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256 J. R. SHUMAN <br />Table III. Physical and chemical issues related to the presence of dams or dam removal, and past or proposed dam <br />removals reviewed in this paper where that issue was discussed or is expected to be important <br />Issue Applicable dam removal <br />Release of toxic sediments during and following dam removal Fort Edward Dam <br />Sediment transport to downstream areas during and following dam removal Fort Edward Dam <br /> Newaygo Dam <br /> Woolen Mills Dam <br /> Sailing Dam <br /> Elwha and Glines Canyon dams <br />Changes to river channel morphology above and/or below the dam before Newaygo Dam <br />and after dam removal Woolen Mills Dam <br /> Elwha and Glines Canyon dams <br />Degraded water quality during the drawdown for dam removal Fort Edward Dam <br /> Elwha and Glines Canyon dams <br />Recontouring of floodplain to assure floodplain function after dam removal Woolen Mills Dam <br /> Elwha and Glines Canyon dams <br />Revegetation to prevent soil erosion following the drawdown for dam removal Woolen Mills Dam <br /> Sailing Dam <br /> Elwha and Glines Canyon dams <br />Trapping of sediments in impoundment All dams, but to varying degrees <br />flooding patterns following dam removal (i.e. connectivity between river and floodplain), the potential for <br />degradation of water quality during the drawdown for dam removal and revegetation of exposed floodplain <br />soils to prevent soil erosion following drawdown for dam removal (Table III). These issues all require <br />assessments to determine their significance to a particular dam and river. <br />Biological and ecological issues are typically more obvious to the public when a dam removal is proposed <br />(Table IV). The most common impact of dams is the blockage of fish movements up the impounded <br />river (Welcomme, 1979; Rulifson et al., 1982; Stevens et al., 1987; Mills, 1989; Healey, 1991). The <br />area impounded by the dam frequently constitutes a loss of habitat for certain species of fish (Hynes, <br />1970), depending on dam placement along the longitudinal gradient (Ward and Stanford, 1989). Water <br />Table IV. Biological and ecological issues relevant to the retention or removal of dams which have been voiced over the <br />Rodman Dam removal controversy <br />Issue Relative significance <br />Blockage of upstream movement by fish and other <br />animals by the dam <br />Loss of fish habitat by impoundment <br />Loss of floodplain forest wetlands due to impoundment <br />Impacts to threatened and endangered species <br />Changes in bird communities utilizing the <br />river/impoundment <br />Fragmented wildlife corridors due to presence of <br />impoundment rather than river <br />Changes in wildlife species utilization due to impoundment <br />Movement of sediments by the river to downstream <br />habitats during flood events reduced by impoundment <br />Changes in discharge volume and flow downstream <br />from the dam <br />All dams; some far more significant than others <br />All dams, but only for certain species <br />Wetland losses from all dams, but to varying degrees <br />Some dams (e.g. Glen Canyon Dam in Colorado and <br />Utah); Elwha and Glines Canyon dams <br />Probably all dams; but not discussed in published work <br />Important to varying degrees <br />Probably all dams, but to varying degrees <br />Probably all dams; depends on dam structure and <br />operation <br />Probably all dams, but to varying degrees