The U.S. Geological Survey Surface Water Flow and Transpon Model in Two-
Dimensions ... two-dimensional hydrodynamic model based on the finite element
method. ...... the salinity fell within the range of 40 to 60 parts per thousand (ppt).
COMPARISON OF FINITE DIFFERENCE AND FINITE ELEMENT HYDRODYNAMIC MODELS APPLIED TO THE LAGUNA MADRE ESTUARY, TEXAS
A Thesis by
KARL EDWARD MCARTIIUR
Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE
December 1996
Major Subject: Civil Engineering
COMPARISON OF FINITE DIFFERENCE AND FINITE ELEMENT HYDRODYNAMIC MODELS APPLIED TO THE LAGUNA MADRE ESTUARY, TEXAS
A Thesis
by KARL EDWARD MCARTHUR
Submitted to the Office of Graduate SOldies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE
December 1996
Major Subject: Civil Engineering
COMPARISON OF FINITE DIFFERENCE AND FINITE ELEMENT HYDRODYNAMIC MODELS APPLIED TO THE LAGUNA MADRE ESTUARY, TEXAS
A Thesis
by KARL EDWARD MCARTHUR
Submitted to Texas A&M University in partial fulfillment of tbe requiremenrs for tbe degree of
MASTER OF SCIENCE
Approved as to style and conlent by:
Ralph A Wurbs
Wayne R. Jordan
(Chair of Committee)
(Member)
Juan 8. Val~s (Member)
Inpcio Rodriguez-lturbe (Head of Depanment)
December 1996 Major Subject: Civil Engineering
iii
ABSTRACT Comparison of Finite Difference and Finite Element Hydrodynamic Models Applied to the Laguna Madre Estuary, Texas. (December 1996) Karl Edward' McArthur, B.S., The University of Texas at Austin Chair of Advisory Committee: Dr. Ralph A. Wurbs
The U.S. Geological Survey Surface Water Flow and Transpon Model in Two-Dimensions (SWIFT2D) model was applied to the nonhem half of the Laguna Madre Estuary. SWIFT2D is a twodimensional hydrodynamic and transpon model for well-mixed estuaries, coastal embayments, harbors, lakes, rivers, and inland waterways. The model numerically solves finite difference forms of the vertically integrated equations of mass and momentwn conservation in conjunction with transpon equations for heat, salt, and constituent fluxes. The fInite difference scheme in SWIFT2D is based on a spatial discretization of the water body as a grid of equal sized, square cells. The model includes the effects of wetting and drying, wind. inflows and return flows. flow barriers, and hydraulic strucwres. The results of the SWIFT2D model were compared to results from an application of the TxBLEND model by Texas Water Development Board to the same pan of the estuary. TxBLEND is a two-dimensional hydrodynamic model based on the finite element method. The model employs triangular elements with linear basis functions and solves the generalized wave continuity formulation of the shallow water equations. TxBLEND is an expanded version of the BLEND model
to
additional
features that include the coupling of the density and momentum equations, the inclusion of evaporation and direct precipitation. and the addition tributary inflows. The TxBLEND model simulations discussed in this study were performed by personnel at the TWDB. The two models were calibrated to a June 1991 data set from a TWDS intensive inflow survey of the Laguna Madre. Velocity and water quality data were available for the three days of the survey. Tide data for a much longer period were available from TCDDN 'network stations. Results of the two models were compared at seven tide stations. eight velocity stations, and eleven flow cross sections. Sirnulated water surface elevations. velocities. and circulation patterns were comparable between models. The models were also compared on the basis of the ease of application and the computational efficiencies of the two models. The results indicate that. in the case of the Laguna Madre Estuary, TxBLEND is the more efficient of the two models.
iv
ACKNOWLEDGEMENTS
I would like to express my sincerest appreciation to Dr. Ralpb Wurbs, whose patience, understanding, and guidance were essential to the completion of this thesis. I would also like to thank the other members of my committee, Dr. Juan Val~ and Dr. Wayne Iordan. The funds for this study were provided by the Texas Wa~r Development Board in cooperation with the U.S. Geological Survey. I would like to express my sincerest appreciation to Dr. Ruben Solis and Dr. Junji Matsumoto of the Water Development Board, whose guidance and input were invaluable to the completion of this thesis. I would also like to thank the U.S. Geological Survey and Texas Disuict USGS personnel who made this project possible. In particular, I would like to thank Mr. Marsball Iennings, who has been a mentor to me during my four years as an undergradlWC and gradlWC co-op student with the USGS. His help and guidance have been greatly appreciated. I would also like to thank Mr. Ray Schaffranek and Mr. Bob Baltzer for their assistance in the early stages of this project. I would like to thank my parents, Mr. and Mrs. Roland McArthur, for their love, support, and encouragement. I especially appreciate the patience of my wife to be, Flora, who has worked at a full time engineering job, planned our wedding without my help, and put up with my long hours of work on this project. Without ber support, understanding. and encouragement, this thesis would never have been
completed.
v
TABLE OF CONTENTS
Page ABS1RAcr
..........................................................................................................................
iii
ACKNOWLEDGEMENTS .......................................................................................................... .
iv
TABLE OF CONTENTS ............................................................................................................. .
v
LIST OF FIGURES ..................................................•.....••....................•...............•........................
vii
LIST OF TABLES ....................................................................................................................... .
x
IN1RODUcnON..............................................................................................................
1
II
ill
IV
Background................................................................................................................
1
Estuary Modeling....................................................................................................... Research Objectives ...................................................................................................
3 4
LITERATURE REVIEW .................................................................................................. .
5
The Uiguna Madre Estuary .................................................•......................................
5 6
General Hydrodynamic Modeling............................................................................... Previous Studies in the Laguna Madre .......................................................................
9
TxBLEND and SW1FT2D..........................................................................................
10
DESCRIPTION OF MODELS ...........................................................................................
12
SWIFT2D ............................................................................•••.....•............................. TxBLEND ...........................................................................•..•...•..............................
12 22
PROCEDURE.................................................................................................................... Data ..........................................................................................................................
30 30
Balbymetry Generation ..............................................................................................
34 37
Grid Cell Size Selection .............................................................................................
V
VI
Simulation ................................................................................................................. Calibration................................................................................................................. Verification................................................................................................................
42
RESULTS OF SWIFI'2D SIMULATIONS.........................................................................
46
43 45
Results .......................................................................................................................
46
Sensitivity Analysis....................................................................................................
58
CO~ARISON WITH TxBLEND RESULTS....................................................................
76
TxBLEND Model Application ...................................................•............................... Comparison of Models ............................................................................................... Comparison of Results ...............................................................................................
77
76 81
vi
TABLE 'OF CONTENTS .- continued
Page
vn
SUMMARY AND CONa..USIONS ............................................ _................................ 104 S wnmary ...••.•.. ..........•.... .........•.... ............................................................................• 104
Conclusions ...............................................................•........•_............................... 105 Recommendations for Future SlUdy ............................................................................ 107 REFERENCES
......................................................................................_................................. 108
APPENDIX A
112
APPENDIXB
143
APPENDIXC
152
VITA
.......................................................................................................................... 175
vii
LIST OF FIGURES FIGURE
Page
1
Location Map of the Laguna Madre Eswary ....................................................•.................•
2
2
Locauon of Variables on the Model Grid ........................................................................... .
18
3
Simple SWIFT2D Computational Grid with Arbitrary Openings ....................................... .
20
4
Example of a Regular, Square Finite Difference Grid .........................................................
25
5
Example of a Linear, Triangular Finite Element Mesh ...................................................... .
25
6
Upper Laguna Madre Study Area Simulated with SWIFT2D and TxBLEND .................... .
31
7
Distribution of Wind Directions Observed at the Corpus Christi NAS Wind Station .......... .
33
8
Distribution of Wind Speeds Observed at the Corpus Christi NAS Wind Station ............... .
34
9
Upper Laguna Madre 400 Meter Grid (148x213 cells) ....................................................... .
39
10
Upper Laguna Madre 200 Meter Grid (296x426 cells) ........................................................
40
11
Typical S'WIFr2D Grid Section Which Shows the Stair-step Effect in the Representation of Channels with a Regular, Square Grid................................................... .
41
Locations of Tide Stations at Which Simulated and Observed WarD: Levels Were Compared ................................................................................................................ .
47
Locations of Velocity Stations at Which Simu.laled and Observed Velocities Were Compared .............................................................................................................. '"
48
14
Locations of Cross Sections at which Simulated Flows Were Compared ............................ .
49
15
Calibrated Water Levels at the Corpus Christi Naval Air Station Tide Station ....................
51
16
Calibrated Water Levels at the Packery Channel Tide Station............................................ .
51
17
Calibrated Water Levels at the Pita Island Tide S tation ..................................................... .
SI
18
Calibrated Water Levels at the South Bird Island Tide Station ...........................................
52
19
Calibrated Water Levels at the Yarborough Pass Tide Station ........................................... .
52
20
Calibrated Water Levels at the Riviera Beach Tide Station ............................................... ..
52
21
Calibrated Water Levels at the E1 Toro Island Tide Station ................................................
S3
22
Calibrated Velocity at the Humble Channel Station ............................................................
55
23
Calibrated Velocity at the GIWW at JFK Causeway Station...•...........•.......•..............•.........
55
24
Calibrated Velocity at the GIWW Marker 199 Station ............••....•..........••...........•.............
S5
25
Calibrated Velocity at the North of Baffin Bay Station .................•..•..............•..............•..•..
56
26
Calibrated Velocity at the Mouth of Baffin Bay Station ......•..•......•.••..........•.••...............•....
S6
27
Calibrated Velocity at the South of Baffin Bay - Middle Station .........................................
56
28
. Calibrated Velocity at the South of Baffm Bay - West Station.............................................
57
29
Calibrated Velocity at the North Land Cut Station..............................................................
S7
30
Differences in Water Levels Due to the Time Step, Pita Island ...........................................
63
12 13
viii
LIST OF FIGURES - continued
FIGURE
Page
31
Differences in Water Levels Due to the Time Step, Riviera Beach ..................................... .
63
32
Differences in Velocity Due [Q the Time Step, GIWW at JFK Causeway ............................ .
63
33
Differences in Velocity Due [Q the Time Step, South of Baffin Bay-Middle ....................... .
64
34
Differences in Flow Due to the Time Step, GIWW at JFK Causeway..................................
64
3S
Differences in Flow Due to the Time Step, Baff'm Bay........................................................
64
36
Differences in Waler Levels Due to the Wind Stress, Pita Island ........................................
67
37
Differences in Water Levels Due to the Wind Stress, Riviera Beach ...................................
67
38
Differences in Velocity Due to the Wind Stress, GIWW at JFK Causeway..........................
67
39
Differences in Velocity Due to the Wind Stress, South of Baffin Bay-Middle......................
68
40
Differences in Flow Due to the Wind Stress, GIWW at JFK Causeway ... _..........................
68
41
Differences in Flow Due to the Wind Stress, Baffin Bay.....................................................
68
42
Differences in Water Levels Due to Manning's n, Pita Island.............................................
71
43
Differences in Water Levels Due to Manning's n, Riviera Beach ......._................................
71
44
Differences in Velocity Due to Manning's n, GIWW at JFK Causeway..............................
71
4S
Differences in Velocity Due to Manning's n, South of Baffin Bay-Middle ..........................
72
46
Differences in Flow Due to Manning's n, GIWW at JFK Causeway....................................
72
47
Differences in Flow Due to Manning's n, Baffin Bay...................... _..................................
72
48
Differences in Velocity Due to Viscosity, GIWW at JFK Causeway ....................................
73
49
Differences in Flow Due to Viscosity, GIWW at JFK Causeway.........................................
73
50
Differences in Flow Due to the Advection Option, LM at North Land Cut..........................
74
51
TxBLEND Finite Element Mesh for the UpPer Laguna Madre Esruary, Corpus Christi Bay, and Copano Bay System .....................................................................
79
52
Close-up of the TxBLEND Mesh in the Vicinity of the JFK Causeway ...............................
80
53
Comparison of Waier Levels at the Corpus Christi Naval Air Statioll Tide Station .............
82
54
Comparison of Water Levels at the Packery Channel Tide Station. __ ..............................
82
55
Comparison of Water Levels at the Pita Island Tide Station ...............................................
82
56
Comparison of Water Levels at the South Bird Island Tide Station __.................................
83
57
Comparison of Water Levels at the Yarborough Pass Tide Station ..._.................................
83
58
Comparison of Water Levels at the Riviera Beach Tide Station ........._...............................
83
59
Comparison of Water Levels at the El Toro Island Tide Station......_.................................
84
60
Comparison of Velocity at the Humble Channel Station .................._.................................
86
ix
LIST OF FlGURES - continued
FIGURE
Page
61
Comparison of Velocity at the GrNW at JFK Causeway Statioo ........................................ .
86
62
Comparison of Velocity at the GrNW Marker 199 Station ................................................ .
86
63
Comparison of Velocity at the North of Baffin Bay Statioo.................................................
87
64
Comparison of Velocity at the Mouth of Baffin Bay Station................................................
87
65
Comparison of Velocity at the South of Baffin Bay· Middle Station...................................
87
66
Comparison of Velocity at the South of Baffin Bay • West Station .•....................................
88
67
Comparison of Velocity at the North Land Cut Station.......................................................
88
68
Comparison of Flow at the GIWW at Corpus Christi Cross Section....................................
89
69
Comparison of Flow at the Corpus Christi NAS Cross Section ...........................................
89
70
Comparison of Flow at the Packery Channel Cross Section ................................................
89
71
Comparison of Flow at the Humble Channel Cross Section ................................................
90
72
Comparison of Flow at the GIWW at JFK Causeway Cross Section....................................
90
73
Comparison of Flow at the Laguna Madre at Pita Island Cross Section...............................
90
74
Comparison of Flow at the Laguna Madre at South Bird Island Cross Section....................
91
75
Comparison of Flow at the Laguna Madre at Green Hill Cross Section...............................
91
76
Comparison of Flow at the Mouth of Baffin Bay Cross Section...........................................
91
77
Comparison of Flow at the Laguna Madre at Yarborough Pass Cross Section .....................
92
78
Comparison of Flow at the Laguna Madre at North Land Cut Cross Section.......................
92
79
TxBLEND Simulated Velocity Vectors, June 10, 09:00......................................................
95
80
SWIFT2D Simulated Velocity Vectors, JWlC 10, 09:00.......................................................
96
81
SWIFI'2D Simulated Velocity Vectors near the John F. Kennedy Causeway, June 10, 09:00 ..................................................................................................
97
82
TxBLEND Simulated VelOCity Vectors. June 10. 18:00......................................................
98
83
SWIFT2D Simulated Velocity Vectors. June 10. 18:00.......................................................
99
84
SWIFI'2D Simulated Velocity Vectors near the John F. Kennedy Causeway. June 10. 18:00 .................................................................................................. 100
85
TxBLEND Simulated Velocity Vectors. June 11. 00:00 ............... _..................................... 101
86
SWIFI'2D Simulated Velocity Vectors. June II, 00:00 ....................... _............ ······........ ·... 102
87
SWIFI'2D Simulated Velocity Vectors near the John F. Kennedy Causeway. June 11. 00:00 .................................................................................................. 103
x
LIST OF TABLES
TABLE
Page
1
Description of the Integration Correction Schemes Available in SWIFr2D .......................•
19
2
Data Observation Stations Used in the Study of the Upper Laguna Madre Estuary ....•......••
32
3
Nautical Charts Used in the Development of the Bathymetry Data for the Laguna Madre Estuary .........................•.........................................•.••.....•••.......•••.•••.....•.•.•
35
4
Root Mean Squared Errors between Simulated and Observed Water Levels........................
53
5
Root Mean Squared Errors between Simulated and Observed Velocities.............................
54
6
SWIFT2D Model Parameters Varied for the Sensitivity Analysis .......................................
59
7
Courant Nwnbers Associated with the Time Steps Used in SWIFr2D for the Sensitivity Analysis............................................................................................................
61
Root Mean Squared Errors between Simulated and Observed W~ Levels for Simulations with Different Time Steps ........................................•.•••.•........:.......................
61
Root Mean Squared Errors between Simu.laled and Observed Velocities for Simulations with Different Time Steps...............................................................................
62
Root Mean Squared Errors between Simu.laled and Observed W~ Levels for Simulations with Different Wind Stress Coefficients ................•.....•.....•...•.........................
65
Root Mean Squared Errors between Simu.laled and Observed Velocities for Simulations with Different Wind Stress Coefficients ..............................•...........................
66
Root Mean Squared Errors between Simulated and Observed Water Levels for Simulations with Different Manning's Roughness Coefficients ..........................................
69
Root Mean Squared Errors between Simu.laled and Observed Velocities for Simulations with Different Manning's Roughness Coefficients ...............................•..........
70
Sununary of the Wetting and Drying of Grid Cells during the 15 Day Sensitivity Analysis Simulations..........................................................................................................
75
Geometric Characteristics of the SWIFT2D Finite Difference Grid aDd the TxBLEND Finite Element Mesh ........................................................................................
77
Root Mean Squared ErrorS between SWIFr2D and TxBLEND Simulated Water Levels and Observed Water Levels ..•...................•.............• _...................................
84
Root Mean Squared Errors between SWIFr2D and TxBLEND Simulated Velocities and Observed Velocities.....................................................................................
85
Root Mean Squared Errors between SWIFr2D and TxBLEND Simulated Flows................
93
8 9 10 11 12 13 14 15 16 17 18
1
I INTRODUCTION
BACKGROUND
The need for freshwater inflows to maintain the ecological stability of bays and estuaries has provided the impews for a wide range of swdies along the Texas Coast. Texas Senate Bill 137 passed in 1975 mandated comprehensive studies of freshwater inflows
to
Texas bays and estuaries (Texas
Department of Water Resources 1983). These studies led to a series of reportS on the influence of fresh water inflows on the seven major bay and estuary systems along the Texas coast. Similar legislation passed in 1985 mandated an update of the earlier sWdies. In an effon to help predict the impact of various schedules of freshwater inflows. the Texas Water Development Board began a series of investigations and hydrodynamic modeling studies of Texas bays andeslWlries (Longley 1994). The Laguna Madre estuary is one of only three oceanic. hypersaline. lagoonal areas in the world. The system is composed primarily of shallow tidal flats that extend from Corpus Christi to Brownsville. The estuary is divided into two parts by a wide land bridge south of Baffin Bay. The Gulf Intracoastal Waterway (Grww) is the only connection between the upper and lower portions of the estuary. The Laguna Madre estuary supportS a significant portion of the commercial fishing industry in Texas (Laguna Madre. 1983) and is cenaai to the economy of a large section of the Texas coast. Construction of the GrvYW in the late forties significantly changed the patterns of flow in the Estuary. The Grww created a continuous conduit for flow that extended the entire length of the estuary. The dredging required to maintain the channel has resulted in a chain of spoil islands that are intermittently spaced along the length of the estuary parallel to the GIWW. The spoil islands have also had an influence on circulation patterns in the estuary. The Location of the Laguna Madre is shown in Fig. l. The unique nature of the Laguna Madre Estuary presents a number of problems that make the system difficult to model. The presence of large tidal flats requires a hydrodynamic model that is able to simulate the flooding and drying of model computational cells. The lDlusual characteristics of the estuary system prompted the Texas Water Development Board (TWDB) to evaluate alternatives to the TxBLEND two-dimensional. finite element model which they have applied to several systems along the Texas Gulf Coast.
The journal model is the ASCE JOUTTllJi of Hydraulic Engineering.
2
~--
--~.
;"
\,
-
/
.,-
/,-\.o·i.~'·
.S'
SANPAlrIlClO
, ~~
....' -
'"
.--.
~
,.. ..
'.
/
. ,,,
EXPLANATION
!
~\~
Tide Gage
NUEceS III
Wind Station
*
Velocity Station
- - Estuary Boundary ......... County Boundary
KLSBERG
-
Ship Channels
KENEDY
o o
.~,-.-~
\_
..
