李志威, 秦小华, 方春明. 天然河湾几何形态统计分析[J]. 水科学进展, 2011, 22(5): 638-644.
引用本文: 李志威, 秦小华, 方春明. 天然河湾几何形态统计分析[J]. 水科学进展, 2011, 22(5): 638-644.
LI Zhi-wei, QIN Xiao-hua, FANG Chun-ming. Statistical analysis of the geometrical form of natural rivers meanders[J]. Advances in Water Science, 2011, 22(5): 638-644.
Citation: LI Zhi-wei, QIN Xiao-hua, FANG Chun-ming. Statistical analysis of the geometrical form of natural rivers meanders[J]. Advances in Water Science, 2011, 22(5): 638-644.

天然河湾几何形态统计分析

Statistical analysis of the geometrical form of natural rivers meanders

  • 摘要: 天然河湾是弯曲河流重要的地貌组成单元,研究河湾的几何形态和演变规律具有较高的理论价值。运用Google Earth卫星图像和AutoCAD软件相结合的方法,选取不同区域的8条河流的136个山区河湾和325个冲积河湾作为统计样本,定义和测量河湾几何形态参数。统计分析表明,山区河湾弯曲度变化区间为1.7,14.8,冲积河湾弯曲度变化区间为1.6,38.5。冲积河湾的弯曲度均值和标准方差都大于山区河湾。山区河湾的弯顶偏向角无明显的趋向性,弯顶向上游发育和向下游发育的机率基本是相同的。冲积河湾的弯顶偏向角大于85°的河湾占65.5%,表明大多数冲积河湾的弯顶是偏向上游发育的。冲积河湾平均河宽与弯顶河宽成较好的线性关系,平均河宽与颈口宽度具有一定程度的正相关关系。天然河湾的横向相对偏移度与弯曲度成较好的线性关系,两者表征河湾平面弯曲形态具有一致性。

     

    Abstract: The river meander is an important geomorphologic component of meandering rivers. Study of the evolution of geometrical form and channel migration of river meanders possesses high academic values. Using an integrated platform of Google Earth satellite images and AutoCAD software, a total of 136 mountain meanders and 325 alluvial meanders in eight rivers from different areas are chosen as statistical samples to define and measure geomorphologic parameters of the samples. The statistical result shows that the meander radius of curvatures in mountainous rivers is in the interval 1.7, 14.8, and the value of the curvature radius for alluvial rivers is 1.6, 38.5. Statistically, the mean value and standard deviation of the curvature radius in alluvial rivers are much greater than those in mountainous rivers. There is not obvious skew angle tendency at bend apex in mountainous rivers, showing almost equal opportunity for both upstream and downstream development of bend apex. The number of meanders with 85 degree skew angle and greater in alluvial rivers can account for 65.5% of the total river meanders, indicating a tendency for bend apexes to grow in the upstream direction. There is a good liner relationship between the average width and the width of bend apex in alluvial rivers. A certain extent of positive correlation is found between the average river width and the meander neck width. The relationship between the relative transverse skewness and the curvature appears is also linear. These characters manifest the consistency of the shape of a planer cure in river meanders.

     

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