HomeMy WebLinkAboutEnvironmental Impact ReportEnvironmental Impact Report
Timber Ridge Redevelopment Project
Eagle County, Colorado
prepared for:
Vail Timber Ridge, LLC
c% Jordan Construction Services, 9639 Greenville Avenue, Dallas, TX 75243
prepared by.•
Western Ecological Resource, Inc.
711 Walnut Street, Boulder, CO 80302
January 2010
Environmental Impact Report
Timber Ridge Redevelopment Project
Eagle County, Colorado
prepared for.•
Vail Timber Ridge, LLC
c% Jordan Construction Services, 9639 Greenville Avenue, Dallas, TX 75243
prepared by.•
Western Ecological Resource, Inc.
711 Walnut Street, Boulder, CO 80302
January 2010
7
t
I
1
Table of Contents
Section / Title Page
1.0 Introduction ....................................................................................................... ............................... 1
2.0 Existing Environment ......................................................................................... ............................... 1
2.1 Hydrology ...................................................................................................... ............................... 1
2.1.1 Surface Water .......................................................................................... ............................... 1
2.1.2 Ground Water ......................................................................................... ............................... 1
2.2 Atmosphere ................................................................................................... ............................... 1
2.3 Geology & Hazards ....................................................................................... ............................... 1
2.3.1 Geology .................................................................................................. ............................... 1
2.3.2 Hazards ................................................................................................... ............................... 3
2.4 Soils ............................................................................................................... ............................... 3
2.5 Vegetation Resources ..................................................................................... ............................... 4
2.6 Wildlife Resources ......................................................................................... ............................... 4
2.7 Noise ............................................................................................................. ............................... 4
2.8 Visual Resources ............................................................................................ ............................... 4
2.9 Land Use ....................................................................................................... ............................... 4
2.10 Circulation & Transportation ........................................................................ ............................... 5
2.11 Population ................................................................................................... ............................... 5
3.0 Proposed Project ............................................................................................... ............................... 5
3.1 Apartment Buildings ...................................................................................... ............................... 5
3.2 Parking Garage .............................................................................................. ............................... 5
3.3 Clubhouse ..................................................................................................... ............................... 5
4.0 Impacts & Mitigation ......................................................................................... ............................... 5
4.1 Hydrology ...................................................................................................... ............................... 5
4. 1.1 Surface Water .......................................................................................... ............................... 5
4.1.2 Groundwater ........................................................................................... ............................... 6
4.2 Atmosphere ................................................................................................... ............................... 6
4.3 Geology & Hazards ....................................................................................... ............................... 6
4.3.1 Geology .................................................................................................. ............................... 6
4.3.2 Hazards ................................................................................................... ............................... 6
4.4 Soils ............................................................................ ............................... .............................. 8
4.5 Vegetation Resources ..................................................................................... ............................... 8
4.6 Wildlife Resources ......................................................................................... ............................... 8
4.7 Noise ............................................................................................................. ............................... 8
4.8 Visual Resources ............................................................................................ ............................... 8
4.9 Land Use ....................................................................................................... ............................... 8
4.10 Circulation & Transportation ........................................................................ ............................... 8
4.11 Population ................................................................................................... ............................... 9
5.0 Cumulative & Long -term Effects & Irreversible Environmental Changes ............. ............................... 9
5.1 Hydrology ....................................................................................................... ..............................9
5. 1.1 Surface Water .......................................................................................... ............................... 9
5.1.2 Ground Water ......................................................................................... ............................... 9
5.2 Atmosphere ................................................................................................... ............................... 9
5.3 Geology & Hazards ....................................................................................... ............................... 9
5.4 Soils ............................................................................................................... ............................... 9
5.5 Vegetation Resources ..................................................................................... ............................... 9
5.6 Wildlife Resources ......................................................................................... ............................... 9
5.7 Noise ........................................................................................................... ............................... 10
5.8 Visual Resources .......................................................................................... ............................... 10
5.9 Land Use ..................................................................................................... ............................... 10
t
1
it
r,
1
5.10 Circulation & Transportation .................... ...............................
5.11 Population ............................................... ...............................
6.0 Figures ........................................................... ...............................
7.0 Photos ........................................................... ...............................
8.0 References ..................................................... ...............................
Appendix A. Correspondence from Nancy Chick, CDPHE ................
..... ............................... 10
..... ............................... 10
..... ............................... 11
..... ............................... 24
..... ............................... 27
..... ............................... 28
List of Figures
Number / Title Page
Figure 1. Project Location Map ............................................................................. ............................... 12
Figure 2.
Aerial Photograph of Existing Development ........................................... ...............................
13
Figure3.
Regional Geology Map .......................................................................... ...............................
14
Figure4.
Project Area Geology Map ..................................................................... ...............................
15
Figure5.
Avalanche Hazard Map ......................................................................... ...............................
16
Figure 6.
Debris Flow Hazard Map ....................................................................... ...............................
17
Figure7.
Rockfall Hazard Map ............................................................................. ...............................
18
Figure 8.
Floodplains and Floodways Map ........................................................... ...............................
19
Figure9.
Soil Map ................................................................................................ ...............................
20
Figure 10.
Architectural Site Plan .......................................................................... ...............................
21
Figure11.
Front Elevation ..................................................................................... ...............................
22
Figure 12.
Conceptual Rockfall Mitigation Options .............................................. ...............................
23
List of Tables
Number / Title Page
Table 1. Ambient Air Concentration Estimates, Timber Ridge Project ..................... ............................... 2
List of Photos
Number / Title Page
Photo 1. The steep slope presents a severe rockfall hazard. ( 11/ 25/ 09) ................ ............................... 25
Photo 2. A portion of the site is mapped as a High Severity Rockfall Hazard Zone. (11/25/09).......... 25
Photo 3. Ornamental landscaping surrounds the existing Timber Ridge buildings. (11/25/09)........... 26
Photo 4. Slope between the existing buildings and Lion's Ridge Loop Road. (11/25/09) .................... 26
1
1.0 Introduction
Vail Timber Ridge, LLC has plans to redevelop the eastern 5.24 acres of the existing Timber Ridge
affordable housing development located at 1280 N. Frontage Road West in Vail, Colorado.
Specifically, the project site is located in Section 12 of Township 5 South and Range 81 West in
Eagle County (Figures 1 & 2). The project would remove nine existing apartment buildings
containing 106 units, and replace those with three new apartment buildings containing 352
housing units, a 5 -story parking garage, and a clubhouse. Thus, there would be a net increase of
246 affordable housing units, a positive impact for the Town of Vail.