_._-
CAMERON
""",
... " i;\ ~.
FIG. 1. Locatio. Map orthe Laguna Madre Estuary
so MILES
21
21
so KlLOME1eW
3
The U. S. Geological Survey (USGS), under contract with the TWDB, has tested the applicability of the USGS Surface-Water, Integrated, Flow and Transpon hydrodynamic model (SWIFI'2D) to the Laguna Madre System. The SWIFI'2D model is a two-dimensional, vertically integrated, fInite difference model with the capability to simulate both flow and constituent transpon. The results of the SWIFI'2D modeling effon are compared to the available results from the modeling effons of the TWDB. The TxBLEND model has not yet been applied to the lower portion of the Laguna Madre south of the land cut. This study will focus on the ability of the models to simulate the upper portion of the Laguna Madre north of the land cut. The SWIFT2D model, calibrated for hydrodynamics, allows for a comparison of the ability of the two models to handle a number of imponant forcing functions. The effects of wind on the behavior of the model are especially interesting in the case of the Laguna Madre Estuary. The model will also allow an evaluation of the effects of wetting and drying on the extensive tidal flats in the estuary. One of the major goals of the study is to consider the ability of the simple, regular, square grid fmite difference representation of the estuary required for SWIFI'2D to match the more geometrically accurate linear ttiangular fmite element representation required for the TxBLEND model. The requirement in SWIFI'2D for regular grid cell sizes is somewhat of a liability in the case of the Laguna Madre. The large area and the unusual flow characteristics of the estuary requires a fairly small cell size. The Gulf Intercoastal Water Way (GIWW), which for most of its length has a width of approximately 38 meters (125 feet) and a project depth of 3.7 meters (12 feet), transmits a large pan of the flow in the estuary. In order to accurately represent the true bathymetty of the chartnel, a cell size on the order of the width of the GIWW would be required. Such a grid size would require approximately 3.15 million cells in order to represent upper portion of the Laguna Madre Estuary. The ttianguiar fInite element representation used by TxBLEND allows for variation of cell sizes. The cells can be very small in the vicinity of the GIWW or other imponant features, while cells in the wide, shallow flats can be significantly larger. However, elements which are
toO
large can cause
nwnerical instabilities in the TxBLEND model as discussed by Solis (1991). The limitations on cell size and computer power necessitated separation of the Laguna Madre into two pans for the SWIFT2D modeling.
ESTUARY MODELING The primary concerns in estuary modeling are the simulation of flow patterns and salinity distributions. Both of these factors are of vital concern to the health and productivity of bay and
4
estuary systems. The effects of fresh water inflows to bays and estuaries has been studied extensively in the state of Texas. State law mandates that the necessary fresh water inflows to such systems be insured. Hydrodynamic simulation models are often used to determine the relationship between fresh water inflows, circulation patterns, and salinity. Results from hydrodynamic simulations are used in conjunction with planning level optimization models to operate systems of reservoirs upstream of the estuaries to insure the health of the eswary. There exists a wide range of estuary hydrodynamic models in the literature. Both finite difference and finite element models have been used extensively, and the models have increased in complexity as computer resources have improved. Finite difference solution schemes were more successful in early hydrodynamic models, however, the inttoduction of the wave continuity equation formulation has led to the creation of many robust finite element schemes (Wesr.erink, 1991). Both finite difference and finite element techniques have been used in a wide variety of two and three· dimensional hydrodynamic models. The advent of more powerful computer resources has spurred the growth in the nwnber of three-dimensional models.
RESEARCH OBJECTIVES
The primary goal of the swdy is to evaluate the SWIFT2D model as an alternative to the TxBLEND model used by the Texas WaJer Development Board. Consideration will be given to the ease of application of the model as well as the quality and usefulness of the model results. The specific objectives of the swdy are:
l. Calibrate and verify the SWIFI'2D model for the upper and lower Laguna Madre Estuary with data
from the Texas Water Development Board. Texas Coastal Ocean Observation Network, National Oceanic and Atmospheric Administration, and any other available data sources; 2. Compare the quality of the model result and the efficiency of the model application with that of the TWDB 's TxBLEND finite element model Results are compared through evaluations of root mean squared errors between simulated and observed values and through visual inspection of plots of simu1atcd and observed values. The results of the study will be discussed in the thesis and also will be delivered to the TWDB.
5
II LITERATURE REVIEW
THE LAGUNA MADRE ESTUARY
The Laguna Madre Estuary syslem presents special problems in any effort to apply a hydrodynamic model. The estuary is one of only three oceanic. lagoonal. hypersaline areas in the world. Most of the Laguna Madre is composed of shallow flats. which eXlend the length of the estuary from Corpus Christi to Port Isabel. The upper and lower Laguna Madre is separaled by a wide sand flat below Port Mansfield, Texas. The total surface area of the estuary at mean waler level is approximalely 1658 square kilometers (640 square miles). while the area at mean low waler the surface area is approximalely 1137 square kilometers (439 square miles). As the difference in surface area between mean waier level and mean low waler indicates. there are large areas of shallow tidal flats that tend to flood dry periodically. The Gulf Intracoastal Walerway (Grww). which runs the entire length of the estuary at an average project depth of approximalely 12 feet, is the only connection between the two halves of the Laguna Madre. The Laguna Madre has only five connections with the ocean and adjacent walers. At the north end. the estuary opens onto Corpus Christi Bay at the Humble Channel. Gulf Intracoastal Waterway. and Packery Channel. The southern half of the estuary opens onto the Gulf of Mexico at the Port Mansfield and Port Isabel ship channels. A limiled amount of freshwaler inflow to the estuary enlers primarily from Baffm Bay in the upper Laguna and the Arroyo Colorado in the lower Laguna. Circulation in the estuary is primarily wind driven. and the tidal range is generally on the order of half a foot or less (Texas Department ofWaler Resources 1983). In a report mandaled by Senale Bill 137 passed in 1975. the Texas Department ofWaier resources (1983) discusses in detail the characleristics of the Laguna Madre Estuary. The discussion ranges from the hydrology. circulation. and salinity to the nutrient processes and productivity of the estuary. The report on freshwaler inflows to Texas bays and Estuaries ediled by Longley (1994) was the result of similar legislation passed in 1985. Kjerfve (1987) presents a summary of the characleristics of the Laguna Madre that is drawn from a number of sources. The Laguna Madre is the southernmost of the eswaries along the Texas coast. The regional climale of the coastal zone of south Texas is lisled as tropical semiarid and is anomalous enough to be considered a "problem clirnate." The average precipitation raIe in the region approximalelyequals the raIe of evaporation. Additionally. there is liale freshwaler inflow into the north~rn Laguna Madre. Inflows from Baffm Bay average approximalely one cubic meier per second
and may cease altogether during periods of little precipitation (Kjerfve 1987). Direct precipitation accounts for an average of 65% of the freshwaler inflow to the Laguna Madre (Texas Department of
6
Water Resources 1983). Kjerfve also discusses the hypersaline nature of the estuary. Before completion of the GIWW. the nonhem half of the estuary was thought to be in good condition when the salinity fell within the range of 40 to 60 parts per thousand (ppt). The salinity was observed to approach 100 ppt during periods of unusually low rainfall. Construction of the GIWW improved the exchange of water between Corpus Christi Bay and the upper Laguna Madre. however the estuary remains hypersaline. The salinity is highest at locations beyond the reach of tidal and low·frequency exchanges. The mean salinity at the nonhem end of the estuary was 31.5 ppt The salinity increased southward at a rate of approximately 0.18 ppt/km (Kjerfve 1987). A recent article by Cartwright (1996) discusses the economic and ecological impact of the Gulf Intracoastal Waterway on the Laguna Madre Estuary. The article focuses primarily on the impact of maintenance dredging of the GIWW on the health and stability of the estuary. Studies have concluded that the maintenance dredging is destroying the sea grass beds in the estuary. Sea grass forms the base on which life in the Laguna Madre is dependent The reduction in sea grass has led 10 serious reductions in the productivity of the estuary. Cartwright (1996) states that while the connection of the upper and lower Laguna Madre as a result of the GIWW land cut increased circulation and productivity in the estuary. significant delrimental effects also were created. Barge traffic along the GIWW causes substantial erosion of sea grass habitat in the flats adjacent 10 the channel. The spoil islands created as a result of the maintenance dredging have had a significant effect on circulation pauerns in the estuary. The islands range in size from 20.000 square meterS 10 over 200.000 square meters. Cartwright (1996) also discussed the possibility of a 420 Ian extension of the GIWW inoo Mexico. The extension of the channel would dramatically increase the traffic through the Laguna Madre portion of the GIWW. Numerous additional works discuss items such as estuary productivity. ecology. and other characteristics. While informative, these works have little bearing on the simulation of hydrodynamics in the estuary and are not included in this report
GENERAL HYDRODYNAMIC MODELING A wide variety of hydrodynamic models are discussed in the literature. Both two and threedimensional models have been used extensively in applications 10 bay and estuary systems. Efficient finite difference and finite element codes are available from a number of sources. The development of these models has generally kept pace with the rapid pace of improvements in computer systems. HydrodynamiC modeling seems to have a higher priority in Europe, Asia, and Canada (Westerink and Gray 1991). Although U.S. contributions in the area of hydrodynamic modeling are a small fraction
7
of the·w{)rld total, the present discussion will be limited primarily to contributions made by U.S. model developers. Model Developments Finite difference base spatial discretizations were the most successful schemes in the early development of hydrodynamic models due to the use of staggered spatial grids (Westerink and Gray 1991). Early finite element schemes were burdened by severe spurious modes that required the heavyhanded addition of nonphysical dissipation. The introduction of the wave continuity equation by Lynch and Gray (1979) led to more robust finite element schemes. Numerical schemes based on coordinate tranSformations also were under development in the la1e 1970' s. These schemes led to finite difference codes with increased grid flexibility and boundary fitting characteristics. As a result, the features of finite difference and finite element based solutions to the shallow water equations have become much more similar (Westerink and Gray 1991). Significant progress has been made in the development of robust hydrodynamic models. however, a wide range of shortcomings remain
to be
addressed. Several issues rela1ed to depth
averaged flow computations need to be addressed. These include time stepping limitations. long term stability. conservation of integral invarients, resolution of sharp fronts, supercritical flows. wetting and drying of land boundaries. convective term treatment, and lateral momenrum transport (Westerink and Gray 1991). The size of depth integrated flow problems and the abilities of hydrodynamic models have increased along with available computer capacities. Two-dimensional Finite difference Models Most of the fmite difference models in current use apply spatially staggered discretization. The SIMSYS2D, which is the previous version of SWIFT2D is based on the staggered grid Alternating Direction Implicit (ADO solution. An alternative Turkel-Zwas scheme that attempts to overcome the severity of the Courant time step limitation is discussed by Navon and deVilliers (1987). The method discretizes the Coriolis term on a coarser mesh with a fourth order approximation. Casulli and Cheng (1990) srudied the stability and accuracy of Eulerian-Lagrangian methods which appear to take advantage of larger time steps. Efforts to improve the ability of finite difference models to accurately represent irregular geometry have led to the use of coordinate tranSformation schemes and irregular grid sizes. Extensions of these efforts to problems of flooding in tidal flats have led to models with meshes that deform to fit the shape of the changing physical domain. The ttaditional approach has been to apply fixed spatial grids and specify small threshold depths over the area subject to inundation and drying. Austria and Aldama (1990) solve the one dimensional shallow water equations using a coordinate
8
transformation which maps a defonning physical domain with moving boundaries inlO a fIxed computational domain.
Two-dimensional Finite element Models Finite element schemes have become more common than fInite difference schemes for the solution of the shallow water equations, however, some of the same ideas are being examined in both. Time discretization schemes similar to those used in f!nite difference models have been used in finite element schemes to rake advantage of the ability of the method to perfonn long tenn simulations, Frequency domain based schemes have also been used for tidal circulation or other periodic events. The frequency domain scheme has the advanwge of efficiency for long tenn simulations. no stability constraints on the time step, and the ability
10
irudy nonlinear tidal constiruent interactions in a
controlled manner (Westerink and Gray 1991 . Flooding and drying effects also ha\ been addressed in fmite element models. A.lcanbi and K.atopodes (1988) solved the primitive shallo . water equations through the implementation of a
scheme which employs moving and defonnin . fmite element mesh. The deforming mesh exactly follows the land water interface. Siden and L 1ch (1988) usc the wave continuity fonn of the shallow water equations with moving boundaries. The nethod also exactly follows the interface and uses a time stepping scheme with elastic mapping of
~terior
nodes.
The TABS system developed by the l 5. Anny Corps of Engineers Wawways Experiment Station hydraulic group has been used in a nur. .lCr of applications. The TABS system is comprised of the Geometry File Generation program (GFGE
'D, RMA2, RMA4, and SED2D. The GFGEN software
provides an extensive system for the developrr nt of the fmite element meshes required by the system. Jones and Richards (1992) discuss an early ve .ion of the GFGEN software, which in an earlier from was called FastTABS. RMA2 is a oneltwo-dir :ensional, vertically·averaged, fully-implicit f!nite element model. The model can usc both one:; ld two-dimensional elements. The two-dimensional elements may be either triangular or Il1Ipezoi~
~
~
is....
w
:>
-'~4OO'=---:'-:::200=----;;27:4oo=---~,2OO=~--2::-4OO-f=---:':-:2=00-::----;2:-:4OO=---7,2:::oo=---2::-4:'::oo:::---,:-:2=oo-::----' '0
"
'2 June
,99'
'3
'4
FIG. 23. calibrated Velocity at the GIWW at JFK causeway Station
'.0 SWIFT2D
c
z
0 () w
"'"'"""'"'">'"
Observed
0.5
0
~
~
~ -0.5 1:5 .....
'"
:>
-'~4OO·1:-:----:0-:.800::::---':-:600=---:24:l:oo::::---:0800::::::-::---;'-=.600;;;;---2::-4OO;I;;;;--;;0800:;:;;;;--';-;600;---;;2400;;:;;---;0;;;800;---;,0: ;;;;---' 600 ,3 '2 '0
"
June
,99'
FIG. 24. calibrated Velocity at the GIWW Marker 199 Station
56
1.0' 0
SWIFT2D
u
Observed
~
"" (J)
a: w
0.. (J)
-...3 a:
0.5
J
~
...>-
8
·0.5
...J W
>
.1g 4OO
0800
1600
2400
0800
10
1600
2400
0800
11
1600
2400
0800
12
1600 13
June 1991
FIG. 25. Calibrated Velocity at the North of Baffin Bay Station
,
10 0
z u w
SWIFT2D
0
(J)
a:
Observed 0.5 -
-
u.J
"(J)
a:
...ww
---- ....
0
'"'
::Ii ~
""
I
.1.g 4OO
0800
1600 10
2400
1600
0800
2400
11
1600
0800
2400
12
1600
0800 13
June 1991
FIG. 26. calibrated Velocity at the Mouth of Baffin Bay Station
1.0 SWIFT2D
0 Z
0
Observed
U
~ 0.5
a: w
0.. (J)
a:
...ww
0
-.... __ ...
... _..
::Ii
~
~ ·0.5
8 ~
w
>
.1g4OOL_-0.... 800,.,.....--1600":-::---:2,..J4oo",,--70800:!=--1:-;'600~--::-24O~0--:oaoo=:----:-1600:!=--:2:-:4OOL,;-;;---::0::':800:::--:-;:1600=--,..J 10
12
11
June 1991
FIG. 27. calibrated Velocity at the South of Baffin Bay-Middle Station
13
57
,0 r:---,.....----,--T,-----,---~--,----.--~--r_r---.-----,-____, SWIFT2D ObS8f\'ed
"
'0
'2
-
'3
June '991
FIG. 28. calibrated Velocity at the South of Baffin Bay-West Station
1.0 SWIFT2D
0
5
Observed
(.)
w
-1~400;:;;---;;0:;:;800;;;---;-;'600;;;;;---;2~400;;;--;;;0800t::;;---;,-;;60~O:---:;-:240:\::O;;---;0~800:::::--7.'800=--;2:-:1doo:::::---::0800=--'-=600=--J 10
"
12
13
June 1991
FIG. 29. Calibrated Velocity at the North Land Cut Station
The simulated velocities are generally smaller than expected, primarily due to the finite difference grid representation of the channels. The actual widths of the channels are approximately 95 and 125 meters for the GIWW at JFK Causeway and the Humble Channel. respectively. These widths are smaller than the width of a single grid cell. however. the SWIFf2D requires passes between no flow barriers to be at least two cells wide. The corresponding reduction in the amount of restriction on the flow tended to decrease the simulated velocities. The depth of the grid cells was reduced to compensate for the increased width of the passes. The resulting wider and shallower channels tended to reduce
the simulated velocities. A similar problem probably caused the disparity between simulated
and observed velocities at the GIWW at Marker 199 station. The SWIFf2D representation of the
58
GIWWis both wider and more shallow than the actual channel. The result is a substantial reduction in velocity. The observed velocities at the southern end of the estuary, in contrast, are small and appear to be largely dependent on wind. The SWlFI'2D simulated velocities match as closely as can be expected when the grid resolution and wind driven nature of the circulation are considered. The use of additional wind data from a station located in the southern pan of the upper Laguna Madre might improve the representation of velocities, however, the actual observed velocities are so small that the potential gain in accuracy may be offset by the increased data requirements.
Flow Simulated flows were output for the eleven cross sections shown in Fig. 14. These cross sections represent the primary connections with the driving tides at the Corpus Christi NAS and E1 Toro Island stations, major conduits of flow, and representative sections across the width of the estuary. Actual flows were not measured during the time period simulated by the SWIFT2D and TxBLEND models, therefore a discussion of flow is reserved for the section on the sensitivity analysis and Chapter V which compares the results from the two models. Comparisons between simulated flows are made in these sections.
SENSITIVITY ANALYSIS SWIFT2D provides a number of calibration parameters which can be adjusted to yield the best possible fit to measured data. A simple sensitivity analysis was performed to evaluate the effects of variations in the different parameters on model results. The set of five parameters shown in Table 6 were adjusted to illusttate the effect of each parameter on the model.
59
TABLE 6. SWIFr2D Model Parameters Varied for the Sensitivity Analysis. Parameter Time Step (seconds) Wind Stress Viscosity (mIls) Advection Option Manning'sn
Low Value
Calibrated Value
High Value
180
360
720
0.0001
0.0015
0.0026
0
1
10
Arakawa
Leendertse
No Advection
25% reduction
0.025-0.040
25% increase
0.030
(Distributed)
(Distributed)
(Distributed)
(Constant)
Other
The wind stress coefficient and the Manning's n value were observed 10 have the largest effect on model results. Selection of the time step also has a significant effect on the model results. The other parameters had much smaller effects on the calibration.
