Draft Environmental Impact Statement
Proposed Water Qu
Management Plan
Blue River Basin
Summit County Colorado
United States Environmental Protection Agency
Region VIII, Denver, Colorado
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Draft
Environmental
Impact
Statement
Water Quality
Management
Plan
for the
Blue River Basin
Summit County,
Colorado
United States
Environmenta
Protection Agency
Region VIII
186O Lincoln St.
Denver, Qtfforado
John A. Green
Regional Administrator
FEB_
Date
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SUMMARY SHEET
ENVIRONMENTAL IMPACT STATEMENT
x) DRAFT
) FINAL
Prepared by the U.S. Environmental Protection Agen-
cy, Rocky-Mountain - Prairie Region, Region VIII,
Denver, Colorado
A. Type of Action: Administrative
B. Brief Description of Proposa]
The Federal Water Pollution Control Act requires
the states to submit basin-wide plans to EPA for
managing water quality. Under Section 3(c) of the
1965 version of the Act, the State of Colorado has
submitted a Water Quality Management Plan for the
Blue River Basin in Colorado. EPA's approval of
the plan is the subject of this environmental im-
pact statement (EIS).
The plan recommends a structural arrangement of both
secondary and advanced wastewater treatment facili-
ties to provide sewage treatment service to the ba-
sin. The recommended project is shown on Figure 12
(page 70) as Alternate 6. The type of treatment re-
quired, and the capacities of the plants were deter-
mined on the basis of waste load allocations which
have been made for Dillon Reservoir, considered to
be the most sensitive receiving water in the basin.
Controlling nutrient inputs to Dillon Reservoir, and
the implications of implementing the waste load al-
locations, are the major issues in this EIS.
C. Alternatives Considered
In addition to considering various structural ar-
rangements of domestic wastewater treatment facili-
ties in the basin, the plan has considered land
application of treated sewage effluent. Most of
the structural alternatives considered and shown
in Figure 12 would provide some diversion of wastes
away from Dillon Reservoir.
D. Environmental Impacts
Implementation of the major features of the proposed
plan would provide short-term benefits to water
quality, especially in Dillon Reservoir. Long-term
effects on water quality are more uncertain, since
the plan does not recommend the complete elimination
of waste discharges into the reservoir. In addition,
as development proceeds in the basin, amounts of non-
point pollutants introduced into the system are ex-
pected to increase.
If the waste load allocations for Dillon Reservoir
are enforced, full implementation of them could, to
some extent, limit growth in some parts of the ba-
sin.
Secondary environmental effects of the plan are not
expected to be significant, since the planning per-
iod extends only to 1977. The plan does not commit
the construction of actual treatment plants, only
makes recommendations concerning their location and
level of treatment. If secondary effects occur, they
would be linked to the waste load allocations, since
some growth in the basin may be dependent upon their
implementation. If the technological capabilities
of wastewater treatment plants in the basin are suf-
ficient to assure compliance with the waste load al-
locations, then the allocations would not limit growth.
II
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Full implementation of the proposed plan would in-
volve direct environmental impacts on water quality,
air quality, noise, aesthetics, and biological sys-
tems in the immediate vicinity of construction. As
the implementation of the plan may guide land use
practices in the basin, adverse environmental impacts
could result if planning efforts are not coordinated.
Sanitation Districts:
Breckenridge Sanitation District
Dillon-Silverthorne Joint Sewer Authority
Frisco Sanitation District
E. Dillon Water and Sanitation District
Copper Mountain Water and Sanitation Dist.
Buffalo Mountain Water and Sanitation Dist.
Ski Areas:
Breckenridge
Copper Mountain
Keystone
A-Basin
Most environmental impacts, especially those associa-
ted with water quality, will be mitigated as the
"208 Plan" for the area is developed and implemen-
ted. Further, the direct and secondary environmen-
tal effects of constructing and operating the treat-
ment plants recommended in this plan will be assessed
in detail as required by EPA regulations for providing state Agencies:
Federal financial assistance to municipalities for State Clearinghouse/Division of Planning
the construction of sewage treatment plants. Colorado Water Pollution Control Division
Colorado Air Pollution Control Division
E. Dates Statement made avail able t.n TED and the Colorado State Board of Land Commissioners
general_p_u_b1 ic: Colorado State Land Use Commission
Colorado Division of Highways
Draft: Colorado Division of Wildlife
Final:
Federal Agencies:
F. Distribution U.S. Forest Service (Regional Forester and
The draft EIS is being provided to the following: Dillon District)
Federal Highway Administration
Local Agencies: U.S. Bureau of Reclamation
Summit County Commissioners Bureau of Outdoor Recreation
Summit County Planning Department U.S. Fish and Wildlife Service
Incorporated Areas: Bureau of Land Management
Breckenridge Field Representative, Office of the Secretary
Frisco of the Interior
Silverthorne
Dillon Others:
Northwest Colorado Council of-Governments Summit Citizens Association
Colorado Open Space Council, Inc.
Trout Unlimited
III
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National Wildlife Federation
Rocky Mountain Center on Environment
Denver Water Board
Colorado Ski Country USA
Fredric R. Harris & Assoc.
R. Keith Hook and Assoc.
Wright-Mclaughlin Engineers
Weiner & Associates
Mr. Tom Smart, Esq.
Denver Post
Rocky Mountain News
Summit County Journal
Summit Historical Society
Black & Veatch Engineers
Rick Logsdon
6. Acknow!edqements:
This EIS was prepared using materials from the pro-
posed plan, and an assessment of the plan which was
prepared for EPA by Fredric R. Harris and Associates
of Jacksonville, Florida.
The Summit County Planning Department was very help-
ful during the preparation of the EIS.
EIS design and graphics by Richard Logsdon, Denver,
Colorado.
IV
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LIST OF TABLES
Name
1. Characteristics of Summit
County Soil Associations
2. Streamflow Data
3. Basic Reservoir Data
Blue River Basin
4. Water Allocations
5. Proposed Future Diversions
to Dillon Reservoir
6. Water Quality Data, Major
Streams of the Blue River Basin
7. Dillon Reservoir Water
Quality Survey
8. Representative Effluent Data,
Wastewater Treatment Plants,
Summit County
Page
16
18
18
21
21
26-27
29
36
9. Waste Load Allocation of Phosphorus 36
to Dillon Reservoir
10. Waste Load Allocation of Phosphorus
to Dischargers Tributary to Dillon 38
Reservoir, & Resultant Reservoir
Concentrations
11. Projected Full-Time Residents
of Summit County
47
(Continued)
Name
12. Projected Seasonal Resident
Population in Summit County
13. Peak Seasonal Populations
Blue River Basin
14. Annual Average Populations
and Wastewater Flows Used
in Reservoir Loading Analysis
15. Summit County Land Ownership
16. Use of Summit County Ski Areas
17. Comparison Sheet ~ Structural
Alternatives
18. Cost Comparison ~ Structural
Alternatives
Page
49
50
53
56
64
74-75
76
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LIST OF FIGURES
Name Page
1. Summit County, Colorado --
Area Location 4
2. Major Features Summit County 5
3. Average Monthly Precipitation
and Temperature at Dillon 12
4. General Soil Associations 14-15
5. Dillon Reservoir & Vicinity 20
6. Denver Water Board Projects 22
7. Dillon Reservoir -- Outdoor
Recreation Facilities 24
8. Green Mountain Reservoir 25
9. Wastewater Treatment Facilities
Location 1975 32-33
10. Population Projections
Summit County 51
11. Land Use 54-55
12. Alternate Strategies 70-72
VI
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TABLE OF CONTENTS
(Continued)
Title
Page
Title
Page
Summary Sheet 11
Distribution List 111
List of Tables v
List of Figures vi
I. Introduction 1
II. Description of the Environment 11
Climate 11
Soils 11
Geology 13
Hydrology 17
Water Quality & Wastewater Treatment 23
Air Quality 42
Biological Resources 44
Population 46
Land Use 52
Historical & Archaeological Resources 62
Transportation 63
Recreational Resources 63
Sensitive Environmental Areas 65
III. Alternatives 69
Objectives 69
Description of Alternatives 69
IV. Proposed Plan
V. Environmental Impacts
VI. Adverse Impacts Which Cannot
Be Avoided
VII. Relationship Between Local
Short-Term Uses versus Long-
Term Productivity
VIII. Irreversible and Irretrievable
Commitments of Resources
Bibliography
Appendix
81
85
91
93
95
97
99
A. Colorado State Water
Quality Standards
B. Waste Load Allocations
C. Summit County Regulations for
Individual Sewage Disposal
D. EPA Discussion Paper on
Phosphorus & Waste Loads
E. Excerpts from NPDES Permits
F. Example of How Waste Load
Allocations Work
G. Detailed Description of
Structural Alternatives
VII
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Introduction
The Federal Water Pollution Control Act Amendments
of 1972 established a national goal of water qual-
ity suitable for fishing and swimming by mid-1983,
and set forth actions which will be required by
the Federal government and the states to reach that
goal. A major element in reaching this goal is
the development of "basin plans", described in
Section 303(e) of the Act. Prior to the Act's
amendments of 1972, the 1965 version (Section 3
(c)) established a system of providing Federal
funds to state governments for basin plan develop-
ment.
Summit County, Colorado, acting through its Board
of County Commissioners,-has adopted some of the
highest wastewater effluent standards in the na-
tion. Summit County, the Colorado Department of
Health, and the Environmental Protection Agency
have recognized that special attention is requir-
ed in the Blue River Basin to assure that the
water quality of stream, rivers, lakes and reser-
voirs is maintained or improved. In compliance
with the Federal Water Pollution Control Act as
amended, the proposed Water Quality Management
Plan for the Blue River Hydrologic Basin is an
important step towards reaching that goal.
A basic idea behind sound water quality management
planning is to avoid the proliferation of waste-
water treatment facilities which were conceived in
a vacuum, and which may not, when analyzed on a
basin-wide scale, provide the amount of water
quality improvement which is necessary for pro-
1
tection of the resource. A well-prepared basin
plan should provide the information the state needs
to make centralized, coordinated water quality
decisions which take into account overall pol-
icies and programs of the state and local govern-
ments, including those for land use and other re-
lated natural resources.
In mid-1973, the Summit County Board of County
Commissioners adopted an interim water quality
management plan which set forth guidelines to be
used in the immediate future for evaluation of
wastewater treatment facilities expected to be
constructed within the County. The interim plan
was prepared with the assistance of the Colorado
Water Quality Control Division of the State Health
Department.
On April 10, 1973, the State of Colorado was
awarded a Federal grant of $15,612, fifty percent
of the amount estimated necessary to develop a
basin plan for the Blue River Hydrologic Basin.
The State hired the Colorado Springs firm of R.
Keith Hook and Associates, Inc., to conduct the
studies needed to complete the plan. The final
version of the plan was submitted to EPA by former
Governor Vanderhoof on December 3, 1974. EPA's ap-
proval of the plan is the subject of this environ-
mental impact statement (EIS).
The components of any approved water quality man-
agement plan will be implemented through the more
detailed planning process required before Federal
assistance funds are used to help finance individual
treatment facilities. This "facilities planning
process" uses the basin plan as a framework for
treatment plant design. In addition, the discharge
permit program (NPDES), which is now administered
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by the State of Colorado, will also guide the design
of individual facilities.
Before we go any further, it must be stressed:
hjasin plan is a flexible,. working document designed
to help cope with water pollution nrnhlems nn a
basin-wide scale. As the water quality goals of
the basin change, or as new studies or technolog-
ical advances indicate a need to modify the details
of a basin plan, it will be done.
LOCATION OF PROPOSED ACTION
The Blue River Basin and Summit County are in
north-central Colorado on the western slope of the
Continental Divide (Figure 1). The river basin
has an area of approximately 182,340 hectares (704
square miles). The boundaries of the basin are
essentially congruent with those of Summit County,
making the area a nearly ideal water quality man-
agement planning unit. The basin and Summit County
are oriented in a generally north-south direction,
with the Blue River flowing northerly through the
county. A small portion of the Blue River Hydro-
logic Basin lies to the north in adjacent Grand
County. Figure 2 shows the major political and
natural features of the county, including the two
major highways, Interstate 70 and State Highway 9.
For the purposes of the water quality management
planning effort, the county and the basin have been
divided into four sub-basins. The Upper Blue River,
Snake River, and Tenmile Creek Sub-basins are
known collectively as the Dillon Reservoir Water-
shed, and comprise essentially the southern half
of the entire basin. The northern half of the
basin (below Dillon Reservoir) is known as the
Lower Blue River Sub-basin. For simplicity, the
proposed water quality management plan and this EIS
use "Blue River Basin", "basin", and "Summit County"
interchangeably.
Because of its proximity to Denver and otner
heavily populated Front Range areas of Colorado
(only about 60 miles via Interstate 70), Summit
County is extensively used as a recreation area.
Several of Colorado's most popular winter sports
sites are located in the county, and Dillon
Reservoir attracts many Denver area residents for
flat-water recreation in the summer. In addition,
the Arapaho National Forest offers opportunities
for camping, hiking, and wilderness experiences.
WATER QUALITY OBJECTIVES
Objectives for the quality of water in the streams,
rivers, and reservoirs of the Blue River basin are
governed by three major institutional considerations:
1) water quality standards which have been adopted
by the State of Colorado and approved by EPA, and
8
2) the fact that Dillon Reservoir is a major storage
facility for the Denver Metropolitan area's drinking
water, and 3) water quality criteria which have been
adopted by Summit County. Added to these is the fact
that the rapid growth of the county and its unique
ecological setting make the waters of the basin
particularly sensitive to the pressures placed on
them. Water quality standards and stream classifi-
cations for the State of Colorado were adopted by the
Colorado Department of Health on January 15, 1974,
and became effective June 19, 1974. Under the State's
classification system, the Blue River (including
Dillon Reservoir; has been classified Class BI , mean-
ing that the waters are suitable for all uses,
including a cold-water fishery, but except primary
recreation, such as swimming and water skiing. Green
Mountain Reservoir has been classified as AI, which
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Summit County, Colorado
Area Location
Figure 1
Project Location
Figure 2
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is suitable for all purposes including cold-water
fishery and primary body contact recreation.
Excerpts from the water quality standards are
reproduced in Appendix "A".
For the purposes of evaluating and reducing the
discharge of wastewaters into waters of the State,
the Blue River has also been classified as a "water
quality limited" stream segment. This means that
the river is not likely to meet water quality
standards (or already exceeds them), even though
the "best practicable control technology" is applied
to reduce pollution from industrial sources, or
secondary treatment (see "Common Environmental
Terms") is applied to municipal sources. The Blue
River has trouble complying with the following
portion of the Colorado standards, which says that
the waters of the State shall be:
free from substances and conditions
or combinations thereof attributable
to municipal, industrial, or other
discharges or agricultural practices
in concentrations which produce un-
desirable aquatic life.
Based on a recent study (Environmental Protection
Agency, 1973), the "undesirable aquatic life" is
in the form of diatom "blooms" which are nourished
by the relatively high concentrations of nutrients,
especially phosphorus, found in Dillon Reservoir
and the Blue River. A major objective of a water
quality management program for the Blue River Basin,
then, is to reduce the levels of undesirable aquatic
life through a reduction in the amount of nutrients
discharged in wastewat.ers throughout the hasip.
Since secondary treatment of municipal wastewaters
in the basin will not be sufficient to bring the
river into compliance with standards, more stringent
treatment requirements will be imposed via the NPDES
discharge permit program, and on the basis of "waste
load allocations" which have been made for the river.
Hopefully, this program of mapping out water quality
problems and objectives in the basin plan, and
constructing the necessary treatment facilities to
solve these problems, will prevent degradation of
Dillon Reservoir and the Blue River. Success in
this area is more likely if water quality manage-
ment strategies are supported by sound land use
programs in the county and municipalities, which
can lead to reductions in the amounts of "non-point"
pollutants entering the watershed.
The most important issue in this EIS is the imple-
mentation of the waste load allocations for Dillon
Reservoir.
Because of Dillon Reservoir's use as a municipal
water supply, the State of Colorado and the Denver
Board of Water Commissioners have additional juris-
diction over its quality. The State has adopted
the Public Health Service Drinking Water Standards,
which were published in 1962. The Denver Water
Board has adopted its own standards for the waters
in Dillon Reservoir, most of which are more stringent
than the State's (Denver Board of Water Commissioners,
1974). Recent Federal legislation (The Safe Drink-
ing Water Act, P.L. 93-523) calls for the states to
adopt new standards for safe drinking water. In-
terim Standards were published by EPA on March 14,
1975, and the states must adopt standards which
are at least as stringent as the published Interim
Standards. Note, however, that these drinking
water standards apply to finished water (after
treatment). Because of the generally good quality
of water in Dillon Reservoir, the Denver Water
Board is not expected to have problems complying
with the standards.
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SUMMARY OF PROPOSED PLAN
In developing the proposed water quality management
plan, six configurations of structural alternatives
were evaluated for treating municipal wastewaters
(sewage) generated in the basin. These alternatives
are shown in Figure 12 on page 74. Criteria used
in developing these alternatives are described in
the plan as follows:
1. Maintain or enhance water quality of
Dillon and Green Mountain Reservoirs.
2. Assure compliance with applicable stream
water and effluent quality standards.
3. Utilize existing facilities to the
greatest extent possible.
4. Maximize economics of advanced treatment
and sludge handling, treatment, and dis-
posal by regionalization.
5. No construction of raw sewage force mains
in the immediate vicinty of the reservoirs.
The alternative which the plan recommends for
implementation is alternative number six, which
calls for the following:
(a) Advanced wastewater treatment facility
at Swan Mountain Road to serve the en-
tire Upper Blue River Basin (2.0 MGD).
(b) Advanced wastewater treatment facility
at the confluence of Dillon Reservoir and
the Snake River to serve the Snake River
Basin upstream to approximately the con-
fluence of the North Fork and the mainstem of
the Snake River (1.0 MGD).
(c) Advanced wastewater treatment facility
at Arapahoe Basin (0.05 MGD).
(d) Advanced wastewater treatment facility
at Frisco to serve the Tenmile Creek
Basin upstream to Wheeler Junction (1.0
MGD).
(e) Advanced wastewater treatment facility
at Wheeler Junction (0.2 MGD).
(f) Advanced wastewater treatment facility
at the existing Silverthorne site to
serve all areas upstream to Dillon Reser-
voir (1.7 MGD).
(g) Advanced wastewater treatment facility
to serve the area between Green Mountain
Reservoir and the Silverthorne facility
(0.3 MGD).
(h) Secondary treatment facility to serve
the area adjacent to Green Mountain
Reservoir, discharging downstream from
the Reservoir (0.1 MGD).
(i) Secondary treatment facilities to serve
' the area tributary between Green Mountain
Reservoir and the Colorado River (0.05
MGD).
The proposed plan also discusses the alternative
of land treatment of municipal wastes.
The proposed plan recommends continuation of the
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current practice of disposing of sludge generated
by the wastewater treatment plants in a local
landfill, at least until such time as a regional
sludge disposal facility can be established in the
county.
The plan does not recommend a strategy for treat-
ment of non-point (i.e., urban or agricultural
runoff) sources of water pollution.
Based on.early 1974 construction costs, the plan
projects a total expenditure of $5,301,000 to con-
struct the facilities recommended in the plan which
do not now exist.
8
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10
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II
Description of the Environment
CLIMATE
The Blue River Basin ranges in elevation from over
7000 feet at the lower end of the basin to over
14,000 feet at the headwaters of the river. The
wide range of elevation, the shape of the basin,
and its location in the heart of the Rocky Moun-
tains, are the major controlling factors for the
climate of the area.
Generally speaking, Summit County's climate is
typical of high elevation mid-latitude continental
climates cold winters, mild summers, and wide
daily and seasonal variations in temperature. Most
precipitation in the county is in the form of snow,
which is generally dry and powdery. Summer pre-
cipitation is usually in the form of localized, in-
tense thunderstorms of relatively short duration.
Most of the water resources of the basin are
nourished by the snowpack which accumulates during
the winter. Annual precipitation in the basin ranges
from 12 to 14 inches, with the higher elevations
receiving the most moisture. Snowpack depths in
April at the higher elevations often exceed 60
inches, and the average annual basin snowfall is
about 160 inches. Total precipitation during an
average year is about 20 inches. Figure 3 depicts
average temperature and precipitation information
for the basin (at Dillon). Note, however, that the
data given for Dillon are not representative of
precipitation regimes throughout the county, pri-
marily because of the wide variations in topography.
Climate conditions have a significant effect on
streamflows in the basin. As the snowpack accumu-
lates during the winter when minimum temperatures
occur, streamflows are at a minimum. The flow at
this period is generally water from a prior season
of snowfall which has been stored in the aquifer
system. As air temperatures increase, the snowpack
begins to melt and streamflows increase. Melting
of the accumulated snow commences in mid-April and
continues through mid-July but surface runoff lags
almost a month behind snowmelt patterns. Stream-
flows start to increase in mid-May and reach their
peak flows after mid-June.
For additional discussions of the relationships
among climatic factors, water resources, and air
quality, see the sections of this chapter on Hydro-
logy" (page 17) and "Air Quality" (page 42).
SOILS
Soils types in the Blue River Basin include stable,
fertile flood-plain soils suitable for ranching, un-
consolidated glacial till, bare rock outcroppings,
and sterile tailings piles left abandoned from-gold
dredging days. Climatic conditions and other factors
have generally inhibited the development of stable
soils types in much of the basin. The lower reaches
of the basin (north of Dillon Reservoir) contain
extensive deposits of alluvial soils, covered with
native grasses and used primarily for ranching. In
some areas, these soils are developed to a maximum
depth of 50 to 60 feet. North of Dillon Reservoir,
large areas of these bottomland and soils have been
devastated by dredging operations.
11
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Average Monthly Precipitation &
Temperature at Dillon Figure 3
2.0 Precipitation X^ \
Temperature
12
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In the upper reaches of the streams and rivers,
glacial deposits with a maximum depth of approximate-
ly 9-12 meters (30-40 feet) are found. Both the
depth and quality of topsoil diminish with altitude
and the soils become coarser and less capable of
holding moisture. Above the tree line at approxi-
mately 11,500 feet there is essentially no soil,
only bare rock, gravel and pockets of sand.
The Soil Conservation Service (SCS) of the U.S.
Department of Agriculture has conducted soils map-
ping operations in the basin. General soils types
(associations) are shown on Figure 4. Descriptions
of the general characteristics of these soil as-
sociations are sumarized in Table 1. flote that
these data are quite generalized, and are primarily
intended for use as an overview of soils conditions
in the basin. A more detailed soil survey of the
county is now beina mrfinareH hy
As indicated in Table 1, the SCS data indicate that
all five of these general soil associations exhibit
"severe" limitations for use as septic tank leach
fields. Reasons for these conclusions are noted
at the bottom of the table. Note, however, that
septic tanks and leach fields are a fact of life
in the county, notwithstanding the analyses by SCS.
The availability pf more detailed soils data from
SCS may reveal limited areas of the county which
are more suited to septic tank usage; in the interim,
county officials rely on standardized soil perco-
lations tests and adherance to strict criteria for
the placement of such facilities. The "water quality"
section of this chapter will discuss septic tank
usage in the county in more detail.
GEOLOGY
The Blue River Basin is bounded by the Continental
Divide to the south and southeast, the Williams
Fork Mountains to the east, and the Gore and Ten-
mile Ranges to the west. The flat valley floor in
the northern part of the county is part of Middle
Park, an intermontane basin which extends up through
most of Grand County.
Bedrock in the basin ranges from pre-Cambrian,
highly contorted metasedimentary formations associated
with more gently folded sediments of Paleozoic and
Mesozoic age in the Tenmile Range (Bergendahl, 1963),
to sedimentary rocks and unconsolidated deposits
in the valley floors. Pre-Cambrian rocks in the
Upper Blue River Basin include gneisses, granitic
materials, and pegmatite (Singewald, 1951). These
are overlain by more recent sedimentary formations.
The area has been subjected to extensive deformation
during several periods of geologic time, with
resultant folding, thrusting, faulting, and general
contortion of the rock bodies. Many of these forma-
tions have been cut with igneous dikes and sills,
which are primarily responsible for the rich mineral
ore deposits which have been mined in the basin. Ore
deposits in the area include native gold, lead,
silver, copper, and zinc. Most mines are inactive
at present.
Unconsolidated deposits are widespread in the basin,
and occur on the valley'floors and on mountain slopes
as talus piles. Wisconsin-age glaciation was re-
sponsible for the formation of most of these de-
posits on the valley floors. Evidence of stream
terrace development during the glaciation is ap-
parent, especially in the lower (northern) part of
the basin. Deposits of unconsolidated materials
13
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General Soil Associations
U.S.D.A. Soil Conservation Service/1972 Figure4
Ptarmingan-Bobtail-Rock outcrop association: Very cold,
shallow and moderately deep, well drained, sloping to
steep soils and Rock outcrop on Alpine slopes.
Rock outcrop-Cryumbrepts-Cryaquepts association: Rock
ourcrop and rock slides and very cold, shallow, well
drained and poorly drained, sloping to steep soils on
Alpine slopes and Alpine meadows.
Cryoboralfs-Rock outcrop association: Cold, deep to
shallow, well drained, gently sloping to steep soils
and Rock outcrop and rock slides on high mountain
slopes.
Cryaquolls association: Cold, deep, somewhat poorly
and poorly drained, nearly level soils on flood plains.
Cryoborolls-Rock outcrop association: Cold, deep and
£rij& moderately deep, well drained, moderately steep and
£« steep soils and Rock outcrop on mountain slopes and
high benches.
14
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Clear Creek County
-------
TABLE 1
CHARACTERISTICS OF SUMMIT COUNTY SOIL ASSOCIATIONS
Soil Association
Number
33
-48
119
137
NOTES:
Component
Soils
Ptarmigan
Bobtail
Rock Outcrop
Minor Soils
Rock Outcrop
Cryumbrepts
Cryaquepts
Cryoboralfs
Rock Outcrop
Minor Soils
Cryaquolls
Minor Soils
Cryoborolls
Rock Outcrop
Minor
Extent, Slope,
Depth to Bedrock,
Inches*
35
20
25
?n
cu
45
35
20
65
Of)
t-\j
1C
1 y
70
in
ou
60
30
in
9-25+
9-25+
____
--»_.
9-25+
9-25+
9-25+
" ** *
0-3
3-25
____
_____
20-42
50-72
0
0
20
20-40
10-60+
60
20
0
I/ Limited depth .to bedrock
2J Slopes generally too steep
!/ Rock outcrops and/or shallow soils
4/ Seasonally high water table
5/ Flood hazard
Dashed lines indicate that data are too'variable to generalize
Source: USDA, Soil Conservation Service
Degree of Limitation,
Septic Tanks
severe
severe
severe
severe
severe
, 2/
severe 4/, 5/
I.
severe
severe
severe 4/, 5/
severe
severe
16
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which have been mapped in the upper basin Include
terrace gravels, moraine deposits, and alluvium.
The alluvium includes recent deposits, outwash
gravels from the glaciatlon, and sediments deposited
on the floor of a lake which existed in the vicinity
of Goose Pasture Tarn during the Wisconsin glaci-
atlon. Dredging of valley floor sediments for gold
in the late 1800's and the earlier part of this
century left extensive piles of these unconsolidated
deposits near the streambeds of the Upper Blue River
below Breckenridge and along some tributary streams
for short distances.
HYDROLOGY
A. General Information
The Blue River hydro!ogic basin 1s located on the
western slope of the Continental Divide. Drainage
from the basin is to the Colorado River, which flows
westward to Utah. Within the basin are an estimated
69 alpine lakes and about 290 km (180 miles) of
streams and rivers, many of which support fish,
other aquatic life, and waterfowl. Three reservoirs
have been constructed (Dillon, Green Mountain, and
Goose Pasture Tarn), and the two largest are ex-
tensively used to supply municipal and agricultural
water, and as recreation areas. Much of the water
in the basin has been appropriated for use outside
the county.
The headwaters of the Blue River originate at ele-
vations of approximately 4.27 km (14,000 feet).
The river flows 1n a generally northerly direction
through the county, and reaches its lowest elevation
of about 2.23 km (7320 feet) at its confluence with
the Colorado River near Kremmllng. The streambed
of the Blue River has a reach of approximately 95 km
(59 miles), and its gradient varies from approximate-
ly 53 m (175 feet) per mile in the upper parts of
the basin to about 3 m (10 feet) per mile near the
confluence with the Colorado River.
The Blue River is joined at Dillon Reservoir by the
Snake River and Tenmile Creek. The Blue River and
Its tributaries constitute a drainage basin of
158,510 hectares (61?. square miles) within Summit
County.
B. Streamf1ows
Streamflow is largely influenced by the snowfall
accumulation and melting pattern in the high mountain
watersheds. Nearly 70 percent of the average annual
runoff occurs during the months of May, June and
July. Runoff gradually recedes during the late
summer, and minimum flows are normally recorded
during the winter months. Relatively little runoff
is produced by the local thundershowers which occur
during the summer months 1n comparison to that pro-
duced by the spring snowmelt. Forty to fifty years
of streamflow data are available for the streams
tributary to Dillon reservoir. These data are
summarized on the following page in Table 2.
Agreements have been reached among the Denver Water
Board, the U.S. Bureau of Reclamation, and the
Colorado Division of Wildlife regarding minimum re-
leases from Dillon Reservoir to the Blue River.
Generally speaking, this amounts to a required re-
lease of at least 50 cubic feet per second (cfs) to
the Blue River or all the Inflow to the reservoir if
it 1s less than 50 cfs.
C. Reservoirs
Table 3 summarizes basic Information for the three
reservoirs located along the Blue River.
17
Goose Pasture Tarn, located south of Breckenridge
-------
Stream
Blue River
Tenmile Creek
Snake River
TABLE 2
STREAMFLOW DATA
Annual Average
Flow (cfs)
114.8
121.5
64.3
7-day, 10 year
Low Flow (cfs}
13.0
11.1
10.6
Source: Proposed Water Quality Management Plan
Reservoir
Goose Pasture
Tarn
Dillon
Green Mountain
TABLE 3
BASIC RESERVOIR DATA
BLUE RIVER BASIN
Surface Area
Hectares Acres
38.8
1336
728.7
96
3300
1800
Storage (A-F)
1,396
257,500
146,900
18
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along State Highway 9, 1s a private facility used
for recreation and as the water supply for Brecken-
ridge.
Dillon Reservoir was completed in 1964 to serve as
part of the domestic water supply system for the
Denver Water Board. Figure 5 shows Dillon Reservoir
and its general features. Note that the arms of
Dillon Reservoir are areas formerly drained by the
Blue River, Snake River, and Tenmile Creek. These
relatively shallow areas of the reservoir have
long detention times and limited mixing with the
main body, making them especially subject to water
quality problems, especially eutrophication. In
general, Dillon Reservoir is a deep, well-stratifled
reservoir, which means that vertical movement and
mixing of water is seasonally inhibited by the
temperature regime. The importance of this will
be discussed under "Water Quality" in this chapter.
Green Mountain Reservoir is located about 29 km
(18 miles) downstream (north) of Dillon Reservoir
(Figure 2). The reservoir was completed in 1943
as a feature of the Bureau of Reclamation's
Colorado - Big Thompson Project. Basically, the
reservoir operates as a downstream re-regulating
reservoir for this irrigation/municipal/industrial
water project which supplies water to the eastern
slope of the State. When sufficient water is
available, hydroelectric power is produced at
Green Mountain. The nominal generating capacity
of the facility is 21,600 kilowatts, and power
distribution is made through the Bureau of
Reclamation's distribution system to rural and
municipal users within Colorado. In general,
reservoir releases are operated on the basis of
electrical demand, and to satisfy downstream water
requirements and rights.
WATER USES
General water uses within the basin include: 1)
municipal needs within the basinj 2) maintenance
of the aesthetic and recreational values; 2) legally
allocated uses to serve east slope water users; and
4) legal obligations to satisfy downstream water
rights outside the basin. Major water allocations
are summarized in Table 4.
If all allocations from the upper basin were
utilized, water quantity problems may result. In
order to maintain minimum downstream flow and
satisfy all authorized depletions, approximately
234,000 acre-feet/year is required. The 10-year
annual drought flow is estimated to yield 148,000
acre-feet which is 86,000 acre-feet less than the
total allocations.
