Article Sidebar
Published:
Nov 4, 2023DOI:
10.4314/mejs.v15i2.2Keywords:
Article Details
The Momona Ethiopian Journal of Science accepts the manuscripts for consideration with the understanding that the manuscript has not been published and is not under consideration for publication elsewhere. Only original articles will be considered for publication if they have been published previously as abstracts, but not if they have been published previously as extended abstract (>1000 words). This applies to both electronic and print versions of the journal. The authors should assign copyright ownership to the Editorial Office of MEJS in the event that the manuscript is accepted for publication in the Momona Ethiopian Journal of Science. All accepted manuscripts must be accompanied by a copyright statement signed by all authors. A copy of the copyright form will be supplied along with the final reviewed version of the manuscript that is sent for final proof- reading. Authors may make multiple copies of the form if necessary and send to the Editorial Office with author’s signature(s) even individually.
All articles published by Momona Ethiopian Journal of Science (MEJS) are Open Access under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0). Under this license, authors retain ownership of the copyright for their content, and anyone can copy, distribute, or reuse articles as long as the author and original source are properly cited. In all these cases for re-use, the authors will be given proper credit to the original publication in MEJS.
Main Article Content
An Engineering Geological Appraisal of the Leakage Problem in Dora-1 Earthen Dam, Tigray: Implications for its Stability
Abstract
Leakage is one of the major problems facing the functionality and sustainability of dams. It occurs through the embankment body, reservoir, foundation, and abutments. This study was conducted to identify the main causes of the leakage problem at the Dora-1 dam, located in the northern part of Ethiopia. It is an earthfill dam with a height of 43.5 m, crest length of 454 m, and reservoir capacity of 4.67 million cubic meters. Part of the embankment body was wet and swampy up to 20 m high from the ground due to leaking water. Geological investigation, laboratory test of the construction materials (including grain size analysis, specific gravity and water absorption, Atterberg limit, free swell, dispersion, permeability, and shear strength), and electrical resistivity investigation were used to identify and pinpoint the possible causes of the leakage problem. Results of the study show that the favorable geological features responsible for the occurrence of leakage include: (a) geological contact between sandstone and moderately to highly weathered basalt unit at the left abutment, (b) the gravelly sand deposit at the central foundation and (c) dyke outcrop at the river course within the reservoir running in the upstream-downstream direction. Results of laboratory tests for clay core show medium to high compressibility, good to poor workability, and semi-pervious to impervious permeability when compacted. The water absorption and the percentage finer of the filter material don’t satisfy the filter criteria and the shell material was found to be semi-previous. The anomalous in the resistivity survey result confirms the situation. Slope stability analysis of the embankment showed instability conditions at full reservoir level. Close follow-up and a downstream stabilization structure, including rock and gravel support, were recommended.
Construction material; Embankment dam; Site investigations; Ethiopia.
