Affiliation:
1. a Department of Civil Engineering, College of Engineering and Technology, Mbeya University of Science and Technology, P.O. Box 131, Mbeya, Tanzania
2. b Department of Water Supply and Irrigation Engineering, Water Institute, P.O. Box 35059, Dar es Salaam, Tanzania
Abstract
ABSTRACT
As cities expand, changes in land use increase the runoff quantities. Impermeable catchment areas contribute to peak flows, causing floods in insufficiently capacity river reaches. The rate of urbanization witnessed in the Kinyerezi River catchment in Dar es Salaam has contributed to floods in the Msimbazi River. The low-impact development (LID) practices that include bioretention (BR) ponds, rain barrels (RBs), rain gardens (RGs), vegetative swales (VSs), constructed wetlands (CWs), etc., can be utilized to mitigate a portion of the surface runoff. This study aims to quantify the suitable LID practices for the Kinyerezi River catchment in mitigating a portion of runoff floods. The sub-catchment physical characteristics and soil infiltration rates (Ks) were matched with each LID sitting requirements and later by multi-criteria decision-making (MCDM). The results on matching sub-catchment characteristics and LID sitting requirements indicated that BRs, RBs, VSs, RGs, and CWs were the preferable LIDs while MCDM analysis indicated the BRs, RGs, and RBs more appropriate. The BRs, RGs, and RBs were quantified to be 101, 3,698, and 3,698, respectively, within the catchment. BRs are recommended for catchment use while RBs and RGs are recommended for residential buildings. The RBs have the advantage of promoting water-demanding economic activities.