Evaluated extensive PFAS dataset that includes groundwater, surface water impoundments, wastewater treatment plant influent/effluent, groundwater treatment system influent/effluent, outfalls, and stream and river samples to determine impacts of site discharges to surface water quality. Analysis of PFAS chemical signatures and hydrogeologic details enabled attribution of PFAS present beneath the site to have originated from another AFFF an AFFF located upstream of the site via groundwater-surface water interaction.