Browsing by Author "Hailu, Dereje (PhD)"
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Item Assessing Water Conservation and Demand Management Option for Addis Ababa City(Addis Ababa University, 2010-12) Teklemariam, Mengistu; Hailu, Dereje (PhD)This research develops water demand (end-use) modelling and forecasting, and assesses water conservation and demand management potential for the city of Addis Ababa. The research methodology consists of four steps: 1) data collection, 2) assessing and reducing water distribution system leakage, 3) developing water demand (end-use) modelling and forecasting, 4) water conservation and demand management analysis. International Water Association (IWA)/American Water Work Association (AWWA)’s water loss analysis software and economical leakage reduction model is used for assessing and reducing water distribution system leakage. The Demand Side Management Least Cost Planning Decision Support System or DSS model is developed and used for water demand forecasting and assessing water conservation and demand management measures. DSS model is Microsoft Excel application model. The non-revenue water (NRW) level in the water distribution system in the city of Addis Ababa is found to be 38.2Million m3/year (39.5% system input volume). The real or physical losses are 26.2Million m3/year (27%) of the total NRW, the commercial/ apparent losses are 10.1Million m3/year (10.5%) and unbilled authorized consumptions are1.9 Million m3/year (2%). The economical leakage reduction model result indicated that 5.7Milion m3/year or about 10% of the water losses is an ‘’economical leakage level’. This show about a 29.5% of water losses can be saved through implementation of the recommended water loss reduction programs for the city of Addis Ababa. The water demand (end-use) modeling and forecasting has identified the city average water use in liter per capita per day is 117 and the projected water demand will be 840, 1,502 and 2,735 Million of liter per day by 2020, 2030, and 2040 respectively. With adaption and implementation of the recommended water conservation and demand management program B in the city of Addis Ababa would reduce the future water demand by 66%. This would postpone up to 2020 and downsize of the need for developing new water sources and infrastructures. Furthermore, the benefitcost analysis result of adapting and implementing the recommended water conservation and demand management program B provides present value benefit of 106,550 million birr and costs present value of 862 million birr to Water and Sewerage Authority of Addis Ababa (AAWSA). The benefit-cost ratio is found to be 120. The cost of water saved is found to be 8,145birr/Million litre which is less than the cost of developing new deep wells and operation and maintenance cost of 300,000birr/Million litres by AAWSA. Therefore, water conservation and demand management provides economically feasible and environmentally sustainable solution for meeting the shortfall supply and projected future water demand in the city of Addis Ababa. The environmental sustainability of water conservation and demand management option is reducing the waste water generated from household and buildings to sewerage system or to the environment.Item Assessment of Climate Change Impacts on the Hydrology of Upper Guder Catchment, Upper Blue Nile(Addis Ababa University, 2011-06) Fentaw, Fikru; Hailu, Dereje (PhD)Climate changes alter regional hydrologic conditions and results in a variety of impacts on water resource systems. Such hydrologic changes will affect almost every aspect of human well-being. The goal of this thesis is to assess the impact of climate change on the hydrology of Upper Guder catchment located in Northwest of Ethiopia. The GCM derived scenarios (HadCM3 A2a & B2a SRES emission scenarios) experiments were used for the climate projection. The statistical Downscaling Model (SDSM) was used to generate future possible local meteorological variables in the study area. The down-scaled data were then used as input to the Soil and Water Assessment Tool (SWAT) model to simulate the corresponding future stream flow regime in Upper Guder catchment of the Abbay River Basin. A semi distributed hydrological model, SWAT was developed and Generalized Likelihood Uncertainty Estimation (GLUE) was utilized for uncertainty analysis. GLUE is linked with SWAT in the Calibration and Uncertainty Program known as SWAT-CUP. Three benchmark periods simulated for this study were 2020s, 2050s and 2080s. The time series generated by GCM of HadCM3 A2a and B2a and Statistical Downscaling Model (SDSM) indicate a significant increasing trend in maximum and minimum temperature values and a slight increasing trend in precipitation for both A2a and B2a emission scenarios in both Gedo and Tikur Inch stations for all three bench mark periods. The hydrologic impact analysis made with the downscaled temperature and precipitation time series as input to the hydrological model SWAT suggested for both A2a and B2a emission scenarios. The model output shows that there may be an annual increase in flow volume up to 35% for both emission scenarios in three benchmark periods in the future. All seasons show an increase in