Legislation Details

File #: 2026-0900   
Type: Consent Calendar Item Status: Agenda Ready
File created: 7/30/2026 In control: Sonoma County Water Agency
On agenda: 9/15/2026 Final action:
Title: Advanced Quantitative Precipitation Information C-band Radar Cost Reimbursement Agreements
Department or Agency Name(s): Sonoma County Water Agency
Attachments: 1. Summary Report, 2. Attachment 1 - Draft Advanced Quantitative Precipitation Information C-Band Cost Reimbursment Agreement, 3. Attachment 2 - Draft Advanced Quantitative Precipitation Information C-Band Deployment Cost Agreement, 4. Attachment 3 - Prior Board Actions
Related files: 2021-0252, 2023-0256, 2024-1274, 2025-0555

To: Board of Directors, Sonoma County Water Agency

Department or Agency Name(s): Sonoma County Water Agency

Staff Name and Phone Number: Brad Sherwood 707 547-1927, Dale Roberts 707-547-1979

Vote Requirement: Majority

Supervisorial District(s): All

 

Title:

Title

Advanced Quantitative Precipitation Information C-band Radar Cost Reimbursement Agreements

End

 

Recommended Action:

Recommended action

Authorize Sonoma County Water Agency’s General Manager to execute two Advanced Quantitative Precipitation Information System cost reimbursement agreements with eight San Francisco Bay Area water, wastewater, and flood control districts in substantially the form as the draft presented to this Board.  The agreements would reimburse Sonoma Water $300,000 from bay area partners who participated in the Advanced Quantitative Precipitation Information project for implementing the deployment of the C-band weather radar at Mount Barnabe near Lagunitas, California.

end

 

Executive Summary:

This item presents for consideration and approval two separate agreements that would allow eight San Francisco Bay Area water, wastewater, and flood control entities, including Alameda County Water District, East Bay Dischargers Authority, Central Contra Costa Sanitary District, Contra Costa County Flood Control District, Alameda County Flood Control District, Zone 7 Water Agency, City and County of San Francisco by and through its Public Utilities Commission and Santa Clara Valley Water District participating in the project to reimburse Sonoma Water for funding capital expenses to deploy the largest weather radar in the AQPI Project at Mount Barnabe near Lagunitas in Marin County.

 

The purpose of the AQPI Project is to provide more precise rainfall forecasting for atmospheric rivers, which will give flood control managers, including Sonoma Water, emergency responders, transportation officials, and media outlets more precise information on the location, timing, and intensity of expected rainfall.

 

Discussion:

For more than 15 years, Sonoma Water and several other agencies in the Bay Area have collaborated with the National Oceanic and Atmospheric Administration, Colorado State University’s Cooperative Institute for Research in the Atmosphere, the United States Geological Survey - Pacific Coast and Marine Science Center, and the Center for Western Weather and Water Extremes at Scripps Institute of Oceanography, to develop a regional project called the “San Francisco Bay Area Advanced Quantitative Precipitation Information System” (AQPI Project).

 

The AQPI Project is a multi-year effort to provide improved precipitation and hydrologic information to water agencies, flood control agencies, wastewater agencies, and other entities in the San Francisco Bay area to assist in mitigating flood hazards, maximizing water supply, improving emergency response times, and enhancing ecosystem services.

 

The AQPI Project included deployment of four X-Band radars throughout the region and a single C-Band radar with a goal of improving short-term (48-hour) monitoring and prediction of high-impact rainfall events.

 

Sonoma County Water Agency was awarded $19.84 million in funds in August 2016 from the Department of Water Resources statewide Proposition 84 (The Safe Drinking Water, Water Quality and Supply, Flood Control, River and Coastal Protection Bond Act of 2006) grant to implement the San Francisco Bay Area Advanced Quantitative Precipitation Information System project. Costs incurred by Sonoma Water in implementing the AQPI Project will be partly reimbursed with these grant funds.

 

The C-Band radar equipment on Mt. Barnabe was grant funded. The structural and electrical infrastructure needed for the radar were not grant funded but funded by Sonoma Water. Sonoma Water has negotiated other San Francisco Bay Area water, flood, wastewater, and emergency managers to reimburse Sonoma Water for most of its capital expenses.

