EPA 908/5-81-OOIA
January, 1981
Region 8
1860 Lincoln Street
Denver, Colorado 80295
United States
Environmental Protection
Agency
&ERA Environmental draft
Impact
Statement
Hermosa
West Animas
Junction
Creek
Florida Road
Lighlner
Creek
DURANGO
iGrandview / Loma Linda
Wastewater Management Plan for the
Durango Area, La Plata County, Colorado
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EPA - 908/5-81-001A
DRAFT' ENVIRONMENTAL IMPACT STATEMENT
WASTEWATER MANAGEMENT PLAN FOR THE
DURANGO AREA, LA PLATA COUNTY, COLORADO
Prepared by
U.S. Environmental Protection Agency
Region VIII
1860 Lincoln Street
Denver, Colorado 80295
Approved by
^lliams
Administrate
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DISCLAIMER
This report has been reviewed by the EPA, Region VIII, Water
Division and approved for publication. Mention of trade names
or commercial products does not constitute endorsement or recommendation
for use.
DOCUMENT AVAILABILITY
This document is available in limited quantities through the
D. S. Environmental Protection Agency, Environmental Evaluation
Branch, 1860 Lincoln St., Denver, Colorado 80295. This document
is also available to the public through the National Technical
Information Service, Springfield, Virginia 22161.
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SUMMARY SHEET
ENVIRONMENTAL IMPACT STATEMENT
WASTEWATER MANAGEMENT PLAN FOR THE
DURANGO AREA, LA PLATA COUNTY, COLORADO
Prepared by the U. S. Environmental Protection Agency, Rocky Mountain
Prairie Region, Region VIII, Denver, Colorado, with assistance from
Engineering-Science, Inc., Denver, Colorado, Cap Allen Engineering,
Durango, Colorado, and Gruen, Gruen + Associates, San Francisco,
California.
A. Type of Action: (X) Draft EIS
C ) Final EIS
B. Brief Description of the Proposal
The Region VIII Administrator of the U. S. Environmental Protection
Agency (EPA) is considering approval of Federal matching funds for
wastewater treatment facilities for the City of Durango, Colorado, through
Title II of the Federal Water Pollution Control Act Amendments of 1972
(PL 92-500), as amended in the Clean Water Act of 1977 (PL 95-217).
Eligibility requirements and procedures necessary to qualify for a grant
are set forth in AO CFR, Part 35, Construction Grants for Wastewater
Treatment Works. The Federal share will be 75 percent of the total cost
found to be eligible.
The purpose of this environmental impact statement is to present
an evaluation of the environmental impacts of a plan submitted by the City
of Durango and La Plata County proposing to construct wastewater collection
and treatment systems in portions of the 201 Study Area that are not pre-
sently being served by the City of Durango1s wastewater treatment system.
C. Lead Agency, Project Officer Contact and Address
The U. S. Environmental Protection Agency is the lead agency in a
joint effort with the State of Colorado, La Plata County, and the City
of Durango, Colorado, to approve plans, necessary permits, and finance or
award grants in order to implement .this proposal. Mr. John M. Brink,
U. S. Environmental Protection Agency, Region VIII is the designated
project officer.
Requests for free copies of this document should be addressed to:
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Mr. John M. Brink, Project Officer
U.S. Environmental Protection Agency
Region VIII
1860 Lincoln Street
Denver, Colorado 80295
or call C303) 837-4831.
D. Abstract of the Proposed Action
Environmental affects of wastewater management were considered for
six areas outside of the Durango City limits in La Plata County, Colo-
rado. Three basic wastewater management alternatives were proposed for
each Study Area: (1) No Action, (.2) Formation of a Maintenance District,
and (3) Sewers, either with a local treatment facility or with connection
to the City of Durango's system. Environmental impacts of the No Action
and Maintenance District alternatives include possible degradation of
water quality, potential public health threats, and septage and sludge
disposal. While it would reduce these impacts and save electrical
energy, the sewer alternative might lead to increased growth rates, strip
development along the sewer lines, and increased population density. The
Maintenance District and sewer alternatives would also impose substantial
financial impacts on residents, particularly those with properly opera-
ting existing systems. Connection with the City of Durango's system could
lead to annexation under implied consent rules. No Action was recommen-
ded for the West Animas and Florida Road Study Areas and for portions of
the Junction Creek and Lightner Creek Study Areas. Interceptors to the
City of Durango system were, recommended for the remainder of the Junction
Creek and Lightner Creek areas. Local sewage treatment plants with
sewers were recommended for the Hermosa and Grandview/Loma Linda areas.
E. Date filed with EPA and listed in the Federal Register; 0 Q ^0^
ii
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TABLE OF CONTENTS
Page
SUMMARY SHEET i
ABSTRACT ii
LIST OF FIGURES viti
LIST OF TABLES xi
CHAPTER 1 SUMMARY 1
CHAPTER 2 PURPOSE AND NEED A
CHAPTER 3 DESCRIPTION OF ALTERNATIVES 19
PREVIOUSLY RECOMMENDED ALTERNATIVE 19
ALTERNATIVES CONSIDERED IN FACILITIES PLAN UPDATE 19
Hermosa 22
Alternative 1 - Formation of Maintenance District 23
Alternative 2 - Collection and Interceptor Lines
to Durango 23
Alternative 3 - Central Wastewater Treatment
Facility 23
Alternative 4 - No Action 25
Alternative 5 - Service Area Extension 25
Junction Creek 21
Alternative 1 - Collection and Interceptor Lines
to Durango 27
Alternative 2 - Collection and Interceptor Lines
to West Animas Sanitation District via Spring
Creek 27
Alternative 3 - Formation of a Maintenance District 29
Alternative 4 - Central Wastewater Treatment
Facility 29
Alternative 5 - Short Interceptor 29
Alternative 6 - No Action 29
iii
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TABLE OF CONTENTS (continued)
Page
Lightner Creek 29
Alternative 1 - Collection and Interceptor Line
to Durango 31
Alternative 2 - Formation of a Maintenance District 32
Alternative 3 - Central Wastewater Treatment
Facility 32
Alternative 4 - No Action 32
Grandview/Loma Linda 35
Alternative 1 - Collection and Interception Line
to Durango 35
Alternative 2 - Central Wastewater Treatment
Facility - Loma Linda and Falfa Areas 37
Alternative 3 - Central Wastewater Treatment
Facility - Grandview and Pinon Acres Area 37
Alternative 4 - Formation of a Maintenance District 37
Alternative 5 - Interceptor Line to Animas Air Park 41
Alternative 6 - No Action 41
Florida Road 41
Alternative 1 - Collection and Interceptor Lines
to Durango 41
Alternative 2 - Central Wastewater Treatment
Facility 43
Alternative 3 - Short Interceptor to Durango 43
Alternative 4 — Formation of a Maintenance District 43
Alternative 5 - No Action 43
West Animas 43
Alternative 1 - Collection and Interceptor Lines
to Durango 44
Alternative 2 - Central Wastewater Treatment
Facility 44
Alternative 3 - Formation of a Maintenance District 44
Alternative 4 - No Action 44
PROJECT IMPLEMENTATION 46
LOCAL REGULATORY FRAMEWORK 46
USER COSTS *8
RECREATIONAL USE *8
Staging of Construction 49
Implementation Schedule 50
CHAPTER 4 DESCRIPTION OF THE AFFECTED ENVIRONMENT 51
TOPOGRAPHY 51
GEOLOGY 52
iv
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TABLE OF CONTENTS (continued)
Page
GEOLOGIC HAZARDS 53
SOILS 53
WATER RESOURCES 63
Surface Water Hydrology 63
Surface Water Quality 63
Ground Water Hydrology 70
Ground Water Quality 70
BIOLOGICAL RESOURCES 71
Vegetation 71
Wildlife 71
Aquatic Life 77
Threatened and Endangered Species 81
METEOROLOGY AND AIR QUALITY 82
Meteorology 82
Air Quality 83
ENERGY RESOURCES 83
TRANSPORTATION 84
LAND USE PLANNING CONSIDERATIONS 84
Hermosa 85
Junction Creek 85
Lightner Creek 85
Grandvlew-Loma Linda 85
Florida Road 91
West Animas 91
Other Land Use Planning Considerations 91
EXISTING AND PROJECTED POPULATIONS 92
Existing Conditions 92
SOCIOECONOMIC CONSIDERATIONS 96
v
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TABLE OF CONTENTS (continued)
Page
CULTURAL RESOURCES 99
CHAPTER 5 ENVIRONMENTAL CONSEQUENCES 100
WASTEWATER MANAGEMENT PLANS 101
No Action 101
Formation of Maintenance District 103
Sewers 105
HERMOSA 109
Recommended Alternative 109
Other Alternatives 116
JUNCTION CREEK 116
Recommended Alternative 116
Other Alternatives 120
LIGHTNER CREEK 124
Recommended Alternative 124
Other Alternatives 132
GRAND/LOMA LINDA ' 132
Recommended Alternative 132
Other Alternatives 139
FLORIDA ROAD 139
Recommended Alternative 139
Other Alternatives 140
WEST ANIMAS 140
Recommended Alternative 140
Other Alternatives 144
THE RELATIONSHIP BETWEEN LOCAL SHORT-TERM USES OF MAN'S
ENVIRONMENT AND THE MAINTENANCE AND ENHANCEMENT OF
LONG-TERM PRODUCTIVITY 144
ANY SIGNIFICANT IRREVERSIBLE ENVIRONMENTAL CHANGES
WHICH WOULD BE INVOLVED IN THE PROPOSED ACTIONS
SHOULD THEY BE IMPLEMENTED 149
vi
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TABLE OF CONTENTS (continued)
Page
CHAPTER 6 PUBLIC PARTICIPATION 150
CHAPTER 7 LIST OF PREPARERS 151
REFERENCES
GLOSSARY
vii
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LIST OF FIGURES
2.1 201/EIS Study Area
2.2 Hermosa Study Area
2.3 Junction Creek and West Animas Study Areas
2.4 Lightner Creek Study Area
2.5 Grandview/Loma Linda Study Area
2.6 Florida Road Study Area
2.7 Multiple Input Wastewater Facilities
2.8 Individual On-Site Disposal Systems in the
Hermosa Area
2.9 Individual On-Site Disposal Systems in the
Junction Creek and West Animas Areas
2.10 Individual On-Site_Disposal Systems in the
Lightner Creek Area
2.11 Individual On-Site Disposal Systems in the
Grandview/Loma Linda Area
2.12 Individual On-Site Disposal Systems in the
Florida Road Area
3.1 Original Recommended Facilities for Outlying
Areas
3.2 Proposed Sewer Lines for Alternatives 2 and 5
in the Hermosa Area
3.3 Hermosa System
3.4 Proposed Sewer Alignment for Alternatives 1 and 2
and Proposed Treatment Facility Location for
Alternative 4 in the Junction Creek Area
3.5 Junction Creek Interceptor
3.6 Lightner Creek Interceptor
3.7 Proposed Sewer Alignment for Alternatives 1 and 3,
and proposed Facility Location for Alternative 3
in the Lightner Creek Area
3.8 Various Proposed Pipeline Configurations for Alternatives
1 and 5 in the Grandview/Loma Linda Area
3.9 Loma Linda System
3.10 Grandview System
3.11 Pipeline Configuration for Alternative Grandview
System
viii
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LIST OF FIGURES (continued)
3.12 Proposed Sewer Lines for Alternatives 1, 2, and 3,
and Alternative 2 Treatment Plant Location in the
Florida Road Area
3.13 Proposed Sewer Line for Alternative 1, and Alternative
2 Treatment Plant Location in the West Animas Area
4.1 Areas Potentially Constrained for Development by
Geologic Hazards - Hermosa Study Area
4.2 Areas Potentially Constrained for Development by
Geologic Hazards - Junction Creek Study Area
4.3 Areas Potentially Constrained for Development by
Geologic Hazards - Lightner Creek/Durango West
Study Area
4.4 Areas Potentially Constrained for Development by
Geologic Hazards - Grandview/Loma Linda Study Area
4.5 Areas Potentially Constrained for Development by
Geologic Hazards - Florida Road Study Area
4.6 Areas Potentially Constrained for Development by
^Geologic Hazards - West Animas Study Area
4.7 One Hundred Year Floodplain in the Hermosa Study Area
4.8 One Hundred Year Floodplain in the Junction Creek
Study Area
4.9 One Hundred Year Floodplain in the Lightner Creek
Study Area
4.10 One Hundred Year Floodplain in the Grandview/Loma
Linda Study Area
4.H One Hundred Year Floodplain in the West Animas Study
Area
4.12 Locations of Wetlands and Riparian Areas
4.13 Durango, Colorado Mule Deer Habitat
4.14 Durango, Colorado Elk Habitat
4.15 Durango, Colorado Bighorn Sheep Habitat
4.16 Durango, Colorado Osprey and Peregrine Falcon Habitat
4.17 Durango, Colorado Bald Eagle Habitat
4.18 Durango, Colorado Golden Eagle Habitat
4.19 Desired Growth Patterns in the Hermosa Area
4.20 Desired Growth Patterns in the Junction Creek and
West Animas Areas
4.21 Desired Growth Patterns in the Lightner Creek/Durango
West Area
ix
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4.22 Desired
Linda
4.23 Desired
LIST OF FIGURES (continued)
Growth Patterns in the Grandview/Loma
Study Area
Growth Patterns in the Florida Road Area
x
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LIST OF TABLES
3.1 Summary of Original Recommended
Alternatives for Outlying Areas
4.1 Soil Limitations and Development
Capabilities
4.2 Recent Population Growth in La Plata
County and Durango
4.3 Population Estimates of the Study Areas
4.4 Projected Population Increases for
Durango 201 Study Areas
4.5 Comparative Sample Land Prices in the
EIS Study Areas
4.6 Existing and Proposed Major Developments
in the Study Areas
5.1 Sanitary Survey Results
5.2 Potential Beneficial Impacts and Issues
Associated with Recommended Alternative
for Hermosa Area
5.3 Potential Adverse Impacts and Issues
Associated with Recommended Alternative
for Hermosa Area
5.4 Possible Mitigation Measures for Potential
Adverse Impacts Associated with.Recommended
Alternative for Hermosa Area
5.5 Potential Impacts Associated with Alterna-
tives to the Recommended Plan for the
Hermosa Area
5.6 Potential Beneficial Impacts and Issues
Associated with the Recommended Alterna-
tive for Junction Creek Area
5.7 Potential Adverse Impacts and Issues Assoc-
iated with Recommended Alternative for
Junction Creek Area
5.8 Possible Mitigation Measures for Potential
Adverse Impacts Associated with Recommen-
ded Alternative for Junction Creek Area
5.9 Potential Impacts Associated with Alter-
natives to the Recommended Plan for the
Junction Creek Area
5.10 Potential Beneficial Impacts, Adverse Im-
pacts, Issues, and Possible Mitigation
Measures Associated with Recommended
Alternatives for Lightner Creek Area
5.11 Potential Impacts Associated with Alterna-
tives to Recommended Plan for the Lightner
Creek Area
5.12 Potential Beneficial Impacts and Issues
Associated with Recommended Alternatives
for Grandview/Loma Linda Area
xi
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5.13 Potential Adverse Impacts and Issues
Associated with Recommended Alterna-
tives for Granview/Loma Linda Area
5.14 Possible Mitigation Measures for Potential
Adverse Impacts Associated with Recom-
mended Alternatives for Grandview/Loma
Linda Area
5.15 Potential Impacts Associated with Alterna-
tives to the Recommended Plans for the
Grandview/Loma Linda Area
5.16 Potential Impacts Associated with Alterna-
tives to the Recommended Plan for Florida
Road Area
5.17 Potential Impacts Associated with Alterna-
tives to the Recommended Plan for West
Animas Area
xii
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CHAPTER 1
SUMMARY
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CHAPTER 1
SUMMARY
In 1978 a Wastewater Treatment Facilities Plan (201 Plan) for the
Durango area in La Plata County, Colorado was submitted to EPA for
approval. The plan recommended construction of 28 miles of interceptor
sewers into presently unsewered areas outside the Durango City limits.
The sewering plan was designed to eliminate several privately owned sewage
treatment plants and septic tank systems that were thought to be polluting
the.Animas River and its tributaries. There were a number of potentially
adverse environmental impacts associated with the recommended alternative,
and EPA decided an Environmental Impact Statement was required to assess
these consequences and to explore alternatives of solving these problems.
Subsequently, an amended Facilities Plan was prepared. The amended plan ad-
dressed wastewater management needs in six areas outside of the Durango
City limits.
All of the six areas of concern are presently unsewered. A total of
46 privately owned multiple customer facilities provide much of the wastewater
treatment for the six areas. The remaining wastewater is treated on-
site, with systems ranging from septic tanks with leach fields to aerated
lagoons to evapotranspiration ponds. A recent sanitary survey indicated
that many of the package plants and some of the on-site systems have
experienced failures in the past, are currently not providing adequate
treatment of wastewater, and/or are expected to experience failures in
the near future.
Three basic wastewater management alternatives were proposed for
each Study Area: (1) No Action, (2) Formation of a Maintenance District,
and (3) Sewers, either with a local treatment facility or with connection
to the City of Durango's system. Subalternatives of the sewering option
in each Study Area included providing sewer service only to selected
1
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portions of the area.
A major Impact of the No Action alternative is the threat to water
quality and public health by continued reliance on existing systems. This
threat will continue as long as on-site disposal systems and poorly
maintained and/or operated package plants are used. However, most of the
existing systems appear to be operating adequately, and the falling
systems could be repaired, upgraded, or replaced by their owners to pro-
vide satisfactory wastewater treatment. Another consequence of this
alternative is the continued need for septage and sludge disposal.
Treatment of wastewater by existing systems would continue with
the formation of a Maintenance District, but responsibility for maintain-
ing the systems would become the responsibility of the District. Envir-
onmental impacts of this alternative include those described for the No
Action alternative. However, the potential public health and water
quality threats would be considerably reduced by better monitoring and
maintenance. Residents within the District would be required equally
to support the District financially, regardless of the amount of mainten-
ance their own system required.
The most Important beneficial environmental impact of sewering an
area would be to reduce the threats to human health and water quality
imposed by the existing systems. Replacing existing package plants with
sewers would also result in a net saving of electrical energy. However,
the sewer option might lead to increased growth rates, strip development
along the sewer line, and a greater population density in the areas where
sewers were installed. Residents currently using satisfactory systems
would be required to connect and/or contribute financially to the new
sewer system. Additionally, If an area's sewers were connected to the
City of Durango's system, the area could be annexed by the City at a
future date under the City's implied consent rules.
Based on engineering analyses and public involvement, the following
recommendations were made for wastewater management:
Local treatment plants with sewers were recommended for both
the Hermosa and Loma Linda areas. Citizens in the Grandview area
2
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expressed a preference for connecting the area with the new wastewater
treatment plant that Durango was planning to build several miles
downstream of its existing facilities. However, the city may expand
its facilities at the existing site rather than relocating at the downstream
site, which is closer to the Grandview area. In that case, the first choice
alternative recommended for the Grandview area would no longer be feasible.
Consequently, Grandview residents attending a public meeting agreed that a
lagoon system at Grandview would be the preferred alternative in the absence
of a new City of Durango treatment plant at the downstream site the city had
considered earlier. Aerated lagoons are the systems considered most effective
in each of the three recommended areas.
Short interceptors connecting with the City of Durango system were
recommended for parts of the Junction Creek and Lightner Creek. Study Areas.
The remainder of these Study Areas will be unsewered and will continue to
rely on existing systems.
The No Action alternative was recommended for both the Florida Road
and West Animas Study Areas.
3
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CHAPTER 2
PURPOSE AND NEED
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CHAPTER 2
PURPOSE AND NEED
The purposes of this EIS are to analyze and disclose the effects
of providing or not providing sewer service to presently unsewered
areas outside the service area of Durango, to analyze alternative means
of solving the wastewater management needs of the Study Area in the most
environmentally sound, cost-effective manner, and to examine potential
impacts associated with developed alternatives on the significant
environmental issues.
On February 28, 1978, a wastewater treatment facilities plan (201 Plan)
for the City of Durango was submitted to EPA for approval. The plan
addressed the wastewater management needs for the 93 square mile 201
planning area designated by the State Health Department. Included with-
in the planning area are the Animas River Valley from the Southern Ute
Indian Reservation boundary north to Bakers Bridge, Lightner Creek, the
Upper Florida River area, and the Florida Mesa area, which includes
Grandview, Loma Linda, and Air Park. (See Figure 2.1). The plan recom-
mended the construction of a new wastewater treatment plant for Durango
with a capacity of 5.36 million gallons per day (MGD). This plant
capacity would be sufficient to treat the wastewater generated by approx-
imately 37,000 people expected in the vicinity of Durango by the year 2000.
The plan also recommended construction of 28 miles of interceptor sewers
into presently unsewered areas in order to eliminate several small pri-
vately owned sewage treatment plants that were thought to be polluting the
Animas River and its tributaries. The proposed interceptors would also
provide sewage treatment service in areas where septic systems were
allegedly failing and they would accommodate anticipated future growth
in the Study Area. In addition to the proposed facilities, the 201 Plan
concluded that no economically feasible means of serving the wastewater
4
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560
201/EIS STUDY AREA
Original 201/tIS
Study Boundary
AREA 1- Harmosa
AREA 2 - Junction
Craak
AREA 6- Wast Animaa
AREA 3- Lightnar Craak
1 Ourango Wast
AREA 5- Florida Road
OURANGO
Antandad into
Original Study Araa
AREA 4- Grandviaw, Loma
Linda & All Park
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needs of the Upper Florida River and the Florida Mesa portions of the
Study Area exist.
EPA's review of the proposed facility plan revealed a number of
significant issues that satisfied the regulatory criteria for prepara-
tion of an EIS (40 CFR Part 6.510). These issues arose primarily from
the interceptors portion of the facility plan and they involved signifi-
cant land use questions, conflicts with wildlife winter range, flood
plains, historic and recreational resources (Including the Denver and
Rio Grande Narrow Gauge Railroad), induced growth and strip develop-
ment. Additional concerns of the Study Area which are associated with
the Facilities plan that have been identified include: water quality,
land suitability for conventional septic tank systems, point source
problems, air quality, economic costs, and growth rates and distri-
bution patterns within the Animas Valley.
Six portions of the Study Area in which environmental issues are
significant were identified. Maps of these areas which include features
referred to in later chapters are presented in Figures 2.2 through 2.6.
All of these areas are outside of the Durango City limits.
EPA determined that these areas needed to undergo further engineering,
environmental, and economic analysis in a combined 201 plan update and
environmental impact statement effort. This effort is aimed at assuring
that the facility plan for the entire Study Area will be responsive to
both local needs and EPA's environmental responsibilities.
In order to avoid delays in providing needed sewage treatment
capacity for Durango, EPA, the City, and the Colorado State Health
Department agreed in 1978 to modify the design/construction of a new
sewage treatment plant while additional facility planning work and
environmental analyses were being done. Work has proceeded with the
design and specifications for a new 4.0 MGD plant, which should provide
sufficient capacity to accommodate Durango's anticipated sewage treatment
needs for an initial staging period. However, the City of Durango has
undertaken a re-evaluation of the site and treatment process for the new
plant. This re-evaluation study is independent of the EIS and 201
plan for the outlying areas, but it may affect certain alternatives
being considered in the EIS.
6
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FIGURE 22
HERMOSA STUDY AREA
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0IB8M*?a»SIi
FIGURE 2.3
WEST ANIMAS
JUNCTION CREEK and WEST
ANIMAS STUDY AREAS
Uatsrfall
Village
JUNCTION CREEK
North Round*ry
West Animas
Sanitation
District
*Sprin»
Creek
Drainage
Sailing
Hawks
Subdivision
.Jacob's Cliffs
DayslopMnt
Sanitation
District
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iCXMiMk
Balling
FIGURE 2.4 LIGHTNER CREEK STUDY AREA
Jacob's CI
Mobil*
X
Llghtner Creek Sanitation
District Boundaries
Swiss
Chalet
Motel
^37svO
Durango West
Subdivision
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FIGURE 2.5 GRANDVIEW / LOMA LINDA
STUDY AREA
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r^yM'jgaii
FIGURE 2.6 FLORIDA ROAD STUDY AREA
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The need for this study stems from existing and/or anticipated
problems arising from current wastewater handling practices in the Study
Area. Some of the package plants have histories of recurrent failures
and are intermittently degrading water resources in the area, especially
in Hermosa and portions of Junction Creek and Lightner Creek. Continued
reliance on individual on-site disposal systems, under increasing popula-
tion pressures, poses a threat to public health and to water quality.
This is especially important in the Grandview/Loma Linda area which is
dependent on ground water resources for domestic water supply. Figure
2.7 shows the location of multiple customer wastewater facilities examined
in the 201 study and indicates those with a history of problems or which
the State Health Department considers to pose a future problem. The
location and operation status of individual on-site disposal systems are
shown in Figures 2.8 through 2.12.
One of the issues of the present study concerns whether or not the
wastewater handling problems currently existing in the Study Area would
best be solved through enforcement actions against individual violators
or through the construction of new facilities. In the past, State and
local enforcement actions have not been effective in assuring reliable
operation, maintenance, and improvement of privately owned multiple
customer systems (package plant systems receiving wastewater from more
than one residence or business). Therefore, one of the underlying
assumptions of this study is that enforcement and regulatory actions
will not solve the water quality and public health problems posed by
the failing systems.
12
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MULTIPLE CUSTOMER
WASTEWATER FACILITIES
CLOSED CIRCLES OENOTE SYSTEMS
WITH A HISTORY OF PROBLEMS.
IN NEED OF REPAIR, AND I OR FOR
WHICH FUTURE PROBLEMS ARE
ANTICIPATED.
O 1
MILES
i
N
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FIGURE 2.8
INDIVIDUAL ON-SITE DISPOSAL SYSTEMS
IN THE HERMOSA AREA
M LES
J
4>
£
©Trimble
Closed circles denote systems
with high ground water, high
percolation rates, in need of
repair, or with a history of
past problems.
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INDIVIDUAL ON-SITE DISPOSAL SYSTEMS
IN THE JUNCTION CREEK AND WEST
ANIMAS AREAS
MILES
/' Chaprrnhv-/^
Q\ | Lake
^°\' / 1
Animas
City >
Mountainl
Closed circles denote systems
with high ground water, high
percolation rates, in need of
repair, or with a history of
past problems.
Durango
City
Limits
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INDIVIDUAL ON-SITE DISPOSAL SYSTEMS
IN THE LIGHTNER CREEK AREA
Closed circles denote systems
with high ground water, high
percolation rates, in need of
repair, or with a history of
past problems.
To
-Durango
West
tr-
ft
t
i
n
25
Canyon Rd
/•' Wildca
1 I
MILES
-------
INDIVIDUAL ON-SITE DISPOSAL SYSTEMS
IN THE GRANDVIEW / LOMA LINDA AREA
1
Grafidview O
Pliion | „
o i«Luj jD-uyJ-
'-•w— 7
- v
Loma Linda
10
18
6U
5U
VS. I
MILES
7U
8U
Closed circles denote systems
with high ground water, high
percolation rates, in need of
repair, or with a history of
past problems.
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INDIVIDUAL ON-SITE DISPOSAL SYSTEMS
IN THE FLORIDA ROAD AREA
12
10
T ~
15
13
17
*'
L>
To
Durango
Closed circles denote systems
with high ground water, high
percolation rates, in need of
repair, or with a history of
past problems.
