Eichhornia crassipes in Hartebeespoort Dam (South Africa)
Despite efforts to control, E. crassipes remains South Africa’s most problematic aquatic macrophyte. Hartebeespoort Dam currently is a hotspot of E. crassipes invasion. The plant has been present since the 1970s and was successfully controlled in the 1980s using herbicides.
In 2016, however, herbicidal control was halted, resulting in massive plant growth. A steering committee has been put in place to draw up a control plan, but this excludes the use of herbicides, which to many seems to be the only viable option. The dam is subject to serious anthropogenic pollution, climate change, and hydromorphological alterations. The primary use of the dam is for irrigation, as well as for domestic and industrial use.
The stakeholder in this case study is the Department of Environmental Affairs: Natural Resource Management Programmes.
Top left: Eichhornia crassipes invasion on Hartbeespoort Dam near Pretoria, South Africa. Top right: Sentinel 2 image of Hartbeespoort Dam on 2017-11-03, showing the extent of the macrophyte mass development. Bottom left: small scale manual removal at a housing estate on the Dam. Bottom right: large scale mechanical removal using boats and a conveyor belt at the Dam. Sentinel 2 image by European Space Agency – ESA; other pictures by Julie Coetzee.