Aqueous and surface expression of subsurface GHGs: Subsurface mass transfer effects
Cole J C Van De Ven1, Kevin G Mumford1
1Queen's University, Department of Civil Engineering, Kingston, Ontario, K7L 3N6, Canada.
Water Research
|December 7, 2019
Summary
Subsurface greenhouse gas (GHG) releases impact air and water quality. Understanding gas flow and groundwater velocity is crucial for assessing risks and informing climate policy.
Area of Science:
- Environmental Science
- Geoscience
- Climate Science
Background:
- Greenhouse gas (GHG) releases from subsurface environments pose risks to atmospheric composition and water quality.
- Climate change necessitates accurate quantification of these emissions for risk management and policy development.
- Subsurface GHGs, such as methane and carbon dioxide, can manifest as surface atmospheric emissions or aqueous contamination in groundwater.
Purpose of the Study:
- To investigate the environmental expressions of flowing subsurface greenhouse gases.
- To determine the factors controlling the surface and aqueous expressions of subsurface GHG releases.
- To highlight the importance of subsurface mass transfer in risk assessment.
Main Methods:
- Utilized high-resolution observations from an analog experimental system.
- Employed analytical modeling to simulate GHG flow dynamics.
- Analyzed the relationship between gas flow rate and groundwater velocity.
Main Results:
- The surface and aqueous expressions of GHG releases are dependent on gas flow rate and groundwater velocity.
- In deeper systems, dissolution into groundwater can limit atmospheric emissions, leading to water quality degradation without obvious surface indicators.
- Subsurface mass transfer significantly influences the pathways and impacts of leaking GHGs.
Conclusions:
- Mass transfer processes within the subsurface are critical for accurately quantifying and monitoring risks associated with leaking GHGs.
- Failure to consider subsurface dissolution can lead to underestimation of risks to water resources.
- Effective mitigation strategies for subsurface GHG leaks require a comprehensive understanding of hydrogeological controls.
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