Spatial distribution and livelihood effects of debris cones at the western Afar Rift Valley margin, northern Ethiopia

The objective of the study on which the article is based was to investigate the distribution, characteristics and livelihood effects of debris cones in the Aba'ala and Raya grabens in Ethiopia. The characteristics of the debris cones and their upper catchment areas were obtained from Google Earth Pro and Landsat images. Questionnaires were used to understand the livelihood effects of the debris cones. In addition, transect studies, interviews and observations were used to supplement the data. The data were analysed using descriptive statistics, a regression model and coupled criteria. The results showed that the debris cones differed in their physical characteristics and distribution, and their volumes were larger in the Raya graben than in the Aba'ala graben. The average flow lengths of the upper catchments was the major predictor of debris cone volume. The expansion of debris cones devastated farmlands, resulting in crop yield loss. Moreover, deposited debris damaged dwellings and pasture, and led to smallholder farmers' displacement. However, the cones remained attractive for settlement and spate irrigation. The authors conclude that despite the benefits of debris cones, catchment rehabilitation measures should be implemented in the upper catchments to reduce the expansion of debris cones in the studied grabens.