Groundwater-quality and select quality-control data from the National Water-Quality Assessment Project, January through December 2015, and previously unpublished data from 2013 to 2014 - Arnold, Terri; Bexfield, Laura; Musgrove, MaryLynn; Stackelberg, Paul; Lindsey, Bruce D.; Kingsbury, James; Kulongoski, Justin; Belitz, Kenneth (Data Series, 2018)