Vaal River water quality: A matter of life...
Literally the heartbeat of South Africa, the Vaal River water system is not only crucial to human life, but to agriculture, industry, aquaculture and an entire aquatic ecosystem.
Senior Golder Associates scientist Priya Moodley says: "Water quality management is a challenge that requires reconciling economic and community benefits with protecting and sustaining the water system. It's a precious resource that needs expert management."
With vast experience across the water systems of South Africa, Golder is currently involved in more than 40 projects that cover the full scope of water management services.
Between 2006 and 2009, one of these projects took Golder's Water Resources Division on a 1 200 km journey from Mpumalanga to the Northern Cape. "We were commissioned by the Department of Water Affairs (DWA) to develop an integrated water quality management plan for the Vaal River system," explains Golder's Principal Water Engineer, Trevor Coleman.
The project involved a variety of tasks, including carrying out a water quality status assessment, evaluating water quality management scenarios, modelling of water quality and the development of a water quality management strategy.
Running across so much of the country meant that high level analyses were required to investigate actions and impacts on the river in each province, in order to find management solutions that are not only technically viable, but economically practical.
"With large industrial zones and mining activities in its path, the water quality of the river deteriorates as it cascades towards the Northern Cape," says Coleman. "Water treatment is costly and it's unfair to expect people at the lower end of the river to bear all the costs. Golder was charged with setting water quality objectives and reaching a compromise where the system must be maintained, but where users continue to benefit from the resource as economically as possible."
The project formed part of a broader water resources study that comprised the water quality study, a reconciliation study and a water conservation and water demand management study. "The stakeholder engagement process for all three studies was run concurrently, with major stakeholders engaged in the process," adds Moodley. "The company determined specific actions that include treatment, the use of water, ongoing audits and regulations to keep the life-blood of South Africa's economy flowing."
Key to the success of the project was to find integrated management options and actions that would allow the system to be managed as a whole, rather than in fragments. "We reviewed the Vaal River main stem and its major tributaries and water quality throughout the system, quantifying impacts on the river. Among the main issues are the salinity of the water and eutrophication and the economic implications thereof for users of the water.
"We had to reach a compromise between system maintenance and user benefits," says Moodley. "The quality of the water is linked to the quantity, so management has to be economically and technically viable. There had to be major stakeholder engagement so that users had a say in the process too."
Coleman notes that eutrophication is the major threat to the water, with discharges from sewage works, industry and agriculture each having a major impact. "There must be a balanced management of the catchment areas to avoid a cumulative impact downstream. We need to keep it at an acceptable level of impact throughout the river's journey."
The scientists say that a study of this magnitude is a massive investment, but that it can only be meaningful if actions are implemented. "These would include water treatment and usage initiatives, ongoing audits and regulations," Moodley says. "The next phase of study is the Maintenance Strategy, where we will identify a strategy committee responsible for implementation."
Golder believes that a phased approach is vital to the success of water management and, while some actions must be taken now, others will be implemented in five years and still others in ten years.
"It's about limiting any further deterioration of the water and reducing the cost of treatment to potable standards," Coleman explains. "It's such a vast expanse of water that it's extremely challenging, but it's also extremely exciting."
Dr Ralph Heath, Associate and Principal Scientist explains that ecological studies look at three specific indicators: fish, macro-invertebrates and riparian vegetation.
"The drivers of these systems are hydrology or movement of the water, the water quality and geomorphology, or the sediment profile. They work together to keep a river healthy. We can tell by the fish, the bugs in the water or the trees that grow on the banks of a river whether the drivers are in balance."
Fascinating and exciting, water quality management is also the key to a healthy population and a vigorous economy – something Golder Associates keeps in mind through every study. "Our company has a tremendous understanding of local water systems and the Vaal in particular," Heath concludes, adding that some Golder staff members have worked on these specific systems for over 30 years.
"Whether government, industry or the mining sector, our experience runs from feasibility to closure, across the full scope of services. Water is a scarce national resource. Water management provides ongoing challenges – and ongoing rewards."
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