ST. LAWRENCE SEAWAY

STUDY

Final Report

Fall 2007

GREAT LAKES

By:

Transport Canada

U.S. Army Corps of Engineers

U.S. Department of Transportation

The St. Lawrence Seaway Management Corporation

Saint Lawrence Seaway Development Corporation

Environment Canada

U.S. Fish and Wildlife Service

ST. LAWRENCE SEAWAY

STUDY

GREAT LAKES
Publication

This publication is also available in French under the title:

Étude des Grands Lacs et de la Voie maritime du Saint-Laurent. Rapport final, automne 2007.

Permission is granted by the Department of Transport, Canada, and the U.S. Department of Transportation, to copy

and/or reproduce the contents of this publication in whole or in part provided that full acknowledgement is given to

the Department of Transport, Canada, and the U.S. Department of Transportation, and that the material be

accurately reproduced. While the use of this material has been authorized, the Department of Transport, Canada, and

the U.S. Department of Transportation, shall not be responsible for the manner in which the information is

presented, nor for any interpretation thereof.

The information in this publication is to be considered solely as a guide and should not be quoted as or considered to

be a legal authority. It may become obsolete in whole or in part at any time without notice.

Publication design and layout by ACR Communications Inc.

ii Great Lakes St. Lawrence Seaway Study
FOREWORD AND ACKNOWLEDGEMENTS

We are pleased to present the binational report on the Great Lakes St. Lawrence Seaway Study, the result of

collaborative research and analysis by seven federal departments and agencies from Canada and the United States.

The report summarizes the findings of the study and sets out observations and key considerations for continuing the

success of a productive, safe and reliable waterway in a cost-effective, efficient and sustainable manner.

The Great Lakes St. Lawrence Seaway system is a vital resource. As one of the world’s greatest and most strategic

waterways, it is also an essential part of North America’s transportation infrastructure. The system enables and

facilitates significant domestic and international trade for the continent’s largest interior markets including the

industrial, manufacturing, agricultural and natural resource sectors. 

It is likely that few outside the Great Lakes basin and St. Lawrence River region appreciate the crucial role of the

waterway. This resource flows directly across two provinces and eight states, situated at the axis of the world’s largest

binational trading relationship. Since coming into full operation in 1959, the St. Lawrence Seaway has handled more

than 2.3 billion metric tons of cargo with an estimated value of $350 billion. The competitiveness, prosperity and

economic progress achieved are the result of a strong partnership that provides enormous benefit to both countries. 

The upcoming 50th anniversary of the opening of the St. Lawrence Seaway is a reminder that the economic vitality and

efficiency of marine transportation and trade cannot be taken for granted. Waterborne movement is cost competi tive,

fuel efficient, safe, and possesses some environmental advantages. When integrated with rail and trucking into a

multimodal transportation network, it can greatly increase capacity with minimal negative impacts on society.

For the Great Lakes St. Lawrence Seaway system to be sustainable and optimize its contribution to the future

movement of goods, it needs a strategy for addressing its aging infrastructure. Principally this includes its lock systems,

but it should also adopt a more holistic view of the ports it serves and their evolving linkages to other modes of

transportation. Recognition of this central fact by both nations prompted this comprehensive study on future needs 

of the system focusing on strategic issues that encompass economic, environmental and engineering dimensions. 

Study partners look to a future in which a modern waterway capitalizes on its inherent advantages to meet the 

projected doubling of freight traffic and trade activity in North America. An improved Great Lakes St. Lawrence

Seaway system — one that is part of a more integrated transportation network and trade corridor — can serve as a

complement and alternative that can accommodate rapidly growing containerized freight traffic as easily as it does

bulk and general cargoes. 

This binational report is a unique document. It expresses not only a common determination, but also a climate of

mutual understanding, sharing and confidence among the study partners. This is a testament to the scores of

individuals representing the seven participating departments and agencies who devoted their considerable time, 

effort and expertise to this initiative. 

Thanking all who have contributed to this undertaking would be a significant task in itself and inevitably result in

omission of individuals who merit deep gratitude. However, we cannot forgo honouring the study’s management

committee: Marc Fortin from Transport Canada and David Wright from the U.S. Army Corps of Engineers. 

Their commitment and determination built a culture of teamwork that has resulted in this impressive effort.

Great Lakes St. Lawrence Seaway Study iii
The Great Lakes St. Lawrence Seaway system is bigger than any report, or commission, charged to investigate it. 

It belongs to all stakeholders. It is our hope that the study will have a significant influence in creating a context for

discussion and action to develop a safe, healthy and economically sound waterway for future generations. In our 

estimation, the study lives up to its appointed task of providing a comprehensive understanding of needs, opportunities

and challenges in the next 50 years.

We look forward to sharing and discussing the work and findings of the study. 

Respectfully,

The Great Lakes St. Lawrence Seaway Study’s Steering Committee 

Kristine Burr Jeffrey N. Shane

Assistant Deputy Minister, Policy Under Secretary for Policy

Transport Canada U.S. Department of Transportation

Steering Committee Co-Chair Steering Committee Co-Chair

Theodore A. Brown

Acting Chief, Planning and Policy

U.S. Army Corps of Engineers

Richard J. Corfe

President and Chief Executive Officer

The St. Lawrence Seaway Management Corporation

Collister Johnson, Jr.

Administrator

Saint Lawrence Seaway Development Corporation

Albin Tremblay

Regional Director General

Environment Canada

Charles M. Wooley

Deputy Regional Director

U.S. Fish and Wildlife Service

iv Great Lakes St. Lawrence Seaway Study
Foreword and Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii

Executive Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Chapter 1 – Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Chapter 2 – The Waterway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

System overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Origins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

The system today . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

The Great Lakes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

The Welland Canal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

The Montreal-Lake Ontario section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

The St. Lawrence ship channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

System operation and management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Evolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Chapter 3 – The Economic Importance of the GLSLS. . . . . . . . . . . . . . . . . . . . . . . . . . 35

Evaluating significance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Cargoes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Grain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Inputs to the iron and steel industries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Coal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Stone. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Other cargoes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Containerized cargo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

System segments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Other determinants of traffic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Forecast based on existing traffic mix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

The competitiveness of the GLSLS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Chapter 4 – Environmental Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Valued ecosystem components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Air quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Terrestrial ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Aquatic ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Evaluation of stressors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Issues related to channel and port maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Water management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Land-based support activities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Ship operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Ice breaking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Great Lakes St. Lawrence Seaway Study v

TABLE OF CONTENTS
Cumulative effects analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Future trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Managing the environmental impacts of navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Assessment systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Current environmental management actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Measures to control the effects of ballast water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Ongoing monitoring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Chapter 5 – Maintaining the Infrastructure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

System infrastructure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

The locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Bridges, roads and tunnels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Navigation channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Infrastructure stressors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Current condition of the infrastructure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Operations and maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Forecasting maintenance requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Physical infrastructure maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Navigation channel maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Optimizing maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Informing future maintenance strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Cost estimates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Chapter 6 – Opportunities and Challenges. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

The global context . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Global trends in containerization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Regional trends. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

The challenge of congestion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Shortsea shipping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Impact on the GLSLS transportation network. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Emerging opportunities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Containers and the GLSLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

New service deployment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Determinants of new waterborne services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Shipper preferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

New vessel technologies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

New cargo and new vessel forecasts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Chapter 7 – Policy and Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Framing the future of the GLSLS system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Role in North American transportation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Solutions for a dynamic future. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

Optimizing the existing infrastructure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

Environmental sustainability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Monitoring future progress and success. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Chapter 8 – Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

vi Great Lakes St. Lawrence Seaway Study
Chapter 2

Figure 2.1 The GLSLS system within North America. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Figure 2.2 Key features of the GLSLS system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 2.3 Major highways and railways within the GLSLS region. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 2.4 Schematic of the profile of the GLSLS in steps from Lake Superior to the Atlantic Ocean . . . 21

Figure 2.5 Vessels of the Great Lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Figure 2.6 Profile of the Welland Canal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Figure 2.7 MLO locks profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Chapter 3

Figure 3.1 Main industrial centres of the GLSLS system’s region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 3.2 Grain trade patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure 3.3 Iron ore trade patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Figure 3.4 Iron and steel trade patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Figure 3.5 Coal trade patterns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Figure 3.6 Stone trade patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Figure 3.7 Average annual tonnage shipped 1995-2003 (millions of metric tons) . . . . . . . . . . . . . . . . . . . . 44

Figure 3.8 Average annual tonnage shipped 1995-2003 (millions of metric tons) . . . . . . . . . . . . . . . . . . . . 44

Figure 3.9 Traffic forecast for the Montreal – Lake Ontario section to 2050 . . . . . . . . . . . . . . . . . . . . . . . . 48

Figure 3.10 Traffic forecast for the Welland Canal to 2050. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Figure 3.11 Traffic forecast for the Soo Locks to 2050. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Figure 3.12 Forecast by commodity for Montreal – Lake Ontario section to 2050 (most likely scenario) . . 49

Figure 3.13 Forecast by commodity for Welland Canal to 2050 (most likely scenario) . . . . . . . . . . . . . . . . . 49

