Colorado River Supplies Management

Draft Regional Conveyance System Study - Phase A

A draft report released in June 2020 by the Water Authority shows that building a new conveyance system to transport regional water supplies from the Colorado River Quantification Settlement Agreement is cost-competitive with other long-term strategies for meeting the region’s water needs.

Three potential pipeline routes were studied in the Phase A draft report, which says two alternatives (3A and 5A) are cost-competitive with other options, such as relying more on the Metropolitan Water District of Southern California or developing additional local supplies.

The draft Phase A report is under review by water officials across the region, and the Water Authority’s Board of Directors is expected to decide whether to move to Phase B at its meeting on August 27, 2020.

The Water Authority’s water supply portfolio includes a suite of relatively new supplies from the Colorado River. These supplies include a water transfer conservation and transfer agreement with the Imperial Irrigation District and water conserved by two projects, the All American Canal Lining Project, and the Coachella Canal Lining Project

The Water Authority will receive approximately 180,000 acre-feet of its supply from these sources in calendar year 2015. By 2020, these supplies are expected to produce approximately 280,000 acre-feet, and comprise more than 30 percent of the Water Authority’s total water supply. The chart shows the projected yield of these three projects.

The transfer and canal-lining projects were enabled by the 2003 Quantification Settlement Agreement, which allowed major water conservation and transfer programs to be implemented by California’s agricultural Colorado River contractors. The conserved water is made available for water users in Southern California’s urban coastal area, who pay for the conservation programs. 

The Water Authority continues to work with other Colorado River contractors and states to develop additional Colorado River water supplies and water management strategies. The Water Authority participated in a study by the U.S. Bureau of Reclamation of overall water demand and supply conditions in the entire seven-state Colorado River Basin, and is working together to address projected water supply and demand imbalances in the Colorado River Basin, with an eye toward augmenting limited Colorado River supplies.

Water Transfers 2003-2021

The Water Authority is also participating with U.S. and Mexican agencies in a review of potential water management and water supply programs that could benefit Colorado River water users of both countries. As part of this effort, the evaluation and preliminary design of an initial 25 million gallons per day ("MGD") (expandable to 50 MGD) seawater desalination plant that would be located at Rosarito Beach in Baja California, Mexico is being pursued. Currently, the Rosarito Beach Desalination Project is considered a conceptual-level project. If built, product water from the plant would be available to both U.S. and Mexican water users. For U.S. water users, the water could be delivered either directly to the San Diego region, using a cross-border pipeline, or possible by exchange, with Mexican users taking delivery of the product water and leaving an equivalent amount of Colorado River water available for U.S. users.

Before 2003, the Water Authority purchased all of its imported water supply from the Metropolitan Water District. The dependence upon a single supplier increased risk of water shortages. By creating large, independent supply sources from the Colorado River, the Water Authority is able to enhance its water supply reliability and minimize the risk of serious water shortages in the region. The Water Authority’s Colorado River supplies provide a strong foundation for a diverse and reliable water supply.