| dc.description.abstract | The global hydropower sector relies on surface water flows of substantial and predictable
volume, which makes it vulnerable to climate change. This study focused on assessing the
risks posed by climatic factors on river flow regimes and their impact on future hydropower
production in the Shire River Basin. The study employed Mann-Kendall test and Sen's slope
estimator to detect climatic trends in the time series data and estimate the magnitude of the
trend. Future river flow regimes were analysed using HEC-HMS by integrating future
climatic projections data from CIMP6 models under ssp2-4.5 and ssp5-8.5 scenarios. The
performance of the climate models was evaluated using the Coefficient of Determination
(R2), Nash Sutcliffe Efficiency (NSE), Root Mean Square Error (RMSE) and Percent Bias
(PBIAS), Including a Pearson Matrix Scatter Plot for the historical data to check how well
the models represented the study area. Similarly, the hydrological model’s performance was
assessed using the NSE and R2 of the simulated flows against the observed. Flow Duration
Curves were used to assess the future impacts of the river flow regimes on hydropower
generation at low flow regimes. Mann-Kendall results showed a significant increasing
rainfall trend for 68% of the stations in the basin. Minimum temperatures did not show any
significant trends, whereas all stations showed a significant increasing trend for maximum
temperatures. Both climate and hydrological models showed good performance in
representing observed data. Future rainfall patterns indicated a general increase of 13-28%
in wetter months, and a decrease in drier months of 3-8% under all scenarios, with a more
notable increase in the 2030-2064 period under ssp5-8.5. Future river flow regimes took a
similar pattern as rainfall, with a marked increase in all scenarios, but particularly very high
under ssp5-8.5 but showing lowest flows in the drier months in the 2030-2064 period. High
flows highlight the potential of flooding events in the basin which could affect the
hydropower equipment, but could also increase the potential of the sector. Frequency
analysis on the low flows, shows susceptibility of the hydropower sector to climate change
as it is projected to cause low power generation. The findings from this study underscore the
importance of diversifying the energy mix, while protecting the hydropower infrastructure
from potential flooding events | en_US |
