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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Disturbance Ecology II
THE EFFECTS OF ANTHROPOGENIC ALTERATIONS ON SURFACE CONNECTIVITY WITHIN AN ALLUVIAL FLOODPLAIN IN THE YAKIMA RIVER BASIN, WASHINGTON.
D.J. Eitemiller, M.L. Uebelacker, C.P. Arango, and K.L. Clark. Department of Geography and Land Studies 7420, Central Washington University, Ellensburg, Washington, 98926
Human impacts to riverine ecosystems have severed the physical connectivity of the river to the riverine environment. During the past 120 years, an extensive and complex assemblage of anthropogenic features has been integrated into the disturbance regime template of all floodplains directly associated with the Yakima River. Dams and storage reservoirs regulate and supplement in-stream flow for irrigated agriculture. Railroad and highway beds, which often act as levees, dissect the riverine landscape. Wetlands and riparian forests are cleared for utilization by agriculture, industry, recreation and rural development, and a system of dikes that protect and maintain these land use activities has emerged. To assist in identifying how these cultural features alter the structure and function of riverine ecosystems an in-depth study focused on mapping their emergence across seven alluvial floodplains within the Yakima basin was recently undertaken. A final analysis shows a 68 percent reduction in riverine habitat once inundated by small, frequent, flood events within just one of these floodplains. The real contribution of the study is the creation of an ecological baseline that will help managers implement changes directed at preserving and promoting riverine ecosystem health.
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