Stormwater drives seasonal geochemical processes beneath an infiltration basin
Stormwater drives seasonal geochemical processes beneath an infiltration basin
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雨水驱动渗透盆地下方的季节性地球化学过程
DOI：
10.1002/jeq2.20416
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发表时间：
2022
影响因子：
2.4
通讯作者：
Sturchio, Neil C.
中科院分区：
文献类型：
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作者：
McQuiggan, Rachel;Andres, A. Scott;Roros, Andreanna;Sturchio, Neil C.
除冰盐是冬季暴风雨期间道路安全的重要组成部分。雨水渗入的最佳管理做法旨在防止盐分污染溪流和水道，但这可能会将污染物转移到地下水资源。针对因雨水渗入最佳管理措施而输入盐分对地下水水质造成影响的有限实地研究，我们使用现场传感器和抓取采样相结合的方法，监测了雨水渗入盆地周围无承压含水层不同深度的水位和地下水水质。我们的观察揭示了地下水化学随含水层深度的不同而不同，以及由雨水(冬季受盐分影响，非冬季新鲜)补给含水层的雨水化学季节性变化所驱动的过程。盆地下方包气带中的水-基质相互作用影响了非冬季补给后钠(Na)向地下水的迁移。相对于氯离子，钠在含水层中的迁移延迟，表明钠在包气带中的滞留时间较长。镉(Ra)浓度与氯浓度相关，表明受盐分影响的补给导致Ra解吸到地下水中，因为盐度增加。由于含水层物质的非均质性，受暴雨影响的地下水遵循优先流动路径，水化学随着流动路径上的时间和位置而变化。这些结果突出了在设计监测网时井网的长度、位置和深度以及观测频率的重要性。
Deicing salt is an important component of road safety during winter storms. Stormwater infiltration best management practices aim to prevent the salt from polluting streams and waterways, but this may shift pollutants to groundwater resources. In response to limited field studies investigating groundwater quality impacts caused by input of salt from stormwater infiltration best management practices, we monitored water levels and quality of groundwater at various depths in an unconfined aquifer around a stormwater infiltration basin using in situ sensors coupled with grab sampling. Our observations revealed differences in groundwater chemistry with depth in the aquifer and processes that were driven by the seasonal changes in the chemistry of stormwater (salt‐impacted in winter and fresh in non‐winter) recharging the aquifer. Water–matrix interactions in the vadose zone beneath the basin affected the transport of sodium (Na) into groundwater following non‐winter recharge. Sodium movement through the aquifer was delayed relative to chloride (Cl), indicating a longer residence time of Na in the vadose zone. Radium (Ra) concentrations were correlated with Cl concentrations, suggesting salt‐impacted recharge caused desorption of Ra into groundwater because of increased salinity. Stormwater‐influenced groundwater followed a preferential flow path due to heterogeneity of the aquifer materials, and water chemistry varied with time and location along the flow path. These results highlight the importance of well screen length, placement and depth, and frequency of observations when designing a monitoring network.