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Simulation modelling for integration of hydropower, irrigation water and water supply potentials of Lweya Basin, Malawi

2019; Taylor & Francis; Volume: 19; Issue: 4 Linguagem: Inglês

10.1080/15715124.2019.1683854

1814-2060

Thomas L. C. Phiri, Deogratias M. M. Mulungu,

Water-Energy-Food Nexus Studies

The Nkhata Bay district in Northern Malawi faces rapid population growth, thus rising water demands for services such as agriculture production, water supply and electricity. Lweya River basin covers about two-thirds of the district and is the main water source for gravity-fed irrigation, water supply schemes, and a potential of gravity hydropower generation. However, there is no framework to support the decisions on water uses in the basin without adversely affecting downstream uses. Therefore, this study used simulation modelling to integrate the development and management of the surface water resources projects in a sustainable manner in the basin. The Soil and Water Assessment Tool (SWAT) model calibration results gave NS = 0.71 and R2 = 0.76, and NS = 0.80 and R2 = 0.86 on a daily and monthly basis, respectively. The model was used for integration where the simulated flow enabled estimation of Flow Duration Curve indices at short records and ungauged project sites, which were compared with potential water demands of 0.73, 8.61 and 20.52 m3/s for water supply, irrigation and hydropower, respectively. The integration of potentials used priorities set in Malawi's Water Resources Management Policy and Strategy (1994). Between the options, the best scenario was hydropower development located upstream of other uses on the main Lweya River.