hydrodynamic modeling, wave analysis & sedimentation

SDMS DOCID# 1137769

HYDRODYNAMIC MODELING, WAVE ANALYSIS

AND SEDIMENTATION EVALUATION

FOR THE YOSEMITE CANAL WETLAND RESTORATION PROJECT

SAN FRANCISCO, CA

Prepared for:

California State Parks Foundation

Prepared by:

Noble Consultants, Inc

September 2005

NOBlE CONSULTANTS, INC.

TABLE OF CONTENTS

1.0 INTRODUCTION ............................................................................................................. 1-1

2.0 FIELD DATA COLLECTION ........................................................................................... 2-1

2.1 BATHYMETRICSURVEY ............................................................................................................. 2-1

2.2 HYDROLOGIC DATA MEASUREMENT ........................................................................................ 2-1

2.3 TIDAL CHARACTERISTICS AT HUNTERS POINT ........................................................................ 2-2

2.4 SOIL SAMPLING ......................................................................................................................... 2-2

3.0 TIDAL CIRCULATION AND SEDIMENT TRANSPORT SIMULATION TECHNIQUES .. 3-1

3.1 MODEL DESCRIPTION ................................................................................................................ 3-1

3.1.1 RMA2 Model .................................................................................................................... 3-1

3.1.2 SED2D Model .................................................................................................................. 3-2

3.2 MODELED AREA AND BATHYMETRY ......................................................................................... 3-2

3.3 RMA2 BOUNDARY CONDITIONS .............................................................................................. 3-4

3.4 RMA2 MODEL CALIBRATION .................................................................................................... 3-4

3.5 SED2D BOUNDARY CONDITIONS ............................................................................................ 3-4

3.6 SED2D MODEL PARAMETERS ................................................................................................. 3-5

3.7 SIMULATED PROCEDURES ........................................................................................................ 3-6

4.0 ASSESSMENT OF TIDAL HYDRODYNAMICS ............................................................. A-1

4.1 EXISTING CONDITIONS .............................................................................................................. 4-1

4.1.1 Water Depth ..................................................................................................................... 4-1

4.1.2 Tidal Currents .................................................................................................................. 4-2

4.2 PROJECT CONDITIONS .............................................................................................................. 4-2

4.2.1 Water Depth ..................................................................................................................... 4-2

4.2.2 Tidal Currents .................................................................................................................. 4-3

5.0 ASSESSMENT OF SEDIMENT TRANSPORT UNDER TIDAL FLOW CONDITIONS ... 5-4

5.1 ExiSTING CONDITIONS .............................................................................................................. S-4

5.1.1 Bed Change ..................................................................................................................... S-4

5.1.2 Bottom Shear Stress ....................................................................................................... S-5

5.2 PROJECT CONDITIONS .............................................................................................................. S-5

5.2.1 Bed Change ............... , ..................................................................................................... 5-5

5.2.2 Bottom Shear Stress ....................................................................................................... 5-5

6.0 STORM WAVE CLIMATES AND WAVE-INDUCED EROSION ..................................... 6-1

6.1 OFFSHORE STORM WAVES OF SOUTH BASIN ......•..•.•...••••....................••••.....•••••••..........••....•• 6-1

6.1.1 Wind-Wave Hindcasting ................................................................................................. 6-1

6.1.2 Storm Waves versus Return Periods ........................................................................... 6-1

6.2 STORM WAVE CLIMATES IN SOUTH BASIN AND PROJECT AREA ...•.•.•........•••.......•.............•.•• 6-2

6.2.1 STWAVE Model Setup ................................................................................................... 6-2

6.2.2 Existing Conditions .......................................................................................................... 6-3

6.2.3 Project Conditions ........................................................................................................... 6-3

6.3 ASSESSMENT OF WAVE-INDUCED BED EROSION FOR PROJECT CONDITIONS ..................... 6-4

7.0 REFERENCES ................................................................................................................ 7-7

ii

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Figure 1-1

Figure 2-1

Figure 2-2

Figure 2-3

Figure 2-4

Figure 3-1

Figure 3-2

Figure 3-3

Figure 3-4

Figure 3-5

Figure 4-1

Figure 4-2

Figure 4-3

Figure 4-4

Figure 4-5

Figure 4-6

Figure 4-7

Figure 4-8

Figure 4-9

Figure 4-10

Figure 4-11

Figure 4-12

Figure 4-13

Figure 4-14

Figure 4-15

Figure 4-16

Figure 4-17

Figure 4-18

Figure 5-1

Figure 5-2

Figure 5-3

LIST OF FIGURES

Project Site

Surveyed Bathymetry of Yosemite Canal and South Basin

Surveyed Bathymetry of the Project Area

Measured Water Levels Compared to Hunters Point

Measured Tidal Current Velocities

Finite Element Mesh (Existing Condition, Whole Domain)

Finite Element Mesh (Existing Condition, Project Area)

Finite Element Mesh (Project Condition, Project Area)

Modeled Bathymetry (Project Condition, Project Area)

Simulated Tidal Stage and Current Compared to Measurement

Simulated Water Depth During a Low Tide (Existing Condition, Whole Domain)

Simulated Water Depth During a High Tide (Existing Condition, Whole Domain)

Simulated Water Depth During a Low Tide (Existing Condition, Project Area)

Simulated Water Depth During a High Tide (Existing Condition, Project Area)

Simulated Time Series of Water Depth for Existing Condition

Simulated Inundation Frequency (Existing Condition, Project Area)

Simulated Flood Currents (Existing Condition, Whole Domain)

Simulated Ebb Currents (Existing Condition, Whole Domain)

Simulated Flood Currents (Existing Condition, Project Area)

Simulated Ebb Currents (Existing Condition, Project Area)

Simulated Time Series of Current Speed for Existing Condition

Predicted Water Depth During a Low Tide (Project Condition, Project Area)

Predicted Water Depth During a High Tide (Project Condition, Project Area)

Predicted Time Series of Water Depth for Project Condition

Predicted Inundation Frequency (Project Condition, Project Area)

Predicted Flood Currents (Project Condition, Project Area)

Predicted Ebb Currents (Project Condition, Project Area)

Predicted Time Series of Current Speed for Project Condition

Simulated Bed Change (Existing Condition, Whole Domain)

Simulated Bed Change (Existing Condition, Project Area)

Simulated Bottom Shear Stress Induced by Flood Currents

(Existing Condition, Project Area)

iii

I

Figure 5-4

Figure 5-5

Figure 5-6

Figure 5-7

Figure 6-1

Figure 6-2

Figure 6-3

Figure 6-4

Figure 6-5

Figure 6-6

Figure 6-7

Simulated Bottom Shear Stress Induced by Ebb Currents

(Existing Condition, Project Area)

Predicted Bed Change (Project Condition, Project Area)

Predicted Bottom Shear Stress Induced by Flood Currents

(Project Condition, Project Area)

Predicted Bottom Shear Stress Induced by Ebb Currents


Occurrence Frequency of Wind Directions

Wind Fetches at Bayside of South Basin

Hindcasted Wave height at Bayside of South Basin

Modeled Cartesian Grid and Water Depth (Existing Condition, Whole Domain)

Simulated Wave Height for 50-Year Offshore Wave

(Existing Condition, Whole Domain)

Simulated Wave Height for 1 0-Year Offshore Wave


Simulated Wave Height for 1-Year Offshore Wave


Figure 6-8 Modeled Cartesian Grid and Water Depth (Project Condition, Project Area)

Figure 6-9 Predicted Wave Height for 50-Year Offshore Wave


Figure 6-1 0 Predicted Wave Height for 1 0-Year Offshore Wave


Figure 6-11 Predicted Wave Height for 1-Year Offshore Wave


Figure 6-12 Wave-Induced Erosion at Location E6 During 50-Year Wave Event

Figure 6-13 Wave-Induced Erosion at Location E9 During 50-Year Wave Event

iv

Table 2-1

Table 3-1

Table 6-1

Table 6-2

LIST OF TABLES

Tidal Characteristics at Hunters Point, San Francisco Bay, CA

Model Mesh Elements and Nodes

Hindcasted Offshore Waves at the Bayside Boundary of South Basin

Potential for bed Erosion Induced by the 1 0-Year to 50-Year Wave Events

v

HYDRODYNAMIC MODELING, WAVE ANALYSIS AND SEDIMENTATION

EVALUATION FOR THE YOSEMITE CANAL WETLAND RESTORATION PROJECT

SAN FRANCISCO, CA

1.0 INTRODUCTION

This technical report was prepared to document the results of the numerical modeling study

together with field data collection that was been conducted by Noble Consultants Inc. (NCI) for

the Yosemite Wetland Restoration Project in San Francisco, CA. The site location is shown in

Figure 1-1.

