[Utilizer]

Local explanation here:

http://plumasnews.com/index.php/14354-mountain-meadows-reservoir-empties-stranding-fish

Workers unclogged an outlet valve plugged with debris and caused the drainage.

[RedHeeler]

Folsom Lake and Mountain Meadows(Walker Lake) are about 250 miles apart.

[RedHeeler]

Folsom Lake and Mountain Meadows(Walker Lake) are about 250 miles apart.

[JediJones]

But the actual reason appears to be bureaucratic red tape and regulations preventing them from closing the valve without "permission" which never came.

Then on Sept. 13, PG&E workers, performing routine maintenance, cleared debris from an outlet valve at the reservoir and left the valve open while waiting for permission to close it, according to Myers.