Erosion on the shores of the Bailique Archipelago, at the mouth of the Amazon River, has destroyed homes, schools and electricity infrastructure.Without power, this community of fishers and certified sustainable açaí harvesters cannot keep their products refrigerated.Researchers attribute the problem to the choking-off of the Araguari River, located just north of the archipelago and previously known for its tidal bore, when the tide pushed the water upstream, creating dramatic waves.The tidal bore ended in 2013 as the flow of the Araguari was constricted by three hydropower dams built upstream and two canals bleeding its water into the Amazon Basin, allowing the sea to advance over the islands. The Bailique Archipelago is located at the mouth of the Amazon, where the mighty river meets the Atlantic Ocean in the Brazilian state of Amapá. It comprises eight estuarine islands that are home to about 13,000 people, coexisting with the dynamics of the surrounding lowland forest. But the balance between these communities and the environment, where small-scale fishing and sustainable management of açaí palm are the main income sources, has been deeply shaken by progressive erosion and riverbank failure. Known locally as “fallen earth,” such destruction affects homes, schools, power lines, water treatment plants, and the very survival of riverine communities and the ecosystem where they have lived since the 19th century. At the heart of the problem is the Araguari River, which drains just north of the archipelago and was long famed for its tidal bore, known here as pororoca — a phenomenon in which ocean tides push back against the mouth of the river, sending water surging upstream and creating the kind of waves surfers dream of. But the pororoca, once one of the strongest in the world, came to an end in 2013. The mouth of the Araguari had been silting up at an intense rate, and the decline in the flow rate diverted the tidal bore to a secondary river. The story made the headlines, but it was only the first in a series of events that make up one of the worst environmental disasters in the state of Amapá — and one that continues to unfurl. The basin drained by the Araguari covered one-third of the state’s land area, but has now been subsumed into the Amazon basin. A 600-meter (1,970-foot) stretch along the Araguari’s mouth, where the pororoca used to generate massive waves, has been turned into pasture. Now, buffalo ranchers bicker over the land, which is ostensibly state-owned, in an attempt to claim ownership and expand their properties.