Dancing Rivers in the Amazon Basin

The science behind the movements of rivers

contributed by

Photographed by Leo Guerrero © CITA (UTEC)

Introduction

Water, as often said, is a shapeshifting element that constantly adapts itself to fit the forms of its container, but that is only true for sitting water with no movement—no energy. When water moves, however, the body of water that flows at high speed can have so much energy that it can change the shape of its container.

Rivers are great examples. Through time rivers create erosion, deposit sediment, and consequently shift their own shapes as though they can dance. Sometimes they bend further, sometimes they stretch out, and sometimes they split off to form islands and branches. While small movements occur every day, it takes us months, years, decades, or even centuries to notice those changes.

In contrast to the fluidity of rivers, human settlement and built environment are not as free flowing as rivers. Buildings, infrastructures, and riverbanks are often built to last, while rivers always want to move. Thus any interventions made upon rivers, be it to constrain or to ease river flows, rivers will react differently as well. Rivers with strong current can destroy concrete walls, rivers with weak current can later become sitting water, and rivers with high sediment can also create new land masses.

Rivers

In 2017, the Peruvian government has concessioned Consorcio Hidrovías II to develop Hidrovías Amazónicas: a dredging project in the Peruvian Amazon basin which comprises of the Amazon, Marañon, Huallaga and Ucayali rivers. One of the main objectives of this project is to ease the river flow for large ships. For us humans, this could mean that there will be more shipment capacities, more economic opportunities, and less accidents along the waterway. However, dredging the rivers can change river flows, which can further affect the ecosystems within and adjacent to them. Thus, it becomes important for us to learn more about the characteristics of river movements.

We investigated, compiled, and analyzed various parameters from 1987 to 2017 along the four rivers associated with the Hidrovías Amazónicas project. The data will become the baseline which we can compare to in the future after the dredging project or other interventions have taken place.

Click at each of the rivers below to see detail measurements of each river.

Methodology

An important factor which drives our research is the distinction between two river characteristics: meandering and multi-channel (or anabranching) rivers. While both types have common parameters such as river width and sinuosity, each river type also has different characteristics which need to be measured differently.

The Huallaga and the Ucayali are meandering rivers, which can be recognized by their many curves formed by water channels and terrainial slopes (Charlton, 2008). The water channels of meandering rivers often move or migrate over time through the processes of soil erosion on the outer bank and sediment deposition on the inner bank.

In contrast to meandering rivers, multichannel rivers, such as the Amazon and Marañon can be recognized by networks of rivers diverging from and converging back to each other. By diverging and converging, multichannel rivers form stable and vegetated islands along their paths (Taylor, 2002). On many of such islands along the Amazon River, people have built their houses, formed communities, and used the land for agricultural purposes.

Parameters
Learn more...
Analysis Tools
Learn more...

Note:

The methodology, parameters, and tools used for this research are based on the articles by Gutierrez and Abad (2014), Gutierrez et al. (2014), Frias et al. (2015), Mendoza et al. (2016), Vermeulen et al. (2016), Dominguez et al. (in preparation), and Garcia et al. (in submission).

Team

Director of CITA

  • Jorge Darwin Abad

Researchers

  • Luciana Vásquez
  • Gabriela Flores
  • Yulissa Estrada
  • Hernan Chicchon
  • Leo Guerrero
  • Henry Valverde
  • Mishel Meléndez

Data visualization

  • Wan Chantavilasvong