SITE LOCATION & CONDITIONS master plan
first phase commercial core mountain development plan potable water & sewage disposal schematics topographic map geological conditions land use development plan soils and geological formations
SITE CONDITION DETAILS geology soils
hydrology & flood plains slope analysis sun-shade analysis vegetation ranges wildlife habitat commercial core
wildlife aquatic habitat climate
FUNCTIONS AND SPATIAL REQUIREMENTS
The proposed Adam's Rib Recreational area is located at a latitude of 39 degrees 30 minutes, and a longitude of 106 degrees 37 minutes 30 seconds, which places it in south-central Eagle County, within the East Brush Creek Valley 16 miles south of the town of Eagle, Colorado. Physiographically, the area is at the north end of the Sawatch Range of the Central Rocky Mountains, and lies within the Colorado River drainage. Elevations of the study area, vary from 7,600 feet at the lowest point of East Brush Creek Valley, to 11,144 feet to the peak of Adam's Mountain. Yeoman Park, where the commercial core and residential condominiums will be built, varies in elevation from 8776 feet at the north end, to 9092 feet at the south end. Charles Peak rises beautifully to form the East Brush Creek drainage.
The project will encompass about 25 years of planning and building from start to finish. This will include a 250,000 square foot multi-use commercial core and numerous condominium units spread throughout the park. Also included are two championship golf courses incorporating their own facilities between Yeoman Park and the town of Eagle. Adam's Rib is planning to be a major year round resort emphasizing the overnight, and week long guest facilities. The era of the day skier is considered uneconomical, and therefore relatively unwanted, which includes transients, and local residents who do not live in the Adam's Rib
Recreation area boundaries.
For my thesis project, I am going to investigate an alternate re-massing of the commerical core. I will then proceed to concentrate on one, or a combination of, the buildings contained within the core project. The original Master Plan of Yeoman Park, and the present location of the core site will be retained and used in my thesis work.
I will focus my attention on harmonizing the structure as uniquely as possible to the site by keeping topographic, and vegetation disturbance to a minimum. The careful selection of views, use of sun, and use of appropriate facade and interior materials will of course, be most important. I wish to carefully facilitate the interaction of the human and the shelter, to the surrounding enviroment.
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PROBLEMS AND IMPACT OF ADAM'S RIB
The Adam's Rib Recreational Area has faced a long and difficult trail to its present status. Proposed by the HBE Corporation of St. Louis in 1975, Adam's Rib was considered as an alternative site for the 1976 Winter Olympics to be held in Colorado. The resort proposal faced opposition when Governor Lamm, and the citizens of Colorado expressed their discontent with the Olympics and therefore to the recreation area itself.
Adam's Rib has also discovered a hard line with the Colorado Review Commission, which was formed by Lamm to impede the progress of Adam's Rib and others proposals like it. The Commission is composed of four committees, one each from the city, county, Forest Service, and the clients themselves a no confidence vote by any or all of the committees cancels the current proposal. Since 1975, the HBE Corporation withdrew the proposal once, and resubmitted at a later date.
The city and county of Eagle cannot review or reject the proposal based on aesthetics, as beauty is vague, if not extremely difficult to legally determine. (However, an architectural review committee appointed by the client can be formed).
The city and county of Eagle will feel a tremendous impact if, and when, the Adam's Rib recreational area becomes reality. According to the Eagle Planning Office, the present community
seems to be divided 50-50 on the proposed development. The business sector welcomes the project as a valued source of revenue for themselves, and an increase in the services that would be attracted to the local area with the subsequent services offered. The "urban escapees" group is resisting the ski area project for the same reasons, they do not want rapid growth around Eagle, but wish to continue the slower pace of the small town. The remaining people are the group that has lived in the area for most of their lives, and do not want the fabric and scenery of Eagle, and the surrounding area changed by large growth and development. They have grown up in a small ranching community, and at this moment are now watching the small ranchers being overtaken by large corporations.
The time I have spent conversing with the local population and reading the local papers, seems to indicate that the percentage of non-growth advocates is slightly higher than reported.
The economic impact alone will be staggering. The Eagle Planning Department forsees an enormous number of construction workers needed to build the resort over the next 25 years. The public and private business facilities that would be necessary to provide services for the workers and others, is estimated at 11,000 to 17,000 people at any given time during the season.
Services cannot possibly be provided by the city and county, as Eagle has trouble enough housing the immediate population right now.
Finally, the resort users themselves will pressure the present housing, and public services to their limit. Therefore, the community of Eagle must prepare a thorough and extensive plan now, so that the impending development due to Adam's Rib does not become another "condo ghetto" such as Vail.
Eagle Planning Department Eagle, Colorado
10 July 1981
The Eagle Valley was first inhabited by the Ute Indian Tribe, with Cheyenne and Arapahoe hunting parties providing at least seasonal occupancy in the valley for thousands of years. The land had technically belonged to the Utes by treaty, but this did not in any way inhibit or discourage exploration, prospecting, hunting or fishing by the white man. In 1845,
John C. Fremont led an expedition in which Kit Carson and other "mountain men" scouted. In 1874, a geological team led by Frederick Hayden explored the valley noting the mineral wealth, and other geologic formations.
First permanent occupation occured when the town of Redcliff was established in 1879. Redcliff served as a transportation depot for foodstuffs and other goods to the surrounding mining towns, and became an embarkation point for westward explorers and settlers. In 1882, the Homestead Act was approved by Congres which effectively eliminated the Indians righful claim to the valley, and the Indian Cheif Ouray with his people were not to inhabit the valley again.
The town of Eagle came into existence in the late 1880's, when William Edwards claimed 156 acres at the mouth of Brush Creek. At first it was called Castle, after a volcanic outcrop prominantly located near the town. Henry Hernage arrived in 1882 when he settled above Edwards claim.
By this time, logging, hunting, and fishing had become both popular and profitable, and the Denver & Rio Grande Western Railroad extended itself through the valley down to Glenwood Springs. The railroad proceeded to build and operate a station at Castle, and gave it the name of Rio Aquilla (Eagle River), believed to be the first such naming of the valley. However, the name was to be recorded in the Colorado Business Directory as the Eagle River Crossing. By this time, the town now had a general store, post office, and a blacksmith.
In 1895, a man by the name of A.A. MacDonald purchased the townsite and named it after himself, but a year later MacDonald and his town were out of business. Shortly after he left, Eagle had the "Eagle County Examiner" in 1899, its first newspaper edited by Mr. Hildreth.
Ranching and agriculture grew tremendously, as an estimated 10,000 acres of farm land, and 1,500,000 acres of grazing land brought many hopeful people to the area. Agricultural cash crops included lettuce, potatoes, and other hardy vegetables until the beginning of WW II. Since then, ranching has returned as the major economy of Eagle and the town has been a ranching community since. Yeoman Park, the base facilities site for Adam's Rib, is currently used as a camping area, and as grazing
land for cattle.
SITE LOCATION & CONDITIONS
The Adam's Rib Recreational Area is in the northern part of Sawatch Range. This mountain range is an anticline complex or a large fold in the earth's crust. The orientation of this fold is northwest (Figure 1). The geology of the core of the Sawatch Range is composed of hard crystalline rock -Precambrian granities, gneisses, and migmatite. The flanks or sides of the range are composed of sediment type rocks -limestones, shales, and sandstones of Paleozoic and Mesazoic age. The vertical sequence of these rocks strata is shown in the geologic column (Figure 2). The region has been subjected to faulting and volcanic activity in Teriary time (up to 60 million years ago). The results of this activity have formed quartz monzonite plugs such as Porphyry Mountain and horizontal layers of volcanic rocks.
Faulting of limited extent is present in the area. The NW fault patterns appear to be related to extensions of the Rio Grande Rift zone which underlies the Arkansas Valley south of the study area.
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GEOLOGY OF THE HAT CREEK AREA
The Hat Creek drainage basin covers approximately square miles of moderately sloping (20 degrees) to steeply sloping (45 degrees) tree-covered terrain. This terrain is entirely underlain by the dark red siltstones, sandstones, and calystones of the dark red Maroon formation of Permo-Pennsylvanian age. Various slope deposits of Quaternary age cover this bedrock unit. These deposits include ancient landslides; more recent debris fans, alluvium, slump zones, areas in which creep is active, and colluvial deposits.
The Maroon formation (Cmr) is displaced by at least three faults in the Hat Creek area. The main fault follows the Hat Creek drainage from north to south, through a saddle just east of Picnic Point. This fault is downthrown on the west side.
The beds on the west side of the fault dip to the north and strike N 20 degrees E and dip 15 to 25 degrees northwest. Two more faults join the Hat Creek fault on its west side and coincide with drainages southwest across the ridge and down towards Sylvan Lake. These minor faults are located approximately. Quaternary Deposits
The Hat Creek area has six types of surficial deposits.
