EPA-908/5-77-003B
ATTACHMENT TO
FINAL ENVIRONMENTAL IMPACT
STATEMENT
UPPER EAGLE VALLEY AND VAIL
WASTEWATER FACILITIES PLAN
OCTORER 1977
U. S. Environmental Protection Agency
Region VIII
Denver, Colorado
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//7MJO
ATTACHMENT TO
FINAL ENVIRONMENTAL IMPACT STATEMENT
UPPER EAGLE AND VAIL WASTEWATER FACILITIES PLAN
Prepared by
U.S. Environmental Protection Agency
Region VIII - Denver, Colorado
October 1977
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TABLE OF CONTENTS
Chapter Page Number
I. THE EXISTING ENVIRONMENT 1
Introduction 1
Water Quality Goals, Policies and Current
Policies 2
The Social Environment 11
The Biological Environment 35
The Physical Environment 48
Existing Facilities and Flows 70
II. THE ALTERNATIVES AND THE PROPOSED ACTION 83
The Alternatives Evaluation Process 83
Description of Alternatives 84
The Selection of a Preferred Alternative 93
III. ENVIRONMENTAL IMPACTS 106
Primary Impacts of the Proposed Action 106
Impacts of Growth Associated with
Wastewater Facilities 127
Air Quality Impacts 133
Impacts on Water Quality from Nonpoint
Pollution 138
IV. MITIGATION MEASURES 143
Biological Mitigation Measures 143
Physical Mitigation Measures 147
Social Mitigation Measures 152
V. FINANCIAL CONSIDERATIONS AND IMPACTS 159
Rates and Charges 159
No Federal Financing - No Action Alternative 161
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VI. IRREVERSIBLE AND IRRETRIEVABLE COMMITMENTS
OF RESOURCES 164
VII. THE RELATIONSHIP BETWEEN LOCAL SHORT-TERM USES
OF MAN'S ENVIRONMENT AND THE MAINTENANCE AND
ENHANCEMENT OF LONG-TERM PRODUCTIVITY 166
The Social Environment 166
The Physical Environment 166
The Biological Environment 166
Glossary 168
Appendices
A-Other Federal Water Quality Programs A-l
B-Population Projections-Methodology and
Definitions A-5
C-Air Quality A-16
D-Common and Specific Names of Plant Species A-25
E-Common and Scientific Names of Terrestrial
Wildlife Species A-30
F-Common and Scientific Names of Birds A-33
G-Macro-Invertebrate Abundance A-41
H-Aquatic Animal Species A-45
I-Explanation of Bedrock Geology Units A-46
J-Explanation of Geologic Hazard and
Engineering Geology Map A-63
K-Explanation of Soil Classification -~-
A-81
L-Average and Extreme Discharges for USOS
Stations Located on the Eagle River and
its Tributaries
M-Summary of Current Discharge Permit
Limitations A-8?
N-Analysis of Recommended Sewage System
Improvements for Red Cliff A-83
Bibliography
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I. THE EXISTING ENVIRONMENT
INTRODUCTION
The purpose of this report is to present the possible environmental
impacts of a wastewater treatment facility plan for eastern Eagle
County, 120 miles (193 kilometers) west of Denver, Colorado. The
Environmental Protection Agency (EPA) has, in conformance with the
National Environmental Policy Act, prepared the following Environ-
mental Impact Statement (EIS). The proposed federal action is
the award of an EPA grant for partial funding of wastewater treat-
ment works in Eagle County. This option must be weighed against
a no action alternative (no EPA funding), as well as compared to
other possible solutions.
In 1972 Congress passed amendments to the Federal Water Pollution
Control Act establishing national water quality goals. The Act
included two parts: first, it provided for grants to fund planning
and construction to abate water pollution and, second, it provided
for the regulation of all point discharges through the National
Pollution Discharge Elimination System (NPDES). Each discharge
permit, contains limitations which reflect standards established
by EPA and/or the states. In addition, the Act provided federal
monies for areawide water quality management under section 208.
The emphasis of the 208 planning program is on control of non-
point pollution sources as well as point source pollution, the
latter being the principal subject of this environmental statement.
Presently, the Northwest Colorado Council of Governments is develop-
ing a 208 plan for the counties of Pitkin, Eagle, Summit, Grand,
Jackson, and Routt. A draft 208 water quality management plan for
these counties is expected to be completed during the fall of 1977.
The selection of eastern Eagle County for 201 Step 1 (Planning)
funding was made on a priority basis by Colorado. Priority rank-
ing for projects is made in Colorado by the Executive Branch and
is dependent upon existing and potential water quality problems,
and severity- The eastern Eagle County study area received a
priority ranking of 36 in 1975 and was approved for a FY76 201
Step 1 grant. The study area includes three sanitation districts,
the Vail Water and Sanitation District(VWSD), the Upper Eagle
Valley Sanitation District (UEVSD), and the Red Cliff Water and
Sanitation District (RCWSD).
The geologic location of the study area is the southern Rocky
Mountain physiographic province, between the northern end of the
Sawatch Mountain Range and the western flank of the Gore Range.
The boundaries of the Upper Eagle Valley Sanitation District, and
the Vail and Red Cliff Water and Sanitation Districts comprise
much of the private land along Gore Creek and the Eagle River.
The districts are surrounded by National Forest lands. The
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general location of the study area and the boundaries of these
districts are shown on the accompanying Figures 1 and 2
The existing environment within the study area is described in
this chapter under the headings of:
- Water Management Goals, Policies and Current Projects
- The Social Environment
- The Biological Environment
- The Physical Environment
- Existing Facilities and Sewage Flows
WATER QUALITY GOALS, POLICIES
AND CURRENT PROJECTS
The purposes of this section are to:
- Review and summarize applicable federal, state and local
statutes, plans and policies
- Describe current water quality management projects
Water Quality Management Laws, Plans, and Policies
Existing statutes affecting this 201 facilities plan are summa-
rized below:
Federal Water Pollution Control Act Amendments of 1972 — The
primary goals of the Federal Water Pollution Control Act of 1972
(Public Law 92-500) are: by 1983, achieve, wherever possible,
water that is clean enough for recreational uses and the protec-
tion of fish and wildlife; and, by 1985, completely eliminate the
discharge of all pollutants into the nation's waters. The law
stipulates a series of steps with strict deadlines and enforce-
ment provisions. The Act is administered by the Environmental
Protection Agency (EPA); however, with EPA approval, responsi-
bility for implementation of certain portions has been delegated
to state agencies. In Colorado, the Water Quality Control Com-
mission of the Colorado Department of Health (CDOH), acts as
the state delegated agency.
The Act authorized federal grants for 75 percent of the planni
design and construction costs of new or improved sewerage facil
ties. Facilities plans must conform to state planning programs*"
as well as other water quality programs established in other
sectionsof the Act (e.g., Sections 208 and 303 (e)) .
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ONAl
>O«ST
IGRAND
NATIONAL --...~
UPPER EAGLE VALLEY SANITATION DISTRICT
VAIL WATER AND SANITATION DISTRICT
REDCLIFF WATER AND SANITATION DISTRICT
ENVIRONMENTAL IMPACT STATEMENT
FOR A 201 FACILITIES PLAN
LOCATION MAP
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Figure 2
TOWN OF VAIL
T
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Section 208 provides for the implementation of areawide waste
treatment management planning. Within designated 208 planning
areas, 201 facilities plans represent one component of the more
comprehensive 208 plan. The study area is within the Eagle-
Piney Subbasin, which is within Colorado Planning and Manage-
ment Region XII, a designated 208 planning area.
Section 303(e) of the Act specifies that each state shall have a
continuing planning process for the maintenance of the quality
of all waters within its boundaries. This section requires
water quality management plans to be prepared for designated
entire river basins within a state. A primary purpose is to
evaluate present water quality and specify water quality objective:
to be achieved in the basin, providing a basis for establish-
ment of waste discharge requirements and wasteload allocations
for streams. Another purpose of basin planning is to recommend
regional and local planning areas for waste management and
facilities planning under Sections 208 and 201 of the Act. The
study area is located within the Colorado River Basin, and the
303 (e) Basin Plan for this area has been completed. The plan,
published by the CDOH, serves as the foundation for regulating
all activities which could potentially affect water quality.
Wasteload allocations have been established for surface flows
in the Eagle-Piney Subbasin.
The Act establishes a system of permits for waste discharges,
replacing the Refuse Act permit program of 1899. The National
Pollutant Discharge Elimination System (NPDES) is administered by
the individual states, with EPA approval. In Colorado, the
NPDES program is administered by the Water Quality Control Com-
mission of the CDOH, under the State Water Quality Control Act.
Colorado Water Quality Control Act — The Colorado Water Quality
Control Act (SB 390, 1973) provides a foundation for maintaining
control of water quality within Colorado and in carrying out the
objectives of the FWPCA. It created the Water Quality Control
Division and the Water Quality Control Commission within the
CDOH. Duties of the Commission include adoption and revisions of
state water quality standards and a revised stream classification
system. Waste discharge standards, wasteload allocations and dis-
charge permits are administered by the Division.
In August 1975, the present waste discharge standards were adopted.
Stream segments have been classified as either "water quality
limited" or "effluent limited." On effluent limited streams,
permits are based solely on the state discharge standards. On
water quality limited streams, permits are more restrictive since
the state water quality standards would not be maintained with only
the standard limitations. In these situations, the amount of each
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pollutant discharge allowable (wasteload allocation) is determined
in basin water quality management plans. (The Commission may also
adopt additional discharge standards for pollutants not included
in the original standards.)
Colorado has adopted an anti-degradation policy toward the quality
of state waters. Waters which presently are superior in quality
to the established standards shall be so maintained, where econom-
ically feasible. Other federal and state water quality programs
are discussed in Appendix A.
Colorado Waste Discharge Standards — In accordance with PL 92-500,
EPA published minimum effluent requirements for secondary treat-
ment, shown in Table 1 on the following page. Individual states
may impose more stringent limitations.
In January 1973, under provisions of the Colorado Water Quality
Control Act, Colorado adopted effluent discharge standards which
were more rigorous than those of EPA, with respect to BOD and SS,
and more extensive. The regulations required all treatment plants
to be producing effluents with BOD and suspended solids concentra-
tions of 20 mg/1 or less by 1978. It was later determined that
these standards could not be attained by 1978, due to lack of
financial assistance to provide the necessary improvements.
A revised set of effluent discharge standards became effective in
August 1975, as shown in Table 2 on the following page. Current
discharge permits reflect these requirements, unless more stringent
criteria are required to maintain water quality standards of
the receiving stream. The Eagle Piver and Gore Creek are water
quality limited streams — they cannot meet the B.. classification
without more restrictive waste discharge limitations than the
minimum recommended above.
Colorado Water Diversion Projects
Table 3, on the second following page, gives -a summary of the current
water diversion projects which will potentially divert water from
the study area. The Homestake Project already diverts water from
the Upper Eagle drainage basin and plans are being formulated for
additional water exportation. The Eagle Piney/Eagle Colorado
Project is another project which may eventually cause the exportation
of additional water from this basin. Exports of water are totally
consumed in that water is not returned to the stream from which
diverted. Due to the fact that wasteload allocations for water
quality requirements are based upon stream flows, the potential
effects of these projects are presented. A study has been under-
taken by the various water and sanitation districts in the area to
further evaluate these potential depletions. The proposed projects
are illustrated in Figure 3, following Table 3. J
The Homestake Project is a joint venture trans-mountain diversio
project for the cities of Aurora and Colorado Springs. Phase i
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TABLE 1
EPA MINIMUM EFFLUENT REQUIREMENTS FOR SECONDARY TREATMENT
Parameter Unit Value
7-day average 30-day average
1. Biochemical oxygen demand (BOD) mg/1 45 30
(five-day) *•
2. Suspended solids (SS) mg/1 45 30
3. Fecal coliform2 No./lOO ml 400-12,000 200-6,000
4- PH 6.0 to 9.0
NOTES: 1 85 percent removal is also required; in the case of a dilute influent.
this requirement may be more restrictive than the effluent limitation.
2 Geometric mean; minimum recommended requirements are 400/ml and 200/ml,
however, depending upon temperature and streamflow and other critical
conditions, the less stringent requirements shown in the table may be
imposed.
TABLE 2
COLORADO WASTE DISCHARGE REQUIREMENTS
Parameter Unit Value
7-day average 30-day average
1. Biochemical oxygen demand (BOD) mg/1 45 30
2. Suspended solids^- mg/1 45 30
3. Fecal coliform2 No./lOO ml 400-12,000 200-6,000
4. Residual chlorine mg/1 less than 0.5
5- pH 6.0 to 9.0
6. Oil and grease 10 mg/1 and there shall be no visible sheen
NOTES: 85 percent removal is also required; for a dilute influent, this re-
quirement may be more restrictive than the effluent limitation.
2 Geometric mean. "Whatever is necessary to protect the public health in
the stream classification to which the discharge is made." A scale is
used depending on stream class and characteristics.
SOURCE: Colorado Department of Health
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PROPOSED WATER DIVERSION PROJECTS
IN THE STUDY AREA
Project
Benefactors
Status
Source(s)
Appropriations
/Effects
Homestake Water
Diversion Project
Cities of Aurora
Colorado Springs
Two Parts - Homestake
and Eagle-Arkansas
Divisions
oo
Homestake Division
Phase I complete/
Homestake Dam & Reservoir
(joint undertaking Aurora,
Colorado Springs, Colorado
River Water Cons. Dist.)
Phase II not complete
Essentially would be an
expansion of the above
Includes Iron Mountain Dam
below Homestake Reservoir
Arkansas Division
Iron Mountain Reservoir
Eagle River tributaries-
Fancy, French, Sopris,
Missouri
Homestake Creeks
Upper Eagle River tribu-
taries - Cataract, Piney,
Fiddler, Mitchell and
East Fork of Eagle River
USGS predicts annual loss of
34,600 acre feet per year
when complete from Homestake
Creek
Water rights adjudicated in
1962 appropriated in 1952
Phase II would divert up to
31,100 acre feet per year
Potential annual diversion of
8,300 acre feet per year
Eagle-Piney/Eagle
Colorado project
Denver Water Board
Still in planning stages
Stage I - Piney Reservoir
and transcreek diversion
tunnels
Stage II and III - (con-
struction on drainages out
of study area ) Eagle
Colorado Dam
Stage IV - diversion facili-
ties on Upper Eagle
Export from Eagle and
Piney River Drainages
Bighorn, Pitkin, Booth
Middle, Red Sandstone
and Black Creeks
Piney River
Resolution Homestake
Turkey Lime & Wearyman
Creeks
Upper part of Eagle River
Water rights adjudicated in
1962, appropriated in 1956
Stage I- 35,500 acre ft. per yea
Stages I & III None
Stage IV -17,900 acre feet
per year
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I
^
I
Legend:
Figure 3
EXISTING a PROPOSED
TRANS-MOUNTAIN WATER DIVERSION PROJECTS
Sfr-
*fi£T
J
HOMESTAKE I PROJECT
HOMESTAKE H PROJECT
EAGLE-PINEY/EAGLE-COLORADO PROJECT
EXISTING RESERVOIRS
PROPOSED RESERVOIRS
HOMESTAK/E
RESERVOIR
To South
Plotte River
SOURCE: REF. Nos. 84,108
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the Homestake Division, is complete; Phase II, the Eagle-Arkansas
Division is in the planning stage. Phase I, accomplished in 1967,
includes the Homestake Dam and Reservoir, on Homestake Creek.
Water is transported through Homestake Tunnel to the eastern slope
where it is stored in three reservoirs.
USGS records indicate an annual diversion of 34,600 annual acre
feet (42.7 cubic meters) from the project. Expansion (Phase II)
of the Eagle-Arkansas Division involves construction of the Iron
Mountain Dam below Homestake Reservoir. Stored water would be
pumped to Homestake Reservoir for distribution. Phase II would
divert an additional 31,000 annual acre feet.
The Eagle Piney/Eagle Colorado Project would export water to the
Denver metropolitan area through Dillon Reservoir and the Roberts
Tunnel Collection System. Construction is envisioned in four
stages: Stage 1, Gore Creek and Piney River tributary diver-
sions; Stages II and III would affect drainages outside the study
area; Stage IV,diversion and transmission of Upper Eagle River
basin drainages. (Stage II would transport water from the Eagle
Colorado Reservoir.)
The potential effects of these projects on streamflow in the study
area are such that a maximum of 92,000 annual acre feet could be
exported upstream from the Cross Creek confluence. In essence,
the annual Eagle River yield at Red Cliff could be exported. The
annual yield of Gore Creek would be substantially affected by the
Eagle Piney/Eagle Colorado Project.
Since wasteload allocations are based upon historical flows, a
further reduction would have detrimental effects on the capacity
of the streams to support fish life in various reaches. However,
the extent to which streamflow would be affected can only be
determined if the diversion periods and rates are established
for the pro-iects, and these are, to date, unknown. Estimating
flow rates at most locations on streams in the study area is not
feasible due to the sparse distribution of stream gauging stations
and associated records. In addition, diversion periods tend to
vary annually, being governed by the seniority of the water
rights, the availability and senior demand for water, and other
diversion stipulations included in agreements with government
agencies. Therefore, the expected effects of water exportation
on streamflow cannot be accurately predicted. However, legal
controls will probably be invoked to ensure that a desired level
of streamflow is maintained.
The water rights of both projects are relatively junior, due to
their late adjudication dates. Consequently, these projects
present no probable harm to most other appropriators. Most
diversions made under junior rights, such as the Homestake I
diversions, usually must be made and stored during the heavy run-
off period occurring with spring snowmelt. The Homestake I pro-
ject, in agreement with the Bureau of Land Management, is allow d
to divert only during the months of April through August. Pro-
visions for insuring flows through priority rights and statutes
are discussed further in the mitigations section.
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THE SOCIAL
ENVIRONMENT
Population and Population Projections
Population and Land Use -- The existing populations within the
study area comprise the major population centers of eastern
Eagle County and 65 percent of the total countywide population.
The following table summarizes current estimated population
distribution. The location of the population centers named
in the table was shown in Figure 2 on page 4.
TABLE 4
1975 ESTIMATED EASTERN EAGLE COUNTY PERMANENT POPULATION1
Population Centers Population
Vail2 (east and west) 4,000
Minturn Valley 1,500
Red Cliff 700
Gilman 350
Unincorporated area (Avon,
Beaver Creek and Eagle-Vail) 650
TOTAL 7,200
NOTES: •'-Permanent population for the purpose of this
report is defined as permanent residents who
live in the area for at least a season (winter -
5 months, summer-7 months)
2The average of both summer and winter projec-
tions, 4,000, is utilized to estimate year-
round population. Vail has high variances in
summer vs. winter permanent population due to
job seasonality- Summer population is estima-
ted as 70 per cent of winter population. Min-
turn and the Avon area experience some fluc-
tuation which is small by comparison. Although
permanent population levels are relatively low,
the area has a large visitor population.
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The existing populations, both permanent and visitor, are pre-
dominantly recreation-oriented. The Vail ski area, established
in 1963, has influenced the study area growth and has produced
the major population fluctuations. Average winter visitor
population is 9,700 persons; average summer visitor population
is 3,000 persons.
Within eastern Eaqle County most jobs are associated with the
recreation influence of Vail. Over 80 percent of the total jobs
are in the transportation, construction trade, services and
public administration sectors. Agriculture and mining employ
three and eight percent, respectively; finance, insurance and
real estate accounted for eight percent during the 12-month
period, 1974. The fluctuation in employment and unemployment
is seasonal. In 1974, the summer (May-Nov.) employment was 82.5
percent of the winter. Unemployment levels in the County rose
from 4.0 percent to 4.5 percent between the winter and spring
quarters.
Eastern Eagle County has developed from a ranching and agricul-
tural area to an essentially recreation-oriented area. Land use
has been influenced by ski area development since 1963, and
much of the agricultural land has been taken out of production.
Access is provided by Interstate 70 (1-70), an east-west
interstate highway system. One segment of 1-70 will soon be com-
pleted over Vail Pass, to the west of the study area.
East Vail, from the eastern boundary of Vail at the foot of Vail
Pass to the golf course, is a low-density, residential area of
single and multi-family dwelling units. This area experiences
severe climatic conditions, and steep slopes place some of this
area in avalanche paths. It is not an area of high development
pressure.
Between the golf course and Vail Village there are a few single
family residences and a few high density condominium develop-
ments near the west end of the course. This area is recreation/
open space in character.
Vail Village and Lionshead are the two commercial centers. The
Village is older, and more densely developed, with many multi-
family units (condominiums) mixed with lodge units (both rental
condo and motel type), and commercial businesses, restaurants
and shops. Lionshead is connected to the Village by pedestrian
ways, bicycle paths and a mini-bus system. Vail is pedestrian-
oriented; cars are restricted from the centers, with the maior't
of parking provided along the fringes. -1 y
Separated from Vail proper by the Interstate system (1-70)
is the strip development, which continues north and south of
1-70 from Lionshead west. This area contains condo-lodge type
development for approximately a mile, then the south face of
the mountain drops back, and an area known as West Vail opens to
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single family dwellings interspersed with multi-family units.
Parts of West Vail have been annexed, most recently the Lions-
ridge and Sandstone development areas.
The Interstate from West Vail to Dowds Junction winds through a
steep canyon, limiting the area's use, and no development occurs
until the junction is reached. Sprawling, single-family resi-
dential development and trailers are characteristic of the
Minturn Valley. The community of Minturn has an old commercial
center, where development begins close to the stream bed and
continues on the southwest slopes. Minturn developed in a linear
pattern paralleling the Eagle River and Highway 24 which bisect
the town. The Denver and Rio Grande property north of town was
annexed in 1974. An estimated 50 percent of the properties in
Minturn are rental, and 34 percent of the total are listed in
poor condition. Light industries include a concrete company,
a lumber yard and a batch plant.
Red Cliff, a small community south of Minturn, houses mostly New
Jersey Zinc Corporation employees. Most residences are single
family or duplex. Less than 200 residences are found in Red
Cliff.
Between Dowds Junction and Avon, the Upper Eagle Valley opens to
uncultivated agricultural lands, which are subdivided. The
Eagle-Vail subdivision has several single and multi-unit build-
ings, tennis courts and a golf course. The Benchmark development
has completed a shopping center. Some employee apartments have
also been completed which are part of the overall development plan
Beaver Creek, the third subdivision including a major ski area
had not begun development as of the Winter of 1976. Beaver
Creek has secured the necessary Forest Service permits for the
ski area, considered to be the necessary economic determinant to
ensure the success of all three subdivisions as planned. Cur-
rently a general store/post office/gas station and mobile home
park development exist in Avon.
Arrowhead, adjacent to Beaver Creek, is a second planned ski area
development, on private rather than public land. Two golf
courses, tennis and equestrian trails are part of the overall
plan. Area realtors project that Beaver Creek will be developed
more rapidly than Arrowhead.
Population and Land Use Projections — Future population and land
use projections were developed for the 201 planning effort. The
accomplishment of these projections was based upon: public
acceptability, local knowledge, acceptance by local planning and
government officials and the adaptability for use in other plan-
ning efforts. One constraint in developing 201 projections was
the on-going effort to accomplish 208 planning. As part of a
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large, six county 208 study, Eagle County projections for both
efforts had to be prepared concurrently. The Eagle County Plan-
ning Office (ECPO) had the responsibility for the preparation of
the 208 projections. Because the 201 planning effort and
schedule would have been delayed without the necessary future
service area/needs projections, EPA authorized the 201 effort
to proceed ahead of the 208 planners with the stipulation that
the figures be adopted by the 208 planning staff of the ECPO.
Development of the 201 projections included a number of interviews
and thus much local knowledge as to historic growth in Vail and
current planning efforts was obtained. Also various ratios
(e.g. number of visitors to available accommodations), and other
available population projections were used. Future trends were
developed based upon the assumptions (population influencing
factors) given in Table 5 on the following pages. The methods
and definitions are explained in depth-in Appendix B .
The assumptions resulted in three profiles for development, which
have been labeled high, medium, and low. The results of these
profiles and projections are given in Table 6 following Table 5.
The projections were presented in the spring, 1976, to the 201
Advisory Board and the UEVSD and Vail Sanitation District
Boards, the Eagle County Planning Commission (ECPC) and the
public. The ECPC adopted the high figures for Beaver Creek,
the moderate for Vail and Arrowhead, and the low for Minturn,
now referred to as the 201 adopted projections. In the fall,
1976, the ECPO revised the projections to reflect new data and
input from the 208 planning effort, such as a Vail housing
survey. The results, compared in Table 7, following Table 6,
reflect, in brief:
- Eastern Eagle County population is expected to more
than double by 1995
- Most of the new population is expected to locate in
the Avon/Beaver Creek/Arrowhead area
- The magnitudes of growth in both the 201 and 208 pro-
jections agree in 1985 and are within four percent
in 1995
- The location of growth in the 201 and 208 varies in
that ECPO placed more population, 2,000, in Vail
and placed some of the Beaver Creek allocation in
Arrowhead. (Neither of these two factors substan-
tially affects the planning for sewerage facilities).
Within the Gore Valley virtually all of the developable land
has been either platted or zoned. Zoning now exists for more
than double the number of present units. Due to recent
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TABLE 5
COMPARATIVE ASSUMPTIONS UTILIZED
FOR
THE POPULATION PROJECTIONS
LOW GROWTH PROFILE
BASIC CONDITIONS
FAVORABLE OR UNFAVORABLE
TO THE OVERALL AREA
DEVELOPMENT
Completion of 1-70 and the Second Bore of tunnel.
Competition from other areas in both other counties
(day skiers) and other states (destination skiers).
Continued unfavorable tax breaks on second homes.
Aggressive growth management by the town of Vail.
New akl area development is delayed.
CORE VALLEY
Vail and West Vail
(including Bighorn)
Expansion of mountain capacity to 11,000 (14,000
peak) peak not reached before 1985 Downzonlng of all
new developments, town cores (Vail-Lionshead) do not
receive higher density zoning. Moderate growth of
West Vail - the condominium market absorption rate for
Vail area affected by Beaver Creek, slowing to 100
new units per year until 1985, 100-150 units per year
till 1995. Little development in Bighorn Area.
AVON/BEAVER CREEK
(Benchmark, Beaver Creek
and Eagle-Vail with some
fringe growth)
Start Date of development, spring 1980 or 19R1;
Competition from other areas affects rate of growth,
and "total" development is reached in 1995. Future
reduction in the total units for the 3 developments occurs,
3000 units are built by 1990 (and 4500 units by 1995).
(Ski visitor and summer visitor growth continue to expand
in Colorado in this profile and the moderate/high pro-
files.) For low growth, the expansion is moderate.
Skier capacity is 7500-peak 9,000.
ARROWHEAD SKI AREA
(Development located
west of Beaver Creek)
Under a low growth profile for the Arrowhead ski area
the project would be unsuccessful in obtaining financing
and development is not begun during the planning period.
MINTURN
Minturn accommodates 10 oercent of new recreational
employment and their families, under low growth
for each area.
RED CLIFF
New Jersey Zinc Corporation either reduces drastically
or closes operations in Gypsum.
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Table 5 continued
MODERATE GROWTH PROFILF
BASIC CONDITIONS
FAVORABLE OR UNFAVORABLE
TO THE OVERALL AREA
DEVELOPMENT
Complet on of 1-70 and tunnel. Competition for destination skiers in
ether slates does not affect Colorado skier market drastically, although
overall skier visitor growth is not comparable to Vail growth to date
(which s now at 18 percent per year average). The summer visitor
market .xpands. Continued unfavorable tax breaks on second homes spurs
the development of more lodge units. No delay for new ski area development,
dlthoufli financing may be difficult to obtain.
CORE VALLEY
Vail and West Vail
(Including Bighorn)
Lxpdfsion of mountain capacity to 11,000 (14,000 peak). The peak is
rr,-,(iied (15 davs per season) in 1982. (Marketing of off peak weekHavs
an. differential pricing mav occur to lessen peaks.) Peak Day skier
oemand totals exceed the combined areas; capacities by 1990 necessitating
forest Service and Ski Developer rooperation in limiting ticket sales
and finding solutions. Downzoning of all neu developments occurs.
Town core areas are granted higher densities based upon demonstrated
economic need. Crouch takes place in West Vail, the market absorption
rate for Vail area expands in 1983, in 10 years 1000 new units are sold
and between 1990-1995, 500 new units. A lod«e and few units ?re huill
in Bighorn.
AVON/BEAVER CREEK
(Benchmark, Beaver Creek
and Eagle-Vail with some
fringe growth)
ftart date of developrent. Spring 1978. Total development is reached
ir 1995, however, due tc future downzoning the total is reduced from
7180 to 5500-6000 units (market absorption rates could also affect this
reduction). By 1990 4,400 units are built, and by 1995 new units total
6000. (The market for lodge units will affect the condominium mix and
therefore more high occupancy units could he build.) The moderate profile
projects as nany total units in Beaver Creek/Avon in 13 years as Vail
has today after 13 years of growth, supporting a smaller mountain. The
skier capacity of 7500 (9,000 peak) is reached ir 1993-94 and after that
year the Forest Service could allow expansion or require the limitation
of ticket sales.
ARROWHEAD SKI AREA
(Development located
west of Beaver Creek)
Start date of development, Mh'-.si. Cumin.-1 i t inn I rum nther .ire.is .ill.-rt*
the rate of growth, however, 60 percent of the total planned Arrowhead
development is reached by 1995. Future downzoning is projected to occur
and total estimated units allowed, 2000, would not all be built until bevond
the study period. Total skier capacity. 4800 (6000 peak). Arrowhead's
share of the condominium market is approximately 25 percent, if current
tiends continue.
MINTURN
Minturn attracts 10 oercent of recreation related new population
under moderate growth for the area.
RED CLIFF
moderate assur.ptinns were made.
-16-
-------
Table 5 continued
HIGH GROWTH PROFILE
BASIC CONDITIONS
FAVORABLE OR UNFAVORABLE
TO THE OVERALL AREA
DEVELOPMENT
Completion of 1-70 and tunnel. Skier visitor and summer recreation industry
expand, and the market is favorable for the rapid growth of new ski area
development. The second home market is not affected by fewer tax breaks,
the overall economy makes gains and the expanded influx of outside U.S.
investments to the Vail area all promote development.
GORE VALLEY
Vail and West Vail
(Including Bighorn)
Expansion of mountain capacity to 14,000 peak (peak reached in 1983)
(marketing could "even out" the peaks) however, the Forest Service and
ski developers must limit sales on weekends and seek alternative solutions.
Less downzoning of new development than the present trend of 50 percent.
Town core areas receive higher density zoning. Much of the new growth
takes place in West Vail. Market absorption rate continues to be between
200-300 new units per year (could be higher, if not for the competition
from new ski areas). A lodge and condo units are built in Bighorn. In
total, 3000 new unics are sold from 1976-1990 and 900 more between 1990-
1995. Also some new low rent (employee) units are built.
AVON/BEAVER CREEK
(Benchmark, Beaver Creek
and Eagle-Vail with some
fringe growth)
Although Avon area developers project build-out to 7180 units by 1990,
neither current trends, Vail historical growth or the ski industry
projections support such astronomical growth. In the high growth profile,
total development could be reached in 1995 if the Vail growth rates were
duplicated (Vail was built during more favorable economic conditions) and
If either the mountain capacity was expanded or If low occupancies in
new units were realized. By 1990, 5500 units are built and by 1995, 7000
units. At this time, peak day skier demand could be as high as 12,900 skiers
even if many units were low occupancy, private condos, and higher if
the high to low occupancy ratios were split 50/50 as in Vail today. Peak
skier capacity In Beaver Creek (9000) begins to be exceeded by 1991.
ARROWHEAD SKI AREA
(Development located
west of Beaver Creek)
Development begins in 1979 and attains 90 percent of full developer
projections by 1995, or 2970 units. The rate of development is accelerated
as at Beaver Creek; although these two areas are in competition and one
area's capture of the market may affect another's share. By 1990 over 2000
units are built. If added to the Beaver Creek unit, 8000 total units are
built, and if added to Vail 11,000 units. Market absorption rates under
high profiles for all 3 areas, are 800-900 units per year, double the rate
of growth at Vail during the Initial time period.
MINTURN
Mlnturn attracts 10 percent of all new permanent
much of the transient construction force.
population and
RED CLIFT
The Iron Mountain Dam is built, and many construction workers move
to Red Cliff. The mine continues operation, perhaps opening a
new vein of zinc.
-17-
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TABLt t>
POPULATION PROJECTIONS FOR THE
GORE AND UPPER EAGLE VALLEY
LOW PROFILE ASSUMPTIONS
1975
1980
Population Estimates
1985
1990
Gore Valley
Permanent Population
Average Daily
Peak Day
Avon/Beaver Creek
Permanent Population
Average Daily
Peak Day
Arrowhead
Minturn Valley
Redd if £
199S
4 ,750
13,250
20,250
600
600
1,500
650
4,800
16,400
22,700
1,800
1,800
1,750
600
4,880
17,350
23,200
1,300
3,700
4,000
1,770
420
4 ,940
18,700
24,300
2,330
8,200
9,900
1,750
400
4,980
19,200
24,900
3,200
11,500
14,400
2,000
360
Totals (Average Dally)
16,000
20,550
23,240
29,050
33,080
MODERATE PROFILE ASSUMPTIONS
1975
Gore Valley
Permanent Population
fwer TQC D.T i ly
PC,ik Day
Vvon/Re,-"":' r '"reck
Her meat t'ri|jula L ion
Average- Daily
Peak Duy
Arrowhead
Permanent Population
Average Daily
Peak Day
Minturn Valley
RcdcliCf
1980
Population Estimates
1985
1990
1995
4
13
20
1
,750
,250
,250
f>00
600
,500
650
4
16
22
1
3
4
1
, 800
,400
,700
. 300
,900
,800
,880
700
5
19
24
2
6
9
1
2
1
1
,160
,000
,700
,000
,400
,300
300
,860
,260
,955
,200
5 ,
19,
26,
2,
10,
12,
3,
4 ,
1,
1,
430
580
500
900
000
700
600
770
320
920
200
5
21
27
4
15
IB
5
6
2
,660
,230
, 300
,200
,000
,500
975
,595
,340
,150
750
Tot.,Is (Average Daily)
16,000
22,900
30,400
36,500
44,700
HIGH PROFILE ASSUMPTIONS
1975
1980
r.ore V.i 1 ley
Permanent Population
Average Doily
PL-.ik Daily
Avon/Beaver Creek
Permanent Population
Average Daily
Peak Daily
Arrowhead
Permanent Population
Average Daily
Peak Daily
Minturn
Redd if f
Totals (Average Daily)
Population Estimates
1985 1990
1995
4,750
13,250
20,250
600
600
1,580
650
16,000
5.000
17.600
23.060
1.200
4,000
5,000
280
1,520
2,030
1,930
700
25,750
5,520
20,500
25,160
2,900
9,700
12,200
650
2,960
3,950
2,030
1.200
36,600
'.,020
22,500
27,520
3,900
13,900
16,700
1,280
4,500
6,800
2,190
1,200
44,300
6,440
24,170
31,800
4,900
18,200
22,800
1,780
8,300
10,500
2,400
750
53,800
The population prelections included estimates of:
estimated number of new }obs in the area
ates of: permanent population, based UDOn an
and the associated population; average da?lv
visitor population, based upon accommodations and occupancy; skier demand, based
historic skier to visitor ratios and peak population (winter) based upon histori Uf>°n
occupancy pe.iks and permanent population. For specific details, refer to Appendix^*1*
SOURCE: Camp Dresser 4 McKee Inc.
-18-
-------
TABLE 7
COMPVRISON OK ADOPTED 201 POPl'l.AnoN PROJECTIONS
Vail/Gore Vallev
Permanent
Average Daily
Peak Dav
Avon/Beaver Creek
Permanent
Average Daily
Peak Day
Arrowhe.nl
Permanent
Average Daily
Peak Dav
Minturn
Red Cliff
Totals:
Permanent
Average Daily
1975
ECPO 201 Adopted
4,750
16,820
560
1,227
537
7,078
19,150
4,750
13,250
20,250
600
1,500
650
7,500
16,000
) THE OCTOBER 1976 EAGLE COI'N1\ POPULATION PROJECTIONS
1980
ECPO 2
•4
18
1
5
2
1
8
27
,son
,370
,200
,000
280
,030
,880
600
,760
,880
0] Adopted
4,800
16,400
22,700
1,200
4,000
5,000
1,880
600
8,480
22,880
1985
ECPO 201 Adopted
5,160
19,920
2,900
8,000
650
3,550
1,960
420
11 ,090
33,850
5,160
19 ,000
24,700
2,900
9.700
12,200
300
! ,860
2,2hO
l.«>hO
420
10,740
33,140
1990
1995
ECPO 201 Adopted
5,430
21,460
3,900
11,500
1,280
6,000
2,050
400
13,060
41,410
5
19
26
3
13
16
3
4
2
12
39
,430
,580
,500
,900
,900
,700
600
,770
,320
,050
400
,380
,700
ECPO 201 Ad-
5,660
23,120
4,900
15,130
1,900
8,750
2,150
380
14,990
49,530
5
21
27
18
22
5
6
-t
14
47
optec
,660
,230
,300
,900
,200
,800
980
,600
,340
,150
380
,070
,560
Notes: 1, All numbers rounded to nearest 10.
2. Average daily population is winter onlv and includes visitor population.
3. Summer population averages are 30-60 per cent less than winter averages, due to the number of visitors.
4. The 201 adopted figures are similar to those of Eagle Countv revised in October of 1976 with the
following observations:
- The County Planning Office has allocated more population to Arrowhead and
less to Beaver Creek (the developments are adjacent).
- The County has projected Vail permanent population to be higher in all years
Sources: Eagle Countv Planning Office (ECPO); Camp Dresser & Mckcf 201 Population Analysis
-------
planning efforts by the town of Vail:
- Significant downzoning of recently annexed areas has
been accomplished through compromises with developers
- A growth management effort is being pursued
The projections of future land use in the Gore Valley were based
upon these efforts. In addition, continued low market absorption
rates with the advent of Beaver Creek would mean a lessening of
growth in the Vail area. A total of 2,800 new units are pro-
jected to be built between 1976 and 1995. Future development in
Vail Village is expected to be contained, with an infilling of
present commercial areas. West Vail will receive the strongest
development pressures, and Bighorn will receive less development
pressure than the other areas. Future generalized land use pat-
terns are shown on Figure 4/ on the following page. Present and
future land uses by percentages are given in Figure 5, following
Figure 4.
The Upper Eagle Valley area at Avon/Beaver Creek/Arrowhead is
projected to grow rapidly within the study period. The Beaver
Creek ski area will probably reach full development within each
of the subdivisions, a total of 7,100 units in 20 years. Sig-
nificant fringe area development was not projected due to the
assumed balance within market competition. If fringe areas
develop, they may tend to slow down the period of full develop-
ment projected for other subdivisions. The Arrowhead ski area
development which is evaluated as more speculative, is expected
to build 1600 units during the next 20 years.
Within the Arrowhead and Beaver Creek ski areas, golf courses,
equestrian trails and park areas will provide both summer and
winter recreational opportunities. Regional shopping center
facilities will be provided at Benchmark and industrial sites
at Eagle-Vail. Future land uses and development patterns are
given in Figures 4 and 5.
The largest developable area outside current planned development
boundaries is the Nottingham Ranch property which is adjacent
to Eagle-Vail across Interstate 70. A second developable area
is the corridor between Arrowhead and Squaw Creek. These two
areas are outside the sanitation districts' boundaries.
Minturn will grow due to its ability to provide less expensive
housing alternatives for the resort area employees. Growth
pressures will be lessened somewhat by the commitment of the pro-
moters of the Beaver Creek and Arrowhead developments to provide
on-site employee housing. Between 300-400 units are projected
to be built in Minturn during the 20 year period, nearly double
-20-
-------
UPPER EAGLE VALLET SAN-»T.ON DISTRICT
VAIL WATER AND SANITAT ON DISTRICT
REDCLIFF WATER AND SANIT4- ON DISTRICT
ENVIPONyENTAL -MPAC' S'A'EUEN
FOR A zoi r*C u ' E 5 =. ft1"
-------
Present a Projected
Percentage of Land Use
Projected
Percentage of Land Use
GORE VALLEY
AVON/BEAVER CREEK/
. ARROWHEAD
2940 acres, present
3300 acres, projected
(Open space 8 agricultural
not included.)
3430 acres
(Open space/recreational-ski areas
not included.)
SOURCE: Eagle County Planning Office
and Developer Estimates -2?-
FIGURF
-------
the present number. The location of these new units recom-
mended in the Comprehensive Plan is within the incorporated
town limits. Minturn's land use pattern is expected to become
more intense with potential industrial location on the recently
annexed railroad property. Red Cliff is not expected to chanqe
due to its relative remoteness and company town character.
Land Use Policies, Plans and Controls
Most of the land within the study area is privately owned. The
major exception is the Beaver Creek Ski Area which will be
developed partially within National Forest boundaries. It is
planned that this development will utilize the facilities of
the Upper Eagle Valley Sanitation District, and, accordingly,
the controls placed on its use will have a direct impact on
the study area. Also, the Bureau of Land Management (BLM)
manages several small parcels in the study area. A land ex-
change is being contemplated between the BLM and the owners of
the Benchmark property, since the northern portion of the Bench-
mark property, outside of the study area, is within an animal
migration route. In addition to these Federal agencies, local
and state agency plans and policies will influence land use.
Federal Land Use Plans — The Forest Service operates under
the Multiple Use - Sustained Yield Act of 1960 which provides
for the use of national forests for outdoor recreation, range,
timber, watershed, and wildlife and fishing purposes. Multiple
use management allows for special use permits which are a part
of overall Multiple Use Plans for every Planning and Management
Unit. The Meadow Mountain Planning Unit is composed of four
Management units, Grouse Creek, Holy Cross, McCoy and Beaver
Creek. Vail has a special use permit in the Upper Eagle
Planning Unit and the ski area is itself a management unit,
the Vail Mountain management unit. Ski lifts, trails and
restaurant facilities are permitted on the public land; base
facilities and accommodations are on private land. The Beaver
Creek unit was designated as a winter recreation sports site
and granted a special use permit similar to that of Vail.
The Forest Service reserves the right to (1) limit skier
capacity and (2) develop measures to limit the number of lift
tickets sold. The District Ranger is responsible for super-
vision of project construction and for ensuring that implemen-
tation takes place as specified in the special use permit.
Parts of the McCoy and Grouse Creek units have been designated
as roadless areas. Other parts are set aside for spring and
fall habitat, as migration routes for wildlife and for dispersed
recreational opportunities, such as hiking, hunting and cross-
country skiing.
-23-
-------
The BLM also provides for multiple use management. BLM land
in the study area is managed for such uses as livestock
grazing, recreation, open space and wildlife. The small
sections of BLM land within and near the study area are shown
in Figure 11 .
Local Government Land Use Controls — Eagle County reviews
plans for all subdivisions and developments. The County
Planning Commission has adopted a land use master plan which
includes future development patterns and growth policies,
goals and objectives.- The County plan contains a policy
statement expressing the intent to preserve the open, rural
character of the County while locating new high-density
residential growth in existing and planned centers. The
development of new commercial centers at West Vail, Avon/
Beaver Creek and Eagle-Vail have been approved and designated
in the County plan.
Sketch plans and preliminary plans were reviewed and accepted
and zone district, maps amended for all three subdivisions
in the early 1970's. Final plat plan acceptance by Eagle
County has been obtained by Eagle-Vail and Benchmark, and
Beaver Creek is expected to file in the winter-spring of 1977.
Vail and Minturn have local zoning ordinances. In addition,
Vail has a Design Review Board which has instituted strict
architectural controls. Currently the planning staff and
their consultants are developing a growth management plan,
which will probably become a guideline for overall develop-
ment and final plat approvals. The plan may enable the Town
to establish a method of evaluating both the economic need
and the economic impact of zoning changes, both for admitting
higher,and for requesting lower, densities.
The current trend is to contain growth and to down-zone
where feasible to minimize growth beyond desirable accommoda-
tion/visitor to mountain capacity ratios.
The town of Minturn has a master plan and zoning controls.
The plan recommends the continuation of a single family re-
sidential orientation; however, Minturn's proximity to the
resort areas will continue to bring development pressure
for lower-income employee multi-family housing.
State Controls — The state of Colorado has very limited
control over land use, primarily limited to offering coordina-
tion assistance for administering planning programs among
local governments through the Department of Local Affairs
In fact, the Colorado Land Use Act states that the decision
making authority as to the character and use of land shall be
made at the lowest possible level of government.
-24-
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Archaeology, Paleontology and Historic Sites
The area from Vail to Wolcott was examined in terms of:
- Existing archaeologic survey work
- Historic sites which are either presently on the
National Register of Historic Sites, proposed, or
potentially eligible for the Register.
The Office of the State Archaeologist examined the files which
would contain all archaeologic sites recorded for the area. None
of the archaeologic sites registered were within the existing
facilities sites or the existing interceptor line routes. However,
it should be emphasized that the Colorado Archaeological Survey
Site Inventory contains only recorded archaeological sites, hence
previously unrecorded--and possibly signifleant—sites could well
be present.
The National Register contained one registered historic site, the
Wolcott Stage Station, which is west of the study area in Wolcott.
No other nominated sites were found in the Federal Register which
publishes new and proposed sites every Tuesday. The State knows
of no potential sites in the area.
Recreational Facilities
Although the project impact area is a major destination resort center
with extensive ski, golf and tennis facilities throughout the area,
there are shortages of those facilities found in more conventional
residential communities such as parks, playgrounds, and walkways
outside of the developed town centers. On the other hand, there is
nearby access to public lands for hiking, camping, horseback riding,
fishing, and hunting. Within the direct project area, there are no
developed recreational facilities, except for two areas of public
access to fishing.
Air Quality
An investigation of present air quality in the study area and that
which could occur in the future, given the projected population
increases, was conducted. The basis for this evaluation was the
need to determine, to the extent possible, the potential for future
air quality maintenance problems.
Historical, meteorological and air quality data were obtained from
local sources. A box model was developed and used to project future
pollution from particulates.
Meteorology -- Meteorology or climate conditions may be examined on
a regional (macroscale) and local (microscale) level. Regional
characteristics include: a prevailing westerly wind which is gen-
erally upslope, higher wind speeds in winter than in summer, and
frequent large-scale stagnations when the western slope is dominated
by high pressure systems.
-25-
-------
Microscale meteorological conditions are important in determining
local air quality and conditions for the study area. The character-
istics of wind speed, wind direction and mixing depth determine air
pollution levels in the valleys of the study area. These character-
istics are discussed in Table 8, below. The meteorological patterns
recorded in Vail were characteristic of mountain valleys — upslope
and downslope winds are recorded within a 24-hour period and air
temperature inversions are frequent. As a conseauence of these
conditions, air pollutants are often trapped inside the valleys when
the temperature inversion lowers the mixing depth. Winter tempera-
tures are more often the cause of inversions than summer temperatures.
In the study area, inversions usually form at night and persist into
the morning. Strong inversions during regional air stagnations,
occurring with a lack of wind and solar radiation to break or dis-
perse the inversion, cause a severe curtailment of dispersion.
TABLE 8
METEOROLOGICAL VARIABLES AFFECTING AIR QUALITY
Variable
Wind Direction
Wind Speed
Mixing Depth
(or Height)
Air Temperature
Characteristic (s)
Upslope/Downslope winds-
Solar radiation heats air
during the day, causing
upward (upslope) air flow.
Nightime radiative cooling
causes downward(downslope)
air flow. Reversal in
wind directions can be
abrupt. Particularly ap-
parent when regional air
mass movement is weak
(sometimes called diurnal
variation).
High pressure systems can
cause wind stagnation.
Low pressure increases
wind speed.
Defined as distance above
which little dispersion
of pollutants occurs.
When the mixing height
is low, dispersion is
limited to the lower por-
tion of the atmosphere.
Cooling/Heating-Nightime
radiative cooling, daytime
solar radiation heating
Effects
Upslope/downslope winds
dominate the valley except
during periods when region-
al air mass movements
dominate valley climate.
Strong downslopes can push
pollutants into the valley.
Upslopes can clear the
valley by carrying pollu-
tants out of the valley
(confined) area.
Stagnation causes air to
be motionless, limiting
dispersion and increasing
pollution. Increased wind
speed facilitates dispersion.
Normal mixing height is
unlimited, except'during
an inversion, when it be-
comes limited, resulting
in high concentrations of
pollutants.
Cool, nightime air sinks
to bottom of valley, trap-
ping polluted air. Warm
daytime air rises, allowing
pollutant dispersal.
-26-
-------
Present and Historic Air Quality — In the study area, lonq, cold
winters result in extensive fireplace and fuel use which cause
hiqh concentrations of pollutant emissions. The valley con-
fiquration of the area and the associated mcteoroloqy freuuonHy
create poor conditions for pollutant dispersion. Thus pollutants
become "trapped" in the populated valleys. Poor dispersion
conditions and peak emissions tend to occur simultaneously in
winter.
Measurements of existing air quality in Vail have shown that
total suspended particulate concentrations have either approached
or exceeded state and federal standards since 1973. The standards
and monitored pollutants are given in Tables 9 and 10 on the
following page.
The state 24-hour particulate standard was exceeded on eight days
in 1973, five days in 1974, two days in 1975 (at two locations),
and in 1976 (one location). IN 1973 the federal 24-hour par-
ticulate standard was exceeded once, which is allowable, and
it was approached in all years. The state short-term and long-
term particulate standards are being exceeded but are within
allowable federal limits for both the short- and long-term stan-
dards. The locations of the sampling devices were the Vail Valley
Medical Center, Vail Associates Maintenance Building, and the
clubhouse at the golf course.
Only one year of data was available for carbon monoxide (CO)
emissions measurements. In the winter 1975-1976, CO data was col-
lected on a continuous basis by a non-dispersive infrared analyzer
located at the Town of Vail Municipal Building. In 1975 the state
and federal 8-hour standards, shown in Table 9, were met on a
single day, December 30, which is permissible. The graph of
emissions measurements for this day is shown in Figure 6 on the
second following page.
An Air Quality Model -- In order to calculate particulate con-
centrations and project them to future years, a mathematical model
which approximates the physical situation in the study area during
an air pollution episode was used. An episode is a period when
climatic conditions remain stable and are not conducive to dis-
persion. The model used was a multiple box model, a modification
of one developed by Marlatt, Holben and Renne in 1973. A total
of nine airsheds were identified whose box-like dimensions were
-27-
-------
TABLE 9
FEDERAL AND STATE PRIMARY AMBIENT AIR QUALITY STANDARDS
POLLUTANT FEDERAL STANDARD STATE STANDARD
Total Suspended Particulates Micrograms per cubic meter
Annual geometric mean 75
Annual arithmetic mean 45
24-hour average1 260 150
Carbon Monoxide Parts per million
8-hour average 9 9
1-hour average 35 35
NOTES :
1. Not to be exceeded more than once per year
Source: Section 109, National Ambient Air Quality Standards, 1970
TABLE 10
ANNUAL MEAN, TOTAL SUSPENDED PARTICULATES IN VAIL VILLAGE
YEAR GEOMETRIC ARITHMETIC
Micrograms per cubic meter
19731 55 71
1974 59 74
19752 48 61
NOTES;
1. Measured with a high volume sampler filtering device taken
for 24-hour periods every fourth day.
2. High for year was 245
Source: Marlatt and Gelinas, 1975r Town of Vail
-28-
-------
15-f-
14
13 -
12
o
Q_
10
9 -
8 -
7 -f
6 -
5 -
4 -
Carbon Monoxide Measurements
Taken December 30, 1975
HIGH 8-HOUR AVERAGE
1
1
night
~
1
1
6:OOA.M
1
1
Noon
1
1
6:OOPM
SOURCE Tcr/ri of
FIGURE 6
-------
limited by valley topography and mixing height. Mixing height
is the distance above which little dispersion of pollutants
occurs. The average cross-sectional parameters of the airsheds
and their locations are given in Table 11 and Figure 1 on
the following pages. Width is determined by the length along
the centerline of the valley floor. Height is the mixing
height. Theta 1 and theta 2 represent the angles at which the
valley walls rise, since the walls are not perpendicular to the
base.
The dispersion characteristics of the model require that the
concentration of pollutants within the box must be equal to
the difference between the pollutants emitted into the box, or
brought into the box from upwind, and the pollutants removed
through the downwind ventilation areas. Also, dispersion
within the box was assumed to occur immediately since the atmos-
phere in the box must be assumed to be unstable, producing a
uniform distribution of pollutants within the box. The ability
to predict "hot spots" or areas of high concentration was thus
eliminated by the use of an airshed model. The Gore Valley was
divided into four airsheds, each defined by a separate develop-
ment area having difference population densities and growth
rates. These airsheds are Bighorn, East Vail, Vail Village and
West Vail. The Upper Eagle Valley was divided into five air-
sheds. The Minturn airshed was located directly over the town
of Minturn. The Dowd-Avon airshed was associated with the
Eagle-Vail planned development. Benchmark and the lower part of
the Beaver Creek development were in the Avon airshed. The
upper and middle portions of the Beaver Creek planned develop-
ment defined the Beaver Creek airshed. The Avon-Edwards airshed
included the Arrowhead planned development.
The box model was developed in order to predict 24 hour (par-
ticulate) "worst case" episodes. It lacked specific mixing
height data which had to be assumed. Worst case is defined as
a period when poor dispersion conditions coincide with peak
emissions. By taking a relatively high day for particulate
emissions, December 20, 1975, and known recorded data on wind
direction and speed for that day, the inversion or mixing
height could be calibrated for the model. Several mixing
heights were tested. Calculations using a mixing height of
92 meters produced a 24 hour average concentration of 226 micro-
grams per cubic meter (u/mj), the same as those recorded on a
relatively high 1975 day. (Peak day emissions may occur in-
dependently of the meteorological conditions used in the model.)
