THE iSimangaliso Wetland Park on KwaZulu-Natal's North Coast has re-linked the Umfolozi River to the St Lucia lake.
This has restored the functioning of South Africa's largest estuarine system and preserved its natural beauty.
Umfolozi River and St Lucia were deliberately separated for irrigation purposes in 1952, a process that reduced freshwater inflow to the system and interfered with natural mouth dynamics.
These factors, combined with below average rainfall conditions from 2002 to 2010, resulted in the St Lucia estuary mouth remaining closed to the sea for the better part of the past decade.
It also meant that St Lucia had not functioned as an estuary, and inshore line fishing and crustacean fisheries have been impacted.
The park's chief executive Andrew Zaloumis yesterday said the re-linking of the Umfolozi River back to the St Lucia estuarine system is an important first step towards the restoration of estuarine function.
"Our ultimate aim in the restoration of St Lucia lake is to protect iSimangaliso's World Heritage Site without setting up a management regime that includes continuous manipulation. Since the beginning of summer, the Umfolozi has migrated naturally northwards from Maphelane towards St Lucia.
"As winter approached and water flows in the Umfolozi dropped, this migration slowed and the Umfolozi reached to within 300m of the St Lucia mouth. This placed the system in a good position for iSimangaliso to facilitate the linking of the two systems," he said.
To re-link the two bodies of water, iSimangaliso, together with Ezemvelo KZN Wildlife, used a tracked excavator to establish a beach spillway between the two mouths in March.
The spillway was prepared as far west on the beach as possible along a route previously followed by the Umfolozi River where there is a natural slope from the Umfolozi to the St Lucia system.
Zaloumis said the spillway construction was carefully monitored by iSimangaliso project specialists and park ecologists. He said park experts, who had been monitoring the state of the Umfolozi, observed the first closure in May.
"Due to the low level of the sand bar, the mouth opened and closed a few times during high tide events. This movement across the sand bar served to deposit sand and slowly raise its height, eventually creating a more stable closed-mouth condition," said Zaloumis.
It's back to nature
THE iSimangaliso Wetland Park on KwaZulu-Natal's North Coast has re-linked the Umfolozi River to the St Lucia lake.
This has restored the functioning of South Africa's largest estuarine system and preserved its natural beauty.
Umfolozi River and St Lucia were deliberately separated for irrigation purposes in 1952, a process that reduced freshwater inflow to the system and interfered with natural mouth dynamics.
These factors, combined with below average rainfall conditions from 2002 to 2010, resulted in the St Lucia estuary mouth remaining closed to the sea for the better part of the past decade.
It also meant that St Lucia had not functioned as an estuary, and inshore line fishing and crustacean fisheries have been impacted.
The park's chief executive Andrew Zaloumis yesterday said the re-linking of the Umfolozi River back to the St Lucia estuarine system is an important first step towards the restoration of estuarine function.
"Our ultimate aim in the restoration of St Lucia lake is to protect iSimangaliso's World Heritage Site without setting up a management regime that includes continuous manipulation. Since the beginning of summer, the Umfolozi has migrated naturally northwards from Maphelane towards St Lucia.
"As winter approached and water flows in the Umfolozi dropped, this migration slowed and the Umfolozi reached to within 300m of the St Lucia mouth. This placed the system in a good position for iSimangaliso to facilitate the linking of the two systems," he said.
To re-link the two bodies of water, iSimangaliso, together with Ezemvelo KZN Wildlife, used a tracked excavator to establish a beach spillway between the two mouths in March.
The spillway was prepared as far west on the beach as possible along a route previously followed by the Umfolozi River where there is a natural slope from the Umfolozi to the St Lucia system.
Zaloumis said the spillway construction was carefully monitored by iSimangaliso project specialists and park ecologists. He said park experts, who had been monitoring the state of the Umfolozi, observed the first closure in May.
"Due to the low level of the sand bar, the mouth opened and closed a few times during high tide events. This movement across the sand bar served to deposit sand and slowly raise its height, eventually creating a more stable closed-mouth condition," said Zaloumis.
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