CHANGES IN THE SALT RIVER, TRIBUTARY TO THE KNYSNA ESTUARY, SOUTH AFRICA: 1936–1998

ABSTRACT

Rapid changes in the lower Salt River, a tributary to the Knysna estuary, southern Cape, is documented through the use of an air photo time series. The evidence plotted for the flood plain and estuary, over the period 1936–1998, demonstrates rapid changes in the channel course, the loss of an extensive Phragmites australis bed and siltation of the estuary. Land use changes in two western catchments particularly impacted on the hydrology. The validity of local oral evidence is confirmed. The floods in 1996 exacerbated siltation by impacting on a development in the upper Simola catchment. Sedimentation in the estuary was greater than previously recorded. The presence of coversand on interfluves and valley heads renders the entire catchment, an area of landscape sensitivity, susceptible to rapid change.