摘要
山区侧向补给是华北山前平原冲洪积扇含水层重要补给来源,影响平原区地下水水量和水质动态。近年来受极端气候和人类活动影响,山区对冲洪积扇平原区地下水的侧向补给机制及其对地下水硝酸盐动态的影响仍不明确。本研究以滹沱河冲洪积扇为研究区,利用水文观测、水化学和同位素示踪等方法,估算山区侧向补给通量和硝酸盐输移通量,揭示山区侧向补给与平原区地下水的补给关系,分析山区侧向补给对地下水硝酸盐分布的影响。根据水文地质条件,将采样点划分为4个子区:滹沱河冲洪积扇北部扇顶(Ⅰ区)、扇中(Ⅱ区)、滹沱河附近扇缘区(Ⅲ区)以及滹沱河冲洪积扇南部区域(Ⅳ区)。地下水硝酸盐动态监测数据表明,滹沱河北部的山区断面地下水硝酸盐浓度高于南部断面,平原区北部Ⅰ区和Ⅱ区地下水硝酸盐浓度高于南部Ⅳ区;且沿地下水流动方向,地下水硝酸盐浓度均值呈现Ⅰ区(105.28 mg·L^(−1))>Ⅱ区(99.22 mg·L^(−1))>Ⅳ区(37.10 mg·L^(−1))>Ⅲ区(23.08 mg·L^(−1))的空间分布特征。利用地下水氢氧同位素示踪揭示了山区侧向流对冲洪积扇北部地下水补给影响范围为扇顶和扇中,而冲洪积扇南部因地下水超采改变地下水流场,其影响范围主要为扇顶。利用达西定律计算2022年3月至2023年2月山区侧向流对滹沱河冲洪积扇平原区的补给量为2.10×10^(8)m^(3),硝酸盐通量为239.56×10^(5)kg,且北部山区侧向补给的水氮通量大于南部,这也是影响平原区地下水硝酸盐空间分布的重要原因。山区侧向补给对冲洪积扇平原区地下水量和水质的影响不容忽视,因此,实现源头综合治理,降低山区地下水污染物浓度,对下游平原区面源污染管理,防止地下水硝酸盐污染具有重要意义。
Lateral recharge in mountainous areas is an important recharge source for the alluvial-pluvial fans in the Piedmont Plain of North China,which affects the dynamics of the quantity and quality of groundwater in plain areas.In recent years,the mechanism of lateral recharge in mountainous areas of groundwater in alluvial-pluvial fans and its influence on the dynamics of nitrate in groundwater in plain areas have remained unknown due to extreme climate and human activities.Through hydrological observation and hydrochemical and isotope tracer methods across the Hutuo River alluvial-pluvial fan,we estimated the lateral recharge flux and nitrate transport flux in mountainous areas,revealed the recharge relationship between lateral recharge in mountainous areas and groundwater in plain areas,and analyzed the influence of lateral recharge in mountainous areas on the distribution of groundwater nitrate in plain areas.The sampling sites were divided into four sub-regions according to their hydrogeological conditions:the northern top part(ZoneⅠ)and the middle(ZoneⅡ)of the Hutuo River alluvial-pluvial fan,the fan margin area near the Hutuo River(ZoneⅢ),and the southern part of the Hutuo River alluvial-pluvial fan(ZoneⅣ).The monitoring data of groundwater nitrate dynamics showed that the nitrate concentration of groundwater in the mountainous section of the northern Hutuo River was higher than that in the southern section,and the nitrate concentration of groundwater in ZonesⅠandⅡof the northern alluvial-pluvial fan plain was higher than that in ZoneⅣ.Along the direction of groundwater flow,the mean concentration of groundwater nitrate showed a spatial distribution pattern of ZoneⅠ(105.28 mg·L^(−1))>ZoneⅡ(99.22 mg·L^(−1))>ZoneⅣ(37.10 mg·L^(−1))>ZoneⅢ(23.08 mg·L^(−1)).The results revealed that the influenced areas by lateral recharge in mountainous areas in the northern part of the alluvial fan were the top and middle of the fan.However,the influenced area in the southern part of the alluvial fa
作者
孙和平
王仕琴
郑文波
檀康达
曹文庚
沈彦俊
SUN Heping;WANG Shiqin;ZHENG Wenbo;TAN Kangda;CAO Wengeng;SHEN Yanjun(Center for Agricultural Resources Research,Institute of Genetics and Developmental Biology,Chinese Academy of Sciences/Key Laboratory of Agricultural Water Resources,Chinese Academy of Sciences/Hebei Key Laboratory of Water-Saving Agriculture,Shijiazhuang 050022,China;University of Chinese Academy of Sciences,Beijing 100049,China;Institute of Hydrogeology and Environmental Geology,Chinese Academy of Geological Sciences,Shijiazhuang 050061,China)
出处
《中国生态农业学报（中英文）》
CAS
CSCD
北大核心
2023年第11期1839-1850,共12页
Chinese Journal of Eco-Agriculture
基金
国家重点研发计划青年科学家项目(2021YFD1700500)
河北省自然科学基金创新研究群体项目(D2021503001)资助。
关键词
山区侧向补给
地下水补给
硝酸盐
滹沱河冲洪积扇
Lateral recharge in mountainous areas
Groundwater recharge
Nitrate
Hutuo River alluvial-pluvial fan
