Water Authority–Imperial Irrigation District Water Transfer

Increasing access to highly reliable supplies of Colorado River water is critical to the Water Authority’s effort to diversify the region’s water supplies.  Water conservation and transfer agreements through the QSA, are key components of the Water Authority’s supply portfolio.


Water conservation and transfer agreements that were completed in October 2003 will provide an additional approximately 280,000 acre-feet of water annually to the San Diego region. The Water Authority-Imperial Irrigation District water transfer will provide up to 200,000 acre-feet of water a year through water conservation measures in Imperial Valley. The transfer is the cornerstone of the Colorado River Quantification Settlement Agreement, a broader plan that reduces California's use of Colorado River water to its basic annual apportionment of 4.4 million acre-feet.

Term: The initial term of the Water Authority-IID Water Transfer Agreement is 45 years. If both parties agree, the agreement can be renewed for an additional 30 years. The Water Authority can, however, elect to terminate the agreement after 35 years if the cost of transporting the water to San Diego is unacceptable. In the event of a non-renewal, each party has a right of first refusal on transfers for a period of 15 years following the initial term.

Conservation Method: IID is responsible for determining how to produce the conserved water, except that fallowing was only permitted during the initial 15 years.

Quantity: In a ramped-up schedule, the Water Authority will receive 200,000 acre-feet of water per year by the end of year 19 (2021). The delivery quantity increases according to a schedule until reaching 200,000 acre-feet.

Delivery: MWD takes delivery of transfer water via the Colorado River Aqueduct and delivers to the Water Authority a like quantity and quality of water in exchange.

Price: Payments from the Water Authority to IID started in 2003 at $258 per acre-foot and increase each year according to a set schedule until 2015. For 2016 through 2034, the price per acre-foot will be based on the annual increase in the Gross Domestic Product Implicit Price Deflator as published by the Bureau of Economic Analysis of the United States Department of Commerce applied to the prior year price per acre-foot. Beginning in 2035, either the Water Authority or IID can, if certain criteria are met, elect a market price through a formula described in the water transfer agreement. In addition, a shortage premium price can be imposed, under certain conditions, after year 2035.

Joint Powers Authority: A QSA Joint Powers Authority  was established in 2003 to collect, hold, invest, and disburse the funds necessary for environmental mitigation required for the Water Authority’s and Coachella Valley Water District’s (CVWD) water transfers with IID. The governing body of the JPA is a commission of four members, including one representative from the state’s Department of Fish and Wildlife, who chairs the commission, and one member from the Water Authority, CVWD, and IID.  The Water Authority is responsible for administering the JPA.

icon_pdf.pngQuantification Settlement Agreement for the Colorado River Fact Sheet




The transfers are key components of the Colorado River Quantification Settlement Agreement, which allows California to implement measures to reduce California's dependence on Colorado River water.

Southern California

The transfers replace water that was lost to the region as California complies with the mandate to live within its basic Colorado River annual apportionment of 4.4 million acre-feet. For many years, more than half the water the Metropolitan Water District (wholesale supplier to urban Southern California water agencies) received from the Colorado River was a surplus supply. With the execution of the QSA, Southern California can gradually wean itself of its over-dependence on the Colorado River.

San Diego County

San Diego County has gained a highly reliable water supply that helps to diversify and ensure the reliability of the region's supply for generations to come. The transfers protect against shortages and stabilize the price of a significant portion of the Water Authority's overall supplies.

Imperial Valley

The Imperial Valley protects its historic water rights. It is receiving money to pay the costs of the transfer program and environmental mitigation. Moreover, funding will help the Imperial Valley diversify its economy.

The Water Authority-IID Water Transfer provides benefits to San Diego and Imperial counties and the rest of California. The All-American and Coachella canal lining projects also represent a significant new long-term supply of water. These programs are key to the QSA, California's plan to live within its Colorado River water allocation – a plan in which all participating water agencies as well as all Colorado River users share an interest.