ARCHIVED REPORTS XR0001523 - Laserfiche WebLink

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well screen In each well, the screen interval was placed from 30 to 50 feet bgs Blank PVC casing was threaded into the top of the well screen and extended to the surface In each well, a filter pack of#3 graded and washed silica sand was placed through the hollow stem augers as they were slowly retrieved and until the sand pack reached approximately two feet above the top of the screened interval Following the placement of the sand packs, the driller developed each of the wells by the surge and purge method Each of the wells was surged for approximately ten minutes using a wire-line surge block system Between surging cycles, approximately ten gallons of groundwater were bailed from each well Following well development, a three-foot seal of hydrated bentonite chips was placed within the annular space r between the borehole and the well casing A surface seal of 20 1 cement bentonite grout was placed over the hydrated bentonite The tops of the wells were secured with water-tight locking caps and 8-incl, diameter, traffic-rated utility boxes The monitoring well logs are included in Appendix C On January 11, 1999, Morrow Surveying (California Licensed Land Surveyor#5161) surveyed each of the newly installed wellheads Morrow Surveying located each of the wells and measured the elevation of the top of each well casing to the nearest 0 01 foot The elevations were referenced to the city of Stockton Benchmark#183, a brass disc in a monument box at the intersection of the west side of Airport Way and the centerline of Charter Way (Elevation 17 132 feet) The surveyor's report is included as Appendix D 2 2 3 Groundwater_Monitoring, Sampling and Analysis On January 11, 1999, groundwater from the newly-installed wells was monitored and sampled Upon arrival at the site, each of the wellheads was inspected, unlocked and opened Depth-to- groundwater was measured in each of the wells using a water level indicator capable of measuring groundwater to within 0 01 foot Following the groundwater level measurements, each of the wells was purged and sampled The wells were purged using a bailer until at least three well casing volumes were extracted and/or after groundwater temperature, pH and electrical conductivity values had stabilized Following _ well purging, groundwater was sampled from the wells using dedicated disposable bailers and laboratory-supplied containers Each sample was labeled, packaged in an iced cooler and transported under chain-of-custody documentation to Kiff Kiff analyzed each of the groundwater samples for TPH-as-gasoline, BTEX, MTBE, DIPE, ETBE, TAME and TBA by EPA Method 8260B . 8