The purpose of the study was to assist in the evaluation and design of the Yosemite Canal

Wetlands Restoration Project. The main objectives of the study were to investigate (1) the

typical tidal hydrodynamic condition, (2) the potential for sedimentation or scouring under the

typical tidal flow condition, (3) wave conditions during storm events, and (4) the potential for bed

erosion from wave hydrodynamics during storm events. Both the existing condition and the

future condition associated with the proposed project plan were investigated in the study.

The field data collection was conducted to provide the basis for establishing the existing

bathymetry and for model calibration. The field data collection efforts included a hydrographic

bathymetric survey within Yosemite Canal and the South Basin, topographic mapping using

aerial photographic techniques, field hydrologic measurements of water surface elevation and

tidal current velocity, and soil sampling.

The modeling study includes both the hydrodynamic simulation and sediment transport

simulation for the Yosemite Canal and South Basin. The RMA2 model was used for the

simulation of typical tidal circulation, the STWAVE model was used for the prediction of wave

climates during storm events, the SED2D model was applied for the estimate of sediment

suspension and bed change under typical tidal flow condition, and potential bed erosion under

extreme storm condition was estimated using empirical relations derived from Sedflume tests on

field data.

1-1

2.0 FIELD DATA COLLECTION

2.1 Bathymetric Survey

Field data collection was required to establish the baseline bathymetry and topography within

the Yosemite Canal and South Basin in order to perform the numerical modeling study. NCI

hydrographic survey crew conducted a hydrographic survey of the project area between

Hunters Point on the north, Candlestick Park on the south and Yosemite Canal on the west.

The survey was conducted during high tide periods between September 22, 2003 and

September 25, 2003. A tide gage that was deployed in the marina at Oyster Point was

referenced to a National Oceanographic and Atmospheric Administration (NOM) tidal

monument at the marina. In addition to the hydrographic survey, aerial topographic mapping

techniques were used to create a topographic map of the land based on aerial photography

taken in November 2003 at a 1-foot contour interval accuracy. Figure 2-1 shows the derived

bottom elevation contour of Yosemite Canal and South Basin generated based on the collected

bathymetric and topographic data. The detailed view of the existing bottom elevation contour in

the project area is shown in Figure 2-2. The water depth was found to be shallower than -1.8

meters, North American Vertical Datum (NAVD88) for the South Basin, and shallower than +0.4

meter, NAVD88 for Yosemite Canal.

2.2 Hydrologic Data Measurement

Hydrologic data were collected in order to provide bayside (offshore) boundary conditions for

the RMA2 model simulation and to calibrate the RMA2 model parameters. Two water level

gages were deployed within the survey area from September 24, 2003 to October 13, 2003.

One gage was installed in the inner basin at a location of E1 ,834,451, N636,888 (meters,

California State Plane Zone 3), and the other was in the outer basin at a location of E1 ,834,899,

N636,558, as shown in Figure 2-3. The measured water surface elevations at the inner and

outer gages, as compared to the NOM predicted data at Hunters Point, are shown in Figure 2-

4. A tidal fluctuation ranging from -0.14 meters to 2.19 meters was measured in the South

Basin for the data collection period. The measurements agreed with the NOM predicted tidal

level at Hunters Point.

During the same period an Aquadopp Current Meter was installed adjacent to the inner water

level gage, as shown in Figure 2-3, to measure the flow current velocity components (velocity in

2-1

the x, y, and z directions). Figure 2-5 shows the horizontal components of the current velocity

(x and y directions) and the resultant horizontal magnitude. Weak tidal currents with

magnitudes less than 0.15 meter per second (m/s) were measured in the South Basin.

2.3 Tidal Characteristics at Hunters Point

The NOAA water level station closest to Yosemite Canal is located at Hunters Point

(Station ID: 9414358) at North 37°43.8', West 122°21.4', within San Francisco Bay. The tidal

datum epoch of this station can be used as the reference for Yosemite Canal and South Basin.

The tidal characteristics established by the NOAA at Hunters Point station for both the old

epoch (1960-1978) and new epoch (1983-2001) are presented in Table 2-1.

Table 2-1 Tidal Characteristics at Hunters Point, San Francisco Bay, CA

(NOAA Station ID: 9414358)

Datum Plane Elevation, meters Elevation, meters

(Epoch: 1983-2001) (Epoch: 1960-1978)

Highest Observed Water Level (12/27/74) - 2.49

Mean Higher High Water (MHHW) 2.07 2.05

Mean High Water (MHW) 1.88 1.86

Mean Tide Level (MTL) 1.11 1.10

Mean Sea Level (MSL) 1.08 -NGVD29 - 0.95

Mean Low Water (MLW) 0.34 0.34

NAVD 88 - 0.13

Mean Lower Low Water (MLLW) 0.00 0.00

Lowest Observed Water (12/01/1975) - -0.57

2.4 Soil Sampling

Sediment surface grab samples to determine grain size characteristics were taken at three

locations as shown in Figure 2-3: in the outer South Basin (S1 ), in the Inner South Basin (S2),

and in Yosemite Canal (S3). Hydrometer tests were conducted on the soil samples in order to

2-2

determine the grain size of the bed material. The sediment grain size distributions at the three

locations were similar. The average median grain size at the three locations was approximately

0.005 millimeters.

2-3

3.0 TIDAL CIRCULATION AND SEDIMENT TRANSPORT SIMULATION TECHNIQUES

3.1 Model Description

Two models within the Surfacewater Modeling System (SMS) software package, RMA2 and

SED2D, were used to simulate the two-dimensional tidal circulation, sediment transport and

resulting sedimentation or erosion within Yosemite Canal and the South Basin.

3.1.1 RMA2 Model

The RMA2 modeling program computes the water surface elevation and horizontal velocity for

sub-critical, free-surface flow in two-dimensional flow fields. This particular model module is well

suited for and has been extensively applied to the simulation of complex riverine and tidal

hydrodynamics of rivers, bays and estuaries.

RMA2 computes a finite-element solution of the Reynolds form of the Navier-Stokes equations

for turbulent flows (Norton and King, 1977). The bottom friction is defined from the Manning's or

Chazy equation. Turbulent energy is represented by an eddy viscosity analogy. Forces

generated from wind and Coriolis effects can also be included. The formulation, including the

depth-integrated equations of fluid mass and momentum conservation, is presented as follows:

au au au h ( a2u a2u) (aa ah) h-+hu-+hv--- E -+E - +gh -+- +T +T +Q =0 at ax ay p .U ax2

X)' By2 ax ax bx S:JC X

av av av h ( a2v a2v) (aa ah) h-+hu-+hv--- E -+E - +gh -+- +T +T +Q =0 at ax ay p yx ax2 yy By 2 ay ay by sy y

where his the water depth, u and v are the horizontal flow velocity components, x, y and tare

the Cartesian coordinates and time, pis the water density, g is the acceleration of gravity, Exx,

Ew are the eddy viscosity coefficients in the normal directions on x and y axis surface, Exy and

Eyx are the eddy viscosity in the shear direction on each surface, Tbx and Tby are the bottom

friction components, Tsx and Tsy are the surface wind stress components, and Ox and Oy are the

Coriolis stress components.