These include colluvium (1 to 10 feet thick), ancient landslides, slump zones, glacial moraines, dry wash deposits, and alluvium (stream bed).
The colluvium (Qc) that covers most of the area includes sandy, silty clays intermixed with gravel to cobble sized rock that vary in thickness from 1 to 10 feet. The average thickness is approximately 2\ feet. This type of deposit occurs on slopes less than 30 percent does not present a geologic hazard in the area. Colluvium on steeper slopes in ravines are sources of loose rock and soil for debris slides (Qd). Landslides (Qls)
Several ancient landslides occur in the study area.
These deposits appear to be related either to glacial activity of responses to nearby fault activity. They occur on slopes that exceed 30 degrees. The upper portions of slides are composed of scars that expose bedrock. The lower slump portion is characterized by irregular surfaces on the lower portions of the slide mass. These features and the irregular lobate outline of the disturbed slide mass can be detected on aerial photographs and on the maps. Most of the slides appear to be somewhat stabilized, consolidated, and are covered with dense stands of evergreens.
Slump Type Deposits
The slump areas are characterized by hummocky surfaces that form shallow, disturbed slope deposits. Soil masses are noticeable creeping downslope. Slopes are 25 to 35 degrees, contain dense
stands of evergreens, and usually face to the north. The lower soil horizons appear to contain greater quantities of water that contribute to the moderately unstable nature of slump deposits. The thickness of slump deposits is variable. An estimated maximum thickness is less than 20 feet.
Slopes with noticeable soil creep occur on the south side of Top Hat. There aspen and pine trees with diameters as large as 2 feet have trunks with curved bases that are offset. The roots may be uphill of the tree as much as 2 feet. Thicknesses of the soil creep masses are less than 5 feet.
Drywash Deposits (Qd and Qaf)
Drywash deposits occur in the Hat Creek area as debris fans caused by mud and rock flows during heavy runoff periods. These deposits are divided into two parts: debris slide areas (Qd) and debris fans (Qaf). The debris slide areas are composed of steep ravines that occupy the upper slopes at the study area. Topographic development of these ravines is usually well defined. The slope deposits that cover the catchment areas are composed of loose soils and weathered rock at least 1 foot thick. This upper feature represents the areas subject to rapid erosion and source areas of rock and soil.
The alluvial fans (Qaf) form the lowest portion of the drywash erosion features. These fans represent the areas of deposition or the limits of sediment accumulation as a result of
debris slides. This type of deposit often joins with similar adjacent deposits and coalesce to form the valley fill and mix with stream bed sands and gravels.
The debris fans (Qaf) are affected by minor slumping and soil creep. These drywash deposits consist of soft silts and clays mixed with sands and grade upward in size to slightly-rounded boulders. The fans form distinctive raised slopes on the alluvium and are easily seen from a distance and on topographic maps.
The valley-fill deposits occur downhill of active slump areas. Valley-fill deposits represent the coalescence of several drywash debris fans (Qaf) and form a linear feature in the lowest part of the drainage. High water tables and boggy ground may be present in the valley-fill deposit in the valley of Top Hat. The thickness of valley-fill deposits is variable. Alluvium (Qal)
The alluvial deposits within the study area are restricted to the main drainage of Hat Creek. The intermixing of alluvial sediments and slope deposits from the adjacent terrain is sufficient to cause the alluvium to be poorly defined in the upper reaches of the creek. The downstream portions of Hat Creek are wider (50 to 100 feet) than those upstream. Downstream, channel bed deposits are composed of red, rounded sands and gravels. The adjacent flood plain contains thick organic-rich loamy deposits 2 to 5 feet thick. The composition of the alluvium
changes to the north where the creek crosses the bouldery lateral moraine.
Above the intersection with the moraine, Hat Creek was dry at the time of this investigation October, 1971. However, below this point Hat Creek was flowing at discharges as much as 2 cfs.
Talus deposits are present in the study area Hat Creek and Adam's Rib Recreational Areas. These deposits form on very steep slopes (up to 45 degrees). Rock falls form on near vertical slopes. Both types form on non-vegetated and exposed bedrock outcrops in the Maroon formation, the Morrison formation, the Dakota formation, and in the intrusive plug at Porphyry Mountain. Talus deposits are composed of large tubular to equi-dimensional-shaped angular rock fragments of all sizes from sand to large boulders without soil development. These deposits are at an equilibrium condition of stability. Talus deposits are not usually thick deposits (average 5-10 feet), Such deposits may be used as potential sources of rock for road beds and aggregate.
Rock falls occur only in areas where slopes are near vertical and greater than 45 degrees. These areas include the southwest flank of Mt. Eve, Mt. Adam, Porphyry Mountain, and the north rim of East Brush Creek valley.
The Hat Creek study area does not contain ground susceptible to subsidence and related effects. Subsidence is a process caused by downward displacement of surface materials. This process can be initiated by:
a) removal of large volumes of ground water
b) hydro-compaction of light weight and dry silty soils, i.e. windblown loess or silt fractions of alluvial fans.
c) dissolution of portions of rock or soil that contain water soluable minerals such as gypsum
or halite (salt) and to a lessor extent limestone
d) removal of support by underground mining
The study area does not contain any such features. Areas to the west and south are underlain by the Minturn (Eagle Valley Evaporite) formation which contains gypsum. These water soluable gypsum bearing strata are affected locally by ground water. The Minturn formation also contains many dolomite and limestone beds, which are water soluble but to a much less degree than gypsum bearing beds. Although the Minturn formation underlies portions of the Hat Creek area, this formation is covered by at least 1000 feet of Maroon formation siltstones and conglomerates which are not susceptible to subsidence.
Expansive soils contain clays that expand upon wetting and shrink when dry. Volume changes as much as 15 percent may affect foundations of structures if properly designed foundations are not incorporated. Such an extreme condition is not present in the Hat Creek study area. Some surficial materials that are weathered products derived from the Maroon formation contain slightly expansive clays. These clayey soils, however, should not present foundation problems. Investigation of individual sites should include special tests to confirm this general observation.
Colorado is in a region of historically low seismic activity.
Nearby areas, such as Glenwood Springs, Aspen and Baxter Mountain have been subjected to low-energy earthquake activity (2.5 to 4.0 M) within the last 100 years (Hadsell, 1968).
Evidence of recent faulting was not observed in the Adam's Rib Recreational Area.
An estimated average energy value which could be expected to be generated by an earthquake within a 200-mile radius of the Adam's Rib Recreational Area is 5.5 Magnitude (Richter Scale). This value is a typical of earthquake activity in the Rocky Mountain Plateau Province (Iladsell, 1968) Estimates of fault activity are based on a 100-year period of record.
Frequency of earthquake events is very difficult to estimate because of the short historical record of 100 years. The largest earthquake (estimated at 6.7 M) in the Rocky Mountain Region occurred in 1887, just north of Denver. This earthquake was felt in Leadville, Pueblo, and Cheyenne (Hadsell, 1968). To estimate when and where such an earthquake may occur again is not within the realm of present technology.
The study area does not contain unusually high concentrations of radioactivity. There are no known natural sources or radioactivity other than a normal background radioactivity typical of the region. There are no known radioactive mines, mine waste dumps, mill tailing piles, or other radioactive waste disposal sites in the immediate vicinity of the study area.
Nearby geologic formations which contain very low levels of radioactivity are the Morrison and Dakota formations which outcrop north of the study area. The large quartz monzonite intrusive that forms Porphyry Mountain and the Precambrian rocks south of the study area may also contain some background radioactivity. There are no known uranium prospects in these nearby formations. Assays of ore samples from the Brush Creek Mining District north of the study area did show low concentrations of uranium (Vanderwilt, 1947).
ADDITIONAL GEOLOGIC OBSERVATIONS
The geology of the main portion of the Adam's Rib Recreational Area has been field checked as part of this reconnaissance investigation. The suggested revisions that have been made as a result of this field check are as follows:
1. Adam's Bowl Area Evidence of several landslides and large slump complexes were observed. This evidence includes scars that expose bedrock siltstone, slope angles exceeding 40 degrees, trees severely curved downhill, large step-like hummocky terrain affected by dislocation of slump blocks, and raised lobate deposits of drywash materials downhill of the disturbed slope features observed above. The extent of these features can be seen on aerial photographs and to limited extent on topographic maps. Recent slump activity was not observed.
2. Fisher Gulch Area Here also is evidence of a large landslide-slump complex. This complex contains dense stands of evergreens and aspen where the ground is moist to very moist. The step-like benches typical of slump affected terrain were also observed, but recent slump activity was not.
