Which mechanism causes stream meandering in lowland river systems when cohesive sediment banks are present?

💡 Explanation

When cohesive sediment banks are present, differential bank erosion occurs due to helical flow, because secondary circulation patterns within the stream concentrate erosive forces on outer bends, leading to lateral migration. Therefore meandering results, rather than increased bedload, downstream fining, or channel incision which require increased precipitation, selective sediment transport, or tectonic activity respectively.

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