Geoinformatics Approach to Water Allocation Planning and Prognostic Scenarios Sustainability: Case Study of Lower Benue River Basin, Nigeria

Water allocation planning in an equitable and sustainable way is intrinsically complex. This study proposes a water resource allocation system using an integrated Soil and Water Assessment Tool and Water Evaluation and Planning tool (SWAT-WEAP) model for hydrological simulation and prognostic scenarios sustainability prediction. The study explores the use of Digital Elevation Model (DEM), soil and land raster image in deriving physiographic information for land degradation impact assessment, quantification of optimal water allocation and generation of minimum ecosystem water requirement. Consequently, the SWAT quantifies the catchment water yield before been allocated optimally based on percentage dependable flow rates of 70% and 85% reliability flow regime at Makurdi, Nigeria discharge station. The WEAP model assesses the water resources utilization following scenarios adaptation by riparian users. Both models performed satisfactorily for streamflow and water yield prediction and resource sharing both in the calibration and validation phases with a correlation coefficient (R²) of 0.57–0.74 and root squared error (RSR) of 0.66–0.82. The results show how drainage network, channel length, drainage boundary, slope, and sub-catchment geometric properties demonstrate Geographic Information Systems (GIS) utility in morphoclimatic impacts assessment as a data management, scenario analysis, and decision support tool in water management for the Lower Benue River Basin, Nigeria. Planners and decision-makers need to consider several integrated plans as alternatives to adapting to climate change impacts and anthropogenic human activities in resolving the unmet demands.