APPLICATION OF WATER EVALUATION AND PLANNING (WEAP) MODEL TO ASSESS WATER DEMANDS IN RESERVOIRS: A CASE STUDY OF GOLINGA IRRIGATION SCHEME, TOLON

Abstract

This work focused on water demand and supply analysis of the water availability on the Golinga dam in the Northern Region of Ghana. Water Evaluation and Planning (WEAP) model was used for predictions of current and future water supply needs in the study area. The study utilized the WEAP model that integrated spatial, climate, and bathymetric information to characterize the study area. The results from the model revealed that water demand for the reference and Reduction in Reservoir Volume (RRV) scenarios were the same and projected to be 9.43×103 m3. Water demand for High Population Growth (HPG), Increase in Irrigable Areas (IIA), increase in per capita water demand, and combination of scenarios (HPG+IIA+RRV) were 9.83×103 m3, 13.43×103 m3, 10.5×103 m3,13.83×103 m3, respectively. The unmet demand for reference and Reduction in Reservoir Volume (RRV), High Population Growth (HPG), Increase in Irrigable Areas, increase in per capita water demand, and combination of scenarios (HPG+IIA+RRV) were 6.38×103 m3 6.65×105 m3, 9.91×103 m3, 7.11×103 m3, 10.18×103 m3. Based on the model output, irrigation demand is expected to compete with domestic demand in future, as a result of expansion of agricultural lands. Also, observation of land use shows the potential decrease of water resources within the catchment. Therefore, there is the need for strategic water management planning and management of the Golinga water reservoir.