About Stormwater Capture
Stormwater capture is the process of retaining stormwater for beneficial use, such as groundwater recharge, flood mitigation, and water quality enhancement. Stormwater capture can be done on a variety of scales, ranging from the household scale—through redirecting downspouts and the use of rain gardens—to infrastructure projects such as large recharge basins and injection wells.
Soquel Creek Water District has kept stormwater capture as one of the multiple supplemental supply options it is considering to mitigate aquifer depletion and seawater intrusion. Key factors that influence stormwater capture feasibility include stormwater availability, water quality, soil and geologic conditions, and land availability and ownership.
In partnership with the County of Santa Cruz, Soquel Creek Water District investigated the feasibility of stormwater capture and recharge within the District’s service area.
Based on years of regional and site-specific investigation, the District has identified the following key challenges to implementing large-scale stormwater capture:
Suitability: Research conducted by the Santa Cruz County Resource Conservation District and UCSC’s Hydrogeology Group determined that much of the groundwater basin underlying the District service area is not highly suitable for aquifer recharge due to geologic and topographic properties.
Reliability: Stormwater volumes are extremely variable, and even in wet years, the volume that is able to be recharged back into the aquifer is limited compared to the relative volume of water needed to reach sustainability.
Water Quality: Stormwater is only as clean as the surfaces it flows over. Contaminants such as metals, pesticides, and hydrocarbons are consistently found in urban stormwater. Treatment of stormwater would be required to prevent the contamination of our aquifer.
Scalability: Preliminary investigations indicate that the number of potential sites with large volumes of available stormwater for capture and recharge-suitable subsurface conditions are limited.
Given the other available supplemental supply options the District is pursuing, such as Pure Water Soquel and surface water transfers, the District is not actively pursuing stormwater capture at this time.
Small-Scale Stormwater Capture
Small-scale stormwater capture, such as at the household level, is encouraged. The District offers rebates for rainwater catchment, downspout redirects, and other landscape transformations.
The Santa Cruz County Resource Conservation District 'Slow it, Spread it, Sink it!' Guide provides an overview of the design considerations for rainfall-catching devices like rain barrels, swales, and rain gardens.
Stormwater capture is being pursued in more suitable locations in the Santa Cruz region. The Santa Cruz County Resource Conservation District has additional information on their Manage Aquifer Recharge program website page.