Global climate change seriously impacts hydrological regimes, substantially impacting water resources and national food security. This study aimed to analyze the effect of climate and land use land cover (LULC) changes on catchment hydrological response for the Gelana River in Ethiopia. LULC images were developed through a supervised classification technique using the ERDAS platform, ArcGIS, and the cellular Automata-Markov model. The study highlighted significant land-use changes, with increased agriculture and built-up areas at the expense of forests and pasturelands. Coordinated regional downscaling experiment (CORDEX-AFRICA) datasets showed a decrease in rainfall (48.64% to 4.6%) and rising temperatures (minimum: 0.58–3.35°C, maximum: 0.5–2.93°C) under RCP 4.5 and 8.5 scenarios. Model calibration and validation were completed using monthly observed streamflow for the most sensitive parameters in the SWAT (Soil and Water Assessment Tool) Calibration of Uncertainty Program. The model performed well between actual and simulated streamflow, with R², NSE, and PBIAS values of 0.84, 0.77, and -15.9 for calibration and 0.88, 0.8, and -14 for validation, respectively. Land-use changes resulted in reduced groundwater (0.81 to 0.7%) and potential evapotranspiration (61.5 to 54.4%), with moderate increases in surface runoff (6.39 to 9.4%), evaporation (23.19 to 27.2%), annual streamflow (3.22% to 23.82%), and water yield (8.1 to 11.7%). Climate change impacts showed higher potential evapotranspiration (23.49 to 29.13%), evaporation (23.69 to 27.35%), surface runoff (10.32 to 15.57%), and water yield (18.62 to 27.67%), but lower groundwater (24.49 to 20.87%) and annual streamflow (38.2% to 23.27%). The combined simulation showed the most significant hydrological shifts, including increased evaporation (2.79 to 17.79%), surface runoff (2.33 to 43.31%), and streamflow, water yield, and groundwater variability. Combined simulations reveal significant changes in water availability, posing long-term challenges for agriculture. Effective land-use planning and climate-resilient water management practices will be vital to risk management.

Soil is the backbone of agricultural productivity and ecological stability; however, soil erosion, intensified by land use and land cover (LULC) alterations and climate variability, poses a critical threat to these resources. This research investigates the impact of LULC dynamics and rainfall change on soil erosion in the Kulfo River Catchment (KRC), Ethiopia, over the past three decades (1987–2022) and under projected 2050 climate scenarios (RCP 4.5 and RCP 8.5). Historical LULC transitions were assessed using supervised Landsat imagery classification (1987, 2003, and 2022) using the Maximum Likelihood Classification (MLC) approach in ERDAS Imagine, and future transitions were forecasted using TerrSet's Multi-Layer Perceptron-Markov chain model. Soil erosion rates were calculated using ArcGIS' Revised Universal Soil Loss Equation (RUSLE), which combined observed and ensemble-projected rainfall data with LULC information. Results indicate that between 1987 and 2022, agricultural land, built-ups, and agroforestry land expanded at the expense of shrubland, forestland, and grazing land, leading to increased mean annual soil loss from 36.2 tons/ha/year in 1987 to 50.7 tons/ha/year in 2022. Projections for 2050 indicate a further rise to 63.2 and 64.1 tons/ha/year under RCP 4.5 and RCP 8.5, respectively. Notably, forest-to-agriculture conversion emerged as a dominant driver of erosion, with soil loss rates escalating from 85 tons/ha/year under historical conditions to 93 and 95 tons/ha/year across scenarios. These findings demonstrate how crucially rainfall intensification and LULC transitions interact to speed up soil deterioration. It is essential to incorporate this knowledge into watershed management to promote evidence-based soil conservation and climate adaptation planning, maintain erosion-resistant land cover, and direct afforestation projects under Ethiopia's Green Legacy program.