3-1

3.1.2 SED2D Model

The SED2D modeling program is a generalized finite-element computer code for two

dimensional, vertically averaged suspended sediment transport in open channel flows. The

SED2D uses input of the hydrodynamic parameters such as the water surface elevation and

flow velocity that are computed from the RMA2 or another equivalent hydrodynamics model.

The formulation for sediment transport used in SED2D is the convection-diffusion equation that

can be derived from the mass conservation of sediment {Ariathurai et. al, 1977), and the

equation is:

where C is the sediment concentration, Dx and Dy are the effective sediment diffusion

coefficients in x- and y-directions, respectively, the flow velocity components u and v are

provided by RMA2, and S is the bed source term that quantifies the net sediment exchange at

the bottom between the flow and the bed.

It is assumed in SED2D that clay in transport will remain in suspension as long as the bed shear

stress exceeds the critical value for deposition, and simultaneous deposition and erosion of clay

do not occur. When the shear stress is less than the critical shear value for deposition, the

source termS i~ computed based on Krone's (1962) equation for deposition rate of clay beds.

When the shear stress exceeds the critical shear stress for erosion, the source term S is

computed by a simplification of Partheniades (1962) results for erosion rate of clay beds. When

the shear stress exceeds the bulk shear strength of the layer, the erosion source term is

estimated by assuming mass failure occurs over a whole bed layer.

3.2 Modeled Area and Bathymetry

The primary area of interest is Yosemite Canal. To minimize the boundary-induced error, the

modeled domain covers an expanded area including both Yosemite Canal, and a major part

{approximately 1 kilometer in length) of the South Basin.

3-2

A finite element mesh consisting of 1 , 798 elements and 5,543 nodes was developed to

characterize the entire modeled area for the existing without-project condition, as illustrated in

Figure 3-1. The mesh configuration in the project area has approximately 800 elements and

2,500 nodes, as shown in Figure 3-2.

The finite element mesh for the project condition was developed by modifying the mesh system

for the existing condition in accordance with the proposed project plan. The major modification

was to create elements for the proposed tidal embayments. The modeled domain for the

project condition was represented by a mesh system of 2,295 elements and 7,020 nodes,

among which approximately 1 ,300 elements and 4,000 nodes are located in the project area.

The mesh system at the project site is shown in Figure 3-3 for the project condition. The mesh

systems for the existing and project conditions are summarized in Table 3-1.

Table 3-1: Model Mesh Elements and Nodes

Modeled Scenarios Number of Elements Number of Nodes

Existing Entire Domain 1,798 5,543

Condition Project Area 800 2,500

Project Entire Domain 2,295 7,020

Condition Project Area 1,300 4,000

The initial bathymetry used in the model simulation for the existing condition was constructed

based on the bathymetric and topographic surveys and on the supplementary data derived

using the aerial photo mapping techniques, as shown in Figure 2-1. The bathymetry for the

project condition was developed based on the proposed grading plan. Figure 3-4 shows the

bathymetry of the project area for the proposed plan. Three embayments (NW, NE & SE) exist

in the plan. The southeast (SE) area is the shallowest, with a typical bottom elevation at Mean

Higher High Water (MHHW), approximately 2.0 meters NAVD88. The bottom elevations in the

northwest (NW) and northeast (NE) areas range from about Mean Tide Level (MTL) of

approximately 1.0 meter NAVD88 to MHHW of 2.0 meters NAVD88. Islands, with crest

elevations of approximately 2.4 meters NAVD88 are located in the NE and SE areas.

3-3

3.3 RMA2 Boundary Conditions

The boundary conditions required in the RMA2 hydrodynamic simulation includes the upstream

flow rate and downstream water surface elevation. Since the hydrodynamic simulation focuses

on tidally dominated hydrologic conditions, it is assumed that no flow discharges through the

upstream boundary of the canal. The water surface elevation measured by the outer gage, as

shown in Figure 2-4, was used as the downstream water level condition at the bayside

(offshore) boundary of the RMA2 simulation.

3.4 RMA2 Model Calibration

The model parameters such as the Manning's roughness coefficient (n) and the turbulent eddy

viscosity (E) required in the RMA2 simulations were calibrated by matching the model

simulation with the water surface elevation data measured by the inner gage and the tidal

current velocity data collected by the current meter. The calibrated values were found to be

0.023 for the Manning's roughness coefficient (n) and 5,000 Pascal-second for the turbulent

eddy viscosity (E). Both assigned coefficients are within the range of values recommended by

the RMA2 User's Manual. The comparisons of the water surface elevation and current velocity

at the inner gage location between the model prediction and measurements are shown in

Figure 3-5. This figure shows the model simulations agree withmeasured data.

Sensitivity analysis was also conducted to investigate the sensitivity of simulated results to the

model parameters of Manning's roughness coefficient and the turbulent eddy viscosity. It was

found that model results are not sensitive to the two model parameters. This is because the

tidal circulation in the South Basin and in Yosemite Canal is essentially driven by the temporal

fluctuation of water level in the Bay. In addition, the dimension of the modeled domain is

relatively small, which also limits the effect of the model parameters on simulated results.

3.5 SED2D Boundary Conditions

The boundary conditions required in the SED2D simulation include the suspended sediment

concentration (SSC) at model boundaries. Since no flow passes through the upstream

boundary of the canal, no boundary condition was assigned at this location. The SSC at the

bayside boundary was specified based on the sse data that was collected by USGS

(Buchanan, et al, 1995 to 2004) in San Francisco Bay from 1993 to 2002. The two stations of

3-4

USGS SSC data collection that are close to the project site are at Pier 24 in Central Bay and at

the San Mateo Bridge in the South Bay. The mean sse measured at the middle depth of water

body averaged between 1993 to 2002 was approximately 0.0291 kg/m3 at Pier 24, and was

0.0515 kg/m3 at San Mateo Bridge. The average value of the two stations, or 0.0403 kg/m3,

was specified as the effective sse at the bayside boundary.

It is noted that the sse in San Francisco Bay depends on tidal currents and sediment source of

the Bay, and significant temporal variation may occur. However, detailed information about the

temporally varying SSC is not generally available and uncertainty may also be present in the

data because of the state of art for sse measurement. Therefore, a single value of the

effective SSC was specified at the bayside boundary. Using a single value of SSC at the

boundary to represent temporally varying SSC may affect the accuracy in estimating short-term

sediment transport. However, the effect should be limited for a long-term estimate, of interest in

this study, and particularly for the project area that is away from the boundary.

3.6 SED2D Model Parameters

Accuracy of SED2D model results significantly depends on the appropriate selection of

sediment properties that are used as model input parameters. The bed material of the project

site consists of clay and silt. The major parameters required by the SED2D model for clay

sediment transport simulation include settling velocity of sediment particles, critical shear

stresses for deposition and for erosion, erosion rate coefficient and dry density of bed material.

These parameters were specified based on the collected field data and on the supplementary

information about the model parameters obtained from references.

Based on the hydrometer tests on the soil samples on the project site, a median sediment grain

size of 0.005 millimeters was used in the model. A settling velocity of 0.141 cm/s for a sediment

particle of a median grain size of 0.005 millimeters (Cheng, 1997) was specified in the model.

The dry density of the bed material was not directly measured in this study. Instead, it was

estimated based on a Sedflume analysis that was conducted on the field sediment samples

obtained from the South Basin by Battelle et al (2005). Based on analysis, the dry density of the

bed material was specified as 480 kg/m5 for the top bed layer with a depth up to 5 centimeters,

3-5

----------------------

590 kg/m5 for the second layer with a depth between 5 and 1 0 centimeters, and 660 kg/m5 for

the deeper layers.

