确定河流生态流量的几种湿周法比较

为比较不同湿周法在计算河流生态流量中的适用性,采用幂函数描述无量纲化的湿周～流量关系,利用曲率法、斜率法及多目标评价法中的线性加权和法、理想点法(尺度系数r分别取1,2,∞)、乘除法等7种方法计算河流生态流量。结果表明:曲率法的结果偏小;斜率法、理想点法(r=1)、线性加权和法的结果相同,且位于各方法的中间;另外3种多目标评价方法得到的河流生态流量大于斜率法等的结果,但湿周的增加比例明显小于流量增加比例。在湿周～流量关系符合幂函数关系时,利用斜率法或理想点法(r=1)、线性加权和法确定河流生态流量的方法是适宜的。

Comparison among several wetted perimeter methods to determine the minimum environmental flows of rivers

To compare the applicability of different wetted perimeter methods for environmental flows of rivers,the power function was employed to express the relationship between dimensionless wetted perimeter and the discharge.The environmental flows of rivers were determined by means of the curvature method(CM),the slope method(SM) and several multi-objective evaluation methods including the weighted sum method(WSM),the ideal point method with different scaling coefficients of 1(IPM1),2(IPM2) and∞(IPM3) and the multiply-divide method(MDM).The results show that the environmental flows of rivers determined by CM are the smallest.Those by SM,IPM1 and WSM are all the same and lie in the middle of all the methods.Those by the other three methods(IPM2,IPM3 and MDM) are the largest;however,the increment of the wetted perimeter is significantly lower than that of the flows.Consequently,SM,IPM1 and WSM are applicable to determine the environmental flows of rivers if the relationship between the wetted perimeter and the discharge obeys the power law.