HS8.2.1 | Innovative methods and new advances for understanding subsurface processes that couple fluid dynamics, solute transport, geochemical reactions and biological activity
EDI
Innovative methods and new advances for understanding subsurface processes that couple fluid dynamics, solute transport, geochemical reactions and biological activity
Co-organized by SSS6
Convener: Maria Klepikova | Co-conveners: Yves Meheust, Nataline Simon, Oshri Borgman, Pietro De Anna, Clement Roques, Vittorio Di Federico
Orals
| Mon, 24 Apr, 08:30–12:25 (CEST)
 
Room 2.15
Posters on site
| Attendance Mon, 24 Apr, 16:15–18:00 (CEST)
 
Hall A
Orals |
Mon, 08:30
Mon, 16:15
A number of physical (e.g. flow and transport), chemical (e.g. red-ox reactions) and biological (e.g. bio-mineralization) mechanisms are critical to the fate of geologic media where rocks, liquids, gases and microbes are in close interactions. The characterization and modeling of the complex interplay between these mechanisms is fundamental to our understanding of subsurface processes occurring in contaminant transport and remediation in groundwater and the vadose zone, in the geological storage of energy, CO2 and H2, as well as in enhanced oil and gas recovery. The increasing need to understand the evolution of such coupled processes in subsurface environments has motivated the development of novel experimental approaches, from laboratory to field, which are capable of quantifying the physical, chemical and biological properties of heterogeneous structures at different scales. Detailed experimental investigation and evidence of complex subsurface processes allow testing and validating new measuring techniques, and provide datasets with sufficient resolution to make the validation of coupled processes theories and numerical models possible.
The objective of this session is to discuss novel improvements in our understanding of coupled subsurface processes based on innovative methods allowing the quantification of relevant phenomena and their underlying mechanisms such as the dynamics of single and multiphase flows, conservative and reactive transport, chemically driven or biologically mediated processes, and bacterial dynamics and biofilm growth in heterogeneous porous and fractured media. Contributions may include, for example, experiments featuring high resolution measurements with novel sensors, analytical and imaging techniques, advanced in-situ single- and/or cross-borehole hydraulic tests, (hydro)geophysical techniques, strategies for borehole/borehole interval sealing, or inverse model techniques. We particularly encourage integrative multi-physic methods, i.e. hydraulic, chemical or heat methods aiming at elucidating the heterogeneity of flow, transport and related processes. Ideas for future strategies related to experimental methods, interpretation of existing data, and associated theoretical/numerical modeling, are particularly welcome.

Orals: Mon, 24 Apr | Room 2.15

Chairpersons: Nataline Simon, Yves Meheust, Vittorio Di Federico
Large scale and field studies
08:30–08:40
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EGU23-7325
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On-site presentation
Costanza Cambi, Francesco Mirabella, Marco Petitta, Francesca Banzato, Giulio Beddini, Carlo Cardellini, Davide Fronzi, Lucia Mastrorillo, Alberto Tazioli, and Daniela Valigi

Changes in groundwater flow in response to strong earthquakes are widely described in many tectonic environments. For example, a post-seismic discharge variation is often attributed to an increase of bulk permeability due to co-seismic fracturing and/or to a change in the role of faults in acting as conduits/barrier to groundwater flow.

We take as an example the fractured aquifer of the Mts. Sibillini carbonate massif, in Central Italy, which were affected by a strong and prolonged extensional seismic sequence in 2016-17. The sequence was characterized by an M=6.5 event (mainshock), an M=6 event, an M=5.9 event, up to 60 M>4 events and several M>5 earthquakes. The strongest events caused rupturing of the topographic surface for a cumulative length in the order of 30 km and an important portion of aftershocks occurred at depths where groundwater is stored.

As a response to the seismic sequence, the main NNW-directed groundwater flow was diverted to the west and a discharge deficit was observed at the foot-wall of the activated fault system with a relevant discharge increase, accompanied by geochemical variations, at the fault system hanging-wall.

By integrating geo-structural reconstructions, seismological and ground deformation data, artificial tracer tests results and a 4-years discharge and geochemical monitoring campaign data, we show that the observed groundwater variations are due to a combination of permeability increase along the activated fault systems and hydraulic conductivity increase of the hanging-wall block due to fracturing, extension and subsidence, which determined a fast aquifers emptying. Seismicity temporarily triggered a change of the pre-existing predominant along-faults-strike NNW-SSE oriented regional flow to a west-directed flow, perpendicular to faults strike. We discuss the position of the aquifer with respect to the activated faults and how this affected the observed phenomena.

 

REFERENCE

Cambi, C., Mirabella, F., Petitta, M., Banzato, F., Beddini, G., Cardellini, C., ... & Valigi, D. (2022). Reaction of the carbonate Sibillini Mountains Basal aquifer (Central Italy) to the extensional 2016–2017 seismic sequence. Scientific Reports, 12(1), 1-13. DOI: 10.1038/s41598-022-26681-2

How to cite: Cambi, C., Mirabella, F., Petitta, M., Banzato, F., Beddini, G., Cardellini, C., Fronzi, D., Mastrorillo, L., Tazioli, A., and Valigi, D.: Groundwater flow changes in response to extensional earthquakes: a case study from the 2016-17 seismic sequence in Central Italy, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7325, https://doi.org/10.5194/egusphere-egu23-7325, 2023.

08:40–08:50
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EGU23-6983
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On-site presentation
Rowan Vernon, Laura Burrel, Jon Ford, Richard Haslam, Tom Randles, Dave McCarthy, Mark Woods, and Helen Burke

The Flamborough Head Fault Zone (FHFZ) is a regionally-significant structural zone in northeast England which dissects the Upper Cretaceous Chalk Group, a 500 m thick limestone succession which is a principle aquifer and main source of water supply in the region. The geometry and physical characteristics of the Chalk succession, including the effects of faulting, influence groundwater flow across the region. Consequently, understanding the architecture of the FHFZ is vital to sustainably managing water resources in this area.

The FHFZ marks the southern extent of the Cleveland Basin and the northern margin of the Market Weighton Block and has a complex history of Mesozoic-Cenozoic extension and compression. It is predominantly comprised of east-west trending faults which form a graben that is dissected by north-south trending faults, including the southern extension to the Peak Trough, the Hunmanby Fault. To the west, FHFZ links with the Howardian Fault System and offshore, in the east, it is truncated by the north-south trending Dowsing Fault. The FHFZ is well exposed and described in coastal cliff sections at Flamborough Head but the inland architecture of the faults has hitherto been poorly explored predominantly due to limited inland-exposure.

To address this a multi-faceted approach to geological mapping has been undertaken in the region by the British Geological Survey, in collaboration with the Environment Agency and Yorkshire Water Limited. Remote sensing, targeted field mapping, palaeontological analysis, passive seismic and 2D onshore seismic interpretation have been integrated to understand the inland architecture of the FHFZ in unprecedented detail. Combining these techniques has enabled us to bridge the gap between the surface geology and deeper subsurface structure, increase our understanding of the geology of the region and produce an improved conceptual model at a range of depths which will be used to better manage water resources.

How to cite: Vernon, R., Burrel, L., Ford, J., Haslam, R., Randles, T., McCarthy, D., Woods, M., and Burke, H.: Surface and subsurface mapping of the Flamborough Head Fault Zone to inform groundwater management in the Yorkshire Wolds, UK., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6983, https://doi.org/10.5194/egusphere-egu23-6983, 2023.

08:50–09:00
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EGU23-4868
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On-site presentation
Ting-To Yu and Wen Fei Peng

The fracture density of rock could create the applying shock waves phase difference at the laboratory scale. For using this technology in determining the stress status along the wave propagating path, removing unnecessary noise is the most crucial task. In this study, a machine learning method with Long short-term memory (LSTM) algorithm to retreat the signals from sophisticated seismograms is proposed. The primary analyzing target is data across the 2022 Taitung, Eastern Taiwan seismic event and another micro-seismic data set associated with a surface crack on a hill of Ping-Tong, southern Taiwan. It is found that there is no phase difference among vertical and horizontal components from the same record, when comparing the difference between two various records then the result is distinct. The detecting sub-surface crack density via phase difference has increased in some seismic data pairs of eastern Taiwan after the rupture of the 2022 Taitung earthquake. The machine learning method with LSTM helps to elevate the data retrieval accuracy which cannot be done by conventional Fast Fourier Transformation (FFT). Records from stations adjacent to the hypocenter offer better agreement in phase difference measurement, the higher signal possibly causes it to noise ratio (SNR) in the such neighborhood.

 

Keywords: phase difference, machine learning, LSTM, crack density, stress field

How to cite: Yu, T.-T. and Peng, W. F.: Inverting the Subsurface Fracture Density by Detecting the Phase Difference of Various Seismic wave with Machine Learning, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4868, https://doi.org/10.5194/egusphere-egu23-4868, 2023.

