aquatic environment assessment of environmental...

AQUATIC ENVIRONMENT ASSESSMENT OF ENVIRONMENTAL EFFECTS

TECHNICAL SUPPORT DOCUMENT NEW NUCLEAR - DARLINGTON

ENVIRONMENTAL ASSESSMENT NK054-REP-07730-00013 Rev 000

Submitted To:

Ontario Power Generation Inc. Prepared By:

Golder Associates and SENES Consultants Limited

September 2009

New Nuclear - Darlington Aquatic Environment

Environmental Assessment Assessment of Environmental Effects

Ontario Power Generation Inc. Technical Support Document

ES-1

EXECUTIVE SUMMARY

Ontario Power Generation (OPG) was directed by the Ontario Minister of Energy in June 2006

to begin the federal approvals process, including an environmental assessment (EA), for new

nuclear units at an existing site. OPG has begun this process for a new nuclear power generating

station at the Darlington Nuclear site (DN site).

This Assessment of Environmental Effects Technical Support Document (TSD) relates to the

Aquatic Environment (AE), and is one of a series of related documents prepared by the EA

Consulting Team. Following on the separate series of Existing Conditions TSDs, this TSD

describes the changes and effects in the context of baseline conditions that are considered likely

to occur as a result of implementing the Project.

The AE component is comprised of aquatic habitat and aquatic biota. Baseline or existing

conditions were described in the Aquatic Environment Existing Conditions TSD, including on-

site and Lake Ontario nearshore aquatic features. Selection of Valued Ecosystem Components

(VECs) focused on habitats, and included Darlington Creek and the Lake Ontario nearshore to

address physical effects on these features during the Site Preparation and Construction phase,

and aquatic biota, including forage species, benthivorous fish and predatory fish. The indicator

species for the Darlington Creek VEC is white sucker. VEC indicator species for the Lake

Ontario nearshore and aquatic biota VECs include a range of species and groups for which there

may be concern during the Site Preparation and Construction phase and the Operation and

Maintenance phase. These include:

Benthic invertebrates;

Fish species: Round goby; Emerald shiner; Alewife; White sucker; Round whitefish;

Lake sturgeon; American eel; Lake trout; and Salmonid sportfish.

The assessment addressed two primary effects pathways, related to physical changes to aquatic

habitat and organism-level effects involving intake losses and thermal discharge.

During Site Preparation and Construction, on-site and Lake Ontario nearshore aquatic habitats

will be physically altered to varying degrees by changes to grades, substrate and drainage

patterns. Mitigation will focus on a comprehensive fish habitat mitigation, restoration and

compensation strategy that will be developed at a more advanced design stage to address

Fisheries Act (FA) requirements and, more broadly, to maintain functioning aquatic habitat on

site that is integrated with wetland and terrestrial habitats. Preliminary discussions have already

been initiated with the Department of Fisheries and Oceans (DFO), Ontario Ministry of Natural

Resources (OMNR) and local conservation groups.

During the Operations and Maintenance Phase, withdrawal of cooling water will cause some fish

impingement and entrainment of fish and invertebrates. Cooling water discharge will change

water temperatures in a portion of the Lake Ontario nearshore, primarily within a limited mixing

zone. In-design mitigation of both intake and discharge effects includes siting in relatively

unproductive areas of the nearshore. Additional mitigation of intake losses will include a porous

veneer intake structure for once-through cooling or other fish deterrent strategies for a cooling




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tower intake. The discharge, in either case, will be designed as a diffuser to minimize thermal

effects.

As proven in-design mitigation will be implemented to address operational effects, the mitigation

of habitat effects related to Site Preparation and Construction appears to be the main AE

challenges to implementing the Project. OPG and consultants are currently in discussion with

DFO and other stakeholders concerning fish habitat losses and credible compensation options

have been identified, and are summarized in Appendix B.

In accordance with DFO Policy of the Management for Fish Habitat (DFO 1986), with specific

reference to the principle of ‘No Net Loss of the Productive Capacity of Fish Habitat’, OPG

agrees to undertake measures to compensate for and mitigate against, the loss of fish habitat

arising from the New Nuclear at Darlington (NND) Project. OPG has initiated the process by

submitting an Application for Authorization for Works or Undertakings Affecting Fish Habitatsto DFO (September 30, 2009) and will continue to work with DFO staff to complete the

compensation plan which will be incorporated into a subsection 35(2) authorization of the

Fisheries Act (FA). The plan will include components that will also address the requirements

under section 32 of the FA, if necessary, that states no person shall destroy fish by any means

other than fishing except as authorized by the Minister.

AE selected bounding scenarios from the four development scenarios and three reactor operation

scenarios described in the Scope of the Project for EA Purposes TSD. For the Site Preparation

and Construction Phase, Site Development Scenario 1, Four ACR 1000 Reactors with Once-

Through Cooling, were chosen. Potential interactions and their resolution with respect to

assessment and mitigation included:

Bridge crossing of the main branch of Darlington Creek will be mitigated by following

the applicable DFO Operational Statement, or aligning the access road further to the

west, resulting in negligible residual effect;

Loss of Treefrog, Polliwog and Dragonfly ponds will be mitigated by restoration of

aquatic habitat within new on-site drainage features, resulting in negligible residual

effect;

Loss of portions of intermittent tributaries to Darlington Creek will be mitigated by

restoration within reconfigured site drainage at the north tributary (which may remain

connected to Darlington Creek) and compensation within site drainage channels within

the south tributary (which may be re-directed towards Lake Ontario). Negligible residual

effects will result;

Alteration/disruption of Coot’s Pond will be avoided to the extent practicable and any

affected areas of the pond will be restored, resulting in negligible residual effects;

Alteration of upper portions of an intermittent tributary to Lake Ontario near Coot’s Pond

will be mitigated by restoration of habitat in on-site drainage courses, resulting in

negligible residual effect;

Lake infill (approximately 40 hectares) in front of the Darlington Nuclear Generating

Station (DNGS) and New Nuclear Darlington (NND) sites will be addressed by fish

habitat compensation that will be designed and negotiated with the agencies at a later

stage of Project design, resulting in negligible residual effect;




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Blasting and excavation (approximately 1.1 hectares) for the porous veneer intake will

follow DFO guidelines for the use of explosives to minimize incidental fish losses,

resulting negligible residual effect; and

Blasting and excavation (cumulative area of approximately 0.7 hectares) for diffuser

ports will follow DFO guidelines for the use of explosives to minimize incidental fish

losses, resulting negligible residual effect.

For the Operation and Maintenance Phase, Reactor Operations Scenario 1, Four ACR-1000

Reactors, were chosen as the bounding scenario as it involves the once-through cooling water

system. Potential interactions included:

Impingement and entrainment (I&E) of aquatic organisms, particularly fish (adults,

juvenile, eggs and larvae). I&E losses will be mitigated by the use of a lakebottom porous

veneer intake structure sited in approximately 10 meters depth of water in the Lake

Ontario nearshore. This configuration has proven successful at DNGS and is expected to

result in negligible residual effects at NND;

Thermal effects on habitat suitability and aquatic organisms will be mitigated by the use

of a lakebottom diffuser sited in approximately 10-20 meters of water in the Lake Ontario

nearshore. This configuration has proven successful at DNGS and is expected to result in

negligible residual effects at NND; and

Nuisance nutrient and algae conditions created in the nearshore by the lake infill

configuration will be mitigated, if necessary, according to an adaptive management

strategy that will monitor for the incidence of algae problems and will determine

management strategies that will result in negligible residual effects.

In addition, thermal effects of an alternative once-through cooling scenario involving the

Pressurized Water Reactor (PWR) which has an increased discharge water temperature as high

as 15.6oC and a flow rate of 135 m

3/s was addressed. However, as Surface Water Environment

(SWE) concluded that a similar mixing zone and thermal plume would occur, it was considered

to be bounded by Reactor Operations Scenario 1, Four ACR-1000 Reactors, with a maximum

discharge temperature of 9oC and a flow rate of 250 m

3/s for AE purposes. Negligible residual

thermal effects were predicted.

AE also addressed fish losses associated with a cooling tower option. Thermal effects of the

cooling tower discharge were considered to be bounded by the assessment of once-through

cooling. Fish losses, although bounded by the once-through scenario, were discussed for

comparison. Fish losses associated with the cooling tower option were lower than those

associated with once-through cooling, owing primarily to its much reduced water intake rate.

Similar to the once-through option, the cooling tower option was also expected to result in

negligible residual I&E effects.




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TABLE OF CONTENTS

Page No.

EXECUTIVE SUMMARY ............................................................................................................ 1

1. INTRODUCTION ........................................................................................................... 1-1

1.1 Background .......................................................................................................... 1-1

1.1.1 The New Nuclear - Darlington Project .................................................... 1-1

1.1.2 The New Nuclear - Darlington Environmental Assessment.................... 1-2

1.2 Technical Support Document (TSD) ................................................................... 1-2

1.3 Description of the Aquatic Environment Component.......................................... 1-3

1.3.1 Aquatic Habitat VECs.............................................................................. 1-4

1.3.2 Aquatic Biota VECs (Forage Species, Benthivorous Fish and

Predatory Fish)......................................................................................... 1-5

2. EFFECTS ASSESSMENT METHODOLOGY .............................................................. 2-1

2.1 Assessment Framework ....................................................................................... 2-1

2.2 Assessment Basis, Spatial Boundaries, Methods and Criteria............................. 2-2

2.2.1 Project Basis for the Assessment ............................................................. 2-2

2.2.2 Spatial Boundaries for the Assessment.................................................... 2-3

2.2.3 Analytical Methods for the Assessment .................................................. 2-8

2.2.4 Criteria for the Assessment...................................................................... 2-9

2.3 Process Steps for Determination of Likely Environmental Effects ..................... 2-9

2.3.1 Detailed Screening for Potential Project-Environment Interactions........ 2-9

2.3.2 Evaluation for Likely Measurable Changes in the Environment............. 2-9

2.3.3 Assessment of Likely Effects on the Environment................................ 2-11

2.3.4 Consideration of Mitigation and Determination of Likely Residual

Effects .................................................................................................... 2-11

3. ASSESSMENT AND MITIGATION OF ENVIRONMENTAL EFFECTS.................. 3-1

3.1 Detailed Screening for Potential Project-Environment Interactions.................... 3-1

3.2 Evaluation for Likely Change to the Environment .............................................. 3-6

3.2.1 Site Preparation and Construction Phase ................................................. 3-7

3.2.1.1 Mobilization and Preparatory Work and Excavation and Grading3-7

3.2.1.2 Marine and Shoreline Works - Lake Infill ................................... 3-8

3.2.1.3 Construction of Intake and Discharge Structures......................... 3-9

3.2.1.4 Management of Stormwater ......................................................... 3-9

3.2.2 Operation and Maintenance Phase........................................................... 3-9

3.2.2.1 Operation of Condenser Circulating Water, Service Water and

Cooling Systems........................................................................... 3-9

3.3 Assessment of Likely Effects on the Environment ............................................ 3-10

3.3.1 Site Preparation and Construction Phase ............................................... 3-10

3.3.1.1 Darlington Creek Crossing......................................................... 3-10

3.3.1.2 Removal of Upper Reaches of Intermittent Tributaries to

Darlington Creek ........................................................................ 3-11

3.3.1.3 Removal of On-Site Ponds......................................................... 3-12

3.3.1.4 Alteration/Disruption of Coot’s Pond ........................................ 3-15




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3.3.1.5 Alteration of Upper Reaches of Intermittent Lake Ontario

Tributary..................................................................................... 3-16

3.3.1.6 Lake infill ................................................................................... 3-16

3.3.1.7 Construction of Intake and Discharge Structures....................... 3-21

3.3.2 Operation and Maintenance Phase......................................................... 3-23

3.3.2.1 Impingement and Entrainment ................................................... 3-23

3.3.2.2 Impingement............................................................................... 3-23

3.3.2.3 Entrainment ................................................................................ 3-30

3.3.2.4 Thermal Discharge: Once-Through Cooling System................. 3-32

3.3.2.5 Comparison of Weekly Maximum Hourly Temperatures (WMHT)

to Round Whitefish Temperature Benchmarks.......................... 3-37

3.3.2.6 Thermal Discharge: Cooling Tower Option............................... 3-43

3.3.2.7 Lake Infill Structure ................................................................... 3-43

3.3.3 Summary of Effects Advanced for Mitigation....................................... 3-44

3.4 Consideration of Mitigation and Determination of Likely Residual Effects ..... 3-44

3.4.1 Access Road Crossing of Darlington Creek .......................................... 3-47

3.4.2 Removal of On-Site Ponds (Treefrog, Dragonfly and Polliwog

Ponds) .................................................................................................... 3-47

3.4.3 Removal of Upper Reaches of Intermittent Tributaries to

Darlington Creek.................................................................................... 3-48

3.4.4 Alteration/Disruption of Coot’s Pond.................................................... 3-48

3.4.5 Alteration of Upper Reaches of Intermittent Lake Ontario

Tributary ................................................................................................ 3-49

3.4.6 Lake Infill............................................................................................... 3-49

3.4.7 Construction of Intake and Discharge Structures .................................. 3-49

3.4.8 Impingement and Entrainment............................................................... 3-50

3.4.9 Thermal Discharge................................................................................. 3-50

3.5 Potential Consequence of Climate Change on Predicted Effects ...................... 3-50

3.6 Section 35(2) Proposed Compensation Plan...................................................... 3-51

3.7 Ecosystem Dynamics –Invasive Species ........................................................... 3-52

4. REFERENCES ................................................................................................................ 4-1

LIST OF APPENDICES

APPENDIX A NEW NUCLEAR – DARLINGTON – EA BASIS TABLE A-1

APPENDIX B COMPENSATION DEVELOPMENT OPTIONS TABLE B-1




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LIST OF FIGURES Page No.

2.2-1 Site Study Area.............................................................................................................. 2-5

2.2-2 Local Study Area........................................................................................................... 2-6

2.2-3 Regional Study Area ..................................................................................................... 2-7

3.3.1-1 DN Site Aquatic Features............................................................................................ 3-14

3.3.1-2 Distribution of Sediment Types Identified by Underwater Video within the

Proposed Lake Infill Area ........................................................................................... 3-18

3.3.1-3 Benthic Invertebrate Sampling Locations within the Proposed Lake Infill Area ....... 3-18

3.3.2-1 Weekly Maximum Hourly Temperatures (1993-1996) .............................................. 3-42




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LIST OF TABLES

Page No.

2.3.2-1 Range and Relevance of Potential Change in the AE ................................................. 2-10

3.1-1 Potential Project-Environment Interactions in the AE.................................................. 3-2

3.2-1 Evaluation Criteria used in the AE................................................................................ 3-6

3.3.2-1 DNGS Impingement Loss Estimates (1993-1996, 2006-2007) .................................. 3-24

3.3.2-2 Comparison of Entrainment and Impingement Estimated Losses at Different

Plants on the Great Lakes............................................................................................ 3-27

3.3.2-3 Estimated Total Annual Impingement Losses ............................................................ 3-28

3.3.2-4 Estimated Alewife Impingement for the Cooling Tower Option................................ 3-29

3.3.2-5 MWAT above Ambient Values along the Perimeter of the Mixing Zone .................. 3-35

3.3.2-6 Maximum Weekly Average Temperatures (°C) for Round Whitefish ....................... 3-38

3.3.2-7 Weekly Maximum Hourly Temperatures (WMHT) from the DNGS Thermal Plume

Study Data ................................................................................................................... 3-39

3.3.2-8 Mean Air Temperatures Recorded from Environment Canada’s Weather

Station at Pearson International Airport (°C).............................................................. 3-41

3.3.2-9 Total Precipitation Recorded from Environment Canada’s Weather Station

at Pearson International Airport (mm) ........................................................................ 3-41

3.4-1 Summary of Likely Environmental Effects, In-Design Mitigation Measures

and Mitigation Recommendations .............................................................................. 3-45




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SPECIAL TERMS

Units

kg kilogram

cm centimetre

oC degrees Celsius

ft/s feet per second

m metre

m/s metre per second

m3/s cubic metre per second

Abbreviations and Acronyms

AE Aquatic Environment

CEAA Canadian Environmental Assessment Act

CCW Condenser Circulating Water

CLOCA Central Lake Ontario Conservation Authority

CN Canadian National Railway Company

CNSC Canadian Nuclear Safety Commission

DEER Darlington Ecological Effects Review

DFO Fisheries and Oceans Canada

DN Darlington Nuclear

DNGS Darlington Nuclear Generating Station

EA Environmental Assessment

EIS Environmental Impact Statement

ERA Ecological Risk Assessment

FA Fisheries Act

HAAT Habitat Alteration Assessment Tool

HADD Harmful Alteration, Disruption or Destruction of Fish Habitat

I&E Impingement and entrainment

LSA Local Study Area

MOE Ontario Ministry of Environment




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MWAT Maximum Weekly Average Temperature

WMHT Weekly Maximum Hourly Temperature

NND New Nuclear – Darlington

OMNR Ontario Ministry of Natural Resources

OPG Ontario Power Generation Inc.

Project The Site Preparation, Construction and Operation and Maintenance of New

Nuclear - Darlington

R+R Radiation and Radioactivity Environment

RSA Regional Study Area

SSA Site Study Area

SWE Surface Water Environment

SWM Stormwater Management

TSD Technical Support Document

USEPA United States Environmental Protection Agency

VEC Valued Ecosystem Component

YOY Young of Year Fish

Glossary of Terms

Aboriginal Rights: Those rights of Aboriginal Peoples which are not found in treaties or

land claim agreements.

Adaptive Management

Plan:

It is the integration of design, management, and monitoring to

systematically test assumptions in order to adapt and learn.

Aquatic Environment: The components related to, living in, or located in or on water or the

beds or shores of a water body, including but not limited to all

organic and inorganic matter, and living organisms and their habitat,

including fish habitat, and their interacting natural systems.

Baseload: The minimum amount of electric power delivered or required at a

steady rate over a given period of time.

Boiler: A device for generating steam for power, processing, or heating

purposes, or for producing hot water for heating purposes or hot

water supply. Heat from an external combustion source is

transmitted to a fluid contained within the tubes in the boiler shell.

This fluid is delivered to an end-use at a desired pressure,




vii

temperature, and quality.

Conservation: Steps taken to cause less energy to be used than would otherwise be

the case. These steps may involve improved efficiency, avoidance of

waste, reduced consumption, etc. They may involve installing

equipment (such as a computer to ensure efficient energy use),

modifying equipment (such as making a boiler more efficient),

adding insulation, changing behaviour patterns, etc.

Ecological Risk

Assessment:

The process that evaluates the likelihood that adverse ecological

effects may occur or are occurring as a result of exposure to one or

more stressors. This definition recognizes that a risk does not exist

unless: (1) the stressor has an inherent ability to cause adverse

effects, and (2) it is coincident with or in contact with the ecological

component long enough and at sufficient intensity to elicit the

identified adverse effects(s).

Efficiency: The efficiency of a generating unit in converting the thermal energy

contained in a fuel source to electrical energy. It is expressed as a

percentage and equals 3.6 divided by the heat rate of the unit (in

GJ/MWh).

Electrical Power: The rate of delivery of electrical energy and the most frequently used

measure of capacity. The typical basic units of electrical power are

the kilowatt (kW) and megawatt (MW).

Energy: The capability for doing work (potential energy) or the conversion of

this capability to motion (kinetic energy). Energy has several forms,

some of which are easily convertible and can be changed to another

form useful for work. Most of the world’s convertible energy comes

from fossil fuels that are burned to produce heat that is then used as

a transfer medium to mechanical or other means in order to

accomplish tasks.

Entrainment: Occurs when aquatic invertebrates, fish eggs and fish larvae are

drawn into a water intake and cannot escape.

Environmental

Assessment:

A process for identifying project and environment interactions,

predicting environmental effects, identifying mitigation measures,

evaluating significance, reporting and following-up to verify

accuracy and effectiveness. Environmental Assessment is used as a

planning tool to help guide decision-making, as well as project

design and implementation.




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Environmental Effect: As defined in the Canadian Environmental Assessment Act.

Exclusion Zone: A parcel of land within or surrounding a nuclear facility on which

there is no permanent dwelling and over which a licensee has the

legal authority to exercise control (from Class I Nuclear Facilities

Regulations).

Facility: An existing or planned location or site at which prime movers,

electric generators, and/or equipment for converting mechanical,

chemical, and/or nuclear energy into electric energy are, or will be,

situated. A facility may contain generating units of either the same

or different prime mover types.

Fuel: Any substance that can be burned to produce heat. It is also a

material that can be fissioned in a nuclear reaction to produce heat.

Generating Unit: Any combination of physically connected reactor(s), boiler(s),

combustion turbine(s), or other prime mover(s), generator(s), and

auxiliary equipment operated together to produce electricity.

Generating Plant: A facility containing one or more generating units.

Generation: The process of producing electrical energy by transforming other

forms of energy.

Impingement: Occurs when an entrapped fish is held in contact with the intake

screen and is unable to free itself.

In Situ: In its original place; in position; in situ recovery refers to various

methods used to recover deeply buried bitumen deposits, including

steam injection, solvent injection, and firefloods.

Joint Review Panel: A Review Panel appointed pursuant to the Canadian Environmental

Assessment Act.

Kilowatt (kW): A standard unit used to measure electric power, equal to 1,000 watts.

A kilowatt can be visualized as the total amount of power required to

light ten 100-watt light bulbs.

Local Study Area

(LSA):

Land and portions of Lake Ontario beyond the SSA where there is a

reasonable potential for obvious, readily-understood and mitigable

environmental effects related to the Project.




ix

Megawatt (MW): One million watts.

Nuclear Power Plant: A generating plant in which heat produced in a nuclear reactor by

the fissioning of nuclear fuel is used to drive a steam turbine.

Porous Veneer Intake: A specially designed water intake, which incorporates fish protection

features, for delivery of cooling water to the power plant.

Project: Site Preparation, Construction and Operation of New Nuclear –

Darlington (NND).

Proponent: Ontario Power Generation Inc. (OPG).

Radioactive nuclides /

radionuclides:

Is an atom with an unstable nucleus. The radionuclide undergoes

radioactive decay by emitting a gamma ray(s) and/or subatomic

particles. Radionuclides are often referred to by chemists and

biologists as radioactive isotopes or radioisotopes, and play an

important part in the technologies that provide us with food, water

and good health. Radionuclides may occur naturally, but can also be

artificially produced.

Regional Study Area

(RSA):

Land and portions of Lake Ontario beyond the LSA that could

reasonably be considered relevant in the assessment of more wide-

spread environmental effects, and wherein there is a potential for

cumulative and socio-economic effects related to the Project.

Site Study Area (SSA): The property, including land and portions of Lake Ontario, on which

the Project is located and which is under the care and control of

OPG; plus those adjacent areas that are clearly associated with it as a

result of biophysical connection.

Species at Risk: As defined in the federal Species at Risk Act.

Sustainability: Indicator selected with the aim to provide information on the essence

of sustainable development; it may refer to systemic characteristics

such as carrying capacities of the environment, or it may refer to

interrelations between economy, society, and the environment.

Terrestrial

Environment:

The components related to, living on, or located on the Earth’s land

areas, including but not limited to all organic and inorganic matter,

living organisms and their habitat, and their interacting natural

systems.




x

Thermal Discharge

(Diffuser):

Discharge of waste heat to the lake environment using a specially

designed pipe with diffuser ports to minimize impacts to the

environment.

Turbine: A machine for generating rotary mechanical power from the energy

of a stream of fluid (such as water, steam, or hot gas). Turbines

convert the kinetic energy of fluids to mechanical energy through the

principles of impulse or reaction, or a mixture of the two.




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LIST OF TECHNICAL SUPPORT DOCUMENTS (TSDs)

Atmospheric Environment Existing Environmental Conditions TSD – SENES Consultants Limited

Atmospheric Environment Assessment of Environmental Effects TSD – SENES Consultants Limited

Surface Water Environment Existing Environmental Conditions TSD – Golder Associates Limited

Surface Water Environment Assessment of Environmental Effects TSD – Golder Associates Limited

Aquatic Environment Existing Environmental Conditions TSD – SENES Consultants Limited and Golder

Associates Limited

Aquatic Environment Assessment of Environmental Effects TSD - SENES Consultants Limited and Golder

Associates Limited

Terrestrial Environment Existing Environmental Conditions TSD – Beacon Environmental

Terrestrial Environment Assessment of Environmental Effects TSD – Beacon Environmental

Geological and Hydrogeological Environment Existing Environmental Conditions TSD – CH2M HILL Canada

Limited and Kinectrics Incorporated

Geological and Hydrogeological Environment Assessment of Environmental Effects TSD – CH2M HILL Canada

Limited

Land Use Existing Environmental Conditions TSD – MMM Group Limited

Land Use Assessment of Environmental Effects TSD – MMM Group Limited

Traffic and Transportation Existing Environmental Conditions TSD – MMM Group Limited

Traffic and Transportation Assessment of Environmental Effects TSD – MMM Group Limited

Radiation and Radioactivity Environment Existing Environmental Conditions TSD – AMEC NSS

Radiation and Radioactivity Environment Assessment of Environmental Effects TSD – SENES Consultants Limited

and AMEC NSS

Socio-Economic Environment Existing Environmental Conditions TSD - AECOM

Socio-Economic Environment Assessment of Environmental Effects TSD - AECOM

Physical and Cultural Heritage Resources Existing Environmental Conditions TSD – Archaeological Services

Incorporated

Physical and Cultural Heritage Resources Assessment of Environmental Effects TSD – Archaeological Services

Incorporated

Ecological Risk Assessment and Assessment of Effects on Non-Human Biota TSD – SENES Consultants Limited

Scope of Project for EA Purposes TSD – SENES Consultants Limited

Emergency Planning and Preparedness TSD – SENES Consultants Limited and KLD Associates Incorporated

Communications and Consultation TSD – Ontario Power Generation Incorporated

Aboriginal Interests TSD – Ontario Power Generation Incorporated

Human Health TSD – SENES Consultants Limited

Malfunctions, Accidents and Malevolent Acts TSD – SENES Consultants Limited

Nuclear Waste Management TSD – Ontario Power Generation Incorporated




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1. INTRODUCTION

1.1 Background

Ontario Power Generation (OPG) was directed by the Ontario Minister of Energy in June 2006

to begin the federal approvals process, including an environmental assessment (EA), for new

nuclear units at an existing site. OPG initiated this process, and in September 2006 submitted an

application for a Licence to Prepare Site the Canadian Nuclear Safety Commission (CNSC) for a

new nuclear power generating station at the Darlington Nuclear site (DN site), located in the

Municipality of Clarington on the north shore of Lake Ontario in the Region of Durham. The

DN site is currently home to Darlington Nuclear Generating Station (DNGS), a 4-unit plant, the

first unit of which was commissioned by OPG in 1990. It remains under OPG ownership and

operational control.

Before any licensing decision can be made concerning the new nuclear generating station, an EA

must be performed to meet the requirements of the Canadian Environmental Assessment Act(CEAA) and be documented in an Environmental Impact Statement (EIS). An EIS is a document

that allows a Joint Review Panel, regulators, members of the public and Aboriginal groups to

understand the Project, the existing environment and the potential environmental effects of the

Project. Guidelines for the preparation of the EIS were prepared by the Canadian Environmental

Assessment Agency (the CEA Agency) and the CNSC (in consultation with Department of

Fisheries and Oceans Canada (DFO), the Canadian Transportation Agency and Transport

Canada). The Guidelines require that the proponent prepare the EIS and support it with detailed

technical information which can be provided in separate volumes. Accordingly, OPG has

conducted technical studies that will serve as the basis for the EIS. These technical studies are

documented in Technical Support Documents (see Section 1.2 below).