3. Lower Hat Creek Area Previously this area was mapped as moraine (Qm). Closer examination reveals that the
moraine is restricted to the south side of the creek bed. Occasionally one sees rounded cobbles and boulders on the lower third of the slopes of the north side; however, colluvium and bedrock outcrop are the predominent features. Also not previously mapped is a fault that is oriented north-south and forms a distinct fault-like scarp adjacent to the Maroon formation-moraine contact. The fault-like scarp (NW% of the NW% of Section 27) is expressed as a tree-covered cliff 60 feet high. Bedding on the west side is oriented north and dips 20 degrees W.; bedding on the east side is oriented N 48 degrees E and dips 45 degrees N. The fault line scarp extends north as a low depression toward No Name Creek. The southward extension of this fault is in line with Hat Creek. Jo Goode Meadow Area Previously the area south of Jo Goode Meadow, in Section 23. was mapped entirely as moraine. The main ridge however, is composed of bedrock siltstones. Also, glacial outwash gravel deposits make up most of the Jo Goode Meadow area.
The meadow was probably formed as a result of either a sudden flood caused by a breach in a natural dam formed by one of the last moraines to be deposited in the area or from continual stream flow from glaciers.
5. East Brush Creek Several large ancient landslide deposits were observed above the south bank of East Brush Creek in Sections 16, 17, and 18. The scars on the upper slopes and slump block on the lower portion of the slope form this deposit. Bedrock siltstones dip downhill 30 degrees N and the beds strike N 70 degrees W. The average slopes in this area are 30 degrees to 45 degrees. Recent movement of these features was not observed.
The conclusions of this reconnaissance geological engineering investigation of the Hat Creek and Adam's Rib Recreational areas is as follows:
1. The Hat Creek area is suitable for development of a ski-recreation area.
2. The area is entirely underlain by the red-to-ark brown colored siltstones and sandstones of of the Maroon formation.
3. A major fault, oriented north-south, appears to follow Hat Creek south from No Name Creek. The fault is downthrown on the west side.
4. Other faults are present in the Hat Creek area. Locations where these faults intersect the Hat Creek fault may yield substantial quantities of ground water.
5. Surficial geologic features include colluvium, ancient landslide deposits, recent slump zones, moraine deposits, outwash debris fan deposits and alluvium. The predominent surficial deposit is the thin veneer of stable colluvium.
The areas of most severe potential hazards in the Hat Creek area are steep, tree-shaded slopes. These slopes contain dense growths of evergreens
and generally face north. The slopes contain slumps which appear to be shallow, usually within 20 feet of bedrock.
7. Although the area contains slope failure deposits, numerous roads 20 to 50 years old criss-cross the area and are accessible to 4-wheel vehicles. The execellent condition of these roads indicates that similar type roads could be built in other parts of the
area with a minimum impact on the slope stability.
8. The geotechnical condition of the area in the vicinity of the proposed gondola structure in Hat Creek appears to be adequate for the foundation
of this large structure.
9. Foundations for most of the proposed ski tows should be located to avoid slump areas.
10. Temporary roads may be designed across the Adam's Bowl areas.
11. The foundations of the proposed gondola structures and related support facilities may be adequately designed and incorporated into the existing
site conditions in the Adam's Rib Recreational areas.
12. The Hat Creek area does not contain any radio-
active or metallic mineral resources and does not
contain potential sand and gravel deposits.
13. Subsidence and expansive soils features are not present in the Hat Creek area.
14. Seismic effects caused by earthquakes may occur within a 200 mile radius of the study area. The 100-year historical record indicates potential release of energy of 5.5 M on the Richter scale.
The recommendations of this report are as follows:
1. The proposed development of the Hat Creek area should proceed for use as a recreation site.
2. The sites for the gondola and lifts should be investigated in more detail to provide structural engineer data sufficient for subsurface design.
3. The sites for the lift houses, transit and cable support towers should be investigated and located to avoid hazardous geological features and foundation conditions.
4. Major structures should not be placed at stream grades in Hat Creek but may be elevated and protected by carefully designed plans.
5. Existing roads should be utilized as much as is practical; however, temporary roads can be designed as required.
6. New unpaved roads and existing unpaved roads should incorporate drainage control structures such as culverts, headwalls, and erosion diversion berms.
7. Hat Creek fault should be investigated as a source for water.
8. Foundation conditions in East Brush Creek Valley and in
Jo Goode Meadow will require further evaluation especially for large structures and for structures subject to vibration
SOILS EXISTING CONDITIONS
Geomorphic features of the study area that are important in determining soil parent material and soil processes include moraines, colluvial slopes, valley bottom alluvium, and high elevation ridges and saddles.
Moraines in the study area have been mapped as Early Pinedale in age by Miller (1971). Most of the morainal material is present in lateral moraines along East Brush Creek (Adams's Rib is itself a lateral moraine). End moraines are found below Vassar Meadow and Yeoman Park. The material in the moraines is a variable mix of sedimentary and crystalline rock eroded from outcrops of Maroon formation and from higher plutonic peaks at the head of East Brush and Nolan creeks.
Colluvium covers the slopes steeper than 10 degrees in most parts of the study area. This colluvium is mostly derived from Maroon formation sandstones and siltstones, although the slopes above and northwest of Jo Goode Meadow are composed primarily of colluvium from the Tertiary intrusive rock of Porphyry Mountain. Maroon formation colluvium is variable in nature: dn Adam Mountain it is composed of coarse sandstone fragments, on Mount Eve it is also coarse but apparently slightly less resistant to weathering, and in the Hat Creek drainage it is composed of smaller fragments
of siltstone and fine sandstone.
Alluvium comprises the parent material in the bottoms of most of the drainages; these deposits usually are stratified and often are sandy in texture. The material apparently has been moved to its present location as a result of stream action and surface erosion from adjacent slopes. Along the larger creeks (i.e., East Brush Creek and Hat Creek), the alluvial deposits often are raised above the level of the stream by as much as 2-3 m into low terraces.
On higher elevation ridges and saddles, fine material is moved downslope by surface erosion and mass wasting, but none is supplied from above. Thus, unconsolidated material at these locations usually is relatively thin and is composed of material produced by weathering of bedrock, in situ.
Small to medium size terraces occur on the north slopes of Adam Mountain and Mount Eve, where the surface is more or less parallel to the dip of the underlying Maroon formation strata.
These are the product of previous slope instability which apparently is not now active. The effect of these surface features on the soils is minor.
Overview of Physical and Chemical Characteristics
Results of this study reveal that soils of the Adam's Rib area
are predominantly of moderate texture, mostly sandy loam, loam, and silt loam. Extremes of texture, such as sands or clays, were not found in horizons near the surface. Loams and silt loams tend to be found in soils derived from Maroon formation parent material, while sandy loams tend to be present on morainial and alluvial parent material.
As with most mountain soils, nitrate nitrogen and phosphorous are low enough that they limit plant vigor (in that an application of N and/or P would probably elicit increased herbage production). Phosphorous tends to be relatively low in soils under conifers on Maroon formation parent material, while soils on Maroon formation material under aspen are nitrogen poor and intermediate in phosphorous. On moraine beneath aspen, soils are relatively nitrogen rich and phosphorous poor. Soils developed on alluvium under grasses are intermediate in both nitrate nitrogen and phosphorous.
Soils under aspen tend to be neutral or slightly acid. Those under conifers at low and middle elevations (up to about 9,500 ft (2,896 m)) tend to be slightly acid. Soils under conifers at high elevations tend to be strongly to very stongly acid. Meadow soils tend to be moderately acid, while pasture meadow soils are
Erodibility of the soils in the study area was examined using procedures outlined by the U.S. Forest Service (1975).
The index resulting from this evaluation is based on the resistance of soil aggregates (soil structure units) to detachment or dispersion, the rockiness of the soil surface, and the permeability of the profile. The evaluation of soils in the study area is presented later in this report.
Soil erodibility in the study area generally is moderate. The major exceptions are the fine soils with structureless single grain surface horizons, such as the soils found in some of the high elevation ridge and saddle meadows and the soils beneath sagebrush and sparse oak stands in the lower elevations of the study area.
The erosion hazard indicated by these ratings is assessed without regard to slope or the ameliorating effects of the O-horizon (duff or litter layer) present at the surface of most of the forested soils.
The effects of slope on the inherent erosion hazard can be estimated by the following formula:
Erodibility Index + Topographic Hazard Inherent
2 = Erosion Hazard
where the Topographic Hazard is based on the following scale:
SLOPE GRADIENT (%) CLASS RATING
The resulting Inherent Erosion Hazard number can be judged
against the following scale:
5. High Unprotected bare soil will erode sufficiently to severely and permanently damage the production capacity of the soil or will yield excessively high volumes of sediment (assumes geologic significance).
4. Moderately High Unprotected bare soil will erode
sufficiently to severely damage productive capacity or will yield high volumes of sediment.
3. Moderate Sufficiently resistant to erosion to permit limited and temporary exposure of bare soil during development or use.
