A proposal to increase winter flows on the lower Fryingpan River could have big benefits for downstream trout populations.
The Colorado River District is proposing to the Colorado Water Conservation Board a one-year, renewable lease of some of the water it owns in Ruedi Reservoir to boost winter flows in the Fryingpan. CWCB staff presented the proposal to the board at its May meeting in Salida.
Currently, the decreed instream flow rate between Nov. 1 and April 30 in the Fryingpan below Ruedi is a minimum of 39 cubic feet per second. Often, winter flows are higher than this, but in dry years they can hover around the minimum amount.
But 39 cfs is not enough to maintain a healthy food source for the Gold Medal fishery’s population of trout. The proposal seeks to boost the minimum flow to 70 cfs.
The proposal is a collaboration between the Colorado River District and the Roaring Fork Conservancy.
Heather Tattersall Lewin, watershed action director with the conservancy, explained that low streamflows, combined with frigid temperatures, can lead to the formation of anchor ice on the bottom of the river.
This ice has a negative effect on the population of aquatic insects, known as macroinvertebrates, which are food for the brown, rainbow, and cutthroat trout that call this 14-mile stretch of river home.
“When the water and air temperatures are both really cold, the anchor ice can scour the bottom of the river,” Tattersall Lewin said. “It can scrape the macroinvertebrates in that area and they can get moved downstream. The insect population is what we are concerned about because it’s the fish food.”
Extra water in the stream will prevent anchor ice from forming. The conservancy estimates that 56 days is the maximum amount of time the leased water would be needed during the winter.
“This is a great opportunity to manage water to the benefit of environmental and recreational needs,” Tattersall Lewin said.
Under the proposal, the CWCB would lease up to 3,500 acre-feet of Ruedi Reservoir water from the river district. It would cost $65.25 per acre-foot, plus a $400 application fee, which for the total 3,500 acre-feet would cost $228,775.
The river district owns a total of 11,413.5 acre-feet of water in Ruedi, with 7,500 acre-feet of that available for leasing. Of the total the river district owns, 5,412.5 acre-feet is to support flows for the endangered fish recovery program.
Colorado River District General Manager Andy Mueller said there are two reasons his organization decided to offer up their water for lease. The first is to improve the health of the river and its trout populations. The second is related to the business arm of the district.
“We are charged with maximizing our assets and our assets are pools of water in different reservoirs,” Mueller said. “In this instance, we are leasing water to the CWCB and they are paying our district’s enterprise fund to release that water. It’s a win-win from our perspective.”
The Fryingpan River is popular with anglers because of predictable hatches that lead to fish feeding frenzies and great conditions for dry fly fishing.
Colorado Parks and Wildlife supports the increased winter flows.
In a letter of support to the CWCB, CPW instream flow program coordinator Jay Skinner wrote, “recent history has taught us that more flow during the winter months improves fish habitat, increases spawning success and fry emergence for brown trout, promotes a more robust macroinvertebrate food base for fish and most importantly, addresses issues related to anchor ice formation and accumulation.”
The CWCB will consider the proposal for approval at its July meeting. If approved, the increase in flows could begin this winter.
Editor’s note: Aspen Journalism is collaborating with The Aspen Times, the Glenwood Springs Post Independent, the Vail Daily and the Summit Daily on the coverage of rivers and water. The Times and the Post Independent published this story in their print editions on Thursday, June 7, 2018.