Cape Dams Levels – weekly report (007)
ShowMe Winelands
Cape Dams Levels – weekly report nr. 007
as at 10th December 2018
[Steenbras Upper Dam. Currently 71% full. Photo: DWS]
Thanks to some unseasonal rains in the catchments, net outflows from the main SW Cape dams declined week-on-week to 6.2 M.cuM, 0.7% of capacity, while combined water in the 6 dams fell to 613.5 M.cuM; i.e. from 69.7% to 69.0% of overall capacity. During the same week last year the total volume stored fell by a higher 7.5 M.cuM (0.8%).
Use of water from the dams by the Metro residential and business users also rose fractionally. Consumption by domestic users as well as by business and agriculture is tracking smoothly as the irrigation and tourism seasons gathers momentum.
Here are the levels of the 6 main main dams.
The graph below, which charts weekly water consumption shown by the net change in the water stored collectively in the main dams, reflects a reduction in net outflows as they were offset by rainfall in the catchments last week. This is similar to the sharp bounce that happened in November last year, although the amount of the swing was smaller this time; but very welcome, nonetheless!
[click on the graph to see an enlarged version]Since 1st December 2018, revised level-3 restrictions (105 L/p/d) are in force in the Metro.
Read a summary of the revised Cape Town level-3 water restrictions here.
First indications across November are that, although indeed rising, total consumption has not climbed quite as fast as was anticipated. This trend will show more clearly by the end of December.
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No material rainfall is predicted for several weeks, although an overcast might drop perhaps 2-5 mm of light rain may across the Peninsula on Thursday.
Beware potentially twisted news
Today the Cape Argus reported that the two emergency desalination plants had not been operating. The article by Jason Felix has this sensational title “Two multimillion-rand desalination plants have stopped working”, stating later that they “came at a cost of just more than R250 million each”.
A spokesperson for STOP COCT (a group of them visited the sites and established that the Strandfontein site “was silent and non-operational”) commented that the “wider public feel cheated as they are burdened with extreme water tariffs, but nothing in terms of water security is delivered”.
Now I don’t know if this spokesperson was quoted accurately or whether the newspaper is reporting sensationally but this article conflates unrelated issues and plays with the truth to imply some major catastrophe and failure by Metro management.
So let us understand better what is actually going on – know the facts.
1) Those two small desalination plants at Standfontein and Monwabisi were erected to provide emergency water in the event that ‘Day Zero’ happened. They do not and were never intended to be part of long-term water security. In fact both structures are temporary and scheduled to be disassembled and removed in about 18 months’s time.
2) Seeing that the emergency has passed, they now serve no real purpose other than as a means to test various desalination concepts locally. The City has no investment in the plants and pays for water that they produce only when they supply it. The water supplied by these emergency systems is hellishly expensive, reportedly costing >R40/KL (compared with the <R6.00/KL cost of the dam water supply as it emerges from the City’s purification plants); by far our most expensive water.
3) These two desalination plants, contrary to the implication in the Argus article, are indeed still fully “operational” but indeed did not operate for blocks of some days during November. Reason? There were natural algal blooms in False Bay at those times. When this happens desalination plants are deliberately shut down (this may happen again from time to time) to protect filters but also to prevent potentially harmful water entering and contaminating the whole Metro water system. So this was not a failure but merely a wise operational response to a natural occurrence.
4) Why does City continue to use this expensive desalinated water? Simply, it contracted to accept and pay for extra water for two years as and when produced by these two plants. So when they don’t run for whatever reason, the City saves extra cost. This is not enough to alter the so-called “extreme water tariffs”, but could contribute to a modest saving in some costs by year-end.
At this time Strandfontein is up and running. Monwabisi should be back up by the end of this week.
Draw your own conclusion as to what the reporter and the spokesperson hoped to achieve.
The Eskom crisis continues with failure after failure of electricity generating plants stressing the system. Fortunately Cape Metro installed generators at most pump stations to maintain water delivery even during load shedding, unlike some up-country municipalities where electricity outages are reducing water in reservoirs to dangerous levels. Management interventions do now seem to be helping and Eskom indicates that it may within a few weeks be able to cease load shedding.
To remain fully informed you may like to check the following items weekly
- City of Cape Town weekly “Water Dashboard“, to be found here.
- Our 7-day & 24-hour weather report here shows probable rain in Boland dam catchments.
- SA Weather Services current Synoptic Chart here showing the currently developing weather.
- Look at our supporting current monthly report here.
Tom Brown. Retired international businessman with a background in Finance and IT; and now a fruit farmer, with a passion for the weather and climate. Views expressed in this article, and comments in response, are those of the writer and commenters alone and do not necessarily reflect the views and opinions of ShowMe, nor is any warranty hereby given as to suitability for any purpose of a reviewed enterprise or as to the quality of offered advice, products, services or value. Copyright ShowMe Paarl. All rights reserved. Copy only with prior permission.