By Brad Barham & Robert Marcos
It’s now painfully clear that the Colorado River is a limited resource which has been decreasing in flow for the past 25 years. Therefore new water conservation and transfer initiatives are more critical than ever to the continued economic and social vitality of the Southwest. An excellent example of this was provided in 2003 by the QSA between San Diego and the IID.
In 2003 the San Diego County Water Authority (SDCWA) and the Imperial Valley Irrigation District (IID) forged a mutually beneficial water partnership that demonstrated that urban sustainability and agricultural prosperity could thrive together. In their “Quantification Settlement Agreement“, the SDCWA provided major infusions of capital to the IID in exchange for an annual allotment of 200,000 acre feet of Colorado River water, accounting for more than half of the region’s water supply. The SDCWA received an additional 77,700 acre-feet of water that was conserved by lining long stretches of the All-American and Coachella canals.1, 2
At the time of the historic agreement San Diego County’s population had just passed the 3 million mark and 95% of its water had been coming from a single source: the Metropolitan Water District’s Colorado River allotment. Worse – it would be 12 more years until San Diego’s very expensive desalination plant would come online, offering a new source of water that supplies only about 10% of the county’s water use.. This meant that prior to the QSA the county’s water supply was exceptionally vulnerable to shortage.
From the IID’s point of view, their massive 3.1 million acre-foot (AF) Colorado River allotment had a major vulnerability: unlined earthen canals had been losing up to 100,000 AF of water every year through seepage. In addition to this the IID wanted farmers to employ more advanced irrigation systems but their investment costs limited adoption. That changed after the influx of hundreds of millions of dollars from San Diego and the State, which provided the financial lifeline needed to pay for the upgrades.
1. San Diego paid for an array of on-farm conservation upgrades: Under the QSA only water that was saved due to the following efficiency upgrades could be transferred to San Diego. 3
- Drip Irrigation Systems
- Portable & Fixed Sprinkler Systems
- Tailwater Return (Recovery) Systems
- Cascade Systems
- Laser Land Leveling
2. System and Infrastructure Conservation: San Diego funds IID’s internal delivery system improvements to generate water efficiency. 4
- Regulating & Mid-Lateral Reservoirs
- Delivery System Automation
- Main Canal Seepage Interception projects
3. All-American and Coachella Canal Concrete Lining: Paid for via QSA Partnerships
Through the QSA, San Diego secured $257 million in State of California subsidies to pay for the massive physical construction of concrete-lined sections of these earthen canals. This prevents massive water loss from seepage and provides San Diego with an additional ~80,000 acre-feet of water annually. 5
4. Historical Land Fallowing — Paid for through 2017
During the initial years of the QSA (2003–2017), before farmers had time to build modern drip and tailwater systems, San Diego paid for temporary land fallowing to kickstart the water transfer volumes. They also provided $30 million to mitigate environmental and economic impacts on the Imperial Valley from idling those fields. 6
San Diego and the Imperial Irrigaton District weren’t the QSA’s only beneficiaries
• Coachella Valley Water District (CVWD)
Prior to the QSA the Coachella Valley Water District received as much as 330,000 acre feet of Colorado River water, but those deliveries had been unreliable, and as a result the Coachella Valley’s groundwater was in a state of severe overdraft. Thanks to the QSA, CVWD’s water rights were officially quantified, the district received an immediate, additional 35,000 acre-feet of Colorado River water, and its long-term imported supply was scheduled to steadily increase over time. 7
• Metropolitan Water District of Southern California (MWD)
The Metropolitan Water District of Southern California, the massive wholesale supplier for cities across Los Angeles, Orange, Riverside, San Bernardino, and Ventura counties—was a core player. While MWD took a reduction in some historic surplus supplies to help California stay within its strict 4.4 million acre-foot total river limit, the QSA secured and stabilized MWD’s baseline water rights. It granted MWD reliable access to dry-year water transfers from agricultural areas (like the Palo Verde Valley) and canal-lining projects. This reliably safeguards the water supply for more than 12 million urban Southern Californians outside of San Diego. 8
• The San Luis Rey Indian Settlement Parties (Native Tribes)
A crucial portion of the water saved from the All-American and Coachella canal lining projects was legally designated for five San Diego-area Native American tribes. These included the La Jolla Band of Luiseño Indians, Pala Band of Mission Indians, Pauma Band of Luiseño Indians, Rincon Band of Luiseño Indians, and the San Pasqual Band of Mission Indians. For decades, these tribes had been locked in a fierce federal water rights dispute with local cities. The QSA permanently resolved this by allocating 16,000 acre-feet of water per year from the canal lining projects to these tribes and their partner cities of Escondido and Vista. 9