As Table 4 clearly indicates, the Denver Board of
Water Commissioners is by far the biggest user of
water in the Blue River Basin. The major features
of their water collection and distribution system
are shown in Figure 6. Appropriated water is de-
livered to the Denver area after diversion through
the Roberts Tunnel in the main body of Dillon
Reservoir (Figure 5). The Roberts Tunnel delivers
the raw water to the North Fork of the South Platte
River near Grant, Colorado, where it is eventually
removed for treatment and distribution. To date,
the Denver Water Board has not utilized its full
allocation from Dillon Reservoir. However, the
Water Board anticipates that water demands in the
Denver area will continue to increase as the metro-
politan area continues to expand. Additional water
diversion projects to Dillon Reservoir, such as
the East Gore Canal, Figure 6, are proposed for
construction in the future. This canal would
19
-------
Dillon Reservoir and Vicinity
Roberts Tunnel
South Platte
River Basin
North
Rese;
ilverthorne
E.P.A. Sampling Station
20
-------
General Nature of Diversion
City and County of Denver
* Storage Rights
Direct Rights
City of Colorado Springs
Colorado Big Thompson Project
Summit County
TOTAL
*excluding Direct Rights
Project
East Gore + Straight Creek
Eagle - Piney
Eagle - Colorado
Source: Denver Water Board
TABLE 4
WATER ALLOCATIONS
Acre-Feet/Year
179,000
Inflow to Dillon Reservoir
in excess of 50 cfs
9,600
52,000
17.000
257,600*
TABLE 5
PROPOSED FUTURE DIVERSIONS TO
DILLON RESERVOIR
Acre-Feet/Year
70,000
85,000
74,000
21
-------
Denver Water Board Projects
Figure 6
Green Mountain
Reservoir
State Bridge
Wolcott
Gypsum
Red Cliff
Pando
Breckenridge
Legend
Watershed Divide
Existing Reservoir
Proposed Reservoir
< Proposed Tunnel
< Proposed Conduit or Syphon
Proposed Pumping Station
o t n e n f
o ** I
22
-------
collect "excess" runoff from streams tributary to
the lower Blue River between Dillon Rservoir and
Cataract Creek on the eastern slope of the Gore
Range.
Water Board activities on the Western Slope of the
Continental Divide invariably generate controversy.
Proposals for the East Gore Canal, for example, may
be in conflict with the public's desire to establish
a larger Gore-Eagle's Nest Wilderness Area. In
addition, proposals for expanded water service in
the Denver area are looked upon by many as unnec-
essary, and by some as a further stimulus to pol-
lution-causing growth in the Denver metropolitan
area. Proposed future diversions to Dillon
Reservoir are shown in Table 5.'
With a combined surface area of 2,245 hectares
(5,545 acres) Green Mountain and Dillon Reservoirs
provide substantial enticement to those seeking
water based recreation. Both reservoirs are suit-
able for sail and motor boating, fishing, camping,
picnicking, snowmobiling and ice-fishing. In
addition, Green Mountain allows body contact use
(swimming and water skiing), which is prohibited
at Dillon. Figures 7 and 8 illustrate recreational
facilities available at these reservoirs. Streams
in the basin provide excellent cold-water fishing
opportunities.
There is no water-based commercial transportation
use, and limited agricultural use, existing levels
of which are steadily declining. The presence of
these waters adds aesthetic value of contiguous
developable lands which is reflected in land costs.
WATER QUALITY AND WASTEWATER TREATMENT
A. General
Simply stated, water which leaves the Blue River
Basin, either by diversion to Denver, or by flowing
downstream into the Colorado River, is not as pure
as it was when it originated in the Basin. At the
headwaters of the Basin, the water began as some of
the world's best from high quality mountain snow
packs and rainfalls. As it is collected in the
streams of the Basin and passes through those areas
influenced by man, the quality declines. Because
of the originally high quality, the relatively
small size and confined nature of the basin, and
the limited number of uses to which the water is
put, the degradation is not nearly as bad as in
say, the South Platte River as it flows through
Denver. However, the waters of Summit County
deserve no less attention just because they are
better in quality than most. In fact, the opposite
is probably true. Their use as a major water supply,
their recreational attributes, and the fate of the
Colorado River make it essential that exis_tinq
sources of pollution be abated, and that future
sources of pollution be prevented. All this, with
an economic, social, and environmental price tag
that is agreeable to a majority of people.
Because the stakes are high in improving water
quality, it is important that planning for water
quality management consider all factors which affect
water quality in a given basin. This section of the
EIS describes the existing water quality, and water
quality problems, in the Blue River Basin.
B. Stream Water Quality
Table 6 summarizes some important water quality in-
formation for the major streams in the Blue River
23
-------
Dillon Reservoir/us.
Outdoor Recreation
Figure?
Dillon Reservoir
ilverthorne
egend
b State Recreation Area
1 Boat Launch 4 Marina
2 Picnic Area 5 Overlook
3 Campground 6 Fishermen Parking
Source:U.S. Forest Service 1974
24
-------
Green Mountain Reservoir
gend
State Recreation Area
Boat Launch
1 Picnic Area
2 Campground
Figure 8
OL VA v2
3reen Mountain Reservoir
Heeney
3 Marina
4 Proposed Picnic Area
5 Proposed Campground
6 Overlook
>epartment Game FishA Parka,:W. J. Ul
25
-------
TABLE 6
WATER QUALITY DATA
MAJOR STREAMS OF THE BLUE RIVER BASIN
B
PARAMETER
BOD5
NH3-N
N02-N
N03-N
P04
Total P
mg/l-P
Molybdenum
Fecal Coll
/TOO ml
Total Dissolv
Solids
Blue River Blue River Blue River Blue River Tenmile Creek Tenmile Creek Snake River
above above below near at at at
reckenridge Dillon R. Dillon R. Kremmling Copper Mt. Dillon R. Dillon R.
(DWB) (WPCD) (WPCD) (WPCD) (DWB) (DWB) (DWB)
1.22 1.4 1.45
0.004 0.01 0.02
0.001 0.001 0.000
0.05 0.218 0.135 0.084 0.302 0.48 0.191
0.055 0.08 0.066
0.02 0.145 0.035 0.035 0.062 0.133 0.078
7.5 15.6 102.0 105.2 212.0 49.7 3.45
0.58 I/ 4.362/ 23.62_/ 31. 3 2/ 7.0 I/ 2.44 I/ 0.83V
e-« 95.1 90.4 109.0
26
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NOTES: All Data from EPA's STORE! System: DWB = Denver Water Board Stations
WPCD = Colorado Water Pollution Control Division Station
All Units are mg/1 except where otherwise noted.
V Measurement by MPN (most probable number) method
2/ Measurement by MFM (membrane filtration) method
Definitions:
BOD5 5-day biochemical oxygen demand
NH3-N = ammonia nitrogen
N02~N = nitrite nitrogen
NO -N = nitrate nitrogen
O
Fecal Coli = Fecal Coliform (bacteria)
27
-------
Basin. Note from the table that some pollution-
indicating parameters (examples: 8005, NH3-N) show
an increasing concentration as one travels down-
stream through the basin. Other water quality para-
meters either reflect an insignificant increase,
or even a decrease. Dissolved oxygen levels are
usually at or near saturation. To put some of
these numbers into perspective, compare them with re-
presentative figures from the main stem of the South
Platte River:
Parameter
BOD5
P04
NH3
Source:
South Platte River
Concentration
mg/1
15 - 75
U.S. EPA, 1974, Summary Report on the Long-
Term Water Quality of the South Platte
River Basin, 1966-1972.
With the exception of molybdenum concentrations
indicated in Table 6 (these are attributable to
the AMAX mining operation at the headwaters of
Tenmile Creek), stream waters in the Blue River
Basin are generally in compliance with water
quality standards. Pollutant concentrations shown
in Table 6 are primarily caused by municipal waste
discharges from sewage treatment plants and non-
point sources of water pollution such as runoff
from urban areas, septic tank leakage, and natural
sources. Actually, the "pollutant" concentrations
shown in the table reflect water quality conditions
which would be considered "background" in many other
parts of the country. As pointed out in Chapter 1,
however, the waters are susceptible to growths of
"undesirable aquatic life." Because they are
relatively fast-flowing, the stream waters of the
basin do not provide as much opportunity for algal
growth as does Dillon Reservoir.
Monitoring of the stream water quality in the Blue
River Basin is routinely done by the Denver Water
Board and the Colorado Water Pollution Control
Division (State Health Department). The latest water
quality data are available from EPA's computerized
STORET system. In addition, stream surveys of one
sort or another are occasionally conducted by EPA
and the Forest Service.
C. Reservoir Water Quality
No water quality-data are available for Goose
Pasture Tarn, the small, private reservoir located
north of Breckenridge, or for Green Mountain Re-
servoir. Since Dillon Reservoir is the largest
reservoir in the basin, and because it receives
the most direct inputs of wastewaters from a large
area of the county, this section of the EIS will
focus on it.
Right now, the overall water quality of Dillon
Reservoir can be quite simply described as "good".
Table 7 displays representative water quality data
taken during an EPA survey in the summer of 1973.
Refer to Figure 5 (page 20) to locate the sampling
stations indicated in the table.
With nitrogen and phosphorus levels such as those
shown in Table 7, Dillon Reservoir is described as
"oligotrophic" ~ meaning that the levels of nut-
rients necessary for plant (including algae) growth
28
-------
TABLE 7
DILLON RESERVOIR WATER QUALITY SURVEY
EPA - Summer, 1973
Location
Middle of Blue River Arm (A)
Surface
15' - 18' Deep
North end of Blue River Arm (B)
Surface
25' 35' Deep
East end of Frisco Bay (C)
Surface
10' Deep
East end of Giberson Bay (D)
Surface
20' - 25' Deep
West end of Snake River Arm (E)
Surface
30' - 35' Deep
West end of Dillon Bay (F)
Surface
15' - 24' Deep
Center of Main Body (G)
Surface
30' - 35' Deep
Temperature
°C
15.3
7.5
14.6
6.5
15.6
9.2
16.1
8.0
15.2
6.0
15.3
6.0
14.9
5.5
Dissolved
Oxygen
mg/1
8.4
7.7
7.7
7.6
7.6
7.3
8.1
8.1
7.9
7.5
7.8
7.4
7.9
7.6
Total
Phosphorus
mg/1
0.013
0.013
0.014
0.013
0.020
0.020
0.011
0.011
0.010
0.008
0.012
0.010
0.038
0.009
Total
Nitrogen
mg/1
0.26
0.29
0.32
0.32
0.22
0.30
0.26
0.29
0.22
0.22
0.29
0.23
0.12
0.25
29
-------
are low. With increased loadings of nutrients to
the system* it is probable that the reservoir will
eventually become "eutrophic", which has been de-
fined by the Colorado Water Pollution Control Com-
mission as:
The process of a lake becomina rich
in dissolved nutrients thereby en-
hancing the growth of aquatic plants
leading to possible seasonal oxygen
deficiencies and accelerating the rate
of lake aging. (Source: Proposed Water
Quality Management Plan)
Studies which have been carried out by EPA as part
of the process of formulating the Water Quality
Management Plan have shown that Dillon Reservoir is,
by its nature, susceptible to this process of
cultural eutrophication. Further, the studies have
demonstrated that phosphorus is the critical nut-
rient in the system, and that greater amounts of
phosphorus introduced into Dillon Reservoir via
waste discharges and natural sources may even now
produce those growths of "undesirable aquatic life"
which could ultimate!v int.prfprp with t>* current
beneficial uses of the water. For a good summary
of the studies and data which have led to these
conclusions, the reader is referred to the "Waste
Load Allocation Plan, Blue River Hydrologic Basin",
which was prepared for the Colorado Department of
Health by R. Keith Hook and Associates of Colorado
Springs. Because this Waste Load Allocation Plan
has to some extent formed the basis for the water
quality management plan which is under consideration
in this EIS, the critical portions of it are re-
produced as Appendix "B". An additional study
which is useful is the "Dillon Reservoir - Blue
River Study Colorado," published by the Region VIII
office of EPA in January, 1974 (EPA number
S & A TIB - 28). By reference, the descriptive
sections of both these studies are included as
part of this EIS.
To concisely sum up the water quality situation in
Dillon Reservoir:
--The water quality is now generally
good.
--The reservoir can be characterized as
oligotrophic.
Organics, nutrients, and other water
pollutants are being introduced into
the reservoir system from sewage treat-
ment plants (point sources), and natural
and urban runoff (non-point sources).
Because of the physical characteristics
of the reservoir, these pollutants could
lead to "indesirable aquatic growth"
(algae blooms), and other conditions
indicative of eutrophication. Phosphorus
is especially important, and its inputs
to the system must be limited.
D. Wastewater Treatment
Domestic wastewaters generated in the basin are
generally treated by septic tank/leach fields,
small treatment plants designed to serve only a
limited area (e.g., a subdivision), or publicly
owned treatment plants serving an entire town or
series of developments. Appendix "C" summarizes the
procedures to be followed in applying for an individ-
ual sewage disposal permit. Figure 9 indicates the
locations, sizes, and general types of domestic
wastewater treatment plants around the basin. Refer
to the enclosed EPA booklet, "A Citizen's Guide to
Clean Water" for a description of "secondary" and
30
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"tertiary" (advance waste treatment).
Generally speaking, the small treatment facilities
serving individual subdivisions or other small areas
are "package plants". These plants usually provide
secondary treatment, and are poorly operated and
maintained. Effluents from these plants generally
cannot meet the water quality standards.
The larger treatment plants in the basin, especially
the ones discharging directly to Dillon Reservoir,
are better operated, and generally produce higher-
quality effluent, although there are some problems.
Some facts and figures about the major facilities:
1. Breckenridae Treatment Plant: Located on the
Blue River just north of Dillon reservoir. Advanced
treatment with filtration and chlorination of ef-
fluent. Canacitv of 2 MGD (million gallons per
day). Constructed with Federal assistance. High
chlorine content of effluent is endangering the
fishery resource.
2. Frisrn Plant- Located on Dillon Reservoir's
Tenmile Creek Arm. Secondary type (extended
aeration), with "polishing pond". Effluent cannot
consistently meet standards, even for biochemical
oxygen demand (BOD). No phosphorus removal cap-
abilities. Constructed with a capacity of 1 MGD,
local money used. Plans are now underway to expand
and upgrade this plant.
3. Silvprtihorne Treatment Plant! Capacity slightly
less than 1 MGD. Infiltration problems sometimes
result in flows which are much more than the plant
capacity. Funding from a variety of sources, in-
cluding Federal. Additional planning for upgrading
is now underway. Disharges into the Blue River be-
low Dillon Dam.
31
4. East Dillon (Summit Cove Plant): Advanced
treatment design capcity of 500,000 GPD. Plagued
by infiltration problems. The county hopes to inter-
cept flows into this plant and treat everything in
the area at their Phase "D" Plant after it is ex-
panded. Plate 1 shows the exterior of the Summit
Cove Plant.
5. Summit County Phase "D" Plant;located right
next to the Summit Cove Plant. Capacity of 250,000
GPD is already being exceeded, according to the
County. High infiltration is certainly part of the
problem. The County is now planning to expand the
plant. This advanced treatment facility produces
a generally high-quality effluent. See photo of
this plant, Plate 2.
With the exception of the Summit Cove Plant, the
facilities listed above are integral parts of the
proposed Water Quality Management Plan. Other
treatment plants shown in Figure 9 are not major
dischargers, and have not, therefore, been discussed
above.
Table 8 shows some representative effluent data
from some of these treatment plants.
As mentioned in the previous section (Reservoir
Water Quality), studies have identified phosphorus
and its cpmpounds as the "limiting" nutrient for
nuisance algal growth in Dillon Reservoir. This
simply means that if significant quantities of
phosphorus are added to the system, algae and other
plant life will proliferate. All the other in-
gredients are already present for this plant growth
in the reservoirs. The likelihood that this might
happen is the reason that this segment of the Blue
River was classified as "water quality limited" by
the Colorado Department of Health (see Chapter 1).
-------
Wastewater Treatment
Facilities Locations/1975 FigureQ
Key Facility Capacity (MGD)
1 Arapaho Basin -
*2 Summit County (Phase D) .25
3 E. Di I Ion Water & Sanitation Dist. .05
4 Dillon-Silverthorne Joint Admin. .5
5 Brecken ridge 2.0
6 Frisco 1.0
7 Copper Mountain .6
8 Blue River Condos .02
9 Shangri-La .02
Me Oil I Placer .01-.02
Advanced Water Treatment
Secondary Water Treatment
Source: Summit County Health Department -1975
32
-------
-------
...
;, ftrtfv.
PLATE 1: The "Summit Cove" Plant, owned by the
East Dillon Water and Sanitation Dis-
trict, operated by Summit County.
34
-------
PLATE 2: Interior view of the Summit County
"Phase d" plant, located next to the
Summit Cove plant on the Snake River
Arm of Dillon Reservoir.
35
-------
TABLE 8
REPRESENTATIVE EFFLUENT DATA
WASTEWATER TREATMENT PLANTS, SUMMIT COUNTY
Parameter
BOD
(mg/1)
Phosphorus (mg/1)
(pounds per day)
NOTES: I/
II
Frisco
13-34
1.9-8.
avg.
I/
0
29.2
Breckenridoe
12-53
I/
4.1-6.0
24-46
East Dillon
2-3
.035-. 09
0.004-0.08
I!
I/
Data from Denver Water Board Grab Samples, 10/74 - 3/75
Data from "Dillon Reservoir - Blue River Study", EPA, 1974
3_/ Phosphorus reported as PO,-P
4/ Phosphorus reported as total P
TABLE 9
DOMESTIC WASTE LOAD ALLOCATION OF PHOSPHORUS TO DILLON RESERVOIR
Location
Blue River Arm
Snake River Arm
Tenmile Creek Arm
Main Body
Concentration, mg/1
0.013
0.010
0.015
0.013
Tributary Arms are Critical Areas
Source: Waste Load Allocation Plan, 1974
Average Allowable
Loading, pounds/day
1977 1992
1.88
0.67
1.00
14.6
2.18
0.70
1.05
15.0
36
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For all water quality limited segments, a "Waste
Load Allocation Plan" must be prepared (see
Appendix "B", where the critical portions of the
Plan for the Blue River are reproduced). For the
Blue River, identification of the problem led to
the classification of "water quality limited",
which led to the preparation of the Waste Load
Allocation Plan. This plan was approved by EPA in
May of 1974. Allocations of phosphorus loadings
to various portions of Dillon Reservoir from the
major municipal waste dischargers in the basin are
shown in Tables 9 and 10.
The phosphorus limitations imposed on the reservoir
arms and ultimately to the Muncipal Waste dischargers
by the Waste Load Allocation Plan are designed to
protect water quality, and are consistent with the
statutory responsibilities of EPA and the Colorado
Department of Health. The allocations were based
on the best data available at the time. As such,
they should be a useful tool, in conjunction with
the proposed Water Quality Management Plan and
other criteria, for planning in the County. Jl
more detailed studies of the basin are made in the
future which show a need tn revise the nhncphnru*;
Allocations either upwards nr downwards, surh'
ad.iustmpnt.s can HP
Putting these phosphorus allocations to work in
the basin without creating undue economic hardships
on the county or local governments, has not been
the world's easiest task. There are two ways of
going about it one via the permit program
established by the National Pollutant Discharges
Elimination System (NPDES), and another via the
water quality management planning process, which
of course is the subject of this EIS.
NPDES permits have been issued to all the major
municipal waste dischargers in the basin. During
the process of issuing these permits, questions
were raised concerning the reasonableness of some
of the phosphorus allocations. Especially import-
ant was the issue of seasonal flow variations in
the plant discharges, which occur because of the
variable populations in the basin during and in
between ski season. As a result, the phosphorus
limitations included in the NPDES permits reflect
technological constraints of attaining low phos-
phorus concentrations at high flows, rather than
the more restrictive effluent concentration limits
shown in Table 10. Poundage limitations of the
waste load allocations, however, have not been
modified. As the permits expire and are reconsidered
by the Colorado Department of Health, the permit
restrictions will be revised as necessary. EPA's
rationale for modifying the provisions of the Waste
Load Allocation Plan is presented in Appendix "D".
Excerpts from the major permits which have been
issued to dischargers into tributaries of Dillon
Reservoir are summarized as Appendix "E".
Some of the dischargers in the basin are operating
their treatment plants under some type of "compliance
schedule" for bringing their treatment plants in
line with the provisions of the Waste Load Allocation
Plan or their NPDES Permit. These schedules are
based on environmental (water quality) and economic
factors, and require the dischargers to upgrade
treatment facilities within a reasonable time.
Recently, a new problem has surfaced regarding the
waste load allocations which have been made for
the Snake River arm of Dillon Reservoir. While the
Waste Load Allocation Plan provided for allocating
waste loads to the reservoir arms and the municipal
dischargers on each arm, it did not address the
ultimate problem as the plan's goal of con-
37
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TABLE 10
DOMESTIC WASTE LOAD ALLOCATION OF PHOSPHORUS TO DISCHARGERS TRIBUTARY TO
DILLON RESERVOIR AND RESULTANT RESERVOIR CONCENTRATIONS - 1977
Location
Upper Blue River Basin
*(a) Breckenridge San.
District
(b) Blue River San. Dist.
(New Eldorado)
(c) Quandary Lodge
(d) Valley of the Blue
(e) McDill Placer
Snake River Basin
*(a) Summit Co. Phase 'D'
*(b) East Dillon Water and
San. District
(c) Key West Farms
(d) Keystone
*(e) Araphahoe Basin
Tenmile Creek Basin
*(a) Frisco San. District
*(b) Copper Mountain Water
and San. District
Average P
Discharge, Ibs/day
1977
1.82
0.023
0.018
0.009
0.009
0.588
0.029
0.012
0.029
0.012
0.77
0.23
Maximum Effluent
Concentration, mg/1
0.188
0.188
0.188
0.188
0.188
0.134
0.134
0.134
0.134
0.134
0.171
0.171
Resultant
Concentration, mg/1
in Reservoir
0.013
0.010
0.015
Source: Waste Load Allocation Plan, 1974
* = Major dischargers to Dillon Reservoir
38
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soli dating treatment facilities becomes a reality,
who determines the sharing and distribution of the
treatment plant's waste load allocation among the
several sanitation districts? For an example of
how the waste load allocation system works, see
Appendix "F".
One purpose of the original allocation plan V/as to
encourage the consolidation of the East Dillon
Water and Sanitation District's Summit Cove Plant
with the Summit County Phase "D" plant. The
existing waste load allocation for the Summit Cove
Plant could then be added to the allocation for
the Summit County plant. With Summit County in
charge of operating the plant, then, the question
becomes one of further allocating or sharing the
entire waste load allocation for the Phase "D"
plant. Who should decide how the allocation is
to be shared Summit County? The State of
Colorado? EPA? The answer to this question is
critical, primarily because commitments to hook up
to the system have already been made in some cases.
Providing a "fair share" of the allocation to the
East Dillon Water and Sanitation District will thus
have a direct impact on land use in the county. The
problem is further complicated by legal and
financial constraints facing the sanitation district,
If they find themselves in a position of not being
able to afford hooking up the Phase "D" plant in
the near future, time will run out on their
compliance schedule for the NPDES permit and the
waste load allocation, necessitating either im-
provements to their facility, or enforcement action
by the state. EPA and the State of Colorado are
currently evaluating these complicated issues.
Ultimately, legal action may be required to resolve
the questions.
unique situation at the Breckenridge plant. This
plant, as shown in Figure 9, is located on the Blue
River just upstream (about 100 yards) from Dillon
Reservoir. This short stretch of the Blue River
has been determined by the Colorado Division of
Wildlife to be the only spawning area in the basin
available for Brown Trout. The Division of Wild-
life uses this portion of the river as a supply
area for Brown Trout eggs to be stocked throughout
the State, and they consider this area to be an ir-
replaceable fisheries resource.
Chlorine is used for disinfection of the effluent
at the Breckenridge Plant. The Denver Water Board
is especially concerned that all sewage effluents
which enter Dillon Reservoir be properly disinfected.
However, chlorine, in sufficient concentrations, is
also toxic to fish. 'The Division of Wildlife is
quite concerned that chlorine doses applied to the
plant effluent during times of low-flow could be
sufficient to cause a massive fish kill. This is
most critical during the spawning period for the
Brown Trout, approximately October 1 to November 1.
The Division of Wildlife is also concerned that a
plant malfunction at Breckenridge could cause a fish
kill.
Because of the identified problem of chlorine
toxicity at Breckenridge, that plant is on a com-
pliance schedule for removing excess chlorine from
the effluent. This could be accomplished either
by adding 'special dechlorination equipment, or by
switching to an alternate means of disinfection,
such as ozonation. At the present time, sufficient
funds are not available from the State of Colorado
to allow these goals to be accomplished.
Special mention should be made here of a rather
39
Sludge generated at treatment plants in the county
is disposed of in the county land fill (Plate 3).
-------
PLATE 3: Disposal site for sludge produced
at wastewater treatment plants in
Summit County.
40
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E. Non-Point Pollution and Future Planning
The above discussion has considered only water
quality problems caused by point sources of pol-
lution. In any area occupied or influenced by
humans, water pollution problems are complicated
by runoff from agricultural lands and urbanized
areas. These waters will carry materials such as
silt, nutrients, salts, organics, oils and greases
into area receiving waters. More often than not
treatment for these waters is not available,
primarily because of the expense of collecting the
wastes, and the fact that the runoff itself is not
continuous, as is more or less the case with domes-
tic sewage. Although no data are available in
Summit County,it is certain that non-point sources
of pollution are a problem. Past practices of
poor road design in subdivisions, runoff from
urbanized areas, and effluents from septic tank
leach fields are probably the major contributors.
It is likely that these pollutants, especially the
nutrients, are continually adding to the eutro-
phication potential of Dillon Reservoir.
County and local control of land-use practices
through careful planning and good zoning can re-
duce the impact from non-point sources of water
pollution. Especially important are county
practices of subdivision approval, and septic tanks
(see Appendix "C").
Non-point pollution problems in the county will be
analysed in detail during the next two years, as
the "Areawide Waste Treatment Management Program"
created by Section 208 of the Federal Water Pollution
Control Act Ammendments of 1972, gets underway.
This program, financed entirely by Federal funds
and administered by EPA, will, in addition to
identifying sources of non-point pollution and
devising control strategies, accomplish the
following:
1. Identify treatment works which will be
required over the next 20 years, establish
priorities for their construction, and
develop the necessary institutional and
financial frameworks to assure their
construction;
2. Identify and devise control strategies
for pollution problems from mining
operations;
3. Identify and devise control strategies
for pollution problems from construction
activities;
4. Identify and devise control strategies
for other waste disposal practices which
could affect water quality.
Control strategies may include land-use controls,
as well as more conventional water pollution controls.
The "208 Plans" are envisioned more as true
environmental plans than traditional water quality
management plans. For Summit County, the 208 Agency
which will develop the plan is the Northwest Colorado
Council of Governments (NWCOG). Their 208 Plan will
include Summit, Grand, Eagle, Pitkin, Jackson, and
Routt Counties essentially six separate drainage
basins. A final "work plan" for this program is
now available from NWCOG, EPA, or the State of
Colorado. NWCOG is slated to receive $530,000 for
this work.
41
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AIR QUALITY
Even though Summit County is viewed by many who
patronize its ski resorts and other attractions as
a rather pristine mountain paradise, air pollution
problems similar to those found in heavily urban-
ized areas can and do occur. At the present time,
most air pollution problems in the county are
attributed to particulate emissions from fireplaces,
and automotive emissions. No major sources of
industrial air pollution exist in the county.
To date, no detailed assessment of the air quality
situation in Summit County is available. However,
with assistance from EPA and the Summit Citizen's
Association, Summit County has contracted with
Ambient Analysis, Inc., to perform such a study.
The following description of the air pollution pro-
blems in Summit County is excerpted from a proposal
submitted to Summit County by Ambient Analysis:
Summit County occupies a long north-
south valley, which is open on the
north end. The valley floor ranges
generally above 8000 ft MSL, while
the valley walls consist of mountain
ranges in which the few passes are
generally above 11,000 ft. and the
mean height probably exceeds 12,000
ft. The valley is quite narrow just
upstream of the point where Boulder
Creek flows into Blue River. A valley
of this type (particularly the upper
portion) is frequently cut off from
the general air movement and, when
it is, the air in the valley either
becomes stagnant or it develops an
internal circulation. In either
case pollutants released into the
42
air in the valley will be retained
there.
The short-lived constituents in the
pollutants will soon be converted to
other constituents or deposited on
the valley floor and walls. The
long-lived constituents will continue
to accumulate in the atmosphere. Either
may become a hazard. For example,
particles which are large (e.g. fly ash
from a power plant) will settle out
rapidly, but in the area where they
fall, they constitute an undesirable
problem, to say the least; on the
other hand, the small particles which
settle slowly may accumulate in the
air in large enough quantities to severely
reduce visibility. They also constitute
a respiratory hazard.
In recent years Summit County has become
a tourist mecca. The Interstate 70-U.S.
6 system crosses the valley roughly in
the middle. This highway is heavily
travelled. Development of oil shale and
coal reserves in Western Colorado will
contribute to increased usage. Continued
development of both summer and winter
recreational areas will also expand the
use of U.S. 6. Finally, with the Eisen-
hower Tunnel making travel through the
Rockies faster, more people who are simply
travelling east or west will choose to
travel through Summit County.
Colorado 9, which extends the length of
the county, has also become a heavily
travelled highway; it and Colorado 91
-------
provide well-used access to all major arms of
the valley.
These highway systems, by bringing streams
of fuel-burning autos through the valley,
serve as a diffuse, but highly important
pollutant source. In particular, the
area between Copper Mountain and the
west entrance of the Eisenhower Tunnel
can expect to receive copious pollutant
continuous. There will be peaks
and valleys in the amount. It will vary
from hour to hour, from day to day and
from season to season, but it will never
cease to be dumped into the atmosphere,
and much of it will be taken up by the
local flora and fauna.
There is a rapidly increasing semi-
permanent population in Summit County.
That population is among the most af-
fluent in the world. It associates
fireplaces with mountain living, and
it uses those fireplaces most when the
atmosphere is cold and stagnant and so
can least tolerate the effluent from
inefficient burning. That population
also demands restaurants which use
grills to prepare much of the food they
serve. All of these things serve as
pol1utant sources: taken together they
are a large diffuse source. That such
diffuse sources can create pollution
problems has been demonstated already
in at least two valleys in Western
Colorado. Unlike power plants or
other point sources, the total effluent
from residential areas and highways
cannot be readily determined quantitatively.
This study, now being conducted by Ambient Analysis,
is expected to be available by May of 1976. Interim
results of their work indicate that concentrations
of carbon monoxide and particulates (including
asbestos fibers) are rather high, especially near
1-70. Some additional information on air quality is
available from: Hoi ben, Brent N., and W.E. Marlatt,
1974, Air Pollution Potential Analysis of Summit
CountyT submitted to the Summit County Planner's
Office, September , 1974. The summary of that
report is quoted below.
This study showed that in general air
pollution is currently well below the
federal and state standards. The
standards are exceeded only under very
severe air stagnation situations. An
increase in the urbanization and there-
fore emission sources could cause serious
problems in the future particularly in
the Breckenridge and Straight Creek areas.
The worst pollutants in terms of approaching
existing standards are particulates resulting
from fireplaces. Hydrocarbons from vehicular
traffic follow.
A meteorological and air quality data
inventory for Summit County was conducted
and presented in this report. Basically
this data was inadequate for computer
model analysis. Therefore a meteorological
monitoring system is recommended for the
county with secondary emphasis on monitoring
background air quality. Recommendations are
made concerning limitation of present and
future emission sources.
43
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Despite the limited data concerning air quality
in Summit County, it can be safely stated that
automotive emissions and fireplace emissions account
for the majority of air pollutants in the county
airshed. If the county continues to grow, and
as more ski traffic and summer visitors utilize
1-70 and Colorado Highway 9, air pollution problems
can be expected to increase. Air quality is one
of the major factors which must be considered by
the County in developing land use plans based on
the'environmental "carrying capacity" of the county.
BIOLOGICAL RESOURCES
The Blue River Basin is a narrow valley surrounded
on three sides by high mountains. Elevations range
from 7,320 feet (at the confluence of the Blue and
Colorado Rivers) to over 14,000 feet. The most
important plant communities in the river basin are
the montane forests, subalpine forest and alpine
tundra. Montane forests cover the lower mountain
slopes and are interspersed with open grass
meadows. In the valley in the northern section of
the basin, grass and sagebrush extensions occur.
