CLEAN-UP AND RESTORATION OF GLEN CREEK, DENALI NATIONAL PARK AND PRESERVE, ALASKA

Upper Glen Creek, in Denali National Park and Preserve, is a severely disturbed stream (from gold placer mining) with extensive abandoned mining equipment and supplies, hazardous substance containers, and numerous known hydrocarbon spills. The stream disturbances include unstable or excessively confined streambeds, as well as oversteep floodplains along many reaches of the entire stream length. Piles of mine tailings have replaced much of the native streambed. Riparian vegetation is absent along large portions of most channel bank and flooplain reaches. Floodplain soils, necessary for vegetative recovery, are absent altogether. Soils replenishment, normally a function of annual flooding, is impossible due to confined streambeds or braided, unstable channels.

An earthwork restoration plan was developed in 2003 to reduce several tailings piles, rebuild the floodplain in one reach of the stream valley, and reconstruct a meandering stream course. In 2004, an NPS crew redistributed and recountoured 4.5 acres of tailings and floodplain, and re-established over 1500 feet of stream channel, re-enforced meander corners with 12 rock vanes and 2 coconut coir log installations and transplanted over 100 willow and alder plants to improve channel and floodplain stability. Additionally, the crew inventoried 26 abandoned equipment or supply sites, and hauled 15 tons (two 30-yard dumpsters) of scrap steel & trash for disposal.

An assessment of the reconstruction efforts in the summer of 2005 revealed no constructed stream channel cutting or abandonment, and only minor bank erosion in short sections at the toe of the primary tailings pile. Furthermore, there was a 90% survival rate of the willow/alder plants in the project area. Although a one-year evaluation of project success is perhaps premature, these results lend well to an optimistic future of an enhanced natural recovery for Glen Creek, and other similar impaired stream valleys in Denali National Park.