Boston Harbor
Wastewater
Conveyance System
Volume II
Draft Supplemental Environmental Impact Statement
Appendices
   \
United States Environmental Protection Agency
Region I
J.F.K. Federal Building
Boston, Massachusetts 02203
1988

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Cover photograph taken by Kathleen Kirkpatrick Hull.

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Boston Harbor
Wastewater
Conveyance System
Volume II
Draft Supplemental Environmental Impact Statement
Appendices
Prepared by:
United States Environmental Protection Agency
Region I
J.F.K. Federal Building
Boston, Massachusetts 02203
1988
Technical Assistance by:
Metcalf & Eddy
‘0 Ha,va,C Mill Scuare
Walcefeic Massacnuse
¼ /
IC L R. DELAND Date
Regional Adi inistrator,
U.S. EPA, Region I
This Draft Supplemental Environmental Impact Statement (SEIS)
has been prepared by the U.S. Environmental Protection Agency
(EPA) with assistance from the U.S. Army Corps of Engineers.
This Draft SEIS identifies and evaluates the environmental
impacts of the wastewater conveyance system for Greater
Boston’s wastewater treatment facility in compliance with
Federal and State water pollution control laws.

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DRAY!’ SUPPLEMENTAL ENVI 1 )NHENTAL IMPACT STATEMENT
PROPOSED ACTION: SITING AND EVALUATION OF CONSTRUCTION METHODS
FOR WASTENATER CONVEYANCE SYSTEM FOR SECONDARY
TREA €NT PLANT, BOSTON RARBOR
LOCATION: BOSTON, MASSACHtJSErNIS
DATE: APRIL 1988
SUMMARY OF ACTION: Draft SEIS considers the environmental accepta-
bility of alternative locations for the wastewater
conveyance and outfall systems of the new waste—
water treatment facilities for Boston Harbor. The
Draft SEIS recommends deep rock tunnels for the
inter—island and outfall conduits and a diffuser
located at least seven miles east of Deer Island.
VOLUMES: I. STJPPLEMENTAL ENVIRONMENTAL IMPACT STATEMENT
II. APPENDICES
LEAD AGENCY: U • S • VIW)NHE? TAL P I’ECTION AGENCY, REGION I
JFK Federal Building, Boston, Massachusetts 02203
COOPERATING AGE : U.S. ARMY CORPS OF ENGINEERS
TECHNICAL CONSULTANT: METCALF & EDDY, INC.
Wakefield, Massachusetts
FOR FURTHER INFORMATION: Mr. David ney
Water Management Division
U.S. EPA, Region I
JFK Federal Building
Boston, MA 02203
617—565—4420
FINAL DATE BY WHICH
COMMENTS MUST BE RECEIVED: May 16, 1988

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CONTENTS
This volume contains technical appendices which support the
Boston Harbor Wastewater Conveyance System Draft Supplemental
Environmental Impact Statement (SEIS). The SEIS consists of
three documents:
- Volume I which identifies and evaluates the
environmental impacts of the wastewater conveyance system for
Greater Boston’s wastewater treatment facility. Information
detailed in Volume II is utilized inVoluine I.
— Volume II (this volume) which provides detailed
technical information on:
Physical Oceanography and Water Quality
Marine Geology and Sediment Deposition
Marine Ecosystems
Harbor Resources
Economic Impacts
Screening and Development of Alternatives
Regulatory Conditions
Operational Reliability
— An Executive Summary which outlines impacts and the
recommended plan.

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TABLE OF CONTENTS
Page
LIST OF TABLES
LIST OF FIGURES
APPENDIX A - PHYSICAL OCEANOGRAPHY AND WATER QUALITY FIGURES
A.1 Introduction A-i
A.2 Existing Conditions A-2
A.2.1 Physical Oceanography A-2
A.2.1.1 Processes and Controlling Parameters A-2
A.2.1.2 Data Sources A-5
A.2.1.3 Tides A-i2
A.2.1. 1 4 Currents A-15
A.2.1.5 Stratification A _2Z 1
A.2.2 Water Quality A-25
A.2.2.1 Constituents and Criteria A-25
A.2.2.2 Dissolved Oxygen A-29
A.2.2.3 pH
A.2.2. 1 4 Suspended Solids A-3 1 1
A.2.2.5 Toxic Chemicals A-35
A.3 Water Quality Consequences of Alternatives A-39
A.3.i Constituents A-39
A.3.2 Loadings A-39
A.3.3 Transport Processes A- 1 12
A.3. 1 4 Physico-Blo—Chemical Processes A-43
A.3.5 Nearfield Dilution Modeling A- 6
A.3.5.1 Model A- 1 46
A.3.5.2 Approach A-’48
A.3.5.3 Results A-51
A.3.6 Farfield Modeling A-51
A.3.6.i Purpose A-51
A.3.6.2 Models and Methodologies A-53
A.3.6.3 Single Constituents A-58
A.3.6. 1 Dissolved Oxygen A-63
A.3.6.5 Sedimentation A-6’4
A.3.7 Shoreline Impact Analyses A-67
A.3.7.1 Concerns A-67
A.3.7.2 Model and Methodology A-70
A.3.7.3 Results A-71
A.3.8 Criteria Compliance Evaluation A-71
A.3.8.i Dissolved Oxygen A-71
A.3.8.2 pH A-78
A/3/8/3 Mixing Zone Criteria A-79
Attachment A.a Monthly Averaged Currents from MWRA Program
Attachment A.b Tidal Ellipses Determined from MWRA Current
Measurements
1

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TABLE OF CONTENTS (Continued)
Net Drifts Computed from MWRA Current
Measurements
Longitudinal Stratification Profiles
Single Constituents Farfield Contours
Dissolved Oxygen Farfield Contours
Sedimentation Rate Contours
Farfield Sediment Deposition Rates
APPENDIX B - MARINE GEOLOGY AND SEDIMENT DISPOSITION
B.1 Introduction
B.2 Existing Condition
B.2.i Geological Setting
B.2.2 Bottom Sediment Distribution
B.2.3 Depositional Trends in Massachusetts Bay
B.2.1i Sedimentation Rates
B.2.LI.1 Massachusetts Bay
B.2. 1 L2 Boston Harbor
B.2.’L3 Summary of Deposition Rates
B.2.5 Sediment Chemistry
B.2.5.1 PCB Compounds
B.2.5.2 Metals
B.2.5.3 Pesticides
B.2.5.LI Acid Based Neutrals
B.2.5.5 Bioturbation Mixing Depth
B.3 Sediment Quality Impacts
B.3.1 Introduction
B.3.2 Effluent
B.3.3 Sediment
B.3.3. 1
B.3.3.2
B.3.3.3
Particulate Deposition Rates
Chemistry Prediction Methods
Effluent Particulate Chemical Deposition
Background Particulate Chemical Deposition
Bioturbation and Resuspension of
Bottom Sediment
B.3.LI Simulation of Sediment Impacts
B.3.5 Summary of Predicted Sediment Concentrations
APPENDIX C - MARINE ECOSYSTEMS
Benthic Epifauna
C.i.2.1. 1 Epifaunal Species Composition
and Abundance
C.i.2.2 Benthic Infauna C-i
C.1.2.2.1 Physical and Chemical Conditions C-i
C.i.2.2.2 Infaunal Species Composition C-9
Attachment A.c
Attachment
Attachment
Attachment
Attachment
Attachment
A.d
A.e
A.f
A.g
A.h
Page
B-i
B-3
B-3
B- 4
B-5
B-6
B-6
B-i
B-8
B-9
B-12
B-12
B-i LI
B-i LI
B iLl
B- 15
B- 15
B- 16
B- 16
B- 16
B-17
B-17
B- 18
B-20
C-i
C-3
C-3
C-3
C.1 Affected Environment
C.i.1 Overview
C. 1 .2 Macrobenthos
C. 1.2.1
11

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TABLE OF CONTENTS (Continued)
C.1.2.2.3 Species Densities
C.L2.2. 1 4 Temporal Patterns
C.1.2.2.5 Evidence of Stress
Benthic Communities in Boston Harbor
Phytoplankton
C.1.3.1.2 General
C.1.3.1.3 Massachusetts Bay Studies
C.1.3.2 Zooplankton -
C.1.3.2.1 General
C. 1.3.2.2 Ichthyoplankton
Plankton Communities in Boston Harbor
General
Massachusetts Bay
Fish Communities in Boston Harbor
Demersal Fish and Epibenthic Shellfish
Contamination
C.1.5 Marine Mammals
C.1.5.1 Whales
C.1.5.2 Seals
C.1.6 Marine Turtles
C.1.7 Seabirds
APPENDIX D - HARBOR RESOURCES
D.1 Introduction
D.2 Description of the Project
D.2.1 Construction of Facilities
D.2.2 Description of the Water Transportation Program
D.2.2.1 Bulk Cargo
D.2.2.2 Construction and Operation Cargo
D.2.2.3 Personnel Transport
D.2.2. 1 4 Excavated Material
D.2.2.5 Diffuser Construction Personnel
and Materials
D.2.3 Project Related Marine Traffic
D.3 Affected Harbor Resources Environment
D.3.1 Overview of Existing Harbor Resources
D.3.1.1 Navigation
D.3.1.2 Shipping and Water Transportation
D.3.1.3 Commercial Fishing
D.3.1. L I Recreation Areas and Facilities
D.3.1.5 Sensitive and Protected Areas
D.3.1.5.1 Bathing Beaches
D.3.1.5.2 Shellfish Beds
D.3.1.5.3 Marine Research Facilities
C. 1.2.3
C.1.3 Plankton
C. 1.3.1
C.1.3.3
C.1.LI Fish
C. 1 .LL 1
C.1.q.2
C.1. 1 L3
C. 1 . 14.1 1
Page
C-12
C- 12
C- 17
C- 17
C- 18
C- 18
C- 18
C-20
C-27
C-27
C-28
C-28
C-28
C-30
C-33
C_141
C_143
C- 47
C_L 17
C-50
C-50
C-5O
D-1
D-1
D-1
D- 1 1
D-7
D-8
D-9
D-9
D-9
D-1O
D- 13
D- iLl
D- iLl
D- 16
D-20
D-25
D-26
D-26
D-26
D- 30
1.11

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TABLE OF CONTENTS (Continued)
Page
D.3.l.5.LI Estuarine and Submerged D-30
Aquatic Vegetation
D.3.i.5.5 Sanctuaries and Areas of D-30
Critical Environmental Concern
D.3.1.6 Cultural and Archaeological Resources D-31
D. 4 Environmental Consequences of the Project D-3 4
D.L$.l Navigation D-3i4
D.LL.2 Shipping and Water Transportation D-36
D. 1 4.3 Commercial Fishing D-39
D.1L14 Recreation D- 4i
D.ZL.5 Sensitive and Protected Areas D _Z 12
D.i4.6 Cultural and Archaelogical Resources D- 1 12
D. 1 L7 Conclusion D- 1 13
APPENDIX E - ECONOMIC IMPACTS
E.l MWRA Current Revenue System E-i
E.2 Financial Impacts of the Outfall Alternatives E-2
E.2.1 Capital Expenditures E-2
E.2.2 Operating Expenditures E-8
E.2.3 Revenue Requirements E-8
E.3 Impact on Member Communities E-9
E.3.l Boston E-12
E.3.2 Needham E-13
E.14 Comparison with National Average E-15
E.5 Impacts on Users E-17
APPENDIX F - SCREENING AND DEVELOPMENT OF ALTERNATIVES
F.l Definition of No Action F-i
F.2 Diffuser Location Alternatives F-3
F.2.l Screening Process F-3
F.2.1.i First Secondary Effluent Site F- 4
Screening Step: Landward Boundary
F.2.i.1.i Landward Boundary F LI
Screening Criteria
F.2.i.i.2 Application of Criteria F-6
F.2.1.i.3 Summary F-8
F.2.1.2 Second Secondary Effluent F-12
Screening Step: Eastern Boundary
F.2.1.2.1 Screening Criteria F-i2
F.2.i.2.2 Application of Criteria F-16
F.2.1.2.3 Summary F-22
F.2.i.3 Final Screening Step: Alternative F-26
Discharge Locations
F.2.l.3.i Site Designation F-26
F.2.1.1l Interim Discharge Screening Criteria F-27
F.2.1.14.1 Screening Criteria F-27
iv

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TABLE OF CONTENTS (Continued)
Environmental
Engineering Feasibility
Cost
Materials Disposal
Institutional
Harbor Resources
F-35
F-35
F -36
F-36
F-37
F-38
F-38
F-38
F-39
F-39
F-L O
F- 4O
F_LIO
F- Ill
F- I l
F-Ill
F-Il 1
F- 1 12
F- 1 12
F_L 12
F- I l2
F- 1 42
F- 1 43
F- 1 46
F-L 16
F- 1 47
F-U7
F- 1 47
F- I l8
F-50
F-50
F-5 1
F-5 1
F-5 1
F-5 1
F-52
F-53
F-53
F-53
Page
F-29
F-3U
F-3 1 4
Alternatives
F.2.1. 1 t.2 Application of Criteria
F.2.1.Zl.3 Summary
F.2.2 Description of Discharge Location
for Detailed Evaluation
F.2.3 Criteria for Detailed Evaluation
F.2.3.1 Water Quality
F.2.3.2 Sediment Quality
F.2.3.3 Marine Ecosystems
F.2.3.Zl Harbor Resources
F.2.3.5 Public Health
F.2.3.6 Engineering Feasibility
F.2.3.7 Cost
F.2.3.8 Materials Disposal
F.2.3.9 Institutional
F.3 Effluent Conveyance Mode
F.3.1 Screening Process
F.3.1.1 Description of Alternatives for Screening
Analysis
F.3.1.2 Screening Criteria
F.3.1.2.1 Marine Ecosystems Impacts
F.3.1.2.2 Impacts on Resources
F.3.1.2.3 Disposal of Dredged or
Tunnelled Material
F.3.1.2. 1 l Constructibility
F.3. 1.2.5 Institutional Constraints
F.3.1.2.6 Cost
F.3.1.3 Application of Criteria
F.3.1.3.1 Marine Ecosystems Impacts
F.3.1.3.2 Impacts on Resources
F.3.1.3.3 Disposal of Dredged or
Tunnelled Material
F.3.1.3.Il Constructibility
F.3.1.3.5 Institutional Constraints
F.3.1.3.6 Cost
F.3.1.Il Summary
F.3.2 Description of Outfall Conduit Alternative for
Detailed Evaluation
F.3.3 Criteria for Detailed Evaluation
F.3.3.1
F.3.3.2
F.3.3.3
F.3.3.’l
F.3.3.5
F.3.3.6
F.LI Diffuser Types
F. 4.1 Screening Process
F.IL1.1 Description of Alternatives for Screening
Analysis
V

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TABLE OF CONTENTS (Continued)
Page
F. L1.2 Screening Criteria F—56
F.LL1.2.1 Marine Ecosystems Impacts F-56
F.1I.1.2.2 Impacts on Resources F-56
F.14.1.2.3 Constructibility F-56
F.LL1.2.LI Operational Complexity F-56
F. 4.1.2.5 Institutional Constraints F-58
F.IL1.3 Application of Criteria F-58
F.LI.1.3.1 Marine Ecosystems Impacts F-58
F.LL1.3.2 Impacts on Resources F-59
F. 4.1.3.3 Constructibility F-59
F.LL1.3.14 Operational Complexity F-59
F.LI.1.3.5 Institutional Constraints F—60
F.14.1.LI Summary F-60
F.Zi.2 Description of Diffuser Alternatives for Detailed F-60
Evaluation
F.LL.3 Criteria for Detailed Evaluation F-60
F.LI.3.1 Environmental F-62
F.LI.3.2 Engineering Feasibility F-62
F.Z .3.3 Materials Disposal F-62
Institutional F-62
F.Lt.3.5 Marine Ecosystem F-63
F.LL3.6 Harbor Resources F-63
F.5 Inter-Island Conveyance Mode F _61
F.5.1 Screening Process F-6 1
F.5.1.1 Description of Alternatives for Screening F_611
Analysis
F.5.1.2 Screening Criteria F—65
F.5.1.2.1 Marine Ecosystems Impacts F-65
F.5.1.2.2 Impacts on Resources F-65
F.5.1.2.3 Disposal of Dredged or F-66
Tunnelled Material
F.5.1.2. 4 Constructibility F—66
F.5.1.2.5 Institutional Constraints F-66
F.5.1.2.6 Cost F-66
F.5.1.3 Application of Criteria F-66
F.5.1.3.1 Marine Ecosystems Impacts F-66
F.5.1.3.2 Impacts on Resources F—66
F.5.1.3.3 Disposal of Dredged or F—68
Tunnelled Material
F.5.1.3.LI Constructibility F—68
F.5.1.3.5 Institutional Constraints F-69
F.5.1.3.6 Cost F-69
F.5.1.14 Sununary F-69
F.5.2 Description of Inter-Island Conduit Alternative F-TI
for Detailed Evaluation
F.5.3 Criteria for Detailed Evaluation F-71
F.5.3.1 Environmental F-71
F.5.3.2 Engineering Feasibility F-75
P.5.3.3 Cost F-76
F.5.3.l Materials Disposal F—76
vi

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TABLE OF CONTENTS (Continued)
F.5. 1 4.5 Institutional
F.5.3.6 Harbor Resources
APPENDIX G - REGULATORY CONDITIONS
G.1 Introduction
G.2 Areas of Decision
G.2.1 Outfall Location
G.2.2 Effluent Conveyance Mode and Route
G.2.3 Diffuser Type
G.2.1I Inter—Island Conveyance Mode and Route
G.3 Federal Laws Affecting Areas of Decision
G.3.1 National Environmental Policy Act
G.3.2 Federal Water Pollution Control Act
G.3.3 Rivers and Harbors Act of 1899
G.3.LI Marine Protection, Research and Sanctuaries Act
G.3.5 Coastal Zone Management Act of 1972
G.3.6 Fish and Wildlife Coordination Act
G.3.7 Endangered Species Act of 1973
G.3.8 Marine Mammal Protection Act
G.3.9 National Historic Preservation Act of 1966
G.3.1O Federal Laws Affecting Upland Disposal of’
Dredged Material
Executive Order No. 11990: Protection
Executive Order No. 11988: Floodplain
Laws Affecting Areas of Decision
Massachusetts Environmental Policy Act
Wetlands Protection Act
Certification for Dredging, Dredged Material
Disposal and Filling in Waters
Massachusetts Clean Water Act
Coastal Zone Management Program
Massachusetts Surface Water Quality Standards
and Discharge Permits
Waterways License and Dredging Permits
Massachusetts Division of Marine Fisheries
Natural Heritage and Endangered Species Program
Massachusetts Laws Affecting Upland Disposal
of Dredged Material
G.5 Conclusion G-23
H.1 Introduction
H.1.1 Recommended Plan
H.1.2 Operation During Construction
H.1.3 Flows to Treatment Plant
H.2 Probable Operating Scenarios
Page
F-76
F-76
G-1
G- 1
G-1
G-2
G-2
G-3
G- L I
G- L I
G-5
G-9
G-9
G-1O
G-1 1
G-11
G-12
G-12
G- 13
G- iLl
G- iLl
G- 15
G- 15
G- 16
G- 17
G- 17
G- 17
G- 18
G-22
G-22
G-22
G-23
G.3. ii
G.3. 12
G.Ll State
G.4. 1
G.4.2
G. 1 L3
G.ILLI
G.LI.5
G.’ l .6
G. L l.7
G.LI.8
G.1L9
G.14. 10
of Wetlands
Management
APPENDIX H — OPERATIONAL RELIABILITY
H-i
H-i
H-LI
H-LI
H-6
vii

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TABLE OF CONTENTS (Continued)
Page
H.2.l Redundancy H-7
H.2.l.l Mechanical Equipment H-7
H.2.1.2 Tanks H-il
H.2.l.3 Disinfection System H—li
H.2.2 Power H-13
H.2.2.l Recommended Plan H-1 1 4
H.2.2.2 Essential Power Requirements H-16
H.2.3 Other Considerations H- 18
H.2.li Operating Scenarios Considered H-20
H.2. 1 l.l Primary Treatment Phase H—20
H.2. 1 4.2 Secondary Treatment Phase H-21
H.3 Effluent Characteristics H—23
H.3.l Conventional Pollutants H-23
H.3.2 Non-Convential Pollutants H-27
H.3.2.l Influent Loadings H-27
H.3.2.2 Removal Rates H-28
H.3.2.3 Sensitivity Analysis H-33
H.3.3 Probable Operating Scenarios Effluent H-3 1 4
Characteristics
H.3.3.l Primary Treatment Phase H-3 1 4
H.3.3.2 Secondary Treatment Phase H-35
v iii

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LIST OF TABLES
APPENDIX A - PHYSICAL OCEANOGRAPHY AND WATER QUALITY FIGURES
Table Page
A.2.1 Amplitude and Lags of M2 Components of A-15
Water Level Measurements
A.2.2 Statistics of 1987 MWRA Meter Measurements A-18
A.2.3 Commonwealth of Massachusetts.Surface Water A-26
Quality Standards - Minimum Criteria Application
To All Waters -
A.2.L$ Commonwealth of Massachusetts Surface Water A-27
Quality Standards — Additional Criteria for Marine
Class SA Waters
A.2.5 Salt Water Aquatic Life and Human Health A-30
Water Quality Criteria A-31
A.2.6 Metal Concentration in Water Column at Two A-37
Stations in Massachusetts Bay
A.2.7 Concentrations of PCB in Seawater Collected at Two A-38
Stations in Massachusetts Bay in April, 1987
A.3.1 Constituents Loadings A- l b
A.3.2 Distribution of Discharged Solids Fall Velocities A- 1 45
A.3.3 Decay Rates of Chemical Constituents in Effluent A- 1 47
A.3.lb Nearfield Simulation Conditions A-50
A.3.5 Nearfield Dilutions A-51
A.3.6 Background Buildup (ng/l) For Base Loading A-62
(200 mg/i)
A.3.7 Maximum Dissolved Oxygen Deficits (mg/i) A-6 1 4
A.3.8 Maximum Shoreline Concentrations A-7 l b
A.3.9 Minimum Dissolved Oxygen Concentrations (mg/i) in A-75
the Water Column Based on 8.0 mg/i Ambient
Concentration
A.3.1O Sediment Deposition Rates, Rd (g/m 2 /day) and A-77
Resuspension Oxygen Demands, RDOD (mg/i)
ix

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LIST OF TABLES (Continued)
Table Page
A.3.11 Minimum Water Column Dissolved Oxygen Concentrations A-77
During Resuspension Event
A.3.12 Effluent Mass Fluxes (ug/sec) From Other Sources A-80
A.3.13 Aquatic Life Toxicity Criteria Compliance for Site 2 A-83
A.3.1 1 4 Aquatic Life Toxicity Criteria Compliance for Site k A_SI!
A.3.15 Aquatic Life Toxicity Criteria Compliance for Site 5 A-Bk
A.3.16 Human Health Criteria Compliance for Site 2 A-87
A.3.17 Human Health Criteria Compliance for Site I! A-88
A.3.18 Human Health Criteria Compliance for Site 5 A-89
A.3.19 Summary of Predicted Water Quality Criteria A-90
Exceedances
APPENDIX B - MARINE GEOLOGY AND SEDIMENT DEPOSITION
B.2.a Summary of Reported Massachusetts Bay and Boston B-9
Harbor Sedimentation Rates
B.2.b Contaminants for Assessment of Sediment Deposition B-1O
Impacts
B.2.c Summary of Sediment PCB Measurements B-12
B.2.d Summary of Sediment Metals Measurements B-13
B.3.a Summary of Site To Site Comparision of Sediment B-21
B.3.b Effluent Sedimentation at Site 2 Under Secondary B-22
Treatment and Non—stratified Conditions Over 5 Years
B.3.b (Continued) Input Concentrations to Predict Bottom B-23
Sediment Concentrations at Site 2 Under Secondary
Treatment and Non-stratified Conditions Over 5 Years
for Selected Compounds
B.3.b (Continued) Projected Bottom Sediment Concentrations B-23
( ig/g) at Site 2 Under Secondary Treatment and
Non-stratified Conditions Over 5 Years for Selected
Compounds
x

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LIST OF TABLES (Continued)
Table Page
B.3.b (Continued) Effluent Sedimentation at Site i Under B-2 1 4
Secondary Treatment and Non-stratified Conditions
Over 5 Years
B.3.b (Continued) Input Concentrations to Predict Bottom B-25
Sediment Concentrations at Site 4 Under Secondary
Treatment and Non—stratified Conditions Over 5 Years
for Selected Compounds
B.3.b (Continued) Projected Bottom Sediment Concentrations B-25
(ug/g) at Site J4 Under Secondary Treatment and
Non-stratified Conditions Over 5 Years for Selected
Compounds
B.3.b (Continued) Effluent Sedimentation at Site 5 Under B-26
Secondary Treatment and Non-stratified Conditions
Over 5 Years
B.3.b (Continued) Input Concentrations to Predict Bottom B—27
Sediment Concentrations at Site 5 Under Secondary
Treatment and Non-stratified Conditions Over 5 Years
for Selected Compounds
B.3.b (Continued) Projected Bottom Sediment Concentrations B-27
(iig/g) at Site 5 Under Secondary Treatment and Non-
stratified Conditions Over 5 Years for Selected
Compounds
B.3.c Effluent Sedimentation at Site 2 Under Primary B-28
Treatment and Non-stratified Conditions Over 5 Years
B.3.c (Continued) Input Concentrations to Predict Bottom B-29
Sediment Concentrations at Site 2 Under Primary
Treatment and Non—stratified Conditions Over 5 Years
B.3.c (Continued) Projected Bottom Sediment Concentrations B-3O
at (iig/g) Site 2 Under Primary Treatment and Non-
stratified Conditions Over 5 Years
B.3.c (Continued) Effluent Sedimentation at Site LI Under B-31
Primary Treatment and Non-stratified Conditions Over
5 Years
B.3.c (Continued) Input Concentrations to Predict Bottom B-32
Sediment Concentrations at Site LI Under Primary
Treatment and Non-stratified Conditions Over 5 Years
B.3.c (Continued) Projected Bottom Sediment Concentrations B-33
( g/g) at Site LI Under Primary Treatment and Non-
stratified Conditions Over 5 Years
xi

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LIST OF TABLES (Continued)
Table Page
B.3.c (Continued) Effluent Sedimentation at Site 5 Under B _3 14
Primary Treatment and Non-stratified Conditions Over
5 Years
B.3.c (Continued) Input Concentrations to Predict Bottom B-35
Sediment Concentrations at Site 5 Under Primary
Treatment and Non—stratified Conditions Over 5 Years
B.3.c (Continued) Projected Bottom Sediment Concentrations B-36
(ig/g) at Site 5 Under Primary Treatment and
Non-stratified Conditions Over 5 Years
B.3.d Effluent Sedimentation at Site 2 Under Primary B-37
Treatment and Stratified Conditions Over 6 Months
B.3.d (Continued) Input Concentrations to Predict Bottom B-38
Sediment Concentrations at Site 2 Under Primary
Treatment and Stratified Conditions Over 6 Months
B.3.d (Continued) Projected Bottom Sediment Concentrations B-39
(ug/g) at Site 2 Under Primary Treatment and
Stratified Conditions Over 6 Months
B.3.d (Continued) Effluent Sedimentation at Site 14 Under B- 1 40
Primary Treatment and Stratified Conditions Over
6 Months
B.3.d (Continued) Input Concentrations to Predict B— 1 41
Bottom Sediment Concentrations at Site 14 Under
Primary Treatment and Stratified Conditions
Over 6 months
B.3.d (Continued) Projected Bottom Sediment Concentrations B- 1 42
(pg/g) at Site 14 Under Primary Treatment and
Stratified Conditions Over 6 Months
B.3.d (Continued) Effluent Sedimentation at Site 5 Under B- 1 43
Primary Treatment and Stratified Conditions Over
6 Months
B.3.d (Continued) Input Concentrations to Predict Bottom B_ 1414
Sediment Concentrations at Site 5 Under Primary
Treatment and Stratified Conditions Over 6 Months
B.3.d (Continued) Projected Bottom Sediment Concentrations B- 1 45
( ig/g) at Site 5 (Soft—bottom) Under Primary Treatment
and Stratified Conditions Over 6 Months
xii

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LIST OF TABLES (Continued)
Table Page
B.3.d (Continued) Projected Bottom Sediment Concentrations B- 46
(ug/g) at Site 5 (Hard-bottom) Under Treatment and
Stratified Conditions Over 6 Months
APPENDIX C - MARINE ECOSYSTEMS
C.i.a Summary of’ Marine Ecosystem Surveys C-i
C.1.b Summary of’ General Bottom Types and Epifaunal C-5
Assemblages
C.i.c General Characterization of Nearshore and C-a
Farshore Parameters in Massachusetts Bay
C.l.d Percent Total Fauna by Cruise for Dominant C-1O
Species at 1987 MWRA Sites
C.1.e Benthic Community Parameters for Each MWRA Site C—12
Sampled Temporally, All Replicates Combined
C.1.f Results of One-Way ANOVA to Compare Loge C-13
Densities Obtained During Three Cruises
for Five Massachusetts Bay Stations
C.1.g Results of One-Way ANOVA to Compare Loge C_iLl
Densities of Four Dominant Species at
Four Selected Massachusetts Bay Stations
Sampled Over Three Cruises
C.1.h Seasonal Occurrence of the More Common Forms C-29
of Fish Eggs (E) and/or Larvae (L) Identified
by NMFS in Cape Cod and Massachusetts Bay Neustron
C.1.i Seasonal Migration Characteristics of Some Important C-32
Fish Species
C.1.j Summary of Fish Distribution and Life Histories C—34
C.1.k Average Abundance Per Tow Per Season of C-38
Fish Caught by NMFS Bottom Trawl Surveys 19614 1971
in Massachusetts Bay
C.1.l Average Abundance Per Tow of Demersal Fish Collected C-39
by the Massachusetts Division of Marine Fisheries
in Spring (May) and Fall (September) Bottom Trawls
in Massachusetts Bay from 1978 through 1986
x lii

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LIST OF TABLES (Continued)
Table Page
C.1.m Average Per Tow of Selected Epibenthic Shellfish C-142
Collected by the Massachusetts Division of Marine
Fisheries in Spring (May) and Fall (September) Bottom
Trawls in Massachusetts Bay from 1978 through 1986
C.1.n Summary of PCB Data on Animal Tissues in Boston C_115
Harbor and Massachusetts Bay
C.1.o PAH Concentrations in Crabs (ng/g dry weight) C- 1 46
C.1.p Summary of Whale Distribution and Abundance in C_1 18
the Western Portion of the North Atlantic Ocean
C.1.q Pinniped Species in the Gulf of Maine C-Si
C.1.r Summary of Dominant Seabird Characteristics C-53
APPENDIX D - HARBOR RESOURCES
D.2.a Water Transportation Program D-6
D.2.b Water Transportation Program - Trips/Day D-il
D.3.a Historical Record of Trips and Drafts of D-17
Vessels (Inbound Only) Using the Port of
Boston
D.3.b Comparative Statement of Commerce, Boston D-19
Harbor, Massachusetts
D.3.c Boston Harbor Islands State Park D-29
D. 1 4.a Comparison of Harbor Resources Impacts for D _LI I
Each Diffuser Site
APPENDIX E - ECONOMIC IMPACTS
E.2.a Summary of Selected Outfall Alternatives E-3
E.2.b MWRA Construction Cost Analysis, Inflated Dollar E-5
Cash Flow & Grant Projection, Site 2
Outfall Alternative
xiv

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LIST OF TABLES (Continued)
Table Page
E.2.c MWRA Construction Cost Analysis, Inflated Dollar E-6
Cash Flow & Grant Projection, Site LI
Outfall Alternative
E.2.d MWRA Construction Cost Analysis,Inflated Dollar E-7
Cash Flow & Grant Projection, Site 5
Outfall Alternative
E.2.e Comparison of Capital Cash Flow and Annual E-1O
Revenue Requirements for Each Outfall -
Alternative, Inflated Dollars
E.3.a Summary of Annual Sewer Use Charges for the Outfall E-1LI
Alternatives, Boston
E.3.b Summary of Annual Sewer Charges for the Outfall E-.16
Alternatives, Needham
E.1 Boston Water and Sewer Commission Inflated Dollar E-21
Expense Projections for Site 2 Outfall Alternative
E.2 Projected BWSC Sewer Rates and Financial Impacts E-22
Site 2 Outfall Alternative
E.3 Boston Water and Sewer Commission Inflated Dollar E-23
Expense Projections for Site LI Outfall Alternative
E.LI Projected BWSC Sewer Rates and Financial Impacts
Site LI Outfall Alternative
E.5 Boston Water and Sewer Commission Inflated Dollar E-25
Expense Projections for Site 5 Outfall Alternative
E.6 Projected BWSC Sewer Rates and Financial Impacts E—26
Site 5 Outfall Alternative
E.7 Town of Needham Projected Expenses Site 2 E-28
Outfall Alternative
E.8 Project Needham Sewer Rates and Financial Impacts E-29
Site 2 Outfall Alternative
E.9 Town of Needhain Projected Expenses Site LI E-30
Outfall Alternatives
E.1O Projected Needham Sewer Rates and Financial Impacts E-31
Site LI Outfall Alternative
xv

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LIST OF TABLES (Continued)
Table Page
E.11 Town of Needham Projected Expenses Site 5 E-32
Outfall Alternative
E.12 Projected Needhaxn Sewer Rates and Financial Impacts E-33
Site 5 Outfall Alternative
APPENDIX F - SCREENING AND DEVELOPMENT OF ALTERNATIVES
F.2.a Summary of Diffuser Characteristics and Costs
F.2.b Dilutions of Background Concentrations of Contaminants F-18
F.2.c Summary of’ Secondary Effluent Constituents Which are F-21
Expected to Exceed EPA Water Quality Criteria
Concentrations at the Edge of the Mixing Zone
F.2.d Site Screening Criteria Breakpoint Locations F-2 1 4
F.2.e Summary of Primary Effluent Constituents Which F-31
are Expected to Exceed EPA Water Quality Criteria
Concentrations at the Edge of the Mixing Zone
F.2.f Predictions of Distances, Excursion Times and F—32
Subsequent Dilutions at Shoreline Areas for
Extreme Events
F.2.g Predicted Percentages of Effluent Concentration F-33
at the Winthrop, Hull and Nahant Shorelines
F.3.a Construction Costs of the Alternative Outfall Systems
F.3.b Summary of Effluent Conveyance Screening F- I9
F. 1 4.a Summary of Diffuser Type Screening F—61
F.5.a Summary of Inter-Island Conveyance System Alternatives F-70
F.5.b Costs of the South System Pumping Station F-70
F.5.c Summary of Inter-Island Conveyance Mode Screening F-72
xvi

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LIST OF TABLES (Continued)
Table Page
APPENDIX G - REGULATORY CONDITIONS
G. 1 4.a Commonwealth of Massachusetts: Surface Water G-19
Quality Standards for Class SA Waters
G.5.a Federal Laws, Regulations and Guidelines and G-2 1 4
Their Applicability to the Alternatives
G.5.b Massachusetts Laws, Regulations and Guidelines G—25
and Their Applicability to the Alternatives
APPENDIX H - OPERATIONAL RELIABILITY
H.2.a Summary of Recommended Treatment Plant Processes H—8
at Deer Island, Provision for Standby Units
H.2.b Daily Demand for Purchased Sodium Hypochlorite H-12
H.2.c Preliminary Power Needs of Secondary Treatment H-15
Facilities Plan
H.2.d Essential Power Requirements H—17
H.2.e Comparison of Pollutant Inhibitory Concentration H-19
H.3.a Year 1999, Projected Primary Effluent Conventional H-2 1 1
Pollutants
H.3.b Year 2020, Projected Primary Effluent Conventional H-25
Pollutants
H.3.c Projected Plant Effluent Conventional Pollutants, H-26
Year 2020
H.3.d Influent Loadings of Non—Conventional Pollutants H-29
H.3.e Comparison of Removal Efficiencies of Non-Conventional H-31
Pollutants
H.3.f Year 1999, Projected Primary Effluent Conventional H-35
Pollutants
H.3.g Non—Conventional Pollutant Effluent Concentrations after H-36
Primary Treatment, Year 1999, Average Flow Conditions
xvii

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LIST OF TABLES (Continued)
Table Page
H.3.h Non-Conventional Pollutant Effluent Concentrations, H-37
Primary Treatment, Year 1999, Maximum Loading
Conditions on Storm Day
H.3.i Conventional Pollutant Effluent Concentrations H-38
for up to 1,080 mgd, Secondary Treatment, Year 2020
H.3.j Non-Conventional Pollutant Effluent Concentrations, H_hO
After Secondary Treatment, Year 2020
H.3.k Non-Conventional Pollutant Effluent Concentrations H-hi
After Secondary Treatment, Year 2020, Maximum
Loading Conditions
H.3.l Non—Conventional Pollutant Effluent Concentrations, H- 1 42
After Secondary Treatment, Year 2020, Maximum Loading
Conditions
H.3.m Conventional Pollutant Loadings, Mixed H- 1 43
Primary-Secondary Effluent, Year 2020
H.3.n Non-Conventional Pollutants, Mixed Primary—Secondary H_L I
Effluent, Year 2020, Maximum Loading Conditions
H.3.o Conventional Pollutant Effluent Characteristics H- 1 45
for Mixed Primary-Secondary Effluent, Year 2020
H.1 Comparison of Removal Rates for Metals, Primary H- 1 48
Treatment
H.2 Comparison of Removal Rates for Metals, Secondary H-hg
Treatment
H.3 Comparison of Removal Rates for Acid Base Neutrals, H-SO
Primary Treatment
H.hi Comparison of Removal Rates for Acid Base Neutrals, H-51
Secondary Treatment
H.5 Comparison of Removal Rates for Volatile Organics, H-52
Primary Treatment
H.6 Comparison of Removal Rates for Volatile Organics, H-53
Secondary Treatment
xviii

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LIST OF TABLES (Continued)
Table Page
H.7 Comparison of Removal Rates for Pesticides and PCB, H_5L
Primary Treatment
H.8 Comparison of Removal Rates for Pesticides and PCB, H-55
Secondary Treatment
xix

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LIST OF FIGURES
APPENDIX A - PHYSICAL OCEANOGRAPHY AND WATER QUALITY
Figure Page
A.2.1 Schematic Effluent Plume in the Nearfield A-3
A.2.2 Location of MWRA Current Meter Stations in Relation A-9
to Alternative Diffuser Sites
A.2.3 Coverage of MWRA 1987 Field Program A-1O
A.2.LI Locations of MWRA Survey Transects A-li
A.2.5 Water Level Measurements at Provincetown, Gloucester A- 13
and Their Difference
A.2.6 Harmonic Analysis of Provincetown Tidal Elevations A _ 114
A.2.7 Filtered Water Levels at Provincetown, Gloucester and A- 16
Their Difference
A.2.8 Magnitude-Direction Scatter Plot for Station 2, A-19
August 1987
A.2.9 Magnitude-Direction Scatter Plot for Station I, A-20
August 1987
A.2.1O Magnitude-Direction Scatter Plot for Station 5, A-21
August 1987
A.2.11 Harmonic Analysis of Currents at Station 5U, A-22
August (East-West Component)
A.2.12 Water Quality Measurements at Station 3U During A-33
Summer 1987 (Shows Low Dissolved Oxygen Recorded
on June 6, 1987)
A.2.13 Locations of the Suspended Solids, Metals and A-36
PCB Sampling Stations
A.3.1 Model Grid for Unstratified Conditions A-55
A.3.2 Model Grid for Stratified Conditions A-56
A.3.3 Calculated Farfield Concentrations (mg/i) For Base A-60
Loading (200 mg/see)
A.3. 1 Calculated Farfield Concentrations (mg/i) For Base A-61
Loading (200 mg/see)
xx

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LIST OF FIGURES (Continued)
ATTACHMENT A.b - TIDAL ELLIPSES
MEASUREMENTS
Tidal Ellipses at MWRA
Tidal Ellipses at MWRA
Tidal Ellipses at MWRA
Tidal Ellipses at MWRA
Tidal Ellipses at MWRA
Tidal Ellipses at MWRA
Tidal Ellipses at MWRA
DETERMINED FROM MWRA CURRENT
Station 1
Station 2
Station 3
Station Lj
Station 5
Station 6
Station 7
Figure
A.3.5 Dissolved Oxygen Deficit (mg/i) For Primary Discharge
At Site 2 Under Stratified Conditions, Average Net Drift
A.3.6 Dissolved Oxygen Deficit (mg/i) For Primary Discharge
At Site 5 Under Stratified Conditions, Average Net Drift
A.3.7 ELA Predicted Sedimentation Rates Site 5, Secondary
Treatment, Stratified Conditions (g/m/day)
A.3.8 ELA Predicted Sedimentation Rates Site 5, Primary
Treatment, Stratified Conditions (g/m/day)
A.3.9 Progressive Vector Plot, Station ZIU, August 1987
A.3.1O Shoreline Impacts, Site L , August 27, 1987
ATTACHMENT A. a - MONTHLY AVERAGED CURRENTS FROM MWRA PROGRAM
Page
A-65
A-66
A-68
A-69
A-72
A-73
A.a.1
Vector
Current
Averages
for
March 1987
A.a.2
Vector
Current
Averages
for
April 1987
A.a.3
Vector
Current
Averages
for
May 1987
A.a. 1
Vector
Current
Averages
for
June 1987
A.a.5
Vector
Current
Averages
for
July 1987
A.a.6
Vector
Current
Averages
for
August 1987
A.b.1
A.b.2
A.b.3
A.b.5
A.b.6
A.b.7
xxi

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LIST OF FIGURES (Continued)
Figure Page
A.b.8 Tidal Ellipses at MWRA Station 9
A.b.9 Tidal Ellipses at MWRA Station 10
ATTACHMENT A. c - NET DRIFTS COMPUTED FROM MWRA CURRENT MEASUREMENTS
A.c.1 Net Drifts Over 10 Tide Cycles at MWRA Station 1
A.c.2 Net Drifts Over 10 Tide Cycles at MWRA Station 2U
A.c.3 Net Drifts Over 10 Tide Cycles at MWRA Station 2L
A.c. 4 Net Drifts Over 10 Tide Cycles at MWRA Station 3U
A.c.5 Net Drifts Over 10 Tide Cycles at MWRA Station 3L
A.c.6 Net Drifts Over 10 Tide Cycles at MWRA Station LW
A.c.7 Net Drifts Over 10 Tide Cycles at MWRA Station 4L
A.c.8 Net Drifts Over 10 Tide Cycles at MWRA Station 51J
A.c.9 Net Drifts Over 10 Tide Cycles at MWRA Station 5L
A.c.1O Net Drifts Over 10 Tide Cycles at MWRA Station 61J
A.c.11 Net Drifts Over 10 Tide Cycles at MWRA Station 6L
A.c.12 Net Drifts Over 10 Tide Cycles at MWRA Station 7U
A.c.13 Net Drifts Over 10 Tide Cycles at MWRA Station 7L
A.c.1U Net Drifts Over 10 Tide Cycles at MWRA Station 9
A.c.15 Net Drifts Over 10 Tide Cycles at MWRA Station 10
ATTACHMENT A.d - LONGITUDINAL STRATIFICATION PROFILES
A.d.1 Cross-Section of Seawater Density Along Northern
Transect, March/April 1987
A.d.2 Cross-Section of Seawater Density Along Northern
Transect, June 1987
A.d.3 Cross-Section of Seawater Density Along Northern
Transect, July 1987
xxii

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LIST OF FIGURES (Continued)
Figure Page
A.d.L Cross-Section of Seawater Density Along Southern
Transect, July 1987
A.d.5 Cross-Section of Seawater Density Along Northern
Transect, August 1987 -
A.d.6 Cross-Section of Seawater Density Along Northern
Transect, September 1987
ATTACHMENT A.e - CALIBRATED TEA TIDAL ELLIPSES COMPARED TO
MEASUREMENTS
A.e.1 Tidal Ellipse from MWRA Measurements (Mar-May 87) and
TEA Calibration (Non-Stratified Conditions)
A.e.2 Tidal Ellipse from MWRA Measurements (Mar—May 87) and
TEA Calibration (Non-Stratified Conditions)
A.e.3 Tidal Ellipse from MWRA Measurements (Mar—May 87) and
TEA Calibration (Non-Stratified Conditions)
A.e.ZI Tidal Ellipse from MWRA Measurements (Aug 87) and TEA
Calibration (Stratified Conditions, Lower Layer)
A.e.5 Tidal Ellipse from MWRA Measurements (Aug 87) and TEA
Calibration (Stratified Conditions, Lower Layer)
ATTACHMENT A.f - SINGLE CONSTITUENT FARFIELD RESULTS
High Tide Concentrations for Base Discharge Loading (0.2 g/sec)
Discharge Site 2:
A.f.1 20 Day Half-Life Constituent, Unstratified, Average
Net Drift
A.f.2 60 Day Half-Life Constituent, Unstratified, Average
Net Drift
A.f.3 Conservative Constituent, Unstratified, Average Net Drift
A.f.1I 20 Day Half-Life Constituent, Unstratified, Worse Case
Net Drift
A.f.5 60 Day Half-Life Constituent, Unstratified, Average
Net Drift
xxiii

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LIST OF FIGURES (Continued)
Figure
A.f.6
A.f.7
A.f.8
A.f.9
A.f. 10
A.f. 11
A.f. 12
Discharge
A.f. 13
A.f. 1J4
A.f. 15
A.f. 16
A.f. 17
A.f. 18
A.f. 19
A.f.20
A.f.21
A.f’.22
Conservative Constituent, Unstratified, Worse Case
Net Drift
20 Day Half-Life Constituent, Stratified, Average
Net Drift
60 Day Half—Life Constituent, Stratified, Average
Net Drift
Conservative Constituent, Stratified, Average Net Drift
20 Day Half—Life Constituent, Stratified, Worse Case
Net Drift
60 Day Half-Life Constituent, Stratified, Worse Case
Net Drift
Conservative Constituent, Stratified, Worse Case
Net Drift
Site 14:
60 Day Half-Life Constituent, Unstratified, Average
Net Drift
60 Day Half-Life Constituent, Unstratified, Average
Net Drift
Conservative Constituent, Unstratified, Average Net Drift
20 Day Half-Life Constituent, Unstratified, Worse Case
Net Drift
Conservative Constituent, Unstratified, Worse Case
Net Drift
20 Day Half-Life Constituent, Stratified, Average
Net Drift
60 Day Half—Life Constituent, Stratified, Average
Net Drift
Conservative Constituent, Stratified, Average Net Drift
20 Day Half-Life Constituent, Stratified, Worse Case
Net Drift
60 Day Half-Life Constituent, Stratified, Worse Case
Net Drift
Page
xxiv

-------
LIST OF FIGURES (Continued)
Figure Page
A.f.23 Conservative Constituent, Stratified, Worse Case
Net Drift
Discharge Site 5:
A.f.2L 20 Day Half-Life Constituent, Unstratified, Average
Net Drift
A.f.25 60 Day Half-Life, Unstratified, Average Net Drift
A.f.26 Conservative Constituent, Unstratified, Average Net Drift
A.f.27 20 Day Half-Life Constituent, Unstratified, Worse Case
Net Drift
A.f.28 60 Day Half-Life Constituent, Unstratified, Worse Case
Net Drift
A.f.29 Conservative Constituent, Unstratified, Worse Case
Net Drift
A.f.30 20 Day Half-Life Constituent, Stratified, Average
Net Drift
A.f.31 60 Day Half-Life Constituent, Stratified, Average
Net Drift
A.f.32 Conservative Constituent, Stratified, Worse Case
Net Drift
A.f.33 20 Day Half-Life Constituent, Stratified, Worse Case
Net Drift
A.f.314 60 Day Half-Life Constituent, Stratified, Worse Case
Net Drift
A.f.35 Conservative Constituent, Stratified, Worse Case
Net Drift
ATTACHMENT A.g - DISSOLVED OXYGEN FARFIELD RESULTS
Farfield Dissolved Oxygen Deficit (mg/l)
A.g.1 Discharge Site 2, Primary Treatment, Stratified,
Worse Case Net Drift
A.g.2 Discharge Site 4, Primary Treatment, Stratified,
Worse Case Net Drift
xxv

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LIST OF FIGURES (Continued)
5, Primary Treatment, Stratified,
Drift
2, Secondary Treatment, Stratified,
Drift
LI, Secondary Treatment, Stratified,
Drift
5, Secondary Treatment, Stratified,
Drift
2, Primary Treatment, Unstratified,
Drift
LI, Primary Treatment, Unstratified,
Drift
5, Primary Treatment, Unstratified,
Drift
2, Secondary Treatment, Unstratified,
Dr i ft
LI, Secondary Treatment, Unstratified,
Drift
A.g.12 Discharge Site 5, Secondary Treatment, Unstratified,
Worse Case Net Drift
Page
Figure
A.g.3
A.g.lI
A.g.5
A.g.6
A.g.7
A.g.8
A.g.9
A.g. 10
A.g. 11
Discharge Site
Worse Case Net
Discharge Site
Worse Case Net
Discharge Site
Worse Case Net
Discharge Site
Worse Case Net
Discharge Site
Worse Case Net
Discharge Site
Worse Case Net
Discharge Site
Worse Case Net
Discharge Site
Worse Case Net
Discharge Site
Worse Case Net
ATTACHMENT A.h - FARFIELD SEDIMENT DEPOSITION RATES
A.h.1 Sedimentation Deposition Rates for Primary Discharge
at Site 2 in Non-Stratified Condition
A.h.2 Sedimentation Deposition Rates for Secondary Discharge
at Site 2 in Non-Stratified Condition
A.h.3 Sedimentation Deposition Rates for Primary Discharge
at Site 2 in Stratified Condition
A.h.LI Sedimentation Deposition Rates for Secondary Discharge
at Site 2 in Stratified Condition
A.h.5 Sedimentation Deposition Rates for Primary Discharge
at Site LI in Non-Stratified Condition
A.h.6 Sedimentation Deposition Rates for Secondary Discharge
at Site 14 in Non-Stratified Condition
xxvi

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LIST OF FIGURES (Continued)
Figure Page
A.h.7 Sedimentation Deposition Rates for Primary Discharge
at Site L in Stratified Condition
A.h.8 Sedimentation Deposition Rates for Secondary Discharge
at Site Il in Stratified Condition
A.h.9 Sedimentation Deposition Rates for Primary Discharge
at Site 5 in Non-Stratified Condition
A.h.1O Sedimentation Deposition Rates for Secondary Discharge
at Site 5 in Non-Stratified Condition
A.h.11 Sedimentation Deposition Rates for Primary Treatment
at Site 5 in Stratified Condition
A.h.12 Sedimentation Deposition Rates for Secondary Treatment
at Site 5 in Stratified Condition
APPENDIX B - MARINE GEOLOGY AND SEDIMENT DEPOSITION
B.i.a Alternative Discharge Site Locations B-2
B.2.a General Station Locations for Sediment Sampling B-li
APPENDIX C - MARINE ECOSYSTEMS
C.i.a Location of MWRA Sampling Locations C-2
C.1.b Bottom Types in the Study Area C-6
C.1.c Principle Features of the Northwest Atlantic C-19
Continental Shelf
C.1.d Massachusetts Bay Phytoplankton Station Locations C-21
C.1.e Integrated Water Column Chlorophyll Concentrations C-23
at Three Stations for Seven Surveys
C.i.f Integrated Euphotic Zone Chlorophyll Concentrations C-2L 1
at Three Stations for Seven Surveys
C.1.g Mean Nutrient Concentrations at Three Stations C-25
for Seven Surveys
C.i.h Integrated Water Column Primary Production Rates C-26
at Three Stations for Seven Surveys
xxvii

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LIST OF FIGURES (Continued)
Figure Page
C.1.i General Movement of Migratory Fish Species in the C-31
Northwestern Atlantic Ocean
C.1.j Locations of Sampling Stations for Determination C- 1 1 1 4
of PCB and PAH Contamination
APPENDIX D - HARBOR RESOURCES
D.2.a Water Transports for Wastewater Treatment Related D-5
Facilities Construction/Operation, 1990-1995
D.3.a Commercial Navigational Resources D-15
D.3.b Typical Commercial and Passenger Ship Routes D .-21
D.3.c Commercial Fishing Resources D-2 4
D.3.d Beaches, Shoreline Parks, and Island Parks D-27
D.3.e Major Boating Public Access Points D-28
D.3.f Sensitive Harbor Resources D-32o
D.3.g Shipwrecks Within 1.5 Miles of Candidate Outfall Sites D-33
D.LLa Projected Peak Boston Harbor Marine Traffic D—37
(1990-1995) Compared to Marine Traffic in 1977
APPENDIX F - SCREENING AND DEVELOPMENT OF ALTERNATIVES
F.1.a Existing Effluent and Sludge Discharge Locations of the F-2
Deer and Nut Island Wastewater Treatment Plants
F.2.a Schematic of Discharge Below a Pycnocline F-7
F.2.b Boundary of Minimum Acceptable Initial Dilution F-9
F.2.c Fate of Effluent Particles During the Flood Portion F-b
of a Tidal Cycle and Beaches, Shoreline, Parks and
Island Parks
F.2.d Fate of Effluent Particles During the Flow Portion F-li
of a Tidal Cycle and Sensitive Harbor Resources
F.2.e Average and Ten Percentile Initial Dilutions at F-13
Sites 2, 14, 5 and 6
xxviii

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LIST OF FIGURES (Continued)
flg e Page
F.2.f Dilutions of Background Buildup Concentrations F-17
With 60-Day Half Lives
F.2.g Cost of Outfall System Alternatives F-19
F.2.h Area of Potentially Acceptable Secondary Effluent F-23
Discharge Locations
F.2.i Alternative Discharge Locations F-25
F.3.a Beaches, Shoreline Parks and Island Parks F- 1 4 4
F.3.b Sensitive Harbor Resources F Lt5
F.Lt.a Profile View of Pipeline Diffuser With One Riser F-5L 1
F.14.b Profile View of Pipeline Diffuser With Eight to F-55
Ten Risers
F. 1 L.c Plan and Profile Views of Tunnelled Diffuser F-57
With Multiple Risers
F.5.a Plan View of Inter-Island Conveyance System Alternatives F-73
F.5.b Profile View of Inter-Island Conveyance System Alternative F_714
APPENDIX H - OPERATIONAL RELIABILITY
H.1.a Schematic of Recommended MWRA Treatment Facilities H-3
H.1.b Recommended MWRA Treatment Facilities H-5
x xi x

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APPENDIX A
PHYSICAL OCEANOGRAPHY AND WATER QUALITY

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A.1 INTRODUCTION
This appendix addresses water quality and sedimentation in Massachusetts Bay as they
are presently and as they will become following discharges of interim primary and
secondary effluent from the Deer Island Wastewater Treatment Plant. Future water
quality and sedimentation conditions are largely dependent on the physical
oceanography characteristics of Massachusetts Bay and these are therefore also
described.
This appendix is divided into two main components:
• A description of existing conditions in the affected environment,
(Section A.2), covering existing water quality conditions as well as the
physical oceanography conditions which will control future water
quality. This description is based on measurements by MWRA and others and
interpretations from various sources.
An assessment of the environmental consequences of the alternatives,
(Section A.3), based on modeling and analyses and including an evaluation
of’ these consequences relative to water quality criteria.
This appendix makes extensive use of the MWRA “Physical Oceanographic
Investigations” contained in Appendix A to Volume V of the Secondary Treatment
Facilities Plan, (MI4RA, STFP V, A, 1987). However, practically all the computer
modeling and analyses were redone, with modifications where Judged appropriate.
Some of the analyses which remained unchanged were redone nonetheless because they
furnished input to other analyses which were redone with different assumptions or
approaches. The physical oceanography data collected by MWRA were also used
extensively, based on magnetic tapes provided by Camp Dresser & McKee.
A-i

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A.2 EXISTING CONDITIONS
A.2. 1 PHYSICAL OCEANOGRAPHY
This section describes the physical oceanography parameters and features of’
importance relative to the fate and impacts of the proposed treated effluent
discharge in Massachusetts Bay. These characteristics can be divided into two major
categories:
• Currents and flow patterns -
• Water column vertical density structure, or stratification
Although the effluent discharge flow rate will be large, its impact on these
parameters will only be local, and existing conditions can be used for the
predictive water quality analyses. The specific parameters of importance are first
discussed, and their role in the processes which control the fate of the effluent
described. The data sources and the information which they can provide relative to
these needs are then reviewed, followed by analyses of the data to provide the
specific information which will be used in the water quality predictions.
A.2.1.1 Processes and Controlling Parameters
Near—Field. Immediately following its discharge through the multiport diffuser, the
effluent will undergo rapid initial dilution with ambient water. The essentially
fresh water effluent will form a buoyant plume rising through the water column
(Figure A.2.1). Both the initial dilution and final height of rise depend on the
current speed, orientation relative to the diffuser and water column
stratification. Since the initial dilution phase is relatively short, on the order
of a few minutes, the important current characteristics are its instantaneous speed
and direction relative to the diffuser. The stratification generally varies on a
longer time scale.
Far—Field. Following initial dilution, the effluent will be carried somewnat
passively by the ambient current, undergoing slower dispersion by ambient
turbulence. In tidal situations, the effluent plume may return over the discharge
A-2

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—_ R_SURFACE ____________
FIGURE A.2.1. SCHEMATIC EFFLUENT PLUME IN THE NEARFIELD
AMBIENT
CURRENT
PLUME
ENTRAINED
AMBIENT
WATER
MAXIMUM HEIGHT
OF I ISE
PORT
BOTTOM
I.
A—3

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area, resulting in the build-up of a background concentration in the discharge
area. The magnitude of this background build-up is dependent on the tidal current
patterns and the non-tidal net drift. Tidal current patterns control the trajectory
and short-term dispersion of the effluent while the net drift controls the rate of
effluent removal from the area. The net drift is the net current over a tide cycle,
as opposed to the tidal current which has zero net speed. The net drift is driven
by a number of’ factors, including large scale weather patterns, freshwater
discharges, local topography and wind and is therefore variable in time and
intensity. As the background build-up develops only slowly, the persistence of net
drifts is important. The background build—up is also dependent on the
stratification which can trap the effluent in the lower layer of the water column
-and, by limiting its vertical and horizontal extent, cause higher concentrations.
In the water quality analyses conducted to evaluate the impact of the discharge,
two-dimensional models were used to calculate background build-ups. Two models were
involved; the first one, TEA, to calculate current speeds and directions at all the
computational nodes and the second one, ELA, to calculate constituent
concentrations. The hydrodynamic model, TEA, performs its computations in the
frequency domain, namely, computes velocities corresponding to different forcing
frequencies (Westerink et al., 1985). The forcing frequencies used for these
analyses are the M2 frequency (1/12.L12 hours) and the “zero” frequency (steady
flow). These two frequencies correspond to the tidal currents and net drifts
discussed above. Field measurements are needed to specify the driving forces
(through boundary conditions) and calibrate the model. The driving forces are the
tidal elevations and water surface slope (tilt) at the open boundary. The model
calibration is based on measured tidal current components and net drifts.
The transport model, ELA, requires the specification of a dispersion coefficient,
which combines the effects of subgrid turbulent diffusion and dispersion due to
vertical averaging (Baptista et al., 198 4). This parameter can be specified based
on the literature, but preferably should be calibrated by comparison with field
measurements. The measurements needed are concentrations of a tracer constituent in
Massachusetts Bay released from a known source.
A_LI

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In the long term, the effluent will disperse over much of Massachusetts Bay and
everatually leave it for the open ocean. These processes are controlled by
large-scale circulation patterns in Massachusetts Bay, including the exchange of
waters between the Bay and the Gulf of Maine.
Shoreline Impacts. Superimposed upon the general flow patterns are local and
generally transient current events which are often driven by winds. Depending on
the location of the discharge in relation to shoreline resources, these events may
occasionally transport the effluent to shoreline in relatively short times.
Sedimentation arid Resuspension. Sedimentation is controlled by the size of the
particles, their concentration in the water column, which affect flocculation; and
the level of ambient turbulence. Resuspension is dependent on the bottom shear
stress, which is a function of the instantaneous water velocity near the bottom. In
coastal situations, high bottom velocities likely to produce resuspension are
generated by waves. For this SEIS, no correlation between waves and resuspension
was attempted. Rather, resuspension was assessed from direct measurements and from
bottom sediment thickness analyses.
Sinvvn ry. This brief review of effluent fate processes pointed to the following
controlling parameters, which are required for direct input into the water quality
analyses and for calibration of elements thereof. Following each item is the
section number where it is discussed in detail, following the general review of
available data.
• Tidal elevations (A.2.1.3)
• Instantaneous currents, magnitude and direction (A.2.1. )
• Tidal current patterns (A.2.1)4)
• Net drift magnitude, direction and persistence (A.2.1. 1 4)
• Sustained shoreward currents (A.2.1. 1 4)
• Stratification profiles (A.2.1.5)
A-5

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A.2.1.2 Data Sources
Massachusetts Bay has been the subject of numerous physical oceanography studies,
each with a rather narrow focus, however. These studies include Bigelow (1927),
Bumpus (19714), Manohar—Maharaj and Beardsley (1973), NOAA (19714), Butman (1977),
EG&G (1976), Mayer (1975), NEA (1975), Fitzgerald (1980), Metropolitan District
Commission (MDC) (1978, 1979, 1982, 19814), Butman (1987) and MWRA (1986, 1987). A
review of these studies relative to the water quality prediction needs of this
project was conducted by MWRA (MWRA STFP, V, A, 1987). Salient features are
summarized below.
The combined Massachusetts and Cape Cod Bays form a body of water enclosed by land
along 75 percent of its perimeter. It is bounded on the north by Cape Ann and on
the south by Cape Cod. It has an area of approximately 3600 square kilometers and
depths of up to 90 m. A characteristic feature is the submarine ridge called
Steliwagen Bank which lies in the middle of the Cape Ann to Provincetown line. The
average depth of Steliwagen Bank is about 30 m with depths as low as 20 m. On
either side, between the bank and the tips of Cape Ann and Cape Cod are deeper
channels.
Currents in Massachusetts Bay, and particularly in the proposed discharge sites
area, are in large part tidally driven. The tides are primarily semi-diurnal, of
the M2 type, with a period of 12.142 hours. Diurnal variations are also observed but
with a much lower amplitude. The tidal range (difference between high and low water
levels) varies during the lunar month (27.3 days), with two spring tides (higher
range) and two neap tides (lower range). The average tidal range is on the order of
2.6 meters along the Gloucester-Provincetown line which separates Massachusetts Bay
from the Gulf of Maine. The tidal range in Boston Harbor is 2.7 meters, with a lag
of approximately 1 minute compared to Provincetown (NOAA, 1987). The volume of
water flowing in and out of the Bay during each tide cycle (tidal prism) is
therefore on the order of 9.5 billion cubic meters, approximately 6 percent of’ the
mean volume of the Bay. In the proposed discharge sites area, the tidal currer:ts
are predominantly east-west with a maximum speed on the order of 10 cm/s. Mucr.
higher velocities occur in some constricted passages such as President Roads anc
Nantasket Roads, with speeds of up to 60 cm/sec.
A—6

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Non-tidal currents in Massachusetts Bay have been the subject of several studies.
Bigelow (1927) first proposed the existence of a cyclonic gyre (counterclockwise
circulation) in Massachusetts Bay, as an extension of the Gulf of Maine eddy. More
recent studies by Butman (1977) indicate a more complicated situation, with the
possible occurrence of two counter-rotating gyres on a transient basis. These gyres
are part of large-scale oceanic circulation tendencies, influenced by the rotation
of the earth through the Coriolis force. The important effects of winds and fresh
water inflows, particularly from the Merrimack River were also noted. And indeec,
progressive vector plots based on the continuous current measurements made by MDC
(198L ) and Butman (1987 - as reported in MWRASTFP, V,A) indicate net drifts of
varying direction and amplitude.
The exchange of water between Massachusetts Bay and the Gulf of Maine controls the
rate at which dissolved constituents discharged through the diffuser are removed
from the Bay. It was noted above that the tidal prism represents approximately 6%
of the volume of the Bay. Some of the water leaving the Bay during ebb, however,
returns during the following flood and the flushing rate is smaller. The flushing
time scale is therefore at least equal to the tidal period divided by 6%, or about
8.5 days. This (exponential) time scale is such that 63% of final steady state
concentration would be reached at that time after the start of a new discharge. This
time scale is therefore a measure of the time needed for the Bay to reach steady
state. Values from 9 days to 2 months were estimated by Butman (1971).
Most of Massachusetts Bay stratifies during the summer months. Starting in June,
surface waters warm-up due to surface heat transfer. In July, a stable
stratification has developed with a thermocline depth on the order of 10 m and a
temperature difference on the order of 10°C. In August, the thermocline deepens to
15 to 25 m, because of wind and convective turbulence in the upper layer, which
cause entrainment of lower layer water. The temperature difference, however,
remains on the order of 10°C. During September, the upper waters start to cool and
the thermocline becomes more diffuse. The fall overturn occurs during November.
These thermal effects are strengthened by the freshwater discharges into the upper
layer, which also decrease surface water density. Large freshwater inflows during
the spring can cause transient stratification periods.
A-i

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Several of’ the physical oceanography data needed for the water quality analyses must
be specific to the proposed discharge sites and specific measurements are therefore
required. MWRA conducted such measurements (MWRA, STFP, V, G, 1987). Several data
needs are also for parameters which are not directly measured but must be extracted
from the measurements. For these, it is important to have the data in a form which
allows easy input into a computer. The MWRA data meet this requirement and,
therefore, form much of the specific basis of the present analyses. The data from
previous studies were used to provide a framework for interpretation of the MWRA
data and complement it where needed.
MWRA Field Data. A preliminary Phase I survey was conducted by MWRA in 1986 to
guide in the selection of’ sites and in the specification of the Phase II program
conducted in 1987.
The Phase I data collection consisted of:
• Drogue tracking of’ short duration (ZL5 to 8.5 hours)
• Vertical density profiling
• Dissolved oxygen profiling and Secchi disk measurements of turbidity
• Surface and sea bed drifter recovery tracking.
The Phase II data gathering was a more detailed study lasting from mid-March to
September 1987 and including the following measurements:
• Tidal elevations at Gloucester, on Cape Ann and Provincetown, on Cape Cod,
to be used to specify farfield model boundary conditions.
• Continuous current speeds and directions at 10 different stations shown in
Figure A.2.2. Some of’ these stations included two current meters,
designated U and L for upper and lower, designed to be above and below the
thermocline in the summer. Details of the current meter coverage are
given in Figure A.2.3. The current meter data were used as direct input
to the riearfield simulations and to calibrate the farfield model.
• Continuous CTDO (conductivity, temperature and dissolved oxygen) at some
of the current meter stations, with the coverage also indicated in
Figure A.2.3. These data were used to characterize ambient water quality
and stratification.
A-8

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MANCHESTER
LEGEND
— SIMULATED DIFFUSER
• SUMMERANDWINTER
• WINTER ONLY
A SUMMER ONLY
12
•
2
10 •
BEVER Y
13
—
‘V _
A3.
11
e
•
A
U
I
2
0
STATUTE MILES
FIGURE A.2.2. LOCATION OF MWRA CURRENT METER STATIONS IN RELATION TO
ALTERNATIVE DiFFUSER SITES.
2
A-9

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1 I
1 I
MAR
APR
MAY
Jup.
CLJRREI .1 DATA
SliDer. I
RL
31.
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5U
5 1.
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9
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CTDIDO DATA
SlaDen 2U
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41.
11DE DATA
ProvInos Icw
G louoss I.r
V flCAL
PROF1UNO
NorVi.rn Tisns.ci
B j8isrn Tr.nMcI
DROGUE
STUDIES
s.Si 2
S
35
4
45
S
SEP
I
(512)
( 5 123)
WI’)
• .
(5126) (TIE)
S
( 8 112)
•
(7129)
ADAPTED FROM MWRA STFP• V.A. 1987
FIGURE A.2.3. COVERAGE OF MWRA 1987 FIELD PROGRAM
A- 10

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• Vertical CTDO profiles along two transects shown in Figure A.2)4, to
characterize ambient stratification.
• Long-term drogue tracking ( days), used to assess net drift.
• Wind speeds, to conduct shoreline impact analyses for extreme events and
identify storms.
• Chemical tracer concentrations, used for the calibration of the farfield
transport model.
All the data gathered during these programs were plotted and analyzed by MWRA (MWRP
STFP V, A and G, 1987). The data were also transferred to magnetic tapes and made
available for the present analyses. These analyses are described in the following
sections. Their objectives are to refine the understanding of local and large scale
processes in Massachusetts Bay and to fulfill the specific data needs of the water
quality analyses.
A.2.1.3 Tides
Water surface elevations along the Gloucester-Provincetown line are needed to drive
the hydrodynarnic model, TEA-NL. Continuous measurements at 10-15 minute intervals
were conducted at Gloucester and Provincetown and referenced to the National
Geodetic Vertical Datum (NGVD). A sample of the data shows the neap-spring
amplitude variations superimposed on the semidiurnal variations (Figure A.2.5). The
data indicate that the amplitudes of the two semi—diurnal tides in one day are not
exactly equal, indicating the presence of diurnal components. A harmonic spectruit
of the Provincetown water surface elevations (Figure A.2.6) shows a distinct peak at
the M2 semi-diurnal frequency (1.93/day), with secondary peak at the diurnal
frequency (1/day). The basis of harmonic analysis is that any periodic function,
h(t), can be decomposed into the sum of cosine components with different
frequencies:
h(t) a(f) cos [ 2, ft —
The harmonic spectrum is a plot of the amplitude, a(f), of the different components
versus their frequency, f. It is equivalent to the Fourier transform of h(t). Each
component also has an individual phase lag, •(f). The amplitudes and phase lags of
the Gloucester and Provincetown tides at the exact M2 frequency are listed in
A-i 1

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STATUTE MILES
T P IORNERN TRANSECTS
S SOUTHERN TRANSECTS
FIGURE A.2.4. LOCATIONS OF MYRA SURVEY TRANSECTS
IIANDIESTER
EWRLY
19
111
113
114
115
17
15
,ThJ u.
a,
S7
56
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55
54
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LEGEND
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A-12

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SOURCE MWRA STFP. VOL. V. APP. A. 19R7
F’JC(JRI A.2.5. WA’FI R. 1,F ,VlI MEAS(JREMFN’I’S AT PROVINCETOWN (TOP)
(;t,4) J(:Es’I’Ii{ ( 1II)I) 1) ,-\NIP ‘IIII II 1)1 I I ER I NCP (? OT’I’OM)

-------
1.5
— M2 TIDE
1.2
0.9-
uJ
-J
< 0.6
SEMI-DIURNAL TIDE
JCOMPONENTS
0.3 DIURNAL TIDE /
COMPONENTS
- -. --—--—- - ... -- —. - - - . — .-
0. 4. 6. 8. 10
FREQUENCY 1/DAY
FIGURE A.2.ô. HARMONIC ANALYSIS OF PROVINCETOWN TIDAL ELE\AT1O
A-1)4

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Table A.2.1. These values were obtained using a data record with a length of two
lunar months, to eliminate the lunar phase effects on tidal amplitudes. It can be
hypothesized that net drifts in Massachusetts Bay are due to differences in mean
water levels (i.e. exclusive of tidal variations) between Gloucester and
Provincetown. This water level difference is referred to as the boundary “tilt”.
An analysis of the tilt performed by MWRA and the results are shown on
Figure A.2.7. The water surface elevation records at Provincetown and Gloucester
show fluctuations with a time scale on the order of 7 to 10 days, which is the
period of sub-tropical storms. The difference in filtered water levels, or tilt,
however, varies with a much slower time scale, on the order of several months. In
general, the tilt varies between +10 cm and —10 cm, with extremes on the order of
15 cm.
TABLE A .2.1 - AMPLITUDE AND LAGS OF M2 COMPONENTS
OF WATER LEVEL MEASUREMENTS
Gloucester
Provincetown
Amplitude
(m)
1.258
1.311
Phase lag
(min) 1
10.6
0.0
1. A smaller lag indicates that the tide wave arrives earlier.
A.2.1. 1 4 Currents
Extensive current measurements in Massachusetts Bay were conducted by MDC (1979,
19814), Butman (1987) and MWRA (1987). The latter were analyzed and displayed in a
great variety of ways (MWRA STFP VG, 1987): time histories (magnitude-direction and
east-north components), scatter plots (magnitude—direction and east—north
components), progressive vector plots, stick plots, spectral density plots and
frequency distribution plots. As discussed earlier, important features of the
current relative to water quality analyses are i) instantaneous values, ii) tidal
components and iii) net drifts.
Instantaneous Currents. These are actual instantaneous currents, irrespective of
their origin. They can be gauged to varying degrees from most of the data
A- 15

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p.
I
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I
———-
-
—
22
24
24
, It
-Is
if 24
-I I
f ‘4
1_I It
21 1
.,.,% I,
SOURCE: MWRA STFP. VOL V APP A. 19R7
FR;IIRE A.2.7. HLTF RED WATER. LEVELS ATPROVINCETOW (TOP)
(;L()I (;ESTER (MWI)Ii ) ANtI ThEIR. DIFFERENCE (BOTTOM)
12
4.
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presentation formats mentioned above. Instantaneous currents are important for the
initial dilution calculations and, for those, cumulative exceedance frequencies will
allow a statistical analysis of the mixing zone concentrations. These data are
sunnnarized in Table A.2.2. A slight increase of current velocities is apparent as
one goes from Station 2 to 11 to 5, which are close to diffuser Sites 2, LI and 5.
Note that lower meter velocities are often higher than those at the corresponding
upper current meters.
Instantaneous directions, which also affect initial dilution, are best gauged
through the magnitude-direction scatter plots, which are reproduced in Figures A.2.8
to A.2.1O for Stations 2, 11 and 5 for the month of August, 1987. Results are also
available for other time periods, with similar trends (MWRA, STFP V, C, 1987). The
August results are shown here because this period of the year leads to the lowest
nearfield dilutions. The plots clearly show a bimodality of current directions due
to the tidal effects (primarily east-west). This factor is important for the
orientation of the diffuser, as increased nearfield dilutions can be obtained when
the diffuser is oriented perpendicular to the dominant current direction.
Tidal Currents. Harmonic analysis of the MWRA continuous current measurements shows
the predominant effects of tides, (Figure A.2.11). In order to further analyze the
tidal component of’ currents in Massachusetts Bay, tidal ellipse plots were prepared,
based on the harmonic analysis. For each measurement station, the amplitude and
phase lag of the Fourier component at the M2 frequency of the u and v current
components was calculated. As customary, the u component is in the east-west
direction, positive towards the east, and the v component is in the north-south
direction, positive towards the north. Based on these Fourier amplitudes and lags,
tidal ellipses can be constructed as the locus of the end of the velocity vector at
one point during one tide cycle. The harmonic analysis requires continuous data
and, therefore, small data gaps (less than about LI hours) in the records were filled
by interpolation. Tidal ellipses are presented in Attachment A.b, based on the MI4Si.
data for the months of March to May 1987 and August 1987. These plots show that the
amplitude of the tidal currents in the upper waters is approximately the same at
Stations 2 and LI, (15 cm/sec) and slightly lower at Station 5, (12 cm/see). The
cumulative exceedance frequency plots (MWRA, STFP V, C, 1987), show that these
values are exceeded 2O of the time at Station 2, 25% of the time at Station 14 and
h-17

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Meter
Station
1
2U
2L
3U
3L
4U
IlL
5U
5L
6U
6L
7U
7L
9
10
Maximum
23.3
33.3
31.6
56.3
l 7 .6
31.6
38.7
35.0
145.5
140 .0
30.8
140.7
83.5
105.0
101.0
METER MEASUREMENTS
Speeds (cm/s)
101 (a) 50 %(a) 90 %(a )
1.9 6.2 11.9
3.6 10.2 18.5
3.0 9.5 15.8
14.2 11.5 20.1
11.14 11.6 22.0
3.6 9.6 18.5
11.14 12.8 23.2
5.1 11.5 19.7
14•14 11.9 21.3
3.14 9.2 17.5
2.3 7.1 13.6
11.5 11.0 20.5
3.1 10.0 21.0
2.11 21.0 50.9
5.2 28.6 52.5
1987 MWRA CURRENT
TABLE A.2.2 - STATISTICS OF
Vector Mean
Speed Direction
________ ( cm/s) (degrees true )
1.12 240
2.05 209
2.65 160
1.68 180
2.05 256
1.07 99
3.914 336
1.39 252
1.48 29
2.90 260
1.50 300
3.13 131
1.73 50
5.146 311
1.15 303
Source: MWRA STFP, Vol. V, App. A, 1987
(a) These numbers represent the percent
indicated value: e.g. for Station 1
of the time; below 6.2 cm/s for 50%
the time.
of time the current speed is below the
current speeds are below 1.9 cm/s for 10%
of the time; and below 11.9 cm/s for 90% of
A- 18

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•LI(CTI ’ D I
FIGURE A.2.8. MAGNITUDE-DIRECTION SCATTER PLOT FOR
STATiON 2, AUGUST 1987
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FIGURE A.2.9. MAGNITUDE-DIRECTION SCATTER PLOT FOR
STATION 4, AUGUST 1987
A-20
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SOURCE: MWRA STFP . VOL V. APP G, 1987
FIGURE A.2.1O. MAGNITUDE-DIRECTION SCATTER PLOT FOR
STATION 5, AUGUST 1987
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FREQUENCY
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0. 5. 10. 15. 20. 25.
FRED (/DAY)
FIGURE A.2.11. HARMONIC ANALYSIS OF CURRENTS AT STATION
AUGUST 1987 (EAST-WEST COMPONENT)
p -22

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1 5% of the time at Station 5. This indicates that, in the upper waters, the
relative influence of tides on currents decreases as one moves offshore. At the
lower current meters, the tidal current amplitudes are again approximately equal at
Stations 2 and 1 (12 cm/see), but slightly higher at Station 5 (15 cm/see). These
tidal current magnitudes are exceeded 30% of’ the time at Station 2, 50% of the time
at Station i4 and 35% of the time at Station 5, showing no clear trend of the
relative tidal influence with distance offshore.
The tidal ellipse plots were used for the calibration of the two-dimensional
hydrodynamic mathematical model of Massachusetts Bay, TEA (A.3.6).
Net Drifts. Progressive vector plots based on current measurements show that net
drifts are highly variable in time, with periods of practically no net drift and
periods of sustained high net drift (MDC l 9 8J 4 ; Butman 1987; MWRA 1987). Spacially,
net drifts are also very variable, as can be seen on maps of monthly averaged
current speeds shown in Appendix A.a. While the monthly averaging period is quite
arbitrary, it is long enough to erase the tidal effects. The results indicate that
there is no coherence between monthly net drifts at the different current meter
locations, and the upper and lower current meters often give significantly different
net drifts. This display of the data does not support the gyre model discussed
earlier and would tend to indicate that net drifts are largely due to localized wind
events and perhaps to density effects resulting from freshwater inflows.
In order to gain additional perspective on net drifts and their persistence, net
drifts over a fixed number of complete M2 tidal cycles were computed and plotted
versus time. Experimentation showed that using a 10-tide cycle period for the
calculations sufficiently smoothed short—term fluctuations yet provided a usable
measure of net drift persistence. On these plots, which are presented in Appendix
A.c, velocities and directions at any time therefore represent the magnitude and
direction of the net drift during the following 10 tide cycles, approximately
5 days. These plots, in effect, show running averages of the measured currents.
These plots clearly show a periodicity of high net drifts with a period on the order
of 7 to 10 days. The stronger net drift events are usually apparent at several
measurement stations. For example, the high net drift period of April 1-6 can be
seen at Stations 3, 5 and 7. However, the April 11-19 high net drift period at
A-23

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Stations 5 and 7 is weak at Station 3. This indicates that the high net drifts may
be of limited areal extent. The net drifts during these two periods were c
opposite direction, the first one towards the south and the second one towards the
north. Further examination of’ the net drift plots indicates that this feature is
generalized, with net drifts being in either direction at most sites.
During the stratified summer months, the net drifts are often significantly
different at the upper and lower current meters. In general, the upper meters gave
larger net drifts, except at Station L I, where the lower net drifts are larger. The
directions of the upper and lower net drifts are also often different, without any
perceivable trend.
A.2.1.5 Stratification
As discussed earlier, Massachusetts Bay stratifies in the summer due to surface
heating. The MWRA field program included measurements of temperature and salinity,
from which density is determined, along two transects at several times during the
spring and summer of’ 1987. The resulting vertical density contours are provided in
Attachment A.d. These show a thermocline during the summer months at a depth of 10
to 15m, with large variations during the tidal cycle. Vertical density profiles
based on these measurements were used for the initial dilution analyses.
The continuous density records produced by MWRA clearly show the tidal variations,
particularly in the bottom to top meter density differences, which are a measure of
the stratification. During the summer, this difference exhibits semi-diurnal
variations of up to 1 sigma-t unit (0.001 g/ccm). The average top to bottom density
difference varies during the summer due to the surface heating/cooling cycles and
wind mixing, but never vanishes. This indicates that effectively distinct top and
bottom layers exist, with significantly reduced interchange. Relative to water
quality analyses, this suggests that models recognizing the existence of these
layers are desirable. This was accomplished in this SEIS by simulating the lower
layer independently during the stratified season (A.3.6).
A _2 L 1

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During the spring, the continuous density measurements indicate that strong
stratification can develop following major runoff events. This stratification,
however, is not uniform and is of relatively short duration so that prolonged
blockage of the effluent plume in a lower layer would not be expected.
A.2.2 WATER QUALITY
A.2.2.1 Constituents and Criteria
Water quality is measured by the concentrations of dissolved and suspended
constituents in the water column, as well as other more subjective measures such as
.aesthetics or odor. The list of constituents and factors to be considered can be
established based on applicable water quality standards and criteria. Those are:
• The Massachusetts Surface Water Quality Standards
• The U.S. EPA Water Marine Quality Criteria for
• Aquatic Life
• Human Health
These standards and criteria are reviewed below, with the objective of determining
the constituents which should be considered as measures of water quality, to
characterize present conditions and impacts due to the discharge alternatives.
The Massachusetts Surface Water Quality Standards are defined in the Code of
Massachusetts Regulations, T .tle 31L4. They involve minimum criteria applicable to
all waters, listed in Table A.2.3, and additional criteria for specific classes of
waters, defined on the basis of’ their use. The waters of the Outer Boston Harbor
are classified as SA, consistent with the following uses: protection and
propagation of fish, other aquatic life and wildlife; primary and secondary contact
recreation such as swimming and boating; and shellfish harvesting without depuratior
in approved areas. The additional criteria pertaining to SA class waters are listed
in Table A.2.LL.
A-25

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TABLE A .2.3 COMMONWEALTH OF MASSACHUSETTS SURFACE WATER
QUALITY STANDARDS’ - MINIMUM CRITERIA
APPLICABLE TO ALL WATERS
Parameter Criteria
1. Aesthetics All waters shall be free from pollutants in
concentrations or combinations that:
a) Settle to form objectionable deposits;
b) Float as debris, scum, or other matter to form
nuisances;
c) Produce objectionable odor, color, taste, or
turbidity; or
d) Result in the dominance of nuisance species
2. Radioactive Shall not exceed the recommended limits of the United
Substances States Environmental Protection Agency’s National
Drinking Water Regulations.
3. Tainting Shall not be in concentrations or combinations that
Substances produce undesirable flavors in the edible portions of
aquatic organisms.
i4 Color, Turbidity, Shall not be in concentrations or combinations
Total Suspended that produce undesirable flavors in the edible
Solids portions of aquatic organisms.
5. Oil and Grease The water surface shall be free from floating oils,
grease and petrochemicals, and any concentrations or
combinations in the water column or sediments that are
aesthetically objectional, objectionable or deleterious
to the biota are prohibited. For oil and grease of
petroleum origin the maximum allowable discharge
concentration is 15 mg/i.
6. Nutrients Shall not exceed the site-specific lin its necessary to
control accelerated or cultural eutrophication.
7. Other Waters shall be free from pollutants alone or in
Constituents combinations that:
a) Exceed the recommended limits on the most sensitive
receiving water use;
b) Injure, are toxic to, or produce adverse
physiological or behavioral responses in humans or
aquatic life; or
c) Exceed site-specific safe exposure levels determined
by bioassay using sensitive resident species.
‘310 CMR Z .O3.
A-26

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TABLE A .2.11 COMMONWEALTH OF MASSACHUSETTS SURFACE WATER
QUALITY STANDARDS’ - ADDITIONAL CRITERIA FOR
MARINE CLASS SA WATERS
Parameter Criteria
1. Dissolved Oxygen Shall be a minimum of 85% of saturation at water
temperatures above 77°F (25°C) and shall be a minimum of
6.0 mg/i at water temperatures of 77°F and below.
2. Temperature None except where the increase will not exceed the
recommended limits on the most sensitive water use.
3. pH Shall be in the range of 6.5-8.5 standard units and not
more than 0.2 units outside of the naturally occurring
range.
1 L Total Coliform Shall not exceed a median value of 70 MPN per 100 ml
Bacteria and not more than 10% of the samples shall exceed
230 MPN per 100 ml in any monthly sampling period.
‘310 CMR 14.03
A-27

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Many of the minimum criteria are based on avoidance of objectionable effects and are
therefore qualitative. Quantitative criteria corresponding to these effects, such
as aquatic toxicity, are provided by the EPA criteria discussed below. Quantitative
criteria are provided for SA Class waters for dissolved oxygen, pH, and coliforin
bacteria. The effluent discharge is required by law to meet the Massachusetts Water
Quality Standards at the edge of the mixing zone.
The EPA Water Quality Criteria are provided in the so-called “Gold Book” (USEP
1986). These criteria include aquatic life and human health criteria, the latter
including toxicity, carcinogenicity and taste and odor criteria.
-Aquatic life criteria are further discussed in the “Technical Support Document for
Water Quality-Based Toxics Control” (USEPA, 1985). Two approaches can be used to
assess and control toxicity to organisms. The chemical specific approach is used
here. The whole effluent approach will be applied when the necesary data becomes
available.
The chemical specific approach is based on published bioassay laboratory test
results involving each chemical independently. This approach has the advantage of
requiring no effluent bioassay test but it assumes that the composition of the
effluent is known (so that the concentrations of chemicals can be determined), that
the toxicity of separate toxicants is not additive, and that those toxicants are
bioavailable in the effluent.
For chemical specific tests, acute and chronic concentrations are determined. The
acute (short term) concentration, called the Criterion Maximum Concentration, or
CMC, is the concentration which must not be exceeded at a specified point with a
frequency of more than 1 hour every 3 years. However, it is recognized that this is
unenforceable and, therefore, the frequency of occurrence, for enforcement purposes,
is increased to 1 day every 3 years. The chronic (long term) concentration, called
the Criterion Continuous Concentration or CCC, is the concentration which must not
be exceeded with a frequency of more than LI consecutive days in 3 years. CMC’s and
CCC’s are provided for a range of chemicals in the “Gold Book”. These values are
provided in Table A.2.5 for the chemicals of concern. These are the same as were
considered by MWRA in their analyses. The process by which this list of chemicals
A-28

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was established included the following steps, starting from the list of chemicals
detected in the influent to the plant:
1. Remove those chemicals for which no water quality criterion exists
2. Remove those constituents that already meet the criteria in the influent
3. Remove those chemicals detected in the influent infrequently
Lf• Add chemicals for which the detection limit is greater than the criteria
Human health criteria include human toxicity criteria, carcinogenicity criteria and
taste and odor criteria. The carcinogenicity criteria are based on risk factors of
1 icr 5 , i x 1O or 1 x 10 chances of contracting cancer or suffering genetic
mutation in a lifetime given assumed intakes of contaminated fish. The Division of
Water Pollution Control of the Massachusetts Department of Environmental Quality
Engineering (DEQE) typically utilize a risk factor of iO or lower, which they
believe allows for acceptable protection of the public’s health and is attainable
and enforceable. For this project, the Division recommended that the MWRA utilize
the io_6 risk factor but that it may consider use of a risk factor of 1O in
certain situations. Those situations must be reviewed with t ’he Division prior to
utilization (May 15, 1987 letter of T.C. MacMahon to M. Gritzuk). Criteria
concentrations corresponding to both risk factors are listed in Table A.2.5.
Additional discussion of the water quality criteria, focused on their interpretation
relative to the water quality analyses, is provided in Section A.3.1.
A.2.2.2 Dissolved Oxygen
Numerous and extensive dissolved oxygen (DO) measurements have been conducted in
Boston Harbor and Massachusetts Bay. Review of those prior to 19814 indicated that
in Boston Harbor, and. even in the vicinity of the existing discharges, DO levels
rarely go below 6 mg/i (MDC, 198L ). The data from 1978 and 1979 MDC individual
surveys at multiple depths indicated that in the vicinity of the Deer Island
Discharge 90 percent of the measurements exceeded 7 mg/l and the lowest DO recorded
was 6.2 mg/l. In the vicinity of the Nut Island discharge 80 percent of the
measurements exceeded 7 mg/I and the lowest DO recorded was 5.9 mg/i. Of the 1 4OO
A-29

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TABLE A.2.5 SALTWATER AQUATIC LIFE AND HUMAN HEALTH
WATER QUALITY CRITERIA
Carcinogenicity
Chemical CMC CCC Toxicity io 10-6
Taste
and Odor
VOLATI LES
benzene 5,100
bromomethane 12,000
chloroform --
ethylbenzene 1430
methyl chloride 12,000
styrene 1430
tetrachloroethylene 10,200
ACID, BASE NEUTRALS
700
6,1400
-- 3,280
6,1400 --
-- 3,280
45O --
3.14
3.14
-- 3.090
3.14 --
129
36
9.3
50
1400.
157.
157.
157
88.5
3.11
0.311
0.311
0.311
0.311
0.311
500,000.
0.311
0.311
0.2
0.311
0.00714
0.311
0.311
0.311
0. 175
1.17
anthracene
benz(a)anthracene
benz ( b) fluoranthene
benz ( k) fluoran thene
benz(g,h, i)fluoranthene
benz(a)pyrene
bis(2—ethylhexyl)phthalate
butylberizyl phthalate
chrysene
dibenz(ah ,h)anthracene
3, 3—dichlorobenzidine
2, 1 4-dichlorophenol
di-n—octyl phthalate
fluorene
hexachlorobenzene
indeno( 1 ,2,3—cd)pyrene
naphthalene
phenanthrene
py rene
METALS
arsenic
beryllium
cadmium
chromium
copper
110.
15.7
15.7
15.7
8.85
0.311
0. 0311
0. 0311
0.0311
0.0311
0. 0311
50,000.
0.0311
0. 0311
0.02
0. 03 11
0. 000714
0. 0311
0.0311
0. 0311
0.0175
0.117
300
300
300
300
300
300
2,91414
2,91414
300
300
2,91414
300
160
300
2,350
300
300
60
143
1, 100
2.9
0.3
1,000
A-30

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TABLE A.2.5 SALTWATER AQUATIC LIFE AND HUMAN HEALTH
WATER QUALITY CRITERIA (Continued)
Chemical
CMC
CCC
Toxicity
Carcinogenicity
Taste
and Odor
i0 5 io 6
METALS (continued)
lead
mercury
nickel
selenium
silver
zinc
1110
2.1
75
760
2.3
170
5.6
0.025
8.3
—-
—-
58
——
0.1146
—-
——
——
—- -
—- --
—— --
—— --
—— --
—— — —
—— --
--

--
--
——
5,000
PESTICIDES
aidrin
chiordane
dieldrin
heptachior
toxaphene
1.3
0.18
0.111
0.053
0.21
--
0.0014
0.0019
0.0036
0.0002
—-
--
—-
--
--
0.00079 0.000079
0.00 148 0.000148
0.00076 0.000076
0.0029 0.00029
—- --
--

--
--
OTHER CHEMICALS
--
0.03
--
0.00079 0.000079
--
PCBs
Source:
1986, and updated in
1986 and
From the EPA Gold Book as published in May,
again in May, 1987; all units are ig/l.
A-3 1

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measurements obtained at stations surrounding the discharges, only one was less thar,’
6 mg/i.
Extensive discrete DO measurements were also gathered by MDC in the Site 5 area in
July and August, 1978 and 1979. Summer represents worse conditions relative to DO
since the saturation DO concentration is lower and bottom waters are isolated from
the water surface by the thermocline. Indeed, strong vertical variations of DO were
observed, with supersaturation in the top waters and below saturation concentrations
in the bottom waters. The supersaturation indicates photosynthetic activity. Out
of all the measurements, approximately 83 percent exceeded 7 mg/i and 1 percent were
below 6 mg/i. The average DO in the bottom 10 meters was 7.6 mg/i. It was noted
that DO levels could vary by as much as 2 mg/i during a 12-hour period, possioiy
because of diurnal changes in photosynthetic activity.
The MWRA field program included continuous measurements of dissolved oxygen at three
stations and three depths. Because these measurements were continuous, they had the
potential for detecting unusual events which may have been missed by the earlier
shorter term surveys. Such an event was recorded on June 6, 1987, where DO levels
dropped to 5 mg/i at Station 3 Upper (Figure A.2.12). Unfortunately, meters at
other nearby stations were not operative at this time and the validity of’ these
measurements cannot be corroborated. The wind and current records indicate nothing
unusual on that date, and, therefore, the origin of these measurements remains
unclear. Other than this event, the MWRA spring and summer data tend to confirm the
earlier summer time surveys, with high dissolved oxygen values in the upper waters,
up to 12.5 mg/i, and somewhat lower values in the bottom waters. Out of the LI,056
DO measurements at lower meters during June-August 1987, the lowest value was 7.8
mg/i and only 1 measurements were below 8 mg/i.
Water quality data collected in September, 1986, however, indicated DO
concentrations in the lower layer ranging from 5.9 mg to 6.8 mg/i. Similarly, in
October 1987, MWRA measurements indicated low dissolved oxygen values for a perioo
of about two weeks at the lower meters. At Station Z , the lower meter DO
concentrations showed high semi-diurnal fluctuations (on the order of 3 mg/i) with
an average of approximately 6.5 mg/i (Koib, personal coinmuncation). The lower meter
depth was 17m (MLW) and the water depth was 2Orn. The large semi-diurnal fluctuation
A-32

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F’I(;I’RF A.2.12. WATER. QUALITY MEASIJREMENTS AT STATION 311 DI!RIN( SlIMMER
1987 (S1IOW lOW J)ISSOI,VLV) OXYCEN RECOR IWI) ON I ‘\I 6, 1987)
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indicates that the meter was alternatively in the upper layer and in the lower layer
during tidal variations. This is confirmed by strong temperature variations at the
same frequency. Vertical density profiles are not available to locate the
pyonocline, but the foregoing observations indicate that it was at a depth
comparable to that of the lower meter, i.e. 17m. The lower layer depth would then
become very small (3m or less) and it is possible that the low DO concentrations
recorded would be due to resuspension oxygen demand caused by breaking internal
waves at the pycnocline. This aspect is important because it affects the selection
of ambient DO concentrations for the impact analyses (A.3.8.1).
A.2.2.3 pH
The pH is a measure of the acidity or alkalinity of water and it is determined from
the concentration of hydrogen ions in the water. A pH of 7.0 corresponds to neutral
conditions; acidic conditions have a pH below 7.0 and basic conditions of pH above
7.0. In the ocean, pH is controlled primarily by carbonate and bicarbonate (bases)
and carbonic acid.
Measurements of pH conducted by MDC in summer 1979 in the Site 5 area ranged from
7.9 to 8.1, with an average of’ 8.0. Harbor values were similar but with greater
variablity, especially due to freshwater inputs. The pH was sometimes noticeably
lower in the inner harbor and nearshore areas than in the outer harbor, but on other
days, there was little variation among stations (MDC, 198Lt).
As part of their field program, MWRA conducted pH measurements in April 1987 in
Broad Sound. The measured pH values ranged from 8.1 at the surface to 7.9 at a
depth of 30m (MWRA, STFP V,A 1987). These measurements, therefore, confirm the
earlier data.
A.2.2.i1 Suspended Solids
Extensive measurements of’ suspended solids were conducted during the MDC 301-h
waiver applications process in Boston Harbor and in the general area of the proposed
discharge sites (MDC, 19814). In the harbor, great variability was encountered in
particular in response to runoff events. In the proposed discharge sites area,
A - 3i4

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total suspended solids ranged from 1 mg/i to 12 mg/i, with an average concentration
of 14.5 mg/i. These measurements were conducted in the summer.
Suspended solids concentrations were also measured during the MWRA field program, at
two stations shown in Figure A.2.13. These measurements, which were made in
April 1987 gave total suspended solids concentration on the order of 2.5 mg/i at
Station B2, which is between Sites 2 and 14, and 1.5 mg/i at Station Hi, located at
the edge of Steliwagen Bank, (MWRA STFP, VM, 1987). These values are much lower
than those of MDC, probably because of lower primary productivity in the spring.
A.2.2.5 Toxic Chemicals
Much of the existing data on toxic chemical concentrations in Massachusetts Bay were
collected in Boston Harbor, which is largely Influenced by the present discharges
from Deer Island and Nut Island Treatment Plants and the CSOs.
Concentrations of dissolved and particulate metals in the water column have been
measured at two stations in Massachusetts Bay (Figure A.2.13), as part of the MWRA
field program (MWRA, STFP V, B, 1957) and are summarized in Table A.2.6. These
concentrations are generally low, and well below the CCC values, except for copper
(average concentration of 0.14 big/i) which is on the same order of magnitude as the
CMC (2.9 ig/l).
Concentrations of dissolved and particulate PCBs were measured at the same stations
for samples collected in April, 1987 (Battelle, 1987). These measurements indicate
that both dissolved and particulate PCB concentrations (calculated as Aroclor i25! )
are low, with a maximum value of 0.0073 ug/l for dissolved PCB (Table A.2.7). These
concentrations, however, are higher than the i0 and 1o 6 carcinogenicity criteria.
A—35

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BC RLY
STATUTE MILES
tI( U1th A. .1i. LOCATIONS OF THE SUSPENDED SOUDS, METALS, AND PCB SAMPLING
STATiON S
I
HI 1
S2
OOSTO
‘p
V __
I
QUINCY
3ArnT
1AL ’R
A—36

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TABLE A.2.6
METAL CONCENTRATION IN WATER COLUMN AT TWO STATIONS
IN MASSACHUSETTS BAY
Depth
Station (m) Phase
As,
.ig/1
Cd,
i g/1
Cr,
ugh
Cu,
ugh
Hg,(1) Ni, Pb,
ng/1 ig/1 ugh
V, Zn,
ug/]. ugh
Hi 11.8 Diss.
Part.
Tot.
0.1 12
0.0114
0.113
0.023
0.001
0.0214
0.26
0.055
0.31
0.37
0.039
0.111
1.97
1.63
3.61
0.22 0.0145
0.127 0.050
0.35 0.096
1.11 0.614
<0.0145 0.086
1.11 0.73
22.2 Diss.
Part.
Tot.
0.50
0.013
0.51
0.025
0.001
0.026
0.26
0.056
0.32
0.30
0.027
0.33
2.07
0.97
3.11
0.57 0.056
0.376 0.0143
0.95 0.099
1.30 0.72
<0.0115 0.072
1.30 0.79
148.7 Diss.
Part.
- Tot.
0.53
0.012
0.55
0.026
0.001
0.027
0.27
0.051
0.32
0.36-
0.026
0.38
2.01
2.10
11.11
0.38 0.0148
0.081 0.032
0.147 0.078
1.33 0.85
(0.0113 0.069
1.33 0.92
B2 8.6 Diss.
Part.
Tot.
0.014
0.010
0.141
0.030
0.002
0.032
0.19
0.075
0.26
0.116
0.060
0.52
1.614
0.50
2.13
0.53 0.069
0.153 0.058
0.68 0.128
1.25 1.16
<0.01414 0.262
1.25 1.60
19. 4 Diss.
Part.
Tot.
0.50
0.013
0.51
0.027
0.001
0.028
0.19
0.093
0.29
0.36
0.035
0.39
1.3
0.148
1.8
0.115 0.031
0.051 0.067
0.50 0.098
1.25 0.91
0.032 0.156
1.27 1.06
214.11 Diss.
Part.
Tot.
0.119
0.022
0.051
0.51
0.025
0.001
0.026
0.25
0.167
0.142
0.116
0.063
0.145
2.12
1.53
3.65
0.65 0.106
0.5014 0.083
1.1 0.189
1.39 1.02
0.055 0.1514
1.1414 1.17
CCC Concentration
36
143
1100
25
7.1 5.6
58
CMC Concentration
69
9.3
50
2.9
2100
1110 1140
170
B, 1987
Source: MWRA, STFP V,
(1) Note different unit
A-37

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TABLE A.2.7 CONCENTRATIONS OF PCB IN SEAWATER COLLECTED AT
TWO STATIONS IN MASSACHUSETTS BAY IN APRIL, 1987
Depth
Station (m)
PCB
Concentrations
( g/l)(
Dissolved
Particulate
B2 11 0.0005 <0.0005
B2 11 0.0020 0.0006
B2 11 O.OOlZi 0.0005
B2 20 <0.0005
B2 20 0.0022 <0.0005
B2 20 <0.0025 <0.0005
Hi iZi 0.0073 <0.0005
Hi 114 <0.0005
Hi 40 0.0062 <0.0005
Hi 14Q 0.0033 0.0005
Field Blank 0.00075
Field Blank 0.0015
Laboratory Process
Blank 0.0018
Criteria
Aquatic Life CMC NA
Aquatic Life CCC 0.030
10_S Carcinogenicity 0.00079
10—6 carcinogenicity 0.000079
(1) Calculated as Aroclor 12514.
Adapted from Battelle, 1987.
A-38