1.1.1 The New Nuclear - Darlington Project

New Nuclear Darlington (NND), a new generating station, is proposed to be located primarily on

the easterly one-third (approximately) of the DN site, with reactor buildings and other related

structures located south of the Canadian National Railway Company (CN) rail line. The

proposed Project involves the construction and operation of up to four nuclear reactor units

supplying up to 4,800 MW of electrical capacity to meet the baseload electrical requirements of

Ontario. The proposed Project will include:

Preparation of the DN site for construction of the new nuclear facility;

Construction of the NND nuclear reactors and associated facilities;

Construction of the appropriate nuclear waste management facilities for storage and

volume reduction of waste;

Operation and maintenance of the NND nuclear reactors and associated facilities for

approximately 60 years of power production (i.e., for each reactor);

Operation of the appropriate nuclear waste management facilities; and,

Development planning for decommissioning of the nuclear reactors and associated

facilities, and eventual turn-over of the site to other uses.




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For EA planning purposes, the following temporal framework has been adopted for the Project:

Project Phase Start Finish

Site Preparation and Construction 2010 2025

Operation and Maintenance 2016 2100

Decommissioning and Abandonment 2100 2150

1.1.2 The New Nuclear - Darlington Environmental Assessment

The EA considers the three phases of the NND Project (i.e., Site Preparation and Construction,

Operation and Maintenance, and Decommissioning and Abandonment) extending over

approximately 140 years. In doing so, it addresses:

The need for, and purpose of the Project;

Alternatives to the Project;

Alternative means of carrying out the Project that are technically and economically

feasible, and the environmental effects of such alternatives;

The environmental effects of the Project including malfunctions, accidents and

malevolent acts, and any cumulative effects that are likely to result from the Project in

combination with other projects or activities that may be carried out;

Measures to mitigate significant adverse environmental effects that are technically and

economically feasible;

The significance of residual (after mitigation) adverse environmental effects;

Measures to enhance any beneficial environmental effects;

The capacity of renewable resources that are likely to be significantly affected by the

project, to meet the needs of the present and the future;

The requirements of a follow-up program in respect of the Project;

Consideration of community knowledge and Aboriginal traditional knowledge; and,

Comments that are received during the EA.

1.2 Technical Support Document (TSD)

The EA studies were carried out and are documented within a framework of individual aspects or

“components” of the environment. The environmental components are:

Atmospheric Environment;

Surface Water Environment (SWE);

Aquatic Environment (AE);

Terrestrial Environment (TE);

Geological and Hydrogeological Environment;

Land Use;

Traffic and Transportation;

Radiation and Radioactivity Environment (R+R);

Socio-Economic Environment;




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Physical and Cultural Heritage Resources;

Aboriginal Interests;

Health - Human; and,

Health – Non-Human Biota (Ecological Risk Assessment).

This Technical Support Document (TSD) describes the assessment of effects of the Project on

the aquatic component of the environment. It has been prepared by Golder Associates and

SENES Consultants Limited, the member firm of the EA Consulting Team with technical

responsibility for the AE component of the environment. This TSD is one of a series of related

documents describing different aspects of the overall effects assessment, one for each

environmental component.

A separate series of TSDs (i.e., Existing Environmental Conditions TSDs), one for each

environmental component, describes the baseline conditions throughout the study areas relevant

to the Project, including Valued Ecosystem Components (VECs). A preliminary screening of

potential Project-environment interactions for each environmental component was carried out

during the baseline characterization program to focus those studies on relevant aspects of the

existing environment.

In most cases, separate TSDs have been prepared to describe existing conditions and likely

effects of the Project. However, for some environmental components the description of existing

environmental conditions and the assessment of environmental effects have been combined

within one TSD.

A number of other TSDs have also been prepared to address related subjects in support the EA.

These include, but are not necessarily limited to:

Scope of the Project for EA Purposes;

Emergency Planning and Preparedness;

Communications and Consultation;

Malfunctions, Accidents and Malevolent Acts; and,

Nuclear Waste Management.

1.3 Description of the Aquatic Environment Component

The AE is defined as aquatic habitat and aquatic biota. It is comprised of the following

environmental subcomponents that represent fundamental constituent features that are potentially

susceptible to effects of the Project and/or are pathways or mechanisms for transfer of an effect

to another environmental component. Aquatic habitat and aquatic biota are defined as:

Aquatic habitat includes the physical areas of Lake Ontario, tributary watercourses and

ponds within the study area. In these different areas, it is characterized by conditions of

flow, current, bathymetry, temperature, substrates, and water quality that influence its

status with respect to the Fisheries Act (FA) (DFO 1986) (i.e., whether it is fish habitat,




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and of what type). Because the areas occupied by existing and future intake forebays will be

artificially separated from Lake Ontario, they were not included in the assessment.

Aquatic biota includes the communities of underwater plants and animals that occupy

the aquatic habitat defined above. These include, depending on habitat conditions,

periphyton, aquatic macrophytes, phytoplankton, benthic invertebrates, zooplankton, and

fishes. Aquatic biota may also include rare, vulnerable, threatened and endangered

aquatic species.

(For this assessment, emphasis has been placed on interactions related to benthic

invertebrates and fish, as these organisms are integrators of a diverse range of

environmental conditions, their responses are generally understood and they tend to be

the subject of management and conservation objectives.)

(The effects of releases of potentially toxic substances is not addressed in this TSD, but

rather, are considered in the ERA – Environmental Effects Assessment TSD and the R+R

– Environmental Effects Assessment TSD.)

1.3.1 Aquatic Habitat VECs

Aquatic habitat VECs were chosen to focus the assessment on the Site Preparation and

Construction Phase of the Project works and activities that will result in alterations to on-site

drainage features and portions of the Lake Ontario nearshore. Agency review and permits will be

required, including Fisheries and Oceans Canada (DFO) or Central Lake Ontario Conservation

Authority (CLOCA) authorization and Ontario Ministry of Natural Resources (OMNR) permits,

so it is considered useful to discuss effects in the EA in habitat terms and to consider fish habitat

compensation requirements as the likely mitigation measures that will be required beyond those

already incorporated in the Project design as effects management features. It is too early in the

design process to define fish habitat effects of the Project in sufficient detail to completely

negotiate a section 35(2) FA authorization, which is required for works that will result in

Harmful Alteration, Destruction or Disruption of fish habitat (HADD). However, the DFO

framework to assess the HADD will follow the Policy for the Management of Fish Habitat (DFO

1986) and employ the Habitat Alteration Assessment Tool (HAAT) that is currently in use by

DFO for projects of large magnitude and is described by a series of habitat model research and

development papers that were prepared by DFO scientists (Minns et al. 1995, 2001; Minns

1997). The HAAT is a model that assigns productivity values, based on substrates, bathymetry

and other habitat parameters on an area basis, to affected fish habitat and also to the proposed

fish habitat compensation works that are intended to offset any losses. OPG and consultants are

currently in discussion with DFO and other stakeholders concerning fish habitat losses and

credible compensation options have been identified.

The assessment must be prefaced with a detailed description of the design, engineering, public

safety and nuclear safety constraints and considerations that led to the proposed design and made

the in-water works an unavoidable part of the Project. The habitat VECs are described as

follows:




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Darlington Creek and Darlington Creek Tributary Habitat – consists of the main branch

of Darlington Creek that crosses the northeast corner of the site and continues east of the

site boundary to where it joins Lake Ontario. Darlington Creek is a permanent fish habitat

with resident fish and invertebrate species and also a migratory community that accesses

the creek seasonally from Lake Ontario. Tributary habitat consists of the intermittent

watercourses that drain eastward from the site across the east site boundary to meet the

main branch of Darlington Creek. One tributary is located north of the CN rail line, in the

proposed soil disposal area. The other tributary is located south of the CN rail line, within

the proposed NND station site footprint. The portions of the intermittent tributaries on the

DN site do not possess the types of habitat that directly support fish or aquatic

invertebrates, but flow from the tributaries contributes to aquatic habitats downstream.

They would therefore be considered “indirect” or “contributing” fish habitat by DFO.

The indicator species and selected for this VEC is white sucker, described below.

Lake Ontario Nearshore Habitat – consists of the shallow areas of Lake Ontario adjacent

to the site and along the north shore, extending out to approximately 30 meters depth.

The Lake Ontario nearshore is an important habitat for many fish species, including

warmwater fish that venture out of bays, marshes and tributaries when nearshore water

temperatures are favourable, and also coldwater fish that move inshore from the open

lake to feed, spawn on shoals or run up tributaries to spawn. The nearshore is a dynamic

environment that produces attached algae, benthic invertebrates, phytoplankton and

zooplankton. The ten indicator species and groups selected for this VEC are the same as

those selected for the aquatic biota VECs and are described below.

1.3.2 Aquatic Biota VECs (Forage Species, Benthivorous Fish and Predatory Fish)

Species or groups of species were chosen as suitable indicators of habitat change. Selection of

indicator species provides for use of specific measures to assess habitat change by focusing the

assessment on receptors with known affinity to the nearshore, history of interaction with nuclear

generating facilities such as DNGS, or particular conservation concern. The Project will interact

with various species in accordance with characteristics such as habitat preferences,

ecological/foraging niche, migratory behaviour, and location of critical habitats (e.g., spawning

and nursery areas). There are many species in Lake Ontario, so the VEC indicator species were

considered according to general trophic web groupings, namely the VECs: forage species,

bottom-feeding or benthivorous species and fish-eating predators or piscivorous species. This

approach was considered less confusing and arbitrary than trying to define “resident” and

“migratory” groups of species from which to choose VEC indicator species, since both use

nearshore habitats and migrate to varying degrees. Further, the trophic approach is relevant to the

ERA which is being conducting as part of the EA and considers the uptake and transfer of

contaminants among trophic levels. The VEC indicator species are described below.

Benthic Invertebrates – comprise a community of species including aquatic worms,

insects, crustaceans, snails and mussels that live within or on top of the lake bed

substrates. Benthic invertebrates are important food items for many fish species and for

wildlife such as diving ducks, which forage directly in benthic habitats and bank




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swallows, which forage indirectly on benthos in the form of flying adult insects that

develop from benthic larvae;

Round goby – is an exotic invasive fish species that has spread throughout much of the

Great Lakes and has become an important prey species in the Lower Great Lakes. The

round goby is resident in nearshore Lake Ontario habitats, and is one of the dominant fish

species at DNGS based on 2009 surveys;

Emerald shiner – is an abundant schooling minnow that is native to the Great Lakes, and

frequents the nearshore for spawning and feeding. It is an important forage species;

Alewife – is a schooling member of the herring family that was introduced to the Great

Lakes. Alewife are highly migratory and range throughout the entire lake. A single

alewife population occupies Lake Ontario and this species remains the most numerous

and important forage fish despite recent declines related to changes in the Lake Ontario

food web. The alewife moves inshore in the summer to spawn. It is also the dominant

species impinged at DNGS, and along with round goby, one of the dominant species

collected based on 2009 gillnetting surveys;

White sucker – is a bottom-dwelling native fish that feeds on benthic invertebrates and is

resident as adult fish in the nearshore of Lake Ontario. White sucker ascend tributary

streams to spawn, such as Darlington Creek. Adults return to the lake after spawning.

Eggs, larvae and early life stages of white sucker remain in the spawning streams before

returning to the lake;

Round whitefish – is a bottom-dwelling native coldwater fish that moves inshore to feed

and spawn when nearshore waters cool in October and November. Round whitefish

include the nearshore in their foraging ranges during the fall, winter and early spring

when water temperatures are low. Round whitefish eggs remain in nearshore substrates

over the winter and hatch in the spring, after which the young-of-the-year (YOY) fish

begin feeding in the nearshore and gradually move offshore as they grow;

Lake sturgeon – is a bottom-dwelling native benthivorous fish that was once very

common and abundant in the Great Lakes but was decimated by overfishing and habitat

destruction. A long-lived and slow-maturing species, it has shown recent signs of limited

recovery with the appearance of greater numbers of juvenile sturgeon in nearshore areas,

including the areas near the DN site. Recovery of the lake sturgeon population is a

conservation objective shared by Canadian and American agencies;

American eel – is a bottom-dwelling native predator that was encountered frequently

during a study of nearshore habitat at the DN site (Tarandus 1998). American eel has

become the focus of conservation concern in recent years as this once-abundant fish has

declined substantially across much of its range. Habitat in the vicinity of the DN site

represents foraging areas for adult eels;

Lake trout – is a bottom-oriented predatory salmonid. The original Lake Ontario stock of

this species was extirpated and the existing lake trout population is the result of stocking

of hatchery-reared fish derived from Georgian Bay / Lake Huron stocks. Lake trout

reproduction in the lake remains low, and stocking continues to support the current

population. As coldwater migratory fish, lake trout spend much of the year offshore.

Tagging studies have shown that individual fish migrate extensively throughout the lake.

Lake trout move inshore to spawn and feed when nearshore water temperatures are low in

the fall and early winter. Lake trout forage in the nearshore in fall, winter and early spring




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when water temperatures are low. Lake trout eggs overwinter on nearshore shoals and

juvenile trout begin life in the nearshore prior to moving into deeper waters; and,

Salmonid sport fish – comprise several species of introduced trout and salmon that are the

focus of recreational or sport fishing and that are maintained partially or in large measure

by stocking. These species are migratory open-water fish that forage in Lake Ontario but

ascend tributary streams to spawn. These include brown and rainbow trout and coho and

chinook salmon. Atlantic salmon, the original Lake Ontario stock of which was

extirpated by overfishing and damming of spawning tributaries, is the subject of repeated

reintroduction efforts using stocked fish, but has not flourished to date. Lake trout could

be included in this VEC category, but are treated separately because they are not a

favoured species of sport fisherman on the Lake Ontario north shore and because they

spawn in the nearshore and therefore have the potential to interact with the Project in the

context of spawning and recruitment success.

VECs and the indicator species are discussed in the following sections in relation to those Project

works and activities with which they are likely to interact.




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2. EFFECTS ASSESSMENT METHODOLOGY

At the time of completing this TSD, three vendors were being considered by the Province of

Ontario for supplying and installing the reactors and associated equipment for the Project.

Accordingly, the specific reactor to be constructed and operated had not yet been determined.

Therefore, for purposes of the EA, the Project was defined in a manner that effectively

incorporated the salient aspects of all of the considered reactors. Similarly, the existing

environmental conditions and the likely environmental effects of the Project were also

determined in a manner that considered the range of reactor types and number of units that may

comprise the Project.

The essential aspect of the method adopted for defining the “Project for EA Purposes” is the use

of a bounding framework that brackets the variables to be assessed. This bounding framework is

defined within a Plant Parameter Envelope (PPE). The PPE is a set of design parameters that

delimit key features of the Project. The bounding nature of the PPE allows for appropriate

identification of a range of variables within a project for the purpose of the environmental

assessment while also recognizing the unique features of each design. For further information

concerning the use of the PPE for this EA, the reader is directed to Section 2.1 of the EIS.

The information presented in this TSD is deemed to be appropriately bounding so as to facilitate

the assessment of environmental effects that may be associated with any of the considered

reactors. As both the EA studies and the vendor selection programs continue, it may be that

aspects of this TSD are updated to respond to these evolving programs, in which case the

updated information will be presented in an addendum to this TSD or in the EIS. The EIS itself

will remain subject to edits until it has been accepted by the JRP as suitable for the basis of the

public hearing that will be convened to consider the Project.

This TSD is a document prepared in support of the EIS. Where there may be differences in the

information presented in the two documents, the EIS will take precedence for the reasons noted

above.

2.1 Assessment Framework

Details of the EA process and the assessment methods used throughout the EA are described in

Chapter 3 of the Environmental Impact Statement (EIS). This TSD focuses specifically on the

assessment of effects of the Project on the environment and in doing so the following procedural

steps were applied:

Detailed screening for potential Project-environment interactions;

Identification of likely changes to the environment;

Identification and assessment of likely effects on the environment as a result of changes;

and,

Consideration of mitigation measures and determination of likely residual effects.

These steps are further described in Section 2.3.




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2.2 Assessment Basis, Spatial Boundaries, Methods and Criteria

2.2.1 Project Basis for the Assessment

A full description of the Project that is the subject of the EA is provided in the Scope of the

Project for EA Purposes TSD. A summary description of the specific works and activities that

collectively comprise the Project (i.e., Basis for the EA) is included in this TSD as Appendix A.

The Scope of the Project for EA Purposes TSD described four development scenarios and three

reactor operation scenarios. For the purpose of screening and assessment of Project interactions

with the AE, bounding scenarios were chosen for the Site Preparation and Construction Phase

and for the Operation and Maintenance Phase.

For the Site Preparation and Construction Phase, Site Development Scenario 1, Four ACR 1000

Reactors with Once-Through Cooling, was chosen as the bounding scenario as it would

encompass the maximum extent of in-water works that would affect aquatic habitat and aquatic

biota, including:

Bridge crossing (box culvert) of the main branch of Darlington Creek for heavy

construction equipment access;

Loss of Treefrog, Polliwog and Dragonfly ponds;

Alterations to site drainage, reuslting in the loss of portions of intermittent tributaries to

Darlington Creek;

Alteration/disruption of Coot’s Pond;

Realignment and possible loss of upper portions of an intermittent tributary to Lake

Ontario near Coot’s Pond;

Lake infill totalling approximately 40 hectares along approximately 2 kilometers of

shoreline in front of the DNGS and NND sites, including loss of habitat and alteration of

coastal processes;

Blasting and excavation in an area of approximately 1.1 hectares, as defined in the SWE -

Environmental Effects Assessment TSD required to construct the porous veneer once-

through Condenser Circulating Water (CCW) intake structure in an area approximately

100 meters across in at least 10 meters water depth approximately 850 meters offshore;

and,

Blasting and excavation required to install approximately 90 diffuser ports (cumulative

area of approximately 0.7 hectares) for the once-through CCW discharge structure on the

discharge tunnel along an alignment extending from approximately 870 m to 1,850 m

offshore, in 10-20 meters water depth.

For the Operation and Maintenance Phase, Reactor Operations Scenario 1, Four ACR-1000

Reactors, was chosen as the bounding scenario as it involves the once-through cooling water

system (approximately 230 m3/s) and service water requirements (approximately 20 m

3/s) which

involves a slightly higher rate of once-through CCW circulation than the other scenarios, based

on information provided in the Technical Support Document – Scope of the Project for EA




2-3

Purposes. The rate of once-through cooling water circulation is an important factor in the

assessment of the following key interactions:

Impingement and entrainment of aquatic organisms, particularly fish (adults, juvenile,

eggs and larvae); and

Thermal effects on habitat suitability and aquatic organisms.

For the purpose of the assessment, the bounding once-through CCW flow was assumed to be

250 m3/s, consistent with the SWE - Environmental Effects Assessment TSD. The intake

structure design was assumed to be a scaled-up version of the DNGS lakebottom porous veneer

intake as described in the SWE - Environmental Effects Assessment TSD. This design is expected

to achieve a mean water intake velocity (as permitted at DNGS) of less than 0.15 m/s at a

distance of 5 cm above the intake structure. Consistent with the SWE Effects Assessment, the

rate of circulation was assumed to maintain a maximum change in water temperature between

intake and discharge of 9oC and the resulting size and temperature characteristics of the

discharge mixing zone were considered as predicted by the SWE thermal plume model. An

alternative cooling scenario involving increased discharge water temperature of 15.6oC above

ambient was addressed in SWE - Environmental Effects Assessment TSD. SWE concluded that

although the discharge temperature would be higher, the combination of reduced flow

requirements and the function of the discharge diffuser would result in a similar mixing zone

area and similar temperature conditions to the 9oC option. Although higher temperatures would

occur at the diffuser ports, the mixing is expected to occur rapidly and over a short distance. The

discharge velocity and turbulence along the diffuser line makes it unlikely that aquatic organisms

would frequent the area or remain immediately in front of diffuser ports. As such, the 9oC

scenario was used as the basis of the assessment.

The cooling tower option requires intake of makeup and service water of only approximately

6 m3/s, compared with the 250 m

3/s once-through cooling flow. Although a porous-veneer intake

is not anticipated for the cooling tower intake, it will nevertheless include in-design mitigation

measures to limit fish losses. The cooling tower discharge structure will incorporate a (single-

port) diffuser to facilitate mixing. As such, the potential environmental effects of impingement

and entrainment, and thermal discharge, associated with the cooling tower option are considered

to be fully addressed within the once-through cooling bounding scenario.

2.2.2 Spatial Boundaries for the Assessment

Generic spatial boundaries (i.e., study areas) applied for the EA are described in the EIS in a

context of Site Study Area (SSA), Local Study Area (LSA) and Regional Study Area (RSA).

These generic study areas were considered for their specific relevance to the AE and modified as

appropriate to recognize the unique nature of this environmental component. The study areas

applied for this assessment, including the rationale for their delineation, are described below and

are illustrated in Figures 2.2-1, 2.2-2 and 2.2-3. Sampling locations for specific 2008 and 2009

studies involving fish habitat assessment of the proposed infill area, larval fish and adul fish

community studies and Darlington Creek habitat assessment are documented in the AE Existing

Environmental Conditions TSD.




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Site Study Area (SSA): the property, including land and portions of Lake Ontario, on

which the project is located and which is under the care and control of OPG; plus those

adjacent areas that are clearly associated with it as a result of biophysical connection (see

Figure 2.2-1);

Local Study Area (LSA): land and portions of Lake Ontario beyond the SSA where

there is a reasonable potential for obvious, readily-understood and mitigable

environmental effects related to the Project (see Figure 2.2-2); and,

Regional Study Area (RSA): land and portions of Lake Ontario beyond the LSA that

could reasonably be considered relevant in the assessment of more wide-spread

environmental effects, and wherein there is a potential for cumulative and socio-

economic effects related to the Project. The RSA is identical to the SWE RSA (see

Figure 2.2-3).

New Nuclear-Darlington Aquatic Environment



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2-6




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2.2.3 Analytical Methods for the Assessment

Assessment of effects across a wide range of environmental components and sub-components

requires the use of a variety of different analytical methods (e.g., computer models, manual

calculations, relevant project experiences, formal case studies, comparison against relevant

benchmarks, professional judgement). The specific methods used in the assessment of

environmental effects in the AE are as follows:

Site Preparation and Construction Phase activities will result in “Harmful Alteration,

Disruption or Destruction of Fish Habitat” (HADD) as defined by the section 35(2) of the

FA. The method of assessment related to this effect considered both the extent and

qualitative character of the affected habitats, including the role and importance of

affected habitats in the context of the Canadian fishery and the mitigation and

compensation strategies that will be required, in anticipation of the need for an

authorization under section 35(2) of the FA.

Site Preparation and Construction Phase development of the watercourse crossing at

Darlington Creek was assessed as similar to existing road crossings that used box culverts

and associated in-stream disturbance. The assessment also considered the DFO

Operational Statement for clear-span bridges (DFO 2007), and noted that construction of

a two-lane clear span crossing could avoid a HADD and the need for a section 35(2) FA

authorization.

Site Preparation and Construction Phase blasting activities required to complete the CCW

intake and discharge structures were assessed in consideration of the DFO “Guideline for

the Use of Explosives In or Near Canadian Fisheries Waters” (Wright and Hopky, 1998)

approach to design, mitigation and assessment in anticipation of necessity of an

authorization under section 32 of the FA.

Operation and Maintenance Phase once-through CCW fish impingement and entrainment

(I&E) losses were assessed using results of DNGS impingement and entrainment studies

as an applicable case study that is expected to approximate these effects at the NND.

DNGS is a relevant surrogate case as it shares the site with the Project and the Project

bounding scenario assumes a similar intake structure. In addition, recently collected

DNGS impingement and entrainment data was used to estimate losses that could be

associated with the NND. The cooling tower option was also assessed to determine I&E

losses that could be associated with the intake of make-up cooling and service water.

Operation and Maintenance Phase once-through CCW thermal discharge effects were

assessed by numerical modelling of the dispersal of heated water within Lake Ontario by

the SWE component. DNGS was adopted as a case study for the predicition of

anticipated thermal effects. DNGS is a relevant surrogate case as it shares the site with

the Project and the Project bounding scenario (once-through cooling) will employ a

similar diffuser structure with similar performance characteristics. The cooling tower

option thermal discharge was also assessed by SWE on the assumption that a single-port

diffuser would be installed to enhance mixing of heated water with ambient lake water.




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2.2.4 Criteria for the Assessment

The assessment of Project-related effects requires criteria that are relevant to protection and

conservation of various environmental components. For effects that relate to changes in aquatic

habitat, the area of habitat affected and the qualitative function of the habitat constitute the

criteria of assessment. These criteria, which can be summarized as habitat area and habitat

quality, are consistent with the approach to seeking authorization under section 35(2) of the FA.

For effects that relate to various aquatic species the criterion of assessment is population

conservation. In other words, the effects on biota are assessed for the likelihood of affecting

species at a population level that would be expected to measurably change populations and

possibly affect their viability. The criteria of assessment for the AE are further described in

Section 3.2.

2.3 Process Steps for Determination of Likely Environmental Effects

2.3.1 Detailed Screening for Potential Project-Environment Interactions

A preliminary screening for potential interactions was conducted during baseline characterization

studies to ensure appropriate focus of those studies. A more detailed screening was subsequently

conducted for each component of the environment based on the Description of the Project (as

summarized in the Basis for the EA in Appendix A) to direct the effects assessment effort. The

screening approach allows the EA studies to focus on the aspects of key importance, thus

minimizing assessment effort where there is low potential for Project-related effect.

Each of the relevant Project works and activities was considered individually to determine if

there was a plausible mechanism for the Project to interact with the environment.

2.3.2 Evaluation for Likely Measurable Changes in the Environment

Each potential interaction was evaluated to determine if it would be likely to result in a

“measurable” change to the environment. These changes are summarized in Table 2.3.2-1,

below. For purposes of the EA, a measurable change to the environment is defined as a change

that is real, observable or detectable compared with existing (baseline) conditions. A predicted

change that is trivial, negligible or indistinguishable from background conditions is not

considered to be measurable.




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TABLE 2.3.2-1

Range and Relevance of Potential Change in the AE

Project

Phase/Activity

Effect and

Environmental

Subcomponent

Assessment

CriteriaRange and Relevance of Potential Change

Site Preparation and

Construction –

Mobilization and

Preparatory Works

(Site Clearing),

Excavation and

Grading,

Management of

Stormwater

Loss/alteration of

ponds, creeks and

intermittent

tributaries

Habitat and biotic

community

quality and extent

(area or length)

Primary effects limited to SSA and are considered

low due to scope of restoration. Indirect effects to

LSA or RSA are considered low due to scope for

on-site restoration and limited connectivity of on-

site aquatic habitats to Lake Ontario or adjacent

watersheds.


Construction –

Marine and

Shoreline Works

(Lake infill and

Shoreline

Stabilization),

Management of

Stormwater

Loss/alteration of

nearshore Lake

Ontario habitat

Direct loss of fish

and invertebrates

Habitat extent

and function

relevant to Lake

Ontario aquatic

biota populations

Likelihood of

losses to affect

fish populations

Direct effects limited to SSA, with low potential for

population-level effects on LSA and RSA level due

to small proportion affected of available similar

habitat.

Direct loss of fish and invertebrates limited to the

SSA and mitigated by fish salvage where

practicable.


Construction –

Intake and Diffuser

Loss/alteration of

nearshore Lake

Ontario habitat

Direct loss of fish

and invertebrates

Habitat extent

and function

relevant to Lake

Ontario aquatic

biota populations

Likelihood of

losses to affect

fish populations

Direct effects limited to SSA, with low potential for

population-level effects on LSA and RSA due to

small proportion affected of available similar

habitat.

Direct blasting effects limited to small proportion of

SSA with low fish density and therefore low

likelihood of mortality that could affect

populations.

Operation and

Maintenance –

Operation of

Condenser

Circulating Water,

Service Water and

Cooling Systems -

Intake Cooling

Water

Fish

impingement

(eggs, larvae)

Likelihood of

losses to affect

fish populations

Direct effects limited to fish within the SSA. LSA

and RSA effects possible due to fish migration, but

considered low due to effective mitigation provided

by intake placement and design.

