EPA 9IO/9-77-043C EPA-IO-WA-KING-SEA-WWTW-77
DRAFT
ENVIRONMENTAL IMPACT STATEMENT
SEPTEMBER 1977
\
METROPOLITAN SEATTLE
ALKI
VOLUME II
KING COUNTY, WASHINGTON
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION X, SEATTLE. WASHINGTON
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DRAFT ENVIRONMENTAL IMPACT STATEMENT
FOR
METROPOLITAN SEATTLE
Volume II
Alkt
Number: EPA 910/9-77-043C
King County, Washington
Prepared jointly by:
Environmental Protection Agency,
Region X
Seattle, Washington 98101
Municipality of Metropolitan Seattle
Seattle, Washington
Washington State Department of Ecology
Olympia, Washington
With the Assistance of
James M. Montgomery, Consulting Engineers, Inc.
Pasadena, California/Boise, Idaho
Approved by:
Regional Administrator
August 25, 1977
Date
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INTRODUCTION
A. Action Sponsor
The action sponsor is the Municipality of Metropolitan
Seattle (METRO) for purposes of compliance with the
State Environmental Policy Act (SEPA Chapter 43..21C RCW)
and the Federal Environmental Protection Agency for the
purposes, of compliance with the National Environmental
Policy Act (NEPA).
B. Lead Agency, Responsible Official and Contact Person
For NEPA Compliance
Lead Agency: Environmental Protection Agency,
Region X
1200 6th Avenue
Seattle, Washington 98101
Responsible Official: Donald P. DuBois
Regional Administrator
Contact Person: Roger K. Mochnick
Project Officer, Environmental
Evaluation Branch
For SEPA Compliance
Lead Agency: Municipality of Metropolitan Seattle
600 First Avenue
Seattle, Washington 98104
Responsible Official: Neil Peterson
Executive Director
Contact Person: Peter S, Machno
Manager, Environmental Planning
Division
C, Authors and Contributors to Draft Environmental Impact
Statement
11
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Introduction
Participating Agencies: Environmental Protection Agency
Department of Ecology
Municipality of Metropolitan
Seattle
Advisory Agencies: City of Seattle
King County
Puget Sound Council of Governments
Consultants: James M. Montgomery, Consulting Engineers,
Inc. (Environmental Impact Statement)
Metropolitan Engineers (Facility Plan)
Human Resources Planning Institute. (Socio-
economic studies)
D. Licenses and Permits Required to Implement Wastewater
Facilities Plan
Building, grading, complex source permit, shoreline
permit and other local governmental permits would be
required before implementing most of the alternatives
described herein. Eligibility for grant funding by EPA
and DOE would be determined after completion of the
Final Facility Plan and EIS.
E. Location of EIS Background Data
Municipality of Metropolitan Seattle
Environmental Planning Division
SEPA Information Center
Room 404
600 First Avenue
Seattle, Washington 98104
F. Cost to Public for a Copy of the EIS
No charge while supply lasts.
G. Date of Issue of Draft EIS
This Draft Environmental Impact Statement was made
available to the Council' on Environmental Quality (CEQ)
and the Public on September 23, 1977.
H. Final Due Date for Public and Agency Comments
The final date for submittal of public and agency comments
is November 11, 1977. All comments should be sent to
Mr. Roger K. Mochnick, Environmental Evaluation Branch,
Environmental Protection Agency, 1200 Sixth Avenue,
Seattle, WA 98101.
111
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TABLE OF CONTENTS
List of Figures
List of Tables
Distribution List
Summary of EIS Content
Description of Proposal
Preface
I. CHAPTER I - BACKGROUND
Site Constraints and Issues
II. CHAPTER II - EXISTING ENVIRONMENTAL CONDITIONS
The Physical Environment 9
Topography of the Alki Site 9
Geology and Soils at Alki 10
Seismology at Alki 10
Duwamish West Waterway Site Geology and Soils 11
South Park Site Geology and Soils 11
Diagonal Avenue Site Geology and Soils 12
Harbor Avenue S.W. Geology and Soils 12
Seismicity of Alternative Sites 13
Puget Sound Sediments Off Alki Point 13
Climate and Air Quality at Alki 13
Odors at Alki 14
Climate and Air Quality in the Duwamish Valley 14
Water Resources 15
Biotic Environment 19
Terrestrial Ecology 19
Marine Habitats 19
Natural Resources and Energy 23
The Human Environment 23
Land Use 24
Legal and Institutional 24
Agency and Neighborhood Goals 24
IV
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Table of Contents
Economics and Costs 30
Employment 30
Social, Recreational and Cultural 31
Archeological and Historical 31
Health and Safety 31
Aesthetics and Nuisance 32
III. CHAPTER III - ALTERNATIVES AND IMPACTS 35
General 35
Development of Alternatives for Alki 36
Service Area 37
Treatment Process 37
Combined Sewer Overflows 38
Effluent Disposal 38
Sludge Management 38
Flow and Waste Reduction Measures 38
Regional Alternatives 40
Alternative A - No Action 41
Alternative B - Metro Comprehensive Plan
(No Action Pursuant to PL 92-500) 41
Alternative C - Major Combined Sewer Over-
flow Control 41
Alternative D - Partial Combined Sewer
Overflow Control 43
Alternative E - Secondary 43
Alternative F - Secondary/Southern Strategy 43
Alternative G - Secondary/West Point Phaseout
Option 43
Alternative H - Deconsolidation/Reclamation 44
Alternative A (No Action) 46
General Description 46
Service Area 46
Collection System 46
Wastewater Characteristics and
Treatment Facility 48
Sludge Characteristics and Management 52
Impacts 52
Geology, Soils and Topography 52
Air Quality and Odors 53
Water Quality 53
Biology 54
Natural Resources and Energy 57
The Human Environment 58
Mitigation Measures 59
Unavoidable Adverse Impacts 59
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Table of Contents
Alternative B Metro Comprehensive Plan No
Action Pursuant to PL 92-500 60
General Description 60
Impacts 62
Geology, Soils and Topography 62
Air Quality and Odors 62
Water Quality 63
Biology 63
Natural Resources and Energy 66
The Human Environment 67
Mitigation Measures 68
Unavoidable Adverse Impacts 69
Alternative C - Major Combined Sewer
Overflow Control 71
General Description 71
Impacts 72
Geology, Soils and Topography 72
Air Quality and Odors 76
Water Quality 76
Biology 77
Natural Resources and Energy 80
The Human Environment 80
Mitigation Measures 83
Unavoidable Adverse Impacts 83
Alternative D - Partial Combined Sewer
Overflow Control 85
General Description 85
Impacts 87
Geology, Soils and Topography 87
Air Quality and Odors 88
Water Quality 88
Biology 89
Natural Resources and Energy 92
The Human Environment 92
Mitigation Measures 94
Unavoidable Adverse Impacts 94
Alternatives E, G and H - Secondary 96
Impacts 98
Geology, Soils and Topography 98
Air Quality and Odors 99
Water Quality 99
Biology 100
Natural Resources and Energy 102
The Human Environment 102
Mitigation Measures 104
Unavoidable Adverse Impacts 105
VI
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Table of Contents
Alternative F - Secondary Treatment/Southern
Strategy 106
Impacts 108
Geology, Soils and Topography 108
Air Quality and Odors 109
Water Quality 109
Biology 110
Natural Resources and Energy 113
The Human Environment 113
Mitigation Measures 115
Unavoidable Adverse Impacts 116
Summary of Impacts 117
Geology, Soils, Topography 117
Air Quality and Odors 117
Water Quality 118
Biology 119
Natural Resources and Energy 122
The Human Environment 122
IV- CHAPTER IV - CITIZEN AND AGENCY INVOLVEMENT 127
APPENDICES
APPENDIX A - ELEMENTS OF THE ENVIRONMENT A-l
APPENDIX B - REFERENCES B-l
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Table of Contents
LIST OF FIGURES
Figure
1-1 Metro Treatment Plant Service Areas 2
1-2 Aerial View of Alki 4
1-3 Aerial View of Harbor and Diagonal
Avenue Sites 5
2-1 Sandy Gravel Tideland 20
2-2 Rock and Cobble Tideland 21
3-1 Metro 201 Facility Plan Service Area
Alternatives 42
3-2 Alki Point Service Areas 47
3-3 Alternative B - Preliminary Treatment
Improvements 61
3-4 Alternative C - Wet Weather Plant -
Primary Treatment 73
3-5 Alternative C - Alki Wastewater Treat-
ment Plant - Abandon 74
3-6 Alternative D - Enhanced Primary
Treatment 86
3-7 Alternatives E, G and H - Secondary
Treatment 97
3-8 Alternative F - Secondary Treatment -
Air Activated Sludge 108
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Table of Contents
LIST OF TABLES
Table Page
2-1 Summary of Pollutant Concentrations 16
3-1 Summary of Alternatives for 2005 -
Alki and Duwamish 45
3-2 Sludge Trucking Traffic 126
IX
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DISTRIBUTION LIST
Places of Public Availability
Public Libraries
Seattle Libraries
Main Branch
Montlake Branch
University Branch
West Seattle Branch
Magnolia Branch
Broadview Branch
Puget Sound Council of Government Library
King County Library
Main Branch
Richmond Beach Branch
Bellevue Branch
University of Washington
Reference Library
Metro and EPA Public Information Centers
The Environmental Protection Agency
Seattle Municipal Reference Library
Metro Library
King County Clerk of the Council
State of Washington—Office of Community Development
Federal Agencies
Council on Environmental Quality
U. S. Department of Agriculture
U. S. Department of Defense
U. S. Department of Interior
U. S. Department of Health, Education and Welfare
U. S. Department of Housing and Urban Development
U. S. Department of Transportation
Federal Energy Office
National Marine Fisheries Service
Advisory Council on Historic Preservation
Members of Congress
Warren G. Magnuson, U. S. Senate
Henry M. Jackson, U. S. Senate
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Distribution List
John E. Cunningham, U. S. House of Representatives
Joel Pritchard, U. S. House of Representatives
State Agencies
Office of the Governor
Department of Ecology
Department of Fisheries
Department of Natural Resources
Department of Game
Department of Social and Health Services
Department of Commerce & Economic Development
The State Ecology Commission
State Parks and Recreation Commission
State Oceanographic Commission
State Utility and Transportation Commission
Local Agencies and Interested Groups
Metro Council Members
City of Seattle Agencies:
City Council Central Staff
Environmental Review Committee
Department of Community Development
Office of Policy Planning
Department of Parks and Recreation
Department of Engineering
Department of Public Works
Water Department
Port of Seattle, Director of Planning
County Agencies:
Administrator, King County
Seattle - King County Department of Health
Department of Budget & Program Planning
Department of Planning & Community Development
Department of Public Works
Puget Sound Council of Governments
Snohomish Metropolitan Municipal Corporation-King County
(SNOMET)
Puget Sound Air Pollution Control Agency
Chairperson, Citizens's Water Quality Advisory Committee
Chairperson, Metropolitan Sewer Advisory Committee
City of Renton
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Distribution List
City of Edmonds
City of Lynnwood
City of Black Diamond
Metro's component and contracted agencies
National Wildlife Federation
Friends of the Earth
Sierra Club
Audubon Society
Washington Environmental Council
Institute of Environmental Studies (University of Washington)
Ecotope Group
This Draft Environmental Impact Statement was made available
to the Council on Environmental Quality (CEQ) and the public
on September 23, 1977.
XII
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SUMMARY OP DRAFT EIS CONTENTS
The Draft EIS is summarized in terms of the proposal,
the alternatives considered, the direct and indirect impacts
on the environment, mitigation measures and mitigating
measures to eliminate adverse impacts.
The Proposal
The Municipality of Metropolitan Seattle has prepared a
Draft Facility Plan for Puget Sound Plants to the year 2005.
Alternatives in the Draft Facility Plan are focused on
facilities at West Point, Alki, Carkeek Park, and Richmond
Beach, but other sites within these designated service areas
have been considered as options. The Metro plant at Renton
is not included in the proposed facilities, but effects of
alternatives on Renton are described since Renton is an
integral part of the Metro system.
This Draft EIS summarizes the impacts of the alternatives
for the Alki plant and service area as well as alternative
sites in the Duwamish industrial area.
Regional Alternatives
The eight regional alternatives are summarized below,
particularly as they affect Alki or the Duwamish area. The
Draft EIS analyzes the impacts of the eight regional
alternatives proposed in the Draft Facilities Plan, as they
would be applied to Alki. Each alternative is evaluated on
a co-equal basis in the Draft; no recommended alternative
has been selected.
Regional alternatives were developed to address, in
various combinations, four polar issues: water quality, site
impacts, the law (PL 92-500) and costs. Components considered
in developing alternatives included service area, collection
system and transfer interceptors, treatment process, plant
site, treated wastewater discharge location, combined sewer
overflow control and sludge management. Interceptors to
serve new growth areas were not included.
Two of the alternatives (A and B) are "no action" alter-
natives required by SEPA and NEPA. Two of the alternatives
(C and D) address combined sewer overflows, a local water
quality problem. Four alternatives (E,F, G and H) provide
secondary treatment and other variable features. From the
eight regional alternatives, it is possible to derive hybrid
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Summary of Draft EIS Contents
alternatives that select components from more than one
alternative and blend them into a new alternative, such as
secondary treatment plus combined sewer overflow controls.
Alternative A - No Action
No capital expenditure would be made for expansion,
modification or upgrading of treatment plants and no
construction of new interceptors during the planning period
(until 2005). Alternative A is evaluated to meet SEPA "no
action" requirements.
Under Alternative A, Alki would continue to provide
primary treatment, with a capacity in 2005 of 10 mgd average,
30 mgd peak. No capital improvements would be made at the
plant, and CSO's would continue in their present pattern.
Alternative B - Metro Comprehensive
Plan (No Action Pursuant to PL 92-500)
Plant upgrading and transfer interceptor construction
would be done according to the Metro Comprehensive Plan.
Alternative B is evaluated as the "no action" alternative
pursuant to PL 92-500 and NEPA requirements and serves as
the baseline for other alternatives. Puget Sound plants
(West Point, Alki, Carkeek Park and Richmond Beach) would
be retained with primary treatment. Improved sludge manage-
ment and disinfection practices would be provided in
Alternative B and all following alternatives. Four new
transfer interceptors and improvements to the Alki outfall
would be included.
At Alki,the outfall would be improved by 1986 for better
dilution of wastewater. Primary treatment for 10 mgd average,
30 mgd peak flow would be provided.
Alternative C - Major Combined
Sewer Overflow Control
Major portions of combined sewer overflows would be
controlled by transfer from fresh to salt water and/or
treatment. The existing Puget Sound plants would be
upgraded to provide enhanced primary treatment by physical/
chemical treatment of solids during the summer. A new wet
weather enhanced primary treatment plant would be constructed
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Summary of Draft EIS Contents
in the lower Duwamish industrial area and the Alki plant
would be abandoned, both in 1995.
Alki would be upgraded to enhanced primary treatment
by addition of chemicals in 1983, which would require
construction of chemical storage and feeding equipment. A
new digester and dewatering facilities would be built for
sludge handling. All new equipment would fit on the existing
plant property. The outfall to Puget Sound would be
extended.
In 1995, flows from Alki would be transferred to other
plants, so that the Alki facilities could be demolished and
the site abandoned. Through a new connection to the
Duwamish, wet weather flows of 30 mgd peak from Alki would
be transferred to a new 250 mgd peak wet weather plant in
the Duwamish. The Duwamish plant, planned for a Diagonal Way
site, would provide enhanced primary treatment for discharge
to the Duwamish estuary. In dry weather, Alki flows would
be routed to West Point.
Alternative D - Partial Combined
Sewer Overflow Control
Wet weather combined sewer overflows would be reduced
to Lake Washington, Lake Union, and the West Seattle shoreline.
The four Puget Sound plants would be upgraded to enhanced
primary treatment with chemical addition during the summer
for improved solids removal.
Alki would be upgraded to an enhanced primary plant by
1985 and would operate as such during the planning period
to 2005. Chemical storage and feeding equipment plus a
sludge digester and dewatering facilities would be constructed
at the existing site. The outfall to Puget Sound would be
extended.
Alternative E - Secondary
Secondary treatment would be added to the West Point,
Alki,and Richmond Beach wastewater treatment plants. The
Carkeek Park plant would provide primary treatment for wet
weather flows only beginning in 1985; dry weather flows
would be pumped to West Point. Carkeek Park would probably
be abandoned by 1995, depending on City of Seattle Sewer
separation programs.
Secondary treatment would be provided for 10 mgd
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Summary of Draft EIS Contents
average, 30 mgd peak capacity at Alki by 1983. The secondary
aeration basins and clarifiers would require the use of land
which presently contains one ballfield adjacent to the plant.
New sludge digestion and dewatering facilities would be
built to handle the additional solids load.
Alternative F - Secondary/Southern Strategy
Secondary treatment would be provided at Richmond Beach
and West Point (with a reduced service area). A major new
secondary treatment facility would be constructed in the
Duwamish industrial area in 1985; the Alki plant would be
abandoned at that time. A new outfall off Alki Point would
be built for discharging effluent from the Duwamish (and
Renton) plants. The Carkeek Park plant would provide
primary treatment for wet weather flow only beginning in
1985; dry weather flows would be pumped to West Point.
At Alki, interim improvements would be made by 1978,
and the plant would provide primary treatment until being
demolished and abandoned in 1985. With completion of the
Alki to Duwamish transfer interceptor and the new Duwamish
plant in 1985, all Alki flows would be transferred there.
The Duwamish plant, planned for a site on Harbor Avenue S.W.
would provide secondary treatment for 45 mgd average,
145 mgd peak flows. Treated wastewater from the Duwamish
aid the Renton (99 mgd average, 259 mgd peak capacity) plant
would be discharged to Puget Sound through a new outfall,
to be constructed off Alki Point.
Alternative G - Secondary/West
Point Phaseout Option
Secondary treatment would be provided at the Alki and
Richmond Beach plants. West Point would continue as a
primary treatment plant for wet weather flows only, beginning
in 1985. A new secondary treatment plant in the Interbay
area (Commodore Way or Golf Park sites) would be constructed.
The Carkeek Park plant would provide primary treatment for
wet weather flows only beginning in 1985; dry weather flow
would be pumped to West Point.
At Alki, regional Alternative G would be the same as
Alternative E: secondary treatment, expanded sludge handling
facilities and an extended outfall.
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Summary of Draft EIS Contents
Alternative H - Deconsolidation/Reclamation
Secondary treatment would be provided at West Point,
Alki, Carkeek Park and Richmond Beach. Areas of growth
would be served by new inland plants with local effluent
and sludge re-use possible. Advanced waste treatment would
be provided at new North and South Lake Sammamish plants.
A new secondary plant at Kenmore would discharge treated
effluent to Puget Sound.
At Alki, regional Alternative H would be the same as
Alternative E: secondary treatment, expanded sludge handling
facilities and an extended outfall.
Environmental Impacts
The primary (direct) and secondary (indirect) impacts
of each alternative are described by categories in the
physical, biological and human environments plus natural
resources and energy. A summary of the major effects of
each alternative is described below.
Alternative A (No Action)
Alternative A, which would continue sewerage service
to the present sewered population but provide no new service
or capital improvements, would have comparable impacts in
2005 as existing conditions. Combined sewer overflows would
produce localized adverse impacts along Elliott Bay and Alki
Point. Shellfishing areas at Alki would continue to show
violations of bacterial standards in the water. Eelgrass
beds at Alki, important in herring production and local
fisheries, could be affected by CSO's and inadequate dilution
at the existing outfall. In Puget Sound, the discharge of
solids, metals, toxicants,and other materials would continue
at present rates. Although effects,as measured to date,from
present discharges have been very minor, the possibility of
subtle, long-term impacts must be considered.
The site impacts at Alki would continue to affect the
nearby residential areas. If uncontrolled, odors would
exist during the planning period. Traffic from plant
employees and sludge trucks would still pass through the
neighborhood. However, the plant would not be expanded,
so the ballfields would not be affected.
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Summary of Draft EIS Contents
Alternative A would not comply with the secondary
treatment requirements of PL 92-500, but the implementation
of this alternative is not realistic. It is evaluated
nerely to show the consequences of no action.
Alternative B - (Metro Comprehensive Plan
No Action Pursuant to PL 92-500)
The only change in water quality at Alki relative to
existing conditions would be better dilution and dispersal
of primary effluent from the improved outfall. Since the
discharge will likely be in mid-channel where mixing condi-
tions should be improved, the possibility of solids, metals,
pathogens or toxicants reaching the shoreline would be reduced.
In addition, the more effective disinfection should benefit
microorganism destruction and water quality near shellfishing
areas. Combined sewer overflow would continue as today.
Site impacts at Alki would continue with the continued
plant operation in a residential neighborhood. Traffic
associated with plant personnel and sludge trucks would
continue. Odor, unless controlled, would remain a nuisance
at Alki. Recreational use of the nearby playing fields
would not be changed.
This alternative does not comply with PL 92-500 re-
quirements for secondary treatment.
Alternative C - (Major Combined
Sewer Overflow Controls )
Under Alternative C, the Alki plant would provide en-
hanced primary treatment during the summer season from 1983
to 1995. During this period, approximately the same total
flow would be added as in Alternative B. The 20 percent
reduction in organic materials, in solids, and associated
metals, toxicants, and other components plus the improvement
in the Alki outfall should be beneficial to the local beaches
and intertidal areas, but these impacts would correspond
closely with Alternative B. By 1995, the discharge of ef-
fluent from Alki would be eliminated, which should be bene-
ficial to the local water quality.
The discharges from the new Duwamish plant, beginning in
1995, could have adverse effects on the Duwanish estuary,
where 250 mgd peak would be discharged in storm periods. Since
the Elliott Bay-to-Duwamish migratory fish route already re-r.
ceives municipal and industrial pollutants, Alternative C would
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Summary of Draft EIS Contents
intensify stress on these species. At Alki Beach, combined
sewer overflow would be almost completely eliminated, a
benefit to the intertidal areas and local beaches.
Because no substantial changes would occur at Alki be-
fore 1995, the site impacts would continue. Unless controlled,
odor would remain a problem. Recreational use of the play-
ing fields could continue. After abandonment, the Alki site
could be converted to more compatible land uses.
At the Duwamish (Diagonal Way) site, socioeconomic im-
pacts of constructing and operating the new plant will oc-
cur. A study of this area is in progress.
Alternative C does not comply with the PL 92-500 re-
quirements for secondary treatment as currently written.
Consequences could include fines and ineligibility for
grant funding.
Alternative D - (Partial CSO Control)
The use of enhanced primary treatment at Alki, begin-
ning in 1985 and continuing through the duration of the
study period, would reduce solids and organics by 22 percent
relative to Alternative B. Reductions in metals, pathogens,
toxicants and other parameters would follow- The improved
outfall and disinfection should result in better dispersion
and reduced possibility of contamination along the beach.
Combined sewer overflows at Alki Beach would decrease, but
only by 18 percent.
At the Alki plant site, temporary disturbance would
occur during dewatering activities plus extending the out-
fall. Otherwise the plant impacts would remain in terms of
odor. Sludge truck traffic would decrease with the intro-
duction of dewatering equipment to reduce sludge volume.
The new construction would not affect the adjacent ball-
fields.
This alternative would not comply with the secondary
treatment requirements of PL 92-500, with possible conse-
quences on penalties and funding.
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Summary of Draft EIS Contents
Alternative E -
(Secondary)
Implementing secondary treatment at Alki would reduce
solids and organics loads to Puget Sound by over 70 percent
at that location. Associated metals, pathogens, and toxi-
cants would also decrease. Combined with the improved outfall
and disinfection techniques, this alternative should substan-
tially benefit local water quality, particularly in areas with
shellfish and eelgrass beds. The magnitude of any changes
in diversity, abundance, and composition in bottom communities
should be less than may occur under Alternative B. The like-
lihood of contaminating shellfishing areas would be substan-
tially reduced by improved effluent quality and dispersion.
However, combined sewer overflow would continue as at present.
Construction impacts for new secondary aeration basins
and clarifiers plus the improved outfall would be adverse but
temporary. Since land for expansion is not available on the
existing plant site, the new secondary facilities would require
most of the land now occupied by one of the two adjacent ball-
fields. The impact on local recreation would be the loss of
this ballfield. Unless controlled, the odors in the neighbor-
hood around Alki would continue.
This alternative would comply with the secondary treat-
ment requirement of PL 92-500. Timing requirements of the
NPDES permit, dated June 14, 1977, include completion of the
Facility Plan and EIS by June 30, 1978 followed by develop-
ment of a compliance schedule for design and construction to
meet the required 1983 date for completion of best practi-
cable treatment facilities.
Alternative F -
(Secondary/Southern Strategy)
The principal impacts from this alternative would result
from treating Alki area wastewater at a new Duwamish plant
beginning in 1985. The secondary effluent from the Duwamish
plant (45 mgd average, 145 mgd peak) plus the Renton plant
(99 mgd average, 259 mgd peak) would then be discharged off
Alki Point to Puget Sound through a new outfall. This dis-
charge would be approximately 50 percent larger in terms of
flow than the present West Point discharge. Information on
existing conditions off Alki is limited, so more studies are
needed before exact impacts can be determined there. A pre-
liminary conclusion is that nutrients from secondary effluent
could influence the size of plankton blooms near Restoration
Point. The increase in nutrients and solids loads to Puget
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Summary of Draft EIS Contents
Sound would be paralleled by increased loads of toxicants
and heavy metals, perhaps of a similar magnitude.
Abandoning Alki in 1985 would allow the land to be
converted to more compatible land uses. Until that time,
impacts on the residential area from odors and traffic would
continue.
At the Duwamish site, socioeconomic impacts have not
been determined, but some work is in progress.
Alternative F complies with the secondary treatment
requirement of PL 92-500. Timing requirements of the NPDES
permit include completion of the Facility Plan and EIS by
June 30, 1978 followed by development of a compliance sche-
dule for facility design and construction.
Alternative G -
(Secondary/West Point Phaseout Option)
Since the implementation of this alternative at Alki would
involve the same facilities and service area as Alternative E,
the impacts would correspond exactly with Alternative E.
Alternative H -
(Deconsolidation/Reclamation)
Implementation of this alternative would require the
same facilities for the Alki service area as Alternative E;
thus, the impacts would be identical.
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Summary of Draft EIS Contents
Mitigation Measures
Possible mitigation measures to alleviate or eliminate
adverse impacts at the Alki plant site and service area plus
the possible Duwamish plant sites include the following:
1. Instituting odor control measures at Alki in the
near future regardless of other decisions on the
wastewater facilities; costs of odor control meas-
ures expected by end of July 1977 from Metro
(Alternatives B, C, D, E, F, G, and H).
2. Covering secondary clarifiers and constructing tennis
courts to replace recreational use of one ballfield
(Alternatives E, G, and H).
3. Conducting a comprehensive study off Alki Point to
accurately determine existing water quality, biology,
and currents before constructing a major new outfall
there (Alternative F).
4. Landscaping the Alki plant site, particularly to
screen views from above (Alternatives B, C, D, E,
F, G, H).
5. Dewatering sludge on-site at Alki to reduce sludge
truck traffic (Alternative B).
6. Operating chemical addition and enhanced primary
treatment at Alki all year to reduce loads of solids,
metals, and other parameters to Puget Sound (Alter-
natives C and D).
7. Obtaining an adequate data base in the Duwamish area
to determine socio-economic impacts (Alternatives C
and F).
8. Investigating new treatment plant locations in the
Duwamish.
Unavoidable Adverse Impacts
The remaining impacts on water quality, biology, socio-
economics, sites, costs, energy and natural resources that
could not be mitigated by the previously mentioned measures
under each alternative would be unavoidable adverse impacts.
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Summary of, Drafit EIS Contents
DESCRIPTION OF THE PROPOSAL
A. Name of the Proposal and Sponsors
This information is contained in the Introduction and
in the Summary of Draft EIS Contents.
B. Location of the Project
The project location is described in Chapters I and III
the Draft EIS.
C. Other Agencies File Numbers on Proposal
The reader is requested to contact Mr. Roger Mochnick
(EPA) , Mr. John McDonnell (DOE), and Dr. Peter Machno
(Metro) for this information.
D. Identification of Construction Phasing and Future EIS
Requirements.
Chapter III contains this information.
E. Description of Physical and Engineering Aspects of the
Project.
These descriptions are summarized in Chapter ill
Draft EIS and are detailed in the Draft Facilities Plan.
F. Land Use Plans and Zoning Regulations
Chapter II of the Draft EIS describes existing and pro-
jected land use; Chapter III addresses whether the pro-
posal is consistent with these regulations.
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PREFACE
This Draft Environmental Impact Statement (EIS) evalu-
ates the impacts of alternative wastewater facilities de-
scribed in the Draft Facility Plan developed for the Muni-
cipality of Metropolitan Seattle (Metro). The alternatives
include wastewater treatment plants, transfer interceptor
sewers, combined sewer overflow control facilities and
sludge handling facilities that would be constructed and
operated by Metro. The major part of construction costs
could be provided by grants from the Environmental Protec-
tion Agency (EPA) and the Washington State Department of
Ecology (DOE).
