Stay up to date on Marin Water’s proposal to raise the Nicasio Reservoir.

The NLOA has created this page to help our community better understand and respond to the proposed changes to the Nicasio reservoir. Scroll down for more information.

ANNOUNCEMENTS:

  • 5/16: MMWD agrees to push back deadline for feedback from June 4th to August 4th!

  • 5/27: Because of our collective efforts, MMWD requests additional funding to study “upstream effects” off the proposed project (“staff have identified the need to conduct detailed hydrological analysis to the upstream reaches of the reservoir into Nicasio and Halleck Creeks.”)

  • Link to the Nicasio School page on this issue.

IN THE NEWS

IMPORTANT DATES

Thursday, June 26th at 5:00pm: an important meeting with the directors of Marin Water. To be held at the Nicasio School (ground zero for flooding). The format will include a presentation from the Marin Water board and then Q&A. The Directors are the ultimate decision makers on this project, so this is a great forum for them to hear directly from you and respond to specific questions.

Tuesday July 15: As part of the environmental review process, Marin Water is holding three public scoping meetings. These meetings are an opportunity for interested parties to learn more about the project and provide public comments. The information presented will be the same for all three meetings.

What is
Marin Water Proposing?

Description from Marin Water:

“Nicasio Reservoir was created by the construction of Seeger Dam, an earthen filled dam on Nicasio Creek in 1960. The reservoir's current storage capacity is 22,340 acre-feet. This project would install a 280-foot-long, 4.4-foot-high inflatable rubber gate spanning the width of the existing spillway crest of Seeger Dam to increase the capacity at Nicasio Reservoir by approximately 3,700 acre-feet. Modifying Nicasio Reservoir’s spillway is one of the near-term storage enlargement projects identified in the District's Water Supply Roadmap.”

> Link to the Notice of Preparation (NOP)

> Link to Marin Water Supply Roadmap

> Link to Marin Water Board meeting agenda page (see videos of past Board member discussion about the Nicasio Project and watch upcoming Board meetings on zoom)

> Link to MMWD project page

Why we are revising our previous position

As of June 11 2025, the NLOA is revising its official position on Marin Water’s Proposal to raise Nicasio Reservoir (see our revised position below). We are altering our stance for the following reasons:

  1. Inaccurate Marin Water Maps don't reveal the real extent of potential flooding caused by the project.
    Marin Water’s inundation maps fail to show the extent of the winter season flooding that occurs now in Nicasio.  These maps don’t reveal the far worse winter flooding that the proposed project will cause.

  2. Video and photographic evidence of recent winter floods underscores how flooding will expand and intensify if Nicasio Reservoir is raised.
    New information provided by community members documents serious current flooding issues related to Marin Water's failure to manage sediment build up near the mouths of Nicasio and Halleck Creeks.  The additional flooding caused by the proposed project will devastate the historic Nicasio school site plus severely impact multiple private landowners adjacent to Nicasio and Halleck Creeks and in other areas around Nicasio Reservoir.  

  3. 45 years ago, Marin Water rejected a nearly identical spillway modification project due to flooding impacts.  
    In 1980, Marin Water considered a similar proposal (install a rubber dam across the Nicasio spillway, creating roughly 4,000 acre-feet of storage) to raise Nicasio Dam.  The District     did not implement the 1980 project due to the severe flooding impacts on Nicasio including the need to acquire through eminent domain at least four residences.  

If the Nicasio Spillway Modification Project was not considered implementable in 1980, recent flooding conditions in Nicasio underscore that the Project is not implementable now.

Our Position

We understand that Marin Water’s intent is to increase the resilience of its water supplies, but this goal must be balanced with consideration of serious impacts that raising Nicasio Reservoir will have on our properties and community, especially in light of the flooding that currently occurs along Nicasio and Halleck Creeks.

We oppose a project to raise the Nicasio Reservoir that will inundate, flood or otherwise harm our historic school, private properties, roads, or upstream/downstream environmental resources.  

Further, Marin Water must address current flooding of our Nicasio Community related to poor maintenance and sediment build-up in the creeks where water flows into Nicasio Reservoir.

Marin Water has other options to increase the resilience of its water supplies without harming our Nicasio Community, including the expansion of its Kent Lake Reservoir.


NLOA Principles for Addressing the Proposed Nicasio Reservoir Spillway Modification Project

  • Our NLOA commitment is, to the best of our ability, to protect our Nicasio Community from ongoing and additional harm.

  • We will work with Marin Water to determine if there are shared solutions for Nicasio Reservoir that satisfy our core principle that Nicasio’s historic school, private properties, roads and upstream/downstream environmental resources are not inundated, flooded, or otherwise harmed by the Nicasio Reservoir Spillway Modification Project.  

  •  We will not accept proposed solutions that trade off harm to our historic school, private properties, roads and upstream/downstream environmental resources for other benefits.

What you can do to help

1) Write a letter
to MMWD

2) Attend a meeting

2) Volunteer & donate
to help NLOA

Public Comment Period runs from April 30 until August 4, 2025 for citizen’s to voice their concerns regarding the proposed plan to raise the Nicasio Dam Spillway and level of the Nicasio Reservoir. Comments must be submitted before August 4, 5:00pm in one of the following ways:

  1. By email to: Click here to send an email directly to Marin Water

  2. Or by U.S. postal mail to:
    Marin Water
    Attention: Elysha Irish
    220 Nellen Ave.
    Corte Madera, CA 94925

As part of the environmental review process, Marin Water is holding two public meetings. These meetings are an opportunity for interested parties to learn more about the project and provide public comments. The information presented will be the same for both meetings.

If you’d like to get more involved, the NLOA has several initiatives that we’d love help with, including raising funds to help pay for professional & legal consultants that we are working with to help support our position.

> Email NLOA to get involved!