2. Moderately Low Sufficiently resistant to erosion to
permit exposure of bare soil under minimal precautionary restrictions.
1. Low No appreciable hazard of erosion.
Upon disturbance, the structure and permeability of some soils may change, thus changing the erodibility characteristics. Therefore, the erodibilities and inherent erosion potentials discussed above are of limited utility when the soils are disturbed. The most useful conclusion to be made concerning these mountain soils probably is that the accompanying steep slopes, weak development, and/or concentrated water flow can result in the erosion of any of the soils of the site.
Thus, attention should consistently be given to erosion control or protection measures during planning and construction of any facility.
Soil Features Most Sensitive to Disturbance
In general, the greatest changes to soils resulting from disturbance are the loss of fertility and/or the loss of the soil through erosion or burial. Loss of fertility could result from mixing soil with sterile geologic material through mass wasting processes. Fertility loss could also occur if upper horizons are partly or completely lost through erosion during an interval when the vegetation has been removed.
The most extensive soils of the site have rather thin A-horizons, and the loss of A-horizon material is thus more likely to be significant. If a large portion of the A-horizon were lost, these soils would be less productive and would support a sparser
vegetational cover, providing a less effective stabilization of the remaining soil. Soil development is a slow process, and lost soil will not be replaced within the reasonable future (the period of development required is on the order of thousands of years).
Loss of topsoil by burial or mixing with sterile material likewise is a potential threat to the soils of the site during development and operation. Care should be taken throughout to remove and preserve topsoil. A particularly valuable soil resource occurs under the Pasture Meadow vegetation type. The A-horizon is these soils is 50-100 cm which is considerably thicker than other well drained soils of the site. Since these well drained soils are likely locations for development, it is important to plan to preserve them for use in locations where suitable topsoil currently is scarce.
VEGETATION EXISTING CONDITIONS
The greatest portion of the study area is vegetated by forest, most of which can be classified as Evergreen (Non-giant) temperate coniferous forest. There are also large areas of cold deciduous forest with, and without Evergreen trees. Temperate cold deciduous thickets occur along much of East Brush Creek through the study area.
There are no plant species thought to exist in the study area that are declared, or proposed as threatened or endangered by the U.S. Fish and Wildlife Service. However, there are a few species considered "rare".
From the standpoint of identifying the areas which would take the longest to recover their biological character due to disturbance, the following rating of sensitivities can be
High (longest time to regenerate to current condition) Spruce-Fir-Valley Bottom along Hat Creek; High Elevation Meadow
Moderately High Aspen on slopes and in Valley Bottoms on Adam Mountain; Riparian Forest and Shrub; Scattered Spruce-Fir; Mesic Mountain Meadow; Wet Meadow
Moderate Aspen in East Brush Creek Valley Bottom; Spruce-Fir-Upland; Spruce-Fir/Lodgepole Pine; Riparian Spruce and Lodgepole Pine; Willow; Alder
Moderately Low Lodgepole Pine, Mesic Mountain Shrub; Dry Mountain Shrub; Sagebrush; Shrubby Cinquefoil
Low (shortest time to regenerate to current condition) Pasture Meadow; Logged areas; Rockfall areas
Spruce-fir forest is the climatic climax of most of the study area. This means that under moderate (i.e., non-extreme) conditions of soil and exposure, spruce-fir forest would develop, given a long enough period without disturbance and assuming that present climatic conditions continue. While a large part of the study area is covered by spruce-fir forest, most is rather immature, and the only stands which exhibit mature stand character are found along drainage channels in the Hat Creek area. In addition, the areas now occupied by Lodgepole Pine are proceeding toward spruce-fir dominance within the next few hundred years.
The spruce-fir forest is a persisting type because both spruce and fir can reproduce in shade. No other potentially dominant woody plants are naturally present which could push spruce and fir from dominance without interference from some outside factor, such as fire or insect epidemic.
Areas mapped as scattered spruce-fir have developed on rock fall areas. These areas are usually of rather low slope compared with most rock fall areas. The development of trees on these sites is very slow because of limited deposits of fine material among the rocks and because of severe atmospheric conditions at
these sites near the summit of Adam Mountain. The trend is toward a more complete cover of spruce and fir, but forest expansion is slow. The scattered nature of the trees in these areas does not reflect thinning by fire as might be supposed from a distance, but rather reflects a substrate limitation.
Lodgepole Pine Stand-types
Within the study area, all Lodgepole Pine stands are ultimately successional to spruce-fir. Occasionally, stands of Lodgepole Pine have been identified in Colorado and Wyoming which are apparently self-perpetuating, but these have a well-developed multi-aged structure demonstrating a pattern of selfperpetuation Stands within the study area lack this structure, having basically one age class, as is typical of Lodgepole Pine stands which develop following a fire. Charred snags in most stands provide clean evidence of past fires. Many of the Lodgepole Pine stands are approaching "stagnation" (i.e., the stage where intense competition between crowed stems has resulted in a stalemate). The forest at this point consists of crowded, leggy, struggling trees.
As previously mentioned, some of the Aspen stands are apparently successional to spruce-fir (successional Aspen stand-type), while others are apparently persistent (stable Aspen stand-type)
Some stands may have an intermediate phase of Lodgepole Pine before ultimate dominance by spruce and fir.
The trend toward the replacement of aspen by spruce, fir, or lodgepole is clear in the successional Aspen stands, where large conifers are present. Nevertheless, the rate of succession in these stands is slow. The rate of succession in Stable Aspen stands is imperceptible and, as a practical matter, these stands are climax stands, under current climatic conditions.
As with riparian forest and shrub stands, willow stands seem stable in their poorly drained soils. No trend toward a shift in dominance among the woody species is observable. The understory has been heavily used by cattle, and many of the mesic forbs and perhaps some grasses have disappeared or have become restricted to the interior of willow thickets where cattle cannot penetrate. Agassiz (Kentucky) Bluegrass and Red Top have replaced the taller species once present in most of the understory.
Willow stands are dependent on moist soils with the water table located a short distance below the surface. If water tables should rise to the surface, insufficient soil aeration would probably result, and the willows would suffer. If water tables dropped, there might not be a dramatic effect on established willows, as they could find adequate moisture without having
saturated soil available. Over the long term, however, stand replacement would decline, and the stands would slowly shrink.
It is apparent that the moisture in the willow stand soils derives not only from the streams but also from goundwater draining from adjacent slopes. The relative importance of the two sources is likely to vary in proportion to distance from a stream. Consequently, interfering with stream flow or groundwater flow would affect different areas of willows.
If grazing were to cease in willow stands, a slow recovery of mesic forbs and grasses would occur, although the Bluegrass and Red Top would probably provide strong competition initially. Return of the natural understory would doubtless have some effect on small wildlife in these stands, mostly an enhancement due to increased cover and seed production.
Wet Meadow Stand-type
Wet Meadow stands occur in sites where soils are saturated permanently and drainage is very slow, leading to a "stagnation" of the water and, frequently, anaerobic soil conditions. Often, areas of this sort occur as an advanced stage in hydrosere succession as discussed below. The dominance in these areas lies with sedges, which apparently are adapted to the conditions of poor soil aeration. These stands are highly dependent on not only high water table but slow water flow. If the water table
were altered slightly, wet meadow stands probably would be more severely affected than willow stands would. Lowered water table probably would result in an eventual invasion by willows or, perhaps, Bog Birch.
In general, animals are sensitive to any adverse alterations in their environment -- particularly as they affect factors such as reduced availability of winter browse, disturbance during calving or fawning, and interference with access to water. In the Adam's Rib area, wildlife can be expected to be sensitive to two general groups of environmental stress: habitat reduction and disturbance.
Any development necessarily alters existing habitats, by eliminating some natural areas (which are replaced with buildings, parking lots, roads, recreation facilities, etc.) and by changing vegetational patterns in others (e,g., clearing trees for a grassy ski slope, replacing native plants with landscape species, etc.). Naturally, the severity of the impact of all habitat modifications -- and the sensitivity of wildlife to those modifications -- is related primarily to the criticalness of the habitat, either to a species in particular or to the ecosystem as a whole.
Reptiles, amphibians, small mammals (especially shrews and small rodents), and small birds (to a lesser extents, because of their increased mobility) are sensitive to reduction of the particular habitats where they breed and feed. Because of their rather
limited home ranges and smaller requirements, these small animals are vulnerable to small scale ecological changes.
Generally, a given habitat is essentially fully occupied (utilized) by birds, small mammals and herptiles; thus, a 50 percent reduction in suitable habitat leads to at least a 50 percent reduction in population size. This habitat reduction need not represent an elimination of one-half the total area, but may instead represent a diminution of one-half of the available food, nesting sites, and so forth. The reduction in population size may be greater than the amount of habitat loss if, for example, a threshold area or quality is necessary for utilization of that habitat.