Along the streambed some irrigated hay meadows
are in operation. At higher elevations the montane
forests give way to subalpine forests, and above
the timber!ine alpine tundra occurs.
The montane forests are composed of mixed or pure
stands of Ponderosa Pine, Douglas Fir, Lodgepole
Pine and Quaking Aspen. Willows, cottonwoods and
aspen may be found along streambeds, together with
other herbaceous plants, sedges, grasses and rushes
Shrubs commonly found in the montane zone include
Antelope Bitterbush, Chokeberry, Wild Current and
Sagebrush. The common herbaceous plants include
Cinquefoil, Geranium, Asters, Columbine, Pasque
Flower, Lupine, Paint Brush, Fairly Slipper, Golden
Banner and Monkshood. In the open meadows, grasses
and sedges are rommon, with occasional wildflowers
and shrubs.
Important components include Thurber Fesque, Idaho
Fesque, Nodding Brome, Oakgrass, Timothy, and
several species of wheat grasses and blue grasses.
At higher altitudes the dominant trees of the sub-
alpine forests are Englemann Spruce and Subalpine
Fir. These species generally form dense stands and
the understory is sparse. Plants commbnly found
include Huckleberry Arnice, and the various grasses
and sedges.
Above the timberline, generally at altitudes of
3.5 km (11,500 feet) and over, alpine tundra occurs,
Bare exposed rock in this region may be covered by
lichens. In the meadows the vegetation consists
of sedges, grasses, clover, various small forbs
such as Alpine Phlox, Alpine Forget-me-not, Blue-
bells, Gentian, Fairy Primrose as well as stunted
woody plants such as willows and Bog Birch.
Elk and Mule Deer are the most common of the large
mammals found in the region. Black Bear, Mountain
Lion and Bighorn Sheep may also be found in the
area, but are uncommon. Several smaller carniver-
ous mammals including Bobcat, Coyote, Red Fox,
Weasel, Marten, Mink, Badger, Striped Skunk and
Racoon may be found. Common rodents include
Beaver, Porcupine, Red Squirrel, Golden-mantled
Pocket Gopher, Bushy-tailed Woodrat, Marmot and
a variety of mice and voles. The Pika, White-
tailed Jackrabbit, Mountain Cottontail and Snow-
shoe Hare are also present; and several species
of shrews and bats are found.
44
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Bird life is abundant in the area and includes year-
round residents and migratory species. Some of the
common forms are the Raven, Clark's Nutcracker,
Canada Jay, Steller's Jay, Magpie, Dipper, Blue
Grouse, Pigmy Nuthatch, Audubon's Warbler, Hermit
Thrush, White-Tailed Ptarmigan, Brown-Capped Rosy
Finch, Yellow Bellied Sapsucker, Red-shafted Flicker
and several species of ducks, hummingbirds and
hawks.
Common reptiles and amphibians include the Western
Garter Snake, Leopard Frog, Cricket-Frog, Western
Toad and Tiger Salamander. No poisonous reptiles
are found in the area.
The fish population in the streams include trout,
sculpin and minnows and fishing is a major re-
creational activity in the area. The Cutthroat
Trout is native to Colorado but Rainbow, Brook and
Brown Trout have been introduced into Colorado's
stream's and all but the Rainbow trout breed there.
A natural Brown trout spawning migration occurs
from Dillon Reservoir up the main stem of the Blue
River.
The distribution of wildlife in the area follows
no clear cut patterns although certain animals and
birds (e.g. Pika, White-tailed Ptarmigan and Brown-
Capped Rosy Finch in the tundra region) may be
characteristic of a particular vegetative and
climatic zone. The ranges of the larger mammals
and predators have been modified to a large extent
by the various activities of man. The natural
winter ranges of elk, deer and possibly sheep are
being usurped and destroyed by man's activities
and these herbivores are forced to winter at high-
er altitudes. The winter range of mule deer is
on the lower mountain slopes and bottomlands,
45
characterized by pinyon-juniper woodlands and
sagebrush, and that of elk is at higher elevations
in the conifer-aspen forests. With expanding re-
creational use of this area and with the use of
snowmobiles, even more encroachment on the natural
habitat of the larger animals will occur. Other
animals that once may have ranged in the area but
are now gone include the wolverine, lynx, wolf,
and grizzly bear. Predators in particular have
been historically hunted down.
Several animals found in the Upper Colorado Region
are on the endangered species list or are in the
treatened status. However, only a few of these
species are likely to be found in Summit County.
The American peregrine falcon, Falco peregrinus
is considered an endangered species. This bird
no longer breeds in the eastern United States and
is generally decreasing in the west. In the upper
Colorado Region the peregrine falcon is uncommon
but should be in less immediate danger there than
in many other parts of the country as contamination
by pesticides, a major factor in the.decline of
the species, is at a relatively low level.
Two endangered fish are the Humback Chub, Cila
cypha. and the Colorado River Squawfish, Prvcho-
chailus luclu$. which are native to the Colorado
River drainage system. Both are adapted to a
swift water environment. Their natural habitat
has been partially obliterated by reservoir con-
struction and their reproductive requirements af-
fected by lowered temperatures in the tailwater
areas. Both species are quite rare in the natural
stream segments remaining.
Not officially included but a candidate for the
-------
endangered species list is the Colorado River Cut-
throat, Sal mo dark! pleuriticus. This native of
the headwater streams of the Colorado River exists
as a pure or relatively pure form in few remaining
areas. Isolated Colorado River Cutthroat popu-
lations have been found in remote tributary reaches
within Colorado, Utah, and Wyoming. In some
localities these populations are threatened by
habitat deterioration resulting from watershed
erosion. Generally, though, hybridization with
Rainbow trout and other types of Cutthroat trout
is eliminating the sub-species.
POPULATION
It would be naive to claim that accurate pro-
jections of population are easy to make. In a
recreation-oriented area such as Summit County,
the job becomes even more difficult. Factors
such as the availability of new recreational areas,
skier capacity of existing areas, zoning, and the
economy are often impossible to predict, yet they
are extremely important in making population
projections. Especially important in a recreation
area is the distinction between full-time (year-
round) residents and the transient population that
utilizes the recreation facilities. The transient
population may include day visitors, or those who
require lodging for one night, a weekend, or even
longer.
For planning purposes, the ideal condition is re-
presented by the use of one population projection
that is agreeable to all concerned planning agencies.
In planning for wastewater treatment facilities,
this is especially important, since the availability
of these facilities must be in concert with the
availability of other utility services. This
situation is further complicated by considering the
mechanical limitations of some wastewater treatment
plants, since (in some cases) an underutilized
sewage treatment plant cannot be operated efficiently
enough to produce a high-quality effluent. Naturally,
an overloaded facility cannot be expected to do its
job. In summit County, then, the combination of
high seasonal recreation use (and resulting highly
variable sewage flows) and the large range of
population projections has made planning for
wastewater treatment facilities most difficult. The
proposed Water Quality Management Plan utilized the
best available population data to determine both
the level of treatment required to meet the re-
quirements of the waste load allocations, and the
sizing of facilities required.
Historical data from the U.S. Census Bureau clearly
indicate how full-time residents of the county have
increased in numbers:
Year
1950
1960
1970
Population
1,754
2,073
2,655
These data show an 18% increase from 1950 to 1960,
and a 28.6% increase from 1960 to 1970. A State
Division of Planning population count in Summit
County in 1972 showed a 40% increase in full-time
residents since 1970. Table 11 compiles available
data concerning population projections for full-time
residents of the county.
Population and land use studies for both full-time
and seasonal residents have been completed by
46
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TABLE 11
PROJECTED FULL TIME RESIDENTS OF SUMMIT COUNTY
Consultant I960 1970 1980 1990 2000
U.S. Bureau of the Census 2,073 2,655
Planning Dynamics Corp.
(Therese Lucas) 22,500 34,240 55,800
Obllnger-Smlth Corp. 17,000 40,000
Colorado State Division of
Planning 3,000 4,000
Carl S. Becker Company 11,711
Charles Gathers & Assoc. 3,800
McCall-Ellingson 44,000
(1977)
47
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various consultants for different agencies. It
has been found that many differ markedly. Results
of a few studies for full-time residents are tabu-
lated in Table 11. The population given reflects
full-time residents of Summit County only. It is
difficult to project a population for that portion
of the Blue River Basin outside of Summit County
but a resident population of 50 at present and
200 in 1980 may be a realistic estimate.
Qf the studies listed in Table 11, the statewide
study by Planning Dynamics Corporation under the
direction of Therese Lucas, has been considered
to be the most sophisticated approach and has been
used in developing the proposed Water Quality
Management Plan. The population projections
generated by that study are trend projections based
on an evaluation of the expected strength of the
economy and the prospect of employment opportunities
in each of the geographic areas of the state. In-
cluded in the projections are dwelling units, re-
sidential acreage, water demand, sewerage demand,
and school enrollment as well as population and
employment projections. In counties where rec-
reation is the major industry.,.recreational
housing is included in the projection of dwelling
units. This will account in part for the seasonal
short-term population experienced in recreational
areas such as the Blue River Basin. The impact
of this maximum or peak population expected during
the planning design period is of more real impor-
tance to the management of water quality than the
impact of the full time residential level of popu-
lation. Listed in Table 12 are the dwelling units
projected by Therese Lucas study. A seasonal
resident population is then projected using an
average population density of 3.5 persons per
dwelling unit. This does not account for all popu-
lation added by visits of one day or less.
In the Water Quality Management Analysis prepared
by the Environmental Protection Agency and the
Colorado State Department of Health, peak seasonal
populations were derived for the various sub-basins
in the study area which reflect both seasonal re-
sidents and population added by day visits. These
projections are shown in Table 13.
Population projections for the Green Mountain
Reservoir Area and that portion of the Basin in
Grand County are projected from the Interim Water
Quality Management Plan inventory of land develop-
ment and rates of increase projected by the Therese
Lucas study. These are:
Green Mountain
Reservoir
Blue River in
Grand County
1977-1980
670
200
1990-1992
1,100
300
While peak population has the maximum effect on
wastewater treatment plan efficiency of operation,
a yearly cycle of wastewater loading is important
to the analysis of reservoir water quality response.
Assuming that the yearly variation in wastewater
loading can be adequately represented by a sinusoidal
relationship with a period of six months, a yearly
cycle would result in an average wastewater loading.
Such an average loading based on average daily flow
has been derived from information in Tables 12 and
13. Figure 10 shows the relationship of full time
and seasonal residents projected by the Therese
Lucas study and the peak population projections
48
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TABLE 12
PROJECTED SEASONAL RESIDENT POPULATION IN SUMMIT COUNTY
1980 1990 2000
Full-time Residents 22,500 34,240 55,800
Dwelling Units 14,300 22,220 29,120
Estimated Seasonal Resident Population* 50,050 77,770 102,095
* Estimated by using projected dwelling units at a density of 3.5 persons per
dwelling unit.
Source: Proposed Water Quality Management Plan
49
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TABLE 13
PEAK SEASONAL POPULATIONS
BLUE RIVER BASIN
Basin 1977 1992
Upper Blue River Basin 20,000 93,000
Snake River Basin 10,000 22,000
Ten Mile Creek Basin 12,000 25,000
Lower Blue River Basin
ill on Reservoir to Willow Creek 17,000 40,000
Willow Creek to Rock Creek 1,000 10,000
U I UC l\
(a) Df
(b) Wi"
TOTAL 60,000 190,000
50
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Projected Populations
Summit County
200
Figure 1O
180
160
8
o
100
D
a
80
60
40
20 H
1970
Daily
Peak Population
E.PA. Report %. J0180,000
^^ «^
Curve A
vF Determined
Average
r Yearly Loading
129,000
Seasonal 102,095
Peak Population A+
90,000
Theresa Lucas
Determined
Minimum
Loading
\-ull-Time
Residents
Therese Lucas
2000
51
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given by EPA in the Water Quality Management Analysis,
To determine an average wastewater loading through-
out a yearly cycle of waste loading, an average
peak population and loading was derived by an
average of the EPA and Therese Lucas seasonal pro-
jections. This is represented by Curve A on
Figure 10. Minimum population and loading was
determined by use of the full time residents pro-
jected by Therese Lucas' study and shown as Curve
B. Average population and loading can thus be
determined for the applicable design periods.
Distribution among the sub-basins was done in the
same ratio as presented in the EPA report and
tabulated in Table 13. Population and wastewater
flow used in reservoir waste loading analysis (not
in treatment plant sizing) are detailed in Table
14.
It must be emphasized that the populations and
wastewater flows given in Table 14 are annual
averages. They are used in the analysis because
of the importance of a yearly cycle of loading on
the reservoir. The wastewater treatment facilities
must be designed to accomodate the daily, weekly,
and monthly fluctuations in wastewater quantity
and composition. In other words, they must be
bigger. That is why, although Table 14 shows a
total annual average wastewater flow of 3.61 MGD,
the proposed plan recommends 6.4 MGD.
LAND USE
A. Historical Land Use
Private land development patterns in Summit County
have been determined to a great extent by the
historical acquisition of private deeded lands. The
land areas below Dillon Reservoir, being free of
timber and covered with native grasses, were
primarily utilized for grazing or for haying while
lands in the upper basin supported mineral mining
operations. Lode claims were developed on tracts
having minimal coverage over the solid igneous
mass of the mountains and having very steep slopes.
Placer claims were developed on glacial deposits
in the upper reaches of streams and rivers and on
stream deposits in the lower valleys.
Public lands have been utilized extensively for
grazing cattle and sheep. Local ranchers drove
cattle from the winter ranges in the lower valleys
to summer ranges in the higher meadows. A larger
number of sheep grazed on the high Alpine ranges.
These activities have diminished as the ranchers
along the valley bottoms converted their lands for
other purposes. Timber harvesting was once active
on the approximately 84,000 acres ofcommercial
forest which consists of Englemann Spruce and
Lodgepole Pine.
Recent pressures for land development in the county
stem from the construction of Interstate 70. and
the Eisenhower Tunnel and the availability of high-
quality winter recreation areas.
B. Existing Land Use
Figure 11 shows existing land use in Summit County.
Land ownership data are tabulated in Table 15 . The
90,775 acres of private land in Summit County can
be classified according to use as non-irrigated
grazing and hay land, irrigated hay land, recreation-
al, residential, and commercial. Agricultural usage
has decreased drastically in recent years and much
of the agriculturally zoned land has been purchased
by speculators. During the rapid development which
has occured since 1970, both commercial and residential
52
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TABLE 14
BASIN
ANNUAL AVERAGE POPULATIONS AND WASTEWATER FLOWS
USED IN RESERVOIR LOADING ANALYSIS
ANNUAL AVERAGE
DESIGN POPULATION
1977 1992
Upper Blue
Snake
Tennri 1 e
Lower Blue
a. Dillon Reservoir to Willow Cr.
b. Willow Creek to Rock Creek
c. Rock Creek to Green Mtn. Res.
11,528 42,973
5,589 9,647
6,987 11,401
9,781 18,417
669 4,385
349 977
ANNUAL AVERAGE
WASTEWATER FLOW, MGD
1977 1992
1.2
0.6
0.7
4.0
1.0
1.1
1.0
0.07
0.04
1.8
0.4
0.09
53
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Land Use
U.S.D.A. Soil Conservation Service/1973 Figure 11
Urban Areas (Industrial, Commercial, Residential,
\_J\ UCL\ I /-AI ^0.0 v. i iv-i^i^jwi i
I Transportation, Airports)
Subdivision Under Development (Lots
Sold and Platted)
Recreation Land
Irrigated Cropland, Pastureland and Hayland
Woodland
Rangeland and/or Non-Irrigated Pastureland
54
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TABLE 15
SUMMIT COUNTY LAND OWNERSHIP
Hectares Acres
Public Lands -- Total 117,860 291,116
a. Federal Lands -- Total 117,602 290,476
U.S. Forest Service 111,043 274,278
Bureau of Land Management 3,945 9,774
Other Federal Agencies 2,600 6,424
b. State of Colorado 129 320
c. Summit County 129 320
Private Lands Total 36,751 90,775
a. Subdivisions Outside Incorporated Limits 2,717 6,710
b. Incorporated Areas 1,377 3,400
c. Coal and Oil Reserves 1,378 3,404
d. Agricultural Lands, Mining & Placer 31,280 77,261
56
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developed lands have been recreation-oriented as
evidenced by large numbers of tourist shops,
restaurants, motels, and seasonally occupied con-
dominiums. Construction-related light industry
1s to be found 1n developing areas.
Agricultural land, occupying just under half of
the county"s 90,775 acres of private lands, is
located primarily below (north of) Dillon Reser-
voir. Virtually all the agricultural activities
consist of cattle ranching and haying. In recent
years ranching in Summit County has steadily de-
clined as progressively stricter grazing policies
have been placed in effect on the public lands
which surround the farms. Since T930 the number
of farms has decreased from 61 to 25, and the
head of cattle from 8,690 to less than 4,200. As
farming has become less profitable and land more
valuable, total private farm acreage decreased
from a high of 50,772 in 1959 to a low of 27,600
by 1969.
Mining activity, which at one time supported a full
time Summit County population of over 8,000, is no
longer a predominant factor in the local economy.
Present activities are confined to mining of moly-
bednum ore at Fremont Pass by AMAX, Inc. The
residue from the milling operation is retained in
tailing ponds located in Robinson Flats, Summit
County, and is discharged to Tenmile Creek. The,
evidence of past activity, however, is still abun-
dant throughout the upper basin where old tailing
ponds, large stretches of rockpiles, and gold
dredge spoil sites mark the landscape. AMAX is
planning to expand its operations by developing
the Henderson Mines.
Recreation activities in Summit County are season-
al in nature and take place for the most part on
public lands. Wintertime activities are the most
popular and skiing exhibits the greatest number
of participants. Summer recreation activities,
e.g. boating, hiking, fishing and sight-seeing,
have a significant number of participants which is
increasing annually. Commercial, residential and
light industrial use of private lands in the County
primarily supports recreational activities on the
public lands - Arapaho National Forest and Dillon
and Green Mountain Reservoirs.
All existing ski areas are located in the Dillon
Reservoir Watershed, as are_all but one (Ptarmigan)
of the ten potential ski sites evaluated by
the U.S. Forest Service. 'Hence, residential
development in this area, of which condominium
units comprise well over 5Q% of the housing stock
and a very high percentage of the units are
offered as second homes, are for the most part
occupied during the winter season with the highest
occupancy rates occurring on weekends and holidays.
Another factor contributing to the occurrence of
population peaks in the Dillon Reservoir Water-
shed on winter weekends and holidays is the proxi-
mity of the area to Denver and the Colorado Front
Range Corridor and the fact that people from
these areas constitute 66% of the condominium
owners in Summit County, while less than 1Q% of all
the owners are County residents. Not to be over-
looked is the retirement community aspect of much
of the development. Condominium buyer profiles
indicate that the typical buyer is viewed by
developers as being in his low to middle forties;
having an income In the $30,000 to $40,000 range,
and working in a professional occupation.
57
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Recreational land use in the Blue River Basin below
Dillon Reservoir is expected to be concentrated in
areas adjacent to the Blue River since other areas
are unsuitable. The reasons for this statement are
different for the eastern and western sections of
the lower basin. The western section is character-
ized by streams flowing into the Blue River from the
Gore Range Mountains which typically have hung valleys
developed by glacial erosion. The valleys afford
difficult accessibility to vehicular traffic and
campsites while power-driven vehicles are prohibited
In the Gore Range-Eagles Nest Primitive Area. The
Williams Fork Mountains to the east of the lower
Blue River are more barren and bleak, especially at
the lower elevations where the weak sedimentary
formations are predominant. All the valleys drain-
ing into the Blue River from this range of mountains
have intermittent stream flows with the exception
of two streams which maintain some minimal flows.
The watersheds are comparatively small, have westerly
exposures, and are sparsely timbered. Users of the
lower basin Forest Service camping facilities
generally exhibit a fairly stable population through-
out the summer season.
In summary, land use in the southern portion of the
County - the Dillon Reservoir Watershed - is primar-
ily oriented towards winter recreational use which
is subject to peaks corresponding to holidays and
weekends. In 1970, over 85% of the subdivided
acreage was located in the upper basin and most of
the development continues to be concentrated in
this section. There also exists a significant
amount of summer recreational use of Dillon Reser-
voir and this usage should increase in the future.
The northern portion of the County - the watershed
of the Blue River below Dillon Reservoir - is and
will continue to be utilized predominantly for
summer recreational activities.
C. Land Use Regulations
1. Local Regulations
The following towns are incorporated areas of Summit
County having their own zoning regulations:
Frisco
Dillon
Silverthorne
Breckenridge
Blue River
In 1970 the total acreage of town tracts in Summit
County was 1,308. A current (1974) estimate of
the incorporated area of the County (total acreage,
including roads) is 3,400 acres. The latter
estimate does not include proposed township an-
nexations which total over 1,000 acres. The amount
of incorporated areas of the county is significant
due to the lack of density limitations in the zoning
classifications. The lack of unit density restrict-
ions for hotels, motels, lodges, apartments and
condominiums is particularly evident. The blanket
zoning regulations of the townships do not provide
constraints on construction based on environmental
considerations such as: slope, flood plains, poorly
drained lands, thin soils, exposure or soil stab-
ility.
Even if more restrictive zoning regulations were
legislated by the several townships, it is not an
extended period of time. Zoning regulations are an
integral part of municipal politics and Summit County
would be particularly vulnerable to pressure for
change due to both the shortage of developable
land and the high percentage of absentee owners.
The resident population and their elected represen-
58
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tatives would consist primarily of persons owning
or employed by the local businesses which are depen-
dent on recreational developments for their income.
2. County Regulations
As of September, 1974 there were 90 active subdiv-
isions in the unincorporated areas of Summit County.
The total acreage of these subdivisions was 4,920.
This acreage was subdivided into 4,822 lots of which
4,100 were zoned single family. However, a total
of 12,962 units was approved. In addition, ap-
proved residential zoning in unincorporated areas
as yet not subdivided totals 8,892 units on 1,790
acres.
In summary, for the unincorporated areas which
must meet Summit County Zoning Regulations:
Total Acres Platted and/or Zoned 6,710
Total Units Approved by Zoning 21,854
Most of the subdivision development is occurring
in the fringe areas of the existing townships with
additional concentrated developments in the Swan
River, Copper Mountain, Keystone, Summit Cove and
Hoosier Pass areas.
Of the lots platted, most are zoned rur single fam-
ily units. Costs for sewer and water line construc-
tion are expensive due to topographical and climatic
constraints which were described in previous sec-
tions. However, experience has shown that the pri-
vate sector is willing to pay these costs.
Comprehensive planning has had little public sup-
port. In September, 1971, Gathers and Associates
submitted a preliminary comprehensive plan to the
County Commissioners. This plan was concerned
primarily with the Upper Blue River Basin but due
to zoning conflicts between the Gathers Plan and
township-use plans, it was never adopted. In 1963,
Sam L. Huddlestone submitted a plan entitled "Summit
County, Colorado: The Master Plan." Although the
plan was generalized with zoning regulations designed
to prevent dense development on meadows and open
areas, the zoning and subdivision regulations were
deleted prior to acceptance. The existing County
zoning regulations were adopted in 1969.
Existing zoning regulations do not allow dwelling
unit densities greater than 15 units per acre. The
Planned Unit Development (PUD) zoning classification
was adopted in 1973. Due to the multitude of con-
straints associated with high altitude, mountainous
construction activities, the PUD concept is desir-
able since it allows dwelling units to be clustered
in the areas suitable for construction. The clus-
tered development is also more readily serviced with
public utilities resulting in monetary savings and
reduced environmental damage. Regulation of con-
struction activities was initiated in 1970 when the
Uniform Building Code was adopted.
The Regional planning Commission (RPC) was formed
in 1970 in response to Chapter 106 of the Colorado
Revised Statutes. The RPC, acting as the County
Planning Commission, reviews development proposals
and makes recommendations to the Board of County
Commissioners. The RPC is assisted by three full-
time planners who review new development proposals
and continually work on a County Master Plan.
It is evident that although county and township
officials have moved toward the adoption of more
59
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restrictive zoning regulations, land speculations
has been occurring in the County for more than a
decade. Thus, presently within the County, includ-
ing the townships, approximately 42,000 units have
been approved by zoning and the greater portion of
these units are located in the Dillon Reservoir water-
shed. The 42,000 approved residential units are
located on a total of 10,000 acres of residential-
zoned land.
3. State Regulations
The trend in Colorado land use regulation has been
to delegate authority and financial aid to the local
governments for the purpose of enacting legislation
specific to local requirements. Chapter 106 of the
Colorado Revised Statutes, which includes House Bill
1041 and 1034 and Senate Bill 35, gives the Board
of County Commissioners the authority to regulate
the use of land.
House Bill 1041 provides local government with the
authority to identify, designate and regulate speci-
fied areas and activities of State interest. H.B.
1041 also provides procedures for the Colorado Land
Use Commission to initiate the identification and
designation of areas and activities of State inter-
est and to intervene in situations where land dev-
elopment activities present a danger to the public
health and welfare. The effectiveness of this law
is yet to be determined. It has been criticized
for the broad exemption of certain developments
and its cumbersome administrative procedures.
Summit County has proposed that the area alongside
the Lower Blue River between Silverthorne and Rock
Creek be declared an "area of state interest" and
therefore be subject to the land use regulations
of such areas. This area, approximately 18 miles
long and 1/2 to 2 miles wide, has for the most part
been acquired by land speculators. It should be
noted here that, even with such a designation, the
land could be developed if it was previously zoned
residential. (Bermingham, 1974).
H.B. 1041 makes available $50,000 over a two-year
period (1974-1975) for a county-wide comprehensive
plan. A comprehensive plan is expected to be com-
pleted soon and emphasis at present is on basin plans
for the Lower Blue River Valley, and the Snake River
Valley. Work is proceeding with the cooperation of
the U.S. Forest Service.
House Bill 1034 grants local governments the auth-
ority to plan and legislate the control and limit-
ation of the "location and amount of population
growth and of density of population in particular
areas." It also gives the local government substan-
tial control of land use in hazardous areas, high-
ways corridors, land critical to wildlife, scenic
areas and agricultural lands. To date the growth
limiting provisions of this bill have not been im-
plemented in Summit County.
Senate Bill 35 sets minimum requirements for county
subdivision regulations including water, sewage
and soil data requirements to be supplied by
developers. The provisions of this bill have been
incorporated into the "Summit County Subdivision
Regulations." These subdivision regulations, while
limiting development within the 100-year flood plain
do not effectively restrict growth through any other
requirements.
4. Federal Regulations
The primary agency responsible for land use regula-
tions in Summit County on the Federal level is the
60
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U.S. Forest Service.
National Forest lands in the County constitute 76
percent of the total acreage. These lands are ad-
ministered by the Forest Service and are managed
under principles of multiple use to produce a
sustained yield of products and services, as auth-
orized and directed by the Multiple Use Act of
June 12, 1960. This Congressional Act directs that
the National Forests shall be administered for out-
door recreation, range, timber, watershed, wildlife,
and fish purposes.
The Forest Service manages recreation at approxi-
mately 16 facilities in the County and on Denver
Water Board lands and will probably take over
jurisdiction of BLM lands in the County. At pre-
sent, a Unit Plan is being formulated by the Forest
Service for the Snake River Basin. An environmental
impact statement has been prepared by the U.S.F.S on the
plan. Future plans will be completed for other
Forest Service lands in the county. In addition,
the Forest Service proposes to establish a Green Belt
along the Blue River between Silverthorne and Green
Mountain Reservoir to produce additional space for
campgrounds. This proposal has been under considera-
tion since 1970.
An important regulatory function of the Forest Ser-
vice in Summit County is its jurisdiction of exist-
ing ski slopes and its evaluation and approval of
potential slopes. When proposed expansions of the
four existing ski slopes in the County (A-Basin,
Breckenridge, Keystone and Copper Mountain) are com-
pleted, slope capacity will total about 35,000 to
40,000 on a peak day. Use of Forest Service land is
generally restricted to the ski slopes and lift
61
equipment. However, construction of privately-owned
commercial facilities on National Forest land is
allowed in specific instances through the acquisi-
tion of a "Special Use Permit." An example is Key-
stone Lodge in the Snake River basin.
As of 1973 ten potential ski areas have been evalua-
ted by the Forest Service. Nine of these areas were
in the Dillon Reservoir Watershed and five areas
were rated as " good." Forest Service approval for
development generally requires the developer to
present a two-year study of snow conditions and a
master plan for the ski area. This is followed by
the preparation of an EIS by the Forest Service.
There has been a significant amount of trading of
Forest Service lands along the valley bottoms for
private lands located in the upland regions. These
private lands are for the most part mining and placer
claims which in many cases are inaccessible by road
and are surrounded by National Forest. Mining and
placer claims total 41,099 acres or 45 percent of
the private land in the County. Development of
these isolated tracts of private land would require
Forest Service approval for transportation and util-
ity rights-of-way. Whether or not this approval can
be withheld is a legal matter which would be sub-
ject to adjudication.
D. Projected Land Use Patterns
The land use trend for the Dillon Reservoir Water-
shed, in which development pressures are currently
the greatest, is the build-out of all available
private lands. The pattern of private land hold-
ings in the upper basin has been determined by the
historical mining activities, the criteria for
which do not correspond to development criteria for
recreationally-oriented residential and commercial
-------
activities. Consequently, continued trades of in-
accessible private tracts surrounded by U.S. Forest
Service land for isolated Forest Service tracts lo-
cated in the valley bottoms can be expected. These
trades would be facilitated by the fact the access
to inaccessible private tracts cannot be denied and
rather than permit a proliferation of access roads
and utility lines, the Forest Service would prob-
ably be willing to dispense with its valley-bot-
tom lands.
Public land areas presently inaccessible, but which
may be developed in the future, would be the four
potential ski areas in the upper basin which have
been rated "good" by U.S. Forest Service appraisals.
Three of these areas -- North Barton, Wise Mountain,
and Swan Valley -- are in the upper reaches of the
upper Blue River sub-basin while the fourth area
Independence Mountain is in the Snake River sub-
basin. Sufficient acreage is available in and
around the surveyed areas, albeit in fragmented
tracts at the Snake River site, to afford sub-
stantial peripheral residential and commercial
development on private lands.
It can be expected that the substantial areas of
undeveloped private lands adjacent to the Dillon
and Green Mountain Reservoirs will come under
increasing development pressure. Unless the land
alongside the lower Blue River between the two
reservoirs is classified as an "area of state
interest" or is incorporated into a proposed
Forest Service administered green belt, it is
likely that summer recreation-oriented development
will result since much of the land has already been
acquired by speculators.
There exists in the incorporated areas of the County
a significant trend of increasing township area
through annexation. With the exception of Silver'
thorne, all of the incorporated areas are in the
Dillon Reservoir Watershed. To the extent that
undeveloped land is incorporated into townships,
increasing development pressures will result. Com-
prehensive County Plans for land use, transporta-
tion and sewerage, which have not found widespread
support in the past, may encounter increasing dif-
ficulty in gaining a concensus.
HISTORICAL AND ARCHAEOLOGICAL RESOURCES
Summit County, once a significant "hard rock" min-
ing area for the State of Colorado, is full of his-
torical places. Detailed information can be ob-
tained from the Summit Historical Society in Dillon.
Even though EPA's approval of a water quality man-
agement plan for the County does not involve a com-
mitment to construct any projects, the National
Register of Historic Places, published monthly in
the Federal Register by the National Park Service,
was consulted. No listings were found for Summit
County.
As wastewater treatment projects are proposed for
construction under Section 201 of the Federal Water
Pollution Control Act as amended, more detailed
investigations (surveys,salvage) concerning pos-
sible impacts on historical and archaeological
sites will be conducted, as required by Section 106
of the National Historic Preservation Act of 1966.
Executive Order 11593, and the Archaeological and
Historic Preservation Act of 1974.
62
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TRANSPORTATION
Summit County is served by two major highways, State
Highway 9, and Interstate 70 (U.S. 6) (Figure 2).
These traverse the county in north-south and east-
west directions, respectively. Plans are now being
finalized by the Colorado Division of Highways for
the completion of Interstate 70 through the county,
from Frisco to Wheeler Junction. An EIS on this
project has been prepared by the Division of High-
ways, and should be consulted for further informa-
tion. In addition, another important part of the
Interstate 70 project, the Second Bore of the Eisen-
hower Tunnel, will soon be constructed. The reader
is also encouraged to refer to the EIS which has
been prepared by the Division of Highways for this
project. With the completion of Interstate 70, use of
the county's ski areas has increased dramatically.
