Flood season segmentation and scheme optimization in the Yellow River

Abstract

River flood season segmentation is a significant measure for flood prevention. This study aims to carry out theoretical analysis on flood season segmentation methods and put forward a framework for proper flood season segmentation through comparison between different segmentation methods. The studied framework consists of a Fisher optimal partition method for determining the optimum numbers of the sub-seasons, an ensemble approach for segmenting a defined flood season, and a nonparametric bootstrap combined with a fuzzy optimum selection method (NB-FOS) for testing the rationality of the flood season staging schemes. The present research findings show that different methods could result in different staging schemes. It is proved through rational analysis that the staging scheme obtained by probability change point (PCP) is superior to others. The flood season of the downstream reach of the Yellow River can be segmented into three sub-seasons, i.e. early flood season (01 June–20 July), main flood season (21 July–28 September), and late flood season (29 September–08 November). The segmentation results of the flood season should play an active role in flood prevention.

The Influence of Time Domain on Flood Season Segmentation by the Fisher Optimal Partition Method

“…Chen, et al (2015) [30] improved the Cunderlik, et al (2004) [31] method of dividing abundance and depletion by month for the whole year, and introduced a fuzzy superiority function to quantitatively evaluate the rationality of flood staging. A more quantitative and accurate evaluation of staging results [18,27,32,33] is widely used compared to the results of multiple staging methods. Li, et al (2021) [34] used the modified Cunderlik method for reasonability analysis based on rainfall data when classifying flood and non-flood periods.…”

“…This will make the application of the method somewhat subjective in time domain selection. At present, when the Fisher optimal partition method is applied to the staging of flood season in China, the time-domain units are generally chosen to be 5-day [27] and 10-day [28]. The reason for choosing 5-day and 10-day units is that as the traditional Chinese timekeeping units, they are better matched with the months and more in line with the seasonal characteristics of agricultural activities.…”

Dynamic Control of Flood Limited Water Levels for Parallel Reservoirs by Considering Forecast Period Uncertainty

“…The staged FLWL accounts for the distinct characteristics of floods, enabling full utilization of flood resources throughout the flood season while maintaining the established flood control standard. Various methods exist to implement flood staging, including the qualitative analysis method [31], set pair analysis [32,33], change-point analysis [34], fuzzy set analysis [35], fractal clustering method [36], and Fisher's optimal segmentation method [37,38], among others. By analyzing flood season staging results, the derived staged FLWL enables efficient utilization of flood resources throughout the season, especially crucial for reservoir operations in the later stages to prevent water scarcity towards the end of the flood season [10].…”

The Method of Segmenting the Early Warning Thresholds Based on Fisher Optimal Segmentation

“…This method can solve the interference of human factors and subjectivity. At present, this method has been widely applied in the fields of agriculture, meteorology, and geological disaster forecasting [22][23][24]. However, it has not been widely applied in the process of determining the early warning thresholds for steep slope deformation.…”