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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

Linda J. Bassi April 29, 2008
Page 9
Fishery and hydrology studies forTwo Elk Creek and othersimilar high elevation
streams have found that the critical factorfor trout populations is limited adult habitat due
to low-flow conditions during the mid-winter months of January and February (Bio/vllest
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.
The average flows in Two Elk Creek below Tea Cup Bowl are estimated at 1.25 cfs and
1.05 cfs, respectively, as shown in Figure 5. The critical low flow month is February,
with an estimated average flow of 0.79 cfs. The maximum well pumping impact of 0.019
cfs (Table 1) would reduce the average November and December flows to 1.23 cfs and
1.03 cfs, respectively. The flows in Two Elk Creek below Tea Cup Bowl, with the
maximum well pumping impact, are therefore expected to be well above the 0.79
average low flow conditions that occur naturally during late January and February.
As furtherassurance, stream improvement structures to enhance fish habitat during low-
flow periods will be installed and maintained in Two Elk Creek in the most affected
stream section. During the development of the Blue Ski Basin area, the Forest Service
required special measures to protect stream habitat in Two Elk Creek and to avoid any
disturbance to riparian areas and wetlands along the creek. The design and
construction of stream habitat improvement measures will therefore need to be
compatible with the environmental sensitivity of these areas. For example, it may not be
practical to utilize heavy equipment for construction, so alternative approaches may be
required.
The operational limitations detailed above, combined with the proposed habitat
improvement measures and the use of water efficient snowmaking equipment, will
effectively protect and preserve the natural environment of Two Elk Creek to a
reasonable degree.
Identification and feasibility analysis of other alternatives and discussion
of the reasonableness of each alternative considered
The proposed Tea Cup Bowl Well, as detailed above, would 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 skiertraffic,
sun exposure, and relatively low elevation, the natural snowpack in the areas around the
base of these lifts is often not sufficient to consistently support skiing and lift access
throughout the ski season. Without skier access to the Skyline Express and Tea Cup
Express Lifts, the entire Blue Sky Basin and Tea Cup Bowl areas must be closed to
skiing.
AMEC Earth and Environmental, Inc.