flow volume for both A2a and B2a emission scenarios for all time horizons. Potential evapotranspiration in the catchment also will increase annually on average 3 - 15% for the 2020s and 7-25% for the 2050s and 2080s for both A2a and B2a emissions scenarios. Key words: Climate Change; Guder Sub-Basin; GCM; SDSM; SWAT; SWAT-CUP; GLUEItem Dam Breach Modeling and Flood Inundation Mapping For Middle Awash Dam(Addis Ababa University, 2016-11) Tesemma, Kibire; Hailu, Dereje (PhD)Analysis of dam breach events and the associated flooded area are helpful in the risk assessment of dams. Because sudden failure of dam causes risk of flooding hazard to downstream area. The objective of this study is to model the dam break and map flood inundation areas to be used for estimating the potential consequence of dam breach and emergency planning purpose. To meet these objectives materials used are HEC-RAS model in conjunction with HECGEORAS an extension of ARCGIS for the case of Middle Awash Multipurpose Dam which is located in Middle Awash sub-basin and DEM 30m of the area was used because of its availability for the extraction of river geometries in HECGEORAS then exported to HECRAS. In HEC RAS dam feature is entered as inline structure, and breach parameters were estimated using the built-in parameter calculator in HEC-RAS and the PMF flow data is entered and unsteady flow simulation is run. The flood map is done with RASMAPPER in HECRAS and Exported to ARCGIS for further work. Accordingly the Middle Awash dam has been checked for both overtopping and piping mode of failure in HECRAS. The out flow hydrograph result was different for each breach method and breach parameters which in turn affects the inundation area and hazard. It is also different for both mode of failure in HECRAS. The Middle Awash Dam was checked for overtopping failure with the PMF inflow and for piping starting elevation at the center of dam which occur due to internal erosion of dam material. The peak outflow hydrograph was routed down stream and flood inundation mapping was produced. Failure with overtopping inundate 31000ha area and the failure of the dam with piping inundate 30840 ha. The inundation extent, depth and hazard map of dam breach flood shows that the towns at downstream Melkasedi, MelkaWerer and the cultivated area, infrastructures, the animal and human life in the downstream can be affected with inundation caused due to flood from dam failure. The flood inundation map helps in estimation of the severity and extent of dam break flood, warning time, consequence classification for emergency action planning and to alert the government body. Therefore, damages that could occur in the surrounding settlements, agricultural areas, on both lives and infrastructure can be minimized and even controlledItem Flood Mapping and Modeling on Fogera Flood Plain A Case Study of Ribb River(Addis Ababa University, 2011-06) Abera, Zelalem; Hailu, Dereje (PhD)Flood occurs repeatedly in Ethiopia and cause tremendous losses in terms of property and life, particularly in the lowland areas. The majority of flood disasters’ victims are poor people living in nearby stretch of floodplain. Therefore, the study was carried out to perform floodplain analysis and risk assessment of Fogera and nearby areas. This research involves the integration of HEC-Hydrologic Modeling System (HECHMS) and HEC-River Analysis System (HEC-RAS) with Geographic Information Systems (GIS) to develop a regional model for floodplain determination and representation. The study describes the flood extent and depth in the area for different flow conditions derived from the historical flow data of the Ribb River. The hydrologic model is calibrated using HEC-HMS for hourly time series data for return periods of 2, 10, 50 and 100 years. The value derived by the hourly data of the HEC-HMS is compared with different frequency analysis methods. One dimensional hydraulic model HEC-RAS with HEC-GeoRAS interface in co-ordination with ArcGIS was applied for the analysis. Triangulated Irregular Network (TIN) was prepared from shape file generated from spot elevations of the floodplain through field survey data and the DEM of the study area in ArcGIS. Required data sets as stream centerline, banks, flow paths and cross sections were prepared in HEC-GeoRAS thus, creating import file and imported in HEC-RAS. In HEC-RAS, boundary condition for downstream were defined. Similarly, flood discharges for different return periods were also inputted and steady flow analysis was done for the results. The result of hydrologic model by HEC-HMS shows a flow value of 91.8m3/s, 202.4 m3/s, 273.1m3/s, and 308.4m3/s for return periods of 2, 10, 50 and 100 respectively. The result was compared with the frequency analysis using event flow values of the Ribb River. According to the food map, the flooded area for the return periods 2, 10, 50 and 100 years are 12.63km2, 18.63km2, 21.31km2 and 22.5km2 respectively. The classification of flood depth area showed most of the flooding area had water depth less than 1.5m. On the other hand 88% of agricultural land, 11.6% of agro-pastoral land and 1.36% River is inundated by the flood.Key words: HEC-HMS, HEC-RAS, TIN, DEM, flood mapItem General