It is industry best practice to split up the subcatchments in a model into their pervious and impervious areas when adopting the Laurenson (or RAFTS) runoff routing method ie U = 2 and U = 0. The current workflow to achieve this is to setup the model with 2 subcatchments representing the impervious and pervious surfaces within a subcatchment. Existing Innovyze software (ICM and XPSWMM/XPSTORM) provide the user the ability to split the area of a catchment up into a number of different runoff surfaces. A feature like this would be great to have for InfoDrainage.

The Rural Runoff estimate tool in MDSUDS does not allow values of SOIL below 0.15.
The UKSUDS greenfield runoff tool defaults to a value of SOIL=0.1 where SoilType=1
This produces a significant difference in results. This difference results from using values of SOIL from FSR vs Wallingford Procedure and FSSR7
It would be better if the MDSUDS tool allowed values of SOIL down to 0.1 for compatibility, and if the default values were standardised across the industry.