Hydraulic Engineering

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Browsing Hydraulic Engineering by Subject "Abstraction"

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    Surface Water Potential Assessment And Demand Sceinario Analysis In Omo Gibe River Basin
    (Addis Ababa University, 2015-07) Atinafu, Dereje; Nigusse, Agizew(PhD)
    A study was conducted in Omo Gibe river basin surface water potential and demands using hydrological model SWAT and a program WEAP. A detail review of current water resources potential, current demand and future demand up to 2030 were properly estimated. Earlier, different commissions, agencies, researchers have estimated water resources of the country using different approaches. All these studies are based on the observed flows at terminal sites and upstream abstractions for irrigation and domestic consumptions. Limitations of these studies are: limited field data on abstraction, lumped approach in estimation at terminal sites of the basin no mechanism for cross validation and new large scale irrigation projects are not considered. This study emphasizes on quantifying basin scale water wealth by transformation from presently adapted basin terminal gauge site runoff aggregation to meteorological based water budgeting exercise through hydrological modeling approach Integrating satellite image, geographical information tools, hydro-meteorological data and hydrological models. Daily rainfall data, daily temperature data were obtained for the last 20-30 years from the Ethiopian national metrological Department. Land use grids 90m resolution were used. Soil textural map, land use map, digital elevation map, and command area map were integrated to compute hydrological response grid of the basin. In this study Observed discharges at various gauge stations were obtained from Ministry of irrigation water and energy and model was thoroughly calibrated and validated. It is found that computed runoff is very well matching with the filed observed data with good accuracy. Missed hydro-metrological data was filed using appropriate method and the performance of the method also cheeked. Soil and Water Assessment Tool SWAT integrated with GIS were used to model the watersheds and to simulate runoff. Water Evaluation and Planning (WEAP) estimates the current and future water demands for irrigation, domestic, industrial/commercial, and livestock demands. The results were compared and sensitivity analyses were computed for SWAT. ESCO and CN are the most sensitive parameters. The model calibrated for period of 1990-2002 and land use data of 2002 were used. Finally the model also validated for period of 2002-2010. Hydrograph characteristics of observed and simulated events are compared using different evaluation criteria consisting of Nash-Sutcliffe coefficient of efficiency (EF) and R-Squared, r-squared is another statistical measure of how well a regression line approximates real data points. Addis Ababa university institute of technology wants to generate up-to-date information‟s on water and land resources management and development in Omo basin, and this study aims to provide water demands overview. Current water demand and future prediction in demand are estimated by considering different demand scenarios. Environmental flow, current irrigation potential, improvement in irrigation network efficiency, and irrigation projections are key Scenarios used in this study. Scenarios impacts on water demand are assessed based on the impacts on indicators; elaboration on Scenarios is based on the assumptions made, drivers to be changed and indicators to be analyzed. The indicator analyzed in this study is unmet demand. Irrigation schedule, Irrigation efficiency improvement, water requirement, population growth, inflows to the sub catchment, priority of demand i.e. irrigation, domestic, commercials and industrial, Land use area, crop type and varieties are drivers to be changed in each scenarios.