DRAFT
DENVER REGIONAL
ENVIRONMENTAL IMPACT
STATEMENT FOR
WASTEWATER FACILITIES
AND THE CLEAN WATER
PROGRAM
U.S. ENVIRONMENTAL
PROTECTION AGENCV
REGION VIII, DENVER
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DRAFT
DENVER REGIONAL
ENVIRONMENTAL IMPACT STATEMENT
for
WASTEWATER FACILITIES
and the
CLEAN WATER PLAN
Prepared by
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION VIII, DENVER
June 1
Approved By:
areen
'Regional Administrator
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Denver Region
Section 201 Facility Plans
Section 208 Area Management Plan
(.X) Draft ( ) Final Environmental Statement
1. Name of Action: (X) Administrative ( ) Legislative
2. Description of Action; Various local agencies have proposed or are
developing proposals to construct, improve and/or expand municipal
wastewater collection and treatment systems for the following eight
planning areas:
1. South Adams County
2. Englewood and Littleton
3. South Lakewood
4. Cherry Creek and Goldsmith Gulch
5. Lower South Platte
6. Clear Creek and Sand Creek
7. Westminster and Broomfield
8. Metropolitan Denver Sewage Disposal District No. 1
Planning for these municipal wastewater collection and treatment
system modifications has or will be carried out with local agency and
EPA funds under Section 201 of Public Law 92-500. These planning efforts
examine a number of alternative means of achieving effluent standards
derived from water quality goals. The Denver Regional Council of
Governments (DRCOG), the designated 208 planning agency, has released the
draft Clean Water Plan (208 plan), for public review. As the draft Clean
Water Plan addresses the same water quality issues, and must be also
approved by EPA, this action is included with the actions required for
the eight facility (201) plans.
The Environmental Protection Agency has received or is anticipating
requests to fund 75 percent of the construction costs for wastewater
collection and treatment facilities for eight service areas in the
Denver Region and to approve the Clean Water Plan. Each of these
funding requests for proposed projects and the approval of the Clean
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f AOW\ action by EPA which may
Water Plan represents a proposed major federal acLxui ' Under
have a significant effect on the quality of. ^^f^^A must
the provisions of the National Environmental Policy Act (NEPA^
prepare an Environmental Impact Statement, and consider tne «
consequences thus disclosed before making a decision as to wnetner c
provide the requested funds and approvals.
The purpose of preparing one EIS for eight project proposals and the
Clean Water plan, instead of a separate EIS for each project proposal,
is to provide a framework for examining cumulative regionwide etiects.
Experience has shown that regionwide environmental effects of wastewater
collection and treatment facilities for urban areas are linked to the
future growth those facilities are designed to serve. The EPA is
concerned that actions it may take to improve regional water quality
goals may jeopardize the attainment of other environmental goals.
3. Environmental Impacts:
(1) The region will continue to grow in both population and
urbanized areas at the expense of existing and potential agricultural
areas. The existing, complex framework of government agencies will
hinder the solutions of region-wide problems.
(2) Urban sprawl is expected to continue with the migration of
the affluent and advantaged to the suburbs. Out-migrants from the
urban core will be replaced in large measure by the poor, the old,
minorities and the disadvantaged. Economic growth in the suburbs will
be more rapid than in the urban core. Physical and economic decay of
the urban core is expected.
(3) Damage to park and recreational facilities resulting from
overuse or vandalism will continue and intensify as park acreage per
capita ratio decrease.
(4) Public health and soil damage impacts will occur as a
consequence of agricultural irrigation with wastewater treatment plant
effluent unless State of Colorado and local public health and agri-
cultural officials establish effective effluent quality standards.
(5) Particulate air pollution concentrations can be expected to
increase in future years resulting in continued violation of the
National Ambient Air Quality Standards. The major sources for
particulates will continue to be related to construction activities,
and materials on streets thrown up by vehicular traffic.
(6) With the implementation of a vehicle emission inspection and
maintenance program, carbon monoxide concentrations on a regional scale
will be near to but still exceed standards in 1985. Peak ozone concen-
trations will continue to violate standards for the same year. By the
year 2000, carbon monoxide on an average regional basis will meet
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standards, but high volume traffic corridors and intersections will con-
tinue to have "hot spot" carbon monoxide violations. Peak ozone concen-
trations will be near, but still occasionally exceed standards. The
high per capita usage of the automobile by residents of the Denver region
will continue to be the major source of carbon monoxide, ozone and parti-
culates pollution.
(7) The implementation of any of the three major alternatives or
the recommendations of the Clean Water Plan will likely result in an
improvement in existing stream quality, but not in a degree sufficient
to meet 1983 goals.
(8) The region will experience natural gas supply shortfalls by
1978-1979.
(9) Increased dependence on coal for electrical power generation
will create new water allocation and quality problems.
(10) Energy is not likely to be conserved to the degree necessary
to avoid natural gas supply shortfalls or to reduce the region's
future dependence on coal-generated electricity.
(11) Construction site erosion and runoff will continue to be an
important short-term impact on water quality throughout the region.
(12) Stream channelization and related activities such as diver-
sions and culverting in newly developing areas will adversely affect
the aquatic environment at points throughout the region, particularly
in upstream locations.
(13) Industrial and mining activities along the region's streams
will continue to adversely affect riparian and aquatic habitats.
(14) Continuing development of all types will disrupt riparian
corridors.
(15) Future development in foothill and upland areas will disturb
the habitats and ranges described in Section IV.
(16) A number of unique habitat areas will be disturbed by future
development, overuse of sites, trespassing and vandalism.
(17) The Regional Transportation District will continue having
difficulties competing with the automobile and achieving the utiliza-
tion of its bus fleet until such time the automobile becomes an economi-
cally undesirable means of transportation.
(18) Susceptibility to losses to topsoil and economic losses in
agricultural sector under drought conditions is likely to increase.
(19) Continued development in wind corridors will increase the
potential for Chinook-related damages to some degree.
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(20) Increased traffic volumes on stream valley thoroughfares will
increase the occurence and severity of fog-related traffic problems.
(21) Aesthetically unattractive and potentially hazardous hillside
development is likely to occur in some jurisdictions.
(22) Some significant and unique geologic structures and formations
in the region are likely to be damaged or defaced by overuse and vandal-
ism.
(23) Some mining-related hazards will threaten the safety and well-
being of local residents in some jurisdictions.
(24) Aerosols and local fogs will be produced at the facilities.
(25) Erosion and run-off impacts would likely be unavoidable if
the wastewater treatment plant construction-related mitigation measures
recommended in Section V, Mitigation Measures for Direct Impacts, are
not carried out.
(26) Construction will eliminate human-sensitive wildlife species
from the project sites.
(27) Treatment plant odors should be considered an unavoidable
impact because of the unexpected nature of the climate and operations
upset conditions resulting in their production.
4. Alternatives:
Three strategies for wastewater treatment facilities, and the Clean
Water Plan recommendations were evaluated. The three strategies are
termed Local, Regional, and No-action. The Local alternative strategies
essentially embodies the recommended alternative of each individual
Facility Plan completed or in preparation. This alternative is very
similar to the Clean Water Plan recommendations for wastewater treatment
facilities, which essentially call for the upgrading or construction of
local and satellite wastewater treatment plants. The Regional alterna-
tive calls for the transport of areawide wastes to a central regional
plant for treatment. The No-action alternative is the likely result of
no EPA grant funding for design and construction of wastewater treatment
facilities. The No-action alternative basically involves delays in
the construction of facilities.
5. Distribution:
The list printed at the end of this EIS shows the agencies, groups,
and individuals requested to comment on the draft statement.
6. Draft Statement Sent to Council on Environmental Quality: May 27, 1977.
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CONTENTS
Page No.
I. INTRODUCTION 1-1
BACKGROUND 1-1
ACTIONS UNDER CONSIDERATION IN THIS EIS 1-3
The 201 Facility Plans 1-3
The Clean Water Program (208 Plan) 1-5
THE NEED FOR THIS EIS 1-5
Air Quality and Water Quality Planning Consistency 1-6
Impacts of Growth on Achieving Water Quality Standards 1-7
Prime Agricultural Land Losses 1-8
Sensitive Environmental Area 1-8
Socio-economic Impacts 1-9
Land Treatment and Reuse in the Metropolitan Denver Area 1-9
THE OPTIONS AVAILABLE IN THIS EIS 1-10
THE OBJECTIVES OF THIS EIS 1-10
REPORT ORGANIZATION 1-12
II. THE EXISTING ENVIRONMENT II-l
SITUATION AND DESCRIPTION OF THE DENVER REGION II-l
ENVIRONMENTAL SENSITIVITIES II-2
Regional Climatology II-2
Air Quality in the Denver Region II-3
Effects of Air Pollutants on Health II-4
Effects of Air Pollutants on Crops II-8
Existing Air Quality II-8
Pollutant Emissions in Denver 11-17
Public Concern 11-19
Geology 11-21
Soils 11-21
Hydrology 11-21
Water Supply 11-22
Water Quality 11-24
Biology 11-43
Energy 11-44
Historical Features 11-45
Outdoor Recreation Sites 11-45
Aesthetics 11-46
Waste Land Disposal and Reuse 11-46
Traffic 11-47
Plutonium Contamination 11-49
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SOCIO-ECONOMIC ENVIRONMENT 11-50
Regional Economy, Population and Land Use 11-50
Community Services and Facilities 11-59
Agricultural Land Use 11-63
Regional Planning Policies 11-67
III. THE PROPOSED PROJECTS AND ALTERNATIVES III-l
PROPOSED PROJECTS III-l
BACKGROUND III-l
Alternative and Preferred Non-Point Source Control III-2
Strategies
Alternative and Preferred Wastewater Treatment Facility III-2
Designs
208's Recommended Plan for Municipal Wastewater Treatment III-ll
Plants
EIS ALTERNATIVES - POINT SOURCES 111-13
The Local Alternative 111-13
The Regional Alternative 111-13
The No-action Alternative 111-17
ALTERNATIVES TO STREAM DISCHARGE 111-17
CLEAN WATER PLAN MANAGEMENT ALTERNATIVES 111-19
Point Sources 111-19
Non-Point Sources 111-20
IV. PROBABLE ENVIRONMENTAL IMPACTS IV-1
SOCIO-ECONOMIC IMPACTS IV-1
Regional Population and Economic Impacts IV-1
Community Services and Facilities IV-9
Costs, Financing and Fiscal Impacts IV-10
COST CONSIDERATIONS IV-12
LAND USE CHANGE TO THE YEAR 2000 IV-17
Future Land Use Change IV-17
Regional Development Patterns IV-19
Regional Planning Issues IV-25
Efficiency of Future Development Patterns IV-25
CONVERSION OF AGRICULTURAL LANDS IV-32
Causes of Agricultural Land Conversion IV-32
Agricultural Land Conversion as an Environmental Issue IV-36
Conversion of Agricultural Land in the Denver Region IV-38
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AIR QUALITY IMPACTS IV-42
Introduction IV-42
Modeling Air Quality in Denver IV-43
Data and Assumptions IV-44
Ozone Validation IV-46
Denver Air Quality Projections IV-49
Uncertainty Results IV-52
Effects of Agricultural Crops IV-56
WATER QUALITY IV-58
Background IV-58
The Local Alternatives IV-65
The Regional Alternative IV-67
The No-Action Alternative IV-69
Summary IV-70
GROWTH-INDUCED IMPACTS ON THE REGION'S ENVIRONMENTALLY IV-78
SENSITIVE AREAS
Climate IV-78
Geology IV-78
Soils IV-79
Hydrology IV-79
Biology IV-80
Energy IV-81
Aesthetics IV-81
Outdoor Recreation Sites IV-82
Land Waste Treatment Sites and Wastewater Reuse IV-82
Traffic IV-86
DIRECT ENVIRONMENTAL IMPACTS IV-87
Climate IV-87
Hydrology IV-87
Geology IV-88
Soils IV-88
Biology IV-88
Energy IV-91
Transportation IV-91
Historical and Archaeological Features IV-92
Outdoor Recreation Sites IV-92
Land Waste Treatment IV-94
Aesthetics IV-94
V. MITIGATION MEASURES V-l
MITIGATION MEASURES FOR SOCIO-ECONOMIC IMPACTS V-l
Reduce the Number of Special Districts V-2
Establish a Formal Environmental Review Procedure V-2
Establish Regional Land Use Planning for Major Uses and V-2
Natural Resources
Move Toward a System of Regional Tax-Base Sharing V-2
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Establish a Fiscal Cost/Revenue Balance as a Condition of V-3
Development Approval
Accelerate Development of Parks and Recreation Sites V-3
Discourage Growth in the North and Northeastern Portions V-3
of the Denver Region
MITIGATION MEASURES FOR AIR QUALITY V-4
Mitigation of Growth-Related Air Pollution Emissions Through V-5
Land Use Control of Development Patterns
Mitigation Through a Region-wide Reduction in Emissions V-6
Probable Effects of an Automobile Inspection and Mainten- V-7
ance Program
Possible Effects of a Relaxation of the NO Emission Standard V-8
Control of Particulates from Street Sanding V-9
Implementation of Air Quality Mitigation Measures V-ll
Public Concern V-12
MITIGATION OF WATER QUALITY IMPACTS V-13
Revise Water Quality Goals V-13
Improved Wastewater Treatment V-13
Non-Point Source Control V-14
Development and Growth Controls
A r -i .L -i ~ -
^ ^-*- i-x^uvjv- CU.1U AYC: L. U
Regional Monitoring System
V-15
.. -_ ^.^.^^ V-JL4
Agricultural Reuse and Return Flows V-15
T> • -" - -
MITIGATION OF AGRICULTURAL IMPACTS V-16
Water Conservation V-16
Change Water Laws V-16
Agricultural Land Transfer Tax V-16
MITIGATION OF ENERGY IMPACTS V-17
Natural Gas Shortfalls and Their Effects on Urban and Rural V-17
Users
Secondary Impacts of Natural Gas Shortages on Electrical V-17
Power Generation
Regional Energy Conservation V-17
Energy Use in Wastewater Treatment Plants V-17
MITIGATION MEASURES FOR ADVERSE GROWTH-INDUCED IMPACTS V-19
Climate V-19
Geology V-20
Soils V-21
Biology V-21
Aesthetics V-24
Outdoor Recreation Sites V-25
Land Waste Disposal Sites V-25
Traffic V-26
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MITIGATION MEASURES FOR DIRECT IMPACTS V-26
Climate V-26
Geology V-27
Soils V-27
Biology V-27
Traffic V-29
Historic Features V-29
Outdoor Recreation Sites V-29
Aesthetics V-29
VI. UNAVOIDABLE ADVERSE IMPACTS VI-1
REGIONAL UNAVOIDABLE ADVERSE IMPACTS VI-1
UNAVOIDABLE ADVERSE IMPACTS OF WASTEWATER FACILITY VI-3
CONSTRUCTION AND OPERATION
VII. LOCAL SHORT-TERM USES VERSUS MAINTENANCE AND ENHANCEMENT VII-1
OF THE LONG-TERM PRODUCTIVITY OF THE ENVIRONMENT
VIII. IRREVERSIBLE AND IRRETRIEVABLE COMMITMENT OF RESOURCES VIII-1
IX. COORDINATION AND PUBLIC INVOLVEMENT IX-1
X. SIGNIFICANT ISSUES TO BE RESOLVED X-l
XI. GLOSSARY X-l-7
BIBLIOGRAPHY
DISTRIBUTION LIST
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LIST OF TABLES
Table Page
I-A Facility Plan Regional EIS Environmental Issues and 1-11
EPA Decision Options
II-A National Ambient Air Quality Standards II-5
II-B Maximum Pollution Concentrations Measured During 1974 11-18
and 1975 in Denver
II-C 1974 Denver Emissions Inventory 11-20
II-D Stream Classifications and Allowable Limits for Specific 11-27
Water Uses
II-E Classification by Stream and Reach 11-29
II-F Water Quality Attainability/Use Potential 11-30-32
II-G Wastewater Treatment Facilities Investigated for Their 11-33
Impact on Existing Water Quality
II-H Existing Water Quality (1972) 11-34-35
II-I Comparison of Estimated Point and Nonpoint Source 11-40
Loading in the South Platte and Major Tributaries
II-J Land Waste Treatment Sites 11-48
II-K Demographic Characteristics of Denver SMSA Population, 11-54
1970
II-L Components of Estimated Resident Population Change, 1975 11-55
II-M Distribution of Net In-Migrants to Five Counties, 1970-72 11-56
II-N County Land Use Summary, 1960 & 1970 (1000 acres) 11-58
II-O Summary of Available Information on User Charges 11-61
II-P 1973 Estimates of Agricultural Acreage by Empiric County 11-63
in the Denver Region
II-Q 1973 Estimates by Political County of Existing Agricultural 11-64
Land Within the Region's Major Drainage Basins, but Out-
side the Empiric County Boundaries
II-R Summary of DRCOG Tabulation of Existing and Potential Prime 11-65
Agricultural Lands in a Three County Area of the Denver
Region
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LIST OF TABLES
Table Pa£e
II-S Value of Crop Population by County, 1974 11-66
III-A Current Facility Plan Alternatives III-4-7
III-B Recommended Plan for Municipal Wastewater Treatment 111-12
Plants
III-C Summary of Alternatives 111-14
IV-A Incidence of the Economic Impacts of Growth Generated IV-3
by Increases in the Production of Goods and Services
IV-B Sector Employment Forecast for the Denver Region, IV-6
1975-2000
IV-C Employment Projections for the Five-County Denver Region IV-7
IV-D Incidence of the Fiscal Impacts of Growth Generated by IV-11
an Increase in the Demand for Public Services
IV-E Estimated Aggregate Capital Costs of Wastewater IV-15
Facilities Alternatives (Millions of 1976 Dollars
Through 1983)
IV-F County Land Use Summary, 1970 and 2000 IV-18
IV-G Percentage Distribution of Land by Use Category, IV-20
1970 and 2000
IV-H Regional Subarea Population Allocation by Service Area IV-28
IV-I Population Growth Forecasts for Facility Planning Areas IV-31
IV-J Agricultural Land Use in the Five-County Region: IV-38
1960, 1970 (1,000 acres)
IV-K Projected Year-2000 Agricultural Land in the Five-County IV-40
Region (1,000 acres)
IV-L Anticipated Conversion of Prime Agricultural Land as a IV-41
Consequence of Urban Expansion to Year 2000
IV-M Denver Emissions Inventory (tons per day) for 1985 IV-45
Air Quality Projections
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LIST OF TABLES
Table Page
IV-N Denver Emissions Inventory (tons per day) for 2000 IV-46
Air Quality Projections
IV-0 Denver Air Quality Projections IV-54
IV-P Status of Existing/Proposed Wastewater Collection and IV-59
Treatment Facilities Under the Local, Regional and
No-Action Alternatives
IV-Q Selected Alternative Classification Levels by Specific IV-63
Stream and/or Stream Area
IV-R Water Quality Criteria to Meet 1983 Goals IV-64
IV-S Anticipated Point and Nonpoint Source Loadings in the IV-72
Year 1985 by Stream Basins (pounds per day)
IV-T Percent of Time Desired Water Quality Cannot be Achieved IV-75
by Point Source Controls Alone. Classification Level 4
IV-U Percent of Time Desired Water Quality Cannot be Achieved IV-76
by Point Source Controls Alone. Classification Level 3
IV-V Control Requirements for Point and Nonpoint Sources IV-77
V-A Energy Conservation Mitigation Measures V-18
V-B Energy Conservation Measures for Wastewater Treatment V-17
Facilities
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LIST OF FIGURES
Figure Page
I-A Relation of Denver Region to the State of Colorado 1-2
II-A Air Quality Monitoring Stations II-9
II-B Number of Days in 1974 Stations Recorded Levels Exceed- 11-10
ing Standard
1I-C Days Carbon Monoxide Exceeded Standard 11-12
II-D Carbon Monoxide Levels Compared with Traffic Volume 11-13
II-E Ozone Formation 11-14
II-F Number of Days in 1974 Stations Recorded Levels Exceed- 11-15
ing Standard
II-G Days Ozone Exceeded Standard 11-16
Il-fl Water Supply System Denver Water Department 11-23
II-I Primary Area Water Supply and Demand 11-25
II-J Land Waste Treatment Sites 11-48
II-K Regional Employment and Population by County 11-53
III-A Schematic of Local Alternative 111-15
III-B Schematic of Regional Alternative 111-16
IV-A Regional Employment and Population by County IV-8
IV-B Future Service Areas IV-23
IV-C The Variation of Averages over all Stations of IV-48
Observations and Predictions
IV-D Average Projected Particulate Concentrations 1974 to IV-53
2000
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ACKNOWLEDGEMENTS
EPA Region VIII wishes to gratefully acknowledge the assistance
of Engineering-Science, Inc., in preparing this EIS, and Systems
Applications, Inc., for the analysis of Denver's future air quality.
The assistance of Engineering-Science's subcontractors, Gruen Gruen &
Associates, and Leonard Rice Consulting Water Engineers, is also
gratefully acknowledged.
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I. Introduction
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SECTION I
INTRODUCTION
The Denver metropolitan area includes nearly 60 percent of the
population of the State of Colorado. It is located geographically near
the middle of the state where the eastern plains of Colorado meet
the Rocky Mountain foothills (see Figure I-A and Map A).
BACKGROUND
In 1969 a law of far-reaching significance for Federal agencies
was passed by Congress. This law, called the National Environmental
Policy Act (and referred to as NEPA), requires a Federal agency to
take account of and make known the environmental impacts of any major
action it is about to undertake. The agency must decide whether a
given action is a major one that will have a significant effect on the
environment. The document that a Federal agency must prepare on such
a major action is called an environmental impact statement (EIS).
The Environmental Protection Agency (EPA) is responsible for
seeing to it that many of the environmental laws passed by Congress
are put into effect; however, it is also one among many Federal
agencies which must also comply with NEPA in its own actions.
In 1972, EPA became responsible for implementing the Water
Pollution Control Act Amendments (P.L. 92-500). This law among other
things established water quality goals for U.S. Waters:
1. "...wherever attainable, an interim goal of water
quality which provides for the protection and propagation
of fish, shellfish, and wildlife and provides for recreation
in and on the water be achieved by July 1, 1983," and
2. "...that the discharge of pollutants into navigable
waters be eliminated by 1985."
The law set up a comprehensive planning process involving EPA
and the State to define the necessary stream water quality standards
and treatment levels to achieve these goals, and how they would be
attained. The law created the National Pollutant Discharge Elimination
System (NPDES) of permits to regulate and control discharges to the
Nation's streams. Congress also set aside $18 billion in grant funds
to pay 75% of the eligible costs of publicy owned waste treatment
works to assist municipalities in achieving the necessary plant
1-1
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•DENVER
COLORADO
Scale 1:500,000
10 0
10 Miles
10 o
t-i i_i M 1-1 1-1 I-
10 I Kilometers
RELATION OF DENVER REGION
TO THE STATE OF COLORADO
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effluent quality to meet the water quality goals.
The Environmental Protection Agency is charged with overseeing
most of these and "her provisions of the Act. Two areas of EPA
responsibility under the Act are brought together in this EIS effort.
Section 201 of the Act provides for a three-step facilities plan-
ning, design, and construction approach to secure Federal funds for
municipal wastewater treatment works. Step I involves the development
of a "facilities plan" that evaluates treatment needs, systems capa-
cities, alternatives, and develop a preliminary design for the project.
EPA is charged with review and approval of such Step I plans before
design (Step II) and construction (Step III) funds can be obtained.
An integral part of the EPA's review involves an assessment of environ-
mental impact that the facility plan defines.
Section 208 of the Act is also administered by EPA. This is a
special planning function that analyzes complicated water pollution
problems on a regional or Statewide scale. Where the Governor of a
State identifies a major water pollution problem, a 208 agency is
designated to develop this comprehensive planning approach to the prob-
lem. 208 planning involves defining point and non-point sources waste-
load projections, treatment needs and priorities, a closer evaluation
of stream classification, the necessary controls and the type of man-
gement to achieve the goals of the Act. Such a plan in effect will set
many of the criteria to be developed in individual 201 facilities plan
for the study area.
ACTIONS UNDER CONSIDERATION IN THIS EIS
The 201 Facility Plans
Various local agencies have prepared or are developing facility
plans to construct, improve and/or expand municipal wastewater col-
lection and treatment systems for the following planning areas (see
Map J) :
1. South Adams County
2. Englewood and Littleton
3. South Lakewood
4. Cherry Creek and Goldsmith Gulch
5. Lower South Platte
6. Clear Creek and Sand Creek
7. Westminster and Broomfield
8. Metropolitan Denver Sewage Disposal District No. 1
1-3
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Each of these wastewater treatment facility plans must iden-
tify the most cost-effective and environmentally sound alternative
after considering the local and regional implications of the pro-
ject. Considered together, these projects raise significant re-
gional issues which must be addressed, such as population levels
and distribution, air quality, conversion of agricultural land,
protection of environmentally sensitive areas, point and non-point
pollution control, etc. There has been a great deal of discus-
sion lately between citizen groups and various levels of government
concerning the best way to address these regional issues. A re-
gional environmental study has been developed as one possible way
to evaluate these issues. EPA's policy in the past has been to
evaluate wastewater treatment facility plans in the Denver metro-
politan area on a project-by-project basis and to prepare the
individual project environmental impact statements, if necessary.
The analysis of regional issues and secondary impact questions
has been difficult using a project-by-project approach. EPA ac-
knowledges this difficulty in the final EIS for the present plant
expansion by the Metropolitan Denver Sewage Disposal District No.
1 (February, 1974), in the final EIS for the Englewood-Littleton
sewage treatment plant (August, 1974) and in the negative declara-
tion for the South Platte II interceptor sewer (September, 1975),
where EPA indicated the intention to prepare a regional environ-
mental impact statement addressing these broader issues.
As indicated above, there are other wastewater treatment
projects that are in various stages of construction, some of
which have been the subjects of individual EIS's. Although not
directly affected by the EIS effort, it is EPA's intention to
apply any reasonable mitigating measures to any of those projects
beginning or still under construction. The on-going Denver area
projects not directly covered in this EIS are as follows:
1. City of Boulder's wastewater treatment plant improve-
ment program with EIS now in preparation;
2. City and County of Denver's interceptors in the Har-
vard/Jewell area, which are now under construction;
3. City and County of Denver's parallel Delgany Inter-
ceptor and Storm and Sanitary Sewer Separation pro-
jects to be constructed;
4. City of Westminster's Big Dry Creek Plant expansion
now being designed;
5. Metropolitan Denver Sanitary Disposal District No. 1
(MDSDD No. L) central plant expansion now under con-
struction;
1-4
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6. MDSDD No. 1 sludge disposal plan now being finalized for
funding;
7. New regional plant and interceptors for Littleton and Engle-
wood now under construction; and
8. MDSDD's Platte River II Interceptor now under construction.
The Clean Water Program (208 Plan)
The Denver Regional Council of Governments (DRCOG) was designated
the 208 study agency for the Denver area to address the complicated
water pollution problems in this highly urbanized area.
The DRCOG 208 study, named the Clean Water Program, has evaluated
the national goals and their attainability in the Denver area with
respect to financial, environmental, social and economic impacts. It
has also attempted to determine technical solutions to regional
environmental problems and recommended a management system for imple-
menting the clean water plan. The draft of the 208 plan-was .released
in April by DRCOG. The final plan must be developed and approved by
July 1977.
As an integral part of the work effort of the 208 plan, population
allocations and a land-use plan have been developed by DRCOG, as well
as a set of recommended treatment plant funding priorities and levels
of quality for plant effluents. An assessment of the non-point source
problem as it affects meeting the national goals is also included in
the plan.
Since this information is germaine to the individual facility
plans and since EPA must review and approve the 208 plan under National
Environmental Policy Act criteria, this EIS will also cover relevant
portions of the 208 plan.
THE NEED FOR THIS EIS
As mentioned briefly, EPA is concerned about the piecemeal
manner in which its NEPA reviews of earlier projects have proceeded.
Regional or secondary impacts simply could not be adequately discussed
at the project level.
It now appears time to prepare a regional environmental impact
statement which analyzes various regional issues associated with waste
water facility plans. The preparation of a regional environmental
impact statement will expedite Federal funding in the longer term and
substantially reduce the need for environmental impact statements on a
project-by-project basis. More importantly, the approach will permit
local governments and the citizenry to address these significant
1-5
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regional issues.
Air Quality and Water Quality Planning Consistency
The regulatory aspects of EPA's activities under the Clean
Air Act relating to transportation control plans to achieve air
quality standards may not require a NEPA evaluation. However, EPA
has come to realize that activities in different media programs (here
air and water pollution control) need to be consistent.
The Denver Air Quality Control Region (AQCR) is currently in
violation of ambient air quality standards for carbon monoxide, parti-
culates, and ozone. A transportation control plan (TCP) has been ad-
opted by the Colorado Air Pollution. Division, Department of Health and
EPA. Implementation of the various control strategies to date has
been very limited and air quality standards will continue to be
violated for at least several years even with controls.
A court decision (NRDC vs EPA) required EPA and the States to up-
grade their State Implementation Plans to attain air quality standards,
and to develop plans to maintain standards once attained. Thus the
present TCP for Denver will have to be improved to provide for main-
tenance of air quality. At present, the Air Quality Maintenance Plan
for Denver AQCR is being analyzed. The latest available modeling
indicates that it is very doubtful that additional strategies, which
may be added to the original TCP, would result in attainment of air
quality standards by 1983 because of existing emissions and future
population growth would offset their effectiveness.
The principal source of both carbon monoxide and ozone (formed
from hydrocarbon emissions) is the automobile. This is why the
transportation control plan has been developed for the Denver AQCR.
Using historical trends, we can be reasonably confident that there
is a linear relationship between additional population and increase
in vehicle miles travelled (VMT).
In regard to facility planning, the environmental issue of note
becomes this: to what extent does the population growth planned in for
sewage treatment plant and interceptor capacity relate to further VMT
growth in the metropolitan Denver area? Is the planning for treatment
plant capacity consistent with AQMA plans? Among other, probably more
acceptable, strategies the Clean Air Act does provide for land-use
controls if necessary, to achieve and maintain air quality standards.
Thus it was felt necessary to look at projected population growth in
terms of a) total growth, b) the distribution of this growth and to
a certain extent c) how future development patterns would be organized
to determine its impact on air quality. Such projections for growth,
size, and distribution are, of course, an essential element of fa-
cilities planning for sewers and wastewater treatment plants. EPA
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feels that its approach in these two areas of environmental protection
must be consistent.
Impacts of Growth on Achieving Water Quality Standards
Planning for future growth means, of course, that more sewage and
other forms of water pollution must he accounted for and controlled.
In particular, non-point sources (those diffuse pollution sources not
developed or relased at a definable single point on a stream or lake
—e.g. stormwater runoff, agricultural return flows, lawn watering,
car washing, etc.) must be accounted for in calculating the total
impact on stream quality. Estimates of future growth must evaluate
not only the incremental burden of domestic usage to streams, but
the added non-point source growth increments as well.
In order to properly plan for wastewater treatment facilities, one
must know:
a. What degree of treatment is necessary at the plant.
b. What are the other sources on that stream reach which also
contributing to the problem.
c. How can they be controlled and
d. What is the likelihood and cost of attaining stream standards
required under the Act.
The 208 study in progress by DRCOG has been under development at
the same time as the preparation of the facility plans. However,
decisions on facility plans such as degree of treatment, type of
treatment, location, population impacts, etc., must have the benefit
of the overall 208 study. This EIS is an attempt to bring together
these disparate studies for EPA's evaluation of the total water quality
picture for the Denver metropolitan area.
Relationships of Wastewater Treatment Plant Organization
Sixteen wastewater treatment projects are undergoing planning or
construction at this point in time in the contiguous Denver metropolitan
area. Virtually all-of the separate facilities planning is inter-
related in some fashion. Decisions on the smaller upstream plants
CSo. Lakewood, Cherry Creek, Clear Creek, Sand Creek, So. Adams)
invariably involve maintenance or development of an upstream facility
versus connection with a downstream facility (Denver Northside, Metro,
etc.). In some cases (Westminster, Lower South Platte) potential
decisions may involve a redistribution of flows between the separate
districts. It is thus important to consider these individual options,
together and a common point in time. It may also be possible to
develop an overall policy consistent with other needs of the State
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(water rights, re-use, instream benefits) concerning satellite
versus centralized treatment.
Prime Agricultural Land Losses
This is a special land-use problem that is not only a regional
problem, but a national one. The Council on Environmental Quality,
rightly concerned with the problem, commissioned a special study to
analyze the impacts of urban growth on the nation's farmlands. The
study demonstrated that the prime agricultural land is rapidly being
converted to urban uses. In a qualitative way, EPA has been aware
of similar problems in the Denver metropolitan area. Virtually all
new housing development in the metropolitan area uses some form of
agricultural land. The land could vary from rangeland to dryland
farming, to irrigated farmland.
The relationship between this loss of agricultural lands and
facility planning is as follows: The projections used in facilities
planning of how much new population and where population will go will
have a strong effect on the amount of farmland lost.
This is one more area in which EPA and other agencies have little
information with which to make a decision. Facility plans to date
have not catalogued how much of the various categories of farmland will
be eaten up by the projected developments. Therefore, EPA cannot
estimate the magnitude of the problem except in general terms. This
EIS will investigate on a regional level, how many of the various
categories of farmland acreage will be lost to projected developments,
how critical in terms of the overall State and national farming
economy the loss of these lands are, and whether any specialty crops
are involved that cannot or are not likely to be grown elsewhere. Only
with this information can a set of reasonable strategies be offered for
mitigating such land losses in facility planning.
Sensitive Environmental Area
In planning for future growth, planners need to be aware of the
potential impact of new population on environmentally sensitive areas
unsitable for development. Such a list of features would include:
* unusual geological features
* archaeological features
* historical features
* floodplains
* marshland/wetlands
* wildlife habitat areas
* natural vegetation areas
* steep slopes/unstable soils
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The first problem is to recognize the commonality of these items
from one service area to another. Many of the items in a given service
area represent only a fraction of the total resources» There is a
need to look cumulatively at the entire Denver metropolitan region to
assess how vulnerable these resources are. The EIS in conjunction with
the 208 information will be developing an environmental sensitivity
inventory that can give EPA an overall picture of the situation. Each
of the items above fall under different spheres of control and would
have to be handled differently. As a policy, EPA could insist that
maximum protection under current law be given to areas identified as
important. Hopefully, the EIS will be able to develop a comprehensive
strategy to deal with these areas in all facility plans.
Socioeconomic Impacts
This is an area that has received very little attention in past
EIS efforts on wastewater facilities. The EIS will attempt to identify
any sociological or economic impacts both beneficial and adverse,
that could occur because of the overall Federal investment pattern of
construction grants in the Denver metropolitan area, The ETS will
pay particular attention to the problems involving suburban districts
versus the central city facilities and the potential influence that
this Federal Funding program may have on urban form.
Land Treatment and Reuse in the Metropolitan Denver Area
EPA is required to consider land application and reuse of waste-
water as potentially benefitical ways of achieving water quality stan-
dards and attaining other valuable environmental objectives (farmland
protection use of nutrients, etc.) Until now, land treatment has received
limited evaluation in facility plans. Land treatment involves the dis-
charge of treatment plant effluent onto the land surface where percola-
tion through and interaction with the soil removes pollutants. The
first comprehensive water quality management study (called the 303 (c)
plan) for the Metropolitan Denver area eliminated land treatment because
of the high cost. The 208 study is reevaluating the potential for land
treatment and reuse in the study area.
Because of the scarcity of water in Colorado for all uses (mumi-
cipal, industrial, agricultural), interest has grown in many Colorado
communities in instituting some form of water reuse. Particularly in
the fast growing areas, municipalities may be able to increase their
domestic water supplies through an arrangement of "first use" by muni-
cipalities and use of wastewater effluent by agricultural concerns.
Colorado water rights laws dictate to a large extent what kinds of
"reuse" schemes are available to communities,
The effects on water quality may be beneficial, but it is not
necessarily true in every case. Streamflows can be depleted as well
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as augmented. It will depend to a large extent on the type of reuse
system involved. The issues involving plant organization are in
some ways related to this issue. In this EIS, then, EPA will define
the types of potential reuse systems, the specific situation as it
occurs in Colorado, and impacts likely to occur for different systems.
Eventually, decisions on the most beneficial types of reuse from a
water quality standpoint may be influential in determining the sate-
llite-regional plant arrangements,
THE OPTIONS AVAILABLE IN THIS EIS
The foregoing are issues that EPA identified that suggested a
need for a regional EIS. This EIS also identifies and evaluates
to the extent possible any other relevant and significant issues
that have been concerned in the process of developing this EIS,
The EIS will also identify on a cumulative basis, direct impacts
common to all facility plans. This regional EIS on 8 wastewater
facilities and the Clean Water Program is not an attempt to define
the environmental "carrying capacity" for the Denver Metropolitan
Area. One set of population and land use assumptions are utilized
for the evaluation of the various topics. Consistent with the
DRCOG forecasts and the Clean Water Program, a population of 2.35
million is assumed for the year 2000 as is the adopted regional land
use plan.
Recommendations for mitigation as a result of the analyses in this
EIS could involve changes to the facility plan or potential require-
ments on grants for design and construction. Table 1 depicts a matrix
of possible areas of facility plan development that could be affected
by the different impact (issue) analyses.
THE OBJECTIVES OF THIS EIS
As an overall perspective, the following general objectives were
identified for this EIS based on the above discussion.
(a) To define and assess the environmental impacts of the eight
Denver metropolitan wastewater facility plans and the
secondary impacts of the 208 Clean Water Program.
(b) To define EPA policy and decision options for assurance of
consistency between EPA'a Air and Water Programs and the
goals of NEPA, including the options for mitigation of
adverse secondary impacts,
(c) To stimulate public discussion about "desirable" environ-
mental goals for the Denver metropolitan area, with em-
phasis on the relationship of EPA's construction grants
program to other Federal State, Regional and local govern-
mental programs.
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Table I-A. FACILITY PLAN REGIONAL EIS ENVIRONMENTAL ISSUES
AND EPA DECISION OPTIONS*
REGIONAL ENVIRONMENTAL ISSUES
OPTIONS AVAILABLE
TO EPA UNDER THE
CONSTRUCTION GRANTS
PROGRAM
Treatment Plant
Capacity and Timing
Alternative
Systems
Type of Treatment
(Design)
Extent of
Treatment
(Levels)
Location of Plants
and Interceptors
Air
Quality
Impact
X
Water
Quality
Impact
X
X
X
X
Plant Agri- Sensitive Socio-
Organi- cultural Environ- economic
zation Land Mental Area Impacts
Loss Impacts
X
X
X X
X
Regional
Alterna-
tives
X
X
Special Grant
Requirements for Step
II and Step III Projects
X
X
X
X
X
X
X
X
X
X
X indicates where there may be a likely decision option.
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The latter point deserves some further elaboration, EPA has
extensively coordinated the preparation of this EIS with various
state, local and federal agencies. Some of these agencies have
performed or have embarked on studies which are pertinent to this
EIS and the issues it addresses, For example, this EIS makes ex-
tensive use of information, data, and analysis developed by the
Denver Regional Council of Governments and its consultants for the
208 planning effort. The U. S. Department of Housing and Urban
Development has initiated an EIS on its FHA housing program for
Denver, and the U.S. Bureau of Land Management will soon complete
a revision to its draft EIS on the proposed Foothills Water Treat-
ment Plant. In terms of growth related environmental issues, the
EPA EIS emphasizes areas of EPA responsibility such as air and water
quality, and is intended to supplement work by other agencies. Thus
it is hoped that this EIS will help provide a focus for confronting
growth related environmental issues of much concern to the State of
Colorado and the citizens of the Denver region.
REPORT ORGANIZATION
This report is organized into a progressive sequence of discus-
sions addressing issues which EPA must resolve. EPA must take a
series of decisions about the most effective way to spend resources
(grant funds). These resources, though large, are limited. EPA
has several options concerning the level of treatment of wastewater,
which pollutant discharges are most important, what wastewater treat-
ment plan flow capacities are most appropriate, what standards are
appropriate to meet water-use goals and others. The environmental
consequences of these options are an integral part of this draft
Environmental Impact Statement. This draft EIS, together with the
public review and input it will stimulate, will form the basis for
a final EIS which will address the environmental effects of possible
EPA actions as best as can be determined.
The following section of this report discusses the current
environment in the Denver region. What environmental problems now
exist or are anticipated, giving existing trends, are also addressed.
Next, the project proposals which have been or are anticipated to
be submitted to EPA are presented and discussed. These actual and
anticipated proposals are then organized into three broad alternative
strategies or courses of action which EPA may take. Subsequent dis-
cussions in this draft EIS plus public review and input will modify
and evolve one of those alternative strategies into a course of
action best suited for the maintenance and inhancement of the en-
vironment. The discussions of impacts, means of mitigating impacts,
impacts that can't be avoided, short-term uses of the environment
versus long-term environmental productivity, and irreversible
commitments of resources are presented in this draft EIS as a first
step in the evolutionary process.
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XI. The Existing
Environment
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SECTION II
THE EXISTING ENVIRONMENT
SITUATION AND DESCRIPTION OF THE DENVER REGION
The study area for this EIS is shown on Map A*. The semi-arid
Denver region is located at the approximately 1,600 m (5,280 ft) high
western edge of the high plains province of Colorado. This portion
of the Great Plains slopes upward 585 m (1,930 ft) for almost 300 km
(186 miles) from the 1,020 m (3,350 ft) high eastern state boundary to
the abruptly rising foothills at the base of the Rocky Mountains.
Relief is characterized by rolling prairie with some hillg and ridges
intersected by level flood plains along the generally northeast
flowing watercourses of the Platte River drainage. The South Platte
River and Cherry Creek flow through the heart of Denver.
Approximately 1.5 million people (1975) live in the region
(Reference 126). Regional growth reached a peak rate of 5.5 percent
per year in 1972-73 and has since declined to a rate close to the
1960-70 average of 2.6 percent. Population distribution patterns are
changing as the central city continues to lose population to the
suburbs (see Map B). Residential areas and their service facilities
surround the commerce areas with densities decreasing with distance
from _the urban core to the suburban/rural edge of the region.
Denver is the state capital and is the major Federal administra-
tive center for the Rocky Mountain States. Government employment is
considerable with thousands of people employed by the state, the
Rocky Mountain Arsenal and other government facilities. Transportation
industries such as aviation, trucking and railroads are of major
importance to the region's economy due to Denver's crossroads situa-
tion for many transportation routes. Commercial and industrial
enterprises are concentrated in the urbanized areas with many of them
located in the Denver downtown area and along major streams. Mineral
extraction industries are also found along the region's streams.
Agricultural activity is a significant part of the region's economy-
*A11 maps referred to can be found in the Map Folder supplied with
this report.
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ENVIRONMENTAL SENSITIVITIES
EPA's purpose for this EIS is to examine the effects and issues
of growth in the Denver area so that it might determine whether or not
it should contribute to the accomodation of this growth through its
wastewater funding programs. Also, EPA must consider its administra-
tive responsibilities in terms of the regional environment and
promote programs and strategies for dealing with physical environmental
problems such as air and water quality. To examine these effects and
issues, a mass of data and information on the Denver area for this
EIS has been edited to emphasize the major characteristics of the
region that may affect or be affected by the proposed projects and by
growth. A more lengthy and detailed presentation of general physical,
biological and cultural characteristics of the region can be found in
Appendix A.
Regional Climatology
Appendix Table A-l provides a specific data summary for the
following general discussion.
The Denver region, lying at the western edge of the Great Plains
near the Rocky Mountain foothills, is in an area of transition between
the climate of the plains and that of the mountains. The region is
situated within an area having, overall, a high-altitude, continental
climate. Locally, the region's climate is that of semi-arid steppe.
Temperatures are generally moderate. The growing season is
approximately five to six months long. Precipitation is relatively
light, with a large portion falling during the April-September growing
season. Much of the summer precipitation occurs as a result of
thunderstorm activity, and heavy thunderstorms in the eastern foot-
hills and plains area occasionally cause flash floods. Snowfall is
generally not heavy. Extensive flooding caused by snowmelt in the
nearby mountains occurs only at times when there has been either a
heavy accumulation of snow or sudden high altitude warming. The
generally low relative humidity is a major factor in the region's
somewhat high annual evapotranspiration rate which is twice the
average annual precipitation.
Denver experiences high winds. The wind data presented in
Appendix Figure A-l for Stapleton Airport on the northeast edge of
Denver are representative of the region. Denver also experiences
infrequent and often destructive "Chinook" winds from the northwest
during fall through spring. Chinooks with velocities of up to
54 meters per second (120 mph) blow down from high-elevation westerly
winds warmed by compression during their rapid descent through the
shallow layer of cool air covering the plains. The sudden rises in
temperature resulting from these gusty winds exert a moderating
II-2
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influence on winter temperatures. Chinooks are experienced in a
24-32-km (15- to 20-mile) wide zone along the foothills. Although
little information has been published which identifies areas of
greatest wind velocities, it is recognized that winds during Chinook
events are 3-5 mph higher along the bottoms of the stream valleys than
in the surrounding areas. Therefore, wind damages are also generally
greater in the stream valleys. Ridges which experience higher than
average wind velocities during Chinook events are shown on Map C.
Construction activities are generally restricted during Chinook events
and wastewater treatment processes involving spraying are generally
curtailed (Reference 126, 413).
During the winter and spring, early morning, local radiation fog
conditions are common along the low-lying stream valleys, particularly
near irrigated parklands and farms, large bodies of water, and waste-
water treatment plant lagoons. Because many of the major transporta-
tion routes are situated in the stream valleys where most fog-
contributing water sources are located, fog conditions often impede
commuter traffic.
Air Quality in the Denver Region
The following discussion will first present aspects of the climate
in the Denver region which affect air pollution levels. Next, short
discussions of health effects and effects on agricultural crops are
presented. The next sections will discuss current air quality and
the sources of air pollutants. The last section in the air quality
discussion presents some available on public concerns about air
quality.
Climatic Conditions—
Air quality in the Denver area is influenced primarily by the
South Platte River Valley and its associated drainage winds that move
down the valley to the northeast during the evening and then reverse
approximately mid-morning with upslope motion occurring during most
of the remainder of the daylight hours. As the air flows across the
city, pollutants generated at the surface are transported back and
forth over the area increasing and decreasing the pollutant concentra-
tion. Fortunately, Denver's location on the east side of the Rockies
means that the containment of a pollutant cloud during generally
prevailing westerly winds does not occur as, for example, happens in
Los Angeles.
Solar radiation plays an important role in determining air
pollution potential. The ultraviolet component of sunlight is the
driving force that initiates the chemical reactions necessary to
produce photochemical smog. Denver, at its "mile high" altitude,
receives a higher amount of ultraviolet radiation because the thinner
atmosphere doesn't filter out as much ultraviolet radiation.
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Normally, the temperature of the air decreases with height above
ground surface. When the opposite occurs, or temperature decreases
with height, upward movement of cold surface air is restrained by
the "lid" of warmer air aloft. This condition is called an inversion.
The altitude or depth of this inversion, in hundreds or thousands of
feet, determines the volume of air in which air pollutants are mixed
and how concentrated they become. Denver is very unusual because no
city of comparable size in the nation has a lower morning inversion
or a higher afternoon inversion. This means that air pollutants
emitted in Denver's morning rush hour are trapped in a very thin layer
of air. However, by afternoon, the volume of air has increased
drastically as the inversion rises, and pollutants are thereby great-
ly diluted.
Effects of Air Pollutants on Health—
The Clean Air Act Amendments of 1970 mandated that minimum
standards of air quality be set to protect the public health and
welfare of the population at large. The law requires that primary
standards be set to protect the public health with an adequate margin
of safety, and that secondary standards be set to protect the public
welfare. Effects on public welfare are concerned mostly with plant
and property damage.
The EPA after a great deal of research set standards for five
pollutants. These are Carbon Monoxide (CO), Photochemical Oxidants
(usually characterized as Ozone), Sulfur Oxides (SOX),, Nitrogens Di-
oxide (N02)» and Total Suspended Particulates (TSP)- Standards for
all but Sulfur Oxides are shown in Table Il-A, the health effects
of these pollutants are discussed below. Sulfur Oxides are not dis-
cussed in this EIS as they are not currently a problem in the Denver
region.
Carbon Monoxide—Carbon monoxide (CO) is a colorless, odorless,
tasteless gas commonly found in our urban atmosphere in concentra-
tions that can be harmful to people. It is a by-product of combus-
tion, and the greatest single source of this pollutant is the auto-
mobile.
Carbon monoxide is inhaled through the lungs and enters the
blood stream by combining with hemoglobin, the substance that nor-
mally carries oxygen to the cells. CO combines with hemoglobin much
more readily than oxygen does. The result is that the amount of
oxygen getting to the tissues is drastically reduced in the presence
of CO, and this can have a profound effect on health. CO also impairs
heart function by weakening the contractions of the heart which sup-
ply blood to the various parts of the body. The effect of this on
a healthly person is to reduce significantly his ability to perform
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TABLE II-A. NATIONAL AMBIENT AIR QUALITY STANDARDS'
Pollutant
Particulate matter
Carbon monoxide
Nitrogen dioxide
Photochemical oxi-
dants
Averaging Primary
Time Standards
Annual (geo-
metric mean)
24 hourb' c
8 hour
b
1 hour
Annual (Arith-
metic mean)
b
1 hour
,, 3
75 ym
3
260 yg/m
3
10 mg/m
(9 ppm)
40 mg/m
(35 ppm)
3
100 yg/m
(0.05 ppm)
3
160 yg/m
(0.08 ppm)
Secondary
Standards
3
60 yg/m
3
150 yg/m
3
10 mg/m
(9 ppm)
40 mg/m
(35 ppm)
3
100 yg/m
(0.05 ppm)
3
160 yg/m
(0.08 ppm)
Hydrocarbons
(nonmethane)
3 hour .j 3
(6 to 9 a.m.) 160 yg/m 160 yg/m
(0.24 ppm) (0.24 ppm)
aThe air quality standards and a description of the reference
methods were published on April 30, 1971, in 42 C.F.R, 410,
recodified to 40 C.F.R. 50 on July 1, 1975.
Not to be exceeded more than once per year.
CState standards for particulate matter;
o
24 hour, 150 yg/m ; Annual, arithmetic mean, 45 yg/m.
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exercise, but in a patient with heart disease, who is unable to compen-
sate for the decrease in oxygen, it can be a life-threatening situation.
A person who has a heart attack in the presence of heavy carbon monoxide
air pollution is more likely to die than if the attack had occurred in
clean air. And carbon monoxide is also harmful to person who have lung
disease, anemia, or cerebral-vascular disease.
Carbon monoxide can also affect mental function at relatively
low concentrations of 30 parts per million (ppm). Visual perception
and alertness can be affected.
Ozone—Photochemical oxidants are responsible for a number of
health effects in humans. They can affect the lungs and eyes. They
may result in eye irritation with the familiar symptoms of tears and
inflammation. At certain concentrations they have been shown to im-
pair the performance of athletes, and to affect persons with asthma.
Ozone, the main constituent of photochemical smog, is a severe
irritant to all mucous membranes, and its main health effects are on
the respiratory system. It is verturally intolerable at levels of 1
part per million. At considerably lower concentration (0.1) to 0.2
ppm) which often occur in the air of many American cities, ozone in
conjunction with other photochemical oxidants causes a variety of
health effects which are aggravated by exercise. Ozone also has an in-
creased effect on respiratory function in the presence of sulfur di-
oxide.
Nitrogen Dioxide—Oxides of nitrogen usually originate in high-
temperature combustion processes, such as in auto engines, and to a
lesser extent in chemical plants.
Although measurement of this pollutant in the atmosphere is
difficult, experience has shown that in various forms, oxides of
nitrogen can affect humans as well as materials and vegetation.
Based on occupational exposures to nitrogen dioxide by firemen,
welders, silo fillers, miners, chemists, and other industrial workers,
we know that a high concentration of this pollutant can be fatal to
humans. At lower levels of 25 to 100 parts per million, it can cause
acute bronchitis and pneumonia.
The group of pollutants known as nitrogen oxides also can affect
lung tissue and lower the resistance of laboratory test animals to
influenza. Scientists suspect the same effect may occur in humans.
In one study of schoolchildren living near an industrial plant pro-
ducing nitrogen dioxide, an increase in respiratory disease was noted.
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Oxides of nitrogen also can react with hydrocarbons, in the
presence of sunlight, to form photochemical oxidants which, as
noted elsewhere, can affect human lungs and eyes as well as
cause respiratory irritation.
Total Suspended Particulates—Total suspended particulates
(TSP) is a term for the measurement of all particles in our air,
including soot, mists, and sprays. TSP includes a wide range of
non-toxic materials such as dust and dirt, and many other mate-
rials that we know or suspect to be toxic, such as beryllium,
lead, asbestos, certain hydrocarbons which may be carcinogenic,
suspended sulfates and nitrates, and possible, radioactive ele-
ments.
The amount of toxic materials in our air will vary geo-
graphically, depending on the man-made and natural sources in a
particular area. To date, few studies have been conducted on
the health effects of individual particles because of the wide
range of differences in the makeup of particulate concentrations.
Particulate matter is studied for the most part as a single con-
taminant, and most studies relate particulate concentrations
to death, respiratory illness, and breathing problems in urban
industrial areas where energy supplied by fossil fuel consumption
is a major concern.
The effects of particulate air pollution on health are
related to injury to the surfaces of the respiratory system,
that is, to the linings of the lungs and throat. Such injury may
be temporary or permanent. It may be confined to the surface.
However, by weakening resistance to infection, such pollutants
may affect the entire body adversely. Chemical carried into the
lungs by particulates, for example, may cause cancer to develop
on the lung lining, which then may spread throughout the body
and prove fatal. Inhaled lead particulates may cause lead poison-
ing—manifested by nervous and blood symptom—while causing very
little damage to the lung itself.
In studies of air pollution in London and New York City, a
rise in the number of deaths has been recorded when both smoke and
sulfur oxides levels were high. Studies in Buffalo and Nashville
also showed increased death rates, particularly among older persons,
where combined pollution from particulates and sulfur oxides were
recorded. Eye irritation from dust particles also can be a problem
in many areas.
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Effects of Air Pollutants on Crops—
The effects of air pollutants on crops have been subject
to Investigation for nearly thirty years. However, the state
of knowledge is not as complete as for effects on people.
Pollutants can damage crops by stunting growth and by causing
physical changes of a type similar to those caused by pests
and plant diseases. The stunting of growth reduces the yield
per acre and the visible damage reduces the marketability
particularly for crops destined for supermarket shelves.
The air pollutants of major interest nationally are oxi-
dants, sulfur dioxide, and fluorine compounds. The last two
pollutants are characteristic of certain type of point sources
and are not of concern at this time in the Denver region. Oxi-
dants, primarily ozone, are the pollutants of primary concern
in the Denver region. Crop damage caused by zone is not a
straightforward function of ozone concentration. The degree
and type of damage depends on the crop as well as climate.
Different varieties of crops, e.g. different hybrids of corn,
having varying sensitivities to ozone. Of two varieties of
corn exposed 50% of the time to oxidant concentrations of 8
parts per hundred million (pphm) or more during daylight hours,
one was found to have little significant damage, while the
other variety had significant reductions in the number and
size of ears produced (Reference 993). The crops most sensi-
tive to oxidants are alfalfa, barley, beans, clover, hay, oats,
potatoes, rye, soybeans, sugarbeets, all types of citrus, and
leafy vegetables. As many of these crops are grown in the
Denver Region, air pollutant effects on agricultural productivity
are of potential significance.
Existing Air Quality—
Since 1974, the Colorado Department of Health has had
six continuous monitoring stations in operation in the Denver
area. The location of these monitoring stations is shown in
Figure II-A.
Figure II-B shows the number of days that CO standards
were violated in 1974 at these monitoring stations. The CAMP
station is in the heart of Denver, whereas the Welby Station
is in a very rural location.
II-8
-------
AIR QUALITY
MONITORING STATIONS
LEGEND
1. CAMP
2. JEWISH HOSP.
3. OVERLAND
4. CARIH
5. ARVADA
6. WELBY
-------
100
90
80
70
60
50
40
30
20 -
10 -
CAMP
NUMBER OF DAYS IN 1974 STATIONS
RECORDED LEVELS EXCEEDING STANDARD
JEWISH
HOSP
V
URBAN
CARBON MONOXIDE
OVER-
LAND
CARIH
ARVADA
SUBURBAN
WELBY
RURAL
CO
<=
•so
I
GO
-------
Annually, the winter season is the worst for CO, This is because
the inversion heights are lower and the CO is trapped in more con-
centrated form. Figure II-C shows the annual trend in 8 hr. CO vio-
lations for 1974.
During an average day, CO concentrations tend to peak during the
traffic rush hours in the morning and afternoon. Figure II-D demon-
strates a typical "CO day" at the downtown CAMP station. Since CO
is directly emitted from car exhausts Cthe principal source of CO
in the Denver region is the automobile) concentrations are highest
along major streets and busy intersections. These areas of high CO
concentrations are often referred to as "hot spots."
Ozone is not directly emitted by sources, but is formed from
hydrocarbon and NOX emissions by the action of sunlight. Since time
is required for the ozone to form, it occurs in the highest concen-
trations down-wind from the sources of the hydrocarbons as shown in
Figure II-E.
About 70% of the hydrocarbon emissions in Denver come from motor
vehicles, and about 30% of the hydrocarbons come from stationary
sources like petroleum refineries, gas stations, and dry cleaners.
Unlike CO, Ozone because of the way it is formed tends to record
highest values in the suburbs. This occurs because during days when
wind speeds are low the hydrocarbons and oxides of nitrogen will have
formed Ozone about the time the pollutant cloud has drifted over the
suburbs and into rural areas. This trend is shown in Figure II-F. In
1974 every monitoring station had a significant number of days when
the ozone standard was exceeded.
Ozone tends to be a problem in the summer because larger quanti-
ties of ultra-violet radiation from more intense summertime cause more
ozone to be formed. Figure II-G shows this summertime peak in ozone.
This characteristic is in direct contrast with the annual distribution
of CO concentrations shown in Figure II-C.
Particulate matter is defined as any material, except water, that
exists in a finely divided form as a liquid or solid. Since Denver
lies in an arid section of Colorado, much of the particulate matter
is generated from unpaved roads, construction operations and natural
soil erosion.
Particulate levels in the Denver area also exceed the standards
regularly. Fourteen of the twenty-two existing particulate monitors
in Denver currently record violation of the ambiant annual particu-
late standard. Depending on the location, these levels vary from
slightly over the standard (74 mg/m3) to almost double the standard
in 1974.
11-11
-------
20
DAYS CARBON MONOXIDE
EXCEEDED STANDARD
30
GO
>-
•X.
CD
10 V-
1 f M A M
J J A
1974
S 0 N D
-------
CARBON MONOXIDE LEVELS
COMPARED WITH TRAFFIC VOLUME
CAMP STATION
12 PM
6 AM
NOON
12 PM
-------
OZONE FORMATION
HYDROCARBON
EMISSIONS
-------
NUMBER OF DAYS IN 1974 STATIONS
RECORDED LEVELS EXCEEDING STANDARD
100
90
OZONE
•er
en
80
70
60
50
40
30
20
10
CAMP
JEWISH
HOSP.
OVER
LAND
CARIH
ARVADA
URBAN
SUBURBAN
WEIBY
RURAL
-------
10
DAYS OZONE
EXCEEDED STANDARD
JFMAMJ JASON
MONTHS
CD
I
CO
-------
The Denver region has one nitrogen dioxide monitoring station
which is located in the central downtown area where NO sources are
the densest. Even with all the photochemical acitivity frequently
experienced during the summer months, no violation of the Federal
annual average N0? concentration (0.05 ppm) was reported in the
Denver metropolitan area. Since NO- is formed from NO emissions in
the same photochemical process that forms Ozone, exceedances of the
N0£ standard may exist in the suburbs of Denver where presently no
NO monitor exists.
Table II-B summarizes the exceedances of the CO and Ozone standards
for 1974 and 1975. 1974 data was used for the above discussion,
however, 1975 data is similar. The frequency and magnitude of
violations decreased somewhat in 1975, however, average wind speed
also decreased. The decreases in air pollution are not thought to
be caused by any reduction in emissions between 1974 and 1975.
Spring and summer temperature increases generally accelerate the
biological processes used in some wastewater treatment facilities which
can intensify any potential odor problems. The same inversion and low
wind conditions trapping smog over the region also prevent adequate
dispersal and dilution of odors from point sources.
Pollutant Emissions in Denver—
For the purposes of evaluating and modeling the present and future
air quality in the Denver metropolitan area, a number of emissions
inventories of present and estimated future emissions of various air
pollutants including carbon monoxide, particulates, oxides of nitrogen
and hydrocarbons have been developed. These inventories were
compiled primarily by the staff members of the Air Pollution Control
Division of the Colorado Department of Health and by the Colorado
Division of Highways. A discussion of current emissions is presented
next. Future emissions which were utilized to predict 1985 and 2000
air quality levels will be discussed in the Probable Impact chapter.
The air pollutant emissions that constitute the main problem in
the Denver Metropolitan Area at present are carbon monoxide,
particulates, reactive hydrocarbons (which react to form ozone) and
also the oxides of nitrogen. Automobile traffic accounts for a
major fraction of the pollutants emitted. All traffic accounts for
roughly 80 percent of the hydrocarbon emissions, 30 to 40 percent
of the nitrogen oxide emissions, and about 90 percent of the carbon
monoxide emissions. It is thought that while automobiles and other
vehicles do not directly contribute a high proportion of the particu-
late emissions in the Denver Metropolitan Area, street sanding opera-
tions, which are related to the operation of these vehicles, contribute
anywhere from 45 to 60 percent of the total particulate emissions.
Next to automobiles and other traffic point sources are the most
significant contributors to total emissions. Large point emissions
11-17
-------
Table II-B. MAXIMUM POLLUTION CONCENTRATIONS MEASURED
DURING 1974 AND 1975 IN DENVER
One-hour CO*
i— i
M
1
1 — i
00
Sample
CAMP
Nat.
Jewish
Arvada
CARIH
Overland
Welby
Days with vio-
lations, X
1974 1975
2 2
2 2
0
0
0
0
2nd max
PPM
1974
61
49
28
26
25
22
1975
46.1
43.1
23.5
27.3
22.5
27.5
Max
PPM
1974
70
59
32
27
30
24
1975
47.2
51.4
26.9
27.9
28.8
30.8
Eight-hour C0b
Days with vio-
lations, X
1974
29
17
8
10
4
6
1975
21
19
3
8
2
4
2nd max
PPM
1974
28.9
19.1
15.2
14.8
11.7
13.5
1975
22.3
23.1
14.0
21.9
12.0
16.6
Max
PPM
1974
30.3
19.7
17.0
IB. 6
14.6
16.3
1975
22.6
24.0
16.0
23.3
15.0
19.0
One-hour
Days with vio-
lations, %
1974
9
9
21
14
15
36
1975
5
4
22
17
13
18
03C
2nd max
PPM
1974
.180
.140
.170
.140
.165
.250
1975
.115
.108
.178
.135
.135
.177
Max
PPM
1974
.185
.155
.220
.155
.165
.375
1975
.132
.110
.197
.139
.139
.182
aOne-hour CO standard • 35 PPM
bEight-hour CO standard - 9 PPM
C0ne-hour 03 standard - .08 PPM
Source: JRPP Air Quality Assessment Statement, Colorado Division of Highways,
1 November 1976.
-------
alone account for as much as 50 percent of the total emissions of
the oxides of nitrogen. Table II-C gives the Denver emissions inven-
tory estimated for 1974.