Sources of Pollution, Particulates — Major fuel consumption in
the study area consists of natural gas, liquified petroleum
(LP) gas, and wood. Wood-burning fireplaces are a source of
aesthetic enjoyment as well as heat. Historical consumption
-30-
-------
I
U)
Table 11
Average Airshed Cross-Sectional Parameters
Airshed
Bighorn
East Vail
Vail Village
West Vail
Minturn
Dowd-Avon
Beaver Creek
Avon
Avon-Edwards
SOURCE: Marlatt
Width
Kilometers (miles)
.5
.5
.6
.6
.5
.9
.6
.9
.9
and Gelinas,
(.3)
(.3)
(.4)
(.4)
(.3)
(.6)
(.4)
(.6)
(.6)
1975
Height
Kilometers (miles) Theta 1( ) Theta 2( )
3.0 (1.9) 32.0 22.0
3.7 (2.3) 29.0 25.0
3.7 (2.3) 14.0 18.0
4.3 (2.7) 19.0 22.0
3.5 (2.2) 27.0 12.0
4.0 (2.5) 18.0 26.0
3.6 (2.3) 15.5 18.0
3.3 (2.1) 13.0 17.0
4.0 (2.5) 11.0 14.0
>
\ / Mixing
\ / Height
-7f\ /r^
/ \ /^\
I «-, \ S WTHTH ^ /A ri \
Length along centerline of valley
Average Cross-Sectional Area
-------
UPPER EAGLE VALLEY SANITATION DISTRICT
VAIL WATER AND SANITATION DISTRICT
REDCLIFF WATER AND SANITATION DISTRICT
ENVIRONHCNTlL IMMCI ST«TEy€NT
FOR A 101 FtCILITICS n.»
A«9HED LOCATION MAP
6-— Dowd-Avon
7 - Beover Creek
8-
9 — AvOf>~6dwords
-------
records for fuel consumption were utilized to calculate
individual household use as well as total use by airshed.
Seventy percent of gas and petroleum consumption occurs from
November to April. During this six month period in 1975, an
average natural gas customer used 140-150 thousand cubic feet.
An average liquified petroleum customer used 14-15 hundred
gallons per year in 1975. (The average LP gas consumption
per customer was divided into each airshed total to obtain the
number of LP gas customers.)
Data concerning 1975 fuel consumption by airshed was converted
to heat units and expressed in terms of emission factors. Both
LP and natural gas produce approximately the same amounts of
particulate per equivalent heat unit, 6804 grams per 10 cubic
feet (one gallon LP gas equals 100 cubic feet of natural gas).
Assumptions regarding fuel consumption and emissions by air-
shed are summarized in Appendix C.
Fireplace contributions for particulates were based upon an
EPA study of emission evaluations for fireplaces which were
located in the state of Washington. The emission rate obtained
for total suspended particulates was .02275 grams per second
per fireplace. The emission factor has not been validated for
the study area. Higher hypothetical factors have been utilized
in other studies. The assumptions used in the model for number
of fireplace units by airshed and by year are given in Table 2
in the Appendix.
Mobile source contributions to particulate levels include high-
way and off-highway sources, with highways being the major
source. Emission estimates are based upon the following con-
ditions: number and length of roads; type of roads (freeway,
arterial, local); traffic volume; and, emission factors con-
tained in EPA circular AP-42, 1976. Emission factors per
vehicle mile for suspended particulates equal .54 grams per
vehicle mile. Assumptions utilized in the model for vehicle
counts and vehicle miles travelled are given in Appendix C
Off-highway mobile source emissions come from trains—eight trains
daily pass through Minturn and Avon travelling east or west.
Each 15 minute trip through the study area is estimated to gener-
ate 283 grams per trip. Fuel consumption is estimated at
25 gallons per trip.
One other category which was not included in the analysis but
which may prove to be a significant source of particulate matter
is the dust from paved roadways. A major source of dust,
in addition to urban runoff,in the study area is the application
of sand during snowstorms. A preliminary report on a study
showed dust emissions ranging from two grams per vehicle mile
in commercial areas to 19 grams per vehicle mile in industrial
areas. Although it is an important source, the data is not
easily extrapolated or validated for the study area.
-33-
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Sources of Pollution, Carbon Monoxide — The sources for CO
emissions are the same as those for suspended particulates. Only
one source, vehicular traffic, was projected into the future due
to the following:
- Very little data exists for CO emissions from fire-
places. Use of the Washington fireplace emission
factors appeared questionable.
- The motor vehicle CO emission factors found in EPA
circular AP-42, 1976, required further adjustment
for altitude. The CO data for mobile highway sources
is within an acceptable range of error; however, fire-
place emissions could not be taken into account.
- In view of the above, gross total CO could not be es-
timated, or the relative contribution from each source.
Carbon monoxide emission factors used in the model are given
below. As can be seen in the Table, emission factors are ex-
pected to decrease over time as a result of the vehicle emis-
sions control program. Other assumptions calculated for traf-
fic, speeds and vehicle miles travelled are given in Appendix C.
TABLE 12
Carbon Monoxide Emission Factors for Traffic
Road Type 1975 1980 1985 1990
Freeway 136.01 81.77 28.67 9.99
Arterial 159.20 101.98 38.81 13.72
Local 271.26 192.58 80.46 28.85
Noise
To establish the effects of noise from a particular source, total
noise output should be taken into consideration. in the study
area, no measurements have been made for background or ambient
noise levels. However, the levels of noise for construction sites
in the Gore and Upper Eagle Valleys can be estimated from current
data. Suburban residential and urban residential noise levels at
construction sites have been evaluated in EPA publications. The
impacts section will address sources of noise as a result of the
project.
-34-
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THE BIOLOGICAL
ENVIRONMENT
Terrestrial Vegetation
The flora within and around the study area vary widely with
elevation, insulation, microclimate and topography. Elevations
within the study area range from 2,300 to 3,048 m (7,400 to
10,000 ft). The climate is typical of the central Rocky
Mountains, with wide ranges in precipitation, temperature and
growing season due to topographic relief and surrounding
mountain ranges. The growing season below 2,743 m (9,000 ft)
is from mid-June to early September. Above 2,743 m (9,000 ft),
freezing temperatures are possible during any month of the year.
The numerous vegetation types in the study area are grouped
according to the dominant plant species into the following six
terrestrial communities: aspen, mixed evergreen, spruce-fir,
mountain brush, meadow and riparian. These plant associations
are shown in Figure 8 on the following page. A list of common
and scientific names of species by community may be found in
Appendix D.
Aspen communities occur on moist sites between 2,286 and 3,048 m
(7,500 to 10,000 ft) and are scattered throughout the study
area. Aspen are distinctive because they are the only broad-
leaved tree to form extensive communities on the uplands.
Although aspen groves are dense, sufficient light reaches the
forest floor to permit development of an abundant and diverse
understory. Two major associations of aspen communities occur
in the study area. The first type is found in areas of greater
soil moisture and depth. The understory is luxuriant and con-
tains snowberry and wild rose as the dominant shrubs. Peavine,
vetch, arnica, geranium, tall larkspur, elk sedge and wild rye
dominate the herbaceous stratum. The second type of aspen
community is located on sites with drier, more rocky and shallow
soils. Serviceberry, chokecherry and snowberry dominate the
shrub stratum. Lupine, yarrow, aster and brome grass are some
of the more common herbaceous plants.
The mixed evergreen forest is the prevalent vegetation type
found in the study area. Lodgepole pine dominates the mixed
canopy, with Engelman spruce and subalpine fir representing
other dominant species. Aspen and Douglas-fir are considered
subdominants and occur with less frequency in moist locations
throughout this vegetation type. These dense mixed stands are
distributed throughout the study area at elevations between
2,256 and 3,048 m (7,400 to 10,000 ft). The shrub and herb-
aceous understory of this community is generally very sparse due
to the closed canopy overhead and acidic properties of the
soil caused by the litter of the evergreen communities. Myrtle
-35-
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UPPER EAGLE V»LL£T S4XIT1HON
VAIL WATER AND SANITATION DISTRICT
REDCLIFF WATER AND SANITATION DISTRICT
FON 4 20' **Ci
VEGETATION DISTRIBUTION
MAJOR DRAINAGES
-------
blueberry, mountain-lover, peavine, arnica and aster are the
predominant herbaceous plants, with buffalo-berry, and wild rose
dominating the typically meager shrub stratum.
The spruce-subalpine fir community is the dense, coniferous
forest found between 2,743 and 3,048 m (9,000 and 10,000 ft).
These cool, moist, high mountain forests form the most homo-
genous and continuous vegetation types found in the study area.
The dense canopy is dominated by Engelman spruce and subalpine
fir with aspen and lodgepole pine sometimes occurring in the
subclimax stage. The tightly-packed canopy creates so much
shade that the understory of myrtle blueberry, arnica, vetch
and wintergreen is very sparse. The spruce-subalpine fir com-
munity is the climax coniferous forest type found in the upper
regions of the study area. With control of fires and other
disturbances, the aspen and mixed evergreen communities at these
elevations will gradually be replaced by the spruce and sub-
alpine fir community.
The meadow community occurs from 2,134 to 3,048 m (7,000 to
10,000 ft) within the study area. Its species composition varies
from location to location due primarily to moisture conditions.
Aspen, lodgepole pine or mountain brush communities may surround
the meadow vegetation type. This community is dominated by
grasses and sedges. Fescue, sedges, bluegrass, timothy and
orchard grass are the dominant herbaceous species. Yarrow,
thistle, plaintain, and dandelion are the most common herbs.
Willows are the only shrubs found in this community- Lower mea-
dows in the study area are used extensively for agriculture and
support hay production and livestock grazing. Higher meadows in
the study area are used primarily for livestock grazing and also
provide a large portion of the food supply for some of the large
wildlife.
Dry, southern exposures support the mountain brush community.
It is found predominantly at lower elevations in the study area
between 2,286 and 2,400 m (7,500 to 8,200 ft). Soils of mountain
brush vegetation type are moderately deep, well-drained and rocky.
Species composition of the mountain brush community varies and
depends upon soil parent material and soil moisture. This com-
munity is dominated by serviceberry, mountain mahogany and snow-
berry, with big sagebrush, buffalo-berry and bitterbrush occur-
ring in lesser amounts. The herbaceous stratum is moderately
developed with aster, yarrow, sulfur flower, wheat grasses,
needle-and-thread grass and Indian rice grass as the more domin-
ant species. Continued maintenance of the mountain brush com-
munity depends upon the high solar radiation received on southern
exposures throughout the study area. This high solar radiation
causes rapid evaporation of any available moisture, thus
restricting growth to the mountain brush community which can grow
on areas where reduced soil moisture conditions occur.
-37-
-------
The riparian community occurs in narrow strips alonq the flood-
plains of streams and rivers throughout the study area. The
vegetation is rich and diverse relative to other communities
in the study area. The riparian vegetation types are con-
spicuous to the casual observer because they occupy valley
floors where, due to the more favorable topography, roads are
usually constructed. However, the riparian vegetation actually
constitutes only a minor part of the overall landscape. Groves
of narrowleaf cottonwood trees form narrow, discontinuous bands
along the rivers and streams. Mixed with the cottonwood groves
are aspen, Douglas-fir, blue spruce, Engelman spruce and an
occasional Rocky Mountain juniper. The understory of the ripar-
ian community consists of alder, dogwood, willow and Rocky Moun-
tain maple in the shrub layer. The herbaceous understory is
very diverse and represented by horsetail, monkshood, bluebell,
cow parsnip, sedge, brome, three-awn grass, fescue, and wild rye
as the more dominant species. The riparian community, because
of its floral diversity, is considered a very stable vegetation
type. However, it is dependent upon a constant supply of good
quality water for maintenance.
Terrestrial Wildlife
The distribution of the wildlife in and around the study area is
primarily influenced by vegetation distribution and topography-
As noted in the previous section, vegetation within the study area
can be grouped for the purpose of discussion into six communities.
The wildlife of the area can also be grouped into either species
which are almost entirely associated with one of the six vegetation
types or species which lack definite vegetative associations. A
list of common and scientific names of wildlife expected to occur
in the study area is found in Appendix E.
Wildlife Associated with Vegetation Communities — Most wildlife
species occurring in the study area can be observed in two or
more vegetative communities. However, the wildlife species
discussed here represent the most characteristic species found
in each vegetation type.
The riparian community is associated with the area's surface
waters and is a focal point for numerous species that come for
water. The only species of amphibians located within the
study area are the tiger salamander and the leopard frog, which
frequent ponds and slow-moving streams. Other species associated
with the aquatic portion of this community are the mallard, the
dipper, and the beaver. Birds found in riparian vegetation
include: Baltimore oriole, great blue heron, Say's phoebe, yellow
warbler and the red-winged blackbird. In addition to these
species, most of the bird species inhabiting the mixed evergreen
community may also be observed near water. The western jumping
mouse is the only mammal restricted to the dense riparian
vegetation.
-38-
-------
The meadow community may be found on the broad floodplains in the
lower portions of the study area adjacent to the riparian com-
munity or, to a more limited extent, in the higher elevations
associated with the various forest or brush communities. The
existence of this community depends to a large extent on the
level of the underlying water table. Since the lowland meadows
are closely associated with the riparian community, these two
communities tend to overlap in their animal species composition.
The western garter snake and the gopher snake frequent the low-
land meadow. Both of these species, the only snake species
found in the study area, inhabit the upper meadow community and
adjacent upland communities. The most abundant bird species of
the lowland meadows include the marsh hawk, killdeer, horned
lark, western meadowlark and the savannah sparrow. Predatory
birds such as the red-tailed hawk and the great horned owl fre-
quent the lowland meadows for prey. Several small mammals which
serve as prey for these raptors include Richardson's ground
squirrel, northern pocket gopher, mountain mole and the longtail
mole.
Species composition of the upland meadows is similar to that of
the lowland areas; however, the higher elevations result in a
shortened growing season and severe environmental conditions.
The effect of the shortened growing season is an overall lowering
of productivity and abundance of animals which inhabit this
region.
Because of the similarity of animal species composition in the
aspen, mixed evergreen and the spruce-fir communities, they have
been grouped together as a single habitat type. A large
variety of bird species,including the sharp-shinned hawk, blue
grouse, broad-tailed hummingbird, hairy woodpecker and many
species of songbirds inhabit the mixed woodland community. Mam-
mals found here include the snowshoe hare, Uinta chipmunk,
golden-mantled ground squirrel, and black bear.
Upper reaches of the mixed woodland community, primarily composed
of stands of Engelman spruce and subalpine fir, experience severe
environmental conditions. Dense canopy of the Engelman spruce
effectively cuts the light level at the forest floor. This,
coupled with the short growing season, drastically reduces the
understory which most animal species rely on for food and shelter.
The mountain brush community occurs on dry, south-facing slopes
within the study area. Because of the lack of moisture typical
of southern exposures, few vegetative species are observed in the
area. Similarly, few animal species are full-time inhabitants of
this community- The sagebrush lizard and the eastern fence lizard
commonly inhabit this community-
Wildlife Species Lacking Definite Vegetation Associations -- Some
animalspecies lack specific associations with vegetation types
-39-
-------
but "key" in on a particular aspect of their environment such
as cliffs or brush for nestling, brush for cover, or a particular
food source. Bird species fitting into this category include the
golden eagle, American kestrel, great horned owl, barn swallow,
violet-green swallow, rough-winged swallow, black-billed magpie,
common raven, and mountain bluebird. Mammal species in this
category include the white-tailed jack rabbit, least chipmunk,
deer mouse, coyote, and bobcat.
The white-tailed jack rabbit inhabits open areas (e.g., mixed
brush, meadow, mixed evergreen, and "edge" habitat) throughout
the study area. The least chipmunk and deer mouse are the most
numerous and ubiquitous of the mammalian species occurring within
the study area. These species inhabit all vegetation types,
with local abundance in brushy areas. Both the coyote and bobcat
occur throughout the study area except in the spruce-subalpine
fir forests.
Game Species — Game species,which are the objects of considerable
hunter attention within Eagle County,include mourning dove, blue
grouse, white-tailed rabbit, snowshoe hare, Nuttall's cottontail,
elk, mule deer and black bear.
Mourning dove inhabit mountain brush, forest edge, and other
brushy areas adjacent to water, while blue grouse inhabit mixed
evergreen and subalpine fir vegetation.
Elk inhabit forest areas and higher elevation mountain brush
throughout the study area during the summer. In the winter, elk
move down to the mixed evergreen forest. The areas generally on
south-facing slopes in the northern part of the study area from
Avon to Dowds Junction south of the Eagle River from Dowds Junc-
tion to Red Cliff are either winter range or critical winter
range for elk. In addition to the winter range, calving areas
occur at elevations just above or overlapping with existing winter
range.
The mule deer utilize mountain brush, mixed evergreen, meadow,.
riparian and forest-edge vegetation types of the study area,
avoiding to some extent the fir forests. Most of the study area
is summer range; however, a critical migratory route and winter
range is also found immediately north of Gore Creek. Deer use
this corridor to travel from summer range to winter northwest of
Avon, as shown in Figure 9, on the following page.
Endangered and Threatened Soecies -- The peregrine falcon, listed
on the federal endangered species list, is a potential year-round
resident of this section of the Rocky fountains. Favored
habitat includes cliffs or bluffs for nesting, with adjacent
riparian areas for hunting. Several locations within the study
area provide both of these requirements, but it is presently
unknown whether this species nests in the area.
-40-
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---
1 : -- ~ L-
- * —.. <_' • . - L ^4-»—v%-i
UPPER £**.-£. VALLEY SANITATION O'STBlC1"
VAIL «**EO AND SANITATION
REDCL FC »ATER AND SAN'TAT>ON DISTRICT
-------
Aquatic Biology
Most of the upper Eagle River and its tributaries represent
highly pristine, cold water mountain streams that support a
diverse aquatic community. However, as these waters approach
more populated regions of the study area, the quality of these
streams decrease as does the diversity of aquatic organisms.
The major components of mountainous, cold-water biota include
aquatic plants, aquatic invertebrates, and fish. Each of these
is interrelated to one another and is dependent upon
environmental factors.
Aquatic Vegetation — The major source of plant material to
mountain streams originates from outside sources such as ter-
restrial vegetation. This material enters the food chain
within the streams and may be eventually consumed by several
species of aquatic invertebrates.
Aquatic vegetation of rivers and streams is made up of phyto-
plankton (free-floating microscropic plants), periphyton
(attached microscopic plants), and macrophytes (large attached
plants). Except for two 1974 reports on Beaver Creek, no
specJ fie information is available on any of these forms of plant
life in the Eagle River or its tributaries. In most high
mountain, cold-water streams, annual productivity of these com-
ponents is very low because of the lack of necessary plant
nutrients, the cold waters, and the absence of sufficient amounts
of sunlight.
Of the three forms of aquatic vegetation just mentioned, peri-
phyton normally is the major source of in-stream production within
mountain streams or rivers. Periphyton is responsible for the
"slick" feeling of rocks and other materials in or near mountain
streams.
Macrophytes, or large, attached aquatic plants such as pond lilies
or cattails, usually contribute little to the productivity of
mountain streams. Only two areas within the entire study area
were noted to have any macrophyte production, one being below the
old holding ponds of the New Jersey Zinc Corporation and the other
below their new holding ponds. It is possible that these stands of
cattails are a result of a rise in the groundwater level associated
with the holding ponds.
Phytoplankton production is mountain streams is extremely low.
The main source of phytoplankton to streams is usually overflow
from lakes or ponds which maintain a standing crop of phytoolankton
or from dislodged periphyton.
-42-
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Aquatic Macro-invertebrates -- The composition of the aquatic
macro-invertebrate fauna of a high mountain stream include a
variety of species with representatives from almost all inver-
tebrate phyla. Insects usually compose the major portion of
the aquatic macro-invertebrate life in such streams. A number
of insect orders have been identified from the waters of the
study area, including mayflies, beetles, flies, mosquitoes
and midges. Some of these contain species which occur only
for a portion of their life cycle in the aquatic community,
while others are entirely terrestrial. The order Hymenoptera
(ants, wasps, bees, and sawflies), for example, is entirely
terrestrial yet composes a large portion of the food supply of
fish of the area.
Until recently, the most complete analysis of the aquatic
macro-invertebrates of the Eagle River and its tributaries
was conducted in October 1966 by the Federal Water Pollution
Control Administration and published in their report of 1968.
This report provides the best baseline information for the
study area since the study was conducted before large-scale
development of Gore Creek.
This report indicates the biological condition of the Eagle
River up-stream from, adjacent to, and downstream from the influ-
ence of the industrial wastes of New Jersey Zinc Corporation in
the mid-1960's. Generally, these data indicate that the con-
dition of the Eagle River, at that time, was very good above
Gilman. Near Gilman, water quality degenerated and was
uninhabitable near the point where the effluent from the old
New Jersey Zinc Corporation tailings ponds was discharged.
The river did not significantly recover until a point near Dowds
Junction. A copy of FWPCA data concerning the Eagle River is
found in Appendix F.
A recent survey of the Upper Eagle River and Gore Creek by the
Colorado Department of Health indicates similar conditions. The
Eagle River above Gilman is an excellent fishery with a good
macro-invertebrate population. Despite efforts by the New Jersey
Zinc Corporation to control non-point source seepage from their
tailings ponds, high levels of certain metals are still
occasionally encountered within the Eagle River. The present
macro-invertebrate fauna of the Eagle River between Gilman and
Dowds Junction is still lower than its upper reaches, but some
re-establishment has taken place. This probably has resulted
from improved discharge quality from New Jersey Zinc Corporation
tailings ponds. Spills of untreated mine tailings into the
Eagle River occasionally create localized fish kills, but because
they move through the area so rapidly, are thought to affect the
benthic macro-invertebrate populations very little.
Limited macro-invertebrate data on Gore Creek during the 1966
sampling by FWPCA make analysis difficult. One station located
approximately one mile upstream from Vail showed low species
-43-
-------
diversity (eight species) and relatively low numbers of organ-
isms (75 individuals) per square foot compared to the second
Gore Creek station located one mile above the confluence with
the Eagle River (17 species and 285 organisms per square foot).
Based on the few samples taken by FWPCA, these data indicate
that, as early as 1966, the town of Vail had influenced the
aquatic macro-invertebrate constituency of Gore Creek, providing
a more diverse population with greater biomass.
A survey of the aquatic insects in Gore and Black Gore Creeks
was conducted in August 1971 in relation to the completion of
1-70 over Vail Pass. It presents summer data, whereas the
FWPCA provides only winter data. Results of bottom sampling and
fish stomach content analysis indicate that, although mayflies
represented by far the largest portion of the aquatic insects in
Gore and Black Gore Creeks, they represented only 21 percent of
the food items found in the stomachs of brook trout. Terres-
trial insects provide over half of the food items found in brook
trout stomachs. Although it is impossible to estimate the
actual food biomass contribution by each species, the data in-
dicated that the terrestrial species provide a much higher food
contribution to brook trout than do the aquatic insects. This
factor reflects the general lack of plant life available to
aquatic insects in high-mountain streams.
The Colorado Department of Health study previously mentioned
suggests, as does the FWPCA report, that the town of Vail may
influence the aquatic biota of Gore Creek. Data from this study
show that below the point of discharge of the Vail wastewater
treatment plant there is a decrease of species diversity and an
increase in the population of aquatic macro-invertebrates.
Although the statistical validity of analysis of a single sample
is questionable, the apparent discrepancy between these two
studies may in fact indicate an alteration of Gore Creek's aquatic
biota within the past decade.
Fish — Although several cursory inventories have been made on the
fisheries of the Upper Eagle River Valley, no annual or seasonal
productivity estimate has been made. The Colorado Division of
Wildlife has published a list of fish species known to occur within
Eagle County: these are included in Appendix G. in addition to
approximate species composition, an overall evaluation of several
of the study area's streams was included in a statewide stream
evaluation conducted by the Division of Wildlife in 1972. Results
of this study are summarized in Table 13, on the following page.
The Major Drainages Map, Figure 10, following Table 13, illustrates
the location of the major tributaries. Although the rating system
used in this evaluation is, for the most part, subjective, it acts
as a general guide to indicate an overall evaluation of the area's
fishery.
-44-
-------
TABLE 13
COLORADO DIVISION OF WILDLIFE EVALUATION OF SELECTED
UPPER
Creek
Homestake
Fall
Two Elk
Cross
Black Gore
Booth
Red Sandstone
Ruffehr
Beaver
Gore
Turkey
E. Fork Eagle
ater Quality
3
8
10
6
10
6
9
6
9
10
2
6
7
o
•H
CO
PS
cu
,—1
14-4
•H
OH
r-l
O
O
9
4
5
9
6
5
7
5
5
9
5
8
EAGLE RIVER
BASIN
TRIBUTARIES.
1972 Stream Evaluation Criteria
c
r! 4J o
^ en o -H
r-l iH -H 4J
O. fa en )-i -H
O. en 4J -o
3 «-i tn cu en c
cu en o en o 1-1 o
M CU < O C_>
3 TJ C 0
4-1 O O O rH M i-l
CO >, O i-l -, co
CUiH-HO CU .C (1) .C CU
H
9
A
5
4
5
5
5
6
6
8
6
8
o
9
10
5
10
6
9
6
9
10
3
5
8
fa
9
4
5
5
3
-
5
6
4
9
6
8
9
2
-
10
4
-
5
10
9
8
9
10
J
8
10
10
10
10
10
10
10
1
8
10
10
Pi
9
1
2
2
8
2
4
2
1
7
10
5
z
9
6
7
10
9
7
7
9
4
9
6
-
Pu
4
8
6
10
6
10
5
9
7
2
5
4
10
1
4
3
3
5
3
4
5
8
5
6
c
0
•H
4-1
•H
4J
CU
D.
O
O
en
•H
fa
00
3
0
PS
10
10
10
10
10
10
10
10
10
10
10
10
r-t
CO
4-1
o
H
103
70
65
93
76
72
73
89
63
83
83
84
Approximate /',
Species
Composition
4-1
3 4-1
4J 4J O 3
33 V- 0
O 0 H M
1- M H
H H 3
O Hi
C ^! & >
3 O C -H
O O -H 4J
M J-i CO CO
pa co PS z
70 9 20 1
40 60
70 30
33 33 33
100
60 10 15 15
100
90 5 5
SOURCE: Based on 1972 evaluation conducted by the Division of Wildlife. Rating
on each criteria is from 1 (low or poor) to 10 (high or excellent).
Total possible score is 120.
-45-
-------
'-'- •/.•••
. - v far, :,
xw-
UPPER EAGLE VALLEY SAN'TATION DISTRICT
VAIL WATER AND SANITATION DISTRICT
REDCLlfF WATER AND SANriTION DISTRICT
-------
The Division of Wildlife is presently conducting a more detailed
evaluation which will eventually provide more objective values.
A discussion of the major fisheries of the study area, based on
Colorado Division of Wildlife information and other pertinent
data, is presented in the following paragraphs.
The upper reaches of the Eagle River south of the study area are
characterized by high water quality- The favorable pool-to-riffle
ratio and temperature provide good habitat for the fish popu-
lation, which consists of 90 percent brown, five percent native
cutthroat, and five percent brook trout. Successful natural
reproduction makes stocking unnecessary.
The data indicate that the water and fishery qualities of Home-
stake Creek, a major tributary to the headwaters of the Eagle,
are excellent. Of all the streams in the area, it receives the
highest rating in the evaluation. Its diverse fishery species
composition is: 70 percent brown, 20 percent rainbow, nine per-
cent brook, and one percent native cutthroat. Although success-
ful natural reproduction is reported, it is regularly stocked.
Black Gore Creek is characterized by good water quality and
abundant natural fish reproduction. The stream receives some of
the rainbows that are stocked into the Black Lakes on Vail Pass,
a very popular fishing and camping ground, but is not stocked.
The fish population above Vail in Gore Creek consists of 60 per-
cent brown, 10 percent brook, 15 percent rainbow, and 15 percent
native cutthroat, occasionally supplemented by hatchery-reared
rainbows. The fish population below Vail consists predominantly
of brown trout which migrate out of the Eagle River to spawn.
Gore Creek has undergone several physical changes in channel design
as a result of highway construction and development within the
floodplain. Such activities have caused temporary water quality
problems and destruction of aquatic wildlife habitat. The estab-
lishment of aquatic biota in new stream channels progresses
rather rapidly; for short sections of streams, less than a year.
Rechannelization of the lower portions of Gore Creek has caused a
constriction of the stream which has proved to be beneficial to
the fishery during periods of low flow. If extensive development
of the floodplain in the vicinity of Vail has caused barriers to
fish migration, it has not been documented.
The water quality of Beaver Creek is excellent, and trout repro-
duction is abundant. Five fish species were collected by electro-
fishing during the summer of 1972, including brown, rainbow,
native cutthroat, and brook trout and Piute sculpin.
-47-
-------
THE PHYSICAL
ENVIRONMENT
The physiographic characteristics of the area, including topog-
raphy, geology and soils, govern the suitability of the land for
wastewater treatment plant site location, pipeline routing, and
the application of effluent or sludge. The descriptions presented
herein are accompanied by detailed appendices which address the
engineering considerations inherent in the maps portraying the
topography and the location of various rocks and soil formations.
Geology and Soils
The boundaries of the Upper Eagle Valley, Vail and Red Cliff
Sanitation Districts encompass private lands along Gore Creek and
the Eagle River. The study area is surrounded by National Forest
lands, except for the western boundary where the Eagle River
Valley widens out to privately-owned irrigated farmlands and
ranchlands.
The geologic location of the study area is the Southern Rocky
Mountain Physiographic Province between the northern end of the
Sawatch Mountain Range and the western flank of the Gore Range,
as shown in Figure 11,on the following page. The altitudes have
been discussed under Terrestrial Vegetation.
Snow Avalanche Hazard — As a result of the elevation, topography
and climate of the area, varying degrees of avalanche hazard
exist. Numerous active avalanche tracks may be seen on north-
facing slopes within the study area. Figure 12, on the second
following page, depicts the varying degrees of avalanche risk for
the area.
Bedrock Geology — The rock units in the study area are of
sedimentary origin, with the exception of three small areas of
Precambrian granitic rocks, consisting of only a few acres each,
on the southern and eastern edges of the area. Figure 13,
following Figure 12, shows the location and extent of each
bedrock unit in the study area. In Appendix H, each bedrock
unit is described as to physical characteristics (weathering
characteristics, erodibility, engineering characteristics, and
potential or actual resources). These characteristics apply to
depths 24 to 60 inches beneath the ground surface. The section
on Soils and .-urficial Deposits will address characteristics
of the first 40 to 60 inches of ground surface.
Geologic Hazards and Engineering Geology — The map of Geo-
logic Hazards and Engineering Geology, Figure 14, following
Figure 13, should be interpreted together with Appendix I,
which describes suggested planning and precautionary measures
-48-
-------
TIU
HATIC
rot
1 AlAfAMC
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NATIONAL i' •
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t
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BCklDE
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KER3=»* i-^^K^SaiiiEjJr'lS
UPPER EAGLE VALLEY SANITATION DISTRICT
VAIL WATER AND SANITATION DISTRICT
REDCLIFF WATER AND SANITATION DISTRICT
ENVIRONMENTAL IMPACT STATEMENT
FOR A 201 FACILITIES PLAN
S ^L^" .7
PHYSIOGRAPHIC PROVINCES
-------
M:.m^ 'fo
UPPER EAGLE VALLEY SANITATION DISTRICT
VAIL WATER AND SANITATION OISTRICT
REDCLIFF WATER AND SANITATION DISTRICT
CNVmOKHENTAL IMMCT STATEMENT
FOII « 201 FACILITIES »l»N
V ''
I ' f
-------
1 - . -
• • / •/
';/ ; ,.
f "-" - •- 'if/" ' .. ~'?
\ - .' ^/' j, * .'jftjf * _.-i
•3J^' v:-f
UPPER EAGLE VALLEY SANITATION DISTRICT
VAIL WATER AND SANITATION DISTRICT
REOCLIFF WATER AND SANITATION DISTRICT
ENVIRONMENTAL IMPACT STATEMENT
FOR A 2OI FACILITIES PLAN
MAP OF BEDROCK GEOLOGY AND
KNOWN OR POTENTIAL MINERAL RESOLPCES
-------
^3>HP
" «TItt'> i&trT"
JPPER EAGLE VALLEY SANITATION DISTRICT
VAIL WATER AND SANITATION DISTRICT
REDCLIFF WATER AND SANITATION DISTRICT
GEOLOGC HAZARD 8 ENONEEFBNG GEOLOGt MAP
-------
that should be taken before development of various types of lands
within the study area. Considerations used in compilation of
the map included the bedrock type, soil type, slope, vegetation,
snow avalanche hazard, and geologic hazards within each area.
(This map was used as a planning guide, and should not be sub-
stituted for on-site tests prior to construction.)
Seismicity -- Although the seismicity of the region is not
well-known, five major faults have been identified in the area.
A two-year study is presently under way by the Colorado Geological
Survey to evaluate the seismicity of Colorado. From preliminary
information, the area west of longitude 104 degrees (along the
eastern line of the Front Range), can expect earthquakes of a
maximum Richter intensity of between 4 and 5. Richter intensity
2.5 is defined as a barely-felt earthquake. Richter intensity
5 may cause slight damage in well-constructed buildings or moder-
ate damage to poorly-constructed ones.
Mineral Resources — Between Red Cliff and the Dowds Junction
area lies the Battle Mountain or Red Cliff mining district.
Initial discoveries of gold and silver took place in 1879 in a
mineralized portion of the Leadville Limestone. Copper and zinc
content of the ore increased with depth, and throughout the
1930's, the mining district produced approximately 85 percent of
the copper and 65 percent of the silver output of Colorado.
Today the Oilman zinc mine, two miles north of Red Cliff, is
operated by the New Jersey Zinc Corporation.
Other minerals of potential economic significance within the study
area are confined to glacial and fluvial gravel deposits,
potential evaporite deposits in the Eagle Valley Evaporite
sequence, and potential building block, aggregate, riprap and
agricultural lime in the pre-Pennsylvanian sequence in the south-
west portion of the study area. Five gravel pits exist in the
area, two at the junction of Cross Creek and the Eagle River, and
three near Avon. The Minturn formation was prospected for
uranium but no deposits of economic value were located.
Soils and Surficial Deposits — This section presents the engin-
eering geology and geologic hazards of the first 40 to 60 inches
of ground surface. It is this area which is critical in con-
sidering revegetation, erosion hazard, water-holding capacity,
runoff, plant nutrient levels and potential irrigable areas.
Soils classifications and surficial deposits appear in Figure 15,
on the following'page. A complete"description of each soil
category, its geomorphic structure and type, appears in Appen-
dix J which also includes an evaluation of the suitability of each
for septic systems, landfill, topsoil, foundations, roadfill and
irrigation.
-53-
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UPPER EAGLE VALLEY SANITATION DISTRICT
VAIL WATER AND SANITATION DISTRICT
REOCLIFF WATER AND SANITATION DISTRICT
ENVIRONMENTAL IMPACT STATEMENT
FOR A 101 FACILITIES PLAN
MAP Of SOLS ft SURf ICIAL DEPOSITS
-------
The soils in the area are stony, gravelly loams and clay loams.
The pH is generally well within limits for normal plant growth.
Slopes are generally greater than 20 percent, except on
alluvial fans, terraces and stream bottoms where slopes vary
from 6 percent to 20 percent. Permeability is usually moderate
to rapid, runoff is moderately low, and the potential for frost
action or shrink/swell is low to moderate.
Soils are generally neutral to slightly acid on the wetter,
northern exposures, where heavier vegetation and a greater
amount of organic acids cause more soluble chemicals to leach
from the upper soil horizons. On drier, southern exposures,
soils tend to be neutral or slightly alkaline. Chief obstacles
to excavation and construction of waste disposal sites will be
excessive stoniness and moderate to rapid permeability. In-
hibiting factors for revegetation will be steep slopes and rapid
erodibility once the natural root mat is removed.
In the western portion of the study area, from one mile west of Dowds
Junction to the Arrowhead area, alkaline soils are common on the
hills above the stream terraces. These soils have formed over
evaporites which release potassium, sodium and calcium ions
into the soil, increasing alkalinity and salinity. They
approach the upper limits of alkalinity for normal plant growth,
and will be more difficult, in terms of revegetation, to
reestablish natural plant communities.
Field investigations indicate little to no irrigated land within
the boundaries of the study area. River terraces in the south and
• east are too steep and narrow. Potentially irrigable land
exists in the western portion of the area, along terraces of the
Eagle River. This land was irrigated in the past, but it has now
been subdivided and is not cultivated.
-55-
-------
Hydrology and Water Quality
The surface waters in the vicinity of the study area consist of
high-mountain, cold water streams, scattered beaver ponds and
small lakes. Major drainages were shown in Figure 10. The Eagle
River and its tributaries contribute the major portion of the
surface water volume. High flow periods in these streams occur
during the spring snowmelt (May and June), while low flows occur
most frequently during the winter period of December through
February and the late summer months of August and September.
Elevations of the streams range from 2,743 m (9,000 feet) on the
upper extremities of Gore Creek and the Eagle River to less than
2,286 m (7,500 feet) on the Eagle River near Avon. Annual pre-
cipitation varies from 45.7 cm (18 inches) near Avon to over
114.3 cm (45 inches) at higher altitudes. Two-thirds to three-
fourths of this occurs as snowfall.
Stream Identification and Water Supply — There are 32 major
tributaries to the Eagle River in the study area. U. S. Geologi-
cal Survey monitoring stations are located on sixteen of these.
Appendix K contains average and extreme discharges for each
station for the period of record.
Precise hydrological data are not available for the Eagle River
near Avon. Available data indicate that the Eagle River below
Gypsum drains a watershed of 2.445 km (944 square miles) with
a mean annual discharge of 508 x 106 m (412,200 acre feet) per
year.
Periods of low flow are associated with seasonal extremes in
water temperatures. The lowest annual water temperatures occur
during the winter low flow period, while the highest typically
occur during the summer low flow. Decreased dilution capability
in the streams during these periods often results in maximum
concentrations of dissolved chemicals. For this reason, cal-
culations of the allowable discharge of various types of man-
produced pollutants in order to meet stream water quality stan-
dards, are based upon low flow levels. The three techniques for
calculating critical low flows used most often in Colorado are
Average Low Flow, 7-day/10-year Low Flow and The Sag Chain
Determinations of Low Flow. For the purposes of this report,
the 7-day/10-year Low Flow method has been utilized since it
conforms to the 303(e) study approach and the methodology
adopted for other water quality planning efforts.
With adoption of PL 92-500 in 1972, and the subsequent National
Pollution Discharge Elimination System, it became essential to
establish low flow data (for discussion see the following
section). EPA attempted to solve the problem by developing the
7-day/10-year low flow criteria. The 7-day/10-year low flow
represents a calculated low flow determined by averaging the
-56-
-------
lowest flows of a stream recorded for a period of seven consecu-
tive days which would occur within any ten consecutive year period.
Many federal and state agencies are now considering adoption of
this method to determine maximum allowable discharge of pollu-
tants into surface waters. Table 14, on the following page, lists
the 7-day/10-year low flows determined for several of the creeks of
the study area.
Flood Hazard — The opposite extreme of low flow is high water
which accompanies spring runoff. In excess of 80 percent of the
total annual discharge of several sub-basins of the Eagle River
drainage occur during this time. The physical forces accompany-
ing these high flow periods bring about high suspended sediment
loads and debris which may be detrimental to aquatic life and
often cause habitat destruction. However, these periods are
also a time of dilution and flushing of toxic substances from the
streams as well as a time of increased food supply washed in
from surrounding terrestrial environment. Extremes in high
water level also can cause physical destruction of human habitat.
Figure 10 illustrated the 100-year flood plain for the Eagle River
and Gore Creek compiled from two previously conducted studies,
one by the U. S. Geological Survey (USGS) and the other by
Hydro-Triand, Ltd. for the Colorado Water Conservation Board in
1975. Human habitation in the Eagle River and Gore Creek
valleys remains predominantly in or near the flood plain. The
flood plain has been modified by constructing roads and buildings,
thereby increasing the flooding potential during periods of high
flow.
The Hydro-Triad report showed that: 1) although many areas in
Vail may become flooded and experience water damage and sediment
deposition, probably little significant structural damage would
result directly from the 100-year flood, 2) significant
structural damage may result indirectly from the flood if large
amounts of debris or boulders were moved,3) the 100-year flood
represents a serious hazard to humans who might be caught in the
flood waters. Public Law 92-500, and the instructions issued by
the Army Corps of Engineers in implementing Public Law 93-234,
require special consideration in design where wastewater treat-
ment facilities are located in the 100-year flood plain.
Aquifer Groundwater — The groundwater aquifers of this region
are not well mapped due to the irregular stratigraphy- Due to
normally low yields of deep groundwater wells in this area, they
are seldom used as domestic or agricultural supplies.
Deep aquifer groundwater in this area usually contains few dis-
solved solids but may occasionally contain high concentrations
of trace elements which reduces its potability-
-57-
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TABLE 1 !>
MONTHLY 7-DAY/10-YEAR LOW FLOW LEVELS (in cfs) FOR VARIOUS SUB-BASINS OF THE EAGLE RIVER
Watershed Jan. Feb^ Mar. April May June July Aug. Sept. Oct. Nov. Dt.-.
Gore Creek 13.5 12.7 13.9 19.0 42.5 115.0 31.0 18.7 13.9 12.1 15.5 13.4
Eagle River above
Gore Creek 35.0 33.0 36.0 49.1 109.8 296.0 80.2 48.3 36.1 31.3 40.3 34.6
Eagle River from
above Gore Creek
to below Beaver
Creek (excluding
Gore Creek) 6.1 5.8 6.0 7.6 16.1 44.0 12.4 8.0 6.2 5.4 7.0 6.1
Eagle River from
below Beaver Creek
J, to below Squaw
f Creek 16.1 15.2 14.8 17,1 32.7 89.0 26.2 19.0 15.3 14.0 18.2 16.0
Eagle River from
below Squaw
Creek to above
Brush Creek 19.1 18.0 16.5 17.1 29.1 81.0 25.0 20.8 17.2 16.4 21.5 19.0
Eagle River from
above Brush Creek
to below Brush
Creek 31.4 29.8 25.9 23.8 34.2 101.0 33.1 31.5 27.1 26.5 35.2 31.1
Eagle River from
below Brush Creek
to below Gypsum
Creek 28.9 27.5 22.8 18.5 20.5 65.0 24.1 27.0 24.2 24.2 32.3 28.7
TOTAL - Eagle River
below Brush Creek 150.0 142.0 136.0 152.0 285.0 790.0 232.0 173.0 140.0 130.0 170.0 149.0
SOURCE : Nelson, Haley, Patterson and Quirk, Engineering Consultants 1975
-------
Although groundwater does not contribute significant amounts to
domestic water supplies through wells, an indirect contribution
may exist through groundwater issuing from springs and seeps to
surface water supplies. This may sustain the flow of streams
during periods of low flow, providing for the maintenance of
both aquatic and terrestrial flora and fauna at critical times
of the year. In fact, groundwater contributes approximately
one-third of the total Eagle River annual discharge in the
vicinity of Gypsum.
Alluvial Groundwater -- Alluvial groundwater is derived from the
alluvial or valley-fill deposits, associated with streams. The
permeability of these deposits provides excellent storage capacity
for water during high flow periods, which is released during low
flow periods to adjacent streams. A number of successful wells
yielding up to 570 liters per minute (150 gpm) have been drilled
in the Upper Eagle River valley alluvium. The extent of this
aquifer is presently unknown and the irregularity of its shape
has been demonstrated by unsuccessful drillings near the valley
edge. Because of this, alluvial groundwater is considered as
surface water rather than groundwater under Colorado water law,
controlled by surface water rights administration. Because the
valleys are narrow, large withdrawals of water from alluvial
wells in the area affect stream flow within a short period of
time, and major diversions of stream water quickly affect the
water level of the alluvium. The permeable material making up
these valley-fill deposits control the water flow between these
two sources, and also contributes significantly to the normally
high dissolved chemical content of alluvial water.
Alluvial groundwater may contain high levels of calcium and
magnesium bicarbonates and sulfates and other dissolved salts,
especially in areas of heavy irrigation. A large portion of the
alluvial deposits in the lower portions of the study area are
underlain by basalt, a highly erodible material which may con-
tribute additional amounts of dissolved solids to alluvial
groundwater in the area.
Surface Water — In Colorado, the quality of surface water is
controlled by the Water Quality Control Commission of the Colorado
Department of Health. State surface waters are classified
according to water quality criteria and waste discharges are con-
trolled by a discharge permit system. Programs and regulations
regarding surface water quality standards and pollutant dis-
charges are discussed in detail below.
The upper reaches of the Eagle River and its tributaries have
been classified as BI by the Colorado Department of Health, and
are described as "waters suitable or to become suitable for all
purposes for which raw waters are customarily used, except
primary contact recreation such as swimming and water skiing".
-59-
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However, near the more populated reaches of the study area, the
streams acquire concentrations of some undesirable material.
Certain chemical compounds and water quality parameters warrant
particular attention. These include: 1) Ammonia and other
forms of nitrogen, 2) dissolved oxygen, 3) temperature and pH,
4) pesticides, 5) heavy metals and 6) chlorine residual.
Ammonia — Raw domestic sewage normally contains from 20 to
40 mg/1 of nitrogen, of which about 75 percent is in the form of
ammonia, nearly all of which exists as ammonium ion (NH4+). Most
secondary treatment facilities remove approximately 25 percent of
the total ammonia, leaving 12 to 30 mg/1 of ionized ammonia
in the effluent. Under aerobic conditions (that is, where air is
present), certain nitrogenous bacteria eventually oxidize
ammonia to nitrite (NO2-) and nitrate (NO3-) . This is a natural
process called nitrification which takes place in streams, lakes
and rivers which receive loads of dissolved ammonia.
Un-ionized ammonia (Nt^), as opposed to ammonium ion (NH4+), has
been identified as being highly toxic to aquatic biota. The
ratio of un-ionized ammonia to total ammonia is highly dependent
upon temperature and pH. At temperatures and pH values normally
encountered in sewage and receiving streams, usually less than
ten percent of the total ammonia is in the un-ionized form.
During the winter when stream temperatures are near freezing, this
ratio may decrease to less than one percent.
The mechanism of ammonia toxicity is not clearly understood.
Originally, it was thought that high levels of ammonia prevented
exchange of metabolic gases at the gill surface of fish.
However, recent studies suggest that high concentrations of
ammonia, especially un-ionized ammonia, interfere with the excre-
tion of naturally produced ammonia from fish. The accumulation
of ammonia within fish causes physiological problems which
initially affect the central nervous system. Chronic exposure
to sublethal concentrations appears to cause detrimental changes
in the cells on fish gill surfaces which, in turn, cause
additional stress making the fish less resistant to infection
by other pathological conditions. The pH of water, as noted
earlier, is important in the control of the proportion of the
toxic un-ionized form of ammonia present. However, if high levels
of dissolved carbon dioxide or bicarbonate are found within the
system, the actual pH at the gill surface of fish often remains
sufficiently high to prohibit the uptake of the un-ionized ammonia.
High concentrations of total dissolved solids also cause a de-
crease in the toxic effects of un-ionized ammonia in some instances.
On the other hand, low levels of dissolved oxygen increase its
toxic effects.
Natural levels of ammonia in Black Gore, Bighorn, Mill and
Redstone Creeks, and other relatively undisturbed streams, are
either very low or below the limit of detection. However,
-60-
-------
concentrations increase significantly in water courses near
populated areas. The primary sources of surface water ammonia
in the study area, as identified by the Colorado Department of
Health, are the Vail, Avon, and Red Cliff sewage treatment facili-
ties, and outflow from the tailings ponds of the New Jersey Zinc
Corporation located near the town of Oilman.
Relatively high un-ionized ammonia levels have occurred in Gore
Creek downstream from Vail, and in Cross Creek and the Eagle
River in the vicinity of the New Jersey Zinc Corporation tail-
ings ponds, and in the Eagle River downstream of the Avon Sewage
Treatment Plant. Peak values as high as .07 mg/1 in Gore Creek,
.142 mg/1 in Cross Creek, and .02 mg/1 in the Eagle River have
been recorded, and in both Gore Creek and Cross Creek, average
levels above .02 mg/1 have been documented.
Considerable research has been performed to investigate the
toxicity of ammonia (un-ionized) to various species of fresh
water fish. The following is a brief summary of this research.
- As shown in Table 15 on the following page, a relatively
wide range of LC5Q (concentration at which 50 percent are
killed over a given time period) values have been observed
by various investigators for certain species of trout.
The most consistent 96 hours LC5Q value seems to lie be-
tween 0.2 and 0.4 mg/1, but most authors agree that the
actual value is highly dependent on other factors, and
can only be accurately determined for a particular
stream with an in-situ investigation.
- It has been shown by Ball that over short periods
(36 hours or less), rough fish are less susceptible to
ammonia toxicity than trout, but for extended periods,
virtually all fish are equally affected. Furthermore,
it has been shown that fish are more sensitive to
ammonia than most other aquatic organisms.
- Most investigators point out that many other factors
influence the toxicity of ammonia, including pH,
temperature, alkalinity, carbon dioxide, sodium ions,
and the presence of other toxins. Some of these con-
stituents affect the portion of the total ammonia con-
tent which is in the un-ionized form, while others
react with the ammonia to form more or less toxic
compounds. An acceptable value for total ammonia should
be derived through in-situ bio-assays, before an LC^Q
value for un-ionized ammonia can be determined.
- In determining allowable concentrations for un-ionized
ammonia, the emphasis has been to establish a relation
between the maximum level which can be tolerated by
fish in the most sensitive portion of their life cycle
-61-
-------
TABLE 15
SUMMARY OF RESEARCH ON AMMONIA TQXICITY
Organism
Rainbow trout
Rainbow trout
Rainbow trout
Rainbow trout
Rainbow trout
Rainbow trout
Rainbow trout
Rainbow trout
Rainbow trout
Suckers, Trout
Brook trout
Toxicity mg/1 as N
Un-ionized Ammonia
0.4 96 hr. LC
50
"50
1.5 LC5Q
0.4 24 hr. LC
0.5 96 hr.
0.4-0.58 24 hr. LC
0.39 24 hr. LC
50
'50
0.18 48 hr. LC
15
0.09 48 hr. LCr
0.55 44 hr. LCr
4.0 96 hr. LC
100
2.5 24 hr. LC
100
Source
Lloyd and Herbert (1960)
Merkens and Downing (1957)
Ball (1967)
Herbert and Shurben (1963)
Herbert and Shurben (1965)
Lloyd and Orr (1969)
Ball (1967)
Ball (1967)
Ball (1967)
McKee & Wolf (1963)
McKee & Wolf (1963)
-62-
-------
and the specified LC50 value determined for the waters
in which the fish live. The ratio between the toler-
able and toxic limits is termed the "application factor,"
and recommended values for this application factor vary
over a wide range. They include 0.1 x 48 hr. LC ,
0.12 x 96 hr. LC^o, and 0.05 x 96 hr. LCso- Therefore,
because of the differences in opinion on LC5g values
and application factors, the recommended tolerable
limit could vary substantially. Some researchers
recommend 0.02 mg/1 (as Nitrogen) as a maximum limit.
One recommendation, as stated in an EPA publication, entitled
Ammonia Toxicity, is quoted below:
"Once a 96-hour LC5Q has been determined using the
receiving water in question and the most sensitive
species, in the most sensitive portion of its life
cycle in the locality as the test organisms, a
concentration of un-ionized ammonia safe to aquatic
life in that water can be estimated by multiplying
the 96-hour LCcQ by a determined application factor;
but, in general, the maximum permissible in-stream
concentration of un-ionized ammonia should be 0.02
mg/1 NH3-N f°r waters classified for fisheries use."
The Colorado Water Quality Control Commission is currently
developing new water quality requirements for all state waters.
The currently proposed standards recommend an un-ionized ammonia
restriction of 0.02 mg/1 for all streams which are intended to
support aquatic life.
Other Forms of Nitrogen -- The remaining portion of the nitrogen
content in raw sewage is largely organic nitrogen, most of which
is hydrolized to ammonia prior to and during sewage treatment.
Ammonia can be oxidized to nitrate and nitrite by bacterial
action. This nitrification process takes place in well-oxygenated
bodies of water when ammonia and nitrifying bacteria are present.
Such aerobic bacterial conversion requires four units of oxygen
for each unit of ammonia which is converted to nitrate.
However, this nitrification process occurs very slowly in cold
mountain streams and the oxygen used in this biological conversion
is continuously balanced by the natural aeration processes which
take place within the stream.
Additional pollution problems resulting from this process are
related to the fact that nitrates, and nitrites to a lesser ex-
tent, are necessary plant nutrients. An increase in the amount of
these nutrients can, under certain circumstances, cause an
increase in the growth of aquatic plants. Increased plant pro-
duction may be desirable in relatively unproductive mountain
streams, but excessive production can result in eutrophication,
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particularly in lakes. At extremely high concentrations, nitrates
and nitrites can become toxic to plants and animals, but these
levels are seldom reached solely as a result of sewage.
The Colorado Department of Health has studied the dissolved
oxygen (DO) content of the Eagle River and several of its tribu-
taries. Their report stated an intent to maintain the normally
high level of DO typical of the area and added the DO content
should be one of the most important parameters to be used in es-
tablishing the required levels of wastewater treatment. Analysis
of available data indicated that "dissolved oxygen is not a
problem in the basin at this time based on the standard of 6 mg/1
...." Waters of the Eaale River and its tributaries are usually near
100 percent oxygen saturation—a state which varies primarily
with water temperature but also with chemical content of the
water. The steep gradient and rocky substrate provide excellent
aeration of surface waters and help maintain the high levels of
dissolved oxygen. The oxygen demand resulting from the oxidation
of organic material or conversion of chemical compounds seldom
exceeds the re-aeration rate in these cold, turbulent, mountain
streams. Extremely heavy waste loading from treatment facilities
would be needed to cause a significant decrease in the oxygen
content.
