St Lucia Estuary: Rehabilitation in sight
Naturally, the Mfolozi River mouth should join the St Lucia estuary, the two entering the sea together. The last time this was the case, however, was 2002.
AN end to long-term research into the St Lucia estuary system is in sight.
A recent announcement detailing plans of mechanical intervention to encourage the Mfolozi River mouth to join the estuary were met with great applaud.
Estuaries are dynamic entities, continually changing in accordance with the level of interaction with rivers and the ocean.
During dry months the estuary will have less interaction with surrounding bodies of water, the mouth closing for periods. During times of excessive rainfall, interaction will be more evident.
Naturally, the Mfolozi River mouth should join the St Lucia estuary, the two entering the sea together. The last time this was the case, however, was 2002.
Shortly thereafter the two mouths were manually separated, resulting in a closed estuary system.
This situation is far from ideal, as certain fish species that would naturally use the estuary as a nursery during the early stages of their life cycle have been unable to do so.
It is thought the degradation of estuarine nursery areas along the KwaZulu-Natal coast has contributed to the decline in the biomass of species such as the Natal stumpnose which appears on the red list of WWF’s SASSI consumer guide.
Protection imperative
According to the South African Association for Marine Biological Research (SAAMBR), ‘Protection of suitable marine and estuarine habitats is therefore imperative to the future status of this and other estuarine dependents.’
In 2012, the iSimangaliso Wetland Park Authority implemented measures, by means of a spillway, to encourage the nursery status of the estuary. Since then, certain species of fish, prawn and crab have been able to gain entry during times of high rainfall.
However, more drastic measures must be taken to further encourage the system’s rehabilitation. Research has confirmed both the Mfolozi River’s natural path to the estuary and that mechanical excavation is required for this to happen.
The ‘dredge spoil pile’, a 2.6-million cubic metre sand dune, which was formed over time when the estuary was dredged, currently blocks the river’s natural path to the estuary and must be removed before the estuary system can return to its natural state.
Tender documents are in the process of being drawn up and the project will be put out to tender once these are finalised. iSimangaliso envisages work to commence early next year.
Rudi Redinger, Chairman of the St Lucia Ratepayers Association, said, ‘The RPA salutes this decision and is very positive about it.’