Public Concern—
While the air pollution standards were developed out of concern
for public health and physical welfare, it is also important to con-
sider the public's feelings towards air pollution in allocating and
directing resources to help solve the problem. Information which was
gathered by six surveys conducted between 1969 and 1972 about public
attitudes towards Denver's air pollution problem is briefly presented
here. These six surveys were different in intent but do have common
elements which can be treated collectively. A more detailed review
and summarization of these public survey results is contained in
Reference 997- Information from these same six surveys on the
public attitude in Denver towards air pollution control measures is
presented briefly in the section on Mitigation Measures.
It appears to the public that air pollution is a serious problem.
In three surveys, over 90 percent of the respondents indicated that
air pollution was serious in some degree with 40 to 50 percent indi-
cating it was "very serious" or extremely serious." This latter range
is comparable to other findings from Buffalo, New York where air po-
llution was considered a serious problem by 40 to 60 percent of the
total sample. Two of the Denver surveys ranked air pollution as the
number one problem from a list of neighborhood or environmental prob-
lems. However, in the Buffalo survey air pollution was ranked be-
hind juvenile delinquency and unemployment, and about the same as
alcoholism. In another Denver survey air pollution was not ranked
first among a group of problems but, ranked third behind help for
schools and help for children on drugs.
Two of the Denver public surveys indicated concern about air
pollution in terms of reducing existing pollutant levels. In one
survey, 91 percent of the respondents considered reducing pollutant
levels important in metropolitan Denver. In another survey 81 per-
cent of the respondents indicated that either a "moderate" (27 percent)
or "great" (54 percent) increase was needed in efforts to control
air pollution.
Information about the perceived causes of air pollution is also
available from the Denver surveys. In one survey 56 percent indica-
ted their belief that "motor vehicles" were the worst cause of
air pollution while in another survey 72 percent thought "automobiles"
were the major source. These results indicate that the Denver public
perceives the causes of the problem with some accuracy as motor
vehicles are the major source of both carbon monoxide and hydrocarbons
(which lead to ozone formation) in Denver and significant contributors
to other pollutants.
11-19
-------
Table II-C 1974 DENVER EMISSIONS INVENTORY
Source
Carbon monoxide3
Automotive
Space heat
Point sources
Total
Hydrocarbons'3
Automotive
Space heat
Oil paint
Gas stations
Cleaners
Incinerators
Point sources
Airports
Total
Particulate
Space heat
Automotive
Airports
Construction
S treed sanding
Point sources
Total
N02
Space heat
Small points
Automotive
Airports
Point sources
Total
Emissions,
tons
(per day)
2,925.0
2.9
167.6
3,095.5
(per day)
199.18
0.48
2.08
11.67
4.94
0.11
13.14
5.92
237.52
(per year)
511
4,213
63
8,730
15,857
5,981
35,355
(per year)
5,348
87
31,646
1,552
33,773
72,406
Contributions,
%
94.5
0.1
5.4
100.0
83.9
0.2
0.9
4.9
2.1
0.0
5.5
2.5
100.0
1.4
11.9
0.0
24.7
44.9
16.7
99.6
7.4
0.0
43.7
2.1
46.6
99.8
Q
Based on winter emissions distributions.
Based on summer emissions distributions.
11-20
-------
Geology
The Denver area is divided into two distinct bedrock regions, both
of which dip to the east. The slightly dipping strata of the plains
is separated by a north-northwest, south-southwest trending zone of
sharp, almost vertical folds from the steeply dipping strata of the
Front Range. The locations of unique and significant geological
structures and formations are shown on Map E and described in Appendix
Table A-2.
The most important potential geologic problem in the Denver area
is the shrink-swell characteristics of bartonitic clays found in the
Denver-Arapahoe and other formations underlying most of the clay-
derived soils in the area. Shrink-swell potential, which can place
severe restrictions on urban development because of slippage and
differential settling risks, is greatest in the foothills west of
Denver where special site is needed. This potential is moderate-to-
low elsewhere in the region. Other, less widespread geologic hazards
include landslides in the western foothills having slopes greater than
25 percent and soils supported by clay substrata; subsidence and slope
instability in mining areas found scattered on the north, west, and
south peripheries of the metropolitan area; and faults (see Map C)
representing a very low potential for seismic activity in the region.
Soils
Soils in the study area have been surveyed by the U.S. Soil
Conservation Service (SCS) in recent years. Final survey reports have
been published for Adams and Arapahoe Counties (Reference 701 and 702),
while the results of the other county soil surveys for the study area
have yet to be published.
Because considerations of the agricultural capabilities of the
regional soils will be discussed at length under "Land Use Management
Considerations, Agricultural Lands" this discussion will address only
general soil-related problems. The major problem of most soils in
the region is shrink-swell characteristics as discussed above and in
Appendix A. The other significant regional soils problem is aeolian,
i.e., wind erosion. Where dryland farming is practical, wind erosion
causes losses of valuable topsoil during severe windstorm episodes.
This problem is especially critical in the dryland farming areas of
Adams and Arapahoe Counties.
Hydrology
The principal hydrologic feature is the South Platte River and
its tributaries. The South Platte River and the tributaries of Bear
Creek, Clear Creek, Boulder Creek and Coal Creek have their headwaters
in the mountains to the west (see Map E). They are snowmelt streams
whose annual variation of flow are directly related to the snow pack
11-21
-------
accumulated during the previous winter. Approximately 75 percent of
the annual flow occurs during the spring and early part of the summer,
peaking in May or June. The remaining 25 percent of the flow occurs
during the fall and winter months, with the low flow in January or
February. The other major tributaries including Cherry Creek, Sand
Creek, Big Dry Creek and Plum Creek rise on the plains east of the
mountains. Flow of these streams comes principally from precipitation.
All streams in the study area respond vigorously to frontal and
thunderstorm rainfall events.
The natural flow of the South Platte River is insufficient to
meet the total demand of municipal, industrial, and agricultural users,
which has lead to an elaborate regulation and distribution system
consisting of diversions for irrigation, transmoutain diversions to
augment basin supplies and numerous reservoirs for irrigation and
flood control (see Figure II-H). This system of water use, reuse
and subsequent use radically alters the natural flow characteristics
of many streams. Flows in Cherry Creek below Cherry Creek dam are
sometimes comprised entirely of urban runoff. At times, the flow in
Clear Creek below Golden is primarily from sewage treatment plant
effluent and at other times it is dry due to irrgation diversions.
Sand Creek is frequently an intermittent stream with periods of no
flow. Normal flows in Big Dry Creek are primarily irrigation and
irrigation return flows in addition to urban runoff.
Past urbanization has severely constricted some of the drainage
ways to the point where structural measures are necessary to safely
pass a 100 year flood without substantial property damage. Several
structural flood control projects have been undertaken in the area to
at least the master planning design stage. They include Chatfield
Dam, Cherry Creek Dam, and Bear Creek Lake Dam (under construction),
and channel improvements for Sanderson Gulch which is designed for
the 10 year flood event. Regulations are in effect in the counties
of Jefferson and Boulder, and the cities of Arvada, Lakewood, Boulder,
and Thornton to limit the peak rate of runoff from urbanizing lands
to the historic peak rate. The basin or regionwide effect of
requiring individual developments to provide detention to meet
historic peak runoff requirements is yet to be determined for the study
area. The aggregate effect may be higher peak rates of runoff for
downstream reaches because detained hydrographs from individual sub-
basins are long and flat and are more likely to become additive.
Present major drainage planning is based on future basin development
and considers that detention requirements will not be effective (see
Map G).
Water Supply
The largest municipal water supplier is the Denver Water Department
which provides the City and County of Denver plus a number of suburban
cities, special districts and other agencies with approximately
11-22
-------
-GREEN MTN. RES
WILLIAMS
WILLIAMS FORK RIVER
\^*
VASQUEZ TUNNEL
CONTINENTAL DIVIDE
GROSS RESERVOIR
BRAND
JUNCTION
FORK
RESERVOIR
IOFFAT TUMNEL
EAGLE-
COLORADO
RESERVOIR
- "ALSTON RESERVOIR
GUMLICK TUNNEL
-7
PLANT
DILLON
RESERVOIR
KASSLER
TREATMENT
PLANT
AREA
ENLARGED
(/TWO FORKS
•;' RESERVOIR
CONTINENTAL DIVIDE
CHEESMlk
RESERVOIR
PLATTE CANYON RESERVOIR
STRONTIA SPRINGS RESERVOIR
FOOTHILLS
,/ii--^;.-\ TREATMENT
CASTLE ROCK
ANTERO RESERVOIR
ELEVEN MILE
RESERVOIR
COLORADO SPRINGS
EXISTING
PROPOSED
SOURCE: RTD
WATER SUPPLY SYSTEM
DENVER WATER DEPARTMENT
-------
two-thirds of the municipal raw water used in the region. The next
largest independent system is Aurora's which supplies over six per-
cent of the region's annual raw water demand. Thirty-three percent
of the raw water utilized for municipal purposes in the region is
transmountain water imported from the headwaters of the Colorado
River west of the Continental Divide by the cities of Denver, Aurora,
Englewood, and Boulder. Projections of future water supplies and
demands by the Denver Water Board indicate that demand for will ex-
ceed dry year supplies before 1980 and average year supplies by 1988.
Figure II-I graphically shows dry year and average year water sup-
plies relative to two rates of demand based on two population projec-
tions and the effect of water conservation. Under existing use con-
ditions, planning proposals, and water rights laws, new water sup-
plies would likely be imported rather than developed in the Denver
basin where existing supplies are near or at maximum utilization.
The year 2000 projection of 3.214 million was the one used by the
Denver Water Board. The year 2000 projection of 2.35 million is
the one developed by DRCOG and is used for water quality planning.
There are two groundwater systems in the Denver area. The
first (see Map C) is the shallow groundwater system of aquifers
underwater table conditions found in the floodplains and terraces
of the South Platte River basin, in the dune sand deposits that
occur in the vicinity of the Rocky Mountain Arsenal, and in the
alluvial fan remnants that occur adjacent to the front range moun-
tains . Recharge to these aquifers occurs in areas where deposits
are exposed to the land surface. Further onto the plains area,
streams receive groundwater discharges from shallow groundwater
aquifers which accounts for much of the flow in the South Platte
basin during the latter part of the summer. These shallow ground-
water aquifers are also sources for domestic water supply. The
second system is the deep groundwater system consisting of Dawson,
Denver, Arapahoe Formations and the Laramie-Fox Hills sands con-
taining water under pressure at depths ranging from 500 to 3,000
ft. beneath the Denver area. Recharge generally occurs through-
out the sourthwestern quarters of the study area and discharge in
the northwestern quarter. These aquifers are exposed at the sur-
face in an oval-shaped structure where streams cross the exposed
sandstones. Recharge also occurs by vertical percolation of ground-
water through overlying beds of shale in the Denver and Castle Rock
areas. North of Dawson the deep aquifers discharge groundwater
vertically to the land surface.
Water Quality
The following discussions of current water quality in the
Denver region are based in large part on information developed
11-24
-------
FIGURE ll-l
1 ,000
800
o
C3
600
400
200
3.214 MIL. POP
215 GAL/CAP.
2.35 MIL. POP. 215 GAL/CAP
OR 3.214 MIL. POP. 164 GAL/CAP.
2.35 MIL. POP
70 GAL/CAP
2.35 MIL. POP. 150 GAL/CAP.
1970
1980
1990
2000
2010
YEAR
NOTE: POPULATION FIGURES ARE
FOR THE YEAR 2000.
PRIMARY AREA WATER SUPPLY AND DEMAND
(DATE FROM 1975 METRO WATER STUDY)
11-25
-------
by DRCOG and its consultants to support the preparation of the
Denver Clean Water Program (CWP). This program is frequently or
commonly termed the 208 Plan because it is required by Section
208 of the Water Pollution Control Act Amendments of 1972.
Detailed technical information that supports the discussion
presented here can be found in Appendix A and on Map E.
A number of parameters (physical, chemical, and biological
characteristics) are used to indicate water quality. These char-
acteristics are important because they either directly affect
people and wildlife or indirectly interact to cause effects. For
example, certain amounts of dissolved oxygen (DO) in the water
are necessary to support fish life and other desirable organisms.
Water temperature (T) affects the amount of dissolved oxygen water
can contain. Biological oxygen demand (BOD) refers to the amount
of organic material which is available as food for various or-
ganisms. When a large amount of food is available, the number
of organisms increase and the amount of oxygen in the water is
reduced. The term BOD,- is commonly used to indicate the BOD over
a five day period. Total dissolved solids (TDS) are in the form
of salts. High TDS in water for agriculture limits crop produc-
tivity and can cause salts to build up in soils and permanently
degrade agricultural soils . High TDS makes water disagreeable
to taste and can cause effects such as diarrhea. It also limits
the use of water by industry in manufacturing processes. Fecal
coliforms and streptocci (colistrep) are bacteria naturally oc-
curring in the intestines of humans and warm-blooded animals.
The presence of these bacteria are used as indicators of fecal
contamination of water, and thus the possible presence of di-
sease causing bacteria. Ammonia (NH-) is toxic to fish. Nitro-
gen and phosphorous compounds (NO,,, PO,) supply nutrients to.
small water-borne plantlike organisms. Algal blooms may occur
and cause unpleasant odors and unsightliness. Also, when these
organisms die and decay, they represent a BOD.
Desired Water Quality—
During the 208 Planning Study, various water uses were
considered and evaluated for the study area. Four broad areas
of desirable uses were identified: agriculture (irrigation
and livestock watering), recreation (primary and secondary con-
tact) maintenance of aquatic life (cold and warm water fisheries
and stream or lake aesthetics) and domestic raw water supply.
Stream classifications and the requisite stream quality
parameter values for these uses are indicated in Table II-D.
11-26
-------
Table II-D. STREAM CLASSIFICATIONS AND ALLOWABLE LIMITS FOR SPECIFIC WATER USES
H
M
I
Streao
classi-
fication
B2
Bl
AZ
A;
Tempera- Dissolved
ture, oxygen,
Uses °C BE /I
Aesthetics (stream), 8 to 30 5
wildlife and live-
stock watering, urban
irrigation, secondary
warm water fishery
Sane as above (Bi ) 5 to 15 6
f ishery
Aesthetics (stream S to 30 5
or like), wildlife
and livestock water-
ing, urban irriga-
tion, primary contact
recreation, domestic
potable water (raw
supply), warm water
fishery, plus all
B? uses
Same as above (A2 ) 5 to 15 6
except as cold water
fishery, plus all B^
uses
Water aualitv
Total
BODs , dissolved
mg/1 solids, mg/1
1,000
to
3,000
1,000
3,000
500
500
parameters /limits
Fecal Fecal
conforms, streptococci,
MPN/100 ml KPN/100 ml
200 20
to
1,000
200 20
1,000
200 20
200 20
NHj-N, N03-N, Total N, POi,-P,
ig/1 mg/1 mg/1 mg/1
0.3 10 10 0.05
to
4
0.6 10 10 0.05
5
0.3 10 10 C.025
to to
0.5 0.1
0.5 10 10 0.02f
to to
0.8 0.1
Source: References 209 and 228
-------
The values shown are those used in the 208 Study and will be
utilized in this report both as being consistent with the avail-
able data base and as representing the latest available informa-
tion. Table II-E indicates the classification by reach of the
streams within the study area.
Table II-F presents the historical and present uses, pre-
cent State stream classification; and the latest suggested use
potential and classification of the major streams in the study
area. It should be recognized that the use potential represents
goals for the study area consistent with the national goals of
"fishable and swimmable waters" by 1983 and "zero" discharge of
pollutants by 1985 as stated in the Federal Water Pollution Con-
trol Act Amendments of 1972.
Existing Water Quality—
The following subsections present the existing water quality
in the study area by basin. Table II-G is a list of the waste-
water treatment facilities that were investigated for their impact
upon stream water quality. Discussions are based on stream data
obtained during calendar year 1972.
Data for 1972 was used largely because this was the year
picked by DRCOG for 208 planning as most representative of flow
conditions for the last several years and for which water quality
data were available.
The data used to characterize water quality in 1972 is sum-
marized in Table II-H . This data is compared with the recommended
levels shown in Table II-D for stream classifications shown in Table
II-E, to evaluate water quality in 1972.
Basin Water Quality Trends/South Platte— The following discus-
sions are based primarily on average levels for various water
quality parameters. Effects of runoff events will be discussed
after each water quality parameter is examined.
Water temperature, in addition to following normal season-
al trends, generally increases as flow proceeds through the ur-
banized area of the basin. Temperatures are within limits for
the water uses designated for the various streams or portions
of streams except for Bear Creek above Morrison, and the
South Platte above Littleton. Temperature limits are sometimes
exceeded during late summer.
11-28
-------
Table II-E. CLASSIFICATION BY STREAM AND REACH
Stream
Use
class
Reach
South Platte
South Platte
Sloans Lake
Bear Creek
Bear Creek
Cherry Creek Reservoir
Cherry Creek
Cherry Creek
Clear Creek
Clear Creek
Coal Creek
Coal Creek
South Boulder Creek
Source to Exposition Avenue
Exposition Avenue to Nebraska
A2 Inlet to outlet
Source to Morrison
Morrison to South Platte
Inlet to outlet
Source to reservoir
Reservoir to South Platte
Source to Farmers Highline Canal
Farmers Highline Canal to South Platte
Source to Highway 93
Highway 93 to mouth
Source to Highway 93
South Boulder Creek 62 Highway 93 to mouth
Boulder Creek
Boulder Creek
Sand Creek
Big Dry Creek
Source to Highway 119
Highway 119 to mouth
62* Source to South Platte
Eg* Source to South Platte
*Assumed for 208 study; not State of Colorado classification.
Source: Reference 228
11-29
-------
Table II-F. WATER QUALITY ATTAINABILITY/USE POTENTIAL
208 Basin
Historical and present use Present state classification
Use poteatial
Use classification
Upper Souch Platte
I
CO
o
South Metro
Lover South Platte
through Lakewood
Basin
Lower South Platte
through Clear Creek
Basin
Lower South Platte
below 104th Avenue
Cherry Creek above
reservoir
Natural trout stream formerly
Cold-water put-and-take fish-
ery at present to Chatfield
Reservoir
Swimming, rafting during
high flows
Natural trout stream form-
erly
Only rough fish in flowing
waters or pooled areas
Soir.e waterfowl use and some
boating
Only rough fish in flowing
waters/or pooled areas
Some waterfowl
Only rough fish in flowing
waters or pooled areas
Boating during high flows
Rough fish
Rafting in Highline Canal
during high flows
Cold-water fishery
BI Cold-water fishery
(to Exposition Avenue)
82 Warm-water fishery
(from Exposition Ave-
nue)
82 Warm-water fishery
(from Exposition Ave-
nue)
82 Warm-water fishery
Unclassified (A2 res-
ervoir)
Natural cold-water fishery
with suitable substrate and
flow conditions
Swimming, rafting
Rafting, boating
Cold-water fishery, put-
and-take
Boating
Warm-water fishery
Boating
Warm-water fishery
Warm-water fishery with
increased flows and im-
proved quality
Boating, rafting
Warm-water fishery
Secondary-contact recreation
March - August
Cold-water fishery
Secondary-contact recreation
March - August
Cold-water fishery
Secondary-contact recreation
March - August
Warm-water fishery below Expo-
sition Avenue March - Jur.e
Agricultural/industrial use
remaining months
Secondary-contact recreation
March - August
Warm-water fishery below Expo-
sition Avenue March - June
Agricultural/industrial use
remaining months
Secondary-contact recreation
March - August
Warm-water fishery March - June
Agricultural/industrial use re-
maining months
Secondary-contact recreation
March - August
-------
Table II-F. (continued) WATER QUALITY ATTAINABILITY/USE POTENTIAL
206 Easin
and present u.se Present statc classification
Use potential
Use classification
Cherry Creek below
reservoir
Sand Creek
Bear Creek through
Morrison
Sear Creek below
Morrison
Clear Creek
Golden
Clear Creek below
Golden
Rough fish and some warm-
water fish when flows con-
sistent
Boating in downstream areas
Rough fish in pooled areas
aost of the year
No recreation
Natural trout fishery to
Morrison formerly
Put-and-take fishery at pre-
sent
Some put-and-take fishery
at present
Rafting, boating downstream
from Morrison
Natural cold-water fishery
formerly
Natural cold-water fishery
to Idaho Springs
Fish populations precluded
from Idaho Springs to Gold-
en from low pH values, heavy
metals
Sorse trout and downstream
scr.e warm-water fish
species
Boating, rafting downstream
of Golden
Unclassified
Unclassified
BI Cold-water fish-
ery (to Morrison)
82 Warm-water fish-
ery (from Morrison)
BI Cold-water fish-
ery (to Highline
Canal)
82 Warm-water fisher-
ies (Highlins Canal
downstream)
Potential for secondary-
contact recreation in down-
stream areas
Warm-water fishery in. down-
stream areas, upstream with
flow releases
Boating
Recreational potential dar-
ing high flews
No fishery potential, only
rough fish
No recreation potential in
upstream area
Natural cold-water fishery
potential
Recreation potential for
rafting, boating
Potential for cold-water
fishery with releases from
Mr. Carbon Reservoir
Natural cold-water fishery
Co Golden
Rafting, boating
Warm-water fishery down-
stream of Golden
Secondary-contact recreation
in downstream segments March
August
Warm-water fishery March -
June upstream, entire year
downstream
Agricultural/industrial use
remaining months
Secor.dai~y- con tact recreation
March - August
Agricultural/industrial use
remaining months
Cold-water fishery
Secondary-contact recreation
March - August
Cold-water fishery March -
June
Agricultural/industrial use
remaining months
Cold-water fishery
Secondary-contact recreation
March - August
Warm-water fishery March - June
Agricultural/industrial use re-
maining months
-------
Table II-F. (continued) WATER QUALITY ATTAINABILITY/USE POTENTIAL
208 Basin
Historical and present use Present state classification
Use potential
Use classification
I
LO
N>
Big Pry Creek
upjtrean of Stand-
ley Reservoir
Big Dry Creek below
Standley
Coal Creek to inter-
section with Route
93
Coal Creek Route 91
to South Platte
Boulder Creek source
to Route 119
Boulder Creek Route
119 to 93
Put-and-take cold-water
fishery upstream of
Standley Reservoir
Rough fish and warm-water
fishery
Natural cold-water fish-
ery upstream formerly
PuC-and-take at present
Rough fish and warm-water
fishery
Natural cold-water fish-
ery
Cold-water'put-and-take
fishery
Rafting, swimming
Unclassified
Unclassified
Cold-water fishery
B2 Warm-water fishery
AI Domestic use, pri-
mary /secondary- contact
recreation, fisheries
BI Cold-water fishery
Cold-water fishery
Warm-water fishery with
sufficient flows
Cold-water fishery
Warm-water fishery
Domestic use, recrea-
tion
Cold-water fishery
Primary-contact recrea-
tion
Cold-water fishery with
reservoir releases
Cold-water fishery
Warm-water fishery March -
June
Agricultural/industrial use
remaining months
Cold-water fishery March -
June
Agricultural/industrial use
remaining months
Warm-water fishery March -
June
Agricultural/industrial use
remaining months
Domestic use, recreation
Cold-water fishery
Primary-contact recreation
Cold-water fishery
Boulder Creek Route
93 to St. Vrain Creek
Cold-water put-and-take
fishery and warm-water
fishery
62 Warm-water fishery
Cold-water fishery with
flows, otherwise warm-
water fishery
Cold-water fishery March -
June
Warm-water fishery June -
February
Agricultural/industrial use
regaining months
Mote: Historical snd pregenc usas were obtained through existing literature sources and from interviews RPA conducted with state and local experts in
fisheries and water quality management and with DRCOG representatives during the week of December 6-10 in the Denver area. State classifica-
tions are those made effective June 19, 1974. Use potential is a concensus of opinion of the experts interviewed for this analysis and RPA s
professional judgment as to the highest and best uses for these stream segments; use potential responds to the Colorado State Hater Quality
Control Commission's desire to assign a stream classification for the highest and best use to which a stream segment could be put on the basin
of past and present uses and/or natural conditions. Use potential does not consider the technological capability, cost, or socio-economic im-
pact of implementing such a classification. The use classification is presented as RPA1s recommendation for stream classification to meet
permits for Denver area streams. Those recommendations would be enforced by the Water Quality Commission as exception to the permanent stream
segment classifications.
Source: Reference 259
-------
Table II-G. WASTEWATER TREATMENT FACILITIES INVESTIGATED FOR THEIR
IMPACT ON EXISTING WATER QUALITY
i
OJ
OJ
Plant
Morrison
Glendale
Aurora
Ficzsinons
Coors
Wheatridge
Clear Creek Valley
Arvada
Crestview
Littleton
Englewood
South Lakewood
Metro Denver #1
South Adams County
Brootnf ield
Westminster
Erie
Lafayette
Louisville
Boulder White Rocks
Type
Activated sludge
rotot aeration
Activated sludge
Activated sludge
Trickling filter
Activated sludge
Trickling filter
Activated sludge
Trickling filter
Trickling filter
Trickling filter
activated sludge
Trickling filter
Activated sludge
Activated sludge
Trickling filter
Trickling filter
Activated sludge
Lagoon
Trickling filter
Activated sludge
aerated lagoon
Trickling filter
Primary
0.07
1.0
1.5
0.9
4.0
2.5
2.1
0.7
1.0
7.6
12.0
1.3
28.0
2.5
1.6
1.0
0.3
0.7
15.6
Capacity, mgd
Secondary
0.07
1.0
1.5
0.9
9.0
2.5
2.1
0.7
1.0
7.6/1.5
12.0
1.3
98.0
2.5
1.6
1.0
2.57 acres
0.3
0.7
15.6
Receiving Stream
Bear Creek
Cherry Creek
Sand Creek
Tollgate Creek
Clear Creek
Clear Creek
Clear Creek
Clear Creek
Clear Creek
South Platte
South Platte
South Platte
South Platte
South Platte
Big Dry Creek
Big Dry Creek
Coal Creek
Coal Creek
Coal Creek
Boulder Creek
-------
Table II-H.
EXISTING WATER QUALITY
(1972)
i
U)
Location
Winter
Bear Creek at Morrison
Beark Creek at mouth
Cherry Creek at Franktown
Cherry Creek at south
Sand Creek at loouth
Clear Creek at Golden
Clear Creek at mouth
South Platte at Blakeland
South Flatte at 38th Ave.
South Platte at Henderson
Spring
Bear Creek at Morrison
Bear Creek at mouth
Cherry Creeic at Franktown
Cherry Creek at mouth
Sini Creek Et mouth
Clear Creek at Golden
Clear Creek at mouth
South Platte at Blakeland
South Platte at 38th Ave.
South Platte at Henderson
State-
assigned
classifi-
cation
BI
B2
A2
B2
B2
B!
B2
BI
B2
B2
BI
B2
A2
B2
B2
BI
B2
BI
B2
B2
Tempera-
ture ,
Avg
6
10
2
8
9
4
8
7
8
8
10
20
10
20
20
10
20
15
17
18
Psak
12
17
4
18
15
10
20
12
15
16
14
25
16
25
25
13
25
18
24
23
Dissolved
oxygen,
Avg
12
11
13
10
12
13
11
9.5
10.5
9.5
10
9.5
10
8.5
10
8
8.5
7
8.5
8.3
Peak
15
12
14
12
-
15
12
10
12
11
11
11
11
9.8
11
8
11
8
10
9
Total
dissolved
solids, rct;/l
Avg
90
200
250
4SO
900
200
400
250
500
700
85
220
75
650
1.500
275
400
250
600
700
Peak
95
3,800
-
6,800
4,000
500
4,000
-
4,500
4,000
100
3,000
150
4,750
3,600
SCO
600
-
1.000
1,000
BOD,a
ir,g/l
Avg Peak
3
4
2
3
9
2
18
5
14
30
3
3
1.
3
10
2.
8
5
10
16
4
42
-
81
43
5
50
-
17
33
4
32
3 2
61
3S
5 5
15
-
17
20
Ammonia,
si^/l
Avg
0.13
0.2
0.01
1.0
5
0.23
4
0.01
3
10
0.13
0.2
0.02
0.6
5
0.23
1.5
0.01
1.5
8
Peak
1.8
0.05
3.5
7
-
11 '
-
3.8
13
-
0.7
-
2.7
6
-
7.3
-
3.5
15
Nitrate,
ir.R/i
Avg
0.31
1.0
0.11
3.0
3
0.4
2.5
0.03
1.5
1.8
0.31
1.5
0.16
2
3
0.4
2
0.03
1.5
1.8
Peak
6
0.15
5
4
-
4
-
1.8
5
-
4.5
0.18
4.5
5.2
-
2.8
-
2.8
4
Phosphate,
Avg
0.23
0.3
0.01
4
3.5
0.2
3.2
0.05
2
5
0.23
0.3
0.03
2.5
2.5
0.2
1.7
0.05
1
3
Peak
2
-
7
4.5
-
5
-
4.5
6.5
-
2.3
0.06
5.8
5
-
3.4
-
3.5
6.5
Fecal
coliforms,
MPM/100 ml
Avg
200
300
-
650
2,500
204
800
30
600
1,000
400
300
-
800
2,500
400
800
15
600
1,000
Peak
15,000
-
26,000
19,000
600
25,000
35
17.000
16,000
1,500
15,000
-
6,000
14,500
600
10,000
40
20,500
S.OOO
i- ecal
streptococci,
MP:;/IOO n-.i
Avf,
300
700
-
1,800
4,000
300
300
40
20,000
2,500
300
700
-
1,000
4,000
200
300
32
20,000
2,500
peak
154,000
-
204,000
123,000
400
200,000
45
130,000
125,000
1,000
121,000
-
22,000
84,000
400
90.000
40
100,000
65,000
-------
Table II-H. (Continued) EXISTING WATER QUALITY
(1977)
M
M
I
OJ
Ul
State ToEpera-
assigned ture,
clissifi- °C
Location cation
Su-jier/Fall
Bear Creek ^t Morrison
Bear Creek at mouth
Cherry Creek at Franktown
Cherry Creek at mouth
Sand Creek at mouth
Clear Creek at Golden
Clear Creek at nouth
South Platte et Blakeland
South Platte at 3Sth Ave.
South Platte at Henderson
Bi
B2
A2
B2
S2
BI
B2
Bl
B2
B2
Avp,
14
21
15
20
20
13
22
16
20
20
Peak
20
28
20
26
26
20
28
21
26
27
Dissolved
oxygen,
TT1£/1
Avg
10
9
10
8.5
9
10
9
6.5
8
8
Teak
12
10.2
11
9.8
10
12
10.5
8
9.1
9.2
Total
dissolved
solids, m^/1
Avg
85
250
230
725
1,200
175
400
250
650
700
Peak
95
3,600
250
6,600
3,300
200
600
-
4,600
2,000
BOD,a
Avg Peak
2.5
2
2.7
3
6
2
8
5
10
10.2
3
41
3
75
35
5
13
-
16
16
Airmonia,
r,R/l
Avg
0.
0.
0.
0.
3
0.
1.
0.
1.
7.
13
15
07
0
23
2
01
8
5
Peak
1.
0.
4.
6.
-
o
-
3.
12.
8
10
3
5
5
6
5
Nitrate,
ns/1
Avg
0.
1.
0.
2
3.
0.
2
0.
1.
2
31
0
18
1
5
4
03
8
Peak
4.3
0.20
5.5
4.5
-
2.3
-
4
3.5
Phosphate,
rag/I
Avg
0.23
0.3
0.04
2.5
3.5
0.2
1.4
0.05
1.5
4
Peak
1.7
0.05
6.2
8.5
-
1.5
-
4
6
Fecal
colilornis,
MPN/iOO cl
Avg
200
300
-
800
2,500
204
800
20
600
1,000
18
26
12
10
16
10
Peak
,000
-
, 000
,500
400
,000
30
,000
,000
Fecal
streptococci,
Mi' i: /I GO Til
Avg
300
700
-
1,000
4,000
300
300
34
20,000
2,500
Peak
140,
1S2,
56.
90,
130,
75,
000
-
000
000
330
000
40
000
000
oxygen demand.
-------
Dissolved oxygen (DO), also follows expected seasonal trends
with DO levels decreasing from winter levels during the course of
the year until fall when water temperatures begin to decrease, and
DO levels begin to rise. Dissolved oxygen levels decrease as water
flows through the Denver area. Dissolved oxygen levels consistent-
ly meet recommended limits for the various water uses.
Total Dissolved Solids (IDS) show weak seasonal trends, but
seem most influenced by flow through the urban area. IDS levels
for tributaries to the South Platte generally increase by a factor
of two as streams progress through the urban area. With the ex-
ception of Sand Creek, levels for TDS are at or below limits recom-
mended for specific water uses. The high RDS levels in Sand Creek
are due in large measure to the nature of the creek bed, and the
gravel mining which occurs on upstream portions of the stream.
Five day Biological Oxygen Demand (BOD,-) levels generally are
fairly constant throughout the year in the upstream portions of
basin streams. The same is also true at the mouth of Cherry Creek.
BODr levels where Bear and Clear Creeks enter the Platte and on
the Platte below Littleton decrease from winter highs to lowest
levels in the summer and fall. Only Sand Creek at the mouth showed
peak levels in the spring instead of winter. These trends appear
to indicate a greater influence from point sources during winter-
time low natural stream flows. The highest BOD,- levels in the South
Platte occur at Henderson, and the highest levels in tributaries
occur at the mouths of the Clear and Sand Creeks.
The downstream portions of Clear, Sand, and Cherry Creeks
as well as the South Platte below Littleton have ammonia (NH_)
concentrations (in conjunction with pH and temperature) which
are on the average at potentially toxic levels throughout the
year. The highest levels, 10 mg/1, occur in the South Platte at
Henderson during the winter. Highest ammonia levels generally
occur in winter for the streams mentioned. Ammonia levels in
the headwaters are at acceptable levels.
Nitrate levels throughout the South Platte basin are within
acceptable levels. Table II-H shows that the highest levels
occur in Sand Creek, Cherry Creek, and Clear Creek where these
creeks flow into the South Platte. These levels vary between
2.0-3.5 mg/1, which is singificantly below the recommended limit
of 10 mg/1 for Nitrate. However, recommended levels for total
nitrogen are exceeded in the South Platte at Henderson.
11-36
-------
Levels of phosphate exceed recommended levels throughout
the basin during the year except for wintertime levels in Cherry
Creek above Cherry Creek Reservoir and the South Platte above
Littleton which is at the limit. Phosphate levels increase down-
stream from upstream. The upper portion of Cherry Creek above
the reservoir is the only headwater showing a variation in levels
through a year. Bear Creek at the mouth had constant levels of
phosphate, however, a seasonal trend is very pronounced for the
remainder of the tributaries where they flow into the South Platte
as well as for the South Platte itself. This trend begins with
high levels during the winter, with generally lower levels through-
out the remainder of the year until fall when levels begin to climb
to winter highs. Phosphate levels are highest in the South Platte
at Henderson where levels of 5.0 mg/1 occur. The recommended level
is 0.05 mg/1. The next highest levels occur in Cherry Creek at the
mouth, 2.5-4.0 mg/1, Sand Creek at the mouth, 2.5-3 mg/1, and
Clear Creek at the mouth, 1.4-3 mg/1.
Fecal coliform recommended limits are met year round only in
the South Platte above Littleton. They are equalled during summer,
fall, and winter in the headwaters of Bear and Clear Creeks, but
are exceeded during spring. No data exists for Cherry Cfe'ek "above
Cherry Creek Reservoir, but a similar trend is expected. The
higher levels in downstream portions of the basin are essentially
constant throughout the year. The highest levels in the basin
are found in Sand Creek at the mouth with 2500 MPN/100 ml.
Recommended limits for Fecal Streptocci (FS), 20 MPN/100ml,
are exceeded throughout the South Platte basin throughout the
year. The lowest levels, 32-40 MPN/100 ml, are found in the
South Platte above Littleton. FS levels are essentially constant
throughout the year except at the mouth of Cherry Creek where
winter levels are substantially above levels for the remainder
of the year. The highest levels in the South Platte basin occur
in the South Platte at 38th Avenue in Denver, approximately one
mile downstream of where Cherry Creek enters the South Platte.
These levels are constant. The next highest levels 4,000 MPN/
100 ml, are found in Sand Creek at the mouth. Very high levels
are also found in the South Platte at Henderson; 2,500 MPN/100 ml,
and at the mouth of Cherry Creek, 1,000-1,800 MPN/100ml.
The previous discussions were concerned with water quality
during average conditions. Table II-G also indicates peak
levels that occur during various seasons of the year. Data
indicates that these peaks occur during runoff events such as
snowmelt and/or rain in the region. A review of Table II-H
*MPN means Most Probable Number of organisms.
11-37
-------
indicates that peak levels during runoff events at times ex-
ceed recommended levels which are in some measure met during
average conditions for Total Dissolved Solids (IDS), and Am-
monia (NH~) .
The following discussion will be limited to these two para-
meters. Temperature and Dissolved Oxygen levels by themselves
are not generally a problem during runoff events, and peak levels
of Nitrate are still within limits. Levels for Phosphate, Fecal
coliform and Fecal streptococci generally exceed recommended levels
during average conditions. The levels of these pollutants in the
headwaters indicates a background level most probably caused by
non-point sources further upstream.
Levels of TDS exceed recommended levels during runoff events
throughout the year at the mouth of Bear, Cherry, and Sand Creeks and
in the South Platte below Littleotn. Levels are exceeded at the
mouth of Clear Creek during spring, summer, and fall. Few general
statements can be made about trends because such factors as localized
rain storms may have distorted the information given Table II-H. Two
observations can be made however. The highest peak levels of TDS oc-
curred in Cherry Creek. The reason for this is not known. This was
true for every season of the year. Also, peak TDS levels are gener-
ally highest during the winter at the mouth of the tributaries, and
downstream from Littleton in the South Platte. These winter peaks
correspond to small peaks in flow which infers that the wintertime
TDS peaks are associated with snowmelt runoff from streets treated
with salts.
Virtually no data exists for Ammonia peak levels at the headwaters
of the tributaries or for the South Platte above Littleton. The data
for the lower reaches indicates recommended levels are exceeded during
runoff events. No strong seasonal trends are apparent. The highest
peaks in Ammonia concentrations occurred in the South Platte at Hen-
derson with concentrations of from 12.5-15 mg/1.
Big Dry, Coal and Boulder Creek Basins—There are no significant ex-
isting data for these basins available for assessment of seasonal
variations in water quality, nor are there sizeable amount of data
for assessment of nonpoint or point-source water quality.
Water quality for Boulder Creek at its mouth (confluence with St.
Vrain Creek) indicated an arthmetic mean of samples taken 7-12 Septem-
ber 1971 for BOD5 of 2.8 mg/1, total dissolved solids of 955 mg/1, fecal
coliform of 1,080 MPN/100 ml and fecal streptococcus of 14,500 MPN/100 ml.
It hat also been noted that below the Boulder/White Rocks treat-
11-38
-------
ment plant chlorine and ammonia residuals preclude the migration
farther upstream of sensitive fish species; fecal coliform and fecal
streptococcus counts increase from upstream levels; and dissolved
oxygen falls to a range of 6 to 8 mg/1 from upstream levels of 9 to 12
mg/1. The headwaters of Boulder Creek were noted to have high levels
of dissolved oxygen and temperatures from November through March of 5°C.
It has also been noted that Phosphate levels are apparently higher than
suggested levels for stream aesthetics (0.06 mg/1).
Coal Creek, in the upper portion of its basin, has temperatures
and dissolved oxygen levels sufficient to support a put-and-take trout
fishery. The lower poriton's water quality was degraded in 1972 be-
cause of discharges from the Erie, Lafayette and Louisville municipal
treatment plants and the extraction of coals, and show levels of fecal
coliform and fecal streptococcus greater than 200 MPN/100 ml.
Water quality in the upper portion of Big Dry Creek Basin was
unaffected in 1972 by point sources of pollution and has been suitable
for use as a cold water fishery. It appears that levels of phosphate
and total nitrogen are lower than suggested levels for stream aesthetics.
In the lower portion, water quality is impacted by low releases from
Standley Reservoir and point-source inflows from the Westminster and
Broomfield municipal wastewater treatment plants. Coliform levels
periodically exceed suggested levels for urban irrigation, and secondary-
contact recreation.
Sources of Water Quality Problems—
This discussion will address the causes of water quality problems
identified in the two previous sections of this report. It is based
upon material previously referenced and consists of data generated dur-
ing DRCOG's 208 Water Quality Modeling and Planning activities. Table
II-I presents a summary of pollutant amount in each basin by major cate-
gories, i.e., point sources and non-point sources. The following dis-
cussions are organized by basin as appropriate.
General—The two indicators of pathogenic organisms, fecal coliforms and
streptococci, are a consistent problem throughout the South Platte
basin. Table II-I clearly shows that the overwhelming majority of these
organisms come from non-point sources. Point sources of fecal coliforms
constitute less than one percent of the total number, and point sources
of fecal streptococci constitute less than one-tenth of one percent.
Nitrates do not presently represent a water quality problem and
will not be discussed further. The highest levels are found in the
South Platte below 38th Avenue, 1.5-2.0 mg/1. These levels are signi-
ficantly below the recommended level of 10.0 mg/1. However, Nitrates
plus Ammonia levels at Henderson exceed total Nitrogen recommended levels
of 10 mg/1 in winter when total Nitrogen levels of 11.8 mg/1 occur.
11-39
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Table II-I.
COMPARISON OF ESTIMATED POINT AND NONPOINT SOURCE LOADING
IN THE SOUTH PLATTE AND MAJOR TRIBUTARIES
(pounds per day)
M
M
iBasin
Bear Creek
Cherry Creek
Sand Creek
Clear Creek
South Platte
South Metro
Kiddle
Lower
Totals
BOD5
CTS
SOS
2,500
5,500
4,120 4
2,600 4
8,500
4.2CO 36
28,328 46
?sb
18
65
103
,300
,900
485
,000
,411
NPS3
77,300
207,200
445,000
349,000
220,400
712,400
321,000
2,332,300
IDS ,
psb
410
5,770
9,700
68,300
78,600
10,600
667,600
840,930
NPS3
80
180
450
340
200
670
320
2,240
9
27
108
770
1,810
240
18,100
21,054
spsa
70
180
400
300
190
630
310
2,080
"*PSb
5
97
86
1,030
860
130
7,300
9,558
Fecal
NPSa
1,441,000
3,975,000
8,851.000
6,049,000
3,934,000
11,741,000
7,673,000
43,664,000
colif orn^.
PS"
37,850
50,720
36,600
72,000
83,300
15,100
22,800
318,370
Fecal strept
9,553,000
27,757,000
55,814,000
39,693,000
21,760,000
77,346.000
43,057,000
279,980,000
OCOC -L,
7,600
6,400
7,200
17,000
26,500
3,800
3,800
72,300
Ncte: a. Konpoint source loading are 1970 levels as given in Reference 215.
b. Point source loadings are estimated from yearly average effluent flows and quality for major municipal treatment plants as input to tne
Hydrocorop Model for 1972.
c. -Values are ir. units of 10^ per day.
d. Effluent levels estimated for Morrison eewage treatment plant.
-------
Bear Creek Basin—Aside from occasional high temperatures in the head-
waters and the aforementioned fecal coliform and streptococci problems,
Bear Creek has levels of Phosphates higher than recommended for current
goals for beneficial u.se. Table II-I data indicates that less than
seven percent of this pollutant comes from point sources. The pollu-
tion problems that do exist on Bear Creek are caused by non-point sources.
The data cited for this discussion do not include the effects of con-
struction of Bear Creek Lake Dam near Morrison which probably is in-
creasing suspended solids, TDS, and stream bed sediment loads.
Cherry Creek Basin—The water quality problems in this basin, other than
FC and FS, occur below Cherry Creek Reservoir and are associated with
high year round Phosphate and Ammonia levels, and high peak levels of
TDS during runoff events. The Glendale Plant on Cherry Creek contri-
butes significantly to the base flow of Cherry Creek which is in turn
lowest during winter. Most of the point source loads for Ammonia and
Phosphate in Cherry Creek come from the Glendale Plant. Plant source
leads account for 13% of total Ammonia loads and 35% of total phosphate
loads in the Cherry Creek basin. Removal of Phosphate from the Glendale
plant effluent would improve water quality, but recommended -levels for
instream Phosphate levels would still be greatly exceeded. Removal of
Ammonia from the plant effluent would be of limited value without non-
point source reductions given the cost of reducing effluent levels be-
low the current 5 mg/1. The high levels of TDS during runoff events re-
inforces the conclusion that this is essentially a non-point source
problem. There is no current explanation as to why peak TDS levels are
highest on Cherry Creek. It is suspected that the major source of TDS
is Speer Boulevard which parallels Cherry Creek on both banks for over
three miles downstream from Glendale. Discharges of roadway runoff
carrying traffic generated pollutants and deicing chemicals into Cherry
Creek may constitute a major non-point source.
Sand Creek Basin—The water quality problems associated with TDS, FC,
and FS have been previously discussed and are principally a non-point
source problem. The remaining major problems on Sand Creek involved
Ammonia, Phosphate, and to a lesser extent 8005. Table II-I shows that
the point source contributions are 20%, 18%, and 2% respectively of total
basin loads on an average basis. However, during periods of low or in-
termittent flow, point sources strongly determine water quality in Sand
Creek. The major point source on Sand Creek is the Aurora treatment
plant and it contributes significantly to water quality problems during
base flow conditions. Effluent levels in 1972 for Ammonia and Phosphate
were 10 mg/1 and 8 mg/1 respectively. Reductions in these levels would
benefit instream water quality, but recommended levels would still be
exceeded.
Clear Creek Basin—The major causes of water quality problems associated
with BOD,-, Ammonia, and Phosphates are the point sources discharging to
11-41
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Clear Creek. Water quality in Clear Creek is determined by a complex
interaction of seasonal flow variations, diversions, irrigation re-
turn flows, and discharges from wastewater treatment plants. Deter-
mining the importance of any one of these influences in any detail is
not possible with existing information. Water quality modeling infor-
mation from DRCOG's 208 investigation is available only for the head-
waters above Golden, and at the mouth of Clear Creek.
There are five wastewater treatment plants discharging to Clear
Creek. They are the Coors, Wheatridge, Clear Creek Valley, Arvada, and
Crestview treatment plants. In 1972, the Coors plant effluent repre-
sented over 50% of total point source loads for Phosphates, 12% for
Ammonia, and 60% for 8005. 1976 effluent monitoring data indicates about
the same percentages for Phosphates and Ammonia, but that the BOD5 now
represents about 40% of total average daily point source loads.
The major diversions of irrigation water, some of which becomes
part of municipal water supplies, occur below the Coors plant. Further
downstream some additional diversions occur, but effluent from the other
four wastewater treatment plants and irrigation return flows also occur.
As a consequence, the influence of the Coors effluent on downstream water
quality is seasonal, and is essentially significant only during those
periods of the year when irrigation water diversions are small or non-
existent (generally November through March). The data in Table II-H
illustrate this point. At the mouth of Clear Creek during the winter of
1972, the level of Phosphates was 3.2 mg/1; Ammonia, 4 mg/1; and BOD5,
18 mg/1. During spring, summer, and fall, these levels were 1.4-1.7
mg/1 for Phosphate, 1.2-1.5 mg/1 for Ammonia, and 8 mg/1 for BOD,-. These
decreases are due to increased flow in Clear Creek causing dilution, in-
stream processes which are temperature sensitive and which reduce flow
carrying Coor's discharged pollutants. Thus, the downstream discharges
from the other four wastewater treatment plants are a major cause of poor
water quality in the lower half of Clear Creek during Spring, Summer and
Fall.
South Platte—Point sources of BODc, Ammonia, and Phosphate clearly domi-
nate over non-point sources in the South Metro portion of South Platte
river (upstream from Bear Creek). These loads come from the Littleton
and Englewood wastewater treatment plants. Although a new satellite
plant to treat both Englewood and Littleton wastewater is under con-
struction, these point sources will continue to dominate water quality
in this portion of the South Platte river.
In the South Platte between Bear Creek and 38th Avenue
(about one mile downstream from Cherry Creek), non-point sources
clearly dominate. The discharge from the South Lakewood wastewater
treatment plant does contribute significant quantities of Ammonia
and Phosphate, but the water quality is already degraded because of
discharges from the Littleton and Englewood plants.
11-42
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The impact on water quality of the discharge from the Metro-
politan Denver Sewage Disposal District No. 1 Plant is overwhelming
on water quality in the South Platte downstream from the plant. This
is not surprising considering the fact that about 40% of the total
flow in the South Platte in 1972 was represented by the MDSSD No. 1
discharge. The percentage becomes 60-70% during winter low flow
periods. As shown in Table II-I, pollutant loadings from the MDSSD
No. 1 Plant represents about 75% of the total point and non-point
Ammonia loadings in the entire Denver area. Comparable percentages
for BOD5 and Phosphate are 45% and 60% respectively. However, even
if the MDSSD No. 1 plant discharged pure water, recommended levels of
water quality in the South Platte would still be routinely exceeded.
Biology
Human settlement in the plains area has greatly change the local
ecology of the Denver area through alterations in land use and the in-
troduction of non-native vegetation and animals. Urbanization to a
great extent has removed many wildlife habitat areas from the region.
Despite these changes, several areas still retain much of their ori-
ginal steppe community characteristics. Other areas, modified by
human land use have actually replaced some previously lost habitat
and increased the diversity of the local environment. These are spec-
ial habitat areas which are important to plant and wildlife ecology
and do not tolerate great changes. A mapping of these sensitive areas
is shown on Map F. Although there is a potential for several rare or
endangered animal species in the area, none of the area's plant spe-
cies are considered to be rare or endangered.
Within the Denver area, sensitive environmental areas are gener-
ally associated with watercourses and bodies. While major river
and stream systems provide valuable wildlife habitat, the area's
poor water quality limits the populations and species diversity of
the area's wildlife. Channelization of streambeds has greatly re-
duced this habitat along some stream sections. Gravel pit ponds,,
irrigation ponds, lakes and reservoirs provide important aquatic
nesting, resting and feeding habitats for waterfowl and shore birds.
The fringe areas of ponds and lakes, together with stream meanders
provide intermittant march habitat for wildlife as well. Several
heron rookeries are located in protected areas. Cottonwood and
will groves creates gallery forests along watercourses which pro-
vide important wildlife refuge areas and visual relief from the
surrounding flat plains.
In the outlying areas, human activity is less intense and
many areas still retain much of their natural condition. Selec-
11-43
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ted prairie-grassland areas show examples of the native vegetation
and habitat prior to conversion to agriculture. Numerous prairie
dog towns are found in areas removed from human disturbance and in-
vasion by domestic animals. The historic range of the black-footed
ferret which is protected by State and Federal regulations coincides
closely with its prey species, the prairie dog. The changing prairie
habitat and prairie dog control programs have indirectly, but strong-
ly affected the black-footed ferret by reducing its prey. Of the
larger grazing animals, black-tailed deer are somewhat tolerant to
human presence and are often found in the lower foothills and grass-
lands area up to the periphery of developed areas. The formerly wide
ranging pronghorn antelope are found in the upland grassland and
prairie areas in the southern part of the study area. Elk and big-
horn sheep are generally confined to the higher elevation forest and
brushland areas, but do descend to critical wintering areas in the
foothills during extreme winter weather conditions. Peregrine fal-
cons, an endangered species, have been occasionally observed in the
mountainous forest and brushland areas. The Denver plains area may
have some value as a feeding range for the species. Within Colorado
the white pelican is considered endangered as a nesting summer resi-
dent. White pelicans may be found at several reservoirs along the
South Platte River. River otters are generally rare in Colorado and
intolerant of human presence. Scattered sightings have been report-
ed along the South Platte River drainage in Weld County outside of
the Denver area.
Forest, brushland and prairie-grassland areas are important
habitats which are susceptible to wildfires. The fire hazard is re-
latively much higher along the periphery of deveoped areas and rural
roadways. The East Slope of the Front Range from piedmont areas up
to approximately 2,424 m (8,000 ft) is considered to have the most
severe fire potential.
Energy
In the Denver area nearly 75 percent of all petroleum products
are consumed by the transportation sector compared to 50 percent
nationally. Petroleum products represent 42 percent of the total
energy supply utilized in the area which is comparable to the na-
tional percentage. The industrial, residential and commercial sec-
tors of the economy have nearly 60 percent of their energy needs
supplied by natural gas. Natural gas supplies 41 percent of the
region's total energy demand whereas natural gas supplies about 31
percent of national energy demand. Projected shortfalls in supplies
of natural gas will pose a constraint on growth after 1980. In the
long term, increased reliance on coal-based electrical generation
will force increased competition for available supplies of water
which are necessary for coal mining and processing and air pollu-
H-44
-------
tion abatement. Water, being a limited resource in the area at
present, will become increasing more so in the future.
Historical Features
After becoming a part of the United States in 1803 as a re-
sult of the Louisiana Purchase, the natural resources of the Denver
Region attracted fur traders, gold miners, ranchers and farmers.
Following the discovery of lode deposits in the mountains in the
mid and late 1800's, the region's population grew rapidly and the
city of Denver became a cultural, political and financial center.
The region's historical sites are concentrated and distributed in
several areas reflecting the influences of major events such as
the gold rushes and statehood. Sites concentrated along the edge
of the mountains served as sources of supply and recreation for the
mining populations. The concentration of sites in the Denver down-
town area developed as Denver became the major supply point for the
gold fields and eventually the state capitol. Out on the plains,
sites are situated along the major cattle, stage coach and pony.ex-
press trails which served the region before the advent of the tele-
graph and the railroad. Individual sites, mostly farm and ranch
houses, are scattered throughout the plains area. Appendix Table
A-8 lists the major historical sites in the Denver Region which are
mapped on Map G.
Outdoor Recreation Sites
Several types of recreation areas such as the South Platte
Greenway, a proposed trail system along major streams linked to
the Greenway, -and the Barr Lake and Barr Lake Duck Club are located
near various existing and proposed wastewater facility sites (See
Map G). Many of the recreation sites are located downstream from
the Denver Metro Wastewater Treatment Plant. Some counties have
acquired park and open space lands which are to be developed as
populations grow over the next fifteen or more years. Numerous
parks and open spaces are currently being planned or proposed by
the cities of Littleton, Denver, Lakewood, Wheat Ridge, Arvada and
Aurora. A major problem being experienced by the Denver area's
park agencies is vandalism and misuse of park and open space areas.
This problem may become more difficult to deal with in the future
as service areas become larger and uses become more intense.
The recreational potential of most streamside parks, hiking
trails, and bicycle paths is limited by current water quality
problems.
H-45
-------
Aesthetics
Amenities which make a strong contribution to the Denver
region's quality of life include the temperate arid climate, visual
relief from the high plains topography by the abrupt face of the
Front Range, recreational potential of the Rocky Mountains, land-
scaped and semi-natural areas within the urban area, open space
areas surrounding the city, and social, cultural and economic
institutions which strongly govern urban life styles. Of these,
visual and open space amenities are the least well-defined and
also the most susceptible to change. Visual perceptions range
from panoramic background views to areas of immediate perception
to distinct scenic or contrasting features. Further high-rise
development in central business districts can significantly alter
these perceptions. Examples of well-known scenic features within the
Denver Region are given in Appendix Table A-9, and their locations
are shown on Map G. Open space can be described ag land left un-
developed for the purposes of recreation, scientific study, pro-
tection of wildlife, watershed, or a buffer to urban encroachment.
Waste Land Disposal and Reuse
In many areas, sludge, the treated solid component of sewage,
is sold or applied to city—owned parks and other green areas as
a soil conditioner or disposed in landfills. The largest producer
of sludge in the area, the Northside/MDSDD #1 wastewater treatment
complex*, dewaters undigested sludge to reduce its volume and
trucks it to the Lowry Bombing Range where it is mixed with soil.
Because the high volume of sludge disposed at the range, this
practice must be discontinued in the near future, and alternative
plans are now being developed.
Improvements are under way and plans are being made to remedy
the treatment complex's sludge disposal problems. Anerobic digesters
are being constructed at the Denver Metro Plant that could eventually
reduce the volume of sludge and make it more acceptable for land
application. A long-range plan is being considered to transport
sludge via pipeline to a drying distribution site in Western Adams
County (see Figure II-J) for drying and subsequent sale to farms
in the area. EPA has prepared a draft EIS on this plan. Plans for
an airport in the vicinity of the site are being considered by
Adams County.
Reuse of treated wastewater for urban and agricultural
irrigation already occurs in the Denver region. Reuse is both
direct and indirect. Direct reuse is the direct conveyance of
treated wastewater
*This complex consists of two separate treatment plants. One is oper-
ated by the City and County of Denver, the other by the Metropolitan
Denver Sewage Disposal District No. 1
11-46
-------
from the treatment plant to point of use. Indirect reuse involves
the exchange of treated wastewater discharged downstream for water di-
verted upstream which would normally be available for downstream users.
Current and planned practices of direct and indirect reuse are more
fully explained in Appendix A,
About 20,800 acre feet C6,800 million gallons) of treated waste-
water is currently directly reused, The vast majority, about 19,900
acre feet per year, is used for agricultural irrigation after diversion
from the MDSSD No. 1 plant to the Burlington Ditch by the Denver Water
Board. This diversion represents about 14 percent of the total yearly
discharge of the plant. A portion of the effluent conveyed to Barr Lake
contributes to the water quality problems of that recreational and wild-
life area. The remaining 900 acre feet is used for urban irrigation of
parks and golf courses. The cities of Northglenn and Westminster are
currently completing arrangements for direct reuse of treated wastewater
for agricultural irrigation in exchange for upstream diversions of water
for municipal use. Also, Denver is planning to construct a 1.0 million
gallon per day pilot treatment plan for producing potable water from
wastewater effluent. Ultimate plans are for a 100 million gallon per
day plant if safety consideration and public acceptance permit,
All reuse schemes are in effect a means of increasing water supply.
They may also have the potential of improving stream water quality by
diverting relatively polluted discharges from streams to some reuse
such as irrigation. Water quality "benefits" are sometimes difficult
to define because a substantial portion of the flow in a particular stream,
such as Cherry Creek, may depend on point source discharges. Benefits
from improved quality in terms of pollutants may be offset by diminished
flow. The communities in the Denver region are interested in reuse
schemes because the'y stretch or augment existing water supplies. This
interest will continue and intensify.
In effect, the waters of the South Platte are used many times by
municipalities and agriculture before reaching the Nebraska State line,
A situation not uncommon on most major rivers of the United States.
Traffic
In 1974, 97% of all intracity trips in the region were made by
automobile. The existing highway system become overloaded at peak
traffic times in several areas and the situation is expected to worsen
due to further population growth and suburban development patterns and
locations, The nature of these overloaded conditions is generally a
reduction of traffic flow speeds by 10-30 mph. Although the "linear
parking lot" traffic jam situation typical of other major cities such
as New York and Los Angeles is rare in Denver, it is not an unheard of
occurrence. Some of the major highways and arterials presently ex-
periencing rush hour overload conditions include:
11-47
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I , - - -T
^,H- 1 • "W •
K / :-^^
G I L.P I V" DENVER— ^_
, , NORTHSIDE .3
5LUDGE[5)RYING
DISTRIBUTION
A . R H A ,P A H O.E
LOWftY
BOMBING
RAN$E |
*.."' J^r_ ^1' "_>''J • ;Y^t'E F F B^ S O
*3 T'
i > i
LAND WASTE
TREATMENT SITES
- t_ -f^ :— —
,«;js&-tr " -f-
-------
1. Broadway Avenue from the Central Business District
(CBD) to Englewood.
2. 1-25 (Valley Highway) from the Denver-Boulder Turnpike
Interchange south past U.S, Highway 6.
3, The I-70/I-25 interchange nicknamed the "mousetrap."
4. Federal Boulevard,' Speer Boulevardt Alameda Avenue,
and Santa Fe Drive as they approach the CBD,
5. Wadsworth Boulevard, Hampden Freeway, Sheridan
Boulevard and Colorado Boulevard as they approach
the major thoroughfares carrying traffic in and
out of the CBD,
Present attempts to remedy traffic problems include further high-
way construction such as that being planned in the southwest area
of the region to relieve traffic congestion. Also, various types
of mass transit systems are being studied by the Regional Trans-
portation District (RTD).
Plutonium Contaminati-on
The extent and significance of plutonium-in-soil and airborne
contamination caused by the plutonium processing plant at Rocky
Flats is under intense investigation by State and Federal agencies.
Various agencies are concerned that plutonium contamination may
have occurred as a consequence of the fire at the Rocky Flats Plant
in 1969. The transport of plutonium contamination easterly from
the plant is known to have occurred. Whether contamination levels
are hazardous to human health has not been decisively determined.
Investigations are now underway to determine the extent of con-
tamination of the ground surface, Great Western Reservoir, Stand-
ley Lake, and whether wind pickup of surface contamination repre-
sents a hazard. Ultimately, certain land areas generally east of
Rocky Flats may be banned from residential development.
11-49
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SOCIO-ECONOMIC ENVIRONMENT
The term "socio-economic" embraces all those conditions and ac-
tivities that relate to man's habitation and use of his environment.
Housing, employment, community services and facilities, and the in-
stitutional structure through which demands for these good and ser-
vices are communicated all form part of the socio-economic setting.
This section presents first basic data on the regional economy, popu-
lation and land use. Subsequent sections discuss community services
and facilities, agricultural land use, and regional planning and
policies.
Regional Economy, Population and Land Use
The Economy—
The Denver region enjoyed a significant economic expnnsion in the
past three decades, and particularly in,the 1960's. Employment in all
major nonagricultural sectors of the region's economy grew at a faster
rate than in the nation during the second half of the 1960's and are
expected to continue to surpass national growth through the 1970's (Ref.
905). During the 1940-1970 period, employment in the five-county Denver
region increased at an average rate of 3.7% per year, while state and
national employment grew at rates of 3.0% and 1.7% respectively (Ref.
259). In 1970, about 60% of Colorado employment was located in the
five-county Denver region.
In 1975, nonagricultural employment in the Denver region numbered
about 661,400. About 65% of these jobs were concentrated in three
section: trade, services and government (including military). Den-
ver's economic mix is more strongly concentrated in the service-pro-
ducing sectors than in the goods-producing sectors. In the U.S. as
a whole, 23.8% of nonagricultural employment is in manufacturing;
in Denver, the comparable proportion is 14.3% (Refs. 999 and 259).
However, a few manufacturing activities are significant exceptions.
Machinery.electrical products, luggage and rubber manufacturing are
considered major contributors to the "exports" of the Denver region;
that is, economic activities which result in the sales of products to
markets outside the region. With these exceptions, however, most of
Denver's export activity is in the service sectors: TCU (transporta-
tion, communications and utilities), trade, services and FIRE (fin-
ance, insurance and real estate). Employment concentration in these
sectors reflects Denver's role as a regional finance and distribution
center for the mountain states.
Recent trends in employment suggest that strength in the service
sectors is becoming more marked. While there has been significant
growth in all economic sectors since the mid-1960's, growth in trade,
11-50
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FIRE and services has been much more rapid than in manufacturing, as
Table II-j indicates. However, construction employment continues to
grow quite rapidly - a tangible indicator of growth in all sectors.
A significant recent trend in employment growth is in the mining
sector. This sector includes extraction of minerals occurring na-
turally (coal andores, liquid petroleum and natural gas), quarring,
well operation-exploration and development, and related off-site em-
ployment. Much of the growth in downtown office employment in the
Denver region in recent years is reprotedly in the extractive indus-
tries, with a number of major firms using Denver as the base from
which to supervise exploration and energy development activities in
the mountain states. This trend has created a surge in demand for
downtown office space, which has been experiencing very low vacancy
rates; downtown office construction is expected to continue to pros-
per, at least in the short run (Trenka, pers. comm.).
The distribution of employment among the counties of the region
has been changing over time: as the four outer counties have urbani-
zed, Denver (City and County) has represented a decreasing share of
the region's employment. Figure II-K depicts shifts in county shares
graphically.
