Hydrologic responses to climate and land-use/land-cover changes in the Bilate catchment, Southern Ethiopia

Abstract

The likely effects of climate and land-use/land-cover (LULC) changes on hydrologic processes in Bilate catchment, Ethiopia were evaluated. The study emphasizes the evaluation of individual and combined impacts on hydrologic responses of climate and LULC changes. Climatic scenarios included a downscaled regional climate model from CORDEX-Africa. The CA–Markov model was used to project LULC. The results revealed that distinct changes on hydrologic responses occurred which follow the direction of climate and LULC changes. A 30.87% decline in rainfall resulted in about 4.09, 1.43 and 3.57% decline in runoff, groundwater and water yield, respectively. A rise in mean temperature by 1.3 °C resulted in 7 and 0.8% increase in potential and actual evapotranspiration, respectively. Runoff, groundwater and water yield are projected to decrease by 11.24, 12.54 and 11.54%; however, potential and actual evapotranspiration are projected to increase by 19 and 14.7%, respectively, under combined climate and LULC changes. The joint effects of climate and LULC changes on hydrologic responses in the forthcoming were higher than the variation trend of climate or LULC change alone. Climate change compared with LULC change has a higher impact on hydrologic responses. The results obtained provide further insight into future water balance, assistance in water resources planning and management.

Impacts of land-use/land-cover changes on nutrient losses in agricultural catchment, southern Ethiopia

“…This agrees with a study by Du et al (2014) and Delkash et al (2018), who reported that urban areas usually enhance nutrient concentrations in water bodies. Besides, this result agrees with Kuma et al (2021), who reported that runoff could increase nutrients in surface water bodies due to an increase in the agricultural lands, urban and built-up areas.…”

“…The less dominant soils are Eutric Regosols (Fh1-3b-1156), Calcic Fluvisols (Fo91-2b-552), Calcaric Fluvisols (Fo90-2-3b-551), Luvic Phaeozems (Ao48-1a-1060) and Mollic Andosols (Vc14-3a-261). Three LULC maps for 1986, 2002 and 2018 developed by Kuma et al (2021) were used. We used Landsat imagery from TM, ETMþ and OLI for 1986, respectively to assess LULC changes in the Bilate catchment.…”

Integrated Watershed Management Framework and Groundwater Resources in Africa—A Review of West Africa Sub-Region

“…Watershed and groundwater management necessitates diverse skills and competencies; the strategic community engagement model comprises main stakeholders, government and non-government organizations, and other institutions [39,40]. The observed outstanding results on the groundwater runoffs are mostly due to easy access and quick advice to the farmers within the local communities and regions [41,42].…”

Envisaging the actual evapotranspiration and elucidating its effects under climate change scenarios on agrarian lands of bilate river basin in Ethiopia

“…Downscaled values cannot generally be used for effect evaluation since the projected elements may differ significantly from the recorded data ( Mutayoba and Kashaigili, 2017 ). The most popular techniques for predicting the consequences of global warming are general circulation models (GCMs), although their level of errors and uncertainty makes it difficult to simulate real climatic occurrences ( Green et al., 2011 ; Cannon et al., 2015 ; Bekel et al., 2021 ; Kumar et al., 2021 ; Mengistu et al., 2021 ; Ukumo et al., 2022 ). GCM simulations have enormous errors when compared to historical data.…”