Fish and

invertebrate

entrainment

Likelihood of

losses to affect

fish, invertebrate

and plankton

populations

Direct effects limited to fish, invertebrates and

plankton within the SSA. Effects may extend to

LSA and RSA due to migration and transport of

biota by currents, but considered low due to

mitigation provided by intake placement and

design, low susceptibility of benthos, as well as low

proportion of plankton population entrained and

population-level compensatory mechanisms of fast-

reproducing plankton.




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Project

Phase/Activity

Effect and

Environmental

Subcomponent

Assessment

CriteriaRange and Relevance of Potential Change

Operation and

Maintenance –

Operation of

Condenser

Circulating Water,

Service Water and

Cooling Systems -

Discharge Thermal

Effluent

Thermal effects

on nearshore

habitat suitability

and fish species

Extent and

behaviour of

thermal plume

(modelling by

SWE component)

in relation to

preferred,

Maximum

Weekly Average

Temperature

(MWAT),

Weekly Hourly

Maximum

Temperature

(WHMT) and

lethal

temperatures

Direct effects limited to diffuser area in SSA and

extent of thermal plume in SSA and LSA. Low

potential for indirect population-level effects in

RSA due to mitigation of unnatural thermal

conditions by the diffuser. Relevance of thermal

conditions based on preferred temperature ranges of

nearshore and pelagic fish species, MWATs,

WMHT, and lethal temperatures as applicable, in

context of net effect on populations.

2.3.3 Assessment of Likely Effects on the Environment

Each Project interaction likely to result in a measurable change to the environment was further

evaluated to identify the likely effect of the change on a Valued Ecosystem Component (VEC)

selected for the AE, or on a pathway to other environmental components. VECs relevant to the

AE are described in the AE - Existing Environmental Conditions TSD.

Each likely effect was identified and described as either beneficial or adverse. Where the likely

effect was determined to be beneficial, no further assessment was conducted. Similarly, where

the likely effect was determined to be adverse, but clearly not of concern, no further assessment

was conducted. Rationale was provided in each case where further assessment was not

considered to be warranted. All other likely adverse environmental effects were carried forward

for consideration of mitigation opportunities.

2.3.4 Consideration of Mitigation and Determination of Likely Residual Effects

For each likely adverse effect (other than those clearly of no concern), possible means that were

technically and economically feasible were identified and considered for mitigating (i.e.,

eliminating, reducing or controlling) the effect. Each likely adverse effect was re-evaluated

assuming implementation of the identified mitigation measures, to determine the residual effect

that would remain after mitigation.

By advancing through the assessment in the methodical manner described above, the wider range

of potential Project-environment interactions identified at the beginning of the process was

progressively screened and evaluated to result in a narrower range of residual adverse effects

identified as likely at the end of the process. This progression from potential interactions

through to likely residual adverse effects is an important aspect of the overall assessment




2-12

methodology used, especially as it relates to the subsequent determination of significance of the

likely residual adverse effects.

Data has been summarized in the AE Existing Conditions TSD. Summary statistics used in this

report depend on a number of factors including but not limited to:

Regulatory requirements;

Precedence;

Professional judgment;

The creation of bounding scenarios or conservatism;

Use by and consistency with another environmental component; and/or,

Use in ongoing baseline monitoring.




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3. ASSESSMENT AND MITIGATION OF ENVIRONMENTAL EFFECTS

This section of the TSD describes the assessment conducted to determine the likely adverse

effects of the Project on the environment, and more specifically, on the VECs selected as

features of the AE to be the focus of the EA. The process followed in carrying out the

assessment is described in Chapter 2.

An evaluation of the significance of the residual adverse effects of the Project on the

Environment is presented collectively for all likely environmental effects in all relevant

environmental components, in the EIS.

3.1 Detailed Screening for Potential Project-Environment Interactions

Each Project work and activity (see Appendix A) was screened to consider if there was a

plausible mechanism or pathway by which it could interact with the AE. The screening

decisions were based on existing site information, knowledge of the environmental interaactions

at DNGS and other facilities, and the experience and professional judgment of the EA

biologists. Where no pathways were identified to the AE for a particular work or activitiy, these

were not considered further in the evaluation of effects on the AE. The results of the AE

screening and the rationale associated with each work and activity are summarized in

Table 3.1-1, below.

The Aquatic Environment comprises two environmental sub-components: Aquatic Habitat and

Aquatic Biota. The assessment addressed two primary effects (i.e., direct) pathways;

specifically, physical changes to aquatic habitat, and organism-level effects involving intake

losses and thermal discharge. Potential effects on non-human biota, including in the Aquatic

Environment, as a result of exposures to radiological and conventional constituents from NND

are evaluated in the Ecological Risk Assessment and Assessment of Effects on Non-Human

Biota TSD. Potential effects on water quality are briefly addressed in this document for

clarification purposes and expanded upon in the SWE - Assessment of Environmental Effects

TSD.




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TABLE 3.1-1

Potential Project-Environment Interactions in the AE

AE

Project Works and Activities

Ha

bit

at

Bio

ta

Rationale

SITE PREPARATION AND CONSTRUCTION PHASE

Mobilization and Preparatory Works

Clearing and grubbing will remove on-site ponds and approximately 400-meters of the

uppermost portions of two intermittent tributaries to Darlington Creek located on the east

side of the site.

Construction access road will cross Darlington Creek.

Interactions with the AE may occur through erosion and sedimentation (i.e., that directly

interact with the Surface Water environment). The potential interactions from this Project

Work and Activity and the Surface Water Environment and thus potential interactions with

the Aquatic Environment are captured in the Management of Stormwater Activity.

Excavation and Grading

Coot’s Pond may be altered or disrupted, with site restoration to follow.

Upper reaches of a Lake Ontario intermittent tributary near Coot’s Pond may be realigned

and/or reduced.

Interactions with the AE may occur through erosion and sedimentation (i.e., that directly

interact with the Surface Water environment). The potential interactions from this Project

Work and Activity and the Surface Water Environment and thus potential interactions with

the Aquatic Environment are captured in the Management of Stormwater Activity.

Areas dependent on groundwater discharge to the east of the site (i.e., Darlington Creek), if

present, will be minimally affected by the dewatering of the site

Marine and Shoreline Works

40 hectare lake infill, including construction of the wharf.

Blasting and excavation of intake (1.1 hectares) and diffuser (0.7 hectare) structures could

result in incidental mortality of fish and invertebrates.

Development of Administration and

Physical Support Facilities

Interactions with the AE may occur through erosion and sedimentation. The potential

interactions from this Project Work and Activity and the Surface Water Environment and

thus potential interactions with the Aquatic Environment are captured in the Management

of Stormwater Activity.

Construction of the Power Block








3-3

AE


Ha

bit

at

Bio

ta

Rationale

Construction of Intake and Discharge

Structures

Blasting and excavation of intake (1.1 hectares) and diffuser (0.7 hectare) structures could

result in the loss of a small area of potential fish habitat in the footprints of both the intake

and discharge structures.

Underwater blasting would result in incidental mortality of fish and invertebrates (in

localized area).

Construction of Ancillary Facilities





Construction of Radioactive Waste

Storage Facilities





Management of Stormwater

As the site is developed, ditches and swales will be constructed to collect and convey

surface water to stormwater management ponds and ultimately discharge to an existing

drainage course or Lake Ontario.

Potential beneficial effect of stormwater management facilities once design modifications

are implemented.

Supply of Construction Equipment

and Material and Plant Operating

Components





Management of Construction Waste,

Hazardous Materials, and Fuels and

Lubricants

No direct pathway to AE.

No plausible interaction as secondary containment of storage tanks (e.g., fuel oil) will be

provided to contain any releases from spillage or tank rupture.

This activity does not include the disposal of excavated soil (see Excavation and

Grading).

Workforce, Payroll and Purchasing No direct pathway to AE.




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AE


Ha

bit

at

Bio

ta

Rationale

OPERATION AND MAINTENANCE PHASE

Operation of Reactor Core

No direct pathway to the AE. Under normal operating conditions, the operation of the

reactor core does not directly interact with any subcomponent of the Surface Water

Environment, and thus does not interact with any subcomponent of the Aquatic

Environment.

Operation of Primary Heat Transport

System No direct pathway to the AE.

Operation of Active Ventilation and

Radioactive Liquid Waste

Management Systems

No direct pathway to the AE.

Operation of Safety and Related

Systems No direct pathway to the AE.

Operation of Fuel and Fuel Handling


Operation of Secondary Heat

Transport System and Turbine

Generators


Intermittent releases of Steam Generator blowdown will be tested and treated if necessary

to comply with the appropriate criteria for surface water discharge to Lake Ontario.

Operation of Condenser Circulating

Water, Service Water and Cooling

Systems

Impingement and entrainment of aquatic organisms.

Thermal effects on aquatic habitat and aquatic organisms through discharge of cooling

water.

Operation of Electrical Power


Operation of Site Services and

UtilitiesNo direct pathway to the AE.

Management of Operational Low and

Intermediate-Level Waste No direct pathway to the AE.

Transportation of Operational Low

and Intermediate-Level Waste to a

Licensed Off-site Facility


Dry Storage of Used Fuel No direct pathway to the AE.




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AE


Ha

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at

Bio

ta

Rationale

Management of Conventional Waste

No direct pathway to the AE. No plausible interaction as non-hazardous and non-

radioactive liquid wastes will be controlled in accordance with provincial waste

management regulations and provincial C of A requirements respectively.

Replacement / Maintenance of Major

Components and Systems

Potential direct pathway to the AE. There would likely be a reduction in the number of

fish impinged/entrained with reduced flows during a major refurbishment. However, once

the refurbishment is complete, impingement and entrainment would likely return to

previous levels. Other interactions with aquatic habitat and biota unlikely as the effects on

subcomponents of the SWE (namely water temperature and water quality) are not

expected. If refurbishment or maintenance activities result in the shutdown of one or

more reactors, the liquid effluents from these systems will be treated sufficiently as per

applicable legislation (e.g., C of A, MISA).

Physical Presence of the Station The Physical Presence of the Station is not considered to have the potential to interact

with the AE.

Administration, Purchasing and

Payroll No direct pathway to the AE.

Note:

A dot ( ) in the table grid indicates a potential Project-Environment interaction.




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3.2 Evaluation for Likely Change to the Environment

Each work and activity identified above in Table 3.1-1 as potentially interacting with the

environment was further evaluated to determine if it would be likely to result in a measurable

change to the sub-components of the AE. The evaluation considered the professional judgement

of the assessment team and quantifiable evaluation criteria as appropriate.

The criteria applied within the AE for evaluation of likely change in the environment (as well as

for the subsequent assessment of effects of any changes) are described in Table 3.2-1.

With respect to aquatic habitat, evaluation criteria are habitat quantity and quality, which

integrate aspects of habitat productivity. These parameters will be important to agency

stakeholders, such as DFO, and will guide the development of mitigation measures and fish

habitat compensation. DFO’s approach to the assessment, of the lake infill area in particular, will

require the use of the HAAT, which models and estimates the balance of fish productivity loss or

gain and can guide the design of appropriate mitigation and compensation scenarios.

For aquatic biota, the assessment focused on whether the various species populations that

comprise the aquatic biological community will be measurably affected. Effects on biota were

evaluated based on an understanding of pathways of likely interaction that can act on individual

organisms with the Project. However the ultimate measure and significance of these interactions

rests at the population level.

TABLE 3.2-1

Evaluation Criteria used in the AE

Sub-Component (AE) Evaluation Criteria or Parameter

Aquatic Habitat Quantity (i.e., area) and quality (i.e., function and relative

productivity with respect to aquatic community).

Aquatic Biota Population conservation (i.e., impingement losses in the

context of known or likely population size of VEC indicator

species).

The works and activities with potential to interact with the AE were evaluated, as described

below, to determine if the interaction was likely to result in a measurable change to the sub-

components of the AE. Those works and activities for which there is an identified surface water

and/or air quality pathway to the AE, but that will be addressed primarily by other technical

disciplines were not directly assessed here. It was expected that any residual effects of those

pathways would be assessed against criteria relevant to those disciplines and, due to a

combination of effects management features and any necessary additional mitigation measures,

would not result in measurable change to aquatic habitat or populations of aquatic organisms.

The potential environmental impacts were assessed considering different categories, levels and

criteria. The definitions and levels for the different categories are presented below:




3-7

Direction: The direction of an impact may be positive, neutral or negative with respect to a

given issue (e.g., enhancement of aquatic habitat would be classed as a positive direction,

whereas habitat loss or fragmentation would be considered a negative direction).

Extent: The spatial area affected by the project. For the purposes of this assessment Extentwas classified as: within the SSA, the LSA or the RSA.

Magnitude: This describes the amount of change in a measurable parameter or the

predicted/actual level of change relative to an existing or specified condition. Magnitude was

defined according to the specific nature of the impact. For the purpose of this assessment,

magnitudes were classified as: negligible, low, moderate and high.

Duration: This refers to the length of time over which an environmental impact occurs. For

the purpose of this assessment, duration was classified as: low (i.e., lasting only during the

Site Preparation and Construction Phase), moderate (i.e., lasting the entire Operation and

Maintenance Phase) and high (i.e., extending beyond the closure of the project, sometimes in

perpetuity).

Reversibility: This is an indicator of the potential for recovery of a given receptor from the

impact. For the purpose of this assessment, reversibility was classified as high for impacts

that reversible immediately after the source of the impact is removed, moderate for impacts

that reverse in the short term, low for impacts that are reversible in the long term only or are

irreversible.

3.2.1 Site Preparation and Construction Phase

3.2.1.1 Mobilization and Preparatory Work and Excavation and Grading

Darlington Creek Road Crossing

The construction of the access road may include a crossing of Darlington Creek at the northeast

corner of the DN site. The crossing is assumed to be a box culvert similar to existing crossings of

the creek at the South Service Road and Highway 401. The construction of the box culvert could

result in local habitat destruction, and would constitute a HADD under section 35(2) of the FA.

As such the Darlington Creek road crossing was advanced for assessment.

Removal of On-Site Ponds

Development of a soil disposal area north of the CN rail line will require removal of Treefrog,

Dragonfly and Polliwog Ponds at the clearing and grubbing stage. The ponds were constructed

in a natural depression as part of OPG’s biodiversity program at the DN site. As the ponds

represent a measurable proportion of on-site aquatic habitat, their loss was advanced for

assessment.




3-8

Removal of Upper Reaches of Intermittent Tributaries to Darlington Creek

Excavation south of the CN rail line will be required to construct the station and ancillary

facilities. Much of the excavated material will be deposited as a large mound north of the CN rail

line. Each of these areas contains about 400 meters of intermittent swale that drains into

Darlington Creek. These features will be lost at the clearing and grubbing stage. In the soil

disposal area, it may be possible to restore similar habitat as part of drainage and stormwater

management and maintain the connection to Darlington Creek. In the area of the NND station,

grades will be altered so much that the drainage from the former swale catchment will be

diverted to Lake Ontario instead of Darlington Creek. It may be possible to create a swale to

offset the loss of the existing feature, but the connection to Darlington Creek will be lost. As a

measurable reduction of “indirect” or “contributing” fish habitat could occur, removal of the

upper reaches of the intermittent tributaries was advanced for assessment.

Areas dependent on groundwater discharge to the east of the site (i.e., Darlington Creek), if

present, will be minimally affected by the dewatering of the site. It is estimated that between

5-7% of the total Creek volume would be reduced as a result of dewatering activities (see

Geological and Hydrogeological Environment Assessment of Environmental Effects TSD).

However, this is not expected to have a significant impact on the Darlington Creek fisheries.

Alteration/Disruption of Coot’s Pond

Project use of the existing construction waste landfill could change the shape and extent of its

footprint. Coot’s Pond will be avoided to the extent possible, but there could be minor alteration

or temporary disruption of portions of the pond. Affected areas of the pond will be restored

following the Site Preparation and Construction Phase. As changes to Coot’s Pond could affect a

measurable portion of on-site aquatic habitat, even temporarily, this effect was advanced for

assessment.

Alteration of Upper Reaches of an Intermittent Lake Ontario Tributary

Project use of the existing construction waste landfill could change the shape and extent of its

footprint, with possible effects on the intermittent watercourse that lies along the east boundary

of the landfill and south of Coot’s Pond. Realignment of portions of the tributary may be

required to allow changes to the extent of the landfill. Marginal upper portions may be filled. As

changes to the watercourse could result in a loss of indirect or contributing fish habitat, this

effect was advanced for assessment.

3.2.1.2 Marine and Shoreline Works - Lake Infill

Preparation of the Project site and expansion of the security perimeter setback from Lake Ontario

in front of DNGS will involve the filling and loss of approximately 40 hectares of nearshore

habitat along approximately 2 kilometers of shoreline, with potential to alter nearshore coastal

processes. Since this activity represents a measurable change in the area of nearshore habitat

within the SSA lake infill was advanced for assessment.




3-9

3.2.1.3 Construction of Intake and Discharge Structures

Construction of the intake and discharge tunnels for the once-through condenser cooling water

system is expected to involve boring or blasting through bedrock beneath the lake bed, with little

scope for interaction with the AE due to the separation of the tunnel from habitat within the lake.

However, blasting and excavation to open the intake tunnel to the lake and to prepare the lake

bed for installation of the porous veneer intake structure could involve incidental fish losses and

will replace an area of the lake bed habitat with an artificial structure. Likewise, blasting and

excavation for the installation of diffuser ports along the discharge tunnel could involve limited

fish losses and will result in the loss of natural lake bed habitat at each port. This interaction

would also occur to some degree with a cooling tower scenario, as intake and outfall structures

would still be required. Although these structures would be smaller (with a smaller permanent

footprint), the method of construction would be open trench and laying of pipe rather than

underground boring beneath the lake and could involve similar total area of temporary

disturbance during construction. As such, the construction of intake and discharge structures

was advanced for assessment.

3.2.1.4 Management of Stormwater

As the site is developed, ditches and swales will be constructed to collect and convey surface

water to stormwater management ponds and ultimately discharge to an existing drainage course

or Lake Ontario. Stormwater management features will be developed to address the

requirements for runoff control both during site preparation and construction (temporary), and

during operations (permanent). There is a potential beneficial effect on fish habitat from

stormwater management facilities once design modifications are implemented.

Good Industry Management Practices during all phases of the NND Project will be

implemented with respect to stormwater management. Examples include: sediment control

practices, dewatering water treatment, stormwater conveyance systems (if necessary), and

conventional stormwater treatment methods such as stormwater management ponds and oil-grit

separators. In addition all water having come into contact with blasting agents (e.g., ANFO)

will be collected and appropriately managed and disposed.

This interaction is not forwarded on for further assessment.

3.2.2 Operation and Maintenance Phase

3.2.2.1 Operation of Condenser Circulating Water, Service Water and Cooling Systems

Impingement and Entrainment

Depending on the cooling-water technology that is selected, intake flows could be as high as

250 m3/s for once-through cooling or 6 m

3/s for cooling towers. For once-through cooling, it is

assumed that a lakebottom porous veneer intake structure will be constructed, likely as a scaled-

up version of the existing intake at DNGS. The DNGS intake design has proven very effective in

mitigating fish losses due its offshore location and designed average approach velocity of

<0.15 m/s (0.5 fps). For the cooling tower option, approach velocity reductions, small intake




3-10

diameter as well as siting the intake away from the nearshore environment will be used as

possible mitigation strategies. Despite the focus on in-design mitigation, lake water withdrawal

under either scenario will result in some impingement of adult and juvenile fish and entrainment

of fish eggs, fish larvae and aquatic invertebrates. A study of DNGS I&E losses was conducted

based on the 2006-7 impingement data collected at DNGS and supported by recent entrainment

studies conducted at DNGS (Ager et al., 2005; Ager et al., 2006). The results have been used in

a case study approach to forecast NND I&E losses that could occur. As such, the impingement

and entrainment effects were advanced for assessment. No SARA/ESA species are expected to

be impinged.

Thermal Discharge

At the other end of the cooling-water system lies the discharge, which will also be subject to

intensive in-design mitigation. DNGS is the model and case study selected for assessment of

thermal effects since its discharge diffuser has proven very effective in mitigating the

development of extensive thermal plumes. Nevertheless, discharge of heated lake water as part

of the operation of a once-through condenser cooling water system will result in measurable

changes to water temperature conditions in the vicinity of the discharge diffuser. This effect was

advanced for AE assessment related to aquatic habitat and biota, and has also been assessed as a

physical effect by the SWE component and presented in the corresponding SWE –

Environmental Effects Assessment TSD. SWE assessed two once-through scenarios, representing

discharge of heated water 9oC and 15.6

oC above Lake Ontario ambient temperature, but

concluded that a mixing zone of similar extent would occur due to the compensating factor of

lower system flow associated with the higher temperature option. As such, the bounding scenario

assessment focuses on the more “conventional” 9oC scenario. Discharge of cooling tower

blowdown would involve a much smaller diffuser structure, flow rate and mixing zone, and is

therefore considered to be bounded by the once-through option.

3.3 Assessment of Likely Effects on the Environment

Preceding assessment steps have identified the various works and activities that may potentially

interact with the AE and, if so, result in a measureable change to its sub-components. This

assessment step evaluates likely environmental effects on VECs and indicator species as a result

of those works and activities. As such, the discussion is organized first by Phase or Project

Work and Activity of the Project, and then by likely environmental effect. The criteria used in

determining if a work or activity was likely to lead to measurable environmental change were

also used for the assessment of likely effects. They are described above in Table 3.2-1.

Professional judgement and the experience of the assessment team remained as important

elements of the applied assessment criteria.

3.3.1 Site Preparation and Construction Phase

3.3.1.1 Darlington Creek Crossing

In-stream construction of box culverts would result in the local loss of a short reach of stream

habitat, as well as potential sedimentation in the creek from construction activities, and would be




3-11

considered as a HADD by DFO (section 35(2) of the FA). A recent habitat assessment of

Darlington Creek indicated that the upper reaches (near proposed in-stream construction) were

the best habitat, and supported rainbow trout (Section 3.3 of the AE Existing Conditions TSD).

Habitat loss could be avoided by mitigation measures that include construction of a two-lane

clear-span bridge, which would avoid in-water works permanent loss of creek habitat. This

design would be consistent with the DFO Operational Statement for clear-span bridges (DFO

2007). Employing appropriate setbacks and sediment and erosion controls during construction,

the crossing would avoid HADD. The crossing would not require section 35(2) FA authorization.

Alternatively, stream crossings could be avoided altogether by aligning the access road further to

the west.

Therefore, in summary, with appropriate mitigation measures applied, there would be no effects

on Darlington Creek aquatic habitat.

3.3.1.2 Removal of Upper Reaches of Intermittent Tributaries to Darlington Creek

Two intermittent swales may be removed as part of NND site excavation and soil disposal

(Figure 3.3.1-1). One tributary is located north of the CN rail line, shown in Figure 3.3.1-1 in

drainage area D2, in the proposed soil disposal area. The other tributary is located south of the

CN rail line, shown in Figure 3.3.1-1 in drainage area E, within the proposed NND station site

footprint. Based on observations by Golder biologists, the portions of the intermittent tributaries

on the DN site do not possess the types of habitat that directly support fish or aquatic

invertebrates. However, flow in the tributaries contributes to aquatic habitats downstream and

they would therefore be considered “indirect” or “contributing” fish habitat by DFO.

The north tributary is an intermittent swale within an agricultural field that occupies the DN site

and also extends eastward to Darlington Creek. Golder’s on-site observations confirmed a lack of

aquatic habitat attributes in the on-site portion, aside from the periodic conveyance of runoff.

Agricultural practices on the site include cultivation through the swale and healthy growth of

corn even within the swale, both of which indicated relatively minor flow in this feature despite

heavy summer rainfall during 2008. Approximately 400 meters of the north swale could be lost

or need to be extensively realigned in conjunction with deposition of excess soils in this area.

However, realignment and incorporation of site drainage features into a SWM design for the soil

disposal stockpile is expected to maintain contributions of flow into the lower reaches of the

northern tributary and to Darlington Creek.

The south tributary is an intermittent swale that originates as ditch drainage within a portion of

the former DNGS construction laydown area and extends southeastward through regenerating

former agricultural lands (often called “old field” habitats), hedgerow and reed canary grass

meadow to the eastern property boundary. Approximately 250 meters downstream of the DN site

property line, it joins the channelized lower portion of Darlington Creek, approximately

200 meters upstream of Lake Ontario. Approximately 400 meters of the uppermost reach of the

intermittent tributary will be lost at the clearing and grubbing stage. The area of the south

tributary will be excavated for the NND station, such that the excavated area will drain towards

Lake Ontario and it is unlikely that realignment or SWM strategies could maintain the




3-12

contribution of flow from the lost portion to the remaining downstream tributary segment and to

Darlington Creek.

The loss/alteration of these reaches is considered to represent an effect on the Darlington Creek

tributary aquatic habitat VEC. However, none of the VEC indicator species chosen for the EA

would be measurably affected. Factors that mitigate the sensitivity of Darlington Creek habitat to

the loss/alteration of these reaches include:

The affected portions of the tributaries are intermittent, and therefore do not provide

sustained flow to downstream habitats. Most contributions would occur during snowmelt

and rainfall events when flow is already high in the main branch of Darlington Creek;

The tributaries join Darlington Creek low in its watershed, where the contributions of

flow are less important to Darlington Creek hydrology and resulting habitat

characteristics. The lower reaches have been highly modified from past actitivies on

adjacent sites, and do not provide critical habitat for fish species that spawn in the creek.

The north tributary appeared to be highly ephemeral, and would have little effect on

Darlington Creek flow and habitat. The south tributary has features that suggest higher

flows than in the north swale, however its contribution is unlikely to be critical to a reach

of Darlington Creek that has been extensively altered (i.e., channelized and realigned)

and is influenced by Lake Ontario water levels and discharge from the St. Marys

operation.

Although they do not directly support fish or other aquatic species, these tributary swales meet

DFO’s definition of “indirect” or “contributing” fish habitat by virtue of their contributions to

water quality, flow, nutrients and food organisms (e.g., terrestrial invertebrates) to the

downstream fishery. DFO is therefore expected to consider the loss of the tributary to represent a

HADD that will require section 35(2) FA authorization and fish habitat compensation as part of a

comprehensive Project fish habitat compensation strategy.

In summary, the on-site construction activities may result in loss of some stream habitat due to

site excavation and soil stockpiling. The tributaries are intermittent and therefore are of low

habitat quality. Since the effects are confined to the SSA, occur only during the construction

phase, and are fully reversible with habitat compensation, the effects due to removal of the upper

reaches of the tributaries to Darlington Creek are considered to be of negligible overall

environmental impact. In addition, Geological and Hydrological Environment Assessment of

Environmental Effects TSD notes that during the Site Preparation Phase, the preparatory works

will move soil and rock from excavations around the site and groundwater flow will charge and

concludes that a higher recharge adjacent to Darlington Creek will add baseflow to Darlington

Creek and compensate for the loss of baseflow in the lower reaches of the creek.

3.3.1.3 Removal of On-Site Ponds

The ponds were constructed in a natural depression as part of OPG’s biodiversity program at the

DN site (Figure 3.3.1-1). The ponds lack strong physical connection to local streams and

tributaries. While there is the possibility of overflow and drainage into the Darlington Creek

watershed, the potential for and frequency of these occurrences seems low based on the low




3-13

water levels typically encountered in the ponds and the lack of defined outflow channels. There

is further, topographical separation of the ponds from downstream portions of the watershed

represented by the excavated right-of-way of the CN rail line. Migration of aquatic species

upstream to the ponds is prevented by this barrier. The constructed ponds do not support fish and

appear not to contribute directly or indirectly to downstream fisheries in any measurable way.

Removal of the ponds is not expected to require a FA authorization or fish habitat compensation,

although OPG may choose to create similar habitat elsewhere to offset the loss on-site habitat

and biodiversity. An obvious opportunity to offset loss of the ponds lies in the design of SWM

facilities for the soil disposal area north of the CN rail line. Shallow wetland habitat could be

established in swales, ditches and detention ponds. Similar aquatic communities exist or are

developing on the site in several SWM facilities including Coot’s Pond and SWM ponds built in

conjunction with recent development around the DN site.

