HR: 14:30h
AN: NB23F-05 INVITED     [Abstracts]
TI: How Riparian Vegetation Influences Stream Morphology and Process: Implications for Restoration
AU: * Pizzuto, J E
EM: pizzuto@udel.edu
AF: Jim Pizzuto, Dept. of Geology University of Delaware, Newark, DE 19716 United States
AB: Vegetation is often used to enhance bank stabilization efforts and as part of more generalized restoration designs, but the influence of vegetation on geomorphic processes is poorly understood. Recent research suggests that changes in riparian vegetation can influence channel morphology, rates of erosion and deposition, and by extension, the entire sediment budget of a reach. In recent studies in the Mid-Atlantic region, reaches with forested riparian vegetation were compared to immediately adjacent non-forested (grassy) riparian vegetation to explain why channels with forested vegetation are wider than their non-forested counterparts. At study sites, erosion occurs at cutbanks in curving reaches, while deposition is localized on active floodplains at the insides of bends. In narrow, non-forested reaches, rates of bank erosion and channel migration are high, while in wide, forested reaches, rates of bank erosion and channel migration are low. These results may be explained using the ratio of two dimensionless parameters, alpha and E. Alpha represents the influence of vegetation on rates of active floodplain deposition (it is very high in non-forested reaches, and very low in forested reaches), while E is proportional to rates of cutbank migration (it is high in non-forested areas and low in forested areas). The width is proportional to E/alpha. These results could lead to improved assessment of the geomorphic effects of restoration designs that involve changes in riparian vegetation.
DE: 0400 Biogeosciences
DE: 1803 Anthropogenic effects
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly