COMMITTEE AGENDA MEMORANDUM
Water Supply and Demand Management Committee
Government Code ? 84308 Applies: Yes ? No ?
(If "YES" Complete Attachment A - Gov. Code ? 84308)
SUBJECT: title
Receive and Discuss Information regarding the Status and Potential of Various Groundwater Banking Projects.
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RECOMMENDATION: Recommendation
Receive and discuss information regarding the status and potential of various groundwater banking projects.
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SUMMARY:
Valley Water's groundwater banking program has played a vital role in managing the County's excess imported supplies in wet years and in meeting drought demands. Semitropic Water Bank is currently Valley Water's only out-of-county groundwater banking program. The recently adopted Water Supply Master Plan 2050 reflects the need to maintain banking storage capacities, and the diversification of groundwater banking program will reduce risks inherent to any singular program. Additionally, diversification may provide additional put and take capacities to optimize Valley Water's existing imported water supplies. Since the April 2025 update to the Water Supply and Demand Management Committee, staff continued to coordinate with various entities across California that are managing existing or developing new banking programs. This update highlights the latest on Semitropic Water Bank, Willow Springs Water Bank, and Irvine Ranch Water Bank.
Semitropic Water Bank
Valley Water entered into a groundwater banking agreement with Semitropic Water Storage District (Semitropic) in 1997. The agreement provides Valley Water with 350,000 AF of total storage capacity, a minimum of 31,675 acre-feet (AF) of annual recharge capacity, and a minimum of 31,500 AF of annual recovery capacity. The current agreement with Semitropic expires in 2035.
1,2,3-Trichloropropane (TCP) was detected in certain recovery wells in Semitropic, which can impact Semitropic's ability to recover stored water to the California Aqueduct in a future pro...
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