation.

• Active channels scheduled for winter scraping should be
evaluated for the presence of flowing water in and downstream
from the site; if water is present, the site should not be
mined.

e. Mining of high-water or abandoned channel bed and associated bars
should follow Guidelines VI B 2c and VI B 2a, in that order, if
sufficient gravel quantities are not available from only one of
these sources. If sufficient gravel quantities are still not
available and channels are not abundant, or if high-water or
abandoned channels are not available, it may be necessary to form
new wel l-def i ned channels following Guideline VI B 2c. High-water
channels formed during the gravel mining operation should have an
alignment similar to that of natural high-water channels or the
active channel (s) of the river.

3. Specific Guidelines for Pit-Excavated Sites

A profile and configuration of the work area should be maintained
to provide:

a. A minimum surface area of 2.0 ha. Inundated pits smaller than
this size are generally not heavily utilized by waterfowl. If
the pit is connected to the river, a mean depth of 2.5 m or
greater should be provided to insure winter survival of fish.

VI . SITE OPERATION

b. A relatively long and narrow shape aligned longitudinally in
the floodplain and providing an irregular configuration with
islands and peninsulas is preferable (Figure 16a and 16b)

• Islands and low peninsulas provide more diverse shoreline
and aquatic habitats

• If the river does divert through the pit, it will have an
alignment to follow and will more quickly develop into a
channel configuration

c. An outlet channel for a path of low resistance when the pit is
inundated, reducing erosion of undisturbed terrestrial habitat.
An outlet channel also provides an avenue of escape for fish
which may become trapped during high flows.

• Outlet channels should be deep enough to allow fish passage
during low flow conditions and be as narrow as possible

• All outlet channels should be on the downstream end of the
pit to prevent premature degradation of the stream channel
and p i t

• Outlet channels should be connected to a non-depos i t i ona I
area of an active channel and be angled downstream

• Outlet channels should not be of straight line configuration

• Outlet channels should be constructed at the end of the
site closure to minimize siltation in the river

d. A diversity of water depths and bank slope

• At least 30 to 50 percent of the shoreline should have a
gradual slope to provide areas for emergent aquatic vegeta-

VI . SITE OPERATION

a. Aerial view of an acceptable pit configuration.

Deep Regior

Island

Marsh/
Littoral Area-N Lowland-

b. Side view of an acceptable depth regime (Section A -A).

Figure 16. Example of a preferred shape and depth profile of gravel
pits in floodplain terraces and connected to the active channel.

VI . SITE OPERATION

tion, shorebird and wateffowl feeding, juvenile fish rearing,
and muskrat habitat (Figure 16b). The gradual slope of these
areas should allow a natural transition of vegetative com-
munities and provide exposed mud flats or the potential
for future marsh habitat development.

• The remaining shoreline should be more steeply sloped to
provide habitat more beneficial to other groups such as
diving ducks, geese, swans, beaver, and adult fish

• As mentioned above, a mean depth of 2.5 m or greater of
combined littoral and deep areas should be provided if there
is an outlet channel or if a non-connected pit is to be
managed for fish. For example, 25 percent littoral area
averaging 0.5 m and 75 percent deep area averaging 3.2 m
yields an overall mean depth of 2.5 m. Refer to the Pit
Design Appendix D.

• In a pit not connected to the active channel, and not to be
managed for fish, a similar shape and depth configuration is
appropriate, but a mean depth of 2.5 m is not required. These
pits should be protected with an adequate buffer from flood-
ing so that fish entrapment is minimized. In this case, the
main purpose is the creation of shorebird and waterfowl

hab i t at .

• If there is a choice between mining to a shallow depth over
a broad surface area or deep over a restricted surface area,
the choice should be to increase depth before increasing
area. This minimizes terrestrial disturbance and reduces the
probability of fish winter mortality.

VI . SITE OPERATION

4. Specific Guidelines for Dredged Sites

a. Active channels scheduled for winter dredging should be evaluated
for the presence of flowing water in and downstream from the
site; if water is found, the site should not be mined

b. Depth of excavation in an active channel should be limited by
the width of the low summer flow channel minus the low-flow buf-
fer; the side slopes should be designed to remain stable during
5-year flood flows

c. The length of excavation in a pool of the active main channel
should not exceed the length of the pool. If a riffle is to

be mined, the length of excavation should not exceed the average
length of the pools within 5 km up and downstream of the site.

d. The bed slopes at the upstream and downstream ends of the active
channel excavation should be designed to remain stable during
5-year flood flows to minimize the potential for degradation

VI. SITE OPERATION

Site Closure
Section VII

Page

GENERAL GUIDELINES 76

SPECIFIC GUIDELINES 80

Scraped Sites 80

Pit-Excavated Sites 80

Dredged Sites 81

Site Closure
Section VII

A. GENERAL GUIDELINES

After mining is completed, material sites should be rehabilitated to
return them, as closely as is possible, to pre-mining condition.

1. The site should be sloped and contoured immediately following comple-
tion of operations. In cases where sites consist of two or more
aliquots, each should be sloped and contoured as completed. Any
seeding and fertilizing should be done in spring or summer.

2. The work area should be shaped and contoured to minimize ponding
and to blend with surrounding features and topography

5. Access roads, culverts, and bridges should be removed (unless other-
wise approved) and the areas restored. Fill ramps at incised banks
should also be removed and the bank stabilized (if damaged) to
minimize subsequent erosion.

4. All manmade debris should be removed from the site

5. All cut slopes encountered during gravel removal or access road
construction should be stabilized to prevent thermal, fluvial, and
wind erosion

6. Dewater settling ponds of the clear surface water either by pumping
or lowering dikes. Silt may be:

• Left in place in inactive floodplains and terrace locations;
protective structures should be lowered to a level corresponding
to the level of the impounded silt

^^ VI I. SITE CLOSURE

• Broadcast or piled with ottier overburden and vegetative slasti
and debris (refer to guideline VII A 7)

• Removed from active floodplain sites to approved disposal areas

7. In general, at sites ttiat were previously vegetated and will contain
nonflooded areas following site operation, rehabilitation should
facilitate natural revegetation and site recovery. When organic
overburden and vegetative slash and debris are available, it is
recommended that natural revegetation be favored over artificial
seeding and fertilization. Final placement of overburden and vege-
tative slash and debris should incorporate the following guidelines.

a. Active floodplains

i) In braided systems it is unlikely that any overburden or

vegetative slash and debris will be available. However, if
available it should not be piled within the active flood-
plain.

ii) In meandering, sinuous, split, and straight systems this
material may be piled within the active floodplain. The
design and loction of these piles should incorporate
the following (Figure 17). They should be:

• Located away from active channels and in areas where
they are subjected to the least hydraulic erosion

• Long and narrow in configuration (about 15-20 m long
and 3-5 m wide, where possible)

• Orientated parallel to the flow

• About I m above the 2-year recurrence flood at its top

^^ VII. SITE CLOSURE

Temporary Pile Shape.
During Operation

(Refer to Fig. 8)

Pile at
Closure-

At Least
15— 20m Long

Armor to 2-Year
Flood Stage

-At Least
3-5m Wide

2-Year Flood Stage

JZ^

Material Site,
Surface —

Figure 17. Typical view of desirable shape and configuration, relative to 2-year
flood levels, of permanent I y placed overburden piles.

• Armored on ttie active side to prevent erosion (refer
to discussions of bank protection in Appendix C)

• Piled to maximize surface area, provided ttiis meets
the above cr i ter ia

If sufficient material exists, it is desirable to produce
several piles distributed throughout the mined area.
If insufficient material exists to meet the above cri-
teria, it should not be piled within the active flood-

VII. SITE CLOSURE

plain. If insufficient space exists within the mined
area away from the active channel, this material may
be used either in site rehabilitation of adjacent material
sites or disposed of in approved upland areas.

iii) Neither artificial seeding nor fertilization should be
conducted in active floodplains

b. Inactive floodplains and terraces

At these locations in rivers of all configurations this ma-
terial may be either piled or broadcast over the ground surface

i) At sites consisting only of inactive floodplains that
are annually flooded it may be best to pile this ma-
terial rather than broadcast it to reduce downstream
transport. If piled, the guidelines presented above
(7a) should be followed.

ii) At sites including terraces and inactive floodplains
that are not annually flooded, this material should
be broadcast throughout these portions of the mined
site. In general, this material should be spread about
10 cm deep and should cover as large an area as pos-
sible.

iii) If this material is not available for use in site reha-
bilitation of terraces and inactive floodplains, arti-
ficial seeding and fertilization may be considered
and should follow current state-of-the-art techniques
for arctic and subarctic regions

^^ VI I . SITE CLOSURE

B. SPECIFIC GUIDELINES

1. Specific Guidelines for Scraped Sites

a. Distribute coarse gravels or cobbles, when available, over the
surface of the gravel removal area, to provide for a more rapid
rearmoring of the surface

b. If the low-flow buffer was disturbed, return it to its natural
configuration and height

c. At side channel sites which were diked to work in a dry con-
dition, remove the downstream dike and lower the upstream dike

to a level corresponding to the river stage of a 1.25-year flood.
This will prevent large quantities of sediment from being washed
from the site into the river at low-flow conditions.

2. Specific Guidelines for Pit Excavated Sites

a. Overburden and vegetated slash and debris should be:

• Broadcast or piled, or both, in the nonflooded portions of
the mine site, including islands and shorelines

• If any material remains, some may be placed in the flooded
portion of the site to provide nutrients and cover

b. Slope and contour shoreline banks and all overburden stockpiles
in nonflooded portions of the mined area to provide naturally
appearing configurations that blend with surrounding features.
These procedures should provide and maintain those characteris-
tics of diverse shoreline configurations and profile, bank slope,
and water depth as discussed in previous operation guidelines.

VII. SITE CLOSURE

c. Excess unused mined material should be used to form islands
or vary water depths within the pit

d. Fol low work plan regarding access to the pit

e. The outlet channel, if provided in work plan, should be con-
structed during the final phases of site closure. Refer to Opera-
tions Guidelines for design criteria (Section V I B 5c).

3. Specific Guidelines for Dredged Sites

If the low-flow buffer was disturbed, return it to its natural config-
urat ion and hei ght

VII. SITE CLOSURE

Appendices

Appendix Page

A. FLOOD-FLOW BUFFER DESIGN 84

B. FIELD INSPECTION:

Desirable Data, Procedures and

Equipment 107

C. RIVER-TRAINING STRUCTURES AND BANK
PROTECTION DEVICES 117

D. DESIGN OF PITS 127

E. FISH PASSAGE STRUCTURES 151

F. SETTLING PONDS AND WASTEWATER

TREATMENT 135

G. EFFECTS OF BLASTING ON AQUATIC

ORGANISMS 139

H. STANDARD FORMULA AND CONVERSION

FACTORS 145

I. GLOSSARY 157

APPENDIX A

FLOOD-FLOW BUFFER DESIGN

INTRODUCTION

Flood-flow buffers should be designed to prevent the diversion of an

active channel through the material site. The design life is usually some

finite period ranging from 5 years for some scraped sites to possibly 50 years
or more for some pit sites.

The recommended design procedure is to consider the lateral activity
of the particular river based on its channel configuration and historical
migration pattern. The river size, soil composition of the buffer material,
vegetative cover, permafrost banks, and channel aufeis are also important
considerations affecting the stability of the buffer. The hydrology of the
river must be considered to evaluate the frequency that the buffer will be
flooded. Each of these are discussed in more detail in the following sections.

BUFFER WIDTH

Lateral Channel Migration

The general procedure for estimating the amount of channel migration
of a river is summarized in this section. The user is referred to Brice (1971)
for a more detailed explanation of the procedure. Stereop lot ters, when avail-
able, are a faster and more accurate means of estimating lateral migration.
Additional information on stereop lot ter use can be obtained from photogram-
metry textbooks, photogrammetr ic consultants, or stereop I ot ter manufacturers'
I i terature.

Because of the complexities of the bank erosion process, quantifying
lateral migration usually involves the use of historical records. These are
projected based on a knowledge of the channel configuration and other con-
siderations discussed later. Aerial photographs are obtained of the reach of

river being studied (generally at least two floodplain widttis upstream and
downstream from the mined site location). Photographic coverage is desired for
as many years as are available, but should at least include photos 20 or more
years apart for the evaluation of long-term changes. The photos can be repro-
duced to obtain slides as described by Brice (1971) or can be used in print
form as described below:

I. Enlarge the photos to the same scale, whenever possible. Select three
or more identifiable features on each photo. Place an overlay over one photo
and mark the selected features on the overlay. Place the overlay over the
other photo(s) and match the features to these marks to verify that the scale
is the same. If the scales are identical, the river banks can be traced from
each photo on the same overlay (Figure A- I ) . The lateral migration can be
measured directly from the overlay. If the scales are not the same, the follow-
ing steps are necessary.

