Bank erosion in a Danish lowland stream system

This paper deals with quantification of bank erosion in an entire lowland s tream system and its contribution to suspended sediment export from the str eam basin. Bank erosion was measured at 33 stream reaches over a one-year p eriod and suspended sediment transport concomitantly determined near the ou tlet of the stream system. There was considerable spatial variation in bank erosion within the stream system, erosion being most severe on the unprote cted lower parts of the banks. No relationship could be established between stream bank erosion and land use, although erosion was lower in forest str eams than in streams on land used for grazing cattle. For the stream system as a whole the erosion rate was 11 mm y(-1) for each bank, or 0.020 m(3) p er m stream reach. This corresponds to a total of 2000 tonnes bank material , of which the <63 mu m fraction accounted for 20-30% (no sample pre-treatm ent). In comparison, total annual export of suspended sediment from the str eam system amounted to 675 tonnes.