title: Unconventional natural gas development did not result in detectable changes in water chemistry (within the South Fork Little Red River).
abstract: The Fayetteville Shale within north central Arkansas is an area of extensive unconventional natural gas (UNG) production. Recently, the Scott Henderson Gulf Mountain Wildlife Management Area (GMWMA) was leased from the state of Arkansas for NG exploration, raising concerns about potential impacts on water resources. From November 2010 through November 2014, we monitored four reaches of the South Fork Little Red River (SFLRR), within the GMWMA, establishing baseline physico-chemical characteristics prior to UNG development and assessing trends in parameters during and after UNG development. Water samples were collected monthly during baseflow conditions and analyzed for conductivity, turbidity, ions, total organic carbon (TOC), and metals. All parameters were flow-adjusted and evaluated for monotonic changes over time. The concentrations of all constituents measured in the SFLRR were generally low (e.g., nitrate ranged from <0.005 to 0.268 mg/l across all sites and sample periods), suggesting the SFLRR is of high water quality. Flow-adjusted conductivity measurements and sodium concentrations increased at site 1, while magnesium decreased across all four sites, TOC decreased at sites 1 and 3, and iron decreased at site 1 over the duration of the study. With the exception of conductivity and sodium, the physico-chemical parameters either decreased or did not change over the 4-year duration, indicating that UNG activities within the GMWMA have had minimal or no detectable impact on water quality within the SFLRR. Our study provides essential baseline information that can be used to evaluate water quality within the SFLRR in the future should UNG activity within the GMWMA expand.
authors.affiliation: Biological and Agricultural Engineering Department, University of Arkansas, Fayetteville, AR, USA. bjaustin@uark.edu.
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Austin
authors.affiliation: Arkansas Water Resources Center, UA Division of Agriculture, Fayetteville, AR, USA.
authors.forename: Erin
authors.initials: E
authors.lastname: Scott
authors.affiliation: Engineering Freshmen Program, University of Arkansas, Fayetteville, AR, USA.
authors.forename: Leslie
authors.initials: L
authors.lastname: Massey
authors.affiliation: Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Evans-White
authors.affiliation: University of Central Arkansas, Conway, AR, USA.
authors.forename: Sally
authors.initials: S
authors.lastname: Entrekin
authors.affiliation: Arkansas Water Resources Center, UA Division of Agriculture, Fayetteville, AR, USA.
authors.forename: Brian E
authors.initials: BE
authors.lastname: Haggard
mesh_terms: D001131:Arkansas; D004784:Environmental Monitoring / Q000379:methods*; D008670:Metals / Q000032:analysis; D059206:Natural Gas; D009566:Nitrates / Q000032:analysis; D061329:Oil and Gas Fields; D045483:Rivers / Q000737:chemistry*; D013431:Sulfates / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*; D060753:Water Quality
chemical_list: D008670:Metals; D059206:Natural Gas; D009566:Nitrates; D013431:Sulfates; D014874:Water Pollutants, Chemical
keywords: LOESS; Natural gas; Trend analysis; Water quality