When the shear stress exceeds the critical value for erosion, the source term is computed in

SED2D using the simplified linear relation between the erosion rate and the shear stress

(Partheniades, 1962). The critical shear stress for noticable erosion is typically larger than 0.5

Pa for the San Francosco Bay mud, above which erosion rates increases very rapidly with the

shear stress. The critical shear stress for suspended mud to deposit on the bed is

approximately 0.06 Pa. Based on Partheniades (1965), only minor erosion occurs when the

shear stress is between the critical value for mud deposition and that for noticeable mud

erosion. The erosion rate coefficient, which is defined as the erosion rate of bed material per

unit area per unit increase of flow shear stress normalized by the critical shear stress for

erosion, is only on the order of 104 g/m2/sec for the minor erosion regime, or approximately 100

times smaller than that for the noticeable erosion regime.

The shear stress generated by tidal currents in the project area is generally less than 0.5

Pascals (Pa). This range of shear stress mainly causes minor erosion when the shear stress

exceeds the critical shear stress of 0.06 Pa. Therefore, the linear relation between the erosion

rate and the shear stress for the minor erosion regime, instead of that for noticable erosion

regime, was used in the simulation. Based on Partheniades's (1965) experiments, a critical

shear stress for erosion of 0.06 Pa with an erosion rate coefficient of 8x1 o-5 g/m2/sec were

specified in the SED2D simulation to determine the source term when erosion occurs.

3.7 Simulated Procedures

In the model simulation, RMA2 was first executed to compute the flow conditions using the

water level measured by the outer tidal gage in the South Basin for 15 days starting from

September 25, 2003. SED2D was subsequently run for the same 15-day period using the flow

conditions computed by RMA2. The 15 days of simulation period roughly covers a spring and a

neap tide cycle. The time step was 0.2 hours in the RMA2 simulation and 0.1 hours in the

SED2D simulation.

3-6

The simulated results of the 15 days simulation period were then used to assess the existing

tidal circulation and sediment transport in the South Basin and in the Yosemite Canal, as well as

the potential change that will be caused by the wetland restoration project.

3-7

4.0 ASSESSMENT OF TIDAL HYDRODYNAMICS

4.1 Existing Conditions

4.1.1 Water Depth

Figures 4-1 and 4-2 show the simulated water depths for the whole modeled area during a low

tide and a high tide, respectively. Detailed views of water depth for the project area are shown

in Figures 4-3 and 4-4. The model results indicate that periodic wet and dry processes (wet at

high tide and dry at low tide} occur within the entire Yosemite Canal and in a small section of the

South Basin as tidal elevation varies. The whole area will be inundated during a high tide. The

water depth was estimated to be approximately two to four meters in the South Basin, and

approximately 0.8 to 1.6 meters in the canal. However, all of Yosemite Canal dries out (has no

water} at low tide.

Figure 4-5 shows the time series of the simulated water depth at six reference stations along

the main flow path from the Yosemite Canal to the outer South Basin. locations of the six

reference stations are shown in Figure 2-3. The results for the simulation period indicate some

wetting and drying at Locations 1 to 4, although minimal at Location 4, and no drying at

Locations 5-6. Temporal variations can be found in the water depth from the canal to the South

Basin in response to the tidal fluctuations.

Figure 4-6 shows the water inundation frequency in the project area that was calculated based

on the simulated water depth for 15 days. The inundation frequency represents the percent of

time that the site is inundated with water. An inundation frequency of 1.0 indicates the site is

always inundated, and zero indicates the site is always dry. Most of the South Basin is

inundated with an inundation frequency of 1.0. The inundation frequency was found to be

approximately 40 to 50 percent in the inner segment of the canal, 60 to 70 percent in the middle

segment, and 70 to 80 percent in the lower segment.

4-1

--~-------

4.1.2 Tidal Currents

A snapshot of the simulated tidal current velocity vectors together with water depth contours for

a flooding tide is demonstrated in Figure 4-7. Figure 4-8 shows the flow field for an ebbing

tide. Figures 4-9 and 4-10 show detail views in the project area. The time series of the

simulated current velocity magnitude at the six reference stations (see Figure 2-3, L 1 to L6 ) are

shown in Figure 4-11.

Circulation in the South Basin was found to be very restricted and the tidal currents are weak.

The maximum current velocity was calculated to be approximately 0.1 meters per second, which

occurs in the narrow part of the South Basin during the strongest flood and ebb tides. Tidal

currents in Yosemite Canal were slightly stronger, particularly in the middle and lower segment

of the canal. The maximum current velocity is approximately 0.25 meters per second, which

occurs in the middle and lower canal and lower segment of the canal during the strongest flood

and ebb tides. These velocities are considered low, and not likely to induce noticeable re

suspension of bed material or bed scouring.

4.2 Project Conditions

The hydrodynamic conditions within Yosemite Canal and the South Basin for the proposed

project were simulated based on the bathymetry shown in Figure 3-3. The same time series of

water level measured for 15 days was specified as the bayside boundary condition. Since the

change to the hydrodynamic conditions in the outer South Basin is negligible, the analysis

focuses on the change that will occur in the project area.

4.2.1 Water Depth

Figures 4-12 and 4-13 show the predicted water depths in the project area during a low tide

and a high tide, respectively. Figure 4-14 shows the time series of the predicted water depth at

the six reference stations. The open water surface area during high tides will be significantly

increased over the existing condition as shown in Figure 4-13. Since the elevation of the

embayments is relatively high, the open water area during low tide will be similar to the existing

condition. The water depth during high tides will range between 0.2 and 0.4 meters in the NW

embayment, between 0.2 and 1.2 meters in the NE embayment, and less than 0.2 meters in the

SE embayment. These areas will dry out during low tides.

4-2

--- ~- ~----- ~~

Figure 4-15 shows the predicted inundation frequency contours. The model results indicate

that the proposed project will not significantly alter the water depth in Yosemite Canal or in the

South Basin. Periodic wet and dry processes will still occur within the Canal and in the inner

South Basin as tidal elevation varies. Figure 4-15 suggests that the inundation frequency will

range between 1 0-20 percent in the NW embayment, will range between 1 0-50 percent in the

NE area, and will be approximately 10 percent in the SE area.

4.2.2 Tidal Currents

Figures 4-16 shows a snapshot of the predicted tidal current velocity vectors at maximum

currents velocity in the canal, together with water depth contours for a flooding tide, and Figure

4-17 shows the flow field for an ebbing tide. Because of the relatively high bottom elevations,

the three proposed embayments are dry when strong flood and ebb currents occur in the canal,

as shown in Figures 4-16 and 4-17. Tidal circulation during high tides when these areas are

inundated is essentially weak. Therefore, tidal circulation in the proposed embayments will be

generally much weaker than the canal, and the chance for the bed material in those areas to be

re-suspended by tidal currents is even less than in the canal.

The time series of the predicted current velocity magnitude at the six reference stations are

shown in Figure 4-18. By comparing Figure 4-11 (existing conditions) with Figure 4-18 it is

seen that the proposed project will not significantly alter the tidal circulation in Yosemite Canal

or in the South Basin. Circulation in the South Basin will still be very weak, and the maximum

current velocity will still be approximately 0.25 meters per second within the canal during the

strongest flood and ebb tides. These low flow velocities will not likely be able to induce

noticeable re-suspension of bed material or bed scouring in the project area.

4-3

I

I

5.0 ASSESSMENT OF SEDIMENT TRANSPORT UNDER TIDAL FLOW CONDITIONS

The sediment transport induced by tidal circulation was simulated using the SED2D model,

which used the tidal circulation parameters computed by RMA2 for 15 days. The simulated

results, including the bed change and bottom shear stress, were then analyzed in order to

assess the long-tern bed deposition or erosion, and the likelihood of sediment re-suspension in

the project area. Both the existing and the project conditions were assessed.