Larger, more mobile species, such as carnivores and big game, differ from smaller species in that they generally cannot meet the quantity or quality of their ecological needs within any one habitat or habitat type. Therefore, these species are sensitive to destruction or alteration of any part of their ecological ranges, even though most of the area may not be affected. For example, deer would be adversely impacted by the loss of winter browse, even if summer browse, cover, and water were still available. Similarly, predators would be negatively affected by reduction in prey species resulting from loss of herb or shrub species, even if the area were to remain intact otherwise.
Each of the four principal wildlife habitat types in the Adam's Rib area -- coniferous forest (including meadows and slash), aspen woodland, mixed shrub, and riparian -- would be affected to some degree by the proposed development. Of these, the latter two habitat types are the most sensitive to disturbance and are the most "important" (either by virture of their significance to wildlife or their limited areal extent). The first two types are more widespread, are perhaps less critical to the total ecosystem (because they are so widespread), and/or are less likely to be severely reduced or altered.
Riparian areas, particularly those dominated by willow thickets, are both vulnerable to modification and critical to a number of wildlife species. They are vulnerable because their existence is dependent on the maintenance of adequate soil moisture -- a rather precarious balance between being too dry and too wet.
While the willows are adapted to fluctuations in soil moisture, these changes need to be regular and without prolonged extremes of either dryness or wetness.
Willow thickets are critical to the population of a number of songbirds which do not occur elsewhere in the area. The importance of willows is a function of the numerous nesting sites, food, and foraging areas which they provide these primarily insectivorous, arboreal bird species.
While not particularly sensitive to disturbance itself, the mountain shrub habitat appears to be the most critical to big game. Mixed shrubs provide abundant browse throughout the year but are especially important by providing food in the winter.
The importance on the mountain shrub communities results from:
(1) the fact that shrub twigs, buds, and fruit are palatable and nutritious during the winter, and (2) their occurrence on south-facing slopes, which are warmer and hence both more comfortable and relatively free of snow. The largest and most important area of mixed shrubs in the Adam's Rib study site occurs along the lower portion of the East Brush Creek. However this area is designated as critical deer and elk winter range by DOW and is not in an area for which development is planned.
Development within conifer and aspen woodlands is expected to be limited primarily to the construction of ski slopes and lifts Although ski slopes represent the largest extent of habitat alteration for the proposed development, their construction cannot be viewed as an overall adverse impact, since (1) the conifer and aspen woodland types are the most widespread in the area, (2) many conifer stands (particularly Lodgepole Pine) are only lightly used by wildlife, and (3) the creation of numerous edges (ecotones) -- with resultant increases in compositional and structural diversity -- and the establishment of
"meadows" (if revegetated properly) are expected to enhance rather than diminish those areas for a variety of wildlife, including big game.
A type of habitat reduction results from heavy use by domestic grazers. At present, many areas, particularly meadows and open aspen stands, are grazed by cattle during the summer, which reduces food available to wild herbivores throughout the year. A positive benefit of the proposed development is that cattle will be withdrawn from the area, thereby increasing the quality of natural habitats not otherwise affected. Habitat reduction can be mitigated by avoiding or reclaiming sensitive areas and/or by improving habitat in other, undisturbed areas.
In addition to reducing or altering habitat, any large development is also likely to affect the animal community through direct or indirect disturbance associated with human habitation or other activities.
One of the most important problems associated with increased frequency and intensity of human/wildlife interactions is the definite but difficult-to-quantify furtiveness of some species. That is, many animals simply are intolerant of the presence of significant numbers of human beings. This seems to be especially
true for most carnivores (both avian and mammalian), for many small species, and for big game.
The response of wildlife to human occupation varies between individuals and among species. For example, elk generally are more wary than deer of human beings and are also slower to habituate (acclimate). In fact, deer seem to adapt readily to the presence of human beings if (1) food is available, (2) buildings are interspersed with natural areas, and (3) harassment and hunting are eliminated (or at least restricted). Elk generally do not habituate as readily to human disturbance but may be tollerant of road traffic, as long as they are not harassed (Schultz and Barley 1978). Elk and deer are especially sensitive to disturbance during the breeding and fawning or calving seasons when the availability of necessary cover in undisturbed areas may be limited.
A more quantifiable adverse effect of mountain development is the possible increase in collisions between automobiles and big game, usually associated both with heavier traffic and (as a result of upgraded roads) higher speeds. Information available at present suggests that deer cross the East Brush Creek Road seasonally, while moving between summer range and winter range, and daily, to obtain water from the creek. Deer and elk road crossings may, in some areas, be restricted by fences, underpasses,
and habitat manipulation along roadsides. These techniques, used in various combinations, have been effective in reducing deer-auto collisions along some Colorado highways.
Another direct effect on wildlife of a large development is invasion of wildlife areas by hikers, campers, cross-country skiers, snowshoers, snowmobilers, or 4-wheel drive enthusiasts.
As noted above, big game are especially sensitive to human disturbance during calving, fawning, and the rut, but excessively heavy use could be detrimental in any season. This can be controlled by designating critical areas as "off-limits" to back country use during certain times of the year. People tend to (and should) follow established trails, which could easily be located so as to avoid critical areas.
Perhaps the most serious disturbance of big game (and mammals in general) associated with humans is the seemingly inevitable carnivorous pet (dogs and cats). If allowed to run loose, dogs form loose packs and chase big game for miles. Although healthy game generally are not caught or injured by dogs, the animals are subjected to stress and, if they must run through deep snow, fatigued. Either may be physically debilitating. Furthermore, behavioral patterns, especially during social interactions such as sparring, bouting, herding, mating, and fawning/calving, may be disrupted. Pregnant females are especially vulnerable, both
because they are more easily caught and are apt to suffer a spontaneous miscarriage. Young game animals are vulnerable to predation by dogs. Cats are an equally serious (or greater) problem for small mammals, such as chipmunks, ground squirrels, and birds.
Animals occurring naturally in the Adam's Rib area are sensitive primarily to habitat reduction and direct disturbances, both of which are inevitable but not completely uncontrollable consequences of mountain developments.
Most wild animals show an ability to habituate to human presence, at least to some extent if forage and cover are provided and if harassment, particularly by domestic predators, is controlled. To this extent, mountainous area development can be designed and constructed in such a way as to either minimize adverse impacts or mitigate them by improving habitat in other ways. To do this successfully, it is necessary to recognize the inherent sensitivities of certain species and habitats, to respect their intrinsic value, and to provide for their ecological needs or behavioral quirks throughout the development, from construction through ongoing operation.
The study area is located approximately 10 miles south of Eagle, Colorado. The proposed ski area portion of the develop ment is to occur chiefly within the East Brush Creek drainage, but the study area also included sampling sites on West Brush Creek below the confluence of the east and west forks. These waters are cold, clear, fast-flowing mountain streams, with good water quality.
PHYSICAL HABITAT East Brush Creek
East Brush Creek is composed of two physically different stretches. The upper portion, extending through Yeoman Park to the Vassar Cabin culvert, meanders through a broad, glacial meadow. Average stream gradient in this stretch is 150 feet per mile. Stream substrates in this section consist of sand, gravel and rubble, with only a few large boulders. A number of active and old beaver ponds are important in this section because they provide a series of impoundments which have increased the available trout habitat and serve as settling areas for silt and organic detritus which might otherwise smother developing trout eggs.
Within this section, shallow, fast-flowing riffles provide good production areas for benthic invertebrates and ideal spawning areas for trout. Deep pools and numerous undercut banks provide
essential shelter, resting, feeding, post-hatching, and overwintering areas.
Little plant material is produced within any of the area's streams; rather, externally produced organic material supplies most of the energy and nutrients. This allochthanous material is produced by dense stands of willows and grasses which anchor and stabilize stream banks and provide additional shelter. In addition, terrestrial insects, dislodged from streamside vegetation, provide significant portions of the daily diet to trout inhabiting this area.
Below the Homestead Cabin, East Brush Creek meanders through an area abundant in streamside vegetation (primarily willows). This area is also typified by a series of pools, and undercut banks and riffles, which provide good fish habitat. Cattle grazing within the area rely upon this creek for water and have destroyed many over-hanging banks and keep portions of the stream heavily silted at cattle crossings.
The lower portions of East Brush Creek drops tumultuosly through a boulder-lined channel. Gradients within this lower four miles of East Brush Creek vary from 450 to 550 feet per mile. Deep plunge pools, undercut banks, caverns in old beaver dams, and quiet areas around large boulders provide excellant trout habitat. Depth of these pools allows overwintering throughout the stretch;
however, few riffles exist within this stretch of stream due to the steep gradient.
Streambank vegetation within this stretch of stream consists primarily of thinleaf alders, willows, and aspen, and provide much of this area's allochthonous food and nutrient supply. Because of the rapidly flowing waters, most of the detritial food fraction is contained in deep pools.
