Desalination Executable Solution and Logistics Plan (DESAL Plan)

The San Luis Obispo County Flood Control and Water Conservation District (District) is kicking off Phase 1 of a 5-Phase effort to identify and implement a local desalination project. Desalination, the process of removing salt from seawater and/or brackish water to create a freshwater resource, can provide a safe, long-term, drought-proof, and resilient water supply.

Timeline

Desalination projects take time to plan, permit, and construct. Factors that contribute to the feasibility of a desalination project are permitting, funding, community support, and environmental protection. The County has coordinated with the Countywide Water Action Team (CWAT), an informal working group of staff from entities across the county with water supply planning responsibilities, to create a 5-phased approach to develop a desalination project. 

In Phase 1: DESAL Plan Agreement Phase, the County worked with local agencies to establish participation, develop an initial planning scope, launch stakeholder outreach, and pursue funding opportunities. Right now, in collaboration with partner agencies and with support from a U.S. Bureau of Reclamation WaterSMART grant, the District is in Phase 2: DESAL Plan Development Phase; this phase focuses on preparing a comprehensive Feasibility Study to evaluate and compare desalination project alternatives. The goal of this effort is to identify the most viable desalination project(s) for potential advancement by partner agencies to help meet the region's long-term water supply goals. 

For a draft timeline and description of the 5-phases, please click on the following figure:

The following agencies have adopted resolutions agreeing to be considered in the DESAL Plan:

  • City of Arroyo Grande
  • Atascadero Mutual Water Co.
  • Avila Beach CSD
  • Cambria CSD
  • Golden State Water Co.
  • City of Grover Beach
  • Los Osos CSD
  • City of Morro Bay
  • Nipomo CSD
  • Oceano CSD
  • City of Paso Robles
  • City of Pismo Beach
  • San Miguel CSD
  • Santa Barbara County
  • City of San Luis Obispo
  • Templeton CSD

Join our Mailing List

  • Click here to join the County of San Luis Obispo's DESAL Plan mailing list.

Submit a Public Comment

  • Click here to fill out a public comment form on the DESAL Plan, draft documents, or to share general feedback on the desalination planning effort. 

Updates


Events and Community Outreach

Recent desalination projects within the state of California have taught us that stakeholder outreach and early engagement are critical to a successful desalination project. Engagement in the early planning phases of the project will allow us to build a broad coalition of supporters, which will be necessary to obtain the required permitting. 

Updates on the desalination planning effort will be given as part of the Water Resources Advisory Committee (WRAC) Ongoing Updates. WRAC meetings are open to the public. For meeting dates and locations, please go to www.slocounty.ca.gov/Departments/Public-Works/Committees-Programs/Water-Resources-Advisory-Committee-(WRAC).aspx

  • Recent & upcoming DESAL Plan WRAC items can be viewed at the links below:

FAQs

Desalination is the process of removing salt from water. There are multiple desalination technologies, including thermal distillation, electrodialysis, capacitive deionization, and membrane separation (reverse osmosis). Desalinated water can serve as a new water source to meet the demands placed on existing municipal supply, agricultural/landscape irrigation, groundwater replenishment, and seawater intrusion mitigation.

In the county, existing conditions and future projections indicate that water security is declining as demands increase and available supplies and their reliability decrease.

The County has implemented / planned for water supply strategies including conservation, stormwater capture, Nacimiento Water Project optimization, Lopez Water Project, Salinas Dam transfer and spillway rise, State Water Project and Water Management Tools, recycled water, produced water from oil extraction, cloudseeding, and regional resiliency. These efforts will help extend the County’s water supply, but they are not enough to overcome long-term shortages. Competition for existing water supplies (particularly those that depend on precipitation) in the County and across the state, is anticipated to increase with new regulations related to groundwater/surface water interactions and minimum sustainability thresholds, water quality, environmental flow, and housing directives. Relying on water sourced from precipitation from outside San Luis Obispo County is challenging due to the County’s relative geographic isolation, energy, right-of-way requirements, and fluctuating supply year to year. A new drought-proof, local water supply will be necessary to sustain the population long-term, and with the County’s 90-mile coastline, desalination is a realistic goal.

Efforts for preliminary desalination planning were included in the District’s fiscal year 2022-23 budget where water resiliency was named a top priority. The board authorized staff to proceed with a DESAL Plan on October 18, 2022, and staff will return to the board at a future date (anticipated April 18, 2023) with a proposed scope of work for a consultant and the estimated costs associated with DESAL Plan development.  Estimating costs associated with building and maintaining a project and how it will be funded is a part of the DESAL Plan development process.

Grants are, and will continue to be, pursued to offset project costs throughout all DESAL Plan phases. The grant application for the USBR's WaterSMART: Water Recycling and Desalination Planning grant is available here and USBR's anticipated awards, including $548,410 to the County, are listed here.

 

Although a seawater desalination project has the potential to be situated at a variety of locations along approximately 90-miles of coastline within the County, careful consideration of factors such as appropriate land use, location of sensitive and protective areas (e.g., National Marine Sanctuaries), siting concerns related to the coastal zone, and proximity to power and piping infrastructure would narrow the feasible locations. The project location, size, water production, technology to be used, etc. will be decided during Phase 2.

The best available technology and methods to meet regulations and mitigate environmental impacts will be vetted during Phase 2. There are several technologies available to protect marine life, and it is anticipated that they will continue to evolve during the planning phase along with guidance from the state and regulatory agencies.

County board items related to desalination can be viewed at the links below: