考虑水位过程变异的非一致性最低通航水位设计方法

在河道断面水位年际变异和年内分配变异的综合作用下,基于历史资料的最低通航水位设计值已无法反映真实的水位变化规律,导致船舶的通航安全面临威胁。为设计出合理的最低通航水位,本文结合分解合成思想和二阶矩变异概念,提出了考虑水位过程变异(即不同时间尺度下水位特征值的年际变异和水位过程的年内分配变异)的非一致性最低通航水位设计方法——频率-保证率法。该方法不仅符合工程水文学中关于设计水文过程的定义,兼顾了年保证率和频率的概念,而且综合考虑了水位年际和年内分配的双重变异,可为其它工程水文设计提供参考。本文将该设计方法应用于澜沧江允景洪水文站,并将设计结果与均值变异条件下采用频率-保证率法、方差变异条件下采用综合历时曲线法的设计结果作比较,对本方法的优势进行了验证和讨论。

Method for designing the lowest navigable water level considering the variation of water level process

The inter- and intra-annual variation of water level series has made the designed lowest navigable water level in the past no longer conforms to the current situation,therefore,navigation safety is facing threats. To solve this problem,this paper proposed a statistical method considering the variation of water level process named "frequency-guaranteed rate method (F-G method)". This method not only conforms to the concept of the hydrological process design in engineering hydrology, but also considers the interand intra-annual variation of water level series comprehensively, providing reference for other engineering hydrological design. The application of this technique is demonstrated in estimating the lowest navigable water level at Yunjinghong hydrological station in the Langcang River basin. The comparison of the designed values among three situations (considering variance variation and using F-G method,only considering mean variation and using F-G method,considering variance variation but using the synthetic duration curve method) was discussed,to prove the advantages of proposed design method.