RTK Hydrographs (InfoWorks)

RTK Hydrographs can be specified as part of the subcatchment data and are used to determine RDII (Rainfall Derived Infiltration and Inflow) entering the system.

This method would typically be used to model the extra inflow during and immediately after rainfall events, caused by seepage of rainwater into defective pipes, ill fitting manhole covers etc.

The RTK Hydrograph defines the proportion of the rainfall falling on the subcatchment that enters the system as RDII and the time at which this rainfall enters the system.

If any monthly RDII information is available, then Monthly RTK Hydrographs can be defined in addition to the general RTK Hydrographs. Data in one or more Monthly RTK Hydrographs will override the data in any RTK Hydrograph (with the same ID) for the specified month.


Monthly RTK hydrogaph data will only be included in a simulation if the Use SWMM5 RDII option is selected in the simulation parameters.

RTK Hydrographs in InfoWorks ICM

RTK Hydrographs are defined using the RTK method. The RTK parameters are specified on the RTK Hydrograph or Monthly RTK Hydrograph Grid Window of the Subcatchments Grid or the RTK Hydrograph or Monthly RTK Hydrograph Property Sheet.

The RTK Hydrograph is associated with a subcatchment by selecting the RTK Hydrograph ID from the Subcatchment RTK Hydrograph field in the Subcatchment Grid Window of the Subcatchments Grid or property sheet.

When a simulation is run, the RTK Hydrograph or any applicable Monthly RTK Hydrographs are applied to the rainfall profile associated with the subcatchment, and multiplied by the subcatchment Contributing Area to give the resulting RDII into the subcatchment's node.

RTK Method


RTK Hydrograph Data Fields (InfoWorks)

Monthly RTK Hydrographs (InfoWorks)