RDII Intial Abstraction in SWMM 5

Subject:  RDII Initial Abstraction in SWMM 5

 The initial abstraction in each of the three components of RDII in SWMM 5 are updated at each time step.  The initial abstraction (ia) is:

 ia = iaMax - iaUsed

 based on the maximum amount of ia, the ia used (iaUsed), the recovery rate (iaRecov) and the month and class of RDII.  You can enter a value for iaMax, iaInit and iaRecov for each month.

The iaUsed at the beginning of the simulation is set equal to iaInit

and if there is no rainfall