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a m - - ,.• _- Report-Sail and Groundwater Investigation Gateway Project,City of Siock[fon4. _ April 10,2600 a- Page-6- . r the soil samples._. Petroleum-hydro6arboin odors were.not.noted for the field-observation soil samples collected from GN`at approximately 19.5, 23:5, 27.5 and 3 I:S feet bgs: Native soil-appeared to'beiencountered In GP5 at approximately 4 feet.bgs.s Clay and sandy clay were generally encountered down to the total depth of the boring k approximately 24 feet bgs.- Similar to GPI through GP4, field:,observations generally indicated thatstiff clay was encountered°in GPS between approximately II and 12 feet bgs. Generally soft, damp-to wet sandy.and/or silty clay was encountered from approximately. 12 to-24 feet bgs in GP5: PID measurement of 7.1, 4:2, 3.0, and 5.0 ppm total H -. organic vapors were recorded for the field observation soil samples collected from GP5:at approximately 11.5, 15.5,--l.9.5 and 23.5 feet bgs. It should be noted that PID readings that are just above the instrument detection limit of 1 ppm total organic vapors may not be representative of actual petioleum hydrocarbon r. concentrations in the soil samples. Petroleum hydrocarbon odors were not noted for the field observation soil samples collected from GP5 at approximately 19.5, 23.5, 27.5 and 31.5 feet bgs. 3.4 GEOPROBE ,GROUNDWATER SAMPLING , _ Groundwater was encounter � ed during the'field work at approximately 25,u 15, 24, and'l 7,feet bgs in GPI b GP2, GP4,--and GP5;`respectively. Grounifwater,was not.encountered in GP3. The generally very fine- grained soil encountered in the Geoprobe borings prevented determination-of the static groundwater level in the borings- In each of borings GP 1, GP2; GP4, and GP5, it appearsthat the depth ithat groundwater was encountered at,was representative of seepage into the boring in sandier zones, and was not representative of long term, static water table conditions. While moisture was present-in the relatively sandy horizon encountered in GP3 (between-12 and 24 feet bgs), not enough groundwater was present to fill the boring with dmeasurable quantity of groundwater A groundwater sample was collected from GP 1, GP2, GP4, and GP5 using the Geoprobe sampler. The sampler utilized a sealed, _water-tight, 1 stainless steel sample chamber- and PVC screen. When groundwater was encountered, the sampler was deployed:- The sample chamber-was opened by pulling _ back on the body of the sampler', exposing the screen...When the screen was full, agroundwater.sample was retrieved by manually pumping (raising and.lowering) the sample chamber with'a clean, single-use. length of polyethylene tubing containing a.'Neck valve at the submerged end. W -s_. CONDOR