Dynamic modelling for linear erosion initiation and development under climate and land-use changes in northern Laos》.pdf

Catena 63 (2005) 318–328 /locate/catena Dynamic modelling for linear erosion initiation and development under climate and land-use changes in northern Laos V. Chaplot a,b,*, G. Giboire b, P. Marchand b, C. Valentin b aCentre IRD d’Ile de France, 32, avenue Henri Varagnat- 93143 Bondy Cedex, France bInstitut de Recherche pour le De´veloppement (IRD)/International Water Management Institute (IWMI)/National Agricultural and Forestry Research Institute (NAFRI), Vientiane, (PDR) LAOS Abstract Linear erosion (LE) induced either by piping or overland flow is one of the most active factors in the evolution of soils. During single storm events LE may remove enormous amounts of soil material from the uplands to the bottomlands and has thus become a broad challenge for food supply, food security, and human health. Recent and rapid changes in land-use and climate patterns in the sloping lands of tropical areas may dramatically increase LE. Our main objective was to investigate to what extent one could use direct flow velocity estimations from dynamic models for predicting LE initiation and development at the event level. The second objective was to estimate the impact of expected land-use and climate changes on LE. The study was conducted in the 0.62 km2 watershed of northern Laos presented in Chaplot et al. (2005). Field observations of the formation and the development of LE features throughout 2001 were compared to flow velocity estimations from an existing surface water routing algorithm developed at Utrecht University ([De Roo, A.P.J., Wesseling, C.G. and Ritsema, C.J. 1996. LISEM: a single event physically based hydrologic and soil erosion model for drainage basins. I: theory, input and output. hydrologi