Additional service for motor vehicles is provided by
numerous county-maintained roads, as well as roads
constructed on U.S. Forest Service lands.
No commercial (regularly* scheduled) air service
is available in the county.
RECREATIONAL RESOURCES
A. Ski Areas
There are four major ski areas in the County. These
are Arapahoe Basin, Breckenridge, Copper Mountain
and Keystone. All are situated in the Arapaho
National Forest. The Forest Service has surveyed
another eleven sites; eight sites were rated mar-
ginal to good, and three were unacceptable.
Skier visitor trends for the basin have increased
by an annual average rate of 19.8 percent since
1961. If trends continue at this level, the total
could reach 1.2 million by 1980 and over 2 million
by 1990. However, in view of the present unfavor-
able economic climate, and the fact that skiing
is an expensive sport, it is possible that the
growth in skiing trends will not continue at
these high rates. Additional information concern-
ing the use of these facilities was presented under
"Land Use." Table 16 summarizes use of ski areas
in the county.
B. Dillon and Green Mountain Reservoirs
Recreation facilities available at Dillon and
Green Mountain reservoirs are shown in Figures 7
and 8. Dillon Reservoir is a major recreational
attraction in the basin during the warmer months.
It has 25 miles of shoreline with recreational sites
operated by the Forest Service. These include camp-
grounds, several picnic areas, and boat launching
ramps. No water skiing is permitted on the reservoir.
There is a small marina at the town of Dillon.
At Green Mountain Reservoir, five campgrounds are
available, administered by the Colorado Department
of Natural Resources. Water skiing is permitted
here. During the winter, snowmobilUng and ice fish-
ing are permitted on both reservoirs.
In 1971 the usage of the recreational facilities at
Dillon Reservoir, a total of 324,800 visitor days,
increased 16.2 percent over that in 1970 and 491
percent since 1966. In recent years the annual in-
creases have declined somewhat, indicating that
facilities are reaching saturation.
63
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TABLE 16
USE OF SUMMIT COUNTY SKI AREAS
Arapahoe Basin
Breckenridge
Copper Mountain
Keystone
TOTALS
% Increase
Daily Average*
Visits
70-71 Season
Skiers All Users
Visits
71-72 Season
Skiers All Users
Visits
72-73 Season
Skiers All Users
Visits
73-74 Season
Skiers
107,200
200,600
73,600
381,400
21.6
3,178
112,500
209 ,300
76,700
398,500
3,321
94,700
221,500
700
148,600
465,500
22
3,879
184,600
288,700
700
151,700
625,700
6,048
89,400
271,200
120,500
146,000
627,100
34.7
5,226
90,400
272,200
121,100
155,900
639,600
5,330
98,000
282 ,800
181,900
173,400
736,100
17.4
6,134
*Assuming a season of 120 days
Source: U.S. Forest Service, Denver, Colorado
64
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The availability of water-based recreational fac-
ilities, centered primarily on Dillon Reservoir,
has added enormously to the growth potential of the
County, since these form the nucleus of summer rec-
reational activities. These together with skiing
and other winter sports, provide for year-round rec-
reational opportunities, which is one of the major
factors fostering the surge of second-home develop-
ment in the area.
C. Year Round Resorts
The recreation industry is developing resorts centered
around ski sites but providing year round recrea-
tional opportunities as well.
The Four Season Village, a $52 million complex near
Breckenridge, offers year round recreation. This
resort is based at the foot of Peak 9, which when
completed will include 935 acres of ski runs and
trails. In addition to a full range of winter sports,
various summer activities - hors*eback riding,
archery, trap and skeet shooting-are available.
Keystone, east of Dillon, is another year round re-
sort. It opened for the 1970-71 ski season and the
projected expansion over the next 15 years will
involve an investment of over $100 million. In
addition to a full range of winter sports, summer
recreational activities will center around the Snake
River and Dillon Reservoir.
D. Additional Recreational Resources
Lands administered by the U.S. Forest Service in
Summit County offer a wide variety of recreational
resources, such as camping, hiking, backpacking,
and cross-country skiing. The District Ranger's
office in Dillon should be contacted for additional
information concerning these opportunities.
SENSITIVE ENVIRONMENTAL AREAS
As development proceeds in Summit County, special
attention must be given to avoiding land use con-
flicts with environmentally sensitive areas. These
include floodplains, avalanche areas, alpine tundra,
fire hazard areas, and the scenic resources of the
county. Limited data are available at the present
time concerning some of these areas. However, the
Summit County Planning staff is currently compiling
exactly this type of information for the preparation
of their comprehensive plan, as required by H,B. 1041
(See "Land Use"). The U.S. Forest Service and other
government agencies are cooperating with the county
1n collecting and analyzing this information.
Summit County planners have delineated
the floodplain for the Blue River through the town
of Breckenridge, and at Farmer's Corner (near
the Breckenridge wastewater treatment plant). A
"flood-prone area", which more or less serves as
. .. . . a red flag to potential developers, has been de-
Copper Mountain, at Wheeler Junction, 1s the remaining signated on the lower Blue River through the town
major year-round resort 1n the county. This multi-
mil T ion dollar complex will have an eventual cap-
acity of 10,000 skiers per day and includes lodges,
condominium units, a conference center, and various
sport facilities (swimming pools, tennis courts,
playing fields}. It also includes
and employee housing.
a shopping center their development.
65
of Silverthorne, and for some distance downstream.
The remainder of the Blue River 1s currently being
evaluated by the County Planning Office. The
developers of the Keystone resort have delineated
flood hazard areas of the Snake River as It affects
Similar work has been done at
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the Copper Mountain resort (Tenmile Creek). Plan-
ning for the construction of 1-70 through Tenmile
Canyon has considered flood hazards from Tenmile
Creek.
Avalanche Areas: Summit County has this hazard
in common with most mountainous areas. The U.S.
Forest Service and the County are cooperating in
studies which will be used in the county's com-
prehensive plan, and Forest Service impact state-
ments and Unit Plans. Examples of avalanche areas
which have been identified to date include all of
Tenmile Canyon; the west side of the Tenmile Range;
the west approach to the Eisenhower Tunnel; and
the Love!and Pass.
Alpine Tundra: The Alpine Tundra is an extremely
fragile ecosystem. It is found above the timber-
line at elevations above 11,500 feet. The subsoil
may be permanently frozen and in many areas snowfields
remain year round. Thus only the hardiest species
can survive there. The vegetation consists primarily
of lichens, mosses, grasses and sedges, and stunted
shrubs, but during the brief growing season annuals
bloom in profusion. Summit County's work on the
development of a comprehensive plan will address
these areas in terms of whether or not developable
lands are available, according to environmental
constraints.
Fire Hazard Areas: The U.S. Forest Service has
delineated general wildfire areas in Summit County
as those which combine dense tree cover with slopes
of 30% or greater. Additional work will be factored
into the county's comprehensive plan. Fire protec-
tion in the county is generally less than adequate
to cope with this hazard.
Additional Sensitive Areas:
1. Proposed Wilderness Area -- Eagle's Nest:
Official wilderness status and protection has been
proposed for this area, currently classified by
the Forest Service as a "primitive area". Acreages
proposed for inclusion into the official wilderness
area range from 87,000 (proposed by the Administra-
tion) to 128,000 (proposed by environmental groups).
A major point of contention revolves around plans
of the Denver Water Board, which hopes to utilize
waters from this area to provide more water to the
Denver area.
2. Potential Scenic Highway: The Summit County
Commissioners have recommended to the Federal High-
way Administration that U.S. Highway 6 from Love-
land Pass to the Interchange with 1-70 at Dillon-
Silverthorne be classified as a scenic highway.
3. Visual Analysis; The Summit County Planning
Department has completed a visual analysis of the
entire county. This should assist developers and
the county in avoiding development in areas that
have special scenic attractiveness. This -analysis
is available on request from the county.
Concerning the future planning and construction of
wastewater treatment facilities, any projects which
are under consideration for Federal financial assis-
tance must consider environmental constraints and
hazard areas such as those identified in this section.
66
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67
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68
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Alternatives
DESCRIPTION OF ALTERNATIVES
OBJECTIVES
In developing the proposed Water Quality Management
Plan for the Blue River Basin, various alternatives
for controlling point sources of sanitary wastewater
(sewage) were considered. Factors taken into account
during this analysis include technical considerations,
social and economic constraints, and environmental
effects. The following objectives for water quality
management planning were utilized:
1. Maintain or enhance water quality of Dillon and
Green Mountain Reservoirs;
2. Assure compliance with applicable stream water
and effluent quality standards;
3. Utilize existing facilities to the extent pos-
sible;
4. Maximize economics of advanced treatment and
sludge handling, treatment, and disposal, by region-
al ization;
5. No construction of raw sewage force mains in
the immediate vicinity of the reservoirs.
A. No Action
EPA could decide not to approve the proposed water
quality management plan at this time. However,
this would be a short-term decision, since Section
303(e) of the Federal Water Pollution Control Act
Amendments of 1972 requires the submission of basic
plans to EPA under a continuing planning process. In
addition, "no action" would clearly not satisfy the
objectives stated above.
A possible modification of the "no action" alterna-
tive would be the disapproval of the proposed plan
(already approved by the State of Colorado), with
the recommendation that an alternative form of the
plan be resuomitted to EPA for further consideration.
Because the law requires EPA to approve a plan, the
proposed plan for the Blue River Basin will either
be approved, or resubmitted in a different form for
re-consideration. Since the possible different forms
of the plan would most likely involve structural
alternatives to that proposed, the following por-
tions of this chapter will concentrate on these al-
ternate strategies for treating point sources of
domestic sewage in the basin.
B. Alternative Structural Strategies
The Water Quality Management Plan considered six
alternate strategies for arranging wastewater
treatment facilities in the basin. These are
shown in Figure 12. Summaries of the features of
each alternative are presented in Table 17. Appen-
dix "G" contains a detailed description of each
alternative. Alternate 6 is proposed for EPA's
approval.
69
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Alternate Strategies
Figure 12
Legend
5JC Secondary Treatment
Advanced Wastewater
Treatment
Alternative 2
Alternative 1
Interceptor Sewers
Force Main
70
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Alternative 4
71
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Alternate Strategies Cont'd
Alternative 5
Alternative 6
72
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Note from Figure 12 that all six alternatives call
for the construction of several secondary treat-
ment plants in the area of, and downstream from,
Green Mountain Reservoir. The plan does not specify
the exact number of facilities for this area. Figure
12 shows three facilities as a likely configuration.
Similarly, all except Alternative No. 4 indicate
two advanced wastewater treatment (AWT) plants along
the lower Blue River between Dillon and Green Mount-
ain Reservoirs (Rock Creek and Dillon-Silverthorne
sites). The alternatives are thus different mainly
in the manner in which wastes from the upper water-
shed (Dillon Reservoir watershed) could be managed.
The screening process used in selecting (and elimin-
ating) alternatives concentrated on solutions to
wastewater treatment problems in the Dillon Reser-
voir area because 1) most of the population in the
basin is in the upper watershed, and 2) Dillon Res-
ervoir is the most critical receiving water in the
basin from a water quality standpoint.
Considering treatment facility needs for the upper
basin, several basic themes are apparent in the
six possible structural alternatives:
1. Transport all wastes gut of the upper basin:
Alternative 2 accomplishes this. Partial treat-
ment would be provided at some of the existing
sites, and these wastes would be taken downstream
of the reservoir for more treatment and discharge
to the Blue River. No discharge would be allowed
to Dillon Reservoir.
2. Transport some of the wastes out of the basin:
Alternatives 3, 4, and 5 involve various combina-
tions of existing plants, modified plants, and
interceptor sewers to prevent most wastewaters
from the upper basin from entering Dillon Reser-
voir. Only wastes which have been subjected to
AWT would enter the reservoir, and these would
constitute a small percentage of the total wastes
generated in the upper basin.
3. Treat all wastes from the upper basin, with dis-
charge to Dillon Reservoir or its tributariest Al-
ternatives 1 and 6 recommend this course of action.
Alternative 1 would phase out some existing plants
and treat all wastes from each sub-basin near Dil-
lon Reservoir, while Alternative 6 would utilize
existing facilities, avoiding some regionalization.
All treatment plants proposed for Alternatives 1
and 6 for the upper basin would be AWT.
Despite the great differences in these three pre-
dominant themes, they do have something in common;
all proposals for the upper basin (wastes from the
Snake, upper Blue, and Tenmile sub-basins) will
provide a total treatment capacity of approximately
4.3 MGD. Adding to this the proposed capacity of
a facility at the Silverthorne site, the total
sewage treatment capacity for the most heavily-
used portion of the basin comes to about 6.0 MGD.
This is enough capacity to treat wastes generated
by approximately 60,000 persons, assuming that
each person supplies about 100 gallons per day
to the treatment system, and allowing for some
infiltration into the system. Note, however, that
these flow capacities are projected only to 1977.
In essence, then, the six alternatives proposed in
the Water Quality Management Plan primarily address
questions relating to siting of treatment plants
and discharge locations, and the level of treat-
ment required at each site. Future plans for the
basin (primarily the 208 Areawide Plan and future
"facility" plans for individual treatment plants)
will consider the sizing of the facilities into
the future.
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TABLE 17
COMPARISON SHEET
STRUCTURAL ALTERNATIVES
a. AWT Upper Blue River Basin
b. AWT Entire Snake River Basin
c. AWT ~ Entire Tenmile Creek Basin
d. AWT At existing Silverthorne site
e. AWT For area between Green Mountain Reservoir
and Silverthorne site
f. Secondary treatment For area adjacent to
Green Mountain Reservoir
g. Secondary treatment For area between Green
Mountain Reservoir and Colorado River (several)
h. Secondary treatment For Upper Blue River Basin,
with force main to Frisco
i. Secondary treatment For Snake River Basin, with
force main to Silverthorne
j. AWT -- For Tenmile Creek Basin upstream to
Wheeler Junction
14
=«*=
5
X
X
X
X
X
X
ro
=«=
C C
t- S_
QJ O)
5 5
X
X
X
X X
X X
X
X
vo
*«=
ro
i-
0>
+J
5
X
X
X
X
X
X
74
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k. Secondary treatment For Tenmlle Creek Basin,
with force main to Silverthorne for Upper Blue
River Basin and Tenmile Creek secondary effluent
1. Secondary treatment For Snake River, upstream
to confluence with North Fork
m. AWT For Arapahoe Basin (ski area)
n. Secondary treatment For Tenmile Creek Basin,
upstream to Wheeler Junction
o. AWT For Tenrm «e Creek Basin upstream from
Wheeler Junction
p. AWT -- Upstream from Green Mountain Reservoir,
for all wastes from upstream areas
q. Secondary treatment For Tenmile Creek Basin,
with force main for effluent to Silverthorne
r. AWT For Snake River Basin upstream to confluence
with North Fork
*~ ' CM CO ^- ir>
*=«*.«*, 5= ^
4J ^> 4^>
X
X X
X X
X X
X X
X
X
Alternative #6
X
X
X
75
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Of the five objectives listed on page69 for screening
alternatives, the final one (no construction of raw
sewage force mains in the immediate vicinity of the
reservoirs) was the most influential in eliminating
alternatives. Since Alternatives 2, 3, 4, and 5 in-
volve exactly this type of proposal, they were elimi-
nated from further consideration. A primary factor
in this decision is the possibility of a break in
such a line, which could allow tremendous amounts
of raw or inadequately treated sewage to enter Dil-
lon Reservoir, which provides Denver with drinking
water. Further, the high costs of sewer construction
in this mountainous area adds another serious disad-
vantage to these four alternatives.
Additional problems with Alternatives 2,3,4, and 5
include: l)constraints of water rights owned by the
Denver Water Board; 2)problems with possible eutro-
phication of Green Mountain Reservoir if all wastes
are discharged below Dillon Dam; and 3)the constraints
of cost-effectiveness of constructing long intercep-
tor sewers and force mains*
The remaining two structural alternatives proposed in
the Plan (1 and 6) both involve the direct discharge
of wastewater into Dillon Reservoir or its tributaries.
Alternative 1 involves more consolidation of facili-
ties than Alternative 6, as well as the construction
of interceptor sewers all the way into the upper
reaches of each sub-basin in the upper watershed.
Primarily because of the high costs of sewer con-
struction in the area, Alternative 1 was eliminated.
An additional factor in this decision was meeting
Objective Number 3 on page69 , which calls for "util-
izing existing facilities to the extent possible".
Alternative 1 would necessitate the abandonment of
the A-Basin and Copper Mountain plants, and would
require extensive upgrading and expansion of the
other facilities in the upper basin.
Cost comparisons for the six alternatives are pre-
sented in Table 18.
TABLE 18
ALTERNATIVE
COST COMPARISON OF
ALTERNATIVES (1977)
TOTAL
CAPITAL COST
TOTAL
ANNUAL COST
Alternative No.l
Alternative No.2
Alternative No.3
Alternative No.4
Alternative No.5
Alternative No.6
$ 5,564,000
$ 8,237,000
$ 6,067,000
$17,814,000
$ 7,867,000
$ 5,301,000
$ 617,000
$ 944,000
$ 706,000
$2,027,000
$ 903,000
$ 592,000
The above costs are for those facilities which
do not yet exist, but which the plan says will
be required by 1977. The costs do not include
the facilities shown in Figure 12 which would
be located below Silverthorne, since these will
not be required until after 1977. It should be
noted that these cost estimates are due for re-
vision, since some treatment facilities called
for in the plan have already been constructed, using
funds other than Federal. In addition, planning
76
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for the upgrading of some facilities in the basin
(Summit County Phase "D"; Dillon-Silverthorne; and
Frisco) is now underway. More detailed cost estimates
will be available as these plans are finalized.
C. Alternatives to Discharge into Reservoir Arms
As shown in Figure 12, the proposed alternative (6)
calls for the direct discharge of treated wastewater
into Dillon Reservoir or its tributaries. As noted
in Chapter 2, this is the current practice in the
basin, and it is leading to the slow eutrophication
of the Reservoir. The arms of the reservoir have
been shown to be the most sensitive areas, while
the main body of the reservoir is less susceptible
to this problem, to reduce the problem of eutrophi-
cation in the arms, consideration has been given to
directly discharging wastes from the Dillon Reservoir
watershed (following advanced treatment) to the main
body of the reservoir.
This alternative has been eliminated for two reasons:
1) In case of a major plant failure, inadequately
treated wastes would be discharged into the main
body of the reservoir if this alternative were im-
plemented. Since the intake structure for the Den-
ver Water Board's Roberts Tunnel is located in this
area, the risk of contaminating the water supply
of Denver must be considered.
2) This alternative would involve extensive under-
water piping to transport the treated sewage effluent
to the main body of the reservoir. The economics
of this construction are not acceptable to the lo-
cal interests at this time.
D. Flow and Waste Reduction Measures
If less wastes were generated in the basin, smaller
and fewer facilities would be required for their
treatment. To some extent, the waste load alloca-
tions for Dillon Reservoir encourage flow and waste
reduction measures, by placing an upper limit on
the amounts of waste which may be introduced. As
facility plans for individual treatment works in
the basin are proposed, full consideration will be
given to additional means of reducing the volumes
of sewage introduced into treatment works. These
measures will include reductions in the amount pf
infiltration and inflow, and implementing a pro-
gram of household water conservation. Because of
the common practice of leaving faucets on during
the winter to prevent pipes from freezing, the
latter may be especially important. However,
such measures would not eliminate wastes in the
basin, and cannot thus be considered as full al-
ternatives to the implementation of a water quality
management plan.
E. Wastewater Re-use
The concepts of re-using treated wastewaters generally
involve such possibilities as re-use by industries;
creating recreational lakes; or groundwater recharge,
In the Blue River Basin, such uses are limited. There
are no large water-using industries, and sites for
the development of more recreational lakes would
probably be hard to find. Further, complications
would arise because of adjudicated water rights.
F- Land Application
The proposed Water Quality Management Plan has dis-
cussed the possibility of land application of some
or all of the wastewater effluents generated in the
basin. Briefly, this alternative to the surface
disposal of wastewater in Dillon Reservoir, its
77
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tributaries, and the Blue River, was eliminated
because:
1) There is not much cultivated land in the basin;
2) . Suitable soils for land disposal are not avail-
able;
3) The climate would limit the application of efflu-
ent to the land from May to September, and storage
of effluent would be required during other parts of
the year. Unfortunately, the "other parts of the year"
also happen to include the ski season, when most
wastes are generated in the basin.
4) Complications would arise involving water rights
in the basin.
It is the general policy of EPA to encourage land
application of effluent wherever possible. However,
land application should not be viewed as a panacea
to water pollution problems, as it often creates pro-
blems of its own. -As individual facility plans are
prepared for projects in the Blue River Basin, land
application of effluent will be given full considera-
tion.
G. Sludge Disposal
The proposed "Water Quality Management Plan recommends
that the current practice of landfill ing sludge from
the county's wastewater treatment plants be continued
until such time as a new site for sludge treatment
and disposal can be decided upon. The plan does not
recommend such a site. However, the plan does dis-
cuss in some detail many of the optional ways of
sludge treatment and disposal, including land dis-
posal, incineration, reclamation for sale, and trans-
port out of the basin.
These alternatives will be considered in more detail
as individual facility plans are prepared for pro-
posed wastewater treatment projects in the county.
78
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79
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IV
Proposed Plan
GENERAL
Details of the proposed Water Quality Management
Plan for the Blue River Basin are outlined in the
plan itself, which, by reference, is included as
part of this EIS. The major features of the plan
are outlined below.
TREATMENT FACILITIES
Alternative Number 6 (see Chapter I) describes
wastewater treatment facilities which should be con-
structed in the basin to meet water quality manage-
ment planning objectives. Many of these facilities
are already in operation, under construction, or in
the detailed planning stages. Compare Alternative 6
(Figure 12) with Figure 9. Generally, the plan
considers only siting and level of treatment con-
siderations for the basin; population estimates
(flow requirements) are projected only to 1977.
Advanced methods of wastewater treatment will be
utilized for wastes entering the Dillon Reservoir
watershed, and for most of the lower Blue River
(except for the area below Green Mountain Reservoir),
Interceptor sewers as shown for Alternative 6 on
Figure 12 are proposed in the plan.
SLUDGE DISPOSAL
The plan recommends that the current method of
landfill ing sludge from wastewater treatment plants
be continued.
WASTE LOAD ALLOCATIONS
The treatment facilities proposed in the Plan must
conform to the waste load allocations which have
been established for Dillon Reservoir and the Blue
River. The important parts of this allocation plan
are included in this EIS as Appendix "B". In ad-
dition, the plan states that "residual chlorine
levels in the effluent at the point of discharge
should be less than 0.006 mg/1 for the wastewater
treatment plant at the confluence of the Blue River
and Dillon Reservoir and the plants discharging
directly to the lower Blue River".
WASTEWATER RECLAMATION BOARD
The Plan recommends that a centralized body respon-
sible for close coordination of wastewater treatment
efforts in the basin be formed. The plan recommends
that such a board be formed within 120 days following
final approval of this plan by EPA. The Board would
include representatives from each entity responsible
for wastewater treatment in the basin, and would be
responsible for the operation, maintenance, and moni-
toring of wastewater treatment facilities,
PRIORITIES
The Plan proposes that its recommended structural
strategy be implemented in an orderly manner.
Some of the items mentioned in this priority list
have already been accomplished, or are in the detailed
planning stages.
ADDITIONAL RECOMMENDATIONS: IMPLEMENTATION
The Plan correctly states that much of its implementa-
tion will be accomplished through the provisions of
the NPDES permit program, as administered by the
81
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State of Colorado. Revision of the plan will be
accomplished during the 208 Planning now underway,
and through the provisions of the State's Continu-
ing Planning Process.
The Plan recommends that all treatment plant op-
erators be certified; that monitoring of treatment
plant effluents, and stream and reservoir water
quality, be carried out; and that progress reports
regarding the implementation of the plan be made
to the Colorado Water Quality Control Commission
at regular intervals.
Although the plan recommends the construction of
several wastewater treatment facilities in the basin,
it does not commit the Federal government, or any-
body else, to the actual construction of anything.
Future requests to EPA for the Federal financing
of new treatment plants in the basin will be con-
sidered through the facilities planning process.
Detailed assessments of the environmental effects
of these proposals will be made at that time.
If necessary, additional impact statement(s) may
be required.
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V
Environmental Impacts
GENERAL
This chapter will assess both the beneficial and
adverse environmental effects of implementing the
proposed Water Quality Management Plan for the Blue
River Basin. The discussion will address the pri-
mary and secondary effects of the plan. Adverse
environmental impacts which cannot be avoided will
be highlighted in the following chapter. For ad-
verse environmental Impacts, possible mitigating
measures will be discussed.
WATER
A. Water Quality
Any of the proposed structural alternatives would
result in short-term water quality improvements
to the Blue River, Dillon'Reservoir, the Snake
River, Tenmile Creek, and Green Mountain Reservoir.
The main resons for this are:
1} The Plan calls for the phasing out of the many
small, poorly operated, "package plants" In the
basin. Some of these facilities (e.g., Key West
Farms; Keystone) have already been phased out of
operation.
2) The Plan calls for the upgrading and expansion
of existing facilities to meet the high standards
of wastewater treatment required for compliance
with the Waste Load Allocation Plan.
Direct improvements in water quality which will re-
sult from constructing improved wastewater treat-
ment plants will include reduced levels of BOD,
suspended solids, nutrients (primarily phosphorous),
and bacteria, in the plants' effluents.
The long-term effects on water quality, especially
in Dillon Reservoir, are more uncertain. The con-
tinued discharge of treated wastewaters to the arms
of the reservoir will be at the risk of possible
long-term eutrophication effects, including algae
blooms. The waste load allocations are designed
to minimize the risks, and can be considered a
mitigating measure. Monitoring of the water quality
in the reservoir, and the implementation of future
plans for improving water quality from treatment
plants are further mitigating measures.
If treatment plants and sewers are constructed
In accordance with the provisions of this plan,
unavoidable adverse impacts associated with con-
struction activities can be expected. Siltation
into nearby receiving waters, with resultant pos-
sible effects on fish spawning, will be the most
probable effect. These Impacts will be assessed
in detail as facility plans for new treatment works
or sewers are prepared.
It is possible that adverse effects on water quality
could result if treatment plants 1n the basin are
poorly operated, or suffer mechanical failures.
However, the plan recommends that operators of these
plants be highly trained, and certified. Back-up
systems to avoid or reduce the Impacts of mechani-
cal failures can be designed into new treatment
plants.
85
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Unless careful consideration is given to climatic
factors during plant design, the harsh climate of
the basin could create problems in the plants' phos-
phorus removal efficiencies, thus adding to the
eutrophication potential of Dillon and Green
Mountain Reservoirs.
Continuation of present sludge disposal practices
in the basin could result in adverse water quality
impacts if sludge leachate from the landfill reaches
groundwater. To date, no evidence is available that
would demonstrate that problems exist with the sys-
tem. Implementation of the plan's recommendation
for a centralized sludge disposal facility for the
basin would reduce the long-term impacts on water
quality.
Continual review and updating of the waste load al-
locations and provisions of NPDES .permits will, al-
ong with effluent monitoring, assure that wastewaters
discharged into the basin are in compliance with ap-
plicable regulations.
Implementation of the plan will result in a direct,
long-term benefit to citizens of the Denver area,
by eliminating the discharge of inadequately-treated
municipal wastewaters in Dillon Reservoir.
Secondary impacts on water quality which could result
from the implementation of the proposed plan must be
examined with care. Most important are the time
frames of the plan itself, and the waste load allo-
cations. Considering both of these parts of the
'plan, a discrepancy is apparent. The proposed struc-
tural measures of the plan involve planning for waste-
water flows only to the year 1977. However, the
wasteload allocations were based on population pro-
jections to 1990. For the purposes of this EIS,
the discussion of specific secondary impacts on water
quality will be limited to the 1977 planning period
used in proposing structural solutions to the water
quality problems in the basin. However, generali-
zations of secondary impacts resulting from the con-
tinued implementation of the waste load allocations
will also be attempted.
Central to a discussion of secondary impacts which
could result from the implementation of the plan
are population projections (Chapter 2). Using the
figures which were developed during the preparation
of the waste load allocations (50,000 in 1980;
90,000 in 1990 for the basin above Dillon Reservoir),
domestic wastewater flows into Dillon Reservoir
will reach 5.75 MGD in 1980, and 10.35 MGD by 1990.
Assuming the use of the best available technology
for wastewater treatment in the areas of disinfec-
tion and phosphorous removal, it may be technically
feasible to comply with the waste load allocations.
On the other hand, the technology available for the
removal of phosphorus may be the limiting factor.
Unless more sophisticated treatment, such as rev-
erse osmosis, is provided, or some means are pro-
vided to divert wastewaters out of the Upper Blue
River Basin, then the phosphorus limitations will
tend to limit growth in the basin.
However, it does not necessarily follow that the
pristine quality of waters in Dillon Reservoir and
Green Mountain Reservoirs will be preserved. The
primary reason for this statement is this: while
the water quality management. RlaJI (and subsequent
plans) for controlling the discharge of sewagp
effluents mav be the
ava
trols in th* hasin for rnnt.rn
lable, exiting
l ing non-point.
of pollutio" * nnt nf a comparable quality. There-
fore, as population in the upper basin increases to
levels predicted in Chapter 2, there will be con-
86
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tinued, and possibly accellerated, adverse impacts
on water quality -- from non-point sources such as
septic tanks and urban runoff unless plans are
developed, implemented, and enforced, to control
these problems. In Summit County such pollutants
include, but are not limited to, bacteria and nu-
trients from septic tank effluents; salts and sus-
pended solids from road salting and road construc-
tion activities; oils, greases, and solids from gen-
eral urban runoff; and even the possibility that as-
bestos could enter the hydrologic system as parti-
cles settle out of the atmosphere from automobile
and truck brakes.
If one assumes that the proposed plan (with flow
projections to 1977 only) will induce, rather than
accommodate population growth in the service areas
of the treatment plants, then it follows that some
of the secondary effects on water quality discus-
sed above will occur. This question of induce or
accommodate will probably never be answered to ever.y-
ones satisfaction. However, it is the responsibility
of EPA to consider these possibilities during the
process of approving the plan, and to insure that
planning for wastewater treatment facilities in the
basin is in concert with other, ongoing, planning
efforts in the area. Further, it is EPA's respon-
sibility to identify mitigating measures which can
be realistically implemented to reduce the impacts.
The following mitigating measures are available:
1) As discussed in Chapter 2, Summit County is de-
veloping a comrehensive land use plan. This plan
will contain recommendations for land use controls
which are central to minimizing secondary impacts '
on water quality, especially from non-point sources.
2) The Northwest Colorado Council of Government's
208 Plan (Chapter 2) will contain specific plans
for controlling point and non-point sources of pol-
lution. Land use controls as they may improve wa-
ter quality, will be developed in the plan. Before
EPA approves this plan, additional environmental
assessments of the secondary impacts will be con-
ducted .
3) Future plans developed by the State of Colorado's
continuing planning process will address the primary
and secondary impacts of revisions or modifications to
the plan now under consideration.
4) Facility plans for new wastewater facilities
(including interceptor sewers) will address the
secondary environmental effects in an environmen-
tal assessment or EIS.
It can be argued that excess capacity is being de-
signed into the wastewater treatment system for
the basin, as indicated by the flow projections
to 1977. As mentioned earlier, the plan calls for
facilities with a total capacity of 6.0 M6D to serve
the upper basin (including the Dillon-Silverthorne
area, some of which is not really "upper basin").
Remember two things: first, the 6.0 MGD figure will
accommodate peak populations - not just permanent
full-time residents; second, this point is some-
what moot it takes several years to plan, design,
and construct new or expanded wastewater treatment
facilities. At the present time (January, 1976),
planning for new facilities is underway only at
the Frisco plant, Silverthorne, and East Dillon
sites. It is most likely that further funding
requests for detailed design of these facilities
will be made to EPA and the State of Colorado,
87
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thus subjecting the plans to further environmental
analyses. When these plans are received by EPA,
special attention will be given to the secondary
environmental effects, as well as making sure that
the facilities' capacities will not be designed to
excess. As information is developed from the coun-
ty's comprehensive plan and the 208 Plan, this
material will also be considered.