5.1 Existing Conditions

5.1.1 Bed Change

Figure 5-1 shows the annual bed change converted from the predicted bed deposition or

erosion extrapolated using the typical tidal conditions for 15 days. The results indicate that the

sediment bed in the South Basin and in Yosemite Canal appears to be relatively stable and

undisturbed. The annual erosion rate or deposition rate does not exceed 2 centimeters per year

under typical tidal flow conditions.

Except for the main flow path, where negligible erosion occurs, insignificant sediment deposition

occurs in most of the South Basin under typical tidal flow conditions. The erosion rate along the

main flow path was found to be less than 0.5 centimeter per year, and the estimated sediment

deposition rate ranges from 1.0 to 1.5 centimeters per year in the outer South Basin, and is less

than 1 centimeter per year for the inner basin.

Figure 5-2 shows the detailed view of the predicted annual bed change in the project area. As

a result of the weak currents, sedimentation generally occurs in the inner South Basin next to

the project site. However, minor scouring occurs in most of Yosemite Canal, and in the mouth

of the canal because of the elevated current velocities in these areas. However, the erosion

rate is minor, estimated to be less than 0.5 centimeters per year in the mouth, less than 1

centimeters per year in the middle and lower segment of the canal, and less than 0.5

centimeters per year in the upper portion. Negligible sediment deposition occurs at the furthest

end of the canal because of the weak current in this dead-end area. It is noted that the channel

is relatively deeper in the segments where erosion occurs. This is also found in the surveyed

bathymetry as shown in Figure 3-4.

5-4

------ -------

5.1.2 Bottom Shear Stress

Bottom shear stress exerted by the flow on the bed is responsible for re-suspending bed

material. Figure 5-3 shows a snapshot of the predicted bottom shear stress induced by flood

currents, and Figure 5-4 shows that induced by ebb currents. The results indicate that the

maximum bottom shear stress is approximately 0.2 Pa (or N/m2) during flood currents, and 0.6

Pa during ebb currents.

Based on sediment properties in San Francisco Bay (Partheniades, 1962, 1965, and Battelle,

2005), noticable clay sediment erosion would occur only when the bed shear stress generally

exceeds 0.5 Pa or more, below which only minor erosion occurs. Although model results

indicate that the maximum bed shear stress can reach 0.6 Pa during ebb currents, this shear

stress only exists for a very short period of time (in an order of minutes) when the local water

depth is very minimum. Therefore, tidal currents are not likely to induce significant re

suspension of local bed material in the Yosemite Canal under the typical tidal flow conditions.

5.2 Project Conditions

5.2.1 Bed Change

The predicted annual bed change under typical tidal flow conditions for the project condition is

shown in Figure 5-5. Compared to the existing condition, the proposed project will not

significantly alter the shoaling or scouring pattern within Yosemite Canal. Similar to that for the

existing condition, minor scouring occurs in most of Yosemite Canal, with an erosion rate less

than 1 centimeters per year for the middle and lower segment of the canal, and less than 0.5

centimeters per year for the upper portion. A similar shoaling pattern was predicted for the

upper end of the canal.

Sediment accumulation was predicted in the three proposed embayments because of the weak

currents that will exist in these areas. However, the annual deposition rate will be less than 0.5

centimeters per year, which is considered negligible.

5.2.2 Bottom Shear Stress

5-5

The bottom shear stress for the project condition is shown in Figure 5-6 for flood currents, and

in Figure 5-4 for ebb currents. The maximum bottom shear stresses predicted for the project

condition during the flood and the ebb currents have similar magnitudes to the existing

condition. This is consistent to the negligible alternation to the peak flood and ebb current

condition in the project area that will be caused by the proposed plan. Similar to the existing

condition, tidal currents will not likely induce significant re-suspension of local bed material in

Yosemite Canal under the typical tidal flow conditions.

5-6

6.0 STORM WAVE CLIMATES AND WAVE-INDUCED EROSION

6.1 Offshore Storm Waves of South Basin

Waves propagating from the bayside boundary (offshore) of the South Basin to the project area

are generated by the winds blowing over the water surface of the South San Francisco Bay.

The wave climates at the offshore of South Basin are determined by the wind conditions in this

area.

6.1.1 Wind-Wave Hindcasting

A 57 -year record of continuous wind measurements at the San Francisco International Airport

were used for hindcasting the waves at the offshore of the South Basin. The wind rose derived

from the hourly wind directions for the 57 years of record from 1948 to 2004 is shown in Figure

6-1. The 16 azimuth directions are shown along with the percentage of time winds are from that

direction. This figure shows that the prevailing winds in the area are westerly, blowing from the

west (W) and north-west-west (NWW). Since the South Basin is open to the southeast, the

storm waves that can propagate to the project area are generated by the southeast storm winds

blowing over the South San Francisco Bay from approximately the south-east-east (SEE) to

almost south-south-east (SSE). The wind fetches for these directions are shown in Figure 6-2.

The wind-generated waves at the offshore of the South Basin were hincasted using the wave

prediction model in the Automated Coastal Engineering System (ACES) that was developed by

the U.S. Army Corps of Engineers. ACES is a comprehensive set of software programs for

applying a broad spectrum of coastal engineering design and analysis technologies, including

wave prediction. The shallow water restricted wind fetch option within the wave prediction

model was used in this analysis.

6.1.2 Storm Waves versus Return Periods

The hourly offshore wave condition at the offshore of South Basin was estimated based on the

hourly wind data. The annual maximum wave condition was then derived for each of the 57

years, from which the wave heights for various return periods (years) were formulated, as

shown in Figure 6-3. Also shown in this figure is the Weibull distribution that best fits the data.

6-1

The 50-year, 1 0-year and 1-year offshore waves estimated based on this return frequency

analysis are sown in Table 6-1.

Table 6-1 Hindcasted Offshore Waves at the Bayside Boundary of South Basin

Return period (year) Wave height (m) Wave period (sec)

50 1.42 4.4

10 1.26 4.2

1 0.70 3.2

6.2 Storm Wave Climates in South Basin and Project Area

The offshore waves during extreme storm events were propagated to the South Basin and the

project area using the nearshore wave transformation model STWAVE. The wave climates

associated with the 50-year, 10-year, and 1-year offshore wave conditions were predicted.

6.2.1 STWAVE Model Setup

The STWAVE (STeady-state spectral WAVE) model was developed by U.S. Army Corps of

Engineers for nearshore wave transformation (Smith et. al, 2001). STWAVE can be applied to

quantify the change in wave parameters (wave height, period, direction and spectral shape)

from offshore to the nearshore zone, where waves are strongly influenced by variations in

bathymetry, water level, and current. It is capable of simulating wave shoaling, refraction,

diffraction and breaking, wind-wave growth due to local sea breeze, and wave-wave interaction

and whitecapping that redistribute and dissipate energy in a growing wave field. STWAVE

solves the steady-state conservation of spectral wave action along backward traced wave rays

with source/sink terms, and the governing equations are numerically solved using finite

difference methods on a Cartesian grid.

The modeled domain in the STWAVE simulation covers a rectangular area of 2000 meters

cross-shore and 1300 meters alongshore, with a cell size of 10 meters by 10 meters. The

Cartesian grid used in the simulation is shown in Figure 6-4 for the existing condition. The

dark-green part indicates an area of (wet) ocean cells, and the light-white part indicates an area

of (dry) land cells. Also shown in this figure is the water depth contour associated with the 10-

6-2

year tidal stage. The water depth under the 10-year tidal stage was used in the STWAVE

simulation for wave propagation in the South Basin and the project area. A 1 0-year tidal stage

of 6.1 feet NGVD (approximately 2.68 meters NAVD88) that was estimated for Hunters Point

(USACE, 1984) was used in this analysis.

Part of the Cartesian grid and the associated water depth contour at the project area is shown in

Figure 6-5 for the project condition. It is noted that the proposed two islands will be inundated

under the 1 0-year tidal stage. Figure 6-5 also shows the nine locations at which potential

erosion during extreme storm events would be estimated in Section 6.3.

