PhD Theses (Civil Engineering)

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Browsing PhD Theses (Civil Engineering) by Author "Ayalew, Lewoye Tsegaye"

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    Impact Assessment on Watershed Hydrology and Soil Erosion under Land Use Land Cover and Climate Change Scenarios in Rib and Gumara Watersheds, Ethiopia
    (2021) Ayalew, Lewoye Tsegaye
    Currently, watersheds are the focus of environmental conservation for sustainable development. Watershed-scale hydrology and soil erosion are the main environmental components that are greatly affected by climate and environmental perturbations. The aim of this study is to assess the impacts of Land Use and Land Cover (LULC) and climate changes on hydrology and sediment at the watershed-scale and to understand the relationships between hydrologic components and sediment yield with climate and land-use scenarios. An approach of modelling was used to examine the impacts of LULC and climate change scenarios on hydrology and sediment. The empirical LULC change model, Dynamic Conversion of Land Use and its Effects (Dyna-CLUE), and a hydrologic model, Soil and Water Assessment Tool (SWAT) were employed to assess the impacts of LULC and climate changes on soil erosion and sedimentation in the Rib and Gumara watersheds, North-western Highlands of Ethiopia. The Dyna-CLUE model was calibrated with 1984 LULC map and validated with the simulated and reality LULC maps of 2016 to predict the LULC until 2049. The regional climate model (RCM) REMO and RACMO22T model outputs were analysed to assess climate changes. The REMO is from the driving model of ECHAM5 based on the IPCC SRES-AR4 A1B emission scenario. The RACMO22T model is from the driving model of the Hadley Global Environment Model 2-Earth System (HadGEM2-ES) in CORDEX-Africa under emission scenarios of RCP2.6, RCP4.5, and RCP8.5. These climate models were bias-corrected and the future climate of 2025-