1978-05-01_HYDROLOGY - M1977493 - Laserfiche WebLink

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7. Flood Control Dam and Interceptors Climax, which recycles its water, keeps fresh water runoff from enter- ing the mill water system by a series of canals that intercept the run- off. These interceptor canals divert water around the tailing area and discharge it downstream of the tailing ponds. The interceptors were sized based on hydrological studies of the different drainage areas. The interceptor system, when combined with the available surge capacity of the water pool area (after the first 10-years of operation) and the de- cant line capacity, will allow the Mayflower Tailing Pond to pass a prob- able maximum flood without damage to the tailing dam. A large drainage, Clinton Gulch, is tributary to the tailing pond. It was not feasible to construct an interceptor large enough to handle the potential floods from this gulch, and it was therefore decided to con- struct a flood control dam. Design work began in 1972 on the Clinton Dam portion of the Mayflower Tailing Pond. The dam was designed primarily for flood protection for the Mayflower tailing facilities. Construction began in 1974 and is now complete. The dam was constructed across Clinton Creek about three miles north of Fremont Pass. It has a crest which is 64 feet wide and 1500 feet long. The total height of the dam is 170 feet at a crest elevation of 11,072 feet and contains over 1. 7 million cubic yards of material. The maxi- mum flood stage capacity of the reservoir is 5,350 acre-feet and the normal area of the reservoir is 95 acres. The crest of the dam is used as a portion of Colorado Highway 91, which is under relocation. A bench was built near the crest on the downstream slope to carry the 42-inch concrete tailing line, Mountain Bell telephone line and Western Slope Gas pipeline. Near the toe of the dam a bench was built to carry No. 1 Canal, which brings water from Humbug, Mayflower and Clinton Creeks into the system. Two parking lots have been built to allow fishermen and hikers access to the reservoir. It was stocked with 2,000 native cutthroat trout in 1976 and an additional 500 cutthroat trout were placed in it in 1977. All areas disturbed by construction have been reseeded and should be revegetated by the time traffic is allowed on the new highway in 1978. Due to the steepness of the terrain, cut slope stability problems were encountered during construction of the canals, particularly during the spring runoff periods. Rock gabions have been installed to provide relief for these problem areas. Gabions were also installed as flood spillway structures and were used to create small still water pools in creek relocations.