09:00–09:10
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EGU23-12447
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On-site presentation
W. Payton Gardner and Stephen J. Bauer

Noble gas release can be used to investigate the timing, location and magnitude of fracture creation.  Here, a numerical model of gas release and transport, resulting from fracturing events, is used to estimate first-order fracture network characteristics after subsurface detonation.  Released radiogenic noble gases after detonation of three different subsurface explosions of varying source characteristics were interpreted.  A broad suite of gases was sampled from 62 discrete sampling intervals in a 3-D array surrounding the explosion location using an automated field sampling system and a capillary inlet quadrupole mass spectrometer.  Gases analyzed include: 4He, 36,40Ar, 20Ne, N2, O2, NO and CO2/N2O.  Geogenic gas arrivals were observed in a subset of sampling locations.  All geogenic gas arrivals were observed in ports with explosive-derived gas arrivals.  Helium amount and arrival time were used to estimate fracture network damage using a numerical model which allows dynamic changes in fracture aperture, matrix porosity and permeability.  The amount of fracture damage was significantly different between the three different explosions and consistent with other observations of damage.  These results illustrate how geogenic noble gases can be used to understand damage, transport, and fracture creation in fracture networks, with implications for a variety of subsurface topics including hydraulic fracking, mine failure, earthquake and volcanic monitoring.

How to cite: Gardner, W. P. and Bauer, S. J.: Estimating Fracture Network Damage After a Subsurface Detonation Using Geogenic Noble Gases., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12447, https://doi.org/10.5194/egusphere-egu23-12447, 2023.

09:10–09:20
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EGU23-10078
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On-site presentation
Marco Dentz and Jeffrey D. Hyman

We study flow and hydrodynamic transport in spatially random fracture networks.
The flow and transport behavior is characterized by first passage
times and displacement statistics, which show heavy tails
and anomalous dispersion with a strong dependence on the injection
condition. The origin of these behaviors is investigated
in terms of Lagrangian velocities sampled equidistantly along particle
trajectories, unlike classical sampling strategies at a constant rate. The
fluctuating velocity series is analyzed by its copula density, the
joint distribution of the velocity unit scores, which reveals a simple correlation
structure that can be described by a Gaussian copula. This insight
leads to the formulation of stochastic particle motion in terms of a
Klein-Kramers equation for the joint density of particle position and
velocity. The upscaled model captures the heavy-tailed first passage
time distribution and anomalous dispersion, and their dependence on the
injection conditions in terms of the velocity point statistics and
average fracture length. The first passage times and displacement
moments are dominated by extremes occurring at the first step.
The developed approach integrates the complex interaction of flow and structure
into a predictive model for large scale transport in random fracture networks.    

How to cite: Dentz, M. and Hyman, J. D.: Large-scale physics of hydrodynamic transport in random fracture networks, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10078, https://doi.org/10.5194/egusphere-egu23-10078, 2023.

09:20–09:30
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EGU23-9766
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ECS
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On-site presentation
Leonie Bettel, James Fox, Admin Husic, Tyler Mahoney, Arlex Marin, Junfeng Zhu, Ben Tobin, and Nabil Al Aamery

Karst characterizes almost 15% of the worlds terrain, however the mechanics of sediment transport and its prediction in karst river and cave systems remains underdeveloped. Hysteresis analysis has recently been used more to investigate the behaviors of sediments during storm events in surface systems and to some extent in karst systems. Historically, clockwise and counter-clockwise hysteresis typically refer to proximal and distal sourcing for streams. For karst systems, clockwise and counter-clockwise hysteresis has been identified to refer to an saturated and unsaturated aquifer prior to the event.

However, most interpretation of hysteresis assumes a single dominant water source, for example runoff, and assumes that baseflow is not contributing to the sediment load. One aspect of sediment hysteresis and its interpretation that has received less attention is the occurrence of several, significant water sources, eroding and delivering sediment to the watershed outlet. It is common for both surface stream systems  and karst subsurface systems to have multiple water sources contributing to the total sediment load. Each of the sources carries their own sediment time distribution, and often lead to complex hysteresis looping behavior after mixing. The primary goals of this work are to (1) study how the complex source water-sediment mixing processes impact hysteresis results and (2) to carry out solutions to the water-sediment mixing processes for karst streams, caves, and springs and show the utility and uncertainty of the method.

Several high-resolution sensors have collected data at a karst spring in central Kentucky, USA, for a 2.5 year period. Water unmixing was performed using electrical conductivity as a tracer to separate the groundwater from the surface water and infer sediment sources. Theoretical analyses have shown that not only timing and magnitude of sedigraphs influence the result of the hysteresis loops, but also timing and magnitude of each of the multiple water sources have a strong effect on the resulting hysteresis loop. The groundwater flow shows to have dominant counter-clockwise hysteresis loop, surface water shows to have clockwise loops dominating. Depending on the timing and magnitude of the water sources, the hysteresis loop at the karst spring varies from strictly counterclockwise, to a figure-8 loop, to a complex pattern.

How to cite: Bettel, L., Fox, J., Husic, A., Mahoney, T., Marin, A., Zhu, J., Tobin, B., and Al Aamery, N.: Investigating sediment transport in karst using hydrograph unmixing, sediment transport modeling and multi-source hysteresis, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9766, https://doi.org/10.5194/egusphere-egu23-9766, 2023.

09:30–09:40
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EGU23-9396
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ECS
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On-site presentation
Thomas Junique, Raphael Antoine, Stéphane Costa, Bruno Beaucamp, Vincent Guilbert, Cyril Ledun, Olivier Maquaire, Faycal Rejiba, and Cyrille Fauchard

Saltwater wedge is a natural phenomenon defined as the displacement and retention of saltwater in a freshwater aquifer. This saline intrusion can modify the content of dissolved elements in coastal freshwater aquifers, which can have consequences for water use (drinking or agricultural), on the ecology, the environment, the erosion of coasts, and the stability of coastal structures.

This study focuses on the integration and coupled interpretation of various geophysical and optical data obtained on the ground and by drone to evaluate the intrusion of seawater in a coastal chalk cliff in Sainte-Marguerite-sur-Mer in Normandy, France. The objective is to characterize the freshwater-saltwater interface and describe the internal structure of the formation. To do so, the combination of geophysical (Electrical Resistivity Imaging, ERI), aerial (visible and thermal infrared photogrammetry, IRT), and geotechnical (piezometers) methods was adopted.

The ten ERI profiles (transverse and longitudinal to the cliff) allowed for the mapping of the electrical resistivity distribution. The novel contribution of this study was the highlighting of a marine intrusion under the chalk cliffs visualized using transverse ERI profiles implanted directly on the steep dip of the cliff. The use of a 30m deep piezometer positioned on the plateau of the cliff and intersecting the ERI profiles made it possible to constrain the resistivity values to the measured salinity values. The presence of this saltwater wedge was characterized by low resistivity values. The top of the cliff and the parts close to the outcrop showed significant resistivities, indicating a high level of potential damage (cracks in the outcrop, underground cavities). This allowed for the identification of a zone (about 10m before the main scarp) vulnerable to the risk of collapse.

It has been shown that the difference in groundwater density leads to unstable conditions. We propose that the denser saline water covering the less dense freshwater creates a haline convection of the brackish waters at the base of the cliff and at the level of the rocky shore platform. The IRT was used to identify the wet areas of the cliff and the resurgences of the water table on the platform. Finally, all the data were grouped to propose a conceptual model of saline intrusion under the coastal cliffs.

How to cite: Junique, T., Antoine, R., Costa, S., Beaucamp, B., Guilbert, V., Ledun, C., Maquaire, O., Rejiba, F., and Fauchard, C.: Characteristics of saltwater wedge under the chalk cliffs of Sainte-Marguerite-sur-Mer (Normandy, France) using optical and geophysical methods., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9396, https://doi.org/10.5194/egusphere-egu23-9396, 2023.

09:40–09:50
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EGU23-12405
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ECS
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On-site presentation
Steven Reinaldo Rusli, Albrecht Weerts, Syed Mustafa, Dasapta Erwin Irawan, and Victor Bense

Anthropogenic impact on groundwater storage depletion has been detected in many places from catchment to global scales, including in our study area, the Bandung groundwater basin, Indonesia. Groundwater abstraction of various magnitudes, pumped out from numerous depths of aquifers, stimulates different changes in hydraulic heads among vertical subsurface stratifications. Such circumstances generate groundwater movement, where it flows from the upper layer storage to underlying aquifers, referred to as aquifer interaction in this study. Meanwhile, remote-sensing products such as GRACE measure the integrated water storage changes over depth and space, making it difficult to capture and derive the storage internal vertical groundwater fluxes from such signals. As an alternative, environmental water tracers (EWT) have been used to investigate subsurface water movement and to gain a conceptual understanding of groundwater flow dynamics. However, quantitative measurement of the rates of fluxes is not often possible, despite being essential to ensure sustainable groundwater resources management.

In this study, we utilize (a) groundwater flow modeling in conjunction with (b) EWT data to quantify the aquifer interaction driven by multi-layer groundwater abstraction in the Bandung groundwater basin, Indonesia. The available environmental water tracers data include major ion elements (Na+/K+, Ca2+, Mg2+, Cl-, So24-, HCO3-), stable isotope data (d2H and d18O), and groundwater age estimates (radiocarbon/14C content). These measurements are used to qualitatively evaluate the numerical groundwater flow model. The model, forced by recharge calculated using the hydrological model of wflow_sbm, is calibrated by minimizing the difference between the dynamic steady-state simulated and the observed groundwater levels.

