Factors Influencing the Long-Term Stability of the Carbonate Sand Beaches of Mauritius

The long-term stability of the carbonate beaches of Mauritius is the result of the net balance of the supply of carbonate sand from the coral reef environment and the loss of sand to adjacent depositional beaches and through passes in the fringing coral reef to off-reef environments. Carbonate sand is supplied from the lagoon and the balance has been tipped in the favor of losses over supply due to a range of anthropogenic factors including: historic coral harvesting for lime kilns servicing the sugar cane refining industry; removal of coral for water ski lanes; coral health degradation through a decrease in water quality; over-fishing; and creation of navigational passes. This paper presents a technique for quantifying the supply of sand from the various lagoon facies using sediment constituent analysis and hyperspectral imagery. Numerical models are used to describe the sand loss. Non-structural management recommendations are designed to reverse the long-term beach erosion trend.