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Technical Report CHL-97-29

October 1997

US Army Corps

of Engineers
Waterways Experiment
Station

Needs Assessment for Water-Level Gauging
Along the Texas Coast for the U.S. Army
Engineer District, Galveston

by Nicholas C. Kraus, WES

Carroll I. Thurlow, Daniel J. Heilman, Anne-Lise Lindquist,
Mark W. Earle, Texas A&M University-Corpus Christi

Approved For Public Release; Distribution Is Unlimited

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Prepared for U.S. Army Engineer District, Galveston

The contents of this report are not to be used for advertising,
publication, or promotional purposes. Citation of trade names
does not constitute an official endorsement or approval of the use
of such commercial products.

The findings of this report are not to be construed as an

official Department of the Army position, unless so desig-
nated by other authorized documents.

rane ON RECYCLED PAPER

Technical Report CHL-97-29
October 1997

Needs Assessment for Water-Level Gauging
Along the Texas Coast for the U.S. Army
Engineer District, Galveston

by Nicholas C. Kraus
U.S. Army Corps of Engineers
Waterways Experiment Station

3909 Halls Ferry Road
Vicksburg, MS 39180-6199

Carroll |. Thurlow, Daniel J. Heilman, Anne-Lise Lindquist, Mark W. Earle

Conrad Blucher Institute for Surveying and Science
Texas A&M University-Corpus Christi

6300 Ocean Drive

Corpus Christi, TX 78412-5599

Final report
Approved for public release; distribution is unlimited

MBL/WHO!I

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O 0301 O034b24 3

Prepared for U.S. Army Engineer District, Galveston
Jadwin Building, P.O. Box 1229
Galveston, TX 77553-1229

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US Army Corps

of Engineers
Waterways Experiment
Station

FOR INFORMATION CONTACT:

PUBLIC AFFAIRS OFFICE

U.S. ARMY ENGINEER

WATERWAYS EXPERIMENT STATION
3909 HALLS FERRY ROAD
VICKSBURG, MISSISSIPPI 39180-6199
PHONE: (601) 634-2502

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Waterways Experiment Station Cataloging-in-Publication Data

Needs assessment for water-level gauging along the Texas coast for the U.S. Army Engineer
District, Galveston / by Nicholas C. Kraus ... [et al.] ; prepared for U.S. Army Engineer
District, Galveston.

68 p. : ill. ; 28 cm. — (Technical report ; CHL-97-29)

Includes bibliographic references.

1. Water levels — Texas. 2. Navigation — Texas. 3. Stream measurements — Texas.
|. Kraus, Nicholas C. II. United States. Army. Corps of Engineers. Galveston District.

lll. U.S. Army Engineer Waterways Experiment Station. IV. Coastal and Hydraulics

Laboratory (U.S. Army Engineer Waterways Experiment Station) V. Monitoring Completed

Navigation Projects Program (U.S.) VI. Series: Technical report (U.S. Army Engineer

Waterways Experiment Station) ; CHL-97-29.

TA7 W34 no.CHL-97-29

Contents

FAC Cerrar rere eee ae rent aE A Rees Re EN INES ee Vill
Conversion Factors, Non-SI to SI Units of Measurement....................::000 xi
NST TrOCUCTON ~.-225c. Meee eee eee See, Santi mentees Same. PS SOU, Se, 1
Backsround: tor theyNeedsyASsessmentracenceeese nee eee eee 1
Cost-Sharing Partners and the Needs Assessment...............::cssseceeseeeeeerens 6
OBECE VES errs cane eee reece sce teee cc eh Pre cenaen aime cRotretee scott dv acentte Aitenceauees 7
Scope Of thigiReporty ses. ae ee eee weiner fe Boi eens 8
2-Water Level Definition, Measurement, and Properties. .................:.::0000 9
HIStOriGall Seem Oy) kei eee hake sas sac Less ca eoan ko Loss ccucah eer wo MONE ORIN 9
Wiatermleevel and eliidale) atunnis reser soe enener ce tanne et aneint anne unas enen Ean ae 10
Basic concepts of tides and tide measurement .................:ccssceseeeseeeees 11
ideveauserancitide:Stattomeceesessece eee ees ee ec eee ie:
TUR GS AULA Git ech Rope Se APB SL Pesees BEL EL REPRE BOREL ASAE RSS ROMS COEE 13
CharacteromthemiuderAlongsthe Miexas| Coaster eee 13
3-Present Water-Level Measurement Networks Along the
MEX ASIC OAS bese Soe sass sree Nae ee ee cee ae se eae? otto epee etn ce ae 22
COON GC apaorlity ese ee cs reece e ce rer ie ee ee ee a act nee ere em 22
Present Galveston District Field Practice and Identified Needs.............. 22
Locations of Galveston District Tide Staffs.................c::ccccessccesscesseeeseees 26
NMIPMFandiNGNVP Ditterencem cers coe cee ec seen ene eee ane 2
A-ComimunicatonsAltemativesie see tones ee eee ees 28
Real — Thies REPOS pete cette note ccs eete nee ccs ee reeees ee er enaee ee E 28
Recommendationsjand COstSre ee ere eee ee eee 29
@entralizediE CSy Sterne csr sche seers se ee eee ean eM ON net 30
ACCESS tovArchived Datars senor col 2 aveiiesrcets recent ceased ce 31

5-Consideration of an Expanded Network..............::sscssscessseeceeeeeteeteesneenee 34

IPTESEME S CAG IOs NEL WO Kernen seeee ene tence tc... cs: aces cunetoneeeteamemeeenneesn caus: 34
IBxam ple OM Need iol GaWOespammserareseeen- cc. <sscccccsnessnnencateneerenenenenenes 42
JIG o) Wiel aYeoVeFat! OLE STENT OV NS) onccencenscecnoncascococa eco dE SEBONEoHOE dodboncaobodcoconopzomccaqosd 43
6-Conclusions and Recommendations ...............:ceccessseeseeeseseseeenseeseeesseenes 45
Federal and State Cooperation (Backbone Network) .............:2:::cesee 45
Real=ime Voice Reportin eee csetecce sone ee oe ene dence scores ecoesse ns Sameer 46
raining of Galveston!District Persomneliser.:crrece-see--cee---oeccesoces-neseeeeee 47
Project Wow Waters aturnsiess serene srss nee escte scons aadoics sccoencee cere eee 47
Engineering Utility ofArchived Datacenters cess eee esos eee 48
Project-Specific|@perationaliGaucesmesseerce erence cee eee eee 49
Outside (Gulf-side) Gauges and Wave Measurement ..............:-e::eeeeeees 50
INVEStIGationiOf DGPS Mercere scree oro sence 5)!
REPEren COS i. icsccscecdscecs de oetae tees een esa eee RR En 2 aloe 54

Appendix A: Locations and Capabilities of TCOON Stations,

September 1996. si2cAeeetaeoee eees eee ces eee eee Al
Appendix B: Locations of Galveston District Tide Staffs,

September sl G9 Gis eee eo Pa cere lace aac ate eee Bl
SF 298

List of Figures

RigurenlemstudyasitesthemlexasicOaSteresesreetem eee eee nee 2
Figure 2. 1992 water level for Los Angeles, California ................000060 16
Figure 3. 1995 water level for Sandy Hook, New Jersey ...............:00008 17
Figure 4. 1993 water level for Fernandina, Florida................:.ccccscesseeeees 18
Figure 5. 1995 water level for Bob Hall Pier, Texas ............0..:.c::csceseeeee 19

Figure 6. 1994 water level for S. Padre Island Coast Guard Station........ 20
Figure 7. 1995 water level for Packery Channel, Texas.................00.0000-- 21
Figure 8. Tide staff mounted on survey table at Channel to Victoria.......24

Figure 9. Freeport Entrance Channel at the U.S. Coast Guard Station,

SUDISIGE se. 5. dec teecereedrre eccrine sano Seeteemes eee ee care 24
Figure 10.Staff being replaced at Fulton Harbor public boat ramp,

ATATISASHES AV sere eee static eg SoA Seo eee INS oa ck LO clon eet eR D5
Figure 11. TCOON quality control station list .........0..cccccccsssessseseesceeeeeeee 3
Figure 12. TCOON quality control station 001: Naval Air Station........... 33
Figure 13.Chart A (includes NOAA charts 11342 and 11343) ........0.0..... 37
Figure 14.Chart B (includes NOAA chart 11332) .0...0..ccccceeesseeseeeeeeeeeees 37
Figure 15.Chart C (includes NOAA charts 11326 and 11329).................. 38
Figure 16.Chart D (includes NOAA chart 11323)........cccccccsssssssseseseseseeees 38
Figure 17.Chart E (includes NOAA charts 11321 and 11322).........0........ 39

Figure 18.Chart F (includes NOAA charts 11316,11317, and 11319)......39

vi

Figure 19.Chart G (includes NOAA charts 11313 and 11315)................. 40

Figure 20.Chart H (includes NOAA charts 11307 and 11308)................. 40
Figure 21.Chart I (includes NOAA chart 11304) .0......ee cc eessceseeeeeeneeeneee 41
Figure 22. Chart J (includes NOAA charts 11301 and 11303.........00000... 4]

Figure 23.Plot of simultaneous water-level records at three neighboring
nontidalistationstalongthelGIW NW pees cere eee 43

List of Tables

Table 1. Elevation Difference Between mlt and NGVD 29 ..................... 27
Table 2. Features of Selected Voice-Reporting Systems.................:c0000 28
Table 3. Estimated Cost of Stand-Alone (per gauge) Voice-Reporting
DSSS Sy li a ie eh NR a hn co rt eT 30
Table 4. Gauges with Speech Capability, December 1996....................... 31

Table 5. Summary of Water-Level Stations on the Texas Coast and
Inland! Coastal Waters xc3ccccc.ce~cetaeseree ston. enter cat Sees 35

Table 6. Recommended Long-Term Water-Level Stations (Backbone
Network) and Required Short-Term Stations to Fill in Gaps

LOT SUPPOLLO MUSA CE) Operation ses-se een est neem Sy)
Table Al. TCOON and NOS Water-Level Stations............0....cccccesees0ee A2
Table B1. Locations of USACE — Galveston District Tide Staffs .......... B2

Vil

Viil

Preface

The needs assessment for water-level measurement and associated
information described in this report was conducted for the U.S. Army
Engineer District, Galveston (CESWG). Work was performed under
Modification/Amendment No. P00003 of Contract No. DACW64-95-C-
0018 with the Conrad Blucher Institute (CBI) for Surveying and Science,
Texas A&M University-Corpus Christi, in support of the Texas Coastal
Ocean Observation Network (TCOON). Notice of authorization to
proceed with work under the amendment was received on 29 April 1996.
An interim draft of this report was provided to CESWG on 30 September
1996.

The assessment was performed by Dr. Nicholas C. Kraus, formerly
Director of the Division of Coastal and Estuarine Processes, CBI, and
presently Research Scientist, Coastal and Hydraulics Laboratory, CHL),
U.S. Army Engineer Waterways Experiment Station (WES); Mr. Carroll I.
Thurlow, consultant to TCOON and formerly Chief of the Tides and
Water-Level Program for the National Ocean Service (NOS), National
Oceanic and Atmospheric Administration; and former CBI staff members;
Mr. Daniel J. Heilman and Ms. Anne-Lise Lindquist, Research Scientists,
and Mr. Mark W. Earle, Communications Specialist. Technical points of
contact at CESWG were Mr. John Rozsypol, Ms. June Keller, Mr. Ron
Meyers, and Mr. Tom Hunt. The field reconnaissance benefited from the
assistance of numerous staff members of Area Offices and Field Offices of
the Galveston District: Mr. Randy Batiste, Port Arthur Field Office;

Mr. Isidro Garcia, Brownsville Field Office; Mr. Ramon Sierra, Southern
Area Office, Corpus Christi; Mr. David Torrez, Bay City Field Office; and
Mr. Rick Tryals, Northern Area Office, Galveston. General assistance to
the study was also provided by Galveston District staff members from the

Southern Area Office, Corpus Christi: Mr. Carl Anderson, Area Engineer;
Mr. Domingo Galindo, Project Engineer; and Mr. Elijio Garza, Civil
Engineer.

This study received assistance from TCOON staff at CBI, in particular,
by former TCOON Project Manager Mr. T. Zachariah Jeffries. The
cooperation of NOS staff in providing water-level data is appreciated.

At the time of publication of this report, Dr. James R. Houston served
as Director of the CHL; Assistant Directors were Messrs. Richard A.
Sager and Charles C. Calhoun, Jr. Director of WES was Dr. Robert W.
Whalin. Commander was COL Robin R. Cababa, EN.

The contents of this report are not to be used for advertising, publication,
or promotional purposes. Citation of trade names does not constitute an
official endorsement or approval of the use of such commercial products.