We evaluate the groundwater flow model and the EWT-driven analysis from multiple perspectives. The results suggest that the groundwater recharge is uniformly distributed spatially, the groundwater is flowing regionally from the basin periphery inward to the basin’s center following the topographical distribution, and vertical groundwater fluxes are identified. All three deductions, in a qualitative sense, are agreed upon by both the EWT observations and the groundwater flow model. From the groundwater flow model, we quantify that the aquifer interaction is equivalent to, on average, 0.110 m/year, which is highly significant compared to the other groundwater budgets. We also determine the unconfined aquifer storage volume decrease, calculated from the change in the groundwater table, that results in an average declining rate of 51 Mm3/year. This number shows that the upper aquifer storage is dwindling at a rate that is disproportionate to its groundwater abstraction, hugely influenced by the aquifer interaction. The storage lost from only this partition contributes up to 60.3% of the total groundwater storage lost, despite contributing to only 32.3% of the groundwater abstraction. Additionally, we also investigate and examine the correlation between the groundwater level changes and the groundwater abstraction zones. The results of our study confirm that quantification of the aquifer interaction and groundwater level change dynamics driven by multi-layer groundwater abstraction in multi-layer hydrogeological settings is possible by our proposed methods. Applying such methods will assist in deriving basin-scale groundwater policies and management strategies under the changing anthropogenic and climatic factors, thereby ensuring sustainable groundwater management.

How to cite: Rusli, S. R., Weerts, A., Mustafa, S., Irawan, D. E., and Bense, V.: Quantifying aquifer interaction using numerical groundwater flow model evaluated by environmental water tracers data: Application in Bandung groundwater basin, Indonesia, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12405, https://doi.org/10.5194/egusphere-egu23-12405, 2023.

09:50–10:00
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EGU23-10693
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ECS
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On-site presentation
Aymen Nefzi, Daniel Paradis, René Lefebvre, and Olivier Bour

Transport of solutes in aquifers is controlled by the heterogeneous spatial distribution of hydraulic properties, but the characterization of aquifer heterogeneity is quite challenging with conventional methods. Hydraulic tomography (HT) was developed to define the heterogeneous distribution of hydraulic conductivity (K) and specific storage (Ss). HT involves the emission of a series of hydraulic head perturbations in a stressed well and the recording of this signal at several levels in the stressed and observation wells. All recorded hydraulic head responses are simultaneously analyzed through numerical inversion, which provides the spatial distribution of hydraulic properties at a scale relevant for local site investigations.

This communication reports on a tomographic experiment carried out in a heterogeneous and highly anisotropic granular aquifer at the Saint-Lambert research site near Quebec City, Canada. This site has already been the object of detailed characterizations with multiple hydraulic methods: pumping tests, packer slug tests, flowmeter profiles, vertical interference tests, and slug test tomography. A relatively new approach named oscillatory hydraulic tomography (OHT) was tested, in which multi-frequency oscillatory head perturbations are induced in an interval isolated by packers of the stressed well by a submerged rod that is electronically controlled by a winch system. Hydraulic responses are measured in the stressed intervals and in multiple intervals of an observation well.

This study was primarily aimed at testing, first on an operational level, if the OHT signal could be generated in the stressed well and propagated to the observation well in a highly anisotropic granular aquifer. Second, the study developed a rigorous workflow for the treatment of the measured hydraulic heads. Third, in terms of characterization efficacy, the study aimed to determine if multiple controlled frequencies would allow the assessment of K spatial distribution.

Results show that the field experiment provided clear measured hydraulic responses that could be used to obtain the 2D distribution of hydraulic properties from the inversion of OHT measurements. Comparison was made of inversion results using a single oscillatory frequency and multiple frequencies. Under conditions of realistic field measurement noise and uncertainty, it will be valuable in future work to compare the imaging capabilities of oscillatory hydraulic tomography against other tomographic methods. Further investigation is also needed to examine the information content of oscillatory hydraulic tomographic data for characterizing K and Ss heterogeneities through a sensitivity and resolution analysis. This study demonstrates the practical potential for the implementation of OHT experiments in relatively low permeability and highly anisotropic granular aquifers.

How to cite: Nefzi, A., Paradis, D., Lefebvre, R., and Bour, O.: Data acquisition and processing of multi-frequency oscillatory hydraulic tomography in a granular aquifer, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10693, https://doi.org/10.5194/egusphere-egu23-10693, 2023.

10:00–10:10
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EGU23-13617
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solicited
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On-site presentation
Juan J. Hidalgo, Benjamín Piña, Cristina Valhondo, Claudia Sanz, and Marta Casado

Managed aquifer recharge (MAR) sytems based on water filtration allow to improve recharged water quality and quantity by retaining suspended particles and microorganisms. However, the periodic detection in groundwater of pathogens and other microorganisms that represent a significant risk for human health makes it necessary to study the mechanisms affecting the propagation and fate of microbial populations during the process.

In this work a series of column experiments were performed to characterize bacteria transport in porous media. Two type of columns were built. One using only sand and another using a combination of sand, compost and wood chips. In each column a punctual injection of tracers (rhodamine and amino-G acid) and bacteria consortium collected from the effluent of a wastewater treatment plant were injected. Samples of column outflows were collected to obtain breakthrough curves of the tracers and the different amplicon sequence variants (ASVs) of bacteria to determine the material influence on the retention of bacteria. Bacteria displayed a strong anomalous behavior with late arrival peaks and longer tails than those obtained with the tracers.

A continuous time random walk (CTRW) transport model was developed to interpret the experimental results. The model characterizes transport in terms of mobile-immobile domains. Bacteria are transported with the mean flow and experience transitions from and to low mobility zones with a certain frequency. Transport is described in terms of four parameters, namely, the mean flow velocity, the dispersion coefficient, the trapping rate, and the mean residence time in the immobile zones. The model was able to reproduce satisfactorily the observed breakthrough curves of over 470 measured ASVs. The analysis of the breakthrough curved determined that bacteria form two clusters. The breakthrough curve of one cluster has heavy tails and it is formed by small, motile, gram-negative bacteria. The other cluster displays strong peaks and a relatively weaker tailing. CTRW parameters are able to predict the cluster in which a certain bacteria belongs.

How to cite: Hidalgo, J. J., Piña, B., Valhondo, C., Sanz, C., and Casado, M.: Stochastic modeling of bacterial transport and retention during aquifer artificial recharge, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13617, https://doi.org/10.5194/egusphere-egu23-13617, 2023.

Small scale experimental and theoretical studies
Coffee break
Chairpersons: Oshri Borgman, Pietro De Anna, Yves Meheust
10:45–10:55
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EGU23-4020
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ECS
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solicited
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On-site presentation
Marcel Moura, Paula Reis, Gerhard Schäfer, Renaud Toussaint, Eirik Grude Flekkøy, Per Arne Rikvold, and Knut Jørgen Måløy

The standard liquid transport processes in porous media happens through a network of interconnected pore bodies and pore throats (here called the primary network). When a non-wetting phase displaces a wetting phase from a porous sample (drainage), thin films of the wetting phase are bound to be left on the surface of the constituting grains (for example when air displaces water from a porous rock, thin films of water are left behind, covering the rock grains). Under certain conditions, isolated liquid films can eventually merge, forming a secondary network of interconnected films and capillary bridges (see red arrows in the figure) that can effectively enhance the overall connectivity of the medium and act as a new pathway for fluid transport. We have performed experiments using transparent networks with the objective of studying transport processes that are enhanced by film flow. Our setup allow us to directly visualize the secondary network in the sample and we have shown how fluid bodies that are not linked via the primary network can actually be connected via the secondary network. This connection has important consequences for processes such as the dispersion of pollutants in soils and the transport of nutrients to plants in arid regions.

 

 

References

Moura, E. G. Flekkøy, K. J. Måløy, G. Schäfer and R. Toussaint, “Connectivity enhancement due to film flow in porous media,” Phys. Rev. Fluids 4, 094102 (2019).

Moura, K. J. Måløy, E. G. Flekkøy, and R. Toussaint, “Intermittent dynamics of slow drainage experiments in porous media: Characterization under different boundary conditions,” Front. Phys. 7, 217 (2020).

How to cite: Moura, M., Reis, P., Schäfer, G., Toussaint, R., Flekkøy, E. G., Rikvold, P. A., and Måløy, K. J.: Thin film flow: fluid transport via thin liquid films in slow porous media flows, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4020, https://doi.org/10.5194/egusphere-egu23-4020, 2023.

