Comparison of groundwater age models for assessing nitrate loading, transport pathways, and management options in a complex aquifer system
Comparison of groundwater age models for assessing nitrate loading, transport pathways, and management options in a complex aquifer system
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用于评估复杂含水层系统中硝酸盐负荷、迁移路径和管理选项的地下水年龄模型的比较
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发表时间：
2018
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通讯作者：
Seung Hyun Lee
中科院分区：
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作者：
E. Koh;Eunhee Lee;D. Kaown;C. T. Green;D. Koh;K. Lee;Seung Hyun Lee
在水文地质复杂的含水层系统中，不同年龄的地下水在不同的流动路径下可能发生混合。在这项研究中，我们应用不同的地下水年龄估算技术（集中参数模型和数值模型）来表征济州岛高山农田地下水年龄分布和硝酸盐污染的主要途径。根据集总参数模型，研究区地下水年龄可以用年轻地下水（4-33年）和老水成分（> - 60年）的二元混合来解释。研究区观测到的复杂水文地质条件和局部非均质性（多层含水层、井漏水力）在数值模型中得到了很好的反映。数值模型预测，与其他模型相比，高山地区含水层对化肥施用的响应更快（平均年龄为9.7 ~ 22.3年）。我们的研究结果表明，多种年龄估算方法的应用和比较有助于更好地了解不同年龄（路径）地下水的流动状态和混合特征，从而降低因含水层非均质性而导致的不当地下水管理计划的风险。
In an aquifer system with complex hydrogeology, mixing of groundwater with different ages could occur associated with various flow pathways. In this study, we applied different groundwater age‐estimation techniques (lumped parameter model and numerical model) to characterize groundwater age distributions and the major pathways of nitrate contamination in the Gosan agricultural field, Jeju Island. According to the lumped parameter model, groundwater age in the study area could be explained by the binary mixing of the young groundwater (4–33 years) and the old water component (>60 years). The complex hydrogeologic regimes and local heterogeneity observed in the study area (multilayered aquifer, well leakage hydraulics) were particularly well reflected in the numerical model. The numerical model predicted that the regional aquifer of Gosan responded to the fertilizer applications more rapidly (mean age: 9.7–22.3 years) than as estimated by other models. Our study results demonstrated that application and comparison of multiple age‐estimation methods can be useful to understand better the flow regimes and the mixing characteristics of groundwater with different ages (pathways), and accordingly, to reduce the risk of improper groundwater management plans arising from the aquifer heterogeneity.