How are the Soil and Subcatchment Tables Used in InfoSWMM and H2OMap SWMM?

If the soil is not present in the subcatchment its field can be left blank or the coverage value could be set to zero. How are the Soil and Subcatchment Tables used in InfoSWMM

Note: How are the Soil and Subcatchment Tables used in InfoSWMM

There are seven possible sets inputs for the CN’s and the Hydrology Method:

1. You have a CN in the Soil and Subcatchment Tables and UH is selected but not CN infiltration as the infiltration option– the CN in the Subcatchment Table is used for the UH Runoff and the UH Losses. Either GA or Horton Infiltration is exported but not used.

2. You have a CN in the CN in Soil and Subcatchment Tables and UH is selected and CN infiltration is selected as the infiltration option – the CN in the Subcatchment Table is used for the UH Runoff and the UH Losses. The choice of CN Infiltration is exported but not used.

3. You have a CN in the Soil but not the Subcatchment Table and UH is selected but not CN infiltration – this will NOT solve as the CN is blank or missing in the Subcatchment Table.

4. You have a CN in Soil but not the Subcatchment Table and UH is selected and CN infiltration is selected – this will NOT solve as the CN is blank or missing in the Subcatchment Table.

5. You have a CN not in the Soil but in the Subcatchment Table and UH is selected but not CN infiltration – this will solve using the CN from the Subcatchment Table the infiltration will be zero in the output for all Subcatchments.

6. You have a CN not in Soil but in the Subcatchment Table and UH is selected but CN infiltration is selected – this will solve using the CN from the Subcatchment Table the infiltration will be zero in the output for all Subcatchments.

Figure 1 EPA Non Linear Reservoir Modeling and Unit Hydrograph Options

7. If Non linear reservoir routing is selected then one of the three infiltration methods is used and the infiltration values are from the Soil Table.

Figure 2. Here is how the two DB Tables work together if you use UH Runoff or the two NRSCS methods