10:55–11:05
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EGU23-14697
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On-site presentation
John Koestel, Anna Schwenk, Nick Jarvis, and Mats Larsbo

Macropores have important beneficial impacts on the hydrological cycle, since they reduce risks of waterlogging, surface runoff, soil erosion and flooding. On the other hand, macropore flow is also associated with significant ecosystem disservices, since it can dramatically accelerate the leaching of contaminants to surface water and groundwater. Several approaches to model preferential macropore flow have been developed. One approach is to use the kinematic wave equation, in which the kinematic exponent should depend on the exponent in a power law relationship between wetted macropore surface area and macropore saturation. Most model applications have relied on calibration of model parameters against measured data on water flow. This makes critical testing of the underlying model concepts difficult and raises the question of whether the model is matching the data for the right reasons or not. In this study, we used X-ray tomography to quantify water and air distributions in macropores at varying steady-state flow rates in two topsoil and two subsoil columns (diameter 9 cm) sampled from a clay soil. We collected sufficient data to derive the kinematic wave exponent from the image data for the two topsoil samples. We found that the wetted macropore surface area and macropore saturation were indeed related by a power law for the first three irrigation intensities, corresponding to kinematic exponents of 1.22 and 1.26, respectively. These promising results need to be verified in future experiments that should be conducted on soil samples with smaller diameters to achieve better image resolutions and signal-to-noise ratios.

How to cite: Koestel, J., Schwenk, A., Jarvis, N., and Larsbo, M.: Quantitative three-dimensional imaging of macropore flow in undisturbed soil under different irrigation intensities, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14697, https://doi.org/10.5194/egusphere-egu23-14697, 2023.

11:05–11:15
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EGU23-15772
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On-site presentation
Andrea Carminati, Pascal Benard, and Peter Lehmann

Plant roots and bacteria release in soils polymeric blends of substances which alter the physics of soil water flow and support life in soils. They adsorb water, decrease the surface tension of the soil solution and increase its viscosity, and, more generally, they change the soil solution into a non-Newtonian liquid with viscoelastic properties. A theory of drying of polymer solutions in porous media is missing and it is needed to understand the feedback between physics of porous media and life in soils. It was observed that during drying polymer solutions are deposited as thin surfaces spanning multiple pores and that these depositions are associated with a decrease in evaporation rate. Here, we provide a physical explanation of surface formation. The modeling framework includes Darcian flow across the polymeric network driven by a gradient in water potential. As the polymer dries and air invades the pore space the polymer network is stretched. The stretching causes a stress in the polymer network that alters the relation between water potential and polymer concentration: the more stretched is the polymer network the smaller is the spacing between the polymers at a given water potential, and the lower is the permeability of the network. The model predicts that at a critical point during evaporation there is an asymptotic increase in polymer concentration at the gas-gel interface corresponding to the deposition of solid-brittle interfaces. The onset of this glass transition depends on flow rate and pore size, with earlier deposition for fast high evaporative fluxes and small pores. The model explains why evaporation is suppressed much earlier and more significantly when the polymer solution dries into a porous medium, in comparison to the case when the polymer solution is free to dry outside a porous medium.

How to cite: Carminati, A., Benard, P., and Lehmann, P.: Theory of drying of polymer solutions in porous media, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15772, https://doi.org/10.5194/egusphere-egu23-15772, 2023.

11:15–11:25
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EGU23-2274
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ECS
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Virtual presentation
Ilan Ben-Noah, Juan J. Hidalgo, Joaquin Jimenez-Martinez, and Marco Dentz

We study the upscaling of pore-scale solute transport in partially saturated porous media at different saturation degrees. The interaction between structural heterogeneity, phases distribution and small-scale flow dynamics induces complex flow patterns and broad probability distributions of flow. In turn, this spatial distribution of flow velocities, at the pore scale, induces irregular (non-Fickian) transport of dissolved substances (e.g., contaminants), causing an earlier arrival and longer tailing, which may have grave consequences in underestimating risk assessments and prolonged cleanup times of contaminated sites.

Here, we suggest an integrated continuous time random walk (CTRW) modeling framework, which accounts for also the entrapping of particles in zones of low flow velocities, to estimate the resident times of solutes in the media. Furthermore, comparing the results of the CTRW model to a well-established numerical simulation method allows a phenomenological evaluation of the model's physical parameters for different conditions (i.e., volume of entrapped air, mean water flow rate, or solute molecular diffusion coefficient).   

In this study we show that entrapped air promotes preferential solute transport and solute trapping in low flow regions. Moreover, we demonstrate that the trapping frequency and trapping time depend on the interaction between advection and diffusion (i.e., the Péclet number). An integrative CTRW model captures the effects of trapping in stagnant regions and preferential transport on non-Fickian dispersion of solutes.

How to cite: Ben-Noah, I., Hidalgo, J. J., Jimenez-Martinez, J., and Dentz, M.: Evaluating solute-Trapping Induced Non-Fickian Transport in Partially Saturated Porous Media, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2274, https://doi.org/10.5194/egusphere-egu23-2274, 2023.

11:25–11:35
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EGU23-17037
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On-site presentation
Pratyaksh Karan, Uddipta Ghosh, Yves Méheust, and Tanguy Le Borgne

Reaction fronts are widespread in nature and are encountered frequently in the geological context. Examples include contaminant spread, neutralization-based reservoir decontamination, biogeochemical phenomena, and many more. The complex porous structures of subsurface formations renders the flow geometry incredibly complex, which in turn can, and often does, lead to interesting and peculiar reactive transport. For instance, the stretching and folding of the reaction front due to flow shear can enhance the effective reactivity, and flow stagnation spots can serve as sites for accummulation of reactants.

At the Darcy scale, the spreading of the front is controlled by hydrodynamic dispersion, which is a continuum scale manifestation of the pore scale interaction between heterogeneous advection and molecular diffusion. When the flow field is uniform, the consequence of dispersion is only a quantitative enhancement of diffusion. However, if the flow field varies in space, as may occur for example during aquifer remediation by injection of a neutralizing agent, the effect of hydrodynamic dispersion will lead to qualitative modifications in reactive transport dynamics as compared to hypothetic scenarios where the only diffusive mechanism is molecular diffusion. Yet, despite the ubiquity of dispersion, its impact on reactive fronts in porous media has not been addressed for flows with an axisymmetrical geometry, which are typical of well injection scenarios.

Therefore, we study the impact of hydrodynamic dispersion on reactive transport in cylindrically-advected bimolecular reaction fronts. We show that, in the reaction-limited regime at early times, mechanical dispersion is the dominant transport process and augments the reaction front’s advancement (which scales as t1/3, t being the time), the reaction rate (which scales as t2/3) and the product mass (which scales as t5/3), in comparison to a dispersion-free scenario (for which, the reaction front advancement, the reaction rate and the product mass scale as t1/2, t1 and t2 respectively). On the other hand, depending on the strength of hydrodynamic dispersion, we may encounter a dispersion-dominated, mixing-limited, regime of the reactive front at large times, which exhibits a declining reaction rate. This bevahior is significantly different from the dispersion-free scenario where a declining reaction rate is never encountered. Lastly, at sufficiently long times (longer for stronger dispersion), the reaction front transitions to a behavior akin to that seen in the dispersion-free scenario, wherein the differences between the dispersive and the dispersion-free scenarios become negligible.

How to cite: Karan, P., Ghosh, U., Méheust, Y., and Le Borgne, T.: Early Time Effective Reactivity of Reactive Transport in Cylindrically-Advected Reaction Fronts is enhanced by Hydrodynamic Dispersion, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17037, https://doi.org/10.5194/egusphere-egu23-17037, 2023.

11:35–11:45
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EGU23-16451
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ECS
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On-site presentation
Filippo Miele, Janis Patino, and Veronica Morales

Fate and transport of colloids and bio colloids in structurally heterogeneous porous media are known to exhibit anomalous behaviours such as non-Gaussian breakthrough curves. Classical approaches, like Colloid Filtration Theory, relies on spatial averaged quantities, neglecting flow topology heterogeneity brought about by both local pore scale surface irregularities and broad pores size distribution: two potential triggers for super diffusive effects and broad trapping time distributions. Recent theoretical work has tried to address these deficiencies by modeling deposition and flow variations as stochastic processes (Miele et al., Phys. Rev. Fluids 2019; Bordoloi et al., Nat. Commun. 2022). However, experimental evidence to demonstrate its validity for 3D geologic structures is still lacking. We thus design a novel experimental set-up to assess colloid fate transport under realistic structural heterogeneity with controlled laboratory conditions. Heterogeneous pore structures are first obtained from X-ray tomography of field samples and are subsequently 3D-printed at high resolution. Column transport experiments with gold (Au) nanoparticles are then conducted at different flow regimes, from which effluent concentration (at the macro scale) and colloid deposition (at the pore scale) are collected. These empirical data are complemented with pore network analysis that parametrizes the co-presence of preferential channels and stagnant cavities and, further, validates the stochastic model of interest. The findings shed light on the main drivers and structural hotspot for colloid filtration in realistic porous media.

How to cite: Miele, F., Patino, J., and Morales, V.: Surface Induced Anomalous Transport of Nanoparticle in 3D Printed Structurally Heterogeneous Soils: coupling experiments and stochastic models, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16451, https://doi.org/10.5194/egusphere-egu23-16451, 2023.

