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i 2-10 2.2.2 Piezometer Installation - December 1982 To evaluate the condition of the central portion of the dam, seventeen piezometers were installed at eight locations along the dam crest. Figures 1 and 4 show the locations of the piezometers designated as Piezometer P-21 through P-28. The piezometers were also designed as monitoring points for observation of future dam performance. Five of the piezometer completions were made in nests at two or three depths and are indicated as subscript 'A', 'B', or 'C' to the piezometer location number. Figure 4 shows the nested piezometer designations. The other two piezometers (P-26 and P-27) were single completions. The holes for the piezometers were drilled using hollow stem augers without any drilling fluid to prevent any possibility of hydraulic fracturing in the dam fill material. Each completion for a given piezometer was made in a separate boring offset about five feet (in plan) from the other completions for that piezometer. The deepest completion at each piezometer location was drilled first and logged. Appendix A contain the logs for the deepest boring at each site. Piezometer installation details for each completion are given in Appendix B. The water levels measured in the piezometers are shown in Figure 4 and in Sections B -B' and C -C' in Figure 5. The sections indicate water levels similar to pond elevation near the upstream edge of the dam crest. Downstream of this point the water level elevation are signifi- cantly below the pond elevation. Rising head permeability tests were conducted in the piezometers to determine the coefficient of permeability of the dam fill material. Only piezometers measuring a water level are capable of providing a permeability value through rising head tests. The coefficient of perme- ability calculated from the rising head tests is given in Table 2.