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A.3 WATER QUALITY CONSEQUENCES OF ALTERNATIVES
A.3.1 CONSTITUENTS
The water quality impact analyses are to furnish the basis for i) water quality
criteria compliance evaluations and ii) water column and benthic ecosystem impact
assessment.
For these, the parameters and constituents which must be evaluated are:
• Dissolved Oxygen (DO) as affected by the biochemical oxygen demand of the
effluent, both carbonaceous (CBOD) and nitrogenous (NBOD);
• Suspended Solids and Sedimentation , resulting from the discharge of’ solids
with the effluent;
• affected primarily by the alkalinity of’ the effluent;
• Nutrients , including nitrogen, phosphorus and silica, which support primary
productivity and the development of objectionable algal blooms;
• Toxic Chemicals , including volatile organic compounds (VOC’s), acid/base
neutrals, metals, pesticides and other chemicals. A list of toxic
chemicals to be considered has been developed by 14WRA based on measurements
of influent quality, the applicable water quality standards and criteria
and specific toxicity concerns (MWRA, STFP V, A, 1987).
The measurements of water quality relative to these parameters are water column
concentrations and sediment deposition rates. These are the result of a balance
between loadings and removal or fate processes. These processes include transport
processes, which are the same for all the constituents, and physico-bio—chemical
processes which are constituent specific. These elements are covered below.
A.3.2 LOADINGS
The discharge rates or loadings of the constituents identified above are provided in
Table A.3.1 for primary and secondary treatment effluent. These loads are based or.
the MWRA (STFP V, A and III, 1987).
A-39

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TABLE A.3.1 CONSTITUENTS LOADINGS
silver
zinc
aidrin
L4.14’...DDT
dieldrin
heptachlor
polychiorinated biphenyls (PCBs)
(1) Average day, year 1999 for primary, 2020
(2) Reduced removal efficiency during storms.
(3) Other nutrients are not limiting.
Source: KWRA STFP III and V, A 1987.
Constituents
Primary Effluent
Secondary Effluent
High Low
Low
Conventional
Ground-
Ground-
Ground- Ground-
Pollutants (g/sec)
water
water
water water
Carbonaceous BOD
2,915
3.1145
3714 858
Nitrogenous BOD
1,785
1,785
1,785 1,785
DO Deficit
139
278
139 278
Total Su çnded Solids
Nitrogen’”
1,150
390
390
363
390 390
Flows 1 ( gd)
(mi/s)
377
16.5
657
28.8
390 670
17.1 29.3
Toxic Chemicals (mg/see)
Primary
Effluent
Secondary Effluent
Mean Standard High 2
Deviation
Mean
Standard
Deviation
benzene
86.8
16.0
14.3 0.8 26.0
brornomethane
327.6
116.8
16.14 5.8 81.9
chloroform
117.1
514.0
11.7 5.14 58.5
ethylbenzene
175.8
79.14
8.8 14.0 52.7
methylene chloride
632.3
14514.6
31.6 22.7 279.14
styrene
197.2
147.7
19.7 14.8 59.2
tetrachloroethylene
3214.2
189.9
32.14 19.0 97.3
trichloroethylene
183.3
97.14
11.5 6.1 68.7
bis(2-ethylhexyl)phthalate
1411.3
121.1
141.1 12.1 205.6
butylbenzyl phthalate
3314.7
1119.3
16.7 7.5 100.14
di—n-octyl phthalate
3145.7
129.7
314.6 13.0 103.7
fluorene
86.1 4
27.2
8.6 2.7 25.9
arsenic
30.0
9.3
20.0 6.2 214.0
cadmium
37.6
114.14
22.2 8.5 26.6
chromium
279.1
108.7
111.6 143.5 186.0
copper
1365.14
1109.1
378.1 113.3 630.2
lead
197.2
86.2
157.0 68.6 109.6
mercury
20.14
25.7
6.5 8.2 7.8
nickel
353.1
157.9
282.5 126.3 290.8
selenium
251.9
66.0
2731.0
3.5
0.85
0.37
14.0
16.7
237.9
16.14
3111.5
1.5
0.29
0.15
0.03
14.3
139.9 132.1 167.9
9.14 2.3 18.9
1092.14 121414.6 1365.5
0.3 0.1 1.0
0.09 0.03 0.252
0.014 0.02 0.11
0.1414 0.003 1.32
1.3 0.3 14•7
for secondary.
A_L 10

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The dissolved oxygen in the effluent was assumed to be zero. In the farfield model,
this is represented as a DO deficit loading equal to the axnbi nt DO concentration
multiplied by the discharge flow rate. Average day flows were used, since the
development of DO deficits occurs on a time scale of one to two weeks and short
duration events would not significantly affect DO levels.
The nitrogen loading was computed based on the measured influent Total Kjeidahl
Nitrogen (TKN) concentration of 23 mg/i (MWRA Memo FB2OC). Nitrogen will not be
significantly removed in the treatment process and the loading was therefore
calculated as that concentration multiplied by the discharge flow rate. The average
day, low groundwater flowrate of 390 mgd (17 m 3 /se ) was used, recognizing that high
groundwater conditions provide additional flow without significant additional
load. The NBOD loading was calculated as the nitrogen loading multiplied by Ll.57,
which is the theoretical ratio of NBOD to TKN.
The toxics loadings are highly variable and the corresponding criteria are based on
exceedence frequencies (Section A.2.2.1). To determine these frequencies, both the
mean and standard deviation of the toxics loadings are provided based on measured
influent concentrations and estimated removal efficiencies. Except for PCB’s, these
loadings are the same as those used by MWRA in their analyses (MWRA, STFP V, A,
1987). It is recognized, however, that removal efficiencies will be reduced during
periods of very high flows and the correspondingly higher loadings are also
provided. Further discussion of this factor is provided in Appendix H of this Draft
SEIS.
The PCB loading used by MWRA corresponded to the 1 iig/l concentration of’ Aroclor
12L12 measured in 198 4 (MDC, 19814). This PCB mixture was the only one detected in
the 19814 surveys. In 1986-87, influent surveys conducted by MWRA could not detect
any PCBs. The detection limit for Arocior 12142 was 0.5 iig/i and this value was
therefore used here to. compute a loading. This reduced PCB level is consistent with
observed trends towards decreasing PCB levels in wastewaters and in the environrrent..
A_L u

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A.3.3 TRANSPORT PROCESSES
The transport processes which affect all the constituents are advection (the
transport of dissolved or suspended matter due to the movement of the carrier
fluid), and diffusion (the transport from high to low concentration areas due to
turbulence). These processes assume very different characters in the immediate
vicinity of the outfall structure (discharge nearfield) and farther away from it
(farfield). Different and separate modeling tools are used to analyze these two
regions.
In the discharge nearfield, the effluent undergoes rapid dilution with ambient water
because of shear-induced turbulent entrainment. This dilution is enhanced by
discharge through a multiport diffuser, which distributes the effluent over a number
of individual jets eventually merging into a single line plume. In this region, the
main driving forces are the buoyancy and, to a lesser degree, the discharge momentum
of the effluent. Because of buoyancy, the effluent plume rises through the water
column while entraining ambient water. When the water column is stratified, the
density of the plume may reach that of the ambient because of previous entrainment
of deep, dense ambient waters. In this case, the plume reaches a maximum height of
rise. For unstratified conditions, the plume rises all the way to the water surface
and typically achieves greater dilution. The dynamics of the nearfield plume are
controlled by the diffuser characteristics (primarily its length), the ambient
current speed and direction relative to the diffuser and the ambient density
stratification profile. The time that the effluent spends in the nearfield is
relatively short (on the order of a few minutes) and, therefore, the effects of the
constituent-specific physical, chemical or biochemical reactions is negligible.
The multiport diffuser will be arranged in a line of individual or multiport risers
(Chapter 3). For a given diffuser length to achieve maximum dilution, the port
spacing must be sufficiently small to insure that all the ambient crossflow is
intercepted (Roberts and Snyder, 1987) and optimum dilution of the effluent is
achieved by orienting the diffuser perpendicularly to the ambient current
direction. Hydraulically, the diffuser must be designed to insure sea water
A_142

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purging, uniform flow distribution among ports and sufficient velocities in the
conduit to avoid particulate settling (Fischer et al., 1979).
In the farfield, the diluted effluent is carried by ambient currents, undergoing
additional mixing by dispersion. This stage is largely controlled by the large
scale circulation patterns in the body of water. The effluent becomes mixed
vertically over the water depth. During stratified conditions, the effluent may
remain trapped under the thermocline and, in these critical conditions become mixed
in the lower layer only. This represents the worst conditions in terms of
constituent concentrations and settling, since the water depth is effectively
reduced. On the other hand, the surface waters remain relatively unaffected, with
.associated benefits, such as reduced shoreline impacts. The constituent-specific
physical, chemical or biochemical fate processes also play an important role in the
farfield. These processes are reviewed below for each constituent.
A.3)4 PHYSICO-BlO-CHEMICAL PROCESSES
Dissolved Oxygen (DO, mg/l) is consumed by carbonaceous and nitrogenous biochemical
oxygen demand (CBOD and NBOD, mg/i), sediment oxygen demand (SOD, g/m 2 /day), and
replenished by surface reaeration (or diffusion through the interface for effluent
trapped in the lower layer), and photosynthetic activity (P, mg/l/day).
Mathematically, and independently from transport:
dDO - Kc CBOD - NBOD - SOD + (DOe - DO) + P (A-i)
in which t time
and carbonaceous and nitrogenous BOD decay rates (1/day)
k reaeration (or interfacial diffusion) flux rate (ft/day)
H water depth
DO 5 saturation dissolved oxygen concentration (function of temperature
and salinity)
P net photosynthetic oxygen production rate (mg/i/day)
The carbonaceous and nitrogenous biochemical oxygen demands decay following first
order kinetics:
A- 1 43

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d CBOD - Kc CBOD and d NBOD - NBOD (A-2)
with Kc 0.23 X iO 7 (T_20°C)/day and = 0.1 x 1.O 7(T20° /day,(EPA, 1982)
The surface reaeration flux rate can be estimated by k = (D U/H) 0 5 in which D
molecular diffusion coefficient = 1.7 x m 2 /sec, U = representative velocity and
H = water depth (O’Connor and Dobbin , 1958). Taking U 0.1 rn/sec and H 20 rn
leads to k = 3.0 x 1O 5 rn/sec. When the plume is trapped in the lower layer,
reaeration occurs by diffusion through the interface. Without any BOD loading, the
upper layer remains saturated (actually often supersaturated — Section A.2.2.2) and
Eq. (A-i) is still valid, with k E /h, where h = interface thickness and
vertical diffusion coefficient through the interface, which can be estimated as
follows (Koh and Fan, 1982)
E - - 10 8 h (A-
2 - 1 ao — t o
az p
where p = water density and z vertical coordinate. Taking np/p = 0.002 leads to
k io 6 rn/sec. Following EPA (USEPA, 1982), the sediment oxygen demand can be
estimated by:
SOD = 0.8 a Rd (A- 1 4)
in which a = oxygen:sediments stoichiometric ratio (= 1.07) and Rd = sediment
deposition rate (g/rn 2 /day).
Additional oxygen consumption results from sediment resuspension and is taken into
account separately (A.3.6.1). Photosynthesis is only active during the day and, for
conservativeness, its effects were not taken into account.
Suspended solids (SS, mg/i) remain in suspension because of turbulence. The
vertical distribution of suspended solids depends on the Rouse number Z = w/k ’u*,
where w fall velocity of’ particles, k’ = modified von Karman’s constant ( =0.14)
and u shear velocity (Vanoni, 1975). For low values of Z, as will be the case

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here, the vertical distribution of suspended solids is approximately uniform. Then,
a horizontally two-dimensional simulation approach is justified. The deposition of
solids is controlled by their fall velocity, and can be expressed as follows:
dSS _w (A-5)
dt -R
The fall velocity is a function of the particle sizes, ambient turbulence and
suspended solids concentration, which controls flocculation (Farley, 19814). For a
given range of suspended solids concentrations and ambient turbulence level,
experiments have been conducted to determine the distribution of particle fall
velocities (EPA, 1982; Cardoni et al., 1986). -For the SEIS analyses, three fall
velocities were used: w i. x 10_i cm/see, w = 1 x io2 cm/sec and 1 x
cm/sec. It was assumed that solids with a lower fall velocity effectively do not
settle. The fraction of’ solids in each fall velocity range is given in Table A.3.2
based on EPA, 1982; Cardoni, 1985; MWRA, STFP, V, A, 1987.
TABLE A.3.2 DISTRIBUTION OF DISCHARGED SOLIDS FALL VELOCITIES
Fall
(c
Velocity
rn/see)
Primary
Secondary
lx
1 x
1
10_i
io2
io 3
5%
20%
35%
0%
16%
314%
Does
not settle
1 10%
50%
Nutrients include a variety of elements, the most important of which being nitrogen,
since nitrogen tends to be the limiting nutrient in estuarine and coastal areas
(Appendix C). Nitrogen is supplied by the effluent primarily in the form of ammonia
and, following discharge, undergoes a number of reactions and transformations within
the nitrogen cycle (Najarian and Taft, 1981). During the summer, nitrogen is
recycled very rapidly and it can be assumed that nitrogen is a conservative
substance.
Organic Chemicals discharged in the effluent will be subject to the following
removal processes in the water column: vaporization, hydrolysis, photolysis
biodegradation and adsorption onto suspended solids followed by settling. Each of
A- 1 45

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these processes follows approximately first order kinetics, with a rate constant
dependent on the chemical and numerous other ambient conditions. For each organic
chemical and each process, MWRA estimated a rate constant, from which combined rate
constants were calculated. Based on these, three classes were identified,
characterized by half lives of 20 days, 60 days and no decay, In which the organic
chemicals were placed, (MWRA STFP, V, A, 1987). These estimates were reviewed and
found to provide an adequate characterization of the decay processes. This
classification was therefore used for the SEIS analyses (Table A.3.3).
Inorganic Chemicals, primarily metals, can exist under many different forms,
depending on ambient factors such as pH and li and concentrations, with different
bioavailability and toxicity. The primary physico-chemical fate process undergone
by metals is adsorption to suspended solids followed by settling. The degree of’
adsorption and settling, however, is difficult to predict and, therefore, the metals
were treated as conservative for water column concentration predictions
(Table A.3.3). This is a conservative approach because a significant portion of the
metals were also assumed to be deposited in the sediments (Appendix B and
Section 5.2).
Snwmt ry. The physico-bio-chernical fate processes reviewed above for the different
constituents can all be approximated by first order kinetics with a rate coefficient
(units of 1/time) either constant or equal to a constant flux coefficient (units of
length/time) divided by the water depth. These fate processes must be accounted for
in the farfield modeling where they act as sink terms. The similarity of the
process kinetics allows the same model to be used for all the simulations. The only
exception is DO, which has sinks proportional to the CBOD and NBOD which will need
to have been calculated previously. The farfield model was modified to allow this
computation.
A.3.5 NEARFIELD DILUTION MODELING
A.3.5.1 Model
Several models to calculate the dilution which a municipal effluent undergoes in the
nearfield are maintained by the U.S. EPA (Muellenhoff et al., 1985). Of these
A L$ 6

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TABLE A.3.3 DECAY RATES OF CHEMICAL CONSTITUENTS IN EFFLUENT
20 days
60 days
Constituent half life
half life Conservative
benzene x
bromoethane X
chloroform X
ethylbenzene X
methylene chloride X
styrene X
tetrachioroethylene - X
trichioroethylene X
bis(2-ethylhexyl)phthalate X
butylenzyl phthalate X
di-n-octyl phthalate X
fluorene X
arsenic X
cadmium x
chromium X
copper X
lead X
mercury X
nickel X
selenium x
silver X
zinc X
aldrin X
14)4’-DOT X
dieldrin X
heptachlor x
polychlorinated biphenyls X
(PCBs)
A- 1 47

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models, three are applicable to discharges from niultiport diffusers: UMERGE,
UDKHDEN, and ULINE. The first two are based on the integral approach in which
equations for the conservation of mass, momentum and buoyancy are integrated along
the jet trajectory. ULINE is based on dimensional considerations and laboratory
experiments on line plumes issuing vertically without initial momentum (Roberts,
1979a and 197gb). These three models give initial dilutions results which can vary
by a factor of three. Recent larger-scale laboratory experiments with effluent
discharged horizontally through nozzles can be used to evaluate these models
(Roberts and Snyder, 1985). Based on these experiments, initial dilution estimates
were made for a range of’ conditions representative of the proposed discharge (M’WRA,
STFP V, A, 1987). Comparing model predictions to these estimates showed that both
IJMERGE and UDKHDEN overpredicted dilutions for unstratified conditions by up to
250 percent, but were within 10 percent of measurements for stratified conditions.
The reason is apparently that these models do not properly account for the
interference of jets discharged from separate ports and therefore overpredict
entrainment. In stratified conditions, however, the overpredicted entrainment leads
to an under predicted height of rise and a final dilution close to measurements.
ULINE consistently underpredicted dilutions, with the experiments-based dilution
estimates 60 percent higher than predicted on average.
ULINE was used by MWRA for their analyses, in part because of its conservative
nature (MWRA, STFP V, A, 1987). For the same reason, ULINE was used here.
Sensitivity analyses were however conducted to evaluate the effect that the model
conservatism might have on water quality criteria exceedences.
A.3.7.2 Approach
For each alternate diffuser site, a range of effluent flows, ambient currents arid
stratification conditions were considered. A probability of occurrence was
attributed to each of these parameters, to allow subsequent evaluation of compliance
with toxicity criteria, which involve a frequency of exceedence limit. The effluent
flowrates were the same for all the sites (Table A.3.’ ), based on MWRA estimates
(MWRA, STFP V, A, 1987). For each site, the current speeds used in the simulations
were the 10, 50 and 90 percentile speeds (Table A.2.2) measured at the lower current
meters (since the plume first experiences these currents and may stabilize below the
A- 1 48

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upper current meter in the summer). The corresponding probabilities of occurrence
were taken as 20, 60 and 20 percent respectively (Table A.3.LI). For each site, the
density profiles used in the simulations were based on site-specific temperature and
salinity measurements. These profiles are the same as those used by MWRA for their
analyses (MWRA, STFP V, A, 1987). Their probabilities of’ occurrence were
established based on an analysis of top to bottom density differences from long term
records, as well as the MWRA field program (Table A.3. 1 1).
The discharge depth used at each site was the depth below mean low water minus 1.5 m
to account for riser height (Table A.3.’U. An effluent density of 0.998 g/cm 3 was
used for all cases. Although variations of this parameter are expected during the
year, using a constant value does not introduce significant errors.
The proposed diffusers have a length of’ 2000 m and were assumed to be oriented at
45 degrees to the current, accounting for current direction variability (MWRA,
STFP V, A, 1987). The current scatter plots at the proposed diffuser sites,
however, exhibit a strong biomodality (approximately east—west), suggesting that the
diffusers could be oriented perpendicular to the ambient current for a preponderance
of the time. Another consideration in the selection of a diffuser orientation is to
have the ports at the same elevation, to insure a uniform flow distribution among
all the ports. This would suggest that a preferred orientation is along the depth
contours, which tend to be north—south in the diffuser site areas. An average
orientation close to 90 degrees therefore appears achievable and desirable. This
orientation was therefore also considered in the analyses. A critical design
parameter for the diffuser is its length and sensitivity to this parameter was
investigated by also running the analyses for a 3000 rn long diffuser. The details
of the ports design is not required in this analysis, which assumes that the
diffuser discharge is equivalent to a line source. This requires ports sufficiently
close together (Roberts and Snyder, 1987) and a physical model study should be used
to arrive at the final, port design.
A- 1 49

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TABLE A.3.’4 NEARFIELD SIMULATION CONDITIONS
SITE 2
SITE 14
SITE 5
Current
Current
Current
(m/sec)
Probability
(rn/see)
Probability
(rn/see)
Probability
0.030
0.20
0.01414
0.20
0.014 14
0.20
0.095
0.60
0.128
0.60
0.119
0.60
0.158
0.20
0.232
0.20
0.213
0.20
Density
Density
Density
Profile
Probability
Profile
Probability
Profile
Probability
P1
0.26
P1
0.26
P1
0.26
P2
0.28
P2
0.28
P2
0.28
P3
0.10
P3
0.08
P3
0.08
P14
0.09
p14
0.07
P14
0.07
P5
0.13
P5
0.10
P5
0.09
P6
0.07
P6
0.11
P6
0.08
P7
0.014
P7
0.05
P7
0.07
P8
0.03
P8
P9
0.03
0.02
P8
P9
0.05
0.02
Discharge
Discharge
Discharge
•
Depth
Depth
Depth
m ft
in ft
in ft
22.5 61
28.5 914
33.5 110
ALL SITES
Flowrates
rn/sec
(rngd)
Probability
16.14
(375)
0.35
20.1
(1458)
0.23
27.3
(622)
0.26
37.5
(855)
0.13
149.3
(1126)
0.03
A-SO

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A.3.5.3 Results
For each site and diffuser design, between 120 and 135 ambient conditions were
considered, as described above. The results are summarized in terms of 10, 50 and
90 percentile nearfield dilutions (Table A.3.5), which are minimum dilutions
obtained 10, 50 and 90 percent of the time.
For the 2000 m long diffuser oriented at 115 degrees to the currents (base case),
nearfield dilutions increase from Site 2 to Site 5, as expected. The increase of
50 percentile (median) dilution is 31 percent from Site 2 to 14 and 17 percent from
Site 11 to 5. The 10 percentile dilutions Increase slightly more.
Orienting the diffuser at 90 degrees to the currents increases dilutions by an
average of about 23 percent, with larger increases for the larger dilutions
(90 percentile). This increase can be put in perspective by noting that the Site Lj
diffuser at 90 degrees to the current provides essentially the same dilutions as the
Site 5 diffuser at 145 degrees.
The 3000 m long diffuser at 145 degrees to the currents provides an average increase
of dilution of 33 percent compared to the base case. This option should be
considered as it can potentially be achieved at minimal extra cost by increasing the
port spacing and keeping the same number of ports. The diffuser length cannot be
increased indefinitely with the same number of ports, however, since the port
spacing should remain small enough to intercept all the crossflow. Criteria are
available to establish the maximum port spacing (Roberts and Snyder, 1987).
A.3.6 FARFIELD MODELING
A.3.6.1 Purpose.
Farfield modeling simulates the processes taking place over large distances and time
scales (hours to weeks) after the rapid dilution which occurred in the nearfield.
These processes include transport and physio-bio-chernical processes (A.3.3 and
A.3.14) which need to be simulated to determine I) constituent background build-ups,
A-51

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TABLE A.3.5. NEARFIELD DILUTIONS
Diffuser
Configuration
percentiie(1)
SITE
2
SITE L I SITE
5
2000 in long
10
57
75
92
i45° to
50
98
128
150
currents
90
163
259
272
2000 in long
10
61
79
105
900 to
50
1 1Z I
150
190
currents
90
222
369
388
3000 m long
10
72
91
122
115° to
50
120
159
196
currents
90
232
385
11011
(1) percent of the time
that
the
dilution is less
than the value
indicated.
A-52

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ii) depletion of dissolved oxygen and iii) rates of effluent solids deposition due
to discharge at the alternative diffuser sites.
The criteria compliance assessments (A.3.8) require background concentrations of
effluent constituents as input for determining the frequency of exceedence of’ water
quality criteria at each of the alternative discharge sites. Background build-up of
concentrations develop in the discharge area as a result of the returning ebb and
flood of the tide, which bring previously discharged effluent back in the diffuser
area. The magnitude of the background build-up is determined by a balance of the
input and removal rates of individual constituents. The removal mechanisms are net
drift, horizontal dispersion and natural decay phenomena (A.3.Ll). Perfectly
symmetrical tidal currents do not provide any net removal since their net transport
is zero. The net drift is the result of tidal asymmetries, winds, freshwater
discharges and large scale weather patterns and, as such, is variable in space and
time. Periods of low net drift result in temporarily higher background build-ups
and the duration of low net drift periods is an important factor. The background
build—up is an important element of mixing zone concentrations, as it represents the
ambient water which is used for initial dilution of the effluent in the nearfield.
A.3.6.2 Models and Methodologies.
The hydrodynamic model TEA and companion water quality transport model ELA were
selected for the farfield modeling of this study. These two-dimensional
(vertically-averaged) finite element models account for the location, magnitude and
configuration of alternative effluent discharges, as well as the effects of spacial
and temporal variations in tidal and residual circulation, turbulent diffusion and
constituent decay and sedimentation. TEA is a frequency domain model which solves
for components of water depth and velocity at prescribed frequencies. ELA utilizes
an Eulerian—Lagrangian approach which minimizes numerical dispersion. Detailea
descriptions of TEA and ELA are given in Baptista et al. (198k), Westerink et al
(1985), Kossik et al. (1986), and Baptista (1987). These models permit detailed
resolution of complex coastal geometries as well as refined grid resolution in areas
of special interest at relatively low computational cost.
A-53

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Both TEA and ELA have been applied previously to predict water quality impacts of
wastewater discharges into Boston Harbor and Western Massachusetts Bay. Kossik et
al (1986) developed TEA and ELA models of Boston Harbor and Massachusetts Bay and
calibrated EL.A using results of tracer studies for discharges at the MWRA Nut Island
and Deer Island Primary Treatment Plants. These models were also used by M’WRA for
their farfield analyses of discharge sites in Massachusetts Bay (MWRA, STFP V, A,
1987). The highly resolved model grid used by Kossik et al. (1986) was further
refined in the vicinity of the alternative discharge sites and calibrated using
current meter data from the MWRA field program and a detailed volatile halogenated
organic compounds (VOHC) tracer study (MWRA, STFP V, J, 1987).
The finite element grid used for farfield modeling during unstratified conditions is
the same as that used by MWRA (Figure A.3.1). The TEA grid consists of 1,01414
triangular elements having 628 corner nodes. ELA, which utilizes quadratic basis
functions, requires six nodes per element (three corner nodes and 1 node at the mid-
point of each element side), for a total of 2,309 nodes. The model grid is highly
resolved in Boston Harbor and in the vicinity of the alternative discharge sites,
where concentration gradients are likely to be large. Lower resolution is used in
farther portions of Massachusetts Bay. This grid is more resolved than in any
previous numerical models of Boston Harbor and/or Massachusetts Bay.
TEA and ELA were also used to simulate the water quality impact of the alternative
discharges under vertically stratified conditions, during which the effluent plume
would be trapped below the pycnocline. The MWRA grid was modified for this purpose
by decreasing nodal depths to include only that below a 15 meter-deep pycnocline,
which corresponds to observed summer stratified conditions. As a result, most of
the shallow nodes within Boston Harbor and numerous nodes along the land boundaries
of the original grid were eliminated. The lower layer grid used for simulating
stratified conditions consists of 506 elements, with 293 nodes for TEA and 1,092
nodes for ELA (Figure A.3.2). Only the lower layer was simulated during stratified
conditions, assuming that the effluent remained trapped below the pycnocline. No
exchange with the upper layer was accounted for, resulting in very conservative
results.
A-5 1 4

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GLOUCESTER
PROVINCETOWN
/
FIGURE A.3.1. MODEL GRID FOR UNSTRATIFIED CONDITIONS
BOSTON
OCEAN BOUNDARY
PLYMOUTh
A-55

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GLOUCESTER
MARBLEHEAD
HARBOR
OCEAN BOUNDARY
PROVINCETOWN
PLYMOUTh
HARBOR
FIGURE A.3.2.
MODEL GRID FOR STRATIFIED CONDITIONS
A-56

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Results indicate that constituent concentrations calculated by ELA are sensitive to
the semi-diurnal (M2) tidal currents as well as the non-tidal currents (net drifts)
induced in TEA by specification of a steady (zero frequency) sea-surface slope alorg
the ocean boundary between Gloucester and Provincetown. Concurrently, it was found
that concentrations were insensitive to tidal components other than the semi-diurnal
(142) tide. Accordingly, only the M2 tidal currents and net drifts were simulated in
TEA. Linear and non-linear versions of the TEA model exist. The non-linear
versions account for interactions between different frequencies in bottom friction
and in the generation of other frequencies. For these simulations, a non-linear
version of TEA was used accounting for non-linear bottom friction but not for other
frequencies than zero and the M2 tides. The specification of the ELA ocean boundary
condition for constituent concentrations as either “open” or “closed” has a large
effect on predicted concentrations near the ocean boundary. However, this effect
was not found to be significant for non-conservative constituents near the
alternative discharge sites, which are located sufficiently far from the model ocean
boundary.
The TEA model of Boston Harbor and Massachusetts Bay used to simulate circulation in
non-stratified conditions was recalibrated during preparation of this SEIS to more
accurately simulate the semi-diurnal tidal circulation observed at the MWRA current
meters during the Spring of 1987. The M2 tidal frequency forcings (stage) specified
at the ocean boundary of TEA were recalculated based on a harmonic analysis of the
Provincetown and Gloucester tide gauge data (Table A.2.1). This analysis indicated
that the M2 tidal amplitude at Gloucester is 6 centimeters lower than at
Provincetown with an arrival time 10.6 minutes later than at Provincetown.
Recalibration consisted of comparing M2 tidal ellipses developed from a harmonic
analysis of the MWRA current meter data (A.2.1. 1 ) with simulated M2 tidal ellipses
at corresponding TEA nodes. The bottom friction coefficient used in TEA was then
varied from the value of 0.005 used by MWRA until predicted and observed M2 tidal
ellipses were similar. The bottom friction coefficient leading to the best fit was
0.1. This value is higher than expected but was retained, as the objective was to
correctly simulate observed currents for use in ELA. Recalibrated TEA ellipses are
shown in Appendix A.e.
A-57

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The net drifts calculated using TEA with the original bottom friction of 0.005 and
either a 10 centimeter north-to-south or south—to—north ocean boundary tilt were
found to be similar to long-term average net drifts determined from the 1987 MWRA
current meter data (A.2.1.6). Thus, no further calibration of TEA for steady
residual circulation was necessary. The analysis of net drifts from the measured
data also showed that periods with very low net drifts occurred and, to simulate
those, TEA was also run without ocean boundary tilt.
The above TEA calibration procedure was repeated for the modified TEA grid used to
simulate the lower layer under stratified conditions. For this calibration, the TEA
predictions were compared with tidal ellipses dev eloped from a harmonic analysis of
August, 1987 lower layer current meter data (Attachment A.e). It was found that the
ocean boundary M2 tide amplitude and phase lag used for the TEA simulations of
unstratified cqnditions were suitable for the lower layer simulations. The bottom
friction coefficient which results in the closest agreement between lower layer TEA
predictions and observations was 0.02. The 10 cm north to south and south to north
boundary tilts used for unstratified conditions resulted in residual circulations
under stratified conditions that were similar to the long—term current meters in
August, 1987. Accordingly, non-stratified condition ocean boundary tilts were also
used for stratified conditions.
A.3.6.3 Single Constituents.
ELA was used to simulate both stratified and non-stratified conditions with
discharge of conservative and first-order decaying constituents (20- and 60—day half
lives) at the alternative diffuser sites. These simulations are aimed at the toxic
chemicals; dissolved oxygen and suspended solids are covered afterwards. The
circulation was defined using results of corresponding stratified and unstratified
TEA simulations for the semi-diurnal tide and both zero and average net drift.
Constituent mass loading at each diffuser discharge site was simulated using
20 closely spaced point sources with a total mass flux of 200 mg/sec. This base
rate is the same as that used by MWRA. Because of linearity, concentrations are
proportional to the loading and these base simulations can be used for any
constituent. Results can therefore be converted to individual constituents by
A-58

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multiplying the computed concentrations by the ratio of the actual loading to the
simulated loading of 200 mg/sec.
The modeling approach was to compute “average” concentrations corresponding to
average drift conditions and “worst case” concentrations corresponding to zero net
drift for a period of time. It was noted previously that both north-south and
south-north 10 cm TEA boundary tilts resulted in simulated currents similar to the
average measured net drifts. Circulations computed with these boundary tilts were
therefore used for the “average” condition ELA runs. Simulations were continued
until steady—state, i.e., tidally repeating nodal concentrations were achieved.
This required different simulation lengths, depending on the decay rate.
Predictions of background build-up under the two net drift conditions were found to
be very similar; accordingly, the net drifts used for the simulations was that
predicted by the calibrated TEA model using a 10 cm North-to-South tilt.
The net drift analyses showed that relatively stagnant periods of low drift persist
in Western Massachusetts Bay for up to approximately 10 days (A.2.1.LI).
Accordingly, “worst-case” ELA simulations were conducted using “average”
concentrations as initial conditions and continued for 20 tidal cycles, i.e.,
approximately 10 days with zero net drift.
Contour plots of concentration for all the ELA runs are given in Attachment A.f.
Plots of the results (ng/l) for a conservative tracer under average net drift,
vertically unstratified conditions for Sites 2 and 5 are shown in Figure A.3.3 and
A.3.L respectively. It is seen that the areal extent is larger and the constituent
concentrations are higher at Site 2 than at Site 5.
Background build-ups were determined using concentrations computed with the loading
stopped for one tide cycle before the display time. The background build-up was
taken equal to the average of the corresponding 10 highest nodal concentrations in
the diffuser area, averaged over a tide cycle. This corresponds to an area on the
order of 1.5 2, which is representative of the mixing zone size.
ELA background build-up results are given in Table A.3.6. It is seen that
sensitivity to constituent decay rate is greatest at Site 2 and least at Site 5, but
A—59

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MARBLEHEAD
DIFFUSER SITE 2
UNSTRATIFIED WATER
AVERAGE NET DRIFT
CONSERVATIVE CONSTITUENT
HIGH WATER
20
FIGURE A.3.3. CALCULATED FAR FIELD CONCENTRATIONS (mg/i)
FOR BASE LOADING (200mg/sec)
QUINCY
A-6O

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MARBLEHEAD
DIFFUSER SITE 5
UNSTRATIFIED WATER
AVERAGE NET DRIFT
CONSERVATIVE CONSTITUENT
HIGH WATER
FIGURE A.3.4. CALCULATED FARFIELD CONCENTRATIONS (mg/I)
FOR BASE LOADING (200mg/sec)
NAH ANT
4 ’
QUINCY
A—6 1

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TABLE A.3.6 BACKGROUND BUILDUP (ng/l) FOR BASE LOADING (200 mg/see)
Stratification
Net Drift
Half Life
Site 2
Site J4
Site 5
Unstratified
Average
20 days
60 days
Conservative
125
114i4
158
75
81
86
38
Z40
Iii
Worst
20 days
60 days
Conservative
127
150
166
81
101
108
•68
73
75
Stratified
Average
20 days
60 days
Conservative
1 113
507
550
178
196
208
78
81
83
Worst
20 days
60 days
Conservative
51
5214
576
205
230
2148
123
132
137
A-62

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generally small. Differences between build-up during average and worst-case
stagnant conditions are greatest at Site 5 and least at Site 2 because net drift
currents at Site 2 are lower, and thus closer to no-net drift conditions.
As a check on these background build-up results and to confirm the relative effects
of the controlling processes, the diffuser discharge may be approximated as a source
in a tidal estuary, for which a one-dimensional closed form solution is available.
The concentration at the discharge point is given by the following equation (Fischer
et al., 1979):
C: M - (A-6)
WHUi1 - -
in which M = mass loadings, W : estuary width, U : net current speed, K = decay
coefficient and E : dispersion coefficient. The proposed diffusers are
approximately normal to the net drifts and aligned with the tidal currents. The
above equation, therefore, should provide an approximation of the background build-
up by taking U equal to the net drift speed and W equal to the diffuser length plus
the tidal. excursion (approximate source width). Indeed, equation A-6 provided
estimates of background build-up very close to those predicted by ELA. This
t I
equation shows that for slow decay rates compared to the net drift, i.e. small
ZeKE/U 2 , the background build-up is relatively independent of decay rate. This is
the case for all the diffuser sites, confirming the small predicted changes in
background build-up with decay rates. The net drift is larger at Site 5 so that
4KE/U 2 is smaller, and correspondingly, the change in buildup with decay rate is
smaller at Site 5 than at the other site.
A.3.6. 1 1 Dissolved Oxygen
ELA was modified during preparation of this Draft SEIS to allow simulation of the
impacts of the discharges on dissolved oxygen. The processes of reaeration,
carbonaceous and nitrogenous BOD decay and sediment oxygen demand (SOD) were
included in the model to calculate dissolved oxygen deficits, DOD, below ambient.
Formulation of the mathematical equations controlling these state variables in the
modified ELA model, and the rate constant values used, are discussed in A.3.LI. SOD
values (g/rn 2 /day) were determined using Equation A- 4 with predicted nodal sediment
A-63

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deposition rates (A.3.6.6). Contour plots of dissolved oxygen deficit for primary
treated effluent discharged at Sites 2 and 5, under average net drift, stratified
conditions, are shown in Figures A.3.5 and A.3.6, respectively. Contour plots for
all dissolved oxygen deficit simulations are provided in Attachment A.g. Maximuni
dissolved oxygen deficits, averaged over an area of approximately 1.5
representative of the mixing zone, are listed in Table A.3.7.
TABLE A.3.7 MAXIMUM DISSOLVED OXYGEN DEFICITS (rng/l) 1
Treatment
Stratification
Net Drift
Site 2
Site 14
Site 5
Primary
Unstratified
Average
Worst
0.91
0.92
0.63
0.80
0.21
0.58
Stratified
Average
Worst
11.15
11.22
1.56
1.91
0.39
1.03
Secondary
Unstratified
Average
Worst
0.53
0.514
0.38
0.118
0.1 4
0.35
Stratified
Average
Worst
1.76
1.81
0.69
0.87
0.19
0.116
(1) Averaged over area of approximately 1.5 m 2 , representative of the mixing zone.
A.3.6.5 Sedimentation
Sediment deposition rates were determined for primary and secondary treated effluent
discharges at the alternative sites, under both stratified and unstratified, average
net drift conditions. Simulations were carried out for fall velocities of 0.1, 0.01
and 0.001 centimeters per second until steady state results were achieved and
corresponding total sediment accumulation rates were determined based on the
following equation:
Rd=fl R 1 +f 2 R 2 +f 3 R 3 (A-7)
A-6 1 4

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FIGURE A.3.5. DISSOLVED OXYGEN DEFICIT (mg/i) FOR PRIMARY DISCHARGE
AT SITE 2 UNDER STRATIFIED CONDITIONS, AVERAGE NET DRIFT.
1.0
.5
N
A-65

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FIGURE A.3.6. DISSOLVED OXYGEN DEFICIT (mg/I) FOR PRIMARY DISCHARGE
AT SITE 5 UNDER STRATIFIED CONDITIONS, AVERAGE NET DRIFT.
0.25
2
—66

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in which Rd total sediment accumulation rate (g/m 2 /day), R 1 , R 2 and R 3 predicted
accumulation rates corresponding to 0.1, 0.01 and 0.001 cm/s fall velocities and f 1 ,
and f 3 relative mass emitted with each fall velocity (Table A.3.2). Contour
plots of the resultant sediment accumulation rates for secondary and primary
discharge at Site 5 under stratified conditions are given in Figures A.3.7 and
A.3.8.
A.3.7 SHORELINE IMPACT ANALYSES
A.3.7.1 Concerns
Shoreline concentrations of’ discharged constituents were determined as part of the
farfield modeling. These concentrations were generally small (Attachment A.f).
However, the farfield analyses considered average and zero net drift conditions, the
latter representing worst case conditions relative to background build-up in the
diffuser area. The highest shoreline concentrations can be expected as a result of
sustained net drifts towards shore, most likely due to critical wind events. The
TEA and ELA models are not well suited to simulate these conditions, particularly
because of the frequency domain approach of TEA, which calculates currents only at
pre—specified frequencies. ELA has the capability of adding a uniform net drift to
currents calculated by TEA, but the specification of this net drift based on non-
uniform measured currents is rather subjective. A different model was therefore
used for the shoreline impact analyses.
The worst shoreline impacts will occur when the plume surfaces and is driven to the
shore by ambient current. However, it is conceivable that upwelling of lower layer
waters at the shoreline, due to a combination of’ events, could bring a submer.ged
plume to the shoreline. Simulation of such events would be extremely complex and
was circumvented here by effectively neglecting the protecting influence of
stratification and conducting the same analyses for stratified and non-stratified
conditions.
A-67

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MARBLEHEAD
FIGURE A.3.7. ELA PREDICTED SEDIMENTATION RATES SITE 5,
SECONDARY TREATMENT, STRATIFIED CONDITIONS (g/m 2 /day)
p
BOSTON
HARBOR
NANTASKE1T
DUXBURY
A-68

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MARBLEHEAD
FIGURE A.3.8. ELA PREDICTED SEDIMENTATION RATES, SITE 5,
PRIMARY TREATMENT, STRATIFIED CONDITIONS (gfm 2 /dav)
NAHANT
2.23:
0.6
BOSTON
HARBOR
0.3
NANTASKETF
DUXBURY
A—69

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A.3.7.2. Model and Methodology
The quasi-analytical MIT Transient Plume Model (TPM) was used for these analyses
(Adams et al., 1975). This model simulates a discharge as a succession of puffs
which are individually transported by the current and superimposed for continuous
discharge simulations. An advantage of this approach is that it allows realistic
three-dimensional diffusion of the effluent puffs. The currents used to drive the
model are assumed to be spacially uniform, which is an obvious limitation, but also
permits measured currents to be used, representing actual events.
The discharge is characterized by a volumetric flowrate, Q 0 , and concentration. A
base discharge concentration of 100 was used for the computations so that the
results represent concentrations in percent of the discharge values. The initial
plume depth is assumed constant by the model. Values of this depth, h 0 , for
different ambient current speeds, Ua and nearfield dilutions, Sa were calculated
based on the conservation of mass principal: Ua W h 0 = Sa Q 0 , in which W, the
initial plume width, is equal to the diffuser length plus a small lateral spreading
allowance (W 2050 m). The smallest initial plume thickness of 18 in was used for
the simulations. The initial concentration is calculated by the model from the
discharge concentration provided and the nearfield dilution factor which is assumed
to be proportional to the ambient current speed. A correlation of nearfield
dilution with current speed was developed based on the ULINE model results (5.1.1.L )
and input into the TPM.
A constant lateral diffusion coefficient of 11 m 2 /sec was calculated based on the
4/3 power diffusion model, with a length scale equal to the diffuser length of
2000 m (Csanady, 1980; EPA, 1982). The vertical diffusion coefficient was taken
equal to 5 x 10 m 2 /sec based on Eq. 5-3, with a plume thickness of 18 m and
relative density difference of t pfp 0.000LI. This density difference was
calculated from a relative discharge density difference 0.027, an average nearfieid
dilution of 100 and an average to minimum dilution ratio of 1. 4.
A-70

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A.3.7.3. Results
Analyses were conducted with the Transient Plume Model using MWRA current meter data
for spring and summer 1987 (MWRA, STFP V,G, 1987). Continuous current meter data
for the March-May and June-August periods were input to the model. Simulations of
discharges at each of the three alternative diffuser sites used current records fror
the nearest current meter station. The results of the simulations were examined at
times following periods of sustained net drift towards shore areas. These can be
evaluated using progressive vector plots. An example is shown on Figure A.3.9. The
corresponding plume configuration where shoreline concentrations were high is
presented (Figure A.3.1O). It is important to note that, consistent with the
assumption of uniform currents, shorelines have no effect on circulation and plumes
therefore can extend onto land. The corresponding shoreline concentrations are
therefore conservative estimates of the worst concentrations which might be observed
on shores. Maximum shoreline concentrations at Swampscott, Naharit, Deer Island and
Hull for discharges at the three sites are given in Table A.3.8 for all the current
data available.
A.3.8 CRITERIA COMPLIANCE EVALUATION
A.3.8.1 Dissolved Oxygen
The dissolved oxygen criterion of the applicable Massachusetts Surface Water Quality
Standards is a minimum value of 6 mg/l anywhere in the water column (Table A.2.L ).
Dissolved oxygen deficits have been predicted in the farfield analyses (A.3.6).
Contrary to individual constituents discharged in the effluent, dissolved oxygen
deficits develop over a time scale of several days as a result of the BOD and SOD
exertion. Therefore, the largest DO deficits are obtained through farfield
processes and these are listed in Table A.3.7 for the different sites and operating
conditions. Actual DO levels will be equal to the ambient value minus the DO
deficit. The ambient DO is practically always above 8 mg/i (A.2.2.2) both in the
upper and lower water column. During the fail, however, the ambient DO can drop to
6.5 mg/i or less in the lower layer (A.2.2.2). At that time, however, the
pycnocline is very deep and weak and would not be able to trap the effluent plume in
A—? 1

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SOURCE: MWRA STFPL VOL. V. APP. G. 1987.
FIGURE A.3.9. PROGRESSIVE VECTOR POLl, STATION 4U, AUGUST 1987
I-I I I I I I I I I ’’’’ I ‘‘ • I I I I ‘ ‘ ‘ ‘ I’’’’ I
S 5 IS 2 5 2 5 iS 4 1

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—.- 1
FIGURE A.3.1O. SHORELINE IMPACTS, SITE 4, AUGUST 27, 1987
DEER ISLAND
CONCENTRATION IN PERCENT
A-73

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TABLE A.3.8 MAXIMUM SHORELINE CONCENTRATIONS
(in percent of’ the discharge concentration)
Predicted with Spring and Su er 1987 Current Data.
Area
Site 2
Site i
Site 5
Swarnpscott
0.65
0.58
0.57
Nahant
1.01
0.55
0.58
Deer Island
1.27
0.19
0.214
Hull
0.56
0.32
0.141
the lower layer. The thickness of the lower layer would be about 3m at Site 2 to
13m at Site 5, with strong tidal variations, and these depths are not sufficient to
contain the effluent plume. Therefore, DO values would not be reduced by BOD
exertion from the effluent. The low DO values, however, would be reduced by
resuspension of sediment deposited during the summer and this aspect is considered
separately below.
Outside of resuspension events, therefore, and in areas affected by the effluent, a
low estimate of’ the ambient DO concentration is 8 mg/i and minimum DO levels due to
the effluent are listed in Table A.3.9.
Resuspension Oxygen Demand. Further dissolved oxygen exertion can occur as a result
of sediments resuspension during storms or other events. The dissolved oxygen
demand, RDOD, resulting from a resuspension event can be estimated as follows (EPA.
1982):
S
RDOD 1.6 [ 1 — exp(_Kr t)] (A—8)
in which 5 r averaged concentration in g/m 2 of resuspended organic sediment, based
on a 90-day accumulation, E 2 vertical diffusion coefficient when resuspension iS
occurring (5 x 1O m 2 /sec), Kr decay rate of’ resuspended sediments ( .01/day)
A-7’4

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TABLE
A.3.9 MINIMUM
COLUMN BASED
DISSOLVED OXYGEN
ON A 8.0 mg/i
CONCENTRATIONS
AMBIENT
(mg/i)
CONCENTRATION
iN THE
WATER
Treatment
Stratification
Net Drift
Site 2
Site 14
Site
5
Primary
Unstratified Average
- Worst
7.1
7.1
7.14
7.2
7.8
7.14
Average
Worst
3.9
3.8
6.ii
6.1
7.6
7.0
•
Secondary
Average
Worst
7.5
7.5
7.6
7.5
7.9
7.7
Average
Worst
6.2
6.2
7.3
7.1
7.8
7.5
Stratified
Unstratified
Stratified
A-75

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an t elapsed time following resuspension. The 90-day accumulation of organic
sediments can be evaluated based on the sediment deposition rate, Rd, by:
0.8 R
Sr = kd d [ 1 - exp(- 90 kd)] (A-9)
in which kd is the sediment organic decay rate (kd 0.01/day) (EPA, 1982).
Resuspension events will be associated with extensive turbulence and mixing so that
it is reasonable to use a deposition rate averaged over an area. Using an area of
approximately 5 Lcm leads to the values of Rd listed in Table A.3.8. This area
corresponds approximately to the diffuser length multiplied by the tidal
excursion. The maximum DO depletion, per Eq. A.8 typically occurs at t= 214 hours,
and the corresponding values of RDOD are also listed in Table A.3.1O. These RDOD’s
are exerted over a depth H = 1.6/ E t 10 m from the bottom.
For spring and summer conditions, 8 mg/l represents a low estimate of the ambient DO
and the minimum DO concentration, during a resuspension event, is equal to the
ambient DO minus the farfield DO deficit (Table A.3.7) minus the resuspension DO
demand (Table A.3.10). During the fall, lower layer ambient DO concentrations drop
to about 6.5 mg/i. However, the effluent does not remain trapped in the lower layer
and the minimum DO concentration, during a resuspension event, is therefore equal to
the ambient DO minus the resuspension DO demand (Table A.3.10) only. The
corresponding minimum DOs are listed in Table A.3.11.
The smallest minimum DO concentration is generally obtained for primary effluent, in
stratified, worst net drift conditions, after a resuspension event. These values
can be obtained only once per year, at the eno of the summer and assume the
following combination of events: no resuspension event during 90 days in the
summer, ended by a 10 day period of zero net drift, followed by a resuspension
event. Given the limited expected duration of primary discharge, it is likely that
such an event may never be experienced during 5 years of interim primary discharge.
The results show that the 6 mg/i standard would not be violated at any site for
secondary discharge, except by 0.1 mg/i at Site 2. For primary discharge, the
standard would be violated at Site 2 during resuspension events for both stratified
and non-stratified conditions. At Site 14, the standard would be violated during
A—76

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TABLE A.3.1O SEDIMENT DEPOSITION RATES, R (g/n ’dev)
AND RESUSPENSION OXYGEN DEMANDS, RDOD ( mg/l)
Treatment
Stratification Site 2 Site 11 Site 5
Rd RDOD Rd RDOD Rd RDOD
Primary
Unstratified 2.0 0.62 1.6 0.69 1.3
Stratified 3.5 1.51 2.6 1.12 1.9
0.56
0.82
Secondary
Unstratified 0.31 0.13 0.23 0.10 0.17
Stratified 0.7 0.30 0.115 0.17 0.30
0.07
0.13
(1) Average
over 5 km .
Treatment
TABLE A.3.11 MINIMUM WATER COLUMN DISSOLVED OXYGEN
CONCENTRATIONS DURING RESUSPENSION EVENT (mg/i)
Stratification Net Drift Site 2 Site LI
Site 5
Primary
Unstratified 1 Average 6.5 6.7
Worst 6.5 6.5
7.2
6.8
Stratified 1 Average 2.3 5.3
Worst 2.2 5.0
6.8
6.2
Faii 2 5.0 5.11
5.7
Secondary
Unstratified 1 Average 7.3 7.5
Worst 7. 14 7.11
7.8
7.6
Stratified 1 Average 5.9 7.1
Worst 5.9 7.0
7.7
7.14
Fali 2 6.2 6.3
6.14
(1) Equal to ambient DO (8 mg/i) minus maximum farfield DO Deficit (Table A.3.7)
minus resuspension oxygen demand (Table A.3.8)
(2) Equal to ambient DO (6.5 mg/i) minus resuspension oxygen demand (Table A.3.8).
A-77

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res.ispension events occurring while the water column is stratified. The violations
during resuspension events would be over a depth of approximately 10 m from the
bottom. During fall resuspension events, DO drops to 5.7 mg/i at station 5.
Unfortunately, data are not available to indicate how frequently resuspension events
can occur at the various sites during stratified summer conditions. The large
storms leading to resuspension occur preferentially in the winter and the pycnocline
has an insulating effect which would tend to minimize resuspension.
A.3.8.2 pH.
Changes of pH in the ambient water will arise due to the pH of the effluent and its
-alkalinity. Using a range of ambient water temperatures, carbon dioxide content and
pH, with an effluent alkalinity of’ 0.5 to 1.0 nieq/l and pH of 6.5 to 7.0, MWRA
estimated a range of pH values of 7.6 to 8.28 at the edge of the mixing zone for
secondary effluent discharge. These estimates are based on a minimum nearfield
dilution of’ 10 and are therefore applicable to all sites (MWRA, STFP, V,A, 1987).
For primary effluent discharge changes in ambient water pH were estimated
experimentally by MDC by diluting a mixture of Deer Island and Nut Island effluents
with Massachusetts Bay water in ratios of 20:1, 140:1, 500:1, and 1600:1
(MDC, 19814). The initial pH of the seawater was 8.1 and the measurements indicated
that no significant change occurred for the duration of the tests (19.5 hours). The
minimum pH of any mixture was 7.8.
The Massachusetts Water Quality Standards require the pH to be in the range of 6.5
to 8.5, with a maximum change of 0.2. The analyses and tests described above
indicate that pH values for primary and secondary discharges will be within the
required range at all the alternative diffuser sites. Additional testing is
proposed by MWRA to show that the change will not exceed 0.2. (MWRA, STFP, V,A,
1987).
A-78

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A.3.8.3 Mixing Zone Criteria
The EPA water quality criteria (A.2.2.1) apply at the edge of the mixing zone, which
is defined as the end of the zone of initial dilution, when the plume either reaches
the surface or its maximum height of rise.
Concentrations at the edge of the mixing zone are made up of the following
components: i) nearfield concentration, ii) background build-up, iii) concentration
due to other discharges into Massachusetts Bay and iv) ambient concentration.
Because the dilutions are large, these concentrations are additive at the edge of
the mixing zone.
Nearfield Concentrations are equal to the effluent concentrations divided by
the nearfield dilution, the effluent concentration being equal to the
constituent loading divided by the flowrate. The nearfield dilution depends on
the flowrate, among other parameters, but, it can be assumed that the loadings
are independent of the flowrate, even though at first, high flows during storms
carry higher loads. The probability of any nearfield concentration occurring is
therefore equal to the product of the probabilities of the flowrate, current
speed, stratification profile and constituent loading.
Background Build—up Concentrations were calculated in the farfield modeling for
stratified and non-stratified water columns under average and worst net drift
conditions. Based on a review of the net drift persistence plots
(Attachment A.c), a probability of occurrence of 90 percent was attributed to
the average background build-ups and 10 percent to the worst case build-ups.
Concentrations from Other Sources were calculated by MWRA, accounting for
discharges from Lynn/Saugus, Swampscott, South Essex Sewerage District (SESD)
and the inner harbor combined sewer overflows (CSO’s) (Table A.3.12). Since
these discharges are far from the alternative diffuser sites, their contributio-
is the result of long—term processes and, therefore, average conditions can be
used. These concentrations were obtained through the TEA/ELA farfield models
with loading estimates for each constituent of interest. Values were not
available for some constituents, such as pesticides, and for those, loadings
were taken equal to zero.
A—79

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TABLE A.3.12. EFFLUENT MASS FLUXES (ug/sec) FROM OTHER SOURCES
Sci c’c MU??, TFP \r. 1, 1.31
LYNN
METPLS (Conservative’)
SESD SWAMPSCOTT
KWRA SECONDARY
arsenic
cadmiu m
chromium
copper
lead
mercury
nickel
silver
zinc
selenium
(988 not reported
2€.000 12,100
25,900 23,600
55,100 31,200
172,000 37,100
1.95 11,790
911,000 ND
1,790 ND
3 17,000 117,200
0m9,100 ND
DECAx’ RATE 1 (20
ND not reportec
ND ND
ND ND
BOSTON CSOs
11,325
2,075
10.9140
30.900
77,090
1,373
21,630
1,080
129,300
80,860
<6,730
82.5
2,300
11,700
3,660
211.11
1 ,800
<80.5
73,700
<3,360
day half life)
ND
ND
ND
20,000
22,100
111 ,600
378,100
157,000
6,500
282,500
9, 1100
1,092,1100
1110,000
bromomethane
di-n-octyl phthalate
6 tityl benzylphthalate
bis(2—ethyl hexyl)
phthalte ND ND ND 3,870 111,100
1,600
16, 1 100
2,930
314,600
DECAY
RATE 2 (60
day
half life)
benzene
ND
<585
161
111,020
11,300
chloroform
ND
1l,580
1,200
12,975
11,700
ethy!benzene
ND
(2,880
8.15
2,722
8,800
methylene chlorxoe
ND
<1,880
50.5
3,090
31,600
PCBs
ND
ND
ND
not reported
1,330
Styrene
ND
not
reported
no:
reported
8,96U
19,200
1,1,2,2 tetrachioro-
ethane
h D
ND
13L1
3,952
18,000
tetrachioreothylene
ND
(2,010
ND
L6,180
32,1100
trichioroethylene
ND
.:702
ND
‘3,520
11,500
-50

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Ambient Concentrations represent concentrations presently in Massachusetts Bay
due to previous discharges and other inputs such as sediments. Those are
assumed to be uniform over the Bay and were estimated from measurements far fron
known sources (A.2.2.3). Measurements were not available for all constituents
and zero ambient concentrations were assumed in case of lack of data.
The aquatic life toxicity criteria involve concentrations which should not be
exceeded with a frequency greater than a specified value. For acute toxicity, the
limiting concentrations are the Criteria Maximum Concentrations (CMC) which should
not be exceeded more often than 1 day every 3 years. For chronic toxicity, the
limiting concentrations are the Criteria Continuous Concentrations (CCC), which
should not be exceeded more often than once every 3 years for LI consecutive days.
The CMC and CCC concentrations are listed in Table A.2.5.
In order to evaluate compliance with the aquatic life toxicity criteria, a joint
probability analysis was conducted. The 1 day in 3 years CMC frequency is
equivalent to a probability of occurrence of’ 0.091 percent. Exceedance occurs if a
constituent concentration at the edge of the mixing zone exceeds the CMC for an
entire day, which means that the minimum concentration in that day is above the
CMC. Constituent concentrations at the edge of’ the mixing zone vary as a result of’
variations of the loading, current speed, discharge flowrate, stratification (which
affect the nearfield concentration) and net drift (which affects the background
build—up). Other conditions equal, the minimum mixing zone concentration in a day,
is obtained for the maximum current in that day. During each day, the current
varies due to the tides and the highest current which one can be sure will occur in
any given day is the tidal current amplitude (equal to the half length of the tidal
ellipse). It was noted in A.2.1.LI that the tidal current amplitude was exceeded
between 20 and 50 percent of the time, depending on the station. Therefore, the
50 percentile current is a low estimate of the daily maximum current. And the
corresponding mixing zone concentration is a high estimate of’ the daily minimum
mixing zone concentration. The acute toxicity criterion will be exceeded If’ this
daily minimum mixing zone concentration exceeds the CMC with a frequency greater
than 0.091 percent.
A-8 1

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The procedure utilized to evaluate CMC compliance was therefore to calculate the
daily minimum edge of mixing zone concentration which is exceeded with a frequency
of 0.091 percent. Edge of mixing zone concentrations were calculated using the
50 percentile current speeds for each of the loadings (100 values), discharge
flowrates (5 values), stratification profiles (8 or 9 values depending on the site)
and net drift conditions (average and worst case). Because the highest nearfield
dilutions occur under stratified conditions, the background build-ups corresponding
to stratified conditions were used. The probability of occurrence of each
concentration was calculated as the product of the probability of each of the
controling parameters. The concentrations were then sorted and their probabilities
added, starting from the highest concentration, lntil a cumulative probability of
0.091 percent was obtained. The corresponding concentration was then compared to
the CMC to evaluate compliance.
The discharge flowrates and stratification profiles used in this analysis were those
of the nearfield modeling. The loadings were the )00 consecutive loadings expected
with a 1 percent probability. Assuming a gaussian probability distribution, these
values can be determined from the loading mean, Lm and standard deviation, L 5 :
L = Lm + Zn L 5 (A1O)
in which Z the Z-score of the nth percentile of the gaussian distribution
(Abramowitz and Stegun, 19614). As mentioned in A.3.2, higher loadings were assumed
during storms because of the reduced removal efficiency associated with high
flows. These higher loadings were assumed to occur for the maximum flow of 1126 mgd
used in the nearfield modeling (Appendix H).
The same procedure was used for the chronic toxicity (CCC) compliance evaluation,
but with an exceedence frequency of 0.365, corresponding to 14 days every 3 years.
This approach is conservative I.e. will result in an overprediction of non-
compliance, since the 14 days of exceedance may not be consecutive, as required by
the criterion. Results are in Tables A.3.13 to A.3.15 for both acute and chronic
toxicity compliance.
The human toxicity and carcinogenicity criteria are based on long-term (lifetime)
exposure and fish consumption and, therefore, their compliance was addressed by
comparing the average expected edge of mixing zone concentrations (statistical
A-82

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TABLE A.3.13 AQUATIC LIFE TOXICITY CRITERIA COMPLIANCE FOR SITE 2
COWSTITUENT COWCEMTRATIOW (ug/L)
Mbient Other (1) Acute Toxicity Chronic Toxicity
Conc. Sources ____________________________
Primary Secondary CMC Primary Secondary CCC
benzene 0.016 0.35 0.10 5100.00 0.34 0.10 700.00
bromom thane 0.001 1.26 0.24 12000.00 1.20 0.23 6400.00
chloroform 0.015 0.53 0.21 0.50 0.20
ethytbenzene 0.003 0.77 0.18 430.00 0.72 0.17
methyLene chloride 0.004 3.08 1.33 12000.00 2.85 1.23 6400.00
styrene 0.022 0.80 0.21 430.00 0.77 0.20
tetrachloroethytene 0.053 1.55 0.38 10200.00 1.44 0.36 450.00
tr lchloroethyLene 0.015 0.84 0.25 2000.00 0.79 0.23
bis(2-ethylhexyl)phthalate 0.002 1.53 0.60 2944.00 1.46 0.57 3.40
butyLbenzyt phthalate 0.007 1.35 0.31 2944.00 1.27 0.29 3.40
di noctyl phthaLate 0.002 1.34 0.31 2944.00 1.27 0.29 3.40
fluorene 0.0013 0.33 0.08 300.00 0.31 0.07
arsenic 0.498 0.019 0.65 0.60 69.00 0.64 0.60 36.00
ca&iiun 0.006 0.049 0.22 0.15 43.00 0.21 0.15 9.30
chrcmiun 0.316 0.074 1.63 1.04 1100.00 1.57 1.01 50.00
copper 0.074 0.184 6.08 2.43 2.90 5.87 2.34
lead 0.091 0.466 1.45 1.27 140.00 1.41 1.23 5.60
mercury 0.004 0.007 0.136 0.051 2.100 0.126 0.047 0.025
nickeL 0.604 0.203 2.41 2.09 75.00 2.34 2.03 8.30
seleniun 0.273 1.66 1.04 760.00 1.55 0.98
silver 0.005 0.28 0.07 2.30 0.27 0.07
zinc 0.810 0.949 17.84 8.19 170.00 16.38 7.67 58.00
aldr in 0.02 0.00 1.30 0.01 0.00
4,4’•DDT 0.004 0.001 0.130 0.004 0.001 0.001
dieldrin 0.0017 0.0004 0.4100 0.0016 0.0004 0.0019
heptachlor 0.0127 0.0036 0.0530 0.0126 0.0036 0.0036
polychioririated biphenyls 0.0073 0.074 0.022 0.071 0.022 0.030
(1) Refer to text for explanation
A-83

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TABLE A.3.16 AQUATIC LIFE TOXICITY CRITERIA CCPSPLIANCE FOR SITE 4
00NSTITUENT 00WCENTRATIOWS Ci /L)
Ajibient Other (I) Acute Toxicity Acute Toxicity
Conc. Sources ____________________________ ____________________________
Prlmery Socordary CMC Primery Secordary CCC
benzene 0.011 0.21 0.05 5100.00 0.20 0.05 700.00
bromometharie 0.000 0.80 0.13 12000.00 0.72 0.11 6400.00
chLoroform 0.010 0.33 0.11 0.29 0.10
ethylbenzene 0.002 0.47 0.09 430.00 0.42 0.08
methylene chLoride 0.002 1.97 0.69 12000.00 1.69 0.59 6400.00
styrene 0.014 0.48 0.11 430.00 0.44 0.10
tetrechioroethy lene 0.035 0.98 0.21 10200.00 0.86 0.18 450.00
trichioroethytene 0.010 0.53 0.13 2000.00 0.46 0.11
bis(2-ethy lhexy l)phtha let 0.001 0.97 0.31 2944.00 0.88 0.28 3.40
butylbenzyl phthalate 0.004 0.87 0.16 2944.00 0.77 0.14 3.40
dl noctyL plithatete 0.001 0.86 0.16 2944.00 0.77 0.14 3.40
fluorene 0.21 0.04 300.00 0.19 0.04
arsenic 0.50 0.015 0.59 0.56 69.00 0.58 0.56 36.00
cedniun 0.01 0.035 0.14 0.10 43.00 0.13 0.09 9.30
chrcnthsi i 0.32 0.054 1.11 0.69 1100.00 1.04 0.67 50.00
copper 0.07 0.136 3.66 1.27 2.90 3.36 1.19
teed 0.09 0.336 0.97 0.86 140.00 0.91 0.81 5.60
mercury 0.004 0.005 0.092 0.035 2.100 0.078 0.031 P2
nickeL 0.60 0.144 1.72 1.52 75.00 1.61 1.44 8.30
seLeniun 0.199 1.09 0.70 760.00 0.96 0.62
siLver 0.004 0.17 0.04 2.30 0.15 0.03
zinc 0.81 0.697 12.06 5.73 170.00 10.44 5.08 58.00
a ldriri 0.000 0.01 0.00 1.30 0.01 0.00
4 1 4’-DDT 0.0022 0.0004 0.1300 0.0020 0.0004 0.0010
dieldrin 0.0010 0.0002 0.4100 0.0009 0.0002 0.0019
heptech lor 0.0081 0.0019 0.0530 0.0076 0.0017 0.0036
polychtorfriated biphenyts 0.0073 0.0472 0.0147 0.0439 0.0141 0.0300
(1) Refer to text for explanation
A-8 1 4

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TABLE A.3.15 AQUATIC LIFE T ICITY CRITERIA PLIANCE FOR SITE 5
00NSTITUENT 00NCENTRATIONS ( /L)
Athient Other (1) Acute Toxicity Chronic Toxicity
Conc. Sources ____________________________
Primery Secondary DIC Primary Secondary CCC
benzene 0.007 0.15 0.03 5100.00 0.14 0.03 700.00
br w .athane 0.000 0.60 0.08 12000.00 0.51 0.07 6400.00
chloroform 0.006 0.24 0.07 0.20 0.06
ethylbenzene 0.001 0.35 0.06 430.00 0.29 0.05
methylene chloride 0.001 1.48 0.43 12000.00 1.16 0.35 6400.00
styrene 0.009 0.35 0.07 430.00 0.31 0.06
tetrachloroethylene 0.022 0.73 0.13 10200.00 0.58 0.11 450.00
tr chloroethylene 0.006 0.39 0.08 2000.00 0.32 0.07
bis(2-ethyLhexyl)phthalat 0.001 0.73 0.20 2944.00 0.63 0.17 3.40
butylbenzyl piithalate 0.002 0.66 0.10 2944.00 0.54 0.09 3. O
dI•n-octyl phthatate 0.000 0.65 0.10 2944.00 0.54 0.09 3.40
fluorene 0.001 0.16 0.03 300.00 0.13 0.02
arsenic 0.498 0.011 0.56 0.55 69.00 0.56 0.54 36.00
cadnlun 0.006 0.025 0.10 0.07 43.00 0.09 0.07 9.30
chroiniun 0.316 0.040 0.89 0.57 1100.00 0.80 0.55 50.00
copper 0.074 0.098 2.64 0.87 2.90 2.29 0.79
lead 0.091 0.238 0.72 0.64 140.00 0.65 0.59 5.60
mercury 0.004 0.004 0.072 0.028 2.100 0.054 0.023 0.025
nickel 0.604 0.101 1.41 1.27 75.00 1.29 1.17 8.30
seleniun 0.141 0.82 0.52 760.00 0.65 0.43
silver 0.003 0.12 0.02 2.30 0.10 0.02
zinc 0.810 0.498 9.31 4.52 170.00 7.28 3.70 58.00
aldrin 0.01 0.00 1.30 0.01 0.00
4 1 4’•DDT 0.0016 0.0003 0.1300 0.0013 0.0002 0.0010
dieldrin 0.0007 0.0001 0.4100 0.0006 0.0001 0.0019
heptachtor 0.0060 0.0012 0.0530 0.0054 0.0010 0.0036
polychlorinated biphenyls 0.0073 0.036 0.012 0.033 0.011 0.030
Cl) Refer to text for explanation
A -85

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expected values) to the criteria concentrations. Results are in Table A.3.16 to
A.3. 18.
The criteria exceedances, for both aquatic life and human health, are summarized in
Table A.3.19 in terms of the ratio of the computed concentration to the criterion
concentration. Only the concentrations leading to criteria exceedences (ratio
greater than 1.0) are listed in the table. This table shows that some of the
exceedances are by a small amount and others by several orders of magnitude.
Criteria exceedances by ambient waters are also noted. This is the case for the
arsenic and PCBs carcinogenicity criteria. In both cases, however, the criterion
would be exceeded because of the discharge, even in absence of any ambient
concentration.
Table A.3.19 shows that for secondary treatment, Site 5 does not exceed any aquatic
life criterion and exceeds 5 human health criteria at the i0 risk factor. At the
10 risk factor, Site 5 exceeds two human health criteria (arsenic and PCB’s),
which are already exceeded by the ambient. Site L exceeds one more criterion than
Site 5 (CCC Mercury). For primary treatment a larger number of criteria exceedences
occurs: 12 for Sites 2 and LI and 11 for Site 5.
A -86

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TABLE A.3.16 *J AW HEALTH CRITERIA cORPLIAJICE FOR SITE 2
cOkSTITL NT NcENTRATICSIS (I II)
fent Other (1) Toxicity Carcinogenicity
Conc. Sources 1O •5 1O’ -6
Primery secondary Criteria Criteria Criteria
benzene 0.016 0.28 0.03 400.00 40.00
brQsi ethane 0.001 0.88 0.05 157.00 15.70
chloroform 0.015 0.37 0.05 157.00 15.70
•thytbenzene 0.003 0.53 0.03 3280.00
methylene chlorIde 0.004 1.90 0.13 157.00 15.70
styrene 0.022 0.61 0.08 3280.00
tetrachloroethyLene 0.053 1.03 0.16 88.50 8.85
tr ichioroethyLene 0.015 0.57 0.05 807.00 80.70
bIsC2•ethylhexyL)phthaLat 0.002 1.11 0.12 500000.0 500D0.0
butylbenzyl phthaLate 0.007 0.91 0.06 0.00 0.00
di•n-octyl phthaLete 0.002 0.93 0.10 0.00 0.00
fluorene 0.001 0.233 0.026 0.311 0.0311
arsenic 0.498 0.019 0.614 0.582 0.175 0.0175
ca&miun 0.006 0.049 0.18 0.13
chrom lumi 0.316 0.074 1.29 0.76
copper 0.074 0.184 4.66 1.50
lead 0.091 0.466 1.19 1.06
mercury 0.004 0.007 0.077 0.032 0.146
nickeL 0.604 0.203 1.94 1.72
selenlun 0.273 1.08 0.73
s lIver 0.005 0.22 0.04
zinc 0.810 0.949 10.56 5.30
atdrin 0.01052 0.00111 0.00079 0.000079
4,4’ DDT 0.00274 0.00029 0.00024 0.000024
dleldrin 0.00119 0.00013 0.00076 0.000076
heptach lor 0.01063 0.00125 0.00290 0.000290
polychloririated biphenyls 0.00730 0.05747 0.01160 0.00079 0.000079
(1) Refer to text for explanation
A-87

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TABLE A.3.17 HLJIAN HEALTH CRITERIA CORPLIANCE FOR SITE 4
cONSTITUENT cONCENTRATIONS (u Il)
* i.nt Other (1) Toxicity Carcinogenicity
Conc. Sources 1O -5 10 -6
Pri ry Secondary Criteria Criteria Criteria
benzene 0.011 0.13 0.02 400.00 40.00
bramiomethane 0.000 0.42 0.02 157.00 15.70
chloroform 0.010 0.17 0.03 157.00 15.70
ethytbenzene 0.002 0.24 0.02 3280.00
aethytene chloride 0.002 0.86 0.06 157.00 15.70
styrene 0.014 0.28 0.04 3280.00 0.00
tetrachloroethylerie 0.035 0.48 0.08 88.50 8.85
tr ichloroethy tene 0.010 0.26 0.03 807.00 80.70
b$s(2•ethythexyt)phthalat 0.001 0.52 0.06 500000.0 50000.0
butyLbenzyL phthatate 0.004 0.43 0.03 0.00
dl-noctyt phthatate 0.001 0.44 0.05 0.00
fluorene 0.001 0.000 0.111 0.013 0.311 0.0311
arsenic 0.498 0.015 0.556 0.542 0.115 0.0175
cadith.in 0.006 0.035 0.09 0.07
dircmiun 0.316 0.054 0.77 0.53
copper 0.074 0.136 2.15 0.76
teed 0.091 0.336 0.71 0.65
ercury 0.004 0.005 0.038 0.018 0.146
nickel 0.604 0.144 1.25 1.15
selenn,n 0.000 0.199 0.56 0.40
silver 0.000 0.004 0.10 0.02
zInc 0.810 0.697 5.39 3.07
•tdr ln 0.00476 0.00050 0.00079 0.000079
4,4 t •D OT 0.00121 0.00013 0.00024 0.000024
dietdriri 0.00053 0.00006 0.00076 0.000076
heptachtor 0.00502 0.00059 0.00290 0.000290
potychioririated biphenyls 0.00730 0.03000 0.00924 0.00019 0.000079
Cl) Refer to text for explanation
A-88

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TABLE A.3.18 *J AW HEALTH CRITERIA PLIAJICE FOR SITE 5
NSTITLJENT WCENTRATIOSIS (i. /t)
A ient Other (1) Toxicity Cercinogenicity
Conc. Sources 10 -5 10-6
Primery Secardary Criteria Criteria Criteria
benzene 0.007 0.07 0.01 400.00 40.00
br m ....ethane 0.000 0.24 0.01 157.00 15.70
chloroform 0.006 0.09 0.02 157.00 15.70
•thylbenzene 0.001 0.13 0.01 3280.00
ethylene chloride 0.001 0.47 0.03 157.00 15.70
styrene 0.009 0.15 0.02 3280.00
tetrachLoroethylene 0.022 0.26 0.05 88.50 8.85
tr chloroethylene 0.006 0.14 0.02 807.00 80.70
bisC2-ethylhexyo)phthelat 0.001 0.30 0.03 500000.00 50000.00
butyLbenzyl phthalete 0.002 0.24 0.02
dln-octyl phthalete 0.000 0.25 0.03
fluorine 0.063 0.008 0.311 0.0311
•rsenlc 0.498 0.011 0.531 0.524 0.175 0.0175
cadelun 0.006 0.025 0.06 0.05
chromiun 0.316 0.040 0.56 0.44
copper 0.074 0.098 1.19 0.46
lead 0.091 0.238 0.48 0.45
mercury 0.004 0.004 0.02 0.01 0.146
nickel 0.604 0.101 0.97 0.92
selenlun 0.000 0.141 0.33 0.25
silver 0.000 0.003 0.05 0.01
zInc 0.810 0.498 3.35 2.13
aldrln 0.00258 0.00027 0.00079 0.000079
4,4’•DDT 0.00064 0.00007 0.00024 0.000024
d leldrin 0.00028 0.00003 0.00076 0.000076
heptach(or 0.00284 0.00033 0.00290 0.000290
polychtorinated biphenyLs 0.00730 0.01959 0.00835 0.00079 0.000079
(1) Refer to text for explanation
P -89

-------
TABLE A.3.19 SUMMARY OF PREDICTED WATER QUALITY CRITERIA EXCEEDANCES
Criterion
Constituent
Ambient
CONCENTRATION/CRITERION
Primary
RATIOS 1)
Secondary
Site 2
Site 14
Site 5
Site 2
Site 14
Site 5
CMC
copper
2.1
1.26
CCC
heptachior
3.119
2.11
1.51
1.01
I l, 1 4’-DDT
3.55
1.99
1.311
mercury
11.96
3.114
2.18
1.90
1.26
PCBs
2.37
1.116
1.09
Carcinogenicity
(1O risk factor)
aidrin
13.30
6.02
3.26
1.111
14, P-DDT
11.110
5.014
2.65
1.21
heptachior
3.66
1.73
dieldrin
1.57
arsenic
2.85
3.51
3.17
3.011
3.32
3.09
2.99
PCBs
9.2 14
72.75
38.00
214.80
114.69
141.70
10.57
(io 6 risk factor)
aldrin
133.1
60.23
32.11
111.08
6.35
3. 143
L 1,L I’..DDT
1114.1
50.38
26.146
12.08
5.33
2.79
heptachior
36.611
17.30
9.81
4.30
2.03
1.15
dieldrin
15.68
6.92
3.63
1.66
flourene
7.50
3.56
2.011
arsenic
28.115
35.07
31.75
30.37
33.25
30.95
30.814
PCBs
92.140
727.50
379.78
2147.96
1146.86
117.00
105.70
‘1’ Concentration
‘ / Criterion
A-gO

-------
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Adams, E. E., R. F. Kossik, and A. M. Baptista, 1986. Source Representation in a
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Alarn, A. M. Z., D. R. F. Harleman, and J. M. Colonell, 1982. Evaluation of Selected
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Bigelow, H. B., 1927a. Dynamic Oceanography of the Gulf of Maine, Bulletin of the
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Brooks, Norman H., 1987. Seawater Intrusion and Purging in Tunnelled Outfalls - A
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Butman, B., 1971. Some Short Term Current Observations in Massachusetts Bay.
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A-9 1

-------
Butman, B., 1987. Observations of Currents and Sediment Movement in Western
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Cardoni, J.J., Bingham, D.R. and Baratta, N.D., 1986. Determining Settling
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Conference.
Christodoulou, G. C., J. J. Connor, and B. R. Pearce, 1976. Mathematical Modeling
of Dispersion in Stratified Waters, Technical Report No. 219, R. M. Parsons
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Csanady, G. T., 1980. Turbulent Diffusion in the Environment, Geophysics and
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EG&G, 1976. Forecasting Power Plant Effects on the Coastal Zone. Report No. B- 1 4 1 41
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Waltham, MA.
Farley, K.J., 198 4. Sorption and Sedimentation as Mechanisms of Trace Metal
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Issacson, M.S., Koh, R.C.Y. and Brooks, N.H., 1983. Plume Dilution for Diffuser
with Multiport Risers, ASCE, Journal of Hydraulic Engineering, Vol. 109, No. 2.
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Kossik, R. F., P. M. Gschwend, and E. E. Adams, 1986. Tracing and Modeling
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Leimkuhler, W., J. J. Connor, J. C. Wang, G. Christodoulou, and S. Sundgren, 1975.
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MDC, 1979. Application for Modification of Secondary Treatment Requirements for
Discharge into Marine Waters of Boston Harbor and Massachusetts Bay for its
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and Deer Island Treatment Plants, Volumes I-IV. MDC. Boston, MA.
A-92

-------
MDC, September l98L b. Application for a Waiver of Secondary Treatment for the Nut
Island and Deer Island Treatment Plants, Summer Supplement. MDC. Boston, MA.
MDC, 198Z d. Boston Harbor Data Management File. Prepared for U.S. EPA, Region I.
Environmental Evaluation Section, Water Management Division, (Contract No.
68 _OZI_lOog, Boston, MA.
MWRA, STFP III, 1987. Secondary Treatment Facilities Plan, Volume III, Treatment
Plant. Massachusetts Water Resources Authority MWRA). Charlestown 1 MA.
MWRA, STFP V, 1987. Secondary Treatment Facilities Plan, Volume V, Effluent
Outfall.
MWRA, STFP V,A, 1987. Secondary Treatment Facilities Plan, Volume V, Appendix A,
Physical Oceanographic Investigations. -
MWRA, STFP V,B, 1987. Secondary Treatment Facilities Plan, Volume V, Appendix B,
Chemical and Biological Oceanography.
MWRA, STFP V,D, 1987. Secondary Treatment Facilities Plan, Volume V, Effluent
Outfall, Appendix D, Conceptual Diffuser Design.
MWRA, STFP V,E, 1987. Secondary Treatment Facilities Plan, Volume V, Appendix E,
Engineering Analysis of Alternative Outfall Systems.
MWRA, STFP V,G, 1987. Deer Island Secondary Treatment Facilities Plan, Volume V,
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Manohar-Maharaj, V. and Beardsley, H. C., 1973. Spring Runoff in Massachusetts
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Mayer, D. A., 1975. Examination of Water Movements in Massachusetts Bay. Technical
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Muellenhoff, W. P., A. M. Soldate, D. J. Baurngartner, Jr., M. D. Schuldt, D., L. R.
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A-93

-------
O’Connor, D.J. and Dobbins, W.E., 1958, Mechanisms of Reaeration in Natural Streams,
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Roberts, P. J. and W.H. Snyder, 1987. Merging Buoyant Jets in a Stratified
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Vanoni, V.A., 1975. Sedimentation Engineering, American Society of Civil
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of’ Hydraulic Engineering, Vol. 110, No. 2.
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Outfalls, ASCE, Journal of Hydraulic Engineering, Vol. 1114, No. 2.
A- 914

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ATTACHMENT A.a
MONTHLY AVERAGED CURRENTS
FROM MWRA PROGRAM

-------
These monthly averaged currents represent vectorial net currents at the current
meter stations (indicated by a dot at the base of the vectors) over the indicated
month. The length of each vector is proportional to the net current speed, which is
also indicated. The arrows do not represent the path a particle would take if
released at the meter station. The monthly averaging removes tidal influences and
provldes an indication of overall net current patterns and net drifts. These data
are further discussed in A.2.1.LL.

-------
KAtP AY
• POO(
NORTH
O SALEM
P44J BLENE4D
SWAMPSc
LEGEND
O
• N4J 4.NTMY ocrry VECTOR
____t OJ EW7 ETER
PJ,&JW4T VELOCiTY VECTOR
BROAD SO VJ .cAc Ls •Trs
I / MY
W M OP
/
/ 2.4 CMSEC
5.5CMSEC
2.7 CMSEC
BOGION’
7
1
40 CMSEC
MSEC 4.0 CMSEC
I
I
BIGHT
QUINCY .
U • COHASSET:
0 .: •• A E S ‘
FIGURE A.a.1. VECTOR CURRENT AVERAGES FOR MARCH 1987
SALEM
SOURCE: MWRA, STFP VOL. A, 1987

-------
NOr TH, SALEM
O SALEM S0.A’D
HALFWAY
• DCK
MLEHE AD
• .
• SWAMPSC ’TT.
LEGEND
— — L MER L 4T $ €1ER
N4J 4NTMY VELOcITY VEC1OR
____ LJ P a i i rE
B/ O4.D &DL M WTS
/
1 2.6 CMSEC MV
— . MSEC
3.6 CMSEC
/
gh4/16 1.8CMSEC
B fl /
1.5cMSEG.
• NANTA9 7 ‘
• ROADS
5.8 CMSEC
NANTA T
Q N
V... .KLOME1E S
• • . A E MI S 5 S ATh
SOURCE: MWRA, STFP VOL. A, 1987
FIGURE A.a.2. VECTOR CURRENT AVERAGES FOR APRIL 1987

-------
NO TH .
0 .
SALEM
MA
SWAMPSCOTT
L N
N4JWITMY
NTH OP )
• - 1.3 CMSEC
/
3.3 CMSEC
RALP AY
‘I
It’
‘I
I
I
I’
I
I
I
8.5 CMSEC
I
I
I v ’(ASSACH JSE7TS
B4V
Q NCY
I - * r— IQLOME1Ef CO .t* E•T
A E M . I S A
SOURCE: MWRA, STFP VOL. A, 1987
- LEGEND
L R C I TER
vaocrry VECTOR
______ L EPI Qi 9 PET I
TY VECTOR
FIGURE A.a.3. VECTOR CURRENT AVERAGES FOR MAY 1987
)
0.7 CMSEC
I ‘
\ 72cMSEC
4.0 CMSEC
/
‘4
N
‘ 4
‘47
2.6 CMSEC
MAY16
¶.J 10
MMA9 T
3.2 CMSEC
ROADS

-------
)
LEG FND
4 ’ .
NORTH -
O SALEM
HALFWAY
MJ&ENEAD
LO R a N’r P €TER
• SWAMPSCOTT v ocrr VECTOR
VELOCrTY VECTOR
LYNN
MHAWTMY —
aaam c
• c icTa
3.0a U M
AD (XO \
2 BAY
WNTHPOP
/1 4 an sc
- /
• •. ‘
/
BOGT i s a 2 k
1’ \
• •• 52 an
ROADS
NANTA% T

0 SIATLITE MILES • SE..
FIGURE A.a.4. VECTOR CURRENT AVERAGES FOR JUNE 1987
SOURCE: MWRA. STFP VOL. A. 1987

-------
NO TH
S LEM
U
L ,J HALFWAY
•POC3<
MARBLEHEAD
I
SWAMPSCOTT
• L N
• NAUA ’ ITMY k
I A ai
‘ L4 a V
13a c
8RQADSO(J M4. Act FrTs
• : WT OP• 43 L
/ fIAav
• I 2.Ocm1.s 29aMs
lii
I S
_ 2 tsc
LEGEND
• VELOCfT ’Y VECTOR
_ R C ET
• . .OClTY VECTOR
LOMETERS :
• • . •. 0 STATUTE MLES
SOURCE. MWRA, STFP VOL. A, 1987
FIGURE A.a.5. VECTOR CURRENT AVERAGES FOR JULY 1987
5’
NA A 7

-------
0.
MA
¼2 an/ êTb
It
S
KALFWAY
po
NORT
SALEM
SWAMPS OTT
LVNN
N4J 4 .NTMV
1.1a Vssc
2iam’
a4 csc MAAC 1 L E7TS
4b
1 .5 aMsc SAY
5 I..
WNTI4 OP 10.5 _.
• . 2. aTb tO CTbW C
DEEP
SAND
/
• 3Oam
OUT SOENT •‘l\ 3 7 /
Z
N’ A9 7
• . RQADS
• QUNCi’- -\_)
c •• . K OMET S COASSEI
lUTE MILES SCITUATE
SOURCE: MWRA. STFP VOL. A. 1987
FIGURE A.a.6. VECTOR CURRENT AVERAGES FOR AUGUST 1987
LEGEND
a
.ocrr ’ VECTOR
IPPER hET
VELOCITY VECTOR

-------
ATTACHMENT A b
TIDAL ELLIPSES
DETERMINED FROM MWRA CURRENT MEASUREMENTS

-------
Tidal ellipses are the locus of’ the end of the velocity vector at the measurement
point as a function of time. The u and v components of velocity are west to east
and south to north respectively. The length of the long axis of’ the ellilpse
represents the tidal current amplitude and the width is a measure of the tidal
current rotation. Rectilinear tidal currents would lead to tidal ellipses
degenerated to straight line segments. These tidal ellipses were used in A.2.1i to
characterize the current regimes of the sites and in A.3.6 to calibrate the
hydrodynainic farfield model, TEA. A comparison of’ tidal ellipses from the
calibrated model and the measurements is provided in Appendix A.e.

-------
U)
0
>
NO DATA FOR AUG87
0
0
0
0
0
8
0
0
0
U)
0
- o.oo
STATION1MAR.-MAY87
—io.oô
0.00
U (CM/S)
10.00
20.00
FIGURE A.b.1. TIDAL ELLIPSES AT MWRA STATION 1

-------
NO DATA FOR MAR-MAY 87
(no
0
S . —
>
U (CM/S)
FIGURE A.b.2. TIDAL ELUPSES AT MWRA STATION 2

-------
0
0
0
I-
0
0
It ,
STATION 3 MAR.
. MAY
87
a_
I I I I I . . . . . . . . I —
—10.00 0.00 10.00 20.00
U (CM/S)
(1)0
0
>
- 0.00
0
0
0
U)
0
>
U (cM/s)
FIGURE A.b.3. TIDAL ELLIPSES AT MWRA STATION 3

-------
NO DATA FOR MAR-MAY 87
0
0
0
C / )
0
>
U (CM/s)
FIGURE A.b.4. TIDAL ELLIPSES AT MWRA STATION 4

-------
0
0
,-
8.
1)
0
0
In.
STATION 5 MAR. . MAY 87
I I I I I n I I I
—
I I I I I
—10.00 0.00 10.00 20.00
0
4.00
C,,
0
>
U’
0
>
U (CM/S)
0
0
0
U (cM/s)
FIGURE A.b.5. TIDAL ELLIPSES AT MWRA STATION 5

-------
NO DATA FOR MAR-MAY 87
0
0
0
(n
0
U (cM/S)
FIGURE A.b.6. TIDAL ELLIPSES AT MWRA STATION 6

-------
FIGURE A.b.7. TIDAL ELLIPSES AT MWRA STATION 7
0
0
0
( 1)
0
>
0
0-
U,
0
0
-
It,
STATION MAR.- MAY 7 •
0
— 0.o0
—10.00 0.00 10.00 20.00
U (cM/S)
8
0
0
>
0
0.
It,
—___


0
0
U,
STATION7AUG.,87 . . .
- -

. , I .
0
- 0.00
—10.00
0.0o
U (cM/s)
10.00
20.00

-------
(1)
0
>
FIGURE A.b.8. TIDAL ELLIPSES AT MWRA STATION 9
0
0
0
0
0
C 4
—
—
—
-
0
0
0-
-
c
STATION 9 MAR. . MAY 87
I I I I I . . I I
I I I I I
0
- o.00
0
0
—40.00 0.00 40.00
U (cM/s)
80.00
(I)
0
>
!:
,/l1
;.z
. .
STA11ON 9 AUG. 87
I I I I I • • i I
I I I I I t • I
10.00 —40.00 0.00 40.00 80.00
U (CM/S)

-------
FIGURE A.b.9. TIDAL ELL SES AT MWRA STATION 10
0
0
0
0
0
V ) 0
0
>
0
0
0
0
0
STATION 10 MAR. . MAY 87
I . .
40.00
80.00
-10.00 —40.00
U (cM/s)
0
0
?
0
0
0
c 4
(I)
0
>
STATION1OAUq.87
.1....
0
0
0
0
0
0
c 1
0
- 0.00
—40.00 0.00 40.00 80.00
U (cM/S)

-------
ATTACHMENT A.c
NET DRIFTS
COMPUTED FROM MWRA CURRENT MEASUREMENTS

-------
Net drifts are currents superimposed on the tidal currents, leading to any net
transport. The net drifts in these plots were obtained by taking the vector average
of the measured currents over exactly 10 tide cycles. At each point in time the
indicated magnitude and direction of the net drift corresponds to the average
current over the following 10 tide cycles. The plots in effect show running
averages of the measured currents. Net drifts are important because they are one of
the mechanisms which remove discharged substances from the diffuser area. The tidal
currents do not result in any net transport. Net drifts computed by the
hydrodynamic model TEA with a 10 cm boundary tilt (see A.3.6) are indicated at the
upper current meter stations in the spring (top plots) and lower current meter
station in the summer (bottom plots).

-------
STATION 1
,.—.‘
(I) -
a
o
3/2 3/9 3/16 3/23 3/30 4/6 4/13 4/20 4,’27 5/4 5,’ll 5/18 5/25
FIGURE A.c.1. NET DRIFTS OVER 10 TIDE CYCLES AT MWRA STATION 1

-------
C
(C-
r )
00
- ,-
________________ _______—j
I-
U)
-
0
u )
0
3/2 3/9 3/16 3/23 3/30 4/6
0
(C
p . .,
L
o0
L1 )
(N
STATION 2 UPPER
TE A NET DRIFT
4/13 4/20 4/27 5/4 5/11 5,’18 5/25
STATiON 2 UPPER
6’2 6/9 6’16 6,’23 6/30 7/7
7/14
7/21 7/28 8/4 8/11 8/18 8/25
FIGURE A.c.2. NET DRIFTS OVER 10 TIDE CYCLES AT MWRA STATION 2U
- 4 -J
‘4-
L
0
C)
-Q
I -
i -
E
0
L.
0
0

-------
E
o
%4

o
0
0
r’)
C)
-o
L
0
LL )
4 -
L
ci L

E
0
L
L 4-
o
TEA NET DRIFT
L wim - - - -
STATION 2 LOwER
FIGURE A.c.3. NET DRIFTS OVER 10 TIDE CYCLES AT MWRA STATION 2L
0
-o —
0
o-
STATION 2 LOWER
U,
C
T’ ’ ’ 1’’’’’
3/2 3/9 3/16 3,’23 3/30 4/6 4/13 4/20 4/27 5/4 5/11 5/18 5/25
I
6/2 6/9 6/16 6/23
6/30 7,’7 7,’l 4
7/21 7/28 84 8 /1 6/18 825

-------
0
1 )
E
I-
U L
4 J
4—
L
3/2 3/9 3, 16
3/23 3/30 4/6 4/13 4/20 4/27 5/4 5/11 5/18 5,’25
0
S T A T O 3 U° ER
- -TrT rn1rrrrrrT T ill rr?TT1 1 TT1 T TrTTTTI I I” TTTp T
6/2 6/9 6/16 6/23 6/30 7/7 7/14 7/21 7/28 8/4 8/11 8, /18 8,’25
FIGURE A.c.4. NET DRIFTS OVER 10 TIDE CYCLES AT MWRA STATION 3U
C)
-o
0
0
c
STATION 3 UPPER
TEA NET DRIFT
WITH 10CM NS TILT
0
LC)
I-
I-
0
L
I -
U)
E
U-)

-------
C
rl )
L
0 0 L
STATION 3 LOWER
0
3/2 3/9 3/16 3/23 3/30 4/6 4/13 4/20 4/27 5/4 5/11 5/18 5/25
C
(0
J
STATION 3 LOV\ER
6’2 6/9 6/16 6,’23 6/30 7/7 7/14 7/21 7’28 8 ‘4 8/11 8,’18 8/25
FIGURE A.c.5. NET DRIFTS OVER 10 TIDE CYCLES AT MWRA AT STATION 3L
L
C .—
(N
(.1)-
- LI)
E
0
0
C .—
I-
L
L I )L-
TEA NET DRIFT
WITH 10CM NS TILT
Q ) Ci
L
0
(N
U) -
iipr

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In
0
6/2 6/9 6/16 6/23 6/30 7/7
FIGURE A.c.6. NET DRIFTS OVER 10 TIDE CYCLES AT MWRA STATiON 4U
C)
L
0
(I )
E
0
S .TION 4 UPPER
7/14 7/21 7/28 8/4 8/11 8/18 8/25

-------
C
l,c —-
-o —
o
LC)
C
(N
L
FIGURE A.c.7. NET DRIFTS OVER 10 TIDE CYCLES AT MWRA STATION 4L
(I)

EL
I.
0
:
C
STAT O 4 LO\ ER
6,’2 6’9 6/16 6/23 6/30 7/7 7/14 7/21 7/28 e/4 8,’ll 8/18 8/25

-------
-c
L
b
U)
- t)
E
U
4— 0
L
0
L
it)
0
3/2 3/9 3/16 3/23 3/30 4/6 4/13 4/20 4/27 5/4 5/11 5/18 5/25
#J1 1
K 1 .J’
LJ
STATION 5 UPPER
L
U)
U) 4
E
U
9-
0
FIGURE A.c.8.
0
6/2 6/9 6/16 6/23 6/30 7/7 7/14 7,’21 7/28 8/4 8/11 8/18 8/25
NET DRIFTS OVER 10 TIDE CYCLES AT MWRA STATiON 5U
C ____
0
0
I :
STATION 5
TEA NET DRIFT
WI TH CM NS Ti LT —
0
‘ .0
L
Q)0
L
00
it)
b

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STATiON 5 LOWER
(I) L
- 4 - I
‘ — 0
6/2 6/9 6/16 6/23 6/30 7/7 7/14 7/21 7/26 8/4 8/11 8/18 8/25
FIGURE A.c.9. NET DRIFTS OVER 10 TIDE CYCLES AT MWRA STATiON 5L

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STATION 6 UPPER
l ! TJTTJ ! !IIII II, JII I II !I! I,IJIL .
6,/2 6’9 6/16 6/23 6/30 7/7 7/14 7/21 7/28 8/4 8/11 8/18 8/25
FIGURE A.c.1O NET DRIFTS OVER 10 TIDE CYCLES AT MWRA STATION 6U

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o _____________________________ _____
t STATION 6 LOWER
6/2 6/9 5/16 6/23 6/30 7/7 7/14 7/21 7/25 8/4 8/11 5/18 8/25
FIGURE A.c.11. NET DRIFTS OVER 10 TIDE CYCLES AT MWRA STATION 6L

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C)
0
(I )
E
0
9-
L
0
(N
0_
N
) L.
E
o
-4—’
‘4—
0
U)F-
L

3/2 3/9 3/16 3/23 3/30 4/6 4/13 4/20 4/27 5/4 5/11 5/18 5/25
C
‘ .0
I— ’
-o
00
U-,
(N
LT
C
6,’2 6/9 6,’16 6/23 6/30 7/7
FIGURE A.cJ2. NET DRIFTS OVER 10 TIDE CYCLES AT MWRA STATION 7U
0
pf)
0
STATION 7
TEA NET DRIFT
WITH 10CM NS TI
I-
L
STI flON 7 UPPER
7,/14 7,’21 7/28 8,’4 8 ,11 $,‘18 8,’25

-------
0
p,)
Q)0
-o
00
0
C’)
.-..- U,
E
C-)
‘ - 0
0
It)
-.J
6/2 6/9 6/16 6/23 6/30 7/7 7/14 7/21 7/28 8/4 8/11 8/18 8/25
FIGURE A.c.13. NET DRIFTS OVER 10 TIDE CYCLES AT MWRA STATION 7L
0

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J
STATION 9
C
P1 )
0
U )
c.
N
Cr,
E
0
4— C

L()
o
3/2 3/9 3/16 3/23 3/30 4/6 4/13 4/20 4/27 5/4 5/11 5/18
0
‘ .0—
0.

o
U-)
0
0 )
-o
a
U,
E
0
9-
a
FIGURE A.c.14. NET DRIFTS OVER 10 TIDE CYCLES AT MWRA STATION 9
0
I’)
0)
0
STATION 9
5/25
C) ‘-p-ri
I. ,
6/2 6/9 6/16 6/23 6/30 7/7 7/14 7/21 7/28
I,
8/4 8/11 8/18 8/25

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0
1 .0
Q)0
-0
L
00
(I )
a,
E
0
I .
4•- 0
L
0
3/2 3/9 3/16 3/23 3/30 4/6 4/13 4/20 4/27 5/4 5/11 5’18 5’25
6/2 6/9 6/16 6/23 6/30 7/7 7/14 7/21 7/28 8/4 6/11 6/18 6/25
FIGURE A.c.15. NET DRIFTS OVER 10 TIDE CYCLES AT MWRA STATION 10
0
STATION 10
0
TEA NET DRIFT
WITH 10 CM NS TILT
0 ______
1.0
I . . ,
()0
L
0
0
ST-flON 10
,—.‘ -
(I) -
)L
E
L)
- 0
L
0
U,
0

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ATFACHMENT A. d
LONGITUDINAL STRATIFICATION PROFILES

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Vertical profiles of seawater density measured by MWRA during 1987 along the
northern and southern transects (Figure A.2.ZI). Longitudinal stratification
profiles are lines of constant sea water density expressed in sigma-t units (density
in g/l minus 1000). These profiles demonstrate the onset of vertical density
stratification during the spring and its variability over the summer of 1987. The
pycnocline is the area where density lines are closely spaced.

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II 14 15 16 17 15 19 1 111 112 113 114
LOCATiON
SOURCE: MWRA STFP. VOL V. APP G, 1987
FIGURE A.d.1. CROSS-SECTION OF SEAWATER DENSITY ALONG NORTHERN TRANSECT
115
TI U 14 15 16 17 15 19 1 Ti) 112 T13 1)4 115
LOCATiON
(UNITS OF SIGMA-t)

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SOURCE: MWRA STFP. VOL V. APP G, 1987
FIGURE A.d.2. CROSS.SECTION OF SEAWATER DENSITY ALONG NORTHERN TRANSECT
Ti 12 73 74 15 16 17 ie 19 rn T1i T12 113 714
LOCATiON
715
Ti
12 13 14 75 16 17 16 19 710 711 112 113
LOCATION
714
(UNITS OF SIGMA-t)

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SOURCE: MWRA STFP, VOL V. APP G. 1987
FIGURE A.d.3.
CROSS-SECTION OF SEAWATER DENSITY ALONG NORTHERN TRANSECT
(UNITS OF SIGMA-t)
Ti T3 TI 15 16 17 15 19 T lii T12 T13 T14
LOCA ON
715
Ti T2 13 14 15 76 17 15 19 T1O Ti) T12 713 TM 115
LOCATION

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0
5
15
Si
S2
S3
0
5
$4
LOCATiON ø(AR Tt5)
$6
57
Si
S2
53
$4
Si
LOCATiON
SOURCE: MWRA STFP, VOL V, APP G, 1987
FIGURE A.d.4. CROSS-SECTION OF SEAWATER DENSITY ALONG SOUTHERN TRANSECT
(UNITS OF SIGMA-t)
$6

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Ti 13 13 74 15 16 17 . 19 T 711 T12 T13 TM
LOCAUON
SOURCE: MWRASTFP, VOL V, APP G, 1987
FIGURE A.d.5 CROSS•SECTION OF SEAWATER DENSITY ALONG NORTHERN TRANSECT
(UNITS OF SIGMA.t)
Ti 13 13 14 15 16 17 15 19 TiD 711 T?2 T13 TM 715
LOCATiON
115

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V
Si
AR SITE 6)
LOCATiON
SOURCE: MWRA STFP, VOL V. APP G, 1987
FIGURE A.d.6. CROSS-SECTION OF SEAWATER DENISTY ALONG NORTHERN TRANSECT
(UNITS OF SIGMA.t)
0
5
3D
35
Si
S2
53
0
5
S4
LOCATiON
$6
Si
15
4)
$2
53
$4
So
$7
O*AR SITE 6)

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ATTACHMENT A. e
CALIBRATED TEA TIDAL ELLIPSES COMPARED TO
MEASUREMENTS

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TEA predicted tidal ellipses for the semi-diurnal tide (M2) under unstratified and
stratified conditions are compared with M2 tidal ellipses developed from the
harmonic analysis of spring and summer, 1987 MWRA current meter data. The model
predictions are from the TEA calibration.

