ARCHIVED REPORTS XR0000298 - Laserfiche WebLink

Home Browse Search

' FIELD REPORT QUARTERLY GROUNDWATER MONITORING SAN JOAQUIN COUNTY MOSQUITO ABATEMENT DISTRICT LODI FACILITY, LODI, CALIFORNIA On November 2, 1992, ROY F. WESTON, INC (WESTON) conducted groundwater sampling at the San Joaquin County Mosquito Abatement District (SJCMAD) facility at 200 North Beckman Road, Lodi, California This field work had been performed to meet the requirements of the San Joaquin County Public Health Services, Environmental Health Division (EHD) letters dated June 7, 1991 and February 10, 1992 Upon arrival at the site, the standing water levels and total well depths were measured in all monitor wells using an electronic well sounding device Refer to Figure A-1 for approximate monitor well locations MW-1, MW-2 and MW-3 were dry The elevation of groundwater relative to Mean Sea Level (MSL) in MW-4 was calculated and the results are presented in Table A-1 TABLE A-1 Water Level EIevations November 2, 1992 Well Location Well Elevation Depth to Water Water Elevation (feet, MSL)' (feet) (feet, MSL)' MW-1 54 11 Dry Dry MW-2 5428 Dry Dry MW-3 5403 Dry Dry MW-4 5443 5966 -523 1 MSL = relative to Mean Sea Level The water level measurement and total well depth were used to calculate the required purge ' volume for the well A clean submersible pump was used to purge MW-4 and as the well was pumped, the discharge rate was measured in order to calculate the time required to obtain three casing volumes MW-4 was purged dry and allowed to recover six times Ultimately over three ' casing volumes (25 gallons) were removed and the well was allowed to fully recover prior to sampling At the beginning, during, and end of the purge process, the purge water pH, electrical conductivity, and temperature were measured This information was recorded on field water sampling data sheets and final values are presented in Table A-2 MXCUUTS SfCMAD-4 WP A-1 11!30/42