Fewer water supply options for Cape Town
13 Jun 2011
The Department of Water Affairs in support of the City of Cape Town is calling on residents of Cape Town to use water more sparingly following the release of the latest Western Cape Water Supply System (WCWSS) Reconciliation Strategy covering the period October 2010 to March 2011. According to the study only a few surface water development options are available for augmenting water supply to the City of Cape Town and surrounding towns. However the department is leading efforts to explore alternatives to ensure sufficient water is available for future use.
Water conservation is however a major component of the strategy to secure sufficient water and therefore the call upon and need for residents to support the City of Cape Town by using water sparingly and to support the city in their aims to reduce water losses and non revenue water. Without the support of the residents the City of Cape Town would not have secure water resources.
Population growth and the subsequent growth in the economy have been identified as major factors that are placing exponential strain on the water available for users of the Western Cape Water Supply System (WCWSS). These users include the City of Cape Town, as well as the municipalities of Stellenbosch, Drakenstein, Swartland and Saldanha as well as agricultural users.
At present the system can safely provide 556 million m3 (cubic meters) per year. The 2010 water requirement on the system was already 511 million m3, (cubic meters) of which 32% was used by the irrigation farmers and 68% by the urban dwellers supplied by the system. According to projections, the remaining 45 million m3 will be fully utilised anywhere between 2017 and 2019 – depending on the growth in the area and the City’s and its residents further successful implementation of its water conservation and water demand management programme.
Cape Town’s water saving initiatives
The City of Cape Town has invested some R60 million in the current financial year in infrastructural upgrades and replacements, water metering, water pressure management among other measures to reduce their water losses and non revenue water. Non Revenue Water is the result of water losses in the distribution system due to pipe bursts or leaks, reservoir overflows, metering inaccuracies and illegal use (theft) of water.
Investment in addressing these factors has had the effect of reducing the average “lost” water, in relation to the water treated and supplied, from 24,4% in February 2010 to 19,9% in February 2011. From these figures, the fruits of this investment are readily apparent in terms of reducing losses.
The Water Conservation/Water Demand Management (WC/WDM) programme includes training caretakers of schools and flats, holding workshops with communities to inform them how important it is to fix and or report leaks (taps, toilets, geysers, etc) immediately and training of teams of plumbers to repair leaks. Communities’ role in securing water through their active involvement in the reduction of water losses and non revenue water in support of their city is crucial.
The city is also planning on going out on tender for a feasibility study of a large‐scale seawater desalination plant within the next month. The study will determine the most appropriate location and size for such a plant.
In addition, the city also plans to do a feasibility study into the large‐scale re‐use of water, the only remaining major potential source of augmenting the area’s water supplies at a lower cost than that of seawater desalination, due to the smaller electricity requirements.
This study will also commence within the next few months. Investigations by the city into the potential for large‐scale ground water development and utilising the Table Mountain Group (TMG) aquifer as a sustainable water resource are also underway. A decision on the implementation of a pilot wellfield development in the TMG will be taken by the city? in the next couple of months.
Studies by the department of water affairs
The two surface water options currently being studied by the Department of Water Affairs (DWA) are the feasibility of pumping winter rainfall runoff water from the Berg River to the Voëlvlei Dam, and diverting winter rainfall water above an agreed threshold from Michell’s Pass (in the Dwars River, Breede catchment area) to the Klein Berg River from where it will be diverted through the existing diversion works into the Voëlvlei Dam. Both these options will make additional water available for use in the WCWSS and by the West Coast District Municipality (DM).
The ecological water requirements downstream of both these schemes are being determined and will be taken into account. The necessary environmental impact assessment process will also be followed for the scheme that is eventually found to be most feasible to implement next to augment the area’s water supplies. The department is also involved in a study to determine the feasibility of augmenting the area’s water supplies through further artificial recharge of the Langebaan Aquifer.
In addition, the eradication of invasive alien plants is becoming increasingly urgent, as the water consumed by such plants can be put to much better use. Each property owner along the rivers feeding into our dams and below the dams must begin to take responsibility for ensuring that their properties are clear of these water‐ thirsty plants.
From the above it is clear that the augmentation of the Western Cape Water Supply System is receiving attention at a high level from all the institutions involved. It is however important to be aware that all these interventions will still take many years to deliver water, and the efficient use of the current supplies including the curbing of water wastage and water losses is of critical importance. All water users in the system are called upon to use their water judiciously in support of the city’s water conservation program.
Peter van Niekerk
Tel: 012 336 8762
Cell: 082 807 4981
Tel: 012 336 8477
Cell: 082 805 9139
Tel: 012 336 8250
Cell: 082 460 4460
Source: Department of Water Affairs
Issued by: Department of Water Affairs
13 Jun 2011
[ Top ]