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U)
0
>
20.00
U)
0
>
FIGURE A.e.1. TIDAL ELLIPSE FROM MWRA MEASUREMENTS (MAR-MAY 87) AND
TEA CALIBRATION (NON-STRATIFIED CONDITIONING)
0
0
0
U (CM/S)
0
0
0
U (CM/S)

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0
q
0
(/)0
0
U
>
0
0
U,
METER
TEA
FIGURE A.e.2. TIDAL ELLIPSE FROM MWRA MEASUREMENTS (MAR-MAY 87) AND
TEA CALIBRATION (NON-STRATIFIED CONDITIONS)
E :-
TEA
—
0
0
•0
0
0
U)
U .
oLM . T .ER 5 vs NOçE 117
—10.00 0.00 10.00
U (CM/S)
0
0
It,
L
M ER
8 METER 7 vs NOPE 129
—10.00 0.00 10.00 20.00
U (CM/S)

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FIGURE A.e.3. TIDAL ELLIPSE FROM MWRA MEASUREMENTS (MAR-MAY 87) AND
TEA CALIBRATION (NON-STRATIFIED CONDITIONS)
METER
0
0
0
c. l
0
0
0
0
0_-
___________——- =: ------
TEA
0
0
METER 9 vs NOPE 367
0
0
0
0
0
—20.00
0.00
U (CM/S)
20.00
40.00
(1)0
%•% 0
0
>
8
0
c.,1
METER 10 vs N9DE 324
8
— o.oo
-40.00
0.00
U (CM/S )
40.00
80.00

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0
2
0
o
C
0
0
0
—10.00
20.00
U (CM/S)
FIGURE A.e.4. TIDAL ELLIPSE FROM MWRA MEASUREMENTS (AUG 87) AND
TEA CALIBRATION (STRATIFIED CONDITIONS, LOWER LAYER)
0
0
0
(I )
0
0
0
>
U (CM/S)
.—10.0o 0.00
10.00

-------
(I )
0
>
0
>
20.00
8
0
I -
U (CM/s)
U (CM/S)
20.00
FIGURE A.e.5. TIDAL ELLIPSE FROM MWRA MEASUREMENTS (AUG 87) AND
TEA CALIBRATION (STRATIFIED CONDITIONS, LOWER LAYER)

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ATTACHMENT A.f
SINGLE CONSTITUENT FARFIELD RESULTS

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High tide concentration contour plots calculated with the farfield model ELA are
given (nanograxns/liter) for conservative and decaying constituents, corresponding to
a base—case mass emission rate of’ 0.2 grains per second at the alternative discharge
sites. Results are for the last timestep of average net drift ELA runs, under
unstratified and stratified (lower layer) conditions. The average net drift results
correspond to steady state while the worst case net drift corresponds to the end of
a 10 day zero net drift period. Concentrations of individual constituents are
calculated using the base case results for the appropriate decay rate and
multiplying the concentrations by the ratio of the individual constituent mass
emission rate ot 0.2 grains per second.

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DISCHARGE SITE: 2
FIGURE A.f.1. HIGH TIDE CONCENTRATIONS (ngfl) FOR
BASE DISCHARGE LOADING (0.2 g/sec)
20 DAY HALF-LIFE CONSTITUENT
UNSTRATIFIED
AVERAGE NET DRIFT

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FIGURE A.f.2. HIGH TIDE CONCENTRATIONS (n f1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
DISCHARGE SITE:2
60 DAY HALF.LIFE CONSTITUENT
UNSTRATI FlED
AVERAGE NET DRIFT

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FIGURE A.f.3. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
DISCHARGE SITE: 2
CONSERVATIVE CONSTITUENT
UNST RATI F I ED
AVERAGE NET DRIFT

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FIGURE A.f.4. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
DISCHARGE SITE: 2
20 DAY HALF•LIFE CONSTITUENT
UNSTRATI Fl ED
WORSE CASE NET DRIFT

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DISCHARGE SITE: 2
FIGURE A.f.5. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
60 DAY HALF-LIFE CONSTITUENT
UNSTRATIFIED
AVERAGE NET DRIFT
40
20

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FIGURE A.f.6. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
DISCHARGE SITE: 2
CONSERVATIVE CONSTITUENT
UNSTRATIFIED
WORSE CASE NET DRIFT.

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DISCHARGE SITE: 2
20 DAY HALF•LIFE CONSTITUENT
STRATIFIED
AVERAGE NET DRIFT
FIGURE A.f.7. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)

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DISCHARGE SITE: 2
60 DAY HALF•LIFE CONSTITUENT
STRATIFIED
FiGURE A.f.8. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
AVERAGE NET DRIFT
1238

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FIGURE A.f.9. HIGH TIDE CONCENTRATIONS (ng/1)
DISCHARGE SITE: 2
CONSERVATIVE CONSTITUENT
STRATIFIED
AVERAGE NET DRIFT
FOR BASE DISCHARGE LOADING (0.2 g/sec)

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DISCHARGE SITE: 2
20 DAY HALF•LIFE CONSTITUENT
STRATIFIED
WORSE CASE NET DRIFT
FIGURE A.f.lO. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)

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DISCHARGE SITE:2
60 DAY HALF-LIFE CONSTITUENT
STRATIFIED
WORSE CASE NET DRIFT
2
FIGURE A.f.11. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)

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FIGURE A.f.12. HIGH TIDE CONCENTRATIONS (ng/l)
DISCHARGE SITE: 2
CONSERVATIVE CONSTITUENT
STRATIFIED
WORSE CASE NET DRIFT
160
80
FOR BASE DISCHARGE LOADING (0.2 g/sec)

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DISCHARGE SITE: 4
FIGURE A.f.13. HIGH TIDE CONCENTRATIONS (ng/l)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
60 DAY HALF•LIFE CONSTITUENT
UNSTRATIFIED
AVERAGE NET DRIFT

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DISCHARGE SITE: 4
FIGURE A.f.14. HiGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
60 DAY HALF .LIFE CONSTITUENT
UNSTRATI F l ED
AVERAGE NET DRIFT
9

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FIGURE A.f.15. HIGH TIDE CONCENTRATIONS (rig/i)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
DISCHARGE SITE: 4
CONSERVATIVE CONSTITUENT
UNSTRATI Ft ED
AVERAGENETDRIFT

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FIGURE A.f.16. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
DISCHARGE SITE: 4
20 DAY HALF•LIFE CONSTITUENT
UNSTRATIFIED
WORSE CASE NET DRIFT

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FIGURE A.f.17. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
DISCHARGE SITE: 4
CONSERVATIVE CONSTITUENT
UNSTRATIFIED
WORSE CASE NET DRIFT

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DISCHARGE SITE:4
20 DAY HALF-LIFE CONSTITUENT
STRATIFIED
AVERAGE NET DRIFT
FIGURE A.f.18. HIGH TiDE CONCENTRATIONS (ng/l)
FOR BASE DISCHARGE LOADING (0.2 g/sec)

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DISCHARGE SITE: 4
FIGURE A.f.19. HIGH TIDE CONCENTRATIONS (ngIl)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
60 DAY HALF.LIFE CONSTITUENT
STRATI F I ED
AVERAGE NET DRIFT
80

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FIGURE A.f.20. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/8ec)
DISCHARGE SITE :4
CONSERVATIVE CONSTITUENT
STRATIFIED
AVERAGE NET DRIFT

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DISCHARGE SITE :4
20 DAY HALF-LIFE CONSTITUENT
STRATIFIED
WORSE CASE NET DRIFT
FIGURE A.f.21. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 glsec)

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DISCHARGE SITE :4
60 DAY HALF.LIFE CONSTITUENT
STRATI F I ED
WORSE CASE NET DRIFT
FIGURE A.f.22. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
/

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DISCHARGE SITE :4
CONSERVATIVE CONSTITUENT
STRATIFIED
WORSE CASE NET DRIFT
4 \\
I
/
FIGURE A.f.23. HIGH TIDE CONCENTRATIONS (ngIl)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
\
7
-

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DISCHARGE SITE: 5
20 DAY HALF.LIFE CONSTITUENT
UNSTRATIFIED
AVERAGENETDRIFT
FIGURE A.f.24. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2. g/sec)

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DISCHARGE SITE: 5
60 DAY HALF-LIFE CONSTITUENT
UNSTRATIFIED
AVERAGE NET DRIFT
FIGURE A.f.25. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)

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FIGURE A.f.26. HIGH TIDE CONCENTRATIONS (ng/1)
DISCHARGE SITE :5
CONSERVATIVE CONSTITUENT
UNSTRATIFIED
AVERAGE NET DRIFT
1
FOR BASE DISCHARGE LOADING (0.2 g/sec)

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FIGURE A.f.27. HIGH TIDE CONCENTRATIONS (rig/i)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
DISCHARGE SITE:5
20 DAY HALF-LIFE CONSTITUENT
UNSTRATI F I ED
WORSE CASE NET DRIFT

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FIGURE Af.28. HIGH TIDE CO? CENTRAT1ONS (ng/1)
DISCHARGE SITE: 5
60 DAY HALF-LIFE CONSTITUENT
UNSTRATIFIED
WORSE CASE NET DRIFT
FOR BASE DISCHARGE LOADING (0.2 g/sec)

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FIGURE A.f.29. HIGH TIDE CONCENTRATION S(ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
DISCHARGE SITE:5
CONSERVATIVE CONSTITUENT
UNSTRATI FlED
WORSE CASE NET DRIFT

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DISCHARGE SITE: 5
20 DAY HALF-LIFE CONSITLJENT
STRATIFIED
AVERAGE NET DRIFT
FiGURE A.f.30. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
231
p

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DISCHARGE SITE: 5
F1GURE A.f.31. HIGH TIDE CONCENTRATIONS (rig/i)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
60 DAY HALF-LIFE CONSTITUENT
STRATIFIED
AVERAGE NET DRIFT
234

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DISCHARGE SITE: 5
CONSERVATIVE CONSTITUENT
STRATIFIED
AVERAGE NET DRIFT
FIGURE A.f.32. HIGH TIDE CONCENTRATIONS(ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)

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FIGURE A.f.33. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
DISCHARGE SITE: 5
20 DAY HALF•LIFE CONSTITUENT.
STRATIFIED
WORSE CASE NET DRIFT

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FIGURE A.f.34. HIGH TIDE CONCENTRATiONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
DISCHARGE SITE; 5
60 DAY HALF-LIFE CONSTITUENT
STRATIFIED
WORSE CASE NET DRIFT

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FIGURE A.f.35. HIGH TIDE CONCENTRATIONS (ng/1)
FOR BASE DISCHARGE LOADING (0.2 g/sec)
DISCHARGE SITE: 5
CONSERVATIVE CONSTITUENT
STRATIFIED
WORSE CASE NET DRIFT

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ATTACHMENT A. g
DISSOLVED OXYGEN FARFIELD RESULTS

-------
This attachment contains contour plots of predicted high tide dissolved oxygen (DO)
deficits (mg/l) under stratified (lower layer) and unstratified conditions. These
results are for worst case net drift conditions; they therefore represent DO
deficits which would occur after 10 days of zero net drift in Massachusetts Bay.
Results are given for both primary and secondary treated effluent discharge at the
alternative sites. Worst case dissolved oxygen concentrations corresponding to
these deficits are calculated by subtracting the predicted deficits from worst case
ambient dissolved oxygen concentrations measured in the field.

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DISCHARGE SITE: 2
PRIMARY TREATMENT
STRATIFIED
WORSE CASE NET DRIFT
0.05
N
FIGURE A.g.1. FARFIELD DISSOLVED OXYGEN DEFICIT (mg/I)

-------
DISCHARGE SITE: 4
PRIMARY TREATMENT
STRATIFIED
WORSE CASE NET DRIFT
0.05
N
2.25
FIGURE A.g.2. FARFIELD DISSOLVED OXYGEN DEFICIT (mg/I)

-------
DISCHARGE SITE: 5
\ PRIMARY TREATMENT
STRATIFIED
WORSE CASE NET DRIFT
0.05
FIGURE A.g.3. FARFIELD DISSOLVED OXYGEN DEFICIT (mg/i)

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DISCHARGE SITE: 2
SECONDARY TREATMENT
STRATIFIED
WORSE CASE NET DRIFT
0.05
N
1.0
0.5
FIGURE A.g.4. FARFIELD DISSOLVED OXYGEN DEFICIT (mg/I)

-------
DISCHARGE SITE: 4
SECONDARY TREATMENT
STRATIFIED
WORSE CASE NET DRIFT
0.2
FIGURE A.g.5. FARFIELD DISSOLVED OXYGEN DEFICIT (mg/i)

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0.05
N
DISCHARGE SITE: 5
SECONDARY TREATMENT
STRATIFIED
WORSE CASE NET DRIFT
0.1
FIGURE A.g.6. FARFIELD DISSOLVED OXYGEN DEFICIT (mg/I)

-------
DISCHARGE SITE: 2
PRIMARY TREATMENT
UNSTRATIFIED
WORSE CASE NET DRIFT
FIGURE A.g.7. FARFIELD DISSOLVED OXYGEN DEFICIT (mg/I)

-------
0.05
N
DISCHARGE SITE: 4
., PRIMARY TREATMENT
UNSTARTIF lED
WORSE CASE NET DRIFT
p
FIGURE A.g.8. FARFIELD DISSOLVED OXYGEN DEFICIT (mg/I)

-------
- DISCHARGE SITE: 5
. PRIMARY TREATMENT
UNSTRATIFIED
WORSE CASE NET DRIFT
p
FIGURE A.g.9. FARFIELD DISSOLVED OXYGEN DEFID DEFICIT (mg/I)

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DISCHARGE SITE: 2
PRIMARY TREATMENT
UNSTRATI Fl ED
WORSE CASE NET DRIFT
FIGURE A.g.1O. FARFIELD DISSOLVED OXYGEN DEFICIT (mg/I)

-------
DISCHARGE SITE: 4
PRIMARY TREATMENT
UNSTRATI FlED
WORSE CASE NET DRIFT
FIGURE A.g.11. FARFIELD DISSOLVED OXYGEN DEFICIT (mg/I)

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DISCHARGE SITE: 5
PRIMARY TREATMENT
UNSTARTIFIED
WORSE CASE N T DRIFT
0.05
FIGURE A.g.12. FARFIELD DISSOLVED OXYGEN DEFICIT (mg/I)

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ATTACHMENT A . h
FARFIELD SEDIMENT DEPOSITION RATES

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This attachment contains contour plots of predicted sediment deposition rates for
primary and secondary discharges at the alternative sites, under average net dr f:
for both unstratified and stratified (lower layer) conditions. Deposition rates
(g/m 2 /day) were calculated by summing prorated deposition rates computed for each of
three fall velocity effluent fractions.

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1.0
2.0
FIGURE A .h.1. SEDIMENTATION DEPOSITION RATES FOR PRIMARY DISCHARGE AT
SITE 2 IN NON-STRATIFIED CONDITION.

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FIGURE A.h.2. SEDIMENTATION DEPOSITION RATES FOR SECONDARY DISCHARGE AT
SITE 2 NON.STRATIFIED CONDITION.
0.8
Th 0.1

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FIGURE A.h.3. SEDIMENTATION DEPOSITION RATES FOR PRIMARY DISCHARGE AT
SITE 2 IN STRATIFIED CONDITION.
0.
1 2.6

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FIGURE A.h.4. SEDIMENTATION DEPOSITION RATES FOR SECONDARY DISCHARGE AT
SITE 2 IN STRATIFIED CONDITION.
0.1

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FIGURE A.h.5. SEDIMENTATION DEPOSITION RATES FOR PRIMARY DISCHARGE AT
SITE 4 IN NON-STRATIFIED CONDITION.

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FIGURE A-h.6. SEDIMENTATION DEPOSITION RATES FOR SECONDARY DISCHARGE AT
SITE 4 IN NON-STRATIFIED CONDITION.
0.5
p

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FIGURE A.h.7. SEDIMENTATION DEPOSITION RATES FOR PRIMARY DISCHARGE AT
SITE 4 IN STRATIFIED CONDITION.
0.1
•0

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FIGURE A-h.8. SEDIMENTATION DEPOSITiON RATES FOR SECONDARY DISCHARGE AT
SITE 4 IN STRATIFIED CONDITION.
0.
.50
p

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FIGURE A.h.9. SEDIMENTATiON DEPOSITION RATES FOR PRIMARY DISCHARGE AT
SITE 5 IN NON-STRATIFIED CONDITION.

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FIGURE A-h.lO. SEDIMENTATION DEPOSITION RATES FOR SECONDARY DISCHARGE AT
SITE 5 IN NON-STRATIFIED CONDITION.
0.32
0.15

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FIGURE A-h.11. SEDIMENTATION DEPOSITION RATES FOR PRIMARY DISCHARGE AT
SITE 5 IN STRATIFIED CONDITION.
p

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FIGURE A.h.12. SEDIMENTATION DEPOSITION RATES FOR SECONDARY DISCHARGE AT
SITE 5 IN STRATIFIED CONDITION.
0.2
p

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APPENDIX B
MARINE GEOLOGY AND SEDIMENT DEPOSITION

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APPENDIX B
MARINE GEOLOGY AND SEDIMENT DEPOSITION
B. 1 INTRODUCTION
Appendix F of this Draft SEIS presents several alternative outfall and diffuser
configurations. The alternatives involve the construction of an outfall tunnel from
Deer Island to one of three alternative diffuser sites (Sites 2, 11, and 5), where
discharge of treated wastewater will occur. Figure B.1.a shows the project region
and the alternative discharge sites under consideration. In this Appendix, existing
marine geology and bottom sediment conditions in the proposed discharge regions are
described, and impacts due to the proposed project are evaluated.
No field data collection program was conducted during the preparation of this Draft
SEIS; however, extensive data are available from previous investigations. The most
recent bottom sediment data were collected in conjunction with the Deer Island
Secondary Treatment Facilities Plan (STFP) (MWRA, STFP, V, 1987). These and other
data presented herein have been used to establish existing conditions.
The marine sediment changes evaluated in this Appendix are those associated with the
discharge and subsequent deposition of effluent particulate. Physical sediment
deposition rates and areas are presented, and alterations to existing bottom
sediment chemistry are estimated. The assessment of bottom chemistry impacts
includes consideration of background suspended solids settling, existing bottom
sediment composition, and bioturbatlon mixing of bottom sediments. The resultant
bottom sediment chemistry characteristics are presented for each alternative
discharge site. The methods used to predict these changes and the detailed results
of the predictions are presented in this Appendix, with a discussion of the results
and site comparisons made in Section 5.1.2 of this Draft SEIS. This information is
used in Section 5.1.3 of this Draft SEIS to assess impacts of the discharge on
marine biota.
B-i

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FIGURE B.1.a. ALTERNATIVE DISCHARGE SITES UNDER CONSIDERATION
B-2

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B.2 EXISTING CONDITIONS
The purpose of this section is to assess existing conditions in the vicinity of the
proposed diffuser sites. This assessment is based on available information on the
geology and bottom sediments in the Massachusetts Bay. This information is then
used as the basis for projecting sediment deposition impacts due to the proposed
discharge at each from the alternative diffuser sites. Projected sedimentation
impacts are presented later in this Appendix.
B.2.1 GEOLOGICAL SETI’ING
The geological setting presented herein is based on information from MWRA, STFP,
V,O,P,Q,R, (1987). The form of’ the inner shelf in the Massachusetts Bay area is an
irregular relict glaciated surface, comparable to the adjacent mainland. The
general form of this area includes numerous bedrock outcrops on the bottom separated
by channel or valley-fill deposits (Oldale et al., 1973). The fill material between
bedrock highs is often till, which can erode to a bouldery or “hard” bottom
(Meisburger, 1976). Glacial deposits in the area include several tills, stratified
outwashes, druznlins and glacial lake features (Cameron and Naylor, 1976). The most
recent deposit related to the last glaciation is the Boston “Blue Clay.” The
glacio-marine clays that are typical in coastal Maine (Presumpscot Formation) extend
as far south as the Boston region. These materials are commonly exposed on the
bottom of Massachusetts Bay and like the tills or outwashes, are exposed by marine
erosion or reworked to form part of the present surface sediments. Seismic
profiling has shown that the clay is widespread under Massachusetts and Cape Cod
Bays, and that many drumlins are entirely submerged and buried by these glacio-
marine clays (Kaye, 1976). Blue Clay was recovered in grab samples 7 nautical miles
east—northeast of Deer Island (vicinity of site 1 ). Mudballs, reminiscent of till
matrix material, were recovered during the same survey approximately 15 nautical
miles east-northeast of Deer Island.
The inner Massachusetts Bay region is at the edge of the Boston Basin, a structural
and topographic feature. Structurally, it consists of’ folded and faulted
sedimentary and volcanic rocks. There are several east-northeast trending folds
that project seaward from Boston Harbor, plunging at less than 20 degrees in the
B—3

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same direction. The bedrock is dominated by slightly metamorphosed argillite
(Cambridge Formation), which is commonly thinly bedded and fine grained. Many dikes
and sills of’ trap rock (basalt or diabase) intrude into the argillite in the Harbor
area. The bedrock surface is highly irregular in the area east-northeast of Deer
Island, varying from bottom outcrops to 250-foot (MSL) depths.
B.2.2 BOrrON SEDIf4ENT DISTRIBUTION
Numerous bottom samples in the Massachusetts Bay area have been collectedfor the
purpose of- developing a sediment distribution map of the area. These include MWRA,
STFP, V,R (1987), MDC (19814), Fitzgerald (1980), Schlee et al. (1973) and Willet
(1972). Fitzgerald indicated that broad areas of clean gravel cover much of’
Massachusetts Bay. Using photographs of sediment profiles, generalized bottom
sediment distribution maps have been produced (MWRA, STFP, V,P,Q 1987).
There is little consistency in the pictures of bottom conditions provided by these
maps. This is the result of extreme variability in bottom sediment types on several
scales. This conclusion was reached by Tetra-Tech (19814) in a technical review of
sediment data from the MDC in 19814. MWRA, STFP, V,N (1987) concluded that the area
consisted of’ “very patchy.. .benthic environments.” MWRA, STFP, V,R (1987) sampled
sediments at 15 sites on three separate cruises, taking three replicates at each
site. An analysis of variation between replicates and cruises showed that there is
often more variation in sediment types between replicates than over time or area.
Bottom types were described in MWRA, STFP, V,N and 0 (1987) and based on imaging
from a remotely operated vehicle. These transects are useful in that they describe
changing bottom conditions over a small area. There are major differences between
these visual descriptions and with grab samples from the same areas analyzed in
MWRA, STFP, V,R, 1987.
The available data indicate that bottom sediment types in the proposed discharge
region include silt, clay, mud, sand, gravel and rock. The variable nature of the
bottom is demonstrated by 1987 studies at potential outfall locations (Appendix C,
Figure C.1.b). The bottom sediment types can vary on a scale of tens of meters, and
it is difficult to generalize bottom characteristics from a limited array of data.
The available data do, however, define the types and ranges of sediments
encountered.
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B.2.3 DEPOSITIONAL TRENDS IN MASSACHUSETTS BAY
Several factors indicate that much of the bottom area in the region of interest can
be characterized as nondepositional. This includes areas where no deposition is
taking place, and areas where there is scour, or net removal of pre-existing bottom
sediments. These areas of nondeposition may include a veneer of underlying
sediments that have been reworked by recent marine processes. Most sample sets show
a dominance of gravel. Matrix material Is dominated by sands, with lesser amounts
of muds (MWRA, STFP, V,R, 1987). The numerous bedrock outcrops remain exposed.
Blue Clay and mudballs have been recovered near the surface. The bathymetry is
highly irregular, similar to the adjacent mainland.
MWRA, STFP, V,Q (1987) identified two “low kinetic” areas east of Nahant, based on
the presence of finer-grained sediments. The suggestion was made that these are
areas where deposition of suspended material may be taking place. However,
resampling the sites over a six-month period showed variability (i.e., coarser
material) at some of these stations. Therefore, the duration and extent of the
areas may be highly variable.
A seasonal deposition cycle has been hypothesized in the MWRA, STFP, V,P (1987),
where biogenically bound mud covering exposed rock surfaces in the summer was
observed, with the same surfaces free of mud in the winter. The death of tubicolous
species that bound the mud, as well as increased turbulence, was cited as
responsible for the loss of material. The same process was identified by Butman
(1978, 1987) through bottom photographs and turbidity measurements. It was shown
that the resuspension was a short—term, storm—related process in the winter
months. Butman’s data demonstrated that bottom velocities associated with winter
storms ranged from 5 cm/sec in Stellwagen Basin to 110 cm/sec in Inshore areas.
Butman’s data indicating that bottom scour is a wave-induced process (as opposed to
currents) are not necessarily consistent with MWRA’s suggestion (as presented above)
that accumulative “low kinetic” areas exist east of Nahant. The distribution of
wave energy (and bottom scour) would likely resuspend at least the upper sediments
in the area east of Nahant. However, the coastal embayments in the area (i.e.,
Boston Harbor and Lynn Harbor) are regions of extreme divergence of wave energy and
have reduced bottom scour.
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Available sea-bottom data in the area include that from Stone and Webster (1987) and
Weston Geophysical (1987). These reports show the irregular bedrock surface, with
irregular till surfaces superimposed on them. The topographic lows in this relict
relief were filled in by the glaciomarine (Blue) clays. These areas exist today as
fine sediments resulting from reworking or erosion of the topographic lava.
Therefore, even if the areas are nondepositional, fine material would be present.
B.2.1 SEDIMENTATION RATES
Existing sedimentation rates have been estimated in a number of past studies, which
have examined bottom sediments at various locations. The following discussion
presents estimates of sedimentation rates in Massachusetts Bay and Boston Harbor.
B.2. l.1 Massachusetts Bay
The broad areas of clean gravel which cover much of Massachusetts Bay suggested to
Fitzgerald (1980) that sediment accumulation has been negligible since glacial
times. The rise in sea level has transformed the shoreline over the present inner
shelf area. This has resulted in a reworking of glacial deposits, distributing a
“skin” of marine sand and gravel over much of the Massachusetts Bay area
(Fitzgerald, 1980). In the deeper water east of The Graves, Fitzgerald used the
thickness of marine sediments and an average submergence time of 10,000 years to
estimate that the average sedimentation rate was on the order of 0.006 cm/year.
This rate accounted for all material overlying the Blue Clay deposits.
Bothner (1987) estimated modern sedimentation rates in Massachusetts Bay at a site
7 nautical miles east of Deer Island (see Figure B.1.a). Both Pb-210 dates and
anthropogenic material located below the sediment surface were used to estimate a
modern accumulation rate of 0.2 to 0.6 cm/year.
This large range of accumulation rates in Massachusetts Bay requires that other
factors be taken into account:
B-6

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• Bioturbation of sediments creates a limitation in estimating sedimentation
rates from Pb-210 profiles (Fitzgerald, 1980). The effect of mixing of
sediments is to transport young sediments downward and old sediment upward,
making the apparent Pb-210 sedimentation rate too fast.
• Sediments can accumulate at a point through either “lateral” or “vertical”
deposition. The accumulation of muds by settling out of suspended solids
is vertical deposition. However, sands and coarser sediment are also
transferred or redistributed laterally along the bottom by currents. The
sediment distribution maps by MWRA, STFP, V,P and Q, 1987, identified up to
16 locations where ripples were observed on the bottom, even in this
limited sampling. MWRA, STFP, V,N and 0, 1987 also reported observing
ripples or ridges at most of the sandier bottoms. Bottom sediment ripples
are an indication of lateral movement of bottom materials. Therefore,
significant amounts of measured sediment accumulation may be due to lateral
redistribution rather than vertical sedimentation. Bothner (1987), during
his presentation, conceded that the sedimentation rates he estimated may be
influenced by sandwave migration.
Suspended sediments are introduced into the water column through erosion of the
nearshore bottom (as evidenced by lag deposits), bluff retreat associated with
shoreline erosion riverine input, runoff and arithropogenic input. The larger
topographic basins in deeper water, such as Steliwagen Basin, are dominated by
relatively smooth surfaces and fine sediments (Schlee et al., 1973; SAIC, 1987).
These are likely areas for deposition of suspended sediments. Tucholke and
Hollister (1973; in Butman, 1978) suggested that most of this deposition occurred
just after the glacial retreat, and that the sedimentation rate has steadily
decreased since then, with the current deposition rate in Stellwagen Basin estimated
to be 0.001 to 0.002 cm/year.
B.2. 1 1.2 Boston Harbor
The harbors along the central Massachusetts coast are protected areas where
suspended sediments may accumulate. In addition to the various processes associated
with estuarine sedimentation in these areas, wave refraction studies have shown that
the entrances of Boston Harbor and Lynn Harbor are areas of extreme divergence of’
wave energy. Therefore, they are areas where the accumulation of’ sediments may
occur. As well, erosion of’ unimproved Boston Harbor Island shorelines and inflowing
rivers are sources of sediments to the system. Also, the east—west tidal
circulation patterns on the adjacent shelf tend to carry some suspended material
into the Harbor.
B-7

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Using the thickness of sediments inside Boston Harbor, Fitzgerald (1980) estimated
sedimentation rates to be 0.0114 and 0.016 cm/year, which probably represent a
minimum Holocene sedimentation rate in the Harbor. A maximum rate was estimated to
be 0.1 cm/year. This was based on an assumed 10,000 year period of deposition.
Pb—210 sedimentation rates were calculated by Fitzgerald (1980) at the entrance to
Boston Inner Harbor (0.27 cm/year) and at the Inner Harbor in the vicinity of
Fort Point Channel (0.14 cm/year). This approach can be compared to a U.S. Army
Corps of Engineers estimate of accumulation of 0.2 cm/year based on the volume of
material collected between successive dredging operations in the Inner Harbor
(Fitzgerald, 1980). Fitzgerald (1980) concluded that modern sedimentation rates
were 0.2 to 0.3 cm/year in Boston Harbor.
Bothner (1987) presented data on sedimentation rates in Boston Harbor. Using Pb-210
methods, one site in the Harbor showed a modern accumulation rate of 2 cm/year.
Studies of sedimentation in the inner harbor (Rosen, in progress) show long—term
sedimentation rates of 0.1 cm/year over the past 5,500 years, based on thickness of
the estuarine sequence and carbon dates of the deposit.
B.2.k.3 S”nvn ry of Deposition Rates
Available information on depositional trends indicates that much of the proposed
discharge region does not have long-term sustained deposition of suspended solids.
However, periods of water column suspended solids deposition do occur in most areas,
even though they may be interrupted by periods of resuspension. The rate at which
background sedimentation occurs is important in assessing the impact of deposition
of effluent particulate.
Available data indicate a wide variation in background sedimentation rates, although
there is a general trend of higher sedimentation in Boston Harbor and lower
sedimentation in deeper offshore basins (Table B.2.a). In the area of the proposed
discharge sites, the available data indicate deposition rates of 0.2 to 0.6 cm/yr
(Bothner) and 0.006 cm/yr (Fitzgerald). As discussed previously, this is a wide
range of values, and it is possible that the higher rates are artificially high due
to factors such as Pb-210 methods and lateral deposition. For this Draft SEIS, a
B-8

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background sedimentation rate of 0.05 cm/yr was used.
one order of magnitude above and below the lowest
respectively. A rate higher than that reported for
0.002 cm/yr) is appropriate because the area is closer
higher surface water production. MWRA used a higher
analyses (MWRA, STFP, V,C, 1987). The lower rate
(0.05 cin/yr) is more conservative (i.e., provides
compounds of sewage origin).
This value is approximately
and highest measurements,
Steliwagen Basin (0.001 to
to land erosional sources and
rate of 0.1 cm/yr for their
used in this Draft SEIS
minimal dilution to toxic
TABLE B .2. a. SUMMARY OF REPORTED MASSACHUSETTS BAY MD BOSTON HARBOR
SEDIMENTATION RATES
Rate
Location
Est. Method
Source
(cm/yr)
Boston Harbor
Sediment Thickness
Fitzgerald, 1980
o.0i’i- O.i
Boston Harbor
Pb-210
Fitzgerald, 1980
0.12-0.50
Boston Harbor
Dredging
Fitzgerald, 1980
0.2
Boston Harbor
Pb-210
Bothner 1987
2.0
Boston Harbor
Carbon dates
Rosen, in progress
1.0
Mass Bay
10,000 yr cores
Fitzgerald, 1980
0.006
Mass Bay
Pb-210 and Artifact
Bothner, 1987
0.2-0.6
Stellwagen Basin
Various
Tucholke and Hollister,
1973
0.001-0.002
Mass Bay
—
MWRA, STFP, V,C 1987
0.1
Mass Bay
Lit. Rev.
This Draft SEIS
0.05
B.2.5 SEDIMENT CHEMISTRY
The contaminants for which effluent deposition impacts will be assessed are
summarized in Table B.2.b. This list is based on the effluent contaminant screening
process used by MWRA (MWRA, STFP, V,A 1987). Further information on the development
of this list is presented in Appendix C of this Draft SEIS. Although the pesticides
14,14 -DDT and dieldrin were screened-out of the environmental impact assessment due to
low effluent concentrations, they have been retained in this sedimentation analysis
for use in assessing public health impacts (Draft SEIS, Chapter 5). PAHs were
screened due to relatively low total effluent concentrations and particle
association values. Several data sources have been used to develop estimates of
background concentrations of these compounds in the existing bottom sediments. As
part of’ the MWRA STFP, bottom sediment samples were collected in Massachusetts Bay
B-9

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in April, June and August, 1987 (MWRA, STFP, V,S, 1987). On each date, three
replicate samples were collected at three stations along each of the potential
diffuser transects. The stations sampled are shown in Figure B.2.a. Sediment
sample analysis included polychiorinated biphenyi.s (PCBs) and metals (arsenic,
copper, mercury, nickel, and zinc). These data have been used to define existing
conditions for several of the contaminants listed in Table B.2.b. For the other
contaminants, MDC waiver data were used (MDC, 19811). The background concentrations
developed are presented in the following sections. The sites assessed are Site 2
(sediment transect A in STFP V,S), Site 11 (sediment transect C in STFP V,S) and
Site 1.5 (sediment transect D in STFP V,S), which is used to represent soft bottom
conditions at Site 5. Since no soft bottom sampling was successful at Site 5, this
was the best approximation.
TABLE B.2.b. CONTAMINANTS FOR ASSESSMENT OF SEDIMENT DEPOSITION IMPACTS
Existing Sediments
Data Source
Compound
Class I Sediment
Threshold
(ppm)*
MWRA,
STFP,
V,S,
1987
PCB Compounds (total)
0.5
Metals
MWRA,
MWRA,
MWRA,
MWRA,
MDC,
MDC,
MWRA,
STFP,
STFP,
STFP,
STFP,
19814
19814
STFP,
V,S,
V,S,
V,S,
V,S,
V,S,
1987
1987
1987
1987
1987
Arsenic
Copper
Mercury
Nickel
Selenium
Silver
Zinc
10
200
0.5
50
--
--
200
Pesticides
MDC,
MDC,
MDC,
MDC,
19814
19814
19814
19811
Aldrin
11,11 DDT
Dieldrin
Heptachlor
—-
—-
—-
—-
Acid, Base Neutrals
**
**
**
Butylbenzy]. phthalate
Di-n-ootyl phthalate
Bis(2—ethylhexyl)phthalate
—-
--
——
* Massachusetts DEQE-DWPC classification (Barr, 1987).
** No available data for existing bottom sediments.
B-iD

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NAUTICAL MILES
TRANSECT C
TRANSECT A SITE 4
• ,-., SITE5
SITE2 •
•
• €PDâ •
€
MASSACHUSETTS BA Y
.4 .
LEGEND
1982 MDC WAIVER STATION
SEIS ALTERNATIVE SITES
SOURCE: ADAPTED FROM MWRA STFP, VS. 1987
AND MDC WAIVER VOL. 1, 1984
FIGURE B.2.a. GENERAL STATION LOCATIONS FOR SEDIMENT SAMPLING
B-il

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B.2.5.1 PCB Compounds
PCB analyses were calculated by MWRA (STFP, V,S, 1987) on the basis of Aroclor
12511. When the results did not match a standard Aroclor 12514, results were reported
for the Aroclor that gave the best match. Total PCB results are the sum of the
individual Aroclors identified in ppm dry weight (MWRA, STFP, V,S, 1987). A summary
of’ the range and average of the PCB measurements is presented in Table B.2.c. In
general, there was little variation in PCB concentration between transects and
between stations, with the highest measurements on all three transects occurring on
the same sampling date. For the purpose of assessing potential discharge impacts,
the average PCB concentration for each transect was used to represent background
conditions at the associated alternative discharge sites. PCB concentrations are
below the threshold for a Class I sediment using Massachusetts Division of Water
Pollution Control (DWPC) dredged materials classification (Table B.2.b). Class I
sediments have the lowest chemical concentration and have minimal dredged material
disposal restrictions. This comparison to dredging standards is presented for site
comparison purposes only.
TABLE B.2. c. SUMMARY OF SEDIMENT PCB MEASUREMENTS
Total PCB Concentration (ppm dry weight)
- Average
Range
Transect A (Site
2)
0.001—0.033
0.012
Transect C (Site
L I)
<0.001 _0.0 142
0.018
Transect D (Site
14.5)
<0.001 _0.01 17
0.011
B.2.5.2 Metals
Concentrations of trace metals are presented in Table B.2.d as ranges and averages
in ppm dry weight. Averages were calculated for three replicates at each of the
three stations at transects A (Site 2), C (Site I I), and D (Site 14.5) over three
cruises.
In general, the highest concentrations for all metals occurs at transect C
(Site LI). Since selenium and silver were not analyzed by the MWRA, previous data
from 1979 and 1982 (MDC Waiver, 19814) were used to provide estimated background
B- 12

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concentrations. Metals concentrations in the vicinity of the proposed discharge
sites were only available at two stations, 9 and PD, near transects 2 and 4.5,
respectively (Table B.2.d and Figure B.2.a.).
The data presented in Table B.2.d was used to represent background conditions at the
alternative discharge sites. For selenium and silver, the measurement at MDC
station PD was used for all potential discharge sites. All metals tested fall below
the DWPC Class I threshold for dredged materials (Table B.2.b), and are therefore
relatively clean by this standard.
TABLE B.2 . d. SUMMARY OF SEDIMENT METALS MEASUREMENTS
Metal Concentrations (ppm dry weight)
Range Average
Transect A (Site 2)
Arsenic 0. 1 11 3.89 2.87
Copper 1.73 63.28 12.56
Mercury 0.020 0.38 0.15
Nickel 1.87 7.88 11.66
Selenium NA NA
Silver 21 10 (b)
Zinc 9.7 — 47.32 26.12
Transect C (Site 4)
Arsenic 11.30 - 6.76 5.53
Copper 9.15 - 1414.62 17.88
Mercury 0.036 - 0. 1 1 14 0.17
Nickel 5.27 - 13.97 9.24
Selenium NA NA
Silver NA NA
Zinc 30.03 — 152.51 147.55
Transect D (Site 14.5)
Arsenic 3.17 7.24 4.62
Copper 1.09 16.84 6.71
Mercury 0.19 1.04 0.11
Nickel 2.30 8.85 4.88,
Selenium
Silver < 010 (c)
Zinc 11.145 107.60 25.03
(a) MWRA, STFP, VS, 1987, unless otherwise noted.
(b) 1979 MDC Waiver Data, Station 9 (MDC Waiver, 19811).
(c) 1982 MDC Waiver Data, Station PD (MDC Waiver, 19814).
(d) NA - not analyzed.
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B.2.5.3 Pesticides
The pesticides aldrin, 4,4-DDT, dieldrin and heptachior were not analyzed by the
MWRA. However, pesticide samples were collected at Station PD in 1982 (MDC Waiver,
1984). Additional pesticide samples were collected in 1984, however, no sampling
stations were located in the proposed discharge region (MDC Waiver, 1984). For the
1982 data, no pesticides were detected using a detection limit of 0.040 ppm.
Therefore, for the Draft SEIS analysis, background bottom sediment concentrations of
0.040 ppm were used for aldrin, LI, I -DDT, dieldrin and heptachlor.
B.2.5. 1 1 Acid Base Neutrals
Bis (2-ethylhexyl) phthalate, butylbenzyl phthalate and di-n-octyl phthalate were
not measured by the MWRA (STFP, V, 1987) or the MDC Waiver. Since no background
bottom sediment data are available, the effect of bioturbation mixing of effluent
particulate cannot be fully evaluated. For the Draft SEIS, a background
concentration of zero in the existing sediments was used to assess bioturbation
mixing effects, to make relative comparisons among sites. The actual bottom
Sediment concentration after mixing will be higher if these acid base neutral
compounds are present in the existing bottom sediments.
B.2.5.5 Bioturbation Mixing Depth
One of the processes which influences the impact of suspended solids deposition is
the mixing of bottom sediments by benthic organisms, known as bioturbation. Benthic
organisms mix the sediments both by burrowing and feeding. Some animals feed head
down and thus deposit deeper sediments at the surface, while others feed at the
surface and deposit materials at depth. By this process the effluent particulates
are incorporated and dispersed into the existing bottom sediments. Based on the
above data, the existing bottom sediments are of lower contaminant concentration
than the effluent particulate. Therefore, the deeper the influence of benthic
mixing, the more the effluent particulate contaminants are diluted. REMOTS sediment
profiling was conducted in Massachusetts Bay to measure the apparent redox potential
discontinuity depth, or the depth to which the fine grained bottom sediments are
oxidized (MWRA, STFP, V,P and Q, 1987). This depth can be interpreted as a
conservative indicator of biological mixing depth. In general, this depth varied
B- 14

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from 2 to 11 cm, with occasional deeper measurements and frequent zero measurements
due to rocky bottom. This range is consistent with measured values in similar
temperate marine systems (Maughan, 1986; Doering et al., 1986; Doering and Oviatt,
1986). For the purpose of assessing the impact of biological bottom mixing on the
concentration of settled effluent particulates, a bioturbation mixing depth of 3 cm
will be considered. This value is reasonable for organically enriched areas and
generally conservative for Massachusetts Bay, based on the available data.
As an alternative, more conservative case, the impact of a zero mixing depth is also
assessed. This situation might occur in a rocky bottom area where there is minimal
soft bottom sediment but where periods of deposition may occur between resuspension
events.
B.3 SEDIMENT QUALITY IMPACTS
B.3.1 INTRODUCTION
A simulation of the composition of bottom sediments in Massachusetts Bay was
conducted to measure the changes that will take place in the intervals of 6 months,
1 year and 5 years following initiation of primary effluent discharge at the
alternative outfall locations. Outfall sites considered are Sites 2, i4, and 5.
Constituents potentially producing adverse effects on marine organisms or public
health due to primary discharge were also evaluated for a secondary discharge.
Constituents of primary effluent found to produce no adverse effects were assumed to
cause no adverse effects from secondary effluent discharge.
Over the time intervals mentioned, three primary factors were considered:
sedimentation of the primary effluent, ambient water column sedimentation, and
bioturbation of the existing bottom sediments. The model assumes that annual
deposits are fully bioturbated, and resuspended sediments are redeposited, and
therefore, there is no net impact due to resuspension. An additional case for
seasonal deposition on rock surfaces is presented. To make the predictions no decay
of the constituents is applied.
B-15

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B.3.2 EFFLUENT PARTICULATE DEPOSITION RATES
As part of this Draft SEIS, the deposition of effluent suspended solids from
effluent was evaluated using the models TEA-NL and ELA. The sediment accumulation
rates and areal distributions presented in Appendix A of this Draft SEIS were used
as the basis for assessing changes in bottom sediment composition due to the
proposed discharge. Both stratified and nonstratified conditions were assessed.
The mass/area/day units are converted to thickness of sediment on the bottom per
year (mm/year) with the assumptions described in the following paragraph.
It is assumed that the effluent will be 80 percent organic and 20 percent inorganic
(U.S. EPA, 1982), and an average density has been calculated using weighted means.
An organic density of 1.06 g/cm 3 was used to represent the organic fraction in place
on the sea floor after deposition. This is consistent with the density used by MWRA
(STFP, V,C, 1987) for converting background deposition in mm/day to mass deposition
rates. An inorganic density of 2.65 g/cm 3 is based on the density of quartz and the
average density of the common clay minerals. Fitzgerald (1980) confirmed that
quartz is dominant constituent of the muds in Boston Harbor. The weighted mean
density of the effluent particulates was calculated to be 1.14 g/cm 3 .
B.3.3 SEDIMENT CHEMISTRY PREDICTION METHODS
To assess impacts on bottom sediment chemistry three principal processes have been
considered: deposition of chemicals associated with effluent particulate;
deposition of chemicals associated with background suspended solids settling; and
mixing of deposited sediment chemicals with existing bottom sediments
(bioturbation).
B.3.3.1 Effluent Particulate Chemical Deposition
The chemical composition of effluent suspended solids was assessed by MWRA (STFP V
A, 1987) and MDC (19814). These values were independently checked as part of this
Draft SEIS. It was concluded that, with the exception of butylbenzyl phthalate and
PCB the chemical concentrations in effluent suspended solids estimated by MWRA were
reasonable for the contaminants being assessed herein. For butylbenzyl phthalate
the reported concentration of 8.5 ppm (MWRA, STFP, V,A, 1987) should actually be
B- 16

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85 ppm (Koib, B., 1988). As described in Appendix A, an influent PCB concentration
of 0.005 mg/i was used in this Draft EIS rather than the concentration of 0.001 mg/i
used by MWRA.
B.3.3.2 Background Particulate Chemical Deposition
Two sources of data were synthesized to estimate this parameter: the analyses of
particulate matter in the water column and an estimated sedimentation rate. As
discussed in Section B.2.L , an average background suspended solids deposition rate
of 0.5 mm/yr was used in this analysis. The chemical concentrations associated with
the background suspended solids were assessed from the available water column
measurements presented in the STFP (MWRA, STFP V,M, 1987). An average water column
total suspended solids concentration of 2.17 mg/i was used to represent background
suspended solids.
Background water column data is presented in the STFP for particulate and dissolved
concentrations of several chemicals at several depths and sites (MWRA, STFP, V,M,
1987). The average of particulate concentration for each chemical is used to
calculate the rate of deposition of each chemical. These data are summarized in
Tables B.3.b, c and d at the end of this Appendix. There were no water column
particulate measurements available for the pesticides. For this investigation,
measured levels of pesticides on background bottom sediment particles were used as
an approximation of water column particulate concentrations. The concentration of
each chemical in the background water column suspended solids (mass chemical/mass
suspended solids) was estimated using these data.
B.3.3.3 Bioturbation and Resuspension of Bottom Sediments
In order to simulate bottom sediment conditions, it was assumed that all bottom
sediments were bioturbated on an annual basis. Bioturbation was assumed to be
complete over a given thickness of bottom sediment, thus any annual accumulation
would be totally mixed each year. As was discussed previously in Section B.2.5.5, a
bioturbation mixing depth of 3 cm was used in this assessment.
The concentration of chemicals in existing bottom sediments were discussed
previously in Section B.2.5. These existing bottom sediment concentrations were
B- 17

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used in the simulation of bioturbation mixing for the primary discharge. When
sediment concentrations were simulated for secondary effluent discharge, the
previous 5 years of primary discharge were taken into consideration. This was done
separately for each site, by taking the predicted concentrations after 5 years of
non-stratified primary discharge and calculating a weighted mean concentration. The
weighted mean was then used for the potentially affected area. Based on the
observed resuspension and sediment transport (as described above in this Appendix),
it was assumed that during the 5 years there would be a redistribution and
equalization of the deposited material. Thus a weighted mean was judged to be the
best representation of sediment conditions after 5 years of primary discharge.
B.3. 1 1 SIMULATION OF SEDIMENT IMPACTS
Simulations assuming nonstratified conditions were done to represent Sites 2, II, and
5; primary and secondary effluent; periods of 6 months, 1 year and 5 years. In
addition, predictions of sediment concentrations were made for stratified conditions
for each 6-month case. In the 6 month simulation at Site 5, an additional
simulation was performed to represent the concentrations of sediment accumulating on
rocky surfaces during stratified conditions. As described above in Section B.2
there is extensive rocky substrate in the immediate vicinity of Site 5. During the
summer an extensive attached benthic community becomes established on the rocks.
This community can establish a mat of biologically bound material which would
include discharge effluent particles If they were present in the water column. This
material accumulates in the summer, is resuspended in the winter, and is not
influenced by existing bottom sediments. This same phenomena would occur in rocky
substrate at other discharge sites. The calculation is done for Site 5 because the
diffuser site has more rocky substrate. The results of the simulations for
representative constituents which are of ecological or public health concerns (see
Chapter 5) are summarized in Table B.3.a at the end of this Appendix. In addition,
examples of full results for all sites for a range of conditions (5-year
nonstratified secondary, 5-year nonstratified primary, and 6 months stratified
primary) are presented in Tables B.3.b, c and d at the end of this Appendix. These
tables also present the constituent concentrations for background sediments and
effluent particles.
B- 18

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The simulation process takes a weighted average of the concentration of a particular
chemical on the effluent solids and in the background suspended solids. The two
concentrations are weighted by the respective fraction of the effluent deposition
rate and the background deposition rate. To account for bioturbation mixing this
combined concentration is further averaged with the chemical concentration in the
background bottom sediments. This average is weighted by the respective fraction of
the total deposition depth over the specified time period (6 months, 1 yr or 5 yrs)
and the depth of bioturbation mixing. This simulation process is summarized by the
following equations:
( CX ) (DEPe) + (CXb) (DEPb )
CXavg e DEPe + DEPb
where CXavg = average concentration of chemical X in deposited sediments
(ug/g)
CXe concentration of chemical X in effluent suspended solids
(ug/g)
DEPe = effluent suspended solids deposition rates (mm/yr)
CXb = concentration of chemical X in background water column
suspended solids (ug/g)
DEPb background suspended solids deposition rates (mm/yr)
CX - ( CXavg)(DEPe+ DEPb)(T)+ (CXbot)(D )
m (DEP + DEPb)(T) + D
where CXm average concentration of’ chemical X in bottom sediments
after bioturbation mixing (ug/g)
time period of interest (0.5 yr, 1 yr or 5 yr)
CXbot concentration of’ chemical X in existing bottom sediments
(ug/g)
depth of bioturbation mixing (mm)
In addition, a weighted mean effluent sedimentation rate over the entire area of
deposition was calculated for each site for total deposition to allow for overall
comparison. This was done by averaging each deposition rate contour weighted by the
extent of’ the area within the contour.
B- 19

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B.3.5 SUMMARY OF PREDICTED SEDIMENT CONCENTRATIONS
For nearly all compounds, the highest simulated concentrations occur at Site 2 and
the lowest concentrations at Site 5 (Table B.3.a, at the end of this Appendix). For
several metals, the highest background bottom sediment concentrations occur at
Site 1 , and therefore, in some cases, high simulated concentrations also occur at
Site l .
The worst case simulation is the case of primary effluent with no bioturbation for
si-x months duration. In this case, it is assumed that effluent and background water
column solids are deposited on a rocky bottom with no dilution with existing bottom
sediments. This case could occur at any location where sediment resuspension has
exposed a rocky bottom substrate. ROV studies (MWRA STFP, V,O, 1987) indicate that
rocky substrate is more prevalent in the immediate vicinity site 5, that site L , and
minimal at site 2. Therefore, the analysis was done only for site 5. These
concentrations would only occur in the limited portion of the deposit area where
horizontal hard rock surfaces occur.
B-20

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Table B.3.a Summary of Site To Site Comparison of Sediment Concentration
PRIMARY SECONDARY
SITE 2SITE 4SITE 5 5HB :SITE 2SITE 4SITE 5 5 HB
PCB BACKGROUND 0.01 0.02 0.01 0.01 : 0.10 0.10 0.11 0
0.5 IRS STRAT
MAX CONCEN 0.41 0.22 0.15 5.57 : 0.17 0.14 0.13 1.86
I **>o.1ug/g 3.54 2.42 1.35 50.15 :16.95 9.8 7.5 >7.5
5 IRS UNSTRAT
MAX CONCEN 1.38 1.03 0.77 : 0.33 0.27 0.21
KM**>0.lug/g 17.67 7.8 10.43 : 6.23 5.19 4.49
S
BEHP BACKGROUND NA NA NA : 1.08 1.06 1.21 0
0.5 YRS STRAT
MAX CONCEN 5.95 3.05 2.05 81.77 : 2.1 1.57 1.46 25.07
KM**>7.2ug/g 0 0 0 35.56 : 0 0 0 5.7
5 IRS UNSTRAT
MAX CONCEN 20.21 14.89 11.02 : 4.28 3.34 2.54 0
KM**>7.2ug/g 2.78 2.42 1.61 : 0 0 0
DDT BACKGROUND 0.04 0.04 0.04 : 0.05 0.05 0.05 0
0.5 IRS STRAT
MAX CONCEN 0.07 0.05 0.05 0.43 • 0.05 0.5 0.5 0.16
**>0.07ug/g 0 0 0 50.15 : 0 0 0 7.5
5 IRS UNSTRAT
MAX CONCEN 0.14 0.11 0.09 : 0.06 0.06 0.05 0
**>0.1ug/g 1.36 0.94 0 : 0 0 0
S
S
ZN BACKGROUND 26.12 47.55 25.03 : 42.5 61.84 43.06 0
0.5 IRS STRAT :
MAX CONCEN 101 86 51 1068 :61.50 70.05 46.64 370
**>7O9ug/g 0 0 0 3.44 : 0 0 0 0
5 IRS UNSTRAT
MAX CONCEN 283 234 167 :85.13 91.10 62.40
KM**>709ug/g 0 0 0 : 0 0 0
Notes: HB= Hard Bottom area; the entire area indicated would not
be at the concentration but only hard rock sufaces within the
area
For PCB at Site 5, for secondary effluent, the predicted depositions
in Table b.3.e are somewhat higher than for Site 4. This is an
artifact of the prediction method because a much smaller area
was used at Site 5 to estimated weighted average after 5 years
of primary. Since the rates are actually smaller at site 5 than at
site 4 the site 4 rates have been used in this calculation.
B-2 1

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Table B.3.b. Effluent Sedimentation at Site 2 Under Secondary
Treatment and Non—stratified Conditions Over 5 Years
Depos. Area Dis. Area Sed Rate Weighting
g/m2/day Km2 Km2 mm/yr factor
0.1 7.590 3.833 0.026 0.013
0.2 3.757 0.761 0.052 0.005
0.25 2.996 0.457 0.065 0.004
0.3 2.539 0.852 0.078 0.009
0.4 1.687 0.578 0.104 0.008
0.5 1.109 0.565 0.130 0.010
0.6 0.544 0.381 0.156 0.008
0.7 0.163 0.163 0.182 0.004
B-22

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Table B.3.b. (Continued) Input Concentrations to Predict Bottom Sediment
Concentrations at Site 2 Under Secondary Treatment and Non-stratified
Conditions Over 5 Years for Selected Compounds
Background I Effluent I Bottom
Sedimentation I Constituents Seds.
I I
Water Solids Total Primary Secondary
Conc. Conc. Depos. Conc. Conc. Conc.
ugh ug/g ug/m2/day ug/g ug/g ug/g
4,4—DDT 0.045 0.124 0.61 0.15 0.0451
PCB 0.0005 0.230 0.631 8.13 2.26 0.1017
BEHP* 0.000 0.000 121.00 16.00 1.0849
Zinc 0.1335 61.519 168.563 1552.00 1198.00 42.4979
* = Complete data set not available. Background concentrations assumed to be zero.
3
Table B.3.b. (Continued) Projected Bottom Sediment Concentrations (ug/g) at Site 2 Under
Secondary Treatment and Non-stratified Conditions Over 5 Years
for Selected Compounds
Effl Depo: 0.1 0.2 0.25 0.3 0.4 0.5 0.6 0.7
(g/1n2/day)
Btm Area km2 3.833 0.761 0.457 0.852 0.578 0.565 0.381 0.163
4,4—DDT 0.04737 0.04960 0.05072 0.05182 0.05403 0.05621 0.05838 0.06053
PCB 0.14362 0.17539 0.19118 0.20690 0.23817 0.26919 0.29996 0.33050
BEHP* 1.48064 1.95602 2.19230 2.42764 2.89554 3.35976 3.82035 4.27734
Zinc 49.98326 55.95752 58.92686 61.88444 67.76458 73.59850 79.38674 85.12982
* = Complete data set not available. Background concentrations assumed to be zero.

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Table B.3.b. (Continued) Effluent Sedinientation at Site 4 Under Secondar
Treatment and Non—stratified Conditions Over 5 Years
Depos. Area Die. Area Sed Rate Weighting
g/ m 2/day K m 2 Km2 mm/yr factor
0.1 5.58 3.13 0.026 0.015
0.2 2.45 0.55 0.052 0.005
0.25 1.90 0.62 0.065 0.007
0.3 I28 0.81 0.078 0.011
0.4 0.47 0.462 0.104 0.009
0.5 0.01 0.008 0.130 0.000
B-21 1

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Table B.3.b. (Continued) Input Concentrations to Predict Bottom Sediment
Concentrations at Site 4 Under Secondary Treatment and Non-stratified
Conditions Over 5 Years for Selected Compounds
Background I Effluent I Bottom
Sedimentation I Constituents I Seds.
I I
Water Solids Total Primary Secondary
Conc. Conc. Depos. Conc. Conc. Conc.
ugh ug/g ug/m2/day ug/g ug/g ug/g
4,4—DDT 0.045 0.123 0.61 0.15 0.0450
PCB 0.0005 0.230 0.631 8.13 2.26 0.1049
BEHP* 0.000 0.000 121.00 16.00 1.0642
Zinc 0.1335 61.519 168.563 1552.00 1198.00 61.8416
w * = Complete data set not available. Background concentrations assumed to be zero.
Table B.3.b. (Continued) Projected Bottom Sediment Concentrations (ug/g) at Site 4
Under Secondary Treatment and Non-stratified Conditions Over 5 Years
for Selected Compounds
Effi Depo: 0.1 0.2 0.25 0.3 0.4 0.5
(g/m2/day)
Btm Area km2 3.13 0.55 0.62 0.81 0.46 0.01
4,4—DDT 0.04727 0.04951 0.05062 0.05173 0.05393 0.05612
PCB 0.14655 0.17831 0.19409 0.20981 0.24106 0.27207
BEHP* 1.46157 1.93703 2.17335 2.40873 2.87670 3.34099
Zinc 67.76768 73.67120 76.60538 79.52794 85.33846 91.10330
* = Complete data set not available. Background concentrations assumed to be zero.

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Table B.3.b. (Continued) Effluent Sedimentation at Site 5 Under Secondary
Treatment and Non—stratified Conditions Over 5 Years
Depos. Area Dis. Area Sed Rate Weighting
g/ni2/day Km2 Xm2 mm/yr factor
0.10 4.93 2.34 0.026 0.012
0.15 2.59 1.17 0.039 0.009
0.20 1.42 0.75 0.052 0.008
0.25 0.67 0.63 0.065 0.008
0.30 0.04 0.04 0.078 0.001
B-26

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Table B.3.b. (Continued) Input Concentrations to Predict Bottom Sediment
Concentrations at Site 5 Under Secondary Treatment and Non-stratified
Conditions Over 5 Years for Selected Compounds
Background I Effluent I Bottom
Sedimentation I Constituents I Seds.
I I
Water Solids Total Primary Secondary
Conc. Conc. Depos. Conc. Conc. Conc.
ug/l ug/g ug/m2/day ug/g ug/g ug/g
4,4—DDT 0.046 0.125 0.61 0.15 0.0457
PCB 0.0005 0.230 0.631 8.13 2.26 0.1088
BEHP* 0.000 0.000 121.00 16.00 1.2089
Zinc 0.1335 61.519 168.563 1552.00 1198.00 43.0633
* = Complete data set not available. Background concentrations assumed to be zero.
Table B.3.b. (Continued) Projected Bottom Sediment Concentrations (ug/g) at Site 5
Under Secondary Treatment and Non-stratified Conditions Over 5 Years
for Selected Compounds
Effl Depo: 0.10 0.15 0.20 0.25 0.30
(g/m2/day)
Btm Area km2 2.34 1.17 0.75 0.63 0.04
4,4—DDT 0.04794 0.04906 0.05018 0.05129 0.05240
PCB 0.15017 0.16607 0.18191 0.19768 0.21340
BEHP* 1.59462 1.83256 2.06955 2.30560 2.54072
Zinc 50.50308 53.49513 56.47527 59.44359 62.40014
* = Complete data set not available. Background concentrations assumed to be zero.

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Table B.3.c. Effluent Sedimentation at Site 2 Under Primay Treatment
and Non-stratified Conditions Over 5 Years
Depos. Area Dis. Area Sed Rate Weighting
g/m2/day Km2 Km2 mm/yr factor
0.1 75.470 57.804 0.026 0.020
0.25 17.666 13.592 0.065 0.012
1.0 4.074 1.706 0.261 0.006
2.0 2.368 1.012 0.521 0.007
3.0 1.356 0.6869 0.782 0.007
4.0 0.669 0.5359 1.042 0.007
5.0 0.133 0.1332 1.303 0.002
B-28

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Table B.3.c. (Continued) Input Concentrations to Predict Bottom Sediment
Concentrations at Site 2 Under Primary Treatment and Non-stratified
Conditions Over 5 Years
Background I Effluent I Bottom
Sedimentation I Constituents I Seds.
I I
Water Solids Total Primary Secondary
Conc. Conc. Depos. Conc. Conc. Conc.
ugh ug/g ug/m2/day ug/g ug/g ug/g
BBP* 0.000 0.000 85.00 5.00
DNOP* 0.000 0.000 136.00 20.00
Aidrin 0.040 0.110 1.58 0.23 0.0400
4,4—DDT 0.040 0.110 0.61 0.15 0.0400
Dieldrin 0.040 0.110 0.02 0.00 0.0400
Heptachior 0.040 0.110 0.56 0.06 0.0400
PCB 0.0005 0.230 0.631 8.13 2.26 0.0123
° Arsenic 0.0140 6.451 17.677 7.00 5.00 2.8720
BEHP* 0.000 0.000 121.00 16.00
Copper 0.0420 19.354 53.031 717.00 357.00 12.5610
Mercury 0.0012 0.553 1.515 10.00 5.00 0.1490
Nickel 0.2160 99.537 272.732 118.00 129.00 4.6630
Selenium 0.0043 2.000 5.480 56.00 38.00 2.0000
Silver 0.0053 2.440 6.686 35.00 9.00 2.4400
Zinc 0.1335 61.519 168.563 1552.00 1198.00 26.1180
* = Complete data set not available. Background concentrations assumed to be zero.

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Table B.3.c. (Continued) Projected Bottom Sediment concentrations at (ug/g) Site 2
Under Primary Treatment and Non-stratified conditions Over 5 Years
Effl Depo:
0.1 0.25
1.0
2.0
3.0
4.0
5.0
(g/m2/day)
Btm Area km2
57.804 13.592
1.706
1.012
0.687
0.536
0.133
BBP*
0.33944 0.84354
3.27661
6.30997
9.12622
11.74784
14.19435
DNOP*
0.54310 1.34966
5.24257
10.09595
14.60194
18.79655
22.71097
Aidrin
0.04615 0.05528
0.09936
0.15432
0.20535
0.25284
0.29717
4,4—DDT
0.04228 0.04566
0.06197
0.08231
0.10120
0.11878
0.13519
Dieldrin
0.03992 0.03980
0.03923
0.03852
0.03785
0.03724
0.03666
Heptachior
0.04208 0.04516
0.06005
0.07860
0.09583
0.11187
0.12684
PCB
0.06143 0.10947
0.34135
0.63045
0.89885
1.14871
1.38187
Arsenic
3.16273 3.18558
3.29586
3.43335
3.56099
3.67982
3.79071
BEHP*
0.48320 1.20080
4.66434
8.98243
12.99144
16.72340
20.20608
Copper
15.89457 20.06923
40.21835
65.33878
88.66114
110.37180
130.63226
°
Mercury
0.21929 0.27753
0.55862
0.90906
1.23441
1.53729
1.81993
Nickel
12.38446 13.01334
16.04863
19.83281
23.34612
26.61665
29.66871
Selenium
2.21564 2.53589
4.08160
6.00869
7.79783
9.46333
11.01759
Silver
2.57002 2.76312
3.69513
4.85709
5.93588
6.94011
7.87727
Zinc
34.92373 43.95700
87.55637
141.91283
192.37855
239.35684
283.19713
* = Complete data set not available. Background concentrations assumed to be zero.

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Table B.3.c. (Continued) Effluent Sedimentation at Site 4 Under Prima
Treatment and Non—stratified Conditions Over 5 Years
Depos. Area Dis. AreaSed Rate Weighting
g/m2/day Km2 Km2 mm/yr factor
0.1 61.02 47.43 0.026 0.020
0.25 13.59 7.796 0.065 0.008
0.5 5.79 2.634 0.130 0.006
1.0 3.16 0.74 0.261 0.003
1.5 2.42 0.91 0.391 0.006
2.0 1.51 0.57 0.521 0.005
2.5 0.94 0.45 0.652 0.005
3.0 0.49 0.36 0.782 0.005
3.5 0.13 0.13 0.912 0.002
B-3 1

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Table B.3.c. (Continued) Input Concentrations to Predict Bottom Sediment
Concentrations at site 4 Under Primary Treatment and Non-stratified
Conditions Over 5 Years
Background
Sedimentation
Effluent
Constituents
Bottom
Seds.
Water Solids Total Primary Secondary
Conc. Conc. Depos. Conc. Conc. Conc.
ug/l ug/g ug/m2/day ug/g ug/g ug/g
BBP*
0.000
0.000
85.00
5.00
DNOP*
0.000
0.000
136.00
20.00
Aidrin
0.040
0.110
1.58
0.23
0.0400
4,4—DDT
0.040
0.110
0.61
0.15
0.0400
Dieldrin
0.040
0.110
0.02
0.00
0.0400
w
“
Heptachlor
PCB
Arsenic
0.0005
0.0140
0.040
0.230
6.451
0.110
0.631
17.677
0.56
8.13
7.00
0.06
2.26
5.00
0.0400
0.0173
5.5330
BEHP*
0.000
0.000
121.00
16.00
copper
0.0420
19.354
53.031
717.00
357.00
17.8830
Mercury
0.0012
0.553
1.515
10.00
5.00
0.1710
Nickel
0.2160
99.537
272.732
118.00
129.00
9.2420
Selenium
0.0043
2.000
5.480
56.00
38.00
2.0000
Silver
0.0002
0.100
0.274
35.00
9.00
0.1000
Zinc
0.1335
61.519
168.563
1552.00
1198.00
47.5450
* = Complete data set not available. Background concentrations assumed to be zero.

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Table B.3.c. (Continued) Projected Bottom Sediment Concentrations (ug/g) at Site 4 Under Primary
Treatment and Non—stratified Conditions Over 5 Years
Effi Depo:
(g/m2/day)
Btm Area km2
0.1
47.43
0.33944
0.54310
0.04615
0.04228
0.03992
0.04208
0. 06602
5. 60923
0. 48320
20. 78757
0.23952
16. 59435
2. 21564
0. 23937
54. 62352
0.25
7.80
0. 84354
1. 34966
0. 05528
0. 04566
0.03980
0.04516
0. 11404
5. 61751
1. 20080
24.93309
0. 29763
17.19816
2. 53589
0. 44635
63. 53949
0.5
2.63
1. 67050
2. 67280
0. 07027
0. 05120
0. 03961
0. 05022
0.19281
5. 63109
2. 37801
31. 73367
0.39297
18. 18869
3.06126
0. 78589
78. 16580
1.0
0.74
3. 27661
5. 24257
0.09936
0. 06197
0. 03923
0. 06005
0.34579
5. 65748
4. 66434
44.94 159
0. 57814
20. 11247
4.08160
1. 44534
106. 57270
1.5
0.91
4. 82 197
7.71515
0. 12736
0. 07234
0. 03887
0. 06950
0. 49299
5. 68287
6. 86421
57. 65000
0. 75631
21. 96349
5. 06337
2.07984
133 • 90527
2.0
0.57
6. 30997
10. 09595
0. 15432
0.08231
0. 03852
0. 07860
0. 63472
5. 70731
8. 98243
69.88671
0. 92786
23.74580
6. 00869
2.69080
160.22332
BBP*
DNOP*
Aidrin
4,4-DDT
Die ldrin
Heptachior
PCB
Arsenic
BEHP*
Copper
i Mercury
Nickel
Selenium
Silver
Zinc
* = Complete data set not available. Background concentrations assumed to be zero.
2.5
0.45
7.74375
12. 39000
0. 18030
0. 09193
0.03818
0. 08737
0. 77129
5. 73086
11. 02346
81. 67749
1. 09316
25. 46317
6.91956
3.27949
185.58231
3.0
0.36
9. 12622
14.60194
0. 20535
0. 10120
0.03785
0. 09583
0. 90297
5. 75357
12.99144
93. 04630
1. 25254
27. 11908
7. 79783
3.84712
210.03373
3.5
0.13
10. 46007
16. 73612
0. 22951
0.11014
0. 03754
0. 10399
1. 03002
5. 77549
14.89022
104.01538
1. 40632
28. 71676
8. 64522
4.39478
233.62543

-------
Table B.3.c. (Continued) Effluent Sedimentation at Site 5 Under Pritnary
Treatment and Non-stratified Conditions Over 5 Years
Depos. Area Dis. Area Sed Rate Weighting
g/m2/day Km2 Km2 mm/yr factor
0.10 37.62 27.19 0.026 0.019
0.25 10.43 3.87 0.065 0.007
0.50 6.56 3.41 0.130 0.012
1.00 3.15 1.54 0.261 0.011
1.50 1.61 0.98 0.391 0.010
2.00 0.63 0.62 0.521 0.009
2.50 0.01 0.01 0.652 0.000
B - 314

-------
Table B.3.c. (Continued) Input Concentrations to Predict Bottom Sediment
Concentrations at Site 5 Under Primary Treatment and Non-stratified
Conditions Over 5 Years
BBP*
DNOP*
Aidrin
4,4-DDT
Dieldrin
Heptachlor
PCB
Arsenic
BEHP*
Copper
Mercury
Nickel
Selenium
Silver
Zinc
0.000
0.000
0.040
0.040
0.040
0.040
0.230
6.451
0.000
19.354
0.553
99. 537
2.000
0.100
61. 519
85.00
136.00
1.58
0.61
0.02
0.56
8.13
7.00
121.00
717.00
10.00
118.00
56.00
35.00
1552.00
5.00
20.00
0.23
0.15
0.00
0.06
2.26
5.00
16.00
357.00
5.00
129.00
38.00
9.00
1198.00
Bottom
Seds.
Background
I
Effluent
I
Sedimentation
I
I
Constituents
I
I
Secondary
Conc.
Conc.
Water Solids Total Primary
Conc. Conc. Depos. Conc.
ugh ug/g ug/m2/day ug/g ug/g ug/g
0.000
0.000
0.110
0 • 110
0.110
0.110
0.631
17. 677
0.000
53.031
1.515
272. 732
5.480
0.274
168. 563
0. 0005
0. 0140
0. 0420
0. 0012
0. 2160
0. 0043
0. 0002
0. 1335
0. 0400
0. 0400
0. 0400
0. 0400
0. 0110
4. 6200
6. 7100
0. 1050
4.8760
2. 0000
0. 1000
25. 0290
* = Complete data set not available. Background concentrations assumed to be zero.

-------
Table B.3.c. (Continued) Projected Bottom Sediment Concentrations (ug/g) at Site 5
Under Primary Treatment and Non-stratified Conditions Over 5 Years
Effl Depo: 0.10 0.25 0.50 1.00 1.50 2.00 2.50
(g/m2/day)
Btm Area km2
27.19 3.87
3.41
1.54
0.98
0.62
0.01
BBP*
0.33944 0.84354
1.67050
3.27661
4.82197
6.30997
7.74375
DNOP*
0.54310 1.34966
2.67280
5.24257
7.71515
10.09595
12.39000
Aidrin
0.04615 0.05528
0.07027
0.09936
0.12736
0.15432
0.18030
4,4—DDT
0.04228 0.04566
0.05120
0.06197
0.07234
0.08231
0.09193
Dieldrin
0.03992 0.03980
0.03961
0.03923
0.03887
0.03852
0.03818
Heptachior
0.04208 0.04516
0.05022
0.06005
0.06950
0.07860
0.08737
PCB
0.06023 0.10828
0.18711
0.34020
0.48750
0.62934
0.76600
Arsenic
4.76982 4.78310
4.80489
4.84720
4.88791
4.92710
4.96487
w
BEHP*
0.48320 1.20080
2.37801
4.66434
6.86421
8.98243
11.02346
0 ’
Copper
Mercury
10.51522 14.72191
0.17884 0.23732
21.62282
0.33325
35.02562
0.51957
47.92154
0.69884
60.33880
0.87146
72.30355
1.03778
Nickel
12.58029 13.20800
14.23774
16.23767
18.16196
20.01483
21.80018
Selenium
2.21564 2.53589
3.06126
4.08160
5.06337
6.00869
6.91956
Silver
0.23937 0.44635
0.78589
1.44534
2.07984
2.69080
3.27949
Zinc
33.92252 42.96175
57.79027
86.58989
114.30032
140.98222
166.69179
* = Complete data set not available. Background concentrations assumed to be zero.

-------
Table B.3.d. Effluent Sedimentation at Site 2 Under Primary Treatment
and Stratified Conditions Over 6 Months
Depos. Area Dis. Area Sed Rate Weighting
g/m2/day Rm2 Km2 mm/yr factor
0.1 74.282 39.522 0.026 0.014
0.25 34.76 31.22 0.065 0.027
2.0 3.540 1.502 0.521 0.011
4.0 2.038 0.847 1.042 0.012
6.0 1.191 0.645 1.564 0.014
8.0 0.546 0.369 2.085 0.010
10.0 0.177 0.168 2.606 0.006
12.0 0.009 0.009 3.127 0.000
B-37

-------
Table B.3.d. (Continued) Input Concentrations to Predict Bottom Sediment
Concentrations at Site 2 Under Primary Treatment and Stratified
Conditions Over 6 Months
Background I Effluent I Bottom
Sedimentation I Constituents I Seds.
I I
Water Solids Total Primary Secondary
Conc. Conc. Depos. Conc. Conc. Conc.
ug/l ug/g ug/m2/day ug/g ug/g ug/g
BBP*
0.000
0.000
85.00
5.00
DNOP*
0.000
0.000
136.00
20.00
Aldrin
0.040
0.110
1.58
0.23
0.0400
4,4—DDT
0.040
0.110
0.61
0.15
0.0400
Dieldrin
0.040
0.110
0.02
0.002
0.0400
Heptachlor
0.040
0.110
0.56
0.06
0.0400
w
PCB
0.0005
0.230
0.631
8.13
2.26
0.0123
Arsenic
0.0140
6.451
17.677
7.00
5.00
2.8720
BEHP*
0.000
0.000
121.00
16.00
Copper
0.0420
19.354
53.031
717.00
357.00
12.5610
Mercury
0.0012
0.553
1.515
10.00
5.00
0.1490
Nickel
0.2160
99.537
272.732
118.00
129.00
4.6630
Selenium
0.0043
2.000
5.480
56.00
38.00
2.0000
Silver
0.0053
2.440
6.686
35.00
9.00
2.4400
Zinc
0.1335
61.519
168.563
1552.00
1198.00
26.1180
* = Complete data set not available. Background concentrations assumed to be zero.

-------
Table B.3.d. (Continued) Projected Bottom Sediment Concentrations (ug/g) at Site 2
Under Primary Treatment and Stratified Conditions Over 6 Months
Eff 1 Depo:
(g/m2/day)
Btm Area km2
0.1 0.25
39.522 31.220
4.0 6.0
0.847 0.645
8.0 10.0
0.369 0.168
BBP*
DNOP*
Aidrin
4, 4-DDT
Dieldrin
Heptachior
PCB
Arsenic
BEHP*
Copper
Mercury
° Nickel
Selenium
Silver
Zinc
0.03660
0. 05856
0. 04066
0. 04025
0. 03999
0. 04022
0. 01760
2.90335
0. 05210
12.92043
0. 15658
5. 49555
2.02325
2.45402
27.06745
2.0
1.502
0. 72604
1. 16166
0. 053 15
0.04487
0.03983
0.04444
0. 08343
2.93659
1. 03354
18.63371
0. 23645
6. 40847
2.46125
2.71812
39.44158
0.09144
0.14630
0. 04166
0. 04061
0. 03998
0. 04056
0. 02283
2.90599
0. 13016
13.37488
0. 16293
5. 56816
2. 05809
2.47503
28.05172
1. 43978
2. 30364
0. 06609
0. 04965
0. 03966
0. 04881
0. 15157
2.97100
2. 04957
24. 54837
0.31914
7. 35357
2.91468
2.99152
52. 25185
2.14153
3.42645
0. 07880
0.05436
0. 03950
0. 05310
0. 21858
3. 00484
3. 04853
30. 36369
0. 40045
8. 28279
3. 36050
3.26033
64.84697
2.83159
4. 53055
0.09130
0. 05899
0. 03933
0. 05732
0. 28447
3.03811
4.03085
36. 08214
0. 48039
9. 19654
3.79889
3. 52467
77. 23229
12.0
0.009
4. 17780
6. 68448
0. 11569
0. 06802
0. 03902
0. 06556
0.41300
3. 10302
5. 94722
47. 23797
0. 63636
10. 97913
4. 65413
4.04034
101.39419
3. 51025
5. 61641
0.10360
0. 06354
0. 03917
0. 06147
0. 34927
3. 07084
4.99695
41. 70613
0.55902
10.09519
4. 23004
3.78463
89. 41302
* = Complete data set not available. Background concentrations assumed to be zero.

-------
Table B.3.d. (Continued) Effluent Sedimentation at Site 4 Under PriTnary
Treatment and Stratified Conditions Over 6 Months
Depos. Area Dig. Area Sed Rate Weighting
g/m2/day Km2 Km2 mm/yr factor
0.1 71.71 51.64 0.026 0.019
0.25 20.07 15.99 0.065 0.015
1.0 4.08 1.66 0.261 0.006
2.0 2.42 0.74 0.521 0.005
3.0 1.68 0.62 0.782 0.007
4.0 1.06 0.49 1.042 0.007
5.0 0.57 0.37 1.303 0.007
6.0 0.20 0.2 1.564 0.004
B 1iO

-------
Table B.3.d.
(Continued) Input Concentrations to Predict Bottom Sediment
Concentrations at Site 4 Under Primary Treatment and Stratified
Conditions Over 6 Months
Background
Sedimentation
Effluent
I
Bottom
Constituents
I
Seds.
Water
Solids
Total
Primary
Secondary
Conc.
Conc.
Depos.
Conc.
Conc.
Conc.
ugh
ug/g
ug/m2/day
ug/g
ug/g
ug/g
BBP*
0.000
0.000
85.00
5.00
DNOP*
0.000
0.000
136.00
20.00
Aidrin
0.040
0.110
1.58
0.23
0.0400
4,4—DDT
0.040
0.110
0.61
0.15
0.0400
Dieldrin
0.040
0.110
0.02
0.00
0.0400
Heptachior
0.040
0.110
0.56
0.06
0.0400
j
PCB
0.0005
0.230
0.631
8.13
2.26
0.0173
-
Arsenic
0.0140
6.451
17.677
7.00
5.00
5.5330
BEHP*
0.000
0.000
121.00
16.00
Copper
0.0420
19.354
53.031
717.00
357.00
17.8830
Mercury
0.0012
0.553
1.515
10.00
5.00
0.1710
Nickel
0.2160
99.537
272.732
118.00
129.00
9.2420
Selenium
0.0043
2.000
5.480
56.00
38.00
2.0000
Silver
0.0002
0.100
0.274
35.00
9.00
0.1000
Zinc
0.1335
61.519
168.563
1552.00
1198.00
47.5450
* = Complete
data set
not available.
Background concentrations
assumed to be zero.

-------
Table B.3.d.
(Continued) Projected Bottom Sediment
Under Primary Treatment and Stratified
Concentrations (ug/g) at Site 4
Conditions Over 6 Months
Effi Depo:
0.1 0.25 1.0 2.0
3.0 4.0
5.0
6.0
(g/m2/day)
Btm Area km2
51.64 15.99 1.66 0.74
0.62 0.49
0.37
0.20
BBP*
0.03660 0.09144 0.36458 0.72604
1.08443 1.43978
1.79213
2.14153
DNOP*
0.05856 0.14630 0.58332 1.16166
1.73508 2.30364
2.86741
3.42645
Aidrin
0.04066 0.00170 0.04661 0.05315
0.05965 0.06609
0.07247
0.07880
4,4—DDT
0.04025 0.00066 0.04244 0.04487
0.04727 0.04965
0.05202
0.05436
Dje ldrjn
0.03999 0.00002 0.03991 0.03983
0.03974 0.03966
0.03958
0.03950
Heptachior
0.04022 0.00060 0.04223 0.04444
0.04663 0.04881
0.05096
0.05310
PCB
0.02255 0.00875 0.05385 0.08834
0.12254 0.15645
0.19007
0.22341
Arsenic
5.54122 0.00753 5.54685 5.55306
5.55921 5.56531
5.57136
5.57736
BEHP*
0.05210 0.13016 0.51898 1.03354
1.54371 2.04957
2.55115
3.04853
j
r.J
Copper
Mercury
Nickel
18.19618 0.77131 20.89371 23.86665
0.17839 0.01076 0.21630 0.25809
10.03475 0.12694 10.45152 10.91084
26.81430 29.73699
0.29951 0.34059
11.36625 11.81780
32.63502
0.38132
12.26555
35.50873
0.42171
12.70954
Selenium
2.02325 0.06024 2.23161 2.46125
2.68893 2.91468
3.13853
3.36050
Silver
0.11503 0.03765 0.24969 0.39810
0.54525 0.69116
0.83583
0.97929
Zinc
48.30822 1.66955 54.11280 60.50999
66.85277 73.14183
79.37785
85.56150
* = Complete
data set not available. Background
concentrations assumed to
be zero.

-------
Table B.3.d. (Continued) Effluent Sedimentation at Site 5 Under Prima
Treatment and Stratified Conditions Over 6 Months
Depos. Area Dis. Area Sed Rate Weighting
g/m2/day km2 km2 mm/yr factor
0.10 50.15 37.79 0.026 0.020
0.25 12.36 8.92 0.065 0.012
1.50 3.44 1.37 0.391 0.011
2.00 2.07 0.72 0.521 0.007
2.50 1.35 0.67 0.652 0.009
3.00 0.68 0.52 0.782 0.008
3.50 0.16 0.15 0.912 0.003
4.00 0.01 0.01 1.042 0.000
B-i 3

-------
Table B.3.d. (Continued) Input Concentrations to Predict Bottom Sediment
Concentrations at Site 5 Under Primary Treatment and Stratified
Conditions Over 6 Months
Background
I
Effluent
I
Bottom
Sedimentation
I
I
Constituents
I
I
Seds.
Water
Solids
Total
Primary
Secondary
Conc.
Conc.
Depos.
Conc.
Conc.
Conc.
ug/l
ug/g
ug/m2/day
ug/g
ug/g
ug/g
BBP*
0.000
0.000
85.00
5.00
DNOP*
0.000
0.000
136.00
20.00
Aidrin
0.040
0.110
1.58
0.23
0.0400
4,4—DDT
0.040
0.110
0.61
0.15
0.0400
Dieldrin
0.040
0.110
0.02
0.00
0.0400
Heptachlor
0.040
0.110
0.56
0.06
0.0400
PCB
0.0005
0.230
0.631
8.13
2.26
0.0110
‘
Arsenic
0.0140
6.451
17.677
7.00
5.00
4.6200
BEHP*
0.000
0.000
121.00
16.00
copper
0.0420
19.354
53.031
717.00
357.00
6.7100
Mercury
0.0012
0.553
1.515
10.00
5.00
0.1050
Nickel
0.2160
99.537
272.732
118.00
129.00
4.8760
Selenium
0.0043
2.000
5.480
56.00
38.00
2.0000
Silver
0.0002
0.100
0.274
35.00
9.00
0.1000
Zinc
0.1335
61.519
168.563
1552.00
1198.00
25.0290
* = Complete
data set
not available. Background concentrations
assumed to be zero.

-------
Table B.3.d. (Continued) Projected Bottom Sediment Concentrations (ug/g) at Site 5
(Soft-bottom) Under Primary Treatment and Stratified Conditions Over 6 Months
Effl Depo: 0.10 1.50 2.00 2.50 3.00 3.50 4.0
(g/m2/day)
Btin Area km2 37.79 1.37 0.72 0.67 0.52 0.15 0.01
BBP*
0.03660
0.54569
0.72604
0.90561
1.08443
1.26248
1.43978
DNOP*
0.05856
0.87311
1.16166
1.44898
1.73508
2.01996
2.30364
Aidrin
0.04066
0.04989
0.05315
0.05641
0.05965
0.06287
0.06609
4,4—DDT
0.04025
0.04366
0.04487
0.04607
0.04727
0.04847
0.04965
Dieldrin
0.03999
0.03987
0.03983
0.03979
0.03974
0.03970
0.03966
Heptachior
0.04022
0.04334
0.04444
0.04554
0.04663
0.04772
0.04881
PCB
0.01631
0.06493
0.08215
0.09930
0.11637
0.13338
0.15031
Arsenic
4.63615
4.65032
4.65534
4.66033
4.66531
4.67026
4.67519
BEHP*
0.05210
0.77681
1.03354
1.28917
1.54371
1.79717
2.04957
copper
7.12029
11.37384
12.88063
14.38101
15.87500
17.36266
18.84402
k
“
Mercury
Nickel
0.11296
5.70669
0.17220
6.37955
0.19319
6.61790
0.21409
6.85524
0.23489
7.09157
0.25561
7.32690
0.27625
7.56123
Selenium
2.02325
2.34668
2.46125
2.57533
2.68893
2.80204
2.91468
Silver
0.11503
0.32406
0.39810
0.47183
0.54525
0.61836
0.69116
Zinc
25.98792
35.13167
38.37080
41.59613
44.80773
48.00571
51.19015
* = Complete data set not available. Background concentrations assumed to be zero.

-------
Table B.3.d. (Continued) Projected Bottom Sediment Concentrations (ug/g) at Site 5
(Hard-bottom) Under Primary Treatment and Stratified Conditions Over 6 Months
Effl Depo: 0.10 1.50 2.00 2.50 3.00 3.50 4.0
(g/m2/day)
Btm Area km2 37.79 1.37 0.72 0.67 0.52 0.15 0.01
BBP*
4.21089 37.29623
43.38311
48.09242
51.84428
54.90373
57.44625
DNOP*
6.73742 59.67398
69.41298
76.94787
82.95084
87.84596
91.91401
Aldrin
0.11629 0.71572
0.82600
0.91132
0.97930
1.03473
1.08079
4,4—DDT
0.06824 0.29010
0.33092
0.36250
0.38766
0.40818
0.42523
Die ldrin
0.03901 0.03122
0.02979
0.02868
0.02780
0.02708
0.02648
Heptachior
0.06576 0.26817
0.30540
0.33421
0.35716
0.37588
0.39144
PCB
0.62175 3.69659
4.26228
4.69994
5.04863
5.33296
5.56926
Arsenic
6.47865 6.69216
6.73144
6.76183
6.78604
6.80578
6.82219
BEHP*
5.99433 53.09229
61.75713
68.46098
73.80185
78.15707
81.77643
Copper
53.91572 325.4668
375.42543
414.07754
444.87126
469.98199
490.85002
i

Mercury
Nickel
Selenium
1.0210 4.698
100.45177 107.6382
4.67511 25.69406
5.3746
108.96038
29.56101
5.89804
109.98329
32.55281
6.31503
110.79823
34.93635
6.65506
111.46278
36.88000
6.93764
112.01504
38.49525
Silver
1.82894 15.41339
17.91259
19.84618
21.38665
22.64282
23.68676
Zinc
135.35770 715.5114
822.24513
904.8232
970.6122
1024.2599
1068.8433
* = Complete data set not available. Background concentrations assumed to be zero.

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REFERENCES
Barr, B. 1987, Dredging Handbook: A primer for Dredging in the Coastal Zone of
Massachusetts. Mass. Coastal Zone Management.
Bothner, M.H., 1987. Geochemical and Geological Studies of Sediments in Boston
Harbor and Massachusetts Bay (abs.), in Program, Science and Policy of Boston
Harbor and Massachusetts Bay; Planning for the Twenty-First Century: Annual
Boston Harbor/Massachusetts Bay Symposium of the Massachusetts Bay Marine
Studies Consortium, November 12-13.
Butman, B., 1978. On the Dynamics of Shallow Water Currents in Massachusetts Bay
and on the New England Continental Shelf: Woods Hole Oceanographic Institution
Report WHOI 77-15. Woods Hole, MA.
Butman, B., 1987. Observations of Currents and Sediment Movement in Western
Massachusetts Bay During Winter and Spring, 1987 (abs.), in Program, Science and
Policy of Boston Harbor and Massachusetts Bay; Planning for the Twenty-First
Century: Annual Boston Harbor/Massachusetts Bay Symposium of the Massachusetts
Bay Marine Studies Consortium, November 12-13.
Cameron, B. and R.S. Naylor, 1976. General Geology of Southeastern New England, in
Cameron, B. (ed.) Geology of Southeastern New England: 68th Annual Meeting, New
England Intercollegiate Geological Conference. Boston, MA.
Doering, P.H. and C.A. Oviatt, 1986. Application of Filtration Rate Models to Field
Populations of Bivalves: An Assessment Using Experimental Mesocosms. Marine
Ecol. Prog. Ser . 31:265-275.
Doering, P.H., C.A. Oviatt, and J.R. Kelly, 1986. The Effects of the Filter-Feeding
Clam Kercenaria mercenaria on Carbon Cycling in Experimental Marine Mesocosms.
J. Marine Research i114:839_861.
Fitzgerald, M.G., 1980. Anthropogenic Influence of the Sedimentary Regime of an
Urban Estuary — Boston Harbor: Woods Hole Oceanographic Institution Report
WHOI-80-38. Woods Mole, MA
Kaye, C., 1976. Outline of Pleistocene Geology of the Boston Basin, in Cameron, B.
(ed.) Geology of Southeastern New England: 68th Annual Meeting, New England
Intercollegiate Geological Conference. Boston, MA.
Kolb, B., 1988. Project Engineer, Camp, Dresser & McKee, Consultant to MWRA,.
Personal Communication.
Maughan, J.T., 1986. Relationship Between Macrobenthic Infauna and Organic
Carbon. Ph.D. Thesis, University of Rhode Island, Graduate School of
Oceanography. Narragansett, RI
B-Li 7

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REFERENCES (Continued)
Meisburger, E.P., 1976. Geomorphology and Sediments of Western Massachusetts Bay.
Technical Paper 76-3, Coastal Engineering Research Center. Fort Belvoir, VA, pp
78.
MDC, 19811. Application for a Waiver of Secondary Treatment for the Nut Island and
Deer Island Treatment Plants, Vol. I. Metropolitan District Commission (MDC).
Boston, MA.
MDC 19814. Application for a Waiver of Secondary Treatment for the Nut Island and
Deer Island Treatment Plants, Appendix 1$: Outer Boston Harbor Prospective
Sewage Outfall Area REMOTS Survey, MSI Report No. BH 070981101, prepared by
Marine Surveys, Inc.
MWRA, STFP V, 1987. Deer Island Secondary Treatment Facilities Plan, Volume V,
Effluent Outfall. Massachusetts Water Resources Authority (MWRA).
Charlestown, MA.
MWRA, STFP, V,C, 1987. Deer Island Secondary Treatment Facilities Plan, Volume V,
Appendix C, Public Health Risk Assessment.
MWRA, STFP, V,N, 1987. Deer Island Secondary Treatment Facilities Plan, Volume V,
Appendix N, ROV Reconnaissance I.
MWRA, STFP, V,O, 1987. Deer Island Secondary Treatment Facilities Plan, Volume V,
Appendix 0, ROV Reconnaissance II.
MWRA, STFP, V,P, 1987. Deer Island Secondary Treatment Facilities Plan, Volume V,
Appendix P, REMOTS Reconnaissance I.
MWRA, STFP, V,Q, 1987. Deer Island Secondary Treatment Facilities Plan, Volume V,
Appendix Q, REMOTS Reconnaissance II.
MWRA, STFP, V,S, 1987. Deer Island Secondary Treatment Facilities Plan, Volume V,
Appendix S, Benthic Chemistry Sampling.
MWRA, STFP, V,R, 1987. Deer Island Secondary Treatment Facilities Plan, Volume V,
Appendix R, Sediment Grain Size Sampling.
Oldale, R.E., E. Uchupi, and K.E. Prada, 1973. Sedimentary Framework of the Western
Gulf of Maine and the Southeastern Massachusetts Offshore Area. U.S. Geological
Survey Professional Paper 757. Washington, D.C.
Rosen, P., in process. Stratigraphy of Back Bay, Boston Harbor, Between 500
Boy].ston Street.
Schlee, J.S. and B. Butman, 19714. Adjustment of Inner Shelf Sediments to Bottom
Currents off Eastern Massachusetts, Mern. Inst. Geol. Aguiture . No. 7.
B-’ 18

-------
REFERENCES (Continued)
Stone and Webster Engineering, Inc., 1987. Technical Memorandum of Offshore
Geotechnical Investigations and Design Criteria for the Inter-Island Transport
System. Boston, MA.
Tetra-Tech, 19814. Technical Review of Boston’s Deer Island and Nut Island Sewage
Treatment Plants Section 310(h) Waiver Application for Modification of Secondary
Treatment Requirements for Discharge into Marine Waters. Prepared for U.S.
Environmental Protection Agency. Washington, D.C.
Tucholke, B.E., and C.H. Hollister, 1.973. Lake Wisconsin Glaciation of the South
West Gulf of Maine: New Evidence from Marine Environments. Geol. Soc. Am.
Bull . 814:3229-3296.
U.S. EPA, 1982. Revised Section 301(h) Technical Support Document. Government
Printing Office. Washington, D.C.
Weston Geophysical, Inc., 1987. Seismic Surveys, Deer Island Outfall Sewer Project
of the Massachusetts Water Resources Authority.
Willet, C.F., 1972. Massachusetts Coastal Mineral Inventory Survey: Raytheon.
Portsmouth, R.I.
B- 1 49

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APPENDIX C
MARINE ECOSYSTEMS
AFFECTED ENV I RONMENT

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APPENDIX C
MARINE ECOSYSTEMS
C. 1 AFFECTED ENVIRONMENT
C.1.1 OVERVIEW
This section presents information on baseline biological conditions in the area
potentially affected by the construction and operation of the effluent conveyance
and dispersion structures. Biological communities described include infaunal and
epifaunal benthic communities, phytoplankton, zooplankton, fish, marine mammals and
sea birds. Data used to describe these communities include data collected by MWRA
(STFP, V, and Appendices, 1987) as well as historical data. Table C.i.a presents a
sitmm ry of the major sources of information. Figure C.i.a presents the locations of
the MWRA 1987 survey stations. The area under most intense evaluation in this
appendix is the general transect starting nearshore at site 2 and extending to site
5.
TABLE C.i.a SUMMARY OF MARINE ECOSYSTEM SURVEYS
Survey
Dates Sampled
Major Sources
Benthic Biology
Soft Bottom
Hard Bottom
3/87, 5/87, 8/87;
7/814, 6/82, 6/79, 7/78
14-5/87, 7/87, 8/87, 7/814
MWRA, STFP V,T, 1987;
MDC, 19814
Sediment Grain Size
3/87, 5/87, 8/87
MWRA, STFP V,R, 1987
Benthic Chemistry
14/87, 6/87,8/87
MWRA, STFP V,S, 1987
REMOTS Reconnaissance
2-3/87, 8/87
MWRA, STFP V,P, and Q, 1987;
MDC, 19814
ROV Reconnaissance
11-12/86, 7/87
MWRA, STFP V,N and 0, 1987
Phytoplankton
Nutrient Analysis
7/15/87 - 9/8/87;
3/73 — 14/714
1977— 1985
7/15/87 - 9/8/87
MWRA, STFP V,Z, 1987;
Parker, 19714
NMFS
MWRA, STFP V,Y, 1987
Fish and Epibenthic
Shellfish
14/87, 7/87, 9/87
MWRA, STFP V, 1987; DMF, 1986
TRIGOM, 19714
C-i

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8 PRIMARY PRODUC11V1TY
FISH AND EPIBENTHIC
— — REMOTS STATIONS—FIRST SURVEY
— REMOTS STATIONS—SECOND SURVEY
• NUTRIENTS SAMPLING
SECOND ROV
A SOFT—BOTTOM TRANSECS
0 HARD—BOTTOM TRANSECTS
I
STATUTE MILES
NAUTICAL MILES
BOSTON
i’i ‘
Allerton
ADAPTED FROM: MWRA.
STFF. V, B, 1987
i ictit i ; C.I.a. 1 OCAT1ON OF MWD SAMPLIN(; IJOCATIONS

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C. 1.2 MACROBENTHOS
The marine macrobenthic community is likely to be one of the better indicators of’
long-term environmental conditions of a marine or estuarine ecosystem because the
adult stages of’ this community are relatively non—motile and long-lived. The
benthos can reflect the more long-term environmental conditions of’ the water and
sediments prior to the time of sampling while planktonic organisms often reflect
more short-term conditions indicative of the time of sampling. Although fish have a
relatively long life span, they are mobile and often migratory and seasonal and can
avoid an area which may be less suitable due to a transient condition such as lack
of food.
C.1.2.1 Benthic Epifauna
The seafloor of Massachusetts Bay is very heterogeneous due to irregular changes in
sediment ranging from patches of’ mud to areas of’ cobbles and boulders
(Appendix B). Mobile and sessile epifauna generally exist where pebbles cobbles and
boulders are most prevalent, while infaunal communities generally exist in the soft
bottom mud patches.
The epifauna biomass in the study area and Massachusetts Bay in general appears to
increase between winter and summer. This increase in biomass is due to build-up of
dense aggregations of tubiculous species on rock surfaces during periods of low
energy. During these periods, almost all hard surfaces are covered with
biologically—bound, silt—clay size material. This “biogenic mud mat” contains some
species that are otherwise typically infaunal. This phenomenon has been observed in
several surveys (MWRA, STFP, V O,P,Q, and S, 1987). It is likely that this animal
sediment complex builds up in the low-energy summer months and is periodically
removed during periods of high wave energy (Appendix B).
C.1.2.1.1 Epifaunal Species Cc iposition and Abundance
Extensive epifaunal surveys were conducted by MWRA in 1987 (MWRA, STFP, V N,O,P,Q,
and T, 1987). From the information obtained in these surveys it can be seen that
variations In epifaunal community structures between different sites relate to
C-3

-------
differences in bottom types in the study area. The heterogenous seafloor in
Massachusetts Bay ranges from mud to sand to cobble to boulders. Different
epifaunal assemblages are associated with these different bottom types. At least
six different bottom types and associated epifaunal assemblages can be characterized
from review of the 1987 ROV surveys. Table C.1.b presents a summary of this
information. Figure C.1.b shows where in the study area these bottom types are
known to occur.
Two hard bottom sites were studied extensively in 1987, MWRA sites 5 and 3.5
(Figure C.1.a). In general, the substratum at site 5 is consistent with sediment
type category V on Table C.1.b. This site consists of a large flat plain of pebble
interspersed with patches of mud and sand with a few small scattered boulders. The
substratum at site 3.5 is consistent with sediment type category IV on Table
C.1.b. This site generally consists of a pebble pavement with no large mud patches
but with some sediment accumulation between the pebbles (MWRA, STFP, V,T, 1987).
The following is a description of the epifaunal assemblages at these specific sites
based on MWRA, STFP, V,T (1987).
The rock surfaces at site 3.5 were covered with sponges, hydroids, bryozoans and
ascidians. Dominant sponge species included Halichondria panicea (approximately
5 percent cover) and Hymedesmia sp. (approximately 5 percent cover). The bryozoan
Schimavella auriculata was present at 0.5 to 1.1 percent cover over three months
while the ascidians Didemnum albidum and Aplidium palladium accounted for 0.7 to
1.7 percent cover. The hydroid/bryozoan canopy increased from approximately
25 percent cover to approximately 35 percent cover from May to August, while percent
cover of unconsolidated thick sediment decreased from approximately J45 percent cover
to nearly zero percent during the same time period. The large sea anemones
Ketridium senile and Urticina crassicornis were abundant at this site and the tube
dwelling cerianthid (Cerianthus borealis) occured frequently in sediments between
cobbles (MWRA, STFP, V,T, 1987).
Motile species at site 3.5 included several fish species such as winter flounder
(Pseudopleuronectes americanus), cunner (Tautogolabrus adspersus), pollock
(Pollachius virens) and sculpin (Myoxocephalus sp.) A few lobsters and numerous
cancer crabs were also present. Smaller motile species observed included the
molluscs Buccinum undatum, Neptunea decemocostata, Colus stimpsoni and Placopecten
C_LI

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TABLE C. 1 .b SUMMARY OF GENERAL B(YfTOM TYPES AND ASSOCIATED EPIFAUNAL ASSENBLAGES
U i
Sediment
Characteristics
Bottom
Topography
Sessile
Epifauna
Motile
Epifauna
I. Homogeneous soft
flat with worm or
very sparse;
occassional winter
bottom with high
amphipod tubes and
occasional solitary
flounder, Jonah crab,
silt/clay content
excavation pits
hydroid
scallop
II. Homogeneous soft
Mostly flat, occasional
extremely sparse
occasional to abundant
bottom with low
ripple; worm or amphipod
winter flounder, Jonah
silt/clay content
tubes and excavation pits
crab
III. Homogeneous pebbles-
flat; worm or amphipod
common to abundant -
seastars, sculpin,
and cobbles covered
with sandy sediment;
tubes and excavation pits
solitary and
colonial hydroids;
Ocean Pout, cunner,
occasional lobster,
occasional exposed
finger sponges;
crabs and scallops
rocks
anemones; cerianthids
IV. Homogeneous pebbles,
rocky
sparse to common
abundant winter
cobbles some boulders
finger sponges,
flounder; crabs,
covered with sediment
anemones, tunicates,
scallops. Lobsters,
high silt/clay content
some solitary and
colonial hydroids
seastars, sculpin,
cunner
V. Heterogeneous muddy
flat areas with worm or
restricted to rocks;
winter flounder,
patches with high silt/
amphipod tubes and
finger sponges,
lobster, crabs,
clay content inter-
excavation pits inter—
colonial hydroids,
scallops
spersed with areas of
spersed with rocky areas
tunicates
cobbles, pebbles and
some boulders
VI. Heterogeneous flat
flat areas with worm or
restricted rocky
winter flounder,
areas with sandy
amphipod tubes and excava-
areas; colonial and
lobster, crabs,
sediment Interspersed
tion pits interspersed with
sessile hydroids;
scallops, seastars,
with areas of pebbles,
rocky areas
finger sponges
cunner, sculpin
cobbles and some
anemones
boulders
Data Source: MWRA, STFP, V,
0, 1987

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Lovell
2
O Gogss
Island
p o
S
c
S
Green Is.
Calf
Is.
7
il
•0
0
The Graves
0
zJ
S
(4 )
£
.
I
LEGEND
0
IV HOMOGENEOUS PEBBLES AND
COBBLES COVERED WITH
SILTY SEDIMENT
V HETEROGENEOUS WITH AREAS OF
OF HIGH SILT/CLAY CONTENT
INTERSPERSED WITH AREAS OF
COBBLES AND PEBBLES
VI HETEROGENEOUS WITH AREAS OF
SAND INTERSPERSED WITH AREAS
OF COBBLES AND PEBBLES
DATA SOURCE: MWRA, STFP, V. 0, 1987
/
/
MAIDEN
EVEREIT / \
REVERE
NAUTICAL MILES
Deer
Island
HOMOGENEOUS SOFT BOTTOM
WITH HIGH SILT/CLAY
CONTENT
II HOMOGENEOUS SOFT BOTTOM
WITH LOW SILT/CLAY CONTENT
Bay
Bay
III HOMOGENEOUS PEBBLES AND
COBBLES COVERED WITH
SANDY SEDIMENT
Bumkjn
Island C
0
c 2
S
0
FIGURE C.1.b. BOTTOM TYPES IN THE STUDY AREA

-------
magellianicus. Sea stars including Asterias vulgaris and Henricia sanguinolenta
were also common.
At site 5, the sponge fauna was similar to site 3.5 but with a few more species and
at lower densities. Large anthozoan coelenterates were present in low densities.
Bryozoan-hydroid canopy ranged from 20 to 30 percent cover. Polychaetes and
ascidians also covered cobble surfaces. Seastars including Henricia sanguinolenta
and Asterias vulgaris were moderately abundant. This site has fewer motile species
than site 3.5 (MWRA, STFP, V,T, 1987).
C.1.2.2 Benthic Infauna -
The benthic infauna generally inhabit the mud or soft bottom patches in the study
area. This community is generally dominated by polychaetes capable of consuming
particulate organic materials that have accumulated in the bottom.
Evaluation of the most comprehensive data set for the study area (MWRA, STFP V,T,
1987) shows two distinct infaunal communities within the study area. This is
demonstrated by the MWRA clustering of the 1987 data along the site 2 to site 5
transect (Fig. C.1.a). One community appears to be indicative of nearshore
conditions (sites 2 and 2.5) while the other type is more indicative of farshore
conditions (sites L$ and 14.5). This change in infaunal communities is due to
differences in physical and chemical parameters from nearshore to farshore along the
transect. This distinction may not occur throughout Massachusetts Bay, but it has
been documented at the mouth of Boston Harbor and Broad Sound. This could be due to
the deposit of fine material at the Harbor mouth. Table C.1.c summarizes general
trends at nearshore and farshore areas in Massachusetts Bay. The following is a
discussion of these trends.
C.1.2.2.1 Physical and Chemical Conditions. Both bottom type and depth appear to
show a pattern of change with distance from shore in the soft bottom areas in the
study area. The bottom types at nearshore areas (sites 2 and 2.5) tend to consist
mainly of silt and sand while more offshore (sites 14 and 14.5), cobbles and pebbles
are more prevalent. This trend has been observed in both sediment grain size
analyses and REMOTS investigations (Appendix B; MWRA, STFP, V P,Q and R, 1987; MDC,
C-7

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TABLE C. i.e GENERAL CHARACTERIZATION OF NEAR SHORE AND FAR SHORE PARAMETERS IN MASSACHUSETTS BAT
Rottom
Type
Depth
(m)
Water Column
Nutrients
Density of
Organisms
Dominant
Taxa
Infaunal Temporal
Patterns
Evidence
of Stress
Near Shore
Sand and silt
Shallower
Higher
Not significantly
Aricidea,
Total densities decline
Elevated metal and PAH
(Sites 2,
2.5)
prevalent
(22-26)
different from
far shore
Cirratulids,
Spionids
by end of suniner
concentrations; higher
abundance of oppor-
tunistic species
Far Shore
Cobbles and
Deeper
Lower
Not significantly
Splonids,
Total densities decline
None
(Sites H,
1 1.5)
pebbles
prevalent
(28-32)
dIfferent from
near shore
Syllids,
Amphipods
by end of suniner

-------
19814). Depth also varies with distance from shore in the area of Massachusetts Bay
under evaluation; depths ranged from 22 meters nearshore to 32 meters offshore.
Sediment chemical constituents are variable in the study area; however, there does
appear to be a general trend of higher PAHs, and some metals concentrations in soft
bottom areas nearshore than offshore. Specifically at MWRA site 2.5, PAH
concentrations were at least ten times higher than the offshore sites. Metal
concentrations including chromium, copper, and magnesium, were also elevated at this
site (Appendix B; MWRA, STFP, V,S, 1987). The source of these elevated levels may
be the existing wastewater discharges in Boston Habor. -
Water column chemistry also shows a pattern of change with increasing distance from
shore. In general, nutrient levels are higher nearer to shore than offshore (MWRA,
STFP, V,Y, 1987; MDC, 19814; Parker, 19714).
C.1.2.2.2 Infaunal Species Composition. Spionid polychaetes are the dominant
infaunal taxon throughout the study area (MWRA, STFP, V,T, 1987; MDC, 19814; NEA,
1976). This taxon is abundant in a range of sediment types and depths in
Massachusetts Bay. The spionids are sedentary worms generally characterized by a
pair of elongate palpi used to sweep the surface of the substratum and bottom waters
for food (Gosner, 1971; Levin, 1981; Dauer et al., 1981).
While spionids occur throughout the study area, some differences do exist between
other taxa in nearshore areas (sites 2 and 2.5) and farshore areas (sites LI and
1 1.5). This was especially evident in the extensive 1987 survey (Table C.1.d).
Cirratulid, capitellid, and aricidiad polychate worms and oligochaete worms are
relatively abundant nearshore while offshore these taxon represent only a very small
portion of the community. Maldanid and syllid polychates, axnphipods and bivalves
occur in relatively high numbers offshore and in very low numbers nearshore (MWRA,
STFP, V,T, 1987).
Both species diversity and total number of species (as determined by MWRA, STFP, V,
T, 1987) appear to increase from nearshore to farshore areas. Table C.1.e
summarizes these parameters.
C-9

-------
TA8LE C.t.d PERCENT TOTAL FAUNA DY CRUISE FOR DOHINMT SPECIES AT 1987 MVRA SITES’
Phyllum
Subphyllum
SITE
2
SITE
2.5
SITE
Ii
SITE 11.5
Class Dominant species
Family
CRUISE1 CIWTSE2 CRUISE3
CRUISE1 CRUISE2 CRUISE3
CRUISE1 CRUISE2 CRUISE3
CRUISE1 CRUISE2 CRUISE3
ANNELI DA
Polychacta
C p1tcIIId e Nediomastus cal,forniens,c “ 3.3 “ 9.2 8.2 6.8 5.3 “ 3.7 UI 3)1
Clrratulidae Tharyx acutus 22.1 10.3 7.4 9.5 8.4 5.7 “ “ “ “
Tharyx annulosus “ “_ “ “ “ 3.5 I I I I UI II UI I I
>22 >10 >10 Th >9
Maldanidae Euclymeme sp. A I I I I I I I I PU I I I I II UP PU PU UP
Maldanidae app. juvenile “ I I I I PP I I I I “ 10.2 ‘ 3.1 11.2 II
>10 >3
Lumbrlneridae Lumbrlnerls lmpatiens “ 11.0 1 1 •
Ninoe nigripes 1 ..1.. ‘
Orblniidae Leitoscoioplos acutus “ ‘ 11.11 5.2 “
Paraonldae Arid vies catherinae 27.7 35.6 33.5 10.7 8.6 10.6 ‘ “ U’
Phyllodocidae Plyliodoce sucosa • 11.3 * 1 ‘
Spionldae Poiydora quadriiobata II ‘ • 4.2
Polydora socialis “ ‘ “ ‘ •I 7.6 1 1 11.7 7.11 UI
Prionosplo steenstrupi 19.7 21.3 17.9 34.1 35.6 311.11 21.3 211.2 29.1 21.5 7.6 33.7
Spio limicoia “ “ “ ‘ 11.5 6.0 “ 3.7 “ “ “ I I.?
UP UP PU PP PU UP PU II PP
Spiophanes bombyx ‘ •
>20 T
____________________________________________________________ continued
Species comprising more than three percent of the sample are considered dominant.
Species represents less than three percent of the total fauna or are not present.

