MULTITEMPORAL ANALYSIS OF BANKLINE CHANGE AT THE CONFLUENCE OF THE AMAZON AND TAPAJÓS RIVERS USING GEOSPATIAL TOOLS

Authors

DOI:

https://doi.org/10.4215/rm2025.e24007

Keywords:

Lower Amazon, Landslides, Bankline, Raised land, DSAS

Abstract

At the confluence of the Amazon and Tapajós rivers (Santarém), significant changes occur in the bed geomorphology, caused by fluvial dynamics that intensify the phenomena of erosion/retreat ( ̈terras caídas ̈) and/or accretion ( ̈terras acrescidas ̈). The Bankline (BL) is a geomorphological feature subject to topographical changes, which may occur over time, depending on the occurrence of high-energy, neotectonic or anthropic events. The position of the BL is an indicator of fluvial dynamics, whose position varies in time and space, producing movement towards the inner part of the lands (erosion); or towards the water (accretion) and the absence of recorded displacement suggests stability. This article analyzes the multitemporal variation (1995 to 2021) of the BL at the confluence of the Amazon and Tapajós rivers (Santarém), using the Digital Shoreline Analysis System (DSAS) and bathymetric methods. The results demonstrate that on the margins of the Tapajós River, the dynamics are different: on the left, erosion predominates with 91.38 % and on the right; accretion is very high with 74.35 %. In sectors I and II of the Amazon River, both margins are affected by erosion, respectively 60 % and 80 %. The average BL rates were -102.02 in the NSM, -3.91 in the EPR, and -4.42 in the LRR. Mean BL rates were -102.02 in NSM, -3.91 in EPR, and -4.42 in LRR.

Keywords: Lower Amazon; Landslides; Bankline; Raised land; DSAS.

Author Biographies

  • Rafaele da Silva Sampaio, Federal University of Pará, Belém (PA), Brazil

    Master's degree in Oceanography (2023) from the Federal University of Pará. Member of the research group of the Faculty of Geography EGC - Coastal Geographic Studies Group. Member of the research group of the Faculty of Oceanography GEMC - Marine and Coastal Studies Group. She is currently a PhD student in Socioenvironmental Development in the Postgraduate Program in Sustainable Development of the Humid Tropics, belonging to the Center for High Amazonian Studies of the Federal University of Pará. She conducts research in the area of ​​Coastal Geomorphology, Coastal Dynamics, Remote Sensing and Geoprocessing.

  • Maamar El-Robrini, Federal University of Pará, Belém (PA), Brazil

    PhD in Marine Geology - Université de la Sorbonne Paris IV/ Paris IV (1986). He is currently a Full Professor at the Federal University of Pará, Vice-Dean of the Faculty of Oceanography, and teaches undergraduate courses (Faculties of Geology, Naval Engineering and Oceanography) and graduate courses (Naval Engineering, Oceanography and Water Resources). He coordinates the Coastal Marine Studies Group (GEMC/CNPQ) and the Oceanic Geology Laboratory (LAGEOC). He has experience in the areas of Oceanography, Marine Geology/Geophysics, and works in the following areas: Amazon Coastal Zone, Brazilian Economic and Exclusive Zone, Equatorial and Mediterranean Continental Margin. He participated in LEPLAC III and IV, AMASSEDS, JOPS, and PROARQUIPÉLAGO. Coordinated the REVIZEE Program, REMPLAC, Adaptation to Sea Level Rise in the Amazon Delta Project. Currently: National Institute of Ocean Energies (INEOF - Managing Member), Project Coordinator: Sedimentation of the Equatorial Continental Slope, Instability of the Seabed (Mediterranean Sea), River/Oceanic Edges.

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Published

2025-05-26

Issue

Vol. 24 (2025)

Section

Artigos

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