11:45–11:55
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EGU23-17293
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On-site presentation
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Mamta Jotkar, Ilan Ben-Noah, Juan J. Hidalgo, Marco Dentz, and Luis Cueto-Felgueroso

Diffusiophoresis referring to the colloidal particle migration triggered by gradients of local salt concentration, has been established in the recent years as an efficient particle manipulation tool in relatively simple microfluidic setups such as plane channels, dead-end pores, Y-shaped channels, vertical diverging pores, etc. Owing to the fact that the particle velocities depend logarithmically on the solute concentration gradients, small variations in the concentration fields can result in significantly large diffusiophoretic particle motion. However, despite the recent investigations hardly anything is known about its effects in the field of flow and transport in porous media. Spatial heterogeneities and complex fluid-phase distributions are quite ubiquitously found across spatial scales ranging from pore-scale to field-scale. These have a strong impact on the flow and transport of dissolved solutes through porous media giving rise to rich heterogeneous solute landscapes that provide local gradients of solute concentration, a prerequisite for diffusiophoretic motion. Following this motivation, we perform pore-scale simulations to understand the effects of diffusiophoresis at pore-scale in partially saturated media for varying degrees of fluid saturation and quantify their impact on the macroscopic particle transport. We envision that by exploiting the heterogeneous solute landscapes, particle motion can be controlled in an efficient manner. Depending on the sign of the diffusiophoretic mobility, determined by the size and surface charge of the colloidal particle, localized particle entrapment or removal can be achieved systematically. Our results that are pioneer in the field of diffusiophoretic transport through porous media, will pave the way to attaining controlled particle manipulation through porous media. 

How to cite: Jotkar, M., Ben-Noah, I., Hidalgo, J. J., Dentz, M., and Cueto-Felgueroso, L.: Controlling colloid transport through porous media via local gradients of solute concentration, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17293, https://doi.org/10.5194/egusphere-egu23-17293, 2023.

11:55–12:05
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EGU23-17055
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ECS
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Virtual presentation
|
Niloy De, Naval Singh, Remy Fulcrand, Yves Méheust, Patrice Meunier, and François Nadal

Convective dissolution is a perennial trapping mechanism of carbon dioxide in geological formations saturated with an aqueous phase. This process, which couples dissolution of supercritical CO2, convection of the liquid containing the dissolvedCO2, and mixing of the latter within the liquid, has so far not been studied in two-dimensional porous media. In order to do so, two-dimensional (2D) porous micromodels (patterned Hele-Shaw cells) have been fabricated from UV-curable NOA63 glue. NOA63 is used instead of PDMS, which is permeable to CO2 and does not allow for a controlled no flux boundary condition at the walls. The novel fabrication protocol proposed here, based on the bonding of a patterned photo-lithographed NOA63 layer on a flat NOA63 base, shows good reproducibility regardless of the pattern’s typical size, and allows for easy filling of the cell despite the small value of the gap. A pressure chamber allows pressurizing the CO2 and outside of the flow cell up to 10 bars. Experiments were performed in 11 different porous media geometries. As expected, a gravitational fingering instability is observed upon injection of gaseous carbon dioxide in the cell, resulting in the downwards migration of dissolved CO2 plumes through the 2D porous structure. The initial wavelength of the fingers is larger in the presence of a hexagonal lattice of pillars. This effect can be correctly predicted from the theory for the gravitational instability in a Hele-Shaw cell devoid of pillars, provided that the permeability of the hexagonal porous medium is considered in the theory instead of that of the Hele-Shaw cell. Fluctuations around the theoretical prediction observed in the data are mostly attributed to a hitherto unknown weak locking of the wavelength on the distance between closest pillars.

How to cite: De, N., Singh, N., Fulcrand, R., Méheust, Y., Meunier, P., and Nadal, F.: Convective dissolution of carbon dioxide in 2D water-saturated porous media: an experimental study in two-dimensional micromodels, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17055, https://doi.org/10.5194/egusphere-egu23-17055, 2023.

12:05–12:15
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EGU23-17523
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ECS
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On-site presentation
Shabina Ashraf, Jayabrata Dhar, François Nadal, Patrice Meunier, and Yves Méheust

A large fraction of greenhouse gases (about 60%) released into the atmosphere are due to CO2 emissions from industrial processes and the burning of fossil fuels [1]. One of the strategies employed to reduce the emissions is rapping them securely in the subsurface [2-4]. Dissolution trapping, in particular, involves injection of CO2 into the subsurface where the supercritical CO2 (sCO2) dissolves in the aquifer brine and forms a CO2 enriched layer within solution. The interface between the high density CO2 rich brine on the top and the ambient low density aquifer water below results in destabilization of the aforementioned layer [2-4]. This leads to a gravitational instability which then causes a natural convection of CO2 rich brine to lower layers, thereby accelerating further dissolution of the sCO2 into the fresh brine.

The study of Brouzet et al. shows that traditional continuume scale, Darcy law-governed, models underestimate the timescales of the convective dissolution’s dynamics, owing to local heterogeneity in the pore-scale flow, and that it may thus be necessary to take pore-scale fluctuations into account [5]. We present here a 2D experimental study using miscible analog fluids with a contrast in densities to understand the convective transport of the dissolved sCO2. The fluids and the granular media are refractive index matched, which renders the medium transparent and helps in accurate quantification of experimental findings at various Rayleigh (Ra) and Darcy numbers (Da). Darcy scale simulations are used to complement the two-dimensional experimental measurements and it was found that Darcy scale simulations underpredict the experimental findings by several orders of magnitude, which is consistent with the findings by Brouzet et al. We investigate convective dynamics for various values of the number by changing the density of fluids, the properties of the granular medium (permeability, size of the granular medium) which determines the size of the instability with respect to pore size. When that number is much smaller than 1, obvious causes for the failure of the continuum scale description can be excluded, yet discrepancies remain between the experimental results and the simulations.

References:

[1] Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, IPCC 2014.

[2] Emami-Meybodi, H., Hassanzadeh, H., Green, C. P., & Ennis-King, J. (2015). Convective dissolution of CO2 in saline aquifers: Progress in modeling and experiments. International Journal of Greenhouse Gas Control, 40, 238-266.

[3] Pau, G. S., Bell, J. B., Pruess, K., Almgren, A. S., Lijewski, M. J., & Zhang, K. (2010). High-resolution simulation and characterization of density-driven flow in CO2 storage in saline aquifers. Advances in Water Resources, 33(4), 443-455.

[4] Meunier, P., & Nadal, F. (2018). From a steady plume to periodic puffs during confined carbon dioxide dissolution. Journal of Fluid Mechanics, 855, 1-27.

[5] Brouzet, C., Méheust, Y., & Meunier, P. (2022). CO2 convective dissolution in a three-dimensional granular porous medium: An experimental study. Physical Review Fluids, 7(3), 033802.

How to cite: Ashraf, S., Dhar, J., Nadal, F., Meunier, P., and Méheust, Y.: Experimental characterization of Rayleigh-Taylor convection in granular media for CO2 sequestration by dissolution trapping, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17523, https://doi.org/10.5194/egusphere-egu23-17523, 2023.

12:15–12:25
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EGU23-15397
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On-site presentation
Vittorio Di Federico, Alessandro Lenci, and Sepideh Majdabadi Farahani

The displacement of one fluid by another in porous media is of interest in reservoir engineering, groundwater remediation, and subsurface heat recovery. In several instances, i.e. in coarse or macro porous media, or in heavily fractured rocks, the threshold Reynolds number is exceeded and inertial effects cannot be neglected. Consequently, the Forchheimer extension of Darcy’s law describes the motion, and a novel quantity, the Forchheimer or inertial coefficient, enters the picture, entailing implications on several coupled phenomena. We study plane gravity currents propagating in a homogeneous porous medium of given permeability saturated with a lighter fluid, but results are also valid for the displacement of a heavier ambient fluid (brine) by a lighter one advancing below the roof of a porous layer such as in CO2 injection. The injected fluid volume is given by a global conservation of mass and varies as a power-law function of time. Under the lubrication approximation, the pressure gradient is hydrostatic and the one-dimensional transient problem governing the current depth, when expressed in dimensionless form, depends uniquely by a pure number equal to the combination of a Reynolds number multiplied by a Forchheimer number and divided by the square of a densimetric Froude number. We explore the two limit cases of dominating inertial effects or prevailing viscous effects and demonstrate that in both cases the governing equations are amenable to a semi-analytic similarity solution governed by the aforementioned pure number. For a current with constant volume, the solution takes a closed form. 

How to cite: Di Federico, V., Lenci, A., and Majdabadi Farahani, S.: Forchheimer gravity currents in porous media, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15397, https://doi.org/10.5194/egusphere-egu23-15397, 2023.

Posters on site: Mon, 24 Apr, 16:15–18:00 | Hall A

Chairpersons: Vittorio Di Federico, Yves Meheust, Nataline Simon
A.153
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EGU23-2141
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ECS
Yeonguk Jo, Yoonho Song, and Sehyeok Park

Extended leak-off test (XLOT) is one of the in-situ tests, routinely conducted to evaluate integrity of the cased and cemented wellbores during deep borehole drilling, as well as in situ hydraulic properties at a casing shoe depth.