Figure 3.14 Forecast by commodity for Soo Locks to 2050 (most likely scenario) . . . . . . . . . . . . . . . . . . . . . 49

Figure 3.15 Estimated costs of unscheduled lock closure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Chapter 5

Figure 5.1 How navigation locks operate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Figure 5.2 Likelihood of failure if investments are made in maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Figure 5.3 Likelihood of failure if no investment is made in maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Figure 5.4 SLSMC – Montreal-Lake Ontario (MLO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Figure 5.5 SLSMC – Welland Canal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Figure 5.6 SLSDC – Montreal-Lake Ontario (MLO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Figure 5.7 Soo Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Figure 5.8 Scheduled costs under the reliable system scenario versus expected unscheduled 

repair costs and transportation costs from under funding the priority components. . . . . . . . . . . 93

Chapter 6

Figure 6.1 Projected growth in gross domestic product of the GLSLS region. . . . . . . . . . . . . . . . . . . . . . . . 96

Figure 6.2 Projections of world container traffic compared to that of North America. . . . . . . . . . . . . . . . . 97

Figure 6.3 Evolving patterns of trade between Asia and North America . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Figure 6.4 Forecast of market for container traffic carried by all modes in the GLSLS binational region. . 100

Figure 6.5 GLSLS vessel routes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Figure 6.6 Present and projected share of container traffic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Great Lakes St. Lawrence Seaway Study vii

LIST OF FIGURES
Chapter 2

Table 2.1 Lake characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Chapter 3

Table 3.1 Transportation savings offered by the GLSLS by commodity. . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Table 3.2 Transportation savings offered by the GLSLS by region. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Chapter 4

Table 4.1 Valued ecosystem components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Table 4.2 Environmental stressors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Table 4.3 Stressor analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Chapter 5

Table 5.1 Summary of criticality assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Chapter 6

Table 6.1 Performance characteristics of potential new vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

viii Great Lakes St. Lawrence Seaway Study

LIST OF TABLES
Geography has provided a natural highway reaching into

the heart of North America. As a result, the waters of the

St. Lawrence River and the Great Lakes were used from

earliest times to open up the region to commerce and

settlement. Eventually, the areas around the waterway

evolved into the continent’s industrial heartland.

Not surprisingly, human action sought to enhance what

nature provided. Soon after European settlers arrived, the

first efforts were made to bypass rapids, install locks and

deepen channels. This work persisted for almost 200 years

and culminated in the mid twentieth century with the

completion of a waterway that could take ocean-going

vessels through the St. Lawrence, around Niagara Falls

and across the upper Great Lakes to the furthest shores of

Lake Superior – a distance of some 3,700 kilometres or

2,300 miles.

That was more than half a century ago. With the passage of time, the original economic factors that drove the

creation of the Great Lakes St. Lawrence Seaway (GLSLS) system underwent significant change. Moreover, the

infrastructure itself began to show the inevitable effects of wear and aging. 

THE GLSLS STUDY

The beginning of the new millennium marked an appropriate moment to reflect on the system, its future prospects

and what should be invested to keep it operational. As joint custodians of the GLSLS and its infrastructure, the

governments of Canada and the United States (U.S.) entered into a Memorandum of Cooperation that formed the

framework for a binational effort to address the fundamental question: 

What is the current condition of the GLSLS system, and how best should we use and maintain the system, in its current

physical configuration, in order to capitalize on the opportunities and face the challenges that will present themselves in

coming years?

Seven Canadian and U.S. federal departments and agencies were involved in a multi-year study of this issue:

Transport Canada, the U.S. Department of Transportation, the U.S. Army Corps of Engineers, the Canadian 

St. Lawrence Seaway Management Corporation, the U.S. Saint Lawrence Seaway Development Corporation,

Environment Canada and the U.S. Fish and Wildlife Service. Their representatives formed a steering committee

responsible for the Study’s overall strategic direction. Study tasks and analysis were overseen by a management

committee consisting of one representative from Transport Canada and one from the U.S. Army Corps of Engineers. 

The Study itself was carried out by subject-matter experts organized into three working groups. The Economic

Working Group was tasked with investigating the current and possible future role of the GLSLS in both regional 

and global commercial and transportation networks. The Environmental Working Group examined the impact of

navigation and its operations within the larger context of ecological conditions in the Great Lakes basin and 

St. Lawrence River. Finally, the Engineering Working Group examined the current physical condition of lock system

infrastructure, evaluated its reliability and developed options for its future maintenance. 

Great Lakes St. Lawrence Seaway Study 1

EXECUTIVE SUMMARY
THE IMPORTANCE

OF THE SYSTEM

The three working groups began with a

common recognition of the importance

of the GLSLS system. It is located at the

core of North America’s industrial

heartland, which contains a quarter of

North America’s population, and

accounts for 55 percent of its manu -

facturing and service industries. Within

this region, the waterway plays a key

strategic role, carrying the iron ore and

coal that are critical to the health of

vital industries such as steelmaking and

automotive manufacturing. 

Physically, the GLSLS consists of an

interconnected system of locks located

at 16 different sites, four major navigational channels, more than 50 ports, several bridges, tunnels and a variety of

approach roads. Within this array there are four distinct segments. The Great Lakes waterway links Lakes Superior,

Michigan, Huron and Erie through locks at Sault Ste. Marie and the channels of the St. Marys, Detroit and St. Clair

rivers. Key to this segment are the two operational U.S. locks, the Poe and MacArthur locks. The second segment is

the Welland Canal, which consists of eight Canadian locks linking Lake Erie to Lake Ontario. The third part of the

system is known as the Montreal-Lake Ontario segment, which includes seven locks: the Iroquois, Upper and 

Lower Beauharnois, Côte Ste. Catherine and St. Lambert locks on the Canadian side of the waterway, and the

Dwight D. Eisenhower and Bertrand H. Snell locks on the American side. Finally, there is the St. Lawrence ship

channel, which has no locks and runs downstream from the port of Montreal to the Atlantic Ocean.

ECONOMIC ROLE

When this system was completed with the opening of

the St. Lawrence Seaway in 1959, planners envisaged

that it would carry grain from North America’s prairies

to the markets of Europe and the Soviet Union.

Subsequent political and economic changes in those

markets have reduced demand for North American

grain, which has recently found alternative buyers in

the Pacific region. While grain still moves through the

GLSLS, its volumes have been overshadowed by huge

shipments of iron ore, which are carried from

Minnesota and Wisconsin to the smelters of Ohio.

Today, the waterway transports more than 80 percent of

the iron ore used in U.S. steel production. The system

also carries vast quantities of coal from Montana and

Wyoming to power generating stations along the shores

of the Great Lakes. Other commodities shipped through

the system include limestone, coke, salt, petroleum

products, chemicals, processed iron and steel as well as

a variety of goods carried in containers. 

Thunder Bay

Green Bay

Milwaukee

Chicago

Detroit

Hamilton

Toronto

Prescott

Valleyfield

Montreal

Trois-Rivieres

Quebec

Sept Iles

St. Lawrence

Lake Ontario

Lake Erie

Lake Huron

Lake Michigan

Lake Superior

Toledo

Burns

Harbour

LOCKS

1 St. Lambert

2 Cote Ste. Catherine

3 Lower Beauharnois

4 Upper Beauharnois

5 Snell

6 Eisenhower

7 Iroquois

8 Welland Canal (8 locks)

9 Soo Locks

PORTS

CANADIAN LOCKS

UNITED STATES LOCKS

Windsor

Cleveland

Erie

Buffalo

Oswego

Ogdensburg

Becancour

Oshawa

Duluth/

Superior

79

76

69

37

35

0 20 40 60 80

Internal Great Lakes

(no locks)

Lower St. Lawrence River

(no locks)

Soo Locks

Welland Canal

Montreal-Lake Ontario

0 50 100 150 200 250 300 

Iron Ore 

Coal 

Grain 

Steel 

Stone 

All Other 

Total 

103 

37 

17 

8 

51 

45

261 

Average annual tonnage shipped 1995-2003 

(millions of metric tons)

Average annual tonnage shipped 1995-2003 

(millions of metric tons)

Executive Summary

2 Great Lakes St. Lawrence Seaway Study
Between 1995 and 2003, total cargo traffic through the GLSLS averaged 261 million metric tons (Mt) annually. 

Of this, some 69 Mt passed through the Soo Locks, while the Welland Canal and Montreal-Lake Ontario locks saw

about 37 Mt and 35 Mt, respectively. The balance moved between ports within the system without passing through

any of its locks. Economic forecasts suggest that this traffic is likely to grow at a moderate pace over the coming half

century. This expectation leads to the fundamental question of what role the GLSLS is likely to play in the future:

the answer will determine how much should be invested in keeping it operational. 

ENVIRONMENTAL IMPACTS

The economic advantages of the GLSLS have to be balanced against its costs. Those costs entail more than just the

expenditures associated with operating, maintaining or repairing its infrastructure, or the costs incurred by the

transportation industry in the event of unexpected component failures. There are also the impacts associated with

commercial navigation to the ecology of the Great Lakes basin and St. Lawrence River.