MILES
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CHAPTER 3
DESCRIPTION OF ALTERNATIVES
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CHAPTER 3
DESCRIPTION OF ALTERNATIVES
PREVIOUSLY RECOMMENDED ALTERNATIVE
The original 201 Facilities Plan (HDR, 1977) recommended a cen-
tralized wastewater treatment facility for the Durango area and several
interceptor sewer lines into the outlying areas to collect and convey
wastewater. The original 201 Plan assumed that the Study Area boundary
constituted an expansion of the Durango service area and therefore
required that new interceptor sewers be provided to service these
areas. The original recommended alternatives for the outlying areas
consisted of several different interceptors. These interceptor sewers
were to convey sewage from the outlying areas to the new treatment plant.
The cost of these facilities was estimated at about $13,000,000 in 1977,
and the yearly cost of operation and maintenance was about $400,000.
The previously recommended facilities are summarized in Table 3.1 and
illustrated in Figure 3.1.
In November 1979, Cap Allen Engineering was hired by the County with
201 grant funds obtained through the City to complete or update the
Facilities Plan under the direction of a citizen's advisory group
(CAG) established by the County. The results of the update are summarized
below.
ALTERNATIVES CONSIDERED IN FACILITIES PLAN UPDATE
The update of the Durango Facilities Plan (Allen, 1980) examines
the areas outlying the City of Durango in La Plata County for waste-
water treatment requirements. The geographic limits of the update are
smaller than the original 201 Study Area. The update focuses on confined
population centers which, in the view of the CAG, are likely to develop
pollution problems and wastewater treatment needs. Six specific areas of
19
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TABLE 3.1
SUMMARY OF ORIGINAL RECOMMENDED
ALTERNATIVES FOR OUTLYING AREAS
SERVICE AREA
Upper Animas - N.
end of Durango to
Baker's Bridge
Junction Creek - N.W.
corner of Durango into
Junction Creek drainage
Florida Road - N.W.
corner of Durango
along Florida Road to
Animas R. drainage boundary
Vilson Gulch - From
new treatment plant up
Wilson Gulch along
U.S. Highway 160
Lightner Creek
INTERCEPTOR
LENGTH(Ft.)
64,000
10,000
12,000
18,500
Through-City - New
areas of growth
through City
Goeglein Gulch - E.
of Ft. Lewis College
golf course complex
Not presented
19,000
9,000
SIZE
(Inches)
8-12
10-12
21-27
10-12
LIFT
STATIONS(No.)
COMMENTS
Provides capacity for the area
cnat of the AnIrons R. In thr
upper reaches more suitable
for development.
Serves the Junction Creek
drainage area.
Serves development along
Florida Road.
Serves the Grandvlew
Pinyon Acres areas.
and
To be constructed by Lightner
Creek Sanitation District.
Colorado Department of Health
has deemed this as not grant
eligible.
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ORIGINAL RECOMMENDED FACILITIES
FOR OUTLYING AREAS
Upper Anlmat Interceptor
Junction Creek Interceptor
Florida Road Interceptor lExtensionl
Through City Interceptor
Goeglein Gulch Interceptor
Wilson Gulch Interceptor
Treatment Plant Interceptor
Ughtner Creek Interceptor
DURANGO
160
Treatment Plant Site
Soure* HOR, 1977
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study are identified:
• Hermosa
• Junction Creek
• Lightner Creek
• Grandview/Loma Linda
• Florida Road
• West Animas
Because wastewater management needs vary widely among areas, a set of
wastewater management alternatives and associated costs was developed
for each area. These alternatives are discussed by area below. More
detailed information about the alternatives is provided in the updated
Facilities Plan (Allen, 1980) (hereafter referred to as Facilities Plan).
Hermosa
Wastewater in the Hermosa area is currently being treated by 19
multiple customer sewer facilities (package plants or aerated septic tank
systems serving more than one residence or business). Four of these
facilities are located in the area north of Hermosa to Baker's Bridge.
Additional facilities consist of- individual on-site septic tanks, aerated
tanks, and evapotranspiration systems of various ages and conditions.
The principle wastewater management concern in the Hermosa area
is the potential for pollution by the existing treatment facilities.
Results of recent ground and surface water monitoring in the area are
inconclusive. Indicator parameters of wastewater pollution do increase
in the Animas River in this area, but still meet stream water quality
standards. Large portions of the area are in the Animas River or Hermosa
Creek flood plains, and springtime ground water levels are often near
the surface; both of these can be constraints to successful operation
of local treatment systems.
Package plants in the area typically discharge to ditches or
drainage swales which are tributary to the Animas River. The low,
irregular flows and high nutrient loads of the discharges create stagnant
pools, with algal blooms in warmer months. This situation and the overloaded
plants themselves can create nuisance odors and potential health problems
at certain times of the year. These problems are slightly offset by the
fact that the drinking water is supplied to the area by the Animas Water
Company. However, this does not protect against the risk of exposure to
disease-causing agents through ingestion or contact with polluted ditch
or drainage water.
22
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In the Hermosa area, increased building on existing lots will
create conflicts in wastewater management in the area. The problem
of pollution, while currently not acute, will likely increase with
continued use of septic tank systems and proliferating package plants.
Five alternatives were proposed in the Facilities Plan for the
Hermosa area. A brief summary of each of these alternatives is pre-
sented below.
Alternative 1 - Formation of Maintenance District
This alternative involves the formation of a Maintenance District.
Its function would be to maintain and operate the package wastewater
treatment plants in the area, and to monitor and help maintain septic
tank systems. In addition, the District would have authority to
approve specifications and maintenance requirements of future sewage
facilities in the area.
Equipment needs of the District could include septage pumping
equipment, water chemistry testing equipment, maintenance tools, and
vehicles. At a minimum, the District would need a Class C certified
wastewater treatment plant operator. The responsibilities of this
individual would include record keeping, water sampling, monitoring
of plant operations, and maintenance. Certain of the equipment needs
would be eligible for 201 grant funding, but the costs of operation for the
district would have to be borne locally.
Alternative 2 - Collection and Interceptor Lines to Durango
In this alternative, wastewater from the Hermosa area would be
conveyed to Durango to be treated at the City of Durango wastewater
treatment facility. It would involve laying an eight- to ten-inch
interceptor line along the Animas Valley from the City of Durango
system to Hermosa Creek. It would also require the construction of
collectors in the Hermosa area, and three lift stations. In addition,
the North Durango interceptors would have to be upgraded. The proposed
interceptor lines for this alternative are shown in Figure 3.2
Alternative 3 - Central Wastewater Treatment Facility
In this option, a wastewater treatment facility would be built
in the vicinity of Hermosa to serve the needs of the immediate area.
23
-------
rfi
Alternative
/5§
Alternative 2
Figure 3.2
€
it
3
Proposed Sewer Lines for Alternatives
2 and 5 in the Hermosa Area
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A 0.25 MGD aerated lagoon system is proposed to provide service to
the area. Preliminary engineering indicates that a lagoon system
which provides 3-day aeration, 8-day aeration, 2-day settling with
comminution, a media filter and chlorination best meet the area's
needs. This type of system avoids problems of sludge handling and
disposal. Effluent discharge is to the Animas River. Two subalter-
natives associated with this plan include (1) modification of the
aeration equipment to accommodate wind energy as a supplemental energy
source and (2) land application of the treated effluent.
The wind energy and land application aspects of this alternative
were determined not to be cost effective and eliminated from consid-
eration during early stages of the planning process. Alternative 3 was
selected in the Facilities Plan to be the recommended alternative. Three
different configurations of sewer lines serving different portions of the
Hermosa area were developed as subalternatives for Alternative 3 and are
shown in Figure 3.3.
Alternative 4 - No Action
The No Action alternative is the continuance of the status quo.
Alternative 5 - Service Area Extension
This alternative is essentially a sub-option to Alternatives
2 and 3. It would extend sewer lines in both of these Alternatives
north from Hermosa to Baker's Bridge as shown in Figure 3.2. Lift stations
would probably be required. Possible constraints to this option are that
the area has a very low density of dwellings, and that two multiple-customer
establishments in the area have recently built private treatment facil-
ities which are expected to provide reliable service for a long period.
Junction Creek
The Junction Creek area currently has aerated septic tank sys-
tems with evapotranspiration beds or open evaporation ponds, and
one package plant wastewater treatment system.
The Junction Creek Mobile Home Park owns and operates the single
package plant. The system consists of an extended aeration unit fol-
lowed by a clarifier, sand filters, and chlorination. Discharge is
to Junction Creek. Wide variations in effluent quality and fluctua-
25
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FIGURE 3.3
J
N
I
Si.
WOOO'N'
AWll
V
BLUC SKY I y
RANCH ft \ /
•" # V /
Fore* mmmmmmmm \ . r
mhp n
Approximate limits, 100 yt Flood Pfsin
I WESTERLY
HERMOSA SYSTEM
X
vi
)
j
LEGEND
- Servic# Boundary
™" Interceptor
....... Sewer Line
PP Package Plant
HHP Mobile Home Par*
C.G. Campground
1000 500 0
o
yNORTH PARK
l
I/
¦31 1 C |
r" ^
f OtadMirv* to AntmM /
,-^v rivw
/
-------
tions in stream flows create varying impacts on surface water quality.
The area east of Chapman Lake has a high water table and slow soil
percolation rates. Lots in this area are less than three acres and
therefore require evapotranspiration systems. Existing septic tank-
leach field systems require constant monitoring to assure proper
operation.
The area adjacent to Junction Creek has a very high water table
and very rapid percolation rates. Effluent disposal systems asso-
ciated with new construction in this area must be designed to operate
properly under these conditions.
Six alternatives were proposed for the Junction Creek area.
Each of these alternatives is briefly described in the following
paragraphs.
Alternative 1 - Collection and Interceptor Lines to Durango
Under this option, an interceptor would be built to collect and
convey wastewater generated in the Junction Creek area down the
Junction Creek drainage to the City of Durango sewage treatment
facility. Since the increased flows under this plan would overload exist-
ing sewer lines in northwestern Durango, the present interceptor in
this part of the city would have to be replaced under this option to
accommodate the increased flows. The approximate alignment of the proposed
interceptor is shown in Figure 3.4.
Alternative 2 - Collection and Interceptor Lines to West Animas
Sanitation District via Spring Creek
Wastewater from the Junction Creek area would be conveyed to the
newly formed West Animas Sanitation District in the Animas River Valley
under this alternative. Once within the District boundaries, waste-
water would be conveyed to the City of Durango's wastewater treatment
plant. The system would involve pumping the wastewater from the
Junction Creek drainage over the low saddle into the Spring Creek
drainage. This alternative would provide service only to the Chap-
man Lake area and the upper reaches of the Junction Creek drainage.
Service would not be provided to Junction Creek Trailer Park. Figure 3.4
shows the approximate location of the proposed pipeline.
27
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Figure 3.4. Proposed Sewer Alignment for Alternatives I and 2
and Proposed Treatment Facility Location for
Alternative 4 in the Junction Creek Area.
thtuhU
Village
•Horth Boundary
Wot Anlmaa
Sanitation
District
Alternative 2
Alternative
Facility
Sailing
Hawks
Subdivision
Riverside
Development
Alternative I 1^1$^
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Alternative 3 - Formation of a Maintenance District
Under this alternative, a local sewage treatment facility would be
built in the Chapman Lake area. The proposed Chapman Lake facility
and the existing Junction Creek Trailer Park package plant would then
be operated by the District. In addition, the District would monitor
and help maintain on-site disposal systems in the area. The District
would also have authority to approve specifications and maintenance
requirements of future sewage facilities in the area.
Equipment and operational needs of the District would be similar
to those discussed for the Maintenance District described for Hermosa.
Alternative 4 - Central Wastewater Treatment Facility
A centralized wastewater treatment system would be constructed
to serve the Junction Creek drainage. Treatment would be provided by
an aerated lagoon system and would serve Durango Estates Subdivision,
Sailing Hawks Subdivision and other developments and single family res-
idents. Service would not be provided to. Junction Creek Trailer Park
because of construction or operational costs to serve this one facility
from the lagoon. The approximate location of the proposed wastewater
treatment facility is shown in Figure 3.4.
Alternative 5 - Short Interceptor
A short interceptor would be constructed along Junction Creek
from the Junction Creek Mobil Home Park to the City of Durango sewer
system. This option would eliminate the package plant in the Junction
Creek area which has a history of operation problems. This alternative
was selected as the recommended plan and is shown in Figure 3.5.
Alternative 6 - No Action
The No Action alternative is the continuance of the status quo.
Lightner Creek
The Lightner Creek area can be divided into three areas in terms of
wastewater management strategies: 1) Swiss Chalet Motel, 2) County Road
207-the Lightner Valley, and 3) Durango West.
The Swiss Chalet Motel is located just west of the Lightner Creek
Sanitation District boundary. Wastewater is currently treated by a septic
tank-leach field system. The system does not show any indication of
29
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FIGURE 3.5
V
Junction Creek MHP
JUNCTION CREEK INTERCEPTOR
\8*
100 Vear Rood Limit" ¦. V
Durango City Limits
Clovis
1000 500 0
2000
LEGEND
¦ww Existing Sower Interceptor
New Interceptor
MHP Mobile Home Park
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failing, but potentially could in the future (Allen, 1980). Critical
feature of the system which may aggravate a failure are land constraints,
and high ground water and flooding due to proximity to Lightner Creek.
Three privately owned and operated wastewater treatment facilities
are located in the Lightner Valley. E. B. Howard Condominiums operates
a concrete three-cell aerated lagoon followed by land application. The
Lightner Creek Mobile Home Park operates a 2-celled aerated lined lagoon
with chlorination. The Safari Campground uses an extended aeration unit.
All three of these systems are operated with limited problems. The
greatest concerns are the relationship of domestic water supply intakes
along Lightner Creek below discharges and the potential for flooding.
The Durango West subarea receives wastewater treatment from the
Durango West Metropolitan District. The District operates a 100,000
gallon per day (GPD) extended aeration plant that has experienced
startup problems. Discharge of the treated effluent is to the dry
Coal Gulch drainage. The greatest impacts of this facility are
associated with visual and odor problems in Coal Gulch. The discharged
treated effluent is absorbed into the dry drainage bed and does not
directly enter any surface waters.
Four alternatives for sewage treatment were proposed for the
Lightner Creek/Durango West Study Area.
Alternative 1 - Collection and Interceptor Line to Durango
This alternative consists of building interceptor lines of various
lengths up the Lightner Creek Drainage. Sewage from these areas would
be treated at the City of Durango's wastewater treatment facility. All
options under this alternative would include building an interceptor
connecting to the existing Lightner Creek Sanitation District inter-
ceptor. This line presently ends about two miles west of the Durango
City limits. Four different interceptor systems have been proposed,
each serving a different portion of the proposed service area.
a> Interceptor Line to the Wildcat Canyon Road - This option
would serve those users between the end of the present
Lightner Creek Sanitation District and Wildcat Canyon
Road. U.S. Highway 160 would have to be crossed to serve
the Swiss Chalet Motel. Alternative 1 with this sewer
31
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line alignment was selected in the Facilities Plan as the
recommended alternative and is shown in Figure 3.6.
b. Interceptor Line to Lightner Valley along Lightner Creek -
This option would include extending the interceptor proposed
in option "a" west to the divergence of Lightner Creek and
U.S. Highway 160. It would consist of about 8,000 feet
of interceptor laid through difficult terrain with very
few users along its alignment. However, this line would
be necessary to implement either options "c" or "d" under
Alternative 1, as shown in Figure 3.7.
c. Interceptor to the Head of Development in Lightner Valley -
The interceptors described in "a" and "b" would be extended
northwest along Lightner Creek. This line would consolidate
the users of three package plant type users plus private
homeowners in the area. Approximate alignment is shown in Figure 3.7.
d. Interceptor Line to Durango West - The interceptor described
in "a" and "b" would be extended westward to the Durango West
community. This would be a very long interceptor with no
services as it would pass through undevelopable land. A
density of 1400 units would be necessary in Durango West
for this project to be feasible. Proposed location of this inter-
ceptor is shown in Figure 3.7.
Alternative 2 - Formation of a Maintenance District
This alternative involves the formation of a Maintenance District.
Its function would be to maintain and operate the package wastewater
treatment plants in the area, and to monitor and help maintain septic
tank systems. In addition, the District would have authority to
approve specifications and maintenance requirements of future sewage
facilities in the area.
Equipment and operational needs of the District would be similar
to those described for the Maintenance District for Hermosa.
Alternative 3 - Central Wastewater Treatment Facility
Under this alternative wastewater flows in the Lightner Creek
drainage would be conveyed to a central treatment facility in the
baSin. Treatment would be provided by an aerated lagoon followed by
a discharge to Lightner Creek. The lagoon site would be at the Lightner
Creek Road tumoff from U.S. Highway 160, as shown in Figure 3.7. The
pipeline alignment would be the same as in Alternative 1-C, above.
Alternative 4 - No Action
The No Action alternative is the continuance of the status quo.
32
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Smart's
fiuXo^.
Swiss Chalet
Motel
LEGEND
Existing Sewer Interceptor
New Interceptor
500
5 «0
250
1000
FEET
Wildcat
Canyon Rd.
u>
-------
Sailing
Bavlta
Subdivialoo
Figure 3.7 Proposed Sewer Alignments for Alternatives I and 3,
and proposed Facility Location for Alternative 3
in the Liqhtner Creek Area.
Jacob's G
Davalopaa
Alternative |-c,
Alternative 3 Pipeline
I
Llfthtnar Craak
Mobil. Ho« »atk
m
Alternative 3
"facility
Alternative I - b
Alternative I-a
Alternative
Existing Durango West
Treatment
Lightner Creek Sanitation
District Boundaries
Ol
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Grandview/Loma Linda
The Grandview/Loma Linda area is second only to Hermosa in the
number of multiple customer wastewater treatment facilities.Other residential
facilities utilize a multitude of systems ranging from septic tanks to
aerated lagoons. The principal constraint to land disposal systems in
the area is the tight clay soil of the Florida Mesa. This condition will
perpetuate the use of surface effluent disposal techniques such as
evapotranspiration ponds following septic tanks and package plants.
With the exception of irrigation ditches, there are no permanent
drainages in the area. Discharges that have occurred from the exist-
ing holding ponds consist of 100 percent effluent. Odor and health
effects become a critical concern in such instances. Odor and nui-
sance situations have also been noted in areas of high density due
to poor maintenance schedules. Another concern is the dependency of the
area on local well water for domestic water supply. Although no ground
water pollution is evident at present, the soils in the area are such
that cracks could develop under dry conditions thereby providing a
means for inadequately treated wastewater discharged to lagoon or ditch
systems to contaminate local aquifers.
Alternative 1 - Collection and Interception Line to Durango
This alternative consists of building collection systems and
interceptor lines to various communities in the area. The interceptors
would connect with the City of Durango system, and treatment would
be at the City of Durango wastewater treatment facility. The feasibility
of this alternative would be adversely impacted if the new Durango
treatment plant is not built at the site proposed in the original Facil-
ities Plan prepared by HDR. Various proposed pipeline configurations for
for this alternative are shown in Figure 3.8.
a. Interceptor line to Pinon Acres KOA Campground - This option
would provide for an interceptor and collector system from
the City of Durango sewage treatment plant through the Grand-
view and Pinon Acres areas to the Pinon Acres KOA campground.
Because of land constraints along U.S. Highway 160, the
interceptor corridor would be the abandoned Denver and Rio Grande
Western Railroad right-of-way. A number of collectors would be
needed in this system due to the scattered nature of the present
population. The interceptor would be sized to also accommodate
use by the Loma Linda and Florida Mesa areas. A separate
35
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,32
Alternative la
Alternative lb
6U
40
130
Alternative 5
1IU
"7U
iou
12U
Figure 3.8 Various Proposed
Alternatives I and
Loma Linda Area.
Pipeline Configurations for
5 in the Grandview /
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sanitation district would be formed under this
option.
b. Interceptor Line to Lama Linda and Florida Mesa - This
option would extend the interceptor system proposed in
option "a" into the Loma Linda and Florida Mesa areas. A
gravity collection system could be used in the Loma Linda
and Falfa areas, but a long force main would be required
to move the sewage to the proposed Grandview/Pinon Acres
interceptor. This option would provide central sewers to
virtually the entire area. The abandoned Denver and
Rio Grande Western Railroad right-of-way might be further
utilized in this option.
Alternative 2 - Central Wastewater Treatment Facility - Loma Linda
and Falfa Areas
A central aerated lagoon with associated interceptors and collectors
would be built for the Loma Linda and Falfa areas under this alternative.
A gravity feed system could be utilized to convey wastewater to the
treatment facility. A local sanitation district would be formed for
the area. This alternative was selected as the recommended plan to
serve the Loma Linda area and is shown in Figure 3.9.
Alternative 3 - Central Wastewater Treatment Facility - Grandview
and Pinon Acres Area
This alternative would provide for the construction of a central
aerated lagoon with associated interceptors and collectors in the
Grandview and Pinon Acres areas. A sanitation district for the area
would be formed under this alternative. This alternative was selected
as the recommended plan for the Grandview area and is shown in Figure
3.10. However, Grandview residents would still prefer to connect to the
Durango system if the new Durango treatment facility is located at the
site proposed in the original Facilities Plan prepared by HDR, which
would eliminate the need for a central treatment plant at Grandview.
Possible alignments connecting to the proposed Durango treatment plant are
shown in Figure 3.11.
Alternative 4 - Formation of a Maintenance District
This alternative involves the formation of a Maintenance District.
Its function would be to maintain and operate the package wastewater
treatment plants in the area, and to monitor and help maintain septic
37
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FIGURE 3.9
lb US Hwy 160
County Road 2C1
Florida Mesa
.• School
• ••
PP
LOMA LINDA
PP
LOMA C.INDA SYSTEM
Approximate
of Aerated
-------
GRANDVIEW SYSTEM
Florida
Farmers
Ditch
Approximate Location
of Aerated Lagoons
County Road
233
• •
Service Boundary
Sewer Main
Old Denver & Rio Grande
Western Right of Way
1000
600
1000
2000
FEET
Sewer User
o
-------
To Durango
PIPELINE CONFIGURATIONS FOR
ALTERNATIVE GRANDVIEW SYSTEMS
TO PROPOSED
„DURANGO S.T.P.
" N
. i
Configuration 1,
U.S. Hw» 16f
• Sewer Main
.Old Denver & Rio Grande
Western Right of Way
Approximate site of
proposed lagoon
Configuration 2
IOOO
2000
-------
tank systems. In addition, the District would have authority to approve
specifications and maintenance requirements of future sewage facilities
in the area.
Equipment and operational needs of the District would be similar to
those discussed for the Maintenance District for Hermosa.
Alternative 5 - Interceptor Line to Animas Air Park
This alternative is simply an extension of the interceptor system
proposed in Alternative 1 into the Animas Air Park area. Treatment of
sewage would be by the City of Durango wastewater treatment facility. The
suggested pipeline configuration is shown in Figure 3.8.
Alternative 6 - No Action
The No Action alternative is a continuance of the status quo.
Florida Road
With one exception, wastewater in the Study Area is treated by
individual on-site disposal systems. The systems vary widely, ranging
from conventional septic tank-leach field systems to aeration tanks/
evapotranspiration beds.
The B & C Mobile Home Park has a multiple customer aerated tank sys-
tem with a large leach field. This system has experienced failures
of the leach field and the aeration tanks have been inoperable. It
has been recommended trhat this system be renovated at the owner's expense
(Allen, 1980).
The Florida Road area has a wide range of soil types which gen-
erally require special consideration for septic tank systems. Along
Florida Road tight Mancos shale clays occur which require evapotrans-
piration beds or oversize leach systems. In the Florida River Valley
percolation rates are very rapid and high ground water represents an
additional constraint. These conditions require special design con-
siderations for new on-site wastewater disposal systems.
Five alternatives were proposed for the Florida Road Study Area.
Alternative 1 - Collection and Interceptor Lines to Durango
This alternative includes running an interceptor northeast from
the end of the existing line at Timberline View Estates. The new
41
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line would run along Florida Road to the saddle top divide between
the Florida River and the Animas River. An additional collection
network would be required to provide service to areas north of
Florida Road. Sewage would be treated by the City of Durango waste-
water treatment facility. The proposed pipeline configuration is shown
in Figure 3.12
Alternative 2 - Central Wastewater Treatment Facility
Under this alternative an aerated lagoon with a collection/inter-
ceptor system would be constructed to service the Florida River Valley.
Wastewater treatment in the Animas River drainage of the Study Area
would continue with existing systems. Proposed treatment plant and pipe-
line locations are shown in Figure 3.12.
Alternative 3 - Short Interceptor to Durango
This plan is an abbreviated version of Alternative 1 and involves
extending the sewer interceptor from Timberline View Estates to the
B & C Mobile Home Park as shown in figure 3.12. This interceptor would
receive wastewater from all existing homes along Florida Road, the B & C
Mobile Home Park, and residences in the immediate vicinity of the mobile
home park. Sewage would be treated by the City of Durango wastewater
treatment facility.
Alternative A - Formation of a Maintenance District
Certain improvements to existing wastewater treatment systems
would be made under this alternative, particularly at the B & C Mobile
Home Park. Future operation and maintenance would be coordinated with
an area-wide or county-wide maintenance district upon its creation.
Equipment and operational needs of the District would be similar
to those discussed for the Maintenance District for Hennosa.
Alternative 5 - No Action
Although this alternative was not analyzed in the Facilities Plan,
it was selected as the recommended plan for the Florida Road area by
the Citizens Advisory Group after a public meeting in the area. This
alternative would continue the status quo.
West Animas
Existing wastewater treatment in the West Animas area is by indi-
vidual treatment systems and by a non-discharging extended aeration
42
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Alternative 2
Pipeline
Saddle Top
Divide
Florida River
J Estates
Oevelo
B 4 C Mobile
Home Park
Riverside
Development
Alternative I
*South Boundary
West Animas
Sanitation
District
Alternative 2
Treatment Plant
Alternative 3
Timberline
View Estates
Hlllcrest
Figure 3.12. Proposed Sewgr Lines for Alternatives 1,2,and 3, and Alternative 2
Treatment Plant Location in the Florida Road Area.
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plant followed by an oxidation ditch. The existing residential units
in the West Animas area are fairly old and it is suspected that several
leach fields need to be upgraded to current standards. The area is
constrained for on-site systems by the Animas River flood plain and
high ground water. The Lazy—U—Rancho operates an extended aeration
plant followed by a non-discharging oxidation ditch. The facility
is overloaded and 24-hour summer blower operation is required simply
to prevent odors, with a resulting low level of treatment (Allen, 1980),
and high operating costs due to energy consumption.
The recently created West Animas Sanitation District provides a
sewer interceptor line into the southern edge of the area. This
sewer line has an ultimate volume of 0.4 MGD and thus is not limited
by capacity. There are also plans to construct an aerated lagoon system
to serve the Waterfall Village.
Four alternatives were proposed for the West Animas area.
Alternative 1 - Collection dnd Interceptor Lines to Durango
This alternative proposes inclusion of the Study Area into the
recently formed West Animas Sanitation District. The sewer inter-
ceptor line that presently ends at the southern end of the Study Area
would be extended to north of Falls Creek. At least one lift station
would be required on the new interceptor. Sewage would be treated by
the City of Durango wastewater treatment facility. Possible alignment of
this interceptor is shown in Figure 3.13.
Alternative 2 - Central Wastewater Treatment Facility
There is an immediate need for wastewater treatment at the Water-
fall Village Condominium project. This alternative would provide this
needed service with the construction of a new aerated lagoon. This
facility would be sized to also accommodate the wastewater flow from
the Lazy-U-Rancho camper park and other developments in the Falls
Creek area. Approximate location of this proposed facility is shown in
Figure 3.13.
