GSI is helping the City of Woodland, California, develop its aquifer storage and recovery (ASR) system.


The City wants to convert its primary potable water supply source from groundwater to surface water from the Sacramento River. During periods of lower demand (winter months), unused treated surface water will be recharged into the aquifer for storage. During periods of high demand (summer months), the recharged water will be extracted, dosed with hypochlorite solution, and conveyed to the City’s distribution system.

GSI’s Solution

Working with Carollo Engineers, GSI is providing hydrogeologic services for design and installation of two ASR wells, two monitoring wells, and two well abandonments. The objective of the project is to store treated surface water to improve the reliability of summer pumping and improve the quality of pumped water. Current work includes:

  • Leading the design, permitting, and construction oversight of the wells.
  • Drilling each well to approximately 600 feet and will have a recovery capacity of 2 million gallons per day.
  • If an adequate amount of treated surface water is available, planning and implementing an interim injection program after the wells are drilled and tested. Temporary injection equipment will be installed as the aboveground pumping and injection system is being designed to begin developing the target storage volume.
  • After the wellhead improvements are completed, the well should be able to immediately begin recovery of high quality water.
  • Future phases of the project will include pilot testing and possibly expanding the ASR program.