SUMMIT COUNTY — A plan by Denver Water to increase water diversions from the West Slope to the Front Range will get an early December public hearing in Summit County.

As described in a draft environmental study, the Moffat Collection System project in Grand County would also have impacts on flows on the Blue River.

Flows in the Blue River at its confluence with the Colorado River could be cut by as much as 4,800 acre feet annually, about 2 percent of the river's flow, according to figures released by the U.S. Army Corps of Engineers in the draft study.

Denver Water project manager Travis Bray said those figures apply when at full build-out of Denver Water's existing system, and with the Moffat Tunnel on-line.

Under the new configuration of diversions that would result from the Moffat Tunnel project, Denver Water would take between 4,000 and 5,000 acre feet of additional water from Dillon Reservoir each year.

Bray said the draft study shows there would only be a negligible long-term impact to boating and no impact to fisheries in the Blue River.

Peak flows

Although 2 percent doesn't sound like much, peak flows are important for the river's ecosystem, said Becky Long, water caucus organizer with the Colorado Environmental Coalition.

“If the project goes forward, the Blue River would see reduced flows in the summer months during wet and average years,” she said. The peak flows in wet years help flush sediment out of the river, create new habitat and support rafting and kayaking, she said.

The main focus of the project is on increased diversions from the Fraser River, but conservation groups are concerned about overall effects on the entire Upper Colorado ecosystem. They advocated for the Summit County hearing when the draft study was released a few weeks ago. Long said the Corps was responding to requests from Summit County residents by scheduling the local hearing.

Bray said Denver Water is working with Western Slope stakeholders to address and mitigate impacts from increased diversions as part of an oft-touted global solution.

Those talks are independent of the current Moffat review.

The enhancements could include things like cash payments for water treatment or for habitat improvements.

“We don't just want to come in and do the bare minimum,” he said, adding that Denver Water's board is intent on working cooperatively with Western Slope entities on these issues.

Environmental goals

Conservation groups have identified several broad environmental goals that should be included in the project's mitigation plan, including:

— Adequate baseline flows in the Fraser throughout the year to sustain fisheries and recreation.

— Sustained peak flows at key times of the year to mimic a natural flow regime and ensure the health and resilience of the river

— Aggressive urban water conservation and efficiency measures to save more water, such as incentives for homeowners to replace Kentucky bluegrass with drought-tolerant landscaping. More than half of residential water use goes to watering lawns.

— Ongoing monitoring of the river's health and a mitigation plan with the flexibility to adapt to changing conditions.

Colorado Trout Unlimited, a cold-water fisheries conservation group, wants to make sure the big picture is considered.

“Front Range residents must recognize the connection between our water use and the health of our rivers and streams, fisheries and wildlife habitat,” said Colorado Trout Unlimited director Dave Nickum. “We can't continue to take and take from these rivers without accounting for our impacts. The glass is not even half full. It's almost drained dry.”

A summary of the draft environmental impact statement is online at:

http://bit.ly/5hy4hq