Land 2017, 6(4), 78; https://doi.org/10.3390/land6040078
Impact of Soil Depth and Topography on the Effectiveness of Conservation Practices on Discharge and Soil Loss in the Ethiopian Highlands
Adugnaw T. Akale 1, Dessalegn C. Dagnew 2, Mulugeta A. Belete 1, Seifu A. Tilahun 1, Wolde Mekuria 3 and Tammo S. Steenhuis 1,4,*
1
Faculty of Civil and Water Resources Engineering, Bahir Dar Institute of Technology, Bahir Dar University, P.O. Box 26, Bahir Dar, Ethiopia
2
Institute of Disaster Risk Management and Food Security Studies, Bahir Dar University, P.O. Box 5501 Bahir Dar, Ethiopia
3
International Water Management Institute (IWMI), East Africa and the Nile Basin Sub-Regional Office, P.O. Box 5689, Addis Ababa, Ethiopia
4
Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
*
Author to whom correspondence should be addressed.
Received: 12 September 2017 / Revised: 29 October 2017 / Accepted: 31 October 2017 / Published: 3 November 2017
(This article belongs to the Special Issue The Impact of Land Use Change on Water Resources, Soil and Landforms: Perspectives from Multiple Climates)
Abstract
Restoration of degraded landscapes through the implementation of soil and water conservation practices is considered a viable option to increase agricultural production by enhancing ecosystems. However, in the humid Ethiopian highlands, little information is available on the impact of conservation practices despite wide scale implementation. The objective of this research was to document the effect of conservation practices on discharge and sediment concentration and load in watersheds that have different soil depths and topography. Precipitation, discharge, and sediment concentration were measured from 2010 to 2012 in two watersheds in close proximity and located in the Lake Tana basin, Ethiopia: Tikur-Wuha and Guale watersheds. The Tikur-Wuha watershed has deep soils and a gentle slope stream channel. The Guale watershed has shallow soils and a steep slope stream channel. In early 2011, the local community installed upland conservation measures consisting of stone and soil bunds, waterways, cutoff drains, infiltration furrows, gully rehabilitation, and enclosures. The results show that conservation practices marginally decreased direct runoff in both watersheds and increased base flow in the Tikur-Wuha watershed. Average sediment concentration decreased by 81% in Tikur-Wuha and 45% in Guale. The practices intended to increase infiltration were most effective in the Tikur-Wuha watershed because the deep soil could store the infiltrated water and release it over a longer period of time after the rainy season than the steeper Guale watershed with shallow soils. View Full-TextKeywords:
East Africa; Blue Nile; Lake Tana; runoff; discharge; sediment; erosion; soil depth; soil and water conservation; gully
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Akale, A.T.; Dagnew, D.C.; Belete, M.A.; Tilahun, S.A.; Mekuria, W.; Steenhuis, T.S. Impact of Soil Depth and Topography on the Effectiveness of Conservation Practices on Discharge and Soil Loss in the Ethiopian Highlands. Land 2017, 6, 78.
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