Time Step
The length of the time step can contribute significantly 10 inaccuracies in the computations of the model. Despite the unconditional stability of the ADI method, serious errors can arise when large time steps are used. Substantial errors have been observed in the simulation of both water levels and velocities at large time steps. Stelling et al. (1986) describe this so-called ADI effect as a fundamental property of numerical integration by a splitting method, despite the splitting technique applied and
despite the irregularity of the model boundaries. The Courant number, which serves as an upper limit on the time step for explicit models, is defmedby 112
.............................•..•.•••..•••.•.•......•.•.•.....................•.. (27)
where Cfis the Courant number, g is the acceleration of gravity, H is the cell depth, and.:U and ~y are the dimension of the cell in the;c and y directions respectively. In the case of SWIFT2D ~ equals ~y and (26) reduces 10
Cf
= 21:(2gH) .....................................................................................................................(28) 1/2
&
where 6s is the length of a side of the square grid cells. If ~ equals ~y then the Courant limitation implies a restriction on the time step of the form
60
7:
< [ 2( 2gH) 1/2]· ..............··· ...... ·· ............ ·....·...... ·................·....................................................(29)
Significant numerical errors may occur at time steps much larger than this limiting value. Analytical estimates oC the ADI effect are difficult to make, since quantitatively the effect depends on the shape of the geometry or bathymetry combined with the spatial grid size. An essential feature of an ADI method for the approximation of shallow water equations is
that for one time step the fmite difference equations are solved alternatively implicit in the x direction and implicit in the y direction in two consecutive computational steps. Due to this, a tidal signal cannot be transferred more than once through an angle of 9()0 in one complete ADI time step. Hence, in one time step a signal cannot travel more than once through two bends in e.g., a zigzagging channel, halfway around an island or tidal flat. or around a peninsula shaped projection of the coastline. For accurate representation of hydraulics, however, this may be required (Stelling et al. 1986). The larger the Courant number, the larger the analytical area of influence of a grid feature on surrounding grid cells. Since the tidal signal can not pass more than once through an angle of 9()0 in a time step, the actual area of influence will be smaller than the analytical area of influence implied by a large Courant number. The SWIFI'2D grid for the upper Laguna Madre incorporates all of the features described by Stelling et al. (1986), which lead the ADI effect The GIWW is a zigzagging narrow channel which runs the length of the estuary and provides much of the circulation. The spoil islands created by the maintenance dredging of the GIWW are also prevalent in the estuary. In addition, there exist large areas of tidalllats and several peninsulas in the model grid. The effects of these features is readily apparent in plots which compare water levels and velocities simulated at large time steps to observed values. The SWIFI'2D calibrated model of the upper Laguna Madre was run with time steps of 180, 360, and 720 seconds. Table 7Iists the time steps with the associated Courant numbers. The courant numbers were calculated with both the average and maximum depths, and the average depth oCthe GIWW in the model grid.
61
TABLE 7. Courant Numbers Associated with the Time Steps Used in SWIFT2D ror the Sensitivity Analysis
Courant Numbers Time Step in Seconds (Minutes)
A verage Grid Cell Depth
Maximum Grid Cell Depth
Average Depth of Cells in the GIWW
180 (3)
8.1
17.8
13.6
360 (6)
16.2
35.7
27.2
720 (12)
32.3
71.3
54.3
As expected, the three minute time step yielded the most accurate simulation of water levels and velocities. RMSE's and Plots of water levels at the Pita Island tide station and RMSE's and velocities at the GIWW at the JFK Causeway velocity station show a clear deterioration in the simulated time series as the time step increases. Tables 8 and 9 show the RMSE' s between observed and simulated water levels and velocities.
TABLE 8. Root Mean Squared Errors between Simulated and Observed Water Levels ror Simulations with Different Time Steps
RMSE (meters) 360 seconds (Calibrated)
180 seconds
720 seconds
Water Level Station Corpus Christi NAS
0.001
0.001
0.001
Packery Channel
0.043
0.042
0.045
Pita Island
0.036
0.036
0.038
South Bird Island
0.059
0.058
0.062
Yarborough Pass
0.067
0.066
0.069
Riviera Beach
0.124
0.124
0.126
El Taro Island
0.006
0.006
0.005
Average
0.048
0.048
0.049
62
TABLE 9. Root Mean Squared Errors between Simulated and Observed Veloc:ities (or Simulations with Different Time Steps RMSE (meters per second) 360 seconds (Calibrated)
180 seconds
720 seconds
Humble Channel
0.13
0.13
0.12
orww at the JFK Causeway orww at Marker 199
0.16
0.16
0.19
0.19
0.17
0.21
North of Baffin Bay
0.10
0.10
0.10
Mouth of Baffm Bay
0.08
0.08
0.09
South of Baffin Bay-Middle
0.11
0.11
0.11
South of Baffin Bay-West
0.08
0.07
0.07
North Land Cut
0.12
0.12
0.13
Average
0.12
0.12
0.13
Water Level Station
An evaluation of the RMSE's showed that the errors increased with increasing length of the time step
at almost every station. The largest increases in the RMSE occurred at stations located in the ONfW. The largest increase in the error between simulated and observed velocities occurred at the ONfW at Marker 199 station which is the southern most velocity station in the ONfW still affected by the tidal signal. The ADI effect is much more evident in plots of the simulated and observed times series. Figs. 30 through 35 show the effect of the time step on the simulation of water levels, velocities, and flows. There are no measured data available during the time of the simulations at the cross sections used in the model comparisons. Results with the 720 second time step show a clear lag in phase for both water levels and flows. This lag is a direct result of the ADI effect described by Stelling et al. (1986). The results at the two stations are dependent on flows through stair-stepped reaches of channels. The large time step does not allow accurate propagation of flow through multiple bends in the channel The 180 second time step produced the most accurate results, however, the 360 second time step was selected for the simulation runs discussed in this repon. The 360 second time step offered much shorter simulation times with minima110sses in accuracy. Run times for a 15 day simulation with a three minute time step were on the order of 4.25 hours while run times for the 6 and 12 minute time steps were 2.3 and 1.3 hours, respectively.
63
0.8 r--.-------r-----,---r--....,...-----r--~-_,_-__, Observed Ul
a:
180 seconds
w ....
~ ~
-'
w ::> w -'
a:
w
~ 0.2 ~
'0
"
12
13
June 199,
FIG. 30. Differences In Water Levels Due to the Time Step, Pita Island
0.5 r-....,...--~-....,...--..----,---r---,---..---....,...--.,......---~
Ul
a:
....w
!!I~
0.3
-' w ::>
Observed
a:
'80 seconds
~ 0.2
w .... < ~
360 seconds
0.1
720 seconds
0800
1600
2400
0800
'0
'600
2400
,600
0800
2400
0600
12
"
'600 '3
June ,991
FIG. 31. Differences In Water Levels Due to the Time Step, Riviera Beach
1.0 C Z
0
U
i]j a: UJ
c..
Ul
a:
....w UJ
::; ~
~
g
360 seconds
-' UJ ::>
720 seconds
-1~400
0800
1600 10
2400
oaoo
,600
2400
1600
0800
2400
0600
12
11 June '991
FIG. 32. Differences in Velocity Due to the Time Step, GIWW at JFK causeway
1600
'3
64
1.0 r'---.----.---r--.,.--~--.,._--~--.---_r_---.--....,...-__.
180 seccnds 360 seccnds
720 seconds
'1.04OO,~----::-=.:-~::----::,:l::::-----:=:::--:-:!":::----::-:l:-:-----:-~---"""-...".J.--~-~_..J 2 0800 1600 2400 0800 1600 2400 0800 1600 2400 0800 1600 11 12 13 10 June 1991
FIG. 33. Differences In Velocity Due to the Time Step, South of Baffin Bay-Middle
o
4OOr------T------~I----~------r_-----r------r_,-----r------r-,-----r------
8 ~
a: 200 f-
UJ Cl.
...'" a:
UJ
~
Of180 seconds 360 seconds
-
720 seconds
14
13 June 1991
FIG. 34. Differences in Flow Due to the Time Step, GIWW at JFK causeway
o
4oo~--~--~I---~---r---T---r-'--~---~I---r--,
8
~200,.. ffi
n /""\
I~." r'\£\ A J
(;.\
180 seconds
-400
360 seconds -
f-
~
720 seconds
~ -~4'~00~--~172oo~--~2~4~00~--~'~2oo~--~2~4OO~----I~200~----~24OO~~--~1~2~00-----O'24OO~----~I~200Y>--~
....
I
10
11
'
I
12 June 1991
FIG. 35. Differences In Flow Due to the Time Step, Baffin Bay
13
14
65
Wind·Stress The value of the wind stress coefficient had the greatest influence on model results of any of the parameters evaluated. Figs. 36 through 41 show the effects of the wind stress coefficient on water levels at the Pita Island and Riviera Beach tide stations, velocities for the GIWW at the JFK Causeway and South of Baffin Bay-Middle current stations, and the GIWW at the JFK Causeway and Baffin Bay flow cross sections, respectively. Wind stress coefficients of 0.0001, 0.0015 and 0.0026 were used for the sensitivity analysis. The calibrated model used the wind stress of 0.0015. The wind exerts a noticeably greater influence over station in the southern end of the upper Laguna Madre. The RMSE's between simulated and observed water levels and velocities are shown in Tables 10 and II, respectively.
TABLE 10. Root Mean Squared Errors between Simulated and Observed Water Levels (or Simulations with DitTerent Wind Stress Coefficients RMSE (meters) 0.0015 (Calibrated)
0.0001
0.0026
Water Level Station Corpus Christi NAS
0.001
0.001
0.002
Packery Channel
0.043
0.036
0.063
Pita Island
0.036
0.032
0.044
South Bird Island
0.059
0.055
0.063
Yarborough Pass
0.067
0.091
0.054
Riviera Beach
0.124
0.124
0.135
El Toro Island
0.006
0.006
0.007
Average
0.048
0.049
0.053
Wind appears 10 cause very little change in the water levels at the Pita lsland station, which is strongly associated with the tidal signal from the Gulf of Mexico via Corpus Christi Bay. Larger wind stress coefficients actually increased the error at the three northern most internal stations. The error with a wind stress coefficient of 0.0 15 was improved by 2.4 centimeters at Yarborough Pass- The second increase of wind stress 10 0.0026 only reduced the error at the Yarborough Pass station. The daily variations in water level at the Riviera Beach station appear 10 be almost entirely due 10 the effects of wind. The model results for the Riviera Beach station with negligible wind stress, shown as a dashed line on Fig. 37, produced a water level time series with smooth. long period oscillations.
66
These °long period oscillations seem to correspond to the length of the lunar tidal cycle. A simulation run which spans several months to a year would be required to more conclusively evaluate this observation. The calibrated model with a wind stress coefficient of 0.0015 produced the smallest RMSE of the three options evaluated. Velocities and flows were similarly affected by changes in the wind stress coefficient. The prevailing southerly and south easterly winds generally caused an increase in flow and velocity toward the north. Simulated velocities were improved by the larger wind stress coefficients. A value of 0.0015 produced an average improvement of 0.02 meters per second, while a value of 0.0026 yielded
an average improvement of 0.03 meters per second. The improvement in velocities with the 0.0026 wind stress coefficient was ourweighed by the decrease in accuracy of the watez levels. The greatest effect of wind can be observed in Fig. 41, which shows the flow at the Baffin Bay cross section. The wind stress coefficient caused dramatic fluctuations in the flow which were not present in the results with a negligible wind stress.
TABLE 11. Root Mean Squared Errors between Simulated and Observed Velocities for Simulations with Different Wind Stress Coefficients
RMSE (meters per second) 0.0015 (Calibrated)
0.0001
0.0026
Humble Channel
0.13
0.18
0.11
GIWW at the 1FK Causeway
0.16
0.20
0.14
GIWW at Marker 199
0.19
0.22
0.18
North of Baffin Bay
0.10
0.09
0.10
Mouth of Baffin Bay
0.08
0.09
0.09
South of Baffin Bay-Middle
0.11
0.12
0.12
South of Baffin Bay-West
0.08
0.10
0.Q7
Nonh Land Cut
0.12
0.15
0.11
Avernge
0.12
0.14
0.11
Water Level Station
67
0.8 t --....,...--.-----,.---..,.--...---,-------.-----r----r--_---r---.-_ _~ Observed Wind Stro ••• 0.0001 Wind Stross • 0.0015
0~,-~-,2.-~~3.-~-4;-~-.5--~.6--~'7.-~'8.-~'9,-~~1~0~~1~1~--,~2.-~~13~~~14~--~1~5~ June 1991
FIG. 36. Differences In Water Levels Due to the Wind Stress, Pita Island
0.8r-------~--_r--
__----~--~__~___r--~--~----__--~--_r--
__
--~
Observed Wind
S~ess
.0_0001
Wind
S~ess
.0.0015
Wind
S~ess
.0.0026
0~~~~2.-~~3~~~4~~~S--~~6.-~~7~~~8~~~9~~~1~0~--1~1--~~12~~-,3~~-1-4~--,~5-J
June 1991
FIG. 37. Differences In Water Levels Due to the Wind Stress, Riviera Beach
1.0r---~----~----~-----T----~----_r----~----~----~----~--------_,
Observed Wind Stre••• 0.0001 Wind Stre••• 0.0015 Wind Stre••• 0.0026
-1
B•.L,00-:---~0~800:::----I-:-:800-!=--~2,-J400~----::080:'=:0--------:,~60':-0:---::-240:l::-:O----::0:;;800=-------:-;16OO:'=:----::2:-:400;;;;-----;;:0800:'=:--~1::;600=---....J 10
12
11
13
June 1991
FIG. 38. Differences in Velocity Due to the Wind Stress, GIWW at JFK causeway
68
10 Cl
~
(..)
w
Wind
.1~4OO
1600
0800 10
2400
0800
1600
2400
11
0800
1600
2400
S~e.s
0800
12
1600
13
June 1991
FIG. 39. Differences In VelocHy Due to the Wind Stress, South of Baffin Bay-Middle
June 1991
FIG. 40. Differences In Flow Due to the Wind Stress, GIWW at JFK Causeway
June 1991
FIG. 41. Differences In Flow Due to the Wind Stress, Baffin Bay
70
Simulations with the 25 percent reduction in roughness and the constant value of 0.030 produced an increase in the magniblde of flow and velocity in both the positive and negative directions. The variations caused by changes in the roughness coefficient were on the same order of magniblde as those resulting from use of the 720 second time step. Variation of the
fI
values had the
greatest impact at the Humble Channel, Grww at the JFK Causeway, and Grww at Marker 199 stations. Velocities were improved slightly at these stations. Reduction of the roughness in the tidal flats and non-channel areas evidently caused the improvement. The use of a constant fI value of 0.030 essentially increased the channel roughness and decreased the roughness in the tidal flats and other areas.
TABLE 13. Root Mean Squared Errors between Simulated and Observed Velocities for Simulations with Different Manning's Roughness Coefficients RMSE (meters per second) Varied 0.025-0.040 (Calibrated)
-25%
+25%
Constant
Humble Channel
0.13
0.11
0.15
0.10
GIWW at the JFK Causeway
0.16
0.14
0.17
0.13
Grww at Marker 199
0.19
0.17
0.20
0.17
North of Baffin Bay
0.10
0.09
0.10
0.09
Mouth of Baffin Bay
0.08
0.09
0.08
0.08
South of Baffin Bay-Middle
0.11
0.10
0.11
0.11
South of Baffin Bay-West
0.08
0.07
0.08
0.08
North Land Cut
0.12
0.11
0.13
0.11
Average
0.12
0.11
0.13
0.11
Water Level Station
69
Manning'sn
The values of the Manning' s roughness coefficient in each of the model grid cells also exens a strong influence on model simulations. Results for simulations with a range of n values are shown in Figs. 42 through 47 for the same observation stations discussed in the time step and wind stress sections. Tables 12 and 13 show the RMSE between simulated and observed water levels and velocities. respectively. Four scenarios were simulated in order to observe the influence of roughness on the computations. The calibrated model incorporated a spatially varied roughness which ranged from 0.025 in the aIWW to 0.040 on shallow tidal flats. The distribution of n values was similar to that used in the TxBLEND model. Scenarios two and three increased and decreased the spatially varied roughness at all points by 25% respectively. The fourth scenario employed a constant value of 0.030 in all computational grid cells. The results of the sensitivity analysis appear to indicate that additional modifications of the roughness could improve the simulation. The use of a constant roughness produced the lowest average RMSE and improves the error at each walef level station except for Paclcery Channel. The effects of the 25 percent reduction in the spatially varied roughness produced similar results. The greatest improvement was observed at the Yarborough Pass tide station.
TABLE 12. Root Mean Squared Errors between Simulated and Observed Water Levels ror Simulations with DifI'erent Manning's Roughness Coefficients
RMSE (meters) ·25%
+25%
Constant
Water Level Station
Varied 0.025-0.040 (Calibrated)
Corpus Christi NAS
0.001
0.001
0.001
0.001
Paclcery Channel
0.043
0.048
0.040
0.048
Pita Island
0.036
0.038
0.036
0.035
South Bird Island
0.059
0.052
0.065
0.053
Yarborough Pass
0,(>67
0.060
0.072
0.055
Riviera Beach
0.124
0.120
0.128
0.118
EI Toro Island
0.006
0.005
0.006
0.005
Average
0.048
0.046
0.050
0.045
71
0.8 r·--.----.----,---.....----,....----,r---.-----,.--,----,....--.-----, ObselVed U)
::5
Varied n -25%
0.6
i;:;
Vaned n
UJ
Constant n
Vaned n .25%
.....
> W ..... a:
UJ
~ 0800
1600
2400
0800
10
1600
2400
1600
0800
2400
0800
12
11
1600 13
June 1991
FIG. 42. Differences In Water Levels Due to Manning's n, Pita Island
0.8r---~----~----r---~----~---,----~----~---,----~----~~ Observed
Vaned n -25"'0
U)
a: w
Vaned n
~ ;:; .....
w
> W
...J
a:
UJ
'
_ ,,~:...
~
~.-
§
I'~~V"A
~..
....
\,I,j
cr \,I,j
i June 1991
FIG. 55. Comparison of Water Levels at the Pita Island Tide Station
83
1.0
1 - ........-___.--..--........-___.--.._--.----,--...-_-.-_ ___.--...---.----, SWIFT2D
Observed
-
TxBLEND
uo
~
~
.... w >
W ...J
c: W
>-
~
-0.4
2
3
4
5
6
7 8 June '991
9
'0
"
'2
'4
FIG. 59. Comparison of Water Levels at the EI Toro Island Tide Station
Table 16 shows the RMSE's between simulated and observed water levels for both the SWIFT2D and TxBLEND simulations. Water levels at the Yarborough Pass and Riviera Beach stations did not malCh as well as the water levels at the northern tide stations. The differences seem
to
arise from the simulated wind effects in the models. The influence of wind appears to be smaller in the TxBLEND model. The RMSE's from the TxBLEND results were larger at the South Bird Island, Yarborough Pass and Riviera Beach stations, while the TxBLEND errors were smaller for the Packery Channel and Pita Island Stations. Additional adjustments of the wind stress factor in the TxBLEND model will probably improve the simulation of the lower three internal station. The effects of wind on the simulations are discussed further in the sections which describe the velocity and flow comparisons.
TABLE 16. Root Mean Squared Errors between SWIFr2D and TxBLEND Simulated Water Levels and Observed Water Levels RMSE (meters) Water Level Station
SWIFT2D
TxBLEND
Corpus Christi NAS
0.001
0.039
Packery Channel
0.043
0.032
Pita Island
0.036
0.029
South Bird Island
0.059
0.068
Yarborough Pass
0.067
0.081
Riviera Beach
0.124
0.128
El Toro Island
0.006
0.004
Average
0.048
0.054
85
Velocity The velocities simulated by SWIFT2D also were comparable to those from the TxBLEND simulations, however, a consistent phase shift was observed in the timing of velocities at stations distant from the NAS driving tide. Figs. 60 through 67 show comparisons of simulated velocities at the eight locations shown in Fig. 13. The simulated velocities at the Humble Channel and GIWW at . the JFK Causeway stations matched well in regard to both phase and amplitude. These stations are located near the NAS driving tide and are not significantly affected by wind. The phase of the SWIFT2D simulated velocities show a noticeable lag in comparison to TxBLEND velocities at stations south of the GIWW at Marker 199 station. The phase shift is consistent at around six hours. This shift is even more noticeable in comparisons of simulated flows discussed in the following section of
this report. Velocities at these southern locations are strongly dependent on the influence of wind. The observed phase shift was discovered to be the result of a simple problem in the input of wind data in the two models. The tide data used in the simulation was referenced to Greenwich Mean Time (GMT) while the wind data received from the National Climatic Data Center (NCDC) was referenced
to Local Standard Time (LST). LST for the Laguna Madre study area can be obtained by subtracting six hours from the GMT. All tidal and wind inputs in the SWIFT2D model were adjusted to GMT. The TxBLEND model used GMf for the tide data, however, LST was evidently used for the wind data The resulting six hour difference corresponds directly to the observed phase shift observed in the velocities and flows. Velocities simulated by the two models were very similar. Table 17 show the RMSE's between simulated and observed velocities for the SWIFT2D and TxBLEND models. The average difference between simulated and observed velocities was 0.12 for SWIFT2D and 0.13 for TxBLEND.
