Pendleton ASR Program

The City of Pendleton owns and operates five high-capacity ASR wells that are used to recharge and store excess treated surface water from the Umatilla River in the basalt aquifer system. The City operates its ASR system to meet summer demands on their water system, reduce declining groundwater levels, and increase the long-term reliability of other City wells. GSI provides ongoing support for the City’s ASR program, including evaluating well performance, tracking the aquifer’s hydraulic response to ASR activities, monitoring long-term groundwater level trends, and assessing the quality of water recovered from storage at each ASR well. GSI also assists with preparing and submitting annual pilot testing reports to state regulatory agencies and monitors compliance with the City’s ASR limited license permit.

Pilot testing of the ASR system has shown positive results and demonstrates that the system is capable of storing and recovering more than 800 million gallons of high-quality drinking water annually. The City’s ASR program is the largest operating program in the Pacific Northwest and has been successful in its overall benefit to help the City meet increasing demands on its water system and improve the sustainability of the region’s groundwater supply.

GSI’s work has involved:

• Ongoing support for pilot testing of the City’s ASR program
• Limited license modifications to add new wells to the ASR system
• Geochemical compatibility assessments
• Annual reporting and interfacing with regulatory agencies