摘要
以2022年洞庭湖为研究背景,以资江洞庭湖河段为研究对象,采用水化学和氡同位素联合示踪的方法,探讨洞庭湖区不同季节河水地下水相互作用关系,以揭示极端气候条件下湖区河道水交换的异常变化。1月和8月研究河段河水均为HCO_(3)-Ca型,地下水分别为HCO_(3)-Ca型和HCO_(3)-Ca与HCO_(3)·SO_(4)-Ca型,均主要受岩石溶滤控制,且均表现出河水地下水一定程度混合的特征。1月和8月地下水^(222)Rn浓度平均分别是河水的21和23倍,且两类水体均为1月高于8月。1月和8月河水TDS和Cl^(-)沿程均小幅度起伏变化,地下水中则以与河水总体相近的趋势大幅度波动;1月河水和地下水^(222)Rn浓度沿程为总体先升后降的大幅度波动特征,8月则表现为上半河段变化趋势相反、下半河段趋势相近。综合分析认为:1月和8月研究河段上游和下游一定范围内均为地下水补给河水,中部一定范围内补给减弱;1月和8月地下水补给河水的速率分别为0.39×10^(-4)和0.44×10^(-4) m^(3)/(s·m),补给量分别为1.24和1.39 m^(3)/s。2022年的极端气候导致洞庭湖平原区河水和地下水相互作用关系出现异常,研究河段1月地下水补给河水强度增加,8月由通常的河水补给地下水逆转为地下水补给河水。极端气候不仅影响了洞庭湖平原河道水交换模式和强度,还可能导致河道生态系统的物质循环和能量流动功能出现异常。
Setting 2022 as the time background,and the Zijiang River segment in Dongting Lake as the study area,hydrochemistry and Rn isotope tracing were adopted to study the river-groundwater interaction in the Dongting Lake,and to reveal the abnormal change of the water exchange along rivers under the extreme climate condition.In January and August,the hydrochemistry type of the river water was HCO_(3)-Ca,and that of the groundwater was HCO_(3)-Ca and HCO_(3)-Ca to HCO_(3)·SO_(4)-Ca,respectively.The rock leaching are the main controlling factor of the river water and groundwater,and river water and groundwater may have experienced mixing.The 222 Rn concentration in the groundwater in January and August was 21 and 23 times that of the river water,respectively,and ^(222)Rn in the river and groundwater in January were higher than that in August.In January and August,TDS and Cl^(-)in the river fluctuated slightly along the river,while those in the groundwater increased and decreased in great degree with similar overall trend to the river water.^(222)Rn in the river and groundwater fluctuated greatly and increased first and then decreased along the river in January,while that in the two types of water bodies changed with opposite tendency along the upper part of the river,and with similar characteristics along the lower part of the river in August.The hydrochemistry and Rn isotope characteristics indicated that the groundwater discharge into the river along the upper and lower part of the study river segment,and the discharge weakened along the middle part in January and August.The discharge rate and flux along the study river segment in January and August was 0.39×10^(-4) and 0.44×10^(-4) m^(3)/(s·m)and 1.24 and 1.39 m^(3)/s,respectively.The extreme climate resulted in the abnormal change of river-groundwater interaction in Dongting basin.Along the study river segment,the groundwater discharge intensity increased in January,and the recharge model changed from river-into-groundwater to groundwater-into-river in August.The extreme climate not only influenced the model and intensity of the water exchange along rivers in the Dongting Basin,but probably caused the abnormal change of matter cycle and energy flow in the river ecosystem.
作者
谌宏伟
朱智超
李正最
喻娓厚
周慧
于莎莎
彭向训
CHEN Hongwei;ZHU Zhichao;LI Zhengzui;YU Weihou;ZHOU Hui;YU Shasha;PENG Xiangxun(School of Hydraulic and Environmental Engineering,Changsha University of Science&Technology,Changsha 410114,China;Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province,Changsha University of Science&Technology,Changsha 410114,China;Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province,Changsha University of Science&Technology,Changsha 410114,China;Hunan Hydrology and Water Resources Survey Center,Changsha 410005,China)
出处
《地学前缘》
北大核心
2025年第2期445-455,共11页
Earth Science Frontiers
基金
湖南省水利科技重大项目(XSKJ2019081-09)。
关键词
水化学
氡同位素
河水
地下水
相互作用
极端气候
洞庭湖
hydrochemistry
Rn isotope
river water
groundwater
interaction
extreme climate
Dongting Lake
