River deltas are changing shape
Deforestation and damming have altered the shape of river deltas across the globe, contributing to a net 54 square kilometres of land gained per year over the past three decades, according to a study published in the journal Nature.
These landforms are home to hundreds of millions of people, says lead author Jaap Nienhuis, from Utrecht University in The Netherlands. “Think of Bangladesh, Vietnam, Netherlands, New Orleans.”
Throughout human history, deltas have been hubs of trade, transport, farmland and settlement, driving socio-economic development. They are also important environmentally, as they harbour diverse ecosystems.
Deltas are formed by sediments deposited as rivers enter still or slow-moving water, such as oceans, estuaries and lakes, but their sediment supply is affected by waves, tides and rivers, as well as damming and deforestation.
Nienhuis and colleagues developed a model to predict how delta shapes are affected as these factors influence sedimentation.
Natalie Parletta
