ARCHIVED REPORTS XR0012675 - Laserfiche WebLink

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�a J. H. KLEINFELDER&ASSOCIATES File: 24-1045-2/271704 `�- --•� `1� ,�c . r December 1, 1986 Page 2 A1,11 laboratory laboratory for quantified chemical analysis. After proper developmenlikSa water sample will be collected from the monitoring well and delivered to a State approved laboratory for chemical analysis. A report presenting information obtained from field and laboratory activities would be prepared. Soil BoriagslSoil-SamRling We recommend the placement of one initial soil boring B-1 at the proposed location shown on Plate 1. Should volatile hydrocarbons be detected by field screening in the initial boring, four additional borings B-2 through B-5 would be drilled at locations shown on Plate 1. The borings would be drilled by a truck-mounted drilling rig with hollow stem auger. To minimize the possibility of cross contamination, all auger and associated drilling equipment would be steam cleaned prior to the drilling of each boring. The soil sampler and brass liners would be cleaned in a trisodium phosphate bath followed by a tap water bath and final distilled water rinse before the collection of each sample. Soil samples would be collected at five foot intervals from each . boring, starting at the surface and terminating 10 feet above anticipated standing ground water. Soil samples would be collected by advancing the boring to a point immediately above the sampling depth and then driving a Modified California Sampler into the soil.. Samples will be screened in the field for volatile hydrocarbons with a portable field photoionization detector (PID) and then sealed with aluminum foil and plastic caps. The samples would be immediately stored in an iced cooler under chain-of-custody. Upon completion of drilling and sampling, the boring would be backfilled with a cement-bentonite alurry to minimize the possibility of creating a conduit for contaminant transport from the surface to groundwater. Wall -Construction If the initial boring contains petroleum hydrocarbons, a monitoring well would be completed in one of the soil borings. According to our estimates, ground water should be encountered approximately 40 to 60 feet below the ground surface. The monitoring well would be completed to a depth of 15 feet below the ground water table or five feet into'the first saturated clay layer encountered. The wells will be constructed of two-inch flush threaded PVC pipe, perforated with 20 feet of 0.020 inch machine—slotted--screen. -I f—the—aquifer_-is--found-to be--in aconfined-- condition, confined condition, the well screen would begin at the depth where water was first encountered. If it is unconfined, the well screen would extend 5 feet above ..the water table. The termination of the well will be a maximum of 15 feet below the water table or into the first competent clay layer below