This Environmental Impact Report (EIR) describes the existing environment of the project site,
presents the proposed development plan, evaluates potential impacts and mitigation, and assesses
cumulative and long -term effects and irreversible environmental changes associated with the
proposed project. Please note, Tables are included with the text, Figures are in Section 6.0, and
Photos are in Section 7.0.
' 2.0 Existing Environment
2.1 Hydrology
2.1.1 Surface Water
There are no surface water features on the Vail Timber Ridge project site. However, there is a
drainage swale located just outside the property boundary that conveys water to the southwest
between the North Frontage Road of Interstate 70 and the existing bike path (Figure 2).
2.1.2 Ground Water
Hepwork - Pawlak Geotechnical (HP Geotech) conducted a geotechnical investigation of the
project site in October, 2009 that included eight geotechnical borings with variable depths of up
to 30 feet. No free water was encountered during the study. The borings were re- examined one
or more days after the initial drilling but remained dry, however the upper soil layers were
typically moist. Although no water was encountered, HP Geotech's report states that in similar
mountainous areas with shallow bedrock, local perched water tables can develop during times of
heavy precipitation or during seasonal runoff. In addition, frozen ground during spring runoff
could potentially create a perched water table.
2.2 Atmosphere
The Colorado Department of Public Health and Environment provided data on the estimated
ambient air concentrations of six air pollutants for the Town of Vail (Chick 2009, Table 1). Local
air monitoring data do not exist for Vail, therefore Ms. Chick developed best estimates for the
general geographic area using available CDPHE data. Ms. Chick's analysis concludes that the
estimated levels of particulate matter, lead, nitrogen dioxide, carbon monoxide, sulfur dioxide,
and ozone are below state and federal standards for these pollutants. For further details, please
refer to Ms. Chick's correspondence in Appendix A. The residential land use of the project site
generates an insignificant and unmeasureable volume of particulate and gaseous pollutants.
2.3 Geology & Hazards
2.3.1 Geology
HP Geotech's 2009 Geologic Site Assessment and Preliminary Rockfall Risk and Mitigation Study
describes the regional geology and onsite features of the Timber Ridge redevelopment site, as
illustrated by Figures 3 and 4 from their report.
The near surface formation rock on the project site is the middle Pennsylvanian -age Minturn
Formation (Pm). The Minturn Formation is an interbedded arkosic grit, sandstone, conglomerate,
TABLE 1
Ambient Air Concentration Estimates
Timber Ridge Project
Vail, Colorado
Pollutant
Averaging Time
Particulate Matter Less
Annual Arithmetic
than 10 Microns (PM 10)
Mean
35 ppm
24 Hour Second
Grand Junction, 2004 -2006
Maximum
Particulate Matter Less
Annual Arithmetic
than 2.5 Microns (PM2.5)
Mean
Woodmen Exit in Colorado
98`h Percentile of 24
Hour Averages
Lead
Running 3 -month
Average
Nitrogen Dioxide (NO2) Annual Arithmetic
Mean
Carbon Monoxide (CO) 1 Hour Second
Maximum
8 Hour Second
Maximum
Sulfur Dioxide (SO2) Annual Mean
3 Hour Second
Maximum
24 Hour Second
Maximum
Ozone (03) Old Standard: 1
Hour 2nd Maximum
New Standard: 8 -hr
Fourth Maximum
Standard Estimate Data Source
50 ug/m3 15 ug/m3 Vail, 1996, 1999, 2000
150 ug/m3 35 ug/m3
15 ug/m3 9 ug/m3 Grand Junction, 2003 -2006
35 ug/m3 24 ug/m3
15 ug/m3 .0092 ug/m3 Denver Municipal Animal
Shelter, 2007 -2008
0.053 ppm
0.016 ppm
Woodmen Exit in Colorado
Springs, 2003, 2005 -2006
35 ppm
4 ppm
Grand Junction, 2004 -2006
9 ppm
2 ppm
0.030 ppm
0.002 ppm
Woodmen Exit in Colorado
Springs, 2003, 2005 -2006
0.500 ppm
0.025 ppm
0.140 ppm 0.013 ppm
0.12 ppm 0.081 ppm Rifle, 2008
0.075 ppm 0.066 ppm
* Data Provided by Nancy Chick, Environmental Protection Specialist, Air Pollution Control
Division, Colorado Department of Health and Environment. For additional detail, please refer to
her correspondence in Appendix A.
2
siltstone, shale and minor limestone and dolomite. The beds in this formation range from
' cemented and hard to non - cemented but firm. The bedding strikes to the northeast and dips
about 30 to 40 degrees to the northwest. On the hillside to the northwest of the project site the
rock is usually covered by thin colluvium but a prominent outcrop band is present near the ridge
' crest that forms the top of the hill, as illustrated by Figure 4. This outcrop band has produced
rockfall in the past and rockfall blocks are common on the hillside below the outcrop.
The Gore Creek Valley in the project area was the site of valley glaciers during the Pleistocene.
Remnants of a middle Pleistocene -age, Bull Lake lateral moraine (Qm2) are present on the lower
valley side just to the southwest of the project site. The project site is underlain by a late
Pleistocene -age, Pinedale terminal and ground moraine (Qm1). The Pinedale till encountered in
' geotechnical borings was a dense to very dense deposit of gravel- to large boulder -sized rock in a
silty sand matrix.
1
1
Thin colluvium covers the Minturn Formation on the hillside to the northwest of the project site.
Soil exposures in the Lion's Ridge Loop road cut indicated that the colluvium is a matrix
supported deposit of angular rock blocks from gravel- to large boulder -size in a mixed silt, sand,
and clay matrix. The rocks in the colluvium are exclusively from the Minturn Formation.
HP Geotech also completed a Geotechnical Engineering Study for the Timber Ridge project site in
October, 2009. Eight exploratory borings were conducted to evaluate subsurface conditions. The
borings revealed a variable depth of fill materials underlain by subsoils characterized by dense,
silty gravel, cobbles, and boulders. In Borings 5 and 7, about 1 1/z - 3 feet of mainly sandy silt and
clay was encountered between the fill and the coarse granular soils. Below depths of 7 -29 feet in
Borings 1, 3, and 5, hard to very hard siltstone /sandstone bedrock was encountered. Fill material
was characterized by a mixture of sandy clay and gravel. HP Geotech's report concludes that the
relatively dense, coarse granular soils and bedrock are suitable to support the apartment buildings
and parking structure.
2.3.2 Hazards
Avalanche. The project site is outside the hazard zones for avalanche, as illustrated by Figure 5,
which was adapted from the Official Avalanche Hazard Map for the Town of Vail.