New Nuclear-Darlington Aquatic Environment



3-14




3-15

Common aquatic plant and wildlife species reside in the ponds. Removal of Treefrog, Dragonfly

and Polliwog Ponds does not involve any of the VEC indicator species that were chosen for the

EA. A net reduction of aquatic habitats represented by shallow ponds and wetlands could occur

within the SSA, but may be offset by habitat created in SWM ponds and associated channels.

The habitat potential of SWM ponds at the DN site is demonstrated by Coot’s Pond. However,

even without SWM offsets, loss of the ponds is not expected to affect local or regional

conservation of similar aquatic habitat and associated species.

In summary, removal of the ponds will result in loss of on-site aquatic habitat, and the impact is

considered of high magnitude within the SSA since there are a limited number of aquatic habitats

on-site. The ponds provide relatively uncomplicated aquatic habitat of low sensitivity that could

be re-created elsewhere on the site. The ponds are also small in area and therefore comprise a

small fraction of similar habitat within the local and regional areas. Loss of the ponds will not

measurably affect local or regional conservation of similar aquatic habitat and associated species,

however, their loss is acknowledged as an effect of the Project, particularly in that opportunities

to mitigate the loss are readily available as noted above. Since the effects are confined to the

SSA and are fully reversible with restoration of similar habitats on-site, the effects associated

with removal of the on-site ponds are considered to be of negligible environmental impact after

mitigation.

3.3.1.4 Alteration/Disruption of Coot’s Pond

The extent of possible alteration or disruption of Coot’s Pond (Figure 3.3.1-1) is not defined, as

the final configuration of an expanded construction waste landfill is unknown. Temporary

disturbance may occur, as a bounding scenario, however, it is the intention of the Project that the

ecological attributes that have been successfully encouraged by OPG at the Coot’s Pond location

will be maintained through in-design mitigation measures incorporated for that purpose and the

affected portions of the pond will be restored.

In addition to its primary role as a SWM and settling pond, Coot’s Pond was intended to be

fishless to promote amphibian biodiversity on the DN site. The pond’s connection to the nearby

intermittent tributary is limited to its outflow structure, which provides a barrier to upstream fish

migration, should there be any fish in the adjacent watercourse. Despite this strategy a population

of northern redbelly dace has become established in the pond, likely as the result of release of

bait fish by the public. However, since the pond is a treatment facility and is very poorly

connected to nearby fish habitat, it is unlikely that DFO would consider it to be fish habitat

subject to section 35(2) FA provisions. As such, it is unlikely that effects on Coot’s Pond would

need to be addressed as part of the fish habitat compensation plan for the Project.

In summary, the existing Coot’s Pond was originally constructed as part of the on-site

stormwater management and settling pond system associated with the Northwest Landfill. The

pond now supports an attractive emergent wetland community. However, the pond provides

aquatic habitat of relatively low sensitivity and was not designed to be connected to aquatic

habitat. Further, since the effects will be kept to a minimum, are confined to the SSA and are

fully restorable following Site Preparation and Construction, the overall environmental impact of

the potential alteration/disruption of Coot’s Pond is considered to be negligible.




3-16

3.3.1.5 Alteration of Upper Reaches of Intermittent Lake Ontario Tributary

Changes to the intermittent Lake Ontario tributary (Figure 3.3.1-1) are not defined, as the final

configuration of an expanded construction waste landfill is unknown. The worst case scenario

would entail a realignment of portions of the watercourse eastward, closer to Park Road,

combined with filling of ephemeral ditch and swale features. Although upstream migration of

fish from Lake Ontario is not possible, and the likelihood of pre-existing populations of resident

fish species is low due to the intermittent nature of the watercourse, the tributary possibly hosts

northern redbelly dace as a result of one-way migration downstream through the Coot’s Pond

outfall. Recent beaver activity has created a series of beaver ponds along the tributary that

provide more permanent aquatic habitat suitable for such fish despite the intermittent flow

regime. Changes to the tributary could therefore directly affect fish habitat and would represent a

HADD that will require section 35(2) FA authorization and fish habitat compensation as part of a

comprehensive Project fish habitat compensation strategy.

In summary, the expansion of the waste landfill may result in degradation of stream habitat

through removal and re-alignment of sections of the tributary. Since the stream is intermittent, it

is considered to be of low to moderate habitat quality and comprised of relatively simple aquatic

habitat. The loss of the affected reaches will be offset through the fish habitat compensation plan.

Therefore this is considered to be an impact of negligible magnitude.

3.3.1.6 Lake infill

Lake infill associated with the Project will involve the loss of approximately 40 hectares of

nearshore habitat along approximately 2 kilometers of shoreline (Figure 3.3.1-2), comprised of a

westerly portion of armoured and previously filled shoreline adjacent to DNGS, and an easterly

portion of natural shoreline at the foot of Raby Head. Filling along the portion in front of DNGS

will advance the previously filled and armoured shoreline in a narrow band slightly further and

deeper into Lake Ontario, resulting in some loss of nearshore habitat in approximately the 4 to

5-meter depth range but not altering shoreline conditions appreciably. Lake infill at the NND

site will be more extensive to provide necessary construction laydown area and will replace the

natural shoreline and gradual lakebed contours with an armoured shoreline adjacent to deeper

water out to approximately 5 meters depth.

A 40 hectare lake infill area represents a considerable effect on the Lake Ontario nearshore

habitat VEC on the scale of SSA and LSA, but affects only a very small proportion of the

nearshore habitat that exists within the RSA.

The exposure of the lake infill area shoreline to wind, wave and current action creates a high-

energy aquatic environment. The coarse substrates of gravel and cobbles near the beach are

frequently displaced during storms. As a result, changes in sedimentation patterns due to

alteration of the shoreline can be expected, although effects would be relatively localized. Any

sediment deposition is likely to occur further offshore, in deeper water, as a result of extension of

the shoreline into Lake Ontario.




3-17

There may be effects due to the construction of the infill area such as increased temperatures and

possible algal growth in an embayment between Darlington Creek and the proposed lake infill

area. If monitoring indicates that algae growth in the area is expected be a problem, physical

modifications to the shoreline in the area could be undertaken. These could include minor

changes to the infill design geometry and/or further means such as additional lake infill to

enhance water circulation to flush nutrients that could contribute to algal growth, or alternatively,

measures to reduce water circulation, favouring the creation of a coastal wetland or marsh,

dominated by vascular plants that would compete with algae for nutrients.

Underwater video images were collected at 27 locations in and immediately-adjacent to the

proposed lake infill zone acquired in November 2008 during the EA studies. The images

suggested that substrates in the area could be grouped into six major categories ranging from

finer sediment (sand or silt) over bedrock to densely packed cobble and boulders

(Figure 3.3.1-2). Substrate types can be summarized as follows:

1. Finer sediments over bedrock with patches of exposed bedrock;

2. Finer sediments usually with distinct ridges and/or ripples;

3. Finer sediments with scattered gravel and cobble;

4. Gravel and cobble in a base of finer sediments;

5. Rocks ranging in size from gravel to boulders in a base of finer sediments; and

6. Densely packed cobble and boulders.

The western portion of the proposed infill area is dominated by rocky substrates. In the eastern

portion of the area, rocky substrates tended to (with some exceptions) dominate the locations

closest to shore, transitioning to more sandy substrates in deeper areas. Additionally, dead

mussel shells could be seen throughout the infill area. Shell numbers were highest in the western

portion of the potential infill area, reaching their highest densities at the eastern edge of the

armoured shoreline, becoming almost non-existent in the easternmost area of the site. This area

is not considered optimal fish spawning habitat.




3-18

FIGURE 3.3.1-2

Distribution of Sediment Types Identified by Underwater Video within the Proposed Lake

Infill Area

Recent benthic sampling within the proposed infill area collected in November 2008 is shown in

Figure 3.3.1-3. Low invertebrate densities collected in the proposed lake infill zone were typical

of benthic communities in other high energy littoral zones of Lake Ontario where shifting

substrates, limited interstitial space and little organic accumulation result in the presence of only

relatively few, tolerant invertebrate species and populations.

FIGURE 3.3.1-3

Benthic Invertebrate Sampling Locations within the Proposed Lake Infill Area

Effects on VEC indicator species can be summarized as follows:

Benthic invertebrates – localized mortality and loss of habitat within the lake infill

footprint. However, recent benthic results shown that densities are quite low, and involve

few species. Species and community conservation will not be affected as extensive

Type 1

Type 2

Type 3

Type 4

Type 5

Type 6




3-19

benthic invertebrate habitat exists in the LSA and RSA. Bloody red shrimp, a recent

invasive species, was also reported in the area from 2009 spring surveys (AE Existing

Conditions TSD). However, they are not expected to increase because of the lake infill;

Round goby – localized mortality and loss of habitat within the lake infill footprint.

Although round goby has become an important prey fish species in the Lake Ontario food

web, conservation of this widespread exotic invasive species is not a concern. Recent

(2009) spring surveys have indicated the dominance of this species in nearshore habitats

(AE Existing Conditions TSD);

Emerald shiner – loss of nearshore spawning, nursery and foraging habitat within the lake

infill footprint. Emerald shiner within the fill area will be salvaged prior to lake filling

and released back into the lake. Conservation of this species will not be affected as

similar habitat is extensive within the LSA and RSA;

Alewife – loss of a very small portion of the nearshore spawning and nursery area of the

lakewide alewife population. Alewife within the lake infill area will be salvaged prior to

filling and released back into the lake. Conservation of alewife will not be measurably

affected given the extent of remaining suitable habitat and the size of the alewife

population;

White sucker – loss of nearshore foraging habitat within the lake infill footprint.

However, potential benthic forage species exist at low densities and species diversity.

Spawning and nursery habitats will not be affected as they are located in tributary creeks

and rivers. White sucker within the lake infill area will be salvaged prior to filling and

released back into the lake. Conservation of the white sucker population will not be

affected as extensive nearshore habitat exists in the area and white sucker are common

and widespread;

Round whitefish – loss of a portion of potential spawning and nursery habitat, as well as

seasonal foraging habitat within the lake infill footprint. Historical distribution suggests a

wide distribution from Pickering to Port Hope (Haymes and Kolensoky 1984). However,

few larval round whitefish were observed in the vicinity of DNGS (in decline), and only

one was observed in the proposed lake infill area during the 2009 spring sampling

program (Section 3.8 of the AE Existing Conditions TSD). Most construction will likely

take place during the summer, when warm water temperature would exclude whitefish

and other coldwater fishes from the lake infill area. However, construction of the

perimeter berm is likely to extend beyond the summer months. Therefore, adult round

whitefish within the lake infill area will be salvaged and released to Lake Ontario prior to

filling within the contained area. Still, few adult fish are expected based on the population

decline of the species lakewide (Hoyle Pers. Comm. 2009). Conservation of the round

whitefish population will not be affected, as extensive similar habitat exists in the area;

Lake sturgeon – loss of a portion of foraging habitat. Sturgeon within the lake infill area

will be salvaged and released to Lake Ontario prior to filling. As the lake infill area does




3-20

not contain critical sturgeon habitat, but represents a small portion of widespread

nearshore foraging areas, the lake infill area is not expected to affect lake sturgeon

population conservation;

American eel – loss of a portion of foraging habitat. Eels within the lake infill area will

be salvaged and released to Lake Ontario prior to filling. As the lake infill area does not

contain critical eel habitat, but is a small part of extensive nearshore feeding grounds, eel

population conservation is not expected to be affected;

Lake trout - loss of a portion of potential spawning and nursery habitat, as well as

seasonal foraging habitat within the fill footprint. Most construction will likely take place

during the summer, when warm water temperature would exclude lake trout and other

coldwater fishes from the lake infill area. However, construction of the perimeter berm is

likely to extend beyond the summer months. Therefore, lake trout within the lake infill

area will be salvaged and released to Lake Ontario prior to filling, within the contained

area. Conservation of the lake trout population will not be affected, as extensive similar

habitat exists in the area and stocking continues for this species to offset lakewide poor

natural reproductive success; and,

Salmonid sport fish – loss of a portion of seasonal foraging habitat within the lake infill

footprint. Spawning and nursery areas for trout and salmon species that make up the sport

fishery occur in tributary creeks and rivers and will not be affected by lake infill. Access

to Darlington Creek will not be altered, and changes in shoreline processes are not

expected to result in alteration of sediment deposition patterns that would prevent access

to the creek. Most construction will likely take place during the summer, when warm

water temperature would exclude coldwater fishes from the lake infill area. However,

construction of the perimeter berm is likely to extend beyond the summer months.

Therefore, trout and salmon within the fill area will be salvaged and released to Lake

Ontario prior to filling within the contained area. Risks to conservation of these species is

not of concern as their populations are maintained by stocking and natural reproduction

in tributaries beyond the influence of the lake infill.

Measurable direct mortality is therefore only likely to be associated with benthic invertebrates

and the benthic round goby VEC indicator species, which cannot be feasibly salvaged from the

fill area. However, there is no conservation concern associated with mortality of these

widespread species in such a limited area.

Although population conservation and production on a regional or lakewide scale is unlikely to

be measurably affected by the lake infill, it remains that a measurable area of habitat will be lost

that is currently productive to varying degrees for all of the VEC indicator species. Studies

confirm that the affected area is similar to extensive areas of the Lake Ontario north shore and

indicate that it is a high energy zone, with a benthic community of low density and diversity, and

little likelihood of containing critical areas of fish habitat. Still, this is the nature of fish habitat

within this portion of the nearshore and a section 35(2) FA authorization will be required, along

with fish habitat compensation measures to offset the loss of habitat and associated productivity.




3-21

In summary, the construction of the lake infill will result in the loss of nearshore habitat, as well

as construction-related impacts, such as increased turbidity during construction of the cofferdam

and along the fill face. Since site management practices will be implemented to reduce erosion

and sedimentation, and resulting turbidity in the nearshore is expected to be similar to that which

occurs during storm events, increased turbidity is considered to be an impact of low magnitude.

Since the lake infill does not affect a meaningful proportion of habitat for any of the VEC

indicator species, there are extensive areas of similar habitat all along the north shore of Lake

Ontario, and compensation for habitat loss will be undertaken, the effects of the lake infill

structure on the aquatic habitat of Lake Ontario are considered to be of negligble overall

environmental impact.

3.3.1.7 Construction of Intake and Discharge Structures

Construction of the intake and discharge for the once-through condenser cooling water system

will interact with the AE due to blasting and excavation to connect the intake tunnel to the lake,

to prepare the lake bed for installation of the porous veneer intake structure and to install the

diffuser ports along the discharge tunnel. Blasting could involve incidental fish losses. The

porous veneer intake structure and the diffuser ports and will occupy approximately 1.1 hectares

and 0.7 hectares of the lake bed, respectively.

The intake structure will be situated in approximately 10 meters depth, in the zone that was

determined in studies conducted for the placement of the DNGS intake to be offshore of the

highest concentrations of fish and inshore of the highest concentrations of Mysis (freshwater

shrimp). The discharge diffuser will be situated along an alignment of approximately

1100 meters, similar to DNGS, but in deeper water than DNGS, ranging from approximately 10

to 20 meters.

Siting of the intake and discharge diffuser structures will minimize the interaction with the VEC

indicator species by avoiding shallow warmer water and nearshore spawning areas. Interactions

can be summarized as follows:

Benthic invertebrates – localized mortality and permanent loss of habitat within the

affected areas. Species and community conservation will not be affected as total area

affected is small;

Round goby – localized mortality and permanent loss of habitat within the affected areas.

Conservation of this widespread exotic invasive species as a forage species is not a

concern, especially since the total area affected is small;

Emerald shiner – little interaction is expected as the works avoid the primary nearshore

habitat of emerald shiner;

Alewife – localized incidental mortality of small numbers of alewife due to blasting. Area

of habitat affected is negligible against total available alewife habitat;

White sucker – little interaction is expected as the works avoid the primary nearshore

habitat of white sucker;

Round whitefish – little interaction is expected as the works avoid the primary nearshore

spawning areas of round whitefish. Incidental mortality of a few individuals could occur




3-22

with blasting. Recent larval fish studies (spring 2009) have indicated the low relative

abundance and distribution of round whitefish in the vicinity of DNGS (AE Existing

Conditions TSD);

Lake sturgeon – little interaction is expected as the works avoid the shallow areas of the

nearshore;

American eel – little interaction is expected as the works avoid the shallow nearshore

areas;

Lake trout – little interaction is expected as the works avoid the primary nearshore

spawning areas of lake trout and total area of habitat affected is negligible against

available habitat. Incidental mortality of a few individuals could occur with blasting; and,

Salmonid sport fish – incidental mortality of a few individuals could occur with blasting.

Area of habitat affected is negligible against total habitat availability for these species.

In summary, incidental mortality of limited numbers of individuals of a few VEC indicator

species could occur due to blasting. Underwater blasting will be subject to DFO review and

likely will require section 32 authorization under the FA, for destruction of fish by means other

than fishing, which will involve development of mitigation strategies to minimize harmful

effects on fish. Since the project results in a HADD of fish habitat, the conditions associated with

a section 32 authorization under the FA will be included within the section 35(2) authorization.

Mortality of relatively small numbers of fish during the Site Preparation and Construction Phase

is not considered likely to be of conservation concern relative to the population of any of the

VEC indicator species.

A small area of habitat will be lost to the intake and discharge structures. As these areas will be

located offshore in deeper water, the loss of this habitat is not considered likely to affect any of

the VEC indicator species in a meaningful way. Nevertheless, a section 35(2) FA authorization

will be required for this and other Project works and activities, and a comprehensive fish habitat

compensation plan will offset the loss of habitat and associated productivity.

In summary, the construction of intake and discharge structures into Lake Ontario for the cooling

tower option would involve excavation of a trench and laying of pipe that could result in

temporary disturbance of habitat. Once construction is complete, habitat loss will be restricted to

the small areas of the intake and discharge structures. Blasting during construction could result in

lethality in some fish species and will be addressed through standard mitigation measures as per

DFO guidance. Sedimentation from construction activities is expected to be localized and

relatively short term and is not expected to result in mortality of benthic organsisms or

permanent alteration of nearby lake substrates.

Construction of the intake and discharge structures for the once-through cooling option would

involve tunneling beneath the lake. Therefore, lakebed disturbance is limited to the porous

veneer intake and individual diffuser ports, which would be permanent structures on the lake

bottom. The habitat loss would be restricted to the footprints of these structures, and this is

considered the bounding condition for disturbance of lake bottom habitats. Since small areas of

lake bottom will be affected, extensive areas of similar habitat are available nearby, any habitat




3-23

loss will be offset through the fish compensation plan, and blasting effects will be mitigated, the

overall effect is considered to be negligile.

3.3.2 Operation and Maintenance Phase

3.3.2.1 Impingement and Entrainment

I&E losses have been addressed by in-design mitigation measures that include a lakebottom

porous veneer intake structure that reduces intake velocity at the interface with the lake and

placement of the structure in approximately 10 meters depth where fish and invertebrate

abundance has been shown to be low. This design is similar to the DNGS intake structure, which

has performed well in reducing I&E losses far below those that occur at other stations on the

Great Lakes. The DNGS impingement and entrainment performance was taken as a case study

for the purpose of assessment of this effect of the Project.

A separate analysis of intake losses has been undertaken concurrently with the EA, using DNGS

entrainment results from monitoring conducted in 2004 and 2006 and impingement data

collected in 2006-2007. The analysis employed modeling techniques similar to those in use in

the United States to address United States Environmental Protection Agency (USEPA)

Regulation 316(b) requirements related to fish losses. Total impingement and entrainment losses

were estimated and the losses were modeled in terms that permit comparison among years and

locations (i.e., other stations) and assessment against conservation criteria.

Overall, it is anticipated that relatively small numbers of fish and aquatic invertebrates will

comprise intake losses associated with impingement and entrainment at the NND station due to

the effectiveness of the intake design and placement. These losses are not expected to result in

measurable changes to population size, production or status of the VEC indicator species. For

small numbers of individuals removed from their respective populations, compensatory

mechanisms of recruitment, growth and survival in the remaining population are expected to

offset the losses.

3.3.2.2 Impingement

The DNGS intake design and location has been very successful in reducing impingement.

Underwater video studies showed that by maintaining low intake velocities, even small fish

could swim over it without being drawn in (Patrick and Poulton 1993). Impingement rates have

been very low compared with other generating stations on the Great Lakes, based on monitoring

undertaken by DNGS operations staff which were used as an index of effectiveness of the intake

design as a mitigation strategy. The DNGS porous veneer intake incorporates features that have

been designed to reduced water velocities at the intake as well as other fish diversion principles.

DNGS CCW intake performance is summarized in Wismer (1997a) and includes impingement

monitoring at DNGS from 1993 to 1996. These data were subsequently highlighted in the

Darlington Ecological Effects Review (DEER) (ESG 2001) to assess impingement losses

(Table 3.3.2-1). Impingement for each year ranged from 164 kg in 1996 to 555 kg in 1994. Still,

these estimates are not annualized and may be under-estimates due to errors in counting and fish

identification (Wismer 1997b). In addition, in 1994, an estimated 1,300 kg of fish, identified as




3-24

alewife, were observed to have bypassed the screens as they were drawn from the forebay, and

were deposited in a screenhouse sump.

Approximately 97% of the fish impinged during the 1993-1996 studies belonged to five

categories, which were alewife, shiner (likely emerald and spottail shiner), rainbow smelt, sucker

(probably mostly white sucker) and whitefish (both round and lake whitefish). All other species

individually comprised only fractions of a percent of total impingement. DNGS impingement

rates have been considered too low to measurably affect the lake-wide populations of any of the

impinged species. Shiner impingement records need to be interpreted with caution as some

misidentification of smelt and alewife as shiners was known to occur, which would overestimate

shiner losses.

TABLE 3.3.2-1

DNGS Impingement Loss Estimates (1993-1996, 2006-2007)***

Year Biomass (Kg) Species Impinged

1993

1994

1995

1996

232

555*

368

164

Alewife, Shiners, Smelt, Sucker, Walleye,

Whitefish, Carp, Salmon, Lake Trout, Rainbow

Trout, Gizzard Shad, Brown Trout, Bass, Eel,

Yellow perch, Catfish, Sunfish, Others (not

speciated)

Dec 2006- Dec 2007 437- 893** Alewife, Longnose Sucker, Pink Salmon,

Rainbow Smelt, Round Goby, Spoonhead

Sculpin, Threespine Stickleback, White Sucker

* Does not include 1300 kg of alewife/debris in sump in June 1994.

** Upper biomass range (893 kg) is based on Unit 4 results (assumes other Units impinge similar

amounts as Unit 4 which is a conservative estimate). 2006-2007 data corrected for station flow.

***The current monitoring frequency for impingement is every three years. The next planned

impingement data collection at DNGS is anticipated in 2010.

Recent impingement sampling at DNGS was conducted over approximately a one-year period by

a qualified biologist from December 13, 2006 to January 9, 2008 (2006-2007 adjusted for station

flow) (SENES 2009). Sampling was typically weekly during the May to August period, and

biweekly from September to April. Although sampling methodology was not as robust as recent

USEPA 316b studies, it does still provide a recent estimate of species impinged and their relative

contributions to impingement for EA purposes. Biomass estimates for the recently collected data

are given in Table 3.3.2-1. Annual impingement was estimated to be approximately 14,119 fish

(437.5 kg). This biomass estimate is within the range from most years reported in the DEER

report (1993, 1995, 1996, but not compared to 1994 results which had significantly higher




3-25

impingement when including fish which bypassed the screens). Still, the 2006-2007

impingement results may still be underestimated due to issues not sampling some Units during

critical impingement periods. However, Unit 4, which is the last Unit in the forebay, had the

highest impingement during the 2006-7 sampling (6,505 fish) as well as the least missed

sampling dates during critical impingement periods. Typically, Unit 4 impinges more fish as fish

become weakened, and move to the end of the forebay. If we assume the other Units impinge as

many fish as Unit 4, then, an estimated impingement would involve 26,020 fish/yr (i.e. 6,505

fish multiplied by 4 operating units) which is likely a conservative estimate. Similarly, station

biomass estimates were extrapolated based on Unit 4 data (which also had the highest values)

and were estimated to be approximately 893 kg (Table 3.3.2-1). An estimated range of

impingement at DNGS could possibly vary from approximately 14,119 (437 kg) to 26,020

(839 kg) fish/yr. In recent sampling, a total of only 8 species were collected of which alewife

and round goby contributed approximately 85.9 and 8.5 % of the total, respectively. Round goby

is a VEC indicator species (Table 3.3.2-1) which was not reported earlier in the DEER Report

(ESG 2001, 1993-1996 data sets). Although goby is a demersal species and impinged, densities

tend to be higher in the nearshore environment in the spring and summer, including at the 10-m

depth where the intake is proposed to be located (AE Existing Conditions TSD). Therefore,

goby impingement is expected to increase. Fall migration occurs to greater depths (beyond

30 m). During this migration period, goby will also come in contact with the intake structure.

However, they have excellent swimming speed capabilities (sustained speeds for short periods

up to 85 cm/s, Pennuto 2009), and should have the ability to avoid the low intake velocities of

the intake structure (average velocity of 15 cm/s). Therefore, although goby impingement is

expected to increase, it is not expected to be significant.

Recent impingement losses of the relevant VEC indicator species based on recent impingement

results can be summarized as follows:

Alewife – The estimated number of alewife impinged annually over the December 2006-

December 2007 period ranged from approximately 12,139 to 23,416 (extrapolated) fish.

These numbers are negligible relative to fish populations in Lake Ontario (Owen et al.

2003). For example, over 236,000 adult alewife were removed from Lake Ontario in

2003 (US side only) for scientific purposes alone. Furthermore, it has been estimated that

approximately 1.03 billion yearling and adult alewife occur in Lake Ontario (LOMU

2007). Still, alewife populations are on the decline and are estimated to be at levels

reported in the early 1990’s (LOC 2009).

White sucker – The estimated number of white sucker impinged annually was 100 and

10 longnose sucker in 2006-7. This is considered very low as white sucker was one of the

most numerous and frequently encountered in gillnet catches at DNGS in field studies.

To put the loss of one hundred white sucker into perspective, experimental gillnetting at

DNGS typically results in the capture (and potential mortality) of more fish on an annual

basis (assuming a seasonal sampling program).

Round Goby- The estimated number of round goby impinged annually was 1,207 fish.

This species was not impinged in earlier assessments (1993-1996, ESG 2001) but is a

recent invasive species. The species is now very well established in the nearshore

environment of Lake Ontario and other Great Lakes, and no serious impact from

impingement on this species is expected. However, an increase in impingement will




3-26

likely be expected because of its benthic nature and high relative abundance nearshore

(AE Existing Conditions TSD). Goby populations tend to be more concentrated nearshore

in the spring and summer (see Section 3.10 of the AE Existing Conditions TSD).

Since other VEC indicator species were not impinged in the recent sampling program, they are

not discussed. In earlier impingement sampling (1993-1996), round whitefish, Americal eel,

lake trout and salmonid sportsfish were impinged; however, numbers were very low (ESG 2001).

A comparison of recent entrainment and impingement at DNGS to other power plants on the

Great Lakes is given in Table 3.3.2-2. These estimates are for general comparison only since

sampling methodologies vary as well as the number of sampling events. Still, these results

provide evidence that DNGS impinges and/or entrains fewer fish relative to other locations on

the Great Lakes which is consistent with earlier data reported by Wismer (1997a).

