Management Of Stormwater Assets, Flooding Impact Of Stormwater Runoff Using PCSWMM In The Greater Durban CBD Area, South Africa

Urbanisation affects the quantity and quality of stormwater run-off because of the varied activities that an urban area generates therefore resulting in potential pollutants at or near land surfaces & is accentuated when the area is fully developed. Urbanisation also increases the volume of surface water run-off which decreases run-off times and leads to higher velocities and peak flows in drainage assets.

Stormwater drainage systems (open channels, culverts, pipe networks, manholes etc.) are managed by municipalities, utilities and departments of transportation (DOT’s) to collect rainfall, control storm peak flow and reduce the risk of flooding during extreme storm events.

Effective management of drainage systems are especially critical in the era of climate change and rapid urbanisation, when more frequent and more intense than normal floods are expected to occur. Asset management offers an alternative to the crisis management approach to dealing with drainage infrastructure failures in the aftermath of floods.

This paper deals in the stormwater drainage asset management, including defining inventory data requirements, developing condition assessment methods that consider both hydraulic capacity and physical conditions of drainage assets, and integrating inventory and condition data and documents in the geographic information system (GIS) framework.

The Developed GIS framework and stormwater modelling was applied to the stormwater drainage system in Durban’s CBD, South Africa. In the short term this framework can help municipalities to focus on data that is sufficiently detailed and useful for asset management but not so demanding of time and resources.

The long-term benefits through holistic planning are more cost effective strategies for preserving and improving drainage systems and for reducing the risk of costly flooding in an urbanised area.