SCS Infiltration Method

SCS Infiltration Method

It is possible to use SCS infiltration without using the SCS hydrology method. Refer to the SWMM5 hydrology manual for the implementation.

  • SWMM5 doesn’t support the use of initial abstraction, which is the equivalent of setting initial abstraction as 0 in XPSWMM
  • XPSWMM doesn’t support the recovery of the infiltration capacity. For a single event simulation, this makes no difference
  • ICM is similar to XPSWMM that is supports the inclusion of the initial abstraction but does not support recovery of infiltration capacity.

SWMM Model

We have a single subcatchment 100% pervious without any depression storage.

XPSWMM Model

For the XPSWMM model, it has the same setup as SWMM5 except for the SCS infiltration we need to set initial abstraction as 0 (7) to match what SWMM5.

InfoWorks ICM

Curve number is defined in two places in ICM. CN number is defined in the subcatchment property(left), and the rest is defined in the runoff surface for pervious land cover (right). To be consistent with the SWMM5 method, we set initial abstraction to 0, we set the initial loss to 0 for the runoff surface.

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