Losing Louisiana

Losing Louisiana

Nature Geosci. 2, 488–491 (2009)

The Mississippi Delta is sinking, and to rebuild it

some have proposed diverting the Mississippi River

to carry sediment to coastal areas. But a new study

shows that the delta’s rivers don’t have enough

sediment to counter predicted sea-level rise.

Mike Blum and Harry Roberts, both then

working at Louisiana State University in Baton

Rouge, found that the rivers currently transport

less sediment than the amount that was needed

for delta formation. Sinking land and accelerating

sea-level rise will submerge 10,500–13,500 square

kilometres by 2100, they predict.

Even if sediment trapped in dams was freed, the

duo found, the rivers still couldn’t supply the 18–24

billion tonnes needed to keep the delta above water

until the end of the century.