Hydropower Engineering

Permanent URI for this collection

http://etd.aau.edu.et/handle/123456789/215

Browse

Browsing Hydropower Engineering by Author "Yilma Sileshi (PhD)"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Grand Ethiopian Renaissance Dam Reservoir Operation Simulation using HEC-ResSim and its impact on downstream Hydropower Generation
    (Addis Ababa University, 2014-03) Zelalem Tesfaye; Yilma Sileshi (PhD)
    In this study, HEC-ResSim model was used to simulate operation of existing hydraulic infrastructure, and major irrigation schemes in the Eastern Nile river basin and the new hydraulic infrastructure (GERDP).The main objective of this research is to find out the extents of the impact to which the introduction of new upstream reservoir, GERDP, on downstream users of the Nile waters by using the HEC-ResSim reservoir simulation model. Repeated runs of the HEC-ResSim model were made using different filling and after filling of GERDP scenarios to compare the effect of GERDP under alternative operating policies. The computational algorithm in HEC-ResSim is divided in to three major components: (1) watershed setup, (2) reservoir network, and (3) simulation for Calibration, Baseline and Alternative (Dry, Wet and Average filling and after filling) phase scenarios. The methodology computes the required releases to limit storage to the capacity available based on the probabilistic properties of future flows, conditional to current stream flow conditions. The first setup was to simulate gaged flow routing without taking into account effects of development using the flow data of 1956 to 2003 and a good agreement was observed between simulated and gaged data at El-Deim, Khartoum, Dongola, Hassanab and Tamaniat stations. The correlation coefficient R2 values for those stations were found to be in good agreement and found to be more than 0.925 for each station. Following this, the model was configured to simulate the existing and proposed development intervention. The baseline development Scenario is considering only existing major water infrastructures (i.e. reservoirs) and major irrigation schemes in Sudan and Egypt for a period of 1956 to 2003. The simulation result showed that an average annual energy of 14,810.83GWh/year is produced by Roseires, Sennar, Merowe and HAD. The Alternative scenario development which includes during filling and after filling of GERDP, HEC-ResSim simulation, has discovered that long term effects of new upstream reservoir on the operation of downstream reservoirs. After filling of GERDP phase scenario simulation using flow data of 1956 to 2003, the simulation result showed that an average annual energy of 31,363.63GWh/year will be produced by GERD, Roseries, Sennar, Merowe, and HAD (111.76% increase than without GERD), the reduction of average annual energy by 395.41 GWh/year from HAD will be compensated by the energy produced by GERDP and Sudan power plants, which will increase the total energy produced by the whole Eastern Nile system. During the filling phase scenario simulation results showed that an average annual energy of 27,041.96 GWh/year, 25,695.48 GWh/year, and 31,213.61 GWh/year will be produced by the 5 power plants during Average, Dry and Wet filling Scenarios respectively and average annual energy production from GERDP will be 11,314.38, 8,974.19, and 11,925.61GWh/year for the respective sequence of filling years. An average monthly power of 1,625.46MW and average annual energy of 14,238.99GWh/year will be produced during normal operation of GERDP (i.e. after filling from 2019-2066 for 48 years). Due to upstream regulation (i.e. intervention of GERDP, in the upstream of the Eastern Nile river basin) there will be an increase in average monthly inflow downstream in the driest month of the year and the annual average reservoir pool level increase which result in increase of power head.
  • No Thumbnail Available
    Item
    Hydraulic Modeling and Flood Mapping Of Fogera Flood Plain: A Case Study of Gumera River
    (Addis Ababa University, 2012-03) Brhane Hagos; Yilma Sileshi (PhD)
    Nowadays, extraordinary floods are common many parts of Ethiopia causing a lot of losses to human lives as well as damage to property. Historically, Fogera/Dera flood plain has been vulnerable to flash flooding from rainfall, in particular of the Gumera catchment which passes in between the Fogera -Dera weredas. The tributary rivers are originating from the southern highlands of Debretabor with a steep slope. The Fogera –Dera flood plain is located east of Lake Tana in North West Ethiopia about 625 km from the capital city Addis Ababa and the terrain is fairly flat. The Gumara catchment drained by Gumara River is part of Nile basin The over flow of the river affects part of the Fogera /Dera flood plain but mainly the Fogera part at lower reach near to Lake Tana. Hence, this thesis is to identify peak flood and delineate and produce flood inundation mapping areas that can be affected by extraordinary floods and to recommend mitigation measures. This thesis tries to consider more options and fills the gaps not covered by others, adopting more than seven application soft wares like Arc GIS, Global Mapper, HEC-HMS, HEC-DSS, HEC-GeoHMS, HEC-RAS and HEC-GeoRAS. 30m*30m resolution DEM for the catchment and 2m contour interval for Fogera flood plain are used to analyze terrain information. For precipitation modeling, the daily rain fall basis is used for HEC_HMS calibration and ERA Intensity-frequency-duration curve is used for frequency storm analysis. The hydrologic frequency model is used for determining the peak flow discharge for return periods of 2, 5, 10, 50 and 100 years and the result is found to be 197.7m3/s, 246.8 m3/s, 265.4m3/s, and 306.0m3/s and 319.60m3/s respectively. For the 100 year flood frequency the maximum depth of flood is 7.94m and this depth of flood is extended to the flood plain up to 10km of the flood area which affects mainly the Wageta, Kidist Hana, Shina, Quhar Michael and Bebeks Tana mistily and Jigna Weredas .The total area affected by this flood is31.36 km2 and the area affected by the 2year flood inundation of 7.36m is 22.27 Km2.