This page describes the outputs within VBET projects.
Relative Likelihood of being Valley Bottom
This output is a raster, where each cell is an average value of the three topographic evidence rasters (Slope, TWI, HAND). The higher the value, the greater the likelihood that the cell is part of the valley bottom. This raster can be thresholded to extract a valley bottom polygon.
Valley Bottom Extent
This output is an estimation of the spatial extent of valley bottom for the watershed. It is comprised of polygons, which are generated by thresholding the likelihood raster. The default value used is 0.68.
Valley Bottom Geomorphic Units
- Estimated active channel: This area is represented using the channel area polygon tool input.
- Estimated active floodplain: This is the area where the relative likelihood of being valley bottom greater than 0.9.
- Estimated inactive floodplain: This is the area where the relative likelihood of being valley bottom is less than 0.9 but greater than 0.68. These threshold values my be adjusted based on more detailed calibration to achieve higher accuracy of classification.