2. Select two identifiable features on each of the photos and connect
these to form a baseline (Figure A-2). These features should be located near
the opposite ends of the photograph.

5. Subdivide the baseline into 10 or more segments and draw lines perpen-
dicular to the baseline through each of the segment endpoints, extending
the line through the area for which the lateral migration estimates are de-
sired. Subdivide one of these lines and draw lines perpendicular to form a
grid pattern (Figure A-5).

4. Prepare a similar grid to any desired scale on a sheet of paper.
Transfer bank locations at each grid square boundary from each photo to the
corresponding grid square boundary on the sheet of paper (Figure A-4). The
rows and columns can be numbered and/or lettered to assist in the coordination
of the transfer.

5. Connect the points on the paper to show the bank positions as they
appear on the photos (Figure A-5). The smaller the grid is on the photos,
the more accurate the bank lines will be. Lateral migration can be measured
directly from this figure.

Figure A- I . Schematic of overlay showing topographic features
used as match points and bank lines from 1948 and 1978
photographs.

Small grove of trees
in clearing — -y

Point of terrace-

Figure A-2. Schematic showing the selection of features to use
as baseline endpoint for a portion of the study reach.

Grid

Figure A-3. Schematic showing the development of a grid on each
photo.

The accuracy of this technique is sufficient for estimating the expected
life of the buffer zone or, conversely, the required width of the buffer
to meet the design life expectations. The accuracy of the average annual
migration is greater for longer time periods between photo dates. Brice (1971)
notes that the accuracy depends on the original scale and definition of the
photos, the scale of the enlargement, the degree of scale distortion in the
photo, the numbers and reliability of features used as reference points,
and the care used in matching. It is generally not advisable to use the edge
of lakes or rivers as reference match points or as bank lines for migration
estimates because of the variability of this feature with water level changes.

Channel Configuration

Channel configuration is an important parameter in evaluating the poten-
tial for extending past records into the future. Each configuration is dis-
cussed separately in the following sections. The effects of buffer height
are discussed in a different section.

Braided Configuration. Braided river channels are often very active
laterally within the active floodplain. When a major active channel is flowing
along a vegetated cut bank, substantial bank erosion can take place. If the
major channel was flowing along the bank during the entire period over which

Figure A-4. Schematic show
to the paper grid.

ng the transfer of the bank

I nes

from the photos

Erosion

Deposition

Erosion

Figure A-5. Completed schematic showing bank
lines and zones of erosion and deposition from
which rates of erosion can be measured.

the historical migration rates were estimated, that migration rate may be
projected into the future. Otherwise, different locations on the floodplains
should be selected for obtaining estimates. Any change in the alignment of the
channel should be accounted for, with erosion rates increasing for increasing
angles of the channel to the bank. A factor of safety should be applied to the
result, its value depending on the confidence one has in the estimate for a
given system.

As a hypothetical example, consider the length of bank labeled A in
Figure A-6. The dashed line shows the channel as it appeared in 1950 and the
solid line represents the location of the 1975 river channel. Assume that the
lateral migration of bank A was measured to be 100 m, or 4 m per year. Assume
it is desired to have a buffer lasting at least 8 years to protect a scraped
gravel removal area in the inactive floodplain. Projecting the past into
the future results in 4 m per year for 8 years, or 32 m.

Figure A-6. Schematic of a river with a braided configuration with the 1950
and 1975 channel locations shown.

• The 1950 channel alignment was at a larger angle to the bank than the
1975 channel; thus it Is likely that the erosion rates were greater
than 4 m per year for the 1950 alignment and less than 4 m per year for
the 1975 alignment. The 32 m can thus be reduced slightly, possibly to
28 m. If intermediate photos (between 1950 and 1975) are available,
this figure can be substantiated by estimating the erosion rate for the
more recent time period. If the year to year activity of the active
channels is relatively low, it can be assumed that the potential for a
significant change in alignment is low, and a fairly low safety factor
can be used. In this case, a safety factor of 1.5 applied to the 28 m
value would result in a buffer width of 42 m.

• If the active channels are known to change substantially every year,
the reduction for alignment should not be applied and a safety factor

of 2,0 or more could be used. This would result in a buffer width of 52
m X 2.0, or 64 m.

It is possible to find a braided configuration where the length of bank
defining the buffer is not adjacent to an active channel, e.g., area B in
Figure A-6. In this situation, the migration rate at area A can be applied to
area B and modified for various considerations. Assuming an 8-year life is
desired, the starting width is 32 m. This width can probably be reduced, the
amount of reduction depending on the annual lateral activity level of the
active channels. Assume that the activity level is low. One might reduce the
number to 24 m in that situation. However, if the active channel does shift,
it will likely impinge on the bank at a relatively large angle, increasing
erosion potential. As a result, the width should be increased to 36 m instead
of decreased to 24 m. With relatively stable channels, the safety factor can
be about 1.5 to obtain a 54-m wide buffer.

Split Configuration. Rivers with split channel configurations are typ-
ically much more laterally stable than braided rivers. Thus, a historical
record of erosion rates for a split river is fairly reliable for projecting
future erosion rates. Channel alignment with respect to the buffer bank is an
important consideration, with larger erosion rates expected from channels with
larger angles to the bank. The factor of safety to apply to buffers on rivers
with split configurations may be as low as 1.2; the factor of safety would
increase with increasing channel activity and with decreasing confidence in
the buffer width estimate. See discussions of meandering and braided config-
urations for hypothetical examples of extending historical erosion rates.

Meandering Configuration. Rivers with meandering configurations typically
experience varying degrees of lateral migration, but the location and direc-
tion of migration is fairly predictable. A historical record of erosion rates
for a meandering system can be used to predict future erosion rates with a
high degree of reliability relative to previous configurations. Channel align-
ment with respect to an eroding bank tends to remain constant. The factor of
safety to apply to the width of buffers on rivers with meandering configura-

tions may be as low as 1.2 with a good data base; higher values should be used
as uncertainty increases in estimating the erosion rate.

The pattern of a meandering river and the expected zones of erosion are
illustrated in Figure A-7. Most meandering rivers deviate to some degree from

Figure A-7. Schematic of a meandering river showing the expected zones of
erosion as the river meanders migrate down the valley.

this pattern, but the basic principles are the same. Weandering rivers exhibit
a general tendency to migrate downvalley by eroding the cut bank on the out-
side of a bend from a point roughly midway through the bend and extending
generally to the beginning of the inside of the next bend downstream. The
gradual downvalley progression of the bends usually remains within a zone
called the meander belt drawn near the outside of each meander. The width of
the meander belt is usually constant for regular meander patterns. Irregular
meander patterns do not necessarily maintain a constant meander belt width,
but the erosion at the outside of bends is typical. The difference between a
regular meander pattern and an irregular meander pattern and the expected
zones of erosion associated with each is shown in Figure A-8. It is apparent

Regular Meander Pattern

Irregular Meander Pattern

Figure A-8. Schematics of regular and irregular meander patterns and
typical erosion zones.

from the location of the typical zones of erosion that the buffer width should
generally be greater on the outsides of meanders and the upstream side of the
insides of meanders.

As an example, consider the hypothetical river in Figure A-9 with a
regular meander pattern. A material site is proposed on an inside meander of a
small river, for which a buffer design life of 25 years is desired.

Figure A-9. Schematic of a river with a regular
meander pattern and a proposed location for a
mater ia I site.

The buffer surrounding the material site is separated into zones A and B
because they are zones of different expected erosion rates. Historical erosion
rates for zone A were 90 m between 1948 and 1978, or an average rate of 5 m
per year. In zone B, 270 m of deposition has taken place during the same
period. Starting with zone B, the bank opposite this zone should be inves-
tigated for any abnormality such as near-surface bedrock, which may stop the

erosion of this bank. If there is such an abnormality, the buffer width should
be increased from the standard minimum buffer width for the downstream end of
the site given in Section V A 5b. In this example, assume no abnormality
exists; use a standard minimum buffer width increased by 25 percent to account
for the increased design life (25 years instead of 20 years) to derive a 19 m
width in zone B. For zone A, an annual migration of 3 m per year over 25 years
would prescribe a 75-m wide buffer. No change in the average erosion rate is
expected from, for example, a meander cutoff developing upstream, and the
historical period is longer than the design life, thus, the user can feel
confident with the prediction. A safety factor of 1.2 can be used resulting in
a recommended buffer width of 90 m.

Sinuous Conf igurat ion. A river with a sinuous channel configuration is
expected to behave in a similar manner to that of the meandering rivers with a
few exceptions: erosion rates are often less in sinuous rivers than in mean-
dering rivers; and the erosion zone may extend farther upstream on the outside
of a sinuous river meander (Figure A-IO). Otherwise, similar procedures can be
used to estimate the recommended buffer zones. Safety factors as low as 1.2
can be applied to the buffers in zones of erosion on these relatively stable
rivers. See the discussion on meandering rivers for a hypothetical example of
estimating buffer sizes.

Straight Configuration. A river with a straight configuration will likely
have a similar erosion pattern to that of sinuous rivers, only less pro-
nounced. Straight rivers typically exhibit a sinuous pattern in their thalweg
with the inside meanders being formed by alternate bars or side channel bars.
Thus, what little bank erosion takes place in a straight river would occur
opposite and slightly downstream from these gravel bars, which may be sub-
merged under most flow conditions (Figure A-ll). Safety factors as low as 1.0
may be appropriate on straight rivers. The reason for the straight alignment
should be considered before evaluating the buffer requirements. For example,
if the straight reach resulted from meander cutoffs, a much larger buffer
would be required than if the straight reach is due to erosion resistant
banks.

Figure A-IO, Schematic of a sinuous river showing
typical erosion zones.

Other Buffer Width Factors

River Size. In general, erosion rates increase with increasing river
size. This increase is primarily due to the greater discharges associated with
larger river size. The increase is also due to the wider valley floors filled
with greater quantities of generally smaller sized alluvial sediments. The
rate of increase of erosion rates with river size is difficult to quantify. If
historical rates of lateral migration are available, river size does not have
to be considered separately.

Soi I Compos! t ion. The soil composition of the bank and buffer material is
Important to the erosion rate. Fine sands are generally the easiest to erode.

Figure A- 1 I . Schematic of a straight river
showing zones of potential erosion.

Larger sized granular material (such as coarse sands, gravels, cobbles) re-
quire higher velocities to be eroded because of the increased weight of the
particles. With vertical cut banks, large diameter materials often build up at
the base of the bank. This build up is because the finer materials holding
them in place are eroded away while the larger sized materials cannot be
transported. Material finer than fine sands (silts and clays) are often more
resistant because of the cohesion between particles.

If the buffer material is uniform throughout, then historical erosion
rates do not need to be modified for soil composition effects. If there are
areas of significantly finer or coarser sized materials, the historical ero-
sion rate should be modified accordingly based on the discussion in the pre-
ceeding paragraph.

Vegetat i ve Cover . Vegetation with deep root structures provides a resis-
tance to bank erosion. Dense ground cover on the buffer provides an increase
in the roughness of the buffer, causing a decrease in the velocity of flow
over the buffer. This, in turn, reduces the potential for erosion of the
buffer surface and the development of a channel through the buffer. This is a
primary reason why a buffer should not be disturbed.

When extending historical erosion rates, the vegetative pattern should
be considered. No compensation for vegetation is required if the vegetation is
comparable between the buffer and the area that eroded during the period of
historical erosion. If the vegetation type or density changes within the
buffer, or between the buffer and the area of historical erosion, then the
historical rate of erosion should be modified according to the type of change
and the discussion in the preceeding paragraph.

Permafrost Banks. The erosion of permafrost banks is a more complicated
process than unfrozen bank erosion. Various investigators have studied the
process; some have concluded that permafrost increases bank erosion, others
have decided that permafrost decreases bank erosion. Scott (1978) reviewed
previous investigations and added his own investigation of five rivers in
arctic Alaska. He concluded that the net effect of permafrost is to create
greater channel stability than is found in rivers of similar size in nonperma-
frost environments. However, banks which are ice-rich will likely have less
stability and higher erosion rates than other permafrost or nonpermaf rost
banks.

When using past records to predict future conditions, the thermal con-
dition of the banks should be considered. Past thermal conditions of the
banks are generally not known, consequently, it must be assumed that they were
similar to the current condition. If the banks are ice-rich, the safety factor
applied to the buffer width should be larger.