Temperature and pH — In addition to direct effects upon the
metabolism of aquatic organisms, temperature and pH are extremely
important in controlling the effects of dissolved chemicals on the
biota. Temperature and pH may control form, concentration, or
general toxicity of certain heavy metals, pesticides, or other
chemicals, and may affect the growth of undesirable bacterial
contaminants and aquatic plants.
The pH of the streams in the study area occasionally exceed the
9.0 upper limit recommendation for streams of B^ classification.
This elevated level is thought to be a natural phenomenon in many
Colorado streams. Groundwater and alluvial water deposits serve
as the major source of water to the Eagle River and its tributar-
ies during periods of low flow. These waters are characteristically
hard and have a high pH. Stream conditions resulting from such
groundwater inflow appear to have no detrimental effect on
aquatic life.
Due to the adequate mixing of the study area's streams with the
ambient air, temperature extremes have not been a problem in the
past and should not be a problem in the future.
Pesticides — To date, no pesticide pollution problems have been
identified in the Eagle River drainage area. Due to the very
short growing season (80 days), there is little use of agricul-
tural pesticides. Also, because of the short summer and the cold
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nights, few insect pests are encountered in the populated areas
which necessitate the use of pesticides. Water quality testing to
specifically identify these pollutants has not been carried out.
Heavy Metals — Analysis of existing data indicates that concen-
trations of heavy metals are low in surface waters of the study
area at points above population centers. Throughout the Gore
Creek drainage area, there are relatively low heavy metal con-
centrations. Water quality analyses of the Eagle River indicate
definite heavy metal pollution. The Federal Water Pollution
Control Administration (FWPCA) identified three sources of heavy
metal discharge into the Eagle River: 1) seepage from the New
Jersey Zinc Corporation's old holding pond, 2) direct flow from
the New Jersey Zinc Corporation's new holding pond, and 3) drain-
age from an abandoned mine located on the property of the New
Jersey Zinc Corporation, all near the town of Gilman. The pri-
mary heavy metal pollutants in the Eagle River are iron, zinc,
manganese and copper. Each of these is discussed below.
Most Colorado metal deposits are in the form of complex ore
including a mixture of iron, copper, lead, zinc and silver sul-
fides. Iron sulfide (pyrite) rapidly oxidizes in water, releas-
ing high concentrations of iron and sulfate. These chemicals
undergo further oxidation, forming ferric hydroxide (or yellow
boy), a yellow precipitate which is commonly found in streams
affected by acid mine drainage, and sulfate ions. Yellow boy,
in heavy concentrations, can destroy existing benthic fauna and
prevent establishment of new benthic organisms. Further, levels
of 2,000 ug/1 of iron, or above, can be injurious to health.
Concentrations of 460 ug/1 total iron have been found in Cross
Creek, and levels of iron ranging from 310 ug/1 to 900 ug/1
have been reported in the Eagle River. Deposits of yellow boy
(ferric hydroxide) are very evident in the Eagle River, covering
much of the substrate from above Minturn to Dowds Junction.
Zinc is the most common toxic heavy metal in Colorado waters.
Toxicity of zinc to fish varies considerably with the hardness of
water and with the fish species. Chronic exposure of some fish
species to sublethal levels of zinc makes them more resistant to
normally lethal concentrations that may occur periodically through-
out the year. No maximum suggested concentration of zinc has yet
been established for Colorado waters. Concentrations of zinc in
the Eagle River ranged from 130 ug/1 below the drainage from the
abandoned mine on the New Jersey Zinc Corporation property, to
310 ug/1 two miles downstream from the point of discharge. The
high zinc and iron concentration in this area eliminated all
bottom organisms. Biological recovery was noted near Dowds Junc-
tion.
To date, no manganese standards have been established in Colorado.
High levels of manganese have been measured since 1972 in Cross
Creek, with no seasonal patterns to correlate with high surface
water discharges. Since 1972, all reported levels of manganese
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in the Eagle River at the Avon bridge have been below 500 ug/1.
Several sampling periods recorded undetectable levels.
The toxicity of copper varies with the chemical composition of
the water and species. A maximum permissible level of 500 ug/1
has been proposed for the protection of livestock, but no
maximum concentration limits have yet been established for
Colorado waters to protect aquatic life. EPA has suggested that
the maximum allowable copper concentration should be 1/10 of the
96 hour LCso value for the m°st sensitive species. Although
brook and rainbow trout may not prove to be the most sensitive
species to copper toxicity, their 96 hour LCso data can be used
to arrive at a maximum allowable copper concentration of 10 to
25 ug/1. No detectable copper has been found in Gore Creek or
in the Eagle River at the Avon bridge since 1971.
Chlorine Residual — Chlorine is used widely as a disinfectant in
domestic water supply, sewage treatment, public and private swim-
ming pools, and in industry- It serves in many households as a
laundry additive. Until recently, the increased aquatic concen-
trations of chlorine were given little regard, although it has
been known for years that chlorine is a potent fish toxicant.
The primary source of chlorine in the surface waters of the study
area is the chlorine residual contained in the discharged
effluent from the sewage treatment facilities. This residual
results primarily from chlorination of the sewage effluent to
control bacterial levels. The residual may be found as free
available chlorine in the form of hypochlorous acid or hypochlor-
ite ion, but these forms, while strong disinfectants, are highly
reactive and are quickly dissipated. In most cases, chlorine
in the sewage effluent reacts with certain wastewater constituents
to form combined residuals. Reactions with ammonia commonly
occur, resulting in mono-, di-, or tri-chloramines. The presence
of cyanogen chloride residual is also common in sewage effluent.
These combined residuals are as toxic to aquatic organisms as is
free chlorine and, when discharged, their low reactivity allows
them to remain in solution for long periods of time.
Another form of combined residual chlorine formed during the
sewage treatment process are organo-chlorine compounds. These
compounds are formed through a complicated reaction between free
available chlorine and organic compounds found in domestic sewage
and industrial wastes. Recent evidence suggests the carcino-
genic (cancer-causing) effect of certain organo-chlorine complexes.
To date, only preliminary studies have been conducted on these
compounds, thus their toxic effect on aquatic organisms has not
been fully evaluated.
Both free available chlorine and combined residual complexes are high-
ly toxic to aquatic life. As with ammonia, the degree of toxicity
varies with the relative proportions of other substances in the water.
Table 16, on the following page,displays a summary of a portion of the
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TABLE 16
TOXICITY EFFECTS OF RESIDUAL CHLORINE
Species
Brook trout
Brook trout
Brook trout
Brook trout
Rainbow trout
Rainbow trout
Rainbow trout
Trout fry
ON AQUATIC LIFE
(CONTINUOUS EXPOSURE)
Average
Effect
Endpoint
7-day TL502
Absent in streams
67% lethality (4 days)
Depressed activity
96-hr. TL502
7-day TL502
Lethal (12 days)
Lethal (2 days)
Residual Chlorine
Concentration
(mg/1)
0.083
0.015
0.01
0.005
0.14-0.
0.08
0.01
0.06
29
'-SOURCE: .All data from: Brungs, W.A. , "Effects of Residual
Chlorine on Aquatic Life", JWPCF 45 (10), October, 1973,
(References for all data are given in this article)
•TL50: 50 percent survival in the specified time period
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research which has been conducted regarding the toxicity of
chlorine residual on cold water fish for continuous exposure
periods. Cold water fish are generally considered to be more
sensitive to chlorine than warm water species, and W. A. Brungs
of the EPA found that trout avoided concentrations as low as
0.001 mg/1. The proposed new Colorado Water Quality Standards
require an in-stream maximum level of 0.003 mg/1 for protection
of aquatic life in cold water streams, and a level of 0.01 mg/1
for warm water watercourses.
Data concerning chlorine residual levels in the streams of the
Upper Eagle Basin are not available.
Non-Point Pollution
Non-point pollution may be produced by water which has not pre-
viously been collected and/or contained, moving over land sur-
faces and through soils and rock formations, and discharging to
surface waters. As this occurs, the mechanisms of erosion,
sedimentation, leaching, absorption, dissolution, and precipi-
tation cause various organic and mineral contaminants to be
removed from their environment and carried to the receiving
stream. This water may originate from irrigation return flow,
groundwater sources, or precipitation.
The duration and frequency of precipitation occurrences have
major effects on the degree of some types of non-point pollution.
Thunderstorms, such as are characteristic of the study area, can
cause very high contaminant loadings on streams, but for very
short periods.
Agriculture — Mountain topography and a short growing season
limit the farming activity in the study area. Irrigated agri-
culture occurs along the Eagle River at various locations, from
Minturn to Avon, and downstream. Additional agricultural
sources of non-point pollution include livestock which may affect
stream turbidities by wading or by reducing ground-securing
vegetation on and near the stream banks.
Natural Sources — Natural non-point pollution is that which has
always occurred, and is not related to any man-induced activity.
Runoff from forested areas may contain some nutrients, but con-
centrations are likely to be significant only near roads and
trails where flow is less restricted. Constructing roads or
harvesting timber may cause erosion, resulting in an increased
sediment load on surface waters.
Industrial Pollution — The only major industrial waste dis-
charges to the Eagle River or its tributaries in the study area
originates from the mine tailings ponds of the New Jersey Zinc
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Corporation near Oilman. The ponds have long been considered to
be a source of pollution to the Eagle River, the primary con-
taminants being ammonia, zinc, iron, manganese, and copper. A
Colorado Department of Health report noted that (1) the concen-
trations of most of these materials in the Eagle River increased
significantly in the vicinity of the old tailings pond, and
(2) there was a notable reduction in aquatic species and total
organism count in the river downstream from the old pond. The
report summarized that groundwater seepage from this pond seems
to be the primary source of heavy metal contamination in the area.
Resultant concentrations of each of these constituents were above
the limits proposed for the new Colorado water quality standards
in the vicinity of the tailings ponds although concentrations
gradually decreased in a downstream direction. Below the Cross
Creek confluence, only recommended levels for iron and zinc were
exceeded. Below Avon, only the recommended zinc level was ex-
ceeded, which was the case as far downstream as the Town of
Eagle.
The new pond was also found to discharge ammonia and heavy metals
to Cross Creek, but only the ammonia content in Cross Creek had
significant effects on the Eagle River. The new pond, and/or
other unknown sources at times cause high levels of ammonia in
Cross Creek, which when combined with ammonia introduced into
the Eagle near the old pond, can cause un-ionized levels greater
than 0.02 mg/1 to occur. Although it is not suspected that this
situation occurs often, the ammonia load near the New Jersey
Zinc operation is significant, and should be taken into account
in establishing ammonia handling capacities and wasteload allo-
cations for the Eagle River and its tributaries.
Recreation -- The recent rise in popularity of four-wheel and
other off-the-road vehicle travel, has presented additional
environmental problems, including destruction of soil binding
vegetation. Four-wheel drive vehicles also create deep ruts in
non-surfaced roads especially when driven with chains in moist
soils. During snowmelt or heavy rainy seasons, water flows
down these ruts carrying away the loosened soil. Because of the
more favorable geography, most roads are located close to streams
which receive the muddy runoff.
Ongoing Construction — The primary water quality problem
associated with construction is suspended sediment. Construction
equipment can directly increase turbidity in surface waters by
traversing the streams or pushing soils into the streams. In-
creases in turbidity also occur after destruction of vegetation
and the loosening of normally compacted soils by construction
equipment which result in increased wind and water erosion.
Large projects, such as the construction on Interstate 70. must
minimize erosion by using specially-designed techniques and
equipment.
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Winter Road Maintenance — Winter climate and weather conditions
in Eagle County require frequent sanding of highways and commun-
ity streets. Road salt is mixed with the sand, at a four percent
ratio, to prevent sand scattering and to allow the sand to "key"
into the ice or snowpack. The State Highway Department applies
approximately 3,300 Ibs. of salt/sand mixture per mile of high-
way lane per storm. The salt eventually is dissolved and is
carried to water courses by storm runoff and snowmelt water,
thus increasing salinity content of these streams.
Urban Runoff Pollution — Urban runoff is that derived from
developed areas,particularly streets, parking lots, and roof tops,
and occurs during periods of precipitation and snowmelt. Pollu-
tants contained in urban runoff are similar to those found in
municipal sewage, except that concentrations are usually much
greater but occur for only short periods.
In the study area, the rare rainfall occurrences are brief and
intense, and pollutant loading on water courses may be consider-
able for very short periods. On the other hand, snowmelt occurs
during the warm hours of the day and may last several days or
weeks. Also, it should be realized that during the seasons when
most precipitation or melting (and urban runoff) occurs, streams
tend to be at a high stage and thus are less affected by the
pollution load than they would be during periods of low flow.
EXISTING FACILITIES
AND FLOWS'
The sewage treatment plants at Avon, Vail, and Red Cliff currently
operate under discharge permits. The location of these facili-
ties is shown in Figure 16. Other facilities located in the
study area include the holding ponds of the New Jersey Zinc Cor-
poration and two package aeration plants owned by Vail Associates.
Wote that the technical terms utilized in this section are
defined in the glossary section.)
Upper Eagle Valley Sanitation District
Description — The existing wastewater treatment facility for
the Upper Eagle Valley Sanitation District (UEVSD) is located at
Avon, Colorado. Gravity interceptor lines route raw sewage to
the plant from most of the developed areas within the boundaries
of the district. Wastewater from the Vail Water and Sanitation
District can be diverted into the interceptors for treatment at
the Avon plant, and sewage from the Arrowhead subdivision is
currently being pumped to the treatment works. The plant
usually operates on the conventional activated sludge principle,
-70-
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Figure 16
EXISTING INTERCEPTORS
MAY , 1976
UPPER EAGLE VALLEY
SANITATION DISTRICT
EXISTING FACILITIES
& I I
C3N3ULTINO
COLLINS
E NO IN CI II 4
COLOH A DO
-------
though sometimes the contact-stablilization process is used. Pri-
mary clarification is not provided. Following screening and grit
removal, the wastewater passes through enclosed aeration and final
clarification processes and chlorination prior to discharge to
the Eagle River. Secondary sludge receives aerobic digestion and
is then dewatered on drying beds. Dried sludge is land-filled or
sometimes used in agricultural applications.
The Avon plant original design capacity is two million gallons
per day (mgd) but has been evaluated as 1.65 mgd in the engineer-
ing portion of the Facilities Plan. The plant usually operates
below this capacity, but flows vary substantially on an hourly
and seasonal basis, typical for a resort area. The high flows
recorded in May through July are attributed largely to infil-
tration. Occupancy rates are significantly lower during this
period, however, stream flows are generally at their highest.
These high stream flows cause infiltration to the part of the in-
terceptor system which is located within the stream beds of Gore
Creek and the Eagle River. Repairs were made to the interceptor
system in 1975-1976, but infiltration was again high during the
spring of 1976. In May, 1976, late night flows of 1.22 mgd were
recorded at the treatment plant, and sewage strengths were highly
diluted. Recorded plant flows for 1975 are given in Table 17, on
the following page.
Present performance of the system is evaluated as good; however,
because operators are present only 8 to 12 hours per day, sludge
return cannot be adjusted for the peak flows. This may allow
a buildup of solids and potential solids discharge with the
effluent.
Effluent total ammonia concentrations measured at various hours
on January 17 through 18, and May 26 through 27, 1976, are shown
in Figure 17, following Table 16. The lower May values can be
attributed to: (1) weaker influent ammonia concentration due to
infiltration, and (2) the occurrence of some nitrification in the
treatment processes. The Colorado Department of Health (CDOH)
observed plant effluents containing as much as 11 mg/1 total
ammonia during the winter.
In the Eagle River downstream from the Avon Plant, un-ionized
ammonia levels as high as 0.028 mg/1 have been recorded, but
most documented data indicates that un-ionized ammonia concen-
trations in this vicinity seldom exceed 0.015 mg/1, and are
often considerably less.
Table 18, following Figure 17, displays the estimated average
daily ammonia loading which occurred in 1976 during the peak ski
season in January and during the winter in general. As can be
seen, even during the peak period, loadings for the Avon plant
were below maximum allocation levels for the Eagle River. In-
stream concentrations, resulting from plant discharge, were well
below the recommended limits.
- 72 -
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TABLE 1 7
l')7ri Tn-.itril W.-istrw.-iliT Vnliimcs for tin- Upni'r K.i^lr V.illi-y S.iiiil.il it
Dislricl .mil tin1 V.i i I W;i( IT .iiNl S.m i t .n ion l^istrirt
TKR I'.ACI.L VAI.LKY SANITATION DISTRICT
Month
January
February
March
Apri 1
Mny
.Itmo
Inly
August
September
October
November
Dei1 umber
Month
.lannary
February
March
April
May
.lune
July
August
September
October
November
December
Total for Dni 1 v Ili^.ti"
Month Average Flow
21,883,000 705,903 1,178,000
22,199,000 792,000 909,000
28,509,000 919,645 1,101,000
23,193,000 773,100 1,002,000
28,203,000 909,000 1,171,000
40,301,000 1,343,000 1,594,000
39,226,000 1,265,354 1,785,000*
24,699,000 796,741 1,090,000
16,830,000 561,000 687,000
14,080,000 454,193 572,000
18,956,000 631,866 965,000
20,113,400 648,819 1,002,000
VAII, WATER AND SANITATION DISTRICT
9 •>
Total for Daily High" l,ow~
Month Average Flow Flow
28,276,000 912,129 1,224,000 687,000
26,793,000 958,000 1,031,000 847,000
30,044,000 969,161 1,133,000 695,000
23,002,000 766,733 988,000 594,000
21,780,000 702,580 943,000 465,000
30,826,000 1,022,533 1,159,000 917,000
29,649,000 956,419 1,215,000 741,000
27,158,000 876,064 1,121,000 667,000
22,667,000 755,566 970,000 609,000
18,773,000 604,290 686,000 502,800
13,694,000 456,467 1,035,000 105.000*
27,458,000 885,742 1,295,000* 558,000
1 Based on records of each district, flows in gal. per dav
2 Maximum or minimum daily flow recorded for the month
3 Volume unknown
4 Values are 15 percent low due to error in plant metering device
5 Values are 40 percent low due to error in plant metering device
* Underlined values represent the maximum or minimum dailv flow recorded
Low
!•' 1 ow
498,000
742,000
783,000
651,000
637,000
1,117,000
946,000
613,000
485,000
375,000*
432,000
462,000
Water
Production
32,7.01,000
31,407,000
32,430,000
19,434,000
15,090,000
19,220,000
30,647,000
35,003,000
26,073,000
15,058,900
3
26,966,700
for the year
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Figure 17
UPPER EAGLE VALLEY SANITATION DISTRICT
EFFLUENT AMMONIA CHARACTERISTICS
10
8
ro
x
o 4
Jan. 17-18,1976
May 25-26,1976
No Data
12am 4am 8am Noon 4pm 8pm 12am 4am 8am Noon
Time of Day
SOURCE: MSI Inc , 1976
-------
TABLE 18
ESTIMATED AMMONIA LOADING IN 1976 - AVON PLANT
Flow
Conditions
Pe*k Ski
Season, 1976
Eagle River
Daily
Plant
Flow
(mgd)
1.202
Total Ammonia
Discharged
(lb/day)2
106
Dec. - July
Wasteload
Allocation
(lb/day)1
245
Resulting Stream
Total Ammonia
Con. (mg/1)3
(average)
0.486
Total Steam Ammonia
Allowed to Maintain
Un-ionized Con. Less {
than 0.02 mg/1 (mg/1)
1.27^/3.975
Normal Winter
Flows, 1976
Eagle River
0.9
80
245
0.38
I NOTES:
iprom NHPZ, 1975
^Based on flow and ammonia measurements made at plants in January, 1976
^Does not include any background ammonia present, or effects of other sources (N. J. Zinc)
^Based on historic 7-day/10 year low flows, pH, and temperature which create the most adverse loading
conditions for winter
^Based on historic 7-day/10 year low flows, pH, and temperature for January (N.H.P.Q., 1975)
Based on historic 7-day/10 year low flows for January
Based on 1975 flow data corrected for metering error
SOURCE:
COM Inc., M & I Inc., NHPQ (1975)
-------
Permit Requirements — The requirements of the UEVSD Discharge
Permit are shown in Appendix L . of particular note are the
ammonia restrictions which were taken directly from wasteload
allocation determined in a report entitled Population Capacity
of the Eagle Valley Based on Ammonia Toxicity prepared for Vail
Associates. The ammonia wasteload allocations are based on a
maximum allowable in-stream concentration for un-ionized
ammonia of 0.02 mg/1.
Vail Water and Sanitation District
Description — The Vail Water and Sanitation District Wastewater
Treatment Plant is located near the west boundary of the town of
Vail and discharges to Gore Creek. The facility normally treats
all sewage for Vail, but during the ski season, if peak loads
would cause the plant's capacity to be exceeded, the excess flow
can be bypassed downstream through UEVSD interceptors to the Avon
plant. Sewage originating in the Bighorn community, although a
part of the Upper Eagle Valley Sanitation District, is frequently
treated at the Vail facility.
The facility is an activated sludge plant, operating on the
conventional or contact-stabilization principle. Following
screening and grit removal, sewage passes directly to aeration,
followed by final clarification, chlorination, and discharge to
Gore Creek. Primary clarification is not provided. Waste sludge
is thickened by flotation, dewatered with vacuum filtration and
hauled to a landfill site.
Performance -- The rated capacity of the Vail plant is 1.5 mgd,
and, according to the district records (as shown in Table 19 on
the following page), this flow was not exceeded on a daily basis
in 1975. However, the flow measuring device has been found to be
in error, and the actual plant flows are estimated to have been
40 percent greater than those recorded. The plant design capacity
was therefore exceeded during portions of January and December,
1975. Average daily flows as high as 2.75 mgd were measured in
January of 1976. Highly variable hourly flows have often exceeded
plant capacity during certain times of the day, particularly
during the ski season. Flows vary considerably on a seasonal
basis, but a considerable portion of spring and summer flows are
due to infiltration. In May, 1976, night-time flows as great as
1.28 mgd were observed, indicating severe infiltration. Sewage
strengths were also extremely low.
The Vail treatment plant also is staffed only eight hours per day
(12 hours during ski season). The high peak flows occurring in
the evening have, in the past, caused periodic solids build-up
in the tanks and occasional discharge of these solids with the
effluent. Effluent total ammonia levels measured periodically on
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TABLE 19
ESTIMATED AMMONIA LOADING IN 1976 - VAIL PLANT
Flow
Conditions
eak Ski
Discharge
Point
Gore Creek
Daily
Plant
Flow
(mgd)
2.751
Total Ammonia
Discharged
(lb/day)l
177
Resulting Stream
Total Ammonia
Con. (rag/1)2
(average)
2.675
Total Steam Ammonia
Allowed to Maintain
Un-ionized Con. Less
than 0.02 rag/1 (mg/1)3
0.933/3.164
Season, 1976
Normal Winter
Flows, 19766
Gore Creek
1.4
99
1.32:
.93:
NOTES: Ifiased on flow and ammonia measurements made at plants in January, 1976
2
Does not include any background ammonia present, or effects of other sources (N. J. Zinc)
^Based on historic 7-day/10-year low flows, pH, and temperature which create the most adverse loading
conditions for winter
Based on historic 7-day/10 year low flows, pH and temperature for January (N.H.P.Q., 1975)
-*Based on historic 7-day/10 year low flows for January
"Based on 1975 flow data corrected for metering error
SOURCE:
COM Inc. , M & I Inc., NHPQ (1975)
-------
January 17 through 18 and May 25 through 26 are shown in Figure 18
on the following page. As was characteristic of the Avon plant,
the May values are nuu-h lower t \\.\\\ t hose tot .i.-um.u y , whi«-l> .<.|.IM\
is attributed to extremely low influent ammonia eoneontrnlions
caused by low wastewater flow and high infiltration, and the oc-
currence of nitrification in the treatment processes. The data
indicated that no in-plant nitrification occurred during the
January 17-18 sampling period. Total ammonia levels in the range
of 12 to 21 mg/1 in the Vail plant effluent were measured in
February, 1975, and also measured 7.2 mg/1 in April of that year.
Due to the high ammonia levels discharged from the Vail plant dur-
ing certain times of the year, and the relatively low capacity of
Gore Creek to accept these discharges, high levels of un-ionized
ammonia are attained in Gore Creek downstream from the plant
discharge point. During February, 1975, un-ionized levels as
high as -07 mg/1 were measured (average values were greater than
.04 mg/1). The Colorado Department of Health has also measured
un-ionized ammonia levels as high as .049 mg/1 in Gore Creek at
its confluence with the Eagle River.
Winter low flow months are the most critical time periods
regarding ammonia toxicity, since the highest levels are observed
at this time. During warmer periods, ammonia is more toxic, but
in the past, lower sewage loads, higher streamflow, and in-plant
nitrification have resulted in a much lower ammonia content in
Gore Creek in the spring and summer.
Table 19 also gives the estimated average ammonia loading which
occurred in 1976 during the peak ski season in January and during
the winter in general.
Based on research of the toxic effects of residual chlorine on
trout, an in-stream maximum allowable level of 0.003 mg/1 is
currently being considered for adoption by the CDOH. Chlorine
residual discharge at the Vail plant in accordance with the
present permit (0.5 mg/1) will probably cause the recommended
in-stream limit to be exceeded much of the year, particularly in
the winter.
Permit — The stipulations of the Vail Water and Sanitation Dis-
trict Discharge Permit are shown in Appendix L . NO stipulation
for ammonia was included in the new permit, which was issued late
in 1976.
Red Cliff Water and Sanitation District
Description — The Red Cliff Water and Sanitation District sewaae
treatment facility is located at the confluence of the Eagle River
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10
8
I
ro
2
0
Figure 18
VAIL WATER AND SANITATION DISTRICT
EFFLUENT AMMONIA CHARACTERISTICS
Jan. 17-18,1976
-H
12am 4am Sam Noon
May 25-26,1976-7
4pm 8pm 12am 4am 8am Noon
Time of Dny
SOURCE: M 81 Inc , 1976
-------
and Homestake Creek. The plant and the collection system were
completed in 1972. The plant is an open package type operating
on the contact-stabilization process. The unit includes a manual
bar screen, contact tank, stabilization tank, a final clarifier,
chlorine contact chamber, and an aerobic digestion tank. Drying
beds are provided for sludge dewatering.
Performance — The existing collection lines, while only four
years old, are subject to severe infiltration/inflow problems.
It has been estimated that raw sewage accounts for only about
20 percent of the total flow in the collection system.
Infiltration has been attributed to substandard sewer construction
and inadequate inspection. The alluvial soil is rocky and has a
high water table. Although concrete pipe was specified, clay
pipe was used. The amount of infiltration allowed by the CDOH
is currently exceeded by more than 20 times in July. In winter
water service lines are bled to the sewer system to prevent line
freezing, and this volume equals the summer infiltration flow.
The Red Cliff package treatment plant is designed to treat .07
mgd, but due to infiltration/inflow in the sewers, plant flows
are consistently three to five times this amount. Due to this
high hydraulic loading, the plant is not able to operate properly,
and much of the "reduction" in pollutant concentrations from raw
sewage can be attributed only to dilution.
Since adequate biological oxidation and assimilation reactions
do not take place within the plant, the organic and suspended
solids content in the sewage are not actually removed. Conse-
quently, much of the time, raw sewage is discharged, in diluted
form, to the Eagle River. If the hydraulic loading problem is
corrected, the plant would still be inadequate, because the unit
is .not covered or otherwise protected, chlorine contact time is
inadequate, and the aerobic digester cannot provide sufficient
volatiles reduction. No provision has been made for sludge dis-
posal in the winter. Aeration capacity is inadequate and treat-
ment cannot be isolated without shutting down the entire process.
The plant was not designed with either safety considerations or
access to equipment in mind.
Permit — The stipulations of the discharge permit are included
in Appendix L . This permit expired in September, 1976, and the
new permit is not expected to be significantly more restrictive.
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Other Facilities
Description -- The NJZ Corp. maintains two tailings ponds,
referred to as the old and the new pond. The new pond discharges
directly to Cross Creek through a series of outlet works and a
channel. Sewage from the town of Gilman is passed through septic
tanks and chlorinated. It is then mixed with mine tailings in
the pipeline, en route to the new pond.
The old pond no longer receives waste material, but lime is
mixed with seepage water from this pond, and the slurry is pumped
through the tailings pipeline en route to the new pond. The lime
is used to raise the pH of the tailing waste to facilitate pre-
cipitation of metals and enhance settling. (Residence time in
the pond is two to three days and the average inflow rate is
1700 gallons per minute when the mill is in operation.) The tail-
ings wastes and Gilman sewage receive no further treatment prior
to discharge to Cross Creek.
Performance — The new pond discharges highly variable amounts of
iron, manganese, lead, zinc, and ammonia to Cross Creek, yet only
manganese and ammonia levels increased significantly in the
stream, and the ammonia increases were not consistent. In one
measurement, the ammonia level was already at a high value up-
stream from the discharge point. The total ammonia contributed
either by the pond or unknown upstream sources was, in some cases,
great enough to cause un-ionized levels in excess of 0.02 mg/1 to
occur in Cross Creek, and when combined with ammonia introduced
into the Eagle River near the old pond, excessive un-ionized
levels also occurred in the Eagle River.
Un-ionized ammonia levels in excess of 0.02 mg/1 in Cross Creek
and the Eagle River have been verified by the Colorado Depart-
ment of Health. Any increases in metal content in the Eagle
River beyond the Cross Creek confluence were mostly minor, and
in many cases, the amounts decreased, probably due to dilution.
Total organism counts have been shown to increase in the Eagle
River beyond its confluence with Cross Creek.
Measured data demonstrated that the NJZ Corp. at times, but not
consistently, exceeds its discharge permit limitations for cop-
per, iron, and manganese. In the Eagle River, concentrations
of iron and zinc were consistently above the recommended levels
of the proposed Colorado Water Quality Standards, both upstream
and downstream of the Cross Creek confluence, indicating that
the primary source was upstream from Cross Creek. Therefore any
increases in iron and zinc concentrations in Cross Creek caused
by discharge from the new pond were minor.
Permit — The discharge permit for the new tailings pond expires
July, 1978. The discharge requirements of the permit are shown
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in Appendix L. The NJZ Corp. has recently been issued a second
permit for a controlled groundwater discharge from a mine. The
discharge point is on Turkey Creek upstream from Red Cliff. No
treatment is provided to the discharged liquid, which contains
no tailings, excessive metals, or other waste material.
The only other sewage treatment facilities upstream from the
study area are two package aeration plants located on Vail Moun-
tain, one at the Mid-Vail Restaurant and another at the Lionshead
Restaurant in the Eagles Nest Area. Both are owned and operated
by Vail Associates, and both are non-discharging. Disposal is
accomplished through leaching and percolation.
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II. THE ALTERNATIVES AND THE PROPOSED ACTION
The purposes of this chapter are to:
- Present the alternatives evaluation process and the
integration of both the engineering and environmental
analyses
- Discuss each of the four alternatives selected for
further environmental analysis
- Describe the process by which the final selection
was made
THE ALTERNATIVES EVALUATION
PROCESS
A 201 Facilities Plan has the multiple goals of:
- Identification of future wastewater facility demands/needs
for a 20 year planning period
- Preparation of an environmental analysis which, first,
sets criteria for the selection of alternative treat-
ment methods and treatment plant configurations/sizes
and, second, analyzes and compares the impacts of
various selected alternatives
- Integration of engineering and environmental
analyses to ensure full consideration of environ-
mental and cost/technological issues
Engineering and Environmental Integration
In the 201 planning'process, when the EIS and facilities plan are
performed concurrently, it is referred to as a "piggyback" EIS
approach. The purpose is to bring environmental issues to the
forefront during early stages of the decision-making process.
During the initial stage of the Upper Eagle Valley facilities
planning process, environmental data was collected and analyzed,
including population and land use projections, geology and soils,
biological inventories, and hydrologic and water quality data.
These data revealed the environmental hazard areas (snow avalanches,
100 year floodplain, debris fans, rockfall areas) as well as
environmentally sensitive areas (culturally significant, densely
populated, natural riparian vegetation, and wildlife migration
areas) which should be avoided or protected during the construction
and operation stage of treatment facilities and pipelines.
Each facet of the area's existing environment (and future environ-
ment in the case of population/land use/air quality) was described
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in order to ascertain the engineering constraints. The environ-
mental aspects were given consideration through:
•
- Presentation and discussion at public 201 Advisory
Committee and combined Sanitation District Meetings.
Major topics included population and land use,
treatment processes, water quality and ammonia
standards, and infiltration and system renovation.
- Roundtable discussions, attended by both the environ-
mental and technical personnel preparing each analysis.
Major considerations were: evaluation of present
plant sites for future expansion; analysis of equip-
ment and procedures presently used, in terms of
adequacy; distribution of future population; treat-
ment processes, and sludge disposal methods, in-
cluding land treatment of either sludge or effluent;
and consideration of alternative sites, for future
plants.
The outcome of the initial discussions resulted in the ten alter-
natives shown in Table 23, on the following page. These were then
presented to the following groups:
- The 201 Advisory Committee
- Vail Water and Sanitation and Upper Eagle Valley
Sanitation Boards; Minturn Town Manager; and
representatives' of the Red Cliff Water and Sani-
tation District
- The public, at a formally announced "Public Hearing"
The sizing and locational alternatives were discussed at length.
The ten alternatives were discussed and evaluated, and some
solutions were discarded, while others were combined. The result
was the set of four alternatives and three subalternatives
discussed in the following section.
DESCRIPTION OF
ALTERNATIVES
Selection of the sewage system imnrovements which will adequately
meet the needs of the projected population growth required
consideration of various alternatives for plant siting, plant
sizing, and the need and location of new and/or enlarged inter-
ceptors. In addition, various treatment processes were investi-
gated to determine which was the most economical and flexible.
This section describes the facilities and process alternatives
which were selected for in-depth environmental analysis, and
from which the preferred alternative was selected.
Alternatives were evaluated for the Upper Eagle Valley Sani-
tation District and the Vail Water and Sanitation District.
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TABLE 20
20i "AGILITIES PLAN ALTERNATIVES
Des ignat ion
prior To
Final Selection
Description
Evau la t ion
New lie s 1 gna t 1 on
For
Final Evaluation
Alternative 1
Alternative 2
Alternative 3a
Alternative 3b
Alternative 4
Alternative 5
No expansion or upgrading of area treatment
works. "No project" alternative.
Abandon Vail and Avon plants. Construct a
new 6.2 mgd plant now to meet 1985 demands,
and expand to 8.8 mgd in 1985 to meet 1995
projected demands.
Upgrade Vail at present capacity. Construct
new 2.6 mgd plant at Dowds Junction. Expand
and upgrade Avon Plant now to 2.5 mgd (1985
flows) and in 1985 to 4.7 (1995 flows).
Abandon Vail. Construct new 4.1 mgd plant
at Dowds Junction. Expand and upgrade Avon
Plant now to 2.5 rogd (1985 flows) and to
4.7 mgd in 1985 to meet 1995 flows.
Expand and upgrade Vail now to 3.0 mgd with
flow equalization. Expand and upgrade Avon
now to 3.5 mgd (1985 flows) and to 5.8 mgd
in 1985 to meet 1995 flows.
Expand and upgrade Vail to 3.0 mgd with
flow equalization. Expand and upgrade
Avon plant to 3.5 mgd. Construct new 2.3
mgd plant in 1985 at downstream site
(1995 flows) .
Although impractical,
this"solu11 on" must be
considered according to
NEPA guidelines.
Not cost effective in
that present treatment
works are not antiquated
and may be expanded and
upgraded more economically
An acceptable, cost
effective alternative.
Selected for further
eva1ua t ion .
An acceptable, cost
effective alternative.
Selected for further
evaluation.
An acceptable, cost
effective solution.
This alternative has the
advantage of leaving
several options open in
1985 to meet 1995 needs
(discussed below).
This alternative is
viable. The only differ-
ence between this and the
prior alternative is ex-
pansion of Avon vs. a new
downstream plant. Thus, an
option mav be left open.
Alternative
Eliminated from
further c <_• n --
s iderat ion .
Altern.it i \
Altern-
A 11 e r r.. i r i
Alternaci\
111' r n .!': i v e
Alternative 7
Alternative 8
Alternative 9
Alternative 10
j i m t- as Alternative 4 except detention
time at Vail decreased. No bypass to
Avon Plant.
Same as Alternative 5 except detention
time at Vail decreased. No bypass to
Avon Plant .
This alternative was included to allow for
the withdrawal of Vail from the 201 plan if
desired.- No expansion of Vail. East Vail
flow bypassed to Avon. Upgrade and expand
Avon to 3.5 mgd (1985 flows). Construct
2.3 mgd plant in 1985 downstream to meet
1995 flows or expand Avon facility in
1985 to meet 1995 flows.
Construct a 8.8 mgd land treatment facility
now to meet 1995 flows.
Expand and upgrade Vail to 3.0 mgd with
flow equalization of bypass. Construct a
5.8 ragd land treatment facility now at a
downstream site, to meet 1995 flows.
Ivaluated as a sun-
alternative, nut a
true alternative.
Evaluation as a sub-
alternative, not a
true alternative.
Evaluated as practical
at the time of the
hearings. Questions of
equity and financing
might have caused Vail
to withdraw from the
201 area.
Not cost effective.
Storage and transpor-
tation problems and
short growing season.
Not cost effective. The
plant may be too large
if growth does not
occur. Storage problems.
A 11 e r ••> a1 • •
Alternatlv Id
Al tc ma : i •
Elimina •„•= r1
from f u r '. i (.•:
considerati or.
E 1 inin.i t •',
from furtli
consider.-, t
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Most cf the alternatives involved a coordinated effort between
the two districts, since their sewage treatment works are physi-
cally connected. Alternatives were not considered for Red Cliff
since previously recommended improvements were evaluated and
were considered as part of the 201 facilities clan. They are
discussed and evaluated in Appendix N.
Initially, a variety of siting and sizing options were evaluated.
The evaluation and selection process resulted in an elimination
to the most feasible ten alternatives. These original ten al-
ternatives were presented, evaluated and discussed. Following
these meetings, input from local, state, and federal officials
and the general public was received, and the ten were combined
or eliminated. The final selection of four alternatives, and
three subalternatives, is discussed below. The alternatives have
two components: (1) upgrading and expanding existing plants
and/or constructing new facilities and interceptors, and (2) re-
placing portions of the existing interceptor (pipeline) system
in order to increase overall flow capacity. Interceptor replace-
ment generally consists of removing existing pipe and installing
new pipe of larger diameter, as required for the projected flows,
at the sane grade and alignment. Parallel rather than new sewer
lines may be used in some locations, but replacement of existing
pipe at the same location minimizes the need for additional space
and easements. A "no-project" alternative has been included,
because its consideration is reauired by NEPA guidelines. A no-
funding alternative is evaluated as part of the chapter on
Institutional and Financial Considerations and Impacts.
Alternative 1
The Vail plant would remain at its present capacity (1.5 mgd) ,
but would be upgraded to comply with discharge standards. All
sewage flows generated in Vail and Bighorn in excess of 1.5 mgd
would then be treated at a downstream location. Sludge handling
equipment would be removed, and waste activated sludge conveyed
downstream with the bypassed raw sewage through the interceptor
lines. A new 2.6 mgd plant would be immediately constructed
between Vail and Avon, at Dowds Junction, with effluent dis-
charge to the Eagle River. This facility would have ammonia
removal capability, and all waste sludge would be conveved to
the Avon plant. The new Dowds Junction plant would be designed
to treat all sewage generated to the year 1995 in the Gore Creek
drainage, except for that treated at the Vail plant. Since
most of the projected Gore Valley growth will take place by
1985, stagina is not practicable.
The Avon facility would be expanded to 2.5 mcd immediately, and
to 4.7 mgd in 1905. It would treat all sewage originating in
the upper Eagle drainage, excluding Gore Creek, and including
waste sludge from the Dowds Junction plant. The plant would
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have ammonia removal, flow equalization, and sludge handling and
disposal facilities.
Alternative 1 would require extensive interceptor replacement,
particularly in the Gore Creek drainage below Vail (only 1.5 mgd
would be retained at Vail with all other flows, including hourly
peaks, bypassed downstream). Some interceptor segments between
Dowds Junction and Avon as well as in the Vail and Bighorn areas
would also require replacement. Total distance of new lines for
this alternative is 13.12 kilometers (8.15 miles). Alternative 1
is shown in Figure 19,on the following page.
Alternative 2
In this alternative, the Vail facility would be abandoned as soon
as a new plant is completed, between Vail and Avon at Dowds
Junction, The plant design capacity would be 4.1 mgd, and would
provide treatment for 1995 flows from the entire Gore Creek
drainage area (Bighorn, Vail, and West Vail). As with Alterna-
tive 1, staging would not be desirable since 1995 populations in
the Gore valley are projected to be only slightly hiqher than in
1985. Ammonia removal would be provided, and all waste sludge
returned to the interceptor system for conveyance to the Avon
plant.
The Avon plant would be expanded to 2.5 mgd by 1985 and to 4.7 by
1995. It would be sized, staged, and provided with ammonia
removal, flow equalization, and sludge facilities (as in Alterna-
tive 1) .
Interceptor replacement would include that required for Alterna-
tive 1, with the additional replacement of lines from the Vail
plant downstream to the new plant. Total length of replacements
is 13.66 kilometers (8.49 miles). For all alternatives, new
interceptor replacements would be carried out immediately and
designed for 1995 flows. Alternative 2 is shown in Figure 20.
following Figure 19.
Alternative 3
This alternative would involve immediate expansion of the Vail
plant to 3 mgd, to treat 1995 flows from Vail as well as Bighorn.
The plant could either be designed to treat the peak flows that
occur during the ski season, Alternative 3c,d, or peak flows
could be equalized and/or bypassed downstream to the Avon plant,
Alternative 3a,b. Ammonia removal would be provided at the Vail
plant, and all waste sludge would be returned to the interceptor
system for conveyance to the Avon facility.
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Figure 19
EXPAND 8 UPGRADE
TO 2.5 MGD 1985
TO 4.7 MGD 1995
NEW PLANT
2.6 MGD 1995
UPGRADE
1.5 MGD 1995
INTERCEPTOR REPLACEMENT REQUIRED
MAY , 1976
UPPER EAGLE VALLEY
SANITATION DISTRICT
SITE ALTERNATIVES
ALTERNATE NO. I
& I I IMC
COMIULTIKO
rOHT C ILL I MB
COLOHADO
-------
Figure 20
EXPAND 8 UPGRADE
TO 2.5 MGD 1985
TO 4.7 MGD 1995
INTERCEPTOR REPLACEMENT REQUIRED
MAY .
UPPER EAGLE VALLEY
SANITATION DISTRICT
SITE ALTERNATIVES
ALTERNATE NO.2
& I I
(HOIMCIBS
TOUT cm i. INS
COLOUA DO
-------
The Avon plant would be immediately expanded to 3.5 mgd to treat
all sewage generated downstream from the Vail plant through 1985.
It would provide ammonia removal, flow equalization, and sludge
handling and disposal. To meet the projected flows from the
same tributary area to the year 1995, the Avon plant would be
expanded in 1985 to a capacity of 5.8 mgd. As an alternative to
the 1985 expansion, a new plant could be constructed downstream
in the vicinity of the Squaw Creek confluence. The facility
would be designed for a flow of 2.3 mgd plus any additional
identified flows for any new development between Avon and Squaw
Creek. Equalization for peak flows would be provided at the
Avon plant, and the new plant would also have ammonia removal and
sludge handling and disposal facilities. The decision to either
enlarge the Avon facility or build a new plant should be made
later, when the expansion becomes necessary. For simplicity, the
various options offered with this alternative are summarized into
four subalternatives:
Alternative 3a:
Alternative 3b:
Alternative 3c:
Design to bypass peak flows at the Vail
plant, and enlarge the Avon plant in 1985.
Design to bypass peak flows at the Vail
plant, and construct a downstream plant in
1985.
Design the Vail plant to treat peak flows,
and enlarge the Avon plant in 1985.
Alternative 3d: Design the Vail plant to treat peak flows,
and construct a downstream plant in 1985.
Interceptor replacements for 3a and 3c would be less than with
either Alternative 1 or 2, since more sewage is treated at
upstream locations. A completely new interceptor would be needed
downstream for Alternatives 3b and 3d from Avon to the new plant.
The total new interceptor requirements for 1995 would be:
Alternative 3a: 8.45 kilometers (5.25 miles)
Alternative 3b: 18.57 kilometers (11.54 miles)
Alternative 3c: 9.98 kilometers (5.58 miles)
Alternative 3d: 18.12 kilometers (11.26 miles)
The approximate placement of these interceptor lines is depicted
on Figures 21 and 22• on the following pages.
Alternative 4
This alternative would provide for improvement and expansion of
sewage facilities in the Upper Eagle Valley Sanitation District
-90-
-------
Figure 21
EXPAND a UPGRADE
TO 3.5 MOD 1985
TO 5.8 MGD 1995
EXPAND 8 UPGRADE
TO 3.0 MGD 1995
FLOW EQUALIZATION)
INTERCEPTOR REPLACEMENT REQUIRED
MAY , 1976
UPPER EAGLE VALLEY
SANITATION DISTRICT
SITE ALTERNATIVES
ALTERNATE NO. 3a,3c
41 i INIC
CONSULTING
FOBT COLLINS
COLOR* DO
-------
Figure 22
EXPAND a UPGRADE
TO 3.5 MGD 1985
FLOW EQUALIZATION
NEW PLANT
2.3 MGD 1995
•i>
.o
I
INTERCEPTOR REPLACEMENT REQUIRED
INTERCEPTOR
VAI
EXPAND 8 UPGRADE
TO 3.0 MGD 1995
(FLOW EQUALIZATION)
UPPER EAGLE VALLEY
SANITATION DISTRICT
SITE ALTERNATIVES
ALTERNATE NO. 3b,3d
MAY, 1976
JSxl & I
COMIULTIIIO
ro»T COLLIIII
I IMC
I HOIH *I •(
COLO*A DO
-------
only. its intent is to allow the Vail Water and Sanitation Dis-
trict, should it so elect, to pursue an individual course of
action under its own schedule, remaining separate from the UEVSD,
Bighorn's sewage flows would be bypassed around the Vail plant,
and routed to the Avon plant.
The Avon plant would be immediately expanded to 3.5 mgd to
accomodate the 1985 projected flows. Ammonia removal, flow
equalization, and sludge handling and disposal would be provided.
In 1985, the Avon plant could be expanded or a new plant could
be constructed at a downstream site near Squaw Creek. The plant
would be designed for a flow of 2.3 mgd with possible additional
capacity needed for new development between Avon and Squaw Creek.
Interceptor replacement would be just slightly more extensive
than that required under Alternative 3, since an additional
0.6 mgd would be in the lines in 1995 (from Bighorn). Total
length of new or replaced interceptor lines would be 19.52
kilometers (12.13 miles). Alternative 4 is shown in Figure23,
on the following page.
Alternative 5
The "No Project Alternative" assumes that no improvements whatso-
ever are made to the existing facilities of either district.
It is also assumed that development and growth will occur as
projected. This alternative illustrates the environmental
consequences of not providing sewerage system improvements for
anticipated growth. The alternative of no EPA funding, with
the Sanitation Districts then deciding to fund their expansions
and improvements themselves, is addressed in the Chapter,
Institutional and Financial Considerations and Impacts.
THE SELECTION OF A PREFERRED
ALTERNATIVE
The four alternatives selected for additional in-depth evaluation
were discussed at length at meetings of: the Vail Water and
Sanitation District Board, the Upper Eagle Valley Sanitation
District, the Eagle County Board of Commissioners and the 201
Advisory Committee. Alternatives 1, 2, 4, and 5 were rejected,
as were alternatives 3c and 3d. Of the remainder (3a and 3b)
the specific subalternative to meet projected 1995 flows has not
been determined in order to leave open the option as to whether
to expand Avon or to build a new plant at a downstream site in
1985. The Squaw Creek plant site and service area downstream of
the Avon plant is not presently within the Upper Eagle Sanitation
District service boundary and is outside the study area for the
EIS. Therefore, a decision of whether to expand the Avon plant j.-.
1985 or construct a new plant near Squaw Creek in 1985 will not b.
made at this time. This decision will await future county devel-
opment plans and will require additional environmental assess-
ments outside the study area and the scope of this study.
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Figure 23
EXPAND a UPGRADE
TO 3.5 MGD 1985
NEW PLANT
2.3 MGD 1995
INTERCEPTOR REPLACEMENT REQUIRED
NEW INTERCEPTOR
MAY, 1975
UPPER EAGLE VALLEY
SANITATION DISTRICT
SITE ALTERNATIVES
ALTERNATE NO. 4
4 I. IIMC
COntULTIMO
COLL I MS
COLOIIA DO
-------
TREATMENT
PROCESSES
In this section, the recommended treatment processes are described
and evaluated, and alternative methods are briefly discussed. The
technical terms are defined in the Glossary section.
Preliminary and Primary Treatment
Proposed System — Preliminary treatment at the UEVSD plant will
consist of comminution with a manual screen bypass, preceded by
aerated grit removal. At the existing Vail facility, mechanical
screening without grit removal is proposed. Primary clarifi-
cation will not be provided at any location; sewage will pass
from preliminary treatment directly to the aeration basins.
Evaluation — Comminutors are commonly used in smaller treatment
plants,and while they are simple to operate, they are also
susceptible to periodic breakdown. The principal advantage is
that all solid material remains in the wastewater, thus no waste
product must be handled. A mechanical screen is a simpler device,
but requires greater attention and produces a waste product.
Since grit removal is not proposed for the Vail plant, the screen-
ings will be the only waste product produced.
Grit removal processes prevent excessive amounts of solids from
entering the biological processes. A build-up of these
non-degradable solids can displace mixed liquor and reduce
process efficiency. Grit removal is essential when the sewage
passes through long interceptor lines which are susceptible to
infiltration and inflow. Aeration of the grit facilities at the
downstream plant is highly recommended, since the incoming
sewage may reach septic conditions in the long interceptor line,
particularly in the summer. The aeration will freshen the waste-
water and help minimize odors.
Primary settling customarily precedes aeration when the conven-
tional activated sludge method (as proposed) is used. However,
primary clarification can often be eliminated if the raw waste
is largely domestic, contains no excessive grease, and grit re-
moval is provided. Conventional activated sludge treatment is
used successfully in Colorado in many locations (including Avon
and Vail) without primary clarification. An advantage of the
exclusion of primary settling is that the production of primary
sludge is eliminated as is the need for additional sludge hand-
ling processes, equipment, disposal sites, and operator atten-
tion. However, the additional solids loading which will be
imposed on the downstream plant(s) by the discharge of waste
sludge to the interceptors at the upstream facilities may justify
-95-
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economically the use of primary treatment, when weighed against
the additional aeration (including aerated grit removal) which
will otherwise be needed. Either method is environmentally
sound; the choice is one of economics.
Other Alternatives — If primary clarification is used, the
sludge produced is more easily dewatered than secondary sludge,
and in many plants the two sludges are mixed to provide more
efficient dewatering of secondary sludge. Primary sludge lends
itself well to anaerobic digestion, discussed later in this
section.
Secondary (Biological) Treatment
Proposed Systems — Secondary treatment will be accomplished by
the conventional activated sludge process, followed by final
clarification. New aeration basins and clarifiers will be used
at the Vail plant. Because of the limited space available and
highly variable loadings which must be handled by the Vail
plant (under some of the site alternatives), aeration with pure
oxygen is proposed as an alternative for this facility- Aeration
will be provided with submerged turbines at the other treatment
works.
Evaluation — The activated sludge process is the most feasible
secondary treatment method for this application, since a high
degree of treatment can be obtained and a minimum amount of
space is required. The conventional mode is the most commonly
used technique for plants handling flows greater than 1 mgd.
Biological processes are very susceptible to cold weather
effects, which include retardation of oxidation and assimilation
reactions and reduced oxygen transfer rates. Influent tempera-
tures near 5 degrees Centigrade, such as have been recorded at
Avon, require that certain design considerations be made, in-
cluding reduced organic loading rates and the enclosure of the
process in a heated building. Final clarifiers should be
designed to allow for very conservative overflow rates. Both
aeration tanks and clarifiers can be made rectangular to mini-
mize required space and enclosure costs. Aeration with diffused
air allows less exposure of the liquid to cold air, although
this problem is reduced if the process is contained in a heated
building. The activated sludge process is also susceptible to
upset by shock loadings, although this will be somewhat compen-
sated for with the use of flow equalization and tertiary fil-
tration. A large amount of waste organic sludge is produced,
at least 1000 Ib. dry solids per million gallons treated. The
present operation staffs at both the Vail and Avon plants are
knowledgeable of this process, since it is currently being used
at both locations.
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Pure oxygen can be used in place of air in activated sludge pro-
cesses. This reduces detention time (and thus decreases the
required aeration tank size), allows for increased organic load-
ing, and produces a highly concentrated sludge which is more
easily dewatered, thus requiring less clarifier volume. A very
small amount of aerosol vents from the system, since nearly all
the gas (0^) is used in the reaction. Environmentally this
technique is attractive, but these advantages must be weighed
against the costs associated with production and supply of oxygen
Other Alternatives — Various modifications of the activated
sludge process offer possible alternatives to the conventional
method. The complete mix process provides a uniform organic
load throughout the reactor and is less susceptible to shock
loads, but capital investments and power requirements are gener-
ally greater. With contact stabilization, the adsorption and
oxidation phases are separated, and the tankage requirement is
theoretically reduced. However, this technique is usually only
recommended as a temporary back-up process when extra capacity
is needed in the existing plant. High-rate treatment requires
shorter detention times (less tankage), but produces greater
sludge volumes and is highly susceptible to upsets. Extended
aeration requires considerable additional tankage, although
very little waste sludge is produced. The process is usually
only recommended for very small plants. Other biological pro-
cesses include aerated lagoons, which in cold climate areas re-
quire very large land areas, not physically or economically
available. Trickling filters require more space than activated
sludge systems, are generally less efficient, require primary
clarification, and are more adversely affected by low tempera-
tures .