TABLE 17. Root Mean Squared Errors between SWIFr2D and TxBLEND Simulated Vehx:ities and Observed Velocities RMSE (meters per second) SWIFI'2D
TxBLEND
Humble Channel
0.13
0.14
GIWW at the JFK Causeway
0.16
0.15
GIWW at Marker 199
0.19
0.19
North of Baffin Bay
0.10
0.09
Mouth of Baffin Bay
0.08
0.09
South of Baffin Bay-Middle
0.11
0.14
South of Baffin Bay-West
0.08
0.10
North Land Cut
0.12
0.13
Average
0.12
0.13
Water Level Station
86
1.0' 0
SWIFT2D
()
Observed
~ w
U)
a: w
aU)
a: w
fo-
0
'3
ll:
>f0- -0.5
g -' w
>
-lg4OO
2400
1200 11
2400
1200 12 June 1991
2400
1200
2400
1200 14
13
FIG. 60. COmpariSOn of Velocity at the Humble Channel Station
1.0 SWIFT2D
0
~ ()
Observed
UJ
U)
TxBLEND ~:"'.:.;::..:.~'"
a: w
a-
,if'
U)
c: W
........._
fo-
\OJ
:::!i
ll: ~
8 -'
UJ
>
1200 10
1200
2400
2400
1200 12 June 1991
2400
1200
2400
13
1200 14
FIG. 61. Comparison of Velocity at the GIWW at JFK Causeway Station
1.0 0
SWIFT2D
0
Observed
U)
TxBLEND
z
() UJ
a: \OJ
aU)
a:
UJ fo-
\OJ
:::!i
ll: >-
§ -' w
>
-lg4OO
1800
0800 10
2400
1600
0800
2400
1800
0800 12
11 June 1991
FIG. 62. Comparison of Velocity at the GIWW Marker 199 Station
2400
1800
0800 13
87
~u
\.0 ['--,.----,----r---,-----.---r---,-----,.--,---,---,.----.., SWIFT2D Observed
~ O.S
,,~4OO'L;;;-~0n.8:;;00;;----:,~6~00;----::2;:t4OO;;;:;---;;0-;;80;;;O:-----;-'60=O---:;:24Of;;;::0-~0:;;800=---:'~600=---=2.,J;4OO:::---::-0800:':-:---'600='=-..J 10
12
11
'3
June 1991
FIG. 63. Comparison of Velocity at the North of Baffin Bay Station
,
\.0
T
SWIFT2D
0
~
Observed
u
'OJ
U)
051-
TxBLEND
0::
-
u.J
ll. U)
0::
w
o.
-.-.-.-:.-.~,.
-
~-.-=
'"\,r-
~
UJ
::i
./
~
-
~ ·0.5 '-
8--' w >
'\.~4OO
I
1600
0800
2400
1600
0800
2400
2400
12
11
'0
I
,600
0800
,600
0800 13
June 1991
FIG. 64. CompariSOn of Velocity at the Mouth ot Baffin Bay Station
1.0r--~~-~---.--~--~--_r--~--~--._--~--~--.
I
SWIFT2D Observed
TxBLEND
-
-,~4OOL--0-800~--,-600~-....,2,.J4OO '-:---08OO..,....,--,.,.600:-:--..,.24OO.J,..,.--0800-::-:'-::---,-=600~--::2..l4OO:-:---=0800-=---:-,600=-10
12
11 June 1991
FIG. 65. Comparison ot Velocity at the South of Baffin Bay·Mlddle Station
13
88
1.0
r--.---...----r--...----.---.----.---...---,--,--.-----...., SWIFT20 Observed TxBLENO
10
12
11
13
June 1991
FIG. 66. Comparison of Velocity at the South of Baffin Bay-West Station
1.0 SWIFT20
0
~ U
Observed
a:
TxBLENO
~ 0.5
il: rn
a:
w w :2 >-
0
~
~ -0.5
8....
w
>
-1~4';;;OO;---;:;0;;;800;;;---;-;1600~--;2>!400;;;;---;;;080=0--:1::;60;;-;O:---::;'2400:--;0800;:;';;:;:--~1600=--:2,..:4QO=---:::0800=--:-::'600'::=--...J 10
11
12
13
June 1991
FIG. 67. COmparison of Velocity at the North Land Cut Station
Flow Simulated flows were compared at the eight cross sections shown in Fig 14. There were no measured flow data available for these cross sections during the time period of the simulations, therefore, the comparisons are based solely on a comparison of the flows simulated by the SWIFT2D and TxBLEND models. Figs. 68 through 78 show the SWIFT2D and TxBLEND simulated flows at the eight cross sections.
89
200
~~/'\l\ (\ I"/\ ~f \ ~ I \ \ f \\ i,l' 'I\'J \. i
O~ f
\..', .,
~
\'{
"
'~t,
i
\~,I
'1.../
f
~
.,
\:
I \',
!\
~~
,'I
\1' . t~\a [,.~ .
Ii \ • ,\
W
Ii
"l'
I //
i{,l '\ ;'llii
TxBLEND
/t \\I',. \\1\
I,
rfi, ~'
,..
(,\ {,\
J1 ' i ' ,\,
I!
~I .,', ~'\
t. SWIFT2D
h
t~\
.r,
{..,. .,
,f\V'., \\..: ...~ J~' \.1 ~~\'1' II\..
i. , \i!"~1 ..,. .
I:~,
I'/f.! ~J
I
"
~
~,1
y! ~j
'\
Ii
",.
\.
\\ II
i,.
~ ~ .4oo~-'--~~2'-~~3'-~~4'-~-'5:-~~6--~-'7--~-a'-~~9'-~~I~O--~7,~I~--7'2~~~13~~~1~4-J .J
~
June 1991
FIG. 68. CompariSon of Flow at the GIWW at Corpus Christi Cross Section
June 1991
FIG. 69. Comparison of Flow at the Corpus Christi NAS Cross Section
June 1991
FIG. 70. Comparison of Flow at the Packery Channel Cross Section
90
June 1991
FIG. 71. Comparison of Flow at the Humble Channel Cross Section
Cl
is
.1"\
(J
a. '"
fi' \" ! "/\' ! ~,i 'f-' ',' ','\ i' ',",
i:!:!
J
~
c:: 200
~
7
,
0
W
: :;
t/
-,
I'
i \ ,'i
~
,,~
\I
'v,il 1"1
r
i,J
as
() ,200
'l . . ~.
r' ",'\
~,
U :=I
i:
,,' ," / I,
/400\ " -~'t,-,,7'''''-A ,,,;, J"
I,~'... \t"
"\J
I·,
• \
\\,..
\i \U\ y:
SWIFT2D
TxBLEND
,jr: I
\,., ~'(J "\ ..,
I '.
" i,. t
\
'i" \}f"
"
'-1B2. Austin. TIC. 265 p. U.S. Departtnent of Commerce, National Ocean Service. ''Texas. Intracoastal Waterway. Laguna Madre. Chubby Island to Stover Point, including the Arroyo Colorado." Nautical Chart 11303.
Edition 17. Washington DC. August, 1992.
111
U.S. Department of Commerce, National Ocean Service, "Texas, Intracoastal Waterway, Laguna Madre, SlOver Point to Port Brownsville, including Brazos Santiago Pass." Nautical Chart 11303, Edition 24, Washingron DC, March 19, 1994. U.S. Department of Commerce, National Ocean Service, ''Texas, Intracoastal 10
W~rway,
Redtish Bay
Middle Ground, including Baffin Bay." Nautical Chart 11308, Edition 18, Washingron DC,
April 16, 1994. U.S. Department of Commerce, National Ocean Service, ''Texas Intracoastal W~rway, Carlos Bay 10 Redfish Bay including Copano Bay." Nautical Chart 11314, Edition 18, Washingron DC, July, 1994. U.S. Department of Commerce, National Ocean Service, ''Texas, Intracoastal Waterway, Laguna Madre, Middle Ground to Chubby Island." Nautical Chart 11306, Edition 18, Washington DC, October 15, 1994. Westerink, JJ., and Gray, W.G. (1991). "Progress in surface water modeling." U.S. National Report
to International Union o/Geodesy and Geophysics 1987-1990, Reviews o/Geophysics, Supplement, American Geophysical Union, 210-217.
112
APPENDIX A
SENSITIVITY ANALYSIS
113
EFFECT OF CHANGES IN THE TIME STEP ON SWIFT2D SIMULATION RESULTS
Ol.r----.-----.----,-----------,-----r-----.----------,-----.-----r----,
..
~
~
......... ,.........
-,
~
~
··tr--~----~---r--------~---,------------_,--------~--.
_OM
o.
12"
~ ~
;j 02
>
i
I" I...
.... ,.
,lOG
.
.... .... ,... ... .... ./unIi'.'
"
... ....
,
'''''
'J
.... .. ,... ,...
"'"
... ,... ....
,..., ,
,
....... 'Wh
"
"
·'r'---------------r----------r----r---------------r----__----____,
""'"'1110 _ _ _ ~
'"'-
~
~ O.
..
~
~" ~ ~
~ 02
~
""'"'-
~o .,
~
S 0" I...
.... ,.
,100
.... ....
'''''
.... ....
... .... "
,
,lOG
"
"""QIIiII
'
FIG. A-4; DIHerencea In Walar Leve .. Due 10 lhe 11me Slap. YarbolOugh Pa.a
O.jr----r----~--_,----------~--_,-----r--------_,r_---r---------,
,.
'
01
I...
'''''
FlO. A·I; DIH_1n W.lar Level. Due ID the n .... Slap, Packery Chan....
i
""--
is
~
~
.-... ..... -....
~
~
,lOG
I...
11 0_ ._ lIO _
720 _ _
.... . ,... ,... .... ,... .... .... .....,.'.1
,...,
"
.... ....
FIG. A-5; DIHere""" In Waler Levels Due 10 the 11me Slep. Riviera BelICh
FIG. A-2; D I H _ In W.lar Leve .. Due 10 the n .... Slap, Pita ..land
,aoo
"
··rj----~------_,----~--------,_------------_,------------__,
..'"
.........
""'"'-
,
~ ~
~
liIiI_
..
~ ~ ~ ~
-
---
'''-
'I" " 6100
_
..
I"
2_
1_
_
"
2_ .;un.liIi'
0100
,.
1600
2~~600
"
FIG. A-3; DlH........ In W.lar Level. Due 10 lhe nme Slap. Soulh Bird Island
-"'"
'.[r---~----~--,---------~---.----~----~---.----~------_,
,Qjr---_,----~----_r----------~----._----,-----r---_,-----,-----,----,
~
10$
· 01 ~
!
~~•
8
os
•
,,~ LI
Vf
.
'i
§ e
•~
;.;
~
!2 II.
~Ir---r---~--,---~--~---r--~--~----,---~--~---r--~----r--,
iL~f._·vj::...·v. l\J_~:;.\,,J :-F\,.~. r
5
-fj
!
.
..........
----- 1 8 0 _
120._ _
.,~
a.o
,.
1tcio-- 2.00
...
1100
2400
0100
20100
1100
......",.,
"
1100
0100
c.oo
2400
200
~
.00
~
"~ ~
~
r'" •
J
-\f.:.. . ~.
'
~,.
~200
Ii
\..
-Ii t .'
\"""Ji ',j
~/.
\
!
I!i~\' . If~,' .
,-7'\., '..
I'~\~
\\
\ \\
i.
~1 .
'" ,J
\.1"'
\\
""_. 11O~1
120
....aano.
.. ~-.-~-.-~--~--~-.....,..,.,
,.
12
"
FIG. A-14: Diller_In Flow Due 10 the TIme Step. GIWW al Corpus ChrleU
13
FIG. A-17: Difference. In Flow Due 10 lhellme Step, Humble Channel ~rl--~--~----r---r---,---,---~--~---,----r---r---r---'---~--,
t/""\ .t7'-~\ j'~'1\ ~'O ~v.. I '.~) ;.)1 Jlr'''' 1\ J; ! _ ,. ~~~
L.
:i/ ,.! 1I1/
• _
Ii
'
.
0
V/
/:'i
I
,.
"
\ l
-
•
110 NWI"M
..
JtiO_
I~ "~
,/---:"
i~
~
..
/~:-~
... "
, , __ .... ". • -
J'J'".... '
ji'
\.
{/
.""
•
/~;~
" ~,,,., "I , . " '~".~..rI' \_''-~-'--/"p
.. ' \
,.,. ,
~",!,--
,.:--_.\
v
'J ~
~
CNlO§ 'IUd SW:U~ NI.wXIl3A
, ,,
,
;
; ;
I
•
... ! 3
,, j
:
I
'" ,. . .t::-'::,i'"'\.,' ,- .. ~,--.' \/"r... _,.'./ ... ..
-
•.
W"..5u_~OOOOI
~ ...
w.naSlr_.OOOI'i WIpos._~o~
aoo!
10
12
13
14
..kMlIllllil
FIG. A-4a: DIII...nw8 In Flow Due to lhe Wind SI..... Lilt
Gr. .n Hili
____--__--__
o. North Land CuI
--~--~--_r--_,
V
,
WtncI su..... 0 0021 1
Il10
__,,__~,.-__ • ,,,.-__~,,.--,,~,__-.,•..J
~wtfl·II\A u ~ i~ ~
~.,.
•
l' .,
t,
~r,----~--~---'----,----r----.----r----.----r----'---~---'----'----,
J
.-
...,. 1IIIU
~
/...,
~:)\ti"
FIG. A-47: DIII...nce.ln Flow Due 10 the Wind S....., Lilt "' Yarborough PI"
~.,. I.',"'"'1"C""~h'¥~~"" , ..,/~..(",f' '·.it;"';"y:, ~ .:'.; ,,':'" W~,,'/ ~ftu. iM • . / \ / \ , / ' I; ,-~,. -V V'"'1,\."-"\ ,.:~¥IV. \j \_. 1..1 o VI ",,_ ! ,.......... ,t/t.;:..,. . ...,.;~ .
;.~:1ij~.
~ ...
ir"'l I' l''\
•
.~. (~,f\iff~. rf1~'' ~ -r-·..... H ,-1 \ ' \\1"'\
IX
i"\
II:
-----
'..,
.J..neUIiU
"
~
WsncIsu.... OOOO, .......... Wonas..... OOOIS
\f\
... LI~____,-~-.__~~"-"__-..-"-"->-.~
1•
FIG. A-44: DIII.rence. In Flow Due to the Wind SItMa. UI at South Bird Island "Ir---~--_r--
,.Jo.., •• _
WIIlO5&r. . . . 000•
'0',1
__--____________--,
!,
~~ ~ .~~,! ~600
"
FIG. A-56: Dlff_ncaa In Velocity Due 10 Mannlng'S n, GIWW Marker 199
"
V.. ..an 25,
~ H -os
~
,~
.... ,.
-
".,4Cln
-
V¥....:I n .25,.,
~
.... " ,~
~ .A.nIo'.'
.... "
'...
FIG. A-59: Difference. In Velocity Due 10 Manning" n, Soulh
~
.... "
C.nnal&llltl
0' Baffin Bay-MIddle
.......
!:::l
128
• ~•
~ c
• ~ ~ , , I ;, , , ! I :, II !
I
c
1
.
,
;; ~
I
c
I ~
I
!'0 j
c
c
~ J >I
i
1
~
,, ,
I,
,I
!
.
:
J
j
c
I
12
,II !
I
~
i1i > 5
>
I
~
= ~
f
~
,• I
L
s
§ !
!
is
!
o-2'
!
g
ONO:J3'S ttJ-' SHUlPIJI W:xll'JA
~
c
,i ~
:; (J
~
§
I
I
I
= ~
!
s, , I I
0i-cl ! lj
,
~ § i -
I
~
.
.
CNXJJI IIIlIII SH;llJ'I /II.w:J01~
J
is
:c:J ~
ii:
/:.{V
... lr---,----r---.----.---~--_r--------~--_r----.---~--_r---,----.-__,
~r,--~---'----r---~--'---.----r--~---,----r---~--.---~---r---,
§200
~~.
.
i~ "" '~ :~\ '..." ~
.;._.,:1,
"r.
Q
'00
..
~
, M";< •
."--00
MIlO
IllIG
2*
OIDO
10
,_
211QO
OIDD
11
1100
.a.oo
"""""" ,
...
1100
2400
lI:f.!x,
OIOD
1~
12
'\...
0100
'4
...,.1111,
FIG. A~: 0111...""". In F_ Due 10 Manntng'. n. GA)NW al Corpu. Christi
~ ~
~
,
it
"'.. ..uo
"
...
-.. ... - ... '....
,
,
~
II.. * , n ~l$'lI.
21MX1
0IKlI
,_
2"'"
oeoo
12
"
1Il00
2.00
OMO
13
~
3, ~
0100
1100
2~
0100
l~
1100
0100
2~
'600
otoo
1100
"
"
~'~I
_.~
\'>A",;.."
'i;::~7\.
1.'\
WO-.-n .210..
OIQO
1100
2.00--
_
1100
2«)0
0100
1800
2400
otoO
12 ........ 1ge1
1100
2..:00
0100
1100
2400
0100
IllIG '2
.............
2.Go
~
----- \/.,1«1 n -25'11.
.....,.0
1000
QIOO
2~
lJ
FIG. A-64: Dllla..""".ln Flow Due 10 Manning'. n, PlICkary Channal
2400
OIIXI
1600
.oorr-~~~~-'---'---'---'---'--~---'~~--~---'----------'
~~ ~ ... ~
~
~
~200
~
J"
,.,,~~ I/~::;,'//-:::'.......
, '. ' ''-V ''
.. -/....... _..
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1800
.. -
----- v..-tI 2S,.,
,-"
/
-
V_".2S1Io
c..-o,"
con'~(1
10
ltoO IJ
FIG. A-66: Dine.....,.. In Flow Due 10 Manning'. n. GIWW al JFK Cauaawav
.... ,!td n .250","
0.00
.
"""-, 10
~"~,
-'00
'5f1
... 4iOf.ao
,800
t::~:\..r. .r~;;::::~
..,
--.;
----- , . - , .... " ......an
JunIoHiJlU
t-/.~lZ0:;c:'; 'it 'YV ~
'[. .
~
2400
.~
14
IWIr---,----r---,----.---~--_.----.---~--_r---,----.---_r--------.-__,
t
1eGO
c.o......,
FIG. A-63: Dille..""". In FloW Due 10 Manning'. n. Corpus ChrlaU HAS
I
"_n.~""
ean.lOIflln
/V(.~.;:.. c: ;~ .''''', ...' ..' ;--;;\.. L0 . . ! - ~j" "~V' ~ "
~
r
..
,-,
~200
~-
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'
"',r---r---r---r--~--~---r~~--~---,---r---r---,--~--~--,
ill
~~
----. , - ,"~ ,
/
,.,I
c::;>
----.
.
Va.HtO n -25'11.
v.....
-"-'
lIan_n
-
.~...
eon...."tl GIDD
ItOO
2400
0100
10
1100
2400
1100
OIOQ
2Il00
,.00
CIIGO
....... ,.,
"
12
20&00
UIQO
OIOQ
I:)
... ,...
,
I.
.....
... ,...
,
Il ..... ,1181
.....
... ,... .... ....
, 13
FIG. 1.-71: Dlff.rance. In Flow Due 10 Manning'. n. LU at YarborQugh P...
~... I~~~V\:t~w~·-·l;:;}.~~1:-.~~ ~~ a .___. -.¥.~ .-.-.~.c~< ---:r::--
'"~"" II!
Iv'
..... .... ,... .....
"'
1000
MO,r----------,r----------,,----------,,----------,,----------, ~ ...
\ .......
•
13
FIG. 1.-68: Diffenlllce.ln Flow Due 10 .....nlng·. n. LU
~...
1I.lIIIIn
~ ~
~
r'"
'"
II.,.., n -25"
'"
»>,r----------,-----------,-----------,,----------,,----------, L~ :II
----- Vlfoeon -25'"
" ...an
~
II:
i!
