Land clearing also increases the amount of sediment pollution.
"The triggering conditions are related to the amount of sediment in the system," he said.
The amount of sediment available is three times greater than it was in 2004.
"We're reducing the amount of sediment that's going into the harbor, and we've planted about 40,000 trees and shrubs," he added.
The amount of sediment in its present delta suggests the structure is a mere 3m years old.
Changes in rain or snowfall patterns can drastically affect the amount of power a dam produces and also the amount of sediment flowing through the river.
They also suggest that the amount of sediment carried to the mouth of the Amazon each year and then dumped offshore should increase over time something actually seen in sediment cores drilled from that area.
The area has accumulated a large amount of sediment from the Palaeozoic to the present.
The amount of sediment displaced by the rains was estimated at 4,456 m3/km2, over four times the yearly average.
"There's a tremendous amount of sediment, and the concentrations are so high that it really is scary," said the lead author, Michael Singer, a researcher for University of St. Andrews in Scotland and University of California, Santa Barbara.
