Category Archives: Application example

miniRUEDI at DIVE

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Isterre Laboratory (Grenoble, France) and GFZ (Potsdam, Germany) joined their efforts to monitor gases while drilling in real-time within the frame of the DIVE ICDP project. Two boreholes of nearly one kilometer deep have been drilled in the Ivrea-Verbano Zone (Italy) to probe the deep continental crust and its transition to the mantle. The miniRUEDI, together with other gas analyzers, was deployed successfully all along the course of the drilling operations (working non stop two times four months in a row). Hugo Dutoit (PhD candidate at University Grenoble Alpes) was in charge of the monitoring. The obtained data reveal that that migration of deep fracture fluids can be tracked via mud gas logging.

Laurent Truche, Hugo Dutoit, Thomas Wiersberg, and their colleagues

How gases travel in lakes

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An international team of researchers used several miniRUEDIs to study the 3D transport of dissolved gases in a eutrophic lake. The water in the littoral zone cools faster during the night and therefore causes a lateral «syphon stream» that transports water along the sediment, and which is balanced by corresponding water flow at the surface. Krypton was injected into the littoral water to track the syphon stream, and to quantify the transport of other, naturally abundant gases in the lake. High-frequency miniRUEDI measurements demonstrate that daily convective horizontal circulation generates littoral-pelagic transport one order of magnitude larger than typical horizontal fluxes assumed in previous gas budgets. These lateral fluxes are sufficient to redistribute gases at the basin-scale and generate concentration anomalies reported in other lakes.

Tomy Doda, et al., “Lake surface cooling drives littoral-pelagic exchange of dissolved gases”, Science Advances, 2024. DOI: 10.1126/sciadv.adi0617

miniRUEDI sniffs groundwater flow

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The Swiss Federal Institute of Aquatic Science and Technology (Eawag) and their partners at CHYN and Rhesi used a miniRUEDI to track the groundwater flow near a large channelized river. The river bed was excavated to simulate a natural erosion event, as it might occur after river revitalisation. Different groundwater flow paths were artificially spiked with different noble gases, and their break-through curves at a nearby pumping well were monitored with a miniRUEDI. The spiking was repeated several times over a period of one year. These measurements show how the river/groundwater exchange evolves in response to the excavation and to the «healing» of the eroded river bed. This new tracer tool and the resulting insights will be important for groundwater management and drinking water production near revitalised river systems.

An unusual marriage of miniRUEDI data, environmental DNA and vanadium tracers shows that Mt. Fuji isn’t as easy as previously thought

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Mount Fuji’s freshwater springs are not only fed by water recharged at high altitude, but also by the upwelling of deep groundwater. This was observed by Oliver Schilling and his team, who used miniRUEDI data combined with environmental DNA and vanadium tracers. Read the full story in Nature Water.

miniRUEDI as a new tool for multi-gas tracer tests (not only) in groundwaters

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Eawag and Uni Neuchatel teamed up to develop and test the miniRUEDI as a tool for artificial tracer tests using different noble gases.

In a first test, helium pulses were injected into a river. A miniRUEDI was used to analyse the He concentrations in the nearby groundwater system, where the observed He breakthrough indicated a substantial loss of river water to the underlying aquifer.

In a second test, multiple pulses of different noble gases (He, Kr and Xe) were repeatedly injected at different locations into an aquifer. A miniRUEDI was used to record the breakthrough curves of the different gases in the downstream groundwater flow, which provided insights into the groundwater flow field, and showed how the flow field responded to modifications in the hydraulic connectivity of a nearby river to the aquifer.

In both tests, the miniRUEDIs efficiently provided valuable new insights into river/groundwater exchange and its effects on the groundwater quality.

