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HomeMy WebLinkAboutcoa.lu.pu.Aspen Mountain master plan 1997 /"""" n \. Aspen 199 Mountain 7 Master Plan ~,.., ~. :" :t,' .... ' , I',:;;'.:~-'.... . "",. ...M .;;;;:. ',,'" "..,.,... '!:v .M ",. ." ;..- ~ 1"~.'~ . I, ,_~ , ;,.'/. .~~ ~ ~ ...-'f' '~" . . .w:'.' or. .'liiIW'lf 't:. /1.....'. ... ,0/' ''''''''''' .. M ......,.. t\."':.;~. .. ." ....l.l...:=..=a\ . ... . ~.,: .~~ ...~ ,." . ,~ . .'" ........ .~,'_a .....,.. .' r A u g U 5 t 1, 19 9 7 Revegetation Plans Photo of Aspen Mountain circa 1958 courtesy of Apen Historical Society , , \ .! ~. Memorandum To: Brent Gardner-5mith, Planner For Community Affairs Fram: John H, Sale, Planner DatcK 08/01/97 ReI AMMP Re-Vegetation Plan, Vegetation Management .~ , , Aspen Skiing Company Planning and Development Per the County's request, I have included the Aspen Mountain Re-Vegetation Plan including an illustration of the proposed sites, Most of these practices are in full implementation at this time, . Page 1 ,-, 1""'1 Aspen Mountain Re-vegetation Plan This re-vegetation plan is designed to satisfy the requirements of both the U,S, Forest and Pitkin County, Aspen Mountain has a long history of successful re-vegetation efforts. Knowledge acquired over the years on site will be applied to all aspects of implementing our re- vegetation plan, Due to the mining history and the industrialized conditions that were left behind, Aspen Mountain must take a very unique approach to its re-vegetation plan, Considering that there is very little nutrient top soil available on the mountain, the degree of success for re-vegetation must be evaluated differently than other ski areas, Problem areas targeted for re-vegetation will be classified into one of the three categories below, Category I Problem areas that fall within this category are typically "cosmetic" repairs, Generally, this includes previously seeded areas that need additional seeding or the seeding and mulching of patch areas, The procedure for this category include seeding, mulching and the application of an organic fertilizer, Example: An exemplary site of Category I would be the Spar Gulch area. Overall this area is well vegetated, although there are many patches and bare spots noticeable in high visibility areas, Category II Areas that fall into this category are light erosion zones, previous construction sites, and compacted bare spots. While these areas are not critically serious they may need some mechanical equipment to properly re-vegetate the area The procedure for this category include scarifying the soil, seeding and apply organic fertilizer, and mulching. Additional top dressing may be needed to properly re- vegetate the area, Example: A prime example of Category II would be the area surrounding the base of the Shadow Mountain Lift (# I-A), This area needs more attention and because it is a high use area for both foot and vehicle traffic, The soil needs to be scarified and top dressing will provide the nutrients and base for the seed mix. ' r'" ~ CategorY III Problem areas that fall into this category are site intensive and are serious undertakings, Many of these areas will include re-grading and large quantities of soil, and structural support may be required for stabilization, Procedures for this area will require re-grading of terrain, hauling of additional top soil, seeding and mulching and application of organic fertilizer, Example: One project slated for Category III would be the slope of the Little Nell Hotel that faces the Gondola terminal at the base of Aspen Mountain, Although this area would be typically considered Category I, we feel that due to its visual exposure, a total re-veg project would be most beneficial to the enhancement of the co=unity, This site would require a small irrigation system and the import of top soil to provide a home to a mass planting of Colorado wild flowers, *See figure 18, Re- Vegetation Plan of the 1997 Aspen Mountain Master Plan, This figure graphically illustrates the location of problem sites and are broken down into the three categories described above, The Aspen Skiing Company proposes to take on one extensive re-vegetation problem area per year, The selected area, depending on which category the area falls into will be completed within the summer months, Each selected area will vary in size and complexity, one year may cover a large area of Category I and the next year a small but intense Category III area, ASC wishes to address the issue ofre-vegetation head on and commit the resources needed to implement a working plan, At this time the Aspen Skiing Company is engaged in extensive Vegetation Management Plans for, both the Aspen Highlands and the Snowmass Ski Area, These studies are being conducted by Westem Bionomics, LLC, ofFt. Collins, Colorado with the approval of the White River Forest Service, ASC is preparing to study Aspen Mountain and Buttermilk in the 1998 fiscal year, The scope of work will address a total Vegetation Management Plan and will include timber re-vegetation and clearing, The vegetation management plan will be coordinated with a 1993 study prepared by the, Wildlife Habitat Enhancement Council entitled "Opportunities for the Enhancement of Wildlife Habitat and Environmental Awareness on Aspen Mountain," r". .!"'""\. Re-vegetation of the disturbed sites on Aspen Mountain will have four primary goals: 1, prevent soil loss and siltation of drainage as a result of removing forest cover; 2. establish vegetation that is compatible with existing native vegetation in appearance, composition, and permanence; 3, creating habitat that will support use by native wildlife; and 4, to provide quality skiing terrain. These goals will be accomplished by planting native grasses or species adapted to the area and using mulch to reduce soil loss and enhance the establishment of seeding, In areas with steep slopes and shallow or erodible soils, mulch will be used in combination with an erosion control mat or netting to provide further protection of soils and seedlings, Follow-up measures, such as additional seeding and/or fertilization, will be applied as needed, These measures conform to the Pitkin County Landscape Guidelines, which have been incorporated where appropriate throughout this revegetation plan, The native seed mixes listed below have been selected to provide visual diversity, prevention of soil erosion and ensure that a variety of feed materials are available throughout the growing season, Aspen Mountain Mix Name, Variety Streambank Wheatgrass, Sodar Slender Wheatgrass Tall Fescue Hard Fescue Creeping Red Fescue MountainBromegrass ' Orchardgrass, Paiute Canada Bluegrass Alsike Clover White Dutch Clover Timothy, Climas Red Top Percent 5% 5% 10% 10% 10% 15% 10% 10% 5% 5% 10% 5% *Fertilizer biosol or other suitable organic fertilizer only, No nitrogen fertilizer will be used. I""" 1""'\ All seed will be furnished from Garrison Seed Company, The seed bags have the appropriate information (name and address of the supplier, the seed names, the lot number, net weight, origin, percent weed content, the guaranteed percentage of purity and germination, and the pounds of pure live seed of each seed species) on them. All supplied seed will be free of noxious weed seeds, A signed statement certifying that the seed furnished is from a lot that has been tested will be made available, Seed, that has become wet, moldy or otherwise damaged in transit or in storage will not be used. During the process of clearing sites, both rubber-tired and tracked equipment will be used on slopes of 30 percent or less, On steeper slopes, only tracked equipment will be used, Damaged areas will be regraded to appropriate smoothness arid patched with soil material, if necessary, Seeding Procedure: Seedbed preparation will consist ofleaving a rough, irregular soil surface, This will include removing large rocks, Regardless of the mix of seed used, seed will be planted by broadcasting or drill seeding within ten days after soil disturbing activity has ended, Toward the end of the construction season, all areas will be evaluated and additional revegetation measures will be implemented as needed, Planting during the early fall will allow the seed to be fully moistened and worked into the soil by natural processes prior to germination in the spring, For some species, overwintering also enhances germination by weakening the seed coat. Seeding rates will vary because of seed size, method of seeding and site requirements, Seeding rates of 50 to 250 seeds per square foot, depending on seed size, will be used, Available plant nutrients are a necessity for any aggressive revegetation program that restores and maintains soil productivity resulting in healthy, vigorous vegetation, Generally, all vegetation responds favorably to the addition ofuitrogen and phosphorus fertilizers, A mixture of20-20-10 will be used as a supplement to assist revegetation, An application rate of 50 to 250 seeds per square foot followed by a second application of equal amount later in the growing season or the following growing season has been demonstrated to be most effective and efficient. ' ~ ("; The U.s, Forest Service will assist in the designation of additional control measures, if any are needed. These measures may include, but are not limited to silt fencing, sediment basins, check dams, berms, mulching, revegetation, or natural materials will be used to decrease energy and remove silt. r'" (', Mulching Procedure: Following seeding slopes with steepness less than 2:1 will be mulched with approximately 1,500 pounds per acre of straw, This straw or hay will provide the cover needed while still allowing sunlight to penetrate the mulch, wanning the soil and enhancing plant growth, Application is done either by hand placing or mechanically blowing the mulch, The straw will be crimped into the soil and, in areas subject to wind erosion, anchored with a tackifier, Areas with steepness greater than 2: 1 will be further stabilizer by using plastic netting or mat. A standard of 70 percent ground cover after the second growing season or the amount equal to the adjoining undisturbed areas, ifless than 70 percent will be used to determine reapplication, modification, or fertilization, The Forest Service will also monitor ASC's compliance with the re-vegetation specifications contained in the annual Summer Operating Plan, Reclamation Areas that will be reclaimed are building sites, structure placements, and landforms that will be moved, replaced or abandoned, Reclamation will consist of minor disturbances from grading the previously developed areas into the natural contours and revegetating, Appropriate and revegetation will occur within ten days after construction activities on site have been completed. Aspen Mountain Erosion Control Plan Aspen Mountain erosion and drainage plan was designed to protect the natural resources in the project areas. (There are no active year-round streams in the area, but there are two main drainages that are active in the run-off period and have the potential to. cause erosion, Currently, both are culverted where necessary and are well managed, The plan consists ot: for the most part, two measures, The first is the use of silt fences and erosion bales located at the toe of disturbed sites during the construction activities, The second control measure is an aggressive revegetation program described in the Revegetation Plan, Seeding and mulching will be enacted within ten days after the completion of the soil disturbing or construction activity, The specific erosion control measures are detailed on the revegetation and drainage plans. Other erosion control measures will be used throughout the area as needed, One specific measure is water bars. They will be installed at appropriate intervals along cleared ski slopes and roads to limit distance that sheet runoff can flow unchecked, The water bars will divert runoff into the adjacent uncleared forest whenever possible, Where appropriate, energy-dissipating structures,(i,e" rock, hay bales, or slash piles) will be installed to prevent erosion in the forest areas receiving the. diverted slope runoff. , ", :111IIII':':,.' .11'.':" .,11" .11II, .':' .'; ,',,": :..' " ". _....',.:....' :.,.', '. '" ";:'1":" ...,;,",:,IIIIIIII.,. ,',' 11>11II,' . ...,. '.'11I' ...':,..:. III'.:.,',." . ,.:'.,' I."" '" '11I'" " " '...".".',:,;',.".".:,"... ".. " ":' ,'~' ,)' " ::'" ,:' " , . " ',::'::, ,,' , ,>:", c,;!,': ' " ,,' ~< " <,' '.:.': II' ...,...:...,.:'.',.".:;.' 'B""" ,',..". . 11III':'11III'11IIII.": '-"'".,::,",:. 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',>','. '11IIIII'.," ", , "........,..., "" , " , r; ,. ,,<', ", ~,," . ~~~,.,..~tnf.rAIN 1997 Maae. Pia :.i D_~A .....-' 1997 S _loa J."" ..... C........ 1:. a J.OOO' r--1 '-"'...1 t 20' r---'1 ~ .,-" 1 9 9 7 Aspen Mountain Master Plan , "f ;;.... I -<. 'toJl.-;;:..' ,1'- t" ,A"", -;g.,.. ~. ", 'do .,_"'...t" "',"'.., ~~ IY ." ,... ~, z.-. ,'I, ;.,:' '.. '.w ~.. ........:~ .~n"'"l;;:'~':":'I"...." "0, -,.', "....,..,." III - ' ,.,. ,.'. '~~. .;..:., ,.-~.'''' .... ... . ....~~.-.... " .'". A u g u s t 1, 19 9 7 Snowmaking Analysis Photo of Aspen Mountain circa 1958 courtesy of Apen Historical Society AIJG 01 '97 11:53AM L RH :: .