Evaluating the implications of future water resources development under current and projected future climate in the Volta Basin

This study combines climate change (CC), hydrological and water resource evaluation models to assess the impact of one downscaled mid-range CC scenario (A1B) on the performance of existing and planned irrigation and hydropower schemes in the Volta basin. The models were run (1983-2100) to simulate the CC scenario in combination with three development scenarios, each reflecting different levels of water resource development in the basin. Results indicate a general trend of declining rainfall and increasing potential evapotranspiration in the basin. This trend was found to have caused: i) a significant reduction in flows at key stream gauge locations; ii) an increase in average basin-wide per hectare irrigation requirement and iii) a significant reduction in the percentage of the potential hydropower that could be generated in the basin. This has the tendency to undermine the economic development of the riparian countries unless due consideration is given to these impacts and suitable adaptation measures introduced