The ecosystem of the GLSLS is vulnerable to a

variety of stressors. Residential settlement, urban

growth, industrial activities, tourism and recre -

ation have all had an impact on environmental

degradation. Thus navigation is by no means the

only factor operating on the region’s environment.

When the system was originally completed,

environmental protection was not a high public

priority and environmental impacts were poorly

understood. Over time, however, it became clear

that the construction, operation and mainten ance

of the GLSLS had a number of significant effects

on the ecology of the basin. 

Ships’ wakes eroded shorelines. The management

of water levels in the basin altered local ecologies,

drying out some areas and inundating others.

Dredging of navigational channels caused turbidity

in the water while posing the challenge of how 

to dispose of dredged material with a minimal

impact on the environment. Ship engines burned

a lower grade fuel that contributed to air

pollution. Vessels were also coated with special

corrosion-resistant paint that released toxins 

into the water.

Many of these effects were part of larger

environmental impacts caused by industrial,

commercial and residential development in the

region. Some, however, were unique to navigation

through the system. Perhaps the most important

of these was the introduction and transmission of

aquatic non-indigenous invasive species (NIS) via

the ballast water of vessels. Examples of such

species include the zebra mussel. With few 

natural predators in the region, such species

proliferate rapidly with significant negative effects

on native ecology. 

Great Lakes St. Lawrence Seaway Study 3

Executive Summary

Environmental stressors 

Class of stressor Stressor 

Global Climate change

Water withdrawal & diversions

Introduction & transfer of aquatic NIS

Air emissions

Industrial/municipal effluent

Solid waste disposal

Landscape fragmentation

Runoff

Shoreline alteration/hardening

Noise & vibration

Erosion and sedimentation

Introduction & transfer of aquatic NIS

Shoreline alteration/hardening

Waste disposal/pollution

Erosion and sediment re-suspension

Wildlife conflicts

Channel modification

Dredge material placement

Shoreline alteration/hardening

Maintenance dredging

Water management for all purposes

Infrastructure development

Facility maintenance

Uncontrolled releases

Introduction & transfer of aquatic NIS

Ship’s air emissions

Biocides (antifouling)

Accidents/spills

Noise & vibration

Waste disposal

Prop wash, surge and wake

Cargo sweeping

Groundings/anchoring

Wildlife encounters

Ice breaking

Non-navigational related Navigational related 

Development 

and land use 

Water-based 

recreation and 

tourism 

Channel & port

maintenance 

Water management

Land-based support

activities 

Ship operations 
Recognition of these impacts within the broader context of a greater

appreciation of the environment, has led to a general commitment to

remediation. As a result, ships’ speeds are controlled to reduce wakes in narrow

channels. Toxic paints have been phased out. To reduce air pollution, vessel

operators are exploring fuel alternatives and scrubbing technologies. Finally,

strict controls have been introduced on ballast water. Vessels are now required

to manage ballast water by exchanging at sea in order to reduce the risk of any

further NIS introductions. Even loaded vessels that carry only small quantities

of residual ballast are required to properly manage their residual ballast if it is to

be mixed with Great Lakes waters and subsequently discharged into the lakes. 

Activities such as ongoing maintenance of infrastructure or dredging and the

placement of dredged material will continue to affect the region’s environment,

but their impact can be minimized through effective application of environ -

mental assessments, remedial actions, sound environmental management

strategies and best practices.

Generally, it seems that organizational and governance frameworks together with accompanying policies and

legislation are likely adequate for the management and control of the navigation-related activities that have had a

negative impact on the environment in the region. However, because most of the environmental stressors in the

Great Lakes basin and St. Lawrence River are not related to navigation, action on navigational stressors may be

beneficial but, on its own, is unlikely to result in significant gains to overall environmental quality.

THE FUTURE OF THE GLSLS

It is clear that the GLSLS offers shippers significant savings: surveys suggest that the system saves them

approximately $2.7 billion a year in transportation costs. Moreover these savings are especially felt in strategic sectors

such as steelmaking and energy, the competitiveness of which is vital to the health of the North American economy. 

The GLSLS also offers shippers considerable spare capacity. This is becoming increasingly significant as highways and

rail lines in the region experience growing congestion. Much of the huge volumes of trade passing between Canada

and the U.S. is funnelled through crossings at Windsor-Detroit and Niagara Falls. The road and rail networks carrying

this traffic are reaching physical limits, the challenges of which have been exacerbated by new security procedures. 

The GLSLS can play an important role in relieving some of these pressures by offering complementary transportation

routes through less busy ports and by moving

goods directly across lakes rather than around

them. Called shortsea shipping, the latter

alternative would require an investment in

upgraded surface links to the rest of the

transportation grid, enhanced port facilities

for loading and unloading containers as well

as regular shipping service along the likeliest

alternative routes.

The future of the waterway should also be

seen within the broader context of

international trade. The advent of a global

economy has been accompanied by the

emergence of containerized shipping as well as

by the development of new markets in Asia

that has shifted the focus of international

trade from the Atlantic to the Pacific. As a

result, the ports of North America’s West

Coast are also experiencing the challenges of

congestion. In response, shippers are looking

4 Great Lakes St. Lawrence Seaway Study

Evolving patterns of trade between Asia and North America

Established trade routes

Emerging Asia-Suez route

Executive Summary
for alternative routes, one of which is to move

containerized goods from East Asia through the Suez

Canal into Europe and then continue the journey to

ports along the eastern seaboard of North America.

Such goods could then be transhipped onto carriers

that move them through the GLSLS into the heart of

North America. Given that most GLSLS shipping has

traditionally focused on bulk commodities, a key

determinant of success would be the ability of GLSLS

vessels and ports to handle containerized cargoes. 

If such capabilities are ensured, waterborne traffic can

be used to alleviate some of the pressures on regional

congestion and global restructuring. 

The GLSLS currently operates with spare capacity that could absorb traffic from other surface routes. For the marine

mode to emerge as a viable complement to the movement of goods by road and rail, the system must focus on

enhancing and maintaining its competitiveness. 

In the shipping industry, competitiveness is determined by a combination of factors: cost, time, frequency and

reliability. Clearly the cost per unit per kilometre or mile transported is a fundamental consideration and in this case,

waterborne shipping enjoys a clear advantage. That is why it is used to move large volumes of bulk goods. To compete

effectively with other transportation modes, waterborne shipping must also address other determinants of

competitiveness such as trip times and frequency of shipments.

Perhaps the most fundamental competitive consideration, however, is reliability: shippers will not use a system in which

there are frequent unplanned closures and traffic interruptions. The GLSLS offers them a high level of dependability.

Historically, it has been available to vessels for 98 percent of the regular shipping season. About two-thirds of the

remaining two percent was downtime attributable to weather (poor visibility, ice, wind), one quarter was caused by

vessel incidents, and the balance was accounted for by all other causes, including lock failures. This high level of availability is a direct result of the investments that have been and continue to be made in ongoing system maintenance. 

CURRENT CONDITION

OF THE INFRASTRUCTURE

If the GLSLS is to remain reliable, its infrastructure will have to

be maintained. The system consists of locks, shipping channels,

ports, bridges, control and communications systems, as well as

interfaces to other transportation modes. The navigation

channels accumulate silt over time and must be dredged

periodically to maintain the required depth. Locks can

experience deterioration to components such as walls and gates,

or mechanical failures that affect gate movement. There are also

a number of bridges and tunnels spanning the locks of the

Welland Canal and Montreal-Lake Ontario section of the

Seaway that must be maintained in ways that do not impede

road and rail traffic. 

While all of these diverse systemic elements form part of an integrated whole, each demands its own investments,

technologies and scheduling. Planning must factor in the specific requirements of each element in a way that

harmonizes the components of the whole system.

Great Lakes St. Lawrence Seaway Study 5

Year 

20,000,000 

40,000,000 

60,000,000 

80,000,000 

100,000,000 

2000 2010 2020 2030 2040 2050 

Traffic in forty-foot

equivalent units (FEUs)

Forecast of market for container traffic carried by all modes in the

GLSLS binational region

Executive Summary
A review of the current condition of the system was performed, with special attention devoted to the lock structures

located throughout the system. The process included the development of a “criticality index” of system components

that included factors such as availability of replacement parts, current condition, likelihood of failure and impact on

navigation. The index provided a standardized and systematic way of evaluating the current condition of the system’s

infrastructure. The condition of approximately 160 components of the GLSLS was examined: the review included

locks, approach walls, water-level control structures, road and railway bridges as well as tunnels. Analysis found that

overall, the system has held up reasonably well. Moreover, despite differences in construction and maintenance

strategies, the rankings for the sets of locks were similar from region to region. Each lock region, however, has several

critical components that have been rated as high priority and in need of repair, rehabilitation and/or replacement.

The majority of components are still serviceable, with several in need of major maintenance in future years.

Analysis has also developed models that can be

used to predict when components are likely to

fail. Criticality assessments coupled with

reliability data have identified and prioritized key

operating components with an elevated risk of

failure and significant consequences. Knowing

this allows for the adoption of a maintenance

strategy that anticipates problems rather than

dealing with them once they have occurred. 

