ARCHIVED REPORTS_XR0008963 - Laserfiche WebLink

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Lammersville School District March 3, 1992 02320 2124 Page 3 3 4 MONITORING WELL INSTALLATION, DEVELOPMENT, AND SURVEYING After completing each boring, groundwater monitoring wells were installed The wells were constructed using 2-inch-diameter, 0 020-inch-slot, PVC well screen, and blank casing A filter pack consisting of #3 Monterey Sand was placed in the annular space of the well from the bottom of the boring up to one foot above the screened interval A one-foot-thick layer of 1/2-inch bentonite pellets was set above the filter pack in order to seal the well The remaining annulus was then sealed with a neat cement slurry The wellhead was protected with a watertight traffic-rated road box The road box was elevated slightly to facilitate drainage of surface waters away from the well A locking cap sealed the wellhead Well completion details are presented in Appendix A On January 29,1992, the new groundwater monitoring wells were developed to remove fines and enhance hydraulic communication between the wells and surrounding aquifer Approximately 8 to 10 well volumes were removed from each well During development, pH, temperature, and conductivity readings were recorded All water generated during development and sampling was stored on site in Department of Transportation IDOT) approved drums pending proper disposal Fallowing development, the new wells were surveyed relative Y to existing wells in order to establish vertical control 4 0 GROUNDWATER MONITORING AND SAMPLING in response to a request by Ms Margaret Lagono of SJCEHD, data collected by McCain Environmental Services (McCain) on May 20 and August 27, 1991 have been included in this report The methods used to collect these samples have not been communicated to Groundwater Technology The data collected by McCain in 1991 and by Groundwater Technology in 1992 were used to prepare maps of the potentiometnc surface (Figures 3, 4, and 5), dissolved TPH-G (Figures 6, 8, and 10), and dissolved benzene (Figures 7, 9, and 11) Monitoring data are summarized in Tables 1, 2, and 3 On January 14, 1992, groundwater monitoring wells MW-2, MW-5, MW-6, MW-7, and MW-8 were gauged to determine depth to water (DTW) and to check for the presence of liquid-phase hydrocarbons The wells were then purged of four well volumes and allowed to recover to at least 80 percent of the static water level Samples collected were decanted into 40-milliliter glass vials and . delivered to a State of California certified laboratory along with a chain-of-custody manifest The samples were analyzed for the presence of BTEX and TPH-G using EPA Methods 5030/8020/8015 21 240SRl RPT - IF-1 ";-� GROUNDWATER TECHNOLOGY