Rand Water has embarked on an integrated approach to manage the situation. This involves physical removal, biocontrol, and chemical application. It has also been agreed by experts that this type of approach is most suitable at present.

The use of herbicides is therefore not used in isolation. The application of all herbicides used on the project has been approved by both the Department of Forestry, Fisheries and the Environment and the Department of Water and Sanitation South Africa and they are set at a sub-lethal dose because we are implementing an integrated approach.

The sub-lethal dose actually increases the sugar and carbohydrate contents of the Pontederia crassipes plant making it more palatable for the biocontrol agent. The specific formulations of the glyphosate that were recommended are made based on their expert opinion and research and this field work is being monitored for compliance at present.

Although biocontrol agents are already on the Vaal Barrage, additional biocontrol agents will be released on 15 February (should weather conditions permit it).

They will hopefully be released in the upper reaches of various water bodies (stream inlets) on the Barrage as well as in some selected areas between reed beds on the Barrage. More details on this will be provided closer to the time.