V.... n.25'to 1(1O~
_A""\."'_~' " /~f"':'"' - -to6;:'-~ "" •. ' • .
_,
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~
- - - C-.-.n
f),
of/AV"--.'
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._ 10
2tOO
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1100 11
2400
0100
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12 J.,ne1881
-V
2400
OIGO
1100
'V" f;··;
-
2400
, /,'
0100
1Il00
Il
FIG. 1.-72: Differences In Flow Due 10 Mannlng's n. LU 81 North Lond Cut
FIG. 1.-68: Dlff.rance. In FlOW Due 10 MannIng'. n, LU 8. Green Hili
.. r'--~--~---r--~--~---r--~--~--,---~--~--.---~--~--,
~
:II ~
If
12
; L~ I ~- t "4410
lIan.. n lI'_n.25...
0100
.a
1600
2~
0100
1100
"
2~
GIDD
1100 12
....,.'.,
2~
-_. 0100
1100 13
FIG. 1.·70: Dlfferance.ln Flow Due 10 Manning'. n. Bailin Bay
11:.00
0100
~
-
Ul
o
131
EFFECT OF CHANGES IN VISCOSITY ON SWIFr2D SIMULATION RESULTS
O·rr----,-----y-----r----------,-----r-----.-----,----;r----,-----,----,
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No.-.aWKMWI
,...,
'f...
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FIG. A-l02: Dlnereneeln V.loGlly Due 10 the Advec:11on OpUon, H..mble Chan....
- ... .... .... "
'
Jo.tnaltil
••
... .... .... ,...
'
,J
fiG. A-l05: Dillerenealn Velocity Dualo the AdveCl10n Opllon. North 01 Bailin Bay '·r'-----r----~----~----.-----c---_,-----,-----.----_r-----r----~--__,
'·r'----~----,-----~----.-----r---_,r_---,----~----_r----~----~--_,
! ·
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os
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r
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NO .....
; o! • § •• i
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,. '... .... .... ,... ... .... ,. ,... ....... ,...
'fL... .... ,.
,J
.....,.. 1.,1
FIG. A-l03: Dlner.ncu In Veloclly Due 10 the Advec:Uon Opllon. GlWW.1 JFK Ca....w.y
.
... ...
,
,
--..-.........
- ... .... .... "
'
""--
...
,NOAdo""_
... ,... .... ,...
,
~
Jwla •••
_.
"V
'J
"
fiG. A-l06: DIII..enc:ea In Velocity Due 10 .... Advec:Uon Option. Moulh 01 Bailin Bay
'·r'----~----,_----r_----r-----r---_,-----.-----r----_r----------.---_,
!• .. » i~ t=::
--------v-
§
"'[~--'-----"-~'--'---~==::
ill E
r
r
___
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V-
fi ••
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L_
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ND"-""""
,.
II~-~
z~
0100
llilO
2~~-~
.........,
Il
~
.
~ -,
14100 Il
FIG. A-104: DI....nc:e.ln Valoc:lly Due 10 the Advecllon Opllon, GIWW .....k.r 1911
~
•
-
...
,-
B i
•f:OO----_--------,a--2~--_~--2~_-_;_aoo--z-~---- __ ________'__'OO_ '0 II .z 13
M1e1.,
FIG. A-l07: Dillerlncalin Velocity Due 10 Ihl Advection Opllon. So .. th 01 BaIlIn Bay-M
..-
w
10
~
r!11,J I
i,
.. ..= :>.
01
~
I
i
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a 5::J
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~
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:II c if
c It
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;
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- ... ..... - ... .... -. ... .... ,
,
,
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1100
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2.00
0100
'lOG
10
"
.JunIIlliel
2..00
0100
'IOO
hOO
1100 - ltOa
OIQO
12
II
'4
~I.I
FIG. A·IIO: DlllilrlllCMln Flow Due 10 lhe AdvecIIon OpUon, GIWW aI Corp... ChrlaU
FIG. A·113: Oillerencealn Flow Due 10 .... Advecllon OpUon. Humble Chilnncl
...
L.
K II
c
~
II:
I
11 I!! II
;
•~• :XY... _
,_
ZG
GIGO
10
ItIII
I..
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'Il10 1.lI
"
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..-
1100 l400-0100
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i ul "'f...
UIOO
... ....,
,
-
11
. - ... .... ......... ....
.... ...., .... .... ..., 12
..w..1 ••
,
~
,
Il
FIG. A-114: Oiller.nce.ln Flow Due 10 .... Advection OpUon. GIWW al JFK C.uaawa,
....
I
K :I
II
•
c
-
10
'4
~I.I
FIG. A·lll: Dllleranca In Flow 0 ... 10 .... AdYeclion OpUon, Corp... Chrla" HAS
,-
'..,./
ri--~--~---r--~--~---r--~-------r-------r---r--~--~--,
t
It I!!
I!!
II
I~ ~~. I"~
----. A,_.
'"..{"J
I.~""
- - --.
I_~GIGO
OICIQ 10
'11m 11
, ...
GIGO
1100 II
NgA4\r"" ....
l~_,WG-ltoo-·-_--,iiOo I;)
~Ultl
FIG. A·112: DlII_ _ 1n Flow Due 10 .... Aclvecllon Opllon, Pecllery Channal
II
§
•
.. _---
~
.,~~
-.-10
,-.Qg--z400~_-1~-'-2:oo~_~----r400 12
..w.'fIIII'
0100
1100 II
2400
OIOQ
.
FIG. A-lIS: Olll.rencealn Flow Oualo .... AdvecUon Opllon. LM al Pllalaland
,..- . J
...,. .J>. .....
o»,r---,---~---,----r---'----r--~----'----r--~----'----r--------'-~
~
·• ~
o»rl-~-~-'--~----'-~-~--'-~-~-r-~_~_~
~
...
:I
r
• It
i
~
~
~..... ~
. -.
,,-
,..,
~"""K_
l.:a.
..
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2"
2*
a.oo
12
1\
"
1100
OIOQ
June;
ItoG
l _ _ ....
~
... ,,0r01QQO
l~--,*,,;A~,... ;;;;---'
Il
I.'
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~ .... "~~Qi2Zio
'4
0100
IIOG
2~
oeoo
1100
ltOO
.-'100
"
"
2.00
....
OIOQ
"
~IWI
FIG. A·II&: Diner_a In Flow Due to lhe Aclvec:1lon OpUon. LU 81 South Bird laland
FIG. A·119: Dlnerence. In Flow OualO lhe Advection DpUon. LU ~I Yarborough Pae.
O»rl-~-~--r-~-~-"-~-~-"-~-~--r-~-~-,
lQQlr-~-~--r-~-~-'--~-~-'r-~-~--.-~-~-,
I· !
L~
· :II It
It
~
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i
;
•~
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.,...
. _.
..
M
I
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,_ 10
2...
MOl
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2.... ---..
11
1100
2_
1100
OIOQ
12
l4GO
OIIID
,_
IJ
,-
~ ... -~
2
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Survey
-1J;00
Survey
Observed
Observed
Nautical Chart
Nautical Chart
1200 10
2400
1200 11
2400
1200 12
2;00
-1.~;00
1200 13
1:m 10
2400
1200 11
2400
June 1991
~
g w
>
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'="',,.,.J' . . "..... -
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iii
w
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-· . . . , ~';':;I{.-\ ,
I ~•
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...,
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....1
... \..'
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-
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-
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•
. ,~.II' ,,
~
w
Simula,ed
a:
Observed
1200 10
24'00
1200 11
2400 June 1991
---~
1.5r'------r------r------r------r-----,------,------T-----,
-
0.5
-0.5
1200 13
FIG. 10. Brownsville Ship Channel
1.5 rl----,-------,---__,-----,,---r---,----.-----,
i
24'00
June 1991
FIG. 9. pon Isabel Channel
1.0
1:m 12
FIG. 11. South Bay Pass
1200 12
2@
1200 13
-1 J400
1200 10
2400
1200 11
2400 June 1991
FIG. 12. Brazos Santiago Pass
1200 12
2d~
1200
13
300rl---r--~--~r---r---r---~--'----r---r---r---'--~r---r---'
200
~
iJ)
100
~
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9 u.
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r\\. r, • ,,'"\1
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\
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\!,I 1t.!Io
Mi'r,1\, ', I ,~,\1 • 'I...,,
t r~
.
I
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1
,
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II I I
,
\.iii "\..,'.\.\ "1/\[1 1M" " ,
AI~"I >--., ~.
..... -
-0.5
Ir.::~)ra. .
•
r.';::::~·-· . . . . '.-
~.
.'-t • •" " .,~--~. ........
, . . . --:f.'
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/~'::"-'~'". .:\\
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l'----;~\
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.
fi'---~::\
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w
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-
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-1.~400 t
I
2400
1200
2400
12
Survey
-1.0 f-
1200
•
, Observ~
1200 10
13
,
2400
,
I
1200 11
2400
June 1991
I
1200 12
2400
1200 13
June 1991
FIG. 6. Old causeway (Mid East)
FIG. 5. Old Causeway (Eastern) 1.5rl-----.------,-----.------,------r-----,------r----_,
1.Srl----~------r_----,-----_r----~------r-----~--__,
1.0
~
~
~
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w
>
>
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ii'
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Ul
Ul W II:
w
II:
- - - - Observed
Survey
-1 ~4oo
1200 10
24'00
1200 11
24~0 June 1991
FIG. 7. Old Causeway (Mid West)
1200 12
2400
1200 13
,r=.,"-
,,.....-"- •
!i
---....
..'''\c.-.,"/.,N •
• •
-..,
i/
...._-',
-1~4oo
•
_ .. _... '
•
-
Observed
1200 10
2~
1 24 00
1200 11
June 1991
FIG. 8. Old Causeway (Western)
.. -
'-i
\ -.In~'I i, l
-1.0 ~ _._._ .. Naulical Chari
Naulical Chari
V\
,._--11
~
//
~:5 -0.5
~
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-
O.Sf-
1200 12
24'00
1200 13
1.5r'----_.------~-----r----_.------r-----,_-----r----_,
~
1.5rl----~------._----,-----_r-----.------r_----,-----,
~
~
~
g
~w
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w
>
>
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~
~
Vl
Vl
Survey
w
Survey
!I!
a: Observed
Observed
Nautical Chart
-1~4'oo
1200 10
2400
Nau'ical Chart
1200 11
2~
1200 12
24'00
1
1200 13
-
~;oo
1200
24'00
10
1200 11
2400
..me 1991
~
1.5rl------,-------r-----~------,_------r_----_,------,_----_,
..
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~
iilw
~
-
.
f-
.i,"~; ~~ ~~~I\' \-"''''/::..... \;~
o '. -0.5
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r"
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r.,.S
"'...........1 '
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.,i...·_·#,'.':... \,.\ '.. ,J;,;;r-,.,. t. '.~_ ~!-~'\4. , ' ".... /1i ',J,f"! •.
.....' :
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Vl
a:
-1.0
~ ___ .__ .
-1.~4'00
•
w a:
Simulated
-
Nautical Chart
Observed
1200 10
2400
1200 11
24'00 June 1991
FIG. 11. South Bay Pass
0-t 11\
1200 13
FIG. 10. Brownsville Ship Channel
1.5rl------r------r------r------r----~r_----,_----~----_,
~ 0.5
24'00
June 1991
FIG. 9. pon Isabel Channel
1.0 f-
1200 12
1200 12
2400
1200 13
-1~400
1200 10
24'00
1200 11
24'00 June 1991
FIG. 12. Brazos Santiago Pass
1200 12
24'~
1200 13
~"''''',\
300
200
't!
~
~
0
-100
\~6J" \; ...
"~ , \' , ,)
~
n
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I" I:'I',, J r-l1
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l ~,
1 500
', ",\ "i''''• M."·...'i •..."
It\
~ i
100
~ o'?:
u:'
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~,.l,'rJ'I· ~1':
'
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,
~
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Naulical Chart
, 1
~ ~
~
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~
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,I I . A.
• A.~, I
u.
V
Survey .-.-.. Nautical Chart
-200
2
3
4
5
6
7 8 June 1991
9
10
1I
12
13
.....
2
14
3
6001- ~ I i! i!
\' -200"
II ,
~
U f
-\i~ \' ~
J ,
3
4
5
, 6
• 7 8 June 1991
FIG. 3. Port Mansfield Channel
'
I . 9
If A , ~
Y
10
13
r, , , . 1 11
12
14
_._._..
12
13
14
,
r:
~
Nautical Chart
~
~.' .I'~!i I
~ I.: Ii! ,W m I
II III\} \1\
. H, ' ' '
J
1t
t -:-.-.', Nau~caI c~art. 2
'-l
11
----- Survey
l' ,I", • IiI.J,! !iii
~.•! .~,'.i 'il~
----- Survey
0-t.
10
~ ,.
I
-600
9
800
400
~
7 8 June 1991
6
FIG. 2. Laguna Madre North of Port Mansfield
FIG. 1. South Land Cut
o it
5
4
1.
N~ t:;
i. , I_
~\'''.II~~W~!~I~\,'J'\\.a ~I~~,~ :'I 1" ~lli\' '1,(.tJ ,.. ~ "Pk/\ Jlty ~I ~I -200
-400
r
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i~I
I
,~. i~~ ~. .,
.~it
2 3 I4 5 6
7
"'-'it
'
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8
9
10
June 1991
FIG. 4. Laguna Madre South of Port Mansfield
11
l~
I'
\J
1
t
i,1
re•
12
13' 14
.
i!
2Or,--~---'----r---r---~--'----r---r--~---'--__r---r---~--~
60
~
,
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,
I
1200 11
2400
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•
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1200 13
,
, Observ~
1200 10
2400
June 1991
,
I
1200 11
2400
1200 12
I
2400
1200 13
June 1991
FIG. 5. Old causeway (Eastern)
FIG. 6. Old causeway (Mid East)
1.5rl-----,------r-----,------,------r-----,-----_r----_,
151r-----,------r----~----_,r_----~----,,-----r----_,
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2400 June 1991
FIG. 7. Old Causeway (Mid West)
1200 12
24'00
12'00 13
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Observed
Nautical Chart
Nautical Chart
1200 10
24'00
12'00 11
2400
1200 12
2400
-1.~';00
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1200 10
24'00
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11
June 1991
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24~lO June 1991
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0.2
-0.4
::;w~
10
11
12
13
14
15
-0.4
2
3
4
5
6
7
8
June 1991
FIG. 4. South Bay Tide Station.
9
10
11
12
13
14
15
1.5rl-----,------r-----,------r-----,------r-----~--__,
1.5rl-----,------~----.-----_.------r-----._----~----_,
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400
Observed , Nautical Shart 1200 2400 10
, 1200 11
I
2400
, 1200 12
I
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~
-0.5
- - Observed
1·~4oo
-.-.-.. Nautical hart 2400 1200 10
1200 11
2400
1200 12
2400
1200 13
1200 12
2400
1200 13
June 1991
June 1991
FIG. 2. Port Mansfield JeHles
FIG. 1. South Land Cut
1.5
1.5 ,
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-.-.-.. Nautical Chart
Nautical Chart 1 1400
1200 10
2400
1200 11
2400 June 1991
FIG. 3. Mouth of Arroyo Colorado
~
()
- - Observed
1200 12
2400
1200 13
-1
1400
1200 10
2400
t200 11
2400 June 199t
FIG 4. GIWW North of Arroyo Colorado
1.5rl-----,------r-----.------r------r-----,------r-----,
1.0
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,
, Observee
1200 10
2400
I
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1200 11
, 1200 12
I
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June 1991
June 1991
FIG. 5. Old Causeway (Eastern)
FIG. 6. Old causeway (Mid East) 1.5rl-----,------r-----,------r-----,-----,r-----~--__,
1.5 f i--r---,--..-------,r-----,-----,--,-~
1.0
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-1.0 I-
- - Observed Nautical Chari
-1·~';00
1200 10
2400
1200 11
24~0
1~ 12
June 1991
FIG. 7. Old causeway (Mid West)
~
• --'
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en
24~
-1.5 I
1200 13
2400
-.
_._._..
-
• '-'"
-.--
-
•
-
Nauiical Chart Observed
1200 10
I
2400
I
1200 11
2400 June 1991
FIG. 8. Old causeway (Western)
I
1200 12
2400
1200 13
1.5r'------,-------r-----~------_r------,_------r_----_,----~
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w
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1200 10
Observed
Observed
Naulical Chart
Nautical Chart
24'00
1200 11
24'00
1200 12
2;00
1200 13
-1 i;oo
1200 10
2400
12'00 11
24'00
June 1991
lSr'------r-----,------,------,------r------,------r-----,
-
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1200 10
24'00
1200 11
2400 June 1991
FIG. 11. SOuth Bay Pass
~
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-
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a:
-1·~4'oo
12'00 13
FIG. 10. Brownsville Ship Channel
1.srl-----,------r------r-----.------r-----,------r-----,
ul >
24'00
June 1991
FIG. 9. Port Isabel Channel
! 0"
1;100 12
1200 12
2400
1200 13
I
2400
I
1200 10
2400
1200 11
2400 June 1991
FIG. 12. Brazos Santiago Pass
,-
1200 12
2400
1200 13
4oo,r--'--~--~---r---r--'---~--r--'r-~--~---r--'---,
~, ~
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., '
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, 11
1'i/' 'i" , I
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-
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-,-,-..
Nautical Chart
·2ooL'~~~~~~L-~~~~~~~~~-L~~~~~~~~~~~~
2
3
4
1,000
9
,lJ
..
Nautical Chart
5
7
6
8
9
10
11
12
13
-1,000 , .
14
10
June 1991
11
12
13
14
June 1991
FIG. 1. South Land Cut
FIG. 2. Laguna Madre North of Port Mansfield 1,000 rl-..,...--"---r--'--~---r--..,...--"---r--,r-"""T---r--..,...~
4oorl--~--r-~r-~---r--~~r-~---.--~--r-~---r~
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200
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FIG. 3. Port Mansfield Channel 'l VJ
~
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1- /.\I
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Nautical Chart
·ISOLI~~~~~~~~~~~~~~~~~~-L~-L~-L~~~~___,~
-30kl~~~~~~~~~~6~-=7~~8~~9~-t~0~~I~I-L~1~2~7.13~~1~4~
2
3
4
5
6
June 1991
FIG. 5. Arroyo Colorado West of Languna Atascosa
1,500
500
~
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2
3
4
5
6
7 8 June 1991
9
FIG. 7. Laguna Madre North of Port Isabel
10
11
12
13
14
:'
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ii
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. : 1 :: ~
I,
1,000
1'1
J
Nautical Chart
Nautical Chart
1\ I , " " I" I,
10
11
12
13
14
Survey
Survey
~
9
2,000 r,-,--,.--,----,,.--_,--,.--.-,--,--r----,-......,---.-,
r-,
~
8
FIG. 6. Arroyo Colorado East of Laguna Atascosa
2,000 ---.---.---,--r----,,.-----.--,.--r--.--,--r----,----.---,
1,000
7
June 1991
'Ii
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FIG. 8. Brazos-Santiago Pass
8Oir---r---~--'----r---r--~--~--~r---~--r---T---'----r--.
60
2oolr--'--~---r---r--'---r-~r-~---r---r--'---r--'r--,
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if.
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9
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·40 Nautical Chan ·60~i~~~~~L-~~~~~~~~~~~~~~~~~~~~
.300LI~--L-~2~L-~3-"L-4~"-~5~~~6~L-~7~L-~8-"~9~"-~1~0-"-Ol~1-L-1~2~~1~3~-c1~4-' June 1991
June 1991
FIG. 9. Brownsville Ship Channel
---1 U\.
