Adjustment of self‐formed bankfull channel geometry of meandering rivers: modelling study
Adjustment of self‐formed bankfull channel geometry of meandering rivers: modelling study
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曲流河流自成满岸河道几何形状的调整：模型研究
DOI：
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发表时间：
2020
影响因子：
3.3
通讯作者：
G. Parker
中科院分区：
文献类型：
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作者：
K. Naito;G. Parker
我们考虑了沙床曲流河流水力几何的演变。研究了河道纵向剖面调整时间尺度与河道宽度和深度调整时间尺度的差异。研究了水文环境变化对河岸河道几何形态演变的影响。为了实现这一目标，我们使用了先前开发的河堤河道特征时空共同演化模型，包括河堤流量、河堤宽度、河堤深度和河堤下游河床坡度。在我们的建模框架中，流动可变性是根据特定的流动持续时间曲线来考虑的。利用这一独特的特性，我们确定了在指定的流量持续时间曲线内负责长期河岸通道变化的流量范围。也就是说，研究了极高的短持续时间流与中等高的长持续时间流的相对重要性。明尼苏达河，MN，美国，一个积极蜿蜒的沙床流，被选为一个案例研究。自末次冰期结束以来，研究河段的纵剖面一直在向平衡方向调整，而在过去几十年里，由于水文状况的变化，研究河段的河岸横截面正在迅速扩大。我们使用该模型证明，由于横向通道移动，纵向通道剖面调整的时间尺度远大于横截面剖面调整的时间尺度。我们还表明，水文制度的变化是最近明尼苏达河迅速拓宽的原因。我们的分析表明，在最近的河岸河道扩张中，5-25%的超限流量的增加比0.1%或90%的超限流量的增加更重要。©2020 John Wiley & Sons, Ltd
We consider the evolution of the hydraulic geometry of sand‐bed meandering rivers. We study the difference between the timescale of longitudinal river profile adjustment and that of channel width and depth adjustment. We also study the effect of hydrological regime alteration on the evolution of bankfull channel geometry. To achieve this, a previously developed model for the spatiotemporal co‐evolution of bankfull channel characteristics, including bankfull discharge, bankfull width, bankfull depth and down‐channel bed slope, is used. In our modelling framework, flow variability is considered in terms of a specified flow duration curve. Taking advantage of this unique feature, we identify the flow range responsible for long‐term bankfull channel change within the specified flow duration curve. That is, the relative importance of extremely high short‐duration flows compared to moderately high longer duration flows is examined. The Minnesota River, MN, USA, an actively meandering sand‐bed stream, is selected for a case study. The longitudinal profile of the study reach has been in adjustment toward equilibrium since the end of the last glaciation, while its bankfull cross‐section is rapidly widening due to hydrological regime change in the last several decades. We use the model to demonstrate that the timescale for longitudinal channel profile adjustment is much greater than the timescale for cross‐sectional profile adjustment due to a lateral channel shift. We also show that hydrological regime shift is responsible for the recent rapid widening of the Minnesota River. Our analysis suggests that increases in the 5–25% exceedance flows play a more significant role in recent bankfull channel enlargement of the Minnesota River than increase in either the 0.1% exceedance flow or the 90% exceedance flow. © 2020 John Wiley & Sons, Ltd.
影响因子：
5.4
作者：
K. Gran;Christine L. Dolph;Anna Baker;M. Bevis;Se Jong Cho;J. Czuba;B. Dalzell;M. Danesh‐Yazdi;Amy T. Hansen;S. Kelly;Z. Lang;Jon Schwenk;P. Belmont;J. C. Finlay;Praveen Kumar;S. Rabotyagov;G. Roehrig;P. Wilcock;E. Foufoula‐Georgiou
通讯作者：
K. Gran;Christine L. Dolph;Anna Baker;M. Bevis;Se Jong Cho;J. Czuba;B. Dalzell;M. Danesh‐Yazdi;Amy T. Hansen;S. Kelly;Z. Lang;Jon Schwenk;P. Belmont;J. C. Finlay;Praveen Kumar;S. Rabotyagov;G. Roehrig;P. Wilcock;E. Foufoula‐Georgiou