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

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(S_fh and S_fl). 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, S_fh and the slope of hypsometric curve is 0.77 and 0.67, respectively, and the coefficient of determination between S_fl 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.