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City of Redwood City Proposal No. 03--187 <br />September 18, 2003 Page No. 6 <br /> <br /> PURPOSE AND SCOPE OF SERVICES <br /> <br />The purpose of our services would be to evaluate thepresent stability of the old slide area and the <br />likelihood that it could expand uphill, involving Nob Hill Rd and the adjacent residences. This <br />evaluation would be based on a site investigation as described above. The engineering analyses of <br />the collected data would develop conclusions, opinions, and recommendations regarding: <br /> <br />· stability of the existing (2003) slide and slope area <br />· the general nature of any remedial work necessary <br />· the apparent efficiency of existing subsurface drainage system and appropriate measures to <br /> improve and/or maintain the system <br />· additional measures and/or investigations that should be performed, if any, prior to <br /> development of the lots <br /> <br />Specifically, we propose the scope of our services consist of the following tasks. <br /> <br />1. Research and review pertinent geotechnical and geological maps and reports relevant to the <br /> site area regarding local soil conditions, and the geologic and seismic history of the site and <br /> vicinity. <br /> <br />2. Obtain a permit from the San Mateo County Environmental Health Services Division for <br /> drilling soil borings, installing 2 new piezometers and improving 2 existing piezometers. <br /> <br />3. Mark the locations of the new borings at the site and notify Underground Service Alert <br /> (USA) at least 72 hours in advance of the drilling to locate utilities within the street and <br /> boring areas. <br /> <br />4. Re-develop the exiting piezometers at Borings 4 and 5 (as shown on the Subdrainage Plan) <br /> by surging the water in the casing with a surge block, and then attempting to pump 20 casing <br /> volumes of water from each well. The water will be placed in drams, and moved to the <br /> subject vacant lots. <br /> <br />5. Drill a total of three exploratory borings. One boring would be drilled on the west side of <br /> Nob Hill Rd, and a second boring would be drilled just above the old scarp area with hollow <br /> stem drilling equipment. A third boring would be drilled within the old slide mass, near the <br /> rear of the two lots with portable drilling equipment. The drilling operations will be directed <br /> by one of our field engineers, who would also maintain a log of the materials encountered, <br /> and collect soil samples for visual examination and laboratory testing. When completed, a <br /> lockable piezometer will be installed in the two lower borings (not the one in the street) in <br /> accordance with requirements of the San Mateo County Environmental Health Services <br /> Division. <br /> <br /> 6. Perform laboratory testing of selected samples of the soil/bedrock materials as required to <br /> <br /> <br />