Sediments deposited in the Mississippi delta cannot keep up with regional sea-level rise, suggests a study published online in Nature Geoscience. The researchers propose that the imbalance makes the submergence of the delta inevitable.
Michael Blum and Harry Roberts examined rates of sediment deposition in the Mississippi delta over the past 12,000 years and found that the Mississippi carried substantially more sediments before dam building started. They estimated that 18-24 billion tons of sediment would be required by 2100 to sustain the existing surface area of the Mississippi delta as sea levels rise. This exceeds current supply in the Mississippi river.
The researchers suggest that without an increase in sediment load, 10,000 to 13,500 square kilometres of deltaic land will be lost by 2100.