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Why does the Indus River sometimes change its course?

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Physical map showing the Indus River basin and its drainage network across parts of Pakistan, India, China, and Afghanistan. The map details river courses, tributaries, canals, dams, irrigated and marsh areas, sand regions, and elevation changes with shaded relief. International, disputed, and control boundaries are marked, and a small locator map in the corner shows the basin's position within South Asia. — Indus River The Indus River basin and its drainage network.

The Indus River frequently changes its course primarily due to the nature of the terrain through which it flows and the impact of heavy flooding. As the river moves slowly across the Indus River plain, it deposits accumulated silt on its bed, which gradually raises the riverbed above the level of the surrounding sandy plains.12

While the river is lined with flood-protecting embankments (bunds) to contain its flow, these structures can give way during periods of heavy flooding, such as those experienced in 1947, 1958, and 2010. Because the riverbed is composed of alluvial sands and clays, it is susceptible to erosion and instability when these floods occur, causing the river to breach its banks and shift its channel. Historical and physiographic evidence confirms that the river has been wandering and shifting its course—generally toward the west—for at least 4,500 years.123