Media Release: Post the Kiani Satu: Swartvlei Estuary
09 September 2013
SANParks scientists caution that the successful re-opening of the Swartvlei estuary mouth at this time, and restoration of the channel to exactly the same dimensions as prior to the artificial closure, is improbable. Dr Ian Russell says the estuary is currently just above 1 meter above mean sea level (amsl), and the resulting lack of any head of water in the estuary significantly reduces the probability of a successful breaching.’ He adds that the suggestion that Swartvlei Estuary will undergo significant damage if it were to remain closed now and only breach again when the water level reaches 2 meters amsl, is unfounded.
‘This is a naturally open/closed system where such variability in mouth state and water height is natural. In fact these extremes have been significantly suppressed by man’s alteration of the system. If the estuary were to remain closed now, and for a period forward, then yes recruitment opportunities for marine fish and some estuarine invertebrates could be temporarily altered’ he says.
Along the approximately 110 kilometres of coastline incorporated in the SANParks conservation areas there are two estuarine lake systems (Touw system and Swartvlei system) into which seven rivers drain . A further 24 rivers drain this coastline, several of which flow into estuaries such as Knysna, Salt and Groot (West). An estuary can be defined as a partially enclosed coastal body of water, which is either permanently or periodically open to the sea, and within which there is a mixture of seawater and freshwater. Other definitions recognise that these systems can be ‘either continuously or periodically open to the sea, and extend as far as the upper limit of tidal action.’ During floods an estuary can become a river mouth with no seawater entering the formerly estuarine area or when there is little or no river input an estuary can be isolated from the sea by a sandbar and become a lagoon or lake which may become fresh or hypersaline.
Swartvlei has an abundance of fish and birds. During this SA National Parks Week (09- 13 September 2013), come and identify common birds in that area such as Red-knobbed Coot, Little Grebe, Cape Shoveler, Yellow-billed Duck and Reed Cormorant and others.
South African National Parks (SANParks) Corporate Communications
Tel: 044 302 5633
Communications Manager: Garden Route National Park
Tel: 044 302 5633; Cell: 078 702 9663