Channel Aufeis. Aufeis development in the active channel of a river can
cause a larger percentage of the snowme I t runoff to flow across the buffer
than otherwise would be expected. Doyle and Childers (1976) show a photograph

of this occurring at the Prospect Creek material site near the Trans-Alaska
Pipeline. This increased flow can cause erosion of the surface of the buffer,
especially any disturbed area. It can also cause scour or headcutting in the
material site because of the I arger-than-des i gn flows during breakup. The
safety factor applied to buffer width should be increased if channel aufeis is
known to develop at the site.

BUFFER HEIGHT

Buffer height and buffer width are interrelated to a certain degree.
If the buffer is high enough to keep all but the largest of floods out of
the material site, only bank erosion needs to be considered in buffer design.
This may be the situation for many material sites located on terraces. If the
buffer is low and is flooded frequently by larger flows, erosion of the sur-
face of the buffer, headward erosion of the upstream face of the material
site, and scour within the site must be considered in the buffer design. The
height of natural buffers is fixed at the level provided by nature. Design
options include increasing buffer width to account for low height, building up
the buffer height by adding a dike on the river side, or building a completely
separate buffer structure. These options are discussed in more detail in a
subsequent paragraph.

To evaluate the frequency of flooding, hydrologic and hydraulic analyses
must be carried out. The details of these analyses are too complex to explain
here, but appropriate references are given to allow the user to study the
subject further.

• A hydraulic analysis is required to evaluate what discharge will ini-
tiate overtopping of the buffer. Cross sections of the river, extending
up to the level of the buffer on both banks, are necessary for this
analysis. It is preferable to have five or more cross sections through
the reach of river adjacent to the buffer. The Manning equation or,
perferably, a backwater program, should be used to calculate the dis-
charge corresponding to the stage that would overtop the buffer. Discus-
sions of these analyses are provided in most open-channel hydraulics

textbooks (Chow 1959), and in other references (Bovee and Milhous 1978;
U. S. Army Corps of Engineers 1976).

• A flood frequency analysis provides an estimate of the recurrence
interval or probability of exceedance of the discharge which just
overtops the buffer. Detailed discussion of flood frequency analyses
are included in most hydrology textbooks, U. S. Water Resources Council
(1977), and Lamke (1979). Lamke (1979) provides equations for deter-
mining flood discharges for rivers in Alaska for the following recur-
rence intervals and corresponding exceedance probabilities:

Recurrence interval Exceedance probability
(years) (%)

I . 25 80

2 50

5 20

10 10

25 4

50 2

100

With the discharge and its frequency of occurrence known, the probability
of that flood occurring over the design life of the buffer is needed. Table
A- I below provides the probability of occurrence of a flood of a specified
recurrence interval during a specified buffer design life.

100

Table A-l. Probability of Occurrence (%) of a Specified Flood During

a Specified Design Life

Flood Buffer design life

( years)

Recurrence Exceedance
interval probab i I i ty
(years) (%) 2 5 8 10 20 25 50 100

1 .

99+

99-

100

99+ 99+ 99+ 99+ 99+ 99+ 99+

99+ 99+ 99+ 99+ 99+ 99+

89 99 99+ 99+ 99+

65 88 95 99 99+

54 56 64 87 98

18 55 40 64 87

10 18 22 59 65

a ^ J „ ^ ^..-^ Design Life

Probability of Occurrence = I - (I - Exceedance Probability)

With the known probability of flow through the site during the design
life of the buffer, the user can evaluate the consequences. If the probability
is low, the width of the buffer can be designed based on lateral migration
alone. If the probability is high, one of several design options are recom-
mended.

• If the buffer is heavily vegetated, and if flow through the material
site is acceptable, riprap the upstream edge of the material site
to prevent headward erosion; or, increase the width of the buffer to
allow for erosion loss (Figure A- 1 2a).

a . Heavily vegetated buffer and flow through
the site is acceptable.

b . Heavily vegetated buffer and flow through
the site is unacceptable.

c. Lightly vegetated buffer and flow through d. Highwater or abandoned channel through

site is acceptable. heavily vegetated buffer and flow through

site Is acceptable.

Figure A-12. Schematic of recommended options if the probability of flow
through the site is high.

102

• If the buffer Is heavily vegetated, and flow through the site is unac-
ceptable, construct a dike surrounding the material site designed

for a flood with an acceptably low probability of occurrence (Figure
A- 1 2b).

• If the buffer is lightly vegetated, build a dike along the river side
of the buffer designed for a flood with an acceptably low probability
of occurrence (Figure A-I2c).

• If the buffer contains a high-water or abandoned channel, build a
dike along the river side of the buffer to keep flow out of the chan-
nel; the dike should be designed for a flood with an acceptably low
probability of occurrence (Figure A-I2d).

As an example of buffer height design, consider the material site loca-
tion shown in Figure A-15. The buffer width has been estimated by historical

Cross
Section 5

Cross Section 6

Buffer Width
200 m

^ y /Pit

Material
Site

Cross Section 7-

Figure A-13. Schematic of an example of buffer height design.

103

erosion techniques. Cross sections are surveyed as shown (two additional
cross sections were collected further downstream). A backwater analysis was
run to find that discharges of 103 m /s and 89 m /s overflowed the buffer at
Cross Sections 3 and 7, respectively. A flood frequency analysis indicated
that these discharges had recurrence intervals of 35 and 25 years. The design
life of the buffer is 25 years. Thus, from Table A-l, at Cross Section 7 there
is a 64 percent chance of getting flow into the downstream end of the material
site within the 25-year life. This chance is acceptable to the user because
the flow would primarily be backwater and would have relatively low erosion
potential. At Cross Section 3 the upstream buffer has a 50 to 60 percent
chance of overtopping the buffer. The user finds this to be unacceptable, but
since there is a relatively small chance of substantial flow entering the pit
from the upstream side, he recommends riprapping the upstream bank of the pit.

REFERENCES

Bovee, K. 0., and R. T. Milhous. 1978. Hydraulic Simulation in Instream Flow
Studies: Theory and Techniques. Instream Flow Information Paper No.
5. Cooperative Instream Flow Service Group. Fish and Wildlife Service.
Fort Collins, Colorado. 125 pp.

Br ice, J. 1971. Measurement of Lateral Erosion at Proposed River Crossing
Sites of the Alaska Pipeline. U.S. Geological Survey. Water Resources
Division. Alaska District. 39 pp.

Chow, V. T. 1959. Open-Channel Hydraulics. McGraw-Hill Book Company, New
York. 680 pp.

Doyle, P. F., and J. M. Childers. 1976. Channel Erosion Surveys Along TAPS
Route, Alaska, 1976. Open-File Repor t-77-l 70 (Basic Data). U.S. Geolog-
ical Survey. Anchorage, Alaska. 90 pp.

Lamke, R. 0. 1979. Flood Characteristics of Alaskan Streams. Water Resources
Investigations 78-129. U.S. Geological Survey. Anchorage, Alaska. 61 pp.

104

Scott, K. M. 1978. Effects of Permafrost on Stream Channel Behavior in
Arctic Alaska. Professional Paper 1068. U.S. Geological Survey. U.S.
Government Printing Office, Washington. 19 pp.

U. S. Army Corps of Engineers. 1976. HEC-2 Water Surface Profiles: Users

Manual. Computer Program 723-X6-L202A. The Hydrologic Engineering Center.
Davis, California. 17 pp. + Appendix.

U. S. Water Resources Council. 1977. Guidelines for Determining Flood Flow
Frequency. Bulletin No. I 7A of the Hydrology Committee. Washington.
26 pp. + 14 Appendix.

105

APPENDIX B

FIELD INSPECTION: DESIRABLE DATA,
PROCEDURES, AND EQUIPMENT

APPLICANT SITE PLANNING FIELD INSPECTION

As part of the site planning process the applicant is recommended to
visit the proposed site or alternate sites, or both, during the open-water
season to gather the following information:

A. Technical data to substantiate aerial photographic interpretation
(e.g., sufficient quantity and quality of material, and percent

f i nes ) .

B. General site specific biological data regarding the presence of areas
or species of special concern that may be directly influenced should
site development occur.

C. Site specific hydraulic data relevant to site planning and agency
review (e.g., discharge, stage, and cross sections).

D. Ground photographs of site physical and biological characteristics
which will be used in support of work plan development and submittal
to appropriate agencies.

E. If a snow-covered site will be opened, all work area locations should
be surveyed during the open-water site visit. This survey should be
from reference locations that can be located during site opening.
Boundaries, such as those of active channels, buffer locations, vege-
tated areas, and gravel deposits, can then be accurately relocated
during site preparation. This will reduce the potential for damage to
areas that should not be disturbed.

107

F. If winter active-channel mining is contemplated, an adaitional site
visit during winter should be conducted. Its purpose is to determine
the presence of water at or below the proposed site.

Field Approach

Material Availability. A variety of techniques are available to evaluate
grandular materials present at a site. These include borings, test pits, and
resistivity measurements.

Biological Evaluation. The entire site should be walked (during which
time ground photos should be obtained) to subjectively assess the overall fish
and wildlife habitat quality in sufficient detail to make Decisions I through
4 in Section I B. It may be appropriate to make this a combined applicant-
agency site visit.

Hydraulic Data. Cross Sections: Cross sections of the river channel (s)
and floodplain should be surveyed to provide input to the hydraulic analysis
and the level to which excavation can extend. The number, location, and length
of the cross sections should be based on the following criteria (Figure B-l):

• There should generally be at least five cross sections; three or more
would generally be necessary to describe the site and one or more would
be required upstream and downstream from the site.

• Cross sections through the site should be located at the upstream and
downstream ends as well as one or more in between to define the extent
of mi n i ng.

• In addition to the locations necessary to define the site, cross sec-
tions should be located at each significant change in floodplain width.

• The upstream and downstream cross sections should be located at least
two active channel-top widths from the upper and lower limits of the
material sites and associated buffers.

108

TBM1

TBM2

TBM3

TBM4

LEGEND

n Temporary
^. Bench Mark
CP Cross Section
Number

TBM5

TBM 6

TBM7

aterial
Site

Thalweg

Profile

Alignment

Figure B- I . Schematic showing cross section number and locations,
temporary bench marks and thalweg profile at a hypothetical material
s i te.

109

• The length of the cross sections should include the entire active
floodplain width and should continue to an elevation on both ends
equivalent to at least the highest point in the material site or the
buffer, whichever is greater.

• Cross sections should be aligned perpendicular to the direction of flow
during flood events.

• The distances between and direction of the cross sections should also
be surveyed.

The surveys should be performed using standard surveying techniques. A descrip-
tion of these techniques and the desired accuracy is given in Bovee and
Mi Ihous ( 1978) .

Temporary Bench Marks: Temporary bench marks (TBMs) should be placed at
one end of each of the cross sections and one near the active channel where
the discharge measurements are taken (Figure B- I ) . The TBM elevations should
be tied into a common datum (often arbitrary datum at the upstream cross
section) as described in Bovee and Mi Ihous (1978).

Stage and Discharge: The stage (water surface elevation) should be re-
corded at the time the discharge measurements are taken. Discharge measure-
ments should not be taken while the discharge is rapidly changing. Discharge
measurements should be taken at a cross section in a relatively uniform chan-
nel reach; that is, the water surface slope and bottom slope should be similar
and the depth, area, velocity, and discharge should not change significantly
through the reach. Discharge measurements are taken by measuring the total
depth and the velocity at specified depths at 25 to 30 stations across the
ctiannel. The station (distance from a TBM) should also be recorded. Velocity
measurements should be taken at the following recommended depths below the
water surface relative to the total depth (d):

- 0.2d, 0.6d, and 0.8d is most preferred

- 0.2d and 0.8d is next most preferred

- 0.6d is recommended only if the depth (d) is less than 0.75 m

If the discharge is changing rapidly and the measurements must be taken at

that time, the 0.6d method should be used to complete the measurements faster.

Additional details on discharge measurements can be found in Bovee and Milhous
(1978) or Buchanan and Somers (1969).

Bed Material Size Distribution: The size distribution of the surface
layer of bed material is required for evaluating the hydraulic roughness of
the channel and floodplain. These data are obtained by an analysis of photo-
graphs using a grid-by-number technique as described by Kellerhals and Bray
(1971) or Adams (1979). The photographs should be tal<en, vertically downward,
of at least a I m square area of undisturbed surface layer gravels. A scale
should be included in the photograph.

