Wetlands for disaster risk reduction is the theme for this years’ World Wetlands Day which is celebrated every year on February 2.
Senior environmentalist Philippa Huntly of the Kirstenhof-based Wildlife and Environment Society of South Africa (WESSA), says natural wetland systems are the “earth’s kidneys”.
Wetlands filter pollutants from water that flows through them on the way to lakes, streams, aquifers and oceans.
Wetlands also slow down flooding and ensure steady water flow.
On a walk through Clovelly Wetland on Saturday, author Tim Lundy says before writing his book, Family Walks in Cape Town, he never realised there were so many wetlands in Cape Town.
The book was launched last year at the 16 hectare wetland and bird sanctuary of Intaka Island at Century City.
On Saturday, Tim was leading a walk for winners of a Struik Nature Club competition.
Walking along Silvermine river into Clovelly wetland, he told the group that the low water level is a sign of the times as it is usually flowing.
Tim, who lives in Kenilworth, grew up in Hout Bay and inherited his love of nature and hiking from his dad, Mike Lundy, author of five hiking books.
Clovelly Wetland is managed by the City of Cape Town and River Rovers, volunteers from the Friends of Silvermine Nature Area. The friends groups is a Wessa initiative started in the Western Cape in 1985. Its objective is to involve the public in safeguarding natural resources and working with the owners or managing authorities towards this end. Information on one of the boards illustrates this year’s wetland theme of flood control measures.
The upgrading of the lower Silvermine River began in 1999 when a series of flood detention ponds were created to protect the low lying parts of Fish Hoek from flooding. Dry calcerous dune systems, which are rapidly disappearing due to housing schemes and invasive exotic plants, have been established along the river. They now provide a habitat for tadpoles, toads and birds as well as residents and visitors.
Previous attempts at taming the river include dykes constructed by the railway authorities in 1990 and 1925. Remnants of these can be seen abutting the wetlands.
Tim says parts of the Kakapo wrecked on Noordhoek Beach were used to channel the river as it flowed into the sea. “I’m not sure exactly what parts of the ship were used but they were unsuccessful at the time in trying to control flow and flooding,” he says.
Other wetlands include Glencairn, Soetvlei in Tokai Park, Bergvliet Farm, the Liesbeek and Zeekoevlei.
At Rondevlei and Princessvlei, hippo herds were numerous in the 1960s and these have been re-introduced to Rondevlei, although some have escaped over the years.
Ms Huntly says other important aspects of wetlands is that of storing fresh water, improving water quality, controlling erosion, providing habitat for plants and animals and making floods less severe.
Wetlands also have many direct uses for humans, including harvesting opportunities, recreational space and as a tourism attraction, and they provide a habitat for medicinal plants.
Major threats to wetlands include:
* Being drained for agriculture or the development of buildings or infrastructure, such as roads;
lInvasive alien plants and animals such as water hyacinth, parrot feather and water lettuce; and
* Mining if it disturbs the wetlands to reach deeper lying coal or minerals.
Mayoral committee member for transport and urban development, Brett Heron, says the City’s environmental management department has invited schools to attend a wetlands programme at the various nature reserves during February and March.
These include nature reserves of Wolfgat, Table Bay, False Bay, Zandvlei, Durbanville and Kenilworth Racecourse Conservation Area.
Programmes will vary and will be activity-based but most will include what World Wetlands Day is and the importance of wetlands and water.
“Aquifers are recharged by deep draining of surface water which occurs mainly through rainfall. As most wetlands have impermeable bases, some recharge occurs from the edges of wetlands. Recharge is impeded by catchment hardening (roads, paving, roofs etc.) and removal of vegetation. These activities increase surface runoff and decrease infiltration and the recharging of our aquifers,” said Mr Herron.
* For more information about WESSA contact Philippa Huntly at firstname.lastname@example.org or FOSNA at 021 782 6144.
* World Wetlands Day marks the date of the adoption of the Convention on Wetlands on February 2 1971, in the Iranian city of Ramsar on the shores of the Caspian Sea.