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• Board Meeting Date: 5/21/2008
• Description: ISF Section - Injury with Mitigation - Case No. 5-07CW210; Application of Vail Associates, Inc. and the U.S. Forest Service
• Board Meetings - Doc Type: Memo

hours per day beginning on November 1St and ending on December 31St. The actual start and
finish dates and hours of pumping for snowmaking operations would vary from year to year
depending upon when air temperatures become consistently cold enough for snowmaking
operations. Under optimal conditions, allowing well pumping to occur for 10 hours per day, the
desired snowmaking would be completed in a period of about 36 days. Under normal operating
conditions, it is likely that there will be intermittent 1 to 3 day periods of sub-optimal conditions
when no pumping would occur, allowing the streamflow to recover to near natural conditions.
The potential reduction to the ISF during well pumping would fluctuate from approximately
0.009 cfs to 0.019 cfs.
The one acre-foot of water pumped from the Tea Cup Bowl Well is assumed to be 100%
consumptive to Two Elk Creek and the Eagle River at the time of diversion, with 80% of the
snowmaking diversions returning to Two Elk Creek and the Eagle River during the ensuing
spring and summer. During winter snowmaking operations, it is expected that there will be a
small amount of return flows to Two Elk Creek, which are not included in Applicant's analysis
Benefits of mitigation
At the Board meeting, Mr. Robert Weaver of AMEC Earth and Environmental, Inc. (previously
Hydrosphere Resource Consultants) will give a presentation on (1) the reduction of impacts on
Two Elk Creek resulting from limitations on the well operation and (2) benefits to the natural
environment resulting from Vail Associates' stream restoration and habitat improvement plans.
The U.S. Forest Service has conducted a biological evaluation and biological assessment to
evaluate potential impacts of the proposed Tea Cup Bowl Well on sensitive and endangered
species. Based upon this evaluation, the Forest Service East Zone Fisheries Biologist
characterized the Two Elk Creek fish and macroinvertebrate communities as "robust" and
concluded that the proposed well and snowmaking operations would not result in a measurable
change in habitat for the Colorado River cutthroat trout (Healy 2007). The Fisheries Biological
Evaluation and Decision Memo documenting the Forest Service approval of the Tea Cup Bowl
Well is included in Applicant's proposal to the Board, attached to this memo in Exhibit 1.
Fishery and hydrology studies for Two Elk Creek and other similar high elevation streams have
found that the critical factor for trout populations is limited adult habitat due to low-flow
conditions during the mid-winter months of January and February (Bio/West 1990). Based upon
this assumption, the operational regime outlined above has been designed to assure that
snowmaking operations are complete and that the flow in Two Elk Creek will return to natural
flow conditions prior to the critical mid-January through February low-flow period. In addition,
the amount of flow reduction during snowmaking operations will be effectively reduced, or
buffered, through the use of alternating 10 hour pumping with 14 hour recovery periods, such
that the impact of snowmaking operations will not reduce the flow in Two Elk Creek below the
levels expected to occur during the critical low-flow period.
Alternatives
The proposed Tea Cup Bowl Well will provide snowmaking coverage for the areas surrounding
the base of the Tea Cup and Skyline Express ski lifts. The Skyline Express Lift (Chair 37)
provides the primary access point for Blue Sky Basin portion of the Vail Ski Area, which
includes approximately 20% of the ski area's total available skiable terrain. Because of a variety
of factors including high skier traffic, sun exposure, and relatively low elevation, the natural
snowpack in the areas around the base of these lifts is often insufficient to support consistent
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