SALTON SEA A linked hydrodynamic and water quality model for the Salton Sea Eu Gene Chung Æ S. Geoffrey Schladow Æ Joaquim Perez-Losada Æ Dale M. Robertson Ó Springer Science+Business Media B.V. 2008 Abstract A linked hydrodynamic and water quality model was developed and applied to the Salton Sea. The hydrodynamic component is based on the one- dimensional numerical model, DLM. The water quality model is based on a new conceptual model for nutrient cycling in the Sea, and simulates temperature, total suspended sediment concentration, nutrient concentrations, including PO 3 4 ; NO 1 3 and NH þ1 4 ; DO concentration and chlorophyll a concen- tration as functions of depth and time. Existing water temperature data from 1997 were used to verify that the model could accurately represent the onset and breakup of thermal stratification. 1999 is the only year with a near-complete dataset for water quality variables for the Salton Sea. The linked hydrody- namic and water quality model was run for 1999, and by adjustment of rate coefficients and other water quality parameters, a good match with the data was obtained. In this article, the model is fully described and the model results for reductions in external phosphorus load on chlorophyll a distribution are presented. Keywords Restoration  Nutrients  Sediment resuspension  Internal loading Introduction The Salton Sea is a highly saline, terminal lake, located in the southeastern desert of California. The Sea serves as a repository for agricultural drain water from the Coachella and Imperial Valleys of California and the Mexicali Valley of Mexico. It constitutes the largest body of water in the state, encompassing 963 km 2 , with a maximum depth of 15.5 m, a maximum length and width of 56 and 26 km respectively, a maximum water elevation of -69 m mean sea level (MSL) and a salinity of approximately 48,000 mg l -1 (State of California Resources Agency, 2006). Its total volume is about 9.25 9 10 9 m 3 (Cook et al., 2002). In its present state, the Salton Sea is a highly eutrophic lake, Guest editor: S. H. Hurlbert The Salton Sea Centennial Symposium. Proceedings of a Symposium Celebrating a Century of Symbiosis Among Agriculture, Wildlife and People, 1905–2005, held in San Diego, California, USA, March 2005 E. G. Chung  S. G. Schladow Department of Civil and Environmental Engineering, University of California, Davis, CA 95616, USA S. G. Schladow (&) Tahoe Environmental Research Center, University of California, Davis, CA 95616, USA e-mail: gschladow@ucdavis.edu J. Perez-Losada Departament of Physics, University of Girona, Girona 17071, Spain D. M. Robertson U.S. Geological Survey, Middleton, WI 53562, USA 123 Hydrobiologia (2008) 604:57–75 DOI 10.1007/s10750-008-9311-6