Algebraic Modelling Systems (Gams) A Case Study of Fentale-Qawa Pump Station(Addis Ababa University, 2015-03) Girma, Etana; Hailu, Dereje (PhD)Traditionally, design engineers tend to be conservative in calculating pump station decision variables by focusing on peak demands that occur about1% of the time. On the other hand, optimal design and operation of pumping stations are mathematically large-scale non-linear problems. Consequently, there is a possibility of using an optimum operation schedule on a set of non-optimum pump combinations that are selected narrowly based on peak discharge of system demand. Thus, optimization model is developed in this thesis work to tackle optimization problems in pump stations. Optimal design and operation of irrigation pump station system is carried out with a help of a computer model developed in a General Algebraic Modeling Systems (GAMS). The model makes use of the latest advances in optimization techniques that utilize in-built solvers in GAMS to solve optimization problems with lots of decision variables and constraints. It is based upon one major objective function to find optimized solutions of equations. Automatically generated model outputs include selected pump type, capacity, number of pumps and optimum schedule of pump operation for problems involving design phase. For existing pump stations, it simply generates a preliminary optimum operation schedule. The developed optimization model was tested on previously optimized problem by different researchers and then implemented on a case study, Fentale-Qawa Pump Station, to optimize the annualized investment cost of the pumping station and its annual operating cost. GAMS results were presented and compared with five other well-known optimization techniques. The results were unique and stood second to Lagrange multipliers (LM) method in minimizing Annual Total Cost (ATC) of the sample problem. Implementation of the model would have saved 35% of Initial Investment Cost in pumps had it been used during design phase. The savings occurred in the annual operation cost is 11% compared to the optimized operation cost of the existing pump station. It is clear that the developed optimization model provides the designer and the operator with optimized combination of design variables and operation parameters. (Key words: GAMS, Optimum design variables, Optimum operation schedule, Pump)Item Hydrological Trend, Variability and Time Series Modeling of Weyib Catc(Addis Ababa University, 2017-08) Legesse, Abel; Hailu, Dereje (PhD)The main goal of this study is to assess trend, spatio- temporal variability of rainfall and runoff, and time series modeling of major tributaries of Weyib River catchment, which is located in Genale Dawa basin between 6022’ to 7006’N and 39037’ to 41015’E. Stream flow records from six flow-gauging stations in four major river catchment of the weyib between (1981- 2008) and six precipitation stations all over the weyib catchment between (1984-2014) were studied at monthly, seasonal, and annual scales. In the study, the data were firstly subjected to quality checks through the cumulative deviations test and the standard normal homogeneity test. To detect correlation Lag-1 autocorrelation coefficient was used. ArcGIS 10 environment is used to investigate the spatial variability. The Coefficient of Variation (CV) was used for variability analysis. Mann-Kendall trend analysis and Sen’s slope estimator in MAKESENSE version 1.0 Excel template are used in determining the changes in the rainfall and runoff. ARIMA model in Minitab 17 Statistical software was used for time series modeling. By using statistical measure (R2, AIC and BIC) it was determined that, ARIMA time series model is better appropriate to stream flow forecasting. The interesting observation is that all sub catchment of the Weyib catchment for both rainfall and runoff exhibit different behavior as far as trend and variability analysis is concerned. Trend analyses with Mann-Kendall test show that, there is increase in significant trend in annual mean runoff at Togona and Tebel station while the other four stations (Shaya, Agarfa, Alemkerem and Denbel) shows no significant trend. From precipitation stations, only Ginir station shows significant increasing trend in annual basis. The direction of rainfall and runoff trend was, in general, upward and statistically significant (upward) trends (95% to 99.9%) significant levels were observed. Global climate change influence on the changes in rainfall and runoff characteristics was not conclusive. The key conclusion is that, the results of this study are expected to assist water resources managers and policy makers in making better planning decisions in the Weyib River catchment. Keywords: Weyib River catchment ; Minitab 17 ;Trend analysis ;Precipitation ; Mann-Kendall Test ; Sen’s Slope Estimator; probability distributionItem Optimal Design and Scheduling of Irrigation Pumps by Using General Algebraic Modelling Systems (Gams) A Case Study of Fentale-Qawa Pump Station(Addis Ababa University, 2015-03) Etana, Girma; Hailu, Dereje (PhD)Traditionally, design engineers tend to be conservative in calculating pump station decision variables by focusing on peak demands that