Marin Voice: MMWD director details response to county water supply crisis

While 95% of the rest of the state remains in severe drought, Marin’s seven reservoirs are now at more than 100% of normal storage.

In spite of our temporary reprieve, Marin needs to continue to brace for climate change. Here is what the Marin Municipal Water District is doing to bolster the water supply, build climate resilience and meet the Marin Civil Grand Jury’s recommendation to increase supplies by 10,000 to 15,000 acre-feet.

In January, Marin Water renovated the Kastania Pump Station, south of Petaluma, on time and on budget. This unheralded regional achievement expands Marin Water’s capacity to import an additional 5,000 acre-feet of “winter water” from the Russian River. This increase is equivalent to the size of Bon Tempe Reservoir.

In early 2021, we added another 4,000 acre-feet of supply by rebuilding a state-of-the-art recycled water plant in partnership with Las Gallinas Sanitary District. This 400% increase in production is now being used for landscapes, gardens and other non-potable uses in our San Rafael “purple pipe” district. A planned project to extend a recycled-water pipeline to Peacock Gap is also underway.

We are also in the process of redesigning our Phoenix Lake transmission system. This improvement could add up to 1,000 acre-feet of water to our supply portfolio from this previously underperforming asset.

Our ongoing water supply assessment process is reviewing the feasibility of all options. Expanding local reservoir storage with installation of cost-effective spillway gates at Nicasio and Kent reservoirs could provide a significant increase in local supply with the flexibility to release water for habitat needs. Improved water recycling at the Central Marin Sanitary Agency could provide the San Quentin State Prison with the ability to flush toilets for 4,000 inmates.

Recognizing that desalination could supplement rainfall in drought years, we are also carefully reviewing several potential scenarios. One possible location near the Petaluma River brackish water aquifer shows promise as a shared regional plant that may avoid some of the environmental pitfalls of other locations.  Desalination requires a vote of Marin residents and it remains to be seen whether it would be affordable and equitable for our customers — 70% of whom are Tier 1 water users.

As water supplies were declining in 2021, Marin Water created an emergency plan for a pipeline on the Richmond-San Rafael Bridge. Pipes and pumps were acquired, and negotiations for water rights were underway when adequate rainfall ended our emergency status.

We are continuing the mandatory environmental review process to determine whether the estimated $100 million bridge pipeline is an acceptable option.

Improved conservation and efficiency efforts also need to play an important role in climate change resilience because every gallon saved bolsters supply. In response to last year’s drought, we expanded water-saving incentives for residents – including rebates for turf replacement, gray water systems, rainwater catchment and pool covers. Marin residents reaffirmed their historic commitment to living within their means and achieved a peak 40% savings in water use.

They deserve our gratitude and appreciation for their efforts.

Generous rebates also led to the widespread adoption of the Flume smartphone monitor by Marin residents. It provides instant leak detection and realtime household water use data. At the same time, Marin Water has long employed a systemwide leak detection program to identify and replace leak-prone pipes from our 900-mile transmission system.

Threat of wildfire is the climate change bookend for Marin’s water supply challenges. Wildfire is a grave threat to the health of our Mount Tamalpais watershed, water quality and public safety.

In response, Marin Water implemented a robust, herbicide free, vegetation management program. Reducing ladder fuels and brush reduces wildfire risk and can increase surface water flow into our reservoirs.

Last year, our crews completed more than 1,000 acres of watershed lands. We are also continuously improving our approach to wildfire risk by utilizing evolving forestry management practices.

Ultimately, Marin needs to take a holistic approach to water supply to meet the challenges that climate change presents. Conservation, increased supply resiliency and watershed stewardship are complementary pieces of the climate change puzzle that our community will need to solve together to ensure our water future.

Larry Bragman, of Fairfax, represents District 3 on the Marin Municipal Water District Board of Directors.