Conversion Factors, Non-Sl to
SI Units of Measurement

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

Co) To Obtain
[cubicyards 0.7645549 cubic meters |
fest oaa0a meer

| miles (U.S. nautical) 1.852 kilometers

miles (U.S. statute) 1.609347 kilometers

1 Introduction

This report contains a reconnaissance assessment of needs for water-
level information by the U.S. Army Engineer District, Galveston
(CESWG). The CESWG conducts navigation channel maintenance and
operations along the Texas coast from the Sabine River on the north to the
Brownsville Ship Channel on the south (Figure 1). The Texas coast is
approximately 350 miles' long and contains more than 1,000 miles of
deep- and shallow-draft navigation channels running through bays,
estuaries, lagoons, and rivers, as well as eight maintained channels running
to the Gulf of Mexico through inlets. The CESWG has identified a
general need to have both real-time and recorded data on water level for
conducting its navigation channel maintenance and operation, coastal
engineering, and environmental regulatory functions in an economical and
accurate way. This report identifies general and some specific needs for
water-level information, and it gives a recommendation for obtaining such
information.

Background for the Needs Assessment

The CESWG maintains and operates Federally authorized channels
and waterways along the coast of Texas, which include ship channels and
the Gulf Intracoastal Waterway (GIWW). In support of its navigation
mission, CES WG dredges more than 40 million cu yd of sediment
annually. Both Government surveyors and the CESWG’s dredging and
other contractors perform hydrographic surveys in support of these
dredging operations. Such activities associated with navigation channel

A table of factors for converting non-SI units of measurement to SI units is presented on page x.

Chapter 1 Introduction

lexas

Victoria

East Matagorda Bay
Matagorda Bay

San Antonio Bay

Copano Bay
Aransas Bay

Corpus Christi
Bay s

Upper Laguna GULF OF MEXICO

Madre

Brownsvillé South Padre Island

Mexico

Figure 1. Study site, the Texas coast

maintenance and operation require knowledge of water level prior to,
during, and after dredging. The CESWG also conducts coastal
engineering works and environmental regulatory functions that involve
water-level data. In conducting these activities, information in real time
(during the activity) is often needed, whereas in some situations
convenient access to recently recorded measurements is sufficient.

Chapter 1 Introduction

In a more general context, the National Ocean Service (NOS) of the
National Oceanic and Atmospheric Administration (NOAA), U.S.
Department of Commerce and U.S. Army Corps of Engineer (USACE)
Districts nationwide are converting to mean lower low water (mllw) as the
chart datum for navigational tidal waters of the United States. The NOS is
revising charts for the east and Gulf coasts with mllw as chart datum, a
several-year process. Tidal datums such as mllw are calculated and
published by NOS, and, by mandate of the Congress of the United States,
the USACE must reference this NOS chart datum. The Districts are
following guidance issued by Headquarters, USACE, in Engineer
Technical Letter (ETL) 1110-2-349 (USACE 1993). Also, by
ETL 1110-1-152 (USACE 1994), Districts are required to implement the
North American Vertical Datum of 1988 (NAVD 88) as a replacement for
the National Geodetic Vertical Datum of 1929 (NGVD 29).

The NGVD 29, a standard geodetic reference for elevations, is
sometimes confused with or referred to synonymously as mean sea level
(msl). The datum msl is defined by NOS as the average of the hourly
values of water-level readings of a specific 19-year tidal epoch called the
National Tidal Datum Epoch (NTDE), presently 1960 to 1978. However,
because there are many variables controlling water level, and because a
geodetic datum represents a best-fit surface over a broad area and not toa
specific area, NGVD 29 is not, in general, equal to msl. The geodetic
datum can deviate from msl by 1 ft or more, depending on location. Thus,
NGVD 29 and NAVD 88 are not equal to msl, do not bear a consistent
relation to msl along a coast, and are fixed, whereas the elevation of msl
typically changes slowly with time.

For several decades, CES WG has recognized that standard low-water
datums such as mean low water (mlw) and mllw that are defined in terms
of the daily phase of the tide as computed by NOS are not adequate as a
navigation datum within the waterways along the Texas coast. This
recognition owes to four observations:

a. In the shallow inland coastal waters of Texas, the astronomical
tidal signal is very weak, and the seasonal change in water
elevation within waterways typically exceeds the range in daily
tidal elevation for long periods of time (as long as months).

Chapter 1 Introduction

b. Persistent strong winds that blow daily or move through an area as
a weather front have a much greater influence on the change in the
water level on the shallow inland coastal waters of Texas,
producing either water setup or setdown, depending on location in

a water body.

c. Storm surges and water-level changes accompanying differences in
air pressure can greatly change water level in shallow basins.

d. Occasional strong river discharges, such as from the Brazos and
Colorado Rivers, will temporarily alter the water level more than
the astronomic forces.

All four of these phenomena are not directly related to the
astronomical or deterministic tide and tidal datums as presently defined by
NOS.

In addition, recent densification of tide stations on the Texas coast and
inspection of the resultant data have shown that, for much of the GIWW
and associated channels distant from inlets, an mllw tidal datum cannot be
computed following NOS standards and procedures. The mllw datum is
obscure because the meteorologically induced water motions that mask the
daily range of astronomic highs and lows is too small. An NOS technical
report (Gill, Hubbard, and Dingle 1995) documents the nontidal character
of portions of the Laguna Madre. This finding applies to much of the
GIWW and associated coastal inland channels. A navigation datum must
be developed for such areas as well. The establishment of a fixed low-
water datum, such as is used in the Great Lakes and on the Mississippi
River for navigational purposes, is the practical solution. Such a datum
should be low enough that the water level will seldom, if ever, fall below
it. This datum can be readily implemented by specifying the proper design
channel depth in terms of the NOS chart datum for the project water body.

In light of such observations, in the 1950s the CES WG established a
navigation datum which it called “mean low tide” (mlt) and defined it in
terms of a fixed vertical reference, namely, NGVD 29. For example, in
the Corpus Christi Bay area, mlt is 1 ft below NGVD. Accuracy
achievable with modern instrumentation for measuring water level, as well
as the requirement of reference to chart datum, bring the need to relate mlt

Chapter 1 Introduction

to mllw and, preferably, to an as-yet-to-be defined navigation low-water
datum for portions of the inland coastal waters of Texas. A rational
navigation datum for the Texas coast must be developed and implemented
that accounts for the extended periods of time during which water level
along the Texas coast lies significantly below mllw.

According to Engineer Manual (EM) 1110-2-1003 (USACE 1991),
page 7-1, “when elevations are referred to a tidal reference plane in coastal
waters of the United States, mean lower low water (mllw) shall be used as
the vertical datum.” The manual further states “In coastal areas, every
attempt should be made to assure that USACE datums are the same as, or
have a direct relationship to (underlining added by present authors), the
NOS chart datums. This is essential to ensure consistency for mariners
and others using Federal map and chart products.... In making a
determination as to the correct datum, Congressional intent (authorization
documents) should be considered.” The EM also states “If the tidal datum
that is used is different from mllw, a diagram should be included on the
drawings to indicate the relationship between the project datum
(underlining added by present authors) and mllw. The relationship to
NGVD 29 should also be shown.” Presumably, based on more recent
guidance in ETL 1110-1-152 (USACE 1994), the relationship to
NAVD 88 should now be shown.

It is clear that guidance provided by USACE technical documents
holds provision for definition of project navigation datums, where
warranted. If it is not feasible to determine mllw or if it is technically
unsound to employ mllw as a navigation datum, then USACE Districts
have the authority to develop an appropriate navigation datum. This
project datum must be related to mllw or NOS chart datum, if available,
for consistency between Federal agencies and in publishing Federal maps
and charts.

Since implementation of NGVD 29, the Texas coast has undergone
substantial geomorphic change under the influence of natural and human
forces that have altered both the relative location of the water level with
respect to land and the range of water-level variation. Along the Texas
coast, since the beginning of water-level gauging by NOS and its
predecessor organizations (Coast Survey, Coast and Geodetic Survey) in

Chapter 1 Introduction

the early1880s, sea level along the Texas and Louisiana coasts has been
rising, relative to the land, in great part due to subsidence (Swanson and
Thurlow 1973). The rate of relative sea-level rise varies along the Texas
coast, but has been measured to be on the order of several millimeters per
year (Swanson and Thurlow 1973; Lyles, Hickman, and Debaugh 1988),
depending upon location. Relative changes in land-water elevation will
directly alter water-level datums at the site of inland-water and coastal
operational activities of CES WG, and these changes must be tracked
through water-level gauging to fixed benchmarks on land. The National
Research Council (1987) has published a monograph discussing the
engineering implications of sea-level rise.

Determination of the relation of mlt or of another navigation datum to
extreme annual low water level, as well as to mllw as required, will enable
CESWG to assure the proper navigable depth, while satisfying Federal-
wide and USACE policy. The complex water-level variations present on
the Texas coast and along its inland coastal waters necessitate measure-
ment of local water level and collection of long-term time series of
measurements. Operational requirements in support of dredging activities
call for real-time reporting of the data in many situations.

Cost-Sharing Partners and the Needs Assessment

The State of Texas, through sponsorship by the Texas General Land
Office (TGLO) and the Texas Water Development Board (TWDB), has
deployed and operates a system of tide gauges called the Texas Coastal
Ocean Observation Network (TCOON) (Michaud, Thurlow, and Jeffress
1995). TCOON is maintained to national standards and procedures
established and promulgated by the NOS. TCOON complements eight
NOS gauges presently operating on the Texas coast. As of September
1996, the TCOON consisted of some 40 gauges, most of which were
located in inland coastal waters, with three gauges located offshore near
the fairway of the Galveston Ship Channel and sponsored by CESWG.
The main purpose of the TCOON has been to provide water-level
information to the TGLO for marine boundary determination (boundary
between state-owned land and private land) and to the TWDB for its
estuary and bay circulation and salinity studies.

Chapter 1 Introduction

The TGLO has proposed that the CESWG become a cost-sharing
partner of the TCOON, through which the needs of the District for water-
level information can be met. The cost-sharing partnership would support
the backbone of primary stations (long-term observations) and subordinate
stations (short-term observations — on the order of 3 months to 3 years)
upon which the programs of all agencies would depend. The partnership
must also consider specific gauges and special requirements identified by
CESWG as necessary to conduct its missions.

Water-level measurement needs of the CESWG in support of its
navigation channel maintenance, coastal engineering, and regulatory
functions will not always coincide with those of the state agencies of
Texas in their marine boundary definition and environmental modeling
activities. On the other hand, all potential users of water-level information
will require a certain backbone of primary gauges and infrastructure of
personnel and equipment to support their needs. It is appropriate and cost-
effective to share financial and technical responsibility for a combined
state and Federal measurement system for water level. As much as
possible, the water-level measurement system should address the widest
possible community needs while maintaining national standards.

Objectives

The overall objective of the present study was to define the
requirements or needs of CESWG for water-level and associated
information along the Texas coast. This report supersedes an interim
working report submitted to CESWG on 30 September 1996. Major
elements of this needs assessment are:

a. Locate and map existing CES WG tide staffs and document existing
differential leveling connections with NGVD 29 for providing
continuity with future water-level gauging.

b. Determine the general locations and numbers of water-level gauges
required to support CES WG operations.

c. Identify the types and forms of water-level information, such as
method of access during ongoing dredging activities and
subsequent archival and retrieval methods.

Chapter 1 Introduction

d. Conduct proof-of-concept pilot projects to deliver real-time data on
water level to CESWG offices.

e. Make recommendations on alternatives for establishing local
project navigation datums that may not be related to the phase of
the tide, related to mllw or appropriate chart datum, for CESWG

use.
f. Document results in a report.

The needs assessment encompassed numerous tasks, including:
coordination and information gathering with CESWG; inventory of
existing CESWG tide staffs; assessment of the need for gauges according
to present and possible future activities of the District, leading to develop-
ment of a preliminary design plan and evaluation of alternatives;
reconnaissance of existing and potential sites for water-level gauges;
development of recommendations for water-level measurement and
communications hardware; and general guidance on time and costs for
implementing the recommended plan.

Scope of this Report

Chapter 1 of this report contains the background and objectives of the
study. Water-level definitions and the character of the tide along the coast
of Texas are discussed in Chapter 2, which includes concepts and
nomenclature used throughout the report. Present water-level measure-
ments available along the coast of Texas are given in Chapter 3. Chapter 4
describes communications alternatives for supplying real-time, voice-
reported, and archived data to the CESWG. Chapter 5 describes the
preliminary design of a water-level network aimed to provide real-time
data to the District, as well as to give general access to the database.
Chapter 6 contains a summary with main conclusions and
recommendations. Appendices contain listings of detailed information
developed in this needs assessment.

Chapter 1 Introduction

2 Water Level Definition,
Measurement, and
Properties

This chapter introduces basic nomenclature related to tidal datums and
water-level measurement. Some typical characteristics of the water level
observed on the Texas coast are compared to those from tide records on
the Atlantic Ocean and Pacific Ocean coasts of the United States. The
material is intended to provide a background for further technical
discussion and to serve as motivation for establishing an appropriate
navigation datum for the inland coastal waterways of Texas.

Historical Setting

Tidal datums and their application have been an issue in the United
States since the founding of the nation. Both the need to establish a line of
delineation between the land and sea interface and the appropriate method
for determining the proper elevation were addressed early by the nation.

