About 15 miles north of Fresno sits Millerton Lake, a reservoir created in the 1930s when the U.S. Bureau of Reclamation built Friant Dam on the San Joaquin River. The dam provides irrigation water for fields and groves in much of the San Joaquin Valley, but it wiped out the Chinook salmon migration that had existed on the river for tens of thousands of years.
It also threatened the rights of landowners to divert naturally flowing San Joaquin River water for their fields. Instead of losing their rights, though, farmers who had land near the river agreed to trade their water to the federal dam project in exchange for “substitute water,” delivered to them from the Sacramento River.
This is one of several big water agreements, known as settlement or exchange contracts, that swapped water rights in order to permit construction of large projects in the 20th century, including the federal government’s massive Central Valley Project of dams, canals and aqueducts. In addition to the San Joaquin agreement, there are similar contracts for projects on the Sacramento and Feather rivers.