Thalweg Profile: A thalweg profile should be surveyed of the channel bed
at those sites where the material site is being proposed on a gravel bar
adjacent to the channel or in the channel itself (Figure B- I ) . These data are
needed in the determination of the maximum depth to which gravel can be ex-
tracted. The profile should extend at least five channel widths beyond the
ends of the mined site.

Photographs. Photographs should be taken to show the main habitat fea-
tures of the river reach being studied (e.g., riffles, runs, pools, islands,
gravel bars, riparian shrub thickets, mud flats, backwater areas, incised and
undercut banks). If possible, photographs should be taken from an elevated
vantage point, such as a high bank. A sequence covering the entire reach of
stream is desirable. A record should be made of each photograph, including
date, time, location, direction of photograph, sequence, and main features
being photographed. If the visit is a follow-up to a previous field visit,
photographs identical to those obtained previously should be taken, as well as
those showing new features. If a winter visit occurs, photograph aufeis and
river ice characteristics.

AGENCY FIELD INSPECTION

The initial agency field inspection is recommended to verify the data
supplied by the applicant and to gather additional environmental data at
the site to identify the significant biological habitats. With this informa-
tion, any appropriate work plan that minimize environmental impacts can be
recommended. The field inspection should evaluate the overall habitat quality
and include observations on site-specific parameters including:

• General configuration of the river.

• Channel top width (size of river).

• Stage and discharge.

• Mean ve I oc i t y .

• Bank and instream cover.

• Substrate.

• Pool :riffle ratio.

• Presence of sensitive areas (i.e., spawning and overwintering areas).

• Dominant terrestrial habitats.

Desirable field inspection equipment for this site visit includes:

• Devices to measure water depth and top width.

• Device to measure water velocity.

• Data sheets of field book for recording field observations.

• 35 mm camera with color slide or print film.

• Dip net .

• Binoculars.

During the initial field visit a site sketch should be prepared perferably
using a copy of the aerial photo supplied with the work plan. This sketch
should identify major aquatic and terrestrial habitat locations and configura-
tions in relation to the boundaries and configuration of the work area, and
locations of special features such as settling basins, stockpiles, access
points, and others.

112

Subsequent agency visits (during site operation and site closure) should
measure the same parameters and document habitat alterations.

Field Techniques

Observations. Record and numerate all fish and wildlife encountered in
each habitat type.

Stream Velocity. Stream velocity can be estimated by placing a biodegrad-
able object with a density slightly less then that of water (such as an orange
or lemon), in the river and recording the time required to travel between two
measured points. Express the measurement in feet or meters per second.

Bank and Instream Cover. Bank and instream cover can be expressed as
percent of total cover and percent by each category. Categories for which
available habitat should be assessed include:

• Banks - undercut bank, overhanging bank vegetation, and near-surface
(submerged and emergent) bank vegetation.

• Instream - boulders, logs, large debris, and other velocity bar-
r iers.

• Depth - water depth acting as cover such as deep pools and runs.

Substrate. Estimate the percent of substrate composed of the different
particle sizes according to the modified Wentworth scale supplied in Appendix
H. Separate by pool and riffle.

Photographs. Photographs should be obtained to show the main habitat
features of the river reach being studied (e.g., riffles, runs, pools,
islands, gravel bars, riparian shrub thickets, mud flats, backwater areas,
incised and undercut banks). If possible, photographs should be collected from
an elevated vantage point, such as a high bank. A sequence covering the entire
reach of stream is desirable. A record should be made of each photograph.

I 13

including date, time, location, direction of photograpti, sequence, and main
features. Photographs identical to those obtained previously should be taken,
as well as those showing new features if the visit is a follow-up to a pre-
V i ous field visit.

Riparian Zones. These areas provide primary feeding, nesting, and cover
habitat for passerines and small and medium sized mammals. During winter
they also provide primary overwintering habitat for moose and ptarmigan.
Areas that consist of advanced or mature sera! stages, generally have well-
developed ground cover, shrub layer or overstory cover, or both, (in Northern
and Southern Interior regions) that provide desirable habitat. Sites that
contain riparian zones with high diversity of cover types (herbaceous marsh,
mature shrub thickets, mixed shrub thicket-early overstory forest and over-
story forest) may be considered more desirable than sites containing riparian
zones of homogeneous cover types. Watch for indicators of past activity
levels: old passerine nests, small mammal runways and burrows, red squirrel
feeding posts, moose browse, and moose and ptarmigan droppings in over-
wintering areas.

Water Bird Habitat. Feeding, nesting, and cover habitat for waterfowl,
shorebirds, terns, and gulls should also be assessed. Determine availability
of, and if possible utilization level of:

• Backwater areas, mud flats, and littoral areas as feeding habitat by
shorebirds, terns, and waterfowl.

• Pools and side-channels as feeding habitat by terns, gulls, and water-
fowl.

• Open and sparsely vegetated gravel bars as nesting habitat by gulls,
terns, and shorebirds (most frequently, semipalmated plovers, ruddy
turnstones, spotted sandpipers).

• Herbaceous riparian zones as nesting habitat by waterfowl and shore-
b irds.

114

Sites with a diversity of water bird habitats are more desirable than
sites with only one or two types present.

REFERENCES

Adams, J. 1979. Gravel size analysis from photographs, pp. 1247-1255. In

ASCE, J. Hydraulics Div. Proc. Paper 14908, Vol. 105, No. HYIO, October.

Bovee, K. D., and R. T. Milhous. 1978. Hydraulic Simulation in Instream Flow
Studies: Theory and Techniques. Instream Flow Information Paper No. 5.
Cooperative Instream Flow Service Group, Fish and Wildlife Service, Fort
Collins, Colorado. 125 pp.

Buchanan, T. J., and W. P. Somers. 1969. Discharge Measurements at Gaging
Stations, 65 pp. In Techniques of Water-Resources Investigations of the
U.S. Geological Survey, Book 3, Applications of Hydraulics. U. S. Govern-
ment Printing Office, Washington, D. C.

Kellerhals, R., and D. I. Bray. 1971. Sampling procedures for coarse fluvial
sediments, pp. I 165-1 180. _l_n ASCE, J. Hydraulics Div. Proc. Paper 8279,
Vol . 97, No. HYB, August.

APPENDIX C

RIVER-TRAINING STRUCTURES AND

BANK PROTECTION DEVICES ;

INTRODUCTION

River-training structures and bank protection devices may be required
during gravel removal operations or site closure, or both. Their purposes can
include protection of the site from flow during operation or after closure
and reduction of the potential for downstream siltation. River-training
structures also may be used to protect the bank of a buffer from excessive
erosion. River-training structures and bank protection devices generally
should not be used unless absolutely necessary because they usually disrupt
natural river processes, often resulting in scour and erosion elsewhere in
the system. In addition, bank protection devices can alter banks and their
adjacent riparian zones.

Revetments constitute the major group bank protection devices. River-
training structures in gravel removal operations primarly consist of dikes;
other types of these structures include retards, guide banks, spurs, and
jetties. Several publications are available that discuss the design of such
structures; these include California Division of Highways {I960); Karaki et
al. (1974); Neil I (1973); U.S. Army Corps of Engineers (1970) and Winkley
(1971). The following paragraphs discuss briefly dikes and revetments.

DIKES

Dikes are long embankments used to control the overflow of water into
the material site. Dikes may be constructed along an active channel or across
a high-water channel, or both. Dikes may also be used to block active side
channels in those cases where the bed is to be scraped. For these purposes,
the dikes should be impermeable, high enough to prevent overtopping, and
protected from erosion. Impermeable dikes are often constructed of stone or
earth, or both.

I 17

The design of dikes should include consideration of the following
(Figure C- I ) .

Continue ends of
dike beyond flood
Tlimits

Riprap
2:1 Slopes

^ Design Flow

Low Summer
Flow — 1

Low- Flow Buffer

SECTION A-A

Figure C-l. Dike design considerations.

• Side slopes should be stable and riprapped to withstand the flood for
which they are being designed (generally 2:1 slope is recommended; see
revetment design discussion).

• Top width is controlled by the requirements of the equipment con-
structing the dike.

• The ends of the dike should be located and designed to keep water from
flowing around them.

• The top of the dike should be at an elevation equal to that of the
water surface of the design flow; this water surface profile should be
determined using a hydraulic backwater analysis.

• Dikes should be built beyond the limits of the low-flow buffer.

BANK PROTECTION BY REVETMENTS

A revetment is a layer of erosion resistant material placed on a bank
or embankment to armor against erosion. Methods and materials for revetments
other than riprap are available but are not discussed here because they
generally are unacceptable for environmental reasons.

Riprap

The most common form of revetment is riprap, a layer of rock which
may be dumped, hand-placed, or grouted. Dumped rock riprap is most commonly
used, although grouted rock riprap may be applicable if the available ma-
terial is not large enough to meet the requirements of dumped riprap. Rock-
filled wire baskets (gabions) may also be used when available materials are
of insufficient size to meet dumped riprap requirements. There are several
factors important in the design of dumped rock riprap; these include:

• Shape, size, and gradation of the rock.

• Density and durability of the rock.

• Velocity and depth of flow near the rock.

• Steepness of the slope being protected.

• Thickness of the riprap layer.

• Filter blanket presence and design.

• End and toe protection.

These factors are discussed briefly in the following sections.

Shape, Size, and Gradation. The shape, size, and gradation of the rock
riprap are the primary properties in resisting erosion. The shape should be
angular to provide an interlocking of the rocks. Large rock is more erosion
resistant than small rock. Selection of the proper rock size is a complex
function of flow characteristics and slope of the embankment being protected.
Karaki et al. (1974) present a method for estimating rock size. Nei I I (1973)

presents a graph to use as a guide in selecting riprap size (Figure C-2).

ai
z
o

z
<

o
o

— 6'

z''

-.'

'b)

.•^

1
/

y
^

^
y

^
X

'/y

i^.

f— ^

0 100 300 500 700 900 1100

EQUIVALANT SPHERICAL DIAMETER OF
STONE I mm)

CURVE

SPECIFIED
STONE SIZE
%PINER

D33

^50
D40
D65

Ocallf.Hgws.

©Bur Public Rds

©Bur of Reclamn.

©Corps of Engrs

Assumed stone specific gravity = 2.65

BANK SLOPE

2 1

2.1

not given
not given
horizontal to 2 1

Figure C-2. Graph of riprap size vs. local flow velocity
(modified from Neill 1973).

It should be used with caution because not all aspects are incorporated.
Well-graded material improves the interlocking of the rock and reduces spaces
between rocks. A recommended gradation is shown in Figure C-3.

Density and Durability. The rock used for riprap should be hard, dense,
and durable to withstand cycles of wetting and drying, and freezing and
thawing. These cycles can cause cracking of the rock, resulting in reduction
of size and erosion resistance. Density and durability are generally deter-
mined by laboratory tests.

120

0)
c ^

c a;
a3 >.

100-
90-

80-
70-
60
50
40
30
20
10
0

Dcn= Median Riprap Diameter

■'50

0.1 D.

0.5D,
Sieve Size

'50

-"50

2C^

Figure C-3. Suggested gradation for riprap (after Karaki et al. 1974)

Velocity and Deptti of Flow. A primary factor influencing erosion is
ttie local velocity of ttie flow. Direct flow measurements are recommended,
but these may be difficult to obtain during flood events. In the absence
of measured data, Neil I (1973) reconmends the local velocity against a slope
be taken as:

• Two thirds of the average velocity in straight reaches.

• Four thirds of the average velocity in severe bends.

The shear stress on the rock riprap is proportional to the depth of flow
above the riprap. Thus the rock size should increase with increasing depth.

Steepness of Slope. The stability of riprap revetment decreases with
increasing steepness of slope. The steepest slope on which riprap will rest
without flow forces is the angle of repose of the material, which is gen-
erally between 35 and 45 degrees. Flow against the rock will decrease the
angle of stability. It is recommended that slopes of 2:1 (2 horizontal to I
vertical) be used. Slopes steeper than 1,5:1 generally should not be used.

121

Thickness of Riprap. The thickness of the riprap should be sufficient
to provide the desired protection of the slope. The minimum thickness should
be equal to the longest dimension of the largest rock or be 50 percent larger
than the median rock size, whichever is larger. This minimum thickness should
be increased by 50 percent if:

• Wave action is possible.

• Gradation is not as recommended.

• Riprap is to be placed in flowing water.

• A filter is not used when recommended.

