How many undammed rivers remain in California?

It depends on whom you ask. After speaking to several experts, we came up with a short list, including the Smith, the Clavey, the South Fork of the Trinity and the Mattole.

According to Ron Stork, senior policy advocate for Friends of the River, only one river in the state is undammed from source to ocean: the Smith River, tucked up in the northwest corner of California near the Oregon border.

But the Smith isn't the only answer we got.

"The Cosumnes is the only major river that I know of that does not have a major dam on it," said Eli Ilano, deputy forest supervisor for the Tahoe National Forest, raising the question of what's considered a "major" river.

"There is a small dam on [the Cosumnes]," Steve Rothert, the California Director at American Rivers pointed out. "I think it's now sort of defunct, but it does have a dam on it."

Instead, Rothert pointed to a small tributary of the Tuolumne. "Many people consider there to be one river that's not dammed in California, and that's the Clavey River."

Others suggested the Mattole in the Lost Coast and the South Fork of the heavily dammed and diverted Trinity River.

It all depends what your definition of "dam" is, said Jeanine Jones, interstate resources manager for the California Department of Water Resources. "There are some rivers that people conventionally speak of as being "undammed," but in fact have some small diversion dams on them."

It also depends on what your definition of "river" is.

"In some respects this issue is a little bit harder in California because of our very climate and the fact that we do have some rivers that are very wet and some that are basically ephemeral streams," Jones said.

"Anyway you cut it," said Stork of Friends of the River, "we dammed a heck of a lot of rivers."

Produced by Don Clyde and Lisa Pickoff-White