Alternative 3 - Formation of a Maintenance District
This alternative would place the West Animas area in a county-
wide or area-wide wastewater management maintenance district. The
proposed Waterfall Village aerated lagoon and the existing Lazy-U-Rancho
extended aeration plant would be included within the District's
44
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Figure 3.13. Proposed Sewer Line for Alternative I, and Alternative 2
Treatment Plant Location in the West Animas Area.
Alternative 2
Treatment Plant
Alternative I
Line \
'South Boundary
Vest Afiima*
Sanitation
District
.Jacob's Cliffs
Development
-------
jurisdiction. The latter facility would be managed on a seasonal basis.
In addition, the District could aid in monitoring and maintaining
individual treatment systems in the area.
Equipment and operational needs of the District would be similar
to those discussed for the Maintenance District for Hermosa.
Alternative 4 - No Action
This alternative was not addressed in the 201 Facilities Plan.
However, residents in the area have expressed a preference for the EPA No
Action alternative and it has been selected as the recommended plan for
this area. Residents feel that present operation and maintenance
problems occurring at existing facilities should be corrected at the
expense of the individual owner.
PROJECT IMPLEMENTATION
Implementation of the projects recommended in the 201 Facilities
Plan for each of the respective Study Areas must adhere to the Federal,
State, and local regulatory framework as well as be responsive to the
needs of the local residents. Factors pertinent to implementing all
of the wastewater management alternatives were presented at length in
the 201 Facilities Plan (Allen, 1980). The following discussion is
based in large part on information presented in the Facilities Plan.
LOCAL REGULATORY FRAMEWORK
The City of Durango presently requires an "implied consent"
agreement from certain extenders and users of their sewage facili-
ties. Essentially, this is an agreement that the user will con-
struct improvements to City Specification and that the user agrees
to annexation by the City at such time as the City may wish to
annex them. Through this type of agreement, the City does all
billing (at an increased rate) and maintenance on sewer mains, man-
holes and lift stations. The agreement becomes the instrument for
performing these services. The City of Durango, through this
agreement, has the power to assess penalties, discontinue service,
and place encumbrances upon the property receiving service. This
is probably a good method of implementation of the Junction Creek
46
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Plan, but holds little promise for the other plans because of large
distances separating the other Study Areas from the City.
Existing Sanitation Districts (Lightner and West Animas) have
established by-laws and rules and regulations identifying the method
by which new users are added. This usually includes a petition process,
public hearing, and signing of an agreement. For the Lightner Creek
Plan, the various property owners would become involved in this petition
process. The L.C.S.D. will require that all improvements be paid for
by the petitioners. Thus a mechanism whereby the City of Durango, as EPA
grantee would enable the petitioners to receive the 75 percent matching
fund would have to be negotiated. The newly formed West Animas Sani-
tation District could accept petitioners from the West Animas Area
by a similar mechanism. It is normal for the City of Durango to have
the right of refusal to petitioners wishing to use District facilities
that empty into the Durango Sewage Treatment Plant. The City is normally
approached first in the petition process.
The formation of a sanitation district under Colorado Statute
(C.R.S. 73-30-20-401-422) is a possibility for the Hermosa, Loma Linda,
and Grandview areas. To do this, a citizens committee is formed and
develops a service plan, including boundaries of the proposed district,
system description, and estimated costs. The La Plata County Commission-
ers then hold public hearings on that plan and designate the Sanitation
District. The District Court judge then holds a court hearing to desig-
nate an election date and certify the legality of the District. An
election is held for a board of directors and for the existence of the
district. The board of directors proceeds with the search for funding,
development of plans, and specifications and construction. The process
through an election takes about five months. An earlier effort to form
a Hermosa Sanitation District failed in an election for formation
(June 10, 1980). However, it is likely that the formation of this district
will be reconsidered in light of this proposed Facility Plan.
The development of a coordinated Management Agency Agreement is of
paramount importance in this plan if the proposals contained in the Facility
Plan are to be implemented using grant funds. The roles and responsibilities of
47
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the various public agencies that might take part in such an agreement
are discussed at length in the San Juan Region 208 Plan (CDLA
and SJRC, 1979, pp. 47-62). Recommendations of this report include
La Plata County areas in the City of Durango sewer system - Lightner
Creek, Junction Creek, and West Animas Valley. The Grandview alterna-
tives recommend utilization of a yet unbuilt City of Durango sewage
treatment plant at a new site, the location of which the City of Durango
may well change through further study. The Loma Linda and Hermosa
alternatives are wholly within La Plata County, and not directly affected
by City of Durango expansion plans; however, the Hermosa plant in
particular is of interest to the City of Durango due to its discharge
location, 11 miles above the Animas Raw Water intake. Thus, the
need exists for close liason between the Durango City Council and the
La Plata County Commissioners at the implementation stages of the 201
Facilities Plan.
USER COSTS
An expensive project, as defined in the Facilites Plan, is one in
which user charges exceed $387.50 per year per household or $32.30 per
month. Expensive alternatives were eliminated during the course of the
201 Study through the public participation process. User costs for
the recommended alternatives presented in the Facilities Plan are as
follows:
Alternative
Capital Cost
Monthly User Cost
Hermosa 1
$ 678,106
$ 8.48/month
Hermosa 2
850,562
8.85/month
Hermosa 3
1,037,619
8.14/month
Junction Creek
58,187
6.84/month
Lightner Creek
73,500
25.50/month
Grandview/Wilson Gulch 1
596,000
11.49/month
Grandview/Wilson Gulch 2
793,000
11.90/month
Grandview/Wilson Gulch 3
819,000
10.68/month
Loma Linda
348,000
11.21/month
RECREATIONAL USE
Section 301 (g) (6) of the Clean Water Act requires the collateral
48
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examination of recreational opportunities in the implementation of a
201 Facilities Plan. Liason with the Heritage Conservation and Recreation
Service and Park organizations and, in particular, the Land and Water
Conservation Fund, may yield fruitful expansions of recreational
opportunities in La Plata County.
The Land and Resource Management Plan (LMP) of La Plata County
utilizes a Parks and Open Space Plan. The capital improvements of
this Facilities Plan should be utilized where possible to implement
those recreational opportunities.
Specific recommendations for recreation in the Facilities Plan
are:
(1) Utilize sewer line easements in Loma Linda, Grandview,
and Hermosa for Bicycle Commuter paths. Both areas are
within reasonable commuting distance by bicycle of
Durango, and such paths would provide incentives to
residents,
(2) Utilize the Hermosa lagoon site as a picnic park area
and to provide fishermen access to the Animas River, and
(3) Investigate the possibility of a ball-field at the
Loma Linda sewage treatment plant site.
Staging of Construction
Under EPA guidelines, a staging period of 10 years would be
required for sewage treatment plants built within this Plan. For treat-
ment facilities, a small aerated lagoon achieves high marginal
savings with increase in size. Excavation, area of liners required,
and land area all decrease per unit volume in a geometric manner
with arithmetic increase in daily flow. This means it costs less to
build and operate a system with excess capacity now that it would to
build a new addition to the system later. Certain equipment needs have
a linear increase with flow, such as oxygen diffusers and blower
capacity. Chlorination equipment and other possible injection processes
would be sized for ultimate design.
Thus, the staging recommended is minimal. Aerated lagoons would be
built and lined to ultimate sizes initially. Diffusion equipment
below water level would be sized at ultimate flow due to the difficulty
49
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of adding such hardware at a future date. Blower sizing and capacity
would be submitted to a cost-effectiveness examination. It may be
possible that blower sizings are also most economical at ultimate
requirements, with lower cycling times at first.
For interceptors, Colorado State Regulations require minimum 8-inch
diameter pipe for public sewers at a low slope of 0.004 (0.4 percent).
Using pipe with a Manning n=0.009 and 75 gallons per capita per day, and
a 3 to 1 peak to average flow, a population equvalent of 3160 persons
can be accommodated at minimum slope. This amount increases with the
square root of the slope. In none of the areas is such a combination of
population and pipe size encountered at the 20-year estimate. Hermosa
is designed with a 10-inch central interceptor and is sufficient for the
2,800 plus total persons expected at the year 2000 and large amounts of
unforeseen growth. In all other areas, utilizing minimum sewer sizings
also allows for an immediate 20-year capacity staging effect.
Implementation Schedule
The construction timetable for the Facilities Plan depends to a
great extent upon (1) the initiative of the private citizens in the respec-
tive Study Areas, (2) the development of a Management Agency Agreement,
and (3) securing funding from EPA through the Colorado Department of
Health. Once La Plata County has accepted its designation as managing
agency for wastewater management in the areas identified in the 208
plan and the necessary agreements with Durango and any other implementing
agency have been made, a significant reduction in time could be realized
through a combined Step II and Step III grant - Engineering and Con-
struction in one application, provided for under EPA regulations for
communities under 25,000 population. This is a category that the
City of Drango, as grantee, would meet.
50
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CHAPTER 4
DESCRIPTION OF THE AFFECTED ENVIRONMENT
-------
CHAPTER 4
DESCRIPTION OF THE AFFECTED ENVIRONMENT*
The Study Area is located in southwestern Colorado in the Animas
River drainage. The area is bordered by the San Juan Mountains to the
north and west, and by plateaus and mesas to the south and east. The
region is a popular recreational area for skiers, bikers, campers,
and sightseers. Durango is the major population center in the Study
Area with trade and tourism its predominant businesses.
TOPOGRAPHY
Elevations in the Study Area range from about 6,400 feet to 8,800
feet above mean sea level. The area is situated in a transitional
area of the Southern Rocky Mountain Physiographic Province and the
Colorado Plateau Province. The Southern Rocky Mountain Province,
represented by the San Juan Mountains, is characterized by high peaks,
great relief, and ruggedness. Rocks are of igneous, metamorphic, and
sedimentary origin, and soils are generally shallow. It is a scenic
area of mixed bare rock and forest, with valuable water and mineral
resources. The Colorado Plateau Province, Navajo Section, represented
by plateaus and mesas, consists of extensive areas of nearly horizontal
sedimentary formations, structural upwarps, igneous structures, steep
walled canyons, and a shortage of water. It is an area of bare
rock, sparse vegetation, and highly varied desert scenery.
Principal features of the Study Area include Animas City Mountain
northwest of Durango, Florida Mesa southeast of Durango, and the Animas
and Florida River valleys.
*Supplemental data on the environment of the Study Area is presented
in Appendix A.
51
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GEOLOGY
The geologic character of the Study Area is quite diverse and com-
plex. Within the Study Area there are nineteen geologic formations and
eleven surficial deposits. Geologic features can be separated into two
general groups along an east-west line north of the City of Durango.
Formations north of this line form the basal structure of the southern
edge of the San Juan Mountains; south of this line the geology has formed
mesas and plateaus. Geologic formations north of the separation line
range in age from Upper Cretaceous to Precambrian (63 to 600 million
years old), while formations south range in age from Quaternary to
Upper Cretaceous (1 to 63 million years old). Quaternary alluvium
is common in most stream beds.
When considering wastewater management in the Study Area, geologic
features must be considered in those areas currently and/or potentially
facing development. These areas are generally restricted to the drain-
age valleys. They consist primarily of water-borne deposits that are composed
of alluvium, terrace gravels, and alluvial fan deposits, and of glacial
till deposits. Alluvium is comprised of silt, sand, and gravel which
is associated with modern flood plains. Terrace gravels are old stream
deposits lying on surfaces above the present flood plain. Alluvial fan
deposits are sand, gravel, and wash deposits set down in a fan-shaped
wedge at the mouths of tributaries. Glacial till deposits are poorly
sorted silt-to gravel-sized material deposited by glacial ice. In the
Animas River Valley north of Durango the majority of the existing devel-
opment has occurred on the alluvial deposits. Alluvial deposits are
also found in the bottomlands of Junction Creek, Lightner Creek and
the Florida River. Northeast of Durango, in the Animas Valley, glacial
till deposits can be found.
The remaining geologic formations in the southern portion of Study
Area have formed the Florida Mesa and the lower segments of the Florida and
Animas Rivers. The Florida Mesa consists of the Animas Formation; the
remaining areas are alluvial deposits from the Animas and Flordia Rivers.
The Animas Formation is a dark vari-colored sandstone, shale, and
conglomerate which contains abundant volcanic and ankosic detritus.
52
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Surficial deposits associated with the Animas Formation include alluvial-
colluvial deposits and some alluvial deposits. The alluvial formations of
the Mesa have surficial deposits of pediment gravels with some colluvial
deposits (gravity transported hillside detrital) on the western edges.
Along the edges of the Florida and Animas River alluvium, and in inter-
mittent drainages off of the Mesa, the San Jose, Nacimiento and Animas
Formations occur.
GEOLOGIC HAZARDS
Geologic hazards are numerous in the Study Area. La Plata County
is in Seismic Zone Two and is subject to moderate earthquake damage.
Although several faults exist in the immediate vicinity of Durango, no
known faults occur within the six areas of study. Other identified
geologic hazards include rock falls, debris fans (areas subject to wash
from tributary streams), unstable and potentially unstable slopes,
areas of high and moderate erosion potential, landslide and mudflow
areas, and slope failure complexes. These hazardous conditions have been
responsible for preventing the development of some sites within the Study
Area. Areas potentially constrained for development by geologic hazards
are shown in Figures 4.1 through 4.6. Specific geologic constraints
for these areas are presented in Appendix A.
SOILS
Soils information for the Study Area is available from the U.S.
Soil Conservation Service (SCS) only in draft form. A preliminary
listing of soils map units in the Study Area and their limitations to •
development are shown in Table 4.1.
High ground water levels, occurrence of floods, excessive slope,
slow permeability, and shallow bedrock are all constraints that could
preclude successful operation of septic tank-leach field systems.
Although actual soil conditions and suitability for waste disposal
systems have to be determined on a site by site basis through soil
tests,the following generalizations can be made. Soil types rated as
"Poor" in Table 4.1 for one or more of the soil characteristics are
generally considered unsatisfactory for such wastewater disposal systems.
53
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FIGURE 4.1
MILES
US Hwy 55
CONSTRAINED AREA
To Durango
_L
AREAS POTENTIALLY CONSTRAINED FOR
DEVELOPMENT BY GEOLOGIC HAZARDS
- HERMOSA STUDY AREA
-------
AREAS POTENTIALLY CONSTRAINED FOR
DEVELOPMENT BY GEOLOGIC HAZARDS
- JUNCTION CREEK STUDY AREA
'Animas
City
Mountain
Durango
City
Limits
CONSTRAINED AREA
MILES
-------
AREAS POTENTIALLY CONSTRAINED FOR
DEVELOPMENT BY GEOLOGIC HAZARDS
- LIGHTNER CREEK/DURANGO WEST STUDY AREA
To
Ourango >¦
CONSTRAINED AREA
To
Ourango
West
1
MILES
Canyon Rd
s
-------
AREAS POTENTIALLY CONSTRAINED FOR
DEVELOPMENT BY GEOLOGIC HAZARDS
- GRANDVIEW/LOMA LINDA STUDY AREA
q a hgvv A
t—i i -f-Jfy
Pinon
Acres
To
Durango
Loma Linda
\ A \9l mW
S Hwy S50
MILES
CONSTRAINED AREA
-------
AREAS POTENTIALLY CONSTRAINED FOR
DEVELOPMENT BY GEOLOGIC HAZARDS
- FLORIDA ROAD STUDY AREA
To
-* Durango
MILES
CONSTRAINED AREA
-------
FIGURE 4.6
AREAS POTENTIALLY CONSTRAINED FOR
DEVELOPMENT BY GEOLOGIC HAZARDS
- WEST ANIMAS STUDY AREA
US Hwy 550
o
9
O 3
H O
CONSTRAINED AREA
I
MILES
-------
TABLE 4.1
SOIL LIMITATIONS AND DEVELOPMENT CAPABILITIES
Animas River
Valley
(Includes Her-
raosa & West
Animas Areas)
SOIL
Werlow Loam
Connerton Loam
Humbarger Loam
Pescar Loam
Garza Loam
Fluvaquent
Rlverwash
Haploborolls Rubble
Fortwingate-Rock
Garza-Clayburn Rock
Goldvale-Fortwlngate
Valto Rock
Ulnta-Leadville-Anvlk
FLOODS
OCCUR
P
P
HIGH
WATER
TABLE
P
P
P
P
EXCESSIVE
SLOPE
P
P
P
P
P
SLOW
PERMEABILITY
M
SHALLOW
BEDROCK
M
M
P
P
EXCESSIVE
SHRINK-SWELL
Florida River
Valley
(Includes
Florida Road
Area)
Florida Mesa
(Includes
Grandview,
Loma Linda,
Air Park Area)
Hesperus Loam
Werlow Loam
Pescar Loam
Plome Loam
Goldvale Loam
Nordic Loam
Alamosa Loam
Clayburn Loam
Fluvaquent
Carracas-Sanchez
Outcrop
Valto Rock
Fortwingate-Rock
Falfa Loam
Heldt Loam
Werlow Loam
Midway Loam
Big Blue Loam
Gaynor Clay
Midway Rock
P
P
P
P
P
P
P
P
P
P
F
P
P
F
P
P
P
P
M
F
F
M
F
F
P
P
P
P
F
M
F
F
P
P
-------
TABLE 4.1 (Continued)
SOIL LIMITATIONS AND DEVELOPMENT CAPABILITIES
SOIL
HIGH
FLOODS WATER EXCESSIVE
OCCUR TABLE SLOPE
SLOW
PERMEABILITY
SHALLOW
BEDROCK
EXCESSIVE
SHRINK-SWELL
Lightner Creek
Pescar Loam
Fortwingate Loam
Anvlk Loam
Nehar Loam
Cold Creek Loam
Hesperus Loam
Midway Loam
Goldvale Loam
Carracas-Sanchez
Outcrop
Fortwingate-Rock
Haploborolls-Rubble
M
F
P
P
P
P
P
P
P
F
M
P
P
P
P
P
M
Junction Creek
Pescar Loam
Midway Loam
Fortwingate Loam
Hesperus Loam
Connerton Loam
Big Blue Loam
Carracas-Sanchez
Outcrop
Fortwingate-Rock
Haploborolls Rubble
Valto Rock
P
F
P
P
P
P
M
P
M
M
P
P
P
P
Legend for Development Capability:
Poor (P): The soil type requires intensive and costly engineering design measures to overcome physical limitations.
For some types of facilities adequate engineering modifications may not be realistically feasible.
Fair (F): The soil type requires some special engineering design considerations to accommodate facility installation.
Most soil limitations can be resolved through appropriate design techniques.
Moderate The soil type requires compensating engineering designs to minimize soil limitations. Most constraints
(M): are readily resolved with standard techniques.
-------
Using these criteria, only six soils map units are considered as
unconstrained for septic tank-leach field systems: Connerton Loam,
Plome Loam, Clayburn Loam, Falfa Loam, Heldt Loam, and Nehar Loam.
Soils in the West Animas and Hermosa units are primarily loam
and river wash flanked by rubble and rock outcrops. The loamy soils
on both sides of U.S. Highway 550 in the eastern half of the West
Animas sub-area are probably satisfactory for septic tank-leach fields.
The Junction Creek valley consists of loam bordered by soil-rock
outcrops and badlands. The entire Junction Creek area is generally con-
strained for septic tank-leach fields except for small areas of Conner-
ton Loam east of Chapman Lake.
The Lightner Creek-Durango West area consists of loamy soils flanked
by soil-rock outcrops. A large area of Plome Loam, potentially suitable
for septic tank-leach fields, occurs in the southwestern corner of the
area on both sides of U.S. Highway 160; otherwise only a few scattered
areas have soils suitable for wastewater land disposal systems.
Loam, clay, and clayey-loam soils make up most of the Grandview,
Loma Linda, Air Park area. According to SCS characteristics, extensive
areas of Falfa Loam and Heldt Loam make most of this unit suitable for
septic tank-leach field systems. In practice, however, soil permea-
bilities in this area are often too slow to make land disposal of waste-
water practical.
Soils in the Florida Road area consist of loam and fluvaquents in
the flood plain areas and rock outcrops at the flood plain perimeter.
Most of the area of this unit is judged to be constrained for septic
tank-leach field systems.
Five soil types located within the Study Area have been designated
by the SCS as prime agricultural soils when irrigated. These include
Connerton loam (slope 1-3 percent), Humbarger loam (slope 3-6 percent),
Falfa loam (slope 1-3 percent), Heldt silty clay loam (slope 0-3 percent),
and Satanta loam (slope 1-3 percent). These soil types are located in
relatively small fragmented areas in the Animas Valley near Hermosa and
the West Animas areas and on the Florida Mesa near Grandview and Loma Linda.
62
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WATER RESOURCES
Surface Water Hydrology
The major surface waters in the Study Area are the Animas River,
Florida River, Lightner Creek, Hermosa Creek, and Junction Creek. The
Animas River is the major drainage with Hermosa, Junction, and Lightner
Creeks entering the river north and west of Durango. The Florida River
is tributary to the Animas River southeast of Durango. Streamflow is
southward into New Mexico. These drainages originate in steep, rugged,
heavily forested areas. Heavy thundershowers in the river and creek
drainages can cause severe local flooding. Portions of all of the
areas except the Florida Road area are included within the 100-year
flood plains for the Animas River, Lightner Creek, or Junction Creek.
The 100-year flood plains for the five areas are shown in Figures
4.7 through 4.11.
The Animas and Florida Rivers are domestic water supply sources
for the City of Durango. Water is diverted from the Florida River at
a point one mile west of the junction of Lemon Dam and Vallecito Res-
ervoir Road. Water is diverted from the Animas River near the 32nd
Street Bridge. The Florida River is currently the primary water supply
source for Durango.
Surface Water Quality
Water quality in the Animas River drainage has been affected by
many man-related activities. These include mining runoff, urbaniza-
tion, water diversions, irrigation return flows, and wastewater treat-
ment plant discharges (Allen, 1980). The Animas River above Baker's
Bridge has degraded water quality for pH, hardness, sulfates, turbidity,
conductivity and total dissolved solids. These parameters indicate that
nonpoint sources and mining activities are influencing the quality of
the Animas River upstream of the Study Area. The water quality of the
Animas River improves within the Study Area above Durango.
63
-------
FIGURE 4.7
ONE HUNDRED YEAR FLOODPLAIN
IN THE HERMOSA STUDY AREA
i
MILES
J
100-YEAR
FLOODPLAIN
-------
FIGURE 4.8
ONE HUNDRED YEAR FLOODPLAIN
IN THE JUNCTION CREEK STUDY AREA
_Roa_d_
,Ch»pm
\ ' L»k»
Durango
City
Limits
J.
I
100 - YEAR
FLOODPLAIN
1
MILES
-------
ONE HUNDRED YEAR FLOODPLAIN IN
THE LIGHTNER CREEK STUDY AREA
-------
100-YEAR
FL00DPLAIN
J-
U_S 160
L\_
10
12
Loma Linda
18
BU
6U
MILES
7U
8U •
ONE HUNDRED YEAR FLOODPLAIN IN THE
GRANDVIEW/LOMA LINDA STUDY AREA
¦n
M
o
¦c-
o
-------
FIGURE 4.11
ONE HUNDRED YEAR FLOODPLAIN
IN THE WEST ANIMAS STUDY AREA
100-YEAR
FLOODPLAIN
MILES
ENGINEERING-SCIENCE
-------
Water quality degradation occurs in the Animas River as it passes
through Durango and out of the Study Area. The river experiences sig-
nificant increases in hardness, specific conductivity, nutrient levels
(specifically a doubling in mean nitrate concentrations), total dis-
solved solids, sodium, chloride ions, and fecal coliform bacteria.
Changes in these parameters are indicative of the introduction of waste-
water discharges. Increases in concentrations of total coliforms
and selected heavy metals also occur in this area.
Water quality parameters of concern in the Florida River include
alkalinity, hardness, total dissolved solids, and conductivity, with
measureable amounts of ammonia. Water quality of the Florida River is
influenced primarily by reservoir releases, agricultural activities,
and nonpoint sources. The Florida River apparently has very little
effect on the water quality of the Animas River below the confluence.
Comparison of water qualities from both rivers above and below the
confluence indicated that there is no significant effect from the
Florida River.
Analysis of the existing data base indicates that Lightner Creek
is a primary source of degraded water for the Animas River. Concentrations
of pollutants generally increase downstream in Lightner Creek to its
confluence with the Animas River. It is probable that Lightner Creek
has an adverse impact on the Animas River's water quality for the
following parameters: temperature, total and fecal coliform concen-
trations, hardness, conductivity, turbidity, sulfates, and nutrients.
A study in 1974 indicated that the degraded quality of Lightner Creek
could probably be linked to nine wastewater dischargers located on the
creek (CDH, 1974). These dischargers have subsequently been eliminated.
Water quality sampling on the other tributaries (Junction Creek,
Hermosa Creek, and the Florida River) has been very restricted and
therefore provides very little analytical information for assessing
water quality problems.
69
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Ground Water Hydrology
In the central portion of La Plata County, ground water supplies
are available from sandstone, siltstone, shale, and unconsolidated
deposits such as clay, silt, sand, gravel, and boulders. Two basic
types of aquifers are present in the Study Area. Alluvial aquifers are
found in the present stream valleys, and bedrock aquifers are associated
with nearby slopes and upland sites.
The alluvial aquifers are thickest, as much as 30 feet, in the
Animas River Valley north of Durango. The deposits are absent or less
than 10 feet thick south of Durango. Alluvial aquifers in the Florida
River Valley are generally less than 20 feet thick. Yields from wells
completed in the alluvial aquifers average 15 gallons per minute because
of low permeability and limited saturated thickness (Brogden and Giles,
1976). Alluvial aquifers are recharged by infiltration of precipitation,
stream flow, and seepage from irrigation ditches. Ground water dis-
charges from these aquifers, in turn, contribute to base flow in the
streams.
Ground water movement in bedrock aquifers is generally southward
towards the San Juan River in New Mexico. Bedrock aquifer recharge is
accomplished by the infiltration of precipitation and by the movement
of ground water from nearby alluvial aquifers along a hydraulic gradient.
The water-yielding capabilities of bedrock aquifers varies according
to fracture porosity and permeability. Most reported well yields in
the Durango area range from less than 1 gallon per minute (hard shales
and limestone) to 10 gallons per minute (fractured shales and sandstone)
(Brogden and Giles, 1976).
Ground Water Quality
Analytical ground water quality data are sparse and incomplete for
the Study Area. Detailed data are available for 27 wells, primarily in
two areas, Florida Mesa and the Florida River Area east of Durango. Each well
was sampled once. No data are available for the Animas Valley near
Hermosa or for the area along the Animas River south of Durango.
70
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Ground water was analyzed for the following parameters: sodium,
heavy metals, chloride ions, nitrate-nitrite, and sporadically for
fluoride ions. The quality of ground water is quite variable and ranges
from poor to good. Ground water from most wells is highly mineralized
and requires some treatment. Chloride concentrations were well below
the domestic water supply standard in all wells tested except for one in
the Florida River Study Area. No standard currently exists for sodium
concentrations, but a former standard of 270 mg/1 can be used as a guideline.
Only two wells sampled exceed this value, and most have less than one-
third that concentration. Concentrations of both iron and manganese which
exceed the state standard were found in two widely spaced wells, and one
well in the Florida Mesa had a selenium concentration 15 times greater
than the state standard. Otherwise, dissolved heavy metals were not a
serious ground water problem. Four wells in the Florida River and Florida
Mesa areas showed nitrate plus nitrite concentrations at or above the
nitrate standard. It is unknown if these were the result-of natural or
man-induced contamination.
No fecal coliform counts exceeding the state raw water standard
were found in ground water samples. Total coliform counts of up to 500
per 100 milliliter were detected in springs sampled, but these springs
were subject to surface contamination and did not accurately reflect
ground water conditions.