In 1807, the U.S. Congress assigned to the Coast and Geodetic Survey
the tasks of delineating the sea-land interface and displaying it on charts
(Shalowitz 1964). That agency, apparently having most experience on the
U.S. east coast (where the astronomical tide is very regular), concluded
that the most appropriate way of determining that interface or line would
be by measurements of the rise and fall of the tide. This procedure
entailed setting of a tide gauge, which was connected by differential
leveling to fixed points on the land that could be used by engineers to
survey the sea-land interface for charting. These procedures have

Chapter 2 Water Level Definition, Measurement, and Properties

10

essentially continued, with some modification, throughout the history of
the country. Eventually, a national network of permanently operating
water-level measurement stations was established to support the charting

activity.

Long-term tidal measurements from the U.S. Coast and Geodetic
Survey were the basis for establishing a boundary indicating ownership
between private upland and sovereign submerged lands (the landmark case
Borax Consolidated, Ltd. vs. Los Angeles, circa 1935; see Shalowitz
(1964)). The result of this decision by the U.S. Supreme Court was
carried over by the state courts to be the accepted method for dealing with
boundary issues. An 18.6-year water-level record, which corresponds to a
complete cycle of progression of the moon’s nodes along the ecliptic
(described by Meton in the fifth century before Christ), is believed to
account for all the astronomical variations in the ranges of the tide.

Also, it was believed for many years that the tides rose and fell
periodically and the application of a mean high water was appropriate for
all coastal waters. However, as more long-term tide stations have been
operated throughout the United States, we have found that the
astronomical gravitation is not always dominant. The tidal force is
frequently exceeded by meteorological forces, acting both over the long
term (seasons) and in the short term (hours and days through strong winds
and changes in air pressure accompanying passage of weather fronts).
Meteorological forcing can be particularly significant in shallow-water
bodies, such as along the Texas coast. Observations from the TCOON
have clearly shown that tidal datums established through traditional
procedures are not well-suited within the bays and estuaries along the
Texas coast for boundary, regulatory, or navigational purposes.

Water Level and Tidal Datums

This section reviews key concepts and notation relevant to the needs
assessment. Definitions of tidal datums and associated nomenclature and
concepts can by found in the NOS “Tide and Current Glossary” (Hicks
1989), ina USACE Special Report (Harris 1981), in the USACE Engineer
Manual entitled “Water Levels and Wave Heights for Coastal Engineering
Design” (USACE 1989), and in the EM entitled “Hydrographic

Chapter 2 Water Level Definition, Measurement, and Properties

Surveying” (USACE 1991). A concise but authoritative overview of tidal
datums and their various uses is given in Hicks (1985, 1986).

Basic concepts of tides and tide measurement

The tide is defined by NOS as the periodic rise and fall of the water
resulting from gravitational interactions between the sun, moon, and earth
(Hicks 1989). The term “tide” refers to the astronomically forced changes
in water level, which is deterministic or predictable. Astronomical or
daily tide should be distinguished from other contributions to changes in
water level, including meteorological forcing (seasonal changes in sea
level, changes caused by daily wind or to passage of weather fronts, etc.),
terrestrial inputs (rain runoff or river discharge), and atmospheric forcing
(change in air pressure). The distinguishing of periodicity produced by
astronomical forcing and by diurnal and:longer-term wind forcing, for
example, has not been well addressed in tidal datum definition. Similarly,
the distinguishing of variation in daily water (tidal) level and in annual
water elevation does not seem to have been well addressed in the United
States with regard to definition or determination of a navigation datum. In
the following, standard NOS definitions for selected tidal datums are given
for reference in this report.

Low water is the minimum height reached by a falling tide. Low
water occurs according to the periodic tidal forces and the acting
meteorological, hydrologic, and oceanographic conditions. For tidal
datum computation, the minimum height is not considered a low water
unless it contains a tidal low water (Hicks 1989).

Mean high water (mhw) and mean low water (mlw) are,
respectively, the averages of all the high-water heights and low-water
heights observed over the NTDE. For stations with time series shorter
than 19 years, simultaneous comparisons with a contro] station are made
to determine the equivalent datum of the NTDE. Also, strictly speaking,
to be counted as a high, each high water must be 0.10 ft or more above,
and must occur 2 hr or more later than the adjacent low waters.
Analogous considerations hold for definition of low waters.

The mean range of tide, denoted as “Mn” by NOS, is the difference in
height between mhw and mlw. Thus, Mn corresponds to a tidal range

Chapter 2 Water Level Definition, Measurement, and Properties

11

12

defined in terms of daily highs and lows and does not include such
changes as a seasonal variation in water elevation. Note that Mn is not a
tidal datum because it is not an elevation or level, but a range. Mean Tide
Level (mt!) or “half tide level” is a tidal datum and is the arithmetic mean
of mhw and mlw. The mtl may lie above or below msl by an amount
depending on the relative amplitudes of the diurnal (having a period of
approximately 1 lunar day) components of the tide.

Mean higher high water (mhhw) and mean lower low water (mllw)
are, respectively, the averages of the higher high water heights and lower
low water heights of each tidal day (or lunar day; 24.84 solar hr) observed
over the NTDE. For example, if there are two lows in a tidal day, the
lower of the two is used to compute mllw for that day. The mllw is
presently used by NOS as a nautical chart datum.

Tide gauge and tide station

A tide gauge, or water-level gauge in a more general sense, is an
instrument for measuring the rise and fall of the tide or water level.
Presently, acoustic gauges and pressure gauges are used as automated
water-level measurement systems because of their reliability and
capability to produce an electronic signal for convenient processing.

These measurement systems also require little power and are suited for
remote sites where the power unit must be self-contained. A tide staff is a
simple form of tide gauge and consists of a vertical graduated staff from
which the height of the water can be read visually.

A tide station, or water-level station in a more general sense, is the
geographic location at which tidal or water-level observations have been
made. The defining aspect of a tide station is the presence of a system of
(tidal) benchmarks, which are fixed physical objects (typically, deep-
driven rods) that serve as a reference for a vertical datum. The tidal
benchmarks are central to water-level measurement because the relation
between elevation of the land and water can be tracked through time, the
benchmarks providing the fixed reference (in the absence of subsidence or
crustal movement in general). Water-level measurement without reference
to benchmarks cannot produce recoverable tidal datums.

Chapter 2 Water Level Definition, Measurement, and Properties

Zoning

Zoning is a procedure in which the project area of a hydrographic
survey is divided into sections or “zones” to account for differences in
tidal ranges and phases within the area. In the hydrographic survey,
adjustments or “reducers” are applied to the depth soundings, which are
taken at all stages of the tide, to reference them to a common datum. The
correction must also allow for the time differences between the survey area
and the water-level gauge used for the control. Tidal zones are
distinguished by keeping two properties, range of tide and phase of tide,
within certain limits, typically 0.2 ft and 0.2 hr, respectively (Hicks 1989).
However, as stated by Hicks (1989), “these limits are subject to change,
depending upon survey accuracy, location, and tidal characteristics.” In
the case of Texas inland coastal waters, not only the astronomical tide, but
also wind forcing, must be considered in the zoning.

Character of the Tide Along the Texas Coast

Characteristics of the tide along much of the Gulf of Mexico are
different than those on the Atlantic Ocean and Pacific Ocean coasts. Even
within the Gulf of Mexico, tidal characteristics are variable from one
locality to another within short distances. Prior to the 1950s, there were
only a few locations where long-term tidal measurements had been made.
Although diurnal high and low waters occur only during the extreme north
and south declinations of the moon, the tides were classified as diurnal in
character. The mlw was therefore used as the reference datum for
hydrographic surveys.

As more systematic tidal observations were made in the coastal waters
of the Gulf of Mexico, it became evident that the classification of semi-
diurnal tides for the entire Gulf was not defensible. Although many areas
have two high and two low waters most of the time, there are nearby areas
where only one high and one low water occur. This observation led to the
creation of the Gulf Coast Low Water Datum (GCLWD) for the NOS
Nautical Charts. The GCLWD is defined as: mllw when the type of tide
is mixed, and mlw when the type of tide is diurnal. The National Tidal
Datum Convention of 1980 (Hicks 1980) established one uniform,

Chapter 2 Water Level Definition, Measurement, and Properties

13

14

continuous tidal datum system for all marine waters of the United States
and replaced the GCLWD by mllw, among several other actions.

Figures 2-7 are plots of the year-long hourly water-level records at
representative tide gauges on the Pacific, Atlantic, and Gulf coasts. These
include two inland coastal stations of Texas, the South Padre Island Coast
Guard Station located at the southern end of the Laguna Madre, and
Packery Channel located at the northern end of the Laguna Madre near its
entrance to Corpus Christi Bay. The figures are plotted to the mllw datum
of each station, and the respective values of mhw and mlw are given in the
upper right corners of the plots.

Figure 2 for Los Angeles, California, shows a clear signal of the
approximate 14-day neap and spring tide cycle corresponding to the
phases of the moon. By its definition as an average, there must be times
when the water level falls below mllw; for Los Angeles, this occurs at a
fairly regular periodic cycle corresponding to the times of spring tide,
when the moon is either new or full. Ships waiting to proceed into or
leave a port could consult tide predictions with reasonable confidence to
determine safe clearance under keel for a given draft according to load.
Overall, the water level at Los Angeles is fairly symmetric with respect to
the mtl. Little seasonal trend appears in the yearlong record.

Figures 3 and 4 show yearlong records for Sandy Hook, New Jersey,
and Fernandina, Florida. The water level is not as pronounced in spring-
neap cycle as is that of Los Angeles, in part due to the mixed character of
the tide and also to the action of storms on the gently sloping continental
shelf of the Atlantic coast as compared to the Pacific coast. Water level
falls below mllw in a somewhat less regular manner than at Los Angeles.
A slight seasonal trend of lower waters in winter is observed. For the
Atlantic- and Pacific-coast gauge records, the body of measurements stays
well and regularly within the mean range of tide defined by the mhw and
mlw lines drawn in the figures. At both locations, the deviation below
millw is typically 20 to 25 percent of the range.

In contrast to the Atlantic- and Pacific-coast water-level records, the
record from Bob Hall Pier, Corpus Christi, Texas, on the Gulf of Mexico
(Figure 5), is irregular, with the seasonal trend change in water elevation
comparable to or exceeding the daily change in tide. Further, the deviation

Chapter 2 Water Level Definition, Measurement, and Properties

below mllw is typically on the order of 50 percent of the range and
sometimes equals or approaches the range in 1995. Although a spring-
neap cycle is evident, local nonastronomical tidal forcing makes the cycle
appear irregular. Similar observations hold for the South Padre Island
Coast Guard Station gauge, which is located near the Brazos-Santiago
Pass and ship channel (Figure 6).

Figure 7 displays a year-long record for Packery Channel, which is
located just off the GIWW in Corpus Christi Bay, on the bay side of Padre
Island and nearly opposite to the Bob Hall tide gauge. Strong seasonality
in the water level is apparent, and, in 1995, the water level remained below
mllw for approximately 1 month starting in mid-January. Further, the
deviation in water level below mllw was typically equal to the mean range
of tide and even reached twice the mean range below mllw. This record
indicates a need for a navigation datum that accounts for seasonal lows
and that is not based on a simple average of daily water-level lows.

Chapter 2 Water Level Definition, Measurement, and Properties

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Chapter 2 Water Level Definition, Measurement, and Properties

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3 Present Water-Level
Measurement Networks
Along the Texas Coast

This chapter summarizes the status of TCOON water-level
measurement and of CESWG water-level measurement as practiced by its
field offices and hydrographic survey parties. The status is current to
September 1996, with some updates. The summary introduces basic
District operational needs as an outcome, which would include the needs
of Government contractors.

TCOON Capabilities

The TCOON presently consists of approximately 40 water-level
stations. On or near the coast, eight NOS gauges serve as long-term
control stations. Table Al in Appendix A summarizes the status of the
TCOON and NOS tide stations.

Present Galveston District Field Practice and
Identified Needs

The CES WG tide staffs are presently central to its hydrographic
surveys. Examples of two staffs are given in Figures 8 and 9. It is
standard procedure to take the survey boat to a tide staff to record water
level at the start of the day’s survey (typically early morning), mid-
morning, noon, mid-afternoon, and when quitting for the day. At the tide
staff, the survey boat will check its echo sounder and note the elevation of
the water on the staff and the time. In surveys of long channels, during a

Chapter 3 Present Networks Along the Texas Coast

typical survey day, the boat may have to visit several different tide staffs
located along the channel, depending on the rate of coverage of an area, or
station a survey crew member at the nearest staff to regularly report water
elevation via radio. A high density of staffs in some water bodies
probably reflects as much the need to reduce transit time to and from staff
visits as recognition that the water-level elevation changes along a water
body.

Boat visits to the staffs can consume substantial time in going off
station, remaining at the staff for several minutes, and then returning on
station. An operational problem sometimes encountered is difficulty in
visually reading the tide staff in moderate waves and wind, which can
cause trouble in keeping the boat stationary at the staff.

The tide staffs, which are typically mounted on timber survey
platforms, channel markers, bulkheads, etc., are routinely replaced as the
mounting structures are destroyed by barges or other vessels. Re-
installation of the staffs at the correct elevation often requires performance
of a level survey (if the tide station is near land or a survey table) or
knowledge of the water level based on a reading made at a nearby staff.
Figure 10 shows a staff being replaced by a Southern Area Office
surveyor.

