罗玉沟流域典型暴雨洪水及其产沙特性

Characteristics of typical rainstorm,flood and sediment yield in Luoyugou Watershed

以罗玉沟流域实测水文泥沙数据和洪水调查资料为基础，分析几场造成极强烈侵蚀的典型特大暴雨的雨、洪、沙特性。结果表明：典型暴雨面雨量离差系数为0．15—0．74，不均匀系数为0．37—0．90，极端降雨比值系数为1．3-188．8，暴雨中心最大10min、最大30min和最大60min降雨量分别占次降雨总量的19％-29％、35％-73％和60％-100％；次暴雨洪量超过年径流量的30％，径流系数0．20—0．49，洪峰流量模数为4．07—9．34m^3／（s·km^2），洪水总历时6—96h，上涨历时15—80min；次洪输沙量超过年输沙量的60％，次洪输沙模数为0．71-1．40万m^3／km^2，最大含沙量高达774kg／m^3，且沙峰多超前于洪峰10—20min，沙量过程线的消退明显滞后于流量过程线，最大含沙量出现时的流量较最大流量偏小40％-50％；历次暴雨的雨、洪、沙特性差异主要受暴雨时空分布特征和下垫面条件控制，水土保持措施具有明显的滞洪减沙效应。

Based on the observed hydrology and sediment data and the flood investigation data in Luoyugou Watershed, the storm-flood-sediment characteristics of several typical torrential rainstorms causing extremely erosion were comprehensively analyzed. The results show that the deviation coefficient values of the area rainfall of the typical torrential rainstorms is 0.15 -0.74, and the coefficient of nonuniformity is 0.37- 0.90, and the ratio coefficient values of the extreme rainfall is 1.3 - 188.8. The maximum 10 min, 30 min and, 60 min precipitation in the heavy rain center area accounted for 19% - 29%, 35% - 73%, and 60% - 100% of the total rainfall; The flood volume of single storm accounted for more than 30% of the annual runoff, the runoff coefficient is 0.20- 0.49, the modulus of maximum flood discharge is 4.07 -9.34 m^3/（s· km^2）, the total duration of flood is 6 - 96 h, the duration of rise is 15 - 80 min, the sediment discharge of single flood accounted for 60% of the annual sediment discharge, the sediment transport modulus of single flood is 7.1 - 14.0 thousands m^3/km^2, the maximum sediment concentration reache 774 kg/m^3, the sediment peak is often 10- 20 min ahead of the flood peak. The regression of the sediment hydrograph obviously lag behind in the flood hydrograph, the runoff with maximum sediment concentration is 40% - 60% less than the maximum runoff. According to the contrast analysis, the difference of the storm-flood-sediment characteristics is mainly controlled by the temporal and spatial distribution characteristic of the torrential rain and the underlying surfaces conditions, and the effect of flood retention and sediment reduction of the soil and water conservation measures is obvious.