Water. Desalination + reuse
Issue link: https://fhpublishing.uberflip.com/i/867173
Water. desalination + reuse September 2017 In Site 19 Water levels in Western Cape's six major dams have dropped dramatically in 2017 Stored water is now less than one third of the level three years ago The six major dams represent 99.6 per cent of Western Cape Water Supply Sys- tem total capacity of 898.2 million m3. Since the final 10 per cent of dam water is challenging to use, the available water is 10 per cent less than dam level. '13 '14 '15 '16 '17 infrastructure at sites at Firgrove Coast and Koeberg Power Station. "It has given our competitors some very good ideas and a couple of them are mentioning the same sites," says Callaghan. The approach of introducing several smaller plants could work particularly well from a distribution point of view, because it cuts out the need for additional, expensive works on intake and outfall structures, and connections to the existing water distribution network. "We don't believe that you need a 450,000 m3/d plant in one place, not with our infrastructure and our population spread," says Callaghan. An additional proposed idea intended to introduce flexibility and to keep down costs was the option to redeploy the mobile harbour units at the infrastructure development sites later on, as part of a more permanent supply of desalinated water for the city. The white paper further suggested that first delivery of water could be within nine to 12 weeks of the initial project commitment date. 120 100 80 60 40 20 0 '13 '13 '13 '13 '13 '13 '14 '14 '14 '14 '14 '14 '15 '15 '15 '15 '15 '15 '16 '16 '16 '16 '16 '16 wk to 31 July 2017 wk to 31 July 2017 wk to 31 July 2017 wk to 31 July 2017 wk to 31 July 2017 wk to 31 July 2017 wk to 7 Aug 2017 wk to 7 Aug 2017 wk to 7 Aug 2017 wk to 7 Aug 2017 wk to 7 Aug 2017 wk to 7 Aug 2017 120 100 80 60 40 20 0 120 100 80 60 40 20 0 120 100 80 60 40 20 0 120 100 80 60 40 20 0 120 100 80 60 40 20 0 120 100 80 60 40 20 0 Berg River Water levels have more than halved since 2013 Voelvlei Levels hit 21.9 per cent in August, the lowest of all Theewaterskloof Levels follow the declining trend in Western Cape Steenbras Upper Water levels have held up compared to others Steenbras Lower Levels began a sharp decline in 2015 Wemmershoek Levels have declined most deeply in past 12 months How many days' supply does Cape Town have le ? Commentators have suggested that water supplies could run out in late 2017, considering rates of evaporation as well as usage. Maximum capacity of the major dams 898.2 million m3 Stored capacity at 7 August 29.4 per cent Usable stored capacity 19.4 per cent Volume of usable stored water 174.3 million m3 Current usage rate 632,000 m3/d Number of days' water at current usage rate 257 days Potential run-dry date (excluding evaporation effects) 16 April 2018