Perhaps the most controlling single element in California water rights is the California Water Project (operated by the state Department of Water Resources) . The California State Water Project is a water storage and delivery system of reservoirs, aqueducts, powerplants and pumping plants. Its main purpose is to store water and distribute it to 29 urban and agricultural water suppliers in Northern California, the San Francisco Bay Area, the San Joaquin Valley, and Southern California. Of total Project deliveries, approximately 40 percent is used to irrigate farmland, and 60 percent goes to meet the needs of the State's growing population.
The Project makes deliveries to two-thirds of California's population. It is maintained and operated by the California Department of Water Resources. The Project is also operated to improve water quality in the Delta, control Feather River flood waters, provide recreation, and enhance fish and wildlife.
History -- In 1960, California voters approved the $1.75 billion bond issue to begin building the State Water Project. The Project was designed and constructed by the Department of Water Resources. By 1973, the initial facilites were completed and water delivery to southern California began.
Size -- Today, the Project includes 29 storage facilities, reservoirs and lakes; 18 pumping plants; 4 pumping-generating plants; 5 hydroelectric power plants; and about 660 miles of aqueducts and pipelines. The Project provides supplemental water to approximately 20 million Californians and about 1.2 million acres of farmland.

Water marketing of some kind of other has long been a feature of California water policy; it was formalized in 1991 with legislative creation of a Water Bank, managed by the state Department of Water Resources. It has had a varied history. Created in 1991, after four previous drought years, it bought about 820,000 acre-feet of water, from 351 sellers, at $125/acre-foot. Nearly half of this was then sold to organizations with critical needs, at $175/acre-foot plus conveyance costs. All of this led to controversy, since some of the original water purchases came from people or organizations which relied increasingly heavily on groundwater, straining groundwater supplies in some areas. Critics said that as much of 162,000 acres of land went fallow, and that fish habitat was harmed in some places.
The biggest single buyers, though, were urban: the Metropolitan Water District of Southern California (215,000 af), the Kern County Water Agency (53,797) and the city of San Francisco (50,000). The first year of water bank activity:

Region			Category		Acre-feet	% of total
Delta			Fallowing		333,723	40.7
			Groundwater		2,529		.3
			Stored water		2,576		.3
Sacramento River	Fallowing		36,652		4.5
			Groundwater		46,787		5.7
Yolo			Fallowing		34,463		4.2
			Groundwater		27,308		3.3
Yuba/Feather		Fallowing		15,226		1.9
			Groundwater		182,341	22.2
			Stored water		139,200	17.0

Statewide		Fallowing		420,064	51.2
			Groundwater		258,965	31.5
			Stored water		141,776	17.3
						820,805