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colorado river aerial view

Colorado River Provides Highly Reliable Supplies

The Water Authority’s supply portfolio includes high-priority, independent Colorado River supplies negotiated through the landmark 2003 Quantification Settlement Agreement, or QSA. These highly reliable supplies are the cornerstone of the San Diego region’s long-term water supply diversification strategy.  In addition, the Water Authority purchases Colorado River water from the Metropolitan Water District (MWD) of Southern California.

Before 2003, the Water Authority purchased all of its imported water supply from the MWD, which owns and operates the 240-mile long Colorado River Aqueduct. Dependence on a single supplier increased the risk of water shortages.

A Water Gateway

By developing large, independent supplies from the Colorado River, the Water Authority enhanced water reliability and minimized the risk of serious shortages for San Diego. The QSA supplies include a conservation-and-transfer agreement with the Imperial Irrigation District and water conserved by lining portions of the All-American and Coachella canals. The Water Authority receives approximately 280,000 acre-feet annually from these efforts, comprising around half  of the San Diego region’s total water supply.

The Water Authority continues to work with water agencies, states and the Bureau of Reclamation on Colorado River issues and water management strategies that would provide the Water Authority additional operational flexibility and benefit the Southwest and Basin states.

all american canal at sunset

Colorado River Quantification Settlement Agreement

In October 2003, the San Diego County Water Authority, Coachella Valley Water District, Imperial Irrigation District, Metropolitan Water District of Southern California, State of California and U.S. Department of the Interior completed a historic set of agreements to conserve and transfer Colorado River water.

download this documentQualification Settlement Agreement (QSA) Fact Sheet

The San Diego County Water Authority sits on the QSA Joint Powers Authority Commission, the governing board formed under the 2003 legislation to administer funding of environmental mitigation requirements related to the QSA water transfers. For more information about the QSA JPA, go to QSAJPA.org.

Key Benefits

Known as the Colorado River Quantification Settlement Agreement, or QSA, the agreements settled decades of dispute over Colorado River water. The QSA has held up to scrutiny under several unsuccessful legal challenges in state and federal courts.


Reducing California’s Over-Dependence on Colorado River

The QSA enabled California to reduce its historic overdependence on the Colorado River through voluntary agriculture-to-urban water transfers and other water supply programs. The state can now live within its 4.4 million acre-foot entitlement.


Restoring the Salton Sea

Legislation associated with the QSA makes restoration of the Salton Sea a state responsibility. In March 2017 the State of California produced its Salton Sea Management Program, which provides a path toward a smaller, but more sustainable, Salton Sea. In November 2017, the State Water Board adopted a stipulated order, acknowledging additional agreements and commitments reached among key stakeholders related to the management program. There is over $300 million available in the State’s budget and efforts are underway to secure additional funding for the program.


Providing Water

The QSA provides more than 30 million acre-feet through conservation over the life of the transfer programs.


Fostering Mutual Benefits

QSA funds support conservation, economic diversification, agricultural growth, environmental mitigation, and protection of long-standing water rights.

Water Transfer
farming irrigation spraying on the fields

Water Transfer Agreement

As part of the QSA, the Water Authority-Imperial Irrigation District (IID) water transfer provides  200,000 acre-feet of water a year for San Diego County through water conservation measures in Imperial Valley. It is the largest agricultural to urban water transfer in the nation.

Supported by annual funding from the Water Authority, IID conserves through a combination of system conservation and on-farm conservation methods. In 2010, the Water Authority also provided IID with $50 million to assist in these efforts. IID is using the money for the exclusive purpose of constructing system-conservation capital improvement projects. Between 2003 and 2017, the Water Authority also provided $30 million to IID to help diversify the Imperial Valley economy and mitigate socioeconomic impacts of the water transfer.

