A Roadmap to Water Resilience for Marin Municipal Water District June 13, 2022

The prospect of Marin Municipal Water District’s reservoirs running dry within a year shows that the District has fallen short in its efforts to ensure a long-term resilient supply of water for its customers. The District and its ratepayers are vulnerable to the increasing likelihood of water shortfalls.

Due to a failure to fully develop and act on long-term water resilience plans, Marin Municipal Water District left itself with only the expensive Richmond Bridge pipeline 41 U.S. Congress, “H.R. 3684 - Infrastructure Investment and Jobs Act,” 117th Congress (2021-2022). https://www.congress.gov/bill/117th-congress/house-bill/3684/text option for responding to the drought emergency, which could have preempted pursuit of other means of establishing long-term water resilience.

Marin Municipal Water District has not adequately addressed climate change in developing its long-term water supply plans to date. Relying on historical data to predict future rainfall is not sufficient given ongoing and future changes in the climate.

Even with ongoing successful conservation efforts, Marin Municipal Water District will need additional sources of water and storage capacity to provide a long-term reliable water supply for its ratepayers.

Marin Municipal Water District has been slow to adopt proven Advanced Metering Infrastructure technology, which could enhance conservation by providing the District and its customers with real time data on water use and repairable leaks.

Marin Municipal Water District could enhance its water resilience by constructing an East Bay pipeline for importing additional water. This option would also enable MMWD to participate in a regional desalination project and add storage capacity in the Los Vaqueros Reservoir.

Marin Municipal Water District could improve its water supply resilience by restructuring its relationship with the Sonoma County Water Agency in order to increase imports and potentially develop additional storage capacity.

Drought-proof supplies of water will become increasingly important in the coming years, with climate change-induced droughts expected to become more frequent and severe.

Marin Municipal Water District has failed to place sufficient priority on development of drought-proof sources of water, such as recycling programs and regional desalination projects.

The use of direct potable reuse presents a reliable, drought-proof, and cost-effective option for securing a substantial volume of additional potable water from within the Marin Municipal Water District.

The use of direct potable reuse is a potentially more efficient and impactful use of wastewater, as compared to recycling that wastewater for non-potable use in a “purple pipe” system.

Desalination is a feasible, drought-proof option for producing additional water for the Marin Municipal Water District.

Marin Municipal Water District participation in a large-scale regional desalination project is likely the most feasible desalination option that could provide an additional drought- proof source of water.

The measures needed to secure long-term water resilience will require additional funding and higher water rates for Marin Municipal Water District’s ratepayers.

Marin Municipal Water District would improve its chances of receiving federal and state water resilience grant money by participating in regional partnerships.

Marin Municipal Water District could significantly enhance water supply resilience and improve risk management during droughts, earthquakes, and other natural disasters by increasing its participation in regional partnerships with other water agencies.