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D. The well screens, bentonite seals and neat cement seals shall be installed in accordance with the following sequence: 1. Contractor shall estimate the length of casings needed and verify with the Engineer before lowering into the boring. Well casing shall be at least 5 feet above grade. 2. Contractor shall not use couplings, or glue to join well casings. 3. Contractor shall install a PVC slip end cap or a well plug on the top of both well casings before placing the casing in the bore hole. 4. Contractor shall connect and lower the well casing assembly gently. 5. If the well casing assembly is dropped, lowered abruptly, or for any other reason suspected of being damaged during placement, the well casing assembly shall be removed from the borehole for inspection by the Engineer. The need to inspect the casing will be at the sole judgment of the Engineer. 6. If the well casing rises after being placed in the borehole, the Contractor shall not place any drilling equipment such as drill pipe, hammers, etc. on the casing to prevent the casing from rising. Contractor shall notify the Engineer immediately of rising casing, and shall measure the amount of rise. 7. Contractor shall place the sand pack into the annular space around the screened interval. Clean water and a tremie pipe may be used to assist with sand pack placement. If the well assembly is installed through the hollow stem augers, the augers shall be pulled slowly during sand pack installation. 8. Contractor shall minimize bridging of the sand by pouring the sand in the bore hole gently and not in large quantity. Patience shall be exercised by the Contractor. 9. Contractor shall monitor the sand pack settlement by measuring the sand level with a weighted tape. Contractor shall also monitor the top of the well casing to detect any movement due to settlement or from drive casing removal. 10.Contractor shall periodically gently surge the water inside the well casing and screen to compress the sand pack while placing the sand. Contractor shall measure the top of the sand pack periodically 11. Contractor shall add sand shall until the sand pack is above the top of the screened interval as shown on the well construction details. 12. Once the placement of the sand packed interval is completed, the contractor shall measure and record the depth to the top of the pack in the presence of the Engineer. 13.Contractor shall install bentonite seal in the annular space above the sand pack. Add bentonite gradually to avoid bridging. Contractor shall measure the depth of the bentonite plug using a weighted tape. FH -Groundwater Monitoring Well Specifications 8/15/18 Page 6 of 12 San Joaquin County Public Works Dept Solid Waste Division