The EIS has been prepared in response to federal and
state legislation plus local resolutions requiring that EPA,
DOE and Metro each fully consider the environmental impacts
and consequences of alternative projects prior to making a
final decision to proceed on a recommended project. The
respective responsibilities for the three agencies in the
EIS process were established for EPA in the National Environ-
mental Policy Act (NEPA), 42 U.S.C. Sec. 4321, et seq.; for
DOE in the Washington State Environmental Policy Act (SEPA)
Chapter 43.21C RCW; and for Metro in Metro Council Resolution
No. 2582.
In certain cases, significant environmental impacts could
result from the various wastewater facilities alternatives.
For example, alternatives for Metro's West Point, Alki and
Carkeek Park wastewater treatment plants may have signifi-
cant environmental impacts; similarly, an evaluation of
facilities on a regional level indicated that some signifi-
cant impacts should be considered. Therefore, a decision
was made to prepare an EIS on these projects to comply with
both NEPA and SEPA requirements. Rather than preparing
separate EIS documents at the appropriate time, the three
agencies agreed to prepare a joint EIS for the regional
facilities alternatives, plus the West Point, Alki and Car-
keek Park alternatives. In addition to satisfying both NEPA
and SEPA with the joint EIS, the agencies also chose a pro-
cedure designed to eliminate delays and duplication of effort
as well as to facilitate desirable interchange among the agen-
cies and with the public during the early stages of the EIS
process.
In another case, facilities would not cause significant
environmental impacts as defined in NEPA. Therefore, an
EIS, pursuant to SEPA (which would also serve as an envi-
ronmental assessment), was prepared for the Richmond Beach
site and service area.
xxiv
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Preface
For the total evaluation of the environmental impacts
of alternative facilities plans, the environmental analysis
has been organized as follows: Regional Analysis EIS (Vol-
ume I), West Point Treatment Plant EIS (Volume II), Alki
Treatment Plant EIS (Volume II), Carkeek Park Treatment
Plant EIS (Volume II), Richmond Beach Treatment Plant EIS
(pursuant to SEPA) (Volume II). Each site-specific docu-
ment (Volume II) is intended to be read with the regional
analysis (Volume I), with each such pair constituting a
complete EIS.
The production of this joint Draft EIS results from
close cooperation between EPA, DOE, and Metro. All three
agencies have been intimately involved with the review,
analysis, supplementation, and synthesis of materials fur-
nished by independent consultants hired to assist with the
preparation of the EIS. The City of Seattle, King County,
and the Puget Sound Council of Governments have also parti-
cipated in meetings and provided comments on preliminary
draft materials to ensure that local government concerns and
regional land use planning goals were incorporated in the
EIS.
EPA regulations on "Preparation of Environmental Impact
Statements" (40 CFR Part 6; 40 FR, April 14, 1975), Council
on Environmental Quality Guidelines for the "Preparation of
Environmental Impact Statements" (40 CFR Part 1500; 38 FR
20550, August 1, 1973), and the EPA "Manual for Preparation
Works, Facilities Plans, and 208 Area-wide Treatment Manage-
ment Plans" (July 1974) have been used in preparation of the
EIS. Likewise, SEPA Guidelines, adopted by the State Council
on Environmental Quality and incorporated by Metropolitan
Council Resolution No. 2582, have been followed insofar as
they are consistent with federal requirements.
Some of the alternatives described in the Draft EIS's
and Draft Facility Plans include the provision for secondary
treatment at Metro facilities by 1985. The twenty year plan-
ning period is from 1985-2005. These 1985 dates are not con-
sistent with the current PL 92-500 requirement for Best Prac-
ticable Treatment including secondary treatment by 1983.
According to the facility planning engineers, the 1985 date
may be more realistic than 1983 due to delays in the Step I
(planning process), and, thus, in the start dates for Step II
(design) and Step III (construction).
However, since the law currently requires Best Practi-
cable Treatment by 1983, the construction schedules will be
changed to reflect this. Due to time constraints, it was
not possible to change the dates in the Draft Plans and EIS's
The reader should note that any mention of secondary treat-
xxv
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Preface
ment in 1985 will be changed to 1983 in the Final Plans and
EIS's. The twenty-year planning period also changes to
1983-2003.
These changes may impact the analysis of alternatives in
several minor ways. First, there is a potential for a slight
saving in costs, due to the decrease in inflation associated
with an earlier start date. However, the need for this
earlier start date compresses the design and construction
schedules causing an increase in these costs. The two fac-
tors, one a potential savings and one an increase in costs,
will probably negate one another.
The new planning period, from 1983-2003, will cause
population projections and solids loading to decrease
slightly. This decrease, estimated at 2 percent, is well
within current sensitivity of the projections and should not
have a noticeable impact on the analysis.
All comments on this Draft EIS should be sent to the
EPA as the lead agency in the EIS process. Comments should
be addressed to Mr. Roger Mochnick, Environmental Evaluation
Branch, Environmental Protection Agency, 1200 Sixth Avenue,
Seattle, Washington, 98101. The EPA will then distribute
copies of the comments to DOE, Metro and the EIS consultant.
Comments will be used by the three agencies in preparing the
Final EIS and in their decision-making processes.
It is believed that this process best enables the agen-
cies involved to fully assess and consider all significant
physical, economic, and social effects of their proposal,
and public input thereon, prior to any significant decision-
making step. For this reason, the agencies have not attempted
to bias the decision to be reached by recommending any one of
the eight alternatives prior to full completion of the EIS
process, including the public hearings. Rather, the attempt
of this document is to present the decision makers and the
public with as complete an analysis as possible of each of
the alternatives so that a fully informed decision can be
made.
The remaining part of the decision-making process will
proceed under the following schedule:
October 25, 1977 Public hearing on Regional
Draft EIS
October 27, 1977 Public hearing on Alki Draft
EIS
XXVI
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Preface
November 1977
February 1978
March 1978
April 1978
April 1978
April 1978
A preferred alternative is
recommended by Metro in
conjunction with EPA and DOE
Final EIS is available
Public hearings on Final EIS
Metro Council decision
DOE decision
EPA decision
xxvi i
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CHAPTER I
BACKGROUND
The Alki wastewater treatment plant is one of five Metro
treatment plants that will be affected by the wastewater
management alternatives being considered in the 201 Facility
Plan. Figure 1-1 shows the treatment plants' locations and
the service areas tributary to each. This report, Volume II,
presents 'the impacts of these alternatives on the Alki service
area and its environment. Impacts of the alternatives on the
regional level and a background of the regional issues are
discussed in Volume I.
The Alki treatment plant services approximately 4,100 acres
adjacent to Puget Sound. This includes the west side of the
West Seattle residential area and extends south to include the
Fauntleroy area. The tributary area is almost entirely resi-*
dential, producing normal domestic sewage with no appreciable
industrial load.
The treatment plant was constructed by the City of Seattle
in 1958. It was designed for a dry weather flow of 10 million
gallons per day (mgd). The combined collection system is sub-
ject to high inflow and infiltration during storms. The de-
sign peak wet weather flow for the treatment facility is 30
mgd; flows in excess of 30 mgd are bypassed directly to Puget
Sound along the shoreline near Alki Point and the Duwamish.
Treated effluent is discharged to Puget Sound 1,300 feet off-
shore through a 42-inch diameter submarine outfall at a depth
of 79 feet below mean sea level. The Alki outfall is judged
to be inadequate in having no diffuser section and discharging
into shallow water near shore. The solids are digested on
site and trucked in liquid form to the Cedar Hills landfill for
final disposal.
At present, nine operating personnel are required to staff
the facility which has an operating cost of $378,000/yr.
Traffic generated by plant operation amounts to nine round
trips/day in addition to 1.7 round trips/day for sludge trucks.
-------
"*iiK£ I
1 '
RENTON SERVICE AREA
WEST POINT SERVICE AREA
ALKI SERVICE AREA
CARKEEK PARK SERVICE AREA
RICHMOND BEACH SERVICE AREA
METRO WASTEWATER TREATMENT PLAN'
METRO STUDY AREA BOUNDARY
SERVICE AREA BOUNDARY
i—i
'. ,: . I 1
• •, , /
'/~ ,'•••'/"^ I
,', ' ' 1
t ••' ' •
•
\ y>x w&j*;
** WV^Qj.
•M^S&i:^
r-^aV"'. "•-"--- t-\O»re . ~- • i ' ffi;
^sB^^wyy^1!
—V . • / , : 'V, ; •;• if
/ "' T //i ''>'•';;'
+ .;;• • •> -'-, ' •'• -.,, - ;_:-',^ :.,!,.
•V^.- .,f_ ^ ,•.. i --,--- : .
,-! ' >;'V.--'..V.- '.' I . - • . -• /
^d,,':':'\:'-^^
Figure 1-1
Metro Treatment Plant
Service Areas
e ,
-------
Background
More detailed descriptions of the service area and treat-
ment facility are included in Chapter III under the "No
Action" alternative.
SITE CONSTRAINTS AND ISSUES
The immediate proximity of residences to the Alki treat-
ment plant places severe constraints on plant operations and
expansion. An aerial view of Alki is shown in Figure 1-2.
Light onshore breezes carry odors directly onto neigh-
boring properties, triggering complaints from local resi-
dences. Based on comments at public meetings and workshops,
the odor near Alki is frequent and is a major concern of
residents. Metro has taken steps to reduce the odor by oper-
ating afterburners. Other odor control measures will be eval-
uated and priced near the end of July 1977.
The site is presently too small for parking and materials
storage. Access to the plant is along a narrow unpaved road
through residential areas. The road is not wide enough for
necessary truck maneuvers, and any increase in sludge hauling
traffic would increase traffic through the neighborhood.
Any expansion or upgrading at the site would consume a
part of one, and possibly two, baseball diamonds which consti-
tute the neighborhhod park. The site rests on solid bedrock,
necessitating explosives in excavation for new facilities.
The nearby discharge of fecal coliform bacteria during wet
weather overflows or inadequate diffusion at the outfall re-
sults in bacterial concentrations in waters along the beach
that exceed some public health limits for shellfishing and may
limit water contact recreation there.
To alleviate the site constraints cited above, abandon-
ment of the Alki treatment site was considered in two of the
regional alternatives evaluated in the Draft Facility Plan.
Alternative sites for both a wet weather treatment plant and
secondary treatment plant were considered in the lower Duwamish
area. An aerial view of the Duwamish area is shown in Figure
1-3.
The favored site for the wet weather treatment facility
would be at Diagonal Avenue where an abandoned treatment plant
still stands. The land available there could accommodate the
wet weather plant size. However, the site is directly across
the river from a recently discovered archeological site. Al-
though no survey has been made of the site it is considered to
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Background
Figure 1-2
Aerial View of Alki Looking in Northerly Direction
4
-------
Background
Figure 1-3
Aerial View of Harbor and Diagonal Avenue Sites
-------
Background
have high potential for archeological resources. As a result,
less favored optional sites, at South Park and the Duwamish
West Waterway near the river mouth, may receive more serious
consideration. These two sites, however, are built on sanitary
landfills, and piling would be required for supporting all
structural foundations. In addition to the foundation problems,
the sites located on sanitary landfill are prone to gas prob-
lems generated from organic matter decomposition.
Another site being considered in the lower Duwamish area
for the dry weather plant would be at Harbor Avenue S.W., where
sufficient land would be available for the larger, secondary
treatment plant. Again, it is believed that piling will be re-
quired for the support of all structural foundations.
Socioeconomic studies of the sites were not made, and
the opinions of the general public as well as the industrial
interests in the area on the use of these sites have not yet
been solicited. Metro staff is currently investigating the
Duwamish area in more detail, and the City of Seattle is
independently evaluating alternative sites.
At public workshops and community meetings, Alki
residents complained of odors, did not feel that current
odor control measures at the plant were successful and asked
for a clarification of the ownership of the ballparks.
Residents also questioned the effectiveness of the City of
Seattle "Forward Thrust" sewer separation program and the
wisdom of allowing in the past combined sewer overflows
adjacent to public beaches. It was pointed out that the
storm sewer outfall south of the plant blocks pedestrian use
of the beach by a stream of effluent.
Questions relating to regional issues were raised about
the natural flushing ability of Puget Sound, the fate of
heavy metals, the reasons for delay in adopting secondary treat-
ment, and the rate of inflation used in the cost projections.
The citizens expressed a desire to have a voice in the
design process and to have the plant moved if this could be
done without incurring costs substantially higher than that
for plant improvements at Alki. Priorities for on-site im-
provements included controlling odors, avoiding removal of
houses or the ballfield, construction additions over the
road toward the shore or under the ballfield, or designing
the plant site for multiple use (such as recreation).
Other comments concerned options on the ballfield, federal
funding limits, and the effect of plant expansion on pro-i
perty values.
-------
Background
An additional public workshop was held in June to inform
citizens of the eight proposed alternatives and solict their
comments on the site-specific impacts of each. Site concerns
were the same as expressed at earlier meetings (odors, pro-
perty values, baseball field), but the citizen sentiment was
that these concerns had been made known to Metro before.
Interest in regional issues was apparent by remarks on water
quality and impacts at a Duwamish site. Public hearings on the
Alki site and regional issues are planned for October"
November.,
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CHAPTER II
EXISTING ENVIRONMENTAL CONDITIONS
The following description of the environmental setting at
Alki and its potential alternative sites in the Duwamish Valley
is divided into the following categories for analytical pur-
poses: physical, biological and human. It is recognized that
the three overlap, but this artificial division ensures a thor-
ough analysis of relevant impacts. Emphasis is placed on
treatment plant sites, surrounding service areas, and adjacent
Puget Sound Waters. Additional information is provided in the
regional analysis which is Volume I of this series. A list
of the elements of the environment to be treated in this docu-
ment is appendixed, as required by SEPA.
The Alki service area is approximately 6.4 square miles,
as indicated on the map of Figure 1-1. The area is a pre-
dominately single-family residential area. It is one of the
older, more developed areas of Seattle.
THE PHYSICAL ENVIRONMENT
The following describes topography, geology, soils,
seismicity, climate, air quality, hydrographic features and
water quality (Metropolitan Engineers, Alki Facility Plan,
1977) .
Topography of the Alki Site
The Alki service area rises from Puget Sound in the west
and Elliott Bay in the north to elevations exceeding 400 feet.
Steep bluffs are found in the Duwamish Head area and in various
locations south of Alki Point above the shoreline of Puget
Sound. Longfellow Creek follows a northerly course toward
Elliott Bay cutting a moderately incised valley about three
miles in length. Much of the Alki service area slopes, a fac-
tor which influences peaking factors in combined sewer and
-------
Existing Environmental Conditions
urban drainage flows.
The Alki plant is situated in a primarily residential
area on a virtually level plateu approximately 5 feet higher
than, and parrallel to, Beach Drive, S.W., immediately adjacent
to the west. Two small ballfields are located to the north-
east bordering the plant; the ballfields, a part of the Bar
S playground, are approximately ten feet higher in elevation.
Residences at the east and north sides of the ballfields are
approximately 5 feet below the ballfields. The plant and
ballfields lie at the base of a rocky hill to the north/north-
west. The ballfields were constructed of cut material from
the hill and the plant site. Metro has an option to purchase
the adjacent playfield which is owned by the City of Seattle.
Geology and Soils at Alki
The predominant soils of the Alki service area are Vashon
till (well-consolidated clay, silt, sand, and gravel of glacial
origin) and undifferentiated pre-Vashon deposits (till, outwash
and interglacial deposts). The only non-glacial material found
in the service area is located at Alki Point where Oligocene
sedimentary rocks are exposed. They consist of well-cemented
marine siltstones and mudstone with some graywacke sandstone
and conglomerate beds.
Soils in the upland areas contribute to variable runoff
characteristics as infiltration is very slow, and undrained
or poorly drained depressions are common. Permeability is low
in all areas except within the outwash deposts. Being dense
and cohesive, excavation of these soils is difficult by hand
or with light power equipment.
When the southwesterly half of the Alki treatment plant
site was excavated, bedrock was encountered. It is believed
that the bedrock can be ripped off with heavy construction
equipment if the required excavation is not very deep. How-
ever, present information is insufficient for making any con-
clusive recommendations. For the purpose of foundation sup-
port evaluation, the physical properties of both the bedrock
and the overlaying soils should be established, and the sur-
face contours of the bedrock should be identified.
Seismology at Alki
Relative to other areas in metropolitan Seattle, West
Seattle sustained more serious damage during the 1965 earth-
10
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Existing Environmental Conditions
quake. Structural damage to older brick buildings and chim-
neys was common. This was thought to be the result of vib-
ration of the well-consolidated Pleistocene deposits which
exist there, rather than faulting or subsidence.
Earthquake hazard is a function of soil type in the
Puget Sound region. At Alki, structures on Alderwood and
Everett soils would experience an earthquake of magnitude
VII (Modified Mercalli Scale) one to five times in 133 years.
Seismic risk is moderate, such that before building at this
location, further study of near surface conditions is required
to plan construction.
Duwamish West Waterway Site Geology and Soils
The Duwamish West Waterway site was filled to its pre-
sent elevation with sanitary waste and other earth fills,
resulting in little uniformity. Though surface fill averages
20 feet in depth and is heterogeneous, investigations have
not encountered gas problems. Soil conditions demonstrate
the need for piling to support all structural foundations.
Seismic hazard risk is probably moderately high as fill is
unstable and likely to transmit long wave vibrations
(Rasmussen et al., 1974).
South Park Site Geology and Soils
The South Park transfer station site lies in the former
Duwamish river floodplain and delta. It was filled to present
elevation with sanitary waste and other earth fills. It
averages 20 feet in depth and is expected to have little
uniformity. A detailed soil study is necessary to determine
specific engineering procedures in developing the land.
Previous soils investigations did not encounter gas problems
in the fill. The surface fill was underlain by soft silt,
peat and very fine sand, which were in turn underlain by black
medium compact to compact fine to fine-medium sand. Ground-
water level fluctuated between elevations 3 and 7, being
higher during the winter months. Seismic hazard risk is high
for these loose, unstable soils (Rasmussen et al., 1974).
Piling will be required for supporting all structural
foundations. Treated timber piles or prestressed reinforced
concrete piles shall be used for design estimates, with a
bearing capacity limited to 25 tons and 50 tons respectively.
Excavation below the groundwater level will require dewatering,
which can be accomplished by using wells or well points.
11
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Existing Environmental Conditions
Diagonal Avenue Site Geology and, Soils
The Diagonal Avenue site is situated in the former
Duwamish slough meandering area. Before being filled, the
old slough channel bottom varied from approximately elevation
-7 to elevation 1. The slough bank was generally at elevation
4 to elevation 6. In developed areas, the ground surface is
raised by fill to about elevation 12.
Previous soil borings in the vicinity reveal that the
site is underlain by alluvial deposits over 100 feet thick.
The surface fill is generally dredged fine sands, ranging
from silty very fine sand to fine medium sand. Below the
surface fill, soft silty and peaty soils are found. Seis-
mic hazard risk is high for these soils. Piling will be
required for support of all structures at this site (Metro-
politan Engineers, Alki Facility Plan, 1977).
Groundwater was observed to be at elevation 2, but
fluctuates with tide. Dewatering is necessary if excava-
tion extends below the groundwater level.
Harbor Avenue S. W. Site Geology and Soils
The Harbor Avenue S.W. site is located to the east of
Harbor Avenue S.W. and to the west of the Duwamish West
Waterway, at the mouth of the Duwamish River adjacent to
the West Duwamish valley wall. Soil conditions at the site
vary depending upon the distance from the valley wall, the
nature of surface fill, and the meandering characteristics
of the Duwamish River.
Valley margin sediments of late Vashon and recent age
include sand, gravel and silt, deposited as slope wash
and/or with shells and wood in an intertidal zone. These
sediments are derived predominately from older reworked
deposits and, in general, immediately overlie eroded pre-
consolidated silt and clay, in relatively thin layers.
These sediments are generally medium dense or moderately
firm in consistency.
In general, it is believed that piling will be re-
quired for the support of all structural foundations. Soils
investigations will be necessary for the evaluation of
foundation supports at specific locations.
12
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Existing Environmental Conditions
Seismicity of Alternative Sites
As all of the alternative sites involve fill and some
high water table elevations, they carry a high seismic
hazard risk. Rasmussen et al., 1974, suggest that "one should
not build at this location unless the structure is specifically
designed to take into account substantial shaking and possible
soil failure." Since the entire downtown area of the City
of Seattle is built upon incongruous fills the placment of a
wastewater treatment facility on fill would not be an excep-
tional case.
Puget Sound Sediments Off Alki Point
The Puget Sound Interim Studies (PSIS) indicated
apparent changes in the organic content, grain size and
appearance of marine sediments in the characteristic plume
position for West Point (Harmon et al., 1976). As current
conditions and physiographic features at Alki are like those
at West Point, similar effects are assumed to occur. Both
West Point and Alki Point jut westward into the main basin
of Puget Sound and develop eddies to the north and south as
a result of tidal water movements (Duxbury, 1976).
Climate and Air Quality at Alki
With an average of 34.35 inches per year (1964-1972),
the Alki treatment plant experiences relatively low annual
rainfall compared to most of the Metro area. Refer to the
Regional Analysis for a more detailed discussion of climate.
Air masses flow in a southerly direction paralleling
the axis of Puget Sound from April to September, increasing
in average speed and reversing direction for the remainder
of the year. These conditions result in good ventilation
of the Alki service area. Air quality in the Alki service
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Existing Environmental Conditions
area tends to be somewhat better than in some of the more
confined airsheds within the Metro study area (e.g., Duwamish,
Interbay, Lake Union). Air masses which pass Alki Point have
been traveling a considerable distance over open water with
little topographical restriction. Ample mixing of this air
occurs as lateral mixing is unrestricted. The service area
is also insulated topographically from the industrialized
Duwamish airshed.
Odors at Alki
In Summer of 1976, the Puget Sound Air Pollution Control
Agency and Metro received complaints about offensive odors
generated by the Alki treatment plant. Almost immediately
Metro instituted remedial measures including increasing
chlorination, modifying the waste gas burner, adjusting the
boiler, and improving overall plant housekeeping. The odor
problem was apparently not overcome, as citizens of the service
area complained of odors at a public meeting in the Fall of
1976.
Plant odor continues to be locally noticeable, depend-
ing on wind direction, cloud cover, and similar factors. Area
residents state that odor is more noticeable at low tide, a
phenomenon with several possible simultaneous causes. Firstly,
the odor of wet tidelands (which may have anaerobic sediments)
is blown over the plant by southwest winds. Secondly, the
beaches at Alki are subject to a major combined sewer over-
flow (100+ mil gal/yr) containing raw sewage and street run-
off. The materials contained in this flow may settle in the
in tertidal or just subtidally to be uncovered by a low tide
although a local diver has seen no sign of deposition in this
area (DOE comment, 1977). Thirdly, the Alki outfall is judged
to be inadequate in having no diffuser section and discharging
into shallow water nearshore. Initial dilution is estimated
at 10:1. Examination of current and eddy patterns at Alki
suggests that effluents of low dilutions reach the shore as at
West Point but probably with greater frequency.
Climate and Air Quality in the Duwamish Valley
The Duwamish Valley extends north and south between 300-
foot high hills, opening onto Elliott Bay in the north and
the Green River Valley on the south. Low elevation mixing
air is confined by bordering hills and bluffs. Entrapment
occurs when the wind accumulates pollutant loads as it passes
over urbanized Seattle and then moves into the corridor,
where there is little or no air mixing because of the trap
14
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Existing Environmental Conditions
caused by the 300-foot high hills. Inversions occur frequently
in the Duwamish area.
For this corridor, different amounts of emissions are
found for northerly and southerly winds, because there are
different pollutant sources from each direction. When com-
pared with other sites, the Duwamish appears to receive the
most pollutants from outside its borders and generate the
most within its borders. It does not meet any of the standards
set by the Puget Sound Air Pollution Control Agency. Pollutant
concentrations in the Duwamish area are given in Table 2-1.
Water Resources
Water resources are described in terms of hydrographic
features, marine water quality and groundwaters.
Hydrographic Features
The principal hydrographic features in the Alki service
area are Elliott Bay to the north and central Puget Sound to
the west. There are approximately nine miles of marine shore-
line within the service area. In both Puget Sound and Elliott
Bay the bottom drops sharply to depths exceeding 300 feet,
generally within one-half mile of the beach. There are no
major freshwater bodies located within the service area.
Water Quality: Puget Sound Nearshore and Intertidal Waters
As indicated in the Regional Analysis and in the Puget
Sound Interim Study Report for the Municipality of Metro-
politan Seattle, the water quality of the central Puget Sound
basin is generally quite good. In the marine waters adjacent
to the Alki service area, however, there are two conditions
which could potentially adversely affect the quality of Puget
Sound waters, namely the inefficiency of the Alki treatment
plant outfall and the occurrence of periodic combined sewer
overflows (CSO's) along Alki and West Seattle beaches.
Outfall performance. The Alki Point outfall is 42
inches in diameter, extends some 1,300 feet offshore and
terminates as an open-ended pipe. It discharges wastewater
horizontally at a depth of about 80 feet. The operation of
the outfall is considered to be inefficient as a result of
15
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Existing Environmental Conditions
Table 2-1
Summary of Pollutant Concentrations
(Micrograms per Cubic Meter)
From Outside Generated Within
Service Area Service Area
Sulfur Dioxide
Duwamish 208 522
PSAPCA Standard:
230 for 24-hour
average
Nitrogen Dioxide
Duwamish 160 886
PSAPCA Standard:
100 for annual
average
Particulates
Duwamish 100 339
PSAPCA Standard:
150 for 24-hour
average
Hydrocarbons
Duwamish UKN 1,726
PSAPCA Standard:
160 for 3-hour
average
16
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Existing Environmental Conditions
poor initial dilution (10:1) and shallow discharge depth. An
oceanographic survey in the Summer of 1974 observed an effluent
bubble directly over the discharge point. Based on tidal
current patterns at Alki Point shown in the Puget Sound phy-
sical model, it is quite probable that effluent reaches the
shore with some regularity. Defining the extent of this
problem is complicated by the fact that Alki/West Seattle
waters also experience combined sewer overflows of some
magnitude and frequency during wet weather conditions. The
source of the fecal coliform bacterial levels exceeding State
shellfish production standards has, therefore, not been
identified. Annual overflow volumes are approximately
equivalent to half a day's flow from the Alki facility, how-
ever. The effects of the Alki outfall on other water quality
indices were barely measurable except for turbidity (Environ-
mental Quality Analysts, 1975). It has been demonstrated,
however (Smith, 1976),that substantial biological changes may
occur in the absence of measurable water quality alterations.
If the Alki plant continues to operate, improvements to the
outfall should be made, including extending the outfall into
deeper water and the addition of a diffuser section.
Combined sewer overflows. The Alki service area includes
many areas which are served by combined sewers; although
many of the area's sewers have been partially separated by
removing street drains, roof and yard drains are still
connected to sanitary sewers. As a consequence, the sewers
and pumping plants overflow along the shoreline area during
wet periods. The NPDES permit for the Alki service area
lists ten potential overflow locations (see Appendix C).
Annual volumes total about 5:5 million gallons, annual solid
loads, 5 tons, and BOD, 1.4 tons. The frequency and volume
of combined sewer overflows at these locations are quite
variable. While overflows have not been sampled in this
area, it is possible that the overflows which originate in
primarily residential areas may lack some of the toxic
elements which are introduced into the Duwamish via CSO's;
however, bacteria and virus contaminants from fecal matter
would be present. One of the largest overflows is at Alki
Point, which appears to empty directly onto the beach or
into nearshore water.
The effect of overflows on the marine environment de-
pends partially on the frequency and volume of the overflow.
Infrequent overflows of short duration would cause a tempor-
ary disturbance to the marine habitat with respect to BOD,
suspended soils, temperature, salinity and nutrients. Even
short duration overflows from residential areas may contain
heavy metals, toxicants and pesticides washed from the
streets, however, subjecting marine organisms to "shock
17
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Existing Environmental Conditions
loads" or "plugs" of untreated wastes which tend to persist.
The effects are minimized by efficient mixing. Frequent
overflows of long duration carry larger overall loads of
contaminants, although the waters may be more dilute.
Bacteria and viruses can increase in the receiving waters
to be filtered out and concentrated in shellfish and some
crustaceans to levels many times those in the water. The
intensive recreational shellfish harvesting use of Alki-
West Seattle beaches makes nearshore CSO's a serious
concern. No data were available during the facility plan-
ning study on the impact of Alki area overflows; however,
monitoring of offshore waters and shellfish is to occur in
1977. Data gathered at 40 of Metro's Puget Sound shoreline
monitoring stations in 1976 indicated that none of the near-
shore waters in the study area met state fecal coliform
standards for commercial shellfish, however. While health
warnings have not been posted, the Seattle-King County
Health Department discourages consumption of shellfish taken
from these beaches.
Eddy currents. The current regime in the immediate
vicinity of Alki Point probably works against efficient mix-
ing and rapid dilution of outfall effluent and overflows
when they do occur. Alki Point itself, much like West Point,
generates large eddies as tidal currents oscillate back and
forth along the north-south axis of the Sound. Past current
studies have shown that on an ebb tide, an eddy develops to
the north between Alki Point and Duwamish Head. On a flood
tide, eddies develop both north and south of the point.
