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| dc.contributor.author | FANA, DEJENE | |
| dc.date.accessioned | 2020-03-19T08:38:53Z | |
| dc.date.available | 2020-03-19T08:38:53Z | |
| dc.date.issued | 2020-03-19 | |
| dc.identifier.uri | http://hdl.handle.net/123456789/10703 | |
| dc.description.abstract | Flood devastate millions of people around the globe each year. Nowadays the major environmental disasters in Ethiopia are recurrent droughts and floods. Flood occurs repeatedly in Kalo and Bishe kebele,Dewa Chefa, Oromia zone, Ahmara Region,Ethiopia and cause tremendous losses in terms of property and life, particularly in the lowland areas. Therefore, the study was carried out to perform floodplain analysis, hazard, vulnerability, and flood risk assessment of Borkena catchment. Flood frequency analysis for 2, 5, 10, 50, 100 and 200-years return period was done by Gumbel, Log Pearson Type III, and Log Normal method based on Maximum Instantaneous flow recorded at Swamp outlet station. One dimensional hydraulic model HEC-RAS with HEC-GeoRAS interface was applied for the river analysis. Triangulated Irregular Network (TIN) was prepared from contour using in GIS. Required data sets as stream centerline, banks, flow paths and cross sections were prepared in HEC GeoRAS and imported into HEC RAS. In HEC RAS, boundary conditions for upstream and downstream were defined. Similarly, flood discharges for different return periods were also inputted. Steady flow analysis was used. The results of flood frequency analyzed by Gumbel method showed discharges of 83, 142, 181, 268, 304 and 341m3/s years return period floods, for2, 5, 10, 50, 100 and 200-years which were lower D-index among the results obtained using different methods. Area inundated by 2, 5, 10, 50, 100 and 200-years return period floods were 29.3, 30.6, 32.6, 33.5, 34.2 and 34.9ha respectively. The classification of flood depth area showed most of the flooding area had water depth greater than 3m. The assessment of the flood inundated area showed that large percentage (> 37 %) of vulnerable area lied in grass area followed by cultivation and marsh area, which were 36% and 24% respectively. Flooding of cultivation land indicated potential damages in food production and negative effects on the livelihoods. The findings of the study may help in planning and management of flood plain area. The most important was that a surface water planning strategy, is required to mitigate flood consequences. The presence of risk assessment mapping will help the concerned authorities to formulate their development strategies according to the available risk to the area | en_US |
| dc.language.iso | en | en_US |
| dc.subject | Hydraulic engineering | en_US |
| dc.title | FLOODPLAIN ANALYSIS AND RISK ASSESSMENT OF BORKENA CATCHMENT | en_US |
| dc.type | Thesis | en_US |
