I am modelling Green roofs as LIDs. Each subcatchment represents about 40 hectares of urban area. The current situation (without Green Roofs) is that 80% of the total area is Imprevious and 20% is pervious. When I include the Green Roofs, that will occupy a certain area of the subcatchment which is indicated in the "LID Usage Editor", where does the Model place this Green Roofs' area?? Does it consider that the GRoofs will substitute part of the Pervious area of the subcatchment? Part of the Impervious area? None (in this case I would be adding area to the subcatchment...)?
I hope the question is clear...
Thanks in advance!!