The Subcatchment Manager of InfoSWMM will help calculate most of the physical parameters associated with a Watershed or Subcatchment in SWMM 5 from a Digital Elevation Data (Step 1). The Subcatchments area created from a Flow Direction Raster (Step 2) and a Flow Accumulation Raster (Step 4) after filling in any Sinks in the DEM (Step 3). The created watersheds (Step 5). The physical parameters estimated from the DEM are shown in Figure 1.
Figure 1. Physical Data Estimated from a DEM using the Subcatchment Manager in InfoSWMM.
Step 1. Find, Create or Otherwise Locate a TIN, DEM or DTM for the project area with elevation data that you can use with the InfoSWMM Subcatchment Manager.
Step 2. Create a Flow Direction Raster using the Watershed Command.
Step 3. Check to see if there are Sinks in the Elevation Data that have to be filled using the Filled Sink Command.
Step 4. Create a Flow Accumulation Raster
Step 5. Create the Watersheds from the Flow Direction and Flow Accumulation Rasters.
