Rivers have always fascinated humans, yet one mystery has puzzled scientists for decades: why do some rivers flow as a single channel while others branch into multiple threads?

Geographers at the University of California Santa Barbara may have cracked the code. By analysing satellite images of 84 rivers over 36 years, they found that erosion is the key factor. In single-thread rivers, erosion on one bank balances with deposition on the other, keeping the channel stable. But in multi-thread rivers, erosion far outpaces deposition, causing widening and eventual splitting.

This discovery is especially important for countries like India, home to mighty rivers such as the Ganga and Brahmaputra. These rivers often shift their paths, increasing flood risks for millions of people. The study suggests that instead of forcing rivers into single channels with embankments, nature-based solutions, like restoring floodplains and building wetlands, can reduce long-term risks and costs.

In short, rivers are not just flowing water; they are living systems shaped by balance or imbalance between erosion and deposition. Understanding this could change how we manage floods and protect river ecosystems worldwide.