Ammonia Reduction
Proposed System — Should the proposed un-ionized ammonia stand-
ards be adopted by the state, it will be necessary to provide
ammonia reduction processes at all plant locations. Since
ammonia reduction to 2 mg/1 will be sufficient to meet stand-
ards and the proposed allowable nitrate limitations are rela-
tively unrestrictive, it has been determined that ammonia re-
moval by in-plant biological oxidation (nitrification) to the
nitrate form is the most feasible process to be used. Nitrifi-
cation will be provided with tertiary, packed bed, submerged
filter reactors. The filter media may consist of gravel,
stones, coal or manufactured materials. Liquid flow is normally
upward and oxygen is injected into the influent line or air is
bubbled in from the reactor bottom. An aerobic environment is
maintained to allow oxidation and assimilation by nitrifying
bacteria.
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Evaluation — Biological nitrification is adversely affected by
cold temperature. Ideal operating temperature is 31.5° C, yet
during the winter, sewage temperatures less than 10°C are common,
particularly at the Avon plant. Low temperatures severely retard
the bio-reaction and lessen bacterial yield. To compensate,
systems must be covered in heated buildings and designed for con-
servative hydraulic and organic loading rates. The proposed
method, while a relatively new concept, is probably the nitrifi-
cation technique least susceptible to cold weather effects, since
it is compact and economically enclosed, and allows for bacter-
ial growth on fixed media, which prevents bacteria loss during
cold periods when cell yield is low. Post-clarification is not
needed. The process may require as much as four months time for
start-up. If the oxygen injection method is used, effluent
must be recycled, due to the limited solubility of oxygen. Pro-
perly designed and operated, effluents containing 2 mg/1 ammonia
or less should be attainable under most climate conditions.
Other Alternatives — Nitrification can also be accomplished with
other tertiary processes, including downflow filters, bio-disc
reactors and suspended growth (activated sludge) systems. All
such processes must also be enclosed and kept as warm as possible.
With the suspended growth process, clarification is required and
must be designed with a very low overflow rate, since the bac-
teria are fragile and very difficult to settle. The aeration
system may expose the liquid to cold air temperatures. Thus,
this process, although the most commonly used technique, is
least adaptive to cold climates. Either the downflow filter
method or bio-disc process are feasible alternatives, since both
can be economically covered and require minimal operating power.
The processes are simple and do not require post-clarification,
since the bio-mass is retained on the media. Nitrification can
also be obtained to some degree within the activated sludge
secondary treatment process by extending the reactor detention
time. However, the level of nitrification achieved may fluc-
tuate greatly, depending on organic loading. This rather un-
reliable method is not recommended where highly efficient and con-
sistent ammonia removal is required.
Ammonia can also be removed from sewage with physical/chemical
techniques, all of which can be immediately started up and
shut down. Ion exchange concentrates all ammonia into a brine
which must then be wasted (cannot be discharged). The process
requires a high degree of pretreatment and is very expensive.
Ammonia stripping, while effective in warm climates, will not
function in air temperatures below 0 C, due to the extremely
high solubility of ammonia gas; in addition, lime used to in-
crease the sewage pH level results in a waste chemical sludge,
but phosphates are also removed with this procedure. Break-
point chlorination converts the ammonia to chloramines and
eventually to nitrogen gas, which is easily stripped from solu-
tion; a large amount of chlorine is needed which greatly
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increases the dissolved solids content of the effluent, and
dechlorination is necessary for most receiving streams. (De-
chlorination may also be required following chlorination for
disinfection, although considerably less chlorine would likely
be used.)
Sewage Filtration
Proposed System -- Gravity filtration will follow the nitrifi-
cation process. The filters will be either dual or tri-media
and their purpose will be to further reduce suspended bacteria
remaining in the effluent from the activated sludge and nitri-
fication processes.
Evaluation -- Filtration provides an excellent means for polish-
ing biological secondary or tertiary effluent, since most BOD
(organic material) is in the suspended form at this point and
can be filtered. The use of a filter virtually assures that
excessive BOD and suspended solids will not be discharged from
the treatment plant. The space requirement is minimal which
allows for economical enclosure, which is necessary to prevent
freezing. Operation is simple, but periodic backwashing is
required. A filter-aid chemical is usually needed, and the back-
wash water may increase the treatment plant hydraulic load by
more than ten percent.
Other Alternatives — When it is established that this type of
tertiary polishing is needed, the only alternatives are other
types of filters (upflow, pressure, etc.) or aerobic lagoons,
which, in Colorado, are required by law for small treatment
plants. High rate land application (infiltration/percolation)
also provides good effluent polishing, but requires very large
land areas for construction of percolation beds.
Flow Equalization
Proposed System -- An aerated flow equalization process is pro-
posed for the Avon plant, and, under some alternatives, for the
upstream facilities. The system will be placed ahead of the
activated sludge aeration tanks so that this and all subsequent
processes will have a continuous, non-fluctuating flow.
Evaluation -- Equalization is commonly used in industrial waste
treatment, but usually is not necessary or economically feasible
for domestic sewage plants. However, it can be extremely valuable
in resort areas where plant hydraulic loadings may be highly vari-
able over the course of a typical day- Processes which follow
-------
flow equalization can be designed for lower peak flows, and
process efficiency is increased. Aeration and mixing should be
provided to prevent septicity and to keep all solids in sus-
pension. The process should be enclosed to avoid exposure to
cold air temperature.
Grit removal normally precedes equalization. Since grit re-
moval is not proposed for the Vail facility, it may be more
difficult to prevent settling in the equalization basin, if the
flow equalization process is used. Provision for solids re-
moval may be necessary.
The only alternative to flow equalization is to design the treat-
ment processes to accept the extreme loading variations. Clari-
fiers should be designed for peak flows which could increase
their size considerably. Biological processes designed for high
loadings may not perform efficiently during low loading periods.
Sludge Processing and Disposal
As previously discussed, sludge handling will only be carried
out at the downstream plant site (Avon). Sludge generated at
the upstream facilities will be returned to the interceptor
lines for conveyance to a downstream plant. With the proposed
treatment processes described in this section, the only waste
sludge which will be produced will be secondary activated
sludge. This organic material consists mostly of carbonaeous
bacteria, and is removed from the final clarifiers (following
aeration) at a solids content of normally less than one percent.
Proposed Systems — Sludge will be pumped from the final clari-
fiers directly to aerobic digesters. At Avon, the existing
aeration tanks will be used for aerobic digestion, and aeration
will be provided with submerged turbines. Following digestion,
the sludge will be mechanically dewatered. Use of a centrifuge
is proposed for this operation. The dewatered sludge will be
trucked to a specified site and landfilled, unless more suitable
disposal sites are found, such as use on golf courses, interstate
highway median strips, public greenbelt areas, and private lands.
The aerobic digestion process was developed specifically to
handle waste activated sludge produced from aerobic treatment
plants without primary clarifiers. The operation is simple and
well suited to the high water content and aerobic nature of the
waste. The digested sludge is essentially odorless and has good
drainability- It contains significant levels of nutrients and
thus has agricultural value. The process is, however, adversely
affected by cold temperatures, which retard the biological
reactions and the rate of the reduction of volatiles. This
constraint can be partially overcome by providing increased de-
tention time and enclosing the process in a heated building
Aeration by surface agitation is discouraged because of the"heat
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losses which accompany this method. Even with such measures,
it is likely that digestion efficiency will decrease during
the winter. It is not usually economically feasible to pro-
vide heat to the process, since unlike anaerobic digestion, a
fuel by-product such as methane gas is not produced with the
aerobic process. Separation of liquid from solids by gravity
in the digester is rarely effective without chemical addition,
which could hinder the agricultural value of the sludge.
However, if chemicals are not used, the supernatant return may
contain a considerable amount of sludge.
Sludge dewatering should be provided whenever disposal is by
landfilling. Mechanical dewatering allows this to be accom-
plished with a minimum space requirement. Chemical conditioning
is usually necessary, and digestion, while not required for
land-filling, also renders the sludge more dewaterable. The use
of centrifuges for this purpose is far less common than the use
of vacuum filters, but nonetheless feasible for smaller plants.
The solid bowl scroll centrifuge is the most popular type used,
and can be adjusted to provide for variable cake moisture and
solids capture. Chemical conditioning reduces the amount of
solids returned to the sewage plant in the centrate, but may
render the sludge unsuitable for agricultural purposes. Opera-
ting the unit for maximum cake dryness could produce a dewatered
sludge with a solids content as high as 20 percent.
Alternatives -- Anaerobic digestion, while a commonly used
process, is not well adapted to activated sludges with high
water content. Further, use of this technique would require
completely new facilities since those now in use at the UEVSD
plant are based on the aerobic principle. The process is best
suited and commonly employed where primary clarification is
used, which produces a thicker, less gelatinous sludge. Acti-
vated sludge must either be thickened or mixed with primary
sludge prior to anaerobic digestion. Since activated sludge
will not readily thicken by gravity alone, dissolved air
flotation would probably be necessary- Anaerobic digestion
produces a sludge reduced in volume, volatiles, and odors.
Methane gas is produced as a byproduct, and can be captured
and used as a fuel to heat the digester, which is necessary
since operating temperatures normally should be in the 32.2°
to 35° C range. The process is complex and susceptible to
upset, but less affected by cold temperatures if properly
heated. Anaerobic digestion would be highlv recommended if
primary treatment were to be used at the downstream plant,
since the constant heat supply (from utilizing the methane gas)
would provide for consistent digestion efficiency, regardless
of climate conditions.
Vacuum filtration is tne most common mechanical sludge dewater-
ing method used in the United States. Properly operated, and
with the use of chemical conditioning, nhe process can be
optimized to produce a dry cake and minimize the amount of
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solids returned to the plant in the filtrate. Such high effici-
ency may not be as easily attainable with a centrifuge. Vacuum
filters generally do not perform well with aerobic sludges unless
they are effectively digested or thickened.
Sludge dewatering on sand beds is the simplest technique. How-
ever, large amounts of land are necessary, and pretreatment with
digestion is recommended to reduce odors and sludge volume.
Because of the adverse winter climates, it would be necessary
to either cover the drying beds or provide extensive sludge
holding facilities. Sludge dewatered on sandbeds attains a very
dry state, which significantly reduces sludge volume and subse-
quently the number of truck hauls to the landfill site. In some
locations, sludge beds have been poured during cold weather and
allowed to freeze, which resulted in rapid dewatering when the
sludge thawed. Additional bed capacity would be needed to
implement this concept, since sludge would not be periodically
removed during the winter season.
Most other sludge handling processes are either economically or
environmentally unfeasible. These include incineration, which
has high power requirements and results in discharge of par-
ticulate matter to the air. Reduction of such air pollution
requires considerable additional power and expense. Sludge heat
drying is also expensive since an outside fuel source is needed,
although the dried sludge can sometimes be marketed. Heat con-
ditioning is very complex, produces a dry inert sludge (no
agricultural value) and greatly increases the organic load on
the treatment plant.
Disinfection
By July 1, 1977, in accordance with PL 92-500, certain secondary
treatment standards must be met at sewage treatment facilities.
By this date, the Vail, Avon and Red Cliff treatment works must
reduce fecal coliform count in discharged effluent to less than
12,000/6,000 mg/1 (30 day average), and this limit will also be
imposed upon any new treatment plants in the study area. At the
present time, disinfection requirements are not so restrictive.
Proposed Systems — Chlorination is presently used at the
existing facilities, and it is proposed to continue this prac-
tice at these and all new sites, if possible. However, it may
be found that the required disinfection level cannot be attained
with chlorination without discharging excessive chlorine re-
siduals to the receiving stream. This may be particularly true
at Vail, where the low winter flows of Gore Creek limit its
ability to accept chlorine residuals without the recommended
in-stream chlorine levels being exceeded.
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Where chlorination cannot be used for this reason, alternatives
must be proposed. Those recommended are disinfection with
ozone instead of chlorine, or chlorination to the extent neces-
sary, followed by dechlorination with sulfur dioxide (S02)• In any
event, stream standards must be met.
Evaluation — Chlorination is the most common disinfection
method used in wastewater treatment. Historically, it has
provided good disinfection, attaining required kill levels
within 20 to 30 minutes of contact time with reasonably low
residual discharges. However, it will be difficult to attain
the extremely high kill level required in 1977 and, at the same
time, discharge the very low chlorine residuals necessary to
maintain stream water quality standards. The Colorado River
Water Quality Management Plan assumes that other disinfection
methods will be needed in the mountain areas, since water qual-
ity requirements in cold water bodies are generally more strin-
gent. Cold receiving waters further aggravate chlorination, in
that fecal coliform bacteria tend to survive longer and chlorine
residuals dissipate at a significantly slower rate. It is ex-
pected that the use of chlorination alone in the Vail area will
not be sufficient to meet both kill and chlorine residual
requirements. In treatment works discharging to the Eagle River
chlorination may be found to be adequate, but will require
extended contact periods and efficiently designed contact
chambers.
Ozone (03) appears to be the most feasible alternative for dis-
infection. Ozone is more expensive than chlorine and operations
and maintenance are more complex. However, ozone does not
maintain a long-lasting residual. It is generated on-site,
thus eliminating the need to transport and store hazardous
chemicals. However, a considerable amount of electrical power
is needed, and a standby source must be available for power
failures. Ozone also poses a more difficult industrial health
hazard than chlorine, although both require care in handling
and operation. A much shorter contact period is necessary than
with chlorine to attain the required kill, and ozone also pro-
vides oxidation potential for further reduction of BOD and
odors.
The purpose of dechlorination is to allow chlorine to be applied
in necessary amounts to obtain the required kill, without fear
of discharging excessive residuals to the receiving stream.
Dechlorination with sulfur dioxide gas (S02) removes both free
and combined chlorine residuals from wastewater. SO2 is a
reducing agent, and when added to chlorine and water, produces
hydrochloric and sulfuric acids. Very little contact time is
necessary; the reaction is instantaneous and application of S02
can be made at the end of the chlorine contact chamber and mixed
mechanically. The amount is used directly proportional to the
amount of residual to be removed. The gas must be stored and
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applied under pressure, much the same as chlorine, and the stor-
age temperature is very critical. Accurate and responsive metering
is necessary to insure that sufficient dosages are always
applied. All the chlorine residual will not necessarily be
removed, but this technique appears to be among the more reliable
dechlorination methods.
Other Alternatives — Other disinfection methods include the use
of iodine, bromine-chloride and other halogens, and lime to
raise the pH value. Halogens, primarily used as emergency dis-
infectants in water supply systems, are highly soluble (long
lasting residuals) and very expensive. Raising the pH above
11.5 achieves good disinfection, but the use of lime (although
temperature independent) produces large amounts of chemical
sludge and imposes high capital and operating costs.
Other dechlorination techniques include the use of aeration,
activated carbon adsorption, and other reducing agents such as
sodium bisulfite and sodium thiosulfate powder, which is common-
ly used to dechlorinate samples for bacteriological analysis.
Aeration will remove the more volatile forms of chlorine, but is
insufficient for combined residuals found in sewage such as
mono and di-chloramines. Activated carbon is highly effective
for chlorine and other organic residuals, but the use of pow-
dered carbon is not sufficient, and granular carbon columns
impose high capital and operation costs.
Sewage Effluent Irrigation and Agricultural Sludge
Application During the Summer
Proposed Systems — Although not specifically included with the
proposed treatment schemes, both of these concepts could
eventually be used during the summer growing season. Treated
effluent can be used to irrigate golf courses and parks.
Dewatered digested sludge can be used on highway medians and
area croplands.
Evaluation -- It must be emphasized that the purpose of these
endeavors would not necessarily be additional sewage or sludge
treatment. No in-plant processes would be bypassed while land
application was being carried out. The primary purpose would
be to make use of a resource that otherwise would be wasted,
and to reduce the quantity of potable water demand for irrigation,
since large amounts of potable water are used for this purpose
in the summer. To be sure, nitrogen (in ammonia or other forms)
will be taken up by plant life, but the in-plant nitrification
process must not be shut down even if all effluent were used
in irrigation, since the process could take four months to
restart when the growing season was over.
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Irrigation with effluent is common in Colorado. The degree of
treatment which will be provided at the plants will produce a
quality effluent high in nutrient content and well suited for
irrigation. Since the water will not be potable, separate
pipelines will be required, which will economically prohibit
irrigation of individual lawns. Effluent irrigation should not
affect water rights, since an equally less amount of raw water
will need to be delivered to meet the irrigation demand.
Properly digested sludge, as previously pointed out, is rela-
tively harmless and has a high agricultural value. Sludge pro-
duced at the Avon plant has, in the past, been used for this
purpose, and it is anticipated that in the future there will
continue to be a demand for a significant portion of the pro-
duced sludge during the growing season. Usage of sludge in this
manner will also reduce landfill capacity requirements.
Undigested sludge, or sludge improperly applied, can cause
ground water contamination, as discussed under non-point pollu-
tion in Chapter II. Before any program is seriously undertaken,
a study should be made of the proposed sites as to soil type and
application rates.
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Ill ENVIRONMENTAL IMPACTS
Environmental impacts are the conditions caused, or brought about,
as a result of the proposed action. They may be adverse or bene-
ficial to the project area or the surrounding area. Impacts are
categorized as primary, as the direct result of construction
activity or plant operation, and secondary, as an indirect result
of the proposed action, the impact of population growth associated
with wastewater facilities. Future population, land use and air
quality projections were presented in the existing social environ-
ment since the level of future human activity could be the same
with or without the proposed action.
The impacts chapter is presented under the following headings:
Primary Impacts of the Proposed Action and Impacts of Growth
Associated with Wastewater Facilities.
PRIMARY IMPACTS OF THE
PROPOSED ACTION
The primary level impacts of the proposed sewerage system expan-
sion are categorized into the following: geology and soils,
biological, noise, water quality and streamflow alteration. Some
of these impacts will occur during both the construction and
operation phases.
In this chapter, the discussion of impacts of the various alterna-
tives will be combined whenever a particular effect applies equally
and discussed separately where differences in magnitude or in kind
apply. The major primary impacts of the alternatives have been
summarized and are presented in Table 21,on the following page.
Alternative 5 allows for the beneficial impacts of the proposed
action to be considered, since without it, detrimental impacts
would occur to the aquatic biota, water quality and human health.
(The no funding possibility is discussed in the next chapter on
financial considerations.)
Geology and Soils
The existing treatment plants within the study area are built on
gravel terraces which were deposited by the Gore Creek and the
Eagle River. These terraces are geologically stable, and impacts
from additional construction activities in these areas will be
minor. The construction of a new plant at Dowds Junction on the
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TABLE 21
IHPAITL. SUTt-lAT.Y
Natuit* of the Inpac
•ju.il H-.
Mli '.uii! \ttfj A I let .it 1
,Mti-in.it lvi- I
:*.\, I'Kint .11 l>ivi nut I
UKikxiii-ally stable
oix-a, minimal uijjact .
Will aid in clearing
debris.
Inss ol 'j acrvs ol
prcdisturbed area
weedy species.
Sedimentation of
streams, loss of
aquatic biota (same
as for all altema-
Modc.-r.itc sedimentation
and habitat destruc-
tion at 2 sites during
construction and along
interceptors.
Very detrimental to
aquatic life UUL- to
depletion of Gore
Creek.
I'robobl. • septan l.y 111 i.in
lines brlow Dawris |.lar'
[Ixjj.lrul A\'on in
1077 to 2.S IMHU
am: in 19R=. to 4.7
No impacts, qeoloq-
ically stable area
djravel terrace, out
u> flocxl plain) .
Tt;mporar> dist urbani.-?
o: drainaiK->s.
Loss of 6 acres of
predisturbed area .
14 acres disturbed
along interceptors.
Sewaye purpin>i
head flows.
/V'.->.nann V. a 1
'Jr-, i l.mt al Ixwib
Jixction A.} nil i.;
Sam- as 31
i"1..1 di s turban*. •>
[>oss of aquatu Same as HI (a little
biota durinc low flow. more interceptor lino
replacement) .
Loss ol (• acres of
pro-disturbed area.
bane as c 1
{j. A acres d
alonu inLerceptc
to cKjuaLic Life due
to vast ck?pletj.an in
(tort Creek flow.
of Arrowhead
!>;>dJiii \.'ail 3.')
No intact, stab Jo area. Loss of 1 acre.
f luunti 1 UIPJ '. ic'
prr—disturbed arou
Less disturbance to
streane and loss of
aquatic biota and
terrestrial habitat
with 3a,c. 5evere-
disturbances to both
witn 3b,d.
Not detrimental tc
aquatic life/little
chanye in stream
flow for all sub-
jiturnati vtft, .
Probable sepucitv in
below Vail plant.
uf AjTOWllCai. ' J'.
inti.'i (.T-fjt(.)f r-
."iL'.ij k-nvija \ys_i;p-_d*
r''ulfj now plant iown-
strrari in 19f)j, 2. 'i
mad
''fv- IntcTcnpturs
'-Uii]J'tiJ uipj'acts.
It-nvx 'i ary drama-10
Potuntial loss of
iruvel resources.
Ijocataon uncctLjmuned,
potential subsidence.
•'^urruii_vu_ 4
iri" Vail parucipationj
Lionel A\pon to J.5 mud Same as Above
In 19Q5, ncv [jlant or* Same as Above
expand Avon plant
<^- DC ]panar<].
No impact
-------
terrace between 1-70 and Gore Creek would cause negligible impacts
since considerable alteration has occurred from the fill activities
of the railroad and highway, and from the construction of several
abandoned cabins which exist on this site (Alternatives 1 and 2).
Future construction at a downstream site is not an immediate part
of the proposed project, but is rather a proposed expansion in
capacity to be considered for construction in 1985. The site for
a new downstream facility would potentially conflict with the
development of existing valuable gravel resources and should be
selected with these resources in mind.
Interceptor construction (line replacement) will affect the present
route, thus having little impact on the geology or soils of the
area. Future construction of interceptors to a downstream site
cannot be evaluated until an alignment has been selected. This
would occur in 1985 if the option to build facilities downstream
were selected.
Biological
The overall impact to vegetative communities from any of the pro-
posed alternatives is expected to be minor. If revegetation
programs and reclamation procedures are followed, local vegetative
communities could actually become more diverse and could support
more wildlife.
The riparian and lowland meadow communities are the primary ones
to be affected by the proposed construction activity. Neither
community represents a unique habitat. The areas of disturbance
for these communities, summarized by alternative in Table 24 ,
represent only a small portion of the total area of each community.
Expansion and upgrading of existing plants for all alternatives
will take place in previously and/or recently disturbed areas.
Plant life at these sites is composed primarily of weedy species.
Even the new plant proposed in Alternatives 1 and 2 at Dowds
Junction is on land already stripped of natural vegetative cover.
The quantification of total acres of vegetative disturbance was
calculated from preliminary construction drawings. An average
overall width of disturbance of 15 feet was assumed. These calcu-
lations are utilized partially to indicate the relative impacts,
while total acres disturbed may be larger depending upon equipment
and the amount of care taken to minimize disturbance. Trees are
to be avoided according to the design engineer, due to their
relative scarcity and the length of time for revegetation. In
addition, some of the areas are along predisturbed routes, in
streambeds, in roadbeds and in areas which have little or no vege-
tation.
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All alternatives as shown in Table 26 represent nearly identical
vegetative disturbances, with the exception of 3b, d and 4. In
these alternatives, the construction of a new plant in 1985 would
necessitate the removal of approximately 10 acres of natural
vegetation at the plant site and another 10 acres along a new
interceptor route. (These latter effects will not be decided
until an option is selected just prior to 1985.) The no action
alternative would cause no impacts to terrestrial vegetation.
Due to the close association between wildlife and vegetation, the
effects to wildlife are closely linked to the impacts to vegeta-
tion. The wildlife inhabitants of the riparian and lowland
meadow communities will thus be most affected by construction
activity.
The construction will affect wildlife directly by removing wild-
life habitat and by causing wildlife to flee the areas of increased
noise and activity. Some burrowing animals, unable to flee, may be
destroyed by construction activity. All alternatives will create
a negative impact to prey species hunted by raptors, but the
immediate effect will be minor since a small portion of the total
habitat area will be destroyed.
No big game animals, raptors, or threatened or endangered species
permanently reside in the area of direct impact of any of the
alternatives.
All of the alternatives (1-4) will have a minor impact on terres-
trial wildlife. Alternatives 3b, d and 4 present the most
detrimental impacts due to the removal of up to 20 acres of
riparian and lowland meadow habitat that has been previously
undisturbed (10 acres permanently removed and 10 acres temporarily
removed). Alternative 5 represents the most serious threat of all
the alternatives to the wildlife in the area, due to the potential
outbreak of disease caused by a severe degradation in water
quality.
The aquatic biota (including fish) will be the most affected of
all the biological communities. The impacts will occur during
two distinct phases, construction and operation.
Alternatives 1-4 present significant short-term effects on aquatic
biota during construction. Environmental problems relating to
increased stream suspended sediment loading will pose the greatest
threat to aquatic biota. Adverse effects of high levels of sus-
pended sediment loads on aquatic biota include:
- Clogging and irritation of breathing apparatus of aquatic
organisms
- An increase in the scouring of benthic organisms from the
stream substrate
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- Impaired vision and resultant decreased feeding efficiency
of a number of local species of fish
- A decreased hatch of fish spawn
- A potential increase in re-suspension or dissolution of
sediment-bound pollutants
- A potential decrease in aquatic primary productivity due
to decreased amounts of available light reaching aquatic
plant life
- A potential change in the "normal" temperature of the
stream due to a change in the thermal characteristics
The increase in turbidity will be caused by heavy equipment activ-
ity in and adjacent to the Gore Creek and the Eagle River during
interceptor construction from surface runoff and channelization.
The larger, more mobile aquatic species such as fish and inver-
tebrates will be able to avoid the turbid waters. These species
may move upstream above the construction activity or downstream
where the sediment load has settled or been diluted. This, in
the case where public fishing access is available, and construc-
tion is taking place, will cause temporary loss of a recreation
resource, a temporary but unavoidable impact.
In addition to impacts resulting from increased turbidity, peri-
phyton, benthos and fish communities may be impacted during
construction by a direct loss of habitat due to the operation of
construction equipment within Gore Creek or the Eagle River.
Mobile species, which are able to move to new habitat, will not
be significantly affected by habitat destruction since only a
very small portion of available aquatic habitat will be disturbed.
Immobile inhabitants, such as periphyton or certain benthic
organisms that are unable to avoid highly turbid waters or
physically disturbed areas, will be destroyed. However, the
ability of the benthic and periphytic communities to rapidly re-
populate a disturbed portion of stream, causes the overall impacts
of a temporary loss of a small portion of these communities to
be minute.
Other adverse impacts on the aquatic community could result from
the contamination of the water by grease or oil from construction
equipment. Such material can be directly toxic to aquatic
organisms by poisoning or it may result in suffocation by inter-
fering with breathing apparatus.
Alternatives 1 and 2 involve the construction of over eight miles
of interceptor line and over ten stream crossings between Bighorn
and Dowds Junction, while Alternatives 3 and 4 involve the con-
struction of approximately five miles of interceptor line and
seven actual stream crossings in this area. All of the alterna-
tives present essentially the same potential for increased
suspended sediment loading of Gore Creek and the Eagle River
-110-
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during interceptor line construction, especially when considering
that the construction is staged. The major difference between
the alternatives will result from the construction of new facili-
ties (Alternatives 1, 2, 3b, 3d and 4) and/or extended interceptor
lines below Avon (Alternatives 3b, 3d and 4).
Construction area disturbances required by Alternatives 3b, 3d
and 4 are among the greatest of any of the alternatives proposed
because, in addition to new site construction, approximately ten
miles of new interceptor construction would be required. Any
of these alternatives would be expected to produce greatly
increased sediment loading to the Eagle River.
Alternative 5, no action, would cause no construction related
impacts. However, the adverse impacts on the stream biota caused
by selection of this alternative are judged to be the most
detrimental of any of the alternatives.
As a result of population increases within the study area, particu-
larly the Eagle River Valley, a number of substances which were
not discharged prior to the 1960's into the area's surface waters
currently are, and will continue to be, discharged. As populations
increase, the number and volume of these substances will increase.
In addition, a number of naturally occurring substances are now
being discharged in volumes and concentrations which are much
higher than natural levels. Degradation of water quality within
Gore Creek and the Eagle River are unavoidable adverse impacts
which accompany population increases in the study area; however,
the adverse effects of these pollutants could be the most detri-
mental if no new facilities were built. A discussion of the pro-
jected pollutant loadings of Gore Creek and the Eagle River, with
each of the proposed alternatives, was presented in Chapter III.
The following is a discussion of the effects which these projected
loadings will have on the biota within the area. A summary of
the effects of these constituents, both construction and operation
related, is presented in Table 22, on the following page.
Water Quality and Hydrology
The purpose of this section is to evaluate the alternatives
(including "no action") with regard to their impact on the
receiving streams. It has been stated by the consulting engineer,
and is to be assumed, that the discharged effluent from all treatment
facilities will meet the following criteria:
- BOD and Suspended Solids 10 mg/1 each
- Ammonia 2 mg/1
An evaluation of the ability of the proposed processes to meet
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Table 22
SUMMARY OF OVERALL POTENTIAL ADVERSE EFFECTS OF THE PROPOSED
ALTERNATIVES ON AQUATIC BIOTA, UPPER EAGLE RIVER VALLEY
Constituent Alternate 1 2 3a 3b
Construction Related Effects
Turbidity c c b d
Habitat Destruction c c b d
Oil or Grease Contamin-
nation c c b d
Operation Related Effects
BOD, D.O., SS b b b b
Ammonia b b b b
Loss of Stream Flow d e a a
Chlorine Residual b b b b
3c 3d 4 5
b d d a
b d d a
b d d a
b b b e
b b b e
a a c a
D b b b
NOTES:
a = Not detrimental to aquatic life
b = Little detriment to aquatic life
c = Moderately detrimental to aquatic life
d = Detrimental to aquatic life
e = Severely detrimental to aquatic life
•
BOD = Biochemical Oxygen Demand; DO = Dissolved Oxygen; SS
Sediments
= Assumes proper and adequate dechlorination.
SOURCE: COM
= Suspended
-112-
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these criteria with other engineering considerations, has been
made in Chapter III, including the proposed sludge conveyance
plan. The following analysis addresses the effects of projected
stream loadings on receiving streams and also on the aquatic biota
within the area. A summary of the overall impacts to the biota
during both construction and operation is given in Table 23 on
the following page.
BOD/Suspended Solids (SS) Loading — With all treatment works
designed adequately for cold weather and flow variation, and all
units performing properly, daily BOD and SS discharges will be
below permit limitations, and in-stream BOD and SS concentrations
will not exceed the proposed limits being considered for the new
Colorado Water Quality Standards (1976). Additional solids and
organic loading regulations will be imposed on the downstream
plants due to the discharge of activated sludge from upstream
facilities to the interceptor system. This must be accounted for
in plant design. The data displayed in Table 23 represents the
most adverse loading conditions, e.g., minimum annual 7-day/10-
year low stream flow and no in-stream oxidation of discharged BOD
from upstream points, allowing an accumulation of BOD and SS.
With no improvements provided, by 1995 large amounts of untreated
sewage will be discharged at both plants, as well as other points,
due to the limited flow capacity of the interceptor system. Under
the most adverse conditions, BOD and SS levels in the Eagle River
would reach 60 mg/1, as shown in Table 23. This will cause
stream oxygen depletion, turbidity, solids accumulation, and
build-up of grease and scum on the water surface. Since mountain
streams reaerate rapidly, septic conditions would be unlikely,
and these streams would probably maintain adequate oxygen levels
for the protection of most aquatic life.
Ammonia Loading -- Most secondary treatment plants remove only a
minimal amount of ammonia contained in sewage through biological
uptake. Nitrification has been observed during the summer in
both the Avon and Vail plant, primarily due to the dilute loading
caused by infiltration. Therefore, ammonia removal facilities are
proposed for all existing or new treatment plants. It has been
stated by the consulting engineer that the processes used will be
able to reduce total ammonia content to 2 mg/1, which is assumed
to produce un-ionized in stream ammonia levels of .02 mg/1 or less.
These levels should ensure the protection of aquatic biota, as
discussed earlier.
Table 24, following Table 23, depicts the total ammonia load-
ings which will be discharged to the receiving streams in
1995 with all facilities operating at full capacity. Such
loadings will, in all probability, occur only in the winter
during the peak ski season. These loadings assume total
ammonia background levels of 0.10 mg/1 in both streams. The
-113-
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TABLE 23
BOD/Suspended Solids Loading in 1995
For Minimum 7-day/10-year low flow : Eagle River - 36.7 cfs
Gore Creek - 12.1 cfs
Required In-stream limits : BOD - 5 mg/1
SS - 25 mg/1
Alternate Discharge
No. Point
1 Vail
Dowds
Avon
2 Dowds
Avon
3 Vail4
Avon,.
Avon .
Squaw Ck.
4 Avon
Squaw Ck.
5 Vail*
Avon
Daily
Plant
Flow
(mgd)
1.5
2.6
4.7
4.1
4.7
3.0
5.8
3.5
2.3
3.5
2.3
fv
Discharged
BOD
(Ib./day)
* tl
125
217
392
342
392
250
483
292
192
292
192
31006
6900 6
Discharged
SS
(Ib./day)
125
217
392
342
392
250
483
292
192
292
192
3100 6
6900 6
Resulting Avg .
Stream BOD
(mg/1)
1.9
1.7,
3.7
1.7
3.7J
3.8,
3'73
2'73
3.7
1.5,
2.5
48
60J
Resulting Avg.
Stream SS
(rng/1)
1.9
1.7J
3.1
1.7
3.7J
3.8
3'73
2'73
3.7J
1.5
2.5
48
60J
NOTES:
1 NHPQ, 1975
2 From proposed new Colorado Water Quality Standards (Colorado Department of Health, 1976)
3 Includes accumulation from upstream discharge (excludes N.J. Zinc and Redcliff)
4 Expand Avon, no new Squaw Creek plant(alt. 3a, 3c)
5 Build new Squaw Creek plant (alt. 3b, 3d)
6 Based on discharge of raw sewage in excess of current plant capacity, BOD and SS of 250 mg/1
7 Total flow - may be in excess of plant or interceptor capacity
SOURCE: COM Inc., Colo. Dept. of Health (1975), NHPQ (1975)
-------
ijl
I
TABLE 2 4
Maximum Ammonia Loading in 1995
During Peak Ski Season
Alternate Discharge
Number Point
Plant
Flow
(mgd)
Total NH0 „
j ~~ M
Discharged
(Ib/day)
Wasteload
Allocation
(Ib/day) 2
(with ammonia (without
removal) ammonia removal)5
1 Vail
Dowds
Avon
2 Dowds
Avon
3 Vail
Avon**
Avon^
Squaw Ck.^
4 Avon
Squaw Ck.
5 Vail
Avon
1.5
2.6
4.7
4.1
4.7
3.0
5.8
3.5
2.3
3.5
2.3
3.0
5.8
25
43
1217
68
1467
50
97
58
977
58
977
_
-
106
229
6457
7787
212
517
309
5177
309
37510
725^0
62
245
245
62
245
245
245
62
245
Average
Resulting
Total NH
1 ? t i-, \ J—N
» (.mg/ J./
Total Stream Ammonia
Stream Allowed
to Maintain
Cone. Un-ionized Cone. Less f
3, 11 Than 0.
(with ammonia (without
removal) ammonia removal)
0.33
0.58
0.70
0.67
0.46
0.46
0.46
_
_
1.40
3.09
3.73
2.84
2.45
2.45
2.45
5.0
3.5
02 mg/l (mg/l)
(winter)
0.93
1.27
1.27
0.93
1.27
1.27
1.27
0.93
1.27
Eagle R. - 38.8 cfs;
NOTES:
1 For 7-day/10-year winter low flows for which minimum ammonia allocation exists:
Gore Ck. - 13.9 cfs (NHPQ, 1975)
2 From NHPQ, 1975 and current UEVSD discharge permit (based on 0.02 mg/l max. un-ionized)
3 Values do not include any background ammonia present
4 At historical pH and temperature (NHPQ, 1975) (Willingham, 1976)
5 Based on ammonia measurements made at the existing plants (M & I Inc., 1976)
6 Based on winter 7-day/10 year low flows and historic pH and temperature (NHPQ, 1975) (Willingham,
7 Includes accumulation from upstream discharge at Avon or Dowds
8 Expand Avon, no new Squaw Creek plant (alt. 3a, 3c)
9 Build new Squaw Creek plant (alt. 3b, 3d)
10 Based on discharge of 15 mg/l total ammonia from total flow - new and treated
11 Values do not inclu'la ary background rtmmorla present
I1.' Value for Vail assume a Dec.-Julv -?1 locaf'o^ of 62 Ib/d ty (net ii> present permit), ha^ed on NHPQ (1975)
SOURCE: CUM Inc., M & T lur:. , HiU'Q 0.97*;), Hi 11; n^hain
1976)
-------
total ammonia levels which can exist during the winter in both
streams before 0.02 mg/1 is reached are given for comparison with
the maximum in-stream levels, which will result from full capacity
plant operation. Also included in the table are ammonia loadings
which would occur if ammonia removal processes were not included
with the alternatives. These values are based on past ammonia
effluent measurements made at the existing plants, and thus are
approximate.
Toxicity of ammonia increases with higher temperatures, thus the
critical loading period in many situations is in the summer.
Established wasteload allocations are often considerably less
in summer, as is the case for the Eagle River and Gore Creek.
However, sewage loadings (not including infiltration) are also
less during the summer in the resort areas. From examining
previous records of water use, sewage maximum and minimum flows,
and community retail sales, it can be estimated that the peak
summer population in Vail occurs in August and that total occu-
pancy (and thus sewage flow excluding infiltration) is approxi-
mately 60 percent of the normal winter season level. Assuming
this trend will continue, Table 25. on the following page, displays
the ammonia discharges resulting from each alternative with all
facilities operating at 60 percent capacity, with or without
ammonia removal facilities included. These values are compared to
the established wasteload allocations and acceptable in-stream
concentrations (based on the same EPA criteria) for the month
of August.
From examining the tables, it can be shown that for all alterna-
tives except no action, the proposed ammonia wasteload allocations
and maximum stream concentrations will not be exceeded during
the winter ski season or during the peak summer period, given
that all facilities provide for reduction of ammonia to 2 mg/1
or less. Less efficient ammonia removal could be allowed at
certain times without these recommended levels being surpassed.
The data does not account for the following:
- Ammonia discharge or seepage from the New Jersey Zinc Corp.
tailings ponds can by itself cause un-ionized ammonia
concentrations above 0.02 mg/1 to occur in the Eagle River.
Sufficient allowance for this ammonia was not made when the
present ammonia limitations were established in the Colorado
River Basin Plan and subseauent studies, and this ammonia,
in combination with the ammonia which will be discharged at
Avon in 1995, may create excessive levels in the river.
- Colorado has not yet established an ammonia standard,
although the 0.02 mg/1 un-ionized limit is included in the
proposed new Colorado Water Quality Standards. if in-situ
toxicity testing determines that this level is either too
high or too low, changes in the restrictions could be invoked.
-116-
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TABLE 25
Ammonia Loading
During August at 60 Percent Operation
Alternate Discharge Daily Total NH Wasteload
No. Point Plant Discharged Allocation
Flow (Ib/day) (Ib/day)
(with ammonia (without ammonia
removal) removal) 3
1 Vail
Dowds
Avon
2 Dowds
Avon
3 Vail?
Avong
Avon
8
Squaw Ck.
4 Avon
Squaw Ck.
5 Vail
Avon
.9
1.6
2.8
2.5
2.8
1.8
3.5
2.1
1.4
2.1
1.4
1.8
3.5
15
26,
736
41,
h
88b
30
58
350
Q
58*
35Q
589
-
64
139,
3896
218,
K
469b
127
309
187.
Q
309
187
309
225
435
36
109
109
36
109
109
109
36
109
Resulting Stream Total Stream Ammonia
Total NH Cone. Allowed to Maintain ,
(mg/1) Un-ionized Cone. Less
(with ammonia (without ammonia Than 0.02 mg/1, (irg/1)
removal) removal) (August)
0.15 0.64
0.24 1.28
0.29 1.55
0.30 1.27
0.19 1.01
0.19 1.01
0.19 1.01
2.25}°
1.4510
0.46
0.46
0.46
0.46
0.46
0.46
0.46
0.46
0.46
NOTES:
1 For 7-day/10-yr low flows (Eagle R. - 56.3 cfs, Gore Ck. - 18.7 cfs) (NHPQ, 1975)
2 Not including infiltration, flows are 60% of max. design flows
3 Derived from ammonia measurements made at existing plants (M & I, Inc., 1976)
4 From NHPQ, 1975 (based on 0.02 mg/1 max. un-ionized) allocations for August only
5 Does not include background ammonia
6 Derived from historical pH and temperature (NHPQ, 1975) (Willingham, 1976)
7 Expand Avon, no new treatment plant (alt. 3a, 3c)
8 Build new Squaw Creek plant (alt. 3b, 3d)
9 Includes accumulation from upstream discharge
10 Derived from discharge of 15 mg/1 total ammonia from total flow - raw and treated
SOURCE: COM Trc., M <\ I, Lie., NHPQ (1975;, V-J Lir^ham (1976;
-------
With no treatment improvements (Alternative 5), ammonia in concen-
trations of at least 15 mg/1 will be discharged with both treated
and raw sevage. During the winter, un-ionized ammonia levels
could exceed .08 mg/1 (including New Jersey Zinc), and will be
greater than .12 mg/1 in Gore Creek, a level which would most
certainly have detrimental, and probably toxic, effects on
aquatic life.
Chlorine Residual Discharge — Chlorination of sewage for dis-
infection results in the reaction of chlorine with certain waste-
water constituents to form combined chlorine residuals. The most
common of these are Cyanogen Chloride (CNC1) and the chloramines
(NH_C1, NHCl.). All are toxic to fish. Although some residuals,
under certain circumstances (pH, temperature, etc.), are present
in greater amounts or are more toxic than others, all residuals
can be considered as one total amount at a given concentration.
The proposed Colorado Water Quality Standards recommend a max-
imum concentration of total chlorine residual of .003 mg/1 in
waters designated to support cold water aquatic life.
Table 26, on the following page, denotes the maximum chlorine
residual discharges that would be allowed from each plant for each
alternative in 1985 and in 1995, at extreme low flow conditions to
insure that the proposed .003 mg/1 limit is not exceeded. These
values cannot account for the following considerations:
- Combined residuals could remain in solution for extended
periods. Since the residual discharged by an upstream plant
could partially be present as the stream flow was. passing
a downstream plant, the downstream facility could be re-
quired to further reduce the level of its residual discharge.
- The data assumes that complete mixing will occur in the
stream, allowing for an even dispersion of the residual,
which is not likely to occur; concentrations will vary
throughout the stream. Because fish are capable of avoiding
areas of excessive residual content, they may not be adversely
affected, even with average residual levels above .003 mg/1.
The Colorado River Water Quality Management Plan states that, for
the anticipated growth, the Vail and Upper Eagle Districts will
both require either an alternative method of disinfection for
wastewater or a dechlorination step in the treatment scheme prior
to effluent discharge. The 303 (e) management plan suggests
disinfection by ozonation as an alternative method, which could
be the final selection for a disinfection process in order to
meet permit stipulations.
If no action were taken (Alternative 5), the Chlorination facilities
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TABLE 26
1985 and 1995 Chlorine Residual Discharge Limitations for Extreme Low
Alternate Discharge
No. Point
1 Vail
Dowds
Avon
2 Dowds
Avon
3 Vail
2
Avon
T
Avon
Squaw Ck. 3
4 Avon
Squaw Ck.
Flow Conditions
Min.
Stream
flow
(cfs)1
12.1
36.7
36.7
36.7
36.7
12.1
36.7
36.7
36.7
36.7
36.7
to Maintain
1985
Plant Max.
Ave. Flow
(mgd)
1.5
2.2
2.5
3.7
2.5
2.7
3.5
3.5
3.5
-
.003 mg/1 Total Residual
1985 Max. Allowed
Cl Residual
Discharged
(mg/1)
0.016
0.032
0.028
0.019
0.028
0.0087
0.020
0.020
-
0.020
-
in Stream
1995
Plant Max.
Ave. Flow
(mgd)
1.5
2.6
A. 7
A.I
A. 7
3.0
5.8
3.5
2.3
3.5
2.3
1995 Max. Allowed
Cl Residual
Discharged
(mg/1)
0.016
0.027
0.015
0.017
0.015
0.0078
0.012
0.020
0.031
0.020
0.031
NOTES:
1 Minimum 7-day/10-year low flow (lowest month) (NHPQ, 1975)
2 No new plant at Squaw Ck.
3 Build new plant at Squaw Ck.
SOURCE: COM Inc., NHPQ (1975)
-------
at the Vail and Avon plants would probably not be capable of
meeting the stipulations required in their discharge permits.
Adequate disinfection would not be possible without excessive
chlorine discharge, and much of the sewage flow will probably not
receive any treatment.
Streamflow Alteration — The wastewater system improvements pre-
scribed by the siting alternatives will affect the present flows
in Gore Creek and the Eagle River. As more stream water is
diverted for municipal use, the required new or expanded sewage
works and interceptors may change the historical return points
for this water or the amounts returned at those points. This, in
turn, will increase or decrease present flows in certain reaches
of these streams.
Projected changes in streamflows predicted for the five site alter-
natives are based on maximum average daily plant discharges and
reflect the difference in conditions as they are at present and
as they will be by 1995 with all proposed improvements completed
and operating. These streamflow alterations are summarized in
Table 27 on the following page.
In Alternative 1, much of Vail sewage would be routed to the Dowds
Junction plant; Gore Creek would be depleted by as much as 2.48
cfs at its confluence with the Eagle River. The discharge at this
new plant would increase flow in the Eagle River by 1.44 cfs
between Dowds Junction and Avon. Below Avon, flows would not
change.
In Alternative 2, abandoning the Vail plant and routing all flow
downstream for treatment will cause a considerable depletion
(4.81 cfs) in Gore Creek. Below the new Dowds Junction plant,
stream flows will be as in Alternative 1.
As can be seen in the table, implementation of Alternative 3 would
have an almost insignificant impact on the flow of Gore Creek or
the Eagle River as far as Avon. However, if a new downstream plant
is built near Squaw Creek instead of expansion of the Avon plant,
flows will be reduced by as much as 3.57 cfs from the Arrowhead
area to Squaw Creek, and greater depletions could occur upstream
of Squaw Creek if this area is developed and municipal water with-
drawn.
In Alternative 4. Vail will treat and release all sewage flows
tributary to the Vail plant with the exception of those generated
in Bighorn. This will cause a minimal amount of depletion in
Gore Creek and the Eagle River as far as Avon. Below Avon
however, flow reductions will be somewhat higher, as great'as 3.57
cfs below Arrowhead with planned development.
Since Alternative 5 calls for no action, the existing lines will
be used to their full capacity. The quality consequences on the
-120-
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I
I-1
to
TABLE 2 7
Streamflow Alteration in 1995
Average Daily Flow - cfs
Gore Ck. Gore Ck. Eagle R. Eagle R. Eagle R.
Alternate Below At Mouth Below Below Below
No. Vail Trat. Dowds Jet. Avon Tmt. Arrowhead
Plant Tmt. Plant Plant
1 -1.86 -2.48 +1.44 0 0
2 -4.19 -4.81 +1.44 0 0
3 +0.47 -0.16 -0.26 O2 O2
-2.023 -3.573
4 -0.47 -1.01 -1.19 -2.02 -3.57
54 +0.03 -0.59 -0.70 0 0
Eagle R.
Below
Squaw Ck.
0
0
O2
o3
0
0
NOTES:
1 Numbers proceeded by "+" are streamflow increases
Numbers proceeded by "-" are streamflow depletions
"0" indicates no change from present conditions
2 No new plant constructed at Squaw Ck. (alt. 3a, 3c)
3 New Squaw Ck. plant constructed (alt. 3b, 3d)
4 Based on capacities of existing interceptors and raw sewage overflow in some locations
SOURCE: COM Inc.
-------
streams would far outweigh the quantity effects, which are proba-
bly nominal.
Further depletion of Gore Creek by 2.48 cfs, 4.81 cfs or 1.01 cfs
as projected for Alternatives 1, 2 and 4, respectively, during
this critical low flow period, may cause extremely low flows in
Gore Creek which may create overcrowding conditions for fish.
Physiological stress due to crowding has been shown to be detri-
mental to trout species. Other potentially detrimental effects
of crowding to aquatic organisms include decreased oxygen content
and a general degradation of water quality. Because 7-day/10-year
low flows in the Eagle River are substantially higher than those
for Gore Creek, alternatives causing Eagle River depletions would
not create these crowding and/or water quality problems.
As population growth continues within the study area, addition
water supplies may be diverted directly from the stream, and
regardless of the sewage treatment alternative chosen, this addi-
tional water need could result in significant stream depletion.
The assessment of this potential impact is presently not within
the scope of this environmental statement because of the many
options which may exist, but have not been fully evaluated, for
providing adequate water supply without significant stream deple-
tion. In some cases, addition water supply systems and storage
may provide for adequate domestic water needs and still preserve
stream flows and values. Conservation of water use is also a
strong alternative to significant depletion of stream flows.
Sludge Conveyance/Sewage Pumping_
The following impacts, sludge conveyance and sewage pumping,
relate more to the engineering analysis of the alternatives than
the biological water quality analyses. Each addresses a specific
engineering problem.
Sludge Conveyance — In each of the alternatives, except numbers
4 and 5, routing of waste activated sludge from upstream treatment
plants (Vail, Dowds Junction) to downstream facilities (Avon,
Squaw Creek) for processing and disposal is proposed. The sludge
will be removed directly from the final clarifiers (at about 5.0
percent solids) and discharged into the interceptor sewer system
which, depending on the alternative selected, may also be carrying
raw sewage from upstream areas. The sludge will mix with the raw
sewage and go through the complete sewage treatment process at a
downstream facility. The purpose is to eliminate sludge disposal
in the Gore Creek and Upper Eagle River area, where it has been a
problem in the past, and to process all sludge in a downstream
location where disposal sites or agricultural demand for the
material will be more available.
Mixing activated sludge, consisting of carbonaceous bacteria with
raw organic matter causes aerobic biological assimilation and
oxidation reactions to occur, provided that free oxygen is avail-
able. It can be assumed that these reactions will occur when
-122-
-------
sludge is discharged to the interceptors carrying raw sewage.
Since the free oxygen level in sewage and sludge is low, it could
be depleted, causing septic conditions to occur in the interceptors,
This circumstance will only be avoided if sufficient reaeration
takes place within the interceptor.
The relatively steep grades of the sewers should provide better
than normal reaeration potential. The depletion of oxygen in a
sewer atmosphere is normally insignificant; however, the access
to and availability of sufficient air (oxygen) may be limited by
the use of water-tight manholes and by lack of space when the
sewers are nearly full. The cold sewage temperatures encountered
in the winter will retard the biological reactions greatly,
thereby lessening the oxygen consumption. However, for some
alternatives, it seems fairly certain that septic conditions will
be created, even during the winter since organic loading is
greatest during this time.
Septicity in long sewer lines is not uncommon. Anaerobic condi-
tions are present to some extent in most sanitary sewers, but when
a sewer becomes highly septic, the following characteristics must
be considered:
- Sulfates in the wastewater may be reduced to sulfide
gasses, which are highly odorous at lower concentrations,
and toxic at higher ones.
- The sulfides in septic sewage are corrosive to some metals,
and can attack concrete pipes.
- During activated sludge treatment, sulfides in the sewage
may encourage the formation of filamentous sludges, which
are difficult to settle.
-.Highly anaerobic sewage may require increased aeration
capability at the treatment plant.
Among the proposed site alternatives, the interceptor areas most
likely to experience septicity due to injection of waste acti-
vated sludge into the lines are:
Alternatives 1 and 2: Directly below the Dowds Junction
Treatment Plant.
Alternative 3: Directly below the Vail Treatment
Plant.
In all cases, the mixture will become more diluted as flows pro-
ceed downstream. Anaerobic conditions in sewers are common, and
septic sewage causes no critical problems in treatment, although
some odors may be present and extra aeration may be needed.
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Sewage Pumping -- Pumping of raw sewage is usually avoided, due
to power costs and the abrasive effect on pump mechanisms.
Currently, wastewater collected in the Arrowhead subdivision is
pumped back to the Avon treatment plant. With Alternatives 1,
2 and 3a,c, all future Arrowhead flows will need to be pumped
back to Avon (unless a downstream plant were builL as part of a
separate project). If a downstream plant were built in 1985,
sewage from Arrowhead would be pumped back to Avon only until
1985 (Alternatives 3b,d and 4).
Noise
In recent years, the effects of noise on the wildlife within a
developing area and upon human inhabitants have received more
intensive study. Although an exact definition of what constitutes
noise has not been determined, it has come to mean "unwanted sound.'
Noise classifications, termed "levels of annoyance" are somewhat
arbitrary since they vary with specie and individual. Table 28,
on the following page, gives the various noise levels for people
which will cause effects such as hearing impairment, sleep inter-
ference, annoyance and physiological stress. To establish the
effect of noise from any source, total noise levels must be con-
sidered. Construction projects are normally composed of five
steps each with noise characteristics caused by the mixture of
equipment. These five phases with their typical ranges of noise
levels are given in Table 29, following Table 28. These levels
take ambient noise in suburban/urban areas into account. In Vail
ambient levels would probably be closer to suburban, except in
the vicinity of 1-70. The location of future proposed facilities
on river terraces and along the valley floors will not necessitate
the removal of bedrock or any blasting activity. Individual equip-
ment noise during construction will range from 70-100 decibels.
However, composite noise pollution levels may reach levels between
100-108 decibels with average levels of between 84 and 89 decibels.
These levels, while typical of public works construction sites,
will cause annoyance and possible hearing impairment if continued
over extended periods of time.
The impact from noise during treatment plant operation is expected
to be minor, since the facilities will be enclosed, and exterior
noise levels will be very low.
