| The natural geomorphology of rivers has been stressed and destroyed to different degrees in the development of human beings.This paper selects the natural meandering Chishui River as the research object,and calculates the index values through satellite images provided by Google Earth and ArcGIS spatial analysis technology.Statistics,using MIKE21 and SPSS and quantitative analysis to characterize the planar shape of the landform features.Establish a multi-scale geomorphic feature analysis index system to analyze the fractal features of geomorphic features at the overall reach scale,the correlation between geomorphic parameters at the local reach scale,and the distribution of typical geomorphic units at the geomorphic unit scale,and provide geomorphic feature parameters for the development of river ecological restoration programs.The characteristic parameters are of great significance for revealing the development mechanism of river winding morphology and the development law of landform morphology.The main research contents and results of this paper are as follows:(1)125 curved river sections are selected in the main stream of Chishui River.From three research scales of overall river section,local river section and geomorphic unit,10 indicators such as information dimension,tortuosity,and meandering waveform wavelength are selected.Google Earth and ArcGIS measured and calculated the above-mentioned index values,statistically analyzed the change law of each index,and analyzed the correlation between the indexes.It was found that the development of the Chishui River has a strong symmetry,and the changes of the index values reflect the characteristics of the Chishui River.Topography.(2)Analyze the fractal characteristics of the plane shape of the curved river section at the overall river section scale,and use the information dimension as the overall river section-scale landform feature index to measure the waterline information dimension and the water river bed landform area information dimension,and analyze the correlation It is found that the correlation coefficient between the curvature rate and the waterline information dimension in the downstream reaches peaks at 0.644,so compared to the curvature rate,the fractal dimension is more suitable for representing the fractal geometric features of the river with complex shapes and rich details.(3)Measure the information dimension based on the grid covering method,and use the "instability" phenomenon of the rough calculation value as the criterion to identify the one-dimensional line fractal and the two-dimensional surface fractal unsealed interval.The obtained interval is[10,40],it has been verified that the scale-free interval is effective,and a method for identifying the scale-free interval is proposed.And by analyzing the changing law of the information dimension of the river bottom contour,the method of measuring the fractal dimension of multi-dimensional space is discussed.(4)Based on the development of the Chishui River system,the empirical relationship between the meandering waveform wavelength of the curved river section,the width of the river flat beach,the radius of curvature and the length of the half-wave curved arc and the width of the flat beach of the river are used to calculate the channel coefficient value of the main stream of the Chishui River Scope,the main fluctuation interval of coefficient k1 is[13.18,20.4],the main fluctuation interval of coefficient k2 is[3.0,5.7],and the main fluctuation interval of coefficient k3 is[13.8,23.5].(5)At the scale of the geomorphic unit,by constructing the MIKE21 hydrodynamic model to simulate the flow velocity and water depth of the typical river downstream of the Chishui River,to analyze the distribution of typical geomorphic units and their influence on hydraulic elements,and discover diversified geomorphology The shape has an obvious regulatory effect on the flow of water.. |
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