The C2VSimFG model elements are grouped into 21 subregions to facilitate data entry and reporting of model results. The subregion can be further grouped by: subregion 1 to 7 representing the Sacramento Valley, subregion 10 to 13 representing the San Joaquin River, subregion 14 to 21 representing the Tulare Lake Basin, and subregion 8 and 9 representing the streams tributary to the Sacramento - San Joaquin Delta and the Delta, respectively. The subregions are based on the portions of the Depletion Study Areas (DSAs) within the model boundary. The DSA's were originally developed by the Department of Water Resources' Division of Planning. The areas calculated for this data using the WGS 1984 Web Mercator projection may not reflect the actual areas used in the C2VSimFG model.