Salt-Pond Box Model (SPOOM) and Its Application to the Napa-Sonoma Salt Ponds, San Francisco Bay, California

By Megan L. Lionberger, David H. Schoellhamer, Paul A. Buchanan, and Scott Meyer



Water–Resources Investigations Report 03-4199

Sacramento, California 2004

Complete accessible text of report (594 KB PDF)

Supporting model data.(excel file 1MB)

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A box model to simulate water volume and salinity of a salt pond has been developed by the U.S. Geological Survey to obtain water and salinity budgets. The model, SPOOM, uses the principle of conservation of mass to calculate daily pond volume and salinity and includes a salt crystallization and dissolution algorithm. Model inputs include precipitation, evaporation, infiltration, and water transfers. Salinity and water-surface-elevation data were collected monthly in the Napa-Sonoma Salt-Pond Complex from February 1999 through September 2001 and were used to calibrate and validate the model. The months when water transfers occurred were known but the magnitudes were unknown, so the magnitudes of water transfers were adjusted in the model to calibrate simulated pond volumes to measured pond volumes for three ponds. Modeled salinity was then compared with measured salinity, which remained a free parameter, in order to validate the model. Comparison showed good correlation between modeled and measured salinity. Deviations can be attributed to lack of water-transfer information. Water and salinity budgets obtained through modeling will be used to help interpret ecological data from the ponds. This model has been formulated to be applicable to the Napa-Sonoma salt ponds, but can be applied to other salt ponds.




Purpose and Scope


Description of the Study Area

Data Collection

Model Description



Salt Crystallization and Dissolution

Water Transfers

Pond Geometry

Analytic Test Cases

Application of the Model to the Napa-Sonoma Salt Ponds




Water Transfers

Pond Geometry

Model Calibration and Validation

Pond 3 Calibration and Validation

Pond 4 Calibration and Validation

Sensitivity Analysis of Water Transfers for Ponds 3 and 4

Pond 7 Calibration and Validation


Other Model Applications

Summary and Conclusions

References Cited

Appendix. Sodium chloride prime specific gravity, salinity, and density data

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Water Resources of California

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