Abstract
The role of engineering geology in the final design and construction of a road crossing the Blue Nile (Abay) gorge in Ethiopia is described. This new road between Mekhane Selam and Gundewein is a strategic link in the Ethiopian road network and encounters very steep and difficult terrain that poses significant engineering geological challenges. Remote sensing, landscape modelling, reference condition classification, and conventional field mapping have been applied to assist in the finalisation of the alignment, the prediction of ground conditions for earthworks design, and the implementation of slope and drainage protection works. The approach adopted serves as a blueprint for other road construction and improvement projects in the region though limitations exist with respect to the prediction of variable volcanic rock sequences at depth without the benefit of ground investigation boreholes. Although ground conditions different from those predicted have been exposed along 15 % of the alignment, these have been of relatively minor significance and have necessitated unanticipated remedial action affecting less than 2 % of the alignment in the gorge. Thus far, the main damage to the road from geohazards has been caused by road-related effects, including the concentration of road drainage below culverts and seepages from broken and blocked side drains. The susceptibility of the terrain to uncontrolled runoff is such that preventative and reactive maintenance will be required throughout the lifetime of the road.
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Abebe B, Dramis F, Fubelli G, Umer M, Asrat A (2010) Landslides in the Ethiopian highlands and the Rift margins. J Afr Earth Sci 56:131–138
Ayalew L (1999) The effects of seasonal rainfall on landslides in the highlands of Ethiopia. Bull Eng Geol Environ 58:9–19
Ayalew L (2000) Factors affecting slope stability in the Blue Nile basin. In: Bromhead E, Dixon N, Ibsen M (eds) Landslides: research, theory and practice. Thomas Telford, Cardiff, pp 101–106
Ayalew L, Temesgen B (1995) Assessments of slope movements from Gohatsion to Dejen, Blue Nile gorge, Ethiopia. A report submitted to the Ethiopian Science and Technology Commission, Addis Ababa, Ethiopia, p 71
Ayalew L, Yamagishi H (2004) Slope movements in the Blue Nile basin, as seen from landscape evolution perspective. Geomorphology 57:97–116
Ayalew A, Moeller D, Reik G (2009) Geotechnical aspects and stability of road cuts in the Blue Nile Basin, Ethiopia. Geotech Geol Eng 27:713–728
Brown DJ (2007) Technical Note: a guide to the use of volcaniclastic nomenclature in engineering investigations. Q J Eng Geol Hydrogeol 40:105–112
Chumburo F (2009) 1:250,000 scale geological map of Debre Markos Sheet (NC-37-6). Geological Survey of Ethiopia, Addis Ababa
Clark PU, Dyke AS, Shakun JD, Carlson AE, Clark J, Wohlfarth B, Mitrovica JX, Hostetler SW, McCabe AM (2009) The last glacial maximum. Science 325:710–714
Conway D (2000) The climate and hydrology of the Upper Blue Nile River. Geogr J 166(1):49–62
EBCS (1995) Ethiopian Building Code Standard for Seismic Load (EBCS-8). Ministry of Works and Urban Development, Addis Ababa
ERA (2011) Geometric design manual. Ethiopian Roads Authority, Addis Ababa
Fookes PG (1997a) Geology for engineers: the geological model, prediction and performance. Q J Eng Geol Hydrogeol 38:231–284
Fookes PG (ed) (1997b) Tropical residual soils, Geological Society Professional Handbooks, Geological Society of London, Engineering Group Working Party Revised Report, London
Fookes PG, Sweeney M, Manby CND, Martin RP (1985) Geological and geotechnical engineering aspects of low cost roads in mountainous terrain. Eng Geol 21:1–152
Fookes PG, Baynes FJ, Hutchinson JN (2000) Total geological history: a model approach to the anticipation, observation and understanding of site conditions. GeoEng 2000, an international conference on geotechnical and geological engineering, Melbourne, Australia, International Society for Rock Mechanics, Invited Papers. 1, pp 370–460
Fookes P, Pettifer G, Waltham T (in press) Geomodels in engineering geology—an introduction. Whittles Publishing, Dunbeath, Scotland
Gani NDS, Abdelsalam MG, Gera S, Gani MR (2009) Stratigraphic and structural evolution of the Blue Nile Basin, Northwestern Ethiopian Plateau. Geol J 44:30–56
Gebremeskel AG (2011) Ethiopian water resources and the development of Ethiopia. Ministry of Water and Energy, International Water Week/Netherlands Water Partnership, 31 October–4 November 2011. http://www.partnersvoorwater.nl/wp-content/uploads/2011/11/PresentatieontwikkelingintergraalwaterbeheerinEthiopie.pdf
Gezahen A (1998) Slope instability assessment in the Blue Nile gorge. In: Moore D, Hungr O (eds) Proceedings of the 8th International IAEG Congress, Vancouver, Balkema, Rotterdam, pp 1437–1442
Gregg SL (2009) An evaluation of the use of ‘geotechnical reference conditions’ in ground investigation and characterisation during mountain road construction in the Blue Nile Gorge, Ethiopia. MSc Engineering Geological Dissertation, School of Earth and Environment, University of Leeds, UK
