Drought conditions and sediment transport in the Sabie River

Abstract

Sediment production within the catchment is largely unaffected by a reduction in the frequency and magnitude of rainfall events, although the rate of translocation of the weathered material from the catchment into the river channel is noticeably altered. The infrequent storm events during drought conditions generate a greater sediment input to the river from the catchment than a similar-magnitude event under averaged conditions. This sediment is also less likely to be transported through the system due to the reduced frequency of intermediate flows which act to rework in-channel sediment accumulations. The 1992 drought resulted in a significant build-up of sediment in some areas. This sediment is becoming stabilised due to the lower and less variable flows of the recent drought and associated vegetative colonisation. -from Authors