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Flood effects on an Alaskan stream restoration project: the value of long-term monitoring

Journal of the American Water Resources Association

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Abstract

On a nationwide basis, few stream restoration projects have long-term programs in place to monitor the effects of floods on channel and floodplain configuration and floodplain vegetation, but long-term and event-based monitoring is required to measure the effects of these stochastic events and to use the knowledge for adaptive management and the design of future projects. This paper describes a long-term monitoring effort (15 years) on a stream restoration project in Glen Creek in Denali National Park and Preserve in Alaska. The stream channel and floodplain of Glen Creek had been severely degraded over a period of 80 years by placer mining for gold, which left many reaches with unstable and incised streambeds without functioning vegetated floodplains. The objectives of the original project, initiated in 1991, were to develop and test methods for the hydraulic design of channel and floodplain morphology and for floodplain stabilization and riparian habitat recovery, and to conduct research and monitoring to provide information for future projects in similar degraded watersheds. Monitoring methods included surveyed stream cross-sections, vegetation plots, and aerial, ground, and satellite photos. In this paper we address the immediate and outlying effects of a 25-year flood on the stream and floodplain geometry and riparian vegetation. The long-term monitoring revealed that significant channel widening occurred following the flood, likely caused by excessive upstream sediment loading and the fairly slow development of floodplain vegetation in this climate. Our results illustrated design flaws, particularly in regard to identification and analysis of sediment sources and the dominant processes of channel adjustment.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Flood effects on an Alaskan stream restoration project: the value of long-term monitoring
Series title:
Journal of the American Water Resources Association
Volume
45
Issue:
6
Year Published:
2009
Language:
English
Publisher:
Wiley
Publisher location:
Hoboken, NJ
Contributing office(s):
Alaska Science Center Biology WTEB
Description:
10 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of the American Water Resources Association
First page:
1424
Last page:
1433
Country:
United States
State:
Alaska
Other Geospatial:
Denali National Park And Preserve