Institute of Technology

Permanent URI for this communityhttps://etd.hu.edu.et/handle/123456789/66

The Institute of Technology focuses on education, research, and innovation in engineering, technology, and applied sciences to support sustainable development.

Browse

Filters

2019 - 201912020 - 20231

Settings

Subject: search.filters.subject.Inundation Mapping

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    DAM BREACH ANALYSIS AND FLOOD INUNDATION MAPPING FOR GIDABO DAM
    (Hawassa University, 2019-03-15) FIRAOL BEFEKADU GELETA
    This study presented the dam breach analysis and flood inundation mapping for Gidabo rock-fill embankment dam found in Southern part of Ethiopia. The geometrical data used for this study was extracted from the recently released ALOS PLASAR digital elevation model by Alaska Satellite Facility, which is having the spatial resolution of 12.5 by 12.5 meters. One dimensional unsteady flow simulation within HEC-RAS model was used to simulate dam breaching for both overtopping and piping failure scenarios. Dam breach parameters estimation was done for different empirical equations. Froehlich (2008) and Von Thun & Gillete methods was preferred since the results obtained for these methods are more approaches to the envelope curve developed for the historical dam failures for overtopping and piping failures, respectively. RAS mapper and ArcGIS tools was used to present the maps of spatial distribution of flood extent, flood depth and flood velocity, flood inundation, flood hazard maps of the study area. The breach parameters estimated for both overtopping and piping failure scenarios was provided the reasonable values. The maximum breach discharge simulated for overtopping and piping failure was obtained as 15,945.18 m3 /s and 14,904.18 m3 /s, respectively. Since the failure were tested for hydrologic failure and for normal water level condition, the magnitude of flood and the spatial distributions are obviously different. Developed inundation maps from this study could be possibly help as guidance for dam owners to develop the emergency action plan and for future expansion of irrigation project infrastructures, and other developmental activities around the downstream of the dam
  • No Thumbnail Available
    Item
    ANALYSIS OF DAM BREACH PARAMETERS AND INUNDATION MAPPING (THE CASE OF KALID-DIJO EMBANCKMENT DAM)
    (Hawassa University, 2023-07-08) Lemeneh Mersha
    Embankment dam risk assessment is a method used to evaluate the catastrophic impact of dam break flooding. This study was conducted to analyze dam breach parameters of Kalid Dijo dam and inundation mapping. The dam breaching outflow hydrographs, inundation mapping and downstream flood propagations were simulated by applying HEC-RAS 5.0.6 model to study the possible relationships among the peak flows, dam breach parameters, and map the inundation area. The initial parameters are taken from literature based on the dam type and its silent features. HEC-RAS model 2D reservoir and river routing were performed and resulted in multiple breaching outflow hydrographs for specified conditions at the dam site and at specified downstream reach stations. The maximum breach discharge resulted from the model was 852.18 m3 /sec which results in overtopping the dam by 0.6m. Four Time to Failure Hour and four Breach Side Slope values are used for the sensitivity analysis at the dam site. Accordingly, the change of Time to Failure Hour resulted 403% change of the maximum discharge at the dam site which is high compared to the change in Breach Side Slope which produced 100% reduction in maximum discharge. This implied that the peak discharge was highly sensitive to changes in Time to Failure Hour more than five times than Breach Side Slope; and Time to Failure Hour is a controlling parameter at the dam site. At two randomly selected downstream observation stations 01 and 02, an increase in TFH and increase in Manning coefficient resulted in decrease in peak flow at reach station-01 and 02. The total inundated area is 454.19 sq.km. It covers 1100ha of command area and some parts of Dalocha town.