Abstract
The West Virginia Water Research Institute (WVWRI) has been monitoring water quality in the Monongahela River basin since 2009 through its Three Rivers QUEST (3RQ) initiative. This study examined 3RQ data for trends in the water quality of the Monongahela River basin. Water quality was monitored at 18 sampling locations in the Monongahela River basin with six locations on the main stem and 12 locations on main tributaries. Temperature, pH, electrical conductivity (EC), dissolved alkalinity, dissolved sulfate (SO4), and dissolved analyte concentrations (aluminum (Al), calcium (Ca), chlorine (Cl), iron (Fe), magnesium (Mg), manganese (Mn), and sodium (Na)) were measured during 2009 to February 2023. Total dissolved solids (TDS) and acidity were also estimated. Mean daily discharge at the time of water quality sampling was recorded from a United States Geological Survey (USGS) gage when available and calculated when needed. Four nonparametric statistical tests were performed to determine if there were significant monotonic trends over time: i) Mann-Kendall trend test, ii) Mann-Kendall trend test adjusted for discharge, iii) Seasonal Kendall test, and iv) Seasonal Kendall test adjusted for discharge. Slopes of significant relationships (α = 0.1) were estimated by the Theil-Sen estimator. Of the six mainstem sampling locations, widespread decreasing trends in TDS, SO4, Cl, and Na were observed, regardless of adjusting for discharge or season; similarly, increasing trends or no trends in pH were observed at all sampling sites. Many of water quality gains are likely related to the voluntary management plan that was implemented by the coal industry. This independent monitoring through 3RQ is important to communicate the impacts as well as plan for future water management.
