Adventures in Groundwater Monitoring: Approaches for Shale Gas Development Sites

Assessing the potential risks of shale gas drilling and hydraulic fracturing on local and regional groundwater resources has been challenging in the absence of substantial amounts of field data. Obtaining baseline data at drill sites for up to a year before pad construction, performing continuous monitoring of multiple aquifer zones during the drilling and hydraulic fracturing process, and continuing periodic monitoring for several years after well completion are all needed to fully understand the possible pathways for contaminants to reach shallow aquifers. Attempts to engage drillers and landowners to allow monitoring adjacent to drill sites have met with resistance on several levels. Our experience has been that landowners are often concerned the monitoring process will delay gas well completion and production, thereby impacting their royalty payments. Drillers are concerned that by allowing monitoring at one site, it may be required at all sites. Another concern expressed is that if the gas well drilling is done correctly, groundwater monitoring will produce non-detects and we will learn nothing. A third argument is that drillers are already collecting water samples from nearby domestic supply wells, and another study is not necessary. Our responses to these concerns have been: (1) monitoring will be a scientific, not a regulatory activity, and will not impact drilling schedules or royalty payments; (2) even non-detects are helpful for reducing uncertainty in engineering risk assessment models; and (3) domestic wells are commonly open-hole completions that mix water from multiple aquifer flow zones, making it impossible to pin down the origin of stray gas or groundwater contaminants. Scientific access to planned future drill sites has been obtained recently in Pennsylvania and South Dakota. Multi-year field monitoring programs are under development to collect data at both locations, in collaboration with state and university partners. The status of these plans will be presented.