Nastri

The United States Environmental Protection Agency (“EPA”) required California to identify the Garcia River as a water body with insufficient pollution controls and, as required for waters so identified, to set so-called “total maximum daily loads” (“TMDLs”) — the significance of which we explain later — for pollution entering the river. Appellants challenge the EPA’s authority under the Clean Water Act (“CWA” or the “Act”) § 303(d), 33 U.S.C. § 1313 (d), to apply the pertinent identification and TMDL requirements to the Garcia River. The district court rejected this challenge, and we do as well.

CWA § 303(d) requires the states to identify and compile a list of waters for which certain “effluent limitations” “are not stringent enough” to implement the applicable water quality standards for such waters. § 303(d)(1)(A). Effluent limitations pertain only to point sources of pollution; point sources of pollution are those *1126 from a discrete conveyance, such as ‘a pipe or tunnel. Nonpoint sources of pollution are non-discrete sources; sediment run-off from timber harvesting, for example, derives from a nonpoint source. The Garcia River is polluted only by nonpoint sources.…