B. Water Quantity
The direct effects of implementing the proposed plan
on water quantity are expected to be minimal. The
proposed plan involves only a minimum of regionali-
zation. Therefore, there will be little disruption
of the existing system of wastewater discharge. The
only effects on water quantity would be a very slight
reduction in streamflows following the phasing out
of the small "package plants" as recommended in the
plan. However, the total flows from these facili-
ties probably do not exceed 10,000 gallons per day.
No interference with adjudicated water rights is
expected from the implementation of the plan.
AIR QUALITY
Few direct effects on air quality in the basin can
be attributed to the implementation of the plan.
As new, expanded, or modified treatment facilities
are constructed, reductions in odor problems can be
expected as new technologies are applied. Some di-
rect air quality degradation can be expected during
construction. These impacts will be assessed in
detail as individual facilities plans are developed.
If population in the basin increases as projected in
Chapter 2, additional air quality degradation can
be expected. This would be in the form of emissions
from increased vehicular traffic, and fireplaces.
Uncertainties in the final design capacities of pos-
sible wastewater facilities make it impossible to
attribute these increases to the Water Quality Man-
agement Plan at this time.
The air quality study now being conducted by
Ambient Analysis, Inc., can be considered a miti-
gating measure, since the County intends to in-
corporate the results into their Comprehensive Plan.
BIOLOGICAL RESOURCES
The primary impact on biological resources from the
implementation of the plan would be on the fisheries
resources, especially in Dillon Reservoir. Chlorine
concentrations as recommended in the plan may not
be sufficient to protect valuable spawning areas
used by the Brown Trout. As a mitigating measure,
EPA's review of future facility plans will thoroughly
consider the impact of continued chlorination on the
fisheries resources of the area. In addition, the
continuing review and revision of the NPDES permit
provisions will be made with special attention to
the chlorination problem.
Some direct impacts on the biological resources of
the basin can be expected during construction and
expansion of the wastewater treatment facilities.
However, the selected plan involves a minimal amount
of physical disruption to the system, and measures
will be taken as needed to reduce these impacts.
As is the case with water quality and air quality,
some secondary effects on biota can be expected
as the plan's features are implemented. Increased
urbanization in the county will result in a loss
of habitat, and some species will undoubdtedly be
reduced in numbers, or displaced entirely. Pressures
88
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on the National Forest lands in the county will also
be increased along with urbanization, with similar
effects. Future Unit Plans of the Forest Service
will address these impacts in more detail.
LAND USE
Direct effects of the Plan on land use in the county
are expected to be minimal, since few changes from
the present configuration of treatment facilities
are proposed. Lands previously occupied by small
treatment plants will become available for other
uses, while few new lands will be acquired. Land
disturbance from sewer construction is expected to
be slight, since many of the sewers required for im-
plementation of the plan have already been construc-
ted. Individual facility plans, the county compre-
hensive plan, and the 208 Plan will consider these
problems in detail.
The secondary effects on land use from Implementing
this plan are Impossible to predict at this time.
The county's comprehensive plan is being developed
with consideration of the need for providing waste-
water treatment facilities, and the county is using
the "interim" water quality management plan in their
land use planning work. It is expected, then, that
water quality management planning efforts are pro-
ceding In concert with land use planning efforts
in the county. Additional analysis of this will be
available from the 208 Plan.
SOCIO-ECONOMIC IMPACTS
Full implementation of the plan could result in
some socio-economic impacts in the basin. Contin-
ued construction of treatment facilities would
stimulate the construction .industry, and would be
a beneficial impact. Negative impacts could eventu-
ally result if technological limitations of treatment
plants result in "using up" the waste load alloca-
tions, thus restraining growth.
Since most facilities called for in the plan are
already located at the sites, no displacement of
persons would be expected.
ADDITIONAL ENVIRONMENTAL IMPACTS
As indicated by the discussion of impacts on water
quality and quantity, air quality, biological re-
sources, and land use, the rather vague nature of
the proposed plan makes it difficult, if not impos-
sible, to quantify environmental impacts. As the
plan is implemented, it is very conceivable that
direct (primary) and/or indirect (secondary) impacts
on additional areas Identified in Chapter 2 could
occur. Since the plan itself offers few specifics
regarding the actual facilities which may be in-
stalled, we can offer little at this time in the
way of a detailed environmental assessment. This
process will be expanded upon during the later de-
velopment of facility plans and the 208 Plan.
89
-------
VI
Unavoidable Adverse Impacts
Adverse impacts discussed in Chapter V which cannot
be avoided include:
The direct discharge to Dillon Reservoir arms
will result in the continued degradation of
these water bodies. The degree of degradation
can only be ascertained by continuous monitor-
ing and surveillance of treatment plants and
receiving waters.
Standard chlorination processes will adversely
affect the reproductive process of certain
aquatic species.
Increased volumes of sludge generated by the
proposed advanced waste treatment facilities
will add to disposal problems. It may not be
feasible to recycle the chemical sludges thereby
increasing operating costs. Land application
of chemical sludges will damage plant life.
All proposed alternatives will result in the
continued degradation of Green Mountain Reser-
voir unless ultimate growth limitations are
imposed.
Adverse secondary effects could involve short-
term water quality degradation due to sewerage
construction activities and operational failures.
Long-term degradation will result from storm-
water run-off, septic tank leaching and other
non-point sources of water pollution.
Full implementation of the plan (eventual con-
struction) will result in short-term adverse
effects from construction on water quality,
noise, and biological resources.
91
-------
VII
Relationship Between Local Short -
Term Uses Versus Long-Term
Productivity
The long-term productivity of the Blue River Basin
and Summit County 1s dependent largely upon the
maintenance of a high-quality living environment,
which in turn brings social and economic gain to
the area through use of the recreational areas which
are available. If the proposed Water Quality Manage-
ment Plan 1s Implemented, short-term environmental
gains (e.g., Improvements to water quality In Dillon
Reservoir) may result. Over the long-term* however,
the continued provision of utility services such as
these could reduce the productivity of the area,
if Increased populations are accomodated without
sufficient consideration to the environmental car-
rying capacity of the basin.
The proposed practice of continuing to discharge
wastewaters Into Dillon reservoir may Improve water
quality over the short term, but 1f increases occur
in levels of non-point sources of water pollution,
the long-term threat of eutrophication remains.
The proposed plan does not foreclose options for
treating domestic wastes. As noted previously, the
plan 1s quite flexible, and 1s subject to regular
revisions, as part of the "continuing planning pro-
cess." In addition, the 208 Plan which is now in
the early stages may show that modifications are
needed in order to best protect the resources of
the basin over the long term.
It has been EpA's determination that the implemen-
tation and enforcement of the waste load allocations
to Dillon Reservoir is necessary for the protection
of water quality. To some extent, this decision
requires either l)the construction of advanced waste-
water treatment works, 2)the elimination of sewage
discharges into Dillon Reservoir, or 3)l1mitations
on urbanization in the watershed. The action recom-
mended in the proposed plan (advanced treatment)
would probably disrupt the existing environmental
features of the area less than the others.
93
-------
VIM
Irreversible and Irretrievable
Commitments of Resources
Complete implementation of the proposed plan would
involve the following irreversible and irretrieva-
ble commitments of resources:
1. Eutrophication of a water body is a natural pro-
cess. Construction of all the facilities called for
in the plan would result in the continued discharge
of nutrients to Dillon and Green Mountain Reservoirs,
notwithstanding the waste load allocations. The
process of eutrophication, although probably post-
poned by implementation of the plan, is probably
inevitable and irreversible.
2. Full implementation of the plan would require
materials for construction of wastewater treatment
plants, sewers, and sludge disposal equipment.
Exact amounts of materials required are not avail-
able at this time.
3. Construction and operation of any of the facili-
ties called for in the plan would require energy,
which would then not be available for other uses.
4. Lands and rights-of-way for facilities called
for in the plan would be committed to those uses.
95
-------
Bibliography
97
-------
Bergendahl, Max H., 1963, Geology of the northern
part of the Tenmile Range, Summit County, Colo-
rado. U.S.G.S. Bulletin 1162-D.
Bermingham, John R., 1974. 1974 Land Use Legislation.
Denver Law Journal, V. 51, No. 4.
Denver Board of Water Commissioners, 1974. 1974 Wa-
ter Quality Report.
Environmental Protection Agency, 1973. Dillon Res-
ervoir - Blue River Study. (Surveillance and
Analysis Division - Technical Investigations
Branch.
, 1973. Water Quality Management Analy-
sis of Summit County, Colorado.
Hoi ben, Brent N., and W.E. Marlatt, 1974. Air Pol-
lution Potential analysis of Summit County.
Submitted to the Summit County Planners Office.
Singewald, Quentin D., 1951. Geology and Ore Deposits
of the Upper Blue River Area, Summit County,
Colorado. U.S.G.S. Bulletin 970.
U.S. D.A., Soil Conservation Service, 1972. Table of
Characteristics for Soil Association Tables.
Voegeli, Paul T., 1964. Groundwater Resources of
North Park and Middle Park, Colorado --
A Reconnaissance.
98
-------
Appendices
99
-------
APPENDIX "A"
-------
COLORADO DEPARTMENT OF HEALTH
Water Quality Control Commission
4210 East llth Avenue
Denver, Colorado 80220
Adopted: January 15, Wt
Effective: June 19, \97>t
WATER QUALITY STANDARDS FOR COLORADO
AUTHORITY
These standards are promulgated pursuant to section 66-28-202(6) and
section 66-28-20't C.R.S. 1963, as amended.
PURPOSE
These standards are the foundation for the classification of the
waters of the State of Colorado, as defined In the Water Quality Control
Act of 1973, Intended to Implement the act, to maintain and to enhance the
quality of the state's waters for public water supplies, for protection
and propagation of wildlife and aquatic life, and for domestic, agri-
cultural, Industrial, recreational and other beneficial uses. They are
further Intended to be consistent with the goals and policies of the
Federal Water Pollution Control Act Amendments of 1972, which are stated
'> section 101 thereof. These standards shall be construed In a manner
consistent with these purposes.
The division shall review stream standards not less than once every
three years and report Its findings to the commission.
Sampling for the purpose of determining quality of state waters shall
not be done In areas Immediately adjacent to outfalls.
The area or volume of a stream designated by the division within
"""ch effluent shall become thoroughly mixed with the waters of the stream.
The total area or volume of a stream designated as a mixing zone shall
" limited to that area or volume which will not Interfere with biological
communities or populations of Important species to a degree which Is damag-
'"9 to the ecosystem and which will not cause substantial damage to other
""flclal uses.
A continuous water route which joins segments of a stream, reservoir
r lake above and below a mixing zone without going through the mixing zone.
Water Quality Standards for Colorado
Adopted: January 15, 1971)
Effective: June 19. I971*
ZONE OF PASSAGE (continued)
The zone of passage shall have volume and area sufficient to allow
passage of freeswlmmlng and drifting organisms In a manner producing no
significant effects on their populations except during periods when there
Is no water In the stream, lake or reservoir, or except when flow or level
Is less than the minimum seven day low flow or level which Is expected to
occur once In ten years.
FLOW CRITERIA AND EXCEPTIONS
The water quality standards for a particular class of water shall
apply at at Imel, except during period, of time when lake or reservoir
water levels or streamflows are less than the minimum seven day low flow or
Tevel which Is expected to occur once In ten years. During such periods
ofl'met the ba"c water quality standards shall apply. Exceptions on
specific parameters may be allowed through discharge permits.
ANALYTICAL TESTING
Tests or analytical procedures to determine compliance with standards
shall, nso?ar as practicable and applicable be made In accordance with
the methods given In the latest edition of "S»^ar^Me^J°%'£"
Examination of Water and Waste Water" published by the *"T'«"^£"«
Health Association, or In accordance with tests or analytical procedures
which the commission finds to be at least equally satisfactory.
ANT I DEGRADATION STATEMENT
Waters of the state, whose quality exceeds the limits-
-------
Water Quality Standards for Colorado
Adopted: January 15, 1974
Effective: June 19, 197'
leters, nor do 20 percent of the total collform groups exceed 2000 gr°up
per 100 mllllllters during any 30-day period. In addition, the fecal
streptococcus count does not exceed an average of 20 per 100 ml III lit*'.
based upon an average of five consecutive samples within a 30-day perl" '
ill''
b. The dissolved oxygen concentration Is not less than 6 ""'
grams per IIter.
c. A pH rating of not more than 8.5 nor less than 6.5 units-
d. Temperature maintains a normal pattern of diurnal and **a\t
sonal fluctuations and does not change abruptly. No warming discharge,
permitted In the hypolimn Ion of lakes. Temperature Is not Increased *,
68° F. by any means other than natural means, or Is temperature incre* ^
In streams and In the epllimn Ion of lakes or reservoirs more than 2°f"
any discharge.
e. Wastes of other than natural origin do not cause the t»r
bldlty of the water to be Increased by more than ten Jackson Turbidity
Units or Its equivalent.
(3) Water In class A2 exhibits or Is to exhibit the following
characteristics:
- 3 -
- 4 -
A - 2
-------
Water Quality Standards for Colorado
Adopted: January 15, 197*1
Effective: June 19, 197*
a. Bacteriological concentrations which do not exceed a geometric
"lean of 200 fecal col I form groups per 100 mllliliters nor 1000 total coil-
form groups per 100 mllliliters based on a minimum of not less than five
samples obtained during separate 24-hour periods for any 30-day period, nor
do 10 percent of the fecal coliform groups exceed 400 groups per 100 mil II-
"ters, nor do 20 percent of the total coliform groups exceed 2000 groups
Per 100 mi Hi liters during any 30-day period. In addition, the fecal
streptococcus count does not exceed an average of 20 per 100 mill!liters
based upon an average of five consecutive samples within a 30-day period.
b. The dissolved oxygen concentration is not less than 5 milli-
grams per Iiter.
c. A pH rating of not more than 8.5 nor less than 6.5 units.
d. Temperature maintains a normal pattern of diurnal and sea-
sonal fluctuations and does not change abruptly. No warming discharge Is
Permitted in the hypolimnion of lakes or reservoirs. Temperature is not
increased above 90° F. by any means other than natural means, or Is tem-
Perature Increased by discharges in streams more than 5° F., and in the
'Pilimnion of lakes or reservoirs more than 3° F-
e. Wastes of other than natural origin do not cause the tur-
bidity of the water to be increased by more than ten Jackson Units or its
e[lulvalent.
WATER QUALITY STANDARDS FOR CLASS BI OR B2
(1) State waters designated class BI or B2 are waters suitable or to
b«come suitable for all purposes for which raw water Is customarily used,
e*cept primary contact recreation, such as swimming and water skiing.
(2) Water In class BI exhibits or Is to exhibit the following
ch«racterlstlcs:
a. Bacteriological concentrations do not exceed a geometric
mean of 10,000 total coliform groups or 1000 fecal coliform groups per 100
"""Ulters based on a minimum of not less than five samples obtained during
*«Parate 24-hour periods for any 30-day period, nor do 10 percent of the
'*«! coliform samples exce|ed 2000 groups per 100 mllliliters during any
J°-day period.
b. The dissolved oxygen concentration is not less than 6 milli-
grams per liter.
c. A pH rating of not more than 9.0 nor less than 6.0 units.
Water Quality Standards for Colorado
Adopted: January 15, 1974
Effective: June 19, 1974
d. Temperature maintains a normal pattern of diurnal and sea-
sonal fluctuations and does not change abruptly. No warming discharge
Is permitted In the hypollmnfon of lakes. Temperature Is not increased
above 68° F. by any means other than natural means, nor is temperature
Increased in streams and In the eplllmnlon of lakes or reservoirs more
than 2° F. by any discharge.
e. Wastes of other than natural origin does not cause the tur-
bidity of the water to be Increased by more than ten Jackson Units or its
equivalent.
(3) Water in class 63 exhibits or is to exhibit the following
characteristics:
a. Bacteriological concentrations do not exceed a geometric
mean of 10,000 total coliform groups or 1000 fecal coliform groups per 100
milllllters based on a minimum of not less than five samples obtained during
separate 24-hour periods for any 30-day period, nor do 10 percent of the
fecal coliform samples exceed 2000 per 100 mllliliters during any 30-day
period.
b. The dissolved oxygen concentration Is not less than 5 milli-
grams per liter.
c. A pH rating of not less than 6.0 nor more than 9.0.
d. Temperature maintains a normal pattern of diurnal and sea-
sonal fluctuations and does not change abruptly. No warming discharge Is
permitted In the hypolimnion of lakes or reservoirs. Temperature is not
Increased above 90° F. by any means other than natural means, or Is tem-
perature Increased by discharges more than 5° F. in streams and more than
3° F. In the eplllmnlon of lakes or reservoirs.
e. Wastes of other than natural origin does not cause the tur-
bidity of the water to be Increased by more than ten Jackson Units or its
equivalent.
- 6 -
- 5 -
A - 3
-------
TERMS AND DEFINITIONS
AS PRESENTED BY
THE WATER QUALITY CONTROL COMMISSION
BIOCHEMICAL OXYGEN DEMAND - A measure of the amount of oxygen necessary
to satisfy the biochemical oxidation requirements of pollution in a
sample that is maintained at a temperature of 20° Centigrade for a
period of five days.
BIOCIDE - A toxic, chemical substance or mixture intended to abate or
destroy noxious forms of life, such as vermin, insects, viruses and
fungi harmful In agriculture, fisheries and forestry.
CLASSIFICATION - The application of a standard or standards to a segment
or segments of the waters of the state.
CPU FORM GROUP ORGANISMS (TOTAL COL I FORM GROUPS) - The col I form group
includes all of the aerobic and facultative anaerobic, Gram-negative,
non-spore forming, rod shaped bacteria that ferment lactose broth
with gas formation within 1(8 hours at 35° Centigrade.
CONDUCTIVITY - A measure of the ability of water to conduct an electric
current, which may be used for approximating the salinity In water.
CONTROLLABLE SOURCES - A source of waste discharge that can be controlled
by physical means.
DISINFECTION - A method of reducing the organisms pathogenic to man.
DISSOLVED OXYGEN - A measure of the amount of free oxygen (oxygen which
Is not chemically combined with other substances) available in water
to oxidize oxygen demanding materials.
EPILIMNION - In a thermally stratified lake, the layer of water that
extends from the surface to the thermocline.
EUTROPHICATION - The process of a lake becoming rich in dissolved
nutrients thereby enhancing the growth of aquatic plants leading
to possible seasonal oxygen deficiencies and accelerating the rate
of lake aging.
FECAL COL I FORM ORGANISMS - That portion of the coliform group which Is
present In the Intestinal tract of warm-blooded animals. It
generally Includes organisms which are capable of producing gas
from lactose broth In a suitable culture medium within 21) hours
at Vt.5° ± 0.5° Centigrade.
HYPOLIMNION - The region below thermal stratification in a lake or
reservoir.
MF_ - Refers to the membrane filter technique of water analysis. This
technique involves the passing of a certain volume of water through
a cellulose ester filter which is then impregnated with a food product
for the bacteria that are retained on the surface of the filter.
- 7 -
MPN - An abbreviation of "Most Probable Number" - a test of bacter at
- density derived from multiple tube fermentation techniques. t s
expressed as a number of organisms per hundred mllliliters. It is
a number most likely to occur, In statistical theory, under the
given circumstances or conditions of the test.
MILL I EQUIVALENT PER LITER - A unit for expressing the concentration of
- chemical constituents In terms of Interreact Ing values of electrl
cally charged particles or ions in solution. One ml 11 lequlva ent
per liter of a positively charged Ion will react with one mllll-
equivalent per liter of a negatively charged ion.
MILLIGRAMS PER LITER - Also referred to as "parts per million.1'- This Is
- a unit for expressing the concentration of any substance by *«'9"'
usually as grams of substance per million grams of solut on. Since
a liter of water weighs one kilogram, one milligram per liter is
equivalent to one part per million.
HILLILITER - One-thousandth of a liter. One liter is equal to 1.06 quarts-
NATIONAL BUREAU OF STANDARDS HANDBOOK 69. LATEST EDITION - A
- book published by the U. S. Department of Commerce, National Burea
of Standards. It contains recommendations as to the maximum per
mlsslble concentrations of radio nuclldes in the human body, air,
and water.
NATURAL CAUSES - (As applied to temperature fluctuation standards) -
- Temperature fluctuations due to effluents from domestic sewage tr
ment plants and Identifiable Irrigation return flows shall be con
ered as originating from natural causes.
pH - The PH value Indicates the relative intensity of acidity o
*- of water, with the neutral point at pH 7.0. Values lower than 7.°
Indicate the presence of acids; above 7-0, the presence of alkali
PRIMARY CONTACT RECREATION - Raw surface waters In which the human body
- may be completely submerged and there Is prolonged and intimate
contact Involving considerable risk of Ingesting waters n suff '
clent quantities to pose a significant health hazard. Although »
water may be Ingested accidentally, It Is not Intended for «» ",
potable water supply unless acceptable treatment s app led. in
waters may be used for swimming, water skiing, skin diving and ot
similar activities.
SECONDARY CONTACT RECREATION - Raw surface water where the human body ^
- come In direct contact with the water but normal y not to the po r
of complete submergence and there Is little likelihood tha the ^
will be Ingested. This water may be used for fishing, boating an
other similar activities.
SODIUM ADSORPTION RATIO - An index of hazard to physical condition of
soil due to sodium In Irrigation water.
- 8 -
-
-------
STANDARD METHODS FOR THE EXAMINATION OF WATER AND WASTE WATER. LATEST
EDITION - A publication prepared jointly by the American Public Health
Association, American Water Works Association, and the Water Pol-
lution Control Federation, accepted by Federal, State, and local
authorities in the field of water pollution control as the authority
for analytical procedures to be utilized in the examination or
analysis of waters and waste waters.
STANDARDS - An official limiting value used to determine the quality of
water for a classified use as established by the Water Quality
Control Commission.
THERHOCLINE - In thermally stratified lakes, the layer below the eplllmnion.
It Is the stratum In which there Is a rapid rate of decrease In temper-
ature with depth; a minimum of one degree Centigrade per meter In depth.
IPX 1C MATERIAL - Materials which are harmful to human, plant, animal, and
aquatic life.
TURBIDITY - A measure of the clarify and the light penetration of water as
affected by suspended and colloidal matter.
Adopted: March 19, 197^
Effective: June 19, I97<4
CLASSIFICATION OF
INTERSTATE AND INTRA5TATE STREAMS
IN COLORADO BY RIVER BASINS
AUTHORITY: Section 66-28-202(a) and Section 66-28-203 C.R.S. 1963,
as amended.
GENERAL PROVISIONS:
I. Basic Standards will apply to all waters of the state, as
defined in the Water Quality Control Act, whether classified or not.
2. The classification of waters shall not be construed as an
action to supplant or Interfere with decreed uses of the water.
Nothing herein shall be construed to require the delivery of water
from one basin to another or from one state to another or to affect
the provisions of any interstate compact or U. S. Supreme Court
Decision.
3- Owners (municipalities, irrigation companies and industries)
of specific bodies of water may utilize the waters as desired provided
that the water quality standards set for that body of water are
maintained.
- 9 -
A - 5
- 10 -
-------
Adopted: March 19, 1971*
Effective: June 19, 197*»
WATER QUALITY STANDARDS SUMMARY
STANDARD
Settleable Sol ids
Floating Sol i ds
Taste, Odor, Color
Toxic Materials
- Oi 1 and Grease
Radioactive Material
Fecal Coliform Bacteria
Turbidi ty
Dissolved Oxygen
">j
PH
Temperature
Fecal Streptococcus
CLASS
Al
Free From
Free From
Free From
Free From
Cause a f i 1m or
other discoloration
Drinking Water
Standards
Geometric Mean of
< 200/1 00ml from five
samples in 30-day per
No increase of more
than 10 J.T.U.
6 mg/1 minimum
6.5 - 8.5
Maximum 68°F.
Maximum Change 2°F.
Monthly average of
<20/ 100ml from five
samples in 30-day per.
A2
Free From
Free From
Free From
Free From
Cause a f i 1m or
other discoloration
Drinking Water
Standards
Geometric Mean of
< 200/1 00ml from five
samples in 30-day per.
No increase of more
than 10 J.T.U.
5 mg/1 minimum
6.5 - 8.5
Maximum 90° F .
Maximum Change:
Streams - 5°F.
Lakes - 3°F.
Monthly average of
<20/ 100ml from five
samples in 30-day per.
Bl
Free From
Free From
Free From
Free From
Cause a f i 1m or
other discoloration
Drinking Water
Standards
Geometric Mean of
< 1000/1 00ml from five
samples in 30-day per.
No increase of more
than 10 J.T.U.
6 mg/1 minimum
6.0 - 9.0
Maximum 68°F.
Maximum Change 2°F.
B2
Free From
Free From
Free From
Free From
Cause a film or
other discoloration
Drinking Water
Standards
Geometric Mean of
< 1000/1 00ml from five
samples in 30-day per.
No increase of more
than 10 J.T.U.
5 mg/1 minimum
6.0 - 9.0
Maximum 90°F.
Maximum Change:
Streams - 5°F.
Lakes - 3°F.
-------
APPENDIX "B"
-------
The Interactions of the total environment and the trophic (nutritional
conditions) of a lake are many and extremely complex. Figure 9 1s an at-
tempt to simplify and graphically Illustrate the major factors affecting the
nature of a water Impoundment. Under wilderness conditions mineral salts
brought in from weathered soil, plus degradable organic matter of terres-
trial and aquatic origin, furnish the nutrients which support the normal
aquatic food chain. Generally, the amount of mineral and organic matter 1s
the limiting factor in the abundance of aquatic life. Whenever such factor
1s limiting, the system is nutrient sensitive and can be expected to react
quickly to the addition of fertilizer compounds at a low energy level; or to
change in population characteristics 1f the compounds enter at a high energy
'evel (17). Significant changes in the addition of nutrients causes acceler-
ated cycles of growth and death of aquatic organisms. The dead bodies of the
organisms then exert a significant oxygen demand resulting in depressed dis-
solved oxygen levels and cause further effects on other forms of aquatic
Hfe such as fish. Upon blodegradation of the dead material, the mineral
and organic compounds become available again for the fertilization of
other aquatic organisms. A self perpetuating cycle occurs unless the nu-
trient compounds are physically removed from the body of water.
In a reservoir or lake, the mineral and organic compounds may be rele-
Sated to a particular location within the body of water. This is especially
true if the system 1s thermally stratified. In a stratified lake or reser-
v°1r. vertical motion and mixing is inhibited by different water densities
at different elevations in the body of water. As air temperature, Insola-
tion and Inflow temperatures change throughout the year, this stratification
-34-
B- 1
<
u.
o
a
z
C
a
o>
-35-
-------
pattern changes causing significant mixing to occur within a relatively
short period of time. This mixing aids in making nutrient compounds avail-
able for phytoplankton to feed upon and flourish (16).
In addition to the degradation of water quality from the process of
eutrophication, the nutrient substances present in sewage effluents fre-
quently lead to the production of sudden algae "blooms" or periods of ac-
celerated growth causing extreme turbidity. Death and decomposition of the
algae then produce odors and floating mats or globs of decomposing organic
matter. Such matter is extremely disagreeable to boatmen, fishermen and
other users. Another effect of eutrophication is a change in the type and
species of fauna inhibiting an eutrophied lake. The fish population has been
observed to change from game fish such as trout and whitefish to nongame
species such as carp. Degradation of quality of a domestic or industrial
water supply increases the treatment effort required to reach an acceptable
quality for desired uses.
Dillon Reservoir has recognized characteristics which make it very
susceptible to accelerated eutrophication. The reservoir is deep with a
well defined thermal stratification pattern as indicated by Figure 10. The
seasonal overturn should effect an adequate mixing of the reservoir contents.
The light penetration is good and insolation at an altitude of 9,000 feet
provides adequate energy for abundant photosynthetic action by phytoplankton.
Size, volume and inflow parameters to Dillon Reservoir indicate a detention
time in the reservoir on the order of one year. This exposes the entire con-
tents to a complete stratification cycle.
Green Mountain Reservoir is smaller than Dillon Reservoir with a higher
-36-
25
DILLON RESERVOIR
TEMPERATURE STRATIFICATION
DATA SOURCE:
U.S.8.S WATER RESOURCE DIVISION
COLORADO DISTRICT SURVEY OF 1970
225
B - 2
67 8 9 10 II 12 13
TEMPERATURE IN DEGREES CENTIGRADE
RGURE 10
-37-
17
-------
Inflow rate and a proportionately shorter detention time. It is shallower
but still is subject to stratification and mixing by annual overturning.
Insolation and light penetration conditions are assumed to be similar to
those in Dillon Reservoir.
Depletion of the dissolved oxygen resource in the streams of the Basin
require consideration also. Because of the relatively high velocities and
high reaeration coefficients, dissolved oxygen levels are not considered to
be a matter of great concern. What is of concern is the transportation of ox
ygen demanding material to the reservoirs. Because of the low temperatures
of the streams, normally less than 10°C, the biochemical oxygen demand is
satisfied relatively slowly, I.e., a low reaction rate coefficient. Due
to the relatively high velocities, the oxygen demand exerted by the discharge
of municipal wastes may not be satisfied before the stream discharges into a
quiescent body of water. Projected load, waste discharge dilution levels,
and reservoir response must be examined to evaluate the impact of this condi-
tion. Because of the Basin's use as a cold water fishery, ammonia toxicity
due to discharge of ammonia nitrogen must be considered also, however, this
problem is not expected to be serious.
C. Wastewater Treatment Facilities
A study and evaluation of water quality in streams and reservoirs re-
flect the amount and quality of waste put into the water resource. Table
7 shows a tabulation of all significant existing wastewater treatment plants
in operation in the Blue River Basin as of January 31, 1974. Not included
here are the numerous Individual treatment units of the septic tank classi-
fication.
TABLE 7
WASTEWATER TREATMENT FACILITY INVENTORY
January, 1974
Location
I. UPPER BLUE RIVER BASIN
A. Breckenridge Sanitation District Plants
1. Plant at Swan Mountain Road
2. Plant at Breckenridge (to be phased out
in 1974)
B. New Eldorado - Blue Valley Sanitation Dist.
C. Quandary Lodge Plant and Lagoon
D. Valley of the Blue Plant
E. McDill Placer Plant
II. SNAKE RIVER BASIN
A. Surnnit County Snake River Plant (Proposed
for construction 1n 1974)
B. East Dillon Water and Sanitation District
Plant
C. Key West Farms Plant
D. Keystone Base Plant
E. Arapahoe Basin Plant
Continued
-39-
Average Design
Capacity Population
Equivalents
20,000
20,000
2,000
250
200
100
100
10,000
500
200
500
200
-38-
B - 3
-------
TABLE 7
Continued
Location
Average Design
Capacity Population
Equivalents
III. TENMILE CREEK BASIN
A. Frisco Sanitation District
1. Existing Extended Aeration Plant
2. New plant to be put in operation in
B. Copper Mountain Water and Sanitation Dist.
C. Summit County Plant (Proposed to be con-
nected to Frisco Sanitation District in 1974)
IV. LOWER BLUE RIVER BASIN
A. Silverthorne Sanitation District Plant
(Secondary Treatment only at this time)
B. Buffalo Mountain Water and Sanitation Dis-
trict Plant - Abandoned and connected to
Silverthorne Facility
C. Town of Dillon Lagoon - Abandoned and con-
nected to Silverthorne Facility
D. Bureau of Reclamation Plant at Green Mountain
Reservoir
600
10,000
3,000
1,250
8,500
50
-40-
The average design flow rates expressed in population equivalents is
given. For the purposes of this plan, a population equivalent will gener-
ally be considered as an average flow of 100 gallons per capita per day.
The quantities given are those immediately projected or in use at this time.
Because of the rapidly changing conditions in the Basin, many of the waste-
water treatment plants are proposed to be altered or expanded in the near
future. Where these conditions might effect the evaluation of water qual-
ity impact, consideration has been made of the proposed changes.
Of the currently projected changes to occur in the near future, the
following are most significant.
Breckenridge Sanitation District
The plant at Sv/an Mountain Road 1s to be operational in early 1974
with average daily flow capacity of two million gallons. Discharge will
be to the Blue River approximately 1500 feet upstream from Dillon Reser-
voir.
The plant and interceptor sewer is designed for an ultinate service
area of the entire Upper Blue River Basin. Ultimate average daily plant
capacity could be 10-12 million gallons according to the service area
study for that facility.
