通过桃江、益阳水文站1980—2015年逐日水位和流量资料,分析资水尾闾水位、流量变化趋势及突变情况,初步探求引起这一变化的原因及其影响。结果表明:近36 a来,资水尾闾径流量年际间呈周期性波动,丰、枯水期交替出现,自2000年以后进入少水期,径流量整体上呈下降趋势,但这一趋势并不显著;受无序采砂导致河床大幅下切及湘水洪道水位降低等因素影响,资水尾闾水位下降,发生均值突变,桃江站降幅达1.72 m,益阳站达0.80 m;因水位突变导致流域水位-流量关系发生明显改变,原有河湖双向互补的关系也发生变化,湖水单一补给入河,一定程度上缓解了资水水位的进一步下降。研究成果可为资水综合开发利用及灾害防治提供科学依据。

According to the daily stage-discharge data during 1980-2015 collected from Taojiang and Yiyang hydrological stations, the trend and abrupt change of water level and flow discharge in the tail of Zishui River are analyzed. On this premise, the causes and influences of aforementioned changes are explored. Results reveal that runoff in the tail of Zishui River fluctuated periodically during the past 36 years with alternating flood and dry periods; ever since the dry period from 2000, runoff has been decreasing overall with an insignificant trend. In the meantime, affected by riverbed downcutting and water level drawdown in Xiangshui flood channel induced by disorderly dredging, water level in the tail of Zishui river declined sharply, and the mean value changed abruptly by 1.72 m at Taojiang station and 0.80 m at Yiyang station. In addition, the abrupt change of water level has brought about evident changes in stage-discharge relation together with the reciprocal relation between river and lake. By replenishing into river unidirectionally, lake water has alleviated the further drawdown of water level in the Zishui river.