We introduce results of the XLOT conducted in a large diameter borehole, which is drilled for installation of deep borehole based geophysical monitoring system to monitor micro-earthquakes and fault behavior of major linearments in the subsurface. The borehole was planned to secure a final diameter of 200 mm (or more) at a depth of ~1 km deep, with 12" diameter wellbore to intermediate depths, and 7-7/8" (~200 mm) to the bottom hole depths.

We drilled first the 12" diameter borehole to approximately 504 m deep and installed API standard 8-5/8" casing, then cemented the annulus between the casing and bedrock. Then we carried out the XLOT, for several purposes such as confirming casing and cementing integrity, as well as estimating in-situ stress and hydraulic conductivity at the casing shoe depth. To that end, we drilled 4 m length interval to directly inject water and pressurize into the rock mass using the upper API casings. During the XLOT, we recorded flow rates and interval pressures in real time. Based on the logs, we tried to analyze hydraulic conductivity of the test interval, and compare the results with previously reported hydraulic properties measured in other ways.

How to cite: Jo, Y., Song, Y., and Park, S.: Estimating hydraulic conductivity using extended leak-off test conducted during drilling large-diameter borehole, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2141, https://doi.org/10.5194/egusphere-egu23-2141, 2023.

A.154
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EGU23-3285
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ECS
Dahye Kim and In Wook Yeo

Experimental observation and measurement are essential to fundamentally understanding the processes that govern fluid flow and mass transport in rough-walled fractures. The micro-PIV (micro-Particle Image Velocimetry) technique has been introduced for flow visualization inside microscale rough-walled fractures. However, the methodology for mass transport visualization has yet to be established, which is crucial for the analysis/quantification of mass transport and dispersion in rough-walled fractures. This study presented the improved micro-PIV technique to visualize mass transport and measure solute concentration in rough-walled rock fractures. Calibration processes for determining the solute concentration from the measured fluorescence intensity were presented, and measured concentrations were applied to the solute transport and dispersion analyses to validate the measurement technique. The microscopic imaging and analysis demonstrated the transition from macrodispersion to Taylor dispersion-dominant transport. As the fluid velocity increased, higher concentration gradients occurred across the fracture aperture, enabling the solute to break through rapidly along the main flow channel in the middle of the fracture aperture. We successfully visualized channelized solute transport associated with eddies that accounts for Taylor dispersion and non-Fickian transport. This technique enables phenomenon-based experimental research on fluid flow and solute transport in microscale rock fractures, which used to remain in the realm of numerical simulations. Our improved visualization technique will contribute to experimentally elucidating mass transport processes in rough-walled rock fractures.

How to cite: Kim, D. and Yeo, I. W.: Microscopic imaging technique for solute transport in rough-walled rock fractures using micro-PIV, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3285, https://doi.org/10.5194/egusphere-egu23-3285, 2023.

A.155
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EGU23-3033
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ECS
Gumilar Utamas Nugraha, Chuen-Fa Ni, and Thai Vinh Truong Nguyen

The Choushui River Alluvial Fan (CRAF) is facing serious land subsidence problems. In recent years, the main subsidence areas have gradually moved inland, causing security issues for the Taiwan High-Speed Rail (THSR) in the Yunlin county. Although pumping groundwater along the high-speed railway is forbidden, the problem of sinking land has remained. The causes of land subsidence can be multiple and complex. There are discussions about the causes of land subsidence in the Chousui River Alluvial Fan. This study aimed to develop a hydromechanical land subsidence model in this groundwater basin. The modeling process is divided into two broad parts: the groundwater flow model and the hydromechanical/land subsidence model. The development of the model was focused on the severe area of land subsidence in this basin; for this situation, the so-called “site specific model” was developed. Another reason this study used the site-specific model is that the Taiwan government has installed an integrated land subsidence monitoring system in the severe area, including Multilevel Compacting Well (MLCW), GNSS, and Groundwater observation well. This abundant data can be used when calibrating the groundwater flow and mechanical model. The modeling process starts with the construction of site-specific conceptual modeling derived from the basin scale conceptual modeling. This process revealed that the site consists of four aquifers and four aquitard layers with various thicknesses. The next process was creating a numerical groundwater model that began with creating a grid of the model domain. The model consists of fifty rows and fifty columns with ten by-ten meter grid cells and eight layers representing four aquifers and four aquitards. For perimeter boundary conditions, the model has specified head boundary conditions on the east and west part and no-flow boundary conditions on the north, south, and bottom of the model. the hydraulic and mechanical for the initial input of the model were generated using the previous study in this basin. Groundwater flow calibration processes were done using the PEST package. The model was evaluated using a multi-criteria performance meter: R-squared, root mean squared error (RMSE), mean absolute error (MAE), and Nash Sutcliffe Error (NSE). The calibration process for the groundwater flow model shows an excellent result for both mechanical and groundwater flow. The next step is modeling simulated subsidence using scheduling pumping using a different pumping rate scenario. This simulation aimed to reduce subsidence using calibrated pumping rate value but the difference in time of pumping. The result shows a significant subsidence reduction with scheduling pumping in a certain well. Any stakeholder can consider this result to reduce subsidence in the Chousui River Alluvial Fan.

How to cite: Utamas Nugraha, G., Ni, C.-F., and Vinh Truong Nguyen, T.: Land subsidence induced by groundwater withdrawal: from conceptual model to Hydromechanical model in Chousui River Alluvial Fan, Taiwan, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3033, https://doi.org/10.5194/egusphere-egu23-3033, 2023.

A.156
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EGU23-4701
Dugin Kaown, Dong-Chan Koh, Jaemin Lee, Jaeyoun Kim, and Kang-Kun Lee

Environmental tracer data were applied to assess chemical signatures of deep fluid in the fault zones in the southeastern part of South Korea. After MW 5.5 Pohang Earthquake in November 2017, hydrogeochemical and environmental tracer data from groundwater samples around epicenter were monitored from 2017 to 2021. Monitoring wells significantly responded to the earthquakes were selected to evaluate temporal variations of environmental tracer data in the groundwater system. The southeastern part of South Korea shows a distinctive NNE-directed geomorphological feature with several strike-slip fault systems and two wells are closely located to this fault. One monitoring station, KW5, is closely located to the Ulsan Fault, which is a reverse. 3He/4He was slightly increased in most of groundwater samples from monitoring wells after MW 5.5 Pohang Earthquake, while 3He/4He decreased in some groundwater samples from wells around reverse fault (Ulsan fault). Especially, 3He/4He in the wells of KW5 station closely located to the Ulsan Fault considerably decreased after the earthquake. However, the concentrations of Na, Ca, SO4 and HCO3 increased around wells in Ulsan Fault after the earthquake. In this study, the response of aquifer system after earthquakes was compared to assess the differences in chemical changes of fluid around strike-slip and reverse faults using hydrogeochemical and environmental tracer data.

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2022R1A5A1085103).

How to cite: Kaown, D., Koh, D.-C., Lee, J., Kim, J., and Lee, K.-K.: Evaluating groundwater responses to earthquakes using hydrological and environmental tracer data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4701, https://doi.org/10.5194/egusphere-egu23-4701, 2023.

A.157
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EGU23-6813
Chuen-Fa Ni, I-Hsien Lee, Gumilar Utamas Nugraha, and Thai Vinh Truong Nguyen

Accurate assessment of groundwater resources relies on sufficient measurements and efficient analysis tools. The integrated technologies and multidisciplinary knowledge of groundwater have enhanced the understanding of dynamics in groundwater systems. Taking advantage of wide developments in computer sciences and web services, the web platform provides an excellent open environment for groundwater investigations. Most groundwater-relevant web platforms are mainly focusing on data visualization. The data, such as points, polylines, polygons, and pre-analysis results (i.e., the figures) overlap a street map to indicate the locations of interest and quantify the influenced regions of groundwater hazards. Such a one-way interaction framework has significantly limited the implementations of measurement data and groundwater-relevant applications. The study aims to develop an online web-based platform for groundwater data visualization, temporal and spatial data analysis, mesh generation and flow modeling. The study integrates multiple program languages to bridge the data flow and online visualization. The interactive real-time web environment enables users to screen temporal and spatial measurements on the web map, conduct online data analyses, and develop numerical groundwater models. With a well-designed database and numerous modules for data analyses and modeling, the platform allows users to share data and develop collaborative activities. The built-in analysis tools can also improve the efficiency of groundwater management and decision-making processes.

How to cite: Ni, C.-F., Lee, I.-H., Nugraha, G. U., and Nguyen, T. V. T.: An interactive map platform for groundwater data visualization and real-time numerical modeling, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6813, https://doi.org/10.5194/egusphere-egu23-6813, 2023.