Frisco Sanitation District
A plant with one million gallons per day average flow capacity will be'
come operational in 1974. Discharge will be to Miner's Creek approximately
1,000 feet upstream from Dillon Reservoir.
Silverthorne Sanitation District
A plant with secondary treatment capacity of 850,000 gallons per day
is operational at this time. An additional capacity of one million gal-
D -
-41-
-------
Ions per day 1s projected to be under construction in Spring of 1974.
Tertiary treatment facilities for an average daily flow of two million
gallons are constructed, but not operational as of January 31, 1974.
Summit County Snake River Plant
Plans and specifications are being prepared for a plant at the con-
fluence of the Snake River and Dillon Reservoir with an average daily
flow capacity of one million gallons with possible expansion to two
million gallons per day. Construction is projected to begin in 1974.
Data collected by the Denver Board of Water Commissioners shows that
the average influent quality of sewage to the major wastewater treatment
facilities is characterized by the following (1):
5-Day Biochemical Oxygen Demand * 250 mg/1
Phosphate as elemental Phosphorus = 7.5 mg/1
Total Kjeldahl Nitrogen 30 mg/1
This data may vary somewhat due to varying loads throughout the yearly cycle
°f population changes. These concentrations may increase 1n the future when
the quantity of dilution water presently introduced by excessive infiltration
and bleeding of domestic water lines during winter months 1s reduced by sys-
tem improvements.
Efficiency of treatment and resultant effluent quality parameters pre-
sently varies significantly throughout the year from facility to facility.
No significant data exists on the quality of effluent produced by the treat-
ment plants during the peak loading seasons. Let it suffice to say that many
Plants are overloaded with a comensurate decrease 1n treatment efficiency.
-42-
The Water Quality Management Analysis of Summit County prepared by EPA
represented typical waste loads with a sinusoidal relationship having a per-
iod of six months. The total waste load could be represented by the rela-
tively constant background loading, a loading by the average domestic waste
flow, and loading added by the peaking of wastewater flow during certain por-
tions of the year. This is graphically represented in Figure 11.
A mathematical model was used in the Water Quality Management Analysis
to evaluate the effect of this variable waste loading. It was found that
the overall effect was generally negligible when compared to the concentra-
tions resulting from background and average wastewater loading. The ampli-
tude of the variable waste loading was calculated to be 0.29 times the aver-
age waste flow assuming that the minimum loading was 55% of the peak waste
load. The EPA report indicated that this was reasonable when seasonal popu-
lation was compared to full time resident population. This could be further
verified by accurate wastewater flow and quality records if such existed.
(9
Z
5
g
T Amp
\
\
Amplitude
.-^.^-
Totol Loading
.\.-..._?._\ .... x
V / I Dom«*tic -^ V /
N/ Wastewoter Loading «»
I
Natural Background Loading
B - 5
6 mo.
TIME
FIGURE II
12 mo.
-43-
-------
CHAPTER IV
ANALYSIS OF MATER QUALITY VARIATION
A. Reservoir Response to Waste Loading
In this study and analysis of reservoir response to waste loading, popu-
lation projections and resulting wastewater flow were derived from populations
given in Chapter II, page 24. Figure 12 shows the relationship of full-
time and seasonal residents projected by the Therese Lucas study (12) and the
peak population projections given by EPA in the Water Quality Management Anal-
ysis (1). To determine an average wastewater loading throughout the six month
period shown in Figure 11 , an average peak population and loading was de-
rived by an average of the EPA and Therese Lucas seasonal projections repre-
sented by Curve A on Figure 12. Minimum population and loading was determined
by use of the full time residents projected by Therese Lucas' study and shown
as Curve B. Average population and loading can thus be determined for the
applicable design periods. Distribution among the sub-basins was done in the
same ratio as presented in the EPA report. Design population and wastewater
flow used in this analysis are detailed in Table 8.
It must be emphasized that the populations and wastewater flows given in
Table 8 are annual averages. They are used in the analysis because of the
importance of a yearly cycle of loading on the reservoir. The wastewater
y
treatment facilities must be designed to accommodate the daily, weekly, and
monthly fluctuation in wastewater quantity and composition.
-44-
190,000-
180,000-
170,000-
160,000-
150,000-
140,000-
130,000-
120,000-
o
I- 110,000-
<
a. 100,000-
o
a.
90,000-
80,000-
70,000-
60,000-
50,000-
40,000-
30,000-
20,000-
1970
t
I
EPA REPORT:
PEAK POPULATION
CURVE A
FIGURE 12
PROJECTED POPULATIONS
SUMMIT COUNTY
THERESE LUCAS^
SEASONAL PEAK POPULATION
THERESE LUCAS:
FULL-TIME RESIPENTS
CURVE B
P - 6
1980 1990
YEAR
-45-
2000
-------
TABLE 8
POPULATION AND
Basin
Upper Blue River Basin
Snake River Basin
Tenmile Creek Basin
Lower Blue River Basin
(a) Dillon Reservoir to Willow
Creek
(b) Willow Creek to Rock Creek
(c) Rock Creek to Green Mountain
Reservoir
WASTEWATER FLOW
Design
1977
11,528
5,589
6,987
9,781
699
349
Population
1992
42,973
9,647
11,401
18,417
4,385
977
Wastewater
Flow, MGD
1377
1.2
0.6
0.7
1.0
0.07
0.04
1992
4.0
1.0
1.1
1.8
0.4
0.09
The Environmental Protection Agency performed an Algal Growth Potential
Study in late 1973 to evaluate nutrient - phytoplankton growth relationships
in Dillon Reservoir (4). The work consisted of chemical and algal analyses
and a laboratory study of algal growth relationships under current nutrient
conditions and nutrient conditions associated with additional loading from
increased population in the Basin. Using water samples from the Blue River
Arm, Frisco Bay, and Main Body of the reservoir, various concentrations of
Phosphate and nitrate were added and the sample inoculated with the test
alga. Algal growth was then measured using a fluorometer to determine the
chlorophyll a. concentrations following each day of incubation.
-46-
The growth of such alga was expressed by the equation
X2 = XieK(Vtl)
where
then
X, = chlorophyll ^concentration at time t-|, mg/1
X2 = chlorophyll ^ concentration at time t2, mg/1
K = growth rate, days "^
t,, ty = time in units of days
K = In (x2/x-|)
The mean values of the observed growth rates for each water sample are
graphically shown on Figures 13 through 15. As a means of comparison and
expression, Figure 16 shows the relationship between algal growth rate as
expressed above and resulting changes in chlorophyll a_ concentrations. Chlor-
ophyll ^concentrations are assumed to be directly proportional to the amount
of phytoplankton biomass present at a given time. This 1s substantiated by
the use of the expression above to calculate growth rate from actual cell
counts under laboratory conditions of phosphorus limitation similar to those
in the study performed on Dillon Reservoir water samples (15).
As general trends, the results show that small increases 1n nutrient
concentrations above existing levels produce relatively large increases In
algal growth. By various combinations of phosphorus (P) and nitrogen (N)
concentrations, the study concluded that the test water in the laboratory
environment was phosphorus limiting and that additions of phosphorus to Dil-
lon Reservoir would result in increased algal growth. Additional loadings
-47-
- 7
-------
0.45-
LEGEND
N=0.44mg/l
N=0.39mg/l
N=0.35mg/l
N=0.34mg/l
0.40-
.0.35-
1
0.30-
0.25-
UJ
3
ffi
0.20-
0.45-
0.40-
0.15-
FIGURE ISA
LABORATORY STUDY
ALGAL GROWTH POTENTIAL
BLUE RIVER ARM WATER SAMPLE
Initial Phoiphorui Oonctntration = .018 mg/l
Initial Nitrogen Concentration « 0.34 mg/l
fCONTROL
0.10-
001
0.02
0.03
0.04
P,mg/l
-48-
o:os
0.06
0.35-
0.30-
rr
X
0.25-
or
ui
0.20-
0.15-
0.10-
LEGEND
P= 0.068 mg/l
P= 0.028 mg/l
A P = 0.023 mg/l
O- P = O.OI8mg/l
Initial Phosphorus Conctntrotion = 0.018 mg/1
Initial Nitrogen Concentration = 0.34 mg/l
3CONTROL
/ FIGURE 13 B
/ LABORATORY STUDY
/ ALGAL GROWTH POTENTIAL
BLUE RIVER ARM WATER
0.34
I
0.38
I
B - 3
0.36 0.38 0.40
TOTAL NITROGEN, mg/l
-49-
I
0.42
0.44
-------
0.30-
0.48
0.40-
>- 0.39-
< 0.30-
|
LEGEND
0.28-
Ul
(9
UJ 0.20-
0.18-
0.10-
0.05-
0
01
N*0.3lmg/l
N«0.26mg/l
N«0.22mg/l
N«0.2lmg/l
FIGURE 14 A
LABORATORY STUDY
ALGAL GROWTH POTENTIAL
FRISCO BAY WATER SAMPLE
Initial Phosphorus Concentration .016 ma/I
Initial Nitrogen Concentration * 0.2lmg/l
0.02
o:os 0.04
P.mg/l
-50-
0.08
0.06
B - 9
0.50-
0.45-
0.40-
0.35-1
UJ
0.30-
0.25H
HI
o
0.20-
0.15-
0.10-
LEGEND
P= 0.066 mg/l
O P=0.026 mg/l
£ P = 0.2I mg/l
O P=O.OI6mg/l
A
FIGURE I4B
LABORATORY STUDY
ALGAL GROWTH POTENTIAL
FRISCO BAY WATER SAMPLE
Initial Phosphorus Concentration * 0.016 mg/l
Initial Nitrogen Concentration «0.21 mg/l
0.03-j r
0.20 0.22
1 1 1
0.24 0.26 0.28
TOTAL NITROGEN, mg/l
-51-
0.30
0.32
-------
0.45-
0.40-
035-
UJ
5
a:
030-
UJ
_,
0.25H
0.20-
0.15-
01
LEGEND
N=0.22mg/l
N=O.I7mg/l
N=O.I3mg/l
N=O.I2mg/l
O
FIGURE ISA
LABORATORY STUDY
ALGAL GROWTH POTENTIAL
MAIN BODY WATER SAMPLE
Initial Photphorui Concentration * .OI2mg/l
Initial Nitrogan Concentration = O.I2mg/l
0.02
0.03
0.04
P,mg/l
0.05
-52-
0.06
B - 10
0.45-
0.40-
0.20-
0.15-
LEGEND
P = 0.062 mg/l
O P = 0.022 mg/l
A P = 0.017 mg/l
O P= 0.012 mg/l
FIGURE I5B
LABORATORY STUDY
ALGAL GROWTH POTENTIAL
MAIN BODY WATER SAMPLE
Initial Phosphorus Concentration*0.012 mg/l
Initial Nitrogen Concentration * 0.12 mg/l
-O--
0.12
I 1
0.14 0.16
0.20
TOTAL NITROGEN, mg/l
-53-
-------
500--
FIGURE 16
RATIO OF RESULTANT CONCENTRATION
OF CHLOROPHYLL Vond INITIAL CONCENTRATION
AT VARIOUS GROWTH RATES AND TIME.
8 100-
10--
o
o
>~»
5
10
of nUrogen in conjunction with phosphorus loading could be expected to fur-
ther stimulate algal growth. Nitrogen addition by itself produced no signi-
ficant change in growth rate over that which occurred under existing condi-
tions of nitrogen and phosphorus concentrations. It appears that after a
significant amount of phosphorus is present, nitrogen becomes more limit-
ing. Although the data may be somewhat ambiguous, increases in nitrogen
produce significant increases in growth rate when phosphorus levels are
high. This point is defined by the point of decreasing slope in Figures ISA,
14A and ISA. A similar phenomena was observed in a similar analysis per-
formed on Burntside River water near Ely, Minnesota (18).
Considering all samples, the greatest rate of change in growth rate occured
between existing concentrations of nutrients and those which resulted from
the addition of 0.05 mg/1 phosphorus in combination with those levels of nitro-
gen added, I.e., 0.01, 0.05, and 0.1 mg/1. The water samples without addi-
tions of nutrients showed an average increase in chlorophyll £ concentrations
of approximately 20% per day while those with nitrogen and 0.05 mg/1 of phos-
phorus showed increases of 35% per day. Assuming a constant growth rate over
a period of seven days with the additional concentrations of phosphorus and
nitrogen, the chlorophyll a. concentration could increase approximately eight
times over initial levels. It can be concluded that if such conditions were
to occur 1n the reservoir, 1t could be considered a substantial algae "bloom".
It 1s Interesting to note that the water quality study of Dillon Reservoir
discovered large phytoplankton populations during the July, 1973, survey. A
minimum of 1348 and maximum of 3328 cells per milliter was observed. The
-55-
B-H
-54-
-------
definition of an algae bloom proposed by Lackey (1945) was that point when
an organism reached or exceeded a population density of 500 per milliter.
Based on the above discussion and laboratory results, it is apparent
that it is desirable to maintain or decrease current levels of nutrients
to keep algal growth rates at the lowest possible level.
A considerable amount of the literature has been concerned with the re-
lationship of nutrient levels to algal growth. All recognize that the major
nutrients are phosphorus, nitrogen and carbon with several trace elements
being extremely important in growth kinetics also. Research in Lake Sebas-
ticook 1n Maine indicated that a reduction 1n phosphorus was necessary to
reduce severe algal nuisances. A total phosphorus objective of 0.02 mg/1
was established based on nearby lakes with the phosphorus concentrations
less than 0.02 mg/1 without algae problems (13). However, there may be sig-
nificant differences between growth relationships in low and high altitude
lakes.
Kuentzel has indicated that, "While phosphorus is a necessary element
for algal growth, the amounts required to support massive blooms are quite
low, approximately 0.01 mg/1". Kuentzel shows that carbon dioxide is also
a major nutrient required for algal growth (10). The critical concentration
level of phosphorus to inhibit algal growth remains 1n question. It has
been considered by some as 0.01 mg/1, yet growth in lakes has persisted with
no change in the amount of bloom when concentrations in the receiving waters
was reduced from 0.50 to 0.07 mg/1 (21). other investigations indicated
that nitrogen should be below 0.10 mg/1 and phosphorus less than 0.01 mg/1
with essentially no iron present, If nutrient scarcity 1s to prevent algal
growth (17).
-56-
The Environmental Protection Agency's National Eutrophication Survey
has analyzed and classified a number of lakes encountered in the program
to date as to their trophic state. The phosphorus concentrations in par-
ticular have been examined in relation to the trophic state and are shown
in Figure 17. Although the various classifications and phosphorus concen-
trations overlap, the mean of values observed give a basis for comparison.
Under the design conditions of this study, given in Section C of this
Chapter, the highest phosphorus concentration in portions of Dillon Reser-
voir results 1n a level greater than the mean of meso-eutrophic lakes ob-
served but significantly less than the mean of eutrophic lakes. This does
not mean that the observed meso-eutrophic lakes could not become eutrophic
with time. Of interest also 1s the fact that the phosphorus concentration
observed In 1973 In Dillon Reservoir and the calculated 1977 level of phos-
phorus in the Blue River Arm and Main Body is higher than the concentrations
in all oligotrophic lakes observed. The mean value of phosphorus in the
oligotrophic lakes was approximately 0.008 mg/1 while that in eutrophic
lakes was 0.12 mg/1. The calculated levels of. phosphorus 1n various por-
tions of Dillon Reservoir are shown on Figure 17.
Information from the National Eutrophication Survey indicates that in
phosphorus limiting situations, the nitrogen/phosphorus ratio 1s from one
(1) to greater than fourteen (14). The 1973 EPA survey showed the ratio to be
from 10 to 19 in Dillon Reservoir. Nitrogen limitation generally results
in a N:P ratio less than 14.
-57-
-------
CO
OL CO
CO (T
t §s
O
Q.
a:
o
Q.
O
_l
< UJ
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5^
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o
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£E
I-
^
1
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£
s
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^ § w
o e « «
° 3 13!
DC 5 c
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Q- o
CO >. £
SI £
Q. tO -5
UJ
> 2
Q) O
I 1
o
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^ O
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o ro
-*-» CD
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e cu
o ^
-------
If this idealized relationship adequately represents phenomena in the
natural setting, addition of nutrients by cultural activities should cause
the curve to begin a positive rise again after the cycle shown is completed.
It will, however, rise to a higher level than before. Without control mea-
sures, this increasing cycle will continue until a balance is reached.
B. Stream Response to Waste Loading
All flowing water has some degree of self-purification or waste assim-
ilation ability. The degree of waste assimilation capacity or ability de-
pends on four major factors :
1. Stream and drainage basin runoff characteristics.
2. Time of passage downstream.
3. Water temperature.
4. Reaeration.
None of the above factors behave the same in all drainage basins nor
do they necessarily have the same characteristics within all parts of a
given basin. In the natural setting, waste assimilation capacity is not
a fixed quantity but rather a range in potential that depends on variations
in size and behavior through each separate reach of the river (21).
Self-|*urifi cation is, to an extent, different for each type of waste.
Generally, municipal and domestic discharges are composed of chemical, . :c-
terial, and organic wastes. Stable chemical wastes undergo little or no
change during travel down the river. Dilution is the primary factor and
self-purification is almost wholly dependent on streamflow along the course.
-60-
Dilution of bacterial wastes also occur but time of exposure to the stream
environment and water temperature also act to change the characteristics
of bacterial wastes. Self-purification of unstable organic matter is a bio-
chemical process of decay. Oxygen dissolved in the river water is utilized
in tha stabilization of the organic matter which is carried out by biologi-
cal organisms. The stabilization is time and temperature dependent. The
depleted oxygen is replenished through the complex phenomenon of reaeration
from the atmosphere. This particular function is also temperature depend-
ent (21).
Consider the four major factors affecting stream self-purification;
first, stream and drainage basin characteristics. When considering waste
assimilation by streams, minimum dilution will produce the highest concen-
trations of waste materials 1n the water body. To analyze this effect of
minimum dilution, some minimum or drought streamflow must be considered.
Many agencies including the Colorado Department of Health have adopted the
seven-day, ten-year low flow as a general criteria for evaluating stream
waste assimilation capacity. This is the minimum flow occurring during a
period of seven consecutive days and having a statistical return period of
ten years. Possibly it could be better described by saying that there is
a ten percent probability of this minimum flow condition occurring in any
one year.
Generally, in most river basins, this particular hydrologic condition
occurs during the later part of the summer when low flow and high air and
water temperatures occur simultaneously. In the Blue River Basin, this is
generally not the case. The minimum flows occur in the late winter and early
-61-
-------
spring just before the snowmelt begins. Hater and air temperatures are
normally at 0°C or below at this time of year. This low temperature has
inhibiting effects on stabilization of organic matter and tends to slow
the death rate of bacteriological wastes.
In the upper portion of the Blue River Basin, the following stream
flow rates (Table 9) have been used in the determination of stream waste
assimilation capacity. The flows are calculated at the historic conflu-
ence of the three streams which are tributary to Dillon Reservoir.
TABLE 9
7-DAY, 10-YEAR DROUGHT FLOW DATA
FOR UPPER BLUE RIVER BASIN
(Source: U.S. Geological Survey)
Basin
Drainage
Area, mi'
128
111
57.5
92
Flow, cfs
13.0
11.1
6.65
10.6
cfs/mi2
0.102
0.100
0.116
0.116
Upper Blue River
(090470)
Tenmile Creek
(090505)
Snake River Near Monte-
zuma (090475)
Snake River at Dillon*
* Derived from cfs/m12 9 090475.
!i2te: 1 square mile (mi2) = 259 hectares
1 vjbic foot per second (cfs) » 0.0283 cubic meters per second (cms)
-62-
P - 15
Since operating agreements between the Denver Water Board and the U.S.
Bureau of Reclamation and other agencies allow less than 50 cfs outflow from
Dillon Reservoir if the inflow is less, it is conceivable that the outflow
from Dillon Reservoir could be approximately 34.7 cfs.
Reservoir relationships to streamflow rates are somewhat different. A
flow-through rate which will expose the entire body of water to a complete
cycle of reservoir operation is desired to examine the optimum effect on water
quality. Here the second major factor of time of passage is very important.
In the case of a stratified reservoir, a complete cycle is approximately one
year, being characterized by the autumn overturn cycle.
The first step is to determine the level of acceptance of risk, that is
the probability that such a low flow condition will occur. In this study, a
ten-year return frequency or 102! chance of occurrence 1n any one year has been
used. The duration is then determined by the desired detention time in the
reservoir. In this analysis a given consecutive period of average low flow
was analyzed for both reservoir detention time and return frequency. Table
10 gives the inflow rates used in the reservoir analysis. All detention
times approach one year with a 10-year average annual low flow. The Snake
River arm has a detention time of one year with a 10-year low flow having a
duration of eleven consecutive months. An average annual flow was used in the
reservoir analysis, however, because of the "flushing" action which will occur
in this arm during spring runoff. The detention time 1n the Tenmile Creek
arm (Frisco Bay) is also somewhat less than a year for an inflow with a dura-
tion of twelve months and return period of ten years.
-63-
-------
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a
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jo
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d S-
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5 III
3
H £
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C -C
SH O +J
-t- C
II*
VI 4U
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'~'.S<12
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(A
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"clit:
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iS
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ullr
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O O i-
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I i
to at
Wu
5-5
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*C Si
- £
o en i o>
» rj ^o oo r
CM «Jh 00
CM 00 «» «t
00 CJ CO 00 O
CM
CM r- CM CM CM
ill!
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| 1 « £4
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Second, waste assimilation 1n streams 1s affected by time of passage
downstream. The time of passage downstream 1s generally related to exam-
ining the location of effects of waste loadings on the stream. For Instance,
time of travel may be extremely Important In selecting a new wastewater
treatment plant outfall location so as not to produce effects which coin-
cide with those produced by upstream waste discharges. Velocity Is also re-
lated to reaeratlon capability of a given body of water. Time of exposure
of waste material between outfall to deposition 1n a quiescent body of water
Is also very Important. In the Blue River Basin, on the average, the stream-
beds have sufficient gradient to maintain velocities greater than one foot
per second.
Thirdly, water temperature affects the rate of reaction of the self-
purification ability of the streams. Low temperatures tend to Inhibit and
high temperatures tend to accelerate the rates of reaction such as stabili-
zation of organic matter and bacteriological purification. The general ex-
pression for the effect of temperature on reaction rate. K 1s
J<1_
"<2
e
-64-
B - 16
where K] and Kg represent the reaction constants at temperature T-| and Tj
respectively, and 9 1s the temperature coefficient, which Is normally 1.047.
Thus, the reaction rate at 5°C Is only 50% of that at 20°C and Is 582 great-
er at 30°C than that at 20°C. Temperature obviously has significant effects
on formation of 1ce cover on the body of water. Reaeratlon 1s affected by
temperature because the solubility of oxygen varies with temperature, being
-65-
-------
less at higher temperatures. Temperature within a lake or reservoir effects
stratification and flow patterns as previously discussed.
Because of the climatology, water temperatures do not vary over a wide
range In the Blue River Basin. For Instance, historical STORET Water Qual-
ity Data Indicates that the temperature of the Snake River at Dillon Reser-
voir varies between 28C and 15°C. Water temperatures below Green Mountain
f
and Dillon Reservoir are highly Influenced by the reservoir operation. Fig-
ure 19represents the average monthly outlet temperature from Dillon Reservoir
during water year 1973. As long as water 1s being withdrawn from the outlet
works, temperatures remain between 3°C and 6°C. However, when the reservoir
begins to spill, the warmer water at the surface of the reservoir raises the
temperature 1n the river downstream from the dam to approximately 15°C.
During the summer months, the temperature In the Blue River midway between
Dillon and Green Mountain 1s approximately 8°C. Green Mountain Reservoir
operation 1s such that It does not often spill, thus outlet temperatures are
assumed to be on the order of 6°C to 10°C throughout the year. Temperatures
1n the Blue River just upstream from Its confluence with the Colorado River
range from 0-1°C In the winter months and up to 12°C In the late summer.
Fourth, reaeratlon Is a complex phenomena requiring complex analysis,
however, certain general observations can be made. Oxygen from the atmos-
phere enters a body of water In the form of dissolved oxygen at the air-
water Interface as an Infinitely thin film that 1s Instantaneously complete-
ly saturated. Subsurface diffusion then carries the dissolved oxygen to
lower depths In the body of water. Mixing by streamflow turbulence does not
alter the function of diffusion but complements It by moving the Infinitely
-66-
B-17
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-------
thin surface film throughout the zone of mixing. In streams this is nor-
mally a large percentage of the total depth, while in reservoirs the zone
of mixing may be limited by wind and surface action to a relatively thin
layer near the water surface. The amount of oxygen going into solution at
any given time and point is a function of many parameters. The most con-
stant and predictable factor is the effect of dissolved oxygen levels ex-
isting in the body of water at any given time. Since the atmosphere con-
tains a relatively constant concentration of oxygen at all times, the amount
going into solution will increase if the levels in the stream are less than
saturation values and decrease as the dissolved oxygen levels approach sat-
uration. This particular function is also temperature dependent. It is
possible for water to become "super-saturated" as measured by analytical
techniques. This condition may occur from air entrainment by very turbulent
flow or by dissolution of pure oxygen produced by photosynthetic activity.
When there is an oxygen demanding substance in the stream, dissolved
oxygen is utilized to satisfy this demand resulting in depressed dissolved
oxygen levels. As discussed before, dissolved oxygen supplied by reaera-
tion would then Increase. This complex phenomena has been expressed by the
following equation.
A.dx A
where D = Cs - C
± Sd
Sd + Sbenthal -
Cs = saturation concentration of dissolved oxygen for a given temper-
ature and pressure.
C * dissolved oxygen concentration 1n receiving water
-68-
B - 18
0, » average flow rate
A = cross - sectional area of flow
Kd = rate of deaeration; deaeration coefficient
Ka = rate of atmospheric reaeratlon; reaeration coefficient
tt y
L = L e 6 = rate at which BOD disappears from overlying water.
Sd = distributed source of DO deficit
sbenthal = °° deficit by benthal demands
P = photosynthetic oxygen production
R = respiration - deoxygenatlon
The reaeratlon coefficient expresses the amount of oxygen added to the
system from the atmosphere. The coefficient is considered to be proportion-
al to the stream velocity and inversely related to the average depth of the
stream. Various formulations have been made of the reaeratlon coefficient
K among which is the 0'Conner-Dobbins formulation for base e computations
3
where
12.9 U
,1/2
H
JJT
where, U = streamflow velocity 1n feet per second
H - effective depth In feet, calculated from the cross-
sectional area divided by the top width of the stream.
Using this expression, the reaeratlon coefficient of streams for var-
ious locations 1n the Blue River Basin 1s given in Column 4. Table 11. This
formulation 1s given in graphical form 1n Simplified Mathematical Modeling,
gf Water Quality published by the Environmental Protection Agency (20).
Values from that source are given for comparison 1n Column 5 of Table 11.
-69-
-------
The equation given for predicting dissolved oxygen relationships 1n
streams also Includes a deaeratlon coefficient, Kd. This 1s a measure of
the rate of utilization of oxygen by the oxygen demanding material. The
source of oxygen demanding material normally Includes external waste loads
only as distributed sources, benthal demands, and respiration are accounted
for by other terms 1n the equation. The deaeratlon coefficient has been
found to be highly dependent on the stream bed characteristics and type and
strength of waste exposed to the stream environment. For streams 1n the
Blue River Basin, Kd would be 1n the range of 1.0 to 2.0, the higher values
being associated with very rocky stream beds.
TABLE 11
REAERATION COEFFICIENT, 1C, IN THE BLUE RIVER BASIN
a
(1)
Location
Snake River upstream of
Dillon Reservoir
(2)
Velocity
(fPS)
1.3
(3)
Depth
0.9
(4)
Mday"1)
17.2
(5)
11.6
Blue River midway between
Green Mountain Reservoir
and Dillon Reservoir
Blue River near confluence
with Colorado River
1.8
3.5
1.8
1.6
7.2
11.9
8.1
10.1
The ratio of Ka to Kd 1s a fundamental Indicator of river capacity for
waste assimilation. High values Indicate high self-purification capabilities
and generally are associated with small depth and high to medium velocities.
Using coefficients previously given, the ratio Ka/Kd is given in Table 12
for various locations in the Blue River Basin.
TABLE 12
REPRESENTATIVE ASSIMILATION RATIOS Ka/Kd
FOR BLUE RIVER BASIN
Location
Ka/Kd
Snake River upstream from Dillon
Reservoir
Blue River midway between Green
Mountain and DUlon Reservoir
Blue River near confluence with
Colorado River
17.2
7.2
11.9
1.7
1.2
1.3
10.1
6.0
9.2
-70-
B - 19
C. Calculation of Water Quality Response to Waste Loads
1. Dillon Reservoir and Green Mountain Reservoir.
Based on the foregoing discussion, concentrations of various wastewater
constituents were calculated in Dillon and Green Mountain using a completely
mixed system analysis. There are certain disadvantages with this particular
approach, however, with the data base existing at this time, a more sophisti-
cated approach may not yield results with a higher degree of resemblance to
actual conditions. Reference 1s made to the Water Qaullty Analysis of Summit
-71-
-------
County (1) published by E.P.A. for a substantial discussion of the proposed
method of analysis if sufficient data were available.
Certain assumptions and criteria have been made in this analysis. The
wastewater discharge quality used in the analysis is that given in Table 13.
This assumes phosphorus removal efficiencies of approximately 95% since phos-
phorus has been shown to- be a cause for algal growth and removal from waste-
water is deemed necessary at the outset of the analysis. Removal of biochem-
ical oxygen demanding material is assumed to be approximately 92% with efflu-
ent concentration of 5-Day BOD of 20 mg/1. These parameters are in accor-
dance with current 1978 Colorado State standards and more stringent than
applicable criteria set for secondary treatment by the Environmental Protec-
tion Agency.
With the population and wastewater loadings given and the hydrologic and
physical characteristics given for the reservoirs, Table 14 shows the resul-
tant concentrations of various waste loading materials discharged to the res-
ervoirs under various conditions. The analysis is detailed in the Appendix.
The analysis represented in Table A-C-1 of the Appendix assumes wastewater
discharge directly to Dillon Reservoir from tributary basins and directly to
the Blue River from wastewater treatment plants located downstream from Dil-
lon Reservoir. The results shown are from the completely mixed analysis.
The flow applied to Green Mountain Reservoir is the average flow required to
be released from Dillon Reservoir to fill Green Mountain, 214 cfs, plus the
10-year Tow flow added by the tributary drainage area between Dillon and
Green Mountain. Background loading applied to Green Mountain includes the
discharge from Dillon Reservoir resulting from waste discharge described
above.
-72-
Tables A-C-2 through A-C-4 consider the impact of wastewater diversion
around Dillon Reservoir to the lower Blue River Basin and the development
of additional water resources which would direct more water of relatively
high quality into Dillon Reservoir. The impact of these alternatives is also
examined for Green Mountain Reservoir.
TABLE 13
WASTEWATER TREATMENT PLANT DESIGN EFFLUENT QUALITY
Constituent
5-Day Biochemical Oxygen Demand
Suspended Solids
Phosphates, as P (95* Removal)
Total Nitrogen, N
Concentration
20 mg/1
20 mg/1
0.375 mg/1
20 mg/1
This analysis considers phosphorus and nitrogen to be conservative
substances, I.e. the reaction rates are equal to zero.
2. Blue River and Tributaries.
Stream water quality may be most effected by the discharge of unstable
organic wastes. As indicated previously in Table 12, the assimilation
ratios for streams in the basin are high. As an example, the resultant
dissolved oxygen level in a portion of the Upper Blue River Basin was cal-
culated by methods given 1n Simplified Mathematical Modeling of Water Qual-
ity for a discharge of a quality only in conformance with presently estab-
lished secondary treatment standards, i.e. 30 mg/1 of 5-day BOD.
-73-
-------
TABLE 14
SUMMARY
NUTRIENT CONCENTRATIONS IN DILLON AND
GREEN MOUNTAIN RESERVOIRS UNDER VARIOUS CONDITIONS
Location
Dillon Reservoir
(a) Blue River Arm
(b) Snake River Arm
(c) Tenmlle Creek Arm
(d) Main Body
Green Mountain Reservoir
1973 Survey -
Ex1st1nq Cone.
