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y Workplan for Aquifer Pumping Test, Well Installation&Well Destruction Southwest Hide Company,Manteca,CA Project No.W0508.00 Page 3 Task 3 - Installation of Three Groundwater Monitoring Wells One groundwater well will be installed as a replacement well for existing Well 1. The well will be located outside the proposed cap. Two temporary wells will be installed to serve as monitoring points for the aquifer pumping test. They will be located within 50 feet of the proposed extraction well. Three borings will be advanced using 10-inch O.D. hollow stem augers. The approximate total depths of the replacement well and of the temporary wells are 38 feet and 20 feet, respectively. Drilling will be conducted by a State-licensed (C57) drilling company. A field geologist will be present to log all drill cuttings and soil samples. Descriptions of soil types encountered, sample collection intervals, and well construction details will be recorded on boring/well logs and included in the summary report. Soil samples will be collected at five foot intervals from the replacement well boring. One soil sample collected from each boring will be sent using chain-of-custody record to a State- certified laboratory for analysis of TDS, sodium, and chloride. The borings will be completed as groundwater monitoring wells. Monitoring wells will be constructed of PVC well screen and casing. The replacement well will be 4-inches in diameter and the temporary wells will be 2- inches in diameter. A 0.010-inch well screen slot and #2/12 mesh sandpack will be used. Neat cement will be used to seal the wells in accordance with California Well Standards (December 1981). To protect the integrity of the wells, a locking, water-tight well plug will be installed on the wells. Typical well details are shown on Figure 3. Task 4 - Well Surveying and Development Following installation of the wells the top of the wellheads will be surveyed and tied into the existing wells. Measurement of depth to water in wells will be completed. For development of the wells a minimum of three well volumes (casing and sandpack) will be purged. Temperature, pH, water elevation, and electrical conductivity will be measured and allowed to stabilize. The replacement well will be sampled during the next quarterly monitoring event. Task 5 - Conduct an Aquifer Pumping Test RESNA will conduct a 24-hour aquifer pumping test to determine groundwater characteristics beneath the site. Well 8 will be used as the extraction well for the test. A series of short term step-drawdown tests will be performed to determine the sustainable pumping rate form Well 8. The primary pumping test will consist of extracting groundwater from Well 8 for up to 12 hours WP-0893.FNL