Scientific Investigations Report 2007–5005
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2007–5005
PONDCALC—A Tool to Estimate Discharge from the Alviso Salt Ponds, California
Prepared in cooperation with the U.S. Fish and Wildlife Service
By Gregory G. Shellenbarger, David H. Schoellhamer, and Megan A. Lionberger
Table of Contents
Conversion
Factors and Abbreviations
Abstract
Introduction
Pond
Discharge Equations
Pond
Discharge Calculator PONDCALC
Summary
References
Cited
Appendix
Figures
Figure
1. Alviso salt pond study area as part of the Alviso Salt Pond Complex, South
San Francisco Bay, California. Discharge ponds relevant to this report are
labeled.
Figure
2. Schematic diagram of culvert discharge structure used in the Alviso salt
ponds, California. The water-surface elevation in the slough changes with
the tide. The trash rack prevents debris in the sloughs from blocking the
hinged flap gate.
Figure
3. Schematic diagram of weir box structure used in Alviso salt ponds, California.
HW represents the height of the pond
water surface above the weir boards, b is the width of the weir boards, and
y is the height of the weir boards above the pond bottom.
Figure
4. Sled holding the acoustic Doppler current profiler used to measure discharge
from pond A3W, Alviso salt ponds, California. Note culvert discharge structures
with the red screw gates in the background.
Figure
5. Measured and predicted discharge from pond A3W compared to head (h1-h2),
Alviso salt ponds, California. Predicted discharge is calculated from equation
1 with the energy loss term, KL, calculated from equations 4 and 5.
Figure
6. Culvert loss coefficient, KL, related to head in pond A3W, Alviso salt
ponds, California. The two curve fits were determined by least squares regression.
The dotted vertical line shows the transition between the two regressions.
Figure
7. Estimate of the minimum error associated with the prediction of flow rate
as compared to head in pond A3W. The minimum error estimate is the percent
error associated with the prediction of Q from the estimates of KL, where
Qp is the predicted flow rate and Qm is the measured flow rate. Q is calculated
from eq. 1. For heads above 0.25 ft, the predicted flow rate is within 20 percent
of the measured flow rate.
Tables
Table
1. Discharge structures for the study salt ponds in the Alviso Salt Pond Complex,
South San Francisco Bay, California.
This report is available online in Portable Document Format (PDF). If
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Send questions or comments about this report to the author, Greg Shellenbarger, (916) 278-3191.
For more information about USGS activities in California, visit the USGS
California Water Science Center home page.
U.S.
Department of the Interior | U.S. Geological Survey