-------
TABLE C.1.d PERCENT TOTAL FAUNA BY CRUISE FOR DOHINANT SPECIES AT 1987 HWRA SITI ’ (Continued)
Phyllum
Subphyllum
Class
Family
I)omtnant species
CRUISE1
SITE 2
CRUISE2
CRUISE3
CRUISEI
SITE 2.5
CRUISE2
CRUISE3
CRUISE1
SITE II
CRUISE2
CRUISE3
CRUISEI
SITE 11.5
CRLJISE2 CRUISE3
Syllldae
Exogone hebes
txogo, , verugera
PP
‘
I II
Pu
PP
PP
PP
PP
- PP
PP
PP
PP
17.6
18
PU
11.7
>12
PP
15.6
16
3•9
15.7
>20
PU
18.8
>29
PP
>10
Oil gochaeta
Tubiflcidae
Tubiticoides apectinatus
11.7
>12
fl
6.2
>6
PP
I I I
PP
PP
PP
PP
PP
PP
PP
ARTHROPODA
Hal acostraca
Amphipoda
Corophium crassicorne
teptocheirus pinquis
Photis poliex
Uncioia irrorata
PU

“

PP

‘
3 3

>3
P
P U

PP

PU

PP

3.11

PP
11.9

PP
11.1
51i
‘
3.0
UP
12
3.2
PU
.J. !
>7
PP

) 13
pp

UP
11.7
• •5•
HOLLUSCA
Bivalvia
Astarte undata
creneiia spp. Juvenile
“
“
“
PP
PP
UP
P
j 4
J4
‘P
I i
j
>12
3.8
10.11
>111
3.1
11.0
>7
Species comprising three percent or more of the sample are considered dominant.
Species represents less than three percent of the total fauna or are not present.

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TABLE C.1.e BENTHIC COMMUNITY PARAMETERS FOR EACH MWRA SITE SAMPLED
TEMPORALLY, ALL REPLICATES COMBINED
Site
Total
Number of
Species
Shannon-
Wiener
Diversity
2
97
3.16
2.5
118
3.5 14
11
157
‘4.23
14.5
176 -
‘4.30
Source: MWRA, STFP, V,T, 1987
C.1.2.2.3 Species Densities. Total densities of infaunal organisms are
statistically similar throughout the study area (Table C.1.f). Densities also
appear to be consistent over several years at the same time of year (MWRA, STFP V,
T, 1987; MDC, 19811). Although total densities are spatially consistent throughout
the study area, densities of individual species differ significantly from nearshore
to farshore as indicated in the 1987 survey. The results of an Analysis of Variance
(ANOVA; SPSS, 1986) on the 1987 survey data (Table C.1.g) show the densities of
Aricidea catherinae are significantly higher nearshore (sites 2 and 2.5) than
offshore (sites 14 and 14.5) while the density of Exogene verugera arid Eucymene sp.
are generally significantly higher offshore than nearshore.
C.1.2.2. ’ 4 Temporal Patterns. The information on infaunal benthic communities in
the study area and Massachusetts Bay in general is only available from spring and
summer (MWRA, STFP, V,T, 1987; MDC, 19814; NEA, 1976). Although no real changes in
sediment type or species composition appear to occur throughout the spring and
summer, densities of organisms apparently decline between spring and summer. This
decline appears to be the result of changes in densities of dominant species.
Nearshore (sites 2 and 2.5), the density of the dominant species Aricidea
catherinae, Prionospio steenstrupi , and Tharyx acutus declined gradually throughout
the summer in 1987. Offshore (sites 14 and 14.5), the dominant species Prionospio
C- 12

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TABLE C. 1. F RESULTS OF ONE-WAY AN0VA TO COMPARE LOGe DENSITIES OBTAINED
DURING THREE CRUISES FOR FIVE MASSACHUSETTS BAY STATIONS
Mean Density/M 2
Cruise Station (0.3 mm ‘ 0.5mm fractIons) SD
Schef Fe
F Ratio F-Test
1 2 52,1117 21,1165 11.7 1 176*** 2, 2.5, 11, 11.5 >3
2.5 57,850 6,726
1 1 39,629 13,507
‘1.5 117,279 17,520
3 16,229 10,8111
2 2 39,371 15,822 20.2173*** 2,2.5, 4, 11.5 >3
2.5 115,263 6,830
I I 49,788 12,669
11.5 52,1163 17,073
3 16,067 1,71111
3 2 36,000 12,901 1 1l.9052** 2,2.5 >3
2.5 311,308 5,256
I I 23,583 9,396
4.5 31,329 12,323
3 15,900 6,011
* P(0.05
‘a
**0
Data Source: MWRA, STFP, V, T, 1987

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TABLE C. 1 .g RESULTS OF ONE-WAY ANOVA TO COMPARE LOGe DENSITIES OF FOUR DOMINANT SPECIES
AT F(XJR SELECTED MASSACHUSETI’S BAY STATIONS SAMPLED OVER THREE CRUISES
Mean
Species Cruise Station (0.3 +
Dens ity/M 2
0.5mm Fractions) SD
Schef Fe
F Ratio F-Test
Aricidea 1 2 14,350 7,662 26,7409*** 2, 2.5>4, 4.5
catherinae 2.5 6,138 1,531
LI 1,325 1,884
346 426
2 2 14,333 9,5 1 14 36.90114 ” ’ 2, 2.5>4, 4.5
2.5 3,896 1,519
4 420 800
4.5 155 172
3 2 11,908 3,1154 106.8 953*** 2, 2.5>4.5
2.5 3,638 1,145 2, 2.5>4.5
4 33 14 2>2.5
4.5 325 235
Suclymene 1 2 50 NA 1.1127 NS
sp. A 2.5 675 NA
4 1,046 653
4.5 996 1,221
2 2 25 NA 4.4198’ 4>2
2.5 -- --
4 2,005 1,731
4.5 721 270
________________________________________________continued_________________
* P<0.05
** P<0.01
P<0.001
NA Not applicable.
NS No significant difference.

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TABLE C. 1 .g (Continued). RESULTS OF ONE-WAY ANOVA TO COMPARE LOGe DENSITIES OF FOUR DOMINANT SPECIES
AT FOUR SELECTED MASSACHUSI!rIS BAY STATIONS SAMPLED OVER THREE CRUISES
Mean
Species Cruise Station (0.3 +
Density/M 2 SchefTe
0.5mm Fractions) SD F Ratio F—Test
Euclymene 3 2 -- NA .1822 MS
sp.A 2.5 -- NA
1 1 725 839
11.5 188 110
Exogone 1 2 25 NA 20.5331*** I I, 11.5)2, 2.5
verugera 2.5 788 1,831
1$ 6,7011 2,580
7,121 11,950
3 858 1,252
.11 2 2 25 NA 27.1 1053*** I I, 11.5>2, 2.5
2.5 50 0
I I 5,688 14, 1 136
9,551 1 11,11118
3 2 33 lii 78.6313*** Ii, 11.5>2, 2.5
2.5 liii 38
4 3,525 2,212
115 2,833 1,633
_________________________________ continued
* P
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TABLE C. 1 .g (Continued). RESULTS OF ONE-WAY ANOVA TO COMPARE LOGe DENSITIES OF FOUR DOMINANT SPECIES
AT FOUR SELECTED MASSACHUStTJS BAY STATIONS SAMPLED OVER THREE CRUISES
Species
Cruise
Station
Mean
(0.3 +
Dens ity/M 2
0.5mm Fractions)
SD
Scheffe
F Ratio
F-Test
Prionopsio
Steenstrupi
1
2
2.5
4
4.5
3
10,213
19,596
8,150
9,738
256
2,774
1,914
5,799
14,414
332
8.3877 **
2.5>2,
I4,14 5
2
2
2.5
4
4.5
3
8,354
16,088
11,800
3,850
360
3,1499
2,433
10,210
3,1402
2014
5.1018”
•
2.5>14.5
3
2
2.5
14
1 1.5
3
114,350
11,796
6,588
10,375
100
7,662
2,790
6,421
14,031
71 1
2.5517”
NS
* - P<0.05
** P<0.01
P<0.001
NA Not applicable.
NS No significant difference.
Data Source: MWRA, STFP V, T, 1987
-------
steenstrupi and zxogone verugera also declined In density from spring to summer
(MWRA, STFP, V,T, 1987). The decline in densities of these dominant species are
likely the results of two factors. One Is reduced recruitment as evidenced by large
declines in smaller animals. The other factor appears to be mortality of all size
classes, perhaps due to predation.
C.1.2.2.5 Evidence of Stress. The relatively high levels of PAHs and certain
metals in nearshore areas as discussed previously may be indicative of a somewhat
stressed benthic environment in this area. Species known to be opportunistic or
pollution tolerant (Pearson and Rosenberg, 1978) are not highly dominant in the
study area as a whole; however, two pollution tolerant taxa, the po]ychaete,
Kediomastus californiensis and oligochaete worms are relatively common nearshore
(MWRA, STFP, V,T, 1987). This may indicate that the nearshore area may be somewhat
stressed. Also, pollution sensitive species such as amphipods (Maughan, 1986;
Pearce, 1972; Bottom, 1979; Steimle, 1982) are more abundant offshore than nearshore
indicating that conditions offshore may be relatively less stressed than nearshore.
C.1.2.3 Benthic Co nunities In Boston Harbor
The benthic communities in Boston Harbor generally consist of two distinct
communities. One type of community inhabits the southern portion of the harbor
while the other type of community occurs In the northern portion of the Harbor. The
community in the southern part of the Harbor (near Nut Island) is generally
characterized by moderately dense communities with a high number of taxa, high
eveness and diversity and with relatively high numbers of pollution sensitive
aznphlpods (MDC, 1981!).
The northern part of the Harbor in the vicinity of Deer Island and west of
Deer Island is characterized by a benthic community that appears to be more impacted
by pollution than the southern community. The benthic community at Deer Island
Flats (west of Deer Island) and the mouth of the Inner Harbor exhibits several
ecological community indices which are indicative of a stressed macrobenthic
community, including low species diversity, dominance by a few opportunistic species
and few amphipods (MDC, 19814; Rowe et al., 1972).
C-li
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C.1.3 PLANKTON
This section presents information on both phytoplankton and zooplankton communities
as well as primary production and nutrients in the study area.
C.1.3.1 Pbytoplankton
Several studies on phytoplankton and primary productivity have been conducted in the
the Gulf of Maine and its coastal embaynient, Massachusetts Bay. The Gulf of Maine
itself is bounded on the west by the New England coastline and to the northeast by
the Bay of Fundy and Nova Scotia. Access to the Atlantic Ocean from the Gulf of
Maine is through the northeast channel which lies between Browns Bank and Georges
Bank. The southwestern boundary of the Gulf of Maine is the Great South Channel
(Edwards, 1983; Figure C.1.c). The following is a description of general
phytoplankton distribution in the Gulf of Maine and Massachusetts Bay.
C.1.3.1.2 General. Marshall and Cohn (1983) summarized several years of National
Marine Fishery Service (NMFS) Marine Monitoring Assessment Program (MARMAP)
phytoplankton cruises in the northeastern continential shelf. Phytoplankton
populations over the northeastern shelf where found to consist of a diverse
assemblage of species that differ seasonally in composition across the shelf. The
most abundant phytoplankters can be divided into three major groups: the small-
sized diatoms, the phytoflagellates, and the nannoplankton (mainly 2 to 5 u size
range). The small diatoms including Skeletonema costatum, Asterionella glacialis,
LeptocylifldrUs danicus and Rhizosolenia delicatulum, were seasonally associated
with the spring and fall bloom periods, with highest concentrations close to large
estuary systems. According to Marshall and Cohn (198LU, lower diatom densities
generally occured seaward with patches of’ high densities associated with Georges
Bank. The phytoflagellates occured in high numbers in late spring and summer.
These phytoflagellates generally consisted of dinoflagellates, coccolithophorids,
cryptomonads and euglenoids. The dinoflagellates were distributed over the entire
shelf and occured in highest densities nearshore and during summer. The
coccolithophores also occurred over the entire shelf but were more abundant in the
outer shelf. The densities of the euglenoids were generally lower than the other
phytoflagellate components; however, they were frequently found over the shelf in
C-i 8
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FIGURE C.1.c. PRINCIPLE FEATURES OF THE NORTHWEST
ATLANTIC CONTINENTAL SHELF
I
%_. I —
—‘ (BROWNS
_._, - SANK
NORTHEAST
I — .
SA RGASSO
—— lOOm
200m
C- 19
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late spring to early summer. The nannoplankton component of the phytoplankton was
generally non-flagellate. This community is generally abundant and widespread over
the continential shelf. (Marshall and Cohn, 1984).
Review of NMFS MARMAF chlorophyll a data collected at stations throughout the
northeastern continental shelf from 1977 to 1985 reveals a pattern of decreasing
chlorophyll a concentration with increasing distance from shore. Chlorophyll a
concentration averaged 1.2 mg/rn 3 at one station within Massachusetts Bay over the
sampling period while at a station approximately 10.8 nautical miles east of
Massachusetts Bay, chlorophyll a concentration averaged 1.03 mg/rn 3 .
Phytoplankton communities of low densities (approximately 50,000 cells per liter)
generally dominated by dinoflagellates or diatoms occur from November to February in
the Gulf of Maine and Massachusetts Bay (TRIGOM, 1974). From February to June
various diatoms bloom. Spring blooms in Massachusetts Bay generally occur by
April. These blooms result in densities of over a million cells per liter. Spring
diatom blooms of Chaetocheros spp. occur subsequent to Thalassiosira spp. blooms and
continue for one to four weeks. Summer blooms of small-sized coccolithophores are
common in open basins of the Gulf of Maine while the diatoms skeletonema spp. and
Rhizosolenia spp. may bloom in early fall in the more coastal areas. Secondary late
summer and fall blooms of some neritic diatoms occur in Massachusetts Bay.
Specifically there is a continuous bloom of the diatom Skeletonema costatum, from
the last week of August to the end of October (TRIGOM, 1974).
C.1.3.1.3 Massachusetts Bay Studies. Parker (1974) conducted a
phytoplankton/primary productivity study from March 1973 through June 1974 at five
stations in Massachusetts Bay as part of the New England Offshore Mining
Environmental Study (NOMES). All of the stations were located in the vicinity of
the present study area (Figure C.1.d). Similar to the general pattern described
above, this study found the maximum phytoplankton densities to occur during spring
(March—May) and fall (September—October) diatom bloom periods with biomass maximums
of 6 and 3.6 gC/m 2 respectively. MWRA (STFP V,Z, 1987) also observed a diatom bloom
in late summer. In the Parker study, primary productivity was highest during the
spring bloom period in March (1170 mg C/m 2 /day) and also increased during the fall
bloom (to 8140 mg C/m 2 /day). Generally the first part of each biomodal bloom was
more productive than the second.
C-20
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SOURCE: PARKER. 1974
MWRA, STFP, V, Z, 1987
I’ .)
The Graves
Green Is.
GG’°
Island
Biamkln
Island
Slate
Island
FIGURE C.1.d. MASSACHUSETTS BAY PHYTOPLANKTON STATION LOCATIONS
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Parker (197L ) also observed a marked offshore trend of’ decreasing primary
productivity and chlorophyll a concentration associated with a parallel decline in
nutrient concentration. Average annual primary productivity near shore was
estimated to be approximately 3140 g C/m 2 /year (Parker’s Station C2). Offshore
primary productivity was estimated as low as 220 g C/m 2 /year (Parker’s Station A 1 4;
Fig.C.1.d). ’ This trend of decreasing primary production, chlorophyll a
concentration and nutrients with increasing distance from shore was also observed in
the summer 1987 MWRA survey (Figures C.1.e to C.1.h).
Parker found that variation in specific productivity rates and variation in
chlorophyll a content were directly related to observations made on nitrogen-
deficient cultures of marine phytoplankton, suggesting that nutrient availability
(specifically nitrogen) had a strong influence on the initiation and duration of the
major bloom periods. According to Parker (19714), nutrient addition from land
drainage into the inner harbor area is transported into Massachusetts Bay and
appears to be the most significant variable that contributes to spatial differences
in primary’ productivity. The 1987 survey confirmed that nitrogen is the limiting
nutrient in these waters, based on production levels and nitrogen-to-phosphorus
ratios.
Significant chlorophyll a concentrations occurred in deep water below the euphotic
zone (3 percent isolume) and stratified surface layer during the 1987 survey.
Nannoplankton (the (10 i size fraction) accounted generally for more than 70 percent
of the total chlorophyll concentration. During the 1987 survey, “surges” of’
nitrogen and phosphorus which coincided with incursions of colder water occurred
twice. (MWRA, STFP, V,Y and Z, 1987). The origins of these surges are unknown.
The mean carbon growth rates during the 1987 survey were similar at all stations,
(Fig. C.1.d) approximately 0.5 g C/day, corresponding to a mean population carbon
doubling time of <18 hours. This indicates that the phytoplankton communities at
all the sites were in a similar physiological state suggesting that nearshore sites
(P1 and P3) were no more stress than offshore sites (P2). These phytoplankton
communities appear to have similar species composition at all sites but with higher
densities and production rates near the harbor.
C-22
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180 —
LEGEND
170 - _________
I I TOTAL PHYTOPLANKTON
160 - _________
NANNOPLANKTON
150 —
140 —
130 —
120 —
110 -
100—
21
-J 80.
>.
X
r\)
LU 70-
0
-J
50:
_ -
STATION P1 P2 P3 P1 P2 P3 P1 P2 P3 P1 P2 P3 P1 P2 P3 P1 P2 P3 P1 P2 P3
DATE 15-JUL-87 21-JUL-87 28-JUL-87 05-AUG-87 12-AUG-87 25-AUG-87 08-SEP-87
DATA SOURCE MWRA STFP. V. Z. 1987
F1C(JR E C. I.e.. INTEGR ATF.D WATER COLUMN CIII.OROPIIYLL CONCENTRATIONS
AT ‘FIII{,EE STATIONS FOR SEVEN SURVEYS
-------
140 —
LEGEND
130- 1 1 TOTALPHYTOPLANKTON
120 ________ NANNOPLANKTON
110-
100 -
90 -
80 -
N
70-
c _ i
0
0