It is possible to maintain the system by focusing

on ongoing, routine maintenance, with

components being replaced after they reach the

limit of their useful life. 

Such an approach, however, does run a higher risk

of unanticipated failure. A more proactive

strategy, however, uses reliability data to

anticipate when components are statistically

likely to fail and rehabilitate or replace those

components before failure occurs, thereby

increasing overall system reliability. 

Reliability is critical because the GLSLS is

essentially a series of structures that must be

transited with no alternatives (except at the

Welland Canal flight locks and the dual chambers

at Sault Ste. Marie). As a result, closure of one of

the structures in the series closes the entire

system. Moreover, a closure or a sequence of

closures during the navigation season can result in

incomplete vessel trips from origin to destination

and back.

The consequences of service disruption vary by

shipment and depend on the service disruption

type (closure or service time increase), location of

the disruption (at a single or dual lock chamber

site), duration and timing (beginning, middle or

end of the navigation season). Impacts from a

service disruption can include not only shipment

delay, but also return trips to unload a shipment

for rerouting on an alternative transportation

mode, vessel idling, stockpile depletion and plant 

shutdowns. Whatever the specifics, however, it is 

clear that disruptions impose significant costs on 

the transportation industry. 

6 Great Lakes St. Lawrence Seaway Study

0 100 200 300 400 500 600 700

15 

30 

90 

180 

$ Millions

Length of unscheduled closure (days) 

Soo Locks 

Welland Canal 

Montreal-Lake Ontario 

Estimated costs of unscheduled lock closure

Executive Summary

Scheduled costs under the reliable system scenario versus expected unscheduled

repair costs and transportation costs from under funding the priority components

Millions

2050

2010

2014

2018

2022

2026

2030

2036

2038

2042

2046

Proactive Maintenance Costs

Unreliable System Costs

$70.0

$60.0

$50.0

$40.0

$30.0

$20.0

$10.0

$0.0
The key, then, is to adopt a maintenance strategy that minimizes the

possibilities of disruption and maximizes overall system reliability. This is

shown in the adjacent graph, which compares the projected maintenance

costs of addressing system components in a proactive manner with the

projected impacts of system disruptions. The unreliable system costs are

significantly higher and even these are considered conservative inasmuch

as they assume that vessels incur no return trip and unloading costs, no

vessel idling costs, no stockpile depletion costs, no plant shutdown costs,

and assuming unmet tonnage flows are able to acquire alternative mode

transportation (when needed) at their long-run least-costly all-overland

alternative rate. The comparison shows the value of scheduling the

expenditure needed to maintain system reliability in a proactive manner.

The general conclusion to be drawn from this modeling is that a proactive

maintenance strategy will avoid the additional costs of unscheduled maintenance repairs and general system

unreliability. Its real benefit, however, lies in avoiding the additional transportation costs associated with

unanticipated failures: such failures lead to waiting and queuing; switching to more expensive alternative

transportation modes during closures; and ultimately switching permanently to costlier modes if the system is

perceived as unreliable. A more reliable GLSLS system with less disruptive lock events (closures, speed reductions,

etc.) is likely to attract more commercial traffic, which will, in turn, make the system more cost-effective. 

OBSERVATIONS

In general, the analysis of the current situation of the

GLSLS concluded that the system remains an

important element in the North American economy.

Its ongoing value and future prospects certainly justify

the costs of maintaining its infrastructure. Moreover,

future operation and maintenance of the system can

be performed in a manner that minimizes

environmental impacts. Given this broad consensus,

the study developed a set of specific observations for

the future of the system.

The GLSLS system is an incredibly valuable North

American asset. Marine transportation on the

waterway provides shippers with a safe, efficient,

reliable and competitive option for the movement of goods. However, there is also unrealized potential in the system

in terms of the important future contribution it could make to regional and continental transportation. The

fundamental understanding of the opportunities and challenges acquired through the course of the GLSLS Study can

be applied to identify priority areas and develop a balanced approach across economic, environmental and

engineering factors, while addressing four strategic imperatives:

1. What role should the GLSLS system play within the highly integrated North American transportation system?

2. What transportation solutions are available to guarantee a dynamic future for the waterway? 

3. What measures need to be taken to optimize the many different components of the system’s infrastructure? and

4. How should the GLSLS system sustain its operations in a way that responds to concerns about environmental integrity?

Great Lakes St. Lawrence Seaway Study 7

Executive Summary
Role in North American transportation

North America is part of a global trade network that has

experienced explosive growth over the past two decades. Part

of this growth has a geographic dimension: East and South-east

Asia have emerged as major players in international trade.

Another part involves new types of cargoes, travelling

primarily in containerized vessels. Both of these trends are

having an impact on North America as a whole and the

GLSLS system in particular.

As the volume of goods transported internationally continues to

grow, bottlenecks on North America’s West Coast are leading

shippers to look for alternative routes through both the Panama

and Suez canals. Some of this redirected traffic is finding its

way into the Great Lakes basin and St. Lawrence River region.

Yet the surface transportation routes in this region are already facing pressures. Both roads and railways are strained in

terms of increasing congestion and tightening capacity. This is exacerbated by the fact that most of this surface traffic

is funnelled through a small number of transit points, and security requirements are slowing clearance procedures at

borders. Moreover, there is limited scope for the construction of additional roads or railways to alleviate such congestion. 

The inescapable conclusion is that waterborne traffic could help to ease some of these pressures. The GLSLS is

currently operating with spare capacity that could be used to redirect some traffic from overland routes. Moreover,

redirection of traffic through the GLSLS system is directly connected with the other major trend in international

trade – the move toward containerization of cargoes. Much of the traffic now entering North America consists of

containerized shipping. As a result, when it arrives at a port of entry, shippers have a choice in how to move those

containers inland inasmuch as ships, trucks and railway cars are now all adapted to carry containers.

In the past, container ships entering northeastern North America would either discharge cargo at the main eastern

seaboard ports or carry their cargo inland as far as the Port of Montreal. Given the anticipated growth in traffic on

road and rail routes in the region, there is an opportunity to move at least some portion of this containerized cargo by

water through the GLSLS system.

For the GLSLS to emerge as a viable complement to the movement of goods by road and rail, the system must focus

on enhancing and maintaining its competitiveness. In the shipping industry, this is determined by a combination of

factors: cost, time, frequency and reliability. Clearly the cost per unit per kilometre or mile transported is a fundamental

determinant of competitiveness. In this case, waterborne shipping enjoys a clear advantage. That is why it has been

used to move large volumes of bulk goods. If waterborne shipping is to compete for more diverse cargo traffic, however,

it must also focus on the other determinants of competitiveness. Total trip times need to be shortened. Sailing fre -

quencies need to accommodate shipper requirements. Unplanned closures and traffic interruptions must be minimized.

In fact, the GLSLS system already has a good record in these areas, but any additional improvements will enhance its

overall competitiveness and strengthen its position as a viable transport alternative.

Executive Summary

OBSERVATION:

The GLSLS system has the potential to alleviate congestion on the road and

rail transportation networks as well as at border crossings in the Great Lakes

basin and St. Lawrence River region.

KEY CONSIDERATIONS:

• The GLSLS system is currently only operating at about half its potential capacity and is therefore under-utilized.

• Given projected growth in the economy and trade, all modes of transportation in both countries will be faced

with increases in traffic. When integrated with rail and trucking, the region’s marine mode can greatly increase

the overall capacity of the transportation system while reducing highway, railway and cross-border congestion.

• A research and development agenda would help to advance the use of new technologies to improve the

efficiency of marine transportation as well as strengthen its linkages to other transport modes. 

8 Great Lakes St. Lawrence Seaway Study
Solutions for a Dynamic Future

The North American transportation system is more than just the sum of its parts: it also involves linkages between

and integration of various modes and jurisdictions. Within this context, the GLSLS system cannot be thought of as a

stand-alone mode restricted to one type of traditional traffic.

The GLSLS can play an important role in contributing another set of capabilities, while offering shippers greater

flexibility. In order to fulfill this complementary role, policy and planning should focus on developing the waterway’s

shortsea shipping potential to enhance its intermodal capabilities and its ability to handle container traffic.

Optimizing the role played by the GLSLS within the transportation system of the Great Lakes basin and St. Lawrence

River region requires a holistic view of the entire system. Marine transportation must be integrated seamlessly with

the other modes in terms of cost, time, frequency and reliability.

To make this vision a reality, there are several aspects of modal integration that will have to be addressed. There needs

to be highly efficient intermodal linkages at the nodes of the system. The ports of the GLSLS system must have

suitable road and rail connections. They must also have the right kinds of equipment to move containers easily

between vessels, rail flatcars and tractor-trailers.

There are other factors which come into play in this area. There is a need for appropriate electronic tracking and

communication to direct and monitor shipments. 

New technologies, improvements in traditional infrastructure, streamlined border crossing procedures and the

harmonization of regulations will also be important in designing systems and managing the demands of enhanced

interconnectivity across transport modes.

Advancing the concept of marine intermodal services also requires suitable vessels adapted for different cargoes: bulk

commodities versus containers or neobulk shipments. The routes travelled by the cargoes also need to reflect the

potential advantages of waterborne transport. For example, shipping by vessel straight across a lake can be preferable

to moving goods around its shore along congested roads. Apart from taking a faster, more direct route, it may also be

the case that border procedures at the respective ports can be significantly faster than those at highly congested 

land crossings.

