Department of Water Affairs and Forestry
Upper Vaal Water Management Area

LEEU TAAIBOSCHSPRUIT FORUM

Home About us Forum Management Committee Technical Committee Public Relations Committee Finance/Admin Committee Radar Scanning Committee Contact us
Function
Members
Water Quality
Projects
CMA Process
Meetings & Minutes

Water Quality in the Leeu Taaiboschspruit Catchment

The Department of Water Affairs and Forestry conducts water sampling on a monthly basis within the Leeu Taaiboschspruit Catchment. The results of this monitoring are compared to water quality objectives for the Catchment.

 What are water quality objectives you ask? Water Quality Objectives, or WQOs, describe the quality of water that must be maintained within a watercourse or river that will ensure that it is fit for use. The main water uses within this Catchment include domestic, agricultural, industrial, mining as well as some recreation. Basically, we formulate WQOs to ensure that the needs of all of the water users are met. Another important consideration is users downstream in the Vaal River. This is a strategic watercourse within the country, and we must ensure that the water leaving our Catchment is fit for downstream users. In the same way the users situated upstream of our Catchment must ensure that the water that leaves their Catchment is fit for our various uses. 

 The Vaal Barrage Catchment Executive Committee, or VBCEC, has finalised WQOs for the Vaal Barrage. The LeeuTaai Forum Technical Committee is in the process of setting WQOs for the Taaiboschspruit and the Leeuspruit. 

 This article will provide a brief overview of the water quality in our Catchment. It will look at water quality for 2002 at 4 strategic points:

1.      The first point within our Catchment the Vaal River just downstream of the Vaal Dam

2.      The Taaiboschspruit before it flows in the Vaal River

3.      The Leeuspruit before it flows in the Vaal River

4.      The last point within our Catchment the Vaal Barrage

It is not possible to discuss all the monitoring variables in such a brief article, but this article will make use of a good indicator to discuss water quality, namely Electrical Conductivity (EC). EC basically indicates the amount of salts dissolved in the water sample. Salt loading is a major concern within the Vaal River, and also therefore in the tributaries that feed into the Vaal River, including the Taaiboschspruit and Leeuspruit.

Point 1: The upper-most point in our Catchment, the Vaal River just downstream of the Vaal Dam

This is the best water quality within the Catchment, as indicated by the low EC values of 21mS/m. This point is above all the impactors within our Catchment. There are however notable spikes when the EC peaked at 60mS/m and 40mS/m. These variations are seasonal. The Department of Water Affairs and Forestry regularly releases good quality water from the Vaal Dam, which brings down the EC values. These releases are necessary to maintain reasonable quality water further downstream.  During the dry months, the WQO of 30mS/m (indicated in red) was exceeded. The trend as indicated by the green line indicates that the EC will increase and water quality will deteriorate. The EC is however currently well within the WQO limit set.

 

Point 2: The Taaiboschspruit before it flows into the Vaal River

   

 It is clear that water quality within the Taaiboschspruit is not as good as the Vaal River at the Lethabo weir. This watercourse is negatively impacted by various industrial effluent discharges. The green trend line indicates that the EC will continue to increase i.e. water quality will continue to deteriorate. The EC is currently at 78mS/m. Various measures are currently being investigated to improve the water quality of this watercourse. Such measures involve both point source reduction i.e. reducing harmful discharges, as well as resource directed measures which concentrate on the water resource itself, such as setting WQOs. Once the WQOs have been finalised, work can begin on a Catchment Management Plan that will provide guidance and methods to improve the water quality within the entire Catchment.

 

Point 3: The Leeupruit before it flows into the Vaal River

   

 The water quality within the Leeuspruit is only slightly better than that of the Taaiboschspruit. Although there are no point source discharges into this watercourse, it is negatively impacted by runoff and seepage from various industrial and mining activities as well as contamination from sewage pollution incidents such as pump station failures. The green trend line similarly indicates that EC will continue to increase.  The EC is currently just below 65mS/m. Both resource and source directed measures will be implemented within the Catchment of this watercourse to improve its water quality. These measures will be investigated and implemented by the Department of Water Affairs and Forestry, in conjunction with the Leeu Taaiboschspruit Forum. Such actions may however take some time to be properly implemented and should be evaluated in the medium to long-term.

 

Point 4: The last point in our Catchment, the Vaal Barrage

This is almost the last point within our Catchment. It is clear when comparing the first graph to this graph that the water quality within the Vaal River has deteriorated as a result of the various impacts within our Catchment. The green trend line indicates that EC will continue to increase, and the WQO was exceeded for almost the entire year. The EC is currently just below 75mS/m. Both source and resource directed measures are needed to improve the water quality within the Vaal River. 

 The overall picture indicates that water quality deteriorates significantly within our Catchment. This is due to many impacts including point source pollution, and non-point or diffuse pollution such as run-off from contaminated areas. To improve the water quality within our Catchment the co-operation and dedication of every stakeholder will be required. This includes not only the obvious stakeholders such as industry and mining, but also the Local Municipality, agricultural industry and residents within the Greater Sasolburg area. There is a lot of work to be done, but the Department of Water Affairs and Forestry and the Leeu Taaiboschspruit Forum are up for the challenge!