淮河流域水库(群)对河流氢氧同位素组成的影响

The Effects of Reservoirs on Hydrogen and Oxygen Isotope Compositions of Reservoirs and Rivers in the Huaihe River Basin

水利工程建设对河流地貌、水生态环境系统及水文特征的影响引起了人们的广泛关注。以淮河流域支流史灌河上2座水库,梅山水库和鲇鱼山水库为研究区域,在2020年12月分别对水库水体、水库下游蒋家集断面、淮河干流上下游断面王家坝和润河集断面进行采样,分析其水化学离子、电导率和氢氧同位素含量及时空变化特征,探讨水库修建对于流域水循环的影响。研究结果表明,受到筑坝拦截和纬度效应的影响,水体两种同位素组成沿河流流向上变化趋势一致,总体偏正。梅山水库和鲇鱼山水库水体的同位素时程变化比较平稳,上游王家坝站时程变化比较平稳,支流和干流上受水库影响的2个断面同位素时程变化波动较大。蒸发作用由于水库的拦截影响较一般河流更强,导致水库和河水氢氧同位素组成偏离当地大气降水线。受水库下泄水影响,下游蒋家集和润河集Cl-和电导率的值有所下降,其中,离水库较近的蒋家集受到的影响更大。

An increasing and wide attention has been paid to the effect of artificial reservoirs on river geomorphology,water ecological environment system and hydrological characteristics. In this paper,two reservoirs on the Shiguan River,a tributary of the Huaihe River Basin,Meishan Reservoir and Nianyushan Reservoir are used as the study area. Samples are taken from the water body of the reservoirs,the Jiangjiaji section in the downstream of the reservoir,the Wangjiaba and Runheji sections at the upstream and downstream sections of the main stream of the Huaihe River in December 2020 to analyze the spatiotemporal variation characteristics of hydrochemistry ion,electrical conductivity,hydrogen and oxygen isotope content,and discuss the impact of reservoir construction on the water cycle of the basin. The results show that the two isotopic compositions of the water body have the same trend along the river direction,and the overall trend is positive. One is the dam interception and the other is the influence of latitude effect. The temporal change of isotopic concentration of the water bodies in the Meishan Reservoir and Nianyushan Reservoir is relatively stable,the isotopic temporal change of the upstream Wangjiaba Station is relatively stable,and that of the two sections on the tributary and the main stream affected by the reservoir fluctuates greatly. Hydrogen and oxygen isotopic composition of the river and the reservoir deviates from the local atmospheric precipitation line,mainly due to the interception effect of the reservoir,so that the evaporation is stronger than that of the ordinary river. The lower reaches of Jiangjiaji and Runheji Cl-and the electrical conductivity are affected by the water discharge from the reservoir,the value of which decreases. Jiangjiaji is closer to the reservoir and has a greater impact.