Great Lakes St. Lawrence Seaway Study 9

Executive Summary

OBSERVATION:

A stronger focus on shortsea shipping would allow the GLSLS system to be more

closely integrated with the road and rail transportation systems, while providing

shippers with a cost-effective, timely and reliable means to transport goods.

KEY CONSIDERATIONS:

• Incentives need to be identified and promoted to encourage the use of marine transportation as a

complement to the road and rail transportation modes.

• Institutional impediments that discourage the provision of shortsea shipping services need to be addressed.

• Potential opportunities to encourage the establishment of cross-lake shortsea shipping services could be

identified on a pilot project basis.

• The existing Memorandum of Cooperation and Declaration on Shortsea Shipping, adopted by Canada and

the U.S. in 2003 and 2006, respectively, could be used to continue to advance the North American shortsea

shipping agenda.
Optimizing the existing infrastructure

It is clear that the marine transportation infrastructure of the GLSLS system involves more than just a series of locks.

There are also ports and terminals, channels, bridges and tunnels, systems for control and communication, as well as

interfaces to other transportation modes. Collectively, this constitutes an integrated system that needs to be

optimized if it is to contribute to solving the transportation needs of the future.

Each of the following elements represents a distinct set of requirements, all of which need to be managed in an

integrated fashion to ensure the competitiveness of the GLSLS system.

Locks: Because of their age, locks need to be subjected to a maintenance schedule that deals with potential failures

in a way that sustains traffic with the fewest possible interruptions and preserves overall system integrity.

Shipping channels: The normal flow of water inevitably carries silt deposits that must be removed to maintain

channels at authorized depths for shipping.

Ports: Ports and terminals that are likely to support shortsea shipping or to serve as nodes in multimodal networks

will require appropriate loading and unloading facilities and equipment together with seamless links to other forms

of surface transportation.

Bridges and tunnels: There are a number of bridges and tunnels spanning the locks and channels of the Welland Canal

and Montreal-Lake Ontario section of the Seaway that must be maintained in ways that do not impede traffic. 

Control and communication: Logistics systems today depend on advanced electronic systems to monitor movements

and track shipments in real time.

Vessels: In addition to the traditional bulk carriers, there will be a need for ships capable of loading, carrying and

unloading containerized cargoes.

While all of these diverse systemic elements form part of an integrated whole, each demands its own investments,

technologies and scheduling. Planning must factor in the specific requirements of each element in a way that

harmonizes the components of the whole system.

It is clear that burgeoning trade, a capacity crunch, aging transport infrastructure and increasing pressures on

transportation lands in urban settings are an integral part of the marine environment. The locks, ports, terminals and

other infrastructure of the GLSLS are critical components of North America’s transportation gateways and, as such,

they require investment and tools to respond to market forces in a timely manner if they are to continue supporting

Canadian and U.S. international and domestic trade.

10 Great Lakes St. Lawrence Seaway Study

Executive Summary

OBSERVATION:

The existing infrastructure of the GLSLS system must be maintained in good

operating condition in order to ensure the continued safety, efficiency,

reliability and competitiveness of the system.

KEY CONSIDERATIONS:

• Any GLSLS infrastructure components identified as at risk and critical to the continuing smooth operations

of the system should be addressed on a priority basis.

• The existing GLSLS infrastructure requires ongoing capital investment to ensure that the system can

continue to provide reliable transportation services in the future.

• Modern technology, especially in areas such as control, should be used to maintain the GLSLS system in a

state that preserves its capability to respond to changing and unpredictable market conditions.

• The development of a long-term asset management strategy would help to anticipate problems with GLSLS

infrastructure before they occur and avoid potential disruptions that would reduce the overall efficiency and

reliability of the system.

• Investment options with respect to the system would involve numerous factors such as long-term planning,

innovative funding approaches, partnerships among governments and collaboration between the public and

private sectors.
Environmental sustainability

The considerations noted above must be examined within the framework of sustainable development. In simplest

terms, sustainable development means the ability to foster economic growth in a way that does not cause undue

damage to the environment. Consequently, policy and planning must factor in the environmental implications of

lock maintenance and repair, channel dredging, construction of new port facilities, or the introduction of new vessels

into the system.

The ecosystem of the GLSLS system is vulnerable to the stressors at play. Because many are not directly related to

navigation, management of or adjustments to navigational stressors are important but would not necessarily result in

appreciable gains to overall environmental quality unless they form part of an approach that is integrated with

measures in other economic sectors.

As the requirements of GLSLS operations and maintenance involve some stressors to the Great Lakes-St. Lawrence

ecosystems, these must be managed effectively. Organizational and governance frameworks, together with accompanying

policies and legislation, are likely adequate to manage and control the navigation-related activities that have a

negative impact on the environment.

There have been considerable resources devoted to research and planning but, with the exception of some specific

areas related to non-indigenous invasive species, there have been few initiatives that have seen “on-the-ground”

changes. There will be a continuation of impacts related to planned works, such as maintenance of infrastructure,

maintenance dredging and placement of dredged material, but such impacts can be minimized through effective

application of environmental assessments, remedial actions, sound environmental management strategies and 

best practices.

Yet sustainable development means more than just selecting options that have a minimal impact on the environment.

At the broadest possible level, it means attempting to build upon certain environmental advantages of marine

transportation over rail and trucking, as one component of an integrated transportation system that can be operated

in a more environmentally friendly manner. Transportation by water is significantly more fuel efficient than other

modes and consequently could reduce the emission of greenhouse gases and other pollutants. Moreover, increased

utilization of waterborne transportation could help to alleviate traffic congestion on roads, which could ultimately

result in the reduction of road maintenance and repair costs.

Great Lakes St. Lawrence Seaway Study 11

Executive Summary

OBSERVATION:

The long-term health and success of the GLSLS system will depend in part 

on its sustainability, including the further reduction of negative ecological

impacts caused by commercial navigation. 

KEY CONSIDERATIONS:

• The GLSLS system should be managed in a way that prevents the inadvertent introduction and

transmission of non-indigenous invasive species and supports the objectives of programs designed to

minimize or eliminate their impact.

• The existing sustainable navigation strategy for the St. Lawrence River could be extended to the Great

Lakes basin.

• The movement and suspension of sediments caused by shipping or operations related to navigation should

be managed by developing a GLSLS system-wide strategy that addresses the many challenges associated

with dredged material and looks for beneficial re-use opportunities.

• Ship emissions should be minimized through the use of new fuels, new technologies or different 

navigational practices.

• Islands and narrow channel habitats should be protected from the impacts of vessel wakes.

• There is a need to improve our understanding of the social, technical and environmental impacts of 

long-term declines in water levels as related to navigation, and identify mitigation strategies.

• Improvements should be made to short- and long-term environmental monitoring of mitigation activities.
MONITORING AND FOLLOW-UP

The observations and key considerations emerging from the GLSLS Study are the result of a comprehensive, multiyear research effort involving dozens of experts and specialists. Moreover, they reflect a consensus among the seven

participating agencies. This is, in itself, a unique milestone in the history of the GLSLS.

The success of any initiative to build the future of the GLSLS system depends on a commitment by government and

industry in both Canada and the U.S. to clear objectives and to the continuous monitoring of progress and success.

Canada and the U.S. should maintain their collaborative efforts to plan the future of commercial navigation on the

GLSLS system through a binational body of governmental representatives. The role of this body would be to monitor

the progress achieved in the areas identified as priorities in the GLSLS Study. The two countries would work in

partnership to pursue an appropriate policy framework, promote the opportunities represented by the system to other

parts of government and ensure an integrated approach to the distinct imperatives of the economy, the environment

and engineering. Ultimately, the sustainability of the GLSLS system depends on achieving a viable balance of these

three perspectives.

The understanding gained from the expertise of those who contributed to the GLSLS Study can be used to inform

Canadian and U.S. decision-makers. The study has identified observations and key considerations that need to be

taken into account in order to optimize the operations and maintenance of the GLSLS system and ensure it

continues to serve North America’s economy over the next 50 years.

12 Great Lakes St. Lawrence Seaway Study

Executive Summary
CHAPTER 1

Introduction

The Great Lakes St. Lawrence Seaway system 

is a vital waterway that has played a critical role in the

economic evolution and prosperity of North America. 

The system as we know it today, however, is more than half

a century old and is beginning to show the effects of age. 

In response, the governments of Canada and the 

United States undertook a joint effort to assess the system’s

current infrastructure condition and future commercial

prospects within the broader context of regional

environmental stewardship.
For more than half a century, the Great Lakes 

St. Lawrence Seaway (GLSLS) system has served as a

vital transportation corridor for the single largest

concentration of industry in the world. Straddling the

Great Lakes basin, North America’s industrial heartland

depends on this intricate system of locks, channels, ports

and open water. 

Yet the waterway is facing new challenges that could not

have been anticipated when the last link in the chain,

the St. Lawrence Seaway, came into full operation in

1959. Changes in the economy have altered product

demand and traffic patterns while the evolution of the

transportation industry has affected vessel dimensions.

