湿周法是河流生态需水量计算中使用较为常见的一种水力学方法,通常采用一维的水力分析结果作为计算依据.二维水力模拟能提供更为细致全面的河道水力参数分布,通过对某水电站坝下13.3 km河道进行平面二维水力模拟,对其在湿周法中的应用进行了探讨.采用弗汝德数( Fr)作为浅滩生境划分标准,把浅滩生境较为集中的河段作为湿周法分析的浅滩河段.随后根据平面二维水力模拟结果,给出了浅滩断面相对湿周-流量关系曲线,采用斜率为1的斜率法计算得到了各浅滩断面的生态需水量.结果表明,采用二维水力模拟结果给出的曲线更为合理.%Wetted perimeter method is a common hydraulic method in the determination of ecological flow requirement(EFR) in rivers,which usually takes one-dimensional hydrodynamic simulation results as the calculation basis. As 2D hydrodynamic simulation can obtain the hydraulic parameters more extensively and accurately,the planar 2D hydrodynamic simulation of 13.3-km reach in downstream of a hydropower station was carried out to verify its applicability in weted perimeter method. Taking Froude number(Fr) as a division criterion of habitat classification,the centralized areas of riffle habitats was classified as the rif-fle segment in the wetted perimeter analysis. Based on the results of hydrodynamic simulation,the graphs of relative wetted perim-eter and relative flow at riffle sections were set up,and EFR of each reach was calculated by slope analysis method with curve slope one.
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