Soil and Water Conservation Engineering
Permanent URI for this collectionhttps://etd.hu.edu.et/handle/123456789/67
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Item ESTIMATION OF SEDIMENT YIELD AND EFFECTIVENESS OF LEVEL STONE BUNDS TO REDUCE SEDIMENT LOSS: IN GUMARA-MAKSEGNIT WATERSHED, NILE BASIN, ETHIOPIA(Hawassa University, 2018-10-21) ATIKILT ABERA ALEMAYEHUThe study was conducted in Gumara-Maksegnit watershed and it’s sub-catchments to estimate event-based sediment yield and to evaluate the effectiveness of level stone bunds based on sediment loss reduction. Modified Universal Soil Loss Equation (MUSLE) was used for estimation of sediment yield. The model input parameters were collected from different sources and these are discretized and preprocessed with the help of various suitable software and tools. Finally, all six model factors were combined together using the raster calculator in map algebra to estimate the sediment yields of the study watersheds. The event-based mean observed and model estimated sediment yields were (0.5581, 0.4031 ton ha-1 ) for Gumara-Maksegnit watershed, (0.5125, 0.4194 ton ha-1 ) for treated sub-catchment and (1.0694, 1.0150 ton ha-1 ) for untreated sub-catchments respectively. The sediment losses between treated and untreated sub-catchments were highly significantly different when the sediment loss reduced by 58.8% as a result of level stone bund interventions. However, the observed and estimated sediment losses are not significantly different within a watershed. Hence, the model was well performed to estimate sediment yield in the study area with R2 (0.62, 0.72 and 0.7) and NSE (0.53, 0.71 and 0.34) for treated, untreated and Gumara-Maksegnit watershed respectively. Hence, the result showed that the Modified Universal Soil Loss Equation (MUSLE) model was well suited for reliable applications of sediment yield estimation in the study area as well as similar agroecologiesItem HYDRO-SEDIMENT RESPONSES TO MANAGEMENT OPTIONS UNDER CURRENT AND FUTURE CLIMATE CHANGE SCENARIOS IN MAYBAR SUB WATERSHED, SOUTH WOLLO ZONE, ETHIOPIA(Hawassa University, 2022-10-22) MULUKEN LEBAY EGIGUClimate change coupled with inappropriate land use management is a serious environmental challenge in the highland part of Ethiopia. The aim of this study was to investigate hydro-sediment responses to management options under current and future climate change scenarios in Maybar watershed, Northern Ethiopia. We employed soil and water assessment tool (SWAT) for hydrologic modeling and CORDEX-climate data under RCP 4.5 and RCP 8.5 emission scenarios was used for climate projections. Soil map was prepared by digitizing soil characterization map of the watershed generated by Weigel in 1986. DEM data with 2m spatial resolution was obtained from water and land resource center and land use classification was done through digitization of google earth images. Better agreement between calibrated SWAT simulation and observed variables was achieved. Delta change bias correction method was empolyed to improve the climate simulation in reproducing the observed climate variables. We found a considerable increase in annual precipitation by 18.71% and 22.33% for RCP 4.5 and RCP 8.5, respectively compared with the current climate conditions. Climate change induced hydro-sediment results were observed to be consistent with predicted precipitation. Under the current climatatic conditions, average sediment yield at the subbasin scale varies from negligible (under terrace complementation) to approximately more than 50 t ha-1 yr-1 with a basin average of 32 t ha-1 yr-1 (under no-terrace conditions). The implementation of management alternatives gets the dry seasons hydrological behavior of the catchment improved and climate change induced sediment yield reduction. Generally, the information could possibly support decision makers and planners to implement best-fitted management options and thereby reduce current and expected aggressive sediment loss situations.