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-7- <br />A new outlet works and main dam were constructed downstream from the original location. <br />The new embankment has a 25 -foot wide crest with upstream slope of 2.8:1 and downstream <br />slope of 2.5:1. A chimney filter was placed to control the internal phreatic surface and an <br />earth filled cutoff was constructed 5 feet into bedrock. The upstream face of the main dam <br />is protected by riprap consisting of broken concrete. The outlet works consist of two 4.5 foot <br />wide and 5 foot high rectangular shaped concrete conduits-cut into bedrock. This work, which <br />was begun in 1992, was completed in 1995. <br />2.7 Spillway and Flood Freeboard <br />The spillway on the reservoir is located north of the Main Dam. The spillway consists of an <br />unlined earth channel with a minimum crest elevation bf 3709'.5, which is approximately 2.5 <br />feet above the normal water level. The spillway crest is the gravel- surfaced county road. The <br />spillway cross section is a trough- shaped cross section 1,600 feet wide and 5.5 feet deep. <br />Currently, a flood storage and wave freeboard height of 5.5 feet is provided above the spillway <br />level, which provides approximately ,8,900 acre feet of uncontrolled flood surcharge storage. <br />Additional surcharge storage of 3,700 acre feet is available between the normal water level <br />and the spillway crest (2.5 feet); Table I provides a listing of the reservoir storage capacity <br />versus water storage level. <br />3.0 HYDROLOGIC-'AND GEOTECHNICAL CONCERNS <br />3.1 Hydrologic Concerns <br />3.1.1 Wave Runup andWave' Freeboard Requirements <br />Generally, the Julesburg °-Reservoir dams are currently provided with 8.0 feet of flood surcharge <br />freeboard, and Dam No's. 2 and 3 are also provided with an additional 3.0 -foot high parapet <br />wall for wave runup protection. Using techniques for determining wave height, wave setup <br />and wave runup on the dam facing materials presented in Embankment Dams Upstream Slope <br />Protection, prepared by the International Committee on Large Dams (ICOLD), it was concluded <br />that the current freeboard allowance of 8.0 feet is acceptable for wave considerations. A <br />Zreports \97 -1 -500. nk <br />