We have just hosted the world cup here in Cape town and with the many thousands of visitors here we had to supply drinking water as well as water for washing and showering.
All of the water used in Cape Town can be considered to be new water, not water that has been recycled. Quite a feat if you consider that Cape Town’s population has been growing by at least 50000 people per month and now stands in the region of 4.1 million people.
Travelling abroad today one has to be very careful what you drink and most times one has to revert to bottled water to feel safe. That is not the case in Cape Town as our tap water is amongst the best in the world and can be used for drinking and cooking.
So where does Cape Town get her water?
Way back in 1652 when the Dutch arrived in Cape Town all the water came from streams running off Table Mountain. As the colony grew these streams were dammed by the Dutch and the first reservoir was built where Cape Town’s Golden Acre stands today. If you go into this building you can still see some of the stonework that formed part of this age old reservoir. Until the early 1900′s water in Cape Town was supplied by private enterprise.
As the colony grew the demand for water increased and in the early 1900′s the division of Public Works in Cape Town started taking responsibility for providing water for Cape Town and built the Molteno reservoir on the slopes of Table Mountain. Five dams were also built on the back table of Table Mountain They are the Woodhead, Helly-Hutchinson, De Villiers, Alexandria and Victoria dams and were constructed between 1896 and 1907 and still supply water to the city today.
Even with the reservoir and the dams from 1904 to 1921 water restrictions were placed on the city for up to 15 hours per day in the summer months.
This lack of water obviously could not continue as with the growth of the city more and more pressure was being placed on water supplies. The city had to find other sources of water.
In 1916 a Board of Engineers was appointed to report on a water augmentation scheme for the city.
Their proposal was the Steenbras scheme which would consist of a concrete gravity and arch dam on the Steenbras River. This dam would be connected to the Molteno reservoir through a tunnel in the Hottentots Holland mountains and a 64 kilometre long cast iron pipeline. Work began on the scheme in 1918 and was completed three years later.
The Steenbras scheme could supply Cape Town with up to 42 million litres of water per day although the average consumption was in the region of 29 million litres per day. The consumption however grew rapidly and it was not long before Cape Town once again had a water supply problem. To solve the demand for additional water supplies the Steenbras dam wall was raised and an additional pipeline was laid into the city. This work was completed in 1928.
To provide white water to the city the Constantia Nek, Kloof Nek and Steenbras Water treatment plants were commissioned in 1934, 1938 and 1946 respectively. From then onwards the brown water that was previously supplied to the city became white water.
Cape Town being the popular place it is continued to grow and by 1928 the demand for water was already exceeding the available supplies. The Cape Town authorities built a third pipeline from Steenbras dam to the city and this was completed in 1949. With the added pipeline, pressure was placed on the dam to supply more water so the dam wall was raised again with the work being completed in 1954.
The authorities knew that the Steenbras water scheme would soon be under pressure again so while they were still raising the level of the Steenbras Dam looked around for alternative sources to tap and came across the Wemmers river in the mountains near Franschhoek. In 1953 the Wemmershoek Water Augmentation scheme came into being when the building of a 54 meteres high earth dam on the Wemmers river began. This dam would have a crest length of 518 metres when completed.
Included in the building of the dam was a teatment works which could handle 250 million litres of water a day and an 80 kilometre long 1500/1220 mm diameter prestressed concrete pipeline which would lead to a 264 million litre reservoir built on the Tygerberg above Bellville.
Another augmentation to the supplies happened in 1971 when 66400 million litres were allocated to the city from the Voelvlei dam near Wellington. This augmentation comprised of a 273 million litres per day treatment plant, two pump stations and an 80 kilometre 1500mm prestressed concrete pipeline. Construction on the 570 million litre Plattekloof Reservoir began at the same time and was completed in 1974.
In 1976 another scheme was set in motion whereby water from the Upper Berg, Upper Riviersonderend, Banhoek, Eerste and Wolwekloof rivers were to be linked by tunnels totalling 35 kilometres in length.to the Theewaterskloof dam, and the Stellenboschberg tunnel from which Cape Town receives raw water. Included in this scheme was a 135 million litre per day pre treatment plant at Wemmershoek and a 400million litre per day treatment plant and a 550 million litre service plant at Blackheath and 70 kilometres of 1500mm prestressed concrete pipelines. Construction of this scheme began in 1976 and was completed in 1982.
In March 1994 another augmentation scheme was approved which included a 36 kilometre pipeline to the Faure water treatment plant which was built between 1991 and 1994. A further reservoir of 640 million litres was completed at Faure in 1996. This augmentation supplies water to Khayelitsha, Mitchells Plain and the southern suburbs of Cape Town.
The Palmiet Phase 1 scheme was approved in 1995 and will supply another 31000 million litres of water to Cape town.
In the meantime the Berg River dam at Franschhoek has also been completed and has also come on stream in 2009 supplying even more water to the city.
Cape Town has spent millions of Rand on supplying water to the city and the demand is still rising.
It is our job as responsible citizens of the beautiful city of ours to try and curb water usage so that future generations will be able to enjoy the Western Cape and drink clean water.
If the demand for water continues to rise we might have to start using sewerage water and also start desalinating sea water. Its either that or the cost of water is going to rise so high that we will no longer be able to afford to use tap water any more.
The choice is ours.
LETS START SAVING CAPE TOWN’S WATER.
This article was posted with permission from the author Geoff Fairman from his website Tours in Cape Town