The construction of check dams in northwestern China has resulted in nonstationary changes in flood peak discharge series; the stationary assumption of the conventional hydrological frequency analysis is no longer satisfied. According to the characteristics of the construction and operation of check dams, the nonstationarity of flood peak discharge series are largely induced by changes in the effective runoff generation area (i.e., the basin area minus the area controlled by check dams). Knowing the power function relationship between the flood peak discharge and the basin area, we can remove the influence of the effective runoff generation area and convert the original nonstationary series into a stationary series. This de-nonstationarity method can achieve stationarity in the first and second moments simultaneously. Therefore, we can calculate the design value of the reconstructed series using the conventional frequency analysis method. According to the effective runoff generation area under design conditions, we can then obtain the corresponding design flood of the original series. We applied this method to the Mahuyu River basin to obtain the design flood under nonstationarity. Due to the consideration of the deterministic influence of check dams during the de-nonstationarity process, the uncertainty analyzed by the bootstrap method is obviously small.

中文翻译：

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从洪峰流量序列中去除非平稳性估计止水坝影响下的设计洪水

西北地区拦河坝建设导致洪峰流量序列非平稳变化；不再满足常规水文频率分析的平稳假设。根据闸坝建设和运行的特点，洪峰流量序列的非平稳性主要是由有效产流面积（即流域面积减去闸坝控制面积）的变化引起的。知道洪峰流量与流域面积的幂函数关系，就可以去除有效产流面积的影响，将原来的非平稳序列转化为平稳序列。这种去非平稳性方法可以同时实现一阶和二阶矩的平稳性。所以，我们可以使用常规的频率分析方法计算重构序列的设计值。根据设计条件下的有效产流面积，可以得到原系列相应的设计洪水。我们将这种方法应用于玛湖峪流域，得到非平稳条件下的设计洪水。由于在去非平稳过程中考虑了闸坝的确定性影响，bootstrap法分析的不确定性明显较小。我们将这种方法应用于玛湖峪流域，得到非平稳条件下的设计洪水。由于在去非平稳过程中考虑了闸坝的确定性影响，bootstrap法分析的不确定性明显较小。我们将这种方法应用于玛湖峪流域，得到非平稳条件下的设计洪水。由于在去非平稳过程中考虑了闸坝的确定性影响，bootstrap法分析的不确定性明显较小。