湘江2017年与2019年两场特大洪水的对比分析

2017年6月下旬到7月初,2019年7月上旬到中旬,湘江干流接连发生特大洪水。通过分析湘江流域多个测站的水文整编资料,结合部分实时信息,从降雨过程时空分布、干支流有关测站洪水水位流量过程、洪水组成、洪量、洪水传播时间与宣泄速度等方面,对2017年洪水与2019年洪水的暴雨洪水特征进行了对比分析。2017年洪水,湘潭站上游的衡山、衡阳、冷水滩站水位过程与流量过程对应呈双峰形状,而湘潭站水位过程没有出现双峰;2019年洪水,湘江干流上下游站点的水位过程与流量过程基本对应,均呈双峰形状;2017年洪水宣泄慢,2019年洪水宣泄极快。2017年洪水与2019年洪水流量过程与水位过程起伏不对应、洪水宣泄速度的差异主要是由于洞庭湖水位顶托因素影响导致。

Comparative Analysis of Xiangjiang River Catastrophic Floods in 2017 and 2019

Massive floods occurred in Xiangjiang River from late June to early July in 2017 and early July to mid-July in 2019.This paper analyzed the annual hydrological report of Xiangjiang River basin and the real-time hydrological information from the aspects of spatial and temporal distribution of the rainfall process,flood level flow process,flood composition and related flood characteristics.It also compared the storm and flood characteristics of the floods in 2017 and 2019.In 2017,the flood level and flow process of Hengshan,Hengyang,and Lengshuitan stations in the upper reach of Xiangtan station shows a double-peak shape.However,there is no double-peak shape in that of Xiangtan Station;In 2019,the flood level process in the upstream and downstream stations of the mainstream of the Xiangjiang River correspond to the flow process,both of which have a double-peak shape;The flood release rate is low in 2017,but extremely high in 2019.The non-correspondence of the flood flow process in 2017 and 2019 and the difference between their flood discharge rates are mainly resulted from the influence of the Dongting Lake water level jacking.