The Bui Hydropower dam located in the Black Volta basin plays an important role in the socio economic development of Ghana. The availability of water in the water basin is useful for irrigation, power generation, and livestock and for domestic use.
This study, firstly evaluates the land use land cover change over the Black Volta basin for the years 1986, 2000 and 2014 using Landsat data, and analyzes historic observed rainfall, stream flow and temperature variability for 1982-2011. It also assesses the potential impact of land use land cover change on stream flow at Bui station. Using the Water Evaluation and Planning (WEAP) system model, it evaluates the potential effects of land use land cover change combined with climate change on the Bui dam area under four different scenarios. The study has shown that the land use and land cover has changed faster in Black Volta basin due to increase in population growth rate which impacted the Bui streamflow. It was found out that the stream flow varied much more than the rainfall, annually, periodically, seasonally and monthly except for the dry season, this is due to land cover and land use change in the basin. For the period of 1986 -2000, the land use has increased by 12.7% and the rainfall has increased by 14% while the stream flow has increased by 44%. However, for the period 2000-2014, the land use has increased by 59.9% and the streamflow has increased by 67% despite the decrease in rainfall about 0.16%.
Therefore, the change in land use has changed the Bui stream flow dynamic and this change led to increase the stream flow and may favor Bui hydropower production. Moreover, it is observed that rainfall and streamflow variability follow the same pattern. In one hand, the climate change alone is promised to decrease the Bui power production under any changing climatic condition for the projected period 2012 to 2040. The land use land cover change is promised to reduce the negative effect of climate change on the Bui Hydro power production. Climate change under current condition is promised to decrease the energy production by 23.2% with No LCC while with LCC it will decrease by 2%. Climate change under dry condition is promised to decrease the energy production by 54% with No LCC while with LCC it will decrease by 46%. Climate change under wet condition promised to decrease the energy production by 0.15% with No LCC while with LCC it will increase by 40%.
Therefore the LULCC under climate change condition is promised to favor the Bui hydropower production, but the main OBAHOUNDJE S. M, 2015 problem with LULCC is that it leads to soil erosion and sedimentation which can lead to siltation of the Bui reservoir and can damage the Bui hydropower turbine respectively.