Water Wheel July/August 2022: Estuarine Systems

Abstract

Back in 2009, at the height of a prolonged drought, estuarine scientist Prof Alan Whitfield cautioned that: “Lake St Lucia is like a patient in intensive care. Critical decisions have to be taken now. The only long-term solution is finding a sustainable way of relinking the life-artery of the Mfolozi River with the estuary.” More than a decade later – following some of the most severe flooding in recent memory along the KwaZulu-Natal coastline – so much, and so little, seems to have changed. Whereas the lake all but dried up into a sandy desert landscape during the winter of 2016, St Lucia seemingly has too much freshwater now following the recent severe downpours of rain. There was so much water flowing through adjacent feeder rivers in mid-April that the recently reunited mouths of Lake St Lucia and the Mfolozi River broke open a natural pathway to the sea after another prolonged closure of the estuary mouth. Such seasonal extremes (where there is either “too little” or “too much” freshwater) are common in many river estuaries around the world.

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