格尔木河222Rn同位素变化及其对地表水-地下水交互关系的指示意义
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格尔木河222Rn同位素变化及其对地表水-地下水交互关系的指示意义
摘 要:2019年5月和8月两次在格尔木河流域采集河水、地下水样品,测量222Rn浓度和典型断面流量,结果发现:(1)山区河段河水222Rn浓度最高,平均值为948.72 Bq·m-3,指示基岩裂隙水是山区河段重要补给来源;(2)山前冲洪积扇河水222Rn浓度最低,平均值为76.71 Bq·m-3,地下水补给较少;(3)溢出带地区河水222Rn浓度上升至平均676 Bq·m-3,地下水溢出补给河水,向下至细土平原,河水222Rn浓度呈下降趋势。(4)时间变化上,8月与5月相比,河水222Rn浓度下降,表明地下水补给减少。(5)溢出带S1~S2河段河水与地下水交互关系以双向转化为主,基于质量守恒原理计算河水与地下水交互通量,5月和8月累积河水渗漏通量分别为3.87 m3·s-1和0.9 m3·s-1,地下水补给通量分别为0.51 m3·s-1和0.47 m3·s-1,河水渗漏强度大于地下水补给,二者交互通量存在时空差异。
1.中国科学院西北生态环境资源研究院 沙漠与沙漠化重点实验室,甘肃 兰州 730000
2.中国科学院大学,北京 100049
Variability of 222Rn in Golmud River and its implication for surface-groundwater interaction
Abstract: Research of water cycle and runoff variation has always been a difficult issue of assessment of water resources in arid basins. In May and August, 2019, samples of river water and groundwater had taken, then 222Rn concentration of these samples were measured and river runoff were also gauged. Then spatial and temporal characteristics of 222Rn concentrations in river water and groundwater had analyzed, together with interactions between them. The results show that (1) 222Rn concentration of river water in mountains are high, with a mean value of 948.72 Bq·m-3, indicating that groundwater coming out of bedrock fissure water is an important source of river water in the mountains, especially near a tectonic faults; (2) 222Rn concentration of river water in the alluvial floodplain with less groundwater recharge are low, 76.71 Bq·m-3 in average; (3) 222Rn concentration rises to average 676 Bq·m-3 in the transitional zone of alluvial floodplain and low-lying plain, where groundwater recharges to the river as spring. Toward downstream low plain, 222Rn concentration of river water go down again; (4) temporally, compared to May, 222Rn concentration of river water is relatively low in August, showing a decline of groundwater recharge; (5) 222Rn concentration of groundwater is 2-3 orders of magnitude higher than river water and demonstrate a spatial variation of high in the middle whereas low in the east and west; (6) in S1~S2, two concurrent processes of groundwater discharging to river and river water leaking to groundwater dominate the surface-groundwater interaction. A mass balance method was used to calculate the exchange flux which indicates accumulated river leakage flux in May and August is 3.87 m3·s-1 and 0.9 m3·s-1, separately, while 0.51 m3·s-1 and 0.47 m3·s-1 for groundwater discharge flux. River leakage is more powerful than river discharge and the flow flux between surface and groundwater varies noticeably in different sections and different time.
1. Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
摘要:
摘 要:2019年5月和8月两次在格尔木河流域采集河水、地下水样品,测量222Rn浓度和典型断面流量,结果发现:(1)山区河段河水222Rn浓度最高,平均值为948.72 Bq·m-3,指示基岩裂隙水是山区河段重要补给来源;(2)山前冲洪积扇河水222Rn浓度最低,平均值为76.71 Bq·m-3,地下水补给较少;(3)溢出带地区河水222Rn浓度上升至平均676 Bq·m-3,地下水溢出补给河水,向下至细土平原,河水222Rn浓度呈下降趋势。(4)时间变化上,8月与5月相比,河水222Rn浓度下降,表明地下水补给减少。(5)溢出带S1~S2河段河水与地下水交互关系以双向转化为主,基于质量守恒原理计算河水与地下水交互通量,5月和8月累积河水渗漏通量分别为3.87 m3·s-1和0.9 m3·s-1,地下水补给通量分别为0.51 m3·s-1和0.47 m3·s-1,河水渗漏强度大于地下水补给,二者交互通量存在时空差异。
中图分类号:
P641.3