Debris Flow. The project site is outside the hazard areas identified for debris flow on the Official
Debris Flow Hazard Map for the Town of Vail (Figure 6).
Rockfall. The northwest edge of the Timber Ridge project site is within an area identified as a
High Severity Rockfall Hazard Zone on the Town of Vail's Official Rockfall Hazard Map (Figure 7;
Photos 1 & 2). In addition, HP Geotech completed a Geologic Site Assessment and Preliminary
Rockfall Risk and Mitigation Study (2009) that identified specific rockfall risks. Their report states
that "exceptional, very large rockfall blocks are present on the hillside to the west of the proposed
redevelopment area." Their field measurements indicate the blocks have a maximum dimension
between 4.8 and 7.7 feet, and an estimated weight between 2.8 and 17.3 tons. Although they
conclude that future rockfalls would likely be infrequent, if a rockfall were to hit the building
facilities it has the potential for severe building damage and could harm building occupants.
Floodplains and Floodways. The Timber Ridge project site is outside the FEMA mapped 100 -year
floodplain and the floodway for Gore Creek, as illustrated by Figure 8.
2.4 Soils
The Natural Resources Conservation Service (NRCS) has mapped soils on the Vail Timber Ridge
project site as part of a regional mapping effort (NRCS, 2008). As illustrated by Figure 9, the
project site contains two soil map units: #46, Forsey Cobbly Loam, 12 to 25 % slopes, and #104,
Torriorthents - Camborthids -Rock outcrop complex, 6 to 65% slopes.
3
1
Forsey Cobbly Loam is a deep, well- drained soil found on alluvial fans, mountainsides, and ridges.
About 25 -30% of the surface is covered with cobbles. This map unit is characterized by a surface
layer of dark grayish brown cobbly loam about ten inches thick. The underlying subsoil is very
cobbly clay loam about 12 inches thick. About 5% of the acreage is covered by small sandstone
outcrops.
The Torriorthents - Camborthids -Rock outcrop complex is on moderately sloping to steep, mainly
south - facing mountainsides, hills, ridges, and foot slopes, including canyonsides above major
drainageways. The unit is composed of about 45% Torriorthents, 20% Camborthids, and 15%
Rock outcrop. The Torriorthents are shallow or moderately deep and are well drained. The
surface layer is generally covered with stones, and ranges from reddish brown to brown. The soils
range from sandy loam to clay loam and have a variable content of gravel, cobbles, and stones.
The depth to shale or sandstone is four to 30 inches. The Camborthids are shallow to deep and
are well drained. These soils typically have a light colored surface layer and are clay loam or
loam. The soils are generally free of stones throughout the profile but scattered basalt stones,
cobbles, and sandstone rock fragments are on the surface. The Rock outcrop consists primarily of
' barren sandstone, shale, and basalt.
2.5 Vegetation Resources
The Timber Ridge project site is an existing development with no native plant communities
(Figure 2). Ornamental landscaping surrounding the existing buildings generally consists of
bluegrass and fescue lawns with tree and shrub plantings including blue spruce (Picea pungens),
' aspen (Populus tremuloides), poplar (Populus sp.), silver sagebrush (Artemsia cana), serviceberry
(Amelanchier alnifolia), spirea (Spiraea sp.), and privet (Ligustrum vulgare) (Photo 3). A steep
slope between the condominium buildings and Lions Ridge Loop Road is dominated by the
introduced grasses smooth brome (Bromus inermis) and intermediate wheatgrass (Thinopyrum
intermedium) growing with numerous weedy forbs including the noxious weed plumeless thistle
(Carduus acanthoides), prickly lettuce (Lactuca serriola), tumble mustard (Sysimbrium altissimum),
and salsify (Tragopogon dubius) (Photo 4). A small stand of serviceberry shrubs is also present on
' the hillside.
2.6 Wildlife Resources
' The existing Timber Ridge project site provides limited wildlife habitat due to the lack of native
vegetation, the density of existing buildings, and proximity of the Interstate -70 corridor. Urban
adapted species present include songbirds and small mammals.
' 2.7 Noise
The existing Timber Ridge development generates some noise from the current residents and their
vehicles, however any noise generated onsite is negligible given the proximity of the Interstate -70
corridor and the noise generated by vehicular traffic on the highway and frontage road.
2.8 Visual Resources
The existing Timber Ridge development was constructed in 1981. The appearance and condition
of the nine buildings has deteriorated and now requires many costly repairs. The condition of the
' existing Timber Ridge apartments and the high cost of required maintenance and repairs were
important factors in the decision to redevelop the site.
' 2.9 Land Use
The Town of Vail's official zoning for the Timber Ridge Project site is Housing (H). The Current
Land Use Map indicates a High Density Residential Development. The proposed redevelopment
' area contains nine apartment buildings with 106 residential units.
4
' 2.10 Circulation & Transportation
The Timber Ridge project site is located along the Interstate -70 North Frontage Road between the
' Lionshead and West Vail Exits. Specifically, it can be accessed by traveling approximately 1.17
miles east of the West Vail exit or 1.42 miles west of the Lionshead exit along the North Frontage
Road. Two driveways from the frontage road provide access into the development (Figure 2).
A Traffic Impact Study completed by Kimley -Horn and Associates, Inc (2010) evaluated vehicle
trips generated by the existing Timber Ridge development, as well as person trips using the Town
of Vail's public transportation system. The traffic study was conducted on December 30, 2009, a
peak day during the peak of the winter ski season. Of the 198 units in Timber Ridge, 171 were
occupied at the time of the study. These units generated 25 morning peak hour and 46 afternoon
peak hour vehicle trips. For residents using the public transportation system, the development
generated 106 morning peak hour and 137 afternoon peak hour person trips. Thus, the majority
of the residents in Timber Ridge use the public transportation system for their mode of travel.
2.11 Population
The proposed Timber Ridge redevelopment project encompasses the eastern portion of the
existing residential development (Figure 2). Within the redevelopment area, there are nine
' buildings that contain a total of 106 units, with an estimated total population of 424 residents.
' 3.0 Proposed Project
3.1 Apartment Buildings
The proposed Timber Ridge project will consist of three 5 -story apartment buildings that adjoin a
5 -story parking garage. These are referred to as the East, West, and Center apartment buildings.
The three buildings will have a combined total of 352 units. The East and West buildings would
' be on the sides of the parking garage, while the Center building would be constructed across the
front of the garage such that it would obscure the garage from the Frontage Road. The proposed
development plan is illustrated by Figure 10. Figure 11 presents a front elevation view.
' 3.2 Parking Garage
A five -story parking garage will adjoin the three apartment buildings. The garage would be
accessed from an entryway on the North Frontage Road, and would contain 522 parking spaces.