Although the sample size is limited (n=5), the results do suggest that there is considerable

variability in the number of organisms either entrained or impinged. Variation depends on intake

location (Great Lake), intake type (submerged or surface), and intake flow rate. It is noteworthy

that the number of species either entrained or impinged at DNGS is considerably lower than all

other plants. In addition to numbers impinged, there are also reductions in the number of species

impinged and entrained at DNGS compared to other locations. It should also be noted that some

of these plants also have fish protection devices. For example, the DC Cook (Lake Michigan)

and J.A. FitzPatrick (Lake Ontario) plants have acoustic devices installed to reduce impingement

(Dunning et al. 1992), although acoustic devices at the FitzPatrick plant operate intermittently.

The Campbell plant on Lake Michigan has a USEPA approved wedge-wire screen system which

virtually eliminated impingement, but still entrains some fish eggs and larvae.




3-27

TABLE 3.3.2-2

Comparison of Entrainment and Impingement Estimated Losses at Different Plants on the Great Lakes

Annual Impingement Annual Entrainment

Plant LocationMWe

(gross) Flow m3/s Intake Type No. of

Species

Dominant Species

Impingement No. Impinged

No. of

Species

Dominant

Species

Entrained

(Larvae)

No. of Eggs/

Larvae Entrained

16,833,776 (2004) DNGS

Lake

Ontario3740 150

Submerged

(porous

veneer)

8Alewife

Round goby

14,119-26,020

(2006-7)3

Alewife

common carp 7,601,306 (2006)

D.C. Cook1 Lake

Michigan 2,191 106-145

Submerged

(acoustic

system)

50

Yellow perch

Alewife spottail

shiner

1,386,023 (2005-6) 11 Alewife round

goby cyprinids

105,700,000

(2005-6)

Units 1-2

(13.1)Surface 50

Alewife

Gizzard shad 491,717 (2005-6) 15

Alewife

Spottail shiner

Goby

28,129,042

(2005-6)

J. H. Campbell2 Lake

Michigan 1,200

Unit 3

(17.5)

Submerged

(wedge-wire

screen 3/8”

opening)

N.A.

(screen

size too

small to

capture

fish)

N.A. N.A. 15

Alewife

Spottail shiner

Goby

6,535,452 (2005-6)

Bay Shore3Lake Erie

(Maumee

Bay)

631 35.5 Surface 55

Emerald shiner

Gizzard shad

White perch

46,030,066 (2005-

6)26

Freshwater

drum

Rainbow smelt

Morone spp.

>2,200,000,000

(2005-6)

J.A. FitzPatrick4 Lake

Ontario886 26.1

Submerged

(acoustic

system,

operates

intermittently)

54

Stickleback

(201,563)

Alewife (16,796)

230,534 (2004) NA NA NA

Notes:

1. Data obtained from Normandeau 2007 (Report R-20452)

2. Data obtained from GLEC 2007 (Report 1765-00)

3. Data obtained from Ager et al., 2007 (Report 11206-005-RA-0001-R00)

4. Data obtained from 2004 SPDES Biological Monitoring Report James A. FitzPatrick Nuclear Power Plant (Permit No. NY 0020109, Section 10, CP-04.03).

May 2005.




3-28

The remaining VEC indicator species differ in their susceptibility to impingement. Benthic

invertebrates, when affected by plant operations, are entrained rather than impinged, so this VEC

indicator is not included. Impingement of lake sturgeon is not expected because it is not reported

as a species impinged at DNGS. Impingement of this species is relatively unlikely given the size

of individuals encountered near DNGS in relation to the intake spacing (14 cm), and their ability

to overcome the low velocity of the intake.

Habitat VECs are not affected by intake losses. The effect on fish habitat associated with the

construction and continued presence of the intake structure was addressed as a habitat loss and

offset by fish habitat compensation as a Site Preparation and Construction phase effect.

The NND intake design for once-through cooling will be similar to the DNGS intake and is

expected to be similarly effective in reducing intake velocity and fish impingement. However,

the NND once-through cooling flow has been estimated at 250 m3/s compared to the existing

flow rate at DNGS of 150 m3/s (SWE Effects TSD). To estimate fish losses at the predicted

intake volume of 250 m3/s, a simple linear adjustment was applied to the losses at DNGS.

As stated above, the estimated range of fish impinged at DNGS was from 14,119 to 26,020

fish/yr (approximately 437 to 893 kg) based on the December 2006- December 2007 data.

Assuming impingement between the existing DNGS and the proposed NND (based on the

bounding scenario, once-through cooling option) is based on flow rates alone and have similar

intake velocities, an estimated impingement for the NND would be expected to range from

approximately 23,579 to 43,463/year fish (approximately 731 to 1347 kg, see Table 3.3.2-3

below), which assumes a linear extrapolation between flow volume and impingement, and is

based on professional judgement. Nevertheless, even if this number was doubled, the number

impinged would be low in relation to what has been reported as other at other power plant

facilities on the Great Lakes for impingement (Table 3.3.2-2) and lake-wide populations. In

addition, no SARA/ESA species are expected to be impinged. If impingement occurs, for

example with American eel, an adaptive management plan will be used to consider other

mitigation measures.

TABLE 3.3.2-3

Estimated Total Annual Impingement Losses

DNGS NND

Flow (m3/s) 150 250

Mean Intake Velocity (cm/s) <15 <15

Impingement (estimated) 14,119 – 26,020 fish

(437 to 893 kg)

23,579- 43,463 fish ± 100%*

(731 to 1347 kg)

* Confidence limits (100%) have been assigned since estimates are likely quite variable

Impingement predictions for the NND cooling tower option were based on comparisons with

other intakes on the Great Lakes. Assuming a small diameter pipe for the cooling tower intake

option, an estimate of impingement can be obtained based on operating experience at other

facilities, such as the J.A. FitzPatrick Plant on Lake Ontario, which has a submerged intake, a

relatively small intake diameter (3.3 m) pipe, and a fish protection system (only intermittently




3-29

operated). An estimate of alewife impingement was calculated taking into account the different

flow rates (26.1 m3/s compared to 6 m

3/s for the cooling tower option). Alewife is used for

comparison since it is the dominant species impinged at DNGS and other power plants on Lake

Ontario. A predicted estimate of alewife impingement for the cooling tower option, based on the

impingement at the FitzPatrick Plant, is 3,906 fish/year (121 kg, Table 3.3.2-4). This analysis

assumes a linear relationship between impingement and flow rates at these Plants, and similar

intake pipe diameters which is unlikely since the pipe for the NND cooling tower option would

be smaller in size and would have a much lower flow rate. It also does not take into account

reductions due to the fish acoustic system in place which operated intermittently. Consequently,

based on professional judgement, this estimate is likely +/- 100%.

As an intake diameter pipe is reduced in size, a fish avoidance response would also occur due to

space perception cues. For example, Patrick and Rkman-Filopovic (2004) have shown that

schooling pelagic species such as alewife tend to avoid smaller sized openings based on space

perception cues, compared to other more demersal species such as round goby. These

experiments involved determining fish passage and encounters to different sized pipes (0.34 to

1.0 m) and configurations (angled, straight etc).

TABLE 3.3.2-4

Estimated Alewife Impingement for the Cooling Tower Option

PlantFlow Volume

(m3/s)

Intake

Diameter

(m)

Impingement

No. Annually Fish Species

J.A. FitzPatrick *

(Lake Ontario) 26.1 3.3 16,796 Alewife

NND Cooling

Tower6 Unknown

3,906+/-

100%**

(121 kg)

Alewife

* Data obtained from 2004 SPDES Biological Monitoring Report James A. FitzPatrick Nuclear Power Plant

(Permit No. NY 0020109, Section 10, CP-04.03). May 2005.

** Estimates are likely quite variable so a high confidence level has been assigned (100%) based on Best

Professional Judgement.

Alewife impingement for the NND cooling tower option is estimated to be 3,906/year +-100%

individuals. As such, it is concluded that less than 10,000 fish would be expected to be

impinged, on an annual basis with the cooling tower option with the majority of fish being

alewife. Smaller pipe systems (1.0-1.2 m) currently in place in Lake Ontario for water treatment

and other water usages impinge very few fish. Impingement for the NND cooling tower will be

dependent on location, pipe diameter, flow rate and flow velocity. Design requirements for the

cooling tower intake must take into account fish behavioural principles in order to reduce

impingement. Therefore, the cooling tower option will include fish deterrents and/or other

mitigation to further reduce impingement and entrainment losses.

In summary, the operation of the once-through cooling system (bounding scenario) or the

cooling tower option will result in impingement of negligible numbers of VEC fish indicator




3-30

species relative to their populations in Lake Ontario. Since the effects are confined to a small,

relatively unproductive area of the SSA around the offshore intake, and are minimized by the

design that reduces water velocity at the intake and is based on fish diversion principles, the

effects on VEC indicator species populations in Lake Ontario due to impingment of fish are

considered to be of very low overall environmental impact. No SARA/ESA species are expected

to be impinged or entrained.

OPG accepts the obligation under the FA to provide acceptable and adequate

mitigation/compensation measures for the potential impacts to fish and fish habitat relating to the

NND Project. The final mitigation/compensation plan will fulfill the requirements for an

authorization under section 35(2) of the Act (HADD). The final plan will also contain

components that will address the requirements under section 32 of the FA (for the destruction of

fish by any means other than fishing).

3.3.2.3 Entrainment

To mitigate entrainment of fish and aquatic invertebrates, the DNGS intake was installed at a

10 m depth of water. This area of the nearshore near DNGS had been determined to be offshore

of the highest concentrations and diversity of fish eggs and fish larvae, and inshore of the highest

concentrations of Mysis, a shrimp-like aquatic invertebrate (Maher 1980). Entrainment is

extremely unlikely for the early life stages of fish that spawn in tributary streams or nest in

protected warmwater habitats of coastal marshes. Entrainment is therefore only likely for those

species that spawn in the nearshore.

The DEER (ESG 2001) summarized entrainment effects as involving mainly alewife, rainbow

smelt and slimy sculpin. Although estimated numbers of larvae lost to entrainment were high

during the 1993 and 1995 studies cited in ESG 2001, the numbers of equivalent adults were

considered negligible to lakewide populations of alewife and smelt at that time. The population

context was not as firm for assessment of the importance of approximately 8,000 equivalent

adult slimy sculpin, which was noted to have suffered a lake-wide decline, likely as a result of

food web changes. Entrainment studies conducted at DNGS in 2004 (Ager et al., 2005) and

2006 (Ager et al., 2006) failed to detect slimy sculpin. Very few eggs or larvae were detected.

The species observed in the samples were limited to alewife, smelt, freshwater drum and

common carp. Losses were estimated in terms of total numbers of larvae and also adult

equivalents. In 2004, it was estimated that 15,631,833 eggs and 1,201,943 larvae were entrained.

Entrained organisms represented 1,318 age-1 equivalent smelt and alewife. Production foregone,

the biomass which would have been produced if fish were not entrained, was estimated to be

only 46.2 kg. These estimates may be underestimated since sampling period was limited to the

June 14 to August 31 period (Ager et al., 2005). More intensive sampling occurred in 2006

which ocurred over the March 23 to September 23 period (Ager et al., 2006). In 2006, it was

estimated that 605,059 eggs and 6,996,246 larvae were entrained annually. Entrained organisms

represented 11,548 age-1 equivalent alewife, common carp and freshwater drum. These

relatively small estimated losses were not considered meaningful to populations of these species.

They are also low relative to other power plants on the Great Lakes (Table 3.3.2-2).

Invertebrate entrainment was also addressed in ESG 2001 and in Ager et al., 2006. Although

estimates of chironomid, amphipod and Mysis losses involved large numbers, the respective




3-31

studies cited high nearshore densities and huge lake populations of these organisms and

concluded that they are unlikely to be affected.

Entrainment losses relevant to the VEC indicator species can be summarized as follows:

Benthic invertebrates – not entrained in numbers sufficient to affect large populations;

Emerald shiner – not detected in recent sampling. Spawning and nursery areas inshore of

intake;

Alewife – egg/larvae losses equivalent to thousands of adult females (negligible to

lakewide population of 1.03 billion, LOMU 2007); although still high, alewife population

have declined to levels reported in the early nineties (LOC 2009).

Round goby – not detected in recent sampling. Benthic habits may limit susceptibility to

entrainment;

White sucker – not detected in recent sampling. Spawning and nursery areas are in

tributaries, well removed from intake;

Round whitefish – not detected in recent sampling. Spawning and nursery areas are in the

Lake Ontario nearshore, resulting in continued susceptibility to entrainment. However,

lakewide populations are on the decline (Hoyle, 2009), and few round whitefish larvae

have been reported in the vicinity of DNGS during spring 2009 studies (see Section 3.8

of the AE Existing Conditions TSD).

Lake sturgeon – not detected in samples. Spawning and nursery areas for small juveniles

likely do not include the nearshore adjacent to the DN site;

American eel – egg/larval life stages are marine. Entrainment is not possible;

Lake trout – not detected in sampling. Successful reproduction of this species offshore of

the DN site remains unconfirmed and is doubtful given low incidence of reproduction of

this population in Lake Ontario. Entrainment could occur in future if lake trout natural

recruitment picks up; and,

Salmonid sportfish – not detected in sampling as the trout and salmon species spawn and

pass their early life history in tributary streams (or hatcheries). There is no entrainment

pathway for these species.

Entrainment at NND is expected to similarly be dominated by alewife and smelt, the two most

numerous fish species that spawn and occur as larvae in the nearshore. Although the 250 m3/s

once-through flow is expected to entrain more fish than DNGS, the losses are expected to remain

on the level of thousands of adult alewife equivalents against lake-wide populations numbering

estimated at 1.03 billion (LOMU 2007). Although these alewife estimates are still very high,




3-32

lakewide populations of alewife have declined to levels reported in the early nineties (LOC

2009). Still, there is also the need to increase the forage base in Lake Ontario for some species

but not alewife (since they are not considered an optimal prey species for predators such as lake

trout and introduced atlantic salmon). Partly for this reason, LOMU and state agencies are

investigating stocking programs involving ciscoes and lake herring (not alewife) to increase the

forage base (Honeyfield Pers. Comm. 2009).

Entrainment of other fish species is expected to be low, related only to the incidental capture of

some species and a lack of an entrainment pathway for those species that do not spawn or pass

early life stages in proximity to the intake. Invertebrate entrainment is expected to be limited to

the extremely abundant chironomids and amphipods, the populations of which are unlikely to be

affected. Assuming that its intake location would be chosen to minimize contact with aquatic

organisms, similar to once-through cooling, the entrainment losses related to a cooling tower

option at the NND are expected to be very low since the 6 m3/s intake of makeup cooling water

and service water is considerably less than the DNGS and NND flow rates.

In summary, the operation of the once-through cooling system (bounding scenario) will result in

the entrainment of invertebrates as well as the eggs and larvae of some fish. The effects will be

confined to a small area of the SSA around the intake that is located in an area of low larval fish

and invertebrate density. The effects are further mitigated by design features that include

reducing water volocity at the intake. Historical and recent entrainment monitoring has failed to

detect entrainment losses that would affect populations. The existing DNGS intake structure has

been designed to mitigate entrainment and impingment mortality and the NND intake structure

will be at least as effective in minimizing the impingement and entrainment. The estimated

numbers entrained and impinged at NND (based on DNGS data) are considerably lower than

other power plants on the Great Lakes, and would be negligible relative to lake-wide

populations.





components that will address the requirements under section 32 of the Fisheries Act (for the

destruction of fish by any means other than fishing).

3.3.2.4 Thermal Discharge: Once-Through Cooling System

An offshore discharge diffuser was installed at the DNGS to enhance mixing of the thermal

effluent with lake water and limit the development of a thermal plume. Performance of the

DNGS diffuser has met expectations (Romanchuk and Burchat, 1997; Kissel, 1997) by

preventing the dispersion of heated water more than 2oC above ambient beyond a mixing zone

along the diffuser alignment. The design of the diffuser is such that mixing and dilution occurs

rapidly and there is minimal contact of heated water with lake bed substrates and no propagation

of an extensive thermal plume as occurs with stations that employ surface discharge channels.

These studies found that under cold weather conditions, the thermal plume mixed vertically with

the water column before dispersing as a “diving plume” of more dense 4oC mixed water beneath




3-33

colder ambient lake water. This slight elevation of lakebottom temperature, within the range of

naturally occurring winter water temperatures, was considered unlikely to harm round whitefish

eggs or larvae. Diving plumes were also found to occur during the summer in conjunction with

upwellings of colder water from the hypolimnion of Lake Ontario that cause wide natural

fluctuations of nearshore water temperature. Occurrence of these plumes during the summer does

not coincide with the spawning or incubation period of any fish species known to spawn in this

area of the Lake. Otherwise, under warm water conditions, the plume was found to mix vertically

with the water column within the mixing zone, the warmer mixed water forming a buoyant

plume in the vicinity of the diffuser.

The use of a discharge diffuser was also assessed as a physical effect by the SWE component

and presented in the corresponding SWE – Assessment of Environmental Effects TSD. The SWE

assumed that once-through cooling at NND would raise the temperature of discharged water 9oC

above Lake Ontario ambient water temperature. This scenario would employ a diffuser of similar

pattern but scaled up in terms of port diameter to allow 250 m3/s flow. Operation of this diffuser,

which would extend into deeper water than the DNGS discharge due to bathymetry differences

between the sites, is expected to be similar to or better than the DNGS in terms of mixing

performance.

SWE also considered a once-through scenario with a higher discharge temperature (15.6oC) but

correspondingly lower flow (since the required amount of cooling is constant). Their model

confirmed a similar area of mixing zone and similar temperatures in the vicinity of the diffuser

line, apart from the higher temperature at the mouths of the ports. As such, the more

“conventional” 9oC scenario was evaluated and would be considered to bound, or at least

approximate, the 15.6oC option.

For the purpose of the AE assessment of effects, it was considered that the Lake Ontario

nearshore habitat VEC could be further affected, to some extent, by thermal discharge outside of

the Operation and Maintenance Phase mixing zone. Thermal addition within the narrow mixing

zone along the diffuser line was not considered as this area was considered part of the footprint

of the diffuser and it would be appropriate to offset changes to habitat suitability resulting from

scour, high water velocity, turbulence and elevated water temperature as part of a fish habitat

compensation plan for the Project. As such, this assessment focuses on the temperature

conditions in the habitats surrounding the mixing zone. Outside of the once-through mixing

zone, water temperature may be elevated and the suitability of the habitat may be addressed by

considering the likelihood of effects on relevant VEC indicator species.

VEC indicator species vary in their potential to be influenced by the thermal discharge. Since the

discharge diffuser mitigates contact of thermal effluent with the lakebottom, there is little

expectation of effect on benthic and demersal organisms. Lake bottom contact can occur with

4°C water during the winter, and in conjunction with upwelling events in the summer, but this

temperature is similar to lakebottom ambient and is not deleterious to any of the VEC indicator

species during those seasons. For example, round and lake whitefish egg and larval development

are not expected to be significantly affected by temperature changes of this nature in areas

beyond the mixing zone.




3-34

The assessment of thermal effects on VEC indicator species was conducted through comparison

of calculated MWATs to the temperature thresholds for the VEC indicator species. The

assessment was based on the understanding that where the predicted temperature exceeds the

optimal temperature range for a particular fish VEC, there was potential for an adverse effect.

MWAT values were obtained from earlier studies conducted by Romanchuk and Burchat (1997)

which is referenced in the SWE- Existing Conditions TSD. Table 3.3.2-5 summarizes the

maximum change in temperature for bottom sensors placed over the December to April period

(1990-1996) along the perimeter of the mixing zone. During the 1993 to 1996 period 3 to 4

generating units were in operation. Although the data is limited, the estimated per cent of time

when temperature changes exceeded 2oC was typically less than 5%. The potential effects of

thermal discharge on developing whitefish eggs during the winter period were assessed through

detailed laboratory simulation studies (Griffiths 1979, 1980). Temperature rises above ambient

from 2oC to 10

oC were included. In the simulation runs, temperature elevations were applied

continuously, for 75% of the time, or for 25% of the time. Periodic exposure to elevated

temperatures was less deleterious than continuous exposure, but survival declined sharply when

eggs were cycled to temperatures above 7oC. Computations indicated that survival would be

maintained at 75% of expected ambient levels if constant temperature increases were limited to

3.5oC. Periodic increases (25% of time) of 5

oC would have a similar effect. Furthermore,

additional simulations under the worst (warmest) conditions concluded that continuous

elevations above ambient of 0.5oC to 1

oC or periodic (25-75% of the time) elevations of 2

oC to

2.5oC will have little adverse effect. Most of the VEC indicator species, including round

whitefish of all life stages, are benthic or demersal species.

It is also noteworthy that few larval round whitefish were found in surveys conducted in the

spring of 2009 (based on 84 sampling events), and that adult whitefish populations are on the

decline (Hoyle, 2009). Round goby are now the dominant larval benthic species in the vicinity

of DNGS (see Section 3.8 of the AE Existing Conditions TSD).




3-35

TABLE 3.3.2-5

MWAT Above Ambient Values along the Perimeter of the Mixing Zone

December 1990-March 1991 Period

Instrument ID* Bottom Sensors

Maximum Temperature Change

(oC)

Estimated Percent Occurrence

TD 31 0.9 <20 TD 34 2.6 <5 TD 35 2.7 <5 TD 38 1.7 <5 TD 42 1.3 <5 TD 45 2.5 <5 TD 52 1.8 <5 TD 55 2.6 <5 CM 10 2.0 <5

*The locations of bottom sensor along mixing zone are contained in the SWE Existing

Conditions TSD, and Romanchuk and Burchat 1997.

December 1992-April 1993 Period

Instrument ID* Bottom Sensors

Maximum Temperature Change

(oC)

Estimated Percent Occurrence

TD 31 1.4 <5 TD 34 3.2 <5 TD 35 4.0 <5 TD 38 2.3 <5 TD 42 1.5 <5 TD 55 3.3 <5




Instrument ID*

Bottom Sensors

Maximum Temperature

Change

(oC)

Estimated Percent

Occurrence

TD 34 3.1 <5

TD 45 2.4 <5

TD 52 2.1 <5

TD 55 3.3 <5

CM 10 1.9 <5






3-36


Instrument ID*

Bottom Sensors

Maximum Temperature

Change

(oC)

Estimated Percent

Occurrence

TD 31 1.0 <5

TD 34 2.7 <5

TD 35 3.5 <5

TD 42 2.1 <5

TD 45 2.5 <5

CM10 2.5 <5




Instrument ID*

Bottom Sensors

Maximum Temperature

Change

(oC)

Estimated Percent

Occurrence

TD 31 1.2 <5

TD 34 2.7 <5

TD 42 1.7 <5

TD 45 2.4 <5

TD 52 2.2 <5

TD 55 2.9 <5

CM 10 1.9 <5



Winter water temperature conditions in the area surrounding the diffuser mixing zone were little

elevated above ambient nearshore temperatures and were not considered deleterious to any of the

VEC indicator species and their life stages during that season (SWE TSD). This was particularly

evident for whitefish egg and larval development, which could be considered the VEC indicator

species most sensitive to changes in winter water temperatures. This result is expected, given that

the diffuser is designed to mitigate the propagation of extensive thermal plumes and contact of

heated water with the lake bottom by promoting mixing up into the overlying water column.

MWAT values for the summer period were also reviewed to determine whether thermal addition

during the period of highest ambient nearshore water temperatures could elevate water

temperature conditions sufficient to harm fish. The highest MWAT values during summer were

approximately 24oC, and these occurred during the month of August, when background

nearshore water temperature reached the low 20’s. The small temerature difference is ascribed to

the mitigative effect of the diffuser system which, as described above, was designed to promote

rapid mixing of heated water within a relatively small area along the diffuser line. The likelihood

of the highest MWAT to affect the relevant VEC indicator species is presented in relation to

published preferred, optimum and avoidance temperatures (Wismer and Christie 1987) as

appropriate:




3-37

Emerald shiner – the diffuser is in adult shiner habitat. Preferred summer temperature is

22-25oC. Optimum temperature is 24-28.9

oC. Since the maximum MWAT is within these

ranges, no adverse effects of increased temperatures are predicted for emerald shiner.

Alewife – the diffuser is in primarily adult alewife habitat. Juveniles can be found in

warmer inshore waters and have higher temperature tolerances. The maximum MWAT of

24oC is within the adult preferred range of 18.8-28.3

oC and therefore, no adverse effects

on the alewife are predicted.

Salmonid sportfish – none of these fish have spawning or nursery habitat near the

diffuser. The maximum MWAT is above the optimum and upper avoidance temperatures

of the salmonids and could render a portion of the area around the diffuser mixing zone

unattractive to these species during warm water periods in August. However, salmonids

are cold water species that tend to occur in the colder, deeper areas of the lake during the

summer months. As a result, salmonids are not likely to frequent the warm nearshore

waters during the month of August due to generally higher ambient temperatures in these

areas.

3.3.2.5 Comparison of Weekly Maximum Hourly Temperatures (WMHT) to Round Whitefish Temperature Benchmarks

In addition to the MWAT investigation conducted, weekly hourly maximum temperature data

from the DNGS Thermal Plume Study (Romanchuk and Burchat 1997) were compared to round

whitefish temperature benchmarks. These data are the maximum hourly water temperature

recorded in a one week period from temperature dataloggers placed at the bottom of Lake

Ontario, 9 to 22 metres below surface, in the DNGS Thermal Plume Study area (SWE Existing

Conditions TSD). Data from January 1993 to June 1996 were assessed during which period 3 to

4 generating units were in operation. The January to March period is the time interval when most

egg development is expected to occur. This represents an assessment of the worst-case

conditions, since the greatest temperature increase is likely to occur with 3 to 4 units in

operation.

Table 3.3.2-6 shows the various lifestages for the round whitefish as well as the corresponding

temperature benchmarks that were used in this assessment. Egg survival and hatching are the

most sensitive lifestages of the round whitefish and occur in the winter and early spring months.

Consequently, the assessment focused on these early lifestages. The weekly maximum hourly

temperatures (WMHT) recorded in the winter months (Table 3.3.2-7) were compared to the

round whitefish temperature benchmarks for egg survival and hatching (Table 3.3.2-6). The

short–term mortality threshold of 5ºC for embryo survival was selected for this assessment, since

the hourly maximum temperatures represent a short-term acute exposure. Weekly average

temperatures, as discussed in the previous section, are lower, and would represent long-term

chronic exposures that would be assessed against the optimum temperature benchmark.

Lake Ontario ambient water temperatures are not greatly different today compared to when the

data was collected. Tables 3.3.2-8 and 3.3.2-9 show available meteorological data from

Environment Canada weather station at Pearson International Airport for 1993 to 1996 and 2007

to 2009. Year to year variability exists in the mean temperatures and total precipitation, but there




3-38

was no obvious increase in temperature from 1996 to 2009. Therefore, the 1993 to 1996 data

was considered adequate for this analysis.

The one-hour weekly maximum temperatures are worst case scenarios that would only occur a

fraction of the time, but assumed to occur 100% of the time. Where the recorded temperatures

are below the temperature benchmarks for the round whitefish, there is very low probability that

the round whitefish will be impacted by a change in water temperature.

TABLE 3.3.2-6

Maximum Weekly Average Temperatures ( C) for Round Whitefish

Life stage Optimum

temp.

Upper

lethal temp.

