流域地貌结构因子对径流特征的影响分析

Analyzing the influence of geomorphologic structure factors on runoff characteristics of catchments

  • 摘要: 选取淮河两个主要暴雨中心的11个中小流域为研究对象,分析流域地貌结构因子(流域高程曲线特征值等)对其水文响应特征(多年平均径流系数、流量历时曲线斜率值)的影响.研究发现,流域高程曲线积分值及其斜率对径流特征影响最大.多年平均径流系数、流量历时曲线高流量阶段的斜率值(Sfh)与高程曲线斜率成正比,确定性系数达到0.77和0.67;而流量历时曲线低流量阶段的斜率值(Sfl)与高程曲线积分值也成正相关,确定性系数达0.65.这表明:在地形起伏较大的流域,其蓄水能力较弱,容易造成暴雨洪水过程的陡涨陡落,且多年平均降雨径流系数较大;反之在较为平坦的流域,其径流响应相对缓慢,表现出较强的流域调蓄能力.

     

    Abstract: Geomorphologic structure factors significantly affect hydrological processes. In this study, eleven catchments which located in the main storm center in the Huaihe River basin were adopted as study areas. We analyzed the influence of geomorphologic structural factors (the characteristic values of hypsometric curve, et al.) on the hydrological characteristics. The hydrological characteristics include annual mean runoff coefficient and the slope of the flow duration curve in its upper and lower portions(Sfh and Sfl). The results show that the characters of hypsometric curve (integral value, slope) have greater influence on runoff characteristics than other factors. For example, the coefficient of determination between annual mean runoff coefficient, Sfh and the slope of hypsometric curve is 0.77 and 0.67, respectively, and the coefficient of determination between Sfl and the integral of hypsometric curve is 0.65. They indicate that, the larger the slope of hypsometric curve, the steeper terrain of a catchment, in which it is prone to flash flood and the annual mean runoff coefficient would be larger. On the contrary, the smaller the integral value of hypsometric curve, the flater terrain of a catchment, in which its flood hydrograph tends to become smoother and it has a higher storage capacity.

     

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