BIOLOGICAL RESOURCES
Vegetation
Vegetation in the Rocky Mountain region is influenced by elevation,
exposure, temperature, soils, topography, and land use. Broad, gen-
eral vegetation zones are separated using altitude variation. Within
each zone smaller sub-units of vegetation can be identified and their
components inventoried.
The Study Area ranges in elevation from about 6,400 feet in the
Animas Valley south of Durango to about 8,800 feet. The principal
vegetation communities of the Study Area include Ponderosa pine
forest, pinyon-juniper woodland, mountain shrub, sagebrush, rip-
arian woodland, and croplands. Wetland and riparian areas are shown
on Figure 4.12.
71
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LOCATIONS OF WETLANDS
AND RIPARIAN AREAS
Ourango
-------
Vegetation inventories have been conducted in relation with the
Animas - La Plata Project. These inventories cover the plant com-
munities which are common to this Study Area. The large number of
variations in physical site conditions have produced a large variety
of habitats suitable for many different plant species. Vegetation
studies in the Study Area have identified about 557 species present.
Wildlife
Wildlife investigations conducted by the Colorado Division of
Wildlife and the Fort Lewis College Biology Department have Identified
50 species of mammals and 64 species of birds in the Durango area.
Forty-eight of these are considered game species by the Colorado Div-
ision of Wildlife. In addition, 22 species of reptiles and seven
species of amphibians have been found in the area.
Big game species in the area include mule deer, elk, bighorn
sheep, Rocky Mountain goat, black bear, and mountain lion. In gen-
eral, the major big game habitat is located north of Highway 160.
The area of highest concentration is the Animas River drainage north
and west of Durango. This area is designated as having critical
winter range, concentration areas, and fawning and calving areas.
Important areas for mule deer, elk, and bighorn sheep are shown in
Figures 4.13, 4.14, and 4.15 respectively. Upland game which occur
in the San Juan basin include wild turkey, blue grouse, ptarmigan,
and chukar partridge. The furbearer populations of the region
consists of beaver, muskrat, and historically, mink. All three of
these animals are water-oriented in their habitat requirements.
In addition, red and grey fox, and pine marten are found in the area.
Foxes occur in the rougher terrain adjacent to river bottoms and in
agricultural areas. The two major predator species are the coyote
and bobcat. Both occur throughout the region.
Four raptors of the area are the golden eagle, the bald eagle,
the osprey, and the peregrine falcon. Both the golden eagle and the
peregrine falcon nest on bluffs and ridges such as those in the Study
73
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DURANGO , COLORADO
MULE DEER HABITAT
~
CRITICAL WINTER RANGE
FAWNING AREA / WINTER RANGE
SALT LICK / WINTER RANGE
WINTER RANGE
SOURCE COLORAOO DIVISION OF
WILDLIFE
-------
DURANGO , COLORADO
ELK HABITAT
MILES
WINTER RANGE / CONCENTRATION AREA /
CALVING AREA
WINTER RANGE / CONCENTRATION AREA/
CALVING AREA / MINERAL LICK
CRITICAL WINTER RANGE
WINTER RANGE
WINTER RANGE / MIGRATION ROUTE
SOURCE COLORAOO DIVISION OF
WILDLIFE
160
-------
Ourongo
DURANGO , COLORADO
BIGHORN SHEEP HABITAT
o I
MILES
LIMIT OF LOCAL RANGE
IN ANIMAS VALLEY
SOURCE COLORADO DIVISION OF
WILOLIFE
Hwv 160
I
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Area. Ospreys are known to nest on reservoirs north of Durango. The
bald eagle is a common winter resident usually found in the vicinity
of streams and reservoirs. However, all of these birds are wide-
ranging predators and could be sighted anywhere in the Study Area.
Important nesting and/or hunting habitats for these species are
shown in Figures 4.16 through 4.18.
Aquatic Life
The Division of Wildlife has collected fish in the Animas River
from Baker's Bridge to the Stateline, and in the river's tributaries.
The following fish were collected in the Animas drainage: rainbow
trout, brown trout, brook trout, cutthroat trout, flannelmouth sucker,
bluehead mountain sucker, western white sucker, speckled dace, fresh-
water sculpin, and bullhead catfish. Several additional species of
fish have been planted or are known to be present within the drainage
but were not collected during the sampling program. These include
the Kokonee salmon, northern pike, channel catfish, largemouth bass,
yellow perch, bluegill, and green sunfish.
In the Animas River, the fish population estimates above Durango
are double those below Durango. This is a consequence of the differ-
ence in habitat between the two sections. The game fish estimates
for the Animas River are extremely low with respect to the size of the
river, and the non-game fish, populations are slightly higher than
what is considered normal. High game fish estimates in the Florida
River can be attributed to increased productivity below the reservoir.
The entire Animas drainage has been maintained as a rainbow
trout fishery for the past 20 years. This has been accomplished
through numerous catchable trout planted in the main river and
various tributaries each year. Harvest patterns for various trout
species removed from the Animas River and its tributaries are available
through the Division of Wildlife.
77
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DURANGO , COLORADO
OSPREY AND PEREGRINE
FALCON HABITAT
NESTING AREAS
| | HUNTING RANGE
P PEREGRINE FALCON
REPRODUCTION SITE
SOURCE > COLORADO DIV OF WILDLIFE
2 0 12 3
MILES
-------
MILES
~ HUNTING AREA
~ HUNTING AND NESTING AREA
| | SUPPLIMENTAL RANGE
SOURCE COLORADO DIVISION OF
WILDLIFE
DURANGO , COLORADO
BALD EAGLE HABITAT
-------
DURANGO , COLORADO
GOLDEN EAGLE HABITAT
CRITICAL NESTING AREAS
SOURCE COLORADO DIVISION OF
WILDLIFE
60
MILES
-------
Threatened and Endangered Species
One Federally endangered, one Federally threatened, and one
state endangered species potentially occur within the Study Area.
The peregrine falcon has been federally classified as endangered.
It is know to exist in the vicinity of the Study Area and one pair
of birds was observed west of Durango in 1974 and 1975. Recently
the U.S. Fish and Wildlife Service has introduced young captive-bred
peregrine falcons at the sites shown in Figure 4.16. Requirements
for suitable eyries are precipitous cliffs having several ledges,
potholes, or small caves in the cliff face to serve as suitable
nest sites. Hunting habitat includes areas which serve to concen-
trate or support prey species (primarily small-to-moderate-sized birds)
and must provide suitable prey exposure for aerial attacks. In the
Study Area the Animas River Valley, the Lightner Creek Valley, and
the Dry Fork area provide these criteria.
The bald eagle, Federally classified as threatened, is a common
winter resident of the area. The preferred habitat of this species
is along streams and at large lakes and reservoirs.
The lynx is classified as endangered by the state of Colorado.
It is a secretive predator primarily found in spruce-fir forests
above 9500 feet. Colorado Division of Wildlife distribution maps
indicate lynx may occur in the mountains north of Durango. These
animals have large ranges and may occasionally wander into the
Study Area.
Currently, there are no known threatened or endangered species
of plants in the Study Area.
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METEOROLOGY AND AIR QUALITY
Meteorology
A weather reporting station has been maintained at Durango since
1931 and is the source of information for the
istics of the area.
The Durango area has a relatively cool climate due to its eleva-
tion and its topographic orientation. The annual average daily
maximum temperature is 63.3°F and the annual average daily minimum
temperature is 29.1°F. Highest average monthly temperatures occur
during July and August (average monthly mean about 66°F) and the
lowest average monthly temperatures occur in December and January
(average monthly mean about 27°F). On an annual average basis,
approximately 209 days have minimum temperatures of 32°F or less;
only 12 days experience maximum temperatures of 90°F and above.
Between 1931 and 1973, temperature extremes ranged from a low of
-30°F recorded on January 13, 1963 to a high of 101°F recorded on
July 5, 1973.
Snow .occurs during every month except for June, July and August.
Typically the Durango area receives approximately 63 inches per year
with the greatest amounts occurring during December, January and
February. The average annual precipitation is 18.7 inches which is
typical of semi-arid environments. The driest months are June and
November and the wettest is August. Afternoon thundershowers during
the summer are characteristic of the area. The local topography
causes large variations in weather within short distances and occa-
sionally heavy thunderstorms cause damaging localized floods in small
watersheds. Precipitation generally increases and temperature de-
creases with increasing altitude, but these variations are modified
by the orientation of mountain slopes to the prevailing air currents
and the effect of the topographical features in creating local air
movements.
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Prevailing winds which are predominately from the west provide
cool temperatures during the summer and abundant moisture supplies
for snow during the winter. Cold arctic air masses flow down from
the north beginning in the late fall and continue into the spring.
Air Quality
Only limited quantitative information is available for air
quality in the Durango Valley. The only air sampling instrument
presently operated in the area is a high volume sampler in down-
town Durango. Routine measurements are taken for total suspended
solids (TSP), sulfates, and nitrates. Sulfate and nitrate concen-
trations are quite low - well below the State mean. However, TSP
concentrations are typically near the established standard of 75
mg/m3 (annual average). In 1979 annual geometric mean TSP con-
centrations exceeded the standard, while in the three previous
years they were 70, 70 and 71 mg/m3 respectively (Haig 1980, pers.
comm.). The Colorado Air Pollution Division anticipates continued
monitoring of TSP concentrations but not of sulfates and nitrates.
Air quality is generally considered good and there are no current
air quality problems except for TSP concentrations. The source(s)
of this material is unknown. Smoke from fireplaces and stoves is a
possible source of suspended solids. Particulates also may come from
mud carried to paved roads in the city during the winter and spring
from unpaved county roads and driveways. After drying on the pavement,
strong winds suspend the fine particles.
ENERGY RESOURCES
Energy resources in the Durango area include electricity, natural
gas, and coal. The predominant form of power is electrical energy,
which satisfies about 60 percent of the area's energy needs. There
are no significant electrical generating facilities in the Study Area;
power is purchased from the Upper Colorado Grid System. Demand for
electrical power is increasing at a rate of about seven to eight per-
cent per year, and anticipated demand for the next five years is
expected to increase about 20 percent (Murphy, 1980, pers. comm.).
Such growth is considered to be normal for the area. Recently con—
83
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structed electrical generating plants in Hayden, Montrose, and Craig
will satisfy present and near future electrical demands. Most of
the remaining non-transportation energy needs are satisfied by natural
gas. However, coal, a major mineral export, is becoming increasingly
important as a source of domestic heating.
TRANSPORTATION
Durango is the primary metropolitan center of the San Juan Basin.
It lies at the crossroads of U.S. Highways 550 and 160, and the Navajo
Trail Highway, all of which are all-weather roads. Public transpor-
tation in the area is provided by the Trailways Bus Company and
three commercial airline companies, Inter-Mountain Airways, Western
Airlines, and Frontier Airlines. The county has no rail freight
service.
However, there is a lack of major transportation links which
may impose some restrictions on the growth potential of the Durango
area and La Plata County. While good quality highways do traverse
the county, movement can be interrupted regularly during the winter
months. The Durango area does not lie on a major transportation
route connecting larger metropolitan areas; as a consequence, trans-
portation of goods into and out of Durango tends to be expensive.
The resulting high local costs of various goods may operate as a
disincentive for all but local resource-based industries to locate
in the area.
LAND USE PLANNING CONSIDERATIONS
There are three types of land use controls in the Durango area
of La Plata County: 1) the San Juan Basin Health Unit regulation
that lots plotted since 1972 in unsewered areas be at least three
acres in size; 2) the La Plata County Comprehensive Plan (LPCCP),
still in preparation, which includes "desired growth patterns" for
the areas around Durango; and 3) the Land and Resource Management
Plan (LRMP) which sets forth policies and performance standards
for development. The La Plata County Comprehensive Plan's desired
growth patterns designate areas that may be developed, with stipu-
84
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lated maximum densities ranging from an urban character of develop-
ment to one dwelling unit per forty acres. "Desired growth plans"
have been adopted for four of the six planning sectors in the
county. These desired growth plans are mandated for review every
year; thus, while they do define the current development guidelines,
the guidelines cannot be regarded as unalterable. Desired growth patterns
for the six Study Areas are shown in Figures 4.19 through A.23.
Undesignated (white) areas on these figures have a maximum allowable
density of one unit per 35 acres as designated in Colorado House Bill 1041.
Land use planning is a controversial issue in La Plata County.
The LRMP is presently the subject of a number of lawsuits and land
use decisions by locally elected officials have been the subject
of vigorous debate in the Study Areas. Therefore, while land use
planning factors for each area are discussed below, they should be
viewed in perspective with the controversial nature of these issues.
Hermosa
The recommended desired growth plan has an urban center at
Hermosa with residential development at densities ranging from one
living unit per acre to one unit per forty acres through the re-
mainder of the valley. Because the land use planning process and the
current land use regulations are being contested, it is not certain
whether they will be enforced in the future. If the regulations are
set aside, the active opposition of Animas Valley and Hermosa residents
to increased density in the area may have some effect on limiting the
amount of future development.
Junction Creek
The desired growth plan adopted in the Junction Creek area
allows residential development in the valley portions of the area
at maximum density of one unit per 10 acres.
Lightner Creek
The LPCCP desired growth plan designates residential develop-
ment in the Lightner Creek area at densities of one living unit per
three acres along Highway 160 between Durango and the Wildcat Can-
yon cutoff, one living unit per six acres along Highway 160 between
the Wildcat Canyon and Lightner Valley cutoffs, and one living unit
85
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FIGURE 4.19
DESIRED GROWTH PATTERNS
IN THE HERMOSA AREA
¥ LES
&
Hermosa 2
LEGEND
GROWTH CENTER
Urban Densities
GROWTH RING
Future Growth to Urban
Density
GROWTH FAN
1 Unit per 3 Acres
HIGHWAY RURAL
1 Unit per 5 Acres
RURAL RESIDENTIAL
1 Unit per 10 Acres
Y~7\ RURAL RESIDENTIAL
1 Unit per 10-40 Acre
-------
FIGURE 4.20
DESIRED GROWTH PATTERNS
IN THE JUNCTION CREEK AND
WEST ANIMAS AREAS
MILES
hapma
Mountain
LEGEND
GROWTH CENTER
Urban Densities
GROWTH RING
Future Growth to Urban
Density
GROWTH FAN
1 Unit per 3 Acres
Durango
City
Limits
HIGHWAY RURAL
1 Unit per 5 Acres
RURAL RESIDENTIAL
1 Unit per 10 Acres
\/[ RURAL RESIDENTIAL
Unit per 10-40 Acres
-------
DESIRED GROWTH PATTERNS
IN THE LIGHTNER CREEK / DURANGO WEST AREA
\
I
I
r,
Hwy_
MILES
LEGEND
GROWTH CENTER
Urban Densities
Tl GROWTH RING
Future Growth to Urban
Density
GROWTH FAN
1 Unit per 3 Acres
HIGHWAY RURAL
1 Unit per 5 Acres
RURAL RESIDENTIAL
1 Unit per 10 Acres
RURAL RESIDENTIAL
Unit per 10-40 Acres
-------
DESIRED GROWTH PATTERNS
IN THE GRANDVIEW/ LOMA LINDA STUDY AREA
Lomi Linda
r
MILES
GROWTH CENTER
Urban Densities
GROWTH RING
Future Growth to Urban
Density
GROWTH FAN
1 Unit per 3 Acres
HIGHWAY RURAL
1 Unit per 5 Acres
RURAL RESIDENTIAL
1 Unit per 10 Acres
T7[ RURAL RESIDENTIAL
u-u 1 Unit per 10-40 Acres
-------
DESIRED GROWTH PATTERNS
IN THE FLORIDA ROAD AREA
i
i— -
« ^
-------
per 10 acres further into the valley along County Road 207.
The plan shows part of Durango West as a growth center, defined
as "an established center that contains urban densities and uses".
The area around the growth center is planned for densities categorized
as growth ring (future development for urban densities and uses),
growth fan (one living unit per three acres) and highway
rural (one living unit per six acres). The latter category includes
only a small amount of land within the Study Area.
Grandview-Loma Linda
The adopted desired growth plan for the Grandview-Loma Linda
area provides two types of residential densities: 1) "highway
rural", with a density of one living unit per six acres, along
Highway 160, and 2) "rural residential", with one unit per 10
acres, along County Road 213. Portions of the area not included
in either of these categories are classified as "irrigated", a
designation which presumes agricultural use and makes development
more difficult.
Florida Road
In the adopted desired growth plan, a small portion of the west-
ern boundary of Florida Road is included in the growth ring that
surrounds the City of Durango. While no specific densities are
defined in that area, it is characterized as a "future development
area for urban uses and densities". The center portion of the area
is designated on the sector plan as a growth fan, with a maximum
density of one living unit per three acres. The eastern part of
the area and all other developable portions are designated for high-
way rural densities of one living unit per six acres.
West Animas
The proposed desired growth plan for the Animas Valley allows
residential development in the West Animas area at a density of one
living unit per acre.
Other Land Use Planning Considerations
Future population growth and land development in La Plata County
91
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will not be limited to the six areas defined in the 201 wastewater
facilities planning process. The Comprehensive Plan estimates that
2,800 additional dwelling units will-be located in Durango by the
year 2000. Because the City of Durango has few development sites
within its current boundaries, most of this development will occur
on unincorporated private lands near the City. The approved River-
side complex northeast of Durango will ultimately include 1,038
living units. Approximately 200 units are planned in Hillcrest
Mesa near Fort Lewis College, while about 100 units are planned
along Florida Road. There are several other development projects
in the area that are in various stages of planning.
Privately owned lands north of Hermosa along U. S. Highway 550
have recently experienced rapid development as both recreational
and residential areas. An additional 1,080 living units have
reportedly been approved for the Purgatory ski area located 10 miles
north of Hermosa. Tamarron, just south of Purgatory, plans to build
up to 400 units by 1990 (Neal, 1980, personal communication). Addi-
tional land is available along the U.S. Highway 550 corridor for per-
haps 200 high density dwelling units (Yates 1980, personal communication).
EXISTING AND PROJECTED POPULATIONS
EPA's policy for planning local and regional wastewater fac-
ilities is to use population forecasts that are consistent with
adopted state forecasts and national forecasts by state prepared
by the U.S. Department of Commerce, Bureau of Economic Analysis for
EPA in 1978. It is also the policy of EPA that wastewater facilities
plans be consistent with water quality management plans prepared under
Section 20 8 of the Clean Water Act, local land use plans and policies.
These policies are intended to avoid wasteful expenditures of public
funds which might result from oversizing or from construction of
wastewater facilities in areas not planned for or suitable for dev-
elopment. This EIS therefore presents data on recent and future
growth in La Plata County and discusses available population forecasts.
Existing Conditions
La Plata County, with a 1978 population of over 25,000, has grown
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steadily during the decade of the 1970's, showing an eight-year popu-
lation increase of 31 percent. Most of this growth took place outside
the City of Durango, which grew only nine percent over the same period.
Recent population and growth data for La Plata County and Durango are
summarized in Table 4.2. These statistics reflect permanent residents.
The overall level of-population for facility planning purposes is
higher because of part-time residents and tourists.
TABLE 4.2
RECENT POPULATION GROWTH IN
LA PLATA COUNTY AND DURANGO
Growth
1970 1978 1980 1970 to 19 78
La Plata County 19,199 25,101 31%
Durango City 10,333 11,245 9%
Durango as Proportion
of La Plata County 54% 45%
Source: U.S. Census of Population, 1970, 1978, and 1980.
The current population estimates of the six wastewater Study Areas
are summarized in Table 4.3.
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TABLE 4.3
POPULATION ESTIMATES OF THE STUDY AREAS
Study Area
Estimated 1980 Populations-
Percent
Hermosa
Junction Creek
Lightner Creek
Grandview-Loma Linda
Florida Road
West Animas
1700
250
960
1200
283
240
36.7
5.4
20.7
25.9
6.1
5.2
Total
4633
100.0
1. Source: Allen, 1980
Some of the forces encouraging growth in the recent past will con-
tinue to operate in the future, and new forces may also materialize.
The factors most likely to encourage future growth include increased
tourism, energy resource development (oil, gas, coal, geothermal),
and expanded irrigated agriculture. While these are factors that
are known to contribute to future growth in the Durango area, it is not
possible to determine how they may influence growth in the six areas
addressed in the Facilities Plan.
Population projections for the six development areas have been dev-
eloped under a base case condition. Base case conditions are equival-
ent to a no action alternative and assume that existing wastewater
management will not be an inducement to growth. The 20-year popula-
tion projections for the six sub-areas are presented in Table 4.4.
Low, medium, and high projections for each area are provided; the
basis for each is explained in a footnote to the table. If no fac-
ilities are built it is estimated that between 3,660 and 7,810 additional
residents will locate in the six Study Areas hy the end of the planning
period (Gruen & Gruen, 1980). Further discussion of population
projections is presented in Appendix A.
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TABLE 4.4
PROJECTED POPULATION INCREASES FOR DURANGO 201 STUDY AREAS
(Increases during 1980-2000 if no wastewater
facilities projects are implemented)
Estimated
1980 Projected Increases
Area
Total
Low
Medium
High
Hermosa^
1,700
750
1,275
1,500
2
Junction Creek
250
180
300
450
Lightner Creek/Durango West"^
960
1,950
3,315
3,700
Grandview/Loma Linda
1,200
420
600
900
Florida Road^
283
80
135
360
West Animas^
240
280
450
900
TOTAL
4,633
3,660
6,075
7,810
1Based on current approval of 550 unbuilt dwelling units: low projection
assumes 50% build-out; medium projection assumes 85% build-out; high
projection assumes 95% build—out. All projections assume 3.0 persons per
household.
2
Low projection assumed 3 dwelling units/year build-out; medium projection
assumes 5 dwelling units/year building-out; high projection assumes 30% of
503 planned units are built (note that only 287 units are currently
approved).
3
Based on current approval of 1,300 unbuilt units in Durango West: low pro-
jection assumes 50% build-out; medium projection assumes 85% build-out;
high projection assumes 95% build-out. All projections assume 3.0 persons
per household.
4
Low projection assumes 7 dwelling units/year build—out; medium projection
assumes 10 units/year build-out; high projection assumes 15 units/year
build-out.
\ow projection assumes build-out of 30% on existing vacant lot; medium
projection assumes build-out on 50% of existing vacant lots; high projec-
tion assumes build-out of 6 units/year.
Low projection based on completion and 100% occupancy of Waterfall Village;
medium projection based on completion and 100% occupancy of Waterfall
Village plus one similar project plus a few miscellaneous other units;
high projection based on completion and 100% occupancy of three Waterfall
Village-type developments.
Source: Gruen Gruen + Associates
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SOCIOECONOMIC CONSIDERATIONS
In addition to population growth projections and land use plan-
ning objectives, other socioeconomic considerations of importance
include land availability, land prices, existing local infrastructure,
and future regional and site-specific developments.
The relative prices of land in various areas play a part in det-
ermining where people live. Presented in Table 4.5 is a summary of
land prices in the six EIS Study Areas as of May, 1980. To some
extent, price differences reflect the presence or absence of amen-
ities; for example, Durango West, with lots priced at $12,000, has
paved streets with curbs and gutters, central water and central
sewage treatment. The availability of land for private ownership
establishes a geographic limit to the locations of future residen-
tial development, and the relative prices fpr land begin to suggest
the potential attractiveness and affordability of various areas
within the geographic limit.
Both the existing and proposed major residential developments
within the study areas are summarized in Table 4.6. In the Hermosa,
Lightner Creek, and Florida Road areas, there are no existing institu-
tional development constraints and the projects are progressing toward
completion. However, there are varying degrees of uncertainty assoc-
iated with some of the other proposed developments.
Proposed projects in the Junction Creek area have shown little
recent development activity and there are road access problems to
some areas. However, several other plans for additional condominium
complexes are being considered for Durango Estates, near Chapman Lake,
and other area.
The proposed new development for Grandview-Loma Linda is proba-
bly still considerably in the future. Development of the Animas
Airpark would occur following construction of a proposed shopping
center south of Durango and expansion of the industrial park.
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TABLE 4.5
COMPARATIVE SAMPLE LAND PRICES IN THE
EIS STUDY AREAS
Average
Price Lot/Parcel
Area Per Acre Per Lot Size
I. Hermosa
$12,000-14,000
0.5 to 6 acres
$8,000-10,000 0.5 acre
§8,000
23 acres
(1 parcel)
2. Junction Creek
$2,000-2,500
0.5 to 2 acres
3. Lightner Creek
(Too few
sales to generalize)
Durango West
$12,000 0.4 acre
4. Grandview-Loma Linda
$3,500®
unknown
5. Florida Road
$5,000-6,000
, unknown
$10,000 3 acres
6. West Animas
$6,000-7,000
unknown
aClose to Route 160 or other paved road.
bVery hilly terrain.
Source: Clayton Ebel, La Plata County Assessor, personal communication.
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TABLE 4.6
EXISTING AND PROPOSED MAJOR DEVELOPMENTS
IN THE STUDY AREAS
Major Developments by Area
Hermosa
Blue Sky
James Ranch
Hermosa Townhouses
Subtotal
Proposed Number of Units
200
288
110
598
Junction Creek
Durango Estates
Jacob's Cliffs
Sailing Hawks
Subtotal
407
180
16
503
Lightner Creek
Durango West
Grandview-Loma Linda
Animas Airpark
Florida Road
Florida River Estates
1200-1300
39
120
West Animas
Waterfall Village
90
Total
2500-2650
98
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The one pending major development in the West Animas area, Water-
fall Village, has been approved by the La Plata County Commissioners.
However, its development has been delayed as a result of the ban on
new package plants. Its ultimate development will depend on the
resolution of water quality problems in the Animas River above the
City of Durango's raw water intake points.
CULTURAL RESOURCES
Various Indian groups inhabited the area from early history.
The extensive archeological ruins of cliff dwelling tribes at Mesa
Verde, 36 miles southwest of Durango, are the most famous Indian
relics in the region. Subsequent Hispanic exploration and settlement
is reflected in the Spanish names of numerous local landmarks.
A mining boom hit the area in the mid-1800's following the dis-
covery of precious metals. Increased settlement and trade encouraged
the development of transportation systems. The Kansas to California
"Navajo Trail" passes through Durango. The Denver and Rio Grande
Narrow Gauge Railroad between Durango and Silverton is a Registered
National Historic Landmark. Several historic buildings from this
era are probably eligible for inclusion in the National Register of
Historic Places.
During the first half of the 20th century agriculture provided
a marginal to stable living for residents. During the 1950's discoveries
of energy and mineral resources expanded the population, but agriculture
provided the underlying stability to the economy. During this period
Durango also prospered from increases in tourism, recreation related
service industries, retail sales, and real estate expansion. Popula-
tion increases have continued into the 1970's because of a westward
movement of the nation's population and the increasing popularity of
the southwest.
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CHAPTER 5
ENVIRONMENTAL CONSEQUENCES
-------
CHAPTER 5
ENVIRONMENTAL CONSEQUENCES
This chapter presents information on the environmental consequences
of the wastewater management alternatives developed in the Facilities
Plan for each of the six Study Areas. All alternatives will be addressed
(as required under Section 1502.16 of the NEPA Regulations), although
emphasis will be given to the recommended alternative for each Study Area.
This chapter is organized into nine sections. The first six sections
present for each of the Study Areas a brief analysis of the significant
potential beneficial and adverse impacts of the wastewater management
alternatives, as well as possible mitigation measures. More detailed
information regarding impacts and mitigation is presented in Appendix B.
Information in the first seven sections may be regarded as- combined
discussions of two of the elements required by NEPA Section 102 (2)c:
environmental impacts of the alternatives, and any adverse environmental
effects which cannot be avoided. The remaining two elements of NEPA
Section 102 (2)c, (i.e., the relationship between local short-term uses
of man's environment and the maintenance of long-term productivity and
irreversible environmental changes of the proposed action) are addressed
in the remaining two sections of this chapter.
