Tuesday, May 20, 2008


May 19, 2008



Dave Savides

IN a critical move aimed at decreasing salinity in the Lake St Lucia system, authorities are preparing a team of bulldozers to seal off the Umfolozi River mouth from the ocean.
CEO of the iSimangaliso Wetland Park Authority, Andrew Zaloumis, explained the decision on Sunday:
'Every eight to 10 years our region suffers from drought.
'The ongoing drought, probably the worst in living memory, continues to illustrate that the Lake St Lucia system's long-term survival is linked to the inflow of fresh water from the Umfolozi River.
'The iSimangaliso Authority with its conservation partners Ezemvelo KZN Wildlife are taking both short and medium-term steps to redress this situation,' said Zaloumis.
'In the short term the Umfolozi mouth is being closed so that fresh water with low sediment loads flows via the back channel into the estuary to mitigate increasing salinities in the narrows and lake.
'In the medium term and in order to be prepared for the next drought, the iSimangaliso Authority has signed a Global Environmental Facility (GEF) contract with the World Bank to find permanent solutions to the problem of water supply.
'It is hoped that this will be in place before the next drought cycle.'

Under pressure
'The system is currently in the grip of a long and severe drought, and in March 2007 a rare combination of heavy swells (from Cyclone Gamede), and a very high Spring tide, caused the mouth to open.
'It remained open for 175 days, during which time sea water flowed into the Lake.
'Following this breach, the water level of the Lake increased greatly, and by the time the mouth closed again in August 2007, salinities had reached 30 ppt.
'Ongoing below-average rainfall since then caused many parts of the Lake to record salinities in excess of that of sea water (35 ppt),' said Zaloumis.
'Many species will not be able to tolerate ongoing salinity increases.
'This is worrying, because the large influx of sea water following Cyclone Gamede means that the system is now particularly sensitive to reduced fresh water inputs.
'If we do not receive good rains in Spring (August) then the health of the system could rapidly deteriorate.
'Nonetheless, the Lake appears to still harbour diverse and healthy fish populations, and birds remain abundant throughout the system, which is being closely monitored by iSimangaliso and Ezemvelo KZN Wildlife managers and ecologists.'

While in the past authorities were accused of 'interfering with nature' by controversially preventing the mouth from opening, this time local sentiment appears to be in agreement with the new plan.
'Closing the mouth will no doubt lift the water table and bring in fresh water, which is welcomed,' said tour operator Riette Bennett.
'However, the Umfolozi River brings in lots of mud and silt in the long term and this will obviously be taken into future planning.'

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