Incorporating infiltration modeling in urban flood management

Increasing flood risks in urban areas can be linked to increase in impermeable areas due tourbanisation as well as climate change, resulting to increased frequency of occurrence of floodevents. Management of storm water in such areas through conventional drainage systems resultsin both the reduction of rise time of peak flows and magnification of peak flows beyond those ofundeveloped catchments.In order to reverse the adverse effects of conventional drainage systems, we need to replicate thenatural drainage processes by integration of sustainable drainage systems in urban floodmanagement. Such systems encourage infiltration and storage of runoff flows.As the use of sustainable drainage systems increases in urban areas, so will the requirement fortheir effective design and implementation. The integration of modelling of such systems withinconventional drainage systems is vital in ensuring their effective implementation.As such, this study aimed at the incorporation of infiltration modelling in sustainable drainagesystems, namely the detention storage unit within the one-dimensional urban storm watermanagement model, EPA-SWMM 5.0. It was observed that by introduction of infiltrationmodelling in the storage, the flow attenuation performance of the unit was improved.In the past, sustainable drainage systems have been designed for individual sites. Thus, in thisstudy, the catchment scale impact of both source and regional control storage systems wasexamined. Based on the findings of two case study areas modelled with the proposed storageoptions, it was concluded that source control storage systems do have a greater impact at acatchment level, with respect to flow attenuation, compared to regional control storage systemswhose capacity is equivalent to the sum of source control storage capacity at the catchment