Patterns of erosion and sediment production in Hong Kong

Abstract

A series of maps is presented to illustrate the distribution of erosion in Hong Kong. Erosion has been widespread, but the latest map reveals that its spatial extent may be declining. This may reflect afforestation and the reduced utilization of vegetation as a source of fuel. Based upon accumulated quantities of sediment in submerged and lined sections of some river channels, estimates of annual sedimentation rates are given and are shown to be quite variable. Variability is reduced if consideration is given to basin size. Very high loadings of agricultural waste contribute to sedimentation in some rivers. Drainage Services Department data also confirm the spatial variability of sedimentation. Temporal variability of sediment production is illustrated with data from a small basin.