Population—
In recent years, Denver has been one of the nation's fastest-
growing metropolitan regions. During the 1960's, the Denver metro-
politan area grew annually between 3% to 4.6%, considerably more
rapidly than the state's 2.3% average annual growth. Over half of
Colorado's population lives in the five-county region (Ref. 304).
Figure II-K presents a graphic depiction of the distribution of the
region's population by county in 1960 and 1970. Table II-K presents
demographic characteristics of the Denver region's population in
1970.
Population growth is composed of two elements: the excess of
births over death ("net natural increase') and the excess of in-
migrants over out-migrants while death rates remained fairly stable,
birth rates have dropped over 40% since 1960. A majority (60% in
1975) of the total population increase in the Denver region is at-
tributable to net in-migration. Table II-L presents county esti-
mates of population change of both types in 1975.
In the period from 1940 to 1970, annual net in-migration to the
region averaged 15,100 (Ref. 401). Recent years have seen the suburban
counties - particularly Jefferson-attracting the lion's share of net
in-migrants, as Table II-M indicates. It should be kept in mind, how-
ever, that net migration figures do not reflect total movement. The
City and County of Denver may be receiving a large absolute number of
newcomers, but its loss of residents to the suburban counties may ex-
ceed the number of new residents it receives from outside the region,
at which point its absolute population declines.
11-51
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Table II-J. RECENT TRENDS IN NONAGRICULTURAL EMPLOYMENT BY
SECTOR IN THE FIVE-COUNTY DENVER REGION
Sector
Mining
Construction
Manufacturing
TCU (transportation, communications
and utilities)
Trade
1— 1
1 |
^ FIRE (finance, insurance, real estate)
N3
Services
Government (including military)
Total Nonagricultrual Employment
Annual Growth
1964-70
2.8
3.6
4.7
3.0
4.5
4.1
5.9
4.4
not
tabulated
Rates, %
1970-75
5.7
5.6
1.7
2.3
4.8
6.9
5.4
3.9
4.2
Current
Employment
7,800
42,500
94,700
42,100
161,600
44,900
143.400
124,400
661,400
Source: DRCOG. Figures for 1964-70 cited in Ref. 304 and figures for 1^70-75 cited
in Ref. 259.
-------
EMPLOYMENT
POPULATION
I960
197D
I960
1970
Ln
U)
1 - ADAMS
2 - ARAPAHOE
3 - BOULDER
4 - DENVER
5 - JEFFERSON
''EXCLUDES EASTERN ADAMS AND ARAPAHOE COUNTIES
AND WESTERN BOULDER COUNTY. SOURCE: REF 262.
REGIONAL EMPLOYMENT
AND
POPULATION BY COUNTY3
-------
Table II-K. DEMOGRAPHIC CHARACTERISTICS OF DENVER SMSA°
POPULATION, 1970
H
1
Ul
-F-
Family Incotne Number of
Categories Families &
<$3,743b 20,572 6.8
<$4, 999 43, j.72 14.2
$5,000 to
$14,999 185,713 61.0
>$15,000 75,580 25.0
Median $10,777
Age
Categories Persons
<15 362,195
<19 477,904
20 to
54 564,078
>55 185,547
>65 05,046
Median ca.
%
29.5
38.9
46.0
15.1
7.7
26.5
Ma .nor Ethnic
Groups # %
White 1,021,477 84.6
Spanish 13 11<3
surname
Black 50,159 4.1
a. Denver SMSA in 1970 includes Adams, Arapahoe, Boulder, Denver and Jefferson Counties.
b. Poverty level.
<, means less than
>, means greater than
Source: Ref. 304
-------
Table II-L. COMPONENTS OF ESTIMATED RESIDENT
POPULATION CHANGE, 1975
M
H
Ul
Ol
County
Adams
Arapahoe
Boulder
Denver
Jefferson
TOTAL
Births
3,721
2,880
1,965
6,468
4,289
19,323
Deaths
1,110
1,060
879
4,918
1,578
9,545
Net Natural
Increase
2,611
1,820
1,086
1,550
2,711
9,778
Net
In-migration
389
5,280
3,614
-4,950
12,289
16,622
Total
Increase
3,000
7,100
4,700
-3,400
15,000
26,400
Source: Ref. 208
-------
Table II-M. DISTRIBUTION OF NET IN-MIGRANTS
TO FIVE COUNTIES, 1970-72
Year
1970
1971
1972
Adams
County
20.0%
19.5
13.3
Arapahoe
County
18.2%
24.1
25.9
Boulder
County
13.8%
16.4
16.5
Denver
County
2.3%
2.7
1.5
Jefferson
County
45.7%
37.3
42.8
Source: Ref. 128
The general pattern of population change in the region has
been that of a central city (Denver) representing a declining pro-
portion of the regionrs population. Since 1960, the population of
Denver (City and County) has grown more slowly than at any other
time in the twentieth century. One study points to the increasing
resumblance between Denver's patterns of population change and those
of older urban core cities, especially in the East and Midwest:
The overall picture presented is one of Denver as an
aging urban core city increasingly populated by the
poor; the less educated; the minorities; the less
easily employed; the elderly; and the working young
adult households. It is also one of Denver surrounded
by a solid suburban ring populated by the white major-
ity; the affluent; the better educated; the family
households with children and with adults in their most
productive years; and the higher skilled and more easily
employable. (Ref. 905.)
In-migrants to Denver tend to be the elderly, minorities, and
young adults; this pattern may be accompanied by higher employment,
lower levels of educational attainment and lower household incomes.
The pattern will cause the existing social dichotomy between core
city and suburb to become more pronounced over time.
Land use—
The most striking characteristic of regional land use is its
dispersed pattern and Iwo density. In the City and County of Denver,
population density was about 5,418 persons per square mile in 1970,
with about 200 persons per_ square mile in the four suburban counties
II-56
-------
for an SMSA average of 335. Of the 34 metropolitan regions having
populations exceeding 500,000 in 1970, only five (Dallas-Fort Worth,
Houston, San Diego, Riverside-San Bernardino, and Portland) had lower
densities. In fact, population density in the Denver region was less
than that in many suburban counties of other regions. Isolation from
other urban areas, preference for open space and the high mobility
made possible by the extensive highway network are reasons given for
the overall suburban density of this urban region (Ref. 304).
Growth in recent years has shifted the distribution of many land
use categories from the City and County of Denver to the outlying
counties. In the case of single-family residential, the regional
concentration of this development shifted to Jefferson between 1960
and 1970. Multi-family housing, too, has increasingly been a subur-
ban phenomenon, and retail/service commercial activity has followed
the shift in population. Suburbanization of major industry has be-
gun recently and is expected to continue (Ref. 905). Agricultural
land use declined by about 7%; this decline is discussed in Section
IV. Table II-N presents a land use tabulation by county for 1960
and 1970.
Many local officials have observed that land use patterns in the
region have thus far developed more in response to economic pres-
sures than as the result of conscious planning. This has occurred
in part because existing zoning is in conflict with the regional
plan: while a regional population forecast of 2.35 million has been
adopted, DRCOG found in 1972 that the population holding capacity of
zoned land exceeded six million. The study of existing zoning con-
cluded that the region was greatly overzoned; "at present, every
city and county has zoning far in excess of that needed to accommo-
date its present population" (Ref. 258).
Under these circumstances, zoning has not been an effective tool
in implementing land use planning. Much of this overzoning is re-
ported by local jurisdictions to have been the result of pre-zoning
when annexations took place. As a practical matter, rezoning can-
not easily be accomplished until the land is proposed for develop-
ment, and even then rezoning may not be possible. Many local public
officials interviewed in the course of this study expressed the view
that a state law requiring zoning to be consistent vrith comprehen-
sive planning would help to solve this problem; however, some also
pointed to the common acceptance of the zoning map as the community
comprehensive plan. No ready solution to the over-zoning problem
was identified.
11-57
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Table II-N. COUNTY LAND USE SUMMARY, 1960 AND 1970
(1000 acres)
M
M
I
On
00
—
County3
& Year
Adams
1960
1970
Change
Arap&hoe
1960
1970
Change
Boulder
1960
1970
Change
Denver
1960
1970
Change
Jefferson
1960
1970
Change
Total3
1960
1970
Change
Single-
family
6,266
9,947
+ 59%
6,688
11,797
+76%
5,935
9,775
+65%
15,146
16,918
+12%
11,325
18,148
+60%
43,360
66,585
+47%
Multi-
family
265
928
+250%
343
653
+90%
382
951
+149%
2,306
2,998
+30%
411
892
+117%
3,707
6,422
+73%
~— — — — — ^__
Commer-
cial
482
994
+106%
360
760
+111%
564
910
+61%
1,253
1,672
+33%
638
1,338
+110%
3,297
5,674
+72%
" ' -Hi.-
Ser-
vices
54
177
+228%
120
310
+158%
72
153
+112%
539
613
+14%
951
966
+2%
1,736
2,219
+28%
i
Industrial,
Transporta-
tation & Com-
munications
10,813
14,155
+ 31%
7,990
10,190
+27%
7,510
9,236
+23%
19,781
23,000
+16%
13,738
17,834
+30%
59,832
74,415
+24%
Parks &
Recrea-
tion
320
1,173
+267%
4,642
5,187
+12%
46,897
47,781
+2%
3,079
3,559
+16%
125,497
128,127
+2%
180,435
185,827
+3%
& Semi-
public
18,676
18,642
0%
13,077
7,760
-41%
3,128
3,781
+21%
4,802
3,813
-21%
6,059
6,648
+10%
45 , 742
40,644
-11%
Agricul-
tural
189,542
177,241
-6%
80,161
74,923
-6%
138,958
133,867
-4%
7,403
1,985
-73%
76,867
71,335
-7%
492,931
459,351
-7%
Vacant
16,590
19,751
+19%
13,428
15,229
+13%
79,474
76,466
-4%
9,122
8,873
-3%
262,680
252,878
-4%
381,294
373,197
-2%
Total
243,008
126,809
282,920
63,431
498,166
1,214,334
aExcludes western Boulder and eastern Adams and Arapahoe Counties.
Source: Ref. 205
-------
Community Services and Facilities
A wide variety of government services are provided by local
jurisdictions in the Denver region. These jurisdictions include
25 municipalities and 201 special service districts within the
four-county region (Adams, Arapahoe, Denver and Jefferson Counties).
A recent study of taxation and finance in the region (from which the
data in this section are taken) found that these jurisdictions spent
approximately $920 million in 1974 ($747 per capita) as compared with
total revenues to the State of Colorado of $958 million in fiscal
year 1974-75 (Ref. 987).
The major local cost is for public education, which ranges from
$232 (Denver) to $320 (Arapahoe) per capita; total county per capi-
ta expenditures (that is, total expenditures of all local service
agencies and municipalities within county boundaries) ranged from
$571 (Jefferson) to $835 (Denver) per capita. The service ranking
second in per capita cost is water and sewerage. For a number of
reasons, including the fact that costs paid to private water and
sewerage agencies are not included in the estimates of public costs,
average water/sewerage costs were found to vary widely throughout
the Denver region. Compared to a regional average of $70 per capita,
the county average (1974) are $92 (Adams), $75 (Arapahoe), $60 (Den-
ver) , and $48 (Jefferson). Among municipalities, even greater vari-
ability was observed: Commerce City has per capita water/sewer-
age costs of $142; Englewood, $93; Golden, $66; Arvada, $46; Wheat-
ridge, $28.
The Denver Metropolitan Study report on finance and taxation
(Ref. 1005) considers several issues related to revenue, expendi-
ture and service delivery organizations. On the question of dis-
tributional equity (taxation burden relative to ability to pay),
the study found that the City and County of Denver, with 43% of
the population in the four-county region, accounts for 42% of the
gross personal income. "This suggests that on the aggregate the
City/County is not seriously disadvantaged in terms of ability
to pay as measured by gross personal income." The study did point
to a disparity among counties in terms of personal income per
capita; Arapahoe, $4994; Jefferson, $4718; Denver, $4260; Adams,
$3516. "The real disparity within the region is between Adams
County and the other three counties."
A second important issue is that of the organization of service
delivery. The 201 special districts in the four counties ac-
count for 10% of all local revenues. Because these districts
cut across municipal, county and other special service district
boundaries, they make efficient planning and administration of
services extremely difficult. Even obtaining information from
11-59
-------
such districts (one-third have no paid staff) proved very diffi-
cult to the Metropolitan Study research team. The study con-
cluded that fractionated districts G-) make accountability uncer-
tain; (2) result in higher costs and (3) involve double taxation.
It is the special district system which is responsible for the wide
variation in municipal property taxes, with the resulting unevenness
in the cost of public services to individual taxpayers.
Table II-0 present a summary of user and service charges imposed
by the local agencies proposing new wastewater facilities.
South Adams County Water and Sanitation District (SAS)—
The majority of SAS's funds in 1970 came from service charges
(46.7%) and a mill levy (47.0%). Most of the remainder of the
funds were tap fees and interest, with smaller amounts produced by
special improvement charges, plant investment fees, special assess-
ments, inclusion fees and permit fees (tax inspection). SAS charged
a $200 tap fee per unit in 1972 and a monthly residential service
charge of $2.00 per unit. The district had general obligation bonds
outstanding in 1973 which were scheduled to be retired that year
(Reference 120).
Cities of Littleton and Englewood—
Both cities receive funds from service charges and tap fees. In
addition, Littleton receives funds from interest, special improve-
ment charges and special assessments. Englewood charges a plant
investment fee and has a tap inspection fee. Englewood has a tap
fee of about $100 for residents and $115 for non-residents based on
square footage or acreage. Littleton's residential tap fee is per
unit and is typically $300 for residents and $450 for non-residents.
Englewood's per unit service charge is $1.25 for residents and $1.75
for non-residents. Littleton service charges are a percent of a
unit's water bill. The average monthly charge is $2.90. Englewood
currently has refunding revenue bonds outstanding.
City and County of Denver (CCD)—
CCD receives almost all its revenue (95.4%, 1970) from service
charges. The remainder comes from interest and special improve-
ment charges. CCD does not charge a tap fee. The service charge
is based on a percent of the water bill. Service charges averaged
$3.25 per month for residents and $3.08 per month for non-residents
in 1972 (Reference 120).
In 1972, CCD sold $20 million worth of general obligation
bonds. These obligations are binding on the entire city and county,
not just the Wastewater Division. It is presumed some or much of
II- 60
-------
Table II-O. SUMMARY OF AVAILABLE INFORMATION ON USER CHARGES
Agency
South Adans County
Water and Sanita-
tion District
City of Littleton
City of Englewood
H City and County of
• Denver, Wastewater
^ Division
I-1
Metropolitan Denver
Sanitary Disposal
District ,';!
City of Broomfield
City of Westminster
South Lakewood Sani-
tation District
Facility Plan
service area/project
South Adams
Littleton/ Englewood
Cherry Creek/
Goldsmith Gulch
Northside Plant
Lower South Platte
Clear Creek
Sand Creek
main plant expansion
Big Dry Creek
Residential
$2.80/moa
$2.75/raoa
% of water
billb
$1.25/moa
within city
$1.75/mob
outside
city
101% of
water bill;
water rate ™
$.33/1,000
gal.a
-
$3.50/mob
$3.00/raoa
within city
53.50/Eo
outside
city
none
Service charge
Conunercial
$2.80/moa +
25% of water
charges above
53,000 gal.
$2.75/moa per
equivalent
dwelling unit
$1.25/moa
95X of water
bill2
-
per unitb +
X of water
bill
$.35/1,000
gal. water
useda
none
User charge rate structure
Industrial Residential
percent of $235/unita
metered water
consumption
meter sizeb $300/unita
7. of water $300/unita
billb
% of water $300/unita
billb
-
per unitb + $580/unita
% of water
bill
negotiable $455/unita
contract
none $401/unitd
Tat) fee
Commercial Industrial Remarks
per unitb per unit received •». 47.02 of
(negotiable) revenue from mill
levy in 1972°
per sq ft negotiated
or negoti-
ated
per sq ft per sq ft
or acreage or acreage
none noneb
>33SDD#1 charges
user on following
basis0:
flow (3 45.51%
BOD @ 30.SSJ
SS (5 23.612
per unit per unit
per pipe per pipe
size size
4.16-mill levy for
general revenue
Reference 976
Reference 120, 1972; creferenca 318, 1976; dpeteonal conanunication, John Krus, 8 February 1977.
-------
this capital was used to fund the plant improvements to the
Northside plant which are now being completed.
Metropolitan Denver Sanitary Disposal District No. L (MDSDD //I) —
All income is based on charges to other district using MDSDD
#l's treatment facilities. Charges are based on volume and waste-
water characteristics. The district meets all operating and mainte-
nance costs and payments on long term debts, which consists primarily
of revenue bonds, from these charges. A small amount of income is
derived from interest on unused capital.
Cities of Broomfield and Westminster—
Both cities receive all of their revenues from service charges,
tap fees and interest. Both had revenue bonds outstanding in 1973
(Reference 120). Broomfield has -a tap fee of $150 which includes
a plant investment charge. The fee is the same for both city and
non-city residents. Westminster charges a $180 tap fee for city
residents and $270 for those outside the city. Broomfield charges
industrial and commercial users an undisclosed flat unit rate
while Westminster charges per pipe size. Broomfieldfs service
charge is $3.50 per month for all residential users. A flat rate
plus a percent of water bill is charged to industrial and commer-
cial users. Westminster charges flat rates of $3.00 per month for
city residents and $3.50 per month for non-residents. Commercial
and industrial users' rates are based on water use or negotiations
between the city and individual user.
South Lakewood Sanitation District (SLSD)—
South Lakewood Sanitation District receives revenues from
two sources, a tap fee of $401 per unit and an ad valorem tax
of 4.166 mils (Ref. 966). Current treatment costs for operating
and maintenance have been reported to be $230-240 per million
gallons (Ref. 967). SLSD currently has no service charge. As
there is little industry in the district, SLSD officials hope
that legislation will be passed to permit continued use of ad
valorem taxes to finance the local share of wastewater facili-
ties costs. If such legislation is not passed, the district
would consider changing to a service charge revenue system in
order to qualify for Federal grant money. SLSD has no out-
standing bond issues.
11-62
-------
Agricultural Land Use
Land in Agricultural Use—
The fringes of the Denver Metropolitan area contain a great
proportion of highly productive farmland. Soils are generally deep,
friable, well-drained, flat and fertile. Table II-P shows a total
of 301,790 acres (1973) of existing prime and non-prime agricult-
ural land in the areas likely to experience growth pressures before
the year 2000. The figures shown are for the Denver Regional Coun-
cil of Government's (DRCOG) "empiric counties", i.e. those urban
and urbanizing portions of the political counties in the region
which provide the areal basis for population projections.
Table II-P: 1973 ESTIMATES OF AGRICULTURAL ACREAGE BY EMPIRIC'
COUNTY IN THE DENVER REGION
County
Adams
Arapahoe
Boulder
Denver
Douglas
Jefferson
Weld
TOTAL
Rangeland
10,750
38,940
30,000
3,470
0
41,540
0
124,700
Non-Irrigated
Cropland
16,070
20,550
10,950
1,100
0
10,750
0
59,420
Irrigated
Cropland
32,790
830
74,120
2,510
0
7,420
0
117,670
Total
Agricl.
Landsb
59,610
60,320
115,070
7,080
0
59,710
0
301,790
Empiric County boundaries designated by DRCOG, 1973
DTotal Agricultural lands within Empiric Counties (Reference 257)
11-63
-------
Table II-Q shows a total of 392,040 acres (1973) of existing
prime and non-prime agricultural lands in the region beyond the
boundaries of the empiric counties. More simply stated, Table
II-N is an estimate of agricultural lands in the region which are
not expected to experience significant pressures to convert to
urban uses before the year 2000.
Table II-Q: 1973 ESTIMATES BY POLITICAL COUNTY OF EXISTING
AGRICULTURAL LAND WITHIN THE REGION'S MAJOR DRAINAGE
BASINS,3 BUT OUTSIDE THE EMPIRIC COUNTY BOUNDARIES
County
Adams
Arapahoe
Boulder
Denver
Douglas
Jefferson
Weld
TOTAL
Rangeland
0
0
51,300
0
137,560
41,140
1,430
231,430
Non-Irrigated
Cropland
2,790
24,130
8,230
0
34,960
10,300
3,540
84,050
Irrigated
Cropland
41,470'
11,410
4,120
0
7,700
1,720
9,240
75,660
Total
Agricl.
Lands
45,260
35,540
63,650
0
180,220
53,160
14,210
392,040
Major drainage basin boundaries designated by DRCOG, 1973
Total agricultural lands outside of empiric counties, but within
the region's major drainage basins (Reference 257).
Using published and other available soils information, the
"prime" agricultural lands, i.e. those lands having the fewest li-
mitations for various agricultural uses, were mapped as shown on Map
D. This map was prepared principally for regional impact assessment.
Criteria used to determine prime lands included the U.S. Soil Conser-
vation Service soil capability rating and predicted crop yields. They
did not include such site-specific variables as economic feasibility
and value, land ownership, and energy requirements for crop produc-
tion. These criteria for both irrigated and dryland operations
II- 64
-------
were mapped as accurately as the available soil maps permitted.
Areas currently in urban development were excluded from consider-
ation. However, current zoning and political boundaries did not
influence the mapping.
At the present time, most of the existing croplands mapped as
prime are under irrigation as evidenced from recent satellite photo-
graphy. See satellite photo included in Map folder.
Using a tabulation of soils types and their acreages by county,
DRCOG has estimated that there are 773,017 acres of existing and
potential prime agricultural lands in a three county area which ex-
tends beyond the study area to the west into the mountains of Boulder
County and to the east out into the plains of Adams and Arapahoe
Counties. This sum figure for prime lands is based on the total
acres of soils which qualify for classification as prime agricult-
ural land according to preliminary criteria adopted "for discussion
purposes only" by DRCOG. Table II-R summarizes the tabulation. It
is presented in its entirety in Appendix A.
Table II-R: SUMMARY OF DRCOG TABULATION OF EXISTING AND POTENTIAL
PRIME AGRICULTURAL LANDS IN A THREE COUNTY AREA OF THE
DENVER REGION
County Number of Acres
Adams 450,000
Arapahoe 229,797
Boulder 93,220
Denver Not applicable
Douglas Insufficient data
Jefferson
Weld
TOTAL 773,017
(Reference 252)
The Economic Value of Agricultural Activity—
Denver is a major agricultural and livestock trading center,
Beef cattle dominate the livestock market, while major crops in-
clude alfalfa, small grains, corn and sugar beets (Ref. 104).
II- 65
-------
Agriculture accounts for 6% of the region's employment (as compared
with 3.5% of the nation's employment) (Refs. 994 and 995). In
terms of crop values, the most important single crop is winter wheat
which in 1974 accounted for almost 43% of the value of regional
crops, as indicated in Table II-S.
TABLE II-S: VALUE OF CROP POPULATION BY COUNTY, 1974
(in 000's of Dollars)
Winter Corn (Grain Sugar All other
County Wheat & Silage) Hay Beets Crops Total
Adams
Boulder
TOTAL
13,329.
L O70
706.
OQO
18,399.
0
n
6
A
0
3,458
OQA
3,357
7,345
.0
0
.0
fi
.3
2,359
71 ft
2,219
QOQ
6,126
.5 1,333.0
1
.0 2,390.0
C
.1 3,723.0
3,866.2
fim ^
2,694.2
"^ AQ n
7,530.9
24
<;
11
1
43
,345
78^
'
,366
f>97
,124
.7
o
.8
n
.3
Source: Ref. 984
Agricultural activity in the region creates jobs in other
sectors of the economy, as Denver region firms in such sectors as
manufacturing, finance and trade provide goods and services to agri-
culture. One study traced the economic effects of agricultural ac-
tivity on irrigated lands in Adams County and found that 100 agri-
cultural jobs create the demand for 82 nonagricultural jobs, with
the majority of these in the manufacturing and service sectors (Ref.
986). This estimate includes only the direct economic effects of
agriculture; it excludes job generated within each nonagricultural
sector due to demand by other nonagricultural sectors for goods and
services needed to meet requirement of agriculturalists. If all
these inter-and intra-sectoral economic linkages were qualified,
the result would be an estimate of an agricultural "multiplier" for
the Denver region: a measure of the total economic impact of re-
gional agriculture on the regional economy. No research on this
subject was found; however, for the State of California, an agri-
cultural multiplier has been estimated as between 3 and 4, meaning
that for each $1 of agricultural production, the state enjoys $2 to
$3 of additional economic product related indirectly to agriculture
(Ref. 991).
H-66
-------
Future Prospects for Regional Agriculture—
Denver's role as a regional center of finance and trade will
permit it to continue to capture agriculture-related jobs in non-
agricultrual sectors even as agricultural activity becomes in-
creasingly distant from Denver due to urbanization and other fac-
tors. Loss of agricultural employment in the five-county regions
is a reasonable expectation. DRCOG forecasts that this decline
will be on the order of about 12% between 1975 and 2000 (Ref. 259).
This need not necessarily mean loss of production, as historically
productivity increases have more than made up for reductions in
farm labor. However, loss of agricultural land or water supply to
urban uses may result in a decline in agricultural output.
Much of the Denver region's growth since 1950 has taken place
on land formerly in agricultural production. In Adams and Arapahoe
Counties in the 1960's, about 56% of the gross addition to urban
land came out of the cropland category (Ref. 719). Notwithstanding
the conversion of agricultural land to urban uses, the total acre-
age in cropland did not decline, because land in other open land
categories (principally pasture and range land and open idle land)
was converted to cropland. However, total land in the agricultural
category did decline 33,580 acres or 7%. Similar patterns have been
noted in other regions (Ref. 719 and 127).
Indirect effects of growth are causing further pressures. These
indirect pressures are manifest principally through increases in
the cost of water and the increased demand for water by municipali-
ties. This latter point is illustrated by the current condemnation
proceedings initiated by the cities of Thornton and Westminster to
affect conversion of agricultural irrigation water rights to muni-
cipal use. Loss of water would probably result in the conversion
of irrigated cropland back to dry land farming and grazing, in-
creased land speculation, and an overall decrease in productivity
and amount of land in agricultural production. Coupled with, these
pressures, the current drought, and the unsatisfactory returns on
cultivated land farmers have experience in the last few years, are
causing serious difficulties for the agricultural sector of the
region's economy- The prognosis is not favorable.
Regional Planning Policies
Regional planning for the Denver Metropolitan area has had an
interesting and sometimes even turbulent history. Until very re-
cently, land use and transportation planning were done jointly by
an organization known as the Joint Regional Planning Program or
JRPP. The three participants in this program were the State Di-
vision of Highways (CDH), the Regional Transportation District
(RTD), and the Denver Regional Council of Governments (DRCOG).
II- 67
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Early in 1977, the DRCOG was designated as the Metropolitan Plan-
ning Organization by the Governor and, as such, is now responsible
for transportation planning. Additionally, DRCOG has had a his-
tory of being the regional land use planning and population fore-
casting body and also provides many other regional planning func-
tions. The Denver Regional Council of Governments represents 37
local governments throughout the metropolitan area. In 1973, DRCOG
adopted a Year 2000 regional land use plan (see Map I) along with
a set of policies which outline the population and land use guide-
lines for growth in the region. (See Appendix A). One of the most
significant of these policies is the statement that:
A population level below 2,350,000 should
be encouraged for the Denver Metropolitan
Statistical Area by the year 2000.
The Council of Governments is also the designated agency re-
sponsible for water quality management planning in Denver under
Section 208 of the Federal Water Pollution Control Act of 1972.
In developing this water quality plan, the DRCOG adopted an allo-
cation by municipality of the Year 2000, 2.35 million population
forecast.
Another agency responsible for regional water planning in the
metropolitan area is the Urban Drainage and Flood Control District.
The Flood Control District is responsible for comprehensive and
project planning for urban flood and runoff control to safeguard the
public and property. The District was formed by the State legisla-
ture in 1969. Although responsible for flood control for urban run-
off events, this District has been reluctant to assume responsibility
for urban runoff water quality.
Presently, no single agency is responsible for regional planning
for water supplies for Denver. However, the Denver Water Board pre-
sently supplies nearly two-thirds of the municipal raw water used in
the region.
The Colorado State government also has an important role in plan-
ning and policy-making which directly effects the Denver region. The
Regional Transportation District (RTD), which was formed by the State
legislature, has the responsibility for improving bus service within
the region and for developing a new fixed line transit system for metro-
politan Denver. The State Division of Highways is responsible for many
areas relating to transportation planning in Colorado and Denver, in-
cluding road improvements and construction.
The Colorado Division of Planning serves as an advisory and
coordinating agency. It was created within the Department of Local
Affairs, to, among other things, prepare planning.
11-68
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"for meeting problems in areas of highways, air
and water pollution, water supplies, sewage dis-
posal, recreation, urban and non-urban growth,
transportation, education, industrial and commer-
cial development and related matters."
In addition, the Colorado Land Use Act established, within the Office
of the Governor, the Colorado Land Use Commission in order to provide
the leadership to encourage planned and orderly land use development.
In a related matter, Governor Lamb issued a policy statement on growth
in Colorado in 1976. Probably the most significant portion of this
policy relevant to this EIS is that relating to future growth. Three
most pertinent objectives are moderating net in-migration into the
state, encouraging economic growth in areas other than the front range,
and the minimizing of urban sprawl. Also, refer to Appendix A which
contains the full text of this State policy statement.
Planning for air quality is the responsibility of the Air Pollution
Control Commission and the Air Pollution Control Division (APCD) of the
Colorado State Health Department. The APCD is in the process of de-
veloping an air quality maintenance plan for the Denver area. This
work will be closely coordinated with other planning agencies through
the policy bodies of these various agencies. Obviously, such coopera-
tion is a necessary prerequisite for developing an implementable air
quality maintenance plan since it requires assumptions as to future
population, land use and transportation modes.
The State Water Quality Control Commission is the central authority
in all matters pertaining to water pollution control in the State and
the Denver region. The Commission sets water quality standards and
classifies waters of the State for various beneficial uses. The Water
Quality Control Division of the Department of Health is the admini-
strative arm for water pollution control activities. Their principal
responsibilities include: State water quality planning, administration
of discharge permits, enforcement of water quality regulations, and
review of applications and plans for new wastewater treatment plants.
11-69
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III. Proposed Projects
and Alternatives
-------
SECTION III
THE PROPOSED PROJECTS AND ALTERNATIVES
PROPOSED PROJECTS
This section of the EIS presents proposed and alternative ap-
proaches that have been examined for meeting regional water quality
goals.
BACKGROUND
This draft EIS has been prepared simultaneously with the draft
Clean Water Plan prepared under Section 208 of the Water Pollution
Control Act Amendments of 1972 (P.L. 92-500). The draft Clean
Water Plan is commonly referred to as the 208 plan, and was prepared
by the Denver Regional Council of Governments, the region's 208 plan-
ing agency. The Clean Water Plan is concerned primarily with non-
point sources of water pollution, and secondarily with point sources.
The draft Clean Water Plan and supporting draft Summary Technical Re-
port are reproduced in the Appendix to this draft EIS. Plans for
controlling point sources of pollution from the region's municipal
wastewater treatment plants are called Facility Plans or 201 Plans,
and are prepared under Section 201 of the Water Pollution Control
Act Amendments of 1972.
The major non-point source of pollution in the Denver area is
urban runoff. The 208 study has identified the effect of urban run-
off for each of the fifteen subbasins on in-stream water quality.
The conclusion reached by the Clean Water Plan is that, even with
adequate point source controls, non-point sources in the form of ur-
ban/agricultural runoff would probably prevent year around achieve-
ment of desired water quality for all of the streams in the metropoli-
tan area, except for the South Platte above Chatfield Dam. A detailed
analysis was not undertaken for the Eastern Plains subbasin by the
208 study. As a result of this conclusion, the 208 study investigated
the feasibility of implementing structural and non-structural control
measures which would yield the desired water quality, stream segment
by stream segment throughout the urban study area.
The major point sources of water pollution in the Denver region
are effluent flows from regional and subregional wastewater treat-
ment plants. Two basic approaches are being considered for control
of these sources. One approach would transport wastewater to a large
regional plant; the other would involve the operation of several sub-
III-l
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regional and local satellite plants. The latter approach is pre-
sently favored by DRCOG because of the greater opportunity for reuse
of the region's wastewater and because it allows local control over water
quality and allocation decisions. This preference is reflected in
the point source recommendations of the 208 plan.
An issue that has not been resolved for point sources is whether
to provide secondary treatment of wastewater, followed by land appli-
cation, or to provide advanced treatment, including denitrification,
with some form of effluent reuse. The selection of either of these
options will depend on costs, local availability of land, water rights,
public opinion, and local water demand. 'Both options, however, are
predicated on the analysis that some form of advanced wastewater treat-
ment will be needed in order to meet existing and/or future water
quality goals.
Alternative and Preferred Non-Point Source Control Strategies
Basically, non-point sources consist of urban and rural storm-
water runoff. The 208 Plan has estimated that non-point source control,
which would result in the achievement of the 1983 goals, would cost
the area approximately 255 million dollars per year amortized over
the 20-year planning period. The conclusion of the 208 study is that
this cost is excessive for the "minor" improvement in water quality
that would be expected.
Of the 255 million dollars for non-point source controls, about
87% would be for structural controls which are designed to collect,
store, treat, and discharge the treated stormwater. Therefore, a non-
structural "program" approach to controlling non-point sources is being
recommended by the 208 Clean Water Program. The goals of this ap-
proach would be to maintain and improve the quality of runoff in the
region by, for example, such typical measures as improved street sweep-
ing services, regulation of domesticated animal wastes, and regula-
tion of lawn fertilizing. As part of this approach, the 208 Plan
recommends that implementation of structural non-point controls be
held in abeyance until specific problems can be pinpointed. The 208
plan suggests that more monitoring of stream water quality is needed
to make this assessment and that such a program should be completed
in several years.
Alternative and Preferred Wastewater Treatment Facility Designs
The following sections summarize the major known features of the
individual facilities being collectively examined in this draft EIS.
The description of each facility also includes a discussion summari-
zing the feasible alternatives from which the preferred design was
selected and stating the reasons why it was considered superior.
III-2
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Planning areas for these facilities are shown on Map J. Table III-
A lists the facilities, their design flows, efflutent standards,
and describes the feasible alternatives based on best available in-
formation.
South Adams County Water and Sanitation District Service Area—
The South Adams County Water and Sanitation District (SACWSD) en-
compasses about 10,000 acres of South Adams County and currently oper-
ates as an independent district. The present facilities consist of
a 2.5-mgd (million gallons per day) plant using primary sedimentation,
followed by trickling filters. The sludge is anerobically digested,
dewatered on drying beds, and disposed of on land. The plant needs
expanding and upgrading if it is to meet future effluent standards
and to handle the service area's projected flow.
Two basic alternatives were considered. One was abandonment of
the present plant, pumping all wastewater to the Metropolitan Denver
Sewage Disposal District plant #1 (MDSDD #1). The other was expan-
sion and upgrading of the current plant to handle future flows. The
latter course was chosen (alternative 4), with phased construction
of a 1.25-mgd expansion in 1978, addition of a 2.5-mgd ammonia removal
step in 1983, and a 1.25-mgd increase in capacity, including ammonia
removal, in 1986. This will provide a total plant capacity of 5.0
mgd by 1986. This plan is considered by the facility planner to be
the most cost-effective and energy-efficient. The plant effluent
would be discharged into the South Platte River,
Englewood/Littleton Advanced Wastewater Treatment Plant—
The cities of Littleton and Englewood have entered into a joint
contract to build a treatment plant to handle the sewage from both
cities. The new plant, now under construction, with a capacity of
20 mgd is located adjacent ot the present Englewood sewage treatment
plant. Ultimate expansion to 38 mgd is planned in 1985. The City
of Littleton is constructing a sanitary interceptor to carry excess
waste from its treatment plant to the existing Englewood plant. The
two existing treatment plants will not be expanded, and all future
flows in excess of the capacities of the existing plants will be
diverted to the joint-use plant. In the future, one or both of the
existing plants may be phased out of service.
Currently a 201 facilities plan is being prepared for advanced
treatment at the joint plant now under construction. The plan will
consider ammonia and chlorine removal by various techniques, and
effects of not adding these facilities. The plan will also consider
whether to upgrade (but not expand) one or both of the existing
plants or whether to phase them out. In considering the various
III-3
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Table III-A. CURRENT FACILITY PLAN ALTERNATIVES
(* indicates plan recommendation)
H
H
h-l
I
Design
flow, Effluent
Facility ngd Standard
South 5.0 BOD: 20 mg/1
Adams SS: 20 mg/1
plant NH -N:
expansion 3.5 ng/1
and Inter- fecal coli-
ceptor forai
severs 200/100 «1
cesidual Clt
0.5 mg/1
Englewood/ 20
Littleton
advanced
wastevater
treatment
plant
South present
Lakewood popula-
plant tion:
expansion 68,000
vs . inter-
ceptor to maximum
Denver* popula-
tion:
80,000
to
85,000
Alternatives Considered
Alt. 1: reglonaliza-
tion with Denver
Metro (MDSDD 11 by
1983; 1.25-mgd acti-
vated sludge plant
In 1977; abandoned
by 1985.
present worth:
$6.7 million
Alt. 1: Chlorine and
ammonia removal fa-
cilities at Littleton
plant, the Englewood
plant and the L/E
plant. Littleton
plant and Englewood
plant to receive a
base-load flow and
all excess to the
L/E plant.
ann. cost: $636,000
Alt. 1: Improve and/
or enlarge existing
treatment plant to
serve only South
Lakewood, Bonvue,
Daniels and part of
Lakewood; parallel
some outfall sewers
within these dis-
tricts. (Existing
plant size) 2.0 to
3.0 bgd).
Alt. 2: primary eedi-
Dentatlon, existing
trickling filters
(2.5 mgd); 1978, add
1.25 mgd activated
sludge, 5.0 mgd dis-
persed floe nitrifi-
cation; 1986, 1.25
mgd activated sludge
sludge drying beds;
disposed to land.
present worth:
$5.65 million
Alt. 2: Chlorine and
ammonia removal facil-
ities at the L/E plant
and the Littleton
plant. Phase out the
Englewood plant. The
Littleton plant to
receive a base-load
flow and all excess
flows to the L/E
plant.
ann. cost: $718,000
Alt. 2: make no im-
provements to exist-
ing plant, but
transport effluent
to MDSDD #1, for fur-
ther treatment.
Alt. 3: primary sedi-
mentation, existing
trickling filters
(2.5 mgd); 1978, add
1.25 mgd rot. biol.
disc (RED) with ni-
trification; 1983,
2.5 mgd RED nitrifi-
cation; 1986, 1.25
mgd RED with nitrifi-
cation; sludge anaer-
obically digested,
drying beds, disposed
to land.
present worth:
$6.2 million
Alt. 3: Chlorine and
ammonia removal facil-
ities at the L/E and
the Englewood plants.
Phase-out the Littleton
plant. The Englewood
plant to receive a
base-load flow and all
excess flows to the
L/E plant.
ann. cost: $649,000
Alt. 3: abandon ex-
isting plant; lay
larger trunk sewer
to connect to Metro
District intercep-
tor line (i.e., all
flows to MDSDD 11
for treatment).
Alt. 4: primary sedi-
mentation, existing
trickling filters
(2.5 mgd); 1978, add
1.25 mgd RED without
nitrification; 1983,
2.5 mgd RED nitrifi-
cation; 1986, 1.25
mgd RED with nitrifi-
cation; sludge anaer-
obically digested,
drying beds, disposed
to land.
present worth:
$6.15 million
Alt. 4: Chlorine and Alt. 5: Consider-
ammonia removal fa- ations and prob-
cilities at the L/E able effects to
plant only. Phase- stream reclassifi-
out the Littleton cation to eliminate
plant and the the need for any
Englewood plant. chlorine and/or
ammonia reduction
facilities.
ann. cost.: $680,000 ann. cost.: $630,000
Alt. 4: Enlarge
existing plant, con-
struct AWT and im-
proved sludge han-
dling facilities;
consider construction
of lines for recy-
cling effluent for
urban Irrigation.
(Plant site 5-6 mgd) .
-------
Table III-A (Continued). CURRENT FACILITY PLAN ALTERNATIVES
Facility
Cherry
Creek
and
Goldsmith
Gulch
Intercep-
tor sever
Lower
South
Platte
treatment
plant and
Intercep-
tor severs
Design
flow, Effluent
mud standard
185
26 BOD: 20 rag/1
(Includ- SS: 20 mg/1
ing 6.0 NH3-N:
SACWSD) 3.0 mg/1
DO! 5 mg/1
Color: 25
JTU: 25
fecal coil-
form:
1,000/100 ml
residual Cl:
0.05 mg/1
Alternatives Considered
Alt. 2: system of
a ewers to carry en-
tire area flow to
Northside plant;
upper half paral-
lels eastern bank
of S. Flatte River,
lower half paral-
lels existing
Delgany main; no
pumping station
required .
present worth:
$25.2 million
Alt. 4* new plant
at 164th Ave. and
S. Flatte River to
treat flow from
Brighton, Lower
Thornton and 1st,
2nd and 3rd creeks;
flow from Upper
Thornton and HWSWSD
pumped to MDSOD 11
(1981 plant: 8.3 mgd.
1990 to MDSDD tls
8.3 ragd, 2000 to
SACWSD; 6 mgd);
SACWSD to remain
Independent; ef-
fluent discharged.
present worth:
$25.1 million
Alt. 3: same as Alt.
2, except sewers
routed to east of
downtown area rather
than parallel to
Cherry Creek outfall
and eastern bank of
S. Flatte River.
present worth:
$26.2 million
Alt. 5: same as Alt.
4, except flow from
Lower Thornton also
pumped to MDSDD il
(1981 plant: 3.7 mgd,
1990 to HDSDD fl:
13.3 mgd); effluent
discharged.
present worth)
$25.2 million
Alt. 4: same as Alt.
2, except flow routed
directly to MDSDD «.
Instead of Northsid*
via Band Creek.
present worth:
$28.5 million
Alt. 14: same as
Alt. 5, except flow
from Lower Thornton
pumped to Big Dry
Creek Treatment
Plant (City of West-
minster); effluent
discharged.
present worth:
$24.4 million
Alt. 5* same as Alt.
2, except capacity
based only on 1985
projected flow (136
mgd); additional fu-
ture capacity pro-
vided by construc-
tion of Cherry Creek
satellite plant and
staged expansion of
plant as required;
plant effluent to be
reused; 1985 design:
8 mgd.
present worth:
$25.9 million
-------
Table III-A (Continued). CURRENT FACILITY PLAN ALTERNATIVES
M
I
Facility
Clear
Creek
sod
Sand
Creek
service
ArCA8
Design
flow, Effluent
Bgd standard
•fc35 BOD: 20 ng/1
SS: 20 mg/1
HH3-N:
3.0 mg/1
DO: 5.0 mg/1
Color: 25
JTU: 25
fecal coli-
form:
1,000/100 nl
residual Cl:
0.05 mg/1
Alt. 1? parallel Alt. 8«: new plant
Clear Creek intercep- near Toungfield St.
tor to transport all and 40th Ave. to
basin flow to HDSDD provide treatment
*1 for treatment. through NH3-N re-
moval for flows from
N. Table Mountain,
Applewood and Pleas-
ant View (air acti-
vated sludge; sludge
anaerobtcolly di-
gested; drying bed;
sold); 1983: 6.56
mgd; effluent for ur-
ban reuse; remainder
transported to HDSDD
11 for treatment.
present worth: present worth:
$22.2 million $28.4 million
Alternatives Considered
Clear Creek
Alt. 10: same as Alt.
8a, except flows from
Golden, Northwest
Lakewood and West ridge
also treated at new
plant (1983: 13 mgd);
effluent for urban
reuse; remainder
transported to MDSDD
tl for treatment.
Note: Golden has pro-
posed its flows be
treated locally, by a
new plant, for reuse.
present worth:
$30.8 million
Sand Creek
30-40
BOD: 20 mg/1
SS: 20 mg/1
NH3-N:
3.0 mg/1
DO: 5.0 mg/1
Color: 25
JTU: 25
fecal coll-
form:
1,000/100 nl
residual Cl:
0.005 mg/1
Alt. 1: parallel
Sand Creek intercep-
tor to transport
flow froB entire ba-
sin to MDSDD tl.
present worth:
$18.7 to 22.0 mil-
lido
Alt. 3? new plant at
existing Aurora plant
site for primary
through advanced
treatment for estab-
lished flow volumes
(air activated sludge;
sludge anaerobically
digested; drying bed;
marketed); effluent
for urban, domestic,
agricultural or indus-
trial reuse, prefer-
ably domestic reuse
in Quincy reservoir;
remainder of flow to
MDSDD tl for treat-
ment.
present worth
$19.8 to 21.5 Bil-
lion
Alt. 4: same as Alt.
3, except all flow
from Sand Creek in-
terceptor treated at
new plant; remainder
of flow to HDSDD tl
for treatment.
present worth:
$22.7 to 25.4 Bil-
lion
-------
Table III-A (Continued). CURRENT FACILITY PLAN ALTERNATIVES
Design
flow,
Facility ngd
Broom- 10
field/
West-
minster
regional
treatment
plant
Metro 185
Denver
Sewage
District
Plant t 1
Effluent
standard
BOD: 20 mg/1
SS: 20 mg/1
NH3-N:
2.5 mg/1
DO: 6.7 mg/1
JTU: 50
Colon 60
fecal coli-
form:
200/100 ml
residual Cl:
0.5 mg/1
Primary alternative
1. conventional pri-
mary settling
2. vertical screen-
ing
Alt. : 1 Treatment
and discharge con-
sideration will be
Riven to various
methods and levels
of ammonia removal
Discharge to the
South Platte
River .
Secondary alternative
1. air activated
sludge
2. oxygen activated
sludge
3. activated bio-
logical filter
4. rotating bio-
logical disc
clarification in cir-
cular clarlflers and
chlorine disinfection
Alt. 2: Land Applic-
ation consideration
will be given to
irriKstlon hiKh— rate
irrigation, overland
flow, and infiltrat-
ion/percolation .
Alternatives Considered
Solids handling This recommendation was made by •
Facilities Plan completed two years
Plan !• being redone.
treatment
2. treat at site:
a. digestion:
air aerobic,
oxygen aerobic.
anaerobic
b. de water ing:
drying beds,
heat and vacuum
filter, vacuum
filter, filter
press, centri-
fuge
c. disposal:
landfill.
incineration
Alt. 3: Treatment & reuse
consideration of domestic
reuse by the Denver Water
for irrigation via
Burlington Dlthc. These
evaluations will also
Involve all pertinent
water rights Issues.
*Plan of study only; recoraended alternative not determined! costs not determined; standards, flow rates not given.
NOTE: The symbol * indicate! th« recommended alternative.
-------
alternatives, the degree of treatment required to meet all projected
flows and effluent limitations will be assessed.
South Lakewood Service Area—
The Lakewood service area encompasses approximately 11,300
acres. The area is extensively developed, having a present popu-
lation of about 68,000 and a maximum projected population of 80,000
to 85,000. The existing treatment plant is operated by the South
Lakewood Sanitation District and currently serves about 37 percent
of the existing population, or 25,000 people. The remainder of the
area flow is transported to and treated by the MDSDD #1 plant.
The facility plan for the area is still in preparation, but
the plan of study has indicated the following alternatives for
meeting future effluent requirements: (1) improve and enlarge the
existing plant to treat flows from the areas currently served, the
rest continuing to go to MDSDD #1 for treatment; (2) continue to
use the existing plant, but transport the effluent to MDSDD #1 for
further treatment; (3) abandon the existing plant, and transport
all flows to MDSDD #1; and (4) enlarge the existing plant, add ad-
vanced treatment and sludge disposal facilities, and either discharge
to the South Platte River through the existing outfall line or use
the plant effluent for irrigation purposes on City lands. Alterna-
tive 4 is presently expected to be recommended.
Cherry Creek and Goldsmith Gulch Service Area—
Improvements to the wastewater collection system for the upper
Cherry Creek service area are being planned and should be considered
in conjunction with the proposed improvements to the Northside
Treatment Plant. This area is within the jurisdiction of MDSDD #1.
Alternatives in the Cherry Creek and Goldsmith Gulch facility
plan considered both the transport of all area flows to the Denver
Northside/MDSDD #1 treatment complex and the transport of some waste to
the Northside complex, with the remainder of the waste going to a
satellite advanced wastewater treatment (AWT) plant to be constructed
in 1985. (Wastewater from the AWT plant would be reclaimed through
domestic, agricultural, or industrial use, whichever is most fea-
sible at the time.) The latter alternative has been selected, al-
ternative 5, with the option of building the satellite plant in
1985 only if it is deemed feasible at the time. In lieu of a sate-
llite plant, additional sewers could be constructed to the North-
side plant. The plan provides maximum flexibility, requires the
lowest initial capital investment, provides for wastewater reuse,
reduces future flow to the Northside/MDSDD #1 complex, and provides
III-6
-------
a shorter distance for wastewater to travel. The satellite plant
would consist of a secondary treatment, followed by tertiary treat-
ment which would be applied only when effluent is discharged into
Cherry Creek. Domestic reuse, industrial reuse, and irrigation
were suggested as possible options.
Lower South Platte Service Area—
The lower South Platte basin occupies the western part of Adams
County and lies generally northeast of metropolitan Denver. It is
divided into nine subareas. The service area is administered by
the Metropolitan Denver Sewage Disposal District No. 1.
The facility plan originally considered 14 alternatives but
narrowed these down to three for final consideration. All three
call for a new wastewater treatment plant to be built at 164th
Avenue and the South Platte River, and for the South Adams plant to
be expanded and to continue operating as a separate district. The
major differences in the three plans concern the amount of the area's
waste to be treated at the new plant, how much is to be pumped to
MDSDD #1, and whether or not any waste can be pumped to the City of
Westminister's treatment plant in the Big Dry Creek Basin for treat-
ment and agricultural use. The selected plan, alternative 4, pro-
vides for treating the greater portion of the area's waste by the
new plant, with the option left open to pump some flow to the West-
minster plant. It was assumed for comparison purposes that the
treatment plant would provide secondary treatment, with ammonia re-
moval, sludge handling by anaerobic digestion, air drying, and
subsequent marketing. Agricultural use was not considered serious-
ly because of its projected cost.
Clear Creek and Sand Creek Service Areas—
The Sand Creek Basin encompasses a large portion of Arapahoe
County, smaller portions of Adams County, and the City and County
of Denver. It is divided in five subbasins, administered by
MDSDD #1.
The facility plan focused on basically two alternatives: Al-
ternative 1 involves transport of all area wastewater flow to MDSDD
#1 for treatment; Alternatives 3 and 4 involve advanced treatment
of varying quantities of flow by a new plant and reuse of the water
for domestic purposes. Since a large portion of the water currently
received by the City of Aurora is "new" western-slope water, a por-
tion of this water can be reused by the City before discharge. This
water would be treated and pumped to the Quincy reservoir, a domes-
tic raw water supply.
III-9
-------
Alternative 3 was selected as the preferred alternative.
This plan provides advanced treatment and reuse of a smaller
portion of wastewater than under Alternative 4, but it is signi-
ficantly less expensive. It has several advantages over Alter-
native 1, providing for reuse and successive use of water, reduc-
ing the amount of sewer construction along Sand Creek, and maximiz-
ing the use of existing facilities. For purposes of comparison,
the new treatment plant was assumed to provide secondary treatment
with ammonia removal, sludge handling by anaerobic digestion, air
drying, and subsequent marketing.
The Clear Creek planning area, which occupies portions of
Jefferson and Adams counties, lies generally northwest of metro-
politan Denver and includes 11 subbasins. It is administered by
the MDSDD # 1. The facility plan evaluated seriously two alterna-
tives, one involving transport of all area wastes to MDSDD #1, the
other involving treatment through ammonia removal of some of the
area flow. On the primary basis of cost, Alternative 1, the
transport of all area wastes to MDSDD #1, was selected.
Broomfield/Westminster Service Area—
This service area encompasses the cities of Broomfield, West-
minster, and portions of Thornton. The City of Northglenn is not
included as it has selected an independent course of action. Ex-
isting facilities include a 3.6-mgd plant operated by the City of
Broomfield and a 1-mgd plant operated by the City of Westminster.
Both plants discharge into Big Dry Creek. The facility plan recom-
mendation shown in Table III-A was rejected and a new plan is in
preparation.
The Westminster plant is currently operating at or near capa-
city, and immediate expansion to 2 mgd is planned, to prevent the
imminent pollution of Big Dry Creek. A new 201 facility plan is
being prepared, to consider further expansion of the plant to ap-
proximately 4.5 to 6.0 mgd. This would provide adequate capacity
to treat flows from Broomfield in excess of 3.6 mgd as well as all
other area flows.
In an effort to thwart the efforts of adjacent cities to con-
demn agricultural water for municipal purposes and to show that
cooperation is superior to condemnation, the Northglenn City Coun-
cil entered into an agreement in 1976 with the Farmers Reservoir
and Irrigation Company Board of Directors which allows Northglenn
to borrow water from Standley Lake, use it for municipal purposes,
collect the sewage, treat the sewage, and store the winter flows
for summer irrigation by farmers. Urban drainage, lawn irrigation
return flow, deep well water and South Platte alluvial well water
111-10
-------
will also be collected, treated if required, and transported to a
storage facility in such quantities as to return all of the borrowed
water to the farmers plus provide a 10 percent "bonus".
Subsequently, a contract was signed in 1977 between the City
of Westminster and the Farmer's High Line Canal Company for an ex-
change of water rights. Under this agreement, secondarily treated
effluent will be discharged to the canal and used for irrigation
of crops, and an equivalent amount of raw water will be diverted
from the canal to Standley Lake, which is the city's municipal water
supply (Reference 972).
Expansion of Metropolitan Denver Sewage Disposal District
Plant No. 1—
Currently, expansion of MDSDD #1 to include additional secondary
treatment is being completed, which will increase the treatment capacity
to 170 mgd. Ammonia removal facilities will have to be added to
this plant by 1983 in order to meet effluent standards at that time.
The addition of ammonia removal capability should increase the
plant capacity to approximately 190 mgd, and phased additions will
provide a capacity of 205 to 220 mgd by the year 2000.
The facility plan for additional treatment has not yet been
prepared; however, the plan will consider three basic alternatives:
treatment and discharge to the South Platte River, land application
of effluent, and treatment and reuse. Under the treatment and dis-
charge alternative, various methods of ammonia removal will be con-
sidered. Under the land application alternative, methods to be con-
sidered will include irrigation, high-rate irrigation, overland
flow, and infiltration/percolation. Under the treatment and reuse
alternative, consideration should be given to domestic reuse by
the Denver Water Board and to successive use for irrigation via
Burlington Ditch, including considerations of water rights issues.
The course likely to be followed is the treatment and discharge al-
ternative as it will involve the fewest legal and technical prob-
lems and will, in all probability- be relatively less costly com-
pared to the other alternatives.
208's Recommended Plan for Municipal Wastewater Treatment Plants
Table III-B identifies the costs and effluent levels for the
major facilities in the Denver metropolitan area, as estimated by
the DRCOG 208 program. The costs are total capital and operation and
maintenance costs for all aspects of municipal wastewater control
through the year 2000.
III-ll
-------
Table III-B
Recommended Plan for Municipal Wastewater Treatment Plants
Facility
Littleton/Englewood
South Lakewood
MDSDD//1
South Adams County
Brighton
Glendale
Sand Creek
Golden
Big Dry Creek
Louisville
Lafayette
Erie
Boulder
Longmont
Mountains
Plains
Cost1
(Millions)
48.1
6.8
97.1
7.5
4.1
1.8
16.0
9.9
15.3
4.2
6.9
2.6
24.2
6.2
5.0
1.3
Effluent Requirement
BOD
5
5
20
20
20
5
20
5
5
5
5
5
5
20
20
20
NH3-N
1
1
18
18
18
1
18
1
0~32
1
1
1
1
18
9/153
15
N03-NH
1
1
-
-
-
1
-
1
15
1
1
1
1
-
-
-
(mg/1)
PO.-P
4
8
8
8
8
8
8
8
0.3
8
8
8
8
8
8
8
8
1
These present worth costs reflect capital for facilities and inter-
ceptors and operation and maintenance of the facilities, interceptors,
and collection systems through the year 2000.
2
Full-time nitrification with part-time breakpoint chlorination for
total ammonia removal.
3
Bear Creek requires nitrification to 9 mg/1 of NH3~N, but all other
mountain and plains areas are 15 mg/1 NHL-N as given in the Mountain
and Eastern Plains Water Quality Study.
4
Dash indicates that nitrate will not be a problem unless discharges
are excessive.
Source: "Technical Report Summary" DRCOG March 1977
111-12
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The effluent levels describe what can be reasonably expected
for each community's discharge after proper treatment to achieve
compliance with the 208's proposed stream classifications and cri-
teria. These limitations do not reflect the minimum requirements
for each parameter which would eventually be the basis for issuing
NPDES discharge permits. For example, the 5 mg/1 of BOD specified
for Boulder is the level one would expect in their effluent after
meeting phosphate and nitrate requirements.
EIS ALTERNATIVES - POINT SOURCES
In keeping with the regional overview of this draft EIS, three
basic strategies were assembled from the various alternatives ex-
amined in completed and ongoing facility planning efforts. One of
these strategies, no-action, is required by the National Environ-
mental Policy Act. Each of these alternative strategies will be
assessed in subsequent sections of this report for their environ-
mental impacts. Mitigating measures to reduce or eliminate impacts
will also be evaluated. It is expected that the information in this
draft EIS, plus public review and input, will change and evolve one
of the strategies into a course of action which will minimize environ-
mental impacts and maximize environmental benefits. The three basic
facility plan strategies addressed in this draft EIS are termed LOCAL,
REGIONAL, and NO ACTION. They are summarized in Table III-C.
The Local Alternative
This alternative generally consists of the recommended alter-
natives of the completed Facility Plans, and the alternatives ex-
amining expansion and/or upgrading of treatment levels for existing
wastewater treatment plants for facility plans now in progress. The
exception is that the recommended alternative for the Clear Creek
service area, parallel interceptor to MDSDD #1 plant, is replaced
by the alternative (8a) calling for a new plant serving North Table
Mountain, Applewood, and Pleasant View with the remainder served by
interceptors to the MDSDD #1 plant. Alternative 4 of the ongoing
South Lakewood facility planning effort is assumed for the local Al-
ternative. Figure III-A illustrates this alternative. This alter-
native close resembles the recommendations of the Clean Water Plan
(208 Plan).
The Regional Alternative
This alternative generally consists of alternatives examined in
the completed and in-progress Facility Plans which call for centra-
lized treatment at the Northside/MDSDD #1 treatment complex. Figure
III-B illustrates this alternative.
111-13
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Table III- C. SUMMARY OF ALTERNATIVES
Service area
Local alternative
Regional alternative
No-action alternative
South MODS
Eoglevood/Llttleton
South LaVevood
Cherry Creek/
Goldsmith Culeh
Lover South ?latte
Clear/Sand creeks
Blooafield/
Westminster
MDSDD fl
Maintain existing plant, add 1.25 mgd
without nitrification 1978, 2.5 mgd
nitrification in 1983, and final 1.25
capacity addition with nitrification
in 1986 for a total capacity of 5 mgd
Addition of aumonla and chlorine re-
moval for 20 ngd capacity by 1979.
Further expansion of Joint plant to
total capacity with AWT to 38 mgd in
1983
Enlarge existing plant, construct
AVT and Improved sludge handling fac-
ilities; capacity expanded from 2
ngd to 5-6 mgd. Some effluent reuse
System of interceptors to expected
1985 flow fro.T. upper Cherry Creek to
NorthslcWMDSDD i\ complex. Provi-
sion for AWT satellite plant in 1985
New plant for flows from Brighton,
lower Thornton, 1st, 2nd and 3rd
creeks. Remainder of area flows to
MDSDD 11 and South Adama County
Water and Sanitary District.
New plant with 6.5 mgd capacity in
1983 on Clear Creek. AWT for reu«e,
Additional flows to >BSDD II
New plant at existing Aurora plant
site for 30-40 mgd with reuse, Re-
mainder of flows to MDSDD (1
Expansion of existing Big Dry Creek
plant to 8 mgd by 1985 with land ap-
plication/agriculture reuse.
Addition of ammonia removal for to-
tal plant capacity of 190 tagd by
1983. Optln for reuse
Add 1.25 »gd activated sludge capacity
in 1977, abandon plant In 1985, all
flowa to MDSDD fl
Same ai local alternative except flowa
over 20 mgd transported to HDSSD fl
Abandon existing plant and transport
all flowa to Northside/MDSSD II couple*
Sana aa local alternative except addi-
tional interceptors added in 1985 in
lieu of AWT Cherry Creek satellite
plant
All flowa transported to MDSDD #1
Parallel Clear Creek interceptor to
transport all basin flow to MDSDD II
for treatment.
Parallel Sand Creek Interceptor to
transport flov from entire basin to
MDSDD (1. Abandon existing Aurora
plant
Maintain existing planta with excese
flow to MDSDD fl
Plant expansion with ammonia re-
moval for total capacity by 1990 of
260-270 mgd.
Add 1.25 ngd activated aludge and
5 mgd dispersed floe nitrifica-
tion capacity 1978, final 1.25
mgd activated sludge added in
1985
Addition of ammonia and chlorine
removal delayed till 1980. Ulti-
mate expansion to 38 ogd delayed
to 1986.
Maintain existing plant, and ser-
vice area, transport effluent to
Northaide/MDSDD fl complex
Same as local alternative except
construction of interceptors de-
layed two years, plans for satel-
lite plant abandoned
Same a* local alternative except
delayed four years.
Same at regional alternative ex-
cept delayed three year*
Same a* regional alternative ex-
cept delayed three years
Expansion of existing Big Dry
Creek plant to 5 cgd, expansion
of Bloomfield plant by 3 Egd,
lower Thornton to MDSDD fl
Addition of antonit recovel ft*
cilitiea delayed until 1985
-------
FIGURE III-A
LOWER S. PLATTE
1981 8.7 mgd - 1991 11.4 mgd
BIG DRY
CREEK
CLEAR
CREEK
1981 3.0 mgd
1995 9.6 mgd
ELD/WESTMINSTER//. SOUTH ADAMS
D 2.5 mgd
1978 3.75 mgd
// 1986 5.0 mgd
DISCHARGE TO
BIG DRY CREEK
SAND CREEK INT.
AURORA
CLEAR CREEK
INTERCEPTOR
NORTHSIDE
DELGANY MAIN
1983 6.5 mgd
1991 8.0 mgd
O
"SOUTH LAKEWOOD
*2.0 mgd
\CHERRY CREEK OUTFALL \
PLATTE RIVER II
INTERCEPTOR
WEST AND
SOUTHWEST
_JAIN
g ENGLEWOOD
12.0 mgd
LITTLETON
4.5 mgd
SAND
CREEK
GOLDSMITH \^ \a 1985 8 mgd
GULCH \\ \ 1995 16 mgd
OUTFALL CHERRY CREEK
977 20 mgd
1983 38 mgd
EXISTING MAJOR SEWERS
PROPOSED MAJOR SEWERS
EXISTING MAJOR TREATMENT PLANTS
PROPOSED MAJOR TREATMENT PLANTS
SOUTH PLATTE RIVER
SCHEMATIC OF
LOCAL ALTERNATIVE
111-15
-------
FIGURE III-B
BIG DRY
CREEK
SOUTH ADAMS
ABANDON BY 1985
MDSSD#1 1990 280-290 mgd
EFFLUENT TO SOUTH PLATTE
WITH SOME REUSE
CLEAR CREEK
INTERCEPTOR
AURORA PLANT TO BE
I SAND CREEK
SOUTH LAKEWO_OD____~-— jj
»- — ~"~~
TO BE ABANDONED
'\ CHERRY CREEK OUTFALL \
PLATTE RIVER II jj
INTERCEPTOR '
WEST AND
SOUTHWEST
MAIN
GOLDSMITH^ \\
OUTFALL
CLEAR
CREEK
SAND
CREEK
CHERRY CREEK
a ENGLEWOOD
1976 20 mgd
I (TO BE MAINTAINED)
• LITTLETON
SOUTH PLATTE RIVER
EXISTING MAJOR SEWERS
PROPOSED MAJOR SEWERS
EXISTING MAJOR TREATMENT PLANTS
PROPOSED MAJOR TREATMENT PLANTS
SCHEMATIC OF
REGIONAL ALTERNATIVE
111-16
-------
The No-Action Alternative
This alternative assumes that no EPA grant funds for design and
construction would be received by local agencies, As water quality
standards would still have to be met, this alternative assumes that
wastewater treatment facilities would still have to be constructed.