Short Term

Mortality

Embryo - - 5

Egg Survival 1-5 - -

Hatching 2.2 - -

Larvae 3 - -

Fry - - -

Juvenile 15a 24.8b -

Adult 15a 24.8b -

Spawning 3 – 4.5 - - a lake whitefish data, unspecified life stage b lake whitefish data, young of the year

All other values are calculated based on data from Wismer and Christie [1987]




3-39

TABLE 3.3.2-7

Weekly Maximum Hourly Temperatures (WMHT) from the DNGS Thermal Plume Study

Data (ºC)

Diff

Start

Diff

End

Mix

Off

Mix

Near

Mix

East

Start

Mix

East

End

Mix

West

Start

Mix

West

End

IntakeSite

TD38 TD35 TD34 TD31 TD52 TD55 TD42 TD45 CM10

Depth 10 12 22 07 10 14 09 10 10

Bottom Yes No Yes Yes Yes Yes Yes Yes Yes

Start Year 1990 1990 1990 1990 1990 1990 1990 1990 1983

End Year 1995 1995 1995 1995 1995 1995 1995 1995 1996

Season Week Start of Week

Winter 1 1/1/1993 3.3 4.4 4.1 2.5 3.8 2.6

Winter 2 1/8/1993 3.2 4.1 3.9 2.3 3.5 2.5

Winter 3 1/15/1993 2.3 3.8 3.4 1.4 2.5 1.6

Winter 4 1/22/1993 3.8 4.4 3.8 2.5 4 3.1

Winter 5 1/29/1993 3.1 4.6 3.3 1.7 3.4 2.1

Winter 6 2/5/1993 2.6 3.7 3.4 1.6 2.7 1.7

Winter 7 2/12/1993 1.9 2.3 1 2 1

Winter 8 2/19/1993 1.7 2.8 1.3 1.9 1.5

Winter 9 2/26/1993 1.5 3.1 1.5 1.7 1.3

Winter 10 3/5/1993 2.3 3.1 1.5 2.5 1.4

Winter 11 3/12/1993 2.3 2.8 1.3 3.3 1.4

Winter 12 3/19/1993 2 3.8 1.8 2.2 1.9

Winter 52 12/24/1993 6.1 4.3 5 4.1 4.4

Winter 53 12/31/1993 1.8 3 2.1 2

Winter 53 1/1/1994 2.6 3.4 2.9 2.8

Winter 54 1/8/1994 1.5 2.1 2.2 1.5

Winter 55 1/15/1994 1.1 1.8 1.4 1.1

Winter 56 1/22/1994 1.3 2 2 1.4

Winter 57 1/29/1994 1.6 2.2 2.2 1.6

Winter 58 2/5/1994 1.4 2.1 2.4 1.4

Winter 59 2/12/1994 1.1 1.6 2.2 1.1

Winter 60 2/19/1994 2 2.3 2.5 2

Winter 61 2/26/1994 1 1.7 1.9 1

Winter 62 3/5/1994 2 2.8 2.7 2.1

Winter 63 3/12/1994 2.4 3 2.6 2.4

Winter 64 3/19/1994 3.2 3.6 3.2 2.7

Winter 104 12/24/1994 5.6 4.3 4 4.7 4

Winter 105 12/31/1994 4.3 3.7 3.4 4.4 3.5

Winter 105 1/1/1995 4.7 4.4 3.3 3.8 3.7

Winter 106 1/8/1995 3.2 2.7 1.7 2.4 2

Winter 107 1/15/1995 3.5 1.7 1.2 2.3 1.2

Winter 108 1/22/1995 4.3 3.4 2.6 3 2.4




3-40

Diff

Start

Diff

End

Mix

Off

Mix

Near

Mix

East

Start

Mix

East

End

Mix

West

Start

Mix

West

End

IntakeSite

TD38 TD35 TD34 TD31 TD52 TD55 TD42 TD45 CM10

Winter 109 1/29/1995 4.1 4.2 3 3.2 2.6

Winter 110 2/5/1995 3.7 2.6 2.2 3.1 1.9

Winter 111 2/12/1995 3.2 2.6 1.6 1.8 1.9

Winter 112 2/19/1995 4.1 3.4 2.5 4.2 2.7

Winter 113 2/26/1995 3.8 4.9 3 3.8 2.9

Winter 114 3/5/1995 3.8 2.6 2.2 2.9 2

Winter 115 3/12/1995 4.5 3.3 3 3.4 2.3

Winter 116 3/19/1995 5.1 4.1 3.9 3.8 3.7

Winter 156 12/24/1995 2.5 3.9 2.2 2.4 2.9 2.1 2.5 2.5

Winter 157 12/31/1995 2.8 4.3 2.2 2.7 3.2 2.4 2.7 2.5

Winter 157 1/1/1996 2.7 4.6 2.4 2.6 2.8 2.7 3.6 2.7

Winter 158 1/8/1996 1.7 3.1 1.6 1.9 2.2 1.7 2.2 1.7

Winter 159 1/15/1996 2 2.8 1.4 1.8 2.2 1.6 2.2 1.5

Winter 160 1/22/1996 2.2 3 1.6 1.9 2.7 1.7 2.7 1.8

Winter 161 1/29/1996 2.5 3.1 1.7 2.6 2.8 2 2.5 2.3

Winter 162 2/5/1996 2 3.3 2.1 2.1 2.4 2 2.2 2.1

Winter 163 2/12/1996 3.1 3.8 1.9 2.6 3.5 2.2 2.7 2.3

Winter 164 2/19/1996 1.7 3.1 1.6 1.4 2.1 1.6 2.4 1.3

Winter 165 2/26/1996 3.3 4.1 2.7 3.3 3.5 2.6 3.2 3

Winter 166 3/4/1996 2.7

Winter 167 3/11/1996 1.5

Winter 168 3/18/1996 2.6

Note: Values shaded in light grey exceed the round whitefish hatching benchmark of 2.2°C.

Values shaded in dark grey exceed the round whitefish short term maximum temperature for round whitefish embryo

survival of 5°C.

As shown in Table 3.3.2-7 and Figure 3.3.2-1, there are only 3 one day exceedances of the short

term maximum temperature for round whitefish embryo survival and these all occurred at one

location (offshore of the diffuser) over the 37 month period evaluated. These temperature

exceedances occurred either early in the winter, as water temperatures were decreasing, or in the

spring, as the lake was beginning to warm up. No exceedances occurred during January or

February, when the eggs and embryos would be undergoing development, and would be most

sensitive to temperature increases. Therefore, it is unlikely that embryo development would be

affected by any changes in water temperature.




3-41

TABLE 3.3.2-8

Mean Air Temperatures Recorded from Environment Canada’s Weather Station at

Pearson International Airport (°C)

1993 1994 1995 1996 2007 2008 2009

January -4 -12.4 -3.1 -6.7 -2.9 -2.1 -8.8

February -8.4 -8.3 -7.3 -5.8 -8.4 -5.3 -3.7

March -2 -0.8 1.9 -2.8 0.4 -1.7 0.8

April 6.6 7.3 4.1 4.4 6.1 9.5 NA

May 12.1 11.8 13.3 11.6 14.3 11.8 13.1

June 17.1 19.1 19.9 18.6 20.8 19.6 17.5

July 21.7 21.5 21.9 19.6 21.3 21.5 -

August 21.1 18.7 21.8 20.7 22.4 19.7 -

September 13.6 15.9 14 16.5 18.4 16.9 -

October 7.9 10 11 9.2 14.2 9 -

November 3.1 5.4 1 0.9 2.6 2.9 -

December -2.7 -0.1 -5.1 -0.4 -2.3 -3.1 -

NA- not available

TABLE 3.3.2-9

Total Precipitation Recorded from Environment Canada’s Weather Station at Pearson

International Airport (mm)

1993 1994 1995 1996 2007 2008 2009

January 70.6 61 133.3 72.6 38.6 58.2 44.4

February 26.6 20.2 20.8 38.2 24.6 107.6 73.6

March 31 51.2 50.8 36.2 33.4 61.6 68.8

April 85.4 96 76.6 101.6 60.8 54.6 NA

May 51.6 78.8 87 90.6 73.6 68.8 60.8

June 133.8 54.4 52.1 118 43.2 110.4 70.2

July 87.7 83 55.4 97.4 47.4 193.2 -

August 39.9 60.1 135.4 48.2 20.8 92.6 -

September 59.2 51.4 27.5 166.2 28.6 83.4 -

October 71 27.4 131.8 75.8 41.2 39.6 -

November 65.2 84.9 121.6 29.8 87.8 79.8 -

December 28.8 51.4 35.8 95.2 92.7 99.8 -

NA- not available

The results of the assessment indicate that under conditions where 3 to 4 units were in operation,

there is no concern with acute exposure of developing eggs or embryos during the critical winter

period. Short-term maximum temperatures were below the temperature threshold, and under

similar operating conditions at NND, no effects on round whitefish development would be

expected to occur.




3-42

FIGURE 3.3.2-1

Weekly Maximum Hourly Temperatures (1993-1996)

0

5

10

15

20

25

1Jan93

5Feb93

12Mar93

16Apr93

21May93

25Jun93

30Jul93

3Sep93

8Oct

93

12Nov93

17Dec93

15Jan94

19Feb94

26Mar94

30Apr94

4Jun94

9Jul94

13Aug94

17Sep94

22Oct

94

26Nov94

31Dec94

29Jan95

5Mar95

9Apr95

14May95

18Jun95

23Jul95

27Aug95

1Oct

95

5Nov95

10Dec95

8Jan96

12Feb96

18Mar96

22Apr96

27May96

Week

Temperature

(°C)

TD31 Near Shore Mix TD42 Diffuser Start West Mix

TD38 Diffuser Start TD52 Diffuser Start East Mix

TD45 Diffuser End West Mix TD35 Diffuser End

TD55 Diffuser End East Mix TD34 Offshore Mix

CM10 Intake Short Term Max Embryo Survival




3-43

The Lake Ontario nearshore habitat VEC will not be substantially affected by the operation of

the CCW discharge diffuser as species are unlikely to be excluded by unsuitable temperatures.

Effective operation of a diffuser, as demonstrated at DNGS, will not substantially affect the VEC

indicator species, either individually or in terms of population conservation, as MWAT and

WMHT values adjacent to the mixing zone are not considered likely to be harmful.

In summary, the operation of the once-through cooling system, as the bounding scenario, will

result in the localized discharge of warmer water. This will be confined to a small mixing zone

around the diffuser. The effects are confined to a small area of the water column around the

diffuser and do not affect critical fish habitat on the lake bottom. Furthermore, the design

promotes mixing and therefore, dissipation of heat. Therefore, the effects due to thermal

discharge are considered to be of negligible overall environmental impact. With its offshore

submerged intake and its offshore multi-port diffuser, DNGS is employing Best Available

Technology in terms of thermal discharge effects (CNSC 2006). Since the existing DNGS

diffuser has been designed to mitigate thermal discharge effects and the NND diffuser will be at

least as effective in minimizing the thermal discharge, it will also employ the Best Technology

Available, in terms of thermal discharge.

3.3.2.6 Thermal Discharge: Cooling Tower Option

The cooling tower option requires a substantially lower flow volume (approximately 2.4%) than

the once-through cooling bounding scenario. Discharge to Lake Ontario from a cooling tower

configuration would employ a diffuser to promote mixing with ambient lake water, thereby

reducing elevated temperatures and development of a thermal plume in the nearshore. The effects

of the thermal discharge on habitat are limited to very moderate water temperature increases in the

immediate area surrounding the diffuser. Since the thermal effects of the once-through bounding

scenario were predicted to be negligible, the considerably lower level of interaction of a cooling

tower configuration with aquatic biota and habitat is also considered to result in only negligible

effects.

3.3.2.7 Lake Infill Structure

The lake infill constructed during the Site Preparation and Construction phase will be a

permanent feature in the nearshore. While habitat loss incurred during construction will be

compensated, lake infills can result in on-going impacts. The Ontario Ministry of Environment

(MOE) (Persaud et al. 2003), identifies potential environmental concerns related to lake infill

structures that include the creation of nuisance conditions where water circulation may be

adversely affected.

Due to the location of the lake infill adjacent to the St Marys Cement site, current patterns in the

nearshore may be altered. These changes may result in reduced water circulation and increased

water temperature at the eastern end of the proposed lake infill. This area also receives inflow

from Darlington Creek that has been noted by SWE to contain higher concentrations of nutrients

in surface water samples from the creek. These conditions may be conducive to enhanced algal

growth possibly to nuisance levels.

Since the effects of the lake infill cannot be predicted in advance with any certainty, and will

depend upon the final configuration of the lake infill, an adaptive management approach will be




3-44

taken to address these concerns. If monitoring indicates that algal growth in this area will be a

problem, then design modifications can be undertaken. These could include further means that

either enhance water circulation to flush nutrients that could contribute to aglal growth, or

alternatively measures to reduce water circulation, favouring the creation of a coastal wetland or

marsh, dominated by vascular plants that would compete with algae for nutrients, thereby

limiting algal growth. Since development along the north shore of Lake Ontario has

systematically reduced the quality and area of these coastal wetland habitats, the creation of

productive new coastal wetland habitat would be a considerable enhancement to the AE. As and

example, creation of a wetland would promote warm water fisheries and waterfowl habitat as a

potential fish habitat compensation plan. Monitoring of the wetland could be incorporated with the

ongoing site biodiversity monitoring plan.

3.3.3 Summary of Effects Advanced for Mitigation

The following Site Preparation and Construction Phase effects were advanced for consideration

of mitigation measures that may be required in addition to the effects management features that

are inherent in the Scope of Project for EA Purposes TSD:

Removal of On-Site Ponds;

Removal of Upper Reaches of Intermittent Tributaries to Darlington Creek;

Alteration/disruption of Coot’s Pond;

Alteration of Upper Reaches of an Intermittent Lake Ontario Tributary;

Lake infill; and,

Construction of Intake and Discharge Structures (including the footprint of the thermal

mixing zone).

The Operation and Maintenance Phase effects of Impingement and Entrainment and Thermal

Discharge have been mitigated by effects management features inherent in the Project design and

have not been advanced for consideration of additional mitigation. However, they are included

below in order to provide a complete summary of both inherent and additional mitigation

measures relevant to AE effects of the Project.

3.4 Consideration of Mitigation and Determination of Likely Residual Effects

Based on the foregoing steps in the assessment process, the interactions between some Project

works and activities and the environment are likely to result in effects on the AE. Adverse

effects were advanced for further consideration of technically and economically feasible

mitigation measures.

Planning for, and application of mitigation measures for environmental effects can take place

both at the time of project planning and design (i.e., as in-design mitigation measures to pre-empt

possible effects); and during the EA process to address those effects identified as likely or

probable during the EA. Both are considered effective means to mitigate the possible adverse

effects associated with a project.

The likely environmental effects of the Project on the AE are described below in Table 3.4-1.

Also included in the table is: i) a description of the applicable features inherent in the Project that




3-45

have been considered in evaluation for their benefit in ameliorating the effects; and, ii) additional

mitigation measures identified during the EA to further diminish or eliminate the likely

environmental effect.

TABLE 3.4-1

Summary of Likely Environmental Effects, In-Design Mitigation Measures and Mitigation

Recommendations

Likely Environmental

Effect

In-Design Mitigation Measures Considered in

the Evaluation

Additional Identified

Mitigation Measures

Access road crossing of

Darlington Creek Sedimentation and erosion controls.

Fish habitat compensation to offset loss of fish

habitat and satisfy requirements of a section

35(2) FA authorization.

Construction of clear span

bridge to avoid in-stream

works.

Re-alignment of access

road to the west to avoid

creek crossing.

Removal of on-site ponds

(Treefrog, Dragonfly and

Polliwog Ponds)

Salvage and re-use/relocation of aquatic plants

and amphibians where practicable.

Additional mitigation not

required.

Removal of Upper

Reaches of Intermittent

Tributaries of Darlington

Creek

Sedimentation and erosion controls to prevent

effects on downstream portions of the tributary

and on the main branch of Darlington Creek.

Site drainage and stormwater management can

maintain contribution of flow within the

Darlington Creek watershed for the north (D2)

tributary.

For the south (E) tributary, site drainage and

stormwater management can contribute flow in a

new channel directed toward Lake Ontario.

Fish habitat compensation, either on-site or off-

site as opportunity allows to offset the loss of

indirect fish habitat and to satisfy requirements

of a section 35(2) FA authorization.


required.

Alteration/disruption of

Coot’s Pond Fish salvage from work areas, depending on

extent of in-water works.

Sedimentation and erosion controls, including

possible settling pond upstream of Coot’s Pond.

Restoration (stabilization, re-planting).


required.

Alteration of Upper

Reaches of Intermittent

Lake Ontario Tributary

Sedimentation and erosion controls

Fish habitat compensation, either on-site or off-

site as opportunity allows to offset the loss of

indirect fish habitat and to satisfy requirements

of a section 35(2) FA authorization.


required.

Lake infill Fish salvage.

Sedimentation and erosion controls.

Fish habitat compensation to offset the loss of

direct fish habitat and to satisfy requirements of

an authorization under section 35(2) of the FA.

Adaptive management

strategy to address

potential nuisance algal

growth. The potential

creation of nuisance algal

growth conditions at the

east end of the lake infill

may require modification

of the design to either

enhance circulation or




3-46


Effect


the Evaluation


Mitigation Measures

encourage the development

of a coastal wetland area.

The lake infill will be

monitored, and if nuisance

algal conditions occur,

design modifications may

be implemented where

practicable. As an

example, the development

of a new coastal wetland

area would be a positive

effect on local productivity

and biodiversity,

particularly since there has

been a considerable loss of

these important habitats

since colonial times.

Construction of Intake and

Discharge Structures Siting of the structures in less sensitive habitat

offshore of more productive nearshore habitats

and spawning areas.

Underwater blasting mitigation methods as per

DFO guidance (e.g., seasonal timing restrictions,

fish deterrence, bubble curtains and design of

charge size, placement and sequencing to

minimize incidental mortality) authorization.

Since the project also results in HADD of fish

habitat, the conditions associated with section 32

authorization under the FA will be included

within the section 35(2) authorization.

Fish habitat compensation to offset the loss of

direct fish habitat and to satisfy requirements of

an authorization under section 35(2) of the FA.

The area of the thermal discharge mixing zone

must also be taken into account as a physical

habitat disruption (primarily turbulence, but also

temperature to some extent) and be included in

the fish habitat offsets or compensation

associated with section 35(2) of the FA

authorization.


required.

Impingement and

Entrainment (I&E) The existing DNGS intake structure has been

designed to mitigate entrainment and

impingement mortality and the NND intake

structure will be at least as effective in

minimizing the impingement and entrainment.

Porous veneer intake structure for once-through

cooling (bounding scenario) to minimize intake

velocity.

Location of the intake structure (once-through

bounding and cooling tower scenarios) in less

sensitive habitat offshore of more productive

nearshore habitats and spawning areas.

Cooling tower option will include fish deterrents


required.




3-47


Effect


the Evaluation


Mitigation Measures

and/or other mitigation to further reduce I&E

losses.

No SARA/ESA species are expected to be

impinged. If impingement occurs, for example

with American eel, an adaptive management plan

will be used to consider other mitigation

measures.

OPG accepts the obligation under the FA to

provide acceptable and adequate

mitigation/compensation measures for the

potential impacts to fish and fish habitat relating

to the NND Project. The final

mitigation/compensation plan will fulfill the

requirements for an authorization under

section 35(2) of the Act (HADD). The final plan

will also contain components that will address

the requirements under section 32 of the

Fisheries Act (for the destruction of fish by any

means other than fishing).

Thermal Discharge Diffuser discharge structure to limit the size of

the mixing zone and dispersion of a thermal

plume.

Location of the discharge diffuser in less

sensitive habitat offshore of more productive

nearshore habitats and spawning areas.


required.

Considering the likely environmental effects of the Project on the AE and the above-noted

mitigation measures identified to ameliorate the effects, the following residual adverse

environmental effects are anticipated:

3.4.1 Access Road Crossing of Darlington Creek

Construction of the Darlington Creek stream crossing using a box culvert, similar to existing

stream crossings, could result in local habitat destruction. Fish habitat compensation, likely as

part of a comprehensive fish habitat compensation plan for the Project, would be required to

offset the HADD (section 35(2) of the FA).

However, effective mitigation strategies exist such that the crossing could be implemented to

avoid HADD. Instead of using a box culvert, and associated fill within the creek valley, a clear

span bridge could be installed. A bridge would avoid in-stream works and would minimize loss

of riparian habitat within the valley. Alternatively, by aligning the road access to the west of the

creek, the need for a crossing could be avoided altogether. Therefore, with appropriate

mitigation, the construction of an access road would have negligible impact on local aquatic

habitat.

3.4.2 Removal of On-Site Ponds (Treefrog, Dragonfly and Polliwog Ponds)




3-48

As the ponds were constructed features, it is reasonable to suggest that similar habitat could be

constructed elsewhere on the DN site to offset the loss. Where appropriate and practicable,

plants, amphibians and incidental invertebrates salvaged from Treefrog, Dragonfly and Polliwog

Ponds could be introduced to the new facilities to accelerate habitat development. Clearing and

grubbing of the existing ponds would have to be scheduled to coincide with construction of the

SWM pond(s). A disposal area could be designed to retain ponds, or portions of them, within any

geotechnical setback that may be required along the CN line and to replace ponds as part of

constructed site drainage features, which will have to be implemented early in the site clearing

and construction schedule. The result would be a negligible residual effect on aquatic habitat

diversity and biodiversity.

3.4.3 Removal of Upper Reaches of Intermittent Tributaries to Darlington Creek

The on-site portions of the intermittent tributaries to Darlington Creek do not support aquatic

plant, fish and invertebrate species. The sensitivity of the Darlington Creek receiving habitat to

contributions of these tributaries is judged to be low, based on physical and habitat factors in the

main branch of the creek. Nevertheless, it is expected that fish habitat compensation may be

required to offset the loss of the “indirect” or “contributing” fish habitat that will be lost. At the

north (D2) tributary, the conveyance function of the lost portion of tributary could be maintained

by site drainage and SWM features. Habitat function at the north tributary could be improved

over existing conditions (row-crop agricultural) as part of compensation for loss of the original

channel. Although it is unlikely that compensation within the south (E) tributary will be feasible,

improvements to habitat quality and productivity could be incorporated into site drainage

features of the NND station area, or generally addressed as part of a comprehensive fish habitat

compensation plan for the NND Project. The result is negligible residual effect on AE features.

3.4.4 Alteration/Disruption of Coot’s Pond

Coot’s Pond is not well-connected to adjacent aquatic habitat. It is a relatively isolated SWM

pond facility. The extent of alteration or disruption of portions of Coot’s Pond will be kept to a

minimum during the Site Preparation and Construction Phase to protect the existing wetland and

open water habitats. Affected areas could be isolated, if necessary, and fish and other wildlife

transferred to unaffected portions. Restoration of affected Coot’s Pond features will occur

following the Site Preparation and Construction Phase and may include soil/bank stabilization

and replanting of wetland and riparian vegetation. This change is considered negligible in terms

of on-site AE features.




3-49

3.4.5 Alteration of Upper Reaches of Intermittent Lake Ontario Tributary

Changes to the intermittent Lake Ontario tributary near Coot’s Pond are limited in scope to

possible realignment or filling of some reaches to accommodate activities associated with use of

the existing construction waste landfill. Similar to the Darlington Creek tributaries, this

watercourse is assessed as likely constituting only indirect fish habitat in the areas that could be

affected. Mitigation of any adverse effects would likewise be addressed as part of a

comprehensive fish habitat compensation plan for the NND Project, which would offset the

changes with negligible net effect.

3.4.6 Lake Infill

Replacement of 40 hectares of Lake Ontario nearshore habitat with lake fill will affect the

amount of habitat available to VECs on the DN site and, to a lesser degree, Local scales. Direct

mortality associated with lake infill is likely to be limited primarily to benthic invertebrates and

round goby VEC indicator species as they cannot be feasibly salvaged. Other VECs in the fill

area will be salvaged. The primary effect is the loss of habitat for VEC indicator species and

other species. However, granting of a section 35(2) FA authorization by DFO will involve the

design and implementation of appropriate compensation measures that will offset the loss of

habitat. The result is negligible residual effect on AE features, including Lake Ontario nearshore

habitat VEC and the VEC indicator species. Although the lake infill results in no residual effect,

it will be carried forward for significance assesment in the EIS.

The potential creation of nuisance algal growth conditions at the east end of the lake infill may

require modification of the design to either enhance circulation or encourage the development of

a coastal wetland area. The lake infill will be monitored, and if nuisance algal conditions occur,

design modifications may be implemented where practicable. The development of a new coastal

wetland area would be a positive effect on local productivity and biodiversity, particularly since

there has been a considerable loss of these important habitats since colonial times.

3.4.7 Construction of Intake and Discharge Structures

Incidental mortality of limited numbers of individuals of a few VEC indicator species could

occur due to blasting, however this effect is mitigable with measures that can be undertaken in

the blasting program design and specific measures that can reduce the presence of fish in the

blast area or reduce the propagation of harmful shock waves through the water. Underwater

blasting will be subject to DFO authorization under section 32 of the FA (covered within

authorization of section 35(2) of the FA since HADD of fish habitat), and is expected to include

development of mitigation strategies to minimize harmful effects on fish. The residual effect on

VEC indicator species is considered negligible.

The small area of habitat that will be lost in association with the once-through cooling bounding

scenario, including the intake structure site (approximately 1.1 hectares) and discharge diffuser

alignment (approximately 0.7 hectares), will be offset by fish habitat compensation measures that

will accompany a section 35(2) FA authorization. In addition, the area of the diffuser mixing

zone must also be included in the derivation of fish habitat compensation requirements, as it will




3-50

represent a physical disruption of the habitat beyond the installation and presence of the

discharge ports (i.e., turbulence and elevated temperatures in the mixing zone throughout the

Operation and Maintenance Phase). The residual effect on the Lake Ontario nearshore habitat

VECs and the VEC indicator species is considered negligible.

3.4.8 Impingement and Entrainment

As the bounding scenario includes a once-through CCW system at the NND station with a

porous veneer intake structure placed beyond the most productive nearshore areas in at least

10 meters of water, effective mitigation of impingement and entrainment will be achieved

without the need for additional mitigation measures. Small numbers of aquatic organisms will be

impinged or entrained at the NND station, but the residual effect is considered negligible in

terms of population abundance and conservation.





components that will address the requirements under section 32 of the Fisheries Act (for the

destruction of fish by any means other than fishing).

3.4.9 Thermal Discharge

As the bounding scenario includes a once-through CCW system at the NND station with an

offshore discharge diffuser aligned perpendicular to shore in 10 to 15 meters of water, effective

mitigation of thermal effects on the aquatic habitat VECs and VEC indicator species will be

achieved without the need for additional mitigation measures. A relatively small area of Lake

Ontario will serve as a mixing zone beyond which water temperature will be effectively

indistinguishable from ambient conditions. As such, the residual effects on the Lake Ontario

nearshore habitat VEC and the VEC indicator species are considered negligible.

3.5 Potential Consequence of Climate Change on Predicted Effects

Climate change is expected to have some impact on the Aquatic Environment. The potential

consequences of climate change relevant to the predicted effects of the Project on the Aquatic

Environment primarily surround changes to Lake Ontario water temperature and levels (e.g.,

Lake Ontario surface mixed layers expected to increase by approximately 3-5ºC by 2050 due to

warmer air temperatures (Lehman 2002), net basin runoff decreases of 25 to 50% in the Great

Lakes (Environment Canada 1990; CICS 2000); and the subsequent effect on VECs.

Likely effects on VECs as a result of the Project that may be additionally affected by these

potential consequences of climate change are:

increased algae growth and entrapment due to less mixing of the nutrients from

Darlington Creek, warmer temperatures and the protected nature of the embayment;




3-51

localised loss of some VEC species as a result of cooling/service water intake and

discharge structures; and

impingement and entrainment of aquatic biota as a result of once-through lake water

cooling option and the cooling tower option.

As per the discussion presented below, the potential consequences of climate change are not

expected to substantially alter the predictive effects assessment completed for the Aquatic

Environment.

Increased Algae Growth

Potential consequences of climate change include attached algae growth; expected to increase

especially during the early spring periods at the eastern end of the proposed infill in the vicinity

of St. Marys Cement with increased water temperature and decreased water circulation. This

could result in a change in the amount (e.g., larger) biomass of algae becoming detached. The

proposed mitigation for this predicted effect is an adaptive management strategy to address

potential nuisance algae growth for this location. This strategy will include the potential

consequence of a change in amount of algae detachment.

Loss of Species, Impingement and Entrainment of Biota

Reduced flow from the general watershed may cause water levels in Darlington Creek to

decrease. This may result in a lower fisheries productivity of the Creek which would mainly

impact warm water species such as common carp and white sucker. However, at present,

Darlington Creek is not a very productive fisheries tributary.

