Flow of Groundwater at the Interface with Permafrost

Paturi, Sairavichand

Flow of Groundwater at the Interface with Permafrost

Thursday, September 8, 2016: 2:15 p.m.

Sairavichand Paturi , Water and Environmental Research Center, Department of Civil and Environmental Engineering, University of Alaska Fairbanks, Fairbanks, AK

David Barnes, Ph.D., PE , Water and Environmental Research Center, Department of Civil and Environmental Engineering, University of Alaska Fairbanks, Fairbanks, AK

Currently, the largest contaminated groundwater plume in Alaska exists in a discontinuous permafrost aquifer in the area of North Pole, Alaska. The aquifer is contaminated with sulfolane; a compound used in the refining of petroleum. As a part of remediation a relatively large monitoring well network has been installed to track the dispersion of the contaminant. Monitoring results revealed that the plume is much more dispersed in the lateral direction representing the contaminant presence in suprapermafrost and subpermafrost portions of the aquifer. Previous studies of this aquifer has shown that thawed through taliks exists in different areas of the plume providing connectivity between the sub and suprapermafrost portions of the aquifer. These taliks are providing the pathways for sulfolane to reach the subpermafrost portion of the aquifer and possibly retract into the suprapermafrost portion of the aquifer.

The objective of this study is to determine the pathway for sulfolane to reach the subpermafrost portion of the aquifer, we accomplished this goal by determining the vertical and horizontal flow gradients in key locations of the plume. Given the errors in water level measurements due to the frost heave and thaw settlement of monitoring wells indicates large measurement errors. Monte Carlo method is used to determine the asymmetrical errors. By reducing the measurement errors a three dimensional model with flow vector visualization of groundwater with discontinues permafrost has been created. The effect of seasonal variability in the flow pattern unleashed new understandings of the contamination plume boundary. With a precise flow vector visualization, seasonal variability and measured concentrations of sulfolane, a cutting-edge groundwater flow pattern in discontinuous permafrost regions has been determined. This is the fundamental study that has investigated groundwater flow at the interface with permafrost bodies in areas of discontinuous permafrost. Understanding this interaction is key to our understanding of contaminant transport, aquifer recharge, and resource development in subarctic environments.

Sairavichand Paturi, Water and Environmental Research Center, Department of Civil and Environmental Engineering, University of Alaska Fairbanks, Fairbanks, AK

Sairavichand Paturi is a Masters student in Environmental Engineering at UNIVERSITY OF ALASKA FAIRBANKS. Research concentration is Groundwater dynamics and presently working on groundwater flow pattern in permafrost zones like Alaska.

David Barnes, Ph.D., PE, Water and Environmental Research Center, Department of Civil and Environmental Engineering, University of Alaska Fairbanks, Fairbanks, AK

David Barnes is a Professor of Environmental Engineering in the Department of Civil and Environmental Engineering and the Water and Environmental Research Center at the University of Alaska Fairbanks. He teaches and performs research in the area of environmental engineering specifically as the topic pertains to contaminated soil and groundwater. Over the last 14 years Barnes has focused his research on protection of human health and environmental quality in cold regions.