Sand available to rebuild Mississippi River delta

The lower Mississippi River channel contains a significant reservoir of sand that could help to mitigate land loss at the river mouth, according to a study published online in Nature Geoscience. Upstream dams had previously been thought to be starving the Mississippi river delta of the sediment required to build new land and prevent the drowning of the river delta.

Jeffrey Nittrouer and Enrica Viparelli analysed sediment loads in the lower Mississippi River and found that although the total amount of sediment - both sand and mud - has diminished, the amount of sand has not significantly declined since dam construction. Furthermore, numerical modelling suggests that the amount of sand in the lower Mississippi River channel will decline by less than 20% in the next 600 years.

Assuming that sand is more important than mud for the construction of deltaic land, the study proposes that sand will be readily available in the coming centuries to help prevent the Mississippi River delta from drowning.

doi: 10.1038/ngeo2142

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