Water masses more than 1,500 feet offshore do not seem to
be deflected by the point. Plotted travel times to shore
from various locations off Alki show that times to shore
from equal distances offshore are considerably greater for
locations southwest of the treatment plant site (observed
travel times ranged from 1 to 5 hours).
More recent studies using the Puget Sound physical model
show an additional eddy south of the point during major ebb
tides. Furthermore, it appears that horizontal mixing is
at a maximum during slack water periods when eddies predomi-
nate. Horizontal mixing is at a minimum during peak ebb
and flood periods when more uniform flow predominates. It is
during these periods that discharged effluent is most likely
to reach the beach. No information has been collected,
however, on the actual disposition of the Alki effluent.
The improvements to the outfall proposed in most of the
facilities planning alternatives should be preceded by studies
of the plume, the circulation in the vicinity and the biota in
areas reached by effluent. For more detailed discussion of
water quality and ecology for the central Puget Sound basin
18
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Existing Environmental Conditions
as a whole, refer to Chapter II of the Regional Analysis.
BIOTIC ENVIRONMENT
The habitats of interest in this document at the treat-
ment plant site and service area are suburban terrestrial
and park areas, and the waters of Puget Sound off the Alki
service area.
Terrestrial Ecology
As a fully-developed residential/commercial area, the
Alki service area has only limited value for wildlife.
Lawns, ornamental shrubs and trees, gardens,and small patches
of natural vegetation provide habitats for those species of
birds and small mammals which tolerate high levels of human
activity. Robins, sparrows, starlings and squirrels are
common in these areas.
The habitats are found in the large parks - Lincoln
Park and Schmitz Park - where a diversity of vegetation
encourages a wider variety of birds and small mammals.
The Alki treatment plant site itself is situated in a
residential area on the south shore of Alki Point. The
area has been extensively developed and vegetation is
limited to landscaping about the site, the ballfields to
the northeast and limited amounts of brush. As the diversity
of terrestrial animals correlates closelv with the diversity
of plants, these areas are expected to have little wildlife.
A more complete discussion of these effects and a list
of animals common in the Metro area is included in the
Regional Analysis which is Volume I of this series.
Marine Habitats
The waters off the Alki service area support communities
of invertebrates, finfish and marine plants. Figures 2-1
and 2-2 portray the types of intertidal and subtidal environ-
ments and representative biological communities found in the
marine waters adjacent to the Alki service area.
19
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Existing Environmental Conditions
Sandy Gravel Tidctend
Rott.nc T:rtr Defer it
High High Water
Common Fiih:
P,KifiC Salmon
S^'jtun T>nui
£>>.rvr & P.le FVch
SjnJ Lincci
Ounnrl
7^C *'
Fig. 2-1 Sandy Gravel Tideland
20
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Existing Environmental Conditions
Rock ind Cobble tidcbndl
Furpfl Short Ciah
Broken-Sack Shi imp
Common Fiih.
Rock Sol.
Cod'dt Ctberon
Smell
Sl.cilftv.ck
f'tx F.ih
leather
While or Staid**
O'antjc
S*i Cucumbe*-
Hiqh High W,itcr
mt«1
,^ V^ x' / Bluort w
•JC V^S / Mu"el PufullJ SuifrOi
OctODII
Fig. 2-2 Rock and Cobble Tideland
21
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Existing Environmental Conditions
In a Metro-sponsored study of five Puget Sound beaches,
investigators from the College of Fisheries at the University
of Washington identified 96 and 100 different species of
attached marine flora at Alki and Lincoln Park beaches,
respectively. Species diversity at these locations was
greater than at West Point (90 species), Richmond Beach (75),
and Carkeek Park (68) beaches. A survey of macrofauna (Chew
et al., 1976) identified 190 species at Alki Beach and 211
species at the control area in Lincoln Park in West Seattle.
These numbers differed little from those recorded at Carkeek
Park, West Point, and Richmond Beach. The diversity and
abundance of biota appear to indicate that Alki service
area beaches are generally healthy. Biota at sewer overflow
points has not been examined, however, nor have the levels
of toxicants they contain. It has also been suggested that
these beaches are merely equally stressed.
The beaches are popular clamming areas, with hardshell
clams and geoducks of particular interest. Washington
State Department of Fisheries sport shellfishing surveys
indicate that on an annual basis total user days for Alki-
West Seattle beaches is on the order of 7,250.
Of particular importance are the extensive eelgrass
beds which are found in the shallow waters off Alki. These
beds provide protection for Dungeness crabs as well as
important spawning and nursery grounds for herring and perch.
A small herring fishery located between Alki Point and
Duwamish Head supplies bait for the local sport salmon
fishery. Average annual production over the 1966-1970 period
was just under 46,000 pounds.
The biota in the waters off Alki and West Seattle has
long attracted the attention of divers and the area is one
of the most popular diving areas in the metropolitan Seattle
area. In some locations, wrecks have been sunk to provide
artificial substrates for invertebrates and to attract fish.
In 1971, a visual inspection of the Alki outfall and
immediate vicinity was made by submarine. The biota observed
appeared to be abundant and healthy. It should be noted,
however, that current disinfection practices result in
occasionally high levels of chlorine residuals in the efflu-
ent. According to an EPA report (Brungs, 1976), these resid-
uals may be toxic to a wide range of marine organisms at
very low levels. The effedts of such residuals upon the
biota near the Alki outfall are not known, although it may be
that the species of fishes and invertebrates observed repre-
sent more tolerant species. More detailed discussion of
effluent toxicity and disinfection is included in Chapter II
of the Regional Analysis.
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Existing Environmental Conditions
In a Metro-sponsored survey of demersal fishes in the
central Puget Sound basin, sixty-five .species were collected
off Alki Point using beach seines and otter trawl gear.
Species most frequently caught - 77 percent of eaten - using
beach seines were shiner perch, striped seaperch and tube-
snout. The abundance of adult and juvenile perch collected
suggest that the eelgrass beds serve as important nursery
areas for these species. Ratfish, striped seaperch, English
sole and rock sole accounted for nearly half (47 percent)
of the fish caught by otter trawl. Commercially valuable
side-striped shrimp were common at depths below 200 feet with
pink and coon-striped shrimp and spot prawns also present.
Nematode infestation (Philometra) of fish was generally
high throughout the year, ranging from 10 to 40 percent in
English sole and 3 to 18 percent in rock sole. Fish under
six inches in length were consistently free of nematodes.
There is no apparent relation between nematode infestation
and Metro outfalls, as high incidence rates were observed
along a north-south axis from West Point to Alki to Point
Pully and south. This phenomenon has been noted elsewhere.
Based upon small sample sizes, the incidence of tumor-bear-
ing fish was low. No evidence of fin erosion was observed
in the fish sampled.
NATURAL RESOURCES AND ENERGY
Natural resources and energy impacts are not analyzed
on a site-specific basis. Resources and energy consumption
occurs on an interrelated basis at the five existing Metro
plants and potential new sites. Rather, these considerations
are analyzed in the Regional Environmental Impact Statement
on an interrelated basis between the five existing Metro
plants and potential new sites.
THE HUMAN ENVIRONMENT
Many of the human environment facets pertinent to the
Alki site are discussed and evaluated only in the Regional
EIS. These include such categories as PSCOG goals and
policies and transportation patterns. Such topics can only
be analyzed on a regional basis by combining the four main
sites plus auxiliary sites (e.g., Cedar Hills sludge disposal
site). This necessity to treat certain topics on a regional
basis stems from the interrelatedness of the plants and the
trade-offs between alternatives.
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Existing Environmental Conditions
Site-specific impacts covered in this EIS are land
use; legal and institutional; agency and neighborhood goals;
social, recreational, and cultural; archeological and his-
torical; health and safety; aesthetics and nuisance.
Land Use
This description primarily concerns the Alki community
and service area and the Duwamish industrial and residential
districts.
The Alki community is a predominantly stable and nearly
completely developed residential area. Major recreational
areas include Schmidt Park, Alki Beach Park and the Schmidt
Viewpoint Park which serve local as well as other city resi-
dents. The community is beach oriented and will probably
continue to attract residents to the area because of this
association.
The City of Seattle has a Shorelines Management Program
and regulates shoreline uses. Anyone wishing to build a
structure exceeding $1,000 in cost or planning to alter
existing conditions in the shorelines area must obtain a
substantial development permit from the City of Seattle.
The Duwamish area contains some of the largest industries
in Seattle, including petroleum, cement, electricity and air-
craft industries.
Legal and Institutional
The legal and institutional elements considered include
shoreline management regulations, PL 92-500, and U.S. Army
Corps of Engineers permit regulations.
The City of Seattle/Shorelines Management Program has
been previously described. These regulations would nave a
direct effect on activities within 200 feet of the existing
shoreline. While not necessarily prohibiting expansion
activities, the shorelines program would control certain
aspects of such expansion.
Agency and Neighborhood Goals
Agency goals are described in depth in the Regional
EIS. They include the following:
24
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Existing Environmental Conditions
Puget Sound Council of Governments
The Puget Sound Council of Governments has proposed
the Interim Regional Development Plan, which states:
"Goal
It is in the public interest to minimize the
costs of future growth by encouraging new
development within urbanized areas where
necessary investments in public services have
already been made."
In further expanding on this goal the following policies
are included in the proposed document.
"1. Existing public utilities, facilities
and services shall be used to their
fullest prior to expansion.
3. Encourage conservation efforts and the
maximum utilization of utilities and
services before increasing supply.
5. The pattern of development which produces
the least cost in new public utilities,
facilities and services shall be encouraged
within feasible limits.
7. Plans for public services shall be consis-
tent with regional growth policies and
local comprehensive plans and shall be
based upon: 1) criteria for population
and employment distribution; 2) policies
designed to limit demand, 3) responsible
fiscal management."
Another goal of the PSCOG document related to natural
environment and amenities is the following :
"1. The natural beauty and liveability of this
region shall be a primary consideration in
the location, timing and quantity of growth.
a. Natural amenities identified as important
to the region1s character and beauty
shall be preserved or sensitively
developed as a second choice.
25
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Existing; Environmental Conditions-
b. Patterns of development which mini-
mize adverse impacts on these ameni-
ties shall be encouraged.
17. Permanent structures designed for human habita-
tion, commerce, employment or public assembly
should not be located within high risk zones,
including 100 yr floodways, earthquake zones,
or active landslide zones.
25. Achievement or maintenance of water quality
standards as established by law is recognized
and supported."
City of Seattle
As part of its general review authority, the City of
Seattle would review the construction of a sewage treatment
plant, rehabilitation of sewer lines or extension of sewage
facilities through its building department. Two permits
are required from the Seattle Building Department for the
construction of facilities, including one which examines
general design and construction and a second concerning
filling and grading activities.
King County
In 1964 King County adopted a comprehensive plan, cer-
tain provisions of this plan relate to the Metro Facility
Plan and are included as follows:
"Utilities Development Policies
Trunk utility lines should be installed in advance
or at the time of development in accordance with
the general plan for the area. Local or service
utility lines should be installed as needed.
Where pollution conditions now exist, all possible
steps should be taken to correct such conditions."
Goals for Seattle, a report prepared by the Citizens
of Seattle and adopted by the Mayor and the City Council
includes the following statements:
26
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Existing Environmental Conditions
"D. Goal: Water
The City should undertake all means reasonable and
feasible to ensure water purity to meet health
standards and protect the environment.
1. Undertake efforts to meet Federal Water Pollution
Control Act requirements by 1984.
a. It is the national goal that the discharge
of pollutants into the navigable waters be elim-
inated by 1985.
b. It is the national goal that wherever attain-
able, 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.
6. Ensure clean water to protect wildlife, vegetation
and recreation areas."
Citizen opinion surveys were conducted by HRPI through
Gerhardt Research in the Alki region.
When randomly chosen citizens were asked, in a Gerhardt
survey, what environmental concerns needed most attention,
most responded that they could think of none. Those who did
have an environmental concern mentioned such things as park
upkeep, heavy traffic on streets, noise or litter. Although
a few mentioned water quality, none directly pointed out any
of the wastewater treatment facilities as a serious
environmental problem.
Of the 370 people interviewed, most knew of the treatment
facility (about 84%), and it concerned a large number of
people (31%). When asked if they would favor upgrading sewer
treatment facilities as required by the law, the majority said
yes (59%). Most who opposed were concerned about cost,
necessity, unsightliness, the buying of private property, or
location of the facility. The highest number (52%) felt that
"cleaning up the environment" was more important than such
local issues as the site fitting in with the environmental
setting (15%) or the height of facility (11%). The considera-
tion of upgrading or expanding the facility was controversial.
HPRI (Metro's socioeconomic consultant for the EIS) and
Metro's community involvement staff conducted informal meetings
which were attended by citizens of the West Seattle area
explicitly concerned about the water treatment facility.
27
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Existing Environmental Conditions
In general, this group felt more strongly than those random-
ly interviewed by Gerhardt Research that Alki is not well
located. They felt that wastewater facilities should not be
in prime beach land, but rather in industrial regions. Resi-
dents said that unpleasant odors often occurred.
The Alki Community Council, in November, 1976, developed
the following guidelines, which "should not be construed as
precluding the addition of other criteria and concerns as
planning progresses."
"A. Closure of the present facility.
The present plant has never been considered
an adequately engineered facility, or constructed
for efficient operation when compared to more
modern plants. If it is economically and techni-
cally feasible, the unanimous vote of the com-
mittee was to close down the plant. The property,
including the Bar S playfields, should be re-
served for use as a park and recreation area
for the neighborhood and for Seattle residents.
This property should be evaluated for potential
usage as space for people a decade or more from
now, when the need for parks and open space may
be even more critical.
B. Expansion options for secondary treatment.
If the committee recommendation A is not feas-
ible, then the following criteria are essential:
1. There must be restrictions on the size, height,
and functions of any expanded or new facility.
These restrictions must be used to minimize ad-
verse effects upon the liveability of the surround-
ing neighborhoods.
2. There must be minimum sludge truck traffic in and
out of the facility. Access routes must not impact
the neighborhood, the traffic patterns, nor ad-
versely affect the environment.
3. There must be no odor.
4. Architectural and landscaping features must be
appropriate, approved by the community, and a
performance bond posted to guarantee that the
plans for these amenities will be fully imple-
mented as planned.
28
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Existing Environmental Conditions
5. There must be no further condemnation of resi-
dential property adjacent to or surrounding the
present facility.
6. There must be a clear and accurate breakdown of
the costs for the alternative options presented:
(a) constructions costs per householder;
(b) amount of increase in METRO use charges
per householder.
Cost breakdowns should also include the other 3
facility locations now being discussed (West
Point, Carkeek Park, Richmond Beach).
7. The Alki plant is adjacent to Seattle park property.
It is essential that expansion plans for the facil-
ity be evaluated for impact upon the beach and
park property. As the population in the area
increases and there is more intensive use of the
Alki recreation facilities and beaches by all
Seattle residents, there must be serious concern
for preserving these areas.
8. The sources of funds for construction/expansion
of plants at the 4 locations planned are of great
concern to the committee. After the experience
involved in the West Seattle Bridge controversy,
where funding was the weakest link, the committee
believes it would be irresponsible for any plans
to be approved until an accurate estimate of
costs can be provided to the public. The esti-
mate must be accomplished by a firm commitment
from federal, state, and/or other sources of
funds for the necessary construction.
9. The committee is deeply concerned that every
effort be made by METRO to evaluate technological
advances which may be available, rendering pre-
sent planning approaches either invalid or in-
adequate.
The Alki participants in workshop meetings were vocal,
and concerned about their desires being acted upon. They
wanted to convey that they are "good citizens" who have
been "good sports" about having a plant in their neighbor-
hood and that the agencies should carefully listen to them
since they have had to live with the plant.
Currently in the Duwamish area, data is being collect-ad
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Existing Environmental Conditions
on the sentiments of the people near the proposed plant
sites at Diagonal Way and Harbor Avenue S.W.
Economics and Costs
A description of cost determinations is developed
in the Regional EIS. In summary, costs, whether existing
or proposed, include three components: capital cost, operat-
ing and maintenance costs, and total annual costs.
The capital costs include the initial expenditures for
construction of wastewater treatment plants, sewage collec-
tion systems, effluent disposal methods, combined sewer
overflow facilities, sludge handling and disposal techniques,
plus the purchase of land and miscellaneous treatment-related
equipment. These capital costs typically are major expenses
that are made infrequently and that can be phased to suit
planning requirements. Because capital or construction costs
can require large sums of money at one time, they are often
financed by bonds or other types of loans that are paid
back with interest over a period of several years. The
yearly payment on the original capital cost debt is referred
to as the annual cost of capital or amortized cost.
Operation and maintenance costs include expenses such
as wages for labor, purchase of chemicals and power, and re-
placement or repair of equipment. These costs occur con-
tinually or at frequent intervals during the life of the
project.
The total annual cost of wastewater facilities is the
sum of the annual payment on amortized capital and the annual
operation and maintenance costs. The payment of total annual
costs can be achieved by various means, including charges
to persons who use the services.
Since user charges are determined regionally, they are
discussed in the Regional EIS.
Employment
Employment considerations are developed in the Regional
EIS.
30
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Existing Environmental Conditions
Social, Recreational and Cultural
Principal recreation resources within the service area
include Alki Beach Park, Schmitz Viewpoint Park, Loman Beach
Park, Lincoln Park and Schmitz Park. Except for Schmitz
Park all of these areas are in shoreline areas and support
both active and passive water-oriented activities. A major
factor in consideration of Alki expansion is the Bar S ball-
field northeast of the existing Alki treatment plant. This
ballfield is operated and maintained by the Seattle Depart-
ment of Parks and Recreation.
Cultural patterns in the Alki area are somewhat inde-
pendent of the Alki treatment facility and are considered
only to provide comprehensiveness to the EIS.
In the Duwamish area, data is still being collected.
Archeological and Historical
The Alki Light Station and Alki Beach are historical
sites near the Alki treatment plant ; however, these sites
would not be affected in any way by any of the alternatives.
With regard to archeologyt the Office of Public Archeology
states:
"Importantly, the Alki area owes its present topog-
raphy from past cut-and-fill operations. Because
of the intensive past disturbance of this site, we
would anticipate no adverse archeological impacts
associated with any proposed development." (Office
of Public Archeology)
An archeological site has recently been discovered
across the Duwamish River from the Diagonal Way site. The
Diagonal Way site should also be investigated before con-
struction.
No data are available on the Harbor Avenue site.
Health and Safety
Health and safety considerations include:
Occupational safety
31
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Existing Environmental Conditions
• Public health and safety related to the various
treatment facilities
• Existing health effects of combined sewer
overflows
• Sludge handling
• Various construction areas such as the storage
and transport of explosive or caustic chemicals
The Alki occupational safety record is generally in
compliance with all applicable regulations.
The public health and water quality implications of
sludge handling are described in the Sludge Management and
groundwater portions of the Regional EIS.
There have occasionally been slight health risks from
eating the shellfish collected along the shoreline close to
the Alki outfall, which is described in the biological sec-
tion of this EIS.
Aesthetics and Nuisance
The Alki treatment plant is generally well hidden from
view from most residents in the Alki service area. How-
ever, some residents in the immediate vicinity, particularly
those on surrounding bluffs, directly view the Alki plant.
While the plant is not particularly displeasing and many
of the plant components that would be most easily identi-
fied as part of a waste treatment plant are covered, the
plant still has an industrial appearance.
In addition, odor problems have been reported by resi-
dents in the past. Metro has recently installed propane
fired afterburners, which burn the excess gas coming off
the anaerobic digesters. This gas, often called "sewer gas"
contains methane, carbon dioxide, water vapor, and sulfides.
Some of it is used to warm the anaerobic digestion units;
some is used to run pumps, but excess is flared off. The
heat at which the sewer gas burns is not high enough to
oxidize the odorous compounds, but the temperature at which
propane burns in these afterburners is high enough to
oxidize many of the odorous compounds. These afterburners
cost $160/day to run. Even with the afterburners installed,
there still are complaints of odor problems from adjacent
neighbors. The anaerobic digester at Alki has a floating
cover; gases can leak out the sides. Also, primary
32
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Existing Environmental Conditions
clarifiers are in buildings but have openings to the out-
side air. This contributes to odor problems.
There are combined sewer overflows at Alki which cause
odor and visual nuisances.
The outfall for the Alki treatment plant is shallow
and short; it could allow odors, especially at low tide,
and it is debated that it causes sewage buildup in the sedi-
ments of this area.
For the Duwamish area, data are currently being collected
on aesthetics and nuisance. A wastewater facility may be
more compatible in an industrial area like the Duwamish than
in a residential area like Alki.
The roads which service the Alki treatment facility are
not paved and are considered dusty by local residents.
33
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34
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CHAPTER III
ALTERNATIVES AND IMPACTS
In this chapter, the alternatives and their impacts are
discussed in detail. The impacts of each alternative, both
primary and secondary, on the physical, biological and human
environments are discussed after a brief description of the
alternative. Other issues related to each alternative such
as mitigation measures and unavoidable adverse impacts are
also discussed. A general statement of the Facility Flan
objectives and the major issues involved, description of the
methodologies in selection of alternatives and flow and
waste reduction measures are also briefly discussed.
GENERAL
In order to assist in the selection of an environment-
ally sound and cost effective wastewater management alter-
native for Metro's service area and to encourage public in-
volvement in the selection process, the alternatives devel-
oped in the Draft Facility Plan (Metropolitan Engineers, 1977)
are described briefly in this chapter and evaluated in terms
of environmental impacts and relation to the planning
objectives of the study area. These objectives*as identified
in the Facility Plan,include: (1) provision of capacity
to serve the wastewater needs of the area through 2005;
(2) protection and/or enhancement of receiving water quality;
(3) adherence to the goals and/or legal requirements of
PL 92-500; (4) control of combined sewer overflows; and
(5) development of effluent and sludge re-use.
The environmental impacts of the alternatives discussed
in this chapter cover all of the elements of the environment
discussed in Chapter II. However, emphasis will be on the
following issues as related to Alki:
(1) The effects of alternative treatment processes (primary,
enhanced primary, and secondary) and combined sewer
overflow controls on water quality, aquatic ecosystems
35
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Alternatives and Impacts
and public health;
(2) Social, economic and public health effects of sludge
handling and disposal methods;
(3) The aesthetic, social and legal compatibility of the
alternatives with neighboring activities, land uses,
community goals, comprehensive plans and special codes;
(4) The identification of any groups which might bear an
undue portion of the costs in relation to the benefits
they receive;
(5) Control of odors at or near the plant;
(6) Elimination of combined sewer overflow to Alki Beach;
(7) Preservation of adjacent playing fields.
In addition to the discussion of the primary and second-
ary impacts of the alternatives, other issues pertaining to
each alternative such as unavoidable adverse impacts, meas-
ures that can be employed to mitigate the adverse impacts,
and irreversible and irretrievable commitment of resources
will be discussed for each alternative and compared to the
other alternatives.
DEVELOPMENT OF ALTERNATIVES FOR ALKI
The major issues addressed in the discussion of the
regional alternatives are pertinent in the selection of op-
tions available to the Alki plant. On the local level,
access, noise, traffic, visibility, odors, and the avail-
ability of land for expansion to secondary treatment are all
sensitive issues.
The role of the Alki plant in the Metro system has
been addressed in the Draft Facility Plan, particularly
as it relates to Alki site constraints and the regional
issues.
Alternative A is a no action alternative for Alki.
Alternative B, which represents no action pursuant to
PL 92-500, would include improving the Alki outfall.
Alternatives C and D address combined sewer overflows, but
would affect Alki differently. In Alternative C, the Alki
plant would be converted to enhanced primary, then abandoned,
and in 1995 its functions replaced by a new Duwamish plant
36
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Alternatives and Impacts
in wet weather and by transfer to West Point in dry weather.
In Alternative D, the Alki plant would provide enhanced prim-
ary treatment from 1985 to at least the end of the planning
period (2005). Alternatives E, G and H at Alki would upgrade
treatment to secondary as required by PL 92-500, but necessi-
tate expansion to the ballfield area. In Alternative F, Alki
would be abandoned in 1985, with its functions replaced by a
new plant in the Duwamish industrial area. A new outfall would
be constructed at Alki Point to discharge Duwamish plus Renton
flows.
The following section briefly describes considerations of
the Alki service area, treatment process, combined sewer over-
flows, effluent disposal method, sludge management, flow and
waste reduction measures and beneficial re-use of wastewater
at Alki.
Service Area
The service area for Alki treatment plants would remain
the same under all options due to the extent of development
in the area and the existing drainage pattern of the collec-
tion system. The proposed Duwamish plants would also serve
the Duwamish area and the southern portion of the West Point
service areas, in order to reduce flows and take into account
the site constraints at West Point or Alki.
Treatment Process
The alternative treatment processes for Alki are primary,
enhanced primary and secondary treatment. Primary treatment,
currently provided at Alki, is aimed at settling solids and
organic materials that would consume oxygen in the water to
which effluent would be discharged. Secondary treatment would
improve solids and organics removal to approximately 85 per-
cent and reduce metals, toxicants, bacteria and other con-
taminants in the discharge. Enhanced primary would be inter-
mediate in effectiveness. Secondary treatment is required by
PL 92-500. Alternatives which do not provide secondary treat-
ment are not in compliance with the current federal laws and
would not be eligible for state and federal funding unless
these laws and regulations are amended.
To comply with the secondary treatment requirement, addi-
tion of a biological process in one form or another to the
existing primary facility would be required. Processes con-
sidered were tower trickling filters, rotating biological
37
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Alternatives and Impacts
contactors and air activated sludge. These processes vary
in the amount of land required, energy and costs involved,
and various aesthetic impacts. Based upon results of pilot
plant studies and a comparison of environmental considera-
tions, performance and reliability, air activated sludge
has been recommended as the preferred process for upgrading
to secondary treatment. Reference is made to the Facility
Plan for further information.
Combined Sewer Overflows
Combined sewer overflows at Alki Beach currently discharge
5 million gallons per year at that site. Two alternatives
(C and F) would virtually eliminate CSO's there.
Effluent Disposal
Since the current outfall at Alki does not have diffusers
to adequately dilute the wastewater, the Draft Facility
Plan calls for improving the outfall for each alternative where
Alki remains. If a plant in the Duwamish were constructed,
new disposal facilities would be necessary.
Sludge Management
The Alki plant currently digests the solids or sludge that
settle in the primary treatment step. For alternatives that
add enhanced primary or secondary treatment, the solids
removed from the wastewater would increase, so expanded sludge
treatment facilities would be required. Other alternatives
include dewatering sludge to reduce its volume before hauling
to the Cedar Hills landfill. This would require installation
of dewatering equipment at Alki, but would reduce the frequency
of sludge truck trips through the neighborhood.
Flow and Waste Reduction Measures
,The measures considered for flow and waste reduction at
Alki were domestic water conservation and pretreatment.
38
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Alternatives and Impacts
Domestic Water Conservation
As discussed in the regional report, Volume I, the reduc-
tion in wastewater flows through adoption of domestic water
conservation and re-use measures is insignificant in a com-
bined service system with a high rate of infiltration/inflow.
This is clearly evidenced in the Alki collection system where
infiltration during wet weather conditions could be as high
as 5.8 mgd, which is almost double the base wastewater flow
generated from the area. Estimates of storm flows entering
the collection system could be up to 70 mgd which would be
20 times greater than the average dry weather sewage flow.
In addition, the implementation of domestic water conser-
vation measures by Metro is not feasible under the current
rate structure. To assure water conservation, local water
districts would be more effective. Alternatively, a Metro
rate structure which increased with higher flows to sewers
could be a possibility-
Due to the storm water flows and Metro rate structure,
water conservation was not considered in the Draft Facility
Plan for developing alternatives at Alki. For more on this
subject, the reader is referred to the Regional EIS.
Infiltration and Inflow
The characteristics of infiltration of groundwater into
the collection system and inflow from storm and roof drains at
Alki were examined to determine if flow could be reduced to
the plant. In compliance with PL 92-500, a detailed infiltra-
tion analysis was conducted on the Alki collection system
(Metropolitan Engineers, 1976). The analysis concluded that
although infiltration is high, especially during wet weather
conditions, it was not excessive and it would not be economi-
cal to remove it. Inflow into the collection system was also
examined. Since the system is a combined sewer system, storm
flows are appreciably high resulting in combined sewer over-
flow. Attempts to eliminate the inflow or appreciably reduce
it by separation or some other means would not be cost-effec-
tive. Therefore, efforts are directed towards control of the
combined sewer overflows. Various levels of control will be
discussed later in this chapter for the various wastewater
management alternatives considered. For more detail, the
Facility Plan or Alki infiltration/inflow study should be
consulted.
39
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Alternatives and Impacts
Pretreatment
Treatment to remove or reduce pollutants at their source
before they enter the common sewerage system is known as pre-
treatment. It can reduce mass pollutant loadings on facili-
ties and prevent the introduction of pollutants which might
disrupt the treatment process and contaminate the discharged
effluent or the waste residuals. Pretreatment efforts gen-
erally focus on industrial or commercial contributors of
pollutants. Since the Alki treatment plant does not receive
any industrial or commercial waste, pretreatment was not con-
sidered as a method in reducing flow or pollutant loading to
the plant.
