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Steenbras dams

<div class="ExternalClass15C78392056C42C8AE8542A89864188C"><p>The City of Cape Town's Steenbras dams are often fuller than other major dams. We explain why below.</p> </div>

<h2 class="sectHeading">About</h2><p>The Steenbras dams are often surprisingly full, even during a drought, but there are a number of factors to take into consideration.</p> <span> <h2 class="sectHeading">Dam usage</h2></span> <p>Upper Steenbras Dam is not only used for water storage. It forms the upper reservoir for the City’s Steenbras pumped storage scheme, which generates extra electricity during peak demand.</p><p>Upper Steenbras Dam is also linked by canal and pipeline, to Rockview Dam, the upper reservoir of the Palmiet pumped storage scheme operated by <a href="https://www.eskom.co.za/" target="_blank">Eskom<i class="icon link-external"></i></a> and the <a href="https://www.dws.gov.za/" target="_blank">National Department of Water and Sanitation<i class="icon link-external"></i></a>. It receives transfers from the Palmiet River via this scheme.<br></p> <span> <h2 class="sectHeading">Steenbras Hydro Pump Station</h2></span> <p> <br>The 180 megawatt Steenbras Hydro Pump Station (SHPS) consists of four turbines that are used to generate electricity. <br>During peak electricity demand, it channels water from Upper Steenbras to Lower Steenbras, through the turbine generator, to create electricity. </p><p>When electricity usage is low, usually between 23:00 and 07:00, the turbines pump the water back to the Upper Steenbras Dam to be re-used the next day. In this way, SHPS operates like a battery. The amount of electricity that it can generate in one day is limited by the capacity of the lower reservoir.</p><p>The pump station has successfully offset load-shedding in Cape Town during the lower stages, e.g. stages 1 and 2, for most City-supplied residents. If conditions are appropriate, and SHPS has spare capacity, most City customers will likely continue to be protected from stage 1 and 2 of Eskom’s load-shedding.</p><p>Cape Town is the only city in South Africa to own and operate a large pumped hydro-electric scheme.</p> <span> <h2 class="sectHeading">Part of the supply system</h2></span> <p>The Steenbras dams are part of the <a href="https://www.dws.gov.za/iwrp/WC/" target="_blank">Western Cape Supply System (WCWSS)</a><i class="icon link-external"></i> – an integrated system of dams, pump stations, pipelines and tunnels.<br><br> In addition to serving Cape Town, the system supplies water to the Overberg, Boland, West Coast and Swartland areas and it helps to optimise the use of water resources, as water can be transferred between dams and catchment systems.<br><br> The City carefully manages our water supply and currently maximises water stored in Upper Steenbras Dam as it provides for distribution over a wide area. From its elevated location, we can feed either the Faure water treatment plant via the storage dam at Firlands, or the Steenbras water treatment plant via Steenbras Lower Dam.</p> <span> <h2 class="sectHeading">Water amount</h2></span> <p>The ‘Big Six’ dams hold 99,6% of the WCWSS’s capacity, but Upper Steenbras Dam is the smallest of the dams and holds less than 4% of the water in the WCWSS. This is a small amount if you compare it with the amount of water that the largest dam, Theewaterskloof, can hold. When full, Theewaterskloof holds more than half (53,5%) of all the water in the system.</p><p> <strong>The Big Six dams include:</strong></p><ul><li>Berg River </li><li>Steenbras Lower</li><li>Steenbras Upper</li><li>Theewaterskloof</li><li>Voëlvlei</li><li>Wemmershoek</li></ul> <span> <div class="notification with-heading dark-copy pink bg-light-grey"><div class="graphic with-border"> <i class="info toptip"></i> </div><div class="desc"><h4>Top tip</h4><p> <b></b>Find out more on our <a href="https://www.capetown.gov.za/Family%20and%20home/residential-utility-services/residential-water-and-sanitation-services/this-weeks-dam-levels">major dam levels and see our extended weekly water report</a>.</p></div></div></span>

Find out more about the Steenbras dams

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