Below we provide updates on the latest developments in the ongoing Lopez Dam litigation and answers to some common questions following recent statements to the media from San Luis Obispo County regarding what this case truly means for our region’s water security and wildlife protections.
What is this case all about?
For decades, San Luis Obispo County has operated Lopez Dam and Reservoir without the necessary water rights permit. The County’s current permit effectively only allows the County to store water in the reservoir, but not to convey water from the reservoir to local water users. To comply with both state and federal law, the County must obtain a water rights permit that will allow it to legally deliver water to local users. To get such a permit, the County must also comply with the federal Endangered Species Act and various state law requirements and develop a complete and adequate plan for operating the reservoir in a balanced fashion that protects fish and wildlife while also meeting water supply needs.
Despite nearly 30 years of warnings, the County has failed to develop the plans needed to secure its water rights permit and related federal Endangered Species Act permit and has continued to fail to take the necessary actions to protect fish and wildlife from harms associated with reservoir operations.
In response, ForestWatch and partners took legal action to compel the county to finalize that permit and ensure long-overdue protections for steelhead and other endangered and threatened species. In November, 2024, in response to overwhelming factual evidence, a federal judge issued a preliminary injunction requiring the County to implement interim water releases and habitat improvements to protect the environment while a final decision is reached. The injunction also set a date-certain deadline for the County to submit a detailed habitat conservation plan to the federal wildlife agencies.
Despite the ruling’s temporary nature, the County has chosen to appeal rather than collaborate on a long-term solution. ForestWatch and our partners remain committed to working toward a balanced outcome that protects both the region’s water security and the survival of imperiled wildlife.
What does the preliminary injunction do?
The preliminary injunction is a court order requiring San Luis Obispo County to implement interim measures to protect threatened steelhead trout while the lawsuit is ongoing. This includes a requirement to release modest, specific amounts of water from Lopez Dam to ensure steelhead migration in Arroyo Grande Creek. The order also requires the County to submit a habitat conservation plan to the federal wildlife agencies by October 1, 2025. The plan is required by the Endangered Species Act and is also a necessary first step to securing a water rights permit that will allow the County to legally send water from the reservoir to local users.
This ruling does not permanently determine how the dam must be operated—it simply ensures improvements to habitat conditions for endangered species in the short term while long-term solutions are developed.
Why is the preliminary injunction notable?
Winning a preliminary injunction is significant because courts require strong, compelling legal and factual evidence before granting one. To succeed, we had to demonstrate that irreparable harm to steelhead would occur without immediate intervention and that our legal claims were likely to succeed at trial. This ruling affirms that the County’s operations likely violate the Endangered Species Act by harming steelhead, and it underscores the urgency of protecting steelhead while a final resolution is reached.
What science and data did the court rely on to set temporary water releases?
The ruling set temporary water release requirements based on the County’s own consultants’ analysis, which determined the flows necessary to support steelhead migration and habitat. The court relied on scientific data and expert recommendations to ensure compliance with the Endangered Species Act while balancing water resource considerations. Notably, over 20 years ago the County committed to federal and state resource agencies that it would implement a similar temporary water release program, but then declined to do so.
Does the preliminary injunction threaten the local water supply?
No. The preliminary injunction is temporary and ensures threatened steelhead receive adequate flows while a final solution is developed. Lopez Reservoir is near full capacity, making the county’s claim that the ruling threatens water supply during the short time it is in effect is false. The court-ordered flows are proportionally small compared to other existing water demands, including municipal, agricultural, and discretionary releases. The County’s assertion that these requirements are permanent suggests it in fact has no real intention of finalizing a wildlife protection plan with wildlife agencies, further affirming our original motivation to legally intervene.
Does the ruling impact the fire department’s ability to respond to wildfire?
No, these wild assertions play off of the current political climate to spread fear and misinformation. The ruling does not impact the fire department’s ability to respond to wildfires. Lopez Reservoir is near full capacity, and fire agencies have multiple water sources available for firefighting. The county’s claim that the court-ordered releases jeopardize fire suppression is misleading and ill-informed. Consider that the largest helicopter fire buckets hold about 2,600 gallons. At 5% of its capacity, Lopez Lake would provide enough water for over 300,000 drops of water from helicopters. Again, the required flow adjustments are proportionally small, temporary, and do not diminish emergency response capabilities.
Indeed, authorities successfully fought the recent large Gifford fire in land near Lopez Reservoir without significant impact to the amount of water stored in the reservoir. As is publicly reported on the County’s website, the reservoir remains substantially full– and is presently at about the same capacity as it was before the fire.
Who is really using the most water, and why is wildlife being blamed?
Before pointing fingers at wildlife protections, the County should take a closer look at where the bulk of the water from Lopez Reservoir is actually going. According to publicly available data housed by the State Water Resources Control Board, in 2021 and 2022, a single private agricultural entity diverted more water from Arroyo Grande Creek than the combined municipal demand of all five cities that rely on Lopez Reservoir! Yet, the county claims that modest, science-based flow releases for steelhead are the real problem. The real question isn’t whether we can balance wildlife needs—it’s why a small number of private interests are receiving the lion’s share of water while the county fights protections that benefit the entire ecosystem and community. Instead of attacking steelhead protections, we should be asking whether our water is being equitably managed for everyone.
What solutions is the county ignoring while pointing fingers?