For alternatives that include the Duwamish site, which
would include industries in the service area, pretreatment of
industrial flows to reduce pollutant loads should be consid-
ered further.
Beneficial Re-use of Reclaimed Water
As discussed in the regional report, it is highly un-
likely that any water reclamation would be justifiable in the
Seattle metropolitan area, where abundant local sources of
high quality water offer much greater potential at markedly
lower cost. As it applies specifically to the Alki service
area, the absence of industries and agricultural lands which
might use reclaimed water further diminishes the potential
for reclaimed water re-use. With the Duwamish sites, however,
location near industries may improve the potential for waste-
water reclamation and re-use.
REGIONAL ALTERNATIVES
The eight regional alternatives as described in the Draft
Facility Plan are described briefly to illustrate how Alki and
Duwamish facilities would fit into the Metro regional waste-
water system. Specific alternatives for the Alki service area
are described in the section following.
Eight alternatives on the regional level are being con-
sidered and evaluated by the 201 Facility Plan. These alter-
natives differ in the degree to which issues such as cost,
water quality, and compliance with federal and local policies
and goals are addressed. The regional alternatives consist of
one "no-action" alternative, one alternative which continues
40
-------
Alternatives and Impacts
unchanged the present comprehensive plan for the study area,
two which emphasize combined sewer overflow abatement with
minimal treatment upgrading, and four alternatives which
achieve secondary treatment with variations on combined sewer
overflow controls, site impacts, and re-use options. Alterna-
tives E through H are the only alternatives that comply with
the secondary treatment requirements of PL 92-500. The eight
alternatives are described below and are shown in Figure 3-1.
Alternative A - No Action
No capital expenditure would be made for expansion, modi-
fication or upgrading of treatment plants and no construction
of new interceptors during the planning period (until 2005).
Alternative A is evaluated to meet SEPA "no action" require-
ments.
Alternative B - Metro Comprehensive Plan
(No Action Pursuant to PL 92-500)
Plant upgrading and transfer interceptor construction
would be done according to the Metro Comprehensive Plan.
Alternative B is evaluated as the "no action" alternative
pursuant to PL 92-500 and NEPA requirements and serves as the
baseline for other alternatives. Puget Sound plants (West
Point, Alki, Carkeek Park and Richmond Beach) would be retained
with primary treatment. Improved sludge management and disin-
fection practices would be provided in Alternative B and all
following alternatives. Four new transfer interceptors and
improvements to the Alki outfall would be included.
Alternative C - Major Combined
Sewer Overflow Control
Major portions of combined sewer overflows would be con-
trolled by transfer from fresh to salt water and/or treatment.
The existing Puget Sound plants would be upgraded to provide
enhanced primary treatment by physical/chemical treatment of
solids during the summer. A new wet weather enhanced primary
treatment plant would be constructed in the lower Duwamish
industrial area and the Alki plant would be abandoned, both
in 1995.
41
-------
COMPREHENSIVE PLAM
(NO ACTION PURSUANT
TO PL 93-5001
MAJOR CSO CONTROL
PARTIAL CSO CONTROL
LEGEND
WEST POINT
DUWAMISH ISTORMWATERJ
OUWAMlSH (WASTEWATER)
RICHMOND BEACH
CARKEEK PARK
WEST POINT PHASE OUT
DE CONSOLIDATION
RECLAMATION
a -
ORTH LAKE SAMMAMISM
•
O
Metro 201 Facility Plan
Service Area Alternative'
-------
Alternatives and Impacts
Alternative D - Partial Combined
Sewer Overflow Control
Wet weather combined sewer overflows would be reduced to
Lake Washington, Lake Union and the West Seattle shoreline.
The four Puget Sound plants would be upgraded to enhanced
primary treatment with chemical addition during the summer
for improved solids removal.
Alternative E - Secondary
Secondary treatment would be added to the West Point,
Alki and Richmond Beach wastewater treatment plants by 1985.
The Carkeek Park plant would provide primary treatment for
wet weather flows only beginning in 1985; dry weather flows
would be pumped to West Point.
Alternative F - Secondary/Southern Strategy
Secondary treatment would be provided at Richmond Beach
and West Point (with a reduced service area). A major new
secondary treatment facility would be constructed in the
Duwamish industrial area in 1985; the Alki plant would be
abandoned at that time. A new outfall off Alki Point would be
built for discharging effluent from the Duwamish (and Renton)
plants. The Carkeek Par* plant would provide primary treat-
ment for wet weather flow only beginning in 1985; dry weather
flows would be pumped to West Point.
Alternative G - Secondary/West
Point Phaseout Option
Secondary treatment would be provided at the Alki and
Richmond Beach plants. West Point would continue as a primary
treatment plant for wet weather flows only, beginning in 1985.
A new secondary treatment plant in the Interbay area (Commo-
dore Way or Golf Park sites) would be constructed. The
Carkeek Park plant would provide primary treatment for wet
weather flows only beginning in 1985; dry weather flows would
be pumped to West Point.
43
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Alternatives and Impacts
Alternative H - Deconsolidation/Reclamation
Secondary treatment would be provided at West Point,
Alki, Carkeek Park and Richmond Beach. Areas of growth would
be served by new inland plants with local effluent and sludge
re-use possible. Advanced waste treatment would be provided
at new North and South Lake Sammamish plants. A new secondary
plant at Kenmore would discharge treated effluent to Puget
Sound.
Although there are eight regional alternatives, their
component parts could be blended to develop a hybrid alter-
native, as described in Volume I, Regional EIS.
A summary of information pertaining to the Alki treatment
plant alternatives is presented in Table 3-1. The plant site,
capacity, treatment process, and sludge management system are
outlined. More details are described in the following sec-
tions on each alternative.
44
-------
TABLE 3-1
SUMMARY OF ALTERNATIVES FOR 2005
ALKI AND DUWAMISH
(J\
A B
Sit* Alki Alki Alki
Blt* (Phase I)
Treatment Primary Primary Enhanced
Process ''isasT
C"?£irag« day/ 10/30 10/30 10/30
P*ak)
Disposal Site Existing Alki Improved Extended
(1966)
Sludge Digested at Alki; Digested at Digested at
Sanags^nt trucked to landfill "W^SS? *S i-Sflff
Facilities Hone Nona None
C
Alki
(Phase II)
Abandoned
(1995)
0/0
Outfall
None
Alki to
Duwamiah
(Heat Point)
Duwamiah
(Diagonal Hay)
Enhanced
•Primary
(1995)
0/250
Duwamiah
Solids transferred
to West Point for
Alki to
Duwaoish
(Heat Point)
D
Alki
Enhanced
Primary
(1985)
10/30
Extended
Hew sludge digester
and dewatering equip-
None
G, H
Alki
Secondary
(1983)
10/30
Alki
Hew aludge digester
and dewatering equip-
None
F
Alki Alki
(Phase I) (Phase 11}
Erinary Abandoned
(198S)
10/30 0/0
Alki To
Outfall Duwwlsh
Plant
Digested at
Alkij trucked Hone
to landfill
None Alki to
Duvaaish
DnwamisA
{Harbor Ave. S.V.)
Secondary
(1985)
45/145
Haw Ootf all at Alki
for DowOMish plo>
Ren ton effluent
Digested at Alkij
tracked to landfill
Alki to
Dmraalsh
rt
fl>
i-l
3
(D
rt
I-1-
<
(D
en
JU
13
&
H
•§
U
P
O
rt
CO
-------
Alternatives and Impacts
Alternative A
ALTERNATIVE A (NO ACTION)
General Description
In the No Action Alternative, the existing conditions at
Alki would be allowed to continue without any further expan-
sion or upgrading. The alternative serves as a tool for
planning additions and modifications to the existing facili-
ties by establishing the adequacy of such facilities and the
minimum requirements for their best performance.
The following sections describe the service area, collec-
tion system, wastewater treatment facility, and sludge manage-
ment system under existing conditions, which would be the
same as the No Action Alternative at Alki.
Service Area
The Alki wastewater treatment plant serves a residential
area of 4100 acres in the southwest corner of the City of
Seattle. The service area is bounded by Puget Sound on the
West, Elliott Bay on the north, approximately 35th Avenue S.W.
on the east, and by a line extending southwesterly from
36th S.W. and Foxbury to Puget Sound on the south (Figure 3-2).
The service area is primarily residential with a 1975 sewered
population of 44,000. There are no major industries in the
area with any significant wastewater discharge. There are
no major freshwater bodies within the Alki service area.
Under certain alternatives, the service area for Duwamish
would be considered. Because this area is presently part of
the West Point service area, its characteristics are described
in the West Point EIS document.
Collection System
The Alki system was originally constructed as a combined
sewer system. Since then the system has been partially
separated by connection of street drains to a new storm system.
However, roof drains and other inflow sources are still
connected to the old combined system.
The first city sewers were constructed in 1913, but
most were installed in the 1920's. Additional sewers were
installed as the area developed. Construction of the inter-
46
-------
T^/3-it'i:Wa
lwn!n=yji^
o .• * \. -A*. >-'»• D . ' / -; 4 '^\v*
.:"->,^..Ut4l xV
Figure 3-r2
Alki Point Service Area
47
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Alternatives and Impacts
Alternative A
ceptor sewers and force mains began in 1951 and was completed
in 1958. These interceptor sewers intercepted flows from
eleven combined sewer outfalls that had been discharging
raw sewage into Puget Sound, and conveyed the flows to the
treatment plant near Alki Point. Metro assumed control of
the interceptor system and treatment plant from the city
in 1962.
The Metro interceptor system consists of a series of
force mains, pressure sewers and gravity sewers which run
along the waterfront (Figure 3-2).
The sewers in the Alki service area are maintained by
the City of Seattle Sewer Utility Division. (In the past
10 years, 45% of the sewer system has been systematically
inspected. It is expected that the remaining portion will
be inspected in the coming 10-15 years-)
Adequacy of Alki collection system. Due to the age of
the collection system at Alki (much of it is about 50 years
old), cracked pipes and loose joints are expected; this
allows groundwater to infiltrate into the system. Combined
sewer overflows occur at all four Metro pumping stations in
the Alki service area. The wet weather flows tributary to
the pumping stations are far higher than their respective
capacities, most notably at the 63rd Street pumping station
at Alki Beach. The City of Seattle combined sewer system
also overflows to Puget Sound and Elliott Bay.
Wastewater Characteristics and Treatment Facility
The following sections describe briefly the wastewater
quantity and quality in the Alki area and the existing treat-
ment facility and its adequacy under the present- conditions.
Wastewater flows. Flow data collected for a three-year
period, 1973-1975, indicates that the monthly flow at the
Alki plant fluctuated between 4.1 and 13.1 million gallons
per day (mgd). Average flow during that period was 7.5 mgd.
The yearly average has increased by more than 8 percent since
1973. The sewered population would grow by filling in of
partially occupied areas. The increased population could be
handled by the plant's design capacity of 10 mgd. The peak
wet weather flow through Alki is restricted to its maximum
hydraulic capacity of 30 mgd.
48
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Alternatives and Impacts
Alternative A
Due to the combined sanitary and storm water collection
system, winter flows vary directly with rainfall; the wet
weather monthly average is over 2.5 times greater than the
dry weather flow. Since the flow to the plant is not by
gravity but rather is pumped from the 63rd Street pumping
station, the peak hourly flow is determined by the maximum
capacity of the pumping station. The station has a maximum
capacity of 50 mgd. Because of the hydraulic design of the
Alki treatment plant, maximum flow has been limited to 30 mgd.
All flow in excess of this figure bypasses to Puget Sound at
the 63rd Street pumping station.
Wastewater characteristics. In the Alki service area,
land use is primarily residential with some commercial activ-
ity- In addition, a major portion of the collection system
is a combined system and rather old. These conditions produce
a moderately concentrated sewage during the summer months and
weak-to-moderate sewage during wet weather conditions.
Physical and chemical indices that are commonly used
to define wastewater characteristics, treatment requirements
and performance and to assess the impact of the treated
effluent on receiving waters are BOD, COD, suspended solids,
nutrients and heavy metals.
Annual average five-day biochemical oxygen demand (BOD),
a measure of the oxygen demanding organic materials of influent
wastewater to the plant during the three-year period (1973-
1975), is 98 mg/1. This gives a monthly flow-weighted BOD
loading of 5,800 pounds per day. The highest recorded monthly
concentration was 147 mg/1 in June 1975; a BOD loading of
7,200 pounds per day. BOD concentrations vary inversely with
flow, so BOD loadings to the plant are variable throughout
the year.
The mean suspended solids concentration of the influent
stream over the three-year period is 120 mg/1. A peak monthly
value of 179 mg/1 was recorded in June 1975. Monthly flow-
weighted suspended solids loadings were 7,200 pounds per day.
Daily flow-weighted loadings should give a slightly lower
average loading. The suspended solids concentrations vary
inversely with flow because of effects of dilution; however,
it does not show characteristic seasonal variations. Based
on BOD and suspended solids characteristics of wastewater
influent to the plant, the flow is classified as weak to
medium strength sewage.
Detailed information is not available on the concentration
of metals in Alki influent. However, recent analysis of
effluent composite samples revealed the following concentrations
49
-------
Alternatives and Impacts
Alternative A
in mg/1:
Cd Cr Cu Hg Ni Pb Zn
0.004 0.01 0.04 0.0002 0.060 0.03 0.09
Data on nitrogen and phosphorus concentrations in the
Alki influent and effluent are not available.
Alki treatment plant. The Alki treatment plant is
located on a 2.8 acre site in the West Seattle area near the
Alki Point lighthouse. An aerial view of the site is shown
in Figure 1-2. The plant site is adjacent to a playground
and beach on Puget Sound and is surrounded by a residential
area. The site of the playground, although zoned for high
density residential development, is designated for recrea-
tional or park use by the City of Seattle Comprehensive Plan.
Metro holds a purchase option on the site for possible use
in plant expansion.
Sewage is pumped to the headworks of the plant from the
63rd Street pumping station. A high level overflow at the
headworks feeds into an automatic bypass line which connects
to the plant's outfall if flows exceed 30 mgd. Prechlorina-
tion, important in odor control, is provided at a manhole in
the headworks structure where a chlorine solution is supplied
to the influent flow via an open-ended pipe. Only manual
chlorination is available. After passing the headworks,
the wastewater travels through two flow measuring devices
and then enters the grit removal tanks where the grit is
removed and hauled away.
Raw settled sludge and floating materials are captured
in the primary sedimentation tanks and pumped to the primary
digester by means of a manually controlled sludge pump. The
effluent from the primary tanks enters a collection channel
which connects directly to a chlorine contact channel.
Chlorine is supplied by two 2,000 pounds per day gas
chlorinators. All chlorination equipment, including two
chlorine injectors, is located in the chlorinator room.
Each chlorinator can function either as a prechlorinator or
a postchlorinator. Injector water is obtained from the plant
spray water system which uses plant effluent. Chlorine
solution is conveyed by rubber-lined pipe to the point of
application at the inlet end of the chlorine contact channel.
Operation of the chlorinators is manually controlled; grab
samples from the chlorine contact channel are tested for
chlorine residuals and the results used as guidance for
manual control.
50
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Alternatives and Impacts
Alternative A
Effluent leaves the chlorine contact channel and dis-
charges to Puget Sound through a 42-inch diameter reinforced
concrete submarine outfall which terminates 1,300 feet off-
shore, at a depth of 79 feet, in an open-ended pipe.
Adequacy and reliability of the Alki treatment plant.
The Alki Point treatment plant was originally constructed in
1958 and has had several modifications. Currently, opera-
tional problems are experienced with the barminutors at the
headworks. Also, the pre-aeration units are limited in size
and cannot adequately treat the total flow pumped to the plant.
The pumping flow to the plant is erratic, and this affects
performance adversely. Measures to dampen such fluctuations
in flow would be required to achieve a consistently high
quality effluent, particularly with secondary treatment in
Alternatives E, G and H.
Adequate disinfection of the effluent cannot'be attained
under the present operating conditions. Chlorine feeding is
adjusted manually on a daily basis, rather than proportional
to the flow, resulting in varying dosage rate. A low dosage
rate would result in poor disinfection of the effluent, while
a high dosage rate would result in excessively high chlorine
residual. The chlorine contact time is partly accomplished
in the submarine outfall, and the detention time is inadequate
to accomplish the desired levels of disinfection at high
flows. The coliform count in the effluent cannot be monitored.
The operation of the outfall is considered to be
inefficient as a result of poor initial dilution and shallow
discharge depth. Effluent plumes directly over the discharge
point are noticeable, and diluted effluent apparently reaches
the shore regularly. If the Alki plant continues to operate,
improvements to the outfall will be necessary. These would'
include extending the outfall into deeper water and adding
a diffuser section.
The plant is provided with means for complete bypass of
the plant during emergency conditions. The plant is partially
bypassed when flows in excess of the plant peak capacity
occur during the rainy season. Control of combined sewer
overflows will reduce or eliminate such overflows, depending
on the level of control.
Odor control measures include prechlorination, post-
chlorination and burning waste digester gas in afterburners.
However, complaints from the neighborhood about odors are
still reported.
Since the plant provides primary treatment only, the
51
-------
Alternatives and Impacts
Alternative A
unit operations involved are rather simple to control and
operate and therefore can be considered reliable. Adequate
surveillance is also provided. The plant is manned seven
days a week, 14 hours a day during weekdays and 8 hours
during weekends. When unmanned, critical processes at the
plant are monitored at the main control center at West Point.
Standby power is available and comes on automatically in case
of a power failure, thus maintaining continuous operation
of the plant.
Sludge Characteristics and Management
The Alki sewage treatment plant has its own sludge
digestion facilities, but no sludge dewatering equipment.
Currently, digested sludge is hauled directly, in an unde-
watered form, to the Cedar Hills County landfill holding
basins, thus bypassing the West Point treatment plant entirely.
Impacts
Only primary impacts are considered in the site docu-
ments (Alki, Carkeek Park, Richmond Beach and West Point,
Draft EIS, Volume II). For information concerning secondary
impacts (Renton) please see the Regional Draft EIS, Volume I.
Geology, Soils and Topography
Because no site modifications are included, the No Action
Alternative would have no impact on slopes and soil stability,
erosion and deposition, topography and soil profile, or
shorelines.
Earthquake hazards to existing structures would continue.
Risks are moderate at this site based on soil type, but
limited in areal extent and of short duration. Structures on
fill, soft or loosely consolidated soils, are at greater risk
of long wave shaking; bedrock and well consolidated deposits
of short wave shaking.
The PSIS sampling near West Point found changes in the
organic content, grain size and chemistry of marine sediments
in the characteristic plume positions for this treatment
facility. As current conditions and physiographic features
of Alki are like those at West Point, similar effects are
assumed to occur including the probability of effluent
52
-------
Alternatives and Impacts
Alternative A
coming ashore during part of the tidal cycle.
Information on sediments off the Alki outfall is sparse,
Sedimentation rate is moderate and surface sediments show
a high (2.2) enrichment of lead in surface sediments of
unidentified origin.
Air Quality and Odors
All of the strateqies including No Action involve the
handling of chlorine and raw sewage. The alternatives also
require the operation of the sewage collection system in
which hydrogen sulfide, methane, and other products of
anaerobic decomposition commonly collect. All of them
involve the use of diesel and gasoline engines, both in
pumping and treatment plant operations and for routine trans-
portation and commuting. In high enough concentrations,
chlorine, sulfur dioxide, hydrogen sulfide, and methane can
be dangerous to human health. Chlorine and methane are also
explosive. The dangers from these gases are well known.
The existing treatment plant site is generally well
ventilated so that air emissions do not tend to concentrate,
though there is the possibility of entrapment against the
bluff. Odors, however, have been a recurring problem at
Alki. Complaints are received regularly. Since there are
no changes in the treatment plants under Alternative A, the
potential for odor problems at Alki would continue as at
present, causing moderately unpleasant conditions over a
limited area.
Water Quality
The No Action Alternative would retain the Alki Point
outfall as it exists now, even though that outfall is con-
sidered to be inefficient as a result of poor initial dilu-
tion and shallow discharge depth. No action would also main-
tain the hydraulic capacity of the Alki plant at a level
insufficient to treat all influent wastewater during wet
weather, so that CSO's would increase.
A decline in effluent quality would result as loadings
increase from growth in sewered areas. The volume and
frequency of CSO's would increase, continuing and increasing
water quality degradation. Public health concerns could
become increasingly important due to rising coliform bacterial
counts and viruses in nearshore waters and shellfish. In-
53
-------
Alternatives and Impacts
Alternative A
adequate dilution and disinfection are considered to have
some responsibility for nutrients, potentially toxic chlorine
residuals and coliform counts at Alki beaches. CSO's con-
tribute bacteria and nutrients as well, but are in addition
sources of heavy metals, pesticides, PCB's/and other chemi-
cals.
Biology
Terrestrial habitats. The No Action alternative is
expected to have no impact on terrestrial habitats, such as
urban, nonurban, forest and meadow lowland, as no construc-
tion is involved.
The intertidal. All beaches in the Alki service area are
accessible to the public. The PSIS dye studies have indicated
that at West Point, intertidal and nearshore organisms are
occasionally exposed to effluent at a dilution about half
that at the diffuser or 250:1. The frequency and distribution
of these events have not been determined. Changes in the inter-
tidal flora at West Point possibly attributable to effluent
nutrients have been described (Thorn et al., 1977). Based on
current patterns in central Puget Sound"^ as delineated by
the physical model, similar effects very likely occur regu-
larly at Alki due to effluent coming up on eastside beaches
during part of the tidal cycle.
Combined sewer overflows to Alki service area intertidal
occur at 7 points. West Seattle beaches receive a total of
about 5.5 million gallons annually. Limited sampling of biota
at the Denny Way overflow (Metro Staff, 1976) indicated a highly
disturbed situation reflected in low diversity and abundance
of organisms. The Denny overflow itself met water quality
criteria for receiving waters (EPA, 1975) for all parameters
except mercury. Copper and zinc were generally two or three
times higher in biota at Denny Way as in sediments. Mercury
was not measured at Denny Way and metals levels in biota at
other overflow points were not examined. In the absence of
data, the Alki overflows are assumed to be similar.
As overflows generally contain metals and toxicants which
do not degrade and are bioconcentrated, the overflows to West
Seattle beaches may possibly have minor to moderate adverse
long-term effects limited to certain intertidal areas and
generally irreversible.
Levels of trace metals in intertidal biota at outfall and
background areas were examined as part of the PSIS (Schell
54
-------
Alternatives and Impacts
Alternative A
et al., 1977) . Mercury in mussels and lead in all organisms
examined (a brown alga, a green alga, mussels and clams) were
higher at all outfall areas than at background areas (Point
No Point, Blake Island). Other trace heavy metals which were
higher at Metro outfall areas than at background areas were
cobalt in clams, zinc in clams and mussels, copper in clams,
chromium, selenium and cerium in mussels. The U.S. Food and
Drug Administration mercury standards for shellfish (0.5 ppm)
and the Canadian Food and Drug Directorate lead level of 2 ppm
net weight were not exceeded in any sample. Standards for
other metals have not been set.
Eelgrass beds which occur at Alki could be subject to
effluents brought up on the beach by tidal currents. West
Seattle beaches are also subject to combined sewer overflows,
as mentioned previously. While eelgrass beds are highly
productive and have a unique assemblage of plants and animals,
including the larvae of a number of fishes and crustaceans,
they tend to be in organic-rich sediments which may be anae-
robic just below the surface. Therefore, nutrients, BOD and
suspended solids from any source would probably affect them
but little. "Irreversible" contaminants such as metals,
toxicants or pesticides could however be incorporated into
organisms which become food for juvenile commercial herring,
flatfish, young salmon or waterfowl. The effect is presently
unknown but judged to be adverse, probably minor, limited in
extent to certain areas and long-term. Increased overflows in
the future could increase the magnitude of the effect.
Intertidal hardshell clams occur at Alki and West Seattle
beaches and at Lincfoln Park. Geoducks occur subtidally from
Alki Point to Point Pully. State standards for fecal coliforms
in shellfish waters were exceeded at all sites sampled in the
study area. Whether the coliforms are due to treatment plant
effluents, to sewer overflows or to septic tank seepage has
not been determined. Shellfish are not monitored for coliforms
in the study area at present. Thirteen species of "signifi-
cant" marine birds are recorded from Alki and from Point Pully
including loons, grebes, black brants, scoters, sandpipers,
and sanderlings (Salo,1975).
Puget Sound. The intertidal, nearshore subtidal, and.
offshore bottom, free-swimming and planktonic organisms off
the Alki service area are subject to effects of combined sewer
overflows, treatment plant effluent, runoff, septic tank
seepage, boat wastes and other pollutant sources. The inter-
tidal zone has been discussed previously.
Phytoplankton productivity is subject to effects of natu-
rally varying chemical and physical parameters. As a result,
55
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Alternatives and Impacts
Alternative A
it is almost impossible to detect the effects of treatment
plant effluent nutrients on the variation in algal population
size, and growth rates in time and space. Effects on zooplank-
ton are unknown.
Metals in plankton near outfall areas have been compared
to background areas (Point No Point) (Schell et al., 1977) and
to a sludge disposal site off Fourmile Rock in Elliott Bay.
Filter feeding zooplankton take in particles of the size on
which metals adsorb best. Zinc and copper were significantly
higher in plankton at outfall areas than at the control
station.
The distribution of some nearshore and offshore benthic
organisms (foraminifera, worms, clams, snails) appears to be
correlated with typical plume positions for West Point and
Carkeek Park effluents, for which•data are available, especi-
ally along the 150 foot contour. Studies on Alki have not
been performed but a similar effect of minor magnitude is
assumed to occur for the purposes of the impact analysis.
Nearshore free-swimming (nektonic) forms include juvenile
salmon, herring, and other commercial fishes that frequent the
outfall pipe, kelp, or eelgrass areas in the daytime or at
night. These animals could be occasionally exposed to levels
of chlorine and perhaps to other constituents at higher than
"safe" levels in effluent. Localized effects of effluents in
nearshore areas could affect herring populations directly or
through their zooplankton prey and thus affect salmon and
other organisms which feed heavily on herring in open waters
(Miller et. al., 1976) . While no data are available, it is
possible that~offshore nektonic organisms may also be occas-
ionally affected by chlorine, pathogens or toxicants if they
swim into or through effluent, or if they feed in nearshore
areas at night. Criteria for intermittent exposure of aquatic
organisms to total residual chlorine (.TRC) are time related.
For marine organisms, a concentration of 0.02 mg/1 for 100
minutes is a recommended criterion (Brungs, 1976; Mattice &
Zittel, 1977). Toxicity of Alki effluent has not been ex-
amined. Chlorine residuals at the West Point diffuser with a
190:1 dilution are at the borderline for chronic effects on
marine life with continuous exposure. The Alki outfall has
only a 10:1 dilution, so it appears that chlorine residuals
tne times higher than near West Point could exceed criteria
for chronic effects and will approach acute effects in waters
in the vicinity of the Alki plume at slack water. The poten-
tial effect on marine organisms is considered to be adverse,
minor-to-moderate, limited in extent in the waters, of short
duration (slacktide), and reversible.
56
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Alternatives and Impacts
Alternative A
Among the factors contributing to the present concern for
potential and environmental impact of chlorination is the for-
mation of halogenated organic compounds, specifically halo-
forms, in chlorinated effluents. The principal concern is
that the incorporation of a halogen (chlorine, bromine, iodine,
fluorine) into an organic molecule increases its attraction
to fats in animal tissue which usually results in increased
toxicity and bioaccumulation. There is a growing sentiment
that alternate forms of disinfection to chlorination be
emphasized to protect aquatic life. Recent studies (Marine
Research, 1976; R. K. Kawaratani, personal communication)
have shown that haloforms occur in approximately the same
concentrations after disinfection of power station cooling
water (saltwaters) with any of chlorine, bromine, ozone, or
hydrogen peroxide.
Commercial and sport fisheries. There are a number of
important sport and commercial fisheries within and adjacent
to the Alki service area. Those which occur in areas that
could potentially be impacted by treatment plant effluent
and/or sewer overflows are salmon (sport fishing in Elliott
Bay; commercial fishing south of Alki), herring (commercial
fishery from north Alki to Harbor Island), shrimp (fished in
Elliott Bay to Harbor Island), and crab (north and south of
Alki Point and at Lincoln Park).
The Duwamish estuary. The biota of the Duwamish (which
includes anadromous fishes discussed above)could be affected
by facilities plans at Alki that include a Duwamish secondary
plant discharging with Renton flows through the Alki outfall
ending Renton discharge to the Duwamish (Alternative F). The
biota of the estuary is discussed in the regional document
which is Volume I of this series.
Rare or endangered species and critical habitats. No
listed endangered species are recorded from the study area.
Critical habitats, which include salmon spawning and rearing
areas, fish migration routes and commercial fish areas and
waterfowl resting areas, have been discussed in previous
sections.
Natural Resources and Energy
Natural resources and energy impacts are not analyzed
on a site-specific basis. Rather, these considerations are
analyzed in the Regional Environmental Impact Statement on
an interrelated basis between the five existing Metro plants
57
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Alternatives and Impacts
Alternative A
and potential new sites,
The Human Environment
Many of the human environment facets pertinent to the
Alki site are discussed and evaluated only in the Regional
EIS. This includes such categories as PSCOG goals and
policies and transportation patterns. Such topics can only
be analyzed on a regional basis by combining the four main
sites plus auxiliary sites (such as Cedar Hills sludge dis-
posal site). This necessity to treat certain topics on a
regional basis stems from the interrelatedness of the plants
and the trade-offs between alternatives.
