Note:  How to Use the Arc Map Editor in InfoSWMM

Step 1 is to use the Edit Feature for example the Subcatchment layer to bring up the Arc Map Editor Tool.

Step 2 is to use the Reshape Feature tool or Vertex tools to bring together mis matched Subcatchment Boundaries

Step 3 is to use save the edits and then Update the DB from the Map to recalculate the area of the Subcatchments