Wetlands and strategic water sources

Feb 2, 2024 | Uncategorized

How conservation keeps our taps running

Our Kogelberg Biosphere water systems are a delicate web of wetlands, rivers, dams and aquifers. These components are constantly in flux, and interact with one another in complicated ways.

If the 2018 drought taught us anything, it’s that fresh and clean water should not be taken for granted – especially in the age of environmental crisis.

Strategic Water Source Areas (SWSAs) are areas of land that are considered to be of national importance for our water supplies. They either supply a disproportionate quantity of surface water runoff in relation to their size, or they have exceptionally high groundwater recharge. In some cases, they are instrumental in replenishing both surface and groundwater sources.
Studies show that SWSAs only cover about 10% of South Africa’s land, but they provide 50% of our surface water. This, in turn, supports 50% of our economy and 70% of our irrigated agriculture.

The Kogelberg Biosphere is home to a vital SWSA – which is linked to the City of Cape Town (COTC) water supply.

Kogelberg’s many wetlands are inextricably linked to the surrounding dams, rivers and aquifers that form the lifeline of ecosystems and communities alike. So, maintaining clean and healthy water sources is not just imperative from a conservation standpoint, but also from a social one.

The Upper and Lower Steenbras dams, both located inside the Biosphere, directly supply about 10% of the water used by the COTC metropole and surrounding towns. This means that the Mother City is heavily reliant on the health of surrounding ecosystems to keep the taps flowing – especially those based in the Kogelberg.

Seeing as only 11% of all the SWSAs in our country are in protected areas, the preservation, restoration and rehabilitation of these areas are a growing focus for conservationists.

Currently, a growing threat to the health of our water sources is pollution from urban areas due to deficient infrastructure. Waste from outdated water treatment plants – or from informal settlements without proper plumbing and sewage systems – can pollute water bodies through microorganisms. These contaminants end up in our dams or leach into our groundwater sources – the same ones that replenish our reservoirs and keep our taps running.

The state of our SWSAs is directly linked to water quality and availability. If we lose our SWSAs, we lose access to safe freshwater.

There are many more threats to our SWSAs. Land degradation, climate change, large-scale plantations, fire and invasive alien plants are all major concerns. This is why the Kogelberg Biosphere is a member of the steering committee of the Boland-Groot Winterhoek Strategic Water Source Collective – a group working to combat drivers of ecosystem degradation in SWSAs.

Invasive trees in particular each consume hundreds of litres of water a day and are interfering with our natural water cycle, so alien clearing is a big part of the battle to save our water sources.

The Biosphere supports a project managed by the Groenland Water User’s Association to clear invasive species in the Grabouw/Elgin area. The funds to manage the project are donated by British retailers, coordinated by WWF South Africa. Clearing costs are covered by the Western Cape Department of Agriculture’s LandCare division, The Nature Conservancy (TNC) and property owners.

In other invasive alien clearing projects, a WWF South Africa-funded team are working in the Kleinmond Nature Reserve, under the supervision of the Kleimond Nature Conservation Society’s hacking group. And a second team is working on De Draai Farm 563, next to the Rooisand Nature Reserve, funded by the Western Cape Department of Agriculture: LandCare.

Through these kinds of focused action, we can help ensure that more freshwater resources are available for use where and when it is most needed.

Why are our wetlands so important?

Wetlands provides us with free ecosystem services – and yet they continue to be exploited and degraded. In fact, many aspects of human wellbeing are tied to the health of the world’s wetlands.

  • They provide us with clean water. Wetland plants act as filters, slowing down water movement and trapping particles (such as sediment, organic matter and bacteria).
  • Wetlands are also very effective for flood control. Dense stands of wetland plants slow water down and force the water to spread out and therefor reduce the damaging effects of floods.
  • Wetlands often contains deep layers of peat (dead, but not decayed plant material) Peat act as a sponge, taking up water and releasing it slowly after the flood has passed
  • Wetlands and river flood plains (also a type of wetland) form some of the most productive lands on earth, turning more carbon into living tissue than rain forests area for area. Wetlands are therefore important carbon sinks and play an important role in mitigating against climate change.
  • Finally, wetlands provide vital habitat, food and shelter for many animals and plants.

Every wetlands matters – and therefore as Kogelberg Biosphere residents, it’s our responsibility to value and be stewards of our wetlands.



Stuart, H., Watson, K. & Marsh, A. 2023. ‘The Boland-Groot Winterhoek Strategic Water Source Areas Collective: Founding Governance Document’.

Le Maitre, D., Seyler, H., Holland, M., Smith-Adao, L., Nel, J., Maherry, A. & Witthüser, K. 2018. ‘Identification, Delineation and Importance of the Strategic Water Source Areas of South Africa, Lesotho and Swaziland for Surface Water and Groundwater’.


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