6.2.2 Existing Conditions

The simulated wave heights in the South Basin and Yosemite Canal is shown in Figures 6-6 to

6-8 for the 50-year, 10-year and 1-year offshore wave conditions, respectively. It seen that the

wave height generally decreases as propagating from offshore to the basin. For the 50-year

wave, the wave height ranges from 1.1 to 1.4 meters in the outer South Basin, 0.5 to 1.0 meter

sin the wave-exposure zone and less than 0.3 meters in the wave-shadow zone at inner South

Basin, and decreases to lower than 0.4 meters in the Yosemite Canal. It is also noted that the

wave height in the inner South Basin and Yosemite Canal does not show apparent difference

between the 50-year and the 1 0-year offshore wave conditions. This is because waves in the

South Basin and Yosemite Canal are already broken when big waves propagating from offshore

during extreme storm events. The wave climate of broken waves mainly depends on the local

water depth and exposure condition instead of offshore wave height. Compared to the 50-year

and 1 0-year waves, the 1-year wave is generally lower. However, the difference is small in the

Yosemite Canal. The relatively milder wave climate in the inner South Basin and Yosemite

Canal partially attributes to the wave breaking process, and partially attributes to the contracted

cross-section in the middle of the South Basin.

6.2.3 Project Conditions

Figures 6-9 to 6-11 show the predicted wave heights in the project area for 50-year, 1 0-year

and 1-year offshore wave events under the 1 0-year tidal stage. Negligible difference is shown

in the predicted wave heights between the 50-year and 1 0-year offshore wave events. This

suggests that the predicted wave climate for the 50-year or for the 1 0-year offshore wave event

may also represents the worst wave condition that would occur in the project area under the 1 0-

6-3

year tide stage. The wave height that will occur in the project area during extreme storm events

was estimated to range from 0.6 meters in the canal mouth area to less than 0.1 meters in the

upper canal and in the NW embayment. Higher waves were predicted in the canal mouth

because this area is directly exposed to the approaching path of incoming offshore waves and

has relatively deeper water depth.

Because the proposed island will be inundated under the 1 0-year tidal stage, the SE

embayment will also be directly exposed to the incoming waves. As a result, 0.3-meter waves

will generally exist in the tidal channel with a water depth of approximately 0.7 meters under the

1 0-year tidal stage. However, the island will be exposed above the water as water level

decreases, and a much milder wave climates will exist behind the island in the SE embayment

because of the sheltering effect of the island. While the wave height was estimated to be 0.3 to

0.4 meters in the canal next to the NE embayment, small waves of 0.1 to 0.2 meters high were

estimated for the shallow inner part of the NE embayment as a result of the worse wave

exposure condition. Small waves were also predicted in the upper port of the canal and in the

entire NW embayment. Waves in these areas will be lower than 0.1 meters.

6.3 Assessment of Wave-Induced Bed Erosion for Project Conditions

The potential for bed erosion that will be induced by wave particle velocities during extreme

storm events were estimated at nine representative locations as shown in Figure 6-5. A mean

duration of 11.4 hours was estimated by Battelle et al (2005) for the storm events in the South

Basin, and the storm duration used in this analysis was 12 hours. Wave conditions in the

project area depend on local water depth for given offshore wave condition, and the local water

depth will fluctuate with oscillating tide levels during a storm event. Therefore, a series of wave

climates were predicted for every half hour within the 12-hour storm duration for both the 50-

year and the 1 0-year storm events. The water level fluctuations within the 12 hours were

represented by a synthetic series of tidal levels as shown in Figures 6-12 and 6-13. The

highest tide equals to the 10-year tidal stage (approximately 2.68 meters NAVD88), and the

lowest tide equals to the lowest observed water level at Hunters Point (-0.57 meters NAVD88).

The potential for wave-induced bed erosion was calculated based on an empirical relation

determined from a Sedflume analysis for the bed material of the South Basin (Battelle et al,

2005), which links the bed erosion rate to the bottom shear stress. The instantaneous bottom

6-4

shear stress is a function of the instantaneous wave particle velocity at the bottom, which was

determined based on the linear wave theory for given local water depth, wave height and wave

period. The local wave condition was predicted using STWAVE.

Figure 6-12 shows the synthetic tidal level every half hour within the 12-hour storm duration, the

wave-induced bed erosion potential predicted for every half hour, and the cumulative erosion

potential during the 12-hour duration for the 50-year wave event at location E6. Figure 6-13

shows the results at Location E9. The results indicate that the wave-induced erosion depth

depends on water depth (or tidal level) during a storm. Because location E6 is approximately 2

meters lower than location E9, E6 will subject to a longer duration of wave motion and resulting

wave-induced erosion.

The predicted total bed erosion potentials for the nine representative locations in the project

area are summarized in Table 6-2 for the 1 0-year to 50-year offshore wave events. As a result

of the mild wave condition, erosion will not likely be induced by wave motions in the NW (E1)

and inner NE (82) embayments, or in the middle (E5) and upper canal (E4). The mouth of the

canal (E6) will suffer the most serious erosion. The outer NE embayment (E3) will also be

eroded as much as 19 centimeters during storm events. Wave-induced erosion will generally

occur in the SE embayment (E7 to E9). Although the erosion duration in the relatively high NE

embayment is only 4 hours (see Figure 6-13) during the 12-hour storm event, the erosion depth

ranges from 5 centimeters to 16 centimeters.

It should point out that the estimated erosion potential induced by waves only considered the

erosion caused by the wave particle velocity that is high enough to induce a bottom shear stress

exceeding the critical shear stress for erosion. However, the wave particle velocity oscillates

with time as water surface elevation fluctuates in each wave period. As a result, sediment

deposition will occur when the wave particle velocity is low and the resulting bottom shear stress

is less than the critical shear stress for deposition. The sediment deposition will compensate

part of the erosion that occurs during the high wave particle velocities. Therefore, the actual

erosion during the extreme storm events will be less than the estimated erosion potential.

6-5

Table 6-2 Potential for bed Erosion Induced by the 10-Year to 50-Year Wave Events

Location Erosion depth (em)

E1 0

E2 0

E3 10 -19

E4 0

E5 0

E6 16-27

E7 5-8

E8 7-12

E9 10-16

6-6

7.0 REFERENCES

Ackers, P. and White, W. R., 1973. "Sediment Transport: New Approach and Analysis", Journal

of the Hydraulics Division, ASCE, No. HY11.

Ariathurai, R., MacArthur, R. C. and Krone, R. B., 1977. "Mathematical Model of Estuarial

Sediment Transport", Technical Report D-77 -12, US Army Engineer Waterways Experiment

Station, Vicksburg, Mississippi.

Buchanan, P.A., and Schoellhamer, D.H., 1995, Summary of suspended-solids concentration

data, central and south San Francisco Bay, California, water years 1992 and 1993: U.S.

Geological Survey Open-File Report 94-543, 15 p.

Buchanan, P.A., Schoellhamer, D.H., and Sheipline, R.C., 1996, Summary of suspended-solids

concentration data, San Francisco Bay, California, water year 1994: U.S. Geological Survey

Open-File Report 95-776, 48 p.


data, San Francisco Bay, California, water year 1995: U.S. Geological Survey Open-File Report

96-591' 40 p.


data in San Francisco Bay, California, water year 1996: U.S. Geological Survey Open-File

Report 98-175, 59 p.


data in San Francisco Bay, California, water year 1997: U.S. Geological Survey Open-File

Report 99-189, 52 p.

Buchanan, P.A. and Ruhl, C.A., 2001. Summary of suspended-sediment concentration

Data, San Francisco Bay, California, water year 1999, Open-File Report 01-100.

Buchanan, P.A. and Ganju, N.K., 2002. Summary of suspended-sediment concentration data,

San Francisco Bay, California, water year 2000, Open-File Report 02-146.

