长江流域洪水汛情分布与水位-流量特征关系分析

Analysis of the relationship between flood distribution and water level-discharge characteristics in the Yangtze River

为更好为长江流域防洪防汛提供决策依据,本研究收集了2020年6~8月期间长江流域内共28个河流水文站的水位-流量观测数据,结合水文站空间位置,分析长江汛期的洪水汛情空间分布与水位-流量特征关系。研究表明,长江上游在8月期间发生严重的洪水汛情,上游寸滩站超出警戒水位最高可达11 m;整体来看,汉江与长江交汇处及其以下区域是汛情最为严重的区域,长江中下游洪水历时长、流量大、最高水位持续时间长、干支流洪水并发。对2015—2017年部分水文站历史数据进行对比分析发现,汉江与长江交汇处仙桃水文站的汛情与水位-流量之间存在典型关系,汛情与水位-流量特征系数为正相关关系,可以根据该水文站2016年和2020年的特征系数尽早采取不同等级的防汛措施。

In order to provide a decision-making basis for flood control in the Yangtze River,this study collected the water level-discharge observation data of a total of 28 river hydrological stations in the Yangtze River from June to August in 2020.Combined with the spatial location of the hydrological station,the relationship between the spatial distribution of floods and the characteristics of water level-discharge during the flood season of the Yangtze River was analyzed.This study has shown that severe flooding occurred in the upper reaches of the Yangtze River during August,and that the upper reaches of the Cuntan station exceeded the warning level by up to 11 m.The confluence of the Han River and the Yangtze River and the area below it were the most severe areas of flooding.The floods in the middle and lower reaches of the Yangtze River lasted for a long time,the flow was large,the highest water level was high,and the main and tributary floods occurred concurrently.A comparative analysis of the historical data from some hydrological stations from 2015 to 2017 found that there was a typical relationship between the flood situation and the water level-discharge of the Xiantao Hydrological Station at the intersection of the Han River and the Yangtze River.There was a positive correlation between flood situation and water level-discharge characteristic coefficient.The characteristic coefficients of the hydrological station in 2016 and 2020 will be implemented as early as possible for different levels of flood control measures.