Abstract
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.
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