Please note, 18 additional surface parking spaces would be located within the redevelopment
area, for a grand total of 540 spaces. Twelve of these spaces would provide handicap parking.
3.3 Clubhouse
A 4,689 square foot clubhouse would be constructed within the first and second floors of the
West Building. The clubhouse would include exercise areas, offices, a cyber caf6, a club room,
and a business /conference space.
' 4.0 Impacts & Mitigation
4.1 Hydrology
4. 1.1 Surface Water
There are no surface water features within the proposed redevelopment area of Timber Ridge.
Storm water runoff will be managed in accordance with state law. Best management practices
S
J JJ
I
1
including sediment traps and silt fencing will be used during construction to limit potential surface
water impacts.
The proposed redevelopment area will have onsite storm water detention. Storm water runoff
from drain inlets will be conveyed via buried culverts to a belowground detention area
constructed of a 72 -inch pipe. Three vortex sand and oil separators will be used to filter runoff
before it enters the buried detention pipe. In addition, the detention pipe acts as a water quality
feature because fines that pass through the sand and oil separators will settle out within the pipe.
The release structure of the buried detention pipe will convey water to a buried 24 -inch culvert
which will tie -in to an existing culvert that conveys runoff south under the Interstate 70 Frontage
Road to the CDOT Right -of -Way. Thus, storm water runoff will be released in the location of the
historic discharge.
4.1.2 Groundwater
HP Geotech's 2009 report provides recommendations for mitigating the potential effects of
groundwater on the proposed development. Specifically, it recommends that below -grade
construction such as retaining walls, crawlspace, and basement areas be protected from wetting
and hydrostatic pressure buildup by an underdrain system. In addition, it recommends placing a
minimum 4 -inch layer of free - draining gravel beneath basement slabs to facilitate drainage. The
under slab gravel should be connected with the perimeter underdrain system by interior lateral
subdrains.
4.2 Atmosphere
The proposed redevelopment of Timber Ridge will have a small and unmeasureable impact on air
quality. There will be a short -term increase in hydrocarbon pollutants and dust generated during
the construction process. There would also be small releases of hydrocarbon pollutants generated
by activities such as heating the new development.
The traffic study prepared by Kimley Horne (2009) estimated traffic volumes for the development
in 2015 following redevelopment of the eastern portion of Timber Ridge. During the peak winter
ski season, their analysis indicates the completed project is expected to generate 42 and 78 new
vehicle trips during weekday morning and afternoon peak hours, respectively. These additional
vehicle trips would slightly increase the levels of hydrocarbon pollutants over the existing
condition. Overall, however the project is expected to reduce traffic within the Town of Vail by
providing employee housing in close proximity to work. Employees that now commute from
greater distances outside of Vail would have a reduced commute distance or would be more likely
to use public transportation, which would have a positive impact on air quality. The magnitude of
this impact on air quality has not been estimated, but it would likely be small and unmeasureable.
4.3 Geology & Hazards
4.3.1 Geology
HP Geotech's Geotechnical Engineering Study (2009) provides specific recommendations based
on their subsurface investigations of the Timber Ridge project site. It states that the native soil and
bedrock are suitable for supporting the apartment buildings and parking garage, but that all fill
material and debris from the existing development should be completely removed from below the
proposed building areas.
4.3.2 Hazards
Avalanche, Debris Flow, and Floodplains & Floodways. The project site is outside the hazard
zones for avalanche and debris flow, as illustrated by Figures 5 and 6, therefore no mitigation is
required for these hazards. Likewise, it is outside the FEMA mapped floodplain and floodway for
Gore Creek (Figure 8).
R
Rockfall Hazard. A portion of the Timber Ridge project site is within an area identified as a High
Severity Rockfall Hazard Zone on the Town of Vail's Official Rockfall Hazard Map (Figure 7).
Hepworth - Pawlak Geotechnical's Draft Geologic Site Assessment and Preliminary Rockfall Risk
and Mitigation Study (HP Geotech, 2009) presents four conceptual options for mitigating rockfall
hazards on the project site. The four mitigation options vary in the placement and type of barrier
used, as illustrated by Figure 12.
IThe first mitigation option is the placement of either a wire rope net barrier or MSE barrier located
on the property just south of Lion's Ridge Loop Road. The second option is a wire rope net
barrier located off of the project site near the top of the Lion's Ridge Loop road cut. The third
option is to install a wire rope barrier off of the property near the base of the outcrop start zone.
Finally, option four is to stabilize the rock outcrop with and anchored steel mesh net.
The Colorado Rockfall Simulation Program (CRSP 4.0) was used to evaluate the four different
barrier options by simulating rockfall events. The program predicts the velocity, bounce height,
and kinetic energy of rocks taking into account the slope profile, rebound and frictional
' characteristics of the slope, and rotational energy of the rocks. Using this program, HP Geotech
developed conceptual design information for each of the barrier options including the height,
width, length, and impact energy they should withstand, to be used for feasibility evaluations and
preliminary cost estimates. The conceptual design characteristics were developed for barriers that
provide two levels of protection: 90% probability (10% chance it would be exceeded) and 98%
probability (2% chance it would be exceeded) assuming a spherical rock with a diameter of 6.6
feet and a weight of 12.4 tons. The level of protection to be used will depend on the degree of
' risk acceptable to the owner and governmental regulatory agencies. HP Geotech states that
additional studies would be needed for specific design evaluations. In addition, the report briefly
summarizes the equipment and access needed for installation of barriers under the four options.
' For Option 1, there are two alternatives: placement of a 900 - foot -long MSE barrier or wire rope
barrier entirely on the Timber Ridge property. Both barrier options would require a nearly level,
retained fill bench wide enough to construct the barrier. Construction access could be from the
property or from Lion's Ridge Loop Road. For both alternatives, rockfall kinetic energy and barrier
heights at the 90 and 98 percent probability levels are within the capacity of commercially
available MSE and wire rope net barriers.
Option 2, the 990 - foot -long wire rope net barrier would require an easement on the hillside north
of Lion's Ridge Loop Road. Little permanent hillside disturbance would be required, and most
construction access could likely be accomplished using a crane located on Lion's Ridge Loop
Road. For this option, the rockfall kinetic energy and barrier heights at the 90 and 98 percent
probability levels are within the capacity of commercially available wire rope net barriers.
' Option 3, a 1,060- foot -long wire rope net barrier would also require an easement above Lion's
Ridge Loop Road. Although there would be little permanent disturbance to the hillside,
construction access would be difficult and would require an access trail, highline, helicopter, or a
combination of these. For this option, the rockfall kinetic energy and barrier heights at the 90 and
98 percent probability levels are within the capacity of commercially available wire rope net
barriers.