Before our citizen suit, the County was following its Interim Downstream Release Plan which included a Low Reservoir Response Plan that only kicks in after Lopez Reservoir is already 60% depleted, instead of taking proactive steps to manage water sustainably before shortages occur. The County’s approach did not discuss how conservation efforts could reduce demand or how investments in groundwater recharge and other water supply augmentation projects could help secure long-term resilience. Instead of working toward forward-thinking solutions, the county is using steelhead protection as a scapegoat while ignoring the bigger issue of outdated, reactionary water management policies that put the region at greater risk. If the County truly wanted to address water security, it would be focusing on smart conservation, efficiency, and diversified water solutions, all of which will be required for the County to secure the legal right to continue using Lopez reservoir—instead of fighting environmental protections.
Who pays for the County’s legal delay tactics?
Residents of the Five Cities are paying for the County’s legal fight over Lopez Dam, even though the San Luis Obispo County Board of Supervisors decides whether to settle or continue litigating. So far, more than $2 million in taxpayer money has gone to the County’s attorneys—over twice as much as the County has invested over the past 26 years in developing the environmental study and habitat restoration projects that are necessary to bring dam operations into compliance with the law.
Instead of funding solutions, the County’s lawyers recently argued in court that the dam has never impacted steelhead trout. This claim directly contradicts decades of findings from state and federal wildlife experts, as well as the County’s own consultants.
Did steelhead once thrive in Arroyo Grande Creek?
Yes. Arroyo Grande Creek historically supported a thriving steelhead trout population that was central to the creek’s ecology and local recreation.
- Early Abundance
Historically, Arroyo Grande Creek had a robust, self-sustaining steelhead population and the creek was popular with anglers fishing for steelhead. As many as 25,000 adult steelhead more at one time estimated to return to the creek. A page in Robert A. Brown’s The Story of the Arroyo Grande Creek describes how “steelhead would fill the creek as they propelled their great silvery bodies inland.” Trophy-sized, caught steelhead trout were regularly featured in local newspapers. - Decline After Lopez Dam
The construction of Lopez Dam in the mid-1960s blocked access to the majority of the creek’s historic high-quality steelhead spawning and rearing habitat. Post-dam surveys have documented that the present steelhead population is a small remnant of what was once found in the creek, with at most several hundred or even less adult steelhead now returning to the creek to attempt to spawn. - Recognition of Threatened Status
By 1997, steelhead populations across California’s Central Coast, including Arroyo Grande Creek—were listed as Threatened under the Endangered Species Act.
The County says it’s already complying and working with federal agencies to resolve the issue. Is this accurate?
No. The County has not secured the required state water right license to operate Lopez Dam, despite nearly 30 years of discussions. While County officials often claim they are “working with federal agencies,” in reality their efforts have amounted to little more than a “plan to make a plan.” For example, rather than committing to specific flow releases in line with agency recommendations, habitat improvements, or operational changes that would benefit steelhead, the County has largely only proposed additional studies and frameworks for future negotiations without adopting any enforceable measures that would actually protect steelhead or satisfy state water right licensing requirements. During this time, the County has continued to divert water from the creek without addressing the impacts on steelhead trout and other wildlife. Furthermore, as noted above, the County continues to try to contradict in court the overwhelming evidence that its Lopez Dam operations are jeopardizing steelhead survival, rather than devote its resources to finding a balanced solution for protecting steelhead while providing necessary water supply to local communities.
Until the County commits to enforceable measures that both secure a valid water right and protect threatened species, its claims of compliance remain misleading.
What would a real solution look like?
A real solution would bring Lopez Dam into compliance with the law by securing a valid state water right license that includes enforceable protections for steelhead trout and other wildlife. This means committing to practical, science-based measures such as releasing sufficient water from Lopez Dam to support fish migration and spawning, restoring stream habitat downstream of the dam, and modernizing operations to balance human water needs with the health of our rivers. These actions are both feasible and necessary. By adopting them, the County could finally resolve a 30-year problem, protect threatened species, and provide lasting water security for the Five Cities.
What happens if the County keeps delaying in court?
If the County continues down the path of endless legal delays, Five Cities residents will keep paying millions of dollars in legal bills without getting any closer to a real solution. Every dollar spent on delay tactics in litigation is money that could otherwise fund completion of the environmental studies and improvement projects that the County must perform to secure its water right and projects to improve water efficiency and diversify water supply. Even if the lawsuit were to go away, the fundamental problem would remain: the County still lacks a valid water right license and still hasn’t addressed the dam’s impacts on steelhead. Until those issues are resolved, the problem of noncompliance doesn’t go away.
Who is responsible for making the final decision?
While residents of the Five Cities are paying all the legal bills through their water rates, the San Luis Obispo County Board of Supervisors has the ultimate authority over the ongoing litigation and any settlement decisions. This means the Supervisors could choose to end the wasteful legal delays at any time and direct resources toward compliance and environmental protection instead. Unfortunately, as long as the Board chooses to continue fighting in court while also failing to complete adequate environmental improvement plans needed to secure the necessary water right license for the dam, taxpayers in the Five Cities will keep bearing the financial burden.
What’s next?
ForestWatch and our partners remain committed to working with the County to develop a long-term solution that balances water security, agricultural needs, and the survival of threatened steelhead. Unfortunately, the County has yet to step forward with any constructive proposals or meaningful efforts to resolve the issue. Instead, its decision to appeal threatens to derail progress entirely—at great expense to taxpayers. We continue to hope that stronger leadership will emerge to change the current course, abandon political posturing, and focus on real solutions—ones that secure a sustainable water future for both people and wildlife