Water engineering was one of the central themes of the crisis and its resolution, playing a critical part both when hard limits were encountered to the scope for emergency supply augmentation and when aggressive pressure management succeeded in achieving dramatic and unprecedented reductions in the city’s daily water usage.
During the crisis the city government developed a large-scale emergency augmentation plan to bring additional water sources on line. This turned out to be unfeasible. Demand management was its only option.
As City of Cape Town Director of Water and Sanitation during the crisis, Peter Flower and his teams were tasked with implementing an emergency build programme. They realised quite soon that the programme was probably unrealistic and unachievable during the envisaged timeframes. He recalls the challenges they encountered that confirmed their initial assessment.
City of Cape Town Chief Resilience Officer Craig Kesson led the Water Resilience Task Team during 2017. He sketches the multiple constraints encountered in the planned implementation of an ambitious 500 megalitre a day emergency augmentation programme.
One of the standout successes of the water crisis period in Cape Town was the pressure management programme undertaken by the city. Barry Wood describes how the existing pressure management programme, already in place when the drought hit, was ramped up aggressively during the crisis, and then rolled out across larger areas, to great effect, with lower pressure in the system reducing water flows through taps and losses from leaks.
Running your business in such a way that a large proportion of your stock is lost or not charged for is not compatible with sound commercial practice or financial viability. Yet this is precisely what many municipalities in South Africa are doing, with non-revenue water rates as high as 41%. Claire Pengelly unpacks the concept.
Countries and cities facing water shortage often resort to intermittent water supply, similar to load shedding or power rationing for electricity. Peter Flower, City of Cape Town Director of Water and Sanitation during the crisis, argues the case against the practice.
How long would it take a 100 million litre a day desalination plant – or a sustained saving of 100 million litres of water per day by a city – to produce the equivalent of 1% of dam capacity delivered by rainfall over a weekend? Dr Gisela Kaiser puts the numbers in perspective.
Successful water re-use projects rely on psychology as much as engineering. Khiyam Fredericks shares insights from his experience implementing such a project at Old Mutual’s Cape Town head office campus.
Basement water in commercial buildings is commonly pumped out and disposed of. It can also be used, says Nardo Snyman.