Contribution of saturated areas and hillslopes to the water and element fluxes exported during a storm event: tracing with dissolved organic carbon and silica. The Strengbach catchment case study (Vosges, France)

Two contributing areas have been determined in the small forested Strengbac h catchment by using disserved organic carbon (DOC) and dissolved silica as the most efficient chemical tracers of stream water origin during a storm event. Disserved silica represents the deep layers of the hillslopes which contributes 71-75 % of the total storm runoff and 85-99 % of the fluxes of major elements exported by the Strengbach. DOC corresponds to the saturated areas which occupy only 2 % of the total catchment area but which supply 2 5-29 % of the total streamflow and 56 % of the DOC stream flux. The specifi c fluxes of water (L.s(-1)ha(-1)) and elements (kg.ha(-1)) are much more im portant in the saturared areas than in the rest of the catchment. ((C) Acad emie des sciences/Elsevier, Paris.)