As a result, shipping volumes have

fluctuated and the system’s

underlying economic drivers have

been transformed. Still, the GLSLS

continues to fulfill a vital transport

function not only for the Great

Lakes and St. Lawrence regions,

but also for the entire industrial

core of the North American

economy. Given its ongoing

importance and in light of growing

congestion at border crossings and

on other transport modes, it is

essential that the system be

maintained as a safe, reliable,

efficient and sustainable component

of the continent’s overall

transportation network. 

A system as large and complex as

the GLSLS inevitably affects the

environment around it. Generally,

society has become far more aware of such

environmental impacts, exacerbated as they are by the

parallel pressures of population growth, urbanization and

changes in lifestyle. Recent scientific research has

yielded a better understanding of the cumulative effect

of human action on the environment. It has also led to

an enhanced appreciation of complex environments

such as the Great Lakes basin and the St. Lawrence

River, and has transformed the way in which such

ecosystems are studied and evaluated.

The infrastructure of the GLSLS is starting to show its

age. After 50 to 75 years of service, the system of locks

and channels shows wear and tear from several hundred

thousand vessel transits. As the system ages, the

demands of maintenance grow, as do its costs. 

14 Great Lakes St. Lawrence Seaway Study

Introduction

In light of these cumulative changes, the governments

of Canada and the United States (U.S.) undertook a

comprehensive review of the GLSLS system. On 

May 1, 2003, they signed a memorandum of cooperation

that provided for their collaboration in a wide-ranging

study intended to address the fundamental question:

What is the current condition of the GLSLS system, and

how best should we use and maintain the system, in its

current physical configuration, in order to capitalize on the

opportunities and face the challenges that will present

themselves in coming years?

Seven Canadian and U.S. federal departments and

agencies were involved in this initiative: Transport

Canada, the U.S. Department of

Transportation, the U.S. Army

Corps of Engineers, the Canadian

St. Lawrence Seaway Management

Corporation, the U.S. Saint

Lawrence Seaway Development

Corporation, Environment Canada

and the U.S. Fish and Wildlife

Service. All of them participated in

a steering committee responsible

for the project’s overall strategic

direction. Responsibility for

overseeing the study tasks and

analysis was vested in a manage -

ment committee consisting of 

one representative from Transport

Canada and one from the U.S.

Army Corps of Engineers. 

The study was carried out by

subject-matter experts and

representatives drawn from the

seven partners and organized into three working groups:

economic, engineering, and environment. 

The mandate of the Economic Working Group was to

consider the current economic role of the GLSLS and

its likely future evolution. It was to examine the nature

and directions of historical and present-day traffic flows

and project the kind of traffic that might be expected

over the coming half century. This was intended to

estimate the future economic importance of the GLSLS

as a key factor in determining the infrastructure that will

be needed to support it.

What is the current condition

of the GLSLS system, and

how best should we use and

maintain the system, in its

current physical configuration,

in order to capitalize on the

opportunities and face the

challenges that will present

themselves in coming years?
The Engineering Working Group was tasked with

examining the current condition of the GLSLS system’s

physical infrastructure. It was directed to identify

potential problem areas, estimate costs associated with

keeping the system functional, and articulate an optimal

strategy for ensuring its reliable ongoing operation. 

The Environment Working Group was directed to review

the current state of the environment in the Great Lakes

basin and St. Lawrence River. It was to identify the most

valued components of this ecosystem and determine

how they had been affected by commercial navigation.

Ultimately the group was to suggest ways of ensuring

that the future environmental impact of commercial

navigation could be minimized. 

Stakeholder engagement was an important component

of the study process, given its size and scope. From the

outset, there was clear recognition of the need to consult

with stakeholders in order to obtain their comments,

determine their interests, and identify issues of concern. 

Introduction

Great Lakes St. Lawrence Seaway Study 15

Meetings with interested parties

from both the public and private

sectors were held initially in June

and July 2004, and then again in

September 2005. These sessions

were instrumental in engaging

stakeholders, informing them about

study objectives and soliciting 

input on their concerns. Opinions

were voiced, presentations were

made and submissions were gathered.

Not only did the meetings serve to

assemble information and expertise,

but they also provided a forum for

the exchange of ideas, notably on

important environmental issues and

concerns. The input gathered at

these sessions was transmitted to 

the management committee, to the

study working groups and to all

study partners for their

consideration. 

As a major binational undertaking,

the study was mandated to conduct

an extensive review of the existing

infrastructure of the GLSLS in its

current configuration. Despite its

breadth and depth, there are issues

that the study deliberately did not address. The focus

was restricted to commercial navigation and excluded

the navigational issues relating to recreation or tourism.

In addition, the study did not consider any changes to

the existing configuration of the GLSLS system such as

larger locks, deeper channels, double lock systems or

turning basins, nor did it review issues such as extending

the navigational season and deferred any consideration

of the possible impacts of long-term climate change.

Finally, while the role played by commercial navigation

in the introduction of aquatic non-indigenous invasive

species is taken into consideration, the study did not

address the specifics of possible future remedial measures

such as regulations affecting the treatment of ballast water. 

In evaluating the infrastructure needs of the GLSLS

system as they pertain to commercial navigation, the

study focused on the engineering, economic and envi ron -

mental implications of those needs. This document

integrates the findings from each of these three perspectives

to provide a broad assessment of the current status of the

GLSLS as well as an indication of opportunities and

challenges in the coming years.

Satellite view of the Great Lakes

Source: U.S. Army Corps of Engineers
This study constitutes the first comprehensive assess -

ment of the physical state of the GLSLS. It has enhanced

the understanding of the system’s physical dynamics in

terms of wear, material fatigue and concrete conditions.

So far, despite the age of its infrastructure, the system

continues to provide highly reliable service. It is, however,

time to re-evaluate current practices and to define a

maintenance and rehabilitation strategy that will

accommodate the needs of the next 50 years. 

How that maintenance strategy will be implemented

depends on the future role that the waterway is expected

to play and the funding decisions of both Canada and

the U.S. It is clear that the system will continue to

make a vital economic contribution to the region. 

The traffic currently moving through the system could

not be transferred to road and rail without incurring

congestion, inefficiencies and additional greenhouse gas

emissions that would have a significantly negative impact

on both economic efficiency and the environment.

Traffic forecasts presented in this report show that the

bulk trade presently carried through the system is likely

to experience modest but steady growth.

Beyond that and within the context of the existing

physical infrastructure, new opportunities are emerging

from the possibility of introducing containerization 

into the GLSLS. However, in order to realize these

opportunities, analysis shows that the reliability of the

system must be maintained.

In order to maximize the dependability of the GLSLS,

while making the most efficient and prudent use of

public funds, a system-wide reliability analysis has been

undertaken. Different system maintenance scenarios have

been examined to evaluate their impact on reliability,

their relative costs and their implications for marine

freight traffic on the waterway. 

Complementing the engineering perspective, the

environmental component of the study compiled infor -

mation necessary to determine the current condition of

valued environmental resources that could potentially

be affected by navigation-related activities on the

system. It assessed the potential impacts of future traffic

projections and different system maintenance scenarios.

It then identified the kinds of management actions 

that are needed to minimize environmental impacts in

the future.

16 Great Lakes St. Lawrence Seaway Study

Introduction

This report summarizes the findings of the various study

teams and working groups, and it synthesizes material

taken from dozens of reports, studies and evaluations. 

It has deliberately been written in non-technical

language to make the findings of the GLSLS Study

accessible to the broadest possible audience of policymakers and interested stakeholders. 

The GLSLS Study has been a major, multi-year

undertaking, involving more than 50 experts and

authorities in a wide variety of fields. Ultimately, the

understanding gained from their expertise can be used 

to inform Canadian and U.S. decision-makers who are

developing strategies and options for ongoing system

monitoring and maintenance. The analysis presented

constitutes a solid foundation upon which to build a

cost-effective and sustainable system-wide asset

management strategy for the future.
The Waterway

The Great Lakes St. Lawrence Seaway system is situated within

North America’s industrial heartland. Emerging in tandem with the

development of that heartland, it has played and continues to play 

a vital role, not only in sustaining economic development 

throughout this region, but in supporting its international 

competitiveness. As an integral component of the region’s overall

transportation network and trade corridor, the system comprises 

many inter-related elements including locks, water channels, ports,

ships, multimodal linkages, as well as organizations dedicated to its

service and support. It is this complex interplay of diverse 

elements that must be addressed when forging a strategy 

to meet emerging challenges and ensure that marine 

transportation on the waterway continues its contribution 

to prosperity in the future.

CHAPTER 2
As a major commercial artery, the Great Lakes St. Lawrence

Seaway (GLSLS) constitutes an essential component of

an integrated economic system that spans the basins of

the Great Lakes and St. Lawrence River and extends

into the surrounding hinterland. Indeed, the GLSLS

system lies at the heart of what has become one of the

largest and most dynamic economic hubs in the world.

It serves producers and manufacturers that account for

about one third of the North American economy. As a

result, it is a region of high transport intensity with huge

volumes of freight moving by road, rail, air, water or a

combi nation thereof. Within this vibrant market, the

GLSLS supports and strengthens regional, continental

and intercontinental economic relationships by

providing low-cost, waterborne, bulk transportation. 

