| 引用本文: | 孙玉芳,海 晶,金晓媚,等.青铜峡灌区排水沟—地下水水化学特征及转换关系分析[J].灌溉排水学报,2023,42(9):110-118. |
| SUN Yufang,HAI Jing,JIN Xiaomei,et al.青铜峡灌区排水沟—地下水水化学特征及转换关系分析[J].灌溉排水学报,2023,42(9):110-118. |
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| 摘要: |
| 【目的】分析青铜峡灌区浅层地下水与排水沟的水化学和同位素特征，揭示地表水与地下水之间的转换。【方法】综合运用数理统计、Gibbs模型、Piper图、Schoeller图、阳离子交替吸附作用图等方法，系统分析排水沟水及周围浅层地下水的水化学特征，探讨排水沟与周围浅层地下水的转化关系。【结果】排水沟水总体呈弱碱性或碱性，TDS在休灌期大于灌期；浅层地下水TDS在休灌期和灌期差别不大，但都明显大于排水沟。排水沟和浅层地下水阳离子：Na+>Ca2+>Mg2+>K+，阴离子：Cl->SO42->HCO3-。排水沟附近的浅层地下水离子浓度垂向上的差异大于水平方向上的差异。排水沟和浅层地下水的δ18O和δD在灌期和休灌期差异都不明显，30 m深度浅层地下水同位素贫化明显。【结论】排水沟与浅层地下水的水化学组分受蒸发浓缩和岩石风化作用的控制，同时受混合作用和离子交换作用影响，浅层地下水比排水沟受离子交换作用更加显著。灌区南部浅层地下水更靠近岩石风化控制区，中部和北部样点更靠近蒸发浓缩控制区。灌区内排水沟排泄地下水和补给地下水两种模式同时存在，排水沟主要排泄灌溉退水，灌溉退水比例平均值达到81.54%，而部分排水沟不仅没有能够排水，还成为附近浅层地下水的重要补给来源，补给比例最高达到84.62%。 |
| 关键词: 青铜峡灌区；排水沟；水化学；同位素；转化关系 |
| DOI：10.13522/j.cnki.ggps.2023058 |
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| 基金项目: |
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| Hydrochemical Relationship between Water in Drainage Ditches and Shallow Groundwater in Qingtongxia Irrigation Area |
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SUN Yufang, HAI Jing, JIN Xiaomei, ZHAO Zhipeng, LI Hongbo, ZHU Wei
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1.School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China;
2.Hydrology & Environmental Geological Survey Institute of Ningxia Hui Autonomous Region, Yinchuan 750026, China;
3.Bureau of Geology of Ningxia Hui Autonomous Region, Yinchuan 750021, China
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| Abstract: |
| 【Objective】Change in groundwater in Qingtongxia Irrigation areas is mainly due to the leaching of drainage ditches and infiltration of field irrigation. The exchange between surface water and groundwater is frequent but complex. This paper analyzes the hydrochemical relationship between water in drainage ditches and their adjacent shallow groundwater.【Method】The study was based on hydrochemical data measured from water samples taken from both drainage ditches and shallow groundwater. Their correlations and transformation were analyzed using statistics, Gibbs model, Piper chart, Schoeller chart, cation alternating adsorption chart and other methods.【Result】The water in the drainage ditches was more alkaline in the off-irrigation period, and slightly alkaline or alkaline in the irrigation period. In contrast, the shallow groundwater was neutral or weakly alkaline in the off-irrigation period and weakly alkaline or alkaline in the irrigation period. The TDS of the water in the drainage ditches was higher in irrigation period than in off-irrigation period, while the TDS of the shallow groundwater remained approximately same, though it was significantly higher than that of the drainage ditches. The content of cations in the water in both the drainage ditches and shallow groundwater were ranked in the order of Na+>Ca2+>Mg2+>K+, while the anions were in the order of Cl->SO42->HCO3-. The difference in ion concentration in the shallow groundwater near the drainage ditches was greater in the vertical direction than in the horizontal direction. The δ18O and δD in the ditch water and shallow groundwater were approximately the same during both irrigation and off-irrigation periods, and their spatial variation was small. The isotope dilution by shallow groundwater was noticeable at the depth of 30 m.【Conclusion】The chemical compositions of ditch water and shallow groundwater are controlled by evaporation or rock weathering, in addition to hydrodynamic mixing. The hydrochemistry in the shallow groundwater in the south of the area depends on rock weathering, while that in the middle and north of the area is largely modulated by evaporation. Depending on the depth of groundwater table, the drainage ditch can ether discharge or drain the groundwater due to the rise of groundwater table following irrigation. The average ratio of irrigation water withdrawal was 81.54%. For regions where groundwater table is deep, the drainage ditch is the main source of groundwater, accounting for 84.62% of water supply to the groundwater. |
| Key words: Qingtongxia irrigation area; drainage ditch; hydrochemical characteristics; Isotope; transformation relation |
