As used in this article unless the context requires a different meaning: “Clean Water Act” means the Federal Water Pollution Control Act, as amended, (33 U.S.C. § 1251 et seq.). “Fully supporting” means those waters meeting the fishable and swimmable goals of the Clean Water Act. “Impaired waters” means those water bodies or water body segments that are not fully supporting or are partially supporting of the fishable and swimmable goals of the Clean Water Act and include those waters identified in subdivision C 1 of § 62.1-44.19:5 as impaired waters. “Toxic impaired waters” means those water bodies or water body segments identified as impaired due to one or more toxic substances in the reports prepared pursuant to § 62.1-44.19:5. “Toxic substance” or “toxics” means any agent or material listed by the USEPA Administrator pursuant to § 307(a) of the Clean Water Act and those substances on the “toxics of concern” list of the Chesapeake Bay Program as of January 1, 1997.