ft L iL - ]jy
STATION P1 P2 P3 P1 P2 P3 P1 P2 P3 P1 P2 P3 P1 P2 P3 P1 P2 P3 P1 P2 P3
DATE 15-JUL-87 21-JUL-87 28-JUL.87 O5AUG-87 12•AUG-87 25-AUG-87 08-SEP-87
DATA SOURCE MWRA STEP. V. Z. 1987
FH;UR I C.i .1. JNTR.EGR ATI U FUPIIOTJC ZONI CHLOROPHYLL CONCENTRATIONS
AT TIII{,EE STATIONS FOR. SEVEN SURVEYS
-------
7—
LEGEND
6.5- ________ AMMONIA
I I NITRATE
6 N\\”.\1 PHOSPHATE
SILICATE
5 5—
5—
45-.
Ui
I-.
-J
I
j- c cc-L -J
STATION P1 P2 P3 P1 P2 P3 P1 P2 P3 P1 P2 P3 P1 P2 P3 P1 P2 P3 P1 P2 P3
DATE 15-JUL.87 21-JUL.87 28-JUL.87 05-AUG-87 12.AUG.87 25-AUG-87 08 SEP.87
DATA SOURCE MWRA. STFP. V. Z. 1987
FiGURE C.I.g. MEAN NUTRIENT CONCENTRATIONS AT THREE STATIONS
FOR SEVEN SURVEYS
-------
6
4
0
I N 0
r )
0 ’ — 4
U)
O
I
0
3
STATION
DATE 15-JUL-87
DATA SOURCE MWRA. STFP, V. Z, 1987
ii;tJin C.! .h. INTECR ATI U WA’I’FR COI IJMN PRIMARY PROI)UCTR)IN RATES
Al’ ‘Ill II I’ !• S’IA’l’I I-OR SEVEN St I H VEYS
5
4
2
0
21-JUL-87 28-JUL-87 05-AUG-87 12-AUG-87 25-AUG-87
08-SEP-87
-------
Blooms of nuisance algae have been known to occur in Massachusetts Bay.
Specifically, the filainentous brown algae, Pilayella littoralis, periodically blooms
and is washed ashore in Nahant Bay and decomposes in the intertidal zone. (Quinlan
et al., 1983; Wilce and Quinlin, 19811).
In sI1Tmn ry, the principal components of the phytoplankton communities in the
Massachusetts Bay surveys reflect normal occurrence of the summer flora of New
England temperature coastal waters with flagellates being abundant throughout the
summer and diatom blooms occurring in spring and fall (Marshal and Cohn, 19811; and
Marshal, 198 1 1a; Marshall, 19811b, Marshall, 1978; NMFS, MARMAP 1978-1985). Trends of
decreasing productivity, chlorophyll a concentration and phytoplankton density with
increasing distance from shore occur in Massachusetts Bay. The limiting nutrient in
phytoplankton production in the study area is nitrogen.
C.1.3.2 Zooplankton
C.1.3.2.1 General. In general, little site specific information is available on
zooplankton in the study area. It is also not likely that zooplankton will be
directly impacted from the project. The zooplankton, therefore, are discussed only
briefly in this section.
Zooplankton comprise the animal component of the plankton and may be divided into
two major groups, the neritic and oceanic zooplankton. The neritic zooplankton
exist along the coast and seaward to about 100 meters in depth. Euryhalene neritic
zooplankton are those restricted to estuaries. The zooplankton occurring in the
study area are generally neritic (TRIGOM, 19711).
The characteristic species of the neritic zooplankton in the Gulf of Maine include
the copepods Temora longicornis, Eurytomora herdmori, Centropages hamantus,
Pseudocalanus minutus and Miscrostella norvegica, the nauplii of cirripedes (larvae
of barnacles; and the cladocerans, Podon spp. and Evadne nordmanni (TRIGOM, 19711;
Bigelow, 1926). The oceanic forms of both arctic and temperate offshore areas also
occasionally broadly overlap the neritic community. The euryhaline estuarine
zooplankton component of the neritic zooplankton are comprised largely of
meroplankton (those species that are pelagic for only a portion of their life, i.e.
C-27
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larval forms) and tychoplankton (those species which are normally bottom dwelling
and are either swept up or swim into the water column) as well as a typical
holoplankton component. Most benthic infaunal species have planktonic larvae and
during certain seasons comprise a significant portion of the zooplankton
community. The most abundant copepod of the holoplankton is Acartia spp. Other
common copepods include Tortanus disdatus and Oithona spp.. Although no specific
data is available on trends in zooplankton densities, it is likely that the relative
density of zooplankton reflect the relative densities of their food source, the
phytoplankton. Hence, zooplankton densities likely decrease with Increasing
distance from shore In Massachusetts Bay.
C.1.3.2.2 Ichthyoplankton. Lux and Kelly (1978) summarized NMFS ichthyoplankton
data collected in Massachusetts Bay from 1976 to 1977. Their results show that the
abundance of fish eggs and larvae in Massachusetts was low in late winter, increased
to a peak in June and declined considerably by August. This appears to be the
typical seasonal pattern for ichthyoplankton in Massachusetts and Cape Cod Bays
(Anderson and McGrath, 1976). Table C.1.h presents a summary of the seasonal
occurence of eggs and/or larvae of the common spawners in Massachusetts Bay.
C.1.3.3 Plankton Communities in Boston Harbor
In general, based on a review of several plankton studies in Boston Harbor both the
phytoplankton and zooplankton communities appear to be uniform throughout Boston
Harbor. The plankton community composition appears generally similar to that of’
Massachusetts Bay (MDC, 19814).
C.1.lI FISH
Quantitative information on fish communities In Massachusetts Bay is somewhat
limited and not site specific; however, a wide variety of fish investigations have
been conducted in the Gulf of Maine and Massachusetts Bay. Most work has been
conducted by NMFS and Massachusetts Division of Marine Fisheries (DMF). NMFS is
involved in such programs as ground fish surveys, MARMAP, and population dynamics
• studies of commercially important species (TRIGOM, 19711). Understanding the
population dynamics of fish in the Gulf of Maine as well as Massachusetts Bay is
Important because of the cosmopolitan and migratory nature of fish. The
distribution of fish in Massachusetts Bay is highly influenced by the Gulf of
C-28
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TABLE C. I .h BEASOIIRL OO 1RBE OR TUE IUEB aEU N POMD OF FISH S I!) MD/OR LABVAE (L) ID flIFI BY IFS Il ORPE O M D MSSASHUS B MT
Inshore
Of C ahore
Inehore
Inehore
Of fehore
Off ahore
Inahore
Inahore
Inshore
March
March—April
April
April
Nay
Nay
June
August
October
Comeon Name Specie. 1977
1976
1976
1977
1976
1977
1977
1976
1976
Atlantic Menhaden Brevoortla tVrannus K B L B L B I.
Atlantic Herring Clupea harengus harengus 1. 1. L L
Cuek Brosme broaae B L
Pourbeerd Rockling Hnchelyopua cimbrius B B B B B B L B L B I.
Atlantic Cod Cadus morhua B L B 1. 8 L B L B L B L B 1. B B
Haddock Ilelanograwmus aeglefinus B B L B L
Silver Hake Merlucclus billnearis B I. B I . B L
Hakea Urophycia app. 1. 8 1. B L B L B I.
Tautog Tautoga onitla L L L L
Cunner Thutogolabrua adapersus L L L L
Radiated Shanny Ulvaria aubbifurcata L 1. L L L L I.
‘U
.Q Ginnet Phollq gwinellus L L L L L
Band Lance 9odgtes app. L L L L L L L L L
Atlantic Mackerel Scomber scombrus B B L B L B L
Butterfiah Peprllu. triacanthua B B L I.
Searobin Prlonotua ai,i,. B B L
Sculpin . Ngorocephalus app. I. L L L L
Sea .naile Liparia app. I. 1. L L I. L L
Windowpane Scuphthalmus aquosus B L B B L L
Witch Flounder 61 yptocephal us cynoglossus B B 1. B B B 1. 8 L 1.
American Plaice Rippogiossoides platessoides B I. B L B L B L B L B L B L
Yellowtail Flounder f.ijranda ferruqinea B B B L B B L B I. B L B
Winter Flounder Pscudopieuronectes aaericanua B 1. B L B L 1. B I.
Source of date (Table number .) 16 17 25 6—9 18-23 2—5 24—25 26—29 10—lI 12—15
I. While the egg . of thi. species are demersal they sometimes were caught in plankton tow, in shallow water where current. carried them o t t bottom.
Sources Lu. and Belly. 1982
-------
Maine. The following is a general description of fish populations in the Gulf of
Maine and Massachusetts Bay.
C.1.lI.1 General
Fish species generally migrate in response to seasonal and local variations in
temperature. Seasonal temperature variations therefore have the greatest influence
on the seasonal abundance, distribution and species composition of the fish fauna in
the study area. Seasonal temperature conditions that influence the fish populations
in the study area include the col d water barrier at Cape Cod which separates the
Gulf of Maine from the Mid-Atlantic Bight from June to September by means of a sharp
temperature differential. During the rest of the year, a temperature continuity
exists between the areas. The Gulf of Maine waters are relatively homothermal
seasonally while the Mid—Atlantic Bight waters are heterothermal (TRIGOM, 19711).
The Mid-Atlantic Bight contains very few permanent residents and is composed of
continuously shifting populations, while the Gulf of Maine contains mostly endemic
species with some seasonal change in species composition. In the Mid-Atlantic
Bight, a population of southern migratory fishes follows the northern dispersal of
isotherms to Cape Cod (Fig C.1.i; Table C.1.i; TRIGOM, 19711). Many of these species
including spiny dogfish, American shad, hakes and mackerel, enter the Gulf of Maine
and Massachusetts Bay and remain there throughout the summer. In winter, they
migrate either south or to the warmer continental slope waters in the Gulf of
Maine. The Mid-Atlantic Bight populations are “replaced” by a limited seasonal
diffusion of a few species that are endemic to the Gulf of Maine, but which “spill
over” to the Mid-Atlantic Bight in winter (TRIGOM, 19711).
During winter, many summer migratory species move to the warm slope water off
southern New England. These species include red hake (Urophycis chuss), silver hake
(Kerluccius bilinearis), soup (stenotomus chrysops), butterf’ish (Peprilus
triacanthus), summer flounder (Paralichthys dentatus), and goosefish (lophius
americanus) as well as some less common species. The winter component of fishes
migrating from the north and east consist of Atlantic cod (Gadus morhua), yellowtail
flounder (Limanda ferruginea) and longhorn sculpin (Myoxocephalus octodecemspinosus)
(TRIGOM, 19711). Generally, the fishes of the summer component are most abundant on
C-30
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FICtIUTE C.1.i. GENERA I A MOVEMENT OF MIGRATORY FISH SPECIES IN TIlE
NOItTIIWESTERN ATLANTIC OCEAN.
y
w
-------
TABLE C. 1.1 SEASONAL MIGRATION CHARACTERISTICS
OF SOME IMPORTANT FISH SPECIES
Common Name Species Name
I. Southern summer migrants (north to Cape Cod)
Summer flounder Paralichthys dentatus
Scup Stenotomus chrysops
Weakfish Cynoscion regalis
Kingfish Ken ticirrhus saxatilis
Mullets Kugil sp
Black seabass Centropristes striata
Filefishes Aluterus sp., Konacanthus sp.
Pompanos Caranx hippos and other species
Northern puffer .Sphaeroides maculatus
II. Northern summer migrants (north into the Gulf of Maine)
Spiny dogfish squalus acanthias
Silver hake Nerluccius bilinearis
Red hake Urophycis chuss
White hake Urophycis tenuis
American shad Alosa sapidissima
Striped bass Korone saxatilis
Menhaden Brevoortia tyrannus
Bluefish Pomatomus saltatrix
Atlantic mackerel Scomber scombrus
Butterfish Peprilus triacanthus
Bluefin tuna Thunnus thynnus
III. Southern winter dispersal
Atlantic herring Clupea harengus
Atlantic cod Gadus morhua
Pollock Pollachius virens
Source: TRIGOM, 197L1.
C-32
-------
inshore grounds when the water temperature is the same as that in which they were
most abundant offshore.
Generally, almost all non-migratory species exhibit some seasonal movement. Fish
are generally scarce along nearshore areas in the Gulf of Maine in winter. Only sea
raven (Heritripterus americanus) or longhorn sculpin (Myoxocephalus
octodecemspinosus) occur in shallow waters in winter. In March, winter flounder
(Pseudopleuronectes americanus), ocean pout (Macrozoarces americanus), sculpin
(Myoxocephalus spp.) and little skate (Raja e.rinacea) appear nearshore. Later in
the summer, cunners (Tautogolabrus adspersus), alewife (Alosa pseudoharengus) and
lurnpfish (Cyclopterus .iumpus) occur. In the fall the process is reversed (TRIGOM,
1971 1).
Table C.1.j presents information on the life histories of several species occurring
in Massachusetts Bay based on Bigelow and Schroeder (1953); TRIGOM (19711); Grosslein
and Azarovitz (1982).
C.1.14.2 Massachusetts Bay
Information on fish in Massachusetts Bay is available from the NMFS biome program
(Lux and Kelly, 1978; 1982), semi-annual trawl surveys of’ demersal fish, by
Massachusetts Division of Marine Fisheries (MDMF) as well as a limited 1987 MWRA
survey.
NMFS has conducted bottom trawl surveys at least twice a year (spring and fall)
since 19119 in Massachusetts Bay. Table C.1.k presents a summary of seasonal catches
from 196i4 to 1971. A total of 36 species have been collected in these surveys.
Table C.1.l shows the abundance of demersal fish collected by the Massachusetts DMF
in May and September bottom trawls from 1978 through 1986. The depth intervals
reported are within the present study area. Winter flounder (Pseudopleuronectes
americanus) is the most abundant species in all depth intervals in May and remains
the most abundant species in September although actual abundance decreased at all
depths from May to September. Winter flounder in Massachusetts Bay are known to
disperse to deeper water throughout the summer after spawning in Boston Harbor and
C-33
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TAIL! C.l.j SUIIIRIT OP FISH DISTRIBUTION ND LIP! HISTORIRS
Bluefiahea Po.ato.idae
Bluefish Porgstomus saltatrlx
New York Bight, southern New
England, and North Carolina in
summer and Florida in winter.
Within a few .lLea of
shore over most of
their range.
Consume fish (butterfish. round.
herring, sand lance, menhaden
silveralde. mackerel, and anchovy)
end invertebrates (shrimp, squids.
crabs, mysids, and anneild worms).
itterIiaheu Strom.teidae
Butterfish Peprilus triacanthua
Newfoundland to Florida. Most
abundant between Southern New
EngLand and Cape Hatteras.
Eggs and larvae
are pelagic.
May—June
Offshore, 8. to edge
of continental shelf,
waters warmer than 15 C.
Not above Cape God.
Feeds on copepods. small fish,
polychaetes, small Jellyfish,
and gammarid amphipods.
G.didae
Cadus ourhua
Haddock Kolanogrammus
aeqletInls
Found around Iceland, southern
Greenland, and from Baffin Island
to North Carolina. New England
substock — Georges Bank, Gulf of
Maine (North of Provincetown, MA),
and southern New England.
Labrador to Florida.
Summer in Gulf of Maine.
Along continental shelf from
southsrn Nova Scotia to North
Found along the continental shelf
between South Carolina and the
Grand Banks. Most abundant
between Cape Sable, Nova Scotia.
and New York.
Eggs and larvae
peLagic. Seek
bottom at 4 cm.
Eggs and larvae
pelagic.
Not below 90m Eastern
Georges Bank, Browns
Bank, Mass. Bay 3—10
milea off—shore,
lpswich Bay.
Broken bottom of mixed
rock, gravel, mud and
sand. 4—7 C.
Relatively shoal water,
within 100. isobath.
Entire coastal cone
from Long Island to
Sable Island. Sandy
slopes shoaler than
90.. Most important
N & E of Cit’. .).I.
Various invertebrates (brittle
stars, bivalve mollusks, worms,
anChipoda, craha, geatropods,
starfish, sea urchins, sand
dollars, sea cucumbers, and
squid) and occasionally fish.
Primary plankton eaters. Most
important food item is the euphasid
Iteganyctlphoncs norw3gica. Also eat
fish.
Primarily feed on a.phipods.
Also eat fish, squid, shrimp, and
various invertebrates.
Opportunistic and predacious. Diet
consists primarily of Fish, crusta—
ceanq, and q.Iuid.
Western
Atlantic
Common Name Scientific Name Range and Distribution Spawning Type Spawning Time Spawning Areas Feeding
Eggs and larvae
are pelagic.
June—August.
Peak in July.
dfIshea
Atlantic
Cod
Pollock Pollachius virens
Red Hake Urophycis chusa
Frequently feed on benthic inverts—
bratcs: crabs, cla.a, mussels, snd
molluscs. Also eat fish.
Labrador to Florida.
Summer in Gulf of Maine.
Chiefly in winter.
Feb. —May. Peak in
March—April.
Nov.—March. Peak,
late Dec.
Summer.
heavily concen—
June—Sept.
Principally in
July and August.
Silver
Hake
Chiefly region of Mass.
Bay. 27—90.. 6—8 C.
trated fro . the southwestern part
of Georges Bank to Hudson Shelf
Valley). Summer in area betueen
Martha’s Vineyard and Long Island
and on Georges Bank.
Marl uccius
balinearis
Eggs and larvae
peisgic.
Eggs and larvae
pelagic.
Carolina. (Most
Eggs and larvae
pelagic.
-------
TABLE C.I.J SIJIIIAIT OP FISH DISTRIBUTION ND LIFE HISTONIES (Continued)
Eggs and larvae
pelagic.
Dogfish
Sharku
Spiny
Dogfish
Sciaen idas
Weakf lsh Cyr.oacion regal is
Labrador to Florida. Don! vorous.
Gulf of Maine in Summer.
Pro, southern Florida to Eggs buoyant.
Massachusetts Bay to Nova Scotia.
Large estuaries or near
their mouth.. Not
above Cape Cod.
Opportunistic; primarily eat
mackerel, herring, scup and
flatfi.h; one of the few species
that will eat ctenopore..
Frequently prey upon butterfish.
herring., sand lance, silversides,
anchovies, and young veakfish.
Eel Pont. Zoarctdae
Ocean Pout Hacrozoarcea
americanus
Prom Labrador to Delaware Bay.
Most common fro. the southern
portion of the Gulf of St. Lawrence
to New Jersey. Abundant of £ Lang
island in winter and spring.
Newfoundland to North Carolina
(centering between the Gulf of
Maim. and henape3k Bay). Aggregste
on the continental shelf between
Block Island and Cape May in spring.
Sept.—Oct. Rocky bottoms.
Congregate for
spawn! 1 1g.
Spring. Ponds and sluggish
streams. 13—16°C.
Feed primarily on invertebrate.;
sissela, other bivalves, whelks,
periwinkles, brittle stars, sea
urchins, sand doLlars, crabs, and
other crustaceans. Occaeionally eat
fish and fish egg..
Considered chiefly planktivorou..
Feed primarily on euphaualtd.,
.vqids, molluscs, and
chaenognath..
Atlantic
Menhaden
Greenland and Labrador to Cape
Hatteras. Georges Bank in Ipring
and fall.
Brcvoortia tyrannu. Maine to Florida. One of the more
abundant fishe. in the New York
Bight, especially from May to
October.
Shallow coast & banks,
particularly Georges
Bank, less than 90 ..
Rocky—gravelly bottom.
*5—18 C, coastal
water.. Rarely above
Cape Cod.
Feed primarily on chaetognath..
euphausiids, and pteropods.
Blueback
Herring
Alosa aestivalls
Nova Scotia to Florida. Most
abundant south of New England.
Concentrated on the continental
shelf between southern New England
and Cape May in spring and in the
Gulf in Maine in autumn.
Anad romous.
Eggs demersal.
Late spring.
Nearer tidewater than
alewife. 20—23 C.
Principal food items include
cirrepedia and copepods.
Billifiahe. Cyprinodontidae
Mummichog Fundu lus
helerocl itus
Labrador to Florida.
Summer in Gulf of Maine.
Egga, demersal,
adhesive.
Apr! 1—earLy August.
In a few inches of
water, close to shore.
Omnivorous.
White Uropliycis tenuis
Hake
Same as Red Hake.
Squalldae
Sgualus acanthias
Western
Atlantic
Common Name Scientific Name Range and Distribution Spawning Type Spawning Time Spawning Areas Feeding
Summer.
Same as Red Hake. Same as Red Hake.
Young born jut Of fehore wintering
Nov. — Jan. 2nd year. grounds.
May—Oct. Peak
mid—May to Hid—June
C)
I Barring.
Alewife
American
Shad
Clnpedtae
Alosa
pseudoliarengus
Alosa sapidiasima
Egg . laid in
ge latinoue
masses. Larvae
demer.al.
Anat lromous.
Egg. demer.al.
Anadromoua.
Eggs semi—buoyant
not sticky.
Atlantic Clupea harengus
Herring harengus
From the St. Lawrence River,
Canada to ths St. Johns River,
Florida.
Spring or early
summer. 10—13 C.
Sandy or pebbly
shallows.
Egg. adhesive, Sept.—Nov.
demersa 1.
Larvae pelagic.
Egg. and larvae
pelagic.
Feed on zooplankton including large
copepods, myaids, and euphausiid..
May—July and
Sept—Oct.
Omnivorous, subsisting mainly on
unicellular plants.
-------
TASLE C. L.j SIM4ANT OP FISH DISTRIWTION MD LIFR RISI PIIS (Cmitlmued)
Lefteye
Flounders
Summer
Flounder
ligbteye
() Flounders
Winter
Flounder
Pleuronectidse
Paeudop1 u roneceea
amerLcanus
Yellowtail Lirganda t.rruglnea
Flounder
Sand Lances A dyt Use
American Amjaodytea amerlcanua
Sand Lance
Scorptonf ishes Scorpaenidse
Redflsh or Sebastes nwrlnus
Ocean Perch
Western North Atlantic from Black
laland, Labrador to Beaufort,
North Carolina. Gulf of St.
Lawrence in summer. Overvinter
on the continental shelf from Sable
Island Bank to the Chesapeake Bay
region.
Labrador to Chesapeake Bay. Most
abundant in New York Bight, off
New England to Georges Bank, off
the south shore of Nova Scotia
near Sable Island, and on Grand
Bank. Between New York Bight
and Georges Bank and as far
south as Delaware in Bay in spring.
From Cape Hatteras to Hudson Bay
and Greenland.
Island to West Greenland to
southeastern Labrador to
New England.
F.gga develop and
hatch within the
oviduct. Larvae
pelagic.
Sept.—Feb. in a north
to south progression.
Early Sept. for the
Gulf of Maine.
Deep water within 46k. Predominantly eat fish. Will also
of shore, 12—19 C. consume rock crabs, squids.
shrimps, small bivalve molluscs,
small crustaceans and snails.
marine and sand dollars.
Estuaries, bays end
inshore waters,
18—20 C. Not above
Cape Cod.
Both inshore and
offshore. Rocky and
hard ground. 2—9 C.
Prey upon invertebrates, primarily
small crustaceans including
a.phlpods. polychsete worms, and
a few small molluscs.
Predominently copepods. Also feed
upon crustacean larvae, inver-
tebrate eggs. polychsets larvae,
larvaceana. fish eggs, pteropods,
and cirripede larvae.
Eats various invertebrates, espec-
ially crustaceans includIng
syadi euphasid. decnpod shrlmpa. &
small molluscs. Also eats ft h.
From Nova Scotia to Florida.
Western
Atlantic
Common Name Scientific Name Range and Distribution Spawning Type Spawning Time Spawning Areas Feeding
Bothidae
Paral Ichthys dentatus
Sco.brtdae
Scomber scosbrus
Soartd.e
S tenotomus chrysopa
Nackerels
Atlantic
mackerel
Porgies
Scup
Primarily Chesapeake Bay Opportunistic. Feed largely on
to Cape Cod, 9—13 C, calanoid copepode and pteropods.
no spawning grounds.
Primarily found from Cape Hatteras
to Cape Cod.
Occur in significant numbere from
Cape Cod Bay through the Gulf of
Maine. Pro. Cape Hatteras to Nova
Scotia in spring and autumn.
Eggs and larvae
are pelagic.
Eggs and larvae
are pelagic.
Eggs and larvae
are pelagic.
Eggs sink and
adhere (demeraal,
no.ibiioyant).
Larvae have mixed
planktonic-
benthic behavior.
Eggs and larvae
are pelagic.
Eggs-demeraal,
adhesive.
Consume coelenterates. polychaetes,
crustaceans, molluscs, and
quantities of vegetable debris.
Spring—early summer.
Peak May—June.
May—August.
Peak May—mid—July.
Jan.—May.
March—August.
Autumn and early
winter, late Nov.
—late March.
Peak late June to
early July.
In shoal water, 7. in Feed primarily on invertebrates;
backwaters of bays and coelenterates, nemerteans,
ostjarieu ond on polychaetes. cruataceans, molluscc,
Georges Bank at 45.—72.. and ascidiana. Will also consume
SC. Sandy bottom. plant material.
Water 46 to 64 meters
deep. Over sand bottom.
Inshore and off—shore
above 27.. Sandy
bottom.
-------
TAILE C. 1.1 SUIIIAfl OF FISH DISTRIBUTION MID LIVE HISTORIES (Coutisued)
St iverside.
Atlantic
S(lverside
Skates
Little
Skate
Eastern Newfoundlsnd to New Jersey.
Commonly found in Block Island
Sound from November through April
and off New York from September
to Nay.
North Carolina to the southern aide
of the Gulf of St. Lawrence.
Aggregate off eaStern Long Island
during spring.
June—August. Baya and sounds.
Not above Cape Cod.
May—July. Primarily
May and early June.
All year. Not deeper than 21.
on sandy bottoms.
Feed primarily on cruetacea,
particularly Cancer crabs. Also
consume fish fry and are considered
to be significant herring egg
predators.
Omnivorous.
Os.eridae
Osmerua mordax
Labrador to Florida.
Cuif of Maine in summer.
Anadromous.
Eggs adhesive,
demersal; larvae
pelagic.
crabs.
Fresh or barely
brackish coastal
streams. 4—12 C.
Feeds on small crustaceans, primar-
ily decapoda, mysids, and
gamasrlds. Also feed on,small fish
shellfish, squid, annelid worms, ad
(5 Sturgeona
I Short—nosed
_. Sturgeon
Acipeoseridae
Rcipenser
brevirost rum
CuIf uf Maine. A rare and
endangered species.
Anadromous.
Late April (to
lover Hudson).
Spawns i rivers.
Salmomidae
Salmo saLar
Canada to northern Florida. Center
of abundance lies between Cape Cod
and Cape Hatteras.
Anadromous. Eggs May—early June.
and larvae are
pelagic. Eggs
semi—buoyant.
From Greenland to Massachusetts. Anadromous.
Eggs demersal.
From Newfoundland to the mouth of
Chesapeake Bay. Most abundant in
Massachusetts Bay and between
Cape Cod and Long Island.
Eastern shore of Nova Scotia to
South Carolina. Center of distribu-
tion lies between Cape Cod and
Delaware Capes.
Brackish to fresh water
of Hudson River 14—IS C,
as high as 20 C.
Late Oct.— early Nov. Streams, level
gravelly bottom.
Eggs and larvae May-Oct.
are pelagic.
Opportunistic. Mostly consume
shad, river herring, and menhaden.
Also, eat crabs, shrimp, squid,
clams, and other invertebrates.
Eats small fish (herring, capelin,
and whiting) and amphipods and
shrimp.
Throughout their range, Omnivorous.
coastal, 10—Il C.
Lower estuaries and
shallow coastal areas.
Chiefly below Cape Cod.
Scuiples
Longhorn
Sculpin
Western
Atlantic
Common Name Scientific Name Range and Distribution Spawning Type Spawning Time Spawning Areas Feeding
Cottidae
Myoxocophal Us
act odeceizspinosua
Atherimtdae
Menidia menldla
Bajidse
Raja erliiscea
Labrador to Florida.
Summer in Gulf of Maine. Extremely
abundant south of Cape Cod.
lt.
Rainbow
Smelt
Eggs demeraal,
adhesive, larvae
pelagic.
Fertilization is
internal; lays
eggs.
Shallow bays and
marshes, 15-22 C,
over sandy bottoms.
Once a year.
March—Nay.
Percicbthylidae
Morons saxatills
Temperate
Basses
Striped Bass
Trout.
Atlantic
Salmon
Wrasse.
Cunner
Predominantly prey upon benthic
invertebrates; primarily decapoda,
amphipods, iaopoda, polychnetes,
and molluscs. Also eat fish.
Labridae
?autogolabrus
adspersus
Tautog Tautoga onitis
Eggs and larvae
are pelagic.
Early to aid—summer.
May—August.
Feed on invertebrates (chiefly
univalve and bivalve molluscs,
mussels, and barnacleq), Also eat
crabs, sand dollars, scallops,
snphipods, shrimps, ialpod , And
lobsters. May also prey upon sea
worms.
Source: Mapted From Bigelov and Shroeder, 1953; TRICOM, 1984; Crosqleln and Aznrovitz, 1982.
-------
Barndoor Skate
Little Skate
Thorny Skate
Blueback Herring
Alewife
Atlantic Herring
Goosefish
Pourbeard Rockling
Atlantic Cod
Haddock
Silver Hake
White Hake
Conner
Snake Blenny
Daubed Shanny
Radiated Shanny
Atlantic Wolfflsh
Wrymouth
Redfiah or Ocean Perch
Sea Raven
Longhorn Sculpin
Mouatache Sculpin
Alligatorfish
Fourspot Flounder
W Indowpane
Witch Flounder
American Plaice
Atlantic Halibut
Yell taiL Flounder
Winter Flounder
Spiny Dogfish
Ocean Pout
Atlantic Silveraide
Pollock
Red Hake
American Shad
Atlantic Mackerel
Adapted from Lux and Kelly. 1918
RaJa er nacea
Raja radiata
Liosa aestivaIls
Li era pseudoharengus
Clupea hsrengus hirengus
Lophius americanus
Enchel yepus ciabr us
Gadus morhua
Melanogrammus aegl of nus
ter1uccius bflinearis
Urophycis tenuls
Tautogola brus adspersus
Lumpenus I uepretaef orm s
Wmpenus aaculatus
UI varia subb lfurca ea
Anarhachas lupus
Cryptacanthodes aacula tus
Sebastes mar nus
Hemlcrlpterus ameracanus
Nyoxocephal us octodeceaspinosus
Trlglops wrrayi
Aspidophoroides monopterygius
Paralichthys oblongus
Scophthalwus aquesus
Cl yptocephal us cynoglossus
Hippoglossoides platessoldes
Hlppcglossossus hippoglossossus
L aanda Eerruganea
Pseudopl euronectes americanus
Squa lus acanthlas
Nacrozoarces ameracanus
Ken ldla menidia
Pollachius vlreras
Urophycls chuss
Alosa sapidissiea
Scomber sconabrus
<2
6
38
11
3
90
4
<1
2
71
<1
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TABLE C. 1.1. AVERAGE ABUNDANCE PER TOW OF DF 1ERSAL FISH COLLECTED BY THE MASSACHUSETTS
DIVISION OF MARINE FISHERIES IN SPRING (MAY) AND FALL (SEPTFXBER) Bwi1 M TRAWLS IN
MASSACHUSETTS BAY FROM 1978 THROUGH 1986
Average
Spring Stations
Common Name Species 9-18m 18-27m 27-37m
Abundance
Per Tow
Fall Stations
9-18m
18-27m
27-37m
Spiny Dogfish
Little Skate
Winter Skate
Thorny Skate
Blueback Herring
Alewife
American Shad
Atlantic Herring
Rainbow Smelt
Goosefish
, Fourbeard Rockling
‘ ° Atlantic Cod
Haddock
Silver Hake
Pollock
Red Hake
Spotted Hake
White Hake
Ocean Pout
Atlantic Saury
Atlantic Silverside
Black Sea Bass
Tautog
Cunner
Snake Blenny
Daubed Shanny
Atlantic Wolff ish
American Sand Lance
Atlantic Mackerel
Butterfish
Squalus acanthias
Raja erinacea
Raja ocellata
Raja radiata
Alosa aestivalis
Alosa pseudoharengus
Alosa sapidissima
Clupea harengus harengus
Osmerus mordax
Lophius americanus
Enchelyopus cimbrius
Cadus morhua
Melanogrammus aeglefinus
Merluccius bilinearis
Pollachius virens
Urophycis chuss
Urophycis regius
Urophycis tenuis
Macro zoarces americanus
Scomberesox saurus
Menidia menidia
Centropristis striata
Tautoga onitis
Tautogolabrus ads persus
Lumpenus lumpretaeformi S
Lumpenus maculatus
Anarhichas lupus
Ammodytes an?ericanus
Sconiber scombrus
Peprilus triacanthus
3
1
2
<1
<1
I I
115
I I
51
3
3
100
<1
<1 4
<1 —
<1
(1
<1
200
—
65
<1
-
2
11
15
5
(1
—
(1
1
1
-
-
2
I l
<1
7
(1
I I
<1
2
—
—
—
<1
3
1
7
<1
—
.
52
—
—
10
—
51
(1
-
—
1 17
9
—
9
<1
—
13
lj
39
<1
5
<1
31;
9
<1
1
(1
<1
7
93
85
<1
29
—
33
19
—
13
1;
6
9
I l
12
<1
117
1$
17
<1
(1
61
(1
<1
2
(1
99
3
11
3
5
3
108
<1
<1
<1
(1
1 1 11
— (1
(1 2 209
continued
-------
TABLE C. 1.1. (Continued). AVERAGE ABUNDANCE PER T J OF DEMERSAL FISH COLLECTED BY THE MASSACHUSIcnS
DIVISION OF MARINE FISHERIES IN SPRING (MAY) AND FALL (SEPTE 1BER) B YrrOM TRAWLS IN
MASSACHUSETFS BAY FROM 1978 THROUGH 1986
0
Common Name
Species
Average
Abundance
Per Tow
Spring
Stations
Fall
Stations
9-18m
18-27m
27-37m
9-18m
18-27m
27-37m
Northern Searobin
Prionotus carolinus
<1
-
<1
—
—
—
Sea Raven
Hemitripterus americanus
<1
2
1
1
<1
<1
Longhorn Sculpin
Myoxocephalus octodecemspinosus
5
1 6
208
1
12
78
Alligatorfish
Aspidophoroides monopterygius
-
-
<1
-
-
<1
Lumpfish
Cyclopterus lumpus
<1
-
<1
—
—
—
Summer Flounder
Paralichthys dentatus
-
-
<1
-
-
-
Fourspot Flounder
Paralichthys oblongus
<1
<1
1
(1
3
3
Windowpane
Scophthalmus aquosus
23
11
17
11
6
—
Witch Flounder
Glyptocephalus cynoglossus
-
1
1
-
-
<1
American Plaice
Hippoglossoides platessoides
<1
7
1 18
<1
<1
15
Yellowtail Flounder
Limanda ferruginea
19
92
63
18
51j
15
Winter Flounder
Pseudopleuronectes americanus
1110
307
1117
380
271
87
No. of Tows
Average Total Abundance
per Tow
13
<381
12
<763
111
<661
2
<383
9
<707
8
<727
Data Source: Letter to EPA from MDMF, 1987
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suitable inshore areas in spring; however, they generally do not migrate a great
distance (Howe and Coates, 1975). Atlantic cod (Gadus morhua) and ocean pout
(Macrozoarces americanus) are also abundant in May but declined substantially in
September. These two species are relatively less abundant in the shallower waters
in both May and September. Cod are known to migrate south to spawn in warmer waters
during fall and winter. Ocean pout spawn In southern New England waters (including
the present study area) in fall (Grosslein and Azarovitz, 1982). A total of 42
species have been collected in these DMF surveys over the sampling period. Total
abundance of all species combined tends to decrease from May to September at all
depths. -
All of the species collected by MWRA (STFP, V,V, 1987) were also collected in DMF
surveys with two additional species observed by MWRA, the radiated shanny (Ulvaria
subbifurcata) and the clearnose skate (Raja elganteria).
Table C.1.m shows the abundance of shellfish collected in the same DMF trawls from
1978 through 1986. The data indicates that American lobster (Homarus americanus) is
the most abundant epifaunal shellfish species in May for all depths. Its numbers
tend to increase in deeper offshore water in September as does the rock crab (Cancer
irroratus).
C.1.1s.3 Fish Communities in Boston Harbor
Winter flounder are abundant throughout Boston Harbor. This species appears to
dominate in the northern part of the Harbor (west of Deer Island). Dermersal fish
density is high in the northern part of Boston Harbor but species diversity is low
(MDC, 1981k). In the southern part of Boston Harbor (in the vicinity of Nut Island),
density of fish is lower than the northern harbor but diversity is higher. Pollock,
cod, skate, and cunner were also relatively abundant in the southern portion of
Boston Harbor (MDC 198L ; DMF, 1979). HaedrIch and Haedrich (197Z ) found winter
flounder dominating the fish population within the upper reaches of the inner harbor
at the mouth of the Mystic River. In spring and early summer smelt and alewife were
also abundant in this area.
C- 4 1
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TABLE C. 1 .m AVERAGE PER TOW OF SELECTED EPIBENTHIC SHELLFISH COLLECTED BY THE
MASSACHUSETTS DIVISION OF MARINE FISHERIES IN SPRING (MAY) AND FALL (SEPTEMBER) BOT CN TRAWLS IN
MASSACHUSETTS BAY FROM 1978 ThROUGH 1986
Scientific Name
Common Name
Average
Abundance
Per Tow
Spring Station
Fall Station
9-18m
18-27m
27-37m
9-18m
18-21m
27-37m
Homarus americanus
Northern lobster
3
8
2
98
87
22
Cancer irroratus
Rock crab
22
3
<1
112
59
1 W
Cancer boreaulis
Jonah crab
3
2
<1
Il
7
5
Data Source: MDMF
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C.i.’i. i Demersal Fish and Epibenthic Shellfish Contamination
Several studies have been conducted documenting demersal fish and epibenthic tissue
contamination in Boston Harbor and Massachusetts Bay. (Boehm et al., 1984, McDowell
Capuzzo et al., 1986; MDC, 1984, 1979; Schwartz, 1987). Boehzn et al. (1984) made a
comparison of tissue concentrations of pollutants in organisms from Boston Harbor to
those in organisms in Massachusetts Bay, revealing a trend of increased
contamination with increased proximity to Boston Harbor. The following is a
discussion of this study.
Three demersal species, winter flounder (Pseudopleuronectes americanus), American
plaice (Hippoglossoides plattesoides), and a crab (Cancer borealis) were analyzed
for tissue concentration of PCB and PAH (Boehm et al., 1984). Stations where
species were collected were located both in Boston Harbor and Massachusetts Bay (Fig
C.1.m). In general, concentrations in crabs from Boston Harbor were approximately
four times higher than those in Massachusetts Bay. The levels of PCB in the crabs
were greater than levels in winter flounder which were greater than plaice (Table
C.1.n). PCB levels in crabs ranged from 0.065 to 0.279 ppm on a wet weight basis.
The FDA action limit of PCB concentrations on a wet weight basis is 2ppm.
PCB concentration in winter flounder ranged from 0.065 to 0.135 ppm on a wet weight
basis. The PCB concentration found in flounder further offshore (Station MB-i) was
lower than any of the Boston Harbor specimens, (Boehm et al., 1984). The wet weight
PCB concentration in offshore dab were the lowest of all the animals, ranging from
0.01 to 0.03 ppm.
The results of the PAH analysis for crabs are shown in Table C.1.o. PAH levels in
Boston Harbor crabs were much higher than those found outside the harbor. Levels of
individual PAH’s levels in winter flounder in Boston Harbor and Massachusetts Bay
were very low, generally less than 10 ppb. The offshore plaice also contained very
low PAH levels with only trace (0.25 ppb) amounts in any samples (Boehm 19814).
The presence of elevated tissue concentration of PCB’s and PAH’s in the demersal
species in Boston Harbor and vicinity may be the result of the current wastewater
discharges in Boston Harbor. PCB’s and PAH’s from the present discharges may
C_1 13
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116—4
0
Me-I •
•
SITE 4
0
•
LEGEND
STATION LOCATIONS
FROM BOEHM et al., 1984
ALTERNATIVE OUTFALL
LOCATIONS
SOURCE: BOEHM, 1984
FIGURE C.l.j. LOCATIONS OF SAMPLING STATIONS FOR DETERMINATION OF PCB
•
SITE 2
Me- 6
0
I
MS—tO
0
AND PAH CONTAMINATION
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TABLE C. 1 .n SUMMARY OF PCB DATA ON ANIMAL TISSUES IN BOSTON HARBOR AND MASSACHUStcriS BAY
U,
Total
PCB Concentration
Wet
Dry
Lipid
Weight
Weight
Weight
basis
basis
basis
%
Aroclor
%
Aroclor
%
Aroclor
Species
Station
(ug/g)
(ug/g)
(ug/g)
12112
12511
1260
Jonah Crab
(soft parts)
BH—2
BH-5
BH-6
MB-i
0.21 12
0.279
0.235
0.065
0.982
1.250
0.876
0.278
200
238
256
178
16.8
12.3
11.2
11.6
57.7
60.1
511.0
111.7
25.5
27.6
311.8
53.6
Winter Flounder
(edible flesh)
BH-1
BH_2a
BH-5
BFl-6
MB—i
0.135
0.09141±0.009
0.093
0.090
0.065
0.613
0.385±0.035
0.377
0.353
0.116
37
18±1.6
17
15
1 11
15.3
17.9
15.11
15.5
15.0
53.1
53.9
55.0
56.0
511.0
31.6
28.2
29.3
28.5
27.5
Dab
(edible flesh)
MB-3
MB-H
MB—6
MB-b
0.020
0.010
0.0311
0.028
0.098
0.0115
0.131
0.116
5.8
2.1
6.6
5.6
6.1
15.8
9.2
9.5
611.8
117.11
58.8
511.2
29.1
36.8
31.9
36.3
a Triplicate analyses performed
Source: Boehni et al., 19811
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TABLE C.1.o PAH CONCENTRATIONS IN CRABS (ng/g dry weight)
Station
PAH compounds BFI-2 BH-5 BH-6 MB-i
Naphthalene (N) 16 10 12 11
C 1 N 2 1 414 7 3
C 2 N 31 28 9 15
C 3 N nd nd 3 nd
C 14 N nd nd 1 nd
Biphenyl 7 14 3
Fluorene (F) nd 1 1 nd
C 1 F nd 8 nd nd
C 2 F nd 13 nd nd
C 3 F nd nd nd
Phenanthene (P) 5 25 30 3
C 1 P 1 9 17 nd
C 2 P nd 5 9 nd
C 3 P 83 280 nd nd
C 14 P nd nd nd nd
DBT (Dibenzothiophene) nd <1 1 nd
C 1 DBT nd 6 1 nd
C 2 DBT rid 14 nd nd
C 3 DBT nd 3 nd rid
Flouranthrene nd 2 6 nd
Pyrene
Ber izanthraocene nd nd nd 2
Chrysene nd nd nd <1
Benzofluoranthene nd 11 11 nd
Benzo(e)pyrene rid nd nd
Benzo(a)pyrene rid nd nd 22
Total PAH 1 45 1457 111 61
nd — less than 1 ng/g.
Source: Boehm et al., 19814
C_LI 6
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accumulate in the sediments and are then transferred to these demersal organisms as
they feed and as they otherwise contact the sediment.
MWRA is conducting bioaccumulation studies in support of the Secondary Treatment
Facilities Plan; however, this data is not yet available.
C.1.5 MARINE MAMMALS
C.1.5.1 Whales
Finwhales, humpback whales, minke whales, right whales and sei whales have been
known to occur in Massachusetts Bay. All of these species with the exception of the
sei whale are listed on the federally endangered species list. Table C.1.p
summarizes the ranges of these species. These species primarily occur offshore of
the study area (NMFS, 1988; Kenney and Winn, 1987). The highest use areas by whales
in the vicinity of the study area is Stellwagen Bank and the basin area just west of
the bank (Kenney and Winn 1987).
Finwhales (Ralaenoptera physalus) are the most widely distributed whale species in
the shelf waters of the northwest Atlantic (Leatherwood et al., 1976). Limited
migration generally occurs in shelf waters from Cape Cod north to Labrador in June
and July. This species moves south and offshore during winter. The finwhales feed
on schooling fishes (Atlantic herring and American sand lance) as well as
euphausiids and copepods. All coastal Massachusetts and Maine waters are considered
feeding grounds for finwhales (Chu, 1986). CETAP (1982) estimates the abundance of’
finwhales in the Gulf of Maine to range from approximately 3,000 individuals in
spring down to 200 in winter. The greatest densities occur from Jeffrey’s Ledge and
Steliwagen Bank south along the 100 meter contour outside of Cape Cod and the Great
South Channel. These geographic locations are shown on Figure C.1.c.
The humpback whale (Megaptera novaeangliae) is found in the northwest Atlantic
between mid-March and November with major concentrations occurring off the coast of
Newfoundland and Labrador, and in the Gulf of Maine off the New England coast
(Whitehead et al., 1982). During this period their primary activity is feeding.
Humpbacks migrate south to the West Indies in winter where the primary activity is
breeding.
C_147
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TABLE C. 1.p SUMMARY OF WHALE DISTRIBUTION AND ABUNDANCE IN THE WESTERN PORTION OF THE NORTH AThANTIC OCEAN
Estimated
Abundance
Western
Atlantic
in Western
Dominance
in
Species Name Range and Distribution Habitat
North Atlantic
Gulf of Maine
Finback whale
Balaenoptera
physalus
Population centered between
zjl°21’N and 57°O0’N and from
coast to 2000 m contour
Pelagic, but enter bays
and inshore waters in
late summer
7,200
Dominant large
whale; one of most
common cetaceans
Humpback whale
Megaptera
nova eangi i ae
Common near land, but can be
found in deep ocean
Approaches land more
closely and commonly
than other large whales;
also found in deep ocean
800-1 ,500
Routinely seen but
much reduced from
past abundance
Minke whale
k Balaenoptera
acutarostrata
Chesapeake Bay to Baff in Island
in summer, eastern Gulf of
Mexico, northeast Florida and
bahamas in winter
Pelagic, but may stay
nearer to shore than
other rorquals (except
humpback)
No estimates
Less common than
finback, but
sightings are
routine
Right whale
Eubalaena
glacial is
New England to Gulf of St.
Lawrence; possibly found as
far south as Florida
Pelagic and coastal;
not normally inshore
200-1 ,000
Much reduced from
former importance;
rare
Sei whale
Balaenoptera
borealis
New England to Arctic Ocean
Pelagic, does not usually
approach coast
1,570 off
Nova Scotia
Much less common
than finback
Adapted from TRIGOM, 1974 and CeTAP, 1982.
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The primary food source for humpback in the Gulf of Maine is small schooling fish
including Atlantic herring (Clupea harengus harengus), mackerel (Scomber scombrus),
pollock, (Pollachius virens) and American sand lance (Aminodytes americanus) (Kraus
and Prescott, 1981). Sand lance appeared to be the only prey of huznpbacks on
Stellwagen Bank between 1975 and 1979 (Mayo, 1982). Population estimates of
humpbacks in the North Atlantic range from 2000 to 6000 indIviduals. In the Gulf of
Maine estimates range from 200 to 600 individuals (CETAP, 1982).
The northern right whale (Eubalaena glacialis) is one of the most endangered whale
species in the world. Small numbers of right whales occur in the Gulf of Maine and
western Georges Bank between December and March. - In the spring, concentrations of’
right whale in the Gulf of Maine generally occur in the Great South Channel (east of
Cape Cod), Cape Cod Bay north to Jeffrey’s Ledge and northern Gulf of Maine (Kraus
et al., 19814). Only a few sitings of right whale have been made in Massachusetts
Bay through the summer (Kraus et al., 19814). Right whales feed on copepods and
euphausiids. They feed by “skimming” the surface waters with their mouth open.
Estimates of population density of this species in the Gulf of Maine range from 0 in
winter and fall to 1 14 in summer and 166 in spring (CeTAP, 1982). Some right whales
do occur in Cape Cod bay during winter (Mayo, 1986).
The sei whale (Balaenoptera borealis) ranges in the western north Atlantic from
Greenland south to southern New England. In early June sei whales migrate north
from their winter range (between Florida and Cape Cod) and arrive on Georges and
Browns Bank and in the northwest Channel by mid to late June (Mitchell and Kozicki,
19814). The sei whales, like the right whales, feed by “skimming” primarily on
copepods and euphausiids (Mitchell, l97Ltb). The number of’ sei whales in the Gulf of
Maine has been estimated to be 100 (Scott et al., 1981).
The minke whale (Balaenoptera acutarostrata) is a small, widely distributed whale.
In New England waters, it is most frequent in August, but rare in winter (Tomilin,
1957). The northwest Atlantic population of minke whales summers along the coast
between Cape Cod and Ungava Bay, Labrador, and winters offshore and south to Florida
(Sergeant, 1963). Populations of this species number within the tens of thousands
C- 149
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within the northwestern Atlantic Ocean (TRIGOM, 1971 ). Of all the baleen whales,
minke appear to have the greatest dependence on fish as a food source (Tomilin,
1957). In northern waters, herring (Clupea sp.) and capelin (Mallotus villosus) are
common food. Krill appears to be a less common food source for minke than for other
whales.
C.1.5.2 Seals
Two species of pinnipeds, harbor seals (Phoca vitulina) and the gray seal
(Halichoerus grypus) are known to occur in Massachusetts Bay and the Gulf of
Maine. The harbor seal is found year-round in inshore waters basking on nearshore
half-tide ledges and islands. The gray seal is found among the harbor seals only
during the warmer summer months. Gray seals are capable of long periods of pelagic
existence. Table C.1.q summarizes the distribution and abundance of these two seals
(TRIGOM, 19711).
C. 1.6 MARINE TURTLES
Three species of marine turtles are known to occur in Massachusetts Bay, the
leatherback turtle (Demochelys coriacea) Kemp’s Ridley’s turtle (Lepidochelys Kempi)
and the loggerhead turtle (Caretta caretta). Loggerheads are listed as
threatened. Leatherbacks and loggerheads are listed as endangered and threatened
respectively by NMFS. Leatherback turtles are highly pelagic. Sitings off
Massachusetts are most common from July to September (CeTAP, 1982). Ridley’s
turtles occur off southern New England in summer. This species uses inshore
embankinents, estuaries and harbors to feed (NMFS, 1988). Loggerhead turtles are
rare north of Cape Cod. Generally, Massachusetts is the northern range limit for
loggerheads, therefore these waters are marginal habitat (Payne and Ross, 1986).
C.1.7 SEABIRDS
Manomet Bird Observatory (MBO) has conducted standardized bird surveys east of the
present study area in Steliwagen Basin from 1980 to 1985. The species observed in
these surveys are typical of the Gulf of Maine and are generally the same species
that would occur in the present study area. Dominant taxa include a]cids, gulls and
C-50
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TABLE C.1.q PINNIPED SPECIES IN THE GULF OF MAINE
Relative
Western Atlantic
Dominance in
Range or
Abundance
in
Massachusetts
Family Common Name(s) Species Name Distribution Habitat Gulf of’ Maine
Waters
Phocidae Harbor seal Phoca vitulina Labrador to Rhode Inshore residents 6000 ± Maine Common
or common concolor Island; occasion- of bays and es- waters 5000-
seal ally to Carolinas tuaries. Breeding 6000 Canadian
sunning, and Maritime
resting on half— provinces
tide ledges.
Breed north of
Massachusett Bay,
late April. Feed
opportunistically
on small schooling
fishes.
Phocidae Gray seal or Halichoerus Gulf’ of St. Law- Remote coastal 18,000 Man- Uncommon in
Atlantic seal grypus rence to coast of’ ledges and sand time province U.S. Gulf of
“horsehead Newfoundland; S. shoals. Breeding waters 100± Maine waters
seal” to Massachusetts occurs mid winter; seasonally
feed on fish in Maine;
including breeding
alewives, sand colony of
lance and herring 100 at
Nantucket
Source: TRIGOM, 1971k; Payne and Schneider, 198! ; Shusman, 1983
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shearwaters. Of the species occuring in the study area, Leach’s storm-petrel is
listed as threatened by the state of Massachusetts. Table C.1.r summarizes the
feeding behavior of the dominant species. Some coastal species including seaducks,
grebes, loons, petrals and terns may also occur in the study area.
C-52
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TAILg C. I • r. SUIOIART 0? DOIIINAJIT SEABIRD QIARACTIRISTICS
Common Name Species Abundance in Gulf of Name Feeding
Alcid
Atlantic Puffin
Black Guillemot
Common Hurre
Dovekie
Raxorbi ii
Thick—billed Hurre
Gull
Fratercula art ica
Cepphus gryllo
UrAa aalge
AXle ella
Alca torda
Uria lomvia
All species are present from
November through Nay except for the
Black Cut Ilemoc which ia found only in
the winter.
Pursuit—divers which teed as secondary and tertiary carnivores
on macroplankton, cephalopods, and fish.
Puffins feed almost exclusively on fish. including species of
the following genera: Ammodyte.. Clupea. Gadua, and Hallotus.
Black—legged Kittiwake
Bonaparte’a Cull
Glaucous Cull
Great Black—backed Cull
Great Black—backed Cull
herring Cull
Iceland Cull
Ring—billed Cull
Jaeger
Rissa trldactyla
Larus Philadolplua
L. llyperboreus
L. marinus
L. argentatus
I.. glaucoides
7.. delawarensis
The Great Black—backed Gull is the
dominant gull species found and can be
seen throughout the year; Herring.
Glauco.. and Iceland Gulls are present
fall through spring; the Ring—billed
Gull is present during summer and fall;
Bonaparte’s Gull is found in fall and
winter; and Black—legged Kittiwakes are
common from September to Hay.
Feed as secondary and tertiary carnivores on crustaceans, fish,
and as scavengers of offal.
The large gulls also, feed as upper level carnivores on birds, eggs, and
carrion.
Parasitic Jaeger
Pomarine Jaeger
Stercorarius parasiticus
S. pomarii’Us
Parasitic Jasgers are present it relatively
Uncommon, and Pomarine Jaegera are found in
both sumi.et
Feed as secondary and tertiary carnivores on crustaceans, fish.
offal. At sea they also feed at the surface or by pirating other birds.
Northern Fulmar
Northern Gannet
Phalarope
Fulmorus giacialia
Sole bassanus
Present throughout the year with greatest
densities occurring in the winter.
Abundant fall through spring.
Opportunistic, at surface teed as secondary and tertiary carnivores and as
scavengers on zooplankion, fish, squid, and offal.
Feed as tertiary carnivores principally on schooling fish and to a lesser
extent on squid. They will also scavenge offal fro. fishing vessels and
take fish from near surface fishing nets.
Red—necked (Northern)
Phalarope
Red Phalarope
Shearwater
Phalaropus lobatus
Phalaropis fulicaria
Red Phalarope found in spring and fall and
Red-necked (Northern) Palarope is present
in summer.
Feed at the surface a. secondary carnivores on planktontc crustaceans
and the eggs and larvae of fish and squid.
Cory’s shearwater
Greater shearwater
Itnnx ahearwater
Sooty shearwater
Storm—Petrel
Calonectris diomedea
Puffinus gravis
P. Puff Anus
P. grisous
Greater Shearwaters are dominant from Nay to
early December; Sooty Shearwaters found from
April to November (greatest densities
occuring In summer); and Hana and Cory’s
Shearwatera are present throughout the summer
and fall.
Feed at or in near—surface waters as secondary and tertiary carnivores on
fish, squid, and cruatanceans. Greater Shearwatera and
will also scavenge offal fro. fishing vessels.
Leach’s Storm—petrel
Wilson’s Storm—petrel
Oceanodroma lcugorhoa
Oceanztes oceanicus
Both species are found from April to November
with the greatest densities occurring in
summer.
Feed primarily at the surface as secondary carnivore, on xooplankton, and
to a lesser extent as tertiary carnivore on small fish end cehalopods.
Wilson’s Storm-petrel will also scavenge offal from fishing and whaling
vessels.
Source: Hanomet Bird Observatory. 1985 (unpublished dnta)
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C-55
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REFERENCES (Continued)
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ROV Reconnaissance I.
MWRA, STFP V, 0, 1987. Secondary Treatment Facilities
ROV Reconnaissance II.
MWRA, STFP V, P, 1987. Secondary Treatment Facilities
REMOTS Reconnaissance I.
MWRA, STFP V, Q, 1987. Secondary Treatment Facilities
REMOTS Reconnaissance II.
MWRA, STFP V, R, 1987. Secondary Treatment Facilities
Sediment Grain Size Sampling.
MWRA, STFP V, S, 1987. Secondary Treatment Facilities
Benthic Chemistry Sampling.
MWRA, STFP V, T, 1987. Secondary Treatment Facilities
Benthic Biology Sampling.
MWRA, STFP V, U, 1987. Secondary Treatment Facilities
Fish & Epibenthic Shellfish.
MWRA, STFP V, V, 1987. Secondary Treatment Facilities
Fish Histopathology.
MWRA, STFP V, Y, 1987. Secondary Treatment Facilities
Nutrient Analysis.
MWRA, STFP V, Z, 1987. Secondary Treatment Facilities
Primary Productivity Program.
Plan,
Plan,
Plan,
Plan,
Plan,
Plan,
Plan,
Plan,
Plan,
Plan,
Plan,
Volume
Volume
Volume
Volume
Volume
Volume
Volume
Volume
Volume
Volume
Volume
V, Appendix N,
V, Appendix 0,
V, Appendix P,
V, Appendix Q,
V, Appendix R,
V, Appendix S,
V, Appendix T,
V, Appendix U,
V, Appendix V,
V, Appendix Y,
V, Appendix Z,
Mayo, C.A., 1982. Observations of Cetaceans: Cape Cod Bay and Southern Stellwagen
Bank Massachusetts 1975-1979. NTIS Report No. PB82-186263.
McDowell Capuzzo, J., A. McElroy, and G. Wallace, 1986. Fish and Shellfish
Contamination in New England Waters: An Evaluation of Available Data on the
Distribution of Chemical Contaminants.
Metropolitan District Commission (MDC). 1 9 8L1. Application for a Waiver of
Secondary Treatment for the Nut Island and Deer Island Treatment Plants, Vol. II
and Supplement.
Mitchel, E., 197L1. Trophic Relationships and Competition for Food in the Northwest
Atlantic, Proc. Canad. Soc. Zool. Ann. Meeting , pp. 123—132.
C-56
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REFERENCES (Continued)
Mitchel, E. and V.M. Kozicki, 19814. Reproductive Condition of Male Sperm Whales,
Physeter macrocephalus , Taken off Nova Scotia, Reports of the International
Whaling Commission , Special Issue 6:2143-252.
}JMFS. 1988. Letter from Tom Bigford, NMSF, Habitat Conservation Branch to
Gwen Ruta, U.S. EPA. February 16, 1988.
Parker, I.J., 19714. Phytoplankton Primary Productivity in Massachusetts Bay, Ph.D,
Thesis University of New Hampshire.
Payne, P.M. and J.P. Ross, 1986. Loggerhead Turtle (Caretta caretta). In:
T. French (ed.) Endangered, Threatened and Special Concern Vertebrate Species in
Massachusetts. Mass. Div. of Fisheries and Wildlife, Nongame and Endangered
Species Program, Boston, MA 02202 (in press).
Pearce, J.B., 1972. The Effect of Solid Waste Disposal on Benthic Communities in
New York Bight. In: Ruivo, M. (ed.) Marine Pollution and Sea Life. FAO
Fisheries News LTD, Surrey England. p. 14014_tIll.
Pearson, T.H. and R. Rosenberg, 1978. Macrobenthic Succession in Relation to
Organic Enrichment and Pollution of the Marine Environment, Oceanog. Mar. Biol.
Ann. Rev . 16:229-311.
Quinlan, A.V., T. Lewis and J.K. Hoyt, 1983. Fouling of the Sandy Beaches of Nahant
Bay (Massachusetts, USA) by an Abnormal Free-Living Form of the Macroalga
Pilayella littoralis (Phaeophyta). I Habitat Characteristics, 114 pp. In: A.N.
McLachlan and T. Erasmus (eds.), Sandy Beaches as Ecosystems, W. Junk Publishers,
The Hague, The Netherlands.
Rowe, G.T., P.T. Polloni and J.I. Rave, 1972. Benthic Community Parameters in Lower
Mystic River. mt. Revise Geo. Hydroloiol . 57( 1O:573_5814.
Schwartz, J.P., 1987. PCB Concentrations in Marine Fish and Shellfish from Boston
and Salem Harbors, and Coastal Massachusetts, Progress Report No. 114,
997-36-110-8-87-CR, MDMF.
Scott, G.P., R.D. Kenney, J.G. Gilbert, and R.K. Edel, 1981. Estimates of Cetacean
and Turtle Abundance in the CETAP Study Area with an Analysis of Factors
Affecting Them. In: A Characterization of Marine Mammals and Turtles in the Mid-
and North Atlantic Areas of the U.S. Outer Continental Shelf, Annual Report,
1979, CeTAP Program. Prepared for USDI/BLM.
Sergeant, D.E., 1963. Minke Whales, Balaenoptera acutorostrata Lacepede, of the
Western North Atlantic, J. Fish . Res. Bd. Can. 20:11489-15014.
SPSS/PC+, SPSS, Inc., M.J. Norusis, 1986.
Steimle, F., J. Caracciolo and J. Pearde, 1982. Impacts of Dumping on New York
Bight: Science and Management. Estuarine Research Federation, Columbia, S.C.
p. 213-221.
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REFERENCES (Continued)
Tomilin, A.G., 1957. Manunals of the U.S.S.R. and Adjacent Countries, Vol. 9,
Cetacea. Trangi. No. 11214, Israel Prog. Sc Translation , Jerusalem (1967).
TRIGOM (The Research Institute of the Gulf of’ Maine), 19714. A Socio-Economic and
Environmental Inventory of the North Atlantic Region, Including the Outer
Continental Shelf and Adjacent Waters from Sandy Hook, New Jersey, to Bay of
Fundy, Vol. 1, Books 3 and 5.
Whitehead H., R. Silver, and P. Harcourt, 1982. The Migration of Hwnpback Whales
Along the Northeast Coast of Newfoundland, Can. J. Zool . 60:2173-2179.
Wilce, R.T. and A.V. Quinlan, 19814. Fouling of the Sandy Beaches of Nahant Bay
(Masshachusetts, USA) by an Abnormal Free-Living From of the Macroalga Pilayella
littoralis (L.) Kjellm (Phaeophyta). II Population Characteristics, in: A.N.
McLachlan and T. Erasmus (eds.), Sandy Beaches as Ecosystems, W. Junk Publishers,
The HAgue, The Netherlands.
Young, D.K., and D.C. Rhoads, 1971. Animal - Sediment Relations in Cape Cod Bay,
Massachusetts, I. — Transect Study. Marine Biology 11:2 42-2514.
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APPENDIX D
HARBOR RESOURCES
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APPENDIX D
HARBOR RESOURCES
D. 1 INTRODUCTION
This appendix describes effects on the resources of Boston Harbor resulting from
construction and operation of the Deer Island secondary treatment facility effluent
outfall and inter-island conduit. Appendix D is organized into three sections:
• Description of the Project;
• Affected Harbor Resources Environment; and
• Environmental Consequences of the Project.
The following harbor resources are described and analyzed in this appendix:
navigation, commercial shipping, commercial fishing, recreation areas and
facilities, and cultural and archaeological resources. Construction of facilities
is described in detail to provide understanding of construction activities which
have a high potential for impacting harbor resources.
D.2 DESCRIPTION OF THE PROJECT
D.2.1 CONSTRUCTION OF FACILITIES
The major component of the cleanup of Boston Harbor is a secondary wastewater
treatment facility which will be built on Deer Island during the period 1990-2000.
An effluent outfall will be constructed to convey treated wastewater from the
treatment plant to a point in the ocean where it will be discharged through a
diffuser. The existing sewer system conveys wastewater from the southern portion of
the HWRA service area to a treatment facility on Nut Island. The existing Nut
Island treatment plant will be dismantled and replaced by headworks, and sewage from
the southern service area will flow from Nut Island to Deer Island via an inter-
island conduit. Both the effluent outfall and inter-island conduit will be deep
rock tunnels constructed from shafts on Deer Island with all tunnel and conduit
D-1
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construction waste removed at Deer Island. Alternative outfall and inter-island
conduit routes, construction methods, and options for diffuser design are discussed
in detail in Appendix F and Chapter 3 of this Draft SEIS.
In addition to construction—related impacts, the operation of the effluent discharge
can potentially affect harbor resources. However, selection of a discharge location
seeks to avoid or greatly minimize impacts on these resources. Therefore,
construction related impacts on harbor resources are stressed in this appendix.
The U.S. District Court has established a mandatory schedule for treatment
facilities construction. Under this schedule, marine traffic flows generated by
treatment plant, inter-island conduit, and outfall construction will occur within
the harbor at the same time. These marine traffic flows are the element of
construction (including treatment plant headworks, water transportation facilities,
outfall, and conduit construction) and operation with the greatest likelihood of
affecting harbor resources. This appendix addresses marine traffic related to all
construction and focuses upon the period 1990-95 when inter-island conduit and
outfall construction will occur. This appendix also considers effects on harbor
resources from operation of the inter-island conduit and the effluent outfall.
Operations effects are mostly related to transportation of operations workers and
materials and impacts of effluent discharge on harbor resources.
The target dates established by the U.S. District Court schedule for construction of
the treatment facilities, effluent outfall and inter-island conduit are as follows
(MWRA, WTFP 7, 1987):
• Initiate construction of new primary treatment facilities 12/90
• Complete construction and commence operation of new 7/95
primary treatment facilities
• Initiate construction of outfall 7/91
• Complete construction of outfall 7/9 1 !
• Initiate construction of inter-island wastewater L !/91
conveyance system
D-2
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• Complete construction of inter-island wastewater 4/9 14
conveyance system
• Initiate construction of secondary treatment facilities during 1995
• Complete construction of secondary treatment facilities during 1999
D.211 Effluent Outfall
The effluent outfall system (described in Appendix F) includes a vertical access
shaft located on Deer Island, a deep rock tunnel, and a diffuser consisting of
either multiple individual vertical risers drilled into the effluent tunnel from
above and equally spaced over a distance of 6,600 feet or a multiport pipe diffuser
in an excavated trench. Other construction methods, including pipeline and sunken
tube alternatives, have been removed from consideration through screening
(Appendix F). As noted previously, July 19911 is the court-ordered completion date
for the outfall system. However, this date was based on the new outfall diffuser
being located about 3.5 miles from Deer Island. Alternative sites located farther
from Deer Island and in deeper water would delay the estimated outfall system
completion from December 199i4 to May 1995, depending on the site (MWRA, WTFP 5,
1987). Three sites are being considered by this Draft SEIS: Sites 2, 4, and 5
(Figure D.2.a). At the chosen site, treated effluent will be released into the
marine environment from a concrete-lined outfall tunnel as much as 10.2 miles long
and up to 25 feet in finished diameter, based approximately 355 to 1490 feet in deep
rock below sea level (Appendix F). All excavated material from the effluent tunnel
will be removed at Deer Island.
D.2.1.2 Inter-Island Conduit
The inter-island conduit will likely be a deep rock tunnel (Appendix F), connecting
Nut Island to Deer Island so that South System influent wastewater flows can be
treated with North System flows at the new Deer Island Wastewater Treatment Plant.
The deep rock tunnel, 200-300 feet below sea level, will be concrete lined with an
11—foot finished inside diameter, and will fdllow a straight line between vertical
access shafts at Nut Island’s new headworks and the new South System pumping station
on Deer Island, a distance of approximately 211,800 feet (Appendix F). All excavated
D-3
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CARGO
Bulk Sand, Gravel, Cement
Construction and Operations
Equipment and Supplies,
Excavated Materials
Personnel
RO/RO 42 Truck Barge
RO/RO 12 Truck Ferry
RO/RO 6 Truck Supply Boat
150 Person Ferry
55 Person Ferry
1YPICAL VESSELS ROUTE SYMBOLS OTHER SYMBOLS
600 Or 3000 Ton Barges • Piers
0 Barge Mooring Area
— Inter—Island Conveyance
Effluent Outfall
Sources: MWRA STFP Vol. VGG, Vol. VII, Vol. 1 1 1K, 1987.
MWRA Revere, 1987.
MWRA WTFP Vol. 1, Vol. 9, 1987.
FIGURE D.2.a. WATER TRANSPORTS FOR WASTEWATER TREATMENT RELATED
FACILITIES CONSTRUCTION/OPERATION, 1990-1995
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material from the inter-island conduit will be removed at Deer Island. Excavated
material from the Nut Island shaft will be removed at Nut Island.
D.2.2 DESCRIPTION OF THE WATER TRANSPORTATION PROGRAM
The Water Transportation Facilities Program (Figure D.2.a; Table D.2.a) is an
essential supporting element of the entire construction phase of the Secondary
Treatment Facilities Plan, spanning a 10-year period from 1989 to 1999. The program
provides transportation of workers and construction materials required for treatment
plant—related construction. In addition to the work described in Section D.2.1,
other related projects include Treatment Plant Upgrade at Deer and Nut Islands;
Residuals Management, both interim and long-term; Combined Sewer Overflows; and
Harbor Research and Monitoring (MWRA, WTFP 1, 1987).
The Water Transportation Program includes the construction of the piers and related
facilities to move materials, workers and equipment to and from Deer and Nut Islands
via water, thereby reducing road traffic. The environmental impacts of pier
construction are not considered by this Draft SEIS, but are evaluated by the MWRA
Water Transportation Facilities Plan (MWRA WTFP 1-10, 1987), and EPA is preparing an
environmental assessment regarding water transportation facilities. Inter-island
conduit and effluent outfall construction will Involve a 6-day-per-week, 2 1 4-hour-
per—day construction schedule (MWRA, WTFP 7, 1987). Deer and Nut Island piers are
expected to be completed in September 1989 (MWRA, WTFP 5, 1987) and will handle both
materials and personnel. On-shore piers will be completed in May 1990 (MWRA, WTFP
5, 1987) and will consist of two materials handling piers and staging areas located
at the rehabilitated Revere Sugar Site in Charlestowri on the Mystic River (MWRA WTFF
Revere, 1987) and at a rehabilitated portion of the Quincy General Dynamics Shipyard
(MWRA, WTFP 5, 1987) located on the Weyinouth Fore River. Four on-shore worker
transport pier facilities will be located In Quincy at Marina Bay, Hingharn at
Hewitt’s Cove, Boston near North Station (Beverly Street), and Boston at Rowes
Wharf.
In addition to the on-shore and on-island piers, project—related marine traffic will
be generated from other locations including a temporary barge mooring area (MWRA,
WTFP 7, 1987) measuring 300 ft. x 500 ft. approximately 5,000 ft. west of the Deer
D-5
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TABLE D.2.a WATER TRANSPORTATION PROGRAM
Cargo
Origin
Destination
Vessel Type
Bulk Sand Gravel and Cement
Out of Harbor
or Quincy Shipyard
or Revere Sugar
Deer
Nut
Island
Island
600 ton Barge
or
3000 ton Barge
Construction and Operations
Quincy Shipyard or
Deer
Island
RO/RO 112 Truck Barge
Equipment and Supplies;
Revere Sugar
Nut
Island
or
Excavated Materials
RO/RO 12 Truck Ferry
or
RO/RO 6 Truck Supply
Boat
Construction and Operations
Personnel Piers
Deer
Island
150 Person Ferry
Personnel
in Boston (2)
Quincy and Hingham
Nut
Island
or
55 Person Ferry
Sources: MWRA STFP Vol. VGG, IV, VII,
III K, 1987; MWRA STFP Revere, 1987; MWRA
WTFP 1, 5, 1987.
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Island proposed supply arid personnel piers (Figure D.2.a). Also, at the terminus of
the outfall one or two vessels will be drilling risers or dredging the diffuser
trench for about a 2 year period, with worker and supply boats generating
additional marine traffic (MWRA, WTFP 5, 1987). Bulk construction materials may
also be shipped via barge from sources outside the harbor directly to Deer Island
(MWRA, WTFP 5, 1987).
There are five categories of cargo to be shipped to and from Deer and Nut Islands
during the construction period (MWRA, WTFP 5, 1987; MWRA STFP IV, V, 1987):
• Bulk Cargo (sand, gravel, cement) may be shipped via barge from locations
outside the harbor.
• Construction and operations cargo including: construction materials
(reinforcing steel, pipes, pumps, etc.), construction equipment (loaders,
bulldozers, graders, trucks, tunnel boring machine, etc.) and operational
supplies, fuel, etc.) shipped via roll on/roll of (RO/RO) barge, RO/RO
ferries, or supply boats from Revere Sugar (Charlestown) and Quincy.
• Personnel for construction and interim plant operation transported via
personnel ferries from the four on-shore personnel piers.
• Excavated materials from the outfall tunnel and inter-island conduit will
be used as construction fill on Deer Island. Additional excavated
materials from the outfall tunnel, amounting to approximately 0.8 to 1.9
million cubic yards will not be used on Deer Island and will be shipped
via barge, supply boats, or RO/RO ferries through Quincy for upland
disposal or possible use in Third Harbor Tunnel/Central Artery Depression
highway projects.
• Personnel and materials for diffuser construction.
D.2.2.1 Bulk Cargo
Bulk cargo barges carrying sand, gravel, and cement may travel directly to Deer and
Nut Islands from suppliers outside the Boston Harbor area, (MWRA, WTFP 5, 1987) and
may not use the proposed on-shore facilities. Both conduit and outfall tunnels will
have peak concrete production needs in 1992, 1993, and 199i4 (MWRA, WTFP 7, 1987).
To ensure that possible delays in the barging of sand, gravel, and stone do not
cause a shortfall in materials for concrete production during these peak concrete
production years, it may be necessary to ship material in advance of construction
D-7
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and stockpile it on Deer Island. This may require mooring of barges waiting to
unload. Throughout the peak period, the backlog of barges in excess of those that
can be handled at the Deer Island pier may be anchored at the special mooring area
directly north of Anchorage 92 (Figure D.2.a) (MWRA, WTFP 1, 1987).
During the peak concrete demand period, 1992_91 , maintenance of concrete production
to service conduit, outfall, and treatment facility construction may require a batch
plant at Deer Island with a capacity of as much as 1,050 cubic yards per day. The
peak number of 600-ton barges carrying cement, sand, and stone necessary to supply a
batch plant of this capacity is 3.3 per day (MWRA, WTFP 1, 1987); if 3,000 ton
barges are used, approximately one barge every other day is required. A deep draft
tugboat will deliver the bulk cargo barges to a point near the limits of the Harbor
where an Inner Harbor tug would receive the barge and deliver it to the Deer Island
bulkhead or to the temporary mooring area next to Anchorage 92, where anchoring of 3
to Al bulk cargo barges of various sizes is anticipated (MWRA, WTFP 7, 1987).
D.2.2.2 Construction arid Operation Cargo
Construction and operation materials, equipment, and supplies will be the principal
cargo transported to the islands from the on-shore staging areas at the Revere Sugar
Site in Charlestown and the former General Dynamics Shipyard in Quincy
(Figure D.2.a). Two-thirds of the total construction and operation materials bound
for Deer and Nut Islands will pass through the Quincy site and the other third will
be transported from the Revere Sugar site (MWRA, WTFP Revere, 1987). Roll—on/Roll-
off (RO/RO) loading and unloading will be the predominant activity at shore and
island piers, utilizing yet undetermined types of vessels: 2 large barges rafted
together for total dimensions of 80’ x 330’ (tug-assisted) carrying 112 truck
trailers; or large drive-through ferries, 55’ x 210’ with a draft of about 6’
carrying 12 truck trailers; or supply boats (commonly used for offshore oil drilling
supply operations) ranging in size from 35’ x 178’ to ZIG’ x 210’, with a draft of
about 9’, having a capacity of 6 truck trailers (MWRA, WTFP 8, 1987).
D—8
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D.2.2.3 Personnel Transport
Workers for construction and operation will be transported using personnel ferries
up to 150 feet in length with a draft of less than 8 feet, capable of carrying
150-250 people (MWRA, WTFP 8, 1987).
D.2.2.1$ Excavated Material
Excavated material will be shipped from Deer Island in the same way as construction
and operations materials will be shipped to Deer Island (Section D.2.2.2).
D.2.2.5 Diffuser Construction Personnel and Materials
Construction of the diffuser will take place in the open ocean environment.
Depending on the final selected site, the diffuser will be located up to 10 miles
off the Deer Island shoreline in water depths up to 120 ft. Two types of diffusers
survived the screening process of’ this Draft SEIS: drilled vertical riser and
dredged trench (Appendix F). If a drilled vertical riser diffuser is used, risers
would be drilled through the ocean floor into the effluent tunnel. The drilling
rigs at the diffuser site will require periodic deliveries of supplies and personnel
via drilling rig supply boats. Two different types of offshore rigs are available
to the contractor to construct the diffuser: a jack—up barge or a semi-submersible
drilling platform (MWRA, STF?, V, 1987).
The jack-up barge must be towed into position over a riser location. The legs are
then dropped to the ocean floor, fixing the barge’s location. The working platform
is then jacked to a safe height above the ocean surface to protect it from waves.
Construction of the riser is done from the working platform. This procedure must be
repeated each time the barge is moved. The estimated average time to install a
riser and then move the jack-up barge to the next location is two weeks during
favorable weather conditions. To account for all unfavorable weather conditions, a
four-month winter delay has been factored into the schedule. To install 80 risers
within a reasonable schedule, two jack-up barges may be used. With proper
scheduling, the entire diffuser could be constructed within three good weather
D-9
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seasons, or in approximately 30 calendar months. An additional six months is
required for mobilization (MWRA, STFP V, 1987).
An alternative to jack-up barges is a semi—submersible drilling platform. Semi-
submersible rigs are self-propelled floating platforms held in position by anchor
settings. These rigs do not rest on the ocean bottom; however, their working
platforms are located a safe height above the ocean surface. Several types of these
rigs exist, including the AKER H-3 (Modified), built by Aker Engineering A/S of
Oslo, Norway. The rig could work throughout the year off the Massachusetts coast,
and could install one diffuser every 1 to 1.5 weeks. - It is estimated that the
entire 80-riser diffuser could be installed in 20 to 30 calendar months. An
additional six months is required for mobilization (MWRA, STFP V, 1987).
If a dredged trench diffuser is used, barges, dredging vessels, and personnel boats
would travel to the diffuser site from undetermined locations. Dredged material,
amounting to approximately 1. 4 million cubic yards for a 6,600 foot long diffuser,
would be shipped by barge to the Foul Area Disposal Site for ocean disposal
(see section D.3.1.1). Construction time is dependent upon sea floor conditions
which will be determined by planned MWRA geotechnical investigations.
D.2.3 PROJECT-RELATED MARINE TRAFFIC
To evaluate project-related marine traffic (Section D. 1 I.2), peak marine traffic
levels resulting from construction and operation are considered for each category of
cargo (Table D.2.b). Peak bulk cargo traffic would be 3.3 barges with 600-ton
capacity per day or 1 barge with 3,000 ton capacity every other day (MWRA, WTFP 8,
1987). Bulk cargo would travel from outside the harbor via President Roads to Deer
Island or the anchorage.
Peak marine transport of construction materials (1991_199LD would carry 137
truckloads of materials per 8-hour day. Depending on the vessels chosen to carry
the truckloads, this equals 8 one-way barge trips, 2Z one-way large ferry trips, or
1i8 one—way supply boat trips per day (MWRA, WTFP 8, 1987). Approximately 1/3 of
this traffic is anticipated to take place between Charlestown and Deer Island and
2/3 between Quincy and Deer Island (MWRA, WTFP Revere, 1987).
D- 10
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TABLE D.2.b WATER TRANSPORTATION PROGRAJI - TRIPS PER DAY
-S
-S
Cargo
Origin
Destination
Peak Trips
Vessel Type Per Day
Bulk Sand Gravel and Cement
Out of Harbor
or Quincy Shipyard
or Revere Sugar
Deer
Nut
Island
Island
600 ton Barge 3.3
or
3000 ton Barge <1
Construction and Operations
Quincy Shipyard or
Deer
Island
RO/RO 112 Truck Barge
8
Equipment and Supplies;
Revere Sugar
Nut
Island
or
Excavated Materials
RO/RO 12 Truck Ferry
or
RO/RO 6 Truck Supply
Boat
2 I
118
Construction and Operations
Personnel Piers
Deer
Island
150 Person Ferry
211
Personnel
in Boston (2)
Nut
Island
or (Not at
Quincy and Hingham
Vessel
Capacity
55 Person Ferry 211
Source: MWRA STEP V, GG, IV, VII, III, K, 1987; MWRA STEP Revere, 1987; MWRA, WTFP 1, 5, 1987.
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Personnel ferry peak traffic will consist of one round trip per shift between Deer
Island and the four personnel piers, equalling 2Z1 trips per day, eight at each shift
change (MWRA, WTFP 1, 1987).
During construction, traffic to the diffuser site will consist of equipment and
personnel boats and barges, with total numbers of trips dependent upon construction
method. Once construction is complete, operations traffic will consist of personnel
ferries for treatment plant workers and 8-9 barges per month for chemicals and
supplies needed for plant operation.
D.3 AFFECTED HARBOR RESOURCES ENVIRONMENT
This section describes the natural, commercial and recreational resources
potentially affected by the construction and operation of the inter-island conduit
and the effluent outfall. Resources considered are:
Navigation Channels and Anchorages provide commercial and recreational
navigation routes from Massachusetts Bay to Inner Boston Harbor. These
channels and anchorages support shipping, fishing, and recreational water-
dependent uses, and will also be used by construction, material, and
personnel vessels for this project. Impacts on navigation channels and
anchorages are considered for all of Boston Harbor and adjacent
Massachusetts Bay.
• Commercial Shipping contributes significantly to local and regional
economies. The Inner Boston Harbor waterfront supports roughly two dozen
public and private port facilities. Impacts on commercial shipping
traffic and use of port facilities within Boston Harbor are considered.
• Commercial Fishing takes place in Boston Harbor and Massachusetts Bay and
support facilities are located in Boston Harbor. Impacts relating to
disruption of fishing activities from increased vessel traffic and from
outfall diffuser construction are considered for all of Massachusetts Bay
and Boston Harbor.
• Recreation Areas and Facilities are located along the shoreline throughout
the area affected by the project. Potential impacts on recreation include
disruption of recreational activities by marine construction and operation
traffic and effects of effluent on shoreline beaches and parks from Hull
to Nahant, boating and diving areas, and Harbor Islands.
• Sensitive and Protected Areas are natural resources which merit special
consideration due to their fragility and the potential for significant
irreparable damage or immediate risk to public health. Sensitive
resources in Boston Harbor and Massachusetts Bay from Hull to Nahant
D- 12
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include: bathing beaches, clam flats, marine research labs, estuarine
wetlands, Harbor Islands and areas of significant submerged aquatic
vegetation.
Cultural and Archaeological Resources are likely to be directly impacted
only at the outfall discharge site, since all other activities will not
affect the historic and archaeological resources on the sea floor or
shoreline. Only impacts on identified sites near the outfall discharge
alternatives are considered.
A description of harbor resources potentially affected by effluent outfall and
inter-island conduit construction and operation follows. Specific anticipated
impacts of the outfall and conduit alternatives on harbor resources are then
described separately in Section D. 1 4. The impacts described are those which will be
potentially produced by the scenario describing the project found at the beginning
of this appendix.
D.3.1 OVERVIEW OF EXISTING HARBOR RESOURCES
Boston Harbor and Massachusetts Bay provide a varied mixture of recreational,
commercial, and natural resources. These resources, though many are degraded by the
çxisting serious pollution problem, óontinue to support water-dependent industries,
commercial fishing, and recreation in the forms of boating, swimming, and shoreline
activities.
D.3. 1.1 Navigation
Navigational resources make Boston Harbor an important regional economic resource.
The Port of Boston generated 6,917 jobs and contributed 363 million dollars to
regional industries in 1986 (Massport 1987A). The naturally occurring harbor
protection and man—made facilities provide support for an active commercial port.
The major navigation services provided are the maintenance of federally authorized
navigation channels and anchorages provided by the U.S. Army Corps of Engineers and
the private and public port facilities available. Existing navigation channels and
anchorages are shown on Figure D.3.a.
There are two major navigation channels serving Boston Harbor, passing through
President Roads and Nantasket Roads. The channel through President Roads lies
between Deer Island and Long Island. Access to President Roads from Massachusetts
D- 13
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Sources: NOAA Nautical Charts, USACOE, 1987
________ USACOE Project Maps, 1986
_________ Federal Highway Admin., 1985
MWRA STFP VL, 1987
............. Third Harbor Tunnel Dredging 1991 — 1992
.. U.S. Army Corps of Engineers
Improvement Dredging 1988—1995
FIGURE D.3.a. COMMERCIAL NAVIGATIONAL RESOURCES
D- 1 Lj
LEGEND
Navigation Channels
Anchorage #2
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Bay is provided by two channels, the North Channel and the South Channel, which meet
at President Roads approximately one nautical mile east of Deer Island. The
President Roads channel serves port and pier facilities in Boston, Charlestown, East
Boston, South Boston, Everett, Chelsea, and Revere (Boston Shipping Assn. 1986).
The channel through Nantasket Roads serves the industrial waterfront of’ Quincy
including the former General Dynamics Shipyard now owned by MWRA. A single
designated anchorage area is used within the harbor, located west of Deer Island,
and is used by 95 percent of connnercial shipping traffic requiring anchorage
(Figure D.3.a) (USACOE 1981 1). Designated anchorage buoys within the anchorage area
are used by ships waiting for harbor pilots (MWRA, WTFP 5, 1987).
Inner harbor improvement dredging is planned by U.S. Army Corps of Engineers in the
areas of the Reserved Channel in South Boston, Mystic River, and Chelsea River
(Figure D.3.a). This dredging is projected to begin in late 1989 and will take J4 to
18 months to complete (USACOE 1987). This project will produce approximately 2.3
million cubic yards of dredged materials (USACOE, 1988). This material will be
disposed of at the Foul Area Disposal Site (FADS) after being transported through
President Roads. The FADS is a U.S. EPA interim designated dredged material
disposal site located approximately fifteen miles east of Nahant. Additional
dredging amounting to approximately one million cubic yards is anticipated for the
Third Harbor Tunnel/Central Artery project (Federal Highway Admin. 1985). This
dredging will take place across the main channel from the Pier 6 area to Jeffries
Cove (Figure D.3.a). Scheduling of dredging and other disruptions to navigation
caused by the tunnel construction is not complete, though it is anticipated that 46
days of dredging and 9 months of tunnel section placement will be required during
1991—1992 (MDPW 1988).
It is anticipated that the tunnel could be constructed without having to close more
than half of the 1200-foot shipping channel for extended periods of time, although
total closure of the channel for approximately 9 one-day periods, occurring
approximately one month apart, will be required for precision tunnel alignment
(Federal Highway Adinin., 1985). This could cause delay in shipping goods and cancel
personnel transport from downtown Boston and Revere Sugar to Deer Island. Marine
traffic generated by materials shipment and dredged materials disposal from the
D- 15
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Third Harbor Tunnel/Central Artery Project will peak in 1991 at 15 one-way barge
trips per day (Ware, 1988). Destinations for materials delivery include sites near
North Station, Fort Point Channel, Reserved Channel, and Bird Island Flats. Third
Harbor Tunnel/Central Artery dredged and excavated material disposal is being
considered at FADS, Spectacle Island, and upland landfills.
D.3.1.2 Shipping and Water Transportation
Commercial cargo ships, tankers, passenger liners, local passenger ferries, and
sightseeing craft all operate within Boston Harbor and Massachusetts Bay.
Table D.3.a shows a historical record of commercial vessels using the Port of
Boston. Vessel records indicate that 6899 vessels entered the harbor in 1985. Only
633 of the 6899 vessels landed at Weymouth Fore River (Quincy) destinations,
traveling through Nantasket Roads and the Weymouth Fore River Channel (USACE
1986). The remaining 6266 vessels were bound for Boston Harbor, Chelsea River, and
Mystic River destinations, traveling through President Roads.
The figures above include all commercial vessels. For large commercial vessels with
drafts greater than 18 feet, 911 vessels traveled through President Roads and 50
vessels traveled through Nantasket Roads in 1985 (USACE 1986). During 1986, the
following numbers and types of large vessels (draft greater than 18 ft) entered
Boston Harbor (MWRA, WTFP 8, 1987):
373 Tankers
1 Liquid Natural Gas Carrier
82 Bulk Carriers
215 Container Ships
85 General Cargo Ships
19 Passenger Liners
5 Freezer Ships (frozen fish)
2 Miscellaneous
TOTAL 782 Large Vessels
D- 16
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TABLE D.3.a
HIS1VRICAL RECORD OF TRIPS AND DRAFTS
OF VESSELS (INBOUND ONLY) USING THE PORT OF B( TON
NUMBER OF TRIPS PER YEAR
Draft
(Pt) 1985 19811 1983 1982 1981 1980 1979 1978 1977 1976 1975 1974 1973 1972
141 0 3 1 2 1
140 3 lj 3 1 2 5 20 30 19 12 15 15 18 16
39 7 5 2 14 20 26 110 36 1 41 1 11 25 56 1 41
38 24 23 16 18 17 25 56 29 36 58 31 45 32 39
37 29 22 13 17 142 21 143 29 55 45 143 1411 1 41 39
36 36 61 35 33 46 149 57 59 67 149 60 146 55 147
35 lii 61 1414 56 77 77 69 87 69 57 55 58 62 69
314 30 31 67 66 62 59 100 81 78 55 614 52 57 57
33 33 17 21 36 37 37 52 57 85 59 55 114 80 57
32 17 22 33 36 29 214 39 37 72 70 73 73 88 85
31 31 33 110 35 36 143 149 33 70 81 56 69 91 98
30 59 62 58 66 72 39 113 118 119 46 51 77 65 55
29 31 51 73 67 711 58 143 31 37 142 36 115 78 ‘114
28 47 45 118 71 714 76 67 56 73 50 52 55 60 62
27 76 61 62 104 82 74 101 90 914 70 70 91 95 72
26 66 49 61 75 81 79 99 105 101 1011 814 98 96 103
25 97 65 40 72 54 57 73 92 56 79 72 85 88 97
211 55 148 80 75 69 76 70 80 54 95 95 80 76 95
23 65 63 51 76 71 58 47 39 140 119 69 63 85 118
22 75 91 80 I7 ‘ 16 30 140 140 1411 148 58 75 78 118
21 65 79 31 35 13 36 32 51 37 43 50 143 75 83
20 56 64 71 56 34 36 44 38 25 45 144 119 82 66
19 65 42 41 52 57 l b 37 145 113 36 23 30 54 62
18 & 5,885 5,034 ‘4,936 5,050 7,592 7,157 8,2148 12,679 17,916 15,000 12,048 12,725 10,710 11,5113
Less
TOTAL 6,899 6,033 5,906 6,11414 8,671 8,176 9,1155 13,876 19,156 16,237 13,246 13,989 12,223 13,066
Source: USACOE 1986 and Previous Editions; USACOE, 1987
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The total of 782 large ships entering and leaving the harbor in 1986 amounts to 15614
large vessel trips per year, or a daily average of 1 vessel trips per day
(MWRA, WTFP 8, 1987). As in 1985, almost all of the vessels passed through
President Roads.
The vessel trip numbers (Table D.3.a) indicate relatively small annual increases
recently in activity in terms of vessel trips for the Port of Boston. Tonnage of
cargo landed has varied in recent years but generally declined from 1970 to 1985,
then increased in 1986 due to larger. vessels being handled (Table D.3.b). Cargo
vessels calling at Massport facilities during the first six months of 1987 totalled
265, representing a six percent increase in the number of vessels over the same
months of 1986 (Massport 1987b). Commercial vessel traffic associated with the Port
of Boston is expected to remain stable or increase slightly during the next decade
(USACOE, 1987).
Local sightseeing cruises and passenger ferry services operate from piers on the
downtown Boston waterfront to destinations at Logan Airport, Hull, Hingham, the
Boston Harbor Islands State Park (seasonal) and whale-watching destinations
(seasonal). A recent Massachusetts Division of Marine Fisheries survey indicates
that the commercial fishing fleet berthed in Boston Harbor consists of 78 dragger
and gilinet vessels harvesting finfish, 1 vessel harvesting sea clams, and 127
inshore lobster boats (MDMF, 1987). Fish and shellfish are off-loaded and sold at
at several harbor locations including the Boston Fish Pier in South Boston where
they are auctioned (Massport 1987a). Lobster are off-loaded at a variety of piers
in Boston where they are sold to dealers.
The three largest Boston Harbor shipping terminals are operated by Massport. The
Harbor Gateway terminal in South Boston handles mostly bulk commodities,
automobiles, and cruise ship passengers. The Moran Container Terminal, located on
the Mystic River in Charlestown, handles containerized cargo. The Conley Terminal
in South Boston handles containerized cargo, lumber, and automobiles. Petroleum
products are handled at a variety of private terminals along the Mystic and Charles
Rivers and at the Quincy waterfront on the Weymouth Fore River.
Typical routes traveled by commercial vessels and local passenger ferries are shown
on Figure D.3.b.
D- 18
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TABLE D.3.b
COMPARATIVE STATEMENT OF COMMERCE
BOSTON HARBOR, MASSACHUSETTS
Year Short Tons
1986 25,900,000
1985 17,268,816
198L1 19,888,675
1983 12,036,1e78
1982 17,593,627
1981 20,306,’ 5O
1980 22,033,922
1979 26,3 I2,672
1978 26,073,590
1977 25,975,275
1976 25,172, 2
1975 2L1,719,1452
19714 25,728,9145
1973 27,056,868
1972 26,1483, 38
1971 26,156,517
1970 26,867,918
1969 2’4,610,760
1968 22,610,760
1967 21,5Z 9,086
Source: USACOE 1986 and Previous Editions; USACOE 1987
D- 19
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— Commercial Vessels
Source: Boston Harbor Islands State Park 1986
Master Plan, Mass Dept. of Environmental Management
Massport, 1987 B, Boston Shipping Association, 1986
—. —. —•— Boston Harbor Island State Park Ferries (Projected and Existing)
Commuter Service and Logan Shuttle
FIGURE D.3.b. TYPICAL COMMERCIAL AND PASSENGER SHIP ROUTES
D-20
LEGEND
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D.3.1.3 Co ercial Fishing
Commercial fisheries play an important role in the Boston Harbor region’s economy as
underlined by the recent $19 million dollar modernization of the Boston Fish Pier
(Massport 1987a). However, local fishing industries are faced with a myriad of
problems, most prominent being pollution and associated fish and shellfish
contamination, excessive fishing, and habitat loss and degradation (MDMF 1985). The
state’s most valuable commercial fishery is the lobster fishery. In greater Boston
Harbor, lobstermen hauled over 14 million pounds of lobster with a market value
exceeding $10 million-in 1986 (MDMF 1987). Yet, the effects of excessive fishing in
Massachusetts coastal waters since 1981 have resulted in depressed average size and
reduction in the proportion of females allowed to spawn (MDMF, 1987). Harvest of
17.5 million pounds of commercial finfish occurred in the project area and were
landed at Boston in 1986. However, National Marine Fisheries Service (NMFS) figures
indicate a constant downward trend in landings of important commercial fish: cod
down 514 percent since 1978; winter flounder down 146 percent since 1978; and yellow
tail flounder down 61 percent since 1979(MDMF 1985). In 1986, 38,529 bushels of
soft-shell clams were gathered from the Boston Harbor area, purified to remove
contaminants, and sold (MWRA, WTFP Vc, 1987). However, since 19811 over half the
Harbor’s shellfish beds have been closed due to pollution resulting in an estimated
loss of $14 million in annual commercial value (USEPA 1985).
Shellfish and finfish resources occur within Boston Harbor and Massachusetts Bay.
However, commercial harvest of finfish in the harbor is prohibited and shelifishing
is regulated (Figure D.3.c). The principal bivalve commercially harvested from the
5000 acres of shellfish beds is the soft-shell clam (Mya arenaria). Limited mussel
(Mytilus edulis) and hard-shell clam (Mercenaria mercenaria) harvesting also takes
place (MWRA, STFP V, 1987; MDC, 1981 1). Unacceptable levels of’ coliform bacteria
have caused closure of roughly half of the existing shellfish beds in Boston Harbor,
and harvest of the remaining half is limited to licensed Master Diggers. Harvest is
limited by the maximum capacity of the Newburyport depuration plant where all Boston
harbor shellfish must be decontaminated before being consumed.
Lobster fishing takes place throughout the Harbor and Massachusetts Bay. Lobster
fishing is generally concentrated inside the harbor in summer and outside the harbor
D-2 1
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in fall and winter (MWRA, STFP V,L, 1987; MDC 1981 ). Winter flounder
(Pseudopleuronectes americanus), yellowtail flounder (Limanda ferruginea) and cod
(Gadhus morhua) are the major finfish commercially harvested in the study area, but
only recreational fishing is allowed inside Boston Harbor (MWRA, STFP V,L, 1987).
Virtually the entire study area east of a line from Deer Island to Hull is a
commercial fishing ground (MWRA, STFP V,B, 1987; MDC 198 1 U. The area around the
proposed outfall sites is part of the exempted fishing area where nets with mesh
smaller than 5 inches (normal regulated mesh) are allowed by permit for harvest of
shrimp, whiting, Atlantic herring and mackerel. Using normal 5-inch mesh, cod,
haddock, pollock, -redfish, American plaice, yellowtail flounder, winter flounder,
and witch flounder may not exceed 10 percent of total catch while a vessel is in the
exempted area (MWRA, STFP V,C, 1987).
Intensive trawling for winter flounder has been reported around outfall Site 2
during the month of January (MDMF, 1988). This area occurs landward of the
Massachusetts Division of Marine Fisheries (MDMF) spawning closure and three mile
trawl closure lines (Figure D.3.c), and therefore is closed to trawling through the
remainder of the year. The spawning closure was designed to protect the majority of
spawning winter flounder that primarily use inshore areas of Massachusetts Bay from
January through May. Seaward of the spawning closure line, dragging potentially
occurs almost anywhere, except where restricted by seasonal closures within the
three-mile limit, large areas of unsuitable bottom, and areas where conflict with
stationary lobster gear occurs (during summer and fall). The smaller draggers tend
to favor the areas between outfall Sites 1 and 5 and an area 2-3 miles south, just
east of the Brewster Islands (MDMF, 1988). Both of these areas straddle the 3-mile
seasonal trawl closure line so that the landward portions are open only during
January through March (Site 10, whereas the seaward portions are fished all year
(Site 5). The MDMF has indicated that catch landings information is not fine enough
to differentiate among alternative outfall sites (MDMF, 1988).
Other commercial fishing activities in Massachusetts Bay include gillnet and purse
seine fisheries. The gilinetters work inshore of the three-mile limit (hence in the
project area) from mid-December through late spring on hard bottom areas avoided by
the draggers. Principal target species include cod, pollock, winter flounder, and
D-22
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LEGEND
98 Approximate Number of Lobster Buoys 7/27179
Shellfish Beds Closed to All Diggers
(Closure Varies wlConditions)
—— Shellfish Beds Restricted to Master Diggers
FIGURE D.3.c. COMMERCIAL FISHING RESOURCES
D—23
IENGHAM _________________________
Sources: Metcalf & Eddy, 1984
MWRA Vol. V App. L, 1987
MWRA Vol. V App. B, 1987
MDMF, 1988
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yellowtail. Some species move offshore by the summer and fall seasons. Purse
seining for Atlantic herring (Clupea harengus) and Atlantic menhaden (Brevoortia
tyrannus) also occurs in the western Massachusetts Bay area. Herring are caught
during the late fall and winter and are exported as sardines out of the Boston area,
principally to Maine. Menhaden are caught in the late spring and summer and are
principally processed for oils, animal food, or used as lobster or tuna bait.
NMFS data indicates that the statistical zone (number 5114), a large area which
includes the proposed outfall and diffuser locations, provides in excess of 17
million pounds of commercially harvested fish annually (MWRA, STFP V,K, 1987; !JMFS,
1987). Statistical zone 5114 covers approximately 1400 square miles.
D.3.1.14 Recreation Areas and Facilities
Recreational resources in Boston Harbor and Massachusetts Bay include shoreline and
island parks and beaches, diving areas, recreational boating facilities,
recreational fishing areas, and sightseeing and whale watching vessel piers.
Location, ownership, and facilities available at beaches and parks within the study
area are reported in MWRA, STFP, Vol. V, L, 1987. Figure D.3.d displays locations
of beaches and parks within the study area. More than 100 recreational beaches and
parks and 150 support facilities for recreational boating are present in Boston
Harbor and Massachusetts Bay from Lynn to Scituate (MWRA, STFP V,L, 1987).
Boston Harbor Islands State Park encompasses many islands with varying recreational
opportunities and facilities. Table D.3.c lists the islands included in the park
system and the facilities available to each island. Figure D.3.d displays the
location of the islands included in the State Park and shows the operating and
planned routes which passenger ferries will travel to bring visitors to the
islands. The Commonwealth of Massachusetts has authorized a $7 million bond issue
to build a visitors center on Long Wharf in downtown Boston, which will serve as a
central embarkation point for the majority of Boston Harbor Islands visitors (USEPA,
19814). The Harbor Islands can also be reached by private pleasure craft.
D 2LI
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Recreational Beaches
Boston Harbor Island State Park
• Other Parks
Harbor Islands Ferries (Proposed)
FIGURE D.3.d. BEACHES, SHOREUNE PARKS, AND ISLAND PARKS
D-25
LEGEND Source: Boston Harbor Islands State Park
1986 Master Plan—Mass. Dem
MDC, 1984
MWRA, VOL. V, App. L, 1987
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TABLE D.3.c. BOSTON HARBOR ISLANDS STATE PARK
Location Ownership Location Facilities
Bumpkin Island DEM Hingham Bay Ferry Service, docking (pier)
facilities, camping, pit
toilets, picnic areas, trails,
historic remains
Calf Island DEM Outer Harbor Day use, foot trails, old
building remains
Castle Island MDC Dorchester Bay Tours of Ft. Independence,
picnic areas, fishing pier,
comfort stations, children’s
play area, walkways
Deer Island MDC Dorchester Bay Tours of sewage treatment plants
Gallops Island DEM Quincy Bay Ferry service, docking pier, pit
toilet, picnic areas, trails,
gazebo, beaches
Georges Island MDC Quincy Bay Day use, ferry service, docking
pier, toilets, picnic area
with grills, path around Ft.
Warren, tours, Info. Booth,
admin. building, chapel, first
aid station, concession (food
& souvenirs)
Grape Island DEM Hingham Bay Ferry service, docking pier,
camping, toilets, picnic
areas, trails, grape arbor
The Graves Outer Harbor Lighthouse
Great Brewster DEM OuterHarbor Camping, trails, pit toilet,
Island boating, pier for loading &
unloading only (no tie up),
picnic areas
(DEM = Department of Environmental Management, MDC = Metropolitan District
Commission) -
Source: MWRA, STFP, Vol V. App. L, 1987
USEPA, 198L1
D-26
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Access to the harbor and Massachusetts Bay for recreational boaters is provided by
public and private boat launching ramps, marinas, and yacht clubs. Major public
access points and facilities are shown in Figure D.3.e. Baseline information on
recreation has been gathered and Is included as part of the SDEIS on Boston Harbor
wastewater facilities siting (USEPA, 19814).
Recreational fishing takes place in the harbor and throughout the Massachusetts Bay
area. Most anglers utilize their own boats, lease boats, or use the available party
boats and charters based in the area. Recreational party boat fishing takes place
in- Massachusetts Bay including the outfall area and 6 boats are berthed in Boston
Harbor (MDMF, 1987; MDMF, 1988). The recreational fishing industry in the Boston
area once thrived but has been depressed in recent years because of the negative
publicity on harbor pollution and contaminated or cancerous fish.
Recreational fishing activity generally occurs from spring through fall with peaks
during the summer vacation months when anglers from Connecticut, New York, New
Jersey, and Pennsylvania come to the area. The Massachusetts Division of Marine
Fisheries (MDMF 1988) has indicated that this activity occurs at all candidate
outfall sites. However, the most popular areas are located inshore of Site 2 or at
the “B” buoy located about one mile south of Site 5. Other popular areas include
the Harbor Islands, Graves Light, Boston Light, and the Three and One-Half Fathom
Ledge.
The most popular target species include winter flounder, cod, mackerel, and
bluefish. In general, flounder are caught in the inshore areas from May through
September; cod throughout Massachusetts Bay during spring and fall; mackerel in
inshore areas (Sites 2 and 14) during spring and early summer and offshore areas
(Site 5 and seaward) during the fall; bluefish at the offshore sites from June
through August and inshore sites from July through September. Other species of
interest include pollock, woiffish, conger eel, dogfish, and silver hake. Tuna are
also caught in eastern Massachusetts Bay by larger party boats and charter boats.
D-27
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• Marinas w/more than 50 Slips or Moorings
* Boat Ramps
o Facilities w/more than 50 Slips or Moorings
and Boat Ramps
Source: Boating Almanac 1986
FIGURE D.3.e. MAJOR BOATING PUBLIC ACCESS POINT
D-28
LEGEND
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D.3.1.5 Sensitive and Protected Areas
Harbor resources which are particularly sensitive to environmental damage are
identified below and given particular attention in Section D. 4, Environmental
Consequences. Harbor resources are considered sensitive if anticipated potential
impacts of the construction and operation of the inter-island conveyance and
effluent outfall could cause significant irreparable damage to the resource or cause
immediate danger to public health. Each sensitive Harbor resource is described
below, along with the reasons for its sensitivity.
D.3.1.5.1 Bathing Beaches are deemed sensitive because any contamination from
effluent or spills of fuel or chemicals from vessels could have immediate adverse
effects on public health. Locations of the major bathing beaches in the potentially
affected area are shown on Figure D.3.d.
D.3.1.5.2 Shellfish Beds, like bathing beaches, are deemed sensitive because
contamination could adversely affect public health if contaminated shellfish are
harvested and consumed. Contamination could also cause economic and environmental
impacts if the vigor and reproductive capabilities of shellfish populations were
affected or if additional shellfish beds had to be closed to harvest. Existing
shellfish beds in Boston Harbor are mapped on Figure D.3.c. All Boston Harbor
shellfish beds are closed or restricted. However, this Draft SEIS will evaluate
them as if they were open since this would probably be true in the future when the
Harbor clean-up is well underway.
D.3.1.5.3 Marine Research Facilities are considered sensitive resources because
ongoing research could be adversely affected if sea water supply to laboratories and
aquariums became more contaminated than at present or if contamination reached
existing ecological field plots. Two facilities exist in the study area, the New
England Aquarium in Boston and the Northeastern University Marine Lab in Nahant
(Figure D.3.f).
D.3.1.5.k Estuarine and Submerged Aquatic Vegetation are included as sensitive
resources because contamination or physical disruption could cause long-term adverse
impacts on the Boston Harbor ecosystem by diminishing areas of primary productivity
D-29
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LEGEND
Saltmarsh
j,-ç Significant Identified areas of
L±i - Submerged Vegetation
Areas of Critical
Environmental Concern
___________ South Essex Ocean Sanctuary
• Marine Research Facilities
Sources: MWRA Vol. V, APP.L, 1987
BARR, 1987
(Shellfish Beds Shown on Figure E).3.c)
(Bathing Beaches Shown on Figure U.3.d.)
FIGURE D.3.f. SENSITIVE HARBOR RESOURCES
)
//
‘ ------4
/
SITE 5 Potential
S Diffuser
Sites
Georges
C) Island
OWNCY
NAUTICAl. MILES
D-30
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and breeding. Estuarine and submerged aquatic vegetation areas have already been
greatly reduced by development along the shore of Boston Harbor, increasing the
value of the remaining areas. Existing saltmarshes and submerged vegetation are
shown on Figure D.3.f.
D.31.5.5 Sanctuaries and Areas of Critical Environmental Concern are areas which
have been protected by the Commonwealth of Massachusetts because of their unique
ecological values. The areas within the study area are protected because of their
ecological and aesthetic value as saltmarsh and shoreline environments. The South
Essex Ocean Sanctuary and Areas of Critical Environmental Concern on the Back River
and Weir River lie within the study area (Figure D.3.f). Boston Harbor Islands
State Park is also a protected natural and recreational resource (Figure D.3.d).
D.3.1.6 Cultural and Archaeological Resources
Cultural and archaeological resource sites are located throughout Boston Harbor,
Massachusetts Bay, and the surrounding shoreline. Only those resources potentially
affected by the outfall and inter—island conduit construction and operation are
described.
Cultural and archaeological resources potentially impacted by outfall and diffuser
construction consist of shipwrecks in the vicinity of the diffuser sites. The
outfall tunnel would not impact any cultural or archaeological resources because it
will pass through rock below the ocean floor, but drilling or trenching for the
diffuser could cause obvious disruption of wrecksites. A recent review of cultural
and archaeological resources performed for MWRA (MWRA, STFP V, FF, 1987) indicated
potential shipwreck sites in the vicinity of’ alternative diffuser locations.
Shipwreck locations were developed from historic records and have not been field
verified. The recorded locations of shipwrecks indicate a greater potential
occurrence of wrecks closer to shore. However, historic records of shipwrecks are
thought to be incomplete and locations reported are not thought to be precise.
About one third of the known shipwrecks identified in the diffuser area date from
1919 to 1950. Wrecks predating World War I are possible but are not recorded. The
general locations of recorded wrecks are shown by Figure D.3.g.
D-31
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t oi’Os
si ALL
SOURCE: MWRA VOL. V APP. FF 1987
FIG tJR.E D.3.g. SHIPWRECKS WITHIN 1.5 MILES OF CANDIDATE OUTFALL SITES
(ShIP NAMES INI)ICATE APPROXIMATE LOCATIONS)
BEACH
ARCO #8(1950)
8R040 SOL/Nt.
UNIDENT IFIED
LEIGH # 3(1919)
U i
I’)
ROMANCE
(1936)
UNIDE NT IF D
UNIDENTIFIED
WINIFRED SHERIDAN
(PRE-WW a)
Y U S. 14 (1945)
UNIDENTIFIED
CITY OF SALISBURY
(1938)
DEER
ISI. AND
NUMBER IS (1927)
SOUTH
BOSTON
UNIDENTIFIED
Nr
PRESIDE
Oc
LOVELL
ISLAND
if
LONG
ISLAND
c GEORGES
ISLAND
LEGEND
• CANDIDATE OUTFALL SITES
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D.J ENVIRONMENTAL CONSEQUENCES OF THE PROJECT
This section relates harbor resources to the potential environmental consequences
resulting from the construction and operation of the inter-island conduit and the
effluent outfall. Impacts presented provide comparison among outfall locations
(Sites 2, L and 5) and two diffuser designs (drilled riser and dredged trench). The
only construction option considered for the effluent and inter-island conduit is
deep rock tunnel construction.
As demonstrated in Appendix A, a major consideration in determining impacts on
harbor resources is the fact that modeling results have shown that water quality in
the harbor will not be significantly impacted. Subsequently, operation of the
effluent outfall and conduit will have negligible effect on the harbor, with impacts
limited to the transport of operations workers and materials. As discussed in
D. 1 L5, operation impacts on resources outside the harbor may occur. The inter-
island conduit does not open to the harbor, and therefore cannot impact harbor
resources.
Construction-related marine traffic is the major cause of adverse impacts inside the
harbor. Since the marine traffic traffic generated by construction of all the
outfall alternatives is proportional to outfall length and the rate of outfall
tunnel boring is the same for all lengths, in-harbor impacts of the alternatives are
similar in nature for all alternative sites, but longer in duration for sites
farther offshore.
D. 1 l.1 NAVIGATION
Based upon screening results (Draft SEIS Chapter 3; Appendix F), the only
construction method being considered for both the inter-island conduit and the
effluent outfall tunnel will be deep rock tunneling using either a tunnel boring
machine or drill and blast methods. Since the inter-island conduit and the effluent
outfall will be constructed below the sea floor, the only effects on navigation in
Boston Harbor and along the approaches to the harbor would be caused by increases in
marine traffic resulting from the project (Section D. 1 L2). Construction,
disregarding marine traffic impacts, is not anticipated to cause significant
D-33
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barriers to navigation, alterations to existing channels or routes, or disruption of
planned navigational dredging. Effluent plume surfacing will not interfere with
marine traffic in the area. The construction of any of the pier alternatives
proposed for Deer Island will narrow the passage between Deer Island and the
anchorage, but the remaining channel width is expected to offer minimal interference
with marine traffic (MWRA, WTFP 7, 1987). This impact would be identical for all
outfall site locations.
Capacity of the port facilities utilized by the commercial shipping industry will
not be affected because new on-shore facilities will be constructed for project use
(MWRA, WTFP 5, 1987). These facilities are to be constructed at sites not currently
used for commercial shipping.
Temporary disruption of navigation may occur as a result of the construction of the
Third Harbor Tunnel, which will likely constrict the channel to the Inner Harbor for
a period of approximately 9 months during 1991-1992 and will completely close the
channel for 9 one-day periods spread over 9 months (Federal Highway Admin., 1985).
Constriction of the channel would not be a consequence of conduit and outfall
construction, but will affect the marine traffic in the channel which will be
increased by personnel ferries, barges, and supply boats traveling to Deer Island
from the Revere Sugar Site and the Boston waterfront. This additional traffic may
exacerbate the situation to the point where marine traffic delays are encountered by
vessels attempting to pass through the channel at the Third Harbor Tunnel site. In
any event, schedules for movement of’ materials and personnel to and from the Revere
Sugar Site and Boston to Deer Island should reflect the possibility of
transportation delay to avoid delaying construction.
No impacts on navigation are anticipated from the operation of the inter-island
conduit or the effluent outfall. The water depth at all of the potential outfall
locations is sufficient to ensure that even deep draft vessels are in no danger of
colliding with diffuser risers, and the amount of particulate matter deposited by
the outfall is not great enough to cause shoaling.
D-3 1 1
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D.iI.2 SHIPPING AND WATER TRANSPORTATION
Marine traffic in Boston Harbor and Massachusetts Bay will increase significantly as
a result of this project during construction, and to a lesser extent, operations.
The increase will be exacerbated by the simultaneous construction of the Third
Harbor Tunnel/Central Artery project. Most non-project traffic and almost all
project traffic will pass through or cross the channel at President Roads near Deer
Island.
To determine if marine traffic will experience significant adverse impact in the
form of delay, peak daily marine traffic volumes for all Deer Island Treatment Plant
related marine traffic plus Third Harbor Tunnel/Central Artery related traffic were
compared to volumes from 1977. Harbor traffic levels in 1977 were the highest for
the last 15 years (Table D.3.a). This comparison is illustrated by Figure D.LLa.
Projections for peak marine traffic were calculated by adding peak project-related
traffic (Deer Island Treatment Plant, conduit and outfall, and Third Harbor
Tunnel/Central Artery) to 1985 non-project commercial traffic (cargo and passengers
from USACOE Records) (USACOE, 1986). This represents a worst case for the following
reasons:
• Treatment plant-related traffic volume used in Figure D. La assumes that
only small supply boats would be used, totalling 118 trips per day, the
highest number of trips of all vessel options under consideration. It is
likely that large ferries or barges would be used as opposed to supply
boats, resulting in 2 4 large ferry trips or 8 barge trips per day.
• Peaks for all project—related traffic were assumed to take place
simultaneously. It is likely that peak treatment plant traffic will
occur in 1992—1993 (MWRA WTFP 7, 1987) and peak Third Harbor
Tunnel/Central Artery marine traffic will occur in 1991 (Ware, 1988).
Projected volume of large vessel (greater than 18-foot draft) traffic is less than
levels experienced in 1977. Projected volume of vessels less than 18 feet in draft
is 25 percent higher than volumes experienced in 1977. Even in the worst case
D-35
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150
VESSELS GREATER THAN VESSELS LESS ThAN
18 FEET IN DRAFT 18 FEET IN DRAFT
AND
PASSENGERS
MARINE TRAFFIC IN 1985 PLUS PEAK HARBOR PROJECT TRAFFIC
(DEER ISLAND TREATMENT PLANT & 3RD HARBOR TUNNEL!
CENTRAL ARTERY)
1977 MARINE TRAFFIC
SOURCE: USCOE, 1986 AND PREVIOUS EDITIONS; USACOE, 1987;
WARE 1988; MWRA WTFP V, 1987
FIGURE D.4.a. PROJECTED PEAK BOSTON HARBOR MARINE TRAFFIC (1990-1995)
COMPARED TO MARINE TRAFFIC IN 1977
a
w
C D
w
a
w
0
C l )
C-
I -.
-J
w
Cl)
C,)
w
120
90
60
30
0
CARGO
AND
WORKERS
LESS THAN
1 (HARBOR
PROJECT)
D-36
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scenario described by Figure D.LL.a, traffic volumes are not significantly greater
than those experienced in the past.
Most of the increased traffic volume will use the President Roads channel southwest
of Deer Island. Vessels using the anchorage area west of Deer Island and vessels
traveling to and from the proposed project anchorage (north of the existing
anchorage area) will travel in the channel. Vessels carrying project personnel and
material from the Revere Sugar Site and the downtown Boston Waterfront will travel
in the channel, and vessels from the Quincy Shipyard site and south shore personnel
piers will cross the channel. Bulk materials shipped from points outside the harbor
will enter and leave through the President Roads channel.
MWRA reports that discussions with the Pilots Association, Boston Shipping
Association, and Boston Fuel Transport indicate that Boston Harbor is currently
busy, but not excessively crowded and that increases in traffic resulting from MWRA
construction should pose no significant problems to navigation (MWRA, WTFP 5,
1987). Currently, no formal marine traffic direction takes place in Boston Harbor,
though the harbormaster has the authority to institute traffic controls.
The situation is partially mitigated by the fact that the small ferries, supply
boats, and personnel boats MWRA plans to use are highly maneuverable compared to
larger vessels, and can operate in areas not accessible to deeper draft barges and
commercial ships. Should future congestion require further mitigation, such marine
traffic controls as establishing assigned channels or anchorages could be
instituted. The groundwork for marine traffic coordination exists in the form of an
interagency committee consisting of representatives from MWRA, Massport,
Massachusetts Division of Public Works, the Boston Harbormaster, and the U.S. Coast
Guard. The committee represents existing maritime interests and the major projects
scheduled for the harbor area.
The three alternative effluent outfall sites require different effluent tunnel
lengths, and therefore generate different amounts of tunnel excavate and vessel
trips to transport the excavate from Deer Island. The marine traffic levels used in
the worst case scenario include enough vessel trips to account for removal of the
excavate for a tunnel to Site 5 (1.9 million cubic yards) (MWRA, STFP V, 1987).
D-37
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Selection of Site 14 would require removal of 1.3 million cubic yards of material,
and Site 2 would generate 0.8 million cubic yards. Marine traffic would be greatest
for Site 5, less for Site L I, and least for Site 2. In the worst case, excavated
materials would only add approximately one barge trip per day to the construction
generated marine traffic.
Similarly, longer tunnel lengths require more concrete for tunnel lining, and
therefore more marine traffic delivering materials to Deer Island. Maximum tunnel
lengths are considered in the worst case scenario. Shorter tunnel lengths would
reduce traffic, but, as in the case of tunnel excavate, by only a small number of
vessel trips when compared to total construction traffic.
Excavated trench diffuser design would produce approximately 1.14 million cubic yards
of dredged material while a drilled riser diffuser would produce 12 thousand cubic
yards of excavate. Significantly greater numbers of vessel trips would be required
to dispose of trenched versus drilled materials (approximately 2 orders of magnitude
more trips), but these trips would likely be out of the harbor to the Foul Area
Disposal Site.
Few marine traffic impacts result from the inter-island conduit because most of the
excavated materials will be used on Deer Island during early site preparation and
treatment plant construction. Concrete materials for lining the conduit will likely
be delivered to Deer Island from Quincy or outside the harbor and are considered in
the worst-case scenario.
D. 1 I.3 COMMERCIAL FISHING
Disruption of commercial fishing within Boston Harbor is limited to possible
destruction or disturbance of lobster traps by vessels traveling through areas of
the harbor where lobsters are trapped. Most traffic in the harbor will be following
established channels. Since few lobster traps are set in the channels, traffic will
not significantly impact lobster fishing. Vessels potentially traveling outside the
channels will include ferries, small supply boats, and personnel vessels. All of
these vessels are maneuverable and can largely avoid lobster traps, thus impacts
will be negligible (MWRA, WTFP 7, 1987).
D-38
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Commercial finfishing is prohibited in the harbor, therefore no impacts on
finfishing in the harbor will occur. Shellfish harvest is permitted in some areas
of the harbor, but none of these areas will be affected by construction or
operation. The selection criteria for outfall location include a criterion which
assures that a site will not be chosen where effluent would be carried into the
harbor by tides or currents without adequate dilution to prevent significant
impacts. As a result the operation of the outfall will have no adverse effect on
commercial fishing in the harbor. Inter-island conduit construction takes place
below the harbor and does not affect fishing. No construction will occur in harbor
waters, thus no impact on recreational fishing in the harbor is anticipated.
The areas under consideration for outfall diffuser location all lie within active
finfishing grounds. Anticipated impacts on commercial fishing at the outfall
include disruption of fishing activities during construction of the diffuser, when
access to portions of the diffuser area will be precluded by the presence of
drilling or dredging equipment. During operation, the diffuser riser structures
will be obstacles which may foul or damage fishing nets. A drilled riser diffuser
presents less of an obstacle than a dredged trench diffuser. The drilled risers
would affect a small portion of the sea floor, with no disturbance between risers.
The dredged trench would be covered with armoring rock, presenting an obstacle to
commercial fishing along the entire diffuser length. Diffuser cap design should
seek to minimize interference with dragging activities which might continue in the
area.
Despite differences in seasonality at the various outfall sites, data available
regarding the intensity of commercial fishing does not allow significant
differentiation of commercial fishing impacts among sites 2,li, and 5. In general,
all sites are utilized for commercial fishing, therefore impacts for all three sites
are rated as moderate. However, the sites may differ in terms of potential
alteration of sensitive spawning habitat. As indicated in Section D.3.1.3, the
majority of the commercially important winter flounder spawn in the inshore areas of
Massachusetts Bay including Boston Harbor. Site 2 is located within the spawning
closure area imposed by MDMF to provide protection for the flounder spawn.
Placement of the outfall at Site 2 is more likely to result in adverse sedimentation
impacts on sensitive demersal flounder eggs, especially during the interim primary
D-39
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period, and possibly impair or reduce reproductive success. A lesser impact is
anticipated at Site i4 and Site 5, because less flounder spawning probably occurs at
these sites and the impact areas are projected to be smaller (Appendices B and C).
D.I$. 1 RECREATION
All of the aforementioned recreational resources lie within the harbor with the
exception of some North and South Shore recreational beaches and water areas outside
the harbor used by boaters.
As demonstrated in the analysis of onshore transport of effluent during extreme
events (Appendix A), effluent concentrations on the beaches are projected to be
highest if the discharge is at Site 2. However, even the highest projected
concentrations are extremely minimal and will not impact recreational activities.
Adverse impacts on Boston Harbor recreational resources are not expected from a
discharge at any of the sites. Similarly effluent discharged from any of the sites
will not be directly transported into the Harbor. Therefore, the recreational value
of the Harbor should be generally the same or much improved over present conditions
by discharge at any of the sites.
Outfall and conduit construction will not affect recreational resources because