7-7


San Francisco Bay, California, Water Year 2001, Open-File Report 03-312, ONLINE ONLY


San Francisco Bay, California, Water Year 2002, Open-File Report 2004-1219.

Cheng, N.S., 1997. "Simplified Settling Velocity Formula for Sediment Particle", Journal of

Hydraulic engineering, Vol. 123, No.2.

Norton, W. R. and King I. P., 1977. "Operating Instructions for the Computer Program RMA2-

2V", Resource Management Associates, Lafayette, CA.

Partheniades, E, 1965. "Erosion and deposition of cohesive soils ", Journal of the Hydraulic

Division, Proceedings of the American Society of Civil Engineers, Vol. 91, Ho.HY1.

Smith, J. M., Sherlock, A.R. and Resio, D.T., 2001. STWAVE: Steady-State Spectral Wave

Model, Users Manual for STWAVE Version 3.0. US Army Corps of Engineers, Engineering

Research and Development Center, p66.

U.S. Army Corps of Engineers-San Francisco District, 1984. "San Francisco Bay Tidal Stage

vs. Frequency Study''.

7-8

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Surveyed Bathmetry at Yosemite Canal and South Basin

..... ______________________ -! tJ:Q]2.~~ ..... ___ .. Figure 2-1

G1 to G2: C1 : S1 to S3: L 1 to L6:

Locations of Outer and Inner Water Level Gages Location of Aquadopp Current Meter Locations of Three Soil Samples Locations of Six Output Time Series of Flow Conditions Shown in Figures 4-5, 4-11 , 4-14 and 4-18

Locations of Field Data Collections and Outputed Time Series of Simulated Flow Conditions

NOBLE C:OIII'I.U,8t& 18C

Figure 2-3

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Day starting from Sept. 25, 2003 12 14 16 18

Measured Water Level Compared to NOAA Predicted Tide at Hunters Point

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Figure 2-4

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0 2 4 6 8 10 12 14 16 18 Day starting from Sept. 25, 2003

Measured Tidal Current Velocities

NOBLE I ...._ __________________________ ~, co•••u••t& uc 111----..1

Figure 2-5

Finite Element Mesh (Existing Condition, Whole Domain)

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-ctl ~

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...................................................................................................................................... ~1 ~~~~~~ II I

Figure 3-4

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6 05

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10 12 14 16

Simulated Tidal Stage and Currents Compared to Measurement

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Figure 3-5

Simulated Water Depth During a low Tide (Existing Condition, Whole Domain)

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Figure 4-1

Simulated Water Depth During a High Tide (Existing Condition, Whole Domain)

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Figure 4-2

Simulated Water Depth During a High Tide (Existing Condition, Project Area)

Figure 4-4 I

4 3.5

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0.5 0

0 2 3 4

4 3.5

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5 6 7 8 9 10 11 12 13 14 15

5 6 7 8 9 10 11 12 13 14 15

5 6 7 8 9 10 11 12 13 14 15

5 6 7 8 g 10 11 12 13 14 15

5 6 7 8 9 10 11 12 13 14 15

5 6 7 8 9 10 11 12 13 14 15 Day stratin g from Sept. 25, 2003

Simulated Time Series of Warer Depth for Existing Condition

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Figure 4-7

Simulated Ebb Currents (Existing Condition, Whole Domain)

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Simulated Flood Currents (Existing Condition, Project Area)

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Figure 4-9

Ci ~ <(

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5 6 7 8 9 10 11 12 13 14 15

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5 6 7 8 9 10 11 12 13 14 15

5 6 7 8 9 10 11 12 13 14 15

5 6 7 8 g 10 11 12 13 14 15

5 6 7 8 9 10 11 12 13 14 15

5 6 7 8 9 10 11 12 13 14 15 Day strating from Sept. 25, 2003

Simulated Time Series of Current Speed for Existing Condition

L.--------------------------------------------------------~~~~~.~~11---------_. Figure 4-11

Predicted Water Depth During a Low Tide (Project Condition, Project Area)

NOBLE I .. llllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll!lllll!lllllllllllllllll!lllllllll~~ COIIGitt•t& IIC lllllllllllllllllllllllllllrl

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Predicted Water Depth During a High Tide (Project Condition, Project Area)

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Figure 4-13

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0 2 3 4

4 3.5

E' 3 ~2.5 ..c: 2 ..... g- 1.5 0 1

0.5 0

0 2 3 4

5 6 7 8 9 10 11 12 13 14 15

5 6 7 8 9 10 11 12 13 14 15

5 6 7 8 9 10 11 12 13 14 15

5 6 7 8 g 10 11 12 13 14 15

5 6 7 8 9 10 11 12 13 14 15

5 6 7 8 9 10 11 12 13 14 15 Day strati ng from Sept. 25 , 2003

Predicted Time Series of Warer Depth for Project Condition

NOBLE..,.._ _ ___. C'OI I VU.I I J I. II C'

Figure 4-14

L() ..--

>-- I uco '<::t

c: C1) C1) .!:: ~ :J"'4, ::J tT 0 .2' ~C1) LL LL"O' c: a.. oa.. :;:;C' co 0 -c ·-c:~ :::s""C c: c:

- 0 -cU Q)-0 (.) :C·~

C1) 0 a.. a.. a..e:.

<D ...--- I

nJ ""'" Q) Q) I..

1/) <( .._ - ::::J

t: - 0'> Q) u u:: I.. Q) I.. "0' :::l

(.) I.. D.. ~; "0

~~ 0 t: 0 0 IIl: U:::E o: "0"0 Q) t: z: - 0 -~ (.) "0 -Q) u I.. Q)

D.. "0' I..

D.. -

1"--...--I - -.::t ca

(J) Cl) .... I.... < :::J (/) 0) -- i.L c (J

Cl) Cl) .... ·-. .... 0 :::s .... r,£1; (.)D..

..0 c ~ ..

..0 0 cr:l: w ... o: _,

'0:0 ; Cl) c z: t) 0 ; ; ·- (.) '0 Cl) -" " " .... (J

D.. Cl) J

'0' .... D..

~

~

~0. 15

~ ~ 0. 1 CD > 0.05

0.2

~0. 15

~ ~ 0.1 CD > 0.05

0 0

~0. 15 (/J

~ 0.1 CD > 0.05

..

2

!

... ••

. . . . . ..

2

3 4 5 6

! ! I

.. ·: ..

v ~ 3 4 5 6

7 8 9 10 11 12 13 14 15

ocation 2 I ! ! !

·•···· ' ......... . ... ., ..... I

.... . ... --· ... ··· I:·· ..

! ~ I Wv 'V II v 7 8 9 10 11 12 13 14 15

o UL~LU~~~~~~~~~~~~~~~~~~~~~~~~~~~~

0 2 3 4

~ 0. 15

~ ~ 0. 1 CD > 0.05

2 3 4

0.2

~0.1 5

~ ~ 0.1 a; > 0.05

2 3 4

0.2

~0.1 5 (/J

~ 0.1 CD > 0.05

2 3 4

5 6 7 8 9 10 11 12 13 14 15

5 6 7 8 9 10 11 12 13 14 15

5 6 7 8 9 10 11 12 13 14 15

5 6 7 8 9 10 11 12 13 14 15 Day strating from Sept. 25, 2003

Predicted Time Series of Current Speed for Project Condition

Figure 4-18

Simulated Bed Change (Existing Condition, Whole Domain)

~------------------------------~NOBLE 1~----~ Cf01ff1.7AI7 .. UCJ

Figure 5-1

"'C Cl) CJ ::::J

"'C c::

..... CJ Cl)

'0' ~

a.. 1/) c: 1/) 0 ~;e ..... -c tn c: ~ 0 nl(.)

~C) tn c:: .. E 1/) 0 ')( ::::w o-COJ!l "'C c: ~ ~ ~ 5 eu ·- "'C tn 0

0 LL

-ns ~Q)

..0 ...

