HR: 1340h
AN: H53B-1240    [Abstracts]
TI: A Field Investigation to Assess the Effects of Riparian Vegetation Management on Alluvial Channel Morphology
AU: * Kinzel, P J
EM: pjkinzel@usgs.gov
AF: U.S. Geological Survey, Box 25046 DFC MS 413, Lakewood, CO 80225 United States
AU: Nelson, J M
EM: jmn@usgs.gov
AF: U.S. Geological Survey, Box 25046 DFC MS 413, Lakewood, CO 80225 United States
AB: The Platte River in central Nebraska intersects a principal migratory route for North American waterfowl including several endangered and threatened avian species. Upstream water resource development has altered the regime of water and sediment inputs to the central Platte River. The once wide, braided channel has narrowed significantly over the last century and a dense riparian forest has been established along some reaches. A recovery program proposed for the Platte River will use adaptive management to restore habitats lost through vegetation encroachment and channel narrowing. The Cottonwood Ranch, a 2,650-acre parcel of land owned by Nebraska Public Power District (NPPD), is a recovery program property that is being enhanced for avian habitat. Vegetation has been removed from river banks and islands to promote lateral erosion and widening of the channel with the objective of increasing unobstructed views for cranes. Because riparian management activities also have the potential to cause geomorphic change downstream, the U.S. Geological Survey designed a monitoring study to detect what effects, if any, the management might have upon the local channel morphology and sediment-transport processes. The study required the measurement of cross-section elevation profiles and bed-material size gradations upstream, within, and downstream of the managed area prior to, and following, the management activities. However, since the monitoring study began in 2000, Platte River flows have been relatively low. Hence, up to this point, fluvial action has not stimulated substantial lateral erosion and downstream redistribution of sediments from the managed area. The monitoring protocol, while specifically developed to study the effects of vegetation clearing, could be applied to evaluate the geomorphic response of additional reaches of the Platte River to other proposed management activities, including sediment augmentation from island leveling and controlled releases from upstream dams.
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting