25d ‎(2)‎

• Board Meeting Date: 11/18/2007
• Description: CWCB Director's Report
• Board Meetings - Doc Type: Memo

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The Blue River, the Snake River, the North Fork and Tenmile Creek are all tapped for snowmaking. In
some cases stream flows drop near and even below levels set by the state to protect the aquatic
environment to a '4-easonable" degree.
The Blue River between Breckenridge and Dillon Reservoir is another area hit hard by snowmaking
diversions. At times during November and December, flows in certain reaches don't meet state-mandated
flows because senior water rights trump the state's protective in-stream flow rights.
Low flows also exacerbate the impacts of pollution from mines and other sources. When there is less
clean water available for dilution, concentrations of toxins like heavy metals increase. The cumulative
impacts from those simultaneous diversions across the Blue River watershed have never been fully
evaluated and disclosed publicly.
Water quality has improved in Straight Creek, where local groups and the Colorado Department of
Transportation have made a concerted effort to reduce or capture highway traction sand.
But other streams in the county, notably the pristine North Fork of the Snake River, are completely off the
radar screen when it comes to controlling sediment buildup.
Fine-grained highway sand can degrade the stream-bottom habitat needed by trout to spawn, and also kills
acres of wetlands and forests by choking the roots.
The North Fork, providing some of the cleanest dilution flows to the impacted Snake River, is marked in
scores of places where traction sand spills off U. S. Highway 6 nearly unchecked. The impacts range from
the alpine zone near Loveland Pass, where high elevation willow wetlands are turning to desert, on down
to the steep canyon between Arapahoe Basin and keystone, where sand spills have covered acres of
forested ground.
Sediment runoff is also an issue at Summit County ski resorts. The Forest Service and ski area operators
work hard to try and control the impacts from ski trail clear cuts and service roads, but often struggle to
meet the agency's own stream standards.
Similar issues are widespread across National Forest lands in Summit County, where runoff from
unpaved roads impacts numerous streams. Many Forest Service roads do not meet the agency's own
construction and maintenance standards. Walking along Forest Service roads in areas like Montezuma
makes it clear that the agency doesn't come close to having a handle on controlling runoff from the far-
flung network of backcountry roads.
A dramatic increase in logging during the next few years will exacerbate this problem unless logging
roads are monitored and maintained to the highest possible level. And the vast areas of dead forest left in
the wake of the pine beetle infestation will present another huge water quality challenge.
Trans-mountain diversions to the Front Range mean that the Blue River below Silverthorne often flows at
near-minimum levels for extended periods of time. The river always meets the state-set instream flow, but
that level (about 60 cfs) may not be adequate to sustain a healthy aquatic ecosystem in the long run.
Optimizing habitat for trout means mimicking the natural flows at least to some degree, with rising flows
in the spring and early summer, in order to provide good spawning and growth conditions for fish.
During the past few years, there has been enough water in the system to meet these needs to some degree,
and Denver Water has worked hard to balance its domestic water needs with recreation and
environmental concerns.
Flood Protection • Water Project Planning and Finance • Stream and Lake Protection
Water Supply Protection • Conservation Plaiming