An Assessment of Climate Change Impact on Water Related Ecosystem Services (WRES) including Hydropower Potential in the Dano Catchment (Volta Basin)

Abstract

This study assesses the impact of future climate change on water related ecosystem services (WRES) including hydropower potential in the Dano catchment (Volta basin). The Catchment covers an area of 196 Km² and is located in the Southwest of Burkina Faso in West Africa. Based on hydro-meteorological variables data collection such as discharge, precipitation, temperature etc. the conceptual rainfall-runoff model HBV light was successfully calibrated and validated for the catchment. The results indicate acceptable to very good model performances during the calibration (NSE = 0.945, R² = 0.945, and KGE= 0.948) and validation (NSE = 0.648, R² = 0.798, and KGE= 0.551) for discharge demonstrating a good agreement between observed and simulated variables The projected climate change signal in the catchment was examined using the representative concentration pathways 4.5 (HadGEM2-ES, GFDL-ESM2M) of WASCAL high-resolution regional climate simulation between a refence period and two future periods (2020-2049 & 2070- 2099). Compared to the reference period of 1985-2005, both climate models (data bias corrected) show an increased temperature of 1.9 to 2.8 °C by 2020-2049, and at the end of the century 3.2 to 5.4 °C. For precipitation the trend up will increasing to 10 to 30 % in the middle of the century and between 37 to 51.4% towards 2100. The potential evapotranspiration will increase by 2.3 % 5.3% by 2049 and of 4.1 to 8.8 % at the end of the century. The projected annual discharges change signals, show an increase of 25 % to 68 % by 2049 and at the end of the century this increase reaches 80.65 % to 109 %. The analysis shows that the precipitation, temperature and evapotranspiration change indicated that streamflow is more related to precipitation than to temperature. The effect of climate change on water related ecosystem services was assessed using discharge discharges simulated from the application of the two climate datasets (GFDL-ESM2M and HadGEM2-ES) and the validated HBV model. The simulated hydrological changes were translated into changes in WRES provision (hydropower, domestic water consumption, crop water availability even the ecological flow). The projected discharge increase will translate in an increase of all explored WRES in the future except the satisfaction of additional domestic water use that will decrease because of population growth. Therefore, the projected increase in future discharge will not be sufficient to counter balance the dd additional water demand associated to population development. These results imply adopting efficient water use techniques and harnessing the highlighted WRES potential in the catchment