Around half of all US hydraulically fractured wells stimulated in 2014 exist within 2 to 3 kilometers of a domestic groundwater well, researchers report.
“Our results underscore the importance of increased water monitoring efforts…”
About 45 million Americans get their drinking water from private groundwater wells rather than a public utility. The Environmental Protection Agency regulations that protect public drinking water systems don’t apply to privately owned wells, leaving owners responsible for ensuring their water is safe from contaminants.
In assessing how frequently hydraulic fracturing takes place close to a public water supply, a 2016 EPA report says that drinking water supplies located near hydraulic fracturing sites are more likely to be affected should a contamination event occur. How many privately-owned groundwater wells could face a similar fate was undetermined, however. The new study sought to change that.
The investigators amassed a large database of private drinking water wells and compared their locations to hydraulic fracturing sites. Conducting a scientific analysis of data that spanned 15 years, from 2000 to 2014, and covered nearly 27,000 wells in 14 states.
“This co-location emphasizes the need to determine the frequency that hydraulic fracturing activities impact groundwater well water quality. This knowledge is important to maintaining high-quality water in many domestic wells,” says coauthor Scott Jasechko, an assistant professor at the Bren School of Environmental Science & Management at the University of California, Santa Barbara.
“Our results underscore the importance of increased water monitoring efforts near both hydraulically fractured and conventional oil and gas wells in ascertaining the risk of contamination and in protecting water well quality.”
Jasechko and coauthor Debra Perrone charted the data on a variety of maps, one of which tracked hotspots. “These hotspots are areas where, in light of potential contamination mechanisms, limited resources for assessing spill frequency and well integrity could be used more effectively and efficiently,” explains Perrone, an assistant professor in the environmental studies program.
Perrone notes that some hotspot areas include not only hydraulically fractured but also conventional oil and gas wells, which are more abundant. “We can use these hotspot analyses to focus resources, so that we can learn more about oil and gas contamination mechanisms: How often do they occur, and do they have an impact on groundwater?” she says.
“Our analysis underscores the need to increase monitoring efforts to maximize the probability that we can identify well waters that may be impacted, and do our best to remediate, contain, and isolate potentially contaminated waters before they cause harm,” Jasechko adds.
“We can consider stronger policies that include requirements for repeated groundwater quality testing of the many domestic self-supply wells that exist close to hydraulic fracturing.”
Often, limited available data can limit research. In this case, the problem is a lack of consistent data across states as well as across industries. In fact, the scientists found vast differences in how states collect groundwater data.
“One policy recommendation would be to have a national standard for data collection on groundwater well construction,” Perrone says. “On the energy side, a national standard for data collection for both unconventional and conventional oil and gas wells could provide opportunities for increased transparency across jurisdictional boundaries.”
Their results appear in the Proceedings of the National Academy of Sciences.
Source: UC Santa Barbara