Integrated assessment of the environmental impact of an IDP camp in Sudan based on very high resolution multi-temporal satellite imagery

Abstract

Population displacement due to armed conflicts, regional crises, or natural disasters often leads to large-scale settlements that impact the local environment. The specific dynamics of such semi-permanent settlements, comprising both the structural changes (to the extent of the camp, and the population density), and their wider impacts on the surroundings, require adaptive monitoring capacities. In areas where livelihoods and food security are highly dependent on natural resources, environmental deterioration can result in violent conflicts over access to, or control of, scarce natural resources, or in renewed migration of the population. Remote sensing, and in particular very high spatial resolution satellite imagery, can help determine the actual population dynamics, together with environmental changes in the surrounding areas. In an ex-post assessment using three time slices (2002, 2004, 2008) we assessed the changing environmental conditions and the resulting implications for human security and ecosystem integrity in the vicinity of a large internally displaced persons (IDP) camp in northern Darfur, Sudan. We used a Weighted Natural Resource Depletion index that integrates selected land use/land cover target classes and their relative importance for human security and/or ecosystem integrity by incorporating weightings assigned by experts to each of these classes. The results showed that the dramatic increase in the camp's population between June 2002 and May 2008 (from approximately 1200 to about 50,000 inhabitants) and areal extent (a growth of ~436%) was accompanied by a noticeable decrease in the area covered by single shrubs and small trees (~ −68%), in the area covered by patches of shrubs and trees (~ −34%), and in the area covered by grassland (~ −3%). Moreover, a marked expansion in small-scale farming was observed, especially into fertile wadi soils. Almost 45% of all grid cells (60m×60m) had experienced at least some degree of depletion of natural resources (i.e. woody vegetation, grassland, etc.) between 2002 and 2008. Major depletion was observed in the north-eastern and eastern parts of the camp in particular, while minor depletion occurred over almost all of the study area.