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Hydrologic and mass-movement hazards near McCarthy Wrangell-St Elias National Park and Preserve, Alaska

Water-Resources Investigations Report 93-4078

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Abstract

At the confluence of McCarthy Creek and the Kennicott River, about 1 mile from the terminus of Kennicott Glacier, Alaska, McCarthy Creek and Kennicott River basins are prone to several natural hazards including floods; formation and failure of natural dams; stream erosion and sediment deposi- tion; snow avalanches; aufeis; and the mass wasting of rock, soil, and debris. Low-lying areas along the Kennicott River flood annually, commonly during late July or early August, as a result of outbursts from glacier-dammed lakes, but these floods can occur during any month of the year. Flood plains along McCarthy Creek and its tributaries are frequently flooded and prone to rapid erosion and deposition during intense rainfall and periods of rapid snow- melt. Sediments from continual mass wasting accumu- late in stream channels and are mobilized during floods. Several lateral erosion, scour, and deposition resulting from floods in September 1980 and August 1985 destroyed bridges and several historic structures at McCarthy were jeopardized by the rapidly eroding northern streambank of McCarthy Creek. Flood discharges were determined indirectly using the slope-area method at two high-gradient reaches on the Kennicott River, four on McCarthy Creek, and one on Nikolai Creek. During the flood of September 13, 1980, peak discharge for McCarthy Creek at McCarthy was 4,500 cubic feet per second.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Hydrologic and mass-movement hazards near McCarthy Wrangell-St Elias National Park and Preserve, Alaska
Series title:
Water-Resources Investigations Report
Series number:
93-4078
Edition:
-
Year Published:
1993
Language:
ENGLISH
Publisher:
U.S. Geological Survey ; Earth Science Information Center, Open-File Reports Section [distributor],
Description:
vi, 55 p. :ill., maps ;28 cm.