Land use. No new land would be used under Alternative
A. Current land use in a prime real estate area would con-
tinue. This is considered adverse, minor, long-term, local,
reversible and definite.
Legal and institutional. Many of the legal issues are
developed in the Regional EIS. This alternative does not
.fulfill the requirements of PL 92-500.
Agency and neighborhood goals. This alternative does
not fulfill the goals of the King County Comprehensive Plan
that "where pollution conditions now exist, all possible
steps should be taken to correct such conditions."
This alternative does not fulfill the goals of the Alki
Community Council that: "If it is economically and techni-
cally feasible, the unanimous vote of the committee is to
close down the Alki plant. The property, including the Bar
S playfields, should be reserved for use as park and recre-
ation area for the neighborhood and for Seattle residents."
Employment and costs. Employment and cost considera-
tions are developed in the Regional EIS.
Social, recreational and cultural. Under this alterna-
tive, the Bar S baseball diamonds would not be affected,
which is considered favorable, minor, long-term, reversible,
local and definite. However, degradation of the water near
the Alki outfall would continue with only primary treatment;
discouraging the recreational use of area beaches.
58
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Alternatives and Impacts
Alternative A
Archeological and historical. No known archeological
or registered historical sites would be affected by this
alternative/ because no construction is proposed.
Health and safety. There may continue to be health risks
associated with the consumption of raw shellfish due to the
discharge of effluent, as discussed in the biological section
of the EIS.
An unlikely safety hazard is accidental leakage of
chemicals when they are in transport or handled on site.
Although nearly every U.S. water and wastewater treatment
facility uses chemicals, there have been very few chemical-
related accidents.
The health and safety problems related to sludge trans-
port and disposal would be as probable as for any other trucks
in transit.
Aesthetics and nuisance. The Alki treatment facility
would continue to be a nuisance to local residents: it
would have an industrial appearance and could still be respon-
sible for odors. This impact would be adverse, major, long-
term, local, reversible and definite.
Under this alternative, 1.7 sludge trucks per day would
leave the Alki facility. These would cause some nuisance
on residential streets and some congestion along an already
crowded beach front, but the impact is considered minor.
Mitigation Measures
Because of the no action definition of Alternative A,
no mitigation measures can be proposed.
Unavoidable Adverse Impacts
All adverse impacts under Alternative A would be unavoid-
able. These would include impacts on water quality from CSO
discharge, related impacts on public health and fish, con-
tinued use of plant sites in parks or residential areas, and
violation of PL 92-500.
59
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Alternatives and Impacts.
Alternative B
ALTERNATIVE B METRO COMPREHENSIVE PLAN
NO ACTION PURSUANT TO PL 92-500
General Description
In this alternative, the policies and programs of the
Regional Comprehensive Plan conceived prior to the enactment
of PL 92-500 would be implemented. Metro's primary treatment
facilities would be expanded and upgraded primarily to accomo-
date growth resulting from Metro's present sewer expansion
policies.
The Alki service area, under this alternative, would
cover the same area tributary to the existing treatment plant
(Figure 3-1). Additional interceptors or pumping stations
would not be required. The increase in the sewered population
tributary to the system would result from filling in of parti-
ally occupied sewered areas. Additional sewering would be
limited mainly to service laterals. The treatment plant and
the tributary pumping stations will continue to receive more
wet weather flow than can be handled, and accordingly there
will be more combined sewer overflows. The additional popu-
lation could be served by the plant's present design capacity
of 10 mgd average and peak capacity of 30 mgd. Flows in
excess of the peak flow will be discharged to Puget Sound
untreated.
Under this alternative, primary treatment at Alki would
continue. Enlargement of the plant would not be required
since the projected flows for the planning period are within
the design capacity of the plant. Consequently, additional
site area will not be required. Improvements, however,
would be provided and would include additional chlorination
facilities and expansion of the pre-aeration and screening
facilities. The outfall would also be extended and diffusers
added to provide adequate mixing and prevent the effluent from
reaching the shore. The improvement cost is estimated at
$13 million. A layout of the plant site is shown in Figure
3-3 , which illustrates the location of improved chlorination,
pre-aeration and screening equipment.
Under this alternative provisions for additional sludge
handling facilities are not included. Sludge will be hauled
directly to Cedar Hills landfill for disposal.
Combined sewer overflows of 5 million gallons per year at
Alki Beach would continue as under existing conditions.
60
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Alternatives and Impacts
Alternative B
METRO-ALKI WASTEWATER TREATMENT PLANT
100 200
PRIMARY--UPGRADED
Figure 3-3
Alki Layout Alternative B
61
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Alternatives and Impacts
Alternative B
Impacts
Primary impacts only are discussed in this document;
secondary impacts are evaluated in the regional analysis.
Geology, Soils and Topography
Impacts would be as in Alternative A, except that
Alternative B (and C through H) assumes improvements to the
Alki outfall, in the form of extension of the outfall into
deeper water and addition of a diffuser section. Construction
would have a major but limited and probably short-term
adverse impact on benthic sediments and on light transmittance
in overlying waters. It is assumed that ultimately the
outfall could mean an improvement in nearshore and intertidal
sediments potentially affected formerly in a minor way by
effluent moving onshore as a result of tidal currents as at
West Point. Information on existing Alki sediments is
sparse. It is assumed that extending the outfall would
improve nearshore sediments and initiate some changes in
sediments further offshore near the new discharge point.
The negative effects are potentially minor, as the effluent
plume would be small, and limited in extent on the sediment
of Puget Sound.
Earthquake damage to the outfall line could result from
shock waves or from submarine landslides (if the strata are
arranged appropriately, which has not been determined).
A break in the line could allow effluent to boil up through
the opening. As this effect would have approximately the
same magnitude and probability of occurrence for all alterna-
tives, it has not been evaluated here.
Air Quality and Odors
All of the strategies including Alternative B involve
the handling of chlorine and raw sewage. The alternatives
also require the operation of the sewage collection system
in which hydrogen sulfide, methane and other products of
anaerobic decomposition commonly collect. All of them in-
volve the use of diesel and gasoline engines, both in pump-
ing and treatment plant operations and for routine transporta-
tion and commuting. In high enough concentrations, chlorine,
sulfur dioxide, hydrogen sulfide and methane can be dangerous
to human health. Chlorine and methane are also explosive.
62
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Alternatives and Impacts
Alternative B
^ existing treatment plant site is generally well
ventilated so that air emissions do not tend to concentrate,
though there is the possibility of entrapment against the
bluff. Odors have been a continuing problem at Alki. Com-
plaints are received regularly. Under Alternative B, the
odor problem would continue to cause moderately unpleasant
conditions over a limited area.
Water Quality
Primary effluent would continue to be discharged at
Alki, but through an extended and improved outfall. CSO's to
Elliott Bay would continue. Some minor improvements would
be made to the Alki chlorination facility.
Temperature, dissolved oxygen and salinity would be un-
affected. Nutrients would be reduced somewhat at the beaches
and nearshore by extension of the Alki outfall. Some nutri-
ents would continue at beaches due to CSO inputs. The net
adverse effect would be minor, because the contribution of
nutrients is not large; limited to Alki beaches; long-term,
because the discharges would continue through the planning
period; and reversible. The adverse impact from suspended
solids contribution is not large; limited to Alki beaches;
long-term because CSO's are intermittent but recurring; and
reversible.
Suspended solids inputs from CSO's would continue and
increase, continuing to have minor, limited, short-term
negative impacts. Coliform counts and chlorine toxicity
potential should be reduced by the new outfall, both near-
shore and at the beaches. Minor negative impacts from
chlorine could continue offshore. Coliforms would continue
to be moderate or high for short periods due to CSO's, both
on the beaches and nearshore.
Heavy metals, pesticides, and PCB inputs would be ex-
pected to continue at present levels in the absence of CSO
control.
Biology
Terrestrial habitats. Alternative B involves no site
expansions.
The intertidal. Elements of Alternative B which would
63
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Alternatives and Impacts
Alternative B
impact the intertidal are the extension and improvement of
the Alki outfall, increased flows and loads by 2005 of 22%
at Alki over 1976 levels, and continued sewer overflows
approximately at present rates. While impacts of nutrients,
pathogens and toxicants have not been examined in the biota
of Alki beaches, it is assumed that they occur based on
current patterns and the low dilution at the outfall.
Improvements to the Alki outfall would be expected to
reduce the nutrients, pathogens, solids and other parameters
that may affect intertidal biota. Increased algal biomass at
Alki could be due to nutrients being carried shoreward from
the outfall during part of the tidal cycle (R. Matsuda, per-
sonal communication, 1977). Also, the rocky substrate is
conducive to attached algae growths. The increase is diffi-
cult to quantify, however, as some species are harvested for
food. The effects on the kinds and numbers of clams are
equally difficult to assess for the same reason.
Surface tidal current patterns in central Puget Sound
indicate eddy systems forming north and south of Alki Point
and West Point. Dye studies at West Point indicate that inter-
tidal and nearshore organisms are occasionally exposed to
effluent at a dilution concentration about half that at the
diffuser, or 250:1. While no such studies were done at Alki,
based on the current patterns, the authors consider it highly
likely that effluent enters the intertidal zone at this site
as well, but with unknown frequency -
At Alki sewer overflows would continue at present levels
to 2005, Alki facility flows would increase 22%, and the Alki
outfall would be improved. The overflows contribute annually
the equivalent 0.1 to 0.2% of the flow from the Alki facility
(about half a day's flow), 0.5 - 0.6% of the solids and 0.1%
of the BOD. With respect to the intertidal, the improvement
of the outfall appears to be potentially more important than
the continued level of sewer overflows, although the overflows
contain essentially untreated wastes including metals and
toxicants. Metals are generally higher in intertidal biota near
outfall areas .
While coliform bacteria have not been measured in inter-
tidal shellfish, the overlying waters fail to meet state bac-
terial standards. As edible shellfish are dug near Alki, the
potential effects on public health of metals and pathogens are
a consideration. Eelgrass beds near Alki, which are important
feeding and breeding areas for commercial fishes and their
prey, could also be subject to effluent.
Nutrients, BOD and solids would probably slightly affect
these areas; any toxicants or pesticides could accumulate
64
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Alternatives and Impacts
Alternative B
affecting the fishes, their prey, and their predators. In
the absence of data on metals, toxicants and the frequency of
exposure to pollutants, the magnitude of the impact is un-
known .
Puget Sbund. The intertidal, nearshore subtidal, and off-
shore bottom,Iree-swimming and planktonic organisms in the
study area would continue to be subject to effects of combined
sewer overflows at present levels, increased flows and loads
from treatment plant effluents, plus runoff, septic tank
seepage, boat wastes, and other pollutant sources. The inter-
tidal zone has been discussed previously. The difference in
effects between Alternatives A and B are due primarily to the
improvement in the Alki outfall and increases in effluent flows
over 1975 levels. Improving the Alki outfall is not expected
to affect phytoplankton production at these flow volumes. No
effect on zooplankton has been determined, perhaps due to sam-
pling problems. In the absence of any data, the present effect
is judged to be unknown and future effects unpredictable.
Metals would probably remain higher in zooplankton near outfall
areas than at background areas, however (Schell et al., 1977).
The effects on the benthos identified in PSIS studies have
been correlated with the West Point plume position. Alki areas
were not sampled. The benthic conditions at this site are un-
known, but are probably similar, based on water circulation.
The potential adverse effect would continue, probably at
moderate levels, and limited on the bottom. The area affected
by the Alki plume would be transferred further offshore and
the area presently affected would probably return to a former
condition.
Nearshore free-swimming (nektonic) forms include juvenile
salmon, herring, and other commercial fish that frequent the
outfall pipe, kelp, or eelgrass areas in daytime or at night.
These animals could continue to be occasionally exposed to
levels of chlorine at higher than safe levels and perhaps to
other constituents in effluent.
Localized effects of increased effluents in nearshore
areas could affect herring populations directly or through
their zooplankton prey and thus affect salmon, and other
organisms which feed heavily on herring in open waters (Miller
et al., 1976) .
While no data are available, it is possible that offshore
nektonic organisms may also be occasionally affected by
chlorine, pathogens or toxicants if they swim into or through
effluent or if they feed in nearshore areas at night.
65
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Alternatives and Impacts
Alternative B
Criteria for intermittent exposure of aquatic organisms
to total residual chlorine (TRC) are time related. For marine
organisms, a concentration of 0.02 mg/1 for 100 minutes is
a recommended criterion (Brungs, 1976; Mattice & Zittel, 1977).
Alki effluent is chlorinated to a residual of 0.5 mg/1 and
diluted 10:1 at the outfall to 0.05 mg/1. This suggests that
organisms near the outfall could be exposed to higher than
safe levels of chlorine. The potential effect on these organ-
isms is considered to be adverse, minpr, limited in extent to
areas near the outfall, of short duration and reversible, even
with increased effluent flows and no improvement in chlorina-
tion facilities. With extension of the outfall and addition of
a diffuser.- the effect could be greatly reduced or eliminated.
Commercial and sport fisheries. There are a number of
important sport and commercial fisheries within and adjacent
to the Metro area. Those which occur in areas which could
potentially be impacted by treatment plant effluent and/or
sewer overflows are salmon (runs up the Duwamish; sport fish-
ing at Harbor Island, and in Elliott Bay; commercial fishing
south of Alki), herring, (commercial fishery from north Alki
to Harbor Island), steelhead (runs up the Duwamish), and shrimp
(fished in Elliott Bay to Harbor Island). The lower Duwamish
is crucial for the migration of juvenile salmonids. The poten-
tial for stress or contamination of these species is high. The
magnitude of the actual effect is unknown, but could be sub-
stantial .
The Duwamis'h estuary. The biota of the Duwamish (which
includes anadromous fishes discussed above) would continue to
be affected by CSO's at about present levels and Renton treat-
ment secondary effluent, at about 250% of present levels as well
as industrial inputs, runoff, etc. The ecology of the estuary
is discussed in the regional document which is Volume I of this
series.
Rare or endangered species and sensitive habitats. No
listed endangered species are recorded from the study area.
Critical habitats, which include salmon rearing areas, fish
migration routes, and waterfowl resting areas have been dis-
cussed in previous sections.
Natural Resources and Energy
Natural resources and energy impacts are not analyzed
on a site-specific basis. Rather, these considerations are
66
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Alternatives and Impacts
Alternative B
analyzed in the Regional Environmental Impact Statement on
an interrelated basis between the five existing Metro plants
and potential new sites.
The Human Environment
Many of the human environment facets pertinent to the
Alki site are discussed and evaluated only in the Regional
EIS. This necessity to treat certain topics on a regional
basis stems from the interrelatedness of the plants and the
trade-offs between alternatives.
Land use. No new land would be used under Alternative
B. Current land use in a prime real estate area would con-
tinue. This is considered adverse, minor, long-term, local,
reversible, and definite.
Legal and institutional. Legal issues are developed
in the Regional EIS. This alternative does not fulfill the
requirements of PL 92-500.
Agency and neighborhood goals. This alternative does
not fulfill the goals of the King County Comprehensive
Plan that "where pollution conditions now exist, all possi-
ble steps should be taken to correct such conditions."
This alternative does not fulfill the goals of the
Alki community council that: "If it is economically and
technically feasible, the unanimous vote of the committee
is to close down the Alki plant. The property, including
the Bar S playfields, should be reserved for use as park and
recreation area for the neighborhood and for Seattle residents."
Employment and costs. Employment and cost considerations
are developed in the Regional EIS.
Social, recreational and cultural. Under this alterna-
tive, the Bar S baseball diamonds would not be affected, which
is considered favorable, minor, long-term, reversible, local,
and definite. Degradation of the water near the Alki out-
fall would continue with only primary treatment. However,
since the outfall would be extended, the effect on water
quality would probably not be as great as it is now so
recreational usage of the Alki area beaches would not be
67
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Alternatives and Impacts
Alternative B
discouraged.
Archeological and historical. No known archeological
or registered historicalsites would be affected by this
alternative.
Health and safety. There may continue to be health
risks associated with the consumption of shellfish due to
the discharge of effluent, as discussed in the biological
section of the EIS.
An unlikely safety hazard is accidental leakage of
chemicals when they are in transport or handled on site.
Although nearly every U.S. water and wastewater treatment
facility uses chemicals, there have been very few chemical-
related accidents.
The health and safety problems related to sludge trans-
port and disposal would be as probable as for any other
trucks in transit.
With safety conscious procedures there should be a slim
chance of accidents during construction of the outfall.
Aesthetics and nuisance. The Alki treatment facility
would continue to be a nuisance to local residents: it would
still have an industrial appearance and could still be respon-
sible for odors. This impact would be adverse, major, long-
term, local, reversible, and definite.
Under this alternative, 1.7 sludge trucks per day would
leave the Alki facility. These would cause some nuisance
on residential streets and some congestion along an already
crowded beach front, but the impact is considered minor.
Mitigation Measures
While some odor-controlling measures have been imple-
mented, odor remains a problem at Alki. Odor-control is an
important and feasible mitigation measure for all alternatives
The costs of odor control are being calculated by Metro and
will be available by the end of July, 1977.
Visual impacts of the facilities, which are highly
visible by service area residents from above, could be miti-
gated by landscaping.
68
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Alternatives and Impacts
Alternative B
The energy and traffic impacts of additional sludge
truck trips co.uld be mitigated by the installation of dewater-
ing facilities to reduce sludge volume.
An improved chlorine feed system can be designed to
prevent chlorine levels in the sewage treatment plant efflu-
ent from exceeding toxic levels. This could be achieved by
matching chlorine levels to effluent discharge and/or intall-
ing a chlorine contact tank, which would maximize the effec-
tiveness of chlorination treatment. Currently, chlorine is
injected into the effluent flow at a constant rate calculated
daily. This causes a fluctuating chlorine residual.
Unavoidable Adverse Impacts
Under this alternative, the following adverse impacts
would be unavoidable.
Construction. Although construction activities can be
screened from public view, they will still be a temporary
nuisance.
Sludge trucking. Under current practices of disposing
sludge at remote sanitary landfill sites, there will necessar-
ily be sludge trucking.
Combined sewer overflows. This alternative does not
take adequate measure to control CSO's; they will still occur
in wet weather.
Primary effluent effect on water quality and biota.
This alternative does not implement secondary treatment; the
minor water quality degradation of Puget Sound would continue
as would effects on biota.
Noncompliance with PL 92-500. Public Law 92-500 requires
the installation of secondary treatment. This alternative
does not comply.
Land use. Land is required in all alternatives; the
question is: where will the impact occur?
69
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Alternatives and Impacts
Alternative B
Aesthetic nuisance of plant location. Wastewater treat-
ment facilities are a nuisance in all alternatives; the
question is: how can these nuisances be made smallest?
Operation and maintenance and capital costs. Construc-
tion of wastewater facilities, interceptors, and CSO holding
tanks is expensive. The facilities must be operated and
maintained.
Energy expenditures. Energy can in part be provided by
the methane produced in anaerobic digestion, but there is
still a large expenditure of energy which cannot be mitigated.
70
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Alternatives and Impacts
Alternative C
ALTERNATIVE C
MAJOR COMBINED SEWER OVERFLOW CONTROL
General Description
Alternative C is designed to control combined sewer over-
flows on the regional level. Overflows to Lake Washington,
Green Lake, Lake Union/Ship Canal, Alki Beach and the lower
Duwamish would decrease. However, CSO's to Elliott Bay would
increase.
For the Alki area, this alternative would involve
abandoning the Alki plant in 1995 and transferring its flow
to the new wet weather plant to be constructed in the
Duwamish industrial area.
The first phase Alki service area under this alternative
would be similar to the existing one. Collection system
modifications, however, would be required. The modification
would include enlargement of the existing 63rd Street pumping
station to pump a total flow of 70 mgd, a force main, and a
gravity system, possibly at the tunnel, to transport the flow
to both the Elliott Bay interceptor and the Duwamish wet
weather plant. Combined sewer overflows would be reduced
appreciably under this alternative. Five holding tanks would
be provided in the Alki/Duwamish area to store the flows in
excess of the collection system's and pumping stations' design
capacity. The following is a list of proposed collection
system improvements:
53rd Ave., SW pump station enlargement
53rd Ave., SW holding tank
SW Barton Street pump station revisions
SW Barton Street holding tank
Murray Avenue, SW pump station revisions
Murray Avenue, SW holding tank
Miscellaneous revisions - SW Dawson Street, etc.
63rd Avenue, SW pump station interim revisions
Combined sewer overflows would decrease to 0.15 million
gallons per year at Alki Beach.
71
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Alternatives and Impacts
Alternative C
The Duwamish wet weather plant is expected to be located
on Diagonal Way Avenue, but the site is not firm. It would
serve approximately 23,000 acres consisting of Alki and
southern portions of Elliott Bay and southwest Lake Washington
service areas. The majority of the sewers within these areas
are combined sewers; storm water in the Alki system is mainly
limited to roof drains.
The plant, by virtue of being a storm plant, would
operate on an intermittent basis and would be subject to
rapid increases and fluctuations in flow. A possible layout
of the plant is shown in Figure 3-4. The plant would provide
enhanced primary treatment for removing solids, metals, and
other related contaminants from those flows generated by the
Alki and southern West Point service areas. Disinfection
would be provided prior to discharge to the Duwamish through
a new outfall just south of the Harbor Island.
Solids settled from storm water would be stored on-site then
transferred to West Point via the interceptor system for
treatment.
Under this alternative, the Alki treatment plant would
be demolished and the site abandoned by 1995, as shown in
Figure 3-5. Dry weather flows from the Alki service area
would be treated at West Point, while the wet weather flows
would be treated at the new Duwamish wet weather plant at
the Diagonal Way site. Effluent would no longer be discharged
to Puget Sound and the outfall would be abandoned.
In the period from 1983 to 1995, the Alki plant would be
upgraded to enhanced primary treatment (as shown under
Alternative D) for improved solids removal. The capacity
would increase to 10 mgd average, 30 mgd peak due to a larger
sewered population. The outfall would be extended and im-
proved for better effluent dilution. Sludge would be digested
and dewatered by centrifuge at the site (see Figure 3-6),
then trucked to Cedar Hills landfill.
Impacts
Primary impacts only are discussed here; secondary im-
pacts are evaluated in the regional analysis.
Geology, Soils and Topography
Alternative C involves excavation for foundation con-
struction at the Duwamish site with eventual abandonment
72
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Alternatives and Impacts
Alternative C
METRO-DIAGONAL AVENUE SOUTH STORMWATER
TREATMENT PLANT (DUWAMISH)
EXISTING DUWAMISH
PUMPING STATION -
CHLORINE CONTACT CHANNEL
(IF REQUIRED)
SEDIMENTATION
OPERATION AND
MAINTENANCE BLDG
CHLORINATIpN AND SULFONATION
BLO&IIF REQUIRED
INFLUENT P
WET WEATHER PLANT - - PRIMARY
Figure 3-4
Duwamish Layout Alternative C
73
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Alternatives and Impacts
Alternative C
ABANDON
METRO - ALKI WASTEWATER TREATMENT PLANT
J'---^-'
Ji'T"1 u "JT 4g
Figure 3-5
Alki Layout Alternative C
74
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Alternatives and Impacts
Alternative C
of the Alki plant. The Duwamish sites are in areas of deep
alluvial or fil.l deposits and any structures erected there
would require piling and dewatering for foundation support.
Necessary pre-construction studies of local soil conditions
and the special precautions necessary to ensure stable
foundations would add to the duration and cost of construc-
tion. Such soils also carry the highest earthquake hazard
risks. The precautions necessary to deal with the above
hazards are well known. However, the impact of construction
waste debris on its disposal site could be adverse, and of
long duration, but minor and limited in extent.
Alternative C requires a tunnel under West Seattle and
the Duwamish River to transport sewage from the Alki site
to the new Duwamish wet weather treatment plant. Stability
is not expected to be a major problem in these glacial
deposits. However, there is some risk of reducing the
stability of the bluffs, particularly near the portals.
Disposal of muck from the tunnel excavation may pose a major
environmental problem depending on where this material is
taken.
Alternative C also includes construction of the Alki
connections to West Point expected to be completed in 1995.
Construction impacts in the form of increased erosion poten-
tial and subsequent deposition would probably be moderate, but
limited in extent to the area of the pipe and for the dur-
ation of construction. Additional soil and foundation
characteristics information would be developed .before con-
struction.
At Alki, the treatment plant would be eventually dis-
mantled (1995) and the site graded to the level of the
existing adjacent ballfield. This process would generate
dust, erosion potential, and construction waste (debris)
disposal concerns. Primary impacts are expected to be
minor, limited in extent, and of short duration at the
facility site.
Alternative C requires construction at Alki where bed-
rock is close to the surface. Construction at Alki may re-
quire heavy equipment or blasting to excavate for the founda-
tions. The strength of the bedrock is not well known, but
would be established through detailed site investigations
prior to commencement of construction. The excavation of
bedrock would affect topography, however, in a minor way.
Construction waste disposal could pose minor problems of
limited extent but long duration. Earthquake hazard would
continue at baseline levels. More sludge would be generated
in enhanced primary treatment from 1983 to 1995, but the
disposal site at Cedar Hills is expected to suffice on an
75
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Alternatives and Impacts
Alternative C
interim basis. Sludge disposal impacts are evaluated in
the regional analysis.
Information on Alki sediments is sparse. It is assumed
that improving the outfall (before abandonment in 1995)
would improve nearshore sediments and initiate some tempor-
ary changes (until 1995) in sediments further offshore near
the new discharge point. The negative effects are poten-
tially minor, as the effluent plume would be small and limited
in extent on Puget Sound sediment.
Overall, the impacts of C with respect to slope and
stability of foundations and earthquake damage potential are
major and adverse. Erosion and deposition problems are
considered to be minor, limited in extent, and of short
duration (less than five years). The effect on marine sedi-
ments of the improved outfall (used until 1995) and the
effects at the sludge disposal site would be as in Alternative
B.
Air Quality and Odors
Generally, the impacts on air quality under Alternative C
would be as for Alternative B except for the addition of con-
struction effects. The latter would occur 1) as dust at
Alki and Duwamish sites, increasing local particulates levels,
2) as emissions from the engines of heavy machinery. The
emissions to Duwamish area would be concentrated more as air
circulation is poor in the valley, which is subject to in-
versions. The contribution of the construction and operation
of the Duwamish plant, however, would be a tiny fraction of
the existing atmospheric pollutant load of the area.
Odors would be reduced at Alki due to the abandonment
of the plant, control of CSO's in the area and the extension
of the outfall. The potential for odors would increase in
the Duwamish on the site of the new facility. In general,
the odor problems now associated with Alki would be exacer-
bated by transferral to the Duwamish Valley which is subject
to poor air circulation, frequent temperature inversions,
and already high pollutant loads. The potential for odors
associated with the proposed holding tanks is discussed in
the Regional EIS.
Water Quality
Alternative C calls for abandonment of the Alki plant
76
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Alternatives and Impacts
Alternative C
in 1995, with construction of a new wet weather facility
in the Duwamish discharging primary effluent to the Duwamish
through a new outfall. Duwamish effluent would be chlorin-
ated. CSO control at Alki would be essentially complete
(97%), improving beach and nearshore water quality condi-
tions. The health risk associated with consumption of
shellfish from Alki would very probably be reduced. CSO
control will reduce the inputs of heavy metals and pesticides
to Alki waters, reducing the hazards of long-term bioaccumu-
lation of toxicants in fishes and other organisms. Heavy
metals would continue in the intertidal from direct runoff
and aerial fallout, however.
The Duwamish plant's construction could require exten-
sive dewatering, a problem judged to be minor and short-
term. The effect of discharge of chlorinated primary
effluent to the Duwamish is unknown at present.
The construction of the Alki outfall improvements would
entail excavation of bottom sediments, with resulting dis-
ruption of those sediments and increased turbidity in the
overlying waters. The effects are judged to be adverse and
moderate, but highly limited in extent, short-term and
reversible.
The interim improvements to the plant and outfall would
generally improve water quality. Extending the outfall
could prevent effluent from coming ashore (as is assumed,
based on currents similar to West Point where the phenomenon
is documented), which could reduce inputs of pathogens,
solids, metals, and toxicants to the intertidal. Chlorine
residuals concentration would be reduced through better
initial dilution achieved at the diffuser structure.
Groundwater levels would not be affected. Duwamish
water quality would be secondarily affected by the expansion
of the Renton treatment plant, as discussed in the Regional
EIS which is Volume I of this series.
Biology
Under Alternative C, Alki would be abandoned and a wet
weather plant constructed in the Duwamish by 1996. Discharge
of up to 250 mgd of wet weather primary effluent to the
Duwamish would stress resident biota, although the discharge
would be diluted. At the same time CSO to Elliott Bay
would increase 25 percent. Major CSO control would relieve
pressure on biota at Alki. Pathogens in shellfish at Alki
would be substantially reduced, probably due to CSO reduction
-------
Alternatives and Impacts
Alternative C
and extension of the Alki outfall. Flows and loads to Puget
Sound would increase at all plants except Alki which would
be abandoned.