This organizational arrangement results in some repetition of impact
discussions common to two or more of the Study Areas. However, it facili-
tates review by Study Area residents of the impacts associated with
alternatives for each of the respective Study Areas and thereby is aimed
at facilitating public understanding of the environmental consequences
of decisions affecting each of the Study Areas and the planning area as
a whole. The detailed impact analysis for each Study Area presented in
Appendix B is organized by technical discipline to facilitate regulatory
agency review.
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WASTEWATER MANAGEMENT PLANS
The wastewater management strategies developed for each of the res-
pective Study Areas can be divided into three types: (1) No Action, (2)
Formation of Maintenance Districts, and (3) Sewers, either with a central
treatment facility or with connection to the City of Durango's system.
General environmental consequences associated with each of these alter-
native plans are discussed in the following paragraphs.
No Action
A major impact resulting from the No Action alternative is the con-
tinued threat to water quality and public health by continued reliance on
existing systems. The sanitary survey conducted in the spring of 1980
(Allen, 1980) indicated several existing package plants and some individual
on-site disposal systems were operating inadequately, had histories of
failures, and/or were expected to experience failures in the future.
Results of the sanitary survey are summarized in Table 5.1.
The threat to water quality and public health resulting from unit
failures and/or ground water contamination will continue to exist as long
as on-site disposal systems are used. The fact that the most recent water
quality study failed to conclusively document contamination does not
eliminate the potential for severe public health and/or water quality prob-
lems occurring in the future. Pathogens in inadequately treated waste-
waters are known to cause diseases such as typhoid, paratyphoid, bacillary
dysentery, cholera, poliomyelitis, and infectious hepatitus. Protection
of ground water resources is especially important since many of the areas
are dependent on ground water for domestic water supplies, e.g., Junction
Creek, Lightner Creek, Grandview/Loma Linda. Nutrients and suspended and
dissolved solids in inadequately treated wastewater can cause algal blooms,
degrade aesthetics, and be harmful to aquatic organisms.
Since the sanitary survey was conducted, many of the package plants
and individual units have been repaired, upgraded, and/or replaced. Also,
many systems which have a history of failures had been repaired and appeared
to be operating adequately at the time of the survey. In the many cases
in which the existing package plants or individual on-site systems appear
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TABLE 5.1
SANITARY SURVEY RESULTS1
Package Plants
and Multiple Customer Facilities Individual Systems
Units With2
3
Problems
Percent
Units
Percent
Units
or Potential
with
Units
with
with
Area
Examined
Problems
Problems
Examined
Problems
Problems
Hermosa
19
13
68
35
11
31
Junction Creek
1
1
100
25
5
20
Lightner Creek
5
5
100
13
2
23
Grandview/Loma Linda
18
11
56
37
7
19
Florida Road
1
1
100
25
3
12
West Animas
2
1
50
5
2
40
46
31
67
140
30
21
^Source: Allen 1980
2
This Includes systems with history of problems, needing
repairs,
emitting odors, and
for which
problems
anticipated because of
equipment, expected
loadings, or
location.
3
This includes systems needing repair, high ground water noted, history of problems, or for which problems
are anticipated.
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to provide an adequate method of disposing of wastewaters, increases in
ground water levels and/or population density could render such systems
unsuitable in the future.
Another consequence of the No Action alternative is the continued
requirement of septage handling. Septage can severely shock-load treat-
ment plants if not added to the waste stream in small amounts. Existing
septage volumes generated in the Study Area may be in excess of 6,000
gallons per day, which is enough volume to upset Durango's proposed treat-
ment plant should it be emptied directly into the facility.
The significance of the septage handling requirement is difficult
to assess given the overall hauled waste problem in the Study Area. Even
with implementation of sewers in Hermosa, Grandview/Loma Linda, and Junction
Creek, the hauled waste volume will not be significantly reduced. At
maximum, 40 multiple customer facilities and approximately 340 individual
systems would be retired. This results in a decrease of from 798,000
gallons per year (No Action) to 702,400 gallons per year (Sewers) or a
net reduction of 95,600 gallons per year (12 percent decrease) (Allen 1980).
Formation of Maintenance District
Implementation of a Maintenance District continues to rely on indivi-
dual on-site systems and package plants, but places the responsibility of
maintaining these systems with an appropriate governmental agency. Under
authority of this agency, existing systems would be upgraded as appropriate
and a monitoring program and reporting system would be established. The
Maintenance District envisioned for the individual Study Areas would involve
a one - or two-person staff. District purchases might include: septage
pumping equipment, chemical testing apparatus, maintenance tools, and
vehicles. Of primary importance in this alternative is the hiring of
a competent or trained operator to maintain the multiple customer facilities and
individual'plants.This would be a full-time position for an individual
certified by the Colorado State Department of Health with a Class C
Operators License minimum (Class B preferred). This employee would be
responsible for record keeping, sampling, and monitoring of plant opera-
tions, as well as routine pump, blower and system maintenance and clean-
up duties. The district would be embodied with authority for performance
of the following duties:
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1. Insure that the system which is suggested for use on a particular
parcel, or parcels, of property be the system best suited to the
waste flow, soil, slope, and drainage aspects of the property (or
properties), such that the system will properly treat and dispose
of the waste without presenting a health or water quality hazard.
2. Insure that during the installation of the system all due care is
given to the proper construction of the system so that the develop-
ment of a system's malfunction due to improper installation is
avoided during the projected operating life of the system.
3. Insure that during the operating life of the system, proper
maintenance of the system is achieved and optimal functioning
of the system is provided.
U. Insure that the total effects of the operations of the sum of
the systems within the boundaries of the district are not de-
grading the quality of the environment.
5. Insure that if a system malfunction occurs, the necessary powers
and capabilities for prompt correction of the malfunction are
at hand and applied.
Environmental impacts associated with this wastewater management plan
are similar to those described for the No Action alternative, except the
threat to public health by ground water contamination or by inadequately
treated wastewaters being released on the surface is considerably reduced
due to more frequent pumping of septage tanks, better operation of package
plants, and an expanded monitoring program.
An important impact resulting from implementation of a Maintenance
District is the financial burden imposed on owners of systems which are
presently operating adquately but who will be required to contribute
financially to the support of the District. In effect, owners who are
conscientiously maintaining their own systems will be required to subsidize
the maintenance of owners of faulty and poorly operated systems.
The Maintenance District alternative presented in the Facilities Plan
envisions separate Districts for each of the six Study Areas. The concept
of a Study Area-wide or county-wide District was eliminated early in the
facilities planning study even though such a concept might realize some
economies of scale for capital expenditures. Reasons for the elimination
of a Study Area-wide Maintenance District include the following:
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1. Inequitable division of capital improvement expenditures between
Study Areas and plants within Study Areas resulting from wide
variation in needs among plants to upgrade,
2. Many owners of existing package plants are licenced operators
who run plants themselves and thus are incurring no or minimal
operating costs but would be required to support a Maintenance
District operator, and
3. Nondischarging plants which presently have minimal maintenance
costs would be required to contribute to support of a Study
Area-wide Maintenance District.
Sewers
The single most important beneficial impact resulting from implementa-
tion of sewer alternatives is the enhanced safeguards to public health and
water quality. Elimination of individual on-site disposal systems and
many of the package plants in the Study Area will greatly reduce the threat
of contamination of the water resources in the area. It should be noted
that treatment facilities proposed in the Facility Plan will not remove
many of the chemical constituents in wastewater. Only tertiary treatment
will remove these nutrients. The major water quality improvements will
result from reduction of organic materials, other suspended and dissolved
solids, coliform bacteria, and other microbes.
One of the most important issues associated with installation of
sewers in the Study Area is the potential effect on growth rates and dis-
tribution patterns. Development patterns are restricted throughout the
Study Area by physical constraints such as flood plains and steep slopes.
In those areas suitable for development, institutional constraints in-
fluence growth patterns. For example, the Colorado Health Department
requires at least three acres of land per dwelling unit in unsewered areas
to accommodate on-site disposal systems. The availability of sewers may
relax this constraint on growth and may facilitate high density growth
and strip development along pipeline alignments. Desired growth patterns
have been adopted by the Planning Commission for four sectors (planning
regions) of the Study Area. However, land use ordinances are subject to
annual review. County planning documents recognize environmentally
sensitive areas but the County Commission mades decisions on a case-by-case
basis. Development in environmentally sensitive areas is not always
105
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prohibited. Thus the possibility exists that future growth in the
Study Area may adversely affect such sensitive resources as prime agri-
cultural land in the Hermosa, West Animas, and Grandview/Loma Linda
areas and wildlife resources in portions of the Study Area. No erosion
control ordinances are in effect in the Study Area, thus, mitigation
to growth related impacts will not be provided. In view of the competing
interest regarding land use management practices in the Study Area, the
issue of growth facilitation resulting from sewer installation is
considered significant.
The overall impact of sewers on population growth and land use change
in the six Study Areas is variable and depends, in part, on the natural
attractiveness of the areas in question. Without sewers, the development
potential and the relative attractiveness of each area would remain as they
are now. Durango West and the locations near the city but outside the 201/
EIS Study Area(Riverside, Hillcrest Mesa and the close-in areas on Florida
Road) would be the most probable high-growth areas, with capacity for
approximately 8,000 of the 20,000 new residents of La Plata County expected
between now and the end of the century. The Hermosa area, another attrac-
tive location, could take another 1,000 to 1,500 residents in the develop-
ment already planned. Edgemont Ranch would be another likely growth area
if and when it develops, with room for an estimated 1,500 residents as
well. Together, these areas would accommodate an estimated 11,000 new
residents, or almost 60 percent of the expected countywide population
increase.
The implementation of a sewer system in the Grandview-Loma Linda
Study Area would have the greatest potential impact on the future dis-
tribution of population and land use, because it would remove a major
development constraint there. The combination of wastewater facilities
and level, less expensive land (land prices could, however, be expected
to rise somewhat) would make the area an attractive one for new develop-
ment. If the desired growth pattern is changed to allow higher density
development, Grandview-Loma Linda could become a high-growth area. It
is not clear whether the increased development potential and attractiveness
in the area would result in a rearrangement of the 11,000 residents
106
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expected to locate in the Durango area of La Plata County or would Increase
the area's share of new county residents; Grandview-Loma Linda would be
a feasible alternative for residential location not only to Durango West
and Hermosa but also to Bayfield.
Implementation of projects in other areas would increase the develop-
ment potential but not relative attractiveness of those area. It there-
fore would result in a marginal amount of additional development - primarily
commercial along U. S. Highway 160 in the Lightner Creek area and Waterfall
Village in the West Animas area - but not a significant shift in the dis-
tribution of population growth.
The issue of who benefits versus who pays is considered significant
for sewering alternatives. Sewers will impose an economic burden on all
residents, including those who are presently using satisfactory systems
but who will be required to connect and/or contribute financially to the
new sewer system. The sewering alternatives are designed to correct
wastewater management problems caused by a minority of systems which are
operating inadequately. These problems are generally more acute with
package plant operations than with individual on-site units. Instead
of having owners of faulty systems paying for the repair/replacement of
their own systems, the sewering alternatives require all residents in
proposed service areas, many of which with adequate systems, to support
a plan to correct problems created by the minority.
An additional cost which may affect proposed service area residents
for alternatives which connect to the Durango System would be in the
form of higher taxes resulting from becoming annexed to the City.
Connection to the Durango System would most likely fall under the implied
consent rules of the City. Implementation of sewers, in this case,
may represent an agreement by the residents to be annexed to the City
at some future date by accepting City services.
Development within flood hazard areas is an important issue assoc-
iated with the Facilities Plan. The proposed treatment plant site for
Hermosa is located within the 100-year flood boundary. Also, proposed
sewer alignments traverse portions of the 100-year flood plain. Some
existing developments that will be served by the proposed facilities
107
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are located in flood hazard areas (e.g. Hermosa Meadows in Hermosa
and the Junction Creek Mobil Park in Junction Creek). Sewers could
facilitate development in flood hazard areas unless proper safeguards
are instituted. In that regard, EPA is considering the following
grant condition to the Facilities Plan:
The managing agency in conjunction with the other
local jurisdictions in the service area for this
project shall provide the EPA with documentation
that each local jurisdiction in the service area
has developed an effective program to control
development within the designated 100-year flood-
plain. At a minimum an effective program must
comply with the floodplain management standards
of the National Flood Insurance Program including
designation and regulation of the floodway. The
grantee and local jurisdictions may accept a sever-
age connection from any residential, commercial
or industrial structure located within a designated
100-year floodplain if the structure was in exis-
tence or was issued a local building permit prior
to the date of award of the Step 2 grant of the
project.
Installation of sewer lines and treatment facilities will result
in construction-related impacts (e.g. noise, dust, erosion hazard,
disruption of traffic flow). These impacts are temporary in nature
and can be mitigated easily by application of standard engineering
techniques. Another potential impact associated with construction
activities is the disruption and destruction of cultural/historical
resources that may be located within proposed construction areas.
This potential impact is considered significant in view of the rich
cultural heritage of the Study Area. In this regard, the following
grant condition is enacted by EPA:
108
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No payment in excess of 25 percent of the Step 2
grant shall be made prior to completion of a cultural/
historical resources survey that satisfies the
requirements of the construction grants program.
This condition is designed to provide early
identification of any conflicts of the plan with
these resources so that alternatives can be
investigated before a major commitment of Step
2 funds has been made.
Another significant consequence of implementing sewers is the net
reduction in electrical energy consumption. Consolidating wastewater
treatment into central treatment plants or to the Durango system
eliminates several package plant system, many of which are energy
intensive because of over-loading problems. The major reductions in
energy use occur in Hermosa, Junction Creek, and Grandview/Loma Linda
in which sewers would result in annual energy savings of 206,260 kwhr,
26,280 kwhr, and 28,000 kwhr, respectively.
HERMOSA
Recommended Alternative
The recommended alternative is a central treatment plant with one
of three different configurations of pipeline alignments serving diff-
erent portions of the Study Area. Issues, potential beneficial impacts
and adverse impacts resulting from implementation of this alternative
are presented in Tables 5.2 and 5.3.
Probably the single most important issue associated with the
recommended alternative is its effect on growth in the service area.
Development in the Hermosa area is constrained by both steep slopes
on the west and the Animas River flood plain on the east; nevertheless,
approximately 600 additional living units are currently planned for
the area. This development would nearly double the current populations.
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TABLE 5.2
POTENTIAL BENEFICIAL IMPACTS AND ISSUES ASSOCIATED WITH
RECOMMENDED ALTERNATIVE FOR HERMOSA AREA
Impacts/Issues
Enhances safeguards to public
health and to water quality.
Results in a net reduction
in energy usage.
Comments
Eliminates continued reliance on pac-
kage plants which in many cases are at,
near, or over design capability. Res-
ults of the package plant assessment
indicate that of the twelve plants sur-
veyed, seven are presently operating
adequately. However, prognosis is poor
for continued reliance on such systems.
Only three are considered sufficient to
provide good future service.
Allows sewer connections in those areas
employing on-site disposal systems that
are presently experiencing and/or are
expected to experience problems related
to the continued use of such systems.
The area is characterized by gravels
and high ground water. Of the 35 on-
site disposal systems observed in the
assessment, three have percolation rates
greater than 1 inch per 5 minutes and
nine note high ground water.
The existing treatment facilities col-
lectively consume about 277,730 kwhr
of electrical power annually. Of this
total, approximately 234,730 kwhr is
used by facilities that will be replaced
by the central treatment plant. Power
consumption by the proposed central treat-
ment plant is estimated at 28,470 kwhr
annually. Considering the energy needs
of the new plant and those of existing
systems not replaced by the new plant,
annual energy consumption is estimated
at 71,470 kwhr. This represents a 78
percent decrease in energy consumption
in the Hermosa area resulting from
implementation of the recommended alter-
native. In the proposed service area
alone the savings is 90 percent.
110
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TABLE 5.2 (continued)
Impacts/Issues
Results in greater reliability of
wastewater treatment capability in
Hermosa area for improved water
quality control.
Release present sewage treatment
facilities property to alternative
land uses, thereby improving local
aesthetic quality in areas near
these facilities.
Comments
Regional facility will have (1) better
equipment, (2) better and more uniform
operator capability, and (3) back-up
power supply, i.e., generators, to
assure continued operation in the event
of a power outage.
Collectively, approximately five acres
of land is presently occupied by exist-
ing treatment facilities. Abandonment
of systems replaced by the central
treatment facility will release 3.5
acres of land. The new treatment fa-
cility will occupy three acres of land.
The net gain in land is, thus, 0.5 acre.
Fifteen of the existing treatment facil-
ity sites will be replaced by one large
well-managed lagoon facility.
Ill
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TABLE 5.3
POTENTIAL ADVERSE IMPACTS AND ISSUES ASSOCIATED WITH
RECOMMENDED ALTERNATIVE FOR HERMOSA AREA
2.
Impacts/Issues
Treatment facility subject to flood
hazard. Most of the proposed serv-
ice area is outside the 100-year
flood plain. An exception is the
Hermosa Meadows package plant which
is vulnerable to flood damage.
Impose economic burden on resi-
dents who are presently using
satisfactory on-site disposal
systems but who will be required
to connect and/or contribute
financially to the Hermosa
area treatment system.
Comments
The proposed treatment plant site is
located within the boundaries of the
100-year flood plain. The 208 Plan
recommends against locating treatment
facilities in the flood zone. Federal
guidelines governing financing the con-
struction of facilities located in
flood plains may encumber funding
options.
The issue of who benefits versus who
pays is considered significant. The
recommended alternative is designed to
correct wastewater management problems
caused by a minority of systems which
are operating inadequately, namely, most
of the package plants and a few single-
family residences. Instead of having
owners of faulty systems paying for re-
pair/replacement of their own systems,
the recommended alternative requires
all residents in the proposed service
area, many of which with adequate sys-
tems, to support a plan to correct prob-
lems created by the minority. Conversely,
however, all residents of the Study Area
will benefit by the reduced hazard to
public health and water quality resulting
from the recommended plan. Estimated
costs are as follows:
Subalternative 1:
User Charge:
Tap fee:
Service hookup:
Subalternative 2:
User Charge:
Tap fee:
Service hookup:
$5.06-$8.48/month
$200-$550
$500-$1500
$5.42-$8.85/month
$200-$550
$500-$1500
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TABLE 5.3 (continued)
Impacts/Issues
3. Potential for water quality de-
gradation to Animas River via
effluent discharge.
4. May facilitate growth in the
Hermosa area with attendant
secondary impacts.
5. Results in the permanent conver-
sion of approximately three acres
of land.
6. May degrade aesthetic quality of
area immediately adjacent to pro-
posed site, e.g., odors, insect
nuisance, visual degradation.
7. May cause construction-related
impacts, e.g., noise, dust,
erosion hazard, and disruption of
traffic flow along pipeline
alignments.
Comments
Subalternative 3:
User charge: $4.72-$8.44/month
Tap fee: $200-$550
Service hookup: $500-$1500
The proposed outfall to discharge
effluent to the Animas River is loc-
ated 11.2 miles upstream from the City
of Durango's raw water intake for pub-
lic water supply. This intake is used
only during peak summer peiods, thus
at peak river flows and peak dilution
of any pollutants.
Present zoning ordinances require three
acres of land per dwelling unit in
order to accommodate an on-site dis-
posal system. The availability of
sewers may relax this constraint on
high density development. This is
especially important in view of the
annual review of land use ordinances
and competing interests regarding land
use management practices. The probability
of high density development occurring is
not" considered great since there pres-
ently exists a mechanism to accommodate
growth (i.e. aerated lagoons) were it
desired by local residents.
This includes the three acres for the
treatment lagoon plus areas necessary
for the three lift stations and other
auxiliary facilities, e.g., chlorinator.
This impact, when weighed against the
benefits of reclaiming land currently
occupied by existing package plants, is
considered insignificant.
Impacts are temporary and considered
minimal; disturbed areas along pipe-
line alignments will be restored to
pre-construction conditions after pro-
ject completed; most construction
activities in existing right-of-ways.
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TABLE 5.3 (continued)
Impacts/Issues
114
Comments
Treatment facility and
lift Stations; 3 acres
Subalternative 1:
3.4 miles alignment
5 highway crossings
-Trimble Lane (1)
-U.S. Hwy 550 (2)
-West Animas Road (1)
-Hermosa Meadows Road (1)
Subalternative 2;
4.5 miles alignment
1 stream crossing
-Hermosa Creek
6 highway crossings
-Trimble Lane (1)
-U.S. Hwy 550 (3)
-West Animas Road (1)
-Hermosa Meadows Road (1)
Subalternative 3:
6.0 miles alignment
1 stream crossing (as Subalt. 2)
6 highway crossings (as Subalt. 2)
-------
Water is available from the Animas Water Company, septic tanks function
adequately and roads are average for the Durango area. There is a ban on
additional package plants pending resolution of a water quality problem
downstream in the Animas River, but new aerated lagoon systems are per-
mitted for developments with lots too small for septic tanks. The de-
sired growth pattern calls for densities ranging from urban, at Hermosa cen-
ter, to one unit per 40 acres.
If a central wastewater treatment plant is built at Trimble Lane to
serve Subarea la (the southern portion of the Study Area), it would have
little impact on development potential in the area because development
too dense for septic systems is already permitted where aerated lagoon treat-
ment systems are installed. Development potential could change if the
presence of a treatment plant creates additional political pressures to
allow greater residential density than is currently permitted by the
desired growth plan.
Construction of a central treatment plant would also have little
effect on the desirability of new development in the Hermosa Study Area.
The area has historically been considered attractive and has no conditions
that currently inhibit development. Conflicts about growth among area
residents may become sharper over time, however, especially if the
density limit imposed by the minimum three-acre lot for septic require-
ment is removed. It should be noted that the area's electorate voted
in June 1980 to reject establishment of a Hermosa Sanitation District,
which would have been a first step toward enabling construction of a
central treatment plant.
Another important issue is the potential for water quality degradation
to the Animas River resulting from effluent discharge. The proposed
outfall is located 11.2 miles upstream from the City of Durango's raw
water intake for public water supply. The proposed facility, while
removing BOD, solids, and coliform bacteria, will not remove nutrients
115
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such as nitrogen and phosphorus which are important to algal growth.
Only tertiary treatment would eliminate these nutrients. The impact of
this nutrient discharge to the river is considered negligible in view
of the small amount of discharge relative to the dilution volume of the
river. Durango's raw water intake is used only during peak summer
periods, thus at peak river flows and peak dilution of any pollutants.
Possible mitigation measures for adverse impacts are summarized
in Table 5.4.
Other Alternatives
Environmental impact analyses were conducted on three other altern-
ative wastewater management plans for the Hermosa area. These alternative
include:
1. Establishment of a Maintenance District,
2. Collection and Interceptor lines to connect with Durango facility,
and
3. No Action.
Impacts associated with these alternatives are presented in Table 5.5.
An additional alternative addressed in the Facilities Plan (i.e., exten-
sion of sewer lines into Baker's Bridge area) was eliminated from consid-
eration early in the facilities planning study as not cost-effective
and, thus, is not analyzed in the impact assessment.
JUNCTION CREEK
Recommended Alternative
The recommended alternative for the Junction Creek area involves
installing an inceptor to connect with the City of Durango System.
Issues, potential beneficial impacts and adverse impacts associated
with the recommended alternative are presented in Tables 5.6 and 5.7.
The effect of the recommended alternative on growth is considered
an important issue. There are currently about 78 living units in the
Junction Creek Study Area. There are two approved subdivisions which
together would contain 587 units at ultimate development. One of these
116
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TABLE 5.4
POSSIBLE MITIGATION MEASURES FOR POTENTIAL ADVERSE IMPACTS
ASSOCIATED WITH RECOMMENDED ALTERNATIVE FOR
HERMOSA AREA
Impact
Flood hazard.
Mitigation
The potential hazard from flooding was
considered in the site selection pro-
cess and design of the facility. Flood
level studies have been conducted and
protection against a 100-year flood will
be provided. Adherence to Federal guide-
lines, including a grant condition pro-
hibiting taps from new development in the
flood plain and adequate flood proofing
of the treatment plant will reduce
the flood hazard.
Water quality degradation.
Growth facilitation.
Aesthetics degradation at new
treatment facility.
Construction-related impacts.
The proposed treatment facility will be
designed to provide effluent of suffi-
cient quality to meet state and Federal
criteria for protection of water quality.
Strict adherence to land use plans and
zoning ordinances designed to provide
orderly, well-managed growth will pre-
vent uncontrolled development facili-
tated by the proposed alternative.
Adherence to land yse plans and ordinances
is a local matter, however, and EPA has
limited authority over decisions made
at the discretion of local authorities.
The treatment facility plant will be
designed and operated in a manner to
prevent odor and insect nuisance from
becoming a problem. Landscaping the
proposed facility to blend in with the
surrounding environment will mitigate
against visual degradation. The lagoon
system may enhance local aesthetics if
landscaped and managed for desired goals
such as waterfowl use, etc.
Standard engineering practice will keep
construction related impacts to a min-
inum. Excavated areas will be kept to
the minimum required for safe, efficient
operation of equipment. Existing rights-
of-way will be used where possible.
Disturbed areas along alignments will
be restored.
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TABLE 5.5
POTENTIAL IMPACTS ASSOCIATED WITH ALTERNATIVES TO
THE RECOMMENDED PLAN FOR THE HERMOSA AREA
MAINTENANCE DISTRICT
Beneficial Impacts
Lessening of threat to public
health and water quality by
upgrading faulty on-site dis-
posal systems and package
plants. Improved operation
of package plants by provid-
ing a licensed Class C or
better operator.
Adverse Impacts
1. Continued threat to public health
and water quality associated with
on-site disposal and reliance on
small package plants that are sub-
ject to maintenance/operation prob-
lems. This threat will persist as
long as such systems are used. In
most cases, these methods of treat-
ment and disposal appear adequate
at present; however, increases in
ground water levels and/or popula-
tion density could render existing
systems unsuitable.
2. Monthly user costs to support Dis-
trict administration, equipment,
and staff are more than double the
costs of the recommended plan. Pre-
liminary estimate is $19.94/month
assuming 480 users.
3. Continued septage handling require-
ment.
COLLECTION AND INTERCEPTOR LINES TO CONNECT WITH DURANGO FACILITY
Beneficial Impacts
Enhances safeguards to public
health and to water quality by
eliminating reliance on small
package plants and on-site
disposal systems.
2.
Releases present package plant
property to alternative land
uses, thereby improving local
aesthetic quality in areas
near these facilities.
Adverse Impacts
1. Imposes economic burden on resi-
dents who are presently using
satisfactory on-site disposal
systems but who will be required
to connect and/or contribute
financially to new conveyance sys-
tem and capacity of Durango treat-
ment plant; preliminary estimate
is $18.99/month assuming 480 users.
2. May facilitate growth and strip
development in Animas Valley with
attendent secondary impacts.
118
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TABLE 5.5 (continued)
Beneficial Impacts
3. Results in net reduction in
energy usage.
Adverse Impacts
3. Construction-related impacts,
e.g., noise, dust, erosion haz-
ard, disruption of traffic flow
among pipeline alignment.
NO ACTION
Beneficial Impacts
1. No additional economic burden
to residents except those
associated with upgrading or
replacing failing systems.
Adverse Impacts
1. Continued threat to public health
and water quality associated with
on-site disposal and reliance on
small package plants that are sub-
ject to maintenance/operations
problems. This threat will per-
sist as long as such systems are
used. In most cases, these methods
of treatment and disposal appear
adequate at present; however, in-
creases in ground water levels
and/or population density could
render existing systems unsuitable.