A robust assessment of hydroclimatic variability is critical for strengthening drought resilience and optimizing water resource management in climate-sensitive and data-limited regions. This study provides one of the first comprehensive integrated hydroclimatic analyses of the eastern escarpment of the Abaya-Chamo sub-basin, evaluating multi-decadal trends in rainfall, temperature, streamflow, and drought through the Mann-Kendall trend test, Indicators of Hydrologic Alteration (IHA), and drought indices derived using DrinC software. Rainfall trends were largely insignificant across five monitoring stations, except at Hagereselam station, which exhibited an upward trend. Maximum monthly temperatures increased significantly at all stations except Dilla, while minimum temperatures rose at Fisehagenet, Yirgachefe, and Hagereselam. Streamflow analysis at the Tore gauging station revealed elevated low flows, reduced peak flows, slower recession rates, slightly decreased winter discharges, more frequent pulse events, and a reversal in flow direction. Drought assessment using SPI-6 and RDIst-6 indicated increased frequency and severity in recent decades, with Arbaminch, Yirgachefe, Dilla, and Hagereselam being particularly affected. The most severe drought levels were recorded at Yirgachefe (index score −3.31) and Arbaminch (index score −3.27) stations. Short-term indices (SPI-6 and RDIst-6) were more effective than 12-month indices in capturing recurring drought episodes, highlighting the importance of multi-scale drought monitoring. By linking meteorological drought with hydrological regime alterations, this integrated framework provided a comprehensive understanding of drought propagation and hydroclimatic interactions. These findings provide essential guidance for adaptive water governance and region-specific drought mitigation in a region increasingly vulnerable to climate change and broader climate drivers such as El Niño-Southern Oscillation (ENSO), underscoring the urgency of timely interventions in response to ongoing climatic variability.

A robust assessment of hydroclimatic variability is critical for strengthening drought resilience and optimizing water resource management in climate-sensitive and data-limited regions. This study provides one of the first comprehensive integrated hydroclimatic analyses of the eastern escarpment of the Abaya-Chamo sub-basin, evaluating multi-decadal trends in rainfall, temperature, streamflow, and drought through the Mann-Kendall trend test, Indicators of Hydrologic Alteration (IHA), and drought indices derived using DrinC software. Rainfall trends were largely insignificant across five monitoring stations, except at Hagereselam station, which exhibited an upward trend. Maximum monthly temperatures increased significantly at all stations except Dilla, while minimum temperatures rose at Fisehagenet, Yirgachefe, and Hagereselam. Streamflow analysis at the Tore gauging station revealed elevated low flows, reduced peak flows, slower recession rates, slightly decreased winter discharges, more frequent pulse events, and a reversal in flow direction. Drought assessment using SPI-6 and RDIst-6 indicated increased frequency and severity in recent decades, with Arbaminch, Yirgachefe, Dilla, and Hagereselam being particularly affected. The most severe drought levels were recorded at Yirgachefe (index score −3.31) and Arbaminch (index score −3.27) stations. Short-term indices (SPI-6 and RDIst-6) were more effective than 12-month indices in capturing recurring drought episodes, highlighting the importance of multi-scale drought monitoring. By linking meteorological drought with hydrological regime alterations, this integrated framework provided a comprehensive understanding of drought propagation and hydroclimatic interactions. These findings provide essential guidance for adaptive water governance and region-specific drought mitigation in a region increasingly vulnerable to climate change and broader climate drivers such as El Niño-Southern Oscillation (ENSO), underscoring the urgency of timely interventions in response to ongoing climatic variability.

A robust assessment of hydroclimatic variability is critical for strengthening drought resilience and optimizing water resource management in climate-sensitive and data-limited regions. This study provides one of the first comprehensive integrated hydroclimatic analyses of the eastern escarpment of the Abaya-Chamo sub-basin, evaluating multi-decadal trends in rainfall, temperature, streamflow, and drought through the Mann-Kendall trend test, Indicators of Hydrologic Alteration (IHA), and drought indices derived using DrinC software. Rainfall trends were largely insignificant across five monitoring stations, except at Hagereselam station, which exhibited an upward trend. Maximum monthly temperatures increased significantly at all stations except Dilla, while minimum temperatures rose at Fisehagenet, Yirgachefe, and Hagereselam. Streamflow analysis at the Tore gauging station revealed elevated low flows, reduced peak flows, slower recession rates, slightly decreased winter discharges, more frequent pulse events, and a reversal in flow direction. Drought assessment using SPI-6 and RDIst-6 indicated increased frequency and severity in recent decades, with Arbaminch, Yirgachefe, Dilla, and Hagereselam being particularly affected. The most severe drought levels were recorded at Yirgachefe (index score −3.31) and Arbaminch (index score −3.27) stations. Short-term indices (SPI-6 and RDIst-6) were more effective than 12-month indices in capturing recurring drought episodes, highlighting the importance of multi-scale drought monitoring. By linking meteorological drought with hydrological regime alterations, this integrated framework provided a comprehensive understanding of drought propagation and hydroclimatic interactions. These findings provide essential guidance for adaptive water governance and region-specific drought mitigation in a region increasingly vulnerable to climate change and broader climate drivers such as El Niño-Southern Oscillation (ENSO), underscoring the urgency of timely interventions in response to ongoing climatic variability.