Terrestrial habitats. The effects on terrestrial habi-
tats are expected to be negligible, as new facilities would
be in urban areas. Site impacts for the Duwamish plant are
expected to be negligible, as the sites occur in a highly
industrialized area of Seattle where terrestrial habitat is
minimal. Abandoning the Alki plant would be followed by
landscaping, thus increasing the terrestrial habitat avail-
able in the form of ornamental trees and lawns. The impact
would be positive, major, very limited in area, but long-
term.
The intertidal. Elements of Alternative C affecting the
intertidal area are a reduction in CSO's at Alki, increased
CSO's to Elliott Bay, increased effluent discharges from the
Alki outfall until 1995, when it is abandoned, upgrading of
Alki effluent to enhanced primary treatment levels, and
improvement of the Alki outfall until abandonment in 1995.
CSO's to Alki/West Seattle beaches would be almost elim-
inated (97% reduction), very probably reducing the amount of
metals, solids, BOD, nutrients, oil, grease, pathogens, and
toxicants impinging on biota and available for uptake and
concentration. Limited data available (at Denny Way) on
effects of a larger overflow of CSO to saltwaters indicate
adverse effects are moderate-to-severe,'limited in extent,
of long duration and probably irreversible for metals and
toxicants. The potential benefit of reduction of CSO's would
be moderate, also limited and long-term. Metals and toxicants
levels would stabilize in biota. Intertidal communities could
gain in abundance and diversity at sewer overflow points.
The Elliott Bay intertidal is considered to be far less
sensitive as much of it is highly disturbed urban waterfront.
While CSO's would become less important under Alternative C,
enhanced primary effluent flows would continue at Alki until
1995 when the plant is abandoned. The Alki outfall would simi-
larly be improved then abandoned in 1995.
In the interim, Alki would be upgraded to enhanced primary
treatment, allowing for some reduction in BOD, solids, metals,
and phosphates loads. The levels of nitrates would be as at
present however, and it is these nutrients that can become
limiting in the Sound. Assuming effluent enters the intertidal
occasionally, the potential enrichment effect of effluent would
continue at Alki but effects would be reduced or eliminated
with improvement and eventual abandonment of the outfall.
78
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Alternatives and Impacts
Alternative C
As chlorination facilities would be as presently operated,
overchlorinat.ion and underchlorination would be common. Under-
chlorination would probably maintain fecal coliform levels in
excess of state shellfish standards, and overchlorination could
produce chlorine residues toxic to intertidal and eelgrass bed
organisms. When Alki is abandoned, these effects would be
eliminated. With respect to solids, oil, grease and toxicants,
Alternative C would result in a moderate benefit to the inter-
tidal. With respect to potential chlorine, toxicants, nutrients,
metals and pathogens, there would be little change in or even
an increase over present levels of impact except, eventually, at
Alki.
Puget Sound. Effects on Elliott Bay and West Seattle
nearshore and offshore waters from Alternative C would be
from effluent plus the extension and abandonment of the Alki
outfall, and continuation of chlorination practices. Nutri-
ent loads would continue, with a similar increase in poten-
tial over-enrichment problems.
The distribution of some nearshore and offshore benthic
organisms appears to be correlated with characteristic plume
positions for West Point and Carkeek effluent. Similar
effects probably occur at Alki, but have not been examined.
Those effects connected to nutrient enhancement are assumed
to remain and those connected with solids or other loads
could decrease in magnitude until 1995 when the outfall is
abandoned.
Offshore and nearshore free-swimming organisms may con-
tinue to be occasionally affected if they swim into or
through an effluent patch, or if they feed in nearshore areas
at night. The effect is considered to be minor, limited in
extent to the plume area and of short duration as overchlor-
ination is short-term, but continuing.
The composition, diversity and abundance of fishes off
the Alki outfall could change as overall loads (except
nutrients) to the Sound through the outfall would decrease
with enhanced primary treatment.
With the abandonment of the Alki outfall .in 1995 the
effects of this point source would be eliminated probably
with benefits to the benthic nearshore and offshore environ-
ments. The pipe itself would continue to be attractive to
fish who feed on attached animals. Any metals or toxicants
in these organisms would probably remain.
79
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Alternatives and Impacts
Alternative C
Commercial and sport fisheries. Reducing sewer overflows
to the Duwamish and Elliott Bay would improve the quality of
these waters important as migration, spawning and rearing
areas to migrating salmonids and as sport fishing areas.
Reducing CSO's to Alki/West Seattle would benefit the herring
fishery associated with those areas.
At the same time, the new outfall to Elliott Bay (dis-
cussed previously) would threaten fish transition, migration,
and feeding areas.
The Duwamish estuary. Sewer overflows would be reduced
under Alternative C by about one-fourth. The effects of the
CSO control alone are considered to be a minor long-term
benefit to limited areas of the estuary ecological community
compared to the effects of the Renton facility, which would
greatly increase (see Regional EIS Volume I). The effect of
a new primary effluent discharge on the biota of the lower
Duwamish is unknown at this time, but discussed further in
the Regional EIS.
Rare and endangered species. No impact is expected as
no listed endangered species are recorded from the study area.
Sensitive habitats, which include salmon rearing areas, fish
migration routes, waterfowl resting areas, etc., have been
discussed in previous sections.
Natural Resources and Energy
Natural resources and energy impacts are not analyzed
on a site-specific basis. Rather, these considerations are
analyzed in the Regional Environmental Impact Statement on
an interrelated basis between the five existing Metro plants
and potential new sites.
The Human Environment
Many of the human environment facets pertinent to the
Alki site are discussed and evaluated only in the Regional
EIS. This necessity to treat certain topics on a regional
basis stems from the interrelatedness of the plants and
the trade-offs between alternatives.
80
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Alternatives and Impacts
Alternative C
Land use. At Alki, the facility would temporarily
be expanded to include enhanced primary- which would not
require the acquisition of new land; by 1995, the Alki facil-
ity would be abandoned, to be replaced by a wet weather en-
hanced primary treatment facility at the Diagonal Way site
on the Duwamish.
The eventual abandonment of the Alki site would be
favored in the Alki area. Data are being collected on the
response of Duwamish area residents to a wastewater facility
in their community.
Legal and institutional. Legal issues are developed
in the Regional EIS. This alternative does not fulfill the
requirements of PL 92-500.
Agency and neighborhood goals. This alternative
fulfills the goals of the Alki community council, that:
"If it is economically and technically feasible, the unani-
mous vote of the committee is to close down the Alki plant.
The property, including the Bar S playfields, should be re-
served for use as a park and recreation area for the neigh-
borhood and for Seattle residents."
This alternative also attempts to fulfill the priori-
ties set by the PSCOG that "natural amenities identified
as important to the region's character and beauty shall
be preserved or sensitively developed as a second choice" by
abandoning the Alki facility, which is on prime beach land,
but does not fulfill the same agency's goal that "existing
public utilities, facilities, and services shall be used to
their fullest prior to expansion," when the still-operable
Alki facility is abandoned.
Employment and costs. Employment and cost considera-
tions are developed in the Regional EIS.
Social, recreational and cultural. Under this alterna-
tive, the Bar S baseball diamonds would not be affected,
which is considered favorable, minor, long-term, reversible,
local, and definite. Further, the land which is currently
used for the wastewater treatment facility could eventually
be used for other recreational purposes.
81
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Alternatives and Impacts
Alternative C
Degradation of the water near the Alki outfall would
continue with only primary treatment; however, the outfall
would be extended into the Sound. Further, in this alter-
native, combined sewer overflows are controlled, improving
water quality. The net effect would be an improvement in
the water used for recreation. This impact is considered
favorable, minor, long-term, irreversible, local, and
probable.
Archeological and historical. No known archeological
or registered historical sites would be affected by this
alternative at Alki. An archeological site has recently
bean discovered across the Duwamish river from the Diagonal
Way site. The Diagonal Way site should be investigated
before construction.
Health and safety. There may continue to be health
risks associated with the consumption of shellfish due to
the discharge of effluent, as discussed in the biological
section of the EIS.
An unlikely safety hazard is accidental leakage of
chemicals when they are in transport or handled on site.
Although nearly every U.S. water and wastewater treatment
facility uses chemicals, there have been very few chemical-
related accidents.
The health and safety problems related to sludge trans-
port and disposal would be as probable as for any other
trucks in transit.
Construction safety risk would be as for any other
similar construction: with safety-conscious procedures
there should be little chance of accidents.
Aesthetics and nuisance. The Alki facility would be
phased out, eliminating a major nuisance in the Alki area,
but would be replaced in the Diagonal Way site; it is still
being determined how much of a nuisance the Diagonal Way
facility would be. Combined sewer overflows at Alki Point
and along the Duwamish River would be controlled, which
would remove much of their visual nuisance.
Under this alternative, 0.3 sludge truck per day would
leave the Duwamish site. This would cause some nuisance
on residential streets, but it is considered minor.
82
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Alternatives and Impacts
Alternative C
Mitigation Measures
While some odor-controlling measures have been imple-
mented at Alki, odor remains a problem. Odor control is an
important and feasible mitigation measure for this alterna-
tive until 1995 when the plant is abandoned. The costs of
interim odor control are being calculated by Metro and will
be available by the end of July, 1977.
Visual impacts of the facilities, which are highly
visible by service area residents from above, could be miti-
gated by landscaping.
The effects on water quality and biota from BOD, solids,
metals and toxicants identified or suggested for Alki/West
Seattle until 1995 and for the Duwamish estuary thereafter
could be reduced by employing enhanced primary treatment
year-round instead of just in summer, as presently proposed.
The data base for evaluation of impacts on the Duwamish
sites could be improved through thorough investigation of
soils and foundation characteristics, socioeconomic character-
istics and archeological sites.
An improved chlorine feed system can be designed to
prevent chlorine levels in the sewage treatment plant efflu-
ent from exceeding toxic levels. This could be achieved by
matching chlorine levels to effluent discharge and/or in-
stalling a chlorine contact tank, which would maximize the
effectiveness of chlorination treatment. Currently, chlorine
is injected into the effluent flow at a constant rate, calcu-
lated daily.
Further sites in the Duwamish area should be investigated
as possible alternatives to the Diagonal Way location.
Unavoidable Adverse Impacts
Under this alternative, the following adverse impacts
would be unavoidable.
Construction. Although construction activities can be
screened from public view, they will still be a temporary
nuisance.
83
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Alternatives and Impacts
Alternative C
Sludge trucking. Under current practices of disposing
sludge at remote sanitary landfill sites, there will
necessarily be sludge trucking.
Primary effluent effect on water quality and biota.
This alternative does not implement secondary treatment;
the minor water quality degradation of Puget Sound would
continue as would effects on biota.
Noncompliance with PL 92-500. Public Law 92-500 re-
quires the installation of secondary treatment. This alter-
native does not comply.
Land use. Land is required in all alternatives; the
question is:where will the impact occur?
Aesthetic nuisance of plant location. Wastewater treat-
ment facilities are a nuisance in all alternative^; the
question is: how can these nuisances be made smallest?
Operation and maintenance and capital costs. Construc-
tion of wastewater facilities, interceptors, and CSO holding
tanks is expensive. The facilities must be operated and
maintained.
Energy expenditures. Energy can in part be provided
by the methane produced in anaerobic digestion, but there
is still a large expenditure of energy which cannot be
mitigated.
84
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Alternatives and Impacts
Alternative D
ALTERNATIVE D
PARTIAL COMBINED SEWER OVERFLOW CONTROL
General Description
Similar to Alternative C, Alternative D is designed to
reduce the combined sewer overflows to all receiving waters
during the planning period, with priority given to the most
sensitive use areas, specifically the inland waters. The
Alki service area overflows would be reduced by provision
of holding tanks for combined sewer overflows and additional
transfer systems. A holding tank at Murray Avenue and other
miscellaneous revisions to the collection system will be
provided. The combined sewer overflows at Alki Beach would
be 4.47 million gallons per year, more than Alternative C
but less than Alternative B.
The Alki service area would remain as it exists
currently, but the additional sewered population would produce
10 mgd average, 30 mgd peak flow to the plant.
Under this alternative, the Alki treatment plant would
be upgraded to enhanced primary treatment in 1985 and would
include chlorination facilities, pre-aeration and screening
facilities, chemical feeding and storage, and sludge handling
expansion with a digester and centrifuge, shown in Figure 3-6
With the exception of the new digester, the site would change
little in appearance and the site area would be sufficient
to accomodate the improvements.
The treatment process would be upgraded to enhance the
BOD and suspended solids removal efficiencies during summer
months only. Treated wastewater would be discharged through
the Alki outfall, scheduled for major improvements.
The additional solids loads from growth and enhanced
primary treatment would require a new anaerobic sludge
digester. To reduce the volume of sludge and resulting sludge
truck traffic, the sludge would be dewatered by centrifuge
before being hauled to the Cedar Hills landfill site for
disposal.
The expansion and modification of the treatment facili-
ties would be located on the present site and, therefore,
additional land will not be required. The construction cost
is estimated at $15 million. The service area and collec-
tion system under this alternative are similar to those
under present conditions.
85
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Alternatives and Impacts
Alternative D
METRO-ALKI WflSTEWATER TREATMENT PLANT
ENHANCED PRIMARY
Figure 3-6
Alki Layout Alternative D
86
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Alternatives and Impacts
Alternative C
Impacts
Primary impacts only are discussed here; secondary im-
pacts are evaluated in the Regional Analysis.
Geology, Soils and Topography
Alternative D requires construction of enhanced primary
at Alki v/here bedrock is close to the surface. No plant would
be built in the Duwamish, and no shoreline fill would be
required. Construction at Alki may require heavy equipment or
blastrhg to excavate for the foundations. The strength of the
bedrock is not well known, but would be established through
detailed site investigations prior to commencement of con-
struction. The excavation of bedrock would affect topography,
however, in a minor but irreversible way. Construction waste
disposal could pose minor problems of limited extent but long
duration. Earthquake hazards continue as in baseline condi-
tions. More sludge would be generated by enhanced primary
treatment, but the disposal site at Cedar Hills is expected
to suffice on an interim basis. Sludge disposal impacts are
evaluated in the regional analysis.
Outfall construction would have a major but limited and
probably short-term and reversible adverse impacts on benthic
sediments and on light transmittance in overlying waters.
Information on existing Alki sediments is sparse. It is
assumed that extending the outfall would improve nearshore
sediments and initiate some changes in sediments in addi-
tion to those from construction further offshore near the
new discharge point. The negative effects are potentially
minor, as the effluent plume would be small, and limited
in extent on the sediment of Puget Sound.
Earthquake damage to the outfall line could result
from shock waves or from submarine landslides (if the strata
are arranged appropriately which has not been determined).
A break in the line would allow effluent to boil up through
the opening. As this effect would have approximately the
same magnitude and probability of occurrence for all alterna-
tives, it has not been further evaluated here.
Overall, the impacts of Alternative D with respect to
slope and stability of foundations and earthquake potential
damage are major and adverse. Erosion and deposition prob-
lems are considered to be minor, limited in extent, and of
short duration (less than five years) and reversible. The
effect on marine sediments of the improved outfall and the
87
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Alternatives and Impacts
Alternative D
effects at the sludge disposal site would be as in Alterna-
tive B.
Air Quality and Odors.
All of the strategies including Alternative D involve
the handling of chlorine and raw sewage. The alternatives
also require the operation of the sewage collection system in
which hydrogen sulfide, methane and other products of anaero-
bic decomposition commonly collect. All of them involve the
use of diesel and gasoline engines, both in pumping and treat-
ment plant operations and for routine transportation and
commuting. In high enough concentrations, chlorine, sulfur
dioxide, hydrogen sulfide, and methane can be dangerous to
human health. Chlorine and methane are also explosive. The
dangers from these gases are well known.
Odors at the Alki plant have been a recurring problem.
Extension of the Alki outfall would improve odors somewhat,
as would controlling combined sewer overflows in the service
area. The pollutant load reduction at the Alki overflow
would be only 18%. Odors at the plant, then, would persist,
causing moderately unpleasant conditions over a limited area.
Construction would generate dust, temporarily increas-
ing the ambient particulates level, and emissions from
machinery and equipment would temporarily raise local air
pollution levels.
The potential odor problems associated with the proposed
holding tanks are discussed in the Regional EIS.
Water Quality
Under Alternative D, primary treatment at Alki would
be enhanced by alum addition in summer for greater solids re-
moval (22%). An 18% reduction would occur in combined sewer
overflows to the Alki area (Metropolitan Engineers, 1977).
The Alki outfall would be extended.
No impact is expected on temperature, DO, salinity or
BOD at beaches, nearshore or offshore. Nutrients and patho-
gens entering the intertidal would probably be improved by
extending the outfall. The adverse impacts of nutrients
from remaining CSO's would probably be minor, because the
discharge is not large; limited to Alki/West Seattle beaches;
long-term, because the discharge would continue through the
88
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Alternatives and Impacts
Alternative D
planning period; and reversible. Enhanced primary treat-
ment alone would have little benefit with respect to nutri-
ents, as phosphates are apparently never limiting and nitrates
are not removed. The impact from suspended solids along
beaches would continue through the planning period; and
reversible.
At the beaches, coliform levels should be lower in
summer as CSO's are rarer then, and the outfall would be ex-
tended. Remaining coliform problems at beaches would prob-
ably be minor, limited in extent, but long-term. Coliforms
offshore and nearshore would be greatly reduced.
Heavy metals and toxicants inputs would also be reduced
to a minor-to-moderate extent by alum addition to effluent
and some overflow control. The impact is judged to be posi-
tive and minor, but long-term.
Risk of toxic chlorine residuals nearshore would be
reduced by extending the outfall and addition of a diffuser
section to improve initial dilution.
Outfall construction would entail excavation of marine
sediments, with resulting increased turbidity in the over-
lying waters and resuspension of metals and toxicants. The
effects are judged to be adverse and moderate, but highly
limited in extent, short-term and reversible.
Primary impacts on groundwater levels, Duwamish water
quality and Elliott Bay water quality would be the same as
under Alternative B. Secondary impacts on Duwamish water
quality from the expansion of Renton are discussed in the
Regional EIS which is Volume I of this series.
Biology
Implementation of Alternative D would include an 18%
decrease in CSO's to West Seattle. CSO's to Elliott Bay
would increase 21 percent relative to Alternative B. The
Duwamish flows would continue at baseline (B) levels, but
loads of BOD and solids would decrease by 24 and 29 percent,
respective to Alternative B, due to the installation of
enhanced primary treatment at Alki. The Alki outfall would
be improved.
Terrestrial habitats. Impacts are expected to be negli-
gible, as construction would impact only marginal habitats.
If landscaped, impacts on-site could be positive as shrubs
89
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Alternatives and Impacts
Alternative D
and trees would provide new habitats for wildlife.
The intertidal. Intertidal organisms would be affected
by continued effluent nutrient loads and perhaps pathogens.
Loads of BOD and solids and perhaps metals would be reduced.
Overflows at Puget Sound would be reduced 18 percent at West
Seattle, but would increase 21 percent at Elliott Bay, rela-
tive to Alternative B. The Alki outfall would be improved,
reducing substantially the potential for effluent affecting
the intertidal.
Continued nutrient (nitrogen) loads would maintain
probable enrichment effects on intertidal algae and algae
grazers.
Metals levels at the outfall area could continue to be
higher than at background stations (Point No Point), since
chemical precipitation would be employed only in summer.
Metals removal with enhanced primary treatment is somewhat
but not consistently better than with primary.
Pathogens could continue to reach the -intertidal through
CSO's and effluent coming ashore, probably maintaining bac-
terial levels that exceed state shellfish standards. The
design of the extension of the Alki outfall could probably
prevent effluent from coming up on the beach, as is highly
likely at present. Eelgrass beds would also be benefited
by the extension of the Alki outfall and somewhat by summer
chemical precipitation treatment of Alki effluent.
Puget Sound. Nearshore and offshore life are affected
more by effluents than by overflows which disperse along
shore. The Alki outfall would be extended and improved.
The extended Alki outfall would place the effluent closer to
mid-channel where major algae blooms develop. It is not
known whether or not any new effects would occur as a result.
The distribution of some nearshore and offshore benthic
organisms appears to be correlated with the characteristic
plume positions for West Point and Carkeek effluents. Simi-
lar effects probably occur at Alki, but have not been
examined. Those effects connected with nutrient enrichment
are assumed to continue and those connected with solids and
other loadings to decrease in magnitude with enhanced
primary treatment.
Offshore free-swimming organisms may continue to be
affected by effluents if they swim into or through an efflu-
ent patch, congregate around the outfall, or feed in near-
90
-------
Alternatives and Impacts
Alternative D
shore areas at night. The effect at Alki is unknown, but is
potentially minor, limited in extent to the plume dispersion,
of short duration and reversible except for metals and
toxicants.
The composition, diversity and abundance of fishes off
the^Alki outfall could probably change as overall BOD and
solids loads to the Sound through the outfall would decrease
with enhanced primary treatment.
Continuation of present chlarination practices, i.e.
constant daily feed rate regardless of hourly effluent flow
rate, tends to result in overchlorination and/or underchlor-
ination. At Alki the initial dilution of the effluent is
10:1, which is not sufficient to dilute 0.5 mg/1 chlorine
residual (average) to safe levels (0.02 mg/1; Brungs, 1976).
With the extension of the outfall and addition of a diffuser
structure the effect is expected to be greatly reduced or
eliminated.
Commercial and sport fisheries. Herring fisheries at
West Seattle would be slightly benefited by the 18% decrease
in CSO's, metals, toxicants, oil and grease to eelgrass bed
areas. The salmon and trout runs up the Duwamish through
Elliott Bay, however, would continue to be potentially
threatened by overflows at present levels from BOD, solids,
metals, and toxicants. Sport shellfish would probably
continue to be a potential health risk as fecal coliforms in
the waters exceed state shellfish standards. Effects on
juveniles of commercial species that feed in nearshore areas
potentially affected by effluents would be unchanged from
present except that eelgrass beds would be less affected.
The above effects are considered to be reversible, ex
tensive on the fisheries, and of long duration.
The Duwamish estuary. Annual volumes of sewer overflows
to the Duwamish would remain at about baseline levels under
Alternative D. The ecology of the Duwamish is discussed in
the Regional EIS.
Rare and endangered species. No impacts are anticipated
under Alternative D for rare species as none are recorded
from the study area. Critical habitats such as salmon rear-
ing and migration areas, and waterfowl areas have been dis-
cussed previously.
91
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Alternatives and Impacts
Alternative D
Natural Resources and Energy
Natural resources and energy impacts are not analyzed
on a site-specific basis. Rather, these considerations are
analyzed in the Regional Environmental Impact Statement on
an interrelated basis between the five existing Metro plants
and potential new sites.
The Human Environment
Many of the human environment facets pertinent to the
Alki site are discussed and evaluated only in the Regional
EIS. This necessity to treat certain topics on a regional
basis stems from the interrelatedness of the plants and
the trade-offs between alternatives.
Land use. Under Alternative D, the addition of en-
hanced primary treatment would only require land space for
a couple of additional tanks. This space is already avail-
able on the current facility site; no new space would be
required.
Legal and institutional. Legal issues are developed
in the Regional EIS. This alternative does not fulfill the
requirements of PL 92-500.
Agency and neighborhood goals. This alternative ful-
fills the goal stated by the PSCOG that "existing public
utilities, facilities, and services shall be used to their
fullest prior to expansion" but does not fulfill the goals
of the King County Comprehensive Plan that "where pollution
conditions now exist, all possible steps should be taken to
correct such conditions."
This alternative does not fulfill the goals of the Alki
community council that: "If it is economically and techni-
cally feasible, the unanimous vote of the committee is to
close down the Alki plant. The property, including the Bar
S playfields, should be reserved for use as park and recre-
ation area for the neighborhood and for Seattle residents."
Employment and costs. Employment and cost considera-
tions are developed in the Regional EIS.
92
-------
Alternatives and Impacts
Alternative D
Social, recreational, and cultural. Under this alter-
native^the Bar S baseball diamonds would not be affected,
which is considered favorable, minor, long-term, reversible,
local, and definite. However, degradation of the water near
the Alki outfall would continue with only primary treatment,
discouraging the recreational use of area beaches. This
effect would be less than under existing conditions for two
reasons: first, the Alki facility's outfall would be ex-
tended; and, second, combined sewer overflows will be par-
tially controlled.
Implementation of advance primary treatment at this
site may temporarily cause added traffic buildup in an area
that is already congested with beach traffic.
Archeological and historical. No known archeological
or registered historical sites would be affected by this
alternative.
Health and safety. There may continue to be health
risks associated with the consumption of shellfish due
to the discharge of effluent, as discussed in the biological
-section of the EIS.
An unlikely safety hazard is accidental leakage of
chemicals when they are in transport or handled on site.
Although nearly every U.S. water and wastewater treatment
facility uses chemicals, there have been very few chemical-
related accidents.
The health and safety problems related to sludge trans-
port and disposal would be as probable as for any other
trucks in transit.
Construction safety risk would be as for any other
similar construction: with safety conscious procedures
there should be little chance of accidents.
Aesthetics and nuisance. The Alki treatment facility
would continue to be a nuisance to local residents. It
would still have an industrial appearance and could still
be responsible for odors. These impacts would be adverse,
major, long-term, local, irreversible, and definite.
Although enhanced primary treatment produces more sludge
than primary treatment, the sludge dewatering facilities pro-
vided in this alternative significantly reduce the volume of
the sludge, and, hence, the number of truck trips required
93
-------
Alternatives and Impacts
Alternative D
for ultimate disposal. Under this alternative, 0.6 sludge
trucks per day would leave the Alki facility- This would
cause some nuisance on residential streets, and some conges-
ion along an already crowded beach front but the impact is
considered minor.
Mi'tigation Measures
While some odor-controlling measures have been imple-
mented, odor remains a problem at Alki. Odor control is
an important and feasible mitigation measure for all alter-
natives. The costs of odor control are being calculated
by Metro and will be available by the end of July, 1977.
Visual impacts of the facilities, which are highly
visible by service area residents from above, could be
mitigated by landscaping.
The effects on waters, sediments and biota off Alki
Point from BOD, solids, metals and toxicants identified or
suggested could be further reduced by employing enhanced
primary treatment year-round instead of just in the summer.
An improved chlorine feed system can be designed to
prevent chlorine levels in the sewage treatment plant efflu-
ent from exceeding toxic levels. This could be achieved by
matching chlorine levels to effluent discharge and/or in-
stalling a chlorine contact tank, which would maximize the
effectiveness of chlorination treatment. Currently,
chlorine is injected into the effluent flow at a constant
rate, calculated daily. This causes a fluctuating chlorine
residual.
Unavoidable Adverse Impacts
Under this alternative, the following adverse impacts
would be unavoidable.
Construction. Although construction activities can be
screened from public view, they will still be a temporary
nuisance.
Sludge trucking. Under current practices of disposing
sludge at remote sanitary landfill sites, there will neces-
sarily be sludge trucking.
94
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Alternatives and Impacts
Alternative D
Enhanced primary effluent on water quality and biota.
This alternative does not implement secondary treatment;
the minor water quality degradation of Puget Sound would con-
tinue as would effects on biota.
Noncompliance with PL 92-500. Public Law 92-500 re-
quires the installation of secondary treatment. This
alternative does not comply.
Land use. Land is required in all alternatives; the
question is: where will the impact occur?
Aesthetic nuisance of plant location. Wastewater
treatment facilities are a nuisance in all alternatives;
the question is: how can these nuisances be made smallest?
Operation and maintenance and capital costs. Construc-
tion of wastewater facilities, interceptors, and CSO holding
tanks is expensive. The facilities must be operated and
maintained.
Energy expenditures. Energy can in part be provided
by the methane produced in anaerobic digestion, but there
is still a large expenditure of energy which cannot be
mitigated.
95
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Alternatives and Impacts
ALTERNATIVE E, G, AND H
SECONDARY
Although the three alternatives are different on the
regional level, they all provide for upgrading the Alki
plant by 1983 to secondary treatment by the activated
sludge process in order to comply with PL 92-500. Under
these alternatives, there would be no change in the present
service area. Major additions or upgrading of the collection
system would not be provided. Measures to reduce combined
sewer overflows would not be taken either, and overflows
during wet weather would continue. However, overflows at
the pumping stations due to power failures would be
eliminated. Engine generators, as well as other improvements,
would be provided at each station.
The secondary process would include, in addition to the
existing primary facilities, aeration basins, secondary
clarifiers, chlorination facilities, and a chlorine contact
basin. The present pre-aeration, screening facilities, and
operation and maintenance buildings would be expanded. A
layout of the plant is shown in Figure 3- 7.
Sludge handling facilities would also be expanded to
handle additional sludge quantities resulting from secondary
treatment and additional sewered population. A new anaerobic
digester would be provided. To reduce the sludge volume and
truck traffic, the sludge would be dewatered by centrifuge
at Alki before being hauled to Cedar Hills landfill for
disposal.
The present outfall would be upgraded and extended to
provide adequate mixing of the effluent in Puget Sound.
