How Nature Reserves Supply Water to the Cape Metro
Most of the nature reserves managed by CapeNature are in mountainous areas where much of our rain falls. Just eight percent of South Africa’s land produces 50% of its surface water. These high water yield mountainous areas are strategic water resource areas and include the Boland Mountains, Groot Winterhoek and the Cape Peninsula which provide most of the Cape Metro’s needs through streamflow into dams. CapeNature reserves in this area like Hottentots-Holland, Limietberg and Groot Winterhoek, as well as the Table Mountain National Park operated by SANParks, thus play a vital role in water supply.
Major threats to strategic water resource areas
- Invasive plants – wattles, pines, gums and other aliens overwhelm indigenous vegetation, elevate fire risk and use excessive quantities of dry season water flow.
- Too frequent fires – Fires are a natural part of ecosystem functioning and experts recommend that fynbos catchments are burnt every 10-20 years but our planners and reserve managers say that fires are becoming too frequent which results in irreplaceable biodiversity loss and erosion when heavy rain falls on burnt landscapes and washes away topsoil which enters rivers.
- Poor land management – agricultural development and roads in sensitive areas can cause erosion. Streams
often run dry when they enter agricultural areas as all their flow is abstracted which causes temporary or permanent loss of aquatic life.
- Bulldozing of rivers – increases sediment levels and destroys habitat for fishes and other aquatic life
- Pollution of rivers – affects marine ecosystems, wildlife health, and human well-being
The impact of drought
Periods of drought and good rainfall (abundant water supply) are normal in the W Cape and South Africa and nature reserves that are well managed with correct fire intervals, few invasive plants, etc. have the capacity to recover bounce back quickly from drought. However, prolonged and severe drought can have serious consequences including:
- Greatly reduced flows in streams and rivers
- Reduced growth and reproductive success in plants and animals
- Increased risk of fires (veld is dry)
- Death of plants and animals
When visiting protected areas, use water sparingly from the often limited supply but please do come and spent time on our remarkable, beautiful and valuable nature reserves as public financial contributions (entrance fees, accommodation etc.) help us to better manage them for wildlife conservation and for the benefit of all.
* Content adapted from a presentation by Dean Impson, CapeNature Scientist: Freshwater Fishes | Scientific Services