The Gauteng Regional Office has for some time identified the need to control, monitor and audit all point sources in the Mooi River catchment more effectively. The method used is to instruct all direct impactors to complete a strategic water management plan to ensure their effective management of the activities total water balance. The water quality management plans should include, amongst other aspects, the following:
Water quality management measures in order to minimise pollution should be implemented at source. The fundamental principle is to prevent, inhibit, retard or stop the hydrological, chemical, microbiological, radioactive or thermodynamic processes, which result in the contamination of the water environment.
If the water/waste water problems cannot be solved by the above water quality management measures at source, water/waste water reuse and minimisation measures should be implemented. This includes the prevention of the inflow of ground and surface water into the industry and mining related activities.
If the water/waste water problems cannot be solved by reuse and minimisation measures, then water/waste water treatment applications should be implemented.
It should be appreciated that all of the above entails intensive negotiations between the relevant role players including catchment forums, consultants and specialists where necessary. This ensures participation, collaboration and transparency in decision making.
To assess the extent of water use in the catchment, impactors were requested to initiate, in collaboration with the Region, water user assessments in the catchment. The results are captured in Appendix 1.
The application of water quality management measures has resulted in specific actions being taken to address the sites showing elevated levels of radioactivity. These are as follows:
West Driefontein Gold Mine (Site 7a)
The source of the water at Site 7a is excess mine water which is a mixture of recycled underground water, stormwater and final sewage effluent. The mine is currently investigating all options to control at source, reuse and minimise their excess water. This investigation includes the quantification of their total impact on the water environment.
Doornfontein Gold Mine (Site 12)
The source of the water at Site 12 is excess mine water which is a mixture of recycled underground water and fissure water. The mine has investigated all options to control at source, reuse and minimise their excess water. This investigation included the quantification of their total impact on the water environment. The permit application was lodged at Department of Water and Sanitation in December 1998.
Both these sites have been identified as currently not posing a threat for use as drinking water in the short term. Further investigation will be required to establish whether the water quality is radiologically acceptable in the long term.
As part of their functions in the catchment the Gauteng Region undertakes river and audit monitoring at point sources. The analysis of chemical uranium at specifically identified sites was initiated during phase 1 of the study. Following phase 1 of the study the routine monitoring program has been extended to include the sites of elevated activity.