Laserfiche WebLink
RECENT FIELD WORK <br /> 1 <br /> Between July 29th and August 3rd, 1993 we drilled two additional <br /> wells at this site and one boring. The wells were drilled to <br /> a depth of 65 feet and 2 inch Schedule 40 PVC slotted (0 .02) <br /> casing was placed from the well bottom upward 20 feet. The <br /> remaining casing was 2" blank schedule 40 PVC and was placed <br /> to the surface. Number 3 sand was placed opposite the slotted <br /> section and about 20 feet above the last slot. Then the <br /> r annulus was filled with hydrated bentonite for 3 feet and the <br /> remainder of the annulus was sealed with neat cement. A <br /> traffic box was placed over the well and cemented to the <br /> pavement. (See Well Logs. ) <br /> The wells were developed by removing approximately 70 gallons of <br /> water at which time the sediment was greatly reduced. <br /> Approximately 24 to 48 hours later, the wells were surveyed, <br /> with a spirit level, to tie the tops of the casings to the local <br /> datum, measured for depth to water, and sampled. ( See <br /> Protocols) <br /> i <br /> SITE CHARACTERIZATION <br /> GEOLOGY <br /> The site and all nearby terrain are underlain by non-marine, <br />• fine-grained sediments which are tentatively assigned to the <br /> Modesto Formation of Pleistocene age. (USGS Bulletin 1470 <br /> Marchand and Alwordt, 1981) . Although the Modesto is typically <br /> composed of coarser-grained material such as sands and gravels <br />• it is reasonable, on the basis of stratigraphic position, to <br /> consider these finer-grained sediments to be the distal portion <br /> of the large alluvial fans which make up the Modesto. <br /> The materials penetrated in our borings are chiefly clay, silty <br />• <br /> clay and clayey silt. Sandy strata, although present, are <br /> Page 4 <br />• <br />