Runoff and interrill erosion on sandy soils under cultivation in the western Paris basin: mechanisms and an attempt at measurement

Abstract

Measurements made on different scales, such as rainfall simulations on 1 m 2 and 20 m 2 experimental plots and water sampling at the outlet of a watershed, enable the analysis of the mechanisms of pluvial erosion and therefore the importance of runoffs and soil losses in the hilly and sandy parts of the western Paris basin. Interrill erosion accounts for slow transfer of materials towards the lower part of plots and slopes. The overland flow caused by restructuring of the surface Tertiary and Cenomanian soils erodes some 150 to 200 kg ha 1 during the month following sowing. Only a part of these deposits reach the river, which carries away less than 50 kg ha 1 each month. Interrill erosion makes slopes still more uneven, fills in valley bottoms, and so paves the way to catastrophic erosion, which scoops out rises in the ground and colluvial deposits in the lower part of slopes and valley bottoms.

Silting in the Grand Canal in the Domain of Chantilly (Oise, France)—Catchment-Scale Hydrogeomorphological Reconnaissance and Local-Scale Hydro-Sedimentary Transport Modelling

“…In fact, after a bibliographical review, it appears that the Paris basin has mainly been studied (from the point of view of specific degradation) in its western part [25], and that the values given are 16 and 21 t•km −2 •yr −1 for the Austreberthe and Andelle basins. In France, for the Royeau basin (Le Mans region), this value has been evaluated at 57 t•km −2 •yr −1 [26], whereas the Caux country [27] presents values that vary between 140 and 240 t•km −2 •yr −1 . In Lower Normandy, the Traspy basin is given an average value of 60 t•km −2 •yr −1 [28].…”