泾河流域来沙系数变化与响应分析

Analysis on variation and response of incoming sediment coefficient of the Jinghe River basin

对泾河流域水沙搭配关系、来沙系数及其变化、来沙系数与降雨之间关系、来沙系数与水利水土保持措施年均减沙效益之间关系及其响应等进行了分析。结果表明:泾河张家山水文站年最大洪水的水沙搭配关系为高含沙水流;进入20世纪90年代以后,全流域的水沙搭配关系更不协调。流域3个主要水文站自1988年以来年平均来沙系数均有明显增大的趋势;流域最大洪峰来沙系数和最大日平均来沙系数均与流域最大1日降雨量呈反比例幂函数变化关系;来沙系数随着降雨的增大而减小。流域治理后年均减沙效益和年平均来沙系数关系具有明显的分区规律;两个区单位减沙效益的年平均来沙系数几乎相等;年平均来沙系数对流域水土保持综合治理的响应非常明显。但流域水土保持综合治理对单位减沙效益的年平均来沙系数影响不大。

The water and sediment relationship,incoming sediment coefficient and its change,relationship of incoming sediment coefficient with rainfall, relationship and response of incoming sediment coefficient with annual reducing sediment benefit of water and sediment conservation treatment are analyzed in this paper.The result shows： the water and sediment combination of annual maximum flood at Zhangjiashan hydrology station of the Jinghe River exhibits the character of hyperconentrated flow;the water and sediment relationship of the Jinghe River basin has turned to more inharmonious since 1990s.The average incoming sediment coefficients of three main hydrology stations in this basin have been increasing tendency since 1988.The relationship between the incoming sediment coefficient and the maximum flood peaks and the relation between maximum daily incoming sediment coefficients and the maximum 1-day rainfall are all inverse power function. After the basin being regulated,the relationship of annual sediment reducing benefit with annual incoming sediment coefficient follows the subarea rule apparently.The incoming sediment coefficients of per unit sediment reducing benefit in 2 subarea are all the same.The response of the incoming sediment coefficient to the comprehensive treatment of water and sediment conservation is remarkable.But the comprehensive treatment does not affect the annual incoming sediment coefficient of per unit sediment reducing benefit greatly.