Contribution of concentrated runoff to the erosion of cultivated sandy soils in the west of the Paris basin: the example of the Dué and Narais watersheds

Abstract

From 1988 to 1995, we have studied several small watersheds located in the western Paris basin, west to Le Mans, in order to assess the concentrated runoff contribution to erosion on sandy soils. During rainfall periods, it has been possible to observe the formation of rills and gullies, to cartography and measure the features due to erosion, and so to assess the soil losses due to concentrated runoff. Chronic erosion, which produces transfers of deposits from upslope to dry dell bottoms, has been relayed in two occasions (in May 1998 and in May 1990) by catastrophic erosion, which incises the previous sandy accumulations and exports a part of these deposits towards the main rivers. Those coarsed discharges have modified stream dynamics. Preventive actions are suggested.