In discussions with CES WG hydrographic survey party personnel,
several operational needs were identified. Survey boats could remain on
station and continue surveying if the operators could simply phone to a
gauge and obtain the water level. The information reported by the gauge
must be in standard units (feet, local time), and a repeat option should be
available because of occasional noise or loss of attention due to other
duties on the survey boat. The water level should be reported in terms of
the CESWG navigation datum (presently mtl), or a table for converting
from the reporting datum to the navigation datum should be provided (e.g.,
mllw to mlt).

Chapter 3 Present Networks Along the Texas Coast

23

24

Figure 8. Tide staff mounted on survey table at Channel to Victoria (see Staff 8,
Chart G, Appendix B). A dredging contractor's staff is mounted on the
third pile from left

Sees ti

Figure 9. Freeport Entrance Channel at the U.S. Coast Guard Station, Surfside
(see Staff 3, Chart E, Appendix B). The staff on the left is referenced to mit,
and the staff on the right is referenced to msl

Chapter 3 Present Networks Along the Texas Coast

— ee rm Se :
Figure 10. Staff being replaced at Fulton Harbor public boat ramp, Aransas Bay
(see Staff 5, Chart G, Appendix B)

At the office, the survey parties would benefit from ready availability
of a hard copy of the water-level record during the time they were onsite
for confirmation of the voice record and for documentation. The most
convenient way would be through facsimile; however, they would have
interest in downloading via the Internet, such as from a World Wide Web
(WWW) site, if they received training and equipment to do so.

In addition, the CESWG and its field offices are routinely asked to
provide water-level data or these offices themselves need water-level data
for varied reasons, including response and analysis of boating accidents
and responses to oil spills. Convenient access to hard copy or archived
data reaching back several months would usually satisfy most such needs.

Finally, interest was expressed in certain topics in related areas. A
primer (handbook) providing explanations of water levels and their inter-
relations was thought to be useful if not essential. The water-level
information should be given in local time and to the navigation datum, not,
say, to Greenwich Time or to an arbitrary staff datum that requires further
conversion. Information on wind and current, although not typically

Chapter 3 Present Networks Along the Texas Coast

25

26

entering directly in routine surveying operations, was sometimes needed
for evaluating claims of bad weather by dredging contractors and for
analyzing the circumstances concerning boating accidents.

In the offshore, information on wave height, period, and direction, as
well as water level, would be valuable for confirmation of weather days
that halt dredging. Dredgers sometimes appear to have to halt due to
longer period wave motions than just short-period surface waves; a wave
gauge might be able to determine the conditions when this problem
occurs. Finally, some interest was expressed in being able to obtain
predictions of the tide, both for planning routine operations and for
emergency planning during hurricanes and storms.

Locations of Galveston District Tide Staffs

After creating preliminary maps showing general locations of tide
staffs based on information provided by the CESWG Area Offices,
13 days of field reconnaissance were conducted during September and
October 1996, of the CESWG tide staffs from Port Arthur to Brownsville.
The locations (geographic coordinates and description) of the staffs were
determined by differential global positioning system (DGPS) or global
positioning system (GPS) survey, depending on satellite coverage at the
time the particular stations were visited.

A list of the locations of 166 CES WG tide staffs identified during the
survey is contained in Appendix B. In several cases, the tide staffs were
missing at the time of the survey, and station coordinates (for staffs to be
later replaced) were obtained based on knowledge of the former staff
location as provided by the Area Office field personnel who served as
guides during the field visits. Maps showing tide station locations were
generated as shown in Charts A-J in Chapter 5 and were designed to cover
areas of the coast corresponding to areas covered by specific NOAA
charts.

Chapter 3 Present Networks Along the Texas Coast

MLT and NGVD Difference

The differences between the mlt datum and NGVD 29 are listed in
Table 1, as provided by personnel of CESWG. Many of these differences

were determined in the 1960s and 1970s.

Table 1

| Watee Body (eta aa

| GIWW-Main Channel Port Arthur - High Island
I

| GIWW-Main Channel High Island — Bolivar
GIWW-Main Channel Galveston — Matagorda

GIWW-Main Channel Port Mansfield - Port Isabel

GIWW-Main Channel Matagorda - Port Mansfield
Sabine Neches Waterway Sabine — Orange

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[ GavestonBay Galveston Harbor — Texas City Chnl.

[crecosteBayou __——_—*| CheclteBayou Chama!
[sesvopsaveu _———=*di Basten Bayou tame |

BisosiRwen ccloradolRiver me River Floodgates - Colorado River

| Palacious - La Quinta Channel Palacious - La Quinta
Brazos Island Harbor Brazos Island Harbor — Brownsville
Port Isabel Port Isabel

Chapter 3 Present Networks Along the Texas Coast

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4 Communications
Alternatives

This chapter is concerned with communications alternatives for real-
time reporting and for access to archived data in a database. New
equipment and capabilities are constantly reaching the market, so an
existing-market search would need to be done at time of implementation.

Real-Time Reporting

Table 2 compares alternatives presently available for real-time voice
reporting of water level and related information. Certain instrument
manufacturers sell proprietary turnkey measurement systems that include
radio communication, which were not investigated here.

Table 2 solaldau Voie Rocco waists = 2 er).

| Features of Selected Voice-Reporting Systems

te
i | Minimal

Expandability [Moderate [| Minimal, — | Good
| Stand-alone or networked Stand Alone Stand Alone Networked

Cell/Land
Type of connection Cell/Land Phone eer ane leu, Cell/Land Phone Phone, Data
plus marine radio Radio

Voice vocabulary [Minimal [Moderate [Limited | Good
Voice quality [Minimal Good Good a Goce
[Voice speed |= Minimal [Moderate [| Moderate | Good _—

Fax, Text
| Fax or other medium Text Terminal Text Terminal Terminal,
| __ Graphics

Chapter 4 Communications Alternatives

Summary descriptions of the equipment are as follows:

Sutron board: Modular circuit board that plugs into any Sutron tide
gauge station. Access is via telephone. If the gauge is at a remote
location, a cellular phone with land line simulator is required.

Sphere reporter: Small external circuit connects to any Sutron tide
gauge via data port. Access is via telephone or marine radio. If the gauge
is at a remote location, a cellular phone with land line simulator is
required. The marine radio will provide a report automatically every 5 to
10 min on VHF Channel 13. The manufacturer is located in Australia, and
some difficulty was noted in provided changes in voice vocabulary;
however, the Sphere system appears to be very flexible.

Dialogic Netware: Centralized personal computer (PC) is used.
Users call this PC to hear high quality stored speech. The PC
communicates with tide gauges via a separate phone or by data radio. This
alternative is more costly than either the Sutron board or Sphere reporter,
but higher speech quality, alerting capabilities, etc., can be built in.
Altering the messages requires recording new phrases in a studio and
installing them on the system.

Voice Modem/UNIX: This is an evolution of the Dialogic Netware
system and is currently being actively developed at the Conrad Blucher
Institute (CBI) for its “FlowInfo” systems. Users call a central PC to hear
high-quality digitized speech. The PC communicates with tide gauges via
a separate phone or by data radio. Changes to the messages are
conveniently made by editing text files. Such changes may be done
locally or remotely via secure dial-in modem.

Recommendations and Costs

At present, the following recommendations are made, but should be
reviewed and revised prior to implementation. To access a particular tide
gauge via telephone, a Sutron board is recommended. If radio reporting is
desired, a Sphere reporter would be installed. To provide voice reports to
telephone callers from gauges in a particular area, installation of a
centralized PC is recommended. Currently, CBI would use the Voice

Chapter 4 Communications Alternatives

29

Modem/UNIX system. Table 3 gives estimates of costs of hardware and
labor, exclusive of labor for procurement, testing, and initial deployment.

| Table 3
| Estimated Cost of Stand-Alone (per gauge) Voice-Reporting Systems

[Phone | tavor | toal_|
Sutron Board $1,200 $250 (Land) $1,000 $2,450
Per minute fee

$1,200 $ 250 (Land) $1,000 $2,450 Monthly charges
sso | ll ig toe

Includes phone, batteries, solar panels, enclosure, antenna, landline simulator, etc.
Does not include overhead, handling, and other indirect costs.

‘Includes radio, antenna, batteries, solar panel, enclosure, antenna. Range is 5-10 miles per FCC rules.
?Radio may be added to a Sphere with either Land or CMT phone, or installed without either type of phone.

Remarks

Monthly charges

Centralized PC System:

Because of a wide variety of possible configurations, costs will vary
widely. A rough estimate of costs is as follows, not including indirect

costs:
Basic PC, speech hardware $4,000
Operating system FREE (LINUX)
Speech software $2,000
Basic installation $1,000
Phone company installation (3 lines) $ 750
Data radio system (to retrieve gauge data) $1,500
Total $9,250
(approximate)

Table 4 gives a listing of tide gauges possessing voice-reporting
capability as of 30 December 1996.

30 Chapter 4 Communications Alternatives

J

| Table 4
Gauges With Speech Capability, December 1996

[Mesquite Points| 87705391 | 409-781-9831 | 29.46.0°/ 9353.7" |
[ ChocolateBayou ——s|_ = 87717081_ ~—i|— 409-781-7195 | -2912.7'/95 12.4" |
| EaglePoint ss | «3S 877 10131_ _—i*| 409-656-4069 | 29:29.9'/94547' |
| AE RON ower nn NE el NS 77/097 HamrA09=781= 7193
[Morgan’sPoint ———s| =~ 87806131__—i|_——713-470-9739__|__2940.6'/9459.1_ |
[Beaumont ———s—S—S—=«dY=Cs=i 77 05951_—«| «409-656-2670 | 3005.7°/9405.4" |
Texas State Aquarium at ; ;
[Ingleside SC*dSC«877 283i |_—512-776-6934 | 27 49.3'/9712.5' |
[| PortAransas |S 87752371 512-815-4049 | 27 50.4'/ 9704.4" |

u

All gauges presently use the Sutron board and report water levels to mllw.

Access to Archived Data

Historic and daily data for the TCOON and NOS gauges in Texas may
be retrieved via the Internet using any standard WWW browser package.
The data are typically as recent as 3 hr old when received at CBI. Options
which may be selected by the user include: (a) data from previous week
for all sensors at a specified station; (b) any specified time period - days,
weeks, months, or years; and (c) multiple stations per graph to compare
tide signals. Other capabilities may be added on request.

CBI maintains an up-to-date list of Universal Resource Locators and
system capabilities. Two example screens are shown in Figures 11
and 12. Capabilities of the TCOON web page are constantly being
improved.

Chapter 4 Communications Alternatives

31

http://dco. cbi.tamucc.edu\ge

Texas Coastal Ocean Observation Network--Daily Quality Control

001: Naval Air Station
003: Rincon del San Jose
005: Packery Channel

006: Ingleside

007: El Toro Island

008: Texas State Aquaruum
009: Port Aransas

011: White Point

013: S. Bird Island

014: Bob Hall Pier

015: Rockport

016: Sabine Pass

017: Port Mansfield

018: Port Isabel

021: Galveston Pleasure Pier
022: Galveston Pier 21
028: Flower Garden

031: Seadnft

032: East Matagorda Bay
033: Port Lavaca

036: Copano Bay

047: Arroyo Colorado

051: S. Padre Island Coast Guard Sta.

054: Rawhings :

056: Freeport

057: Port O'Connor

058: Lavaca Bay

064: Backup for East Matagorda
066: Backup for El Toro Island

067: Backup for Arroyo Colorado
072: SALTO1

074: SALTO3
075: SALTO4
076: SALTO5
080: DOO

082: DO2

083: DO3

084: DO4
085: DOS
086:DO6
502: Clear Lak:
503: Morgans Point

Figure 11. TCOON quality control station list

504: Rainbow Bridge
505: Round Point

506: Mesquite Point
507: Eagle Point

508: Alteator Point

509: High Island

513: Manchester Houston
514: Beaumont

515: Orange

517: Lynchburg

518: Rollover Pass

519: Chocolate Bayou
520: Bastrop Bayou
521: Port Bolivar

522: Jetty

523: Sabine Offshore
524: Port Arthur

525: Galveston Offshore

Chapter 4 Communications Alternatives

| fj TCOON Quality Control Station #001: Naval Air. ternet Explorer
tant, st

rf,

ss http://dco.cbitamucc.edu/qe/001 /tomorrow,-15d/:qc:

Texas Coastal Ocean Observation Network--Daily Quality Control

TCOON #001: Naval Air Station

Previous (525: Galveston Main Next (003: Rincon del San
Notes
None

| DCP Statistics

001 97115 235905
001 97116 025905
001 97116 055905
001 97116 085905
i 001 97116 115905
001 97116 145905
001 97116 175905
i 001 97116 205905
i 001 97116 235905
001 97117 025905
i 001 97117 055905
i 001 97117 085905
001 97117 115905
001 97117 145905

NAaVAaLA 87754211 GOOD
NAVAL 87754211 GOOD
NAVALA 87754211 GOOD
NAVALA 87754211 GOOD
NAaVALA 87754211 GOOD
NAVALA 87754211 GOOD
NAVALA 87754211 GOOD
NAVALA 87754211 GOOD
NAVALA 87754211 GOOD
NaVALA 87754211 GOOD
NAaVALA 87754211 GOOD
NaVALA 87754211 GOOD
NAaVaLA 87754211 GOOD
NaVaLA 87754211 GOOD
NAVALA 87754211 GOOD
NAVALA 87754211 GOOD

OS3E 515 OK OK 13 S52 +0
OS3E 515 OK LOW 13 S2 -0O
O9S3E 515 OK LOW 13 S52 -0O
O93E 515 OK LOW 13 S2 -O
O93E 515 OK LOW 13 52 -1
OS3E 515 OK LOW 13 S2 -1
O93E 515 OK LOW 13 52 -1
O93E 515 OK LOW 13 53 -1
O93E 515 OK LOW 13 53 -1
O93E 515 OK LOW 13 52 -1
O93E 515 OK LOW 13 52 -1
OS3E 515 OK LOW 13 51 -1
O93E 515 OK LOW 13 51 -1
O93E 515 OK LOW 13 52 -1
O93E 515 OK LOW 13 52 -1
O93E 515 OK OK 13 52 -0

001 97117 175905
001 97117 205905

BEBRSSSESERSEe EE

Texas Coastal Ocean Observation Network printed 1997117+2142/UTC ij

ee ed
. . . . . . .
oh UH N DO OO DW

97104 97166 97108 97116 . 97112 97114 97116 O711E

Figure 12. TCOON quality control station 001: Naval Air Station

Chapter 4 Communications Alternatives 33

34

5 Consideration of an
Expanded Network

This chapter contains information for guiding future detailed planning
of the TCOON for CESWG needs.