~. P,2 PRELIMINARY REPORT ON THE POTENTIAL IMPACT OF NEW SNOWMAKING AT ASPEN MOUNTAIN For Aspen Skiing Company Leonard Rice Consulting Water Engineers, Inc. August 1, 1997 AUG 01 '97 11:53AM L R~ E ~ ACKNOWLEDGMENTS The technical material in this report titled, "Preliminary Report on the Potential Impact of New Snowmakina at Aspen Mountain." dated AUliUst 1, 1997 was prepared by or under the supervision and direction of the undersigned whose seal as a Professional Engineer is affixed below: Leslie H. Botham, P.E, The following members of the Leonard Rice Consulting Water Engineers, Inc. staff' contributed to the preparation of this report: Principal Investigator: Hydrologist: Leslie H. Botham Jennifer Larson Technician: Katja Stringfield Technical Typist: Glenda Emmans Leonard Rice Consulting Water Engineers, Inc, P,3 RUG 0i '97 11:54AM L R~ E 1-.., P,4 PRELIMINARY REPORT ON THE POTENTIAL IMPACT or NEW SNOWMAKlNG AT ASPEN MOllNIAIN August 1, 1997 INTRODUCTION The Aspeli Skiing Company (ASC) proposes to increase the si~ of its snowmaking area on Aspen Mountain by approximately 56 acres. It now makes snow on about 180 acres. The new area is located above (south of) the existing snowmaking area, lying between elevation 10,370 and 11,180 feet, in Pitkin County, Colorado. The area is shown on Figure 1, and it is about 2.1 miles south of the City of Aspen, ASC estimates that it will deliver an average of 11 million gallons of water to the new snowmaking area per year, which will make about 18 inches of snow in November llJId December of most years. The purpose of this preliminary report is to qualitatively address the impacts that the proposed new snowmaking activity could have on storm runoff from the Aspen Mountain. BACKGROUND It is reported that ASC has been making snow on Aspen Mountain since 1983, Table 1 summarizes the amount of water which has been used in recent years to make snow on approximately 180 acres of trails and ski runs. The average water applied is 0,198 million gallons (MG) per acre, with a range from 0.102 to 0.297 MG per acre. With specific regard to the Sununer Ditch, which exports water from Spar Gulch to Keno Gulch, Wright Water Eugineers, Inc. concluded in 1989 that ASe's snOWInaking activities above the ditch u... would increase snoWInelt runoff and the diversion rate by approximately three percent." APPROACH Because of the limited time available for this study, it was necessary to make maxim.um use of existing information and to conduct qualitative investigations. For Spar Gulch llJId its tributaries, we were able to obtain and review two drainage stUdies: a) "City of Aspen, Urban RunoffMa.~ement Plan," by Wright-McLaughlin Engineers, Augwrt1973,and , b) the more recent "Aspen Mountain Lodge, 700 South Galena Street, Top of Hill and Ute City Place, Storm Drainage Report," by Rea, Cassens and Associates, Inc" July 1985, These reports identify the 2-year, S-year, and lOO-year storm flows for Spar Gulch, which contains the majority of the new snowmaking area. These values are summarized on Table 2. Leonard Rice Consulting Water Engineers, Inc. 8UG 01 '97 11:54AM L R~ E .~ P.5 preliminary Report on the Potential Impact of New Snowmaking August 1, 1997 Page 2 For Keno Gulch, we were able to obtain and review the draft report "Report on the Aspen Music School Debris Flow Investigaticn," by Wright Water Engineers, Inc., May 1996. Several approaches were undertaken for this investigation. The first was to quantifY the water equivalent of the snow to be added to Aspen Mountain, and compete it with estimates of historic waU.:r equivalent of the snow on the mountain, as indicated from historical "Snoo,l" snow course station dala. The second approach was to compute the average rates of flow which could result jf the water equivalent of the new snow was released from the mountain for a range of durations from one to 45 days. The results were then compared to published estimates of storm runoff for the mountain. The third approach was to utilize the methodology developed by Colorado Ski Country USA to compute the amount of runoff from the new artificial snow, The procedure is contained in a report titled "A Final Report on The Colorado Ski Country USA Water Management Researth Project," February 1986. The report has separately a bound "Handbook" and 1.'1 "Appendices" of the same date. TRmUTARY AREAS In this analysis, the areas of interest are defined as Spar Gulch and its tributaries (which deliver water from Aspen Mountain to the City of Aspen) and Keno Gulch whic;:h is above the Music School. The 56 acres ofnew snowmaking area occupy about 124 acres of land, In other words, new artificial snow will be made will be on ski trails and ski runs which themselves are within the larger area of about 124 acres, Of the 56 acres ofland, nine acres will be exported out orthe area of interest to the east, and another 4.6 acres will drain out of the area to the southwest, Two acres will drain to Copper Gulch, which is , tributary to Spar Gulch, and the remaining 40.4 acres drain to the "Summer Ditch," an interceptor clitdl which exports Spar Gulch flows into Keno Gulch, which is located to 'the west. See Table :3 and Figure 2, At the point where the Summer Ditch delivers water into the Keno Gulch basin, it is approximately 500 feet north of a landslide and debris flow which affected the Aspen Music School in May 1996. In its report, "Report on the Aspen Music School Debris Flow Investigation," May 1996, Wright Water Engineers, Inc. concluded on page 14, ..... although the Spar Gulch diversion water may have increased the fluidity of the Material, it was not the cause of the landslide or debris flow." Figure 1 and:3 of the WWE study show the relation of the lancls1ide area to the diversion ditch, and WWE's conclusions are included with the Backup for this report. Leonard Rice Consulting Water Engineers, Inc, AUG 01 '97 11:S5AM L R~ E /""""" P.6 Preliminary Report on the Potential Impact of New Snowmaking AugUst 1, 1997 Page 3 lithe Summer Ditch is considered fully effective, then the 40.4 acres of new snow area tributary to it constitute 8.1 percent of the 502 acre tributary area of the Summer Ditch and Keno Gulch. See Figure 3. If the capacity of the Summer Ditch was exceeded, or ifit failed, then l:Unoff' above it would remain in the Spar Gulch basin and continue down Spar Gulch toward the City of Aspen. Therefore, the other point of view in this report neglects the capacity of the Summer Ditch. In that case, 42.4 acres of new snow area (40.4 acres above the Summer Ditch + 2.0 acres tributary to Copper Gulch) constitute 6.S percent of the 657-acre combined Spar-Copper-Vallejo C-ulch tributary area above the City of Aspen, The two existing drainage studies mentioned above also disregard the interceptor ditch, See Figllre 4, WATER EQUIVALENT OF NEW SNOW Ase estimates that it will use an average of 11 MG of water to make artificial snow on the new area. This is equivalent to 7.23 inches of water over the 56 acres of new snow area. Based on historic operations, we estimate that the amcunt applied might rlUlge from 5.7 to 16.6 MG (see Table 1), The spray losses froM the initial application are estitnated to be is percent. So the water equivalent of the artificial snow which will be made is estimated to average 10,34 MG (6,80 inches), with a range from 5.4 to 15.6 MG, Tables 4 and 5 and Figures 5 and 6 summari%e the historical water equivalent of two SCS snow survey (Snotel) stations on Aspen Mountain. They.are named "Aspen" and "Lift,.. The Aspen gage was located near lift 3 at an elevation of about 9,700 feet. It was discontinued in 1984. The Lift gage is located east of the Sun Deck at an elevation of 11,250 feet. The data presented on Tables 4 and S, and on Figures 5 and 6 show the water equivalent of the snow on the gl.'OU.'1d on the first days of February, March, April, and May for the years Which we had readily available information. For the Aspen gage, the range of water equivalent is from 2.3 to 26.7 inches, The average values range from 9.9 inches on February 1st to 18.2 inches on May 1st. For the Lift gage, the range is from 2.9 to 33 inches, wifu the averages ranging from 11.3 to 20.2 inches, The average water equivalent of the new snow (after deducting 6% for spray loss) is' estimated to be 0,57 feet or 6.80 inches over the 56 a.cies of new snawmaking area. Expressed over the whole 502. acre tributary area of Summer Ditch and Keno Gulch, this is equivalent to 0.55 inches. See Table 6. This is from 3.0 to S.6 percent of the historical average first-of-month (February through May) water equivalent for the Aspen snow gage, and from 2.7 to 4.9 percent for the Lift pge. The water equivalent of the new snow when expressed over the 657-acre tributary area of Spar, Copper, and Vallejo Gulches, is equivalent to 0.44 inllheS. See Table 6. This is from 2.4 to 4,4 percent of the average monthly (February through May) water equivalent for the Aspen snow gage, and from 2,2 to 3.9 percent for the Lift gage, Leonard Rice Consulting Water Engineers, Inc. AUG 01 '97 11:56AM L R~ E .,-." P,7 Preliminary Report on the Potential Impact of New Snowmaking August I, 1997 Palle4 The Spar-Gulch-equivalent estimate is shown on Figures 5 and 6 for comparison with the historical water equivalent of snow on the mountain. Since the water equivalent of the new mow is such a small percentage of the snow which is already on the mountain, the effect of the new snow is expected to be negligible in terms of con1ributing to the stonn runoff which will be expected in either Spar Gulch or Keno Gulch. PossmLE SNOW.MELT RATES We also computed the average rates of flow which might result if the water equivalent of the new snow melted without any additional loss (like evapotranspiration or percolation) over periods of time ranging from one day to 45 days, The results are shown on Table 7 and on Figure 7. For any given duration, these rates of snowmelt would be conservative, since other losses would occur like sublimation, infiltration, and evapotranspiration, ASC representatives estimate that under normal conditions it would take about 7 days to melt 18 inches of snow at the altitude of the new snow area. Using this as a representative time, the rates of snowmelt are estimated to be 1,65 cfs to 2.49 cis for the Keno Gulch area, and 1.73 to 2.67 cis for the Spar Gulch area. See Table 7, The published stonn runoff amounts for Spar Gulch, and the estimated amounts for the Suuuner Ditch tributary area and Keno Gulch are summarized on Table 2. The estimates are based on the per-acre values for Spar Gulch. Considering the limitil'lg culverts at the end of the Summer Ditch as it exits the Spar Gulch basin (ie the IS-inch and 12-inch corrugated metal culverts), we estimate the capacity of the Summer Ditch diversion at less than 7 cfs, which is the estimated 2-year storm inflow. The capacit)" of the ditch itself is much more than this in most areas. The various ma"imum.year snowmelt rates for the Spar Gulch analysis are compared with the 2-year and 5-year storm runoff values for Spar Gulch on Figure S, From this analysis, it is clear that the snowmelt rates from the new snow are well below even the 2- year storm runoff values for Spar Gulch, or the combined Summer Ditch and Keno Gulch basin, EXPECTED RUNOFF FROM NEW SNOW Using the procedure outlined in the Handbook from the report "A Final Report on The Colorado Ski Country USA Water Management Research Project," February 1986, we estimated the volume and monthly distribution of runoft' fioom the new snow. The average water applied amounts to 7.23 inches over the 56 acres of new snow area. The 6% initial spray loss amounts to 0.43 inches of water. Prior to and during runoff an additional 1.25 inches otloss are expected, This leaves an expected total Leonard. Rice Consulting Water Engineers, Inc. AUG 01 '97 11:56AM L R~ E .~ P,8 Preliminary Report on thE: Potential Impact of New Snowmaking August 1, 1997 Page 5 runoff amount of 5,55 inches, The component parts are shown on Figure 9. Additional losses would be expected as the runoff travels down the mountain via Spar Gulch, otthrough the Summer Ditch and down Keno Gulch, The runoffpattem is expected to o~ur d\liini April through June, Figure 10 shows the rates oftlow which vvould resultjusr below the 40.4 acres of new snow area above the Summer Ditch. The average monthly rates of flow peak in April at 0.30 cu. Since this is well within the capacity of the Summer Ditch, we would expect that it would be conveyed to Keno Gulch. However, the ditch itself would be expected to leak, and there would be additional losses due to evapotranspiration along the ditch and within the Keno Gulch basin, so the peak flow at the mouth of Keno Gulch would be less than 0,30 cfs. The ~ted timing of runoff JUSt below the two acres ofnew snow area which are tributary to Copper Gulch are shown on Figure 11. The flow would peak in April at O.ol 5 cfs. Additional losses would be expected to occur durinil the flow path down Copper Gulch, This is a very small (neilligibie) rate ' of flow, which may not even make it to the confluence of Copper and Spar Gulches, let alone the mouth of Spar Gulch at the City of Aspen. OTHER CONSIDERATIONS It is believed that the storm runoff which will occur from Aspen Mountain will be generated by thunderstorm rainfall, rather than from snowmelt. This is addressed in the 1973 Wright-McLaughlin master plan, which shows that rainfall runoff is much greater than the snowmelt runoff f(lt selected areas. Thunderstorms are expected to occur in mid to late summer, after most of the snow has melted. It is also clear from the above analysis that the majority of the runoff from the new snow will occur during April, which is much earlier in the year, It is, however, possible for rainfall events to occur when snow is still on the ground. When this happens, the rain helps melt some of the snow, which then contributes to the runoff. The new snow will be among the first snow on the mountain. If a raiofall storm happened when there was plenty of snow on the mountain (several feet for example), then the new snow would not make any difference in the amount of runoff, since the snow on the top would be affected by the rainfall. If the rainfall storm happened when there was not much snow on the ground, then it Is possible that the new snow could make a difference in the amount of runoff which would occur. It is likely