Water temperature elevations may cause changes to occur in the general fisheries community of

Lake Ontario. There may be a disappearance of some resident species which may be replaced by

other invasive species. Furthermore, fish year class strength and fish community structure is

expected to change with increased temperature. In a review of expected fisheries changes in the

Great Lakes basin due to global warming, Casselman (2002) predicted a decreasing recruitment

of cold and coolwater species (e.g., lake trout, alewife), and increasing relative recruitment of

warmwater species (e.g., smallmouth bass). The proposed mitigation for this predicted effect is

to adapt the design and location of both the proposed diffuser and intake structures accordingly.

It is expected that this mitigation measure will be applicable to a changed fish community

structure and/or species.

3.6 Section 35(2) Proposed Compensation Plan

In accordance with DFO Policy of the Management for Fish Habitat (DFO 1986), with specific

reference to the principle of ‘No Net Loss of the Productive Capacity of Fish Habitat’, OPG

agrees to undertake measures to compensate for and mitigate against, the loss of fish habitat

arising from the New Nuclear at Darlington (NND) Project. OPG has initiated the process by

submitting an Application for Authorization for Works or Undertakings Affecting Fish Habitats

to DFO (September 30, 2009) and will continue to work with DFO to complete the compensation




3-52

plan which will be incorporated into a subsection 35(2) authorization. The final

mitigation/compensation plan will fulfill the requirements for an authorization under section

35(2) of the Act (HADD). The final plan will also contain components that will address the

requirements under section 32 of the Fisheries Act (for the destruction of fish by any means other

than fishing).

OPG in consultation with the DFO, MNR and CLOCA have developed a list of potential options

that may be used to form the compensation plan.

The objectives of the options were determined to be:

1. Favour the target fish species. While both the predator populations and the forage fish

populations have decreased in recent years, the most effective means by which to ensure

the long term survival and increase of all target fish populations of the lake would be to

focus preferentially on increasing the forage base. Options would consider increasing the

predator base.

2. Meet requirements for the area affected by the project that could provide habitat of a

quality necessary to successfully achieve the objectives of the plan.

3. Based on input from Clarington (the host municipality), it is preferred to focus on

potential compensation sites close to the project, preferably within the boundaries of the

Regional Municipality of Clarington.

The potential options identified are provided in Appendix B.

The assessment has concluded that the Project will not result in a residual adverse environmental

effect on Aquatic Habitat because of the mitigation measures that will be implemented.

However, there may be a perception that the loss of aquatic habitat as a result of lake infilling

and the construction of the intake and discharge structures will result in a residual adverse effect,

notwithstanding that mitigation measures will ensure there is no net loss of nearshore aquatic

habitat. For this reason, therefore, the following is advanced for consideration of significance as

if it was, in fact, considered a residual adverse effect:

Loss of approximately 40 ha of Lake Ontario nearshore aquatic habitat as a result of lake

infilling and a further 2 ha (approximately) as a result of construction of cooling water

intake and discharge structures.

3.7 Ecosystem Dynamics –Invasive Species

Invasive species have changed and are continually changing the dynamics of the Great Lakes,

especially in the nearshore environment (State of the Great Lakes Ecosystem 2007). Some of

these changes include the following:

Alewife: A marine invasive species which entered Lake Ontario in the late 1870’s and the upper

Great Lakes much later around 1931 (Scott and Crossman 1998). Alewife is a dominant species




3-53

in the nearshore environment in the SSA and the major species entrained and impinged at DNGS

(see AE Existing Conditions TSD).

Zebra Mussels: First reported in Lake St. Clair in 1988 (Hebert et al. 1989), but were well

established in the Great Lakes in the early 1990’s. Recent benthic and video surveys (2008,

2009) indicated the proliferation of the species along the proposed lake infill shoreline in the

SSA (AE Existing Conditions TSD).

Round Goby: First reported in St. Clair River in 1990 (Jude et al. 2002) and remained confined

to the river until 1993, is now a dominant species in all Great Lakes (e.g. Lederer et al. 2008).

Recent larval fish and fish community studies in the spring of 2009 indicated the importance of

this species in the SSA (see AE Existing Conditions TSD).

Bloody Red Shrimp: First reported in the Canadian side of Lake Ontario in September 2007

(Marty 2007). Results of a 2009 spring survey indicated the presence of this species in the SSA

(first reported case in the vicinity of DNGS, see AE Existing Conditions TSD).

The future is hard to predict but will certainly be changing over time. The near term is not a

prediction of the potential future locally diverse aquatic ecosystem.


Environmental Assessment Assessment of Environmental Effect


4-1

4. REFERENCES

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Ager, D.D., Cord, I., and P.H. Patrick 2006. Entrainment Sampling At Darlington Nuclear

Generating Station – 2006. Report NK38-REP-07264-10002-R00. Prepared for Ontario

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Ager, D., Cord, I., and P.H. Patrick 2005. Entrainment Sampling At Darlington Nuclear

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The Canadian Institute for Climate Studies (CICS) 2000. Climate Change and Environmental

Assessment, Part 2: Climate Change Guidance for Environmental Assessment, Appendix A - Summary of Projected Regional Climate Change Impacts.

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by Golder Associates, submitted to CNSC, Ottawa ON.

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productivity of warmwater, coolwater and coldwater species in the Great Lakes basin.

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territories-territoires/on/pdf/os-eo05_e.pdf

Dunning, D.J., Ross, Q.E., Geoghegan, P., Reichle, J., Menezes, and J. Watson. 1992. Alewives

Avoid High Frequency Sound at a Power Plant Intake on Lake Ontario. North Amer. J.

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ESG International Inc. 2001. Darlington Nuclear Generating Station Ecological Effects Review.

NK38-REP-0722.07-10001 R000. Ontario Power Generation Inc.

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Study at the Consumers Energy J.H. Campbell Plant. Prepared for Blasland, Bouck and

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Griffiths, J.S. 1979. Potential Effects of Unstable Thermal Discharges on Incubation of Lake

Whitefish Eggs. Ontario Hydro Research Divisions Report No. 79-521-K.




4-2

Griffiths, J.S. 1980. Potential Effects of Unstable Thermal Discharges on Incubating Round

Whitefish Eggs. Ontario Hydro Research Division Report 80-140-K.

Haymes, G.T. and D.P. Kolenosky. 1984. Distribution and Characteristics of Spawning Round

Whitefish in Lake Ontario, 1976-1981. Ontario Fisheries Technical Report Series No. 14.

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Hebert, P.N., Muncaster, B.W. and G.L. Mackie. 1989. Ecological and Genetic Studies on

Dreissena polymorpha (Pallas): A new Mollusc in the Great Lakes. Can. J. Fisheries and

Aquatic Sciences. 46:1587-1591.

Honeyfield, D. 2009. Personal Communication. Scientist, Northern Appalachian Research

Laboratory, Wellsboro, PA.

Hoyle, Jim. 2009. Personal Communication. Assessment Biologist Lake Ontario Management

Unit (LOMU), Ministry of Natural Resources.

Jude, D.J., Reider, R.H. and G.R. Smith 1992. Establishment of Gobiidae in the Great Lakes

basin. Can. J. Fish. Aquatic. Sci. 49: 416-421.

Kissel, R. 1997. Condenser Cooling Water Diffuser Performance. Ontario Hydro Nuclear.

Darlington NGD. Report NK38-REP-07000-003-R00-(P).

Lake Ontario Committee (LOC) 2009. State of Lake Ontario 2008. FMZ Council Presentation.

Lake Ontario Management Unit (LOMU) 2007. 2006 Annual Report of the Lake Ontario

Management Unit. Prepared for the 2007 Combined Upper and Lower Great Lakes

Committee Meetings, Great Lakes Fishery Commission. Queen’s Printer for Ontario,

Picton, ON.

Lederer, M., Janssen, J., Reed, T. and A. Wolf. 2008. Impacts of the Introduced Round Goby

(Apollonia melanostoma) on Dreissenids (Dreissena polymorpha and Dreissena

bugensis) and on Macroinvertebrate Community between 2003 and 2006 in the Littoral

Zone of Green Bay, Lake Michigan. J. Great Lakes Res. 34:690-697.

Lehman, J, 2002. Mixing Patterns and Plankton Biomass of the St. Lawrence Great Lakes under

Climate Change Scenarios. J. Great Lakes Res. 28(4): 583-596, International Association

of Great Lakes Research.

Maher, J.F.B. 1980. Location of the Darlington GS Cooling Water Intake With Respect to the

Distribution of Aquatic Biota.

Marty, Jérôme. (2007) Biological Synopsis of the Bloody Red Shrimp (Hemimysis anomala).Can. MS Rpt. Fish. Aquat. Sci. Draft. 36p.

Minns, C.K., Meisner, J.D., Moore, J.E., Greig, L.A. and R.G. Randall. 1995. Defensible

Methods for Pre- and Post-Development Assessment of Fish Habitat in the Great Lakes.




4-3

I. A Prototype Methodology for Headlands and Offshore Structures. CanadianManuscript Report of Fisheries and Aquatic Sciences. 2328 (1995): xiii+65 p.

Minns, C.K. Quantifying “No Net Loss” of Productivity of Fish Habitats. Canadian Journal of

Fisheries and Aquatic Sciences. 54 (1997): 2463-2473.

Minns, C.K., Moore, J.E., Stoneman, M. and B. Cudmore-Vokey. Defensible Methods of

Assessing Fish Habitat: Lacustrine Habitats in the Great Lakes Basin – Conceptual Basis and Approach Using Habitat Suitability Matrix (HSM) Method. Canadian Manuscript

Report of Fisheries and Aquatic Sciences. 2559 (2001): viii+70 p.

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Entrainment Characterization Study at the Donald C. Cook Nuclear Plant. Prepared for

American Electric Power Bridgman, MI.

Owen, R.W., O’Gorman, R. and S.R. LaPan. 2003. Status of Major Prey Fish Stocks in the US

Waters of Lake Ontario. NYSDEC Lake Ontario Report.

Patrick, P.H., and S. Rkman-Filipovic 2004. Space Perception of Fish in Reference to WE’s

Proposed Porous Dike Concept. Kinectrics Report No. K-010259-001-RA-0010-R00.

September.

Patrick, P.H. and S. Poulton 1993. Effectiveness of the Porous Veneer Intake at Excluding Fish

at Darlington – Sonar and Video Evaluations 1993. Report NK38-07000-T10.

Persaud, D.,, Hayton, A., Jaagumagi, R. and G. Rutherford. 2003. Fill Quality Guidelines for

Lakefilling in Ontario. Ont. Ministry of the Environment Report. ISBN 0-7729-9329-7.

March 2003.

Romanchuk, M.E. and W.L. Burchat 1997. Thermal Plume Study – Darlington NGD – Lake

Ontario – 1990-1996. Report: R-NK38-02740-0003.

Scott, W. B. and E. J. Crossman. 1998 (Editors). Freshwater Fishes of Canada. Galt Mouse

Publication, Oakville. ON. 966 p.

SENES Consultants Ltd. 2009. Biological Liability Losses of Environmental and Impinged Fish

at the Intake Structure of Darlington Nuclear Generating Station. NK54-REP-07730-

00031.

SPDES Biological Monitoring Report 2004. James A. FitzPatrick Nuclear Power Plant (Permit

No. NY 0020109, Section 10, CP-04.03). May 2005.

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Environmental Protection Agency. EPA 905-R-07-003.

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Darlington NGS. Data Report NK38-07015-6. Prepared for Ontario Hydro.




4-4

Tarandus. 1998. The Evaluation of fish Communities in Armoured and Natural Habitats in the

Vicinity of the DNGS. OPG Report NK38-REP-07000-016-ROO.

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Report No. NK38-REP-07000-006-R00-(P).

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Verification. Report NK38-REP-07000-013-R00. Ontario Hydro.

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Data Compilation. Great Lakes Fishery Commission, Ann Arbor, MI.

Wright, D.G., and G.E. Hopky 1998. Guidelines for the use of explosives in or near Canadian

fisheries waters. Can. Tech. Rep. Fish. Aquat. Sci. 2107: iv + 34p.




APPENDIX A

NEW NUCLEAR - DARLINGTON - EA BASIS TABLE




A-1

New Nuclear - Darlington - Basis for EA

Project Phase / Works

and Activities

Description

Site Preparation Phase

Mobilization and

Preparatory Works

Mobilization (construction workforce and equipment): will involve mobilization of equipment and the construction workforce to the site. The

physical aspects of mobilization will involve the establishment of parking areas for staff and equipment, service areas for construction offices,

construction phase fencing for security and safety and equipment storage; security/guardhouse and reception facilities.

Clearing and Grubbing: Vegetation within areas of future construction will be removed. A variety of methods including the removal of trees by

truck, chipping of smaller vegetation and grubbing with a dozer or excavator will be used to remove vegetation. Environmental effects

management measures will be applied throughout the activity such as minimizing the area to be cleared to the extent feasible and complying with

seasonal constraints and regulatory requirements for clearing operations.

Installation of Services and Utilities: includes temporary services and utilities required during construction and permanent services and utilities

required to support operations. Wherever possible, utilities and services will be installed to accommodate the needs of both construction and

operation phases. Utilities and services will include: i) potable water; ii) sanitary sewage collection discharging to a municipal water pollution

control plant; iii) electrical and telephone service; iv) P.A. system; v) fencing. Excavation to install services is captured by other earthmoving

activities.

Development of Roads and Related Infrastructure: includes improvements to access into the site and features to provide for temporary (i.e.,

during construction) and permanent (during operations) access, egress and parking. Onsite roads and infrastructure will include local access roads

and parking facilities within the site to accommodate workforce-related and other traffic during both construction and operation phases. For EA

purposes, it is assumed that off-site parking facilities may be used with workers transferred to the NND via shuttle bus.

Excavation and Grading Excavation and grading will comprise all earth and rock-moving activities including earthmoving and grading, drilling and blasting. Excavation

activities will be conducted in-the-dry with dewatering where required. Collected water will be managed and discharged as described in

Management of Stormwater.

On-Land Earthmoving and Grading: During site preparation activities, effectively all land area east of Holt Road will be disturbed to a large

extent. Topsoil stripping will be by means of suitable earthmoving equipment (e.g., scrapers, excavators and trucks). Excavated soils transferred

to the Northeast and Northwest Landfill Areas and lake infill will be placed using good management practices that address surface erosion, dust

control and related aspects including noise and vehicle emissions.

Transport of Surplus Soil to Off-site Disposal: Should it be necessary to do so, surplus soil will be transported to disposal at an off-site

location(s). The destinations for this material have not been determined, however, it is intended that the material be used to rehabilitate extraction

pits and quarries or other development sites, or similar beneficial use.

Rock Excavation and Grading (Drilling, Blasting, Boring): will involve the excavation and grading of rock and like material, and associated

activities such as drilling or blasting to facilitate its excavation and transfer to rock fill areas (i.e. lake infill) or disposal areas.

Development of Construction Laydown Areas: will include specific areas identified for, and developed as, staging areas for contractor

operations and storage areas for construction equipment and materials. Laydown areas will be graded, temporarily fenced, and surfaced,

depending on function, with granular or asphalt.




A-2


and Activities

Description

Marine and Shoreline

WorksMarine and Shoreline Works includes all works and activities conducted within or adjacent to Lake Ontario such that they are likely to interact

with the marine and aquatic environment. Marine and shoreline-related works and activities will include the following:

Lake infill and Shoreline Protection: will occur throughout an area of Lake Ontario and will extend from the easterly limit of the DN site to

approximately the DNGS intake channel; and about 100 m into the lake on its westerly limit to approximately 450 m on its easterly limit. Lake

infill will create a new landform of up to approximately 40 ha. The lake infill operation will begin with the construction of a low-permeability

coffer dam on its outer perimeter to contain the deposit lake infill materials and isolate the area from lake water intrusion. The core would

typically consist of low-permeability soils or compacted granular materials, driven or vibrated steel sheeting, or drilled caissons. The lake-facing

surface of the dam will be covered with armour stone placed by crane on the lake side of the dam. Any fish within the area to be dammed will be

directed out of the work area by progressive seining and other appropriate means as the dam is placed. Once the cofferdam is complete, the water

contained within it will be pumped out and discharged to Lake Ontario. The material placed within the cofferdam to create the new landform will

originate on-site and be placed as part of the Excavation and Grading activity.

Construction of Wharf: a wharf will be developed in a portion of the lake infilled area generally in front of the Power Block. The wharf will be

used during construction for off-loading oversize and over-weight components and its construction will be appropriate for this purpose.

Lake Bottom Dredging: dredging activities are expected to be minimal, but may be required at the point where the cooling water intake tunnel

daylights to the lake bottom. Any such minor dredging will involve conventional equipment designed and operated for the purpose (suction and/or

mechanical). All dredged sediment will be placed into barges and subsequently off-loaded and disposed of in the Northeast Landfill Area or

existing onsite construction landfill.

Development of

Administration and

Physical Support

Facilities

Administration and Support Facilities comprise various buildings housing staff, equipment and operations necessary to provide ongoing support to

the NND. These will include offices, workshops, maintenance, storage and perimeter security buildings, and utilities operating centres. All such

buildings will consist of conventional steel and masonry structures.

Construction Phase

For assessment purposes, it is assumed that the entire site will be prepared for construction at the outset. Construction of the nuclear power plant elements (i.e., construction

phase) will begin as soon as possible into the site preparation activities and accordingly, the site preparation and construction phases will overlap in time. This is a bounding

assumption since it represents the greatest amount of related work in the shortest period of time.

Construction of Power

BlockThe Power Block includes the reactor building, the turbine-generator building/turbine hall (powerhouse) and related structural features that are

physically associated with them. Development of the Power Block includes the installation of all power generation equipment within it, including

the reactors, primary and secondary heat transport components, and all powerhouse components including turbines, generators and heat

exchangers and pumps and standby power systems. Supply of construction materials and operating equipment to the site is included in the

Construction Material and Operating Equipment Supply.

Foundations will extend into bedrock and may require drilling and blasting. Some elements of construction will be further supported on steel piles.

Above-grade construction will involve techniques typical of heavy industrial development. Placement will involve extensive use of heavy

equipment, including heavy-lift fixed and mobile cranes. Installation of operating equipment will involve movement and placement of large and

specialty components using various standard and extraordinary procedures, depending on the size and weight of the component.




A-3


and Activities

Description

Construction of Intake

and Discharge Structures Intake and Discharge Tunnels and Structures for Once-Through Lake Water Cooling: For EA purposes, the once-through cooling water

intake and diffuser structures at NND are assumed to be similar to the existing structures at DNGS, although appropriately sized to accommodate

the required water flow rates at NND. The tunnels at DNGS were constructed using typical underground mining techniques involving blasting and

excavation. Tunnels for once through cooling water at NND may alternatively be constructed by boring using a purpose-built tunnel boring

machine (TBM).

Intake and Discharge Structures for Cooling Tower Water Makeup and Service Water: Although the water from both mechanical draft and

natural draft cooling towers is recirculated, some make-up water is required to replace tower blowdown and other losses (e.g., evaporation) and for

plant service water needs. This water will be drawn from Lake Ontario via intake and discharge pipelines. The open-cut drill-and-blast method is

likely to be used to excavate a trench to place the intake or outfall pipe. Pipes will be placed in trenches and backfilled with a granular material,

and armour surface protection. Screens may be used to prevent debris from entering the intake structure. Both the intake and discharge structures

for makeup water and service water will be substantially smaller than those required for once-through lakewater cooling due to the smaller

associated water volumes.

Construction of Ancillary

Facilities Ancillary facilities include all features necessary to support operations of the reactors and generation of electricity, although not physically

associated with the power block. Clearing and grubbing and major earthmoving and grading to accommodate development of the ancillary

features are included in the Mobilization and Preparatory Works, and the Earthmoving and Grading activities, respectively.

Expansion of Existing Switchyard: will involve the physical enlargement of the footprint of the existing DNGS switchyard, an increase to the

electrical capacity to accommodate its use for NND, and its connection to the existing electrical grid. The switchyard expansion will effectively be

as an easterly extension to the existing switchyard.

Cooling Towers – Mechanical Draft: includes the towers and the associated infrastructure to support their operation. Mechanical draft cooling

towers are typically shorter in height and larger in footprint than natural draft cooling towers. Construction of the towers will involve conventional

techniques and materials, primarily steel framing, concrete and masonry, and mechanical and electrical components.

Cooling Towers – Natural Draft: includes the towers and associated infrastructure to support their operations. Up to two natural draft towers

may be constructed for each unit (depending on the design). The towers will have a hyperbolic shape. The towers will be constructed of steel

reinforced concrete with structural, mechanical and electrical components and will be erected by means of traditional construction methods (e.g.,

slip forming, crane lifts), and conventional construction materials.

Cooling Towers – Fan Assisted Natural Draft: are not included in any of the three model plant layout scenarios considered in the EA. Because

they are a variation of the two cooling tower types that are considered, their potential interfaces with the environment during construction are

considered to be bounded by the cooling tower options that are addressed in the EA. Fan assisted natural draft cooling towers have a slightly

larger base dimension than the natural draft cooling tower, and have fans placed around the base of the tower to increase the air flow rate. These

towers have a similar hyperbolic shape as a traditional natural draft tower, but approximately the height.

Cooling Tower Blowdown Ponds: For each of the cooling tower options one or more blowdown ponds may be required to receive and treat

blowdown from the towers. Blowdown is the portion of the circulating water flow that is removed in order to maintain the amount of dissolved

solids and other impurities at acceptable levels. The ponds would be excavated into the ground surface and lined (e.g., with clay or synthetic

materials) to ensure proper containment. The ponds will be sized to accommodate the required volume for the system, and the water would be

appropriately treated to comply with discharge water quality criteria, prior to discharge.




A-4


and Activities

Description

Construction of

Radioactive Waste

Storage Facilities

Radioactive Waste Storage Facilities comprise used fuel dry storage facility to house containerized used fuel bundles following their removal from

wet storage in the used fuel bays. Low and Intermediate Level Waste Storage building(s) may also be required. For EA purposes, it is assumed

that a used fuel dry storage building for NND will not be required until approximately 2025, though a storage building for Low and Intermediate

Level Waste will likely be required starting in 2017.

Common to Site Preparation and Construction – Works and Activities

Management of

Stormwater As the site is developed, ditches and swales will be constructed to collect and convey surface water to stormwater management ponds and

ultimately to discharge to an existing drainage course or Lake Ontario. Stormwater management features will be developed to address the

requirements for runoff control both during site preparation and construction (temporary) and during operations (permanent). Wherever possible,

stormwater management features will consider the needs of both construction and operation phases.

Supply of Construction

Equipment, Material and

Operating Plant

Components

Supply of construction materials and operating equipment includes the delivery to the site, of all necessary materials and components for

construction of NND. While much of the material that will be delivered to the site will be via the road network, large components may be

delivered by rail (to an existing rail siding on a neighbouring property and then transported overland to the site or to a new rail siding on the DN

site), or by barge to the new wharf.

Rock Delivery for Cofferdam: delivery of imported rock for cofferdam construction is estimated to be up to 200 trucks per day.

Construction Equipment: comprises all mechanized and related equipment required to support construction. Heavy earthmoving equipment will

be typical of large-scale construction projects (e.g., trucks, dozers, loaders, excavators, scrappers, graders, compactors).

Aggregate and Concrete: For EA purposes, it is assumed that ready-mixed concrete will be provided by an offsite supplier operating on a nearby

property, or is mixed on site in a concrete batch plant. Approximately 750,000 to 1,000,000 m3 of concrete will be required for 4 units.

Manufactured Construction Materials: will include items associated with site preparation (e.g., precast concrete structures, culverts and utility

piping, fence), structural components for buildings and other facilities (e.g., fabricated steel products, masonry), mechanical and electrical

components for buildings and facilities, and various sundry items (e.g., interior finish components). All manufactured construction materials will

be delivered to the site via highway-licensed trucks travelling on provincial and municipal roads, by rail, or by barge. Aside from concrete, the

largest single quantity of material that will be delivered to the site will be structural steel (rebar etc). Approximately 150,000-200,000 tonnes of

structural steel would be required for 4 units.

Plant Operating Components: are fixtures and components associated with an operating nuclear plant. These will include conventional items

(e.g., pumps, turbines, electrical power systems) as well as those that are unique to nuclear plants (e.g., calandria). Most operating components

will be delivered to the site via highway-licensed trucks travelling on provincial and municipal roads. Some oversize items will require special

permits and transport provisions, and others are likely to be transported to the site by rail or via barge and off-loaded at the purpose built wharf.




A-5


and Activities

Description

Management of

Construction Waste,

Hazardous Materials,

Fuels and Lubricants

Construction waste: will be transferred from the site to disposal or recycling at appropriately-licensed waste management facilities. This activity

does not include disposal of excavated spoil (see Excavation and Grading). The existing on-site DNGS construction landfill may also be reopened

for the disposal of construction waste.

Hazardous Materials: (e.g., solvents, chemicals, compressed gases) associated with site preparation and construction will be managed, including

storage, use and disposal, in compliance with applicable legislation, codes and practices. These materials will include expired chemicals, cleaners,

paint, aerosol cans and electrical components. Non-radioactive oil and chemical wastes will be removed from the site for disposal.

Fuels, Lubricants and Chemicals: those required for mechanical construction equipment will be delivered to the site in appropriately-qualified

vehicles and/or containers, stored in purpose-built facilities, and dispensed and used, all in compliance with applicable legislation, codes and

practices. Contingency plans for a detailed response system in the event of a spill will be developed.

Work Force, Payroll and

PurchasingSite preparation and construction will require a contractor labour force that will vary in size throughout the work based on the scope and nature of

the activities underway at any given time. This activity will represent the daily transportation-related aspects of workforce commute as well as the

economic aspects associated with payroll and construction-related capital purchases. The labour force will peak, in the early years of the Project,

at approximately 3,800. In later years of the site preparation and construction phase, the workforce involved in the construction of units 3 and 4

will overlap with staff operating units 1 and 2 and will peak at approximately 5,200.

Operation and Maintenance Phase

Prior to the start of the Operation and Maintenance Phase, commissioning activities will be undertaken including the testing of systems and components. Nuclear fission

reactions in the reactor core will be increased in a controlled manner until criticality is achieved. Reactor power will then be increased in a controlled manner. Steam will be

admitted into the turbine and the steam and feedwater system will be placed into service. The unit’s electrical generator will be connected, or synchronized, to the electrical grid.

Maintenance, both routine and major, is included in this phase of the Project. Three general areas of maintenance are performed: preventative maintenance, corrective

maintenance, and improvement or upgrade activities (including during planned shutdowns and outages).

Operation of Reactor

Core

The reactor consists of the reactor assembly and reactivity control devices. The reactor core is the starting point for the generation of radioactivity.

All other systems in the nuclear power plant (NPP) work to support the reactor core. This activity includes operation, startup, shutdown, and

maintenance, testing and modification of the reactor core components, including the maintenance required for refurbishment. Nuclear malfunction

and accident considerations will originate here.

In an ACR-1000 reactor the horizontal calandria vessel is axially penetrated by calandria tubes. The calandria tubes provide access through the

calandria vessel to the fuel channel assemblies containing nuclear fuel bundles of varying fuel enrichments.

In the EPR and AP1000 reactors, a pressure vessel contains vertically oriented assemblies of fuel rods called fuel assemblies. The assemblies,

containing various fuel enrichments, are configured into the core arrangement located and supported by the reactor internals. The reactor internals

also direct the flow of the coolant past the fuel rods.




A-6


and Activities

Description

Operation of Primary

Heat Transport System

The function of the primary heat transport system is to move heat from the reactor core into the primary side of the steam generator. This system

will generate L&ILW (such as filters and ion exchange resins). This is captured in the Waste Management work activity. Maintenance of this

system includes periodic chemical cleaning of the steam generators and replacement of parts during refurbishment and is included in the Major

Maintenance work activity. Water losses are captured under the ventilation and drainage project works and activities. For all of the technologies,

the chemistry of the reactor coolant is controlled by filtering, ion exchange, and chemical addition.