Present Status of Network

The first step in designing a network is to obtain all historic data
available within the area of interest. This information has been obtained
and is summarized in Table 5. Maps, which follow in Figures 13-22,
show the locations of the gauges, as well as selected CES WG tide staffs.
A review of the historic data and the data from the TCOON system reveals
a lack of sufficient information for navigational or regulatory purposes for
several key areas. These are addressed in the final chapter giving
conclusions and recommendations.

Chapter 5 Consideration of an Expanded Network

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35

Chapter 5 Consideration of an Expanded Network

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Chapter 5 Consideration of an Expanded Network

36

|
|
|
|

Rainbows Bridge

© Tide Staff
© Active Sensor Statute Miles

Sabine Pass

© High Island
Gulf of

Mexico :

Legend

© Tide Staff
© Active Sensor

Statute Miles

Figure 14. Chart B (Includes NOAA Chart 11332)

Chapter 5 Consideration of an Expanded Network

37

Pasadena Statute Miles
>

Cypress
sak

Lynchburg

Turning\ Basin

Manchester Round Poin

Trinit
Bay

Rollover Pass

Legend

© Tide Staff
© Active Sensor

L777

Galveston Pleasure Pier

Gulf of

Mexico |

Legend

© Tide Staff
@ Active Sensor

Statute Miles

113523
Figure 16. Chart D (Includes NOAA Chart 11323)

38 Chapter 5 Consideration of an Expanded Network

CON
Chocolat
ocolate Bayoug

ov

[Churchill] ©

[Rivers End] ise
B az

Gulf of
Mexico

East Matagorda

Legend
© Tide Staff
© Active Sensor
[ J Historic

Statute Miles

po<Z_ £08018
[Palacios] Rawlings 2
16 g 8
Weta OReD BBY [SW E. Matagorda]
10
(Se EE LEE A a Gulf of
art .
VW ea VE Mexico
ZZ 4 ? Port O'Connor
V y
Yj Legend
¥ © Tide Staff
; © Active Sensor
e [ ] Historic
si Statute Miles
EE
z eee

Figure 18. Chart F (Includes NOAA Charts 11316, 11317, and 11319)

Chapter 5 Consideration of an Expanded Network

40

[Indian Head Point]

[False Live Oak]

Goose Island

Gulf of
Rockport Mexico

Legend

© Tide Stoff
© Active Sensor

[ Historic
Statute Miles

co
Lx Aransas

— [Sun Oil]

[Shamrock]
Navol Air

Station

Packery
Channel

Bob Hall Pier

Gulf of
Mexico

Bird Island
Legend

© Tide Staff
© Active Sensor
[ JHistoric

Statute Miles

Figure 20. Chart H (Includes NOAA Charts 11307 and 11308)

Chapter 5 Consideration of an Expanded Network

Yarborough
Pass

Gulf of
Mexico

El Toro

Rincon del
San Jose

Port Mansfield

Legend

© Tide Staff
05 © Active Sensor

Statute Miles

Arroyo Colorado

Gulf of
Mexico

Port Isabel

Brownsville Ship
Channel

© Tide Staff
© Active Sensor
[ ] Historic

Mexico

Figure 22. Chart J (Includes NOAA Charts 11301 and 11303)

Chapter 5 Consideration of an Expanded Network

41

42

Example of Need for Gauges

The inland bays and estuaries along the Texas coast are connected to
the Gulf of Mexico through narrow and, in some cases, shallow openings
in the barrier islands. As the tidal movement from the Gulf progresses
through these openings, it is diminished by the restrictions and by friction.
The astronomical force becomes weak compared to the strong
meteorological forces and is frequently masked and impossible to
consistently identify. The masking makes the computation of a tidal
datum difficult or impossible in the traditional manner. Kraus and
Militello (1996) document wind setup and setdown of water level on the
eastern and western ends of East Matagorda Bay, Texas, and found a
difference of 2 ft in water level at opposite ends of the bay produced by a
winter northern front, with 1-ft differences occurring almost weekly in
winter. The tidal range in East Matagorda Bay is only 0.4 ft.

Much of the area within the navigational waterways is nontidal, which
has been observed from historic data and existing TCOON stations (Gill,
Hubbard, and Dingle 1995). Where tidal datums cannot be determined,
stations will need to be spaced to determine and record variability in
elevations within each area. An example of such variability is shown in
Figure 11, which is a plot of simultaneous records from three stations in
the Land Cut in the Laguna Madre. The stations, going from north to
south, are Yarborough (004), EL Toro (007), and Rincon de San Jose
(003), which are located approximately 15 miles apart.

The horizontal axis plots time and covers a 2-day period. The vertical
axis represents the height of the water in feet. The three records are
plotted on the individual station datums or zeros, which are arbitrary and
have no direct height relationship between stations. The purpose of the
graph is to demonstrate how the water level changes between stations
within close proximity. The water level can be rising in one area, but
falling in another area just a few miles away. The downward pointing
spikes in the records are probably associated with the drawdown
accompanying the passage of barges. By associated pairs of spikes with
the passage of the same barge tow at El Toro and Rincon, the speed of the
barges can be estimated.

Chapter 5 Consideration of an Expanded Network

Water Level Data at 6-min Intervals
(10/17/96 through 10/18/96)

—»— Yarborough Pass (004)
Rincon del San Jose (003) |
—— EI Toro (007)

=~
2)
=
s
=
&
(a)
£
&
Ss
x,
=
<
&
=
©
>
&
Ww
~~
©
2
©
=

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46
Time, hr

Figure 23. Plot of simultaneous water-level records at three neighboring
nontidal stations along the GIWW

Establishment of Stations

Because of the variability in water-level change within short distances
along the shallow inland waters of Texas, numerous temporary gauges will
be needed for establishing requirements for long-term stations. The next
step in designing a network should be a detailed field reconnaissance to
determine suitable locations for short-term stations. Such a
reconnaissance may take on the order of a month and involve CESWG
Area Office personnel, as well as coordination with personnel overseeing
dredging operations and regulatory functions.

Short-term stations should be operated for a minimum of 30 days to
provide data for zoning the area. The requirement for the number and
location of long-term stations for navigation and regulatory support can
then be made.

To meet its specific needs during particular dredging operations, the
CESWG has in the past made water-level measurements and will continue
to do so. It is desirable that these project-level gauges be referenced to
benchmarks, and they must be referenced to the applicable NOS chart

Chapter 5 Consideration of an Expanded Network

datum. The sensors and associated equipment used to make the
measurements should meet the accuracy requirements of the USACE for
its dredging mission and conform as much as possible to the needs of other
agencies. There may well be several methods of acquiring reliable data.
We should always be cognizant of new developments in this field.
However, before introducing these procedures into the TCOON, reliability
and acceptability should be verified.

Chapter 5 Consideration of an Expanded Network

6 Conclusions and
Recommendations

A needs assessment was conducted to determine the requirements of
the CES WG, for water-level and associated information along the coast of
Texas, focusing on the inland coastal waters. The CESWG will use this
information in maintaining Federal navigable waterways, coastal
engineering, and environmental regulation in Texas. The assessment
included evaluation of the existing Federal and state infrastructures for
making water-level and wind measurements along the Texas coast,
relevant regulations and practices of the USACE and NOS, typical
projects and uses of water-level data by CES WG, and several anticipated
future needs of CESWG.

Main requirements of CES WG for water-level information and
recommendations are given below. The material is organized according to
individual subjects with the requirements and recommendations developed
from the information and findings described in the main text and
appendices of this report.

Federal and State Cooperation (Backbone
Network)

An excellent network of water-level and wind measurement stations
exists along the Texas coast that has been primarily supported by the
TGLO and the TWDB. It is recommended that the CES WG join these
state agencies and other users of the TCOON in supporting and improving
the network, and in prioritizing its activities according to common needs.
A TCOON Steering Committee, formed of representatives from Federal
and state agencies contributing financial support for the network, now

Chapter 6 Conclusions and Recommendations

45

46

meets periodically throughout the year to review performance and quality
of products, set priorities, apportion funds, and plan future work. In
formulation of a backbone network with shared resources, priority in
allocation of resources is decided by the Steering Committee members to
minimize imbalances in benefits.

The backbone network is a collection of stations and capabilities that
meets the common needs of all member agencies of the TCOON Steering
Committee. Table 6, located at the end of this chapter, gives guidance on
those water-level stations recommended for support of CESWG
requirements as part of the backbone network. Existing and recommended
future stations are listed in the table. Table 6 integrates much of the work
conducted in this study.

Real-Time Voice Reporting

Up to 1996, the TCOON had existed primarily to provide information
for three purposes. These are: (a) dealing with boundary issues between
the state and private-property owners, (b) operating the state’s numerical
simulation models of water circulation and water quality, and (c) operating
the state’s soil-spill fate numerical simulation model (presently obtaining
wind data in near-real time via the internet). Reporting of water level is of
highest priority, followed by provision of wind speed and direction
reporting at selected stations.

Past state-related functions of the TCOON have rarely required real-
time data voice reporting. However, real-time voice reporting is
considered an essential part of a backbone network designed to meet
operational needs of CESWG. Real-time reporting will benefit agencies
involved with oil-spill prevention and response, as well as Federal, state,
and local agencies faced with decisions on hurricane-response evacuation.
Other beneficiaries of real-time voice reporting would be the U.S. Coast
Guard, waterways transportation industries of various kinds (such as ports
and barge operators), environmental interests, and academic research and
education programs. A portion of the backbone network funding should,
therefore, be identified for staged introduction of real-time reporting
according to priorities set by the TCOON Steering Committee.

Chapter 6 Conclusions and Recommendations

Voice reporting should satisfy at least five requirements. Information
should be: (a) available in near-real time (for example, refresh rate of
15 min); (b) given in engineering units (presently, feet); (c) referenced to
chart datum; (d) easily repeated by telephonic or radio command, without
having to redial; and (e) obtainable the day after original interrogation for
verification and archival in project files.

Voice reporting may be by telephone (land line or cellular) or by radio.

However, provision should be made to allow priority access by the
TCOON Steering Committee agencies, as distinguished from possible
access by other agencies and the general public.

Training of Galveston District Personnel

A training program and materials should be developed for CESWG
Area Office and other personnel who will require the real-time and
archived data. The training would include such topics as review of tidal
datums and relations to District project low-water datums (see next
section), review of previous datums used by CESWG and their relation to
present-day datums, elements of the forces producing water-level change,
properties of water-level change along the coast, practical aspects of
communication with the gauges, and use of the WWW with associated
data downloading and printing of graphs and tables. Without orientation
and special training of its personnel, the CES WG will not obtain
maximum benefit from participation in the TCOON.

Project Low-Water Datums

Much of the inland coastal waters of Texas, which are traversed by
several hundred miles of maintained navigable channels, experiences
water-level variations that are not well quantified by traditional NOS
methods of datum determination. Seasonal changes in water level as well
as wind setup and setdown can obscure or dominate tidal induced water-
level signals. As a result, water level drops considerably below chart
datum (mllw, mlw, or msl, depending on the chart) for considerable time
(order of several days).

Chapter 6 Conclusions and Recommendations

47

48

Therefore, for assuring safe navigation, we recommend that the
CESWG develop project low-water datums based on water-level
observations. The project low-water datums, specific to certain locales
depending on the known properties of the water level variation, would be
referenced to an existing NOS chart datum, if available. A specialized
effort needs to be implemented to develop rational and defensible project
low-water datums. That is, project low-water datums should be based on
observation and sound procedures, and the determined values should not
be unreasonably conservative, thereby causing unnecessary dredging.

Engineering Utility of Archived Data

The existing WWW internet site (http://dco.cbi.tamucc.edu/data) for
accessing TCOON data is a sound basic system. Data loaded to the site
may be as recent as 3 hr old. Lists of data and plots can be generated by
command for arbitrary time intervals, and the queried information can be
downloaded.

