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Strategic Water Supply Roadmap

Improving our water supply reliability in the face of climate change

Severe conditions brought on by the drought over the past several years have intensified the District’s focus on strengthening the reliability of its water supply. Starting in February 2022, the District’s Strategic Water Supply Assessment evaluated the District’s current baseline water supply in the context of climate-change-driven droughts and the impact of potential future water management alternatives that could improve the District’s long term water supply resiliency. This yearlong effort helped the District prioritize which options to pursue as part of the integrated Roadmap.  

Water Supply Roadmap

Approved Tuesday, Feb. 28, 2023, by the Marin Water Board of Directors, the District's water supply roadmap combines a mix of short-term water supply strategies with pre-design work to support medium- and longer-term options. The integrated roadmap has five main elements.

Elements of Water Supply Roadmap:

Water Conservation Element (near-term) 

  • Build upon the District's industry-leading conservation program and pursue a variety of identified activities to incentivize further water use efficiency. 

Water Shortage Contingency Plan (completed) 

  • The District’s approved WSCP is ready to be implemented as needed should water supply conditions warrant.  

Electrify Lake Soulajule (near-term) 

  • This measure provides PG&E line power to the pump station at Lake Soulajule so that the lake can be operated more frequently.  

  • Estimated water yield: 420 AFY.  

  • Estimated cost: $6 million 

  • Cost per AF: $1,800. 

Phoenix-Bon Tempe Connection (near-term) 

  • This project installs a connection from Phoenix Lake to Bon Tempe reservoir, increasing District control over water flows.  

  • Estimated water yield: 260 AFY 

  • Estimated cost: $5 million  

  • Cost per AF: $1,611 

Forecasting and Stream Release Automation (near term) 

  • This initiative aims to improve forecasting capabilities and stream release automation to better manage releases. 

Operational Strategy for Maximizing Sonoma Water supply (near-term) 

  • Develops operational rules to guide the timing and quantity of water purchased from Sonoma to maximize take of supplemental water in dry years while minimizing risk of reservoirs spills.  

Dedicated Conveyance (medium-term) 

  • Develop dedicated conveyance to storage in two phases.  

  • Phase 1 – Stafford Lake to Soulajule/Nicasio  

  • Phase 2 – North Marin Aqueduct to Stafford Lake 

  • Estimated water yield:  3,000-3,150 acre-feet 

  • Estimated cost: $111-$158 million 

Improve Existing Conveyance (medium-term) 

  • Improve conveyance of water to Marin Water system via South Transmission System and possible Kastania Pump Station expansion.  

Raising Dams (long-term) 

  • Develop an additional storage via movable spillway or raising of dams at Kent, Nicasio or Soulajule reservoirs.  

  • Estimated yield: 5,000 acre-feet 

  • Estimated cost: $90 million 

Increase Storage via Regional Partnerships (long-term) 

  • Pumping existing groundwater from the Santa Rosa Plain aquifer for consumption could create the necessary capacity to store winter water from Sonoma County.  

Petaluma Brackish Desalination (near-term) 

  • Monitor advances in desalination technology, track installation of desalination plants in California and perform feasibility analysis for Petaluma brackish desalination which could conceptually yield 5,000 acre-feet.  

Recycled Water Expansion (near-term) 

  • Pursue grant opportunities for recycled water projects to reduce the cost to the average cost.  


This strategy is based on the Strategic Water Supply Assessment developed by District consultant Jacobs Engineering. More information on the assessment and the final draft report are linked below.


Strategic Water Supply Assessment Final Draft Report (May 2023)

This report was prepared by Jacobs Engineering, with review by Marin Water staff.


Background Information on the Strategic Water Supply Assessment

Goals of the Assessment

The District has initiated a strategic assessment of various water management alternatives that could support community water needs in times of future shortages. The effort is intended to:

  1. Build on extensive previous water supply planning efforts and incorporate new options
  2. Evaluate current risk to District’s water delivery reliability under recent and future extended drought scenarios
  3. Determine a timeline for developing alternative water management options to maintain resiliency
Projects included in Assessment
  • Water Transfers with Conveyance through Bay Interties
  • Sonoma-Marin Partnerships 
  • Local Supply Enhancements
  • Desalination
  • Recycled Water
  • Water Conservation
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