Filter Blankets. A filter blanket may be recommended for placement
beneath the rock riprap layer to prevent the loss of bank material through
the voids in the riprap. If the material washes out, cavities will form
beneath the riprap and failure of the riprap revetment can occur. The require-
ments for a filter depend on the size and gradation of the bank material and
on the voids in the riprap layer. If the composition of the bank material is
such that it is easily eroded, a filter layer is generally recommended.
Poor riprap gradation is also a reason to recommend a filter. Filters may
be well-graded gravel or a synthetic filter cloth.

Gravel filters should use gravels ranging from about 5 mm to 90 mm
(Karaki et al. 1974). Filter thickness should be no less than 0.15 m; filter
thickness equal to half the riprap thickness is recommended. More than one
layer, of different gradation and median size, should be considered if there
is a very large difference in size between the bank material and the riprap
rock. Recommended guidelines for gradation of the filter are given by Karaki
et al. (1974); they are summarized in relations below.

These relations should be applied to each layer in turn, starting with
the bank material as the fine material and using the needed filter material
as the coarse. The first filter selected then becomes the fine material for
the next filter layer computation. After determining the size and gradation
of each filter, these relations should be used with the last selected filter

122

as the fine material and the riprap as the coarse material. If the results
are within the indicated limits, an additional filter layer is not needed.

D-. (coarse)
50

D^^ (fine)
50

< 40

D,^ (coarse) .^
5 15 < 40

D.^ (fine)
I 5

D,^ (coarse)
15 < 5

D (fine)

Where D is median diameter, D is the diameter particle of which 15 per-
cent of the material is finer, and D is the diameter particle of which
85 percent of the material is finer. An example of filter gradation design
is given in Figure C-4.

Filter cloths have been used with success for more than a decade. They
can support large riprap material with no damage to the cloth. A disadvan-
tage of filter cloths is that the riprap must be placed with care to prevent
damage to the cloth.

End and Toe Protection. The ends of the riprap revetment along the
channel may be subject to erosion. The erosion could remove material from
behind the riprap and cause failure of the riprap. Extending the riprap
revetment to areas not having erosive velocities is a recommended end protec-
tion (Figure C-5a). If this is not possible, the thickness of the riprap
layer should be increased to twice that otherwise needed. This extra thick-
ness should be placed in a recess cut into the bank to maintain a uniform
riprap face (Figure C-5b).

123

GIVEN:

Riprap
Filter 2
Filter 1
Embankment

EMBANKMENT

RIP-RAP

Di5(mm)
D5o(mm)
D85(mm)

0.10
0.20
0.50

300
500
800

STEP 1: FILTER 1 GRADATION DESIGN

D5o(FiLTER 1 ) < 40 X D50 (EMBANKMENT) = 8mm

0.5mm = 5x Di5(EMBANKMENT) < D,5(FILTER1) <40 x Di5{EMBANKMENT) = 4mm

Di5(FILTER 1) < 5 X Das (EMBANKMENT) = 2.5mm
SELECT Di5 = 1 .5mm, D50 = 3.0mm, Dgs - 6.0mm

STEP 2: FILTER 2 GRADATION DESIGN

D5o(FILTER 2) <40 x D5o(FILTER 1) = 120mm
7.5mm = 5xDi5(FILTER1) < D,5(FILTER2) <40x D,5(FILTER 1) = 60mm

D,5(FILTER 2) <5 x D85(FILTER 1) = 30mm
SELECT Di5 = 20mm, D50 = 40mm, Dgs = 80mm

STEP 3: CHECK FILTER 2 DESIGN AGAINST RIP-RAP

DsolRIP-RAP) <40xD5o(FILTER2)

5xDi5(FILTER2)<
100mm <

500mm
Di5(RIP-RAP)

300mm
Di5(RIP-RAP)

300mm

< 1600mm ^ OK
<40xDi5(FILTER2)

< 800mm ^ OK
^5xD85(FILTER2)

< 400mm ^ OK

STEP 4: SUMMARY

ACCEPTABLE FILTER GRADATION DESIGN TABLE:

FILTER 1
Di5(mm) 1.5

D5o(mm) 3.0

D85(mm) 6.0

FILTER 2
20
40
80

Figure C-4. Example of filter gradation design.

124

Figure C-5. Schematic showing plan view of end protection configurations:
a) extension out of the zone of erosion with a potential reduction in thick-
ness, and b) increasing the thickness at the ends of the revetment.

The base of the riprap revetment can be undercut by scour of the bed
if the toe is not protected. Extending the riprap layer below the level
of the bed and backfilling is recommended (Figure C-6a). If this cannot
be done, the riprap layer should be continued on the channel bed with an
increased thickness to provide material to fill any scour holes that de-
velop, thus preventing the scour from undercutting the riprap (Figure C-6bl

125

Riprap

Backfill to Original
Bed

•Thickness Depends on Potential
for Scour

Figure C-6. Schematic showing cross section of toe protection configurations:
a) extension of the riprap below the dry bed and backfilling, and b) place-
ment of extra material along the bed to launch itself into developing scour
holes.

REFERENCES

California Division of Highways. I960. Bank and Shore Protection in

California Highway Practice. Sacramento: Documents Section, State of
Ca I i f or n i a .

Karaki, S., K. Mahmood, E. V. Richardson, D. B. Simons, and M. A. Stevens.
1974. Highways in the River Environment, Hydraulic and Environmental
Design Considerations. Prepared for the U. S. Federal Highway Adminis-
tration.

Neill, C. R., ed. 1975. Guide to Bridge Hydraulics. Published for Roads and
Transportation Association of Canada, by Univ. of Toronto Press. 191 pp.

U. S. Corps of Engineers. 1970. Hydraulic Design of Flood Control Channels,
Engineering and Design. Manual No. EM- I I 10-2- I 60 I .

Winkley, B. R. 1971. Practical Aspects of River Regulation and Control,

In: River Mechanics, Vol. I. Hsien Wen Shen, ed. , Prof, of Civil Eng.,
Colorado State University.

126

APPENDIX D
DESIGN OF PITS

There are two basic designs to consider when mining floodplain gravel by
pit excavation: pit not connected, or pit connected to an active channel. A
properly designed unconnected pit can provide waterfowl, shorebird, and amphib-
ious mammal habitat. If the pit is connected to the active channel, the pit
can also provide fish habitat. The outlet channel of the connected pit allows
fish that become trapped in the pit during high water to emigrate from the pit
at any time. If the pit is unconnected, it should be protected from the 20-
year flood. Fish trapped during these floods are considered lost from the
r i ver popu I at i on.

SHAPE AND DEPTH

The desired configuration for a gravel pit excavated in an inactive
floodplain or terrace is long and narrow, in the shape of a channel, with a
variety of depths (Figure D- I ) . If the pit is connected to the river or fish
are to be stocked in the pit, the mean depth should be greater than 2.5 m to
allow fish survival during winter. For a pit with a configuration as shown in
Figure D- I , the following are two examples of depth regimes that will result
in a mean depth of 2.5 m:

A. For a minimum mean depth with a minimum of littoral area

Mean of depth Percent of

interva I (m) pit area

25
10
10
50
5

AAaximum depth: 5 m
Mean depth: 2.5 m

127

"iiJ^^r^ ■•wfl^'^

c
c

o
>

T3
0)

U
0)

c
c
o
o

<u
>

c
O

c
«

128

B. For a minimum mean depth with a maximum littoral area

Mean of depth Percent of

interval (m) pit area

0.5 35

1.5 10

2.5 10

3.5 15

4.5 25

5.5 5

Maximum depth: 6.0 m
Mean depth: 2.5 m

A pit with greater littoral area generally allows greater productivity
and is preferred for waterfowl, shorebirds, and fish. In both of the above
examples an increased mean depth will decrease the probability of fish winter
mortality. If more gravel is required, increasing depth is preferred over
increasing the surface area of disturbance.

METHOD FOR CALCULATING MEAN DEPTH OF P I T

To obtain an estimate of the mean depth of a designed pit, the following
procedures can be used.

A. Determine the l-m (or other unit of measure) contour intervals for the
pit.

B. Determine the percent of surface area(s) consisting of a particular
l-m depth interval [i.e., 0-1 = 0.35;
where n = number of depth intervals],

l-m depth interval [i.e., 0-1 = 0.35; 1-2 = 0.10; ;(n-l)-n = s ,

129

C. Multiply the midpoint of each l-m depth interval (d) by the percentage
of area composed of that interval [(i.e., d x s = (0.5) (0.35); (1.5)
(0. 10) ,. .. , (d ) (s ) ].

0. Wean depth = sum of all products in C. [i.e., mean depth = r ds =

(0.5)(0.55) + (I.5)(0.I0) + ... + (d )(S ].

n n

The Table below contains example calculations of mean depth of the pit
shown in Figure D-l. The letters refer to the four steps listed above.

Contour
i nter va I
(m)

Surface area

( ha or
other unit)

(%)

Wi dpoi nt

of contour

i nterva I

(m)

Product of
midpoint and
percentage area

(m)

0-1
1-2
2-3
3-4
4-5

Total

1.28

0.5

0.64

1.5

0.52

2.5

1 .08

3.5

0.30

4.5

3.82

100

0. 17
0.26
0.35
0.98
0.36

2.12= mean depth

130

APPENDIX E

FISH PASSAGE STRUCTURES

PROVIDING FOR FISH PASSAGE OR CULVERT GUIDELINES

Fish passage structures should be provided when it is necessary to cross
drainages. Bridges are preferable for fish passage; however, they are often
economically unfeasible because of the short projtct life and remoteness of
most floodptain gravel removal operations. If mature timber is available,
it may be used for effective and economical log culverts. Metal culverts,
although generally undesireable in temporary roads, are usually utilized, but
must be installed properly to provide adequate fish passage. The following
guidelines on fish passage structures are a synopsis of those developed by
Dryden and Stein (1975) and U. S. Department of Agriculture (1979) for the
protection of fish resources. The former document presents guidelines to be
considered in Northwest Territories road design while the latter deals specif-
ically with how to properly design fish passage structures in Alaska roadway
drainages. Refer to these documents for more detail and specifics.

Hydro logical Design

Structure Velocities.

A. In general, the average velocity should not exceed 0.9 m/s during fish
migration periods. Many species require velocities considerably less
than this during migration periods and fish passage can be impeded at
velocities of 0.3 m/s (Figure E-l).

B. A 3-day delay period (3 days of velocities in excess of those required
for passage) should not be exceeded during the mean annual flood
(2.33-year recurrence interval flood). A 7-day delay period should not
be exceeded in the design flood.

151

WATER VELOCITY (cm/sec)

Figure E-l. The relationship between fish fork length and ability to move
100 m against water velocities of 0-80 cm/sec in 10 min. The same curves
may also be used to indicate the ability to make progress against these
currents over shorter distances. For instance, to cross a 50-m barrier in
10 min the curves should be shifted 8 cm/sec to the right; to cross a 25-m
barrier in 10 min the curves should be shifted 12 cm/sec to the right. The
line for char is derived from the hypothetical equation V = 17 L°*' and
represents the measured value in these experiments (from Jones 1975).

132

Minimum Water Level . The water level in the culvert should not be less
than 20 cm during the open-water season unless fish passage is not required.

Structure Design

Shape.

A. If suitable timber is available, native log stringer or rough-sawed
timber bridges and log culverts are the most desirable temporary
structures for the passage of fish. They maintain the natural stream
bed and gradient and are easy to remove.

B. Arch culverts with an open bottom are preferred culverts for permanent
roads. These culverts retain natural bed material. Closed arch cul-
verts are second in preference.

C. Horizontal ellipse culverts can maintain stream flow width and natural
bed material if the culvert invert is placed below the stream bed

e levat ion.

D. Circular culverts are impractical for fish passage unless installed
as described by U. S. Department of Agriculture (1979), summarized in
the following section.

Installation and Design.

A. Culvert inverts should be laid a minimum of 15 cm below normal stream
bed elevation. The Alaska State Pipeline Coordinator's Office often
recommends a burial depth of 20% of culvert diameter.

B. Inverts should be designed to prevent hydrostatic uplift at the down-
stream or upstream end.

C. The culvert gradient should be kept as close to 0% gradient as pos-
sible so that upstream or downstream velocity barriers are not
created.

133

Capacity. Culverts should tiave sufficient capacity to pass the design
flood with no backwatering or ponding at the upstream end.

Location.

A. Culverts should not be placed where a channel cutoff or diversion
will resu I t .

B. The culvert should be placed so that its discharge is not directed
at an unstable bank.

Multiple Culverts. A 1.8 m spacing should be present between adjacent
culvert walls. This will provide a downstream backwater area for fish to rest
in before attempting passage.

