The Los Angeles County Flood Control District on Oct. 11 petitioned the U. S. Supreme Court to review a Ninth Circuit Court ruling. If the Supreme Court takes on this issue, judges would decide if navigable waters under the Clean Water Act (CWA) encompass only natural waterbodies.

The Ninth Circuit Court found the district liable for stormwater pollution that originated from upstream dischargers but was conveyed within the San Gabriel and Los Angeles rivers. The court stated that highly channelized portions of these rivers flow into natural areas and should be treated as outfalls subject to permit violations. However, the district argued that alterations to a river do not change its designation as a navigable waterbody under the CWA, and thus points where manmade sections terminate cannot constitute outfalls.