HOSTED BY Original Research Article Estimating landscape susceptibility to soil erosion using a GIS-based approach in Northern Ethiopia Lulseged Tamene a , Zenebe Adimassu b,n , Ermias Aynekulu c , Tesfaye Yaekob d a International Center for Tropical Agriculture (CIAT), Chitedze Agricultural Research Station, P.O. Box 158, Lilongwe, Malawi b International Water Management Institute (IWMI), PO. Box 5689, Addis Ababa, Ethiopia c Agroforestry Center, UN Avenue, Gigiri, Nairobi, Kenya d Ethiopian Institute of Agricultural Research (EIAR), P.O.Box 2003, Addis Ababa, Ethiopia article info Article history: Received 23 October 2016 Received in revised form 1 May 2017 Accepted 3 May 2017 Available online 26 May 2017 Keywords: Revised universal soil loss equation Sediment delivery ratio Hot-spot areas Watershed Sediment deposition abstract Soil erosion is a very critical form of land degradation resulting in the loss of soil nutrients and down- stream sedimentation of water storages in the highlands of Ethiopia. As it is technically and financially impossible to conserve all landscapes affected by erosion, identification of priority areas of intervention is necessary. Spatially distributed erosion models can help map landscape susceptibility to erosion and identify high erosion risk areas. Integration of erosion models with geographic information systems (GIS) enables assessing evaluate the spatial variability of soil erosion and plan implementing conservation measures at landscape levels. In this study, the Revised Universal Soil Loss Equation adjusted for sedi- ment delivery ratio was used in a GIS system to assess landscape sensitivity to erosion and identify hotspots. The approach was applied in three catchments with size being 10–20 km 2 and results were compared against quantitative and semi-quantitative data. The model estimated mean soil loss rates of about 45 t ha À1 y À1 with an average variability of 30% between catchments. The estimated soil loss rate is above the tolerable limit of 10 t ha À1 y À1 . The model predicted high soil loss rates at steep slopes and shoulder positions as well as along gullies. The results of the study demonstrate that knowledge of spatial patterns of high soil loss risk areas can help deploy site-specific conservation measures. & 2017 International Research and Training Center on Erosion and Sedimentation and China Water and Power Press. Production and Hosting by Elsevier B.V. This is an open access article under the CC BY-NC- ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction Soil erosion is a fundamental problem in Ethiopia with tre- mendous impact on soil quality, land productivity, water pollution and sedimentation (e.g.,Tamene, Park, Dikau, & Vlek, 2006a; Hurni, 1983). In many areas of the mountainous regions of northern Ethiopia, erosion has caused critical loss of topsoil and rapid sil- tation of water harvesting reservoirs (Adimassu, Mekonnen, Yirga, & Kessler, 2014; Tamene et al., 2006a; Tilahun, Esser, Vägen, & Haile, 2002). To tackle the on- and off-sites damages due to ero- sion,adequate information on the rates and determinants of soil loss as well as spatial distribution of major sediment sources are needed. Since there are wide differences in the rates of sediment yield from different landscape units and application of conserva- tion measures to all areas experiencing erosion is uneconomical and undesirable, conservation measures should be targeted to critical areas experiencing high soil loss. Identification of “hotspot” areas of erosion is therefore imperative from economic, manage- ment and sustainability point of view. Soil erosion models are commonly used to investigate the physical processes and mechanisms governing erosion rates and identifying high risk areas of soil loss to aid conservation planning (Jetten, Govers, & Hessel, 2003; Mitasova, Batron, Ullah, Hofierka, & Harmon, 2013). Recent advances in the development of Geo- graphic Information System (GIS) have promoted the application of distributed soil erosion and sediment delivery models at catchment scales (Kamaludin et al., 2013; Mitasova et al., 2013; Tanyas, Kolatb, & Süzenc, 2015). Studies show that terrain shape and topographic complexity play dominant role on the spatial variation of hydrological pro- cesses at the catchment scale (Desmet & Govers, 1996a; Mitasova, Hofierka, Zloch, & Iverson, 1996; Van Oost et. al., 2000). Model formulation with topography being treated in more detail may thus allow reproduction of the basic patterns of erosion and de- position in complex landscapes (Wilson & Gallant, 2000). Soil erosion models that emphasize terrain can be the best compro- mise between the availability of input data and the reliability of soil loss estimates (Ferro, Di Stefano, & Minacapilli, 2003). The slope steepness-length component of the Universal Soil Loss Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/iswcr International Soil and Water Conservation Research http://dx.doi.org/10.1016/j.iswcr.2017.05.002 2095-6339/& 2017 International Research and Training Center on Erosion and Sedimentation and China Water and Power Press. Production and Hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). n Corresponding author. E-mail address: zenebeteferi@yahoo.com (Z. Adimassu). Peer review under responsibility of International Research and Training Center on Erosion and Sedimentation and China Water and Power Press. International Soil and Water Conservation Research 5 (2017) 221–230