Development of Water Allocation Optimization Model for the Sokoto-Rima River Basin using WEAP

Abstract

Water allocation for the Sokoto-Rima River basin has been modelled and Optimized with the use of WEAP-model. The water demands in the Sub-basins were aggregated to configure the WEAP-model using 2016 as the base year. A reference scenario (2017-2024) was developed from current account through the year 2024. The reference scenario therefore produced a total of 793.4 x 106 m3 as monthly average water demand and a projected yearly water demand accruing to a total of 7,140 x 106 m3 per day through 2024. The projected water supply projected to be 3,939 x 106 m3 with a total of 3,151.1 x 106 m3 unmet water demand per day through year 2024. What if scenarios were built on the reference scenarios to determine the impact of changes in parameters with which the models were calibrated. Population management, Water Management and reduction in irrigation water use and sourcing alternative water sources were the scenarios built, to identify their effect on the water allocation in the basin and how they will reduce the unmet demand in the entire basin as a whole. Projected yearly unmet demand for population management Scenario yielded a total of 272.0 x 106 m3 in 2017 to 4,432.2 x 106 m3 in the year 2056, Sourcing alternative water sources within the basin produced a projected unmet demand of 1,474.8 x 106 m3 as monthly averages for the whole basin, while reduction in irrigation water scenario has projected unmet water demand as 258.5 x 106 m3 in 2017 remained unchanged through 2056. It was discovered that WEAP performed well in optimizing water allocation in the basin studied as the scenarios simulated results impacted on the basin water allocation. Irrigation water use should be reduced through irrigation method change as well as other sources of water be sought and harnessed for improved water supply in the basin, these includes development of small dams to take care of specific purposes in the basin.