The climate of the study area can be characterized as Cold Continental. There are no long-term records of precipitation in the study area, but the lower elevations apparently receive an average of about 25 inches (635 mm) per year and the higher elevations perhaps as much as 35 inches (889 mm) or more. Much of the precipitation occurs during the winter, with summer precipitation generally occurring in intense, short duration thunderstorms. In the modified Koppen notation, the climate of the lowest elevations is Dfb (Humid Microthermal, no dry season, mean temperature of coldest month 32 degrees F (0 degrees C) or below, cool summer, mean temperature of warmest month 71.6 degrees F (22 degrees C) or less) while the middle and highest elevations are Dfc (Humid Microthermal, no dry season, mean temperatures of the coldest month 32 degrees F or below, cool short summer, less than four months with mean temperatures averaging over 50 degrees F (10 degrees C)).
Eagle is located in the valley of the Eagle River in the mountains of central Colorado. The climate is characterized by low relative humidity, light winds, light precipitation, and large diurnal and seasonal temperature variations. The average monthly temperature varies from 18.1 F in January to 66.1 F in July. The diurnal temperature range (difference between the daily maximum and minimum temperatures) is very large and often exceeds 40 degrees. Afternoon temperatures in the low 90's are not unusual during the summer months, but nighttime temperatures are always cool, usually dropping into the 401s. During the winter, temperatures below zero occur frequently as cold air settles into the valley.
Annual precipitation in the valley bottom near Eagle averages only about 10 inches, but precipitation increases rapidly as you move to higher elevations in the nearby mountains. Precipitation is distributed fairly evenly throughout the year. Light afternoon thundershowers account for the summer precipitation, while most winter precipitation falls as snow. Annual snowfall averages 48 inches near Eagle but increases rapidly with elevation. December and January are typically the snowiest months and snowcover often presists throught the mid-winter months.
SUMMARY OF MONTHLY CLIMATIC DATA FDR EAGLE F A A A?
FOR YEARS 1942-1979
SUBSTATION NO. 52454 DIVISION
LATITUDE 39 39 LONGITUDE 105 55 ELEVATION - 6500 FEET
40VTHLY MEAN MAXIMJM TEMP (F)
YEARS OF RECORD
MONTHLY MEAN MINIMUM TEMP (F)
AVE. MAX. YEAR MIN. YEAR
YEARS OF RECORD
MDNTHLY MEAN AVERAGE TEMP (F)
YEARS OF RECORD
APR MAY JJN JUL AUG SEP OCT
58.2 69.3 79.4 86.1 83.2 76.2 64.7
S7.2 75.3 86.5 89.5 87.9 82.6 73.6 1950
19 4 3 1969 1977 1963 1958 1956
51.6 63.1 72.S 82.6 77.8 66.0 51.0
1970 1957 1947 1973 1968 1961 1969
37. 37. 37. 37. 37. 37. 37.
25.2 32.7 38.7 45.4 43.8 34.6 25.0
29.2 1973 36.5 1947 43,0 1977 49.8 1977 49,3 1963 39.6 1947 33.4 1972
18.4 29.1 34.0 40.8 37.2 26.0 17.5
1945 1950 1944 1944 1950 1944 1952
37. 37. 37. 37. 37. 37. 37.
59. 1 64.9 197 7
DEGREE DAYS (BASE 65F)
AVE. 1443.8 1156.1 1007.7
MAX. 1680 1441 1311
YEAR 1979 1952 1952
MIN. 1181 927 794
YEAR 1956 1963 1972
YEARS OF RECORD 29. 29. 29.
NO DAYS MAX TEMP GTR OR EO 90F AVE. 0.0 0.0 0.0
YEAR 1948 1943 1948
YEAR 1 9 79m- 1979+ 19797-
YEARS OF RECORD 31. 31. 31.
NO DAYS MAX TEMP LESS OR ED 32F AVE. 12.9 5.9 2.1
MAX. 24 14 8
YEAR 1979 1955 1952
MIN. 1 0 0
YEAR 19547- 19 7 5 + 1979 +
YEARS OF RECORD 32. 32. 32.
35.4 47.5 55.2 62.8 60.2 50.2
1945 1953 1945 1944 1950 1961
37. 37. 37. 37. 37. 37.
595,7 8 5 7 423,3 5?7 167 1 2 & 5 24,2 &2 67,1 1 5 5 28 3,1 438
1970 1953 1951 1973 1968 1961
578 277 34 1 2 157
1954 1969 1977 1966 1969 1963
29. 29. 29. 29. 29. 29.
23.3 1 978 +
1956 + 22.8 1956 38.
1 94 7 7
1 979 + 31.
1973 + 0
1979 + 31.
1956 + 0
1979 + 31.
197 6 + 31 .
1969 + 32.
1979 + 31.
1966 + 1
1967 + 32.
1979 + 31.
3.9 1 4
1978 + 32.
1979 + 31.
1975 + 32.
1979 + 31.
618.8 1022.4 1414.0 8328.5 9331
811 1260 1 6b 2
1969 1956 1954 1952
446 357 1139 7394
1963 1956 1977 1977
29. 29. 29. 29.
0.0 0.0 0.0 15.8
0 0 0 35
1943 1948 194b 1954
0 0 0 2
1979 + 1979 + 1979 + 1967
31. 31. 31. 31.
1979 + 0
HIGHEST TEMPERATURE (F)
IS OR ED 32F AVE. 30.8 28.1 30,3 26.5 15.3 3.4 .2 .8 11.3 26,2 23.4 30.7 232.9
MAX. 31 29 31 30 23 1 2 2 5 20 31 30 31 251
YEAR 1979 + 1972 + 1977 + 1966 1950 195 0 1955 1962 1951 1952 1979 + 1979 + 1950
MIN. 29 27 26 23 7 0 0 0 4 12 25 29 20b
YEAR 1972 1973 + 1 9b7 1956 1969 1977 + 1979 + 1979 + 1977 + 1972 1965 1964 + 1972
YEARS OF RECORD 32. 32. 32. 32. 32. 32. 32. 32. 32. 32. 32. 32. 32.
iS OR ED 0 F AVE. 14.0 8.5 2.0 .1 0.0 0.0 0.0 0.0 0.0 0.0 2.8 12.6 40.4
MAX. 2 4 23 10 1 0 0 0 0 0 0 1 5 25 69
YEAR 1958 1964 1964 1973 + 1948 1943 1948 1948 1948 1948 1956 1954 1952
MIN. 3 0 0 0 0 0 0 0 0 0 0 2 1 7
YEAR 1956 1970 1978 + 1979 + 1979 + 1979 + 1979 + 1979 + 1979+ 1979 + 1978 + 1977 + 1970
YEARS OF RECORD 32. 32. 32. 31. 31. 31. 31. 31. 31. 31. 32. 32. 31.
fFl TEMP 58 62 71 30 90 99 98 95 93 B 4 73 53
YEAR AND DAY197131+197721 197829 196219+195631+195423 196420 197906+197805+197506 194411 197301
YEARS OF RECORD 37. 37. 36. 37. 37. 37. 37. 37. 3 7 . 37. 38, 38.
fFl TEMP -51 -46 -26 -15 11 23 29 26 14 2 -29 -33
YEAR AND DAY196312 195101 194811 194504 194810 195402+196801 194430 194426 197525 195227 19622b
YEARS DF RECORD 37. 37. 3b. 37. 37. 37. 37. 37. 37. V I 37. 38. 38.
PREPARED BY : COLORADO CLIMATE CENTER
DEPARMENT OF ATM0SPER1C SCIENCE COLORADO STATE UNIVERSITY FORI COLLINS, CO 80523 nnn aoi asms
SJMMARY OF MONTHLY CLIMATIC DATA FDR EAGLE F A A A? COLORADO FOR YEARS 1942-1979 SUBSTATION NO . 52454 DIVISION 2
LATITUDE - 39 39 LDN GITUDE - 136 55 ELEVATION - 6500 1 FEET
JAN Fsa MAR APR MAY JJN JUL AUG SEP OCT NOV DEC ANN
MONTHLY PRECIPITATION (IN) AVE. .92 .50 .80 .87 .81 .95 1.00 1.02 1.02 .87 .66 .87 10.37
MAX. 2,88 1 36 2.06 2.28 2.72 2.55 2.45 2.64 4,68 1961 2.91 1.58 3.25 16.16
YEAR 19*9 1962 1975 1 357 1979 1943 1973 1952 1969 1955 1951 1957
MIN. .02 .38 .09 .08 .02 .31 1972? .17 0.00 0.00 .16 1 976 + .09 6.47
YEAR 1951 1973 196b 1967 1974 1968 1942 1944 + 1965 + 197b 1958
YEARS OF RECORD 37. 37. 36. 37. 38. 38. 38. 38. 38. 38. 38. 38. 36.
