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Ruvalcaba, Cesar [EHD] From: Casey Kipf <ckipf@condorearth.com> Sent: Wednesday, August 3, 2022 4:04 PM To: Shih, Steven [EHD] Cc: Ruvalcaba, Cesar [EHD] Subject: RE: San Joaquin County Well Permit Application - 22700 Gawne Road CAUTION: This email is originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe. Hi Steven, Sorry for the delay. The evaluation indicates that the proposed well is located in an area with relatively low domestic well density and is not likely to interfere significantly with existing off-site wells, create unreasonable groundwater level declines/reductions in aquifer storage or to create issues with infrastructure due to subsidence and it can be approved pending any other issues that you might have with the application. Summary: - The Applicant indicates that the two proposed AG wells 22700 and 23004 Gawne Rd will be separated approximately 800 feet to minimize well interference between the two. - The closest known off-site wells are located approximately 2,400 (east) and 2,500 feet south of the proposed well. - Groundwater levels estimated by DWR well data are seasonally between 120 to 145 feet below ground surface. Seasonally, water levels fluctuate approximately 10 to 15 feet between high and low water levels in this area; lowest water levels measured were recorded during the early 1990's, approximately 20 to 30 feet lower than current groundwater conditions. - The permit application proposes a minimum well casing/grout seal of 50 feet therefore it will span the intermediate and deep zones of the aquifer with water -bearing zones anticipated to be primarily unconfined, but potentially under both unconfined and confined conditions. - The annual total extracted volume is estimated to be approximately 78 million gallons, a peak pumping rate of 1,200 GPM, and an annualized pumping rate of approximately 260 GPM. - The estimated aquifer volume below the 80 -acre parcel contains approximately 9,200 acre-feet of water storage. The proposed extraction volume of 240 acre-feet per year is approximately 2.6% of the seasonal aquifer storage beneath the parcel aquifer without regard to recharge each season and is therefore considered sustainable. - The proposed well site is not located within the extents of the Corcoran Clay, subsurface water -bearing sediments are semi -consolidated to consolidated, historic water levels have been significantly lower in the past, and the well is not located in an area where subsidence is currently indicated, therefore subsidence is unlikely to be significance or to create issues. Aquifer Model results: - Maximum drawdown at the proposed Ag pumping well is estimated to be up to 40 feet at peak pumping rates and a radius of influence (unconfined conditions) and estimated to be approximately 850 feet for short term/intermittent pumping. - The predicted drawdown at the nearest off-site well (2,400 feet from the proposed well) during sustained pumping for various time intervals is listed below. The conservative case (confined aquifer model) predicts 5 to 6 feet of drawdown 2,400 feet from the pumping well as a result of long-term, sustained pumping at the