基于Q 90法与R2-Cross法的麻栗坝水库下游河道生态流量研究

Study on the Ecological Discharge of the Lower Reaches of the Maliba Reservoir Based on Q 90 Method and R2-Cross Method

针对拟建大型灌区工程从水库引水后可能对水库下游河道造成流量减小及鱼类生态系统破坏等问题,对已建的麻栗坝大型水库下游36.9km的南宛河研究河段采用水文学法的Q 90法与水力学法的R2-Cross法进行生态流量研究。根据两种方法计算结果并取其中最大值作为最终生态流量值,为水利工程建设后生态流量计算和水资源管理提供依据。

In view of the problems that the proposed large-scale irrigation area project may cause flow reduction and fish ecosystem damage to the downstream river channel of the reservoir after water diversion from the reservoir,The ecological discharge of the 36.9km downstream of Maliba Reservoir in the study reach of Nanwan River was studied by the Q 90 method of hydrology and R2-Cross method of hydraulics.Among them,Q 90 method calculated the driest monthly flow in a long series of years under 90%assurance rate,R2-Cross method firstly proposed a hydraulic parameter standard suitable for determining ecological flow in this basin according to the characteristics of river width and target fish body length in this basin,which is used to set the protection standard of river fish habitat.These parameters include water surface width,average water depth,wet cycle rate average velocity.According to the calculation results of the two methods,the maximum value was taken as the final ecological flow value,which provided the basis for ecological flow calculation and water resource management after water conservancy project construction.