Implementation and Evaluation of Fully 3D Richards’ Equation in MODFLOW 6

Sebastián Vázquez-Gasty is the lead author of a new paper in Groundwater titled “Implementation and Evaluation of Fully 3D Richards’ Equation in MODFLOW 6,”...

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Sebastián Vázquez-Gasty is the lead author of a new paper in Groundwater titled “Implementation and Evaluation of Fully 3D Richards’ Equation in MODFLOW 6,” alongside GSI’s Sorab Panday, Christian Langevin of S.S. Papadopulos & Associates, and Tirthankar Roy of the University of Nebraska-Lincoln.

The paper introduces a fully three-dimensional Richards’ equation solver integrated into MODFLOW 6, enabling researchers and groundwater professionals to more accurately simulate water movement through saturated and unsaturated soils, including capillary effects and lateral moisture flow.

Using three benchmark tests against established groundwater modeling software, the researchers demonstrated strong agreement in simulated moisture and pressure responses, along with computational efficiency and numerical stability. This advancement offers new capabilities for studying groundwater recharge, vadose-zone processes, and complex subsurface flow conditions.

Congratulations to Sebastián and his co-authors on this publication and their contributions to advancing groundwater modeling capabilities!

Read the paper and access the research implementation and benchmark files here: https://www.gsienv.com/software/modflow-6-richards/modflow6-richards/

Using the Transition Assessment Teaching Assistant to Evaluate a Transition from Pump and Treat to MNA

We are pleased to share that Hiroko Hort, David Adamson, and Charles Newell recently co-authored “Using the Transition Assessment Teaching Assistant to...

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We are pleased to share that Hiroko Hort, David Adamson, and Charles Newell recently co-authored “Using the Transition Assessment Teaching Assistant to Evaluate a Transition from Pump and Treat to MNA.”

Co-authored with John T. Wilson, Barbara Wilson, Mark Ferrey, David L. Freedman, Anangelica Rivera Cruz, and Olivia Groshans, the article explores how the Transition Assessment Teaching Assistant can be used to evaluate whether a site may be ready to transition from pump and treat to monitored natural attenuation.

This paper demonstrates how practical, decision-focused analysis can help clients better understand remedial performance, plan for long-term site management, and determine next steps with greater confidence.

Read the full open-access article here: https://ngwa.onlinelibrary.wiley.com/doi/10.1111/gwmr.70046

Biotransformation Processes Relevant to Geologic Carbon Sequestration: Potential Implications for Environmental Fate

A new publication examines how microbial processes may influence the fate of CO2 in geologic carbon sequestration settings. The article, Biotransformation Processes...

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A new publication examines how microbial processes may influence the fate of CO2 in geologic carbon sequestration settings.

The article, Biotransformation Processes Relevant to Geologic Carbon Sequestration: Potential Implications for Environmental Fate, is published in Environmental Science & Technology and is authored by GSI experts Lisa J. Molofsky, Thomas E. McHugh, Danny Kingham, and Charles J. Newell, with contributions from Sven Lahme, Kelly M. McFarlin, Paul G. Koster van Groos, Frank E. Löffler, Louise Camenzuli, Leanne Walker, Sophie L. Nixon, and Trent A. Key.

The paper reviews how CO2-driven geochemical changes can alter microbial communities and trigger biotransformation processes that move carbon into mineral, gas, or organic phases. It also explores implications for both deep storage formations and nontarget environments such as shallow groundwater, the vadose zone, and marine systems, while identifying key knowledge gaps that affect long-term prediction of CO2 behavior.

Read the full open-access article here:
https://pubs.acs.org/doi/10.1021/acs.est.5c02389

Assessing future hydrologic extremes using an integrated hydrology and river operations model in the Russian River watershed

A new article by Ayman Alzraiee and Richard Niswonger has been published in Journal of Hydrology: Regional Studies. The article, “Assessing future...

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A new article by Ayman Alzraiee and Richard Niswonger has been published in Journal of Hydrology: Regional Studies.

The article, “Assessing future hydrologic extremes using an integrated hydrology and river operations model in the Russian River watershed,” presents an integrated surface water, groundwater, and operations modeling approach to evaluate how climate change and water use may affect streamflow conditions.

The study finds that groundwater pumping can significantly deplete streamflow, streamflow droughts become longer and more severe under climate change scenarios, peak flows increase substantially in wetter futures, and reservoirs play a key role in buffering these impacts across the watershed.

Read the full open-access article here:
https://www.sciencedirect.com/science/article/pii/S2214581825008456

Charles J. Newell and David T. Adamson: "A Long Way to Go: Challenges and Strategies for Managing PFAS in Groundwater" explores national-scale PFAS remediation strategies.

A Long Way to Go: Challenges and Strategies for Managing PFAS in Groundwater

A new publication in "Remediation" features contributions from GSI’s Charles J. Newell and David T. Adamson: "A Long Way to Go: Challenges...

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A new publication in “Remediation” features contributions from GSI’s Charles J. Newell and David T. Adamson: “A Long Way to Go: Challenges and Strategies for Managing PFAS in Groundwater.”

Co-authored with Paul B. Hatzinger (APTIM) and John S. Cook, this open access article explores national-scale PFAS remediation strategies by comparing pump-and-treat systems within situ permeable sorptive barriers across more than 10,000 hypothetical contaminated sites in the U.S.

The analysis finds that containment-focused approaches at a greater number of sites may offer more effective and cost-efficient risk reduction than intensive cleanups at fewer locations. The authors propose a phased national strategy: near-term containment and exposure prevention, followed by targeted mass removal as in situ destructive technologies evolve.

Read the open access article about challenges and strategies for managing PFAS in groundwater: https://onlinelibrary.wiley.com/doi/full/10.1002/rem.70028

This article was developed in support of a wider tech transfer-focused project led by Dr. Hatzinger and funded by PFAS-Related R&D Efforts, SERDP-ESTCP

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