The Steenbras Lower Dam was the first major dam that was built after the initial smaller dams on the top of Table Mountain. It was built in the Hottentots-Holland Mountain range near Gordon’s Bay approximately 64km from the Cape Town CBD. It was the major source of water to the Cape Town CBD, which was the main hub of development at the time, and supplied the Molteno Reservoir (in Oranjezicht) which is also still in use. Today the City’s Executive Mayor Geordin Hill-Lewis, Mayoral Committee Member for Water and Sanitation Councillor Zahid Badroodien and the City Manager, Lungelo Mbandazayo unveiled a plaque to celebrate the centenary of the Steenbras Lower Dam as it continues to serve the residents of Cape Town with clean, drinking water.

Interesting facts about Steenbras Dam:

The dam wall was raised twice since its original (1921) construction and now stands at a height of 27,5 m.

The intake tower, valves and 750mm cast iron pipeline are still in their original state, and are just as old as the original dam wall.

There are two Steenbras Dams (Lower and Upper Dams). They have a combined storage volume of 65 290 Ml (1 Ml = 1 000 000 litres).

The Lower Dam is the older dam and was built in 1921, whereas the Upper Dam was built in 1977

The Steenbras Lower Dam has a slightly larger storage capacity of 33 520 Ml whereas the Steenbras Upper Dam has a storage capacity of 31 770 Ml.

In rainy conditions, when the Steenbras Upper Dam is 100% full, the water overflows into the Lower Dam. When the Upper Dam is not full, there is also a connecting pipe (1,22m diameter) with isolation valves from the Upper to Lower Dam, which allows water transfer to take place.

The Steenbras Dams are also part of the electricity pumped storage scheme that provides Cape Town with cost-effective hydro-generated electricity. Residents in City-supplied electricity areas particularly value this during loadshedding, as they can benefit from reduced loadshedding impact.

The Steenbras Lower Dam is the first major dam that was built by the City of Cape Town to meet the growing water demand of the city in the early 1900s. Only a few minor dams situated on top of Table Mountain were built earlier than this, and their capacity was not sufficient any more. Since 1921, it has remained a main supply source to the Strand, Somerset West, Newlands, Molteno and Wynberg reservoirs, which serve certain areas from Gordons Bay in the East, to Wynberg in the South-West and as far North as the CBD.

The Lower and Upper Steenbras dams contribute 7,5% of the total storage capacity of the six major storage dams in the Western Cape Water Supply System that supplies Cape Town. Although other dams may hold more water, the Steenbras dams are important because of their height, which allows for cost-effective gravity flows to the areas which need the water, and the flexibility of the supply network which serves the whole city (to cover for when other parts of the network are closed for maintenance, etc).

‘So much of South Africa’s economic underperformance relates to a failure to invest adequately in essential infrastructure. So marking the 100th anniversary of the construction of the Steenbras dam is a timely reminder to us to not shy away from big, ambitious infrastructure projects that will serve generations of Capetonians to come. Cape Town must always be building and investing to support the growth of the city. So let’s push ourselves to ask: what is the ‘Steenbras’ project of today that will help prepare for what Cape Town will be a century from now? What are we doing now that will be celebrated in 100 years’ time?

‘This celebration is also a reminder of why it is important to be constantly caring for our infrastructure and maintaining it to the highest standards. In next week’s budget, we will allocate an additional R50 million a year to repairs and maintenance.

‘My sincere gratitude to the officials and staff who have ensured this key piece of infrastructure continues to serve us. Water is our most precious resource and we are working hard to conserve it. Looking ahead, the City is significantly ramping up investment in capital projects over the coming years to ensure we continue to provide clean and safe drinking water to residents. This investment will help us build on an efficient and optimal service for the benefit of the public. Today, we acknowledge the valuable contribution that the Steenbras Lower Dam continues to have in our drinking water supply,’ said Cape Town Mayor Geordin Hill-Lewis.

‘Cape Town’s growth and being an economic gateway to Africa would not have been possible if harbouring ships and trade and industry did not have sufficient access to safe drinking water. Effective management and upgrading of our infrastructure over the years have contributed to the City’s progress.

‘At the same time, the City has a responsibility to provide access to areas that are not formalised and are continuously looking at innovative ways on how to manage scarce water resources.

‘This dam will continue to play a contributing role in the Water and Sanitation Directorate’s journey to building future water supply as outlined in the City’s Water Strategy. This Strategy sets the course toward a future in which Cape Town has sufficient, reliable water from diverse sources so that we can be more resilient to the impacts of climate change. This water resilience strategy was developed as a result of the worst drought the City has experienced on record. Hence we see that groundwater from the Table Mountain Group aquifer is now being injected into the Streenbras Upper Dam, as we cannot rely so heavily on our rain-fed dams in the face of a future of uncertain rainfall and climate change. Operations and asset management strategies are being implemented to preserve the Steenbras Dam’s infrastructure for future years. We must continue the effective management of the infrastructure to ensure that it lasts another century,’ said Mayoral Committee Member for Water and Sanitation, Councillor Zahid Badroodien.

Source: City Of Cape Town