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- Adyasari, D., et al.
(författare)
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Radon-222 as a groundwater discharge tracer to surface waters
- 2023
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Ingår i: Earth-Science Reviews. - : Elsevier BV. - 0012-8252. ; 238
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Tidskriftsartikel (refereegranskat)abstract
- The naturally occurring isotope radon-222 (222Rn) is widely employed as a tracer for groundwater discharge to lakes, lagoons, rivers, estuaries, and coastal oceans. However, owing to the highly diverse hydrogeological settings, limitations, and assumptions when applying the 222Rn mass balance, there is a clear need to create a uniform approach that will constrain the uncertainties in the reported groundwater fluxes. This review paper provides an overview of the 222Rn measurement techniques and discusses 222Rn mass balances and their application to various hydrological environments. We address the primary uncertainties faced when applying 222Rn mass balances including, (1) atmospheric evasion, (2) groundwater endmember, (3) offshore mixing loss, (4) steady-state assumptions, and (5) upscaling groundwater discharge from 222Rn measurements, and methods that can be applied to minimize these uncertainties. Finally, we provide guidelines and open-source scripts (i.e., R codes and FINIFLUX) that should assist future studies using 222Rn to quantify groundwater discharge to surface waters.
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| 2. |
- McKenzie, Tristan, et al.
(författare)
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Traditional and novel time-series approaches reveal submarine groundwater discharge dynamics under baseline and extreme event conditions
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Groundwater is a vital resource for humans and groundwater dependent ecosystems. Coastal aquifers and submarine groundwater discharge (SGD), both influenced by terrestrial and marine forces, are increasingly affected by climate variations and sea-level rise. Despite this, coastal groundwater resources and discharge are frequently poorly constrained, limiting our understanding of aquifer responses to external forces. We apply traditional and novel time-series approaches using an SGD dataset of previously unpublished resolution and duration, to analyze the dependencies between precipitation, groundwater level, and SGD at a model site (Kiholo Bay, HawaiModified Letter Turned Commai). Our objectives include (1) determining the relative contribution of SGD drivers over tidal and seasonal periods, (2) establishing temporal relationships and thresholds of processes influencing SGD, and (3) evaluating the impacts of anomalous events, such as tropical storms, on SGD. This analysis reveals, for example, that precipitation is only a dominant influence during wet periods, and otherwise tides and waves dictate the dynamics of SGD. It also provides time lags between intense storm events and higher SGD rates, as well as thresholds for precipitation, wave height and tides affecting SGD. Overall, we demonstrate an approach for modeling a hydrological system while elucidating coastal aquifer and SGD response in unprecedented detail.
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