Author(s): Hans G. Rob; Jan Atle Roti; Haakon Libaek
Linked Author(s):
Keywords: Songwe River; River stabilization; Flood mitigation; Morphology; Reservoirs
Abstract: The Songwe River forms part of the physical boundary between the Republic of Malawi and the United Republic of Tanzania and has a length of approroximately 200 km. The meandering river course significantly affects the environment and the living conditions of the inhabitants of the Songwe River basin. Floods inundate more than 9,000 hectares of frtile land seasonally. Bank erosion is responsible for loss of land in the order of 25 ha per year in the lower floodplain area. Specific objectives of a bilateral project between the two governments are to (1) determine both technically and economically, the best optional method for stabilizing the course of the Songwe River, thereby ensuring a stable and definitive international boundary between the two countries; and (2) prepare a Songwe River Basin Development Plan for the development of hydropower, irrigation, land reclamation, river training etc. as part of ensuring the success of objective (1) above. The combination of multi-purpose reservoirs in the upper river basins and bank protection works along the lower reaches has been investigated at a feasibility level. Study results with detailed mathematical modeling show that management of the frequency and duration of short-term flood events (by means of reservoirs in the middle and upper part of the Songwe River Basin) has a pronounced effect on the overall bank erosion and thereby river stability in downstream reaches.
Year: 2004