Sunday, March 06, 2011

The St Lucia Estuary Mouth - Dr Taylor Speaks out.

The writer of the letter has been misinformed about the management activities conducted by Ezemvelo and the iSimangaliso Wetland Park Authority. The only time that the conservation authorities have "piled sand across the mouth" was in 2002. The circumstances were that the mouth of St Lucia had closed a couple of months before the wrecking of the "Jolly Rubino" ship near Cape St Lucia. We were warned by the shipping authorities that this ship was carrying extremely toxic chemicals and should this spill the ecological consequences would be disastrous. As a precaution, to prevent any possibility of these chemicals entering St Lucia, we used a bulldozer to push up a low wall of sand on the beach so that overtopping by waves would be avoided. Fortunately the contamination was avoided and over the next month or two the low sand wall was completely dispersed by the wind. Several of the local residents of St Lucia misunderstood what we were doing and continue to perpetuate the myth that we blocked the St Lucia Mouth.

In March 2007 the extreme high seas that were experienced along this coastline breached the St Lucia Mouth. It stayed open after that for six months before closing naturally, and has been closed since then.

St Lucia, like most of our protected environments is affected by what happens beyond the boundaries of the protected area. The main rivers flowing into the estuarine system nowadays carry about 25% less water than when the catchments were undeveloped. This water is lost to irrigation, transpiration losses from plantations and evaporation from farm dams. In addition the Mfolozi Floodplain was canalized and drained in the 1930s for the planting of sugar. The main canal carries the Mfolozi River and its sediments through what was a swampland that had formerly trapped much of the sediment. As a result of this alteration to the natural system, the combined St Lucia–Mfolozi Mouth closed in 1951. To counter this, the Mfolozi River was separated from St Lucia in 1952. This separation of the Mfolozi from St Lucia means that St Lucia is deprived of the Mfolozi water during times of drought. This has had a profound impact on St Lucia and there is currently a World Bank funded initiative to restore (fully or partially) the link between St Lucia and the Mfolozi River.

It must be appreciated that the management of St Lucia is complex and is based on the understanding of how the estuary functions that has been gained from 50 years of scientific research and on the advice given by some of the leading estuarine scientists in the country. St Lucia has been subjected to a very severe drought since early in 2001 and has been pushed to extreme limits during this period.

Dr Ricky Taylor

Regional Ecologist

Ezemvelo KZN Wildlife

9 February 2011

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