FIG. 10. South Bay Pass
SWIFf2D SIMULATIONS
Time Step Variation Simulation
Manning's n
=0.025 in navigation channels =0.075 in the vicinity of the old Queen Isabel Causeway =0.035 elswhere
Wind Stress
= 0.0015
Time Step
= 12 minutes
loO,,--'--~---r---.---r--.---'---.---r--'r--'--~---r---.--,
1.0 rl- - ' - - . - - - . - - . - - . - - - . - - , - - . - - - . - - . - - . - - - . - - . - - . - - ,
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Survey
Observed Naulical Chan (J)
(J)
a:
a:
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tu ::ii
w
w
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~
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w
--' w
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2
3
4
5
6
8 9 June 1991
7
11
10
12
13
14
-0.4
15
2
3
4
5
6
7
8
9
10
11
12
13
14
15
June 1991
FIG. 2. Port Mansfield Tide Station
FIG. 1. Rincon Del San Jose Tide Station
1.0
loT
Survey
0.8
Observed
~
J
-----
Survey
Nautical Chart (J)
~ 0.6 ~
w ::ii ~
a: ~
-'
•
w
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i ::U~AA!'n
f'
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-0.2
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2
3
4
5
6
7 8 9 June 1991
FIG. 3. Port Isabel Tide Station
10
11
12
13
14
15
-0.4 -
1
2
3
4
5
6
7 8 9 June 1991
FIG. 4. South Bay Tide Station.
10
11
12
13
14
15
1.5rl------r------r------r------r------r------r------r-----~
~
1.5rl-----,------r-----,------r-----,------r-----~--__,
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a:
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1200 10
2400
, 1200 11
I 2400
, 1200 12
I 2400
, 1200 13
~
- - Observed
1200 11
10
June 1991
2400
1200 12
2400
1200 13
1200 12
2400
1200 13
June 1991
FIG. 1. South Land Cut
FIG. 2. Port Mansfield Jetties
1.5
1.5
1.0
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1200 10
2400
---
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-.-.-.- Nautical Chart
Nau1ical Chari -1.5 2400
1200 11
2400 June 1991
'-I ~
r----.
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FIG. 3. Mouth of Arroyo Colorado
1200 12
2400
1200 13
-1'~400
1200 10
2400
1200 11
2400 June 1991
FIG 4. GIWW North of Arroyo Colorado
1.5r'----~------._----,_----~------r_----,_----_r----_,
1.Qf-
-
0.5
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t
I
1200 11
.. _\
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-1.5 2400
1200 13
•
,
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2400
1200 10
June 1991
,
I 2400
1200 11
1200 12
I 2400
1200 13
June 1991
FIG. 6. Old causeway (Mid East)
FIG. 5. Old Causeway (Eastern)
1.5,r------,-----.------,------.------.------r----_.r---,
1.5,r------r------r----_.r------r------r------r----_.r-----,
1.0
~
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-1.0~
Nautical Chart
1~;00
1200 10
2doo
1200 11
24~0 June 1991
FIG. 7. Old Causeway (Mid West)
1200 12
2400
1200 13
-1~;00
........,I/
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•
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1200 10
..L
I
2400
'!=
2400
1200 11
June 1991
FIG.8. Old Causeway (Western)
.l.
1200 12
2400
1200 13
1.5r'-----,------~----_r----_,------r_----._----~----~
~
~
~
~ ~
1.5,r_----~----_r----~------r_----~----_r----~----_,
~
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a:
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Observed
Nautical Chart
Nautical Chart
1200 10
24'00
12'00 11
24'00
2~
1200 12
-1~;00
1200 13
1200 10
2400
1200 11
2400
June 1991
~
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FIG. 2. Laguna Madre North of Port Mansfield
FIG. 1. South Land Cut 400rl--~--_,----r_--r_--~--,_--_r--_r--_r--~--_,--_.r_--r___,
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APPENDIXB LIST OF FILES FOR DELIVERY
INDEX
This file
For all coverages with elevation data the item SPOT represents the elevation (depth) in meters, while the item HOLD represents the elevation (aepth) in feet. All coverages are in UTM coordinates with NAD27.
USGS 1:100,000 scale digital line graphs (DLG) The DLG's were used to develop the boundaries of the mode grids. baffin_b.hys.eOO.Z brownsville.hys.eOO.Z cchristi.hys.eOO.Z harlingen.hys.eOO.Z p_mansfld.hys.eOO.z laguna_hys.eOO.Z
Baffin Bay DLG Brownsville DLG Corpus Christi DLG Harlingen DLG Port Mansfield DLG Combination of DLG's which cover the Laguna Madre
USGS 1:250,000 scale Digital Elevation Model (DEM) The DEM's could be used to add elevation points on land. demread dugdem.txt brownsville-w.Z corpus_christi-w.Z port_isabel-w.Z
Simple shell script to format DEM data for use in ARC/INFO. Description of demread Brownsville DEM Corpus Christi DEM Port Isabel DEM
Coverages derived from the NOAA/NOS Nautical Charts. laguna_c.eOO.Z laguna_con.eOO.z laguna_d.eOO.Z laguna_sd.eOO.Z
Channels Contour lines Depth points Supplemental depth points adde by hand
Coverages, grids, amls, etc. used to derive the model grids for the lower Laguna Madre. The grid used in the model was rotated 13 degree in order to reduce the size of the grid needed to represent the estuary. All coverages needed to create the grids are listed below. rl195grd.aml rllcgrd.aml 1195grd.aml llcgrd.aml 1120095_grd.eOO.Z 11200c_grd.eOO.Z 1195sup_d.eOO.Z Ilaguna_c.eOO.Z Ilaguna_d.eOO.Z Ilaguna_i.eOO.Z Ilaguna_sd.eOO.Z Ilm95 d.eOO.Z Ilm95 land.eOO.Z lltin:::clip. eOO. Z 11aguna_Iand.eOO.Z
AML used to generate the rotated 200 meter grid from the hydrographic survey data (HSD) AML used to generate the rotated 200 meter grid from the nautical chart data (NCD) AML used to generate an unrotated grid from the HSD AML used to generate an unrotated grid from the NCD Unrotated 200 meter grid from HSD Unrotated 200 meter grid from NCD HSD supplemental depth coverage NCD channel coverage NCD depth coverage NCD island coverage NCD supplemental depth coverage HSD depth coverage HSD land boundary outline Clip coverage used to create tins NCD land boundary outline
Miscellaneous Coverages Im95xy.eOO.Z stations.eOO.Z tx95.eOO.Z
Coverage of the HSD Coverage with locations of tide, wind, velocity, water quality, etc. stations Coverage of the mesh points in the TXBLEND model
Coverages, grids, amls, etc. used to derive the model grids for the upper Laguna Madre. All coverages needed to create the grids are listed below. ulgrid.aml u1200_g.eOO.Z u1400_g.eOO.Z ulaguna_c2.eOO.Z ulaguna_d.eOO.Z ulaguna_i2.eOO.Z ulaguna_sd.eOO.Z ulland.eOO.Z uloutnc.eOO.Z ultin.eOO.Z ultin_clip.eOO.Z
AML used to create the 200 meter grid (NCD) for the upper Laguna Madre 200 meter grid (NCD) 400 meter grid (NCD) Channel coverage Depth point coverage Island coverage Supplemental depth points Outline coverage Outline coverage TIN of the upper Laguna Madre Clip coverage used to create the TIN
Upper Laguna Madre TIN based on HSD ulrn95tin.aml ulrn9S d.eOO.Z ulrn9S-tin.eOO.Z
AML used to create the TIN HSD depth point coverage TIN created from HSD
1
SIMULA TION OF THE LOWER LAGUNA MADRE ESTUARY WITH SWIFT2D
By Karl McArthur
U.S. GEOLOGICAL SURVEY
OCTOBER 9, 1996
TABLE OF CONTENTS
Page TABLE OF CONTENTS. ............... ........... ........... ........... ....... ........... ............... .....
ii
LIST OF FIGURES ...............................................................................................
iii
LIST OF TABLES ....... ................. ........... ................. ........... ......... ........ ....... ..........
IV
OVERVIEW..........................................................................................................
1
BATHY~TRY
AND GEO~TRY ....................................................................
5
SIMULATION RESULTS.............................................................................. .......
8
APPENDIX A: PLOTS OF RESULTS .................................................................
12
Calibrated Simulation..................................................................................
13
Velocity Vector Plots for the Calibrated Model with the Hydrographic Survey Data..........................................................................
22
Velocity Vector Plots for the Calibrated Model with the Nautical Chari Data ....................................................................................
37
Manning's n Variation Simulation ...............................................................
52
Wind Stress Variation 1 Simulation.............................................................
60
Wind Stress Variation 2 Simulation.............................................................
68
Time Step Variation Simulation ........................................... ;......................
76
APPENDIX B: LIST OF Fll..ES FOR DELIVERy...............................................
84
ii
LIST OF FIGURES
Page 1.
Locations of Tide Stations in the Lower Laguna Madre .................................. .
2
2.
Locations of Velocity Station in the Lower Laguna Madre .............................. .
3
3.
Locations of Flow Cross Sections in the Lower Laguna Madre ....................... .
4
4.
200 Meter Grid from Nautical Chan Data ....................................................... .
6
5.
200 Meter Grid from Hydrographic Survey Data ............................................ .
7
6.
Location of Grid Cells Which Dried During the Simulation (Nautical Chan Grid) ...................................................................................... .
7.
11
Location of Grid Cells Which Dried During the Simulation (Hydrographic Survey Data Grid) ................................................................... .
12
iii
LIST OF TABLES
Page L
Geometric Characteristics of the Nautical Chart and Hydrographic Survey Grids ...................................................................................................
2.
Root Mean Squared Errors (meters) between Simulated and Observed Water Levels................ ...................................................................................
3.
8
10
Root Mean Squared Errors (square meters) between Simulated and Observed Water Levels....................................................................................
10
I
-Ii
iv
OVERVIEW
The lower Laguna Madre Estuary from the south end of the Land Cut to South Bay was simulated with the SWIFT2D model. The lower half of the Laguna Madre has two openings to the Gulf of Mexico. Pon Mansfield Channel and the Brazos-Santiago Pass at Port Isabel. The lower Laguna is connected to the upper Laguna Madre by the Gulf Intracoastal Waterway (GIWW) through the Land Cut. The most significant source of fresh-water inflow into the estuary is the Arroyo Colorado, which flows into the estuary between Pon Mansfield and Pon Isabel. The SWIFT2D simulations of the estuary were performed for the month of June, 1991, which corresponded to the June 10 through June 14, 1991 intensive inflow survey performed by the Texas Water Development Board (TWDB). Simulations were performed for water levels, velocities, and circulation patterns (hydrodynamics only). Salinity was not considered in the simulations. Inflows from the Arroyo Colorado were also not considered. 1bree tide signals were used to drive the model at the South Land Cut, Pon Mansfield Channel, and Brazos-Santiago Pass. The driving tides at the South Land Cut were provided by the tide station at El Toro Island. Tide records were available at Port Mansfield and Port Isabel, however, these stations were internal to the model.
In order to provide an external (Gulf of Mexico) driving tide, the tide signal from the Bob Hall Pier tide stations was used. The Bob Hall tidal signal was applied on the Gulf side of Padre Island at the Port Mansfield Channel and Brazos-Santiago Pass. The Bob Hall Pier tide station is located just south of Corpus Christi on the Gulf side of Padre Island. The Bob Hall tide was compared to the tidal signal at the Port Mansfield and Port Isabel stations to determine whether a phase shift would be required. The three tide signals were determined to be in phase, therefore, the unaltered Bob Hall tide was used to drive the model at both locations. The simulation results were compared to observed data at four tide stations and twelve velocity stations. These stations are shown in Figures 1 and 2 respectively. Results for flow were also output at the ten cross sections shown in Figure 3.
EXPLANATION ....
Tide Gage
Port Mansfietd
o
5
10
I
o
5
10
15 MILES
I
15 Kl~OMeTERs
Figure 1. Locations of Tide Stations in the Lower Laguna Madre
2
EXPLANATION A
Velocity Station
Port Mansfield Jetties
o
5
10
1SMIL.ES
j I
o
5
10
15 KlLOMElERS
:::::-"j~~OI~cd causeway
Brazos-Santiago Pass til Bay Pass
Figure 2. Locations of Velocity Stations in the Lower Laguna Madre
3
Observed tide data for the period of simulation was obtained from the Texas Coastal and Ocean Observation Network (TCOON) through the Conrad Blucher Institute. Observed velocities were obtained from the TWDB intensive inflow survey. The tidal datums were referenced to the mean tide level observed at each station.
BATHYMETRY AND GEOMETRY
Two sources were used to generate the bathymetry for the SWIFr2D model grid. The ftrst set of data was derived from the three, 1:40,000 scale NOAAINOS nautical charts which cover the lower Laguna Madre. The three maps are titled as follows: 1. Texas Intracoastal Waterway, Laguna Madre: Middle Ground to Chubby Island; 2. Texas Intracoastal Waterway, Laguna Madre: Chubby Island to Stover Point Including the Arroyo Colorado; 3. Texas Intracoastal Waterway, Laguna Madre: Stover Point to Brownsville Including the Brazos Santiago Pass. The second set of data consisted of the recent hydrographic survey data for the Laguna Madre obtained from the U.S. Army Corps of Engineers, Waterways Experiment Station. USGS 1: 100,000 scale digital line graphs were used to form the boundary of the estuary. The ARCIINFO geographic information system was used to process the bathymetry data and create the required information for the SWIFT2D model grids. Separate grids were created for the nautical chart data and the hydrographic survey data. The nautical chart grid was derived from 1080 points digitized from the charts, while the hydrographic survey grid was derived from 28,059 points. The hydrographic survey data obviously provides a more extensive set of points for the deftnition of bathymetry. Both grids were rotated 13 degrees clockwise to reduce the extent of the grid required to defme the study area. The resulting grids were 125 cells wide by 505 cells tall. The grid size used was 200 meters. The specifics of the two grids are compare in Table 1.
5
o
5
10
15
20 MILES
j !
o
5
10
15
20 KlLOMElEFIS
Figure 4. 200 Meter Grid from Nautical Chart Data 6
o
10
5
I
o
5
10
15
15
20 MILES
I
20 KI~OME'lCR8
Figure 5. 200 Meter Grid from Hydrographic Survey Data 7
Table 1. Geometric Characteristics of the Nautical Chart and Hydrographic Survey Grids Nautical
Hydrographic
Chan Grid
Survey Grid
26729
19439
Minimum cell depth (m)
0.1
0.1
Maximum cell depth (m)
14.5
14.3
Average cell depth (m)
1.35
1.65
Total area of cells with depth below MWL (lan2 )
1,069
777.6
1.44x:109
1.28x:109
Characteristic Number of cells with depth below MWL
Total volume below mean water level (m3 )
-I The nautical chart grid has a larger area of shallow depth along the east side of the estuary than the hydrographic survey grid. These areas are slightly above mean water level (MWL) in the hydrographic survey grid.
SIMULATION RESULTS
The SWIFT2D model was calibrated to the data measured during the 1991 intensive inflow survey performed by the TWOB. Several problems remain in the final model. The primary areas of difficulty are in the vicinity of the channels between the Laguna Madre and the Gulf of Mexico. Instabilities in the model solution were observed in the vicinity of the Port Mansfield Jetties in the sensitivity analysis. The model also was unable to accurately simulate the magnitude of the tidal signal at the Port Isabel and South Bay tide stations. A majority of the inflow from the Brazos-Santiago Pass appears flow northward into the estuary instead of into the Laguna Madre Channel and South Bay Pass. The calibration for the lower Laguna Madre could be improved with additional work on the finite element grid and calibration parameters.
8
The roughly calibrated SWIFr2D model produced fairly good matches between simulated and observed water levels at the Rincon del San Jose and Pon Mansfield stations. Results at the Pon Isabel and South Bay stations were not as good. Simulated water levels at these sites matched in phase, however, were smaller in amplitude. The fit could probably be improved by adjustments to the model grids. Additional simulations were performed to test the robustness of the model. The Manning's n values for the calibrated model were 0.025 in channels. 0.075 in the vicinity of the old Queen Isabel Causeway, and 0.035 elsewhere. A sensitivity simulation was performed with a constant n value of 0.030. Sensitivity runs were also performed for wind stress coefficients of 0.0001 and 0.0026 in addition to the calibration value of 0.0015. The calibrated model used a time step of 6 minutes. A time step of 12 minutes was used in a sensitivity run. The larger time step created instabilities in. the vicinity of the Pon Mansfield jetties in the hydrographic survey model. Complete results of the simulations are shown in the section at the end of this repon. Tables 2 and 3 show the root mean square errors between simulated and observed values for both models. Figures 6 and 7 show the extent of grid cells that dried at some point in the simulation. The hydrographic survey grid produced a substantially larger number of dry cells. The difference was a result of the shallower bathymetry along the east side of the estuary in the hydrographic survey grid
9
Table 2. Root Mean Squared Errors (meters) between Simulated and Observed Water Levels Constant n-value
Calibrated
No Wind Stress
High Wind Stress
12 Minute Time Step
Water Level Stations
NC
HS
NC
HS
NC
HS
NC
HS
NC
HS
Rincon Del San Jose
0.260
0.255
0.264
0.256
0.242
0.241
0.279
0.269
0.262
0.257
Port Mansfield
0.098
0.098
0.099
0.099
0.104
0.102
0.106
0.120
0.098
0.214
Port Isabel
0.146
0.142
0.144
0.135
0.129
0.133
0.158
0.148
0.144
0.138
South Bay
0.116
0.107
0.118
0.177
0.113
0.107
0.121
0.111
0.137
0.127
=== -
-
Table 3. Root Mean Squared Errors (square meters) between Simulated and Observed Water Levels Constant n-value
Calibrated
-
o
No Wind Stress
High Wind Stress
12 Min. Time Step
Velocity Stations
NC
HS
NC
HS
NC
HS
NC
HS
NC
HS
South Land Cut
0.226
0.251
0.244
0.261
0.204
0.244
0.248
0.259
0.212
0.244
Port Mansfield Jetties
0.698
0.731
0.772
0.768
0.691
0.685
0.692
0.725
0.783
0.809
Mouth of Arroyo Colorado
0.096
0.105
0.096
0.107
0.098
0.102
0.094
0.107
0.096
0.102
GlWW North of Arroyo Colorado
0.151
0.137
0.153
0.137
0.162
0.154
0.144
0.132
0.147
0.135
Old Causeway (Eastern)
0.208
0.198
0.208
0.194
0.192
0.191
0.222
0.204
0.257
0.233
Old Causeway ( Mid East)
0.175
0.143
0.191
0.156
0.161
0.134
0.186
0.149
0.231
0.198
Old Causeway (Mid West)
0.315
0.327
0.294
0.342
0.315
0.326
0.317
0.329
0.361
0.417
Old Causeway (Far West)
0.202
0.172
0.183
0.182
0.202
0.172
0.203
0.174
0.217
0.234
Port Isabel Channel
0.193
0.190
0.191
0.193
0.190
0.185
0.196
0.194
0.273
0.246
BrownsviUe Ship Channel
0.259
0.249
0.252
0.247
0.252
0.247
0.263
0.251
0.281
0.264
South Bay Pass
0.289
0.261
0.288
0.261
0.283
0.255
0.291
0.249
0.293
0.262
_
....
-.--
:
-
5
10
i 10
15MI~S
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15 KI~OME1ERS
Figure 6. Location of Grid Cells 'Mlich Dried During the Simulation (Nautical Chart Grid). 11
5
10
I 10
15 MI~eS
I
151-
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0 -0.2
-0.4'
-
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2
3
4
5
6
8 9 June 1991
7
FIG. 3. Port Isabel Tide Station
10
11
12
13
14
15
-0.4
2
3
4
5
6
8 9 June 1991
7
FIG. 4. South Bay Tide Station.
10
11
12
13
14
15
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FIG. 7. Old causeway (Mid West)
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,
-
NaullCai Chari
1:!Oo 10
..........
1200 11
24'00 June 1991
FIG. 8. Old Causeway (Western)
1200 12
2400
1200 13
I.Sri------,_------r-----~------_r------,_----_,r_----_r----__,
l.Srl----_,------r-----~----_r----_,r_----r_----,_----~
i
i
g
g
~
~
w
w
>
>
~
!
