Cape Town out of Water by 2012

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 19 June 2010

By 2012 Cape Town will be out of water.  This is not conjecture.

As early as 1995 Professor Bryan Davies, then Head of the fresh Water Research unit at UCT, predicted that Cape Town would be dry by 2013.  Not bad from as far back as that.

Theewaterskloof is the biggest supply dam to Cape Town

Over the six past decades, there has been a drought cycle every six to seven years. The last time Cape Town was in a drought was 2004. I have watched this in Cape Town since 1965 when I can first remember the newspapers reporting the dam levels every day, and this has been the case to a greater or lesser extent for the past forty years.

We have always been able to augment further supply by building an additional dam, but not so anymoreThere is not another single place or any more river water that can possibly be found anywhere in the Western Cape for augmenting supply. The Western Cape is simply dammed out of water.  The rest of the country is in no better condition, so we cannot go looking elsewhere to steal this precious resource.

Two ways of augmenting supply to Cape Town have recently been mooted by the minister of DWA (Department of Water Affairs) Buyelwa Sonjica, viz. the desalination of sea water and pumping water out of the Table Mountain aquifer. Simply put, both of these augmentation systems are not sustainable, and should not and must not be pursued. The former is too energy hungry, and the latter means pumping fossil water from the TM aquifer. Clearly these are not options for a way of finding water for Cape Town.

What is studiously being ignored by Minister Sonjica is our ability to use less water, as well as ways to augment our own supply. Minister Sonjica will not be found encouraging citizens to harvest water; mainly because this would not mean any revenue for her department.

However for this to work, we need a few things to fall into place, which things will happen sooner than later.  These are:

  • The inability of our city council to process sewerage.  This really is the case already with Cape Town City Council only able to process 65% of the effluent running to their sewerage treatment works. The rest of the semi and untreated sewerage runs into rivers etc.
  • The inability of the Department of Water Affairs (the owners of the water in our dams) to meet the increasing demand for water for Cape Town from the rivers in the Western Cape.
  • The inability of the City Council to make our drinking water potable.  In this regard, there are a burgeoning number of municipalities around South Africa who admit that they cannot clean the water in the pipelines to a drinkable standard.  Among other reasons for Cape Town is the growing number of informal settlements in our catchment areas. One only has to look at Hout Bay and the condition of the Disa River – the deadly condition of this water kills every living thing in the river and estuary.  The faecal coli (EC) numbers are 9 billion per 100 millilitres of water.  Unacceptable standards are any number higher than 350 per 100 ml.
  • Realization by Cape Town City that there is simply not enough money budgeted in the near and distant future for sewage treatment.  We need 6 billion Rand right now to upgrade existing and build new sewage treatment works.  There is not more than 300 million (5% of the need) budgeted over the long term budget for the City to use for this purpose.
  • Similarly realization that based on simple arithmetic how much water we will need by 2012.
  • Drought. There is conclusive evidence that the Western Cape is being adversely affected by global warming.  The effect of this can be seen clearly today.  Until thirty years ago the character of winter was that it rained for weeks at a time, cleared up for a day or two, and rained for more weeks.  The rain patterns now see us getting one, two or three days of rain followed by a week or two of warm sunshine.  This means that every time it rains, the first ten or even twenty millimetres of rain are needed just to saturate the soil before any run off occurs.  The total number of millimetres of rain may very well be the same but the way it falls makes an enormous difference.  We simply get less run off these days.

What are we able to do about it?

We can augment our own supply.  We should harvest rainwater for using during the rainy season.

The system for this is the Water Rhapsody Grand Opus, which starts with the Water Rhapsody Rain Runner to harvest water from the whole of a roof.  The harvested rainwater is delivered by an unobtrusive underground pipeline around the building, called a ring main, to water tanks (of which there are a large number of different sizes available). Each Rain Runner from each downpipe tees into the ring main.

Rainwater tanks fill very quickly, but an overflowing rainwater tank is not very romantic, so Water Rhapsody plan cleverly to balance the inflow, volume stored and the amount required in the household.

Stored rainwater is then pumped to the whole household. In practice, the stored rainwater is able to sustain the number of people in an average home / business without any municipal feed for an entire rainfall season, and of course in Cape Town, this is in the winter season.

Capetonians use on average 240 litres per person per day, but by using the WWF award winning Water Rhapsody Systems of Conservation you get to use less water without changing your lifestyle. You will with these systems effectively reduce your daily water use from 240 litres to – at worst 120 litres per day. If you do this, stored rainwater will go much further, getting most householders to be completely “off the grid”. This is certainly true for the rain season, and most of the dry season too.  Getting “off the grid” is something we all aspire to, and if we can use all the systems as made and installed by Water Rhapsody, one gets as close to this magic point as is possible.

What we would have done in effect for DWEA and the Municipality without them appreciating us one bit, is to increase the stored water in the dams by a volume of water that is difficult to imagine. It is not just the stored water in one single filling that increases the volume in total, but the yield (which is the number of times the water tanks may be filled and drawn down), and then of course filled again. Should everyone through their own initiative install such a system to harvest, store, and use rainwater, this will make a total annual difference of more than 200 million kilolitres.

This is an amount that I am unable to imagine so for yours and my benefit I have created some analogies:

The volume of the total yield from all the water tanks (total number of times they are filled and drawn down) is the equivalent of more water than the total volume of the second biggest supply dam to Cape Town.  The biggest supply dam to Cape Town is Theewaterskloof near Villiersdorp which holds when full 480 million kilolitres, but not all that water is available for us to use.

Another analogy (bearing in mind the fact that the average use of water in Cape Town per household is 28 kilolitres per month), is saving a kilolitre or tonne of water per household per day.  Put this water into road water tankers and park them nose to tail, and these trucks would stretch from Cape Town to Johannesburg.  Over a whole season, these tankers would stretch around the world (at the equator nose to tail) ten times!

Yet another analogy is to imagine an Olympic sized swimming pool full of water.  The amount of water saved would fill 1350 of these pools per day.

Emergency supply. Yet another of the advantages of having rainwater tanks is that you create an emergency supply against future water outages.  Water outages are the very next way that our municipality will use to get us to use less water.  By having Water Rhapsody to install water tanks to harvest rainwater, for your benefit they will install an emergency supply fed from the municipality, which guarantees the householder of a continuous supply in spite of outages.

Water Rhapsody will provide something for all seasons.

Jeremy Westgarth-Taylor

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