Land use change as a contributing factor to sedimentation rates in the Hazelmere Catchment, KwaZulu-Natal, South Africa.

Abstract

Hazelmere Dam situated on the Mdloti River in KwaZulu-Natal has, since its completion in 1977, lost 25 % of its original design capacity through sedimentation. This storage loss has brought about an environmental concern as well as a socio -economic threat to the region. The aim of this research was to investigate the effect of land use change on the sedimentation rate in the catchment. This was undertaken to obtain a better understanding of the processes and leads towards an integrated catchment management strategy. Geographical information systems afforded the opportunity to determine land use change from a number of sequential land use maps and to run statistical analyses and overlays. It was determined that a large change in land use had taken place between subsistence cultivation/small-scale agriculture and subsistence grazing. The rainfall, soil and slope conditions cause the catchment to have a naturally high erosion potential. As a result of the interrelated nature of all these factors in the catchment the most effective manner in which to deal with the sedimentation problem is through a multidisciplinary approach such as is afforded by integrated catchment management strategies. In terms of controlling the sedimentation problem in the Hazelmere Dam recommendations concerning conservation practices necessary in minimising the impact of the land use practices and changes are made for inclusion in such a management approach.