Schure paddles the Los Angeles River

LOS ANGELES (CNN) -- A river runs through the heart of one of the largest metropolitan areas in the world.

But in spite of an urban jungle which surrounds much of the waterway, in some stretches the Los Angeles River resembles a more natural stream.

In fact, the river is home to many wildlife species, which some local citizens are working hard to protect.

"We've identified over 150 species of birds, magnificent great blue herons, snowy egrets, other varieties of herons, cormorants, every sort of water bird," says Dennis Schure, paddling along a section of the river with flocks of birds on the water and forests of green on the banks.

Schure is a member of a small group trying to restore the river, a big job considering most of its 50-plus miles were encased in concrete 60 years ago to protect the city from floods.

"When you look at it from above, it looks like a nasty horrible scar that divides the city, that people don't like to look at or acknowledge, and made into a joke in some cases," says Melanie Winters of Friends of the L.A. River, a grass-roots organization involved in protection efforts.

It also served as a backdrop for Hollywood movies like "The Terminator."

Most of the river looks like this

"For a discharge from a publicly owned treatment plant perspective, I think it's a good thing, because it helps increase the beneficial uses of the L.A. River," says Jim Langley, an official with the city of Los Angeles.

The water may not be clean enough to drink, but for swimming, boating and other recreation, it does meet water quality standards.

"The highly treated water that comes out of the plants there has created or helped facilitate a wonderful community resource," says Felicia Marcus of the U.S. Environmental Protection Agency.

And for the Los Angeles River, almost anything is an improvement.