that the added snow will increase the time that snow is on the ground by a few days to possibly a week. This increases slightly the time that rain-on. snow storm events could OCcur, Leonard iUce Consulting Water Engineers, lnc, AUG 01 '97 11:57AM L RH E: ,~ P,9 Preliminary Report on the Potential Impact of New Snowmaking August 1.1997 Pap 6 CONCLUSION From the above qualitative analyses, we bellevethat the S6 acres ohewartificial snow which is proposed by ASC Will not have any significant effect on the runoff from the Aspen Mountain, either in the Spar OuIch basin, or the Keno Oulch basin. FUe: SNOWMELT.RPT Attachments: LRCWE Tables 1 through 7, LRCWE Figum 1 though II, and LRCWE Backup (24 pages). Leonard Rice Consulting Water Engineers, Inc. AUG 01 '97 11:57AM L R~ E ~ Aspen Sl<ling Company Preliminary Table 1 estimate of Water U...dfor existing Snowmaking Operations On Aspen Mountain Less Remainder November water Average Use Assumed for Projected Through Purchased @ Ruthie's Snowmaklng on Snowmaklng on January From Aspen Restaurant 180 EXISTlNG ACRES 58 NEW ACRES (Million Gallons) I MWACra (Million Gallon~ 1983-84 18.S50 -0.276 18.374 0,102 5.116 1984-85 19,560 -0,216 19,284 0,107 5,999 1985086 2U16 -0,276 28.5040 0,159 8,879 1986.87 30.222 -0,276 211,946 0,166 9,317 1987-88 38,250 .0,276 37,914 0,211 11.814 1lil88.89 37,146 .0,276 37.470 0.206 11.657 1989.90 ' 52,992 .0,276 52,116 0.293 16,401 1990-91 39.546 .0,276 39.270 0,218 12,217 1991-92 40,738 -0,276 40,462 0,225 12,588 1992.93 45,996 -0,276 45,120 0,254 14,224 1993.94 53,710 .0,216 53,434 0,297 16,624 1994.95 24,672 -0,276 24,396 0.136 7,590 1995.96 37,813 -0,276 37,337 0,207 11.616 199MI7 34,116 -0.276 33,840 0,188 10.528 . Average 35,1102 -0,276 35,626 0,198 11,084 Maximum 53,710 .0,276 53,434 0.297 16,624 Minimum 18,650 .0,276 18,314 0.102 5,716 Notes, Constants, and Calculations; 01-Nov First day for restaurant's water use 31.Jan Last day for restaurant's waler use 92 oays for restaurant water use 30,000 Gallons used for restaurant use every 10 days, 180 Aores of existing snowmaklnll area . 58 Acres of new snowmaklng area Leonard RIce Consulting water Engineers, Inc, ( Printed 31..Jul-97) P,10 July 30, 1997 = 34,01 AcFt = 51,02 AcFt .. 17,54 AcFt File: Snow_RO.WB1 AUG 01 '97 11'S8AM L R ?""\ E ,........" P,11 Aspen Skiing Com~v Preliminary July 30, 1997 Table, 2 Summary of Reported & Estimated Storm Runoff Amounts , Tributary 2.Year Runoff 5. Year Runoff 10o-Year Runoff ellSin 10 & OesCription EnginHr Year Area (Acres) (Cf'8) 1 (AcFt) (CI'l:l) I (ACl't) (Cl'lI) I (Acf't) 1A (Spar Gulch 0 Elev 8,000') Wright-Mclaughlin (a) 1973 590 22 3,1 302 27,4 A,S&C (Copper & Spar Gulches) Ree.cas&ens (b) 1985 551.8 10.2 32.8 195,4 ~B,C,O,&E (Spar@ L Nell) Rea.calsens (b) 1985 879,3 15.6 4e.Q 314,9 Keno Gulch Natural Basin LRCWE (c) 1997 254 8 17 124 Summer Gulch Intercepted Area lRCwe (c) 1997 248 7 17 121 <II) "City of Aspen, Urban Runoff Management Plan," Augusl1973, (b) "Aspen Mountain Lodge, 700 Soulll Galena Street. Top of Mill ane! UleCity PlaCII, Storm Water Drainage Repllrt," January 1985, (c) Very preliminary estimate by leonard Rice Consulting Water Engineers basad on un~ values by Wright-Mclaughlin & Rea-C$S$ens, Leonard Rice Consulting Water Engineera, Inc, ( PrlnllCl31.Jul.97 ) File: Sno\'U~O.WB1 AUG 01 '97 1l:58AM L R ~,E .--- Alpen Skiing Company Preliminary Table 3 Summary of Tributary Area. (Acres): Keno Gulch at Cutlt Creek- 254 Natural tributary area 248 Imported from Spar Gulch via Summer Ditch 502 Total Sl)ar, Copper,and Vallejo Gulch..- 183 copper Gulch's tributary area 344 NIItural tributary of Spar G above Copper G 83 Spar Gulch balow Copper G, at Little Nell Run 47 SlIVer Queen Area at Lltl1e Nell Run 657 Total Spar and Copper Gulch. .248 Spar G expcrted to KenoG via Summer 0 409 Total Spar & Copper less exported Summer D 8nowmaking Area- 9,0 Out of Buin to the East 4,6 Out of Basin to the Southwest 2,0 Tributary to Copper Gulch 40,4 Tributary to Spar Gulch & Summer Ditch 56 Total 56 Oneok against acres of new snowmaklng area 124,5 Area that the 56 acres of new snowmaklng occupies New Snowmakin Area Bar Graph: Percent of Total 50.60% 49,40% , IlO,OO% 27,85% 52,:38% 12.63% 7,15% 911,911% 16,07% 8.21% 3,57% 72,14% 99,99% o aa 4,6 export to SW 2,0 To Copper Gulch 40.4 To Summer 0 & Spar G 56 otal Where it Dl'ains S ar Gulch Tributa Area Bar Gra h: 657 6 , otal of Parts otll II Lilll Com onent Parts Keno Gulch Tributa Area Bar Gra h: P.12 July 30, 1997 8,21% 3,57% 72,14% 99,99% 93,55% 502 I. c.... Com nent Parts Leonard Rice Consultinll Water Engineers, Ine, ( Printed 31.Jul.97 ) 41.35% 50,80% File: Snow_RO.WB1 AUG 01 '97 11:'59F1M L R~ E: ,-, P.13 Aspen Skiing Company Preliminary July 30, 1997 Table 4 Hlstorleal Snow Coul'$e (Snowtel) Data for Aspen Mountain- Gage Named "Aspen" (a) Fer Compared with Water Equh,alent of New Snow Over Spar Gulch Basin Comparison, Averege Water Febl\laly 1 Report March 1 Rlport April 1 Rlport MIIY 1 Report Equivalent of Nft, Snow OYer Snow Water Snow Water Snow W.ter Snow Waler SpeI' Guloh vear Oate Depth EqUivalan Date Capth Equlvalan Cata, Oapth Equivalent Oata Oepth EQuivalent Balin I (lnehn) (Inohee) (InClh..) (Inch.s) (!nches) (Inches) (InClhes) (Inches) (Inch..) 1980 1.26 SO 8,3 2.25 59 17,4 3-25 71 19.6 4028 53 1S.3 0,44 1961 1.25 25 4,8 2.25 34 8,8 3-25 45 10,1 4026 46 15,6 0,44 1962 1.26 55 1S,7 2.25 8S 18,4 3-25 68 22,4 4028 ee 20.9 0,44 1963 1.28 24 4.1 2.23 34 7,5 3-30 38 10,6 4-24 34 10,5 0,44 1964 1.25 32 8,4 2.22 38 9,1 3-22 48 12.2 4-27 45 12,8 0,44 1965 1.28 51 14,5 2-28 as 18,5 3-29 95 25.1 4027 78 23,5 0,44 1966 1-28 35 9,4 2.25 41 1o.s 3-28 41 12,0 4-27 38 12,0 0,44 1967 1-29 44 10.0 2-27 57 17,5 3-29 49 18.e 4-28 45 18,1 0.44 1988 1.29 38 8,5 2.28 47 12.3 3-29 48 13,1 4-28 ee 2M 0,44 1969 1-28 84 12.5 2-28 52 16,4 3-29 58 1S,2 4027 42 18,0 0,44 1970 1.28 45 13,0 2.25 52 1S,8 3-29 61 18,0 4-28 72 26,7 0,44 1971 1.28 41 12,3 2.26 8.1 19,8 3-29 70 24,9 4-28 56 17,9 0,44 1972 1.28 44 12.3 H6 51 15,4 3-28 51 18,7 4-28 53 21,7 1).44 1973 1.28 41 11.4 2.28 42 12,2 3-27 54 11,7 4028 59 21,0 0,44 1974 1.28 51 13.4 2-25 54 15.7 3-29 39 19,9 4-28 80 24,7 0,44 1975 1-28 48 10,9 2-25 52 14.7 3-28 72 21.4 4-28 81 21,6 0,4<1' 1976 1.28 40 10,3 2-25 54 115.0 3-28 58 18,7 4-27 55 23.0 0,44 1977 1-27 20 2,3 2.25 30 U 3-29 45 12,0 4-28 24 a.5 0.44 1978 1-28 50 14,4 2.25 52 16,1 3-26 71 26,7 NS 0.44 1979 1-28 53 15,2 2.24 57 16,8 3-28 54 17,4 4-27 52 18.5 0.44 1980 1-27 35 8,1 2-26 56 14,0 3-26 58 18.4 4-28 53 19.0 0.44 1981 1.26 15 3,3 2-23 22 4,9 3-26 35 8,7 4-25 S1 10.4 0.4<1 1982 1.26 46 12,6 2-24 46 15.2 3-26 58 19,4 4-26 59 22.2 0,44 1983 1.24 28 6,6 2-23 38 a.a 3-25 58 19,4 4025 58 18.4 0,44, 1964 Gaae Oisccntinued IlIverage 39,6 U 47,9 13.4 56,4 17,6 52.3 18,2 Maximum 64 15,2 63 19,8 95 2e.7 76 28,7 Minimum 15 2,3 22 4.9 35 6.7 24 U Avg '83-'77 Avg '80.'77 41 40 10,1 9,9 48 49 13,7 13,7 55 58 17,3 17,3 52 53 18,4 18.3 (a) SCS Gage "Aspen" -. Colorado River Basin (Roaring Fork) Gage No, 061<22, Lal39 Deg 9 Min. Long 108 Oeg 49 Min. Located on Aspen Mountain at Ski Lift Number 3. See 7, T11 S, R84W, elevation 9,700 feet, Leonard Riee Consulting Water Engineer\!, Inc:. (Printed 31.Jul-97) File: Sncw_RQ,WB1 AUG 01 '97 11:S9AM L R~ E ~ P,14 Aspen Skiing Company I"rellminary July 30. 1997 Tlble 15 I Hlatorlcal Snow Course (Snowtel) Cata for Aspen Mountain- Gage Nama "Lift" (a) For Compared with Water Equivalent of New Snow Over Spar Gulch Basin Comparison. Average Walar February 1 Report March 1 RepOrt April 1 Raport May 1 Report EquiYllant of NlIW Snow Over Snow WafM Snow w.tar Snow Water Snow Water Spar Gulch vear Data Depth equivalent Date Depth EquiYalem Oate Ctpth Equivalent Date Ctpth Equivalam Basin (Inchl.) (Incht.) (Inch"! (Inchl.) (Inch..) (Inches) (Inc....) Qnahlls) (Inchell) . llla7 2-01 63 17,9 3-01 8S 21,8 4-01 78 28,4 0,44 ,1958 2-28 56 13,3 3-31 64 16,8 0,44 1959 2.01 31 6,' 2-26 45 10,5 3-26 45 13,5 0,44 1960 1.26 28 7,6 2.25 41 10,2 3-25 53 15,6 4-26 35 10,8 0.44 1981 1.27 32 8,' 2-23 50 10,6 3-27 57 16.6 4-27 82 19,1 0.44 1982 1-27 68 15.8 2.23 82 21,0 3-28 81 30,3 4-23 83 28,3 0.44 1963 1.28 21 2,9 :lo23 34 6,4 3.30 40 10,8 4.24 3S 12,2 0,44 ' 1954 1.25 33 7,3 2.22 39 8,8 3-22 57 16,8 4.27 50 18,2 0,44 1985 1.28 53 18,9 2-28 58 19,9 3-29 103 29,9 4-27 80 28,0 0,44 19S8 1.28 34 9,2 2.25 40 11,3 3-28 43 12.9 4.27 38 11,4 0.44 1987 1.29 43 10,9 2.27 59 16.0 3-29 50 19,3 4-28 53 18,2 0,44 1968 1.29 34 B.5 2/28 45 12.4 3129 47 14,3 4128 68 22,3 0,44 1989 1.28 58 12,7 2/28 49 17,0 3/29 54 18,1 4127 43 16,4 0,44 1970 1.28 43 12,9 2/2S 53 15,2 3/29 63 17,5 4128 70 24,9 0,44 1911 1/28 42 12.0 2/28 58 15;3 3/29 es 20,7 4128 81 21,2 0.44 1972 1/28 42 11.0 2/28 50 13.9 3/28 49 14.4 4128 50 17,7 0.44 1973 1/28 38 10,2 2/26 42 10,8 3/27 55 17,0 4/28 82 22,2 0.44 1974 1/28 44 12,8 2/25 47 13,7 3/29 48 16.0 4138 45 17,0 0,4.4 1975 1/28 40 10,1 2/25 46 13,3 3/28 81 28,3 4128 80 20.2 0,44 1978 1/28 34 10.3 2/25 43 14,5 3128 52 '17,0 4/27 46 19,3 0,44 \11977 1/27 23 3,5 2/25 30 5,0 3/29 39 10,2 4128 30 9,7 0.44 1978 1/28 52 15,1 2125 50 15,93/28 59 20,4 NS 0,44 1979 1/28 42 12,3 2/24 48 13,6 3/28 74 21,7 4127 56 22,2 0,44 1980 1/27 43 11,3 2126 68 17.8 3/28 69 23,0 4128 58 23,8 0,44 1981 1/28 24 5.4 2/23 29 a,s 3126 46 12,4 4125 38 14,8 0.44 1982 1/28 54 21.8 2/24 56 19,0 3126 68 23.6 4/28 !l4 28,2 0.44 1983 1/24 33 8,8 2123 48 12.8 3/25 71 20,4 4/25 85 23,0 0.44 1984 1/25 55 19,6 2124 68 23,2 3/24 82 29.8 4/26 87 33,0 0,44 1985 1/25 48 15,4 2/23 82 18,S 3/23 88 21,6 4124 67 22.8 0.44 Averagll 41.3 11,3 50,4 14,2 80,0 19,1 5/1,3 20,0 Maximum 88,0 21,8 82,0 23,2 103.0 3Q.3 87,0 33,0 Minimum 21,0 2.9 29,0 5,0 39.0 10,2 30.0 9,1 Avg '83-'77 AV9 '57.'77 39 40 10,1 10.3 46 49 13,0 13,5 55 51 17,4 18,1 53 ' 54 18,8 8.8 (a> SCS Gage 'Lilt" - Colorado River Basin (Roaring Fork) Glge No, oeK27 Lat 39 Deg 11 Min. Lon9 10e Deg 51 Mill, L.ocallld OJ'! AsplIn Mountain at east of Sundecll, Seo 7, f11S. ~84W, alllvsllon 11,250 feet. Leonard ~ice Co"auKillg Water Engineers. Ino. ( Printed 31.Jul-97 > File: Snow_RO.wS1 AUG 01 '97 12:00PM L R~ E ,.-., P,15 Aapen Skiing company Preliminary July 30, 1997 Table 8 Water ~quiv.l.nt of New Snow Sp....d 0\1., the Major Tributary BIIlns Area of Water Wiler Total New Snow EqUivlllent Equivalent Description of Beein Tributary Inoluded in New Snow Over Conclusion Arel Thll e.sin In This Buin 'MIole Basin (Acres) (Acr8I) (a) (Acflt) (Inehe.) Spar, Copper and Vallejo Gulches 857 42.4 24.03 0,44 Not Significant Keno Gulch, including import from Spar Gulch via Summer Ditch 502 40,4 22,89 0,55 Not Significant 31,73 Water Equivalent of 56 Acres of New Snow Area After 6% Spray Loss, (a) In the eaM of the Spar-CopperNallejo Gulch analysis, the Summer DitGh is not considered. so 42,4 acres of new snow lIrell contribute to the whole Spar Gulch basin, as does the entire am tributary to the Summer Ditch, Leonard Rice Consulting Water Engineers, Ine, (Printed 31.,JUI.97) File: Snow_RO.wB1 AUG 01 '97 12:00PM L ~,W E ~, P,16 Aspen Skiing Company Prellminel'Y August 1, 1997 Table 7 Average Rates of Flow'for Melting of "New" Snow 40,4 Acl'llll .8 11.54 5,77 3,85 1.65 0.82 0,38 0,26 7,52 23,07 11.63 6,81 3.88 HI6 0,83 0.39 0,26 11,27 34.60 17,44 8,72 5,81 2.49 1.25 0,58 0.39 3.88 11,90 8.00 3,00 2,00 0.88 0,43 0,20 0.13 42,4 Aores 7, 4,0 12,11 6,06 4,04 1.73 0,81 0.40 0,21 7,89 24,21 12.20 El,10 4,07 1.74 0,87 0,41 0,27 11.83 3el,31 18,31 9,15 el,10 2.62 1.31 0,61 0,41 4,07 12,49 6.29 3,15 2,10 0.90 0.45 0,21 0,14 (I) After 6% spray 1088, (b) In the Olse of the Spar.Copper.Vallejo Gulch analysis, the Summer Ditch is not considerecl. so 42,4 acres of new snow area CO!1tribute to the whole Spar Gulch basin, as does the entire area tributaly to the Summer eitch, Leonard Rice Consulting Water engineers, Inc. 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I 1 '----' l;l '13 I I", l~ Q F, I I I " i I i C") .... = c::i ~ c::i I -L , i iIi l! CI) C ~ '"") >oS - 8 f CUC c:i ~~ E I It - I , I I I ltl: CD, ('I' d\ I I I I I I , , , , , , , I , I , , 1 " , 1 r , I I I It) = It) = ~ C N N .... .... C c::i . d c::i d = (;) 8.:10 eBeJeNv 'C Co -<: rJ = - ur I I I i ~ s j '5 - = ~~ 101 ICE ~~ 1- as I~ ~ I J:l ;;00 i._ II) !Q Z I .. i ! CD CI) ! E >- ! e ~ ia ; II Q ~ . WI E \~~ == a: (;) ~ (;) i .. .. .., t ... I i I AUG 01 '97 12: 13PM L R eWE ~ ,""" P,8 i J f n I ~ I IF! L-.-J .~ 11 ~CI.l 8:1 o ... I(J m Q> ..... Q) 11 ; :so! a= E e lo;; co ... c d ..... 8 d ~ :s ..., r Iil ~i 0 .s:::. - 8 fU'c ~ d :20 :I: <l= ... Cl j I .. it -I- - It) ... o c:i "'it ..... o c:i i N ... C! Cl I I I , I , I I I E g ~ c:i c:i Cl s:!o e6BJ8AV - .- "- ~ g I 8 s 8 j 0 Cl l!l d c:i c:i J B IX ) AUG 01 '97 12: 13PM L R eWE ,'-"'. BACKUP DATA .-, P,9 Leonard Rice Consulting Water Engineers, Inc. AUG 1211 '97 12: 14PM L R ~ E , ' ...-., P,ll21 Aspen Skiing Company Preliminary August 1, 1997 This Notebook Created by Leslie H. BotIIam, of Leonai'd Rice Conaulting Water Engineers, Ine. 303: 4!lS . 9689 Purpose: Quantify Impact of Naw Snowmakingon Aspen Mt ASSUMPTIONS FOR THIS QUATTRO 5,0 FO~ WINDOWS NOTEBOOK: Fill: SnowJ~O.WB1 30-Jui-97 l.nt Update Plowratts and Volum..: 1.9836 Acre FeetperCFS_Day 449 Gallons per Minute per CFS 7,48 Gallons per Cubic Foot 325,860 Gallons per Acre Foot O,84e272 Million Gallons per Day (MGD) per CFS Time: 1,440 Minutes per Cay 88,400 Seconds per Day Lengths and Amll: 840 Acru per Square Miie 5,280 Feet per Mile 43,560 Square Feet per Acre Mlso.laneoul: 3,21 Feet of Water per Found I Sqare Inch (PSI) 82,4 Pounds per Cubio Foot of Water @ eo Deg F 32,2 Gravitational Acceleration Constant 2 Rounding Constant Specific to this workbook: 01-Nov Firat day for restaurant's water use 31-Jan Ullt day for restaurant's water use 30,000 Gallons used for restaurant use every 0 days, 180 Acres of existing snowmaking area' 56 Acres of new snowmaking area 1 0 Days per O-glllon water-use block of time for restaurant. 