Source Control Measures for Stormwater Runoff in Urban Areas

Abstract

Stormwater runoff in urban areas has been handled up to now mostly according to the principle: “Stormwater runoff has to be discharged as fast and as completely as possible in order to avoid or to diminish damages or inconveniences caused by flooding or water ponding within settlements”. This principle is implemented in the design of sewer systems, either combined or separated. Although sewer systems successfully achieved the protection aims in the past, their disadvantages increased recently. The overloading of sewer systems as a consequence of connection of developed areas leads to a cost intensive extension of sewer systems and wastewater treatment plants. Further, there is a loss of groundwater recharge in urban areas. And last but not the least, the impacts of sewer systems on the receiving waters regarding quantities and pollution loads became more important and cannot be tolerated any longer. Consequently, such impacts have to be reduced. Hence, the attitude towards stormwater runoff is going to change. Application of source control measures instead of mere stormwater discharge wherever possible is going to become the new principle.