Explicit Modeling of Radon‐222 in HydroGeoSphere During Steady State and Dynamic Transient Storage

Gilfedder, Benjamin; Cartwright, Ian; Hofmann, Harald; Frei, Sven

doi:10.1111/gwat.12847

Cited by 29 publications

(43 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…CC BY 4.0 License. Again, we would like to point out that our results can be considered valid for systems that do not experience a large fraction of preferential flow in the soil and bedrock since we only model flow taking place in the porous matrix of the subsurface not found in previous studies (Hrachowitz et al, 2009;Godsey et al, 2010;Berghuijs and Kirchner, 2017;Birkel et al, 2016). Therefore, in terms of expanding the modeling effort, it would be very beneficial to include both evapotranspiration and macropore flow into the simulations.…”

Section: Connection Between the Shape Of Ttds And The Flow Path Number Fmentioning

confidence: 90%

“…The surface and subsurface domains are numerically coupled using a dual node approach, allowing for the interaction of water and solutes between the surface and subsurface. The general functionality of HGS and its adequacy for solving analytical benchmark tests has been proven in several model intercomparison studies (Maxwell et al, 2014;Kollet et al, 2017) and its solute transport routines have been verified against laboratory (Chapman et al, 2012) and field measurements (Sudicky et al, 2010;Liggett et al, 2015;Gilfedder et al, 2019). Since our modeling approach entails only subsurface flow in porous media (no explicit fractures or macropores are included), the resulting TTDs have to be considered a special subset of distributions lacking some of the dynamics we can expect in real-world catchments while still providing a sound basis for further investigations (like, e.g., adding more complex interaction dynamics along the flow pathways).…”

Section: Methodsmentioning

confidence: 97%

“…A number of studies reported on the best-fit shape of Gamma distributions generally ranging from α 0.01 to 0.90 (Hrachowitz et al, 2009;Godsey et al, 2010;Berghuijs and Kirchner, 2017;Birkel et al, 2016) which indicates L-shaped distributions with high initial values and heavier tails. Several studies found that α values decrease with increasing wetness conditions (e.g., Birkel et al, 2012;Tetzlaff et al, 2014) causing higher initial values and heavier tails.…”

Section: Controls On Shape Variationsmentioning

confidence: 99%

See 2 more Smart Citations

On the shape of forward transit time distributions in low-order catchments

Heidbüchel¹,

Yang²,

Мусолфф³

et al. 2019

Preprint

View full text Add to dashboard Cite

Abstract. Transit time distributions (TTDs) integrate information on timing, amount, storage, mixing and flow paths of water and thus characterize hydrologic and hydrochemical catchment response unlike any other descriptor. Here, we simulate the shape of TTDs in an idealized low-order catchment investigating whether it changes systematically with certain catchment and climate properties. To this end, we used a physically-based, spatially-explicit 3-D model, injected tracer with a precipitation event and recorded the resulting TTDs at the outlet of a small (~ 6000 m2) catchment for different scenarios. We found that the TTDs can be subdivided into four parts: 1) early part – controlled by soil hydraulic conductivity and antecedent soil moisture content, 2) middle part – transition zone with no clear pattern or control, 3) later part – influenced by soil hydraulic conductivity and subsequent precipitation amount and 4) very late tail of the breakthrough curve – governed by bedrock hydraulic conductivity. The modeled TTD shapes can be predicted using a dimensionless number: higher initial peaks are observed if the inflow of water to a catchment is not equal to its capacity to discharge water via subsurface flow paths, lower initial peaks are connected to increasing available storage. In most cases the modeled TTDs were humped with non-zero initial values and varying weights of the tails. Therefore, none of the best-fit theoretical probability functions could exactly describe the entire TTD shape. Still, we found that generally the Gamma and the Advection-Dispersion distribution work better for scenarios of low and high hydraulic conductivity, respectively.

show abstract

Section: Connection Between the Shape Of Ttds And The Flow Path Number Fmentioning

confidence: 90%

Section: Methodsmentioning

confidence: 97%

Section: Controls On Shape Variationsmentioning

confidence: 99%

See 1 more Smart Citation

On the shape of forward transit time distributions in low-order catchments

Heidbüchel¹,

Yang²,

Мусолфф³

et al. 2019

Preprint

View full text Add to dashboard Cite

show abstract

“…There are software packages that have been applied elsewhere such as HydroGeoSphere (e.g. Gilfedder et al, 2019;Goderniaux et al, 2009;Tang et al, 2017) and MIKE-SHE (e.g. Butts et al, 2019;House et al, 2016;Bandini et al, 2017) that appear promising to try in addition to MODFLOW, which has been traditionally used in braided river modelling of the groundwater-surface water interface.…”

Section: Hydrochemistrymentioning

confidence: 99%

A review of methods for measuring groundwater–surface water exchange in braided rivers

Coluccio

Morgan

2019

Hydrol. Earth Syst. Sci.