In an EPR reactor, core cooling and moderation are provided by light water (H20) at high pressure. There is no separate moderator system, only a

reactor coolant system. The coolant is circulated through 4 cooling loops, each containing a steam generator. A pressurizer and a chemical and

volume control system are used to maintain inventory and chemical composition in the reactor coolant system. The coolant used in this system

contains boron, which acts as a neutron absorber and can also result in a reaction that forms tritium in the heat transport system fluid.

Unique to the AP1000 reactor is the use of 2 cooling loops instead of 4, and therefore the use of only two steam generators. The remainder of the

system is similar to that of the EPR reactor.

In an ACR-1000 reactor, the heat transport system circulates light water through the reactor fuel channels to remove the heat produced by the

fission of uranium fuel within the fuel bundles. Coolant from the fuel channels passes to the four steam generators where the heat is transferred to

the secondary side to generate steam.

The ACR-1000 reactor has a calandria filled with a heavy water (D2O) moderator. The moderator slows down neutrons from fission reactions in

the fuel, increasing the opportunity for these neutrons to trigger additional fissions. The heavy water moderator is circulated and cooled. This

system is separate from the primary heat transport system, and is a low pressure, low temperature closed circuit. This activity includes routine

maintenance of the moderator systems and their auxiliaries.

Heavy water management is only applicable to the ACR-1000. Heavy water is managed during maintenance activities and those activities

connected to the movement of heavy water inventories into and out of the moderator system. Heavy water is managed in the ACR-1000 by the

D2O Supply System, the D2O Vapour Recovery System and the D2O Cleanup System.

Measures are taken to minimize the loss and downgrading of the heavy water, which escapes from the moderator systems. Heavy water may be

transported offsite to a licensed facility for the removal of tritium.

Losses from the heavy water management system are addressed under the active ventilation systems and radioactive liquid waste management

activities.




A-7


and Activities

Description

Operation of Active

Ventilation and

Radioactive Liquid

Waste Management

Systems

Radioactive Liquid Waste Management: The active drainage system segregates liquid waste by the degree of contamination and directs it to the

receiving tanks of the radioactive liquid waste management system. The system discharges treated wastes at a controlled rate to Lake Ontario after

stringent testing and treatment to maintain acceptable activity levels for release.

Tritium can be found in heavy water after contact with the reactor core, and this may be present in waterborne and airborne emissions from water

losses. There are cleanup (ion exchange columns and filters) and upgrading facilities for recovered heavy water that will be used if heavy water is

present in the liquid waste stream. There are also heavy water vapour recovery circuits in each reactor building to dry the atmosphere in areas that

are subject to heavy water leakage during operation or servicing of equipment.

Tritium can also be produced through neutron capture by B-10 in the EPR and AP1000 reactors. This tritium can be found in liquid and airborne

effluents due to water losses.

Radioactive Gaseous Waste Management: Gaseous wastes from potentially active areas, such as reactor buildings, will be monitored for

activity before release to the atmosphere. The gases from the active ventilation stacks are filtered through absolute and charcoal filters before

being released, to minimize the release of radioactivity. In some cases, the release of active gaseous waste is delayed to allow for decay of short-

lived radioisotopes.

Operation of Safety and

Related Systems

A multiple barrier approach has been built into the design of all of the reactors to control releases of radioactivity to the environment.

The ACR-1000 reactor has five safety systems: Shutdown System 1 (SDS1) and Shutdown System 2 (SDS2), which provide emergency safe

shutdown capability for the reactors, the Emergency Core Cooling System (ECCS), the Emergency Feedwater System (EFW) and the Containment

System.

The EPR reactor design includes four safety systems: the Safety Injection System (SIS) which provides emergency cooling, the Rod Cluster

Control Assembly (RCCA) shutdown system which provides rapid reactor shutdown, the Emergency Feedwater System (EFWS), as well as the

Containment System.

The AP1000 reactor includes four safety systems: the Passive Core Cooling System (PXS) which is designed to provide emergency core cooling;

the Passive Containment Cooling System (PCS) which provides for the removal of heat from the containment vessel using water and airflow; the

Containment System which is a steel vessel surrounded by a concrete shielding structure; and the Reactor Trip System, which acts to keep the

reactor operating away from any safety limit.

Fuel and Fuel Handling includes receipt, handling and storage of fresh fuel and used fuel.

Fuel: The reactor may be fuelled with low enriched uranium (LEU) or more highly enriched uranium, with a maximum enrichment of

approximately 5% U-235. The enrichment level and configuration of the fuel differs based on the reactor class. Fuel will be delivered to the NND

site in protective flame retardant containers and stored in these containers until required. Criticality safety is a concern due to the enrichment of the

fuel and a criticality program will be put in place to mitigate this.

Fuel Storage and Handling: The fuel handling system comprises equipment required for fuel changing, for the storage of fresh fuel, and for on-

site storage of used fuel.

Operation of Fuel and

Fuel Handling Systems

New fuel storage: New fuel is stored in a high density rack which includes integral neutron absorbing material to maintain the required degree of

subcriticality. The rack is designed to store fuel of the maximum design basis enrichment.




A-8


and Activities

Description

Fuelling system: In the ACR-1000 reactor, fuelling of the reactor is completed online. Fresh fuel bundles are pushed into one end of the fuel

channel by a remotely operated fuelling machine. Irradiated fuel bundles are simultaneously discharged at the other end of the channel into

another fuelling machine.

For the EPR and AP1000 reactors, fuelling must be completed during a refuelling outage. The refuelling operation is divided into four major

phases: preparation, reactor disassembly, fuel handling, and reactor assembly. Prior to refuelling, the reactor pressure vessel (RPV) cavity is

flooded with borated water and the reactor internals are placed in an internals storage pool separated from the reactor cavity by a removable gate.

Fuel assemblies are remotely removed from the RPV and sent to the Spent Fuel Pool (SFP) through the fuel transfer tube. Some new fuel

assemblies may be stored in the SFP, from where they will move through the fuel transfer tube and be placed into the RPV by the refuelling

machine. When the refuelling is complete, the RPV internals are replaced into the RPV, instrumentation, and control/shutdown rods are

reconnected, and the reactor vessel head is placed and fastened back onto the RPV. The borated water is then drained from the refuelling work

areas and can be reused in the IRWST.

Used Fuel Handling: In every reactor technology, the used fuel storage facility will be composed of transfer systems that carry the used fuel from

the reactor to a used fuel storage pool in which the fuel is stored and cooled. The used fuel will be stored in a used fuel storage bay until it has

cooled sufficiently for storage using an alternative means.

Used Fuel Bay and Auxiliaries: The design specifications and location of the used fuel storage pool will be determined based on the reactor

technology selected and the level of enrichment of the fuel to be used. Neutron absorbing material and spacers will be used to maintain the desired

degree of subcriticality. A fuel bay cooling and purification system is used to maintain chemical composition, volume, activity level and

temperature of the water in the fuel bay at desired levels. Filters, ion exchange columns and heat exchangers may be used depending on the

specific reactor design selected.

Turbine/Generator and Auxiliaries comprise the turbine/generator, steam supply, main condenser, feedwater heating system and auxiliary

systems. These systems are similar for the EPR, AP1000 and ACR-1000 reactors. This system also includes the generator oil supply and the

associated fire suppression systems. This activity also includes maintenance of the system components. Interactions with the environment resulting

from this activity are from oil leaks and water usage.

Turbine/Generator System: Each unit has one turbine/generator unit and its auxiliary systems. The EPR and ACR-1000 reactors have four

steam generators, and the AP1000 has two.

Steam Supply: Steam is produced in steam generators in the reactor building, and transported by pipes to each turbine/generator. The specific

configuration may vary by reactor design.

Main Condenser: Steam from the turbines exhausts into the condenser shells where it is condensed using Condenser Circulating Water and

collected in the hotwells. The condensate feedwater system collects the condensed steam from the turbine and supplies it to the steam generators.

External makeup to the closed loop steam and feedwater system is from the demineralized water storage tank. This configuration is independent of

reactor technology selected.

Operation of Secondary

Heat Transport System

and Turbine Generators

Feedwater Heating System: The feedwater heating system supplies feedwater to the steam generators where applicable, preheats the water to

achieve a good heat rate, and performs several other functions. This is generally true for all reactor technologies.




A-9


and Activities

Description

Auxiliary Systems: The major turbine/generator auxiliary systems are: the sampling system, which permits sampling steam and feedwater for

chemical analysis; and the chemical control system, which eliminates the residual oxygen from the deaerated feedwater and controls its pH. These

systems have different names depending on which reactor is being discussed but perform the same functions.

Operation of Condenser

and Condenser

Circulating Water,

Service Water and

Cooling Systems

The condenser circulating water system (CCW) supplies cold water to the condenser tubes to condense the steam from the turbine exhaust. Four

options are being assessed for the CCW system. These options are: once through cooling water, natural or mechanical draft cooling towers, or fan

assisted natural draft cooling towers. Dependent on climate and land considerations, a combination of these technologies may be used to provide

condenser circulating water at NND.

The once-through CCW system draws water from Lake Ontario, pumps the water through the condenser tubes, and discharges the water back to

Lake Ontario. Water will be brought into the plant through a lake bottom intake tunnel. The configuration of the intake tunnel and structure will be

similar to that currently being used at DNGS, but sized to the necessary water volumes.

Natural draft cooling towers are taller and have a smaller footprint than mechanical draft cooling towers, and up to two towers will be required for

each reactor unit. A natural draft tower uses convection and evaporation forces to cool the condenser circulating water.

Mechanical draft cooling towers use power driven fan motors to force or draw air through the tower. They are typically shorter and have a larger

footprint than natural draft cooling towers.

For both cooling tower technologies, makeup condenser cooling water is drawn from Lake Ontario at significantly lower rates than with once

through cooling, however, a portion of the water is lost to evaporation. The blowdown flow is directed to blowdown ponds, where mineral and

particulate impurities may be removed. Discharge will comply with appropriate criteria for surface water discharge to Lake Ontario.

Service Water Systems: Water will be drawn from Lake Ontario and distributed to the various systems. For the once-through cooling option,

service water will be combined with the CCW systems intake. For the cooling tower option, service water is drawn from the CCW closed loop

circuit.

Demineralized Water: NND will include two demineralized water plants to remove minerals removed from lake water prior to use in plant

cooling systems.

Inactive Drainage Systems: The inactive drainage system collects wastewater in various buildings (turbine building, waste treatment building,

pumphouses etc.). The wastewater is collected and treated as required to comply with discharge criteria prior to discharge.

Electrical Power Systems deliver power to and from the grid, generate emergency power and distribute power throughout the station. The

Electrical Power Systems will be similar for all reactor technologies as their operation is independent of the reactor itself. Possible environmental

interactions may include noise, spills or leaks from storage tanks, and air emissions from the generators.

Switchyard and Main Transformers: A switchyard is located near the station to connect the station to the grid transmission lines. The main

transformers and associated service transformers are oil cooled.

On-Site Power System: Power used internally at DNGS is supplied both from the unit itself and from the grid. Several buildings largely used for

administration or general support functions are supplied with electricity from the grid.

Operation of Electrical

Power Systems

Generation of Emergency and Standby Power: On-site standby diesel generators (DGs) provide back-up power sources to specific station

loads. The configuration of the diesel generators is similar for all reactor technologies.

Operation of Site Domestic Water: The domestic water system will be supplied from Durham Region water mains.




A-10


and Activities

Description

Sewage System: The sewage system collects waste throughout the complex and discharges it into the Regional Municipality of Durham sewage

mains.

Stormwater Management: Stormwater management features will be developed to address the requirements for runoff control. Stormwater runoff

ponds will be sufficient in number and size to provide adequate retention times following rainfall events. The pond design will incorporate an

emergency overflow bypass for flows in excess of the design storage capacity.

Compressed Air: The compressed air systems consist of instrument air, service air, high pressure air and breathing air.

Heating and Ventilation: The heating and ventilation systems are required to provide comfort to people working inside the plant and prevent

equipment and line freezing during plant shutdown in the winter. Steam, electricity, and hot water are used for heating.

On-Site Transportation: There is an extensive existing road network at the DN site including the roadways and parking lots necessary to service

DNGS. Further infrastructure will be developed to service NND. The roads are used by employees, contractors and visitors to drive to and from

the site, as well as for the transfer of materials.

Services and Utilities

Other Auxiliary Systems: Other auxiliary systems will include: communication systems; lighting systems, site security facilities, auxiliary and

service buildings, and fencing. NND will also have a dedicated onsite laundry facility.

Management of

Operational Low and

Intermediate-Level

Waste

Management of Low and Intermediate-Level Waste (L&ILW) will be similar regardless of reactor design selected. Two options for management

of L&ILW include storage in a modular building on the DN site, and transport to an appropriately licensed facility off-site. Low Level Storage

Buildings (LLSB), constructed as required, could accommodate both Low and Intermediate Level Waste. Eventually, the waste would be

transported to an appropriate facility off-site for long-term management. The first LLSB will be required by approximately 2017.

Transportation of

Operational Low and

Intermediate-Level

Waste to a Licensed Off-

site Facility

Transportation of L&ILW to the WWMF or another licensed facility and transportation of other radioactive materials, such as tritiated heavy

water, will be carried out in accordance with the NSCA and its Regulations and other applicable regulations (e.g., as made under the

Transportation of Dangerous Goods Act).

Dry Storage of Used Fuel Used fuel from NND will be stored in used fuel bays for approximately ten years following removal from the reactor. After this cooling period,

the fuel is moved to dry storage containers which are processed and stored in a Used Fuel Dry Storage (UFDS) Building. Storage containers differ

between the ACR and the two PWR reactors due to differences in fuel characteristics. UFDS buildings will be constructed as required, and will be

either an independent facility of an expansion to the existing DWMF.

Management of

Conventional Waste

The generation of non-radioactive wastes will be minimized to the extent practicable through re-use and recycling programs. All residual waste

will be collected regularly by licensed contractors and transferred to appropriately licensed off-site disposal facilities. Hazardous wastes will be

handled in accordance with applicable regulations.




A-11


and Activities

Description

Major Maintenance: Some systems and components will require maintenance, replacement or upgrading. A maintenance program for the plant

will be developed to address issues related to ageing, wear and degradation. A portion of this work will require the unit to be offline for these

maintenance activities to be completed. Typically, this work is done during a maintenance or refuelling outage that occurs once every one to three

years (1-2 months duration), depending on station protocols and an assessment of needs. The periodic chemical cleaning of systems and

components (e.g. steam generators) is also included in this activity. Many maintenance activities do not require a unit shutdown, and will be

performed with the unit in an operating state.

Refurbishment: During the 60 year life of the station, specific reactor components and the steam generators, will likely require replacement. In

addition to the steam generators, refurbishment of the ACR-1000 would require replacement of fuel channel assemblies, calandria tubes and

feeder pipes; and the EPR and AP1000 would require replacement of the reactor pressure vessel head. Each of these activities will require the

reactors being removed from service for a period of time (one to three years).

The reactor will be defuelled, systems will be drained and access ways through containment created. The components will be removed by cutting

or disconnecting piping and equipment.

The Low and Intermediate Level Waste from refurbishment will be transported either to a purpose built facility on-site or transported a licensed

facility is in accordance with CNSC transportation regulations in place at the time of refurbishment.

Replacement /

Maintenance of Major

Components and Systems

Safe Storage: Preparation for, and safe storage of a reactor are the first two of the three-stage decommissioning program (the final stage is

dismantling, disposal and site restoration). Safe storage involves removing the reactors from service for a period of time to allow for decay of

radionuclides. In preparation for safe storage, the reactors will be defueled, and dewatered. During the safe storage period resident maintenance

staff will perform routine inspections and carry out preventative and corrective maintenance.

Physical Presence of the

Station

When complete, NND will exist as a functioning nuclear power plant comprised of up to four individual reactors. The greatest potential difference,

in an environmental context, between the new facility and the existing station are the cooling towers that may be included as an alternative to the

once-through cooling. From a physical presence perspective, natural draft cooling towers would be the more dominant of the cooling tower

options, with several towers likely, each extending to a height of as much as 152.4 m above finished grade. A visible steam plume would routinely

be associated with cooling tower operation.

During operations, used reactor fuel will be stored onsite in water-filled bays for a period of several years, following which it will be removed

from the bays, repackaged into dry storage containers and placed into on-land storage, also onsite, for a period of up to several decades.

Administration,

Purchasing and Payroll

Upon completion of the Construction Phase of the project, the maximum estimated staff required for the operation of NND is expected to be 1,400

for the first two units in approximately 2016, and 2,800 for four units in about 2025. During the period 2018-2024, the workforce involved in the

operation of units 1 and 2 will overlap with the workforce staff associated with the construction of units 3 and 4. During these years the Project-

related workforce will total approximately 5,200.

The Project-related workforce will increase from the normal complement of 2,800 by a further 2,000 during NND refurbishment (approximately

2050-2055).




APPENDIX B

COMPENSATION DEVELOPMENT OPTIONS TABLE




B-1

Appendix B: Compensation Development Options Table

Compensation

OptionAdvantages Limitations

Species/

Community

Affected

Benefits to

Local Area

Technical

Feasibility

Compensation

AreaConclusion Rank

Site Study Area

Modification of

infill front and

enhancement of

habitat in the infill

area reduces the

overall footprint.

Will provide near

shore habitat for

Round Goby

community.

Round Goby Would require

additional fill

material, including

a source of round

cobble.

Project occurs in the

SSA but with limited

benefit to diversifying

quality of habitat.

Potential for benefiting

non target and/or

undesirable fish

species. Potential for

increased benefit to

target species in future

years if Round Goby

populations decline.

Consultation with

coastal engineer

required since infill

could affect

currents and

sediment transport.

Modification of

Lake Infill

Design

Enhancement of

near shore habitat

function around the

DN site, if

moderate and

optimally located,

would not result in

a significant

increase in I&E.

Possible increase in

I&E from fish

attracted to the

area.

Warm and cold

water species

Create

additional

complex near

shore habitat

providing a

forage/spawnin

g area for

native species.

Redesign of infill

area would be

required. Design

needs to consider

navigational

constraints.

Would provide a

component of the

compensation plan

but would likely

need to be

combined with

other initiatives.

Overall benefits could

be high since this

option will limit the

infill area and benefit

the SSA.

Modifications would

need to be limited for

habitat compensation

to ensure that I&E

losses would not

substantially increase.

Pass




B-2

Appendix B: Compensation Development Options Table (Cont’d)

Compensation


Species/

Community

Affected

Benefits to

Local Area

Technical

Feasibility

Compensation

AreaConclusion Rank

Site Study Area

Compensation can

be in the SSA

and/or LSA. If

compensation is in

the SSA then on-

going management

would be included

under site

biodiversity plan.

Recent 2009

studies indicate

round goby are the

most common

species in the

nearshore and

additional habitat

creation is likely to

favour this species.

Round Goby are

currently the most

prevalent and most

likely to benefit.

Requires

substantially more

fill materials to

provide gentle

slope.

Option to identify

local areas.

Will require source

of round cobble

sufficient for the

area.

Regenerate historic

shoals along Lake

Ontario north shore

area.

Providing

additional onshore

habitat in the SSA

may increase fish

populations in area,

and result in an

increase in I&E.

Under existing

conditions, will

provide habitat for

Round Goby and could

result in an increase in

I&E if compensation is

within the SSA.

However, if Lake

Whitefish stocks

recover, the possibility

exists to increase

habitat for this species

and other salmonids.

Will require

consultation with

coastal engineer to

assess effects on

currents and

sediment transport.

On-shore &

off-shore

shoals*

Compensation in

the LSA could

create additional

habitat without

resulting in

increased I&E.

Success of on-

shore shoals is

unknown.

Salmonid and

forage species may

use habitat in the

longer term if goby

numbers are

reduced in the

future. Goby will

likely feed on

whitefish and other

salmonid species

eggs and larvae.

Enhanced

habitat is

within the local

municipality of

Clarington

Creation of suitable

slopes needs to

consider

navigational needs.

Can provide a

potential

component of

compensation plan,

and large areas can

be considered.

Overall benefits will

be moderate under

existing conditions but

could be of greater

significance in the

future if goby stocks

decline and Lake

Whitefish populations

recover.

Pass




B-3


Compensation


Species/

Community

Affected

Benefits to

Local Area

Technical

Feasibility Compensation Area Conclusion Rank

Local Study Area

Compensation is

focused in Local

Study Area (LSA)*.

Watercourse restoration

is small in scale and

would need to consider

a number of projects.

Watercourse

enhancements

would benefit

salmonids and

cyprinids,

including

undesirable

species such as

carp

Enhanced

habitat is

within the local

municipality of

Clarington.

Requires

knowledge of

hydrology and

research into

projects that will

function as

intended but is

technically feasible

in most areas.

Restoration could

provide a substantial

component of the

compensation plan

depending on the

specific initiative

since the quality of

habitat created could

be high.

Quality vs quantity

of habitat needs to

be defined since this

option has the

potential to create

high quality habitat

but not sufficient

quantity to offset

loss.

Coastal wetlands can

be highly productive

areas and the quality

of the habitat created

can be of greater value

than some nearshore

compensation efforts

that create less

valuable habitat.

Coastal wetland

restoration in these

areas has historically

been unsuccessful since

it is dependent on the

condition of the

watercourse.

Requires further

discussion with

CLOCA to identify

local areas that

would be feasible

for enhancements.

This option has high

potential benefits

since compensation

would occur within

the LSA and

Clarington RM and

projects would be

high profile

however quantity

of compensation

would be low.

Restoration –

CLOCA

fisheries

management

plan. Farewell,

Black, Soper,

coastal

wetlands,

barrier

removal/

modification

Effective means to

restore fish

communities to

reaches with

previously restricted

access and improve

water quality and in-

stream habitat

conditions.

Focus of program is

on salmonids but

forage base is likely to

benefit as well.

Carp are prevalent

species and would need

to be controlled.

Removal/modification

of barriers in lower

watershed areas could

allow aquatic invasive

species (e.g. Round

Goby/Sea Lamprey)

access to upstream

reaches.

Coastal wetland

enhancements

would benefit

the local fish

community and

forage base.

Can be "high

profile" project

with anglers,

naturalist and

other

stakeholder

groups

Will require

partnering with

CLOCA to allocate

compensation

funds

Quantity of habitat

replaced will not

offset proposed loss.

Would need to be

combined with other

initiatives.

Need to consider

potential for

invasive species to

access watersheds.

Pass




B-4


Compensation


Species/

Community

Affected

Benefits to

Local Area

Technical


Local Study Area

Requires

substantially more

fill materials to

provide gentle

slope.

Will require

source of round

cobble sufficient

for the area.

Compensation can be

in the SSA and/or

LSA. If compensation

is in the SSA then on-

going management

would be included

under site biodiversity

plan.

Regenerate historic

shoals along Lake

Ontario north shore

area.

Recent 2009 studies

indicate round goby are

the most common

species in the nearshore

and additional habitat

creation is likely to

favour this species.

Providing additional

onshore habitat in the

SSA may increase fish

populations in area, and

result in an increase in

I&E.

Option to

identify local

areas.

Under existing

conditions, will

provide habitat

for Round Goby

and could result

in an increase in

I&E if

compensation is

within the SSA.

However, if Lake

Whitefish stocks

recover, the

possibility exists

to increase

habitat for this

species and other

salmonids.

Will require

consultation with

coastal engineer to

assess effects on

currents and

sediment transport.

Compensation in the

LSA could create

additional habitat

without resulting in

increased I&E.

Success of on-shore

shoals is unknown.

Round Goby are

currently the

most prevalent

and most likely

to benefit.

Salmonid and

forage species

may use habitat

in the longer

term if goby

numbers are

reduced in the

future. Goby

will likely feed

on whitefish and

other salmonid

species eggs and

larvae.

On-shore &

off-shore

shoals*

Enhanced

habitat is

within the local

municipality of

Clarington

Creation of suitable

slopes needs to

consider

navigational needs.

Can provide a

potential component

of compensation

plan, and large areas

can be considered.

Overall benefits

will be moderate

under existing

conditions but

could be of

greater

significance in

the future if goby

stocks decline

and Lake

Whitefish

populations

recover.

Pass




B-5


Compensation


Species/

Community

Affected

Benefits to

Local Area

Technical


Regional Study Area

Diversifying

Forage Base

through

Replacement of

Stock

Diversifying forage

base would have local

and lake wide benefits

and would also meet

the objectives of the

Lake Ontario

Management Unit

(LOMU).

Deepwater Cisco

rearing in hatchery only

experimental, project

ongoing in N.Y (Lake

Ontario).

Meets LOMU

objectives

Will require

partnering with

MNR and possibly

N.Y. State

Option would

replace fish I&E

losses from intake

and also compensate

for habitat loss.

High profile

project with lake

wide and local

benefits but

difficult to

observe tangible

improvement.

Deepwater

Cisco species,

Lake Herring,

Round Whitefish

Would fortify efforts

focused on stream

rehabilitation to

enhance salmonid

rehabilitation.

Forage base stocking

does not directly

compensate for habitat

loss.

Fortifies stream

rehabilitation

efforts.

Expertise is

available at

White’s Lake

hatchery

Would need further

discussion with

MNR/DFO

Requires further

discussion with

MNR/DFO.

Would help re-

establish the native

forage base and would

aid in moving away

from dependence on

introduced species

such as Alewife

Hatchery should not

occur within SSA since

may result in increased

I&E (e.g. Port

Washington example in

Lake Michigan)

Could be “high

profile”

especially with

anglers,

naturalists and

other

stakeholder

groups

Potential high costs

for development

and operation.

Could be offset if

can use MNR

hatcheries.

Potential for

high benefits

from this option

since it meets the

LOMU objective

and effects would

extend to

Clarington area.

Potential to

collaborate with MNR

(provincial hatcheries)

or develop a hatchery

within LSA.

Deepwater Cisco

rearing is currently

experimental.

Would provide

potential

compensation under

Section 32 of FA, if

required.

Deepwater

Cisco (

important food

base for Lake

Ontario top

predators )

Pass




B-6


Compensation


Species/

Community

Affected

Benefits to

Local Area

Technical


Regional Study Area

Lake Ontario

Areas of

Concern

Hamilton

Harbour (AOC)

Modification of

Hamilton Harbour

(HH) embayment

would equate to large

area of compensation

Warm and cold

water species

HH AOC has been

extensively

monitored and

restoration plans

developed. In need

of corporate

partners to fund

projects.

Potential for large

area

Potential for

large project

partnering that

could have lake

wide benefits but

projects will not

occur in local

area

Possibility to partner

in multi corporation

project for greater

benefits through

habitat creations and

rehabilitation

Indirectly –

forage base

dependent fish

(salmonids)

Would need

confirmation that

lake herring move

into this area of the

lake.

The Fish and

Wildlife Habitat

Restoration Project

in Hamilton Harbour

and Cootes Paradise

proposes to create

372 ha of fish habitat

Overall benefit is

low since site is

far removed from

the SSA and

LSA, and

benefits may not

be significant

relative to other

contributors to

program.

Would need water

quality issues to be

addressed.

Restore historic

whitefish and herring

spawning area

Would benefit entire

Lake Ontario fish

community through

restoration f forage

base.

Hamilton Harbour far

removed from SSA and

LSA.

Modifications

to HH would

aid in

diversifying

entire lake

forage base and

therefore

would benefit

local fish

communities

Pass

Site Study Area (SSA) - The SSA corresponds to the existing DNGS property and approximately 2-3 km into Lake Ontario. The SSA is the area where direct

effects on aquatic habitat and biota are most likely (such as the proposed infill area, offshore intake and diffuser)

Local Study Area (LSA) - The LSA refers to lands and portions of Lake Ontario outside the LSA but within Clarington Area.

* Indicates an option that has been considered at more than one study area scale.