Why Do Rivers Meander?

Meandering is a natural consequence of how water and sediment interact in a river channel. When water encounters even a tiny bend, centrifugal force pushes the fastest current toward the outer bank, scouring it and creating a deeper pool (cut bank). The slower water on the inner bank deposits sediment, forming a shallow point bar. This erosion-deposition cycle progressively exaggerates the curve. Over time, meanders migrate downstream and can become so extreme they pinch off, creating oxbow lakes. Albert Einstein published a paper in 1926 explaining the physics: the tea-leaf paradox, where secondary helical flow in a curved channel drives sediment inward. Meandering is so fundamental that even laboratory streams on perfectly uniform surfaces develop sinuous patterns.