Imperial–San Diego Water Transfer (QSA) — Farm Water Conservation Funding Urban Supply and Salton Sea Mitigation (California, USA)

The 2003 Quantification Settlement Agreement (QSA) set up the largest agricultural-to-urban water transfer in the United States: up to 200,000 acre-feet a year from the Imperial Irrigation District (IID) to the San Diego County Water Authority for up to 75 years, alongside a 105,000 acre-feet-a-year IID transfer to Metropolitan and a transfer of up to 103,000 acre-feet a year to the Coachella Valley. IID holds an annual Colorado River allotment of 3.1 million acre-feet within California's former 4.4 million acre-feet entitlement. Reported deliveries to San Diego reached about 180,000 acre-feet in 2013.
The transfer reduces inflows to the Salton Sea. IID and the Water Authority initially sent mitigation water to the sea (this arrangement expired in 2018), and a joint powers authority including the state funds environmental mitigation. A 2015 task force set goals of 9,000-12,000 acres of habitat and dust suppression in the short term, and a 2017 State Water Board plan targeted 29,800 acres of ponds, wetlands and dust-suppression projects over ten years.
Caution: Imperial County and other plaintiffs challenged the deal under state environmental law; a Sacramento judge upheld it in 2013. Critics argue that Salton Sea decline imposes uncompensated environmental and public-health costs. Independent outcome data on net water, ecological and health effects were not found, so evidence is scored conservatively.

Read the full analysis: https://watereducation.org/aquapedia/quantification-settlement-agreement