Global Hydroclimatic Controls on Multithread River Dynamics

Journal article

Plain Language Summary: Earth's largest rivers typically split flow into many interconnected pathways, called threads. Multithread rivers change their planform shape in response to variations in water flow and sediment delivery. However, studying these rivers has been difficult due to limited long‐term observations and analytical tools to accurately characterize their evolution. We analyzed 38 years of satellite images alongside river flow data from 97 multithread rivers worldwide. We found that increased dimensionless discharge values—defined as the ratio of long‐term average discharge to bankfull capacity of a river to carry flow—are associated with an increase in the number of active threads, emergence of one or more threads that carry majority of flow, and a slowdown of river evolution. This result highlights that flow variability, when viewed through the lens of channel morphology, is the dominant control on multithread river dynamics. We also find that multithread rivers in cold climates evolve more slowly compared to their counterparts in other climate zones likely due to the influence of permafrost. With climate change increasing flow variability, we predict that multithread rivers will increase their thread count and become more dynamic globally, potentially impacting livelihoods and ecosystems in river corridors.

Authors: Zhao, F; Ganti, V; Chadwick, A; Greenberg, E; McLeod, J

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: AGU Advances
• Volume: 7
• Issue: 2
• Article number: e2025AV002166
• Publication date: 2026-03-13
• Acceptance date: 2026-02-09
• DOI: 10.1029/2025av002166
• EISSN: 2576604X
• ISSN: 2576604X
• Language: English
• Keywords: sedimentation; river mobility; river planform; lateral migration