Financing would be borne entirely by local agencies, primarily the
City and County of Denver and MDSDD #1, probably by revenue bonds
retired by user charges and connection fees. Some costs may be
met through other revenue sources.
ALTERNATIVES TO STREAM DISCHARGE
Land application of wastewater effluent*may be used with ex-
isting irrigation or by development of new irrigation on cropland,
rangeland.or forested areas and parks. In general two basic ap-
proaches are involved: ownership and operation of a land treatment
system, or distribution of effluent to an existing agricultural or
other operation. The latter system is a more realistic possibility
for the eastern Colorado area. Excessive costs, water rights prob-
lems, and the complications of entering the agricultural market have
made wastewater treatment agencies reluctant to enter the land appli-
cation field.
Systems involving reuse are being looked upon with increasing
favor by Colorado communities. Some communities view wastewater
reuse as a potential means of increasing their domestic water sup-
plies, and/or as a means of avoiding the condemnation of agricultural
water rights. Generally only those communities owning non-tributary
(West Slope diversion) water are legally entitled to "reuse" water
for their own purposes. Other potential systems however have the
capability of increasing water supplies for municipalities using
South Platte tributary water.
EPA's chief concern is, of course, protection and enhancement
of water quality. If any of the potential reuse or land applica-
tion systems have positive water quality benefits that would result
in attainment of relevant stream standards, such systems may be
eligible for construction grant funding.
There are a number of ways wastewater reuse systems could oper-
ate. Most reuse systems proposed or in operation use one or a com-
bination of three basic approaches. These are:
Effluent is the term used to describe the discharge of treated
wastewater.
111-17
-------
Direct Reuse—Where a municipality is discharging wastewater
to a stream and a user downstream is diverting waters for agricul-
ture from the stream, it is possible for the municipality to ful-
fill the agricultural users needs by direct discharge of waste-
water effluent to an agricultural supply ditch. The raw water nor-
mally diverted for agricultural use could be left in stream. This
fact and the removal of wastewater effluent nutrients from the
stream could result in significant water quality advantages. This
approach does not result in an increased municipal water supply,
and could only be implemented with imported western slope water
unless a water exchange agreement for South Platte water rights
was in force. This is because rights to imported water include
rights to reuse. South Platte water must be returned to the stream.
Water Exchange—Upstream agricultural rights to South Platte
or tributary water may be exchanged for direct discharges to agri-
cultural users holding upstream rights. In this way, agricultural
users still receive the same quantity of water, it is just "used"
before they get it. This approach can be used to increase munici-
pal water supplies without condeming (seizing) agricultural water
rights for municipal use.
Recycle—This system would involve having a municipality reuse its
own treated wastewater effluent as part of its expanded potable water
supply. Such a recycling system could substitute for water that
would have to be developed from other sources for population growth;
however, very high levels of treatment would be required.
Other potential reuse schemes could involve the use of treated
wastewater for industry, urban irrigation, etc. These latter uses
would be possible only if the water were non-tributary, since ad-
ditional uses could consume some of the supply. These latter sy-
stems are subsets of the "recycling" system.
All of the potential reuse schemes discussed are under con-
sideration in the metropolitan Denver area. The water exchange
and reuse arrangements are currently used at times at the Metro
plant with the adjacent Burlington Ditch, Westminster and North-
glenn have proposed systems of the water-exchange type for increas-
ing water supply type. Recycling is being seriously considered by
the Denver Water Board and Aurora. Reuse by urban irrigation is
now practiced by Aurora and South Lakewood, and Aurora is also con-
sidering the possibility of industrial reuse of effluent.
111-18
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CLEAN WATER PLAN MANAGEMENT ALTERNATIVES
Section 208 of PL 92-500 requires that any plan prepared
under its authority recommend management agencies which would
be responsible for plan implementation. In response to this re-
quirement DRCOG in its draft Clean Water Plan evaluated six water
quality "management" alternatives-for point sources. They are:
1. Continuation of the existing system.
2. Basin or service area approach.
3. Regional Service Authority.
4. Metropolitan Council.
5. State oriented approach.
6. Single-purpose agency approach.
For non-point sources, the 208 plan considered existing institu-
tions only.
Point Sources
DRCOG is recommending for municipal point sources that
all districts and municipal treatment agencies as of July 1, 1977,
be designated management agencies. Exceptions to this are the
cities of Longmont and Lyons, the Niwot Sanitation District which
will be included within the St. Vrain-Left Hand Conservancy Dis-
trict, and the Highline Park and Water and Santitation District
which will be represented by the Supervisory Group of the Little-
ton/Englewood Management agency. Single purpose collector agencies
and treatment agencies with wastewater flows under 1 million gal-
lons per day (mgd) are not being recommended for designation by
the 208 plan.
The DRCOG is concerned that the 34 agencies proposed for desig-
nation, coordinate their future wastewater activities, Therefore,
the 208 plan is recommending that a Water Quality Advisory Com-
mittee be formed with representatives from each management agency
and six others representing two other existing DRCOG water related
committees. The primary function of this coordinating group would
be to set priorities for wastewater treatment projects within the
208 area.
The 208 study has identified short term and long term goals
for future consolidation of these management agencies. The short
term goals are: (1) to form immediately within each subbasin, a
cooperative organization which consists of all the designated
management agencies within that basin, and (2) at the end of five
years after approval of the initial 208 plan, to have only one
111-19
-------
designated management agency per subbasin. The long term goal
is to establish a form of metropolitan governance which has
enforcement and veto power as well as responsibility for muni-
cipal wastewater management.
Non Point Sources
The 20g plan recommends that no agencies be designated, at this
time, to have management responsibilities for the water quality
aspects of non-point sources. This recommendation is based on the
following factors: (1) non-point source problems were identified
on a regional basis, but specific sources were not identified; (2)
the logical agency for urban stormwater control, the Urban Drain-
age and Flood Control District (UD&FCD) does not have statutory
authority for water quality; and (3), the UD&FCD was reluctant to
assume responsibility for the water quality of urban runoff. DRCOG
is suggesting that designation of nonpoint source management agencies
be postponed pending further analysis of the specific nonpoint prob-
lems within the 208 study area.
111-20
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IV. Probable
Environmental
Impacts
-------
SECTION IV
PROBABLE ENVIRONMENTAL IMPACTS
The future of the Denver region will be shaped by the growth
the region experiences in population, production of good and ser-
vices, and supportive facilities. The expansion of wastewater
collection and treatment capacity affects the amount and distri-
bution of growth in a region by increasing the supply of developable
land. Because growth may generate significant secondary impacts in
terms of the natural and social environment, this chapter begins with
an examination of the region's likely future growth as the basis for
subsequent evaluation of probable environmental impacts of the 201
facilities plan, and the Clean Water Program.
SOCIO-ECONOMIC IMPACTS
Regional Population and Economic Impacts
Sources of regional growth—
The growth of a region starts with the creation of jobs ser-
ving markets outside of the region. Agriculture, manufacturing and
military activity form part of Denver's export economy (basic demand)
As people move into the region, jobs serving the local market are
created in activities such as retail trade, entertainment and con-
struction (local demand). The number and diversity of firms serving
the local market grow with the increase in basic demand and in popu-
lation. The purchase of locally produced goods and services leads
to continued production using local labor, land and capital. This
results in additional locally produced goods and services. The cre-
ation of jobs in basic demand sectors provides the base for popula-
tion growth, but population growth provides the labor force to fill
the jobs and creates additional jobs serving the local market. Thus,
population growth and economic growth become interdependent.
The relationship between job growth and economic growth is sub-
ject to a number of influences. One of these is imperfect labor mo-
bility. Inadequate information about changing economic conditions
results in a lag in response which may differ among age and skill
groups in the labor force: the more mobile, highly educated seg-
ments of the labor force respond to such information more rapidly,
while in-migration of the less educated and/or less skilled may be
slower to taper off. Some in-migration may occur even in the face
of adverse local economic conditions because the newcomer may be
coming from a location where economic conditions are even worse.
Interregional commuting may also affect migration. Finally, there
may be a substantial component of migration which is not predict-
IV-1
-------
able on the basis of economic factors, as groups such as retired
persons and students move for reasons unrelated to employment.
For those groups and others, the relative attractiveness of the
region may also be an incentive to move there. Less desirable
living environments are less likely to have a "growth problem."
Economic impacts of growth—
The economic effects of growth are expressed in terms of the
increase in the production of goods and services that provide
people with satisfaction and with the increases in jobs and income
that are created in the production of these goods and services.
Fiscal impacts - changes in the cost and quality of public goods
and services - are a component of overall economic effects and are
discussed separately below. Unlike fiscal or physical impacts,
which are often confined to limited spatial areas or political
jurisdictions, the effects of growth on the economy cannot ade-
quately be analyzed in terms of local impact because growth in
one locality will have economic effects that ripple outward through
the region.
The benefits derived from the increase in the production of
goods and services as a result of growth affect different interests
in society depending upon their role within the regional economy.
Table IV-A summarizes many of these effects. Consumers receive sa-
tisfaction from the increased choice, quantity, type and price of
goods and services such as agricultural products, housing, shopping
and convenience goods items, personal services, repair services,
entertainment and cultural functions and recreational functions.
Labor force members benefit from the increase in jobs to produce
these goods and services and from the incomes thereby generated.
Investors experience increased income benefits as a result of the
production process, including incomes from the land values that are
created. The profit potential of industrial and commercial in-
terests benefits from economies of scale, advantages of speciali-
zation, development of readily available markets within short dis-
tances and increases in the ease of communication.
While each type of participant is able to realize a different
type of benefit, any one person or entity in society is likely to
be able to realize several different types of economic benefits de-
pending upon the roles in which he/she participates. The same is
true of the costs of economic growth which arise as a result of the
increasing specialization, complexity, size and scale of an urban
area. People and firms become more dependent on each other since
there are more of them in one area, they are more specialized, and
they see each other and must interact more often and with more other
people and firms. Choice creates opportunities, but may also in-
IV-2
-------
Table IV-A.
INCIDENCE OF THE ECONOMIC IMPACTS OF GROWTH GENERATED BY
LNCREASECS IN THE PRODUCTION OF GOODS AND SERVICES
Housing consumer
Consumers of goods
and services other
than housing
Labor force
members
Capital investors
and landowners
Industrial and
commercial interests
and firms
Low income
households
Greater number of housing
options of different types
and prices,
Improved quality of housing
units.
Increased choice of goods
and services available in
terms of quantity, type
and price.
Increase in job opportuni-
ties. Growth in real in-
comes .
Growth of incomes.
Increases in profit through
increases in productivity
and lower costs resulting
from: economies of scale,
advantages of specializa-
tion, plentiful labor supply,
readily available markets
and ease of communication.
Labor force members: Job
opportunities and real in-
come growth. Greater choice
in housing and consumer
goods.
Retired; Slower increase in
housing cost due to expand-
ing supply. Increased value
of local investments (if any).
Increase in congestion as
a result of the increase
in size and complexity of
area, Increase in depen-
dence on neighbors and other
members of society.
Difficulty in identifying
consumer options,
Difficulty in identifying
consumer options, Less
independence.
Increase in competition
for jobs. Increase in
need for specialized train-
ing and experience. In-
crease in congestion and
travel distances.
Higher risks from increased
competition, increased
opecialization and more
rapid technological change.
Higher risks and increases
in failures as a result of
more competition, difficulty
in discerning market pre-
ference and sizes, increased
specialization, and more
rapid technological change.
Same costs as identified
above for consumers and
labor force members,
Same costs as identified
above for consumers.
Source: Gruen Gruen & Associates
IV-3
-------
crease risk. These negative aspects of economic growth are also
summarized in Table IV-A.
Evaluating the economic costs and benefits of growth—
It has been argued that, at some point, the economic advan-
tages of growth are offset by economic disadvantages. But, de-
spite the intuitive evidence that large metropolises are unplea-
sant, noisy, congested and timewasting, economic research has yet
to find that nay city in the United States has reached the point
at which, in the aggregate, marginal economic costs exceed margi-
nal economic benefits (Reference 1000).
However, economic and population growth can assume an in-
finite variety of forms, the noneconomical impacts of which may
significantly differ. Policy approaches available to cope with
these noneconomic impacts include planning to accommodate antici-
pated growth in a manner so as to minimize such costs and adoption
of "no growth" or "slow growth" strategies. It should be pointed
out that these nonaccommodationist approaches cannot guarantee
either the maintenance of present standards of living or environ-
mental quality: "no growth" does not mean "no change." Imple-
mentation of a no growth or slow growth objective limits or pre-
cludes the conomic benefits to be derived from expansion and may
alter the structure of the local or regional economy and the eco-
nomic opportunities available to local residents.* If economic
advantages of growth are not to be curtailed or eliminated, then
public concern about the effects of growth should be directed to-
ward identifying' and mitigating potentially deleterious impacts
while guiding development toward the attainment of regional land
use patterns which are environmentally sound.
A
By whatever means achieved, a restriction on the rate of population
growth will have an impact on the number and type of employment op-
portunities (the demand for labor) and on the composition and size
of the labor force (the supply of labor). A reduction in the growth
rate will impact industries differentially depending on whether their
level of operation is more closely related to the total size of the
economy (for example, retail trade) or to the rate of economic ex-
pansion (on which the construction sector is primarily dependent).
Cost of no-growth to individuals therefore dependent on their invest-
ments and the economic sector(s) on which their livelihoods depend.
The reduced new job opportunities discourage in-migration and en-
courage out-migration, and out-migration normally affects the more
highly skilled first, as discussed previously.
IV-4
-------
Future economic growth in the Denver region—
The Denver Regional Council of Governments (DRCOG) has fore-
cast that employment in the five-county region will more than double
during the period from 1970 to 2000, with total employment reach-
ing a level of 1.305 million by the end of the century. Employment
is expected to grow most rapidly during the initial portion of the
forecast period (increasing 2.7 percent per year between 1975 and
1980) and level off toward the end of the period (increasing 1.8
percent per year between 1990 and 2000) (Reference 259).
The DRCOG forecast is based on projections of historic (1958-
1975) total employment and employment by industry group; the results
of the trend projection were adjusted in line with observations of
the previous (195801965) effects of national growth, industry mix
and regional influence on employment growth. Adjustments also were
made to insure compatibility between employment and population pro-
jections. The industry-by-industry forecast is presented in Table
IV-B; the table also includes a projection of the labor force par-
ticipation rate.
The DRCOG forecast shows declining agricultural employment,
which is consistent with agricultural land conversion estimates pre-
sented elsewhere in this chapter. All other sectors show significant
increases, with the service sector leading the way. Overall, the
economy will continue to be oriented more toward the production of
services than the production of goods, as was discussed in Section
II. The sectors of mining, construction and manufacturing are fore-
cast to decline slightly in terms of their collective share of total
nonagricultural jobs, while increases in the service and FIRE (fi-
nance, insurance and real estate) sectors will come primarily from
reductions in the shares of manufacturing and TCU (transportation,
communications and utilitites).
The current DRCOG forecast has not been allocated to counties.
Earlier employment forecasting by DRCOG in connection with the Joint
Regional Planning Program did consider distribution, and Table IV-
C presents an estimate of what the distribution of forecast employ-
ment might be, given the county shares projected in the course of
that analysis (Reference 262). Figure IV-A shows the changing shares
of county employment and population in 1976 and 2000. While Adams
and Boulder counties retain their relative shares of the total, and
Arapahoe and Jefferson counties increase their share significant-
ly, Denver's share is forecast to decline substantially.
IV-5
-------
Table IV-B. SECTOR EMPLOYMENT FORECAST FOR THE
DENVER REGION, 1975-2000
Industry
Sector
Agriculture
Mining
Construction
Manufacturing
Transportation,
Communications
and Utilities (TCU)
H
f Trade
Finance, Insurance
and Real Estate
(FIRE)
Services
Government
(including military)
1975
6.7
7.8
42.5
94.7
42.1
161.6
44.9
143.4
124.4
Jobs in
1980
6.5
8.3
48.1
107.1
45.8
185.5
52.1
167.0
124.8
Thousands
1985
6.4
8.9
53.6
118.2
49.8
206.8
58.4
188.0
158.6
o /. o -i
2000
5.9
11.0
71.5
154.6
62.9
275.6
78.2
260.6
210.2
iion c
% Change
1975-2000
-11.9
+41.0
+68.2
+63.3
+49.4
+70.5
$74.2
+81.7
+69.0
J.CO O
% of Total
Nonagricultural
Employment , - 2000
1.0
6.4
13.7
5.6
24.5
7.0
23.2
18.7
TOTAL
Labor Force Partici-
pation Rate (total
employment •;• total
population)
Source:Ref. 259
-------
M
-Table IV-C. EMPLOYMENT PROJECTIONS FOR
THE FIVE-COUNTY DENVER REGION
County
Adams
Arapahoe
Boulder
Denver
Jefferson
Total
Current (1975)
Employment
72,200
68,400
60,400
371,400
95,700
668,100
DRCOG
1980
85,400
86,100
71,600
407,600
112,500
763,200
Employment
1985
94,500
106,500
78,300
435,100
134,300
848,700
Forecast
2000
125,900
175,800
101,200
513,600
214,000
1,130,500
Source: Totals from Ref. 259; distribution to counties by Gruen Gruen
-t- Associates based on Ref. 262.
-------
EMPLOYMENT
POPULATION
1975
2000
1975
2000
<
00
1 - ADAMS
2 - ARAPAHOE
3 - BOULDER
4 - DENVER
5 - JEFFERSON
SOURCE: EMPLOYMENT ESTIMATES FROM TABLE IV-C
AND POPULATION ESTIMATES FROM REF 231.
REGIONAL EMPLOYMENT
AND
POPULATION BY COUNTY
-------
Future population growth in the Denver region—
A year 2000 population forecast of 2.35 million has been
adopted by DRCOG as the basis of all its planning activities. This
"policy population forecast" incorporates elements both of regional
policy and of forecasting. The antecedent of the forecasting ele-
ment is an earlier forecast by DRCOG of 2.175 million in the year
2000; this forecast was based on (1) the continuation of the 1972
rate of net national increase (8.5 persons per 1,000 population
annually) and (2) a gradual tapering off of net in-migration from
the high levels (42,000 per year) of 1970-1973. (In the 1975-1980
period, net in-migration is forecast to be 15,700 annually, which
was the 1960's rate; by 1980-2000, a further reduction to 15,100
annually is forecast, which was the average during the 1940-1970
period.)
This DRCOG staff forecast was reviewed by the Council, with
Council members bringing to the consideration of this issue infor-
mation from their local jurisdictions. After extensive discussion,
the Council of Governments revised the staff forecast upward by
175,000 resulting in the 2.35 million total. The southeastern part
of Jefferson County received the bulk of this addition. In January
1973 the amended total was adopted by DRCOG as regional policy.
The net natural increase rates experienced in the last four
years are lower than those underlying the DRCOG forecast. Net natural
increase declined from 8.5 per 1,000 in 1972 to 6.3 per 1,000 in
1974. Net in-migration has dropped from a 1972 high of 61,400 to
about 16,000 per year (preliminary data reported in Reference 993).
(The addition of 175,000 to the original forecast results in an im-
plicit change in the forecast of in-migration, which would have to
be 22,000 persons per year if the year 2000 forecast of 2.35 million
is to be attained (Reference 993). Whether the net natural increase
rate will stabilize at a lower level, or the net in-migration will
continue to decline, is not known. However, the DRCOG forecast can
be seen as describing a reasonable upper limit to regional popula-
tion growth.
Community Services and Facilities
The increase in population and economic activity forecast to take
place by the year 2000 has implications for the provision of public
services and facilities through the region. Among the services which
will face increased demand are sewage collection and treatment; water
supply fire and police protection; garbage collection and disposal;
roads and other transportation services and public works projects;
education; general governmental services; and parks and recreation.
One study of growth in the Denver area found that, to serve an addi-
tional 1,000 persons, an additional 12 acres of public institutional
IV-9
-------
uses and parks, 13 acres of streets, seven school classrooms, 150,000
gallons of water per day, two firemen and three policemen would have
to be supplied (Reference 307).
The added community services and facilities will result in an
increase in the costs of the government agencies which supply them.
At the same time, new development will increase the local tax base.
The fiscal impact of growth is individual to the service-providing
entities; the regional fiscal impact of growth is only the aggregate
of the local impacts, a. point receiving further discussion in the
next section. The investigation of the impacts of growth on public
service requirements in the Denver region is part of the study pro-
gram of the Denver Metro Environmental Analysis commissioned by the
U.S. Department of Housing and Urban Development; this study has
not attempted to quantify these impacts.
Costs, Financing and Fiscal Impacts
The major fiscal issue related to grow in that of whether the
provision of public services to new users will affect the quality or
quantity of services to existing users and of whether existing costs
will be affected. The often-heard question of whether growth pays
for itself is usually directed to the concern that the provision of
public services to new users could increase the costs to all those
paying taxes and user charges without increasing or improving the
service outputs to existing users. For example, the Boulder Valley
Comprehensive Plan establishes a policy that "new growth should bear
the major expense of self-created needs for community services and
facilities to the immediate neighborhood" (Reference 1012).
As shown in Table IV-D, there are circumstances in which the
costs of providing additional public services exceed the revenue gener-
ated by the new users and new taxpayers so that the net result of fis-
cal impact is an increase in costs to all users and taxpayers within
the relevant public service jurisdiction.
It is not possible to generalize as to whether new development
will have a positive or negative fiscal impact on existing service
users and taxpayers. The fiscal outcome is determined by five vari-
ables:
. the make-up of the existing population and development;
. the type of development experienced (scale, type and value
of land used);
. the state of capital facilities in the relevant service
districts at the time the demand for service increases
(i.e., the presence or absence of unused capacity);
IV-10
-------
Table IV-D. INCIDENCE OF THE FISCAL IMPACTS OF GROWTH
GENERATED BY AN INCREASE IN THE DEMAND FOR PUBLIC SERVICES
Interest of Actor
Benefit
Cost
Recipients of additional public
service outputs (such as new
residents).
Existing taxpayers and existing
recipients of public services
in jurisdictions providing the
additional public service
outputs.
Local municipalities and
special purpose districts
providing the additional
service outputs.
Local municipalities and
special purpose districts
other than those providing
the additional public
service outputs.
Public service out-
puts.
Reduced taxes and
user charges if new
users generate a
net surplus of
revenue over costs .
A net fiscal surplus
if revenues exceed
costs.
Avoidance of service
system expansion (if
efficient levels of
operation have been
reached).
Existing taxpayers and
existing recipients of public
services in jurisdiction other
than those providing the
additional public service outputs
Public taxes and
user charges.
Increased taxes
and user charges
if new users
generate a net
deficit of costs
a
over revenues .
A net fiscal
deficit if
costs exceed
revenues.
Failure to
achieve efficient
levels of
operation (if
now operating
at lower than
optimum rate
of output).
Indirect benefits or costs
depending upon which of the
two conditions above apply.
aCircumstances under which these conditions would be experienced are
discussed in the text.
Source: Gruen Gruen + Associates
IV-11
-------
the laws and policies concerning the types of taxes that
are used to pay for the various kinds of public services;
and
the policies that the relevant service districts apply
to the setting of tap fees and user charges.
COST CONSIDERATIONS
There are two factors which largely determine the impacts of
growth on the cost of a particular public service. There are (1)
the proportion of total costs represented by fixed or capital costs,
and (2) the excess capacity of existing facilities,
A sewage treatment plant provides a service where a high pro-
portion of total costs are fixed. Therefore, if the plant has ex-
cess capacity, ther per unit cost (dollars per unit of wastewater
treated) would decrease with population growth because fixed costs
are spread over a larger base. However, if existing facilities are
operating at capacity, new facilities would have to be built to ac-
commodate additional population and per unit costs would go up.
For services with low fixed cost compared to total cost, an
increase in demand is unlikely to increase per unit costs. Police
protection and schools are examples of these kind of services. The
per unit costs of these services are more affected by the quality
of service demanded by a community than by population growth.
Revenue considerations—
The net fiscal impact depends on the particular nature of the
user charges and tax rates for generating service revenues as well
as on the relationship between the revenues generated and the ap-
plicable set of costs, determined as discussed above. Many local
public services are supported primarily by property taxes. While
it is true that higher valued properties can generate higher tax
revenues than can those of lower value, there is no property value
level at which, as a rule of thumb, one could say that a net fis-
cal surplus will or will not result. It is the present and future
mix of land uses - in terms of type and value - that determines
net fiscal impact. There are differences among land use categories
in terms of their demand for services and the revenues they generate,
Industrial and commercial uses, for example, do not directly gene-
rate demand for educational services although they generate revenue
to the school districts providing those services. Residential uses,
on the other hand, do generate education costs; whether they also
generate enough revenues to offset those costs depends on the value
of the development and the number of school-age children it houses.
IV-12
-------
Net fiscal impacts and land use planning—
The type of growth a particular community experiences will in-
fluence its future service requirements and costs, and will deter-
mine its revenues as well. When viewed from a regional perspective,
growth per se is likely to bring a mix of uses, including resi-
dential uses which provide housing for the workers in the in-
dustries and commercial establishments. "Less fiscally desirable"
uses must go somewhere within the region if the "more fiscally de-
sirable" ones are to continue to exist there. But, though a bal-
ance of uses may exist in the region as a whole, a local community
may have a higher than average share of either type of development,
depending on the community's location, market assets and the his-
toric land use mix. An individual community may attempt to in-
fluence its fiscal condition by -attracting "high value" development
(such as major retail or industrial uses) and discouraging "low
value" development (such as inexpensive housing with high demand
for public education). This kind of fiscal rivalry can result in
less efficient regional land use patterns.
On a local area basis, land use patterns can be planned to mini-
mize the costs of providing government services. For example, higher
density residential development may have lower per-unit road require-
ments and thus lower unit costs for roads; this results in lower unit
costs for street lighting and street maintenance.
However, even where land use patterns are designed to minimize
costs, this does not guarantee that revenues will exceed costs or,
more important, that development in that location would be the least
costly. Certainly that development would not be least costly in the
short run if it requires the construction of new facilities while ex-
cess capacity for services exists elsewhere in the region at a loca-
tion which the new use would accept.
While fiscal impacts are of importance to taxpayers and to public
service users, public decision makers would be aware that fiscal im-
pact is only part of a project's economic impact. Fiscal impact analy-
sis considers only those costs and benefits which appear as cash flow-
ing in and out of a particular local government treasury. It omits
privately received costs and benefits as well as the interdependencies
between types of land uses and among different public service juris-
dictions. It also says nothing about the economic desirability of
land uses. Thus, the question "does growth pay for itself" cannot
be answered from the rather narrow perspective of fiscal impacts a-
lone. A development with a negative fiscal impact may still be de-
sirable, and a development which promises to be a local fiscal asset
may nevertheless be undesirable. There are other impacts against
which the fiscal impacts must be balance.
IV-13
-------
Impacts of Wastewater System Costs—
The costs Denver communities will pay for wastewater
facilities described elsewhere in this report are summarized in
Table IV-E.
The 208 Plan has estimated a total capital cost to the five
county region of 70 million dollars through 1985 to obtain the
desired water quality levels specified in the Plan. The figure was
calculated using an 8% inflation factor for the years 1977-1982.
Beyond 1982 an inflation factor was not used. Through year 2000 an
additional 40 million dollars of capital expenditures are expected
for treatment system expansion and upgrading. The present worth
cost for both capital and 0 & M for collection systems, through the
year 2000 is 257 million dollars for the 208's recommended plan for
municipal wastewater treatment plants. The 208's cost estimate
to meet the 1983 goals is 292 million dollars annually of which
37 million dollars per year is for municipal wastewater control.
Some portion of these costs will pay for expansion of wastewater
treatment capacity, and these are the costs associated with growth.
The remainder of the costs will finance changes in waste treatment
operations to result in a treated waste product less damaging to
the environment. This represents an increase in service quality
(though it is being undertaken more in response to federal regulation
than to local demand) and is therefore appropriately borne by native
and new resident alike. The facility plans have not broken costs
down by these two categories—system expansion and upgrading of
treatment levels. The additional information on growth accommodation
and facility plan objectives presented in Table IV-E provides a basis
for making this type of determination. It must be kept in mind that
other projects such as the Denver Northside and MDSSD No. 1
wastewater treatment complex expansion and the new Littleton/
Englewood regional plant are under construction. From the information
presented in Table IV-E, it can be estimated that about one-half
the total estimated cost for the next five to seven years is for
growth accommodation.
The 208 study has estimated that approximately 65 percent of the
total capital cost through the year 2000 are growth induced costs.
In total dollars this would amount to about $200 million out of the
$310 million projected for capital improvements excluding collection
system, operation and maintenance costs.
No per capita cost estimates are presented in the eight 201
facilities plans for their respective service areas. The 208 Plan
has projected an average per capita cost of about $150 based on the
year 1985 cost estimate to achieve desired water quality levels
IV-14
-------
Table IV-E. ESTIMATED AGGREGATE CAPITAL COSTS OF WASTEWATER FACILITIES
ALTERNATIVES (MILLIONS OF 1976 DOLLARS THROUGH 1983
1
I—'
Ol
P] anning Area
South Adams County
Englewood/Littleton
South Lakewood
Cherry Creek-
Goldsmith Gulch
Clear and Sand Creeks
Westminster/Bloomfield
Lower South Platte
MDSSD No. 1
Total Estimated Cost
local Agency Share
EPA Grant Funds
Construction Employment
Person-years
Local
4
5
11
24
33
11
17
14
119
30
89
4,100
Regional
6
3
6
24
38
5
13
17
112
28
84
3,860
No-Action
4
2
5
22
30
7
14
14
98 c
98
0
3,380a
% of Growth to Facility Plan Objectives
TQOO
Accommodated Capacity Improved Treatment
Less than 1% X
24% a X
2.5% X
13% X
23% X X
7% X
7.5% X
b X
The Littleton/Englewood satellite plant now under construction is expected to accomodate growth till 1983 (20 mgd).
Another capacity expansion would be required, and evaluated in an EIS, at that time.
b. KDSSD No. 1 would treat, under the local alternative, partial flows from Clear and Sand Creeks, flows from Cherry
Creek/Goldsmith Gulch after primary treatment at the Denver Northside Plant, as well as flows from other areas
not covered by listed planning areas. Capacity expansion now under construction. Further additions to capacity would
be to accomodate growth.
c. An estimated $10 million additional would be expended after 1983 with about 345 person-years construction employment.
-------
and the 1985 projected population of 1.8 million people.
The data presented in Table IV-E cover estimated costs of waste-
water prjects in six service areas. The South Adams County Water
and Sanitation District's current facilities plan calls for an
initial capital improvement program involving approximately $3
million, of which most is eligible for federal funding (Reference
509). The plan presumes that 75 percent of the cost will be fed-
erally funded, with the local portion to be financed by the sale
of bonds. The district meets all requirements for federal grant
funds.
Englewood and Littleton have already received federal funds
for construction of a jointly operated plant to provide treatment
up to the secondary level and will probably apply for grants for
future improvements to that plant. The cities are financially sound
and appear to meet all requirements for federal grant-funding.
The City and County of Denver proposes additonal inter-
ceptors in the Cherry Creek area. The only source of long-term
debt financing available to City and County of Denver is revenue
bonds of the Wastewater management Division. The sale of revenue
bonds must be approved by the City Council, as must any increases
in user charges (Reference 225).
The Metropolitan Denver Sanitary Disposal District No. 1
(MDSDD #1) proposes future expansion of its main plant and upgraded
treatment to be financed in part by state and federal grants and
in part by the sale of revenue bonds (Reference 318). For MDSDD #1
to qualify for federal grant funds, all the user districts must con-
form to federal grant standards; apparently not all conform at pre-
sent. This problem has caused delays in allocation of federal grant
money in the past (Reference 225), and MDSDD //I does not have any
control over the means by which member districts raise revenues. The
District itself was authorized to issue some $30 million in revenue
bonds, of which $20 million had been sold by 1973 for capital im-
provements currently being completed. This means that about an ad-
ditional $10 million worth of bonds can be issued without further
voter approval. Beyond that amount, MDSDD // 1 would have to obtain
voter approval for a subsequent bond issue. It has been reported
that there may be some resistance by district users to any further
service charges or additional revenue bonds in the future (Reference
225). Given the likelihood of voter resistance to substantially in-
creased charges, if federal grant funds are not forthcoming, it is
unlikely that MDSDD #1 would be able to raise sufficient capital to
pay for much more construction.
IV-16
-------
Future treatment plan expansion by the Cities of Broomfield
Westminster is proposed to be financed in part by Federal grants.
Both cities have received federal funds in the past, and both seem
to meet requirements for future federal funding. However, if grant
money were not made available, the cities would probably raise sub-
stantial capital by sale of more revenue bonds. To what extent each
city would be willing and able to sell these bonds is not known.
The South Lakewood Sanitation District (SLSD) intends to apply
for a federal grant for expansion of its treatment plant and upgrad-
ing of treatment to meet July 1977, standards. A facility plan is
currently being prepared for these improvements. In case the SLSD's
reliance on property tax revenue proves unacceptable for federal
funding purposes, discontinuation of ad valorem taxation would be
considered.
Estimates of effects of the costs of proposed facilities on
user charges, tap fees, etc., are not available. Increases will oc-
cur, their magnitude is not as yet known. Some estimates can be made
as to whether current resident or new residents will bear the ma-
jority of the capital costs of new facilities. Over a twenty-five
year period, and a net growth rate of about two percent, 55-60 percent
of the cost of new facilities would be borne by new residents. At
a higher growth rate of four percent, the cost percentage increases
to a range of 65-70 percent.
LAND USE CHANGE TO THE YEAR 2000
Between 1960 and 1970, the Denver region experienced an ac-
celeration in suburbanization as the City and County of Denver be-
came less dominant in terms of population concentration, though it
continued to be the region's main job center. In the late 1960's,
and especially in the first part of the 1970's, employment has also
become more widely dispersed through the region, with the City and
County of Denver accounting for a declining share of regional employ-
ment. These changes have been accompanied by changes in land use
patterns, with the suburban counties (Adams, Arapahoe, Boulder and
Jefferson) experiencing increases in developed acreages and losses
in agricultural and vacant acreage. These kinds of changes are
unique neither to the 1960's nor to Denver: the pattern is common
throughout the country, and it has every likelihood of continuing
in the Denver region through the end of the century.
Future Land Use Change
In tabulating land use data, eight use categories have been
established, and DRCOG has project acreage in each use by census
tract as a function of future population and employment. This
tabulation, aggregated by county is presented in Table IV-F.
IV-17
-------
Table IV-F. COUNTY LAND USE SUMMARY, 19070 and 2000
f
t—'
00
County
and
Year
Adams
1970
2000
Change
t
Arapshoe
1970
2000
Change
Boulder
1970
2000
Change
Denver
1970
2000
Change
Jefferson
1970
2000
Change
Total
1970
2000
Change
Residential
Singler
family
9,249
20,547
11,298
3,498
18,456
9,958
9,427
17,000
7,573
21,505
23,167
1,662
15,020
26,684
11,664
63,699
105,854
42,155
Multi-
family
888
2,481
1,593
519
1,532
1,013
946
2,358
1,412
3,296
4,254
958
838
2,300
1,462
6,487
12,925
6,438
Inductrial,
Transportation
Commercial Services Communications
956
1,825
869
595
1,498
903
892
1,697
805
1,975
3,019
1,044
1,174
1,983
809
5,592
10,022
4,430
145
306
161
254
527
273
153
332
179
720
788
63
966
1,146
130
2,238
3,099
861
12,268
16,392
4,124
7,115
12,589
5,474
8,251
13,471
5,220
28,687
32,761
4,074
15,430
20,348
4,918
71,751
95,561
23,810
Parks and
Recreation
1,151
2,439
1,288
2,951
4,054
1,103
6,726
6,919
193
6,102
6,578
476
1,754
3,074
1,320
18,684
23,064
4,380
Agriculture,
Public and Undevelopable
Semi-Public and Other Vacant Total
18,591
19,878
1,287
4,662
7,128
2,466
1,956
2,967
1,011
4,382
5,088
706
5,928
6,352
424
35,519
41,413
S.894
103,292
82,672
-20,620
66,169
44,979
-21,190
135,949
119,556
-16,393
25,336
16,348
-8,988
93,011
72,234
-20,777
423,757
335,789
-87,968
146,540
90,763
164,300
92,003
134,121
627,727
Includes streets
Excludes portions of these counties lying outside Denver metropolitan region as defined by DRCOG (Reference 261).
Source: Acreage for 1970 from Reference 205 and for 2000 from Reference 261; figures for both years aggregated on the
basis of 1970 census tracts as described by DRCOG (Mugler, pers. comm., February 10, 1977).
-------
In reviewing the land use projections, the reader should keep
several factors in mind, First, the data does not cover the five
counties in their entirety, but only the portions which form part
of the Denver metropolitan area. Thus, eastern Adams and Arapahoe
and Western Boulder Counties have not been included in the tabula-
tion. Second, the boundary delineating the Denver metropolitan area
for the purpose of land use tabulation was changed by DRCOG after
the 1960-1970 tabulation. The redefinition resulted in the exclusion
from the study area of large blocks of land in Adams, Arapahoe and
Boulder counties. In Table IV-F, the figures for 1970 have been re-
duced by appropriate amounts in the relevant categories (generally
agricultural, undevelopable and other vacant) so that figures for
1970 and 2000 cover the same area, but the total acreage figures dif-
fer from those in Table II-F. Finally, the land use projections of
CRCOG are from the fourth-cycle runs of the EMPIRIC land use fore-
casting model, which preceded the adoption of subarea population al-
locations. To the extent the adopted population allocations (which
in some cases are still in dispute) differ from the population
figures utilized in the computer projections, the year 2000 land
use projections. Notwithstanding this limitation, however, much
can be learned from the land use projections about the future pat-
tern of land development in the Denver region.
All categories of developed land show substantial acreage in-
creases over the 30-year period. The largest percentage increase is
in multi-family residential acreage, which is projected to double by
the year 2000. Single-family residential acreage will increase by
about two-thirds, and commercial acreage by almost 80 percent. Land
use in all other categories is projected to increase by at least 15
percent with the exception of undeveloped (the category headed agri-
culture, undevelopable and other vacant), which is projected to de-
cline by about 21 percent.
Regional Development Patterns
The date presented in Table IV-G offers another way to consider
future land use change in the Denver region: the percentage of total
regional land in a given use category represented by each county's
land in that category is listed for both 1970 and 2000. These data
offer an indication of changes in the roles played by the counties
in the regional context. The last row shows the percentage of land
in each county which was classified as developed in the years 1970
and 2000. The most striking change between 1970 and 2000 is the in-
crease in the percentage of developed land. In Adams, Arapahoe and
Jefferson counties, the degree of urbanization in 2000 as indicated by
this measure will exceed that of Denver (36.9 percent in 1970). Only
Boulder County is projected to retain a comparatively rural develop-
IV-19
-------
TABLE IV-G. PERCENTAGE DISTRIBUTION OF LAND BY USE CATEGORY, 1970 and 2000
Total Land
by Land Use
Adams Arapahoe Boulder Denver Jefferson Category
Land use category 1970 2000 1970 2000 1970 2OOO 197O 7fW) 1Q7fl 2000 1970 2000
M
<
K5
0
Residential 14. 4a 19.4 12.8 16.8 14.8 16.3 35.3 23.1 22.6 11,2 11.2
Commercial and Service 14.1 16.2 10.8 15.4 13.3 15.5 34.4 29.0 27.3 23.8 1.2
Industrial, Transportation,
Communications 17.1 17.1 9.9 13.2 11.5 14.1 40.0 34.3 21.5 21.3 11.4
Parks, Recreation, Public
and semi-public 36.4 34.6 14.0 17.3 16.0 15.3 19.3 18.1 14.2 14.6 8.6
Agriculture, Undevelopable,
Other Vacant 24.4 24.6 15.6 13.4 35.6 6.0 6.0 4.9 21.9 21.5 67.5
% of Land Developed*5 28.7 41.9 23.8 46.0 23.0 36.9 36.9 42.0 29.3 43.9 29.5
18.9
2.1
15.2
10.3
53.5
42.8
b.
'Represents county share of regional total for specified land use.
Includes all categories except (1) parks and recreation and (2) agricultural, undevelopable and other vacant, and
represents percentage of land developed in each county.
Source: Table IV-F.
-------
ment pattern, with less than 23 percent of its land developed.
Even though Boulder is projected to lose 16 thousand acres of
undeveloped land to development over the 30-year period, it will
have a slightly higher proportion of the region's undeveloped
land in 2000 (35.6 percent) than it had in 1970 (32.1 percent).
In the year 2000, the City and County of Denver will have a
reduced share of regional developed land in all categories, as
shown in Table IV-G; Denver's actual acreage increases, shown in
Table IV-F, are small compared to those of othe other counties.
Jefferson County will become more "suburban" than it was in 1970:
residential use will rise by over 80 percent, while land used for
employment activities (commercial, services, industiral, trans-
portation and communications) is projected to grow only 34 per-
cent.
Future land use is hsown on Map I. This future land use map
was developed by DRCOG, and was based upon population and land use
computer projections which have since been superceded as pre-
viously discussed. Map I and Figure IV-B, nevertheless are use-
ful in illustrating where future growth is expected to occur. Map
I should be compared to Map H, and Figure IV-B should be compared
to Map B. Map I incorporates certain planning policies which dimi-
nishes its relationship to the real world. As an example, the
future land use shown excludes floodplains and streamside areas
from development that is clearly known and shown to currently ex-
ist on Map H of current land use. Thus Map I show not expected
land use, but desired land use given certain development policies.
The projections imply some changes in the density of new de-
velopment over the 30-year period. In 1970, there were about 17
persons per acre of land in residential use; in 2000, the projec-
tions indicate about 19 persons per acre. This means that new de-
velopment would be somewhat more dense than residential development
in 1970, with about 23 persons per acre being the average density
of new development. Employment uses are also projected to be more
densely developed in the future, rising from about 0.7 employees
per acre of employment land (which includes commercial, services,
industrial, transportation and communications) to about one em-
ployee per acre in 2000. (These estimates understate actual em-
ployee density because street acreage figures are included in em-
ployment land use. However, that does not affect the direction
of change.
The projections of land in park and recreation use indicate
an increase of over 4 million acres by the year 2000, an increase of
23 percent over the 1970 acreage. However, residential development
and population growth are projected to exceed that rate of increase.
IV-21
-------
IV-22
-------
BOULDER CO (NOM-URBANT
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RAPAHOE CO:
ARAPAHOE GO. URBAN
DOiGLAS CO;
RBAN
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ROXBOROUGH PARK
CD
-------
This means that park acreage per capita is projected to decline by
35 percent, from 15.2 acres per capita to 9.8 acres per capita, be-
tween 1970 and 2000. Although regional open space particularly out-
side the urban areas will be ample, opportunities for active recre-
ation in the urban areas will be significantly diminished. Even with-
out an increase in recreational demand, recreation areas will be more
intensely used and degraded.
Regional Planning Issues
Land use patterns and environmental quality are intimately re-
lated. The magnitude, location, rate and spatial distribution of new
development has important effects on the provision of public and pri-
vate services, on environmental pollution and on the preservation of
stable ecosystems. Elsewhere in this report the impacts of Denver's
future growth on the natural environment (air quality, water quality,
ecosystems and production of food and fiber) have been described. In
this section, the efforts of local and regional agencies to guide de-
velopment so as to minimize its adverse environmental effects are re-
viewed. State policies were enumerated in early 1976 by Governor Lamb
and are reproduced in Appendix A. The adopted planning policies of
the Denver Regional Council of Governments are also included in their
entirety in Appendix A. Within the context of these policies, pos~
sible steps to improve the effectiveness of local and regional plan-
ning are discussed, particularly with regard to wastewater facilities
planning„
Efficiency of Future Development Patterns
Recent literature in planning and regional science has reported
on a number of studies of the relationship between the spatial con-
figuration of land development and its environmental consequences.
These studies typically have found that major land uses have dif-
ferent environmental effects, depending on the pattern of development,
and that a pattern of land development which includes dense concen-
trations of mutually supportive, interacting land uses offers impor-
tant advantages not offered by dispersed development patterns.
The environmental effects of densely concentrated activity are
often readily apparent. The demand for utilities and energy at a site
of concentrated activity is high; traffic volumes result in congestion
noise, and concentrated emission; high percentages of impervious sur-
faces result in microclimatic changes, reductions in groundwater re-
charge capabilities and possible increased problems in accommodating
stormwater runoff. However, these direct effects may be the same
whether the uses are concentrated or free-standing; the concentration
of activities draws our attention to these impacts but does not neces-
sarily increase the magnitude of impacts. In fact, the indirect ef-
fects of concentration may result in superior environmental impacts,
IV-2 5
-------
both in reducing environmental degradation below that which would re-
sult from dispersed patterns of development and in providing improved
economic opportunities. Beneficial effects of concentrating land uses
in "activity centers" include (1) expansion of consumer choice (by
providing desirable residential locations for those to whom high den-
sity living is appealing), (2) increasing potential income to firms
and individuals (due to gains in efficiency in communication and ex-
change of goods made possible by proximate locations of activities)
and (3) reduction in the indirect effects of development on the en-
vironment (by encouraging multipurpose trips, and by making walking
and collective forms of transportation reasonable alternatives to the
automobile).
The activity center concept is a key element in the year 2000
plan for the Denver region, and a number of areas have been designated
as activity centers or corridors; these are listed in Table IV-H.
These areas are not yet fully developed (compare current population
and employment to year 2000 population and employment), but the de-
velopment of a complex interaction of densely concentrated land uses
at these sites, supportive of higher density living and public trans-
portation service, is the objective.
The objective of encouraging a more efficient land use pattern
by encouraging activity center development faces a number of impedi-
ments. First, the local jurisdictions with direct land use planning
responsibility implement it unevenly. Arapahoe County is an example
of one jurisdiction which plans to work toward high density levels
along designated travel corridors, in'part in the hope that rail rapid
transit service will eventually be provided (higher density develop-
ment may indeed be a precondition for it). Other communities recog-
nize advantages in higher density housing that are economic as well
as environmental: lower land costs per unit put the higher density
unit in the reach of more households; smaller units are appropriate
in a period of declining household size and declining real incomes;
densely concentrated development has (typically) lower public service
costs per unit. But proposals for dense residential developments
often meet public opposition, with blockage of views, interruption of
scenic corridors and changes in community character given as reasons
for public objections to high density development. With the majority,
especially of the suburban public, lukewarm to the concept at best,
it is not surprising that most planners in the region report that the
bulk of future residential development will be low density and single—
amily ("the market preference of the Denver region," according to a
Westminster planner) with overall residential densities declining by
the year 2000 as discussed in the preceding section.
A second factor working against the effectiveness of the ac-
tivity center as a planning tool is the increasing dispersal of in-
dustrial employment. Recent history suggests that isolated sites
have a significant appeal to those making site-selection decisions
IV-26
-------
for^major industrial facilities. Examples of industrial-location
decisions fitting this pattern include Storage Technology Corpora-
tions (Louisville), Western Electric (Westminster), Michelin (Little-
ton) and Johns-Manville (Jefferson County). The Johns-Man^ille loca-
tion has received considerable publicity, and is an excellent demon-
stration of the role of corporate image in location decisions. The
firm's former chief executive officer-the man who selected the Ken-
Caryl Ranch as the site for the J-M facility-described his decision
in these terms; "A company's headquarters is its signature. I wanted
a new signature for J-M". (Reference 1018). Image, provision for ex-
pansion space, desirable local characteristic such as lower taxes,
lower land prices, more lenient development controls - these factors
may all play a role in the selection of isolated sites by major em-
ployers and may reduce the incentive for firms to locate in activity
centers.
A third factor which may be weakening the activity center plan-
ning strategy is the decision not to fund mass transit by the Urban
Mass Transit Administration. Mass transit is not a precondition to
the success of an activity center's policy; however, the coordination
of land use planning policy with mass transit might have resulted in
local zoning and planning patterns more strongly reinforcing existing
activity centers along the proposed mass transit corridor. With hopes
for rail mass transit dashed, there is a loss of incentive to encour-
age high density uses - residential and commercial - in the travel
corridor (which would have linked together a number of the designated
activity centers).
A fourth factor which favors the dispersal of economic activity
throughout the region is competition among communities for property
tax revenues. Fiscal rivalry weakens the regional perspective in land
use decisions. The Denver Chamber of Commerce objected to Michelin's
decision to locate along the southern edge of Littleton rather than at
a site closer to the residential areas where most Michelin workers will
probably live (Payne, personal communications). Of course, the cities
of the Denver region cannot be faulted for pursuing their fiscal self-
interest in trying to attract industry to locations within their peri-
meters, but local dependence on property tax revenues represents a
significant institutional impediment to the implementation of regional
land use policies based on nonfiscal-environmental and social welfare-
criteria.
Population Growth—
As discussed in Section II, apolicy population forecast for the
Denver region has been adopted by the Denver Regional Council of Govern-
ments (DRCOG) which is expected to serve as the basis for the planning
of regional facilities throughout the five-county metropolitan area.
DRCOG has allocated a year 2000 population of 2.35 million persons to
geographic units called urban service areas, which generally correspond
to local government planning areas. These service areas are shown in
Figure II-B, and the population allocations are given in Table IV-ft,
IV-2 7
-------
TABLE IV-H. REGIONAL SUBAREA POPULATION ALLOCATION BY SERVICE AREA
ro
oo
Service Area
Mountain
Boulder Co Mtn
Evergreen*
Jefferson Co Mtn
Lyons*
Nederland*
Plains
Bennett*
Box, Elder (Ad)
Box Elder (Ar)
Bycrs*
Deer Trail*
East Plains (Ad)
East Plains (Ar)
Strasburg*
Valley
Adams Co (Uninc)
Adams Co (Urban)
Arap Co (Uninc)
Arap Co (Urban)
Arvada
Aurora
Boulder City
Current
1975
29,600
5,900
7,800
14,200
1,000
700
4,400
900
400
400
400
400
200
700
1,000
1,439,800
10,500
62,500
700
35,900
80,600
121,700
92,200
Boulder Co (E Uninc) 13,300
Bow Mar
Brighton
Broomfield
1,100
12,900
16,400
Short Term
1985
40,000
6,700
12,000
18,700
1,600
1,100
6,800
1,700
700
500
700
400
600
700
1,500
1,755,700
14,200
71,400
900
39,900
94,800
157,000
106,700
17,300
1,300
18,000
29,700
Long Term
2000
55,500
7.900
16,800
26,800
2,500
1,500
9,900
2,300
1,100
600
1,000
400
100
1,400
3,000
2,284,600
14,800
83,100
1,200
79,300
117,400
228,700
130,100
24,700
1,300
25,000
44,500
Service Area
Valley (Cont'd)
Cherry Hills Village
Columbine Valley
Commerce City
Denver
Edgewater
Englewood
Erie**
Federal Heights
Glendale
Golden
Greenwood Village
Jefferson (A-P)***
Jefferson (SE Urban)
Jefferson (Uninc)
Lafayette
Lakewood
Lakeside
Littleton
Longmont
Louisville
Morrison*
Mountain View
Northglenn
Sheridan
Superior
Thornton
Westminster
Wheat Ridge
5-County Region
Current
1975
5.400
600
18,600
532,300
5,500
35,900
100
7.600
3,700
14,500
3,500
9,500
21,200
200
5.800
123,000
****
33,500
34,200
3,700
500
800
31,500
6,000
300
27,600
31,600
34,300
1,473,800
Short Term
1985
8,300
600
19,500
566,100
5,600
40,900
300
9,900
8,700
18,600
5,200
11,600
68,200
6,000
10,200
163,700
****
38,000
46,300
10,000
600
800
36,700
8,100
400
39,500
40,700
40,000
1,802,500
Long Term
2000
10,700
600
20,000
646,700
5,900
45,900
800
12,900
8,700
26,000
10,000
15,200
137,900
12,000
14,000
213,600
****
47,300
67,400
13,600
800
800
38,600
13,200
500
65,500
58,900
47,000
2,350.000
*Community Service Area
**Alloc,ition for part in Boulder County only.
***A-P - Applewood-Pleasantview.
****Less than 50.
-------
Local agency forecasts were one source of information to
DRCOG's allocation process. These forecasts vary widely in methods
and assumptions. A number of the local agencies have expressed
the view that DRCOG ignored their work and have questioned DRCOG's
allocation approach, which allocates shares of regional growth to
counties and allocates the county shares among subareas within
the counties. Local planners feel this approach has often dis-
regarded the demand for development in their jurisdictions and
their capability of providing services and facilities supportive
of new development. DRCOG's communications with local agencies
have stressed that local area forecasts must take into account
uncertainties with regard to the future availability of wastewater
treatment and how these services would be financed.
Although the majority of the local jurisdictions agreed to
DRCOG's allocation, a few did not. Even the provision of a per-
missable latitude of 15 percent between the DRCOG allocation and
the local forecasts was not enough to accommodate the discrepancies.
The allocations for Arvada, Aurora, Boulder, Broomfield, Lakewood,
Longmont, southeast Jefferson County, Thornton and Westminster
service areas were still in dispute between the local agencies and
DRCOG. In general, those disagreeing with DRCOG's allocation repre-
sent potential high-growth areas, and the local agency projections
exceed those of DRCOG:
In all of these areas, high short-tern building rates
are projected, and local policy encourages rapid growth.
In the 1975-1980 period, the local total projected increase
for these areas is 189,300 and represents a combined annual
growth rate of 5.2 percent compared to a rate of 2.3 percent
for regional forecast staging. The regional subarea popula-
tion allocation to these growth areas for the same period is
115,300. (Reference 231)
Disparities between regional and local forecasts are of con-
siderable concern to local governments because local agency appli-
cations for federal funds are subject to DRCOG review. The re-
gional council could, at least in theory, determine the size of
the grant or whether a given project would be funded. Local agen-
cies believe that, if they attempt to obtain federal funds for
wastewater treatment facilities sized to serve a planning period
population in excess of that indicated in DRCOG's allocation, they
may be denied funds or the amount of their grant might be reduced.
Thus, a difference in future population estimates is of importance
both to local agencies and to DRCOG. In order to resolve remaining
differences, a Cooperative Forecasting Program Task Force was es-
tablished which included members of local jurisdictions and region-
al agencies. This group was charged with the development of a
IV-2 9
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methodology and set of procedures for use in the preparation of
local population forecasts, which would be applied both by DRCOG
and the local agencies. This work was completed in March 1977.
Several of the proposed wastewater treatment porjects fall
within areas whose future populations are in dispute. The Broom-
field/Westminster area, for example, differs sharply with DRCOG
on what the future population of the subregion will be: the local
forecast for the two-city area is 135,350 (Broomfield, 62,000;
Westminster, 73,300) while DRCOG's allocation is 103,400. The lo-
cal forecast exceeds DRCOG's by about 24 percent. The same is true
for the Lakewood urban service area (Reference 231). As the sani-
tary district boundaries do not correspond with the boundaries of
urban service areas, the extent of disagreement between the local
projections and the regional forecasts for the areas to be served
by new wastewater facilities is difficult to determine.
Impact of wastewater facilities on land use—
Major investment in public facilities frequently serves to
encourage growth, primarily by opening up land for development.
The growth-shaping effects of sewers have been noted in a number
of studies (References 1002 and 258) although most case study work
has focused on interceptors rather than on wastewater treatment
facilities. Such facilities influence an area's growth potential
wherever new development is required to be sewered, which is the
case in most areas of the Denver metropolitan region.
The lack of wastewater treatment capacity in any one area may
limit growth for that area, but, viewed from a regional perspective,
lack of service capacity in one area often diverts growth else-
where. Growth will go where facilities are available to serve it,
as a local building industry representative states (Wyckoff, per-
sonal communication, 28 December 1976).
Growth projections for the 201 facility planning areas are
given in Table IV-I. The Littleton and Englewood planning area
will experience nearly the highest growth rate and is projected
to capture a full 24 percent of projected regional growth. Only
the Lower South Platte area will experience a higher growth rate.
See Map J for the location of those planning areas. Generally,
all of the planning areas except for South Lakewood and South
Adams County will each have a significant share of future region-
al growth.
IV-30
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Table IV-I. POPULATION GROWTH FORECASTS FOR FACILITY PLANNING AREAS
M
to
1— '
Facility Planning Area
South Adams County
Englewood and Littleton
South Lakewood
Cherry Creek and
Goldsmith Gulch
Lower South Platte
Clear Creek
Sand Creek
Westminster and
Broomf ield
Planning Areas Total0
Population,
1975
27
141
100
259b
44
198
82
55b
906
«
Thousands
1985
29
217
111
294b
72
246
120
80b
1,169
2000
29
344
121
370b
107
305
170
113b
1,559
Growth Rate
1975-1985
Less than 1%
4.4%
1.0%
1.3%
5.0%
2.2%
3,9%
3.8%
3.6%
% of Total
Regional Growth
to 2000
Less than 1%
24%
2.5%
13%
7.5%
12.5%
10.5%
7.0%
77%
a. Based on facility plan projections except as noted, rounded to nearest thousand.
b. Based on DRCOG projections, facility plans based on DRCOG projections not complete.
c. MDSSD No. 1 includes Cherry Creek/Goldsmith Gulch, Clear and Sand Creek, and flows from Denver Northside plant
and its inclusion would largely duplicate enumerated projects,
-------
Viewing investments in public facilities as having a greater
influence on the spatial distribution of growth than on the amount
of growth suggests that decisions on whether or not to provide ur-
ban services should be viewed in terms of the chain of events they
set in motion beyond the service are. Thus, a decision not to
serve one area with expanded treatment capacity should take into
consideration pressures on the treatment capacity and sewage systems
in other areas.
CONVERSION OF AGRICULTURAL LANDS
The "conversion of agricultural land" is the name given to
the process which results in a change in the use of land from agri-
cultural to urban. This process may be direct and immediate: au-
tumn's cornfield may be spring's subdivision; or it may be lengthy:
orchards may be replaced gradually by row crops, and row crops by
idle land, over a period of years before construction for urban uses
begins. In the meantime, the land may have passed through several
successive owners, from the active farm owner to a farm lessor to an
owner/real estate investor to a developer. Whatever the length of
time involved and the route taken, the outcome generally is the
same: once farm land is converted to urban use, its reconversion to
agricultural use is, under normal circumstances, impractical. This
section discusses why conversion of agricultural land takes place
and why this form of land use change is of environmental concern.
It then addresses this issue in the Denver context and discusses his-
torical and potential future conversion of agricultural land.
Causes of Agricultural Land Conversion
Farming is an economic activity. It supplies food and fiber
products traded in local, national and international markets and
provides a livelihood to farmers and farm workers. Obvious to those
in the business of agriculture, this point must be made plain if we
are to understand why land is taken out of agricultural use and what
kinds of planning and institutional reforms would be needed to affect
this process.
The farmer's principal raw material is land. Finding farm land
at an acceptable cost is essential if a farmer is to stay in business.
By "acceptable" is meant a cost at which the farmer makes a suffi-
cient return to prevent him for diverting his assets to some other
kind of investment. The farmer faces out-of-pocket costs for labor,
fertilizers, pesticides, energy and taxes; he faces fixed costs re-
IV-32
-------
lating to structures and equipment as well as to land. A pro-
longed period of negative net return will put the farmer out of
business.
The value of the land is an important determinant of the feasi-
bility of agricultural activity. In the first place, the purchase
of land for agricultural use will take place only if the purchaser
finds the price low enough to permit him to make a profit; land
will be retained in farm ownership as long as its price does not
exceed a level at which the return on investment in land falls be-
low what capital invested elsewhere could earn. In the second place,
land value (a fixed cost) affects property tax payments (an annual
out-of-pocket cost). Rising costs of land therefore increase the
costs of operating a farm as well as the costs of owning it. This
can be a serious problem at the fringes of urbanized areas, where
the value that accrues to land which satisfied the locational re-
quirements of intensive urban uses is usually considerably higher
than the income the land can generate in agricultural production.
Land which would bring $500 per acre for farming use may command
$2,000 per acre for urban uses.
While the farmer cannot influence the chages in the price of his
land which arise from its value to others for nonagricultural uses,
there are steps he can take to try to keep its agricultural value
at or near its nonagricultural value. He can grow higher value crops
and/or farm more intensively; in either case, the strategy would be
to increase his net return, thereby maintaining a constant capital/
output ratio. He can also simply hang on, hoping that rising agri-
cultural product prices will compensate for rising land values. If
these approaches are impractical, he (or eventually his heirs) will
sell his land, either in small parcels over a period of time or as
a block. [Particularly if the farm is advancing in years, the op-
portunity to sell off small parcels for urban development may pro-
vide income for retirement; this is one of the reasons why farmers
may object to restrictions on farm land conversions, as is reported
to be the case in eastern Adams and Arapahoe counties (Paul, per-
sonal communication).]
The following discussion of agricultural land use, conversion
trends and the effects of the current drought on both is not a pre-
diction of what will be happening in the near future in the Denver
region. Rather, it is a discussion which reflects on some of the
plausible consequences to agricultural and urban land use patterns
should the drought continue beyond this precipitation year. It is
by no means comprehensive of all the possible socio-economic effects
of which the drought might be a factor.
IV-3 3
-------
The current drought could accelerate existing trends to discon-
tinue agricultural activities as greater areas of farmland become
marginal due to a lack of adequate precipitation. Drought conditions
intensify competition for available supplies of water. The farmer,
faced with reduced precipitation, compensates by increased irriga-
tion or by growing crops requiring less water. The latter course is
limited because high value crops generally require greater amounts
of water. Also, the prices farmers have been getting the last few
years have often not covered production costs. Thus lower value
crops are even less attractive. Drought conditions also affect muni-
cipal and industrial water supplies. With these competing demands,
the farmer most often loses even if he or the canal company hold
senior water rights. This is because municipalities can institute
condemnation proceedings to convert agricultural water rights to
municipal uses. The cities of Westminster and Thornton are now in-
volved in such proceedings. Municipal water demand is somewhat more
flexible than agricultural demand. The farmer has less flexibility
in the amount of water he requires given climate and the crops he
must grow to receive an adequate return. Municipal and to a lesser
extent industrial water users can reduce their use significantly
without significant changes in lifestyle or operations. Little ad-
vantage has been taken in the Denver region of these differences in
water demand flexibility. Consequently, urban growth and drought
conditions, coupled with low or nonexistent returns from farming have
placed the agricultural sector under severe pressure. Because few
farmers can afford to retain their lands in fallow for very long,
many of them could be forced by financial considerations to sell out.
In a situation such as this, in which neighboring farmers are
not likely to be in a position to acquire more land, a "buyers market"
can develop for corporate agriculture interests and land speculators.
Whenever there is potential for a change in the type of land tenancy,
such as in this case, in which lands could change from family farms
to corporate farms and speculative land developments, there is also
potential for a change in the agricultural economy of the region.
The agricultural capacilities of lands purchased by agricultural
corporations would not likely be changed, However, the family farm
sector of the region's agricultural economy would be further reduced
by some degree. This is a great concern to many of Colorado's family
farmers (Reference 977).
