Stormwater Quantity and Quality Management Options in Rapidly Urbanizing Watersheds: The Case of Mbezi River Catchment in Dar Es Salaam-Tanzania

Abstract

Over the past two decades there has been a growing worldwide concern about the ability of urban infrastructure systems to withstand the increasing impacts of urban population and climate change. Akin to similar concerns, the objective of this paper was to evaluate stormwater quantity and quality management options in rapidly urbanizing watershed of Mbezi River catchment in Dar es Salaam-Tanzania using field investigations, public meetings and GIS techniques. Analysis results of capacity quantification of the proposed stormwater management components indicate that stormwater harvesting alone can disconnect up to 12% of stormwater runoff stream generated in the study catchment. In addition to other components, the proposed landscape-based stormwater management system puts more emphasis on rainwater harvesting, stormwater retention and detention elements to decelerate runoff speed and enhance more residence time for the runoff not only to infiltrate, but also to evapotranspire, while improving the scenery and aesthetic quality of the environment altogether.