Impact of the Gurara River (Nigeria) interbasin water transfer scheme on the Kaduna River at the Shiroro Dam

Abstract

The Kaduna River is impounded at Shiroro for the sole purpose of generating electricity. There is, however, a persistently low reservoir level between November and June due to seasonal fluctuations in the river inflows to the Shiroro Reservoir. A proposed scheme to increase Shiroro Reservoir storage is to transfer 1500 Mm3 of water (which is about 10% of the mean annual inflow to Shiroro Reservoir) from the Gurara River to the Shiroro Reservoir between December and May. The interbasin water transfer is intended to stabilize the Shiroro Reservoir level. This paper examines the effect of the water transfer on the storage level of this reservoir. Fourteen years of daily inflow record were used to study the real-time operation of the reservoir. The results indicate that with the water transfer, the reservoir attains its maximum operating level in July and maintains it until September or October, whereas the maximum operating level would have been attained in August without the transfer. Although the interbasin water transfer into the Shiroro Reservoir would enhance power generation, there would be an increase in the frequency and severity of annual flooding downstream of the dam. Appropriate flood damage mitigation measures are recommended for the Kaduna River basin to optimize the benefit of the proposed interbasin water transfer scheme.