11 Million gallons per year for new snowmaking area 8% Spray LOllS Leonard Rice Consulting Water Engineers, Ino, ( Printed 01-Aug-97 ) File: Snow_RO.wS1 I I I I I ~Cj(:;"I11~~ ,?'" -, " ""~ .' ~1' '. ~;Z,."....=,~-1-::~11."- ~,~: c_~"...., CITY ASIlIEN. OF ASPEN CQLCRADQ , , " " " /~ URBAN RUNDFF. MANAGEMENT .,.'PLAN etftrtn'c.~: C6P'J ING1N15!,'R1NQ DEPT. CITY OF ASPEN, BOX V ASFEHCOI,.Q.,SliU/ WAIGHT-M=I-AU13HLIN .NGINIliEiAS I!NClINIlERING CCN*UL.TANTS CENVER, cell.CRACC AUGUST, 1873 ? 2.1 , , 'I I I I , I I i i " 1 i i ,! , , J HUG 01 '97 12: 16PM L R eWE 1""", :~ P,12 0),', ,..... , , ,.', ," ASPEIl HOUNTJ\lN LODGE, 700 SOUTH GALENA STREET, TOP OF 111LL MID UTE CITY PLACE STORt,! \lATER ORAIIIME REPORT /"~ '\ (:. ',',' PREPARED BY REA, CJ\S.SENS AND rlSSOCIATES, INC. CONSUl. TING ENGINEERS 4388 SOUTH W!NIlEP.l1ERE STReeT ENGLE\oIOOO, COLORAOO 80110 789~41\28 1-800~332~9&96 201 N. HILL ST. SUITE 207 JEROME PRUFESSIOHAL BUILOIMG ASPEN, COLORADO 81611 925-~799 January, 1985, . '.... l~~~ : ~<:,.; i , , , : - L:l " ,r, o , ~ . '.',,' : ',,~:.' ".. ' . ....... . .i.{":\,.:,:. . . . ; ';'.:.....,:: . ,'..:..r:.....;.., ".-..'.,'J." 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'.... \ "'", \ :-\ , I ."\~li'! \ 'I, ~J,r j 1'\ ". \..~.\_~',:'~ ",' ''',,: \ 1 "101 " ....;"l "I,L.,' '. , '... _, \ III ," '\ l . I'~ . ~ ,-.. <or. ''t/l....'. \" ,_ \ ,"-. ,"t, o " ... "J ! 'I.L- ' '" 4' ., .~ _J;I~ '\ \~ "\ "\ \ '. ~'I 'd, " -... I ~ \, """ \ ',\ \ \ " ! ,4.1J \; ". ,.......\ '\ ~~. \ \ , ~l",~ ; \ I, \ \~, ') , ! I. \-. \ ' )) ,I ~ ' . i ') ~) ) / (...,i. ,'j "s)AR GUL.;C iJ. .fL., : OlTCH\ OJv.! $iOf!f", ':: ) , \"\'- "\"" ,WI/ aet! ' }'. -) t ., :i \ MOun taln ( J . [~ . " . ." 0;" ..., ,~ I" ,... ....J f I , , I -I :/ -' .' .- ..... .' , , ~ '..~, '~I ,.0, . 0/. , I, I \ . ) . , .' . ... 11;./ I $' ~...~ r~~ --'- . APPROXIMATE BOUijt)ARY ..J..,' t , I I" \ '.' ,~ OF LANOSI.IOE AReA " :, . .' " '\ ...~ ,.,...., , . , .. 'i, I \ ." v' I ,":. \ " ~ _.. \ ' ' \ ", ", I , '. . '\r- I.. , " -, \~ . F. "" R r \~ \ I \ ',", . \ 110 " Tourt"Ucue\\" ,..,~ I \ " I ", \ " ~; , .. w T I H i',\:\.; .~. Q,,~ ' .. I.',,". WRIGHT WATER ENGINEERS. INC. ~490 W, ::!6"~1 AVE, 100A DENV!R. co 80211 (.30.3)480,..1700 DRAWN DSlS CHICK .JVVR OAT! 119& SCALI" .--zOOO' FIGlJRE 1 INDEX MAP ASPEN MUSIC SCHOOL DEBRIS FLOW 811.oe2,OOO .;;,t:4 ~'~, r ,;;...\l ~t:.:;,::::,,~ '$S i.~t 'i...;'L-..c, .. ;,'!; , -"~~:'::O; .1""'\ 15" SCARP STABLE IN MORNING WET AND RAVELUNG IN AFTERNOON- CUT SL~PE1 ~ I I ( \. ORIG, STABLE GROUND HEAD SCARP WITH LOOSE COVER, CLEARED OUT AREI TIMBER :HANNEL THI M ENOOf~'I'I C*NNEI.,-p; ~ SI.OI'E11" ~ ...~NEI. , C~N C""", RUNNING S;:ROCI'- TREE DEBRIS ROAD ON STABLE BEDROCK ~ BEDROCK HEAD SCARP \: 39' SLOPE ~ ~ !O'WIDE I'DEEP 10 .. OLD ROAD 46' ORIGIN SLOPE TO I NOTES: WHERE AS FIELD ESTIMATES WERE HORIZONTAL MEASUREMENTS, THE EASToV SKETCH MAY BE DISTORTED AND MAY BE 2 OVERALL TREND OF CHANNEL HEADISCARI OVERALL SLOPE OF CHANNEL HEADlSCAR'oLD MADE MAY 17,1996 AFTER THE DEBRIS FLOW 1 AND 14. ;WM: WIlIGHT WATER E FIGURE' . . .2490 W. 26TH AV~. SOURCE OF KENO GULCH DEBRIS FLOW . DENVER, CO 8021pEN MUSIC SCHOOL DEBRIS FLOW ' (303)480-1700 961-062.000 11 ~ 3 D U .I .J 1 1 1 1 1 1 1 1 1: ., =I .-::;iI ~':I 1 .1 AUG 01 '97 12:22PM L R H E /"""",-, P,16 lmM..~ttrtitUf ArJY!" Mwlir. ~lttJt'JI o./',.i!r P1ww and Alan Chleborad, landslide experts with the USGS; and others. There seems to be some differences in the various opinions as to the imminenco of the slide and the degree of danger from it Suffice it to say that the AMS personnel took tho wamlng seriously and went on the alert. Bill Savage and Alan ChIeborad (personal communication May 29, 1996) estimated the volume of the landslide as 70,000 cubic meters. Field evidence indicates only ono-third to one-half of the material hac1 releasod as of May 17, 1996. Mr. Blanning (personal communication May 26,1996) set seme monitoring stations on the head ICl1lp of the slide and said he neted movements of two feet, four foet, and eight feet on sucbessive days (apparently Friday, Satl1rday, and Sunday) leading up to the Monday event. On May 14, Tuesday, after tho Monday event but before the Tuesday afternoon event, many of the people revisited the site, and Art Mears and Jeff Hynes inspoctlld the slide and the, channol do'Wn to the AMS campus. On May 17. Robin VerSchnoider and John Rold visited the slide and spent most of the day mapping, photographing and evaluating it (Figure 3). The landslide represents a typical example .of an alpine landslide which became a debris tlow, The rapid snow melt infiltrated the landslide initiating slew movement, cracking. and bulain& for several days. The Clacks and d.ilation 1I1l0wed additional water to Mther satu:lte the slide totlte point where it mobilized as a very fluid debris flow. On the 300 slope, it qllictcly would have attainod a high velocity with considerable erosive Power, When it reaohed the confluence with the Spar Gulch drainage diVllrSion. the additio~ water provided greater fluidity. Art Mears and Jeff Hynes, who visited the ~te Tuesday afternoon between the two events, each separately related to WWE thoir hypothesis of the conversion of the landslide to a debrii flow. Wl'i,ht Wat'" En,in./II'IIJDhn W. Rold 1'tlgr/11 { . ] -Il j] :] -ll Jl -!1 ...iI ,~ '~ ':U I) ..~ -~a -U -1 1) 11 1 '-11 'fj RUG 01 '97 12:23PM L p~ E ,..-." P,17 lJ11\U1"ifP/iDPI AJ""nMu,it!~~hf1nl I)"AriJ Flww Each felt that the landslide had slowly oozed downhill to the junction of the Spar Gulch drainage channel where it plugied or dammed the channel. The additional water then mobilized the landslide, tuming it into the debris flow. They actually felt this might be beneficial overall becaUlle the channel water would mobilize small portions of the slide, a little at a time, as it moved down. This would release the ma.terial in small, sepamte surges, thereby avoiding a Iaracr, more catastrophic event. Based on a detailed she il'.spectiol1, WWE believes the field evidence (Figure 3} belies this interpretation and indicates that the landslide became a debris flow in essentially its original location and was a debris flow before it reached the Spar Gulch di....ersion cbllm1el. 1. Su.""ficient water would have been available from the rapid snowmelt to mobilize the landslide. Considerable snow would also have been incorporated into the la."ldslide and debris flow. 2. The narrow channel between the landslide site and the junction would more likely have been caused by the erosion from a debris flow than movement of a landslide mass, Mud spatters found on trees above the clwulel indicate a high velocity. 3. Ma.terials left in the channel indicate they were remnants of a debris flow, not a landslide mass, 4. Messrs. Mears and Hynes and others visited the site around noon Tuesday. The slide mass wu then 200 feet to 400 feet above the confluence ~th Spar Gulch. In the three to. four hours until the next event, the material would have to have moved at a rate of SO feet to 100 feet an hour to reach the junction, fonn a dam, and mobilize. At anywhere near that velocity, the material would have mobilized;, W,I,hl W"t" Engi,.,>'IIIJoItn IV. Rold 'flgtI /J , ill I ill ,u , -:-fij ~ ...,' l'~ . ~ JjJ : ,ll ,M' ~ -, r'i " lJ n '~ . ~ :'-n ~:'-1 "1 -'J] :1 ',1 '1 ,1' AUG <Ii '97 12:Z3PM L Rf"""'*l E 1""'" , P,18 lJ1ftM.fl~tifjll .J .~IIH MtL.,~ .~hNJl n.ltrl6 mow thick. Only a very few boulders larger than 18 inches Kross were noted either in the debris flow. deposit or the landslide material. CONCLUSIONS 1. The landslide and the debris flow y.>erc dominantly a natural event caused by rapid melt of an unusually high spring 1996 snowpack (139 percent of the 20.year average). 2. Field evidence indicates that the landslide had mobilized into ~ debris flow before it reached the confluence with the Spar Oulch diversion channel. Therefore. although the Spar Gulch diversion water may have increased the fluidity of the material. it was not the cause of the landslide, or debris flow. , 3. The occurrence, magnitude, and behavior of the two debris flow events dift'er little from predictions Art Mears made in 1989 and 1993. 4. Under the adverse conditions that existed, staff of the AMS made a reasonable emergency response to the event. S. The old mine accesa road above the landslide head scarp may have exacerbated the problem by conc:entrating drai~ge into the landslide ma. Material removed from the road cut above the slide may have been dumped over the side and may bve exacerbated the landslide process. , . 6. Approximately one.half to two-thirds of the landslide mass remains uphill in Keno Gulch. Another spring of rapid melt of a laraer-than.averqe snowpack or an intense or prolonged ' thunderstorm event could triiller additional debris flows ,similar to, or even somewhat larger W~lght Wmllr Engl_r8lJohn W, Rold Par'U AUG 01 '97 12:24PM L R~ E Alpen Skiing Company Leonard Rice COn&Ulting Water Engineers, Ine, ( Printed 31.Jul.97 ) ,......" P,19 July 31,1997 r1lf File: Alpen,WB1 AUG 1211 '97 12:24PM L R~ E t""'\ P.2121 z I(~j ~ ~ ~ &I .il ~I nl a~ E!~~ i =M~ Q(f).,... ~ I I; ;~Ie fD cieri... ~ .. '&I I il ; . . : )0- f 1 ; II ==~ ~~1l co'" .... ii '-' o":d q> "5 ~J "" .a! 7 ~ II! - ,., 16 ~ II II! II '" """,II) <ol:"!~ ,2' ~ u ' ,,., d ~lD<<:i ......""a:i - 1I N l: 2~l ~ en In 2 '! m ILl i ~ "" ~ ~ i! ~ s ffi I I' m ~ a: ~~ll;l ~ i If CllCllln aicDlri J '-' a: II ~ I ] t I ::l ~ I ! 1 w ! C.) Ii ! 1 0: ~ ,Ii li 0 'I ~ I I l P.2 AUG 01 '97 12:32PM L R~W E i-.". Jr* 1C ==: - ffi Ii) t <Ii - ~ ,i e u.. ) ~.~ l il I!! mil. I Ii I ~ - <l> ~ Q ""! .. i~1 - GO CIl , , '!! ~ iii! I I ) z !~:e m'l dedI!! ~ <Ii ...0 ,5 ~!= II .. ~ ")0 11 ii !c ! g II = '7 ;;; R - "'-'" ... i Ii cS~~ "'- ~Ifi ,.;lL. = II I~ =5 t i~ i a:: "! .. Ii ~ ! lUu .e l.: ~Q!~ .! I j 2-l 8 ....I,l')GCS I ~ II II !'Cc.... .;lo I J )i-O~ c ;;;- wi~i .r/! !j 2ill~ it ~i ; w g Ii a:: i t Ii Ii ed , . 'C I!~ I s. i ll;;~ ~.! 5 hij ~I 'J i ==ui ~ I, ~ <t1 JJ iE ia:: ! c ~ .. ii I I!~J I .. J ~ >'11 f ~o III I ~i 8 i I I- 12:32P~1 L R K E '" ii'in' lIIi.. 888888~~tiIl I~i ddddddulC;>C;> ga- I Iii ~~!~~~;~~ hi ! il:~ ~~~~~~.~~ ~ ~ ....====~N... _ S t- . ii II ~ - lit ~ ~~~~~.~~~~ a_= ....__....__......_ oi<=- 2;=: a:! ,..~ .. AUG 01 '97 ;11... iii J I il J I ~;;!.~ d I'r illl J ~ ! i !~ I ili ! -d:!i~ ~5 ~"i i ,-" P,3 'If" S88888~~~ =c::i=c:i=dS!c:i~ ~~~~:Hi~I~~ ...-------- 00.0000000 ...!NNNNcoiNNN ,...........-.......,...,.. g~~~mi~i~ j i .i '" Sl -5 7 .. '" ~ ~ ~ ; w ~ (!) i ~ ! "" .. . -' .. , ,.... , ,4 .: r-i .~\".'~'." ,~\7':~-:' " ,,:~;~!:< THE COLORADO SKI COUNTRY USA .. ~ '," ,....."" .....,..~ '''WAT~ MANAGEM~NT RESEARCH 'PROJECT .~ ~~.'~~!::'.. .... , ~~~~::". '~\\li,,:' , HANDBOOK " ......,..~~f". . .'. . !.."J~;:t1'~.~ . ," oi,#j~!f:' ~.:,. " , .,\ l:::!'" ~: .. . ."~,;;;,;a;;,;.;..'.. ~;~r...t~ : " ,'M~~!:~:':, " . !~:}.:.:!.~.. '!"'. ~: .~ ~i'L" ~~, FEBRUARY 1986 ," ,." S~SiUjC1:i FIGURE 2 'tmr<f!f REI..AT10NSHIP 8ETWEEN PRECIPITATION ANO EVAPOTRANSPIRATION OURING THE WINTER SEASON AT eOI,.ORAOO SKI AREAS (Reproduced trom F lI;ur. IU -24, -An Approach to Water "..our~es Evaluation of Non-Point SilViculturel Sourc.." Troendle Clnd I,.laf, 1980 l RELATIONSHIP SETWEEN PRECIPITATION ANO EVAPOTRANSPIRATION OURING THE S~G SEASON AT COI,.ORAOO $1<1 AREA S (Reproduced from Fi9ure III-aS, "An Approach to Wet.r Resource. Evaluation of Non-Point SilvlculturClI Sources" Troendl. and L.eaf, 1980) SOUTIo! ~UG 01 '97 ; .. II en ~ Co.l 3 10 . ~ l- e a: 5 a:: en 4 ~ a: 3 l- f ~ 2 101 ~ 1.2 ~ 0 e \Ij en , II: III II' III II II \ I II .. CIl lIol ... i 10 ... . ! ~ !Ii ll; z I l- f J \Ij ! 2 11.1 0 c \H I ..' 12'33PM L R C W r /""""" -33- Let I 4 Iii 8 10 12 SEASONAL PRECIPITATION, INCHES lEi 14 ,FIGURE 3 q. I 4 . 8 10 SEASONAL. PRECIPITATION. INCHES 14 16 -'." ~~G 131 '97 f ,. I' , I: I I I I . , I ! I ~ -. 12:34PM L R C w l ,1""\ - P,6 11 -35- ,"""" .smd~;oj FIGURE 4 FlEL.ATIONSHIP BETWEEN PRECIPiTATION ANC EVAPOTRANSPIRATION CURING THE SUMMER AND FAL.L. SEASON AT eOL-ORAOO SKI AREAS (Repro ced fram Figure 111-26, "An 'Approach to Water Rucur 8S Evaluation of Non-Point Silviculturol Sources" Troendle and L.eaf I 1980' 10 "I VI eI I.l.I "7 :: ~ <:,;l 5 ! . 4 ..I! 3 I~ III - 2 ell. \Will IIlz I ... I.a f 0 ~ loW i ~ i AL.L. ASPECT 5. I I } 2 16 4 6 a 10 SEASONAl.. PRECIPITATION, INCHES 12 14 !U~ 01 ~7 12'34F'M L R .K l:. ,~ I, I I I I I I I I I I I I I I I . . . -37- FIGURE e. RELATIONSHIP BEiWEEN FOREST COVER DENSITY (Cel) ANO EVAPOTRANSPIRATION MODIFIER COEFFICIENT (m) 1.3 - a - I- ' z l.Z !j Si "- II. ~ 1.1 (.l lI: \&j iO: 1.0 - Q i z .9 Q - ~ < Q: E: .8 en z ~ .... .7 c Q, ~ \&j .6 1.4 .5 ,. o CltmQJ,/2 FOJltE5T COVER OENSITY (CeI) NOTE' FOR EAST-WEST ,t,SPECrs INTEAPOI.AT! Ie:TWUN THE NOATH-SOUTH L.IN!!. C4mall . P.? , I II -- II II . I " ". II ~ AUG01 '97 12:35PMLRCWE: .",-" ..'..,..." -,-........ P8 ~ .31. ~~ RlCAT10NSNIP 8ETWEE~I'~~~;SE~ l\lAPOTRANSPIRATION ~ AND QUANTITY OF MAN-MADE SNOW FOR AVERAGE, WET AND ORY YEARS e !i - II - - ~ I- ~ 4 ! a:: VI Z l- e VI = VI l- S ~ 3 Q > ~ \l,j VI ~ 0: IIol I l- ~ J Q 2 too t - I .2 1&1 z 1.25 - OFlY YR, ,.., ~ < .'f-",..~ ,"'~~,:L~::i"'::;. ..:.';! WET YR, (c,B 10 15 20 as WATER aOU1VAI.ENT OF MAN-MACE SNOW(in,) I I I I I . I I I . I I I I i I I I . AUG 101 '97 12:35PM L RK E .43. Table 1 CRITERIA TABLE ,-, P.9 Guide to r.f.renct tabl.s for us. in distributing the change of runoff and evopotranspiration due to .no"moking over the time period October 1 to June '30 Average Annual precipi tat ion ( inChes) l.oootion )35 Wat and East Slope. East Slope West Slope ~O.. 35 '30- 35 '30 Eaat Slope Use Reference Table for Snowmas. -( Table' e ) l..ake Eldora-tTeble. '3) Winter Parlt-{T(lble-7) or Voil"{Table" S) (Use the one clesest to yellr area) Conqullltador -(Table-a) , ' , '.... ..,_.."'WW..,.,."""._""'-:'.......'_iji~ti-.:..