construction will take place in rock below the sea floor. Construction-related
traffic will have some effect on recreational boating, sightseeing vessels, and
harbor island ferries by increasing congestion in the harbor. However, differences
in harbor traffic among the various siting and design options are not great enough
to cause different recreational boating impacts. Operation could affect
recreational boating by having negative impacts on the aesthetics at outfall areas
in the form of occasional effluent plume surfacing. Site 2 would have the greatest
chance of the plume surfacing, Site l a moderate chance, and Site 5 a small chance
(MWRA STFP VB, 1987).
D-LIO
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Recreational fishing may also be affected by increased congestion in the harbor
because construction traffic may interfere with recreational fishing boats. As
indicated in Section D.3.1.LI, recreational fishing does occur at all outfall
locations. However, recreational fishing activity is more intense landward of
Site 2 and at popular areas such as the “B” buoy, the Graves, and Boston Light, all
of which are outside any projected impact zone for any of the outfall locations.
Thus, impacts for all three outfall locations are equal and can be rated as minor.
D.J4.5 SENSITIVE AND PROTECTED AREAS
No significant impacts on any of the sensitive resources described earlier are
expected. Other than at the areas already mentioned in Section D.ZLLI, effluent will
not reach any of these resources (Appendix A), so operations impacts are non-
existent. Construction impacts are limited to possible increased turbulence by
marine traffic affecting saltmarshes and submerged vegetation. This potential Is
greatest for nearshore (Site 2) and least for offshore (Site 5). However, the
impacts should be minimal and temporary at any site.
D.q.6 CULTURAL AND ARCHAEOLOGICAL RESOURCES
Impacts on cultural and archaeological resources are limited to the area around the
effluent outfall, where artifacts (shipwrecks) could be disturbed by dredging
trenches or drilling riser shafts. The density of potential wrecksites decreases
from southwest to northeast along the line formed by the alternative outfall sites
(MWRA, STFP V,L, 1987). Site 5 has the least chance of containing a wrecksite, Site
a moderate chance, and Site 2 a good chance (MWRA STFP VB, 1987). Because of the
larger amount of sea floor it disturbs, dredged trench diffuser construction has a
greater chance of adverse impact than drilled risers. Detailed site-specific
investigations are required to define the exact location of wrecks, and to formulate
avoidance or mitigation plans. It is anticipated that wrecksites can be avoided by
adjusting diffuser riser locations or mitigated through recovery or documentation of
resources In accordance with State and Federal requirements.
D_LI 1
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D.1I.7 CONCLUSION
Outfall location affects marine traffic levels, with Sites 2, 1 , and 5 producing
more traffic, respectively. Dredged trench diffused construction generates more
marine traffic than drilled risers. Interference with commercial fishing activities
are anticipated to be equal among all sites, with impacts of excavated trench
diffuser construction being greater than those for drilled risers. Recreational
impacts are most likely to result from diffuser location at Site 2, moderate at Site
$, and Ieastat Site 5. No significant impacts on sensitive and protected areas are
anticipated. Archaeological impacts are least likely at Site 5, moderate at Site ,
and most likely at Site 2, with dredged trench diffuser construction having a
greater chance of impact than drilled risers. Considering all harbor resource
impacts, Site 5 with drilled riser diffuser produces the lowest impact, with a small
increase in marine traffic being outweighed by less impact on commercial fishing,
recreation, and archaeological resources (Table D.ZLa).
D- 1 42
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TABLE D. 1 1.a COMPARISON OF HARBOR RESOURCES IMPACTS FOR EACH DIFFUSER SITE
Relative Severity of ImDacts
Site 11
Site 5
Navigation
Shipping and Water Transportation
Commercial Fishing
Drilled Risers
Dredged Trench
Protection of Commercially
Important Species
Recreation
General Study Area
Outfall Area
(Boating)
Sensitive and Protected Areas
Cultural and Archaeological
Resources
Dredged Trench
Drilled Riser
Low Low
Slightly Moderate
Less Than
Moderate
Low Low
Moderate Moderate
Moderate Low
Low Low
Moderate Low
Minimal Minimal
High Moderate
Less than Moderate Moderate
Category of
Impact Site 2
5 1
Low
Slightly
Greater Than
Moderate
Low
Moderate
Low
Low
Low
Mi n iinal
Low
Less than Moderate
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REFERENCES
Boston Shipping Association, Inc. 1986. The Port of Boston Handbook. Boston,
Massachusetts.
Federal Highway Administration, 1985. Final Environment Impact Statement and Final
Section ‘4(f) Evaluation: Third Harbor Tunnel, Interstate 90/Central Artery,
Interstate 93. Vol. 1 (Massachusetts Department of Public Works).
Massport, 1987a. Year End Report: 1986 Port of Boston Report.
Massport, 1987b. Port of Boston - Six Month General Cargo Report: January to June
1987.
Massport, Undated. The Port of Boston: New England’s International Gateway.
MDC, 198 ’L Application for a Waiver of Secondary Treatment for the Nut and Deer
Island Treatment Plants, Commonwealth of Massachusetts, Metropolitan District
commission.
MDMF, 1985. Massachusetts Marine Fisheries Assessment at Mid Decade. Massachusetts
Division of Marine Fisheries.
MDMF, 1987. Massachusetts Lobster Fishery Statistics, Massachusetts Division of
Marine Fisheries.
MDMF, 1988. Personal Communication with Robert Bruce and Michael Hickey
Massachusetts Division of Marine Fisheries.
MDPW, 1988. Personal Communication with John Coil, Massachusetts Executive Office
of Transportation and Construction, Division of Public Works.
MWRA, WTFP Revere, 1987. Water Transportation Facilities Plan, Revere Sugar Site
Evaluation, Charles town, Massachusetts.
MWRA, WTFP 1, 1987. On—Island Water Transportation Facilities for Deer Island and
Nut Island, Final Engineering Report — Volume 1.
MWRA, WTFP 5, 1987. Final Environmental Impact Report. Vol. 5, On Shore Water
Transportation Facilities.
MWRA, WTFP 5, 1987. On Shore Water Transportation Facilities, Transport of
Construction Materials, Transport of Construction Materials, Equipment, and
Operations Supplies. Final Environmental Impact Report - Volume 5.
MWRA VC, 1987. Deer Island Secondary Treatment Facilities Plan, Volume V, Appendix
C, Public Health Risk Assessment.
D- ’ 4i4
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REFERENCES (Continued)
MWRA, WTFP 7, 1987. On-Island Water Transportation Facilities for Deer Island and
Nut Island, Facilities Plan and Environmental Information Document. Volume 7.
MWRA, STFP VL, 1987. Secondary Treatment Facilities Plan, Volume V, Appendix L,
Resource Mapping.
MWRA, STFP VFF, 1987. Secondary Treatment Facilities Plan, Volume V, Appendix FF,
Marine Archaeology.
MWRA, STFP VB, 1987. Secondary Treatment Facilities Plan, Volume V, Appendix B,
Chemical and Biological Oceanography.
MWRA, STFP XK, 1987. Secondary Treatment Facilities Plan, Volume V, Appendix K,
Fisheries Landings.
NMFS, 1987. National Marine Fisheries Service Database: Commercial Fisheries
Statistics, January - December, 1986.
USACOE, 1988. Personal Communications with Carl Boutilier, US Army Corps of
Engineers, New England Division.
USACOE, 1987. Personal Communication with Mark Habel. U.S. Army Corps of
Engineers, New England Division.
USACOE, 198l4. Environmental Assessment Maintenance Dredging of Boston Harbor,
Boston Massachusetts. U.S. Army Corps of Engineers, New England Division
USACOE, 1986. Waterborne Commerce of the United States. U.S. Army Corps of
Engineers.
U.S. EPA, 19811. Recreation and Visual Quality Baseline for the SDEIS on Boston
Harbor Wastewater Facilities Siting.
U.S. EPA, 1985. Final Environmental Impact Statement, Siting of Wastewater
Treatment Facilities for Boston Harbor, Volume I, Comprehensive Summary. U.S.
Environmental Protection Agency Region I.
Wane, 1988. Personal Communication with Ken Ware, Bechtel/Parsons-Brinkerhoff,
Boston, MA.
D- 1 15
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APPENDIX E
ECONOMIC IMPACTS
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APPENDIX E
ECONOMIC IMPACTS
The purpose of this appendix is to estimate the impact on representative users of
financing the construction and operation of the new MWRA wastewater treatment plant
and related facilities. The increase in sewer user costs is estimated separately
for each of the three outfall alternatives. The communities of Needham and Boston
are used here as they were by MWRA to evaluate impacts (MWRA, STFP, VII, 1987). A
comparison of costs of the MWRA system versus costs nationwide is also presented.
A complete review of the financial impacts of the new treatment facilities on the
MWRA’s cash flow requirements was completed during the Secondary Treatment
Facilities Plan (MWRA, STFP VII, 1987). The information developed during the STFP
is used as a base for the calculations in this appendix.
E. 1 MWRA CURRENT REVENUE SYSTEM
The construction of the new wastewater treatment plant, outfalls and related
facilities involved in cleaning up Boston Harbor requires a large financial
commitment. Operation and maintenance of the MWRA facilities, once they are
constructed,\will require further commitment of funds. Costs for both construction
and operation and maintenance of the MWRA facilities could be recovered from various
grant and loan programs and assessments to the MWRA member communities. The member
communities would then pass the costs on to the individual users through sewer use
charges and/or property taxes depending on the type of recovery programs the
individual towns employ.
As a part of its current revenue system the MWRA charges the 143 member communities
for their use of the MWRA facilities. The communities are billed and then pass the
cost on to the individual users. The method the communities use to distribute the
costs vary. The MWRA is currently reviewing the methodology used to bill the
communities, and, as yet, has not agreed on how a new methodology should be
developed. Therefore, the current methodology of distribution of costs to the
member communities will be used for this analysis.
E-1
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E.2 FINANCIAL IMPACTS OF THE OUTFALL ALTERNATIVES
Three outfall locations have been selected for detailed consideration. These
locations, Site 2, Site Z and Site 5, are described in Appendix F, Screening of
Alternatives of this Draft SEIS. The characteristics of the selected outfall sites
are suim_narized in Table E.2.a. The purpose of this section is to determine what
impacts the varied outfall capital costs would have on the individual sewer user
charge. The cash flow analysis completed in the STFP is used to calculate capital
costs for each fiscal year for each of the outfall site locations.
During the STFP (MWRA, STFP VII, 1987), estimates of the MWRA capital expenditures,
operating expenditures, and revenue requirements were completed for the fiscal years
1987 to 2005. The estimates were made in terms of current and inflated dollars.
Review of the methodology and the estimates follows.
E.2.1 CAPITAL EXPENDITURES
During the Facilities Plan preparation, a review and projection of the capital and
operating expenditures of the MWRA to the year 2005 was made. Capital costs include
construction costs, engineering services and contingencies. Capital costs for all
facilities recommended in the STFP were included as well as for projects listed on
the MWRA’s 1988 Capital Improvements and other previously identified construction
projects. Estimates for capital costs associated with residuals management are
included.
For this appendix, it is assumed that the HWRA cost will be recovered based on
100 percent pass through of the cost to individual users. However, some MWRA
construction projects are included on the state Fl 1988 Fundable List. Projects
included on the list are likely to get a combined federal and state grant
reimbursement of 85 percent of the total cost. The projects on the Fl 1988 Fundable
List include:
E-2
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TABLE E.2.a SUMMARY OF SELECTED OUTFALL ALTERNATIVES
Outfall
Alternative
Tunnel
Inside
Diameter
(It)
Total
Tunnel
Length (1)
(It)
Start
Engineering
Award
Construction
Contract
Complete
Construction
(2)
Project
Cost (3)
(million
dollars)
Site 2
22
28,000
1/88
9/90
8/911
276
Site I l
21 1
113,000
1/88
9/90
12/911
389
Site 5
25
511,000
1/88
9/90
5/95
1468
1. Total tunnel length includes 6,600 ft of tunnel under the diffuser.
2. Construction completion date requires that the contract be awarded in the fall of 1990, mobilization occur over the
winter, and construction begin in the spring of 1991.
3. Project costs represent September 1986 dollars and include a 35-percent allowance for engineering and contingency
costs.
Source: Adapted MWRA, STFP V, 1987.
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• Early Site Preparation;
• On-Island Piers;
• Off—Island Piers;
• Wellesley Extension Sewer;
• Brairitree—Weymouth Interceptor;
• Frazninghaxn Extension Sewer; and
• Hingham Pump Station.
These projects and their associated grant reimbursements have been included as a
part of the t 4RA cash flow and cost projection outlook calculated for the STFP and
are therefore included in this analysis. The conservative assumption that no other
grant reimbursement will be included in this analysis has been made in ordering to
determine the largest financial impact on the individual users. However, it is
likely that other grants will become available sometime in the future.
The cash flow analysis presented in the STFP is used for this appendix. However, in
the STFP, one capital cost figure was developed and included in the analysis. For
this appendix, the cost of the outfall is varied to represent the three alternative
locations, thus changing the total cost figures of the cash flow analysis. The
dollar values for the cash flow analysis represent inflated dollars. Assumptions
made in the STFP to determine inflated dollars include:
• Construction costs will increase at a compounded rate of 6% per year.
• Operation and maintenance costs will increase at a compounded rate of 5%
per year.
• Projects on the State FY 1988 fundable list will get 85% combined federal
and state grant reimbursements (assuming that a portion of all projects are
ineligible for funding). Grant payments to the Authority will lag by six
months the date of the Authority’s expenditure.
Tables E.2.b, E.2.c, and E.2.d present the cash flow analysis, including expected
grant reimbursement as described above, for outfall alternative Site 2, Site i , and
Site 5, respectively. The duration of the construction period was based on dates
given in Table E.2.a and divided into 6 month increments.
E_1l
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TAStE E.2.b A STUUCTICU 0051 ANAlYSIS . INFLATED LAR CASIt FLOII 1. GRANT PROJECTION
SITE 2 WTFALL ALTENUATIVE.
VALUES tN $1000
DEER ITLANIT F FT FT •T F! FT FT FT FT F! FT FT FT FT FT FT FT FT
CO 1968 1989 1990 199 ! 1992 1993 94 1995 1996 199? 1998 1c49 2000 200! 2002 2003 2006 2905 TOtALS
E.rlylitePrep. $0 $8,912 19:447 10 10 •1 10 • 10 10 SO $0
5.1. SitePrep. I 10 10 10 13,070 $3,256 10 10 10 10 10 10 10 10 1.0 10 10 10 10 16,326
Pouer I Elec. FuclI. 10 $13,606 $28,861 $30,371 116,203 10 10 10 10 10 10 10 10 10 10 10 10 10 189.219
Nut Ne. .. , Twvtel, PS 10 10 117,497 137.0% 139,320 161,679 144,180 123,415 10 10 10 10 10 $0 10 10 10 10 1205,185
OJYFALL SITE 2 10 10 132,872 169.689 173.870 178,302 183,000 10 10 10 10 10 10 10 10 10 10 10 1337,733
Prim. Tre.t ZAPI 10 10 10 123,643 150,123 153,130 128,159 10 10 10 10 10 10 10 10 10 10 10 1155,055
Prim. Tre•t-ZAP2 10 10 10 133,672 171,385 137,836 10 10 10 10 10 10 10 10 10 10 10 10 1142,891
Prim. Trest18P3 10 10 10 10 125,8% 154,899 $58,193 $30,842 $0 $0 $0 $0 $0 10 10 $0 10 10 1169,830
lit. Pep. 2 10 10 10 14,8% $10,380 111,003 111,663 112,363 16,552 10 10 10 10 10 10 10 10 10 156,857
1.c . Tre.t 2A $0 10 10 10 10 10 10 162,584 1132,677 1140,638 1149,076 179,010 $0 10 10 $0 10 10 1363,985
Seccn. Trrat-21 10 10 10 10 10 10 50 10 $50,404 1106855 $113,267 1120,063 163,633 10 10 10 50 50 1454,222 -
Site Prep. 3 10 10 10 10 10 10 10 15,345 $11332 112,012 $12,733 $13,497 114.307 11,582 10 10 10 10 176,808
Engi’ srIfl9 Services 13. 180 $17,734 121,208 126,335 130,375 131,189 130,841 18,067 18,48! 18,439 18,966 16,913 12,535 1267 10 10 10 10 $206,470
Ol/LE Services $2,120 18,685 19,206 19,758 110,344 110,964 $11,622 $12,320 113,059 $13,842 $16,673 115,553 116,486 10 10 50 10 10 1148,632
U 5 .. . . ....s.... .. . .. flu...... ..... . ... u.n..... ..u.s.... • .flflu
TOTALS DI $5,300 $48,935 $119,071 $238,728 $331,152 $319,000 $267,658 1154,916 1222,505 $281 766 1298,695 1235,036 196,961 $7,829 $0 10 $0 10 12,627,572
GRANTS DI 10 13,788 17,803 14,015 10 10 10 10 10 10 10 10 10 10 10 10 10 10 $15,606
flu...... .n....fl fl..flfl. u S U Uu ufluu . u..nfl.. ...nuu.. a .u.. us... a flu...... uu 5 ....suU.. S
NET TOTAL DI $5,300 $45,167 $111,268 $234,713 $331,152 1319,000 1267,658 $154,916 1222,505 1281,706 1298,695 $235,036 $96,961 17,829 10 10 10 10 $2,611,966
NON.Dt PROJECTS
•;; ;: 5ft A i.. 10 50 $11,910 10 10 10 10 10 10 10 10 $0 10 10 10 10 10 10 111,910
Ne.idos t . . 1995 AIE-Oth 10 10 50 $11,067 $11,709 $0 $0 10 10 10 10 10 10 10 $0 10 10 10 122,756
Resló.ssIs . 1995 Ccnetru. 10 10 10 10 $33,456 170,926 175,182 $39,846 10 10 10 50 10 10 10 10 10 10 $219,410
IesI 1s 2000 AlE •Oth 10 10 10 10 10 10 18,72! 19,244 19,948 10 10 10 10 10 10 10 10 10 127,933
1e si jai s . 2000 Coi tru. 10 10 10 10 10 10 10 10 156,316 $119,390 1126,553 167,073 10 10 $0 10 10 $0 $569,332
lnterc. $ PS Grlts 15,056 135,023 131,086 $32,951 $0 $0 1.0 10 10 10 10 10 10 10 10 10 10 10 $106,116
Other tnt. I PS Pb. I 115,995 $9,918 $40 163 10 0 $0 10 10 10 10 10 10 10 10 10 10 10 126,096
Other tnt. & PS . Pb. 2 10 11,809 $1,215 11,288 10 10 $0 50 1.0 $0 10 1!) 10 10 $0 10 10 10 14,312
Other tnt. $ PS . Pb. 3 10 10 114,888 115,761 10 10 10 10 10 10 10 10 10 10 10 $0 10 10 130.669
Other tnt. I PS Pb. 6 10 10 10 10 $16,126 117,093 $18,119 $19,206 SO $0 10 10 10 10 10 10 10 10 110,544
Ac Snin.lOther 10 10 111,865 $18,937 $20,073 121,278 122.554 123,908 125,342 126,863 128,674 $30,183 $31,994 $33,914 135,968 $30,105 $60,392 $42,815 $458,665
i Shorel i st. Piers $2,014 $19,337 $18,000 10 10 50 10 10 10 10 10 10 10 10 10 10 10 10 139,35!
Trsnsp. Costs $0 10 18,915 122,568 $20,723 $20,535 $25,112 121,514 122,354 122,520 $18,259 $19,072 10 10 10 10 10 10 1201,570
Trenep. Site Cost 150,000 $10,449 10 10 so so so $0 10 10 10 $0 $0 10 10 50 10 10 160,449
. ..u.. . ... ......... ....... .. ..... .. ......... u. n. u.... ...n. ..u.. ........U Ufl.flS flu a
TOTALS uON.Dt 173,065 176,596 $105,937 $102,635 $102,087 $129,832 $169,688 $113,718 1113.980 1168,773 1173,286 $116,328 131,994 133,914 135,948 $30,105 $40,392 142,815 $1,647,095
GRANTS . 508.01 13,005 $26,108 143,964 134,865 114,006 10 10 10 10 10 10 10 10 10 10 10 10 10 $121,946
.. ......... .. .... n... .....uu .... .uSfl flfl•flfl •u S• Su• fl.S...uu a
NET TOTAL . NON DI $70,060 150,688 159,973 167,770 $88,083 1129,632 $149688 $113,718 $113,960 1168,773 $173,286 1116,328 $31,994 $33,916 135,948 $30,105 140.392 $42,815 11,523,167
GRAND TOTAL 00N 5T 1’JCTION $70,365 1125,531 $223,008 $341,363 1433,239 1446,032 1417,346 1268,636 1336,485 1.450.559 $471,981 $351,366 $128,955 $41,743 $35,948 $38,105 $40,392 182,815 $4,274,665
GRAND TOTAL GRANTS $3,005 $29,896 $51,767 130,880 116,006 10 10 $0 10 10 10 10 10 10 10 , $137552
GRANT TOTAL . NET $75,360 $95,635 $171,241 $302,483 1419,235 1440,832 $417,366 1268634 1336485 $471,981 $351,364 $128,955 $41,743 $35,948 136,185 160,392 142,015 $4,137,113
Source: Ac ,eted Eros NTA, STFP VII, 1987.
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TABLE E.2.c A aINSTIUCTI05 00ST MALTSIS - INFLATCO DOLLAR CASH FLmI I GBANT PROJECTI05
SITE 6 7JtFALL ALTERNATIVE,
VALt S IN 11000
DEER ISLAND FT FT FT FT FT FT IT Ff F’ fT fT FT FT F! FT FT FT FT
CONTRACTS 1958 1989 IWO 1991 1992 1993 1994 1995 1996 1617 1998 1999 2000 2001 2002 20)3 O06 2005 TOTALS
E.rly Site Prep. 10 $8,912 19,467 10 50 SO 10 10 10 30 10 10 10 10 30 10 SO 10 818.559
Bit. Site Prep. 1 50 10 10 13,070 83,256 10 10 80 10 10 10 10 10 10 10 10 10 $0 16 ,3M
P r £ (lec. F.cil. SO $13,606 120,861 $30,571 116.203 SO 1.0 30 10 50 10 10 50 50 10 10 30 50 $89,219
Nut Ne. .., Iwv,eI, PS 50 10 $17,697 537,096 839.320 141,679 144,180 123.415 10 10 SO 10 30 10 10 10 10 30 1203,185
JTFALL SITE 4 10 10 $42,116 189,292 $94,650 5100,329 $106,349 $112,730 30 50 50 10 10 10 80 10 10 10 1545,664
Pr,.. Treat ZAPI 10 10 50 123,645 850.123 153,130 128,159 10 10 10 SO 30 $0 10 50 10 *0 10 $155,055
Pri.. Ire.t-ZAP2 10 50 10 133,672 $7I 38S 137,034 1.0 $0 1.0 10 50 10 10 10 30 10 10 50 1142,591
PrI.. Treat-lOPS 10 10 50 10 125.8% 156,099 $50,193 $30,842 10 50 10 10 50 10 10 $0 30 10 1169,830
Site Prep. 2 $0 10 10 $4,896 $10,380 $11,003 $11,663 $12,363 16.552 30 10 50 $0 50 50 50 10 10 356,857
Secon. Treet-2* 50 10 10 30 50 SO 10 162,584 $132,677 $140 638 $149,016 $19,010 10 10 10 SO $0 SO $565,985
Secon. Treet-29 $0 10 $0 80 50 10 10 10 $50,404 $106,855 $113,267 $120,063 163.633 30 1.0 30 10 10 $454,2?2
Site Prep. 3 10 10 10 10 10 $0 SO 55,345 $11,332 $12,012 S12,733 $13,497 $14,307 $7,582 10 10 30 10 876,808
Enqineering Service. $3,180 SI,,?)’. 821,208 526,335 130,375 $31,189 $30,041 18,047 18,48) $8,439 18,946 16.913 12,535 1267 10 10 50 10 1204,670
CHILE Services $2,120 $8,685 19,206 39,750 $10,346 $10,964 $11,622 $12,320 313,059 $13,542 116,673 115.555 $16,486 SO $0 $0 10 30 1168,632
TOTALS DI $5,300 $48,935 $128,313 3258,331 $351,932 $341,027 $291,007 5267,646 $222,505 5201,786 5298,695 $235,036 396,961 $7,829 $0 10 50 10 12,833,303
GRANTS Dl $0 $3,788 $7,803 14,015 $0 30 10 10 50 30 50 10 30 10 10 $0 10 10 $15,606
u.s_n.. n S S a Sn ——
NET TOTAl. DI $5,300 145,147 1120,510 $254,316 $351,932 $341,027 1291,007 1267,646 1222,505 1281.786 $298,695 3235,036 196,961 $7,829 $0 80 10 $0 S2 5I9,697
05•Li PROJECTS
l :SI;i Acipile. 10 $0 $11,910 10 50 50 10 10 10 $0 10 10 80 30 50 10 10 10 $11,910
RrsI ate . 1995 F./(-Oth 10 10 10 111.047 $11,709 10 50 10 10 50 50 10 10 10 10 10 10 10 122,756
111 Aeui i .Iu - 1995 Conetru. 30 10 10 80 133,456 170,926 $75,182 159,046 10 50 50 10 10 50 10 10 50 10 $219,610
lnIôjuls - 2000 A/E 0th 10 30 10 10 10 10 18,721 19,264 19,968 50 10 10 10 10 5.0 10 10 30 127,933
0 ’ ResiôJstu . 2000 C tru. 10 10 10 10 10 10 10 30 $56,316 $119,390 $126,553 867,073 10 10 10 50 30 10 1369,332
Interc. I 95 Grunt. 15,056 $55,025 131,006 $32,951 10 10 10 50 10 10 10 50 10 10 10 10 10 10 $104,116
Other hit. & PS Pb. I $15,995 19,978 160 163 10 10 10 10 10 10 10 10 50 10 10 10 10 10 126.096
Other mt. & PS - Pb. 2 10 $1,809 11,2)5 $1,208 10 10 10 10 10 10 10 50 50 10 $0 10 10 30 $4,312
Other tnt. I PS - Pb. 5 10 10 $14,558 115,78) $0 30 10 10 10 10 10 $0 10 10 10 80 50 10 $30,669
Other m l. I P3 Pb. 4 10 10 10 10 $16,126 $17,093 $10,119 $19,206 30 30 10 10 10 10 10 10 10 10 370,544
Ad. in.lOther 10 50 $17,865 318.937 820,073 $21,278 $22,554 123,908 125,342 $26,063 $28,476 130.183 131,996 $33,916 135,948 138,105 140,392 $42,815 1458,645
i Shore/mi t.I. Piers $2,014 $19,337 $10,000 10 10 10 30 10 10 10 10 50 10 10 30 50 10 10 139,351
Trunep. Cost. 10 $0 $8,915 $22568 $20,723 120,535 125,112 $21,516 $22,356 $22,520 $18,259 $I9 Ofl 10 10 10 10 10 10 1201,570
Tr.nsp. Site Cost $50,000 $10,449 50 10 10 50 10 10 10 50 10 30 10 10 10 10 80 10 160,449
5Ssu•• 5 • s 5 _ s5 n n
TOTALS - NON-DI $73065 $76,596 $103,937 $102,635 1102,087 $129,832 $149,688 $113,710 $113,980 $168773 $173,286 $116,320 $31,994 $33,916 $35,948 $38,105 140,19? 362.015 $1,647,093
GRANTS . NON DI $3,005 126,108 143,964 534,865 $14,004 10 50 30 $0 10 $0 50 30 10 $0 10 10 10 $121,946
U Sen Sn. s 5 n.s.a n
NIT TOTAL . NON D I 170,030 150,488 159,975 167,770 188,083 1129,032 $149,685 $113,718 $113,980 $168,773 $173,286 $116,328 $31,994 $33,916 $35,968 138,105 140,392 $42,815 $1,525,147
GRAND TOTAL STRt TION $78,365 $125331 1232.250 8368,966 $454,019 5478,859 1440,695 $351,366 5336,483 3450,559 1471,901 5351,364 $125,955 161,743 855.940 $38105 140,392 342,015 34,482,396
GRAND TOTAL . GRANTS 13,005 329,5% $31,767 $38,580 $16,004 10 $0 10 10 50 10 30 10 50 10 10 10 10 1157.552
63*89 TOTAL NET $75,380 $95,633 $180,483 1322,086 $440,015 $470,859 3440,895 1381,364 1536,485 1450,559 $471,981 $351,366 1128,955 141,743 335,948 $38,105 $40,392 142.015 34,344,064
Source: Adapted Frau A, STFP VI !, 1987.
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yULE E.2.d. A GRNSTUUCTION 005T AUALTSI$ - INFLATED DINLAN CR111 FLmI & GRANT PROJECTIGR
SITE S GJTFALL ALTERNATIVE.
VAL( 5 IN 11000
DEER ist*im FT FT FT FT fl FT 7’ FT FT VT FT ‘V FT FT FT FT FT F’
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1996 1991 2000 2001 2002 2003 2006 2005 TOtALS
E.rty$It.Pr ep. $0 16,912 19,447 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 118.359
$ 51. Sits Prep. 1 10 10 $0 13070 13.256 10 10 10 10 10 10 10 10 10 10 10 10 10 16.526
Poser I Etec. Facil. 10 113.604 128,841 130.571 116203 $0 10 10 10 10 10 10 10 10 10 $0 10 10 189,219
Nut N..& ., Twvist, PS $0 $0 $17,497 137.094 159,320 541,679 $44,110 123,4*5 10 10 10 10 10 10 10 10 10 10 1203.185
GITFALL SITE 5 10 10 146,650 198,473 1104W 1110445 $117,283 $124,320 $65 890 10 10 10 10 10 10 10 10 10 1667,443
Pri.. Tr..t-ZJPI $0 $0 10 123,643 $50,123 $53,130 $28,159 50 10 10 10 10 10 10 10 10 10 10 $155,055
Pri.. Tre.t-ZRPZ 10 10 10 133672 171,385 $37,834 10 $0 10 10 10 10 10 10 10 $0 10 10 $167,891
Pri.. Tr..t-Z1P3 10 10 10 10 125,9% 154999 $58,193 130.842 10 10 10 10 10 $0 $0 10 10 10 $169,830
Site Prep. 2 $0 10 10 $4,896 110,380 $11,003 111663 112,563 16,552 10 $0 10 10 1.0 10 $0 $0 10 156857
Iscun. Trees-ZR 10 10 10 10 10 10 10 162,584 $132,677 $140,638 $149,076 179,0*0 10 10 10 10 10 10 1663,985
leccn. Trest-ZO 10 10 10 10 10 10 10 10 150,404 $106,855 1113,267 1120,063 163,633 10 10 $0 10 10 1454,222
lit. Prep. 3 $0 10 1.0 10 10 10 SO 15,3.5 111,332 $12,012 112,733 113,497 116,307 $7,582 10 $0 10 $0 $76,908
Engine.rIn Services 05,180 117,734 121208 126,335 130,325 $3 1,t89 $30,841 $8,047 $8,481 $8,439 18,946 16,913 $2,535 $247 10 10 10 10 $204,470
DVLE Services $2,120 $8,685 19,206 19,258 $10,344 $10,964 $11622 $12,320 $15,059 $13,842 $14,615 115553 $16,486 10 10 10 10 10 $148,632
f in .....n ass. U 5 s S a fl n an fle as as fl.. .s _____ e• ..S flUS CS ..n.nn...
TOTALS • DI 15,300 $48,935 1132,849 1267,512 $381,664 $351,343 $301,941 $279,236 $288,395 $281,706 $298,695 1235,036 196,961 17,829 50 10 10 10 12,957.282
GRANTS-b! $0 $3,188 17,805 14,015 10 10 10 10 10 10 10 10 10 10 10 10 10 10 $15,606
n..nn. .5. flsflflfl U.S...... U SS SUa• .flun... a... flflS .Ufl flfl..fl. as fins.. _ . __ __ . . ass...... .nS..fiU
OTT TOTAL • DI $5,300 145,147 $124,816 $263,497 $361,664 $351,343 $301,941 $279,736 $288395 $281,186 $298,695 $235,056 196,961 17,829 10 10 10 10 $2,941,676
88-DI PROJECTS
Iesl ais-1i;.AcquI.. 10 $0 111,980 10 10 $0 $0 $0 $0 50 10 10 10 10 10 10 10 10 111.910
lesI aIu - 1995 A/E-Oth 10 10 10 $11,047 111,709 10 $0 10 10 10 10 10 10 10 $0 10 10 10 122,256
Resi aIs 1995 C tru. $0 $0 10 10 133,4% 170,926 125,182 $39846 10 $0 10 50 50 $0 $0 10 10 10 $219,410
.4 Reui j.I.-2000AFE-0th $0 10 10 10 10 10 58,721 19,244 19,968 10 $0 10 10 10 10 10 10 10 $27,933
Re .i&mI . 2000 C tru. 10 10 10 10 10 10 10 10 $56,316 $119,390 $126,553 167,073 10 10 10 10 10 10 $369352
Interc. & 91 - Grunt. $5,856 $35,023 531,086 132,95* 10 10 10 10 10 10 10 $0 10 10 50 10 10 10 1106,116
Other mt. $ PS Pb. 1 115,995 19.918 160 163 10 $0 10 10 10 10 10 10 10 10 10 10 10 10 126,096
Other mt. I PS - Pb. 7 10 $1,909 11215 11,286 10 10 10 10 10 10 10 10 10 10 10 10 10 10 16,5*2
Other mt. $ PS Pb. 3 $0 $0 $14688 $15,781 10 10 10 10 10 10 10 10 10 10 10 10 10 10 130.669
Other tnt. $ PS Pb. 4 10 10 10 10 116,126 117,093 118.119 $19,206 10 10 10 50 $0 10 10 10 10 50 170,544
Ad.InjOth.r $0 $0 $17,865 $18,937 120,073 121,218 122,554 $23,908 $25,342 $26,863 128,474 130,183 131,9% $33,916 133,948 908,105 160,392 142,815 $458,645
G ShoreIG 1.1. Pier. $2,014 $19,337 118,000 10 10 10 10 10 10 Ii) 10 50 10 10 10 10 10 50 $59,351
Tranep. Costs 10 10 $8,913 $22,566 $20,723 120,535 125,112 121,514 $22,354 $22,520 $18,259 $19,072 10 10 10 10 10 1.0 $201,570
Trunsp. Site Cost $50,000 $10,449 10 10 10 10 10 10 10 10 $0 10 10 10 10 10 10 10 160.449
5 flUnflfl SS• flu... . .. USUSUn SUSSS aSSsUfl S • •5 n f l .... an...... flaSSsSSS Sn...... 55U 5UsU ..fl.a... UU 5flfl flS U S
TOTALS - -bt 173,045 176,5% $103,937 1*02,635 $102,087 $129,632 $169,688 $113,718 $113,980 $168,773 $173,266 $116,326 $31,994 $33,914 $35,941 138,105 140,392 142,815 11,647,093
GRANTS . -Dt 13005 126,108 143,964 134,865 $14,004 10 10 10 10 10 10 10 10 10 10 10 10 10 $121,946
Sn. flSflSflU fl fl •flflflfl Ufl5SStU fl n anus... U.... ...fl. aflUen U 5 5 .sUsU ____ fl UflSSU• afl
NET TOTAL - 901-01 170,060 150,488 159,973 167,770 188,083 $129,832 $149,688 1113,718 1113,980 1168,173 $173,286 1116,328 $31,994 $33,916 $35,948 $38,105 160,392 142,815 $1,525,147
88*88 TOTAL . STmETI90 118,365 1125531 1256,566 1370,147 $113,751 $181,175 1651,629 $392,954 1102,325 $150,559 1671,981 1551,384 $128,955 $41,743 135,948 136,105 140.392 142,811 14,604,325
88*80 TOTAL - GRANTS $3,005 $29,896 $51,767 $38,810 $14,004 10 10 10 10 10 10 10 10 10 10 10 50 50 $137,552
GRANT TOTAL - NET $75,310 $95,635 $184,819 $331,267 1449,767 $481,175 $451,629 5392954 1402.325 1450,559 $671,981 1351,364 1128,955 $41,743 $35941 $38,105 140,392 142,815 14,466,823
Source: Adupted fros 11A, STFP VII, 196?.
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E.2.2 OPERATING EXPENDITURES
Operating costs were developed in the STFP and included direct costs of the sewerage
division, an allocation for MWRA administrative and support expenses, expenses
associated with operation and maintenance of the treatment plant, transportation and
residuals management aspects of the new treatment facilities. Operating costs were
determined on an annual basis from 1988 to 2005.
The costs, if any, allocated to operating and maintaining the outfall were not
presented separately in the operating expenditure analysis completed for the
Facilities Plan. For each outfall alternative, wastewater is discharged from the
treatment plant, specifically the chlorine contact chambers, and is conveyed by
gravity through the outfall. No operation and maintenance of pumps is required.
Also, little or no maintenance over the life of the outfall pipe is needed.
Therefore, as total cost impacts are evaluated for each outfall alternative site, it
was assumed there is no impact on the operating expenditures. The operating
expenditures will remain constant for each outfall site evaluated.
E.2.3 REVENUE REQUIREMENTS
For this appendix, it is assumed that 100 percent of MWRA’s net cost of financing
the new treatment plant facilities will be passed through to the communities the
MWRA services. To determine the amount of funds to be raised, several different
economic variables were considered in the STFP (MWRA, STFP VII, 1987). Assumptions
in the STFP made when determining the revenue requirement included:
• Bonds will be sold yearly, in amounts sufficient to pay the capital cash
flow and debt reserve requirements net of grants-in-aid receipts.
• Bond proceeds to the Authority would represent 85% of the face value of the
bonds. This means that items such as underwriter’s discount, bond
insurance, capitalized debt service, reserve-deposits, coverage, issuance
costs, etc. would represent 15% of the face value of the bonds. The
remaining 85% would be available to the Authority to finance construction
projects.
• Authority revenue bonds would carry an average annual interest rate of 9%
and would mature in 30 years. The bonds would be structured for level
annual debt service payments.
E-8
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• The first Authority revenue bonds will be issued in 1990.
• All existing and future short-term borrowings will be rolled over into a
long-term (30 year) bond issue in 1990. The amount of the rollover related
to wastewater projects is estimated to be $330 million.
• Funds and reserves held by the Authority would earn interest at the rate of
9 per year. These funds and reserves were assumed to include:
- An O&M (Operation and Maintenance) reserve equal to 20 of the annual
O&M expense
— An RRR (Renewal. Replacement and Repair) reserve that will be built up
in equal annual increments from $10 million to $50 million by 1995
— An Insurance reserve that will be built up in equal increments from
$2.5 million to $20 million by 1995
— A debt service reserve fund equal to the maximum annual principal and
interest payments due on any outstanding MWRA revenue bonds.
Based on these assumptions, revenue requirements were developed for the years 1990
to 2005. Table E.2.e presents comparisons of the revenue requirement for each
outfall alternative. The revenue requirement is the amount to be charged to the
member communities.
E.3 IMPACT ON MEMBER COMMUNITIES
The revenue requirements presented in the preceeding section will be the total
amount that must be recovered from the i43 communities that the MWRA services. The
communities are charged a lump sum percentage of the total revenue requirements
based on a community’s population or population equivalents.
The actual percentage of the total MWRA revenue costs assessed to each community was
not clearly defined in the STFP. Assumptions were made in order to estimate the
annual MWRA assessment to each community so that the financial impact on the
individual sewer users could be calculated. The cost and construction duration of
the three alternative outfall locations will cause the annual MWRA revenue
requirements to vary. It is assumed that the portion of the revenue requirements
consisting of the MWRA annual operating costs will remain constant since little or
no operating costs are required to maintain any of the outfall alternatives. The
E-9
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TARE (.2.. WA1I50N OF CAPITAL USA PLW AIM ANIUJAL REVENUE UEOUIIEIENTS FOT EACN
(IJIFALL ALTERNATIVE, INFLATED DOLLARS,
VALUES IN $1000
F I SCAI TEAR
1988 1989 1990 1991 1992 1993 19% 1995 1996 1991 1995 1999 2099 2001 2002 2003 2004 2005 TOTALS
SITE 2
NET CAPITAL US! FL1 $75340 $95,635 $171,241 $302,453 $419,235 $465,532 3417,346 $265,634 $336,455 $450,559 $471,981 $351,364 $128,955 14 1,743 535,965 $35,105 540,392 $42,515 $4,137,113
0 $ N OFERATING 00575 & 544,460 $67,880 $95,366 $121,131 $122,326 $125,032 $134,915 $122,063 $122,723 $129,929 $134,906 $I61,95 *209,695 $213,017 3223,665 $234,851 $246,594 $258,924 $2,771,457
RESERVE DEPOSITS
MMML REVEINW RE(IIIREI€NTS •‘ •. 5139,322 $187635 $232,454 $254,912 $335,244 $271,963 $366.30? 5479,956 5533,549 5596,563 $655,789 5663,096 $677,194 $688,106 $703,845 $720,419 57.536.335
SITE 4
557 CAPITAL CASN FLW $75,360 $95,635 3180.453 $322,086 1440,015 3470,859 $440,695 $351,364 $336,485 $450,559 $471,951 $351,364 $128,955 $41,763 $35,965 $38,105 $40,392 $42,815 $6,344,844
0 $ N OFERATINO 0057$ & $44,460 $67,880 $95,386 $121,131 $122,326 $128,032 $134,915 $122,063 $122,723 $129,929 $134,906 $161,954 $209,698 $213,017 $223,668 $234,851 $246,594 $258,924 $2,771,457
RESERVE DEPOSITS
MRML REVEfl REmI IRENENTS ‘. $145,564 $201,238 $253,234 5306,939 $358,593 $384,693 $366,307 $470,956 $533,569 $596,543 $655,789 $663,094 $677,194 5688,106 $703,845 $720,419 $7,744,066
SIlt S
NET CAPITAL CASN FLW $75,360 $95,635 $154,819 $331,267 $449,747 $481,175 $451,629 $392,954 $402,375 $450,S59 $471,981 $351,364 $128,955 $41,763 $35,955 $38,105 $40,392 $42,815 $4,466,823
01 N OFERATINC OSSTS & $44,460 $67,880 $96,386 $121,131 $122,326 $128,032 $134,915 $122,063 $122,723 $129,929 $134,906 $161,956 $209,698 $213,017 $223,668 $234,851 $246,594 $258,924 $2,771,437
RESERVE DEPOSITS
ARIRML REVEU RE(IIIREICNTS .. .. $152,900 $216,419 $262,966 $317,25S $369,S27 $396,253 $432,197 $470,956 $533,549 $595,543 $655,709 $663,094 $677,196 $688,106 $703,845 $720,419 $7,866,045
Source: AdapTS I r MA, STEP VII, 1987.
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MWRA capital cost portion of the revenue requirement would vary for each outfall
alternative. For these reasons, when determining the MWRA capital cost assessment
for each community, it was necessary to calculate a percent annual allocation of
MWRA capital costs based on total MWRA capital cost figures and the capital cost
previously allocated to the communities in the Facilities Plan. This annual percent
figure varied yearly for each community. This methodology was used for both Boston
and Needhaxn.
It is the responsibility of’ the communities to implement the sewer rate changes to
the individual users. Each community has established methods of’ calculating sewer
rates, which include recovering the MWRA assessment as well as local capital and
operating expenses of’ the community sewer system. The methods of’ recovering the
costs vary from incorporating all charges into a water and sewer bill to complete or
almost complete recovery through property taxes (MWRA, STFP VII, 1987).
Impacts on sewer use charges for two communities, Boston and Needham, were analyzed
during the STFP. Boston was selected to represent communities which completely
recover water, sewer, and drainage expenses through water and sewer rates. Needharn
Was selected to represent communities that recover costs based on a combination of
sewer rates and property taxes. These same communities will be analyzed in this
appendix to represent financial impacts on member communities.
An analysis of local expenses incurred by the two communities had to be developed in
order to determine the total impact on sewer users, of which the MWRA costs are a
part. An analysis of the future costs and needs of the communities was undertaken
during the STFP. Assumptions made in order to complete the financial impact
analysis for the two communities include (MWRA, STFP VII, 1987):
• Local operating costs will be affected by inflation in the same manner as
the KWRA’S operating costs and would thus increase by the same inflation
factor of a compounded rate of 5% per year.
• There would be no change (unless otherwise identified) in the communities
current cost recovery philosophies and/or practices. For example, BWSC
would maintain its current 10—step inclining block rate structure and
increase all rates by the same percentage to recover increasing costs. It
is also assumed that the costs recovered through property taxes would
continue to be recovered through this mechanism throughout the period
analyzed.
E—1 1
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• There would be no significant change in a community’s customer base--that
is, there would be no increase in water/wastewater customers over which
increased costs could be spread. Water use was assumed to remain stable
throughout the period.
• The total valuation of property in a town would increase annually by 8% to
account for inflation and limited growth.
• The valuation of a typical property would increase annually by 5%.
For Boston, the impact of cost when the outfall site is varied is considered for
three types of sewer users. The sewer rates are calculated for residential, small
commercial and large commercial consumers. For Needhaxn, impacts on a residential
and large volume consumer, such as an apartment complex, commercial user, or
institution, are evaluated. A discussion for each community follows.
E.3.1 BOSTON
In the city of’ Boston, a financially independent agency, the Boston Water and Sewer
Commission (BWSC), is responsible for operating the water, sewer and drainage
services, as well as recovering all costs for their expenses. All costs are
recovered through water and sewer rates. For this analysis, only the impacts on the
sewer portion of a user’s bill is considered.
Estimates of BWSC’s local capital and operating expenses to the year 2005 were
developed during the Facilities Plan. The same estimates are used for the financial
impact analyses for the three outfall alternatives in this appendix.
The BWSC currently uses a ten step inclining block rate structure for billing
purposes. The financial impacts on this rate structure were estimated in order to
calculate estimated sewer rates for various users.
Three categories of users, residential, commercial, and large commercial, are
evaluated. The single-family residential user Is estimated to consume 10,000 cu.
ft./yr. of’ water, the commercial user consumes 500,000 cu.ft./yr., and the large
commercial user consumes 5,000,000 cu. ft./yr.
E-12
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Tables E.1 through E.6 in the back of this appendix present the expense projections
and sewer use charges for Boston. The BWSC expense projections for the Site 2
outfall alternative is presented on Table E.1. The estimates for the ten block rate
schedule for Site 2 is presented on Table E.2. Annual sewer use charge estimates
for a 10,000 cu. ft./yr. residential user, a 500,000 cu. ft./yr. commercial user,
and a 5,000,000 cu. ft./yr. commercial user are also presented on Table E.2. For
the Site li outfall alternative, Table E.3 presents the BWSC projected expenses and
Table presents the impacts on the rate structure and the three types of sewer
users. For Site 5, Table E.5 presents the BWSC projected expenses and Table E.6
presents the impacts on the rate structure and the three types of users.
A summary of sewer use charges for the year 1990 to the year 1997, preáenting a
comparison of the sewer use charges for each outfall alternative, is shown on Table
E.3.a for the three categories of sewer users. In order to evaluate the financial
impact on the three alternative outfall locations, the same bond amounts having the
same duration was assumed for each outfall site, with all construction scheduled to
be completed by FY 1996. Therefore, no incremental change in sewer rates occurs for
the year 1997 through the year 2005. The sewer use charge remains the same for
these years.
E.3.2 NEEDHAM
Needham recovers its sewer expenses through a combination of sewer use charges and
property tax assessments. A recent policy was adopted regarding wastewater expense
recovery whereby the last Metropolitan District Commission (MDC) assessment charge
to the town prior to the creation of the MWRA, which was $297,575, plus all local
wastewater-related expenses will be recovered through a property tax assessment.
All MWRA assessments in excess of the last MDC assessment will be recovered through
a local sewer use charge system. Using this methodology, the majority of sewer
charges attributable to the new MWRA wastewater treatment facilities will be
recovered through the sewer rate charge. For the purposes of determining the
impacts of the three outfall alternatives, the property tax assessment would remain
constant for each alternative. Only the sewer rate portion of the user charge would
vary.
E- 13
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TABLE E.3.a SUMMARY OF ANNUAL SEWER USE CHARGES FOR THE OUTFALL ALTERNATIVES, BOSTON
YEAR
1990 1991 1992 1993 199 1 1(1) 1995(1) 1996(1) 1997
Residential
(10,000 Cu ft/yr)
Site 2 $180 $225 $260 $301 $3110 $313 $370 $1146
Site II 182 229 265 307 3118 370 370 11116
Site 5 183 230 267 310 352 375 1106 4116
Commercial
(500,000 cu ft/yr)
Site 2 $11,716 $111,656 $16,980 $19,637 $22,146 $20,410 $211,112 $29,105
Site 14 11,849 111,906 17,275 20,035 22,711 24,109 211,112 29,105
Site 5 11,911 15,023 17,1113 20,222 22,975 24,489 26,515 29,105
Large Commercial
(5,000,000 cu ft/yr)
Site 2 $98,767 $123,547 $143,138 $165,533 $186,688 $172,053 $203,261 $245,348
Site 11 99,882 125,6511 1115,623 168,896 191,11119 203,3211 203,261 245,348
Site 5 100,1105 126,6141 1146,786 170,1171 193,678 206,1140 223,519 245,3118
1. Site 2 construction completed in 1994, resulting in a decrease in user charges for 1995. Site 14 construction
completed in 1995, resulting in approximately equal charges for 1995 and 1996. Site 5 construction completed
in 1996.
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During the STFP, estimates for local operating expenses for the sewer system were
developed for the years 1987 to 2005 (MWRA, STEP VII, 1987). These same expense
projections were used as the base for the calculation of user charges in this
appendix.
Sewer charges for two categories of users, residential and large volume, are
estimated for Needhaxn. The breakdown for the sewer rate charge and property tax is
presented. The financial impact for each of the three selected outfall alternatives
is presented.
Tables E.7 through E.12 in the back of this appendix present the expense projections
and sewer rate and property tax expenses for Needham. The projected wa tewater-
related expenses for Needhazn for the Site 2 outfall alternative including a sewer
rate and property tax expense breakdown is presented on Table E.7. The projected
sewer charges for the average single family home residential user and for a large
volume user is presented on Table E.8 for Site 2. Table E.9 presents expense
projections and Table E.10 presents user charge projections for the Site 14 outfall
alternative. Table E.11 presents expense projections and Table E.12 presents user
charge projections for Site 5 outfall alternative.
As stated for Boston, all three outfall alternatives are scheduled to be constructed
by FY 1996. Also, the same bond amounts with the same durations is assumed for each
alternative so sewer use charges from 1997 to 2005 will remain constant. A summary
of the sewer charges for a residential (10,000 cu. ft./yr.) and large volume (30,000
cu. ft./yr.) user are presented on Table E.3.b.
E.4 COMPARISON WITH NATIONAL AVERAGE
Each t4WRA member community develops its own methodology when billing individual
sewer users. Typical methodologies range from one hundred percent recovery through
sewer rates to a combination of sewer rates and property tax, to full recovery
through property taxes. Because of the various recovery mechanisms used,
comparisons of user charges between communities are not totally valid.
E-15
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TABLE E.3.b SUPOIARY OF ANNUAL SEWER CHARGES FOR THE OUTFALL ALTERNATIVES, NEEDHAII
YEAR
1990
1991
1992
1993
19911(1)
1995(1)
1996(1)
1997
Residential
(10,000 Cu
ft/yr)
Site 2
$222
$279
$326
$379
$‘ 128
$390
$1166
$568
Site 11
225
2811
332
387
11111
1169
1166
568
SIte 5
226
287
335
391
1146
l77
517
568
Large User
(30,000 cu
ft/yr)
Site 2
$1183
$6’ 19
$787
$9113
$1,089
$972
$1,196
$1,498
Site 11
1192
665
805
968
1,125
1,208
1,196
1,498
Site 5
1 196
672
8111
980
1,142
1,232
1,349
1,498
t ’I
0 ’
Site 2 construction completed 19911, resulting In a decrease in user charges for 1995. Site 11 construction completed
1995, resulting in a slight decrease In user charges In 1996. Site 5 construction completed 1996.
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When comparing user charges nationwide, the same discrepancies exist. Due to the
various methodologies developed to recover charges, it is unfair to compare user
charges in one city with that of another.
To get some idea of how MWRA expenses compare with other cities, estimates made on a
grosser scale are compared. A nationwide financial survey was recently completed by
the Association of Metropolitan Sewerage Agencies (AMSA, 1987). A comparison of the
treatment cost per million gallons per day (mgd) was made.
The MWRA currently serves a population of 1.9 million. Agencies serving a
population greater than one million are included in this comparison. Twenty-one
agencies having a population greater than one million responded to the f.inancial
survey and are included in this comparison. The treatment cost per mgd ranged from
$2314 to 81,0314 in 1985 dollars with a mean of $1420. These rates were compared to
1990 MWRA revenue requirements. Using a 5 percent per year inflation factor, the
1990 treatment cost per mgd for the 21 agencies ranges from $299 to $1320 with a
mean of $536. The 1990 MWRA treatment cost per mgd, using a flow rate of 380 mgd,
is $367 for Site 2, $391 for Site 14, and $1402 for Site 5.
The MWRA treatment cost per mgd values are in the lower to average range in 1990.
However, after 1990, MWRA expenses will increase as the wastewater treatment
facilities are constructed. It is unknown what future expenditures will be incurred
by the national agencies but it is likely the MWRA cost per rngd will escalate to the
higher end of the current national average.
E.5 IMPACTS ON USERS
The financial commitment required to clean up Boston Harbor will impact every user
of the MWRA’s sewer system. Charges related to sewer use will increase from $100 in
1987 to $663 in 2005 for a single—family home residential user in Boston, a
660 percent increase. In Needham, the single-family home residential user sewer
costs will rise from $138 in 1987 to $815 in 2005, a 590 percent increase.
Estimates for the year 2005 are in inflated dollars. Users of the MWRA system in
each of the 143 member communities will have a similar increase in their sewer use
charge.
E- 17
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A comparison between the three selected alternative outfall locations, Site 2,
Site I, and Site 5, was made to determine the financial impacts of chosing one
alternative rather than another. Depending upon the alternative chosen, the
financial impacts of the outfall would effect the MWRA’s cash flow between 1990 and
1996. From 1990 to 199 4, the incremental difference in the sewer use charges
between the three outfall locations ranges from 1.6 percent to 3.6 percent.
The completion of an outfall does impact the sewer use charges for an individual
user as shown on Tables E.3.a and E.3.b. In 1995, a 12 to 21 percent difference
between alternatives exists and in 1996, a 9 to 11 percent difference exists.
However, in 1997 when each of the potential outfalls would be completed, the sewer
use charge for each outfall alternative becomes equal. The two-year period when
Site Z and Site 5 are continuing to be constructed does cause an increase in sewer
charges. However, the duration over which the increase occurs and the financial
increase to the sewer use charge does not warrant selecting one alternative outfall
location rather than another.
The financial impact on the individual sewer user will be significant, no matter
which alternative outfall site is selected. The two communities analyzed, Boston
and Needham, illustrated the impacts on typical users. The other 141 member
communities can also expect significant increases in their IIWRA assessment, as well
as increases in the sewer use charges to the individual users in their community.
E-18
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REFERENCES
Association of Metropolitan Sewerage Agencies, 1987. Municipal Wastewater Treatment
Facility Financial Survey. Washington, D.C.
MWRA, STFP VII, 1987. Secondary Treatment Facilities Plan, Volume VII,
Institutional Considerations. Massachusetts Water Resources Authority.
Charlestown, MA.
E- 19
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TABLES E.1 THROUGH E.6
EXPENSE AND SEWER USE CHARGE PROJECTIONS -
BOSTON
E-20
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SABLE E.1 BOSTON WATER *80 SEI. R tSStON
INFLATED DOLLAR EXPENSE PROJECTIONS FOR SITE 2 OJTF*LL ALTERNATIVE,
VRLUES IX $1000
FT FT ry FT FT FT F ’ FT FT FT FT FT FT Ft FT Ft FT
EXPE2SES 1957 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
er stln 5• $13372 $15480 $16254 $17066 $17920 118816 $19157 1207 $21782 $22871 124014 $25215 126476 121799 $29189 $30669 $32151
Indirect • 12,920 13,380 13.549 13,72? 13.913 $4,109 $4,314 14.530 14.756 14,994 $5,244 15,506 15,781 16,078 16,374 16,693 17,027
Renewal I Repl.ce. • 11,855 $2,147 $2,255 $2,368 $2,456 $2610 $2,741 1.2,8Th 13,022 13,173 $3,331 $3,498 $3,673 $3,856 14,049 $4,252 14,464
Bill Adjiatantu • 12,320 $2,686 $2,820 12,961 $3,109 13,264 $3,428 13,599 13,779 $3,968 14,166 14,315 14,593 14,873 $5,064 $5,317 15,583
Bad Debt Allow. • $310 $428 1450 1472 1496 $521 $347 $574 1603 1633 1664 1698 1733 1769 1800 1848 1890
Reserve Deposit, • $1,594 $1,845 11,938 12,034 $2,136 $2,243 $2,355 $2,473 12,5% 12,726 12,863 13,006 13,156 $3,314 13480 13,653 13,836
Local Debt 18,050 $7,050 $7,050 17,050 17,050 $1,050 $7,050 17,050 $7,050 17,050 $7,050 17,050 $7,050 $7,050 17,05 $7 05
JBTOTAL $30,481 133,016 $34,316 $35,678 $37,110 138,613 140,192 141,848 1 /.3,588 145,415 147,332 149,348 151,462 $53,681 $56,014 $58,462 $61,031
A erstIng -- $30,148 $38,690 $39,012 140,895 163,093 $30,988 $39,199 $41,500 143,090 151,730 166,979 168,040 111,642 175,014 $78,766 182,783
NURA Capital •. 115,301 $24,078 $37,123 $50,747 163,021 $55,031 $76,617 1104,103 $118,562 $179,252 $132,673 $133,859 1134,884 $134,804 1135,993 1137,255
T0TAL $19 413 145 649 162 768 $76 195 191 U2 1106 114 194 019 $115 816 $145 603 $161 652 $180 982 1199 652 1201 899 1206 326 1209 818 $214 757 $219 958
fl• tUtuuu CUSS 5 5 5 5 55 5W SUflSSSfl •UCtSSUtS 5 5 555 55CC Sflflfl=2 555555555 .55.55555 • 555 5n5. 555555555 555555555 555555555 555555555 .. 55555 5U fltS
TOTAL EXPENSES 149,894 178,465 197,084 $111,873 1128,752 1144,727 $134,211 $157,666 $189,191 $207,067 $228,314 $249,000 $253,361 1260,007 1265,032 1273,219 1280,989
Less Other R. .. $9,169 $5,317 15,583 $5,862 $6,155 16,463 16,786 17,125 $7,482 $7,856 18,248 18,661 19,094 19,549 110,026 110,527 $11,054
1 Required fro., Rate, $40,725 $73,148 191,501 $106,011 1122,597 $138,266 $127,425 $150,539 $181,209 $199,211 1220,066 1240,339 $244,267 1250,458 1255,806 1262,692 1269,935
I )
-a
2 Total Increase 79.612 25.092 15.86% 15.652 12.78% 754% 18.14% 20.71% 9.63% 10.47$ 9.212 1.632 2.53% 2.14% 2.69% 2.768
Note: • Iteew increased .vsi.lly for inflation by 5.02.
reflect, sppi-oxite siesiul debt service on outstsi ing bonds as of Sept. 1987; onticipeted additional local bond issues not Included.
••• item Increased for Inflation, does not include prior years surplus or federal grants after 1987.
Source: Adapted I rem NURA, STFP VII, 1987.
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TABLE F.? PROJECTED BWSC SEVEN RATES A FINANCIAL I ACTS
SITE 2 0.JTFALL ALTERNATIVE
FT FT FT FT FT FT FT FT ry y FT FT FT FT FT c v iv
RATE SCVECULE (I R 1000 0.1 F?) 198? l99 ) 1991 1992 1993 1994 1995 197/. 1997 1998 1999 2000 O0I 2002 2003 2004 2005
lit 19 ft/day 110:100 322693 :291 $30405 334290 131.602 137.334 565.065 149.405 154.577 159.603 160.579 162.113 163.441 165.149 166.945
neat 20 Cu ft/dey 110.210 118.339 122.940 126.577 130.736 134.664 131.946 137.741 145.555 149.943 155.172 160.254 161.239 162.791 164.132 165.858 167.674
neat 50 cu ft/day 110.320 118.536 323.187 126.864 331.061 135.037 132.290 138.168 166.066 150.682 155.766 160.904 161.899 163.648 166.823 166.568 168.403
neat 70 cu ft/day 310.630 118.734 123.434 127.150 131.398 135.611 132.635 138.554 146.537 151.020 156.361 161.553 162.559 164.164 165.516 167.218 169.133
neat 190 cu ft/day 110.340 118.931 123.681 127.436 131.729 135.181 132.979 138.961 147.028 151.558 156.955 162.202 163.219 164.821 166.205 167.98? 169.862
neat 250 CU ft/day 110.650 119.129 323.928 127.723 132.060 136.158 133.323 139.367 147.519 152.0% 157.549 162.851 163.818 165.497 166.8% 168.697 170.591
neat 700 cu ft/day 110.760 119.327 $24,176 128.009 132.391 136.531 133.667 139.774 148.009 152.654 358.146 163.500 164.538 166.174 167.587 169.406 171.320
neat 1700 cu fl/day 110.870 119.524 124.423 128.296 132.723 136.904 134.011 140.181 148.500 153.172 158.738 164.149 165.198 166.850 168.278 110.116 172.049
neat 3000 Cu ft/day 110.985 119.722 124.670 128.582 133.054 137.218 134.356 140.587 348.991 153.710 159.333 164.799 165.858 167.527 168.969 110.825 112.718
over 5999 cu ft/day 311.0% 119.919 124.91? 128.& 8 133.385 137.651 134.700 140.994 149.482 154.248 159.927 165.648 166.51? 168.203 169.640 171.535 173.507
A,vwal Cost for
ResidentisI, 10,000 cu ft/yr 1100 1180 1225 1260 1301 1340 1313 1370 $446 1489 1540 1590 1600 1615 1628 1645 $663
estI C rcist, 500.000 Cu ft/yr 16,523 $11,716 $14,656 116,980 119,63? 122,146 120,610 124,112 129,105 131,908 135,248 136,4% 139,125 $40,116 140,973 142,076 143,236
Large Cciauerciet, 5,000,000 CU ft/yr 154,988 198,767 1123,547 $143,138 1165,533 $186,688 1172,053 1203,261 1245,348 1268,980 1297,139 1324,512 1329,816 1338,175 1345,396 1354,694 1366,474
Source: Adapted frau NINA, STFP VII, 1987.
I J
I ’)
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TABLE £3 $05700 WATER ** WI ISSI0N
INFLATED I 0LLAB EXPENSE PROJCCTIONS F00 SITE 6 iXJT’ALL ALT ENAT:w,
VALIiS IN $1000
FT FT FT FT
1997 1998 1999 2000
$21,782 $22,871 $24,014 125 .215
$4,756 $6,994 $5,264 15,506
$3,022 $3,173 $3,331 $3,498
$3,779 $3,968 $4,166 $4,375
$603 $653 5664 5698
52,5% 52,726 $2,863 $3,006
$7,050 $7,050 $7,050 $7,050
$43,508 $45,415 $47,332 $49,348
$41,500 $43,090 151,730 166,979
$106,103 $118,562 $129,252 S132 673
$145,603 $161,652 $180,982 $199,652
S . •flSStflS SSSSflSSS
$189,191 $207,067 $228,314 $249,000
$7,482 $7,856 $8,248 $8,661
$181,709 $199,211 $220,066 $240,339
FT FT FT FT FT
2001 2002 2003 20% 2005
$26,476 $27,799 $29,189 $30,649 $32,181
$5,781 $6,070 $6,374 $6,693 $7,027
$3,673 $3,856 $4,049 $4,252 $6,464
$4,593 $4,823 $5,064 $5,317 $5,583
$733 $769 $808 $868 $890
$3,156 $3,314 $3,480 $3,653 $3,836
$7,050 $7,050 $7,050 $7,050
$51,662 $53,681 $56,016 $58,462 $61,031
$68,060 $71,442 $75,014 $78,764 $82,703
$133,859 $134,884 $134,806 $135,993 $137255
$201,899 $206,326 $209,818 $214,757 $219,958
SSS ••fl SUSS
$253,361 $260,007 $265,832 $273,219 $280,989
89,0% $9,549 $10,026 $10,527 $11,054
$244,267 $250,458 $255,806 $262,682 $269,935
2 Total i treaae
81.642 25.80% 15.89% 15.982 13.352 6.16% 0.012 20.712 9.632 10.678 9.21% 1.632 2.53% 2.142 2.69% 2.762
Note • Its ktrssaed sinsIly for Inflation by 5.0%.
reflects sgproslata sin aI debt service on outats lng boat as of Sept. 1987; anticipated a ltIonal local bad Issues not IncISed.
° itt. Increased for Inflation, does not Include prior year’s surplus or federal grants after 1987.
Source: Adopted fro. NURA, STFP Vii, 1987.
FT FT FT FT FT FT FT FT
EXPENSES 1987 1990 1991 1992 1993 1996 1995
Operating • $13,372 115:480 116:254 $17066 117:920 $18•816 $19,757 $20,744
Indirect • $2,920 $3,380 $3,549 $3,727 53,913 $4,109 $4,314 54,530
Renewal $ Raplaca. • $1,855 $2,147 $2,255 $2,368 $2,486 $2,610 $2,741 $2,878
Bill Adjuatanta • $2,320 $2,686 $2,820 $2,961 $3,109 $3,264 $3,428 $3,599
Bad Debt Allow. $370 $428 $650 $472 5496 $521 $567 $574
Reserve Deposits • $1,596 $1,865 $1,938 $2,034 $2,136 $2,243 $2,355 $2,473
Local Debt ° 58,050 $7,050 $7,050 $7,050 $7,050 $7,050 $7,050 $7 O5O
SUBTOTAL $30,681 $33,016 $34,316 $35,678 $37,110 $38,613 $40,192 $41,868
MMA Operating .. $30,148 $38,690 $39,072 $40,895 $43,093 $38,988 $39,199
NWRA Capital .. $16,127 $25,638 $38,963 $53,237 $66,547 $78,125 $76,617
9RTOTAL $19,413 $46,275 $64,328 $78,035 $96,132 $109,640 $117,113 $115,816
S •SSSSSSSS S 555
TOTAL EXPENSES $49,896 $79,291 $98,646 $113,713 $131,242 $148,253 $157,305 $157,664
Less Other Rave. - 59,169 $5,317 $5,582 $5,862 $6,155 $6,463 $6,786 $7,125
Ba iIred f row Rates $40,725 $73,974 $93,061 $107,851 $125,087 $141,790 $150,519 $150,539
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TABLE E.4 PROJECTEO BVSC SE1ER RATES AND FINANCIAL I ACTS
SITE 4 OJTFALL ALTERNATIVE
FT FT FT FT FT FT FT FT FT FT FT FT FT IT FT FT FT
IAIE SCPEVULE (PEt 1000 ai FT 957 1990 1991 1992 1993 199.. 1995 10% 1997 1998 1999 2000 20C1 2002 2003 20 1)4 200,
Ist l9c uftld.y $10100 $18346 123USD $26747 $31022 $35165 $37329 $37334 $45065 $49405 $54577 $59605 $60529 $62115 $63441 $65149 166945
next 20 Cu ft/day 110.210 118.546 123.331 127.039 131.360 135.548 137.736 137.741 145.555 149.943 155.172 160.254 161.239 162.791 164.132 165.858 167.674
next 50 cu ft/day 110.320 $18746 123.582 127.330 131.698 135.931 138142 138.148 146.016 150.482 155.766 160.904 161.899 163.468 164.823 166.568 168.403
next 70 cu ft/day 110.430 118.945 123.834 127.621 132.036 136.314 138.549 138.5% 146.537 151.020 156.361 161.553 162.559 164.144 165.514 167.278 169.133
next 190 cu ft/day 110.540 119.145 124.085 127.913 132.374 136.697 138.956 138.941 147.028 151.558 156.955 162.202 163.219 164.82) 166.205 167.987 169.862
next 250 cu ft/day 110.650 119.345 124.336 128.204 132.712 137.080 139.362 139.367 147.519 152.0% 157.549 162.851 163.878 165.497 166.8% 168.697 170.591
next 700 Cu It/day 110.760 119.545 18.588 128.495 133.049 137.463 139.769 139.774 148.009 152.634 158.144 163.500 164.538 166.174 167.587 169.406 171.320
next 1700 a, ft/day 110.870 119.745 124.839 128.787 133.387 137.646 140.175 140.181 148.500 153.172 158.738 164.149 165.198 166.850 168.278 170.116 172.049
next 3000 Cu ft/day 110.980 119.944 125.091 129.078 133.725 138.229 140.582 140.587 148.991 153.710 159.333 164.299 165.858 167.527 168.969 170.825 172.778
over 5999 cu ft/day 111.090 120.144 125.342 129.369 134.063 138.612 110.988 140.994 149.482 154.248 159.927 165.448 166.517 168.203 169.660 171.535 173.50?
A,vxjat Cost for
t.sldantfal , 10,000 Cu ft/yr 1100 1182 1229 1265 1307 1348 1370 1370 1446 1489 $340 1590 1600 $615 $628 $645 1663
tt C uercIat , 500,000 Cu ftFyr 16,523 $11649 $14,906 $17,275 120,035 122,711 124109 124.112 129.105 131,908 135,248 138,4% 139,125 140,116 140,973 142,076 143,236
Large C rcI.t , 5.000,000 Cu ft/yr 154,988 199,882 1125,654 1145,623 1168,896 1191,449 1203,234 1203,261 1245,348 1268,980 1297 .139 1324,512 1329,816 1338,175 1345.3% 1354,694 1364 .47k
Source: Adapted fros STFP VII • 1987.
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TABLE E.5 BOSTON IMTER *ie RWR ISSION
INFLATED DOLLAR EXPENSE PROJECTIONS FOR SITE 5 (IJTFALL ALTERIIATIVE,
VALUES II $1000
FT FT FT FT FT rv F’ FT FT FT FT FT FT FT Fl FT
EXPENSES 1987 1990 1991 1992 1993 1994 1995 19% 1997 1998 1999 2000 2001 2002 2005 200’. 2005
wrating • $13,372 $15,480 116.254 111,066 $17,920 $18,816 $19,737 $20,744 $21,782 $22,871 $26014 $25,215 $26,476 $27,799 $29,189 130,449 $32,181
Indirect • $2,920 $3380 $3,549 $3,727 $3,913 $4,109 $4,314 $4,530 $4,156 $4,994 $52M $5506 $5,781 16,010 16.374 16,693 $7,027
Rensv,( $ Rapiec.. • $1855 $2,147 $2,255 $2,368 $2,486 $2,610 $2,741 $2,878 $3022 $3,173 $3531 $3,498 $3,673 $3836 $4,019 $4,252 $4444
Sill AdJu,tsnt. • $2,320 $2,686 $2820 $2,901 13,109 $3,264 $3,628 $3,599 13,779 13,968 14,166 14,315 14,593 14.823 15,064 $5,317 $5,583
Bid Debt Aiicv. • $370 $428 $450 $472 $496 $521 $547 $574 1603 $635 $644 1698 1733 1769 $808 1848 1890
Reserve Deposits • $1,596 $1,145 $1,938 12,034 12,136 $2,243 $2,355 12,473 12,5% 12,726 12,863 13,006 $3,156 $3,316 $3480 $3,653 $3,836
Loc.i Debt • 18,050 17,050 $7,050 $7,050 17,050 17,050 sr•oso $7,050 17,050 17,050 $7,050 17,050 17,050 17,050 17,050
80BTOT*L $30,481 $33,016 $34,316 $35,678 $37,110 $38,613 140,192 $41,845 $43,588 $45,415 $47,332 $49,345 $51,462 $53,681 $56,014 $58,462 $61,031
RI A ,erstIng 130,168 $35,690 139,072 $60,895 143,093 $38,988 $39,199 141500 143,090 $51,730 166,979 168 .060 $71,442 $15,014 $78,144 182,103
ISdRA Capital $16,514 $26,369 139,824 $54,403 $68,198 180,499 191,619 $104,103 $118,562 $129,252 $132,673 $133,859 $134884 $134,804 $I35 993 1137.255
RI T0TAL $19,413 $66,662 $65,059 $78,096 $95,298 $111,291 1119.487 1130.818 1145.603 $161,652 1180,982 $199,652 $201,899 $206,326 1209,818 1214,157 1219,958
nfln.n flnunn m a c u n flnnn. flea..... .a.a.caa. aaa.an.a aaaa.aan flame.... Sea,..... ......n. ......n. us...... fl.afl.aU n.a. s .a. 55 flflflafl
TOTAL EXPENSES $49,094 $79678 $99,373 $116,574 $132,408 $149,906 1159,679 $172,666 $189,191 1207,067 $228,314 $249000 1253,361 $260,007 $265,832 $273,219 $280,989
Less Other Revs. - $9,169 $5,317 $5,583 83.862 16,155 16,463 16.786 $7,125 $7,482 17856 18,248 $8,661 $9,096 $9,549 $10,026 $10,527 $11,054
Rs paIr.d fre. Rates $60,725 $74,361 $93,792 $108,712 1126,253 $143,441 $152,893 $165,541 $181,709 $199,211 $220,066 1240,339 $244,267 $250,458 1255,806 1262,692 1269,935
C T ,
I Total tnc,e.se 82.59% 26.13% 15.91$ 16.14$ 13.61% 6.59% 8.27% 9.71% 9.63% 10.47% 9.21% 1.63% 2.531 2.14% 2.69% 2.76%
I -n
Rote: • it incresged .‘esid(v for infl,tian by 5.0%.
reflect, rosfe.te .vs l debt service an outst Iep band, is of Sept. 1987; anticIpated s iticnoi (ccii band Issue. not incluled.
Ite. increased for inf titian, dee. not Inclt& prior )esrs surplu, or federal grant, af ter 1987.
Source: Adapted fre. A, STFP VII, 1987.
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TABLE E.6 PROJECTED BVSC SEVER RATES A 1 F!IAJICtAL I ACTS
SITE 5 OJTFALL ALTERNATIVE
iT ‘T FT FT FT FT F FT FT FT FT FT FT FT FT FT FT
RATE SE1E(fl.E (PtR 1000 0.1 FT) 1987 1991J 1991 1992 19 .’3 1994 1995 1996 199? 1998 1999 2000 2101 2052 2003 2006 2005
1st 19 cu ft/dr.’ 810 100 118 642 123 261 126 961 131 311 135 574 137 918 141 055 $45 065 149 405 154 577 159 605 $60 579 162 115 163 441 165 169 166 945
next 20 c i i ft/day 110.210 118.643 123.514 127.255 131.652 135.962 138.331 141.502 145.555 149.963 155.172 160.254 161.239 162.791 164.132 165.858 167.674
next 50 cii ft/day 110.320 118.864 123.768 127.548 131.993 136.349 138.744 141.969 146.066 150.682 155.766 860.906 161.899 163.468 164.823 166.568 168.403
next 70 cii ft/day 110.430 119.065 124.021 127.842 132.335 136.736 839.157 142.397 166.537 151.020 156.361 161.555 162.559 164.144 165.514 167.278 169.133
next 190 cii ft/day 110.540 119.245 124.274 128.136 132.676 137.126 139.570 142.864 147.028 151.558 156.955 162.202 163.219 164.821 166.205 167.987 169.862
next 250 c i , ft/dr.’ 110.650 119.446 124.528 128.429 133.017 137.511 139.983 143.291 147.519 152.096 157349 162.851 163.878 165.497 166.8% 168.697 170.591
next 700 Cu ft/day 110.760 119.647 124.781 128.723 133.358 137.899 140.3% 143.738 148.009 152.634 158.144 163.500 164.538 166.174 167.587 169.406 171.320
next 1700 cu ft/day 110.870 119.848 125.034 129.017 133.699 138.286 140.809 144.185 148.500 153.172 158.738 164.149 165.198 166.850 168.278 170.116 172.049
next 3000 cii ft/day 110.980 120.049 125.288 129.310 134.040 138.674 141 .222 146.632 148.991 153.710 159.333 164.799 165.858 167.521 168.969 170.825 172.778
over 5999 cii fuday 111.090 120.250 125.541 129.604 134.381 139.061 141.635 145.079 149.482 154.248 859.927 165.448 166.517 168.203 169.680 171 .535 173.507
A,va t Cost for
RosidentIsi, 10,000 cii ft/yr 1100 1183 1230 1267 1310 1352 1375 1406 1446 1489 1540 1590 1600 $615 1628 1645 1663
tI C rcI.t , 500,000 cii ft/yr 16,523 111,911 115,023 117413 120,222 122,975 124,489 $26,515 129,105 131,908 135,248 138,4% 139,125 $40,116 $40,973 142,076 143 .236
Large C nerc1.t, 5,000,000 cii ft/yr $54988 1100,405 1126641 $166,786 1170,471 1193,678 1206,440 1223,519 1245,348 1268,980 1297,139 1324,512 1329,816 $338,175 1345,396 1354694 1364,474
1curcT A ted fros A, STFP V II, 1981.
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TABLES E.7 THROUGH E.12
EXPENSE PROJECTIONS AND SEWER CHARGES —
NEEDHAM
E-27
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TABLE F.?. 1 01 NEFDN*M 98OJECTEO EXP$USES
SITE 2 WTFALL ALTEABAUVE,
VALUES IN $1000
FT FT FT FT FT FT FT FT P FT FT F’ FT FT FT FT FT
LOCAL EXPENSES 1987 1990 1991 1992 p993 1994 1995 1996 1997 1990 1999 2000 2001 2002 2003 2004 2005
Ofrict Expense. $580 $672 $705 $741 1778 181? 1857 $900 $945 $993 $1,962 $1,094 $1,149 $1,201 $1.26? 11,330 $1,397
Indirect Expenses $181 $209 $220 $231 $242 $254 $267 $280 $294 $309 $324 $341 $358 $376 $394 $414 $435
T0TAL $761 $881 $925 $972 $1,020 $1,071 - $1124 $1,180 $1,239 $130 $1,366 $1,435 $1,507 $1,583 $1,661 11,746 11.832
IU A sr.ting $1,146 $1,410 $1,485 $1554 11,638 $1,482 $1,490 $1,577 $1,638 $1,906 $2,545 $2,586 12,715 12,851 12,993 83,143
Nima Capital - $675 $1,063 11,638 $2,240 $2,782 $2,429 $3,382 14,595 $5,233 15,705 $5,856 $5,909 $5,954 $5,950 $6,003 $6,059
SUBTOTAL $780 $1,821 $2,533 $3,123 $3,796 14,420 $3,911 $4,872 $6,172 $6,871 $7,671 $8,401 $8,495 18,669 18,801 18,996 19,202
.5_a.... •..S..Ufl .Saflfl.a ass.. . ... •...n... flu...... •.a....a. flt.aflugu s 5 5uflna ..fl...n ass...... ssn...n •flaaaSn •flsnsua flauSfl S ..an..n n .una .
TOTAL EXPENSES $1,521 $2,102 $3,658 14,095 14,814 15,49? $5,035 $6,052 17,61? $8,173 $9.03? $9,836 $10,002 $10,252 $10,462 $10,740 111,034
$ewer Iste Expenses $463 $1,524 $2,236 $2,826 13,491 $4123 $3,614 16,515 15,815 16,574 $7,374 18,104 18,1% 18,372 18,504 18,699 18,903
Property tsx Expenses $1,058 $1,178 $1,222 $1,269 $1,317 $1,368 $1,421 $1,477 $1,536 $1,599 $1,663 $1,732 $1,804 $1,880 $1,958 12,941 12,129
I Incrssss in Bste Expenses -- 229.228 46.678 26.428 23.748 17.902 -12.352 26.582 28.622 11.902 12.178 9.902 1.16$ 2.128 1.582 2.292 2.372
8 I, re..e In STe.” Expense. -. 11.34$ 3.748 3.858 3.788 3.878 3.878 3.948 3.998 4.108 4.002 4.158 . 4.168 4.21$ 4.15$ 4.248 4.318
Source! Adapted fro. m*A, SUP VII, 190?.
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TAULE E.8 PROJECTED PREDRAU SE’ R RATES *00 FINAACIAL I ACTS
SITE 2 GJTFALL ALTERNATIVE
FT FT F t FT 1? FT FT FT FT FT FT FT FT FT FT FT py
1987199019911992199319% 19951996199719% 9999 2000 2009 2002 2003 2004 2005
i ;;:; ;:; $2.20 $2.72 $3.21 $2.8; 53.56 $4.;? $5.91 $5.73 $6.30 $6.37 $6.51 $6.69 16.76 16.92
$36 SIlLS? $973.83 $219.75 $271.93 $320.60 $201.01 $355.70 1636.00 $591.15 $573.36 1630.12 $637.43 $630.95 1661.22 $676.38 $692.40
$107 $352.2? $516.66 $653.15 $800.23 $952.90 $835.23 $ 1,057.21 $1,357.72 $9,599.26 $9,704.94 $1,872.85 $9,894.5? $1,934.78 $1,965.29 $2,010.35 $2,057.96
SEVER TAN RATE
Totsi Veluetlon ($9000) $3100000$3%5IO? $4 297,516 $4 554,917 $6 919 310 $5 312655 $5 737686 $619691416 692 66787 226 081 $7006 327 18 430834 $9 905300 $9 833 724 $10 620 422 $19 470056 $12 387660
Sewer Tue per $I 50.34 $0.30 $0.29 $0.28 $0.2? $0.26 $0.25 $0.24 $0.23 $0.22 $0.29 $0.29 $0.20 $0.99 $0.98 $0.18 10.17
VeliatIon*v . Imie $298 $344 $36? $300 $399 $419 $440 $462 $485 $509 $534 $561 $589 $619 $650 $682 $796
A ,vea.I Sewer Tee Aeees nt
for the Averege N $909.70 $103.7? $186.89 $103.8? $106.82 $107.89 $108.9? $910.92 $111.31 $112.60 $113.76 $115.25 $196.70 $118.34 1919.84 $121.36 $123.06
Vstuutlen•Lerge tier $375 $434 1456 $479 $503 $528 $554 $582 $611 $661 $673 $707 $742 $700 1899 $860 $902
*snj.t Sewer Tee A,ee,u nt
for the Averege tier $927.98 $130.92 $932.12 $133.45 $134.66 $135.95 $137.20 $158.72 $940.23 $161.00 $943.37 $943.24 $147.09 $149.92 $150.99 $153.03 $955.02
Told A,ve t Sewer aierge.
Averege Single Fewily N
Uuer thug. $36 $119 $174 $220 $272 $321 $289 $356 $457 $511 $573 $630 $637 $651 $669 $676 1692
Property Iu $902 $904 $905 $106 $107 $908 $909 $910 $999 $113 $996 $115 $91? $998 $920 $929 $923
TOTAL $2228279 : : . :
Totut Aieenl $e r
Lerge Volta, Veer
Uewr thurge $107 $332 $59? $633 $808 $953 $835 $9,057 $1,358 $1,519 $9,706 $9873 $1,895 $9,935 $1,965 $2,010 12,058
Property Tee 1128 $931 $132 $933 $935 $936 $937 $139 $940 $142 $143 $943 $947 5149 $151 $953 $955
TOTAL $235 $483 1649 $787 $963 $9,089 $9?? $1,996 $1,498 $1,669 $1,868 $2,096 . $2,862 $2,084 $2,116 $2,163 $2,293
A IML SItU USE CHARGE
Ret• r 100 cf
90,000 Cu fllve.r
30,000 cu ftlyeer
Saurce: Adupted fra. W4$A, STFP VII, 1987.
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TABLE £9 OP NEEVNAN PROJECTED EXPENSES
SITE 4 JTFALL ALTERNATIVE,
VALUES IN 11000
FT FT IT FT FT FT FT FT FT FT FT FT VT F? F? U FT
LOCAL EXPENSES 1907 1990 1991 1992 1993 1994 I9SS 1996 1997 ‘998 1909 2000 2001 2002 2003 2004 2005
Direct Eepe wes $550 $672 $705 $741 $775 9017 $857 $900 $9 $993 $1,042 $1,096 $1,149 $1,207 $1,267 $1,330 $1,397
Indirect Eiipei e. $181 $209 1220 $231 $242 $254 $267 $280 1294 1309 1324 $341 $355 $374 $394 $414 $435
TOTAL $761 1881 $925 $972 $1,020 $1,071 $1,124 $1,180 $1,239 $1,302 $1,356 $1,435 $1,507 $1,583 $1,661 $1,744 $1,532
m*A er.tin .. $1,146 $1,470 $1,455 $1,554 $1,638 $1482 $1,490 $1,577 $1,638 $1,986 $2,545 $2,356 $2,715 $2,851 $2,993 $3,143
4RA CepIt.t $712 $1,132 $1,719 $2,350 12,938 $3,448 13,382 $4,595 $5,233 $5,705 $5,856 15,909 $5,954 $5,950 $600
t0TAL $760 $1,855 $2,602 $3,296 $3,904 $4,576 $4,930 $4,572 $6,172 $6,871 $7,671 $8,401 $8,495 $8,569 18,801 $8,994 $9,202
n.n.... ......n. .....u... 5c 5s 5 0 •n..fl.. .....fln •...==.u. stun.... n....... •5 S •SsSSflut ...u....S u . n .. ... n....... as...... .....n.. •flSR R U
TOTAL EXPENSES $1,521 $2,739 $3,527 $4,176 $4,924 $5,647 $6,054 $6,052 $7,411 $8,173 $9,037 $9,536 $10,002 $10,252 $10,442 $10,740 $11,034
Siwer Net. £zpevwes $463 $1,561 $2,303 $2,907 $3,607 $4,229 $4,633 $4,375 $3,875 $6,574 $7,374 18,104 18,195 18,372 18.505 18,699 18,905
Property Tee Eipe e. $1,058 $1,178 $1,222 $1,269 $1,317 $1,368 11,421 $1,477 $1,536 $1,599 $1,663 $1,732 $1,504 $1,880 $1,958 12,041 $2,129
S Ii resei in R.te Eepeiwes 237.09% 47.66% 26.16% 24.07% 18.62% 8.29% .1.27% 28.42% 11.908 12.175 9.90% 1.16% 2.12% 1.58% 2.298 2.375
S Iv ree,e In 5 Te* Expe ee 11.345 3.74% 3.855 3.785 3.875 3.878 3.94% 3.998 4.105 4.001 4.155 4.165 4.21% 4.155 4.245 4.315
1 rce: Adepted V r N*A, STFP VII • 1987.
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TA$LE 1.10 PIOJECTED NEEDIIAN 88W1 PATES *80 FIN*EI*L t *CTS
SITE 4 WTF*LL ALTEINATIVE
86181 l ChARGE
Pete per too C
10.000 cu ftlyear
30,000 cu I tlyear
PT FT FT FT FT F T PT PT PT FT FT FT IT IT Ft
1981 1990 1991 1992 1993 t99 . 1995 1996 1997 1990 1999 2000 200? 2002 2003 2006 2005
P2 8.) $3.33 $3.60 13t6 14.57 15.11 s;.n 16.30 eó.si 16:;? 16.61 16.76 $6.92
$36 $121.35 $179.19 $226.07 $200.68 $332.70 $360.27 $355.70 $456.80 $5I1.15 1573.36 1630.12 1637.63 1650.95 $861.22 1676.58 1692.40
$107 $360.69 $532.58 $671.92 1833.64 1988.87 $I ,070.80 $1 ,057.21 $1,357.72 11,519.26 11,704.14 $1,872.85 11.89457 $1,934.78 Sl ,965.29 12,010.35 12,057.96
86181 TAX PATE
Total ValwetI i ($1800) 13100.000 13,905,107 $4,217,516 14,554,9?? $4,919,310 15,312,855 15.737886 16,116,914 16,692,867 17,228,961 17.806.327 $8,430,834 $9,196,500 19.833724 110,020,422 $11,479,056 $12387660
Sewer Tax per $1080 10.34 10.30 10.29 $0.28 10.27 10.26 10.73 10.26 $0.23 10.22 $0.21 $0.2? $0.20 10.I9 10.18 $0.18 $0.??
V.ltatlen-Avg. Iciwe 1298 1344 1362 1380 1599 1419 1460 1462 1485 1509 1534 1561 $589 $619 1650 $862 $716
A,vx t Sewer Tao Aauei nt
for the Average N $101.79 1103.77 $106.89 1105.81 1106.82 1107.89 1100.97 $?10.l2 $111.3? $112.60 1113.76 $115.25 $116.70 $118.34 $119.84 $121.36 $123.06
Val.atlonLarge Uax, $375 1434 1656 167? 1503 1528 $554 1582 16?? 164? 1673 1707 1742 1796 1819 $860 $902
Aivxapl Sewer Tax Auee nt
for the Average tiger $127.98 $130.92 $132.12 $133.45 $134.66 $135.95 1137.20 1138.72 $160.35 1I4 18P $14357 $141.24 $147.01 $149.12 1150.99 1155.03 $155.02
total A.veat $iwsi O argee
Average Single F 1 ty News
l er Ot.rg.
u Property Tao
LA)
-a
TOTAL
Total Am l Sewer Chargee
Large Vott e Uger
$36 $12? $179 1226 1280 $333 $360 1356 1457 15?? 1573 1630 1637 $651 $66? $676 $692
1102 1106 $196 1106 1107 1108 1109 1110 1??? $113 1116 $115 1??? $118 1120 $121
1138 1225 12W. 1332 1387 1441 1469 $666 1568 1624 $687 $745 $754 1769 111? 1798 $815
$107 $36? 1533 1672 1834 1909 $I ,071 $1,057 11,358 $1,519 11,104 $1,873 $1,895 11,935 11,965 $2,010 12.058
1I28 $13? $132 $133 $135 $136 $137 $139 1160 1142 $163 $165 $147 1149 1151 1153 $155
1233 $492 1665 1805 1968 $1,125 $1,208 $1,196 $1,496 11,661 $1,868 $2,018 $2,062 $2,086 $2,116 $2,163 12,213
Ussr Charge
Property Tax
TOTAL
Scurce: Pthpted free 8* , SUP VII, 1987.
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TAOLE Eli T OF NEEDNAR PIOJECTED EXPENSES
SITE 5 UITFALL ALIERNATIVE ,
VALUES IN $1000
FT FT FT FT FT FT F? FT FT F? F? FT FT FT FT FT FT
OCM EXPENSE S 1987 1990 1991 1992 19931994 1995 199619971990 1999 2000 20 7002 2003 20% 2005
OIrct Expose, $580 1672 ;; .945 , :;; : ; $1 .3fl
Indirect Expenses $181 1209 1220 1231 $242 $254 $267 $280 $294 $309 $324 $341 $358 $376 $39 1 . $414 $1.35
T0TAL $761 $881 $925 $972 11.020 $1,071 11.124 11.180 11.239 $1,302 $1,366 $1,435 $1,507 $1583 $1,661 $I ,T $1,832
IRMA ,sr.t1n $1,146 .1.470 $1485 $1,554 $1,638 $1,482 11,490 11.577 $1638 $1,966 $2,545 $2586 12,715 12,851 12.993 $3,143
IRMA C.pltsl $729 11,164 $1,757 12,402 $3,011 13,553 $4,044 $4,595 $5,233 $5,705 $5,856 $5,909 $5,954 $5,950 16,003 16.059
MJSTOTAL 1760 $1,875 12,634 13,242 $3956 14.649 $5,035 $5,534 16.172 16,871 $7,671 $8,401 18,495 18,669 $8,801 18,9% 19,202
fiflSSSfl mu..... an..... n....... Sn...... • ..n... sat...... ...n...u a... .n.. flu.. . ... flu...... n s a . .... ......... n.n.... n....... .n.n... m..n..
TOTAL EXPENSES $1,521 12,156 $3,559 14 .214 14,976 15.720 16,159 $6,714 $7,411 $8,173 $9,037 $9,836 $10,002 $10,252 $10,462 $lO 74O $11,034
Sei r late Expenses $463 11,578 12,337 12,945 13659 $4,352 14,758 15 ,237 $5,815 $6,574 17374 18104 18,198 18,372 $8504 $8,699 $8,905
Property Ts* Expenses 11,058 $1,178 $1,222 $1,269 11,317 11.368 11,421 $1,477 $1,536 $1,599 $1,663 $1,732 $1,804 $1,880 $1,958 12,01.1 12,129
2 ti ress. In t.te Expsnse , •• 240.792 48.10% 26.05% 24.222 18.94$ 8.882 10.52% 12.19% 11.90% 12.17% 9.90% 1.168 2.12% 1.582 2.29% 2.37%
2 Incise,. In Tax Expenses 11.342 3.768 3.852 3.782 3.872 3.872 3.942 3.99% 4.10% 4.00% 4.15% 4.16% 4.21% 4.152 4.24$ 4.312
lOixce: Adopted fr IROA, STFP VII • 1987.
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TAIU £12 PIOJECTED NEEDNAN *WR NATES I FINAICIAL TIWACTS
SITE 5 TFALL ALTERNATIVE
FT FT FT FT FT F! FT F! F— FT F! I! FT F? F! FT
1987 1990 199t 199 1993 1994 1995 1996 1997 1998 1999 2000 200, 2002 2003 2004 2005
36 11:82 II2i $3.38 $3.68 $4.0? $4.57 $5.11 $5.73 16.30 16.37 $6.’1 $6.61 $6.76 16.92
$36 $122.68 $181.69 $229.02 $290.48 $338.37 $368.42 1407.18 1456.80 $511.15 $573.36 $630.12 $637.63 1650.83 1861.22 1676.38 $692.40
$107 $364.44 $540.03 1680.71 1865.54 $1,005.72 $1,095.02 $1,210.24 $1,357.72 $l 5I9.26 $1,704.14 $1,872.85 $1,896.37 $1,934.78 $1,965.29 12,010.35 $2,057.96
ICIU TM lATE
Total .l;flcn ($1000) 13,100,000 13 , .107 14.217.516 $6,554,917 16.919.310 15.312,855 93,737,884 $6,196,914 16.692,667 $7,228,081 17 .806,327 18,430,834 19 .103,300 99,883,724 $10,620,422 111,470,036 $12,387,660
Sever Tee per 11000 10.34 10.30 10.29 10.28 10.2? 10.26 10.25 10.24 10.23 10.22 10.21 10.21 10.20 10.19 10.18 10.18 10.1?
ValwtIon-Av . Now, $290 $344 $362 1390 1399 $419 $440 $462 $485 $509 $534 $561 1589 1619 1650 1682 $716
Amal Saver V i i Asseent
for the Average Now $101.70 $103.7? $190.89 $105.8? $106.82 1107.89 $108.97 $110.12 $111.31 1112.60 $113.76 $115.25 $116.70 $118.36 $119.84 $121.36 $123.06
Vatwtlon-Lergs User 1375 1634 1456 $479 1503 1528 1554 $582 1611 $641 1673 1707 1762 1790 1819 1860 1802
A,viI Sever se Ase.ant
for the Average User $127.88 $130.82 $132.12 $133.45 $136.66 $135.95 $137.20 $138.72 $140.23 $161.90 $145.37 1165.24 1167.01 $149.12 1150.99 $153.03 $155.02
m UserOi.rge $36 $123 $182 $229 $284 $338 $368 $407 $457 $511 $573 1630 1637 1651 $661 $676 $682
• Property Ta* $102 $104 1105 11% 110? 1108 1109 $110 Sill $113 $116 IllS II I ? SilO $120 $121 $123
I_.J
TOTAL $138 1226 1287 1335 $391 $446 $477 $517 1568 1624 1687 1765 1154 1769 1781 1788 1815
Total ival liver Charge.
Large Volow User
User Ow ’g. $107 $365 $540 1601 $846 l1, $1,095 $1,210 $1,358 11 3l9 $I 704 $1,873 $1,883 $1,935 $1,965 $2,010 $2,038
Property Via $128 $131 $132 $133 1135 $136 $137 $139 $160 $142 $145 $145 $16? 1149 1151 $153 1155
TOtAL 1233 $496 1672 1814 $980 $1,142 11.232 $1,369 $1,498 $1,661 11,908 $2,018 52,842 $2,056 12,116 $2,163 $2,213
Source: Adopted f rev APJ, STFP VII • 1947.
FJNIML IIWI USE 188802
late per 100 ci
10,000 cv ftFpear
30,000 cv ftlyesr
Total AivusI lever Charge.
Average SIngle F1 11y Now
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APPENDIX F
SCREENING AND DEVELOPMENT OF ALTERNATIVES
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APPENDIX F
SCREENING AND DEVELOPMENT OF ALTERNATIVES
The purpose of this appendix is to select the discharge location, outfall cond i:
construction, inter-island conduit construction and diffuser configuration
alternatives to be evaluated in detail in Chapter 5 of’ this Draft SEIS. A screening
process began with the full range of options for discharge location, conduit
construction and diffuser configuration. Screening criteria were identified and
applied to each of these items to narrow the range of suitable options for detailed
evaluation.
Analyses conducted by MWRA for the Deer—Island Secondary Treatment Facilit,ies Plan
(STFP) were reviewed and used during the screening analysis of this Draft S S.
This level of detail was considered adequate for the screerlng process. For
alternatives selected for detailed evaluation, separate analyses were conducted by
EPA in Chapter 5 of this Draft SEIS.
F.l DEFINITION OF “NO ACTION”
Consideration of the “No Action” alternative is required of EPA by regulations
adopted pursuant to the National Environmental Policy Act of 1969. In the case of’
this Draft SEIS, “No Action” refers to the continued discharge of’ effluent to Boston
Harbor through the existing Deer and Nut Island outfalls (Figure F.1.a).
The Record of Decision (U.S. EPA, 1985) for the siting of’ MWPA’s secondary
wastewater treatment plant determined that all treatment will be conducted on Dee”
Island, and that the Nut Island wastewater treatment plant (W%4TP) will be removed
and replaced with a pump station and headworks. “No Action” implies that there
would be no method of’ conveying wastewater from Nut Island to the Deer Island
WWTP. An inter-island conduit is a necessary feature of MWRA’s Secondary Wastet ater
Facilities Plan and therefore. “No Action” concerning the inter—island conduit would
be unacceptable.
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0 ,5
0.5
SLUDGE
DISCHARGE LINES
I -
STATUTE MILES
0.5
NAUTICAL MILES
FIGURE F.1.a. EXISTING EFFLUENT AND SLUDGE DISCHARGE LOCATIONS
OF THE DEER AND NUT ISLAND WASTEWATER TREATMENT PLANTS
0.5
ISPECT* LE
1 )IS AP
IS AN
SLUDGE DISCMA Gt LINE
ç LOVEI. L
$ALLODS
SAND
\GED GES
,CAOS
* E 1’
ISLAND
SOURCE: MWRA STFP , 1987
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“No Action” related to a new effluent outfall system implies that the waste ater
from the improved primary Deer and Nut Island WWTPs would continue to be discharged
through the existing Deer and Nut Islana WWTPs outfalls located in President arid
Nantasket Roads, respectively. The numerous pollution sources to Boston Harbor have
produced a highly stressed ecosystem and an accumulation of bottom sediments witri
high toxic concentrations and oxygen demand (U.S. EPA 1985a). The “No Act or.”
alternative of continued discharge would further degrade the quality of BOStOn
Harbor. Therefore, “No Action,” related to the effluent outfall systeir, is a
unacceptable alternative.
F.2 DIFFUSER LOCATION ALTERNATIVES
Completion of the EIS for siting of wastewater treatment facilities for Bosto
Harbor resulted fri a decision to build a secondary facility at Deer Island and
discharge the effluent east of Deer Island. It was concluded that actLal
designation of the discharge site was not necessary for the determination of the
plant location. The EIS did not consider alternatlve discharge locations uz
concluded that an acceptable site for discharge of secondary effluent could be
designated. The development of alternative locations, evaluation of the
alternatives and designation of a recommended discharge site was to be part of the
continued NEPA process represented by this Draft SEIS.
F.2.1 SCREENING PROCESS
The screening process began with the entire study area of the marine environrer:
east of Deer Island as defined in the secondary facilities sitng EElS. The object
of the screening process was to define potentially acceptable discharge locations
for detailed evaluation. With the exception of the first five years of operation.
the diffuser will discharge secondary effluent throughout its design l:fe.
Therefore, the discharge of secondary effluent was used to establish the area of
potentially acceptable discharge sites. Sites were then selected for deta ie3
evaluation of impacts for both primary and secondary effluents in Chapter 5 and
Appendices A, B, C and D of this Draft SEIS, based on the results of this screeni
process. After selecting the discharge sites for detailed evaluation, an aralysis
was conducted to determine whether the five year interirr primary efflue’t d sc arge
F-3
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should occur at the existing discharge location in President Roads or at or.e o ’ tre
alternative discharge sites (Section F.2.1i ).
Every step in the screening process had the potential for being iterative, if
rigorous analyses at any step contradicted conclusions made during previous ste:.s.
then the process was repeated. At every milestone in the screenlng process. t e
decision to either move forward or refine previous analyses was given stror g
consideration. This iterative approach kept the screening process flexible t..r le
narrowing the alternatives by eliminating those that offered few benefits or were
predicted to have significant adverse impacts.
F.2.1.1 First Secondary Effluent Site Screening Step: Landward Boundary
The selection of an area of’ potentially acceptable secondary efflLaert discbar e
locations consisted of two steps. At each step, the area under consideration was
evaluated to distinguish it as either unacceptable or potentially acceotable us r.g
both available data and a set of’ predetermined criteria in the evaluation. The
object of the first screening step was to define the landward boundaries of an area
of potentially acceptable secondary effluent discharge location alternatives. fl-c
object of the second step was to establish the eastern or seaward bourcary
encompassing this area.
F.2.1.1.1 Landward Boundary Screening Criteria. The criteria of the first
screening step were selected to eliminate areas which clearly could not (1) rov ce
a min muzn specified initial dilution, (2) protect public health and aquatic life, or
(3) avoid sensitive or unique resources. The screening criteria were derived fro—
review of MWRA criteria; public, regulatory and academic input; and indeperce :
technical evaluations.
Initial Dilution Potential. The potential for an area to have a sufficie’it in :
dilution is critical in determining the landward boundary of the area of potentaally
acceptable secondary effluent discharge sites. Achievement of water qual tv
criteria or standards is, in part, based on the iritial mixing w iich occu”s wher. an
effluent is discharged. Initial dilution results from the rapid entrainment of
ambient water into the turbulent buoyant plume produced by the discharge from tne
F_Lt
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diffuser. This rapid entrainment ends when the plume reaches the surface or ar
intermediate maximum height of rise where the plume density equals that of the
ambient water. An intermediate height of rise occurs when the ambient dilutior
water is vertically stratified, that is, a warmer less saline upper layer overlies a
colder, lower layer. Then the effluent plume will rise through the lower layer tc
the pycnocline (the point at which the transition in density occurs) where it
become trapped under the warmer, upper layer of water.
The potential to provide a minimum initial dilution of 50:1 (seawater to effluer t)
was considered to be a reasonable first-cut at establishing a landward boundary. Ar
initial dilution of 50:1 was chosen to represent the order of magnitude of the
minimum acceptable initial dilution. Although an initial dilution of 50:’ may nc:
be sufficient to ensure achievement of all water quality criteria, a discnarge
less dilution (landward of’ the 50:1 dilution line) would clearly exceed the specific
water quality criteria for most constituents and, therefore, would not be consiste ’t
with the goals of the EPA Water Quality Criteria.
Protection of Public Health and Marine Life. Tne study area was screened for its
ability to protect public health and marine life using two measures. Tne first
measure was the potential for the area to be consistent with water quality criteria.
which are based on public health ard marine life protection. This was addressec
above by screening out areas which had an initial dilution potential of less thar
50:1. The second measure was the likelihood of a particle discharged a: a soec f:c
location to avoid certain areas, including sensitive aquatic habitat and co’ tac:
recreation locations such as beaches, during a one-half tidal cycle (a roxirate :.
6.2 hours). This one-half tidal cycle represents the incoming portlon of t e
when effluent is being carried toward the shore. The full tidal cycle was not usec
in this analysis as this would have also included the outgoing portion Of a tide
when effluent would be carried offshore. It was conservatively assumed that, dur g
its movement towards a receptor, dispersion of the effluent plume would be minimal
and therefore the concentration of a pollutant after initial dilution would no:
greatly decrease. Tidal excursion (movement) of’ the effluent plume was calculatec
assuming the transport conditions of average tide. Shoreline areas which car te
reached within one half of a tidal cycle (flood tide) were eiim nated fror the a-ca
of potential outfall locations.
E-5
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Avoidance of Sensitive or Unique Resources. Application of the preceding scree i g
criterion also addresses this criterion. However, the goal of this cr1;er or :s to
protect Boston Harbor since effluent entering the harbor would have a long res:de ce
time and could impact the harbor. Boston Harbor (defined here as the area boui e:
by Deer Island, Outer Brewster Island and Point Allerton) and any publicly u c
shoreline including the beaches in Scituate, Hull, Quincy, Boston, Revere, W ”.:irc .
Nahant, Swarnpscott, Marblehead and the harbor islands and the salt marshes of
Cohasset, Winthrop and Revere, were considered the primary sersitive ano u ’xq e
resources for the purpose of screening (Appendix E). Boston Harbor in its ent re:y
was given this designation since it is a major economic, recreation and aesthetic
resource in eastern Massachusetts. Boston Harbor contains a high conce tra:io’i of
commercially and recreationally important marine species including soft shell
clams. In addition, Hingham Bay, which is tributary to the Harbor, is a State
defined area of protection.
The Harbor has historically been, and has the continued potential to be. re2e1vi g
waters for many sources of pollution. Many of these sources, such as marine
commerce, urban run-off and residues from past wastewater practices, are not easily
amenable to pollution control. By preventing direct impacts on the Harbor fro r tne
disposal of Deer Island effluent, maximum flexibility is provided for overall
pollution abatement and waste load allocation in the Harbor. Using the sa e
assumptions concerning effluent particle movement during one half of a tidal cycle
as discussed above, areas where discharge of a hypothetical effluent particle wou!c
either enter the Harbor, or make contact with any of the other sensitive resources
listed above during a one-half tidal cycle were eliminated from further
consideration.
F.2.1.1.2 Application of Criteria.
Initial Dilution Potential. During the summer, the warm upper layer of strat fiec
waters in Boston Harbor/Massachusetts Bay ranges in depth from 30 to 145 feet. ! -
order to achieve an initial dilution of’ at least 50:1, the water depth Iron
discharge ports to the pycnocline must be at least 20 to 25 feet (Figure E.2.a).
Thus, an estimate of the depth required to achieve an initial dilution of 5O: s o-
the order of 70 feet. This assumes the worst-case conditio’i of vertical
F-6
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WATER SURFACE
PYCNOCLINE
FIGURE F.2.a. SCHEMATIC OF DISCHARGE BELOW A PYCNOCLI E
-------
stratification. An analysis of over 600 initial dilution model runs conducted b,
MWRA confirmed that 70 feet is a minimum depth at which an initial dilution of 50:1
can reasonably be expected during stratified cond cions. The 70-foot contour l Ire
which occurs farthest to the east was determined (Figure F.2.b). All reglons west
or landward of’ this line were eliminated from further consideration since these
regions would not provide adequate dilution of the effluent to achieve water qua.1: 3
goals and protect public and aquatic health.
Protection of Public Health and Marine Life. The elimination of areas which are
less than 70 feet in depth addressed the first step in protecting public health and
marine life which is the potential for consistency with water quality criterla. The
second element of this issue, avoidance of sensitive receptors, as addressed by
predicting the fate of effluent particles originating from various locatio’.s during
the incoming portion of a tidal cycle, using the MIT mathematical models TE (Tidal
Embayment Analysis) and ELA (Eulerian-Lagrangian Analysis). TEA is a two-
dimensional, finite element circulation model which simulates tidally drivei
circulation in coastal embayrnents. ELA simulates the transport of a cortamiian:
released in the embayment using results of TEA as input. A more detailed
description of these models and their applications is provided in Appendi:.: f of thIs
Draft SEIS. The models TEA and ELA were used to determine locations closest to
shore where effluent could be released and not reach a receptor or enter Boston
Harbor during the flood portion of a tidal cycle. The impingement of sensitive
receptors due to the predicted effluent transport resulted in the elimination of the
entire Boston Harbor and several coastal areas from further consideration as
potential discharge sites (Figures F.2.c and F.2.d).
Avoidance of Sensitive or Unique Resources. Using the mathematical models TEP and
ELA, along with available data concerning local resources such as local marine
laboratories and State Parks, Figures F.2.c and F.2.d also define the region w :h ’
which effluent would be transported to a unique or sensitive resource during one-
half of a tidal cycle.
F.2.1.1.3 S” ry. The landward boundary of the area of’ potential secondary
effluent discharge locations was determined by combining the 70-foot contour Line
established for predicting the location of initial dilutions or the order of 50:1
with the results of predicted particle transport during one half of a tidal cycle.
F-8
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2.0 9
2.0
STATUTE MILES
1.5 9 _______
NAUTICAL MILES
/
$ALIh
UA.. DE .
E E E
INITIAL DILUTION
OF 50:1
(70’ CONTOUR)
2.5
0
4.5
0
4
0
05
SOLr ’ ’
eDs.O,
6
0
Gra es
3.5
0
3
0
QUINCY
FIGURE F.2.b. BOUNDARY OF MiNIMUM ACCEPTABLE INITIAL DILIT1O\
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Recreational Beaches
Boston Harbor Island State Park
3.5
Graves •
Source: Boston Harbor Islands State Pa’
1986 Master Plan—Mass Derr
MDC, 1984
MWRA, VOL. V, App. L, 1987
• Other Parks
FIGURE F.2.c. FATE OF EFFLUENT PARTICLES DURING THE FLOOD PORTION OF
TIDAL CYCLE AND BEACHES, SHORELINE, PARKS, AND iSLAND PARKS
NA.JTICAL M .ES
STATUTE MILES
‘- --- -I
PROTECTION FROM
EFFLUENT DURING
FLOOD TIDE
5
.
4.5
4
S
6
.
3
LEGEND
COHASSET
-------
• j Saltrnarsh
Significant Identified areas of
i: • Submerged Vegetation
.‘ ‘.‘/ .‘/ ‘/1 reas Oi ritical
Environmental Concern
___________ South Essex Ocean Sanctuary
(Shellfish Beds Sho sn On Figure L)3.
(Bathing BeacIie sho npn hg irc l).3.d.
• Marine Research Facilities
FIGURE F.2.d. FATE OF EFFLUENT PARTICLES DURING THE FLOW PORTION OF A
TIDAL CYCLE AND SENSITIVE HARBOR RESOURCES
NAUTICA. I (SLES
0
S7ATUTE MILES
- - --1’
/
4.5
.
15
.
4
6
.
3.5
.
LEGEND Sources: MWRA Vol. V. APP.L, 1987
BARR. 1987
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Figure F.2.e presents this landward boundary along with potential discharge Sites P
througn 5 (MWRA, STFP V 1987) and Site 6 (Nahant SWIM, 1987). This bomdary
represents the northern, western and southern limits of the area n Massar se::s
Bay which contains potentially suitable secondary effluent discharge locat or.s.
This first screening step eliminated MI4RA’s Sites PR, 1 and 3 from fur: e
consideration.
F.2.1.2 Second Secondary Effluent Site Screening Step: Eastern Boundary
The objective of the second secondary effluent site screening step was to defir e the
eastern or offshore boundary of the area of poteitially suitable discharge
locations. Once the eastern boundary was established, it could be used th ti-c
previously determined landward boundary to define the entire area contain1r
potential secondary effluent discharge locations. Conditions along a traisect
extending seaward, represented by Sites 2, 14, 5 and 6, were compared and contrasted
to determine the eastern boundary of the study area (Table F.2.a). Sites 2, 14 ano 5
were analyzed by M1.4RA (MWRA, STEP V,A 1987). Site 6 was proposed by Nahant S I’
(1987). Analyses for Site 6 were conducted in this SEIS using the actual aeDth at
and distance from Deer Island to Site 6, along with the farthest offshore cjrrert
and density data available (Site 5). Sites 2, LI, 5 and 6 represent a wide range of’
potentially acceptable conditions and are locatec at sufficient dist.aice fro ’ ore
another that differences can be distinguished.
F.2.1.2.1 Eastern Boundary Screening Criteria. No outstanding feature or aorupt
change dictates where the eastern boundary of the study area should be located. The
water depths gradually increase towards the east as do predicted ..ater q..aii:)
conditions, travel time to receptors and cost. The second step of’ seconaar
effluent site screening compared nearfield dilution, farfield background buliduD,
achievement of EPA Water Quality Criteria and length of outfall between landward a-
offshore sites to define where the eastern boundary of the study area should be set.
Nearfield Dilution. The computer model IJLINE was used to calculate i -i t:ai
dilutions at the edge of the mixing zone and the trapped height of the piu-e fc ’
Sites 2, 14, and 5 by t1WRA (t4WRA STFP V,A, 1987) and 6 for this Draft SEIS (ADDend1. .
A). Input parameters to this model included densities of seawater and effiuet.
F-12
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06
2.0
: L’
O 8a N
l E’C
M!/
C ASSE
STATUTE MILES
NAUTICAL MILES
FIGURE F.2.e. LANDWARD BOUNDARY OF SECONDARY EFFLUENT DISCHARGE
PR
SITE 1
SITE 2
SITE 2.5
SITE 3
SITE 3.5
SITE 4
SITE4.5
SITE 5
SITE 6
DISTANCE IN STATUTE MILES TO:
DEER EAST POINT
ISLAND POINT ALLERTON
0.1 5.2 2.3
3.2 4.0 4.3
4.0 2.4 5.2
4.8 2.5 5.5
5.6 6.5 2.6
7.0 5.9 4.9
6.6 3.5 6.1
8.0 5.4 7.0
9.4 6.0 8.1
11.5 9.0 9.0
SALEM
/
/
s . A,. PS:C
E WERE
EAST POINT
LAN DWAR D
BOUNDARY
: C E SE
i’Z /
H f EAST
( e s O
PR
2.5 4
0 0
4.5
0
5
0
0
3.5
0
3
. ‘
C -
2.0
9 1 5
IN RELATION TO ALL DISCHARGE SITE OPTIONS
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TABLE F.2.a. SUMMARY OF DIFFUSER CHARACTERISTICS AND COSTS
Average
Total
Tunnel
Total
Project
Cos:
Depth of
Tunnel
Inside
Construction
Müiion)
Site
Diffuser
Length
Diameter
Time
(feet)
(feet)
(feet)
(months)
2
75
28,000
22
147
276
38;
14
90
143,000
214
51
468
5
100
514,000
25
56
532
6
150
67,000
17
67
* Assumes construction and operation of a pump station
Source: Modified from MWRA, STFP V, 1987.
port discharge, current velocity, depth of discharge, diffuser size and d ffuse
alignment. ULINE is further described in Appendix A of this Draft SEIS.
The nearfield dilution criterion focuses on predicted initial dilution in the
immediate vicinity of the various screening locations. The average exoected initial
dilution and the 10 percentile initial dilution (that dilution which wi1 be
exceeded 90 percent of the time) for each screening site was examined to determine
if there is an abrupt increase or decrease in the rate of improverne’t from one s:te
to another located farther east.
Farfield Modeling of Background Buildup. Farfield mathematical modeliig was
conducted for Sites 2, 14 and 5 (MWRA STFP V,A, 1987), usirg the MIT rnathenatica
models TEA and ELA. Site 6 was similarly modeled for this analysis. These models
were used to determine the overall circulation patterns of the Bostor
Harbor/Massachusetts Bay system and to predict tr.e ultimate fate and transport of
contaminants which either exist in the receiving water or will be discharged to the
site from the Deer Island wastewater treatment plant. Assuming average flow at the
Deer Island wastewater treatment plant, farfield modeling was used to predict the
background buildup concentration of a contaminant for each site. The dilutions
calculated from the background buildup concentrations were exar ined fo an aDruD:
change.
Achievement of U.S. EPA Water Quality Criteria. This criterion focuses or. .r e:he’
toxic pollutant concentrations conform with U.S. EPA Water Quality Criteria a: :ne
F-1 1 4
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edge of the mixing zone. Each predicted pollutant concentration was compared to the
four types of EPA Water Quality Criteria: criteria maxirruin concentration (CMC);
criteria continuous concentration (CCC); human health-toxic; and human health
carcinogenic. The Clean Water Act requires U.S. EPA to publish and periodically
update ambient Water Quality Criteria. These criteria provide a useful guide for
evaluating whether toxic priority pollutants are present in seawater in
concentrations that adversely affect biota and human health (145 Fed. Reg. 79318,
November 28, 1980). Water Quality Criteria are based on available scientific da:a
on the effects of the pollutants on public health and welfare, aquatic life, and
recreation. They establish numerical values which indicate the concentrations of
pollutants in water which will generally ensure water quality adequate to support
the pertinent water use. The criteria represent a reasonable estimate of the
pollutant concentrations that generally will provide adequate protection to health
and the environment. Water Quality Criteria are available for only a partial list
of harmful substances and, therefore, identify the potential for toxic impact to a
limited degree. These criteria are useful in establishing regulatory requirements,
however, they are not rules and do not have regulatory impact (U.S. EPA, 1986).
The concentration of a pollutant at the edge of the mixing zone is a result of the
combination of the pollutant’s ambient concentration, Deer Island effluert
concentration, background buildup concentratior’ and concentrations fror other
sources such as other local wastewater treatment plaits. Concentratiofls of
pollutants at the edge of the mixing zone of Sites 2, Lj and 5 were calculatec by
MWRA (MWRA, STEP V,A, 1987). Similar calculations were conducted for Site £ in
preparation of this Draft SEIS. Certain pollutants (aldrin, arsenic, 14,14’-DDT and
PCB’s) will not achieve all Water Quality Criteria in any region of the stuc area
due to their high concentrations in either the effluent or the receiving water.
Assessment of water quality maintenance during screening was, therefore, used to
assess relative differences in water quality from one location to another. This
criterion was used to determine where abrupt changes in water quality are
predicted. The information obtained by applying this criterion was used i-
establishing an eastern boundary of the area of potential discharge locations.
Length of Outfall. Various outfall lengths were examined to assess differing cos:.
construction duration and technology requirements for the poten:1a diffuser
F-15
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locations. This criterion helps to assess the relative difficulty of implementation
of a diffuser at each site. The outfall length(s) which would pose an increased
level of difficulty relative to other lengths were identified.
F.2.1.2.2 Application of Criteria
Nearfield Dilution. Both average and 10 percentile initial dilutions increase with
distance offshore (Figure F.2.f). The rate of increase in initial dilution is
slightly greater between Sites 14 and 6 than it is between Sites 2 and L I. Thus, ir
terms of both average and 10 percentile initial dilution, to get a maximum increase
in the initial dilution per mile of outfall, the -eastern boundary should be beyo
Site i4
Improvements in initial dilution predicted at Site 6 may also be obtained at Site 5
due to three conservative assumptions made by MWRA in predicting dilution at
Site 5. First, comparison of recent laboratory measurements by the developers of
ULINE with ULINE results indicate that actual initial dilutions may be on average
60% greater than those predicted by the model. Second, to analyze achievemeit of
the EPA CMC Water Quality Criteria, KWRA estimated initial dilution corresponding to
any 214 hours over three years as opposed to the criteria basis of 214 continuous
hours over three years. This was done using the current speeds during slack tice
which do not occur consecutively over a 214-hour period in three years. Third, M’ P
input a diffuser length of 1,500 meters to ULINE for Site 5. Initial dilutio’ s
predicted during MWRA’s analysis were lower than those predicted when a diffuser
length of 2,000 meters, the proposed diffuser length, was input to the model. The
first two conservative assumptions made by MWRA would also produce higher init a.
dilutions at Site 6.
Faruield Modeling of Background Buildup. Based on their farfield modeling results.
MWRA determined estimates of unstratified and stratified background buildup
concentrations for Sites 2, LI and 5 (Table F.2.b). Background buildup is used jr
assessing impacts of’ effluent discharge for site screening since it is relatively
simple to obtain. Actual farfield impacts of effluent discharge would be related to
pollutant concentrations from the background buildup, ambient seawater, and other
sources as well as initial dilution. Background buildup concentrations can be
F—16
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4
4
DISTANCE (MILES)
I I(t JR K I’.2.i. A VKII A(E A NI) TKN PI;RCKNTI I.E I NW Al. 1)1 II ITIONS AT SITES 2. 4. 5 A NI) 6
0
A
LEGEND
AVERAGE DILUTION
10% DILUTION
260
240
220
200
140
120
100
80
60
z
0
I-
-J
0
20
0
0
SITE
2
2
SITE
SITE
5
6 8
SITE
6
10
12
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TABLE F.2.b. DILUTIONS OF BACKGROUND CONCENTRATIONS OF CONTAMINANTS
Site
20
Strat
days
ified Cond
Half Life
60 days
itions
Conservative
20
Unstra
days
tified Conditions
Half Life
60 days Conservative
2
614
143
29
119
79 53
14
53
38
27
190
136 95
5
108
81
65
317
238 190
6
196
1146
118
396
297 238
converted to dilutions using the average discharge concentration corresponding to
the assumed loading. Background dilutions for Site 6 were calculated in a s rgle
run of ELA for a pollutant with a 20-day half life for unstratified conditicr.s,
assuming a north-south tilt. Increase in dilution of approximately 25 percent t. .as
found at Site 6 compared to Site 5. This percentage increase was assumed to also
apply to compounds with 60-day half lives and conservative compounds.
corresponding increase of background buildup dilution of 80 percent was obtained for
stratified conditions. This percentage increase for stratified cor.dit1or s was also
applied to compounds with 60-day half lives and conservative compounas. This was
sufficient for a screening level of detail as a more detailed analysis would have
required modifications of the finite element computational grid which wO ,.jid ha..e
gone beyond a screening analysis effort.
Dilutions of MWRA background build-up of contaminants which have half lives of
60 days are presented in Figure F.2.g. Half life is the time required for one half
of a quantity of a substance to be eliminated from the water column. This is
independent of any transport of the substance which coulc occur. These vaiLes
represent the mid-range dilutions of background contaminants for each site and a ’e
representative of the trends with contaminants which have either 20-day half l1\es
or are conservative compounds.
During long—term average conditions, compounds with a 60-day half life ha. .
dilutions of’ 79 at Site 2 and 136 at Site 14. This represents an ircrease
dilution of 28 percent per mile. In contrast, since the cilution at Site 5 is 235.
the increase in dilution between Sites 14 and 5 is 27 percent per n-ile. At Site 6,
the dilution is 297 and the increase in dilution from Site 5 to Site 6 is 12 oerce t
F-lB
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LEGEND
O STRATIFIED
A UNSTRATIFIED
SITE
2
4
I I I I I
I I I
I I
2 4 6 8 10 12
DISTANCE (MILES)
I•’I(;I;I{.I . 1’.2.g. I)lI,IJ’I’IONS 01’ BACKCROIJNI) B(I1I,I)LII’ CON’I’AMINANI’S VII’II (0-I)AY IIAIF I,tVI S
z
0
I-
-j
0
400 —
350-
300-
250 -
200 -
150—
100 -
50 -
0-
0
SITE SITE SITE
5
6
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per mile. Thus, the sharpest increase in dilution is between Sites 14 and 5 during
average conditions. During conditions of vertical stratification, a corn ound at
Site 2 with a 60-day half life has a dilution of 143 while at Site Lz, the dilution is
38. This represents a decrease in dilution of 14 percent per mile from Site 2 to
Site 14. At Site 5, the dilution during stratification is 81 which represents an
increase in dilution of 140 percent per mile. There is a dilution of 1146 at Site 6
during stratified conditions and an increase in dilution of 38 percent per mile
between Site 5 and Site 6. During stratified conditions, the highest increase in
dilution is between Sites 5 and 6. In general, the largest increase in dilution of
background contaminants begins between Sites 14 and 5.
Achievement of U.S. EPA Water Quality Criteria. KWRA calculated concentrations of
pollutants at the edge of the mixing zone at Sites 2, 14 and 5 using the results of
computer modeling, measured ambient concentrations of pollutants and predicted
secondary effluent concentrations of pollutants (MWRA, STFP V,A, 1987). As
described in Appendix A of this Draft SEIS, these concentrations are estimates and
are not exact predictions. Predicted concentrations of t4WRA’s effluent were oased
on average removal rates at average pollutant loads. Simi1.ar analyses were
conducted for Site 6 in preparation of the Draft SEIS. The predicted concentra:ior.s
of pollutants at the edge of the mixing zone were compared to the sixty U.S.
Water Quality Criteria (Table F.2.c). According to MWRP, seven exceedances of the
U.S. EPA Water Quality Criteria are expected as a result of discharging secondary
effluent at Site 2. There are six predicted exceedances of water quality criteria
at Site 14 and five expected exceedances at Sites 5 and 6. Psnbient concentrations
of arsenic and PCB’s cause three of the exceedances at each of the sites. (Tn:s is
discussed in Appendix A of this Draft SEIS). Improvement in achieverrent of U.S.
Water Quality Criteria goals during discharge of secondary effluent would occur at
Site 14 and Site 5. East of Site 5, conformance with water quality criteria would
remain constant for over 2 miles. Thus, in terms of water quality crite”ia
achievement, there are some exceedances at all sites. Sites 5 and 6 are den:ical
in conformance with U.S. EPA Water Quality Criteria goals; Site 6 does not proviae
any significant benefit over Site 5 in this respect.
F -20
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TABLE F.2.c SUMMARY OF SECONDARY EFFLUENT CONSTITUENTS WHICH ARE
EXPECTED TO EXCEED EPA WATER QUALITY CRITERIA CONCENTRATIONS AT THE
EDGE OF THE MIXING ZONE
Criterion/Constituent
Si
te
2
14
5
6
ccc 1)
Mercury
X
X
Polychiorinated
(2)
Biphenyls (PCBs)
X
X
X
X
Carcinogenicity 3
Aldrin
X
X
X
X
1 4, 1 4’-DDT
x
x
x
>:
Heptachior
X
Arsenic
X
X
X
X
Polychiorinated
Biphenyls (PCBs)
X
X
X
X
Total
7
6
5
5
(Source: modified from KWRA, STEP V,A, 1987.)
(1) Criterion continuous concentration (CCC) four-day average concertration not
to be exceeded more than once in three years.
(2) Exceedances due to ambient concen:rat1or s. More recent amblent data indicate
PCB exceedances may not occur at all sites, see detailed evaijation in
Chapter 5.
(3) Carcinogenicity 10° risk of cancer from lifetime consumption of fish
continually exposed to predicted concentration at the edge of mixing zone.
(LI) Ambient concentration exceecs criteria. At Site 2, MWRA contribution excee s
criteria.
F-21
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Length of Outfall. Based on the proposed site plan of the Deer Island wastewater
treatment plant, effluent can be conveyed via gravity flow in a large dianeter
outfall or by effluent pumping in a smaller diameter outfall for a distaflce c’
9 +1 miles. However, past 9 + 1 miles from Deer Island, effluent flow would have to
be conveyed by effluent pumping.
The cost per foot of a gravity flow system is relatively expensive and increases
with length. The cost increases with tunnel length as a result of less productive
work days due to longer travel time to the construction site. Initial cost of a
pumped flow system is high due to the capital cost and operation and maintenance
costs associated with a pump station. The high costs of pumping are offset by the
cost of the smaller diameter outfall which is significantly less expensive than the
larger gravity flow outfall. The gravity flow system is more cost-effective for
distances less than 9 + 1 miles and the pumped flow system is more cost-effective
for distances greater than 9 .i. 1 miles (Figure F.2.h). Therefore, a gravity flow
system is preferred for sites which are within approximately 9 miles of Deer Island
while pumped flow is preferred for sites located more than 9 miles from Deer
Island. While there is no distance at which an abrupt increase in cost occurs, cost
construction costs at Site 6 would be $60 to $70 million higher than at Site 5.
However, it is difficult to establish the boundaries of the area of potentiaLy
suitable discharge sites using only an economic basis.
F.2.1.2.3 Siimm ry. The rate of initial dilution increase is greater beyond Site LI
than between Sites 2 and LI. Under stratified and average conditions, predicted
background buildup of contaminants remains fairly constant and relatively high fror
Site 2 to L I. Seaward of Site LI, there is a relatively large decrease in predicted
background buildup of contaminants. Based on these criteria, the eastern bouncary
should be east of Site 14• For the discharge of secondary effluent, predicted EPA
Water Quality Criteria exceedances are reduced by one from Site 2 to Site LI and
one from Site 14 to Site 5. No reduction in exceedances is predicted from Site 5 :c
Site 6.
The outfall cost increases linearly with distance offshore. While there s o
strict economic basis for establishing an eastern boundary, it was determined tnat
an outfall to Site 6 would cost $614 million more than an outfall to Site 5. An
F -22
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LEGEND
• COST OF PUMPED FLOW
o COST OF GRAVITY FLOW
LOWEST COST SYSTEM
SITE 2
4
I I
6
DISTANCE (MILES)
540 -
520 -
500 -
480 -
460 -
440 -
420 -
400 -
380 -
360 —
340 -
320 -
300 -
280 -
260 -
U
U)
z
0
-J
-J
I-
(I,
0
0
I
I —
a:
0
I—
z
LU
(I,
LU
a:
0
N
0
2
SITE
4
SITE
5
8
SITE
6
10
12
I I{ E I’.2.h. (:osr OF O(JI’IA 1.1. SYS’I’KM ft ITER N A’I’I ’ ES
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outfall to Site 6 would require a pump station which could be subject to operatlor.a!
difficulties such as breaking down. All sites would require tunnelled or excavated
material disposal. The volume of material from constructing an outfall :0 Site 6
would be greater than volumes of material from the other sites.
Based on the above, there is sufficient justification for extending the eastern
boundary past Site 4 (Table F.2.d). The only justification for extending the
boundary past Site 5 is to increase initial and farfield dilutions. The number of
water quality criteria exceedances predicted for Sites 5 and 6 are equal. Thus,
there is no practical difference in public health risk between these sites. Even
east of Site 6 there would likely be predicted exceedances of the U.S. EPA Water
Quality Criteria. Predicted exceedances and their impacts at Sites 5 and 6 will
have to be addressed by a method other than increasing the outfall length, such as
source control or pretreatment, and therefore, Site 6 would provide no advartage
over Site 5. Pretreatment or source control, rather than increased d lut.ion, is a
more preferable means of controlling pollution. Based on both the screer.ing
analysis of this Draft SEIS and MWRA’s analysis, there are few predicted imDacts at
Site 5 and none which would be eliminated at a more offshore SitC. Therefore the
eastern boundary encompasses Site 5 but excludes Site 6 (Figure E.2.i). The area
defined by the landward and eastern boundaries is judged to be adequate to pro vice a
reasonable range of discharge location alternatives.
TABLE F.2.d SITE SCREENING CRITERIA BREAKPOINT LOCATIONS
Screening
Criterion
SITE
6
2
5
Nearfield Dilution
X
Farfield Dilution!
Background Buildup
X
Achievement of
Water Quality Citeria
(Secondary Effluent)
x
Cost of Gravity Flow
Cost of Pumped Flow
X
* Designates the site at which an abrupt i
mprovemen
t is predic
tea.
F_2L
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EASTERN
BOUNDARY
‘
5
ci 6
I °
/
/
2.0
STATUTE MILES
9 1.5
NAUTICAL MILES
FIGURE F.2.i. AREA OF POTENTIALLY ACCEPTABLE SECONDARY
EFFLUENT DISCHARGE LOCATIONS
DISTANCE IN STATUTE MILES TO:
DEER EAST POINT
ISLAND POINT ALLERTON
BE
PR
SITE I
SITE 2
SITE 2.5
SITE 3
SITE 3.5
SITE 4
SITE4.5
SITE 5
SITE 6
0.1
3.2
4.0
4.8
5.6
7.0
6.6
8.0
9.4
11.5
5.2 2.3
4.0 4.3
2.4 5.2
2.5 5.5
6.5 2.6
5.9 4.9
3.5 6.1
5.4 7.0
6.0 8.1
9.0 9.0
SALEM
ME ROSE
SA O_S
LAN DWARD
BOUNDARY
2.5
0
4.5
0
4
0
1
0
3.5
Grsvss
s:
3
, ,
/
/
MO
OVIRCY
O d C hr
2.0
1 5
CO. .ASSE
Co assa’
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F.2.1.3 Final Screening Step: Alternative Discharge Locations
The objective of the final screening step was to identify locations, within the area
of potentially acceptable discharge locations, for detailed evaluation and
comparison. Two issues were important in selecting alternative locations: to
ensure that the range of physical oceanographic, geologic, biologic and water
quality conditions within the area were represented by the alternative locations and
to establish alternative discharge locations which have sigrif’icar t enoug
differences to permit meaningful comparisons. Since analytical tools available to
compare impacts require relatively large differences in existing conditions to
elucidate significantly different results, alternative discharge sites had to be
well spaced on the gradient of existing conditions to make the cornpariso s
productive.
In selecting alternative locations, sites which were investigated by MWRA (MWR ,
STFP V,A, 1987) and which passed the first and second level screening were
reviewed. If a discharge location met the two objectives discussed above, it was
selected for detailed evaluation.
F.2.1.3.1 Site Designation. Sites investigated by M14RA within the area of
potentially suitable outfall locations include Sites 2, 2.5, 3.5, 14, 14.5 and 5.
Sites 2.5, 3.5 arid 14.5 are intermediate sites which were investigated by MWR ir
less detail than the other sites. The extremes in range of conditions within the
area are represented at Sites 2 and 5. Therefore, these two sites were chosen for
detailed evaluation. Based on MWRA’s analysis (M 4RA STFP, V,A, 1987), there is o
large change in predicted dilution or water quality conditions between Sites 2 a:
2.5. Since expected differences between these two stations are less than the
sensitivity of the analytical tools, Site 2.5 was eliminated. Site 14 represents a
distinct change in depth, dilution and potentially other characteristics from oot’
Sites 2 and 5. Therefore, it was chosen for detailed evaluation to quantify these
differences and to allow for meaningful comparisons. Sites 3.5 and 14.5 fall withi .
the range of oceanographics conditions represented by Sites 2, 14 and 5. Since they
provide no unique characteristics such as increased depth, distance from a resource,
current regime or reduced construction costs, and their similarity with Sites 14 ar.d
5 would restrict meaningful comparisons, they were not evaluated in detail. Based
F-26
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on the criteria of this screening process, the sites chosen for detailed evaluatloi
were Sites 2, 14 and 5 (Figure F.2.j).
F.2.1. 1 I Interim Discharge Screening
A necessary step in implementing the required Deer Island secondary wastewater
treatment plant is to discharge primary effluent during the five-year construction
period. The objective of this screening was to determine the potentially acceptable
locations for the five-year interim discharge of primary effluent. Sites considered
were the existing Deer Island discharge site in President Roads (Site PR) and those
sites which were selected for detailed analysis in this Draft SEIS (Sites 2, 14
and 5). Although Site 6 would have greater dilution, it was not included in the
screening of potential primary discharge locations since it did not survive tie
secondary effluent screening due to its lack of long-term benefits over Site 5.
F.2.1.IL,1 Screening Criteria. The criteria for this screening were selected to
determine if the five year interim discharge of primary effluent, from 19914 to 199.
should occur at the existing discharge site (PR) or if it should be moved into
Massachusetts Bay, where potentially suitable secondary effluent discharge sites
have been identified.
Compliance with Massachusetts Surface Water Quality Standards, achievement of U.S.
EPA Water Quality Criteria, shoreline impacts of pollutants and cumulative effects
of discharging were used as criteria during the screening of primary efflue c
discharge sites.
Achievement of U.S. EPA Water Quality Criteria. As described earlier, this
screening criterion assesses whether a toxic pollutant concentration achieves U.S.
EPA Water Quality Criteria goals at the edge of the mixing zone. These criterla are
useful in establishing regulatory requirements but do not have regulatory impact.
Results of this analysis were used to assess relative differences in water quality
between Site PR and the potentially acceptable secondary effluent discharze
locations (Sites 2, 14 and 5).
F-27
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2.0 0 2.0
I —
STATUTE MILES
1.5 0 1.5
I — ‘
NAUTICAL MILES
E ERE
C-E.$E -
/‘ __y