Option 4, stabilization of the rock outcrop using an anchored steel mesh net, would require an
easement on the hillside above Lion's Ridge Loop Road. Grouted rock bolts would be used to pin
the flexible steel mesh netting to the outcrops. There would be little permanent hillside
disturbance with this option. Construction access would be difficult, and would require an access
trail, highline, helicopter, or a combination of these. It should be possible to provide effective
outcrop stabilization with commercially available anchored, flexible steel mesh netting systems.
7
1
I]-
4.4 Soils
The native soils of the site were disturbed when the existing Timber Ridge development was
constructed. Fill material of variable depths was used to create a level development area and
topsoil was applied to the fill to create habitats for ornamental vegetation. The existing fill
material and topsoil would be removed and additional topsoil would be brought to the site for the
proposed landscaping.
4.5 Vegetation Resources
The project site does not support any native plant communities, but contains ornamental
landscaping surrounding the existing buildings. These landscaped areas will be impacted when
the site is redeveloped and will be replaced with similar areas of ornamental landscaping in
proposed courtyards and in areas surrounding the new buildings (Figure 10).
4.6 Wildlife Resources
The existing Timber Ridge project site provides only limited wildlife habitat for urban adapted
species. During the construction process, these urban - adapted species may be temporarily
displaced. When the redevelopment is complete, the urban - adapted wildlife would return to the
project site.
4.7 Noise
The proposed project would create a short -term increase in noise levels due to heavy equipment
use during the construction process. By 2015, redevelopment of the eastern portion of Timber
Ridge is expected to generate approximately 42 peak morning and 78 peak afternoon new vehicle
trips per day, which would create a slight, but permanent increase in the ambient noise
environment of the area. However, given the background noise generated by the proximity of the
Interstate -70 corridor, the added impact would be negligible.
4.8 Visual Resources
The existing Timber Ridge project was constructed in 1981. The buildings have aged and they
now require significant repairs and maintenance. Replacing these deteriorating buildings with
attractive, modern apartment buildings would improve the visual character of the area.
The existing three -story buildings would be replaced with taller five -story buildings. However the
parking garage would be constructed behind the Center apartment building, thus producing an
attractive fagade that will be visible from the Interstate -70 corridor (Figure 11). Due to the steep,
undeveloped slope above Lion's Ridge Loop Road, the taller buildings would not obscure views
from the hillside behind the development.
1 4.9 Land Use
The proposed land use is consistent with the Town of Vail's zoning for the project site (H-
Housing) and would replace one high - density residential development with another similar
project.
4.10 Circulation & Transportation
I The traffic study prepared by Kimley Horne (2009) estimated traffic volumes for the development
in 2015 following redevelopment of the eastern portion of Timber Ridge. During the peak winter
ski season, their analysis indicates the completed project is expected to generate 42 and 78 new
vehicle trips during weekday morning and afternoon peak hours, respectively. In addition, it
would generate 184 new peak morning and 232 new peak afternoon person trips on the public
transit system. Overall, however the project is expected to reduce traffic within the Town of Vail
by providing employee housing in close proximity to work. Employees that now commute from
u
greater distances outside of Vail would have a reduced commute distance or would be more likely
to use public transportation.
4.11 Population
' The proposed apartment buildings will provide year -round affordable housing to 552 -570
individuals, compared with approximately 424 individuals in the existing buildings. Thus, there
would be an increase of approximately 128 -146 people residing in the project area when the re-
development is complete.
! 5.0 Cumulative & Long -term Effects & Irreversible Environmental Changes
5.1 Hydrology
5.1.1 Surface Water
The proposed redevelopment of the eastern portion of Timber Ridge would have no cumulative,
long -term effect or irreversible environmental change on the surface water hydrology of the
project site.
5.1.2 Ground Water
The proposed development would have a slight, cumulative long -term effect or irreversible
environmental change on the ground water hydrology of the project site due to dewatering of
building foundations via underdrains.
! 5.2 Atmosphere
The slight increase in hydrocarbon pollutants generated by the development and associated
vehicular traffic represents a cumulative and long term effect. However, Kimley- Horn's traffic
' analysis concludes that redevelopment of Timber Ridge would have an overall effect of reducing
traffic within Vail because employees would reside closer to their workplace. The majority of
residents in Timber Ridge utilize public transportation.
5.3 Geology & Hazards
The long -term risks presented by the rockfall hazard could be mitigated by any of the four
conceptual options presented in HP Geotech's 2009 Geologic Site Assessment and Preliminary
Rockfall Risk and Mitigation Study. After the feasibility analysis and preliminary cost estimates are
completed, an option can be selected and further studies would be needed to develop more
precise design specifications.
5.4 Soils
Because this is a redevelopment project, it would not result in any new cumulative or long -term
impacts to the native soil. As described in the Geotechnical Study completed by HP Geotech, the
site is overlain by fill material from the initial development.
5.5 Vegetation Resources
The proposed project would create only a negligible long -term change in the plant community as
areas of ornamental vegetation are impacted and replaced with similar ornamental vegetation.
5.6 Wildlife Resources
1 The proposed redevelopment would not have any significant long -term impacts or irreversible
environmental changes on wildlife resources. The site is already a high- density residential
development, and there will be no change in land use or vegetation resources.
! a
1
5.7 Noise
Ll
J
Li
Noise generated by the proposed development and associated vehicular traffic would create a
slight cumulative and long -term environmental change, however given the proximity of the
Interstate -70 corridor, this change will be negligible.
5.8 Visual Resources
Redevelopment of the eastern portion of Timber Ridge would create an irreversible change on the
visual resources of the area. However, this would be a positive impact because the aging
buildings would be replaced with newer, updated buildings with an aesthetically pleasing
architectural style that compliments other developments within the Town of Vail (Figure 11).
5.9 Land Use
The proposed project would not result in changes to the land use as one high- density residential
development will be replaced with a similar high- density residential development.
5.10 Circulation & Transportation
Long -term traffic estimates included in Kimley- Horn's Traffic Impact Study (2010) assume the
entire Timber Ridge site is re- developed to include 700 units by 2025. Their analysis estimates
the development would generate 77 new vehicle trips during the peak morning hour and 142
new vehicle trips during the peak afternoon hour of the peak winter ski season. Likewise there
would be 337 new person trips during the peak morning hour and 424 new person trips during
the peak afternoon hour on the public transportation system. Kimley -Horn reports that the full
build -out may have a significant impact on the Town of Vail's public transit system and states that
additional busses may be needed to accommodate this use.
