Meandering rivers are abundantly present on earth, from the largest rivers to the smallest tributaries. The classical view of meandering rivers is a sinuous planform with rounded bends, which grow and migrate until they are cut off. However, many meandering rivers do not show lateral migration and have planforms that are much more complex than this classical view. Based on a detailed palaeogeographic study, we find that low-energy meandering rivers may develop complex planforms with sharp bends, while their self-formed deposits increasingly constrain the lateral mobility of the river channel. This finding is confirmed by data of 48 meandering river reaches of varied scale from around the world, which show that erosion-resistant floodplain deposits are preserved in the river banks when the river energy is below a critical threshold. This increases bank stability over time and thus enlarges the required energy needed to break out of the self-constraining tendency. Self-constraining thereby enhances resilience of the system, but highly non-linear increase in bank erosion will occur if river energy exceeds the critical threshold. Our study provides a novel explanation for river planforms and river dynamics and their responses to climatic changes.

These data belong to work in review.