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Monitoring Well Installation Report - Chevron Station #9-5775, Lodi, CA April 7, 2000 One groundwater monitoring well (MW -5), four vapor extraction wells (VE -I through VE -4), and two soil borings (SB -2 and S13-3) were installed on the subject site on December 20 through 22, 1999 One groundwater monitoring well (MW -6) and one groundwater extraction well (EX -1) were installed on-site, and one groundwater monitoring well (MW -7) was installed west of the subject site on February 15 and 16, 2000 Two groundwater monitoring wells (MW -8 and MW -9) were installed south and southwest of the subject site on February 28, 2000 Wells MW -6 through MW -9 were drilled to a depth of 65 feet below ground surface (bgs), well MW -5 was drilled to a depth of 75 feet bgs, and soil borings SB -2 and SB -3 were drilled to a depth of 55 feet bgs using a truck -mounted drill rig equipped with 8 -inch -diameter hollow -stem augers Well EX -1 was drilled to a depth of 65 feet bgs, wells VE -1, VE -3, and VE -4 were drilled to a depth of 55 feet bgs, and well VE -2 was drilled to a depth of 35 feet bgs using a truck- mounted drill rig equipped with 10 -inch -diameter hollow -stem augers A GR geologist observed the drilling activities For all wells and soil borings except well MW -6, soil samples were collected at five- foot intervals for description and preparation of a log, and for possible chemical analysis Boring logs are included in Appendix C Well MW -6 was installed less than 5 feet from MW -5, and was not sampled or logged Well construction details for well MW -6 are included in Appendix B Locations of newly installed wells are shown on Figure 2 Copies of the Well Driller's Reports are included in Appendix B Soil cuttings generated during drilling activities were placed on and covered with plastic Composite disposal confirmation samples SP -(A -D), SPA (A -D), SP -2 (A -D), and SP -3 (A -D) were collected from the stockpiled soil cuttings Stockpile sampling procedures are presented in Appendix A The stockpiled soil cuttings are still at the site pending removal by Integrated Wastestream Management (IWM) . Well Installation Groundwater monitoring wells MW -5 through MW -9 were constructed using 2-mch diameter Schedule 40 polyvinyl chloride (PVC) casing and screen material, and groundwater extraction well EX -1 and vapor extraction wells VE -1 through VE -4 were constructed using 4 -inch diameter Schedule 40 PVC casing and screen material Wells MW -6 through MW -9 are screened from 45 to 65 feet bgs, well MW -5 is screened from 70 to 75 feet bgs, well EX -1 is screened from 53 to 65 feet bgs, and vapor extractions well VE -1 though VE -4 are screened from 40 to 55, 20 to 35, 25 to 35, and 40 to 55 feet bgs, respectively The annular space around the screens in each well is packed with Lonestar #3 graded sand The sandpack is followed by a seal of bentonite chips hydrated with clean water, then neat cement to approximately 1 -foot bgs The top of each well is protected by a vault box, locking well cap and lock The vault box is installed flush with the ground surface, and is set in concrete Well construction details are included with the boring logs in Appendix C Well Monitoring, Development and_Samplin Newly installed well MW -5 was developed and sampled on January 4, 2000 Well MW -5 was redeveloped and a shallow sample was collected from the top of the water column using a disposable bailer on March 1, 2000 A deep sample was collected from the screened interval at 73 feet below top of casing (btoc) with a bomb sampler on March 2, 2000 Wells MW -6, MW -8, and MW -9 were developed and sampled on March 1, 2000, and well MW -7 was developed and sampled on March 2, 2000 Depth - to -water was measured in all groundwater monitoring and extraction wells on March 1, 2000, and a groundwater potentiometric map was generated from this data (Figure 4) Each well was checked for the presence of separate phase hydrocarbons (SPHs) No SPHs were observed in the wells None of the 61 newly installed wells dewatered during development Following development, groundwater samples 34640806-1