Potential Wetland & Riparian Occurrence

This GIS model of potential wetland habitat occurrence across all of Idaho was based on compilation of existing land cover maps: • wetland and riparian ecological systems mapped by NW ReGAP (2010; http://gap.uidaho.edu/index.php/gap-home/Northwest-GAP/landcover/) • wetland and riparian ecological systems mapped by NatureServe (2005) • named swamps • named springs • geothermal springs (Idaho Department of Water Resources) • National Hydrographic Dataset springs and seeps • National Hydrographic Dataset swamps and marshes • National Hydrographic Dataset playas • water source springs (Idaho Department of Environmental Quality) • National Wetlands Inventory • hydric soils • streams Any vector layers were converted to raster layers (30 m2 pixels). The layers were then stacked into one layer representing the potential occurrence of wetland habitats across Idaho. After the model was built results were checked at known wetland sites using aerial imagery. The model tended to overestimate the extent of wetland habitats due to the inclusion of ecological systems occurring in both upland and wetland settings, as well as certain hydric soils. These systems and soil types were removed from final map. This model allows for all potential wetlands across the state to be assessed equally and objectively. It is important to note that this model has been ground-truthed in only small areas of the state and not for all types of wetlands. Where tested against known sites, it correctly predicts the presence of wetlands 80% of the time. The map should not be used to determine the actual boundaries of wetlands, but it can be used as a guide to predicting where wetlands are most likely to occur. Report Idaho’s landscape-scale wetland condition assessment tool— Methods and applications in conservation and restoration planning