Authors: Mary Lewan*, Eastern Washington University, Samantha Stark, Eastern Washington University, Erin D Dascher, Eastern Washington University
Topics: Water Resources and Hydrology, Land Use and Land Cover Change
Keywords: River Connectivity, Barrier Assessment Tool, Fragmentation, Land Use/Cover, Spokane River Basin
Session Type: Guided Poster
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River connectivity is important for maintaining healthy ecosystems. Dams, culverts, and road crossings are anthropogenic batteries that fragment rivers and alter their sediment and flow regimes. Changes to land cover/use can also be a source of river fragmentation. Natural stream channels can be buried by impervious surfaces, segmented and displaced by storm water drainage systems, and/or otherwise altered by the processes of urbanization. This research investigates the impacts of urbanization on steam connectivity in four sub-watersheds of the Spokane River Basin. Instream barriers were identified from existing datasets including StreamNet and Spokane County Open Source Data, and through the examination of aerial imagery. The NHDPlus High Resolution geodatabase represented the dendritic stream network within the study area, and land use/cover data was obtained from the USDA Geospatial Data Gateway. The Barrier Assessment Tool (BAT) modeled river connectivity and provided data on the extent and number of functional river networks (FRNs). FRNs were then classified by length and land use/cover. Preliminary results indicate that highly urbanized areas have fewer and smaller FRNs compared to other land use/cover types. The examination of how urbanization increases river fragmentation can provide helpful insight and inform management practices aimed at maintaining and restoring connectivity.