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30 October 2019
www.thevillagenews.co.za
Of estuaries, lagoons and wetlands By Dr Anina Lee
D
espite the rain we've had over the last few days, South Africa, and especially the Western Cape, is seriously affected by drought brought on by climate change. Fresh water is therefore an extremely precious commodity. Estuaries and lagoons Estuaries are one of the most important features of the South African coastline; they are tranquil areas of high productivity and play a vital role in the life cycles of many plants and animals – especially as a nursery for fish. The Klein River in Hermanus has an estuary, as do the Onrus River, the Bot River, the Kleinmond River and the Uilenkraals River. These water bodies are often referred to as ‘lagoons’. This may be fine for visitors, but in fact they are not lagoons, they are estuaries. So what is the difference? An estuary is where a river meets the sea. Situated at the interface between fresh- and marine waters, estuaries are among the most biologically productive ecosystems in the world and are of great ecological and economic importance. Estuaries form a transition zone, known as an ecotone, between river environments and maritime environments. Estuaries are subject both to marine influences – such as tides, waves, and the influx of saline water – and to riverine influences – such as flows of fresh water and sediment. The mixing of seawater and fresh water provides high levels of nutrients both in the water column and in sediment, making estuaries among the most productive natural habitats in the world. Estuaries are important as the nurs-
eries of the sea. Since their waters are protected from the weather, are rich in nutrients, are generally warmer than in the ocean, and are usually free of large predators, they’re ideal, safe environments in which the larvae and juveniles of many marine species can develop. Many natural estuaries suffer degradation from a variety of factors including: excessive sedimentation from soil erosion, which arises from overgrazing and other poor farming practices; overfishing; drainage and filling of wetlands; excessive nutrients (known as eutrophication) from sewage and animal wastes; chemical pollutants; and damming for water diversion. A lagoon is a shallow body of salt water separated from the deeper sea by a sandbank, coral reef, or similar feature. It is generally not associated with a river and has very little fresh water inflow.
Kleinrivier estuary.
PHOTO: Giorgio Lombardi
Lagoons with little or no interchange with the open ocean, little or no inflow of fresh water, and high evaporation rates, may become highly saline. Lake St Lucia is an example of such a salty lagoon. Wetlands Wetlands were once considered valueless wastelands that needed to be converted to other uses in order to improve their usefulness to people. Many governments, including South Africa's, were still providing farmers with incentives to convert their wetlands for agricultural purposes as recently as the 1970s. It is believed that about 60% of South Africa’s wetlands have already been lost or severely degraded. There was once a beautiful wetland just behind the dunes bordering the grottos at Grotto Beach. This area behind Dutchies is now filled in and used as a picnic spot. Most residents in the 1950s referred to it as the ‘swamp’. It occupied virtually all the space between the coastal dunes, where the road to the beach runs now, and the grottos. As more houses were built on top
A wetland with Wachendorfia of the cliffs above the grottos, the streams feeding the wetland ceased to be clear and became polluted by inadequate sewage management. This introduced pollution into the wetland. An outcry resulted when it was found that the outflow of the ‘swamp’ onto the beach contained harmful bacteria. The municipality reacted, but what followed was probably an over-reaction. The Hermanus News of 10 August 1957 reported: The Hermanus town council has started work on the Grotto Beach improvement scheme, which it is hoped to complete before the summer season commences. The
Kleinmond estuary. road leading down from the Main Road is being widened at the corner, and the rock blasted from the high embankment is being used to fill up a large portion of the marshy vlei behind the beach, and so provide additional parking space, which is very necessary at the height of the holiday season.
area? Filling in a beautiful wetland where indigenous flora and fauna thrived? Draining a ‘swamp’ without understanding that a wetland is in fact the best natural water purifier? Note that destroying a wetland was, in those days, regarded as a “modernisation scheme”.
The council has experienced some opposition from the public, however, in this matter, as some people dislike any modernisation scheme which may distract from the natural beauty of the area.
We now understand that wetlands are our natural assets, providing a range of products, functions and services, free of charge. Despite being high-value ecosystems they make up only a small fraction of the country's land surface. In a changing climate every wetland matters.
Sound familiar? The public opposed to harming the natural beauty of the
Hip hip hooray for 4 Blue Flag beaches For the first time ever, Castle Beach in Pearly Beach, has been awarded Blue Flag beach status joining the three other beaches in the Overstrand Grotto, Hawston and Kleinmond. These beaches have earned Blue Flag status for the upcoming 2019/20 holiday season which opens officially on 1 December 2019. Added to the local Blue Flag portfolio, is pilot status for Onrus Beach. The shark-cage diving boats operated by Marine Dynamics and Great White Shark Tours, as well as the two whale-watching boats operated by Dyer Island Cruises have also earned their Blue Flag status. This year's announcement was made at the V &
A Waterfront in Cape Town last week Thursday. Altogether 45 South African beaches, 9 marinas and 10 sustainable tourism boats were awarded Blue Flags, of which 33 received the title in the Western Cape. An additional 35 beaches across the three provinces have been given pilot status. Full status Blue Flag sites have met the minimum requirements for Blue Flag status in safety, amenities, cleanliness and environmental standards. Pilot sites are recognised for working towards meeting the minimum requirements for full Blue Flag status. In South Africa, the Blue Flag programme is run by WESSA (the Wildlife
and Environment Society of South Africa) in conjunction with participating municipal authorities. Blue Flag status is awarded seasonally, and municipalities must apply annually to renew the status of their beaches.
Overstrand’s Blue Flag co-ordinator Lauren Rainbird (2nd left) and Mayoral Committee member for Community Services, Councillor Grant Cohen (2nd right), in the company of Dr Thommie Burger, CEO of Wessa, and Sarah Ferguson of Breathe Conservation on being handed the Blue Flags soon to be unfurled on four of Overstrand’s beaches.
PHOTO: Rob Fryer