REFERENCES

Dryden, R. L., and J. N. Stein. 1975. Guidelines for the Protection of the
Fish Resources of the Northwest Territories During Highway Construction
and Operation: Environment Canada. Fisheries and Marine Service Tech.
Rept. SeriesNo. CEN/T-75-l. 52 pp.

Jones, D. R. 1975. An Evaluation of the Swimming Performance of Several Fish
Species from the MacKenzie River. Dept. Environment, Fisheries
and Marine Service, Winnipeg, Man. 53 pp.

U. S. Dept. of Agriculture. 1979. Roadway Drainage Guide for Installing

Culverts to Accommodate Fish. Engineering and Aviation Management Div-
ision, Forest Service. Alaska Region Report No. 42. 121 pp.

134

APPENDIX F

SETTLING PONDS AND WASTEWATER TREATMENT

WASTEWATER TREATMENT

The Federa I -St ate effluent guidelines indicate that total suspended
solids (TSS) is the main effluent parameter that must be monitored during
mining and processing of construction sand and gravel (Hall and Kosakowski
1976). The present EPA requirement is that the TSS of a gravel mining effluent
should not exceed 50 mg/Jl at any time. In order to accomplish this final
concentration, a series of settling ponds and often a coagulant are normally
required. Specific needs will vary according to the amount of washing neces-
sary and the soil characteristics of the material. In a washing operation,
wash water can usually be recycled without need for discharge. In this case
the amount of settling required will depend on the need of the operator for
clean water. Generally, recycled water with a TSS of less than 200 mg/e, is
suitable for reuse.

Specific details on how to design and operate settling ponds are dis-
cussed in Monroe (1973) and this document should be referenced if additional
information is needed. Following is a brief synopsis of his major recommenda-
t ions.

Settling Ponds - pond with an outlet

A. Used to clarify water for reuse or effluent discharge.

B. Cross-sectional area of the pond must be large so horizontal velocity
is very slow.

C. Water must enter pond over most of the width to make the entire pond
effective (e.g., to avoid short circuiting, channel formation).

D. The outlet must be wide to skim off the top clear water and maintain a
low horizontal velocity.

Filter Ponds - pond without an outlet

A. Used where there is no discharge or recirculation,

B. Water table must be low enough that water will filter out, not into
the pond. Pond berms must be high enough to guard against floods.

C. Walls and bottom of the pond must be porous to allow outflow. Ponds
seal more slowly if they are kept full so all the area of walls and
bottom are working.

D. Pond must be large enough so ii will not seal.

E. Coagulants should not be used in filter ponds because they shorten the
life of these ponds.

F. It is best to precede the filter pond with a settling pond for heavy
particle settlement.

Coagu lat ion

A. Used when there is a high concentration of solids that will not settle
or there is limited area for settling ponds, or both.

B. Must be thoroughly mixed to be efficient.

C. Works better in warm water; settlement rate is doubled for every
35 C increase in temperature.

D. Commonly used coagulants are: aluminum sulphate (alum), ferrous sul-
phate (copperas), calcium hydroxide (hydrated lime), calcium oxide
(quick lime), sodium aluminate, sodium carbonate (soda ash), ferric
chloride (ferrisul), sodium silicate.

136

E. Multipond arrangement may be most suitable.

F. Coagulant should be added to the water at inlet to each pond.

REFERENCES

Hall, E. P., and M. W. Kosakowski. 1976. Mineral Mining and Processing

Industry. Development Document for Interim Final Effluent Limitations
Guidelines and Standards of Performance. Environmental Protection Agency,
Effluent Guidelines Division, Office of Water and Hazardous Materials.
Wash. , D. C. 452 pp.

Monroe, R. G. 1973. Wastewater Treatment Studies in Aggregate and Concrete
Production. Environmental Protection Technology Series EPA-R2-73-003.
Environmental Protection Agency, Office of Research and Monitoring,
Washington, D. C. 108 pp.

137

APPENDIX G

EFFECTS OF BLASTING ON AQUATIC ORGANISMS

Although infrequently required on floodplain sites, blasting may be
utilized during certain phases of gravel removal. Teleki and Chamberlain
(1978) developed a series of curves and equations to estimate the fatality
radius of a particular charge (based on an explosive with a detonation veloc-
ity of 4940-5490 m/s) in relation to certain types of fish (Figure G- I ) .

A number of studies have evaluated the effects of blasting on a particu-
lar organism or groups of organisms. Table G- I summarizes the results of some
of these studies and indicates the range of sensitivities shown by aquatic
organisms to pressure changes.

The force generated by a particular charge can be determined at various
distances by referring to Table G-2.

REFERENCES

Alpin, J. A. 1947. The effect of explosives on marine life. Calif. Fish and
Game 53( I ) : 23-27.

Baxter, R. E. 1971. Effects of Explosives Detonated in Ice on Northern Pike,
Kuskokwim River, 1970. Alaska Dept. Fish and Game Info. Leaflet 154.
18 pp.

Falk, M. R. , and M. J. Lawrence. 1973. Seismic Exploration: It's Nature and
Effect on Fish. Fish and Maine Service Central Region. Tech. Rept. Series
No. CEN/T 73-9.

Hanson, H. 1954. Fur seal control program, Copper River and Bering River
area. Alaska Dept. of Fisheries.

159

Hubbs, C. L., and A. B. Rechnitzer. 1952. Report on experiment designed to
determine effects of underwater explosions on fish life. Calif. Fish and
Game 38(5) : 333-566.

Rasmussen, B. 1967. The Effect of Underwater Explosions on Marine Life.
Bergen, Norway. 17 pp.

Teleki, G. C, and A. J. Chamberlain. 1978. Acute effects of underwater con-
struction blasting on fishes in Long Point Bay, Lake Erie. J. Fish Res.
Bd. Canada 35: I I9I-I 198.

U. S. Navy. 1970. U. S. Navy Diving Manual. NAVSHIPS 0994-001-9010.

140

Q
<
CC

T 1 1 1 1 1 1 1 1 1 1 1 1 [

280 20 100 200 280

120-1
100-
80-
60-
40-
20-

III

>95%

— 1 1 1 1 1 1 ! 1 1 1 1 1 1 1

20 100 200 280

—I — I — I — I — I — I — I — ! — I — I — r

20 100 200

MAXIMUM EXPLOSIVE WEIGHT PER CHARGE kg '

T 1

280

Figure G-l. Relationship of kil ogram per charge to fatality radii (FR):
A = 10-20% mortal ity, B = 95% mortal ity.

I = physoc I i St i c , high lateral compression (pumpkin seed, crappie, white
bass ) .
II = physoc I i st i c, moderate lateral compression (rock bass, smallmouth bass,

ye I I ow perch ) .
Ill, IV = physostomic, f us i form (IN = quillback, white sucker, yellow

bullhead; IV = rainbow trout) (from Teleki and Chamberlain 1978).

Equat ions (From Teleki and Chamberlain 1978)

I A: log FR = 1.2423 + 0.3340
IB: Log FR = 0.8814 + 0.3390

lA: Log FR = 1.3540 + 0.3337
IB: Log FR = 0.9087 + 0.3323

lA: Log FR = 0.9261 + 0.3344
IB: Log FR = 0.8199 + 0.3429

VA: Log FR = 0.8465 + 0.3382
VB: Log FR = 0.7297 + 0.3624

og kg
og kg

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143

APPENDIX H

STANDARD FORMULA AND CONVERSION FACTORS

CONTINUITY OF FLOW

^^ = V2

where 0 = discharge

A = cross sectional area of the flow at I

V = mean flow velocity at I

A = cross sectional area of the flow at 2

V = mean flow velocity at 2

VELOCITY OF CULVERT FLOW

Culvert Flowing Full (Outlet Control)

where V = mean flow velocity in culvert
0 = discharge through culvert
A = cross sectional area of culvert

Cross sectional areas of plate steel arch, pipe-arch, and circular culverts
of various sizes are listed in Tables H-l, H-2, and H-5. Estimates of cross
sectional areas of circular culverts whose inverts are buried below the stream
bed can be obtained from Tables H-l or H-2, using measured or estimated span
and r i se va I ues.

Culvert Flowing Partially Full (Inlet Control)

Outlet velocity may be approximated by computing the mean velocity for the
culvert cross section using Manning's equation. Manning's equation can be
wr i t ten :

145

Table H- I . Cross-Sectional Area of Plate Steel Arch Culverts

Span

ft- in

Rise

ft- in

Cross-Sectional Area
m" ft^

1.83

6-0

0.70

2-?.h

0.93

2.13

7-0

0.86

2-10

1.39

2.44

8-0

1.02

3-4

1.86

2.74

9-0

1.18

3-1 0^2

2.46

2655

3.05

10-0

1.35

4-5

3.16

3.35

11-0

1.36

4-5?s

3.44

3.66

12-0

1.52

5-0

4.18

3.96

13-0

1.55

5-1

4.55

4.27

14-0

1.70

5-7

5.39

4.57

15-0

2.01

6-7

6.97

4.88

16-0

2.16

7-1

7.99

5.18

17-0

2.18

7-2

8.55

5.49

18-0

2.34

7-8

9.66

104

5.79

19-0

2.49

8-2

10.96

118

6.10

20-0

2.53

8-3^5

11.52

124

6.40

21-0

2.69

8-10

13.01

140

6.71

22-0

2.72

8-11

13.56

146

7.01

23-0

3.00

9-10

15.89

171

7.32

24-0

3.15

10-4

17.47

188

7.62

25-0

3.31

10-lOis

19.23

207

7.62

25-0

3.81

12-6

22.95

247

146

Table H-2. Cross-Sectional Area of Pipe-Arch Culverts

Span

Rise

Cross-

-Sectional Area

ft- in

ft-in

ft^

0.46

1-6

0.28

0-11

0.10

1.1

0.63

2-1

0.41

1-4

0.20

2.2

0.91

3-0

0.56

1-10

0.41

4.4

1.27

4-2

0.79

2-7

0.81

8.7

1.47

4-10

0.91

3-0

1.06

11.4

1.65

5-5

1.02

3-4

1.33

14.3

1.85

6-1

1.40

4-7

2.04

2.13

7-0

1.55

5-1

2.60

2.41

7-11

1.70

5-7

3.25

2.69

8-10

1.85

6-1

3.99

2.97

9-9

2.01

6-7

4.83

3.25

10-8

2.11

6-11

5.39

3.53

11-7

2.26

7-5

6.22

3.81

12-6

2.41

7-11

7.25

4.09

13-5

2.57

8-5

8.27

4.34

14-3

2.72

8-11

9.38

101

4.67

15-4

2.82

9-3

10.13

109

5.00

16-5

3.02

9-11

11.71

126

5.03

16-6

3.35

11-0

13.29

143

5.31

17-5

3.51

11-6

14.68

158

5.66

18-7

3.66

12-0

16.17

174

5.94

19-6

3.81

12-7

17.65

190

6.27

20-7

4.01

13-2

19.88

214

147

Table H-3. Cross-Sectional Area of Circular Culverts

Inside Diameter

ft-in

Cross-sectional

area

tn^

ft^

0.074

0.8

0.17

1.8

0.29

3.1

0.49

5.3

0.66

7.1

0.89

9.6

1.17

12.6

1.48

15.9

1.82

19.6

2.63

28.3

3.58

38.5

4.67

50.3

5.91

63.6

7.29

78.5

8.83

95.0

10.51

113.1

12.33

132.7

14.30

153.9

16.42

176.7

18.68

201.1

21.09

227.0

23.64

254.5

26.34

283.5

29.19

314.2

0.30

1-0

0.46

1-6

0.61

2-0

0.76

2-6

0.91

3-0

1.07

3-6

1.22

4-0

1.37

4-6

1.52

5-0

1.83

6-0

2.13

7-0

2.44

8-0

2.74

9-0

3.05

10-0

3.35

11-0

3.66

12-0

3.96

13-0

4.27

14-0

4.57

15-0

4.88

16-0

5.18

17-0

5.49

18-0

5.79

19-0

6.10

20-0

148

n
where V = mean flow velocity in culvert (m/s)
n = Manning roughness coefficient
R = hydraulic radius (m)
S = slope of culvert invert (m/m)

Approximate values of roughness coefficient are listed below:

smooth lined culverts n = 0.012

corregated metal culverts n = 0.024

culverts part iaily filledwith grave Is and cobbles n = 0.036

Estimates of the hydraulic radius of culverts can be obtained from Figure
H-l. A nomograph for solving Manning's equation and an example problem are
given in Figure H-2.

