Dam Break Analysis and Inundation Mapping, Case Study of Fincha’a Dam in Horro Guduru Wollega Zone, Oromia Region, Ethiopia
Jiregna Nugusa Duressa,
Asie Kemal Jubir
Issue:
Volume 6, Issue 2, April 2018
Pages:
29-38
Received:
23 October 2017
Accepted:
18 December 2017
Published:
26 April 2018
Abstract: Fincha’a Dam was constructed in 1973 for the purpose of electricity generation, irrigation, fishery and truism with 22.2m height and 340m crest length. Fincha’a dam is rock fill dam with uncontrolled over flow spillway. There are different economic developments downstream of the Fincha’a dam including hydropower pant, irrigation project, residential house and sugar factory. These economic developments are affected either dam break by overtopping or piping mode of failure. The calculated breach parameters by Von Thun and Gillette Regression equation are selected as input data into the HEC-RAS model for dam break analysis. The general objective of the study is to analyze Dam break by using hydraulic models (Hydraulic Engineering Center’s River Analysis system). For this study the failure location is assumed to be at the center of the dam due to presence of high hydrostatic pressure and develop equally in both sides. From the result of Fincha’a dam break simulation the peak discharge formed by overtopping mode of failure is more devastating than the piping mode of failure. The effect of dam breach parameters on discharge is more pronounced than that of the water level. Dam break has greater impact on the downstream location where is closer to the dam in accordance with the hydrograph at downstream locations. The created Fincha’a river network was exported to HEC-RAS model for further dam break analysis by addition of different geometric data including dam information, calculated breach parameters, initial condition, upstream and downstream unsteady boundary condition. After full computation the model result were exported to integrated Arc-GIS and HEC- GeoRAS model for mapping flood inundation. Developed inundation map guides the dam owners and emergency management authority to give emergency action plan for the highly affected area by flooding and used for planning future economic development activities.
Abstract: Fincha’a Dam was constructed in 1973 for the purpose of electricity generation, irrigation, fishery and truism with 22.2m height and 340m crest length. Fincha’a dam is rock fill dam with uncontrolled over flow spillway. There are different economic developments downstream of the Fincha’a dam including hydropower pant, irrigation project, residentia...
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