" ) B " ) E " ) " ) K " ) F " ) E " ) NN " ) KK " ) N " ) K " ) BB Sand Lake Upper Couderay River Watershed Data Sources ± 0 2 4 6 1 Miles WASHBURN COUNTY SAWYER COUNTY The Stream Power Index (SPI) is a measure of the erosive power of flowing water. SPI is calculated based upon slope and contributing area. SPI approximates locations where gullies might be more likely to form on the land- scape. SPI is calculated using the following equation: SPIi = ln(DAi * tan(Gi)) where SPI is the stream power index at gridcell i, DA is the upstream drainage area (flow accumulation at gridcell i multiplied by gridcell area), and G is the slope at a grid cell i in radians. Tax parcels from the Sawyer County Land Records Department, acquired June 2016. Agricultural Tax Parcels selected by tax assessment attributes indicating agricultural land use. Agricultural land uses on parcels with tax exempt status are not included. Map crafted by Kyle McNair, edited by Douglas Miskowiak. Version 12-09-2016. BASS LAKE BIRCHWOOD COUDERAY EDGEWATER HAYWARD HUNTER LENROOT ROUND LAKE SAND LAKE STINNETT STONE LAKE 77 70 70 27 Stream Power Index Upper Couderay River Watershed Sawyer and Washburn Counties, WI Project Cooperators Project Education and Assistance _ _ _ _ _ _ _ _ _ _ _ _ C o u d e r a y R i v e r G ri n d s t on e C r e ek Si s s a ba g a m a Cr e e k O s p r e y C r e e k Grindstone Lake Lac Courte Oreilles Round Lake Sissabagama Lake Whitefish Lake Agricultural Tax Parcels Cranberry Operators High Erosion Vulnerability Low Erosion Vulnerability Stream Power Index - Vulnerability to Gully Erosion Watershed Boundary County Roads A State Roads 70 Minor Civil Divisions County Boundary Surface Waters Streams & Flow Direction _ Lac Courte Oreilles Reservation