‘ —8a
‘
_____ ,:
$A i.I
/ /
s Au s:c’
L
//
• $A 3 5
i) /2
.E E EAST POINT
2
0
Is
C —
(l lV
So.cu L
C T
/ C auoci
‘$ s.’ L_ ‘II
- oso-
l E • 2 ::VI -
POtNT ALLERTON
P ocij •_/ Si,
• Ir
(
ISI$

ouI cY N . .\ 0 5 .
GAV
PRESIDENT ROADS
5
4 0
0
/,
Trss Graves
: — ss -
FIGURE F.2.j. ALTERNATIVE DISCHARGE LOCATI ON S
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Compliance with Massachusetts Surface Water Quality Standard. Unlike the U.S. E?
Water Quality Criteria, compliance with the Massachusetts Surface Water Quality
Standards is required by law. These standards regulate discharges of pollutants to
surface waters and insure that designated uses of surface water will be achieved ard
maintained by improvement in maintenance of Water Quality Conditions.
Although there are four conventional pollutant parameters for which numerical state
water quality standards exist, dissolved oxygen (DO) is the critical standard for
comparing primary discharge locations. DO must be at least 85 percent of saturation
at temperatures above 77°F and at least 6.0 mg/l at temperatures of 77°F and below.
Shoreline Impacts of Pollutants. Impacts of discharging effluent at Sites PR, 2,
and 5 were predicted for this screening step using the results of MWRA’s analysis
(MWRA STFP V,A, 1987). Percentages of effluent concentrations which would contact
the shorelines of Winthrop, Hull and Nahant during an extreme event were preaicted
using assumptions of unstratified conditions, high current velocities and 60—day
half life background concentrations for average conditions. Assumptions used in
establishing the extreme event included: an average contarnlnant loading plus one
standard deviation, the plume had to rise to the surface to be present in the upper
water column, transport velocity of the diluted effluent is 0.013 tlmes the wind
speed, surface currents are 15 degrees to the right of the instantaneous Wind
velocity, subsequent dilution is due to lateral spreading only and no natural deca ,
occurs during subsequent dilution. This criterion is used to predict shorel re
exceecances of U.S. EPA Water Quality Criteria, using M1.4RA’s analysis ( 4WF ,
STFP V,A, 1987).
Cumulative Water Quality Impacts. The interaction of an M RA discharge with otrer
pollution sources was used to evaluate alternative primary treatment d1sc arg.9
areas.
F.2.1.k.2 Application of Criteria
Achievement of’ U.S. EPA Water Quality Criteria. MWRA calculated conce’ trat1crs of
toxic pollutants at the edge of the mixing zone for Sites PR. 2, 14 ar.d 5 LS:r g
results of computer modeling, measured ambient pollutant concentrations anc
F-29
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predicted primary effluent pollutant concentrations. These pollutant conce itratiors
were compared to the U.S. EPA Water Quality Criteria. Discharge of primary effluent
at Site PR is predicted to cause the exceedances of thirteen of the sixty Water
Quality Criteria (Table F.2.e). At Sites 2 and 14, twelve Water Quality Criteria are
expected to be exceeded during discharge of primary effluent. Eleven Water Qua1 ty
Criteria would be exceeded at Site 5. Thus, in terms of water quality achiever’ert.
Site 5 provides the most benefit while Site PR provides the least.
Compliance with Massachusetts Surface Water Quality Standards. MWRA assessec the
predicted compliance of primary effluent discharges at Sites PR, 2, LI and 5 with the
four conventional pollutant parameters for which there are numerical Massachusetts
Surface Water Quality Standards (M14RA, STFP V,A, 1987). M’WR?’s analyses
underestimated adverse impacts on dissolved oxygen (DO) concentratIons due to
effluent discharge at the various sites. Predicted DO concentrations at the
alternative discharge locations were refined and are presented in Appendix A of this
Draft SEIS. The relative differences between the sites remains the same; therefore.
results of MWRA’s analysis is used in this screening process to determine relative
differences in DO concentrations between Sites PR, 2, 14 and 5.
Results of MWRA’s analysis indicate that with the exception of dissolved oxyge-
concentration, the Massachusetts Surface Water Quality Standards would be me: at
Sites PR, 2, 14 and 5 during the discharge of primary effluent. The dissolved o: yge1
standard was predicted to be violated “very often” at Site PR, “often” at Site 2.
“occasionally” at Site L I and “seldom or never” at Site 5 during primary effluent
discharge.
Shoreline Impacts of Pollutants. MWRA (MWRA, STFP V,A, 1987) predicted distarces.
excursion times and dilution subsequent to initial dilution during extre-re
conditions at Sites PR, 2, 14 and 5. (Table F.2.f). During extreme cond t ons.
effluent discharged at Site PR could reach the Winthrop and Hull shorelines within
6.6 and 5.1 hours, respectively, or approximately one half of a tidal cyce
(6.2 hours). Release of effluent at Site 2 would have similar’ impacts on Naba”:
since excursion time during extreme conditions would be 6.6 hours. Excursion ti i’es
from Site 14 range from 9.14 hours to reach Nahant to 19.3 hours to reaci null. From
Site 5, excursion times range from 15.5 hours to Nahant to 27.8 hours to 4inthrcp.
F-3O
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TABLE F.2.e SUMMARY OF PRIMARY EFFLUENT CONSTITUENTS
WHICH ARE EXPECTED TO EXCEED EPA WATER QUALITY CRITERIA
CONCENTRATIONS AT THE EDGE OF THE MIXING ZONE
F-3 1
Criterion/Constituent
Sites
PR
2
5
CMC 1)
Copper
X
X
X
ccc (2)
Heptachior
X
X
X
X
LI,14’..DDT
X
X
X
X
Dieldrin
X
Mercury
Polych1orinated 3
X
X
X
X
X
X
X
X
Biphenyls (PCBs)
Carcinogenicity
Aidrin
X
X
X
X
1i,L ’ _DDT
X
X
X
X
Heptachior
X
X
X
X
Dieldrin
X
X
X
X
Flouren
Arsenic ’ 5
X
X
X
X
X
X
X
X
Polychiorinated
X
X
X
X
Biphenyls (PCBs)
Total
13
12
12
11
(Source: modified from MWRA STFP, \, 1987)
(1) Criterion maximum concentration (CXC) one-hour average concentration not to
be exceeded more than once in three years.
(2) Criterion continuous concentration (CCC) four-day average concentration not
to be exceeded more than once in three years.
(3) Exceedances due to ambient concentrations. More recent ambient data indicate
PCB exceedances may not occur at all sites, see detailed evaluation it-.
Chapter 5.
(14) Carcinogenicity 1O ’ risk of cancer from lifetime consuirption of fist-.
continually exposed to predicted concentration at the edge of mixing zone.
(5) Arnbien: concentration exceeds criteria. At Site 2, MWRA contrioution exceeds
criteria.
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TABLE F.2.f PREDICTIONS OF DISTANCES, EXCURSION TIMES AND
SUBSEQUENT DILUTIONS AT SHORELiNE AREAS FOR EXTREME EVENTS
Dilution Subsequent to
Distance in km (miles) to Excursion Time (hrs) to Initial Dilution
Site Nahant Winthrop Hu!l Nahant Winthrop Hull Nahant Winthrop 9u11
PR 9.2 3.8 14.5 19.7 6.6 5.1 3.2 2.0 1.8
(5.7) (2.14) (2.8)
2 3.8 6.14 8.3 6.6 11.2 16.6 1.9 2.5 3.0
(2.11) (14.0) (5.2)
14 5.7 10.3 9.5 9. 14 17.1 19.3 2.3 3.0 3.2
(3.5) (6.14) (5.9)
5 9.5 114.8 13.0 15.5 27.8 27.6 2.9 3.7 3.7
(5.9) (9.2) (8.1)
Excursion times to Winthrop and Hull increase with distance from the shore. t
Nahant, excursion time decreases from Site PR to Site 2 and then increases witri
distance from shore. Effluent released at Site PR would dilute 2.0 or less tur s
after initial dilution prior to reachirg Wlnthrop or Hull.
Discharging at Site 2, rather than Site PR, would provide a decrease in
concentration of effluent at the shoreline ranging from 38 percent at Nahant to
78 percent at Hull (Table F.2.g). For a Site L I discharge. shoreline concentratio
of effluent decreases, as compared to discharging at Site PR, range from 73 perce-t
at Nahant to 89 percent at Hull. Similarly, decreases in shoreline concentratiors
of’ effluent from Site PR to Site 5 range from 86 percent at Nahant to 9L1 pe’cent at
Hull. The shoreline impacts at Winthrop, Nahant and Hull as well as the nar:cr
islands and Boston would be much greater from a Site PR discharge than from either
Sites 2, 14, or 5.
Distance from the discharge to shore, as a means of predicting impacts of the
discharge, can be misleading. For instance, the distance between Nahant and Site P
is 9.2 kin while distance between Nahant . and Site 11 is 5.7 km. However, :F-
percentage of effluent which would contact the Nahant shoreline is much higher for
Site PR (1.52 percent) than for Site 14 (OJfl percent). During surr.mer stratified
F-32
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TABLE F.2.g PREDICTED PERCENTAGES OF EFFLUENT CONCENTRATION
AT THE WINTHROP, HULL AND NAHANT SHORELINES DURING EXTREME EVENTS
Discharge
Site
Percentage of Effluent at Shorel re
Winthrop
Hull
Nahar.t
PR
2.143
2.70
1.52
2
0.71
0.59
0.914
Lj
0.32
0.30
0.141
5
0.16
0.16
0.21
conditions, the effluent plume from Sites 2, II and 5 would remain subn erged aid
therefore is not likely to affect shorelines, while at Site PR, where there is
greater mixing, the plume would rise to the surface and could impact the shoreline.
Cumulative Impacts. Broad Sound/Massachusetts Bay is the receiving water for t ie
waste of several coastal communities. Impacts due to the discharges fror these
communities are minimal, however, since they represert a relatively small ano n: of
waste discharged to a large volume of receiving water. The assin’ilat ve capaclty of
the Broad Sound/Massachusetts Bay System is large, therefore this area is presen:ly
unstressed.
In contrast, Boston Harbor is the receiving water for 11 billion gallons of cornbiie
sewer overflow (CSO) and stormwater runoff annually. Boston Harbor receives
discharge from the Mystic and Charles Rivers and a highly urbanized dralnage
basin. It also receives the effluent discharge frorr the ex st1ng Deer Island plant
and the sludge discharge from Deer and Nut Island plants. These treatment plait
discharges represent a combined load of 107 metric tonnes per day of carbonaceous
biochemical oxygen demand (CBOD) and 23 metric tonnes per day of nm.trogeio. s
biochemical oxygen demand (NBOD) into President Roads (MWRA, STFP V,A, 1987).
The accumulation of these pollution sources has produced a h ghiy stressed Bos:on
Harbor marine ecosystem (MDC, 19814). There are significant accuim lations of bo::o-.
sediments with high concentrations of toxic compounds and oxygen derranc. There are
also very dense communities of pollution tolerant organisms and near azoic areas.
I- -1
r —.
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There are violations of water quality standards for DO and the aesthetics are
sign ificantly degraded.
Discharge of primary effluent to Presidents Roads from the new Deer Island fac i:ty
would include wastewater currently being treated by both the Nut and Deer Island
WWTPs and would result in a load of about 250 metric tonnes per day of CBOD and
150 metric tonnes per day of’ NBOD (MWRA, STEP III, 1987). This represents an
increase of over 250% above existing loadings to President Roads. Such ar increase
would produce aesthetic, marine ecosystem and water quality conditions even worse
than the already highly degraded conditions. Future BOD loadings would be higher
than existing BOD loadings since the discharge would include effluent which is
currently discharged by both Nut and Deer Island WWTPs. Also, the capacity of the
upgraded Deer Island WWTP would be larger than the existing combined capacit es of
the Nut and Deer Island W1 TPs.
F.2.1. 1 i.3 Summary.
Based on application of the above criteria, it is clear that discharge of primary
effluent at President Roads should be discontinued once the new effluent outfall
system is constructed. Discharging primary effluent at Sites 2, 14 or 5 rather than
at Site PR would offer the benefits of increased water quality criteria ac evement
at the edge of the mixing zone, decreased percentages of’ effluent. at the shorelines
of Winthrop, Hull and Nahant, increased compliance with the state dissolved oxygefl
concentration standard and less chance of further stressing the Boston Harbor
ecosystem. Therefore, discharge of primary effluent to President Roads during the
five year interim period was screened from further consideration. Discharge of
primary effluent for the five year interim period is evaluated for Sites 2, 14 and 5
in Appendix A of’ this Draft SEIS.
F.2.2 DESCRIPTION OF DISCHARGE LOCATION ALTERNATIVES FOR DETAILED EVALUATION
Although these locations are called “sites”, they are actually regions wit :’
Massachusetts Bay in which an outfall could be located. These sites do ‘ot
designate specific outfall locations. Sites chosen for further evaluation are
described as follows:
F -314
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• Site 2 is in Broad Sound, located ILO miles northeast of Deer Isla ,
2.14 miles south of Nahant and 5.2 miles north of’ Hull in 75 feet below mear
low water (MLW).
• Site LI is in Broad Sound, approximately 3.6 miles southeast of Nahant,
6.6 miles northeast of Deer Island and 6.1 miles north-northeast of Hull.
It is located at a water depth of 90 feet MLW.
• Site 5 is in Massachusetts Bay. This site is located 6.0 miles east-
southeast of Nahant, 9.1! miles northeast of Deer Island and 8.1 miles
northeast of Hull in 100 feet MLW.
Sites 2, 14 and 5 correspond to sites which were investigated by the M1.4RP ft
preparation of’ the Secondary Wastewater Facilities Plan (M14RA, 1987), ar d are
already known to the public and agencies by these names. Thus, to be co s.stent,
this Draft SEIS refers to these locations by their original names.
F.2.3 CRITERIA FOR DETAILED EVALUATION
The criteria which were used in evaluating the alternatives in this Draft SEIS are
presented below. These criteria were applied in the detailed evaluation of’ sites ifl
Chapter 5. Results of these analyses are compared in Chapter 7.
F.2.3.1 Water Quality
Ability to Meet EPA Aquatic Life Water Quality Criteria. The U.S. EPf Ambient hater
Quality Criteria are established to assure the protection of human health and marine
organisms from aaverse effects due to the presence of certain pollutar ts in aa atic
environments. These criteria are useful for interpreting the more qua! t1ve Mass.
Surface Water Quality Standards for toxicity but are not regulatory standards.
Each alternative discharge site was measured based on its ability to meet E-
Aquatic Life Water Quality Criteria goals as defined in Quality Criteria for Water
(U.S. Environmental Protection Agency, May 1, 1986, EPA 14140/5—86-001). Achieverr.er t
of EPA Public Health Water Quality Criteria is described in Section F.2.3.5.
Conformance With Mass Water Quality Standards. Massachusetts Water Q aL:t.
Standards are used to protect marine biota from harmful effects of conventio-a
F -35
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pollutants from primary and secondary effluent. Alternative discharge locaticrs
were assessed based on the ability of the discharge to comply with Massachusetts
Water Quality Standards. Measurement of this criterion was based on the pcter t a1
number and nature of violations of Massachusetts Water Quality Standards which are
expected to occur at a specific site.
Impacts of’ Pollutants at Shoreline. Percentage of’ effluent pollutant concentrations
at the shoreline were calculated for discharge at each alternative discharge
location. Measurement for this criterion was based on these predicted percentages
at the shoreline.
F.2.3.2 Sediment Quality
Adverse Toxics Accumulation. This criterion assesses the potential impacts or
marine biota due to the accumulation of toxics in sediment. The predicted impact at
each diffuser location was rated based on the number of compounds expected to be
present in the sedimert at toxic concer trations. Specific numerical levels for
individual constituents were assessed from the literature and used to make these
measurements. The procedure is described in Appendix C of this Draft SEIS.
Adverse Effects Due to Sediment Enrichment. Impacts on benchic orgarusms d e to
organic loadings from the discharge were examined. This criterion was measured
using predicted amounts of organic enrichment. A concertration of less than.
0.1 g C/m 2 /day will produce “No Noticeable Effect”. Between 0.1 and 1.5 g C/m 2 /day
will produce “Changed Benthic Communities”. Concentratlons greater tha ’
1.5 g C/m 2 /day will produce “Degraded Benthic Communities”. The de:a 1e
development of these limits are presented in Appendix C of this Draft SEIS.
F.2.3.3 Marine Ecosystems
Adverse Effects Due to Water Column Enrichment. Impacts due to nitrogen enrichi er:
of the water column was assessed using predicted amounts of nitrogen enrichrne z.
Increases in nitrogen concentrations of less than 0.111 mg,l will produce “\
Effect”. Concentrations of 0.111 to 0.5 mg/i nitrogen wi!l procuce stimu1atio’ of
primary production, with no oxygen depletion, resulting in “Changed” conditions. t
F-36
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concentrations of nitrogen greater than 0.5 mg/i, excessive oxygen demand or even
anoxia would occur result in “Degraded” conditions.
Safeguarding Protected Species from Habitat Modifications. The potential for
adverse impacts on habitats of protected species was assessed during application of’
this criterion. The relative impacts predicted between the alternative discharge
sites were measured using relative ratings “Minor”, “Moderate” and “Extensive”.
Avoidance of Sensitive and/or Important Habitat. This criterion measures the
potential for affecting areas which are highly susceptible to impacts of sewage
discharge, including submerged vegetation and shellfish areas. Measurene t of this
potential was based on the relative ratings of “Minor”, “Moderate” and “Exteisive”
between the alternative discharge sites.
F.2.3. 1 1 Harbor Resources
Protection of Offshore Recreation and Aesthetics. This criterion assesses the
potential to protect recreation and aesthetics in the open waters and along the
shorelines of’ Massachusetts Bay and to restore and protect recreation and aesthetics
of’ the open waters and along the shorelines of Boston Harbor. Measurements for this
criterion were conducted using a relative rating of’ “Minor”. “Noderate” or
“Extensive” adverse impacts.
Protection of Cultural and Historical Resources. The potential to protect a eas of
cultural or historical value will be assessed for each alternative discharge
location. Included in this assessment will be potential impacts on archaeology an
historic resources such as shipwrecks. Comparison ratings of “Minor”, “Moderate”
and “Extensive” adverse impacts were assigned to each of the alternative discharge
locations.
Protection of Co ercial Fishing Activities. Potential interference with commercial
fishing activities such as dragging, trawling, gillnetting and lobstering ar
preemption of fishing areas in Massachusetts Bay were examined. Each alternative
discharge site was assignec a relative rating of “Minor”, “Moderate” or “Extensi e”
adverse impacts depending on the impacts predicted compared to the other sites.
F-37
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Protection of Co ercial and Recreational Species. The potential for maintenance of
potentially harvestable stocks of commercial and recreational aquatic species was
examined for each of the alternative discharge locations. Relative measL’re er:s fc ’
each site were made using ratings of “Minor”, “Moderate” and “Extensive”.
Water Traffic. Interference with commercial and recreational marine traffic as a
result of construction at each of the alternative discharge sites was examined.
Water traffic interference is related to the amount of time which marine traffic
would be disturbed during the construction project due to the life span of the
project or the travel time required to get to a specific discharge site.
Measurement for this criterion was made on a relative basis to compare the
alternative sites using “Minor”, “Moderate” and “Extensive” as ratings.
F.2.3.5 Public Health
Ability to Meet EPA Public Health Water Quality Criteria. The ability of discharge
sites to insure the protection of public health will be evaluated. This criterion
involves examining data on existing and projected levels of pathogens and
carcinogens in water, sediment and seafood. Each alternative discharge site was
measured based on its ability to achieve EPA Public Health Wate’ Quality Criteria
goals.
F.2.3.6 Engineering Feasibility
Constructibility. The criterion of constructibility assesses the difficulty and
risk associated with locating the diffuser at each of the alternative discharge
sites. Included in this criterion are adverse impacts of weather and the
construction technologies required to reach a specific site. Construction risks anc
difficulties were rated relatively as “Minor”, “Moderate” or “Extensive”.
F.2.3.7 Cost
Capital Costs. Capital costs include the costs of corstructing facilities,
equipment replacement costs during the planning period plus 35 percent to cover
construction contingencies and administrative, engineering and legal costs. Capital
F -38
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costs of constructing an outfall to each of the alternative discharge sites are
presented in millions of dollars.
F.2.3.8 Materials Disposal
Disposal of Excavated Material. Both quantity and quality of excavated or tunneile
material was estimated to determine the potential difficulties associated with
disposal of the material. Disposal of the excavated or tunnelled materials was
rated based on the volume of material to be disposed and the degree of difficulty
associated with disposal.
F.2.3.9 Institutional
Construction Duration. This criterion examines the relative difficulty of’ a
specific discharge location/construction technology based on the expected time
required to complete the outfall construction.
Permitting. The number of permits required and the relative difficulty in obta nhig
these permits for each alternative was assessed. Ratings of “Moderate” aid
“Extensive” were assigned to each alternative, reflecting the relative difficulty of
permitting.
Demand for Unique or Scarce Construction Resources. The relative demar d that a-’
alternative may put on scarce resources or resources not available in the local area
was assessed. These resources include labor and construction materials which may be
in heavy demand due to other major local construction projects such as construct i
of the Third Harbor Tunnel. Potential conflicts exist for all alternatives. Thus,
the relative ratings assigned to the alternatives were either “Moderate” or
“Difficult”.
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F.3 EFFLUENT CONVEYANCE MODE
F.3.1 SCREENING PROCESS
Effluent from the new Deer Island wastewater treatment plant will be transported by
a submarine ocean outfall and discharged to a site in Boston Harbor/MassachUSer-S
Bay. Three potential outfall systems were screened using a set of relevant
criteria. For each criterion, an outfall system was rated relative to the other t
outfall system options. The screening ratings of the three possible systems were
compared and the alternative(s) with the least predicted impacts was selected for
detailed evaluation. If screening did not result in the elimination of’ options,
then all three outfall system options were to be evaluated in detail in this Draft
SEIS.
F.3.1.1 Description of Alternatives for Screening Analysis. The three constructio’i
technologies for the effluent outfall system proposed and evaluated by M’i RA %qere
marine pipeline, sunken tube and deep rock tunnel. These outfall construct1o ’
technologies represent a reasonable range of alternatives and were usec in the
screening for this Draft SEIS.
A marine pipeline outfall would require the use of barge-mounted equ prne it to
excavate a trench, lay a bed of stone withir the trench, lower and install the
pipeline sections, backfill the trench and cover the pipeline with store. The
sections would be between 10 and 20 feet in length. In addition, a statiorar:
trestle, located in near-shore shallow water, could be required to suDDort a
traveling crane on rails in the nearshore surf zone. This equipment would perfor
the same tasks as the barges.
The sunken tube method of construction would involve the installation of lengths of’
steel tube covered with concrete on both the exterior and interior surfaces of the
tube. These tube sections would be towed to the conveyance site and then surI : iflto
the excavated trench. Barge-mounted equipment (for deep water) and statior.ary
trestles (for shallow water) could be used in the same manner as in piDeilie
construction for trench excavation, stone bedding, backfilling and stone covering.
F L40
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The deep rock tunnel construction method would involve the construction of vertical
access shafts between 200 and 300 feet below the surface into the bedrock on Deer
Island. The tunnel would be constructed by either a tunnel bor Ing machine (TBM) or
by a TBM in combination with drill and blast methods. The bedrock wall of the
tunnel would then be lined with cast-in-place concrete or precast concrete liners.
MWRA examined both single and double conduits as possible effluent outfall
systems. A single conduit system was chosen. A single conduit system will have the
capacity to convey the wastewater from Deer Island to the discharge site and ili be
less costly and less difficult to implement and protect than a double conduit
system. Concrete is a durable material which will provide the tunnel with a smooth
interior and protect the conduit from corrosion and erosion.
F.3.1.2 Screening Criteria
Criteria were developed for screening the construction method for the effluent
outfall system which will transport effluent from the Deer Island treatment facility
to the discharge site in Massachusetts Bay.
F.3.1.2.1 Marine Ecosystem Impacts. Adverse impacts on water quality and aquatic
life are potential outcomes of the construction of the effluent outfall system.
These impacts, which should occur only during the construction phase of the project,
were assessed.
F.3.1.2.2 Impacts on Resources. This screening criterion addresses conduit
construction impacts on recreational and commercial resources of the harbor and ::s
shoreline. This criterion addresses potential impacts on boating, shipping.
fishing, shellfish harvesting, diving and use of beaches and parks. Most impacts on
valuable resources due to conduit construction are expected to occur in the v1c1r i::i
of the construction. Disturbances due to construction in adjacent areas woulo be
less severe but could result in adverse impacts such as noise, boating and shipp:r
interference, and transport of sediment or pollutants to sensitive areas.
F.3.1.2.3 Disposal of Dredged or Tunnelled Material. Excavated or tunnelled
material will be produced during either tunnel boring or trench excavation.
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Possible means of disposal were assessed for the pipeline, sunken tube and tunrel
conduit construction methods.
F.3.1.2)I Constructibility. This criterion qualitatively assesses the level of
difficulty involved in the implementation of each of the three conduit construction
techniques. Included in this criterion are time requirements for constructior
completion and potential for difficulties associated with construction.
F.3.1.2.5 Institutional Constraints. This criterion identifies coordination ard
permitting with other agencies or groups which could be required for each of the
outfall system construction technologies.
F.3.1.2.6 Cost. Cost estimates were made for each of the effluent conduit
construction alternatives.
F.3.1.3 Application of Criteria
Each outfall option was examined based on the above criteria and then rated relati ’e
to the other outfall system options.
F.3.1.3.1 Marine Ecosystem Impacts. Durlng the construction of a pipeline or a
sunken tube system, excavation of the trench would significantly increase turbidity
and suspended solids concentrations and negatively impact marine ecosystems in the
vicinity of construction. An increase in turbidity could adversely affect
phytoplankton which are at the beginning of the food chain; however, this impact
would probably be temporary and localized to the work site. Excavating a chanrel in
the Bay’s bottom surface could also increase sediment oxygen demand in the water
column. Benthic communities would be disturbed during the excavation and disposai
process. Upon completion of construction, the suspended matter would settle ar.d
water quality should improve. Trench excavation would likely cause a shift from
soft bottom to hard bottom habitat since the area would be backfilled with stor.e.
Upon completion of the trenched conduit construction, further impacts on water
quality and benthos would not be expected since the conduit system would be passive.
F-L 2
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It is anticipated that approximately 5.9L1, 9.12 and 11.145 million cu yds of material
would be dredged at Sites 2, LI and 5, respectively, and disposed at the Foul Area
Disposal Site, 20 miles east of Deer Island because of its large volume and the lac :
of suitable or available land disposal sites. Impacts such as burial of benthos,
temporarily increased turbidity and dissolved oxygen depressions, are expected with
ocean disposal, but if the material is relatively clean and is handled properly,
these impacts should be limited to the disposal site.
Drill and blast methods of trench excavation would disturb bottom sediments,
resulting in temporarily increased turbidity and suspended solids concentrations and
permanent loss of benthos habitat. Underwater explosions could kill or injure
fish. During drill and blast excavation, marine mammals would temporarily ayoid the
site, thus possibly interfering with their feeding or other activities.
No marine ecosystem impacts are expected in association with the deep rock tunnel
construction alternative, since the tunnelling of bedrock will occur below the
harbor’s bottom surface. Approximately 0.77, 1.28 and 1.86 million cu yds of
tunnelled material from Sites 2, 14 and 5, respectively, would be removed through the
aàcess shaft on Deer Island and disposed of on land. Based on marine ecosystetr
impacts, tunnel construction of the conduit is preferable since it will incur no
adverse impacts during construction of disposal. The pipeline and sunken tube
alternatives, which require extensive trench excavation and ocean disposal cf
excacQvated material, would cause severe impacts on water quality and aquatic life
in the vicinities of construction and disposal.
F.3.1.3.2 Impacts on Resources. Beaches and conservation land in :he vicinity cf
Deer Island and the outfall route could be indirectly affected by construction Cf
either the pipeline or the sunken tube conduit alternative since both invol’ 1 e
disturbing the sea floor (Figures F.3.a and F.3.b). In addition, sub r ec
vegetative habitat could be adversely affected by the trench excavated cor d . :t
construction. Construction of’ the pipe or tube conduit systems could disturb or-
water recreation and/or commerce such as fishing, shipping and other boating due tc
the presence of large construction equipment in the Bay. Deep rock tunnelling woud
have no impact on beaches, parks, valuable aquatic habitat or on-water activities
since the construction would be conducted under the harbor’s surface, througr t -e
underlying bedrock. Therefore, tunnelling is the preferred construction alternative
with respect to protection of resources.
F- 1 13
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NAL TCA.. M .ES
STATUTE MILES
\
- --If
The Graves
IsIar d
LEGEND
Recreational Beaches
Boston Harbor Island State Park
• Other Parks
ohasse
1’ p arbor
COHASSET ( I
Source: Boston Harbor Islands S a e PaP..
1956 Master Plan — Mass De—
MDC, 1984
MWRA, VOL V. App. L . 19S7
FIGURE F.3.a. BEACHES, SHORELP E PARKS, A D iSLAND PARKS
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Saltmarsh
Significant Identified areas of
-; I Submerged Vegetation

