The water demand associated with unconventional fossil fuel extraction and the management of the associated produced wastewater present significant environmental challenges. Water usage for unconventional fossil fuel extraction varies in different areas of the country, but overall is a small fraction of total water withdrawals for most locations. Produced water volumes and quality also vary nationwide, and disposal can have significant environmental impacts, especially if produced water is discharged to surface waters. This work discusses water use and requisition, changes in quantity and management of produced water nationwide from 2007 to 2017, and the environmental effects of management options. As unconventional natural gas production expands, selection of management options that do not lead to significant environmental impacts must be prioritized.

Historical data can be used to evaluate water impacts from unconventional oil and gas extraction. “Grey” literature measurements of water quality before, during, and after unconventional extraction activities offer a potentially powerful resource for the evaluation of water quality impacts, and these data have rapidly expanded with regulatory response to the unconventional boom. However, historical data are limited in the variety of measured constituents and require substantial effort to reconstruct, revisit, and re-evaluate. Ultimately, available data were limited as data from only a single county (Bradford) included constituents necessary to use the vast majority of these elemental ratio systems. Further, even when data were available, they were often measured with relatively poor sensitivity, precluding their use as early indicators of contamination. This case study accentuates the continued need to establish background conditions, particularly in regions that have accumulated historical impacts, and further, ensure these characterizations incorporate sensitive testing for known chemistries associated with emerging and novel processes.

In late 2008 increasingly high concentrations of total dissolved solids (TDS) exceeding Federal Safe Drinking Water Act (SDWA/PL 93-523) standards of 500 milligrams per liter (mg/L) for public water supplies were found in the Monongahela River. The Pennsylvania Department of Environmental Protection (PA DEP) began investigating TDS levels at points along approximately 70 stream miles on the Monongahela River from the West Virginia border to the confluence with the Youghiogheny River. In response, the West Virginia Water Research Institute (WVWRI) spearheaded a long-term water quality monitoring program in the Monongahela River Basin to identify sources and potential remediation options. The team found that modulation of the discharge volume from acid mine drainage treatment plants along the river could control TDS and sulfate levels below SDWA limits. Operators of the AMD treatment plants implemented the newly developed discharge management plan. The monitoring program expanded in 2012 to include the Allegheny and Upper Ohio River basins, adopting the name Three Rivers Quest (3RQ).