GREATEST DAILY PRECIP (IN) AMOUNT 1.23 .57 .77 .96 .96 1.12 1.26 .92 1.05 1,10 .97 1.31
YEAR AND DAY195129 195112 194928 195707 197907 195927 197529 196412 197219+195928 195429 195130
YEARS OF RECORD 32. 32. 32. 32. 32. 32. 32. 32. 32. 32. 32. 32.
MONTHLY SNOWFALL (IN) AYE. 11.5 6.3 7.0 3.9 1.1 .0 0.0 0.0 .4 1.7 5. b 10.2 48.4
MAX. 45.0 19.4 17.9 16.4 21.1 1.5 0.0 0.0 6.0 14.5 1969 15.0 4 7.7 93.0 1957
YEAR 1957 1956 1964 1957 1979 1976 1942 1942 1971 1954 1951
MIN. YEAR .2 1961 0.0 1954 0.0 1945 0.0 1976 + 0.0 197? + 0.0 1979 + 0.0 1979 + 0.0 197Â§ + 0.0 1979 + 0.0 1979 + 3.0 1949 . 9 1976 26.0 1963
YEARS OF RECORD 37. 35. 36. 37. 39. 3 B . 38. 38. 38. 38. 38. 38. 35.
GRTST DEPTH SNOW DN GRND IN MON (IN) 32 26 28 1 3 5 2 0 0 4 7 16 28
YEAR AND DAY195728 195701 195202+195201 197910 197614 0 0 197118 196930 195430 195131
YEARS OF RECORD 32. 33. 32. 21. 23. 32. 32. 32. 32. 25. 31. 32.
NO DAYS PRECIP GTR OR ED 0.1 IN AYE. 4.3 3.2 4.0 3.7 3.4 3.5 4.4 4.3 3.8 2.8 3.0 4.0 44.4
MAX- 1 5 12 13 13 12 16 11 17 11 9 10 1 2 109
YEAR 1950 1952 1952 1951 1953 1949 1950 + 1952 1950 1969 1948 1951 + 1949
MIN. D U 0 3 0 0 0 0 0 0 0 0 21
YEAR 1976 + 197 3* 1977* 1 977 + 1974 + 19 7 7 + 1972 + 1978 1979 + 1975 + 1976 + 197b 1958
YEARS OF RECORD 32. 32. 32. 32. 32. 32. 32. 32. 32. 32. 32. 32. 32.
NO DAYS PRECIP SIR OR ED 0.5 IN AVE. .4 .1 .1 .2 .3 .5 .4 .3 .5 .3 .2 .4 315
MAX. 2 1 1 2 2 5 3 2 3 2 1 3
YEAR 1 974* 1961 + 1948 1961 1979 + 1949 1948 1963 + 1971 + 1973 1965 + 1951 1948
MIN. 0 0 0 0 0 0 0 0 0 0 0 0 0
YEAR 1 978* 1979 + 1979 + 1 979 + 1978 + 1979 + 1979 + 1979 + 1979 + 1979 + 1 979 + 1979 + 1968 +
YEARS OF RECORD 31. 31. 31. 31. 31. 31. 31. 31. 31. 31. 31. 31 . 31.
NO DAYS PRECIP GTR OR EO 1.0 IN AVE. .3 0.0 0.0 0.0 0.0 .1 .1 0.0 .1 .0 3.0 . 1 .3
MAX . 1 0 0 0 0 1 1 0 1 1 0 1 2
YEAR 1951 1943 1948 1948 194 B 1959 + 1975 + 1948 1972 + 1959 1948 1966 + 1959 +
MIN. D 0 0 0 0 0 0 0 0 0 0 0 0
YEAR 1979* 1979 + 1979 + 1979 + 1979 + 1979 + 1979 + 1979 + 1979 + 1979 + 1979 + 1979 + 1979 +
YEARS OF RECORD 31. 31. 31. 31. 31. 31. 31. 31. 31. 31. 31. 31. 31.
NJM3ER OF DAYS WITH HAIL AYE. 0.0 0.0 .1 . 1 .1 .0 .1 .0 .2 0.0 3.0 0.0 .7
MAX. 0 0 3 1 1 1 1 1 2 0 0 0 4
YEAR 1956 1955 1973 1976 + 1979 + 1969 1963 + 1975 1977 1955 1956 195b 1973
MIN. 0 0 0 0 0 0 0 0 0 0 0 0 0
YEAR 1 979* 1979 + 1979 + 1979 + 1978 + 1979 + 1979 + 1979 + 1979 + 1979 + 1979 + 1979 + 1978 +
YEARS OF RECORD 23. 24. 24. 24. 24. 24. 24. 24. 24. 24. 24. 24. 23.
** NOTE t MANY WEATHER STATIONS DO NOT RECORD ALL HAIL OCCURRENCES. THEREFORE THESE DATA 1 MAY NOT B2l fcEPRESEMlATIVS.
NO. OF DAYS WITH SNOW ON GROUND AYE. 27.9 19.7 11.8 1.5 .3 .1 0.0 0.0 .1 1.1 5.5 21.1 90.0
CGTS OR ED 1 INCH ON GROUND) MAX. 31 29 31 5 4 1 0 0 1 5 1 6 31 1 39
YEAR 1 979* 1968 + 1964 1970 + 1979 1975 1963 1963 1971 + 1969 1954 1979 1964
MIN . 11 0 2 0 0 0 0 0 0 0 1 5 52
YEAR 1966 1973 1972 1978 + 1977 + 1979 + 1979 + 1979 + 1979 + 1979 + 1977 + 1976 197b
YEARS OF RECORD 17. 17. 17. 17. 17. 17. 17. 17. 17. 17. 17. 17. 17,
PREPARED BY 8 COLORADO CLIMATE CENTER
DEPARMENT OF ATMDSPERIC SCIENCE COLORADO STATE JNIVERSITY FORT COLLI MS, CO 8 0523 - (303) 491 6545
' ' Cv
ELEVATION 6497 FEET MSL LATITUDE 39 DEG 39 MIN LONGITUDE 106 DES 55 MIN
NO SOLAH RADIATION DATA AT THIS TIME.
LLIMATIC DATA All OATA COLLECTED AT EAGLE county AIRPORT. TEMPERATURE ANU PRECIPITATION AVERAGES ARE FOR THE 1951-1970 PERIOD. DEGREE DAY AVERAGES BASED ON 1941-1970 DATA.
SOLAR RADIATION JAN FEB MAP APH MAY JUN JUL AUG SEP OCT NOV DEC ANN RECORU (YtARb)
EXTREME MAXIMUM TEMP. (OEG F) 58.0 61.0 70.0 80.0 90.0 99.0 98.0 95.0 92.0 82.0 68.0 55.0 20
AVERAGE MAXIMUM TEMP, (DEG F) 34.0 39.2 46.1 57.6 69.8 79.8 86.5 83.2 76.1 64.4 47.0 34.8 20
MEAN TEMP. 18.1 23.4 31.3 41.* 51.3 59.3 66.1 63.8 55.3 44.6 30.6 19.1 *2.0 20
average minimum temp. 2.0 7.4 16.4 25.0 32.6 38.8 45.6 44.3 34.4 24.8 14.1 3.5 20
EXTREME MINIMUM TEMP. -51.0 -46.0 -20.0 -7.0 14.0 23.0 29.0 27.0 19.0 5.0 -29,0 -33.0 20
HEATING(65 DEG. BASE) 1457 1168 1051 693 425 190 43 79 285 626 1023 1386 8426 30
HEAT InG(60 DEG. BASE) 1302 1028 896 5*3 273 80 0 15 152 471 873 1231 6864 30
HEATINGI55 DEG. BASE) 11*7 888 741 393 138 17 0 0 62 320 723 1076 5505 30
C00LINGI6S DEG. BASE) 0 0 0 0 0 7 71 39 0 0 0 0 117 30
PRECIPITATION (INCHES) .80 .61 .76 .83 .80 .88 .99 1.19 1.11 .65 .77 .86 10.45 20
SNOWFALL (INCHES) 10.4 6.7 7.5 4.1 .5 0.0 0.0 0.0 .5 1.7 6.8 9.5 *7.7 20
Average Daily Solar Radiation Synthesized from Cloud Data
Averages based on 1952-1976 hourly cloud observations (Cinquemani et al, 1978).
kwh/m2/day and (BTU/ft2/day)
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANN
Colorado 2.81 3.71 4.89 6.09 6.71 7.47 6.97 6.38 5.55 4.28 2.98 2.47 5.03
Springs (891) (1178) (1550) (1931) (2129) (2369) (2212) (2025) (1759) (1359) (944) (782) (1594)
Denver 2.65 3.55 4.82 5.92 6.73 7.41 7.17 6.44 5.44 4.10 2.79 2.31 4.94
(840) (1127) (1530) (1879) (2135) (2351) (2273) (2044) (1727) (1301) (884) (732) (1568)
Eagl e 2.38 3.40 4.74 6.09 7.11 7.91 7.52 6.57 5.57 4.12 2.74 2.18 5.03
(754) (1078) (1502) (1933) (2255) (2509) (2385) (2084) (1767) (1307) (869) (691) (1 594)
Grand 2.49 3.53 4.90 6.26 7.50 8.19 7.77 6.88 5.78 4.24 2.89 2.30 5.23
Junction (791) (1119) (1554) (1986) (2380) (2599) (2465) (2182) (1834) (1345) (918) (731) (1659)
Pueblo 2.82 3.69 4.93 6.17 6.82 7.67 7.29 6.63 5.61 4.29 3.01 2.47 5.12
(894) (1172) (1564) (1956) (2163) (2434) (2312) (2102) (1780) (1361) (954) (782) (1623)
10 r 8 6 4
Figure 4. Average daily solar radiation and extremes (synthesized from cloud data), by month. Averages based on 1952-1976 hourly cloud observations.
