Suspended sediments in karst spring waters near Massa (Tuscany), Italy

Abstract.

The marble quarries of the Alpi Apuane supply some of the world's finest ornamental stone. Scanning electron microscopy of sediments emerging from Cartaro Grande, one of the major Apuane springs, reveals that sediments produced by the cutting of the marble are worked through the groundwater system during storm events at concentrations of up to 12,574 mg l^–1. Sediment loads during single storm events reach at least 83 t. The minimum annual sediment load for the 12 months to May 2000 was 300 t. However, due to off-the-scale discharge and turbidity data, this quantity may be as high as 1,000 t, equating to a mean suspended sediment concentration of 80 mg l^–1 and an annual sediment yield of ~100 t km^–2. This remarkably high sediment flux is not surprising given that 440,000 t of marble is removed annually from the Colonnata basin.