2. Continued septage handling require-
ments.
119
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has a commitment from the City of Durango for wastewater treatment, but
that commitment would use up all remaining capacity in the sewer line
serving the area. Other development constraints in the area include a
limited amount of water, few paved roads, steep slopes on the northern
and western edges of the area and the presence of Chapman Lake, seasonally
replenished by snowmelt, in the center. The Federal Bureau of Land Manage-
ment owns a sizable amount of land in the eastern portion of the area,
on Animas City Mountain. Area residents are opposed to significant addi-
tional development.
The extension of a sewer line to Junction Creek Mobile Home Park
would marginally increase development potential in the area it serves,
because there is only a relatively small amount of land available for
development in that portion of the Study Area. The scarcity of water
in Junction Creek will remain as a constraint on development potential,
as will the slope hazards in the north and west. The project would, how-
ever, remove an existing moratorium on development that would hook into
the city sewer system.
The installation of a sewer line up to the mobile home park is also
unlikely to increase the Study Area's relative attractiveness for future
development. More important factors, which will remain to inhibit future
growth, are the area's relative seclusion, high altitude (which brings
with it more severe winters than in the valley below) and lack of paved
roads. The one subdivision in the area with central sewer (Jacob's Cliffs)
has not experienced a significant amount of development.
Possible mitigation measures for adverse impacts are summarized in
Table 5.8.
Other Alternatives
Environmental impact analyses were conducted on five other alternative
wastewater management plans for the Junction Creek area. These alternatives
include:
1. Collection and interceptor lines for all of Junction Creek
drainage to connect with Durango system,
2. Collection and interceptor lines to West Animas Sanitation
District via Spring Creek,
120
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TABLE 5.6
POTENTIAL BENEFICIAL IMPACTS AND ISSUES ASSOCIATED WITH THE
RECOMMENDED ALTERNATIVE FOR JUNCTION CREEK AREA
Impacts/Issues
1. Enhances safeguards to public
health and to water quality.
Comments
Eliminates continued reliance on the
one package plant in the area that
has a history of maintenance problems.
Discharge of this plant is to Junction
Creek and has resulted in water quality
and aesthetic degradation seasonally,
especially during periods of low flow.
Eliminates reliance on on-site disposal
systems. Of the 25 observed in assess-
ment, four are probably inadequate be-
cause of high percolation rate, high
ground water, and malfunctioning equip-
ment. Three rely on evapotransporta-
tion.
2. Results in a net reduction in
energy usage.
The package plant currently requires
24-hour blower operation at a sub-
stantial electric cost because of
over capacity/maintenance problems.
The plant currently uses 26,280 kwhr
of electrical energy annually. The
Increased energy costs to the Durango
facility for treatment of wastewater
from Junction Creek are considered
negligible. Therefore, the net an-
nual energy savings is approximately
26,280 kwhr.
121
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TABLE 5.7
POTENTIAL ADVERSE IMPACTS AND ISSUES ASSOCIATED WITH
RECOMMENDED ALTERNATIVE FOR JUNCTION CREEK AREA
Impacts/Issues
Impose economic burden on resi-
dents who are presently using
satisfactory on-site disposal
systems but who will be required
to connect and/or contribute
financially to sewer line and
capacity rights in Durango plant.
May facilitate growth in Junction
Creek area.
Comments
The issue of who benefits versus who
pays is considered significant. The
recommended alternative is designed
to correct wastewater management prob-
lems caused primarily by the one package
plant in the study area which serves 38
mobile homes. Residents in five private
homes would be required to connect to
and to contribute financially to the
project. Estimated costs are as follows:
User charge:
Tap fee:
Service hookup:
$6.81/month
0-$100
0-$400
An additional cost which may affect res-
idents of the proposed service area would
be in the form of higher taxes result-
ing from becoming annexed to the City
of Durango. The recommended alterna-
tive would most likely fall under the
implied consent rules of the City of
Durango. Implementation of this al-
ternative may, in effect, represent
an agreement by the residents to be
annexed to the City at some future
date by accepting City services.
Current zoning is one dwelling unit
per three acres. This density is due,
in large part, to restrictions imposed
by on-site disposal systems. The
availability of sewers may relax this
constraint on high density development.
This is especially important in view
of the fact that land use plans are
reviewed annually by the County and
could be modified to accommodate more
growth. The likelihood of rapid growth
occurring given the present conditions
and attitudes in the Study Area is
considered minimal.
122
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TABLE 5.7 (continued)
Impacts/Issues
3. The facility would provide service
to mobile homes located within the
100-year flood plain.
4. Construction-related impacts, e.g.
noise, dust, erosion hazard, dis-
ruption of traffic flow along
pipeline alignment.
Comment s
Mobile homes are especially vulnerable
to flood damage and pose a hazard to
others if they are carried away by
flood waters.
Includes 2,500 lineal feet of pipe-
line, part of which is replacement
of existing sewer line within Durango
City limits.
123
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3. Formation of a Maintenance District,
4. Central Wastewater Treatment Facility, and
5. No Action.
Impacts associated with these alternatives are presented in Table 5.9.
LIGHTNER CREEK
Recommended Alternative
The recommended alternative for the Lightner Creek area involves
installing an interceptor to connect with the existing Lightner Creek
Sanitation District interceptor and to secure treatment capacity at the
Durango treatment facility. Four different interceptor systems were
considered, each serving a different portion of the Study Area. Option
"a" in the Facilities Plan was selected. It consists of installing an
interceptor from the Lightner Creek Sanitation District line along U.S.
Highway 160 to Wildcat Canyon Road. Issues, potential beneficial impacts,
adverse impacts, and mitigation measures associated with the recommended
alternative are presented in Table 5.10.
The recommended alternative may influence growth but the degree of
growth is not expected to be significant. The Lightner Creek area is
divided into two distinct subareas: Lightner Creek, which is exten-
sively developed into a variety of residential and tourist-oriented
uses, and Durango West, which is a newly-developing, primarily residential
subdivision. Durango West is expected to be a major growth area because
it has central water and sewer and paved roads, and is only a short driving
distance from the city along a major highway. Future development in
Lightner Creek will be limited by the lack of available large parcels
of undeveloped land and by steep slopes on both sides of U. S. Highway
160 and County Road 207.
Extension of the LCSD sewer westward along U. S. Highway 160 to the
Wildcat Canyon cutoff would both accommodate existing development and
create potential for additional development. This potential for addi-
tional development would be small, however, because the steep slopes
on both sides of the highway severely limit the amount of available
land. Further, new development is likely to be commercial (including
tourist-oriented) in nature rather than residential because of the
124
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TABLE 5.8
POSSIBLE MITIGATION MEASURES FOR POTENTIAL ADVERSE IMPACTS
ASSOCIATED WITH RECOMMENDED ALTERNATIVE FOR
JUNCTION CREEK AREA
Impact
Growth facilitation
Mitigation
Strict adherence of local officials to
land use plans and zoning ordinances
designed to provide orderly well-
managed growth would prevent uncon-
trolled development facilitated by
the proposed alternative. Adherence
to land use plans and options is a local
matter, however, and EPA has little
authority over decisions made at the
descretion of local authorities.
Flood hazard
Mobile homes, by virtue of their
mobility, are well-suited to relocation
to less hazardous areas. EPA recommends
that mobile home Dark owners and local
officials formulate a olan to relocate
any mobile homes that may exist in the
flood hazard area as defined by the
Federal Emergency Management Agency,
and provide flood protection for those
that lie within that portion of the
100-year flood plain that lies outside
the flood hazard area.
Construction related impacts
Standard engineering practice will
keep construction related impacts to
a minimum. Excavated areas will be
kept to the minimum required for safe,
efficient operation of equipment.
Existing rights-of-way will be used
where possible to minimize disturbance
to undeveloped areas. Disturbed areas
along the alignment will be restored
to preconstruction conditions.
125
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TABLE 5.9
POTENTIAL IMPACTS ASSOCIATED WITH ALTERNATIVES TO
THE RECOMMENDED PLAN FOR THE
JUNCTION CREEK AREA
SEWERS TO DURANGO WEST AND ALONG JUNCTION CREEK
Beneficial Impacts
1. Enhances safeguards to public
health and to water quality by
eliminating reliance on small
package plant and on-site dis-
posal systems.
Adverse Impacts
1. Imposes economic burden on resi-
dents who are presently using
satisfactory on-site disposal sys-
tems but who will be required to
connect and/or contribute finan-
cially to sewer line and capacity
rights in Durango plant. Prelim-
inary estimates for monthly user
fees range from $8.20 to $24.30
depending on the number of users.
These costs are higher than those
associated with the recommended
alternative because more sewer lines
are required.
2. Results in a net reduction in
energy usage.
2. May facilitate more extensive growth
in Junction Creek area than the
recommended or no action plans.
Given the existing physical con-
straints and the prevailing atti-
tudes of people in the Study Area,
major increases in growth are not
anticipated.
3. Flood hazard same as described
in Table 5.8.
4. Construction-related impacts, e.g.
noise, dust, erosion hazard, dis-
ruption of traffic flow along pipe-
line alignment.
COLLECTION AND INTERCEPTOR LINES TO WEST ANIMAS SANITATION DISTRICT
VIA SPRING CREEK
Beneficial Impacts Adverse Impacts
1. Affords some benefit to public 1. Does not include existing package
126
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TABLE 5.9 (continued)
Beneficial Impacts
health and water quality by
eliminating individual on-site
disposal systems in service
area. In most cases, these
methods of treatment and dis-
posal appear adequate at present;
however, increases in ground
water levels and/or population
density would render existing
systems unsuitable.
Adverse Impacts
plant, and thus, does not correct
existing wastewater handling
problem in Study Area.
2. Imposes economic burden on resi-
dents who are presently using
satisfactory on-site disposal
systems but who will be required
to connect and/or contribute
financially to new conveyance
system to the West Animas Sani-
tation District and capacity in
the Durango treatment plant.
Preliminary monthly user fee
estimates range from $11.60 to
$38.00 depending on number of
users.
3. May facilitate growth in Junction
Creek and Chapman Lake areas.
4. Results in major construction ac-
tivities in undisturbed, steep
slope areas north of Animas City
Mountain. This area is considered
critical winter range for mule
deer and winter range, concentra-
tion area, and calving area for
elk.
5. Construction-related impacts, e.g.
noise, dust, erosion hazard, dis-
ruption of traffic flow.
MAINTENANCE DISTRICT
Beneficial Impacts
1. Lessening of threat to public
health and water quality by up-
grading faulty on-site disposal
systems and package plant. Im-
proved operation of package plant
by providing a licensed Class C
or better operator.
Adverse Impacts
1. Continued threat to public health
and water quality associated with
on-site disposal and reliance on
small package plants that are sub-
ject to maintenance/operation prob-
lems. This threat will persist as
long as such systems are used; how-
ever, it is less than that with the
No Action alternative. In most
127
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TABLE 5.9 (continued)
Beneficial Impacts
Adverse Impacts
cases, these methods of treat-
ment and disposal appear adequate
at present; however, increases in
ground water levels and/or population
density could render existing sys-
tems unsuitable.
2. High monthly user costs to support
upgrading existing plants, District
administration, equipment, and staff.
Preliminary estimate is $11.32/month.
3. Continued septage handling require-
ment.
CENTRAL TREATMENT PLANT AT CHAPMAN LAKE
Beneficial Impacts
1. Affords some benefit to public
health and water quality by
eliminating individual on-
site disposal systems in ser-
vice area. In most cases,
these systems appear adequate
at present; however, increases
in ground water levels and/or
population density would render
existing systems unsuitable.
Adverse Impacts
1. Does not include existing package
plant and, thus, does not correct
existing wastewater handling prob-
lem in Study Area.
2. Imposes economic burden on resi-
dents who are presently using
satisfactory on-site disposal sys-
tems' but who will be required to
connect and/or contribute finan-
cially to new conveyance system
and treatment plant; preliminary
cost estimate ranges from $3.85/
month (350 users) to $13.48/month
(100 users).
3. Depending on size of the plant, it
may facilitate growth in Junction
Creek and Chapman Lake areas with
attendant secondary impacts.
4. Results in major construction ac-
tivities and development in gen-
erally undisturbed area near Chap-
man Lake. This area is considered
critical winter range for mule
deer and winter range, concentra-
tion area, and calving area for elk.
128
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TABLE 5.9 (continued)
Beneficial Impacts Adverse Impacts
5. Construction-related impacts, e.g.,
noise, dust, erosion hazard, dis-
ruption of traffic flow.
NO ACTION
Beneficial Impacts
1. No additional economic burden
to residents except those
associated with upgrading or
replacing failing systems.
Adverse Impacts
1. Continued threat to public health
and water quality associated with
on-site disposal and reliance on
small package plants that are sub-
ject to maintenance/operations
problems. This threat will per-
sist as long as such systems are
used. In most cases, these methods
of treatment and disposal appear
adequate at present; however, in-
creases in ground water levels
and/or population density could
render existing systems unsuitable.
2. Continued septage handling require-
ment.
129
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TABLE 5.10
POTENTIAL BENEFICIAL IMPACTS, ADVERSE IMPACTS, ISSUES, AND
POSSIBLE MITIGATION MEASURES ASSOCIATED WITH RECOMMENDED
ALTERNATIVES FOR LIGHTNER CREEK AREA
BENEFICIAL IMPACTS/ISSUES
Impacts
Enhances safeguards to public
health and to water quality.
Comments
Eliminates one package plant (Swiss
Chalet Motel) and several on-site
disposal systems. The package plant
appeared to be operating adequately
when inspected but has a high poten-
tial of inadequate operation during
its peak loading during the tourist
season. Colorado Health Department
recommends connecting this package
plant to the Lightner Creek Sanita-
tion District System.
ADVERSE IMPACTS/ISSUES
Impacts
1. Imposes economic burden on
residents who are presently
using satisfactory on-site
disposal systems but who will
be required to connect and/or
contribute financially to sewer
line construction and capacity
rights in the Lightner Creek
Sanitation District System.
Comments
The issue of who benefits versus who
pays is considered important. All
residents would benefit from the
reduced threat to water quality and
public health. However, the recommen-
ded alternative is designed to correct
anticipated wastewater management
problems from one package plant. In-
stead of having the owners of this
facility pay for repairs and/or up-
grade ,the recommended alternative
requires all residents in the proposed
service area, many of which have ade-
quate systems, to support a plan to
correct problems associated with the
one package plant. Estimated costs for
users:
Monthly user fee: $17.50-$25.50
Tap fee: $405-$l,229
An additional cost which may affect
proposed service area residents would
be in the form of higher taxes result-
ing from becoming annexed to the City
of Durango. The recommended alter-
native would most likely fall under
130
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TABLE 5.10 (continued)
the implied Consent rules of the City
of Durango. Implementation of this
alternative may, in effect, represent
an agreement by the residents to be
annexed to the City at some future
date by accepting City services.
Could facilitate high density
residential development in
service area with attendant
secondary impacts.
Present zoning ordinances require three
acres of land per dwelling unit in
order to accommodate an on-site dis-
posal system. Developable land is
generally confined to a narrow strip
traversing the valley because of
flood hazard potential and steep
slopes. The availability of sewers
may relax constraints on high density
development. This is especially
important in view of the annual re-
view of land use ordinances and com-
peting interests regarding land use
management practices.
Construction-related impacts,
e.g., noise, dust, erosion
hazard, disruption of traffic
flow along alignment.
Involves 1,700 linear feet of right-
of-way along US 160 and one street
crossing.
MITIGATION MEASURES
Impacts
1. Growth facilitation
Strict adherence of local officials
to land use plans and zoning ordinances
designed to provide orderly, well-
managed growth may prevent uncontrolled
high density development facilitated
by the proposed alternative. Adher-
ence to land use plans and options is
a local matter, however, and EPA has
little authority over decisions made at
the descretion of local authorities.
2. Construction-related impacts
Standard engineering practice will keep
construction-related impacts to a min-
imum. Excavated areas will be kept
to the minimum required for safe, effici-
ent operation of equipment. Existing
rights-of-way will be used. Disturbed
areas along alignments will be restored
after construction.
131
-------
character of existing uses and the fact that the highway is a major
thoroughfare.
Improved safeguards to water quality in Lightner Creek resulting
from the project are considered important because domestic wells are
located in the floodplain and in some cases, within 100 feet of the creek
(e.g. at Lightner Creek Mobile Home Park and Safari Lodge). Also, the
E. B. Howard Condominiums obtain domestic water directly from the creek.
Other Alternatives
Environmental impact analyses were conducted on three other alter-
native wastewater management plans for the Lightner Creek area. These
alternatives include:
1. Formation of a Maintenance District,
2. Central Wastewater treatment facility, and
3. No Action.
Impacts associated with these alternatives are presented in Table 5.11.
GRANDVIEW/LOMA LINDA
Recommended Alternative
The results of the engineering analysis presented in the Facilities
Plan concluded that the most desirable, cost effective method of providing
wastewater management to this Study Area would be to divide the area into
two subareas and provide separate collection, conveyance, and treatment
systems for each.
For the Grandview and Pinon Acres areas, the recommended alternative
involves the construction of a central aerated lagoon with associated
interceptors and collectors. A separate but similar system would be
built in the Loma Linda and Falfa areas. In both cases, local sani-
tation districts would be formed to administer wastewater management
activities within their respective service areas. Issues, potential ben-
eficial impacts and adverse impacts resulting from implementation of
these alternatives are presented in Tables 5.12 and 5.13.
The Grandview/Loma Linda area is probably the most vulnerable to
growth and development pressures of the six Study Areas. It has the
greatest amount of level, physically unconstrained land of the six
Study Areas. Water is available from wells but local roads are not
paved and soils are poorly suited to septic tanks. It is farther from
Durango than most of the other Study Areas.
132
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TABLE 5.11
POTENTIAL IMPACTS ASSOCIATED WITH ALTERNATIVES TO
RECOMMENDED PLAN FOR THE LIGHTNER CREEK AREA
MAINTENANCE DISTRICT
Beneficial Impacts
1. Lessening of threat to public health
and water quality by upgrading
faulty on-site disposal systems and
package plants. Improved operation
of package plants by providing a
licensed Class C or better opera-
tor.
Adverse Impacts
1. Continued threat to public health
and water quality associated with
on-site disposal and reliance on
small package plants that are sub-
ject to maintenance/operation prob-
lems. This threat will persist
as long as such systems are used.
In most cases, these methods of
treatment and disposal appear ade-
quate at present; however, increases
in ground water levels and/or pop-
ulation density could render exist-
ing systems unsuitable.
2. High monthly user costs to support
District administration, equipment,
upgrading existing package plants,
and staff. Preliminary cost esti-
mates to upgrade and operate the
five existing package plants range
between $112 to $l,350/month
per facility.
3. Continued septage handling require-
ment .
CENTRAL TREATMENT FACILITY
Beneficial Impacts
1. Enhances safeguards to public
health and to water quality by
eliminating reliance on small
package plants and on-site dis
posal systems.
Adverse Impacts
1. Imposes economic burden on resi-
dents who are presently using
satisfactory on-site disposal
systems but who will be required
to connect and/or contribute
financially to new conveyance
system and treatment plant; pre-
liminary estimate is $12.52/month
user costs.
133
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TABLE 5.11 (continued)
Beneficial Impacts
2.
3.
Adverse Impacts
May facilitate growth and strip
development in Lightner Creek area
with attendant secondary impacts.
Construction-related impacts, e.g.,
noise, dust, erosion hazard, dis-
ruption of traffic flow along pipe-
line alignment
NO ACTION
Beneficial Impacts
1. No additional economic burden to
residents except those associated
with upgrading or replacing failing
systems.
Adverse Impacts
1. Continued threat to public health
and water quality associated with
on-site disposal and reliance on
small package plants that are sub-
ject to maintenance/operations
problems. This threat will persist
as long as such systems are used.
In most cases, these methods of
treatment and disposal appear ad-
equate at present; however, in-
creases in ground water levels
and/or population density could
render existing systems unsuitable.
2. Continued septage handling require-
ment.
134
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TABLE 5.12
POTENTIAL BENEFICIAL IMPACTS AND ISSUES ASSOCIATED WITH
RECOMMENDED ALTERNATIVES FOR GRANDVIEW/LOMA LINDA AREA
Comments
Eliminates continued reliance on
small package plants, many of which
have a history of maintenance problems.
Almost all plants were operating ad-
equately when inspected; however, at
peak loading during tourist season,
many plants experience problems. In-
creases in loading resulting from
greater influx of users, either sea-
sonal use from tourists or increased
population growth could render exist-
ing systems unsuitable. Many do not
have sufficient land area available
for expansion. Most package plants
are non-discharging thereby imposing
minimal threat to surface water qual-
ity. Soils in the area do not allow
appreciable percolation; however, they
are subject to high shrink/swell po-
tential. There is concern that during
dry weather, extensive cracks which
develop in the soils could provide
an avenue by which inadequately treat-
ed wastewater could enter the ground
water system. Due to the reliance
on shallow wells for drinking water
in the Study Area, this is considered
a serious threat to public health.
Improves aesthetics. The existing package plants and 32 of
the 37 individual on-site disposal
systems surveyed rely on surface la-
goons or evapotranspiration systems
for wastewater disposal. Such systems,
if not diligently maintained,are sub-
ject to odor and visual degradation
problems. Many of the existing sys-
tems have a history of such problems.
Elimination of these systems will im-
prove local aesthetic characteristics
in these areas.
Impact/Issues
Enhances safeguards to public
health and to ground water
135
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TABLE 5.12 (continued)
Impact/Issues
Comments
Results in net reduction in
energy usage.
4. Result in greater reliability
of wastewater treatment cap-
ability in Grandview/Loma Linda
area for improved water quality
control.
5. Releases present package
plant and on-site disposal
facilities properties to
alternative land uses.
Discontinued operation of existing
package plants will conserve approxi-
mately 59,100 kwhr of power annually.
The projected annual power consumption
estimates for the Grandview and Loma
Linda treatment facilities are 17,520
kwhr and 13,580 kwhr, respectively,
or 31,100 kwhr, collectively. Im-
plementation of the recommended al-
ternatives results in a net decrease
in electrical energy usage of 28,000
kwhr each year.
Regional facilities will have (1)
better equipment, (2) better and
more uniform operator capabilities,
and (3) back-up power supplies, i.e.,
generators,to assure continued op-
eration in the event of a power
outage.
Land currently used to house waste-
water disposal facilities is, col-
lectively, approximately 1.5 acres
located at 18 separate sites. Imple-
mentation of the recommended alter-
natives will release about 1.4 acres
to other land uses. Approximately
four acres of land will be required
for the two aerated lagoons.
136
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TABLE 5.13
POTENTIAL ADVERSE IMPACTS AND ISSUES ASSOCIATED WITH
RECOMMENDED ALTERNATIVES FOR GRANDVIEW/LOMA LINDA AREA
Impacts/Issues
Imposes economic burden on resi-
dents who are presently using
satisfactory on-site disposal
systems but who will be required
to connect and/or contribute
financially to the regional
collection system and treat-
ment facility.
May facilitate growth in the
Grandview/Loma Linda area with
attendant secondary impacts.
Comments
The issue of who benefits versus who
pays is considered significant. The
recommended alternatives are designed
to correct wastewater management prob-
lems caused by improperly operated systems
many of which require repairs. Most
of the 18 multiple input treatment facili-
ties appeared to be operating adequately
at the time of the survey but 11 either were
experiencing problems, have a history
of problems, or are expected to have
operation difficulties in the future.
Several of the individual on-site fa-
cilities examined in the survey are
in need of repair. The recommended
plans would require all residents in
the proposed service areas instead of just
the individual owner to pay for repairs
to faulty or inadequate systems. Many
of the faulty systems require upgrading
and expansion. In some cases, no land
is available to expand existing sys-
tems. Estimated costs for the rec-
ommended alternatives are:
Grandview
User
Tap
Service
Charge
Fee
Hook-up
Subalt.l $11.49/mo
$700
$500-$1500
Subalt.2 $11.90/mo
$700
$500-$1500
Subalt.3 $10.68/mo
$700
$500-$1500
Loma Linda$11.21/mo
$700
$500-$1500
Land use plan for Grandview and
Pinon Acres is designated at one
dwelling unit per five acres. In
the Loma Linda and Falfa areas a des-
ignation has been made of irrigated
land which is a semi-dormant designa-
tion indicating low priority for
division of lands. Suggested densities
vary between one dwelling unit per
five acres and one per ten acres.
Although it is currently designated
as an area of low density development,
the Grandview/Loma Linda area has been
identified by local planners as a
possible future growth center.
137
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TABLE 5.13 (continued)
Impacts/Issues
Comments
Results in permanent conversion
of approximately four acres
of land for local lagoon sys-
tems.
May degrade aesthetic quality
of area immediately adjacent
to proposed lagoon site, e.g.,
odors, insect nuisance, visual
degradation.
The availability of sewers may relax
constraints on high density develop-
ment. This is especially important
in view of the annual review of land
use ordinances and competing interests
regarding land use management practices.
This includes the two acres each for
the two treatment lagoons plus land
necessary for auxiliary facilities,
e.g., chlorinator and^lift stations.
This impact is considered minimal when
compared to eliminating 18 package
plant sites and approximately 35
individual systems, many of which
currently create odor and visual de-
gradation nuisance. Also, measures
are available to mitigate such occur-
rences.
Construction-related impacts,
e.g., noise, dust, erosion haz-
ard, disruption of traffic flow
along pipeline alignments.
Impacts are temporary and are con-
sidered minimal. Disturbed areas
along pipelines will be restored to
pre-construction conditions after
project completed. Most construction
activities for alignments will be
confined to existing rights-of-way
Grandview
Treatment lagoon:
Sewer lines:
2 acres
3.2 miles
1 highway crossing
Loma Linda
Treatment lagoon:
Sewer lines:
1.5-2 acres
2.0 miles
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The recommended alternative could Increase development potential
there and would almost certainly increase the area's attractiveness to new
development. An increase in development potential would depend on the
effectiveness of the desired growth pattern, which limits residential den-
sities to one living unit per six acres along U.S. Highway 160. If col-
lective wastewater systems were installed, it is possible that the plan
would be changed to allow greater density. The more important impact
of wastewater projects in this area, however, is on the probability of
future development. Soil conditions that are not well suited to septic
systems have been a major factor in inhibiting growth. Removal of this
constraint through installation of a collection system in all or part of
the Study Area would greatly enhance the area's attractiveness and in-
crease the probability that future development would locate there.
Possible mitigation measures for adverse impacts resulting from
implementation of the recommended alternative are summarized in J"able 5.14.
Other Alternatives
Environmental impact analyses were conducted on three other alternative
wastewater management plans for the Grandview/Loma Linda area. These
alternatives include:
1. Collection and interceptor lines to the City of Durango
treatment facility,
2. Formation of a Maintenance District, and
3. No Action.
Impacts associated with these alternatives are presented in Table 5.15.
An additional alternative addressed in the Facilities Plan (i.e. inter-
ceptor line to Animas Air Park) is actually a suboption of alternative 1
above which is to convey wastewater to the Durango facility.
FLORIDA ROAD
Recommended Alternative
The No Action alternative was recommended for the Florida Road area.
The major beneficial impact is no additonal economic burden to residents
except those associated with upgrading or replacing failing systems. A
significant potential adverse impact is the continued threat to public
health and water quality associated with on-site disposal and reliance
139
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on small package plants that are subject to maintenance/operations problems.
This threat will persist as long as such systems are used. In most cases,
these methods of treatment and disposal appear adequate at present;
however, increases in ground water levels and/or population density could
render existing systems unsuitable. The Sanitary Survey revealed that
one package plant is experiencing operation difficulties. The individual
on-site disposal systems examined all appear satisfactory. Another ad-
verse impact associated with the no action alternative is the continued
septage handling requirement. Mitigation for adverse impacts associated
with the No Action alternative can be accomplished by any of the non-
selected alternatives.