occur about1% of the time. On the other hand, optimal design and operation of pumping stations are mathematically large-scale non-linear problems. Consequently, there is a possibility of using an optimum operation schedule on a set of non-optimum pump combinations that are selected narrowly based on peak discharge of system demand. Thus, optimization model is developed in this thesis work to tackle optimization problems in pump stations. Optimal design and operation of irrigation pump station system is carried out with a help of a computer model developed in a General Algebraic Modeling Systems (GAMS). The model makes use of the latest advances in optimization techniques that utilize in-built solvers in GAMS to solve optimization problems with lots of decision variables and constraints. It is based upon one major objective function to find optimized solutions of equations. Automatically generated model outputs include selected pump type, capacity, number of pumps and optimum schedule of pump operation for problems involving design phase. For existing pump stations, it simply generates a preliminary optimum operation schedule. The developed optimization model was tested on previously optimized problem by different researchers and then implemented on a case study, Fentale-Qawa Pump Station, to optimize the annualized investment cost of the pumping station and its annual operating cost. GAMS results were presented and compared with five other well-known optimization techniques. The results were unique and stood second to Lagrange multipliers (LM) method in minimizing Annual Total Cost (ATC) of the sample problem. Implementation of the model would have saved 35% of Initial Investment Cost in pumps had it been used during design phase. The savings occurred in the annual operation cost is 11% compared to the optimized operation cost of the existing pump station. It is clear that the developed optimization model provides the designer and the operator with optimized combination of design variables and operation parameters. (Key words: GAMS, Optimum design variables, Optimum operation schedule, Pump)Item Performance Comparison of Conceptual Rainfall-Runoff Models on Muger Catchment (Abbay River Basin)(Addis Ababa University, 2011-01) Tufa, Kumela; Hailu, Dereje (PhD)The research is aimed at conducting catchment modeling for better understanding of hydrologic functioning and runoff generation mechanisms of the Muger catchment and selecting the best conceptual rainfall-runoff model that can be used in the design, planning, and management of water resources in Muger sub catchment (Abbay River basin. The conceptual rainfall runoff models chosen for this study are SMAR and HBV-light (Beta Version). Each of the models was applied to test the catchment, using split record evaluation, involving the calibration and verification periods (about 60% for calibration and 40% for verification). During calibration period of each model, the optimized parameters which give good performance result were determined (Reff=0.7) for both models. These optimized parameters are validated. Performance of the model in the validation period indicates that the efficiency is better than calibration period for both models. For the models SMAR and HBV the obtained Reff during validation is 0.70 and 0.71 respectively. Qualitative analysis of models shows that both models have poor performance in producing extreme flows such as floods and low flows. Model parameter transferability test was conducted on the daily time step models showed less performance in Aleltu catchment; whereas the monthly time step model showed high Reff values for both models. The discrepancy occurred between simulated and observed runoff may be due to in adequacy of model structure, human intervention, incorrect estimation of parameters especially in case of manual optimization , if there is an interflow between catchments, the quality of data and the absence of any substantial, consistent , or coherent relationship in the data used to calibrate the models. Key words: Muger; HBV; SMAR; Rainfall-RunoffItem Prediction and Flood Modeling For Kello Town(Addis Ababa University, 2017-03) Bereded, Admasu; Hailu, Dereje (PhD)Nowadays, extraordinary floods are common to many parts of Ethiopia causing a lot of losses to human lives as well as damage to property. Though, Kello town is been one among such places that has affected by flash flooding from rainfall, in particular of the ungauged Kello River which passes through the center of the town. This thesis is aimed to identify flood causative factors, peak flood estimation, delineate flood risk areas that can be affected by extraordinary floods and to recommend mitigation measures. This is accomplished by adopting application software's like Arc View GIS, HEC-HMS and HEC-RAS and related software’s. The data usage for this thesis is (DEM and contour), (soil, land use and 1:50,000 scale topo map) and text (rainfall and discharge) type. For precipitation modeling, ERA Intensity-frequency-duration curve is used for frequency storm. For geographic and terrain data, 30m resolution DEM for catchment, 4m contour interval for the town part and Kello Stream cross section are used. In this thesis, the flood