The Alki plant upgrading and new structures would require
the acquisition of an additional 4.6 acres of publicly and
privately owned land located northwest of the site, which
is currently a public playground. Due to the higher elevation
of the playground area, a pumping station would be required
to pump the settled sewage from the primary tanks on the
existing site to the aeration tanks. The entire Alki project
is estimated to cost $26.5 million. Sludge generated in the
treatment process would be digested and dewatered on-site and
hauled to the Cedar Hills landfill as part of the regional
interim sludge handling and disposal plan,.
96
-------
Alternatives and Impacts
Alternative F
METRO-ALKI WASTEWATER TREATMENT PLANT
Figure 3-7
Alki Layout Alternatives E, G, and H
97
-------
Alternatives and Impacts
Alternatives Et G and H
Impacts
Primary impacts only are discussed here; secondary im-
pacts are evaluated in the Regional Analysis.
Geology, Soils and Topography
Alternatives E, G and H would require significant expan-
sion of the Alki treatment facility for secondary treatment
taking half of the space now used by the Bar S recreation
fields. Construction would require excavation of the bedrock.
There would be no significant adverse effect on the soils and
geology of the site from construction. Shoreline fill would
not be required, and no special soil engineering measures
should be necessary. The strength of the bedrock is not well
known but would be established through detailed site inves-
tigation prior to construction. Potential earthquake damage
is major. Potential for erosion is minor. Disposal of con-
struction waste could also pose a minor problem, limited in
extent but of long duration.
Outfall construction would have a major but limited and
probably short-term and reversible impact on benthic sediments
and light transmittance in overlying waters. It is assumed
that the outfall could mean an improvement in nearshore and
intertidal sediments potentially affected formerly in a minor
way by effluent moving onshore as a result of tidal currents
as at West Point. It is further assumed that the extended
outfall would initiate some changes in sediments, in addition
to those from construction, further offshore near the new
discharge point. The negative effects are potentially minor,
as the effluent plume would be small, and limited in extent on
the sediment of Puget Sound.
Earthquake damage to the outfall line could result from
shock waves or from submarine landslide (if the strata are
arranged appropriately). A break in the line would allow
effluent under pressure to boil up through the opening. The
probability of this event is the same for all alternatives
and is thus not further evaluated herein.
Building on the playfields would result in irreversible
changes to the soils underlying them and increase runoff at
the site. Erosion potential would increase during construc-
tion.
98
-------
Alternatives and Impacts
Alternatives E, G and H
Air Quality and Odors
Upgrading the Alki plant to secondary treatment would
increase the potential for odors escaping into the surround-
ing neighborhood. Because secondary treatment plants are
larger and more complex than primary plants, expose more
water surface area to the air and subject the water to more
perturbation, there is a greater likelihood for odors being
released into the surrounding neighborhood from secondary
treatment plants. Uncontrolled CSO's would continue to
cause intermittent odor problems. Improvement of the out-
fall would reduce, or perhaps eliminate, the potential for
odors arising from the discharge plume. The net result of
these alternatives would be an increased potential for un-
pleasant odors escaping to the surrounding neighborhood.
Water Quality
Under Alternatives E, G and H, secondary effluent would
be discharged through a modified Alki outfall. Flows would
be at baseline levels, but BOD and solids would be reduced
65 to 76 percent. Combined sewer overflows would continue
and increase with growth in sewered areas, as in baseline
(B) conditions. Nutrient (nitrogen) loads would continue as
in Alternative B from effluent discharge.
Temperature, DO and salinity would not be measurably
affected. Nutrients would be reduced onshore with extension
of the outfall, but still be introduced by CSO's. Nutrients
offshore would not be affected. CSO's would also continue to
cause increased suspended solids levels on beaches on occadion.
Health risks associated with coliforms could be reduced
somewhat through improvement of the outfall, but CSO's could
still have adverse effects. The source of bacteria which cause
shore waters to exceed fecal coliform standards for shellfish
has not been identified.
Potential chlorine toxicity problems would be reduced by
an improved, extended outfall and the addition of a chlorine
contact tank.
The discharge of heavy metals, pesticides and toxicants
would be substantially reduced by secondary treatment. Contri-
butions of these contaminants from uncontrolled CSO's is un-
known. Further studies are needed to compare the toxicants in
the Alki treatment plant discharge, which is continual, and in
CSO discharge, both of which probably have intermittent but
recurring impacts on beach and nearshore waters.
99
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Alternatives and Impacts^
Alternatives^ E-^ Gr and H
Biology
Alternatives E, G and H would involve secondary treat-
ment at Alki. Flows would continue at baseline levels, but
solids and BOD loads would be reduced 65 to 76 percent. Over-
flows and loads to Elliott Bay, West Seattle beaches and to
the Duwamish would continue at baseline levels. The Alki
outfall would be extended and improved.
Terrestrial habitats. Expansion of the site for sec-
ondary treatment would occupy an existing ballfield, which
is not considered to be an important terrestrial habitat.
If the new sites are landscaped, the shrubs and trees could
be beneficial in providing terrestrial wildlife a more
diverse habitat.
The intertidal. Overflows to Puget Sound at Alki/West
Seattle and Elliott Bay would remain at present annual levels
of 5.46 million gallons and 358 million gallons, respectively.
Alki treatment plant effluent, which is assumed to reach
adjacent beaches at least occasionally, would continue at
baseline levels but solids and BOD (and perhaps metals and
toxicants) loads would be reduced 65 to 76 percent. Elliott
Bay shores are probably not affected by effluents.
Nutrients, which could potentially be implicated in
increased growth rates of intertidal plants at Alki, would
probably not be removed in significant amounts by secondary
treatment of effluent and would, therefore, enter Puget
Sound in continued baseline amounts. Coliform bacteria in
shellfish could decrease somewhat, reducing health risks
from consuming them, if chlorination facilities are improved,
and with the extension of the Alki outfall. Bacterial and
pathogen inputs from CSO's would continue, however, and it
is impossible to determine whether or not state bacterial
standards for shellfish waters would be met. Better chlor-
ination would also reduce the risk of chlorine toxicity-
The reduction in solids, BOD and metals is considered
to be a minor limited benefit, as effects from these param-
eters have not been demonstrated on the intertidal. Metals
levels are slightly higher near outfall areas, but below
existing standards. Toxicants levels in effluents are un-
known, but removals in secondary treatment would have a posi-
tive effect. The benefit of metals and toxicants removals
would be long-term, no matter how small.
100
-------
Alternatives and Impacts
Alternatives E, G and H
It is not known which affects the intertidal community
more overall - CSO.'s or effluent. Effluent quantity is two
orders of magnitude larger, and quality is generally fairly
well known (except for toxicants and trace elements), but
its frequency of contact with the intertidal is not. CSO
quality, on the other hand, is poorly known, quantity rela-
tively small, but frequency of occurrence has been evaluated.
Puget Sound. Secondary treatment could potentially in-
clude improved disinfection - better kill with half the
chlorine. BOD, solids, and probably metals and toxicant
loads would be significantly reduced. Nutrient inputs would
continue at baseline levels. The extension of the Alki
outfall would reduce impacts to the nearshore areas, but
add nutrients closer to a mid-channel area where plankton
blooms develop. CSO's to Puget Sound waters would be as in
baseline conditions. Offshore free-swimming and bottom
dwelling organisms would be exposed to effluents containing
substantially less solids, metals and toxicants.
The assumed influence of the Alki effluent plume on
benthic community composition would continue the effects due
to nutrients; effects of solids and organic matter would
decrease. The abundance of clams and worms at the 150 foot
contour could become less pronounced.
The composition of fish assemblages near the outfall
may or may not change with secondary treatment. Some fishes
may be attracted to the organisms on the pipe or to the pipe
itself and would remain. Fishes which may be attracted by
prey species favored by effluent-caused changes in the
bottom or in the water column may also remain, although the
waters and substrates would be affected less. Any effect
on fishes would probably be short-term and reversible as many
of these species are transient in this area.
Eelgrass beds would benefit from the metals and toxi-
cants removals in secondary treatment, but not from the BOD
and solids removals as these areas are already rich in
organic matter.
Commercial and sport fisheries. Fish runs up the
Duwamish through Elliott Bay would be affected by CSO's at
unchanged levels from baseline (1975 or Alternative B).
Herring fisheries at Alki would be exposed to baseline
levels of CSO's, but the extension of the Alki outfall
would provide a benefit in that effluent would reach the
beaches less often or not at all depending on design.
101
-------
Alternatives and Impacts
Alternatives E, G and H
Juvenile herring and salmonids feeding in eelgrass beds
and other nearshore areas occasionally affected by effluents
would be benefited somewhat by the decrease in toxicants and
metals loadings which could build up in time in their prey.
The possibility of chlorine toxicity would probably be
eliminated by extension and improvement of the outfall. The
benefit is considered to be minor-to-moderate, and long-
term as effluent flows and CSO's would continue.
The Duwamish estuary. Overflows to the Duwamish would
continue essentially at baseline levels. The ecology of
the Duwamish is discussed in the Regional EIS.
Rare and endangered species. No rare or endangered
species are recorded from the study area. Sensitive habitats
have been described previously.
Natural Resources and Energy
Natural resources and energy impacts are not analyzed
on a site-specific basis. Rather, these considerations are
analyzed in the Regional Environmental Impact Statement on
an interrelated basis between the five existirg Metro plants
and potential new sites.
The Human Environment
Many of the human environment facets pertinent to the
Alki site are discussed and evaluated only in the Regional EIS.
This necessity to treat certain topics on a regional basis
stems from the interrelatedness of the plants and the trader-
offs between alternatives.
Land use. Under these alternatives, the Alki treatment
plant would be expanded to include secondary treatment, requir-
ing the land of one of the two Bar S baseball playing fields.
This land is currently -owned by Seattle Department of Parks
and Recreation; Metro has an option on it. The impact of
using this land is considered adverse, minor, long-term, local,
irreversible, and definite.
Construction would require a permit from the Seattle
Shorelines Master Plan, and perhaps other agencies.
102
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Alternatives and Impacts
Alternatives E, G and H
Legal and institutional. Legal issues are developed
in the Regional EIS. These alternatives fulfill the require-
ments of PL 92-500. The timing involved in completing second-
ary treatment construction is of consideration, as is
explained in the Regional EIS.
Agency and neighborhood goals. These alternatives ful-
fill the goal stated by the PSCOG that "existing public
utilities, facilities, and services shall be used to their
fullest prior to expansion" and, in part, fulfill the goals
of the King County Comprehensive Plan, that, "where pollu-
tion conditions now exist, all possible steps should be
taken to correct such conditions."
These alternatives do not fulfill the goals of the Alki
community council that: "If it is economically and technically
feasible, the unanimous vote of the committee is to close
down the Alki plant. The property, including the Bar S play-
fields, should be reserved for use as a park and recreation
area for the neighborhood and for Seattle residents."
Employment and costs. Employment and cost considerations
are developed in the Regional EIS.
Social, recreational and cultural. Under this alter-
native, one of the two baseball diamonds at the Bar S
field would be used for expansion of the facility.
Although the Alki residents hope to keep the Bar S playing
fields intact, they would prefer to condemn these fields rather
than condemn more private property- The impact of this recre-
ational restriction would be adverse, minor, long term, local,
irreversible, and probable.
Expansion at this site may temporarily cause added traffic
buildup in an area that is already congested with beach traffic.
This alternative would improve the water quality off Alki
point, which may make the Alki beaches more attractive for
recreation. This would tend to balance the loss of recreational
opportunity at the ballfield.
This alternative would have no impact in the Duwamish
area, as it includes no expansion into that area.
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-------
Alternatives and Impacts
Al; ter:na ti y.es; $ fl ,:: G ; a n d r H n
Alternatives E, G and F
Archeological and historical . No known archeological,
or reg^fee^^g^^o^^j^^s^ould &§ af^etgd JpXo^§.cal,
ait§g§ff%M§edr"histofical sites would be affected by this
alternative .
Health and safety. There may be fewer health risks
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iimpprtant andi f easible^wit.igaiion, ..pi^a^^ure ,f,p,rr al,l.^^frji§t^
o costs pf odor0contrpltarf jbeingr^calculated,, by ^e^,rpnji-nd
betavajlable by the i end- .a£ ^.July , ,19,77 ,ted ''
-------
Alternatives and Impacts
Alternatives E, G and H
by installing tennis courts on top of the. secondary clarifiers.
Visual impacts of the facilities which are highly visible
by service area residents from above, could be mitigated by
landscaping.
Unavoidable Adverse Impacts
Under this alternative, the following adverse impacts
would be unavoidable.
Construction. Although construction activities
can be screened from public view, they will still
be a temporary nuisance.
Sludge trucking. Under current practices of dis-
posing sludge at remote sanitary landfill sites,
there will necessarily be sludge trucking.
Combined sewer overflows. This alternative does
not take adequate measures to control CSO's; they
will still occur in wet weather.
Land use. Land is required in all alternatives;
the question is: where will the impact occur?
Aesthetic nuisance of plant location. Wastewater
treatment facilities are a nuisance in all alter-
natives; the question is: how can these nuisances
be made smallest?
Operation and maintenance and capital costs. Construction
of wastewater facilities, interceptors, and CSO holding
taks is expensive. The facilities must be operated and
maintained.
Energy expenditures. Energy can in part be pro-
vided by the methane produced in anaerobic diges-
tion, but there is still a large expenditure of
energy which cannot be mitigated.
105
-------
Alternatives and Impacts
Alternative F~
ALTERNATIVE F
SECONDARY TREATMENT/SOUTHERN STRATEGY
Similar to Alternative C, the treatment plant at Alki
would be entirely abandoned and the site vacated (see
Figure 3-5), but this change would occur earlier in Alterna-
tive F, by 1985. Flows from the Alki service area during
both dry and wet weather would be transferred to and treated
at the new Duwamish treatment plant.
The new 50 mgd secondary treatment plant would be
constructed in the lower Duwamish by 1985, adjacent to the
existing Duwamish pumping station on Harbor Avenue. In
addition to serving the Alki area, the plant would serve the
southerly portion of the West Point service area. A possible
layout of the plant is shown in Figure 3-8. The Duwamish
plant would treat 50 mgd average, 145 mgd peak flows.
Modifications to the existing Renton collection system
would be required to bring Renton flows to the Duwamish
plant. Plant effluent would be transferred to Alki Point
via the same tunnel used for transferring Alki wastewater,
with discharge to Puget Sound through a new outfall and
diffuser. The effluent tunnel and outfall would be sized
for the inclusion of Renton effluent, thus removing Renton
discharge from the Duwamish River at a later date. This
would require construction of a new Renton transfer line to
an effluent pumping station located at the Duwamish plant.
Sludge facilities at the Duwamish plant would include
digesters sized to serve the Alki and south West Point
service area, plus sludge storage and receiving facilities
sized for handling Renton and West Point sludges. Space
would also be made available for construction of dewatering
equipment at a later date as dewatered sludge reuse options
become more definite.
Under this alternative, the combined sewer overflows to
Puget Sound would be reduced. The overflows at the plant and
63rd Street pumping station would be eliminated due to the
abandonment of the former and enlargement of the latter.
Overflows due to power failure at the various pumping stations
would be eliminated also, since provisions are made under this
alternative to include an engine generator at each station.
106
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Alternatives, ^nd Impacts
Alternative F
METRO-HARBOR AVENUE S.W. TREATMENT PLANT
(DUWAMISH)
.REQUIRED FOR CENTRALISl
SLUDGE FACILITY
WAS, THICKENER
•EFFLUENT PUMPING
ILOatSULFONATDN
AERATION TANK
SECONDARY - - AIR ACTIVATED SLUDGE
Figure 3-8
Alki Layout Alternative F
107
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Alternatives and Impacts^
Alternative^ F
Impacts
Primary impacts only are discussed here; secondary
impacts are evaluated in the Regional EIS.
Geology, Soils and Topography
Alternative F includes abandonment of the Alki facility
with construction of a new secondary treatment plant in the
Duwamish. The Alki outfall would be improved and carry flows
from both the new plant and from Renton. A slightly larger
tunnel than in Alternative C would be opened under West Seattle
and the Duwamish River, a major construction project. The
effects of the tunnel would be about the same as in Alterna-
tive C. Stability is not expected to be a major problem in
the glacial deposits affected. There is, however, some risk
of reducing the stability of adjacent bluffs, particularly
near the portals. Disposal of muck from the tunnel excava-
tion may pose a major environmental problem, depending on
where this material is taken for disposal.
The currently favored Duwamish sites are in areas of
deep alluvial or fill deposits, and any structures erected
there would require piling and dewatering for foundation
support. Necessary pre-construction studies of local soil
conditions and the special precautions necessary to ensure
stable foundations would add to the duration and cost of con-
struction. Such soils also carry the highest earthquake hazard
risks. The precautions necessary to deal with the above
hazards are well known, however. The impact of construction
waste (debris) disposal could be adverse, minor, and limited
in extent but of long duration on the ultimate disposal site(s)
due to materials leaching out of the waste.
At Alki, the treatment plant would be dismantled and the
site graded to the level of the existing adjacent ballfield.
This process would, like construction, generate dust, erosion
potential and construction waste disposal site concerns.
The new outfall is assumed, as in other alternatives, to
allow improvement in nearshore sediments near the present
outfall site and initiate changes in the sediments at the
new discharge point. The impact is assumed to be moderate as
the plume will be 18 times larger, limited in extent,
irreversible and long-term, as non-degradable industrial
wastes would be entering Puget Sound from the Renton facility.
108
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Alternatives and Impacts
Alternative P
Air Quality and Odors
The odor problems associated with the Alki treatment
plant would be eliminated by abandonment of Alki. A new
secondary treatment plant in the Duwamish valley, which is
subject to poor air circulation, frequent temperature inver-
sions, and already high pollutant loads, would create a
potential for odor problems in this area. The secondary
treatment plant could be more of an odor problem than the en-
hanced primary plant of Alternative C, because secondary
treatment plants are larger and more complex than primary
plants, expose more water surface area to the air and subject
the water to more perturbation.
Although the Duwamish plant would discharge off Alki
Point, the extended outfall should reduce or eliminate the
potential for odors arising from the discharge plume.
Water Quality
Under Alternative F, a new secondary treatment facility
would be built in the Duwamish. Duwamish wastewater and
Renton secondary effluent would both be discharged through
a new Puget Sound outfall at Alki Point. CSO abatement
depends on facility sizing, but is expected to be essentially
complete (97%) at Alki Beach (Metropolitan Engineers, June,
1977 ) •
Therefore, a singificantly large flow of chlorinated
effluent would be discharged to Puget Sound at Alki, but of
higher quality (secondary treatment) than at present. Combined
Renton and Duwamish flows are expected to average 144 mgd, with
peak flows of 404 mgd. These flows would be almost 50% larger
than the West Point secondary plant under F, based on average
flows (144 mgd versus 97 mgd). Solids and BOD loads would be
similarly larger. This major new point source at Alki could
have effects of unknown magnitudes, but possibly similar to
those at West Point. Outfall design will determine whether or
not effluent from the new outfall reaches the shore due to
the current patterns at the Point.
Nutrients inputs would increase drastically at this point
with the 18-fold increase in effluent flows. Solids and BOD
loads would increase 4.5 times and 3.4 times over base level
inputs to the Sound at Alki. The new outfall would discharge
109
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Alternatives and Impacts
Alternative F
near one of the two areas in central Sound where major algae
blooms develop. It is not known whether or not any effects
would result on primary productivity -
The increase in BOD and solids load to Puget Sound at
Alki could be paralleled by an increase in metals and toxicants
loads, perhaps of similar magnitudes. At the same time, CSO
abatement should reduce heavy metals and toxicants in beach
and nearshore waters.
In summary, large flows of secondary treated wastewater,
in spite of CSO abatement, should increase the loads of
nutrients, solids, BOD, heavy metals, and toxicants to near-
shore and perhaps beach waters at Alki. The benefits of
secondary treatment offshore appear to be overshadowed by the
substantially increased flows and loads passing through the
Alki outfall from the Renton and Duwamish treatment plants.
Because the Renton and Duwamish service areas include more
industry than that of Alki, the volume of heavy metals and
toxicants discharged would also increase. More information
is needed on the tradeoffs involved in this alternative before
accurate conclusions can be reached. The benefits to the
Duwamish River of transferring Renton and Duwamish dis-
charges to Puget Sound are discussed in the Regional EIS.
Biology
Under Alternative F, all effluents would receive sec-
ondary treatment. The effluent from a new secondary plant
in the Duwamish and from Renton would enter Puget Sound
through a new improved outfall at Alki, creating a major
point source of 144 mgd, about 50% larger than West Point
at that time (97 mgd). Most of the facilities at Alki would
be abandoned and removed. Overflows to Alki/West Seattle
would be reduced by 97%.
Terrestrial habitats. The removal of the treatment
plant at Alki would allow for development of a park at the
site. The trees and shrubs would create habitat diversity
beneficial to wildlife. The effect could be moderate,
limited in area, and of long duration. Such landscaping,
however, is not part of the alternative costs shown.
110
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Alternatives and Impacts
Alternative F
The intertidal. Overflows to Puget Sound would be re-
duced - 15% to Elliott Bay, 97% to Alki. Flows entering
the Sound at Alki would increase by 15 times, BOD by 3
times, and solids by 4 times. Because of physiographic
similarities, it is possible that effluent from a new Alki
outfall would come inshore just as at West Point and as
assumed at Alki now. The frequency of such an event cannot
be determined, as it is unknown now and the properties of
the new outfall are undetermined. The risk of chlorine .
toxicity in the intertidal would be reduced due to addition
of a chlorine contact tank and improvements so that the
outfall would be further offshore and would have a diffuser
section. With CSO control and the new outfall, the bac-
terial levels in intertidal areas could be reduced. Whether
or not state fecal coliform standards for shellfish waters
would then be met cannot be determined as the source(s) of
bacteria has not been identified.
Puget Sound. Loads of nutrients, BOD, solids and
probably metals and toxicants would significantly increase
at Alki.
Offshore phytoplankton would probably be affected by
the higher level of nutrients, and the distribution may be
altered through extension of the Alki outfall, such that
an enrichment may develop near the outfall.
The major new plume would discharge near one of the two
areas in central Sound where algae blooms develop. The
increase seen in primary productivity extremes in the
vicinity of West Point would appear similarly near the new
Alki outfall from which effluent discharge would be 50%
greater than West Point in 2005. The resulting effect
on zooplankton is unknown. An enriching effect on the algal
productivity of central Puget Sound is considered to be a
moderate, negative impact, extensive and of long duration
as flows continue, but reversible.
Coliform bacteria levels in waters could decrease, reduc-
ing health risk from consuming shellfish, with the extension
and improvement of the Alki outfall. Overall bacterial
and virus inputs to Puget Sound from overflows would increase,
but would probably not be a problem in being dilute . Whether
strict -state fecal coliform standards would be met cannot be
determined at this time. Improved chlorination could also
reduce the risk of occasional chlorine toxicity of unknown
magnitude to animals near the outfalls.
Ill
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Alternatives and Impacts
Alternative F
The apparent influence of the West Point effluent in
benthic communities is assumed to occur similarly at Alki.
Whatever the existing effect at Alki, it would be greatly
increased by the larger nutrient, BOD and solids loads enter-
ing Puget Sound at this point. Loads of metals and toxicants
would also increase, but by an unknown amount at this site
even with secondary treatment.
The composition of the fish assemblage near the outfall
may or may not change with secondary treatment and many fold
increase in the size of the effluent plume, as the causes of
attractions of particular species to the outfalls have not
been identified. Those attracted to the pipe or the organ-
isms which attach to it would remain or increase.
The slightly elevated incidence of tumorous flatfish at
West Point may or may not change with secondary treatment of
effluent, as the cause(s) of the phenomenon are unknown. It
would be of value to monitor the incidence of tumorous fishes
at Alki with the installation of the new outfall and greatly
increased discharges at that point. In general, the existing
nektonic and benthic community situation at Alki is so little
described in the literature as to make judgements of future
effects impossible.
Commercial and sport fisheries. The fish of the Duwamish
-Elliott Bay would receive moderate benefit from 1) the trans-
fer of Renton effluent to Alki with effluent from the Duwamish
secondary plant and 2) a 15% decrease in overflows to the
Elliott Bay. Flows, BOD and solids, would be reduced as
would stresses due to low DO, metals and toxicants. The
effects of the removal of Renton effluent are described in
the Regional EIS.
Herring fisheries and eelgrass beds at Alki would pro-
bably benefit from the essential elimination (97% reduction)
of overflows to the Alki/West Seattle beaches in Alternative
F and from the extension of the Alki outfall. Juvenile and
larval herring, salmonids and bottom fish feeding inshore in
areas occasionally affected by effluents, would probably bene-
fit from the decrease in toxicants and metals loadings which
otherwise could accumulate in their prey- The beneficial
impact could be minor to moderate, possible, somewhat limited
in the central Sound and long-term as effluents continue.
The Duwamish estuary. CSO's to the Duwamish would re-
main at baseline (Alternative B) levels. The removal of
Renton effluent is discussed in sections on secondary impacts
in the Regional EIS. Primary impacts would continue to be
minor-to-moderate, fairly extensive in the waterway and of
112
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Alternatives and Impacts
Alternative F
long duration as continuing events. Effects \vould be essen-
tially irreversible for metals and toxicants.
Rare and endangered species. No listed species are
recorded from the study area. Sensitive habitats have been
discussed previously-
Natural Resources and Energy
Natural resources and energy impacts are not analyzed
on a site-specific basis. Rather, these considerations are
analyzed in the Regional Environmental Impact Statement on
an interrelated basis between the five existing Metro plants
and potential new sites.
The Human Environment
Many facets of the human environment pertinent to the
Alki site are discussed and evaluated only in the Regional
EIS. This necessity to treat certain topics on a regional
basis stems from the interrelatedness of the plants and the
trade-offs between alternatives.
Land use. At Alki, the facility would temporarily
continue with primary treatment which would not require the
acquisition of new land; by 1985 the Alki facility would be
abandoned, to be replaced by a secondary treatment facility
at the Harbor Avenue site on the Duwamish.
The eventual abandonment of the Alki site would be
favored in the Alki area. Data is being collected on the
response of Duwamish area residents to a wastewater facility
in their community.
Legal and institutional. Legal issues are developed
in the Regional EIS. This alternative fulfills the require-
ments of PL 92-500.
Agency and neighborhood goals. This alternative ful-
fills the goals of the Alki community council that: "If
it is economically and technically feasible, the unanimous
vote of the committee is to close down the Alki plant. The
113
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Alternatives and Impacts
Alternative F
property, including the Bar S playfields, should be re-
served for use as a park and recreation area for the neighbor-
hood and for Seattle residents."
This alternative also attempts to fulfill the
priorities set by the PSCOG that "natural amenities identi-
fied as important to the region's character and beauty shall
be preserved or sensitively developed as a second choice"
by abandoning the Alki facility, which is on prime beach
land; but does not fulfill the same agency's goal that
"existing public utilities, facilities, and services shall
be used to their fullest prior to expansion" when the still-
operable Alki facility is abandoned.
Employment and costs. Employment and cost consider-
ations are developed in the Regional EIS.
Social, recreational and cultural. The proposal of
removing the Alki wastewater facility is greatly applauded
by Alki residents. Under this alternative, the Bar S base-
ball diamonds would not be affected, which is considered
favorable, minor, long-term, reversible, local, and definite.
Further, the land which is currently used for the wastewater
treatment facility could eventually be used for other recre-
ational purposes.
Degradation of the water near the Alki outfall would be
reduced with secondary treatment; further, the outfall would
be extended into the Sound. These actions may increase the
recreational usefulness of the Puget Sound water if the
beneficial effects are not offset by the greatly increased
flows.
It is now being determined what social, recreational
and cultural effects a wastewater treatment facility will
have on the Duwamish area.
Archeological and historical. No known archeological
or registered historical sites would be affected by this alter
alternative.
Health and safety. There may be fewer health risks
associated with the consumption of shellfish due to the
discharge of secondary effluent rather than primary effluent,
as discussed in the biological section of the EIS.
An unlikely safety hazard is accidental leakage of
chemicals when they are in transport or handled on site.
Although nearly every U.S. water and wastewater treatment
facility uses chemicals, there have been very few chemical-
related accidents.
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Alternatives and Impacts
Alternative F
The health and safety problems related to sludge trans-
port and disposal would be as probable as for any other
trucks in transit.
Construction safety risk would be as for any other
similar construction: with safety conscious procedures there
should be a slim chance of accidents.
Aesthetics and nuisance. The Alki facility would
be phased out, eliminating a major nuisance in the Alki area,
but would be' replaced by the Harbor Avenue site; it is
still being determined how much of a nuisance the Harbor
Avenue facility would be.
Under this alternative, 4.8 sludge trucks per day would
leave the Duwamish facility. These would cause some nuisance,
but the effect is considered minor; this traffic would proba-
bly not change ambient noise levels in this additional
region.
Mitigation Measures
While some odor-controlling measures have been imple-
mented at Alki, odor remains a problem. Odor control is
an important and feasible mitigation measure for Alterna-
tive F until 1985 when the Alki plant is abandoned. The
costs of odor control are being calculated by Metro and
will be available by the end of July, 1977.
