Abstract:
Ethiopia's Bilate sub-basin is highly vulnerable due to a number of factors, including shifting
land use and land cover, erratic rainfall patterns, frequent climate changes, and rising
temperatures. These variables may have a significant impact on evapotranspiration, runoff,
river flow conditions, groundwater recharge, storage, and water level fluctuations.
Greenhouse gas emissions, agricultural expansion, poor land use management, and extensive
deforestation contribute to significant effects on the water balance systems of the sub-basin.
Previous studies and recent field observations indicate that groundwater levels in deep
boreholes are declining. However, the local community lacks technical knowledge about
perennial water resources and river flow conditions in ungauged catchments. The study also
observes that predictions of the effects of climate change on actual evapotranspiration and
groundwater recharge rate, as well as evaluations of groundwater storage anomalies, have not
been investigated in this sub-basin. The main objective of this research is to raise awareness
of the rainfall-runoff and flow conditions of the Bilate River in an ungauged catchment,
actual evapotranspiration, groundwater recharge, and trace the groundwater storage
anomalies under the effects of climate change and anthropogenic stresses by coupling
Station-based hydro-climatic data, including precipitation, temperature, wind, humidity, and
radiation, were collected from the Ethiopian National Meteorology Agency from 1989 to
2020, along with stream flow data and well completion report data from the Ethiopian
Ministry of Water Resources and Energy. Spatial data, including soil texture, topography, and
slope data, were also used for this study. Projected precipitation and temperature were
acquired from the CORDEX Africa platform using RCP4.5 and RCP8.5 scenarios. Static
groundwater water levels data from 16 wells were measured using a dip meter.
GRACE/GRACE-FO terrestrial water storage data from JPL, CSR, and GFZ, GLDAS data
including SMS P, Q, ET, and CWS from CLM, NOAH, and VIC portals were obtained. The
study employed R-programs, Arc-GIS-10.3, ENVI-5.3, and ERDAS-2015 for land use land