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.

download this documentWater Transfer Agreement Fact Sheet

Agreement Highlights

The water transfer has become a critical part of the Water Authority’s diversification strategy implemented to better serve its member agencies. Through the water transfer, San Diego County has gained a highly reliable and safe water supply to serve generations to come. The transfer protects against shortages and stabilizes the price of a significant portion of the Water Authority’s overall supplies.

The transfer agreement in combination with the canal lining projects allows the Colorado River to provide SDCWA with a growing supply of water.

Agency Roles

IID is responsible for determining how to produce the conserved water, except that fallowing was only permitted during the initial 15 years. MWD takes delivery of transfer water at Lake Havasu via the Colorado River Aqueduct and delivers to the Water Authority a like quantity and quality of water in exchange.

Transfer Water Pricing

Through 2034, the price of the transfer water will be based on the annual increase in the Gross Domestic Product Implicit Price Deflator published by the Bureau of Economic Analysis of the U.S. Department of Commerce. 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 2035.

JPA & Environmental Mitigation Funds

The QSA Joint Powers Authority (JPA) 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 each from the Water Authority, CVWD, and IID.  The Water Authority is responsible for administering the JPA.

Transfer Data

Recorded and projected data of the various San Diego County transfer points on the Colorado River.

Canal Lining

Canal Lining Projects

The All-American and Coachella canal lining projects are critical components of the QSA, providing approximately 80,000 acre-feet a year of conserved canal water to San Diego County for 110 years. Over the term of the agreement, 8.5 million acre-feet will flow to San Diego County. Additionally, 16,000 acre-feet of water per year from the projects is sent to several bands of Mission Indians in northern San Diego County, settling a water rights dispute and decades of litigation.

The 82-mile All-American Canal located in the southeastern corner of California conveys water from the Colorado River to California’s Imperial Valley. The 123-mile Coachella Canal is a branch of the All-American Canal that delivers water to California’s Coachella Valley.

download this documentCanal Lining Projects Fact Sheet

Project Highlights


Concrete Lining

After the QSA was signed in 2003, approximately 23 miles of concrete-lined parallel canal was constructed next to the original All-American Canal, and 35 miles of concrete-lined parallel canal was constructed next to the original Coachella Canal. Water flows were then diverted into the concrete-lined sections, significantly reducing seepage through the earthen canals and allowing conserved water to be put to use.


Annual Water Flow

The Coachella Canal Lining Project was completed in 2007, when 26,000 acre-feet per year of conserved water began flowing to project beneficiaries. The All-American Canal Lining Project was completed in 2010, when its full yield of 67,700 acre-feet per year was made available.


Environmental Mitigation

The canal lining projects required extensive environmental mitigation, some of which is ongoing. As part of the fishery mitigation requirement, fish were relocated from the canal systems into nearby lakes prior to construction, and a 50-acre Sports Fishery Pond was constructed on the Wister Waterfowl Management Area that is owned by the California Department of Fish and Wildlife.

Additionally, 17 acres of marsh were constructed in the Dos Palmas Area of Critical Environmental Concern, providing new habitat for wildlife. Ongoing mitigation efforts include upgrading the water supply system, maintaining and monitoring existing habitats in Dos Palmas Oasis and restoring 352 acres of desert riparian habitat.

Salton Sea
salton sea shore

Salton Sea

The Salton Sea is the largest lake in California, covering about 375 square miles of Imperial and Riverside counties. It is in the Salton Basin, which from the earliest documented history has periodically filled with water, most notably ancient Lake Cahuilla.

In its current form, the Salton Sea was created when a dike gave way and the Colorado River flooded the basin in 1905. Since then, the sea has been fed mainly by agricultural runoff in the New and Alamo rivers (which start in Mexico and flow through the Imperial Valley) and the Whitewater River in the Coachella Valley.

