The Army Corps of Engineers believed otherwise, but the federal Environmental Protection Agency has declared the L.A. River, shallow and concrete as so much of it is, a navigible waterway and subject to the legal protections that come with that designation.
The L.A. Times lays out why some residents might wonder about the designation:
The decision may seem odd to people who know the L.A. River as a flood-control channel of treated water a few inches deep flowing between massive, graffiti-marred concrete banks strewn with rotting garbage and broken glass, and occasionally polluted with chemicals illegally dumped in storm drains and gutters that empty into it.
But it turns out literally being navigable isn't what the EPA decision is really about:
The EPA considered factors beyond whether the river's flow and depth can support navigation from its origins at the confluence of the Arroyo Calabasas and Bell Creek in the San Fernando Valley all the way to San Pedro Bay, a distance of about 51 miles.
Among other considerations, EPA officials said, were recreational and commercial opportunities, public access, susceptibility to restoration, and the presence of ongoing restoration and educational projects.
The designation overturned an earlier ruling by the Army Corps of Engineers that only four miles of the river were navigable, which would have made it easier to develop its upper reaches by eliminating the need for certain federal permits.
Southern California Public Radio has a thorough explanation of the legal meaning of the EPA's decision, and what led to it:
The magic phrase [navigable waterway] invokes the primary law regulating water pollution in the United States. Jackson says restoration plans, use of the river by watercraft and other factors make clear that the L.A. River must meet the Clean Water Act's strict standards for surface water quality. "It means that the entire 51-mile watershed is protected and it means that areas like Compton Creek will have the full protection of our nation's clean water laws."
That protection was in doubt after the U.S. Supreme Court moved to narrow the Clean Water Act four years ago. The court's decision in a case called Rapanos v. United States confused federal agencies and Western states where snow-fed spring rivers dry up in summer heat. When a rancher sought to fill in some mountain streams that feed the L.A. river, the U.S. Army Corps of Engineers proposed that the river, most of it, wasn't a body of water at all - just concrete used for flood protection.
Then two years ago activist kayaker George Wolfe led a flotilla down river, documented in videos. With kayaks and canoes, Wolfe said he was navigating the river to defend the right of the people of Los Angeles to use it. The Army Corps was not amused. A helicopter clocked yellow and orange boats from above. Get out of the river.
Boaters reasoned if they could float downstream, so could dirty runoff. EPA agreed - calling this river a special case, it took control.