Hydrologic Landscape Characterization for the Pacific Northwest,USA |
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| Authors: | Scott G Leibowitz Randy L Comeleo Parker J Wigington Jr Marc H Weber Eric A Sproles Keith A Sawicz |
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| Affiliation: | 1. National Health and Environmental Effects Research Laboratory, Western Ecology Division, U.S. Environmental Protection Agency, Corvallis, Oregon;2. Center for Advanced Studies in Arid Zones, University of La Serena, La Serena, Chile;3. Oak Ridge Institute for Science and Education, c/o USEPA National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, Oregon |
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| Abstract: | We update the Wigington et al. (2013) hydrologic landscape (HL) approach to make it more broadly applicable and apply the revised approach to the Pacific Northwest (PNW; i.e., Oregon, Washington, and Idaho). Specific changes incorporated are the use of assessment units based on National Hydrography Dataset Plus V2 catchments, a modified snowmelt model validated over a broader area, an aquifer permeability index that does not require preexisting aquifer permeability maps, and aquifer and soil permeability classes based on uniform criteria. Comparison of Oregon results for the revised and original approaches found fewer and larger assessment units, loss of summer seasonality, and changes in rankings and proportions of aquifer and soil permeability classes. Differences could be explained by three factors: an increased assessment unit size, a reduced number of permeability classes, and use of smaller cutoff values for the permeability classes. The distributions of the revised HLs in five groups of Oregon rivers were similar to the original HLs but less variable. The improvements reported here should allow the revised HL approach to be applied more often in situations requiring hydrologic classification and allow greater confidence in results. We also apply the map results to the development of hydrologic landscape regions. |
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| Keywords: | hydrologic classification hydrologic cycle watersheds rivers/streams runoff geospatial analysis National Hydrography Dataset NHD Pacific Northwest |
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