Calleguas initiates court-ordered 'ground rules' study for ASR operations

Calleguas initiates court-ordered 'ground rules' study for ASR operationsA specialized study group has begun work on a binding operational plan for the district’s Las Posas Aquifer Storage and Recovery well field following a 2023 legal judgment.

A study group comprising the district, Fox Canyon GMA, and landowners will define operational parameters for the Las Posas ASR project.

The process stems from a July 2023 judgment and is expected to take 12 to 18 months.

The final Project Operation Plan will be submitted directly to the court for approval, bypassing standard public review.

Staff are utilizing current imported water shutdowns to gather dynamic data on well injection and drawdown rates.

The Calleguas Municipal Water District has convened a study group to establish what staff termed "ground rules for groundwater" regarding the future operation of its Las Posas Aquifer Storage and Recovery (ASR) well field. Following a judgment signed in July 2023, the district is collaborating with the Fox Canyon Groundwater Management Agency and a landowner representative to define operational parameters for the facility. District staff described the initiative as foundational for the future strategic use of the asset, a system of 18 dual-purpose wells developed in the 2000s with a storage capacity of up to 50,000 acre-feet. The study group is tasked with understanding potential impacts on nearby wells and developing recommendations to avoid or mitigate them. Unlike typical planning procedures, the resulting Project Operation Plan will be submitted directly to the court for approval. Staff noted that while parties to the judgment may object, the document will not undergo a standard public review and comment period. The development of the plan is expected to take between 12 and 18 months. Once the judge approves the plan, the district will operate the well field under the defined parameters to bolster local drought and emergency reliability. In the interim, the district is utilizing planned imported water shutdowns to collect dynamic data on well injection and discharge rates to inform the study. Staff highlighted that a major "stress test" conducted in the fall of 2022 extracted approximately 4,000 acre-feet over four months, providing a data baseline for the new operational models. During current operations related to a Metropolitan Water District shutdown, the district reported producing approximately 15 cubic feet per second (cfs) at the well field, alongside 25 cfs from the treatment plant.