USGS


Hydrodynamic and Suspended-Solids Concentration
Measurements in Suisun Bay, California, 1995

By Jay I. Cuetara, Jon R. Burau, and David H. Schoellhamer

 

U.S. GEOLOGICAL SURVEY

Water Resources Investigation Report 01-4086

Sacramento, California 2001


Main Text of report (1.8 MB PDF)
Appendix_A-G (2.5 MB PDF)
Appendix_H-N (1.2 MB PDF)
Appendix_O-V (1.9 MB PDF)
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ABSTRACT

Sea level, current velocity, water temperature, salinity (computed from conductivity and temperature), and suspended-solids data collected in Suisun Bay, California, from May 30, 1995, through October 27, 1995, by the U.S. Geological Survey are documented in this report. Data were collected concurrently at 21 sites. Various parameters were measured at each site. Velocity-profile data were collected at 6 sites, single-point velocity measurements were made at 9 sites, salinity data were collected at 20 sites, and suspended-solids concentrations were measured at 10 sites. Sea-level and velocity data are presented in three forms; harmonic analysis results; time-series plots (sea level, current speed, and current direction versus time); and time-series plots of low-pass-filtered time series. Temperature, salinity, and suspended-solids data are presented as plots of raw and low-pass-filtered time series.

The velocity and salinity data presented in this report document a period when the residual current patterns and salt field were transitioning from a freshwater-inflow-dominated condition towards a quasi steady-state summer condition when density-driven circulation and tidal nonlinearities became relatively more important as long-term transport mechanisms. Sacramento-San Joaquin River Delta outflow was high prior to and during this study, so the tidally averaged salinities were abnormally low for this time of year. For example, the tidally averaged salinities varied from 0-12 at Martinez, the western border of Suisun Bay, to a maximum of 2 at Mallard Island, the eastern border of Suisun Bay.

Even though salinities increased overall in Suisun Bay during the study period, the near-bed residual currents primarily were directed seaward. Therefore, salinity intrusion through Suisun Bay towards the Delta primarily was accomplished in the absence of the tidally averaged, two-layer flow known as gravitational circulation where, by definition, the net currents are landward at the bed. The Folsom Dam spillway gate failure on July 17, 1995, was analyzed to determine the effect on the hydrodynamics of Suisun Bay. The peak flow of the American River reached roughly 1,000 cubic meters per second as a result of the failure, which is relatively small. This was roughly 15 percent of the approximate 7,000 cubic meters per second tidal flows that occur daily in Suisun Bay and was likely attenuated greatly. Based on analysis of tidally averaged near-bed salinity and depth-averaged currents after the failure, the effect was essentially nonexistent and is indistinguishable from the natural variability.

CONTENTS

Abstract

Introduction

Purpose and Scope

Study Area

Geographic Setting

Tides

Currents

Hydrologic Conditions

Meteorological Conditions

Sediment

Acknowledgments

Findings

Tidal Timescale Variability

Currents

Salinity

Residual Timescale Variability

Currents

Salinity

Affect of Folsom Dam Spillway Gate Failure on Suisun Bay Hydrodynamics

Sediment Transport

Summary

References Cited

Appendix A: Data Reduction Details and Data Presentation

Data Reduction Details

Acoustic Doppler Current Profiler Data

Sea-Level Data

Salinity Data

Conductivity-Temperature Sensors

Conductivity-Temperature-Depth-Optical Backscatterance Sensors

Salinity Computation

Suspended-Solids Concentration Computation

File Formats

Time-Series File Format

Acoustic Doppler Current Profiler File Format

Data Presentation

Plotting of Oceanographic Data

Low-Pass Filter

Harmonic Analysis

Appendix B--Station BEN

Appendix C--Station BULLS

Appendix D--Station CARQ

Appendix E--Station MET

Appendix F--Station CUT

Appendix G--Station GARN

Appendix H--Station GARNW

Appendix I--Station GC

Appendix J--Station GDOL

Appendix K--Station GS

Appendix L--Station HC

Appendix M--Station HDOL

Appendix N--Station HS

Appendix O--Station MAL

Appendix P--Station MART

Appendix Q--Station MID

Appendix R--Station MOTH

Appendix S--Station RYER

Appendix T--Station RYERE

Appendix U--Station SPOON

Appendix V--Station WICK


Water Resources of California


U.S. Department of the Interior, U.S. Geological Survey
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