This command routes runoff through branches, structures and reaches created with the following commands:
The routine supports the older and newer versions of TR-20 that are more Windows-compatible and you are prompted for storm data:
Rainfall Depth: Indicate the amount of rainfall that contributes to the hydrograph.
Main Time Increment: When using the TR-20 methodology, indicate the Time increment.
Storm Type: When using the TR-20 methodology, indicate the Storm Type that should be used for the calculations.
Antecedent Moisture Conditions: When using the TR-20 methodology, indicate the amount of moisture already in the soil.
Use DELMARVA 24-Hr Dimensionless Hydrograph: When enabled and when using the TR-20 methodology, a DelMarVa 24-hr Unit Hydrograph will be applied to the hydrograph calculations.
After the dialog, select the flow lines, structures and reaches that were created by the commands outlined above. The program then creates a TR-20 input file called temp.dat in the Carlson EXEC directory and runs TR-20. The output can be sent to a file, printer or screen from the report viewer.
Hydrographs are created at each flow line junction, structure and reach. The hydrographs are stored in files with a .h1 extension. These files are named automatically and placed in the project directory. Hydrographs entering a structure start with an 'S' and then the structure number. The structure number is labeled next to the structure symbol. Hydrographs entering a junction start with a 'J' and then the junction number. The junction number is also labeled next to the junction.
The next part of the file name is either 'RUN' for runoff, 'OUT' for the hydrograph at the end of the Watershed schematic with two flow lines, one structure and two reaches to be used as input for Hydrograph Development structure, 'REA' for the end of a reach, or 'ADD' for the combination of two hydrographs. A more detailed description of the hydrograph is in the third line of the hydrograph file. The Hydrographs can then be plotted using Draw Hydrograph.
Select flow polylines, structure and reach
symbols.
Select objects: Pick the objects to be used for the hydrograph
Pulldown Menu Location: Watershed → TR-20 Routing
Keyboard Command: runtr20
Prerequisite: A flow polyline