基于树木年轮的弯曲河流河湾迁移速率估算

针对河流源区缺乏长期的河流监测数据,难以确定河湾迁移速率的问题,通过2016年和2017年2次对黄河源区的实地考察和采样情况,以典型弯曲河流白河的9处河湾为例,根据河湾凸岸淤长与植被演替的关系,利用树木年轮分析判断树龄,依据树木位置和树龄的关系估算弯曲河流河湾迁移速率。估算得出白河9处河湾迁移速率为0.38～6.10 m/a,迁移速率与水流流速、河道比降、凹岸滩高和河谷宽相关,最大迁移速率出现在河湾弯曲度最小的9号河湾。

Estimation of migration rate of meandering river bends based on tree rings

In view of the lack of long-term river monitoring data in river source regions, it is difficult to determine the migration rate of river bends. Through field investigation and sampling in the Yellow River source region in 2016 and 2017, nine river bends of the Baihe River, a typical meandering river, were selected as research examples. The ages of trees were determined by tree rings analysis, and a method for estimating the migration rate of river bends based on the relationship between tree positions and tree ages according to vegetation succession of trees growing on scroll bars in convex bank was used. The migration rates of nine river bends of the Baihe River were estimated to be 0. 38-6. 10 m/a, and the migration rates were found to be related to the flow rate, channel slope, height of the concave bank and width of the river valley. The maximum migration rate appears in the No. 9 river bend where the river curvature is the smallest.