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<br />WOOdward-clylJ <br /> <br />.\ <br /> <br />4.0 <br />SCOPE OF WORK <br /> <br />4.1 PROPOSED SCOPE OF WORK <br /> <br />Based on our understanding of the history of Brush Hollow Dam, and our experience <br />with over 100 "old dams", we have developed a detailed scope of work to complete the <br />investigation of the apparent slope movement and development of repair <br />recommendations, The purpose of the field investigations will be to identify the <br />potential failure mode and slide surface within the embankment/foundation, Stability <br />analyses will be performed using the results of the field investigations and laboratory test <br />results on samples obtained in the field. We will then develop recommendations for <br />embankment repairs based on the results of the investigations and analyses and our <br />extensive experience on similar projects. We recommend the following detailed scope <br />of work: <br /> <br />Task 1 - Test Holes/Piezometers <br /> <br />Our field investigations will consist of drilling test holes and installing piezometers and <br />movement monuments in the dam. We will locate the drill holes as described below, <br />based on a review of the records for Brush Hollow Dam and our field reconnaissance. <br />We recommend drilling a minimum of 5 test holes. One additional drill hole could be <br />added depending on conditions encountered at the five drill hole locations described <br />below. Two holes will be drilled from the dam crest at the area of the cracking, The <br />crest drill holes will be used to attempt to locate the slide plane within the dam and to <br />obtain samples of the embankment material for laboratory testing. Two drill holes will <br />be drilled from the upstream slope at the same stations as the crest drill holes. The <br />purpose of the upstream drill holes will be to sample the upstream zone of the <br />embankment and to try to locate the potential slide plane. One drill hole will be located <br />at the downstream toe to provide further definition of the embankment and foundation <br />section and to investigate the potential for a slide plane within the downstream slope, <br />Surface signs and the occurrence of drawdown prior to identification of cracking may <br />indicate upstream slope movement; however, the absence of movement in the crest may <br />Woodward-Clyde Consultants <br /> <br />23360/PR0.4 12-08-93(8:53am)/RPT <br /> <br />4-1 <br />