In contrast, the agricultural capacilities of farmlands pur-
chased by land speculators are quite likely to be affected. Land
speculators operate under financial pressures resulting from sub-
stantial interest payments on mortgage notes and from a lack of pro-
duction income and investment dividends. A common strategy used to
realize a return on a rural land speculation is to minimize the time
IV-34
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the land is held by the speculator. Under this strategy the specu-
lator subdivides the property into the maximum number of parcels
local land use regulations and his financial resources will allow.
He then makes whatever minimum improvements are required and sells
the parcels as small farms and "ranchettes." The effect of these
smaller parcels is to diminish or eliminate the capability to con-
tinue the large scale agricultural operations that were possible
prior to subdivision. Although many smaller scale agricultural
activities are not precluded and some are actually made feasible
by the smaller parcel sizes, it is impossible to predict the utili-
zation plans of a diverse group of new land owners. While some new
owners may invest capital and labor into intense agricultural activi-
ties such as truck farming, others may desire only to raise a portion
of their own food and keep a few animals. It is all too common, how-
ever, for a new owner to himself be a speculator who will not use the
land productively but will attempt to divide it further.
This type of speculative activity generally occurs just outside
the urbanizing fringe, where local jurisdictions are unwilling to
grant entitlements for dense, urban development. Despite these ef-
forts to control "leap-frog" development, the newly diminished, large-
scale agricultural capabilities and fragmented ownership patterns of
relatively small parcels near the existing urban fringe establish
many of the requisite conditions for leap-frogging. Once dense de-
velopment is introduced into such an area, thereby establishing a
precedent for further development, the urbanizing fringe is extended
further into the region's agricultural hinterlands. This process oc-
curs with or without drought conditions, of course. As stated at the
beginning of this discussion, the factor contributed by the drought
is a stimulation of the rate at which the process operates, so that
farmlands are converted before the urban region has a well-defined
need for them.
To summarize, there is land value maximum beyond which it be-
comes uneconomic to farm. After this point is reached, the land
may still remain in production for a time as ownership changes from
the farmer to a nonagricultural corporation or landowner who leases
it back to the farmer. However, the point at which continuation of
agricultural use can be assured has by then been passed, and it be-
comes increasingly certain thatthe land will be urbanized. Farm
ownership patterns are a good index of how far the process has gone.
In California coastal counties still responsible for much of that
state's agricultural production, the number of farm-owner-operators
has fallen sharply since the 1950's; in San Mateo County; south of
San Francisco - a major center for production of brussel sprouts
and other vegetable crops - over three-fourths of the agricultural
land remaining in 1970 was already operated under leasehold arrange-
ment (Reference 989). Conversion to urban uses under such circum-
stances becomes a matter only of time.
IV-35
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Agricultural Land Conversion as an Environmental Issue
The competition between agricultural and urban uses is often
intense because both uses can frequently be provided most effi-
ciently on the same type of land. Urban uses and most crops can be
produced most economically on land with slight to moderate slopes,
good drainage, relatively little waste area and good water avail-
ability. Concern about loss of agricultural land may arise from a
socio-economic perspective or from an ecological perspective, or
from both.
Socio-economic impacts of'agricultural land conversion—
As the present century has progressed, the United States has be-
come increasingly important in the international economy as a food
(especially grain) exporter. Maintenance of food production both for
domestic use and for export is a major concern of some observers,
who fear that continued conversion of agricultural lands may ulti-
mately cause a domestic food shortage, resulting in an international
shortage: "There has been an overwhelming excess of potentially
arable land for all of history, and now, within 30 years (or about
one population-doubling time), there may be a sudden and serious
shortage" (Reference 998).
While this concern may have a theoretical validity, there seems
to be no real danger that the overall national supply situation will
be adversely affected in the foreseeable future by agricultural land
conversion. In the period since Worl War II, both Canada and the
Untied States have witnessed a considerable increase in urbanized
lands, but at the same time North American grain exports increased
dramatically, from 23 million tons in 1950 to 56 million in 1970
(Reference 983). This has been possible because of significant pro-
ductivity increases in both farm land and farm labor. Between 1931
and 1965, per acre wheat yield more than doubled, from 13 to 27
bushels per acre; corn production per acre more than tripled, from
23 to 73 bushels per acre (Reference 990). At the same time, the farm
population fell from 30 percent to less than 5 percent of the total
population (Reference 998). Given the overall decline in cropland
forecast to take place by the end of the century, the U.S. Department
of Agriculture nevertheless finds that the nation's cropland re-
sources can more than supply domestic and export needs (Reference
720).
However, while the future supply may be adequate, the cost may
rise. Over most of the past 45 years, the percentage of disposable
income Americans spend on food has declined. This trend has recent-
ly been reversed: in 1972, 150 of each take-home dollar was spent
on food, but in 1974 that figure had rise to 17<:. This change is
cause for concern because lower income families may have food costs
IV-36
-------
per-dollar-earned that are double or triple the national average.
Rising food costs are, in part, a land use problem; "Part of the
rise in food costs can be traced to higher input costs, expeci-
ally land and structural imbalances in farm units found in mixed
land use areas" (Reference 992). In the Denver region and in
Colorado generally the cost and availability of water are added
problems affecting the economic viability of agriculture.
Farmers need farmers for neighbors. Farm practices and operations
tend to conflict with urban uses. Expansion of farm size becomes
difficult where farming is at the urban fringe, and farm expansion
may be necessary to permit the application of new technology to in-
crease productivity. Average farm size nationally increased almost
30 percent between 1959 and 1969 (Reference 996). The evolution of
a land use pattern that intersperses actual and potential urban uses
with agricultural uses is inefficient and costly both to food pro-
ducer and consumer. The situation of agriculture as a local land
use is therefore a legitmate environmental concern.
Impacts of agricultural land conversion on the natural environment—
Preservation of land in agricultural use results in a number of
benefits. Generally, the effect on air is positive since any green
cover contributes to oxygen supplies. However, if drought and/or eco-
nomic conditions result in significant areas laying fallow, wind ero-
sion and particulate air quality problems will result. Agriculture
may use significant supplies of fresh water, but some ground water re-
charge takes place. While farm runoff can be a problem, farmers try
to minimize soil erosion. Farming also presents a generally attractive
landscape, represent-ing a minimal departure from the "natural state"
of the environment. Finally, urban land uses which replace farming
would typically have more adverse impacts on the natural environment
associated with them.
Agricultural land conversion is part of an overall assessment of
land use change which is to be addressed in environmental impact
statements. Farmlands classified as "prime" or "unique" are subject
to specific consideration udner current federal and regional policies.
The U.S. Council on Environmental Quality has stated that "efforts
should be made to assure that such farmlands are not irreversibly con-
verted to other uses unless other national interests override the
importance of preservation or otherwise outweight the environmental
benefits derived from their protection" (Reference 103). The bene-
fits cited include provision of open space, scenery and wildlife
habitat; it is also pointed out that prime lands by their nature pro-
duce more food with less erosion and lower fertilizer and energy re-
quirements. Policy of the Denver Regional Council of Governments
calls for discouraging new development in these areas. (Reference
204).
IV-37
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Conversion of Agricultural Land in the Denver Region
In the period between 1960 and 1970, land devoted to urban uses
in the Denver region increased by 12.3 percent while land devoted
to agriculture declined by 6.8 percent. In all, about 33,600 acres
were lost to agricultural production, while 41,700 were added to
urbanized areas. Most new urban land come out of the agricultural
category, though some came out of vacant and public use categories.
The decline in agricultrual use affected every county, as Table IV-
J.shows. How much of this loss was prime agricultural land is not
known.
TABLE IV-J. AGRICULTURAL LAND USE IN THE FIVE-COUNTY
REGION: 1960, 1970 (1,000 acres)
•3
County
Adams
Arapahoe
Boulder
Denver
Jefferson
Totalb
Year
1960
1970
1960
1970
1960
1970
1960
1970
1960
1970
1960
1970
Total
Acres
243 . 0
126.8
282 . 9
63.4
498.2
1214. 3
Developed
36.9
46.0
33.2
36.7
64.5
72.6
46.9
52.6
158.6
174.0
340.1
381.7
Undeveloped
Agricultural
189.5
177.2
80.2
74.9
139.0
133.9
7.4
2.0
76.9
71.3
492.9
459.4
Vacant
16.6
19.8
13.4
15.2
79.4
76.4
9.1
8.8
262.7
252.9
381.3
373.2
a
Excludes eastern Adams and Arapahoe Counties and western Boulder County.
Detail may not added to total due to rounding.
Source: Gruen Gruen + Associates based on Reference 205.
The forces affecting agricultural activity which were described
in the preceding pages will continue to influence land development pat-
terns in the Denver region through the end of the century. No fore-
cast of agricultural land conversion was found in the course of our re-
search; however, it is possible to project conversion of agricultural
land to urban land based on existing trends a|s a way of estimating the
magnitude of change which can reasonably be expected if a year 2000
population of 2.35 million is attained.
IV-3 8
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Three approaches were used in making this projection. The
first was to extrapolate existing trends. The second was to cal-
culate the loss in agricultural acreage associated with each added
unit of population in the 1960-1970 period and to assume the same
association will pertain through the year 2000. The third was to
measure the acreage of prime soils lost from maps of future land
use. Only the Denver urban region was considered; eastern Adams
and Arapahoe and western Boulder Counties were excluded, as these
areas are not expected to experience urbanization.
As Table IV-K indicates, agricultural acreage in the year 2000
would be between 325,000 and 359,000 acres, depending on the trend
line being considered. In the former case, a reduction of 29 per-
cent (134,100 acres) in agricultural land is projected; in the latter
case, a reduction of 22 percent (100,800 acres) is projected. Note
that the coefficient of conversion (acres converted per person added
to the population) rises the more urbanized the area. This is because
in densely settled areas (such as Denver County) land development
tends to have a larger complement of nonresidential uses, while in
sparsely settled areas (such as Jefferson County) new development is
primarily residential.
The projections of agricultural land presented in Table IV-K
are trend projections based on the conversion experience of the de-
cade between 1960 and 1970. As is the case with any projection
based on past trends, there is an implicit assumption that the con-
ditions which applied in the historic period (1960-1970 in this case)
would also apply in the future. This assumption may not be valid.
The supply of agricultural land in 1970 differs in location and type
from the 1960 supply, and the spatial distribution of urban growth
between 1970 and 2000 is not expected to resemble the 1960-1970
pattern. Thus, the projected totals may be reasonable, but the dis-
tribution by county may be somewhat different. DRCOG, as shown in
Table IV-F indicates that the total land in agricultural, undevelop-
able, and other vacant categories would be about 336,000 acres. As
this grouping includes additional land use categories, the total may
be considered an upper limit. Thus the 325,000 acre projection in
Table IV-K appears more reasonable. The conversion of 134,000 acres
represents a 29 percent reduction in agricultural land.
A comparison of future land use patterns with the distribution
of prime agricultural soils reveals the extent of possible loss of
existing and potentially productive prime agricultural land to urban
expansion. This comparison assumes that the prime agricultural soils,
as shown on Map D, are a limited irreplaceable resource and the future
land use patterns as defined by DRCOG, see Map I, will in fact mater-
ialize. The results of the comparison are shown in Table IV-L. It
IV-3 9
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TABLE IV-K. PROJECTED YEAR-2000 AGRICULTURAL LAND
IN THE FIVE-COUNTY REGION3 (1,000 acres)
Adams
Arapahoe Boulder
Denver
Jefferson
Total
Year 1970
177.2
74.9
133.9
2.0
71.3
459.4
Year 2000 based on
extrapolation of
1960 to 1970 trend
135.0
57.0
114.1
none
53.6
358.6
i
j>
o
Year 2000 based on
per capita agri-
cultural land
conversion from
1960 to 1970d
129.5
46.0
106.8
none
43.0
325.3
Coefficient of
conversion
0.1885
0.0906
0,0947
0.5208
0.0552
0.1168
Excludes eastern Adams and Arapahoe and western Boulder Counties.
DFrom Table II-F.
"County projections have been proportionally adjusted to sum to totals.
One study (Ref. 719) reporting on Adams and Arapahoe Counties found a coefficient
of conversion for cropland of 0.148 for the two-county area. Figures in this
table cover land in all agricultural uses, not just cropland.
Source: Gruen Gruen + Associates based on Table IV-F and Refs. 205 and 262.
-------
is estimated that no more than 5,000 acres of prime agricultural
soils would be lost in Jefferson County for a total loss in the
region of about 38,000 acres. This represents about 23 percent
of the prime agricultural soils in the region.
TABLE IV-L. ANTICIPATED CONVERSION OF PRIME AGRICULTURAL
LAND AS A CONSEQUENCE OF URBAN EXPANSION TO
TO YEAR 2000
Number of acres expected
County to be urbanized
Adams 20,000
Arapahoe 8,000
Boulder 5,000
Denver Insufficient data
Douglas 400
Jefferson No published data
Weld No published data
These sharp declines in agricultural land use in the five-
county area represent only part of the likely future state of agri-
cultural activity in the region. As the agricultural lands on the
fringe of the Denver urbanized area are gradually converted to urban
use, there will be increased pressure to expand and intensify agri-
cultural activity in areas just beyond the metropolitan region. These
pressures would be felt most strongly in eastern Adams and Arapahoe
counties, southern Weld County and northern Douglas County. If sup-
plies of water for agricultural use permitted, increased agricultural
production in those areas would take place, with little loss in over-
all production despite urbanization of some cropland. However, water
is a far more important constraint on agricultural activity than is
land in this region, and local agricultural experts report that ur-
banization threatens continued agricultural activity, less because
it absorbs agricultural land than because domestic water users have
priority over agricultural users in the allocation of water. The
condemnation of water rights may make farming economically infeasible
long before pressures for conversion of agricultural land are ex-
perienced.
IV-41
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AIR QUALITY IMPACTS
Introduction
For several years, it has been presumed that acceptable air
quality in Denver was one of the main limiting factors for future
growth in Denver. The "carrying capacity" of the Denver airshed
appears already to be exceeded, given current frequent violations
of air quality standards. It was then anticipated that planned
growth, which required the support of wastewater treatment
facilities, would add to the problem and lead to unacceptable air
quality in Denver from the present to the year 2000. This was
expected to be true in spite of adoption of a Denver Transporta-
tion Control Plan which specified measures which might be taken
to improve air quality. For this reason, the analysis of air
quality was performed for this EIS to investigate the probable
future impacts and potential mitigating measures. This analysis
was performed by Systems Applications Incorporated under contract
to EPA. A report of this work is available upon request and is
listed in the Bibliography as reference 998.
A major goal of the Denver study was to predict the effect
of land use and population forecasts used in planning the eight
proposed wastewater treatment facility plans (201) and the Clean
Water Plan (208) on future Denver (1985 and 2000) air quality.
In order to assess the relative impacts of such actions, air
quality was modeled for future years for various pollutants to
attempt to estimate the air quality consequences of future growth.
Since urban growth and development and the attendant increase
of pollutant emissions depend on factors in addition to the
availability of sewage systems, and In particular, since urban
development depends on decisions not yet made, predictions of
future growth are not simulations of complete certainty. The
analysis of Denver's future air quality has become an exercise in
hypothesis. The question is not so much "What will Denver's air
quality be? but rather, "What will Denver's air quality be if...?".
There is no single unique analysis of future air quality. The
variation of air quality with changes in assumptions is an
important aspect of the analysis, but to define these changes,
there must be an initial condition from which to measure
departure.
The initial or base condition of Denver's air quality for
future years under study, 1985 and 2000, is taken to be the state
which would most probably be realized. In this case, it means
the air quality impacts from emissions which do not strictly
meet federally mandated levels for automobiles and future growth.
IV-4 2
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Since plans and projections for Denver's future have been formulat-
ed, examined and accepted in the absence of this air quality
analysis, those plans become the "base" for assessing probable
future air quality impacts. Variations from this base case for
future years are evaluated in the section on mitigating measures.
Modeling Air Quality in Denver
The Denver Air Quality Model (DAQM, reference 998) was
utilized to predict ozone concentration. Modeling of photo-
chemical oxidants is exceedingly complex. The major oxidant of
concern, ozone, is not generally emitted from man-controlled
sources. Significant background concentrations of ozone from
natural sources can and do occur. It is generally believed,
however, that critical ozone concentrations in urban airsheds
are produced by chemical reactions in the atmosphere between
atmospheric oxygen, nitrogen oxides, gaseous hydrocarbons, and
other less significant compounds. The primary sources of
nitrogen oxides and hydrocarbons in the urban atmosphere are
combustion machines, most importantly, motor vehicle engines.
The primary nitrogen oxide species emitted is nitric oxide
(NO). In the presence of large amounts of NO (relative to N0£
quantities), it typically takes from one to several hours for the
N02/NO ratio to become high enough for significant ozone to
form. In such a time period, precursor materials are likely to
blow far from their sources and become significantly dispersed.
For this reason, ozone concentrations are likely to be quite
sensitive to wind patterns and atmospheric mixing. Nonreactive
pollutant concentrations are often more clearly related to wind
speed, direction and stability near their source, than to
regional wind patterns, since they become quite diluted for long
dispersion times. (Note: This is true of ozone precursors
also, but since little ozone is formed very near the sources,
high ozone concentrations are not expected there.)
Models which do not take account of wind patterns are not
expected to predict ozone patterns well; therefore, in this
study, a grid based physio-chemical model was used for the analy-
sis of regional photochemical oxidant.
Particulates and N02 were analyzed with the Gaussian Climato-
logical Dispersion Model (CDM); however, it is very important
to note that most N02 in an urban atmosphere is not emitted, but
is a product of photochemical reactions j_ust as is ozone. Thus,
CDM, which does not include chemistry algorithms, assumes all
emitted NO to be equivalent to N02- This is probably valid for
far downwind locations, but is clearly not even approximately
true at the times and places for which maximum N02 concentrations
IV-43
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are computed with COM. Therefore, the reactive, model DAQM was
also run to predict hourly NC>2 concentrations for the years 1974,
1985 and 2000. Annual average N0£ concentrations were then
inferred from the DAQM results. See Reference 998.
Carbon Monoxide (CO) is inert and does not react in the
atmosphere. As a result, carbon monoxide concentrations are
generally highest near the source (e.g., from automobiles, the
highest concentrations occur along the roadway and intersections).
A grid model does not estimate "local hot spot" areas but rather
calculates averages within the area of the grid. However, for a
regional scale analysis, a grid model is useful for obtaining
trends and regional large scale CO concentrations. For the
regional scale analysis, the DAQM grid model was utilized to
evaluate future CO levels.
Information on further localized "hot spot" CO concentrations
was taken from the 1-470 air quality impact study performed by
the Colorado Division of Highways (CDH). In these calculations,
CDH used the California Line Source Model to evaluate the micro-
scale CO effects.
Data and Assumptions
For the purposes of evaluating and modeling present and
future air quality in the Denver Metropolitan Area, a number of
emission files of estimated present and future emissions of
various air pollutants were provided by the Air Pollution Con-
trol Division of the Colorado Department of Health and by the
California Division of Highways.
In general, highway and nonhighway traffic account for a
major fraction of most of the pollutants emitted. While auto-
mobiles and other vehicles do not directly contribute to the
particulate problem, a large percentage of the particulate
matter results from materials on streets thrown up by vehicles
(45 to 60 percent of the total particulate emissions). Point
sources contribute the next largest percentage of emissions
and these sources account for as much as 50 percent of the
total NOX emissions as well.
The emissions which were utilized in the DAQM validation for
the days in 1975 and 1976, consisted of reactive hydrocarbon
and nitrogen oxide emissions to determine photochemical oxidant
concentrations. To determine CO concentrations, estimates of
these emissions were also input into the DAQM model.
Future emissions were estimated with emission factors based
on recent auto emission test results. These emission estimates
IV-4 4
-------
are higher than the current and optimistic EPA vehicle emission
factors from AP-42 Supplement #5 for 1985 and 2000. This approach
was used because recent auto emission tests demonstrate an
inability to achieve the required emission reductions in new cars
and the inadequacy of emission control system maintenance.
Point sources were projected to the years 1985 to 2000 by
assuming that increases in emissions were directly proportional
to increases in area of industrially-zoned land. Future zoning
changes were determined from various land use plans and popula-
tion projection forecasts. Space heating and other area-wide
emissions were computed based on population forecasts and pro-
jected land use allocations.
The emissions that were used in predicting 1985 air quality
are presented in Table IV-M. Emissions were estimated in the
summer and winter months and revealed the following:
1. Winter emissions exceeded summer emission for all
three pollutants (reactive hydrocarbons, nitric
oxides, and carbon monoxides). This was due to an
increase in auto emissions in the winter. The most
significant differences were obtained from carbon
monoxide emissions.
2. Automotive emissions of carbon monoxide, hydro-
carbons and NOX are higher than Supplement 5
estimates because of the lack of proper main-
tenance of emission control systems, the failure
of emission controls equipment, and the apparent
inability to achieve the required reduction of
certain pollutants for new cars.
3. Point sources contribute almost 20 percent of the
reactive hydrocarbon emissions and about 10
percent of the carbon monoxide emissions.
Table IV-M. Denver Emissions Inventory (tons per
day) for 1985 Air Quality Projections
Season
Winter
Summer
TOTAL
Reactive
HC
220.5
154.2
374.7
NOX
346.0
310.8
656.8
CO
3,715
1,776
5,491
Particulates
130
130
260
Source: Systems Applications, Inc.
IV-4 5
-------
Emissions utilized to project year 2000 air quality levels
are presented in Table IV-N. Emissions for this year were cal-
culated on a summer and winter basis for different source cate-
gories. An examination of this table reveals the following:
1. Winter emissions exceed summer emissions for all
three pollutants (hydrocarbons, nitrogen oxides,
and carbon monoxide).
2. Emission of carbon monoxide and nitrogen oxides
decrease from 1985 but hdrocarbons are predicted
to increase over 1985 levels. The hydrocarbon
increase is due primarily to increases in traffic,
difficulty in achieving the required emission
levels, a failure of emission control devices
and/or lack of proper maintenance programs.
Table IV-N. Denver Emissions Inventory (tons per
day) for 2000 Air Quality Projections
Season
Winter
Summer
TOTAL
Reactive
HC
180.6
124.4
304.0
NOx
327.2
276.9
604.1
CO
2,370
1,266
3,636
Particulates
158
158
316
Source: Systems Applications, Inc.
Model Validation—
Ozone Validation
The Denver Air Quality Model (DAQM) was validated for ozone
on summer days, 29 July 1975, 28 July 1976, and 3 August 1976;
since these were the only days for which meteorological data
were available, and for which sufficient air quality data were
available with which to compare the simulation results. The 1975
day did not approximate a worst day for 1975, but significant
violation (11 pphm) of the ozone standard (8 pphm) was observed.
The second (18 pphm) and third (16 pphm) highest ozone observa-
tions of 1976 were on the two days of that year simulated. The
two 1976 summer days were subsequently used with future emissions
to predict 1985 and 2000 air quality.
The simulation for 28 July 1976 yielded a peak computed
ozone level at any monitoring station of 16 pphm, the same value
as was actually measured. However, the peak ozone level computed
IV-4 6
-------
for that day occurred elsewhere in the region, and was 22 pphm.
The simulation for 3 August 1976, computed a station peak level
of 15 pphm. The observed value was 17 pphm. Again, the peak
computed anywhere in the region was higher than any observed
value, namely 24 pphm. Therefore, there is no assurance that
current monitoring stations are recording the peak ozone levels
occurring in the region, or that they will do so in the future.
Nearly 300 comparisons were made between hourly-average con-
centrations computed for grid cells, and concentrations observed
in the atmosphere at corresponding points. These comparisons
are presented and discussed in Reference 998. Although there
were substantial differences between computed and observed con-
centrations on some occasions, on the whole, impressive corre-
spondence between them was noted. The differences were not so
large as to distinguish between simulation and observational
error. Therefore, the simulation errors are only bounded by the
noted differences. It is likely that much of the difference is
due to observational error.
The plots in Figure IV-C show differences between computa-
tions and observations averaged over time at stations, over
stations at each hour over both time and place for each simula-
tion day and for all days. The averages were examined for
evidence of regularities that would suggest correctable error in
the formulation of the model. Computed results did average
lower than observations early in the morning and late in the
afternoon. Generally, the model predictions compared very well
with observations.
Carbon Monoxide Validation—
The carbon monoxide validation actually did not produce as
favorable results as did the DAQM ozone model. At certain
monitoring locations for some of the simulated days, good agree-
ment between simulated and observed concentrations was found.
In other cases, substantial differences exist between observa-
tions and simulated concentrations. In part, this is due to the
nature of the computer model used. The model simulates average
CO concentrations over a four square mile grid cell, whereas air
quality monitoring stations sample air at a single point.
Therefore, the model predicts regional scale CO concentrations
while monitoring stations are greatly influenced by very local
CO emissions from nearby road and traffic intersections.
NOX Validation—
Available N02 information was totally inadequate for valida-
tion of the models for these species. Since the Climatological
Dispersion Model (CDM) was not used in this study for drawing
IV-4 7
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I
-O
IX
a OBSERVATION AVERAGES
o PREDICTION AVERAGES
-D a *
—~
TIME OF DAY, hourly averaging periods
start hour
stop hour
THE VARIATION OF AVERAGES OVER ALL
STATIONS OF OBSERVATIONS AND PREDICTIONS
-------
inferences relative to future NOX levels, no attempt was made to
validate CDM for purposes of NC>2 prediction. The inferences
drawn for NO/NC>2 probable impacts and mitigations have not been
scientifically validated and merely represent best estimate.
Farticulate Validation—
The CDM was used to predict particulate concentrations and
was previously calibrated by the Colorado Department of Highways.
Background levels and the calibration coefficients previously
determined were utilized for the CDM runs in the Denver study
and no attempt was made to validate the background or calibration
coefficients.
Denver Air Quality Projections
Estimates of present and future air quality in the Denver
region were made from model computations using the Denver Air
Quality Model (DAQM) and the Climatological Dispersion Model (CDM).
Computations were made for comparison with each National Ambient
Air Quality Standard (NAAQS). The DAQM, a "real time" model was
used to estimate the highest occurring hourly average concentra-
tions of ozone, carbon monoxide, and nitrogen dioxide. The DAQM
results were used to make inferences regarding potential violations
of the annual average N02 standard. A much more complete descrip-
tion of the air quality modeling efforts discussed here can be
found in reference 998.
Ozone—
As described previously, two of the three summer days for
which data were available were reasonably representative of
worst case ozone episodes. Results of future simulations using
meteorological data from these days and compared with 1976
simulation results show that peak ozone concentrations are
predicted to drop from 24 parts per hundred million (pphm) in
1976 to 15 pphm in 1985 and 11 pphm in 2000. For each of these
years, the predicted ozone concentrations exceed the standard
of 8 pphm.
E.esults of the model simulations also showed decreases in
the area extent of violation over time. In 1976, the area
computed as exceeding the ozone standard covered a maximum of
300 to 400 square miles at any one hour. By 1985, the computa-
tions show only about 132-184 square miles in violation of
the standard. By 2000 the area is reduced to 24 to 40 square
miles.
IV-49
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Carbon Monoxide—
Carbon monoxide concentrations were computed with DAQM for
a bad (poor dispersion) winter day in November 1974. Winter days
in the Denver Metropolitan Area tend to be most crucial for non-
reactive pollutants, since the low solar intensity and low wind
speeds permit the shallow morning mixing layer to last longer
and sunlight is not required for production of the nonreactive
pollutants.
The concentration gradients of nonreactive pollutants can be
much larger than for ozone. This is because peaks occur very
close to the sources (primarily traffic for CO) before disper-
sion dilutes the pollutant material. As a result, the definition
of peak concentrations of CO is very difficult. CO monitors on
opposite sides of a heavily travelled street can easily show con-
centrations differing by a"factor of two or even an order of
magnitude. The DAQM computation has a 2-mile resolution and,
therefore, the microscale street effects would be suppressed.
Under present conditions, CO violations can surely be found
in any major urban area at particularly critical spots such as
industrial, shopping centers or stadium parking lots or at
busy intersections. This is known to be true for Denver. The
DAQM predicted on a regional scale, that the average CO concen-
tration over an 8-hour period was 16 parts per million (ppm) for
1985, and 5 ppm for 2000. The 8-hour standard is 9 ppm.
Therefore, on a regional scale, CO concentrations will exceed
the standard for 1985, but be below the standard by 2000.
A 1985 and 2000 microscale analysis utilizing the California
Line Source Model was conducted by the Colorado Division of
Highways to evaluate the microscale effects for its proposed
1-470 alternatives. Analyses of the modeling results indicates
that the highest level of CO for the years 1985 and 2000 will
be experienced along the Santa Fe Drive.
The data computed for sensitive receptor areas indicates
that concentrations will exceed the standard for the worst
meteorological case. Furthermore, the standard was predicted
to be exceeded in the Cinderella City area in 1985 and is ex-
ceeded for most traffic concentrations in year 2000. Since
the result of these analyses were based on current, yet
optimistic emission factors, it is probable that these results
are low. Also, calculations in this analysis were made on a
one-hour basis and it would be expected that many 8-hour "hot
spots" violations would occur in 1985 and 2000, since the 8-hour
air quality standard is more often exceeded than the one-hour
standard.
IV-50
-------
Nitrogen Dioxide—
Estimates of long-terra nitrogen dioxide (N02) concentrations
are difficult to determine. The primary emitted species is NO.
After entering the atmosphere, NO is typically oxidized to N02 in
the same complex photochemical reaction that generates ozone.
Because NO eventually becomes N02, the typical standard violation
analysis computes, not N02, but NOX concentrations assuming all
NOX emissions are N02- Since an annual average is desired (the
standard for N02 is annual average), NOx modeling is usually
done with EPA Climatological Dispersion Model (COM) or other
annual Climatological models.
While all NO may eventually oxidize to N02, all emitted NO
is clearly not N02 at all positions along its downwind path. NOx
is particularly not N02 while it is still near its source where
it is densest. CDM can therefore be expected to seriously over-
estimate N02 in the denest source areas of a region. CDM
estimates should be more accurate near the periphery of the
modeling region.
CDM is a calibrated model; that is, its results are multiplied
by a factor to make them correlate with observed conditions.
The Denver region has had just one N02 monitoring station which
is the center of the downtown NOX source area. CDM results were
calibrated with data from this station and they should be equiva-
lent to the observation at that site for the calibration year.
The results from CDM should be progressively more in error (under-
predicting) with distance from the calibration site. Since the
emissions of all interacting species change differently years
into the future, the calibration should not be valid for
future years.
The problem of the complex photochemical reactions for N02
formation could be resolved by using DAQM; in fact, NO and N02
concentrations are computed by DAQM. Use of this model does
not, however, give annual averages and therefore direct compari-
sons with the N02 standard cannot be made. Peak N02 hourly
average concentrations computed with DAQM for worst case summer
days show decreases in N02 from 1976 to 1985 and again to 2000.
This is in contrast to predictions of steady increases of
N02 using the erroneous assumptions of CDM. The conclusions
that may be drawn are:
1. Observations show current compliance with the NAAQS
standard of 5 pphm N02 on an annual basis, however,
the one station recording N02 concentrations may
not be located in an area of high concentration.
IV-51
-------
2. Annual average N02 concentrations may not increase
in future years. They may decrease somewhat.
Particulates—
Annual average particulate concentrations were computed with
CDM. The model results were calibrated with observational data.
The predicted concentrations are so high (four to five times the
State standard) that current and future violations are expected.
The NAAQS for particulates was predicted to be exceeded over 460
square miles in 1974, 548 square miles in 1980, 688 square miles
in 1985, 716 square miles in 1990, and 724 square miles in 2000.
Figure IV-D shows the average annual particulate concentration
projections for various areas around the Denver Metropolitan Area.
A summary of the results of the analysis of future Denver
region air quality is presented in Table IV-0.
Uncertainty of Results
Air quality impacts previously discussed assume that emissions
for future automobile model years will be higher than required
by the Federal Emissions Control Program. This assumption is
based on the present experience indicating that a fraction of
vehicles experience early catalyst failure, another fraction have
engine maladjustments, and the remaining fraction are properly
tuned vehicles with operating catalyst. It is also assumed that
as a model year becomes older, more vehicles experience catalyst
failure and become maladjusted. If these fractions are all taken
into account, it results in limited success of the emissions
control program. Any significant variance from these assumptions
could result in different results as explained in the discussion of
effectiveness a vehicle inspection and maintenance program in the
section on Mitigation Measures for Air Quality.
The vehicle emissions used in this analysis also assume some
delay in the required implementation date for emission control
limitation. It is assumed that the implementation dates for
carbon monoxide and hydrocarbon standards of 3.4 grams per mile
and 0.41 grams per mile, respectively, will be delayed one year
from 1978 to the year 1979. Required implementation date for
the NOX standard was assumed to be delayed until 1981. The
presently required date is 1978. Due to the apparent inability
of the auto manufacturers to constantly meet the present
standard requirement, these assumed set backs may be conservative.
The modeling of ozone and carbon monoxide utilized meteoro-
logical data from two summer days in 1976 and one winter day of
1974, respectively. Therefore, as a result, assumed future
IV-5 2
-------
FIGURE IV-D
180
160
140
120
100
80
60
40
o DENVER
A LAKEWOOD
• NORTHGLEN/THORNTON
D BROOMFIELD/WESTMINSTER/ARVADA
XX ENTIRE REGION
• S. METRO
X AURORA
A JEFFCO URBAN
1975
1980
1985 1990
YEAR
1995
2000
IV_53 AVERAGE PROJECTED PARTICULATE
CONCENTRATIONS 1974 TO 2000
-------
Table IV-0. DENVER AIR QUALITY PROJECTIONS
f
<_n
.p-
Model
DAQM
DAQM
DAQM***
COM
Pollutant
Ozone
CO
CO
N02
Part.
Federal
standard
8 pphm 1-hr.
35 ppm 1-hr
9 ppm 8-hr.
82 yg/tn3
annual average
75 yg/tn3
annual average
Computed maxima
D 1 3. t G
standard 1976
24
26
15
79
45 yg/m3 168
annual average
1985
15
27
16
75
217
2000
11
6
5
74
229
Area of exceedance
(mi2)
1976
300-400
A
*
*
460
1985 2000
132-184 24-48
* &
* *
688 724
*Not calculated
**0bserved Value
***Annual averages determined from peak hour values based on proportionality between
observed values. See Reference 998.
-------
meteorological conditions are identical to those that occurred
on these days. Although it is assumed these days are representa-
tive, and to some degree typical, of higher ozone and CO pollution
episodes, meteorological conditions will vary from year to year.
For this reason the sensitivity analysis was performed for ozone
to determine the variability of results obtained to changes in the
meteorological assumptions. Lower average windspeed and shallower
average mixing layers than were originally estimated from the data
were investigated. Specifically, a 1/3 decrease in windspeed and
in mixing layer of thickness was assumed separately and together.
The decreases were proportionate in every grid point, thus all
wind patterns were preserved. Results of these model simulations
showed that a 1/3 change in windspeed increased the peak ozone
concentration by only 1 pphm but increased the total area subject
to standard violations by 80 square miles. Nearly the opposite
was the case for the 1/3 lowering of the mixing layer thickness,
with peak ozone concentration increasing by 4 pphm, but the area
of violations increasing only by 30 square miles. Both meteoro-
logical parameters would change peak ozone concentrations by much
more than the sum of the individual effects. For 1/3 decrease
in both windspeed and mixing layer thickness, peak ozone con-
centration increased by 8 pphm and the area of standard increased
by approximately 100 square miles. It appears that the assumed
meteorological estimates would have to be in error by a substan-
tial amount in order to invalidate the previous ozone results.
For the meteorological conditions evaluated, it is assumed
that there is no carry over of pollutants from one day to the
next, nor any reentry of pollutants during a single day after
they have left the modeling area. In Denver, the afternoon
mixing layer is typically quite deep, as compared with morning
conditions. This, together with the lack of any topographic
barrier on the east and north, which are both downhill and down
wind in a nighttime drainage flow, make carry over of pollutants
from one day to another unlikely. This conclusion is reinforced
by the observation that the peak ozone days occurred singly in
the summer monitoring program of 1976.
However, it appears that wind reversals during midday hours
can bring the pollutant cloud back to the region after it has
left the model boundary. For ozone the situation cannot be
treated correctly by the model since the concentrations changed
by unknown amounts while material is outside the analysis
region. Given the rapid thickening of the mixing layer, dilution
is likely to be far advanced when reentry of the ozone cloud
becomes an issue.
While the possibility exists that days could occur when
the characterizations involved are not valid the situation
IV-55
-------
described is, however, consistent with maximum ozone concen-
trations observed in Denver.
Since the boundaries of the Denver Air Quality Model is
defined by a 30 x 30 mile square, centered over Denver, the
potential downwind affects are not modeled. As discussed in the
the section on Mitigation of Air Quality Impacts, downwind ozone
and N02 concentrations may also be a problem under certain
conditions.
The annual average particulate results are estimated with
the use of a "calibrated" mod-el which factor the model results
to more closely resemble the observations. Also, a large fraction
of the model results are attributed to "background" particulate
concentrations rather than identified emissions. Therefore,
particulate results are sensitive not only to the estimated
particulate emissions but, also, to the assumed "background"
level and calibration constants.
In predicting future N02 concentrations in the Denver region,
uncertainty exists as to the present level of N02 concentration
since there is only one N02 monitor and it may not be located so
as to pick up the peak concentrations. This is important in
that the probability of future violations' of the N02 standard is
based in part on present measured concentrations of N02. If, in
areas of the Denver Region, the N02 standard is being violated
where no monitoring presently exists, the likelihood of future
violations of the N02 standard would be increased.
Effects of Agricultural Crops
The effects of air pollutants have been well documented.
However, much is yet to be learned, and methods for forecasting
dollar loss as a function of air quality and crop type are not
well developed. Reference 908 is the only method which has been
applied to obtain national estimates. This method, termed the
Factor Method, provides a means for determining loss from a series
of factors which account for emissions, meteorology, frequency
of episode days, and crop sensitivity. Alfalfa is the only crop
for which an alternative method is available. See Reference 909.
This method relates dose, in pphm - hours exposure to ozone, to
percent reduction in productivity. Using 1974 ozone data from
the Welby air quality monitoring station, dollar losses for
alfalfa ranged from 16-24 percent. Using the Factor Method, a
loss of 20 percent for alfalfa is forecast. When the Factor
Method is applied to the crops produced in Adams, Arapahoe, and
Boulder counties, generally downwind of Denver, a total loss of
over 16 percent is forecast. This amounts to about $6,800,000.
IV-5 6
-------
Air quality is expected to improve insofar as ozone is
concerned. If the same crop mix and dollar value is assumed for
the next 25 years, and a 5 pphm threshold for crop damage is
assumed, the dollar losses for 1985 and 2000 are forecast to be
about $3,600,000 and $2,200,000, respectively. This amounts to
about $95,000,000 over the 25 year period. If the future ozone
levels were reduced by 20 percent, the loss over the 25 year
period would be reduced 21 percent to $75,000,000.
IV-57
-------
WATER QUALITY
Three major alternative wastevater collection and treatment
programs for the study area were dientified and discussed in Section
III of this document: the LOCAL, REGIONAL and NO-ACTION alterna-
tives. Eight 201 facilities plans and their respective planning
areas, as shown on Map J. encompass the individual units of these
three major alternatives and collectively serve the majority of the
study area's stream basin, as discussed in Section II. The status
of existing and proposed wastewater facilities is given in Table
IV-P. The proposed 201 facility plans addressed in this EIS are
underlined.
The following subsections will assess the likely water quality
impacts and improvement in beneficial stream uses both for the im-
plementation of these three major point-source control alternatives
and for feasible nonpoint-source controls.
Background
From a review of information presented in Section III of this
document, it can be noted that the local alternative is typified by
the expansion and upgrading of existing facilities, with satellite
plants in the Cherry Creek, Clear Creek and lower South Platte basins,
whereas under the regional alternative the satellite plants would not
be constructed, and excess wastewater flows above the capacity of the
upgraded existing facilities would be sent to the Denver NOrthside/
MDSDD #1 complex. The no-action alternative is typically the same as
the local one except for various time delays in the expansion and up-
grading program. Under all the alternatives, the levels of treatment
to be provided include additional removal of BOD5 and suspended solids
to effluent levels of 20 mg/1 each, and reduction in effluent ammonia
levels to approximately 3 mg/1. In addition, residual chlorine levels
in the effluents will be reduced. The location and sizing/staging of
the various wastewater collection and treatment facilities for the
local and regional alternatives are shown on Figures III-A and III-B,
respectively, and are discussed in greater detail in Section III.
The Federal Water Pollution Control Act Amendments of 1972 indi-
cate that it is the national goal to meet by 1983 levels of water
quality which provides for "protection and propagation of fish, shell-
fish and wildlife and provide for recreation in and on the water."
The Act also declares as a national goal "that the discharge of pol-
lutants into the navigable waters be eliminated by 1985."
During the course of the 208 planning program in the Denver area,
levels of water quality necessary to meet the 1983 goals have been
suggested by the Colorado Water Quality Control Commission; and the
Denver Regional Council of Governments (DRCOG), along with their con-
IV-53
-------
Table IV-P. STATUS OF EXISTING/PROPOSED WASTEWATER COLLECTION AND TREATMENT FACILITIES
UNDER THE LOCAL, REGIONAL AND NO-ACTION ALTERNATIVES
Basin
Existing or
proposed facility
Status under
local alternative
Status under
regional alternative
Status under
no-action alternative
Bear Creek
Cherry Creek
Morrison
Glendale
f
Sand Creek
Aurora
(New plant 30-40 ragd
at Aurora site, re-
named Sand Creek
Satellite)
Fitzsimtnons
Assumed will maintain present level
of secondary treatment but will add
nutrient removal to reduce effluent
ammonia (NH,—N) to 3 mg/1
Assumed will maintain present level
of secondary treatment but will add
.nutrient removal to reduce effluent
NH_-N to 3 ing/1 and reduce
residual Cl.
AWT plant to be built in 1985 only
if feasible at that time. Effluent
at secondary level when used for
reuse (industrial/agri), tertiary
when discharged to Cherry Creek.
Flows above plant capacity sent
to Denver/Northside/Metro //I
system
Expanded/upgraded new facility to
meet effluent levels of 20 mg/1
each for BOD and suspended solids
(SS) and NH -N to 3 mg/1. Residual
chlorine (CI) reduced to 0.005 ing/1
and fecal coliform (Fc) to 1000 MPN/
100 ml. Effluent to Quincy Reservoir
for reuse. Flows above plant capacity
to Metro #1 via interceptor for
treatment
Plant abandon and flows sent to Sand
Creek Satellite (Aurora new plant)
Same as local
Same as local
All flows sent to Denver/
Northside/Metro #1 system
(except Glendale) via
Cherry Creek/Goldsmith
Gulch interceptor
All flows via interceptor
to Metro //I for treatment.
Aurora plant abandoned.
Plant abandoned and flows
via interceptor to Metro //I
for treatment
Same as local but
but ammonia removal
facilities would be
added at later date
Same as local
Same as regional but
construction of inter-
ceptors delayed two
years
Same as regional but
construction of inter-
ceptors delayed three
years
Same as regional but
construction of inter-
ceptor delayed three
years.
-------
Table IV-P. (Continued). STATUS OF EXISTING/PROPOSED WASTEWATER COLLECTION AND TREATMENT FACILITIES
UNDER THE LOCAL, REGIONAL AND NO-ACTION ALTERNATIVES
Existing or
proposed facility
Status under
local alternative
Status under
regional alternative
Status under
no-action alternative
Clear Creek
7
South Platte
South Metro
Middle
Lower
Coors
Clear Creek Satellite
(also serving North
Table Mtn, Applewood,
and Pleasant View)
(6.56 ngd)
Wheatridge, Clear
Creek Valley, Arvada,
Crestview
Englewood/Littleton
(20 mgd)
South Lakewopd
Metro #1
Assumed to be upgraded to meet
secondary treatment levels with
nutrient removal to reduce effluent
NH3-S to 3 mg/1
Assumed to construct AWT plant meet-
ing effluent levels of 20 mg/1 each
for BOD and SS, 3 mg/1 for NH -N,
residual Cl to 0.05 mg/1, and FC
of 1000 MPN/100 ml. Effluent levels
may be more stringent depending upon
discharge/reuse.
Plants abandoned and flows via
interceptor to Metro #1 for treatment
The Englewood and Littleton plants
are not expanded in capacity but
NH -N and Cl removal facilities
are added. New AWT plant being
constructed near Englewood to handle
flows in excess of these two faci-
lities. AWT effluent levels
assumed at 20 mg/1 each for BOD^
and SS, NH3-N of 3 mg/1 and
residual Cl at 0.05 mg/1
Expand/upgrade to 'vS mgd AWT plant
and either discharge to South
Platte or reuse for urban
irrigation
No additional added capacity
above 185 mgd. NH.-N removal to
various levels depending upon
effluent discharge/reuse options
Same as local
Flows via interceptor to
Metro #1 for treatment
Same as local
Existing plants upgraded
to AWT levels (as shown
in local alternative) with
flows in excess of plants
capacities sent to Denver/
Northside/Metro if I system
Abandon existing plant and
transport all flows to
Metro #1 interceptor/plant
Capacity expanded to
260-270 mgd with NH -N
removal to various levels
depending upon effluent
discharge/reuse options
Same as local
Local alternative
delayed three years
Local/regional but
construction of inter-
ceptor delayed three
years
Addition of NH.-N and
Cl removal facilities
at existing plants
delayed one year.
Effluents used for
non-crop irrigation
rather than discharge
to South Platte (some
portion of effluent)
Maintain existing
plant with effluent
sent to Metro #1 for
further treatment.
Local alternative with
further expansion be-
yond 1985 delayed
-------
Table IV-P. (Continued). STATUS OF EXISTING/PROPOSED WASTEWATER COLLECTION AND TREATMENT FACILITIES
UNDER THE LOCAL, REGIONAL AND NO-ACTION ALTERNATIVES
Ba s in
Existing or
proposed facility
Status under
local alternative
Status under
regional alternative
Status under
no-netion alternative
<
Big Dry Creek
Coal Creek
Boulder Creek
South Adams County
Lower South Platte
Satellite Plant at
164th Avenue
(8.7 mgd)
Broomfield/Westminster
Erie, Lafayette,
Louisville 1985:
0.4 mgd, 1.3 mgd,
1.3 mgd; 2000:
1 mgd, 2 mgd, 2 mgd
Boulder/White Rocks
18 mgd
Expand/upgrade existing plant to
5-6 mgd with NH_-N removal.
Effluent at 20 mg/1 each BOD_ and
SS, NH -N at 3.5 mg/1, and FC at
200 MPN/100 ml. Residual Cl at
0.5 mg/1. Effluent discharge to
South Platte.
New plant to treat flows from
Brighton; Lower Thornton; and
1st, 2nd, and 3rd Creeks.
Effluent at 20 mg/1 each BOD-
and SS, NH -N at 3 mg/1, FC at
1000/100 ml, and residual Cl
of 0.05 mg/1. Flows from
Upper Thorton and NWSWDS to
Metro //I. Option to pump
some of plant flow to Big
Dry Creek plant
Big Dry/Westminster plant expand-
ed upgraded to 8 mgd with 20 mg/1
each BOD and SS, NH -N at
2.5 mg/1, FC at 200/100 ml, and
residual Cl at 0.5 mg/1. Plant
treats excess flows from Broomfield
and flows from Westminster and some
of Thornton. Discharge to either
Farmers Highline Canal or Big
Dry Creek.
Expand/upgrade existing facilities
to 20 mg/1 each BOD. and SS,
NH -N at 3 mg/1, FC at 200/100 ml
Add tertiary treatment via
percolation ponds with per-
colate to Boulder Creek.
Plant expanded to 3.75 mgd
by 1977 but abandoned by
1985 with all flows to
Metro //I.
All flows to Metro
Maintain current capacity
of Big Dry/Westminster
plant at 2 mgd, provide
NH_-N removal. Maintain
other plants at existing
capacity and excess flows
to Metro #1
Same as local
Same as local
Expansion to 5-6 mgd
delayed one year. No
NH--N removal provided
Local alternative with
construction of new
plant delayed four
years
Expand Big Dry/West-
minster to 5 mgd with
NH--N removal. Main-
tain other plants and
excess flows to Metro
#1.
Same as local but
expansion/upgrading
delayed
Same as local
-------
sultants, has made an extensive review of the various water quality
criteria necessary to satisfy various beneficial uses of the area's
surface waters while meeting the 1983 goals. Recent acitivities by
DRCOG in developing wastewater treatment strategies for the 208 plan-
ning areas have resulted in the assignment of four alternative classi-
fication levels of water quality according to groupings of eight pro-
posed water uses for the Denver area (Reference 261). Alternative
Classification 1 levels are governed primarily by primary-contact,
cold-water-biota and potable-supply water uses, and the alternatives
descend in levels of water quality to Alternative Classification 4
levels, which are primarily secondary-contact agriculture and wild-
life uses and which generally represent present water quality.
Recent activity with the 208 planning program has centered on
obtaining both citizen and internal task force review of the as-
signment of stream classifications for specific areas within the 208
planning area. These specific areas and the alternative classifi-
cation levels selected by the 208 Task Force following their review
of the Draft Wasteload Allocation Report (Reference 262), are shown
in Table IV-Q. Significant to the review of this table is the know-
ledge that the recommended 208 planning levels were based in part
upon the costs associated with providing the wastewater treatment
needed to meet each of the four levels and' that these costs in turn
were predicated upon meeting the levels during 7-day, 10-year low
flows, not historical average flows. It is likely that treatment ef-
ficiencies required, and hence the concomitant costs, would have been
lower had some average been selected for wasteload allocation analy-
ses rather than using low flows, and this would have had an effect
on the resultant recommended alternative classification levels.
Shown in Table IV-R are the water quality criteria suggested
as necessary and sufficient to meet the 1983 goals within the
study area.
The information presented in Table II-H of Section II indi-
cates that the only location within the study area that presently
consistently meets the water quality criteria established to meet
the 1983 goals presented in Table IV-R for all seasons is the up-
stream reach of the South Platte, above Chatfield Reservoir. The
upper portions of the remaining basins are, for the most part, well
within the 1983 goals except for the nutrients ammonia and phos-
phate, during all seasons; and fecal coliforms, during the spring
at Bear Creek/Morrison and Clear Creek/Golden. Thus, the background
quality of water entering the major basins within the study area is,
with the exception of nutrients, high. However, as can be seen
from the review of Table II-H, the water quality of the streams is
degraded as they pass through the lower portions of their respec-
tive basins, particularly with regard to nutrients and fecal
IV-62
-------
Table IV-Q. SELECTED ALTERNATIVE CLASSIFICATION LEVELS
BY SPECIFIC STREAM AND/OR STREAM AREA
Alternative
Classification Level
South Platte
Dartmouth Avenue to MDSDD #1 outfall 4a
MDSDD #1 outfall to Weld County line 2
Cherry Creek below reservoir 2
Sand Creek 4
Clear Creek below Golden 2C
Big Dry Creek below Standley Reservoir 3
Coal Creek - Highway 93 to mouth 2
Boulder Creek - 75th Street outfall to mouth 2
o
To consider potential water supply conflict with Brighton and
Thornton.
To consider water supply for South Adams.
Q
Alternative 1 to be kept open as an option
Source: Reference 2.
NOTE: Alt. 1, primary contact, cold-water viota, water supply;
Alt. 2, warm-water biota, water supply; Alt. 3., warm-
water biota, secondary contact; Alt. 4, Secondary
contact, agriculture,
coliforms. The 1983 water quality goals for these pollutants are
routinely exceeded throughout the year. For all locations, tempera-
ture criteria are met, on the average by season, except during the
winter, when the criterion for swimming is exceeded. However, this
activity is unlikely to occur during the winter season. Dissolved
oxygen levels are still relatively high throughout the major basins
during all seasons, with the exception of South Platte above Lit-
tleton during the summer. This may in part be due to the release of
IV-63
-------
Table IV-R. WATER QUALITY CRITERIA TO MEET 1983 GOALS
Parameter
Temperature
Minimum
Maximum
Dissolved oxygen
Total dissolved solds
Ammonia (NtU-N)
Phosphate (total)
Fecal coliform
15°C (for swimming)
20°C (for cold-water fishery)
30°C (for warm-water fishery)
35°C (for swimming)
5 mg/1 (for warm-water fishery)
7 mg/1 (for cold-water fishery)
2,000 mg/1
0.02 mg/1 (un-ionized)
0.1 mg/1
200 MPN/100 ml
Source; Reference 261.
low-level dissolved oxygen waters from Chatfield Reservoir during
the summer months, the reason for which is unknown at this time.
Levels of total dissolved solids, although below the suggested
levels for the 1983 goals in all major basins, do tend to increase
substantially from upstream in any basin, and within the Sand Creek
basin are above the level suggested for its use classification,
one of the uses being that of a water supply source for urban ir-
rigation.
It is within this general context that the three major waste-
water collection and treatment alterantives in this report were
developed and will be analyzed, in the following subsection, as
to their likely impacts upon water quality and the likelihood of
their meeting or approaching the 1983 water quality goals within
the context of the 208 draft plan for control of nonpoint sources
of pollutants. The status of existing or proposed wastewater col-
lection and treatment facilities within the study area's stream
basins is indicated in Table IV-P. In addition, it should be noted
that there is the likelihood that wastewaters from the City of
Golden will be treated at an advanced treatment facilitity, which
IV-64
-------
would allow the City of Golden the option of reusing the effluent
in the upper portion of Clear Creek.
The Local Alternatives
The upgrading of the Morrison Sewage Treatment Plant (STP) to
provide ammonia removal is expected to provide some reduction in
this point source loading to Bear Creek. However, as can be observed
in Table II-I, point sources do not account for a significant portion
of the ammonia loading in the basin, particularly in the upper por-
tion. It appears necessary to provide a fairly high degree of non-
point source control in order to reduce loadings of all constituents
which are adversely affecting the Bear Creek basin, as can be noted
in Table II-H.
On Cherry Creek above the reservoir, the option for an advanced
waste treatment (AWT) plant exists. This plant would have a very
high level of treatment when discharging to Cherry Creek and thence
to the reservoir. However, this would occur only during non-irriga-
tion seasons. At other times, effluent would only be treated to the
levels necessary for agricultural irrigation/reuse. In theory, if
the additional flows during winter into the reservoir were equalled
by additional downstream discharges from the reservoir, the flow in
Cherry Creek would about double in 1985 and increase another 50 per-
cent in 1995. This coupled with Ammonia removal at the Glendale
plant would improve water quality levels throughout lower Cherry Creek.
Phosphate would remain a problem. Therefore, any augmentation of
creek flow would be limited to winter months. Beneficial uses of
secondary contact recreation would be limited to that portion of
Cherry Creek between the reservoir and Glendale as the remainder of
the creek is channelized with vertical concrete walls, and access
is limited.
The provision of AWT facilities at the present Aurora STP site
is expected to result in a significant reduction in point-source
loadings of ammonia in Sand Creek. However, by removing the effluent
flows from the stream and transferring water to Quincy Reservoir, it
appears that stream flows in Sand Creek would then be too low to
provide secondary-contact recreation opportunities. The question
of water rights and transfer appears to be of major importance in
this basin. Nonpoint source controls would then become very impor-
tant in this basin because it is likely that stream flows necessary
for secondary-contact recreation would occur only during the spring
season, when storm runoff augments the base flows.
The provision of AWT facilities on Clear Creek (Golden and Sate-
llite plants), along with improved treatment at Coors and the re-
IV-65
-------
moval of effluent flows at the STP's in the lower portion, would
vastly improve the water quality of Clear Creek. As was indicated
in Section II (Existing Water Quality), this basin is significantly
impacted by point-source loadings, particularly by BOD^, ammonia
and phosphate. It appears, however, that in order to meet, or at
least approach 1983 water quality goalds, provision for phosphate
removal at point sources will be necessary under the local alter-
native, particularly if the AWT facilities discharge to Clear Creek.
Were the Golden and Clear Creek Satellite plants to reuse the ef-
fluents for irrigation, phosphate removal might not be necessary
unless irrigation return flows were high in phosphates. Under the
latter option, the major point source on Clear Creek would then be
the Coors STP, which because of its major contribution in flow
volume during the summer would likely have to provide phosphate re-
moval in order for Clear Creek to approach 1983 goals.
Another major problem area, the portion of the South Platte be-
tween Littleton and 38th Avenue, would be alleviated by the up-
grading of treatment at the Littleton and Englewood STP's in addi-
tion to the combined AWT plant at Englewood. As was noted in Table
II-H, point-source loadings in this portion of the South Platte are
significant with regard to BODr, ammonia and phosphate. Once again,
however, phosphate removal in addition to planned reductions in
BOD^ and ammonia appear necessary in order to approach 1983 goals.
Within the middle portion of the South Platte, the expansion
and upgrading of the South Lakewood STP will have a positive, al-
though less significant, impact upon improving water quality in
the South Platte. The removal of ammonia from the plant's effluent
would benefit the South Platte waters, but it is unlikely that
phosphate removal for South Lakewood would be warranted because of
the dominance of nonpoint sources of phosphate in this area. This
portion of the South Platte is clearly dominated by nonpoint sources
for all water quality parameters (see Table II-H), and any addi-
tional expenditures at the South Lakewood STP about secondary treat-
ment with ammonia removal would not be likely to prove cost-effec-
tive. Highly effective non-point source controls would be needed
to achieve 1983 goals.
Within the lower South Platte, existing water quality is most
clearly dominated by point sources, and most particularly by
MDSDD #1. The upgrading of effluent quality at Metro and South
Adams County STP's would improve water quality above Henderson, and
the satellite plant serving the Brighton/Thornton area would also
have a positive impact below Henderson. However, because of the
very substantial contribution of loadings from Metro, particularly
in total dissolved solids, BODr and Ammonia, it appears that diver-
IV-66
-------
sion of a sizeable portion of Metro's effluent to Burlington Ditch
for irrigation reuse would not only have a greater positive ef-
fect upon water quality in the South Platte but might also be cost-
effective in terms of degree of ammonia removal and the possible
elimination of necessary phosphorus-removal facilities.
Under the local alternative, the remaining facilities in the
Big Dry, Coal and Boulder Creek basins are to continue discharging
to their respective streams with high levels of effluent quality
for protection of stream quality. The option to discharge effluent
from Big Dry STP to the Farmers Highline Canal for reuse as irriga-
tion water appears to be a better use of the basin's water (Reference
261). Provided the necessary transfer of water rights can be a-
rranged, this option also appears to best protect the water quality
of Big Dry Creek; however, significant stream flow reduction is likely.
From an evaluation of information presented in Table IV-P
and from the Wasteload Allocation Report (Reference 261), it ap-
pears that the levels of point-source treatment proposed in the
local alternative may provide stream water quality at Classifica-
tion Level 3 (warm-water biota and secondary-contact uses). As can
be noted from Table IV-Q, this alternative, then, provides in-stream
water quality which is lower than that suggested for most of the
study area basins, i.e., Classification Level 2. Also, it is un-
likely that the 1983 goals specified in Table IV-Q would be met by
these point-source controls, particularly in view of existing back-
ground levels of ammonia and phosphate caused primarily by non-
point pollution sources. However, Classification Level 2 (warm-
water-biota and water-supply uses), that is desired in the more
critical areas of the Cherry Creek, Clear Creek and lower South
Platte basins, may possibly be met during periods of average daily
streamflows, particularly if sizeable portions of Metro's effluent
were diverted to Burlington Ditch and the Clear Creek and Cherry
Creek satellite plants were constructed to produce effluent at
quality levels sufficient either for desired stream water quality
or for indirect reuse.
The Regional Alternative
In the Bear, Cherry, Sand and Clear Creek basins, only the
Morrison, Glendale and Coors STP's would be upgraded, while all other
wastewater would be transported for eventual treatment at the Metro
plant. However, the resultant reductions in base streamflow in
Cherry and Sand Creeks would likely reduce the potential for secon-
dary-contact recreation to the spring season alone, when nonpoint
source control would become necessary. In the Clear Creek basin,
the reduction in streamflow might impair water rights of irrigation
diversion flows. The overall impact would be the basin-wide re-
IV-67
-------
duction in Clear Creek base flows, resulting in a greater need
for nonpoint-source controls within the basin that might other-
wise be necessary to compensate for the loss of dilution avail-
able with higher base flows.
With the portion of the South Platte immediately below Little-
ton the existing Littleton and Englewood STP would be upgraded,
with all flows in excess of the plant's capacities sent to Metro.
There would be reductions in point-source loadings, particularly
with regard to ammonia and BOD,-, and the transport of excess flows
to Metro would further reduce the impacts of point sources on the
water quality of South Platte in this area.
By transporting all domestic wastewaters from the middle
portion of the South Platte to Metro for treatment, the impact of
these point sources would be removed. However, as can be noted
from Table II-I, the major contribution of pollution in this por-
tion of the South Platte stems from nonpoint sources. Recognizing
that nonpoint source pollution would probably occur more frequently
during the spring, the improvement in water quality for the South
Platte in this area would likely be more noticeable during the
summer season. Loss of the discharge from South Lakewood would
be insignificant as it would contribute only 10 percent of low flow
in the South Platte. This, coupled with the provision of South
Platte stream bank parks, would increase the opportunity for
secondary-contact recreation during the summer, particularly if
upstream water quality improved in the portion of the South Platte
immediately below Littleton.
With Metro facility expanded to handle all the flows diverted
from the other basins, the lower South Platte basin would experience
the flow of a very large point source at its upper portion, with other
point sources downstream from Metro eliminated. This configuration,
as compared to three smaller point sources located along the South
Platte from Commerce City to Brighton under the local alternative,
might result in considerably reduced stream water quality in a stretch
of the South Platte below Metro (in comparison with the more uniform
level of water quality obtainable under the local alternative),
although there would be some downstream recovery. The extent and
degree of this reach having reduced water quality is unknown at this
time. It is likely, however, that under the regional alternative
equal or greater consideration would have to be given to discharging
a significant portion of Metro's effluent to Burlington Ditch, not
only to protect water quality and downstream water supply uses.of
the South Platte but also to reduce the sizeable expenditure of funds
likely to be necessary for the reduction of ammonia, and possible
phosphate, to levels acceptable for stream discharge.
IV-68
-------
The configurations and probable water quality impacts for
Coal Creek and Boulder Creek would be the same as for the local
alternative, i.e., the improvement of water quality in streams,
the base flows from which come principally from STP effluents.
However, the option of reusing effluent from the Big Dry Creek
STP for irrigation purposes in the Farmers Highline Canal is
not included in the regional alternative, and basin flows are
transferred to Metro rather than being utilized to maintain
streamflows in Big Dry Creek.
Unlike the local alternative, there have been no definitive
studies with regard to the overall impact of the regional alter-
native on the study area's water quality. The individual stream
basin impacts of the various facility plans have been discussed
above, and the overall impact may be assessed in general. Al-
though most point sources are removed from the Sand, Clear and
Middle South Platte basins, thus reducing their adverse impacts
upon these streams (Table II-I), by doing so the basins are rendered
more susceptible to fluctuations in base flow and to influences
of non-point sources which, as noted in Section II, are signifi-
cant within the study area, It is therefore likely that the con-
trol of non-point sources in these basins will become more impor-
tant in the effort to approach 1983 water quality goals. The im-
pact of point sources in the lower South Platte becomes more im-
portant for the Metro facility than in the local alternative, as
discussed above. It is likely that in order to approach 1983
water quality goals for the lower South Platte, the Metro facility
either would have to provide a very high level of treatment or
would have to divert a very significant portion of its effluent
to the Burlington Ditch.
The No-Action Alternative
As can be noted from Table IV-P, the overall status of the no-
action alternative is to maintain the existing plant configurations
for the next several years, after which time flows in the Sand and
Cherry Creek basins and in the lower portion of Clear Creek basin
would be sent to Metro, and satellite plants would be constructed
in the Clear Creek and lower South Platte basins, with expansions
of the Big Dry Creek plant to handle more of its basin's waste-
waters. The South Lakewood plant would sent its effluent to Metro
for further treatment; the Englewood/Littleton facilities would
utilize some portion of their effluent for non-crop irrigation;
and the South Adams STP would be expanded to handle more of its
basin's wastewaters.