A.158
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EGU23-7646
Animesh Nepal, Marco Dentz, Juan J Hidalgo, Jordi Ortin, and Ivan Lunati

During imbibition, fluid-fluid interface at the inlet of a constriction experiences an increase in capillary force that results in rapid fluid invasion known as Haines jump. During drainage, the interface gets pinned at the end of the constriction, which causes p-s trajectories to follow different paths during imbibition and drainage resulting in p-s hysteresis. In this work, we performed quasistatic two-phase flow experiments and simulations of cyclic imbibition and drainage to have a quantitative understanding of pore-scale processes resulting in pressure-saturation (p-s) hysteresis. We considered two different 2D Hele-Shaw cell setups: a capillary tube with a horizontal constriction (ink-bottle) and a heterogeneous porous media randomly populated by cylindrical obstacles. In both setups, drainage and imbibition were driven by quasitatically changing the pressure gradient between the inlet and the outlet of the domain. The experimental results were compared with the results from numerical model in OpenFOAM, which solves the Navier-Stokes equations employing volume of fluid method to calculate the position of the interface and the continuum surface force model to describe surface tension. For the ink-bottle setup, we observed that multiphase flow through a single constriction displayed the signature trait of p-s hysteresis, which depends innately on the cross-section gradient. The steeper the cross-section gradient, the more pronounced the p-s hysteresis, moreover, p-s hysteresis did not occur below a critical gradient. We derived an analytical solution to calculate the critical gradient and compared it with the critical gradient obtained from experiments and simulations. In heterogeneous porous media setup, we observed rapid fluid invasion and retention patterns in small pores during imbibition-drainage cycles, which give rise to hysteretic p-s trajectories. This comparative study will allow us to quantitatively link the pore-scale capillary physics to large-scale p-s hysteresis.

How to cite: Nepal, A., Dentz, M., Hidalgo, J. J., Ortin, J., and Lunati, I.: Experimental and simulation study of quasistatic capillary rise resulting in pressure-saturation (p-s) hysteresis, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7646, https://doi.org/10.5194/egusphere-egu23-7646, 2023.

A.159
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EGU23-7850
Qian Zhang and Yanhui Dong

Nanoparticles (NPs), especially nanoscale zero-valent iron (nZVI) particles, have been extensively used to directly treat contaminated zones in aquifers because of their desirable properties, i.e., high specific surface area and potential mobility. Understanding the transport of nZVI particles, through water-saturated porous media has important implications for many natural and engineered systems. For the first time, we used spin-echo single point imaging (SE-SPI) of low-field Nuclear Magnetic Resonance (LF-NMR) to monitor nanoparticle transport through a heterogeneous porous medium. The ability of this method to provide information of nano- to micro-scale pore structure and to monitor transient processes is verified by a transport experiment using modified nZVI particles. Experimental observations, including (i) the more rapid migration of the front relative to bulk transport of the injected solution of NPs and (ii) the retention of NPs, with 27% of the iron retained at the conclusion of deionized water flushing, highlight the important controls of complex pore structure on the resulting retardation, attenuation and efflux of NPs. Complementary numerical simulations evaluate sample heterogeneity and its effects on local transport properties. In general, the model considering four regions of distinct porosities shows improved performance, as highlighted by the low overall residual sum of squares (0.041 to 0.138), compared to another model assuming a homogeneous pore structure (0.044 to 0.328). Overall, SE-SPI imaging is shown to be an important tool in refining transport processes of NPs in heterogeneous porous media with application to constrain complex natural systems. 



How to cite: Zhang, Q. and Dong, Y.: High-resolution characterization of nanoparticle transport in heterogeneous porous media via low-field nuclear magnetic resonance, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7850, https://doi.org/10.5194/egusphere-egu23-7850, 2023.

A.160
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EGU23-13937
Victor Bense, Luka Nie, and Jacob Oosterwijk

Knowledge of the saturated hydraulic conductivities of aquitards in provisional groundwater abstraction sites is essential to assess the sustainability of future water production. The subsurface of the site in the southwest of The Netherlands has a simple layer cake stratigraphy. Temperature-depth profiles in 12 boreholes were measured and analysed to infer vertical fluxes across an aquitard at a depth (~100 m) below where the impact of recent surface warming could be detected. Hence, the analytical mathematical solution for coupled groundwater-heat flow described by Bredehoeft & Papadopulos in 1965 could be be employed for this purpose. The selection of the depth interval for the aquitard for which the solution is applied, is guided by scanning through the TDP to find depth-intervals for which both a low RMSE between observed temperature and solution is obtained as well as a high Peclet number indicative of significant vertical groundwater flow. Through comparison of the depth intervals with lithological data, temperature-depth profiling is shown to have the capacity to detect aquitards, provided that the approximate depth of the aquitard is known, as well as the flux direction and magnitude across the aquitard. In combination with observed hydraulic gradients, the spatial variability of hydraulic conductivity of the aquitard could be evaluated. These values range from 10 to 100 mm/d, where earlier estimated values using more traditional methods suggested a range of  5 to 10 mm/d.

How to cite: Bense, V., Nie, L., and Oosterwijk, J.: Thermal profiling to quantify the spatial variability of ambient groundwater flow at a provisional groundwater abstraction site, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13937, https://doi.org/10.5194/egusphere-egu23-13937, 2023.

A.161
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EGU23-15371
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ECS
Bilal Tariq, Helen Kristine French, Stéphane Polteau, Helgard Anschütz, and Sean Salazar

A landfill constructed in fractured bedrock can pose a potential risk of contaminant leachate to the surroundings through fractures and/or fracture networks. Therefore, adequate understanding of factures and fracture networks is a key element for constructing environmentally safe, sustainable and long-term landfills in fractured bedrocks. Mapping of geological features especially fracture networks provides essential data to establish a fundamental understanding of the local geology and hydrogeology of such landfill sites.

The objective of this study to develop  a 3D model of fractures and fracture networks, surrounding a quarry in southwestern Norway, Rekefjord. The test site, selected as a potential landfill site, consists of  moderately fractured crystalline monzonorite near the shoreline. Eight previously drilled and logged observation boreholes (NGI) on the crest surrounding the open pit were analysed. Results of subsurface fracture mapping from well logs show that orientations of natural fractures are scattered and mostly appear to be open. The Terzaghi correction shows there could be more steeply dipping fractures, these are not well captured through vertical borehole logging. Additional field work consisted of drone scanning of the interior of the whole quarry and specific locations to generate a virtual 3D model. This 3D model is used to conduct fracture measurements using the LIME software. The fracture data extracted from the 3D model will be used to assess the correlation and consistency in fracture orientation between the internal rock face and borehole measurements. The geometry of fracture networks and individual fractures can have significant impact on flow through fractured rock. 

Results will also be used to constrain a numerical groundwater flow model to improve understanding of potential pathways of contaminants from the landfill to the surroundings. The results of this research will improve assessment methodology and criteria for new landfill sites in fractured bedrock.

How to cite: Tariq, B., French, H. K., Polteau, S., Anschütz, H., and Salazar, S.: Connecting the dots: Fracture mapping for landfill sites in fractured bedrock”, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15371, https://doi.org/10.5194/egusphere-egu23-15371, 2023.

A.162
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EGU23-16609
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ECS
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Ali Saeibehrouzi, Petr Denissenko, Soroush Abolfathi, and Ran Holtzman

The transport of solute particles is common in many natural and engineering processes, such as nutrition/contamination transport in subsurface systems or underground carbon dioxide sequestration.  While most of the available investigations concentrate on single-phase scenarios, more often, multiple fluids coexist, denoted frequently as unsaturated conditions. Here, and by means of direct numerical simulation, the effect of spatially correlated disorder in pore size is examined for two-phase displacement in viscous fingering regime. Following the stabilisation of fluids interface (steady-state condition), the solute solution is introduced into the invading phase with lower viscosity. Simulation results indicate that the spatial disorder impacts solute migration through the invading phase saturation and tortuosity of velocity streamlines. A bimodal variation can be seen from the histogram of probability of pore-scale Peclet number with zones being mostly dominated by either advection or diffusion. In addition, there exists a transition region with an interplay between both advective and diffusive mechanisms. The creation of trapped regions focuses the flow into preferential pathways, resulting in a higher dispersion coefficient. This, on the other side, forms a concentration gradient transverse to the direction of flow, directing solute solution through diffusivity from preferential pathways to low-velocity zones.

How to cite: Saeibehrouzi, A., Denissenko, P., Abolfathi, S., and Holtzman, R.: Effect of spatially correlated disorder on solute dispersion and mixing in partially saturated porous media, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16609, https://doi.org/10.5194/egusphere-egu23-16609, 2023.

A.163
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EGU23-17488
Arwa Rashed, Maria Klepikova, Gauthier Rousseau, Francesco Gomez, Joris Heyman, Benoît Fond, and Yves Méheust

The study of heat transport in porous media has recently attracted a lot of attention due to the wide range of industrial and geological applications, yet the impact of the structural heterogeneity of naturally occurring aquifers on their hydraulic and thermal properties is often disregarded. In that regard, a novel application of phosphor thermometry to porous media is proposed with the aim of examining under which conditions the validity of existing thermal transfer models in complex natural saturated porous media can be questioned. This experimental technique relies on monitoring the temperature-dependent luminescence properties of solid phosphor particles seeded into the fluid as tracers, using light sources and cameras. It offers the possibility of characterizing quantitatively the interaction between flow and heat transport processes at the pore scale in transparent analog porous media, with minimal interference and from spatially-resolved measurements, hereby overcoming the technical limitations of current experimental techniques, which are constrained to point temperature measurements.

