Water Resources Development in the Mbuluzi River Basin

Abstract

The Mbuluzi river basin originates in Swaziland and exits in Mozambique. The mean annual runoff is estimated to be 372x10 m. The highest recorded flow is 68m/s while the lowest flow is 1.1m/s. The current water demand is estimated to be 8.14m/s while the projected water demand excluding irrigation water demand is 8.5m/s. From the above information it means that, the available water resource is not able to meet the demand especially during winter months. The required reservoir capacity to meet the projected water demand (year 2020) has been estimated to be 212x10 m. The design capacity of the Mnjoli reservoir which was completed about twenty years ago is 152x10 m. Therefore, the additional required storage to meet the demand is 60x10m. However, due to over grazing activities upstream of Mnjoli dam, it is assumed that a great deal of the live storage has been used up by sediment accumulation. Therefore, the suggested additional reservoir storage capacity should be 120x10 m, assuming that 40% of the reservoir is now full of sediments.

UNISWA Research Journal of Agriculture, Science and Technology Vol. 4 (1) 2000: pp 27-33