IV-69
-------
The immediate impact of this alternative is the continuing
degradation of water quality in the study area; i.e., the water
quality will remain essentially at Classification Level 4 (secon-
dary-contact and agriculture water uses), Following the period
of upgrading, expansion and routing of wastewater flows, as des-
cribed earlier, the impact of point sources in the basins within
the study area would be reduced, particularly in the Sand, Cherry
and middle South Platte basins.
Although no rigorous assessment of the stream water quality
that will result from the implementation of this alternative is
available, it appears that the alternative does combine some of
the best features of the two previous alternatives. There is not
such a heavy reliance upon treating most wastewater flows at the
Metro facility; the Big Dry Creek basin maintains its option of
irrigation reuse of its effluent; point sources are treated in
the South Metro portion of the South Platte, with some portion of
the effluent reused for irrigation; and the impact of point
sources in the lower South Platte is reduced and spread out
rather than being concentrated in one portion. However, point
sources will still contribute to water quality problems in the
upper portion of the Clear Creek basin unless treatment levels
at the satellite plant are such that either some form of effluent
reuse can be implemented or downstream water quality is protected.
Under this alternative, non-point sources become the influencing
factor in the Sand, Cherry and middle South Platte basins. It is
likely that resultant stream water quality within the study area
under implementation of the no-action alternative will approach
that of the local alternative, for the possible attainment of
Classification Level 3 (warm-water biota and secondary contact
recreation uses).
The principal differences from the no-action alternative to
the local alternative is a likely delay of 3 years in the imple-
mentation of point source water quality improvements and a shift
in the burden of paying for these improvements from the Federal
Government (national taxpayer) to the local government and
local taxpayers.
Summary
Utilizing information from Section III of this report and from
Reference 261, Table IV-S indicates the anticipated 1985 nonpoint
source loadings by basin and the resultant point-source loadings
within the same basins after implementation of each of the three
major alternatives. It should be noted that the point source load-
ings assume discharge to the respective creeks, with the exception
IV-70
-------
of the Sand Creek Satellite plant, as mentioned previously, which
will discharge its entire effluent to Quincy Reservoir under the
local alternative, and Boulder Creek, which discharges to perco-
lation ponds. The levels of treatment for the wastewater facili-
ties were noted in Table IV-P except for Metro, which is assumed
to discharge a secondary level effluent (i.e. BOD^ of 30 mg/1 and
Ammonia of 3 mg/1). Phosphate levels in all treatment plant ef-
fluents are assumed at 8 mg/1. The Boulder Creek plant, which
will discharge its effluent to percolation ponds, is assumed to
have a negligible effect upon Boulder Creek.
It can be seen by comparing Tables IV-S and II-H that non-
point sources of pollution are expected to increase throughout
the study area by approximately 49 percent for each of the four
parameters shown in Table IV-S. This increase is a direct conse-
quence of further urbanization in the Denver Region. Those basins
with the largest increase are Bear Creek (200-220 percent), Cherry
Creek (BOD^ and Phosphate 75 percent, Ammonia 100 percent), Clear
Creek (60 percent), and Lower South Platte (70 percent). Pollu-
tants from point sources would also be expected to increase as a
result of growth, but treatment by wastewater treatment plants
may negate or offset growth effects, and/or pollutant loadings
from point sources may be minor compared to nonpoint loadings.
For example, by 1985, on Clear Creek under the local alternative,
the nonpoint loading for BOD5 will increase by 60 percent, whereas
the point source loading will decrease 30 percent compared to 1972.
Thus, while point sources dominated total loadings in the Clear
Creek basin in 1972, non-point loadings will dominate in 1985.
This would be true even if nonpoint loadings were reduced by one-
third under an effective nonpoint source control program.
An examination of the total basin-wide loadings in Table IV-S
indicates that the majority of BOD,-, Ammonia, and phosphate will
originate from point sources. However, if those loadings in the
lower South Platte, principally from the Denver Northside/Metro
complex are deleted, the only pollutant still dominated by point
sources is phosphate. All other pollutants are dominated by non-
point sources. It must be remembered that nonpoint sources of
pollutants in most cases only affect water quality when they enter
a stream via some runoff event such as snowmelt or precipitation.
Thus, their contribution is not constant as are the contributions
from point sources. Nevertheless, the Bear, Cherry, and Sand Creek
basins as well as the portion of the South Platte flowing through
Denver proper are dominated by nonpoint sources of pollutants now
and in 1985, and would remain so even if a 35 percent reduction
of nonpoint loadings were achieved in 1985. The upstream portion
of the South Platte would be dominated by point sources, namely
IV-71
-------
Table IV-S. ANTICIPATED POINT AND NONPOINT SOURCE LOADINGS IN THE YEAR 1985 BY STREAM BASINS
(pounds per day)
Basin
3iar Creek
Cherry Creek
Sar;d Creek
Cl^ar Creek
South Platte
South Ketro
H -idal£
1 Loi.-ar
Subtotal
Big Dry Creek
Coal Creak
Boulder Creek
Total
Nonpoint
source
235
360
560
540
280
800
540
3,315
230
170
440
4,155
Local
2
225 (90)
0
390
575
55
3,850
5,097 (4,962)
100
75
-
5,272 (5,137)
Ni-:3-s
Point Source
Regional
2
25
0
225
490
0
4,770
5,512
90
75
-
5,677
No-action
2
25
0
390
575
0
4,290
5,282
125
75
-
5,482
Nonpoint
source
210
320
530
490
280
750
530
3,110
200
150
410
3,870
Local
5
600 (87)
0
1,560
1,470
150
10,300
14,085 (13,572)
330
200
-
14,615 (14,102)
poZ
Point Source
Regionao.
5
70
0
1,130
1,240
0
12,700
15,145
240
200
-
15,585
No-action
5
70
0
1,560
1,470
0
10,400
13,505
330
200
-
14,035
>;ote: Values in parenthesis for Cherry Creek - Local Alternatives are those resulting from high levels of
tertiary treatment at the Cherry Creek Satellite plant.
-------
Littleton/Englewood, for BOD^, Ammonia, Phosphate, and TDS. The
Clear Creek basin will become dominated by non-point sources for
BODcj and Ammonia, but remain dominated by point sources for phos-
phate and for TDS. A 35 percent reduction in non-point sources
as contemplated in the 208 plan, would not change this conclusion
except that the contributions of Ammonia would be about equally
balanced between point and nonpoint sources.
One particular point should be noted: in the local alter-
native, the Cherry Creek Satellite plant would appear to contribute
significant loads of BODr, NHg-N and PO, to its basin were the ef-
fluent to be discharged year round. The discharge levels for the
plant assumed under this alternative for these parameters were
20,3 and 8 mg/1, respectively. Were these levels reduced to 5 mg/1
BOD5, 1 mg/1, NH3-N and 0.3 mg/1 P04 (tertiary treatment level 14,
as noted in Reference 262) , the Cherry Creek basin point source
loadings would be reduced to 430 pounds per day BOD^, 90 pounds per
day NHg-N and 87 pounds per day PO^. It is therefore likely that
the incorporation of tertiary treatment at the Cherry Creek sate-
llite plant, with the effluent discharged only during the winter/
non-irrigation season, would significantly enhance the Cherry
Creek basin.
There are two basic approaches to reducing the impact of Metro's
discharge on the lower South Platte. First is reducing the amount
of the discharge, and second is improving effluent quality with
higher levels of, wastewater treatment. The first approach is a
limited possibility in that increased amounts of effluent may be
diverted to agricultural irrigation via the Burlington Ditch during
the irrigation season. If the amount of effluent discharge to the
South Platte were reduced to 15 million gallons per day (mgd) under
the local and no-action alternatives or 25 mgd under the regional
alternative, point sources for BOD- and Ammonia would then be com-
parable to nonpoint sources. However, point sources of phosphate
would still be two to three times nonpoint loadings.
Upgrading of effluent quality through tertiary treatment to
levels of 5 mg/1 6005, 1 mg/1 Ammonia, and 0.3 mg/1 phosphate
for the Lower South Platte basin, Metro plant, would have the follow-
ing results. Under the local and no-action alternatives, EOD^
loadings from point sources would be comparable with non-point load-
ings. Point sources for Ammonia and Phosphate would be two and
three times non-point loadings. Under the regional alternative,
point sources would still greatly dominate.
TV-73
-------
As mentioned previously, the implementation of any of the
three major wastewater collection and treatment alternatives is
likely to result in in-stream water quality approaching Classi-
fication Level 3, that being the use of stream waters for secon-
dary-contact recreation and protection of warm-water biota. Pre-
sent study area water quality levels are at Classification Level
4, secondary-contact and recreation uses. Previous investigations
under 208 planning wastewater alternatives nearly identical to the
local alternative presented herein have indicated the anticipated
percent of the time that Classification Levels 3 and 4 cannot be
met by point-source controls alone. Table IV-T and IV-U indicate,
respectively, these time percentages during the year when the
present (Level 4) and expected future (Level 3) water quality will
not be met for the local and no-action alternatives, The imple-
mentation of the regional alternative is expected to lower the per-
centages in the Cherry, Sand and Clear Creek basins and to increase
them in the lower South Platte (MDSDD //I toWeld County line).
A review of these two tables indicates that as desired water
quality in the study area increases, nonpoint source controls be-
come more necessary. Also, nonpoint source problems appear to be
more pronounced in the Sand, Cherry and middle South Platte basins
and, to a lesser extent, in the lower portions of the Bear and
Clear Creek basins.
In the metropolitan area, the effect of non-point sources
on meeting stream standards is considerable. The 208 plan has
identified two major parameters, phosphate and fecal coliform,
from non-point source runoff that could constrain the attainment
of the "swimmable" criterion for Front Range streams without some
form of non-point source control. Assuming advanced treatment
of the point sources, there are fewer water quality limitations
to attaining the "fishing" and non-contact recreation criteria,
as shown in Table IV-V.
It has been noted in the 208 planning studies and Tables
IV-T and IV-U demonstrate, that even the most stringent control
of effluent quality from point sources will not be sufficient
for meeting 1983 water quality goals, and that some nonpoint
source control will be necessary.
IV-7 4
-------
Table IV-T. PERCENT OF TIME DESIRED WATER QUALITY CANNOT BE ACHIEVED
BY POINT SOURCE CONTROLS ALONE. CLASSIFICATION LEVEL 4
~-j
Ui
Stream and location
South Platte: Headwaters
tothatfield Dam
South Platte: Chatfield
Dam to Dartmouth Ave.
South Platte: Dartmouth
Ave. to MDSDDfll
South Platte: MDSDD01
to Weld County Line
Bear Creek: Headwaters
to Bear Creek Dam
Bear Creek: Bear Creek
Dam to Mouth
Cherry Creek: Headwaters
to Reservoir
Cherry Creek: Reservoir
Cherry Creek: Reservoir
to Mouth
Clear Creek: Headwaters
to Golden
Clear Creek: Golden to
Mouth
Sand Creek: Headwaters
to Mouth
u
u
4J
c
o
u
14
0)
1^
Ou
0
0
X
X
100
100
X
40
X
100
X
X
u
aj
u
Q
O
U
p->
•O
g
u
V
0
0
40-50
40
5
50
0
0
50
0
10-40
60
a
3
3
O
•H
<*
•*
0
0
40-50
40
5
50
0
0
50
0
10-40
60
01
4J
O
•H
J3
a
§
•a
o
o
5
5
X
X
0
X
X
X
X
X
X
X
0)
4J
o
•H
•°
01
4J
S
B
•*
X
X
0-10
X
X
5
X
0
X
X
0-5
X
1-1
a.
a.
m
u u
01 0>
5 §
o "c
iH O
j^ M
3 U
&» '^
0
0
X
X
15
100
0
0
X
70
X
X
o.
0.
01 M
01
0) CO
4-> 9
7 a>
u
0 <»
^ 3
(S "-*
0
0
X
X
5
50
0
0
X
0
X
X
9
a
§
01
IM
•H
3
1-1
*
0
0
40-50
40
5
50
0
0
50
0
10-40
60
NOTE; X - Not a designated use
SOURCE: Ref. 1
-------
Table IV-U. PERCENT OF TIME DESIRED WATER QUALITY CANNOT BE ACHIEVED
BY POINT SOURCE CONTROLS ALONE. CLASSIFICATION LEVEL 3
7
Stream and location
South Platte: Headwaters
to Chatfield Dam
South p'latte: Chatfield
Dam to Dartmouth Ave.
South Piatte: Dartmouth
Ave. to MDSDD//1
South Platte: MDSDDtfl
to Weld County Line
Bear Creek: Headwaters
to Bear Creek Dam
Bear Creek: Bear Creek
Dam to Mouth
Cherry Creek: Headwaters
to Reservoir
Cherry Creek: Reservoir
Cherry Creek: Reservoir
to Mouth
Clear Creek: Headwaters
to Golden
Clear Creek: Golden to
Mouth
Sand Creek: Headwaters
to Mouth
u
M
*J
a
0
o
H
0.
0
0
X
X
100
100
X
40
X
100
X
X
1
Secondary contact
0
0
40-50
40
5
50
0
0
50
0
10-40
60
Agriculture
0
0
40-50
40
5
50
0
0
50
0
10-40
60
Cold water biota
5
5
X
X
0
X
X
X
X
X
X
X
a
o
•H
01
n)
g
X
X
0-10
5-15
X
5
X
0
X
X
0-5
15
Public water supply
(Groundwater)
0
0
X
X
15
100
0
0
100
70
80
X
Public water supply
(Surface water)
0
0
X
X
5
50
0
0
X
0
10-40
X
c
•r4
IV
u
CO
ID
•H
•0
•H
0
X
X
5
50
0
0
50
0
10-40
60
NOTE: X - Not a designated use
SOURCE: Ref. 1
-------
Table IV-V. CONTROL REQUIREMENTS FOR POINT AND NONPOINT SOURCES
Pollutant
Principal Stream
Use Affected
Control Requirements
f
Phosphate
Annum ic
Kitrate
TDS
Fecal Coliform
Fecal Streotocci
Dissolved oxygen
levels
(BOD, nitrifi-
cation)
Body Contact
Fishery
Water Supply
Fishery
Agriculture
Water Supply
Body Contact
Fishery
Will likely require a combination
of point and non-point source
controls
Can currently only be effectively
removed from point sources.
Can be most effectively controlled
at point sources.
Can be effectively controlled
through non-point source programs.
Must be approached from both
point and non-point sources to-
gether.
Largely a function of point source
control on a sustaining basis and
of non-point source control for
storm-related events. Non-paint
source control cannot make up for
a lack in point source control.
Chlorine
Fishery
Point source control.
-------
GROWTH-INDUCED IMPACTS ON THE REGION'S ENVIRONMENTALLY SENSITIVE AREAS
Wastewater collection and treatment is one of several basic ser-
vices local government provides to serve the needs of its citizens.
Planning to accommodate a future population and its need for wastewater
treatment and disposal is a prudent and responsible function exercised
by local governments. Construction and operation of these facilities
in accordance with plans to accommodate future growth must be considered
a contributing factor to the environmental consequences of future growth.
The same is true for other services such as highways, schools, and water
supply. On a regional basis, it is rare that the provision or lack of a
single "municipal" service stimulates or constrains regional growth, and
can be considered the dominant factor in growth-related environmental im-
pacts. It can, however, influence development patterns. The purpose of
this section is to summarize the impacts of changes expected to occur in
the region as a result of the population increases and resultant develop-
ment patterns projected for the year 2000 for which the facility plans
and the Clean Water Plan were developed. A more complete assessment of
these impacts may be found in Appendix B.
Climate
Construction activities randomly located through the region
will often be a factor in the local severities of Chinook wind episodes
by providing particulates that can be blown downwind from the construc-
tion site to affect traffic, equipment, structures and crops. The
significance of this impact will range from that of a nuisance to that
of a hazard. Further development in the wind corridors of the South
Platte River and Clear Creek valleys will increase the potential for
wind damage in these areas. Early morning traffic problems ranging
from slow-downs to chain-reaction accidents will increase due to radi-
ation fog as traffic volumes continue to grow in response to suburban
growth.
Geology
Grading of undulating natural landscapes for urban development
can drastically modify landforms, change drainage patterns and alter
visual appearances. Grading impacts can be especially significant
in a local area where massive cuts and fills are made for roadbuild-
ing and hillside terracing, and in floodplains where protective de-
vices such as channelization, diversions and in-stream structures
are constructed. On a regional scale, these activities are likely
to have cumulative impacts on water quality. However, gross, visual
land form characteristics will not be radically altered. Urban de-
velopment will occur near unique and significant geological structures
and formations which will threaten many of them with over-use and
vandalism. The region's geological hazards to development are gener-
ally local in nature and do not pose any region-wide threats to ur-
ban expansion.
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Soils
Current reports are that due to the effects of the current drought,
many Colorado fanners on the plains are turning under their winter
wheat crops which is leaving the dry ground surface exposed to the
season's high velocity winds. Wind erosion can significantly reduce
or destroy land's agricultural production capabilities. In terms of
soil loss, however, water erosion is usually a more significant re-
gional impact of urban expansion than wind erosion. Construction
sites left exposed to precipitation and run-off experience sheet ero-
sion, rilling and, at times, gullying. All of these can clog drain-
age improvements; alter the drainage net by added streambank scouring,
turbidity, siltation and sedimentation; increase receiving water tem-
perature; and reduce chemical and biological water quality. These
impacts can have cumulative impacts on the region's drainage basins
and water quality.
Hydrology
Urban expansion can impact sensitive hydrologic features in-
cluding wetlands/marshes, floodplains, groundwater and lakes in three
main ways. These include: (1) encroachment into or elimination of
the feature, (2) change in the amount and distribution of water flow-
ing to or through the feature and (3) change in the quality of water
flowing to or through the feature.
Construction of buildings, roads and bridges together with re-
grading for development can result in encroachment into or elimina-
tion of wetlands/marshes, lakes and natural floodplains. The proxi-
mity of development can affect both the flora and fauna of the hydro-
logic element. Development can alter the extent of the flood hazard
area limits through alteration of the conveyance capacity of the na-
tural water course. Unwise occupation of the floodplain can serious-
ly increase the potential for flood damage.
Development can cause an increase in the base flow of water reach-
ing wetlands/marshes, lakes and floodplains, and the flora and fauna
may be affected. Lawn irrigation return flow, interception of the
groundwater by storm and sanitary sewer systems, and leaky water dis-
tribuiton systems may be responsible for the increased flow. Develop-
ment may cause a decline in the recharge to the groundwater table
through occupation of a recharge area such as that in the southwest
portion of the region through decreasing infiltration because of im-
pervious cover, and through elimination of agricultural irrigation in
the area. Development tends to increase the peak rate, volume and
frequency of flooding both within and without the floodplain. The
extent of increase tends to be larger for the more frequent floods
than for rarer ones. These changes can cause greater erosion within
steep floodplains and may affect the vegetation that can be main-
tained.
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Development is likely to produce a decline in water quality
reaching the hydrologic features. This can result from automobile
wastes, fertilizers, pesticides, sewage and sediment. Poor water
quality greatly speeds up the natural eutrophication process of
lakes and can affect the flora and fauna of lakes, wetlands/marshes
and floodplains.
The various hydrologic features such as floodplains, lakes,
groundwater, or marshes can also affect development. Any floodplain
development can be unwise, particularly along those stretches of the
upper portion of Bear Creek, Clear Creek and the upper portion of the
South Platte River which experience periodic flashflooding. The aes-
thetic quality of lakes may provide the interesting focal points a-
round which developments are planned. A reliable groundwater supply
may be one consideration in the feasibility of particular developments.
Wetlands/marshes within the study area are generally not viewed as
assets but may affect development through creation of the need for
drainage projects to dry them up.
Biology
The conversion of rural lands to urban uses typically requires
flood control measures for local watercourses. Channel straighten-
ing, removal of reparian vegetation, paving of streambanks and co-
lonization by weeds severely reduce habitat diversity. The soils
erosion impacts discussed earlier affect aquatic habitats by filling
in rough stream channel bottoms with silt which eliminates the physi-
cal niches necessary to benthic organisms, thus eliminating the or-
ganisms themselves. Continuing and future aggregate mining necessary
to construction activities is likely to entail channel disturbances
and modifications, streamside vegetation removal, and discharges of
wash water from gravel processing operations. Construction across
riparian zones severs the continuity of this habitat thereby dis-
rupting wildlife movements through it. Development around pond and
marsh areas often disturbs the local habitat quality. The opening
of rural and wild lands for residential and increased recreational
uses creates pressures on wildlife and their habitats.
Development along the foothills and mesa areas may infringe upon
critical wintering areas typically used by deer and elk. Some cur-
tailment of deer and elk feeding range may occur in the eastern
boundary near Cherry Creek Reservoir and to the west in Douglas County.
Animal and bird migrations through the lower foothill area may also
be disturbed. As indicated on Map F, several areas have been recog-
nized as ecologically significant due to unique geologic formations,
soil types, plant and animal communities and other factors. Develop-
ment and recreation pressures on these areas may not only degrade
the habitats or affect the surrounding environments, but which also
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cumulatively reduces the overall environmental quality of the region.
Areas of particular concern due to urban expansion as noted by com-
parisons of the Projected Land Use By the Year 2000 Map (Map I) a-
gainst the Biologically Sensitive Areas Map (Map F) are: (1) the
Nature Conservancy in northwest Denver, (2) the Ken Caryl-Johns Man-
ville Ranch, (3) the Marshall Mesa and (4) the White Rock area near
Boulder.
Human activities greatly increase the wildfire potential parti-
cularly on slopes of 30 percent or greater where the fire hazard is
critical. Construction and maintenance activities on steep slopes
and the resultant slash, felled trees and other inflammable litter
significantly increase this potential.
Energy
The 1975 population of the Denver Region constituted about 57 per-
cent of the population of the State of Colorado. By 1985 it will con-
stitute perhaps 60 percent, and by 2000 about 54 percent of the state
population. The Denver region's share of statewide energy consump-
tion is estimated to be on the order of 64-68 percent at the present
time. Natural gas shortfalls, amounting to 15-20 percent within five
years> are expected to begin in the Denver region during 1978-79. The
demand for natural gas by the Denver region may adversely affect the
rural areas of Colorado as rural areas are dependent on liquid pro-
pane which is manufactured from natural gas. There will be an in-
creased reliance on and demand for electric power. After 1980, if
scheduled power plants are delayed significantly, some brown-outs or
load reduction and shedding will occur. The increased demand for
electrical power will probably be met with coal-fired power plants
which will necessarily increase Colorado's coal production. Conse-
quently, beginning in the 1980's, conflicts will arise between muni-
cipal and agricultural water users in the Denver region, and energy
industries over available water supplies. Adverse air and water
quality impacts are also likely. Reference 970.
Regional demand for petroleum-based fuels will increase with in-
creased population. This increased demand will be limited to some
degree by increased vehicle fuel economy and higher fuel prices. Al-
though there will still be a net increase in consumption, petroleum-
based fuels will be a smaller part of overall basic fuel use.
Aesthetics
Growth in the Denver region could lead to a degradation of many
qualities which have created Denver's attractiveness and desirability.
Some of the qualities that would probably be adversely affected in-
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elude; (1) open spaces, wetlands and other natural areas, (2)
wildlife, (3) scenic views through high-rise construction and air
quality related visibility obstruction, (4) air quality, (5) noise
levels, and (6) relaxed lifestyle,
Outdoor Recreation Sites
Regional growth will require development and recreation sites
beyond those acquired to date, The growing needs of populace will
not be met as the land area per capita for parks will decrease 36%
from 15.2 acres per capita in 1970 to 9.9 acres per capita in 2000,
Park overuse and facility vandalism will continue and intensify
throughout the region particularly in those areas having a high per-
centage of children and young people. This will be especially true
in new suburban areas where there is a general predominance of young
families. As these suburban areas age, the populations should begin
to mature and the incidences of vandalism should somewhat decrease.
Land Waste Treatment Sites and Wastewater Reuse
Until a decision is made on the West Adams County Sludge disposal
site, the Lowry Bombing Range sludge disposal activities will continue
and existing problems could worsen due to the high sludge application
rates. However, the anaerobic digesters now under construction at the
MDSDD No. 1 plant will reduce the short-term possibility of a worsen-
ing situation. If the West Adams County site is not approved due to
some unforeseen environmental or legal problems, some new disposal
scheme for the Lowry site might be adopted which could continue the
present controversy. This controversy has resulted from a basic con-
flict between the established disposal use and the adjacent and grow-
ing residential uses.
As was indicated in an earlier chapter discussions, development
of new land application systems for wastewater treatment under the
ownership and operational control of Denver area sanitation districts
is considered difficult. Monitary costs of land acquisition and water
rights problems have made these systems look unfavorable by comparison
to conventional treatment. In some cases the wastewater operating a-
gencies (e.g. Metro) do not have ownership of the waters they are
treating. However, implementation of a Metro-operated land application
system presents innumerable institutional difficulties.
Development of new lands for irrigation also run afoul of existing
water rights. For a municipality owning tributary water, a land appli-
cation system that consumed additional South Platte water, would re-
quire the purchase of additional water by the municipality to "make
up" the lost consumed water. Cities that own West Slope non-tributary
water do generally have the right to reuse the water.
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From EPA's perspective, water quality benefits are paramount,
especially where potential construction grant funding is involved.
From the point of view of the municipalities, the most financially
beneficial use of these waters and development of new domestic
water supplies may be the most important criteria. From the per-
spective of downstream irrigation, water supplies should be neither
diminished in quality or quantity. Additionally, State water
quality priorities have favored protection of high-quality moun-
tain streams (much of which is on the Western Slope) over plains
streams that vary widely in seasonal flow and have been heavily
contaminated by municipal and agricultural use. Thus, defining
"benefits and impacts," particulatrly for water quality is no easy
task.
A number of important interrelated considerations must be kept
in mind in discussing reuse potential in the water-short Front Range
area:
a. The region is still growing rapidly in population. Considera-
tions of new municipal water supplies for growth is necessary.
b. All of the water now in the South Platte basin is being used;
in fact, successive use is the rule downstream to the Nebraska border.
c. New supplies of water can come from the West Slope only from
trans-basin diversions. Municipal water supply for new growth can
come either from this source or by condemnation or first use of agri-
cultural rights.
d. Stream quality in the Front Range is degraded from municipal,
industrial point source, and non-point source runoff from urban areas
and agriculture. Reuse schemes must be viewed in the context of both
instream water quality and quantity.
Section III identified three possible reuse schemes. A subset of
the recycling scheme would involve reuse of water by industry or for
urban irrigation (e.g. golf courses.) An evaluation of the environ-
mental merits of the four potential reuse schemes is given in the
list below. For comparison purposes all four schemes assume a doub-
ling of population and water use in the municipality. All comparisons
are from a base case of the present si-tuation with limited reuse.
1. No Reuse
o Increase in the environmental effects of West Slope diversions
and/or condemnation of South Platte rights.
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o AWT needed to meet standards or the total load of ammonia
and nutrients to the streams will increase,
o Flow downstream will be augmented.
o TDS concentrations downstream decreased; total load increased,
2. Agricultural Successive Use
o Increased effect of West Slope diversions and/or condemnation
of South Platte rights.
o Stream quality below outfall improved (TDS and nutrients de-
creased) during irrigation season.
o Ammonia nutrient benefits to agriculture.
o Smaller AWT plant may be required.
o Potential public health effects and soil damage
3. Water Exchange - "First Use" by municipalities
o No additional effect on West Slope streams or from irrigation
water rights condemnation.
o Stream flow between water supply diversion and wastewater
plants reduced.
o Nutrient benefits to agriculture.
o Offstream storage may be required.
o Higher TDS and lowered flow downstream.
o Potential public health effects and soil damage.
4. Increase by Recycling
o No Additional effect on West Slope Streams or from irrigation
water rights condemnation.
o Higher TDS in City drinking water
o Possible other contaminates in drinking water.
o AWT Plant for Reuse and Discharge Required.
o Higher TDS and Lowered Flow Downstream.
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It is apparent in this analysis that no one system has an
absolute advantage over another. Total costs have not been evalu-
ated for such alternatives. There will be environmental benefits
and impacts with any system.
System No. 1 has the advantage of providing more flow downstream
to the agricultural community. In such a system however, the owners
of the imported water would have to receive compensation from poten-
tial downstream users for added water. West Slope streams would suf-
fer the environmental impact of stream depletion.
System No. 2 has similar benefits and costs to system 1 except
that stream quality in the vicinity of the municipality and immediate
downstream would be somewhat improved.
System No. 3 has the advantage of no additional importation or
condemnation of water rights. Nutrients are diverted from the stream
in favor of farms. TDS values in the stream may increase however and
stream flows within the vicinity of the municipality may be depleted.
System No, 4 involves no new or condemned water, but adds TDS
and possibly other contaminates to the municipal drinking water.
Alternatives to this are more expensive advanced wastewater treatment.
Downstream flows are also depleted and TDS is increased.
Complications of real life situations can confuse this idealized
analysis. In many cases, the depletions, nutrient removals and TDS
increments changes are small in comparison to the total water quality
problem. Such systems may only marginally change water quality.
Exchanges can be complicated if some other higher use is made of
canal waters (e.g. Barr Lake — an irrigation storage reservoir con-
templated as a recreation area).
West Slope diversions are generally not made on an incremental
basis. Reuse schemes like 3 or 4 may be made in conjunction with
large, capital-intensive West Slope diversions (e.g. Foothills and
reuse projects of the Denver Water Board).
Protection of agricultural uses near the metropolitan area may
not necessarily be safeguarded by "first use contracts." The decision
to retain farmland in agricultural use near a metropolitan area is
basically economically constrained. If the price of farmland conver-
sion to urban uses is high enough or if costs of operation (taxes,
distance from marketing areas) of farms gets too high, farmland will
still be converted. Given the same amount of water available for agri-
cultural uses, new farms or expanded farms farther away from the metro-
politan area may compensate for farmland lost around the metropolitan
area.
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Advanced waste treatment to remove NH-3, chlorine, and phosphates
is not now practiced in the Denver metropolitan area to meet 1983
goals. A commitment to removal of these substances will be an ex-
pensive proposition. The value of any of the reuse schemes must be
related to the most cost effective method of achieving these results.
Although the State of Colorado has classified most Front Range streams
as B-2 (warm water fishing, secondary contact recreation), funding
has not heretofore been available for advanced waste treatment. Should
the State determine that future funds will be used to remove ammonia,
chlorine and possibly phosphate, reuse schemes could prove to be a
cost-effective method of attaining water quality goals, However, ade-
quacy of flows and stream habitat do limit the fishery potential in
many streams in the Denver region. With certain reuse schemes which
may improve water quality, stream flows may be further depleted. There-
fore, both water quality and quantity must be considered in determing
impacts of reuse on proposed stream uses.
Traffic
Impacts related todependence on the automobile such as low den-
sity or sprawl development, congestion and high noise levels in the
central business district (CBD) will continue to worsen as the region
grows. The situation of the commute-hour traffic overload on the
region's highway system will continue and in some areas such as the
CBD and suburbs near the CBD it will become worse. New highway con-
struction to alleviate existing traffic problems will compound the
situation by providing additional highway capacity which can accom-
modate more growth and its traffic. Further suburban growth would
absorb the new capacity in a relatively short period of time. The
Federal Urban Mass Transit Administration's denial of funds for a
regional transit system eliminates the possibility of a fixed rail
system for the present time. Any regional transit system proposed
by the Regional Transit District (RTD) to compete with the auto-
mobile will have to rely on RTD's fleet of buses.
Such things as carpooling and vanpooling will reduce the number
of cars on the road by increasing the average number of people being
carried in each vehicle. The Regional Transit District has a bus
system which provides a good alternative to travel by automobile
only. A fixed guideway type of facility has been studied in an al-
ternatives analysis and has been shown to be no more efficient in
attracting people from their autos than a comprehensive Regional
Transportation System comprised totally of buses.
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DIRECT ENVIRONMENTAL IMPACTS
Climate
Construction activities are generally restricted during Chinook
events which are temporary in nature and occur primarily in the
winter when little heavy construction is done, thus minimizing
effects upon construction. Wastewater treatment processes involving
spraying, such as trickling filters and irrigation of effluent may
produce local aerosols containing microorganisms and dissolved
solids. During Chinooks, these aerosols could be carried long
distances. Some damages to physical property suffered during high-
wind occurrences which would result in temporary, higher energy
and cost requirements as repairs are made. Blowing particulate
matter from spray operations and sludge disposal sites may impair
vision and impede transporation.
All land application methods, including percolation ponds, will
affect the local microclimate. Volatilization of water molecules
may lead to a local fog formation during certain periods and produce
a nuisance effect. Such an effect could take place at the proposed
sludge land application site for Metro Denver which is located
close to the proposed Adams County general aviation airport
(Reference 126) causing costly delays in terms of time and manpower.
Low-temperature conditions can limit biological processes and
thus curtail certain treatment processes such as aerobic digestion,
trickling filter systems, and mechanical aeration.
The Littlefield/Englewood, South Lakewood, South Adams,
Aurora, and Metro plants have the highest potentials for odor
problems on still days. The proposed satellite plant on Cherry
Creek may have odor problems if future residential development
occurs nearby.
Hydrology
The construction and operation of wastewater treatment plants
can have important impacts related to the drainage network in the
study area. Plant siting can affect the water supply for the reach
below it by defining the point of return flow for the municipal
water system. Since both irrigation and municipal water svstems use
the drainage network for most of their supply, the point of return
flow of domestic water can be critical. Plant construction and plant
operation and maintenance will affect the water quality in the
drainage networks as discussed previously in the discussion of water
quality. Better water quality may decrease the level of treatment
for municipal systems and may even affect the quality of crops
irrigated with the water.
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Siting of those projects to be undertaken within floodplains
requires special consideration. They must be designed so as not to
increase the potential for flood damage either upstream or downstream.
Since facility damage may result in direct release of untreated or
partially treated sewage, the facilities must also be capable of
withstanding the flood depths and velocities to be expected.
Several interceptors such as Sand Creek as well as the central
plant expansion of the Metropolitan Denver Sewage Disposal District
No. 1, the Lower South Platte, and Cherry Creek satellite plants,
will be sited in floodplains.
Interceptors that will be aligned through wetlands/marshes such
as the proposed Sand Creek interceptor may cause adverse effects.
The trench excavation 'and the pumping to keep it dry during con-
struction will lower the groundwater table and may temporarily dry
up the marsh. If gravel is used to backfill part of the trench,
it could act as a drain to lower the groundwater table permanently.
On the other hand, any leakage of sewage from the interceptor might
adversely affect the quality of the water in the marsh.
Geology
No significant direct alteration of land forms is anticipated
through implementation of any of the alternatives. No significant
direct impacts of geologic hazards or on unique and significant
geological formations or structures are anticipated for any alterna-
tive.
Soils
Soil-related direct environmental impacts result almost exclusive-
ly from construction activities. These impacts consist of water
erosion from construction sites and commensurate temporary surface
water quality degradation. Wind erosion of exposed soils results in
windborne dust and particulates. These effects are generally
temporary or of short duration. The local alternative would cause the
greatest amount of these type of impacts, the regional alternative
the least, with the no-action alternative causing impacts more
similar in magnitude to the local alternative. No alternative would
cause significant adverse impacts.
Biology
Direct Impacts of Local Alternative-—
The identified alternatives would not significantly reduce flora
or fauna in the Denver metropolitan area. In general, the treatment
plant sites and the interceptor corridors do not support native
plant commities. Rather, each of the sites proposed for wastewater
treatment facilites is usually typified by introduced vegetation and
wildlife species tolerant of human presence. All of the facilities
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are situated either in urban areas or areas traditionally supporting
agriculture and grazing activities. Three types of potential
impacts upon biotic communities have been identified. The first
two relate to construction activities while the last one concerns
facilities operations.
Disturbance or Loss of Vegetation and Wildlife Habitats—New
treatment plant facilities and interceptors would be constructed
for the following service areas: South Adams, Englewood/Littleton,
Cherry Creek/Goldsmith Gulch, Lower South Platte, Clear Creek/Sand
Creek, and Broomfield/Westminister. Site construction would entail
the removal of ground cover and reduction of habitat for some small
animals. Principal plant cover in adjacent areas would remain rela-
tively unaffected. No losses would be anticipated for highly pro-
ductive habitat or rare and endangered plant or animal species. The
main differentiation regarding impacts on vegetation and wildlife
which can be made between the various facilities plans is related to
the size of the facilities and subsequently the amount of flora and
fauna that would be removed.
Disturbance of Aquatic Habitat during Construction—Treatment
plant construction adjacent to watercourses could cause short-term
disturbances to the aquatic environment. Facility sites with potential
effects on aquatic systems are Big Dry Creek, Lower South Platte,
and Clear Creek and Englewood/Littleton. Other facilities will prob-
ably use existing outfalls or convey effluents to a regional facility.
Removal of riparian vegetation could increase erosion and adversely
affect water quality and aquatic habitat. Increased turbidity and
sedimentation will -disrupt bottom habitat, kill invertebrates and
degrade water quality. These effects on the aquatic environment would
be a short-term adverse impact for up to several thousand feet
downstream of the facility. Physical stream conditions would be
restored by the natural scouring and restoration effects of spring
flows or seasonal upstream releases.
Effects upon Aquatic Environment during Facilities Operations—
All of the proposed facilities would improve local water quality
within the Denver area. The South Platte River would benefit from
higher quality effluent discharged by the Englewood/Littleton, South
Adams and Metro Central Plant facilities. Big Dry Creek would receive
surplus flows from the Broomfield/Westminster facility.
This improvement in water quality would enhance productivity of
the aquatic environment and, through the food chain, would also
enhance productivity of the terrestrial environment. The resulting
greater carrying capacity of these ecosystems could likely increase
the number of individuals supported in the area. The potential for
establishing species not presently supported in these reaches of
San Creek, Clear Creek, Big Dry Creek and the South Platte River is
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likely to have both beneficial and detrimental ramifications. Over-
all, the multiple discharges provided in the local alternative offer
the opportunity to increase habitat areas and promote a diversity of
plant and animal species in the aquatic environment.
Direct Impacts of Regional Alternative—
The regional alternative, in general, would have fewer direct
impacts than the local alternative due to the limited number of
facilities. Potential impacts can be divided into the terrestrial
environment of the facilities sites and the aquatic environment
affected by the treatment facilities.
Disturbance or Loss of Vegetation and Wildlife Habitats—Construe*
tion of new facilities will be limited to the Englewood/Littleton and
Metro (MDSDD #1) treatment plant sites. Interceptor routes that will
be constructed through vegetated areas include portions of the Lower
South Platte drainage course. Other interceptor routes will follow
established roadways. Impacts of biotic communities would be
similar to those discussed under the local alternative.
Effects upon Aquatic Environment—The regional alternative con-
solidates all wastewater flows, except Englewood/Littleton and West-
minster/Bloomfield, to the Denver Northside and Metro Central plants.
With the abandonment of local treatment plants, stream areas will
benefit from the termination of local discharges high in BOD, sus-
pended solids, ammonia-nitrogen, chlorine and other pollutants. On
the other hand, diversion of effluent discharges would reduce
local stream flows by 2-10 mgd. This would have a noticeable effect
on smaller watercourses such as Sand Creek and Big Dry Creek where
diminished flow reduces the amount of aquatic habitat. In compari-
son with the local alternative, the greatest number of discharges
(including reuse) would have the greatest benefit to the natural
environment through enhancement of the water regime.
Direct Impacts of the No-Action Alternative—
The no-action alternative embodies the same facilities as the
local alternative. Impacts relating to the disturbance or loss of
vegetation and wildlife habitats and the disturbance of aquatic
habitats during construction are similar to those discussed in the
local alternative section. The main impacts of this alternative are
the effects caused by delays in project implementation.
Effects upon Aquatic Environment—One to three year delays in
project implementation will require the continued use of local treat-
ment plants and discharges to local streams, but eventually the
beneficial impacts will approach but not equal those expected under
the local alternative. The perpetuation of water quality problems
presently experienced in some stream segments will be a short-term
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impact lasting an additional one to five years. Ammonia-nitrogen and
chlorine residual, which in excess concentrations are toxic to
aquatic life, are the parameters of significant concern to the South
Platte River from the South Adams and Englewood/Littleton facilities
and to Sand Creek near the Aurora facility.
Energy
Estimates of the energy consumed in the construction of facilities
described for each alternative are not available. However, a limited
comparison between alternatives is possible. Three factors can be
considered. These are the total length of installed interceptors, the
number of plant expansions and/or upgradings in treatment levels, and
the number of new plants constructed under each of the three alterna-
tives during the next five years. Assuming one unit of energy per
mile of interceptor, one unit per mgd of plant expansion, and one-and-
one half units per mgd of new plant capacity; a comparison of con-
struction energy demands indicates that the local and regional alter-
natives are essentially the same. The no-action alternative con-
struction energy demand would be about 20 percent less for the five-
year period. As the no-action alternative includes delays in con-
struction beyond the five-year period considered in this comparison,
not all the reduction in energy demand would be realized.
Energy use during operation of the facilities will be dominated
by the wastewater treatment plants themselves. First order estimates
of the increase in natural gas and electrical power yearly demands
of the alternatives five years hence are:
Local Regional No-Action
Natural gas, million cubic feet 40 30 8
Electric power, million kilowatt-hrs 11 9 3
In this instance, the local alternative will result in the highest
increase in energy demand. The significant qualities of natural gas
demand for the local and regional alternatives are of particular con-
cern as shortfalls in natural gas supplies for the Denver region
are expected for the 1978-79 heating season. As wastewater treat-
ment plants should be considered as interruptable consumers of natural
gas, loss of process heat is a real possibility. Plant effective-
ness would be degraded with consequent deterioration of effluent
quality during stream low-flow periods. Stream or receiving waters'
water quality could therefore be significantly affected.
Transportation
Direct impacts are construction-related and thus of a temporary
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nature. These impacts relate to disruptions of traffic flow near
construction sites, and are likely to be greatest for the local
alternative, somewhat less for the no-action alternative, and least
for the regional alternative. No significant adverse impacts are
anticipated.
Historical and Archaeological Features
Although no individual wastewater treatment plant would cause the
removal or destruction of a designated historical landmark, some of
the sites are near designated landmarks or in historical areas. The
South Platte River valley, downtown Denver and Cherry Creek vicinity
are areas of great historical interest; new interceptor lines will
pass through these areas and the other creek basins as well in the
regional alternative. Although historic sites having potential for
official recognition as well as currently designated ones are not
directly threatened by construction activities, they could be damaged
structurally by such construction techniques as blasting and trench-
ing. Hauling off construction material past historically significant
points during the construction phase of one to two years duration
could cause accumulative vibrational effects, but only in a very
localized corridor along construction routes. Vibrational effects
of hauling are of much smaller effect than actual pipeline excavation.
Depending on the depth to bedrock or impervious layer and other factors,
carving or blasting may be required along limited segments of the
interceptor routes. Facility planning in the current planning stage
has not determined the exact alignments. As excavation impacts are
generally localized within approximately ten feet on each side of
the trench, it would not be appropriate, and perhaps misleading, to
project impacts over large areas until such information becomes avail-
able. The effects of dust and dirt raised by construction activities
upon historic sites would also be minimal and difficult to predict
at this time.
Archaeological information is not avialable in published form.
Site reports have been obtained from the Colorado State Archaeologist
and are in the process of being mapped for inclusion in the final EIS.
Outdoor Recreation Sites
Very few current recreation sites will be directly affected by
construction of the proposed wastewater treatment facilities under
any alternative as few new plants are planned. More new facilities
are incorporated in the local alternative than in the regional alterna-
tive, thus potential impacts of the local alternative are greater.
Water-based recreation plays a major role in Denver. Many recreation
sites are located adjacent to or surround streams, lakes and reservoirs.
As wastewater treatment facilities are to be located at points along
these streams and several interceptor routes have been planned to
lie adjacent to stream beds, some conflicts in siting may arise. The
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Bureau of Outdoor Recreation (BOR) has identified some possible
areas of conflict along Sand Creek, Clear Creek and the Lower South
Platte drainages and has recommended that multiple use of land be a
planning goal. A recreation plan is being developed for the Sand
Creek-Tollgate stream corridor as a segment of the Corps of Engi-
neers' Denver Metro Study. The proposed interceptor right of way
would be a good location for hiker-biker trails to connect with
those of the South Platte River Greenway. The proposed Clear Creek
treatment plant location could be a potential recreation site. Either
alternative could incorporate a trail system similar to that of Sand
Creek. For the Lower South Platte, the BOR has identified in the
Denver Metro Study (Reference 126) that a new wastewater treatment
plant at 164th Avenue may conflict with a potential recreation site.
Stream flow will be augmented through treated discharge at many
points in the local, new plants alternative, rather than at a few
plants in the regional and no-action alternatives. The BOR has
identified four areas of recreational benefit and potential resulting
from new plant operation:
1. Return of a steady water flow to the Sand Creek, which
could increase recreation benefits for hiking, bicycling
and nature study. This would not occur under any of the
current alternatives.
2. Return of water flow to the proposed Corps of Engineers re-
servoir to help maintain a conservation pool.
3. The use of additional open space acreage for certain kinds
of recreation around the plant site.
4. Construction of certain components of the plant underground
and utilization of the surface area for park and recreation
purposes.
In addition, discharges of water of a relatively higher quality
than the current stream flow will enhance fishery potential in areas
not radically modified by channel improvements (see Map F), if the
flows are high enough to sustain a fishery and if water quality is
also sufficient to support a fishery. Increased flows will also
enhance other recreational activities such as boating, contact re-
creation if health-related water quality standards permit, and gen-
eral stream aesthetics, thus serving to enhance the quality of re-
creational experience obtainable at downstream sites. The more
specific impacts on water quality and flow augmentation are addressed
in the Water Quality section.
Two factors considered in the biological direct impact section
have effects upon outdoor recreation: (1) the disturbance or loss
of vegetation and wildlife habitats; and (2) the disturbance of the
aquatic environment. In the local and no-action alternatives, seven
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new treatment plant sites and two new interceptor routes will perman-
ently remove ground cover and reduce small animal habitats. This
will reduce potential recreational opportunities in these areas.
Although water quality will be enhanced by the addition of high-
quality effluent, during the construction process disturbances such
as erosion of banks and siltation of streams may extend up to several
thousand feet downstream and last one to two years, thus impairing
downstream recreational experiences. Those alternatives with the
greatest number of discharges including reuse would have the greatest
benefit to the natural environment and recreational experiences
through enhancement of the water regime.
Land Waste Treatment
None of the proposed alternatives contemplate land percolation
or infiltration as a wastewater treatment method. However significant
reuse is planned where effluent would be used for urban or agricultural
irrigation either directly or through exchange agreements. See
Appendix A for details of future plans. Another motive for reuse,
particularly through exchange agreements, is to secure additional
water supplies for domestic or industrial use. Irrigation reuse is
also attractive as discharges to streams are reduced with usually
beneficial effects on stream water quality.
Crop irrigation with wastewater effluent, of the quality
expected from proposed facilities, is generally restricted in
the United States although more common in Europe. Use for ir-
rigation of crops for direct human consumption is generally
prohibited. The reasons are based on unknown risks of contam-
ination by pathogens (bacteria and virus), mutagens, and carcino-
gens. Other concerns are buildup of salts in soils reducing pro-
ductivity, buildup of heavy metals and chlorinated hydro-carbons
in^soils and subsequent uptake by plants, and eventual contamin-
ation of ground waters. Thus, unrestricted reuse for agricultur-
al irrigation is not feasible without accepting the risks and
impacts of such practices.
Aesthetics
Direct impacts on the visual and aesthetic environment can be
divided into construction effects lasting only a short term and
operation effects which entail both short- and long-term impacts.
Similar types of effects occur within the local, regional and no-
action alternatives. Differentiation between alternatives basically
relates to the amount of area disturbed by the individual facility
sites.
Construction Effects—
Adverse effects on local aesthetics during construction are
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generally related to nuisance factors. Pipeline excavation and
treatment plant site preparation entail earth-moving, grading and,
in some cases, dewatering. Depending upon seasonal and topographic
conditions, the generation of suspended particulate matter is un-
avoidable. Construction noise, engine emissions from heavy equip-
ment and vibrations are other nuisance effects. Traffic rerouting,
temporary stockpiling of materials along roads, and increased truck
traffic during construction period constitute temporary inconven-
iences which will require residents to make short-term adjustments.
Operation Effects—
The local alternative with multiple treatment facilities would
tend to have a greater odor, noise and visual impact than the region-
al alternative. The construction and operation of a treatment plant
would certainly be intrusive and would tend to alter the character
of the surrounding area. The structural facilities can be located
away from areas of high visibility and designed to be visually and
aesthetically compatible with the environs. However, plant opera-
tions will entail equipment noise, processing odors, incidental
lighting and traffic from maintenance vehicles to some degree. Facil-
ity sites creating the greatest disturbance would be those closest
to residential or commercial developments. Thus, expansion of the
Aurora plant, the proposed Clear Creek plant, and the South Lakewood
plant may cause some conflicts.
Facility plans which incorporate some system of treatment or
disposal by land application would be more land-intensive than
structural treatment systems. Land application probably would not be
noticeable as a distinct and separate land use within an agricultural
community. However, potential odor problems during adverse conditions
may affect a larger area than that of a small physical plant.
In an overall evaluation, the improvement of wastewater treat-
ment in the planning area strives toward obtaining and enriching
cultural goals such as recreation, ecological viability and aesthetic
enjoyment. These are presently fulfilled in the mountain parks and
streams west of Denver. For the plains streams, however, improvement
in water quality alone will not fulfill those goals. Hendricks and
Bluestein (Reference 982), in their study of the South Platte River,
concluded that:
"Their achievement is essentially precluded by the
modifications brought about by intense human uses of
the stream and associated lands and by the natural
characteristics of the plains streams. Thus, improve-
ment of water quality in the plains South Platte to 1983
levels (as specified by PL 92-500) will result in few
benefits and at very high costs. However, to permit
deterioration of the mountainous South Platte will re-
sult in irrevocable societal losses. From all of
IV-95
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this, it would seem that the most cost
effective investment policy would be to protect
the mountainous South Platte from deterioration
and to maintain the plains South Platte to
permit continuance of exisitng human activities."
IV-96
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V. Mitigation
of Impacts
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SECTION V
MITIGATION MEASURES
The significant adverse impacts identified and assessed in Section
IV are further examined in this section to determine the means by
which they may feasibly be avoided, eliminated or minimized, This
examination is divided into six categories of major interest: growth
impacts, air quality, water quality, energy, growth-induced impacts
and direct impacts.
A number of the mitigation measures evaluated in this section
will address regional land-use impacts over which EPA has little di-
rect authority. No attempt has been made to limit evaluations of miti-
gations to only those which EPA has the authority to implement. This
approach has been taken because of the nature of regional water quality
and related problems, which have been created in a framework of over-
lapping jurisdictions and which must be solved to a great extent with-
in that framework. It is necessary for EPA and other concerned par-
ties to understand to what extent water quality and other environ-
mental problems may be solved through EPA's direct efforts and to what
extent it must rely on other governmental bodies. The results of this
approach have raised or amplified issues regarding the adequacy of
existing air quality, water quality and land-use regulations operating
in the Denver region. This section is intended to stimulate discus-
sion and debate by decision-making bodies, responsible agencies and
the general public on desirable ways to remedy the impacts assessed
in this EIS.
MITIGATION MEASURES FOR SOCIO-ECONOMIC IMPACTS
Socio-economic impacts rarely lend themselves to straightforward
mitigation. Due to their complex causes and consequences, simple,
short-term remedies cannot always be prescribed. Generally, less di-
rect and more costly long-term program solutions are recommended. The
overall effectiveness of mitigating programs is too variable to pre-
dict because of various limitations such as inadequate enabling au-
thority, staffing and budgets which are too often placed on individual
programs. Yet, even with adequate authority, staffing and budgets,
there can be no guarantee that a given program will be effective. Some
socio-economic problems simply cannot be solved by funding new programs
or reorganizing existing ones. Thus, the implementation of the miti-
gating programs mentioned below may or may not be reasonably success-
ful in avoiding, eliminating or minimizing the socio-economic impacts
assessed in Section IV. These mitigations will require further con-
sideration and study by the Denver region's governmental agencies and
by the general public before any concensus can be reached as to their
appropriateness and desirability.
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The following discussions on various types of mitigations pre-
sent a number of steps that could be taken to improve the effective-
ness of planning in the Denver region. Those listed below arose
frequently in discussions with local planning officials but are by
no means an exhaustive inventory.
Reduce the Number of Special Districts
The proliferation of special districts has created numerous
problems in coordinating capital facility planning and in assuring
reasonably similar levels of cost for similar levels of service
throughout the region. Some of the suggestions made were for the
formation of a regional services agency (Reference 1044); another
was that the municipal government should assume all special service
functions (Reference 1045).
Establish a Formal Environmental Review Procedure
This might take the form of a state or regional environmental
review agency, as suggested by Adams County Planning Director Robert
Fleming (Reference 1046), or it could be modeled on the environmen-
tal protection legislation of other states. Such "mini-NEPA" laws
open decision-making on private and public project proposals to
public review before discretionary action by local government and
thereby permit citizen review of and comment on private development
proposals. Environmental review procedures under the National En-
vironmental Policy Act of 1969 (NEPA) apply only to federal actions
and actions involving federal interests.
Establish Regional Land Use Planning for Major Uses
and Natural Resources
The development of major types of land uses (such as large in-
dustrial establishments) could be made subject to review and approval
by a regional agency which could take into consideration the loca-
tional requirements of major uses and the broad environmental con-
cerns of the region as a whole in a manner local agencies cannot. Em-
powering such an agency to review major industrial and transportation
related development decisions could help the region move toward
greater integration in planning for all kinds of uses. Such an agency
might be able to protect agricultural uses and environmentally sen-
sitive areas more successfully than local governments can.
Move Toward a System of Regional Tax-Base Sharing
Reducing the fiscal rivalry which distorts both community land
use patterns and industrial location decisions could be accomplished
under a program of regional tax sharing. Such a system, like that
developed for Minneapolis/St. Paul, might begin by sharing only the
increase to assessed valuation arising from new development; this
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initial step would be more acceptable than an across-the-board tax
sharing plan, which would wipe out the fiscal advantages many com-
munities have assiduously striven for through years of planning.
However, even the sharing of the assessed value increment would
go far to reduce rivalry for tax base and permit other kinds of
development criteria, including environmental criteria, to carry
more weight.
Establish a Fiscal Cost/Revenue Balance as a Condition of
Development Approval
The citizens and officials of a community often make decisions
on development proposals without knowing if the revenues generated
by the development are in balance with the costs required to provide
municipal services. When costs are significantly and consistently
out of balance, inefficient development patterns usually result. The
establishment of policies will require the development of methods
of determining fiscal costs and revenues to a municipality. The
DRCOG could provide assistance in developing such policies and methods
which must recognize that other economic and social considerations
may override the goal of balanced costs and revenues.
Accelerate Development of Parks and Recreation Sites
The forecasted decrease in the per capita recreation area within
the region and the associated adverse impacts can be mitigated if
local agencies developed and implemented plans to acquire and develop
recreational and park sites in the Denver region. The aggregate a-
mount of land that needs to be developed is about 400 acres a year
for the next several years to maintain existing park density.
Discourage Growth in the North and Northeastern Portions of the
Denver Region
About 75 percent of the agricultural land, including 85 percent
of prime agricultural land, forecast to be lost to urbanization by the
year 2000 is located in Adams, Arapahoe, and Boulder counties. Over
half the prime agricultural land expected to be lost is located in
Adams county. By not providing grant funds for capacity expansions
of wastewater treatment facilities in Adams County and the plains
portion of Boulder county, growth may be slowed in these areas and
redirected to other areas of the Denver region. Growth is supported
by other urban services, as well as by wastewater collection and
treatment. Therefore, the effectiveness of this mitigating measure
will be limited unless supported by coordinated federal, state, and
local government policies.
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MITIGATION MEASURES FOR AIR QUALITY
As described in greater detail in the Probable Impacts Section
and reference 998, National and State air quality standards will
continue to be violated in Denver over at least the next decade and
probably the next 25 years. This result includes the probable emis-
sion reductions attributable to the Federal program for control of
vehcile emissions as well as existing industrial stationary source
controls and State particulate control regulations. Predictions
indicate that carbon monoxide (CO) concentrations will exceed the
8-hour standard in some portions of the Denver region through 1985,
and "hot spot" concentrations will probably continue to exceed
standards through the year 2000. Ozone (03) concentrations will
continue to violate the National standard in 1985, and by 2000 will
be reduced to concentrations nearer but exceeding the standard
(.08 ppm) for the assumed meteorological conditions. Nitrogen Di-
oxide (N02), which is not presently recorded to be in violation of
the annual standard, is expected to decrease in concentration in
line with the expected reductions in ozone. Particulates which
presently greatly exceed the air quality standards are predicted
to get worse through the year 2000.
As previously indicated, these air quality predictions assume
certain emission controls, which presently exist and are administered
by the State of Colorado for industrial type sources and certain par-
ticulate sources along with projected vehicle emission controls, but
do not include all technically feasible control measures. In addi-
tion, these results assume and are based on the regionally adopted
year 2000 transit, highway and land use plans. Of concern to EPA
in mitigating these air quality impacts, is what strategies and/or
plan changes may be most effective in reducing pollution in Denver,
both in the near term and over the next several decades. Once iden-
tified, the question becomes how might the implementation of these
mitigating strategies or plan alterations be encouraged by EPA's de-
cisions on the funding wastewater treatment and conveyance facilities
and on the recommendations of the Clean Water Program (Denver 208 plan)
The following discussions explain the implications of certain
changes in the stated assumptions which were used to predict the
probable air quality impacts. The results of these changes on air
quality forecasts can be used to make certain inferences about the
mitigation potential of future land use, population, vehicle usage,
and emission control decisions. Therefore, the investigation of the
assumptions made regarding land use, transportation, etc., provides
information on the sensitivity of the air quality modeling results
to these assumptions, and the potential for changes in regional de-
velopment and transportation plans and implementation of pollution
control strategies to improve Denver's air quality.
V-4
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Mitigation of Growth-Related Air Pollution Emissions Through Land
Use Control of Development Patterns
To aid EPA's decisions on requests to fund construction of ad-
ditional capacity in wastewater facilities, it is important to know
not only the consistency of regional development plans with air
quality goals, but also the potential for reducing air pollution
through future land use modifications. Therefore, an analysis was
undertaken to ascertain the potential for changes in pollutant con-
centration and distribution which could be expected if the population
growth patterns in the Denver Metropolitan area were to be changed.
Outlying areas which were considered to be subject to relative-
ly high growth rates were divided into six areas, each with com-
parably equal projected population growth. These areas were named:
1) Broomfield/Westminster/Arvada; 2) Northglenn/Thornton; 3) Aurora:
4) South Metro; 5) Urban Jefferson County and 6) Lakewood. To simu-
late the air quality impact of a redistribution of population in
different parts of the Denver region, several computer runs were
made in each of which the year 2000 emission rates, in one selected
area, was reduced by 25 percent, with this deficit in emissions re-
distributed to all other areas in proportion to their populations.
Also a computer run was made in which the emissions within the Denver
city limits were reduced by 17 percent and likewise redistributed
to other growth areas. These perturbations were intended to repre-
sent larger, more isolated changes than might likely occur in the
normal course of events, but at the same time recognize the exist-
ing urban form in Denver. This analysis was performed for each
regulated pollutant. Air quality model runs for ozone were also
used to determine the sensitivity of short-term carbon monoxide or
nitrogen dioxide concentrations to this redistribution of emissions.
Particulates and N02 annual averages were computed separately.
In spite of these changes in emission patterns, almost no de-
tectable change in ozone concentration or distribution was computed.
Differences between all simulations for ozone were confined at all
times of day to at most 1 part per hundred million in one or two
grid squares. This result is attributed to the time required for
ozone production. By the time significant amounts of ozone has
been formed, the emissions are too well mixed to reflect their ori-
gins. Since the formation of N02 from NO emissions follows essen-
tially the same process as ozone. Short term N02 results were ef-
fected very little. It is reasonable to expect that very little
difference in the annual average concentrations of this pollutant
would result from a similar redistribution of NO emissions. Although
a similar analysis was performed for CO, it is reasonable (due to
the rather localized nature of CO pollution) to expect that CO "hot
spot" concentrations would not be revealed. Critical intersections
V-5
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or parking lots would not necessarily change with growth of
the community.
In the same manner as for ozone predictions, the sensitivity
of annual average particulate concentrations to a redistribution
in emissions was determined. The results showed that a 25% re-
duction in particulate emissions did not result in a 25% reduction
in concentrations, but rather a 5 to 10% reduction in the vicinity
of the reduced emissions. For non-reactive pollutants such as CO
and particulates, ambient local concentrations are made up from
both regional and local emissions, Therefore, a reduction in
emissions locally will not result in an equal reduction in concen-
tration due to the influence in regional pollutant emissions.
The results of this analysis indicate that region-wide control
of pollutant concentrations is -not achieved by a substantial re-
distribution of emissions. For particulates and probably CO, emis-
sion redistribution results in local reductions in concentration
equal to some fraction of the local emission reduction. Thus, it
would not appear to be fruitful to utilize, restrictive, local land
use controls, which might promote development elsewhere, in order
to relieve regional air pollution problems. Rather, it appears
that for ozone an overall reduction in emissions is needed and for
carbon monoxide a composite emissions reduction in many local "hot
spot" locations (i.e., major arterials, freeways, and intersections)
should be pursued in land use and transportation planning.
It should be noted that the above discussion is based solely upon
a redistribution of emissions not a reduction within the region.
Changes in land use patterns towards much higher density may reduce
total emissions through increased use of transportation modes other
than the automobile and by producing more energy efficient living
systems. However, without significant reductions in vehicle emis-
sions or reduced use of the automobile, the exposure to high pollu-
tion levels, within these high density areas, could be even greater
than presently forecasted.
Mitigation Through a Region-wide Reduction in Emissions
It is conceivable that with real changes in the expected future
land use, population growth and the proposed transportation system
for the Denver region, that an overall change in pollutant emissions
will occur. This would result in a different picture of the future
air quality than that described in the Probable Impacts Section.
More people and greater use of the automobile than presently projected
will result in worse air quality than previously described. However,
this possibility is not discussed here since mitigation of the pre-
sent and projected pollution problem is EPA's objective, Intuitive-
ly, a reduction in air pollution will occur if people drive less,
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and if less petroleum based fuels are used by stationary sources
than now projected for the year 2000. However, it is not known
to what extent decisions on the Federal, State, regional or local
level might affect this new trend and secondly, what the exact
effect would then be on the region's air quality. By making dif-
ferent assumptions about future population growth and transporta-
tion systems, and then determining the change in emissions, the
change in air quality could be determined through modeling to
answer the second question. Such an evaluation has not been per-
formed. However, if a uniform reduction in emissions is assumed,
from that presently projected, the resultant ambient air quality
change can be determined. This type of simulation was performed
to determine the effect of a uniform 30% reduction in emissions,
on ozone formation. Such a reduction, regionwide is considered
to be very significant, if attainable, and requires the implemen-
tation of all mitigatiye strategies such as parking controls and
exclusive bus and car pool lanes, gasoline rationing, etc., to re-
duce vehicle miles of travel. It was found that a 30% uniform re-
duction in 1976 emissions resulted in approximately a 15% reduc-
tion in peak ozone concentrations in the region. Such a reduction
in ozone concentrations would not result in immediate attainment of
the ambient air quality standard. However, the ozone standard might
be attained in about 20 years.