The currently unknown but potentially major effects of
a large new point source to Central Puget Sound at Alki on
sediments, water quality and biology and the means of pre-
venting effluent from coming ashore could be identified
and mitigated with a comprehensive study of the current,sedi-
ments, water quality and biology before outfall design begins.
All of the field evaluations, theoretical and physical models
could profitably be employed to this end.
Visual impacts of the facilities, which are highly visible
by service area residents from above, could be mitigated by
landscaping.
The data base for evaluation of impacts on the Duwamish
sites could be improved through thorough investigation of
soils and foundation characteristics, socio-economic charac-
teristics, and archaeological sites.
Alternative sites to the Harbor Avenue location in the
Duwamish area should receive continued attention.
115
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Alternatives and Impacts
Alternative F
Unavoidable Adverse Impacts
Under this alternative, the following adverse impacts
would be unavoidable.
Construction. Although construction activities can be
screened from public view, they will still be a temporary
nuisance.
Sludge trucking. Under current practices of disposing
sludge at remote sanitary landfill sites, there will
necessarily be sludge trucking.
Land use. Land is required in all alternatives; the ques-
tion is: where will the impact occur?
Aesthetic nuisance of plant location. Wastewater treat-
ment facilities are a nuisance in all alternatives; the
question is: how can these nuisances be made smallest?
Operation and maintenance and capital costs. Construction
of wastewater facilities, interceptors, and CSO holding
tanks is expensive. The facilities must be operated
and maintained.
Energy expenditures. Energy can in part be provided by
the methane produced in anaerobic digestion, but there is
still a large expenditure of energy which cannot be miti-
gated .
116
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SUMMARY OF IMPACTS
Geology, Soils and Topography
Potential impacts at the Alki and Duwaraish sites were
evaluated with respect to slope and foundation stability,
earthquake damage risk, erosion and deposition, topography,
soil damage risk, soil profile, and marine sediments. Sludge
disposal and construction waste disposal site problems are
evaluated in the Regional EIS. Duwamish sites were evaluated
in Alternatives C and F.
As anticipated, those alternatives requiring the most
construction have the greatest potential negative impact on
land resources. All Alternatives but A include improvements
to the Alki outfall; in C it would be abandoned in 1995, and
in F it would carry 15 times the baseline flow. Alternatives
C and F, which require major construction in the Duwamish,
dismantling of existing structures at Alki plus the construc-
tion of a major tunnel from Alki to the new facility, are
considered to carry the greatest potential negative impacts.
The Duwamish sites are on fill; the Alki site is part
moderately consolidated soils and part bedrock. All are
subject to risk of major earthquake damage if structures are
not constructed to withstand substantial ground shaking and
differential settlement.
Alternatives E, G and H require expansion at the Alki
site for secondary facilities, requiring one of the two
adjacent ballfields. The impact of these alternatives is
judged to be somewhat less than the construction of a new
plant in the Duwamish area under Alternatives C and F, but
still important. Alternative D requires less construction
to accommodate enhanced primary facilities; Alternative B re-
quires the least in just improving the Alki outfall.
Air Quality and Odors
Alternative A would continue the present odor problem
at Alki. Odors could be reduced somewhat by outfall improve-
ments under Alternatives B, C, D, E, G and H. Odors arising
from treatment plant operation would continue under Alterna-
tives B and D. Abandonment of the plant in 1995 under Alter-
native C or 1985 under Alternative F would eliminate the
odor problem at Alki. Upgrading the secondary treatment as
proposed in Alternatives E, G and H could exacerbate the
117
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Alternatives and Impacts
Summary
current odor problem. The potential for generation of aero-
sols containing pathogens would increase with secondary
facilities, but is considered to be negligible. Construc-
tion of new facilities would temporarily raise dust levels
by a moderate degree over a limited area. Operation of a
new enhanced primary treatment plant under Alternative C or
a second treatment plant under Alternative F would create a
potential for odor problems in the Duwamish area. The
proposed holding tanks are discussed in the Regional EIS.
Water Quality
The waters near Alki are subject to contaminant inputs
from a variety of sources, only some of which, such as efflu-
ents and CSO's are controllable by Metro. As a result, no
proposed alternative completely eliminates impacts on water
quality-
The extension and improvement of the Alki outfall in
Alternatives B, C (until 1995), D, E, G and H is expected
to reduce chlorine toxicity potential and pathogens, BOD,
solids, metals and toxicants concentrations in nearshore
and intertidal waters to an undetermined degree.
Overflows to Alki/West Seattle beaches would be reduced
97% by Alternatives C and F, and 18% by D. Alternatives E,
G and H would continue such overflows at baseline (Alternative
B) levels.
Effluent solids and BOD loads, and associated metals and
toxicants loads would be reduced at Alki most by C when the
plant is ultimately abandoned and discharge ceases. The
loads would be transferred to the Duwamish estuary. Secondary
Alternatives E, G and H reduce effluent loads most (70-77
percent) after C. Enhanced primary treatment in D moderately
reduces loads by about 22% over baseline (B) levels, to the
levels seen in 1975. Alternative D can be construed as a
non-degradation over present levels, but secondary alterna-
tives reduce loads significantly. Alternative F would intro-
duce greatly increased loads off Alki from the Duwamish area.
Nutrients (nitrogen) loads would be at baseline levels
in C (until 1995), D, E, G and H. In Alternative F, flows
and nutrients which are not removed by secondary treatment,
would increase 15-fold to the Sound at this point. Solids,
BOD, and probably metals and toxicants loads to Puget Sound
118
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Alternatives and Impacts
Summary
would increase significantly over baseline levels for Alki,
even though the new flows receive secondary treatment, due
to the increased volume of flows and industrial wastes from
the Renton service area.
Biology
The eight alternatives at Alki were analyzed with res-
pect to their impacts on biologic systems, including terres-
trial habitats, the intertidal, Puget Sound, the Duwamish
estuary, commercial and sport fisheries, and endangered
species.
Terrestrial Habitats
At Alki and the Duwamish the proposed sites contain
a negligible amount of terrestrial vegetation. The effects
of construction would be negligible. Moderate positive
effects could be achieved through landscaping, in which
case Alternatives C and F, which allow for the greatest
conversion to parkland, are most beneficial. The other
alternatives allow for only minor-to-moderate landscaping.
Landscaping is optional in all alternatives, however, and
has not been included in facilities planning alternative
costs.
The Intertidal
The service area intertidal is subject to sewer over-
flows primarily at Elliott Bay and at Alki/West Seattle.
There is evidence of treatment plant effluent coming ashore
at West Point, and current patterns suggest this phenomenon
could occur adjacent to Alki. The frequency and distribu-
tion of the events are unknown. An apparent enrichment of
algae at West Point and perhaps at Alki have been suggested
as results of this. Also, fecal coliform bacterial levels
exceed state shellfish water standards at all sites in the
area. The source of bacteria has not been identified. No
effects of effluent have been suggested for intertidal
animals except grazers on algae which appear to show in-
creased growth rates.
119
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Alternatives and Impacts
Summary
Overflows are small inputs relative to effluents; their
frequency is fairly well known and quality poorly known.
Effluent quality is known and frequency of impact on the
intertidal unknown.
Overflows to the intertidal would be greatly reduced by
Alternatives C and F, and slightly by Alternative D. C$0
levels w.ould be at baseline levels for Alternatives A> B, E,
G and H.
Effects of solids and BOD and associated metals and toxi-
cants in effluent would be reduced by 70 to 75 percent below
baseline levels by secondary Alternatives E, G, and H. Solids
and BOD loads to Alki from F would increase 4 and 3 times,
respectively. Enhanced primary treatment, Alternative D,
reduces these parameters by 28 and 24 percent below baseline
B levels. Alternatives E, G and H actually improve effluent
loads substantially. Alternative C eventually eliminates
effluent effects altogether. Alternative F would greatly
increase loads and flows with unknown effects on the inter-
tidal.
Puget Sound
This category includes the biota of nearshore and off-
shore waters which are affected far less by sewer overflows
than by effluents. Total nutrients loads to Puget Sound
would be essentially unchanged in all Alternatives but F,
which includes transferring Renton's flow into the Sound
via a new Alki outfall. This would place a much larger
nutrient source near one of the two places in the central
Sound where major algal blooms develop.
Apparent changes in the diversity, abundance, and composi-
tion of bottom communities at West Point in the typical efflu-
ent plume position and along the depth contour at which
effluent has neutral buoyancy are assumed to occur at Alki as
well although this site was not sampled. The effects on
animals are judged to be more related to solids and BOD loads
than nutrients and so are more affected by effluent treatment
levels. Thus secondary treatment Alternatives E,G and H would
probably decrease the magnitude of the effect seen in time;
Alternative, D would maintain it at present (1975) or A levels
but would be a decrease from baseline B levels. Alternative C
in eliminating the plume, would probably allow for a decrease
in the effects. Alternative F, in greatly increasing the
plume, would probably increase them. Higher metals levels in
Puget Sound biota near the outfall would be similarly reduced
120
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Alternatives and Impacts
Summary
most by C, next by E, G and H as secondary treatment removes
substantially more metals than enhanced primary treatment,
and perhaps increased by F.
The cause(s) of the elevated incidence of tumorous flat-
fish at West Point has not been identified. The presence of
the outfall pipe and/or its contents may be involved, but to
an unknown extent; as a result, the effects of the various
alternatives on disease incidence cannot be determined.
Monitoring at Alki of disease incidence with Alternative F
is recommended.
Under Alternatives A, B, C (until 1995) and D, the
chlorine feed rate would be adjusted manually on a daily basis
regardless of hourly fluctuations in effluent flow. This
could result in overchlorination (toxic residuals in effluent)
or underchlorination (insufficient bacterial removal). Aver-
age residuals have been calculated to occur to or above
threshold levels for chronic effects, but no toxic effects
have been observed in the field. Both improved chlorination
and dechlorination facilities (chlorine contact tank and
sulfonator, respectively) are included under Alternatives
E, F, G and H. These would mitigate possible toxicity and
underchlorination problems associated with the existing
chlorination system.
Commercial and Sport Fisheries
Fish runs up the Duwamish through Elliott Bay would
benefit by F, which transfers Renton flow from the
Duwamish to Puget Sound and reduces Elliott Bay overflows
by half. Under C, Renton flows to the Duwamish would be
greatly increased and primary treated wet weather flows of
up to 250 mgd would also go to the Duwamish —with undeter-
mined effects . Alternatives D, E, G, and H would have the
same effects as in Alternative B.
The Duwamish Estuary
The estuary would be benefited by F, which transfers
Renton flows to Alki, and somewhat less by H, which has 16
percent lower flows to the Duwamish than baseline. An ex-
panded Renton facility would have major effects on DO and
nitrates in the estuary as the flows would almost equal the
river's flow in summer. A large hew discharge to the
Duwamish in Alternative C could have adverse impacts, but
of undetermined magnitude.
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Alternatives and Impacts
Summary
Rare and Endangered Species and Sensitive Habitats
No listed rare or endangered species are recorded
from the study area. Critical or sensitive habitats, such
as salmon rearing areas, fish migration routes, and water-
fowl areas were discussed in other sections.
Natural Resources and Energy
Natural resources and energy impacts are not analyzed
on a site-specific basis. Rather, these considerations are
analyzed in the Regional Environmental Impact Statement on
an interrelated basis between the five existing Metro plants
and potential new sites.
The Human Environment
Many of the human environment facets pertinent to the
Duwamish and Alki sites are discussed and evaluated only in
the Regional EIS. This necessity to treat certain topics on
a regional basis stems from the interrelatedness of the plants
and the trade-offs between alternatives.
Land Use
Under Alternatives A and B there would be no expan-
sion of the Alki site; under Alternatives C and D the ex-
pansion to enhanced primary would require no new land
(under Alternative C, the Alki facility would eventually
be phased out).
Under Alternatives E, G and H, expansion would use up
one of the two baseball diamonds in Bar S Park. This park
is currently operated by the Seattle Department of Parks
and Recreation, but Metro has the right to develop it.
The Alki facility is on prime residential real estate;
adjacent to a highly used beach. The impact of this land
use is considered adverse, minor, long-term, irreversible,
and definite under the alternative s which use this site.
The expanded facility would use nearly twice as much land
as the primary plant.
122
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Alternatives and Impacts
Summary
Under Alternatives C and F, the Duwamish sites of
Diagonal Way and Harbor Avenue would be developed, respective-
ly. Data is still being collected on the impact these Duwamish
sites would have on land use.
Construction at any of these sites within 200 feet of
the shoreline would require a permit from the Seattle Shore-
lines Master Plan.
Legal and Institutional
Legal issues are developed in the Regional EIS. Alter-
natives E, F, G and H comply with PL 92-500; Alternatives
A, B, C and D do not. The NPDES permits also require com-
pliance with a permitted time schedule, which is still being
negotiated.
Agency and Neighborhood Goals
Many of the agency and neighborhood goals are de-
veloped in the Regional EIS. Those which can be most
adequately developed in the Alki document are as follows:
The goals of the Alki community council state that: "If
it is economically and technically feasible, the unanimous
vote of the committee is to close down the Alki plant. The
property, including the Bar S playfields, should be re-
served for use as park and recreation area for the neighbor-
hood and for Seattle residents."
Alternatives A, B, D, E, G and H do not fulfill this
desire of removing the facility; Alternatives E, G and H,in
fact, implement expansion of the Alki facility. The Alki
Plant is phased out only in Alternatives C and F. The im-
pact on the Alki neighborhhod of phasing out the Alki facil-
ity would be favorable, major, long-term, irreversible, local
and probable.
The impact on the Duwamish area of having a wastewater
facility nearby, as would occur in Alternatives C and F, is
still being determined.
Of 370 Alki residents interviewed, fifty-nine percent
expressed a ,preference for upgrading sewage treatment facili-
ties to secondary treatment, as required by law. Alterna-
tives E, F, G and H would fulfill this objective; Alterna-
tives A, B, C and D would not.
123
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Alternatives and Impacts
Summary
Alternatives C and F attempt to fulfill the
priorities set by the PSCOG that "natural amenities identi-
fied as important to the region's character and beauty shall
be preserved or sensitively developed as a second choice",
by abandoning the Alki facility, which is on prime beach
land; however, Alternatives C and F do not fulfill the
same agency's goal that "existing public utilities, facili-
ties , and services shall be used to their fullest prior to
expansion," in light of the fact that the still-operable
Alki facility would be abandoned.
Employment and Costs
Employment and cost considerations are developed in
the Regional EIS.
Social, Recreational and Cultural
One of the two Bar S baseball diamonds would be condemned
if secondarytreatment is installed at Alki, as is proposed
under Alternatives E, G and H. This impact on recreation
would be adverse, minor, long-term, reversible, local, and
definite. Under Alternatives A, B and D, there would be no
impacts on the Bar S playing field. Under Alternatives C
and F, the Bar S fields would not be affected; further, with
abandonment of the Alki wastewater plant, more recreational
facilities could be installed.
Recreational usage of Alki beaches may be slightly
affected by the presence of wastewater discharge and CSO
outfalls; statistics on this are not available.
Currently, the water for the beaches at Alki do not
exceed water quality parameters for bathing standards.
Archeological and Historical
No known archeological or registered historical sites
would be affected by any of the alternatives at Alki.
An archeological site has recently been discovered
across the Duwamish river from the Diagonal Way site. The
Diagonal Way site should be investigated before this site
is built upon, which would occur under Alternative C.
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Alternatives and Impacts
Summary
No data is available on the Harbor Avenue site, which
would be developed under Alternative F.
Health and Safety
In Alternatives A, B, c and D, there may continue to be
health risks associated with the consumption of shellfish
due to the- discharge of primary effluent, as discussed
in the biological section of the EIS. Under secondary treat-
ment, Alternatives E, F, G and H, this risk would probably
decrease.
An unlikely safety hazard is accidental leakage of
chemicals when they are in transport, or handled on site.
Although nearly every U.S. water and wastewater treatment
facility uses chemicals, there have been very few chemical-
related accidents.
The health and safety problems related to sludge trans-
port and disposal would be as probable as for any other
trucks in transit.
Construction safety risk would be as for any other
similar construction: with safety conscious procedures
there should be a slim chance of accidents.
The safety risks related to chemicals, sludge transport,
and construction would be minimal under all alternatives.
Aesthetics and Nuisance
The Alki wastewater treatment facility constitutes a
major nuisance in its neighborhood: it emits odors, occu-
pies valuable real estate, and discharges to Puget Sound.
The Alki residents want to get rid of it. Under Alternatives
C and F, the Alki facility would be phased out. But it
would be replaced by a facility in the Duwamish; it_is still
being determined how much of a nuisance a facility in the
Duwamish would be.
Under Alternatives A, B, D, E, G and H, the Alki facil-
ity would remain, a nuisance which is considered adverse,
major, long-term, reversible, local and definite..
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Alternatives and Impacts
Summary
Under Alternative C, combined sewer overflows at Alki
Point and to the Duwamish river would be 97 and 26 percent
controlled; under Alternative D, they are to be controlled
18% at Alki, and not at all in the Duwamish. Alternative
F would reduce CSO's to Alki Beach 97%, but not affect
CSO's to the Duwamish. These are expected to make the
water's visual appearance more appealing. At these locations,
this is considered favorable, minor, long-term, irreversible
and probable.
Sludge truck traffic is as indicated in Table 3-2. Al-
though secondary treatment produces more sludge than primary
treatment, the dewatering facilities provided in Alternatives
D, E, F, G and H significantly reduce the volume and, hence,
the number of truck trips required for ultimate disposal.
Truck traffic would cause some nuisance on residential streets,
and some congestion along an already crowded beach front, but
the impact is considered minor; this topic was mentioned by
few people in the HRPI and Gerhardt Research interviews at
Alki.
There would be some nuisance during construction,
especially at Alki under Alternatives E, G and H, and at
Diagonal Way in Alternative C, and Harbor Avenue under
Alternative F. These impacts would be adverse, minor, short-
term, reversible, local and definite.
TABLE 3-2
Sludge Trucking Traffic (in trucks per day)
ABCDEFGH
Alki 1.7 1.7 0 0.6 0.5 0 0.5 0.5
Duwamish - - 0.3 - - 4.8
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CHAPTER IV
CITIZEN AND AGENCY INVOLVEMENT
The interaction between citizen and agency personnel
(and their consultants) in the Alki area to date has in-
cluded small group and information meetings, community meet-
ings, contacts with civic leaders, and communication with
neighborhood groups (particularly the Alki Community Council
and its task force on sewage treatment plant expansion).
The first series of contacts of Metro's Clear Water
Watch program in the Alki community were made in the spring
of 1976 by the Human Resources Planning Institute (HRPI),
Metro's social and economic consultant. A small group meet-
ing was held with eleven people in attendance. Nine citi-
zens attended a focus group meeting.
The first community meeting in the Alki area was held
at the Alki Community Club on June 9, 1976. Attending were
34 area citizens, representatives of the Metro Council, Metro
staff, Metropolitan Engineers (Metro's facilities planning
consultant), and the Citizens' Water Quality Advisory Com-
mittee (CWQAC). Following a description of PL 92-500 and
the facilities planning process., the panel presented the
"merit" system-wide alternative as well as four alterna-
tives for the Alki plant. Results of small group meetings
and architectural site analysis were also presented and
activities of the CWQAC were described.
The concerns and priorities expressed by the citizens
in attendance included their desire for a voice in the
design process, concern over plant odor, and a desire to
see the plant moved, but not if such a move is much higher
in cost than substantial plant improvements at Alki. Pri-
orities for on-site improvements included odor control,
avoiding removal of houses or the ballfield, construction
additions over the road toward the shore or under the ball-
field, or designing the plant site for multiple use (such
as recreation). Other comments concerned ownership and
options on the ballfield, federal funding limits, and effect
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Citizen and Agency Involvement
of a plant expansion on property values. Because so many
issues were raised, the meeting ended with formation of the
Alki Treatment Plant Advisory Committee, to meet frequently
to study plant alternatives and design criteria and to make
recommendations. Metro staff prepared a summary of the
meeting for those attending and maintains a copy on file in
the Metro offices.
The second community meeting for Alki was held November
18, 1976 at the Alki Congregational Church. Attending were
approximately 75 citizens plus representatives of Metro
Council; various consultants involved in the study; and the
CWQAC. The planning alternatives for Alki and the entire
Metro system ("no action", "legal", and "goal") were pre-
sented along with discussion of architectural concepts and
socioeconomic impacts.
The major issues raised by the citizens included odor
(past, present, and future control), plant expansion (adja-
cent property, architectural treatment), system planning
(local share of federal costs, inflation in possibly in-
evitable secondary treatment costs, compatibility of Duwam-
ish plant with land uses there, accuracy of population pro-
jections, Interbay options, advisability of pursuing illegal
options), combined sewer overflows and storm sewers (health
hazard, location siting, incomplete problem solution by
Forward Thrust program), water quality (effects of storm
water runoff, flushing ability of Puget Sound, heavy metals
control, relative position of Metro as a water quality
leader), and rates (itemizing Metro rates separately, se-
lection of inflation rate). A meeting summary was prepared
by Metro staff, mailed to citizens attending, and maintained
on file in the Metro office.
At the November meeting a representative of the Alki
Task Force of the Alki Community Council presented the com-
mittee Report on. Sewage Treatment Plant Expansion, dated
November 11, 1976. The report unanimously recommended
closing the present facility if it is technically and
economically feasible. If that recommendation is not feasi-
ble, the committee recommended several criteria in conjunc-
tion with any future expansion: restrictions on facility
height, size and function; minimum sludge truck traffic;
odor control; architectural and landscaping features; elim-
ination of further residential property condemnation; clear
breakdowns of capital and operating costs; analysis of plant
impact on beach or ballfield recreational areas; need for
accurate estimate of federal, state and local financing;
and evaluation of technological advances. The citizens in
attendance unanimously approved the Task Force report.
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Citizen and Agency Involvement
A third Clear Water Watch community workshop was held
June 8, 1977 in the conference room of the Center House at
Seattle Center. Among those attending were approximately 14
residents of the Alki area. The discussion centered on
needed improvements at the Alki plant but included topics
of regional concern.
Members of the Alki group feel strongly that the odor
problem at Alki could be resolved at minimal expense, and
that it is Metro's social responsibility to correct this
situation. Participants noted that the Alki plant was
poorly designed and felt that attention should be given to
solving the present problem before addressing long-range
alternatives. Even under Alternatives C and F, which solve
the odor problem by abandoning the Alki plant, odors would
continue through 1985. Residents requested that Metro con-
sider an interim alternative to resolve the current odor
problem. There was also concern over the need to preserve
homes, property values and open land in the neighborhood.
The possibility of improving the ballparks, rather than los-
ing them to a larger treatment plant was mentioned. Citi-
zens also expressed concern over the effects of primary
effluent on Puget Sound. Citizens expressed skepticism
toward Metro's attitude regarding secondary treatment and
the ability of the Sound to safely assimilate primary efflu-
ent. The citizens also questioned the water quality improve-
ments that would be gained merely by extending the Alki out-
fall. A recurring theme among participants was the need for
more communication between citizens and Metro, and for Metro
to trust the ability of the citizens to understand the situ-
ation — when they are provided with all the facts. The
public hearing on the Draft EIS for Alki is planned for
October 27, 1977. A hearing on the Final EIS for system-
wide alternative selection is scheduled for March 1978.
The site-specific comments to date from citizen and
agency involvement in the Alki, Duwamish, and related al-
ternative facilities locations have been considered in de-
veloping this Draft EIS (Volume II) for Alki. Future site-
specific comments will be considered in the Final EIS
(Volume II) for Alki. All regional or system-wide issues
have been or will be handled similarly in the Regional EIS
(Volume I of this series).
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APPENDIX A
REFERENCES
See Regional Analysis EIS, Volume I, for references
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APPENDIX B
ELEMENTS OF THE ENVIRONMENT
WAG 197-10-442 SPECIAL CONSIDERATIONS REGARDING CONTENTS
OF AN EIS ON A NON-PROJECT ACTION. (1) The requirements of
WAG 197-10-440 apply to the contents of a draft EIS on a pro-
posal for a non-project action. Lead agencies, however, have
greater flexibility in their approach to achieving compliance
with the requirements of WAG 197-10-440 in writing an EIS for
non-project actions, because normally less specific details are
known about the proposal and any implementing projects, as well
as the anticipated impacts on the environment.
(2) The lead agency should be alert to the fact that it
is in the development and review of proposals for non-project
actions where the range of alternatives is typically more broad
than that of a proposal for a project action (which is often
narrowed to a specific location and design). The proposal
should be described in a manner which encourages consideration
of a number of alternative methods of accomplishing its
objective. For example, an objective of an agency's pro-
posal should be stated as "the facilitation of the movement
of people from point A to point B" rather than "the widening
of an urban arterial in order to accommodate additional pri-
vately-owned passenger vehicles."
WAG 197-10-444 LIST OF ELEMENTS OF THE ENVIRONMENT.
(1) Every EIS shall have appended to it a list of the elements
of the environment in subsection (2), (3) and (4) of this sec-
tion. The lead agency shall place "N/A" ("not applicable")
next to an item when the proposal, including its indirect
impacts, will not significantly affect the area (or subarea)
of the environment in question._ Items marked "N/A" need
not be mentioned in the body of' the EIS. Subsections (2) and
(3) of this section correspond in subject matter to the
questions contained in the environmental checklist used for
threshold determination, and the questions in the checklist
may be used to interpret this outline listing.
(2) ELEMENTS OF THE PHYSICAL ENVIRONMENT.
(a) Earth.
(i) Geology.
(ii) Soils.
(iii) Topography.
(iv) Unique physical features.
(v) Erosion.
N/A (vi) Accretion/avulsion.
(b) Air.
(i) Air quality.
(ii) Odor.
(iii) Climate.
(c) Water.
N/A (i) Surface water movement.
(ii) Runoff/absorption.
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(iii) Floods.
(iv) Surface water quantity.
(v) Surface water quality.
N/A (vi) Ground water movement.
(vii) Ground water quantity.
N/A (viii) Ground water quality.
N/A (ix) Public water supplies.
(d) Flora.
(i) Numbers or diversity of species.
(ii) Unique species.
(iii) Barriers and/or corridors.
(iv) Agricultural crops.
(e) Fauna.
(i) Numbers or diversity of species.
(ii) Unique species.
(iii) Barriers and/or corridors.
(iv) Fish or wildlife habitat.
(f) Noise.
N/A (g) Light and glare.
(h) Land use.
(i) Natural resources.
(i) Rate of use.
(ii) Nonrenewable resources.
(j) Risk of explosion or hazardous emissions
(3) ELEMENTS OF THE HUMAN ENVIRONMENT.
(a) Population.
N/A (b) Housing.
(c) Transportation/circulation.
(i) Vehicular transportation generated.
N/A (ii) Parking facilities.
N/A (iii) Transportation systems.
N/A (iv) Movement/circulation of people or goods
N/A (v) Waterborne, rail and air traffic.
(vi) Traffic hazards.
(d) Public services.
N/A (i) Fire.
N/A (ii) Police.
N/A (iii) Schools.
(iv) Parks or other recreational facilities.
N/A (v) Maintenance.
N/A (vi) Other governmental services.
(e) Energy.
(i) Amount required.
(ii) Source/availability.
B-2
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(f) Utilities.
(i) Energy.
N/A (ii) Communications.
N/A (iii) Water.
(iv) Sewer.
(v) Storm water.
(vi) Solid waste.
(g) Human health (Not including mental health]_
(h) Aesthetics.
(i) Recreation.
(j) Archeological/historical.
(4) The following additional element shall be covered in
all EISs, either by being discussed or marked "N/A," but shall
not be considered part of the environment for other purposes:
(a) Additional population characteristics.
(i) Distribution by age,sex and ethnic characteristics
of the residents in the geographical area affected by the en-
vironmental impacts of the proposal.
WAG 197-10-446 DRAFT EIS--OPTIONAL ADDITIONAL ELEMENTS--
LIMITATION. Agencies in their guidelines may add to the list
in WAG 197-10-444 additional elements covering social, cultur-
al and/or economic issues. Such additional elements shall be-
come part of the environment for EIS purposes, and not other-
wise. The guidelines of the lead agency shall control the
content of the EIS, even though other agencies with jurisdic-
tion are involved in the proposal. No agency shall prescribe
additional material for an EIS beyond that which is required
or optionally allowed by WAG 197-10-440 and -444, or which is
added to the elements of the environment by the guidelines of
the lead agency pursuant to the authority in this section [see
WAG 197-10-440(14)].
PUBLIC AWARENESS, HEARINGS AND CIRCULATION OF DRAFT EIS
WAG 197-10-450 PUBLIC AWARENESS OF AVAILABILITY OF DRAFT
EIS. (1)Upon publication of the draft EIS, the responsible
official shall list the proposal in the lead agency's "EIS
Available Register" maintained at the agency's SEPA public in-
formation center.
(2) The lead agency is encouraged, but not required, to
use any reasonable method calculated to inform the public of
the availability of the draft EIS and of the procedures for
requesting a public hearing. Examples of such methods are
publication of notice in a newspaper of general circulation in
the county, city or general geographic area where the proposal
is located; notifying private groups that are known to be in-
terested in a certain proposal; contacting news media personnel
and encouraging news coverage; and, placing notices in appro-
priate regional, neighborhood or ethnic periodicals.
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