,,/,-,-//// Areas of Critical
Environmental Concern
____________ South Essex Ocean Sanctuary
• Marine Research Facilities
ROADS
Sources: MWRA Vol. V. APP.L, 1997
BARR, 1987
(Shelli i h Fled’ Sj 1 o n on F Iglire L). . .. i
(Bathing BtaiIie’ Sluim n on I Ipire I lid.
-J
NAUTIO L ES
1 0
—- STATUTE MILES
/
Is land
raves
Call
r%
LOvS II
Island
GaHo s Georges
Island Island
0
LEGEND
FIGURE F.3.b. SENSITIVE HARBOR RESOURCES
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F.3.1.3.3 Disposal of Dredged or Tunnelled Material. Sediment dredged dur rg
either pipeline or sunken tube trench excavation would have to be dumped at the Foul
Area Disposal Site. Dredging and disposal at this site requires permitting througr
the U.S. Army Corps of Engineers and U.S. EPA. Prior to receiving permission to
dispose the excavated material at the Foul Area Disposal Site, the sediment s
chemical, physical and biological characteristics must be analyzed to meet ocean
dumping requirements. If’ the sediment is judged to be unsuitable for ocean
disposal, then on-land disposal arrangements must be made. Less coritan’ir.ated
sediments could be landfilled while highly contaminated sediments would be disposed
according to hazardous waste regulations. With a pipeline or sunken tube,
approximately 5.91 1, 9.12 and 11.115 million cu. yds of dredged material from Sites 2,
14 and 5, respectively, would be disposed at the Foul Area. With a deep rock tunnel,
approximately 0.77, 1.28 and 1.86 million cu. yds of tunnelled material frorr Sites
2, LI and 5, respectively, would be removed from the outfall via the Deer Island
access shaft. This material could be used in local construction projects such as
construction of the Third Harbor Tunnel. Unused tunnelled material wou1.d be
disposed at an on-land disposal site.
Disposal of dredged or tunnelled material from any of the three construction options
which would be difficult. Disposal of dredged material at the Foul Area wouid
require an involved permitting process. On-land disposal sites for the tunreilec
material have not yet been finalized. Identifying these sites will be difficult.
In addition, on—land disposal will become increasingly difficult with volume as
supply of the low-strength aggregate exceeds demand.
F.3.1.3. 1 1 Constructibility. A tunnelled outfall system from Deer island t ti-c
discharge site must slope back towards Deer Island to allow for the pumping of
groundwater seepage from the conduit. The construction of a pipeline or sunker tube
outfall system would require excavation of a trench through the irregular topograpi-y
of the harbor’s bottom surface. Due to the uncertainty associated with ti-c
requirements of the trench excavation and possible rock excavation, the alternatives
of a pipeline or sunken tube outfall system are considered difficult. The pipe and
tube construction methods would be interruoted during periods of poor weacrier.
F- 1 16
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F.3.1.3.5 Institutional Constraints. Construction involving a pipeline or sunken
tube could impact the harbor’s islands and would also require permits with
Massachusetts Coastal Zone Management and Massachusetts Department of Environmentai
Quality Engineering (DEQE). DEQE would require a Chapter 91 review, a dredging
permit and a state water quality certification. Trench excavation and disposal
would require a permit from the U.S. Army Corps of Engineers. Dredging would also
require a Section 106 Review by the State Historic Preservation Office to assess
potential impacts on archaeological and cultural resources.
Deep rock tunnelling would not affect shipping or the harbor’s islands since all
construction would be underground. No dredjing would be involved in the
constructIon of a deep rock tunnel. Pipeline, sunken tube, and deep rock tunnelling
construction methods all would require a permit from the U.S. Army Corps of
Engineers under Section 10 of the River and Harbor Act (Appendix G). Pipeline or
sunken tube construction would generate significantly larger volumes of excavated
material than would tunnelling. Disposal of material excavated during pipeline or
sunken tube construction would therefore be more involved than disposal of tunnelled
material. Boring a tunnel through bedrock would require the least coordination t. itr
pertinent agencies or organizations.
F.3.1.3.6 Cost. MWRA estimated the cost of constructing each of the three
conveyance system options based on an outfall length of 20,000 feet. Comparisons of’
the three effluent outfall system alternatives (Table F.3.a) indicate that the least
costly alternative to a site 20,000 feet seaward from Deer Island is the deep rock
tunnel from the treatment plant to the discharge site. Based on tIWRA’s estimates.
construction cost would be $5,650 per linear foot for the tunnelled conduit, $10,300
per linear foot for the pipeline conduit and $13,300 per linear foot for the sunken
tube conduit. Pipeline construction would be approximately 82 percent more costiy
and sunken tube construction would be approximately 135 percent more costly than
tunnel construction of the outfall system.
F.3.1. I Siimm ry
Based on the application of the above criteria, the deep rock tunnel construction
alternative would least impact environmental quality and harbor resources. be most
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TABLE F.3.a. CONSTRUCTION COSTS OF THE ALTERNATIVE OUTFALL SYSTEMS 1
Description
Cost ($ n’ ilion)
Tunnel
113
Pipeline
206
Sunken Tube
266
1. Costs based on construction of a 20,000-ft conduit.
adaptable to future uses of the harbor, be easiest to construct, have the least
institutional constraints, and be the least costly of the three effluent outfall
alternatives (Table F.3.b). Therefore, tunnel construction was the only alternati c
selected for further evaluation.
F.3.2 DESCRIPTION OF OUTFALL CONDUIT ALTERNATIVE FOR DETAILED EVALUATION
A single effluent conveyance mode was selected for detailed evaluation in this Draft
SEIS. This outfall alternative involves deep rock tunnelling from Deer Island to
the discharge location, and includes a 30—foot by 15-foot rectangular verz ca.
access shaft on Deer Island and a 25-foot finished inside diameter concrete-liied
tunnel which would be connected to the access shaft (MWRA, STFP V,E, 1967). fl-c
tunnel could either end below the beginning of a pipeline diffuser or below the last
diffuser riser of a tunnelled diffuser. The length of the tunnel would be betweer
28,000 and 5L ,000 feet, depending upon the diffuser design and location of the
discharge site.
In constructing the outfall tunnel, a vertical shaft would be excavated on De. r
Island from grade to the tunnel. Excavation of’ the shaft would proceed with the se
of’ traditional excavation machines and drill and blast techniques. The vertical
shaft would be excavated deep enough to allow for a 0.25 percent (or less) pOsitivC
sloping tunnel and to assure a minimum of 60 feet of’ bedrock overlying the outfall
tunnel. The positive sloping conduit would act as a sur p enabling the removal cf
leaking groundwater during construction and deposited solids during o era:ior.
Support of the soil would be necessary to excavate the access shaft on Deer
Island. Such support could be provided by steel sheet piling driven througi the
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TABLE F3.b. SUMMARY OF EFFLUENT CONVEYANCE MODE SCREENING
Screening Criteria/
Effluent Conveyance Mode Tunnel Sunken Tube Pipeline
Marine Ecosystem No Impact Negative Impact Negative Impact
(0) (-) (-)
Impacts on Resources No Impact Negative Impact Negative Impact
(0) (—) (—)
Disposa] of Excavated Material Difficult Difficult Difficult
(-) (-) (-)
Constructibility Difficult Difficult Difficult
(—) (—) (—)
Institutional Constraints Possible Definite Definite
(0/—) (—) (—)
Cost Expensive More Expensive More Expensive
(0) (—) (—)
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soil and into the bedrock prior to excavation or concrete caissons driven into the
soil during excavation.
The outfall conduit would be mined using a tunnel boring machine (TBM) (MWR [ , STFP
V,E, 1987). In some areas, drill and blast techniques may also be rnplemer.:ed.
Tunnel excavate from excavation of the access shaft and outfall syster will be
removed through the access shaft on Deer Island. The medium-hard rock, Carnoridgc
argillite, is the most common rock type in Boston Harbor/Massachusetts Bay. it
anticipated that the TBM will progress an average of 50 to 70 feet/day in the tun.el
construction and that approximately 15 percent of the tunnel will require support
such as rock bolting and grouting. These estimates are based upon the available
data and may be revised pending KWRA’s detailed geologic investigations planned for
spring 1988.
The tunnel system would be lined with reinforced concrete to provide a smooth
conduit wall and thus minimize friction head loss. The conduit lining will be
precast concrete sections.
F.3.3 CRITERIA FOR DETAILED EVALUATION
The tunnelled outfall alternative was evalLated in detail using the set of seiec:io’
criteria described below.
F.3.3.1 Environmental
Air Emissions Control. A r emissions control qualitatively addresses the potentIal
for generating air emissions and odor during conduit construction. This crite” on
qualitatively rates impacts due to conduit construction as either “Mitigable” or
“Not Mitigable”.
Noise Control. Noise could adversely affect marine biota as well as coastline areas
which are used for commercial or recreational purposes. Sources of noise dur: g
construction would be construction of the shaft on Deer Island. The criterion of
noise control will quantitatively assesses the noise due to shaft construction an
qualitatively assigns an impact rating of “Minor”, “Moderate” or “Extens:ve”.
F-50
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F.3.3.2 Engineering Feasibility
Reliability. This criterion assesses the ability of the conduit syste n to
continuously operate over the expected range of conditions during the life of the
design. Relative ratings were established using measurements of’ “Reliable” or “No:
Reliable”.
Constructibility. The criterion of constructibility assesses the difficulty and
risk associated with constructing the conduit system. Included in this criterion
are adverse impacts of weather and construction technology involved. Construction
risks and difficulties were qualitatively rated as “Minor”, “Moderate” or
“Extensive”.
F.3.3.3 Cost
Capital Cost. Capital cost presents the sum of the costs required to construct arid
operate the project as a single ir vestr ent. This cost includes capital cost of the
project through the year 2020 and is measured in millions of dollars.
F.3.3.’I Materials Disposal
Disposal of Tunnelled Material. It is anticipated that tunnelled material wlll be
removed through the access shaft on Deer Island and be disposed at an on-land
site. Disposal of the tunnelled material was rated based on the volume of material
to be disposed and the degree of’ dlfficulty associated with disposal.
F.3.3.5 Institutional
Construction Duration. This criterion examines the relative difficulty of a spec f c
construction technology based on the expected time required for completion o ’
construction.
Permitting. The number of permits required and the relative difficulty ir obtalning
these permits for each alternative was assessed. A rating of’ “Moderate” or
“Extensive” was assigned reflecting the relative difficulty of permitting assoclated
with the alternative.
F-5 1
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Demand for Unique or Scarce Construction Resources. The relative demand that ar
alternative may put on scarce resources or resources not available in the local area
was assessed. These resources include labor and construction materials which may te
in heavy demand due to other major local construction projects such as construct 101
of the Third Harbor Tunnel. The alternative was qualitatively rated as either
“Moderate” or “Difficult”.
F.3.3.6 Harbor Resources
Protection of Cultural and Historical Resources. The potential to protect areas of’
cultural or historical value was assessed for the conduit construction
alternative. Included in this assessment was potential impacts on archaeoJ ..ogy and
historic resources such as shipwrecks. A relative rating of “Minor”, “Moderate” or
“Extensive” was assigned to the alternative.
Water Traffic. Interference with marine traffic as a result of construction will be
examined. Water traffic interference is related to the amount of time which nar: e
traffic would be disturbed during the construction project. Measuremert of this
criterion was made on a relative basis with “Minor”, “Moderate” or “Extensive” as a
rating.
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F. 1 1 DIFFUSER TYPES
F. 1 L.1 SCREENING PROCESS
At the end of the ocean outfall, the effluent will be discharged through a
diffuser. Effluent will be expelled through the diffuser openings (or ports) ar
will mix with the surrounding seawater. The use of diffusers is an efficient method
to provide initial dilution of a waste in an area such as Massachusetts Bay.
Three potential diffuser systems were screened using a set of relevant criteria.
For each criterion, an outfall system was rated relative to the other two dlffLser
options. The ratings of each of the possible diffuser systems were compared and the
alternative with the least predicted impacts was to be selected for aeta led
evaluation. If screening did not result in the elimination of options, then all
three diffuser options, or some combination of the three options, were to be
evaluated in detail in this Draft SEIS.
F.ZL1.1 Description of Alternatives for Screening Analysis
MWRA proposed and evaluated three diffuser alternatives (MWRA, STE? V,D, 1987).
These options represent a range of diffuser construction technologies and riser
configurations. This Draft SEIS examined those diffuser alternatives whic 1 ’. t ..ere
discussed by MWRA and are also compatible with the preferred outfall system
alternative as screened in Section F.3 of this Appendix.
The first diffuser option is a pipeline situated witriin an e . cavated trerc
connected to the deep rock tunnel outfall by one riser. Ports or nozzles woLId
either be cast into or attached to the pipe (Figure F.LI.a). A second d ffuse
construction technology involves a deep rock tunnel outfall with approxlmatei::
10 risers each about 2 meters in diameter. Each individual riser would connect zh.e
tunnel to a small (1 to 1.5 meter diameter) diffuser pipe extending about 100 me:ers
in opposing directions. The diffuser pipes would discharge in alterna: -g
directions (Figure F.LI.b). The last diffuser option involves maly risers
(approximately 80). A platform would be constructed at the discharge site and t e
F-53
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II(;UR.F. F.4.a. PROFILE VIEW OF PiPELINE l)1FFUSER WITh ONE RISER
RISER
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Fi(;i IR I !.4.h. PROFI 1K VIEW o ’ I’IrI U NE 1)1 vii’iu EIGhT ‘10 TEN RiSI S
RISER
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risers would be drilled through the overlying sediment and bedrock and then attached
to the tunnelled outfall. Each riser would be fitted with a multi-port cap (be:we n
8 and O ports) (Figure F.lLc).
F. 1 L1.2 Screening Criteria
Criteria were developed for screening the techniques proposed in the cons:ructio of
the diffuser system which will discharge effluent in Massachusetts Bay. It is
assumed that operation of the three diffuser options would be identical. Thus, only
construction impacts were addressed by the diffuser system screening criteria.
Costs for alternative diffuser systems cannot be determined without site-speclflc
geotechnical information. Therefore, costs are not used to compare diffuser
alternatives in this Draft SEIS.
F. 1 1.1.2.1 Marine Ecosystem Impacts. Adverse impacts on water quality and aquatlc
life are potential outcomes of the construction of the effluent diffuser system.
Thus, environmental impacts were assessed to determine the severity of impacts
associated with each diffuser option.
F. 1 L1.2.2 Impacts on Resources. This screening criterion addresses impacts on
recreational and commercial resources of the harbor and its shoreline due to tr e
construction of each diffuser option. The criterion addresses potential impacts on
boating, shipping, fishing, shellfish harvesting, diving and use of beacries a d
parks. Most impacts on valuable resources due to the diffuser are expected to occur
in the vicinity of the construction. Disturbances due to constructicn in adjacent
areas could result in impacts such as noise, boating and shipping interference, aid
transport of sediment or pollutants to sensitive areas, but would be less severe.
F.II.1.2.3 Constructibility. This criterion qualitatively assesses the level of
difficulty involved in the implementation of each of the three diffuser construc:io
options. Included in this criterion are time requirements for construction aid
potential for difficulties associated with construction.
F. 1 1.1.2. 1 4 Operational Complexity. Prior to the start-up of an outfall/diffuser
system or during periods of low flow, saltwater may flood the diffuser. if the
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SEA LEVIL EL lOS FT
PLAN OF RISER CAP
PITS
SOURCE: MWRA STFP V. 1987
6600 FT DIFFUSER -
80 EQUALLY SPACED RISERS
DETAIL A-
SC*Lc rET
0 SO
I
A
SECTION
NT S
RISER CAP
(TYP 60 PLACES
120
1’I(I Ill I V_ic. PlAN AN I) PROM I K VII WS OF TLJN N El,I.l l) 1)1 Vl’I ISEI{ WITI I Mu ITlI’t,E II I
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system is unable to periodically rid, or purge, itself of the saltwater intrusion,
the outfall/diffuser system will not operate properly. Wastewater would be
discharged from fewer ports and therefore there would be a loss in dilut oi
efficiency. By falling to purge the system of the seawater during peak flows.
seawater inflow could occur through some risers while through others, effluent would
be flowing out. The criterion of operat:onal complexity focuses pr:mar c
purging requirements for the three diffuser design options. In addition, this
criterion considers potential damage to the diffuser as a result of wave actio .
anchors or commercial fish trawling operations.
F. 1 1.1.2.5 Institutional Constraints. This criterion identifies coordinat cr t .. :h
other agencies or groups which could be required for the constructlon arc opera:lon
of each of the three diffuser systems.
F.IL1.3 Application of Criteria
Each diffuser option was examined based on the above criteria and then rated
relative to the other options.
F. 1 I.1.3.1 Marine Ecosystem Impacts. During the construction of a pipeline diffuser
system, dredging of the trench would significantly increase turbidity arc suspenced
solids concentrations and negatively impact marine ecosystems in the vicinity of
construction. In addition, drill and blast methods of excavation could disturD
bottom sediments, resulting in temporarily increased turbidity and suspended solids
concentrations and permanent loss of benthos habitat. Underwater explosions would
have adverse impacts on fish during the construction period. An increase
turbidity could adversely affect phytoplankton which are at the beginnlng of the
food chain; however, this impact would probably be temporary. Excavating a charnel
in the sea floor could also increase sediment oxygen demand and reintroduce settled
sediments to the water column. Benthic communities would be disturoed durir.g the
excavation process. It is likely the 1.4 million cu. yds. of dredged material
obtained during trench excavation would be disposed at the Foul Area Disposal Site
where benthic habitat would be temporarily lost during disposal.
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Less adverse impacts on the marine ecosystem are expected in association with the
construction of a deep rock tunnel diffuser with numerous risers. The reason for
this is that tunnelling of bedrock will occur below the harbor’s bottom surface and
riser drilling will involve the excavation of a total of only 12,000 cu. yc. of
material. Approximately 150 cu. yds of material would be disposed every one to two
weeks over the four to five year construction period. The material dredged C i
the drilling of risers would be disposed at the Foul Area Disposal Site. One or
more risers extending from a tunnel to a diffuser pipe situated in a trencr , wo .d
require excavation of 1.14 million cu. yds. of sediment, resulting in a significant
loss of benthic habitat and an increase in suspended solids concentration and
turbidity. This would also incur a larger loss of benthic habitat at the Foul ( rea
Disposal Site.
F.i4.1.3.2 Impacts on Resources. While it is unlikely, all three diffuser options
could potentially affect conservation land and submerged vegetative habitat curing
construction since they require some above surface construction. In addition.
construction and operation of the various diffuser types could interfere with
commercial fishing activities. The alternative involving a deep rock tunnel With
risers only would require the least amount of sea floor construction and thus would
be least likely to impact resources. Fewer impacts affecting recreation and
commerce are expected with the drilled riser diffuser versus the trenched pipeline
diffusers since less sediment would be disturbed during the construction process.
F.’I.1.3.3 Constructibility. It is anticipated that weather related down-tirre will
occur during four months of each year of construction of each of the d ff ser
systems. Trench excavation for a pipeline diffuser could require the use of a
clamshell digger, rather than standard dredging equipment, due to the large wa:e”
depth at sites 14 and 5. Excavation using a clamshell digger is expected to tave
longer than excavation with dredging equipment. Each of the 80 drilled risers n
the drilled riser diffuser option is expected to require 1 to 1 1/2 weeks to drill.
F.’L1.3. Operational Complexity. The requirement of purging seawater from the
diffuser system is an important issue for all of the diffuser options except for the
one involving the construction of one large riser connecting the tunnelled outfall
to the trenched pipeline diffuser. While this alternative would require some
F-59
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purging and intrusion control, hydraulic analyses indicate that the need for sich
control will be minimal (MWRA, STFP V,D, 1987). In addition, all of the diffuser
options are at risk of being damaged by wave action, anchors and commercial fish
trawling operations. The option of a tunnelled diffuser with numerous multi-port
risers is least likely to be damaged, however, since this option has the least
amount of its system exposed to such elements.
F. 1 L1.3.5 Institutional Constraints. Dredging and ocean disposal associated with
diffuser construction would require permiting from the U.S. Army Corps of’ Engineers
and U.S. EPA.
F. 1 I.1. 1 Sirnmi ry
The diffuser construction alternative involving 80 risers drilled through bedrock
and connected to the tunnelled outfall would have the least marine ecosystem and
harbor resources impacts of the three effluent outfall alternatives (Table F.LI.a).
However, based on the application of the other screening criteria, it is difficult
to choose one preferred option. All options are expected to be difficult to
construct, be costly, and require permitting through various agencies. Therefore,
no diffuser construction technologies were eliminated during screening.
F. 1 L2 DESCRIPTION OF DIFFUSER ALTERNATIVES FOR DETAILED EVALUATION
Two diffuser construction alternatives which were chosen for detailed evaluatio- in
Chapter 5 of this Draft SEIS. The first alternative was a tunnelled diffuser wiz h
80 risers drilled through the overlying sediment and bedrock and attached to t e
tunnelled outfall. Each riser would be fitted with a multi-port cap. The second
diffuser alternative was a combination of the other two alternatives evaluated in
the screening process. This alternative was a tunnelled outfall connected to a
pipeline diffuser by one to ten risers.
F.’I.3 CRITERIA FOR DETAILED EVALUATION
The effluent diffuser alternative was evaluated in detail in Chapter 5 using tne
selection criteria described below.
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t4arlne Ecosystem
Impacts on Resources
1
0 ’
Constructibility
Operational Complexity
(Purging/External Damage)
Institutional Constraints
TABLE F.Il.a. SU)1ARY OF DIFFUSER TYPE SCREENING
Alternative 1: Tunnel with
One Riser to Pipeline Alternative 2: Tunnel with
Diffuser with Multiple Ten Risers To Ten
Ports or No7zIes Pipe Diffusers
Extreme Extreme
Negative Impact Negative Impact
(—) (—)
Negative Impact Negative Impact
(—) (—)
Difficult Difficult
(—) (—)
Minimal Purging Requlred/ Purging Required/External
External Damage Possible Damage Possible
(+1—) (—/—)
Probable Probable
(—) (—)
Alternative 3: Tunnel with
= 80 Risers Through Bedrock
Multi-Port Riser Caps (8 Ports )
Minor
Less Negative Impact
(0)
Less Negative Impact
(0)
Difficult
(—)
Purging Requlred/
Least External Damage
Probable
(—)
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F.Z .3. 1 Environmental
Noise Control. Noise may adversely affect marine biota as well as coastline areas
used for commercial or recreational purposes. Noise during construction could
result from excavating and drilling. The criterion of noise control quantitatlve.y
assesses the noise due to diffuser construction and qualitatively assigns the
construction a rating of “Minor”, “Moderate” or “Extensive”.
F.lI.3.2 Engineering Feasibility
Reliability. This criterion assesses the ability of the diffuser system to
continuously operate over the expected range of conditions during the life of :r e
design. Relative ratings were established using measurements of “Reliable” or “ ct
Reliable”.
Constructibility. The criterion of constructibility assesses the difficulty ar.
risk associated with constructing the diffuser system. Included ir this criterion
are adverse impacts of weather and construction technology. Construction risks a- :
difficulties were qualitatively rated as “Minor”, “Moderate” or “Extensive”.
F. 1 L3.3 Materials Disposal
Disposal of Excavated Material. Disposal of the excavated materials was ratea bas i
on the volume of material to be disposed and the degree of difficulty assoc:a:e
with disposal.
F.’I.3) Institutional
Construction Duration. This criterion examines the relative difficulty o ’ a
specific diffuser construction technology based on the expected time requirec fo-
completion of’ construction.
Permitting. The number of per nts required and the relative difficulty in obta n
these permits for each alternative was assessed. Ratings of “Moderate” o
“Extensive” were assigned to each alternative, reflecting the relative d ff culty of’
permitting.
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Demand for Unique or Scarce Construction Resources. The relative demand that ar
alternative may put on scarce resources or resources not available irr the local area
was assessed. These resources include labor and construction materials which ma.’ be
in heavy demand due to other major local construction projects such as construction
of the Third Harbor Tunnel. Alternatives were rated as either “Moderate” or
“Difficult”.
F.Zt.3.5 Marine Ecosystem
Protection of Water Quality. Construction of the diffuser has the potential to
disturb bottom sediments, causing them to resuspend and to increase turbidity. The
relative impact which each diffuser option would have on water quality waS
assessed. This criterion was qualitatively measured using ratings of “Minor’,
“Moderate” or “Extensive”.
Protection of Sensitive Biota arid Habitat. Resuspension of bottom sed rnents and
loss of habitat are expected to result from the construction of the diffuser. The
extent to which these disturbances would impact sensitive biota and habitat was
qualitatively assessed using ratings of “Minor”, “Moderate” or “Extensive”.
F. 1 I.3.6 Harbor Resources
Protection of Cultural and Historical Resources. The potential to protect areas of
cultural or historical value was assessed for each diffuser constructio
alternative. Included in this assessment was potential impacts on archaeology anc
historic resources such as shipwrecks. Relative ratings of “Minor”, “Moderate” or
“Extensive” were assigned to each alternative.
Water Traffic. Interference with marine traffic as a result of construction will be
examined. Water traffic interference is related to the amount of time which marine
traffic would be disturbed during the construction project due to the type of
construction selected for the project. Measurement of this criterion was made on a
relative basis with “Minor”, “Moderate” and “Extensive” as ratings.
F-63
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Protection of Commercial Fishing Activities. Potential interference with commercial
fishing activities such as dragging, trawling, gilinetting and lobstering ar
preemption of fishing areas was examined. The alternative diffuser types were rated
as either “Minor”, “Moderate” or “Extensive”, depending on the impact predicted.
F.5 INTER-ISLAND CONVEYANCE MODE
F.5.1 SCREENING PROCESS
Wastewater entering the South System of the MWRA collection and treatmer’t syster
will initially be treated by screening and grit removal at the proposed head. .orks on
Nut Island. From Nut Island, the wastewater will be conveyed to Deer Isi nd, t e
location of the new wastewater treatment plant, via an inter-island conveyance
system.
Three potential inter-island conveyance systems were screened using a set of
relevant criteria. For each criterion, a conveyance system was rated reia:lve to
the other two inter-island conveyance system options. The screening ratings of tie
three possible systems were compared and the alternative(s) with the least predic:ed
impacts was selected for detailed evaluation. If screening a d not result i t-e
elimination of options, then all three inter-island conveyance system options were
to be evaluated in detail in this Draft SEIS.
F.5.1.1 Description of Alternatives for Screening Analysis
Prior to selecting the inter-island conveyance system from Nut Islanc to Deer
Island, MWRI proposed and examined three construction technologies: mari’ e
pipeline, sunken tube and deep rock tunnel (MWRA STFP IV, 1987). These alternatives
use the same construction technologies presented for the effluent outfall sys:eT
except that the deep rock tunnel construction method would involve the construccic
of vertical access shafts on both Nut and Deer Islands. These inter-isIa d
construction modes represent a reasonable range of alternatives and were used ir
this Draft SEIS.
F - 6 4
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Since President Roads is a major shipping lane of Boston Harbor, construction of’
either a pipeline or a sunken tube would have to be coordinated with the U.S. Coast
Guard to prevent unsafe conditions in the harbor. In addition, construction
involving a pipeline or sunken tube may impact the harbor’s islands and may require
coordination with Massachusetts Coastal Zone Management. This is in addition to the
dredging and disposal permits which would also be required. Therefore, only
tunnelled conveyance construction will be considered for the portion of the inter-
island conduit from Long Island to Deer Island, or President Roads.
F.5.1.2 Screening Criteria
Criteria were developed for screening the techniques proposed in the construction of
the inter-island conveyance system which will transport wastewater from Nut Islar :
to the secondary treatment facility on Deer Island.
F.5.1.2.1 Marine Ecosystem Impacts. Adverse impacts on water quality and aquatic
life are potential outcomes of the construction of an inter-island conveyance systen
between Nut Island and Deer Island. These impacts, which should occur only durlng
the construction phase of the project, were assessed.
The most severe environmental impacts due to conduit construction are precicted to
be short—term, however the area would be altered from its orlginai state and thus
there could also be some less severe but long-term env ronmer tal lmpacts associated
with conduit construction.
F.5.1.2.2 Impacts on Resources. This screening criterion addresses conc ::
construction impacts on recreational and commercial resources of the harbor and its
shoreline. This criterion addresses potential impacts on boating, shipp ’-ig,
fishing, shellfish harvesting, diving and use of beaches and parks. Most impacts o
valuable resources due to conduit construction are expected to occur in the vicinlty
of the construction. Disturbances due to construction in adjacent areas would be
less severe but could result in adverse impacts such as noise, boating and ShiPpinC
interference, and transport of sediment or pollutants to sensitive areas.
F-65
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F.5.1.2.3 Disposal of Dredged or Tunnelled Material. Excavated or tunnelled
materials will be produced during either tunnel boring or trench excavation.
Possible means of’ disposal were addressed for the three inter-island coidu :
construction methods.
F.5.1.2. 1 1 Constructibility. This criterion qualitatively assesses the level of
difficulty involved in the implementation of each of the three conduit constructlo’.
techniques. Included in this criterion are time requirements for constructior a d
potential for difficulties associated with construction.
F.5.1.2.5 Institutional Constraints. This criterion identifies coordination a d
permItting with other agencies or groups which could be requlred for eac i of tne
inter—island conveyance system construction technologies.
F.5.1.2.6 Cost. Cost estimates were made for each of the inter-islanc conveyance
system alternatives.
F.5.1.3 Application of Criteria
Each inter-island conveyance system option was examined based on the above criteria
and then rated relative to the other options.
F.5.1.3.1 Marine Ecosystem Impacts. During the construction of a pipeline or a
sunken tube system, excavation of the trench would significantly increase turbid::
and suspended solids concentrations and negatively impact marine ecosystems in the
vicinity of construction. An increase in turbidity could adversely affec:
phytoplankton which are at the beginning of the food chain; however, this n ac:
would probably be temporary and localized to the work site. Excavating a channel i-i
the harbor’s bottom surface could also increase sediment oxygen demand a-:
reintroduce settled pollutants in the bottom sediment to the water column. The
harbor’s bottom sediments are polluted and support pollution tolerant species. Tne
potential for disturbance of contaminated sediment could require extens:ie
precautions during dredging.
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Benthic communities would be disturbed during the excavation and disposal process.
Upon completion of construction, the suspended matter would settle and water quality
should improve. Trench excavation would likely cause a shift from soft bottom to
hard bottom habitat since the area would be backfilled with stone. Upon completion
of the trenched conduit construction, further impacts on water quality and benthos
would not be expected since the conduit system would be passive.
It is anticipated that approximately 1.5 million cu. yds. of material would be
dredged during construction and disposed at the Foul Area Disposal Site 20 miles
east of Deer Island because of its large volume and the lack of suitable or
available land disposal sites. Impacts such as burial of benthos, temporarily
increased turbidity and dissolved oxygen depressions are expected with oceai
disposal, but if the material is relatively clean and is handled properl q, these
impacts should be limited to the disposal site.
Drill and blast methods of trench excavation could disturb bottom sediments,
resulting in temporarily increased turbidity and suspended solids concentrations and
permanent loss of benthos habitat. Underwater explosions could kill or inJure
fish. During drill and blast trench excavation, marine wildlife would temporarily
avoid the site, thus possibly interfering with their feeding or other act vit1es.
Few or no marine ecosystem impacts are expected in association with the deep rocl :
tunnel construction alternative since the tunnelling of bedrock will occur below the
harbor’s bottom surface. Approximately 914,000 cu. yds. of tunnelled material would
be removed during construction of the pipeline/tunnel or sunken tube/tunnel inter-
island conduit options. Approximately 197,000 cu. yds. of tunnelled rnaterial would
be removed during construction of the tunnelled conduit system. Tunnelled material
would be removed through an access shaft on Deer Island and used during the site
preparation of the construction on Deer Island.
Based on marine ecosystem impacts, tunnel construction of the conduit is preferable
since it will incur no adverse impacts during construction or disposal. The
pipeline and sunken tube alternatives, which require extensive trench excavation and
ocean disposal of excavated material would cause severe impacts on water quality and
aquatic life in the vicinities of the construction and disposal sites.
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F.5.1.3.2 Impacts on Resources. Both the pipeline and the sunken tube condu:t
construction alternatives involve disturbing the sea floor, which could potentially
affect beaches and conservation land located en route between Nut Island and Deer
Island such as those located on Peddocks Island, Long Island and Rairisford Island.
In addition, submerged vegetation which could be adversely affected by disturb:ng
the sea floor during conduit construction. Construction of the pipe or tube cordL::
systems could disturb on-water recreation and/or commerce such as fishing, shipp rg
and other boating, due to the presence of large equipment in the Harbor. Deep rock
tunnelling would have no impact on beaches, parks, valuable habitat or on-water
activities since the construction would be conducted under the harbor’s surface,
through the underlying bedrock. Therefore, tunnelling is the preferred constructior’
alternative with respect to protection of resources.
F.5.1.3.3 Disposal of Dredged or Tunnelled Material. Sediment dredged curlrg
either pipeline or sunken tube trench excavation would have to be dumped at the Foul
Area Disposal Site. Dredging and disposal at this site requires permitting through
the U.S. Army Corps of Engineers and U.S. EPA.
Tunnel excavate would be removed from the inter-island conveyance conduit through
the Deer Island access shaft and be used during the site preparation for the
construction of the new Deer Island wastewater treatment facilities (MWRA, STFP IV,
1987). Disposal of dredged material from the trenched excavation at the Foul Area
Disposal Site would require an involved permitting process and therefore would be
difficult.
F.5.1.3) Constructibility. A tunnelled conveyance system betweer Nut. Islar c aric
Deer Island will slope downward towards Deer Island so that wastewater can flo
freely downhill to Deer Island, where it will be pumped up to the treatment plant.
In addition, the slope would act as a sump to collect the groundwater which leaks
into the conduit during construction. The pipe or tube construction methods would
be interrupted during periods of poor weather. Weather should not affect tne tunre
construction. MWRA (MWRA, STFP IV, 1987) predicted that the sunken tube would be
the most time-consuming of the three inter-island conveyance alternatives.
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F.5.1.3.5 Institutional Constraints. Construction involving a pipeline or sunker
tube would require a Chapter 91 review, a dredging permit and a state water quality
standard permit from Mass. DEQE. Trench excavation and disposal would require a
disposal permit from the U.S. Army Corps of Engineers. Deep rock tunneling would
not affect shipping or the harbor’s islands since all construction would be
underground. No dredging would be involved in the construction of a deep rcc
tunnel. If an EIS is required for the designation of an ocean disposal site for the
tunnel excavate, then construction of the inter-island conddit systen could e
delayed. Pipeline or sunken tube construction would generate significantly larger
volumes of excavated material than would tunnelling. Disposal of material excavatec
during pipeline or sunken tube construction would therefore be more involved thar
disposal of tunnel excavate which would be confined to Deer Island. Boring a tunrei
through bedrock would require the least coordination with pertinent agerkies or
organizations.
F.5.1.3.6 Cost. The inter-island conveyance system alternatives are a deep rock
tunnel between Long Island and Deer Island. along with either a pipeline, sur.k’er
tube or deep rock tunnel from Nut Island to Long Island. M14RA estimated preselt
worth and project costs for each of the three options. Present worth cost
represents all of the costs incurred in the construction and operation of the
diffuser, presented as one equivalent initial investment. Project costs represe’:
the estimated capital costs, in September 1986 dollars, including 35 percent for
engineering and contingencies.
Comparison of costs of the inter-island conduit alternatives (Table F.5.a) indicates
that the least costly alternative s the deep rock tunnel from Nut Island to Deer
Island. The pipeline/tunnel alternative is approximately 79 percent more costly
than the tunnelled inter-island conveyance system. Similarly, the sunker.
tube/tunnel alternative is approximately 172 percent more expensive than the
tunnelled alternative. In addition to cost of the conduit, the cost of the South
System pumping station (Table F.5.b) would also be included in the total cost of the
inter-island conveyance system.
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TABLE F.5.a SUMMARY OF INTER-ISLAND CONVEYANCE SYSTEM ALTERNATIVES
Present Worth Project
Cost Cost
Alternative ($ Million) ($ Million)
Tunnel-Nut Island
to Deer Island 63 83
Pipeline—Nut Island to
Long Island 113 1L 18
Tunnel-Long Island to
Deer Island
Sunken Tube-Nut Island
to Long Island 172 225
Tunnel-Long Island
to Deer Island
Source: KWRA STFP IV, 1987
TABLE F.5.b COSTS OF THE SOUTH SYSTEM PUMPING STATION
Cost $Millions
Present Worth 38.0
Project 37.5
Annual 0&M 1.3
Source: MWRA STFP V, 1987.
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F.5.1. 1 1 Stinm ry
Based on the application of the above criteria, the deep rock tunnel construction
alternative would least impact environmental quality and harbor resources, be most
adaptable to future uses of the harbor, be easiest to construct, have the least
institutional constraints, and be the least costly of the three inter-island coidu t
alternatives (Table F.5.c). Therefore, tunnel construction from Nut Island to Deer
Island was the only alternative selected for further evaluation.
F.5.2 DESCRIPTION OF INTER-ISLAND CONDUIT ALTERNATIVE FOR DETAILED EVALUATION
The single inter-island conveyance alternative selected for detailed evaluation is
an 11—ft finished inside diameter deep rock tunnel from Nut Island to Dee’ Isla:
(Figures F.5.a and F.5.b) (t4WRA, STFP IV, 1987). This alternative would involve
similar tunnelling methods described for the tunnelled outfall system alternative
(Section F.3.2). Vertical access shafts would be excavated on Deer Island and Nut
Island. Excavation of the 214,800_ft long tunnel would begin at the Deer Island
shaft and would eventually connect to the Nut Island shaft. The tunnel wo jld ha ’e a
maximum positive slope towards Nut Island. Tunnelled material would be removec
through the Deer Island access shaft. The tunnel would be lined with reinforce:
precast concrete sections.
F.5.3 CRITERIA FOR DETAILED EVALUATION
The tunnelled inter-island conveyance system alternative was evaluated in de:a l
using the set of selection criteria described below.
F.5.3.1 Environmental
Air Emissions Control. Air emissions control qualitatively addresses the pote t1ai
for generating air emissions and odor during conduit construction. This crlterlc
will qualitatively rate impacts as either “Mitigable” or “Not Mitigable”.
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TABLE F.5.c. SUMMARY OF INTER-ISLAND CONVEYANCE MODE SCREENING
Screening Criteria!
Inter-Island Conveyance Mode Tunnel Sunken Tube Pipeline
Marine Ecosystem No Impact Negative Impact Negative Impact
(0) (—) (—)
Tmpacts on Resources No Impact Negative Impact Ncgative Impact
(0) (—) (—)
7’ Disposal of Excavated Material Not Difficult Difficult Difficult
(+) (—) (—)
Constructibility Difficult Difficult Difficult
(—) (—) (—)
Institutional Constraints Possible Definite Definite
(0/—) (—) (—)
Cost Expensive More Expensive More Expensive
(0) (-) (-)
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QUINCY
BAY
NUT
ISLAND
SUNKEN
LEDGE
LONG
ISLAND
TUNNEL
DEER
ISLAND
RAINSFORD
ISLAND
TUNNEL
PEDDOCKS
NIXES
MATE
ISLAND
0.5
0
SOUTH
SYSTEM
0.5
05
SrATUTE MILES
PUMPING
C
STATION
0 0.5
NAUTICAL MILES
SOURCE: MWRA STFP IV, 1987
FR;IJHE I’.5.a. PI’\rN IFW OF UNTEIHSL NI CONVEYANCE SYSTEM \I.TER NATIVE
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mo
I&I
In 0
,mo
-J
I d I 0
200
TYPICAL TUNNEL
CROSS SECTION
SOURCE: MWRA STEP IV , 1987
2000 SGX - - I000 ___ !KX )
u.O ’Z SCALt-FI( t
NEW
HEADWORKS
_- NUT ISLAND SEA BOTTOM
,SEA LEVEL El 105’
RAINSFORD ISLAND
DEER ISLAND-
•SOUTH SYSTEM
PUMP
STATION
ROCK
AJ
t’jO
“0
0
- 0
z00
U
I ,-
I#)
z
I
A-A
-- REINFORCED CONCRETE LINER
INV EL
I’K;I R i ; PICOFU II VIlW 01 IINTIIt-ISI,ATN I) (( )NVI Y NCF SYS’I’IY 1 AL’1’I H ‘ \‘FIVE
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Noise Control. Noise could adversely affect marine biota as well as coastline areas
which are used for commercial or recreational puj’po es. Noise during construction
woula be due to tunnelling as well as occasional drilling and blasting. The
criterion of noise control will quantitatively assess the noise due to conduit
construction and qualitatively assign the construction a rating of “Minor”.
“Moderate” or “Extensive”.
F.5.3.2 Engineering Feasibility
Reliability. This criterion assesses the ability of’ the conduit system to
continuously operate over the expected range of conditions d_ring the life of the
design. Relative ratings were established using measurements of “Rel ableor “Not
Reliable”.
Constructibility. The criterion of constructability assesses the difficulty and
risk associated with constructing the conduit system. Included in this criterion
are adverse impacts of weather and construction technology involved. Construction
risks and difficulties were qualitatively rated as “Minor”, “Moderate” or
“Extensive”.
F.5.3.3 Cost
Present Worth Cost. Present worth cost presents the sum of the costs required to
construct and operate the project as a single investment. This cost includes
capital cost of the project through the year 2020 and is measurea in milliors of
dollars.
Project Cost. Project cost includes the capital cost of constructing facilities,
equipment replacement costs during the planning period and 35 percent to cover
construction contingencies and administrative, engineering plus legal costs.
Project cost is presented in millions of dollars.
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F.5.3. 1 1 Materials Disposal
Disposal of Tunnelled Material. It is anticipated that tunneiled r ater1al w I he
removed through the access shaft on Deer Island and used for site preparation during
construction of the Deer Island wastewater treatment facilities. Disposal of t -e
tunnelled material was rated based on the volume of material to be cisposed a c
degree of difficulty associated with disposal.
F.5.3.5 Institutional
Construction Duration. This criterion examines the relative diff cult of a
specific construction technology based on the expected time required for co pietior
of construction.
Permitting. The number of’ permits required and the relative difficulty in obtaining
these permits for each alternative was assessed. A rating of “Moderate” or
“Extensive” was assigned, reflecting the relative difficulty of perrnittir g
associated with the alternative.
Demand for Unique or Scarce Construction Resources. The relative demand that t}-.e
alternative may put on scarce resources or resources not available in the local area
was assessed. These resources include labor and construction materials which may be
in heavy demand due to other major local construction projects such as corstr c:io
of the Third Harbor Tunnel. The alternative was qualitatively rated as eitr’er
“Moderate” or “Difficult”.
F.5.3.6 Harbor Resources
Protection of Cultural and Historical Resources. The potential to protect areas of
cultural or historical value was assessed for the conduit construc:ior
alternative. Included in this assessment were potential impacts on archaeolog i ar
historic resources such as shipwrecks. A relative rating of “Minor”, “Moderate” o
“Extensive” was assigned to the alternative.
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Water Traffic. Interference with marine traffic as a result of construction will be
examined. Water traffic interference is related to the amount of time which marire
traffic would be disturbed during the construction project due to the tyoe of
construction selected for the project. Measurement of this criterion was made on a
relative basis with “Minor”, “Moderate” or “Extensive” as a rating.
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REFERENCES
Brooks, Norman H., 1987. Seawater Intrusion and Purging in Tunnelled Outfalls - A
Case of Multiple Flow States, (appended to MWRA Secondary Treatment Facil zies
Plan, Volume V, Appendix E).
Massachusetts Coastal Zone Management, June 19? . Map.
Massachusetts Coastal Zone Management, Sept. 1987. Areas of Critical Environmer.ta
Concern. (ACEC).
Massachusetts, Commonwealth of, 1985. Massachusetts Surface Water Quality
Standards, published in Environmental Reporter by the Bureau of Nat onai
Affairs, Inc.
Massachusetts Executive Office of Environmental Affairs, The Technical Advisory
Group for Boston Harbor and Massachusetts Bay, 1986. Study Plan for Basin w1 e
Management of the Boston Harbor/Massachusetts Bay Ecosystem.
Massachusetts Water Resources Authority, 1987. Outfall Siting Assessrrtert Memoraidu.rn
FG3LW Secondary Treatment Facilities Plan.
MWRA, STFP IV, 1987. Secondary Treatment Facilities Plan, Volurr e IV, Inter-Island
Conveyance System.
M 1 dRA, STFP V, 1987. Secondary Treatment Facilities Plan, Volume V, Effluer t
Outfall.
MI4RA, STFP VA, 1987. Secondary Treatment Facilities Plan, Volume V, Appendix A.
Physical Oceanographic Investigations.
MWRA, STFP VD, 1987. Secondary Treatment Facilities Plan, Volume V, Effluent
Outfall, Appendix D, Conceptual Diffuser Design.
MWRA, STFP VE, 1987. Secondary Treatment Facilities Plan, Volume V, Appenci. : E.
Engineering Analysis of Alternative Outfall Systems.
MWRA, STFP VF, 1987. Secondary Treatment Facilities Plan, Volune V, Effi e ’t
Outfall, Appendix F, Onshore Geotechnical Investigations and Geotechn cal Desi i
Criteria.
Metcalf & Eddy, Inc., 1979. Wastewater Engineering: Treatment, Disposal, Reuse.
McGraw-Hill Book Co., New York, 920 pp.
Metropolitan District Commission, June 1982. Nut Island Wastewater Treatment Pia’:
Facilities Planning Project, Phase 1, Site Options Study, VolLn es I anc ii.
prepared by Metcalf & Eddy, Inc.
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Metropolitan District Commission, 198 4. Application for a Waiver of’ Secondary
Treatment for the Nut Island and Deer Island Treatment Plants, preparec b,
Metcalf & Eddy, Inc.
Nahant SWIM, Inc., 1987. The Sapphire Necklace.
Sankey, Greg, 1988. Stone & Webster Engineering Corporation personal communication.
Seberis, Kenneth, Northeastern University, 1987. Personal communication.
U.S. Environmental Protection Agency, 1986. Public Record of Decision on the Final
Environmental Impact Statement for the Massachusetts Water Resource Authority’s
Proposed Siting of Wastewater Treatment Facilities for Boston Harbor.
U.S. Environmental Protection Agency, 1985a. Final Environmental Impact Statement,
Siting of Wastewater Treatment Facilities for Boston Harbor.
U.S. Environmental Protection Agency, Environmental Research Laboratory, 19 3 5D.
Initial Mixing Characteristics of Municipal Ocean Discharges: Vo 1u me II
Computer Programs.
U.S. Environmental Protection Agency, March 29, 1985c. Tentative Decision of the
Regional Administrator on the Revised Application Pursuant to 4O CFR Part 125,
Subpart G.
U.S. Environmental Protection Agency, 1986. Criteria for Water 1986,
EPA L 14O/5_86_OO1.
Wallace, Floyd Associates, Inc., 1986. Boston Harbor Islands State Park, 1986
Master Plan, prepared for Massachusetts Department of’ Environmental Managerient.
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APPENDIX G
REGULATORY CONDITIONS
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APPENDIX C
REGULATORY CONDITIONS
G.1 INTRODUCTION
This appendix provides regulatory information for use as a reference to assist lr
evaluating the feasible alternatives for the major decision areas in the Bos: -.
Harbor Wastewater Conveyance System Supplemental Environmental Impact Staterer:.
The major decision areas are: outfall location; diffuser type; effluent conduit
mode and route; and inter-island conduit mode and route. Numerous Federal, state,
and local laws, regulations, and guidelines could affect the alternat:ves
differently and therefore affect the comparison of alternatives.
This appendix is an overview of the existing regulatory framework for this Draft
SEIS. The areas Of decision are briefly described in Section G.2. In Section G.3
the most recently amended versions of relevant laws, regulations, and guidelines are
surn rnarized. The regulations discussed are cited fully in the text. The cates of
the latest amendments are given in Tables G.5.a and G.5.b.
The applicable regulations and guidelines and their different effects on the areas
of decision are summarized in Tables G.5.a and G.5.b The conclusions address t) e
impact of regulatory and institutional concitioris on the alternatives propose: fc.r
the four areas of decision.
This evaluation of regulatory conditions was done simultaneously with alterra::ves
screening (Appendix F) arid therefore addresses all potential alternatives.
G.2 AREAS OF DECISION
G.2.1 OUTFALL LOCATION
The effluent from the Massachusetts Water Resources Authority (M’ l A) Deer lsarc
wastewater treatment facility will be discharged through an outfall to the ocear
environment east of Deer Island. The location of the discharge will be deterr :re:
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following an evaluation of environmental, engineering, cost, ar.d regulatory fac cr!
(Appendix F). The selected location must be sufficientlY far from shore to a o:z
direct impacts on the shoreline and the quality of the receiving waters.
C .2 .2 EFFLUENT CONVEYANCE MODE AND ROUTE
The alternative methods of’ conveying effluent to the outfall location are a p ce:e
or sunken tube on the sea floor and a deep rock tunnel (Appendix F). The pipe:r
and tube methods require placing the conduit in a covered trench for protect:o.
This method would require dredgang as well as possibly disposal of dredged materla
at a remote locatior.. It could also require blasting of rock to cors:ruct tre
trench.
The second method is a ceep rock t innel. This tunnel would originate f o a
vertical shaft at Deer Island and be constructed in rock by a tunnel boring racr.€
or a comoination of machine and drill and blast techniques at a depth of 2 O to
300 feet below the sea floor. The excavated rock material would be rerDved fro— t e
Deer Island shaft.
The route of the effluent outfall ..ould be dependent on the cor.struct:C rcc€
used. A rock tunnel ouid oe constructed virtually in a s:raag t .ane frc ‘ee
Island to the outfall location with some consade ataor to geote hrical co:i::cs.
A pipeline route would he dependent or batrvretry, environmental, harbor resources.
geotechnical, and engineering factors.
G.2.3 DIFFUSER TYPE
For the tunnel method of effluent conveyance, two diffuser types coud be su::a:ie
(Appendix F). One proposed system would utilize a tunnel and several riser! a c g
the last one mile section of tunnel. A series of vertical riser shafts
(approximately two feet in dian eter) would be drilled from the surface into t -e
tunnel. Once drilled, multi-port caps would be installed to enhance dasperslo of
the effluent. The other diffuser type would originate from a single large vert:ca
snaft drilled into the tunnel. A pipe with a series of diffuser ports ao l: 5€
G-2
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connected to the large vertical shaft and buried in a dredged trench. This r•e: :
would require dredging as well as possible disposal of dredged material at a rer tE
location. It could also require blasting of rock to construct the trench.
For the pipe mode of effluent conveyance only one diffuser type is feasible. Tr. s
consists of a pipe with diffuser ports buried in a dredged trench.
G.2. 1 1 INTER-ISLAND CONVEYANCE MODE AND ROUTE
Consolidation of wastewater treatment at Deer Island will require conveyance of
approximately 360 mgd of South System wastewater from Nut Island to the prcpcse:
South System pump station at Deer Island, a distance of about f:ve r! iles. T .e
inter-island conduit could be constructed by any of three methods: dee rock tu r e.
a cor ’bination marine pipeline and tunnel, or a combination sunker’ tube ar.d t re.
For aiy methoc, a tunnel section is required to cross President Roads beca .ise cf t-e
oceanographic, geotechnical, arc navigational conditions (ApDenclx F).
To construct a tunnel, vertical access shafts would be constructed oi ard at t e
beginning aid erd of the tunrel. These shafts would penetrate into sound rccr
ending about 200 to 300 feet below the surface. At that depth either a tu-nel
boring machine or combilatlor of machire and drill and blast tecr riic.uez c.id
excavate an aDproxlmately 25.000 linear foot tur e1 with a 13 foct iareter.
Approx r ateiy 200,000 cubic yards of tunnel borings would be rer oved fro the access
shaft at Deer Islar.d and used during site preparation for the aste ater trea:et
facility.
The second aiternat ve is an eleven-foot diameter marine pipeline 1LI,300 feet r
length, which would be built between Nut Island and Long Island. The plpeline o..l:
be placed in a dug trench and then backfilled and stone covered for pro:ectio.
tunnel 12,600 feet long, as previously described, would connect Long Island and Deer
Island with vertical access shafts on both Long Island and Deer Isla-:.
Approximately 96,LI00 cubic yards of pipeline and shaft excavates would be rercve:
and require suitable sites for disposal. Approximately 1,500,000 c t c ya-ds of
dredged material would require a suitable disposal site.
G-3
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The final alternative, an eleven foot dianeter sunken tube 114,300 feet i
would be built between Nut Island and Long Islar d. Agaln, a tu nei (12,600 fee:
long) would carry the wastewater on to Deer Island with access shafts or. Long ar
Deer Islands. The fabricated tube would be towed into position over an exca:ate
trench, and sunk into the trench. Trench excavation, stone bedding, backfill. ar.:
cover protection would be similar to that of the pipeline cor,strUC Or.
Approximately 1,500,000 cubic yards of dredged material would require su a e
disposal.
G.3. FEDERAL LAWS AFFECTING AREAS OF DECISION
G.3.1 NATIONAL ENVIRONMENTAL POLICY ACT
The National Environmental Policy Act of 1969 (142 USC 14321_143 147, as are ec)
requires that a detailed Environmental Impact Statement (EIS) be prepares fThr ar:.
proposed rra:or Federal action which is deterrrined to have significart in ac: o the
quality of the human environment. This is a Supplemental EIS (SEIS) which f 1f: s
NEPA’s requirements.
The development of an EIS or an SEIS is controlled by the Council on E v ron e tal
Quality’s Regulations for Implementing the Procedural Provision of t e a:i ai
Environmental Policy Act (140 CFR 1500-1508). The purpose of NPA a d :ts sjppo ::rg
regulations is to er.sure that:
• the probaole environmental effects are identified;
• a reasonable riun ber of alternative actions and their environrrerta r-:a :s
are considered;
• environmental information is available for public understanding and sc ” ..::r :
and
• public and government agency participation is part of the decision proce5s.
All pertinent regulations or permits and their inherent protections must e
disclosed by the EIS, and any subsequent actions must comply. NEPA ooes not pernit
or prohibit any action, but only requires disclosure of envlronmental infor’r.aiC’
ar d public participation in the decision process.
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Subpart E of EPA ’s regulations for implementing NEPA (L O CFR 6) sets fort tne
environmental review procedures for the Wastewater Treatment Constructior Graits
Program under Title II of the Clean Water Act (CW ). EPf is authorized i.rder
CWA, as amended, to provide grant assistance to municipalities for the bu ld ng of
wastewater treatment projects with secondary or more stringent treatment.
The basic elements include preparation of an Environmental Information Docune’ t
(EID) by the Grantee, review of the EID by State and Federal officials, ar a
finding by EPA that the project will have no significant adverse impacts (FNSI) or
that an EIS (or SEIS) is required. The regulations also requlre integrated
consultation throughout the facilities planring process between E? , the State. a d
the grant applicants.
G.3.2 FEDERAL WATER POLLUTION CONTROL ACT
The Federal Water Pollution Cortrol Act (FW?CA) of 1972 as arren:ed by the Cea
Water Act (CW ) of 1977 (33 Usc 1251 et sea.) seeks to restore and main:a: the
chemical, physical, and biological integrity of the Nation’s waters ( O C
101(a)). The FW?CA set a national goal of elimination of discharge of pollutants
into U.S. navigable waters by 1985. An interim goal of water quality w ’ic provides
for the protection anc propagation of’ fish, shellfish, and wildlife arc prcv:ces for
recreation in and on the water was to be achieved by July 1, 1953.
In order to achieve these goals, the Act stipulated that publicly owned treatret
works were to achieve secondary treatment, as defined by the Administrator of tie
EPA by July 1, 1977. The CWA aiso recognizes a need for more stringent techno:.cg.,-
based effluent limitations on discharges into some bodies of water in orcer to
preserve or improve their quality.
Section L 01 of the FWPCA delegates water quality certification to the states.
States must certify that waters of’ the U.S. will not be degraded by any s3ec:f :
discharge (including the discharge of dredged materials) before the discharge can
proceed. EPA is ultimately responsible for erforcing the law’s re uirenents.
G-5
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Section O2 of the FWPCA establishes the National Pollutaflt Discharge E1im:r a:io
Syste i (NPDES). This system is adnin stered by EPb. and requires per 1ts for pc.i :-
source discharge of pollutants into U.S. waters. However, the EPA Ad rir strator ca
authorize a state, which is capable of administering a permit program, to iSSJe
NPDES permits. In Massachusetts the Executive Office of Environmental f ff ai s
(EOEA), Department of Environmental Quality Engineering (DEQE), Division of Wa: r
Pollution Control (DWPC), is authorized to certify and enforce the NPDES perm:tS. as
well as jointly sign them with EPA. However, the ultimate respons:bility hes
EPP to develop, issue, and enforce the NPDES permits in Massachusetts.
The NPDES progra.m regulations define discharge and pollutants broadly e oug :
cover all types of activity and material, except discharges of dredge: or f 1
material. The latter is regulated under Section Zi014 of FWPC .
Section 14024 of the FWPCA regulates the discharge of dredged or fill r ateria1s —:o
U.S. waters and ocean waters inside the territorial sea boundarj. Wate s cf the
U.S. include navigable waters; wetlands; tributaries to navigable waters including
ad)acent wetlands, lakes, and ponds; interstate waters and their tributaries and
adjacent wetlands; and other waters which, if destroyed or degraded, coLld affect
interstate or foreign commerce (U.S. ACOE NED, unoated).
Navigable waters are defifled as waters that are sub)ece to the ebb and fiOh of the
tide and/or are presently used, or have been used in the past, or may be susceptible
for use to transport interstate or foreign commerce A dererm nat o. of
navigability, once made, applies to the entire surface of the waterbody, and is n t
extinguished by later actions or eve.,ts which impede or destroy navigable capac :
(33 CFR 329.14).
Wetlands are defined as areas that are inundated or saturated by surface cr
groundwater at a frequency and duration sufficient to support, and under no: nal
circumstances do support, a prevalence of vegetation typically adapted for life i
saturated soil conditions. Wetlands generally include swamps, marshes, bogs, a.id
similar areas (33 CFR 323.2c).
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Regulating and permitting dredged material disposal under Section L Ol4 of the FW?Ci.
are administered by the U.S. Army Corps of Engineers (U.S. ACOE) and EPA. Per t
applications for dredging or disposal proposed in New England are processed b, the
U.S. ACOE, New England Division, Regulatory Branch, Waltham, Massachusetts.
Regulations for federal projects involving the disposal of dredged material ir
navigable and ocean waters inside the territorial sea boundary are described ifl
33 CFR 209.1115 et seq. and for private projects in 33 CFR 320-330. The territor:al
sea boundary is defined as the area from the high tide mark or the baseline (lir e
across the mouths of bays) to a line three miles offshore of the seawardmost point
of land exposed at mean low water. The regulations require that disposal of credged
materials from Federal projects ta :e place at specified disposal sites. Sites r
navigable waters must be evaluated using guidelines developed by EP? 1 in cor.JLrct:c
with U.S. ACOE. These guidelines are described in 40 CFR 230, Sectioi L0L (:)(1)
Guidelines for the Specification of Disposal sites for Dredged or Pill Material
The funda.rneital precept of the guidelines is that dredged material should not be
discharged into the aquatic ecosystem unless it can be dernorstrated that the
discharge will not have unacceptable adverse impacts (110 CFR 230. (c)). The
guidelines emphasize protection of such special aquatic sites as sanctuaries and
refuges, wetlaids, mud flats, vegetated shallows, coral reefs, and riffle arc pool
complexes ( 0 CER 230.1(d)). The gu del:nes also require investigatiol of all
practical alternatives to aquatic discharge which would lessen the impact or. the
aquatic ecosysten and have no other sigrificant environrrental consecuences. The
guidelines prohioit discharges if they would: cause or contribute to state t.ater
quality standards violation; violate the toxic effluent standards of the NFr:
jeopardize endangered species; adversely impact designated marine sanctuaries: arc
contribute to significant degradation of waters of the U.S., adversely affec::r
human health and welfare, aquatic life and ecosystems, and recreational, aestbet..c.
and economic values (110 CFR 230.10). Details for assessing the potential impacts of
discharges and techniques for minimizing the adverse effects of discharges are a_sc
contained in the guidelines.
U.S. ACOE permits issued under 33 CFR 209 and 33 CFR 320 allow discnarge of oredge:
material at specified sites within navigable waters. Permits must co :iy w tb the
C-?
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above described guidelines developed by EPA and U.S. ACOE. The EP? Ad n stra:c
may deny or withdraw designation of a disposal site, after a publc hea ing s ec.
if discharge of materials will have an unacceptable adverse effect o
water supplies, shellfish beds, fishery areas, wildlife, or recreationa! areas.
Section 303 of the FWPCA requires states to develop water quallty standards as par:
of their water quality managemert system. EPA Guidelines for State and Are3 .. de
Water Quality Management Program Development outline the purpose of state .ate
quality standards. Standards are required to:
• Public ly define the State’s water quality ob)ectlves, and hence fc’rn the
basis for its planning,
• Serve as a basis for determining the NPDES effluent 1imicatic fcr
pollutants which are not specifically addressed in the effluent guidelines C:
for pollutants frozr i..hich the effluent guidelines are not stringent enc. ’;
protect desired uses;
• Serve as a basis for evaluating and modifying Best Managernen: Prac::cer (E P)
for control of nonpoint sources,
• Serve as basis for judgemenc in other water quality rela:ed proc:a s, fc:
exai ple the control of toxic substances; and
• Contain the State’s antideg:adat.ion policy
(EP Gui elines for State ad Areaw:de Water Q . a1it’ a a;ee t Prcz a
Development, Ch. 5: Water Quality S:a :ards, 11/76)
The standards must be reviewed and upoatec once every U-ree yca”s. The a e
quality stardarcs apply to all surface waters of the U.S., terr:toia seas. a-: a
sources of pollutarts.
EPA issued draft final guidelines in September 1987 to provide specific infor: .c
for States and Regions on interpretation of the statutory requirements of 5e ::c
304(1) of the CWA, as amended, and to place the new requirements in context with :-
nationwide program for controlling toxic pollutants and toxicity (Draft F: a
Guidance: Impler ’ entation of Requirements under Section 3014(1) of the Clea Water a
Amended, 9/87).
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The guidance document outlines the new requirements of the Surface Water Toxics
Control Program and identifies the relationship of the new requireme :s to the
ongoing programs. It also provides requirements and guidelines fo” the
identification of waters impaired by Section 307(a) toxic pollutants and other
sources of toxicity, the identification of point sources of impairment, and the
development of individual control strategies (140 CFR (1)). The guidelines
include an implementation schedule of Section 30 14(1) requirements, and s.jrimaries of
state and EPA responsibilities.
G.3.3 RIVERS AND HARBORS ACT OF 1899
The Rivers and Harbors Act of 1899 (33 USC 1401_Lfl3) provides protectic fo
navigation and the navigable capacity of waters of the United States. Se eral
sections of the Act delegate perrr.ittirg authority to different agencies.
Section 10 (33 CFR 322) regilates excavation or deposition of r 1 aterial or crea:io
of obstructions in iavigable waters. Tnis sect ori applies to dredging, d sp sal cf
dredged materials, filling, and constructior of any structures, fixed or floatirg,
which may be navigat o obstructions, or ary other modification of a naviga le a:er
of the Unitea States (U.S. ACOE NED, undated). Section 10 per it:ing is
adn nistered by U.S. ACOE with the cooperation of EPP.
G.3. 1 MARINE PROTECTION, RESEARCH, AND SANCTUARIES ACT
Marine Protection, Research, and Sanc:uar es Act (MPRSA) (33 USC 1Z401 et. se;.), as
amended through 1987 (also kno ..n as the Ocean Dumping Act), regulates dispcsa.
activities in the ocean seaward of the territorial sea boundary. EPA and U.S. ACO
are charged with developing and implementing regulatory programs to ensure tra:
ocean disposal will not adversely affect human health and welfare, arr.en:ties.
marine environment, ecological systerrs, or economic opportunities in the ocean.
Section 102(a) of MPRSA requires EPA to issue permits for the dumping of se.-.a e
sludge and other materials into ocean waters. Section 102(a) charges E? wit-.
developing criteria to use for review of ocean dumping permit applications. The
criteria must address the potential impacts of the ocean dumping on: hu an ealt :
G-9
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fisheries and aquatic resources, and on wildlife, shorelines and beaches; marine
ecosystems; and the potential longevity of the effects. Alternatives to ocean
dumping must also be addressed. Permits will not be issued for du.’ pi’ .g t;:
violates water quality standards.
Section 103 of the MPRSA establishes criteria for the designation of open water
dredged material disposal sites. Actual designation of disposal sites is perfo’ re
by EPA and only designated sites may be used for disposal. U.S. ACCE issues perT:ts
for the transport of dredged materials over waters of the U.S. for disposal at
designated sites. The Evaluation of proposed ocean disposal sites is regulated by
the criteria for the Managenent of Disposal Site for Ocean Duriping (L 0 CFF 22E).
The interim designated disposal site near Boston is the Fo il rea Disposal S :e.
Final designation for the Foul Area Disposal Site is currently under re :e y E -.
U.S. ACOE regulations (33 CFR 320) require compliance with reg.i:.a: ois for areas
designated Marine and/or Estuarine Sanctuaries under Title III of t e t’?FS . T e
Marine Sanctuaries Program is administered by the Office of Coastal Zore Mageet.
National Oceanic and Atmospheric hd inistration (NO h), U.S. Department of Co e ce
(DOC). No federally-listed marine or estuarine sanctuaries are located ir : €
project study area.
G.3.5 COASTAL ZONE MANAGEMENT ACT OF 1972
The Coastal Zone Management Act of 1972 (16 USC 1L151 et seq.) pro ides states
the authority to establish coastal zone management prograirs. Section 307 of t e c:
requires that Federal agencies conducting or supporting projects affec: r’ : ‘e
coastal zone in states with approved coastal zone management programs must coi ’.’
with the program to the maximum extent practicable. The Massachusetts Coasta. :c. - e
Management Program is administered by the Office of Coastal Zone Managemert. T e
program is discussed in greater detail in Section G.LL5. of this append x.
G-iO
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G.3.6 FISH AND WILDLIFE COORDINATION ACT
The Fish and Wildlife Coordination Ac: (16 Usc 661—666, as amended by F l c La.
89-72, 7/9/65) requires consultation with federal agencies on proposed ac::o s
affecting fish and wildlife resources. The implementing regulations, 33 CFR 32D.3.
state that under the Fish and Wildlife Coordination Act Reorganization Pia v-
1970, any Federal Agency which proposes to control or modify any body of water “IL.’st
first consult with the U.S. Fish and Wildlife Service (USFWS), U S. Departn er : of
Interior (DOl), U.S. Department of Commerce, and the National Marine Fisher.ze5
Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), U S
Department of Commerce (DOC), when appropriate, and the appropriate State açe.
exercising administration over the wildlife resources of the affected state.
The goal of the agency cor.sñtation 1! to eliminate, minimize, arid’o r : za :e
adverse impacts to fish and wildlife. Advice from the USFWS ard : e cts
administrators, must be considered in deter ri ng the outfall location, the diffuser
type to be employea, the effluent conveya ce mode aric roi te. and the ir:er- sa:
conveyance mode and route.
G.3.7 ENDANGERED SPECIES ACT OF 1973
The Endangered Species .ct of 1973 (16 USC 1351 et seq., as a rne :ed FL.::c La..
88-237, 6I25i8 4) requires that Federal Agencies actions do no: eopar:ize ti-c
continued existence of er.dangered or threatened species or result i the cestr..c::c
of critical habitat. Two agencies, the DOl arid DOC, administer the Ac:. If tre
USFWS or NMFS determires that a proposed Federal action may affect the cor::’ c:
existence of a listed species the action agency may prepare a biolog ca assess ic :
to assess the project impacts on the species. Consultation under the Endargere:
Species Act for the proposed action is conducted with the USFWS Ecological Sev:
Branch in Concord, NH, and the Habitat Protection Brarch of the NMFS in Gloucester,
MA. Major, unmitigable impacts on an endangered species habitat would effectivel ,
preclude use of certain locations for the effluent outfall, inter-island conai ::. C-
for disposal of dredged material.
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EPA consjlted the IJSFWS and NMFS regarding the potential occurrence of federa.ly
listed threatened or endangered species in the study area. EP? receive: letters
fror FWS and NMFS stating that there are no Federally listed or proposed threatened
or endangered species under their jurisdiction known in the project area
(Attachments 1 and 2). Coordination with the Massachusetts Natural Her:ta e
Program, as suggested by USFWS, is discussed in Section G.Ll.9.
G.3.8 MARINE MA 1AL PROTECTION ACT
The Marine Mammal Protection Act regulates or prohibits the taking of mar e
rnarn als. Tne Act defines taking as to harass, hunt, cap:ure, or kill an z ina:.i.”e
mamjr al (16 USC 1362 (7)). The Act inciuded harassment as part of the cefinitior. of
taking in order to prohibit unintentior:al acts adversely affecting marire
(Beafl, 1977). Construction or operation of the outfall or inter-isiard conc..t. o
the cisposal of dredged material cannot take marine mar’.r als or redtice tre sDecies
ability to maintain optimun sustainable population levels. The Ac : is adr:ristere:
b ’ NMFS.
G.3.9 NATIONAL HISTORIC PRESERVATION ACT OF 1966
The National Fistoric Preservation Act of 1966 (16 USC L 7Oa et. seq.) recu res the:
Federal Agencies cor.sider the irrpac: of projects or: h s:orical arid arc eologca
resources, and avcid unnecessary harm to those resources. Cor.sul:at1o1 w:th Sta:e
Historic Preservation Offices is required to deterrt’ine whether the proposed act:o
will adversely affect properties which are eligible for listing ir the Nat:ona!
Register for Historic Places. Section 106 of the Act estab .ishes requireierts fcr
identification and mitigation of eligible properties. The State Histor::
Preservation Office in Massachusetts is the Massachusetts Historical Preser a: c
Commission. They cooperate with the Massachusetts Board of Underwater Prcheolo :cai
Resources.
36 CFR 800 provides regulations for consultation and states the purpose of
National Historic Preservation Act as requiring Federal agencies, to the
extent possible, to undertake planning to minimize harrr to h stor c resc rCC .
G-12
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G.3.1O FEDERAL LAWS AFFECTING UPLAND DISPOSAL OF DREDGED MATERIAL.
W ule Federal laws do not directly regulate upland d:sposal of dredged matcr aa.
several laws do apply to upland disposal. The Safe Drinking Water Act of 72
(142 USC 300 et seq., as amended by Public Law 99-339, 6/19/86) allows EP to
identify sole source drinking water acquifers for protection. EPA can revie* ar
proposed federally funded projects affecting sole source aquifers, and funds ca rot
be committed until EPA is satisfied that the aquifer will be protected (140 C F
1147). Drinking water contamination from leachate or runoff from dredged materia
disposal facilities is a concern.
The Resource Conserva:ion and Recovery Act of 1976 (RCRA) (142 USC 6905, as are cc
through Public La 99_1499, 10’17/86) regulates the disposal of no -agri u2tura:.
solid and liquid wastes which are not subject to NPDES permits under tne
RCRA applies primarily to hazardous wastes. Section 60014 of the Act re ires t}at
Federal agencies whicn generate solid wastes or permit waste disposal must er s re
compliance with RCF . If dredged material meets the definitions for hazard3Js
materials in 140 CF 261, it must be a sposed of in a licensed hazardous as:e
facility (140 CFR 260,26k). L cersed facilities are all upland. EPA a:m risters t e
RCRA program.
The Solid Waste Disposal Act regñations (140 CER 2L1) prov:de gu:deiines fror E
for the land disposal of nonhazardous solid wastes. Although the Solic as:e
Disposal Act has been completely replaced by RCRA, compliance with the guidelires :r
40 CFR 2141 is still mandatory for Federal agencies and recom.rnendei for State.
regional, and local agencies.
The guidelines require that the hydrology of the disposal site, the chemical a
biological characteristics of the waste, alternative disposal metnods, enviro’rreta_
and health affects, and safety of personnel be considered when determining if .as:e
is acceptable for land disposal (140 CFR 2141.201-1). The guidelines also cff :
requirements and recommendations for the design and operation of disoosa.
facilities. Land disoosal must conform to local and FWPCA water quality star:ards
and applicable Clean Air Act Standards. FWPCA water quality standards are e>p a: e:
in 40 CFR 125 and Federal clean air standards are founo in 140 CFR 50 et se:.
G-13
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Massachusetts water regulations are found in 3114 CM 9 and air regulatiorS ir
310 CMR 7 (as amended through 198€).
The primary considerations of the Solid Waste Disposal Act ( 4O CFR 2141) gu de1 re!
pertaining to dredged material disposal are water quality preservation ano c.d:
control. Land disposal facilities for dredged material would have to cc:r:
leachate and runoff to protect groundwater and use cover material to preveflt o:: .
if necessary.
Beginning in 1988, EPA is scheduled to develop requirements for proh bitio or
treatment of specific materials under the Solid Waste Disposal Act as a ede: ::.
RCRA (hO CFR 268). Dredged rtater als are not generically induced i’ tne l:s: c
materials to be evaluated, but sediments may contain materials to be e a ..ate.
Materials to be evaluated are listed n 140 CFR 268.
G.3.11 EXECUTIVE ORDER NO. 11990: PROTECTION OF WETLANDS
The Executive Oroer No. 11990: Protec: on of Wetlands states that Fe e al agec:es
shall take action to minimize the destruction, loss or deçradaticn of we:lar ds, ard
to preserve and enhance the natural and beneficial values of wetlands ii carryirg
out the agencies’ responsibilities for . . providizg federal . f c
construction and improvements (Executive Order, No. 11990, Section 1(a). 17;.
Agencies are not to provide assistance for new construc:lor located in etla cs
unless no practicable alternative is found by tne head of the agency a d tre ha ’ tc
the wetlands which may result is minimizeD. The public rius: also be gi;e t e
opportunity to review any new construction plar s or proposal.
G.3.12 EXECUTIVE ORDER NO. 11988: FLOODPLAIN MANAGEMENT
As a result of’ Executive Order No. 11988: Floodplain Managenent, Federal agec.es
which finance or assist construction or improvement projects shall (be requires) cc
take action to reduce the risk of flood loss, to minimize the impact of floodr c-
human safety, health and welfare, and to restore and preserve the natural benefic:al
values served by floodplains (Executive Order, No. 11988, Section 1, 1979). Ea:
G-1 1 4
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agency must determine whether or not the proposed action will occur ir t .e
floodplain and what the potential effects are.
Actions must be designed to avoid adverse effects and incompatible developmeit in
floodplains. Agencies must provide for early public review of any plans or
proposals for actions in floodplains (Executive Order No. 115114, Section 2 (t)).
Structures constructed with federal assistance are required to be built in
accordance with the standards and criteria and to be consistent with the .in:e.n: of
these promulgated under the National Flood Insurance Program (Executive Orce ,
No. 11988, Section 3(a), 1979).
GM STATE LAWS AFFECTING AREAS OF DECISION
G.Z . 1 MASSACHUSETTS ENVIRONMENTPJ. POLICY ACT
The Massachusetts Environme’ tal Policy Act (MEP ) (MGL, Ch. 30, Sec. 61-62’r) is
administered by the MEPA Unit of the Executive Office of Environmental f ffairs
(EOEA). The Act requires the preparation of an Environmental Impact Report (EIR) to
determine the environmental impacts of state actions (broadly defined to nclu:
permits, approvals and funding).
Proponents of projects requiring State action submit an Env ronmerta1 Notifica: c
Form (ENF) to the MEPA Unit for review and publication in the Environ . ner : 1
Monitor. The ENF briefly describes the project and its potential irn act. Tr.e
Secretary of EOEI .., after the thirty day comment and review period. iss .es a
certificate statir.g whether the ENF adequately describes the r pacts of
project. If so, the MEPA process ends. If not, a detailed EIR must be prepare:
the proponent according to a scope issued by the Secretary. The EIR process
includes production and agency and public review of a draft and final EIR. No c:- r
state permits can be issued until 60 days after the availability of a final EIR.
Not all State actions require the preparation of an EIR. Some actions are
categorically excluded. On the other nand, projects involving any of the fOll . .i
aspects require the preparation of an EIR:
G- 5
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• dredging or disposal of more than 10,000 cubic yards of material;
• licenses for structural alteration of dams to effect more than 20 percent
increase/decrease in impoundment capacity;
• filling, dredging, constructing, rip-rapping or direct alteration of more
than 500 feet of waterway bank;
• any landfill within a half-mile of a public groundwater supply or within :ne
watershed of a public surface water supply;
• any new nonresidential construction project entailing direct alteration of
more than fifty acres of land;
• any project requiring alteration of ten or more acres of land subject to
Chapter 131, Section 40 of the Wetlands Pro ectiofl Act;
• stream channelization or relocation of two-thousand feet or more;
• new impoundments of one billion gallons or more; and
• sites for disposal of hazardous wastes.
(301 CMR 11.0)
MWRA’S Secondary Treatment Fac lities Plan addresses the MEPA recu re efltS.
G)l.2 WETLANDS PROTECTiON ACT
The Massachusetts Wetlands Protectlon Act (MGL, Ch 131, as a.re ed 1987) a-
regulations (310 CMR 10, as amended through 1987) provide local Conservatiol
Commissions with jurisdiction to regulate filling, dredging, removal, or alteration
of virtually any coastal area, wetland, fresh water body or land su:Ject to f!oodii
or areas adjacent to such lands.
The Act seeks to protect fisheries, land containing shellfish, groundwater, :er
supplies, and wildlife habitat; prevent storm damage and control floocs; and preve-:
pollution. Conservation COmmiSSiOnS review applications and approve or deny pe - i:s
called Orders of Conditions. Applicants or individuals objecting to the findingS of
the Conservation Commission can appeal the decision to the E0E , DEQE, Divisioi of
Wetlands and Waterways Regulations.
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G. 1 L3 CERTIFICATION FOR DREDGING, DREDGED MATERIAL DISPOSAL AND FILLING IN
WATERS
Massachusetts General Laws, Chapter 21, Section 27, as amended 1985, require that
water quality certification be granted by EOEA, DEQE, DWPC for any project dispos rg
of materials in State waters (waters landward of the three mile territorial sea
limit). Water quality certification is charged to the states by the FWPCA.
The Commonwealth must certify that disposal will not degrade waters below present
water quality classifications. Testing of disposal materials is required to
determine if Commonwealth or Federal (FWPCA, Section 1401) standards will t€
violated. Regulations for water quality certificatiofl appear in 3114 C R 9, as
amended 12/31/86.
G 14• 14 MASSACHUSETFS CLEAN WATER ACT
The Massachusetts Clean Water Act (MGL, Ch. 21, Sec. 26-53) is administered by the
EOEP 1 , DEOE, DWPC. The Act regulates water quality through a multi-faceted
regulatory process of water quality standards, effluent limitations, and perr its.
0.14.5 COASTAL ZONE MANAGEMENT PROGRAM
The Massachusetts Coastal Zone Management Program was created by MGL, Chapters 2
and 6A and affects any activity in the coastal zone requiring Federal licenses or
permits or using federal funding. Review of projects by the Massachusetts EOE.,
Coastal Zone Management Office, and determination of consistency with the
Massachusetts Coastal Zone Management Program, is required before Federal licenses.
permits, or funding can be granted. Regulations of the Massachusetts Coastal Zore
Management Program appear in 301 CMR 21, as amended through 11/79.
The Massachusetts Coastal Wetlands Restriction Act (MGL, Ch. 130, Sec. 105) controis
development in significant wetlands resource areas by enacting permanert Orders of
Restrictions for specific wetlands. Orders of Restriction vary in scope but
generally prohibit extensive dredging or filling of specific resource areas. P a:
G-17
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of the restricted wetlands resource areas is ma taine by the EOA, DQ, D : s:c •
of Wetlands and Waterways Regulations. Siice the liSt of restrictec weta :s
changes and deals with individual parcels of land or a s alI scale, coisulta io
with the Division of Wetlands and Waterways Regulations is required on a
site-by-site basis (Barr, 1987).
Similarly, MGL, Ch. 21, Sec. 2, establishes the Area of Critical Enviro’ enta!
Concern Program (ACEC), which for the coastal zone is adrnin stered by the Office of
Coastal Zone Management. The program provides a higher level of protection under
existing state laws for areas of critical environmental concern identified by the
State. The higher restriction levels effectively elirr inate ACECs from cons derat:O
as dredged material disposal sites. The Back River a d Weir River are de.sirated
ACECs located within the study area.
G.’L6 MASSACHUSETTS SURFACE WATER QUALITY STANDARDS AND DISCHARGE PERMITS
Massachusetts EOE , DEQE, Divisior of’ Water Pollutior Control (DWFC) is cLert
re-crafting the State’s surface water quality standards (3114 CM 14, ours ar t to MCL,
Ch. 21, Sec. 27). The Massachusetts Surface Water Q...alizy Starcards des.i’ra:e tne
uses for which the various surface waters of the Commonwealth shall be enharced,
maintained and protected, describe the hater quality criteria required to s sta
the designated uses and maintain existinc wate: quality incl d:n’, hne:e
appropriate, the prohibition of discharges (31 CVE 14.0’). The coastal a rr.ar: e
waters in the study area are Class SA waters, which are designated for the uses c
protection and propagation of fish, other aquatic life and wildlife; for primary a d
secondary contact recreation; and for shellfish harvesting without depura:ior, i .
approved areas (3114CMR 14.03). The Massachusetts surface quality standaras fo
Class SA waters are outlined in Table G.14.a.
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TABLE G . . a. COMMONWEALTH OF MASSACHUSETTS
SURFACE WATER QUALITY STANDARDS FOR CLASS SA WATERS
P4RAMETER CRITERIP
1. Aesthetics All waters shall be free from pollutants in
concentrations or combinations that:
a) Settle to form objectionable deposits;
b) Float as debris, scum, or other matter to
form nuisances;
c) Produce objectionable odor, color, taste.
or turbidity;
d) Result in the dominance of nuisance
species.
2. Radioactive Substances Shall exceed the recommended lin its of
the USEF? National Drinking Water
Regulations.
3. Tainting Substances Shall not be in concentrations or
combinations that produce undesirable flavors
in the ecible portions of aquatic orgar sms.
LI. Color and Turbidity Shall no: be in concentrations or
comDinations that would exceed the
recommencec limlts on the most ser sitive
receiving water use.
5. Suspended Solids Shall not be in concentrations or
combinations that would exceed the
recommended limits on the most sersitive
receiving water use.
6. Suspended anc Settleable Solids Shall not be in concentrations or
combinations that would impair the most
sensitive designated use; none aesthet1ca .
objectionable and none triat would adversely
impact the physical or chemical co positio
of the bottom of benthic data.
7. Oil and Grease The water surface shall be free from floating
oils, oils, grease, and petrochemicals, and
any combinations in the water colurrn or
sediments that are aesthetically
objectionable or deleterious to the biota are
prohibited. For oil and grease of petrole .r
origin the maximum allowable discharge
concentration is 15 mg/l.
8. Nutrients Shall not exceed the site-specific li ts
necessary to control accelerated or cL1tura
eutrophication.
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TABLE G . . a. COMMONWEALTH OF MASSACHUSETTS
SURFACE WATER QUALITY STANDARDS FOR CLASS SA WATERS (Continued)
r’ rr
9. Other Constituents Waters shall be free from pollutants in
concentrations or combinations that:
a) Exceed the recommended limits on the most
sensitive receiving water use;
b) Injure, are tOX1C to, or produce adverse
physiological or behavioral responses jr
humans or aquatic life; or
c) Exceed site—specific safe exposure levels
discharge by bioassay sensitive resident
species.
Coastal ar d Marine Class S4 Waters
The following additional minirr r. criteria are applicable to coastal and marine
waters:
1. Dissolved Oxygen Shall be a minimum of 85 percent f
saturation at water tenpera: ”es abc• e 77°E
(25°C) and shall be a minimum of 6.0 rrg l at
water temperatures of 77°F (25°C) and
below. Natural seasonal and daily variatio’s
above these levels will be maintained.
2. Temperature None except where the increase will not
exceed the recommended limits or the most
sensitive water use.
3. pH Shall be in the range of 6.5-8.5 stanca c
units and not more than 0.2 units oUtSiCC of
the naturally occurring range. Shall be no
changes from background that would irrpair tr.e
most sensitive designated uses.
L Total Coliforrr 3acteria Shall not exceed a median value of 70 MFN p
lOOml and not more than 10 percent of the
samples shall exceed 230 MPN per 100 nil in
any monthly sampling period.
5. Fecal Coliform Bacteria Shall not exceed a median of 1 4 MPN/100 ml
nor shall 10 percent of the samples exceed 53
MPN/100 for a 5—tube, 3 dilution test (or i9
MPN/lOOml for a 3-tube dilution test) in
approved shelifishing areas. Elsewhere Class
B fecal coliform criteria.
Source: Massachusetts Surface Water Quality Standards, MGL Ch. 2 Sec.27, 3 i C
ILO, as amended throug -. 10/83.
G-20
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The proposed criteria for other constituents is clarified for MWRA’s pr000se
discharge by correspondence from Thomas C. McMahon, DW?C to Michael GritzL :. MV
dated May 15, 1987. The DWPC states that Whole Effluent Toxicity Analyses a”:
pollutant specific numerical criteria be used by in its outfall sitirg
procedures. The procedures M’WR are to utilize are outlined below:
• All gold book criteria and any other pollutant—specific criteria utilized
by the Division (DWPC) for aquatic toxicity and human health shall be
consistently met at the Zone of Initial Dilution (ZID); and
• Whole Effluent Toxicity Testing shall show no Acute or Chronic Toxicity at
the edge of the ZID. Compliance will be determined by use of NOAEL (acu:e
and NDEC (chronic) tests.
(DWPC, 1987)
The DWPC goes on to say: If the Authority is unable to meet either the
pollutant-specific criteria or whole effluent toxicity requrements , a Toxics
Reduction Evaluation must be implemented to determine and reduce those poll :ar :s
responsible for failure of the toxics requirements (DWPC, 1987).
With regard to mercur: concentratlols. the DWPC’s policy is that all effl ie :
discharges into Massachusetts Bay rrust have concentrations of the subject
contaminant no greater than the eyisting observed ambient concentrations (Dv F,
1987).
The DW?C assumes delegation from EPA to implement the surface water and groLnd. a:e:
permit program within the Commonwealth, as a result of 31L C 2.0, pursua : to X3.
Ch. 21, Sec. L 3. Regulations regarding the discharges of polluta’ts to surface
waters, outlets of sucn discharges, and any associated treatment works a e
administered by t e DWPC. 31 4 CMR 3.0 contains the regulations for discharges cf
pollutants to surface waters.
G-2 1
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G. L7 WATERWAYS LICENSE AND DREDGING PERMITS
Waterways Licenses and Dredglng Permits are issued by DEQE, Division of Wetlards a—:
Waterways Regulation under MGL, Chapter 91, as amended through 1987. P11 activities
involving dredging and filling in tidelands require permits. Chapter 91 seeks to
protect public rights for use of the tidelands and shore area. Applications fo
permits are evaluated based upon conditions which protect public rights of’ f1sh nE.
fowling (waterfowl hunting), and navigation. Projects must also serve a prope:
public use and comply with the Massachusetts Coastal Zone Managerien: Progazr.
Existing regulations (310 CMR 9, as amended 1979) categorize dredged materials base:
on level of contamination and assign areas where material may be disposed. t eA
regulations for Chapter 91 are being promulgated. -
G. 1 L8 MASSACHUSETI’S DIVISION OF MARINE FISHERIES
The Massachusetts EOEA, Department of Fisheries, Wildlife a d Env roimeital La
Enforcement (DFWELE), DiviSion of Marine Fisheries (DMF), un e MG_, Ch. 130,
Sec. 1 1014, reviews projects which may affect fisheries. The DMF also p o\iaes
advice on reouction, mitigation, or elinlnation of fisher:es impacts. No foriral
permits or approvals are grantec. The DMF also revie .s applicatlois for Federal
Section 1 014 and Section 10 permits under the FWPCA, which are granted by U.S. bCO.
G. 1 L9 NATURAL HERITAGE AND ENDANGERED SPECIES PROGRAM
The Massachusetts EOEA, DFWELE, Natural Heritage aid Endangerec Species Prograrr
(MGL, Chapter 131, Section L ) provides advice to other agencies and reviews Federal
and State applications potentially affecting plant and a i al species that are
endangered, threatened, or of special concern.
EPA also consulted the Massachusetts Natural Heritage Program. The Natural Heritage
Program identified a “Species of Special Concern”, the common tern Sterna hirundc
and an “ecologically significant natural feature”, a coastal heron rookery or Lo—g
Island and Peddocks Island respectively. They go on to say however, that since the
inter—island conduit will be entirely subterranean in the area of these two islands,
these occurrences will not be adversely affected (Attachineit 3).
G-22
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G. . 10 MASSACHUSETTS LAWS AFFECTING UPLAND DISPOSAL OF DREDGE MATERIAL
Upland disposal of dredged material in Massachusetts is regulated by EOEh, DEQE.
DWPC. Under existing Massachusetts regulations (310 CMR 32, as amended through
July 1, 1979; 3114 CMR 5.10, as amended through 10/01/87), upland disposal of’
sediments of marine origin is prohibited where groundwater or surface water may e
affected by leachate or runoff unless sodium chlorides in the sed mer t have beefl
treated so as to pose no threat to groundwater. Limits set on sodium concentra1o
are far below the amount of sodium normally found in marine sediments, and treat - :
to remove sodium and chlorides is prohibitively expensive. This, in most cases.
removes upland disposal as a viable option in Massachusetts (Barr 1987).
G.5 CONCLUSION
Regulatory and institutional factors applicable to the alternative outfa
locations, effluent conduit modes and routes, diffuser types, ard inter-:slaia
conduit modes and routes provide different constraints for the differe t
alternatives. Tables G.5.a and G.5.b summarize the relevant Federal and state lads
and guidelines and their potential impacts on the proposed alternatives.
The regulatory factors which constrain the outfall location are water quality
standards and discharge pern it laws. Local conditions at a specific outfall site
affect the mixing zone. Conditions within a mixing zone determine whether or not a
discharge will meet water quality standards and also discharge perrn:t
requirements. The diffuser and discharge must not impair navigation and therefore
be constructed and sited accordingly. Specific regulated resources, such as
endangered species and mar:ne mammals, must not be jeopardized by the outfa .
location.
Dredging trenches for the diffuser ports or pipeline and disposal of the tur e.
borings will require permits for disposal of the dredged material, s cing :- e
proposed facilities, and the operation of the construction equipment.
The effluent outfall and inter-island conduit siting alternatives and construction
operations that involve a pipeline or sunken tube are also subject to regulatory
G-23
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TANLF. G.S.a FEDERAL lAWS, RFCIPLATIOHS, AND C II II IPLINES AND ThEIR APPLICARII.ITT IS) TIfF. AL1tRNATIVFS
Out I ill filff,,u,’r I II l,.rut Diii l vii liii yr—bland Iand,,ll
fleet al ona 1.4,, at I ‘in Typ e Mini.’ anti Ri , ,, i i’ finite anti R,nut
‘liii’ii, I ‘li’ItI t.’,t
and fit II .,‘.,‘r Tutu ,,.’ i I I p ’ II , ,.’ i.,nn,’ I I’I pelt ne/ ‘.unl .•, ,
l.awa, Regtu I a Ll .,na, an.l C,,t del I .n.a RI .,‘rq I’ll..’ To. ft .: 1,i,,,i .’ I
I) Nailnn,I Fnvlronmentai Policy Act I I I I I I I I
(4? i’si; 41 21—6347, a amende,I,
‘ .0 dR 6, in amended through 9/12/86)
2) Federal Water Pollution Control Art
— sectIon 401 (40 CFR 12), 10/87) X
— aectlnn 402 (60 CFR 122, 4/Ri) I X I I I
— eecttnn 404 (33 CFR 209, 33 CFR 320—330, 49 CFR 230) x x x x
3) Rlver and Harbor Act of 1899 (33 USC 401—413) x x
4) EPA C,,idelinea for Water Quality Management Program I I I I I I I I
I)evelopment Water Quality Standardq (Il/ IS)
5) EPA Guldelinea on Implementation of Requirementa I I I I I I I I
under aec. 30 6(l) of the Clean Water Act
(Draft FInal Guidance, 9/87)
6) MarIne Protection, Reaearch, and Sanctuarlea Act I I I I I
(33 USC 1401 et aeq., aa amended by Public Law 100— 6,
2/4/81; 33 CFR 209, 33 CFR 230)
7) Cnaatal 7one Management Act (l b USC 1351 at aeq., I I I I I I I I
v i amended by Puhlir Law 99—272, 6/7/86)
8) Fiah and Wildlife Coordination Act (l b USC 661—666, 1 I I I I I I I
aa amended by Public Law 89—72, 1/9/63)
9) Endangered Spectea Act (16 USC 1351 at aeq., aa I I I I I I I I
amended by Public Law 88—231, 6/25/84)
10) Marine Mammal Protection Act (lb USC 1361 at aaq., I
as amended by Public Law 98—364, 2/4/87)
II) National Historic Preaerwal ion Act (16 CFR 800) 1 I I I I I I I
12) Safe DrinkinE Water Act (62 USC 300 et aeq., aa I I I I
amended by Public Law 99—339, 6/19/Rh)
I I) Reaourca Conservation and Recovery Act of 1976 1 1 1 1
(62 uSC 6905, as amended by Public I.aw 99—699,
I n/I i/Rh)
16) SnI ld Waste fliaponal Art (40 CFR 241) I I I I
IS) Faer,,lIve Order Nn. 11988 Flnndplaln Management I I S
16) ivrr,,llve order Nn. 11990 Protect Ion ol Wet lands I I I
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I,, .. tnt...,..
TABLP r. .b IIASSACHIJSII1S LAVS• RFCUlATI0NS Alit) GUIDFI. 1NVS AND TIW.IR APPI.ICARII.l1Y Ti) TN ?. AI.TVRNATIVP.c
(liii tat I t)Itfu ,•r III I ... ii (hi! I ill
I ..,. Iy . . . ui,,,I.’ .,i.,l
In s • r—Iqlnu,t
ii •,, iii,
(..n,I,,IV
R •,,l
1. s,,, ,. . I
,,,4
P’,.l LI — 1 ,nrt
1)1 If .,n, .r T,,nn.’’ Pt •. line F,,nn,’ Pt p . I •n . /
S,i,,k.ui Ti.h• /
T ,s, ,n . .I
•.a..q. R . .p..Iat’onn, aid C,iidelinea kl .r ,
Pip..
I) Nic .rh ,,n . .IIq Fnvlrnnmpnt.l Policy Act (310 (MR 10)
2) We LIan ,jq ProtectIon Act (MCI. Ch.l3I S e. 6 0,
aa . .nd.’d through l9R1. 310 CMR 10)
3) CertIfication for Dredging, tlredg.’d Material Illaponal.
and Filling In Waterq (MCI. Ch.7 1 . Sec.21. 316 CKR 9)
6) )ia.qarhuqett, Clean Water Act (MCI. th.2I . an am.nd d
I hrouigh i R5)
5) Coantal 7one Management Progra.
— ronni tency review (MCI. ai.2I4 and 6A, 301 DIR 71)
— Conatnl Wetlanda Reatrtctton Act (MCI. Ch.130 , cec.l0S)
— Area of CritIcal F.nvtronmental Concern Program
(MCI. Ch.2 1 , Sec.2)
6) Maaaachusaettn Surface Wager Quality Standarda and
fllnchnrge Pi’r.ILa (MCI. Ch.2l Sec.21; 316 CMR 4 amended
through 10/B ). re—draft of 314 DIR 4 9130/Ri; 314 DIR 3)
1) Waterway. Licenae and Dredging Permit (Ch.91)
(310 CHR 9)
F’)
i. .fl ) Haaa.chuaett. Diviaton of Marine Fiaherlea project
review (372 CMR i—Il)
9) Natural Heritage Fndangered Species Program
(121 CHR B)
Ii X X X I I
I
I
I
I
I
I
I
I
I
I
I
I
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I
I
I
I
I
K
x
I
K
K
K
X
I
I
I
I
K
K
K
K
K K
I
I
I K
K
K K
I I
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K I I
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constraints because dredging will be needed. Dredging for a pipeline or sunken tube
would also require suitable dredge disposal sites which avoid special resources a
the testing of the dredged materials to ensure that excavation and disposal
activities will not violate water quality standaras. It is likely that the dre g
material from the inter-island conduit alternatives that involve pipelines would riot
be suitable for backfilling. In such a case, the dredge material disposal wo..ld
require additional permits.
The deep rock tunnel alternative, for both the effluent outfall and inter-isla:
conduit, has the fewest regulatory constraints if the tunnel excavates are
uncontaminated. If the material is suitable for use at Deer Island for si:e
preparation or other upland disposal sites there would be no reg.ilat ry
constraints. If the tunflel excavates required ocean disposal howe /er. t-e
appropriate permits would have to be obta nec and a disposal site oes giate .
G-26
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REFERENCES
Barr, B.W., 1987. Dredging Handbook: A Primer for Dredging in the Coastal Zoie of’
Massachusetts. Massachusetts Coastal Zone Management. Boston, Massachuse::S.
Bean, M.J., 1977. The Evolution of National Wildlife Law. Council on Environmental
Quality. Washington, D.C.
DWPC, 1987. Letter to Michael Gritzuk, Massachusetts Water Resources Authority Crc
Thomas C. McMahon, Executive Office of Environmental Affairs, Departrrier.t cf
Environmental Quality Engineering, Division of Water Pollution Control, Re:
MWRA Outfall Siting, Compliance with Massachusetts Water Quality Standards.
dated April 15, 1987.
U.S. ACOE, undated. Are You Planning Work in a Waterway or Wetland? (pamphlet).
U.S. Army Corps of Engineers, Waltham,’ Massachusetts.
G-27
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APPENDIX G
ATTACHMENT 1
CORRESPONDENCE BETWEEN U.S. EPA, REGION I
AND
U.S. DEPARTMENT OF INTERIOR, FISH AND WILDLIFE SERVICE
G-28
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United States Department of the Interior
FISH AND WILDLIFE SERVICE
400 RALPH PILL MARKETPLACE
22 BRIDGE STREET
CONCORD. NEW HAMPSHIRE 08501-4901
Ms. Gwen S. Ruta, Chief
Environmental Evaluation Section
u.s. Environmental Protection Agency
Region 1
JFK Federal Bldg.
Boston, MassachusettS 02203
Dear Ms. Ruta:
This responds to your request, dated November 9, 1987, for information on the
presence of Federally listed and proposed endangered or threatened species
within the impact area of the proposed Boston Harbor Wastewater Treatment
Plant outfall.
Our review shows that except for occasional transient individuals, no
Federally listed or proposed threatened and endangered species under our
jurisdiction are known to exist in the project area. However, you may wish
to contact the Massachusetts Natural Heritage Program, 100 Cambridge Street,
Boston, Massachusetts, at 6l7—727—9l9 1, for information on state listed
species. No Biological Assessment or further consultation is required with us
under Section 7 of the Endangered Species Act. Should project plans change,
or if additional information on listed or proposed species becomes available,
this determination may be reconsidered.
This response relates only to endangered species under our jurisdiction. It
does not address other legislation or our responsibilities under the Fish and
Wildlife Coordination Act.
A list of Federally designated endangered and threatened species in
Massachusetts is inclosed for your information. Thank you for your
cooperation and please contact Roger Hogan of my staff at 603—225—1 11 if we
can be of further assistance.
Sincerely yours,
Inclosure Gordon E. Beckett
Supervisor
New England Area
G-29
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P ALLY LlS D DA Am T T SPDU. S
SSAc iUSL1TS
Cciivon Nar
FISM :
Scientific Nate
Status
Di stribjtion
Sturgecx , shorthose
R TILES :
Acioenser brevi rostrirn
£ Ocnnecticut River £
Atlantic Ccastal Waters
Turtle, qreen
Turtle, hawksbill*
Turtle, leatherback*
Turtle, loggerhead*
Turtle, Atlantic ridley
Turtle, Plynvuth red-
bellied
BIRDS :
thelonia niydas
£retJY .thelys ricata
DerTTcchelys coriacea
Carett.a caretta
Lecidoche lys k i i
O rysenivs rubriventris banosi
T Oceanic straoaler in
Southern N qland
E Oceanic stragqler in
Southern N land
E Oceanic stmr er resident
T Oceanic simmer resident
E Oceanic stm er resident
E PlyiTcuth & Dukes Cotmties
Esale, bald Haliaeetus leucoceDhalus
Falcon, American Dereqrine Pa lco aerearinus anatt i
Fal , Arctic erearine
Plover, PjDi.nq
Rceeate Tern
Falco rearinus tundrius
tharadrius melodus
Sterna douaallii douaallii
£ fl tire state
E tire state-reestablish-
Ivent to former breedi.nq
range in progress
E b tire state miqratory-no
nesting
T fl t ire state - nestiriq
habitat
E Atlantic st
Ocugar, eastern
Whale, blue
Whale, fjnback
Whale, hun ck*
Whale, right
Whale, sei*
Whale, spex,I *
Felis concolor couguar
Ba laenoDtera nusculus
Ba laenc,otera ohysa lus
Meaartera novaeanaliae
Eubalaena s . (a]]. soecies)
Ba laenootera borealis
Physeter catodon
E Ditire state-may be extinc
E Oceanic
E Oceanic
E Oceanic
E Oceanic
E Oceanic
E Oceanic
I1DSKS :
nall Whorled Poqonia
Isotria wedeoloides
E Hanishire, Essex
C mties
* EsceDt for sea turtle nestinq habitat, crincioal resc sibility for these
soecies is vested with the National Marine Fisheries Service
Rev. 11/9/87
G-30
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APPENDIX G
ATTACHMENT 2
CORRESPONDENCE BETWEEN U.S. EPA, REGION I
U.S. DEPARTMENT OF COMMERCE,
NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION,
NATIONAL MARINE FISHERIES SERVICE
G-3 1
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UNITED STATES DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
NATIONAL MARINE FISHERIES SERVICE
Northeast Region
Habitat Conservation Branch
2 State Fish Pier
Gloucester, MA 01930
February 16, 1988 TPM
Ms. Gwen S. Ruta
U.S. Environmental
Protection Agency
Region I
J.F. Kennedy Federal Building
Boston, MA 02203
Dear Ms. Ruta:
This is in response to your request for information on the
presence of endangered and threatened species in Boston Harbo;
and surrounding waters for inclusion into the Draft Environmental
Impact Statement for the construction and operation of the
Boston Harbor Wastewater Treatment Plant outfall. The National
Marine Fisheries Service (NMFS), Northeast Region (NER) does not
have site specific field data on endangered and threatened
species within Boston Harbor. Endangered species contract work
occurs in areas that are known or thought to be important habitat
(i.e., Long Island Sound for Kemp’s ridleys sea turtles, Cape Cod
Bay and Steliwagon Bank for right and humpback whales).
Opportunistic sighting data from whale watch boats indicates that
endangered whales do not generally occur in Boston Harbor. The
kemp’s ridley sea turtle tends to use inshore embayments,
estuaries, and harbors to feed and could occur within the project
area. However, the NER has not received any sighting reports of
the ridley or other sea turtles within Boston Harbor. In
addition, sea turtle stranding records indicate that no turtles
have come ashore within the project area.
Based on the Secondary Treatment Plans provided to NMFS, we
believe that the proposed activities will not significantly
affect endangered or threatened species that may pass through
the project area. This tentative conclusion is based on the lack
of sightings within the project area and the assumption that the
potential effects from secondary treated wastewater will be less
then primary treatment wastewater.
NMFS, NER does not have information on sea birds. Possible
sources of information on sea birds are Bob Prescott,
Massachusetts Audubon Society, Welifleet, HA 02663, (617) 349-
2615 and Hike Payne, Hanomet Bird Observatory, Box 936, Manomet.
/1
G-32
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HA 02345, (617) 224—6521. Mr. Payne may also have some
information on the presence of seals within the project area.
Please contact Tracey Mckenzie at FTS 838-6258 if you require
additional information and for further consultation on this
project.
Sincerely,
Tom Blgford, Chief
Habitat Conservation Branch
G-33
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APPENDIX G
ATTACHMENT 3
CORRESPONDENCE BETWEEN U.S. EPA, REGION I
AND
MASSACHUSETTS NATURAL HERITAGE PROGRAM
G-3 1 4
-------
Massachusetts
Natural Heritage
Program
19 February 1988
Ms. Gwen Ruta
Environmental Evaluation Section
US EPA
Region I
J.F. Kennedy Federal Building
Boston, MA 02203-2211
Re Deer and Nut Islands
MWRA project
Boston
Dear Ms Ruta:
Thank you for contacting the Massachusetts Natural Heritage Program
regarding rare species and ecologically significant natural communities and
features in the vicnity of the proposed conveyance systems from Nut
Island to Deer Island and Deer Island to the outfall.
At this time, we are aware of several occurrences of rare species in the
area of the conveyance system between Nut Island and Deer Island. We
have a record of a common tern colony (S erna hu -undo) on Long Island
and a coastal heron rookery on Peddocks Island. The common tern is listed
as a “Species of Special Concernu in Massachusetts. The heron rookery is
an “ecologically significant natural feature.” Since the conveyance system
will be entirely subterranean in the area of these two islands, we feel
these occurrences will not be adversely affected. This determination is
limited to the on-site Impacts only and does not consider the off—site
Impacts, such as disposal of excavated materials. It is our understanding
that we will have an opportunity to review these other aspects of the
project when they are considered later.
If project plans change, or if additional fieldwork and research results in
an update of our database, this evaluation may require additional
consideration.
Do not hesitate to contact me if you have any further questions.
Sincerely,
Jay Copeland
Environmental Reviewer
JC/jc : ER/EPA/BOSTON
G- 35
Division of Fisheries and Wildlife 100 Cambridge Street, Boston, Mass. 02202 (617) 727-3160,-3151
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APPENDIX H
OPERATIONAL RELIABILITY
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APPENDIX H
OPERATIONAL RELIABILITY
H. 1 INTRODUCTION
The purpose of this appendix is to review the recommended secondary treatment plant
(MWRA, STFP III, 1987) and determine its operational reliability. For the MWRA
Secondary Treatment Facilities Plan (STFP), the concept of reliability was viewed as
enhancing the overall integrity of the wastewater treatment system. For the
secondary treatment plant, stress was placed on the need for a design which could,
even with anticipated power outages, variable loading and mechanical failure,
produce an effluent that consistently satisfied the National Pollution Discharge
Elimination System (NPDES) permit. In this appendix, probable failure scenarios of
the treatment process are considered. The backup systems provided are evaluated to
determine their adequacy. The quality of the effluent produced during the various
operating scenarios is determined. A comparison of the consequences when the
effluent produced during the scenarios is discharged through the various outfall
alternatives is presented in the appropriate sections of Chapters 14 and 5 of’ this
Draft SEIS.
H. 1.1 RECOMMENDED PLAN
The recommended plan for the MWRA secondary treatment plant is a pure oxygen
activated sludge process with stacked primary and secondary clarifiers. A detailed
description of the recommended plan for the secondary treatment plant is given in
the MWRA STFP (MWRA, STFP III, 1987). Briefly, the major components of the
wastewater treatment facilities include:
Preliminary Treatment
Screening and grit removal at existing North System remote headworks,
which includes Chelsea Creek, Ward Street, and Columbus Park
Headworks;
Screening at Winthrop Terminal;
H-i
-------
• Additional grit removal for North System flows at new grit removal
facilities on Deer Island; and
• Screening and grit removal of the South System flow at new Nut Island
Headworks.
Wastewater Influent Pumping
• Modification and/or replacement of existing pumps at the North Main
Pumping Station, located on Deer Island;
• Modification and replacement of existing pumps at the Winthrop
Terminal; and
• Pumping of the South System flow at anew South System Pumping Station
located on Deer Island.
Primary Treatment
• Beginning in 1995, primary treatment up to a peak flow rate of
1,270 mgd in four batteries of stacked rectangular clarifiers,
arranged two clarifiers high; and
• Fine screening of primary effluent, using traveling water screens, for
flows in excess of 1,080 rngd, which will receive primary treatment
only. Fine screening of effluent will occur after secondary
facilities are online.
Secondary Treatment
Beginning in mid-1999, secondary treatment of up to a peak flow rate
of 1,080 nigd. The secondary treatment process will include anaerobic
selector basins, oxygen-supplied aeration basins, and four batteries
of stacked rectangular clarifiers, arranged two clarifiers high; and
Oxygen to the aeration basins will be provided by two 300-ton per day
cryogenic oxygen generators.
Disinfection
Disinfection of the effluent using barge—delivered sodium hypochlorite
in chlorine contact basins; and
Dechlorination, if required, will be provided using sodium
metabisulfite.
A schematic illustrating the order of the treatment processes is shown on
Figure H.1.a.
1 1-2
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SOURCE MWRA. STFP III. 1987
FIGURE IL1.a. SChEMATIC OF RECOMMENDED MWRA TREATMENT FACILITIES
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Operating scenarios for the treatment plant were considered from the influent
pumping stations on Deer Island to the effluent from the chlorine contact
chambers. A site layout for the recommended Deer Island facilities is shown in
Figure H.1.b.
The stacked clarifier concept has been used widely in Japan for the past 13 years
but has not yet been constructed in the United States. The Japanese plants range in
size from design peak flows of 16 mgd to 717 mgd. Based on information gathered
concerning the removal effectiveness of the stacked clarifiers (MWRA, STFP hIM,
1987), there is apparently no difference between the conventional unstacked
clarifiers used throughout the United States and the Japanese stacked clarifiers.
Data provided indicates effluent suspended solids in the range of 3 to 1Z mg/i at
average overflow rates of 360 to 860 gpd/ft 2 for the secondary clarifiers. The
recommended plan provides for effluent suspended solids in the 15 to 20 mg/i range
at average overflow rates of 750 gpd/ft 2 for the secondary ciarifiers. These
overflow rates are on the higher end of the Japanese overflow rates range.
H.1.2 OPERATION DURING CONSTRUCTION
The construction of the secondary treatment plant is to be completed in several
phases over a period of approximately 12 years (MWRA, STFP VII, 1987). The existing
primary treatment plant will continue to operate during the construction of new
primary treatment facilities. The full flow to the new primary treatment facilities
is scheduled to begin in December 1995. Temporary disinfection facilities will be
used during the period from 1995 to 1997 when the new primary treatment facilities
alone are online. Primary treatment will be provided until the completion of the
secondary treatment facilities. Full flow to the recommended secondary treatment
facilities is scheduled for mid-1999.
H. 1.3 FLOWS TO TREATMENT PLANT
The design flows to the new treatment facilities were estimated for the STFP (MWRA,
STFP III, 1987). Table H.1.a shows the flow to the plant during low groundwater
and high groundwater periods in the design year 2020. The maximum flow rate of
H-
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LEGEND
$ GRIT IW4 E40
B PRINARY OPEBAflONS BI.*OINO
3 SOU 4 SYSTEM PUMPINO STATiON
4 PRIMARY SPIJTTTR BOB
S EIECTR A$ECHN4ICIM Roos40
• GRIT FACLITV tTYP(: B)
7 PRIMARY ODOR CONTRO (TYP CF 2)
PRIMARY CLARIFIER BATTERY A
PRIMARY CLARIFIER BATTERY S
PRIMARY CLARIFIER BATTERY C
PRIMARY CLARIfiER BATTERY 0
CRVOOEPC TACUTY TYPOF 2)
COMPRESSOR SUE 0.40
LIQUID OrVGEN STORM3B
PRIMARY SC ENS40
SECONDARY SP J1TEN SOB
SECONDARY ooc CONTRQ. ( I V , CF 2)
ANAEROBIC SELECTOR BASIN A
ANAEROBIC SELECTOR BASINS
ANAEROBIC SELECTOR BASIN C
ANAEROBIC SELECTOR BASIN 0
AER.AflON BASIN BArTEMY A
AINATIC 4 BASIN BAtTERY S
AERATION BASIN BATTERY C
AERATION BASIN BATTERY 0
SECONDARY OPERATICF StADS
SECONOARY SLUOGE PUMP STAT1OP
SODIUM I4YPOCIt ORITE STOPM
SOOII.RI 14E?ABISIJEIOE STORAOB
OI5*IFECTK 4 BASIE
OUTFAlL 54&I1’
POTABLE WATER 1* 1 . 4
CEMETERY MARKER
SECONDARY CLARIFIER SATTBWV A
SECONDARY CLARIFIER BATTERY S
SECONDARY CLARIFIER BATTERY C
SECONDARY CLARIFIER BATTERY 0
GATE HOUSE
EL ECTRICRI S(SYAflONS
POWER FACuTIES
01E3€L STORIGE )TYPOF B)
NcRfl4 MAIN PUMPING STAflON
wINfl4ROP TERMINIM
DRY STORACE
vEIACLE MAINTENANCI
UAINT ENANCEIWAR EJ4 0U 31
LABORATORY
AOUIP40TRAflON S.*0 140
PIERS
BL*flI4AO DOCKS
P(SIOU*& PRIXESSINO
S
S
I,
I,
I i
‘3
IA
‘ 3
‘S
I,
‘ 5
‘A
20
2$
22
23
24
23
2 5
B,
25
2IE
30
3’
32
33
I I
‘3
‘S
3’
3.
3.
40
4 $
42
.3
a.
IS
IS
47
Is
a.
So
St
FiGURE 11.1 .b. RECOMMENDED MWRA TREATMENT FACILITIES
‘4
U)
c . • -
• ,oóno’•
‘S S SD’
140 ,
SOURCE: MWRA. STFP III. 1987
600
0
60
SCALE IN FEET
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TABLE H. l.a DESIGN YEAR 2020 FLOWS TO TREATMENT PLAJIT
Low Groundwater
High Groundwater
Average
Maximum
Average
Maximum
Day
Day
Storm
Day
Day
Storm
Flow, mgd 390
600
1,150
670
950
1,270
1,270 mgd was determined based on the total capacity of the existing interceptor
system. The new primary treatment facilities are designed to treat up to 1,270 mgd
of wastewater. The new secondary treatment facilities are designed to treat up to
1,080 mgd. During peak flow periods, up to 190 mgd of primary treated effluent are
mixed with 1,080 mgd of secondary treated effluent prior to disinfection and then
discharged.
H.2 PROBABLE OPERATING SCENARIOS
The existing primary treatment plant at Deer Island has had a history of unreliable
service. The design of the recommended secondary treatment plant must be
operational and reliable under situations of mechanical failure, power outages, and
variable loadings. purpose of this section is to review the recommended
treatment plant, as well as its operation during the construction phases, and
determine what operating scenarios are likely to occur if various types of failures
were to occur. The level of redundancy of equipment and tanks are evaluated to
determine if adequate standby equipment is available when mechanical failures
occur. The power sources to be used to provide electricity to the plant are also
evaluated.
The EPA published Technical Bulletin: Design Criteria for Mechanical, Electric, and
Fluid System and Components Reliability in order to establish “minimum standards of
reliability for mechanical, electric, and fluid systems and components”. (USEPA,
19714) By publishing the document, the U.S. EPA wanted to ensure that treatment
plants will be designed to operate effectively day in and day out and produce an
effluent that consistently satisfies water quality standards. The sections below
review the design features of the recommended plan in terms of its operational
reliability and how they compare with the EPA guidelines.
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11.2.1 REDUNDANCY
The provision of standby equipment and tanks is important in ensuring treatment
plant reliability. Adequate redundancy should be available to allow for mechanical
failure or routine maintenance to occur without impacting the treatment efficiency
of the plant.
A thorough review of the standby provisions for the treatment process equipment and
tankage was undertaken. As discussed below, the recommended plan provides adequate
standby equipment and tanks for all the treatment processes. Some examples of the
amount of redundancy provided are discussed below. Table H.2.a presents a summary
of the equipment and processes used during wastewater treatment and the number of
standby units provided during peak operation of the treatment processes. For
primary treatment, peak flow is 1270 mgd and for secondary treatment, peak flow is
1080 mgd.
H.2.1.1 Mechanical Equipment
The EPA requires as a minimum that every set of pumps that perform the same function
have a backup pump, but that one standby pum n serve as a backup to more than one
set of pumps. The recommended plan provides every set of pumps with at least one
backup unit.
For other mechanical units that provide a complete process, more than adequate
redundancy has also been provided. As an example, the cryogenic oxygen generation
system, which provides oxygen to the aeration basins, includes two full—size units,
thus providing one hundred percent redundancy. In addition, the liquid oxygen (LOX)
storage tank capacity of 1000 tons would provide more than 3 days oxygen supply with
both generators out of service.
H —i
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TABLE H .2. a SUNMARY OF RECOMMENDED TREATMENT PLANT PROCESSES
AT DEER ISLAND,
PROVISION FOR STANDBY UNITS 1
Standby
Redundancy
PRELIMINARY TREATMENT (Grit Removal Facility)
Number of Batteries 2
Centrifugal Grit Chambers
Total Number of’ Units per Battery 8
Number of Standby Units 2(2) 33%
Grit Slurry Pumps
Total Number of Units 32
Number of Standby Units 16 100%
Cyclone Grit Concentrations
Total Number of Units 10
Number of Standby Units 67%
Grit Washers
Total Number of’ Units 10
Number of Standby Units 3
PRIMARY TREATMENT
Stacked Rectangular Primary Clarifiers
Number of Batteries
Total Number of Stacked Sets per Battery 2i4
Number of Stacked Sets Required at Peak Flow 21
Number of Standby Stacked Sets 3
Aerated Inf’luent Channel
Number per Primary Clarifier Battery 1
Total Number of’ Blowers per Battery 2
Number of Standby Units 1 100%
Sludge Pumps
Total Number of Pumps 80
Number of Standby Pumps 32 67%
H-8
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TABLE H.2.a (Continued). SUMMARY OF RECOMMENDED TREATMENT PLANT PROCESSES
AT DEER ISLAND,
PROVISION FOR STANDBY UNITS 1
Standby
Redundancy
Scum Pumps
Total Number of Pumps 8
Number of Standby Pumps 14 100%
Traveling Screens (for up to 190 mgd of
Primary Effluent)
Total Number of Spray Water Pumps 2
Number of Standby Units 1 100%
Total Number of Refuse Pumps 2
Number of Standby Units 1 100%
SECONDARY TREATMENT
Anaerobic Selector Basins
Number of Batteries 14
Number of Compartments per Battery L I
Total Number of Mechanical Mixers
(2 Mixers per Compartment) 32
Aerated Influent Channel
Number of Channels per Anaerobic
Selector Battery 1
Total Number of Blowers per Battery 2
Number of Standby Units per Battery 1 100%
Aeration Basins
Number of Batteries 14
Number of Trains per Batteries 3
Number of Stages per Train L I
Total number of Purge Blowers per Battery 2
Number of Standby Units per Battery 1 100%
Cryogenic Oxygen Generation
Total Number of Units 2
Number of Standby Units 1 100%
Total Number of Compressors 14
Number of Units, 100 Percent Capacity 2
Number of Units, 70 Percent Capacity 2 100%
LOX Storage 1000 çns
Total Number of Cooling Water Pumps
Number of Standby Units 2 100%
H-9
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TABLE H .2. a (Continued). SUMMARY OF RECOMMENDED TREATMENT PLANT PROCESSES
AT DEER ISLAND,
PROVISION FOR STANDBY UNITS 1
Standby
Redundancy
Stacked Rectangular Secondary Clarifiers
Number of Batteries LI
Total Number of Stacked Sets per Battery 36
Number of Stacked Sets Required at Peak Flows 32
Number of Standby Stacked Sets LI 12%
Aerated Influent Channel
Total Number of Blowers per Battery 2
Number of Standby Units per Battery 1 100%
Return Activated Sludge Pumps
Total Number of Pumps 20
Number of Standby Pumps 8 67%
Waste Activated Sludge Pumps
Total Number of Pumps 20
Number of Standby Pumps 8 100%
Scum Pumps
Total Number of’ Pumps 16
Number of Standby Pumps 8 100%
DISINFECTION
Number of Chlorine Contact Tanks ii
Number of Storage Tanks 3
Capacity of tanks, each 250,000 gal.
Total Number of Metering Pumps 13 ,
Number of Standby Pumps 3 9) 30%
Total Number of Dechlorination Metering Pumps 18
Number of Standby Pumps LI 28%
1. Adapted from MWRA, STFP III, J, 1987.
2. One standby unit per battery is provided for a total of 2 standby units.
3. One standby unit per system for a total of 2 standby units.
14• There would be 3 standby pumps during the primary treatment construction
phase. Once secondary treatment facilities are receiving full flow, 6 pumps
would be standby pumps.
H-b
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More than adequate redundancy has been provided for the mechanical systems to
eliminate the operating scenario of one piece of equipment or process failing and
causing a disruption in the wastewater treatment process, assuming that equipment
requiring repair or maintenance is expeditiously put back into an operational
mode. The reliability of the various treatment processes could be reduced if long
periods elapsed before the equipment was repaired and other equipment used for the
same process were to breakdown, consequently reducing the total number of standby
units available. Prompt repair and maintenance of equipment is needed to ensure the
reliability of the treatment plant.
H.2.1.2 Tanks
The recommended plan also provides more than adequate standby tankage for the
primary and secondary clarifiers, as shown on Table H.2.a. For primary treatment,
EPA requires that at least 50 percent of the total design capacity be provided when
the unit having the largest flow capacity is out of service. For the secondary
clarifiers, at least 75 percent of the total design capacity must be available when
the largest capacity unit is out of service. The recommended plan satisfies both
requirements.
From 12 to 114 percent standby tank capacity is available for use during time periods
when maintenance of the tanks is required. However, as stated in the above section,
maintenance or repair of a tank must be completed expeditiously. A reduction in the
reliability of’ the clarifiers could result if the downtime of a tank were
prolonged. If prompt repair or maintenance of the tanks is completed, then more
than adequate numbers of standby tanks are provided for the primary and secondary
clarifiers.
H.2.1.3 Disinfection System
Disinfection requirements are greater for an effluent from a primary treatment
system than for an effluent from a secondary treatment system. Table H.2.b presents
the sodium hypochiorite demands for the primary and secondary treatment phases of
operation.
H-il
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TABLE H.2.b DAILY DEMAND FOR PURCHASED SODIUM HYPOCHLORITE
Low Groundwater High Groundwater
Max. Day Max .Day
Ave. Day
Storm Ave. Day
Flow, mgd
(yr 1999) 1)
377
592
1,150
657
9L 7
1,270
PRIMARY EFFLUENT
10
15
12
8
11
12
Dosage
Cl (mg/L)
lbs of Cl
31,200
63,900
106,600
1t7,600
88,600
122,Z OO
Gallons of
15% Sodium
Hypochiorite
31,200
63,900
106,600
L 7,60O
88,600
122,Z OO
SECONDARY PLANT
EFFLUENT
600
1,150
670
950
1,270
Flow, mgd
(yr 2020)(1)
390
Dosage
Cl(mg/L)
3
6
8
3
6
8
lbs of’ Cl
9,U00
25,600
71,000
17,900
148,300
81,600
Gallons of
15% Sodium
Hypochiorite
9,400
25,600
71,000
17,900
148,300
81,600
1. Flows taken from separate
Source: Adapted from MWRA,
tables
STFP III,
from same
1987.
source (MWRA,
STFP III,
1987).
H-12
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For the five year period when the secondary treatment facilities are being
constructed, the wastewater will receive primary treatment only. The disinfection
system, the on-island receiving area, and the onsite storage area are designed for
primary treatment requirements. Approximately eight days of storage of the sodium
hypochlorite (NaOC1) is available onsite based on maximum daily demands during high
groundwater periods, with approximately 15 days of storage available during average
day high groundwater periods. During average flow conditions three of the thirteen
metering pumps, which feed the NaOCL to the chlorine contact chamber, are backup
pumps. The amount of storage and the number of the backup metering pumps provide
adequate standby redundancy during the primary treatment phase.
During the primary treatment phase, an anaerobic selector basin will be used as an
interim chlorine contact chamber. While adequate amounts of NaOCL will be available
and an adequate feeder system will be provided, inadequate disinfection could result
due to shortened chlorine contact detention time during the period of primary
treatment only. Also, the basic configuration of the selector basin may not be
optimum for chlorination during peak flow conditions. This possibility is discussed
further in Section H.2. 1 .1.
Once the secondary treatment facilities are receiving full flow, the demands for
NaOCL to provide disinfection will be reduced. However, the same amount of storage
volume will be available, providing 15 days of storage for maximum day demands
during high groundwater periods during secondary treatment. Also, fewer metering
pumps will be required, allowing more pumps to be in a standby role. Therefore, the
disinfection facilities for secondary treatment should be very reliable.
H.2.2 POWER
Adequate levels of power supply are essential to the operational reliability of the
treatment plant. As stated in the EPA Technical Bulletin, power sources must be
provided by two separate and independent sources of electric power, such as two
separate utility substations or from a single substation and an onsite generator in
order to provide reliable power. The two separate power sources must be provided at
all times to all vital or essential facilities at the capacity required during peak
periods.
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The estimated electric power requirements for various phases of construction and
plant operation are presented in Table H.2.c. The recommended plan to meet these
requirements include 5 installations of a combination of temporary and permanent
power sources. The recommended plan has been developed in detail (MWRA, STFP III,
H, 1987) and is described briefly below.
H.2.2.1 Recomended Plan
To provide sufficient and reliable power for the construction and operation of the
treatment facilities, power will be supplied in four phases as listed in the
Facilities Plan (MWRA, STFP III, 1987), and provided below:
Install a temporary power supply cable by 1990 or sooner. Provide 15 Mw of
immediate power through Massachusetts Electric Company (MEC0) from its
Metcalf Square Substation in Winthrop.
Install a 115 kv, 70 Mw permanent feeder from Boston Edison Company’s
(BEC0) K .:reet substation in South Boston by January 1992. Placing the
feeder in service requires the installation of a 115 kv to 13.8 kv
substation on Deer Island.
Install an on-island 25,700 kw combined cycle power plant by January 1995
to provide additional capacity for peak shaving and provide protection
against catastrophic failure of the off—site power sources. This
additional capacity combined with the soon-to-be in . . alled fast track
capacity, will result in an installed on—site capacity of 37,700 kw.
Install the second Boston Edison 115 kv, 70 Mw permanent feeder by January
1995. This feeder will originate from BECo’s Chelsea substation.
The two 115 kv feeder cables from South Boston and Chelsea provide the two separate
off—site power sources as required by the EPA Technical Bulletin (USEPA, 19711). No
on-site generation facilities would be required. However, it was determined that
additional on-site generating capacity would be economically beneficial as well as
provide protection against total off-site power failure.
As part of the recommended plan, the electrical power distribution system
provides redundancy which makes power supply to all equipment more reliable. The
H-i 4
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tAILK I I. 2.c PRELIMiNARY POWEK NFEOS UP SEQ)NDARY TREATMENT FACILITIES PLAN
Cumulative
Cumulative
Description of
Average
load
Cumulative
average
Peak
load
Cumulative
peak
installed
capacity
secure
capacity
Cumulativç
shortfall’ 1
Year power
needs
period (kW)
load (kW)
period (kW) load
(kW)
(ku)
(kW)
(kW)
1986 One electrified influent pump 1,500 1,500 3,500 2,800
Basic power usage 650 _________ 650 _________ _________ _________ ________
2,150 2,150 3,500 2,800 0
1988 Electrification of four
additional influent pumps and
Winthrop terminal pumps 2,500 _________ 7,200 _________ 12,000 6,000 _________
4,650 9,350 15,500 8,800 550
1990 Construction power 10,000 _________ 15,000 _________ _________ _________ _________
14,650 24,350 15,500 8,800 15,550
1991 Piers, primary sludge
dewatering, and basic power 4,000 ________ 4,500 ________ ________ ________ ________
18,650 28,850 15,500 8,800 20,050
1995 Primary treatment and basic
power usage 7,800 9,400
Electrification of five
in! luent pumps. Winthrop
terminal pumps and South System
flows 4,100 17,700
Air emissions control 500 1,250
Enterprise engines retired —3,500 —2,800
Construction power —7,000 _________ —12,000 _________ _________ _________ _________
24,050 45,200 12,000 6,000 39,200
1999 Secondary facilities and
basic power usage 13,500 19,400
Additional air emissions
control 250 625
Sludge process 2,000 2,000
Construction power —3,000 __________ —3,000 __________ __________ ___________ __________
36,800 64,225 12,000 6,000 58,225
1. Secure capacity is that capacity which because it is provided from two separate sources is considered to be totally reliable in accordance
with EPA technical criteria (USEPA, 1974).
SOURCE: MWRA, STFP lii, 1987.
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distribution of power to the unit substation and from the unit substations to the
motor control centers is a redundant system. In the event of failure of any
switchgear, transformer or line feeder, power would be transferred to the available
redundant line. No treatment process or equipment would have a period of’ downtime
due to lack of power. The redundant power distribution system adds to the
reliability of the overall treatment system.
H.2.2.2 Essential Power Requirements
The power requirements for the entire operation of the treatment plant and the
phases of construction are presented in Table H.2.c. The power requirements were
further evaluated to determine what power needs were considered essential to the
operation of the treatment facilities. Essential power needs are defined as the
power sources to treatment facilities that, if electrical interruption should occur
to the various processes or equipment, would cause an unacceptable effluent to be
discharged or could present danger to personnel health and safety (MWRA, STFP IIIH,
1987). Table H.2.d presents the total essential power needs of the wastewater
treatment facilities during the various phases of construction and when secondary
treatment facilities are online.
As stated above, a total of’ 37,700 kw would be available onsite in the event of
catastrophic failure of’ both offsite power sources. The 37,700 kw of power includes
the 25,700 kw combined cycle power plant and 12,000 kw of cumulative installed
capacity as shown in Table H.2.d. In the event of offsite power failure, some
reduction of treatment would result. For the period when interim primary treatment
is online, adequate onsite power would be available to provide the 21,050 kw to all
essential facilities during average flow conditions. However, during peak flow
condition, a shortfall of 3,700 kw would result, causing some reduction in the
primary treatment process. When the secondary treatment facilities are online,
adequate onsite power is available to provide the 2L1,300 kw required for average
flow conditions. However, a shortfall of 7,325 kw would result during peak flow
conditions.
Catastrophic failure of offsite power source would result in less than complete
wastewater treatment during peak flow periods. The operating condition of onsite
H- 16
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Description of
Essential
average
load
TABLE H. 2.d ESSENTIAL POWER REQIJIREHENTS (’ )
Cumulative Essential Cumulative
essential Peak essential
average load peak
Cumulative
installed
capacity
Cumulative
secure
capacity( 2
Cumulative
essential
shortfall
Year power
needs
period (kW)
load (kW)
period (kW)
load (kW)
(kW)
(ku)
(kW)
1986 One electrified influent 1,500 1,500 3,500 2,800
pump
Basic power usage 650 ________ 650 ________ ________ ________ ________
2,150 2,150 3,500 2,800 0
1988 Electrification of four
influent pumps (additional)
and Winthrop terminal pumps 2,500 ______ 6,400 ______ 12,000 6,000 _______
4,650 8,550 15,500 8,800 0
1990 Construction power 10,000 _______ 15,000 _______ 0 0 _______
14,6S0 23,550 15,500 8,800 14,750
1991 Primary sludge—dewatering, 1,000 _______ 1,500 _______ 0 0 _______
piers and basic power 15,650 25,050 15,500 8,800 16,250
1995 Primary treatment and basic 7,800 9,400
power usage
Electrification of five influent 4,100 17,700
pumps, Winthrop terminal pumps
and South System flows
-1
Enterprise engines retired —3,500 —2,800
Air emissions control 500 1,250
Disinfection (NaOC1 purchased) 0 0
Construction power —7,000 _______ —12,000 _______ _______ ________ _______
21,050 41,400 12,000 6,000 35,400
1999 Secondary facilities and basic 6,000 6,000
power usage
Additional air emissions control 250 625
Sludge processing 0 0
Disinfection (NaOC1 purchased) (3) (3)
Construction power —3,000 _______ —3,000 _______ _______ ________ _______
Totals 24,300 45,025 12,000 6,000 39,025
1. Essential power is that power required to operate those plant operations which, if interrupted, would result in unacceptable discharges
and/or could present danger to personnel health and safety.
2. Secure capacity is that capacity which, because it is provided from two separate sources, is considered to be totally reliable in accordance
with EPA criterion. (IJSEPA, 1974).
3. Included In Basic Power.
4. Ftgiireq do not include 25,700 kw thst will be available in January 1995 from the combined cycle power plant.
Source: MWRA, STFP III, H, 1987.
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power only being provided is expected to occur very infrequently, perhaps only once
or twice over the life of the treatment plant. However, the operating scenarios for
periods when onsite power only is provided is considered in Section H.2.L$.
H.2.3 OTHER CONSIDERATIONS
Other factors which could disrupt the operation of the treatment plant include labor
strikes, extreme weather conditions and possible biological process upsets.
Personnel going on strike and possibly affecting the operation of the treatment
-plant include MWRA treatment plant operators, truckers responsible for delivering
chemicals to the barge locations and barge operators responsible for deliveries to
Deer Island.
Extreme weather conditions, such as a blizzard or hurricane, could cause a
disruption at the plant, from destruction of’ facilities to delays in barge
deliveries. The frequency or duration of extreme weather conditions can not be
predicted but will undoubtedly occur.
The biological treatment process of the pure oxygen activated sludge treatment plant
is susceptible to upsets when some pollutants are present in excessive amounts in
the influent. Heavy metals in particular can be inhibitory to the biological
organisms in the activated sludge process (WPCF, 1977). Table H.2.e presents the
pollutant concentration limits at which the biological treatment process may begin
to be inhibited and the expected average influent concentrations at the treatment
plant. The only pollutant exceeding the lower limit concentrations is zinc.
The influent concentration of zinc is 0.22 mg/i compared to inhibitory concentration
limits of 0.08 to 10 mg/l. Assuming a 140 percent removal rate in the primary
treatment phase, as presented later in this appendix, the influent concentration of’
zinc to the secondary treatment facilities, where the biological treatment process
occurs; is 0.13 mg/i. This is on the very low end of the inhibitory range and
should not cause process upsets. However, industrial pretreatment programs could
reduce the amount of zinc in the influent and remove the possiblity of a biological
process upset.
H- 18
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TABLE H.2.e COMPARISON OF POLLUTANT INHIBITORY CONCENTRATION
Pollutant
Threshold In
Concentrati
mg/i
hibj. çry
on
Projected Average
Influent Concentration (2),
mg/i
Arsenic
0.1
0.0014
Boron
0.5 to
100
0.39
Cadmium
10 to
10
0.002
Chromium
50
0.02
Copper
1.0
0.10
Cyanide
0.1 to
5
0.028
Lead
0.1
0.017
Mercury
0.1 to
5.0
0.001
Nickel
1.0 to
2.5
0.020
Silver
5
0.0014
Zinc
0.08 to
10
0.22
Phenol
200
0.016
1. Source: WPCF, 1977.
2. Based on average annual wastewater flow of L180 mgd for year 2020
(MWRA, STFP III, 1987).
H- 19
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The considerations of labor strikes, extreme weather conditions, and biological
process upset are factors which could result in the treatment plant producing a less
than secondary treatment effluent. While not viewed as probable operating
scenarios, these factors could impact the operation of the treatment plant.
H.2. 1 1 OPERATING SCENARIOS CONSIDERED
Based on the review of the various components of the recommended treatment plant,
probable operating scenarios that are likely to occur during the life of the plant
were developed. These scenarios were developed based on historical data of other
plants and engineering experience. -
H.2.l4.1 Primary Treatment Phase
Two operating scenarios are discussed in this section. The first is the normal
operating mode of wastewater receiving primary treatment. The second is wastewater
receiving primary treatment with less than adequate disinfection due to the use of
anaerobic selector basins as the contact basins. Based on the review of the
recommended plan and knowledge of likely failures that occur at treatment plants,
these two operating scenarios are the only ct na’ios considered probable to occur
during the primary treatment periods of operation.
In the event that offsite power failure occurs, adequate 37,700 kw of onsite power
will be available to provide all essential primary treatment facilities with power
during the majority of flow conditions. Primary treatment will be able to be
provided in the same manner as if offsite power were online. The infrequency of
catastrophic offsite power outages and slight shortfall of cumulative power during
peak flow conditions eliminates this operating scenario from consideration.
The new primary treatment facilities are scheduled to accept full primary flow in
December 1995 with the secondary treatment facilities accepting full flow in mid
1999. For a period of approximately four years, the normal operating procedure will
be for wastewater to receive preliminary treatment, primary treatment and
disinfection at Deer Island.
H -20
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The primary treatment system will include temporary disinfection facilities. Based
on review of the construction schedule (MWRA, STFP VII, 1987), it is assumed that
the permanent facilities for sodium hypochlorite storage, the on-island berthing
area and pier, and the chemical feed system will be constructed by 1995.
Construction of the disinfection facilities is needed to ensure that temporary
disinfection can be provided to the primary effluent in 1995. The temporary
disinfection facilities will use the anaerobic selector basins as temporary chlorine
contact chambers. Due to its site location, the permanent chlorine contact chambers
will be constructed during the secondary treatment facilities construction phase,
and will not be operational until November 1997.
The interim disinfection facilities are discussed briefly (MWRA, STFP III, 1987).
The STFP recommendations include using eight of the anaerobic selector basins as
chlorine contact chambers during the two to three year period when temporary
disinfection facilities will be required. During the primary treatment period,
eight minutes of detention time at a peak flow of 1270 mgd is available with
1,800 ft. of discharge conduit leading to the outfall providing more contact time.
This would provide the minimum required detention time of fifteen minutes. Because
of the nature of the temporary chlorine contact chamber for the primary treatment
period, short circuiting could occur, resulting in less than adequate ‘islnfection
of the primary effluent. Short circuiting may occur where flow passes through a
portion of the theoretical contact tank volume, resulting in a shorter than design
contact time. The effective detention time may be reduced due to short circuiting,
or inadequate mixing of the chlorine could result. The impact on the effluent in
this situation is discussed in Section H.3.3.1.
H.2.it.2 Secondary Treatment Phase
The amount of redundancy provided for processes throughout the secondary treatment
plant eliminates the scenarios of failure of one process effecting the quality of
H-2 1
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the treatment provided. Based on the review of the recommended plan, three
operating scenarios are considered for the period after full flow to the secondary
treatment facilities begins in mid 1999. The scenarios under consideration include
normal operation of the plant and the expected operation if an offsite power failure
were to occur. The normal operating mode of secondary treatment of’ up to 1080 mgd
of wastewater is considered. Also during normal operating conditions, secondary
treatment of 1080 mgd mixed with up to 190 mgd of wastewater receiving primary
treatment and fine screening can be expected and is considered. During major
offsite power outages, primary treated effluent flowing through secondary treatment
facilities without receiving treatment, with disinfection being provided, is the
third operational scenario considered.
The design of the treatment plant provides primary treatment of wastewater up to
1270 mgd and secondary treatment of flows up to 1080 rngd. During peak periods, up
to 190 mgd of flow will receive primary treatment and effluent fine screening only,
with 1080 mgd receiving secondary treatment. The primary treated effluent will be
mixed prior to disinfection with the secondary treated effluent. This mixed
effluent is expected only during peak flow periods and will have effluent
concentrations slightly greater than that of full secondary treatment.
As stated earlier, the on-island power generation cdpacity at times of’ off-site
power outages is 37,700 kw. As shown on Table H.2.d, adequate power is available
on—island to provide essential power to primary treatment facilities during average
flow conditions and probably to secondary treatment facilities during average flow
conditions. However, the most likely scenario to occur in the event of offsite
power failure is to provide primary treatment during all flow conditions, and allow
the primary treated effluent to flow through the secondary treatment facilities
without receiving treatment, with disinfection being provided prior to discharging
to the outfall. Additional settling of the primary effluent solids could occur as
the effluent flowed through the secondary treatment facilities. The settled solids
would be removed once power was restored to the secondary facilities. Other
facilities that would be provided standby power include influent pumping,
preliminary treatment, disinfection, sludge processing, and critical lighting and
ventilation.
H-22
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H.3 EFFLUENT CHARACTERISTICS
The purpose of this section is to review the effluent characteristics of the
recommended treatment plant and to determine the effluent characteristics for the
various operating scenarios discussed in the previous sections.
The quality of the effluent from a treatment plant depends upon the effectiveness of’
the treatment processes to adequately remove or reduce the pollutants found in the
influent wastewater. The pollutants found in wastewater can be divided into the
categories of conventional and non-conventional pollutants. The conventional
pollutants of concern consist of Biochemical Oxygen Demand (BOD) and Total Suspended
Solids (TSS). Non—conventional pollutants consist of compounds listed as EPA
Priority Pollutants and on the EPA Hazardous Substance List. The removal efficiency
of the pollutants depends upon the amount and type of treatment available.
Conventional pollutant removal rates are guided by the limitations established in
the NPDES permit. Non-conventional pollutant removal rates are estimated during the
planning stages of a treatment plant and can be refined during a pilot plant
study. However, actual removal rates of non-conventional pollutants can only be
verified through influent and effluent sampling programs once the treatment plant is
online.
The estimated removal rates of a treatment process are input to the evaluation of
alternative outfall locations. For this reason, a review of the expected levels of
removal for conventional and non-conventional pollutants for the recommended
secondary treatment plant are provided below. Consideration is also given to the
construction period when only the new primary treatment facilities are online.
H.3. 1 CONVENTIONAL POLLUTANTS
For the MWRA secondary treatment plant, the NPDES permit establishes removal
requirements for conventional pollutants. The NPDES permit limits both BOD and TSS
in the effluent from the secondary treatment plant to an average monthly
concentration of 30 mg/i, an average weekly concentration of 115 mg/i and a maximum
daily concentration of 50 mg/l. These limits for conventional pollutants are used
in determining the size of the process tanks and equipment for the treatment plant.
H-23
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The estimated plant performance for conventional pollutants during the primary
treatment phase as reproduced from the STFP is presented on Table H.3.a.
Restrictions for primary treatment plant effluent are not included in the NPDES
permit. The removal efficiency of the primary treatment process will continue to
affect the up to 190 mgd of the plant effluent when peak flow conditions occur once
the secondary treatment facilities are online.
Once the secondary treatment facilities are online, the concentrations of
conventional pollutants as estimated in the STFP are shown on Tables H.3.b and
H.3.c. As the tables indicate, the permit requirements for maximum daily
concentrations are expected to be satisfied during all flow conditions.
TABLE H.3.a YEAR 1999, PROJECTED PRIMARY EFFLUENT
CONVENTIONAL POLLUTANTS
Low
Groundwater
High
Groundwater
Average
Maximum
Average
Maximum
Day
Day
Storm
Day
Day
Storm
Flow, mgd
377
592
1,150
657
9147
1,270
BOD
lb/day
380,000
782,000
1,013,000
1410,000
8140,000
1,026,000
rng/L
121
158
106
75
106
97
Percent Removed
36
32
23
31
27
22
TSS
lb/day
211,000
1428,000
838,000
222,000
556,000
882,000
mg/L
67
87
87
141
70
83
Percent Removed
60
60
143
58
148
140
Source: MWRA, STFP III, 1987.
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TABLE H.3.b
YEAR 2020, PROJECTED PRIMARY EFFLUENT
CONVENTIONAL POLLUTANTS
Low Groundwater
High Groundwater
Average
Maximum
Average Maximum
Day
Day
Storm
Day
Day
Storm
Influent
Flow, mgd
390
600
1,150
670
950
1,270
BOD, ib/d
570,000
1,1140,000
1,305,000
570,000
1,1140,000
1,305,000
TSS, lb/d
515,000
1,080,000
1,1480,000
515,000
1,080,000
1,1480,000
Primary Effluent
Flow, mgd
To Secondary Treatment
390
600
1,080
670
950
1,080
To Discharge
0
0
70
0
0
190
Total
390
600
1,150
670
950
1,270
BOD
To Secondary Treatment
lb/day
1408,000
826,000
9114,000
1433,000
886,000
960,000
mg/i
125
165
101
77
112
107
To Discharge
lb/day
-
—
67,000
—
—
1J46,500
TSS
To Secondary Treatment
lb/day
227,000
1470,000
791,000
238,000
596,000
828,000
mg/i
70
914
88
143
75
92
To Discharge
lb/day
—
—
50,000
-
—
ii 1,ioo
Values taken from source table did not agree with values presented on Table H.3.c.
Highest values on source tables were used to give most conservative effluent
loadings.
Source: MWRA, STFP III, 1987.
H-25
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TABLE H.3. c PROJECTED PLANT EFFLUENT
CONVENTIONAL POLLUTANTS,
YEAR 2020
Low
Groundwater
High
Groundwater
Average
Maximum
Average
Maximum
Day
Day
Storm
Day
Day
Storm
Plant Effluent
Flow, mgd
Secondary Component 390 600 1,080 670 950 1,080
Primary Component 0 0 70 0 0 190
Total 390 600 1,150 670 950 1,270
BOD
Secondary Component, ib/d i48,800 203,500 360,300 111,800 320,300 360,300
Primary Component, ib/d 0 0 67,000(1) 0 0 1146,500
Total, ib/d 148,800 203,500 1427,300(1) 111,800 320,300 506,800
mg/i 15 141 115 20 110 118
Percent Removed 91 81 67 79 70 61
TSS
Secondary Component, lb/d 148,800 203,500 360,300 111,800 320,300 360,300
Primary Component, lb/d 0 0 50,000(1) 0 0 111,100
Total, lb/d 148,800 203,500 1110,300(1) 111,800 320,300 1171,1400
mg/i 15 141 143 20 140 1411
Percent Removed 90 80 72 79 68 68
1. Values taken from source table did not agree with values presented on
Table H.3.b. Highest values on source tables were used to give most
conservative effluent loadings.
Source: MWRA, STFP III, 1987.
H-26
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The extremely high peak flows and loads that the recommended treatment plant will be
required to treat as a result of high I/I and partially combined sewer systems
results in a highly stressed system under peak flow and load conditions. Due to
space constraints, the pure oxygen activated sludge plant will be flow and load
stressed at peak day loadings. The STFP projects a drop in treatment efficiency
into the 145 mg/l BOD, 145 mg/i TSS range. A fuller understanding of stressed plant
performance would be available if a pilot plant was operated in the near future to
better characterize effluent performance in regard to all pollutants and establish
clearer evidence of the operational reliability that can be expected.
11.3.2 NON-CONVENTIONAL POLLUTANTS
Non-conventional pollutants are defined as pollutants listed as EPA Priority
Pollutants and on the EPA Hazardous Substance List. These pollutants can be toxic
in excessive concentrations. The EPA categorizes these pollutants as metals
including cyanide, acid and base neutral organics, volatile organics, and pesticides
and PCB’s.
Non-conventional pollutants are evaluated to determine what concentrations are
discharged to the environment. Some portion of the non-conventional pollutants are
removed from the wastewater by air stripping or biological oxidation, but a large
percentage of the total amount of non—conventional pollutants passes through the
treatment process and is discharged to the environment with the effluent or removed
with primary and secondary sludge. For this appendix, only the portion of the
pollutants that is discharged in the plant effluent is considered.
H.3.2.1 Influent Loadings
A sampling program was conducted for the STFP to determine influent loadings of all
pollutants (MWRA, STFP IIIB, 1987). The sampling program was conducted during an
approximate one month period in Fall 1986 and an approximate one month period during
Spring 1987. The average influent loading values that were estimated using the
results of the sampling program are the database used to determine the effluent
concentrations for the various treatment plant operating scenarios. No pesticides
or PCB’s were detected during the sampling program conducted for the Facilities
H-27
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Plan. However, during previous sampling that was conducted for other studies on
Boston Harbor, some pesticides and PCB’s were detected. These pollutants, aldrin,
DDT, heptachlor, dieldrin, and PCB, are included in the effluent characteristics
analysis. Table H.3.d presents the existing, average projected, and maximum
projected loadings for the non-conventional pollutants.
H.3.2.2 Removal Rates
Several studies have been completed to determine the ability of treatment plants to
treat or remove toxic pollutants. Removal rates based on various sampling programs
at a variety of treatment plants have been established by each study. The treatment
plants included in these studies varied greatly in size, influent constituents,
treatment process, and in some cases sampling techniques and laboratory testing
procedures. Treatment plant removal may vary based on water chemistry, pH levels,
influent concentrations and the design of the treatment process. The documented
removal rates therefore vary accordingly.
During the Facilities Plan, a review of data sources for removal rates was completed
and estimates for the recommended plan were calculated. For this appendix, a
thor ,‘ review of the data sources was also completed. Comparisons of the removal
rates estimated by the various data sources for both primary and secondary treatment
with those estimated during the STFP are included on Tables H.1 through H.8
presented in the back of this appendix. Table H.3.e provides a comparison of the
removal rates estimated for the Facilities Plan with the estimates developed for
this Draft SEIS based on the review of the data sources.
For some of the non-conventional pollutants, no information on removal rates during
wastewater treatment processes exist. For the Facilities Plan, if no information
existed for a particular compound, a similar chemical compound having a removal rate
was found. It was then assumed that the two compounds would have the same removal
efficiencies. Therefore, a percent removal was given to all pollutants for
secondary treatment in the STFP. If no information was found during the data search
completed for this appendix on removal rates for a particular compound, it is stated
as such on Table H.3.e and the MWRA estimated removal rate is used when determining
effluent concentration in the next section.
H-28
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TABLE H.3.d INFLUENT LOADINGS OF
NON—CONVENTIONAL POLLUTANTS
Projected
Projected
Existing
Average
Maximum
Influent
Loads,
Influe
Loads,
Influent
Loads,
Pollutant ibid
ib/d
ib/d
METALS INCLUDING CYANIDE
Antimony 10.8 16.2 23.1
Arsenic 6.0 7.6 12.3
Boron 1261.2 1570.5 7655.6
Cadmium 7.1 8.4 14.8
Chromium 75.8 88.5 157.14
Copper 3115.1 399.8 639.3
Cyanide, Total 53.9 112.0 169.8
Lead 49.9 69.5 130.2
Mercury L$.1 5.0 17.5
Molybdenum 17.1 21.3 117.2
Nickel 66.0 79.1 149.8
Selenium 35.2 53.3 153.9
Silver 15.5 18.0 26.8
Zinc 738.8 866.2 28L 10.,1
ACID BASE NEUTRALS
Phenol 54.0 611.2 128.7
Benzyl Alcohol 69.3 86.3 1117.8
1,2—Dichiorobenzene 65.1 711.8 128.4
2-Methyiphenol 71.0 88.14 1311.0
L l—Methylphenoi 61.2 76.3 1311.0
Benzoic Acid 269.4 335.5 681.5
Naphthalene 45.3 52.5 118.2
2-Methylnaphthalene 119.6 61.8 128.2
2, 1 I,5-Trichlorophenol 3119.0 1101.0 621.1
Dimethyl Phthalate 69.6 80.2 1214.8
Diethyl Phthaiate 57.1 67.3 125.1
N-Nitro-sodiphenyiaxnine 69.3 86.3 135.3
Di-N-butyl Phthalate 57.9 68.11 129.5
Butyl benzyl Phthalate 54.0 63.7 120.5
Bis (2-ethyihexyl) Phthalate 67.8 78.3 1211.14
Di-N-octyi Phthalate 57.0 65.8 115.2
Fiorene 16.5
H-29
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TABLE H.3.d INFLUENT LOADINGS OF
NON-CONVENTIONAL POLLUTANTS (Continued)
Projected
Projected
Existing
Average
Maximum
Influent
Loads,
Infiue9
Loads,
Influent
Loads,
Pollutant
ibid
ib/d
ib/d
VOLATILE ORGANICS
514.3
62.3
106.8
Bromomethane
Methylene Chloride
1014.7
120.3
293.3
Acetone
337.1
1419.7
1088.6
Carbon Disulfide
27.5
314.3
53.1
Trans—i ,2-Dichloroethylene
Chloroform
25.6
17.6
29.9
22.3
148.1
142.8
2-Butanone
82.5
102.8
211.8
1,1,1—Trichioroethane
141.8
149.7
92.1
Trichioroethylene
36.2
143.6
90.0
Benzene
12.5
16.5
22.6
LI-Methyl—2-Pentanone
614.7
80.5
139.7
Tetrachloroethylene
147.14
61.7
1314.0
1 ,1,2,2-Tetrachloroethane
29.14
3 14.3
149.3
Toluene
60.8
71.3
160.9
Chlorobenzene
28.0
33.8
52.2
Ethylbenzene
28.8
33.14
63.7
Styrene
30.1
37.5
55.7
Total Xyiene
85.9
107.0
255.0
PESTICIDES AND PCB
3.2
14.0
PCB
Aidrin
0.7
1.0
DDT
0.2
0.2
Heptachior
0.8
0.8
Dieldrin
0.1
0.1
1. For year 2020.
Source: Adapted from MWRA, STFP V, 1987.
H-30
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TABLE H.3.e COMPARISON OF REMOVAL EFFICIENCIES OF
NON-CONVENTIONAL POLLUTANTS
MWRA Revised
Recommended Plan Treatment Treatment Removal
Treatment Removal Efficiency, Efficiency Maximum
Removal Efficiency, Percent Flow Condition,
Percent Percent (2)
Pollutant Primary Secondary Primary Secondary
METALS INCLUDING CYANIDE
Antimony 30 60 NA 1 60 50
Arsenic* 25 50 NA 50 140
Boron 2 5 NA NA(1) NA(1)
Cadmium* 15 50 15 50 140
Chromium* 140 76 27 70 60
Copper* 35 82 25 80 70
Cyanide 10 60 20 60 50
Lead* 146 57 50 80 70
Mercury* 22 75 25 80 70
Molybdenum 10 50 NA NA NA
Nickel* 15 32 15 35 30
Selenium* 10 50 NA 50 140
Silver* 30 90 20 90 80
140 76 31 80 70
ACID BASE NEUTRALS
Phenol 20 95 8 95 75
Benzyl Alcohol NA(1) 90 NA(1) NA(1) NA(1)
1,2-Dichlorobenzerie NA 90 NA 90 70
2—Methylphenol NA 90 NA NA NA
L4. Methylphenol NA 90 NA NA NA
Benzoic Acid NA 90 NA NA NA
Naphthalene 0 95 20 95 75
2-Methylnaphthalene NA 90 NA NA NA
2, 1 4,5-Trichlorophenol NA 90 NA NA NA
Dimethyl Phthalate 214 95 NA 95 75
Diethyl Phthalate 0 90 0 95 75
N-Nitrosodiphenylainine NA 69 NA NA NA
Di-N-butyl Phthalate 0 90 20 90 70
Butylbenzyl Phthalate* 0 95 50 90 70
Bis(2-ethylhexyl)
Phthalate* 0 90 0 60 50
Di-n-octyl Phthalate’ 0 90 NA 80 70
Florene* 0 90 NA NA NA
H-3 1
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TABLE H.3.e COMPARISON OF REMOVAL EFFICIENCIES
NON-CONVENTIONAL POLLUTANTS
(Continued)
MWRA Revised
Recommended Plan Treatment Treatment Removal
Treatment Removal Efficiency, Efficiency Maximum
Removal Efficiency, Percent Flow Condition,
Percent Percent
Pollutant Primary Secondary Primary Secondary
VOLATILE ORGAN ICS
Bromomethane* NA(1) 95 NA(1) 95 75
Methylene Chloride* 0 95 0 50 110
Acetone NA 95 NA 95 75
Carbon Disulfide NA 95 NA 95 75
Trans—1,2-Dichloroethene 36 90 36 90 70
Chloroform* NA 90 iLl 60 50
2-Butanone NA 90 NA NA(1) NA(1)
1,1,1—Trichioroethane 1 10 95 110 90 70
Trichloroethene* 20 95 20 90 70
Benzene* 0 95 25 90 70
L l -Methyl -2-Pentanone NA 90 NA NA NA
Tetrachloroethene* 0 90 L I 80 70
1,1,2,2—Tetrachioroethane NA 90 NA NA NA
ioiuene 0 90 3 95 75
Chlorobenzene NA 90 NA 90 70
Ethylbenzene* 0 95 13 90 70
Styrene* 0 90 NA 90 70
Total Xylene NA 95 NA 95 75
PESTICIDES AND PCB
PCB 0 92 NA(1) 92 70
Aldrin* 0 90 NA 90 70
DDT* 0 90 NA NA(1) NA(1)
Heptachlor* 10 90 NA NA NA
Dieldrin* 0 90 NA NA NA
1. NA represents no information available.
2. Maximum flow condition is 1,270 mgd during the periods of high groundwater.
* Compound is on Chemicals of Concern List (MWRA, STFP V, A, 1987). The
compound’s effluent concentration is considered to be of possible concern.
H-32
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Removal rates for the worst case storm event effluent occurring during high
groundwater periods are also estimated. Removal rates for the peak flow condition
of storm flow with high groundwater are more conservative than for secondary
treatment. The quality of the secondary effluent will deteriorate under maximum
storm flow conditions from 15 mg/i BOD and 15 mg/l TSS on average into the 1W to L 5
mg/l range for both pollutants at peaks flow of up to 1270 mgd. Non-conventional
pollutant removal rates can also be expected to drop off from the 90 to 95 percent
removal ranges. For pollutants that are removed by attachment or adsorption onto
the mixed liquor suspended solids, a removal rate of 70 to 75 percent may be
expected. For this reason, pollutant removal efficiencies are considered for the
peak flow condition and have been determined to be somewhat less than secondary
treatment. These removal rates are used in Section H.3.3 when calculating effluent
characteristics of the operating scenarios.
H.3.2.3 Sensitivity Analysis
For most non-conventional pollutants, the removal rates determined for the STFP and
the removal rates estimated for this appendix were similar. However, a sensitivity
analysis was completed to determine the impact of the revised removal rates on the
findings used in the STFP for initial dilution of the pollutant at v ’ “r u.. outfall
site alternatives.
The incremental increase for each removal rate, as determined for this appendix, was
used to compare the concentration of the pollutant at initial dilution to the
Criterion Maximum Concentration, Criterion Continuous Concentration, and the
Carcinogenicity Criteria used in evaluating the impact of the pollutant
concentration for each of the outfall alternatives (MWRA, STFP V, A, 1987). The
results of the sensitivity analysis found that the revised removal rates had no
impact on a pollutant concentration exceeding any criteria requirement, except as
previously determined in the STFP. For this reason, the removal rates determined
during the Facilities Plan will be used to determine the effluent concentrations for
each of the operating scenarios under consideration.
During the evaluation of non-conventional pollutant concentrations completed during
the STFP, a list of chemicals of concern was developed. This list included
H-33
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pollutants which may have concentrations that could be close to exceeding
established criteria. Pollutants not identified on the list were found to have
concentrations that are well below the criteria limits. For these reasons, only
those pollutants identified as chemicals of concern are evaluated when calculating
effluent concentrations for the various operating scenarios.
H.3.3 PROBABLE OPERATING SCENARIOS EFFLUENT CHARACTERISTICS
The effluent characteristics of the probable failure operating scenarios, which were
previously presented in Section H.2.L , are discussed below. As stated previously,
removal efficiencies estimated during the STFP are used to calculate effluent
concentrations. Also, only chemicals of concern are included in the effluent
concentration calculations, as previously discussed in Section H.3.2.3.
H.3.3.1 Primary Treatment Phase
As discussed previously, the probable operating scenarios for the five year period
when primary treatment only will be provided are full primary treatment and primary
treatment with less than adequate disinfection.
The conventional pollutant characteristics for primary treated effluent for the year
1999 are shown on Table H.3.f for both low groundwater and high groundwater
periods. The non-conventional pollutant characteristics of the effluent are
presented on Table H.3.g for average loading conditions and average flow of 377 mgd
and Table H.3.h for maximum loading conditions and peak flow conditions of 1270
mgd. No information was available for removal rates of’ primary treatment for many
of the non-conventional pollutants. Zero percent removal was assumed to present a
worst case situation if no information was available.
The effluent concentrations of the conventional and non-conventional pollutants
remain the same as for primary treatment only for the operating scenario of primary
treatment with less than adequate disinfection. However, an increase in the level
of bacteria and pathogens would result. The NPDES permit requires that the average
H- 31
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TABLE H.3.f YEAR 1999, PROJECTED PRIMARY EFFLUENT
CONVENTIONAL POLLUTANTS
Low
Groundwater
High
Groundwater
Average
Day
Max imuin
Day
Storm
Average
Day
Maximum
Day
Storm
Primary Effluent
377
592
1,150
657
9 47
1,270
Flow, mgd
BOD, mg/i
TSS, mg/i
121
67
158
87
106
87
75
- I1
106
70
97
83
monthly most probable number (MPN) of fecal coliform bacteria be less than 200 in
every 100 ml of effluent, commonly presented as 200 MPN/100 ml. A maximum level of
liOO MPN/100 ml is required by the NPDES permit.
During the interim primary treatment phase, anaerobic selector basins will be used
as temporary chlorine contact chambers. A temporary chlorine feed system will also
be installed. While adequate detention time is designed to be available in the
selector basins and the conduit which leads to the outfall, short circuiting of flow
may result in inadequate actual detention time. A failure in the temporary feeder
system could also occur. In both cases, inadequate mixing of the chlorine could
cause an increase in fecal coliforin count to levels in excess of the NPDES permit.
H.3.3.2 Secondary Treatment Phase
Three operating scenarios are considered during the secondary treatment phase:
secondary treatment of up to 1,080 mgd; up to 190 mgd of primary treated effluent
mixed with 1,080 mgd of secondary treated effluent; and primary treated effluent
flowing through the secondary treatment facilities during power outages.
H-35
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TABLE H.3.g NOW- CONVENT IONAL POLLUTANT EFFLUENT
CONCENTRATIONS AFTER PRIMARY TREATMENT
YEAR 1999, AVERAGE FLOW CONDITIONS (1)
AVERAGE REMOVAL EFFLUENT EFFLUENT
INFLUENT RATE, LOADINGS CONC.
LOADINGS PERCENT ((bid) (taft)
POLLUTANT Ctbid) (2)
METALS
Arsenic 7.6 25 5.7 0.00181
Caóniun 8.4 15 7.1 0.00227
Chrcmhmi 88.5 40 53.1 0.01689
Copper 399.8 35 259.9 0.08265
Lead 69.5 46 37.5 0.01 194
Mercury 5.0 22 3.9 0.00124
Wicket 79.1 15 67.2 0.02138
Se ten iun 53.3 10 48.0 0.01526
SlIver 18.0 30 12.6 0.00401
Zinc 866.2 60 519.7 0.16530
ACID BASE NEUTRALS
Butylbenzyt Phthatate 63.7 0 63.7 0.02026
Bis (2-Ethythexyl) Phthatate 78.3 0 78.3 0.02490
Di-N-Octyl Phthalate 65.8 0 65.8 0.02093
F torene 16.5 0 16.5 0.00525
VOLATILE ORGANICS (3)
Broqm riethane 62.3 NA 62.3 0.01981
Methylene ChLoride 120.3 0 120.3 0.03826
Chloroform 22.3 NA 22.3 0.00709
Tr iehloroethylene 43.6 20 34.9 0.01109
Benzene 16.5 0 16.5 0.00525
Tetrachlorethylene 61.7 0 61.7 0.01962
Ethy tbenzene 33.4 0 33.4 001062
Styrene 37.5 0 37.5 0.01193
PESTICIDES AND PCB
PCB 3.2 0 3.2 0.00102
ALdr lrt 0.7 0 0.7 0.00022
DDT 0.2 0 0.2 0.00006
Neptachlor 0.8 10 0.7 0.00023
Dieldrin 0.1 0 0.1 0.00003
1. Wastewater flow of 377 MCD was used to calculate effluent concentrations.
2. Average influent loadings were estimated jrIng the Facilities Plan (MWRA, STFP III , 1987).
3. “NA” represents no information available. No removaL of pollutant was •ssianed.
H-36
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TABLE N.3.h MOM-CONVENTIONAL POLLUTANT EFFLUENT CONCENTRATIONS
AFTER PRIMARY TREATMENT YEAR 1999.
NAXIMLJ4 LOADING CONDITIONS ON STORM DAY Cl)
NAXI JI REMOVAL EFFLUENT EFFLUENT
INFLUENT RATE, LOADINGS CONC.
LOADINGS PERCENT ((bid) (u iL)
POLLUTANT ((bid) (2)
METALS
ArsenIc 12.3 25 9.23 0.00087
Caóniun 14.8 15 12.58 0.00119
Chromlian 157.4 40 94.44 0.00892
Copper 639.3 35 415.54 0.03923
Lead 130.2 46 70.31 0.00664
Mercury 17.5 22 13.65 0.00129
NIckel 149.8 15 127.33 0.01202
SelenIui 153.9 10 138.51 0.01308
Silver 26.8 30 18.76 0.00177
ZInc 2840.1 40 1704.06 0.16088
ACID BASE NEUTRALS
ButyLbenzyl Phthalate 120.5 0 120.50 0.01138
Bis (2-EthyLhexyl) Phthalate 124.4 0 124.40 0.01174
Di -N•Octyl Phthatate 115.2 0 115.20 0.01088
Florene 16.5 0 16.50 0.00156
VOLATILE ORGANICS (3)
Bromomethane 106.8 NA 106.80 0.01008
Methylene Chloride 293.3 0 293.30 0.02769
Chloroform 42.8 NA 42.80 0.00404
Trich loroethylene 90.0 20 72.00 0.00680
Benzene 22.6 0 22.60 0.00213
Tetrach (oroethene 134.0 0 134.00 0.01265
Ethylbenzene 63.7 0 63.70 0.00601
Styrene 55.7 0 55.70 0.00526
PESTICIDES AND PCB
PCB 4.0 0 4.00 0.00038
Aldrin 1.0 0 1.00 0.00009
DDT 0.2 0 0.20 0.00002
Heptachlor 0.8 10 0.72 0.00007
Die (dr ln 0.1 0 0.10 0.00001
1. Wastewater flow of 1270 MCD was used to calculate effluent concentrations.
2. Naxinun influent loadings were estimated ó r1ng the Facilities Plan C N%JRA,STFP V,A,1987).
3. “NA” represents no information available. No removal of pollutant was asssuned.
H-37
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TABLE H.3.i CONVENTIONAL POLLUTANTS EFFLUENT CHARACTERISTICS
FOR UP TO 1,080 MGD SECONDARY TREATMENT,
YEAR 2020
Low
Groundwater
High
Groundwater
Average
Maximum
Average
Maximum
Day
Day
Storm
Day
Day
Storm
Secondary
Effluent
390
600
1,080
670
950
1,080
Flow, mgd
BOD
ib/d
118,800
203,500
360,300
111,800
320,300
360,300
mg/i
15
111
1 10
20
140
140
Percent
Removed
91
81
72
79
70
72
TSS
ib/d
118,800
203,500
360,300
111,800
320,300
360,300
mg/i
15
1 41
1 10
20
140
110
Percent
Removed
90
81
76
79
68
76
Source:
Adapted f
rom MWRA
, STFP III
, 1987.
H-38
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H.3.j for average loading conditions at an average flow rate of 390 mgd for the year
2020. Table H.3.k presents non-conventional pollutant characteristics for average
loading conditions at a flow rate of 1,080 mgd. Table H.3.l shows non-conventional
pollutant characteristics for maximum loading conditions during peak flow conditions
of 1,080 mgd when secondary treatment only is provided.
During periods when the flow rate exceeds 1,080 mgd, a mixed effluent of 1,080 mgd
of secondary treated effluent and a primary treated effluent up to 190 mgd would be
produced. Conventional pollutant characteristics of a mixed effluent would be as
shown on Table H.3.m. Non—conventional pollutant effluent characteristics for an
average loading period at a flow rate of 1,270 mgd would be as shown in
Table H.3.n. Removal rates for primary treated effluent for a flow of’ 190 rngd is
combined with removal rates for the most difficult removal conditions of peak flow
during high groundwater periods for the 1,080 mgd secondary treated effluent. This
combination of mixed effluent produces the worst case scenarios for pollutant
loadings during secondary treatment.
During power outages, primary treatment only would be provided, with the primary
effluent flowing through the secondary treatment facilities prior to disinfection.
Table FL3.o presents the conventional pollutant characteristics that could be
expected for the primary treated effluent. The same non-conventional pollutant
characteristics as presented in Tables H.3.g and H.3.h are expected for this
operating scenario.
A discussion of the impacts of the effluent for each of the operating scenarios as
it is discharged through the various outfall alternatives is presented in the
appropriate sections of Chapters LI and 5 of this Draft SEIS. The effluent
concentrations presented here for each of the operating scenarios are also discussed
in Chapters II and 5.
H—39
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TABLE H .3. J NON-CONVENTIONAL POLLUTANT EFFLUENT
CONCENTRATIONS AFTER SECONDARY TREATMENT, AVERAGE FLOW CONDITIONS
YEAR 2020 (1)
AVERAGE REMOVAL EFFLUENT EFFLUENT
INFLUENT RATE, L DINGS CONC.
L DINGS PERCENT ((bid) Ce il)
POLLUTANT ((b/d) (2)
METALS
Arsenic 7.6 50 3.8 0.00117
8.4 50 4.2 0.00129
Chr nh.i a 88.5 76 21.2 0.00653
Copper 399.8 82 72.0 0.02213
Lead 69.5 57 29.9 0.00919
Mercury 5.0 75 1.3 0.00038
NIckel 79.1 32 53.8 0.01654
Se leni 53.3 50 26.7 0.00819
SiLver 18.0 90 1.8 0.00055
Zinc 866.2 76 207.9 0.06391
ACID BASE NEUTRALS
Butylbenzyl Phthalate 63.7 95 3.2 0.00098
Bis C2-Ethylheiiyl) Phthalate 78.3 90 7.8 0.00241
Di-N-Octyl Phthalate 65.8 90 6.6 0.00202
Florene 16.5 90 1.7 0.00051
VOLATILE ORGANICS
Bromomethane 62.3 95 3.1 0.00096
Methylene Chloride 120.3 95 6.0 0.00185
ChLoroform 22.3 90 2.2 0.00069
Trich loroethyLene 43.6 95 2.2 0.00067
Benzene 16.5 95 0.8 0.00025
Tetrach lorethylene 61.7 90 6.2 0.00190
Ethy(benzene 33.4 95 1.7 0.00051
Styrene 37.5 90 3.8 0.00115
PFSTICIDES AND PCB
PCB 3.2 92 0.3 0.00008
A ldriri 0.7 90 0.1 0.00002
DDT 0.2 90 0.0 0.00001
HeptachLor 0.8 90 0.1 0.00002
Dieldrln 0.1 90 0.0 0.00000
1. Wastewater flow of 390 MOD was used to calcuLate effluent concentrations.
2. Average influent loadings were estimated ir1ng the Facilities Plan CMWRA, STFP III, 1987).
H-l O
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TABLE H.3.k NONCONVENTIONAL POLLUTANT EFFLUENT
CONCENTRATIONS AFTER SECONDARY TREATMENT, YEAR 2020 Cl)
AVERAGE REMOVAL EFFLUENT EFFLUENT
INFLUENT RATE, LOADINGS CON.
LOADINGS PERCENT CLb/d) (u /t)
POLLUTANT (tb/d) (2)
METALS
Arsenic 7.6 50 3.8 0.00042
Caósiun 8.4 50 4.2 0.00047
Chramlir 88.5 76 21.2 0.00236
Ccçper 399.8 82 72.0 0.00799
Lead 69.5 57 29.9 0.00332
Mercury 5.0 75 1.3 0.00014
N cke1 79.1 32 53.8 0.00597
Seteniias 53.3 50 26.7 0.00296
S ilver 18.0 90 1.8 0.00020
Zinc 866.2 76 207.9 0.02308
ACID BASE NEUTRALS
Butylbenzyt Phthalate 63.7 95 3.2 0.00035
Bis (2 Ethylhexyl) Phthalate 78.3 90 7.8 0.00087
Di•N-Octyl Phthalate 65.8 90 6.6 0.00073
F lorene 16.5 90 1.7 0.00018
VOLATILE ORGANICS
Bromomethene 62.3 95 3.1 0.00035
Nethylene Chloride 120.3 95 6.0 0.00067
Chloroform 22.3 90 2.2 0.00025
Tr lchloroethylene 43.6 95 2.2 0.00024
Benzene 16.5 95 0.8 0.00009
Tetrachlorethylene 61.7 90 6.2 0.00069
Ethylbenzene 33.4 95 1.7 0.00019
Styrene 37.5 90 3.8 0.00042
PESTICIDES AND PCB
PCB 3.2 92 0.3 0.00003
A ldrin 0.7 90 0.1 0.00001
DDT 0.2 90 0.0 0.00000
Heptachtor 0.8 90 0.1 0.00001
Dieldrin 0.1 90 0.0 0.00000
1. Wastewater fLow of 1080 M CD was used to calculate effluent concentrations.
2. Average influent Loadings were estimated rIng the Facilities Plan (MWRA, STFP III, 1987).
H LI 1
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TABLE N.3. I NON-CONVENTIONAL POLLUTANT EFFLUENT
CONCENTRATIONS AFTER SECONDARY TREATMENT
YEAR 2020, MAXI LOADING CONDITIONS (1)
MAXI* REMOVAL EFFLUENT EFFLUENT
INFLUENT RATE, LOADINGS CONC.
LOADINGS PERCENT (lb/d) (u Il)
POLLUTANT (lb/d) (2)
METALS
Arsenic 12.3 50 6.2 0.00068
Cadniun 14.8 50 7.4 0.00082
Chromiun 157.4 76 37.8 0.00419
Copper 639.3 82 115.1 0.01278
Lead 130.2 57 56.0 0.00622
Mercury 17.5 75 4.4 0.00049
NickeL 169.8 32 101.9 0.01131
Seleniun 153.9 50 77.0 0.00854
Silver 26.8 90 2.7 0.00030
Zinc 2840.1 76 681.6 0.01568
ACID BASE NEUTRALS
Butylbenzyt Phthalate 120.5 95 6.0 0.00067
Bis (2-EthyLhexyt) Phthatate 124.4 90 12.4 0.00138
Di-N-Octyl Phthatate 115.2 90 11.5 0.00128
F lorene 16.5 90 1.7 0.00018
VOLATILE ORGANICS
Bromomethane 106.8 95 5.3 0.00059
NethyLene Chloride 293.3 95 14.7 0.00163
ChLoroform 42.8 90 4.3 0.00048
Trichloroethylene 90.0 95 4.5 0.00050
Benzene 22.6 95 1.1 0.00013
Tetrachiorethytene 134.0 90 13.4 0.00149
Ethylbenzene 63.7 95 3.2 0.00035
Styrene 55.7 90 5.6 0.00062
PESTICIDES AND PCB
PCB 1.0 92 0.1 0.00001
ALdrin 1.0 90 0.1 0.00001
DOT 0.2 90 0.0 0.00000
HeptachLor 0.8 90 0.1 0.00001
Dietdrin 0.1 90 0.0 0.00000
1. Wastewater f Low of 1080 M was used to calculate effluent concentrations.
2. Maxinnin influent loadings were estimated ó ring the Facilities Plan CMWRA, STFP V,A, 1987).
H_142
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TABLE H.3.m CONVENTIONAL POLLUTANT LOADINGS, NIXED PRIMARY-
SECONDARY EFFLUENT, YEAR 2020
Low
Groundwater
High Groundwater
Average
Maximum
Average Maximum
Day
Day
Storm
Day Day
Storm
Flow, mgd
Secondary Component
390
600
1,080
670 950
1,080
Primary Component
0
0
70
0 0
190
Total
390
600
1,150
670 950
1,270
BOD
Secondary Component, ib/d
118,800
203,500
360,300
111,800 320,300
360,300
Primary Component, ib/d
0
0
116,000
0 0
1116,500
Total, lb/d
118,800
203,500
1106,300
111,800 320,300
506,800
mg/i
15
111
1414
20 40
118
Percent Removed
91
81
68
79 70
61
TSS
Secondary Component, lb/d
118,800
203,500
360,300
111,800 320,300
360,300
Primary Component, ib/d
0
0
146,300
0 0
111,100
Total, lb/d
148,800
203,500
1406,300
111,800 320,300
1471,1400
mg/i
15
141
1 12
20 110
1414
Percent Removed
90
80
73
79 68
68
Source: MWRA STFP III, 1987.
H _L 13
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1. Flow conditions are i to 190 MCD primary treated effluent mixed with 1080 PlOD secondary treated effluent for a total of 1270 MCD.
2. Estimates based on 190 MCD.
3. Estimates based on 1080 MCD.
4. “NA” represents no Information available. No removal of pollutant was assuned.
TABLE H.3.n NON•CONVENTIONAL POLLUTANTS, MIXED PRIPlARY SECONDARY
EFFLUENT, YEAR 2020 (1)
PRIMARY (2) SECONDARY (3) PLANT
AVtK bt KL UVAL tIPLUtNI FFLUtNI REMOVAL EFFLUENT EFFLUENT EFFLUENT EFFLUENT
INFLUENT RATE, LOADINGS CONC. LOADINGS CONC. LOADING, CONC.
LOADINGS PERCENT ((bid) (mg/I) PERCENT (lb/d) (mg/I) ((bid) (mg/I)
POLLUTANT ((bid)
METALS
Arsenic
7.6
25
0.9
0.00054
40
3.9
0.00043
4.7
0.00045
Cachiiiun
8.4
15
1.1
0.0006?
40
6.3
0.00068
5.4
0.00051
Chromluit
88.5
40
7.9
0.00501
60
30.1
0.00334
38.0
0.00359
Copper
Lead
399.8
69.5
35
46
38.9
5.6
0.02454
0.00354
70
70
102.0
17.7
0.01132
0.00197
140.9
23.3
0.01330
0.00220
Mercury
5.0
22
0.6
0.0003?
70
1.3
0.00014
1.9
0.00018
Nickel
79.1
15
10.1
0.00635
30
47.1
0.00523
57.1
0.00540
Selenlun
53.3
10
7.2
0.00453
40
27.2
0.00302
34.6
0.00325
Silver
18.0
30
1.9
0.00119
80
3.1
0.00034
4.9
0.0004?
Zinc
866.2
40
77.8
0.04907
70
221.0
0.02453
298.7
0.02820
ACID BASE NEUTRALS
Butylbenzyl PhtheLete
63.7
0
9.5
0.00601
70
16.3
0.00180
.
25.8
0.00243
Bis (2-Ethylhexyl) Phtha(ete
78.3
0
11.7
C.00739
50
33.3
0.00370
45.0
0.00425
Di -N-Octyl Phthalete
Florene
65.8
16.5
0
0
9.8
2.5
0.00621
0.00156
70
70
16.8
4.2
0.00186
0.00047
26.6
6.7
0.00251
0.00063
VOLATILE ORGANICS
(4)
Bro,nomethene
62.3
NA
62.3
0.03932
75
13.2
0.00147
75.5
0.00713
Methytene Chloride
120.3
0
18.0
0.01136
40
61.4
0.00681
79.4
0.00749
Chloroform
22.3
NA
22.3
0.01407
50
9.5
0.00105
31.8
0.00300
Trich loroethylene
43.6
20
5.2
r Q3 9
70
11.1
0.00123
16.3
0.00154
Benzene
16.5
.
0
2.5
)156
70
4.2
0.00047
6.7
0.00063
Tetrachlorethylene
61.7
0
9.2
)583
70
15.7
0.00175
25.0
0.00236
Ethylbenzene
33.4
0
5.0
0. 3315
70
8.5
0.00095
13.5
0.00128
Styrene
37.5
0
5.6
0.00354
70
9.6
0.00106
15.2
0.00143
PESTICEDES AND PCB
PCB
3.2
0
0.5
0.00030
70
0.8
0.00009
1.3
0.00012
ALdrln
0.7
0
0.1
0.0000?
70
0.2
0.00002
0.3
0.00003
DDT
0.2
0
0.0
0.00002
70
0.1
0.00001
0.1
0.00001
I leptach(or
0.8
10
0.1
0.00007
70
0.2
0.00002
0.3
0.00003
Die(drin
0.1
0
0.0
0.00001
70
0.0
0.00000
0.0
0.00000
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TABLE H.3.o CONVENTIONAL POLLUTANT EFFLUENT CHARACTERISTICS,
PRIMARY TREATMENT, YEAR 2020
Low
Groundwater
High
Groundwater
Average
Day
Maximum
Day
Storm
Average
Day
Maximum
Day
Storm
Flow, mgd
390
600
1,150
670
950
1,270
ROD
ib/d
mg/i
A 08,000
125
826,000
165
981,000
102
Z33,000
77
886,000
112
1,106,500
10 4
TSS
ibId
mg/i
227,000
70
Z70,000
gZ
.
8 41,000
88
238,000
L 3
596,000
75
939,100
89
H_L 15
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REFERENCES
MWRA, STFP III, 1987. Secondary Treatment Facilities Plan, Volume III, Treatment
Plant.
MWRA, STFP III, L, 1987. Secondary Treatment Facilities Plan, Volume III, Appendix
L, Flows and Loads.
MWRA, STFP III, J, 1987. Secondary Treatment Facilities Plan, Volume III,
Appendix J, Design Criteria.
MWRA, STFP III, C, 1987. Secondary Treatment Facilities Plan, Volume III, Appendix
C, Unit Process Descriptions.
MWRA, STFP III, M, 1987. Secondary Treatment Facilities Plan, Volume III, Appendix
M, Stacked Clarifiers.
MWRA STFP III, H, 1987. Secondary Treatment Facilities Plan, Volume III, Appendix
H, Power.
MWRA, STFP III, B, 1987. Secondary Treatment Facilities Plan, Volume III,
Appendix B, Sampling Program and QAQC.
MWRA, STFP V, 1987. Secondary Treatment Facilities Plan, Volume V, Effluent
Outfall.
Petrasek, Albert C., et al., 1983. Fate of Toxic Organic Compounds in Wastewater
Treatment Plants. J. of the Water Pollution Control Fed. , Vol. 55. No. 10:
1286—1296.
USEPA, 1986. Report to Congress on the Discharge of Hazardous Wastes to Publicly
Owned Treatment Works (The Domestic Sewage Study). Vol. I, App. 0. Washington,
D.C.
USEPA, 1982. Fate of Priority Pollutants in Publicly Owned Treatment Works. Vol. 1,
II. Washington, D.C.
USEPA, 1977. Federal Guidelines, State and Local Pretreatment Programs. Vol. I,
II. Washington, D.C.
USEPA, 1971L. Design Criteria for Mechanical, Electric, and Fluid System and
Component Reliability. Washington, D.C.
WPCF, 1977. Manual of Practice 8, Wastewater Treatment Plant Design . Lancaster,
PA.
H_Z16
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APPENDIX H TABLES
COMPARISON OF REMOVAL RATES
H- 1 47
-------
110
1. NA indicates no information
2. MWRA, STFP III, 1987.
3. USEPA, 1977.
L I. USEPA, 1982.
MWRA
Faci .j ies
Pollutant Plan ’ 1
TABLE H. 1 COMPARISON OF REMOVAL RATES FOR METALS, PRIMARY TREATMENT 1
State and
Local
Pretreatip çt
Programs’ ’
Fate of
Priority
Pollutants
Antimony
30
NA
NA
Arsenic
25
NA
NA
Boron
2
NA
NA
Cadmium
15
8
15
Chromium
140
26
27
Copper
35
26
22
Cyanide (Total)
10
NA
27
Lead
46
2 14
57
Mercury
22
27
10
Molybdenum
10
NA
NA
Nickel
15
6
1 14
Selenium
10
NA
i
Silver
30
NA
20
Zinc
31 27
available.
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TABLE H.2 COMPARISON OF REMOVAL RATES FOR METALS, SECONDARY TREATMENT 1
State and Fate of Priority poiiutants(U
MWRA Local 50% of 90% of 02 Secondary
Faci j ies Pretreatrpççt Plants Plants Activa Activa g Appendix 0 7
Pollutant Plan” Programs’” Minimum Minimum Sludge’’ Sludge’ ‘ Acclimated 140 POTW
Antimony 60 (71.5)
Arsenic 50 50 (93.9)
Boron 5
Cadmium 50 17 93 II 83 85 27 86.6
Chromium 76 146 76 148 76 814 70 78.9
Copper 82 57 82 146 92 814
Cyanide 60 59 5 80 62 90
(Total)
Lead 57 39 97 35 97 82 90 88.5
Mercury 75 39 86 25 83 76 50 82
Molybdenum 50
Nickel 32 20 35 8 18 314 35 147.5
Selenium 50 50
Silver 90 95 66 80 83 90 91.3
Zinc 76 58 77 LIZ! 81 81
1. Blank space indicates information on percent removal of metal from secondary
treatment not available.
2. MWRA, STFP III, 1987.
3. USEPA, 1977. Removal rates for activated sludge.
LI. USEPA, 1982, Tables 10 and 11.
5. For 02 activated sludge, results are based on one to three plants reporting, median
value given.
6. For secondary sludge, two to 22 plants reporting, maJority is 22 plants, median
value given.
7. USEPA, 1986. Parentheses indicate less than five plants reporting.
H-Z!9
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TABLE H.3 COMPARISON OF REMOVAL RATES QR ACID BASE
PRIMARY TREATMENT
NEUTRALS,
Pollutant
MWRA
Faci 4 ies
Plan’ ‘
Fate of
Priority
Pollutants
3
Phenol
20
8
Benzyl Alcohol
NA
NA
1,2 — Dichlorobenzene
NA
NA
2 - Methy]phenol
.
NA
NA
4 - Methyiphenol
NA
NA
Benzoic Acid
NA
NA
Napthalene
0
14 1 4
2 - Methylnapthalene
2,4,5 - Trichlorophenol
NA
NA
NA
NA
Dimethyl Phthalate
24
NA
Diethyl Phthalate
0
56
N — Nitro-
sodiphenylamine
NA
NA
Di-N—Butylphthalate
Butylbenzyl Phthalate
0
0
36
62
Bis (2 - Ethyihexyl)
Phthalate
0
0
Di-N-Oct” °hthalate
0
NA
Florene
0
NA
1. NA indicates no information is available.
2. MWRA, STFP III, 1987.
3. USEPA, 1982.
H-50
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TABLE H. 4 COMPARISON OP REMOVAL RAIlS ACID BASE NEUTRALS,
SECONDARY TREATMENT 1
Pollutant
MWRA
Faci J 1 ties
Plant ’)
Fate
of Priority Po1lutants 3
Rate of
Toxic
Pol1utants 5
Appendix o(6)
50%
Minimum
90%
Minimum
O
Ac
sludge’- ‘
Activated
Sludge
Acclimated
Unacclimated
Median Low
40 POTW
Phenol
95
99
46
99+
89
95
95
85 80
97
Benzyl Alcohol
90
1,2 — Dichlorobenzene
90
90
87 85
92
2 — Methyiphenol
90
4 — Methyiphenol
90
Benzoic Acid
90
Napthalene
95
99+
85
92
2 — Methylnapthalene
90
2,4,5 — Trichiorophenol
90
Dimethyl Phthalate
95
98
95
65 60
(100)
Diethyl Phthalate
90
99+
67
91
97
N — Nitro—
sodiphenylamine
90
Di-N—Butylphthalate
90
51
4
98
68
94
90
90 90
88
Butylbenzyl Phthalate
95
99+
40
84
94
96
95
90 90
99
Bis (2 — Ethyihexyl)
Phthalate
90
58
15
64
62
79
90
90 90
74
Di—N—Octyl Phthalate
90
83
90
90 90
88
Florene
90
no information is
availabi
e.
1. Blank spaces indicate
2. MWRA, STFP III, 1987.
3. USEPA, 1982.
4. Results are based on one to three plants reporting.
5. Peirasek, 1983.
6. USEPA, 1986. Parentheses indicate less than five plants reporting.
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TABLE 11.5 COMPARISON OF REMOVAL RATES OR VOLATILE ORGANICS,
PRIMARY TREATMENT )
Pollutant
MWRA
FaciJ . ies
Plan’ ‘
Fate of
Priority
Pollutants 3
Brornomethane
Methylene Chloride
Acetone
NA
0
NA
NA
0
NA
Carbon Disulfide
Trans - 1,2 Dichlor-
ethene -
Chloroform
NA
36
NA
NA
36
1 4
2 - Butanone
1,1,1 — Trichloroethane
Trichioroethylene
NA
L O
20
NA
4o
20
Benzene
- Methyl - 2 -
Pentanone
Tetrachloroethylene
0
NA
0
25
NA
I
1,1,2,2 — Tetrachlor-
oethene
Toluene
Chlorobenzene
NA
0
NA
NA
0
NA
Ethylbenzene
Styrene
Total Xylene
0
0
NA
13
NA
NA
1. NA indicates no information available.
2. MWRA, STFP III, 1987.
3. USEPA, 1982.
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TABLE 11.6 COMPARISON OF REMOVAL RATES FOR VOLATILE ORGANICS, SECONDARY TREAThENT 1)
thylbenzene
Styrene
Total Xylene
1. Blank spaces indicate no information
2. HWRA, STEP III, 1987.
3. USEPA, 1982.
I. Results are based on one to three plants reporting, medium value given.
5. Results are based on 2 to 22 plants reporting with the majority using 22 plants, medium value given.
6. USEPA, 1986. Parentheses indicate less than five plants reporting.
is available.
Pollutant
MWRA
Facll1 çs
Plan’ ‘
50%
Minimum
Fate of
90%
Minimum
Priority Pollutants 3
0
Activated Sludge’ ‘
Activated 5
Sludge
APPENDIX o 6
Acclimated
Unacclimated
Med.
Low
P0 1 W
Bromomethane
95
95
95
95
(100)
Methylene Chloride
95
56
3
3 1 1
I8
95
87
85
——
Acetone
95
95
50
30
--
Carbon Disulfide
95
95
85
80
Trans-1,2 Dichlorethylene
90
99+
79
85
80
90
80
80
93
Chloroform
90
62
11
50
62
90
80
80
68
2-Butanone
90
1,1,1—Trichloroethane
95
914
80
80
88
95
90
85
88
Trichioroethylene
95
97
72
67
90
95
87
85
92
Benzene
95
99.
66
,.
77
95
90
90
9 34
4-Methyl-2-Pentanone
90
Tetrachioroethylene
90
85
30
5
82
1,1,2,2-Tetrachloroethene
90
Toluene
90
96
70
99+
93
95
90
90
98
Chlorobenzene
90
90
90
90
(99.5)
J1
95 99+ 86 90 86 95
90
90
90
90
90
90
95
95
87
85
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TABLE H.? COMPARISON OF REMOVAL RATES FOR PESTICIDES AND PCB,
PRIMARY TREATMENT (1)
Pollutant
PCB
0
Aldrin
0
DDT
0
Heptachlor
10
Dieldrin
0
No information was available from data sources for primary treatment removal
rates for the listed pesticides and PCB.
2. MWRA, STFP V, A, 1987.
MWRA
Facilities
Plan (2)
H-5 1 4
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TABLE H.8 COMPARISON OF REMOVAL RATES FOR PESTICIDES AND PCB’S,
SECONDARY TREATMENT (1)
Pollutant
MWRA
Facilities
Plan (2)
Appendix
0
(3)
Acclimated
Med.
Unacclimated
Low
PCB
92
92
92
92
Aidrin
90
90
90
90
DDT
90
NA
NA
NA
Heptachior
90
NA
NA
NA
Dieldrin
90
NA
NA
NA
1. NA indicates no information available.
2. MWRA, STFP V, A, 1987.
3. USEPA, 1986.
H-55
-------