Archaeology, Paleontology and Historic Sites
Since each alternative recommends construction in areas which
have been excavated or disturbed in the past, no potential impacts
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TABLE 2 8
NOISE LEVELS AND THEIR VARIOUS EFFECTS ON PEOPLE
EFFECTS
Hearing Impairment
Speech Interference
Sleep Interference
Annoyance
Task Interference
Moderate Level^-
of Risk
(dBA)
70
45
40
40
55
Appreciable Level
of Risk
(dBA)
90
60
70
60
75
2
Physiological Stress
NOTES:
1 Probability that the effect will occur
2 Affected by quality, frequency, indivdual sensitivity, time of
day and nature of the exposure.
SOURCE: U.S. EPA. 1971. Noise from Construction Equipment and
Operations, Building Equipment and Home Appliances.
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TABLE 29
TYPICAL RANGES OF__NOISE. .LEVELS_ AT^.CONSTRUCTION SITES
Phase of Construction
Ground Clearing
Excavation
Foundations
Erection
Finishing
NOTES:
1
Suburban 1
Residential"
II1
Urban"
II'
84
8
103
88
7
106
88
8
108
79
9
103
84
7
101
84
8
104
78
3
86
88
8
108
78
11
108
84
8
104
84
6
100
89
6
105
88
8
108
79
3
88
84
6
100
84
7
101
79
2
85
88
8
108
79
4
88
84
6
100
Ave. noise (dBA)
Std. deviation
Noise pollution
level
Ave. noise (dBA)
Std. deviation
Noise pollution
level
Ave. noise (dEA)
Std. deviation
Noise pollution
level
Ave. noise (dBA)
Std. deviation
Noise pollution
level
Ave. noise (dBA)
Std. deviation
Noise pollution
level
Suburban residential area's typical ambient noise level of
50 dBA
2
Urban area's typical ambient noise level of 70 dBA
I - All pertinent equipment present at site
II - Minimum required equipment present at site
SOURCE: U.S. Environmental Protection Agency. 1971. Noise
from construction equipment and operations, building equipment
and home appliances.
-126-
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are expected to artifacts or finds. If artifacts were to be
uncovered, even in a pre-disturbed area, a negative impact
would not be likely, however adequate mitigation measures would
then be required to ensure that nothing of archaeologic value is
destroyed.
Future improvements associated with Alternatives 3b,3d and 4
involve pipeline excavation and building of facilities in areas
of previously undisturbed soils. Disturbance of ground along a
river in an alluvial valley represents a potential negative impact
since the general area is likely to have contained either a camping
site or a settlement for the various Indian tribes which inhabited
the area. Executive Order 11593 and Section 106 of the National
Historic Preservation Act would apply. Selection of future improve-
ments is not anticipated before 1982-1983.
IMPACTS OF GROWTH ASSOCIATED WITH
WASTEWATER FACILITIES
It is estimated that during the period between 1975 and 1995 the
permanent population of the study area will more than double with
the average daily population up by approximately 250 percent. The
Avon/Beaver Creek and Arrowhead development areas are projected,
under this 201 study, to accomodate nearly 80 percent of this 20
year growth projection. In contrast, permanent population within
the Vail/Gore Valley area is projected to increase only about 20
percent with average daily population increasing by around 35
percent by 1995.
From a land development perspective, conversion of land from its
present undeveloped state or semi-developed state (grazing, etc.)
to commercial, residential or public use will occur to the greatest
extent in the Beaver Creek, Avon and Arrowhead areas. These dev-
elopment areas encompass in total approximately 3500 acres, most of
which has not been developed (see Figure 12). In the Gore Valley,
less than 400 acres are projected to be developed within the next
20 years, with much of this future development in filling between
presently developed areas.
Clearly, the nature and extent of secondary impacts associated
with the projected population growth and land development within
the study area are largely tied to the expected development of the
Beaver Creek and Arrowhead ski areas and the adjacent Benchmark
and Eagle-Vail areas. These secondary impacts were evaluated in
the Forest Service's Final Environmental Statement for Meadow
Mountain and their Environmental Analysis Report for Beaver Creek
Recreation Area. In these environmental studies, the Forest
Service recognized that, "The secondary effect related to the
development of a winter sports area are considerably more signif-
icant and controversial in comparison to the effects of the
remainder of the proposed action." For that reason, the Meadow
Mountain Final Environmental Statement contained an evaluation of
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the principal secondary and direct impacts within fifteen major
areas of concern. Their findings from both studies are summarized
in Table 30 on the following pages. Since completion of the Meadow
Mountain Statement and the Environmental Analysis Report, the Forest
Service, with agreement from the State of Colorado, has issued a per-
mit for use of federal lands in developing the Beaver Creek ski area.
Also, many of the necessary approvals for development of Beaver Creek,
Benchmark, Eagle-Vail and Arrowhead have been given by Eagle County.
Since the secondary impacts of the projected growth has already
undergone an extensive evaluation and governmental approvals have
been given, secondary impacts are not treated here in depth. If
more information on secondary impacts than contained in Table 30
and other portions of this Statement on air quality, urban runoff
pollution, etc., is needed by the reader, he or she is referred to
the U.S. Forest Service Final Environmental Statement for the
Meadow Mountain Planning Unit and the Environmental Analysis Report,
Beaver Creek Winter Sports Site and Year Around Recreation Area.
Relationship Between Treatment Works Planning
and New Development
The preferred alternative provides for upgrading of the Vail plant
and expansion and upgrading of the Avon facility. Because these
plants are interconnected, with the latter accepting flows beyond
Vail's capacity, treatment plant location (insofar as the area from
Bighorn to Avon is concerned) does not exercise an overriding con-
straint on developmental patterns. Stated another way, within the
projected population, the treatment plant geometry can absorb devel-
opment almost wherever in the service boundaries it chooses to go.
This flexibility is not intentional, rather, it develops from
technical and cost-benefit considerations in plant design and
operation.
The location of sewage interceptor lines is, from an environmental
and engineering point of view, set by preference for (1) gravity
flows to minimize costs, (2) use of previously-disturbed sites for
environmental reasons, and (3) cost-savings by use of current plant-
sites and facilities. Further, the nature of the topography (mountain
valleys) influences the location of development and requires that the
sewage lines run at, or close to, the valley bottoms. Thus, inter-
ceptor location, as such, considering the preference for retaining
the Vail and Avon plants, will have only a marginal impact on devel-
opment patterns.
Interceptor size, on the other hand, can exert a direct impact
on development patterns since line segment capacities are directly
related to sewered population. However, in the study area, this
potential constraint is reduced in effectiveness by the fact that:
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TABLE 30
SUMMARY OF IMPACTS AS PRESENTED IN THE FINAL ENVIRONMENT STATEMENT
FOR THL MEADOW MOUNTAIN PLANNING UNIT AND THE
ENVIRONMENTAL ANALYSIS REPORT FOR BEAVER CREEK RECREATION AREA
Availability of
Employment
Opportunity
Supply of
Permanent
Housing
Provision of
Urban Services
Solid Waste
Management
Required School
Facilities
Energy
Conservation
Air Quality
Probable Effects
Generally beneficial; however, if the New Jersey Mine
closes, a certain proportion of the miners will prob-
ably not be able to make the adjustment, and will,
therefore, be considered unemployable in the recreatior
industry.
It appears that the county and developers have beer.
able to develop reasonable plans to supply employe..
housing. The arrangement does not insure that the
cost of employee housing will remain reasonable.
Demand for urban services will increase. There shouxd
be concern that the overall delivery of urban services
will be fragmented, resulting in greater costs to
residents and in levels of service which will var^
substantially.
It is estimated that a doubling of the present volume
of solid waste will occur within the Upper Eagle
Valley. Action has been taken by Eagle County to
expand the present sanitary landfill at Wolcott and
to study long range solutions for solid waste disposi.1.
The development will provide a favorable impact in the
school district, financially, at full development.
However, there will probably be a deficit period M
the early years unless advanced payments are mad*
by developers as credit against future taxes.
The formation of a recreation and support community
in the Avon Valley will cause increased demands to
be made on the production and distribution of energy.
Power requirements will result in further air qualitv
reduction at Hayden and Craig, Colorado where coal
fired generating facilities are located to serve the
Avon region.
If the Vail experience is to be of any value, local
concern should be concentrated on the potential pollu-
tion caused by wood-burning fireplaces. Although
calculations show that air quality in the Beaver Cre<_k
Valley should be maintained within State standards,
some air quality degradation is unavoidable. In orJer
to reduce air pollution, the Beaver Creek Recreation
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Table 30 (continued)
Topic
Air Quality
(continued)
Water Supply
Requirement
Water Quality
And Urban
Runoff
Probable Effects
Area land use plan includes: (1) a mass trans-
portation system designed to serve the major
concentrations of density; (2) Parking facilities
at the entrance to the property,limiting most traffic
to the base of the valley; (3) initially, the maximum
allowable number of fireplaces constructed in Beaver
Creek shall be limited to 1000 and this limit will be
reviewed and adjusted annually based on air quality
data and analysis; and (4) a fireplace control plan
for restriction of fireplace operation during adverse
meteorological conditions.
It would appear that domestic water requirements will
exceed the availability of water from Beaver Creek.
In order to preserve the fisheries characteristics
of Beaver Creek, the domestic water diversion point
will be located near the mouth of Beaver Creek where
it enters the Eagle River.
Increases in late summer flows from tree removal should
not be a significant factor in flooding hazard or
channel damage as long as the integrity of the natural
waterways is maintained. An increase in rate and volume
of surface runoff will be caused by replacing pervious
surfaces with impervious surfaces. Detention ponds
will be installed as appropriate to hold up turbid
water long enough to permit removal of suspended solids.
Water Quality
and Sewage
Treatment
Soil Erosion
Reduction in
Scenic Values
All projected increases in sewage will be accomodated
by the proposed expansion in treatment facilities.
Some increase in stream turbidity will be unavoidable
during construction of roads, ski trails and buildings
which require ground cover disturbance. However,
these effects can be minimized by implementing: (1)
practices which minimize ground cover disturbance;
(2) installation of detention ponds, filters and
sediment traps; and (3) prompt revegetation of exposed
soil. A riparian buffer zone is also planned to
mitigate potential adverse water quality impacts.
In terms of national importance viewing duration and
high use volume, the Eagle River Valley bottom is
the most sensitive area of scenic quality. Private
land developments planned, approved and in some
cases under construction, will be the most significant
factor affecting visual quality.
-130-
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Topic
Wilderness
Suitability
Wildlife
Loss
Lowering the
Quality of
Life
Table 30 (continued)
Probable Effects
The loss of apparent wilderness suitability on 1,650
acres to be removed from the roadless area and
managed for other than back-country values can be
considered irreversible. Also, creation of a new
population center in lower Beaver Creek might place
more user pressure on the adjacent Holy Cross road-
less area.
Development, related human activity and harassment
of deer and elk by free-roaming dogs could result
in loss of migration routes and some winter habitat,
causing eventual reduction or emigration of herd?.
However, creation of an "elk enclave" and subsequent
habitat improvement activities could result in inr^r ov
winter conditions for those animals that migrate Lo
the foothills east of Beaver Creek.
Assuming that the existing character of the Avon
area is something worthwhile, the potential adverse
effects are typically associated with the change
from a somewhat rural character to a more urban-
type setting. This is manifested by such conditions
as increased population, congestion, additional
government control, increased cost of living, and
changes in both living habits and employment
opportunities.
SOURCE: U.S. Forest Service, White National Forest, Final Environu.e.i'-
Statemen Statement for the Meadow Mountain Planning Unit and EnvironiTem.al
Analysis Report for Beaver Creek Winter Sports Site and Yoa..-
Around Recreation Area
131-
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- The lines must be sized to accommodate the peak
population (winter), thus providing available
capacity for other times of the year
- The line between Vail and Avon must be able to
handle Vail raw sewage bypasses and activated
sludge and, therefore, would probably be designed
with a significant safety factor.
The UEVSD consulting engineers have recommended that a predesign
review of interceptor line sizing in relation to specific future
contributory areas be conducted.
Thus, in summary, the configuration of the prepared plan system
permits a range of development. In fact, the local topography and
land ownership patterns are, probably, significantly greater con-
straints than is the treatment works system.
Wastewater System Construction Staging
Population and land use projections for the study area have been
based upon the successful development of the Beaver Creek ski area.
They provide little allowance for fringe development and a consider-
able deceleration in the present growth rate in Vail. The population
projections are, of course, subject to a range of error and, as
indicated earlier in this report, there can be honest differences in
views as to how much and where. The study area's economy is volatile,
resting as it does on seasonal recreation. Thus, changes in public
tastes and/or the absence of the proper climatic conditions could
significantly affect the rate of future development. This, then,
leads to a consideration of staging the construction of treatment
works required to support growth. The question then arises as to
the impacts of staging on facility costs, local planning efforts,
and land use.
- The preferred alternative provides for meeting 1985 waste-
water treatment works needs immediately and for constructing,
in the 1985 time period, additional capacity to meet pro-
jected 1995 needs. The treatment capacity for 1995 needs
would be constricted either at Avon, or at another site
not yet selected. By utilizing, to a maximum, current
facilities and minimizing land disruption, the first stage
(or immediate) construction program is the most economically
and environmentally sound.
- By waiting until the early/mid-1980's to determine the
need for 1995 populations, actual out-of-pocket capital
costs may not be lessened, but the potential for avoiding
excess capacities and for continued coorindation of waste-
water and other functional planning is significantly
increased.
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- Also, by restricting major development to the Vail-Arrowhead
corridor over the period of the first stage, the potential
for orderly development is enhanced.
AIR QUALITY
IMPACTS
In order to calculate pollutant concentrations during future
air pollution episodes, worst case conditions for meteorology
and periods of peak emissions were assumed. These assumptions,
summarized in Table 31,on the following page, were applied to
the air quality model previously described. Certain assumptions
contained in the model are also given in Appendix C.
Some numerical values were calculated for 1975 and extrapolated
to future years based upon the future number of households,
fireplaces and future traffic projections. The worst case
simulation box model was run for a 24 hour period, with emis-
sion factors entered into each airshed every hour. Wood-burning
rates were entered from 6:00 p.m. to 12:00 a.m. and spaceheatiii:
rates every hour. Traffic rates are a daily average, even
though actual rates per hour differ. Train rates were entered
during assumed hours when a train would be passing through an
airshed.
Particulates
Total contributions in kilograms per day from each source during
the simulation are given in Table 32, following Table 31. As
shown in this table, total contributions from fireplaces ranged
from 64-96 percent of the total.
Table 33, following Table 32, summarizes the simulation model
results for 24 hour average particulate concentrations, by airs': e
The simulation indicated that particulate concentrations will b?
fairly low in all airsheds during the day, rising sharply after
6:00 p.m., when fireplace emissions are entered. Particulate
emissions continued to rise until shortly after midnight when
fireplace emissions are assumed to cease (extinguishing fires
caused a brief rise in particulate emissions).
One drawback of the model is its inability to simulate long-
term peak conditions. The frequency of the condition cannot bp
determined, nor arithmetic or geometric mean values.
The following observations were made concerning the current and
predicted trends for suspended particulates during worst case
conditions (assumed to occur at least once per year):
1975: Analyses of present air quality conditions
show Vail Village and West Vail airsheds above the
federal and state standards. (This is partially
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TABLE 31
SUMMARY OF ASSUMPTIONS FOR WORST CASE SIMULATION MODEL CALCULATIONS.
Cateqory
Meterology
Emissions
Assumptions
Stagnation condition exists on regional (macroscale) level.
Wind direction is upslope from 10 a.m. to 4 p.m. and
downslope the rest of the time.
Wind speed is 0.6 meters per second during downslope
phase and averages 1.9 meters per second during upslope
conditions.
Mixing height of 92 meters is defined by a temperature
inversion — mixing height follows terrain and is
constant during all hours of the simulation.
An ambient temperature of -5°F is used only in fuel
consumption calculations.
Meterorological conditions are the same in all airsheds
during the stagnation condition.
Emissions of total suspended particulates are representa-
tive of a typical winter season peak day.
Emissions due to fuel consumption are constant for 24 hours
and represent 100 percent customer usage.
Train emissions are entered for only 8, 10 or 12 hours
of the simulation, the exact number dependent upon year.
Emissions from fireplaces are constant between 6 p.m. and
midnight and zero for all other hours. A total of 90 per-
cent fireplaces are assumed in use during the evening
hours.
Traffic emissions for any given hour are proportional to
the percentage of the total daily traffic that occurs
during that hour.
Model
Pollutant dispersal is limited by the model boxes. The
dimensions are defined by airshed length, average width
and an inversion height. The cross-section of an airshed
is represented by a trapezoid.
The total mass of particulates is conserved — settling is
ignored.
Mixing is instantaneous — the pollutants are thus uniform-
ly distributed within the airshed volumes.
Three valley configurations are used with no inter-
valley pollutant transport.
During upslope winds, 10 percent of the pollutants leaving
the Avon airshed are transported into the Beaver Creek
airshed and 90 percent enter the Dowd-Avon airshed.
Negligible background concentrations of carbon monoxide
and total suspended particulates are assumed.
The simulation is run for 24 hours — 6 a.m. to 6 a.m. the
next day.
SOURCE: Marlatt and Associates, 1976.
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TABLE 3 2
TOTAL CONTRIBUTION OF SUSPENDED PARTICIPATES
FROM
EACH SOURCF.
CASE
DURING THE 24 HOUR
SIMULATION
WORST
Total Suspended Particulates
Year
1975
1980
1985
1990
Airshed
Bighorn
East Vail
Vail Village
West Vail
Mint urn
Dowd-Avon
Beaver Creek
Avon
Avon-Edwards
Bighorn
East Vail
Vail Village
West Vail
rUnr.urn
Dowd-Avon
Beaver Creek
Avon
Avon-Fdwards
Biphorn
Fast Vail
Vail Village
West Vai]
Mint urn
Dowd-Avon
Beaver Creek-
Avon
Avon-Edwards
Bighorn
East Vail
Vail Village
West Vail
Mint urn
Dowd-Avon
Beaver Creek.
Avon
Avon-Edwards
Wood
Burnlnp,
(kilOR
177.1
99.4
805.7
486.0
101.5
34.6
2t' 6.2
105.8
R44.6
645.8
131.8
131.8
116.6
?"5.2
326.2
157.7
1408.3
R3E.1
216.0
360.7
656.6
810.0
239.8
393.1
164.2
1466.6
1004.4
226.8
481.7
879.1
1086.5
479.5
Space
Heating
rams per day)
3.6
1.3
40.6
6.5
2.8
.3
1.6
.3
4.9
1.3
42.7
8.6
3.5
.8
4.6
.3
6.2
1.4
44.3
n.7
JO. 7
3.8
2.2
12.4
.3
7.5
1.5
46.1
13.0
4.0
3.0
-
16.7
.5
Traffic
9.6
13.6
32.9
25.4
6.1
10.6
9.4
9.3
14.:
17.0
37.2
32.1
7.0
16. J
2.9
19.9
12.6
17.2
19.5
40.9
40.0
7.7
22.6
7.0
33.0
17.3
19.6
21.8
43.3
46.3
8.3
28.5
9.8
43.8
21.9
Trai ns
-
2.3
2.3
2.3
2.3
2.8
2.8
2.8
2.8
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
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TABLE 33
TOTAL SUSPENDED PARTICULATES, 24 HOUR AVERAGES
AIRSHED
1975
1980
1985
1990
micrograms per cubic Meter
i
M
Ul
•Tl
1
Bighorn
East Vail
Vail Village
West Vail
Minturn
Dowd-Avon
Beaver Creek
Avon
Avon-Edwards
67
98
261
388
30
11
0
11
15
90
120
287
457
63
36
26
93
82
119
162
445
670
270
74
151
317
325
141
190
480
743
218
96
206
421
457
Source: Marlatt & Associates, 1976
-------
attributed to the fact that wind direction was
calculated as downslope 18 hours per day, including
the hours of 6:00 p.m. to midnight. As a result,
particulate emissions are drawn into West Vail from
the upwind box. Vail Village.) This condition has
been monitored in Vail; West Vail has no monitor.
All other airsheds are shown below both federal and
state short-term particulate standards.
1980: Conditions are similar to 1975.
1985: Analysis shows Vail Village, West Vail, Min-
turn, Avon, and Avon-Edwards exceeding both state
and federal standards, and Beaver Creek and East Vail
exceeding state standards. The Avon/Avon-Edwards
situations are analogous to Vail Village/West Vail,
with emissions from Avon being drawn into the
Avon-Edwards airshed.
1990: Vail Village, West Vail, Avon, and Avon-
Edwards exceed both state and federal short-term
standards, and East Vail, Minturn, and Beaver Creek
exceed state standards.
The above observations are indicative of air quality trends in
the study area. No conclusions can be drawn from these 24 hour
averages as to the frequency and magnitude of the assumed worst
case conditions. The assumptions used in the model were best
guesses — and the fireplace use assumptions were particularly
high (90 percent from 6:00 a.m. to 6:00 p.m.). The Colorado
Department of Health accepted fireplace use assumptions in a
Vail Associates study of 50 percent from 6:00 p.m. to 9:00 p.m.,
75 percent from 9:00 p.m. to midnight and 25 percent from mid-
night to 3:00 a.m., when ashes are smoldering. (In this study,
the emission factors used for fireplaces were nearly 50 percent
higher.) As a result of the identification of fireplaces as a
major source of particulates, the Colorado Department of Health
will require regular emissions testing in the Beaver Creek area
(soon after the initial development phase), and the Town of Vail
is conducting a fireplace use study in 1976-1977 as a precursor
to a fireplace emissions study which may be conducted in
1977-1978.
Carbon Monoxide
The simulation box model was utilized to calculate CO emissions
from vehicular traffic, trains and household fuel consumption.
Vehicle emission factors were calculated using EPA circular AP-<:"
The results of the simulations showed higher eight hour average
concentrations in 1975 and 1980, sharply declining in 1985 and
1990. Increasing traffic volume was shown on the whole to be out-
weighed by the decrease in emissions factors in future years. Sin
fireplace data for CO could not be calculated, it is impossible to
quantitatively determine the future impact decreases in CO emis-
sions from vehicles may have on CO.
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IMPACTS ON WATER QUALITY FROM
NONPOINT POLLUTION
Thf purpose of this section is to discuss the influence that, the
projected population increases and land use changes will have on
nonpoint contamination of surface and groundwater in the study area.
No new classifications of nonpoint pollution will be created, but
the impacts of the existing types may be increased or decreased.
Urban Runoff Pollution
The projected new housing and recreation facilities will have
considerable effect on stream contamination through runoff from
urban sources, such as streets, parking lots, and rooftops. A
majority of the existing developments and the projected growth
areas are situated along Gore and Beaver Creeks, which are consider-
ably smaller in size than the Eagle River. Urban runoff pollution
is more harmful to the creeks due to their more limited capacity.
The values shown on Table 34 on the following page, represent urban
pollutant loadings which could be discharged to Gore Creek during a
rainfall event of .1 inch depth and 1 hour duration. The values are
estimates, and may be excessive since the research was based on a
typical urbanized area which has land-use characteristics of 75 per-
cent residential, 5 percent commercial, and 20 percent industrial.
Many of the contaminants, particularly lead, copper, and zinc, can
be toxic to a uatic life. Although the values are rough estimates,
they demonstrate that pollution from urban runoff could be highly
detrimental to water quality (runoff from Eagle-Vail and the Bench-
mark vicinity will be less detrimental due to the greater dilution
capabilities of the Eagle River).
Increases in sediment loadings from further urbanization can be
expected due to the fact that approximately 99 hectares (243 acres)
of irrigated land will be converted to urban uses.
Road Maintenance
The development of new housing and recreation areas will require
construction of many new streets and roads. During the winter, sctuu
and road salt will probably be applied to many of these roads at the
same rate and frequency as is the present practice.
sand
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TABLE 34
ESTIMATED POLLUTANT LOADING ON GORE CREEK
FROM URBAN RUNOFF AND WASTEWATER TREATMENT
AT VAIL, COLORADO, 1995
Parameter
Settleable and
Suspended Solids
Urban Runoff Load
Expected Waste
Treatment Plant
Average Discharge'
(Parts Per Million)
352,000.0 10.00
1,062.0 8.30
2,530.0 9.50
165.0 1.70
90.0 .50
115.0 .03
0.2 .001
2.0 .01
6.6 .03
27.0 .16
1,563.0 10.40
Sartor and Boyd, 1972; Pitt and Amy, 1973
BOD
COD
Kjeldahl Nitrogen
Phosphates
Lead
Cadmium
Nickel
Copper
Zinc
Iron
SOURCE:
NOTES;
Ib/hr for 1 hour storm of .1 inch depth (rounded to the nearest
tenth) for a town with the same population as Vail in 1995.
Ib/hr from Vail (rounded to nearest hundredth; Cadmium to nearesl
thousandth).
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I
The State Highway Department applies 4 percent salt/sand mixture to
roads at the average of 3300 Ibs. per mile of highway lane. Ap-
plying this data to the total road miles expected to exist in 1995,
an estimate was made of the amount of salt which would be used. As-
suming 20 storms, and two 4 percent salt/sand applications on all
roads per storm, approximately 500 tons of salt could be discharged
to the Eagle River and its tributaries per year. (As a comparison
runoff from irrigation in the Gunnison Valley contributes over 1
million tons of salt per year to the Colorado River drainage.)
Sludge Disposal
The disposal of sludge through landfilling creates potential pollution
to groundwater or nearby surface water. This practice is currently
utilized by Vail treatment plant and is proposed for all future sludge
generated by both the Vail and Upper Eagle Valley Sanitation Districts.
Lack of adequate or economical sites for drying beds (and subsequent
agricultural use) requires that disposal by landfill be employed.
New landfill sites have not been selected, but such sites must be well
removed from the developed areas for aesthetic and economic (land
cost) reasons.
The effect that sludge disposal will have on water resources will be
highly dependent on the geographical location of the landfill sites,
as well as the soil types, water table location, method of landfilling
used, and the nature of the sludge. Some soil types are very con-
ducive to percolation, while others are less permeable and may contain
clays and minerals which provide ion exchange and absorption capacity.
Alkaline soils may cause some sludge constituents to precipitate, and
nutrients will be taken up in plant life. The soils in the study area
are mostly clays and loams with moderate to low permeability. Their
pH is generally neutral, and they are fairly well suited for
landfill sites. However, many of these valleys lie within areas
currently inhabited or projected for development. The soils of
the upper stream valleys and mountain slopes are loamy to sandy-
loamy- Suitability of these soils for landfill sites is fair to
poor, since permeability is relatively high, and there is the
potential for groundwater contamination. Since new sludge land-
fill sites will probably be located in these areas, preventive
measures should be taken (e.g. locating sites away from water
courses and areas of high water tables, and diaesting and dewater-
ing the sludge before it is landfilled).
Sludge digestion reduces degradable organic (volatile) materials
renders the sludge more concentratable, and greatly decreases the
coliform and disease organism content. Digestion is recommended,
and often required, when the sludge is to be used in agriculture
Although digestion is not currently employed at the Vail plant it
is recommended in the 201 plan for all future sludge generation.
(See Table 35, on the following page, for chemical composition.)
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Construction
Construction activity will be heaviest in the Avon/Beaver Creek
area, moderate in the Gore Valley, Minturn and Arrowhead areas and
very low in the vicinity of Red Cliff. Approximately 16,560 new
living units will be built, 93.5 Km (58.1 miles) of highway and
secondary roads will be constructed and 292 ha (720 acres) of ski,
hiking and equestrian trails will be cleared. Such large scale
disturbances, even though projected to take place over a 20-year
period, will result in significant nonpoint pollution from construc-
tion activity. The most significant impact from these activities
on the aquatic ecosystem is expected to come from increased sediment
loads on into the area's surface waters. Increases in dissolved
chemicals and turbidity will have significant impact on the Upper
Eagle River ecosystem, including a reduction. Non-point pollution
from construction will be worse during the next few years when act-
ivity is expected to be greatest. Once roads and storm sewer lines
have been installed and areas have become revegetated, surface
runoff from these areas will be greatly reduced.
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TABLE 35
TYPICAL CHEMICAL COMPOSITION OF RAW AND DIGESTED SLUDGE
Total dry solids (TS, percent)
Volatile solids
Grease and Fats
Protein
Nitrogen
Phosphorus
Iron
PH
Alkalinity (mg/1 CaCOs)
Organic acids (mg/i HAc)
Zn (zinc) 2
Pb (lead) 2
2
Cd (cadmium)
Cu (copper)
Raw Primarv
Sludge
Percent of TS ^
4.0
65
6-30
25
2.5
1.6
2.5
6
600
500
.17
.07
.036
.07
Digested
Sludge
Percent of TS -1
10.0
40
5-20
18
3.0
2.5
4.0
7
3000
200
.07
.10
.007
.05
SOURCE: Metcalf and Eddy, 1972; Sopper and Kardos, 1973
NOTES;
1 TS = Total dry solids content (all values in terms of percent of
TS except where noted)
averaged values
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IV MITIGATION MEASURES
Mitigation measures are those actions which are either planned
to be, or which could be, incorporated into the project plan.
They usually apply to the primary construction and operation
impacts within the direct control of the sanitation districts.
Most of the biological mitigation measures recommended will be in-
corporated into the design, construction and operations stages of
the proposed action. Since the revegetation program has not yet
been prepared, it is not certain whether each measure will be fol-
lowed exactly as delineated in this chapter.
However, the consulting engineers have planned a comprehensive
revegetation program and intend to design interceptor routes
to avoid the destruction of trees and natural vegetation types.
Since no mitigation measures are recommended for geology and
soils due to lack of impacts, this category has been omitted
from discussion.
Other mitigation measures are not within the direct control of
the sanitation districts since they relate to secondary impacts as-
sociated with growth and development. These include other diver-
sion projects (hydrology), population, land use, and air quality.
Implementation of mitigation measures within these impact areas,
so as not to incur unacceptable secondary impacts, generally re-
quires co-ordination of various governmental agencies within dif-
fering jurisdictions. Such co-ordination and mitigation will be
required by EPA if impacts are significantly adverse. A brief
discussion of current mitigation efforts is presented as an intro-
duction to other possible mitigation measures which may be pursued
and followed. (Mitigation measures for noise and archaeological
resources are implementable and are therefore discussed as such
although falling within the social mitigation measures category.)
BIOLOGICAL MITIGATION
MEASURES
The major impacts on the riparian and lowland meadow communities
will be caused by physical disruption and/or removal of plant
life during construction. The impact on local vegetation
communities due to physical disruption is an unavoidable adverse
impact associated with the proposed action. The adverse effects
can be minimized by containing construction activity to as limited
an area as possible and by employing a thorough revegetation progr
Development of a revegetation program prior to commencement of con
struction, and the inclusion of this program as part of the constr-
tion contract, will ensure its implementation.
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A successful revegetation program depends upon re-establishment
of plant communities similar to those present prior to construc-
tion. Detailed description of existing flora on the interceptor
alignment or at other construction sites prior to construction
should be documented by using local experts (e.g. county extension
agents) and/or photographic documentation.
Mitigation measures which will create a suitable micro-environ-
ment for plant growth and which will aid in the establishment
of a soundly revegetated community are:
- Careful pre-planning of pipeline alignment (location
in areas of good, deep soil) where the new lines are
paralleling existing lines.
- Avoiding steep slopes and areas of high erosion potential.
- Stockpiling of topsoil to spread over the refilled trenches
or other disturbed soils.
- Avoiding large trees and dense vegetation in areas of
new construction.
- Rapid refilling of trenches and initiation of revegetation
efforts.
- Using mulch material to increase success of seed estab-
lishment while minimizing soil erosion.
- Reseeding with a seed mixture including grasses, forbs
and, in some cases, shrubs (depending on the community
disturbed) to aid in the establishment of a more diverse,
natural community -
- Minimizing the number of stream crossings, where possible-
The probability of germination and growth of plants in seeded
areas is greatly increased if seed is drilled into the prepared
seedbed rather than broadcast over it. Seeded species should be
adapted to the site conditions and, to minimize the environ-
mental impacts, native plants should be used. The re-establish-
ment of desirable species in disturbed areas would be enhanced
by reseeding the disturbed areas with desirable grasses, forbs
and shrubs. Recommended species include grasses such as timothy,
tall fescue, smooth brome and reed canarygrass, and forbs such
as sweetclover, cicer milkvetch, birdsfoot trefoil, white clover,
pacific aster and lewis flax; and a few shrubs such as golden
currant, woods rose, black chokecherry, rubber rabbitbrush and
brush cinquefoil. In some locations, it may be desirable to
include an introduced perennial species such as crested wheatgrass
which will produce rapid cover and minimize erosion.
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Wildlife
Impacts on local wildlife, due to disruption or removal of habi-
tat, are unavoidable adverse impacts of the proposed action.
Mitigation measures to minimize impacts on local wildlife are
largely associated with the establishment and implementation of
the revegetation program.
Specific mitigative measures which will be utilized to minimize
the impact of construction activities on wildlife include:
- Minimizing the construction which will occur within
riparian habitat. When disturbance is necessary, the
destruction of woody vegetation, especially trees, will
be kept to a minimum.
- Limiting the width of the pipeline corridor, so that
the least amount of habitat will be disturbed.
- Employing erosion control techniques to prevent silting
of waterways and damage to habitat.
- Revegetation of all disturbed areas.
- Using selective clearance of areas (placement of pipe-
line in areas that will least affect wildlife such as
roadsides or lowland meadows).
- Backfilling as much of the open trench as possible each
day in order to prevent pitfall hazards to wildlife.
The following mitigation measures may not be readily employed,
due to the length of the construction period in cold climates
where the ground is generally frozen from November to April.
However, their implementation would further reduce adverse impact:
to local wildlife.
Limitation of construction activity to the time of year
(August to March); when wildlife are not breeding or carryina
young.
Limitation of construction activity to late in the year
(August to March) when annual vegetation has fully developed
thereby allowing for maximum forage and habitat for wildlife!
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Aquatic Biota
Impacts on the aquatic biota due to construction activities in
or near Gore Creek or the Eagle River are unavoidable adverse
impacts. Rapid degradation of water quality resulting from
selection of Alternate 5 is an unavoidable adverse impact asso-
ciated with the no project alternative. The primary mitigation
actions which will control impacts on the aquatic biota during
construction involve the control and proper maintenance of con-
struction equipment, and a water quality control plan, which
should be developed prior to construction activities and
incorporated into the construction contract negotiations.
Public Law 92-500, Section 404, requires that a permit be applied
for in all areas where stream crossings will occur. This will
be done 90 days prior to construction.
Colorado law requires that construction activities must limit their
induced stream turbidity to less than 10 Jackson turbidity units
(JTU's) (induced turbidity is that turbidity above the natural
condition of the stream). The contractor will coordinate with
the Colorado Water Quality Control Division in order to ensure
that increased turbidity is minimized where possible. The
salient features of a good water quality control plan are:
- Careful preliminary planning of construction with
special emphasis on avoiding in-stream or near-stream
disturbances.
- When in-stream activities are required, the time of
heavy equipment activity should be minimized.
- Pre-construction selection of refueling and equipment
storage locations away from area waters.
- Minimization of vegetative disturbance in areas adjacent
to streams or other areas of high erosion potential.
- Rapid revegetation of disturbed soils.
- Preventive maintenance of construction equipment, espec-
ially fuel and oil reservoirs.
- Phasing of near or in-stream construction activities to
avoid continuous suspended sediment loading.
- Avoiding suspended sediment loading during the time of
year when local fish are spawning (the predominant
spawning species is brown trout, which spawn from late
September to late October).
- Utilize catch basins and settling ponds to retain highly
turbid or fuel contaminated waters produced in side
channels, backwaters or from adjacent disturbed land
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PHYSICAL MITIGATION
fiEA5LJR.CS_
Control of Urban Runoff Pollution
While the subject of this environmental statement is not con-
trol of non-point sources of water pollution, consideration
must be given to all pollution sources, especially in developing
areas, if effective water quality management is to be realized.
Non-point pollution controls can generally be categorized as
source abatement measures, cleaning practices and treatment
methods. These three categories are discussed in general termr
below. The suitability of application of these non-point
water pollution controls to the study area will differ, in
terms of effectiveness and acceptability, from the already
developed areas, such as Vail, to the proposed developments
in the vicinity of Avon. Structural controls, usually asso-
ciated with treatment, are most easily and effectively imple-
mented during construction and continued as a planned element
of the development. Non-structural controls, such as ordinances
against litter and excessive erosion, can be instituted in
existing urbanized areas. The Northwest Colorado 208 water
quality management plan will be addressing non-point source
control in greater detail and should contain specific recom-
mendations for Eagle County.
Although the accumulation of a certain amount of street surface
contaminants in an urban environment is inevitable, much of the
litter that reaches the street and sidewalk can be eliminated,
or at least effectively controlled at its source. This direct
approach to reducing the runoff pollution potential can best be
accomplished through active public education and through effective
and enforceable regulations and ordinances relating to outdoor
cleanliness. In addition to the general anti-litter ordinances,
specific regulation should be directed towards the most prevalent
sources of litter in the urban environment, such as, garbage
and refuse collection, building construction, vacant lots, parking
lots and garages, pet control and food handling establishments.
Street surface contaminants, which represent a major portion of
urban land contaminants, can be partially removed by street
sweeping operations prior to being exposed to runoff. Municipal
street cleaning practices may be improved by increasing the fre-
quency of street sweeping and/or increasing the removal effective-
ness of street cleaning methods.
The treatment of urban stormwater runoff has been approached in
two major ways over the past several years. One approach is
storing the peak flows and discharging them to conventional
treatment plants during low sewage flow periods. The second
approach is to utilize specialized storage and treatment processes
to deal specifically with quantities and types of pollutants fou:id
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in storm water runott. The surLaca sLoj ,i«.n-- poiul is hy i.u i !><•
most frequently proposed method of storing runott. Use ot such
ponds should be considered in the planning of storm drainage
systems for new communities as they will reduce the peak flows of
runoff resulting from urbanization and can also provide erosion
and sediment control for the area during the construction phase
of development. If properly designed, use of pervious vegetated
areas for drainage of impervious surfaces can also be utilized
on new communities with similar beneficial effects in reducing
peak flows and in controlling sediment.
Water Conservation
The relatively high per capita water use (125-150 gal./capita/day)
now being experienced within the study area combined with the
reality of limited water supplies and the potential for stream
flow depletion suggests that water conservation be considered
as a mitigation measure. Conservation of in-house water use
would also have benefits in terms of wastewater treatment
capacity requirements.
In the study area, major water use volumes are associated with
the seasonal winter resort skiing activity. Recognizing that
most of this seasonal water demand is caused by visitors who
rent apartments and condominiums, their water consumption is prob-
ably insensitive to reasonable variations in cost. However,
increasing water rates may increase consideration of modified
water using equipment, such as toilets, showers, and washing
machines, that use less water.
Plumbing fixtures have been designed which reduce water use
without causing inconveniences to the user. It is estimated
that the average shower requires 35 to 40 gallons of water and that
automatic flow regulation can reduce this use by about 50 percent.
Toilet fixtures are available which reduce the amount of water by
more than one-half (from about 8 gallons per flush to 4 gallons),
an important savings, since toilets account for about 45 percent
of all water used in the average household. Dishwashers and clothes
washers are being redesigned to substantially reduce the rinse
water now required. In general, appliances and fixtures now
available can reduce total water use in the average household
by as much as 35 percent.
If water and sewer charges are not an adequate incentive to encour-
age users to install water-saving appliances and fixtures,
revising municipal plumbing codes to require installation of
certain of these devices in all new construction and replace-
ment in existing units may be needed to achieve adequate water
conservation. Within the study area such action could include
local building code revisions requiring water saving fixtures
and fittings in new construction, and in all remodeling projects.
Additionaly, a concentrated public relations program on water
conservation might be initiated.
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Future Water Diversion Projects
There are currently two large transmountain water diversion
projects in the planning stages, Eagle Piney/Eagle Colorado and
Homestake II. The projects and estimated annual diversions were
given in Chapter II. Expected effects could not be determined
due to sparse distribution of gauging stations, and lack of data
concerning diversion periods and rates. The water rights of both
projects are relatively junior, due to their late adjudication
dates. Consequently these projects present no probable harm
to most other appropriators. Diversions made under junior rights
must usually be made during the heavy runoff period, spring
snowmelt. (Homestake I is allowed to divert only from April
to August.) During diversion periods, the demand of senior
diverters downstream will help ensure that streamflow is not depleted
by water exportation. In Colorado, municipal water use is considered
a preferred use over irrigation, and in times of storage, a
municipality may invoke this privilege to obtain water out of
priority. However, this preference of use is not self-executinc;,
but must be exercised by condemnation and the payment of
compensation to the non-preferred user. Therefore, under normal
circumstances, both projects may divert only within their
priority-
Maintaining adequate flows to support fish life will also help
to insure that streamflows are not depleted to an undesirable
level. As of 1973, Colorado statutes provide that water may
be appropriated for the purpose of maintaining adequate fish-
flows. New decrees may be adjudicated or existing rights may
be purchased and a transfer of use made for this purpose.
Recommendations for minimum flows are made by the Colorado Divi-
sion of Wildlife to the Colorado Water Conservation Board. Such
a procedure has not yet been undertaken on the Upper Eagle River
or its tributaries. Should this tool be used, the purchase of
water rights senior to those of the exportation projects would
be necessary to insure that their diversions were regulated
for preserving fish flows. Recommendations have been made for
Gore Creek and are contained in Table 36 on the second following page,
Diversions made on government lands or for government-funded
projects may be regulated through written agreements with
the affected agencies. The right-of-way agreements between
the Homestake I project and the BLM include certain stipula-
tions relating to limiting diversion periods and maintaining
minimum streamflows, as recommended by the U.S. Fish and
Wildlife Service for preserving fish habitats. Regardless of
legal priority or water availability, these minimum flows must
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be maintained through or around all diversion or storage
structures of the Homestake I Pro-ject, or they must petition and
pay damages.
Although such written agreements have not yet been formulated
for the new diversion projects, they will probably contain
similar stipulations.
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TABLE 36
MINIMUM STREAMFLOW RECOMMENDATIONS
BY COLORADO DIVISION OF WILDLIFE
FOR SUPPORTING FISH HABITAT
MINIMUM FLOW
STREAM (Cfs)
Pitkin Creek 3
Booth Creek 3
Red Sandstone Creek 4
Gore Creek 51
Gore Creek 72
Gore Creek 7.53
Black Gore Creek 9
Bighorn Creek 3.5
Beaver Creek
May 1 - Sept. 30 12.0
Oct. 1 - April 30 4.0
Headwaters to Black Gore Creek
Black Gore Creek to Red Sandstone Creek
Red Sandstone Creek to Eagle River
SOURCE: Colorado Division of Wildlife
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SOCIAL MITIGATION
MEASURES
Social mitigation measures are those related to population growth
and land use, air quality, noise and archaeologic, cultural and
historic sites.
Population and Land Use
Growth is expected in parts of the study area— new growth in Avon/
Beaver Creek and expanded growth in Vail and Minturn. Various
efforts to control growth in the United States have not been
completely successful, although the rate of growth has been
slowed by such methods as imposing excessive utility tap fees,
a moratorium on new taps due to a lack of treatment facilities,
and restrictive zoning covenants. In the study area, wastewater
treatment facilities will not prevent development from occurring,
since alternative methods of treatment could be sought by
developers, resulting in a proliferation of small plants or
package plants.
One mitigation measure for reducing high rates of growth is down-
zoning, which will reduce future population density. Vail is
currently pursuing a growth management plan. Although data is
unavailable as to the methods which will be recommended, it is
probable that down-zoning will continue to be one method, justified
through a facilities/services analysis, which discloses the
financial impacts to the community.
In the future, restrictive zoning could be applied in the area
surrounding Beaver Creek to confine development and prevent
scattered development patternsand consequent per capita increases
in the costs associated with some facilities, e.g. sewer lines.
Any zoning changes proposed in an area from a less restrictive
t0^K TK^ restrictive category must be considered in consultation
with the owners of the land. Otherwise, these changes could be
contested. The Federal courts have ruled that down-zoning may
be interpreted as a taking, without compensation, and cannot be
snroc •
Future land use policies and controls will essentially be the
responsibility of the Eagle County Planning Commission and
County Commissioners in cooperation with local units of government
who control local zoning. The past development patterns at
Vail may provide an impetus to exert more County control in
the Avon/Beaver Creek area. v-wutruj. in
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Air Quality
Vail has been identified as a potential problem area for air
quality problems and has received some attention in the
mitigations area. The Town of Vail is conducting a pollution
testing program and a fireplace use study. Next year, it is
hoped that a fireplace emissions study will be conducted in
order to assess the magnitude of emissions from this source and
the potential impact that any of the following measures would
have in reducing future air quality problems. Vail has an on-
going program of reducing auto emissions through the use of
auto-free zones and restricted parking to enhance and maintain
a pedestrian oriented community -
The following mitigation measures for fireplaces and mobile sourr;-
were drawn partially from the Town of Vail's suggestions. They
are intended as a possible shopping list from which a future
emissions control program may be drawn.
Fireplaces— These mitigation measures may be taken individually
or in combination with other strategies to limit fireplace
emissions.
Fuel Storage
Description: Require firewood to be stored in outside storage
areas or in basement areas.
Advantages: No direct research or cost associated with the
program.
Disadvantages: Difficult to obtain cooperation of lodge owners
and difficult to enforce.
Effectiveness; If inconvenience of obtaining fuel were great
enough, a portion of emissions could be reduced.
Timing: Implementation within one year given no legal objections.
Legal Authority; Local ordinance passed by Town of Vail Council
and/or County Commissioners.
Public Acceptance; Negative response due to inconvenience of
visitors.
Transfer of Fireplace Rights
Description; Similar to transfer of development rights; a develop*'
would be able to transfer an allocated number of fireplaces to
another airshed providing it did not adversely affect that airshed.
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Advantages: Reduce potential emissions in airsheds with high
particulate concentrations.
Disadvantages; Will only redistribute sources, and put the burden
on future developments.
Effectiveness; Extensive modeling would need to be conducted
before effectiveness could be evaluated.
Timing; Implementation within two to three years.
Legal Authority; Local ordinance by Vail Town Council and/or
County Commissioners.
Public Acceptance: Negative response from dvelopers — no response
from the general public.
Zoning Density Reduction
Description: Through zoning procedures a development desiring
fireplaces would have its unit density reduced according to the
number of fireplaces desired. For example, for each fireplace
in a development, one dwelling unit would be eliminated.
Advantages: Would severely restrict numbers of new fireplaces
constructed in the Gore Valley.
Disadvantages: The burden would be placed on the future
developments.
Effectiveness: The number of sources could remain at near present
levels so that concentrations would not become much worse.
Timing: Implementation within two years without legal objections.
Legal Authority: Local ordinance passed by the Vail Town Council
and/or County Commissioners.
Public Acceptance; Negative response from the developers; no
major response from the general public.
Phase-Out
Description; Declare a moratorium on building any new fireplaces.
Advantages: No research or direct cost associated with imple-
mentation.
Disadvantages; Declin.e in skiing vacationers due to a loss in
aesthetic enjoyment; places entire burden of air quality maintenance
on future developers.
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Effectiveness; Eliminates a significant percentage of future
particulate emissions but fails to control existing emissions
in Gore Valley.
Timing: Implementation feasible within one year assuming no
legal obstacles.
Legal Authority; Building codes passed by the County Commissioners
and/or Town of Vail Council preventing developers or homebuilders
from constructing fireplaces.
Public Acceptance; Little response since this measure would not
have an immediate impact on existing residents; major response
from prospective residents and developers.
Fuel Conversion
Description; New or existing fireplaces would be required to
either burn natural gas or use electric power.
Advantages; Aesthetic enjoyment would be semi-retained.
Disadvantages; Unfeasible considering the current "energy crisis"
and short supply of natural gas.
Effectiveness: Eliminates a significant portion of the particulate
emissions while adding only a negligible amount of new emissions.
Legal Authority; Local ordinance passed by the County Commis-
sioners and/or Town of Vail Council.
Timing; Dependent on the availability of natural gas and electric
power.
Public Acceptance; Negative response since the cost of natural
gas or electricity would be higher than the present cost of wood
and loss of aesthetics.
Fireplace Controls
Description; Require particulate control equipment to be installed
on existing and new fireplaces.
Advantages: Allow woodburning fireplaces while controlling
emissions at the source.
Disadvantages; Indirect cost of research and development of
control equipment and direct cost of installation and maintenance.
Effectiveness; Assuming a 90 percent control efficiency, a
significant percentage of the particulate emissions would be
eliminated.
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Timing: Dependent on the length of research and development
and prototype testing (approximately three to five years).
Legal Authority: Local ordinance passed by the County Commis-
sioners and/or Town of Vail Council.
Public Acceptance; Negative response due to the economic
burden on the individual condominium, home or lodge owner.
Emission Allocation
Description; Allow the maximum number of fireplaces and associ-
ated emissions in an airshed that would not cause the particulate
NAAQS to be exceeded.
Advantages; Development would be distributed into each airshed
so as to allow fireplace use while maintaining the NAAQS.
Disadvantages: Land ownership and zoning may prevent redistribu-
ting development and the county has approved future development
location.
Effectiveness: Balance particulate emissions with the assimilative
capacity of the ambient air to maintain NAAQS but create
additional mobile source emissions (CO & HC) due to longer travel
distances.
Timing: Implementation would be contingent upon the successful
relocation of planned developments using emissions as a constraint.
Legal Authority: Changes in the Eagle County Master Plan and
possible state intervention (Land Use Commission) to prevent
planned development densities and locations previously approved.
Public Acceptance; Little response since this measure would not
have an immediate impact on existing residents hut major response
from prospective residents and developers.
Special Operating Conditions
Description; Woodburning or fireplace usage would be prevented
during poor dispersion conditions and require a seasonal meteorol-
ogist employed by the county (also meteorological stations).
Advantages: Applied only during the time it is needed and allows
fireplace usage during good dispersion conditions.
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Disadvantages: Difficult to enforce and requires both a public
alerting system and "police action" for violations.
Effectiveness: Eliminates a significant percentage of particulate
emissions on "worst case" days where citizen cooperation is
essential.
Timing: Implementation feasible within two years assuming no
legal obstacles.
Legal Authority: Local ordinance passed by the County Commissior.ars
and/or Town of Vail Council (apply to AQMA study area, not
county-wide).
Public Acceptance: Negative response due to government inter-
vention into public enjoyment.
Mobile Sources— The following mitigation strategies are directed
at mobile sources:
Pedestrianization
Description; Close off local streets and create pedestrian malls.
Advantages: No major costs associated with implementation —
Aesthetic considerations.
Disadvantages: Inconvenience to visitors and locals with possible
increased cost of deliveries.
Effectiveness; Reduce CO emissions by at least 25% by reducing
low speed traffic, but fails to control any freeway or arterial
emissions.
Timing; Implementation feasible within one to five years.
Legal Authority; Ordinance passed by the Town of Vail Council
and/or the County Commissioners.
Public Acceptance: Previous attempts have generally had a
positive response due to safety, aesthetics, and economics.
Public Transportation
Description; Major bus system operating within the Gore Valley.
Advantages: Reduce auto emissions without major restrictions on
driving.
Disadvantages: Direct cost of operating the bus system.
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Timing: Increased bus system would be dependent on additional
Federal monies which could take two to five years.
Public Acceptance: Positive response due to low cost to public,
and general reliability of system.
These ten mitigation measures do not include all possible
alternatives. Combinations of two or more of the strategies
are possible. For example, fireplaces in lodges could be
required to burn natural gas and new residential fireplaces
could be required to have emission control devices. Therefore,
a weighted combination of strategies may meet the political,
legal, and social requirements.
Mitigation selection should not be based solely on maintaining
air quality standards but should include many other considerations.
Alternatives should be reviewed for their feasibility within
the political and legal framework of Eagle County.
Noise
Mitigation measures for noise from construction equipment will
include proper maintenance and mufflers. The need for special
mitigation measures such as noise buffers will not be necessary.
Archaeology, Paleontology and Historic Sites
The proposed action has been discussed with the staff of the
Colorado State Archaeologist. Their view is that the disturbed
nature of the project impact area makes conducting archaeological
surveys to identify previously unrecorded resources largely
impractical, since previous disturbance would likely have des-
troyed all surficial manifestations. However, if subsurface
materials are uncovered, impacting work must be halted until the
site is evaluated in terms of the eligibility criteria of the
National Register of Historic Places.
Should a site be determined eligible for the National Register,
plans for the mitigation or avoidance of adverse impacts must
be properly arranged.
The Office of the State Archaeologist recommends that a know-
ledgeable person be retained during construction to identify
potential archaeological resources.
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V FINANCIAL CONSIDERATIONS AND IMPACTS
The rates and charges of the Vail Water and Sanitation District
and the Upper Eagle Valley Sanitation District have been analyzed
for the following:
- Adequacy of present charges to meet future costs.
- Adequacy of present charges to finance the needed
sewer line and plant improvements recommended in
the 201 Facilities Plan.
- Fairness in terms of each user paying his fair share
of the cost of operations and the cost of growth.
The data presented in this document is a condensed version of a
nore detailed and lengthy financial analysis and rate study pre-
sented to the VWSD and UEVSD Boards in January-February, 1977.
Numerous detailed financial projections, population distributions,
and other supporting information have been omitted for the sake of
brevity.
RATES AND
CHARGES
Vail Water and Sanitation District
The total estimated cost of the proposed plant and line improve-
ments for Vail is $4,145,000. The 75 percent federal portion of
this project is an estimated $3,109,000. An election authorizing
a bond issue for the remaining $1,036,000 is recommended for 1978.
In addition, the Vail Water and Sanitation District should adopt
a method of computation of tap fees which ensures that each new
user will pay his proportionate share of both the present and
future capital costs of the plant and system. It is estimated
that this would increase sewer tap fees from $150 per unit
(10 points) to $540 per unit.
An increase in sewer rates is recommended from $5.75 per unit per
month to $6.55 per unit per month.
