Hydro-geotechnical assessment of a proposed embankment dam site on a southern rift deltaic plain, Ethiopia
By: Gidday, Biruk Gissila
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Contributor(s): Gebregiorgis, Yoseph Birru.
Publisher: New York Springer 2022Edition: Vol.52(3), June.Description: 590-609p.Subject(s): Civil EngineeringOnline resources: Click here
In:
Indian geotechnical journalSummary: The environment of the southern rift deltaic plain developed at the base of rift escarpment into the Lake Abaya is a transitional buffer between the water body and chain of mountain. The flooding, erosion, and sediment depositions have recurrently been affecting the deltaic community and the high traffic movement from central Ethiopia to the southern corridors. Hence, the upstream catchment study and construction of an Earth-filled embankment dam have been proposed to marginalize the exceedances. The upstream catchment geomorphological characteristics in response to the rainfall have been evaluated using ArcGIS tools. Intensive field observations and tests such as bulk density, moisture content, borehole drilling (sampling, SPT, field permeability), and geoelectrical survey have been carried out. Soil characteristics have been determined based on laboratory tests such as sieve analysis, hydraulic conductivity, shear strength, 1D consolidation. The field SPT value has been correlated with the finer content of the soil to evaluate the liquefaction susceptibility of the sit. The soil investigation result confirmed that the dam foundation consists of deep alluvial overburden with the potential liquefaction susceptibility of 22–34%. The optimum height of an embankment dam is calculated as 25 m using an iterative analytical and numerical model. This integrated hydrological and geomorphological analysis shows that the upstream catchment is highly vulnerable to erosion and hence requires rehabilitation. As a result, for a similar hydro-geomorphological catchment, analytical and numerical modeling of coupled upstream watershed and foundation characteristics can be used.
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Articles Abstract Database
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School of Engineering & Technology (PG) Archieval Section | Not for loan | 2022-1543 |
The environment of the southern rift deltaic plain developed at the base of rift escarpment into the Lake Abaya is a transitional buffer between the water body and chain of mountain. The flooding, erosion, and sediment depositions have recurrently been affecting the deltaic community and the high traffic movement from central Ethiopia to the southern corridors. Hence, the upstream catchment study and construction of an Earth-filled embankment dam have been proposed to marginalize the exceedances. The upstream catchment geomorphological characteristics in response to the rainfall have been evaluated using ArcGIS tools. Intensive field observations and tests such as bulk density, moisture content, borehole drilling (sampling, SPT, field permeability), and geoelectrical survey have been carried out. Soil characteristics have been determined based on laboratory tests such as sieve analysis, hydraulic conductivity, shear strength, 1D consolidation. The field SPT value has been correlated with the finer content of the soil to evaluate the liquefaction susceptibility of the sit. The soil investigation result confirmed that the dam foundation consists of deep alluvial overburden with the potential liquefaction susceptibility of 22–34%. The optimum height of an embankment dam is calculated as 25 m using an iterative analytical and numerical model. This integrated hydrological and geomorphological analysis shows that the upstream catchment is highly vulnerable to erosion and hence requires rehabilitation. As a result, for a similar hydro-geomorphological catchment, analytical and numerical modeling of coupled upstream watershed and foundation characteristics can be used.
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