5.11 Population
The redeveloped apartment buildings will support a larger population, an increase estimated
between 128 -146 people. This represents a cumulative and long -term increase in the population
of the Town.
10
t
u
11
6.0 Figures
-R 81 W I R 80 W
378000m E. 379000m E. 380000m E. WGS84 Zone 13S
BASE: USGS 7.5 Minute Vail West, Colorado Quadrangle FIGURE 1. Project Location M
Photorevised: 1987 ro1 ec ocaon a P
Timber Ridge Project
WESTERN
ECOLOGICAL
pp RESOURCE, INC. Scale 1" = 2000'
Map wy��� sa.<� . ear. � �� 711 Location
COLO DO Contour Interval = 40'
' 12
f
a�y
,• � : , � r- , s � Figure 2. Aerial Photograph
Timber Ridge
... • o ey
r]`c
b
Existing Timber
Ridge Buildings
�S t
h
a!
A Y�
! Timber Ridge Boundary Area to be Redeveloped
v
Ile
'��f �, :t x I ,�'�`�� ,.� r'•"a ^V I � c ' r > a t � r +. .! r
Wr
{{ Y
�� � �..��',.;.ar• yf,�vF- . f -:.,. ,� . i ysl' /1 ' '�f°''' � P�1. � I
t
r.,'S/ e�'P- ' � r,.,�„�� i jl..` ,,, � Y J �,,, ' � �r„r- y � • '}'�,y:,:�. - *y- r'U�
`{
I `�T
I� ♦g'4
R p41
a
�YfVe r
Date: January 2010
Scale: 1 in = 150 ft
prepared by:
Western Ecological Resource, Inc.
711 Walnut Street
Boulder, CO 80302
13 (303) 449 -9009 FAX (303) 449 -9038
TKs T Hot
Mz � T T I TKs Granby -p Mz
Mz Kremmling X Y r Mz \ YXr
g YXr TKi
YX r
YXr N� C n� r a
Ti (D � (`j(( wiFork
Mz t s YX S
Res. Ts TKs Xr Tabemash
YXr IS ,p
� o� � Ts
Pz � YXr z Eraser T
G v
Ts Tv Tv N d� z
Ti
TV Mz �2a Tv
YXr
i v Gree
tn
Sta Bridge Mz Res. S
TV Tv
Ts
r Mz
TV ��fd?r Ts
BUrnS
C L \ psi Ti b TK
Mz % � . qd TKi,]
olcott C
o �rD
dG
Sy PZ Georyeto
�1 Sowards � Project YXr �1P
Tv Avon Site Silvertnomm T
® Vail ® \ V
Pze
1O Ts s YXr
1z Ts Pz ` °'� Mz Ti
Pz tdintum
Pz C� Ti
TKi Frisco
Red Cliff �7 \
Mz P YXr / 3
YXr
Copppe ® TKi
/K ` e ke '
i z Pando TK\, 1
QJ 0 Ki
Pz rK TKi TKi
TKi q)
Pz Ti IFO�
T , Pz , �R
Pz j �O TKi TV
YXr TKi
4m Jefferson Mz
Ti Climax ) Pz
P ° p / TKi
z TKi
RTKi pJ A ' TKi
y (j comp
TKs
` Zi
w rK�
.S� TKi Tur oise Pz TKi ® O Mz F r0
r
rj1 Res � KI Alma
Explanation:
Ts Post - Laramide Sediments Mz Pre - Laramide Mesozoic Sediments Contact
EDPost - Laramide Volcanics Paleozoic Sediments High -Angle Faults
Ti Post - Laramide Intrusives - Pennsylvanian Evaporites Thrust Faults 0 7 mi.
TKs Laramide Basin Sediments YXr Precambrian Crystalline Rocks Synclines I I I
Scale 1 in. = 7 mi.
Laramide Intrusivesp� Highways Modified from: Tweto (1979)
G49 ;tech Vail Timber Ridge Redevelopment Project Figure 3
109 3108 Re ional Geolo Ma g
HEPWOR- rN- PAWLAK GEOTECHNICAL
FIGURE 3. Regional Geology Map
Timber Ridge Project
14
3
5e` iV
1- 'X
E
0
E
0
109 310B GoMech
HEFWORTI+PAWLAK GEOTECHNICAL
E CO3
S E
0
a U) 0_J
O 2 4)
C
n
C: Ca 'D
.0 00 (D
O
2
m
to
C:
0 0 (D :E:
CO
W1
o
ti
E
:3
CL
M
E
C
0
CL 0
'CO,
C
7i :5
0
% 3 2
n 0 0 0 a > 4)
a-
C3
o
di
G
E2
C
C14 >
C
C3 < E
E 4i
Li
LL
0 0)
'D Ca
U Ca 0 6
M 0
if
Q)
M 0 01 O.S
CL
22 E Om
Wa
Vail Timber Ridge Redevelopment Project Figure 4
Project Area Geology Map
15
FIGURE 4. Project Area Geology Map
Timber Ridge Project
Official Avalanche Hazard Map
Town of Vail, Colorado
Project Site
Thin Is to certify that this is the Offlclsl Avalanche
Hazard Map of the Toren of Veil, Colorado as
adopted Council on October 77, 2000
Mayor, T
t
6 $ A L
a
in accordance with Resdudon No. 73, Series
TOWN "�°°°
I
I
Attest: Town Cleric. Town of Vail
4 . A'r..,
Prodreed by the Depertrnem of Commurtty Development _
Source: Town of Vail Website: www.vailgov.com
Adapted from official Town of Vail Map
Hazard Zones
High Hazard - Red Zone
Moderate Hazard - Blue Zone
Possible Avalanche Influence Zone
Powder Blast
FIGURE 5. Avalanche Hazard Map
Timber Ridge Project
N
16 oWESTERN
ECOLOGICAL
torRESOURCE, INC.
711 Walnut 3rree[ •Boulder, CO aD302
t
t
1
1
1
1
1
1
1
1
Is
Official Debris Flow Hazard Map
Town of Vail, Colorado
N I
V
This is to certify that this is the Official Debris Flow
Hazard Map of the Town of Vail, Colorado as
adopted by Council on October 17, 2000
in accordance with Resolution No. 13, Series
of 2000.
Project Site
Mayor, Towrlbf Vail `
SAttest: Town Clerk, Town of Vail �taas
r+b.1.r a
Source: Town of Vail Website: www.vailgov.com FIGURE 6. Debris Flow Hazard Map
Adapted from official Town of Vail Map Timber Ridge Project
N
Hazard Zones
- High Hazard Debris Flow WESTERN
Moderate Hazard Debris Flow ECOLOGICAL
High Hazard Debris Avalanche oot RESOURCE, INC.
