PROJ01828 - Laserfiche WebLink

Home Browse Search

i ~ Ms. Honey R. Moschetti, President -2- December 19, 1994 SITE INSPECTION On October 13, 1994, GEl made a site visit to DeWeese Dam. We were accompanied for a portion of our visit by Mr. Henry Moschetti and Mr. Joe Brunetto of the DeWeese-Dye Ditch and Reservoir Company. During our visit, we visually inspected the dam and appurtenances, including: the crest and upper concrete portion of the dam; the upstream and downstream faces of the dam; the downstream abutment and foundation contacts; the service spillway in the right dam abutment; and the outlet of the outlet works pipes. Measurements were taken of the upper concrete portion (approximately the top 12 feet) of the dam for later use in developing the cross section geometry for analysis. The reservoir water level was estimated to be about 8 feet below the "ledge" at the bottom of the upper concrete section; or at about gage height 22. At this elevation the water surface is about 20 feet below the crest of the dam. Releases were being made from the reservoir through one of the two upper outlet conduits. No estimate was made of the rate of outlet discharge. PRESENT CONDITION OF DAM DeWeese Dam is a concrete-masonry curved gravity structure located on Grape Creek in Custer County, Colorado. The dam is about five miles north of the town of Westc1iff. DeWeese Dam impounds DeWeese Reservoir, which stores irrigation water for Company shareholders. The reservoir also provides recreational and in-stream flow maintenance benefits. Little information is available regarding the design or construction of the original structure or subsequent raises and improvements. Based on available information, it appears that the original dam was constructed in 1903, and comprises a concrete section with a masonry downstream facing. Sometime between 1903 and 1931, a four-foot high concrete raise was constructed on the crest of the original structure. A second concrete raise was constructed in about 1931, extending about eight feet above the first raise. Design/construction drawings for the second raise indicate that it was reinforced with 5/8-inch diameter steel bars. No information is available regarding reinforcement in the original dam or first concrete raise. The present dam has a structural height of about 63 feet, and a total crest length of about 425 feet. The maximum normal pool elevation is at the spillway crest, about 1.7 feet below the dam crest. The reservoir volume at the maximum normal pool is about 4,020 acre-feet. An uncontrolled spillway is located in the right abutment. The spillway is an open cut through rock, with a width of about 60 feet and a reported capacity at the dam crest of about 390 cubic feet per second (cfs). The outlet works consists of three pipes through the dam near the central maximum section of the dam. Two 16-inch diameter outlet pipes are located about 42 feet below the crest of the dam; a third, 36-inch diameter pipe is located below the 16-inch pipes, about 50 feet below the dam crest. The outlet conduits are controlled by slide gates located on the upstream face of the dam. 943 II\DDREPORT.L l1l