~..-l"....':' '''' 'j."'" '-~-~":O," ,"",'... -" '-, ,. , '...,' ,~~.. ,......"",.,....', '-"."""'"'''''' '..,...,:".,_..,:"...._,.."" :.:-:."', ..,/ . . AUG 01 '97 12:36PM L, R~ ~ ..~;- "......" P.10 , I ~ . c.. 0 - G'" t.. e e = c = C '" - .. z :i2 GI Or... ~ .. , = >- cr:: I I ~~!c.'l= e e = = = = .. ... .. 1lI>'"_ CI'I tl:j2V,l4>_ I Zr .= = ... 'i' i:o. '1= = = = = = = "" .. e ,., ...... II> Cl>_ . cr:: tI: I ell 0 g Ill'" 'I- e e = e = = ~ <0 "" . - ~ -'" .11I11>_ =1 ' ~ c..1II o .. II, I e = "" = POgO', 0 = c = .. . - . - Po I-_V,l>"; == Z.w <>_ = ~Uol'" - ~ g l:l': . Po ~ ~.. 'I- e e e = '=' <:I .... "" = In =.. =-..... CI'I ..- I SC>- Q I tI::.l "';:1 =,- f"- 1"1 Iii 0 <l- N N t"l '" .. .... III "1..:1 ... .... .... .... =11>- llIi - .' ~ .III ~ e -I. M ... - ii!1I'1;lo .1_ t) CI.l .... <::0 '" <.III "' It) "" ... ... cr:: Zz .. c > "lll"l ... N .... .. rl:<>-- . CI.l ;:'0 _Uol > ..l \- .w~ - -Po V,l... rJ: -< 51> '\- e .. .. '" "" "" ~ 2 .. . -cr:: "'..... - N ,.. "-l_ Q>- ll\lQ,. OV,l I b~ 0= .. '1- .... ,.. ,.. '" ... ... lIS ... .. P- 41,"... ... ... ... ~~ 11>_ .s i . 1-< .III I, z> -I, I I ~w c ';!Cl._ N = = c = .., ... II'l :e .. :1>...... .. .... ... , ~ ....1:<>-- ~ I V,l a. ... .III.. fI.li ; t :: > "\- e - c e = c .... ltl N I I .......... .... ... 1"1 I sc>_ , I , I ~ , . . . , ! I j , . ! ~ ~ I: .= .. a .. I ~ :i :i :l , l\I ,/ Z '"' '" .... I I ! I J 1 '97 1 :36PM L R Summa.ry of Snow Survey Measurements Colorado and New Mexico II ;/r!. j; <:.. 7'('- Ot:r 1971 - 1977 ';"1', ;::,,~~:~):y~~,~~?;;~;.~?j~}5.-it;;~ "." -.' . Fedel'lll ---- State ---- Private Cooperative Snow Surveys U.S. Department of Agriculture Soil Conservotiol'l'Service -...-............. RUG 101'97 12:37PM L R ,,K E Ii .... .... <'l ~ ~ ! I i f i , ' 1 ! i<' I I' Ii! \ IW i I '.c 1:1 C.) (J)i == 2:1 ~c 81 I'" I i CI) :lE! i E 01 ! E &"1 = ~i U) ~I 'I- . oEt ~ -al .- ..... C.) 'E ca .- Q...J i~ ~ I ~ I I I I I I I I I I I I I I I I ! I ffi (.): ~I <CI ... I "I J .5 i en .. ~ ~I .~ I~ 1(1") I t I I 10 ,10 eN , I I I I 10 ... " ~ \ : \ : I \\ ~! ~ , g '~1 \ '! :11 !\ 1.Ela. ! , \ I l]j : \ I i = 1 =.5 : 1" ~+~- : !; "-INCO :' + -:-- -0- -.J1:~ a; : i\: ~! 1a , i \! csT's ffl \ ! i '0 (.)1 ~: .1 O.c: 10 . , , '-q_ "":.' I .... Q. n i ,! i (1) II \ i C ~ 1\ I ~I:\ + -I : - ' E' , i .e :' ~; t : 10 I ' 10 I . 10 00 I I I , , , ! o .... S.::l~ 'e6JeLjos!o P,12 , , I~ Ic ,- iE i~ I- i>;- Il.O I I I i I 1 ! '~ Ie IC ,- ie IS lCf.) ''- ')- , , IN I . : i , , I I 'a. 1:1 ;u 1- ,. ICO I'" I .... 10 ~ .~ IS 1+ i i !I ~ - ~ , :;; -;> .... <'l I .. a. - ~ l!f Gl 2! 't w j ell c - ! o (.) Gl ,Ii a=: '2 ~ AUG 01 '97 12:38PM L R~ E Aspen Skiln; Company Table A Capacity of Summer Ditch Ael.imited by 1tlI18" CMP Headwater to Cia meter Depth at Estimated Ratio Inlet Discharge HWID (Feet) (CFS) 0,5 0.15 1,8 0,6 0,90 2,5 0.7 1.05 3.3 ' 0,8 1.20 4,1 1,0 1.50 5.9 1,5 2,25 9.0 2,0 3,00 11,2 . Assumptions: Inlet Control Projecting Inlet 18 Inches, Size of CMP Culvert Leonai'd Rice ConSUlting Water Engineel'l, lnc, ( Printed 31.Jul.91 ) ~ 7 7 7 1 1 1 7 11 17 17 17 17 17 17 121 121 121 121 121 121 121 P.13 July 30, 1997 File: 'SnowJ:tO.WB1 -\ . . , I , 'I I , . , ~ T 54 "', '" > .. .. U ... o '" '" .. ~ .. 16 It .. Q " . Q ~ " ( VI '" " .. ! J 110 I" 15' 144 In .. oj .. ~ .' 'Ii 110 10' 9& .. I " ~ !l l! VI 10,000 8.000 &,000 5,000 4,000 3,000 EXAMPLIi I. J. InCMlll.O ft.1t 0,1...,11 y' .w u.,t) 1.4 G,S G,G 84 72 &0 '" I:l '" oil =, .........g 4a /" 6 / 36 48 3. 3D a7 a4 ---__ .I I. II 1,000 III (II ell ..a ." I.' .0 ill f"t 1,000 100 &00 500 400 300 If .. ii! aoo s -----,--- 1.0 CHART 5 (I) 8. (2) &. (3) / /' / /... /' ",.- -,V , Jl 4 /e ."i.// / VI p~/,/. III ;/ /,' //lii 100 /" 1 i ,,:Z ......... " // / :: 10 1/, Q , I . Z 60//,. ; 50 ' /' .. / . ~ L I!- 40./// .... ,/ .../,/ . ".Q 30 ,n''SCAl:.t ENTRANCE,', ,1: / lY / TYPf!:',/ ~ .~'c 1'/ /,[;, Mt~".'Ji~:'-"'''''' iI I ,~ ~ . ... Q . / /'" (I) ../Uifi"'" t, oolt10rlft ~ l /' /' ,,/....,..... to tlo.. :. /~ ," ti~~""'~ PrD,utin, ~ ,I. .,~J ~ >>" ',/ 8 "fl~ ,......-- "/':,/ ~ . /:'// ,c'll/ .' ..,-"'" ..,.,." .. / ~ ~', ......... l</ ,:;.;:,: ~ ",,,",' . 11 u.. ".1" (110 .r'{3(.'.Jlct 21 4~/;:'- ".,-' '-4 ..... " ".,11_atil'l; t. UOl, IU, th,,, 6s ,;.' "'.", ........" .. ,." '" ~'fQltht il'lcli/l.i Ihl' '"'IIIIt''' {/ .... .....:; .--"" 3 Oil" Q I.lal."t Ot "eftr" VI ~.:..~........ :..:....-_ __--ifttIlItrwrf'll:-----..---- 5. 3, I. ::..1.....- 1,5 1,0 ,I ,7 .S s. 6, ., 4, 4, 3. 3. 2, 1,5 1.0 1,0 ,9 ,a ,8 ,7 .1 .8 ,& .5 .5 HEADWATER DEPTH FOR C. M. PIPE CUL.VERTS WITH INL.ET CONTROL. 8URt;AU QF' PUBLIC ROADS ...."" 111$:1 ,-as K 1"""-, Aspen ,~, 199 Mountain 7 Master Plan .,," ;;i. '-r,- .. '...'- ......"'!" iI' ". " '.:'1''''' .......'. ~. ~.'. ...,~ '" ,,-lI' " . .~i---.fl-."""'w~.,. -, ~~,..-~.,..... '~'f" .'lII':::,~. I' . ~.~'" ....;f.. I' ..~.._...I. .,.', A u g U 5 t 1, 19 9 7 Tapa of Sundeck Area(Attached) Photo of Aspen Mountain circa 1958 courtesy of Apen Historical Society f""", .~. 1 9 9 7 A spen Mountain Master Plan ,.I'.:~'" ~ oW' . ;.. .; , " ,.~~..:-;' ~ ~:,,..., :~. .//".-)>,,,: ......". w '.~I' I*,.',..rw.;" .;:... ,." ;... .....""-.It,'~..~~":.;::.~."'t'. ~... .~.' R. _ .......~ ,..... ", ....... "'::.':--. ",r. ,#" 7f ,,'" ".. A u g u s t 1, 19 9 7 Sundeck Facility and Operations Photo of Aspen Mountain circa 1958 courtesy of Apen Historical Society ('\ i~i Aspen Skiing Company PLlI11llllg & Dc\ clOpl11Cllt Memo To: Brent Gardner-Smith, Planner for Community Affairs From: Bill Kane, Vice President, Planning and Development Date: 08/01/97 Re: Sundeck Facility Building Program and Operational Description, Additional Infomation Attached please find a revised Aspen Mountain Sununit Program generated by Cottle, Graybeal and Yaw, The program has changed since the Aspen Mountain Master Plan was originally submitted, primarily to avoid slopes over 30%, Additional architectura1 detail will be submitted to the County upon request to aide in the master plan review, however, as Cindy Houben notes in her July 11, 1997 letter, "the Sundeck proposal, to apply for Commercial GMQS, is acceptable," It will be appropriate during the GMQS process to present final architectura1 detail and to determine at that time, appropriate employee generation mitigation, I do understand, however, that as part of the additional information package submitted to the County on August I, 1997, there is additional employee generation information based upon the current Sundeck program, In regard to the County's request for more information about uight use of the Sun deck and the Silver Queen Gondola, I have had extensive discussions with Eric Calderon, General Manager of the Little Nell, who is responsible for operations at the new Sundeck facility, and have subsequently developed the following information, The program includes a cafeteria or scramble operation that it is the same size as the current facility (225 seats) and will employ the same number of employees, The physical area will be re-designed so it is more efficient from several perspectives, including food preparation, serving and cashiering, In addition to a replacement of the existing cafeteria service, there will be two new dining facilities at the Suhdeck. The first is a sit down dining room with 100 seats that is open to the public for both lunch and dinner, The restaurant will be named ''Benedict's'' in honor of Fritz, Fabi and the Benedict family, . Page 1 I"""". .~, The second facility is a sit down dining room with 100 seats that is currently being called the ''Hayden Room." The Hayden Room will be used as a private lunch room during the day and as a public banquet room during the evening, The Hayden Room will be available for use at lunch only by members of a new club concept that is being planned. The new club will offer its members benefits at a variety of Aspen Skiing Company facilities, such as ski concierge service at The Little Nell and signing privileges at the Snowmass Lodge and Club, Lunch at the Hayden Room is only one aspect of the club concept. Both Benedict's and the Hayden Room will serve lunch in the winter, In the summer, only the Hayden room will serve lunch. Benedict's will be closed. (The summer lunch business is not strong enough to support two sit-down facilities,) Both Benedict's and the Hayden Room will be open for public banquet service at night in the winter and in the summer, The Hayden Room, then, is essentially a private lunch facility only and is part of the larger public Sundeck facility in the evening, We are proposing that the gondola and the overall Sundeck facility be allowed to operate for up to 100 nights in the winter season and 100 nights in the summer season, The winter season on Aspen Mountain is now typically 150 days long and the summer season is typically 100 days long, The reason the number of potential nights of operation is the same for both seasons - despite the varying number of days in each - is because summer is a stronger season for group business, The gondola will be operating solely to transport dining patrons in organized groups to the Sundeck facility - the only planned activity at the summit. There are no meetings or conference services planned. There are no other night time activities planned for the summit than banquet-style dining, Dining at the Surtdeck will be primarily for organized group banquet-style dining, The average size of a group that books one of the three rooms available for group functions - the Sundeck, Benedict and Hayden rooms - is expected to be between 75 and 100 people, However, there may one large banquet group on any given night - up to 400 people - but no more than that, While there are 425 seats in the total planned facility, the kitchen facility will be designed to handle no more than 400 dinners at one time, If a group of 400 does book the facility, they will be accommodated between the three different rooms, It should be noted, that while architectural work is still ongoing, it is likely that the Sundeck Restaurant and Benedict's will be adjoining rooms separated be a removable wall. If this is the case, it would provide the opportunity to handle group banquets of between 225 and 325 people in one room, .' On any given night, there may also be three smaller groups that book the different rooms available for banquets - the Sundeck Restaurant, Benedict's and the Hayden Room, This is a . Page 2 ~ ~ far more likely scenario than one large group booking the facility given our expe#ence to date with banquet business at the Sundeck. It is not anticipated, however; that either during the 100 night summer season or the 100 night winter season window of operations, that all three function rooms would be booked on any given night. Indeed, the current business plan for the group banquet facility on top of Aspen Mountain calls for the Sundeck Restaurant to be in use for 45 nights during the summer and 30 nights during the winter, for Benedict's to be in use for 25 nights during the summer and 30 nights during the winter, and for the Hayden Room to be in use for 30 nights in summer and 40 nights in winter, The 100 night ''window'' for planned operations in both winter and summer is just that. Actual use may be less than a total of 200 nights but will not exceed that. It is important to provide a large window in order to provide flexibility in scheduling of banquet business and to provide flexibility for weather-related shutdowns, It will be the sole discretion of the ski patrol team on duty to make a "go/no-go" call each by 5:00 p,m, as to whether or not their will be night operations based on weather and operating conditions, We anticipate that within the 100 day operating window in the winter, there may be as many as 20 nights, or more, when the patrol makes a "no-go" call, The patrol will have complete authority to make this decision based on stonns in progress or forecast. There may be evenings, especially on Saturdays (travel day) in the winter, when there is no group business available for evening banquets, It is anticipated, then, that on about 20% of available evenings, it would be advantageous to be able to offer to the local community the opportunity to experience evening dining on top of Aspen Mountain. The function of the banquet-style operation would not change, Patrons would make reservations, would travel up the gondola in the same manner as a previously organized group, and would be served from a fixed menu at the same time, just as if they were a forma! group, The advantages to banquet-style public dining at the Sundeck facility over an a a! carte type of normal restaurant operation is that is provides for a fixed arrival and departure time on the gondola, eliminates the need for the gondola to be running during the entire evening period of operations, provides for a cleaner decision to be made regarding cancellation of dinner due to inclement weather, and allows for more efficient dinner service during the necessary fixed- time for dinner unique to this type of operation, It is proposed then that there will be one seating for dinner at approximately 7:00 p,m, Patrons must use the gondola between 5:00 p,m, and 7:00 p,m, to access the Sundeck facility, The gondola will cease operation until 9:00 p,m, and will then resume operations to download patrons between 9:00 and 11:00 p,m, The last ride down the gondola will be at 10:30 p,m, During the evening hours of operation, all necessary mountain operations staff will be provided, including lift operators, lift maintenance personnel and lift evacuation personnel. There will be no uploading of ski equipment during the evening hours and no skiing or snowboarding allowed down the mountain at night. No backcountry functions, such as cross- . Page 3 ,"""" .t"'"'\, country skiing, are planned during night time operations, No one will be allowed to access the gondola at night who is not having dinner or working at the Sundeck facility, The banquet facilities will not be utilized during the day or the evening for business meetings or conferences, The facilities are for banquet functions only, . Page 4 f"""\ ~ 1 9 9 7 A spen Mountain Master Plan "i,,;j; ,~.. ..