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and pumped using the positive displacement method in the presence of EHD inspector. 3.01 WELL INSTALLATION A. Well installation shall be in the presence of EHD inspectors. Contractor shall follow the guidelines for well inspection as specified herein. B. The Contractor shall measure the total depth of the borehole using a weighted sounding line or other method as agreed with the Engineer and EHD inspector. If heaving or cave-ins have taken place, then the Contractor shall clean out or re-drill the borehole before well installation. C. The Contractor shall ask for inspection by the Engineer of the casing, screen, and any other well construction materials prior to installation. D. The blank casing, 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. The monitoring well casing shall be fitted with a two-foot long sump below the well screen interval. 4. Casing centralizers shall be affixed to the well casing during assembly. A centralizer shall be placed above and below the well screen of the 2-inch casing. A centralizer shall be placed above the well screen of the 1-inch casing. Additional centralizers shall be placed at 40-foot spacing to maintain 2-inch separation between the borehole wall, monitoring well casing, and sounding pipe within the annular space. 5. Contractor shall connect and lower the well casing assembly gently. 6. 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. 7. 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. 8. Contractor shall place the gravel envelope into the annular space around the screened interval through a tremie pipe. The tremie pipe shall be installed within North County G-15&G-16 San Joaquin County Groundwater Monitoring Well Specifications 7 Public Works Dept Solid Waste Division