These increases should be instituted early in 1977. The plant
construction and sewer line expansion are only a small portion
of the financial need for a rate increase. From 1977 to 1980,
a large portion of the bonds attributable to the sewer system
will be retired, placing considerable financial demands on the
Vail District's revenues.
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Upger^Eagle Valley Sanitation District
The total estimated cost of the Facilities Plan plant and line
improvements for the Upper Eagle Valley Sanitation District is
$5,353,000. The 75 percent Federal portion of this part of the
project is an estimated $3,962,000.
A general obligation bond issue of $1,391,000 is recommended for
1978 to finance Upper Eagle's improvements to lines and plants.
An election authorizing a bond issue for the $1,391,000 local
share is recommended.
The present bond issues should be refunded in early 1977 to spread
the heavy debt service schedule over the next few years. This
refunding measure will net the district an interest savings of
$25,000 through 1993, the term of the present bonds.
Tap fees, based upon the principle of proration of capital expenses
to each user should be increased from $700 per unit to $800 per
unit.
An increase in sewer rates is recommended from $6.30 per unit to
$7.90 per unit per month. Inflation, increased debt service for
existing debt (even with a 1977 refunding and bond issue) and
expansion of the existing plant will contribute to this increase.
These rate increses should be instituted in early 1977.
Bighorn Area of UEVSD
This analysis assumes that the wastewater flows produced by the
Bighorn area of Vail, currently within the UEVSD, are to be
treated at the Vail plant, and a contract for services is to be
signed between the two districts.
Prior to contract negotiation, Vail's expenses attributable to
the Bighorn area must be apportioned; whether costs attributable
to Bighorn should be allocated on the basis of population, units,
or flow must be determined; and responsibility for the enlarge-
ment of sewer lines through Vail serving Bighorn must be assigned.
Other options to a contract for Bighorn treatment are discussed
in Appendix 0.
The institutional analysis states that there are no legal
obstacles blocking either merger of the two districts, partial
consolidation of the Bighorn area into the VWSD, or retention of
the status quo.
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Upper Eagle-Vail Village West Contract.
Tap fees and sewer rates for the Upper Eagle Valley Sanitation
District service area are calculated as though all rates and fees
could be changed by a unilateral action of the Board. In fact, a
contract between the Vail Village West Water & Sanitation District
and Upper Eagle freezes the rates and fees charged for sanitation
in the Vail Village West service area through 1990.
If these contract terms remain in force, the monthly rate increase
for Upper Eagle residents required would be 34 percent instead of
the recommended 25 percent. This would mean that instead of
increasing rates from $7.90 per unit per month, rates would he '..
to increase to $8.45 per unit per month.
Red Cliff Water & Sanitation District
The Red Cliff sewer system requires significant improvement. /Al-
though that community is seeking 100 percent federal funding from
other non-EPA sources, the Vail and Upper Eagle Districts shou ic;
stand ready to include Red Cliff in their grant applications if
requested.
NO FEDERAL FINANCING -
NO ACTION ALTERNATIVE
On all options 75 percent federal participation in new capital
financing has been assumed. This section addresses the impact
on the two districts should EPA take "no action" in funding
the treatment works.
General Impact
Installation of plant improvements to achieve the quality of
effluent probably would not be possible. The bond issue
interest costs may be so high that construction of the facilitj
described in the 201 Facilities Plan might not be possible.
Adequate construction capital may not be available. By
adding three times the present local capital costs to the
projects of the two districts, the credit of either or both
of the two districts in the municipal bond markets may be
exceeded. Bond buyers may view the projects as unfeasible.
Interest rates, hence cost to the area served, would be higher
than the 6.5 percent estimated,if the bond issues were found
feasible.
Residents of the two districts might not vote the issuance
of general obligation bonds for such a large amount of capital.
This would leave the other financing alternative of revenue
bonds, which are probably made unfeasible by the addition of
three times the present estimated capital costs.
For simplicity, it has been assumed that the Districts could
finance the expansion and upgrading of facilities recommended.
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An interest rate of 7.5 percent on 20-year general obligation
bonds has been assumed, which might be low in reality -
Impact on Vail Water & Sanitation District Rates
Capital costs for the VWSD would increase from $1,036,343 to
$4,145,371.
Instead of a service charge increase of 12 percent being needed,
the increase would be 45 percent, to a monthly service charge
of $8.50 per unit (10 points per month).
Instead of tap fees increasing from $150.00 to $540.00 per
unit (10 points), they would increase to $1,175.00. This is
an increase of 783%. It is likely that this significant
increase in tap fees would reduce the number of taps collected
by the Vail District at least for a few years and, therefore,
cause an additional increase in monthly service charges as tap
fee revenue may fall off.
Impact on Upper Eagle Valley Sanitation District Rates
Capital costs for the Upper Eagle Valley District would increase
from $1,391,000 to $5,353,000.
Annual debt service on the new debt for plant and interceptor
expansion would increase from $126,000 per year to $525,000
per year. This is a net annual increase of $399,000 and would
occur for each of the next 20 years.
Payments to Vail Water & Sanitation District for the capital
costs of the Bighorn area would increase by a net of $80,000
for 1978 through 1981.
Payments received from Vail for their annual share of the
capital costs of the sludge treatment facility would increase
by a total of $33,000 through 1981.
Using the refunding bond option previously recommended to
establish Upper Eagle's rates, a sewer service of $10.55 per
unit per month would be required.
Tap or connection fees for the Upper Eagle Valley District
would have to increase from $700 per single family unit to
$1,360 per single family unit. This increase, as in the Vail
District, would probably reduce the number of expected units
and tap fees, at least in the immediate future, and cause an
additional amount of cost to the District to be borne by the
sewer and service charges.
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It should be underlined that in the case of both Districts,
the increase in capital costs caused by a lack of Federal
funding very well might cause the two Districts to be unable
to issue sufficient bonds to cover project costs, and, hence,
make the two Districts unable to accomplish the plant and
interceptor improvements necessary for a quality effluent to
meet State and Federal standards.
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VI IRREVERSIBLE AND IRRETRIEVABLE COMMITMENTS OF RESOURCES
The loss of valuable natural resources as well as the energy
consumption requirements of projects have become a primary
concern from an environmental protection/conservation stand-
point. Natural resources which will be consumed or utilized
in the construction of facilities and in the manufacture of
equipment include concrete, steel and other metals, plaster,
glass, and wood. Other considerations are land costs, con-
sumption of energy, operation and maintenance costs, abandon-
ment of resources, loss of agricultural production and the
replacement frequency for various types of equipment.
Due to the complexity of these and other economic considerations,
a gross economic cost/benefit comparison was performed by
the consulting engineers utilizing the EPA publication
A Guide to the Selection of Cost Effective Wastewater Treatment
Systems. The figures, contained in the consulting report,
indicate cost comparative numbers rather than specific
project cost estimates which cannot be prepared without
detailed engineering analyses. Excluding Alternative 4,
which did not include any costs for the Vail Water and
Sanitation District, the annual costs range from $1,441,000
to $1,567,000 (a range of 8.7 percent). These costs include
capital costs and annual operation and maintenance (over an
18 year amoritization period) of: wastewater treatment
(primary and secondary), sludge treatment and disposal,
pipeline replacement and land costs. The figures generated
represent, in terms of the utilization of total resources,
energy and materials related, only a comparison. Because
they use national average costs, they cannot be related to
the study area and its problems (e.g., the difficulty of
finding sludge disposal areas near the Vail Plant which
necessitated the abandonment of sludge facilities at Vail,
or the prohibitive cost of land application in an area with
a relatively short growing season). The comparative costs,
given as annual figures are:
Alternative Annual cost Percent of Highest
$1,000 Yearly Cost
1 - 1,567 100
2 - 1,513 96
3a - 1,406 89
3b - 1,564 99.8
3c - 1,374 88
3d - 1,441 92
4 l - 954
Does not include Vail costs.
It is apparent that total reliance upon a cost comparison for
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evaluation purposes is not practicable. Also important are
the environmental losses (wildlife habitat), growth and
possible sprawl, and other issues addressed elsewhere in
this report. The no action alternate (5), while requiring
no depletion of natural resources or energy, would cause
significant degradation of the environment unless growth was
limited through a complete building moratorium. Moratoria,
however, have been looked upon by the state and federal
courts as an unconstitutional means of placing a ceiling on
development.
From an energy conservation standpoint, two alternatives
require the utilization of more resources, Alternative 2 in
which the Vail Plant is abandoned and a new plant built at
Dowds, and Alternative 3b, 3d in which a new plant is constructed
in the Squaw Creek Area. The Squaw Creek alternative eliminates
the costs of pumping Arrowhead flow, but requires new sewer
line construction through an area of potential growth and
development which is currently rural/agricultural.
In summary, all alternatives will require a significant
amount of natural materials and energy in order to maintain
high levels of water quality in the future. Each alternative
must be assessed in terms of the need to balance some economic
considerations with environmental conditions.
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VII THE RELATIONSHIP BETWEEN LOCAL SHORT-TERM USES OF MAN'S
ENVIRONMENT AND THE MAINTENANCE AND ENHANCEMENT OF
LONG-TERM PRODUCTIVITY
THE SOCIAL
ENVIRONMENT
Expected increases in population levels have brought on the
need for wastewater system expansion and improvements. If
the duration of the increase was short-term, the long-term
benefits for the enhancement and maintenance of water quality
would then be questionable. Since the magnitude of future
development is as yet undetermined, staging of treatment
plant works must address the problem of potential adverse
effects from over-capacity, which has been accomplished by
the 201 plan.
THE PHYSICAL
ENVIRONMENT
Expansion and upgrading of sewerage facilities will remove
the land in the vicinity of construction activity from pre-
sent uses (e.g., wildlife habitat, agriculture and various
urban uses). The disturbance will be localized for the most
part, within the construction easement. After construction,
revegetation will return most land to its former uses, with
the exception of small parcels where new plants and expan-
sions occur. Due to the secondary impacts of growth, the
long-term uses of an estimated 34 developable parcels will be
changed from open space and agricultural to recreational and
residential.
THE BIOLOGICAL
ENVIRONMENT
The immediate short-term effects of the proposed project, on
the biological system of the Upper Eagle River Valley en-
vironment, include a loss of vegetation and wildlife. The
construction phase of the project will temporarily lower the
quality of the aquatic and terrestrial habitat. Preservation
and enhancement of habitat quality will ensure the maintenance
of existing ecological interrelationships and the continued
health of both natural and human components of the ecosystem.
Actions that significantly decrease the quality or quantity
of the Eagle River or Gore Creek by either severe ecosystem
disruption or by direct contamination will have long-term
impacts on future productivity of the ecosystem as well as
the health of populations in and adjacent to these waters.
Protection of the Eagle River and Gore Creek is critical
during construction, and all feasible mitigation measures
will be undertaken to prevent any disturbance that is severe
or of long duration.
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The project represents a significant mitigation measure
in the prevention of continued degradation of areawide
water quality. The current and potential future problems
have been discussed in the water quality section. The
continued or expanded use of existing leaching fields and
septic systems between Avon and Squaw Creek could be reduced
through the provision of extended lines, particularly if
a new plant is built downstream.
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GLOSSARY
Activated Sludge Principle - Sludge floe produced in raw or
settled wastewater by the growth of zoogleal bacteria and other
organisms in the presence of dissolved oxygen and accumulated
in sufficient concentration by returning floe previously formed.
Aeration - (1) The brining about of intimate contact between
air and a liquid by one or more of the following methods: (a)
spraying the liquid in the air, (b) bubbling air through the
liquid, (c) agitating the liquid to promote surface absorption
of air.
Aerobic Digestion - Digestion of suspended organic matter by
means of aeration.
Aerobic Digestion Tank - Tank used in aerobic digestion. See
Aerobic Digestion.
Alluvial Groundwater - Groundwaters which are hydrolically
connected to surface waters but are found in the valley fill
deposits (alluvian) adjacent to these waters.
Anaerobic Digestion - The degradation of organic matter brought
about through the action of microorganisms in the absence of
air or elemental oxygen. Usually refers to waste treatment by
fermentation.
Biological Oxidation - The process whereby living organisms
in the presence of oxygen convert the organic matter contained
in wastewater into a more stable or a mineral form.
Chlorination - The application of chlorine to water or waste-
water, generally for the purpose of disinfection, but frequently
for accomplishing other biological or chemical results.
Chlorine Contact Chamber - A detention basin provided primarily
to secure the diffusion of chlorine through the liquid.
Comminution - The process of cutting and screening solids
contained in wastewater flow before it enters the flow pumps or
other units in the treatment plant.
Comminutors - Machines used in comminution.
Contact Stabilization - A modification of the activated sludge
process in which raw wastewater is aerated with a high concen-
tration of activated sludge for a short period, usually less than
60 min., to obtain BOD removal by absorption. The solids are
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subsequently removed by sedimentation and transferred to a
stabilization tank where aeration is continued further to oxidize
and condition them before their reintroduction to the raw waste-
water flow.
Contact Tank - A tank used in water or wastewater treatment to
promote contact between treatment chemicals or other materials
and the body of liquid treated.
Decibels (dB) - A logarithmic measure of the sound intensity
normalized to a reference pressure.
Dewatered on Drying Beds - To extract a portion of the water
present in a sludge or slurry.
Facilities Plan - (Also referred to as a 201 Facilities Plan).
A plan drawn up under Public Law 92-500 under Section 201. Sect
201 authorizes federal construction grants for 75 percent of
the planning, design and construction costs of new or improved
facilities. Stage One is the Facilities Plan, Stage Two is Desi •
and Stage Three is Construction.
Final Clarifier - (Also referred to as Sedimentation Tank). A
unit of which the prime purpose is to secure clarification. If
"final" clarifier, it is used in the final clarification stage.
Grit Removal - The heavy suspended matter (e.g. sand, gravel,
cinders) present in water and wastewater which must be removed
to prevent damage to wastewater facilities. Removal is usually
accomplished through the use of grit chambers.
Manual Bar Screen - A manually operated screen used for the
removal of coarse floating and suspended solids.
Mixing Depth - The height above the surface through which
relatively vigorous vertical mixing of the atmosphere occurs.
Normally it is at a minimum during the morning breakup of a
nocturnally formed temperature inversion.
pH - The negative logarithm of the hydrogen-ion concentration.
The concentration is the weight of hydrogen-ions, in grams, per
liter of solution. Neutral water, for example, has a pH value
of 7 and a hydrogen-ion concentration of 10". The scale, whose
numbers range from 0-14, with 7 representing neutrality, expressc.
both acidity (below 7) and alkalinity (above 7).
Primary Clarification - The settling process by which a reduction
of the concentration of suspended matter in a liquid is made.
If primary, it is done ahead of biological treatment.
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Richter Scale - A logarithmic scale for expressing the magnitude
of a seismic disturbance (as an earthquake) in terms of the energy
dissipated in it with 1.5 indicating the smallest earthquake that
can be felt, 4.5 an earthquake causing slight damage, and 8.5 a
very devastating earthquake.
Screening - The removal of relatively coarse floating and suspended
solids by straining through racks or screens.
Sludge - (1) The accumulated solids separated from liquids, such as
water or wastewater, during processing, or deposits on bottoms of
streams or other bodies of water. (2) The precipitate resulting
from chemical treatment, coagulation, or sedimentation of water or
wastewater.
Supernatant - The liquid standing above a sediment or precipitate.
Thickened by Flotation - Thickening by the raising of suspended
matter to the surface of the liquid in a tank as scum - by aeration,
evolution of gas, chemicals, electrolysis, heat, or bacterial decom-
position, and subsequent removal of the scum by skimming.
Vacuum Filtration - Filtration performed with a vacuum filter,
consisting of a cylindrical form mounted in a horizontal axis,
covered with a filter cloth, and revolving with a partial sub-
mergence in liquid. A vacuum is maintained under the cloth for
the larger part of the revolution to extract moisture. The cake
is scraped off continuously.
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APPENDIX A
OTHER FEDERAL WATER QUALITY PROGRAMS
EPA is responsible for the control of toxic substances that may
be discharged into the nation's waters through the Toxic Sub-
stance Program, which is designed to reduce the effects of toxic
chemicals on humans and the aquatic environment.
Other federal agencies that have water quality programs include
the U. S. Geological Survey (USGS). Their experience in ground
and surface water hydrology is especially helpful in monitoring
mineral quality. The USGS is currently monitoring water quality
for the areawide 208 program. The Soil Conservation Service of
the Department of Agriculture has an erosion control program,
which includes reservoir construction. The SCS can advise on
land management practices for erosion control.
The Department of Housing and Urban Development administers
grants to state and local agencies for the formulation and coor-
dination of community development plans and programs (general
plans are commonly known as HUD 701 Plans) The U. S. Forest
Service has developed a watershed management monitoring program
designed to gather baseline water quality data. These data will
be used to determine future effects of silviculture on water
quality and to evaluate watershed management methods.
Integration of individual state water quality plans will be
coordinated by the Bureau of Reclamation and presented as the
Western United States Water Plan. The purpose of this plan is to
identify and direct future efforts in satisfying the most criti-
cal water quality requirements. The Westside Study teams have
conducted a comprehensive study of the existing and future water
quantity requirements of the eleven western states.
The Corps of Engineers permit program, Section 13, commonly called
the Refuse Act of the 1899 Rivers and Harbors Act, gave the
Corps the task of regulating all industrial discharges. Section
10 of the Act is still in effect. (Other sections were repealed
with the enactment of new laws, e.g. PL 92-500) It concerns in-
dustry in the construction of outfalls and other obstructions in
navigable waters. This program requires that a permit be
obtained from the Corps of Engineers.
OTHER COLORADO WATER QUALITY PROGRAMS
The Colorado Individual Sewage Disposal Systems Act directs the
Colorado Department of Health (CDOH) to adopt minimum standards
for the location, construction and performance of these systems.
Local health authorities are required to adopt rules and
A-l
-------
regulations for individual systems, pursuant to the minimums
established by the state. A permit is issued by the local Board
of Health when the required data is submitted by the applicant.
Colorado Senate Bill 1963 requires state certification for
treatment plant operators, and all wastewater treatment plants
must be under the supervision of operators holding proper
certification. The certification program is regulated by the
plant operators Certification Board of the CDOH.
The Division of Wildlife of the Colorado Department of Fish and
Game is currently taking an inventory of certain streams and
rivers in the study area to obtain data for making
recommendations for maintaining minimum stream flows to support
fisheries. Colorado Senate Bill 97 provides that the Colorado
Water Conservation Board can appropriate water through the state
water law system for the purpose of insuring that surface flows
remain adequate to maintain fish life. Appropriations can also
be made for maintaining minimum water levels in natural lakes.
Colorado Water Quality Standards
Water Quality Standards for surface waters exist for each
classification. All streams are placed into one of four classes,
summarized in Table A-*-!. The Eagle River, Gore Creek, and all
associated tributaries are classified BI.
Proposed Water Quality Standards — Revised water quality standards
are being prepared for Colorado by the Committee on Colorado Water
Quality Standards and.Stream Classification, Water Quality Control
Commission. The new system will classify waters as recreational,
aquatic life supporting, agricultural, or water supply. Some
classifications have been subdivided (cold water/warm water,
groundwater/surface water), with specific proposed water quality
standards.
The standards are grouped into categories including physical,
pollutional indicators, toxic metals, other toxicants, inorganic
minerals, organics (including pesticides), radiological, and
biological. The standards will be recommended to the Colorado
Water Quality Control Commission for adoption. The proposed
classification system and water quality standards are shown on the
following six pages.
Wasteload Allocations
Wasteload allocations determine the amount of designated pollutants
which can be discharged to a receiving stream without exceeding the
A-2
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TABLE A-1
SUMMARY OF COLORADO STATE WATER QUALITY STANDARDS4
I
Ul
Parameter
Settleable solids
Floating solids
Taste, odor, color
Toxic materials
Oil and grease
Al
free
free
free
free
A2
Bl
B2
Standard
from
from
from
from
Cannot cause a
free
free
free
free
from
from
from
from
Cannot cause a
free
free
free
free
from
from
from
from
Cannot cause a
free
free
free
free
fron
from
from
from
Cannot cause a
Radioactive material
Fecal coliform
bacteria b
Turbidity
Dissolved oxygen
pH
Temperature
film or other
discoloration
Drinking water
standards
Geometric mean; 400-
12,000 7-day average
film or other
discoloration
Drinking water
standards
Geometric mean; 400-
12,000 7-dey average
film or other
discoloration
Drinking water
standards
Geometric mean; 400-
12,000 7-day average
film or other
discoloration
Drinking water
standards
Geometric mean; 400-
12,000 7-day average
200-6,000 30-day avg. 200-6,000 30-day avg. 200-6,000 30-day avg. 200- 6,000 30-day avg
"Whatever is necessary to protect the public health in the stream classification discharged
Fecal strepto-
coccus
No increase of more
than 10 J.T.U.
6 mg/1 minimum
6.5 - 8.5
Maximum 68 F; maxi-
mum change 2°F
Monthly average of
<20/100 ml from
five f. '.'TT/plef in
30-in" per Lod
No increase of more
than 10 J.T.U.
5 mg/1 minimum
6.5 - 8.5
Maximum 90°F; maxi-
mum change:
streams - 5°F
lakes - 3°F
Monthly average of
<20/100 ml from
five samples in
30-day period
No increase of more
than 10 J.T.U.
6 mg/1 minimum
6.0 - 9.0
No increase of more
than 10 J.T.U.
5 mg/1 minimum
6.0 - 9.0
Maximum 20°C [68°F]; Maximum 32°C [90°F];
maximum change ;
1°C [2°F]
maximum change:
streams 3°C [5°F],
lakes 2°C [3°F]
19 March 1974; ?fi~ri_ive date •- 19 Jtm,- 197/,. " ••• n .-• i-5 o U-: > v i1.- i-; > -^>d .
"Late Department of Health, Water UiaUt\ Standards and : trenr. Classification, 1974
-------
water quality requirements of the stream. Surface waters are
classified as being either effluent limited or water quality
limited. The Eagle River and Gore Creek are both water quality
limited streams; they cannot meet BI stream standards without
more restrictive waste discharge limitations than the state
standards.
Ammonia toxicity to aquatic life is of primary concern in the
Eagle River and Gore Creek. EPA has suggested that a maximum
level of .02 mg/1 un-ionized ammonia should not be exceeded for
waters classified for fisheries use. Based on a .02 mg/1 limit,
and allowing for temperature, pH and streamflow dilution effects,
seasonal ammonia wasteload allocations were determined for Gore
Creek and the Eagle River in the 303 (e) Plan. Monthly
allocations were calculated in a second study prepared for Vail
Associates.
Colorado has not adopted an un-ionized ammonia standard, but one
has been recommended in the new proposed water quality standards.
Ammonia restrictions based upon the recommended limit have been
written into some of the latest discharge permits. The dis-
charge permit issued to the Upper Eagle Sanitation District
(UEVSD) for the Avon plant contains ammonia discharge limitations
based on the above report.
A-4
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APPENDIX B
Population Projections - Methodology and Definitions
Between 1960 and 1970, Eagle County population increased
from 4,680 to 7,500, a total increase of 60 percent.
Between 1970 and 1975, Eagle County population was es-
timated to have increased by 4,000 persons, a 53 percent
increase in five years or an 8 percent annual growth rate,
compounded yearly.
Each subarea was evaluated separately to establish the
pattern for growth in eastern Eagle County during the
next 20 years:
First, continued growth within the Vail area is
expected, and the nature and magnitude of that
growth is currently a source of concern and dis-
cussion. (Vail growth will be influenced by both
national and local politics, and by the economics
within the community as well as within the country
and abroad.) The skier capacity of Vail mountain
is expected to influence the rate of increase
significantly; as the mountain becomes saturated in
terms of design capacity, the market for new condominiums
should be reduced and the number of skiers may be
controlled through marketing or through artificial
limitations (e.g., parking, lift ticket reservations).
The second area of potential growth is the unincor-
porated portion of the Gore Valley, West Vail. This
area in whole or in part could be annexed to Vail
during the next 5 to 10-year period. The West Vail
Homeowners Association is composed of advocates both
for and against annexation. West Vail is currently
governed by County zoning and zoning exceptions*
have been granted for approximately 1200 units. As
parcels in West Vail are annexed and zone changes
are then granted by the Town of Vail, the current trend
has been to "downzone" this area.
Third, the expected development of the Beaver Creek
winter and summer recreation area by Vail Associates
at Avon will have profound, multiple effects upon
growth in the area during a 20-year period. The
development period of Beaver Creek may be of shorter
or greater duration than Vail. However, Benchmark
and Eagle-Vail planned subdivisions next to Beaver
Creek have already installed improvements and sold
*A zone exception is a preliminary plan approval granted
by the Eagle County Planning Commission.
A-5
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land, and these two developments can be expected to
receive a boost from Beaver Creek development. Thus
initial development in Avon could be at an accelerated
rate. Other parcels close to Beaver Creek ski area
could also be developed within a 20-year span (e.g.,
Nottingham Ranch). (Whenever the Beaver Creek/Avon
area is referred to in this study, the Beaver Creek,
Benchmark and Eagle-Vail developments are included.)
Fourth, Arrowhead is a second proposed winter and summer
recreation development in the Avon area which has a
shared boundary with Beaver Creek. Arrowhead's
development is considered to be more speculative than
Beaver Creek; however, future favorable economic and
market conditions could provide for this third ski
area development near Vail.
Fifth, Minturn is a small community which houses many
employees of the New Jersey Zinc Mine, as well as some
of the employees of the Vail area (an estimated 10 percent
of current Vail employees live in Minturn). Much of
the developable land around Minturn is owned by
Vail Associates. Future development possibilities for
the Minturn area are speculative and will depend upon:
(a) provisions for a demonstrated economic benefit for
Minturn residents, and/or (b) a change in the political
atmosphere. Minturn has recently downzoned within the
city limits to prevent dense development (e.g., motels)
from locating there.
Sixth, Redcliff is far removed from recreational
development pressure and will remain a small community.
Redcliff will probably attract only a few transient
construction workers employed elsewhere during the next
two decades.
Seventh, the rural parts of the County will not grow
appreciably due to the current restrictions on the use
of septic tanks, and current land use legislation which
protects mountain areas in particular.
The final decision as to methodology for population forecasting
was made after an examination of current methods being employed
in recreation areas and in areas of rapid growth in the
Rocky Mountain region. The proposed methodology was discussed
with Council of Government, County, State and local planners,
and with practitioners, consultants who previously
developed projections for Aspen, Steamboat Springs and
Craig, Colorado. The approach employed the use of assumptions
which resulted in a range of low, medium and high figures,
corresponding to the assumptions developed through interviews
with those who have local knowledge about changes likely
to occur during the next 15 years.
A-6
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Projects not mentioned in the population projections which
could impact the Gore Valley and Upper Eagle Valley were:
- expansion of the Eagle County airport
- development down Upper Eagle valley toward Edwards
and Wolcott
- the Iron Mountain Dam and the expansion of Homestake
Reservoir
- the Adam's Rib Ski Area proposed near Eagle
- expansion or depression of the U.S. ski industry
- expansion or depression of the demand for summer
resort areas in the mountains
- continuance of presidential visits
- the attraction of many industrial and manufacturing
concerns to the area
- location of educational and cultural facilities in Vail
- a depression in the national economy
- further delays in Beaver Creek development due to
financing or to environmental interests
- a local political atmosphere which is anti-growth
- an energy crisis which would affect travel, access
and mobility
Any major change in the given assumptions given in Tabular
form in the existing environment section of the EIS could be
monitored and measured against these background conditions.
Definitions and Ratios Utilized in the Population Estimates
The following definitions pertain to winter season unless
stated otherwise.
Peak Day; A peak day is defined as any average weekend
day during December and January. (Peak peak days
are weekend and holiday days at Christmas, New Years
and Washington's Birthday.) Source: Town of Vail
and Vail Associates.
Occupancy: The number of persons staying overnight in a
unit, calculated in terms of beds/unit. An average
of three beds per unit exists in Vail. Occupancy
rates in Vail were utilized in projecting occupancy
rates in the Beaver Creek and Arrowhead areas.
Winter average occupancy rates in Vail are: 80%
for those units which are under a central booking agency,
or a hotel or lodge (highly managed units) and 65%
for those units which are under the management of a
resident manager, owner or small agency. Peak occupancy
in Vail is 90 to 95 percent (all units); in Beaver
Creek and Arrowhead peak occupancy was estimated at
85% to account for the relative newness of the areas
and competition from Vail. Source: Johnson memoranda,
V.A., Town of Vail and Vail Resort Association.
A-7
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Average Visitor Population (overnight): Equal to the number
of units times average occupancy.
Peak Visitor Population (overnight): Equal to the number
of units times peak occupancy, 85% or 95%, depending
upon area.
Day or Short-Term Visitor Population; Present Vail Associates
estimates are that 3-4,000 out-of-town short-term visitor
skiers are in Vail on any winter weekend day. No data
exists for weekdays; however, weekday skier population
was estimated to be one-sixth of weekend visitors.
In estimating the winter average day visitor population
one-fourth the weekend day total was utilized for
totaling average daily population. Source: Vail
Associates automobile/parking lot surveys and CDM.
Permanent Population; Permanent population equals the number
of jobs times average number of persons per job (in
the Vail area 1.8 - 1.9 in the winter and 2.2 per job
in the summer). Source: The John Ryan Company, State
of Colorado Division of Employment. This ratio is low
due to the high number of singles and young people
attracted by seasonal recreational employment.
Peak Day Population; Equal to the peak day visitor population
(overnight and day or short-term) plus the permanent
population.
Average Daily Population: Equal to the average visitor
population (overnight and short-term) plus the permanent
population.
Day Skier to Visitor Skier Ratio; The day skier to visitor
skier ratio on weekends is estimated as 1.2. (One-third
of those on the mountain are day skiers, out-of-town
or locals.) In this report, the number of day skiers
has not been consistently recalculated to conform to
present ratios due to the following: as the number
of skiers on the mountain rises to the level at which
the peak day capacity is exceeded more often than 9%
of the time, the number of day skiers could decrease
or regulations or disincentives may be imposed (see
mountain capacity). Several alternatives exist to
Vail or Beaver Creek in Summit County — areas which
have declined recently in day skier population and
which could be expected to recapture a larger share
of the day skier market. Source: Vail Associates,
Colorado Ski Country, Forest Service. CDM ratios used
are the author's judgment.
A-8
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Skier Visitor to Non-Skiing Visitor Ratio; For every two
long term visitors who are on the mountain, there is
another visitor who is not skiing or a non-skier but
who is staying in lodging; an average of two-thirds
of all visitors are skiing daily. Source: Vail
Associates. Real estate and data analysis by COM.
Peak Skier Population: Equal to two-thirds of the over-
night visitor population, plus the total estimated
weekend day skier population. Source: Town of
Vail, V.A. data and analysis by COM.
Visitor Population to Employment Ratio: The visitor-to-
employment ratio in Vail averages 3 - 3.5 long-term
visitors (average) per job. Generally, these ratios
tend to be lower during the first few years of develop-
ment and may also reach a level where the incremental
gains in visitors do not generate new jobs. In Beaver
Creek, the Vail ratios were utilized; however, the
final visitor to job ratio is estimated at 4.8:1 due
to the conservative developer estimates of numbers
of jobs generated. (It should be kept in mind that
the basic and service job ratios may change; for
instance, if the Beaver Creek area has fewer condominium
accommodations and more lodge/motel units, then the
total number of service jobs would rise due to increases
in restaurants.) If the shopping center at Beaver Creek
is successful as a regional center, a higher number
of basic jobs per visitor will result. The ratios
are a combination of developer estimates, present ratios
and the author's judgment. Source: V.A., Ron Allred
and COM.
Mountain Design Capacity: (Design Day and Peak Day) Mountain
capacity is the number of skiers per day which can be
accommodated by the combination of ski lifts, ski trails
and access roads of an area (e.g., at Beaver Creek 13
lifts, 38 miles of trails and 15 miles of access roads
equal a design capacity of 7500). Design capacity is
related to vertical lift feet and mountain size.
A design day is defined as the 15th highest day on
the mountain, usually when design capacity.is reached.
When actual skier use exceeds the design capacity, a
peak period is reached. A peak day of 20% more than
design capacity is considered safe by the Forest Service
and is allowable for 15 total days per 156 day season
(9.6%). As stated in the Forest Service use permit,
Beaver Creek may exceed 7,500, or design day, 15 days
of the season (up to 9,000). If the design day is
exceeded more than 15 days per season, then V.A. and
the Forest Service will "work to establish a use
control system." Source: V.A. draft EAR and Forest
Service interviews.
A-9
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Market Absorption Rate (Real Estate)^; The market absorption
rate for condominium and second home sales in units
per year. The current rate in Vail has been 200 - 300
units per year for the past 4 to 5 years. (When lodge
units are included, Vail has experienced an average
total absorption rate of 400 units per year in 14 years
of development.) This rate is dependent upon the economy
and national recreational demand trends. Source:
V.A. and real estate interviews.
Summer Employment (Vail); Equal to approximately 70 percent
of winter employment.
Summer Population (Vail — permanent): Equal to approximately
87 percent of winter population.
Summer Visitor Population (Vail): The John Ryan Company
estimates an average of 1100 visitors per day, but
the summer peaks and valleys of visitor population
are much wider than the winter. (Conventions usually
come in late summer/early fall; May and October are
months when nearly everyone leaves.) An analysis of
sales tax returns, summer occupancy rates and bus
ridership suggests that the summer visitor population
is 30 - 40% that of winter, depending upon month.
Population Allocations; An estimated 80 percent of Vail's
winter employees currently live in the Vail area
(50 percent in Vail and 30 percent in West Vail) and
20 percent live in Minturn, Avon, Eagle, Gypsum and
rural areas. There will be employee housing (an estimated
1200 units) provided in the Beaver Creek/Avon area
at full development. The employee exchange between
Vail and West Vail employees living in Beaver Creek
and Beaver Creek employees living in Vail will probably
offset one another. Therefore, 85 percent of Vail
and Beaver Creek permanent populations were allocated
to remain at their place of employment, 10 percent
were allocated to Minturn, 5 percent to communities
outside the boundaries of the study area (80 percent
of Arrowhead employees were allocated to that base
area). Source: The John Ryan Company, Town of Vail,
and Colorado Division of Employment Security; data
analysis by COM. (Employee housing data supplied
by Benchmark, Vail Associates and Eagle-Vail; Arrowhead
Development would add another 400 employee units to
the area.)
Vail and the Gore Valley
Vail Village, developed as the business core, also supports
high density condominium and lodge development. Pressure
A-10
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from businesses -iesiring zoning conversions j.n the core is
being placed on the town council and planning commission.
Many of the buildings built in the 1960's do not conform
to present building codes. The renovation and renewal of
older buildings could be economically dependent upon zoning
exceptions. Higher densities might be permitted to encourage
needed renewal or upgrading given a demonstrated economic
need.
The market absorption rate for new units in Vail has been
an average 200 - 300 units per year for the Vail area (past
5 years). An oversupply between 1973 - 1975 was caused by
several factors: in 1973 an ordinance was proposed which
would have downzoned all developments causing some developers
to proceed ahead of schedule; the second-home market fell
in 1972-73 due to the recession and new tax laws.
The second Vail commercial core is at Lionshead. This area
is presently evaluated as under-utilized in terms of total
occupancy due to particularly low summer use, and to the
high number of units which are privately owned and not
available as high occupancy rentals. A second factor may
be the lack of successful marketing of this area for
conferences.
The Bighorn area in east Vail, recently annexed, is an area
of low density, with many large single family homes, duplexes,
and some multi-family condos. Densities are expected to
remain low due to a more severe climate, less access, and
topography and avalanche hazards.
The West Vail area, which is unincorporated,is an area
with many undeveloped parcels, although there now exist
a number of large condominium developments, single family
and duplex type homes. In December, 1975, the Lionsridge
area of West Vail was annexed to Vail and downzoned.
Currently, the County has voted for zone changes to permit
at least 1200 units to be built in the West Vail area
based on preliminary plat approval. If West Vail is annexed,
in part or as a whole, downzoning is expected to occur.
In addition, as peak mountain capacity is reached on more
than 15 season days (that which is allowable under the
Forest Service permit under which ski areas operate), two
questions will be addressed:
1. How to market the low season, November through
mid-December and April for more timely and
efficient use of the mountain.
2. Will a reservation system for ski-lift tickets
be necessary in order to prevent the saturation
of the mountain? (The Forest Service is committed
to dealing with this problem with the developer,
Vail Associates, as soon as mountain design day
capacity is exceeded more than 15 season days.)
A-ll
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The condominium market itself may regulate Vail growth
and prevent the kind of overbuilding which would promote
skier regulation. One assumption that was fairly consistent
in all of the Vail growth projections — no high growth rates
were predicted for the Vail area; somewhere between 1,200 -
3,500 new units were projected to be built within the next
15 to 20 years.
The Beaver Creek/Avon Area
Currently, the Avon area is sparsely populated by an
estimated 600 residents, many of whom work in Vail. The
area has been the subject of many recent studies due to
the proposed Beaver Creek ski area development by Vail
Associates. Subdivisions exist with improvements and
some buildings. These developments would receive a growth
impetus when Beaver Creek is developed. Benchmark has begun
construction of a regional shopping center; a bowling alley
and theater are planned for this summer. Eagle-Vail has
built a golf course and both have already constructed units.
Each growth profile for the Beaver Creek/Avon area included
the development of Beaver Creek as a ski area due to recent
state and Forest Service approvals. The start-up development
year and final projected number of units vary as well as
the anticipated annual rates of growth.
The success of Beaver Creek as a ski area .is dependent
upon continued expansion of recreational skiing demand,
especially destination skier demand. Vail has averaged
an annual 18 percent increase in demand during the past
5-10 years, which is only partially related to mountain
expansion. During a period of recession in the U.S., and
during an energy crisis, the demand for destination skiing
has risen steadily in Colorado and the West. Part of this
increase may be attributable to skiers who changed from
vacationing at European ski resorts to ski areas in the U.S.
after dollar devaluation; however, some of the increase
is due to an influx of new skiers as skiing becomes accessible
to a larger segment of the population. (Both these condi-
tions could be subject to peaking or declining.) Some
market surveys for the future demand exist. Both positive
and negative growth has been projected; therefore, the
future is speculative. The current attitude of the state,
the investment houses and the Forest Service is one of
caution as compared to the attitude of 10 years ago. A
use permit has been granted by the Forest Service for
the Beaver Creek Ski area; therefore population projections
are made for the Beaver Creek/Avon area based upon ski area
development.
A-12
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Beaver Creek/Avon development will influence the rate of
growth in Vail, and the existence of Vail and the Vail
growth experience are expected to influence the development
of Beaver Creek. The present situation in Vail, the over-
supply of condominiums coupled with an "unbalanced mix"
of condo-apartments to motel and lodge space, may sig-
nificantly affect development in Beaver Creek. The
development of lodges and motels could be more desirable
near the beginning stages of the Beaver Creek with base
area condo development following at a slower pace. In
Benchmark and Eagle-Vail, far more condominiums than lodge
unit development is planned. These development plans could
change as the most profitable markets emerge. Although the
Beaver Creek Ski area will begin at a more accelerated pace
than Vail, due in part to the growth which has already occurred
in the area, the growth curve is expected to flatten out over
a longer period of time, hopefully avoiding an oversupply of
units.*
Arrowhead
For the purpose of population projections, Arrowhead has
been considered separately from the Beaver Creek/Avon pro-
jections. While both Benchmark and Eagle-Vail rely upon
Beaver Creek as an economic determinant in terms of skiing, thi
master plan for the Arrowhead area includes a ski development
with a 4800 skier design capacity (per day) a golf course in
each phase (a total of two) and equestrian trails and stable.
At this time, many people consider Arrowhead much more
speculative than Beaver Creek. The developers themselves
insist that development will begin very soon. For these
reasons, the suggestion to consider Arrowhead separately was
followed.
Arrowhead has been planned in two phases: phase 1 will have
2700 units (965 employee, 1275 high occupancy and 460 low
occupancy units); phase 2 is platted for 600 units, 180 employee,
300 high occupancy and 120 low occupancy units.
Minturn
Minturn is a small mining community 1.7 miles south of Dowds
Junction and 7 miles southwest of Vail. Today the Minturn
Valley is populated by some 1500 persons although less than
half live in the town. Many of the residents work at the
New Jersey Zinc Mine; others, the more recent residents, work
*The development of Meadow Mountain at Minturn as a beginner
area was not considered because of V.A.'s stated preference
to make a land trade with the Forest Service.
A-13
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in Vail (an estimated 10 percent of Vail employees live in
Minturn). Sixty to seventy-five percent of the Minturn area
population is Spanish speaking.
Between 1900 and 1930 Minturn population stabilized at
approximately 400 persons. By 1940, the population grew to
596, and between 1940 and 1950 another 165 individuals were
added to the census. During the 10 years from 1960 to 1970,
another 44 individuals moved to the community. The Valley,
however, grew by more than 100 percent, from a few hundred to
800 or more (figures for the Valley are somewhat indefinite
due to the aggregation of the rural population). It is
estimated that during the past 5 years Minturn has added 260
more people totaling 960, a 7.2 percent average annual growth
rate for 5 years.
The population in Minturn is expected to grow when Beaver
Creek is developed due to the immigration of employees. .
Although Vail Associates (V.A.) is committed to local recruit-
ment, training and local employment where possible, many
newcomers will be seasonal employees and not dependent upon
year-round employment.
Minturn population projections reflect the influence of
both Vail and Beaver Creek. The future of Minturn is more
certain than either recreation area. Possible influences,
some of which are currently having an effect upon Minturn are:
local concern over rapid growth (downzoning has recently
occurred), possible closure of the New Jersey Zinc Mine
(which has been discussed for the past 10 years), annexation
policies, acceptance of V.A. employment by locals and employee
housing demands from Beaver Creek. The growth assumptions for
Minturn were based upon present trends; however, one factor
which was impossible to assess was the present and evolving
political attitude.
Table 4 on the following page gives a breakdown of permanent
and transient population for Minturn based upon the assump-
tions presented in the population section of the EIS.
Red Cliff
The community of Red Cliff is approximately 16 miles southwest
of Vail and 9 miles south of Minturn. This area is one of
sparse population; about 650 residents live in Red Cliff.
Red Cliff began as a mining community and today many of the
residents work for the New Jersey Zinc Mine. (The population
is 53 percent minority (Spanish surname) with approximately
80% of the surrounding population classified as minority.)
Since 1910, Red Cliff population has fluctuated. Between
1910 and 1940 Red Cliff grew from 240 to 715 population,
A-14
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declining to 585 by 1960. Since I960, Red Cliff has grown
to 621 residents which represents an average yearly increase
of only .59 percent. The population has not been significantly
influenced by Vail growth.
Red Cliff is not expected to attract many of the employees
of the Vail area because of its relative isolation. Con-
struction workers may elect to live this distance from Beaver
Creek during the initial development stages. This will depend
in part upon the provision of inexpensive housing near the
project site. If Beaver Creek or Vail growth were to affect
Red Cliff, the population impact would be minimal, since
commuting time is similar to communities with more amenities.
Another possible growth influence would be the Iron Mountain
Dam project which is part of Phase II of the Homestake Project.
This project would serve the City of Aurora and Colorado Spring-
Project construction is projected to begin between 1980-83.
Crews would be as large as 300 men during summer peaks. Only
two growth projections were made for Red Cliff. The area
could gain or lose population depending, as Minturn, upon a
possible closing of the New Jersey Zinc Mine. Since Minturn' t
population is not broken into visitor/permanent/transient
groups, no detailed breakdown is presented in this appendix,
figures are contained in the existing environment section of
this report.
A-15
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APPENDIX C
AIR QUALITY
Assumptions and Procedures
This appendicized data gives the background for some of the
assumptions found in the body of the report for fuel consumption,
fireplaces, vehicle use, and meteorology. These data relate to
emissions and worst case assumptions.
Fuel Consumption
Data regarding fuel consumption came from several sources. The
1975, rather than 1974, data were utilized, although fuel con-
sumption was two percent less in 1975. Fuel consumption by air-
shed was calculated by using average household use times number
of households. Daily use (winter) was calculated as 70 percent
of total use divided by the number of days from November to April
(period when 70 percent consumption occurs). Fuel consumption
by airshed for 1975 is shown in Table A-2. The emission rates
used are in the body of this report. The assumed worst case
condition, for space heating, was -5° F, when most furnaces
would be in continuous or 90 percent use. Future planned
developments intend to utilize all electric units; no polluting
fuels will be used. Future increases in household fuel use,
by airshed, was deemed nominal, and calculated only in areas
presently served.
Wood Burning Fireplaces
Fireplace emission factors obtained from an EPA sponsored study
of residential fireplace emissions in Seattle, Washington, were
the only data available. Tests using pine were utilized for
particulate emission factors, and those using Douglas Fir were
utilized for CO factors. The CO factors were run using the box
model and were found to be too high to be valid — thus CO em-
missions for fireplaces were not calculated for future years for
the study area.
Calculations for numbers of existing and new fireplace units were
A-16
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I
I-1
^1
TABLE A-2
1975 FUEL CONSUMPTION
AIRSHED
Bighorn
East Vail
Vail Village
West Vail
Minturn
Dowd-Avon
Beaver Creek
Avon
Avon-Edwards
NATURAL GAS
(10^ cubic feet)
46.5
15.5
524.4
82.5
32.5
-
-
-
_
LP GAS
(103 gallons;
8.8
6.7
60.7
23.8
30.0
38.0
-
200.0
38.0
SOURCES: Public Service Company, Williams Energy Company
Daily Natural Gas Consumption = (number of natural gas customers)
X (22.5 ft. /dwelling unit/degree-day) X (70 degree-days)
published APTD-1135, 1973
Each degree below 65 F represents one degrei day,
70 degree days
-------
I
developed using the present and projected number of units, by
type and by airshed, in the study area. This data was developed
in part, during the population projections analysis. Dwelling
units were designated single family, multifamily, or lodge units,
either according to zoning (Vail) or developer preliminary plats
(Dowds-Avon) or present ratios (Minturn). Each single family
duplex or multifamily unit was assumed to have one fireplace.
One fireplace per 25 lodge units was assumed. Present and pro-
jected numbers of units and fireplaces are given in Table A-3.
Population and dwelling units were converted into growth fac-
tors in future years by airshed. These growth factors were
utilized to estimate future emission rates whenever no other
sources of data were available, as in natural and LP gas con-
sumption in areas presently served.
Vehicles - Mobile Sources
Traffic data and calculations of total vehicle miles travelled
(VMT's) and average daily traffic (ADT) are caijxments of the
traffic emissions data. Peak day traffic volumes were used to
represent a worst case. Peak day emissions from highway sources
were converted to hourly emissions using hourly traffic break-
down for the area. Average daily traffic figures for freeways
and arterials are given in Table A-4 on the following page. These
figures represent number of miles of road by type, in each airshed,
multiplied by average daily traffic and. typical" peak day traffic
volumes. These figures were used in developing emission rates.
Traffic for a typical peak day is 1.15 ADT for freeways and
arterials. Local peak traffic was obtained from ADT using
average to peak population ratios. Average traffic counts
were taken by Town of Vail and The John Ryan Company- Future
estimates for freeway and arterial traffic in the Upper Eagle
Valley came from the Colorado Division of Highways. Hourly
traffic estimates were used to estimate percent of total
emissions to enter, by hour. These percentages are given in
Table A-5.
These assumptions when combined with the emission ratios
given in the body of the report, resulted in the current and
projected emission rates given in Table A-6.
Meteorology
Worst case conditions for wind direction and speed were obtained
from Vail mechanical weather station data. Selected days with
definite downslope and upslope wind patterns and apparently
little large scale influence were analyzed. Hourly wind speeds
and directions most conducive to pollutant buildup were averaged
A-18
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TABLF A-3
DWELLINC UNIT AND FIREPLACE PROJECTIONS
AlfHlu'll
Blphorn
F.nst Vail
V.il 1 VII lap.e
West Vail
Minturn
Uowd-Avon
Beaver Creek
Avon
Aviin-Fdwards
111 Thorn
t.nst Vail
Vn1 1 Village-
West Vail
N i n t u rn
Dowd-Avon
hr;ivi>r ( rrek
1 i n
Avrn-F.dw.irds
Klfhorn
K.-i'.t V;il 1
V., II VII l.ip,.-
West Vail
Minturn
iJOwd-Avon
Beaver Creek
Avon
Avon-Fdwards
Btjjhorn
F.ast Vail
Veil Village
West Vail
Minturn
Dowd-Avon
Beaver Creek.
Avon
Avon-Edwards
SlnK]r Multi-
F/imllj; Dun IPX l-'nmllv^ Ln<\Kf
1975
59 64 277 24
40 182 100
92 14 1665 1136
63 195 834 48
226 125
75
I'lHO
81 HH 'W? 14
42 191 105
97 15 1743 1187
83 259 1109 64
289 159
22 SB 1P7
72 180 ?90
41 41: 171
1985
107 ill ,-.'i , ,
44 149 lin
102 16 lH2n i?3u
104 323 1383 78
315 174
60 240 512
197 493 790
119 112E 467
100 440
1990
123 133 578 51
46 208 114
106 17 1898 1291
125 387 1658 95
330 182
81 322 686
264 661 1061
159 1514 626
200 880
A-19
To t u 1
ntln-r Units
424
322
2907
1140
351
25 100
230 230
58S
338
1042
1515
448
297
542
4? *69
/ 1 i
1r;1
)l 77
1890
489
812
115 1480
1829
540
885
368
3312
2265
512
1089
1986
154 2453
1080
Torn)
Fl rop] nces
401
226
181*
1^94
231
75
'.53
23*
1901
1454
2%
207
264
'16 '
'•'i .
241!
J98h
1814
322
812
722
1266
118
837
559
2073
2174
338
1089
968
1699
236
-------
TABLE A-4
AVERAGE DAILY TRAFFIC1
Airshed
Bighorn
East Vail
Vail Village
West Vail
Minturn
Dowd-Avon
Beaver Creek
Avon
Avon-Edwards
1975
-
7167
7167
7502
-
4867
-
4867
4758
1980
Freewa
9250
9250
9250
9762
-
7202
-
7202
6550
1985
y.
10,725
10,725
10,725
12,022
-
9,536
-
9,536
8,341
1990
12,200
12,200
12,200
14.282
-
11,871
-
11,871
10,132
Miles of
Road
2.0
2.5
2.5
2.9
0.0
2.7
0.0
2.2
2.7
Arterial
Bighorn
East Vail
Vail Village
West Vail
Minturn
Dowd-Avon
Beaver Creek
Avon
Avon-Edwards
Bighorn
East Vail
Vail Village
West Vail
Minturn
Dowd-Avon
Beaver Creek
Avon
Avon Edwards
7167
1500
4328
4328
3536
1306
1106
640
850
650
5000
2280
1000
280
-
645
_
1705
1705
4921
5700
3966
1936
1084
3586
790
Local
1243
739
5685
2592
1250
713
1141
2836
_
2,214
1,835
5,295
7,336
4,396
2,566
2,623
6,066
940
1,614
795
6,117
3,336
1,299
1,725
2,761
6,865
1,080
2,498
1,780
5,136
8,136
4,826
3,196
3,751
8,546
1,090
1,821
800
6,000
3,700
1,300
2,483
3,972
9,876
2,192
2.0
2.0
3.5
3.0
2.3
2.7
2.0
2.8
3.3
1.0
1.0
3.0
2.0
2.0
2.0
2.0
2.0
2.0
Traffic for a typical peak day is 1.15 ADT for freeway and
arterial traffic. Local peak traffic was obtained from ADT
with average/peak population ratios.
SOURCE: Marlatt and Associates, 1976, Colorado Department
of Highways and Town of Vail
A-20
-------
TABLE A-5
HOURLY TRAFFIC BREAKDOWN
Time
Midnight
1
2
3
4
5
6
7
8
9
10
11
Noon
1
2
3
4
5
6
7
8
9
10
11
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- Noon
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- Midnight
Percentage of Average
Daily Traffic
1.7
1.0
0.9
0.5
0.5
0.5
1.3
2.6
5.2
6.5
6.0
6.1
7.0
7.2
6.8
8.3
9.1
7.4
5.6
4.1
3.2
2.9
2.7
1.8
SOURCE: Marlatt and Gelinas, 1975
A-21
-------
TABLE A-6
Year
1975
1980
1985
1990
Airshed
Bighorn
East Vail
Vail Village
West Vail
Mlnturn
Dowd-Avon
Beaver Creek
Avon
Avon-Edwards
Bighorn
East Val]
Vail Village
West Vail
Hinturn
Dowd-Avon
Beaver Creek
Avon
Avon-Kdwnrds
Bighorn
East V.ilj
Vail Village
West Vail
Minturn
Doud-Avon
Beaver Creek.
Avon
Avon-F.dwards
Bighorn
East Vail
Vail Village
West Vail
Minturn
Doud-Avon
Beaver Creek
Avon
Avon- Edwards
Total Suspended
Wood
Burning
(grams
8.2
4.6
37.3
22.5
4.7
1.6
-
11.4
4.9
39.1
29.9
6.1
6.1
5.4
9.5
15.1
7.3
65.2
38.8
1C.O
16.7
30.4
37.5
11.1
18.2
7.6
67.9
46.5
10.5
22.3
40.7
50.3
22.2
Part Iculates
Space
Heating
per second)
.042
.015
.470
.075
.032
.003
-
.018
.003
.057
.015
.494
.099
.040
.009
.053
.003
.072
.016
.512
.124
.044
.026
.144
.003
.087
.017
.534
.150
.046
.035
-
.193
.006
Traffic
Average
.111
.157
.381
.294
.071
.123
-
.109
.108
.168
.197
.431
.372
.081
.189
.034
.230
.146
.190
.226
.474
.463
.089
.262
.081
.382
.200
.227
.252
.501
.536
.096
.330
.113
.507
.253
Trnins
-
-
.079
.079
-
."79
.079
-
.070
.070
-
.079
.070
.079
.079
-
.079
.079
-
-
-
-
.079
.079
-
.079
.079
A-22
-------
to obtain a reasonable set of "worst case conditions." Similar
conditions are likely to occur once and possibly several times
during the winter period in the study area. These assumptions
are qiven in Table A-7 on the following page.