~.. ,~ ,..f,M"..r\"'~ ..~. j"'" ' ."" JIr ~ ..,. ..-,. ~ .1',.1' "'JJ'" 1/1..,.. ....... ~./ ~... . . II..:r" ;t;" ",!ilL ._-''',.,,~,. ..' ,., -.-\~. . ., ,...~ ' ,-.,.. ,-"",,",, . , ':,: ,;..:. ,"...', . . ,........~.......I.'.' .~)I' A u g u s t 1, 19 9 7 Employee Generation Analysis Photo of Aspen Mountain circa 1958 courtesy of Apen Historical Society 1"""'. .~ Aspen Skiing Company Planning Department Memorandum To: Brent Gardner-Smith, Planner for Community Affairs From: Chris Kiley, Transportation and Housing Planner Date: Friday, August 1, 1997 Re: AMMP Employee Generation Per the County's request, I have amended the employment figures for the 1997 Aspen Mountain Master Plan to include Bonnie's, La Baits, ACES, and the current and proposed Sundeck. I have also conducted an FTE analysis for the proposed Sundeck facility, I concur with your recommendation that we meet with Housing Director Dave Tolen to review these analyses in order to fully agree on all assumptions and calculations, 1"""'. ,......'\ , 1996-97 Aspen Mountain Emolovment - Current Conditions Aspen Skiing Company Mountain Operations Employees - Current Department' ,', ' " El'nploy<:eS'; .,Fiill"Tiine ' 'Pan;.'Firiie;, ,. , ','" ." ,", '.:' ,'.,:::.~<. < >:',>,', ' . " '. . ' ,~,. "" ;:.:::~, '. '" i .:...: ...,.'.....'..,.. . . .. ".'...n . . .,.......,...,...,'. .' .. .. ..' ,':\'. " ", ' , ,,',,' .. " Lift Operations 70 62 I 8 Ski Patrol 31 31 0 Ticket Sales" 28 14 14 Guest Services 21 13 8 Lift Maintenance 10 10 0 Snowmaking 7 7 0 Winter Trails 14 14 0 Vehicle Shop 3 3 0 Ski School 125 100 25 Ski School Admin 4 4 0 Gondola Store 0 4 2 2 La Baita Retail 2 1 1 Mountain Photo' 30 14 16 Performance Center 5 5 0 Racing 5 3 2 Powder Tours 15 13 2 Administrative 0 3 2 1 Sundeck Restaurant- Winter" 34 14 20 Sundeck Restaurant- Summer' 17 7 10 Summer Operations' 11 11 0 Total 439 330 109 I Aspen Skiing Company typically uses 32 hours per week for full-time and 20 hours per week for part-time, Departmen1s, unless noted, operate 150 days out of the year, 2 250 days per year 3 250 days per year 4 250 days per year 5 260 days per year 6 Based on 150 days of operation. Sundeck full-time shifts are 8 hours and part-time shifts are 4 hours, 7 Based on 100 days of operation. ' 8 4 lift ops, 3 rangers, 2 lift maintenance, 2 ticket sellers, ro, ,-,. Non-Aspen Skiing Company Mountain Operations Employees- Current The employees listed below work on Aspen Mountain for non-Aspen Skiing Company operations, , COmpany Employees; ,..',Fu,Jl...T:inie ;;.Piitt-'Thne',' ."., Bonnie's 40 54 4 2 100 20 2 2 2 26 20 52 2 o 74 , La Bait ACES-Wint ACES- Summer Total 9 La Bai1a considers 40 hours per week as FT and 20 how:s as PT, 10 BOImie's employees worl<ing 32 hours per week are considered IT and 20 hours PT, II ACES full-time employees work 30 hours per week and part-time employees work 12 hours, /""', I ,--. Aspen Mountain Enmlovment - Pronosed Conditions Aspen Skiing Company Mountain Operations Employees- Proposed Department'zc EIriPloyees :FUll~Tfiijil:' ,.,Parl- Tiriie ., '..' ',. ,',' . ..' Lift Operations 74 66 8 Ski Patrol 31 31 0 . Ticket Sales " 30 16 14 Guest Services 21 13 8 Lift Maintenance 12 12 0 Snowmaking 9 9 0 Winter Trails 12 12 0 Vehicle Shop 3 3 0 Ski School 125 100 25 Ski School Admin 4 4 0 Gondola Store'" 4 2 2 La Baita Retail 2 1 1 Mountain Photo" 30 14 16 Performance Center 5 5 0 Racing 5 3 2 Powder Tours 15 13 2 Administrative 1 0 3 2 1 Backcountry Portal 2 1 1 Sundeck Rest,- Winter Day' , 34 14 20 Sundeck Rest,- Summer Day'O 17 7 10 Sundeck Rest,- Night"' 24 14 10 Mt Hayden Dmlu 17 7 10 Mt, Hayden Night' 12 7 5 Benedict's Day"" 16 6 10 Benedict's Night' 11 6 5 Gondola Ops-Night" 8 8 0 Summer Ops'" 19 15 4 Total 545 391 154 12 Aspen Skiing Company typically uses 32 hours per week for full-time and 20 hours per week for part-time. Departments operate 150 days per year unless noted 13 250 days per year 14 250 days per year 15 250 days per year 16 260 days per year 17 Based on 150 days of operation, Sundeck Restaurant full-time shifts are 8 hours and part-time shifts are 4 hours, 18 Based on 100 days of operation. 19 Based on a totlll of75 nights of operation in summer and winter, 20 Based on 250 days of operation in summer and winter, Shift lengths are same as Sundeck Res1aurant 21 Based on 70 nights of operation in summer and winter, 22 Based on 150 days of operation in winter only, Shift lengths are same as Sundeck Restaurant 23 Based on 55 nights of operation in summer and winter, 24 Includes 4 lift ops, 2 lift maintenance, and 2 rangers for every night event at 1I1e Sundeck (200 nights), "......, !"",,>, Non-Aspen Skiing Company Mountain Operations Employees - Proposed There is no change between existing and proposed employment levels for non-Aspen Skiing Company mountain operations employees, CiiInpaily;' ' ",;Eii1pJoyees ,FuIl~Timee~~iine:' " . ,:' " .....'... . , .' . ..". ." . n.;," ","'". La Bait 40 20 20 54 2 52 4 2 2 2 2 0 100 26 74 Bonnie' ACES- Wint ACES- Summer Total 25 Includes 3 lift ops, 2 rangers, and I ren1al employee from proposed mountain bike program. 26 La Baita considers 40 hours per week as F1' and 20 hours as PT, 27 Bonnie's employees working 32 hours per week are considered F1' and 20 hours PI, 28 ACES full-time employees work 30 hours per week and part-time employees work 12 hours, .",....., !""\ Sundeck Expansion: Employee Generation Analysis Part One: Sundeck Facility Program and Operations Schedule The existing 1000 s,f, kitchen serves the Sundeck only, The proposed 4000 s.f, kitchen will be shared by all three and is allocated based on ratio of seats (1/2 to Sundeck, 1/4 Benedicts, 1/4 Mt Hayden) Operations/ Events Per Season Existing: Sundeck Rest Proposed: Sundeck Rest Benedicts Mt Hayden Winter Lunch Dinner 150 0 150 150 150 30 30 40 100 Summer Lunch Dinner 100 0 100 o 100 45 25 30 100 ,-, .-., Part Two: Labor Hours Per Event Shift Hours Meal Facility Position Employees Length Worked Exisitin!1 Winter Lunch Sundeck Rest. Service 20 4 80 Kitchen 12 8 96 Managers 2 8 16 192 HourslMeal Summer Lunch Sundeck Rest. Service 10 4 40 Kitchen 5 8 40 Managers 2 8 16 96 HourslMeal Pro,posed Winter Lunch Sundeck Rest. Service 20 4 80 Kitchen 12 8 96 Managers 2 8 16 192 HourslMeal Benedicts Service 10 4 40 Kitchen 4 8 32 Managers 2 8 16 88 HourslMea1 Mt. Hayden Service 10 4 40 Kitchen 4 8 32 Managers 3 8 24 96 HourslMeal Summer Lunch Sundeck Rest. Service 10 4 40 Kitchen 5 8 40 Managers 2 8 16 96 HourslMeal Benedicts Service 0 4 0' Kitchen 0 8 0 Managers 0 8 0 o HourslMeal Mt. Hayden Service 5 4 20 Kitchen 4 8 32 Managers 3 8 24 76 HourslMeal r-, ,-.., , , Shift Hours/ Event Facility Position Employees (Hours) Position Winter Dinner Sundeck Rest. Service 10 4 40 Kitchen 12 8 96 Managers 2 8 16 152 Hours/Meal Benedicts Service 5 4 20 Kitchen 4 8 32 Managers 2 8 16 68 HourslMeal Mt. Hayden Service 5 4 20 Kitchen 4 8 32 Managers 3 8 24 76 HoursIMea1 Summer Dinner Sundeck Rest. Service 10 4 40 Kitchen 12 8 96 Managers 2 8 16 152 HourslMeal Benedicts Service 5 4 20 Kitchen 4 8 32 Managers 2 8 16 68 HourslMeal Mt. Hayden Service 5 4 20 Kitchen 4 8 32 Managers 3 8 24 76 HoursIMea1 r--, (1) From Part One (2) From Sundeck Event Schedule Proposed Hours! Year Existing Hours! Year New Net Hours FTE Hours Per Year .,-" 94,060 - 38,400 55,660 New Net Hours 55,660 ! 2,080 26,76 FTE's ,......., ,......., 1 9 9 7 Aspen Mountain Master Plan ,....'" ,1').,' 'IJ,.', I. . ;"<., ... ...',.- ", .' ~~..~:.~.~" . .'-, . " ,~~. '-'" -1::.' " - -" v- '., -~ . ,.", .~ -,' " :. :f';~' . .<0-', " ,'"' ...- ".' .... ~. . ".. ~"-"'-..., ... -,.,.., _.".,~ '-"""\.01::: 'I." .....,.~"'4::11 _ "" ,," ~~: .fI. ,..........' , ,.. .", ,~~...I'.". .',. , A u g u s t 1, 1 9 9 7 Traffic Analysis Photo of Aspen Mountain circa 1958 cowtesy of Apen Historical Society AUG 01 '97 14:08 FR FHU f""", 303 721 0832 TO 19709234875 .~ P,02/07 F E l S 8 U R G HOLT & U l lEV I G I August 1, 1997 Mr. Brent Gardner-Smith Planner for Community Affairs Aspen Skiing Company 5131 Owl Creek Road Snowmass Village. Colorado a 1615 RE: Aspen Mountain Master Plan FHU I"rojcct # 95017 Dear Mr, Gardner-Smith: As you requested, we have reviewed the potential transportation and parking impacts which might result from implemematior1 of the Aspen Mountain Master Plan. Our report is attached. We have determined that the reconstruction of the Sundeck Restaurant and summer mountain biking activity would have the most potential for changing patterns of use at the base of the mountain and have therefore concentrated our analysis on these 3ctivitie$. Sinct:naly, FELSBURG HOLT & ULLEVIG ~!~ David E. Hattan, P,E. Associate Speciah"mg in T:anspcrtalion and Civil En.!:Jineerir:c: 5299 DrC Boul9liard . SullQ ~oo Englewood, Colorado 801 , 1 ... (303)721-HAO ru(3O>"72',.... AUG 01 '97 14:08 FR FHU 1""""'-. 303 721 0832 TO 19709234875 ,^, P,03/07 ASPEN MOUNTAIN MASTER PLAN OVERVIEW OF TRANSPORTATION AND PARKING IMPACTS FROM SUN DECK RESTAURANT RENOVATION, NIGHTTIME OPERATIONS, AND SUMMER ACTIVITIES The 1997 ASDen Mnuntain Master Plan. prepared by the Aspen Skiing Company and released in May 1997 proposes a number of improvements, almost all of which are upgrades to existing facilities, Infrastructure improvements are necessary to replace facilities which are reaching their design life or are becoming functionally obsolete, In addition, the ski area must stay competitive with other resorts in order to maintain its standing as a world-class facility, It is important to note that the Master Plan does not involve a change in the basic operations or capacity of the ski area. In fact, one of the goalS contained in the Master Plan is to "improve the skiing and guest experience on Aspen Mountain without. a significant increase in mountain capacity beyond the existing rated capacity of 4.300 skiers per day". Thus, it is felt that any impacts to transportation and parking systems at the base of the mountain will be limited. In reviewing the proposed Master Plan and its effect on transportation and parking, it is also important to point out that Aspen Mountain is unique, It is one of the few ski areas in the United States that doesn't have a large parking lot for vehicles at its base. Aspen Mountain adjoins the commercial area of downtown Aspen, and there are numerous residences (hotels, lodges. condominiums, arid single family residences) within convenient walking distance of the base area lifts. Since Aspen Mountain opened in 1946. it has become part of the fabric of the City of Aspen, Because Aspen Mountain is so intimately tied into the fabric of downtown Aspen, it is difficult to separate out the impacts of current skier actiVitY from normal/commercial activity in the surrounding area. In order to begin to address the potentiai impacts of the proposed Master Plan improvements, this memorandum win address quaiitative aspects of the concerns, More detailed, quantitative information will become available during the 1997-1998 season as the Aspen Skiing Company will conduct an .origin.destination" survey of Aspen Mountain skiers, The Master Plan proposes several changes which may have some affect on the transportation and parking systems in downtown Aspen, and these are the primary focus of this analysis, These Improvements include reconstruction and expansion of the Sundeck Restaurant; evening use of the Silver Queen Gondola, Sundeck Restaurant, and La Baita Restaurant; and expansion of the terrain available for mountain biking activities in the summer, This review has been divided into five sections: Proposed Improvements Being Analyzed, Background and Current Conditions, Winter Daytime Operations, Winter and Summer Nighttime Operations, and Summer Daytime Operations. 1 AUG 01 '97 14:09 FR FHU ~. 303 721 0832 TO 19709234875 ,--" P,04/07 PROPOSED IMPROVEMENTS BEING ANALYZED As mentioned previously, the improvements included in the Master Plan are not intended to increase the capacity of the ski area and thus will have no adverse impacts on the transportation and parking systems in Aspen for the most part. The following Master Plan improvements are expected to change operations to some degree and are therefore the subject of this memorandum; . Reconstruction and EXDansion of the Sundeck Restaurant - The Sundeck Restaurant is one of three restaurants at the ski area and is located at the top of Aspen MouTltain, It was originally constructed in 1957 and currently includes a 7,700 square feet building. The building has a maximum seating capacity 275 people indoors (although the practical seating is only 240) with an additional 80 people on the deck. Expansion of the restaurant to approximately 20,000 square feet was approved in 1987, The current plan is to save part of the original building and expand it to 21,700 square feet, There would be three dining areas: a cafeteria with the capacity of 225 seats, a public sit down dining room with 100 seats, and a private sit down dining room with 100 seats. The private room would be operated at midday as a "lunch club" for members only. The cafeteria would serve food all day, but daYtime activity at the two dining rooms would be concentrated between 11 :00 a.m. and 2;00 p,m, The Master Plan envisions that the new building could also be used at night for group banquet service and individual banquet style dining. Any of the three rooms could be reserved for group events, There would be a moveable wall between the cafeteria and one of the dining rooms so that larger groups could be accommodated. The kitchen facilities for meal preparation will limit the maximum number of people who can be accommodated to approximately 400 diners, However, the average size of group is expected to be 75 to 100 guests, . Niahttime Operation of the Silver Queen GOndola. The Silver Queen Gondola would transport guests up and down the mountain when there is an event .at the Sundeck Restaurant. On these nights, the gondola would run from approximately 5:00 p,m. to 7;00 p.m, to bring guests up the mountain, The gondola would then run from approximately 9;00 p.m. until 11 :00 p.m. to bring them back down the mountain, It is expected that everyone would leave the Sundeck by 10;30 p,m, in order to be down by 11,00 p:m, Banquets could be scheduled any night of the week during the winter and summer seasons. but there would be a maximum to the total number of nights allowed during the season, as discussed in following sections. . Niahttime Use of the La Baita Restaurant - The Master Plan includes a request to use' the La Baita restaurant for a total of 10 evenings in each winter season. This will primarily consist of catering private functions and parties, The maximum guest seating capacity at La Baita is 100 people, The guests would be transported to the restaurant, via snowcats, Arrival and departure times would be standardized, and guests would meet the snow cats at the Shadow Mountain Lift at standard preset times, The operation of snow cats is already occurring at these hours during full grooming operations. 