17 711 Walnut Street • Bo IO r. CO 90302
Official Rockfall Hazard Map
Town of Vail, Colorado
y
f.
This is to certify that this is the Official Rockfall
Hazard Map of the Town of Vail, Colorado as
adopted by Council on October 17, 2000
in accordance with Resolution No. 13, Series
of 2000.
Project Site
.� -
« 44,
kleWr, TovoW Vail
Jrub-- ZL�� a =
Attes t: Town Clerk, Town of Vail
Source: Town of Vail Website: www.vailgov.com FIGURE 7. Rockfall Hazard Map
Adapted from official Town of Vail Map Timber Ridge Project
N
Hazard Zones
Rockfall Hazard with Approved Mitigation
High Severity Rockfall WESTERN
Medium Severity Rockfall D ECOLOGICAL
a RESOURCE, INC.
44
18 711 W 1— Street . Bwlder, CO 80002
project Site
/ z
U
Q
1' G�
- onovan
Park °��"'
M 461
Z 4. J
152 -1554 • Ix �•
,_-
s
250 0 250 500 Feet
M d �`r� This map is for flood insurance purposes only; it does not necessanly
show all areas subject to flooding in the community or all planimebic
wfeatures outside of the indicated flood hazard areas. 100 0 100 200 Meters
Z This map was created by the Town of Vail GIS Department. Use Emil
33 ■ w � QQ of this map should be for general purposes only. The Town of Vail - --
� 0 �� � does not warrant the accuracy of the information contained herein.
,0
1�
01
Source: Town of Vail Website: www.vailgov.com FIGURE 8. Floodplain & Floodway Map
Adapted from official Town of Vail Map Timber Ridge Project
Legend:
N
FEMA Flood Hazard
•
Gore Creek
•
Building Footprints
Flood Hazard Extent
U Floodway
0
Parcels (approximate)
WESTERN
ECOLOGICAL
1 %Annual Chance of Flood Hazard
Q
Vail Town Boundary
ry
Or RESOURCE, INC.
19
711 walnut Street . Boulder, CO $0302
vp
Awl
i r •OF
$` * •
F
A
i
VOW
�# �t• k ,
' �• r` #�'• .
q �� %—ee
rr y, I
ti
4
I `
w.
\` opop, ,"s
r.
• ;t
20
0.4
V
rL
� L
�a
'0 a�
cn :a
W
L
cm E
iz r
o
P
0
�mw
o�
w _ P
4 a0
r � e
Y
Y � O
Y
O LL
a
O O
CD N
co
0
o LO
C) O
N (p
X
O
O d
O E
U') O
O CJ
Q
O
Z3
n0
O Y
0
0
L
N p
� L
(6 E
O co
-U
-0 0
O
>1 o
Y)
` L L
0
LL
� (0 O
co
0
� c D
0
m a
U Co
C a cn
J
EXISTING
BLDG.J
LION'S RIDGE LOOp
EXIT
y� a i
," � . 11111111111111111111
I . •- . OR
. 1111111113,1!11111111 „�
" i -
�
mesas:!! a�
OWN-
UNIT TABULATION 1
12/29/09
UNIT NAME
UNIT TYPE
NET AR SF
5-STORY
TOTAL NET
Al
STUDIO
391
22
6.25%
8,602
1- BEDROOM
A2
lbr /lba
527
100
28.41%
52,700
45.5%
A3
lbr /lba
647
38
10.80%
24,586
81 -1ST
2br /2ba
I
17
LLLLISTING
13,294
2- BEDROOM
' FICE
2br /2ba
812
.
5-STORY
20.45%
58,464
54.5%
B2
2br/2ba
46
13.07%
41,078
62 -TOP
-lac"
990
4
1,14%
3,960
f ... ..4.� a
2br /2ba
926
10
2.84%
9,260
...A
B3
2br/2ba
969
43
1222%
41,667
OW
n
TOTALS
ni
352
100.0%
253,611
UNIT AVERAGE NET SF: 720
NORTH FRONTAGE WEST
INTERSTATE HIGH
0.70
UNIT TABULATION 1
12/29/09
UNIT NAME
UNIT TYPE
NET AR SF
UNIT COUNT
%
TOTAL NET
Al
STUDIO
391
22
6.25%
8,602
1- BEDROOM
A2
lbr /lba
527
100
28.41%
52,700
45.5%
A3
lbr /lba
647
38
10.80%
24,586
81 -1ST
2br /2ba
782
17
4.83%
13,294
2- BEDROOM
B1
2br /2ba
812
72
20.45%
58,464
54.5%
B2
2br/2ba
893
46
13.07%
41,078
62 -TOP
2br/2ba
990
4
1,14%
3,960
B3 -1ST
2br /2ba
926
10
2.84%
9,260
B3
2br/2ba
969
43
1222%
41,667
TOTALS
352
100.0%
253,611
UNIT AVERAGE NET SF: 720
D
SITE PLAN
SITE DEVELOPMENT STANDARD CALCULATIONS
LOT AREA: 5.24 ACRES
CURRENT ZONING: H (HOUSING)
TOTAL UNITS: 352
DENSITY: 67 UNITS PER ACRE
BUILDING HEIGHT: 5 -STORY
CLUBHOUSE: 4689 SF.
BUILDING GROSS AREA: 305,400 SF.
GARAGE GROSS AREA 164,250 SF.
PAVED AREA: 3,000 SF.
PARKING & DRIVEWAYS: 31,308 SF.
BUILDING COVERAGE: 94,100 SF. C41 %)
SNOW STORAGE AREA: 10,000 SF. (30% PAVED AREA)
LANDSCAPE AREA: 72.372 SF.1.66 ACRES (31% SITE AREA)
PARKING REQUIRED: 1.5 SPACES FOR UNITS LESS THAN 500 SF.
2 SPACES FOR UNITS MORE THAN 500 SF.
TOTAL 693 SPACES REQUIRED WITHOUT REDUCTION
TOTAL 520 SPACES REQUIRED WITH 25% REDUCTION
( 25% COMPACT CAR SPACES ALLOWED)
PARKING PROVIDED:
GARAGE: 522 SPACES
SURFACE: 18 SPACES
TOTAL: 540 SPACES
INCLUDING 106 COMPACT SPACES (19%),12 HANDICAP SPACES
( 1.53 SPACES PER UNIT)
TYP. PARKING STALL: 9'X 19' (SURFACE); 9'x 24' ( PARALLEL)
9 X 18' ,::(GARAGE)
81X 16' ( COMPACT)
FIGURE 10. Architectural Site Plan
Timber Ridge Project
21
41
fl-
to
�o
°�o
_o
u 2 N
_ S E
°—'o (D
c�
o U)U
o � �
�f �• 11.1. �.
