WORK PLANS - Laserfiche WebLink

Home Browse Search

j I Ia of the borehole, leaving a slotted interval above the occurrence of groundwater to observe for floating product. 'Th6 sand pack will be placed to"a point about two feet above the slots. 'A bentonite seal will be placed atop the.sand pack, and a cement grout seal placed atop the bentonite using a tremie line, filling from the bottom to top of the borehole.„A traffic.rated ',well head access box'and'se'cunty device'will`complete the wellhead. �` S Monitoring Well Sampling and Development The monitoring well will be developed to 'iemove the drilling muck, grade the sand pack and provide a more complete hydraulic connection to the aquifer. A well development log will be kept of the well volumes 'removed until the water becomes clear and the amount.of sand pumped is-minimal. `The. well will be allowed to recover.for at least 72 hours prior to sampling. The well casing will .," be surveyed to a known datum to accurately measure groundwater elevation contours. Well.Casin2LElevation Survey t Ila The monitoring well casing elevation. will be.surveyed to a known elevation datum so I . -,accurate groundwater elevations and flow gradient can be-measured. J .Wright will use the same elevation datum, if.available, as those identified!in the file review wells at the aforementioned sites. Should a common datum not be available, Wright will survey the selected wells (pending access permission)-to a known,sea-level referenced 'datum for groundwater level measurements. Groundwater Sampling The monitoring well will be purged using calculated well volumes based upon the depth to water.in the casing.. Depth to groundwater measurements will be.made to the nearest one- one hundredth of one foot; and also,checkedfor the presence.of`separate phase'lproduct. ,The well,will be purged to remove stagnant}Fwater in}the well casing a,As each purge ,volume is removed,:measurements of pH; electrical conductivity and temperature will be taken until these parameters stabilize over two purge.volume removals, which is interpreted to be aquifer water entering the casing., The well will be allowed to recover-to;about 80% of the initially measured water level, after.,which,the sample will.tie"collected,' ` The water sample will be 'carefully,collected with a clean bailer and. poured into the appropriate laboratory prepared container with minimum cavitation. The water sample will be labeled, logged onto a chain-of-custody form, and placed in a chilled ice chest. Upon .completion of well sampling, the well will be closed and locked. RFChemical Analysis One (1) capillary fringe soil sample, and one(1) groundwater samples will be analyzed at a State certified analytical laboratoryfrom- the exploratory boring. These samples will be chemically analyzed for the following; Total Petroleum Hydrocarbons as Gasoline (TPHG), Benzene (B), Toluene (T), Ethylbenzene (E) and Xylene (X), Methyl-tert-butyl- ether(MTBE) and fuel oxygenates, 1;2 Dichloroethane and Ethylene Dibromide using EPA Methods 3510/8015, 8020, 8240 and 8260. The analyses will be performed on an "normal" turnaround (about five working days). Report A Monitoring Well Installation and Monitoring Report will be prepared for submittal to the y City of Tracy, which would then be forwarded to the PHS EHD and the adjacent property owner of Tracy Auto Stereo. The report will include the field methods, permits, Page 3