Presently, the data are reported to the (arbitrary) local staff zero, called
the “datum of tabulation.” The datum of tabulation remains constant
through the life of a station (even if the physical gauge is removed, later to
be replaced) and is one of the key procedures in the process of relating
water level to fixed benchmarks on land. However, the datum of
tabulation is arbitrary and not, of itself, physically meaningful. Two
enhancements to the WWW site need to be made for applications of the
data by the CESWG and its contractors. These enhancements will also be
valuable for any engineering or scientific study or project.

First, the WWW site should provide the relation between staff zero and
the mllw datum (or msl if mllw cannot be defined, as in nontidal waters)
and an option given to plot the data to mllw or msl. This capability can be
added with little effort. Second, all tidal datums available for the
individual stations should be accessible. Other datums, such as mhw and
msl, enter in regulatory functions and environmental modeling conducted
by the CESWG and its contractors. Extreme high- and low-water levels
contained in the record, as well as the tidal range, should be given. As
much as possible, and in coordination with NOS, the tidal datums should
be computed to the most recent 19-year interval if the NTDE is not

Chapter 6 Conclusions and Recommendations

updated to modern time. This second capability will require some effort,
but could be accomplished within a calendar year.

Project-Specific Operational Gauges

The backbone network, described in Recommendation 1 and in
Table 6, is the system of long-term gauges and selected short-term gauges
that serve as primary references and furnish continuous records. The
backbone network serves the common need of all TCOON Steering
Committee member agencies.

The CESWG has its own specific needs for short-term water-level
measurement and reporting at the project level. Such a project might have
duration on the order of 1 to 6 months. Voice-reporting project-specific
gauges would greatly reduce cost and improve reliability in performing
reconnaissance surveys, project-condition surveys, contract-payment
surveys, and surveys made during the course of dredging in navigable
channels and waterways. The minimum number of operational gauges
necessary can be determined through the process of reconnaissance and
tidal zoning as described in this report. Typically, one to three short-term
project gauges might be necessary if gauges from the backbone network
augment their capability.

As part of a long-term plan, permanent or semi-permanent platforms or
mounting areas must be constructed and maintained. The platforms
should be designed such that a permanent vertical elevation can be
identified, allowing the water level measured at the project-specific gauges
to be tied to the NOS datum applicable to those waters.

Project-specific water-level gauges need not be to the same high
accuracy as backbone gauges that have the function of making
measurements to determine traditional tidal datums. Backbone gauges
employ equipment and procedures to assure overall accuracy on the order
of a few millimeters. The function of project-specific gauges is to control
soundings taken in maintenance of navigation channels. In project-related
hydrographic surveys made in water depths of 10 to 25 ft, for example,
sounding equipment and procedures are expected to have total-system
accuracy of + 0.2 to +0.5 ft (USACE 1991), depending on sea state and

Chapter 6 Conclusions and Recommendations

49

50

texture of the bottom sediments, among other variables. Therefore, it is
appropriate to require project-specific water-level gauges to be accurate to
+ 0.1 to + 0.2 ft, depending on environmental conditions at the site and
distance to the nearest backbone gauge. Such accuracy may be
economically achievable with DGPS technology, but this technology must
be tested.

In addition to documented and verifiable surveying procedures,
calibration records on the water-level instruments or sensors should be
kept. It is recommended that, for Texas inland coastal waters, self-
contained pressure gauges with radio transmission capability be
investigated for fulfilling requirements of project-specific operational
water-level gauges.

Data stored in or transmitted from the project gauges should be
compatible with TCOON standards, for example, as an average taken over
a 6-min interval. The data should be incorporated in the TCOON
database, together with the associated local reference elevation of the
platform and other essential information that will allow re-establishment
of the “project station” and access by interested parties. If measurements
made to meet project-level requirements have greater tolerances or
reliability than backbone gauges, the accuracy range of the values in the
database should be provided as part of the information given with the raw
or processed data.

Outside (Gulf-side) Gauges and Wave
Measurement

The capabilities of dredging and navigating in a channel or waterway
depend on sea state (surface wave height, period, and direction), as well as
on absolute water depth. Measurement of sea state is particularly pertinent
in entrance channels and in the offshore of deep-draft channels. Individual
surface waves (typical periods of 5 to 10 sec) as well as longer period
swell (typical period of 30 to 60 sec) can disrupt or halt dredging
operations and make navigation unsafe. Real-time voice reporting and
documentation of sea state could be incorporated into dredging operations
to make them more efficient, as well as make navigation safer.

Chapter 6 Conclusions and Recommendations

Wave height and period can be measured with pressure gauges. Such
gauges can also report water-level variations. Vertical and horizontal
position of the gauges may be determined for support of dredging
operations with sufficient accuracy through DGPS survey.

Investigation of DGPS

Many of the inland coastal waters of Texas are nontidal according to
traditional NOS determinations. Therefore, a reference for navigational
purposes other than mllw must be used. Because interconnection of the
stations through conventional differential levels is not feasible, surveying
by vertical as well as horizontal DGPS procedures should be considered,
with due regard to verification of stated accuracy.

Chapter 6 Conclusions and Recommendations

51

52

Table 6

| Recommended Long-Term Water-Level Stations (Backbone Network) and
Required Short-Term Stations to Fill in Gaps for Support of USACE

| Operations

NOS Station No.
Station Name 877- Comments |

NOS Chart Numbers 11332, 11342
Sabine Pass, Sabine Lake, Port Arthur :

['SabinePass «05701 ~‘| NOSlongtermstation
eRe ieee nator.
H evaluation
| Highisland Cid SC0923 | Lowwatters being cutoff, gauge mustbemoved |
Rae en mei |
| NOS Chart Numbers 11323, 11326, 11327, 11328
Galveston Entrance, Galveston Bay, Houston Ship Channel
Ca PT |
| Galveston Pier21_—s | 14501 | NOSlong-termstation
[ GalvestonBay entrance | tate 1 [ee
PointBolivar 2 328 lla eek ow sore ile hs
pEageiRont 7 ees | 01st a eee
Clear Lake Uncertain if this station is necessary — needs detailed

pynchburgikandings |. 0733 a a
jMorganisiRoint a8 006134 ey
MRotind Point stare, 0559 |

NOS Chart Numbers 11316, 11319, 11321, 11322 |
| Freeport, East Matagorda Bay, Colorado River |
[Freeport CTS 24401 ~~ | NOSlongtermstation =
| East Matagorda 2 |.) 30081 |
| p Recommended placing long-term gauge at confluence of

| Colorado River Navigation Channel, Matagorda Bay, Espiritu Santo Bay
[Rawings
Channel Entrance Station, then remove
Mouth of Colorado River
Navigation Channel

If maintenance of the CR Navigation Channel will continue,
Entrance of GIWW land
cut to Matagorda Bay

a ee |

then recommend installation of open-Gulf station on the
north jetty and removal of Rawlings

Establish short-term station to determine tidal
characteristics in central portion of bay and compare to
Port O’Conner and Port Lavaca stations

Establish station on bay side of the ship channel and
compare to Port O'Conner to determine differences; if
similar characteristics, remove Matagorda Ship Channel
gauge and retain Port O'Conner gauge

Matagorda Ship Channel

short- or long-term station

3259 1
Port O’Conner 3701 0

Espiritu Santo Bay short-
term station
} Victoria Barge Canal long-

|_term station

Establish short-term station to determine tidal
characteristics between Port O’Conner and San Antonio
Bay

i
Establish station reporting water level and wind |

(Continued)

Chapter 6 Conclusions and Recommendations

\
jj

| Table 6 (Concluded)

ts
if

NOS Station ia ten
No. 877- Comments |

NOS Chart Numbers 11313, 11314

San Antonio Bay, Aransas Bay
Establish station in San Antonio and determine whether it
should be long-term based on tidal characteristics and
dredging operation needs

Station Name

| San Antonio Bay — Short-
| term or long-term station

4513 0
4770 1 NOS long-term station

NOS Chart Numbers 11308, 11309
Corpus Christi Bay, Corpus Christi Ship Channel

Copano Bay
|_ Rockport

— |

| PortAransas «| ~SS«823871 _—| AdjacenttoCorpusChristiShipChannel
Port Ingleside eet | Not strictly necessary, but has solid infrastructure; also, is

| near intersection of GIWW and CC Ship Channel
[Texas StateAquarum | 52961 ‘| Nearthe Corpus Christiharborentrance
| CC NavalAirStation ss [| 54211 | TeststationforTCOON es C‘CSCir
[iPackery! Channelines.seib ane OTO2Mes 40 eR ee ane
| NOS Chart Number 11307

Corpus Christi Bay, Upper Laguna Madre, Baffin Bay
NOS long-term open-Gulf station

——t

| Corpus Christi, Bob Hall

: 5870 1 1
Pier H
South Bird Island 6139 1 Marginally tidal |

Establish two or three short-term stations between South
Bird Island (marginally tidal) and Yarborough Pass (Baffin
Bay) (nontidal) to determine tidal characteristics along the

NOS Chart Numbers 11304, 11306, 11308
| GIWW Land Cut, Port Mansfield oy |

| Short-term stations

Yarborough Pass 6687 1 EOUCELAISSE TVS ao a oe)
7562 1 Nostale Sle: 3s a abd oe eal |
Rincon del San Jose 7812 1 HNontidal Sigaeew tee rector Oe he tem Ae

| Establish one or two short-term stations between Rincon

| Short-term stations ieee and Port Mansfield stations to determine tidal
characteristics between the two locations H

| PortMansfield | 84901 | NOS long-termstation; nontidal Cd

jl NOS Chart Number 11301

Arroyo Colorado, Lower Laguna Madre, Brownsville Ship Channel, Port Isabel |

i WATTS VO! CClGr ado Naina mn | se OO 381M ra im (NG riticallulmaatne its ie ees Se eT)

Establish two or three short-term stations between Arroyo |
Colorado (nontidal) and the Port Isabel & SPI-CG (tidal)
stations to determine tidal characteristics along the

Short-term stations

GIWW
| Port Isabel 9770 1 Long-term NOS gauge H

ee ahs pase 9748 1 Near Brazos Santiago Ship Channel and jetties |
onotem penueion | | If Cameron County rebuilds a fishing pier at South Padre
| Long-term open Gulf station Island, re-establish a long-term Gulf station for dredging |
operations at Brazos Santiago Entrance Channel |

Chapter 6 Conclusions and Recommendations

53

References

Gill, S. K., Hubbard, J. R., and Dingle, G. (1995). “Tidal characteristics
and datums of the Laguna Madre, Texas,” NOAA Technical
Memorandum NOS OES 008, National Oceanic and Atmospheric
Administration, National Ocean Service, Silver Spring, MD.

Harris, D. L. (1981). “Tides and tidal datums in the United States,”
Special Report 7, U.S. Army Engineer Waterways Experiment Station,
Coastal and Hydraulics Laboratory, U.S. Government Printing Office,
Washington, DC.

Hicks, S. D. (1980). “ The National Tidal Datum Convention of 1980,”
NOAA S/T 80-177, National Oceanic and Atmospheric
Administration, National Ocean Service, Silver Spring, MD.

. (1985). “Tidal datums and their uses — a summary,” Shore
& Beach, January, 27-32.

. (1986). “Tidal datums and their uses — a summary,” The
Hydrographic Journal 39, 17-20.

. (1989). “Tide and current glossary,” National Ocean
Service, National Oceanic and Atmospheric Administration, Rockville,
MD.

Hydrographic Manual. 1976. (4" ed.). National Oceanic and Atmospheric
Administration, National Ocean Service, Rockville, MD.

Kraus, N. C. and Militello, A. (1996). “Hydraulic feasibility of proposed
southwest corner cut, East Matagorda Bay, Texas,” Technical Report
TAMU-CC-CBI-96-03, Conrad Blucher Institute for Surveying and
Science, Texas A&M University-Corpus Christi.

Lyles, S. D., Hickman, L. E., Jr., and Debaugh, H. A., Jr. (1988). “Sea
level variations for the United States 1855 — 1986,” National Oceanic
and Atmospheric Administration, National Ocean Service, Rockville,
MD.

54 References

Michaud, P. R., Thurlow, C. I., and Jeffress, G. A. (1995). “Collection
and dissemination of marine information from the Texas Coastal
Ocean Observation network. Proceedings, U.S. Hydrographic
Conference. Hydrographic Society Special Publication No. 32, 168-
iW73:

National Oceanic and Atmospheric Administration. (1977).
Establishment of gulf coast low water datum,” Federal Register 42
(179), 46381-46382.

. (1990). “Index of tide stations, United States of America
and miscellaneous other locations,” Ocean and Lake Levels Division,
National Ocean Service, Rockville, MD.

National Research Council. (1987). Responding to changes in sea level:
Engineering implications. Marine Board, National Academy of
Science, Washington, DC.

Shalowitz, A. L. (1964). Shore and sea boundaries. Publication 10-1 (2
Vol), U.S. Coast and Geodetic Survey, U.S. Government Printing
Office, Washington, DC.

Shore protection manual. (1984). (4" ed., 2 Vol), U.S. Army Engineer
Waterways Experiment Station, U.S. Government Printing Office,
Washington, DC.