View full text Add to dashboard Cite

Abstract. Braided rivers, while uncommon internationally, are significant in terms of their unique ecosystems and as vital freshwater resources at locations where they occur. With an increasing awareness of the connected nature of surface water and groundwater, there have been many studies examining groundwater–surface water exchange in various types of waterbodies, but significantly less research has been conducted in braided rivers. Thus, there is currently limited understanding of how characteristics unique to braided rivers, such as channel shifting, expanding and narrowing margins, and a high degree of heterogeneity affect groundwater–surface water flow paths. This article provides an overview of characteristics specific to braided rivers, including a map showing the regions where braided rivers are mainly found at the global scale: Alaska, Canada, the Japanese and European Alps, the Himalayas, Russia, and New Zealand. To the authors' knowledge, this is the first map of its kind. This is followed by a review of prior studies that have investigated groundwater–surface water interactions in braided rivers and their associated aquifers. The various methods used to characterise these processes are discussed with emphasis on their effectiveness in achieving the studies' objectives and their applicability in braided rivers. We also discuss additional methods that appear promising to apply in braided river settings. The aim is to provide guidance on methodologies most suitable for future work in braided rivers. In many cases, previous studies found a multi-method approach useful to produce more robust results and compare data collected at various scales. Given the challenges of working directly in braided rivers, there is considerable scope for the increased use of remote sensing techniques. There is also opportunity for new approaches to modelling braided rivers using integrated techniques that incorporate the complex river bed terrain and geomorphology of braided rivers explicitly. We also identify a critical need to improve the conceptual understanding of hyporheic exchange in braided rivers, rates of recharge to and from braided rivers, and historical patterns of dry and low-flow periods in these rivers.

show abstract

“…Gas exchange rate coefficients are further needed in surface‐water ecology, since gas exchanges sustain stream metabolism by providing oxygen to the streams through reaeration (Aristegi et al 2009; Knapp et al 2015). They are also crucial for the many hydrogeochemical studies that use natural gas tracers such as radon, CFC, helium, or oxygen (Cook et al 2003; Cartwright et al 2014; Avery et al 2018; Gleeson et al 2018; Gilfedder et al 2019).…”

mentioning

confidence: 99%

A new method to quantify air–water gas exchanges in streams based on slug injection and semicontinuous measurement

Vautier

Abhervé

Chatton

et al. 2020

Limnology & Ocean Methods

View full text Add to dashboard Cite

Gas exchanges between streams and atmosphere strongly impact biogeochemical cycles, yet their quantification in space and time remains challenging. We propose a new method to measure gas exchange rate coefficients in headwater streams. The method is based on simultaneous slug injections of a conservative tracer and a volatile tracer, coupled to in situ semicontinuous measurements. Its originality lies in the mathematical exploitation of the tracers' breakthrough curves. Taking advantage of the entire breakthrough curves, we infer the gas exchange rate coefficient from a comparative analysis of the shape of the volatile and the conservative breakthrough curves. Tests on synthetic datasets confirmed the validity of the mathematical framework for the whole range of gas exchange rate coefficients found in headwater streams. Field experiments further attested to the real-world applicability of the method. Salt and helium injections were performed in a first-order stream and the helium breakthrough curves were obtained using in situ membrane inlet mass spectrometry. This new method allows to determine the gas exchange rates directly in the field, without any external calibration of the data. Its fast implementation enables a wider spatial coverage of the measurements of gas exchange rates, and thus offers an opportunity to improve the large-scale estimates of CO 2 emissions from headwater streams. More generally, our study highlights the informative potential of semicontinuous datasets and encourages further investigation of possible use of temporal signals.

show abstract

Explicit Modeling of Radon‐222 in HydroGeoSphere During Steady State and Dynamic Transient Storage

Cited by 29 publications

References 62 publications

On the shape of forward transit time distributions in low-order catchments

On the shape of forward transit time distributions in low-order catchments

A review of methods for measuring groundwater–surface water exchange in braided rivers

A new method to quantify air–water gas exchanges in streams based on slug injection and semicontinuous measurement

Contact Info

Product

Resources

About