The Salton Sea provides habitat for a wide range of bird species, including migratory birds on the Pacific Flyway. Efforts by the Water Authority and partnering agencies (Coachella Valley Water District and Imperial Irrigation District), to provide environmental funding under the QSA Joint Powers Authority (JPA), are a critical component of the sea’s future.

download this documentSalton Sea Fact Sheet

Joint Powers & Mitigation

Through that ongoing effort, the JPA has mitigated the impacts of the water transfers from the start and set the stage for the state to carry out its responsibility for a restoration program at the sea.

Funding Agreements

As part of the JPA, the three water agencies committed to pay up to $133 million in 2003 dollars, or $288 million in nominal dollars. Under state law, any mitigation expenses above $133 million are the unconditional responsibility of the State of California. Additionally, the Water Authority, IID, and CVWD agreed to pay $67 million in nominal dollars as seed money to jumpstart the state restoration program. The Water Authority has fully paid its share of the restoration funding.

The Water Authority has met all of its financial commitments since 2003 and is in compliance with all state and federal environmental obligations.

Water Transfer Mitigation

Most of that funding has gone toward providing bucket-for-bucket mitigation water to the Salton Sea from 2003 through 2017 to eliminate any impact of the water transfers on the sea’s shoreline.

Air Quality Projects

JPA funding has also paid for the placement of six stations around the sea to monitor air quality, construction of a 950-acre managed marsh as new wildlife habitat, and a series of air quality pilot projects to test the most effective ways to address potential QSA impacts around the sea since mitigation water deliveries ended in 2017. In 2018, the emphasis shifted from pilot projects to larger implementation of on-the-ground air quality projects.


Regional Conveyance System Study

As part of its regional water supply planning, the Water Authority has been studying delivery alternatives for its independent Colorado River supplies that it receives through the Quantification Settlement Agreement. A two phase study is underway that is assessing the feasibility of a pipeline system to directly and cost effectively convey these supplies from Imperial Valley to the San Diego Region.

In August 2020, the Water Authority released the final Phase A report that shows that building a new conveyance system is technically feasible and cost-competitive with other long-term options for meeting the region’s water needs. In November 2020, the Water Authority Board approved proceeding with study Phase B, which is underway and expected to be complete in summer 2022. Phase B includes refining Phase A technical analysis and cost estimates, performing an economic analysis, and engaging with stakeholders and potential partners.

download this documentRegional Conveyance System Study Fact Sheet – San Diego Region download this documentRegional Conveyance System Study Fact Sheet – Imperial Valley

Key Study Points

Current Conveyance System

The Water Authority currently pays the Metropolitan Water District of Southern California to transport Quantification Settlement Agreement water from the Imperial Valley through the Colorado River Aqueduct to the San Diego region. This delivery agreement (Exchange Agreement) expires in 2047 for the water transfer but is in place for the entire 110-year term of the canal lining supplies. The current Water Transfer Agreement between the Imperial Irrigation District and the Water Authority continues to 2047 but both agencies can agree to extend the transfer another 30 years to 2077. The Water Authority is studying alternatives for transportation of this water beyond 2047.

Study Phase A – Engineering & Cost Analysis

The Phase A report is the result of technical and cost analysis by Black & Veatch Corp. and the preliminary economic analysis by Water Authority staff. The engineering firm conducted similar studies as part of the Water Authority’s Regional Water Facilities Optimization and Master Plan Update, dating back to 1996, assessing “single use” water-delivery projects in those studies. The current analysis looks at a conveyance project with multiple partnership possibilities and potential regional benefits that align with the Governor’s Water Resilience Portfolio.

Three potential routes for the pipeline were considered as part of the Phase A which focused on engineering analysis to update costs and identify any technical or financial fatal flaws. No fatal flaws were identified and two of the rates were deemed cost-competitive with other options.

Study Phase B – Funding & Partnership Assessment

Phase B of this study, currently underway, is refining the analysis for the two remaining routes with a focus on assessing potential partnerships and funding opportunities, as well as conducting a detailed economic analysis and robust stakeholder outreach.