Located at the at the southwestern tip of the Island of Mauritius and just to the east of the Morne Peninsular is one nature’s most fantastic and eye twisting illusions. In both photographs and real life it looks as if a steady flow of water and sand are plunging over the edge of an impossibly deep ocean chasm. Known as the underwater waterfall of Mauritius it is spectacularly beautiful and magical. Unfortunately not all is as it seems.
Mauritius is a volcanic island that emerged from the ocean around 8 million years ago and has eroded away so that it is surround by a fairly narrow underwater shelf and one of the longest coral reefs in the world. Several geological features contribute to the effect. The lagoon is situated between two volcanic peaks – Le Morne Brabant to the west and Mount Laporte and Pilton du Fuge to the East. The Morne Peninsular curves to the East creating a natural lagoon largely enclosed by coral reefs.
A natural gully runs from the base of Pilton du Fuge to the edge of the island shelf some 1.5 km offshore. As it gets closer it becomes wider and deeper creating a natural break in the surrounding reef. It’s been proposed that the water of the lagoon has a higher saline content than the surrounding ocean making it heavier. This denser water drains down the gully aided by currents and wave surges from the east drawing sand with it in a curving pattern that dramatically accentuates the gully and creates the illusion of sandy water pouring over the edge of a chasm.
So it seems that what can be seen in these photos and on Google earth is a trick of the eye. However, as the sand and heavier water reaches the edge of the island shelf it does actually drift down into the magnificent depths kilometres below. The irony is that you can’t actually see it in the images.