Morwick G360 Groundwater Research Institute

Author: G360group

Free Paper Available: Monitoring the evolution and migration of a methane gas plume in an unconfined sandy aquifer using time-lapse GPR and ERT

Posted by on in Press Release, Publications

We are pleased to announce the publication of a new open access journal article in the Journal of Contaminant Hydrology by G360 researchers in collaboration with researchers from the Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia.

https://doi.org/10.1016/j.jconhyd.2017.08.011

Abstract:
Fugitive methane (CH4) leakage associated with conventional and unconventional petroleum development (e.g., shale gas) may pose significant risks to shallow groundwater. While the potential threat of stray (CH4) gas in aquifers has been acknowledged, few studies have examined the nature of its migration and fate in a shallow groundwater flow system. This study examines the geophysical responses observed from surface during a 72 day field-scale simulated CH4 leak in an unconfined sandy aquifer at Canadian Forces Base Borden, Canada, to better understand the transient behaviour of fugitive CH4 gas in the subsurface. Time-lapse ground-penetrating radar (GPR) and electrical resistivity tomography (ERT) were used to monitor the distribution and migration of the gas-phase and assess any impacts to groundwater hydrochemistry. Geophysical measurements captured the transient formation of a CH4 gas plume emanating from the injector, which was accompanied by an increase in total dissolved gas pressure (PTDG). Subsequent reductions in PTDG were accompanied by reduced bulk resistivity around the injector along with an increase in the GPR reflectivity along horizontal bedding reflectors farther downgradient. Repeat temporal GPR reflection profiling identified three events with major peaks in reflectivity, interpreted to represent episodic lateral CH4 gas release events into the aquifer. Here, a gradual increase in PTDG near the injector caused a sudden lateral breakthrough of gas in the direction of groundwater flow, causing free-phase CH4 to migrate much farther than anticipated based on groundwater advection. CH4 accumulated along subtle permeability boundaries demarcated by grain-scale bedding within the aquifer characteristic of numerous Borden-aquifer multi-phase flow experiments. Diminishing reflectivity over a period of days to weeks suggests buoyancy-driven migration to the vadose zone and/or CH4 dissolution into groundwater. Lateral and vertical CH4 migration was primarily governed by subtle, yet measurable heterogeneity and anisotropy in the aquifer.

This research was made possible through an NSERC Strategic Partnerships Grant Project (SPG-P) awarded to Drs. John Cherry and Beth Parker (principal investigators), and collaborators Drs. Bernhard Mayer, Ulrich Mayer and Cathryn Ryan. Dr. Aaron Cahill provided a major role with proposal writing, experimental design and overall project management, both with field implementation and project reporting, and is now a research associate at the University of British Columbia Department of Earth, Oceanic and Atmospheric Sciences. An NSERC Banting Fellowship provided support to Dr. Colby Steelman.

Dr. Beth Parker Awarded Nova Domus Grant

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Nova Domus is an Erasmus Mundus Key Action 2 project which aims to facilitate research and education links across a consortium of universities in Europe and North America in the fields of:

  • medical sciences
  • public health
  • natural sciences
  • physics and engineering

Nova Domus grants enable doctoral, post-doctoral, and staff candidates to undertake a period of research/ work/ training in a partner universities in Europe to the benefit of both the individual, and their wider research area.

lund_logoDr. Beth Parker recently completed a Nova Domus sponsored research exchange at Lund University from March 18-April 22, 2017.  During this research exchange, Beth was an invited speaker on topics that included:

  • Geologic time scales vs. contaminant transport time scales
  • High resolution characterization needed for groundwater flow system and transport predictions: How much data is enough?
  • The importance of hydrologic unit delineation sedimentary rock aquifers

Beth stated “This Nova Domus program offered an amazing opportunity to connect with new colleagues and a new place that may have never otherwise occurred. I am grateful for this memorable experience and looking forward to continuing the scientific collaborations with Dr. Sparrenbom and her colleagues for many years“.

G³⁶⁰ Voted One of the Best Conference Papers at SAGEEP in 2017

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Colby SteelmanIn March of this year, G360 attended the Symposium on the Application of Geophysics to 
Engineering and Environmental Problems (SAGEEP) in Denver, Colorado.  

We are pleased to announce that G360 researcher Colby Steelman‘s paper titled “Hydrogeophysical Investigations in Fractured Bedrock Rivers: Understanding Groundwater-Surface Water Interactions, Subsurface Flow and Transport” was voted, by the SAGEEP evaluation ballots, as one of the best papers delivered at the 2017 conference.  

Interested to hear more?  This research was also recently published in Hydrology and Earth System Science journal.

G360 Student Awarded the Prestigious Arrell Scholarship

Posted by on in Awards

Kathleen-Johnson-212x300

Kathleen Johnson, a new student under the supervision of Dr. Beth Parker, was recently awarded one of five Arrell Scholarships from the University of Guelph.

The Arrell Food Institute at the University of Guelph provides scholarships for emerging graduate-level scholars who are not only academically outstanding
but also passionately committed to ensuring that future generations are well fed, that diets are
nutritious and equitable, and that agriculture is sustainable.

Scholarship criteria are based on:

  • Outstanding academic achievement;
  • Relevance of proposed research and personal motivation to the vision of the Arrell Food Institute;
  • Demonstration of commitment to public engagement, as evidenced in the CV; and an
  • Interview with the scholarship selection committee for those applicants that are shortlisted.

Originally from Embro, Ont., an hour’s drive southwest of Guelph, Kathleen Johnson had these thoughts about her research and it’s relevance to the Arrell Scholarship requirements:

“My research will focus on understanding the flow and fate of agricultural and industrial contaminants in the fractured bedrock aquifer beneath the city of Guelph,” she says.

“This research will improve our understanding of the source and fate of the contaminants in these aquifers. Second, this knowledge will allow us to better prepare and ultimately manage agricultural operations to limit or mitigate contaminant occurrence, which will lead to improved water quality for growing food in a safe and sustainable manner in the future.”

Kathleen believes food production will be sustainable only within the limits of local and global water systems.

“Food research is not just about being able to produce enough food for our population but also ensuring everyone has access to affordable, high-quality food,” Johnson says.

“Going forward, we need to shape our food systems to reduce inequalities and be more sustainable. More research is needed before this can become a reality.”

Read about other 2017 Arrell Scholars at the University of Guelph website