Chino Basin Optimum Basin Management Program

The Chino Basin is a large, adjudicated groundwater basin located in southern California. In 1998, a court order called for Chino Basin Watermaster (Watermaster) to develop an Optimum Basin Management Program (OBMP). Watermaster, given a two year time period, convened a process that was successful in the development of the OBMP, which is currently being implemented at an ultimate cost of over $400 million. One of the principle goals of the OBMP was to develop the maximum yield of the Chino Basin for the benefit of the basin's producers. This is being accomplished by increasing the recharge of local and supplemental water in the forebay areas, and by modifying pumping patterns in areas of historic discharge in an attempt to minimize discharge, induce more recharge, yet preserve sensitive ecological habitat and downstream water rights. Under construction are 21 groundwater recharge basins that will accept imported, recycled, and storm waters, and the second of two groundwater extraction and desalting facilities. These desalting facilities, when completed, will convert groundwater contaminated by 100 years of irrigated agriculture and dairy operations to 20 mgd of high-quality water for municipal supply. Watermaster and the Inland Empire Utilities Agency (IEUA) have been conducting monitoring and modeling investigations to guide the yield maximization programs. The programs and investigations have suggested that lowering the groundwater storage by about 200,000 acre-ft through a controlled overdraft, along with the expansion of the extraction and desalting system to 40 mgd, are necessary to maximize the yield of the basin.