河型及其转化的判别

DISCRIMINATION ABOUT CHANNEL PATTERN AND ITS CHANGES

本文分析了影响河型的内外营力,建立了河型与河流能量、河岸不稳定系数、流域形状系数和地壳相对升降强度间的相关关系式。以汉江和黄河下游为例,用水力参数和河床形态指标,判别河型的转化趋势。

There occur many channel patterns in the field, either straight, meandering or braided one,which in fact, reflects the characteristics of its dran-age area, and is resulted in reaction between internal and external agencies. Also, the channel patterns represeant a balance between hydrologic regimes and geographic environments of their drainage areas, Once this balance is lost, and if time span is long enough, the channel pattern change will take place.Therefore, it is an overall consideration of the influence of both internal and external agencies when channel patterns and their changes are studied .According to data analysis, in this paper a correlative equation between channel pattern and factors has been developed as follows:In which, width-depth ratio, T-strength of uplift and subsidence, QJ-stream power, a-coefficient of drainage area configuration, and A -coefficien of bank stability . Taking the Hanjiang River and the Yellow River as case studies, and using hydraulic parameter and channel bed configuration index, the tendency of channel pattern change has been discriminated . As a result, even though a series of recorded data below reservoir is rather short, the tendency is obvious.