Tracer Test Planning For Groundwater Replenishment With Recycled Water In The San Fernando Basin For The City Of Los Angeles

This project focuses on developing a regulatory-compliant tracer test plan for the Hansen Spreading Grounds in the San Fernando Basin to support groundwater replenishment with purified recycled water. Led in partnership with the Los Angeles Department of Water and Power (LADWP), the study aims to confirm underground retention time and groundwater travel paths from the spreading facility to nearby production wells, in alignment with California’s Indirect Potable Reuse (IPR) requirements. Building upon foundational work from WRF Project 5016, it incorporates updated hydrogeologic modeling and tracer selection strategies tailored to current site conditions. The outcomes of this project will provide critical inputs to LADWP’s IPR permitting process while also offering a valuable, real-world demonstration of practical tracer testing methodologies applicable to groundwater recharge operations across the industry.