Forestry effects on suspended sediment and bedload yields in the Balquhidder catchments, Central Scotland

Abstract

ABSTRACTOutputs of suspended sediment and bedload from the 7·7 km2 moorland Monachyle basin and the 6·8 km2, 40%-forested Kirkton basin near Balquhidder, and inputs from tributary streams and mainstream bank erosion, are compared. Sediment yield is about three times higher in the forested basin and varies more sensitively with streamflow, suggesting greater availability of erodible sediment. The output is predominantly of suspended sediment and is derived mainly from tributary streams. Initial observations following partial moorland ploughing and forest clearfelling in 1986 indicate that erosion of timber loading areas and logging roads is the main sediment source.