Martha Way Well Aquifer Storage and Recovery Pilot Test

The Santa Rosa Plain Groundwater Sustainability Agency (GSA), in partnership with the City of Santa Rosa Water Department (Santa Rosa Water), will conduct a pilot test at an existing well on Martha Way to evaluate the feasibility of storing and recovering drinking water in the underground aquifer. This process is known as Aquifer Storage and Recovery (ASR), which you can learn more about here. The purpose of the project is to gather valuable information about the viability of ASR as a tool to sustainably manage our local water supply—especially during droughts, emergencies, or peak demand periods. The project consists of temporarily adding ASR capabilities to the existing well to recharge water from Santa Rosa Water’s drinking water supply into the underground aquifer system. Approximately 2.26 million gallons of drinking water were recharged into the aquifer and stored, and 2.52 million gallons were recovered via the Martha Way well.

Project Location

This pilot test was conducted at the Martha Way well, near the intersection of Martha Way and Albert Drive and adjacent to the Santa Rosa Southeast Greenway.

Project Timeline

Construction is anticipated to start in the second or third week of July and be completed in October 2025. Daily work hours will be weekdays 8am-6pm and only on weekends if necessary with advanced notice.

1. Mid July 2025: Equipment Installation –The pump, generator, piping, fencing, and monitoring systems were installed.
2. September 2025: ASR pilot began.
3. September – December 2025: Testing Phase – Three ASR cycles completed while collecting groundwater and water quality monitoring data.
4. December 2025 – May 2026: Data analysis and final reporting.

Project Results

Three ASR test cycles were conducted, each involving water injection (recharge), a storage period, and water recovery. Each cycle increased in duration, with the final cycle including 11 days of recharge and 5 days of recovery. The depth to groundwater was approximately 34 feet below ground surface prior to the ASR pilot test, and pilot operations helped raise groundwater levels to 26 feet below ground surface.

During the pilot, the overall water quality characteristics at the Martha Way Well changed as expected. Stored water was a mixture of native groundwater which is high in iron and manganese, and the added drinking water which had low or absent levels of iron and manganese. Iron and manganese concentrations were lower in recovered water than native groundwater conditions but were still close to the secondary maximum contaminant loads.

Results show that ASR at the Martha Way well is hydraulically feasible, but the consultant team recommends additional construction and testing to ensure it can meet local needs in the future.

Read the full technical report here.

Project Funding

The ASR pilot test is funded through a grant issued from the California Department of Water Resources (DWR). Results from the pilot test will inform the Santa Rosa Plain GSA and the City of Santa Rosa in considering ASR and regional water banking opportunities.

Contact Us

If you have any questions about the project, please contact: City of Santa Rosa Project Manager: Claire Nordlie, 707-543-3962, cnordlie@srcity.org GSA Project Manager: Indigo Bannister, 707-304-7313, ibannister@westyost.com