EAGLE, COLORADO WIND SUMMARY
Summary period: January 1969 December 1973. Summary based on 14,608 observations, 8 observations per day at 3-hour intervals.
Location: Eagle County Airport located 5 miles W of Eagle on mesa 200 feet above river. Ground elevation 6497 feet.
Anemometer height: estimated at 50 feet (above ground)
Seasonal variations: No month by month summaries are available at this time. However, the dominant characteristic of wind in the Eagle area is the distinct diurnal variation of wind direction. At night the winds typically blow from the E (down the valley) while during the day W or SW winds prevail (up the Eagle River valley).
1-4 5-12 13-15 16-24 25 +
Annual Wind Rose
The site area commercial core will include a convention center, hotels, condominiums, commercial, retail, support facilities, and an underground parking garage. Information from the Eagle County Planning Office states that the 1979 Uniform Building Code (UBC) is to be used for building, and construction requirements. No other codes or restrictions are asked for.
Due to the complexity of the chosen project, there will be a combination of codes to use.
GROUP DESCRIPTION OF OCCUPANCY
A-2 Any building or portion of a building having an
assembly room with an occupant load of less than 1000, and a stage.
A-3 Any building or portion of a building having an
assembly room with an occupant load of less than 300 without a stage, not classed as a Group B, Division 2 occupancy.
B-2 Wholesale and retail stores, drinking and dining
establishments having an occupant load of less than 50, factories and workshops \asing material not highly flammable or combustible.
R-l Hotels, condominiums, apartment houses.
Researching the various facilities needed for a commercial core of the size and complexity proposed, I have listed those which would definately apply to the
BATHING COMPLEX INFORMATION CENTER
COFFEE SHOPS MAIN ENTRY
COIN-OP LAUNDRY MAINTENANCE
CONCESSIONS MECHANIC AI,
CONVENTION CENTER MONORAIL
DAY CARE CENTER PARKING
EMERGENCY TREATMENT RACKETBALL
EMPLOYEES AREA RESTAURANTS
EMPLOYEES LODGING SKI PATROL
EVENING DINING SKI RENTAL
FIRE DEPARTMENT SKI SCHOOL
FIRST AID SKI SHOPS
GIFT SHOP TENNIS COURTS
GUEST RECEPTION TICKET SALES
FUNCTIONS & SPATIAL
TOTAL GROSS AREA - 188,980 sq. ft
400 Guest Rooms = 144,000 sq. ft
Commercial 16,464 sq. ft
Services = 28,516 sq. ft
Will function smoothly and closely in the managment of the hotel. Natural light from the lobby area will be supplemented by artificial lighting, with climatic conditioning as needed. Some public control needed, especially to accounting, cashier, mail, etc. Safety codes will be followed as needed.
Registration, mail,keys, cashier Reservations/sales Bookeeping/accounting Manager
500 sq. ft. 200 sq. ft. 300 sq. ft. 200 sq. ft.
total = 1,200 sq. ft.
A "night life" atmosphere will incorporate prominent visual access from plaza, and hotel lobby. Main entrance shall be located near main circulation corridor between plaza and lobby. Will require controlled lighting and climatic conditioning (high ventilation requirements). All safety code regulations shall be followed.
Service area and dance floor
2300 sq. ft. 300 sq. ft. 150 sq. ft. 400 sq. ft. 200 sq. ft. total = 3350 sq. ft.
With a quiet, relaxed, subdued atmosphere, the lounge will have ease of access from the bar, and the restaurant with views to the lobby or plaza, or both. Will require controlled lighting and climatic conditioning as needed. All safety code regulations shall be followed.
Service area 700 sq. ft.
Preperation area 300 sq. ft.
Manager (from restaurant)
Toilets (shared with restaurant)
Janitor 36 sq. ft.
total = 1,036 sq. ft.
Will be used to serve the public when the restaurant is closed. Should have a light, clean atmosphere with quick service. Lighting to be natural and artificialy supplemented with ease of access to the public. Safety codes will be followed
Service area 1,400 sq. ft.
Kitchen 465 sq. ft.
Manager Toilets (shared with restaurant) Storage janitor (shared with restaurant) 150 sq. ft.
total = 2,015 sq. ft.
High visibility and access by the public will be
required. Natural lighting will be supplemented by artificial lighting for displays and merchandise. Climatic conditioning as required, and safety code regulations to be followed.
Retail areas (approximately 12 stores) 12 ,000 sq. ft.
Storage 2 ,400 sq. ft.
Managers 1 ,200 sq. ft.
Toilets 432 sq. ft.
Janitor 432 sq. ft.
total = 16,464 sq. ft.
Comfort and amenities for guest are critical, as is safety and ease of access to all services offered. Views are most important from each room, and will have natural lighting supplemented by artificial lighting. Climate conditioning and all safety code regulations will be mandatory as needed.
Double twin or 1 king size bedroom (65%,) 78,000 sq. ft.
Double king size bedroom (25%) 40,000 sq. ft.
Suites (10%) 26,000 sq. ft.
total = 144,000 sq. ft.
This shall be a controlled area from the public. Artificial lighting, and climatic conditioning will be important, with attention towards adequate hazard prevention and safeguards Laundry will be contracted out.
Linen rooms 1,600 sq. ft.
Manager 150 sq. ft.
total = 1,750 sq. ft.
This shall be a controlled security area, with direct access to outside for repair and maintenance. Artificial lighting, ventilation requirements as needed. Attention should be directed towards safety regulations and safeguards.
Boiler room Chiller/pump room Cooling tower Transformer vault
600 sq. ft. 900 sq. ft. 700 sq. ft. 200 sq. ft. total = 2,400 sq. ft.
This shall be a controlled security area, with all adequate safety needs provided for. Artificial lighting and climatic control will be used as needed.
Receiving room 800 sq. ft.
Hotel maintenance rooms furniture repair and storage carpentry plumbing painting 1,600 sq. ft.
Trash removal 300 sq. ft.
Locker rooms 1,200 sq. ft.
Manager 150 sq. ft.
total = 4,150 sq. ft.
An "open space" feeling that serves as the main focal point of the hotel should be presented. Natural light and views toward the plaza, mountain, and buildings in the immediate area are of most importance. Climatic conditioning, ease of access to the public, and artificial lighting when needed will be incorporated. All safety code regulations will
Lobby 4,000 sq. ft.
Lounge 800 sq. ft.
Toilets 400 sq. ft.
total 5,200 sq. ft.
A low key, relaxed atmosphere of quality shall be attained, and will incoporate views of the surrounding plaza and mountain areas. Natural lighting will be supplemented by artificial lighting and climatic conditioning. Safety codes of adequate nature are to be followed.
Service area 5,000 sq.
Kitchen 1,665 sq.
Manager 150 sq.
Toilets (shared with coffee shop) 400 sq.
Storage - janitor (shared with coffee shop) 200 sq.
total = 7,415 sq.
Hogg, Mary Project Architect of Adam's Rib Recreational Area HBE Corporation St. Louis, Missouri
Holder, D.C. College of Environmental Design University of Colorado at Denver 1100 14th Street Denver, Colorado 80202
Kindig, Robert College of Environmental Design University of Colorado at Denver 1100 14th Street Denver, CO 80202
Long, Gary College of Environmental Design University of Colorado at Denver 1100 14th Street Denver, Colorado 80202
Murata, Kiyoshi Murata, Outland Inc. 1433 17th Street, Suite 100 Denver, Colorado 80202
Vaughn, Susan Eagle County Planning Department Eagle, Colorado 81631
Young, Robert Adam's Rib Recreation Area, Representative Eagle, Colorado 81631