Some 2000-3000 largely agricultural, unscreened and unregulated water diversions currently operate in the Delta. A 1993 U.S. Fish and Wildlife Service listing of the delta smelt estimated that local in-Delta diverters export up to 5,000 cubic feet per second (cfs) from the Delta - or almost half as much as the combined federal and state pumping plants maximum export rate of up to 11,000 cfs. The number of agricultural in-Delta diversions has expanded over the past decade and therefore, the rate of unscreened and unregulated diversions has likely increased. Unscreened in-Delta diversions impact the delta smelt through entrainment and hydrodynamic influence. Moreover, State and federal regulators have expended little or no effort to date to regulate or monitor these diversions in order to slow the decline of endangered species.
In addition to the State and federal pumping operations, a number of municipalities operate diversions, including pumps, to serve municipal and industrial users in the Delta and Northern California, including the Bay Area. Together, these diversions directly impact the quantity and quality of water available for fisheries and the ecosystem.