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/

Navigating California’s Waste Discharge Requirements for Wineries

California wineries are facing common compliance challenges under the Statewide General WDR, from monitoring requirements and water softener brine separation to pond...

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California wineries are facing common compliance challenges under the Statewide General WDR, from monitoring requirements and water softener brine separation to pond standards and compliance schedules.

In the new North Bay Business Journal article, “Navigating California’s Waste Discharge Requirements for Wineries,” Mehran Ebrahimi, PE, and co-author Donald Sobelman of Farella Braun + Martel take a closer look at these challenges and share practical considerations for wineries working toward compliance.

Read the article: https://www.pressdemocrat.com/2026/09/11/navigating-californias-waste-discharge-requirements-for-wineries/

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

expertise in Environmental Assessment, Water Resources, Geochemistry, NEPA, CERCLA, Renewables, and Permitting for the Mining, Agriculture, Industrial, and Energy sectors in Montana

GSI Expands into Montana

GSI is thrilled to share the news of our expansion into the Big Sky Country of Montana with the addition of Joel Jacobson,...

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GSI is thrilled to share the news of our expansion into the Big Sky Country of Montana with the addition of Joel Jacobson, MSc, MBA, Marie-Hélène Paré, Laura Pfister, Dave Rugh, LG, LHG, Amelia Tallman, and Dr. David Tooke.

This group brings significant expertise in Environmental Assessment, Water Resources, Geochemistry, NEPA, CERCLA, Renewables, and Permitting for the Mining, Agriculture, Industrial, and Energy sectors.

GSI provides high quality technical and regulatory expertise to industry and government to address a broad range of environmental issues. We specialize in solving complex environmental problems by leveraging our extensive knowledge of environmental regulations, stressing accurate data collection and analysis, and applying new technologies to our clients’ most difficult challenges.

We look forward to great things ahead as part of the GSI team!

Chuck Newell, Vice President/Principal Engineer, has been singularly honored with the prestigious 2024 Gordon Maskew Fair Award from the American Academy of Environmental Engineers and Scientists (AAEES)

Gordon Maskew Fair Award

Exciting News! The American Academy of Environmental Engineers and Scientists (AAEES) singularly honors Chuck Newell, Vice President/Principal Engineer with the prestigious 2024...

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Exciting News! The American Academy of Environmental Engineers and Scientists (AAEES) singularly honors Chuck Newell, Vice President/Principal Engineer with the prestigious 2024 Gordon Maskew Fair Award!

The award recognizes Dr. Newell’s extensive work in environmental science, including numerous publications, patents, and contributions to the field as exemplary of the goal to “protect and enhance environmental quality.” Congratulations on this well-deserved recognition!

The Gordon Maskew Fair Award honors one of the pioneers of environmental engineering, Dean Fair. In addition to his exemplary career, his living legacy includes hundreds of prominent practicing engineers and eminent professors who continue to emulate his values. He taught his students not only the technical aspects of the field but also inspired them to use their skills to protect and enhance environmental quality.

Through the Fair Award, the Academy seeks to identify Board Certified Environmental Engineers, Members, or Scientists who have contributed to the status of the environmental engineering or science professions by:

  • Exemplary professional conduct
  • Recognized achievements in the practice of environmental engineering and science
  • Significant contributions to the control of the quality of the world’s environment

Dr. Charles Newell holds the position of Vice President at GSI Environmental Inc. and is based in Houston, Texas. He is recognized as a Board Certified Environmental Engineer (BCEE) by the American Academy of Environmental Engineers and Scientists, a Certified Ground Water Professional by the National Ground Water Association (NGWA) and serves as an Adjunct Professor in the Department of Civil and Environmental Engineering at Rice University. His academic and professional contributions are extensive, including co-authorship of four U.S. EPA publications, 12 environmental software systems, over 70 journal articles, five patents, and two books, notably “Natural Attenuation of Fuels and Chlorinated Solvents”.

Dr. Newell’s areas of expertise encompass site characterization, groundwater modeling, risk assessment, natural attenuation, LNAPL/DNAPL, remediation technologies, long-term monitoring strategies, technology transfer, and management of PFAS-impacted sites.  He has served as a Principal or Co-Principal Investigator in numerous environmental R&D projects sponsored by various agencies and organizations, including the U.S. Department of Energy, American Petroleum Institute, U.S. Environmental Protection Agency, U.S. Department of Defense, and diverse industrial clients.

Dr. Newell is the recipient of the Hanson Excellence of Presentation Award from AAPG, the Outstanding Presentation Award from AIChE, and the 2001 Wesley W. Horner Award from ASCE. Additionally, he received the 2008 Outstanding Alumni Award from Rice University, the 2014 Strategic Environmental Research and Development Program (SERDP) Project of the Year Award, the 2016 Interstate Technology & Regulatory Council (ITRC) Environmental Excellence Award, and the 2020 Foundation Achievement Award from the Association for Environmental Health and Science.

Contact Chuck directly at Charles J. Newell, PhD, PE, BCEE

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