Other Alternatives
Environmental impact analyses were conducted on three other alternative
wastewater management plans for the Florida Road area. These alternatives
include:
1. Collection and interceptor lines to Durango treatment plant,
2. Central wastewater treatment facility, and
3. Formation of a Maintenance District.
Impacts associated with these alternatives are summarized in Table 5.16.
An additional alternative addressed in the Facilities Plan (i.e. short
interceptor from the B & C Mobile Home Park to Durango) is actually a
variation of alternative 1 above which is to convey wastewater to the
Durango facility.
WEST ANIMAS
Recommended Alternative
The recommended alternative for the West Animas area is No Action.
The major beneficial impact is no additional economic burden to residents
except that associated with upgrading or replacing failing systems. A
significant potential adverse impact is the continued threat to public
health and water quality associated with on-site disposal and reliance
on small package plants that are subject to maintenance/operations
problems. This threat will persist as long as such systems are used.
In most cases, these methods of treatment and disposal appear adequate
at present; however, increases in ground water levels and/or population
density could render existing systems unsuitable.
140
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TABLE 5.14
POSSIBLE MITIGATION MEASURES FOR POTENTIAL ADVERSE
IMPACTS ASSOCIATED WITH RECOMMENDED ALTERNATIVES
FOR GRANDVIEW/LOMA LINDA AREA
Impact
1. Growth facilitation
2. Aesthetics degradation at new
treatment facilities.
3. Construction-related impacts.
Mitigation
Strict adherence by local officials
to land use plans and zoning ordi-
nances designed to provide orderly,
well-managed growth will prevent
uncontrolled development facilitated
by the proposed alternative.
Adherence to land use plans and options
is a local matter, however, and EPA
has little authority over decisions
made at the descretion of local
authorities.
The treatment plants will be designed
and operated in a manner to prevent
odor and insect nuisance from becoming
a problem. Landscaping the proposed
facilities to blend in with the sur-
rounding environment will mitigate
against visual degradation. The lagoon
systems may enhance local aesthetics
if landscaped and managed for desired
goals such as wetlands, waterfowl
areas, etc.
Standard engineering practice will keep
construction-related impacts to a min-
inum. Excavated areas will be kept to
the minimum required for safe, efficient
operation of equipment. Existing rights-
of-way will be used where possible.
Disturbed areas along alignments will
be restored.
141
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TABLE 5.15
POTENTIAL IMPACTS ASSOCIATED WITH ALTERNATIVES
TO THE RECOMMENDED PLANS FOR THE GRANDVIEW/LOMA LINDA AREA
COLLECTION AND INTERCEPTOR LINES TO THE
TREATMENT PLANT
Beneficial Impacts
1. Enhances safeguards to public
health and to water quality by
eliminating reliance on small
package plants and on-site dis-
posal systems.
2. Releases present package plant
property to alternative land
uses, thereby improving local
aesthetic quality in areas near
these facilities".
3. Result in net reduction in energy
usage.
CITY OF DURANGO
Adverse Impacts
1. Imposes economic burden on resi-
dents who are presently using
satisfactory on-site disposal sys-
tems but who will be required to
connect and/or contribute finan-
cially to new conveyance system
and capacity of Durango treatment
plant; preliminary monthly esti-
mates range between $13.82 (300
users) to $19.78 (179 users) for
Grandview and $11.28 (300 users)
to $17.55 (150 users) for Loma
Linda.
2. May facilitate growth and strip
development with attendant secondary
impacts, as described for recommen-
ded alternative.
3. Construction-related impacts, e.g.,
noise, dust, erosion hazard, dis-
ruption of traffic flow along pipe-
line alignment.
MAINTENANCE DISTRICT
Beneficial Impacts
1. Lessening of threat to public
health and water quality by up-
grading faulty on-site disposal
systems and package plants.
Improved operation of package
plants by providing a licensed
Class C or better operator.
Adverse Impacts
1. Continued threat to public health
and water quality associated with
on-site disposal and reliance on
small package plants that are sub-
ject to maintenance/operation prob-
lems. This threat will persist as
long as such systems are used. In
most cases, these methods of treat-
ment and disposal appear adequate
at present; however, increases in
ground water levels and/or population
density could render existing sys-
tems unsuitable.
-------
TABLE 5.15 (continued)
2. High monthly user costs to support
District administration, equipment,
and staff.
3. Continued septage handling require-
ment.
NO ACTION
Beneficial Impacts
1. No additional economic burden to 1.
residents except those associated
with upgrading or replacing failing
systems.
Adverse Impacts
Continued threat to public health
and water quality associated with
on-site disposal and reliance on
small package plants that are sub-
ject to maintenance/operations prob-
lems. This threat will persist
as long as such systems are used.
In most cases, these methods of
treatment and disposal appear ad-
equate at present; however, increases
in ground water levels and/or popula-
tion density could render existing
systems unsuitable.
Continued septage handling require-
ments.
143
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Existing wastewater treatment in the West Animas area is by indiv-
idual treatment systems and by a non-discharging extended aeration plant
followed by an oxidation ditch. The existing residential units in the
West Animas area are fairly old and it is suspected that several leach
fields need to be upgraded to current standards. The area is constrained
for on-site systems by the Animas River flood plain and high ground water.
The Lazy-U-Rancho operates on extended aeration plant followed by a non-
discharging oxidation ditch. The facility is overloaded and 24-hour
summer blower operation is required simply to prevent odors, with a
resulting low level of treatment. An additional adverse impact assoc-
iated with the No Action alternative is the continued septage handling
requirement. Mitigation for adverse impacts associated with the No
Action alternative can be accomplished by any of the nonselected alter-
natives.
Other Alternatives
Environmental impact analyses were conducted on three other alter-
native wastewater management plans for the West Animas area. These
alternatives include:
1. Collection and interceptor lines to Durango treatment facility,
2. Central wastewater treatment facility, and
3. Formation of a Maintenance District.
Impacts associated with these alternatives are summarized in Table 5.17.
THE RELATIONSHIP BETWEEN LOCAL SHORT-TERM USES OF MAN'S ENVIRONMENT
AND THE MAINTENANCE AND ENHANCEMENT OF LONG-TERM PRODUCTIVITY
The Durango area" has historically been used for residential and
recreational purposes. The Study Area provides habitat for vegetation
and wildlife and serves as valuable watershed. These uses will not be
significantly affected by any of the wastewater management alternatives
considered in the Facilities Plan.
Sewering, either with central treatment in respective Study Areas
or connection to the City of Durango's facilities, would provide the
best long-term protection for water quality and public health; however,
it will impose a significant financial burden on residents. It would also
144
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TABLE 5.16
POTENTIAL IMPACTS ASSOCIATED WITH ALTERNATIVES TO THE
RECOMMENDED PLAN FOR FLORIDA ROAD AREA
COLLECTION AND INTERCEPTOR LINES TO DURANGO
Beneficial Impacts
1. Enhances safeguards to public
health and to water quality by
eliminating reliance on small
package plants and on-site
disposal systems.
Adverse Impacts
1. Imposes economic burden on resi-
dents who are presently using
satisfactory on-site disposal
systems but who will be required
to connect and/or contribute
financially to new conveyance
system and capacity of Durango
treatment plant; preliminary
monthly cost estimates range from
$12.66 to $26.34.
2. May facilitate growth and strip
development with attendant secondary
impacts. Development would prob-
ably be limited because of limi-
tations on water supply and undevel-
oped land.
3. Construction-related impacts, e.g.,
noise, dust, erosion hazard, dis-
ruption of traffic flow along pipe-
line alignment.
CENTRAL WASTEWATER TREATMENT PLANT
Beneficial Impacts
1. Enhances safeguards to public
health and to water quality by
eliminating reliance on small
package plants and on-site
disposal systems.
2. Greater reliability of waste-
water treatment capability
because of better equipment,
better and more uniform op-
erator capability, and back-
up power supply to assure con-
tinued operation in the event
of a power outage.
Adverse Impacts
1. Imposes economic burden on resi-
dents who are presently using
satisfactory on-site disposal sys-
tems but who will be required to
connect and/or contribute finan-
cially to new conveyance system
and capacity of Durango treatment
plant; preliminary monthly cost
estimates range from $15.22 to
$32.80.
2. May facilitate growth and strip
development with attendant secondary
impacts. Development would probably
be limited because of limitation on
water supply and undeveloped land.
3. Permanent conversion of land area
required for lagoon system.
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TABLE 5.16 (continued)
Beneficial Impacts
4.
Adverse Impacts
Construction-related impacts, e.g.,
noise, dust, erosion hazard, dis-
ruption of traffic flow along
pipeline alignment.
MAINTENANCE DISTRICT
Beneficial Impacts
1. Lessening of threat to public 1.
health and water quality by up-
grading faulty on-site disposal
systems and package plants. Im-
proved operation of package plants
by providing a licensed Class C
or better operator.
2.
Adverse Impacts
Continued threat to public health
and water quality associated with
on-site disposal and reliance on
small package plants that are sub-
ject to maintenance/operation prob-
lems. This threat will persist as
long as such systems are used. In
most cases, these methods of treat-
ment and disposal appear adequate
at present; however, increases in
ground water levels and/or population
density could render existing sys-
tems unsuitable.
Monthly user costs higher than those
associated with no action to support
District administration, equipment,
and staff. Preliminary estimate is
from $3.00 to $12.00/month.
Continued septage handling require-
ment.
146
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TABLE 5.17
POTENTIAL IMPACTS ASSOCIATED WITH ALTERNATIVES TO THE
RECOMMENDED PLAN FOR WEST ANIMAS AREA
COLLECTION AND INTERCEPTOR LINES TO DURANGO
Beneficial Impacts
Enhances safeguards to public
health and to water quality by
eliminating reliance on small
package plants and on-site
disposal systems.
Adverse Impacts
Imposes economic burden on resi-
dents who are presently using
satisfactory on-site disposal
systems but who will be required
to connect and/or contribute
financially to new conveyance
system and capacity of Durango
treatment plant; preliminary
monthly cost estimates range
from $15.09 to $30.52.
May facilitate growth and strip
development in Animas Valley with
attendant secondary impacts.
However, most of the area is sub-
ject to physical constraints such
steep slopes and flood plain. Thus,
only a small amount of land is
available. The likelihood of
significant changes in growth
patterns is considered minimal.
3. Construction-related impacts, e.g.
noise, dust, erosion hazard, dis-
ruption of traffic flow along
pipeline alignment.
CENTRAL WASTEWATER TREATMENT PLANT
Beneficial Impacts
1. Enhances safeguards to public
health and to water quality by
eliminating reliance on small
package plants and on-site
disposal systems.
Adverse Impacts
1. Imposes economic burden on resi-
dents who are presently using
satisfactory on-site disposal
systems but who will be required
to connect and/or contribute
financially to new conveyance
system and capacity of Durango
treatment plant; preliminary
monthly cost estimates range
from $10.54 to $22.51.
147
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TABLE 5.17 (continued)
Beneficial Impacts
2. Greater reliability of wastewater
treatment capability because
of better equipment, better and more
uniform operator capability, and
back-up power supply to assure
continued operation in the event
of a power outage.
Adverse Impacts
2. May facilitate growth and strip
development in Animas Valley with
attendant secondary impacts.
However, most of the area is sub-
ject to physical constraints such
as steep slopes and flood plain.
Thus, only a small amount of land
is available. The likelihood of
significant changes in growth
patterns is considered minimal.
3. Permanent conversion of land area
required for lagoon system.
4. Construction-related impacts, e.g.,
noise, dust, erosion hazard, dis-
ruption of traffic flow along
pipeline alignment.
MAINTENANCE DISTRICT
Beneficial Impacts
1. Lessening of threat to public
health and water quality by up-
grading faulty on-site disposal
systems and package plants.
Improved operation of package
plants by providing a licensed
Class C or better operator.
Adverse Impacts
1. Continued threat to public health
and water quality associated with
on-site disposal and reliance on
small package plants that are sub-
ject to maintenance/operation prob-
lems. This threat will persist as
long as such systems are used. In
most cases, these methods of treat-
ment and disposal appear adequate
at present; however, increases in
ground water levels and/or population
density could render existing systems
unsuitable.
2. High monthly user costs to support
District administration, equipment,
and staff. Preliminary estimate is
from $4.00 to $20.00/month.
3. Continued septage handling
requirement.
148
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relax existing constraints on growth and development in certain Study Areas
such as Grandview/Loma Linda, Hermosa, and Junction Creek. A significant
benefit resulting from sewering would be a decrease in current and
projected energy use that would occur by retiring several of the existing
package plants. Individual on-site disposal systems and package plants
would impose less of a financial burden on residents (except those re-
quired to upgrade deficient systems), but the threat to water resources
and public health would continue and perhaps get worse as development
proceeds in the Durango Study Area.
ANY SIGNIFICANT IRREVERSIBLE ENVIRONMENTAL CHANGES WHICH WOULD BE
INVOLVED IN THE PROPOSED ACTIONS SHOULD THEY BE IMPLEMENTED
Materials utilized in the construction of septic tanks, leach fields,
collection and conveyance systems, treatment facilities and disposal
lagoons will not be available for other purposes. The energy resources
(fossil fuel, human and electric power) of the area will be tapped
in order to construct any of the proposed facilities. However, this may
be somewhat offset by the energy savings that would be realized by replacing
existing systems that on an aggregate basis consume more power than would
the proposed facilities. Each of the above commitments involves resources
that are limited in the broadest definition, but are not limited on a
State, regional, and/or local level. The conversion of land to house any
treatment and disposal facilities is considered an irreversible change.
CONSISTENCY WITH AIR QUALITY PLANS
Section 176(c) of the Clean Air Act requires a determination of the
consistency between federally funded projects and the air quality plan for
the area. This wastewater treatment plan must be consistent with the air
quality plan prepared by the San Juan Basin (Region 9) planning agency in
Durango. EPA has concluded that the project is consistent with the air
quality plan and other requirements of the Clean Air Act based on the
following: 1) No State or federal air quality permits are required for the
project because there will be no significant emissions from the treatment
system; 2) Population projections used in the facility plan are consistent
with the air quality plan; and 3) The project complies with all other require-
ments of the air quality plan for the San Juan Basin.
149
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CHAPTER 6
PUBLIC PARTICIPATION
-------
CHAPTER 6
PUBLIC PARTICIPATION
During the course of the 201/EIS study, meetings were held to inform
the public and to solicit public comment. These meetings involved the
public at large, vested interest groups, and governmental entities at the
Federal, state, regional and local level. On 19 March 1979, following
notification in the local newspaper (Durango Herald, 18 March 1979), the
Initial Public Meeting was held to discuss the need for and goals of the
201/EIS study, solicit membership in the Citizens Advisory Group (CAG), and to
explain the roles of the various participants in the study. Membership
in the Citizens Advisory Group was finalized in July 1979. Mr. Joe
Bowden was appointed Public Participation Coordinator to serve as liaison
between the general public, the CAG, and the contractors performing work
on the EIS and Facilities Plan. The CAG met regularly throughout the
duration of the project (generally once each month). During the project,
a decision was made to replace the facilities planning engineer and the
CAG was asked by the La Plata County Commission to review the qualifications
of several engineering firms and recommend the firm best suited to com-
plete the 201 Facilities Plan. This was accomplished and the firm recom-
mended by the CAG was authorized by the Commission to complete the 201
study.
ES staff attended three CAG meetings (19 July, 12 and 19 September
1979) to present information on the progress of the EIS and to answer
questions raised by the CAG. A series of public meetings was held in
May 1980 for each of the communities within the Study Area to discuss
the alternatives being considered for the respective subareas and to
solicit public comment. Information obtained from the area residents
was incorporated into the decision-making process for selection of the
apparent best alternative for each area.
150
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CHAPTER 7
LIST OF PREPARERS
-------
CHAPTER 1
LIST OF PREPARERS
Environmental Protection Agency
John Brink - Ecologist
B.A. in Biology from Washington University, St. Louis. Master of
Forest Science from Yale University. Ten years experience in
environmental management, impact assessment, and ecological studies.
Engineering-Science
Gary L. Potter - Project Manager
B.A. in Zoology from University of California at Santa Barbara, Ph.D.
in Biological Sciences from Dartmouth College. Fifteen years experi-
ence in the field of environmental studies. Projects managed have
included wastewater studies in Arkansas, California, Colorado,
Louisiana, and Texas.
Glynnis Fowler - Environmental Scientist
B.S. in Biology from the College of William and Mary. Four years
experience in air pollution and air quality control, expecially PSD
permitting.
Paul N. Seeley - Environmental Scientist
B.A. in Environmental Biology from the University of Colorado. Seven
years experience in water quality monitoring, water resource planning,
and a variety of wastewater treatment and disposal projects.
Bruce D. Snyder - Environmental Scientist
B.S. in Biology from the University of South Carolina, M.S. in Wildlife
Biology, Clemson University. Eleven years experience in environmental
management, impact assessment, and resource planning.
Janet L. Snyder - Environmental Scientist
B.S. in Zoology from Clemson University. Six years experience in public
health, water quality monitoring, and aquatic and terrestrial ecology.
Allan L. Udin - Sanitary Engineer
B.S. and M.S. in Civil Engineering from Montana State University. Fif-
teen years experience in water and wastewater treatment facility planning,
design, and operation.
151
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Gayle Woodside - Sanitary Engineer
B.S. in Civil Engineering from the University of Texas. Three years
experience in industrial solid waste and wastewater disposal projects.
Gruen, Gruen + Associates
Susanne Lampert - Planning Analyst
A.B. in Urban Studies from the University of California. Nine years
experience in land use economics, public policy analysis, fiscal
analysis and survey research.
Roberta Mundie - Senior Planner
A.B. in Social Sciences from Radcliff College, Master of City Planning
from Harvard University. Fifteen years experience in housing analyses,
economic base studies, and growth management.
Marie A. Mann - Economic Planner
B.S. from Northeastern University, Master of City Planning, Howard
University. Five years experience in urban planning and economic
analyses.
The following persons were contacted during preparation of this document.
Although most were not cited as references they provided useful information
utilized in this study.
Federal
Fischer, Marshall P. - Compliance Assurance Section, U.S. Environmental
Protection Agency, Denver.
Shields, Robert - Fish and Wildlife Service, U.S. Department of the Interior,
Salt Lake City, Utah.
State
Balliger, Robert - Colorado Department of Health, Durango.
Bell, Orlyn - Colorado Division of Water Resources.
Gresh, Art - Colorado Division of Wildlife, Durango.
Haig, Bill - Air Pollution Division, Colorado Department of Health, Denver.
Hess, Lloyd - Director, Colorado Division of Planning, Region 9.
Lile, Daries C. - District Engineer, Colorado Division of Water Resources.
Moore, Ray - Air Pollution Division, Colorado Department of Health, Denver.
152
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Olterman, Jim - Colorado Division of Wildlife, Montrose.
Schrupp, Donald - Colorado Division of Wildlife, Denver.
Weber, Dave - Colorado Division of Wildlife, Denver.
Durango City/LaPlata County
Ebel, Clayton - La Plata County Assessor.
Green, Herbie - Durango Public Works Department.
Jack, Ron - City Manager
Rank, Robert W. - City Manager.
Thompson, Sandy - Councilmember, Durango City Council.
Other Sources
Allen, Cap - Facility Plan engineer.
Bowden, Joe - Chairman, 201 Study Citizens' Advisory Group.
Francis, Ken - Field Representative, Colorado Department of Local Affairs;
Member, 201 Study Citizens' Advisory Group.
Haver, Earl - Basin Reproduction.
Heggen, Mary - Phillips Brandt Reddick Regional Planning
Kirkpatrick, Bruce - Attorney
McCormick, Robert - Member, 201 Study Citizens' Advisory Group.
McDaniels, Lawrence - Attorney, McDaniels and McDaniels.
Murphy, John - LaPlata Electric Association, Durango.
Neal, Nancy - Red Mountain Realty.
Reynold, Dallas - Phillips Brandt Reddick Regional Planning.
Saunders, Jackie - Member, 201 Study Citizens* Advisory Group.
Short, Bud - Member, 201 Study Citizens' Advisory Group.
Vandegrift, Lynn - Vandegrift & Associates
Voelker, John - Member, 201 Study Citizens' Advisory Group.
Welch, Jasper - Durango Chamber of Commerce.
Wheat, Don - Colorado West.
White, Lillian - Member, 201 Study Citizens' Advisory Group.
153
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Wolf, Tim - Phillips Brandt Reddick Regional Planning.
Yates, Russell - Attorney.
154
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REFERENCES
1. Allen, C. 1980. Durango/La Plata County, Colorado 201 Sewer
Facilities Plan.
2. Brogden, R.F., and T.F. Giles. 1976. Availability and
Chemical Characteristics of Ground Water in Central La Plata
County, Colorado. U.S. Department of the Interior, Geological
Survey. Water-Resources Investigations 76-69, Open File Report.
3. Colorado, State of, Department of Local Affairs (in cooperation
with San Juan Regional Commission). 1978. Water Quality
Management Plan for the San Juan Region.
4. Gruen Gruen + Associates. 1980. Socioeconomic Conditions and
Wastewater Facilities Projects.
5. Haig, William. 1980. Colorado Department of Health, Denver,
Colorado. Personal Communication.
6. Henningson, Durham, and Richardson, Inc. 1977. City of
Durango, Colorado, 201 Facility Plan.
7. Murphy, J. 1980. La Plata Electric Association, Durango,
Colorado. Personal Communication.
8. Neal, N. 1980. Red Mountain Realty, Durango, Colorado. Personal
Communication.
9. Wuerthele, M. 1974. Water Quality Survey of the San Juan Basin,
Summer, 1974. Colorado Department of Health, Water Quality
Control Division.
10. Yates, R. 1980. Attorney, Durango, Colorado. Personal Communi-
cation.
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DISTRIBUTION LIST
The agencies and interested groups that have been requested to
comment on the draft EIS are listed below.
Federal Agencies
U.S. Forest Service
Denver, Colorado
U.S. Forest Service
Durango District
Durango, Colorado
Federal Highway Administration
Denver, Colorado
Regional Director
Water and Power Resources Service
Denver, Colorado
Director
Durango Projects Office
Water and Power Resources Service
Durango, Colorado
Regional Director
Heritage Conservation and
Recreation Service
Denver, Colorado
Regional Director
U.S. Fish and Wildlife Service
Denver, Colorado
District Engineer
U.S. Army Corps of Engineers
Sacramento District
Sacramento, California
State Conservationist
U.S. Soil Conservation Service
Denver, Colorado
Regional Director
U.S. Department of Education
Denver, Colorado
Regional Director
U.S. Department of Health
and Human Services
Denver, Colorado
Regional Administrator
U.S. Department of Housing
and Urban Development
Denver, Colorado
State Director
Farmers Home Administration
U.S. Department of Agriculture
Denver, Colorado
District Chief
U.S. Geological Survey
Denver, Colorado
Regional Director
National Park Service
Denver, Colorado
Director
Environmental Project Review
U.S. Dept. of the Interior
Office of the Secretary
Washington, D.C.
Mr. James Biddle
President, National Trust for
Historic Preservation
Washington, D.C.
State Director
Bureau of Land Management
Denver, Colorado
Director
Bureau of Land Management
San Juan Resource Area Office
Durango, Colorado
156
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Federal Agencies (continued)
Ray Kogovsek
U.S. House of Representatives
Washington, D.C.
William Armstrong
U.S. Senate
Washington, D.C.
Field Representative
Office of the Secretary of
the Interior
Denver, Colorado
Gary Hart
U.S. Senate
Washington, D.C.
Regional Health Administrator
U.S. Public Health Service
Denver, Colorado
State Agencies
State Clearinghouse
Division of Planning
Denver, Colorado
Director, Colorado Water
Quality Control Division
State Department of Health.
Denver, Colorado
Colorado Air Pollution
Control Division
State Department of Health
Denver, Colorado
Colorado State Board of
Land Commissioners
Denver, Colorado
Colorado State Land Use
Commission
Denver, Colorado
Environmental Division
Colorado Division of Highways
Denver, Colorado
208 Coordinator
Denver, Colorado
Colorado Department of
Natural Resources
Denver, Colorado
Wildlife Conservation Officer
Durango, Colorado
Colorado Division of Wildlife
Denver, Colorado
Colorado Division of Highways
Denver, Colorado
Robert Denier
Colorado House of Representatives
Denver, Colorado
Dan Noble
Colorado Senate
Denver, Colorado
Colorado State Water Conservation
Board
Denver, Colorado
157
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LaPlata County/City of Durango
LaPlata County Health Dept.
Basin Health Unit
Durango, Colorado
City of Durango
Durango, Colorado
Other
Lightner Creek Sanitation District
Durango, Colorado
Phillips, Brandt, Reddick, Inc.
Durango, Colorado
Sierra Club
Denver, Colorado
Denver Audubon Society
Denver, Colorado
Rocky Mountain Center on
Environment
Denver, Colorado
Thorne Ecological Institute
Boulder, Colorado
Environmental Impact Assessment
Project
Washington, D.C.
Colorado Municipal League
Wheatridge, Colorado
Colorado Wildlife Federation
Boulder, Colorado
Environmental Action of Colorado
Denver, Colorado
Environmental Defense Fund
Denver, Colorado
Durango Herald
Durango, Colorado
158
LaPlata County Commissioners
Durango, Colorado
San Juan Regional Commission
Durango, Colorado
West Animas Sanitation District
Durango, Colorado
201 Advisory Group
Durango, Colorado
National Audubon Society
Boulder, Colorado
National Wildlife Federation -
Washington, D.C.
Colorado Ski Country USA
Denver, Colorado
Today
Durango, Colorado
Trout Unlimited
Denver, Colorado
Durango Chamber of Commerce
Durango, Colorado
League of Women Voters of Colorado
Denver, Colorado
N. K. Linton, Citizens' Advisory
Group
Durango, Colorado
Joe Bowden, Citizens' Advisory Group
Durango, Colorado
Robert McCormick
Citizens' Advisory Group
Durango, Colorado
-------
Other (continued)
Jacklyn Sanders
Citizens' Advisory Group
Durango, Colorado
Lillian White
Citizens' Advisory Group
Durango, Colorado
Lloyd Hess
Citizens' Advisory Group
Durango, Colorado
Buddy Shurac
Citizens' Advisory Group
Durango, Colorado
Del Cook
Citizens' Advisory Group
Durango, Colorado
John Voelker
Citizens' Advisory Group
Durango, Colorado
Bob Ballinger
Citizens' Advisory Group
Durango, Colorado
Ken Francis
Citizens' Advisory Group
Durango, Colorado
E. L. Hutchinson
Citizens' Advisory Group
Durango, Colorado
159
-------
GLOSSARY
OF
WASTEWATER TERMS
Source:
American Society for Testing and Materials
Special Publication No. 442
-------
GLOSSARY
Technical terms not in ordinary use, and
words used in the Manual in a special sense,
are defined below Definitions given in Stand-
ard D 11291 are not repeated here.
Absorption—Assimilation of molecules of other
substances into the physical structure of a
liquid or solid without chemical reaction.
Absorption, radiation—1. The process whereby
the number of particles or photons emerging
from a body is reduced relative to the number
entering, as a result of interactions of the par-
ticles with the body.
2. The process whereby part or all of the
energy of a particle or of electromagnetic radia-
tion is lost while traversing a body of matter.
Absorption tower—A vertical structure for carry-
ing out an absorption process.
Acid—A compound which dissociates in water
solution to furnish hydrogen ions.
Acid anhydride—An oxide which will form an
acid when united with water.
