WINTER PARK, Colo. (CBS4) ― Tumbling off a mountainside near Winter Park, Jim Creek carries a healthy volume of snowmelt until it flows smack into a concrete structure.

The structure does its job well. On the downstream side, all that's left is barely a trickle.

Jim Creek is one of many tributaries to the Fraser River. In this valley, Denver Water operates dozens of diversion structures that siphon water from what would naturally flow in the Fraser. The big utility now wants approval to take even more water and pipe it to Denver as part of its Moffat Firming Project.

Recreation and tourism would suffer if the stream is further imperiled, says Klancke who's president of the local chapter of Trout Unlimited.

"This river is struggling for survival," Klancke said. "An additional withdrawal could put it over a tipping point where it may not survive."