~ :::> Ul
Ul
Suntey
w a:
-1~400
Survey
~
ObsetVed
Observed
Nautical Chart
Nautical Chart
12Do 10
2400
1200 11
2400
12Do 12
2400
-1~4'oo
12Do 13
12Do 10
2400
1200 11
24'00
1200 12
2400
1200 13
June 1991
June 1991
FIG. 10. Brownsville Ship Channel
FIG. 9. Port Isabel Channel
1.S ir----,.------.---,-----.----r--:----,-~--
l.Srl-----,------r-----~----_r-----,r-----~-----r----,
1.0
i
~
g ~
... ."...,
osl-
J~~!'''
t-"
o l'''.!
~,. . ; \,..
~
:&.
.~
~l-~,
' ' ...
.... -
{~" I ,~,~7'
.....1
'.'-0,;-.
wi ,~ ~';':1\-\"\
~\-., i _ \j.......'.1 .\_.1 •
. -'=/",
-\.... /;-" \ ~..."".i
-
~ ,.'
•
:::> -O.SI-
-
~
-
~
>
~
w
a:
Simulated
_-_._..
-1~4'oo
•
-I
Nautical ChaTt Observed
12Do 10
24'00
1200 11
24'00 June 1991
FIG. 11. South Bay Pass
---~
~
gw Ul
Ul
-1.0 I-
i
12Do 12
2400
12Do 13
-1~4'oo
1200 10
2400
1200 11
2400 June 1991
FIG. 12. Brazos Santiago Pass
1200 12
24~
1200 13
~~
~
o~
...
...J
~ I(\\J .......:\., , V; .. \J'ilA'-v!"Y; iii",",,"",
f
r .'n\ . " \i.
'"
,
I.,
~
Ii
,I
\
II
II
• Ii i!!j
11
,I
l"1·,..7 , i
I,
~ I;J'~'
I
II
J
0
·100
~'. ~fb 'I\\J
to
'i
" i 'I !J:
2001-'
iii 100 M
j
f.'\'i!"\ J. hJ'" "''';;"",\,,;\..
II
..
~/~~4Y
'I
'1-
9
10
~
~
Survey Naullcal Chart
1.000
~
','0i ;
....i
~
5OO~ i l. ~
I
i.
~
:'0 1,,11 .j ~
~
•
Ii
1.500
it
0
----. Survey NaulicaJ CharI
·200
II
2
3
4
5
678
11
12
13
14
3
2
5
4
6
June 1991
7
8
9
10
11
12
13
14
June 1991
FIG. 2. Laguna Madre North of Port Mansfield
FIG. 1. South Land Cut
800
400
----- Survey
200
I! . "i\ l! ,\l
600 I- ,
~ ~ ,~
400~~~ iii
v
V
it o Survey
.600
t
-0
3
",
4
5
~
1 6
7 8 June 1991
FIG. 3. Port Mansfield Channel
9
10
11
12
13
14
·400
.~ ~,I Ii. I!.. fi "
,..
2
3
I,
~
,
~ ,~'\ rfl mi'l NaulJcal Chari
~P.I.!\J Iu ~ •
l' ~~ !~~! HIlt), \tr ~'~~Vli11 "I ~ i 1m II JI ,~ ~. ~1'
·200 I-
Nautical CharI
2
--
~ f:)I~
-.-.-.~
'; ·
I
I
..
~
U" '.
i,I
•
i
I
,
~~~~~~'99~'lII01'11~I'~122~'1~3t'14 4
5
6 June 78 1991
FIG. 4. laguna Madre South of Port Mansfield
20r,---r---r---r---r---r---r---r---r---r---r---r--.---.---,
6Orl-,--r---r-..,...~.---,r---r-..,...-..---,--r-.--r--,
~
401-
4. '\~~ , !II',.
~ e ~
• ~!
I'
~
w
~
-'
~
-'
c: ~
c: ~
~
~
-0.4 '
2
3
4
5
6
7
9 8 June 1991
10
11
12
13
14
-0.4
15
2
3
4
5
6
7
8
9
10
11
12
13
14
15
June 1991
FIG. 2. Port Mansfield Tide Station
FIG. 1. Rincon Del San Jose Tide Station
~O~
1.0
~
Survey
Survey Observed
0.+
Naulil (J)
(J)
c: ~
c: ~ w
~ ;::
:l;
;::
-' w
-'
w
>
~
> w
0.2
13
14
-'
f-
f-
~
0 ·0.2
-O.4l
2
3
4
5
6
7
9 8 June 1991
FIG. 3. Port Isabel Tide Station
C
l/ll
w
w
c(
~~
c:
c:
;:
tlt.J1J 11 \ n
LA f\ II
10
11
12
13
14
15
i
·0.4'
~-
2
3
4
5
6
7 8 9 June 1991
FIG. 4. South Bay Tide Station.
10
11
12
15
1.5rl----~------~-----r----_,------r-----,_----~----_,
1.5,r----~------r_----,-----_r----~------r_----,_--__.
~
iQ ~
~
~
8 ...J
8
>
W
~
!z ~ 5
...J
~
-os
:> 1/1 w
1/1 W
II:
II:
Survey
Observed -I
t
~400
Observed
,Nautical Shart.
1200 10
2400
1200 11
I
'
I
'
2400
1200 12
2400
1200 13
i
-I
t ~4OO
, Nautical Fhart, 1200 10
2400
1200 11
1.5rl----~------r_----,-----_r----~------r_----~--__,
~
0.51-
~
9~
9
w >
!z ... ....
-
5°·51-
1/1
~
!z...
!:; :> 1/1
w
S,mula,ed
-
-1.0 I- ---- Observed
Slmuiated
II:
Observed
Naullcal Chart
Naulical Chart
-1~4'oo
12fJo 10
2~
1200 11
2~ June 1991
FIG. 3. Mouth of Arroyo COlorado
-t...
1200 13
-
1.0 I-
V\.
2400
FIG. 2. pon Mansfield Jetties
15,r----~----_,-----,----_,r_----r-----._----~--_,
~
j
, I
1200 12
June 1991
June 1991
FIG. 1. South Land Cut
~
I
2400
12fJo 12
2400
12fJo 13
-1~~
12Do 10
2~
12Do 11
24'00 June 1991
FIG 4. GIWW Nonh of Arroyo Colorado
12Do 12
24'00
1200 13
1.5,r------r------r------r------r------r------.------r----~
15 [r-----,~--r---r--___.--"T"--__r--~-__..
1.01-·
101-
!
~ 0.51-
.....,.-.
!~;:
~w O~I >
f,;
!
.~,.~:::.:-
••
·0.51-
Ul
w
a:
.. •
,.-......
/.'--'''::.,.
r..\\'\
~
!
/,_.-..
".,.\
"-'-
,.! ' ' ...", '\. .~ - ~. .;-,~.-.
,.;-......,
,.
'\
~::::-~~ .
... .... .........
~
-
•
o~
,.'.'.-. __ '.....
l;
~
\"
z? :::l
a:
Survey
·101-
•
I Observe~ 1200 2400 10
NaullCaI Chari I
2400
1200 11
1200 12
2400
.l
1200 13
•
tl
Obse",~
I
2400
1200 10
I
I
1200 11
2400
1.5,r----~------r_----~----._-----r----_,------.---__..
!
~
~
i"';:·::.':;,.....
~
l,'
w
,I
>
~
....I
.,. ..,~
.1/ .t""
Ul
Ul
a:
a:
w
w
-
1200 10
24~
..... _.. •
•
-.-..
Naullcal CharI
Observed
• 1200 11
24~O June 1991
FIG. 7. Old Causeway (Mid West)
1200 12
24~
1200 13
.lt4~
Observed
1200 10
.1""'-=-·~
..,..-., •
~._,
"":'• !_'
Survey
Naullcal CharI
'1.~.:oo
.,,-.....
!/...........!,.....It \''',11 .',1 >P', .....,J' . ' .../ I .....; ....,
rJ.-\.
:::l
:::l
'-1\
1200 13
2400
FIG. 6. Old causeway (Mid East)
!
ZJ-j
1200 12
June 1991
1.5 rJ------.------r------.------r------.------r------.-----,
~
...,
w
FIG. 5. Old causeway (Eastern)
~
:\,
''=''_''/ ......._.'
June 1991
W
,,-,_.
(,,---~\
•~. . . _. . . . i ..... _.....
• \,.
t! . . . I . "'-' .
Nautical Chari
.li400 t
>
..... -.-....
!----i.,~
",:-__ ~l
0-,.
/"--i:
,,-'-'''''
-~~\
Ul
Survey
·1.0 I-
-
2;00
1200 11
2400 June 1991
FIG. 8. Old Causeway (Western)
1200 12
l
"
1. 5 r'-----,------r------r-----,------.-----,------r-----,
~
15,r-----,------,-----,------r-----,------,-----,-----,
~
~
~
g
gw
w
>
>
!z ~
!z
~
~
Ul
Ul
Sutvll)'
~
ObS8l\led
Observed
Nautical Chan
Nau',cal Chan
1~
-114'00
Survey
~
1~
2400
10
1~
2400
11
2~
1~
12
1~
-11.:00
13
2400
10
1~
June 1991
~
g ~
~
~
o \..I
:'fr~.,.,,~
't-"
/' 'r,,-'
-r'
S·.4..,. . . .
\" ' . ,.,. , 'i.' \..-'.'
-
~ ., J ......-.. ... , 1::r:~4 '-~
\,
..•
\"'~ ". ",','. .....1
-0.51-
r .... ,.
1;'-'> ..
,-', ,'; ,.,;
\.¥\."
•
-
-
1.5r'------,------;,------r------,------;.------r------,------,
~
i /
,,I , I
8... !z
~
I
j
w
>
t';, " ........
,../7',
~
..',
I
~)
!,
11
'I
",
-'/
Ul
~
S,mula'ed
-1.0 ~ ______ . Nau1Jcal Chait •
1
-1 ;00
Observed
1~
2~
10
1200 11
2.wo
1~ 12
2~
1~ 13
11.wo
1~ 10
24'00
1200 11
.lJne 1991
FIG. 11. South Bay Pass ~
1)'\
1200 13
-
~
",..
w
a:
... . ,.~,
2400
12
FIG. 10. Brownsville Ship Channel
1.5rl-----,------r-----,------r-----,~----r-----,-----,
~ 0.51-
1~
June 1991
FIG. 9. Port Isabel Channel
1.0 I-
24'00
11
24'00
12 June '991
FIG. 12. Brazos Santiago Pass
1~
24~
1200 13
,I
300
~
_
~ j~"j . .
r lI'l\f\\J\, ~~ v\.""~1~",-;i,i1\ 11\A J\ i~~J\,~'\1l' : ,-.' .
2001-,
~~
"
h
A'
I
j
'''.Ii
. '\
l"oi ,(-'
o~
0
l ~I
·100
.200
IrJ
\
''\,j\,.
uV
I'
f""'J:,}
'I ~I
5 /Ij'l'i'Vi ~I,;t: • !~f"~
",I V
1.500
Survey Nautical Chart
I
I
I
it
A
\,,1..1/\'\~¥. \" i\.
1'11\
100
j
\I
;1
iii 01
~
...~
V
Survey
r
~
NaulicaJ Chart 2
3
4
5
6
7
8 June 1991
9
10
11
12
13
FIG. 1. South Land Cut
4 ~ r "
~ A
-
..· II, I\
~
II
.I
200
·
V
t _:_,_u. Nau~caJ C~~I. Survey
2
3
4
5
.
9
10
11
12
13
14
6
7
8 June 1991
400
to
11
12
13
~il
'jl~, f!
' . 'I
I
I,
I,
" '!
Iii
...
I.
'IIj
I
r~&.r'~\J,U fJ,
>i i i " , I 1 I i' iii
J.I~~., •, .
'-.
"I
,", i ~
,
t."
"
" " "
,
~ ~ 'j~
I
1\
I 11 ",iit
O~ ~\(.tJ ~~ l~lntl V'n,f\~IUj 1ft 1~ VIJ I~~ I - n'~ iA !j
14
~1~I~iI
_._._.- Nautical Chari
'li I
" !\!
• .
.T.f.'. . . 1 9
----- Survey
~ ~t, II; I~
~ I I · \1 Ii d ~ ~
•
FIG. 3. Port ManSfield Channel "-J
!
600 I-I I,,j ,. j!
~ r~
~
7 8 June 1991
6
800
200l1,
,600
5
4
FIG. 2. Laguna Madre North of Port Mansfield
400
~
3
2
14
Y!i
'-., •
'-#jl
.
,
,I
2 3 4 5 6 7 8 9 1 0 1 1 • 12 . 13 June 1991
FIG. 4. Laguna Madre South of Port Mansfield
U I
14
20,r---r-~r-~r-~r-~r-~r-~r--.r-~r--.r--.r--.r-~r--'
60
~
l
I
I
:.~_
~ ~
0
...~
o•
it
J I~ 'l•I!~ ,Ih,~'~'l ~ ~ll, \ II' "."
il~
l
ji~'\\ "~~ll'Vl"l~I"~IJ!Ii \1 . r .'i'll'"
.20 .40
-10
P.'.,
(,
.~
•
•
•1\"
~'\
"
•
I~
.
.,
i'~Jil,· dl~~I\~i 'I,' ,0 I1',1. I
"
I
.,00[
-2O~'~~~~=-L-~~~~~~~~~~~~~~~~~~~~
,.
3
2
5
4
6
June 1991
_._.-..
I
Nauucal Chart
Nautical Chart
4
r
,J.
"
V \-;I Y." ,I ~ ~
'"
[I
~
2
3
4
5
6
7 8 .Alne 199'
9
FIG. 7. Laguna Madre Nonh of pon Isabel
10
11
12
13
'I
•
A
"
,\
"
I
'0
11
12
13
14
,\I,
'~
1 ,
f
14
~
~
~
:'
,1 I~
d'. "
f\ ~J ',. !'.
'~,
. "
f\
r'·l '.J 1 It II
II
~
...~
·,OOOL'~~-=~~~~~~~L-~~=-~~~~-L~-L~~~~~~~~
.
9
Survey
I - ,"V ."~ N 'uN \/\ ~ A11 I
8
2,000 ir--,--r--.---r--.---r---,--r---r---r--..--,,.......~-..,
Survey
'"
7
FIG. 6. Arroyo Colorado East of Laguna Atascosa
1,500 r,-..,---r--.---..--......---.--,--..,---r--.---,.--,..---,--,
r
I
June 1991
FIG. 5. Arroyo Colorado West of Languna Atascosa
-500 I-
I
Naulical Chan
Nautical Chart
I
'I I... -
1
SUlvey
"ooot- I
;'\
t· I' • " '!';k,!, IJ.!'I' 'i fJ fWi " , """ I ~ , '. -:I /' I! ~! , ,,~' , ' ~ ~'I. ' i~ i· (!~ ! V' j I In I! I' !'I!,' ~ , ,, . ; .....' ~~~i j j ., Ii j. ' Ii' ! , i ~!' ij! rit! J II'. Iiit ,.! ,'!' " iii . ' .,.~ y ri W I~' ! .,,.,., ,
"•
~
v
~~"". /I./v. II'V l,1f !~i :j Ii
.'
".,.~IIJ
~ ~
-2,000 L'_--'-__--'---::---'-__--'--=---'-_~=-~::_L-:_~~~----'-c~--cc~-..J 2 3 4 5 6 7 8 9 10 11 12 13 14 June 1991
FIG. 8. Brazos-Santiago Pass
8Or,---r--~--T---r---r-~~~---r---r--~--~--r---r--,
2OOr,--'---r-~---'--T-~r-~---r--~-'---r--'---r--,
60 100
40
iii
iii
~
~
., 20
~
....I
i'I
~
0
0
....I
LL
LL
-20
-100
,
Survey
Survey
Nautical Chart
Naullcal Chart
-60~'--~~2~~3~L-4~L-5~L-6~L-7--~8~L-9~L-107-'L-1~1~~127-'~137-'--14-J
-200
t
2
3
4
5
~e1W1
FIG. 9. Brownsville Ship Channel
4~
FIG. 10. South Bay Pass
6
7 8 June 1W1
9
10
11
13
14
1.5 r,-----.------,------.------,------,-------,r-----r-----,
1.5ri-----r----~----_,r_----r_----r_----~----,_--~
~ ~ §w
~ ~
§ ~
>
iz ~ 5 Ul ll!
0
§5 -os
-0.5
Ul
~
Observed
t
-1
1400
.NaubcalGharl 1200 2400 10
Observed i i i 1200 2400 1200 11 12 ..\Jne 1991
i 2400
. 1200 13
i
1400
:;
-
~ 0.51-
~ of---~>=C: ~~,cC --
-0.5
~
§ ~
§5
-0.5
w
Simuialed
Simulaled
a:
-1.0 ~ --__ Observed
1200 10
2400
Observed Naulical Chari
1200 11
2~00 ..\Jne 1991
N
j
1200 13
~
Naubcal Chari
()\
.
2400
1.5ri-----,------r-----~-----r----__r----r-r_----~--__,
Ul
Ul
-1.~.:oo
1200 12
-
1.0 iii
a:
I .
2400 June 1991
1.5r'------r------r------r------r------r------r------r-----,
w
. NauucalEhart. 1200 2400 1200 10 11
FIG.2. pon Mansfield Jetties
FIG. 1. South Land Cut
iz ~ 5
t
-1
FIG. 3. Mouth of Arroyo Colorado
1200 12
2400
1200 13
-1 1
.:00
1200 10
2400
1200
2400
11 June 1991
FIG 4. GIWW Nonh of Arroyo Colorado
1200 12
2400
1200 13
Survey Observed
NaulocaJ Chari III
(/)
a:
a:
w
~
t;;
::;
::;
-'
w > w
w > w
a: ~
a: ~
-z
~ -'
0.4
-'
-'
~
~
-0.4'
2
3
4
5
6
7 8 9 June 1991
10
11
12
13
14
~0.4
15
2
3
4
5
6
7
8
9
10
11
12
13
14
15
June 1991
FIG. 1. Rincon Del San Jose Tide Station
FIG. 2. Port Mansfield Tide Station
1.0 ~
1.0
~
Survey Observed
~
----- Survey
Nautical Chan III
III
a: ~
a: ~
~ -'
~ -'
w ::;
~
w >
w > w
~
a: w >-
a: w >-
-'
...:>:
...:>:
0.2
0 ~0.2
-0.4'
2
3
4
5
6
7
8
June 1991
f0.
FIG. 3. Port Isabel Tide Station
9
10
11
12
13
14
15
~0.4
-
1
2
3
4
5
6
7
8
June 1991
FIG. 4. South Bay Tide Station.
9
10
11
12
13
14
15
1.5rl-----.-----.-----.r-----r-----~----,_----,_--__,
15f[------.------r------r-----,------,r-----,-----~------
101'-
10 I-
iii ~
~
()
~
0.5
~ >
,"
._.
0
U)
I
•
I ."t._~f
;!
-.....
-0.5
.
w
a:
.'......-
;. .--.. . .~~,.
\\ 11",
~.,
S
!"...........
~"'-
li""---"~\
j
,\
(". . -::~'\..
"\
~ 1 • _... ~.'I
\. •• \:--_,~
...._-'
.....-.
·
•
,--.
I'-"'-~
-
.
•
,Observe1
1200 10
~5
2400
,..---.
.r--"·:\ J'--::~'\' ~"-.J .ii'::.~~
~:
0 /'
. . .....
;,,.A . . ~.
_n~.