SYSTEM OVERVIEW

The navigable waterway extends from the Atlantic Ocean

at the Gulf of St. Lawrence through the St. Lawrence

River and into all of the Great Lakes. It consists of

channels through the St. Lawrence, Detroit, St. Clair

and St. Marys rivers, which are dredged where necessary

to provide adequate vessel draft. It also consists of 

18 Great Lakes St. Lawrence Seaway Study

Chapter 2

canals and locks that allow ships to bypass the rapids

and falls in these rivers. Measured from Sept-Îles,

Quebec, in the Gulf of St. Lawrence to the lakehead at

Duluth, Minnesota, this waterway extends a total of

3,700 kilometres (km) (2,300 miles). Its locks allow

ships to be raised more than 180 metres (m) (600 feet)

from sea level to the level of Lake Superior.

Chicago 

(9.4 m) 

Cleveland 

(2.1 m) 

Toronto 

(5.9 m) 

Montreal 

(3.7 m) 

Detroit 

(4.5m) Provinces and states bordering 

GLSLS (total population 110 million)

5 largest urban areas (population in brackets)

Great Lakes and St. Lawrence River 

drainage basin (total population 33 million)

GLSLS waterway

FIGURE 2.1

The GLSLS system within North America

1 Source: Statistics Canada and the U.S. Bureau of Economic Analysis.

THE ECONOMIC IMPORTANCE OF THE

GLSLS REGION1

• 110 million people (one quarter of North America’s

population) live in the adjoining provinces and states

(Ontario, Quebec, New York, Pennsylvania, Ohio,

Michigan, Indiana, Illinois, Wisconsin and Minnesota).

• In 2006, Ontario and Quebec accounted for 58 percent 

of Canada’s gross domestic product (GDP).

• In 2005, the eight states in the region contributed 

28.5 percent to U.S. GDP.

• The combined regional GDP was $4.3 trillion in 2005.

• The region accounts for 55 percent of North America’s

manufacturing and services industries and about half of all

North American retail sales.
ORIGINS

Since humans first settled in the region, the waters of

the Great Lakes basin and the St. Lawrence River have

served as a transportation corridor. That corridor

evolved in step with the developing needs of the

Canadian and American economies. Initially, its primary

function was to support internal linkages across the

region. Eventually, it also came to provide North

America’s industrial heartland with direct access to the

markets of the world. 

Because the waterway presents significant changes in

elevation as a result of rapids or falls, starting in the

eighteenth century, canals and locks were built and 

re-built to circumvent these natural barriers. The

culmination of this process occurred in 1959, when the

Seaway was opened with locks large enough to carry

freighters and ocean-going vessels efficiently throughout

the system. 

The original vision for the Seaway focused specifically

on the grain and ore trades. By the 1950s, the ability of

railways to haul bulk commodities had reached a

capacity limit. Nowhere was this more evident than in

an expanding grain trade. Grain from

the Prairies had traditionally been

hauled in small volumes by rail from

the Lake Superior lakehead at Thunder

Bay and Duluth or from the ports of

Georgian Bay. From there, it was taken

to Montreal and to other eastern ports

for export or domestic use. With the

world’s grain trade growing, however,

rail was no longer able to accommodate

the rising volumes associated with 

this traffic. 

Industrial expansion after World War II

created another need for efficient

regional and international shipping.

This involved the movement of iron

ore both from the Quebec-Labrador

region into the Great Lakes basin, and

from the Mesabi Range in Minnesota

to mills in Indiana, Ohio and Ontario. 

The need to move larger volumes of

grain and iron ore cost-effectively was

the impetus behind the long-planned

development of the Seaway, a system of

15 locks able to support the passage of

ocean-going vessels from the St. Lawrence River into

Lake Erie. After four years of construction, the waterway

became operational in 1959, opening up the North

Great Lakes St. Lawrence Seaway Study 19

The Waterway

American industrial heartland to ocean-going shipping.

The ensuing surge in traffic lasted for more than two

decades and ushered in a period of rapid economic

development throughout the adjacent provinces and

states. Since its opening, the Seaway has moved more

than 2.3 billion metric tons of cargo. 

These improvements to navigation were paralleled by a

similar expansion of capacity at Sault Ste. Marie, where

navigation was impeded by a drop of 6.4 m (21 ft) as the

St. Marys River falls from Lake Superior to the level of

Lake Huron. Here, too, the original intent was to

support the export of grain and agricultural products as

well as ore and other raw materials. A key consideration

at the time was to supply the American steel mills along

the southern shores of the system with increasing

amounts of iron ore and coke for smelting.

Upgrading of the Davis and Sabin locks at Sault Ste. Marie

had occurred in the second decade of the twentieth

century and the MacArthur Lock was opened in 1943.

Development culminated, however, with the giant 

Poe Lock, which had been built in 1896, but which was

rebuilt in the mid 1960s to handle large laker traffic up

to 300 m (1,000 ft) in length; it was finally opened for

navigation in 1969. 

Opening of the Seaway in 1959.

Source: The St. Lawrence Seaway Management Corporation
The GLSLS system as it exists today is the culmination

of centuries of systematic enhancements designed to

move ships easily across a vast expanse of territory in

which water falls more than 180 m (600 ft) as it flows

from Lake Superior to the Atlantic Ocean. Since most of

this change in elevation occurs over rapids or falls, a

series of canals and locks have been built to raise and

lower vessels across these natural barriers. 

In addition to locks, the system depends on channels

through the St. Lawrence, Detroit, St. Clair and 

St. Marys rivers. These are dredged where necessary to

provide adequate draft for vessels moving through these

passages. There is also a wide range of supporting

infrastructure and services that include:

• port terminals, docks, loading facilities and port

authorities;

• port services (docking, loading, unloading, etc.);

20 Great Lakes St. Lawrence Seaway Study

Chapter 2

FIGURE 2.2

Key features of the GLSLS system

THE SYSTEM TODAY THE GLSLS AT A GLANCE

Main waterways: the five Great Lakes, the St. Marys River, 

Lake St. Clair, the Detroit River, the St. Lawrence River and the

Gulf of St. Lawrence

Waterway and port infrastructure: 6 canals, locks located at 

16 different sites, serving 15 major international ports and more

than 50 regional ports on both sides of the border

Cargo shipped through the Seaway locks since 1959: 2.3 billion

metric tons valued at $350 billion 

Cargo shipped through the Soo locks since 1959: 4.2 billion tons 

Direct economic contribution: Every year, U.S. commercial traffic

through the GLSLS system generates more than $4.3 billion in

personal income, $3.4 billion in transportation-related revenue and

$1.3 billion in federal, state and local taxes 

Thunder Bay

Green Bay

Milwaukee

Chicago

Detroit

Monroe

Hamilton

Toronto

Prescott

Valleyfield

Montreal

Trois-Rivieres

Quebec

Sept Iles

Port-Cartier St. Lawrence

Lake Ontario

Lake Erie

Lake Huron

Lake Michigan

Lake Superior

Toledo

Burns

Harbour

LOCKS

1 St. Lambert

2 Cote Ste. Catherine

3 Lower Beauharnois

4 Upper Beauharnois

5 Snell

6 Eisenhower

7 Iroquois

8 Welland Canal (8 locks)

9 Soo Locks

PORTS

CANADIAN LOCKS

UNITED STATES LOCKS

Windsor

Sarnia

Cleveland

Lorain

Ashtabula

Conneaut

Erie

Buffalo

Sault Ste. Marie

Goderich

Oswego

Ogdensburg

Becancour

Baie Comeau

Sorel

Oshawa

Duluth/

Superior

Source: The St. Lawrence Seaway Management Corporation, the Saint Lawrence Seaway Development Corporation

• marine navigation services, pilotage, and ice-breaking

services; 

• shipping companies, and shipping and logistic service

providers; and

• various services associated with lock maintenance 

and support.
Finally, the ports of the GLSLS 

serve as nodes in a vast multimodal

transportation network that also

includes more than 40 highways and

30 railway lines. As a result, the

GLSLS is deeply embedded in the

transportation infrastructure of the

entire region. 

The GLSLS system consists of four

distinct sections: the Great Lakes, the

Welland Canal, the Montreal-Lake

Ontario section, and the St. Lawrence

ship channel. Each of these is described

in detail in the pages that follow. 

Great Lakes St. Lawrence Seaway Study 21

The Waterway

FIGURE 2.4

Schematic of the profile of the GLSLS in steps from Lake Superior to the Atlantic Ocean

FIGURE 2.3

Major highways and railways within the GLSLS region

DULUTH TO ATLANTIC : 3,700 KILOMETRES (2,342 MILES)

Metres (feet) above sea level

Lake Superior: 616.3 km (383 mi.)

St. Marys River: Soo Locks: 112.6 km (70 mi.)

Lake Michigan: 555.2 km (345 mi.)

Lake Huron: 358.5 km (223 mi.)

St. Clair River-Lake St. Clair-Detroit River: 123.9 km (77 mi.)

Lake Erie: 379.7 km (236 mi.)