Publications:

  1. T. Blanc, M. Peel, M.S. Brennwald, R. Kipfer, P. Brunner: Use of helium as an artificial tracer to study surface water/groundwater exchange. EGU21-9005, doi: 10.5194/egusphere-egu21-9005

  2. M.S. Brennwald, M. Peel, T. Blanc, Y. Tomonaga, R. Kipfer, P. Brunner, D. Hunkeler: New Experimental Tools to Use Noble Gases as Artificial Tracers for Groundwater Flow. Frontiers Water, doi: 10.3389/frwa.2022.925294

miniRUEDI shows how gases control the accumulation of arsenic in drinking water resources

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Alex Lightfoot and her colleagues at Eawag, CSIRO, RIBES, and KIT used a miniRUEDI to study the interaction of groundwater with gases trapped in an aquifer in the Red River delta (Vietnam). They demonstrated how the gas controls the mobilisation and accumulation of arsenic in the groundwater, which is an important drinking water source.

Full paper: Alexandra K. Lightfoot, Matthias S. Brennwald, Henning Prommer, Emiliano Stopelli, Michael Berg, Martyna Glodowska, Magnus Schneider, Rolf Kipfer. Noble gas constraints on the fate of arsenic in groundwater. Water Research, doi: 10.1016/j.watres.2022.118199

Understanding PCE contamination of groundwaters

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In their recent recent paper, Chrisitan Moeck and his Eawag colleagues used a miniRUEDI to study the groundwater flow and perchloroethylene (PCE) transport in an urban aquifer system. They used dissolved He concentrations measured with a miniRUEDI to establish a relationship with 3H/3He groundwater ages, which allowed them to characterize the water flow and provided conceptual understanding of the groundwater system. The combination of the groundwater age data (miniRUEDI He, 3H/3He) with hydrochemical data, water isotopes (18O and 2H), and PCE concentrations showed the spatial inter-aquifer mixing between artificially infiltrated groundwater and water originating from regional flow paths. Furthermore, the correlation of groundwater age with PCE concentration explained the spatial distribution of PCE contaminations within groundwater system. In addition, faults were observed to provide preferential flow paths that lead to elevated PCE concentrations.

Full paper: C. Moeck, A.L. Popp, M.S. Brennwald, R. Kipfer, M. Schirmer: Combined method of 3H/3He apparent age and on-site helium analysis to identify groundwater flow processes and transport of perchloroethylene (PCE) in an urban area. J. Contaminant Hydrology, doi: 10.1016/j.jconhyd.2021.103773

From Snow to Groundwater

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Oliver Schilling (Université Laval and Centre for Hydrogeology and Geothermics) and his colleagues used a miniRUEDI for on-site quantification of dissolved He, Ar, Kr, N2, O2 and CO2 in groundwaters of a boreal catchment in Canada. The gas data allowed them to quantify the contribution of snowmelt to groundwater recharge, to analyze the temporal recharge dynamics, and to identify the primary recharge pathways. Furthermore, they observed a systematic depletion of N2 in groundwater, which provides insights into the biological N‐fixation in boreal forest soils.

Full paper: O. S. Schilling, A. Parajuli, C. Tremblay Otis, T. U. Müller, W. Antolinez Quijano, Y. Tremblay, M. S. Brennwald, D. F. Nadeau, S. Jutras, R. Kipfer, R. Therrien. Quantifying groundwater recharge dynamics and unsaturated zone processes in snow‐dominated catchments via on‐site dissolved gas analysis. Water Research, doi: 10.1029/2020WR028479

Lake Kivu will not explode anytime soon, says miniRUEDI

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Fabian Bärenbold and his coworkers studied the gases in Lake Kivu in East Africa, which is well known for its huge reservoir of CH4 and CO2 dissolved in the deep waters. In view of the ongoing and planned extraction of CH4 for energy production, Fabian Bärenbold and his colleagues used a miniRUEDI and other gas analysis techniques (gas chromatography, laser spectrometery, and a total dissolved gas pressure). The measurement results show good agreement within 5–10%. The CH4 and CO2 dioxide concentrations in Lake Kivu are very similar to earlier results observed during the past few decades, which indicates that the risk for a limnic gas erruption of Lake Kivu has not increased.

Full paper: Fabian Bärenbold, Bertram Boehrer, Roberto Grilli, Ange Mugisha, Wolf von Tümpling, Augusta Umutoni, Martin Schmid. No increasing risk of a limnic eruption at Lake Kivu: Intercomparison study reveals gas concentrations close to steady state. PLOS, doi: 10.1371/journal.pone.0237836