2 AUG 41 '97 14:10 FR FHU ~. 303 721 8832 TO 19709234875 ~ P.05/07 . Summer Mountain Bike Proaram - Lift-served mountain biking has been conducted on Aspen Mountain on a limited, experimental basis during the summers of 1995 and 1996. Bikes were transported up the Silver' Queen Gondola, and riders were encouraged to use routes along Richmond Hill or down to Castle Creek Road as opposed to using the front side ,of Aspen Mountain. The Master Plan proposes a coordinated program of lift and trail use on Aspen Mountain during the summer with an emphasis on using new trails on the front side of the mountain, In addition to the Silver Queen Gondola, Aj<lx Express and other lifts ias deemed appropriate) would be used to transport mountain bikes, A top-to-bottom network of trails would be developed to serve intermediate and expert mountain bikers. Lower mountain facilities, such as Bonnie's Restaurant. may operated in conjunction with the mountain biking program. BACKGROUND AND CURRENT CONDITIONS As mentioned previously, Aspen Mountain has a unique transportation and parking system because of it close proximity to the City of Aspen and the downtown commercial area and nearby residential areas, Parking at the base of the ski area is very limited so Aspen Skiing Company (ASC) highly encourages use of alternative transportation, ASe contributed $1,216.461 to the Roaring ForkTransit Agency (RFTA) during the 1995.1996 ski season for operation of the free skier shuttle. Buses run continualty during the seaSOn to Rubey Park and transport skiers from Snowmass Village and Bunermilk (inn at Aspen) to downtOwn Aspen, While many of the users of the skier shuttle are based in Aspen and use the buses to get to and from Aspen Highlands, Buttermilk, Two Creeks at Snowmass, and the Snow mass Mall, the skier shuttles also move a significant number of skiers to Aspen Mountain. Skiers staying within the City of Aspen oan also use the regular transit serviee which is free on routes within the city, Local lodges also operate private vans and smalt buses which shuttle guests and groups to and from the ski area, Taxis and limousines are also available to Aspen Mountain skiers, Finally, there is a large bed base which is within walking distance of the mountain base. Ase encourages the use of mass transit by all employees. ASC employees are able to purchase a $40 RFTA punch pass for $5 through the company, and recent surveys indicate that approximately 40% of ASC employees regularly use transit, The number of Aspen Mountain employees U!ling mass transit and walking to access their workplace is likely to be higher given that many live in Aspen. With 'regard to parking at Aspen Mountain, ASC controls two parking areas: the Aspen Street parking lot and The Little Nell Hotel parking garage, There is a 30-space parking lot on Aspen Street near the Shadow Mountain {Lift #1A} base area which is free tor employees and guests on a first-come, first-serve basis, The Little Nell Hotel has an underground parking garage' with 150 parking spaces; 43 spaces are currently available to skiers on a daily, monthly, and seasonal basis, In addition, day-skier public parking is available at the Rio Grande garage. There are 340 spaces in the garage at a cost of $5 per day. There is a free shuttle through downtown Aspen which provides service between the Rio Grande garage and the Silver Queen GOndola. The Galena Street Shuttle runs during the winter and summer seasons between 8:15 a.m. and 5;16 p.m. The two vehicles provide five to seven minute headways along the route. 3 AUG 01 '97 14:10 FR FHU r""'" 303 721 0832 TO 13709234875 r""'" P,06/07 Finally, ttlere arll 1;IiJiJruxirlli:ll..ly 670 iJulJli" p..,k,illg SP""'" UII ll... Sll"''''ls uf t.!uwnLuwn A.pen, There is a two-hour maximum time limit and a charge of $1 per hour. Paid parking hours are between 7:00 a,m. and 6:00 p.m. A tew streets have overnight restrictions tor snow plowing, WINTER DAYTIME OPERA TrONS The reconstruction and expansion of the Sundeck Restaurant is unlikely to have a noticeable effect on daytime transportation and parking in Aspen. The improvements are intended to replace outdated facilities, to reduce peak period {lunchtime} congestion at the restaurant, and to provide guests with a better dining experience (particUlarly at the two sit down dining rooms) with faster service. It is not expected that additional skiers will visit Aspen Mountain because of the renovation. The Silver Queen Gondola currently carries a limited number of "foot" passengers, These are people who are not skiing and use the lift for other reasons. Statistics for March 1997 show that this amounts to approximately four percent of the total uphill activity at the ski area. It is p05sible that the new Sundec;k Restaurant will increase the toot traffic; pas5enger5 because of the new sit down dining rooms, However, it is felt that this increase would be relatively minor, particularly in comparison wittl the large number of skiers using the mountain. It is also possible that any initial increase may taper off after people have done it once or twice - depending on how unique the food and dining experience are, WINTER AND SUMMER NIGHTTIME OPERATIONS As described previously, ASe is proposing that nighttime use of the Sundeck Restaurant would be limited to banquets style events. ASC is requesting to be allowed to use the Sundeck for up to 100 nights during the winter and up to 100 nights during the summer, In addition, there is a request for up to 10 events at La Balta during the winter only. ASe is estimating that up to 80 of the nights for the Sundeck Restaurant would be group banquet service, It is expected that there might be approximately 20 large events (up to the 400 guest maximum - although it is eXIlMTed ThaT the maximum would be reached only once or twillA ~ ~p."'~nn) ..nn An ~m..1I events {up to 100 guestsl. The other 20 nights would occur when no organized groups have reserved the rcstour"nt, On these nights, service would consi..t of individuQI banquet-style dining. It would operated much like a banquet in that there would be a fixed menu and a set time for dining, but each small group would make individual reservatiOnS, There might be approximately 50 guests on these nights. If there are not sufficient reservations for an evening, the restaurant would not open, With regard to nighttime transportation and parking at the base of the Silver Queen Gondola. it is anticipated that a number of the larger groups r.nuld I'll'> rmr(lnrRte meetings being held at the Ritz-Carlton, which is the largest hotel in Aspen. The Ritz-Carlton is located two blocks W<lst of tnEl gondola <ind would be within easy walking distance. For other:;; not staying within walking distance of the Gcndola, a number wouid probably avail themselves of shuttle vans operated by their lodge or use nrTA buses at Rubey Park. People driving ,,;;IIS wuulu Uti 1;11;1", to use on-street parking since the two-hour limit is not applicable aiter 6;00 p,m, However, on-street parking is currently well utilized during the winter, partiCUlarly dunng peak holiday periods, There are nO comparable statistics available to estimate how many guests might use 4 H1.JU I::Jl .":::;! ( ~';';'..J..J. r-i"t' r-HU ~I::J~ .. ~J. :..::Jd"::'::::: : li l,;! (l!I':I,::".>.I-C)' (::, t"'.1::J r/~ ( r". !""""\, each mode IIf tn:III>;lJu'l"tiun, A conservative estimate of the number of oers which might reCluire parking for the Sundeck ranges between 20 and 80 as a maximum, Compared to the amount of parking available and thE! level of nighttime activity in downtown Aspen, nighttime events at the Sundeck Restaurant are expected to have only a reiatively minor impact. The 10 events requested for La Baita have already been described. The 30 parking spaces at the base of the Shadow Mountain Lift would be available for use by the guests. The remainder ore expect to walk to the lift or be drClpped of by Shuttle vans from their lodoe, SUMMER DAYTIME OPERATIONS The primary daytime use proposed in the Master Plan for the summer season is expanded mountain biking, Appendix 6 of the Master Pian is a detailed report of mountain bil;ing activity during the summer of 1996, It is estimated that a total of 2.317 mountain bikes used the Silver Queen Gondola to aCcess the mountain, Thp.rA WM l'ln l'lvp.rllge of 42 bikes per day with peak summer weekends having an average ot 71, The three largest days saw' 60, 120, and 65 bikes on the gondole. re",pectively. It is reasonable to expect that Increasing the amount of terrain a"..iloble fur "'<,>ulll";" llikill\l and opening the front side of Aspen Mountain will increase the level of activity, However, no forecast of specific activity levels has been developed. The new trails on Asper Mountain are expected to serve intermediate and expert mountam bikers, Unlike skiers whc are relatively immobile because of ski boots, these mountain bicyclists are much more mobile and are able to ride longer distances to access th.. mnllntllin. MMt 1J!~p.rs who live or are staying within the city would be expected to ride their bike to the gondola. Others might use RFT A buses, which are equipped with bike rccl(G during the spring, summer, snd iall (except for routes within -:he City of Aspen) , These have proved to be very popular with bike riders, The main transit stop In Aspen at Rubey Park is very corwtllliell' 'u Un. YUlluuli., OUn'l ddill$ living furth"r away who drive a car would be able to park at the Rio Grande and then ride their bikes to the gondola, On-street parking would probably not be greatly useCl because ot the two-hour time limit, If the lAVAl "t "ntivity doubles from that experienced on the peak day during 1996. it is conservatively estimated that 40 vehicles might be parked in the Rio Grande garage. Thus, It is cxpccted that doytime impact;; to downtown Aspen and its transportation and parking systems during the summer will be relatively minor, CONCLUSIONS Because the Master Pian does not involve a change in the basic operations or capacity of the ski area,. it is felt that any impllcts to transportation and parking systems at the base of the mountain will be limited. Specific reviews of the new Sundeck Restaurant. ni;httime operations, and the summer moumain biking program also reveal that traffic and parking impacts in downtown Aspen are expeoted tc be relatively minor. ,5 ** TOTIiL PffiE, 07 ** 1"""'\ .~ Aspen 199 Mountain 7 Master Plan ~.,'~' ~;t+' : ,-';: . l~;~.' .. ,j~". !/~I!J')I', 14lr. IfI' 'Q'.........-.....," " v,' "-,..,:; . ,,.,,,," ,..'\;O~~~~.'!.~~~ .. ..::. . !'...)O;;..~" ."'" .. ,....'. ........~....,...I". ./l~ A u g u s t 1, 19 9 7 Lighting Analysis Photo of Aspen Mountain circa 1958 courtesy of Apen Historical Society 2340 Plaza Del Amo Suite 125 Torrance California 90501 . 1"", r1 I PATRICK QUIGLEY 'It + ASSOCIATES July 29, 1997 Mr, Brent Gardner-Smith Aspen Skiing Company 5131 Owl Creek Road SnowmassVillage, CO 81615 Re: The Sundeck Restaurant and Upper Gondola Tenninal Buildings Lighting - Preliminary Environmental Impact Study of Existing Structures and Mitigating Measures Dear Brent: Patrick B. Quigley + Associates (PBQA) was summoned by the Aspen Skiing Company as professional lighting designers to review the environmental impact of existing and future lighting on the local environment. 