There are Four factors in Rainfall Dependent Infiltration and Inflow or RDII in SWMM 5

There are Four factors in Rainfall Dependent Infiltration and Inflow or RDII in SWMM 5:

1.   The fractional response to Rainfall or R from 0 to 1
2.   The Time Base of the Unit Hydrograph or T in hours * Dimensionless K Shape Factor
3.   The Sewershed Contributing Area in acres or hectares and
4.   The Maximum, Initial Abstraction and Recovery Rate for R on a Monthly Basis in units of inches, mm or mm/day,
5.   The fifth and probably the most important factor is the Rainfall