UPDATE: The Marin Municipal Water District is taking immediate action by investing $387,685 to address urgent flood concerns in Nicasio. This decision follows significant resident protests against a now-canceled reservoir expansion project, which many feared would worsen flooding in the area.
Residents have reported increased flooding along Nicasio Creek and Halleck Creek, resulting in damage to roads, yards, and the local school. The district’s board convened on November 18, 2025, to approve a contract with Environmental Science Associates to investigate the underlying causes of these flooding issues.
Ben Horenstein, the district’s general manager, emphasized the district’s responsibility, stating,
“What we found is, without question, there’s district responsibility.”
The study aims to identify factors contributing to reduced creek flow and to evaluate long-term management strategies that could alleviate flooding impacts.
Board chair Matt Samson acknowledged the study’s high cost but deemed it necessary, saying,
“I appreciate the fact that we’re moving forward with it and better understanding…the impacts of what’s going on out there.”
Community members have expressed relief over the district’s response and are eager for ongoing engagement regarding flood management.
The previous proposal to expand the Nicasio Reservoir was initially seen as a cost-effective solution to enhance the county’s water supply. However, escalating project estimates, which soared from $10 million to as much as $54 million, led to its termination in August. Local residents celebrated this decision but urged the district to prioritize flood mitigation.
The current study is focused solely on understanding creek conditions without pursuing spillway modifications. Adriane Mertens, a district spokesperson, noted the importance of gathering objective data from stakeholders to address the flooding issue comprehensively:
“The study is not tied to pursuing spillway modifications.”
Community leader Martha Davis from the Nicasio Landowners Association stressed the need for continuous monitoring of the ecosystem. She emphasized,
“You’re going to need to understand how the system is responding to any of the changes that you’re making within it.”
Residents are also advocating for transparency regarding the district’s plans for a proposed 13-mile pipeline to import water from the Russian River to the Nicasio Reservoir.
As part of their commitment to flood management, the district is seeking emergency permits to remove accumulated debris from Nicasio Creek, which would help facilitate better water flow to the reservoir. If approved, this work could commence within the next two to three weeks.
The urgency of this situation highlights the community’s need for effective flood management solutions. Residents are hopeful that the district’s actions will lead to a safer and more sustainable environment as they navigate these pressing challenges together. As developments unfold, the community continues to seek clarity and collaboration with the district to ensure their concerns are addressed.