Probable Effects of an Automobile Inspection and Maintenance Program
A motor vehicle inspection and maintenance program will not elimi-
nate the pollution problem in the Denver area, but it is a necessary
first step in attacking one of its major sources. If passed, the
proposed legislation will require, beginning January 1, 1979, the
annual inspection and necessary maintenance of 1977 and later model
year motor vehicles to help insure that their air pollution control
systems work as designed. It is proposed that the inspection and
maintenance program would work in much the same way as Colorado's
safety inspection program. It is estimated that an inspection will
cost around $5.20. When needed, maintenance may cost from twenty-
five to fifty dollars. The program will not only reduce air pollu-
tion but will also result in gasoline savings through more efficient
engine performance.
The exact impact on air quality of the proposed inspection and
maintenance program has not been determined. In the Probable Im-
pacts Section, the air quality impacts are discussed assuming the
inspection and maintenance program is not put into effect, which is
the present situation. In contrast to the air quality predictions
given in the Probable Impacts Section, estimates of the air quality
in Denver have been made assuming very strict compliance of automo-
biles with the Federally mandated auto emission limitations. In
fact, strict compliance is not being achieved today and is not pro-
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jected to even nearly being achieved in the future without some
kind of inspection and maintenance program. This is due to the
fact that: 1) manufacturers are presently not able to produce
cars which meet all of the emission limitations; 2) a certain
percentage of cars experience early failure of the catalytic con-
verter (the principal emissions control device) and; 3) many auto-
mobiles are not properly maintained to meet the emission limita-
tions and others are maladjusted. An inspection and maintenance
program will greatly reduce the latter two problems in meeting
the Federal emission standards.
Although not exactly the result of implementing an inspection
and maintenance program, strict compliance with Federal emission
standards would reduce carbon monoxide concentrations by almost
40 percent of that projected for 1985 in the Probable Impacts Sec-
tion. Regionally, although not in all "hot spot" locations, ad-
herence to auto emission standards would bring CO concentrations
very close to the 8-hour ambient standard in 1985. For ozone the
effects of properly controlled automobile hydrocarbon emissions
would not be as great as for CO. Peak ozone concentrations would
be reduced for 15 pphm to 13 pphm in 1985, a 13 percent reduction;
and from 11 pphm to 9 pphm in 2000, an 8% reduction.
Possible Effects of a Relaxation of the NO Emission Standard
In a different assessment of the probable effects of changes in
vehicle emissions, the impact on ozone and N02 concentrations of
an increase in NO emissions (as presently proposed by the automobile
manufacturers) was evaluated. This air quality simulation assumed
a relaxation of the NOX emission standard roughly corresponding to
a proposal now before Congress to permit 1 gram/mile NOX emissions
rather than the 1978 goal of 0.4 grams, mile. Results of this simula-
tion for conditions otherwise the same as the 1985 probable impact
results showed only slight violations of ambient standards for ozone
and no increase in peak N02 concentration. With strict compliance
with Federal vehicle emission standards, as discussed above, except
for the proposed relaxation in the NOX standard, no violation of
the ozone ambient standards was predicted for 1985.
The reason for an improvement in air quality with increased NO
emissions is that the ratio of the two ozone precursors, hydrocar-
bon and NO become unbalanced. Not enough hydrocarbon would be pre-
sent to oxidize the NO to N02 to in turn produce ozone before atmo-
spheric mixing and dilution lowered all concentrations, This re-
sult is specific to Denver's bad ozone days (3 August and 28 July
1976). Regions with other emission mixes or patterns and other dis-
persion climatology would probably experience different results.
Specifically areas with more persistent inversion conditions will
probably have a worse ozone and N02 problem if the NO emissions
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standard is relaxed. Therefore, as a National strategy the impact
of relaxation of the NO standard has not been determined.
It should be noted that if the NO standard is relaxed this
results in a larger NO plume coming from Denver. Any downwind area
releasing hydrocarbons into this plume will experience large ozone
concentrations because of the reaction with the N02 originating from
Denver's NO emissions, Also? the predicted decrease in ozone con-
centrations in the Denver region would, of course, be accompanied
by increases in NO concentrations. Although there is no Federal
air quality standard for NO, (only an N02 standard), it is not prob-
able that increased NO concentrations are desirable. NO does oxi-
dize to N02 and N0£ is regulated pollutant. Increased NO emissions
do not necessarily lead to increased N02 concentrations in the Denver
region for reasons similar to those explaining the ozone reduction.
Increased downwind N02 concentrations could, however, be expected,
because of the longer time available for the conversion of NO to
N02. Thus, any proposal for relaxation of the NO emission standard
as a pollution control measure must be done after a national account
of potential downwind effects, for both ozone and N02, and the know-
ledge of the health effects of higher NO concentrations.
Control of Particulates from Street Sanding
According to the 1974 Denver Emissions Inventory street sanding
and the resultant dust generation from automobile traffic is the
major source of particulates in the Denver region. Also, street sand-
ing and use of salts is a significant non-point source of water pollu-
tion in the region. Therefore, a program to mitigate the impact of
this source of particulate air pollution will also have water quality
benefits and vice versa.
Most controls for dust generated from paved streets are concerned
with reducing the amount of material on the street surface. In a re-
cent report which considered results from several studies carried out
in cities other than Denver, three different methods of street clean-
ing were evaluated. (See reference 129), These were mechanical
broom sweepers, vacuum sweepers, and flushers. None of these con-
ventional street cleaning methods were found to be effective in all
areas studied. Rather, the results are mixed. In some cases signi-
ficant reductions in particulate concentrations were found, in others
there was no measurable change. The relationship between cleaning
and emissions is complex in that emission rates are not directly re-
lated to the loadings removed from the street nor closely related
to the street surface loadings.
Street flushing, one of the methods examined, reduced particu-
late concentrations in certain studies,_ Apparently, flushing has
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an effect similar to rainfall, with a substantial reduction in par-
ticulate concentrations in the air on the day of flushing, but
little effect on following days. A reduction of 16 yg/m^ on the
days of flushing is an estimate of the impact of this street clean-
ing method in high traffic density areas, Flushing, however, does
not remove material from streets but moves it from traffic lanes
to the curb. With subsequent rains or snowmelt, the suspended
solids loadings in storm water runoff would not be reduced. In
fact, short-term concentrations might be increased since the mate-
rial is already concentrated in the gutters. Theoretically, a com-
bination of flushing followed by a pickup of material in the gutter,
with either broom sweepers or vacuums would provide optimum clean-
ing for both the air and water pollution control. However, in two
studies where a combination of flushing and sweeping was performed,
no significant reductions in particulate concentrations were observed.
In one study, broom sweeping was found to reduce average parti-
culate concentrations but appeared to be ineffective in two others.
This method of reducing street generated dust has limitations in
that it moves material from the gutter back into the street and is
not efficient in removing fine particles. As an optimum a 6 to 20
yg/m-^ reduction in average particulate concentrations in air might
be achieved with a broom sweeper.
In the studies which evaluated vacuum cleaners they found no
reductions in particulate concentrations, Dust may have actually
been suspended in the air by escaping from the top of the vacuum
sweeper. In one study, the insiginficant contribution of street
sanding to the ambient particulate concentration may have negated
any positive effect.
Because of these limited and mixed results, definite conclusions
cannot be drawn as to the effectiveness of street cleaning as a con-
trol strategy for participates. Demonstration studies in the Denver
area would provide the best mechanism to determine the potential
effectiveness of this street cleaning strategy in improving both
air and water quality.
Although the relationship of street sanding to particulate con-
centrations is complex, it appears ambient concentrations are direct-
ly related to traffic volumes. Therefore, reductions in traffic
volumes may present the most effective method of reducing the par-
ticulate air quality problem. Beyond controls which reduce automo-
tive tail pipe emissions, reductions in vehicle use and miles travel-
led also appear to be the most effective measure for controlling
carbon monoxide and ozone pollution. Therefore, Denver's air qua-
lity problem for all pollutants which are in violation of the Na-
tional Ambient Air Quality Standards is and will continue to be highly
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related to the degree of dependence upon the automobile for trans-
portation.
Implementation of Air Quality Mitigation Measures
As discussed earlier the reason for evaluating the probable air
quality impacts and potential mitigation measures in this Environ-
mental Impact Statement is to establish the most consistent approach
practicable to meeting both air and water quality goals within the
Denver region. The common element between these two environmental
concerns is the effect of population growth and development within
the region on air and water quality, given the feasible and imple-
mentable technologies for controlling these forms of pollution
separately.
It appears that even with the emission reductions expected from
the Federal emissions control program and with implementation of the
inspection and maintenance program that air quality standards will
continue to be violated through 1985 for ozone and CO and possibly
until 2000. The particulate problem will persist with little re-
lief in sight. By 2000, the ozone and CO problem will be reduced
to within a range which will be very close to the standard, but vio-
lations may still be recorded. However, the effect of the vehicle
emissions control program is expected to reach its peak reduction
potential by around 1995. Therefore, any subsequent growth in traf-
fic will cause the deterioration of Denver's air quality.
In considering options for promoting the mitigation of air
quality impacts through EPA's wastewater construction grants pro-
gram, it is apparent that excess capacity for growth is the princi-
pal issue. However, population growth is not in itself the problem,
but rather, the air quality problem is more related to transporta-
tion. Can a decision by EPA on funding or not funding excess capa-
city for wastewater treatment facilities and interceptor sewer lines
impact in any way the methods individuals use for transportation?
Or will such decisions even effect regional population growth? What
is needed is substantial individual and group commitment to solving
the air pollution problem by reducing automotive use with greater
expansion of transit systems and use of other less polluting modes
of travel. What can EPA do in the actions being considered in the
Environmental Impact Statement to gain this important commitment to
improved air quality? This is a very difficult question, for which
there is no apparent answer when considering the very limited au-
thority of the Federal Government in local land use and transporta-
tion planning decision making.
V-ll
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Public Concern
This discussion of public attitudes in Denver as supported by pre-
vious surveys concerns public feelings towards emission control measures.
The information presented here was taken from the same report referenced
in Section II on public concern.
For controls requiring monetary commitments it was found in two
surveys that about 90% of the respondents expressed some degree of favor-
ableness toward paying $10 per year to reduce air pollution. When raised
to $50 and $100 about 50% responded favorably. In another survey 54%
expressed favorableness toward a $25-$50 tax increase for new transporta-
tion methods in the Denver area, but only 25% were willing to pay $5 for
each trip to downtown Denver.
In one survey 90% of the respondents expressed a favorable attitude
towards annual pollution testing of auto exhausts. Supporting this find-
ing, two other surveys found that 80% and 85% were favorable to a period
of mandatory inspection of emission control equipment. Also, three out
of four respondents in the first survey mentioned in this paragraph
were generally in favor of reducing downtown Denver traffic, although
this figure fell to 64% if such a reduction meant limiting their own
driving. Almost 80% said they were favorable to the idea of taking a
bus downtown, and, in general, the respondents were not in favor of
building more freeways or increasing traffic speeds as a means of lessen-
ing traffic congestion. Regarding the acceptability of various proposals
for reducing congestion, the prohibition of traffic and parking in cen-
tral business districts and the conversion of some lanes to "bus only"
or "car pool only" lanes on major traffic arteries were most acceptable
but given a mean rating of only "somewhat acceptable." Proposals for
gas rationing and a $500 automobile registration fee were given a mean
rating of "very unacceptable."
Results from surveys in other parts of the United States generally
support these findings for Denver, of the public's expressed willingness
to make certain kinds and degrees of sacrifice to promote air pollution
control.
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MITIGATION OF WATER QUALITY IMPACTS
The various strategies for control of point and non-point sources
of water pollutants which were evaluated in the EIS will not result
in water quality which will meet 1983 goals of "fishable, swimmable"
waters. Thus, it is necessary to consider additional measures which
may be taken.
Although future water quality will be influenced primarily by
non-point sources, phosphates are an exception, point source control
is necessary to achieve water quality goals during low flow periods
and downstream from the Metro discharge to the South Platte. It is
also possible that the water quality goals themselves are unrealistic
or inappropriate for the Denver Region. Within these contexts, the
following mitigation measures are evaluated.
Revise Water Quality Goals
The present water quality goals for most of the streams in the
region were established to permit water contact recreation, warm
water fishery, good aesthetics (appearance and odor), animal water-
ing, irrigation and use of stream waters for water supply. If goals
were reduced to include a smaller range of stream uses and benefits
such as non-contact water recreation, warm water fishery, aesthetics
and all other uses except as a domestic water supply, the goals would
still not be met year around. Further relaxation of the goals would
severely limit the recreational potential of streams, a resource of
increasing importance in the future, and seriously impair domestic
water supplies vithin and downstream of the Denver region. Thus, it
may be possible to reduce the degree of control necessary for point
and non-point sources of pollution and related costs by revising
water quality goals, but the overall advantage appears small.
Improved Wastewater Treatment
Improving the water quality of discharges from wastewater treat-
ment plants over and above that considered in the EIS or the Clean
Water Plan would further improve stream water quality during low flow
periods in general. However, a very effective non-point source con-
trol program would also be necessary to meet year round water quality
goals. Phosphates are the only pollutant that will be dominated by
point sources in 1983. All other pollutants are dominated by non-
point sources contributing to water pollution upstream of the Metro
discharge. Metro discharges of BOD, phosphates, and ammonia will
be the dominate source of these pollutants in the South Platte down-
stream of the Metro discharge point. The quality of water when dis-
charged to streams from municipal and industrial wastewater treat-
ment plants, which would result in substantial achievement of water
quality goals in association with non-point source control would
V-13
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have to be BOD, 5 mg/1; suspended solids, 5 mg/1; ammonia, 1 mg/1;
phosphates, 0.3 mg/1, and total nitrogen, 2 mg/1. When discharges
were not to streams, as for urban and agricultural irrigation,
discharge quality should be BOD, 20 mg/1; suspended solids, 20 mg/1;
ammonia, 3 mg/1; phosphates, 8 mg/1; total nitrogen, 5 mg/1; and
TDS, 500 mg/1.
Non-Point Source Control
It has been estimated that in conjunction with high levels of
point source treatment, a 75 percent reduction in non-point sources
will be necessary in the South Platte basin, and 60% in the northern
areas, to meet water quality goals. There are two basic approaches
to non-point source controlj structural and non-structural. Struc-
tural control involves the collection, storage, and treatment of
urban runoff waters. Non-structural control involves such programs
as more frequent and effective street sweeping, controls on domestic
animals,greater litter controls, maintenance and cleaning of street
catch basins, etc. The Clean Water Plan recommends a non-structural
approach which, if implemented effectively and uniformly, is esti-
mated to reduce non-point sources of pollutants by 30 percent. A
structural approach was not recommended because of high cost and
doubtful effectiveness. As a consequence, an expanded water quality
monitoring program was proposed to more specifically identify non-
point sources which in turn would permit the formulation of tailored
and effective control measures.
Development and Growth Controls
Future water quality problems in the majority of the Denver region
will be dominated by non-point sources of pollution even if the non-
structural control program recommended in the draft Clean Water Plan
were implemented and effictive, Future structural controls are like-
ly to be limited to commercial and industrial areas of the region as
there is significant evidence that the majority of a number of non-
point sources of pollution originate from these areas. An additional
category of mitigating measures not considered in the draft Clean
Water Plan is limitation of the amount, type, or location of future
growth.
The upstream portions of the South Platte and its tributaries
beyond the urban fringe have significantly better water quality, and
have the greatest potential for achieving water quality goals. Pro-
tection of these upstream areas can be achieved by stringent develop-
ment controls which would:
1. Prohibit floodplain development and/or require a 200
foot stream setback.
V-14
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2. Minimize impervious areas and vehicle use,
3. Provide for temporary on-site storage of runoff for
eventual percolation into the soil.
4. Provide for the collection and temporary storage of
initial or low volume runoff from commercial and
industrial sites for eventual discharge and treatment
by wastewater treatment plants during off peak hours.
5. Ban the use of septic tank leach fields,
6. Institute other non-structural controls as described
in the draft Clean Water Plan.
Agricultural Reuse and Return Flows
The use of treated wastewater for agricultural irrigation is
generally restricted in this country. This is because of possible
health effects on both farm workers and the consuming public, and
because of possible damage to agricultural soils. At the same time,
the effects of agricultural return flows, classed as point sources,
on stream water quality have not been investigated principally be-
cause no data on return flow water quality is available. As point
and non-point controls are instituted, and agricultural reuse be-
comes more common, the importance of agricultural irrigation return
flows will probably increase. Because of potential health, soil,
and stream water quality impacts, the following measure should miti-
gate or control these impacts.
1. Establish irrigation water quality criteria necessary
to protect the public health and the agricultural soils
of the region.
2. Determine the current water quality of agricultural return
flows and establish discharge requirements if necessary.
Regional Monitoring System
Although water quality monitoring is not a mitigative measure, per
se, the 208 plan recognizes the importance of having an adequate data
base from which to require the implementation of specific point and non-
point control. Consequently,- DRCOG has proposed a regionwide sampling
network which consists of 30 sampling sites. Of these stations, 18 would
be located so as to better define non-point source problems in the 208
study area. Presumably, once the relationship between man's activities
and the resultant non-point source pollution is better quantitied, structural
control of nonpoint source pollution will be instituted where effective
and economically feasible.
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MITIGATION OF AGRICULTURAL IMPACTS
Mitigating measures presented to mitigate growth and other impacts
particularly for soil erosion, are pertinent to the mitigation of
agricultural impacts. The following measures are presented in addi-
tion to those mitigating measures.
Water Conservation
Conservation of available water supplies can be effective in
reducing competition for available supplies, Conservation efforts
in the domestic and industrial use of water can reduce demand 20-
30 percent from current levels. This would greatly relieve pres-
sures to convert agricultural water rights to municipal uses. Con-
servation efforts in three broad areas would be effective:
1. Continuing public education programs on the need and
ways of conserving water.
2. Metering of all water users so that excessive use can
be determined and water conservation measures enforced.
3. Establish water use goals with a regressive rate structure
for excessive use,
4. Ban the sale and installation of water using appliances
that use excessive amount of water, e.g., ban the sale
of flush toilets with tank capacity greater than three
gallons.
Change Water Laws
It would seem effective to amend Colorado Water Rights laws to
require that municipalities meet certain requirements and demonstrate
they have exhausted all available alternative remedies to their
water supply problems. These remedies to include water reuse and/or
exchange agreements, water conservation, land use planning, and de-
velopment controls. This is more stringent than HB 1555 enacted by
Colorado in 1975.
Agricultural Land Transfer Tax
Various proposals and state laws 'in the United States have ad-
dressed the problem of agricultural land preservation. One proposal
which appears to offer an effective mechanism is an agricultural
land transfer tax. This basically involves a tax that would be
levied when title or zoning is change for some use other than agri-
culture. This tax would be payable by the buyer and/or individual
requesting a change in zoning classification.
V-16
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MITIGATION OF ENERGY IMPACTS
Natural Gas Shortfalls and Their Effects on Urban and Rural Users
Because the Denver region has nearly 60 percent of Colorado's
population, its market demand and political influence could affect
the equitable distribution of the state's natural gas when supply
shortfalls begin. State and federal energy allocation planning
will be needed to assure that uses outside the region receive
their fair share of available supplies. Also, within the region,
planning will be needed to deal with supply and demand problems
of electrical energy to minimize brown-outs or load reductions
and shedding.
Secondary Impacts of Natural Gas Shortages on Electrical
Power Generation
A major consideration of any statewide energy planning is that
coal will be the main substitute for natural gas in the generation
of electric power because of the general unacceptability of nuclear
power at this time. Coal mining and processing activities and coal-
fueled generating plants use vast amounts of water. Energy planning
must consider the resolution of water use allocation problems that
will occur in the near future due to coal production and use.
Regional Energy Conservation
Energy conservation is a recognized necessity throughout the
country. The measures listed on Table V-A could be especially use-
ful in the Denver region if implemented by appropriate authorities
and accepted by the general public.
Energy Use in Wastewater Treatment Plants
The mitigations listed in Table V-B should be considered along
with others during facilities design phases to assure that new and
existing facilities will be as energy efficient as current feasible
technology will allow. Back-up power generating equipment should be
installed in existing and new facilities to anticipate power overages,
Table V-B. ENERGY CONSERVATION MEASURES FOR
WASTEWATER TREATMENT FACILITIES
Mitigation Remarks
Use of- solar energy and in-house WWT plant process selection,
generated methane. design, plus solar power and
methane could reduce natural
gas demand by 90 percent for
new facilities, 50 percent
for existing.
Fretreatment of large in- Reduces the energy demand of
dustrial source wastes. wastewater treatment plants.
V-17
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Table V-A. ENERGY CONSERVATION MITIGATION MEASURES
Mitigation
Remarks
Co
Energy conservation and solar use
a. Residential/commercial conservation
b. Industrial conservation
Farm management controls
a. Runoff and erosion controls
b. Water reuse
c. Control fertilizer use in critical areas
d. Require biodegradeable fertilizers, herbi-
cides, etc.
e. Restrict livestock/land ratios
f. Treat irrigation return flows
g. Increase penned animal controls for <1,000
head
Collect and recycle auto oil
Auto inspection and maintenance
Development controls:
a. Require high density development
Water conservation
a. Volume control devices
b. Low volume flush toilets
c. Low volume showers
d. Low water demand landscaping and house-
hold devices
e. Public education and reduce infiltrations
f. Meter with regressive rate structure
g. Reuse
Residential, commercial and industrial retrofit plus
conservation measures incorporated into new development
reduce region's energy demand, mostly natural gas, 10
percent in 1980, 30 percent in 1990.
Reduced fertilizer use reduces demand for fossil fuels
used in its manufacture. Water reuse reduces energy
demand, primarily electric power, of water distribution
systems.
Reduces consumption of petroleum fuels/products
Reduces fuel consumption by vehicles by about 5 percent,
demand for petroleum products 4 percent.
Reduces demand for energy 10-20 percent for new develop-
ment.
Reduces energy demand of wastewater treatment plants
through reduced flow. Maximum reduction would be on
the order of 50 percent attainable in 10 years. Also
reduces energy demand of potable and irrigation water
distribution systems.
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MITIGATION MEASURES FOR ADVERSE GROWTH-INDUCED IMPACTS
Most of the mitigation measures described in this section are
beyond EPA's authority to implement. Thus, EPA will have to rely
on other federal agencies and on state and local agencies if the
measures are to be carried out. To this end, EPA may be able to
function as a motivator and technical advisor to help other agen-
cies, particularly those on the local level, to implement many of
these tasks.
Because of the Denver region's complex framework of local govern-
ment, these mitigations will not be uniformly applied, if at all.
Thus, their real-world effectiveness at the present time is unpre-
dictable. Until there is a state-mandated requirement for con-
sistency between regional comprehensive plans and the granting of
local land-use entitlements, no reasonable estimation of these miti-
gations' effectiveness can be made. For this reason, most of the
impacts examined here are considered to be unavoidable. The rami-
fications of these andother unavoidable adverse regional impacts
will be examined in subsequent sections.
Climate
Wind-Transported Dust and Soil Particulates from Construction
Sites
Construction schedule planning by developers and local govern-
mental regulations to require construction site soil stabilization
during the windy season are the most appropriate means to mitigate
this variably significant impact. If local dust and soil particu-
late problems are not being adequately controlled at this time by
existing regulations, it may be in order for local governments to
consider adopting new, more stringent ones in view of the current
drought and its contribution to wind erosion. This could be done
in conjunction with the site stabilization ordinance discussed under
Soils in this section. Assistance to local governments in preparing
new regulations could be made available by DRCOG, the U. S. Soil
Conservation Service (SCS) and the Colorado State Soil Conservation
Board (CSSCB). If this approach is not successful on a regional
level, it may be appropriate for the State to enact such legisla-
tion as would require local governments to adopt and enforce effec-
tive construction site soil stabilization regulations. This approach
is an extreme one which would be warranted only under the most se-
vere combination of heavy, regionwide construction activity, con-
tinued drought resulting in "dustbowl" conditions, and inaction by
local government to control severe wind erosion problems.
V-19
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Increased Potential for Wind Damage in River Valley Wind Corridors--
Local planning and building inspection agencies should define
historic wind damage factors in the river valley wind corridors and
comparatively evaluate existing land use plans and building codes
to determine whether they need revision to incorporate wind damage
prevention measures. Such wind damage prevention measures might
include prohibitions of certain building design features, signing
design and construction standards, requirements for vegetative wind-
rows at new project sites, and structure orientation standards. EPA
Region VIII, the U.S. Department of Housing and Urban Development
or DRCOG could be instrumental in preparing model wind damage pre-
vention standards for the region.
Fog-Related Traffic Problems--
Fog conditions generally have a great areal extent and are
largely unavoidable. Generally, any successful effort to reduce
ealry morning commute traffic volumes will also reduce the poten-
tial for fog-related traffic problems.
Geology
Modification of Landforms and Hillside Construction
Local jurisdictions on the western edge of the region which are
likely to experience hillside construction should evaluate existing
local comprehensive plans and development standards to determine
whether they adequately consider the special engineering, construc-
tion, aesthetic and environmental problems of such construction. If
existing standards are inadequate, local government should revise them
to focus attention on these special problems. EPA Region VIII, the
U.S. Geological Survey (USGS), SCS or DRCOG could prepare a model or-
dinance for use by local governments to aid in this task.
Effects of Population Growth and Development on Significant
and Unique Geologic Structures and Formations—
As part of local comprehensive planning efforts, significant and
unique geologic structures and formations within each jurisdiction
should be noted and adequate plans for their preservation and protec-
tion should be formulated if this has not already been done.
Local Mining and Geologic Hazards to Development—
Significant mining and geologic hazards within each jurisdiction
should be identified, if they have not been already, as a part of lo-
cal comprehensive planning activities. Existing development regulations
V-20
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relative to each type of hazard should be evaluated for effective-
ness and revised as needed. Local jurisdictions should consider
establishing programs to reclaim hazardous surface mining areas,
seal mine shafts and restrict development in areas having subsi-
dence potential because of past subsurface mining activities.
DRCOG, with the help of USGS, should be called upon to help local
governments identify hazardous areas and to develop model ordi-
nances and programs focused on local conditions.
Soils
Increased Agriculture-Related Wind Erosion Due to Current
Drought Conditions—
Mitigations relative to construction site wind erosion were dis-
cussed under Climate. The SCS, through the local conservation dis-
tricts and CSSCB, should step up technical and educational assistance
programs to help local farmers minimize topsoil losses during the
current drought.
Water Erosion—
All jurisdictions in the region should examine their development
standards to determine their adequacy to control erosion and runoff on
construction sites. DRCOG, assisted by SCS and CSSCB, should be called
upon to prepare a model erosion and runoff control ordinance for con-
struction sites as a part of, or as an adjunct to, the current 208 plan-
ning program. This mitigation could be effective to some degree in
reducing the sediment load in the region's drainage net.
Biology
Stream Channelization—
Structural treatments to watercourses are frequently a part of
flood control measures. Stream channelization and related activities
such as diversions and culverting adversely affect the aquatic en-
vironment. Municipalities and flood control districts should incor-
porate the following recommendations into any existing flood control
design standards. Appropriate regional and state agencies should be
called on to prepare a model set of flood control designs based on
these recommendations to aid local agencies, if necessary.
Soft Channel Treatment—Flood protection can be achieved through
alternative means such as broadening the channel and usage of earthen
levees and flood walls to some degree. In this manner, protection is
incorporated without drastic alteration of the stream bottom itself.
This is a compromise measure, for even if vegetation is allowed to
grow back, the channel will have a disturbed appearance.
V-21
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Off-Channel Treatments-—Stream channelization is minimized. In-
stead", combinations of flood-proofing and evacuation of the flood-
plain are adopted. This method should be more effective than soft
channel treatments in protecting the aquatic environment. However,
off-channel treatment generally requires more space.
Nonstructural treatments—Stream channelization and similar
structural methods of flood protection in newly populated areas would
not be used. Protection would instead utilize floodplain zoning,
floodplain insurance, acquisition of land, including conservation
easements, and eventual removal of human habitation from the flood-
plains. These measures go beyond the physical protection of stream
channels, embodying conservation concepts that require policy changes
and, in some cases, legislative action.
Upstream Conversion of Land to Urban Uses—
Mitigations for this effect would be covered in most of the channel
treatments suggested under the preceding subsection. In particular,
non-structural treatments would be most effective and are best suited
for implementation prior to actual upstream land development. Measures
to protect the local stream environments should be incorporated into
the local land use plans. Technical assistance could be provided by
appropriate regional agencies.
Industrial Activities near the Aquatic_Environment—
Discharges from industrial and manufacturing facilities to local
watercourses should require federal and state controls. The National
Pollutant Discharge Elimination System (NPDES) permit system as ad-
ministered by the state is aimed at protection of the local aquatic
environment as well as maintenance of water quality. The impacts of
future gravel mining along floodplain corridors could be minimized by
rigorous local and state governmental standards and regulations. All
mining activities should be required by State law, before local
governmental approval, to prepare plans for protection of streams
during construction and excavation, along with workable plans for re-
claiming the stream channel after mining activities have ceased and
for restoration to a viable riparian environment.
Disruption of Riparian Corridors—
Mitigations for this impact could be required through local com-
prehensive planning efforts and development standards. DRCOG could
provide technical assistance through a set of model development
standards should minimally consider the following recommendations:
V-22
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(1) Design of facilities which minimize stream crossings
or use of areas adjacent to streams.
(2) Inclusion of reclamation activities into the facility
design. Restoration of disturbed areas by revegetation,
re-creation of natural stream bottoms and other methods
would mitigate some of the effects of stream crossings.
However, with frequent human presence, these areas will
always retain a disturbed composition.
Disturbance of Forest and Brushland Areas-—
To protect the foothill and upland areas in the face of future
development, any new development standards should also consider:
(1) Regulation of activities on all public lands specifically
to control excessive ground-cover removal, resource har-
vesting and other human uses.
(2) Legislation applicable to both public agencies and
private landowners on activities which may adversely
affect the environment.
(3) Strict agency supervision of those controls which the
general public and private landowners are required by
law to follow. These include fire control measures, engine
noise control measures, litter ordinances and others,
(4) Comprehensive planning for future land use in undeveloped
and developing areas based on environmental limitations
and opportunities.
Development near Unique Habitat Areas—
Adverse impacts on unique natural areas can be mitigated by:
(1) Official recognition, and designation to a protected
status, where possible, by the appropriate governmental
agencies,
(2) Comprehensive planning by local jurisdictions with technical
assistance by DRCOG near these areas which minimize physical
disturbance or introduction of large numbers of people to
the area.
V-23
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Increased Fire Hazard—
Several structural and nonstructural methods may be used to de-
crease the wildfire potential. These are generally preventive mea-
sures particularly applicable to foothill and mountain areas which
should be instituted during local comprehensive and project develop-
ment planning with the assistance of local, regional and state fire
fighting authorities. Model wildfire hazard reduction standards
could be developed by DRCOG or another appropriate agency. Such
standards should consider:
(1) Thinning of dense tree stands near areas of human
activity. This should be mandatory for homes built
on slopes greater than 30 percent or on unstable
slopes.
(2) Removal of trees close to homes and of branches over-
lapping rooftops, especially those near chimneys.
(3) Removal of extraneous flammable material such as debris
on the ground and along roadsides. Pruning of dead limbs
and removal of branches to a height of 8 to 10 feet near
inhabitied areas would also help,
C4) Prohibition or strict limitation of outside burning.
(5) Provision for adequate access by fire-fighting equipment.
Planning for emergencies, including familiarization with
escape routes.
Aesthetics
The potential indirect impacts mentioned in Section IV can be
lessened or corrected in many ways. However, a long list of suggested
mitigation measures for impacts that may happen in the future cannot
replace comprehensive planning that initially should be done by the
local and regional planning agencies to preclude the occurrence of many
of these impacts. The following is a list of the planning measures
which if considered and implemented at the present time would reduce
adverse aesthetic impacts.
(1) Development controls along stream corridors to protect the
aquatic environment.
(2) Development controls in wilderness areas or natural units
within urban areas to minimize disturbance to sensitive
wildlife and unique ecological areas.
V-24
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(3) Policy controls to limit developments which preclude
public access to surface waters, scenic areas and
recreational resources.
(4) In-depth planning of transportation routes and traffic
circulation patterns which people can relate to and not
feel overwhelmed or frustrated by.
(5) Comprehensive planning which balances the human needs
for open space relationships, aesthetic appreciation
of natural resources and "breathing space" in a modern
environment agianst pressures for urban development
and urbanization.
(6) Environmental protection measures for parameters not
sturcturally definable such as clean air, ease of
movement, visual landscape harmony and others.
Outdoor Recreation Sites
Potential Overuse and Resultant Damage to Existing Recreation
Facilities Due to Population Growth—
Municipalities and their park departments throughout the region
have tended to keep pace with the population's demand for urban re-
creation facilities in traditional terms of developing and main-
taining widely scattered community parks and they will continue to
do so in the near future. To prevent damages to these facilities
from overuse, measures should be taken to provide neighborhood fa-
cilities for the primary, day-to-day needs of the public. Local
governments should require developers to provide neighborhood recre-
ation facilities through integral designs of usable open space in site
plans, construction of neighborhood parks within developments, or
payment of in-lieu-of fees to the local park agencies. DRCOG could
aid those jurisdictions needing technical assistance in the prepara-
tion of appropriate ordinances and development standards.
Park Vandalism—
Model development standards which could minimize vandalism to
park facilities should be prepared by DRCOG to aid local agencies in
upgrading existing recreation sites, and in designing and constructing
new ones.
Land Waste Disposal Sites
The most expedient and effective way to resolve the continuing
land use conflict over sludge disposal at~the Lowry Bombing Range
is to develop and utilize a remote site such as that proposed for
West Adams County as soon as possible.
V-25
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Traffic
The Federal Urban Mass Transit Administration's (UMTA) denial
of funds for a transit system in the Denver region has disrupted
efforts to lessen the region's dependence on the automobile with
an attractive alternative mode of transportation. The Regional
Transportation District (RTD) with the aid of the State of Colorado
and its Congressional delegation should continue seeking funds from
UMTA for a modern regional transit system. This should be done
to influence the extent and pattern of urbanization, conserve energy
supplies and land resources, and take advantage of the economic ef-
ficiencies inherent in mass transit. At the same time, RTD should
step-up efforts to use its bus fleet to the fullest extent by such
means as acquiring exclusive bus lanes for use by short-headway,
express buses; refitting express buses with comfortable, long-
distance seats and maintaining the cleanliness of the entire fleet
to the highest degree; constructing conveniently located suburban
stations having ample, free parking along the express lines (the
stations should be designed to served as fixed-rail stations at a
later time) ; construct "park-and-ride" parking lots around the
periphery of the central business district (CBD) ; and provide
jitney bus service in the CBD. Other suggestions to increase rider-
ship include a high quality, long-term advertising and education
campaign, special event service schedules, simplified fare schedules
such as monthly passes and education of RTD's public contact employees
in the arts of public relations.
MITIGATION MEASURES FOR DIRECT IMPACTS
Climate
Seasonal Climate Events and Conditions Which Could
Affect Facilities Construction—
Delays incurred in construction can be almost wholly avoided by
phasing construction during periods of little or no adversive climate
conditions such as in late spring and summer which is the accepted
practice in the region. Surface disturbances should be limited to
those areas where construction is actually under way. Disturbed
ground surfaces should be sprinkled as needed to control fugitive dust.
And, disturbed ground surfaces should be revegetated as soon as con-
struction is completed.
Aerosol Production and Local Fog Formation—
A aerosol formation and local fog formation can be reduced sub-
stantially by utilizing low-rate, low pressure irrigation systems which
employ large nozzles instead of high rate irrigation systems. Aerosol
V-26
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formation can be effectively reduced to zero by using drip irrigation
instead of spray irrigation systems but this latter is prohibitive-
ly more costly.
Disruptions in Utility Services and Other Wind-Related
Impacts on the Operation of Facilities—
Interuptions of electric power service could be reduced by placing
all utilities underground. This can be more costly initially than con-
structing overhead lines, but it is less costly to maintain. Under-
grounding requires only temporary alteration of the site. Wind damage
to facilities can be reduced by surrounding treatment plants and ponds
with vegetative windrows and/or berms. Berms would reduce possible
adverse effects more than windrows but would be more costly to con-
struct and would require more extensive alterations of existing vegeta-
tive cover and terrain. If windrows and berms are integrated into a
facility's landscaping plan, they can be a positive aesthetic feature
on the project site.
Geology
There were no direct impacts assessed for site-specific geologic
conditions. Any significant site-specific conditions discovered during
the design phases of the proposed facilities should be mitigated at
thattime by qualified professionals.
Soils
Wind Erosion Impacts—
Mitigation measures for direct impacts of wind erosion were dis-
cussed under Climate, Seasonal Events and Conditions Which Could Af-
fect Facilities Construction.
Water Erosion Impacts—
Erosion and runoff control plans should be prepared as a part of
all facilities construction plans,
Biology
Disturbance of Loss of Vegetation and Wildlife Habitats—
Construction of the treatment plants and pipelines under all alter-
natives will involve removal of natural and introduced vegetation from
construction sites. Wildlife utilizing these areas would also be
disturbed form their normal patterns. Mitigation measures would in-
clude :
V-27
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Limitation of construction activities, stockpiling of materials
and- personnel to the construction site only—This action would
minize adverse effects on adjacent areas.
Design and placement of structures in areas of marginal habitat
or that are already commited to human uses—This type of planning
minimizes disturbance of natural areas by using existing roadways and
urbanized areas,
Construction practices which preserve on-site vegetation and habi-
tats to the maximum extent possible—The integration of existing
natural vegetation into the project areas would preserve some wild-
life habitat as well as facilitate recovery after construction. Re-
tention of trees and ground cover, where possible, would also help
stabilize the soil structure, Channel work, where necessary, should
not be based on "high" velocity flows, but in general upon design
velocities similar to present natural stream characteristics.
Reclamation program for construction sites—As soon as it is
feasible after completion of construction, the exposed terrain could
be regraded to a natural or semi-natural landform and revegetated.
Restoration of ground cover, particularly native species, would facili-
tate return of some wildlife species, Due to the initial construction
disturbance, sensitive species may migrate permenently to other areas,
Thus, the level of success for this mitigation caction is the return
and colonization of species tolerant to an altered human environment.
Disturbance of Aquatic Habitat During Construction—
Mitigation measures to minimize disturbance of the aquatic
habitat include;
Limitation of construction activities to construction site only—
Disturbance of the minimum amount of habitat during outfall construc-
tion could substantially reduce aquatic impacts.
Construction practices maximizing protection of the aquatic environ-
ment— Revegetation or some type of structural treatment to exposed
stream banks is important to prevent bank erosion and restore a riparian
stream environment. In areas where the stream channel has been greatly
disturbed, the recreation of stream habitats such as rock beds and pools
along with removal of debris would hasten the return of an aquatic
equilibrium to the stream environment.
Effects on Aquatic Environment During Facilities Operations—
The diversion of some effluent flows to local creeks due to the
abandonment of local treatment plants would adversely affect the water
regime in the local stream environments. This problem, coupled with
V-28
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legal water rights problems involving water supply to downstream water
users, may require some insurance of maintenance of stream flows. Thus,
measures which allow for a compensating upstream water release, if pos-
sible, would mitigate this impact to some degree.
Traffic
Because no significant adverse effects are anticipated, no miti-
gation measures are recommend.
Historic Features
Facility planner should plan all phases of materials delivery
and construction so that historical sites and districts near the
project site and along all thoroughfares to the site will be avoided
whenever possible. The State and Federal procedures for preservation
of historic and archeaologic preservation will be adhered to.
Outdoor Recreation Sites
The facility planner for each proposed project should investigate
the site and its surroundings for any recreation sites that might be
affected by construction 01; operation of the facility. When there
is a possibility of impact, the facility planners and the responsible
agency should be required to contact the appropriate recreation agency
to work-out a mutually acceptable set of solutions to problems which
might arise.
Aesthetics
Construction Effects
Mitigation measures to ameliorate the aesthetic impacts of_ con-
struction are in most cases covered under physical impact mitigation
in other sections. In brief, these includej
(1) Dust control measures during earth-moving such as water
sprays.
(2) Emission control devices on heavy machinery where feasible.
C3) Careful scheduling to minimize disruption of human land use
patterns.
(4) Conducting a public relations program prior to and during
construction to keep public informed of project status and
anticipated degree of impact to local community.
V-29
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Operation Effects—
The aesthetic impacts of was-tewater treatment facilities operations
can be mitigated by the following measures s
CO Design phase considerations to plan the wastewater facilities
in a manner which can be compatible with the local area land-
forms, architectural context and natural context,
C2) Operation activities and scheduling which minimize noise, odors,
night-time lighting and vehicle and personnel movements.
C3) Appropriate landscaping or architectural design around
treatment plants which either mask the structures or draw
attention away from them.
(4) A public relations program which informs the public about
plant operations. In some cases, excess public land at the
treatment plant site can be developed in public recreation
and multiple-use areas.
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VI. Unavoidable
Adverse Impacts
-------
SECTION VI
UNAVOIDABLE ADVERSE IMPACTS
REGIONAL UNAVOIDABLE ADVERSE IMPACTS
1. The region will continue to grow in both population and
urbanized areas at the expense of existing and potential agricultu-
ral areas. The existing, complex framework of government agencies
will hinder the solutions of region-wide problems.
2. Urban sprawl is expected to continue with the migration of
the affluent and advantaged to the suburbs. Out-migrants from the
urban core will be replaced in large measure by the poor, the old,
minorities, and the disadvantaged. Economic growth in the suburbs
will be more rapid than in the urban core. Physical and economic
decay of the urban core is expected.
3. Damage to park and recreational facilities resulting from
overuse or vandalism will continue and intensify as park acreage
per capita ratio decrease.
4. Public health and soil damage impacts will occur as a con-
sequence of agricultural irrigation with wastewater treatment plant
effluent unless State of Colorado and local public health and agri-
cultural officials establish effective effluent quality standards.
5. Particulate air pollution concentrations can be expected
to increase in future years resulting in continued violation of the
National Ambient Air Quality Standards. The major sources for par-
ticulates will continue to be related to construction activities,
and materials on streets thrown up by vehicular traffic.
6. With the implementation of a vehicle emission inspection
and maintenance program, carbon monoxide concentrations on a re-
gional scale will be near to but still exceed standards in 1985.
Peak ozone concentrations will continue to violate standards for
the same year. By the year 2000, carbon monoxide on an average
regional basis will meet standards, but high volume traffice cor-
ridors and interestions will continue to have "hot spot" carbon
monoxide violations. Peak ozone concentrations will be near, but
still occasionally exceed standards. The high per capita usage
of the automobile by residents of the Denver region will continue
VI-1
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to be the major source of carbon monoxide, ozone and parti-
culates pollution.
7. The implementation of any of the three major alternatives
or the recommendations of the Clean Water Plan will likely result
in an improvement in existing stream quality, but not in a degree
sufficient to meet 1983 goals.
8. The region will experience natural gas supply shortfalls
by 1978-1979.
9. Increased dependence on coal for electrical power genera-
tion will create new water allocation and quality problems.
10. Energy is not likely to be conserved to the degree
necessary to avoid natural gas supply shortfalls or to reduce the
region's future dependence on coal-generated electricity.
11. Construction site erosion and runoff will continue to
be an important short-term impact on water quality throughout the
region.
12. Stream channelization and related activities such as
diversions and culverting in newly developing areas will adversely
affect the aquatic environment at points throughout the region,
particularly in upstream locations.
13. Industrial and mining activities along the region's
streams will continue to adversely affect riparian and aquatic
habitats.
14. Continuing development of all types will disrupt riparian
corridors.
15. Future development in foothill and upland areas will
disturb the habitats and ranges described in Section IV.
16. A number of unique habitat areas will be disturbed by
future development, overuse of sites, trespassing and vandalism.
17. The Regional Transportation District will continue having
difficulties competing with the automobile and achieving the
utilization of its bus fleet until such time the automobile be-
comes an economically undesirable means of transportation.
18. Susceptibility to losses to topsoil and economic losses
in agricultural sector under drought conditions is likely to in-
crease.
VI-2
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19. Continued development in wind corridors will increase
the potential for Chinook-related damages to some degree.
20. Increased traffic volumes on stream valley thorough-
fares will increase the occurence and severity of fog-related
traffic problems.
21. Aesthetically unattractive and potentially hazardous
hillside development is likely to occur in some jurisdictions,
22. Some significant and unique geologic structures and
formations in the region are likely to be damaged or defaced by
overuse and vandalism.
23. Some mining-related hazards will threaten the safety and
well-being of local residents in some jurisdictions.
UNAVOIDABLE ADVERSE IMPACTS OF WASTWATER FACILITY
CONSTRUCTION AND OPERATION
1. Aerosols and local fogs will be produced at the facilities.
2. Erosion and run-off impacts would likely be unavoidable
if the wastewater treatment plant construction-related mitigation
measures recommended in Section V, Mitigation Measures for Direct
Impacts, are not carried out.
3. Construction will eliminate human-sensitive wildlife species
from the project sites.
4. Treatment plant odors should be considered an unavoidable
impact because of the unexpected nature of the climate and opera-
tions upset conditions resulting in their production.
VI-3
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-fw.
VII. Short-term Uses
vs. Long-term
Productivity
-------
SECTION VII
LOCAL SHORT-TERM USES VERSUS MAINTENANCE AND
ENHANCEMENT OF THE LONG-TERM PRODUCTIVITY OF THE ENVIRONMENT
1. The proposed projects under all three alternatives
would improve the region's water quality. The local and no-action
alternatives would result in marginally better water quality on a
region-wide basis than would be the case for the regional alternative.
However, 1983 standards will not be met by any of the alternatives
alone nor by the recommendations of the Clean Water Plan. This is
because nonpoint sources of pollution become even more controlling
as regional growth continues. The review of the nonpoint source
situation in this EIS reveals that nonstructural control measures
alone are inadequate to reduce this category of pollutants if
historic forms of urbanization continue, and that costly structur-
al control measures will be required if standards are to be met.
Thus, water quality improvements achieved with point source controls
may well be short term in nature.
2. All three alternatives and the Clean Water Plan will
provide additional sewer capacity to accomodate the growth, and
attendant impacts, expected in the region. The local and no-
action alternatives, however, may reduce the ability of some
future regional government to use sewer facility construction as a
tool to control the rate, distribution and density of development.
3. Tax monies payed by the residents of the region will be
returning to the region to improve water quality and provide jobs,
both of which will have beneficial effects on the regional economy.
The local alternative would generate about 4,100 person-years of
construction employment over the next five to six years, and the
regional alternative, about 3,900 person-years of construction
employment. All alternatives would mitigate construction trades
unemployment, and maintain pressure from this economic sector for
further urban development.
4. The local and no-action alternatives facilitate water
reuse and augmentation of local stream flows. Flow augmentation
will improve riparian and aquatic ecosystems, and aesthetic and
recreational opportunities. However, a dependance on these aug-
mented flows will result in a tendency to foreclose future options
for use of water resources. These alternatives would also reduce
water rights disputes as treated wastewater would be in closer
VI I-1
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proximity to agencies wishing to maintain or exercise those
rights, thus promoting water reuse and successive use in a region
with water resource problems.
5. The no-action alternative would increase the financial
burden of agencies and districts responsible for wastewater collection
and treatment by about $70 million over that occurring under the
other alternatives. This would ultimately impact residents of the
region through increased user charges. This may result in a decreased
willingness or capacity for residents to support other public
service and/or facility costs particularly in the city and county
of Denver.
6. Future urban growth in the Denver region will absorb
38,000 acres of prime agricultural land. Further economic and
physical decay of the urban core is also likely. Thus, short
term benefits will occur to suburban communities and associated
developments to the long term detriment of agricultural productivity
of the region and of the urban core.
VII-2
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VIII. Irreversible and
Irretrievable
Commitments
of Resources
-------
SECTION VIII
IRREVERSIBLE AND IRRETRIEVABLE COMMITMENT OF RESOURCES
Implementation of any of the alternatives will require an
irretrievable consumption of construction materials, fuels, labor
and funds.
All alternatives would support planned future growth in the
region, with its implied commitment of resources. Federal partici-
pation would be diminished under the no-action alternative. Under
the other alternatives, federal participation in the following
growth-related irreversible and irretrievable commitments of resources
would occur:
(1) Conversion of prime agricultural lands and open space
to urbanization;
(2) Consumption of limited petroleum-based liquid fuels in
the construction of facilities and by the transportaion
system; also, commitment to inadequate supplies of natural
gas, upon which the residential, commercial and industrial
sectors are very dependent;
(3) Increased commitment of available water to urban uses in
an area of the nation constrained by limited water re-
sources.
VIII-1
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IK. Coordination and
Public Involvement
-------
SECTION IX
COORDINATION AND PUBLIC INVOLVEMENT
A Technical advisory Committee was established to assist
and advise in the preparation of the draft Environmental Impact
Statement. Membership was made up of representatives of local,
regional, state and federal agencies, and citizen groups. The
TAC's membership consisted of:
Mr. Gary Broetzman
208 Coordinator
State of Colorado
Mr. Walt Kelm
U.S. Department of Housing
and Urban Development
Mr. David Klotz
Denver Regional Council
of Governments
Ms. Purnee McCourt
Colorado Open Space Council
Mr. Robert Moore
U.S. Bureau of Land
Management
Mr. Warner Reeser
Colorado Air Pollution
Control Division
This draft EIS was also coordinated with the Federal Regional
Council, made up of representatives from federal agencies in the
region.
A major compaign will be conducted during the public review of
this draft to inform and promote the involvement of the general
public. Special presentations will be made to selected governmental
and citizen groups, and general presentations made to as many groups
as can be accomodated. Print and broadcast media contacts will be
made and materials furnished to effect widest possible coverage of
Mr. Leonard Slasky
Colorado Department of Highways
Mr. Larry Smith
Federal Highway Administration
Mr. Kenneth Webb
Colorado Water Qualtiy Control
Division
Ms. Toni Worcester
League of Women Voters
Mr. Ken Slyziak
Regional Transportation District
IX-1
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the draft EIS. A special newspaper supplement will be distributed
by regional newspapers to inform the public and encourage attendance
at a public hearing.
The 208 program has had its own public involvement program.
Included in this element of the 208 program are:
(1) Community workshops, meetings, etc.
(2) Water Quality Advisory Task Force monthly meetings
(3) 208 presentations at local service clubs, schools, etc.
(4) Development and distribution of handouts, television
public service spots, slide shows, etc., and
(5) Series of public meetings followed by a public hearing to
consider the "Plan Report".
Despite the efforts of DRCOG to obtain public interest in the
Clean Water Program, widespread knowledge of the project does not
exist throughout the Denver area.
IX-2
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--.—
K. Significant Issues
to be Resolved
-------
SECTION X
SIGNIFICANT ISSUES TO BE RESOLVED
Water quality goals will not be met by any of the proposed
alternatives, singly or in combination with the recommendations of the
Denver Water Quality Management Plan (208 Plan). Even though DRCOG
worked with over sixty agencies in developing the plan, there is no
assurance that the 208 Plan recommendations will be carried out, given
the complex institutional setting of the Denver region. Without such
assurance, the long-term value of EPA investments in treatment level
and capacity of municipal wastewater treatment plants in the region
is open to question.
Actions of other federal agencies may minimize the effectiveness
of EPA, state and local actions to improve water quality and mitigate
adverse environmental impacts resulting from the continuation of histor-
ic forms and patterns of urban growth. Such patterns result in ad-
verse environmental impacts regarding, air quality, loss of prime
agricultural land and competition for available water and energy re-
sources. The mechanism for effective coordinated federal action by
all agencies has yet to be developed and remains at issue.
As discussed throughout this document, air quality is fore-
casted to improve over the next two decades, with the exception of
particulates. However, standards for CO and ozone will continue
to be exceeded over much of this period. No air quality projection
has been made for Denver beyond the year 2,000, and the impact of
pollutant emissions in Denver on downwind residents is also yet to
be determined. This situation of continued air quality problems
will continue to impact the health of the Denver region populace.
While the major source of the problem has been identified as the
automobile, present projections indicate increased vehicle usage in
the Denver region. Federally required emission controls and the
possibility of an emissions inspection and maintenance program are
expected to be the principal strategies for reducing pollutant
concentrations. For particulates, vehicle emission controls will
not impact future concentrations and the present problem is expected
to get worse.
Following are some of the remaining significant issues concerned
with air quality downwind of the Denver Region.
(1) Air quality forecasts were limited to the Denver region.
Air quality 50 to 150 miles downwind of the Denver region may not
improve.
X-l
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(2) The increase in particulates may cause small but signi-
ficant climatological changes downwind from Denver.
(3) Increased use of coal as fuel for stationary sources and
as a replacement for oil and natural gas may result in higher levels
of pollutants, particularly sulfates and particulates.
These considerations raise issues yet to be resolved about future
air quality downwind of the Denver region.
In the context of the proposed waste water facility funding
being considered here, there appears to be no clear cut approach
for EPA to address this air quality problem other than the no-
action alternative. However, the no-action alternative is not
expected to significantly change the future situation either in^
terms of air or water quality and would only limit Federal parti-
cipation in the future. What is needed is a commitment by indivi-
duals and private and public institutions to reduce dependance
upon the automobile. Potential gasoline shortages and higher
prices may eventually induce this change in life style without
this prior commitment to significant air quality improvement.
Implementation of many of the mitigation measures discussed earlier
will be a difficult task at best, due to the multi-jurisdictional
problems that exist within the Denver Metropolitan area. In fund-
ing wastewater treatment systems, many times EPA works directly
with special Sanitation Districts that serve, but are not tied
directly to, municipal governments. In these cases, this relation-
ship restricts EPA's ability to negotiate special conditions which
might mitigate certain specific adverse land use impacts. Additionally,
there is no regional authority presently responsible for control of
nonpoint pollution from urban runoff. Therefore, the present improve-
ment of water quality, through control of both point and nonpoint
pollution sources, is effectively limited by the Jack of a nonpoint
source management agency. These jurisdictional and management dif-
ficulties are not limited to water pollution control but also include
areas of water supply, flood control, recreation, regional development,
transportation, air quality, agriculture, and others involving the
region's social welfare. Consolidation of responsibilities or other
measures to develop regional responsibility and authority, such as
discussed under the Section on Mitigation Measures, appear to be the
most effective means to gain more effective implementation of worthy
environmental mitigation measures.
X-2
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HI. Glossary and
Bibliography
-------
SECTION XI
GLOSSARY
Activated sludge—A process which removes organic matter from sewage
by saturating it with air and adding biologically active sludge.
ad valorem tax—A general property tax levied annually on real and
personal property as listed with the county assessor.
Aerosol—A suspension of fine solid or liquid particles in a gas.
In wastewater treatment processes involving spraying, aerosols can
transport micro-organisms and dissolved liquids in the wind for
considerable distances.
Aggregate—Any of several hard, inert materials, such as sand,
gravel or slag, used for mixing with a cementing medium to form
concrete, mortar or plaster.
Agricultural multiplier—A term which describes the number of times
money generated by the agriculture sector of a regional economy
changes hands before leaving that economy.
Anaerobic digester—A type of equipment used to digest sludge in
the absence of oxygen to reduce the volatile organic material to
methane gas by microbial activity.
Aquatic environment—The ecologic conditions extant in the region's
streams and water bodies.
Aquifer—A water-bearing stratum of porous rock.
Benthic organisms—Organisms which live on the bottoms of water
bodies.
Berm—A structure resembling a dike which is used as a means of
physical separation.
XI-1
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BOD —An abbreviation representing the amount of oxygen required
for the biological decomposition of dissolved organic solids to
occur under aerobic dontions for five days at 20 C.
Braided stream—A stream with an interlacing network of channels.
Brown-out—A period of reduced illumination resulting from demands
for electric power which exceed generating capacities.
Carbon monoxide (CO)—A very toxic, colorless and odorless gas.
Carrying capacity—A relationship reflecting the number of animals
and/or humans that a given unit of land can support with a
substantial degradation of that land unit's extant conditions.
cfs—An abbreviation for cubic feet per second. It is a unit of
measurement commonly used to describe volume of streamflow.
Dewatering—A process where sewage is reduced in volume by removing
a portion of its water content.
Diurnal—A term used to describe a 24-hour cycle.
Effluent—The liquid that comes out of a treatment plant after
completion of the treatment process.
Emissions—Substances discharged into the air.
Environmental limitations—Those features of a defined area of
land which could be degraded if new land uses were introduced.
Environmental opportunities—Those features of a defined unit of
land which provide distinct advantages to certain introduced land
uses.
Epidemiological—The sum of the factors controlling the presence or
absence of a disease or pathogen.
Eutrophication—A process by which a body of water becomes overly
rich in nutrients and deficient in oxygen.
Fugitive dust/particles—Dust and soil particulates carried by winds
away from an earth disturbance.
XI-2
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Gaussian plume model—A mathematical model used to predict the
distribution and dilution of air-borne substances from stationary
sources.
General obligation bonds—Bonds secured by the full faith and
credit and by the general taxing power of the issuer.
Holistic—A view that nature is correctly seen in terms of
interacting wholes that are more than the mere sum of elementary
particles.
Hydrograph—A graphic presentation of quantified streamflow
characteristics.
In-liew of fees—As used in this document, recreation facility
in-lieu of fees would be payed by residential developers, if they
were not required by local jurisdictions to provide outdoor
recreation facilities within their developments. The monies
collected would be used by local jurisdictions to develop parks
and playgrounds.
Interceptor—Interceptor sewers in a combined system control the
flow of the sewage to the treatment plant. In a storm, they allow
some of the sewage to flow directly into a receiving stream. This
protects the treatment plant from being overloaded in case of a
sudden surge of water into the sewers. Interceptors are also used
in separate sanitation systems to collect the flows from main and
trunk sewers and carry them to the points of treatment.
Intermittent stream—A stream which flows only during a part of a
year. This contrasts with perennial streams which flow all year
and ephemeral streams which carry only stormflows.
Inversion (temperature)—A reversal of the normal atmospheric
temperature gradient.
Isopleth—A line on a map connecting points at which a given
variable has a specified constant value.
XI-3
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Mill levy—An ad valorem tax.
Mini-NEPA laws—State and local laws, such as the California
Environmental Quality Act, which are modeled after the National
Environmental Policy Act to assure environmental review of state
and local actions which might adversely affect the quality of the
environment.
NO, NO and NO —Oxides of nitrogen which are significant contri-
£ X
butors to the formation of photochemical smog.
Non-point source—An activity distributed over a wide area that is
a source of pollution.
Nonstructural control measures—Regulations and maintenance
activities which reduce the production of pollutants without
relying on equipment or facilities specifically designed to reduce
the target pollutants.
Ozone (0_)—A major agent in photochemical smog,
Particulate matter—Any material, except uncombined water, that
exist in a finely divided form as a liquid or solid.
Perturbation—As used in this document, a perturbation is a
hypothetical disturbance or change to extant conditions for the
purpose of comparative modeling.
Point source—A stationary, readily identifiable pollution source.
Potable water—Drinkable water.
Precursor—A substance from which another substance is made.
Prototype meteorological day—A day whose quantified weather
characteristics are representative of an area. These characteristics
are used in mathematical models of air pollution conditions.
Radiation fog—A ground fog produced when the dew temperature
(point of condensation) is reached through direct radiation of
ground heat.
XI-4
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Revenue bonds—Bonds secured by a pledge of revenue which is to
be derived from the operation of a public facility.
Rilling—A form of water erosion where very narrow and shallow
furrows are created on exposed ground surfaces.
Riparian corridors—-Biotic communities along stream courses used
by wildlife as movement corridors.
Riparian habitat—A streamside biotic community.
Sedimentation—The process of particulates settling out of their
transporting medium, e.g., silt, sand and gravel settling to the
bottom of a stream.
Sediment load—The amount of particulates carried in a transporting
medium.
Seismic activity—Earth shaking and movements.
Septic tank leachate—The incompletely treated liquid component of
sewage processed by a septic tank.
Service/user charges—A regular charge levied on sewer system users
by a responsible agency for the provision of services.
Setbacks—A land use restriction commonly employed for a number of
health, safety and environmental reasons to prevent or limit
construction in a given area, ususally to provide a buffer zone.
Shedding—Load shedding is a prearranged action by electrical power
supplier and their major consumers where voltage is cut back by the
supplier to the consumer or power demand is reduced by the consumer
to prevent system-wide power shortfalls.
Sheet erosion—Soil erosion where water draining from an exposed
ground surface does so in wide, even "sheets" and thus does not
form any rills, rivulets or gullies.
Shortfall—As used in this document, a shortfall is a failure to
meet an energy need.
XI-5
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Shrink-swell—A characteristic of soils containing clay which
describes the range of volumes per unit weight of soil under wet
and dry conditions.
Sludge—Sludge is the solid matter that settles to the bottom,
floats or becomes suspended in the sedimentation tanks and must
be disposed of by filtration and incineration or by transport to
appropriate disposal sites.
SMSA, Standard Metropolitan Statistical Areas—Geographical units
of land established by the U.S. Census Bureau to aid in its population
data collection and analysis activities in urban areas.
Stationary sources—Nonmobile air pollution sources, e.g.,
refineries and factories.
Steppe—An arid, mid-latitude, continental natural region characterized
by vast, flat and treeless expanses.
Strata—Sheets of sedimentary rock or earth covering one another.
Stream channelization—A human activity intended to modify natural
stream channels to increase their volumes of flow.
Structural control measures—Facilities or equipment, such as
wastewater treatment plants, which are specifically designed and
constructed to abate a given pollution problem.
Subsidence—An event or occurrence where the ground surface settles
or sinks to a new level.
Suspended solids—The small particles of solid pollutants which are
present in sewage and which resist separation from the water by
conventional means.
Synergistically—Several discrete agents having the ability to
cooperate such that the total effect is greater than the sum of the
agent's effects taken independently.
Tap fees/Connection fees—Initial fees charged by a sewer agency to
allow connection to a sewer system.
XI-6
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Transition Life Zone—-A term categorizing environmental
characteristics found between 5,500 feet and 8,000 feet elevation.
Trickling filter—A support media for bacterial growth, usually a
bed of rocks or stones. The sewage is trickled over the bed so the
bacteria can break down the organic wastes. The bacteria collect
on the stones through repeated use of the filter.
Upper Sonoran Life Zone—A term categorizing environmental
characteristics found between 3,500 feet and 5,500 feet elevation.
Volatilization—A process whereby a liquid is caused to atomize or
evaporate quickly.
Wildfire—Uncontrolled fire in undeveloped areas such as forests,
brushlands and grasslands.
Wind corridors—Stream valleys descending out of the mountains onto
the plains where valley depressions channel downslope winds. These
channeled winds attain higher velocities than winds found elsewhere
in the area due to Venturi effects resulting from the constricting
stream valley landform.
Window—Linearly planted, closely-spaced trees utilized as a wind
barrier.
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BIBLIOGRAPHY
U.S. EPA Publications
101. U.S. Environmental Protection Agency, Region VIII, Environmental
Carrying Capacity - Case Study of Grand County Area, Colorado,
Denver, October 1976.
102. Environmental Impact Center, Inc., Secondary Impacts of Infra-
structure Investments in the Denver Region, Environmental Pro-
tection Agency; Region VIII, Denver, December 1974.
103. U.S. President's Council on Environmental Quality, Analysis of
Impacts on Prime and Unique Farmland in Environmental Impact
Statements (memorandum), Washington, August 1976.
104. U.S. Environmental Protection Agency Office of Enforcement,
Technical Appendix on Municipal Waste-Source Evaluations in the
South Platte River Basin, Colorado, 1971-72, National Field In-
vestigations Center - Denver and Region VIII, Denver, June 1972.
105. U.S. Environmental Protection Agency Office of Enforcement,
Report on Water Quality Investigations in the South Platte River
Basin, Colorado 1971-72, National Field Investigations Center -
Denver and Region VIII, Denver, June 1972.
106. U.S. Environmental Protection Agency, Region VIII, Denver, Colorado,
Final Environmental Impact Statement for Utah Lake - Jordan River
Water Quality Management Planning Study, Washington, D.C., Septem-
ber 1976.