·0.5,
!~~~~
U)
w
Nautical Chart
.lo5t 2400
~
.
a:
Survey
-101-
~ 0.5l ;';::::...:. . ., 8
I 2400
0
1200 11
0
1200 12
I
2400
0
Survey
-
-101-
i
.1
Nautical Chart
1200 13
11
•
, Observ~
1200 10
2400
,
,
,
1200 12
2400
I
1200 11
2400
June 1991
1200 13
June 1991
FIG. 5. Old causeway (Eastern)
FIG. 6. Old causeway (Mid East)
1.5rl----~------r_--r-,-----~-----.r-----,_-----r----,
1.5rj----~----r-r_----~-----r-----.----_,------r---_,
10
~ 0.5
~
~ o Ii'/',.,~ l ' " l ti . ..... ~,_.-.-}' .~~._.-." _... .•..._ ' ~S •
9
i,~.r
w
>
>
~ ....
S U)
....
-0.5
-0.51-
U)
w
w
Survey
a:
a:
-10 I-
- - Observed Nautical Chart
-1'~4'oo
1200 10
2400
1200
2400
11 June 1991
()\
''-iJ
.
~
~
FIG. 7. Old Causeway (Mid West)
1200 12
2400
1200 13
-1~4'oo
-----..
•
..--'"",,_i Y #
-..
"
,-1
- ...
•
~ -
~
Naut,cal Chart Observed
1200 10
2400
1200 11
24'00 June 1991
FIG. 8. Old Causeway (Western)
1200 12
-~oO---12~ 13
1.5,r_-----.------_r------~----_,r_----_.------_r------~----~
1.5,1----~------r-----~----_r-----,------r_----T-----,
i
i
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fJ)
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w
II:
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Survey
w II:
ObselVed
Observed
Naubcal Chart
Nauucal Chart
1200 10
2~00
1200 11
2..'00
1200 12
2400
-1~4'oo
1200 13
1200 10
2400
1200 11
2400
June 1991
..
~ 0.51-
§w >
;
....
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~
ll-=
fol-.,.~:~,'--\.-.\ '. ,..,. ,\,. .... i \.....
.'
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-
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tz
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•
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-
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I'·
';
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,~
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8
-f'
..J
W
>
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,
I
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II: ~
Nautical CharI Observed
1200 10
2-Wo
1200 11
24'00 June 1991
-t...
i
fJ)
fJ)
w
~
1.5.r------~----_,------_r------~-----,r-----_r------~----~
-
•
o t-'\\ to..
1200 13
FIG. 10. Brownsville Ship Channel
1.5r'------r------r------r------r-----,r------r-----,r----,
i
24'00
June 1991
FIG. 9. Port Isabel Channel
1.0
1200 12
FIG. 11. South Bay Pass
1200 12
24'00
1200 13
.1~4'oo
1
1200 10
2400
1200 11
24 00 June 1991
FIG. 12. Brazos Santiago Pass
1200 12
" 2400
1200 13
\
200,r--'--~---r---r--'---~--r-~r--.---r---r--'---T--'
- [1"
f
~
is
~
-200
If"' -----.-'-"
.. ,..Ii
,\
"
;;~
ll'.'" Nv VV• '1",
...
.'00
·,.1
-
~/I . \1 '" ·
-200
~I F l ~ ·.J \, ~
~!
;11
NaulJcal Chart
-~~I~~~2~~3-L-4~~5~~6~~7-L~8~~9~~1~O~~1~1~~12~~13~~t~4~
_~LI~~~2~~~3~~4~L-~5~~6~L-~7~~8~L-9~~~10~~I~I-L-l~2~~13~~1~4-'
~nel~l
June
FIG. 1. South Land Cut
.~ ~
200
~
~r' I I' I ~ ~
-200
.00>
~~_~~.~
J [.
yl., \ J
Survey
V •.
-----
Survey
-.-.-.. Naullcal Chart
~ l00~
~ ~ld\~~~\llfRIb?;?'1#"~1A~\V!~\«\!if IIf\ II fl ~
i i
•
,"
,'I
,
__-r--~-'---.--r--T--'--'
-100 I-
\ . \I ; " i § _.
f. .• , ' A ,./11
";, \
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.',
Iv
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V
v.
ti
l
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V
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~
i
I
i
~
Nauhcal Chari
-600LI---L-2--~3~~4~~5~~6~~7~~8~~9~-1~O-L-l-1-L-l~2-L-l~3-L-l-4~
June
FIG. 3. Port Mansfield Channel
f\"-~
~,r--T--'---r--r--~-.
2 _
0
~ ...J LL
1~1
FIG. 2. Laguna Madre North of Port Mansfield
400rl--'---r--'---r--'---r--'---r--'---r--.--~--'-~
~
y
.,
•
'I!
-
Survey
tr.-Asu
Ii
100
.,
~"iJ
LJ
~
il
\l'~:J\IN,.' 'iV,j i ~ .W/! /11 .... ',,.:11".;'
if.;
-100
\
iV
0
I ~,A~ 'lM
j
,..1./1 .,...• t\..~. I! ~ ~~ tII{....." . ' '~ rv ~ --0'..1 \,.,.:'''I''~
100 I-
2OOrl--'---r--'---r--'---r--'---r--'---r--.---r--~-,
1~1
-2001
-----1-..-_~_
2
3
4
5
6
7 8 June 1991
9
10
FIG. 4. Laguna Madre South of Port Mansfield
11
12
13
14
l ' ,,,,: ' ,,,,,
'~
.
30
• II,1 II I I ~ U
4
I
~ n. "" ," ","\~ , " i.td,t!, (J ~ f, ,I d :l, III ifl~I \f!~i \!1 W'~1 1M ~r ~'i 1\ J v1.I 11il\UI\i if!.;
,~ •
2
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II
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l ,.Cll'i' i"! "
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,
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1 ,~;
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",
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2
i \! .,
i
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f'
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lin i'/ III
,400 1-'11
\' 'I
h\-n· l ',. -J '. ~I.' , '\ , '.'," 'i • I ,/
3
N
,.
~
\J \jVJV V 11II Id IJ1\ lJt. \,. II
4
5
6
,800L'~~~~L-~~~-L-=~~~L-=-~~_L-=~~~L-~~~-L~~~~
3
4
5
6
7
8 June 1991
9
FIG.7. Laguna Madre North of Port Isabel 1)'., f'I'.,
7
8
9
10
11
12
13
14
aulical Chart
1,000
~. ~
t, ;, rl ~"~1.r
~
1"'""
I"
~
1)'\{
~
u.
~' II
"\
> ~ a:
~
a: ~
i
~
-0.4'
2
3
4
5
6
9 7 8 June 1991
10
11
12
13
14
-0.4
15
FIG. 1. Rincon Del San Jose Tide Slation
Observed
5
6
9 7 8 June 1991
10
11
t
12
-----
w
::;~
2t; 0.4
--' UJ
0+
W
(\
f\
.AI \I Ul Ir~
1\
> UJ
0.2
13
14
15
Survey
II'.
--'
a:
a:
UJ l-
~
4
en a: ~
0.6
~ UJ ::E
~
3
1.0
~
Survey
Nautical Chart
>
2
FIG. 2. Port Mansfield Tide Station
1°f lQ
Nautical Chan
en
a:
UJ
i
0
·0.2
·0.4
2
3
4
5
6
9 7 8 June 1991
FIG. 3. Port Isabel Tide Station
6\ -!)
10
11
12
13
14
15
-0.4
2
3
4
5
6
9 7 8 June 1991
FIG. 4. South Bay Tide Station.
10
11
12
13
14
15
1.5ir_----~------_r------~----_,r_----~------_r------~----_,
1.5rl----~------r-----,-----_r----~------._----.---__,
~
~
g
~w
~
~
...J
~
>
~
!z... ~ UJ
:;)
UJ
w
a:
~
Survey Observed -
1S
t
2400
Observed
,NauIicaJGhart, 1200 10
2400
1200 11
i
,
i
,
2400
1200 12
2400
1200 13
i
.1.
t
i400
, Naulical Ehart! 1200 10
2400
1200 11
June .1991
I
,
I
,
2400
1200 12
2400
1200 13
June 1991
FIG. 1. South Land Cut
FIG. 2. Port Mansfield Jetlles
1.5 ir---r-----.------.----,r---r---,---~-__,
1.5.r------r-----,-----~------~----~------r_-----.----_,
LOr
~~
-
0.51-
~
~
~
~w
w
>
~
>
~ -0.5
:5
-0.5r
UJ
UJ
~ -10
~
w
Smulal8d
SImulated
a:
-
- _ Observed
-1.0
1:!OO 10
24'00
1200 11
24'00 June 1991
FIG. 3. Mouth of Arroyo Colorado
'-.\
C)
Observed
Naulical Chari
NaulicaJ Chart
-li.:oo
j
1:!OO 12
24'00
12'00 13
-li400
1~ 10
24~
1~
24~
11 June 1991
FIG 4. GIWW North of Arroyo Colorado
1200 12
2400
12'00 13
1.5,r------r------r------r------r------r------r------r-----,
-
1.0 fiJ)
1.0 IiJ)
~
-
~ 0.5 f-
t~:.=::.~. ,;:'~~~. . , j~:::::.:a.~.\ '':;:::'''.:.:\4 o t- ! ~ / ."\ j '" \~ W ~~-::.~. •• t:.:-.~:,.... .~.::=~.
§
J
~
~~
1.5 r[- - - , - - - - , - - - - - - - , - - - - - , - - - - - . , - - - - - , - - - - - . - - - - ,
-0.5~
W
II:
-1.0
Survey
f-
•
••
•
--i
~ ~
§ ~ ;:: :5
0.5
v;:.::::~'::~.
2400
1200 11
2400
1200 12
2400
-1.0
.\-~/
-
• ._ .
Survey
f-
Nauhcat Chart
•
-1~1
1200 13
,
ObseiVe~
1200 10
2400
,
I
2400
1200 11
1200 12
I
2400
1200 13
June 1991
FIG. 5. Old causeway (Eastern)
FIG.6. Old causeway (Mid East) 1.5 ,.------r---.----,.---,.---,-----,-----,.-----,
1.5 t '--,---.------r-----r---..--"J---,..-----~
~
iJ)
~ ~
~
§
§
r~
!z
~
(/)
(/)
W II:
II:
;
.
"
.II
w >
~
"
.. ~'
-
Survey
24'00
i
-.. ~- , .~ ~~
-t:
\,/1
('
•
•
I
\~
....._"/
.,., - _~
._,_ .~r
.....-"
Ii
_.
....,
Naulical Chart
•
Nautical Char'
12110 10
-.
•
w
~4'oo
k
--'
--' ::J
1
.~~.
I
~,-.,.~.,
- - Observed
1200 11
24~0 June 1991
FIG. 7. Old Causeway (Mid West) ~
!,---'=~\
•
June 1991
~
,.-.-',
~)
.~~,
•
~
, Observe~
1200 10
I
~~\
}
ii·':.-0.5
Nautical Chan
•
.~~
O'
,,::::'.::~,
(/)
.oj
-lit400
.r;-:':,.,
·1.5
1200 12
2400
12110 13
Observed
I
2400
I
!
1200 10
2400
1200 11
2400 June 1991
FIG. 8. Old causeway (Western)
1200 12
2400
1200 13
1.5,,------,------r----~r_----~-----r----_,------~--__,
1.5 ,r -----,------,------,------r-----,------,------,-----,
~
!
8....
8....
iii
~
~
w
~
>
!z
~
~
VI
::J VI
SuNey
~
ObS8fVed
Observed
Naolica, Chan
Naulica, Chart
1~
-11.:00
Survey
~
1~
2400
10
1~
2.:00
11
2400
12
1~
1~
-11:00
13
2400
10
1~
2400
11
FIG.9. Port Isabel Channel
1200 13
FIG.l0. Brownsville Ship Channel
1.5 r,-------,-------.----~----___,r_--r---_.___---.---__,
1.5rl-----,------,------,-----,,----~----_,------.-----,
-
10 I-
~
8~
•~
!z • >....
Y_
',...' / ._.
~
W
....
f--'.,.-.\.;,\
_!tt~ t...' "\\,../.' 1'_....
iii >
\ -,
~
.:
..... ..., r-s-,~:,-\"
.
".
',j,,/; .,..... • •
·1.0
,j~;."'\ ~",\'"' \ ...If1 .!! ,,V f ~ ...
-
Naulical Chari
•
,'71.,
(l "
~
,.
S.mula'ed
II:
,,!,,I/
§w
!
>
il II i,'
~~
w
II:
ObseNed
1~
24'00
10
1200 11
24'00
FIG. 11. South Bay Pass
1~ 12
June 1991
~
2400
June 1991
-'me 1991
-114'00
1200 12
2400
1~ 13
1 ,5 I
- 2400
1200 10
I
2400
--L
2400~-i200
1200
12
11
June 1991
FIG. 12. Brazos Santiago Pass
L'·O'-~_:_:::
2400
1200 13
1,500Ir-_,--~---r--,---.---r__,--~--_r--,,--._--r__,--_,
4oori--'---'---T---.---r__'--~--_r--'---'---T---r--'r-_'
Survey
300
~o~~
l~"i n',"" . ,\ \ ~!"i ',V. " ~\ 1~1.t~4'!"
t
I J
200
'
Ul
100
Lt
~'V~
'\
\.t \., \,) ~" ...'~L.;,~\" ~ r
\.
~I 11
"
I \
".. .•
.t
I
IIy
\!\ 11~~~'~!I.f."1 I
I
\11
\
'Y.
.
I
~
~
~
..
~
I I
-100
f1
" . . .'itt"
I
Nil f"1~../11~~,\'~i1
Naullcal Chart
1,000
IL
.
SUlVey
Naulical Chari -loooLIr--L~~~~__~~~L-~L-=-L-~~~~~~~-L~-L~-L~-'
·200~I~~~~L-~~~~~~~~~~-L~~~~~~~~-L~~~=-~~
2
3
4
5
6
7
8
.u.e 1991
9
11
10
12
13
,
14
•
2
3
4
5
6
7 8 June 1991
9
10
11
12
13
14
FIG. 2. Laguna Madre North of Port Mansfield
FIG. 1. South Land Cut
, '·
1,000 r'--~--'--""T""--r--,----r---r-....,..--,-~~-r--~--.--.,
4oor,--~~~-r--'-~~-r--~~~-r--~~---r--~-,
----. Survey
~\'rI I~I
f.
.V VV¥ ~ ~ V Survey
Nautical Chari
I'
~l~,_ I't" VI !, ~ ,
fII
•
FIG. 3. Port Mansfield Channel '1 V,j
"
I!~
i~
~
.
I
II
i
! i,i.! • I· I' ~ 'i! ,I I
.1\
.
l~
II
" t;i.
.,
.
.
Naullcal Charl
I
Ii' ,
i
i~\.~v. .~\i
~
l~fJf~li
.... I I Ii
f
~
'~
i
!
~ II
u.
.~I
0
I
1 ~'
.6oo'Lr--L~~~~~~L-~L-~~~~~~~-L~-L~-L~~~~r-~ 2 3 4 5 6 7 8 9 10 11 12 13 14 June 1991
~\ I!~I 1." 1\
_._._..
I
~.i'i
".1
\, ~
T."I ,
-600 ---L-2,...-L-3:-L-4~~5~~6~--7~--8~--9~ 10 LI
June 1991
FIG. 4. Laguna Madre South of Port Mansfield
"
12
13
14
3Orl---r--'---T---r-~r_-'--~---r---r--~--r-~r_-'---,
loorl---r--..---r-~r--'---r---r---'---..---r--'__~---r--,
50~
I
I
L A~
~, i\~I1I&~
1\Il,A: \~I fJi~11 :' rL'"" ,.... ~"
1_, J
~
w
-'
a:
-A
w
Af\] \1 \V \\.
~
I-
-0.2 -0.4
"'-l "-I
2
3
4
5
6
7 8 9 June 1991
FIG. 3. Port Isabel Tide Station
10
11
12
13
14
15
.0J
~~
2
3
4
5
6
7 8 9 June 1991
FIG. 4. South Bay Tide Station.
10
11
12
13
14
15
1.5 1r----,----,----.-----.---.----,-------.-----,
1.5rl-----,------~-----r----_.------r-----,_----~----_,
~
!
g
g
-'
-' w
iii
~
".....\
~
UJ
>
,~
'i
J
~
>
~
!z ~
n ,.,! \h?/
>-
-' :l
illUJ
Ii 1~
Ul
w
II:
II:
Survey Observed
.1
t
·~400
Observed
'Nautical Shari, 1200 10
2400
1200 11
, I
2400
1200 12
2400
.1.
,
t
~400
1200 13
, Nautical Ehan, 1200 10
2400
1200 11
I
,
I
,
2400
1200 12
2400
1200 13
~ne 1991
.MIe 1991
FIG. 1. South Land Cut
FIG. 2. Port Mansfield Jetties
1.5 ir-----r_----.-----.---.,----,.-----r--~--__,
1.5,r-----~----_r----~-----,------r_----,_-----.----,
~
iii
!
~
~
g
§w
-'
UJ
>
>
!z ~:l
~
Ul
Ul
w
~
5
, ..........
/'--tlt:.:.\
~
• • ....... __,;
•.......1
,_.".
-
•
Survey
-
-1.0 INautical Chart
•
-1~1
, Observe~ 1200 10
2400
2400
~
:::>
1200 12
2400
0.5
.,.'"-.-:...:......
-~"
!,"
01:-
..
.~\
f
F._..,I
,._.-..... .'\ / .:\
.....'.......... ' ....... -.........
/-
- \ ~:;::
•
•
-0.5
~
•
l~t400
,
,
, Observ~ 1200 2400 10
1200 11
2400
2400
1200 13
15 r,----.----.---,.---r---r---r---r---,
4
~
~
~
w
~
~
w
>
>
~
~
'---'''"a
.•
l;"-- - "".~ ;J •
(/)
w
Survey
a:
II:
,-,~
i
..
;~:.. -::~
1 "L .",,;' ~-...
II
~ :::>
~ :::> (/) w
•
•
••
•
_._..
i~"""-·
~,~;_ .•:>.,J
-...
~~
/;,--.. . . -.. . .
'i /
••
f-,-" ,_ ...
Nautlcw Chari
- - - Observed
Nautical Chatt
-0
1200 12
FIG. 6. Old causeway (Mid East)
~
--J
-
June 1991
1.5,
2400
-•
1200 11
'~
Nautical Chart
1200 13
FIG. 5. Old causeway (Eastern)
1200 10
-.
/'
•.~~:"':'I
•.~;:::..,
_..... -
,1 ... -- .... _.,
Survey
June 1991
-1'~400
.....
i"' .... --... ::,·...
-101-
t
t
1200 11
~
-
2400 June 1991
FIG. 7. Old causeway (Mid West)
1200 12
24'00
1200 13
.1.5 1 '2400
•
Observed I
1200 10
2400
I
1200 11
__~ _ _ _ i
2400 June 1991
FIG. 8. Old Causeway (Western)
1200 12
2400
1200 13
1.5,r-----~------_r------,_------r_----~------_r------,_----_,
~ ~
1.5rl----~------r_----,_----_r----~------r_----._--__,
~
0.5
~
~
§
~
w
~
!Z
>
~
!::i
iilw
~
:::>
-
.......~:...
,.~.,
"-
o t--~\ £,.,;;......, \.. . ". \" .'''' . . __ / .
l
--
~ ",-, f·-~ \....~. _A ~ \ ....
\;X i ~ \,,'
.".
~
"
·
-~~ ,...~-~....\.-..... ''\ -. /.-
. .1.•
\, ..."
',,\' ! ••
-0.5
\
~
,..;."/ I •
\. '
\ ...~,l ~ .... l
-1
·1.0 ~ _._._.. NaubCal CharI
•
-
//'\~\ ! \ i' !,,'
.,j , _It
w
>
I
,. / l/
,/'
, I
,;;
!::i :::>
f "... 1-.. . "
~
I
I
,.\ !/ \\ ..
/
"
f .1.,,'
1:!OO 10
2400
1200 11
2.wa
FIG. 11. South Bay Pass
1200 12
2400
1:!OO 13
~
·1.0
.li400
1200 10
2400
1 24 00
1200 11
June 1991
FIG. 12. Brazos Santiago Pass
1200 12
2400
,, I
I
!,.,.,
\
Observed
June 1991
o
,! ,,
§
,., .....,
,
