Abstract:
Climate change and land use/land cover (LULC) changes significantly threaten global water
resources, impacting socio-economic systems. This study aimed to evaluate the effects of
climate and LULC changes on the availability of surface water resources in the Baledweyne
watershed. This study utilized bias-corrected outputs from three climate models (MIROC-6,
MIROC-ES2L, and CMCC-ESM2) for the baseline period (1997–2022) and projected
scenarios for the 2050s and 2080s under shared socio-economic pathways (SSPs) 2.6 and 8.5
LULC changes were assessed using downloaded satellite Landsat images, which were
classified with the spatial analysis tool employing the supervised classification method.
Classified 1997, 2008, and 2017 LULC maps were used to evaluate their impact on surface
water availability. The LULC prediction was used in the Cellular Automata–Artificial Neural
Network (CA–ANN) model, incorporated in the MOLUSCE plugin of QGIS. The Soil and
Water Assessment Tool (SWAT) was used within the ArcGIS interface to simulate and analyze
climate and LULC changes. Results indicated an increase in agricultural land by 58% and
urbanization by 6.23%, alongside decreases in rangeland by 3.93% and forest land by 6.66%.
The model demonstrated good performance during calibration and validation, showing strong
agreement between simulated and observed streamflow, with calibration metrics of R² = 0.89,
NSE = 0.83, and PBIAS values of 15 and -0.5. Under SSP1 2.6, an average rainfall increase of
22.79% was predicted for the mid-term and 8.23% for the long-term. In contrast, SSP5 8.5
projected an average rainfall increase of 23.4% in the mid-future and 2.79% in the long term.
The mid-term maximum and minimum temperatures were projected to increase by 2.8°C to
2.1°C under SSP1 2.6 and by 3.1°C to 2.9°C under SSP5 8.5. In the long term, increases were
projected to be 3.1°C to 1.6°C for SSP1 2.6 and 2.8°C to 1.6°C for SSP5 8.5. Additionally, the
analysis indicated an increase of surface runoff by 6.38% in the mid-term and 7.52% in the
long-term, while Evapotranspiration also increased by 3.05% in the mid-term and by 11.1 %
in the long-term. The impact of future climate change resulted in a positive change in water
availability in all seasons associated with increased precipitation. These changes can
significantly affect the watershed, requiring careful management to mitigate negative impacts.