P
0.013
0.010
0.020
0.013
N
0.26
0.22
0.25
0.19
--
Condition A1
1977
P
0.017
0.016
0.018
0.017
0.016
N
0.61
0.64
0.46
0.56
0.51
1992
P
0.035
0.021
0.020
0.026
0.023
N
1.57
0.95
0.60
1.06
0.92
Condition B1
1977
P
0.017
0.016
0.018
0.017
0.016
N
0.61
0.64
0.46
0.56
0.51
1992
P
0.035
0.021
3.015
0.021
0.022
N
1.57
0.95
0.39
0.79
0.85
Condition C1
1977
P
0.017
0.016
0.018
0.017
0.022
N
0.61
0.64
0.46
0.56
0.63
1992
P
0.009
0.007
0.013
0.010
0.023
N
0.17
0.18
0.21
0.19
0.90
Condition D1
1977
P
0.017
0.016
0.018
0.017
0.022
N
0.61
0.64
0.46
0.56
0.63
1992
P
0.009
0.007
0.011
0.010
0.025
N
0.17
0.18
0.20
0.19
1.02
1 Condition A: All wastewater 1n three upper basins discharged directly to Dillon Reservoir and no further water resource developments dis-
charging to or withdrawing from Dillon Reservoir.
Condition B- All wastewater 1n three upper basins discharged directly to Dillon Reservoir and water resource developments directing addi-
tional high quality water to Dillon Reservoir 1n 1992.
Condition C- All wastewater 1n three upper basins diverted around Dillon Reservoir and discharged to Lower Blue River and no further water
resource developments discharging to or withdrawing from Dillon Reservoir.
Condition D- All wastewater 1n three upper basins diverted around Dillon Reservoir and discharged to Lower Blue River and water resource
developments directing additional high quality water to Dillon Reservoir 1n 1992.
NOTE: Under all conditions examined, no additional water resource developments were considered 1n 1977.
B - 21
-------
DISSOLVED OXYGEN ANALYSIS
UPPER BLUE RIVER BASIN
Design Criteria:
1. Drought Strearaflow at River Mile 9.4
Upper Blue Rfver Basin = 1.8 CFS
2. Wastewater Discharge Flow = 25,000 GPD
3. Background BODU = 1.5 mg/1 = 14.6 Ibs/day
4. Background DO Deficit = 1 mg/1
5. BODU from Wastewater Discharge = 45 mg/1 = 9.4 Ibs/day
6. Average Streamflow Velocity = 1.5 ft/sec.
7. Average Stream Depth = 0.7 feet
8. Reaeration Coefficient, Ka, at 3°C = 5.9 day"1
9. Deaeration Coefficient, Kd, at 3°C = 0.9 day"1
10. Assimilation Ratio « 6.6
The resultant maximum dissolved oxygen deficit is equal to approximately
1.3 ng/1 and occurs approximately 9.3 miles downstream. The minimum dissolved
oxygen level would be 8.0 mg/1 or approximately 80% of saturation. As can be
seen, the effect of this type of waste loading is somewhat minimal.
The other area of concern in regard to stabilization of organic wastes
would be the segment in the Lower Blue River Basin between Dillon Reservoir
and Green Mountain Reservoir. Assume the following wintertime design condi-
tions in this segment with the 1992 projected wastewater flow in this segment.
1. Minimum Streamflow =
2. Wastewater Discharge =
3. Background BODU » 1.5 mg/1 =
4. Background DO deficit =
5. BODU from Wastewater Treatment
Plants = 30 mg/1 (1978 State Stds.)
at MP 38.7 =
at MP 34.0 =
6. Average Streamflow Velocity =
7. Average Stream Depth =
.8. Reaeration Coefficient, Ka, at 3°C
9. Deaeration Coefficient, Kd, at 3°C
10. Assimilation Ratio «
34.7 cfs
4.0 MGD at MP 38.7
1.0 MGD at MP 34.0
282 Ibs/day
1 mg/1
1000 Ibs/day
250 Ibs/day
1.8 fps
1.8 feet
3.3 day"1
0.55 day'1
6.0
-75-
With the above design criteria, the maximum dissolved oxygen deficit 1s
1.64 mg/1 located at approximately river mile 19.5. This is theoretically
within Green Mountain Reservoir. The normal mathematical model used to ex-
press dissolved oxygen deficit is not applicable to the area within the res-
ervoir and cannot accurately express dissolved oxygen relationships. Just
upstream from Green Mountain Reservoir at river mile 22.7, the dissolved
oxygen deficit is 1.63 mg/1 with approximately 6.6 mg/1 of ultimate oxygen
demand remaining.
As can be seen, with maximum loading and minimum Streamflow, the dis-
solved oxygen standard of 6.0 mg/1 1s not violated. Of concern, however is
-76-
B - 22
-------
the oxygen demanding material discharged Into the qulscent bodies of water.
Due to the low temperatures, reaction rates are low and the oxygen demand
will persist for extended periods of time. The nitrogenous oxygen demand
will be particularly sensitive as low temperatures inhibit natural nitrifi-
cation. The flow and duration criteria used in stream analysis cannot be
used in reservoir analysis, however. Thus the maximum Input under severe
streamflow conditions may be offset by dilution and Inflow of a greater
concentration of dissolved oxygen during the total period required to sat-
isfy the oxygen demand 1n the reservoir.
Ammonia and its associated toxlcity has been recognized as a potentially
serious problem 1n areas which receive considerable use as fisheries. The
Environmental Protection Agency has recommended that a maximum allowable
concentration of unionized ammonia be considered as 0.025 mg/1. The
degree at 1on1zat1on is highly dependant on the water temperature and pH.
Other factors such as dissolved oxygen, alkalinity, free carbon dioxide,
sodium ions, and other physiological factors have additional effects on the
overall toxiclty of ammonia to aquatic organisms (24). Under design condi-
tions, ammonia toxiclty is not considered to be a severe problem in the
Basin.
Using the following design criteria, it 1s apparent that an acceptable
ammonia concentration in the wastewater effluent 1s possible with a well
.operated activated sludge treatment facility.
Lower Blue River streamflow « 34.7 cfs
Ammonia concentration 1n stream - 0.05 mg/1
1992 wastewater flow « 4 M6D
Stream temperature » 15° C
Stream pH 7.8
-77-
Under these conditions, an ammonia nitrogen concentration of 7.75 mg/1 1n
the wastewater effluent must not be exceeded to maintain a maximum allow-
able concentration of 1.22 mg/1 in the stream. Under the given conditions
of temperature and pH, an ammonia nitrogen concentration of 1.22 mg/1 will
result in an un-lonlzed ammonia concentration of 0.025 mg/1.
B - 23
-78-
-------
CHAPTER V
WASTE LOAD ALLOCATIONS
Allocation of waste loading to various discharge points is desired to
meet and maintain all applicable water quality standards. This includes
provisions which provide that the waters shall be free from substances,
"... which produce undesirable aquatic life". Based on data and analysis
presented in this report, allocation of waste loads to various portions of
Dillon Reservoir has been performed based on a proration of projected average
daily flow rates in the year 1977. This load has then been allocated to
individual discharges in each basin on the basis of present design plant capa-
city. The maximum discharge of nutrient materials to Dillon Reservoir is
allocated so as to maintain levels of nutrients which are considered accep-
table by comparison with those found in the water quality survey of 1973, and
those given in Figure 17.
Because of the determination of phosphorus limitation, phosphorus only
is being allocated at this time. Due to the recognized variation in waste-
water flow, the concentration of this constituent should be the major indi-
cator of waste load allocation conformance because daily calculation year-
round of total load would not necessarily reflect the required conditions.
-»
In addition to this, peak daily waste loads may exceed the average daily
waste load given by no more than a factor of 1.29. This is based on the pop-
ulation estimates previously presented in this study. This will account for
larger than average loads discharged during the peak flow periods represented
in Figure 11. The annual daily average loading must not exceed the load
allocations given.
-79-
Table 15 gives the domestic waste load allocation of phosphorus to
various portions of Dillon Reservoir. Tables 16 and 17 use this Informa-
tion and present design plant capacity to allocate the average daily waste
discharge.
Allocations have been made to all current waste dischargers. The Water
Quality Management Plan for the Blue River Basin has evaluated several al-
ternative management schemes and has recommended the phasing out of opera-
tion of several small wastewater treatment plants in the Basin and connection
of these facilities to sub-basin regional treatment plants. Of the existing
treatment facilities listed 1n Table 16, all are to be phased out of opera-
tion by 1977 with the exception of the following:
1. Breckenrldge Sanitation District Plant at Swan Mountain Road.
2. Summit County Phase "D" at the Snake River.
3. Arapahoe Basin.
4. Frisco Sanitation District Plant at Frisco.
5. Copper Mountain Water and Sanitation District Plant at Wheeler
Junction.
Allocations of biochemical oxygen demand (BOD), suspended solids, tur-
bidity, and conform bacteria will be in accordance with current state and
federal standards for secondary treated wastewater discharges. These are
given 1n Table 18.
TABLE 15
DOMESTIC WASTE LOAD ALLOCATION OF PHOSPHORUS TO DILLON RESERVOIR
Average Allowable
Loading, Ibs/day
1977 1992.
Location
Blue PJver Arm
Snake River Arm
Tenrolle Creek Arm
Main Body
Concentration mg/1
0.013 1.88 2.18
0.010 0.67 0.70
0.015 1.00 1.05
0.013 14.6 15.0
Tributary Arms are Critical Areas
-80-
-------
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TABLE 17
DOMESTIC WASTE LOAD ALLOCATION OF PHOSPHORUS TO
DISCHARGERS TO LOWER BLUE RIVER BASIN ABOVE
GREEN MOUNTAIN RESERVOIR AND RESULTANT RESERVOIR CONCENTRATIONS IN 1977
(With Proposed Allocations to Dillon Reservoir given in Table 16)
Location
Lower Blue River Basin
Silverthorne San. Dist.
Average P
Discharge
Ibs/day
3.13
Maximum
Effluent
Concentration,
mg/1
0.375
Resultant
Concentration,
mg/1
in Reservoir
0.013
Silverthorne San. Dist. 3.13
Future discharge between
Silverthorne plant and
Green Mountain Reservoir 2.76
0.375
0.375
0.014
-81-
B - 25
-82-
-------
TABLE 18
MAXIMUM CONCENTRATIONS OF VARIOUS CONSTITUENTS
FROM ALL UASTEWATER DISCHARGES IN THE
BLUE RIVER BASIN
Present
1975
1978
\j\JI 13 If 1 t-LIGM U
5-Day BOD
Suspended Solids
Turbidity
Fecal Col i form
pH
30 mg/1
30 mg/1
30 JTU*
5000 **
6.0 - 9.0
25 mg/1
25 mg/1
25 JTU
5000
6.0 - 9.0
20 mg/1
20 mg/1
20 OTU
5000
6.0 - 9.0
* JTU = Jackson Turbidity Units
** Fecal coliform bacteria per 100 milliliters as calculated by the geo-
metric mean for samples collected during 30 consecutive days.
Note: Standard given is State of Colorado Standard. Environmental Protec-
tion Agency standard for secondary treatment is 200 per 100 ml.
CHAPTER VI
FUTURE EVALUATION AND RESEARCH
Discharge Permit Review
Title IV of the Federal Water Pollution Control Act Ammendments of
1972 requires that all discharge permits issued and the conditions of
each permit shall be reviewed at the end of a fixed term indicated in the
permit. This period shall not exceed five years. Due to the apparent
sensitivity of Dillon and Green Mountain Reservoirs, it is strongly recom-
mended that permit conditions be evaluated at the end of a period not to
exceed three years, January 1, 1978, or that point in time when average
or peak flow rates of wastewater exceed those used 1n this report, whichever
condition occurs first. During the interim period, constant monitoring and
surveillance of water quality in the reservoirs and streams resulting from
discharge of wastewater effluent will be required.
As conditions of the discharge permit, wastewater quality and quantity
monitoring must be performed on all discharges. Accurate flow records
and quality analyses must be kept and submitted for record. During per-
iods of peak wastewater loading, daily flow records and effluent sample
analyses should be submitted for review and evaluation biweekly. Accurate
recording and reporting of wastewater flow is most important because of
the need for data to use in verification or adjustment of the data and
assumptions used in the current analysis. If population and wastewater
loading vary significantly from the quantities used 1n this study, revi-
sions in the allocations to dischargers may be necessary. Composite
-83-
B - 26
-84-
-------
effluent sample analyses should be submitted biweekly also. This period
of biweekly reporting would occur approximately from December through March
and June through August. Monthly reporting of daily flow records and com-
posite sample analyses would be possible during the remaining months of the
year.
3ec?use of the high level of treatment required by these waste load
?.: locations, conformance can only be expected from a properly managed and
operated treatment facility. Experienced, certified personnel will be re-
quired to operate all wastewater treatment plants in the Basin.
Research and Detailed Survey Needs
Fu,"ther research in both Dillon and Green Mountain Reservoir should be
pursued at once to determine correlations of laboratory and in situ condi-
tions of algal growth kinetics. Observation and measurement of phytoplank-
ton production in situ under known conditions may aid in further understand-
ing the characteristics of the reservoirs and their natural flora and fauna.
The effect of trace element limitation and further detailed nutrient-growth
relationships are of interest.
It is desirable to have the tools to accurately model the reservoirs re-
sponse to waste loading taking into account various conditions of climate,
hydrology, and resultant temperature stratification. To do so requires suf-
ficient data to calibrate and verify a model. Additional observations will
be required to gather this Information. Evaluation of the effect of long
term biochemical oxygen demand is of particular interest. Modeling of res-
ervoir response to oxygen demanding material discharged to the reservoirs
durins periods of very low temperature and complete ice cover is required
to properly access the impact of this type of waste loading.
-85-
BIBLIOGRAPHY
1. Anderson, Terry et.al, Hater Quality Management Analysis of Summit
County, Colorado, U.S. Environmental Protection Agency, Region
VIII and Colorado Department of Health* Water Pollution Control
Division. 1972.
2. Climatologlcal Data, 1972. United States Department of Commerce, Na-
tional Oceanic and Atmospheric Administration, Environmental
Data Service. United States Government Printing Office.
3. Colorado-Big Thompson Project. Volume 1_ - Planning, Legislation, and
General Description. United States Department of the Interior,
Bureau of Reclamation. Denver, Colorado, 1957.
4. Dillon Reservoir - Blue River^ Study Colorado, June, July, August, 1973.
Technical Investigations Branch, Surveillance and Analysis Division,
U.S. Environmental Protection Agency, Region VIII, January, 1974.
5. Fair, Gordon M., John C. Geyer and Daniel A. Okum, Water and Wastewater
Engineering. Volume 2 - Water Purification and Wastewater Treatment
and Disposal. John Wiley and Sons, Inc., New York, 1968, Pgs. 32-21
- 32-24.
6. Hendrlcks, E. L., et.al, Compilation of Records of Surface Waters of the
United States, October 1950 to. September 1960_, Part 9_, Colorado River
Basin. Geological Survey Water Supply Paper 1733, United States Gov-
ernment Printing Office.
-86-
P, - 71
-------
7. . Surface Water Supply of the United States, 1961 to 1965, Part
9_, Colorado River Basin, Volume 1_. Colorado River Basin above Green
River. Geological Survey Water Supply Paper 1924, United States Gov-
ernment Printing Office.
8. Interim Hater Quality Management Plan for the Blue R1_yer Basin, wUhin,
Summit County, Colorado, Board of County Commissioners, Summit
County, Colorado and Colorado Water Pollution Control Division.
March, 1973.
9. lorns, W.V., C.H. Hembree and G.L. Oakland. Water Resources of the Up^er
Colorado River Basin - Technical Report. Geological Survey Profes-
sional Paper 441, United States Government Printing Office, 1965.
10. Kuentzel, L.E., "Bacteria, Carbon Dixolde, and Algal Blooms", Journal of
the Mater Pollution Control Federation, Vol. 41, No. 10, October,
1969, pgs. 1737 - 1745.
11. Linsley, Ray K., Jr. and Max A. Kohler and Joseph L.H. Paulhus, Hydro-
logy for Engineers. McGraw Hill Book Company, New York, 1958.
12. Lucus, Therese C., Draft Technical Paper Mo. 2 Colorado Projections
1980. 1990. 2000. and Methodology. Unpublished report prepared
-» *~~ ~
for the Colorado Land Use Commission. November 16, 1972.
13. Mackenthun, Kenneth M., Lowell E. Keup, and R. Keith Stewart. "Nutrients
and Algae in Lake Sebasticook, Maine," Journal of the Water Pollution
Control Federation, Vol. 40, No. 2, Part 2, February, 1S68.
14. Maloney, Thomas E., et al. "Use of Algal Assays in Studying Eutrophi-
cation Problems." Advances In Water Pollution Research. Sixth In-
ternational Conference. June. 1972. Pergaraon Press, New York, 1973,
pgs. 205-214.
15. Maloney, Thomas E., William E. Miller and Tamotsu SMroyama. "Algal
Responses to Nutrient Additions in Natural Waters. I. Laboratory
Assays." Nutrients and Eutrophication Special Symposia, Volume !_
1972. The American Society of Limnology and Oceanography, Inc.,
pgs. 134-140, 154-156.
16. Markofsky, Mark and Donald R. F. Harleman, "Prediction of Water Quality
in Stratified Reservoirs," Journal of the Hydraulics Division, ASCE_.
May 1973, pgs. 729-745.
17. McGauhey, P.H., Engineering Management of Wa_ter Quality,. McGraw H111
Book Company, New York. 1968.
18. Miller, William E. and Thomas E. Maloney. "Effects of Secondary and
Tertiary Wastewater Effluents on Algal Growth in a Lake-River System".
Journal Water Pollution Control Federation, December, 1971, pgs.
2361-2365.
19. Scherfig, Jan, et.al Effect of Phosphorus Removal Processes on Algal
Growth, Office of Research and Development, U.S. Environmental Pro-
tection Agency, U.S. Government Printing Office, Washington, D.C.,
September, 1973.
-87-
P - 23
-88-
-------
20. Simplified Mathematical Modeling of Water Quality. U.S. Environmental
Protection Agency, March, 1971.
21. Velz, Clarence 0., Applied Stream Sanitation. Wlley-Intersclence, New
York, 1970.
22. Water Quality Standards and Stream Classification. Water Quality Con-
trol Commission, Colorado Department of Health, June 19, 1974.
23. Hells, J.V.B.. et.al. Compilation of Records of Surface Waters of the
United States through September 1950. Part 9_, Colorado River Basin.
Geological Survey Water Supply Paper 1313, United States Government
Printing Office.
24. WllUngham, Tom. Ammonia Toxlclty and Its Removal from Wastewaters.
Environmental Protection Agency, Region VIII, April, 1973.
-89-
E - 2Q
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APPENDIX "C"
-------
PROCEDURES TO BE FOLLOWED IN APPLYING FOR AN
INDIVIDUAL SEWAGE DISPOSAL PERMIT
1. Complete pages seven and eight of the application and return to the
Summit County Department of Environmental Health.
a. Refer to the attached sample plot plan and attached list of
specifications for assistance.
b. Incomplete applications will not be accepted.
2. The following are preparations to be made by the applicant at the
proposed building site.
a. The proposed location of the leach field, dwelling, and septic
tank shall be marked with four (4) corner stakes. Proposed
well locations and property lines shall be marked. The
absorption area shall be sized by the Summit County Department
of Environmental Health.
b. The percolation tests shall be run by a qualified Registered
Professional Engineer or a technician of the local Health
Department. In the event that the local Health Department performs
the percolation test the owner of applicant shall do the following:
1. Provide three (3) adequate percolation test holes to the
depth of the proposed leach field.
2. Pre-soak the three (3) percolation test holes at least eight
(8) hours prior to the test being conducted.
3. Provide the necessary water to fill the three (3) percolation
test holes. The fee for the percolation tests shall be set
by the Local Board of Health.
c. A profile test hole must be dug at a location 4' outside the sidewall
at the midpoint of the proposed leach field. This hole must be dug
to a depth of at least 4' below the bottom of the proposed leach
field. The hole must be large enough in diameter to permit visual
observation of the ground strata at all levels. The profile hole
must be dug to the proper depth and at the time, or prior to, per-
colation tests being made by the Department of Environmental Health.
Additional profile holes of a depth greater than 4' below the
bottom of the absorption area may be required by the sanitarian
based on need as determined by conditions at the site. This is a
test for subsurface water and impervious strata.
3. When the site preparation is completed, the applicant must contact the
Health Department between the hours of 8:30 A.M. - 9:30 A.M., and arrange
an onsite inspection and/or soil percolation tests 24 hours in advance of
requested inspection time. The onsite inspection and/or soil percolation
tests will determine the suitability of the site for the proposed individual
sewage disposal system.
4. If all conditions are favorable for a typical individual sewage disposal
system, the applicant can generally obtain his permit one or two days after
the visit by the sanitarian. Money for the permit issuance cannot be taken
by the inspecting Sanitarian when the onsite inspection is made, and at no
time prior to acceptance of the site for an individual sewage disposal
system.
If one or more of the following conditions exist at the site, then the
applicant will be refused a permit for a typical individual sewage disposal
system:
a. Soil conditions which prohibit subsurface disposal due to poor
percolation.
b. High ground water.
c. Insufficient depth of pervious soil.
d. The building site prohibits maintenance of minimum distances as
outlined on the attached sheet of specifications.
e. Excessive slope or other terrain problems in the area of the proposed
leach field.
f. Slope in excess of 30% or a percolation rate faster than five (5)
minutes per inch or slower than sixty minutes per inch.
If one or more of the conditions do exist, then the applicant must submit
a design for a sewage disposal system other than a typical septic tank and
leach field system. This design must meet all the requirements and speci-
fications as outlined in the "Manual of Septic Tank Practice", a Public
Health Service Publication #526. A Registered Professional Engineer shall
be required in designing a system of this type. If an applicant chooses,
he may retain a Registered Engineer at the beginning and have him conduct
the necessary tests and design a system for review by the Health Department.
This design must also meet all the requirements and specifications as out-
lined in the "Manual of Septic Tank Practices"; Public Health Service
Publication #S26, and the requirements of the Summit County Local Board of
Health concerning Individual Sewage Disposal Systems.
After installation and before backfilling, an appointment shall be made for
a final inspection 24 hours prior to requested inspection time by contacting
the inspecting sanitarian between the hours of 8:30 A.M. to 9:30 A.M. Refer
to the permit number when requesting final inspection. Craftsmanship of the
septic system installation and adherance of the permit requirements will be
examined at this time. No acceptence will be given on any system without
a final inspection, and a Certificate of Occupancy will be withheld by the
County Building Department.
Page 1
C -
Page 2
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and at angles greater than
THE FOLLOWING ARE SPECIFICATIONS REQUIRED BY SUMMIT COUNTY HEALTH
DEPARTMENT IN THE CONSTRUCTION OF INDIVIDUAL SEPTIC SYSTEMS
1. BUILDING SEWER (line extending from 10' outside of dwelling unit to septic
tank)
a. The grade of building sewer is at least 2% except the 10' immediately
preceding tank which does not exceed 2% slope.
b. Cast iron required through or under foundation.
c. Cast iron below driveway if less than 3' deep.
d. The diameter of the building sewer must not be less than the building
drain. 4" minimum.
e. Cleanouts provided at least every 100'
45 degrees.
f. Joints must be water tight and root proof.
g. Pipes under driveways or other surfaces which are usually cleaned of
snow must be insulated to prevent freezing.
2. SEPTIC TANK
a. Tank must meet minimum size as indicated on application.
b. Tank must be water tight and constructed of materials not subject to
excessive corrosion or decay.
The inlet and outlet of tank must be supplied with tees or baffles.
The inlet must enter at least 3" above the outlet.
All septic tank manholes and/or inspection ports shall extend to
within eight (8) inches below finished surface grade. At least one
access no less than 20 inches across shall be provided in each
compartment.
The tank must be at least two compartments.
Cast iron or pipe of equal crush weight must extend 5' from inlet and
outlet.or adequately supported to prevent failure due to ground settling.
3. EFFLUENT SEWER LINE (Line extending from septic tank to absorption area or
distribution box)
a. Effluent line must be water tight and root proof.
K Grade of effluent line is at least 2%.
The diameter of the line must be 3" minimum.
Pipes under driveways or other surfaces which are usually cleaned of
snow must be insulated to prevent freezing.
4. SEEPAGE BEDS AND ABSORPTION TRENCHES
a. Absorption area must meet minimum size as indicated on application.
D. The bottom of leacth FI*»T*I mtie+ KB IA..AI ««.i _i«,».j _* _ j ^i. _^
c.
d.
e.
f.
g.
b.
c.
d.
c.
d.
e.
f.
g-
h.
i.
j.
k.
1.
n.v *«> uiuoi. IIICGL minimum size as indicated on application.
The bottom of leach field must be level and placed at a depth of not
less*than 2' into virgin soil.
No part of leach field shall be placed in fill dirt, mine tailings, etc.
Minimum gravel depth 6" below lines, 2" above-lines. Total gravel
depth shall be 12".
Gravel size V to 2V clean.
Diameter of distribution lines is 3" minimum
Distance between distribution lines not greater than 6'
Distance between distribution lines and absorption area wall, maxi-
fliuin j t
Distribution lines leaving distribution box must be equal in length.
Length of distribution lines, maximum 100'.
Distribution lines must be even or level within box
Line entering distribution box must be above lines leaving distribution
box.
C - 2
Page 3
m. Acceptable material for distribution lines are as follows:
1. Plastic perforated pipe 600 Ibs. crush minimum.
2. Cement tile 1" x 4" section.
3. Vitrified clay sewer pipe in 2 to 3 ft. lengths.
n. Distribution lines must be connected or plugged at the ends to
make a water-tight seal.
o. The joints between cement pipe section must be covered with strips
of tar paper of similar material.
p. Minimum distance between tank and distribution box is 3'.
q. The bottom of the leaching facility excavation must be the same
level as the bottom of the percolation test hole.
r. Distribution line slope within the field shall not be more than
4" of drop per 100' of line.
s. Distribution lines and the gravel over the distribution lines shall
be covered with pervious material such as straw or degradable
building paper, effectively separating backfill material and field
gravel.
t. All smeared or compacted surfaces must be raked to a depth of one (1)
inch, and loose material removed, before gravel is placed.
5. SEEPAGE PITS
a. This type of absorption area is acceptable only when terrain or
usable absorption area is not suitable for leaching fields.
6. THE FOLLOWING MINIMUM DISTANCES MUST BE MAINTAINED:
a. 100" between any part of the absorption area and water well, cistern
or spring.
b. SO" between septic tank and water well, cistern or spring.
c. 25' between absorption area and water line.
d. 10' between septic tank and domestic water line.
e. 50' between septic tank and/or absorption area and water courses
(streams, lakes, based upon maximum seasonal elevation).
f. 20' between absorption area and buildings.
g. 5' between septic tank and buildings.
h. 10' between septic tank and property lines.
i. 10' between absorption area and property lines.
j. 25' between seepage pits and property lines.
k. SO' between seepage pits and domestic water lines.
1. 50* between building sewer and well.
m. 10' between building sewer and water supply line pressure.
n. 50* between building sewer and water course (stream, lake, etc.)
Based upon maximum seasonal elevation.
o. A minimum of 4' must be maintained between the bottom of the leach
field and any existing ground water.
p. 60' between septic or pre-treatmont tanks and lake water course or
stream in fractured or jointed bedrock. Based on maximum, seasonal
elevation.
q. 100' between absorption field, sand filter trench, pit privy or slit
trench and lake water courses or stream in fractured or jointed
bedrock, based upon maximum seasonal elevation.
r. 60' between building sewer and lake, water course, or stream in
fractured or jointed bedrock, based upon maximum seasonal elevation.
Page 4
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GUIDELINES
TABLE OF MINIMUM HORIZONTAL DISTANCES IN FEET BETWEEN COMPONENTS OP A SEWAGE DISPOSAL SYSTEM AND PERTINENT GROUND FEATURES
Springs, Wells or Suction
Lines.
Potable Water Supply Line
Cistern
Dwelling or Occupied
Building
Property Lines
Subsoil Drains
Lake, Water Course or
Stream.
Dry Gulches
«? ° c
aa-aa
H
t
50
25
SO'
50
10
25
5*
10*
101*10***
* so***
50
10
15
10
10
25
10' j 10*** 10 10 10
ration
Stabil
60
10.
25
15
10
10
25
.s§
-J W
B
c -o o H » h
H V .H -H P. U
l-l C *J r-l W JC
C *H (4 *H 'H *J
5-5 M ja o 0
60
10
15
10
10
25
X rl
a.i i °
I/I O
in S in
T> 4> p
C 4-1 ft
> in -H
3 O H
-I -rl M Ifl
A u .H i-i a x
< t/5 U. M M t/>
100
25
25
15
10
25
25
15
100
25
25
20
10
25
50
25
100
50
20
25
25
50
25
i
32
8'S-S
0) .H S
O.-H ,2
IA >H
-------
If an applicant chooses, he may retain a registered engineer
at the beginning and have him conduct the necessary tests
and design a system for review by the Health Department.
This design must also meet all the requirements and specifications
as outlined in the "Manual of Septic Tank Practices", Public
Health Service Publication #526.
SAMPLE PLOT PLAN
0 UJCLU
SUMMIT COUNTY DEPARTMENT OF ENVIRONMENTAL HEALTH
P. 0. Box 592 Phone 453-2561
Breckonridgo, Colorado 80424
APPLICATION FOR INDIVIDUAL SEWAGE DISPOSAL SYSTEM PERMIT - SUMMIT COUNTY
Name of Owner:
Phone
Address of Owner
Name of Applicant
Permit to be:
Location of Proposed:
Type of Structure:
Number of Bedrooms (
Water Supply:
Size of Lot :
( ) Picked Up Mailed to:
Street Address
Legal Description
( ) Single Family Dwelling I
), Lofts ( ), Garbage Disposals
( ) Private Well
( ) Owner
) Other
Phone
( ) Applicant
( ), Automatic Washing Machine ( )
( ) Public
_
An appropriate plot plan must accompany this application showing required information. See
attached sheet. An onsite inspection must be arranged with the Summit County Department of
Environmental Health (8:30 A.M. - 9:30 A.M.) after receipt of application, plot plan, and
percolation tests results if a Registered Professional Engineer has conducted the
required tests. PAYMENT CANNOT BE ACCEPTED WITH APPLICATION. Permit, upon approval of
this application may be obtained at the Summit County Department of Environmental Health,
or by mail, with payment of a $35.00 (Thirty Five Dollar) fee. Permit must be issued
before a building department permit can be obtained.
APPOINTMENT FOR FINAL INSPECTION MUST BE MADE PRIOR TO BACKFILLING BY CONTACTING THE
INSPECTING SANITARIAN (8:30 - 9:30 A.M.) REFER TO THE PERMIT NUMBER. NO ACCEPTANCF WILL
BE GIVEN ON ANY SYSTEM WITHOUT A FINAL INSPECTION.
Application for an individual sewage disposal system is hereby submitted. The individual
sewage disposal system will be constructed and installed in accordance with the regulations
governing individual sewage disposal system within Summit County, and will comply with the
Colorado Water Pollution Control Act of 1966 as amended. The undersigned acknowledges that
the above information is true and that false information will invalidate the application
or subsequent permit.
Signature of Applicant: Date: ___^
(This application becomes invalid 12 months from above date)
HEALTH DEPARTMENT USE ONLY
Percolation information
Tank Capacity
Absorption Area
Remarks
Gal. Minimum
Sq. Ft. Minimum
Permit No.
Fee Receipt
File
--
_
_
Application is:
Sanitarian
( ) Approved
Director/ Assistant Director
C ) Denied
Date:
Date:
(Health Department approval expires 12 months from the above date)
The above individual sewage disposal system was installed by^
and has been inspected for use by a representative of the Summit County Department of
Environmental Health. The owner assumes all responsibility in case of failure or
inadequacy of this sewage disposal system.
Completed as-built drawing on reverse side of this page will be made by the inspecting
sanitarian.
Date:
L97
C - 4
Page 7
Sanitarian
-------
PLOT PLAN
NAME:
ADDRESS
LOCATION OF PROPOSED SYSTEM:
STREET ADDRESS
LEGAL ADDRESS
PLOT PLAN MUST INCLUDE THE FOLLOWING INFORMATION: (LOCATF. BY MEASURED DISTANCES)
1. Property lines and dimensions.
2. Proposed and existing water wells on subject property and adjacent property.
3. Domestic water service lines.
4. Proposed and existing buildings, driveways and other structures.
5. Streams, lakes, ponds, irrigation ditches and other water courses.
6. Proposed and existing waste disposal facilities.
SUBMIT A REVISED PLOT PLAN PRIOR TO CONSTRUCTION IF INSTALLATION IS TO BE CHANGED
FROM ORIGINAL PLAN.
