The high islands of the Pacific are characterised by short and steeply-sloping watersheds, where erosive events can generate large terrigenous material run-off loads that threaten the adjacent reefs. To assess the sediment deposition it is necessary to characterize the erosion process on the watersheds and to highlight the areas most affected. This article aims to describe the implementation of the Universal Soil Loss Equation (USLE) for the mapping and quantification of the potential soil erosion in these countries. The USLE model, commonly used to calculate average annual soil loss per unit land area resulting from sheet and rill erosion, can be written as A=R*E*L*S*C*P. A is the soil loss, R is the rainfall-run off erosivity factor, E is a soil erodibility factor, L is a slope length factor, S is a slope steepness factor, C is a cover management factor and P is a supporting practice factor. The spatialization of this model is implemented using the data processing and mapping functionalities of a Geographical Information System (GIS) from input data which included a digital elevation model, a soil map, a land cover map and precipitation data. In this paper, the methodology developed for each parameter and the results on New-Caledonia site will be presented.
Erosion, Universal Soil Loss Equation (USLE), Integrated Coastal Zone, Management (IZCM), Geographical Information System (GIS), New Caledonia
Axe de recherche : Dynamiques, gouvernance et durabilité des territoires insulaires