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<br />North Creede <br />A culvert was placed in East Willow Creek to allow building in a small flat area on the south <br />side of the creek. The culvert is undersized, and an abrupt bend in the culvert collects timber <br />debris. Reportedly, the culvert periodically plugs and is often overtopped during annual high <br />flows causing damage to the surrounding roadway. Unplugging the culvert and repairing road <br />damage is a regular maintenance problem. A large flow could potentially flood and damage the <br />surrounding cabins and residences. In addition, the timber retaining walls upstream and <br />downstream from the culvert are deteriorating and may soon cause additional failures. <br /> <br />Commodore Mine <br />A huge amount of waste rock was removed from the Commodore and Nelson Level tunnels and <br />now fills a large portion of the steep canyon on West Willow Creek. The miners installed <br />relatively makeshift hydraulic structures to convey West Willow Creek over these tailings. <br />Currently, a wooden flume carries water over an upper tailings pile. The water drops from this <br />flume to a pipe that carries the water through the lower tailings pile to a large drop. The wooden <br />flume has deteriorated and may soon need to be replaced. Sections of the steel pipe near the <br />drop are reported to have large gaps that may not be stable during a large flood. Some water <br />may be infiltrating into the tailings piles at numerous points in the system leading to increased <br />pollution in West Willow Creek. Finally, the system is susceptible to plugging by debris and <br />may be undersized to handle a large flood. Flooding could potentially wash tons of mine tailings <br />into West Willow Creek that could even be carried to the Rio Grande. Erosion of the tailings <br />piles could also wash mine timbers and cribbings into the stream that could cause additional <br />flooding and damage downstream. <br /> <br />Amethyst Mine <br />The stream channel above the Amethyst Mine tunnel is quite steep and intersects a slide of mine <br />related waste rock and timber debris. Further upstream is a heavily wooded area that contributes <br />natural timber debris to the channel. A culvert with a "grizzly" grating conveys West Willow <br />Creek under the access to the Amethyst Mine tunnel. The basin above the culvert has filled with <br />sediment, and large amounts of timber debris collect on the grizzly during high flows. Removal <br />of the timber debris is almost an annual maintenance task, and high flood flows could quickly <br />plug the grizzly with debris and cause flood damage to the mine tunnel access and nearby mine <br />waste piles. <br /> <br />1.4.2 Sediment and Debris <br />The watershed of Upper Willow Creek contains a large amount of mobile sediments and debris. <br />Mine tailing piles and other areas disturbed by historic mining activities have left a large source <br />of debris and sediment available for transport by Willow Creek. The very steep slopes of the <br />watershed, which in some places is geologically unstable, also provides an abundant natural <br />supply of debris and sediments. The steep gradient of the streambed creates erosive conditions <br />and enables rapid transport of this material downstream. <br /> <br />Sediment deposition within the channel may decrease channel capacity, may increase lateral <br />migration and bank erosion, and may affect the habitat, recreational, and aesthetic values of the <br />stream. Deposited sediment requires periodic and sometimes vigilant removal in some areas to <br />ensure adequate flood capacity. An oversupply of sediment tends to impact natural bank and <br /> <br />1-7 <br />