Appeals Court Issues Key Decision in San Luis Obispo County Lopez Lake ESA Case

San Luis Obispo County won an appeal in a long-running dispute with non-profit environmental groups over whether Lopez Lake operations violated the federal Endangered Species Act (ESA). 

The Ninth Circuit Court of Appeals issued its ruling on December 3, 2025, siding with the County.

The appellate panel overturned a prior injunction that required San Luis Obispo County to release more water from Lopez Lake to benefit threatened steelhead trout.

The judges found the lower court had not sufficiently analyzed how those increased releases might affect other protected species. 

The Ninth Circuit sent the case back to the district court for further review, directing the judge to reassess the balance of impacts on all listed species before determining whether an injunction is warranted.

Officials React to Ruling

County officials welcomed the ruling, saying it supports efforts to balance habitat protection with local water supply needs.

Supervisor Jimmy Paulding noted the ecological complexity of the watershed, while Chair Dawn Ortiz-Legg said the County hopes the decision will encourage collaboration moving forward.

Public Works Director John Diodati added that the ruling aligns with their long-term plan and federal review process.

SLO County’s Appeal

In its January 2025 appeal, the County argued that the injunction could significantly reduce Lopez Lake levels during dry years. This could potentially affect drinking water for about 50,000 residents, firefighting readiness, and downstream habitats, the County noted at the time. 

The County also stated that the extra releases are not supported by science and could harm other protected species, including the California red-legged frog and tidewater goby, that depend on that water. 

According to the appeal, several statewide organizations, including water agencies, agricultural groups, and the Pacific Legal Foundation, expressed support for the County’s position. 

A preliminary injunction issued on November 27, 2024, required the County to adopt a new reservoir-based release plan, maintain culverts, design a fish screen for Lopez Dam, and study potential options for steelhead passage. 

The court found that existing dam operations could harm threatened steelhead under the ESA.

Los Padres ForestWatch’s Argument

Los Padres ForestWatch argued that the County has operated Lopez Dam for years without a full water rights permit and has not completed the planning steps needed for ESA compliance. 

The organization also stated that the County overlooked repeated agency warnings and did not finalize long-term plans intended to protect fish and wildlife.

Lopez Lake predates the ESA. ForestWatch notes that the County’s existing permit covers storage but not full delivery rights, and that obtaining those rights requires compliance with state and federal environmental standards, including completion of a Habitat Conservation Plan.