Describing Aquatic Habitat with the River Bathymetry Toolkit

Recent advances in remote sensing technology have enabled digital morphologic mapping of large extents of stream networks. These synoptic data have relatively high resolution, precision and accuracy, and present opportunities to inventory or sample and monitor channel topography and physical habitat over an unprecedented range of spatial scales. However, manual interpretations of such extensive data are tedious and often somewhat subjective. We have developed an open access GIS-based tool suite, the River Bathymetry Toolkit (RBT), which will interrogate high-resolution stream and floodplain DEMs and quantitatively describe the channel topography. The RBT has modules to define standard at-a-station hydraulic geometry metrics at any water stage as well as the channel gradient and sinuosity. RBT information can be explored by cross-section or longitudinal profile. Cross-section data can be directly exported to the HEC-RAS one-dimensional numerical flow modeling software. The toolkit is being expanded to map physical habitat, such as the locations and characteristics of residual pools. We demonstrate examples of using the RBT to define distinct channel geomorphic domains and the qualities and homogeneity of physical habitat within individual domains.