DISCHARGE MEASUREMENTS

Standard Measurement Technique

The U. S. Geological Survey has developed a technique for measuring
the discharge in a river (Buchanan and Somers, 1969). A relatively straight
and uniform reach of river should be selected for taking discharge measure-
ments. The width of the channel (s) should be divided into a number of sub-
sections (25 or more are recommended) that are often, but do not have to
be, the same width (Figure H-3 ) . Velocities are measured at each of the ob-
servation points at one or more depths depending on the flow depth, desired
accuracy, and rate of change of the flow. Generally speaking, the accuracy
of the mean velocity increases with increasing number of current measurements
at one observation point. An exception to this is when the flow is changing
rapidly, thus requiring that the discharge measurements be completed in a
short time span. Equations for calculating mean velocity are given in Figure
H-3 for three common measurement techniques. Discharge in each subsection
is the product of the mean velocity in the subsection and the cross-sectional

149

Definition of hydraulic radius:
R = A

Where R = hydraulic radius

A = flow cross-sectional area
P = wetted perimeter

Approximate value of hydraulic radius for circular culverts:

Approximate value of hydraulic radius for arch culverts:

0.2 X Span

Span

Figure H-1 . Methods of estimating hydraulic radius of culverts.

150

^.3

15—

-so

149 Tm 1A
EQUATION V- n R^S*^

14—

- (English Units)

13—
12-

:40

—.2

'-- V=^R?^S^

11 —

^ 3 (Metric Units)

10-

—

.1-

r30

8—

-01

_10

L 4

■

I- 09

7 —

1 OS

L 5

6—

-20

: o7

L 06

Le ^

5 —

L 05

.2-

Lo4

4—

- 02

o Xo z

^03 1

L10 ^t^ ^

^P^
">-

I DC

;

^02 1

^ '-_

'■-z =

L03

: ^ 1

-7 a H

: 1

"- ^ \

^ 2-

w z

6 > UJ

-04

•- ^

\ '~' ~

; 1 o

:_ 009 ss

Ij- ^

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-5 >- E

[ ^

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~ H UJ

- 05

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1- 007 ^

L4 0 "

L006 g

\ ^

\^ -

\ i ^

L06

L 005 >

1 —

Example

"^N;

: > UJ

-3 Z

L 07

L. OD4 ^

: Given:

: I

i 08

::rr^o3

Invert Slope = 0.003
r* 2m dia. circular

O
O

L 09

'-- corrugated culvert,

L iO

i-5 partially lined

-2

L 002

Flow depth In culvert
^6 = 0.3m

5 —

-^ Find:

Lg Flow velocity

L 001

~^ Solution:

:_ 0009

_ OOOB
_ 0007

-10 Select roughness

-1.0

1 2

coefficient of 0.02

L.9

_ 0006

Connect slope and

L.8

roughness

1- 0005

-_ coefficient

2 —

L 7

L 3

L 0004

5-^

Estimate hydraulic

i. 6

^ 0003

6—

radius

-.45 dia. = 0.9m
^ -flow depth 0.3m

L.5

1 4

0.9m

Draw line from hydraulic radius thr<

3ugh

-R = 0.6 X flow

intersection of slope-roughness

coefficient

depth

line and turning line to the veloci

= 0.18m

scale to get V = 0.88m/s

Figure H-2. Nomograph for solution of IVIanning's equation.

151

b(n-l)

INITIAL
POINT

1,2,3, n

bi,b2,b3, bn

^1'^2'^3' ^n

EXPLANATION

Observation Points
Dtstance from the Initial

Point to the Observation Point
Depth of Water at the
Observation Point

where

COMPUTATIONS

Q=E ^i

i=1

_ f biti-bi-i"| ,
qi = V, [ — 5 Jdi

V: = V

*^'2d*^'8d^2v,^)/4

2d^%,'^2

V = mean velocity in section i

.6d

measured velocity at 0.2d below the water surface
= measured velocity at 0.6d below the water surface
measured velocity at 0.8d below the water surface

Figure H-5. Discharge measurement technique.

152

area of flow in the subsection. Total discharge in the channel is the sum
of the discharges in the subsections (Figure H-3).

Approximate Measurement Technique

The discharge in a channel can be approximated using simple field tech-
niques. The cross-sectional area of flow can be estimated for the entire
cross section as the product of the top width and the average depth. The
mean surface velocity in the channel can be estimated by placing an object
which just barely floats in the flow near the center of the channel and record-
ing the time required to travel between two measured points. The mean velocity
is typically 80 to 90 percent of the surface velocity. The product of the
estimated mean velocity and cross-sectional area is the estimated discharge.

REFERENCE

Buchanan, T. J., and Somers, W. P. 1969. Discharge measurements at gaging
stations. Chap. A8, Book 3, Techniques of Water-Resource Investigations
of the United States Geological Survey, U. S. Government Printing Office,
Washington, D. C. 65 pp.

153

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154

Table H-5. Conversion Factors

Length

Area

Vo I ume
Speed

To convert

mm
mm
cm
cm

^ 2

m/s

Vo I ume flowrate m/s

Mass
Force

Pressure

Temperature

Concentrat i on

kPa

i nto

inches

feet

i nches

feet

yards

mi I es

square feet

square yards

acres

square mile

cubic yards

feet per second

cubic feet per

second

pound-mass

pound-force

K i logram-f orce

pound-force per

Mu 1 1 i p I y by

0.03937
3.281 X 10
0.3937
3.281 X 10
3.28 1
I .094
0.6214
10.76
I . 196
2.471
0.3861
I .308
3.28 1

35.31
2.205
0.2248
0. 1020

-3

square inch
o^

mg/8.

0. 1450
9/5

(then add 32)
parts per mi II ion ~ I .0

155

APPENDIX

GLOSSARY

abandoned channel — A channel that was once an active or high-water chan-
nel, but currently flows only during infrequent floods.

active channel — A channel that contains flowing water during the ice-free
season.

active floodplain — The portion of a floodplain that is flooded frequently;
it contains flowing channels, high-water channels, and adjacent bars,
usually containing little or no vegetation.

aesthetics — An enjoyable sensation or a pleasurable state of mind, which
has been instigated by the stimulus of an outside object, or it may
be viewed as including action which will achieve the state of mind de-
sired. This concept has a basic psychological element of individual
learned response and a basic social element of conditioned social atti-
tudes. Also, there can be ecological conditioning experience because
the physical environment also affects the learning process of attitudes.

algae — Primitive plants, one or many-celled, usually aquatic and capable
of elaborating the foodstuffs by photosynthesis.

aliquot — A portion of a gravel removal area that is worked independently,
often sequentially, from the other portions of the area.

alluvial river — A river which has formed its channel by the process of

aggradation, and the sediment by which it carries (except for the wash
load) is similar to that in the bed.

arctic — The north polar region bounded on the south by the boreal forest.

157

armor layer — A layer of sediment that is coarse relative to ttie material
underlying it and is erosion resistant to frequently occurring floods;
it may form naturally by the erosion of finer sediment, leaving coarser
sediment in place or it may be placed by man to prevent erosion.

aufeis — An ice feature that is formed by water overflowing onto a surface.

such as river ice or gravel deposits, and freezing, with subsequent
layers formed by water overflowing onto the ice surface itself and
f reez i ng.

backwater analysis — A hydraulic analysis, the purpose of which is to

compute the water surface profile in a reach of channel with varying
bed slope or cross-sectional shape, or both.

bank — A comparatively steep side of a channel or floodplain formed by an
erosional process; its top is often vegetated.

bank-full discharge — Discharge corresponding to the stage at which the
overflow plain begins to be flooded.

bar — An alluvial deposit or bank of sand, gravel, or other material, at
the mouth of a stream or at any point in the stream flow.

beaded stream — A small stream containing a series of deep pools intercon-
nected by very small channels, located in areas underlain by permafrost.

bed — The bottom of a watercourse.

bed load — Sand, silt, gravel or soil and rock detritus carried by a stream
on, or immediately above its bed.

bed load material — That part of the sediment load of a stream which is

composed of particle sizes found in appreciable quantities in the shift-
ing portions of the stream bed.

158

bed, movable — A stream bed made up of materials readily transportable by
the stream flow.

bed, stream — The bottom of a stream below the low summer flow.

braided river — A river containing two or more interconnecting channels

separated by unvegetated gravel bars, sparsely vegetated islands, and,
occasionally, heavily vegetated islands. Its floodplain is typically
wide and sparsely vegetated, and contains numerous high-water channels.
The lateral stability of these systems is quite low within the boun-
daries of the active floodplain.

carrying capacity, biological — The maximum average number of a given organ-
ism that can be maintained indefinitely, by the habitat, under a given
regime (in this case, flow).

carrying capacity, discharge — The maximum rate of flow that a channel is
capable of passing.

channel — A natural or artificial waterway of perceptible extent which

periodically or continuously contains moving water. It has a definite
bed and banks which serve to confine the water.

configuration — The pattern of a river channel (s) as it would appear by
looking vertically down at the water.

contour — A line of equal elevation above a specified datum.

cover, bank — Areas associated with or adjacent to a stream or river that
provide resting shelter and protection from predators - e.g., undercut
banks, overhanging vegetation, accumulated debris, and others.

cover, fish — A more specific type of instream cover, e.g., pools,
boulders, water depths, surface turbulence, and others.

159

cover, instream — Areas of shelter in a stream channel that provide aquatic
organisms protection from predators or a place in which to rest, or
both, and conserve energy due to a reduction in the force of the cur-
rent .

cross section area — The area of a stream, channel, or waterway opening,
usually taken perpendicular to the stream center line.

current — The flowing of water, or other fluid. That portion of a stream

of water which is moving with a velocity much greater than the average
or in which the progress of the water is principally concentrated (not
to be confused with a unit of measure, see velocity).

datum — Any numerical or geometrical quantity or set of such quantities

which may serve as a reference or base for other quantities. An agreed
standard point or plane of stated elevation, noted by permanent bench
marks on some solid immovable structure, from which elevations are meas-
ured, or to which they are referred.

dewater — The draining or removal of water from an enclosure or channel.

discharge — The rate of flow, or volume of water flowing in a given stream
at a given place and within a given period of time, expressed as cu
ft per sec.

drainage area — The entire area drained by a river or system of connecting
streams such that all stream flow originating in the area is discharged
through a single outlet.

dredge — Any method of removing gravel from active channels.

drift, invertebrate — The aquatic or terrestrial invertebrates which have
been released from (behavioral drift), or have been swept from (catas-
trophic drift) the substrate, or have fallen into the stream and move
or float with the current.

160

duration curve — A curve which expresses the relation of all the units of
some item such as head and flow, arranged in order of magnitude along
the ordinate, and time, frequently expressed in percentage, along the
abscissa; a graphical representation of the number of times given
quantities are equaled or exceeded during a certain period of record.

erosion, stream bed — The scouring of material from the water channel and
the cutting of the banks by running water. The cutting of the banks
is also known as stream bank erosion.

fines — The finer grained particles of a mass of soil, sand, or gravel. The
material, in hydraulic sluicing, that settles last to the bottom of
a mass of water.

flood — Any flow which exceeds the bank-full capacity of a stream or chan-
nel and flows out on the floodplain; greater than bank-full discharge.

floodplain — The relatively level land composed of primarily unconsolidated
river deposits that is located adjacent to a river and is subject to
flooding; it contains an active floodplain and sometimes contains an
inactive floodplain or terrace(s), or both.

flood probability — The probability of a flood of a given size being

equaled or exceeded in a given period; a probability of I percent would
be a 100-year flood, a probability of 10 percent would be a 10-year
f lood.

flow — The movement of a stream of water or other mobile substances, or
both, from place to place; discharge; total quantity carried by a
stream.

flow, base — That portion of the stream discharge which is derived from

natural storage - i.e., groundwater outflow and the draining of large
lakes and swamps or other sources outside the net rainfall which
creates the surface runoff; discharge sustained in a stream channel,

161

not a result of direct runoff and without the effects of regulation,
diversion, or other works of man. Also called sustaining flow.

flow, laminar — That type of flow in a stream of water in which each par-
ticle moves in a direction parallel to every other particle.

flow, low — The lowest discharge recorded over a specified period of time.

flow, low summer — The lowest flow during <: typical open-water season.

flow, uniform — A flow in which the velocities are the same in both magni-
tude and direction from point to point. Uniform flow is possible only
in a channel of constant cross section.

flow, varied — Flow occurring in streams having a variable cross section
or slope. When the discharge is constant, the velocity changes with
each change of cross section and slope.

fork length — The length of a fish measured from the tip of the nose to the
fork i n the tail.

freeze front — A surface that may be stationary, which has a temperature
of 0 C and is warmer on one side of the surface and colder on the
other .

frequency curve — A curve of the frequency of occurrence of specific
events. The event that occurs most frequently is termed the mode.

gage — A device for indicating or registering magnitude or position in spe-
cific units, e.g., the elevation of a water surface or the velocity
of flowing water. A staff graduated to indicate the elevation of a
water surface.

geomorphology — The study of the form and <levelopment of landscape fea-
tures.

