ARCHIVED REPORTS XR0000207 - Laserfiche WebLink

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' Califorrua Department of Transportation July 7, 1994 Project No 102818-01 A minimum of three casing volumes were purged from each of the monitoring wells prior to collection of water saZmple Temperature, pH, and specific conductance measurements were made in e the purpose of establishing when a representative groundwater sample could t e g ued in each well until pH, temperature, and 1 conductivity did not vary by re th 10 percent The monutoring well purge water was placed in labelled 55-gallon, DOT-approved drums and left on site in the stewardship of Caltrans Field measurements and general observations for each well were recorded on the well sampling records presented in Appendix A After purging, the water in each well was allowed to recover to at least 80 percent of its original elevation Water samples were then collected using a disposable, Teflon, bottom- discharging bailer, transferred to an appropriate sample container, labelled, and placed in a t cooler contairung ice The samples were transported to Quality Assurance Laboratories for chemical testing under chain-of-custody protocol s GROUNDWATER MONITORING WELL ABANDONhIENT As part of our field activities, nine groundwater monitonng wells were abandoned at the facility The monitoring wells were abandoned because they are either currently dry or are located witlun the footprint of proposed new buildings The required monitoring well 9 abandonment permit was obtained from the San Joaquin County Public Health Services Environmental Health Division (PHSEHD) prior to commencement of abandonment and is presented as Appendix S Groundwater monitoring wells MWA, MW-2, MW-3, MW--4, MW-5, MW-6, MW-7,and MW-8 were abandoned by drilling out the well (including the well casing, well screen, filter pack and annular seal) The excavations resulting from the removal ' of monitoring wells MW-1 through MW-5 were filled to round surface with a mixture of mora g g g neat cement and approximately 5 percent bentonite grout Monitoring wells MW-6, MW-7, and MW-8 were initiallckfilled with bentonite chips to approximately 5 feet above the groundwater level a", yd ted with potable water The excavations were subsequently filled to groundxture of neat cement and approximately 5 percent bentonite grout 3Yl�Ofll�®&�®®L1'