Swanson, R. L., and Thurlow, C. I. (1973). “Recent subsidence rates
along the Texas and Louisiana coasts as determined from tide
measurements,” Journal of Geophysical Research 78(15), 2665-2671.

U.S. Army Corps of Engineers. (1989). “Water levels and wave heights
for coastal engineering design,” Engineer Manual 1110-2-1414,
Washington, DC.

. (1991). “Hydrographic surveying.” Engineer Manual 1110-
2-1003, Washington, DC.

. (1993). “Requirements and procedures for referencing
coastal navigation projects to mean lower low water datum,” Engineer
Technical Letter 1110-2-349, Washington, DC.

. (1994). “Conversion to the North American Vertical Datum
of 1988,” Engineer Technical Letter 1110-1-152, Washington, DC.

References

55

= es -

Appendix A

Locations and Capabilities of
TCOON Stations, September
1996

Appendix A Locations and Capabilities of TCOON Stations, September 1996

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Appendix A Locations and Capabilities of TCOON Stations, September 1996

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Appendix A Locations and Capabilities of TCOON Stations, September 1996

A4

Appendix B
Locations of Galveston District

Tide Staffs, September 1996

Appendix B Locations of Galveston District Tide Staffs, September 1996

Bi

B2

Table B1 a
Locations of USACE — Galveston District Tide Staffs
MLT Ft

Location Lat/Long Below
So Be

Chart A (Includes NOAA Charts 11342 and 11343) :
ES
fnew |e emo [eae
uk Sh pce ee el 29° 47 35.45" Saal ee on timber pile along
water barrier 94° 00’ 36.19) eal es bank
[tame | A [Hwezenve | © Sieasare eed
fase [oe [oem [Saar | [arene
jctamet | A? [Shama | esr ane
} Channel Channel 93° 57’ 42.2 Bridge on range marker
eoian| ee eee =o
oe aa
Esa ia
feownw [0 [Maui | Bone
|
pcote [ws [Setumnas, | Sue
[eenesiver | A16 | Resene doce | sacar tae
ES oe ee
fone [ne [owes [ata
[css eo eee | ee
eceront nl even |isvsee | | Scac aal
[seonetate | az [westrass | Seearcose | MA | stousontonsnere |
(Sheet 1 of f 8) I
NGVD relationships from table provided by Lynwood Weiss, USACE, Galveston District, dated |

|

| Notes:

March 22, 1990.
NOS Standard Chart numbers used.
** Estimated from chart.

Appendix B Locations of Galveston District Tide Staffs, September 1996

[ Table B1 (Continued)
a)

|
|

MLT Ft
Location Lat/Long Below Comments
NGVD
Chart A (Includes NOAA Charts 11342 and 11343) (Continued) |
| Saacrer 2m ae 30° 02’ 14.89” ; 7)
| Sabine River | A22_ Sabine Pipeline 93° 44’ 21.51” Staff on timber bulkhead
: : 30° 03’ 48.74” East of Adams Bayou; staff
| Sabine River | 423 | PON GICTenge 93° 43’ 12.69” on small wooden pier
t 5 = =
. : 30° 04’ 46.88 Staff on timber bulkhead at

30° 05’ 04.52” Staff on timber bulkhead
93° 43° 27.83” near American Bridge
3 shipyard rear dock

N/A
Near intersection of 29° 50’ 36.8” : :
Taylor Bayou | 426 | GIWW and Port Arthur 93° 58° 13.0" N/A ay Metal Bec ser |
angi est Ship Canal |
, , 30° 01° 04.72” |
North of Black Bayou 93° 44’ 51.37” Staff on red day marker 8 |
| West of Sabine River at 30° 02’ 14.42” Staff on cluster of mooring
Chart B (Includes NOAA Chart 11332)
Jetty Channel ey W. front range light 2944 9340 ae WSUS! CIAL)
| Pilot Station at Texas 29° 41’ 11.69” Staff on pilot boat dock
| Sabine Pass ; ™ 29° 43' (Staff not visited during |
| Sabine Pass 29° 43’ 46.33”
eee | ee U.S. Coast Guard 93° 52’ 14.62” Staff on timber dock
| Giww NE of marker 315 at 29° 37’ 56.70” 94° N/A Staff at abandoned house
Barnes Slough 18’ 18.00” on south bank of GIWW st

GIWW-south bank / State
| - 29° 36’ 12.20” 94°
GIWW Near High Island 24° 55.12”

Hwy 124, AT&SF Railway
29° 35’ 41.24” Staff on small pier about !
om At State Hiwy..124 94° 23' 25,26" 200 yd from bridge
ye : Staff on timber bulkhead at |
GIWW B8 NW of Clam Lake a a seek N/A south bank (Sonat
94° 07' 27.26 5 |
Exploration Company)
Chart C (Includes NOAA Charts 11326 and 11329)
| GiMww- baa ee 29° 31’ 27.8” At Rollover Pass; staff on
| Gilchrist OtiFeggard's Slip Roady 1 g4eo9v11i7" south bank of GIWW
Houston Ship ; 29° 45’ 20.63”
Near Battleship Texas 95° 05' 27.05” N/A Staff on bulkhead at park |
** 29° 3.4’ (Staff not visited during |
| Trinity River | C4 | Trinity River Channel mae = At Smith Point near ramp |
C5

#990 45' Near Live Oak Bay &
GIWW Junction Canoe Creek 95° 45) N/A Boggy Bayou, south of H
Sargent H
| Near State Hwy 562 & |
pest Beebo ** 29° 46’
| Trinity River C6 Trinity River Channel 94° 45'

Sabine River A25 | Near Phoenix Lake
i}

--t PE *

bridge (destroyed); staff on
timber pile

Sykes Rd.; Round Point,
north of Ash Point, near
channel to Liberty

(Sheet 2 of 8) |

Appendix B Locations of Galveston District Tide Staffs, September 1996

B3

B4

| Table B1 (Continued)

= 5 MLT Ft
ae Location Lat/Long Below
ey NGVD

Chart C (Includes NOAA Charts 11326 and 11329) (Continued)

| Houston Ship At green channel marker 29° 44’ 17.03” NA
Channel 139 95° 06’ 55.49”

; South bank of channel n
| Houston Ship 29° 44’ 48.11
ridge
Houston Ship C9 Near Green’s Bayou and 29° 45’ 11.0” NIA
Channel Todd’s Ship Yard 95° 10’ 31.4”
Houston Ship C10 At Tessondlo Kerley 29° 44’ 55.54” NIA
Channel plant 95° 11’ 08.80”
Houston Ship : : 29° 40’ 56.7”
Channel At Morgan’s Point 94° 59’ 02.7" N/A Near Barbour’s Cut
Houston Ship Near Spilmans Isl. on 29° 42’ 5.0”
Smal [ 60 [newamonwrnine [Stress [NA [eraeunat™
Sal | o [newonemsoren [a fee
Houston Ship C15 Near Battleship Texas . 29° 45’ 33.22” NA lear green channel marker |
| Channel Monument 95° 05’ 21.97”
Clear Creek Galveston Bay/Clear *"'29°133) NVA (Staff not visited during
} Channel Creek 95° 01’ survey)
| Bayport Ship Bayport/Houston ='29° 37° NA (Staff not visited during
f Channel Channel junction 95° 01’ survey)
GIWW - High Approx. station 1800+00 N/A N/A Staff on navigation range
}_ Island in GIWW
Houston Ship At Mobile Mining Plant 29° 44’ 19.8” NA
} Channel near Hunting Bayou 95° 11’ 44.76”
Houston Ship At San Jacinto Mill 29° 43’ 27.02”
| Channel 95° 12’ 54.20” N/A Staff on green marker 163
| Houston Ship At U.S. Coast Guard 29° 43’ 27.02” :
| Channel 95° 12’ 54.20” N/A Near Loop 610 bridge
i Houston Ship : 29° 44’ 57.4”
Bayport at Houston 29° 37’ 13.8” N/A
Yacht Club 94° 59° 52.5”
Chart D (Includes NOAA Chart 11323)
ney 5 Approx. 6 to 7 mi. east of
Near Caranchua Point a S ese 1.41 Chocolate Bay; about 1000
: j ft east of marker 370
At Stingaree Restaurant a a se N/A See eat mht
Pees 29° 22’ 02.00” Staff on north side of dike
SIG MIEEOE VIS | ep an einep 1-41 | about 20 ft from dike
Through Pelican Isl. (at 29° 20’ 59.6”
Pelican Spit) 94° 49’ 09.9” N/A Staff near north bank
: 29° 19’ 12.07”
Galveston Yacht Basin 94° 46’ 38.29” 1.41

Comments

4

= =
= (on)
=

Houston Ship
| Channel

C16
C17
C18
C19
C20
C21
C22

23

Cc

i
!
= ——-4tL__

Off Shoreacres Road

GIWW - West

| GIWW- High
Island
| Texas City SC

| GIWW Main
} Chol.

| Galveston SC

ft)
<

: 29° 18° 45.06” Staff on timber pile cluster _|

Galveston SC At Pelican Is!. Causeway 94° 49° 28.91” 1.41 on south side of causeway |
: Range Platform at end 29° 21’ 55.42” Staff on south side of

Tere Ci oe D7 aillofitexas\CiyiDike 94° 48° 53.24” 141 | (about 40 ft from) dike |

(Sheet 3 of 8) |

Appendix B Locations of Galveston District Tide Staffs, September 1996

| Table B1 (Continued)

MLT Ft : |
Location Lat/Long Below Comments H
NGVD a Paice aio

Chart D (Includes NOAA Chart 11323) (Continued)

! Causeway Fish Camp 29° 17’ 21.6”
sc | pe | usaceb tb 29°02 SOL Staff on timber pile
Galveston oat basin 94° 46’ 25.36" 4 p

p 2 Staff at 1% ramp (from
At Texas City Dike 29° 22’ 58.1
Texas City SC = (south side) 94° 51’ 50.5" 1.41 ea on south side of
Eastern terminus of 29° 21' 37" Damaged staff - does not
| Houston Sc Bolivar Peninsula (at OVA ECD match elevation reading at
: 94° 46° 56
ferry landing)
Sh N 130+00 at 29° 25' 51.0" This staff replaced the staff |
Bolivar D12 ear Stn 3 ‘ a d is staff replaced the sta
Shirley's Bait Camp 94° 42’ 35.0” at 237 Canal

nearest staff
Peninsula

eres D13 At Seiver's Cove (yacht 29° 25’ 51.0” At Shirley's Blue Beacon |
: basin) near Stn 2878+00 94° 42’ 35.0” Bait Camp

}_ Peninsula H
Sd Ww | Road 29° 28' 07.7” Tide staff has b

Bolivar D14 lest Canal Road near . ide staff has been missing | |
f = Stn 2622+00 94° 38’ 34.6” for approx. past year
| Peninsula
H Eagle Point Marina at 29° 29’ 47.7” |
Houston SC 94° 54’ 39.0” Staff at East Bay shore |

Chart E (Includes NOAA Charts 11321 and 11322)

| 29° 10’ 28.43”

Chocolate Bay [= | Staff on range marker 95° 08' 5.85” N/A

| GIWW - aan 2

Chocolate E2 Near Alligator Point Ae an aoe N/A green day marker 1; south

| Bayou : bank of GIWW.

| Freeport : 5

North bank of Surfside 28° 56’ 37.06
Entrance Coast Guard Station 95° 18’ 08.95” N/A Staff on concrete bulkhead
Channel

| Freeport |e | Tumin — 28° 56’ 25.15” (Staff missing at time of
Harbor g 95° 20’ 30.32” survey)

eee Quintana swing 28° 55’ 17.68”

: s ** 28° 52’ (Staff not visited during

| Giww-san | _ | SanBemard River 28° 52 11.74" Pp pea a a sabe
Bernard River crossing at GIWW 95° 26’ 47.47” agi ae tape cseaa
old bait camp !
survey); will be mounted on
| : ; 2 Staff near Bay Avenue
GIWW - Public boat ramp #16 at 28° 58’ 49.47

f On north bank of GIWW at
GIWW - Cedar 28° 50’ 26.71” 3
(oa North of Sargent Beach 95° 31’ 09.28” Wee 410 (staff on
a 2x 8 in board near north
GIWW - (Staff not visited during

Hl (Staff missing at time of
| GIWW - Cedar 28° 49’ 45.52”
ges North of Sargent Beach 95° 32’ 07.48” N/A
bank
(Sheet 4 of a) |

East of marker 375 at

Appendix B Locations of Galveston District Tide Staffs, September 1996

BS

B6

| Table B1 (Continued)

