|
The relative generalised catchment land-cover of 62 estuaries is presented in graphical format. A summary report (as a PDF file), outlining the approach and results for each estuarine catchment, is also available.
The catchments of estuaries in KwaZulu-Natal (Kosi Bay-Mtamvuna) had a relatively high proportion of commercial agriculture (>20%). There was also a relatively high proportion (>20%) of agriculture in the catchments of estuaries in the Transkei region of the Eastern Cape (Mtamvuna-Great Kei). This, however, primarily consisted of subsistence farming. Those systems in the Western Cape (Keurbooms-Olifants) had this highest proportion (>40%) of agriculture in their catchments and this was mainly commercial.
Estuaries situated in predominantly rural areas, particularly in the Transkei (Mtamvuna-Great Kei) and Ciskei (Tyolomnqa-Great Fish) regions of the Eastern Cape had the highest proportion of degraded land-cover in their catchments. Most catchments had over 10% degraded land-cover with many exceeding 20%. This is probably a result of poor farming practices.
Most estuaries had a relatively high proportion of natural land-cover in their catchments, usually exceeding 50%. Estuaries in the southwest region of the Eastern Cape (Great Kei-Kromme) had the highest proportion of natural land-cover, generally exceeding 70% and often as high as 80-90%. Those estuaries with very large catchments, generally above 20 000 sq. km such as the Thukela, Mzimvubu, Great Kei, Great Fish, Sundays, Gamtoos, Gourits, Olifants and Gariep also had a high proportion of natural land-cover (>70%).
A relatively high proportion of urban land-cover was associated with those estuaries located near coastal cities such as the Mgeni and Durban Bay near Durban, the Buffalo system near East London, the Swartkops estuary near Port Elizabeth, and the Diep estuary near Cape Town. Relatively high residential development was also apparent in the rural areas of the Eastern Cape (Transkei and Ciskei). This is probably a result of a relatively high population density in this region.
This analysis provides a unique, quantitative measure of land-cover in the catchments of the major estuaries along the South African coast, using remote sensing data. It serves as a valuable measure of the state of environment of these systems as well as a useful tool for planners and managers. These results can also be used as a baseline against which future changes in catchment land-use can be monitored.
|
Summary Report
