Laserfiche WebLink
27 October 2000 <br /> AGE-NC Project No. 98-0497 <br /> Page 6 of 8 <br /> 3.8. SURVEYING <br /> The casing elevation of each well installed for the National Freight investigation was surveyed <br /> relative to City of Stockton Bench Mark #179 . On 03 October 2000, a California state-licensed <br /> survey engineer from Baumbach&Piazza, Inc. surveyed a reference point on the top of each ground <br /> water monitoring well casing at the site to the nearest 0.01-foot relative to the City of Stockton <br /> Bench Marks and Description at 25.86 feet above mean sea level(msl). The results of the monitoring <br /> well survey are contained in Table 1. The surveying report (Baumbach & Piazza) is presented in <br /> Appendix E. <br /> 4.0. FINDINGS <br /> Ground water elevations were determined by subtracting the measured depths-to-water from the <br /> surveyed casing elevations. Ground water flow directions were determined by contouring the water <br /> elevations on a scaled site plan (Figure 2). <br /> 4. 1. STRATIGRAPHY <br /> During the installation of the monitoring well soil pilot borings, tan to brown, dry silt or silty sand <br /> and sand was encountered at 5 to 55 feet bsg. Silty clay or clayey silt was encountered between 55 <br /> and 70 feet bsg and again between 75 and 80 feet bsg with a silty sand layer encountered between <br /> 70 and 75 feet bsg. Between 80 feet bsg and total depth(100 feet bsg) of P-3,poorly graded sand and <br /> gravel were encountered. Ground water was present at approximately 63 feet bsg during <br /> advancement of the four soil borings. Petroleum hydrocarbon odor was noted in the samples <br /> collected from P-3 and MW-1. PID data, where available, is included on the boring logs (Appendix <br /> A). <br /> 4.2. ANALYTICAL RESULTS FROM SOIL SAMPLES <br /> A total of 21 soil samples were analyzed for TPH-g, TPH-d, BTEX, seven fuel additives, EDB and <br /> 1,2-DCA by EPA Method 8260 Modified. <br /> _ • TPH-g was not detected above laboratory reporting Iimits in any of the soil samples collected <br /> and analyzed. BTEX compounds were detected in samples P3-75 and MW1-75 at <br /> concentrations of 0.018 milligrams per kilogram (mg/kg) and 0.025 mg/kg, respectively <br /> (xylenes). TPH-d was detected in soil samples P3-100 and MW1-75 at concentrations of 7.8 <br /> Advanced Geo Envirunmental,Inc. <br />