MLT Ft i.
| Waterway Location Lat/Long Below Comments
| NGVD ioe
Chart E (Includes NOAA Charts 11321 and 11322) (Continued)
Freeport 28° 56’ 15.97” N/A Staff on timber pile at dock
Entrance E11 shail Chel GuSesn 95° 18° 03.46” Bhi
Channel J
: . 28° 53’ 47.59” N/A At USACE boathouse,
si le cpm (A (=e eae Cea ata || WCAC approx. Stn 2414600,
| neearcehn GIWW north bank
GIWW - E13 Brazos River flood- 28° 53’ 43.80” N/A On north bank of GIWW.
| Brazos River gates, west side 95° 23’ 22.66”
| GIWW— F F 28° 46’ 17.15” N/A 8-ft wooden staff on pile
Beare Saigenteming Budge 95° 37’ 01.73” ara cluster at end of short pier
| GIW - Live ; ; 28° 45’ 00.78” N/A East bank of Live Oak
Z : 28° 44’ 17.00” N/A Staff in board pounded into
See geek Sil of Big Boggy | 95° 49° 37.89” channel bottom about 40 ft
ggy bay y from north bank
Chocolate Near Grassy Point on 29° 11’ 35.3” 1.37 Across from red channel
E17 | abandoned Coast Guard 95° 09’ 00.8” marker 20
eayeou range
Chocolate E18 On abandoned Coast 29° 12’ 05.3” 1.37 Near red day marker 34
Bayou Guard range 95° 10’ 28.2”
Chocolate F 29° 12’ 41.1” 1.37 Staff on west bank on boat

Chart F (Includes NOAA Charts 11316, 11317, and 11319) f

U.S. Parks and Wildlife : a ee Ne N. Staff on concrete bulkhead
Office :
; 28° 41’ 41.35” N/ Staff on survey table
Near Palacios Harbor 96° 13° 34.42” beat
N/

| GIWW- Port
| O’Conner

Channel to
Palacios
Channel to
! Red Bluff

GI -
Matagorda

At railroad bridge near 28° 49’ 53.95” N/A (Staff missing at time of
Hwy 616 bridge 96° 34’ 41.23” survey)

1000 ft east of 28° 41’ 33.40” East of 440 mi. marker;
Matagorda Harbor 95° 57’ 06.49” staff on mooring pile
entrance cluster

A
A
A
28° 43° 00.98" N/A | North bank of GWWon |
eB icut rant 95° 53° 23.75” feos ie damaged timber dock _|

TA

IA

TA

A

| GIWW - 28° 41’ 13.12” Staff on timber platform — |
| Colorado F6 Matagorda swing bridge 95° 53’ 23.75”
| River
F7
USACE boat house

| GIWw

Staff on timber bulkhead |
| Colorado |
1 River

! Colorado
River

Entrance
} Channel
| Colorado
} River

| Entrance
Channel
Colorado
River

| Entrance
| Channel

west of swing bridge in 95° 57’ 56.6”

Staff on timber pile on east
shore of channel

28° 35’ 41”
Mouth of Colorado River * 95° 59’ 05”
- west bank

Staff on day marker 3

N
reamed 1,000 ft east of highway
| GIWW - Colorado River locks; 28° 41’ 13.3” ara
28° 36’ 02.08” N
1500 ft inland from 95° 58’ 43.41”
mouth of Colorado River

Staff on timber pile at boat
dock

28° 40 14.71" Nr
River Bend Boat Camp 95° 57’ 55.57

Appendix B Locations of Galveston District Tide Staffs, September 1996

(Sheet 5 of 8) |

| Table B1 (Continued)
M MLT Ft
Waterway eae Location Lat/Long Below
2 NGVD
| Chart F (Includes NOAA Charts 11316, 11317, and 11319) (Continued)

| Giww 28° 40’ 58.1” 1.43 | Staffonsteel/timber —
West side of the east re 2
| cobra en | Colorado River lock 95° 58’ 27.5 barge fender

GIWW 28° 40’ 37.64” Staff on board pounded
| Galomdo West side of the west 95° 59’ 02.84” into channel bottom

I i: Colorado River lock approx. 5 ft from south
| River bank

28° 39 31.40" Staff on board pounded
| 3,000 ft west of mile 96° 02’ 22.46” into channel bottom
SY Pus marker 445 approx. 20 ft from south
! bank
Ship Terminals 96° 08” 02.8” north bank
Coast Guard day marker 28° 36’ 38.85” Staff approx. 40 ft from
GIWW - 28° 34’ 54.37” Just south of Oyster Lake
| able |
| Bay
rebel = Possibly another staff Mes eae pisiediaaning |
Bay west of F16
=e Turing basin 96° 11’ 16.46” dock |
River l
| Colorado el (Staff not visited during |
turning basin survey)
Channel to Staff at boat ramp under 28° 50’ ae Staff on timber bulkhead |
Red Bluff Hwy 616 bridge 96° 34’ 37.00” |
| Port Lavaca Lighthouse beach and 28° 38’ 23.17” Staff on timber bulkhead |
| Channel bird sanctuary park near 96° 36’ 44.11” near boat ramp
Hwy 35
H l Port Lavaca Port Lavaca Harbor at 28° 37’ 20.85” N/A Staff on timber pile at
Channel Lynn Bayou 96° 37’ 24.35” concrete shrimp boat dock
Poriitnunes Channel harbor of 28° 35’ 46.43” N/A Staff on timber bulkhead at
Channel F22 | refuge at Town of Port 96° 37’ 05.09” Farm Land ship dock
! Lavaca
Ship Channel beacon 71 96° 34’ 3.23”
| Ship Channel Comfort 96° 33’ 48.29” green beacon 79

| Matagorda lavees Ba 28° 35’ 39.31” Staff on damaged survey
| Ship Channel y 96° 33’ 54.70” table at beacon 65 |

Chart G (Includes NOAA Charts 11313 and 1131 —

[ Red day marker 14 96° 39’ 40.03” Victoria Barge Canal
junction
28° 13’ 37.5” Aransas wildlife refuge
| iw Aransas Refuge 96° 47’ 42.4” across waterway from the
state ramp
Survey table at 28° 11’ 02.3” At Stn 802+532.8 near
Sundown Bay 96° 51’ 01.1” green day marker 7

(Sheet 6 of 8) |

tI

Appendix B Locations of Galveston District Tide Staffs, September 1996

B7

| Table B1 (Continued)

x MLT Ft i)
Waterway may Location Lat/Long Below Comments
wv NGVD ;
Chart G (Includes NOAA Charts 11313 and 11315) (Continued)
rae To Goose Island State Park ae oe oe Seed ee a
A | Aransas Bay _| Fulton Harbor public 28° 03’ 37.4” N/A Staff near end of damaged
ransas | Aransas Bay _| boat ramp 97° 01' 59.5” timber shrimp boat pier

Rac nontoronineer 28° 01’ 27.3” N/A Staff in SW side of harbor

GIWW =o 97° 03’ 00.9” on timber bulkhead along
boat ramp

| Channel to 28° 19’ 39.56” N/A Near Victoria “Y” channel
Channel to GB Intersection with 28° 23’ 05.53” N/A Staff mounted on survey
Victoria Channel to Seadrift . 96° 43’ 40.63” table
Channel to At Bloomington railroad Staff on fender wall
Victoria bridge
GIWw At Union Carbide Plant's Staff on timber pushboat

barge canal dock
Channel to ; : 28° 24’ 28.0” N/A Staff on wooden bulkhead
GIWw Shoalwater Bay at 28° 21’ 50.6” N/A Staff on red day marker 8

Charlie’s Bait Camp 96° 34’ 51.6”

28° 20’ 37.80” N/A Staff on red day marker 10 |

28° 19’ 45.82” N/A Staff on red day marker 12
Chart H (Includes NOAA Charts 11307 and 11308)

| 27° 48) 55.4" N/A | South of Ingleside, staff
pomw | Ht Mooring) basin ngieside 97° 12’ 12.8” is ee concrete mooring platform
Staff on USACE survey 27° 23’ 05.1” N/A South of Bird Island launch
GIWW - Upper a a
| GIWW - Upper USACE survey table at 27° 29' 01.04” North of Bird Island launch
Laguna Madre Stn 78+000 97° 19’ 12.08”
GIWW - Upper - 27° 38’ 05.60” Staff on cluster of timber
Laguna Madre | Ha | JNCauseway 97° 14’ 22.24” c= piles near ship fender
Aransas Pass ; 27° 50’ 25.96” Staff on timber pile on pier
| Entrance pen eres Hee 97° 03’ 51.46” (in boat slip)
| Channel
| GIWW - North end of Dale Miller 27° 53’ 47.5” Staff on timber pile cluster
| Aransas Pass Bridge 97° 08’ 02.9” under bridge
aie 27° 48' 37.5” Staff (missing at time of
Corp pochried H7 USACE office 97° 23’ 39.8” survey) on concrete
Ship Channel
bulkhead
wn 27° 48’ 43.8” Staff on concrete bulkhead
| cor Bo Cas Harbor Bridge 97° 23’ 47.1” overlooking harbor on
Ship Channel F
south side of channel
La Quinta : 27° 50’ 16.7” Platform marks pipeline
| Jewell Fulton H10 North Shore docks in 27° 50’ 57.0” Staff on bulkhead in boat
Channel Ingleside 97° 13” 18.5” slip
| La Quinta H14 State boat ramp at 27° 50’ 15.6” Staff on timber pier
Channel Ingleside Cove 97° 13’ 13.8” adjacent to ramp
Corpus Christi H12 Turning basin at Tule 27° 49’ 09.1” Staff on steel fender
| Ship Channel bridge 97° 27’ 07.3”

(Sheet 7 of 8)

Appendix B Locations of Galveston District Tide Staffs, September 1996

[Table B1 (Concluded) |

a MLT Ft |
| K p Location Lat/Long Below !
cy NGVD faa Keer
Chart | (Includes NOAA Chart 11304)
| Port Mansfield Piling - Nav District 26° 33’ 25.01” N/A Piling in front of Navigation |
| Channel Warehouse 97° 25’ 38.63” District Warehouse |
| Port Mansfield Beacon #27 at GIWW ™* 26° 34’ N/A Beacon 27 shown on chart,
| Channel and channel junction 97° 24 not on 020 table
| [Port Mansfield ** 26° 34 Just to East of Poil bank
Port Mansfield ™ 26° 34’ % way from Gulf through
| Port Mansfield ** 26° 34 Near Gulf and channel
remw- ie Survey table at Stn 27° 12’ 56.95”
eehaee Madre 190+863 97° 25’ 23.69”
27° 04’ 34.11” Staff on private pier on
| Giww- Upper South of Yarborough BOYD 5 ; rae
| | Laguna Madre Ev Pass at Stn 242+500 97° 26’ 32.23 ee pile; house address
Chart J (Includes NOAA Charts 11301, 11303)
| Channel to : ; 26° 11’ 56.99” N/A
Channel to 26° 18’ 18.87” N/A
Channel to 26° 17’ 04.25”
Beacon #2 pease) | soe at See ea
| Channel to 26° 19’ 36.87”
Channel to 26° 19’ 55.48”
| Channel to Beacon #19 26° 19’ 27.84” |
pieringe 97° 26’ 48.28” |
9 TEP 2 New center line range table
= at | ee ae
‘ approx. Station 19+400
Brownsville 26° 00’ 56.61”
New center line range table |
on the south side of the
channel approx. Station
64+500
Feature not shown on
chart. 020 table: At Grain
Elevator east corner facing
the channel
End of turning basin west
docks, south corner just

north of navigation district
boat ramp

25° 58’ 28.30”
97° 19’ 56.93”

Brownsville
Channel

Center range table N/A

25° 57’ 21.95”
97° 23' 08.11”

Brownsville ™ 25° 57’
Channel WESUEEE S 97° 24’ A

Brownsville

Channel N/A

Grain Elevator

(Sheet 8 of 8) |

Appendix B Locations of Galveston District Tide Staffs, September 1996

B9

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Form Approved
OMB No. 0704-0188

REPORT DOCUMENTATION PAGE

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1. AGENCY USE ONLY (Leave blank) |2. REPORT DATE 3. REPORT TYPE AND DATES COVERED
October 1997

\4. TITLE AND SUBTITLE 5. FUNDING NUMBERS H
| Needs Assessment for Water-Level Gauging Along the Texas Coast for the
U.S. Army Engineer District, Galveston

Final report

6. AUTHOR(S)
Nicholas C. Kraus, Carroll I. Thurlow, Daniel J. Heilman, Anne-Lise
Lindquist, Mark W. Earle

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION
U.S. Army Engineer Waterways Experiment Station, 3909 Halls Ferry Road,
Vicksburg, MS 39180-6199 é

Conrad Blucher Institute for Surveying and Science, Texas A&M University-Corpus
Christi, 6300 Ocean Drive, Corpus Christi, TX 78412-5599

REPORT NUMBER
Technical Report CHL-97-29

10. SPONSORING/MONITORING
AGENCY REPORT NUMBER

SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

U.S. Army Engineer District, Galveston
Jadwin Building, P.O. Box 1229
Galveston, TX 77553-1229

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

12a. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

Approved for public release; distribution is unlimited.

13. ABSTRACT (Maximum 200 words)

The U.S. Army Engineer District, Galveston, conducts navigation channel maintenance and operations along the Texas
coast from the Sabine River on the north to the Brownsville Ship Channel on the south. The Galveston District has identified
a need to have both real-time and recorded water-level data in order to conduct navigation channel maintenance and
operation, coastal engineering, and environmental regulatory functions in an economical and accurate way. This report
identifies general and specific needs for water-level information, and gives recommendations for obtaining such information.
Communications alternatives for supplying real-time, voice-reported, and archived data to the Galveston District are

discussed.
14. SUBJECT TERMS 15. NUMBER OF PAGES
Navigation channel maintenance U.S. Army Engineer District, Galveston 79
Tide gauges Water level 16. PRICE CODE
Tides

SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT
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