City of Cape Town Mayor Patricia de Lille recently shared the City’s Critical Water Shortages Disaster Plan with the media.
She also said the City will no longer be relying only on rain water to fill dams, but will look at other non-surface water supplies, such as groundwater abstraction from various aquifers and spring water also.
“As things now stand, if we all use the water left in our dams more sparingly, combined with other demand management measures underway, we can stretch out the number of days of water we have left in our dams to beyond March 2018.”
In terms of the Water Resilience Plan to augment supply with new schemes, the City expects the first water to come online by December 2017/January 2018. Other new sources will come online at various stages and the yield of each source will rise incrementally.
For instance, water from temporary land-based desalination plants in Monwabisi and Strandfontein is expected to come online by February 2018. Thereafter, from March 2018 onwards, additional desalination projects are expected to come online.
In terms of groundwater extraction from the Atlantis and Silwerstroom aquifers, additional water from these projects is expected from about January/February 2018 onwards.
In fact, the City has already managed to increase the production capacity from the Atlantis aquifer as part of the Water Resilience Plan.
It is expected that additional water through water re-use from the Zandvliet Wastewater Treatment Plant will come online from January/February 2018.
The plan to avoid acute water shortages comprises three phases. De Lille emphasised that Phase 2 and 3 can be avoided with progressive savings and rationing in Phase 1.
Phase 1 has already been activated, with water rationing through extreme pressure reduction (throttling).
As water rationing is intensified, some areas will be affected for short periods of time. This will lead to intermittent, localised temporary water supply disruptions.
This process does not result in a complete shutdown of the water reticulation system, but it will severely limit available water supply in the system per day. Water users are asked to store up to five litres of municipal drinking water only for essential usage.
During Phase 2 the City will only keep a certain portion of the system alive, close enough to water collection points. Residents will be able to collect a predefined quantity of drinking water per person per day from these collection sites. During this phase, the City would more actively assume control over the daily water supply available to households and businesses with more extreme rationing.
Law enforcement and policing resources as well as the various resources of intergovernmental partners, such as the Police and Defence Force, will be deployed to ensure that general safety is maintained throughout the city in this phase.
Phase 3 is the extreme disaster phase. and at this point the City would be incapable of drawing water from its surface dams in the Western Cape Water Supply System. There would be a limited period in which the City can continue to supply water before complete water system failure.
Non-surface drinking water supplies will be available for drinking purposes only, and will be distributed to residents through water distribution points.