magnitude is estimated for 2, 5, 10, 25, 50 and 100years return period peak flood discharge using Computer Programs HECGeo-HMS and HEC-HMS. And the corresponding results are estimated as 38.05, 47.38, 67.28, 81.87, 92.66 and 103.33m3/sec. 50 and 100years peak discharge is used for further analysis which is flood mapping. Based on the result full of the town, the right and left side of the cultivated land and left and right sides of Kello Stream are found to be the vulnerable areas. According to the flood delineation an area of 92.7 and 95.5ha of land will be inundated by 50 and 100 year and this flood has an inundation depth of 4.7806m at the downstream of the catchment and decreases to the upstream of the catchment. Besides this mitigation measures considering different alternative measures levee construction is found to be best fitted for the study area along the selected reach of the Kello stream and Kello Town and the agricultural area.Item Surface Irrigation Suitability Analysis of Southern Abbay Basin by Implementing Gis Techniques (A Case Study in Dedessa Sub-Basin)(Addis Ababa University, 2017-02) Tariku, Meron; Hailu, Dereje (PhD)The study aims at evaluating physical suitability (land and water resource) for surface irrigation development using GIS techniques. The Dedessa sub-basin was selected as a case study for this thesis work. The Dedessa sub-basin located at the Southern part of the Abbay River Basin. The study area covers an area of about 1.96 M hectares. The evaluation of land in terms of the suitability classes for surface irrigation was based on the method as described in FAO guideline for land evaluation. The essence of land evaluation is to compare or match the requirement of each potential land use with the characteristics of each kind of land. (FAO, Land Evaluation for Development. Soil bulletin) A land unit is obtained by the overlaying of selected theme layers, which has unique information of land qualities for which the suitability is based on. The selected theme layers for this study include soil types, with their corresponding physical and chemical characteristics that affect irrigation agriculture, land cover, and slope layer, which is derived from the Digital Elevation Model of the study area. As its being the most limiting factor for the realization of, especially for surface irrigation method, the slope layer was used as the base map for the overlaying analysis. The suitable land identified categorized according to the different climatic zones along the Dedessa River in the sub-basin. They are mostly concentrated in the central and Eastern part of the sub-basin along the Dedessa and Wama River valleys. The 95, 90, 85, and 80 percentage time exceedence flow of the available surface water in the respective climatic zones was estimated and the area that can be irrigated with this flow was computed using the selected climatic station data and estimated ETo.Item Urbanization and Its Effect on Surface Runoff (A Case Study on Great Akaki River, Addis Ababa, Ethiopia(Addis Ababa University, 2016-06) Nega, Misganaw; Hailu, Dereje (PhD)On this study the effect of high urbanization rate of Addis Ababa City in general the study area on the Great Akaki River is assessed. The surface runoff generated from the catchment is estimated based on the rainfall intensity and major characteristics of the catchment area which are the major factors for designing urban storm water drainage facilities and structures. Satellite image for 1989, 2000 and 2010 of the catchment area is taken based on the quality of data and the available resolution. ArcGIS and GIS extension tools are used to extract hydrological characteristics of the catchment; HEC-RAS for hydraulic modeling, and HEC – HEC-HMS to simulate rainfall - runoff process on Great Akaki watershed which is the major watershed located at the center of Addis Ababa. The hydrological and hydraulic modelings are accomplished by dividing the watershed in to different sub-catchments. To compute infiltration loss SCS CN method; converting excess rainfall to runoff model SCS unit hydrograph, and channel flow routing accomplished by using Muskingum routing method of HEC-HMS model. To evaluate the accuracy of the simulation model calibration and validation was conducted. The hydrological modeling classified in to two: the first simulation shows the effect of high urbanization growth on the basin. Accordingly, the peak discharge for 1989, 2000 and 2010 at the Bridge outlet along Addis Ababa Bishoftu Road is 131, 153.4 and 188.1m3/s respectively. To avoid the effect of rain fall variation on the generated peak discharge similar hourly rainfall of 18 July 2010 was used for each respective year. The second simulation uses frequency storm method for 10, 50 and 100 return periods and peak discharge of 403.80, 546.50 and 634.70m3/s for each respective return period was obtained. The result found from HEC-HMS frequency storm method used for hydraulic analysis and flood map hazard generation. Flood inundation maps produced using ArcGIS to visualize flood depth and extent for each return period. Accordingly, maximum flood depth of 7.86, 9.07 and 9.82m for 10, 50, and 100 year return periods respectively was found with flood