摘要
筑坝拦截导致河流天然属性的改变,进而影响了相关流域水循环过程。本研究以嘉陵江流域4座梯级水库为对象,于2016年1、4、7、10月份采集水样,分析水体氢氧同位素组成,以期通过氢氧同位素组成的时空变化特征来探讨大坝拦截对于流域水循环的影响。结果表明,表层水体的δ18O和δD沿河流流向上总体有偏正的趋势,应该是受纬度效应及筑坝拦截作用的共同影响;研究区水库库区水体在1、10月的δ18O均值较4、7月偏正,是降雨量与降雨来源不同导致的结果;具有热分层特征的水库(亭子口水库)在夏季分层期的18O值变化范围比其他季节大,其他水库则没有这种特点,另外,水库分层还会使得库区表层水与下泄水的氢氧同位素值出现较大差异;梯级水库的存在使得流域蒸发作用强烈,导致河水氢氧同位素组成大大偏离当地大气降水线,研究区夏季(7月)的蒸发作用最强,春季(4月)次之,冬秋季(1、10月)最弱。
River damming alters natural attributes of rivers, with consequences on water cycle in the river catchment. In this study, water samples including stratified water from four cascadereservoirs in the Jialing River basin were collected in January, April, July, and October in 2016. The hydrogen and oxygen isotopic compositions and their spatial and temporal variations wereanalyzed to assess the impacts of dam interception on water cycle in the river basin. The results showed that the δ18O and δD values of the surface water were generally turning positive along with the flow path due to the latitude effect and the dam interception. The δ18O values of the water samples were more positive in January and October than those in April and July, which should be resulted from the variations in the amount and sources of precipitation. In the summer stratification period, the range of18O value in the reservoir with thermal stratification （Tingzikou reservoir） was larger than that in other seasons. In contrast, it was not the case in other reservoirs. Moreover, reservoir stratification led to divergence in hydrogen and oxygen isotopic compositions between the discharged water and the surface water near dam. The existence of cascade reservoirs enhanced watershed evaporation, which might be responsible for the greater deviation of thehydrogen and oxygen isotope compositions of the river water from the local meteoric water line. The evaporation in the summer （July） was the strongest in the study area, followed by the spring （April） and the weakest in the winter and autumn （January and October）.
出处
《生态学杂志》
CAS
CSCD
北大核心
2018年第3期679-687,共9页
Chinese Journal of Ecology
基金
国家重点研发计划项目(2016YFA0601000)
国家自然科学基金项目(41373136)资助
关键词
梯级水库
氢氧同位素
时空变化
cascade reservoirs hydrogen and oxygen isotopes spatial and temporal variation.
