The San Joaquin River Exchange Contractors hold some of the oldest water rights in the state, dating back to the late 1800s. The rights were established by Henry Miller of the legendary Miller and Lux cattle empire. In 1871, Henry Miller constructed canals to divert water from the San Joaquin and North Fork of the Kings Rivers for irrigation of his vast acreage. Today, several of the original Miller and Lux canals are operated by the Exchange Contractors.
Although Henry Miller’s canals served the irrigation needs of his estate in the western portion of Fresno, Madera, Merced, and Stanislaus counties, in order for more growth on the east side of the San Joaquin Valley to occur, more water was needed. In 1933, the United States Department of Interior undertook the Central Valley Project, a vast undertaking to build dams throughout the great Central Valley including the Sacramento, American and San Joaquin Rivers. When construction of the Friant Dam (north of Fresno) was under consideration, feasibility studies showed that irrigation development of the Friant Project between Chowchilla and Bakersfield depended upon water being diverted from the San Joaquin River at Friant Dam and brought to the east side of the valley, via the Friant-Kern Canal.
To accomplish this, the government asked the heirs of Miller and Lux to agree to “exchange” where they receive their pre-1914 appropriative and riparian water from the San Joaquin and Kings Rivers for guaranteed deliveries of “substitute” water from the Sacramento River by means of the Delta-Mendota Canal and other facilities of the United States. This agreement, known as the “Exchange Contract,” along with the accompanying “Purchase Contract,” were reached in 1939 and that led to the name “San Joaquin River Exchange Contractors.” In normal years, the Exchange Contractors are guaranteed 100% of their contractual water allotment (840,000 acre feet) and in critical years the amount is 75% (650,000 af).
The Exchange Contractors, however, did not abandon their San Joaquin River water rights. Instead, they agreed not to exercise those San Joaquin and Kings Rivers’ water rights if guaranteed water deliveries continued through the Delta-Mendota Canal or other facilities of the United States. In the event that the Bureau is unable to make its contracted deliveries of substitute water to the Exchange Contractors, the Exchange Contractors have reserved the right to receive their water from the San Joaquin River to satisfy their historic water rights.