Griffiths JS, Stokes M (2008) Engineering geomorphological input to ground models: an approach based on Earth systems. Q J Eng Geol Hydrogeol 41:73–91
Griffiths JS, Stokes M, Stead D, Giles D (2012) Landscape evolution and engineering geology: results from IAEG Commission 22. Bull Eng Geol Environ 71:605–636
Hearn GJ (ed) (2011) Slope engineering for mountain roads. Engineering Geology Special Publication 24, Geological Society of London
Hearn GJ (2014) Promoting sustainable rural access and developing a risk-based vulnerability assessment for rural communities in the changing climate of Sub Saharan Africa. Final Report for the DFID-funded Africa Community Access Programme
Hearn GJ, Hunt T (2013) Route selection manual. Ethiopian Roads Authority, Addis Ababa
Hearn GJ, Massey C (2009) Engineering geology in the management of roadside slope failures: contributions to best practice from Bhutan and Ethiopia. Q J Eng Geol Hydrogeol 42:511–528
Hearn G, Hart A, Morgan C, Wise D, O’Donnell N (2012) Assessing the potential for future first-time slope failures to impact the oil and gas pipeline corridor through the Makarov Mountains, Sakhalin Island, Russia. Q J Eng Geol Hydrogeol 45:79–88
JICA/GSE (2012) The project for developing countermeasures against landslides in the Abay river gorge, Final Report, Kokusai Kogyo Co Ltd, Japan Conservation Engineers Co Ltd, Japan International Cooperation Agency/Geological Survey of Ethiopia
Kebede S (2013) Groundwater in Ethiopia. Springer-Verlag, Berlin and Heidelberg
Kuwano T, Enokida M, Tsukamoto S, Ichikawa K, Nakagawa A, Takeuchi T (2013) Assessment of hazard and contributing factors of landslides in Abay Gorge in Ethiopia. In: Ugai K, Yagi H, Wakai A (eds) Earthquake-induced landslides. Proceedings of the international symposium on earthquake—induced landslides, Kiryu, Japan, 2012, Paper 80, pp 737–744
Nyssen J, Poesen J, Moeyersons J, Deckers J, Haile M, Lang A (2004) Human impact on the environment in the Ethiopian and Eritrean Highlands—a state of the art. Earth Sci Rev 64(3–4):273–320
Ruse M, Lewis I, Lockwood J, Jonsson V, Edmonds V (2013) Engineering geomorphological models of the North-west Yilgarn, Western Australia. Aust Geomech 48(2):27–38
Selby MJ (1993) Hillslope materials and processes. Oxford University Press, Oxford
Sima J et al (2009) Water resources management and environmental protection studies of the Jemma river basin for improved food security. Ministry of Environment of the Czech Republic, Prague
Sultana DN, Abdelsalam MG (2003) Evolution of the Blue Nile Gorge, Ethiopia, from optical and radar remote sensing and digital elevation models data integration. AAPG Annual Meeting, Salt Lake City, Utah, 11–14 May 2003
Tefera M, Chernet T, Haro W (1996a) 1:2,000,000 scale Geological Map of Ethiopia, 2nd edn. Ethiopian Institute of Geological Surveys, Addis Ababa
Tefera M, Chernet T, Haro W (1996b) Explanation of the Geological Map of Ethiopia. Ethiopian Institute of Geological Surveys, Addis Ababa
Woldearegay K (2013) Review of the occurrences and influencing factors of landslides in the highlands of Ethiopia: with implications for infrastructural development. Momona Ethiop J Sci 5(1):3–31
Woodward JC, Macklin MG, Krom MD, Williams MAJ (2007) The Nile: evolution, Quaternary river environments and material fluxes. In: Gupta A (ed) Large rivers: geomorphology and management. Wiley, Chichester, pp 261–292
Yamada M, Ichikawa K, Kuwano T, Takeuchi T, Nakagawa A (2013) The interpretation for landslide mechanism and the proposal of landslide countermeasures in Abay Gorge in Ethiopia. In: Ugai K, Yagi H, Wakai A (eds) Earthquake-induced landslides. Proceedings of the international symposium on earthquake—induced landslides, Kiryu, Japan, 2012, Paper 42, pp 405–416
Acknowledgments
The authors would like to thank the Ethiopian Roads Authority and URS Infrastructure and Environment UK Ltd for permission to publish this paper. The contributions of the following to remote sensing, field mapping, analysis, design, and construction supervision are gratefully acknowledged: Darryn Wise; Jonathan Hart; Colin Chant; Sarah D’Agostino; Phil Talbot; Solomon Kuliche, Lulseged Ayalew; Mesfin Teshome; Seyoum Belew, Kirti Bahadur Thapa; Solomon Assefa; and many others. Drawings were prepared by Karen Finlay. The Mekhane Selam–Gundewein road was constructed by CGCOC (CGC Overseas Construction Group, Beijing). The pre-construction design was undertaken by Renardet. SA/SABA Engineering and their efforts to identify the optimum road corridor formed an important contribution to the final design. Tim Hunt provided comments on the final draft of this paper.
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Gareth James Hearn was formerly with Scott Wilson and URS Infrastructure & Environment UK Ltd.
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Hearn, G.J., Pettifer, G.S. The role of engineering geology in the route selection, design and construction of a road across the Blue Nile gorge, Ethiopia. Bull Eng Geol Environ 75, 163–191 (2016). https://doi.org/10.1007/s10064-015-0724-y
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DOI: https://doi.org/10.1007/s10064-015-0724-y