A-23
-------
TABLE A-7
Time
METEOROLOGICAL ASSUMPTIONS.
Wind Speed
Meters/sec. (Miles/hr.)
Wind Direction
I
10
Midnight - 1
1
2
3
4
5
6
7
8
9
10
11
Noon
1
2
3
4
5
6
7
8
9
10
11
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- Noon
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- Midnight
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
1.2
2.0
2.5
2.5
2.0
1.2
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
(1.34)
(1.34)
(1.34)
(1.34)
(1.34)
(1.34)
(1.34)
(1.34)
(1.34)
(1.34)
(2.68)
(4.47)
(5.59)
(5.59)
(4.47)
(2.68)
(1.34)
(1.34)
(1.34)
(1.34)
(1.34)
(1.34)
(1.34)
(1.34)
Downslope
Downslope
Downslope
Downslope
Downslope
Downslope
Downslope
Downslope
Downslope
Downslope
Upslope
Upslope
Upslope
Upslope
Upslope
Upslope
Downslope
Downslope
Downslope
Downslope
Downslope
Downslope
Downslope
Downslope
SOURCE: Vail Meteorological Station data/average adapted for worst case conditions.
-------
APPENDIX D
List, By Community, of Common and Scientific Names of Plant Species Expected To
Occur in the Upper Eagle Valley Sanitation District, Eagle County, Colorado.
ASPEN COMMUNITY
Trees
Aspen
Douglas-fir
Engelmann spruce
Lodgepole pine
Shrubs
Herbs
Chokecherry
Currant
Serviceberry
Wild rose
Snowberry
Arnica
Aster
Brome grass
Colorado columbine
Common lupine
Daisy
Dandelion
Elk sedge
Geranium
Meadowrue
Mountain-lover
Oregon-grape
Peavine
Tall larkspur
Thimble-berry
Thistle
Vetch
Wild-rye
Wild strawberry
Yarrow
Yellow paintbrush
Populus tremuloides
Pseudotsuga menziesii
Picea engelmannii
Pinus contorta
Prunus virginiana
Ribes sp.
Amelanchier a 1nifo1ia
Rosa woodsii
Symphoricarpos oreophilus
Arnica cordifolia
Aster engelmannii
Bromus carinatus
Aquilegia caerulea
Lupinus argenteus
Erigeron eximius
Taraxacum officinale
Carex geyeri
Geranium fremontii
Thalictrum fendleri
Pachystima myrsinites
Mahonia repens
Lathyrus leucanthus
Delphinium occidentale
Rubus parviflorus
Cirsium sp.
V i c i a americana
Elymus glaucus
Fragaria oval is
Achillea lanulosa
Castilleja sulphurea
MIXED EVERGREEN COMMUNITY
Trees
Aspen
Engelmann spruce
Lodgepole pine
Subalpine fir
Populus tremuloides
Picea engelmannii
Pinus contorta
Abies lasiocarpa
A-25
-------
APPENDIX D (Continued)
Shrubs
"Buffalo-berry
Bush honeysuckle
Kinnikinnick
Serviceberry
Thimble-berry
Wild rose
Willow
Herbs
Arnica
Aster
Bedstraw
Dandelion
Fireweed
Hawkweed
Lily
Lupine
Meadow rue
Mountain-lover
Myrtle blueberry
Oregon-grape
Peavine
Subalpine daisy
Sweet cicely
Twin flower
Vetch
Wild Strawberry
Wintergreen
Shepherdia canadensis
Lonicera involucrata
Arctostaphylos uva-ursi
Amelanchier alnifolia
Rubus parviflorus
Rosa woodsii
Salix
sp.
Arnica cordifolia
Aster enge1manm~
Galium triflorum
Taraxacum officinale
Epilobium angustifoTium
Hieracium albiflorum
Disporum trachycarpum
Lupinus argenteus
Thalictrum fendleri
Pachystima myrsinites
Vaccinium myrtillus
Mahonia repens
Lathyrus leucanthus
Erigeron eximius
Osmorhiza depauperata
Linnaea boreal is
Vicia americana
Fragaria oval is
Pyrola virens
SPRUCE-FIR COMMUNITY
Trees
Aspen
Engelmann spruce
Lodgepole pine
Subalpine fir
Shrubs
Buffalo-berry
Bush honeysuckle
Currant
Thimble-berry
Willow
Herbs
Arnica
Avalanche lily
Bedstraw
Populus tremu1oid.es
Picea engelmannii
Pinus contorta
Abies lasiocarpa
Shepherdia canadensis
Lonicera involucrata
Ribes sp.
Rubus parviflorus
Salix sp.
Arnica cordifolia
Erythronium grandiflorum
Galium triflorum
A-26
-------
APPENDIX D (continued)
Herbs (continued)
Bluegrass Ppj. sp.
Elk sedge Carex geyeri
Fireweed Epilobium angustifolium
Globeflower Trollius laxus
Lupine Lupinus argenteus
Mountain-lover Pachystima myrsinites
Myrtle blueberry Vaccinium myrtillus
Oregon-grape Mahonia repens
Parry lousewort Pedicularis parryi
Porter lovage Ligusticum porteri
Subalpine daisy Erigeron eximius
Sweet cicely Osmorhiza depauperata
Vetch Vicia americana
Wild strawberry Fragaria oval is
Wintergreen Pyrola virens
MEADOW COMMUNITY
Shrubs
Willow Salix sp.
Herbs
Bluegrass Poa agassizensis
Cow parsnip Heracleum lanatum
Dandelion Taraxacum officinale
False hellebore Veratrum tenuipetalum
Fescue Festuca thurberi
Orchard grass Dactyl is glomerata
Plantain Plantago lanceolata
Rush Juncus sp.
Salsify Tragopogon pratensis
Sedge Carex sp.
Sunflower Gymnolomia multiflora
Tarweed Madia glomerata
Thistle Cirsium arvense
Timothy Phleum pratense
Yarrow Achillea lanulosa
MOUNTAIN BRUSH COMMUNITY
Shrubs
Big sagebrush Artemisia tridentata
Bitterbrush Purshia tridentata
Buffalo-berry Shepherdia canadensis
Chokecherry Prunus virginiana
Mountain mahogany Cercocarpus montanus
Rabbitbrush Chrysothamnus nauseosus
A-27
-------
APPENDIX D (continued)
Shrubs (continued)
Serviceberry
Snowberry
Herbs
Bluegrass
Indian ricegrass
Lupine
Needle-and-thread grass
Paintbrush
Peavine
Scarlet gilia
Sedge
Showy daisy
Sulphur-flower
Sunflower
Vetch
Wheatgrass
Yarrow
Amelanchier alnifolia
Symphoricarpos oreophilus
Poa nemoralis
Oryzopsis hymenoides
Lupinus'argenteus
Stipa comata
Castilleja flava
Lathyrus leucanthus
Ipomopsis aggregata
Carex sp.
Erigeron speciosus
Eriogonutn umbellatum
Gymnolomia multiflora
Vicia americana
Agropyron sp.
Achillea lanulosa
RIPARIAN COMMUNITY
Trees
Aspen
Colorado blue spruce
Douglas-fir
Engelmann spruce
Narrowleaf cottonwood
Rocky Mountain juniper
Western red birch
Populus tremuloides
Picea pungens
Pseudotsuga menziesii
Picea engelmannii
Populus angustifolia
Juniperus scopulorum
Betula fontinalis
Shrubs
"Alder
Chokecherry
Dogwood
Rocky Mountain maple
Willow
Herbs
Bedstraw
Bittercress
Bluebell
Bluegrass
Brome
Clover
Cowbane
Cow parsnip
Dandelion
False hellebore
Alnus tenuifolia
Prunus virginiana
Cornus stolonifera
Acer glabrum
Salix sp.
Galiurn trifolium
Cardamine cordifolia
Mertensia ciliata
Poa sp.
Bromus lanatipes
Trifolium sp.
Oxypolis fendleri
Heracleum lanatum
Taraxacum officinale
Veratrum tenuipetal urn
A-28
-------
APPENDIX D (continued)
Herbs (continued)
Fescue Festuca thurberi
Geranium Geranium fremonti i
Horsetail Equisetum arvense
Manna grass Glyceria striata
Marsh marigold Caltha leptosepela
Meadowrue Thalictrum sparsiflorum
Monkshood Aeoniturn columbianum
Northern bedstraw Ga1i urn boreale
Orchard grass Dactyl is glomerata
Sedge Carex sp.
Swamp wintergreen Pyrola asarifolia
Sweet cicely Osmorhiza depauperata
Timothy Phleum pratense
Three-awn grass Agrostis gigantea
Wild-rye Elymus glaucus
Wild strawberry Fragaria oval is
Sources: Harrington (1964), Weber (1972)
A-29
-------
APPENDIX F
List of Common and Scientific Names of Terrestrial Wildlife Species (Except
Birds) Expected to Occur In or Near the Upper Eagle Valley Sanitation District,
Eagle County, Colorado.
Common Name
AMPHIBIANS
Ambystomids
Tiger Salamander
True Frogs
Leopard Frog
Scientific Name
Ambystomidae
Ambystoma tiqrinum
Ranidae
Rana pipiens
REPTILES
Iguanids
Sagebrush Lizard
Eastern Fence Lizard
Colubrids
Western Terrestrial Garter
Snake
Gopher Snake
Iguanidae
Sceloporus graciosus
Sceloporus undulatus
Colubridae
Thamnophis elegans
Pituophis melanoleucus
MAMMALS
Shrews
Vagrant Shrew
Vespertilionid Bats
Little Brown Myotis
Long-eared Myotis
Long-legged Myotis
Townsend's Big-eared Bat
Pikas
Pika
Hares and Rabbits
NuttalVs Cottontail
Snowshoe Hare
White-tailed Jack Rabbit
Squirrels
Least Chipmunk
Colorado Chipmunk
Soricidae
Sorex vagrans
Vespertilionidae
Myotis lucifugus
Myotis evotis
Myotis volans
Plecotus townsendii
Ochotonidae
Ochotona princeps
Leporidae
Sylvilagus nuttallii
Lepus americanus
Lepus townsendii
Sciuridae
Eutamias minimus
Eutamias quadrivittatus
A-30
-------
APPENDIX E(continued)
Common Name
MAMMALS (Continued)
Squirrels (Continued)
Uinta Chipmunk
Yellow-bellied Marmot
Richardson's Ground Squirrel
Golden-mantled Ground Squirrel
White-tailed Prairie Dog
Red Squirrel
Pocket Gopher
Northern Pocket Gopher
Beavers
Beaver
New World Rats and Mice
Deer Mouse
Bushy-tailed Woodrat
Montane Vole
Long-tailed Vole
Southern Red-backed Vole
Muskrat
Jumping Mice
Western Jumping Mouse
New World Porcupines
Porcupine
Can ids
Coyote
Red Fox
Bears
Black Bear
Procyonids
Ringtail
Raccoon
Mustelids
Marten
Ermine
Long-tailed Weasel
Mink
Badger
Western Spotted Skunk
Striped Skunk
Scientific Name
Eutamias umbrinus
Marmota flaviventris
Spermophilus richardsonii
Spermophilus lateralis
Cynomys leucurus
Tamiasciurus hudsonicus
Geomyidae
Thomomys talpoides
Castoridae
Castor canadensis
Cricetidae
Peromyscus maniculatus
Neotoma cinerea
Microtus montanus
Microtus longicaudus
Clethrionomys gapperi
Ondatra zibethicus
Zapodidae
Zapus princeps
Erethizontidae
Erethizon dorsatum
Canidae
Canis latrans
Vulpes vulpes
Ursidae
Ursus americanus
Procyonidae
Bassariscus astutus
Procyon lotor
Mustelidae
Martes
americana
Mustela erminea
Mustela frenata
Mustela vison
Taxidea taxus
Spilogale gracilis
Mephitis mephitis
A-31
-------
APPENDIX E (continued)
Common Name Scientific Name
MAMMALS (Continued)
Cats Felidae
Mountain Lion Pel is concolor
Lynx Pel is lynx
Bobcat Pel is rufus
Cervids Cervidae
Wapiti or Elk Cervus elaphus
Mule Deer Odocoileus hemionus
Sources: Armstrong (1972), Colorado Division of Wildlife (1975),
Jones et al. (1975), and Stebbins (1966)
A-32
-------
APPENDIX F
List of Common and Scientific
Upper Eagle Valley Sanitation
Names of Birds Expected
District, Eagle County,
to Occur In
Colorado.
or Near the
Code^
Mp
Mp
Me
MSc
Mp
MSc
Sp
Mp
MSp
Mp
Me
Mp
Yc
Mp
Mp
Yc
Mp
Mp
Mp
Me
Sc
Mp
Mp
Mp
Mp
We
Mp
Mp
Me
Mp
Yc
Common Name
Loons
Common Loon
Grebes
Eared Grebe
Western Grebe
Pied-billed Grebe
Cormorants
Double-crested Cormorant
Herons
Great Blue Heron
Little Blue Heron
Snowy Egret
Ibises
White-faced Ibis
Swans, Geese and Ducks
Whistling Swan
Canada Goose
Snow Goose
Mallard
Gadwall
Pintail
American Green-winged Teal
Blue-winged Teal
Cinnamon Teal
American Widgeon
Shoveler
Wood Duck
Redhead
Ring-necked Duck
Canvasback
Lesser Scaup
Common Goldeneye
Barrow's Goldeneye
Bufflehead
Ruddy Duck
Hooded Merganser
Common Merganser
Scientific Name
Gaviidae
Gavia immer
Podicipedidae
Podiceps nigricolis
Aechmophorus occidental is
Podilymbus podiceps
Phalacrocroracidae
Phalacrocorax auritus
Ardeidae
Ardea herodias
Florida caerulea
Egretta thula
Threskiornithidae
Plegadis chihi
Anatidae
01 or columbianus
Branta canadensis
Chen caerulescens
Anas platyrhynchos
Anas strepera
Anas acuta
Anas crecca
Anas discors
Anas cyanoptera
Anas americana
Anas clypeata
Aix sponsa
Aythya americana
Aythya collaris
Aythya valisineria
Aythya affinis
Bucephala clangula
Bucephala islandica
Bucephala albeola
Oxyura jamaicensis
Lophodytes cucullatus
Mergus merganser
A-33
-------
APPENDIX F(continued)
Code* Common Name
American Vultures
Sc Turkey Vulture
Hawks and Harriers
Yc Goshawk
Yc Sharp-shinned Hawk
Yc Cooper's Hawk
Yc Red-tailed Hawk
SMc Swainson's Hawk
We Rough-legged Hawk
Sp Ferruginous Hawk
Yc Golden Eagle
We Bald Eagle
Yc Marsh Hawk
Ospreys
St Osprey
Falcons
Mp Gyrfalcon
Yp Prairie Falcon
YSe Peregrine Falcon
Wp Merlin
Yc American Kestrel
Grouse
Yc Blue Grouse
Turkeys
Yp Wild Turkey
Cranes
Mp Greater Sandhill Crane
Rails and Coots
Sp Sora
Sc American Coot
Plovers
Yc Kill deer
Snipe and Sandpipers
Sc Common Snipe
Sc Spotted Sandpiper
Mp Solitary Sandpiper
Mp Long-billed Curlew
Scientific Name
Cathartidae
Cathartes aura
Accipitridae
Accipiter gentilis
Accipiter striatus
Accipiter cooperii
Buteo jamaicensis
Buteo
Buteo
swainsom
lagopus
Buteo regal is
Aqui1 a chrysaetos
Haliaeetus leucocephalus
Circus cyaneus
Pandionidae
Pandion
haliaetus
Falconidae
Falco rusticolus
Falco mexicanus
Falco peregrinus
Falco columbarius
Falco sparverius
Tetraonidae
Dendragapus obscurus
Meleagrididae
Meleagris gallopavo
Gruidae
Grus canadensis
Rallidae
Porzana Carolina
Fulica americana
Charadriidae
Charadruis vociferus
Scolopacidae
Capella gallinago
Actitis macularia^
Tringa solitaria
Numenius americanus
A-34
-------
APPENDIX F (continued)
Code* Common Name
Snipe and Sandpipers (Cont.)
Mp Lesser Yellowlegs
Avocets
Mp American Avocet
Phalaropes
SMc Wilson's Phalarope
Mp Northern Phalarope
Gulls and Terns
Su California Gull
Mu Ring-billed Gull
Mp Franklin's Gull
Sp Forster's Tern
Pigeons and Doves
SMc Band-tailed Pigeon
Yc Rock Dove
Sc Mourning Dove
Typical Owls
Yc Great Horned Owl
Yp Pygmy Owl
Sp Burrowing Owl
Uu Long-eared Owl
Uu Saw-whet Owl
Nighthawks
Sc Common Nighthawk
Swifts
Sp Black Swift
Sc White-throated Swift
Hummingbirds
Sc Black-chinned Hummingbird
Sc Broad-tailed Hummingbird
Me Rufous Hummingbird
Kingfishers
Yc Belted Kingfisher
Woodpeckers
Yc Common Flicker
Yp Red-headed Woodpecker
Scientific Name
Scolopacidae
Tringa flavipes
Recurvirostridae
Recurvirostra americana
Phalaropodidae
Steganopus tricolor
Lobipes lobatus
Laridae
Larus californicus
Larus delawarensis
Larus pipixcan
Sterna forsteri
Columbidae
Columba
fasciata
Columba 1i v i a
Zenaida macroura
Strigidae
Bubo virginianus
Glaucidium gnoma
Athene cunicularia
Asio otus
Aegolius acadicus
Caprimulgidae
Chordeiles minor
Apodidae
Cypseloides niger
Aeronautes saxatal is
Trochilidae
Archil ochus
alexandri
Selasphorus
Selasphorus
platycercus
rufus
Alcedinidae
Megaceryle alcyon
Picidae
Colaptes auratus
Melanerpes erythrocephalus
A-35
-------
APPENDIX F (continued)
Code'
Mu
Sc
Su
Yc
Yc
Yc
Sp
SMc
Sc
SMc
SMc
SMu
Sp
Sc
Sc
Yc
Sc
Sc
Sc
Sc
Sc
Mp
Yc
Yc
Yc
Yc
Yc
Yc
Yc
Yc
Yc
Yc
Yp
Common Name
Woodpeckers (Cont.)
Lewis' Woodpecker
Yellow-bellied Sapsucker
Williamson's Sapsucker
Hairy Woodpecker
Downy Woodpecker
Northern Three-toed Woodpecker
Scientific Name
Picidae
Asyndesmus lewis
Sphyrapicus varius
Sphyrapicus thyroideus
Picoides villosus
Picoides pubescens
Picoides trldactylus
Flycatchers
Eastern Kingbird
Western Kingbird
Say's Phoebe
Western Flycatcher
Hammond's Flycatcher
Dusky Flycatcher
Gray Flycatcher
Western Wood Pewee
Olive-sided Flycatcher
Larks
Horned Lark
Swallows
Violet-green Swallow
Tree Swallow
Rough-winged Swallow
Barn Swallow
Cliff Swallow
Jays and Crows
Blue Jay
Steller's Jay
Scrub Jay
Black-billed Magpie
Common Raven
Pinyon Jay
Clark's Nutcracker
Chickadees and Titmice
Black-capped Chickadee
Mountain Chickadee
Plain Titmouse
Nuthatches
White-breasted Nuthatch
Red-breasted Nuthatch
Tyrannidae
Tyrannus tyrannus
Tyrannus vertical is
Sayornis saya
Empidonax difficilis
Empidonax hammondii
Empidonax oberholseri
Empidonax wrightii
Contopus sordidulus
Nuttallornis boreal is
Alaudidae
Eremophila alpestris
Hirundinidae
Tachycineta thalassina
Iridoprocne bicolor
Stelgidopteryx ruficollis
Hirundo rustica
Petrochelidon pyrrhonota
Corvidae
Cyanocitta cristata
Cyanocitta stelleri
Aphelocoma coerulescens
Pica pica
Corvus corax
Gymnorhinus cyanocephalus
Nucifraqa columbiana
Paridae
Parus bicolor
Parus gambeli
Parus inornatus
Sittidae
Sitta carolinensis
Sitta canadensis
A-36
-------
APPENDIX F(continued)
Code* Common Name
Creepers
Yc Brown Creeper
Dippers
Yc Dipper
Wrens
Sp House Wren
Sc Canyon Wren
Sc Rock Wren
Mimics
Mp Mockingbird
SMp Catbird
Sc Sage Thrasher
Thrushes and Bluebirds
Yc Robin
Sc Hermit Thrush
Sc Swainson's Thrush
Sp Veery
Uc Western Bluebird
Sc Mountain Bluebird
Yc Townsend's Solitaire
Gnatcatchers and Kinglets
Mp Blue-gray Gnatcatcher
Sc Golden-crowned Kinglet
SMc Ruby-crowned Kinglet
Pipits
Sc Water Pipit
Waxwings
Mp Bohemian Waxwing
We Cedar Waxwing
Shrikes
We Northern Shrike
Yc Loggerhead Shrike
Starlings
Yc Starling
Vireos
Sc Gray Vireo
Sc Solitary Vireo
Sc Warbling Vireo
Scientific Name
Certhiidae
Certhia
familiaris
Cinclidae
Cinclus mexicanus
Troglodytidae
Troglodytes aedon
Salpinctes mexicanus
Salpinctes obsoletus
Mimidae
Mimus
polyglottos
Dumetella carolinensis
Oreoscoptes montanus
Turdidae
Turdus migratorius
Catharus guttata
Catharus ustulata
Catharus fuscescens
Sia1ia mexicana
Sia1ia currucoides
Myadestes townsendi
Sylviidae
Polioptila
caerulea
Regulus
Regulus
satrapa
calendula
Motacillidae
Anthus spinoletta
Bombycillidae
Bombycilia garrulus
Bombycilla cedrorum
Laniidae
Lanius excubitor
Lanius ludovicianus
Sturnidae
Sturnus vulgaris
Vireonidae
Vireo
vicimor
Vireo solitarius
Vireo gilvus
A-37
-------
APPENDIX F (continued)
Code* Common Name
Warblers
Sc Orange-crowned Warbler
Sp Nashville Warbler
Mp Virginia's Warbler
Sc Yellow Warbler
SMp Black-throated Blue Warbler
SMc Yellow-rumped Warbler
Mp Townsend's Warbler
Mp Chestnut-sided Warbler
Sp MacGillivray's Warbler
Mu Yellowthroat
SMc Wilson's Warbler
Weaver Finches
Yc House Sparrow
Meadowlarks, Blackbirds and
Orioles
Sp Bobolink
Sc Western Meadowlark
SMc Yellow-headed Blackbird
Yc Red-winged Blackbird
Sc Northern Oriole
We Rusty Blackbird
Yc Brewer's Blackbird
Yc Common Crackle
Yc Brown-headed Cowbird
Tanagers
SMc Western Tanager
Grosbeaks, Finches, Sparrows
and Buntings
SMp Rose-breasted Grosbeak
Sc Black-headed Grosbeak
SMp Lazuli Bunting
Yc Evening Grosbeak
WMp Purple Finch
Yc Cassin's Finch
Yc House Finch
Yc Pine Grosbeak
We Gray-crowned Rosy Finch
We Black Rosy Finch
Yc Brown-capped Rosy Finch
We Common Redpoll
Yc Pine Siskin
Scientific Name
Parulidae
Vermivora celata
Vermivora ruficapilla
Vermivora virgim'ae
Dendroica petechia
Dendroica caerulescens
Dendroica coronata
Dendroica townsendi
Dendroica pensylyanica
Oporornis tolmiei
Geothlypis trichas
Wilsonia pusilla
Ploceidae
Passer domesticus
Icteridae
Dolichonyx oryzivorus
Sturnella neglecta
Xanthocephalus xanthocephalus
Agelaius phoeniceus
Icterus galbula
Euphagus carolinus
Euphagus cyanocephalus
Quiscalus quiscula
Molothrus ater
Thraupidae
Piranga
ludoviciana
Fringillidae
Pheucticus ludovicianus
Pheucticus melanocephalus
Passerina amoena
Hesperiphona vespertina
Carpodacus purpureus
Carpodacus cassinii
Carpodacus mexicanus
Pinicola enucleator
Leucosticte tephrocotis
Leucosticte atrata
Leucosticte austral is
Carduelis flammea
Carduelis pinus
A- 38
-------
APPENDIX F(continued)
Code* Common Name
Grosbeaks, Finches, Sparrows
and Buntings
SMp American Goldfinch
SMc Lesser Goldfinch
Sc White-winged Crossbill
SMc Green-tailed Towhee
Sc Rufous-sided Towhee
Mp Lark Bunting
Sc Savannah Sparrow
Mp Vesper Sparrow
SMc Lark Sparrow
WMc Dark-eyed Junco
Yc Gray-headed Junco
We Tree Sparrow
Sc Chipping Sparrow
Mp Brewer's Sparrow
Wp Harris1 Sparrow
SMc White-crowned Sparrow
Yc Song Sparrow
Sc Lincoln's Sparrow
Mp Swamp Sparrow
Scientific Name
Fringillidae
Carduelia tristis
Carduelia psaltria
Loxia leucoptera
Pipilo chlorura
Pipilo erythrophthalmus
Calamospiza melanocorys
Passerculus sandwichensis
Pooecetes gramineus
Chondestes grammacus
Junco hyemalis
Junco caniceps
Spizella arborea
Spizella
Spizella
passerina
breweri
Zonotrichia querula
Zonotrichia leucophrys
Melospiza melodia
Melospiza 1incolnii
Melospiza georgiana
Y = Year-round resident
M = Migrant, only seen during migratory periods
S = Summer resident
W = Winter resident
U = Unknown
e = Endangered. A wildlife population is endangered when its prospects
for survival and reproduction within an area are in jeopardy or are
likely to become so within the foreseeable future. Any substantial
reduction or displacement of a wildlife population resulting from a
change in land use could cause an otherwise normal population to
become endangered in status.
t = Threatened. A wildlife population is rated threatened when the
individuals constituting the population exist in such small numbers
or are so restricted in their general distribution that they may
become endangered.
c = Common. A population is considered common when its level is com-
patible with the existing habitat and is currently secure because
its essential habitat is not threatened by environmental degradation.
p = Peripheral. A peripheral population is one which, because of being
on the perimeter of its normal geographical range, occurs in low
A- 39
-------
APPENDIX F (continued)
numbers. Although not endangered or threatened in its population
distribution as a whole, peripheral populations are subject to
becoming endangered by relatively minor changes in their habitats.
Such populations are seldom of substantial state interest unless
habitat enhancement measures will result in their status being
upgraded.
u = Undetermined or unknown.
Sources: American Ornithologist's Union (1957, 1973), Bailey and
Niedrach (1965), Colorado Division of Wildlife (1975), and
A- 40
-------
APPENDIX G
Macro-Invertebrate Abundance, Upper Eagle River Valley, Colorado.1
Station Number-River Mileage
57.7-0.5
57.7-10
50
49.9-0.1
49.5
49.3-1.0
48
47.5
46.5 If
46.5 rt
44.2
43.8-0.2
43.8-4.0
42.5
40.1
Station Description
Eastfork of Eagle River 0.5 Mile Up-
stream of Confluence
West Fork of Eagle River 1 Mile Upstream
from Confluence
Eagle River 0.5 Mile Upstream of
Redd iff, Colorado
Turkey Cr. One-tenth Mile Upstream of
Confluence with Eagle
Eagle River 0.2 Mile Upstream of the
Confluence with Homestake Cr.
Homestake Creek One Mile Upstream
from Confluence with Eagle River
Eagle River 0.5 Mile Upstream from
Belden
Eagle River at Gelman Upstream of
Tailings Piles
Eagle River (left bank) at Discharge of
Old New Jersey Tailings Ponds. Not
Influenced by Discharge.
Eagle River (right bank) at Discharge
of Old New Jersey Tailings Ponds. In-
fluenced by Discharge.
Eagle River Upstream from Spring Effluent
of New Jersey Zinc Tailings Ponds
Cross Creek 0.2 Mile Upstream from
Eagle River
Cross Creek 0.5 Mile Upstream from
New Jersey Zinc Tailings Ponds Effluents
Eagle River One Mile Upstream of
Minturn, Colorado
Eagle River 1.5 Mile Downstream of
Minturn, Colorado, One Mile Upstream of
Gore Creek Confluence
A- 41
-------
APPENDIX G (continued)
Station Number-River Mileage
39.9-4
39.9-1.0
13.1
11.9
6.8
0.2
46.5-0.1
44.1-0.2
43.8-3.0-0.1
Station Description
Gore Creek One Mile Upstream of Vail,
Colorado
Gore Creek One Mile Upstream of Con-
fluence with Eagle River
Eagle River 0.5 Mile Upstream of
Eagle, Colorado
Eagle River One Mile Downstream of
Eagle, Colorado
Eagle River 1.0 Mile Downstream of
Gypsum, Colorado
Eagle River 0.2 Mile Upstream from the
Confluence with the Colorado
Effluent from Old New Jersey Zinc
Ponds
Spring Drain from New New Jersey Zinc
Ponds
Effluent from New New Jersey Zinc Ponds
to Cross Creek
A- 42
-------
APPENDIX G (continued)
39^-4 39.9-1.0 13.1 11.9 6.8 0.2 46^.5-0.1 i4_._l-0_.2 43.8-3.0-0.1
Stonef1ies
Pteronarcys sp. -- -- -- -- 1
Pteronarcella sp. -- 9 7 96 2
Brachyptera sp. 4 5 3 -- 1 3
Isoperla sp. -- 7 -- 32
Mayflies
Heptagenia sp. 1 1 3 -- 4 6
Rhithrogena sp. 14 2 4 -- 1 G
Ephenerella sp. 26 25 -- 34
Baetis sp. 2 1
Pacudocloeon sp. -- -- -- -- -- 2
Caddis flies
Heliopsyche sp. -- -- 6 1
Glossosoma sp. -- 79 29 24 129
Brachycentrus sp. 20 185 141 256 243 26
Hydropayche sp. -- -- 13 128 31 170
Cheumatopsyche sp. -- -- -- -- 7 162
Arctopsyche sp. 4 37 3
Agraylea sp. -- -- -- -- -- 5
Psychomyia sp. -- 2
Beetles
Heterlimnium sp. -- 35 640 10
Optioservus sp. -- -- -- 560 9
Blackflies
Prosimulium sp. -- -- -- -- -- 1
Midges
I'icrotendipes sp.
Spaniotoma sp.
Cricotopus sp.
Tipulidae
Atherix sp.
Blepharoceridae
Sludgeworms
Ho. of Kinds
Number Per Sq. Ft.
4
8
75
10
3
11
4
2
17
385
1
2
3
12
214
80
1
2
11
1335
1
15
453
3
1
2
13
390
CHEMICAL DATA - mg/1
Total Iron
Chronii un
Manganese
Zinc
Copper
Molybdenum
Lead
<0.2
-0.02
•0.1
•0.02
<0.02
-0.5
0.01
0.2
• 0.02
<0. 1
0.02
•0.02
-------
G 'runt ,!„„.,|
1217.4-0.2
Stonef 1 ies
Brachvptera sp.
Isoperla sp.
Pteronarcel la sp.
Nemoura sp.
Mayflies
Ephemerel la sp.
Heptagenia sp.
Baetis sp.
Pseudocloeon sp.
Rhithrogena sp.
Paraleptophlebia sp.
Caddis flies
Psychomyia sp.
Arctopsyche sp.
Brachycentrus sp.
Polycentropus sp.
Glossosoma sp.
Hydropsy che sp.
Beetles
Heterlinnius sp.
Optioservus sp.
Cylloepus sp.
nidges
Spaniotoma sp.
Pseudochironorous sp.
Pentaneura sp.
Cricotopus sp.
Athenx sp.
Tipul idae
Biting Midges
Palpomyia sp.
Psychodidae
Enpididae
Planarians
Nenatodes
Sludgeworms
Number of Kinds
Number Per Sq. Ft.
CHEMICAL DATA - mg/1
Total Iron
Chromium
Manganese
Zinc
Copper
Itolybdenum
Lead
57.7-0.5 57.7-1.0 50
8 1 7
3
1
--
60 10 33
3 3 1
7 26
6
--
--
4 1
4 3 100
12 -- 21
4
10
--
12 18 26
5
--
4 6 2
4
6
--
..
.-
3
8 -- 1
1 1
..
2
2
11 14 14
132 66 241
0.2 0.6 0.2
0.02 -0.02 0.02
-0.1 0.1 0.1
-0.02 0.02 0.02
•0.02 0.02 0.02
'0.5 '0.5 0.5
0.02 o.oi o.ni
49.9-0.1 40 5
20
M 7
3
3 1
50 141
5
45 11
37 2
._
..
20
3 9
88 11
.-
72
--
3 19
4
--
19 56
..
5
--
..
8 17
--
1 1
2 2
1
1 1
--
16 19
323 307
0.2
0.02
0.1
0.02
0.02
0.5
0.01
"9. 1-1 .0
17
12
16
2
IN
2
__
--
--
.-
37
17
--
1
--
1
--
--
5
--
2
--
--
__
2
--
--
--
--
36
14
264
0.5
•0.02
0.1
0.02
0.02
0.5
0.01
4:1
2
1
._
--
22
2
2
..
--
1
15
4
--
--
--
1
--
--
80
--
--
28
--
5
--
--
--
5
4
30
15
202
0.5
0.02
0.1
0.13
0.02
0.5
0.01
47.5
11
15
--
11
__
--
..
--
--
3
3
--
--
--
--
--
--
30
--
--
--
1
1
--
--
--
_-
--
2
9
77
0.4
0.02
0.1
o.o:
o.o?
0.5
0.01
46.5
Ot
n
--
.-
2
„_
__
--
a
15
1.0
•0.02
4.3
1.7
0.02
0.5
0.02
4}. 3-4.0
4
2
.-
6
44
12
2
2
--
2
--
6
14
--
38
--
--
--
--
--
13
--
--
--
2
--
-.
--
_..
__
6
14
153
0.2
-0.02
0.1
0.02
0.02
• 0.5
0.01
.':.:
4
4
--
--
--
--
--
--
--
--
--
22
--
--
--
--
--
--
--
4
--
--
--
--
--
--
--
__
--
4
34
1.4
•0.02
2.0
0.58
0.02
0.5
0.01
^ " 1
7
-
11
--
6
--
1
--
--
--
--
12
1
--
\
--
c
--
2
* ~
--
.-
if
--
;
--
--
--
--
14
i;:
•- 3
•:.C2
~ .-~
-i -^
Q.i
O.?l
-------
APPENDIX H
AQUATIC ANIMAL SPECIES KNOWN TO OCCUR IN EAGLE COUNTY, COLORADO
Common Name
Fish
Kokanee Salmon
Mountain Whitefish
Cutthroat Trout
.Rainbow Trout
Brown Trout
Brook Trout
Lake Trout
Arctic Grayling
Goldfish
Bonytail
Roundtail Chub
Colorado Squawfish
Speckled Dace
Longnose Sucker
Crustaceans
Fairy Shrimp
Water Fleas
Fish Lice
Opossium Shrimp
Aquatic Sow Bugs
Scuds
Population
Status
c
P
c
c
c
c
c
P
u
e
c
e
c
c
u
c
c
u
c
c
1 Species listed are all year-round residents of Eagle County.
2 c = common; e = endangered; u = undetermined or unknown;
p = peripherial (occurrence within the county is on the peri-
meter of the animals normal geographical range — it therefore
occurs in low numbers).
3 Species which are found within the study area.
SOURCE: Based on the Colorado Division of Wildlife's Master
~, ,. r.:_74. nf Colorado Wildlife for Eagle County, 1975
A-45
-------
APPENDIX I
Explanation of Bedrock Geology Units
Qal
Alluvium
PHYSICAL DESCRIPTION: Alluvium of streams tributary to Eagle,
Colorado and Fryingpan Rivers. Composition depends on
source. Generally consists of fine-grained sandy silts
and silty clays with minor gravel. Generally less than
20 feet thick. May show bedding in part but changes
abruptly laterally. Deposit generally thick in the middle
and thin on the edges.
TOPOGRAPHIC EXPRESSION: Generally flat with a thin vegetative
cover. The area is subject to recurrent erosion and
deposition.
WEATHERING CHARACTERISTICS: Composed of transported colluvium
or material weathered from bedrock. Not appreciably
affected by additional weathering.
WORKABILITY: Excavation easy with backhoe or other power
equipment, may have locally high water table. Compaction
moderately easy, rollers and vibratory compactors
suggested. If organic material constitutes more than
10 percent by volume, the material should not be used
in compacted fill, as it may rebound when wet. Drilling
easy.
DRAINAGE AND ERODIBILITY: Infiltration rapid in sandy areas,
slow in clayey areas. Runoff rapid when water table is
at the surface. Moderately rapid during period of high
rainfall. Easily erodible by both gully wash and stream
scour.
GROUND WATER CHARACTERISTICS: Permeability moderate. Water
table at or near the surface. Well yield not developed,
normally high during water flow in stream but is tributary.
Quality generally highly mineralized, good for stock
use.
WASTE DISPOSAL: Very poor for septic systems and dump sites
due to ground water pollution hazard.
FOUNDATION STABILITY; Generally good but high ground water
table common.
SLOPE STABILITY: Generally stable, may have high ground water
table.
A-46
-------
RELATED GEOLOGIC HAZARDS: Within physiographic flood plain
may be susceptible to recurrent floodinq.
KNOWN AND POSSIBLE RESOURCES: Generally suitable for most
construction and non-construction purposes such as
layering in land fill, road fill, etc.
Qm
Glacial Moraine
PHYSICAL DESCRIPTION; Boulders, gravel, sand and silt deposited
by glaciers. Generally less than 100 feet in thickness,
but may reach 200-300 feet thickness. Consists primarily
of Precambrian granites and gneisses.
TOPOGRAPHIC EXPRESSION: Low hummocky topography, generally
vegetated with local high water table.
WEATHERING CHARACTERISTICS; Little soil, mainly forest mat
over the humirocky topography. Pocks in the noraine may
be decomposed.
WORKABILITY; Excavation difficult to easy, large boulders may
be encountered locally. Backhce can be used in some
areas. Compaction moderately easy, vibratory compactors
and smooth tired rollers commonly used, easy where large
boulders are absent or removed before emplacement.
Drilling easy to difficult, depending on numbers of
cobbles and boulders present.
DRAINAGE AND ERODIBILITY; Infiltration generally moderate to
rapid, may be local pending in clay enriched areas.
Runoff moderately slow on slopes. Erodibility slight
by sheet and gully wash, moderate to high by stream
scour.
GROUND WATER CHARACTERISTICS; Permeability high. Water table
at or near land surface. Well yield not developed, may
be good supply but is seasonal. Quality varies but is
generally good with domestic and stock use.
WASTE DISPOSAL; Septic Systems, satisfactory to unsatisfactory
depending on percolation rates and ground water levels.
Dump sites, poor because excavation may be difficult and
hazard of ground water pollution is high.
FOUNDATION STABILITY; Generally good below frost heave 2one.
A-47
-------
SLOPE STABILITY: Moderate, material is generally unconsoli-
dated and may slide if it becomes water saturated on
moderate to steep slopes. Vertical cuts may stand for
several months but will ravel and slump on wetting and
drying over several seasons. Angle of repose about 35°.
REALTED GEOLOGIC HAZARDS: May have potentially unstable slopes
in steeper areas and in water saturated areas.
KNOWN AND POSSIBLE RESOURCES; Possible local source of fair
quality aggregate. May locally be good for filter drain.
Ti
Tertiary Intrusives
PHYSICAL DESCRIPTION: Regionally the tertiary intrusives range
from porphiritic to basaltic dikes and sills. Many of
the sills are less than five feet thick. The only tertiary
intrusive within the study area is a latite porphyry
sill which follows the right bank of the Eagle River
at Red Cliff. The sill reaches a maximum thickness of
150 feet a mile southeast of Red Cliff, then thins to
the northwest and feathers out just south of Two Elk
Creek. This sill is the caprock for the zinc-bearing
Gilman ore body in the Leadville Limestone.
TOPOGRAPHIC EXPRESSION: Narrow Tertiary intrusive sills run
parallel to bedding planes in much of the stratigraphic
sequence. The sill near Red Cliff intrudes between the
Leadville Limestone of Mississippian age and the Penn-
sylvanian Maroon Formation.
WEATHERING CHARACTERISTICS: Generally resistant except for
narrow sills in sedimentary section. Intermittent streams
on flow surfaces may show some joint control. At edges
of volcanic flows coarse talus tends to accumulate.
Forms prominent ridge south of Red Cliff.
WORKABILITY: Excavation difficult to very difficult, with
degree of jointing the critical factor. Blasting would
probably be necessary over much of the area. Compaction
difficult and generally requires crushing and mixing
with binder material. Steel wheeled and rubber-tired
rollers suggested. Drilling moderate to difficult.
A-48
-------
DRAINAGE AND ERODIBILITY: Infiltration into rock negligible.
Moderate to slow through fractures. Runoff rapid to
moderate. Erodibility very resistant for igneous rocks
such as the porphyry near Red Cliff. Some ash flows
and tuffaceous Tertiary volcanics easily eroded.
GROUND WATER CHARACTERISTICS: Permeability generally poor,
with joint and fracture density the critical factor.
Water table unknown, may be essentially nonexistent due
to porosity and thickness of sills in most places. May
be present locally in open but discontinuous fractures
and in shallow depressions not buried by flows. Well
yield undeveloped, probably undependable. Yields water
in small amounts as generally temporary springs at base
of unit, notable after snow melt or heavy rain. Water
quality unknown, probably good with moderate mineralization
Has been developed and used as minor source for stock
use in some areas.
WASTE DISPOSAL: Septic systems unsatisfactory due chiefly to
lack of material for burial. Pollution of local ground
water by leakage through fracture systems is a possibility.
Dump sites unsuitable, chiefly because excavation of
sanitary cover is difficult. Great risk of ground water
pollution through fracture systems.
FOUNDATION STABILITY: Excellent. May be some danger of rockfall
and unstable slopes at margins of excavations. In other
areas of the county ash falls have poor stability for
foundations and are subject to swelling.
SLOPE STABILITY: Mostly excellent, but poor to fair within
twenty-five feet of margins due to rockfall. Very poor
in ash falls of other areas.
RELATED GEOLOGIC HAZARDS; Rockfall hazard should in general be
considered high near margins of the sills. Talus slopes
are developed along many of the margins overlying poten-
tially unstable materials. Large blocks along margins
may fall as an occasional occurence. Small landslides
common on ash flows and tuffaceous sedimentary rocks in
other regions of Eagle County.
KNOWN AND POSSIBLE RESOURCES; Possible source of riprap, crushed
aggregate and road aggregate.
A-49
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JPPm
Maroon Formation
PHYSICAL DESCRIPTION: Approximately 1,000 to 4,000 feet of red
mudstones, shale, siltstone and fine-grained sandstone.
Unit is designed as all rocks above the Jacque Mountain
Limestone and below the Weber Sandstone or the Chinle,
whichever is present. The following sample date were
taken from deep drill holes and can be considered average
data for unweathered bedrock: moisture content, 1.05-5.05%;
density, 141-164 pcf; shear strengths, 231-6254 psi;
modulus of elasticity, 6.3-102 x 104 psi.
TOPOGRAPHIC EXPRESSION: South facing scarp slopes generally
grassy or shrub covered. North facing scarp slopes
generally wooded. Scarp slopes gentle to greater than
40°. Bedding is generally seen as light and dark colored
bands on grassy slopes.
WEATHERING CHARACTERISTICS; Weathers to fine red silty clay-
WORKABILITY: Excavation easy to moderate in weathered zone,
becoming more difficult with depth. Tractor drawn
scrapers and rippers suggested. Compaction generally
good, but sandstones may have to be combined with binder
before compaction with smooth tired rollers. Drilling
moderate to difficult.
DRAINAGE AND ERODIBILITY; Infiltration generally negligible in
shales, negligible to low in siltstones and sandstones,
moderate along fractures and joints. Runoff, moderate.
Fairly resistant to stream scour and moderately resistant
to gully and slope wash.
GROUND WATER CHARACTERISTICS; Permeability generally negligible
to low, low in weathered zone. Water table unknown, pro-
bably varies greatly. Well yield not developed, probably
poor to fair depending upon location, with siltstones and
sandstones giving best yield. Quality probably highly
mineralized with possible stock use.
A-50
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V7ASTE DISPOSAL: Septic systems generally unsatisfactory, shales
too impermeable with possibility of ground water pollution
in siltstones. Dump sites qenerally fair to poor, diffi-
cult to excavate in many areas with associated hazard of
ground water pollution.
FOUNDATION STABILITY; Good. Blocks may slide on bedding planes
into excavations. Shales may be expansive in part.
SLOPE STABILITY: Dipslopes on shale may tend to slide. Bedding
that dips into cuts may slide on the dipalopes. Steep
slopes initiated by construction may alter drainage and
initiate slides in the weathered zone.
RELATED GEOLOGIC HAZARDS: Potentially unstable slopes and snow
avalanche hazard at higher elevations and in steep valleys
are primary hazards. Dipslope sliding of weathered
bedrock is alsc possible.
KNOWN AND POSSIBLE RESOURCES; Generally suitable for most con-
struction and non-construction purposes, road fill,
layering in land fills, etc.
TPe
Eagle Valley Formation
ffeg
Bedded Evaporites
PHYSICAL DESCRIPTION; Evaporite interval consists of lense shaped
deposit about 3,000 feet thick with deepest portion near
the center of the county- Interfingers with the I"inturn
Formation on the east and Morgan Formation on the west.
At type locality is mainly light colored gypsiferous mud-
stone and siltstone containing seme bedded gypsum, a few
cherty dark gray limestone beds about one foot thick, a
few beds of reddish shale and siltstone. In some areas
the gypsum is massively bedded, displays chaotic internal
structure in bluffs. Halite locally common.
TOPOGRAPHIC EXPRESSION: Irregular topography with bluffs and
sinkholes.Landslide topography in areas of steep slopes.
WEATHERING CHARACTERISTICS; Weathers very rapidly and is water
soluble. Forms large solution cavities in some areas.
Slopes generally unstable in bedded deposits.
WORKABILITY; Excavation very easy. Compaction generally easy-
Poorly consolidated, not recommended! for road beds or
foundations.
A-51
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DRAINAGE AND ERODIBILITY: High infiltration in many areas,
moderate in gypsiferous mudstones and shales. P.unoff
moderate. Easily erodiblc by stream, oully and slope
wash. Poorly cemented by water soluble materials.
GROUND WATER CHARACTERISTICS: Permeability generally high,
moderate in impure rock materials such as gypsiferous
mudstones. Water table unknown. Well yield unknown,
probably unreliable. Quality highly mineralized, highly
corrosive, potassium salts identified in some drill holes,
no known use.
WASTE DISPOSAL; Septic systems unsatisfactory because of high
permeability and ground water pollution hazard. Dump
sites very poor because of high permeability and hazard
of ground water pollution.
FOUNDATION STABILITY; Fair, control of surface and sub-surface
drainage is critical.
SLOPE STABILITY: Subsidence of the surface due to solution.
Landslides and general instability of the slopes are the
major geological hazards.
RELATED GEOLOGIC HAZARDS; Relatively unstable slopes, numerous
landslides because of infiltration and solubility of
bedrock. Sink holes and solution caverns.
KNOWN AND POSSIBLE RESOURCES; Gypsum and other evaporites may
be economically feasible under part of the Eagle River
Valley in the future. Various agricultural purposes.
IPm
Minturn Formation
PHYSICAL DESCRIPTION; About 6,000 feet of interbeddec" medium
to very coarse grained gray to reddish-brown sandstone,
conglomeratic sandstone, thin beds of reddish-brown silt-
stone and sandy to silty shale with distinctive interbedded
pink to gray limestones and dolomites. Overlies the
Belden or on Precambrian rocks and is below the Maroon.
Interfingers with the Eagle Valley Formation west of Dowds
Junction. Testing of unweathered sandstones and concilo-
merates within the Minutrn yield: moisture content, 6.1-
10.9%; unit weight, 130.9 pcf-166.5 pcf; modulus of
elasticity, 1.0-12 x 10^ psi. Shales may be expected to
have different values.
TOPOGRAPHIC EXPRESSION: Generally forms steep slopes with lime-
stones making prominent steps on the slopes. Fomc both
grassy and tree covered slopes.
A-52
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WEATHERING CHARACTERISTICS; Weathers to a rec? silty clay staining
the gray limestone steps a pinkish color.
WORKABILITY; Excavation easy to moderate in weathered zone,
becoming more difficult with depth. Blasting may be
required for deep excavations. Compaction generally
good, but coarser sandstones and limestones must be
mixed with binder before compaction. Drilling moderate
to difficult.
DRAINAGE AND ERODIBILITY; Infiltration generally negligible in
shales and negligible to low in siltstones, sandstones,
limestones, conglomerates. Moderate along fractures and
joints. Runoff moderate to high. Erodibility, fair
resistance to stream scour and moderate resistance to
gully and slope wash.
GROUND VJATER CHARACTERISTICS; Permeability generally negligible
to low,low in weathered zone, moderate in fractured areas.
Water table unknown, probably varies. Well yield un-
developed, probably poor in shales to fair in siltstones,
sandstones, conglomerates and limestones. Water pro-
bably mineralized, probably used for stock and some
domestic.
WASTE DISPOSAL: Poor for septic systems, hazard of ground water
pollution in sandstones and siltstones may be moderate.
Dump sites, generally unsatisfactory, excavation difficult
and hazard to ground water source.
FOUNDATION STABILITY: Generally good.
SLOPE STABILITY; Dipslopes on shale may tend to slide. Bedding
that dips into cuts may slide on bedding planes. In
many areas as steep slopes are developed, construction
nay alter drainage in the weathered zone and may initiate
slides.
RELATED GEOLOGIC HAZARDS; Potentially unstable slopes and
snow avalanches at higher elevations in the steep valleys
are primary hazards involved. Some landsliding in wea-
thered zone and on bedding surfaces may occur.
KNOWN AND POSSIBLE RESOURCES; Generally suitable for construction
and non-construction purposes. Limestones may provide
local source of aggregate. Has been prospected for
uranium in the Vail area.
A-53
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IPb
Belden Formation
PHYSICAL DESCRIPTION: Alternating beds of dark gray or black
fine grained fossiliferous limestones and gray to black
fissile shale. Two massive, arkosic conglomeratic sand-
stone units occur near the middle of the formation and
a few beds of micaceous siltstone occur near the top
of the unit. Thickness ranges from 700 to 125 feet,
with generally two-thirds of the formation comprised
of shale. Beds are discontinuous and lie on a karst
surface at the top of the Leadville Limestone. The
cave fillings and red regolith on top of the Leadville
is termed the Molas Formation and is included with the
Belden Formation for simplicity. Sandstone porosity
is 10 to 15%. Shales are expansive in part.
TOPOGRAPHIC EXPRESSION: Generally occurs in valleys and is
poorly exposed. Limestones and sandstones form resistant
ridges on the slopes.
WEATHERING CHARACTERISTICS; Weathers to a gray to buff silt
with small pieces of limestone, sandstone and shale.
WORKABILITY; Excavation easy to difficult with most power
equipment. Thin limestones and shales are ripable.
Thicker sandstones and limestones may require blasting.
Compaction easy in shales, limestones and sandstones
should be removed, crushed and mixed with binder before
emplacement. Sheepsfoot and smooth tired rollers
suggested. Drilling moderate to difficult.
DRAINAGE AND ERODIBILITY: Infiltration negligible in shales,
moderately high in sandstones and less so in limestones.
Fractures and solution channels along fractures allow
infiltration in local areas. Runoff moderate to high
on shales, less so on sandstones and limestones. Erod-
ibility moderate in shales by gully wash and stream
scour, slight by sheet wash.
GROUND WATER CHARACTERISTICS; Permeability generally poor,
may be fair at base of weathered zone, moderate through
sandstones and in areas of solution channels. Water
table unknown, probably varies. Water quality probably
mineralized.
WASTE DISPOSAL; Septic systems generally fair to poor, per-
colation rates too slow. Risk of polluting ground water
source in sandstone and limestone. Dump sites fair to
good. Good in thick shale units. Fair to poor in
sandstone and limestones where there is ground water
pollution hazard.
A-54
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FOUNDATION STABILITY: Fair. Shales may be expansive in part.
SLOPE STABILITY: Expansive, in part, susceptible to low angle
slumping and slope failures. Beds dipping into cuts
may fail.
RELATED GEOLOGIC HAZARDS: Formation is susceptible to slope
failures and may contain expansive clays in part.
KNOWN AND POSSIBLE RESOURCES: Suitable for most construction
and non-construction purposes such as sanitary land fill
layering, some road fill, etc.
Ml
Leadville Limestone
PHYSICAL DESCRIPTION: Consists of two members in Eagle
County. The lower sandstone unit, called the Oilman
Sandstone member, ranges from 10 to 50 feet in thick-
ness and is discontinuous in some areas. It is composed
of thin and uneven beds of grayish-brown medium-grained
calcareous sandstone. The lower few feet consist of a
light-gray, sandy, dolomite breccia that fills depressions
in the underlying Dyer Dolomite. Above the Oilman member
is about 75 feet of dense, hard, locally silicified
dark-gray lithographic limestone. It is generally
evenly massive bedded except the lower units that are
thin and contain limestone pebbles. The thickness may
range between wide limits in some areas because of post
Leadville erosion. Beds are continuous.
TOPOGRAPHIC EXPRESSION: Forms prominent ridges and cliffs.
WEATHERING CHARACTERISTICS: Oilman sandstone weathers to a
yellowish-brown sand. The main dolomitic limestone
unit has a characteristic bluish-gray color with even
smooth surfaces. In some of the nearby mining districts
it is hydrothermally altered.
WORKABILITY: Excavation difficult, blasting required.
Compaction difficult, must be crushed and thoroughly
mixed with binder before emplacement. Drilling
difficult.
