NewsDrop July 2023

Figure 2.

Phase II effectively began with cycle-1 testing in October 2020 and is projected to extend through 2024. ASR cycle testing is a long-term testing plan in which about 10% of the planned total storage volume is injected in stages which are followed by subsequent periods of withdrawal. For the NBU-ASR project, there are three planned cycles, each completed within approximately one calendar year. The cycle testing process for the NBU-ASR project will end with cycle-3 recovery and will ideally result in an established freshwater “bubble” in the target storage zone with a surrounding buffer of mixed water. Cycle-3 recharge began in January 2023. To date, the aquifer has responded to cycle-testing as expected based on historical data and hydraulic response modeling. Phase III (the ASR Project Expansion Phase) will begin no earlier than January 2026 and would involve expansion into a full-scale ASR facility. Monitoring of the Aquifer system and the NBU-ASR, which was implemented at the start of Phase II, will be maintained through the end of testing and beyond if the project is fully developed. Distinguishing between system-wide (non-ASR) changes and ASR-related changes in the Aquifer is critical to effectively monitoring and mitigating potential adverse impacts to the freshwater zone and Comal Springs.

The EAA and NBU have worked collaboratively to establish a monitoring strategy that accounts for non-ASR pressure changes so that potential ASR-related problems can be identified, while non-ASR-related effects do not hinder operations by triggering unwarranted mitigation responses. The two main components relevant to the NBU-ASR monitoring program are water levels and water quality. Sensitive water quality and pressure parameters with known temporal stability are monitored in near real-time. Thus, the monitoring system is capable of indicating aquifer system changes with enough time to effectively implement any needed mitigation measures. The near real time water level and conductivity monitoring is supplemented with annual to bi-annual water quality sampling of monitoring wells. The EAA encourages a wide range of aquifer management and conservation strategies to enable sustainable management of the Edwards Aquifer. Evaluation and development of the NBU-ASR is ongoing and the EAA will continue to provide regulatory oversight and work collaboratively with NBU as they conscientiously develop and explore alternate supply sources in support of long-term water management objectives.

THE EAA ENCOURAGES A WIDE RANGE OF AQUIFER MANAGEMENT AND CONSERVATION STRATEGIES TO ENABLE SUSTAINABLE MANAGEMENT OF THE EDWARDS AQUIFER.

NBU’s first ASR well.

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