extent of 82.34 for 10 return period and 100.15 for both 50 and 100 year return periods at the middle of the final reach of the study area. Keywords: DEM, TIN, flood modeling; HEC-HMS/RAS; HEC- GeoHMS/RASItem Validation of Global Precipitation Data Sets to Runoff Generation Using Swat Modeling System(Addis Ababa University, 2015-12) Tadese, Fenet; Hailu, Dereje (PhD)The main objective of this study is to evaluate the performance of globally gridded high – resolution satellite rainfall products (TMPA 3B42V7, Corrected coarse CMORPH, and Adj-PERSIANN) under sparse ground based data and complex topography of Angar Watershed (3627.6 km2) in Upper Nile basin Ethiopia through semi-distributed hydrological model SWAT for monthly streamflow simulation. The model is calibrated for the period of 2003 – 2007 and validated for the period of 2008 – 2010. Comparisons of the simulations to the observed streamflow at the outlet of Angar Watershed form the basis for the conclusions of this study. The Nash-Sutcliffe Efficiency (NSE), Coefficient of Determination (R2), Root Mean Square Error (RMSE), linear correlation coefficient (R) and BIAS indices were used to benchmark the model performance. Our results reveal that the performance of the satellite rainfall products as input to SWAT for monthly stream flow simulation strongly depends on the product type. Simulation from all rainfall inputs captured the trend of observed hydrograph. Simulation based on the new version of TMPA 3B42V7 and CMORPH showed consistent and modest skills in their simulations but slightly overestimates the large flood peaks in some years (2005 & 2006). On the other hand, the infrared – based algorithm PERSIANN simulation showed poor skills in reproducing the hydrograph at the outlet of the watershed. One of the reasons may be due to PERSIANN product is relatively less correlated to observed rainfall and other satellite products. Overall, the results indicate that although some uncertainties exist in these gridded datasets (3B42V7 & CMORPH), the application of these gridded data prove useful for hydrological studies in the absence of station data. It strongly indicates the growing potential of the predictive accuracy of the satellite rainfall products in reproducing hydrological features. Key words: Satellite rainfall products, SWAT model, Angar watershedItem Water Use and Operation Analysis of Water Resource Systems in Omo Gibe River Basin(Addis Ababa University, 2011-05) Asefa, Daniel; Hailu, Dereje (PhD)In this study, HEC-ResSim (Hydrologic Engineering Center-Reservoir System Simulation) model was used to simulate water use and operation of existing, ongoing and planned hydraulic infrastructures, and irrigation schemes in Omo Gibe river basin. For these purpose five different water resource scenarios were simulated viz. Scenario-T, Scenario-A, Scenario-B, Scenario-C and Scenario-D. Scenario-T was first set up to simulate gauged flow routing without taking into account effects of development and a good agreement was observed between simulated and measured flow at Karadus station. The Nash-Sutcliffe efficiency criterion obtained for the catchment was 0.782. Following this, the model was configured to simulate the recent and proposed development interventions on water resource. Scenario-A result showed that an average annual energy of 780GWh/year and 1911GWh/year are produced by Gibe I and Gibe II respectively when they are operated in tandem. Equivalent storage distribution was also examined among reservoirs in the entire simulation period. The current study, HEC-ResSim simulation in scenario B, has discovered that long term effects of operation of Gibe III power plant would increase the dry season outflow and decrease in flood season outflow from the Omo- Gibe river system. An average increase of 130% in mean monthly inflows from November to June and decrease of 25% in mean monthly inflows from July to October was observed at Karadus. But the mean annual outflow from the basin at Karadus will be decrease by 1.14%. Simulation of Gibe III power plant produced an average annual energy of 6,488GWh/year and power of 758.94MW.The firm energy and power that can be guaranteed 90% of the time are 5885GWh/year, 625.0MW respectively. The average energy obtained is close with the study made by EEPCO. The firm energy obtained is also similar and greater than the energy obtained during reservoir operation studied by EEPCO. Due to upstream regulation i.e. intervention the proposed power plants, Gojeb and Hallele Warabesa stage I and II, in the upstream Omo-Gibe basin under scenario D can increases firm energy production of Gibe III power plant to 6023GWh (2.75%) per year with same reliability and the average annual energy can also increase to 7587 GWh per year (by 15.66%). Moreover, during scenario D simulation annually about 1.87BCM volume of water will be diverted into irrigation site under full irrigation development (142,000ha) and the annual volume of water from Omo-Gibe river system below the proposed irrigation sits will decrease by 14.15%. Keywords: Firm Energy, HEC-ResSIM, Reservoir Operation, Simulation scenario, Karadus, and Reservoir Network IV Dedication This work is dedicated solely to my mother Abeba Yemataw,