What's to be dune? Durban's sand is in all the wrong places
uShaka Marine World is battling too much sea sand and too little sea water
Too much sand and too little sea water is causing a major headache for Africa’s biggest marine aquarium as tourists to the popular uShaka Marine World are battling to see its underwater attractions.
The Durban facility – visited by more than 700,000 people a year – has been struggling for nearly two years to get enough salt water to replenish and clean the giant marine display tanks at one of the province’s most popular tourist attractions.uShaka officials say that, while the health of sea animals and fish is not under threat currently, the lack of water means that tanks are murkier than they should be, making it more difficult for visitors to see the fish and sea animals in them.This is because the aquarium needs millions of litres of fresh sea water every day to flush away food remnants and excreta generated by uShaka’s thousands of fish, along with scores of sharks, dolphins, seals and other sea creatures.
To do this, sea water is collected from an underground network of wells below Moyo’s Pier.But now an artificial accumulation of sand in the vicinity of the Point Waterfront means the aquarium’s sea water wells are often left high and dry, especially at low tide.
“We now have situation where there is too much sand on some sections of the beachfront – and too little sand on other beaches that are being washed away,” says Johnny Vassilaros, a Durban businessman and marine sports enthusiast who blames the eThekwini municipality and Transnet for allowing the city’s decades old sand-pumping scheme to fall into disrepair.Although beach erosion happens across the South Africa coastline, the massive piers in front of Durban harbour create a major artificial barrier to the natural movement of sand that helps to replenish eroded beaches. As a result Durban has been compelled to replenish the central beaches on a regular basis using a sand-pumping scheme designed by the Council for Scientific and Industrial Research in the late 1970s.However, when the Durban harbour mouth was widened more than a decade ago, Transnet demolished the city’s sand hopper (storage area) and since then the city has been relying on a temporary sand-pumping scheme that Vassilaros and other residents believe is dysfunctional.“These problems were brought to the city’s attention and, instead of taking responsibility and pledging to rectify the problem, they instead try to offer us weak and lame excuses. Ever since they demolished the old sand-pumping hopper station in 2007, our coastal engineering department has been making one blunder after another, failing dismally in its primary function of replenishing the city’s beaches with sand,” said Vassilaros.
uShaka spokesman Dr Larry Oellermann said: “I can confirm that we are concerned about the degree of sand inundation at uShaka beach. The rising sand level effectively makes the wells deeper than intended, while at the same time pushing back the tide so that the wells are no longer covered by seawater at low tide.“It becomes more difficult to extract sufficient volumes of water from the well-points to maintain uShaka Marine World operations consistently. It also compromises our pumping infrastructure, which has to work beyond design specifications. This in turn increases maintenance costs, such as having to replace damaged parts, re-bed the well-points much more regularly, and increases the overall threat of systems failure.”
He said the SA Association of Marine Biological Research was making every effort to ensure that sufficient fresh seawater was pumped to maintain uShaka’s sea animals in the best of health.“The municipality has pumped sand onto uShaka beach in the past, but this was done in consultation with uShaka Marine World and was suspended when the sand started to become too high. Unfortunately, the volume of sand pumped ashore increased significantly in 2017, and requests to decrease the amount of pumping have not been met with a positive response. We have been informed that there isn't much that can be done about it,” said Oellermann.eThekwini municipality spokesman Thozi Mthethwa said: “We are aware of the restrictions and are sensitive to adverse effects of sand pumping on the (uShaka) intake well points. In view of this we have regular engagement with uShaka Marine World, especially prior to us pumping in that vicinity.
“The amount of sand pumping is kept to a minimum in the vicinity of the intakes and we also endeavour to pump as far north of the intake wells a far as possible. In terms of a long-term solution, the city is investigating options to improve the sea water extraction ability and one of the proposals currently being considered is the extension of the pier into deeper water.”