Refers collectively to the main federal law for protecting water quality (33 U.S.C. §§1251 to 1387). This is the principal law governing pollution of the nation's rivers, lakes, estuaries, and coastal waters. Originally enacted in 1948 as the Federal Water Pollution Control Act (P.L. 80-845), it was totally revised by amendments in 1972 that gave the Act its current name and shape (P.L. 92-500). The objective of the Act is the restoration and maintenance of the chemical, physical, and biological integrity of the nation's waters. The Act is implemented by the Environmental Protection Agency in partnership with state and local governments. programmes in the Act have been primarily directed at managing point source pollution (wastes discharged from industrial facilities, sewage treatment plants, and municipal storm sewer systems). Agricultural activities have been less of a focus, but some may be affected by the Clean Water Act. The act established the NPDES system for pollution permits and the nonpoint source provisions of §§208 and 319 which deal with agricultural runoff. Large confined animal feeding operations are treated like industrial sources and are subject to permit requirements. programmes to manage nonpoint source pollution (rainfall runoff from farms, rangelands, forests, etc.) may affect agriculture. However, irrigation return flows are specifically exempt from regulation. A programme in the Act that regulates discharges of dredged and fill material into wetlands (Section 404) requires permits for activities on agricultural wetlands.