Fourth District Finds CEQA Water Supply Analysis Fell Short for Lithium Project Near the Salton Sea
In Comite Civico del Valle v. County of Imperial, No. D085747, __ Cal.App.5th __, 2026 WL 2593390 (Aug. 11, 2026), the Fourth District Court of Appeal reversed in part, under CEQA, Imperial County’s approval of a geothermal power plant and lithium extraction facility near the Salton Sea. The court found the project’s environmental impact report (EIR) deficient in three key respects: The administrative record lacked substantial evidence that the Imperial Irrigation District (IID) could supply water for the project’s claimed 50-year lifespan; the EIR failed to adequately analyze the feasibility and environmental impacts of its water supply mitigation measures; and the EIR failed to discuss the project’s likely impact on air quality resulting from reduced drainage flows to the Salton Sea. The decision reinforces the principles set forth in Vineyard Area Citizens for Responsible Growth, Inc. v. City of Rancho Cordova, 40 Cal.4th 412 (2007), and offers important guidance for lead agencies and project proponents navigating long-term water supply analysis under CEQA.
Controlled Thermal Resources (CTR) applied to Imperial County for approval to build a geothermal power plant and companion lithium extraction facility. The project would use wells to bring up hot geothermal brine from beneath the Salton Sea, generate up to 49.9 megawatts of green energy, extract lithium hydroxide and other minerals, and reinject the spent brine into the geothermal reservoir. It required approximately 6,500 acre-feet per year (AFY) of raw water from IID—the sole provider of fresh water in the County—to operate. IID submitted a detailed comment letter on the draft EIR challenging the water supply claims, including assertions about the availability of water under IID’s Interim Water Supply Policy (IWSP) and the feasibility of a 50-year water supply. The County issued a final EIR and revised water supply assessment (WSA) in December 2023, and the Board of Supervisors approved the project in January 2024. Comite Civico del Valle and Earthworks filed a petition for writ of mandate; the superior court denied the petition, and appellants appealed.
The central issue on appeal was whether substantial evidence supported the County’s conclusion that IID could supply water for the project’s 50-year lifespan. The court began by noting a troubling inconsistency: Although the project proponents claimed on appeal that the project was designed for a 50-year term, the final EIR, final WSA, and Findings of Fact overwhelmingly referenced a 30-year lifespan and a corresponding water demand of 195,000 acre-feet. The court accepted for purposes of its review that the intended lifespan was 50 years—and then found the record could not support water availability for that duration.
Applying Vineyard’s four-part framework—which requires, among other things, that identified future water sources bear a likelihood of actually proving available and that the EIR discuss replacement sources and their environmental consequences where future supply is uncertain—the court found the final WSA at most supported confidence in a 30-year supply, assuming IID received its full Colorado River entitlement, a prospect the WSA itself acknowledged was uncertain. For the remaining 20-plus years, the EIR identified no other viable water sources, proposed no feasible independent conservation or augmentation projects, and did not discuss the environmental consequences of potential shortfalls. The court concluded this left “too great a degree of uncertainty regarding the long-term availability of water for this project” and constituted a prejudicial abuse of discretion.
The court also found the EIR’s water supply mitigation measure—designated UTIL-1—independently deficient. In its original form, UTIL-1 simply stated the applicant would “work with IID” to manage any reduction in water availability. IID objected that this was insufficient and that specific curtailment measures were required. The County revised UTIL-1 on the eve of the Board of Supervisors’ hearing, adding three possible operational changes: producing groundwater at the property, exploring temporary use of recycled drain water, and reducing production rates. The court rejected each as inadequately analyzed. The EIR elsewhere acknowledged that Imperial Valley groundwater is “generally of poor quality and unsuitable for domestic or irrigation purposes” and that the project was designed without any groundwater use. Use of recycled drain water would require a separate agreement with IID and additional CEQA review, with no evidence of feasibility. And reduced production conflicted with the EIR’s own alternatives analysis, which found scaling down infeasible because “engineers have not been able to identify a feasible way to scale the Project down.” The court further held that CEQA required the EIR to analyze the environmental impacts of the mitigation measures themselves—yet the EIR contained no such discussion.
The court likewise agreed with appellants that the EIR improperly failed to analyze the project’s impact on air quality resulting from reduced drainage to the Salton Sea. The parties acknowledged that the shrinking Salton Sea—and the resulting exposure of playa contaminated by decades of agricultural runoff—is the main contributor to poor air quality in the region. Because nearly all of IID’s Colorado River water is allocated to agriculture, any conservation of agricultural water for reallocation to the project would necessarily reduce drainage inflows to the sea. IID’s own comment letter expressly stated the project “will result in a net annual reduction of drainage flow to the Salton Sea” and connected this to air quality impacts. The court rejected the County’s argument that these impacts were speculative, finding the County’s assertion that it would “work with IID” to ensure compliance was an “unsupported conclusory statement that did not satisfy CEQA’s requirement of “good faith, reasoned analysis.” The court also rejected the County’s reliance on a 2009 negative declaration for the IWSP, finding that it addressed only water supply impacts and expressly stated that full CEQA analysis would be required for each project proposed under the policy.
The opinion carries several significant implications for lead agencies, project proponents, and CEQA practitioners. Most directly, it reinforces that a CEQA water supply analysis must match the project’s actual lifespan. Where a project is expected to operate for 50 years, compliance with the WSA’s 30-year projection does not end the CEQA inquiry; the EIR must also address reasonably foreseeable water-supply uncertainty over the project’s entire life. Agencies should ensure internal consistency across all CEQA documents regarding project duration and secure credible evidence of water availability for the full term—or, at minimum, follow Vineyard’s framework by acknowledging uncertainty, identifying alternative sources, and analyzing their environmental impacts.
The court’s treatment of UTIL-1 is also a reminder that simply listing potential operational changes in the event of a water shortage does not constitute adequate mitigation. Each proposed measure must be supported by evidence of feasibility, and its potential environmental impacts must be discussed—even if in less detail than the project’s primary impacts. Agencies cannot defer these discussions entirely, particularly where the EIR’s own analysis elsewhere casts doubt on the viability of the proposed measures.
Practitioners should also take note of the weight the court gave to IID’s comment letters. The court relied on IID’s technical objections to find both that the water supply evidence was insufficient and that the air quality impacts were not speculative. Lead agencies should take particular care in responding to comments from the entity that will actually supply the resource at issue—conclusory responses are unlikely to survive judicial review. And the air quality holding extends Vineyard’s logic into the nexus between water supply and other environmental resources, requiring agencies to trace the downstream consequences of water diversion decisions rather than dismissing them as speculative.
Finally, although the portion of the opinion addressing cumulative impacts was not certified for publication, it is worth noting that the court upheld the County’s use of the notice of preparation (NOP) publication date as the baseline cutoff for identifying cumulative projects. The court declined to adopt appellants’ argument that the EIR must be updated to address any project that becomes “reasonably foreseeable” at any point before certification, reasoning that such a rule could result in “endless review and revision.” For project proponents, this provides some comfort that there is a defensible endpoint for the cumulative impacts inquiry—but the published portions of the opinion make clear that getting the water supply analysis right from the outset remains essential.
