Mapping Soil Hydrologic Conditions Using Soil Survey, Environmental Data, and Spatial Disaggregation Techniques.

On the Delmarva Peninsula, which includes the Eastern Shore of Maryland and Virginia and most of Delaware, there is pressing need for more spatially detailed soils maps to support the assessment of wetland ecosystem services at a landscape scale and enhance the implementation of wetland conservation and restoration practices. With the recent acquisition of high resolution LiDAR for the entire Delmarva, finer scale depiction of soils on low relief landscapes of the region may be possible. Using soil-landscape relationships described in soil survey, LiDAR and other environmental data, we are developing a method to digitally disaggregate SSURGO soils data to improve our ability to identify hydric soils and map soil properties on depressional wetland landscapes within the Choptank River Watershed.  As part of this approach we are deriving a set of topographic metrics from LiDAR DEMs to discern subtle variations in topography and describe landform shape.  These include primary metrics such as slope, curvature, and local relief to depict landform shape; and secondary variables such as topographic wetness index to characterize soil moisture across the landscape. Numerous neighborhoods for landform attributes and multiple flow direction algorithms for calculation of TWI will be tested.