DRAINAGE AND ERODIBILITY: Infiltration slow except through
fractured and jointed areas and solution cavities.
May be moderate in altered Oilman sandstone member.
Erodibility negligible by sheet wash, gully wash, slight
by stream scour. Some solution. Runoff high.
A-55
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GROUND WATER CHARACTERISTICS: Permeability negligible except
through fractures and solution cavities. May be fair
in altered sandstone. Water table varies greatly from
place to place and only occurs in fractured zones. Well
yield not developed because of solution cavities and
karst upper surface. Is a good aquifer in other areas
of the state. Quality of water mineralized and hard,
with domestic, stock and industrial use.
WASTE DISPOSAL: Septic systems poor, great hazard of polluting
widespread ground water supply. Dump sites poor,
difficult to excavate.
FOUNDATION STABILITY: Excellent.
SLOPE STABILITY; Excellent.
RELATED GEOLOGIC HAZARDS; Rockfall hazard near cliffs,
subsidence in some areas where solution cavities are
developed. Block slides may occur along bedding planes
on steep dip slopes.
KNOWN AND POSSIBLE RESOURCES: Limestone could be a source of
good quality aggregate and agricultural lime. Large
deposits of lead and zinc with associated gold, silver
and copper have been mined in nearby areas. These
deposits were found in hydrothermally altered areas.
DC
Chaffee Formation
PHYSICAL DESCRIPTION; Consists of two members; the Dyer
Dolomite and the Parting Quartzite. The Dyer member is
uniformly thin bedded, very finely crystalline, dense,
hard, gray dolomite. Unit thickness varies locally
from 75 to 150 feet. The upper portion of the Parting Member
is a white medium to coarse grained quartzitic sandstone.
It is usually massive and crossbedded with conglomeratic
lenses. Bedding is massive and uneven, the lower 5
to 10 feet consists of a gray shale. The Parting Member
thins towards the Gore Range and thickens southwestward to
about 100 feet in thickness.
TOPOGRAPHIC EXPRESSION; Forms prominent ridges and outcrops.
WEATHERING CHARACTERISTICS; Weathered surfaces of the Dyer are
light brown to light gray.
WORKABILITY; Excavation difficult, blasting may be required.
Compaction, should be crushed and mixed with binder
Drilling difficult.
A-56
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DRAINAGE AND ERODiBILITY: Infiltration negligible to slow, slow
through fractured and jointed zones. Runoff moderate
to high, depending on slopes. Streams may be joint
controlled. Erodibility low by sheet and gully wash
and stream scour.
GROUND WATER CHARACTERISTICS: Permeability generally low except
along joints and in fractures zones where it may be
moderate. Water table not known. Well yield undeveloped.
Water quality unknown.
WASTE DISPOSAL: Septic systems poor, percolation rates too
low. Dump sites poor, excavation difficult.
FOUNDATION STABILITY: Excellent.
SLOPE STABILITY: Good. Hazard of rockfall if bedding planes
dip into steep cuts and jointing is prominent.
RELATED GEOLOGIC HAZARDS: Rockfalls are hazard near cliffs.
KNOWN AND POSSIBLE RESOURCES: Parting quartzite member could
be useful as crushed aggregate. Suitable for most
construction and non-construction purposes.
Oh
Harding Quartzite
PHYSICAL DESCRIPTION: C6nsists of an upper unit of primarily
white,medium-grained vitreous orthoquartzites. The
lower few feet consist of irregular brown, dolomitic
and calcitic cemented sandstone beds with conglomeratic
lenses. The beds in the upper unit are massive and
occasionally cross-bedded. The beds in the lower unit
are lenticular and cross-bedded. Yellowish gray-green
sandstone is locally interbedded with the quartzite.
The formation is about 50 feet thick but thins abruptly
to the west and southeast.
TOPOGRAPHIC EXPRESSION: Resistant unit that forms ridges.
WEATHERING CHARACTERISTICS: Weathers to a gray sandstone.
Angular blocks at base of cliff.
WORKABILITY: Excavation difficult, blasting may be required.
Compaction, material will have to be crushed and mixed
with binder before emplacement. Vibratory compactors
suggested. Drilling difficult.
A-57
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DRAINAGE AND ERODlBILITY; Infiltration negligible in upper
quartzite,slight in underlying sandstone. Probably
best in fractured and jointed material. Runoff moderate
to high. Erodibility slight by sheet and gully wash,
moderate by stream scour.
GROUND WATER CHARACTERISTICS; Permeability poor, may be fair
in fractured zones and poorly cemented sandstones.
Water table unknown, probably varies. Well yield un-
developed. Water quality not known.
WASTE DISPOSAL; Septic systems poor, difficult to excavate,
percolation too slow. Dump sites poor, excavation
difficult.
FOUNDATION STABILITY: Excellent. Blocks may fall into
excavations.
SLOPE STABILITY; Rocks dipping into steep cuts may fall along
bedding or jointing.
RELATED GEOLOGIC HAZARDS: Rockfall hazard near base of cliffs.
KNOWN AND POSSIBLE RESOURCES: Upper unit may be good riprap
material and building stone.
Peerless Formation
PHYSICAL DESCRIPTION: The composition is highly varied but,
in general, is a brown, sandy dolomite, with streaks
and laminae of greenish-gray or dark red dolomite. The
dolomite grades laterally and vertically into dolomitic
sandstone. Brown or gray shale is interbedded with
the dolomite in the middle parts of the formation and
becomes predominant at the top. The dolomite beds are
thin and lenticular. The sandstone beds are usually
more massive, and show some crossbedding. The thickness
ranges from 35 to 112 feet.
TOPOGRAPHIC EXPRESSION; Moderately resistant unit forming low
rounded ridges.
WEATHERING CHARACTERISTICS: Weathers to dark-to-light reddish-
brown .
WORKABILITY: Excavation very difficult. Drilling and blasting
required.
A-58
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DRAINAGE AND ERODIBILITY: Infiltration slight, may be moderate
in fractured and jointed zones. Runoff moderate to
high. Erodibility slight by sheet and gully wash,
moderate by stream scour.
GROUND WATER CHARACTERISTICS; Permeability poor, may be fair
in fractured zones and poorly cemented sandstone. Water
table unknown, probably varies. Well yield undeveloped.
Water quality unknown.
WASTE DISPOSAL: Septic systems poor, excavation difficult,
percolation slow. Dump sites poor, excavation difficult,
FOUNDATION STABILITY: Excellent. Blocks may fall into
excavations.
SLOPE STABILITY; Bedding dipping into cuts may cause failures
of jointed bedrock.
RELATED GEOLOGIC HAZARDS: Rockfall hazard near base of steep
slopes. Bedrock may fail where bedding and joints dip
into cuts.
KNOWN AND POSSIBLE RESOURCES: Suitable for most construction
and non-construction purposes.
-Gs
Sawatch Quartzite
PHYSICAL DESCRIPTION; The Sawatch quartzite consists of three
lithological units. The lower unit is a medium-grained,
vitreous, white, orthoquartzite; the middle unit is
alternating beds of medium-grained, dolomitic, brown
sandstone and white orthoquartzite; and the upper unit
is fine-grained, vitreous, white orthoquartzite. The
quartzites are medium-bedded to massive, and show some
cross-bedding. The middle zone is thin bedded; and the
individual dolomitic beds are lenticular, grading into
quartzite laterally. The thickness of the formation
ranges from 190 to 216 feet, but on the average is about
200 feet thick.
TOPOGRAPHIC EXPRESSION; The upper and lower zones are highly
resistant and form prominent ridges across divide araas
and cliffs where the beds are more gently dipping. The
middle zone forms a steep slope between cliffs.
A-59
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WEATHERING CHARACTERISTICS: The upper and lower zones weather
to angular light brown or gray cliffs or large blocks.
The middle zone weathers to a dark brown steep slope.
WORKABILITY: Excavation very difficult, drilling and blasting
required. Compaction, rock would have to be crushed
and mixed with binder. Drilling difficult.
DRAINAGE AND ERODIBILITY; Infiltration negligible through rock,
slow to moderate through fractures. Runoff rapid to
moderate. Erodibility very resistant.
GROUND WATER CHARACTERISTICS; Permeability slight to low, low
~ in fractured and jointed areas. Water table unknown,
may be present in fractured areas. Well yield undeveloped,
probably unreliable.
WASTE DISPOSAL: Septic systems unsatisfactory, excavation and
burial difficult, no infiltration. Dump sites unsuitable
chiefly because excavation for sanitary layering difficult.
FOUNDATION STABILITY: Excellent.
SLOPE STABILITY: Rockfall hazard. Blocks may fall into cuts
if bedding and jointing dip into cuts.
RELATED GEOLOGIC HAZARDS; Rockfall hazard near edge and base
of cliffs.
KNOWN AND POSSIBLE RESOURCES: May be good riprap, crushed
aggregate and road aggregate. Suitable for construction
and non-construction purposes.
Igneous and Metamorphic Rocks
PHYSICAL DESCRIPTION: The Precambrian rocks include granites,
schists, gneisses and lamprophyres of the Sawatch and
Gore Ranges. The rocks are fine-to-coarse-grained, with
interlocking granular borders. Most have a pronounced
layering or foliation, are dense, hard, well jointed and
locally sheared. Grain-sizes range from 1 mm to 5 mm,
with coarse grains to 10 mm locally. The different
mineralogic units generally cover large areas but individual
rock types may be discontinuous over short distances.
TOPOGRAPHIC EXPRESSION: Rugged, rolling hills and mountains,
with numerous low rounded exposures. Forms the cores
of the Gore and Sawatch Ranges.
A-60
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WEATHERING CHARACTERISTICS: Extremely resistant and is generally
lichen covered; soils when present are very clayey sand,
indicating decomposition of the feldspars. May develop
good weathered horizon in sheared zones.
WORKABILITY; Excavation very difficult in unweathered rock,
generally requires blasting. Moderately easy to moderately
difficult in weathered rock. Commonly can be excavated
with rippers and scrapers, locally with front end loaders.
Compaction very difficult. Material would have to be
crushed and mixed with binder before emplacement. Drilling
very difficult.
DRAINAGE AND ERODIBILITY: Infiltration negligible into rock,
moderate to slow through widely spaced fracture systems,
moderate into fracture zones of faults. Runoff rapid
to moderate. Erodibility generally moderately resistani,
moderately erodable where weathered.
GROUND WATER CHARACTERISTICS: Permeability moderate to high
near surface through fractures and weathered rock,
decreases to negligible at 200 to 400 feet depth. Water
table may be present locally, mainly in fractures and
weathered rock, depth varies, depends on extent of
weathering and openness and continuity of fractures.
Well yield generally small to very small, 0-3 gpm, may
be much greater in fracture zones and shear zones. Depends
on openness and continuity of fractures. Quality of
water fair to good, locally moderately hard. Poor to
fair source for domestic and stock wells.
WASTE DISPOSAL: Septic systems locally unsatisfactory, per-
eolation too slow and material for burial lacking except
where well weathered and decomposed. Risk moderate to
high for pollution of nearby water supplies through
fractures. Dump sites, unsuitable chiefly because ex-
cavation for sanitary layering difficult, and material
too permeable. Access locally difficult with slight to
moderate risk of polluting nearby water supplies.
Sealing of fractures before use adviseable.
FOUNDATION STABILITY: Excellent. Caution advised within 25
feet of margin of excavation because of slope instability
and rockfalls.
SLOPE STABILITY: Mostly good, risk moderate of rockfalls and
small rock slides along steep slopes. Cuts locally
controlled by altitude of foliation, compositional layering
and fractures. Hazardous where these are undercut.
Stable highway backslopes cut nearly vertical are common.
RELATED GEOLOGIC HAZARDS: Rockfall or rockslide hazard, avalanch ?
hazard high above timberline.
A-61
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KNOWN AND POSSIBLE RESOURCES; Possible source of aggregate
and riprap.Generally satisfactory for most construction
and non-construction purposes. Gold and silver deposits
in quartz viens have been worked intermittently over
parts of the region.
SOURCE: Appendix I and Figure 8 , Map of Bedrock Geology
and Known or Potential Mineral Resources, were compiled
by William A. Gallant and Judi C. Culver of Charles
S. Robinson & Associates, Inc., at the request of Camp
Dresser & McKee. The information was compiled from
existing literature, aerial photography and from field
investigations made during the summer of 1975. All
information was edited and revised for this project
during February, 1976.
A-62
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APPENDIX J
Explanation of Geologic Hazard and
Engineering Geology Map
Geologic Hazard. Geologic hazard areas include
slope failure conditions where landslides or
rockfalls are a problem, floodplains, swamps and
debris fans where frequent flooding or hydrocom-
paction may be a problem. Specific explanations
of each hazard are included below:
Landslides. Mass movements where there is a
distinct surface of rupture or zone of weakness.
Subtypes indentified and described below.
Slope failure complex. Large areas of failure of
surficial and bedrock units. May consist of a
combination of slope failure types.
Debris slides. Landslide type consisting primarily
of surficial material.
Accelerated soil creep. Areas of colluvial slope
that is moving downslope at a relatively rapid
rate.
Rockfall hazard. .Areas of either active or potential
falling, rolling or sliding of large bedrock blocks.
Physiographic floodplain. The portion of a major
stream valley where erosion and deposition presently
occurs and is generally subject to flooding on an
approximate 25-year cycle.
Swamps. Areas where poor drainage or high ground
water cause permanent or seasonal saturation. Soils
may be compressable because of high organic content.
A-63
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Debris fan. Areas of possible recurrent flooding,
debris flows and hydrocompaction.
Subsidence. Areas that may be susceptible to
subsidence due to hydrocompaction in low density
soils.
Denotes the Eagle Valley Evaporite Sequence. This
sequence is included as a geologic hazard because
the gypsum beds within these rocks are highly
susceptible to solution, with resulting subsidence
of the topography. Other rock and soil units in
this area exhibit low strength and are prone to
landslides after subsidence has occured. The soils
also tend to be highly corrosive to steel and
moderately corrosive to concrete. Corrosivity
problems in this area are more significant than in
other areas of the District.
A-64
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SUGGESTED ENGINEERING GEOLOGY CATEGORIES
Basic geologic and engineering investigations of area
as required by Senate Bill 35, adequate for development
planning and generally for construction site selection.
A. High stable gravel covered terraces above the
physiographic floodplain. Emphasis on, but
not limited to, groundwater, surface and sub-
surface drainage, composition and characteristics
of underlying bedrock that may be penetrated and
possible resource evaluation.
B. Stable colluvium or bedrock on flat to gentle slopes,
Emphasis on, but not limited to, surface and sub-
surface drainage and slope stability.
C. Stable glacial material on flat to gentle slopes.
Emphasis on, but not limited to, surface and sub-
surface drainage, slope stability and possible
resource evaluation.
A-65
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General geologic and engineering investigations of area
required for development planning for each construction site.
A. Stable colluvium or bedrock on gentle slopes that
may have a thin gravel cap. Emphasis on, but not
limited to, surface and subsurface drainage, com-
position and characteristics of near surface bedrock
and slope stability.
B. Stable glacial deposits on gentle to moderate slopes.
Emphasis on, but not limited to, surface and sub-
surface drainage, slope stability and possible resource
evaluation.
Detailed geologic and engineering investigations of
entire area is required for development planning and for
selection of construction sites.
A. Stable colluvium and bedrock on gentle to moderate
slopes. Emphasis on, but not limited to, surface
and subsurface drainage, slope stability and possible
resource evaluation.
B. Thick colluvium on gentle to moderate slopes.
Emphasis on, but not limited to, expansive and
A-66
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corrosive soils, surface and subsurface drainage
and hydrocompaction.
C. Fine grained tailings deposit on flat to moderate
slopes. Emphasis on, but not limited to, slope
stability, corrosive material, surface and subsurface
drainage.
D. Debris fans. Gentle thick collovial slopes con-
sisting of fine to coarse rounded material. Emphasis
on, but not limited to, surface and subsurface
drainage, frequency and control of mudflows and debris
flows, hydrocompaction and possible resource evaluation,
Detailed geologic and engineering investigations required
for entire area for development planning and some construction
sites may require specialized geologic and engineering investi-
gations for design purposes.
A. Thin glacial deposits overlying potentially unstable
moderate to steep colluvial and bedrock slopes.
Emphasis on, but not limited to, slope stability,
surface and subsurface drainage.
B. Stable colluvium and bedrock on moderate to steep
slopes. Emphasis on, but not limited to, slope
A-67
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stability.- rockfall hazard, expansive and corrosive
soils and surface and subsurface drainage.
C. Potential rockfall areas associated with talus slopes
Medium to coarse blockly material deposited by rock-
fall at the base of cliffs. Emphasis on, but not
limited to, rockfall hazard, slope stability, surface
and subsurface drainage.
Detailed geologic and engineering investigations of entire
area required for development planning and specialized investi-
gations required for specific construction sites.
A. Rockfall hazard areas and talus on moderate to steep
bedrock and colluvial slopes. Emphasis on, but not
limited to, slope stability, surface and subsurface
drainage and expansive and corrosive soils.
B. Debris slides, bedrock slides and slope failure
complexes composed of poorly sorted thin to thick,
fine to coarse colluvial and bedrock on gentle to
steep slopes. Emphasis on, but not limited to, slope
stability, surface and subsurface drainage, corrosive
and expansive soils.
C. Stable or potentially unstable colluvium or bedrock
on moderate to steep slopes. Emphasis on, but not
limited to, slope stability, surface and subsurface
A-68
-------
drainage, debris flows in higher mountain areas.
D. Potentially unstable colluvium or gypsiferous bedrock
on gentle to steep slopes. Emphasis on, but not
limited to, hydrocompaction, subsidence due to solution,
surface and subsurface drainage, corrosive and ex-
pansive soils, and slope stability.
Extensive detailed geologic and engineering investigations
necessary for development planning. Most of the area within
this classification may not be suitable for permanent structures
A. Debris slides and slope failure complexes made up of
unsorted thick colluvial material on moderate to
steep unstable or metastable slopes. Emphasis on,
but not limited to, slope stability, surface and sub-
surface drainage, corrosive and expansive soils.
B. Areas of accelerated creep composed of colluvium or
bedrock on steep unstable or metastable slopes.
Emphasis on, but not limited to, slope stability,
surface and subsurface drainage, corrosive and ex-
pansive soils.
A-69
-------
Extensive detailed geologic and engineering field in-
vestigations required for development planning. Utility
corridors, temporary structures and some permanent structures
may utilize parts of these areas after extensive investigations
and design for the specialized problems involved.
A. Physiographic floodplain where erosion and deposition
is presently active and is generally subject to
recurrent flooding on an approximate 25-year cycle.
Emphasis on, but not limited to, frequency, depth
and control of water and water entrained debris.
SOURCE: Appendix J and Figure 1, Geologic Hazards and
Engineering Geology Map, were compiled by William
A. Gallant and Judi C. Culver of Charles S.
Robinson & Associates, Inc., at the request of
Camp Dresser & McKee. The information was compiled
from existing literature, aerial photography and
from field investigations made during the summer
of 1975. All information was edited and revised for
this project during February, 1976.
A-70
-------
APPENDIX K
Explanation of Soil Classifications
GEOMORPHIC STRUCTURE
The letters which appear beside the soils classifications
denote the geologic origin of the landform on which that
soil has formed. An explanations of these geomorphic deno-
tations appears below:
Denotes soils which have formed on the surface of
alluvial fans, and/or slope wash. The topographic
features are formed from sediments dropped by stream::,
or sheet erosion waters as their gradiant decreases
near valley bottoms until they cannot maintain
enough current speed to carry their full sediment
load. Part of the sediments are then deposited as
alluvial fans in stream beds or as slope wash at
the bottom of steep slopes where sheet erosion occurs.
The coarse portion of soils derived atop slope wash
deposits can be expected to be angular to sub-angular
because of their short transportation distance. The
coarse portion of soils derived from alluvial fan
surfaces can be expected to be sub-angular to sub-
rounded because of their longer transportation
distance and because of the smoothing action of
water. The pH of these soils should be near neutral,
with widely varied mineral content due to the divergent
source materials within stream transported materials.
Refers to soils formed on the surface of old stream
terraces. These stream terraces were the floodplains
fl-71
-------
of ancestral Eagle River and Gore Creek, before they
eroded their valleys down to their present elevations.
The coarse portion of soils formed on old stream
terraces can be expected to be sub-rounded, rounded
and well-rounded due to considerable tumbling and
smoothing which they received before deposition on
the floodplain of a major ancient stream. The pH
of these soils should be near neutral, with widely
varied mineral content due to the divergent source
materials within stream transported materials.
Denotes soils which have formed on the surface of
the modern floodplain of the Eagle River and Gore
Creek. The coarse portion of these soils may be
expected to be sub-rounded, rounded and well-rounded
due to considerable smoothing action of water before
deposition on the floodplain of a major stream.
The pH of these soils should be near neutral, with
widely varied mineral content due to the divergent
source materials within stream transported materials.
Water table in these soils can be expected to be
high, but varies with season and stream level.
Soils in these areas have formed in swamps, where
the water table intersects the land surface. Soils
formed in this environment can be expected to be
damp and poorly-drained with a high to moderate
organic content and few coarse components. The pH
of these soils can be expected to be less than 7
due to formation of organic acids from decaying
plant material.
Refers to soils formed in unstable colluvium on the
surface of landslide complexes such as bedrock slides,
surficial slides and talus slopes. The coarse portion
of these soils can be expected to be angular due
to their very short transportation distance. Any
rounding in large fragments would be due almost entirely
to in situ weathering. Some physical and chemical
soils characteristics may be derived from parent
bedrock material in which the slide originated. For
example, soils derived over landslides or sinkholes
in the Eagle Valley Evaporite Sequence are likely to
exhibit high siilfate and salt content due to the
chemical nature of the parent material. Interpretations
of soils formed over Qcu areas should be made in
conjunction with Figure 8 , Bedrock Geology Map
A-72
-------
Denotes soils which have formed from colluvium, or
in situ weathering of bedrock materials. The coarse
portion of soils derived from colluvium can be ex-
pected to be angular, except for those fragments
which received rounding prior to lithification of the
bedrock materials. These soils are likely to show
chemical and physical characteristics which are
similar to those of the parent bedrock material.
For example, soil formed over limestone or dolomite
beds is likely to have an alkaline pH because of
high carbonate content; soil formed over shale is
likely to have fewer coarse fragments than soil
formed from sandstone or conglomerate. Interpretations
of soils formed over Qc areas should be made in
conjunction with Figure 8 , Bedrock Geology Map.
SOIL TYPE
Soil Type 1 CL-GC
PHYSICAL DESCRIPTION: This soil group includes unnamed fine
sandy loams, stony sandy loams, and stony clay loams, as de-
signated by the U. S. Soils Conservation Service. The most
frequent occurrence of this soil group is in the eastern portior
of the area on the steep mountainsides and terraces of Gore
Creek. The majority of them are deep and well-drained,
becoming increasingly stony with depth. These soils char-
acteristically have rapid or moderately rapid permeability
(2.0 to 20.0 inches/hour), and erosion hazard is slight to
moderate with their natural vegetation cover. The pH of these
soils ranges from 6.1 to 7.3 on northern exposures and from
6.6 to 8.4 on southern exposures.
WORKABILITY: Workable with most standard construction equip-
ment. Excessive stoniness can be a problem. A majority of
areas have more than thirty percent gravel, cobble or stone.
Material normally must be graded and sorted before use as filJ.
DRAINAGE/ERODIBILITY; Because of rapid permeability, runoff
and associated sheet erosion danger is slight to moderate.
Because of the high percentage of coarse fragments, these soils
tend to lose their cohesiveness when the natural root mat is
destroyed. After destruction of natural root mat, erosion
hazard becomes moderate to high.
SUITABILITY FOR;
Septic"Systems: Poor. Rapid permeability allows excess
seepage and danger of groundwater contamination. Large
stones hinder excavation.
Landfill; Poor. Due to seepage and large stones.
A-73
-------
Topsoil: Poor. Topsoil is thin and stony. Stoniness
increases with depth.
Foundations: Fair. Stones hinder excavation. Steel
corrosivity high. Concrete corrosivity low to moderate
in more alkaline areas.
Sand and Gravel: Poor to fair. Many areas too stony.
Some areas of poorly graded, very clayey gravel on
stream terraces.
Roadfill; Poor to fair. In many areas large stones
must be removed.
Irrigation: Poor. Limiting factors are high slope
angle, Stoniness and/or urban development. Areas which
might have been suitable for irrigation have already
been developed as urban or suburban/recreational lands.
Soil Type 2 CL-SC
PHYSICAL DESCRIPTION: This soil group consists of unnamed
sandy loams, sandy clay loams and clay loams, according to the
U. S. Soils Conservation Service. The soil group occurs mainly
on alluvial fans and stream terraces, and occasionally moun-
tain sideslopes. The soil includes occasional gravelly lenses.
Permeability is rapid to moderately rapid (2.0 to 20.0 inches/
hour) and soils are deep and well drained. Erosion hazard is
low to moderate because of vegetation cover and predominant
gentle slopes (less than 15%). The pH of these soils ranges
from 6.1 to 7.8.
WORKABILITY: Workable with most standard construction equip-
ment. Workability is generally good. Some slumping into
excavations may be encountered on slopes over 15%.
DRAINAGE/ERODIBILITY: Erosion hazard is low to moderate because
of gentle slopes, rapid infiltration rates, and heavy rootmats.
Erosion hazard would become ^moderate upon removal of natural
root mat.
SUITABILITY FOR;
Septic Systems; Fair to good. Becomes fair to poor
on slopes over 10%. Limiting factor is permeabilitv
rate and slope. Jf/
Landfill: Fair to poor. Becomes poor on slopes over
10%. Limiting factor is increasing seepage with in-
creasing slope.
Topsoil; Good. Becomes fair to poor with increasing
Stoniness and thinner soil on slopes over 10%.
A-74
-------
Foundations; Good to fair. Becomes fair to poor on
slopes over 10% and in occasional very stony lenses.
Moderate shrink swell and frost heaving may be encountered
Steel corrosivity is high. Concrete corrosivity is low-
Sand and Gravel: Very poor. Abundant fines.
Roadfill: Fair to poor. Limiting factors are shrink-
swell and frost action. Stoniness is a limiting factor
on slopes over 15%.
Irrigation: Fair to poor. Soils on gentle slopes may
be adequate for irrigation, but these soils lie almost
entirely in areas of urban or suburban developement.
Soil Type 3 CL-SC
PHYSICAL DESCRIPTION: This soil group includes the Libeg
Cobbly Loam, the Jerry Loam, the Ansel-Anvik Association, and
two unnamed loamy to sandy loamy soils, as designated by the
U. S. Soils Conservation Service. The most frequent occurrence
of these soils is in the western portion of the Sanitation
District, on mountain slopes under Spruce-Fir vegetation (Ansel-
Anvik) and on grassy rangeland slopes. The soils are generally
deep and well-drained and permeability is generally moderate
(0.6 to 2.0 inches/hour). Erosion hazard is slight to moderate
when the land retains its natural root cover. Soils are
generally neutral with pH values ranging from 6.1 to 7.8.
Color ranges from reddish browns in the Libeg Association to
grayish or yellowish-brown in the Ansel-Anvik Association.
WORKABILITY: Workable with most standard construction equip-
ment.Excessive stoniness can be a problem in some areas,
but is confined generally to fifty percent or less of these
soils. A high clay content in the topsoil layer may cause
surface layers to slump into excavations on slopes.
DRAINAGE/ERODIBILITY: Because of moderate permeability and
water transmission,the danger of sheet erosion is slight to
moderate. Because these soils tend to lose their cohesion
when natural root mat is destroyed, erosion danger is moderate
to high in barren areas.
SUITABILITY FOR:
Septic Systems; Fair to poor. Limiting factors are
stony areas, and areas of slope over 15%, with asso-
ciated greater permeability. In many level areas,
sufficient clay materials are available for liner.
Landfill; Fair to poor. Permeability is too great in
most areas, creating danger of groundwater contamination.
Stoniness hinders excavation in many areas.
A-75
-------
Topsoil: Poor to fair. Limiting factors are thin top-
soil layer, stoniness, excessive clays and slope.
Foundations: Good to fair. Large stones inhibit
excavation. Dangers of shrink-swell and frost heave
in surface clays is moderate. Suitability for founda-
tions becomes fair to poor on slopes over 15%. Clay
may slump into excavations on steep slopes. Corrosivity
of steel is high. Corrosivity of concrete is moderate.
Sand and Gravel; Poor. Excessive fines.
Roadfill: Poor to fair. Limiting factors are low
strength, large stones, frost action and shrink-swell.
Irrigation: Poor. Limiting factors are slope and
stoniness.
Soil Type 4 CL-SC
PHYSICAL DESCRIPTION: This soil type includes the Burnette-
Libeg Association and other unnamed loams and clay loams,
according to the U. S. Soil Conservation Service. The soil
group consists of sandy clay loams, clay loams and clays and
occurs on stream terraces and alluvial fans in the western
portion of the sanitation districts. The soils are generally
deep and well-drained. Permeability is moderate to slow.
Soils are formed from stream alluvium or glacial outwash, and
are generally neutral despite the gypsiferous bedrock which
usually underlies them at depth. Color is dark brown to
black loam.
WORKABILITY: Workable with most standard construction equip-
ment. Stoniness may be a problem in some areas. High clay
content in the topsoil layer may cause surface layers to slump
into excavations on slopes.
DRAINAGE/ERODIBILITY; Becuase of a generally good root mat,
low angle slopes and slow surface runoff, erosion hazard is
slight.
SUITABILITY FOR:
Septic Systems; Fair. Limiting factors are a slow
permeability rate and stoniness in some areas. Becomes
poor on slopes over 8%.
Landfill: Good to fair. Moderate permeability in some
areas may require a liner to guard against pollution
of groundwater through seepage. Large stones may inhibit
excavation and fill m some areas, especially on slopes
UV"iT O u •
A-76
-------
Topsoil: Poor. Limiting factors are high clay content
and thinness.
Foundations: Fair to poor. Limiting factors are low
strength, high shrink swell potential, frost heave,
and stoniness. Soils may slump into excavations.
Corrosivity of steel is high. Corrosivity of concrete
is low.
Sand and Gravel; Very poor. Excessive fines.
Roadfill: Poor to fair. Limiting factors are low
strength, frost action and shrink swell potential.
Irrigation: Fair to poor. Some irrigation and farming
has been performed historically, but most potentially
irrigable land is now committed to urban development.
Limiting factors are poor topsoil and stony areas.
Soil Type 5 GC-SC
PHYSICAL DESCRIPTION; This soil type includes the Zillman-
Unnamed cobbly loam complex and other unnamed gravelly loams,
according to the U. S. Soil Conservation Service. The soil
group consists of cobbly and sandy loams and occurs on stream
terraces and alluvial fans along the Eagle River where water
action has been sufficient to form well-graded, well-rounded
gravel deposits. The soil is moderately deep over cobble and
gravel, well-drained, and permeability is rapid. The pH is
generally neutral.
WORKABILITY: Can be worked with most standard construction
equipment.Excessive stoniness can be a problem.
DRAINAGE/ERODIBILITY; Surface runoff is slow and erosion hazaro
is slight because of a rapid permeability rate and usually
gentle slope.
SUITABILITY FOR:
Septic Systems; Poor. Large stones. Rapid permeability
may present a pollution hazard.
Landfill; Poor due to seepage and large stones.
Topsoil; Poor due to large stones.
Foundations; Poor to fair. Large stones are a limiting
factor. Cutbanks tend to cave. Becomes poor on slopes
exceeding 15%. Steel Corrosivity is high. Concrete
Corrosivity is moderate to low.
A-77
-------
Sand and Gravel: Good. Existing gravel pits occur
in this soil type.
Roadfill: Fair. Large stones are the limiting factor.
Irrigation; Very poor. Limiting factors are slope
and stoniness.
Soil Type 6 CL-SC, GC
PHYSICAL DESCRIPTION: This soil grdup includes unnamed sandy,
silty and channery loams and the Clapper Stony Loam, according
to U. S. Soils Conservation Service nomenclature. These
gypsiferous soils have formed over the Eagle Valley Evaporites.
Soils are used for rangeland. Permeability is moderate to
moderately rapid, runoff is moderate to high and erosion hazard
is high. Size gradation of the soil is usually sandy and
silty clay with some clayey sand, but some soil on breaks and
ridges is extremely stony. The pH of these soils is 7.4 to
8.4.
WORKABILITY: Workable with most standard construction equip-
ment. Piping, sinkholes and caving of soltition cavities may
present problems.
DRAINAGE /ERODIBILITY : Gypsiferous soils tend to be dry and
flaky with low available water capacity (0.10 to 0.17 inches/
hour) . Because of the dry, flaky nature of the soil, erosion
hazard is high, despite moderate to moderately rapid infil-
tration-rates. Collapse of solution cavities can cause dis-
ruption of drainage patterns and resultant high erosion danger.
Sediment yield risk when vegetation cover is removed becomes
very high.
SUITABILITY FOR:
Septic Systems: Good. Care should be taken to avoid
sinkholes or solution cavities. Becomes fair to poor
on slopes over 8%.
Landfill: Poor. Permeability rates create hazard of
groundwater pollution.
Topsoil; Poor. Topsoil is thin and stony. Alkalinity
may be a borderline problem in some areas.
Foundations: Fair to good. Cutbanks tend to cave be-
6 ° low.S011 ^rength. Some frost heave may occur
o '
Sand and Gravel; Very poor
A-78
-------
Roadfill: Fair to poor. Soils exhibit low strength.
Some frost heave may occur.
Irrigation: Very poor. Limiting factors are alkalinity,
high gypsum content and slope.
Soil Type 7 GM-ML
PHYSICAL DESCRIPTION: This is deep, poorly-drained, sandy
loam with lenses of stony loam, loamy sand, sand, gravel and
areas of marshland rich in organic content. No U. S. Soils
Conservation Service nomenclature has been given this soil
type. This soil type occurs throughout the Sanitation District
on the modern floodplain of the Eagle River and Gore Creek.
Permeability is rapid, but a high water table throughout the
year inhibits soil drainage. The pH is generally neutral,
except in areas of high organic content where pH is slightly
acid.
WORKABILITY; Workable with most standard construction equip-
ment. Pumping may be required due to high water table. Grave]
and boulder content increases to more than 35% percent below
25 inches.
DRAINAGE/ERODIBILITY: Erosion hazard is generally low because
of low slope angle,except during periods of flood when hazard
of stream bank erosion is high. Flood hazard is seasonal.
SUITABILITY FOR:
Septic Systems: Very poor. High water table would be
severe groundwater pollution hazard.
Landfill: Very poor. High water table would be severe
groundwater pollution hazard.
Topsoil: Very poor. Poor drainage and large stones
are limiting factors.
Foundations: Very poor. High water table and flood
hazard. S~teel corrosivity is high. Concrete corrosivity
is moderate.
Sand and Gravel; Fair to good. Gravel pits would have
to be pumped due to high water table.
Roadfill: Fair to poor. Wetness and large stones are
limiting factors.
Irrigation; Very poor. Poor drainage and stoniness
are limiting factors.
A-79
-------
Soil Type 8 ROCKLAND
PHYSICAL DESCRIPTION: This unit consits of rough broken land,
stony land and rocJcland, according to the U. S. Soil Conservation
Service. There is very little actual soil present. Much of
the land is broken by intermittent drainage channels, and sparse
vegetation may grow in a few more favorable areas. Rockland
areas occur in the center portions of the sanitation districts
on very steep talus and wasterock slopes. Soils, where present,
are very shallow and permeability is very slow because bedrock
is at or near the surface. Because more than half of these
areas consist of exposed bedrock, erosion hazard is slight and
runoff is high.
WORKABILITY: Ripping or blasting may be necessary in many areas,
depending upon quality of bedrock. In most areas, must be
crushed and mixed with binder for compaction.
DRAINAGE/ERODIBILITY; Runoff is high due to minimal permeability
of bedrock. Erosion hazard is very low due to hardness of
bedrock and absence of soil in most areas.
SUITABILITY FOR:
Septic~Systerns: Very poor. Lack of soil and resultant
very slow permeability is unsuitable.
Landfill; Very poor. Bedrock fractures near surface
present hazard of groundwater contamination. Excavation
would be very difficult in almost all areas.
Topsoil: Very poor. Thin to nonexistent in most areas.
Foundations: Very poor. Ripping or blasting would be
required in most areas.
Sand and Gravel; Very poor. Fragments too large or
solid bedrock.
Roadfill: Very poor. Fragments too large or solid
bedrock.
Irrigation: Very poor. No soil.
SOURCE: Appendix K and Figure 9 , Map of Soils and Surficial
Deposits, was compiled by Judi C. Culver of Charles S.
Robinson s Associates, Inc. at the request of Camp
Dresser & McKee. The information was compiled in
February, 1976, from existing literature, aerial
photography, and from field investigations made by the
U. S. Soils Conservation Service.
A-80
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JTPQIDIX L
AVERAGE AMD EXTREME DISCHARGES FOR UEGS ST/^IWIS LOCATED Ot; THE EAGLE RIVER AIID ITS TRIBUTARIES
STATION
Eagle River at Fed Cliff
Wearyman Creek near Red Cliff
Turkey Creek near Red Cliff
lloiestake Creek near Red Cliff
Cross Creek near Minturn
Gore Creek (upper station near Minturn)
Black Gore Creek near Minturn
j»
i Clack Gore Creek near Vail
00
I-1
Bighorn Creek near Minturn
Fitkin Creek near Minturn
Booth Creek near Minturn
Gore Creek at Vail
Middle Creek near Minturn
Red Sandstone Creek near Minturn
Beaver Creek at Avon
Eagle River below Gypsum
ADIAGE
70. CO
8.78
23.90
58.30
33.50
14.30
11.80
19. CO
4.37
5.39
6.03
55.00
5.97
7.27
15.70
944.00
YEARS
OF
DATA
451
10
12
30l
141
201
201
1
11
P1
10
1
]0
11
Very
Fragmentary
IEAI1
AtJNUAL
cfs'
49.90
8.47
22.10
38. 807
51.30
28.10
16.50
34.00
8.14
10.00
11.30
106.00
5.59
8.61
569.00
DISCHARGE
Ac-ft/yr3
36,150
6,140
16,010
28,1107
37,170
20,360
11,950
12,414
5,900
7,240
8,190
76,870
4,050
6,380
412,200
PERIOD OF RECORD EXTREMES
Maxinutr. Mininum
cfs Date4 cfs Date5
1,010
140
515
1,300
754
588
365
340
225
126
182
1,260
116
207
122
6,580
6-05-65
6-18-65
6-17-65
6-24-1G
6-30-57
6-10-52
6-07-52
5-30-74
6-10-73
6-24-71
6-21-66
5-29-74
6-20-74
6-10-73
5-29-74
6-11-52
1.00
0.30
ND6
0.60
0.10
1.40
0.90
2.80
0.10
0.24
0.20
4.70
No Flov-
0.20
1.50
110.00
10-15-17
02-21-67
—
01-25-15
12-27-62 to
02-27-66 and
to 03-09-66
02-22-68 and
02-27-76
02-08-67
10-29-72 and
02-08-67 and
02-24-74
Several
01-30-70
12-31-62
03-03-66
1-30-70
11-01-72
01-29-70
08-09-11
02-21-55, 02-03-56,
12-26-62 and 12-27-62
1 234
^Indicates interrupted data accumulation; ^Cubic feet per second;7 Acre-feet per year; Maximum flood flow recorded - instantaneous
Minimum daily average flow for 24 hours; ND = Not determined; Based on 8 years data after completion of Homestake Diversion Tunnel
SOURCE: 1974 Water Resources Data for Colorado, Part 1, U.S. Geological Survey
-------
APPENDIX M
SUMMARY OF CURRENT
DISCHARGE PERMIT LIMITATIONS
r>. r- r-i
9\ r- (0
^ ,H 0} O
r» r~- r~ ^ "H
«* •"" ^ ""• _T -w 51
,_! ff\ ON r^ r-l « Js >>
,H ,H ON ^H C 4J
t-H ^ « ^^
-1 ^ ±T §•
i-l rH • S rH B
>. i-4 «-J 3 O 4J
M >. >» -) u a
3 t-H IH >^ a> at
^ 33 ^HMMOQ
«=j H, 3 O 0) C
fli i-j «w 4J -H >,
(j lj ID 0) IM M «
O 0) W >-c JD (fl 5
u-i *J O > JC
u u-iu-i w . . a) oc
o (BID u-tu-iiuw ^
J3 nj u-i u_i M X
. i-l i-l U
O O . _| ,_( 1-5
W C/3 ^H -H U U O
> >lH lHt3T33»H
U U(Q 03 Q) 0) QJ O
3 3> >OSB!aU
BOD - 30 day avg. (mg/1) 30 30 30 30 30 30 -
BOD - 7 day avg. (mg/1) 45 45 45 45 45 45 -
SS - 30 day avg. (mg/1) 30 30 30 30 30 30 30 30
SS - 7 day avg. (mg/1) 45 45 45 45 45 45 - 45
Fecal Coliforms
-30 day avg. (no./lOO ml) - 6000 - 6000 -
-7 day avg. (no./lOO ml) 5000 12000 5000 12000 -
Total resid. chlorine (mg/1) .1 .05 .5 .05 .2 .2 -
Ammonia - Dec.-Jul. (kg/day) 116 116 - -
Ammonia - Aug.-Nov. (kg/day) 50C50C-
Oil and grease (mg/1) 10 10 10 10 10 10 - 10
Zinc (mg/1) ___ ___!_
Iron (mg/1) - -- ___2
Soluble iron (mg/1) - - - - __ ^5
Cyanide (mg/1) - - _ _025
Lead (mg/1) - -_ ___ >1_
Manganese (mg/1) - - - _ __ 2.5-
Dissolved Aluminum
-30 day avg. (mg/1) - - _ 1>0
-7 day avg. (mg/1) - - _ 5
a daily limit
b 245 Ib/day
c 110 Ib/day
A-82
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APPENDIX N
Sewerage System Improvements for Red Cliff
The background of the Red Cliff system has been included in
Section VI. A. of this report. A study and report was recently
prepared by Wright-McLaughlin Engineers on the sanitary sewer
and sewage treatment system in Red Cliff. The report described
the present state of the system and recommended that certain
corrective measures be taken to upgrade its performance and
efficiency. The Facilities Plan engineering consultant (M & 3)
has determined that the recommendations made in the report
represent a reasonable and feasible solution for improving the
system, and COM concurs; therefore, this analysis will address
the improvement plan prescribed in the Wright-McLaughlin repot '..
Summary of Existing__Problems
The existing sewage collection and outfall system is subject
to severe infiltration problems, which have been attributed large 'y
to substandard construction and inadequate inspection. In
addition, water service lines are bled into the sewers in orde"
to prevent line freezing in the winter. As a result of this
infiltration and inflow, sewage flows at the treatment plant
are 3 to 4 times the amounts that would normally be expected
from the known customers. It has been concluded that the sewer
system is of little value in its present state.
The existing treatment plant is a package unit which operates on
the contact-stabilization activated sludge process, and is de-
signed to treat 70,000 gpd. Due to the high hydraulic loadings,
the plant is not able to operate properly, and in fact, much of
the reduction in discharged pollutant levels from normal dome:; t±'.-
sewage can be attributed largely to dilution by the infiltration-
inflow water. In addition, the plant is not designed with con-
sideration for cold temperatures, adverse weather, operation
simplicity, and safety.
Recommended Improvements
It is recommended that the existing sewer system undergo a
rigorous rehabilitation program. Most of the lines must either
be removed and replaced, relined with inserted polyethylene
sleeves, or pressure grouted. Also, bleeder flows should be
eliminated from the sewers and routed directly to streams or
special bleeder service lines. Infiltration/inflow would not
be completely eliminated, but flows would be reduced to a range
between 60,000 and 100,000 gpd. The treatment plant is of
adequate size for the present Red Cliff population as well as
future projections through the year 1995. It is recommended
that the facility be modified to operate on the conventional
activated sludge principle, and that certain other improvements
A-83
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be made, includinq grit removal, flow equalization, filtration,
and additional capability for disinfection and sludge handling
and disposal. Also the plant should be completely enclosed and
handrails installed around the tanks. Improvements recommended
are primarily in the interest of increased reliability, opera-
bility, minimum cost, and attaining an acceptable level of
sewage treatment.
Treatment System Evaluation
Discharge Requirements: The Discharge Permit currently in effect
will expire on September 30, 1976. The current permit is
summarized in the following table:
30 day Avq. 7 day Avq. Daily Maximum
BOD 30 mg/1 45 mg/1 60 mg/1
Suspended Solids 30 mg/1 45 mg/1 60 mg/1
Coliforms 200/100 ml 400/100 ml
Residual Chlorine .2 mg/1
It is expected that most of these criteria will not change
appreciably when the permit is renewed. Although highly restric-
tive in-stream chlorine residual limitations are currently
proposed, a discharge of 0.2 mg/1 should not cause the limits
to be exceeded. Since this plant is small, its effect on stream
waste load allocations will be minimal and it does not seem
likely that restrictive limitations on ammonia or nutrient dis-
charge will appear on the new permit.
Primary Treatment: Relocating the bar screen inside a building
will allow better access for cleaning during the winter. A
grit chamber is highly beneficial, particularly when primary
settling is not provided. Grit removal protects pumps from
abrasion and prevents grit buildup in the aeration basins, which
can cause displacement of mixed liquor and reduce plant efficiency.
Primary clarification customarily precedes aeration when the
conventional activated sludge process is used, but as has been
previously pointed out, may not be necessary when the wastewater
is primarily domestic, does not contain excessive grease, and
grit removal is provided. Conventional treatment is used suc-
cessfully in Colorado at many locations without primary settling
Even though the plant will be operating in the conventional mode,
it should be designed to require minimal attention. Exclusion of
primary clarification will eliminate the production of primary
sludge and the need for associated equipment, handling processes,
and operator attention.
Secondary Treatment. The most ideal modification of the
activated sludge process for a plant of this size would be
the extended aeration concept, where the organic sludge is self-
consuming, and only a small amount of inert sludge must be
periodically wasted. However, it has been found that the
existing plant cannot be converted to this process without
greatly overloading the secondary clarifier. Thus, conventional
A-84
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aeration is the most feasible process, as recommended. It
has been determined that, due to previous overdesign of the
aeration tanks, the tankage appears large enough for conventional
operation. The existing process (contact-stabilization)
theoretically requires less tankage than the conventional mode,
but is more difficult to operate, particularly for the way
this plant is constructed, is less reliable, and is usually
only recommended as a temporary back-up process when extra
contact tanks will be used as aeration chambers for conventional
operation. Secondary settling will be provided with the
existing clarifier. It is imperative that provisions be made
for continual sludge wastage, since large volumes of organic
sludge are generated with conventional operation. The poor
hydraulic characteristics of the settling tank may cause some
sludge washout during peak loading periods, especially if proper
sludge wastage control is not provided.
Sludge Handling. From 70 to 120 Ib. of dry sludge will be
produced per day by this plant (a probable wet sludge volume
of 1700 to 2800 gallons per day -gpd). Aerobic digestion is
recommended for sludge stabilization, and should reduce the
waste volume below 600 gpd. This process requires little
attention and is not susceptible to upsets. The sludge
produced is easily dewatered, and excellent for agricultural
application. Power costs are incurred for aeration, and no
useful byproduct, such as methane gas, is produced. The
simplest technique for sludge drying is open air beds, such
as now exist at the plant. Additional bed capacity will
probably be needed to accommodate the sludge load and the
beds must be covered to allow for winter drying. The
alternative to covering the beds would be sludge holding tanks
or mechanical dewatering, both of which would be expensive.
Dried sludge must be periodically trucked to a landfill site,
and could be applied agriculturally if any demand existed.
Chlorination. As discussed elsewhere in this report, it is
difficult to attain a high level of disinfection with chlorine
and at the same time discharge a low residual. However, the
recommended 10,000 gallon backwash tank will provide 4 hours of
contact time, which should be sufficient unless the allowable
residual discharge limitation is substantially reduced.
Equalization. This process is highly desirable where plant
inflows fluctuate greatly, and is also usually recommended
to precede filtration, since gravity filters do not operate
well under variable flow rates.
Sewage Filtration. In Colorado, sewage plants smaller than .5
mgd must provide a polishing process following biological
treatment, since such plants are subject to more exaggerated
loadings and consequently are more easily upset. This polishing
process can usually be provided with a shallow aerobic pond.
However, in mountainous areas where space is not available,
a gravity sand filter provides an excellent alternative.
Most BOD in secondary effluent is in the suspended form, and
A-85
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thus filtration will substantially .reduce BOD and suspended
solids discharge to the receiving stream, making the discharge
permit limitations easily attained. Chemical aids are usually
needed, and recycled filter backwash water can increase
hydraulic loading on the plant by as much as 10 percent.
Ammonia. As stated elsewhere, it is unlikely that ammonia
reduction will be required at the Red Cliff Plant. With minimal
uptake in the secondarv treatment process, a maximum amount
of 10 Ib. per day would be discharged to the Eagle River. This
would probably not affect the allowable ammonia discharge at
downstream plants, due to in-stream oxidation and stripping.
Ammonia removal at Red Cliff would be expensive, require
greater operator attention, and in general would be unrealistic
for a plant of this size.
Cold Weather Effects. As discussed elsewhere in this report,
cold temperatures severely retard the biological reactions
which occur in secondary sewage treatment and aerobic digestion.
Also, the oxygen transfer capacity of aeration systems is
reduced, and solids settling is hindered. In areas experiencing
harsh climates, such as Red Cliff, appropriate design measures
must be taken to compensate for these effects. It is absolutely
necessary that all processes be enclosed, preferably in a heated
building. Other measures include increasing process detention
times and over-sizing aeration equipment. The detention times,
aeration systems, and other improvements that will be provided
with the recommended system should be sufficient to insure
adequate treatment at low temperatures. It is likely that,
even if enclosed, the efficiency of the aerobic digester will
be reduced somewhat during the winter.
Potential Environmental Impacts of the Recommended Plan
Red Cliff occupies portions of a very confined valley floor
near the confluence of the Eagle River and Turkey Creek.
Because of the narrowness of the valley floor, most of the
terrestrial and aquatic habitat within the area has become
greatly altered due to human activity. The proposed plan to
rehabilitate the Red Cliff sanitary sewage system will have
little impact on the ecology of the area. Primary impacts will
be temporary changes in water quality due to construction.
Vegetation and Wildlife. Natural vegetation and wildlife is
essentially non-existent within the confines of the area which
will be disturbed by construction activity. Adverse construc-
tion impacts upon local vegetation and wildlife will, therefore,
be minimal. Since population in this area is expected to
decline in the future, there will be no secondary adverse
effects on local wildlife and vegetation normally associated
with increased human activity.
A-86
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Biology* Construction associated with the repair
and replacement of sewer interceptor lines and the sewage
treatment plant improvements may result in a number of
potentially adverse effects on the aquatic biota, which are
similar to those described for the Upper Eagle Valley sanitation
district.
Operation Effects. Implementation of the operational phase
of the proposed rehabilitation plan will greatly reduce
(1) the volume of total liquid flowing from the plant to the
Upper Eagle River system by reduction of infiltration/inflow
waters, and (2) the volume of untreated sewage pollutants
discharged to the river since most pollutants will be oxidized
or removed as sludge. The net effect will be a decrease in
water quantity but an increase in water quality, which will
be beneficial to the areas' aquatic biota.
A-87
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141 U.S. Environmental Protection Agency. Compilation of Air
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142 U.S. Environmental Protection Agency. Data from Carbon
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143 U.S. Environmental Protection Agency, Draft Environmental
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148 U.S. Environmental Protection Agency. Proposed Criteria
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149 U.S. Environmental Protection Agency- Storet Data
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150 U.S. Forest Service, Holy Cross Ranger District, Environ-
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153 U.S. Geological Survey- Water Resources Data for Colorado.
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154 U.S. Geological Survey. Water Resources Data for Colorado.
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155 U.S. Public Health Service. Drinking Water Standards, U.S.
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156 U.S. Public Law 91-190, National Environmental Policy Act
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157 U.S. Public Law 92-500, Amendments to the Federal Water
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158 University of Colorado. Minturn Master Plan. 1975
159 University of Colorado, Department of Environmental Design.
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160 Vail Associates and the U.S. Forest Service. "Beaver Creek
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161 Vamos, R. and R. Tasnadi. "Ammonia Poisoning in Carp",
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16;
r Quality Control Commission (Colorado), letter
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164 Weber, W.A. Rocky Mountain Flora. Colorado Associated
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165 Wentz, Dennis A. Effect of Mine Drainage on the Quality
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166 Willingham, William T. Ammonia Toxicity and Its Removal
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169 Woodward-Envicon, Inc. Draft Environmental Overview
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170 Wright-McLaughlin Engineers, Sanitary Sewage System
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171 Wuerthele, Mark. An Investigation of Ammonia Levels in
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172 Wuerthele, Mark, Water Quality Survey of the Eagle River
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BIBLIOGRAPHY
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173 Allred, Ron. President, Benchmark. January-March, 1976.
174 Bellm, Harold. Mayor of Minturn, Colorado. January, 1976.
175 Blair, Michael and Steve Isolm. Eagle County Planning
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176 Brown, Byron. Byron Brown Real Estate. January, 1976.
177 Browning, Ed. United States Forest Service, Denver, Colorado.
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179 Dietrich, John and Rod Libby. Vail Run Real Estate.
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185 Kelton, Art. Kelton Real Estate and Eagle-Vail, Vice
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186 Lament, Jim. Town of Vail, Community Resources. March, 1976.
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188 Manzanres, Robert. Town Manager, Minturn and Assistant
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189 Milliken, Gordon. Denver Research Institute. December, 1975 •
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190 Minger, Terry. Town Manager, Town of Vail. January-
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191 Mott, David. Beaver Creek Project Director. January-
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193 Nunn, Ernie. United States Forest Service District Ranger,
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199 Selby, Jeffrey. Commercial developer, Vail, Colorado.
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