107. Klotz, David B., Deputy Executive Director, Denver Regional
Council of Governments, letter to Bill Geise, Environmental Pro-
tection Agency; 26 July 1976.
108. Train, Russell E., Administrator, U.S. Environmental Protection
Agency, letter to Honorable Thomas S. Kleppe, Secretary of the
Interior, Washington, D.C., 4 February 1976.
109. Bozich, Frank J., Director, Water Quality Control Division, letter
to John A. Green, Regional Administrator, U.S. Environmental Pro-
tection Agency, 4 May 1976.
110. U.S. Environmental Protection Agency, Proposed Waste Water Treat-
ment Facility, Metro Denver, Colorado, Project Number C 080339,
Denver, May 1975.
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111. Denver Federal Center, Master Plan and Environmental Impact State-
ment, U.S. Environmental Protection Agency, 1976.
112. U.S. Environmental Protection Agency, Region VIII, Review of the
Custer National Forest, Montana's Decision Not to Write An Environ-
mental Impact Statement on a Johns-Manville Corporation Mineral
Prospecting Operation on the West Fork Stillwater River, Montana,
Denver, July 1975.
113. U.S. Environmental Protection Agency, Manual for Preparation of
Environmental Impact Statements for Wastewater Treatment Works,
Facilities Plans, and 208 Areawide Waste Treatment Management
Plans, Washington, D.C., July 1974.
114. Presidential Documents, Title-3, The President, Executive Order
11752, Prevention, Control, and Abatement of Environmental Pollu-
tion at Federal Facilities.
115. U.S. Environmental Protection Agency Office of Federal Activities,
Environmental Impact Assessment Guidelines for Selected New Source
Industries, Washington, D.C., October 1975.
116. Federal Register, Part III: "Environmental Protection Agency;
Preparation of Environmental Impact Statements; Final Regulations,"
Washington, D.C., April 1975.
117. Federal Register, Part VI: "Environmental Protection Agency;
New Source NPDES Permits; Preparation of Environmental Impact
Statements," Washington, D.C., October 1975.
118. Green, John A., U.S. Environmental Protection Agency, letter to
Robert D. Farley, Denver Regional Council of Governments, on
DRCOG's role in the preparation of Denver Metropolitan Wastewater
Facilities Overview EIS, 14 September 1976.
119. Cansecki, Mike, Comments on Metro EIS Procurement Request Ra-
tionale, U.S. Environmental Protection Agency, 14 July 1976.
120. Wilber Smith and Associates, "Financial and Institutional Arrange-
ments for Wastewater Management - Denver SMSA," Environmental Pro-
tection Agency, Region VIII, April 1973.
121. U.S. Environmental Protection Agency, Draft Environmental Impact
Statement, "Proposed Wastewater Treatment Facilities - Southwest
Denver Metropolitan Area," 1974.
122. U.S. Environmental Protection Agency, Region VIII, Denver Regional
Planning Overview, SAI, No. ES76-91, 24 November 1976.
123. U.S. Environmental Protection Agency, Negative Declaration, Metro
Denver Plant Expansion, Project No. C 080339, 19 May 1975.
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124. Cities of Englewood and Littleton, EPA Grant Application and Sup-
porting Documents for Chlorine and Ammonia Toxicity Reduction In-
vestigation, May 1976.
125. U.S. Environmental Protection Agency, RFP, WA 76-B575, Overview
EIS, Scope of Work, Exhibit "A", 3 September 1976.
126. Engineering-Science, Inc., Draft EIS for Metro Denver Sludge Man-
agement Plan, U.S. Environmental Protection Agency, Denver, 1976.
127. U.S. Environmental Protection Agency, Draft Environmental Impact
Statement on Regional Wastewater Facilities Plan, Monterey Penin-
sula Water Pollution Control Agency, 1977.
128. U.S. Environmental Protection Agency, Draft Environmental Impact
Statement (S.W. Metro Water & Sanitation District; City of Engle-
wood; City of Littleton; Cities if Englewood and Littleton), 1974.
129. U.S. EPA Region VII, Control of Reentrained Material From Paved
Streets, PEDCo-Environmental, Inc., March 1977.
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Denver Regional Council of Governments Publications
201. Denver Regional Council of Governments, 208 Basin/Subarea Baseline
Planning Reports - Land Use and Population Data, Denver, November
1975.
202. Denver Regional Council of Governments, "Region's Population
Growth Slows," in COG Notations, Denver, March 1976.
203. Denver Regional Council of Governments, "Population Estimates by
Census Tracts," in COG Notations, Denver, July 1976.
204. Denver Regional Council of Governments, Plan Policies, as adopted
by DRCOG 17 January 1973 and amended June 1974, Denver, 1974.
205. Denver Regional Council of Governments, Land Use Information,
second edition, Denver, July 1972.
206. Denver Regional Council of Governments, EMPIRIC Model Overview
(undated; attribution uncertain).
207. Denver Regional Council of Governments, "Area Population Alloca-
tions Adopted," in COG Notations, Denver, September 1976.
208. Denver Regional Council of Governments, The Changing Region - A
Report on Population Change in the Seventies, Denver, 1976.
209. Denver Regional Council of Governments, Water Quality Management
Program, Volume I - Water Quality Management Report, Denver, May
1974.
210. Denver Regional Council of Governments, Water Quality Management
Program, Volume II - Hydro Quality Model Report, Denver, May 1974.
211. Denver Regional Council of Governments, Water Quality Management
Program, Volume III - Environmental Assessment Report, Denver,
May 1974.
212. Denver Regional Council of Governments, Water Quality Management
Program, Volume IV - Summary of Public Participation, Denver,
May 1974.
213. Denver Regional Council of Governments, Interim Plan for Water
Quality Management in the Denver Metropolitan Area (Storet Code
0910-B), Addendum No. 1, Denver, July 1971.
214. Denver Regional Council of Governments, Interim Plan for Water
Quality Management in the Denver Metropolitan Area, Addendum No. 2,
Denver, October 1972.
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215. Denver Regional Council of Governments, Interim Plan for Water
Quality Management in the Denver Metropolitan Area, Addendum No.
2, Denver, October 1972.
216. Denver Regional Council of Governments, Interim Plan for Water
Quality Management in the Denver Metropolitan Area (Storet Code
No. 0910-B), Denver, April 1974.
217. Denver Regional Council of Governments, Interim Report - Clean
Water Program, Denver, August 1976.
218. Denver Regional Council of Governments, DRCOG Water Quality Man-
agement Program: Volume I, Water Quality Management Report,
Denver, May 1974.
219. Denver Regional Council of Governments, DRCOG Water Quality Man-
agement Program: Volume II - Hydro Quality Model Report, Denver,
May 1974.
220. Denver Regional Council of Governments, DRCOG Water Quality Man-
agement Program: Volume III - Environmental Assessment Report,
Denver, May 1974.
221. Denver Regional Council of Governments, Water Quality Management
in the Denver Metropolitan Area, draft summary-. Denver, January
1974.
222. Denver Regional Council of Governments, Wasteload Allocation Plan,
Denver, February 1974.
223. Denver Regional Council of Governments, Clean Water Program,
Sections I - V, Denver, October 1976.
224. Denver Regional Council of Governments, Clean Water Program,
Sections I - IV, Denver, October 1976.
225. Denver Regional Council of Governments, Clean Water Program,
Vol. II, Denver, October 1976.
226. Denver Regional Council of Governments, Clean Water Program,
Vol. I, Denver, October 1976.
227. Green, John A., Regional Administrator, U.S. Environmental Pro-
tection Agency, letter to David A. Pampu, Assistant Director for
Planning, Denver Regional Council of Governments, Denver.
228. Denver Regional Council of Governments, Clean Water Program,
Denver, October 1976.
229. Denver Regional Council of Governments, Clean Water Program,
Denver, October 1976.
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230. Denver Regional Council of Governments, DRCOG Regional Development
Plan, Policy Population Forecast, Subarea Population Allocation,
August 1976.
231. Denver Regional Council of Governments, Appraisal of the DRCOG
Policy Population Forecast, August 1975.
232. Resource Recovery Management Committee, Resource Recovery from
Solid Waste, A Report to Municipalities and Counties and the
Denver Regional Council of Governments, Denver, July 1976.
233. Denver Regional Council of Governments, "Mountain and Eastern
Plains Water Quality Study," in Water and Related Land Resources
Management Study, Denver, June 1975.
234. Denver Regional Council of Governments, Area Wide Sewerage Master
Plan Report for the Denver Metropolitan Area, Phase I (Inventory),
Denver, March 1970.
235. Denver Regional Council of Governments, Clean Water, A Regional
Approach, August 1976.
236. Denver Regional Council of Governments, Map showing Major Basins,
Sub-basins and Sanitary Sewer Tributary Areas, 1973.
237. Denver Regional Council of Governments, Map showing Existing Sewer
System Deficiencies, 1973.
238. Denver Regional Council of Governments, Map showing Existing Re-
gional Wastewater System, Wastewater Treatment Plants, Major Sewer
Lines, and Combined Sewer System, 1973.
239. Denver Regional Council of Governments, Map showing Regional
Plants; Satellite Plants; Sludge Disposal Sites; New Sewers Re-
quired (1975-1985); New Sewers Required (1985-2000); Limits of
Reachs.
240. Denver Regional Council of Governments, Map showing Wastewater
Service Areas, 1985 Regional Wastewater System, 1973.
241. Denver Regional Council of Governments, Water Quality Management
Planning, Project No. IGA-00034, Table IV-3, Population Projections.
242. Denver Regional Council of Governments, COG Notations, A Report on
Program Activities, Mid-Decade Tabulation, Population Estimates by
Census Tracts.
243. Denver Regional Council of Governments, Evaluation of Water Quality
Implications and Environmental Impacts of Alternative Growth Plans.
208 Study, 9 January 1976.
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244. Geise, J. William, Environmental Protection Agency, letter to
David B. Klotz, Denver Regional Council of Governments, on scope
of work in Denver Metropolitan Area Overview EIS, 27 August 1976.
245. Nolan, James J., Denver Regional Council of Governments, letter to
Rulon R. Garfield, Chairman of Mountain Plains Federal Regional
Council on Regional Environmental Overview Statement of the Denver
Metropolitan Area, 7 September 1976.
246. Denver Regional Council of Governments, Request for Proposal, 1975.
247. Denver Regional Council of Governments, Map showing Parks, Recrea-
tion and Open Space, Revision 1 January 1976.
248. Denver Regional Council of Governments, "Criteria for the Specifi-
cation of Prime Agircultural Lands," Preliminary Draft, November
1976.
249. Denver Regional Council of Governments, "Metro Denver Special
District Directory," Revised 9 August 1976.
250. Denver Regional Council of Governments, "Growth Alternatives for
Re-evaluation of Transportation Needs in the Southwest Metropoli-
tan Area," Colorado Division of Highways, 15 January 1976.
251. Denver Regional Council of Governments, Agenda, Water Resources
Advisory Committee, 19 November 1976.
252. Denver Regional Council of Governments, Comments on Regional
Subarea Population Allocation Study Report.
253. Mugler, Larry, memo re: Current Agricultural Land Use, Task
LU-0.3, Denver Regional Council of Governments, 31 October 1975.
254. Denver Regional Council of Governments, "Area Zoning Could Hold
6.3 Million," in Cognotations, Denver, March 1973.
255. Denver Regional Council of Governments, "Employment Forecast Ex-
pects Growth" in Cognotations, Denver, December 1976.
256. Denver Regional Council of Governments, 208 Land Use and Population
Projections - Regional Alternatives, Denver, 26 February 1976.
257- Denver Regional Council of Governments, EMPIRIC Cycle 4 land
use projections, 5 November 1975.
258. Denver Regional Council of Governments, EMPIRIC Cycle 4, Employ-
ment Projection.
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259. Denver Regional Council of Governments, "Use Potential and Recom-
mended Classifications for the South. Platte River and Tributaries
in the DRCOG 208 Planning Area", Resource Planning Associates, Inc.
Cambridge, Massachusetts, 10 January 1977.
260. Denver Regional Council of Governments, "Sources and Controls of
Non-point Source Pollution", CELM-Hlll, draft, 14 January 1977.
261. Denver Regional Council of Governments, "Wasteland Allocations,
Draft Report", CH M-Hill, Denver, Colorado, 28 January 1977.
262. Denver Regional Council of Governments, "Comments on Stream
Classifications for Specific Areas", undated memo circa, March 1977
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Metropolitan Denver Sewage Disposal District No. 1 Publications
301. Metropolitan Denver Sewage Disposal District No. 1, Advanced Waste-
water Treatment, Denver, March 1974.
302. CH2M Hill, Sequel to Predesign Report - Wastewater Management Lower
South Platte Service Area, Metropolitan Denver Sewage Disposal Dis-
trict No. 1, Denver, June 1974.
303. CH2M Hill, Water Quality - Clear Creek and Sand Creek - Metro
Denver, Denver, June 1974.
304. Environmental Protection Agency, Region VIII, Final Environmental
Impact Statement, Metropolitan Denver Sewage Disposal District
No. 1, Commerce City, Colorado, Denver, February 1974.
305. Environmental Protection Agency, Region VIII, Draft Environmental
Impact Statement, Proposed Wastewater Treatment Facilities, South-
west Denver Metropolitan Area, Denver, 1974.
306. CH2M Hill, Predesign Report, Wastewater Management, Lower South
Platte Service Area for Metropolitan Denver Sewage Disposal District
No. 1, Denver, December 1973.
307. Black & Veatch Consulting Engineers, An Environmental Assessment
of the Proposed Platte River II Interceptor Sewer for Metropolitan
Denver Sewage Disposal District No. 1, Kansas City, Missouri,
July 1974.
308. Metropolitan Denver Sanitation District #1, Commerce City, Colorado.
Project Number C080369, August 1975.
309. Metropolitan Denver Sewage Disposal District No. 1, Commerce City,
Colorado.
310. Metropolitan Denver Sewage Disposal District Nc. 1, Draft, Plan of
Study, Central Plant Facility Plan, November 1976.
311. McNeill, Ray, personal letter re: items 312 through 319, 7 Decem-
ber 1976.
312. Metropolitan Denver Sewage Disposal District No. 1, District Map
with Facilities, revised December 1976.
313. Metropolitan Denver Sewage Disposal District No. 1, District Map,
revised January 1976.
314. Metropolitan Denver Sewage Disposal District No. 1, Platte River
II Interceptor Capacity Chart, computed by R. McNeill.
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315. Denver Metro Engineers, "Predesign Report," Metropolitan Denver
Sewage Disposal District No. 1, August 1961.
316. State of Colorado, "Colorado Revised Statutes Pertaining to Metro-
politan Sewage Disposal Districts," distributed by MDSDD No. 1,
1974.
317. Metropolitan Denver Sewage Disposal District No. 1, "Sewage Treat-
ment and Disposal Agreement (Service Contract)," 1 January 1964.
318. Metropolitan Denver Sewage Disposal District No. 1, "Adapted 1977
Budget," 1 May 1976.
319. Metropolitan Denver Sewage Disposal District No. 1, Map of Members,
Board of Directors, Members of Connectors and Meters, Existing
WWTP's, December 1976.
320. Metropolitan Denver Sewage Disposal District No. 1, Long Range
Plan, September 1976.
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Regional Transportation District, Div. of Highways Publications
401. Colorado Division of Highways, Detailed Assessment Report - 1-470,
Denver, September 1976.
402. Regional Transportation District, A Socio-Economic and Environmental
Assessment of the Colorado Regional Transportation District's Public
Transportation Plan, Vol 2 - Appendix, Draft, Denver, 1973.
403. Regional Transportation District, Environmental Overview: Long
Range Transit Development Analysis, Draft, Denver, April 1975.
404. Regional Transportation District, A Socio-Economic and Environ-
mental Assessment of the Colorado Regional Transportation Dis-
trict 's Public Transportation Plan, Vol. 1 - Technical Report,
Draft, Denver, 1973.
405. Denver Metro Transportation - Air Quality Planning.
406. Joint Regional Planning Program, Public Transportation Plan:
Rapid Transit Facility; Bus Route; Bus Service Area, January 1974.
407. Joint Regional Planning Program, Map showing Highway Plan,
January 1974.
408. Regional Transportation District, Interim Report, December 1971.
409. Regional Transportation District, Arapahoe County Profile, Jan-
uary 1972.
410. Regional Transportation District, Denver County Profile, January
1972.
411. Regional Transportation District, Weld County Profile, January
1972.
412. Regional Transportation District, Interim Report, Phase One -
A Concept, January 1972.
413. Regional Transportation District, Interim Report, Ecology -
Natural Suitabilities for Regional Growth, January 1972.
414. Joint Regional Plnaning Program, Transportation System Report,
Denver, 11 June 1973.
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Facility Plans Publications
501. Denver Water Department, Metropolitan Water Requirements and Re-
sources 1975 - 2010, Vol. I - Text, prepared for the Colorado State
Legislature Metropolitan Denver Water Study Committee, Denver,
January 1975.
502. Denver Water Department, Metropolitan Water Requirements and Re-
sources 1975 - 2010, Vol. II - Primary Study Area Appendix, pre-
pared for the Colorado State Legislature Metropolitan Denver Water
Study Committee, Denver, January 1975.
503. Denver Water Department, Metropolitan Water Requirements and Re-
sources 1975 - 2010, Vol. Ill - Secondary Study Area Appendix, pre-
pared for the Colorado State Legislature Metropolitan Denver Water
Study Committee, Denver, January 1975.
504a. Wastewater Control Division, City and County of Denver, Colorado,
Recommended Improvements to the Northside Wastewater Treatment
Plant, Denver, December 1974.
504b. Wastewater Control Division, City and County of Denver, Colorado,
Recommended Improvements to the Wastewater Collection System,
Denver, December 1974.
505. DMJM/Phillips-Reister, West & Southside Sanitary Main Improvements,
Pre-Design Report II, Denver, February 1975.
506. Henningson, Durham & Richardson of Colorado, Environmental Assess-
ment of the Proposed Littleton-Englewood Regional Waste Water Treat-
ment Plant, Littleton Interceptor Sewer, Englewood Jefferson Drive
Sewer - Denver, December 1973.
507. Henningson, Durham & Richardson of Colorado, Step I EPA Federal
Grant Application and Supporting Documents for the Big Dry Creek
Waste Water Treatment Plant Expansion, February 1976.
508. Henningson, Durham & Richardson of Colorado, Supplemental Step I
EPA Grant Application Supporting Documents for the Big Dry Creek
Waste Water Treatment Plant Expansion, Westminster, Colorado,
May 1976.
509. United States Environmental Protection Agency and Consulting Engi-
neers Sellards & Grigg, Inc., South Adams County Water and Sanita-
tion District, 201 Wastewater Facilities Plan, 1976.
510. CH2M Hill, City of Westminster, Colorado, Infiltration/Inflow
Analysis of the Sewerage Collection System, Corvallis, Oregon,
March 1974.
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511. CH2M Hill, City of Westminster, Colorado, Environmental Assessment
for the Big Dry Creek Wastewater Treatment Plant, Vol. 2, Denver,
January 1975.
512. CH2M Hill, City of Westminster, Colorado, Facility Plan for the
Big Dry Creek Wastewater Treatment Plant, Vol. 1, Denver, January
1975.
513. Treatment and Disposal of Wastewater Sludges, incl. wastewater
facilities design loads for Denver region plants, excerpts from
report, section H.
514. Woodward-Clyde Consultants, Environmental Assessment, EPA - 201
Planning for Glendale, Colorado, Wastewater Treatment Facility,
7 January 1976.
515. City of Westminster, Colorado, Maps of Streets and Facilities.
516. City of Westminster, Colorado, Map of Proposed Facility and Ag
Reuse.
517. City of Thornton, "Storm Drainage and Flood Control Ordinance,"
28 July 1975.
518. CH2M Hill, Inc., Lower South Platte Facility Plan, Phase I Report,
for MDSDD No. 1, September 1976.
519. CH2M Hill, Inc., Clear Creek Facility Plan, Phase I Report, for
MDSDD No. 1, September 1976.
520. CH2M Hill, Inc., Sand Creek Facility Plan, Phase I Report, for
MDSDD No. 1, September 1976.
521. EPA Facilities Plan Study, South Lakewood Sanitation District,
Plan of Study and Preliminary Report, Lakewood, Colorado, 15 Decem-
ber 1976.
522. Applied Science and Resource Planning, Inc., Secondary Effects of
the Proposed Littleton-Englewood Sewer Treatment Plant on the
Southgate Sanitation District, 17 December 1973.
523. Littleton-Englewood Assessment, various figures showing location
of proposed facilities and study region; septic tank areas, service
areas, etc.
524. EPA, Final Environmental Impact Statement for Proposed Wastewater
Treatment Facilities Southwest Denver Metropolitan Area, August
1974.
525. CH2M Hill, Inc., Clear Creek Facility Plan, Phase J Report - Sup-
plement, December 1976.
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526. CH2M Hill, Inc., Sand Creek Facility Plan, Phase I Report - Sup-
plement, December 1976.
527. CH2M Hill, Inc., Lower South Platte Facility Plan, Phase I Report
Supplement, for MDSDD No. 1, December 1976.
528. MDSDD No. 1, Plan of Study - Central Plant Facility Plan, 7 Jan-
uary 1977.
529. Black & Veatch, State Funding Priority List for Facility Plans,
Problem Areas of Metro Facility Plans, Regional Environmental -
Administrative Issues Facing Metro Area Facility Plans, Decision
Options on Environmental Issues.
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U.S. Department of the Interior Publications
601. U.S. Department of the Interior, Land Use Classification of the
Greater Denver Area, Front Range Urban Corridor, Colorado, Reston,
Virginia, 1975.
602. U.S. Department of the Interior, Upper South Platte Unit, Mount
Evans Division, Pick-Sloan Missouri Basin Program, Colorado,
Multiobjective Planning of Water and Related Land Resources, Field
Draft Feasibility Report, Denver, October 1974.
603. U.S. Department of the Interior, Bureau of Land Management, Draft
Environmental Impact Statement, Proposed Foothills Project.
604. U.S. Department of the Interior, "Geological Survey," Map of Flood
Prone Areas, 1973.
605. U.S. Department of the Interior, Map showing Potential Gravel
Sources and Crushed-Rock Aggregate in the Greater Denver Area,
Front Range Urban Corridor, Colorado.
606. U.S. Department of the Interior, map showing Potential Soruces of
Gravel and Crushed Rock Aggregate, in the Boulder-Fort Collins-
Greeley Area, Front Range Urban Corridor, Colorado.
607. U.S. Department of the Interior, U.S.G.S. map showing Mined Areas
of the Boulder-Weld Coal Field, Colorado, 1973.
608. U.S. Department of the Interior, U.S.G.S. Land Use Classification
map of the Boulder-Fort Collins-Greeley Area, Front Range Urban
Corridor, Colorado.
609. U.S. Department of the Interior, U.S.G.S. map showing Outstanding
Natural and Historic Landmarks in the Greater Denver Area, Front
Range Urban Corridor, Colorado.
610. U.S. Department of the Interior, U.S.G.S. map showing Availability
of Hydrologic Data Published by the U.S. Environmental Data Service
and by the U.S.G.S. and Cooperating Agencies Greater Denver Area,
Front Range Urban Corridor, Colorado.
611. U.S.G.S. Geologic Map of the Arvada Quadrangle, Adams, Denver and
Jefferson Counties, Colorado.
612. U.S.G.S., Lakes in the Greater Denver Area Map, Front Range Urban
Corridor, Colorado.
613. U.S. Department of the Interior, Bureau of Land Management, Water
for Tomorrow, Phase I - Appraisal Report, Colorado State Water
Plan, February 1974.
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614. U.S. Department of the Interior, Fish and Wildlife Service, "State
Lists of Endangered and Threatened Species of the Continental
United States," Federal Register, Vol. 40, No. 127, 1 July 1975.
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U.S. Department of Agriculture Publications
701. U.S. Department of Agriculture Soil Conservation Service (in
cooperation with Colorado Agricultural Experiment Station), Soil
Survey Arapahoe County, Colorado, U.S. Government Printing Office,
Washington, D.C., March 1971.
702. U.S. Department of Agriculture Soil Conservation Service (in co-
operation with Colorado Agricultural Experiment Station), Soil
Survey of Adams County, Colorado, Washington, D.C., October 1974.
703. Colorado Department of Agriculture, Colorado Agricultural Sta-
tistics, 1975 Preliminary, 1974 Final, Denver, July 1976.
704. Colorado Department of Agriculture, Colorado Agricultural Sta-
tistics, Bulletin 1-75, Denver, July 1975.
705. Environmental Resources Center, Colorado State University, Com-
pletion Report No. 75, Physical and Economic Effects on the Local
Agricultural Economy of Water Transfer to Cities, October 1976.
706. U.S. Department of Agriculture Soil Conservation Service (in co-
operation with Colorado Agricultural Experiment Station), Soil
Survey Boulder County Area, Colorado, U.S. Government Printing
Office, Washington, D.C., January 1975.
707. Davis, R. M., U.S. Department of Agriculture Soil Conservation
Service, "Land Inventory and Monitoring Memorandum - 3," re:
Prime and Unique Farmlands, 15 October 1975.
708. U.S. Department of Agriculture Soil Conservation Service (in co-
operation with Colorado Agricultural Experiment Station), Soil
Survey, Castle Rock Area, Colorado, U.S. Government Printing
Office, Washington, D.C., November 1974.
709. U.S. Department of Agriculture Soil Conservation Service, map
showing "Land Use, Boulder County, Colorado," July 1973.
710. U.S. Department of Agriculture Soil Conservation Service, "General
Soil Map, Boulder County," May 1972.
711. U.S. Department of Agriculture Soil Conservation Service, "General
Soil Map, Jefferson County," June 1972.
712. U.S. Department of Agriculture Soil Conservation Service, "General
Soil Map, Elbert County," July 1972.
713. U.S. Department of Agriculture Soil Conservation Service, "General
Soil Map, Douglas County," June 1972.
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714. U.S. Department of Agriculture Soil Conservation Service, "General
Soil Map, Arapahoe County," March 1972.
715. U.S. Department of Agriculture Soil Conservation Service, "General
Soil Map, Adams County," April 1972.
716. U.S. Department of Agriculture Soil Conservation Service, land
use map of Douglas County, August 1973.
717. Colorado Department of Agriculture, Colorado Agricultural Sta-
tistics, 1974 Preliminary, 1973 Final, Denver, July 1975.
718. Carey, Merritt, "A Biological Survey of Colorado," U.S.D.A.
Bureau of Biological Survey - North American Fauna #33, 1911.
719. U.S. Department of Agriculture, Economic Research Service, Dy-
namics of Land Use in Fast Growth Areas, 1976.
720. U.S. Department of Agriculture, Economic Research Service, Our
Land and Water Resources - Current and Prospective Supplies of
Uses, 1974.
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U.S. Geological Survey Publications
801. Department of the Interior, U.S. Geological Survey, Map Showing
Availability of Hydrologic Data, Boulder - Fort Collins - Greeley
Area, Front Range Urban Corridor,- Colorado, Reston, Virginia, 1974
802. Department of the Interior, U.S. Geological Survey, Map Showing
Flood-prone Areas, Boulder - Fort Collins - Greeley Area, Front
Range Urban Corridor, Colorado, Reston, Virginia, 1975.
803. Department of the Interior, U.S. Geological Survey, Land-Use
Classification of the Greater Denver Area, Front Range Urban
Corridor, Colorado, Reston, Virginia, 1975.
804.
805. Department of the Interior, U.S. Geological Survey, Map Showing
Availability of Hydrologic Data Published by the U.S. Environ-
mental Data Service and by the U.S. Geological Survey and Cooper-
ating Agencies, Greater Denver Area, Front Range Urban Corridor,
Colorado, Reston, Virginia, 1975.
806. Department of the Interior, U.S. Geological Survey, Map Showing
Potential Gravel Sources and Crushed-rock Aggregate in the Greater
Denver Area, Front RAnge Urban Corridor, Colorado, Reston, Vir-
ginia, 1974.
807. Department of the Interior, U.S. Geological Survey, Maps Showing
the Approximate Configuration and Depth to the Top of the Laramie-
Fox Hills Aquifer, Denver Basin, Colorado, Washington, D.C., 1972.
808. Department of the Interior, U.S. Geological Survey, Generalized
Surficial Geologic Map of the Denver Area, Colorado, Washington,
D.C., 1972.
809. Department of the Interior, U.S. Geological Survey, Map Showing
Outstanding Natural and Historic Landmarks in the Greater Denver
Area, Front RAnge Urban Corridor, Colorado, Reston, Virginia, 1976.
810. Department of the Interior, U.S. Geological Survey, Land-Use
Classification Map of the Boulder - Fort Collins - Greeley Area,
Front Range Urban Corridor, Colorado, Reston, Virginia, 1974.
811. Department of the Interior, U.S. Geological Survey, Map Showing
Potential Sources of Gravel and Crushed-rock Aggregate in the
Boulder - Fort Collins - Greeley Area, Front Range Urban Corridor,
Colorado, Reston, Virginia, 1974.
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812. U.S. Geological Survey, Map Showing Mined Areas of the Boulder -
Weld Coal Field, Colorado, U.S. Government Printing Office, 1974.
813. Department of the Interior, U.S. Geological Survey, Geologic Map
of the Arvada Quadrangle, Adams, Denver, and Jefferson Counties,
Colorado, 1972.
814. U.S. Geological Survey, "Effect of Mine Drainage on the Quality
of Streams in Colorado, 1971-72," Colorado Water Pollution Con-
trol Commission, Circular No. 21, 1974.
815. U.S. Geological Survey, "Effects of Metal-Mine Drainage on Water
Quality in Selected Areas of Colorado, 1972-73," Colorado Water
Pollution Control Commission, Circular No. 25, 1974.
816. Colorado Water Conservation Board, U.S. Geological Survey map
showing "Index of Flood Plain Information in Colorado, January
1975."
817. U.S. Geological Survey, Lakes in the Greater Denver Area, Front
Range Urban Corridor,- Colorado, 1975.
818. U.S. Geological Survey, Map Showing Flood-Prone Areas, Greater
Denver Area, Front Range Urban Corridor, Colorado, Reston, Vir-
ginia, 1975.
819. Smith, Rex 0., Paul A. Schneider, Jrl, and Lester R. Petri,
"Ground Water Resources of the South Platte River Basin in West-
ern Adams and Southwest Weld Counties, Colorado", U.S. Geological
Survey - Water Supply Paper 1658, 1964.
820. Price, Don and Ted Arnow, "Summary Appraisals of the Nation's
Ground-Water Resources - Upper Colorado Region", U.S. Geological
Survey Professional Paper 813-C, 1974.
821. McConaghy, J. A. et_ al_. , "Hydrogeologic Data of the Denver Basin,
Colorado", U.S. Geological Survey, Denver, 1964.
-------
Miscellaneous Publications
901. Engineering Consultants, Inc. (ECE) and the Toups Corporation,
Proposal for the Study of Land Treatment and Water Rights for
Denver Metro Area, Denver, May 1974.
902. Heiss, F. W. , Denver Metropolitan Study, Research and Action Plan
1976-1977.
903. Platte River Development Committee, South Platte River Development,
Project Description and Budget; Maps; Newspaper Articles.
904. Denver Urban Observatory, Denver Urban Observatory Five-Year
Report, 1970-1975, Denver, 1976.
905. Denver Urban Observatory, The Economic Base of Denver: Implications
for Denver's Fiscal Future and Administrative Policy, Boulder, 1974.
906. U.S. Department of Housing and Urban Development, Proposal for
Denver Metropolitan Environmental Analysis, Washington, 1976.
907. Resource Planning Associates, Inc., 208 Technical Memorandum 302,
Development Criteria to Keep Impact Within Acceptable Levels,
Cambridge, Massachusetts, 19 March 1976.
908. Benedict, H. M., C. J. Miller, and J. S. Smith, Stanford Research
Institute, "Assessment of Economic Impact of Air Pollutents on
Vegetation in the United States: 1969 and 1971", prepared for
coordinating Research Council and EPA, July 1973.
909. Millecan A. A., California State Department of Food and Agriculture,
"A Survey and Assessment of Air Pollution Damage to California
Vegetation 1970 through 1974, April 1976.
910. Resource Planning Associates, Inc., Technical Memorandum 4-1,
Water Quality Analysis of the Local and Regional Forecasts,
(undated, attribution uncertain.)
911. Resource Planning Associates, Inc., 208 Technical Memorandum 6-1,
Detailed Environmental Impact Evaluation Plan, Cambridge, Mass.,
January 1976.
912. Resource Planning Associates, Inc., 208 Task 6-2, Evaluate Basin
Environmental Impacts - Cherry Creek Basin, Preliminary Discussion
Draft, Cambridge, Mass., February 1976.
913. National Academy of Public Administration, Denver Metropolitan
Study, Research and Action Plan, 1976-1977, Denver, 1976.
914. Monarchi, David E. and Ken D. Prince, "Forecasting with the CPE
Model - Some Practical Experiences", Colorado Population Trends,
Vol. 4, No. 4, Boulder, Fall 1975.
-------
915. Business Research Division, University of Colorado, "County Popula-
tion Projections - 1970 - 2000", Colorado Population Trends, Vol.
5, No. 1, Boulder, Winter 1976.
916. CH2M Hill and Leonard Rice Consulting Water Engineers, Inc.,
Task Memorandum 6-4, D09523F0.40, Technical Impacts of First
Round Alternatives, Denver, 30 July 1976.
917. CH2M Hill and Leonard Rice Consulting Water Engineers, Inc.,
Task Memorandum 6-3, D09523F0.30, First Round Alternatives,
Denver, 30 July 1976.
918. The Research Group, Inc., A Report to the Denver Regional Council
of Governments Assessing Areawide Water pollution Management Is-
sues, Attitudes of Public Officials, and Alternative Approaches to
Water Quality Planning and Management for Implementation of the
Denver Regional Clean Water Program, Atlanta, April 1976.
919. The Research Group, Inc., 208 Institutional Memorandum-1, An
Assessment of Existing Water Quality Management Goals, and the
Development of Suggested Regional Water Quality Goals for the
DRCOG, Atlanta, June 1976 (with August 1976 corrections) .
920. The Research Group, Inc., 208 Institutional Memorandum-2, .Re-
porting on: (1) Areawide Water Pollution Management Issues,
Attitudes of Public Officials and Alternative Approaches to Water
Quality Planning and Management for Implementation of the Denver
Regional Clean Water Program; (2) Preparation for and Participation
in the Institutional Workshop at the Botanic Gardens on April 22,
1976; and (3) Analysis of the Output from the Institutional Work-
shop, Atlanta, June 1976.
921. The Research Group, Inc., 208 Institutional Memorandum-3, Reporting
on: (1) The Existing Institutional System for Dealing with Water
Quality Management in the Denver Region; (2) Alternative Institu-
tional Systems for Dealing with Future Management Programs and
Issues; and (3) A System for Evaluating the Institutional Alter-
natives, Atlants, June 1976 (with August 1976 corrections).
922. Colorado Division of Planning, The Division of Planning: A Profile,
Information Services Report Number 1, Denver, April 1976.
923. Colorado Division of Planning, Colorado's Regions, Information
Services Report Number 2, Denver, April 1976.
924. Taylor, G. C., Water Demand Projections, Project 5152, Chapter VI,
28 July 1975.
925. Denver Metropolitan Study, The Denver Region Citizen-Voter: RE-
ported Ideas and Concerns, September 1976.
-------
926. Weston, Warren et al., Voter Attitudes in Denver, Denver Urban
Observatory, 1976.
927- Cristiano, C. R., Kater Conservation Measures, Project 5152,
Chapter VIII, 30 June 1975.
928. Denver Urban Observatory, Publications list, 13 September 1976.
929. Milliken, J. Gordon (DRI) , Demonstrate. ?r: cf tr.e F,va.lvdtit;ri/I)ecision
Process, first draft, Chapter XXI, 13 July i975.
930. Three newspaper articles, unspecified sources.
931. Peterson, Russell W. (CEQ), Memorandum for heads of agencies:
Analysis of Impacts on Prime and Unique Farmland in Environmental
Impact Statements, 30 August 1976.
931a. Objectives of Metro EIS.
932. Description of Denver facilities being planned.
933. Thompson, C. R. , G. Kats, and J. W. Cameron, "Effects of Ambient
Photochemical Air Pollutents on Growth, Yield, and Ear Characters
of Two Sweet Corn Hybrids", Journal of Environmental Quality,
Volume 5 No. 4, October-December 1976.
934. Socio Economic Systems, Inc., Service Area Population Projections
for the Boulder EIS, personal communication, letter to EPA,
9 November 1976.
935. Leonard Rice Consulting Engineers, Inc., "Water Engineering in
Colorado", January 1975.
936. Colorado Department of Health, Water Quality Control Commission,
"Proposed Water Quality Standards for Colorado", 28 October 1976.
937. Suhrbier, John H., Cambridge Systematics, Inc., letter to Robert
Kessler, U.S. Department of Transportation, re: "DOT Office of
Environmental Affairs Contract, 'Costs and Administrative Support
for Implementation of Air Quality Transportation Controls'.",
18 October 1976.
938. Suhrbrier, John H., Cambridge Systematics, Inc., letter to Robert
D. Siek, Colorado Department of Health, re: DOT/EPA study in
Denver, 18 October 1976.
939. Engineering-Science, Inc., An Engineering Study for Water Control
and Recycle, as presented to the U.S. Atomic Energy Commission,
Rocky Flats Plant, Golden, Colorado, 21 July 1974.
940. Inter-County Regional Planning Commission, Metropolitan Water Study
Inventory Map showing "Divisions, Storage and Sewage Plant Loca-
tions", 1965.
-------
941. State of Colorado, Department of Natural Resources, Division of
Wildlife, "Colorado Breeding Data for Select Bird Species",
Second Revision, May 1976.
942. State of Colorado, Department of Natural Resources, Division of
Wildlife, The Strategy of Today, For Wildlife Tomorrow, Vol. 1,
1975 - 1980, 1974.
943. Leonard Rice Consulting Water Engineers, Inc., Botham, Leslie H. ,
memo re: "Status of Flood Hazard Area Mapping in Colorado",
16 December 1976.
944. Botham, L. H., Leonard Rice Consulting Water Engineers, Inc.,
"Status of FIA Studies", 14 December 1976.
945. Colorado Water Conservation Board, "Status of Flood Hazard Area
Designations".
946. Commerce City, "Environmental Assessment, Dahlia Street Bridge",
May 1975.
947. Leonard Rice Consulting Water Engineers, Inc., Wood Brothers
Homes Water Rights Evaluation, 27 July 1973.
948. Ingraham, E. W., "Lead Time for Assessing Land Use: A Case Study",
Science, 194, p. 17, 1 October 1976.
949. Department of Operational Services, Plants Division, 1975 Annual
Report, City of Westminster, Colorado.
950. Northglenn Policy Statement on Cooperative Use of Land and Water
Resources.
951. Uranesh, G., et al., Colorado Water Law and Clean Water by Irriga-
tion with Sewage Effluent.
952. Colorado Air Pollution Control Regulations.
953. Johnston, W. W., memo re: "Basin/Subbasin Population Allocations
for HSP Modeling", to J. Hibbert, WRS, 1 September 1976.
954. Anderson, Gerald A., Systems Applications, Inc., (SAI), Report on
Status of Photochemical Modeling, SAI Report No. ES76-92 prepared
for EPA, 22 November 1976.
955. Systems Applications, Inc., A Study of the Effect of Changes in the
Spatial Distribution of Emissions, SAI Report NO. ES76-92 prepared
for EPA, 22 November 1976.
-------
956. See Reference 114.
957. Gruen + Gruen Associates, Bibliography of Denver EIS.
958. CH2M Hill and Leonard Rice Consulting Water Engineers, Inc., Task
Memorandum 3-1, 3-2, 3-3, 4-la through 4-lf, 4-2a through 4-2e,
5-1, 5-3, 5-5, 6-1 thorugh 6-4, 7-3, 8-1 through 8-6; Institutional
Memorandum 1, 2, and 3; Public Involvement Memorandum 1 and 2,
Financial Memorandum 1-1, 1-2, and 3; Technical Memorandum 2-5.
3-2, 4-1, 6-1, 2-3, 4-3, and 5.
959. CH2M Hill and Leonard Rice Consulting Water Engineers, Inc., 208
Program Profile, Point Sources, Urban Runoff., and Agricultural
Irrigation Return Flow, August 1976.
960. Boulder County, "Ponding Ordinances", in Subdivision Regulations.
961. City of Arvada, Engineering Department, "Basin Ordinances", in
Standard Specifications & Drawings for Design & Construction.
962a. Colorado Energy Research Institute, Summary Report, January 1976.
962b. Colorado Energy Research Institute, Future Energy Alternatives
for Colorado, Vol. I, January 1976.
963. Urban Drainage and Flood Control District, Activity Summary,
March 1976.
964. Resource Planning Associates, Summary of Interview Findings,
Fishery Potential for Denver Regional Streams, 10 December 1976.
965. Colorado Land Use Commission, Colorado Land Use Map Folio,
January 1974.
966. Krus, John, South Lakewood Sanitation District, personal communi-
cation, 8 February 1977.
967. Dravde, Alwin, Bookkeeper, South Lakewood Sanitation District,
personal communication, 8 February 1977.
968. Colorado Legislature S.B. 142, "Nongame and Endangered Species
Conservation Act," 1973.
969. Tully, R. J., "Endangered Wildlife", in Colorado Outdoors, Colo-
rado Division of Wildlife, March-April 1973.
970. Colorado Energy Research Institute, Future Energy Alternatives
for Colorado, January 1976.
971. Jenkins, David, "Ugly Scars Mar Nature Preserve", in The Denver
Post, p. 33, 25 November 1976.
-------
972. Signs, Cheryl, Water Resource Engineer, City of Westminster,
personal communication, 22 February 1977.
973. Schwochow, S. D. , R. R. Shroba, and P. C. Wicklein, "Sand, gravel
and Quarry Aggregate Resources, Colorado Front Range Counties",
in Colorado Geological Survey, Department of Natural Resources,
Denver, 1974.
974. Pearl, Richard Howard, "Geology of Ground Water Resources in
Colorado", in Colorado Geological Survey, Department of Natural
Resources, Denver, 1974.
975. Adams, W. and Ed Mansfield, "Engineering Geology Case Histories
No. 8, Engineering Seismology: The Works of Man", prepared for
the Division on Engineering Geology of the Geological Society of
America, Boulder, 1970.
976. McCall, Ellingson, & Merrill, Inc., City of Longmont - Sewage
Facilities Report, prepared for EPA, February 1975.
977. Pankratz, Howard, "Reward is Bankruptcy: Agribusiness Problems
Grow", in The Denver Post, p. 21, 27 February 1977-
978. Lundahl, Richard P., Project Director of Land and Water Resources
Management, City of Northglenn, personal communication, letter of
10 February 1977.
979. U.S. Department of Health, Education and Welfare, Air Quality
Criteria for Photochemical Oxidants, March 1970.
980. U.S. Department of Health, Education and Welfare, Air Quality
Criteria for Carbon Monoxide, March 1970.
981. U.S. Department of Health, Education and Welfare, Air Quality
Criteria Document, January 1969.
982. Hendricks,- D. W. and M. H. Bluestein, "Response of South Platte to
Effluent Limitations", in Journal of the Environmental Engineering
Division, ASCE, Vol. 102, August 1976.
983. Brown, Lester R., "The Urban Prospect: Reexamining the Basic
Assumption" in Environmental Comment, Washington, D.C., December
1976.
984. Colorado, State of, Department of Agriculture, Colorado Crop
Census, 1976.
985. Colorado, State of, Division of Planning, "County Population Pro-
jections - 1970 to 2000" in Colorado Population Trends, Winter 1976.
-------
986. Colorado State University, Environmental Resources Center, Physical
and Economic Effects on the Local Agricultural Economy of Water
Transfer to Cities, October 1976.
987. Denver Urban Observatory, The Economic Base of Denver: Implica-
tions for Denver's Fiscal Future and Administrative Policy, Denver,
1974.
988. Farm and Land Realtor, September 1976.
989. Gruen Gruen 4- Associates and Sedway/Cooke, Approaches Towards a
Land Use Allocation System for California's Coastal Zone - A
Report to the Resources Agency, State of California, October 1971.
990. Hoyt, Homer, The Changing Principles of Land Economics, Urban Land
Institute, Washington, D.C., 1968.
991. Security Pacific Bank, Monthly Summary of Business Conditions,
September 1976.
992. Snyder, Robert W., Agricultural Land Use Policy: Some Perspectives
and Observations, University of Minnesota, Agricultural Extension
Service, 1976.
993. Systems Applications, Inc., Denver Regional Planning Overview
(Preliminary Draft), prepared for the EPA, 24 November 1976.
994. U.S. Department of Commerce, Bureau of the Census, 1970 Census of
Population: State Economic Areas, Washington, D.C., 1970.
995. U.S. Department of Commerce, Bureau of the Census, 1970 Census of
Population: General Social and Economic Characteristics (U.S.
Summary), Washington, D.C., 1970.
996. U.S. Department of Commerce, Bureau of Economic Analysis, Survey
of Current Business.
997. Jones, S., "Public Response to Air Pollution in the Denver Area"
University of Colorado Environmental Council, pp. 21-52, 1974.
998. Anderson, G. E., etal, A Study of Air Quality in the Denver Met-
ropolitan Region (1974-2000), Systems Applications Incorporated
report No. ES77-222 for US EPA Region VIII, May 1977.
-------
Local Agency Plans and Planning Documents
1000. Alonso, William, "The Economics of Urban Size" in Papers of the
Regional Science Association, European Congress, London, England,
p. 67-83, 1970.
1001.
1002.
1003. Adams County Department of Planning and Development, Adams
County Comprehensive Plan, Brighton, Colorado, 1975.
1004. Arapahoe County Planning Department, Urban Area, Arapahoe County
Comprehensive Plan, Littleton, Colorado, November 1972 including
amendments through September 1976.
1005. Arvada Planning Commission, The Comprehensive Plan for the City
of Arvada, Arvada, Colorado, October 1973.
1006. Aurora Department of Planning and Community Development, Aurora/
The People Within - A Demographic Study, Aurora, Colorado, October
1975.
1007. Aurora Department of Planning and Community Development, Prelimi-
nary Revised Population Projections 1975-2000, Aurora, Colorado,
September 1975.
1008. Aurora Department of Planning and Community Development, Long Range
Planning Division, Growth in Aurora, Population and Vacancy Summary,
Aurora, Colorado, July 1976.
1009. Aurora Planning Department, A Report on Economic Analysis of the
City of Aurora, Aurora, Colorado, November 1973.
1010. Aurora Planning Department, A Report on Population Growth in the
City of Aurora, Aurora, Colorado, March 1973.
1011. Aurora Planning Department, The Land Use Plan for the City of
Aurora, Aurora, Colorado, June 1974.
1012. Boulder Department of Community Development, Boulder Valley Compre-
hensive Plan, Boulder, Colorado, 1970.
-------
1113. Broomfield, Comprehensive Master Plan - City of Broomfield (by
CNC/NHPQ), Broomfield, Colorado, August 1972 including amendments
through August 1973.
1014. Commerce City Planning Staff and Citizens' Review Committee, Land
Use Plan 1975-2000 - Second Draft, Commerce City, Colorado, June
1976.
1015. Commerce City Planning Staff, Existing Land Use Map, Commerce
City, Colorado, June 1976.
1016. Denver Planning Office, Denver 1985 - A Comprehensive Plan for Com-
munity Excellence, Denver, Colorado, January 1971.
1017. Denver Planning Office, Neighborhood Planning, Denver, Colorado,
1976.
1018. Denver Planning Office, Preliminary Comprehensive Planning Goals
and Objectives for Denver - A Report for Information and Discussion,
Denver, Colorado, September 1976.
1019. Denver Planning Office, Trends and Issues - Land Use and Physical
Development in Denver - A Report for Information and Discussion,
Denver, Colorado, January 1976.
1020. Denver Planning Office, Planning Services Division, 1975 Census of
Bousing and Land Use, Denver, Colorado, July 1975.
1021. Denver Planning Office, Planning Services Division, 1976 Population
Estimate, Denver, Colorado, June 1976.
1022. Douglas County Planning Department, Land Use Plan for Douglas
County, Colorado, Castle Rock, Colorado, 1974.
1023. Edgewater, Comprehensive Plan (by Small, Cooley and Associates),
Denver, Colorado, 1967.
1024. Englewood, A Place to Live, Englewood, Colorado, January 1970.
-------
1025. Englewood, Population and Land Use, Englewood, Colorado, January
1970.
1026. Federal Heights, Federal Heights Zoning Information Map J^r^
Heights, Colorado, February 1966 including revisions through
November 1973.
1027. Golden, A Comprehensive Plan for Golden, Colorado (by Havekost/
Waldman & Associates), Denver, Colorado, April 1971.
1028. Golden, Draft Land Use and Housing Component of Comprehensive Plan,
Golden, Colorado, 1976.
1029. Greenwood, Greenwood Village Master Plan (by Carl A. Worthington &
Associates), Boulder, Colorado, February 1973.
1030. Jefferson County Planning Department, JJ Comprehensive Plan Policies,
(under consideration for adoption), Golden, Colorado.
1031. Jefferson County Planning Department, Future Land Use Map, Golden/
Ralston Community, Golden, Colorado, September 1974.
1032. Jefferson County Planning Department, Future Land Use Map, Mountain
Area, Jefferson County, Colorado, Golden, Colorado, 1971.
1033. Jefferson County Planning Department, Future Land Use Map, Northeast
Jefferson County Area, Golden, Colorado, July 1971.
1034. Jefferson County Planning Department, Advanced Planning Section,
The Golden-Ralston Comprehensive Plan, Golden, Colorado, 1974.
1035. Lakewood Department of Community Development, Concept Lakewood: A
Development Plan and Planning Process, Lakewood, Colorado, March 1975.
1036. Northglenn Department of Community Development, City of Northglenn
Zoning District Map, Northglenn, Colorado, January 1973 including
amendments through 25 October 1976.
-------
1037. Sheridan, Management Study for the City of Sheridan, (by Parker &
Associates, Inc.), Denver, Colorado, 15 January 1974.
1038. Sheridan, Official Zoning Map - City of Sheridan, Colorado, (by
Parker & Associates, Inc.), Denver, Colorado, June 1972 including
revisions of January 1975.
1039. Thornton, Thornton: A Comprehensive Plan, Thornton, Colorado, March
1975.
1040. Thornton, City of Thornton Economic Base Analysis (by Harmon,
O'Donnell & Henninger Associates, Inc.), Denver, Colorado, 10 May
1974.
1041. Westminster City Council, Ordinance Number 959, Series of 1976,
Westminster, Colorado, June 1976.
1042. Westminster Planning Department, Annexation Criteria, Westminster,
Colorado.
1043. Westminster, Comprehensive Plan - City of Westminster (by Small,
Cooley and Associates), Westminster, Colorado, 1973.
1044. Stromberg and Davidson, personal communication, December 1976.
1045. Zwagerman, personal communication, 12 January 1977.
1046. Fleming, R., Planning Director, Adams Co., personal communication,
13 January 1977.
-------
DISTRIBUTION LIST
Federal Agencies
Regional Forester
U.S. Forest Service
Denver, Colorado
Federal Highway Administration
Denver, Colorado
State Conservationist
U.S. Soil Conservation Service
Denver, Colorado
Regional Director
U.S. Department of Health,
Education and Welfare
Denver, Colorado
Corps of Engineers
Omaha District
Omaha, Nebraska
Regional Administrator
U.S. Department of Housing
and Urban Development
Denver, Colorado
Director (18)1
Environment Project Review
U.S. Department of the Interior
Office of the Secretary
Washington, D.C.
State Director
Farmers Home Administration
U.S. Department of Agriculture
Denver, Colorado
Mr. Jerry Steck
General Services Administration
Denver, Colorado
Council on Environmental Quality (5)2
Washington, D.C.
State Agencies
State Clearinghouse (15)3
Office of State Planning
Denver, Colorado
Air Pollution Control Division
Colorado Department of Health
Denver, Colorado
Water Quality Control Division
Colorado Department of Health
Denver, Colorado
Mr. Jim Monahan
Governor's Office
County Agencies
Division of Planning
Denver County
Department of Health
Adams County
Division of Planning
Boulder County
Division of Planning
Jefferson County
Division of Planning
Douglas County
Division of Planning
Arapahoe County
1 18 copies provided for Department of the Interior offices
2 5 copies provided for Council on Environmental Quality
3 15 copies provided to State Clearinghouse for review by state agencies
-------
Local Agencies
Planning Director
City of Arvada
Planning Director
City of Aurora
Planning Director
City of Boulder
Planning Director
City of Broomfield
Planning Director
City of Cherry Hills Village
Planning Director
City of Commerce City
Planning Director
City of Denver
Chairman, Planning Commission
City of Edgewater
Director of Community Development
City of Englewood
Chairman, Planning Commission
City of Federal Heights
Public Works Department
City of Broomfield
Planning Director
City of Glendale
Assistant City Manager/Planner
City of Golden
Planning Director
City of Greenwood Village
Planning Director
City of Lakewood
Planning Director
City of Littleton
Planning Director
City of Northglenn
Planning Director
City of Sheridan
Planning Director
City of Thornton
Planning Director
City of Westminster
Planning Director
City of Wheat Ridge
Housing Authority of Denver
Denver, Colorado
Denver Urban Renewal Authority
Denver, Colorado
Parks and Recreation Department
Denver, Colorado
Board of Water Commissioners
Denver, Colorado
Grant Applicants
Mr. Andy McGown
City Manager
City of Englewood
Mr. Wayne T. Ward
President, Board of Directors
South Lakewood Sanitation District
Mr. Gale D. Christy
City Manager
City of Littleton
Honorable William H. McNichols, Or.
Mayor, City and County of Denver
Mr. Allen L. Williams
Chairman, Board of Directors
South Adams County Water and
and Sanitation District
-------
Grant Applicants (continued)
Mr. William E. Korbitz
Manager
Metropolitan Denver Sewage
Disposal District #1
Mr. Steve Garman
City Manager
City of Westminster
EIS Advisory Committee
Mr. David Klotz (5)1
Denver Regional Council
of Governments
Mr. Leonard Slosky
Colorado Department of Highways
Mr. Kenneth W. Webb
Colorado Water Quality Control Division
Mr. Gary Broetzman
State 208 Coordinator
Governor's Office
Mr. Warner Reeser
Colorado Air Pollution Control Division
Ms. Toni Worcester
League of Women Voters of
Metro Denver
Mr. Larry Smith
Federal Highway Administration
Colorado Division Office
Mr. Walter Kelm
U.S. Department of Housing
and Urban Development
Denver, Colorado
Mr. Ken Slyziuk
Regional Transportation District
Denver, Colorado
Mr. Bob Moore
Attn: Mr. Dave Taliafero
Bureau of Land Management
Denver, Colorado
Local Elected Officials
James Covey, Chairman
Adams County Commissioners
John J. Nicholl, Chairman
Arapahoe County Commissioners
Margaret B. Markey, Chairwoman
Boulder County Commissioners
Harold V. Cook
Deputy Mayor and Chairman,
County Commissioners
Joanne Paterson, Chairman
Jefferson County Commissioners
Donald L. Feland
Mayor, City of Arvada
Fred Hood
Mayor, City of Aurora
Frank Buchanan
Mayor, City of Boulder
William Thornton
Mayor, Town of Bow Mar
Guy R. Sanders
Mayor, City of Brighton
Walter P. Spader
Mayor, City of Broomfield
Beth Jenkins
Mayor, Cherry Hills Village
1 5 copies provided to Denver Regional Council of Governments
-------
Local Elected Officials (continued)
Allen L. Williams
Mayor, City of Commerce City
Don Wise
Mayor, City of Edgewater
James L. Taylor
Mayor, City of Englewood
Lester M. Bauer
Mayor, Town of Federal Heights
George Garson
Mayor, City of Glendale
David Crawford
Mayor, City of Golden
Harold Patton, Jr.
Mayor, Greenwood Village
James J. Richey
Mayor, City of Lakewood
Harold Meyer
Mayor, City of Littleton
Gail Molinaro
Mayor, Town of Morrison
Alvin B. Thomas
Mayor, City of Northglenn
Wilfred D. Corbin
Mayor, City of Sheridan
Anthony E. Richter
Mayor, City of Thornton
Vi June
Mayor, City of Westminster
Frank Stites
Mayor, City of Wheat Ridge
John G. Campbell
County Commissioner
Brighton, Colorado
Charles A. Pitts
County Commissioner
Littleton, Colorado
John P. Murphy
County Commissioner
Boulder, Colorado
James J. Nolan
City Councilman
Denver, Colorado
Robert F. Clement
County Commissioner
Golden, Colorado
Thomas G. Thomas
Councilman
Arvada, Colorado
Dennis Champine
Councilman
Aurora, Colorado
Robert G. Trenka
Councilman
Denver, Colorado
Doris Durdy
Mayor Pro Tern
Brighton, Colorado
Norman A. Smith
Councilman
Broomfield, Colorado
Marjorie Christiansen
Council woman
Commerce City, Colorado
George N. Drake
Councilman
Edgewater, Colorado
Douglas T. Sovern
Councilman
Englewood, Colorado
-------
Local Elected Officials (continued)
Arthur J. Tice
Councilman
Federal Heights, Colorado
Lu Ella Terry
Councilwoman
Glendale, Colorado
Ruben Hartmeister
Councilman
Golden, Colorado
Alfred W. Vitt
Councilman
Greenwood Village, Colorado
Don DeDecker
Councilman
Lakewood, Colorado
Brad Stelling
President Pro Tern of Council
Littleton, Colorado
Harold T. Hodges
Councilman
Northglenn, Colorado
Jerrold W. Todd
Councilman
Sheridan, Colorado
Joseph E. McCloskey
Councilman
Thornton, Colorado
Fred Allen
Councilman
Westminster, Colorado-
Robert G. Howard
Alderman
Wheat Ridge, Colorado
Public Interest Groups
Colorado Open Space Council (5)1
Denver, Colorado
Rocky Mountain Center on Environment
Denver, Colorado
Thome Ecological Institute
Boulder, Colorado
Colorado Wildlife Federation
Boulder, Colorado
Zero Population Growth
Denver, Colorado
National Wildlife Federation
Washington, D.C.
Environmental Action Committee
Denver, Colorado
Environmental Impact Assessment
Project
Washington, D.C.
Mr. Mohammed L. Ashley
Environmental Defense Fund
Denver, Colorado
PREACT
Denver, Colorado
Friends of the Earth
Denver, Colorado
League of Women Voters of Colorado (5)2
Denver, Colorado
League of Women Voters of
Arapahoe County
Denver, Colorado
League of Women Voters of Boulder
Boulder, Colorado
1 5 copies provided to Colorado Open Space Council
2 5 copies provided to League of Women Voters of Colorado
-------
Public Interest Groups (continued)
Special Associations
League of Women Voters of Denver
Denver, Colorado
League of Women Voters
of Jefferson County
Sierra Club
Denver, Colorado
The Wilderness Society
Denver, Colorado
Colorado Aiken Audubon Society
Denver, Colorado
Plan Boulder
Boulder, Colorado
Plan Jeffco
Lakewood, Colorado
Trout Unlimited
Denver, Colorado
Historic Denver
Denver, Colorado
Keep Colorado Beautiful
Denver, Colorado
Plan Metro Denver
Denver, Colorado
Denver Parks and Recreation
Foundation
715 South Franklin
Denver, Colorado 80209
Adams County Chamber of Commerce
Denver, Colorado
American Issues Forum of Denver
Denver, Colorado
American Lung Association
of Colorado
Denver, Colorado
American Water Works Association
Denver, Colorado
American National Cattlemen's
Association
Denver, Colorado
Asphalt Institute
Denver, Colorado
Association of Commerce and Industry
Denver, Colorado
Building & Construction Trades
Council of Colorado
Denver, Colorado
Citizens for Sensible Water Use
Denver, Colorado
Colorado Association of
Wheat Growers
Denver, Colorado
Colorado Automobile Dealers
Association
Denver, Colorado
Colorado Health Care Association
Denver, Colorado
Colorado Heart Association
Denver, Colorado
-------
Special Associations (continued)
Colorado Medical Society
Denver, Colorado
Colorado Pollution Control Association
Denver, Colorado
Colorado Public Expenditure Council
Denver, Colorado
Colorado Public Interest
Research Group, Inc.
Denver, Colorado
Mr. Howard Hicks
Denver Chamber of Commerce
Denver, Colorado
Downtown Denver, Inc.
Denver, Colorado
Englewood-United Suburban
Chamber of Commerce
Englewood, Colorado
Farmers Union
Denver, Colorado
Golden Chamber of Commerce
Golden, Colorado
Home Builders Association
of Metropolitan Denver
Denver, Colorado
Independent Automobile Dealers
Association of Colorado
Denver, Colorado
Arvada Chamber of Commerce
Arvada, Colorado
Aurora Chamber of Commerce
Aurora, Colorado
Brighton Chamber of Commerce
Brighton, Colorado
Broomfield Chamber of Commerce
Broomfield, Colorado
Boulder Chamber of Commerce
Boulder, Colorado
Evergreen Chamber of Commerce
Evergreen, Colorado
Littleton Chamber of Commerce
Littleton, Colorado
Westminster Chamber of Commerce
Westminster, Colorado
Lakewood Chamber of Commerce
Lakewood, Colorado
South Denver Chamber of Commerce
Denver, Colorado
Wheat Ridge Chamber of Commerce
Wheat Ridge, Colorado
Legis 50
Englewood, Colorado
Lyon Collins and Company
Denver, Colorado
Metropolitan Denver Retail
Merchants Association
Denver, Colorado
National Environmental
Health Association
Environmental Problems Cormittee
Denver, Colorado
Colorado Energy Research Institute
Golden, Colorado
American Society of Landscape
Architects
Denver, Colorado
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Special Associations (continued)
Arapahoe Medical Society
Englewood, Colorado
Center for Research and Education
Denver, Colorado
Colorado Municipal League
Denver, Colorado
Others
Mr. Ron Otsaki
Commerce City, Colorado
Ms. Marcy Abling
Arvada, Colorado
Urban Conservatory
Denver, Colorado
Denver Research Institute
University of Denver
Denver, Colorado
Metro Denver Urban Coalition
Denver, Colorado
Mr. DeWitt John
Denver, Colorado
Mr. J. K. Smith
%Colorado Counties
Denver, Colorado
Mr. Jay D. Jurie
CARA
Denver, Colorado
Ms. Marg Ann Barton
Denver, Colorado
Ms. Darleen Ekland
Denver, Colorado
Mr. John Bermingham
Denver, Colorado
Ms. Ann Herbert
Wheat Ridge, Colorado
•ft U.S. Government Printing Office: 1977-779-516/202 Region 8
Mr. Chuck Hillestad
Denver, Colorado
Mr. Jack Anthony
PARC
Denver, Colorado
Mr. Bill Lamont, Jr.
Boulder, Colorado
Ms. Kay Collins
Conservation Library
Denver Public Library
Denver, Colorado
Jefferson County Open Space
Golden, Colorado
PLAN CD Newsletter
Bureau of Community Services
Denver, Colorado
Community Design Center
University of Colorado at Denver
Denver, Colorado
Mr. Belmont Evans
Community Noise Control Association
State Health Department
Denver, Colorado
Ms. Carol Carl in
Lakewood, Colorado
Mr. Mike Moore
Evergreen, Colorado
Mr. Dwight Filley
Denver, Colorado
Ms. less McNulty
Boulder, Colorado
Ms. Mikki Lofft
Denver, Colorado
Ms. Susan Thornton
Littleton, Colorado
Ms. Vim K. Wright
Denver, Colorado
Mr. Dick Morrow
Wheat Ridge, Colorado
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