Geological challenges in constructing the proposed Geba dam site, northern Ethiopia

  • Gebremedhin BerhaneEmail author
  • Kristine Walraevens
Original Paper


It is proposed to construct a dam across the Geba River, Ethiopia. The paper reports the engineering geological investigations undertaken, including mapping, discontinuity surveys, core drilling, water absorption testing and sampling for laboratory tests. The complexity of the site, with limestones and interbedded limestone-shale horizons, is indicated by the variability of the RQD and Lugeon values. Of the 63 tests undertaken, some two-thirds had Lugeon values implying grouting was necessary. Following removal and replacement of the alluvial deposits in the central area, a grout curtain including two to three rows of grouting holes was recommended to a depth of 100 m for the left abutment, 35 m for the central foundation and 60 m for the right abutment.


Dam site Engineering geological mapping Geba River Lugeon test Northern Ethiopia 


La construction d’un barrage sur le fleuve Geba, en Ethiopie, est projetée. L’article présente les reconnaissances géologiques et géotechniques réalisées, comprenant une cartographie, des levers de discontinuités, des carottages, des essais d’absorption d’eau et des échantillonnages pour les essais de laboratoire. La complexité du site, avec des formations calcaires et des alternances de schistes et calcaires, se traduit par des valeurs de RQD et des résultats d’essais Lugeon très divers. Sur les 63 essais Lugeon réalisés, environ les deux tiers présentent des valeurs impliquant des travaux d’injection. Après l’enlèvement et le remplacement des dépôts alluviaux dans la zone centrale de la fondation, un écran d’injection constitué de deux à trois rangées de forages d’injection a été recommandé jusqu’à une profondeur de 100 m pour l’appui de rive gauche, 35 m pour la partie centrale de la fondation et 60 m pour l’appui de rive droite.

Mots clés

Site de barrage Cartographie de géologie de l’ingénieur Rivière Geba Essai Lugeon Ethiopie du Nord 



The authors are very grateful to the Department of Earth Science of Mekelle University for providing logistic support to conduct the fieldwork. Thanks also to the Flemish Interuniversity Council—University Cooperation for Development (VLIR-UOS) for the short research stay grant at Ghent University, Belgium, which allowed the first author to prepare this article. We appreciate the data provided by the Tigray Water Resource, Mines and Energy Bureau and Addis Geosystems PLC and the opportunity given to the first author to work with them during the investigation program. Thanks are also given to the staff at the Laboratory for Applied Geology and Hydrogeology of Ghent University for their assistance during the work.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  1. 1.Department of Earth Sciences, College of Natural and Computational SciencesMekelle UniversityMekelleEthiopia
  2. 2.Laboratory for Applied Geology and HydrogeologyGhent UniversityGhentBelgium

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