Years participated in RESESS:
Academic Affiliation: Alfred University
Research Mentor: Laura Lautz
Communications Mentor: Daniel Nothaft
Crystal grew up in New York City, New York. Her passion in geoscience began on a class camping trip in the 7th grade, where learning how flint can be used to start a fire sparked her interest in rocks and their applications. Since then she has focused her interests on soil science and hydrology. She hopes to contribute to these fields by filling in gaps and challenging discrepancies in existing research. This summer, Crystal developed an interannual time series of naturally occurring methane concentrations in the advance of unconventional gas production in the southern tier of New York.
Temporal Pattern of Naturally Occurring Methane Levels in Domestic Water Wells, Overlying the Marcellus Shale in New York
Increasing unconventional gas extraction, particularly in the Marcellus Shale, has led to concern over the risk of groundwater contamination from faulty well casings. However, since there is little data on baseline methane levels and natural methane variability prior to drilling, it is difficult to differentiate natural groundwater methane from methane caused by unconventional drilling.
To develop a time series of methane concentrations prior to unconventional drilling in the Marcellus Shale formation, we sampled methane in 137 domestic drinking water wells in the southern tier of New York, where drilling is currently banned, and then resampled 28 of the wells with the highest methane concentrations in 2014 and 2016. Methane concentrations in 2013, 2014 and 2016 were all positively correlated with one another, with correlation coefficients > 0.8. In all three years, >10% of observed methane concentrations (in the subsample of 26) were above warning levels (>10 mg/L).
To improve predictions of natural methane occurrence in New York, as well as regions with similar hydrogeology overlying the Marcellus shale, we also analyzed correlations between methane concentrations and two major aquifer characteristics coincident with methane presence: Na-rich water chemistry, and/or valleys. Although confined aquifers are closely related to the presence of methane, we were not able to explore aquifer confinement as a characteristic due to limited stratigraphic records at the well locations. Understanding the natural conditions favorable to methane occurrence will help identify the differences between methane migrations due to unconventional drilling versus natural occurrence.