SWMM56

Note:   The surface  runoff  is a non linear function of the independent  depth  in both the pervious and impervious areas of the subcatchments.   No surface  runoff  occurs until the  depth  over either the impervious or pervious area is greater than the respective depression storage (Figure's 1, 2, 3 and 4). Figure 1:   Surface  Runoff ,  Depth  and  Depression Storage  Relationship . Figure 2:    Subcatchment   Runoff  and  Depth  over time with a  Subcatchment  Width of 500 feet. Figure 3:    Subcatchment   Runoff  and  Depth  in a Scatter Graph with a  Subcatchment  Width of 500 feet. Figure 4:    Subcatchment   Runoff  and  Depth  in a Scatter Graph with a  Subcatchment  Width of 2000 feet.