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screened with aphoto-ionization detector (PID) for organic vapors. To prevent cross- contamination, drill angers and sample tubes were steam-cleaned prior to initial use at the site and behveen boreholes. Boreholes BH-10 and BH-16 were advanced to the southeast of the AST system. BH-I 1 was installed to the north of the AST system. BH-12 and BH-13 were installed downgradient of the AST system to the northeast. BH-14 was installed to the east of the AST system. Borehole BH-15 was advanced for the purpose of installing an upgradient groundwater monitoring well to the west of the vehicle maintenance shop, and to the southwest of the AST system. During drilling, the field geologist logged the soils encountered using the Unified Soil Classification System (L1SCS) in accordance with ASTM D 2488-34, depth to groundwater, field indicators of contamination (i.e. PID readings, staining, and odors), sample depth interval and identification, and other pertinent observations. Attached as Appendix A aze logs presenting information recorded during advancement of the boreholes. In genera], sandy soils with clay, gravel, and cobbles were encountered. Saturated soils were encountered at depths Icss than 2 feet below ground surface in all of the boreholes advanced. A soil sample collected from Bii-]0 at a depth interval of 1 to 3 feet exhibited elevated organic vapor concentration of 135 ppm. Orgvcic vapor concentrations for all other soil sample intervals collected from the boreholes ringed from 0.8 to 12.E ppm. Typically, the soil sample interval about the satwated zone exhibiting the highest organic vapor measurement in each borehole is collected for laboratory analysis. Because the groundwater was encountered within 2 feet of the ground surface in each of the boreholes advanced, the uppermost sample interval from each borehole was submitted for laboratory analysis. Because the location of borehole Bk I-1 S was selected for the purpose of installing act upgradient groundwater monitoring well, a soil sample from was not submitted from BF[-15 for laboratory analysis. 1.1 Monitorin, !Ve!!s Immediately following installation, boreholes BH-10 through BH-1~ were converted to temporary groundwater monitor wells MW-10 through MW-15. A "Notice of Intent to Construct Ivionitoring Holes" form vas completed for the six wells and submitted to the Office of the State Engineer on May 6, 1996. A copy of the completed notice is attached as Appendix B. Monitoring well MW-10 was advanced to the southeast of the AST system. IvfW-11 was 'utstalled to the north of the AST system. IvfW-12 and MW-13 were installed downgradient of the AST system to the northeast. IviW-14 was installed to the east of the AST system. IvfW-15 vas installed as an upgradient well to the west of the vehicle maintenance shop, and to the southwest of the AST system. ERNt-ROCKY M1tOUNrA1N, M(:. P:\I000\S WPC\961019V2EPORT.DOC Printed on Recycled Paper 4