It typically ranges from 15 to 18 times the width of the channel. The zone within which a meandering stream periodically shifts its channel is known as a meander belt. The result of this coupled erosion and sedimentation is the formation of a sinuous course as the channel migrates back and forth across the axis of a floodplain. It is produced as a watercourse erodes the sediments of an outer, concave bank ( cut bank) and deposits sediments on an inner, convex bank which is typically a point bar. It is suggested that preservation of individual bars or meanders is affected by the channel pattern, meandering style, river avulsions, and lithology for the Holocene time period.The Jordan River, near the Dead Sea, 1937Ī meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. In this model, drivers of preservation depend on spatiotemporal scale, with each hierarchical level being informed by processes from the levels above and by additional processes at the specified level. Preservation at the scale of accretion packages was dominated by variability or randomness.īecause these results were largely consistent with previous quantitative analyses for other (natural and modelled) meander belts, an updated conceptual model of preservation was proposed. At smaller spatial scales, this effect appeared weaker and was particularly modulated for extensive individual bars. Furthermore, at the meander-belt scale, the Sadler effect was prevalent (□2 > 0.95), which makes the preservation of fluvial sediment packages predominantly depend on their age of deposition. Additionally, preservation and reworking frequency were found to be logarithmically related to each other. In contrast, preservation was more homogeneous for channel patterns without extensive point bar development. It was observed that preservation was generally higher for extensive point bars (with scroll bars) and marginal deposits than for smaller bars and sediment deposited where the dominant channel migrates little over time (>90% versus 0–30%, respectively). Two model runs showed extensive meander formation by a continuous single-thread river (□ ≈ 1.5). Four model scenarios were run with different mean water discharge, which produced channel patterns ranging from barely mobile enough for meandering to highly mobile, or wandering, with multiple threads. This river was analogous to the lower reach of the river Rhine in Germany but downscaled to flume dimensions. A morphodynamic, two-dimensional model (Nays2D) was used to simulate the evolution of a single-thread meandering river that is dominated by chute cutoffs. Here, previously proposed conceptual models of fluvial preservation were evaluated through numerical modelling. ![]() While vertical preservation in a long stratigraphic section is well understood, specific understanding of the forcing mechanisms and robust quantitative metrics of migration and lateral (meander) preservation rates and temporal development still are underdeveloped. Over time, continued channel migration and new cutoffs will erode, rework, and reincorporate parts of the older abandoned meanders. This leaves a cutoff meander element (usually a point bar complex with an oxbow lake) with a certain area and in a certain lateral position. A meandering river tends to shift and sharpen its bends as the outcome of channel migration, and at some point cut them off. ![]() When rivers keep meandering long enough, their channel belts widen to a certain width due to lateral channel migration processes.
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