Project September 26, 2022

Welcome to the Anthropocene



Inhabitants of the Bailique Islands in the Amazon delta of Brazil in the state of Amapá have adapted to four-meter tides and annual flood water. They live in stilt houses; dig wells only where the water is sweet; and harvest each fish in season. 

But the currents that governed their lives have shifted: turning well water brackish; eroding previously-secure land; and destroying houses, schools, and infrastructure. 

The proximate cause is a replumbing of the Araguari River. It used to flow into the Atlantic, above the Amazon’s mouth. Now it pours directly into the Amazon, alongside the Bailiques, through a waterway called the Uricurituba Channel, that appeared spontaneously.

Rivers running through deltas often meander over geological time. But rarely does one as large as the Araguari, as powerful as the Missouri, change course on a human time-scale. Scientists say three factors reconfigured the Araguari:

  1. Hydroelectric dams on it robbed sediment from the riverbed. Erosion of shorelines were not replenished by new material that would normally hold the river in place.
  2. Buffalo on ranches have trampled soil. The softened ground lets ever-widening rivulets dribble across the alluvial plain.
  3. Tidal movement, most likely enhanced by sea level rise, deepened and widened the channel created from trickling streams, sawing the Uricurituba through the land.