Site modelling methods for detecting hydrologic alteration of flood frequency and flood duration in the floodplain below the carlyle dam,lower Kaskaskia River,Illinois, USA |
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Authors: | Susan P. Romano Sara G. Baer James J. Zaczek Karl W. J. Williard |
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Affiliation: | 1. Department of Biological Sciences, Institute for Environmental Studies, Western Illinois University, Quad Cities 3561 60th Street Moline, IL 61265, USA;2. Department of Plant Biology, Center for Ecology, Southern Illinois University‐Carbondale, Carbondale, IL 62901, USA;3. Department of Forestry, Southern Illinois University‐Carbondale, Carbondale, IL 62901‐4411, USA |
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Abstract: | Reports concerning the influence of dams on river hydrology vary among researchers, interest groups and government agencies. These often contradicting statements may occur because changes in hydrology caused by dams are distinct for each dam and river watershed. The objective of this research was to use site specific techniques to determine if the 1967 installation of the Carlyle Dam, lower Kaskaskia River, Illinois, altered flood frequency and duration within the forested floodplain located below the dam. Results indicated a decrease in flood duration and frequency, and a decrease in annual flood frequency variation at a site 6.4 km below the dam. Pre‐dam versus post‐dam differences in flood frequency and duration at the site 32.2 km below the dam were related to climate rather than dam effects. Although dam impacts are a concern, this research shows that distance downstream from the dam and downstream tributary and watershed characteristics should be considered before assuming that the dam has changed hydrologic parameters for portions of rivers. This research also indicates that areas of the lower Kaskaskia River may still maintain hydrologic ecological integrity, and could be targeted for restoration and adaptive management purposes. Hydrologic modelling combined with river gage and on‐site well measurement techniques presented in this study could provide detailed flood frequency and duration information for land use, sociological and geomorphological questions in focus areas within river floodplains. Copyright © 2008 John Wiley & Sons, Ltd. |
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Keywords: | river hydrology floodplain frequency duration flooding modelling dam |
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