Water Quality Controls on Imperial Valley Drainage

The Federal Water Pollution Control Act (FWPCA) mandates the development of best management practices for drainage flows from irrigated lands. Data on existing irrigation and drainage practices in California's Imperial Valley have been collected and analyzed. These data indicate that the dissolved salts in the drainage water originate in the imported irrigation water, and that the drainage water's salinity is inversely related to irrigation efficiency. Located in a closed basin, the drainage in the Imperial Valley Flows into the basin's sump, the Salton Sea, and continued crop production is dependent upon the maintenance of the Sea as a sump for the Valley. For the Imperial Valley, Salinity Control of the drainage flows should not be an objective of a best management practices plan.