 

The installation of the C-Band radar on Mt. Barnabe was critical to the success of the AQPI Project since having a weather radar cover the region offshore of Marin, Sonoma, and Mendocino counties greatly enhances situational awareness of the severity of incoming precipitation events and helps forecasters more precisely determine where atmospheric rivers will make landfall, as well as the elevation, speed, width, and direction of travel of atmospheric rivers. This offshore region is "upstream" of the Bay Area and is often the path of extreme precipitation from the Pacific Ocean to the greater San Francisco region. Further, the National Weather Service NEXRAD radar network cannot observe precipitation well in this offshore area. The Mt. Barnabe C-Band radar's detection of precipitation in the lower elevations typical of atmospheric rivers would remedy a blind spot of the NEXRAD radar network.

 

This item presents for consideration and approval two agreements that allow eight San Francisco Bay Area water, wastewater, and flood control agencies, including Alameda County Water District, East Bay Dischargers Authority, Central Contra Costa Sanitary District, Contra Costa County Flood Control District, Alameda County Flood Control District, Zone 7 Water Agency, City and County of San Francisco by and through its Public Utilities Commission and Santa Clara Valley Water District to reimburse Sonoma Water for capital expenses spent to design, manage, and deploy the C-band weather radar for the AQPI Project.

 

County of Sonoma Strategic Plan:

This item directly supports the County’s Five-year Strategic Plan and is aligned with the following pillar, goal, and objective.

Pillar: Resilient Infrastructure

Goal: Goal 5: Support, fund, and expand flood protection.

Objective 1: Develop partnerships with cities, tribal governments, and private organizations regarding flood protection and sustainability to identify gaps and address climate change impacts.

 

The AQPI Project supports Sonoma County’s efforts to partner with other local entities to prepare, mitigate, and prevent community impacts caused by emergencies and natural disasters including, but not limited to, flood protection and other adverse effects from heavy precipitation events.

 

Sonoma Water Strategic Plan Alignment

This item directly supports Sonoma Water’s Strategic Plan and is aligned with the following goal, strategy, and action item.

 

Goal: 5. Climate Change - Assess risk and uncertainty of climate change and develop and take actions that improve resiliency and sustainability.

Strategy: 5.1 Develop and implement practices to understand and minimize vulnerability to climate change impacts.

Action Item: 5.1.2 Support interagency partnership efforts addressing regional climate-resiliency planning and projects.

 

The AQPI Project supports Sonoma Water’s efforts to partner with other agencies to respond and adapt to the effect’s climate change is having on precipitation patterns in the region, as well as improve early warning capabilities to avoid life-safety threats from potential land sliding, debris flows, flooding, erosion, road hazards, and burn scar problems that could be compounded from heavy rain events.

 

Racial Equity:

 

Was this item identified as an opportunity to apply the Racial Equity Toolkit?

No

 

Prior Board Actions:

See attachment 3

 

Fiscal Summary

 Expenditures

FY26-27 Adopted

FY27-28 Projected

FY28-29 Projected

Budgeted Expenses

 

 

 

Additional Appropriation Requested

 

 

 

Total Expenditures

 

 

 

Funding Sources

 

 

 

General Fund/WA GF

 

 

 

State/Federal

 

 

 

Fees/Other

$300,000

 

 

Use of Fund Balance

 

 

 

General Fund Contingencies

 

 

 

Total Sources

$300,000

 

 

 

Narrative Explanation of Fiscal Impacts:

Sonoma Water’s General Fund will be reimbursed $300,000 from bay area partners who participated in the Advanced Quantitative Precipitation Information project for implementing the deployment of the C-band weather radar at Mount Barnabe. No additional appropriations are required.

 

Staffing Impacts:

 

 

 

Position Title (Payroll Classification)

Monthly Salary Range (A-I Step)

Additions (Number)

Deletions (Number)

 

 

 

 

 

 

 

 

 

 

 

 

 

Narrative Explanation of Staffing Impacts (If Required):

N/A

 

Attachments:

Attachment 1: Draft Advanced Quantitative Precipitation Information C-band Cost Reimbursement Agreement

Attachment 2: Draft Advanced Quantitative Precipitation Information C-band Deployment Cost Agreement

Attachment 3: Prior Board Action Items

 

Related Items “On File” with the Clerk of the Board:

None.