RESULTS OF PERCOLATION TEST
STREET ADDRESS OR LEGAL DESCRIPTION:
DATE OF TEST:
DIAMETER
LOCATION OF TEST HOLE:
TEST HOLE WAS PRE-SOAKED FROM:
DEPTH OF HOLE:
"TYPE OF SOIL
(TIME)
HOLE »1
TIME
HOLE #2
TO
MPI
(DATE)
WATER DEPTH
(TIME)
INCHES OF FALL
(DATE)
RATE
MPI
HOLE »3
MPI
PERCOLATION RATE:
REMARKS:
MPI
BY:
C - S
Page 8
Page 9
-------
ACCEPTABLE PERCOLATION TEST HOLE EXCAVATIONS
ACCEPTABLE ABSORBTION SYSTEM DESIGNS
Hand dug
or drilled test hole, 12"
maximum diameter
TYPICAL ABSORBTION SYSTEM CROSS SECTION
Backhoe
excavated portion
Hand dug or drilled portion,
IV minimum depth, 12" maximum
diameter
t
. - ,-h -
i 1
I
-
-x
I I
r " i
L- _ _
r-
I l
-------
1
ACCEPTABLE ABSORBTION SYSTEM DESIGNS
Perforated Pipe
I
SEPTIC TANK INSTALLATIONS
8" maximum ground cover
id
Two compartment tanks required after September 1, 1974
C - 7
ABSORBTION SYSTEM DESIGNS WHICH ARE MOT ACCEPTABLE
O Distribution Box -» Perforated Pipe
*
I _____ 1
\
' \
r
r i
L .
I J _ J _J
r
i ;
n
i
i,,
-V
t
^v
II!
-------
APPENDIX "D"
-------
PHOSPHORUS EFFLUENT LIMITATIONS FOR DOMESTIC
WASTEWATER DISCHARGES IN THE BLUE RW£R BASIN
I. Limitations Given in Water Quality Management Plan
The Water Quality Management Plan, Blue River Hydrologic Basin,
recommends a wasteload allocation of Phosphorus for domestic waste-
water discharges in the Blue River Basin. The purpose of this allo-
cation is to protect water quality in Dillon Reservoir and Green
Mountain Reservoir. The allocation is given in average pounds per
day of Phosphorus (as P) in Tables 18 and 19 of the Plan. These are
considered as annual average values. The Plan also recommends maximum
effluent concentrations and that the daily maximum discharge of
Phosphorus not exceed the average daily limitation by more than a
factor of 1.29. The Plan's recommended maximum pffluent concentrations
are based on the wastewater flow values (Table 9) used in allocating
the Phosphorus limitation for a particular portion of the Basin. The
factor of 1.29 is based on the seasonal variations in wastewater flows
at a resort area having similar use patterns. The maximum monthly flow
was 1.29 times the annual average flow.
II. Problems with Using Limitations as Given in Water Quality Manage-
ment Plan
When attempting to apply the Plan's recommended effluent limita-
tions on Phosphorus to NPDES permits, some questions arose as to the
reasonableness of some of the limitations as they were expressed in
the Plan. It is recognized that the average daily limitations were
based on available data and they will be used as the basis for the
Phosphorus limitations in the permits . The problems are with the
daily limitations, effluent concentrations, and the apparent lack of
adequate consideration for seasonal variation in flow.
The biggest problem was with the Plan's recommended limits for
daily maximum pounds per day. Since the 1.29 factor was based on a
maximum monthly flow, it most likely does not represent the maximum
daily flow that would occur during the year. Furthermore, such a
tight daily limitation does not take into consideration the normal
day-to-day variations in operational control. In retrospect, it could
be said that the factor of 1.29 should have been used as a monthly
average instead of a daily maximum. That also would have provided for
some seasonal variation.
It was not stated in the Plan whether the recommended effluent
concentrations were to be daily maximum, weekly average, or monthly
average. The wording "Maximum Effluent Concentration" implies daily
maximum, the recommended values for the discharges to Dillon Reservoir
and its tributaries ranged from 0.134 to 0.188 mg/1. These concentra-
tions are approaching the lower limits of practical removal technology
and therefore, could not be considered as reasonable daily maximum
concentrations.
P - 1
III. Recommended Phosphorus Limitations for Use in NPDES Permits for
Blue River Basin
After considerable discussion and some false starts, it is recommended
that the following limitations on Phosphorus (as P) be used in the
permits for the domestic wastewater discharges in the Blue River Basin:
A. Discharges Tributary to Dillon Reservoir and its Tributaries:
Annual Average - Ibs/day from wasteload allocation
30-day Average - 1.3 x Annual Average from wasteload
allocation - Ibs/day
30-day Average - 0.2 mg/1
Daily Maximum - 0.5 mg/1
B. Discharges to the Lower Blue River Basin - Below Dillon
Reservoir:
Annual Average - Ibs/day from wasteload allocation
30-day Average - 1.3 x Annual Average from wasteload
allocation - Ibs/day
30-day Average - 0.4 mg/1
Daily Maximum - 1.0 mg/1
The rationale for these limitations is given below.
Annual Average - Ibs/day: Based on wasteload allocation.
30-day Average - Ibs/day: The factor 1.3 is 1.29 rounded off
to the nearest tenth. This value
would give some allowance for seasonal
variation in flow as found at a
similar recreation-type area.
30-day Average Concentration - mg/1: The intent of this
concentration limitation is to
insure that the Phosphorus removal
facilities are designed, constructed,
and utilized to the degree of
technology that is called for in the
Water Quality Management Plan.
By having a concentration limita-
tion, it will not be possible to
slack off in the treatment
efficiency at those facilities where the
flows presently are significantly less
than used in the wasteload allocation.
The 0.2 mg/1 value was obtained by
rounding the values of 0.134-0.188 mg/1
from the Water Quality Management Plan
up to 0.2 mg/1. The 0.4 mg/1 value was
-------
similarly obtained by rounding
0.375 mg/1 up to 0.4 mg/1
Daily Maximum Concentration - rng/1: This limitation is based
on 2.5 times the 30-day Average
concentration. The intent is to
allow for the normal day-to-day
variations in operation, yet have a
limitation that requires a reasonable
degree of treatment at all times. A
properly desianed,constructed, and
operated, physical-chemical system
should provide a consistent degree
of treatment and not be as subject
to upsets as is a biological system.
The State of Colorado has indicated that it would consider requests
for seasonal allocation of the Phosphorus limitation If the permittee
can justify it. There are potential advantages and disadvantages to
this approach, but it seems worth trying.
cc: State of Colorado
D -
-------
APPENDIX "E"
-------
Par..
STP CO
EFFLUENT LIMITATIONS
A-BASIN
Page 2 of 14
Permit No. : CO-0023876
A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS - SEE ANY ADDITIONAL
REQUIREMENTS UNDER PART III.
1. Effluent Limitations
Effective immediately,
the quality of effluent discharged by the facility shall, as a
minimum, meet the limitations as set forth below:
Average Effluent Concentration
Parameter
- mg/1
Total Suspended Solids - mg/1
Fecal Col i forms - number/300 ml
Total Residual Chlorine - mg/1
Oil anci Grease - mg/1
pH - units
30 Consecutive
Day Period
30 a/
30 a/
200 c/
N/A
N/A
7 Consecutive
Day Period
45 b/
45 b/
400 c/
0.5 d/
10.0 d/
Shall remain between 6.0 and 9.0. d/
a/ This limitation shall be determined by the arithmetic mean of a minimum
of three (3) consecutive samples taken on separate weeks in a 30-day
period (minimum total of three (3) samples); not applicable to fecal
coliforms - see footnote c/.
b/ This limitation shall be determined by the arithmetic mean of a minimum
of three (3) consecutive samples taken on separate days in a 7-day period
(minimum total of three (3) samples); not applicable to fecal coliforms
- see footnote c/.
c/ Averages for fecal conforms shall be determined by the geometric mean of
a minimum of three (3) consecutive grab samples taken during separate weeks
in a 30-day period for the 30-day average, and during separate days in a
7-day period for the 7-day average, (minimum total of three (3) samples)
d/ Any single analysis and/or measurement beyond this limitation shall be
considered a violation of the conditions of this permit.
This limitation shall be determined by the analysis of a composite sample
composed of a minimum of four (4) grab samples collected at equally-spaced
two (?.) hour intervals, and proportioned according to flow.
F - J
-------
rt. J STP CO
Patje 3 of 14
Permit No.: CO-0023876
A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS - SEE ANY ADDITIONAL
REQUIREMENTS UNDER PART III.
1. Effluent Limitations
Effective as soon as reasonable and practical but no later than
July 1, 1977, the quality of effluent discharged by the facility
shall, as a minimum, meet the limitations as set forth below:
Average Effluent Concentration
30 Consecutive 7 Consecutive
Parameter Day Period Day Period
BOD5 - mg/1 30 a/ 45 b/
Total Suspended Solids - mg/1 30 a/ 45 b/
Fecal Conforms - number/100 ml 200 c/ 400 c/
Total Residual Chlorine - mg/1 N/A 0.05 d/
011 and Grease - mg/1 N/A 10.0 d/
Phosphate as P - Ibs/day (kg/day) 0.016(0.0073) e/
pN - units Shall remain between 6.0 and 9.0.d/
a/ This limitation shall be determined by the arithmetic mean of a minimum of
three (3) consecutive samples taken on separate weeks in a 30-day period
(minimum total of three (3) samples); not applicable to fecal conforms
- see footnote c/.
b/ This limitation shall be determined by the arithmetic mean of a minimum of
three (3) consecutive samples taken on separate days in a 7-day period
(minimum total of three (3) samples); not applicable to fecal conforms
- see footnote c/.
c/ Averages for fecal conforms shall be determined by the geometric mean of
a minimum of three (3) consecutive grab samples taken during separate weeks
1n a 30-day period for the 30-day average, and during separate days in a
7-day period for the 7-day average, (minimum total of three (3) samples)
d/ Any single analysis and/or measurement beyond this limitation shall be
considered a violation of the conditions of this permit.
e/ This limitation shall be determined by the analysis of a composite sample
composed of a minimum of four' (4) grab samples collected at equally-spaced
two (2) hour Intervals, and proportioned according to flow.
-------
m
o
E
m
i
1-4
O
a
a
ii
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i
EFFLUENT LIMITATIOHS - SEE ANY ADDITIONAL REQUIREMENTS UNDER PART III.
1. Effluent Limitations
Effective immediately and lasting through December 31, 1975, the quality
of effluent discharged by the facility shall, as a minimum, meet the limi
Effluent Characteristic
limitations as set forth belcw.
Weight
Concentration
Flow - i»3/Oay(KGD)
B005 - mg/1
Total Suspended Solids
Fecal Coliforms -
number/100 ml
Total Residual Chlorine -
mg/1
Total Phosphorus (as P)
Dissolved Aluminum
kg/day (ibs/day)
Annual Avg. h/ 30-day Avg. a/
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
mg/1
30-day Avq. a/
N/A
30
30
200 £/
N/A
N/A
N7A
rag/1
7-day Avq. b/
N/A
45
45
400 £/
N/A
N/A
N/A
mg/1
Daily Max. if
N/A
N/A
N/A
N/A
0.5
0.5
1.0
Oil and Grease shall not exceed 10 rag/1 In any grab sample nor shall there be a visible sheen. The effluent shall
be monitored weekly by visual observation.
-------
A. EFFLUENT LIMITATIONS - SEE ANY ADDITIONAL REQUIREMENTS UNDER PART III.
2. Effluent Limitations
Effective as soon as reasonable and practical but no later than January 1, 1976, the quality
of effluent discharged by the facility shall, as a minimum, meet the limitations as set forth below.
Effluent Characteristic
Flow - m3/Day(MGD)
BODj - mg/l
Total Suspended Solids
Fecal Col[forms -
number/100 ml
Total Residual Chlorine -
mg/l
Total Phosphorus (as P)
Dissolved Aluminum
Weight
kg/day (Ibs/day)
Annual Avg . h/ 30-day Avg. a/
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Concentration
mg/l mg/l
30-day Avg. a/ 7-day Avg. b/
N/A
30
30
200 £/
N/A
45
45
400 '£/
mg/l
Dally Max. d/
N/A
N/A
N/A
N/A
N/A
0.013(0.029)
N/A
N/A
0.017(.0377) J/
N/A
N/A
0.2
N/A
N/A
N/A
N/A
0.5
0.5
1.0
Oil and Grease shall not exceed 10 mg/1 In any grab sample nor shall there be a visible sheen. The effluent shall
be monitored weekly by visual observation.
E - H
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-o
1
CO
m
i
EFFLUENT LIMITATIONS - SEE ANY ADDITIONAL REQUIREMENTS UNDER PART III.
1. Effluent Limitations
effective immediately and lasting through June 30, 1977, the quality
of.effluent discharged by the facility shall, as a minimum, meet the limitations as set forth below.
Effluent Characteristic
Weight
kg/day (Ibs/day)
Annual Avg. h/ 30-day Avg. a/
Flow
3CDj
Total
Fecal
- r--,:ay(MGD)
- r.g/1
S-jsrsnded Solids
Co! T forms -
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Concentration
mg/1 mg/1
30-day Avg. a/ 7-day Avg. b/
N/A
30
30
200 c/
N/A
45
45
400 'c/
mg/1
Dally Max. d/
N/A
N/A
N/A
N/A
nunber/!00 ml
Total Residual Chlorine - N/A
ng/1
Tots! ?;-c3p:-crus (as P) N/A
Dissolved Aluminum N/A
N/A
N/A
N/A
N/A
0.5*
N/A
N/A
N/A
N/A
0.5
N/A
1.0
zo
O i-*
* This limitation shall not be applied if the average daily flow exceeds 250,000 gallons
per day and the ballast pond is full.
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to
CO
CO
Oil and Grease shall not exceed 10 mg/1 in any grab sample nor shall there be a visible sheen. The effluent shall
be r-onitcred daily by visual observation.
-------
A. EFFLUENT LIMITATION? - SEE ANY ADDITIONAL REQUIREMENTS UNDCH PART III.
2.- Effluent Limitations
Effective as soon r.o reasonable and practical but no later than July 1, 1977. the quality
of effluent dischargee by the facility shall, as a minimum, meet the limitations as set forth below.
Effluent Characteristic
Flow - m3/Day(MGD)
BODj - rcg/1
Total Suspended Solids
Fecal Col I forms -
number/100 ml
Total Residual Chlorine -
mg/1
Total Phosphorus (as P) J./
Dissolved Aluminum
Weight
kg/day (Ibs/day)
A.:.:.-! Avg. h/ 30-day Avg. a/
::/A
N/A
-7 .A
M/A
N/A
N/A
N/A
N/A
Concentration
mg/1 mg/V
30-day Avg. a/ 7-day Avg. b/
N/A
30
30
200 c/
N/A
45
45
400 c/
mg/1
Dally Max. d/
N/A
N/A
N/A
N/A
N/A
0.250(0.629)
W/A
N/A
0.392<0.818) ij
N/A
N/A
N/A
0.5
0.2
N/A
N/A
N/A
0.5
1.0
(DPP
3 W 4
3 fi> rt
!-"
(4- B»+ ^
Oil and Grease shall not exceed 10 ng/1 in any grab sample nor shall there be a visible sheen. The effluent shall
be monitored daily by visual observation.
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cn
E - 6
-------
o
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m
, EFFLUENT LIMITATIONS - SEE ANY ADDITIONAL BEaUIREMENTS UNDER PART III.
"^ 1. Effluent Limitations
Effective iumediately, and lasting through June 30, 1977, the quality
of effluent discharged by the facility shall, as a minimum, meet the limitations as set forth below.
' r
Effluent Characteristic
Flow - mVuayCMGD)
BODj - mg/1
Total Suspended Solids
Fecal Coliforms -
number/100 ml
Total Residual Chlorine - N/A N/A N/A N/A 0.1
ag/1
Total Phosphorus (as P) 0.83(1.82) 1.08(2.37) i/ 0.33 N/A 0.83
Dissolved Aluminum- 7 Day Av. 3-7(8.1) b/ N/A N/A N/A
Weight
kg/day(lbs/day)
Annual Avg. h/ 30-day Avg. a/
N/A
N/A
N/A
N/A
N/A.
N/A
N/A
N/A
Concentration
mg/1 .mg/1
30-day Ava. a/ 7-day Avg. b/
N/A
5-0
5.0
N/A
N/A
10.0
10.0
5,000 c/
mg/1
Daily Max. d/
N/A
N/A
N/A
N/A
Oil anc Grease shall not exceed 10 mg/1 in any grab sample nor shall there be a visible sheen. The effluent shall \r\
be nonitored daily by visual observation. \£
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Pa r i I
P;i 3 of 17
Permit No. CO-002I539
A.
REQUIREHEHTS -
i'/il'J i
I'.ujc 'i of 17
Permit Ho.: co-0021539
ANY
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3. Future Effluent Limitations in Addition to Limitations in Part I, A. 2
Tim Act requires that effluent limitations based i/pon secondary
treatment, water quality standards, or state effluent standards
Whichever in rare stringent, shall be achieved by all publicly-
owned treatment works. It has been determined that in order to
prevent violation of the State of Colorado Water Quality Standards
end to most the secondary treatment requirements, and Colorado
effluent standards, the following effluent limitations must be
achieved.
In addition to the specified limitations, the discharge shall
contain no visible floating solids and/or, visible Oil and Grease.
1
fe
£
t£
".-
ol
Parameter
30 Consecutivi; 7 Consecutive
_.. Day Period Day Period Instantaneous
Ammonia (as N) - Kg/day(Ibs/day)
N/A
36(79)
N/A
fD .
u .
.- nj
o -
c .
(D U
c
10 rc
& §
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1 EFFLUENT LIMITATIONS - SEE ANY ADDITIONAL REQUIREMENTS UNDER PART III.
to
1. Effluent Limitations
Effective immediately and lasting through October 31, 1976, the quality
of effluent discharged by the facility shall, as a minimum, meet the limitations as set forth below.
Effluent Characteristic
Flow - «3/Day(MGO)
SODj - mg/1
Total Suspended Solids
Fecal Coliforms -
nuirber/100 ml
Total Residual Chlorine -
ng/1
Total Phosphorus (as P)
Dissolved Aluminum
Weight
kg/day (Ibs/day)
Annual Avg. h/ 30-day Avg. a/
N/A
N/A
N/A
N/A
N/A
N/A.
N/A
N/A
Concentration
mg/1 mg/1
30-day Avg. a/ _J-day Avg. b/
N/A
30
30
200 oj
N/A
45
45
400 £/
mg/1
Daily Max. d/
N/A
N/A
N/A
N/A
N/A
.104(.23>
N/A
N/A
.136(.299)
N/A
N/A
0.2
N/A
N/A
N/A
N/A
0.5
0.5
1.0
c "or
Ct tO*
O <->
O>
i
o
o
to
Oil and Grease shall not exceed 10 mg/1 in any grab sample nor shall there be a visible sheen. The effluent shall
be monitored daily by visual observation.
-------
A. EFFLUENT LIMITATIONS - SEE ANY ADDITIONAL REQUIREMENTS UNDER PART III.
1. Effluent Limitations
Effective as soon as reasonable and practical but no later than November 1, 1976, the quality
of effluent discharged by the facility shall, as a minimum, meet the limitations as set forth below.
Effluent Characteristic
Flow - mVOay(MGD)
BODj - mg/1
Total Suspended Solids
Fecal Col I forms -
number/100 ml
Total Residual Chlorine -
mg/1
Total Phosphorus (as P)
Dissolved Aluminum
Weight
kg/day (Ibs/day)
Annual Avg. h/ 30-day Avq. a/
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Concentration
mg/1 mg/1
30-day Avg. a/ 7-day Avq. b/
N/A
30
30
200 c/
N/A
45
45
400 c/
mg/1
Daily Max. d/
N/A
N/A
N/A
N/A
N/A
.104(.23)
N/A
N/A
.136( .299) j./
N/A
N/A
0.2
N/A
N/A
N/A
N/A
0.1
0.5
1.0
a v
i rc
3 n
O
O
I
O
O
to
M
en
(O
oo
bn,l Sh?'l "Ot eXCCed 10 "I9/1 In any srab sample nor sha" there be a visible sheen. The effluent shall
be monitored daily by visual observation.
E - 10
-------
TO
O
EFFLUEHT LIMITATIONS - SEE ANY ADDITIONAL REQUIREMENTS UNDER PART in.
i'
!. Effluent Limitations
Effective immediately and lasting through June 30, 1977, or two (2) months after completion
of the Advanced Wastewater Treatment Unit, the quality
of effluent discharged by the facility shall, as a minimum, meet the limitations as set forth below.
Effluent Characteristic
Weight
kg/day (tbs /day)
Annual Avg, h/ 30-day Avg. a/
Flow - ni3/Day{MSQ)
BODc, - irg/1
Total Suspended Solids
Fecal Col i forms -
ntnber/100 ml
Total Residual Chlorine -
ng/1
Total Phosphorus (as P)
Dissolved Aluminum
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A .
N/A
N/A
N/A
N/A
N/A
Concentration
mg/1 mg/1
30-day Avg. a/ 7-day Avg. b/
N/A
30
30
N/A
N/A
N/A
N/A
N/A
45
45
5000 c/
N/A
N/A
N/A
ms/1
Daily Max. d/
N/A
N/A
N/A
N/A
0.1
N/A
i.o i/
"3 "
0 t>
3 O
O
2:0
O >-!
o
o
i
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to
o
Oil and Grease shall not exceed 10 ng/1 in any grab sample nor shall there be a visible sheen. The effluent shall
be imnicored daily by visual observation.
-------
A. EFFLUENT LIMITATIONS - StE ANY ADDITIONAL REQUIREMENTS UNDER PART III.
1. Effluent Limitations- Effective as soon as reasonable and practical, but no later than
July 1, 1977, or two months after completion of the Advanced Wastewater Treatment
System, whichever is first, the quality
of effluent discharged by the facility shall, as a minimum, meet the limitations as set forth below.
Effluent Characteristic
yeight Concentration
kg/day (Ibs/day) mg/1 mg/1 mg/1
Annual Ava. h/ 30-dav Avq. a/ 30-day Avg. a/ 7-day Avg. b/ Dally M^x. d/
Flow - m3/Day(KGD)
BODj - mg/1
Total Suspended Solids
Fecal Col iforre -
number/ 100 ml
Total Residual Chlorine -
ng/1
Total Phosphorus (as P)
Dissolved Aluminum
N/A
N/A
N/A
N/A
N/A
0.35(0.77)
N/A
N/A N/A
N/A 30
N/A 30
N/A 200 C/
N/A N/A
0.454(1.0) y 0.2
N/A N/A
N/A N/A
45 N/A
45 N/A
400 c/ N/A
N/A 0.03
N/A 0.5
N/A 1.0 ^
o .
H-
r*
2
r:
o
i
o
o
to
o
Oil and Grease shall not exceed 10 ng/1 In any grab sample nor shall there be a visible sheen. The effluent shell
be monitored daily by visual observation.
E - 1.?
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APPENDIX "F"
-------
The waste load allocations developed as part of the 303(e) plan for
the Blue River Basin can be viewed as effectively limiting population
growth within certain areas of the basin that are critical from a water
quality standpoint. This can be exemplified by the waste load allocations
for phosphorus which were designed to protect the Snake River Arm of
Dillon Reservoir.
The waste load allocation developed as part of the plan calls for an
average dally discharge of phosphorus from point sources reaching the
Snake River Arm not to exceed 0.70 Ib/day. Assuming that the limit of
present technology 1s for 993! removal of phosphorus from ordinary strength
domestic sewage, the maximum population equivalent which can be permitted
to hook onto municipal systems 1s limited by the maximum treatment efficiency,
the phosphorus generated by a population equivalent and the waste load alloca-
tion. Since 1!^ of the phosphorus generated by municipal wastewater would
still be discharged to the reservoir and the average person general 0.006 Ib/day,
the average dally population would be limited to approximately 12,000 persons.
The waste load allocation limitations were subsequently Issued as a
part of the permit limitations for discharge of treated municipal waste
discharged to the Snake River Basin as part of the National Pollutant Dis-
charge Elimination System (NPDES). Violation of the poundage limitation
of phosphorus discharged from treatment works can result 1n the Imposition
of fines and/or a ban on new taps to the sewage system enforceable under the
provisions of Section 402(h) of the Federal Water Pollution Control Act
Amendments. Hence, enforcement action taken by the Federal or State pol-
lution control agency can effectively limit the maximum number of taps con-
nected to a wastewater treatment facility.
r -
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APPENDIX "G"
-------
A. DETAILED DESCRIPTION OF ALTERNATE STRATEGIES
(Note: Flow capacities are projected to 1977.)
Alternative 1.
(a) Advanced wastewater treatment facility at Swan Mountain
Road to serve entire Upper Blue River Basin (2MGD).
(b) Advanced wastewater treatment facility at the confluence
of. Dillon Reservoir and Snake River to serve the entire
Snake River Basin (1.1 MGD).
(c) Advanced wastewater treatment facility at Frisco to serve
entire Tenmile Creek Basin (1.2 MGD).
(d) Advanced wastewater treatment facility at the existing
Silverthorne site to serve all areas upstream to Dillon
Reservoir (1.7 MGD).
(e) Advanced wastewater treatment facility to serve the area
between Green Mountain Reservoir and the Silverthorne
facility (0.3 MGD).
(f) Secondary treatment facility to serve the area adjacent
to Green Mountain Reservoir and discharging downstream
from the reservoir (0.1 MGD).
(g) Secondary treatment facilities to serve the tributary
area between Green Mountain Reservoir and the Colorado
River (0.05 MGD).
Alternative 2.
(a) Secondary treatment facility at Swan Mountain Road to
serve the entire Upper Blue River Basin with a 11ft
station and force main to transport the effluent to
the Frisco area (2 MGD).
A 1
- 1
(b) Secondary treatment facility at the confluence of Dillon Reser-
voir and the Snake River to serve the entire Snake River Basin
with a lift station and force r.iain to the Silverthorne area (1.1
MGD).
(c) Secondary treatment facility at Frisco to serve the entire Ten-
mile Creek Casin with a lift station and force main to trans-
port the effluent from the Upper 131 un River Basin and the Ten-
mile Creek Basin to the Silverthorne area (Treat 1.2 MGD; Pump
3.2 MGD).
(d) Advanced wastewater treatment facility below Dillon Reservoir
at. the existing Silverthorne sit? to receive secondary efflu-
ent from the Upper Blue River Basin, the Snake River Basin
and the Tenmile Creek Basin as will as raw effluent from the
tributary area upstream from the Silverthorne plant to Dillon
Reservoir (Total flow of 6.0 MGD).
(e) Advanced wastev.-ater treatment facility to serve the area be-
tween Green Mountain Reservoir pud the Silverthorne facility
(0.3 MCD).
(f) Secondary treatment facility to serve the area adjacent to
Green Mountain Reservoir and discharging downstream from the
reservoir (0.1 MGD).
(g) Secondary treatment facilities to serve the tributary area be-
tween Green Mountain Reservoir and the Colorado River (0.05 MGD).
Alternative 3.
(a) Secondary treatment facility at Swan Mountain Rood to serve
the entire Upper Blue River Basin with a force main and lift
station to transport the effluent to the Frisco area (2 MGD).
A 2
-------
(b) Secondary treatment facility at the confluence of Dillon
Reservoir and the Snake River to serve the Snake River
Basin upstream to the vicinity of the confluence of the
North Fork and ma1nstern of the Snake River (1.0 MGD).
(c) Advanced wastewater treatment facility to serve the Arapahoe
Basin area (0.05 MGD).
(d) Secondary treatment facility at Frisco to serve the Tenmile
Creek Basin upstream to Wheeler Junction (1.0 MGD).
(e) Advanced wastewater treatment facility at Wheeler Junction (0.2 M
(f) Advanced wastewater treatment facility below Dillon Reser-
voir at the existing Silverthorne site to receive secondary
effluent from the Upper Blue River Basin, the Snake River
Basin and the Tenmile Creek Basin as well as raw effluent
from the tributary area upstream from Silverthorne plant to
Dillon Reservoir (5.7 MGD).
(g) Advanced wastewater treatment facility to serve the area
between Green Mountain Reservoir and the Silverthorne facility (0
(h) Secondary treatment facility to serve the area adjacent to
Green Mountain Reservoir and discharging downstream from the
reservoir (0.1 MGO).
(1) Secondary treatment facilities to serve the tributary area
between Green Mountain Reservoir and the Colorado River (0.05 MGD
Alternative 4.
(a) Secondary treatment facility at Swan Mountain Road to serve
the entire Upper Blue River Basin with a force main and lift
station to transport the effluent to the Frisco area (2 MGD).
A3 G -2
(b) Secondary treatment facility at the confluence of
Dillon Reservoir and the Snake River to serve the
Snake River Basin upstream to the vicinity of the
confluence of the North Fork and mainstem of the
Snake River (1.0 MGD).
(c) Advanced wastewater treatment facility to serve the
Arapahoe Basin area (0.05 MGD).
(d) Secondary treatment facility at Frisco to serve the
Tenmile Creek Basin upstream to Wheeler Junction (1.0 MGD).
(e) Advanced wastewater treatment facility at Wheeler
Junction (0.2 MGD).
(f) Advanced wastewater treatment facility upstream from
Green Mountain Reservoir to receive secondary effluent
from the tributary basins of Dillon Reservoir and re-
ceive all wastes from the tributary area between
Green Mountain Reservoir and Dillon Reservoir (6.0 MGD).
(g) Secondary treatment facility to serve the area adjacent
to Green Mountain Reservoir and discharging downstream
from the reservoir (0.1 MGD).
(h) Secondary treatment facilities to serve the tributary
area between Green Mountain Reservoir and the Colorado
River (0.05 MGD).
Alternative 5.
(a) Advanced wastewater treatment facility at Swan Mountain
Road to serve the entire Upper Blue River Basin (2 MGD).
(b) Secondary treatment facility at the confluence of Dillon
Reservoir and the Snake River to serve the entire Snake
River Basin with a lift station and force main to the
S11 vert home area (1.1 MGD).
n *f
-------
(c) Secondary treatment facility at Frisco to serve the entire
Tenmlle Creek Basin with a lift station and force main to
transport effluent to the Sllverthorne area (1.2 MGD).
(d) Advanced wastewater treatment facility below Dillon Reser-
voir at the existing Sllverthorne site to receive secondary
effluent from the Snake River Basin and the Tenmlle Creek
Basin as well as raw effluent from the tributary area up-
stream from the Sllverthorne plant to Dillon Reservoir (4.0 MGD).
(e) Advanced wastewater treatment facility to serve the area
between Green Mountain Reservoir and the Sllverthorne facility (0.3 MG
(f) Secondary treatment facility to serve the area adjacent to
Green Mountain Reservoir discharging downstream from the
reservoir (0.1 MGD).
(g) Secondary treatment facility to serve the tributary area
between Green Mountain Reservoir and the Colorado River (0.05 MGD).
Alternative 6.
(a) Advanced wastewater treatment facility at Swan Mountain
Road to serve the entire Upper Blue Rtver Basin (2.0 MGD).
(b) Advanced wastewater treatment facility at the confluence
of Dillon Reservoir and the Snake River to serve the Snake
River Basin upstream to approximately the confluence of the
North Fork and the malnstem of the Snake River (1.0 MGD).
(c) Advanced wastewater treatment facility at Arapahoe Basin (0.05 MGD).
(d) Advanced wastewater treatment facility at Frisco to serve
the Tenmlle Creek Basin upstream to Wheeler Junction (1.0 MGD).
(e) Advanced wastewater treatment facility at Wheeler Junction (0.2 MGD).
(f) Advanced wastewater treatment facility at the existing
Silverthorne site to serve all areas upstream to Dillon
Reservoir (1.7 MGD).
(gj Advanced wastewater treatment facility to serve the area
between Green Mountain Reservoir and the Silverthorne
facility (0.3 MGD).
(h) Secondary treatment facility to serve the area adjacent
to Green Mountain Reservoir, discharging downstream from
the reservoir (0.1 MGD).
(i) Secondary treatment facilities to serve the area tributary
between Green Mountain Reservoir and the Colorado River (0.05 MGD).
A 5
G -3
A 6
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