Laserfiche WebLink
- Report-Soel and Groundwater Irrvestigation <br /> -' Gateway Project,City of Stockton <br /> April 10,2000 <br /> n Page-3- <br /> 4;. <br /> water. Geoprobe borings GPI, GP2, GP3, GP4, and GP5=were terminated at depths of approximately.30, <br /> 30,28, 32 and 24 feet bgs, respectively..;Groundwater was encountered at approximately 25, 15, 24,_and <br /> 1T feet bgs .in Geoprobe}borings _GP 1, GP2, GP4, and GP5, respectively. Groundwater was not <br /> encountered in GP3. Upon completion'of the drilling and sampling, the boreholes were filled with a <br /> bentonite/grout mixture. The upper three feet of GP2 was filled with cement grout with lamp black dye <br /> to blend in the asphaltic concrete surface. <br /> 3.3 SOW SAWLING <br /> 3.3A Sampling Procedures <br /> Soil samples were collected from each Geoprobe boring based on field observations;and were generally <br /> collected at•four-foot intervals-beginning at approximately 12 feet below ground surface(bgs). Four soil <br /> samples were selected for,laboratory analyses from each of the five Geoprobe borings (20 total)based on <br /> field observations, `including photo-ionization detector (PID) measurements and/or the presence of <br /> 4 <br /> petroleum hydrocarbon staining and/or .,odor. . Some soil samples were collected below the depth that <br /> groundwater was encountered for limited-verticalcharacterization at the.request of Ms. Lori Duncan, the ._ <br /> on-'site SJCPHS/EHD representative. - <br /> zU <br /> According to the work plan dated March.10,'2000, the Geoprobe borings would be continually logged <br /> using the Geoprobe macro-core method (1.75-inch diameter,-4-foot long, core barrel,'fitted with a clean, <br /> one-time use, polyethylene liner). The very stiff, clayey soil encountered in Geoprobe borings.GPI and <br /> GP2, however, indicated that the macro-core method would probably not penetrate the subsurface tothe <br /> anticipated depth to groundwater (approximately 30 feet bgs). Therefoz-e, beginning at approximately at <br /> 16 and 5 feet bgs in GP 1 and GP2, respectively; a smaller-diameter (one-inch) coring tool that collected <br /> discreet, two-foot long sample cores was. advanced. Because groundwater was encountered in GP2 at. <br /> approximately 15 feet bgs (approximatelyF 15 feet less-than the anticipated depth), the larger macro-core <br /> method was attempted,in.GP3 through°GP5. With,the exception of GP4, the macro-core method was <br /> successful in advancing to sufficient depth to obtain a�oundwater sample. <br /> - <br /> tJ CONDOM <br />