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I I I I I I I I I I I I I I I I I I I CHAPTER V: PLAN OF DEYElOPMENT 1.0 SITE INSPECTIONS 1.1 General Peterson lake Dam and Reservoir were inspected on several occasions during the study, by various members of the MKE staff. The first visit was a site reconnaissance inspection performed on July 11, 19S6. At that time, a Phase I Inspecti on Check1 i st was fi lled out, simil ar to the inspection form used by the State Engineer's Office. During the visit, the reservoir was completely drained, except for the permanent dead pool at elevation 9478.5; even though the reservoir is only restricted to gage height (G.H.) 20.0, which is equal to elevation 9498. This report is included in Appendix A. The dam was inspected again during the bore hole and test pit phase of the geotechnical investigation between August 12 and August 18, 1986, at which time the outlet works was a1 so inspected. The 1 ast vi si t to the si te was made on September 23, 1986, to collect additional soil samples. The reservoir remained empty throughout the summer. 1.2 Dam 1.2.1 Description Peterson lake Dam is an earth embankment with a crest elevation of 9517, with a maximum height of 57 feet and a crest length of approximately 175 feet. The dam was originally built in the early 1920's of clay, sand, and gravel, deri ved from gl aci a1 deposi ts and organi c materi a1 from withi n the reservoi r. The dam is located in a "Y" shaped valley incised into Precambrian bedrock and appears to be founded on sound gnei ss and mi ca schi st. Re1 eases from the reservoir are controlled by an outlet works that discharges into an unnamed tributary of the Cache 1a Poudre River. A concrete service spillway pipe is embedded in the 1 eft groi n wi th a control el evati on of 9510. An auxfl fary spi 11 way is located in a saddl e at the northeast corner of the -36-