.w- Wow
`
LL
•f IIf1 fff 1� 111 � � �� \ •'���� .,
'� ►111 f f111fQi `� \ '�
��111111111111�1 \ ���
`11 11 •, t G�i
• �j 1111U ��\ �� ca IL
•, � 14 —WANW VNEM
11 1 •
F+11� f111f�,�� \ „ '1
.. ��1111f1��
�• 111111111.E , \`�
• � 11 I f1►
14 0
•• • ,11 1111• `
AF 0
W CL
.►..�r��
4,,4-�111�1� 1'►
WN— • +�If11f1
.�. . 11 11 1�♦
` QV ,
R W4
ca
0 CL CL
1V N
r • ;, '��f�1111•� • ••�
�•�, , ��� 111 �1� �,
111' ;; ice` �•
�` 111,,x•... +,'
'..
W. • • • •
Na CL
Ul
Vail Timber Ridge Redevelopment • -
M — u — •
FIGURE 12. Conceptual Rockfall Mitigation Options
Timber Ridge Project
23
fl
24
7.0 Photos
I
Photo 1. The steep slope behind the proposed Timber Ridge redevelopment site presents a
severe rockfall hazard. 01/25/09).
Photo 2. The northwest edge of the Timber Ridge project site is mapped as a High Severity
Rockfall Hazard Zone by the Town of Vail. (11/25/09).
25
u
LI
Photo 3. Ornamental landscaping surrounds the existing Timber Ridge apartment buildings.
(11/25/09).
Photo 4. The slope between the existing buildings and Lion's Ridge Loop Road is
dominated by introduced grasses and weedy forbs. (11/25/09).
f3:
8.0 References
' Chick, Nancy. 2009. December 1, 2009 correspondence to Heather Houston of Western
Ecological Resource.
HP Geotech. 2009. Geologic Site Assessment and Preliminary Rockfall Risk and Mitigation
Study, Vail Timber Ridge Redevelopment Project, 1280 North Frontage Road West, Vail
Colorado. Prepared for: Vail Timber Ridge, LLC. Prepared by: Hepworth - Pawlak
Geotechnical, October 27, 2009.
HP Geotech. 2009. Geotechnical Engineering Study, Proposed Timber Ridge Redevelopment,
' 1280 North Frontage Road West, Vail, Colorado. Prepared for: Vail Timber Ridge, LLC,
October 27, 2009.
' Kimley -Horn and Associates, Inc. 2010. Traffic Impact Study, Timber Ridge. Prepared for: Town
of Vail. Prepared by: Kimley -Horn and Associates, Dever Colorado, January 2010.
I I
� I
IL
� I
� I
it]
� I
� I
� I
I I
27
L
Appendix A. Correspondence from Nancy Chick, CDPHE
28
STATE OF COLORADO
Bill Ritter, Jr., Governor
Ned Calonge, M.D., Interim Executive Director
�Q
Dedicated to protecting and improving the health and environment of the people of Colorado
4300 Cherry Creek Dr. S. Laboratory Services Division
�e-
Denver, Colorado 80246-1530 8100 Lowry Blvd.
W;��
Phone (303) 692.2000 Denver, Colorado 80230.6928
on other data our agency has. The estimates and the basis for each are given in the Table below.
TDD Line (303) 691 -7700 (303) 692 -3090
Colorado
Located in Glendale, Colorado
s Health
of Public Health
http: / /www.cdphs.state.co.us
and Environment
Heather Houston
Western Ecological Resource
Via Email: heather @westcmeco.com
December 1, 2009
Dear Ms. Houston,
You requested background pollutant concentration estimates for an Environmental Impact
Assessment for the Vail Timber Ridge project at 1280 North Frontage Road, West Vail. Except for
PM14, local air monitoring data does
not exist for Vail.
Therefore, I have developed best estimates based
on other data our agency has. The estimates and the basis for each are given in the Table below.
Pollutant Averaging Time
Standard
Estimate
Data Source
PM18 Annual Mean
50 ug/m3
15 ug/m3
Vail, 1996, 1999, 2000.
24 Hour Second
150 ug/m3
35 ug/m3
Maximum
PM2.s Annual Arithmetic
15 ug/m3
9 ug/m3
Grand Junction, 2003- 2006.
Mean
98`b Percentile
35 ug/m3
24 ug/m3
Of 24 Hour Averages
Lead Running 3 -month
0.15 ug/m3
.0092 ug/m3
Denver Municipal
Average
Animal Shelter, 2007 -2008.
NO2 Annual Mean
.053 ppm
.016 ppm
Woodmen Exit in
Colorado Springs,
2003, 2005 —2006.
CO I Hour Second
35 ppm
4 ppm
Grand Junction, 2004 -2006.
Maximum
8 Hour Second
9 ppm
2 ppm
Maximum
1
0
0
0
Pollutant Averaging Time Standard Estimate Data Source
SO2 Annual Mean .030 ppm .002 ppm Woodmen Exit in
Colorado Springs,
2003, 2005 —2006.
3 Hour Second
.500 ppm
.025 ppm
Maximum
24 Hour Second
.140 ppm
.013 ppm
Maximum
Ozone Old Standard
.12 ppm
.081 ppm Rifle, 2008.
1 hour 2nd
Maximum
New Standard
.075 ppm
.066 ppm
8 Hour Fourth
Maximum
Please note that these values are conservative indicators of ambient concentrations developed for
internal use by the Division in initial screening models for permit applications. They are not suitable for
applications beyond that scope of use. The Ambient Background Concentration summary values were
generated through an analysis of the ambient monitored data that are available to the Division. The
quantity of data is sometimes limited and may be of uncertain quality. Therefore, the ambient
concentration background values do not necessarily represent quantitative indicators of ambient air
quality and should not be used in instances where such information is necessary. The Ambient
Background Concentrations -
' 1. Do not necessarily substitute for on -site monitoring data.
2. Indicate the ambient pollution levels in general geographic areas, not a specific location.
This is particularly true for particulate concentration values.
' 3. Are subject to change without notice as new information is acquired.
When the Ambient Background Concentrations are to be quoted outside of Division use, they
' should be accompanied by an appropriate citation indicating their source and their limitations.
Referencing this letter would be adequate, but an expanded explanation is suggested.
I hope this information is useful. If you have further questions, I can be reached at 303 -692-
3226.
CABackground Conc\Vailabc.doc
Since�reyl9ya,
Nancy b. Chick
Environmental Protection Specialist
Air Pollution Control Division