162

habitat — Ttie place where a population of animals lives and its sur-
roundings, both living and nonliving; includes the provision of life
requirements such as food and shelter.

high-water channel — A channel that is dry most of the ice-free season,
but contains flowing water during floods.

hydraulics — The science dealing with the mechanical properties of fluids
and their application to engineering; river hydraulics deals with
mechanics of the conveyance of water in a natural watercourse.

hydraulic depth — The average depth of water in a stream channel. It is
equal to the cross-sectional area divided by the surface width.

hydraulic geometry — Those measures of channel configuration, including
depth, width, velocity, discharge, slope, and others.

hydraulic radius — The cross-sectional area of a stream of water divided

by the length of that part of its periphery in contact with its contain-
ing channel; the ratio of area to wetted perimeter.

hydrograph — A graph showing, for a given point on a stream, the discharge,
stage, velocity, or another property of water with respect to time.

hydrology — The study of the origin, distribution, and properties of water
on or near the surface of the earth.

ice-rich material — Permafrost material with a high water content in the

form of ice, often taking the shape of a vertical wedge or a horizontal
I ens.

impervious — A term applied to a material through which water cannot pass
or through which water passes with great difficulty.

163

inactive floodplain — The portion of a floodplain that is flooded infre-
quently; it may contain high-water and abandoned channels and is
usually lightly to heavily vegetated.

island — A heavily vegetated sediment deposit located between two channels.

large river — A river with a drainage area greater than 1,000 km and a

mean annual flow channel top width greater than 100 m.

lateral bar — An unvegetated or lightly vegetated sediment deposit located
adjacent to a channel that is not associated with a meander.

Manning's equation — In current usage, an empirical formula for the calcula-
tion of discharge in a channel. The formula is usually written

- 1.49 ^ 2/5 ^1/2 .

0 = R S A.

^ n

mean flow — The average discharge at a given stream location computed for

the period of record by dividing the total volume of flow by the number
of days, months, or years in the specified period.

mean water velocity — The average velocity of water in a stream channel,
which is equal to the discharge in cubic feet per second divided by
the cross-sectional area in square feet. For a specific point location,
it is the velocity measured at 0.6 of the depth of the average of the
velocities as measured at 0.2 and 0.8 of the depth.

meander wave length — The average downvalley distance of two meanders.

meandering river — A river winding back and forth within the floodplain.
The meandering channel shifts downvalley by a regular pattern of ero-
sion and deposition. Few islands are found in this type of river and
gravel deosits typically are found on the point bars at the insides of
meanders.

164

medium river — A river with a drainage area greater than 100 km but less

2
than 1,000 km and a mean annual flow channel top width greater than

15 m but less than 100 m.

microhabitat — Localized and more specialized areas within a community or

habitat type, utilized by organisms for specific purposes or events, or
both. Expresses the more specific and functional aspects of habitat and
cover that allows the effective use of larger areas (aquatic and ter-
restrial) in maximizing the productive capacity of the habitat, (See
cover types, habitat).

mid-channel bar — An unvegetated or lightly vegetated sediment deposit lo-
cated between two channels.

parameter — A variable in a mathematical function which, for each of its
particular values, defines other variables in the function.

permafrost — Perennially frozen ground,

pit excavation — A method of removing gravel, frequently from below over-
burden, in a manner that results in a permanently flooded area. Gravels
are usually extracted using draglines or backhoes,

point bar — An unvegetated sediment deposit located adjacent to the inside
edge of a channel in a meander bend.

pool — A body of water or portion of a stream that is deep and quiet rela-
tive to the main current,

pool, plunge — A pool, basin, or hole scoured out by falling water at the
base of a water fal I ,

profile — In open channel hydraulics, it is the water or bed surface ele-
vation graphed aganist channel distance.

165

reach — A comparatively short length of a stream, channel, or shore.

regional analysis — A hydrologic analysis, i he purpose of which is to esti-
mate hydrologic parameters of a river by use of measured values of the
same parameters at other rivers within a selected region.

riffle — A shallow rapids in an open stream, where the water surface is
broken into waves by obstructions wholly or partly submerged.

riparian — Pertaining to anything connected with or adjacent to the banks
of a stream or other body of water.

riparian vegetation — Vegetation bordering floodplains and occurring within
f loodp I a i ns.

riprap - Large sediments or angular rock used as an artificial armor layer.

river regime — A state of equilibrium attained by a river in response to
the average water and sediment loads it receives.

run — A stretch of relatively deep fast flowing water, with the surface
essentially nont urbu I ent .

scour — The removal of sediments by running water, usually associated with
removal from the channel bed or f loodp lain surface.

scrape - A method of removing floodplain gravels from surface deposits using
tractors or scrapers.

sediment discharge — The volumetric rate of sediment transfer past a spe-
cific river cross section.

sinuous river — Sinuous channels are similar to meandering channels with
a less pronounced winding pattern. The channel may contain smaller

166

point bars and have less tendency for downvalley shifting. The channels
are more stable with respect to lateral shifting.

sinuousity — A measure of the amount of winding of a river within its flood-
plain; expressed as a ratio of the river channel length to the corres-
ponding valley length.

slope — The inclination or gradient from the horizontal of a line or sur-
face. The degree of inclination is usually expressed as a ratio, such
as 1:25, indicating one unit rise in 25 units of horizontal distance,

small river - A river with a drainage area less than 100 km and a mean

annual flow channel top width of less than 15 m.

split river — A river having numerous islands dividing the flow into two
channels. The islands and banks are usually heavily vegetated and
stable. The channels tend to be narrower and deeper and the floodplain
narrower than for a braided system.

stage — The elevation of a water surface above or below an established
datum or reference.

standing crop — The abundance or total weight of organisms existing in an
area at a given time.

straight river — The thalweg of a straight river typically winds back and
forth within the channel. Gravel bars form opposite where the thalweg
approaches the side of the channel. These gravel bars may not be ex-
posed during low flow. Banks of straight systems typically are stable
and floodplains are usually narrow. These river systems are considered
to be an unusual configuration in transition to some other configura-
tion,

subarctic — The boreal forest region.

167

suspended load — The portion of stream load moving in suspension and made

up of particles having such density of grain size as to permit movement
far above and for a long distance out of contact with the stream bed.
The particles are held in suspension by the upward components of turbu-
lent currents or by colloidal suspension,

talik — A zone of unfrozen material within an area of permafrost.

terrace — An abandoned floodplain formed as a result of stream degradation
and that is expected to be inundated only by infrequent flood events.

thalweg — The line following the lowest part of a valley, whether under
water or not; also usually the line following the deepest part or
middle of the bed or channel of a river or stream.

thermokarst — Landforms that appear as depressions in the ground surface
or cavities beneath the ground surface which result from the thaw of
ice-rich permafrost material.

top width — The width of the effective area of flow across a stream chan-
nel .

velocity — The time rate of motion; the distance traveled divided by the
time required to travel that distance.

wash load — In a stream system, the relatively fine material in near-perman-
ent suspension, which is transported entirely through the system,
without deposition. That part of the sediment load of a stream which is
composed of particle sizes smaller than those found in appreciable
quantities in the shifting portions of the stream bed.

water quality — A term used to describe the chemical, physical, and biolog-
ical characteristics of water in reference to its suitability for a
part i cu I ar use.

168

wetted perimeter — The length of the wetted contact between the stream of
flowing water and its containing channel, measured in a plane at right
angles to the direction of flow.

wildlife — All living things that are neither human nor domesticated; most
often restricted to wildlife species other than fish and invertebrates.

169

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Blank template to be used with matrix tables (see page 51)

50272-101

REPORT DOCUMENTATION
PAGE

1. REPORT NO.

FWS/OBS-80/09

3. Recipient's Accession No.

4. Title and Subtitle

GRAVEL REMOVAL STUDIES IN ARCTIC AND SUBARCTIC FLOODPLAINS
IN ALASKA - GUIDELINES MANUAL

5. Report Date

June 1980, Pub. date

*• N/A

7. Author(s)

WOODWARD-CLYDE CONSULTANTS

8. Performing Organization Rept. No.

9. Performing Organization Name and Address

Woodward-Clyde Consultants

4791 Business Park Blvd., Suite #1

Anchorage, Alaska 99503

10. Project/Task/Work Unit No.

11. Confract(C) or Grant(G) No.

(G)

12. Sponsoring Organization Name and Address

U. S. Fish and Wildlife Service
1011 East Tudor Road
Anchorage, Alaska 99503

13, Type of Report A Period Covered

Final Report
1975 - 1980

14.

15. Supplementary Notes

This report is part of Interagency Energy - Environment Research and Development Program
of the Office of Research and Development, U.S. Environmental Protection Agency

16. Abstract (Limit: 200 words)

A 5-year investigation of the effects of floodplain gravel mining on the physical
and biological characteristics of river systems in arctic and subarctic Alaska
is described. Twenty-five sites were studied within four geographic regions. The
sites were selected such that within each of the regions the group of sites exhibited
a wide range of river and mining characteristics. The field data collection program
covered the major disciplines of hydrology/hydraulics, aquatic biology, water
quality, and terrestrial biology. In addition, geotechnical engineering, and aesthe-
tics site reviews were conducted. A wide range of magnitude and type of physical and
biological changes were observed in response to mining activity. Little change was
observed at some sites, whereas other sites exhibited changes in channel morphology,
hydraulics, sedimentation, ice regime, aquatic habitat, water quality, benthic
macroinvertebrates, fish utilization, vegetation, soil characteristics, and bird and
mammal usage.

Two major products of the project are a Technical Report which synthesizes and
evaluates the data collected at the sites, and a Guidelines Manual that aids the
user in developing plans and operating material sites to minimize environmental
effects.

17. Document Analysis a. Descriptors

Gravel Removal, Alaska, Arctic, Subarctic, Floodplains, Streams, Scraping, Pit
Excavation, Environmental Impacts, Hydrology-Hydraulics, Aquatic Biology, Terrestrial
Ecology, Water Quality, Aesthetics, Geotechnical Engineering, Site Selection, Site
Design.

b. Identifiers/Open-Ended Terms

c. COSATI Field/Group

IS. Availability Statement

19. Security Class (This Report)

Unclassi f ied

21. No. of Pages
165

Re lease un 1 imi ted

^- ern=£i%i'if /y^cr'""

22. Price

(See ANSI-Z39.18)

See Instructions on Reverse

OPTIONAL FORM 272 (4-77)
(Formerly NTlS-35)
Department of Commerce

^ -(iVS GOVERNMENT PRINTING OFFICE: 1980 699-278

W HO I

DOCUMENT

COLLECTION

REGIONAL OFFICE BIOLOGICAL SERVICES TEAMS

Region 1

Team Leader

U.S. Fish and Wildlife Service

Lloyd 500 Building, Suite 1692

500 N.E. Multnomah Street

Portland, Oregon 97232

FTS: 429-6154

COMM: (503)231-6154

Region 2

Team Leader

U.S. Fish and Wildlife Service

P.O. Box 1306

Albuquerque, New Mexico 87103

FTS: 474-2971

COMM: (505) 766-1914

Region 4

Team Leader

U.S. Fish and Wildlife Service

17 Executive Park Drive, N.W.

P.O. Box 95067

Atlanta, Georgia 30347

FTS: 257-4457

COMM: (404) 881-4457

Region 5

Team Leader

U.S. Fish and Wildlife Service

One Gateway Center

Suite 700

Newton Corner, Massachusetts 021 58

FTS: 829-9217

COMM: (617) 965-5100, ExL 217

Region 3

Team Leader

U.S. Fish and Wildlife Service

Federal Building, Fort Snelling

Twin Cities, Minnesota 551 11

FTS: 725-3593

COMM: (612) 725-3510

Region 6

Team Leader

U.S. Fish and Wildlife Service

P.O. Box 25486

Denver Federal Center

Denver, Colorado 80225

FTS: 234-5586

COMM: (303) 234-5586

Alaska Area Office
Team Leader

U.S. Fish and Wildlife Service
1011 E.Tudor Road
Anchorage, Alaska 99503
FTS: 399-01 50 ask for
COMM: (907) 276-3800

^
^

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