Abstract:
Climate change has the most severe consequences on water resources, particularly
hydrologically sensitive areas such as the Borkena catchment in central Ethiopia. Increased
temperature and shifted precipitation regimes have enormous projected impacts on
groundwater recharge, surface runoff, and evapotranspiration, the most vital parameters of the
hydrologic cycle. Climate change impacts on groundwater recharge over past (1993–2022) and
future timescales are analyzed in this study based on the WetSpass model. The trend of
observed and projected climate was calculated using the Mann-Kendall test and Sen's slope
estimator, while future trends under RCP4.5 and RCP8.5 were derived from the MIROC5
model and bias-corrected via the linear scaling method. In historical trends, temperature
increased and rainfall decreased. In RCP4.5, future precipitation is 9.92% and 13.5%, and
temperature is 2.58°C and 3.22°C in the mid- and long-term, respectively. With increased
rainfall, recharge will decrease by 8.7% and 6.8%, possibly because of increased
evapotranspiration and temperature. Runoff and AET are projected to increase by 10.2% and
19.7% in the mid-term, and by 12% and 22.5% in the long-term under RCP4.5. For RCP8.5,
rainfall will rise by 21% and 37.8% and temperature rise by 3.6°C and 6°C. Recharge will go
down by 5.33% during the mid-period but grow highly by 39.7% during the long-period.
Runoff will go up by 14.8% and 31.4% in midterm and long-term respectively, and AET go
down highly by 47% during the mid-period and then grow by 50.5% during the long-period.
In conclusion, the study points out the extreme vulnerability of other water balance components
and groundwater recharge in the Borkena catchment to climate change and demands immediate
proactive and adaptive water resource management measures to reduce these impacts
Description:
ASSESSING THE IMPACT OF CLIMATE CHANGE ON GROUNDWATER RECHARGE
IN BORKENA RIVER CATCHMENT, AMHARA REGION, ETHIOPIA
