Rattlesnake Creek - "Research Project 1985 Final Report" - Montana, USA

Book excerpt: Normal 0 Rattlesnake Creek is a small wadeable creek which runs through the Rattlesnake Wilderness and Recreation Area for approximately 23 miles and flows into the Clarkfork River in downtown Missoula, Montana. Until 1983, Rattlesnake Creek was used as Missoula's municipal water supply. In 1940 the creek was closed to fishing above the water supply reservoir, which is located 2.5 miles upstream from the mouth. Due to an outbreak of Giardia in 1983, Missoula began using wells as its sole source of water thus allowing recreational use of the water for the first time in 45 years. In the winter of 1984-85 the Montana Fish and Game Commission opened Rattlesnake Creek to catch and release fishing above Beeskove Creek. A six-mile hike limits access to the catch and release fishing section. No vehicle travel is allowed but mountain bikers for easier access can use an old fire road. The current study on Rattlesnake Creek was designed to obtain more intensive data than otherwise possible by state or federal agencies. This report summarizes the results of research initiated in the spring of 1985 to evaluate the population dynamics of the unfished cutthroat fishery below Beeskove Creek and to evaluate the effects of special regulations in the area above Beeskove Creek. The Study Area The upper Rattlesnake Creek drainage is located 5.6 miles (8.3 km) north of Missoula in western Montana (Figure 1). The drainage encompasses approximately 81.3 square miles (21,053 ha), most of which is owned by the United States Forest Service. Rattlesnake Creek originates on the flanks of McLeod and Triangle peaks, flowing south-southwest to its confluence with the Clark Fork of the Columbia River at Missoula (Figure 1). In 23.3 miles (37.0 km), from source to mouth, the creek descends 5291.0 ft. (1613 m) for a mean gradient of 4.3%. Of the nine perennial tributaries, three (Wrangle, Lake, and High Falls creeks) originate from glacial lakes; the remaining 6 (Porcupine, East Fork of Rattlesnake, Beeskove, Pilcher, Fraser and Spring creeks) originate from springs. Numerous intermittent streams also feed Rattlesnake Creek. More than 40 lakes are located in the upper drainage mostly on the west side. Geologic studies indicate that the parent materials include argillites, quartzites, and limestone of the Precambrian Belt series as well as Cambrian shales and limestones (Nelson & Dobell,1961). The watershed is characterized by relatively high peak discharge per unit area, a disproportionately large amount from the upper elevations (Van der Poel, 1979). Rattlesnake Creek is a 3rd order stream, which flows through a fairly steep valley. The valley bottom is an open pine-larch forest; cottonwoods and shrubs line the creek. Occasionally the valley bottom opens up into small, grassy meadows. Higher in the drainage the valley is increasingly timbered and steep. A stable natural character generally persists throughout the drainage. The substrate of Rattlesnake Creek is mostly gravel and cobble with a few boulders. The average flow is approximately 45-50 cubic feet per second. Although the creek does not currently supply Missoula with water, it is primarily managed as a watershed and secondarily managed as a recreational area (USFS Management Plan, 1984). The possibility of building a small filtration plant on the creek and again using the water for Missoula's municipal water supply is being discussed. A small water company dam already exists 2.5-miles upstream from the mouth of Rattlesnake Creek. The area would be the most probable site for a filtration plant. The water company dam prevents all upstream fish migration from the Clarkfork River.