The effects of check dams on sediment transport dynamics on steep slopes
Effets des barrages de correction torrentielle sur la dynamique du transport solide des torrents
Abstract
Check dams have long been used to stabilize stream beds in mountain areas. Several approaches (including morphological and mechanistic) have been used for designing the spacing and dimensions of these works, with the objectives of limiting bank erosion and to control local slopes. However, little is actually known about how much check dams influence the bedload discharge in a given stream. Do they change the peak bedload discharge and/or do they limit the transported volumes for a given hydrological event? To answer this question we performed several flume experiments, on steep slopes, both with and without check dams. The outlet bedload discharge was measured and analyzed in term of quantity and frequency. We observed that the natural fluctuations of bedload transport were impacted by the presence of check dams, leading to a lowering of the erosion volumes and an increase in fluctuation frequencies.