SS3.21 Deconstructing Rivers: The Ecological, Geomorphic, and Social Consequences of Dam Removal
Date: Thursday, June 13, 2002
Time: 10:00:00 AM
Location: Colwood
 
CantelliA, University of Genova, Genova, Italy, ale@diam.unige.it
Paola, C, , University of Minnesota, Minnesota, USA, cpaola@tc.umn.edu
Parker, G, , University of Minnesota, Minneapolis, USA, parke002@tc.umn.edu
 
EXPERIMENTAL STUDY ON THE EVOLUTION OF THE EROSIVE FRONT INDUCED BY REMOVAL OF A DAM
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There are many reasons to remove a dam: many of these structures are approaching their design life and therefore may be unsafe; reservoirs behind dams are filling with sediment and reduce the dam's ability to store water and produce electricity losing their effectiveness; the dam induce environmental damage (i.e., fish habitat); river returned to their natural state may have a positive economic benefit. The paper reports on a laboratory investigation on the evolution of the erosive front induced by dam removal. We built a laboratory model of a dam, and observed the sedimentation of the reservoir due to the propagation of the delta front and the erosion of the delta front during the dam removal. The evolution time and the topography of the front were observed. Analysis of local erosion and its effect on bank width was performed; two principal erosive trend were detected: at the beginning of the erosion process for each section the width decreases until it reaches minimum value; only later is observed banks erosion.