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Slowing the flow: Setting priorities and defining success in Lake Superior’s South Shore watersheds
Citation:
Wick, M., M. Wheeler, T. Hollenhorst, J. Fischbach, N. Martin, T. Bernthal, AND F. Fitzpatrick. Slowing the flow: Setting priorities and defining success in Lake Superior’s South Shore watersheds. St. Louis River Summit, Superior, WI, March 14 - 15, 2017.
Impact/Purpose:
This poster will inform regional stakeholders about recommendations for landscape-scale watershed restoration aimed at reducing peak flows in order to improve water quality across the South Shore of Lake Superior in Wisconsin. Based on an extensive literature review, these recommendations come with associated metrics and new datasets that now allow managers to better prioritize subwatersheds for restoration, as well as evaluate results of efforts in a more quantitative manner.
Description:
For over 60 years, watershed conservation efforts to improve water quality have largely focused on restoring and protecting hydrology under the mantra “slow the flow”. This approach seeks to reduce peak flows with landscape scale watershed restoration approaches that increase in-channel roughness, upland roughness, upland retention and infiltration. As the frequency of high intensity storms increases, we are compelled to improve methods to prioritize slow the flow efforts and measure success in the Lake Superior basin in Wisconsin. Relying on an extensive literature review, we identified metrics and associated thresholds for impacts to stream hydrology, and compiled the best available datasets to evaluate those metrics. Storage is one of the most important parameters in predicting peak flows. The recently-updated Wisconsin Wetland Inventory along with the Wetland Functional Assessment, which describes wetland functions like surface water detention based on geomorphological characteristics, allow enhanced evaluation of subwatershed storage and opportunities to increase storage. In addition, a Potentially Restorable Wetlands layer, available across the basin, identifies probable historic wetlands based on soils and topography. Along with basin-wide data on soils, stream slope, precipitation, and snowmelt; we can calculate subwatershed peak discharges and compare them to the threshold where impacts start to be observed. The availability of detailed land use data (NASS Cropland Data Layer, WiscLands2, etc.) allow us to evaluate subwatershed open lands compared to peak flow impact thresholds. With land use overlaid with land ownership data, we can identify actionable opportunities for conservation as well as identify priority actions tailored to the existing land use interests (agriculture, forestry, municipal, etc.) at the subwatershed scale. The increasing availability of high-resolution, spatially resolved datasets allows us to advance strategic efforts rooted in sound science to better implement and evaluate slow the flow efforts in the Lake Superior basin.