310533.6064 Fax 310 320w34B2 The following report outlines the Sundeck Restaurant & Upper Gondola Tenninal Buildings environmental setting, existing lighting systems and how these systems are used as currently operated, This section is followed by both specific, recommended mitigation measures for the existing structures, as well as general design criteria for any future nighttime use of these or other structures at this location, I. EXISTING CONDITIONS A. Environmental Settina . The upper Gondola Tenninal Building, Sundeck Restaurant and their smaller support structures are located on the top of Aspen Mountain, in the Rocky Mountains of Colorado, The general area is characterized by low level "night sky illumination" (light pollutionllight trespass) immediately surrounding the City of Aspen, fading to "black sky" conditions in the mountains past the ridge lines adjacent to the City of Aspen. There are light fixtures existing today on Aspen Mountain and they have been there for ten years, facilitating maintenance, security and low level use of both the Gondola Tenninal and Sundeck Restaurant. B. EnvironmentallmDact . The mountain top facilities can be seen at night from off.site viewpoints at isolated roads and homes around the Aspen area, Those impacted specifically include portions of; road and trail north of Hunter Creek (6 miles approx,); road north of Lenado, Larkspur Mountain and ridge between Woody Greek and the Frying Pan (10 miles approx,); Red , barn on East Owl Creek Road and adjoining subdivision (6 miles approx,); Snowmass Golf Course at area of Meadow Road and intersection of Brush Creek Road and Melton Aspen Sundeck Environ. Impact 29 July, 1997 Page 1 of7 I Architectur-ai Lighting Consultants 2340 Plaza Del Amo Suits 125 Torrance Caiifomia 90501 310 533-6064 Fax 310 328-3482 1"'"". ,-'. PATRICK ,m'" I + ASSOCIATES Ranch Subdivision (subdivision north of golf course) 8 miles approx,; Hidden MeadoWs Subdivision north of Krabloonik Road (10 miles approx, one home visible); Conundrum Creek Trail small section visible (3,5 miles approx,~ Nye house on Ultle Annie (.5 miles approx,), Likewise, the site can not be seen from; the Town of Aspen, Highway 82 up- valley, Highway 82 down-valley, the airport, Woody Creek, the base of Buttermilk Mountain, the base of Aspen Highlands, Ashcroft, Castle Creek Road, Maroon Creek Road and area campgrounds, If they are in 1I1e higher elevations, recreational users of the surrounding mountains such as hikers and cross country skiers may also experence a nighttime views of these facilities, Though these views are extremely limited, they are of significance due to the area's historic preference for an unintenupted silhouette of the mountain ridges against the night sky, The minimal use of exterior fixtures means that these buildings' contribution to the night sky illumination is nominal. Any such contribution is overwhelmed by the street and facade lighting of Aspen City below. II, CURRENT OPERATIONS AND SPECIFIC MITIGATION A. The Gondola Terminal Buildina Current operations at the Gondola Terminal Building include nighttime security and maintenance activities, as well as transporting patrons to the restaurant. Existing illumination systems and recommended mitigation include: 1, Gondola Building Exterior. a) A single high intensity discharge (HID) "wall pack~' type fixture rrounted on the west facade, overlooking the public entry portal. This fixture type is characterized by high glare and indiscriminate light distribution toward the horizontal ground plane, the sky, and everything in between. Mitigation calls for this fixture's replacement by a well shielded unit that directs its light toward the ground plane only, b) The vehicle maintenance facility at the east end of the structure has a large roofed, open sided staging area, The area is now used at night in the winter, Mitigate by using shielded fixtures that limit illumination to the ground plane, such as a 'long barreled' ceiling mounted down light. Aspen Sundeck Environ, Impact 29 July, 1997 Page 20f7 I Architectural Lighting Consultants 2340 Plaza Del Arno Suite 725 Torrance California 90507 310 533-6064 Fax 310 320-3482 r"'"'"'. ('\ I' :~:fb QUIGLEY !lW + ASSOCIATES PATRICK 2, ' Gondola Building Interior: a) The bUilding interior lighting is made up entirely of non-shielded fixtures including bare fluorescent strips and incandescents in the office and tunnel (where cabins first enter the facility), and HID "wall packs" in the loading room and gondola storage areas, While the cumulative systems provide an appropriate level of work light, their use also results in a very high level of interiOr glow as seen from outside the structure, Specific mitigation measures should include mEl:hanized shading devices in the loading area located along the south facades window wall, The same technique should be used at any window exposed to an off site view, such as the office, These shading devices should be controlled bya photo cell or timer device, b) Eight of the HID wall packs in the loading area are left on all night for security purposes and provide a reasonable ievel of light. The mitigation noted above will negate the current impact of this all night system, 3, Additional Illumination of Gondola Cabs: If night use is approved, then additional illumination should be provided between the Gondola Terminal Building and the last tower for operators to see whether the cabs are swinging due to high winds, Mount an HID, low wattage, narrow flood at tunnels' north exterior facade, Equip fixture with louver and/or other glare mitigation device, Alternative location is under the arrival portal, on the wall, to uplight incoming cabs, B. The Sundeck Restaurant Current operations include dining for individual groups on an extremely limited, special permit basis, All lighting systems stay on for clean-up followed by a late night security setting, In the winter, kitchen and snack bar lighting along with selected circuits facilitating access, are used by the prep cooks who often work until late into the evening. 1, Sundeck Restaurant Exteriors: Aspen Sundeck Environ, Impact 29 July, 1997 Page 3 of7 I Architectura" Lighting Consultants 2340 Plaza Del Arno Suite 125 Torrance California 90501 .1""'\ ."-'. ""''' '""''' I + ASSOCIATES a) 'Jelly jar' incandescent fixtures are mounted on the walls adjacent to the south and southwest facing sundecks, Though low wattage, these fixtures are similar to 'wall packs' in their omni-directionallight distribution and indiscriminate glare, These units are among the most \isible fixtures from off-site views and are currently left on all night. These fixtures should be either shielded or replaced with new, glare controlled down lights resulting In illumination of the hori:wntal plane of the deck only, b) Ceiling mounted wall pack at north covered stairway is baffled from exterior view except at flanking windows, Mitigate by supplying a shielding collar, c) Tents - Currently large tent structures are available for banquets during the summer only, Use of these tents is extremay limited by the same special use permit requirement that governs the restaurant. The restaurant and tent seating is not used concurrently, The impact of the tent(s) at night can be effectively mitigated through proper siting based on offsite views and through opaque flaps hung on sides visible from off site. 310 533-6064 Fax 310 320-3482 2, Sundeck Restaurant Interiors: a) The two levels of interior seating are lit primarily by adjustable, incandescent ceiling mounted "mono point' fixtures. They are arranged in two, octagonal donuts in plain view at approximately 6' and 12' from the perimeter wall, Some of the fixtures are currently aimed such that direct lamp glare is seen from outside, The obvious mitigation for this system is to aim these fixtures universally away from the windows and toward the room's interior, This alone, however, leaves the perimeter tables against the window unlit. PBQA recommends addirgan additional donut of fixtures immediately adjacent to the perimeter wall, These fixtures should be aimed away from the glass while still being able to illuminate these tables, The new fixtures will provide an added daytime benefit - - helping skiers adjust from the in\:lnse sunlight outside to the relative darkness of the restaurant. b) The innermost of the interior octagon forms is currently lit by soffit mounted up lights, Due to the exterior visibility of the lit ceiling plane, we advise: a) Dimming this CKT down significantly, or b) Replacing with a new system of low voltage down lights that illuminate the inside faces of the columns, as well as the columns at the fireplace, The two systems 29 July, 1997 Page 4 of7 Aspen Sundeck Environ, Impact I Architectural Lighting Consultants 2340 Praza Del Amo Suite 125 Torrance California 90501 r"', ,-.., I %1 PATRICK QUIGLEY + ASSOCIATES could be used together, c) "Wrap around" lensed fluorescent fixtures, ceiling mounted over mack bar is a source of high glare, Install a wood frame around the fixture and equip with 1/2'x1/2"x1/2" white acrylic 'eggcrate'louver, , III, FUTURE OPERATIONS AND ACCOMPANYING LIGHTING MITIGATION CRITERIA PBQA's understanding of future operations as proposed by the Aspen Skiing Company is for a year round banquet dining facility, open up to seven nights a week with the last down mountain Gondola cab at 10:30 P,M, The facility wouid be booked on demand, 310533-6064 If all of the specific mitigation measures listed in previOUS sections of this report are acted on, the result will be a significantly reduced impact to the nighttime view corridors toward the structures, Whether the operating hours are extended or not, the direct glare of lamps and interior glow at night will be greatly reduced from current levels, In addition, sky illumination should be the same or less than existing levels due to proper1y shielded fixtures. Fax 310 320-3482 Besides the mitigation previously mentioned, we believe the following items represent important additional design criteria, Regardless of what agreement the Aspen Skiing Company and the Community may come to, these crteria will help ensure a sensitive nighttime treatment of this delicate environment. A The lowest applicable Illuminating Engineering Society's (IES) recommended footcardle (FC) levels should be provided, . walkway and decks at .2 FC with illumination uniformity ratios of 4:1 to 6:1 (average to minimum), B, Wherever possible, screening features such as trees, berms, walls, topographic features and architectural elements should be utilized to hide fixtures from view and trap light at the ground plane, C, To minimize the lighting's impact, the fixtures used will feature the following characteristics: 1. Low levels of lighting provided by "warm' toned (2,500 to 3,000 degrees Kelvin temperature) lamps, 2, Physical characteristics of lighting equipment shall be forms, materials and finishes that are compatible with the adjacent surroundings (Le, wood posts, earth tone finishes, stone), Aspen Sundeck Environ, Impact 29 July, 1997 Page 5 of7 ,I Architectural Lighting Consultants 2340 Plaza Del Amo Suits 125 Torrance California 90501 "-.,, ~, PATRICK I QUIGLEY 't1! + ASSOCIATES 3, Fixtures shall have distrtbution types and cut-off charactertstics that limit spill light onto vertical surfaces such as plants and buildings that can be seen from off-site, The fixtures used shall typically be of a shielded downlight vartety, ' 4, To prevent glare, fixtures shall have optical control based on proper placement of light source within fixture and proper design of reflector and lenses, Glare mitigation devices such as baffles, louvers and shields will be used as required, D, Fixtures shall be ortented to minimize off-site impact (Le, the maximum candlepower shall be aimed away from the off-site viewer and the physical untt shall be located on the shielded side of visual barriers, such as trees and walls), E. Extertor and intertor building matertals shall be non-reflective and use natural, subdued tones, 370 533-6064 F, Lighting of signage shall be kept to the minimum practical footcandle level required for successful identification of destinations, All sign lighting, , if required at all, shall utilize non-glare down light fixtures, No neon or self-illuminated signage shall be permitted, Fax 310 320-3482 G, Other than signage, no direct vertical illumination, such as facade washes or landscape accent lighting, shall be allowed wtthin the off'site view corridors into the project. H. Impacts from night-lighting on wildlife in neighbortng habitats shall be resolved through shielding, directing lights away from adjacent open space, using lower-intensity lights, and using automated controls to limit light usage to those times ifs needed for guest use and maintenance, followed by lower levels needed for late night safety and securtty. I, Though a lower overall impact can be expected on noctumal wildlife if all mitgations are followed, PBQA's lack of familiarity with local species precludes us from commenting on this subject in an authorttative manner, IV, CONCLUSION As the two facilities exist today, little, if any glare or night sky illumination mitigation exists, The fixtures are brtght and have some impact on distant views and noctumal wildlife, Even so, the view corridors into the project are extremely limited and, in most cases, quite remote. We are comfortable saying that if the specific glare mitgations and design crtterta are followed off site views to the projects will be reduced, The views that remain will be noticeably and positively impacted by significant glare reduction, Whether the restaurant hours are extended or not, the cumulative mountain top facilities will have a reduced environmental impact rom the existing conditions, 'Indeed, if the Gondola Terminal and Sundeck are used for nighttime operations and the recommended mitigations are implemented, the likely impact will be less Aspen Sundeck Environ, Impact 29 July, 1997 Page 6 of7 I Architectural Lighting Consultants 2340 Plaza Del Amo Su#e 125 Torrance California 90501 .,-.." ,-." PATRICK I aUIGLEyHIl + ASSOCIATES than currently exists, PBQA anticipates lower levels of night sky illumination if these measures are adopted and the operations stay the same. Or about the same level as exilts today if operations are expanded as described by the Aspen Skiing Company, and noted in this report, 310533.6064 Fax 31 a 320.3482 Aspen Sundeck Environ, Impact 29 July, 1997 Page 7 of 7 I Architectural Lighting Consultants r-\ f""".. Aspen 199 Mountain 7 Master Plan ..""-., ~'r..lli ~ ....II!".. . ../,L ".!!"".,, 11 ~"r. Ifl...,:.... - >.~' ' ',," At I', ." ':~." /' "")I ',~ #~ .> ."r".. '.,,,- .~ ....., ;,..,..; .,;,~..,r,~J.o::.""""'.", ._...,.- ''Io'','.:.;:'''~ "~(~~ "'..ri ,,":, ", ,:".:: -,,...:;;,,,"::,:,.,... ,/ ,.;Mo,.I ,~" A u g u s t 1, 19 9 7 Surveyor '8 Report Photo of Aspen Mountain circa 1958 courtesy of Apen Historical Society ~