Acid mine drainage—Acidic drainage from bitu-
minous coal mines, containing a high concen-
tration of acidic sulfates, especially ferrous
sulfate.
Acid radical—The anion in equilibrium with the
hydrogen ion of an acid.
Acidify—1o make acidic by the addition of
acid or add salt.
Acidimeiry—The art of determining the acidity
of aqueous solutions.
Activation—The process of inducing radioactiv-
ity in a material through nuclear bombard-
ment, especially by neutrons.
Activation analysis—A method of chemical anal-
ysis, especially for trace quantities, based on
the detection of characteristic radionuclides
following nuclear bombardment
Adsorption—Physical adhesion of molecules to
the surfaces of solids without chemical re-
action.
Aerobic—Living only in the presence of free
oxygen.
11988 Book of ASTM Standardj, Part 23.
Agglomerate—To gather together into a larger
mass or cluster; to coalesce.
Albuminoid—Any of a number of substances
resembling the true proteins such as collagen
and keratin. A protein in its broad sense
Algae—Simple forms of aquatic plant life which
multiply only by division, but contain chloro-
phyll and use sunlight (or photosynthesis.
Aliquot—A measured fraction of the known total
volume of a solution.
Amorphous—Structure without crystalline com-
ponents; having no determinate shape.
AmperomdricaUy—Determined by measurement
of electric current flowing or generated, rather
than by voltage measurement
Anaerobic—Living in the absence of free oxygen
Analysis, chemical—Determination of the chem-
ical elements or constituents of a compound or
mixture. Also a statement of the results of
such a determination.
Angstrom unit—A measurement of length usu-
ally applied to light or other radiation wave-
lengths—0 0001 ji, cm/10'.
Anion—A negatively charged ion resulting from
dissociadon of molecules in aqueous solution.
Anode—The positive pole in an electrolytic cell
which attracts negatively charged particles
or ions (anions).
Anthrax—A malignant infectious disease of cat-
tle, sheep, and other animals, and of man,
caused by Bacillus anihracis.
Arc, ntible—An electrical discharge in which
radiation of wavelengths discernible by the
normal human eye is produced.
Arthropods—Animals with articulate body and
limbs.
Ascante—A proprietary absorbent for carbon
dioxide consisting of asbestos fibers impreg-
nated with dehydrated sodium hydroxide
Aspirator—A type of suction pump operated
from a laboratory water tap.
Autotrophs—Microorganisms which utilize in-
organic materials for energy and obtain car-
bon from the carbon dioxide of the atmosphere.
Background, instrument—Undesired counts or
responses due to cosmic rays, local contami-
-------
nating radio-activity, electronic noise, and the
like. Background is sometimes used to refer to
the radiation causing the undesired response.
Backwash—Reversed flow of liquid for cleaning
or the discharge from such an operation.
Bacteria—One-celled microscopic organisms.
Bacteria, iron—Bactena which assimilate iron
and excrete its compounds in their life proc-
esses, thereby contributing to corrosion.
Bacteria, non-pathogenic—Bacteria which do not
induce disease in man or the higher animals.
Bactena, pathogenic—Microorganisms that pro-
duce disease.
Bacteria, sulfate-reducing—Bacteria which as-
similate oxygen from sulfate compounds,
thereby reducing them to sulfides.
Bacteriophage—A viral agent that dissolves spe-
cific bacterial cells.
Balance, water—A material account of the weight
of water entering and leaving an industrial
installation or process.
Basic—Alkaline.
Beam trap—A device on an X-ray-diSraction
camera for absorbing the undiffracted pri-
mary X-ray beam after it has passed through
the sample.
Biota, stream—The collective animal and plant
life of a stream.
Birefringence—The difference between the max-
imum and minimum index of refraction of a
crystal.
Blanket—A layer of material outside the core of
a reactor in which fissionable materials are pro-
duced through neutron activation.
BUrwdown—Draining off a portion of the liquid
in a vessel, usually to reduce the concentration
of the remaining liquid.
BOD—Biochemical oxygen demand of a water—
the oxygen required for oxidation of the soluble
organic matter by bacterial action in the pres-
ence of oxygen.
Bovine tuberculosis—An infectious disease affect-
ing any of various tissues of the body due to
the tubercle bacillus and characterized by the
production of tubercles.
Brine—Concentrated solution, especially of
chloride salts.
Bromination—Chemical treatment with bro-
mine.
Brucellosis—Infection with bacteria of the
Brucella group, frequently causing abortions
in animaU and undulant fever in man.
Buffer—A substance which tends to resist
changes in pH of a solution.
Buffered water—Water containing dissolved or
suspended material which resists changes in
the pH of the water.
Calibration—The process of standardizing.
Carbonate hardness—That hardness In a water
caused by bicarbonates and carbonates of cal-
cium and magnesium.
Carryover—Entrainnient of liquid or solid par-
ticles from the boiling liquid in the evolved
vapor; also the particles so entrained.
Cathode—The negative pole of an electrolytic
cell which attracts positively charged particles
or ions (cations); the negative electrode of a
vacuum tube.
Cathodic protection—Reduction or prevention of
corrosion of a metal surface by making it
cathodic by use of sacrificial anodes or im-
pressed currents.
Cation—A positively charged ion resulting from
dissociation of molecules in solution.
Cavitation—The formation of cavities in a liquid
by rapid movement over confining or impelling
surfaces and the subsequent collapse of these
cavities; the destruction of metal surfaces as
a result of cavitation in the liquid.
Centrifuge—A device for separating the lighter
and heavier portions of a fluid by centrifugal
force.
Chamber, ionization—An instrument whose
response to radiation is due only to collection
of the ions formed by the interaction of the
radiation with the chamber materials.
Chelating agents—Chemical compounds which
ha\e the property of withdrawing ions into
soluble complexes.
Chiorinator—A machine for feeding either liquid
or gaseous chlorine to a stream of water.
Coagulation—The coalescence of fine particles to
form larger particles.
Collimator lube—A device for defining the path
of rays, such as light or X-rays
Colloidal—Matter of very fine particle size, usu-
ally in the range of 10"' to 10^ cm in diameter.
Colorimeter—A device for measuring or compar-
ing colors or colored solutions.
Colorimeter, photoelectric - cell — A colorimeter
which measures the light transmitted through
a solution by the response of a photoelectric
celL
Colorimetric determination—An analytical pro-
cedure based oq measurement, or comparison
with standards, of color naturally present in
samples or developed therein by addition of
reagents.
Combinations, molecular—Possible mutual ar-
rangements of the known proportions of
anions and cations present in a mixture
Combinations, probable—The most likely man-
ner, in the judgment of the analyst, in which
the ions of a solution or the constituents of a
deposit are combined into compounds in the
original sample.
Combining weight—The relative or equivalent
weight of an element or compound which
-------
Fauna—Animals, or animal life
Ferrobacillus ferrooxidans—An autotrophic bac-
— tenum which oxidizes ferrous iron under acid
conditions.
Filamentous—Having the shape of a fine thread-
like bod/ or structure.
Film badge—An appropriately packaged photo-
graphic film for detecting radiation exposure
of personnel
Filter plant—The portion of a plant containing
the equipment employed to strain water for the
removal of suspended solids.
Filtrate—The liquid which has passed through a
filter.
Filtration—The process of separating solids from
a liquid by means of a porous substance through
which only the liquid passes
Fission—The splitting of a nucleus into two
more or less equal fragments, usually as a
result of the capture of a bombarding particle,
especially a neutron. In addition to the two
fragments, neutrons and gamma rays are usu-
ally emitted during fission.
Fission products—The nuclides produced by the
fission of a heavy element nuclide such as
uranium-233, uranium-235, or plutonium-239
Flame photometer—Apparatus for giving a re-
producible amount of emitted light for a given
concentration of element in the test solution,
and for determining the intensity of such
emission as a function of concentration of the
element without excessive interference from
other emitted light.
Flashing—The conversion of a portion of a hot
liquid under pressure to its vapor by release
of the pressure.
Floe—A felted mass formed in a liquid medium
by the aggregation of a number of fine sus-
pended particles.
Flora—Plants, or plant life.
Flow cells—A sensing element or combination of
elements, such as electrodes, immersed in a
Sowing liquid or gas for the purpose of meas-
uring continuously some property of the fluid,
such as electrical conductivity.-'
Flaw diagram—The diagrammatic representation
of a works process, showing the sequence and
interdependence of the successive stages.
Flumed—The transportation of solids by suspen-
sion or flotation in flowing water.
Fluorescence—The absorption of radiation at one
wavelength or range of wavelengths and its
re-emission as radiation of longer, visible
wavelengths.
Flux—The number of particles or photons pass-
ing through a surface per unit time; for elec-
tromagnetic radiation, the energy passing
through a surface per unit time.
Fluxing—Addition ol a low-melting compound
to a substance to decrease fusion temperature ol
the mixture. '
Geiger-Mueller tube—A gas-filled chamber with
electrodes operated at a voltage such that a
discharge triggered by a primary ionization
event will increase until stopped by reduction of
the electric field The size of the response if
independent of the unit amount of primary
ionization.
Geometry—The average solid angle at the source
subtended by the aperture or sensitive volume
of a detector, div ided by 4x Geometry is fre-
quently (but loosely) used to denote over-all
counting efficiency
Glass electrode—An electrode consisting of a thin
glass membrane separating solutions of known
and unknown pH value, the potential differ-
ence between the two sides being measured
for determining the pH of the unknown.
Grain per gallon—A measure of solution concen-
tration—17.1 ppm.
Grating—A band of equidistant, parallel, straight
lines ruled on a suitable surface for systemat-
ically dispersing polychromatic light into its
separate wavelength components.
Gravimetric—Measured by weight.
Ground water—Water derived from wells or
springs, not surface water from lakes or
streams.
Gases, half-bound—Gases, such as carbon dioxide,
which are evolved by decomposition of un-
stable ions upon heating.
Balf-life—The average time required to uduce
the amount of a particular radionuclide to
half its original value through radioactive
disintegration.
Beat exchanger—A mechanical device by which
heat is transferred from a flowing fluid within
tubes to another outside the tubes.
Beat transfer—The process of removing heat
from a hot body or fluid to another, usually
through an intervening wall.
Sealer, feed-water—A heat exchanger for raising
the temperature of feedwater.
Beterotrophs—Microorganisms which must ob-
tain carbon from organic compounds.
Bomogeneous—Of uniform composition through-
out
Bot-wdl, condenser—Reservoir at the bottom of
a condenser shell for collecting condensed
water.
Bumidity—The concentration of water vapor in
an atmosphere
Bydrazme—An ammonium compound, NjH<,
which is used as an orygen scavenger in boiler
water
Hydrometer—A buoyant instrument with gradu-
ated stem for measuring the specific gravity
of liquids
-------
Hydroponics—Growth of plants in nutrient solu-
tion rather than In earth.
Hygroscopic—Tending to absorb moisture from
the atmosphere.
Hypochlorite solution—Bleaching or sterilizing
solution containing (OCl)~ ion.
Incubation—Maintenance of viable organisms
in nutrient solution at constant temperature
for controlled growth or reproduction.
Index oj refraction—Ratio of the velocity of light
in the substance in question to the velocity of
light in a vacuum.
Indicator—Substance which gives a visible
change, usually of color, at a desired point in
¦ a chemical reaction.
Inoculate—To introduce a small amount of sub-
stance into a solution for observation of its
effect such as growth or crystal formation.
Intensity, line-spectra—Intensity of the char-
acteristic lines in the spectrum of an exated
element.
Interfering substances—Materials which restrict
or prevent a desired reaction, or contaminate
the product. _
lodimetry—Measurement by consumption or re-
action of iodine, usually in solution.
Ion—An atom or radical in solution carrying an
integral electrical charge either positive (ca-
tion) or negative (anion).
Ion exchange—A process by which certain ions
of given charge may be absorbed from solu-
tion and replaced in the solution by other
ions of similar charge from the absorbent.
Isotropic—Having the same optical properties
in all directions.
Kjeldakl determination—The chemical determin-
ation of nitrogen by which organic material is
decomposed and its nitrogen converted to
ammonia.
Latent energy—The energy (heat) required for a
change of state at constant temperature, as the
thawing of ice into water or the evaporation
of water into steam.
Lattice—The uniform, three-dimensional ar-
rangement of atoms or ion groups in a crystal
Leach—To dissolve certain constituents from a
larger mass by a slow washing operation.
lignin—The major non-cellulose constituent of
wood.
Macro—Large, as compared with micro (small).
Macro sample—One large enough to be weighed
accurately on an analytical balance.
Macrochcmical—Oa a normal scale of weights
and volumes, as opposed to microchemical
Membrane, porous—A barrier, usually thin,
which permits the passage only of particles
up to a certain size or of special nature.
Metabolism—The process by which food is used
and wastes are formed in living matter.
Methemoglobinemia—Condition resulting from
intake of excessive quantities of nitrate (blue
babies)
Microbiological—Pertaining to very small living
matter and Us processes.
Microbiota—Microscopic plants and animals.
Microchemical—Chemical reactions on a very
small scale.
Microorganism—Minute living matter.
Microscopic—Minute, very small; pertaining to
a microscope.
Microscopy, chemical—Identification by micro-
scopic observation of both chemical reactions
and optical properties.
Moderator—Material used in a nuclear reactor to
slow neutrons from the high energies at which
they are released. Moderators are usually
materials of high scattering cross-section, low
atomic weight, and low absorption cross-sec-
tion.
Molds—Filamentous fungi composed of many
cells.
Monitoring, radioactive—Periodic or continuous
determination of the amount of ionizing radia-
tion or radioactive contamination present in
any area, as a safety measure for health pro-
tection.
Mother liquor—A solution substantially freed
from undissolved material by filtration, decan-
tation, or centrifuging.
MPC—Maximum permissible concentration.
See Concentration, maximum permissible.
Nepkelometry—Measurement of the light scat-
tered by turbid liquids.
Nessler tubes—Matched cylinders with strain-
free, dear-glass bottoms for comparing color
density or opacity.
Nesslerization—A process for determining am-
monia by its reaction with a mercury complex
in alkaline solution.
Neutralization—Reaction of aad or alkali with
the opposite reagent until the hydrogen ions
are approximately equal to the hydroxyl ions
in the solution.
Neutron actuation analysis—Activation analysis
using neutrons as the bombarding particle.
Nitrobacter—A genus of bacteria that oxidize
nitrite to nitrate.
Nitrogen, organic—Nitrogen combined in organic
molecules such as proteins, amines, and amino
adds.
Nitrosomonas—A genus of bacteria that oxidize
ammonia to nitrite.
Noncarbonate hardness—Hardness in water
caused by chlorides, sulfates, and nitrates of
calcium and magnesium.
Non-condensable—Gaseous matter not liquefied
or dissolved under the existing conditions.
Non-referee—A method of test featuring speed
-------
and practical usefulness rather than high ac-
curacy, which is used for process control and
general information rather than in settlement
of disputed test results.
Nuclide—A species of atoms with a given nuclear
constitution, described by the number of pro-
tons Z, the total number of nucleons (protons
plus neutrons) A, and (if necessary) the energy
state. Usually only atoms capable of existing
for a time of the order of 10~10 seconds or
longer are considered to be nuclides.
Nutrient—Food.
Objective—The lens, or set of lenses, opposite the
eyepiece in a microscope, which forms an
image of the specimen.
Occlusion—An absorption process in which one
matenal adheres strongly to another, usually
a solid.
Opacity—The ratio of transmitted to incident
light.
Orientation—The relative position of particles
with respect to one another or to a reference
point.
Orientation, crystal—The geometric relationship
between the optical axes and an external refer-
ence.
Orifice—\ restricted opening of known dimen-
sions, usually for limitation or measurement
of fluid flow
Oxidation—Reaction of a substance with oxygen,
loss of electrons by one element to another
element.
Oxide—A chemical compound of a metal, or
group of elements which act in common as a
metal, with oxygen.
Oxide, basic—An oxide which forms hydroxide
on reaction with water.
Oxygen demand—Oxygen required for oxidation
of inorganic matter, or for stabilization of de-
composable organic matter by aerobic bac-
terial action.
Pathogenic—Causing disease.
Pathofetis—Pathogenic or disease-producing
organisms. ^
Photometer—An instrument which measures the
intensity of light or degree of light absorption.
Photon—The smallest unit of electromagnetic
radiation. The term photon is most commonly
used in reference to the particulate aspect of
electromagnetic radiation. A photon of radi-
ation frequency » has an energy hr and a mo-
mentum hr/c, where c is the velocity of light
in vacuo.
Photosynthesis—Formation of chemical com-
pounds in chlorophyll-containing tissues of
plants exposed to light
Physical tests—Determinations based on obser-
vation or measurement of physical properties
Pollution—The result of discharging normally
foreign material into ground or surface water
Polyphosphate—Molecularly dehydrated ortho-
phosphate.
Precipitate—An insoluble compound formed by
chemical reaction between two or more nor-
mally soluble compounds in solution.
Priming—A carry-over of water with a sudden
generation of steam, like the bumping which
sometimes occurs a hen water is boiled m an
open vessel.
Process, liol-floio—Mdition of chemicals to hot
water (200-212 F) passing slowly through a
reaction tank
Proliferation—The grow, th or production by mul-
tiplication of parts as in budding or cell di-
vision.
Protozoa—Microscopic, one-celled animals
Purity, steam—An inverse measure of the non-
water (salts, solids, oil) constituents of steam
Quality, steam—An inverse measure of the en-
trained, unevaporated moisture m steam.
Qualitative—Pertaining to the nature of com-
ponent parts rather than to the amount of
such components present
Quench—To cool a material suddenly; halt ab-
ruptly a process or reaction.
Radiation—The emission and propagation of en-
ergy through space or through a material me-
dium; also the energy so propagated.
Radioactivity—Spontaneous nuclear disintegra-
tion with emission of particulate or electro-
magnetic radiations.
Radionuclide—A radioactive nuclide.
Radiotracer—A tracer which is detected by
means of its radioactivity.
RatnotU—See Fallout.
Rcactant—A substance which undergoes chemi-
cal change in contact with another substance.
Reactor—An assembly capable of sustaining a
fission chain reaction.
Reconstitution—The restoration of the original
characteristics of a specific water.
Recycled—Having flowed more than once
through the same series of processes, pipes, or
vessels.
Referee method—A method of test, usually of the
highest accuracy available, which is used by
mutual consent of contracting parties for es-
tablishing an acceptable value or quality in
settlement of disputed test results.
Refractory—Heat-resistant, fusible with diffi-
culty.
Regeneration—Restoration of water-treating
power to an ion exchanger.
Rehydration—Recombination of water with a
molecule of a chemical compound
Reprecipxialion—Dissolving a precipitate and
then re-forming it by repetition of the pre-
-------
vious procedure. (Used as a purification step
in analysis)
Residue—That which remains after a part has
been separated or otherwise treated
Resolving power—Capacity of an optical system
to distinguish adjacent images.
Riparian—Of, pertaining to, or situated, or
dwelling on the bank of a river or other body
of water.
Rotifers—Minute, many-celled aquatic animals.
Runojf—Water flowing to a stream as a result of
rainfall or melting snow.
Saprophytic organism—Any organism living on
dead or decaying matter.
Scintillation—The production of light photons
by the interaction of radiation with a suitable
material.
Sedimentation—Gravitational settling of solid
particles in a liquid system.
Self-absorption—The absorption of radiation par-
ticles or photons in the source itself.
Sequester—To form a stable, water-soluble com-
plex.
Settling basin—Reservoir receiving water after
chemical mixing to permit settling of the fioc
Shielding—Material used to prevent or reduce
the passage of radiation particles or photons.
Slimes—Substances of viscous organic nature,
frequently derived from microbiological
growth.
Sludge blanket—A horizontal layer of solids hy-
drodynamically suspended within an enclosed
body of water.
Softener, base-exchange—Water softener using an
lon-eichange material.
Softener, lime-soda—Water softener using cal-
cium hydrate and sodium carbonate as the
reacting chemicals.
Solubility—Degree to which a substance will
dissolve in a particular solvent.
Solutes—Substances which are dissolved in a
liquid.
Solid solution—Mixture of two or more isomor-
phous substances in a single crystal form.
Species—A classification group having only mi-
nor details of difference among themselves.
Specific gravity—Ratio of the weight of any vol-
ume of a substance to the weight of an equal
volume of water at 4 C.
Spectrograph—Instrument used for photograph-
ing a spectrum.
Spectrophotometry—Quantitative measurement
with a photometer of the quantity of light of
any particular wavelength absorbed by a
colored solution, or emitted by a sample sub-
jected to some form of excitation such as a
flame, arc, or spark.
Spectroscope—Instrument used to view spectra
emitted by bodies or substances. ~
Spectroscopy—Application of spectroscope to in-
\ estimation of chemical composition
Spore—A minute resistant body within bac-
teria, considered as a resting stage of bacteria.
Spray ponds—Ponds or basins in which cooling
water is pumped and sprayed through nozzles,
thereby reducing the water temperature by
t\aporation.
Stage, mechanical—The device used to manipu-
late a specimen under the lens of a microscope
for examination.
Standardization—The manipulations necessary
to bring a preparation to an established or
known quality, for example, the preparation
and adjustment of a standard solution in volu-
metric analysis.
Staphylococci—A genus of sphere-shaped, pus-
forming bacteria
Statistical uncertainty—That portion of the un-
certainty of a radioactivity determination due
to the random variation in the disintegration
process
Stoichiometric—The fixed weight ratios in which
elements combine into chemical compounds
Streptococci—A genus of sphere-shaped bacteria
forming chains of cells; produce pus.
Strongly basic acid absorber—An ion-exchange
resin in which the hydroxy! ion exhibits a very
low exchange potential.
Sulfuritic material—Compounds of sulfur and
iron represented by the formula FeSi.
Superheater—A heat exchanger in which steam
is heated above the equilibrium temperature
corresponding to the operating pressure.
Supernatant—The liquid standing above a sedi-
ment or precipitate.
Surrey meter—A portable instrument for detect-
ing and measuring radiation under varied
physical conditions.
Thermal shock—A stress-strain condition set up
by a sudden change in temperature.
Titration—The determination of a constituent
in a solution by the measured addition of a re-
active, standard solution of known strength
until the reaction is completed.
Titer—The concentration of a dissolved sub-
stance as determined by titration.
Tracer—A foreign substance mixed with or at-
tached to a given substance to enable the dis-
tribution or location of the latter to be deter-
mined subsequently.
Tritium—A radioactive hydrogen isotope of
atomic weight 3.
Tube bank—A large number of metal tubes set
parallel and close together, as in a boiler.
Tube failure—Leakage or bursting of tubes re-
sulting from corrosion, overheating, etc.
Tuberculation—A type of corrosion in which the
corrosion products form blisters or nodules.
-------
Turbidimeter—Instrument for determining the
quantity of matter, in the form of fine sus-
pended particles, in a liquid.
Turbidity—The reduction of transparency of a
liquid due to the scattering of light by sus-
pended particles.
Undulant Jeter—An irregular, relapsing fever,
with spelling of joints, spleen, and rheumatic
pains caused by Brucella organisms
Vacuum deaeration—Equipment operating under
vacuum to remove dissolved gases from water
in the cold.
Vacuum-return system—A system whereby a
vacuum is applied to the return pipes to facili-
tate the flow of condensate back to the boiler
Viable—Living and potentially reproductive
Virus—Submicroscopic infectious agent
Volatile—Capable of being readily evaporated
at relatively low temperature.
Volatilize—To convert into a gas or vapor
Volumetric—Pertaining to measurement by vol-
ume, as opposed to gravimetric.
Waste—Any material which is of no further
utility to the particular process involved.
Water of crystallization—Water which is an in-
tegral constituent of crystals or hydrated salts.
Water hammer—A sharp, hammer-like blow
caused by the sudden stoppage of water flow
in a long pressure conduit due to the rapid
closing of valves It may also be caused by the
sudden collapse of steam bubbles upon enter-
ing cold water.
Weakly basic acid absorber—An ion-exchange
resin in which the hydroxyl ion exhibits an
exceedingly high exchange potential.
Weir boxes—Dams over which, or through a
notch in which, the liquid earned by a hori-
zontal open channel is constrained to flow for
measurement.
Westphal—.\ type of weighing balance for de-
termining the specific gravity uf liquids and
solids.
X-ray Aijjrachon—A method of identifying crys-
talline substances by means of the scattering
of X-rays by the constituent atoms to form
characteristic patterns
Yeasts—Broad group of fungal microorganisms
causing fermentation.
Zeolite—A group of hydrated aluminum complex
silicates, either natural or synthetic, with cat-
ion-exchange properties
Zeolite, regenerating—A zeolite capable of being
regenerated or converted to its original form
by brine treatment
Zeolite softeners—Equipment containing zeolite
for softening water.
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TECHNICAL REPORT DATA
1Please read Instructions on the reverse before completing)
1 REPORT NO
EPA- 908/5-81-001^
2
3 RECIPIENT'S ACCESSION NO.
4. TITLE ANO SUBTITLE
Draft Environmental Impact Statement
S REPORT DATE
February 1981
Wastewater Management Plan for the Durango Area
La Plata County, Colorado
6. PERFORMING ORGANIZATION CODE
7 AUTHOR(S)
John M. Brink, EPA
Gary L. Potter, Engineering Science
8. PERFORMING ORGANIZATION REPORT NO
9 PERFORMING ORGANIZATION NAME ANO ADDRESS
ENGINEERING SCIENCE, Inc.
10 PROGRAM ELEMENT NO
2785 North Speer Blvd., Suite 140
Denver, CO 80211
11. CONTRACT/GRANT NO
12 SPONSORING AGENCY NAME ANO ADDRESS
U.S. Environmental Protection Agency, Recion VIII
13 TYPE OF REPORT AND PERIOD COVERED
Draft
1860 Lincoln Street
Denver, CO 80295
14 SPONSORING AGENCY CODE
8W-EE
15 SUPPLEMENTARY NOTES
Complements Environmental Assessment dated September 10,
1979
16 ABSTRACT
Environmental effects of wastewater management were considered for six areas outside
of the Durango City limits in La Plata County, Colorado. Three basic wastewater
management alternatives were proposed for each Study Area: (1) No Action (2) Forma-
tion of a Maintenance District, and (3) Sewers, either with a local treatment facil-
ity or with connections to the City of Durango's system. Environmental impacts of
the Mo Action and Maintenance District alternatives include possible degradation of
water quality, potential public health threats, and septaae and sludqe disposal.
While it would reduce these impacts and save electrical energy, the sewer alternative
might lead to increased growth rates, strip development alonq the sewer lines, and
increased population density. The Maintenance District and sEwer alternatives would
also impose substantial financial impacts on residents, particularly those with
properly operating existing systems. Connection with the City of Duranqo's system
could lead to annexation under implied consent rules. No Action was recommended for
the West Animas and Florida Road Study Areas. Interceptors to the City of Durango
system were recommended for the remainder of the Junction Creek and Liqhtner Creek
areas. Local sewage treatment plants with sewers were recommended for the Hermosa and
Grandview/Loma Linda areas.
17
KEY WORDS AND DOCUMENT ANALYSIS
a DESCRIPTORS
b 1DENTI FIE RS/OPEN ENDED TERMS
c COS ATI Field/Group
Sewer Interceptor
Individual Disposal Systems
Privately Owned Small Wastewater Treatment
Systems
Local Land Use Plans
Environmental Impact Statement
City of Duranqo
La Plata County, Colorac
O
18 DISTRIBUTION STATEMENT
Release Unlimited
19 SECURITY CLASS (This Report)
21 NO OF PAGES
20 SECURITY CLASS (This page)
22 PRICE
EPA Form 2220-1 (Rev. 4-77) previous edition is obsolete
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