,~ Q) u u Q)

::::J "0' , ... ca.. 1/) s:: 1/) 0 Q) a...;E -, en s:: ... 0 mu ..CO) en s:: E+" 1/) .s >< -w o_ m 1/) ,_ Q) s::

- Q) .!!! t::: ::::J ::::J eu ·- ..0 en..c

w

o: z:

-C'l'l ~

Q)<( 0)s::: 0 C'l'l·~ .c 0 uQ: "0 ~ Q) c

r::c 0 -cE Q)"C - c -~ 0 -cU ~

D.. ~ ·o lo.

D.. -

L!) I

L!)

~ :::J 0)

u::

c:.o I - L() ca

~~ Q) '-.C<( ::J

"0 .... CJ) Cl) (J i.L (J .!, ::J 0

"0 "-cO.. ~; 1/) c ~= 1/) 0 c:o~ Cl) E "- o: .... "0 t/) c z: "- 0 ca (.) Cl) J: .... t/)

(J Cl)

E ..... 0

0 "-.... a. --0 1/) al .... "0

c Cl)

Cl) "-.... "--~ ::J "0 (.) CI)"O "- 0 0.. 0

LL.

,..... I - LO cu

~~ (J) ..c<C I....

:::1 "'0 - 0> Q) (.) u:: (.) Q) ::I "0' "'0 c 1..

0. ~; 1/) c ......::l: 1/) Q) 0 cu: 1.. ;e - o: en "'0 1.. c ZE cu 0 Q) ()

.s:::: -en (.)

E Q)

"0' 0 1.. -0. -0 -m 1/) -"'0 c Q) Q) - 1.. (.) 1..

"'0 ::I

Q) ()

'-..c O...c

w

NW

NWW 292.5

West 270

247.5 sww

315

225

sw

NNW

337.5

···' · ••• • •

202.5

ssw

North

0

. 30%.

"20% . .

I. 10% :· ..

•• ••

• •• I . .· ~o%

.zo%·

180

South

NNE

22.5

• • • •. . ...

••

157.5

SSE

Note: Derived from hourly wind data measured at San Francisco International Airport from 1948 to 2004

NE 45

67.5 NEE

90 East

112.5 SEE

135

SE

Occurrence Frequency of Wind Directions

II NO BLEil ---------------------------·1111 COIIVI.tAJrl, IJf: ~~~~------..

Figure 6-1

~ .. ':"'.::-;;-;-

~H--"- _:_1, '1

- -'1; -'· "'

•·· .?-:-

Wind Fetches at Bayside of South Basin

~----------------------------~1 NOBLE OtlltUJJtl IJC

Figure 6-2

1.6

1.5 -; - . - .....

1.4 _,. 1.3

~ 1.2 g :E Cl

"Qj 1 .1 .s:::. a.l > t'U

3: 1.0

0.9

0.8

0.7

0.6

10

Return period (year)

,_,,.,. .,..,. ,.,. I

~Data

- Fitted Weibull Distribution

,.,.,.,.

- - 90% Confidence Internal Bounds

100

Hindcasted Wave Height at Bayside of South Basin

NOBLE I COJIVLt.lltl. (JC 111--------..

Figure 6-3

~---------------------------------------------------------,~ J: -a.-<1> c: c '(ij

"" E ~ 0 cue 3: <I> "Cc: 0 CUJ: "03: 'i: c C) 0 c::E CU"C ·- c: 1/) 0 ~u cu 01 u c: "C:;:;

<I> .!!! - >< <~>w '8-~

I

<D

~ :::1 0)

LL

Note: S1 to S9 show locations for evaluation of poential scouring during extreme events Modeled Cartesian Grid and Water Depth


------------------------------------------------------------------~~~>----~: ~ ~ ~-0 c

..s::::: ·-1/j ctl = E 0 0 '-0 ctl ~ ~> 0 ,..s::::: ~3: '- c 0 0 ..... ·-..... :!::

..s:::::"C Ole

"Ci) 0 ::I:O ~ en > c ctl:;o

3: -~ "C >< ~w .... -ctl :I E tn

:::J 0)

u:::

Q)

> :: ~ 0-.s::. ns ~ ~ o<t -'- CJ ns a> Q) ·-. >- 0 I '-ca.

I() ~

'- s::::: 0 0 -... l::C .2' g Q)(.) :::t:_ Q) CJ > Q) ns ·-. 3: e a. "'0-Q)

t) "'0 Q) '-a.

Predicted Wave Height for 10-Year Offshore Wave (Project Condition, Project Area)

NOBLE I ...................................................................................................................................... ~~ COIIf,fllf& IIC 111 .............. ...

Figure 6-10

Predicted Wave Height for 1-Year Offshore Wave (Project Condition, Project Area)

NOBLE I .. ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!ll!~~ COIIILIAit' IIC lllll!ll!ll!ll!ll!ll!ll!ll!rl

Figure 6-11

3

co 2.5 co 0 2 > <(

1.5 z E 1 -> OJ 0.5 05 (6 0 "'0

f= -0 .5

.. ........ ... .. .. .

... .. ;. . ... ..; .. . .

... ~. - . . .

.. ... ......... .... ....... ; ....... .

- 1 L---~--~---L--~--~----L---~ __ _L __ _L __ ~ ____ L___j

0 1 2 3 4 5 6 7 Time (hour)

g 10 11 12

4----,---.----r---.---,----,---,---~~---.--~--~~~

3.5 ........... E 3 (.) -_c 2.5 ..... c.. ~ 2

§ 1.5 -~ w 1

0.5

..... ...... . ;.

... .. ... ... .. .. .. ... .. ;

o L-~~~~~~~_L_L_L __ _i __ _J ____ L_L_L_L_~~J_~~

0 1 2 3

... ... .. ; ... ...... ... ~- . . .

1 2 3

Note: Bottom elevation at location E6 is approximately 0.0 meters NAVD88

4

4

5 6 7 Time (hour)

. .. ; . ...... ... .. • .. .

5 6 7 Time (hour)

8

8

9 10 11 12

. . . . . . -- . . . . ; . .

9 10 11 12

Wave-Induced Erosion at Location E6 During 50-Year Wave Event

NOBLE COJIW&.tllf& IIC ..,.. ____ ..

Figure 6-12

~ 2.5 .. .. 00 0 2 > <J:: z 1.5

§. 1

::> <II 0.5 as (6 0 "0

f.= -0 .5

... .. . : . ..... . .. . ... : .

... .. .... ... ;

-1 ~--~--~--~--~--~--~--~--_L __ _L __ _L __ _L __ _j

0 1 2 3 4 8 9 10 11 5 6 7 Time (hour)

12

4 ~--,---,---,---~--,---,---,---,---~--~--~--~

3.5 ,..... E 3 0 -_c 2.5 +--0.

~ 2

§ 1.5 -~

w 1

. . .... . . ... ..... ... . .. : . ... .. .. .. . <·

. .. .. ... ... : ..

: : ····· ···•·\· ····· ··· ··· ··· ··· ···:··· ··········:··· ·· ··· ·· ··:····· ···· ···· !· ··

0 .5

o ~~~L_L_~L_~L_~L_~L_~L_~L_~L_~~~~~

0 1 2

... ... ........ ......... .... ...... ; .. ..

8 9 10 11 3 4 5 6 7 12

. . . . · ·· ·· ···· ·<· ····· ········:·· ·

Note: Bottom elevation at location E9 is approximately 2.0 meters NAVD88

Time (hour)

: : .... ..... ......... ...... .. · ·: •

5 6 7 Time (hour)

8

. . ...... . .. ... .....

9 10

. . ; ..

11 12

Wave-Induced Erosion at Location E9 During 50-Year Wave Event

Figure 6-13

hydrodynamic modeling, wave analysis & sedimentation

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