Meandering Rivers

Summary

Meandering rivers are single sinuous channels, with large winding curves, flowing through low-lying areas of valleys. The flat terrain allows the river to flow more slowly, giving way to the formation of its characteristic wide curves (Boggs, 2014). These curves are typically comprised of two distinct features, the point bar and the cut bank. It's on the point bar where water velocity is slowest, allowing sediments to settle and be deposited. The cut banks are where water velocity is fastest, cause the erosion of the bank sediments. This process of erosion and deposition will cause the river to migrate forward over time. How rivers start to meander is not full understood, but we know it relates to interactions between the water flow and the material which forms the banks and beds (Charlton, 2007). Sediments deposited within meandering rivers vary in size, depending mainly on which side of the river they're deposited. On the outside, where the cut bank forms and flow is fastest, we see coarse-grained sediment with either planar deposition, dune cross-stratification, and trough cross-bedding. On the inside, where point bars form and flow is slowest, we see fine-grained sediments forming current ripples along the shore. (Garde, 2006) As the river migrates over time, these fine-grained sediments will also form either planer lamination or dune cross-stratification (Mason et al., 2019).