Here, as proof of concept, we present a demonstration experiment performed on a slow-moving flow in a synthetic porous medium with a heterogenous size distribution, and using YAG:Cr3+, a thermographic phosphor with a temperature sensitivity exceeding 0.3%/K [1]. The measurements are performed using a modulated light source and are recorded at a sampling rate of 1 kHz during continuous injection of an aqueous solution which is initially at a constant temperature, different from that of the resident solution. The results show the dynamics of the spatial temperature distribution in the porous medium with a precision of ±0.3°C.

[1] J. L. Bonilla and B. Fond, "Phosphor thermometry using the phase-shift method: optimization and comparison with decay time method," 2022.

How to cite: Rashed, A., Klepikova, M., Rousseau, G., Gomez, F., Heyman, J., Fond, B., and Méheust, Y.: Optical thermometry to characterize heat transport in permeable porous media, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17488, https://doi.org/10.5194/egusphere-egu23-17488, 2023.

A.164
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EGU23-6531
Olivier Bour, Nataline Simon, Nicolas Lavenant, Gilles Porel, Benoît Nauleau, and Maria Klepikova

The monitoring of temporal variabilities of groundwater flows is a critical point in many hydrogeological contexts, especially for the characterization of coastal aquifers, sub-surface heterogeneities or else groundwater/stream interactions. Considering the lack of available methods, we investigate the possibility of monitoring and quantifying groundwater fluxes variations over time through active-Distributed Temperature Sensing (DTS) measurements. Active-DTS, consisting in heating a fiber optic cable, performs very well for investigating the spatial distribution of groundwater fluxes but the method has never been tested to continuously monitor groundwater fluxes changes. In this context, both numerical simulations and sandbox experiments were performed in order to assess the sensitivity of temperature elevation to variable flow conditions. Results first demonstrate that when a flow change is followed by a long-enough steady-state flow stage the temperature elevation stabilizes independently of previous fluxes conditions. Thus, the stabilization temperature can easily be interpreted to estimate groundwater fluxes using the analytical model commonly used under steady flow conditions to interpret active-DTS measurements. Under certain flow conditions, depending on the nature of flow variations, the approach also allows the continuous monitoring of fluxes variations over time. If instantaneous flow changes occur, the superposition principle can even be used to reproduce the temperature signal over time. In summary, we demonstrated through these preliminary results the possibility of for monitoring and/or quantifying the temporal dynamic of groundwater fluxes at different temporal scales including diurnal and periodic fluxes variations, which open very interesting perspectives for the quantification of subsurface processes.

How to cite: Bour, O., Simon, N., Lavenant, N., Porel, G., Nauleau, B., and Klepikova, M.: About the possibility of monitoring groundwater fluxes variations through active-DTS measurements, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6531, https://doi.org/10.5194/egusphere-egu23-6531, 2023.

A.165
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EGU23-11028
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ECS
Oshri Borgman, Francesco Gomez, Tanguy Le Borgne, and Yves Méheust

Solute transport in unsaturated porous media plays a crucial role in soil nutrient dynamics, pesticide leaching, and contaminant migration to aquifers through the vadose zone. Natural porous media are characterized by a strong structural heterogeneity, which impacts solute spreading and mixing and the resulting chemical reaction rates. In addition, incomplete pore-scale solute mixing requires high-resolution experimental measurements to understand the system’s mixing dynamics. Our goals are to 1) study the impact of structural heterogeneity on the spatial distribution of fluid phases and 2) establish how fluid phase arrangement impacts solute spreading and mixing during unsaturated flow. We use two-dimensional porous media consisting of circular posts in a Hele-Shaw-type flow cell. The positioning of the posts is random, but we control the medium’s heterogeneity by varying the disorder in the posts’ diameters and their spatial distribution’s correlation length; increasing this length introduces more structure in the porous medium.

In our experiments, we first establish an unsaturated flow pattern with a connected liquid phase and then introduce a fluorescent solute pulse transported by the moving liquid phase. We track the solute concentration and gradients’ evolution by taking periodic images of the flow cell and analyzing the fluorescence intensity field. Our results suggest that, as previously shown, decreasing the saturation degree enhances and sustains mixing rates in a disordered porous media due to the emergence of several preferential flow pathways during unsaturated flow. Moreover, increasing the solid posts’ spatial correlation reduces the number of air clusters and their interface roughness, and increases their mean size. This leads to fewer preferential flow paths during unsaturated flow for the higher correlated, more structured, porous media, compared to the less structured ones. This reduction in preferential flow paths’ number suppresses mixing rate enhancement in the more structured porous media, compared with the less structured porous media, during unsaturated flow. Our experiments show the non-trivial effect of structural heterogeneity and saturation degree on solute mixing in porous media flows. The effects demonstrated by these results are likely to affect reactive solute transport processes such as dissolution and precipitation and adsorption-controlled solute migration.

How to cite: Borgman, O., Gomez, F., Le Borgne, T., and Méheust, Y.: Impact of structural heterogeneity on solute transport and mixing in unsaturated porous media: An experimental study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11028, https://doi.org/10.5194/egusphere-egu23-11028, 2023.

A.166
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EGU23-16896
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ECS
Maliha Ashraf, Sumedha Chakma, and Ziauddin Ahammad

The Pharmaceuticals and Personal Care Products, PPCPs, a category of Emerging Contaminants are omnipresent in the environment. These PPCPs have allured significant importance globally over two decades. Because of the lack of efficient treatment systems concerning to their varying Spatio-temporal effects, they impose chronic toxicity on the environment. Therefore, understanding the fate and transport behavior of PPCPs is of prime importance for the successful accomplishment of remediation operations.  In the study, three different PPCPs viz. Metformin, Triclosan and Erythromycin were modeled using numerical techniques in the silty saturated porous media using the software- COMSOL Multiphysics. A fate and transport model considering advection, dispersion, degradation, and adsorption is conceptualized as imitating the real soil column scenario. The column was fed with continuous injection of the contaminants in consideration. Further, sensitivity analysis is carried out by varying flow and transport parameters (longitudinal dispersivity, Darcy’s velocity, adsorption coefficient (Kd), and degradation coefficient) by three orders of magnitude. The degradation and adsorption delayed the process of transport of the three ECs, thereby taking more time to travel through the column. Erythromycin having comparatively less Kd is detected in the column outlet before metformin and triclosan. The results depicted a denoting effect of adsorption, Darcy’s velocity, and degradation co-efficient, thereby highlighting the importance of adsorption, advection and degradation being important factors in the transportation of PPCPs via saturated silty soil. Moreover, the longitudinal dispersivity tends to have a negligible effect on the concentration modeled, thus proving to be a less significant parameter influencing the transport of PPCPs in the environment. The results of the simulation may serve as a foreboding tool for prior identification of the ever-increasing ECs in the environment. Furthermore, the results may prove to be useful in policymaking and risk assessment due to the PPCPs. 

How to cite: Ashraf, M., Chakma, S., and Ahammad, Z.: Apprehending the complex transport and fate behavior of Pharmaceuticals and Personal Care Products in Silty Saturated Porous media - A Numerical Study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16896, https://doi.org/10.5194/egusphere-egu23-16896, 2023.

A.167
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EGU23-6663
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ECS
Laura Burrel, Rowan Vernon, Jon Ford, Richard Haslam, Tom Randles, Helen Burke, Mark Woods, Jonathan Lee, and Katie Whitbread

The Yorkshire Wolds Chalk aquifer, provides the main source of water supply in East Yorkshire and the city of Hull, which have a population over 900.000. Its structural configuration, including the effects of faulting, influence groundwater flow across the region. However, stratigraphic and structural characterisation is challenging due to limited bedrock being exposed at surface, with most of its extension covered by Quaternary glacial deposits and arable fields and pastures. While the coastal sections have been well characterised through the years, inland areas of the Yorkshire Wolds Chalk aquifer have not been systematically mapped since the late 19th century. The available maps do not reflect present-day stratigraphic divisions or current tectonic understanding, leading to an underestimation of the structural complexity of the aquifer.

A multi-faceted approach to geological mapping is being undertaken in the region by the British Geological Survey, in collaboration with the Environment Agency and Yorkshire Water, integrating remote sensing, targeted field mapping, palaeontological analysis, 2D onshore seismic interpretation and borehole records. The objective of the project is to deliver an up-to-date geological map and structural model of the Chalk bedrock and Quaternary deposits which will impact on the groundwater resources management.

The recent mapping campaigns have led to identifying and characterising numerous new faults in different structural trends, which were not present on previous maps. It has also led to a significant shifting of stratigraphic contacts and formation thicknesses, which have more lateral variability than previously thought. We present some of the most recent updates on the Yorkshire Wolds Chalk aquifer map, which highlight the importance of revising old cartography using modern tectonic and stratigraphic concepts and a multidisciplinary approach to field data collection and compilation. We are also interested in discussing with the hydrogeologist community how to better capture and represent structural complexity around fault zones, so it has an impact on hydrogeological modelling.

How to cite: Burrel, L., Vernon, R., Ford, J., Haslam, R., Randles, T., Burke, H., Woods, M., Lee, J., and Whitbread, K.: 3D characterisation of the Yorkshire Wolds chalk aquifer, UK, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6663, https://doi.org/10.5194/egusphere-egu23-6663, 2023.