Welland Canal: Eight Locks: 45 km (28 mi.)

Lake Ontario: 257.4 km (160 mi.)

Thousand Islands Section: 109.4 km (68 mi.)

Lake St. Lawrence: 70.8 km (44 mi.)

International Rapids Section: Three Locks and Dams: 70.8 km (44 mi.)

Lake St Louis

Lake St. Francis Section: 48.2 km (30 mi.)

Soulanges Section: Two Locks: 25.7 km (16 mi.)

Lachine Section: Two Locks: 49.8 km (31 mi.)

Tide Water Section: Deep Water from Montreal to Sea: 1609.3 km (1000 mi.)

6 (20’)

Canadian Highway

U.S. Railway

Canadian Railway

U.S. Highway 

Border Crossing

21 (69’) 46.6 (153’)

75 (246’) 73.7 (242’)

174.3 (572’) 183.4 (602’) 176.3 (578.5’)

Sea Level

Source: The St. Lawrence Seaway

Management Corporation, the Saint Lawrence

Seaway Development Corporation
This is the navigational system linking Lakes Superior,

Michigan, Huron and Erie. It includes the connecting

channels of the St. Marys River, the Straits of Mackinac,

and the Detroit–St. Clair rivers system. 

There are five locks at Sault Ste. Marie, though the

small lock on the Canadian side is only used for

recreational craft. On the American side, the Soo Locks

consist of four parallel locks (Poe, MacArthur, Sabin

and Davis), all of which are administered by the Great

Lakes and Ohio River Division of the U.S. Army Corps

of Engineers (USACE). At present, only the two largest

locks, the MacArthur and the Poe, serve commercial

navigation. The MacArthur Lock chamber can

accommodate vessels of the “Seaway Max” class, which

is 225.5 m (740 ft) long with a 23.8 m (78 ft) beam.

The Poe Lock can accommodate “1,000-footer” vessels

that are up to 308.9 m (1,014 ft) long with a 32 m 

(105 ft) beam. The draft available for shipping is

nominally 7.77 m (25.5 ft), but this varies with

fluctuations in lake levels.

22 Great Lakes St. Lawrence Seaway Study

Chapter 2

THE GREAT LAKES

Satellite photo of the 

Great Lakes

Source: SeaWiFS Project

NASA/GSFC and GeoEye

TABLE 2.1

Lake characteristics

Superior Michigan Huron Erie Ontario

Elevation in metres (ft) 182 (598) 176 (577) 176 (577) 173 (569) 74 (243)

Average depth in metres (ft) 147 (483) 85 (279) 59 (195) 19 (62) 86 (283)

Maxiumum depth in metres (ft) 406 (1,332) 282 (925) 229 (750) 64 (210) 244 (802)

Water area in km2 (mi2) 82,100 (31,700) 57,800 (22,300) 59,600 (23,000) 25,700 (9,910) 18,960 (7,340)

Shoreline length in km (mi) 4,385 (2,726) 2,633 (1,638) 6,157 (3,827) 1,401 (871) 1,146 (712)

Volume in km3 (mi3) 2,900 1,180 850 116 393

SOME FACTS

Compensating gates controlled by the International Joint Commission are used to regulate the water

level in Lake Superior. The rapids just below these gates are important spawning grounds. 

There are power canals and generating stations on both the Canadian and American sides of the river.

This includes the Edison plant with its power canal running through Sault St. Marie, Michigan. 

Lakers using the waterway serve three primary purposes: they carry iron ore and coal for domestic steel

production; they transport coal for electricity generation; and they move limestone for cement

production. 

Because the upper lakes ships operate exclusively in freshwater, they experience less corrosion and enjoy life

spans of up to 50 years as compared to 25 years for ocean-going ships. 
Bulk cargo vessels known as “lakers” and designed

specifically for the Great Lakes dominate this waterway.

The vast majority of vessels are self-unloading dry bulk

carriers. Cargo is released through hatches that feed a

conveyor belt running along the bottom of the ship.

Bulk material is carried along the conveyor and lifted up

and out onto the adjacent dock via a pivoting boom.

This configuration allows vessels to unload their cargoes

at a rate of up to 10,000 metric tons per hour without

the need for any shoreside personnel or equipment.

Among these is a fleet of 13 American “1,000-foot”

lakers that are the longest ships on the GLSLS system.

By far the single largest trade in the entire GLSLS

system consists of the bulk cargoes of ore and coal carried

by lakers from the Port of Duluth-Superior downstream

as far as Lake Erie. 

Great Lakes St. Lawrence Seaway Study 23

The Waterway

Aerial photo of the Soo Locks 

Source: U.S. Army Corps of Engineers

225.5 m (740 ft.) 

308.9 m 

(1,014 ft.) Seaway 

lock width 

24.4 m (80 ft.) 

Seaway lock 

length 233.5 m 

(766 ft.) 

23.8 m 

(78 ft.) 

Seaway Max Vessel

Up to 225.5 metres long (740 feet) 

and 23.8 metres wide (78 feet).

1000-Footer Vessel

308.9 metres long (1,014 feet)

and 32 metres wide (105 feet).

Limited to travel within

the Great Lakes above the

Welland Canal.

32 m 

(105 ft.) 

FIGURE 2.5

Vessels of the Great Lakes

VESSELS OF THE GREAT LAKES

Most U.S.-flagged domestic vessels

(“Lakers”) are by far the largest vessels

on the Great Lakes, with some vessels

over 300 metres (1,000 feet) in length.

Their size prevents them from transiting

the Welland Canal, and so they trade

exclusively in the upper four Great

Lakes.

Canadian-flagged domestic vessels

(“Canadian lakers”) are generally built

to ‘Seaway Max’ dimensions, enabling

them to call at ports through out each of

the five Great Lakes, the St. Lawrence

River, and in some cases, ports outside

the GLSLS system.

Seaway-sized transoceanic vessels (“salties”)

are approximately 180 metres (600 feet)

long and able to enter the lakes from

overseas, transit the St. Lawrence

Seaway, Welland Canal, and all five

Great Lakes.
The Welland Canal is one of the two components of the

St. Lawrence Seaway, which connects Lake Erie and

Lake Ontario to the St. Lawrence River and to the

Atlantic Ocean. 

The canal allows for navigation between lakes Erie and

Ontario, bypassing the 99 m (326 ft) drop of the

Niagara River at Niagara Falls. The Welland Canal is

composed of eight Canadian locks extending over 42 km

(26 miles). Its locks accommodate more than half of the

change in elevation between Lake Superior and sea

level. Port Colborne on Lake Erie, marks the upstream

24 Great Lakes St. Lawrence Seaway Study

boundary of the Welland Canal with Port Weller on

Lake Ontario as its downstream boundary. Its locks can

accommodate the standard “Seaway Max” vessels that

are 225.5 m (740 ft) long and 23.8 m (78 ft) wide. 

The canal’s nominal draft is 8.08 m (26.6 ft). 

Chapter 2

THE WELLAND CANAL

One of the gates of the

Welland Canal

Source: The St. Lawrence Seaway

Management Corporation

FIGURE 2.6

Profile of the Welland Canal

SOME FACTS

Navigation canals through Welland to bypass Niagara Falls have existed

since 1829. This current system is the fourth of these canals. 

It was opened in 1932 and experienced minor modifications in the

1950s to adapt to Seaway specifications.

A siphon allows the Welland 

River to cross perpendicular

to the canal by flowing

underneath the canal in a

large concrete culvert.

Twinned flight locks (Locks 

4, 5, 6) climb the steepest

portion of the canal. Flight

locks are typically slower to

navigate so they are twinned

(parallel) to speed traffic.

These flight locks and the

Soo Locks are the only

parallel locks in the GLSLS

system.

LAKE

ONTARIO

LAKE ERIE

LOCK

8

LOCKS

LOCKS

7

6

5

4

3

2

1

WELLAND RIVER

AVERAGE LOCK LIFT: 14.2 METRES (46 FEET, 7 INCHES)

NIAGARA ESCARPMENT: 

99.5 METRES (326 FEET, 3 INCHES)
The seven lifts are located in the

northern 11.6 km (7.2 miles) section of

the canal, between Lake Ontario and

the top of the Niagara escarpment. 

A 27.8 km (17.3 miles) man-made

channel runs through level ground 

to the shallow-lift control lock at 

Lake Erie. Piers projecting into the

lakes account for an additional 4 km

(2.5 miles).

The Welland

Canal provides

more than half the

lift needed between

tidewater and the

Lakehead.

Great Lakes St. Lawrence Seaway Study 25

The Waterway

Closer view of the locks 4, 5 and 6 at Thorold (Welland Canal)

Source: Thies Bogner, photographer

Aerial view of the Welland Canal 

Source: Thies Bogner, photographer
The Montreal-Lake Ontario (MLO) section extends

approximately 300 km (186 miles) along the St. Lawrence

River from Lake Ontario to the Port of Montreal. Water

from Lake Ontario falls a total of 74 m (243 ft) before it

reaches sea level in the Gulf of St. Lawrence. 

The MLO section consists of seven locks: the Iroquois,

Upper and Lower Beauharnois, Côte Ste. Catherine and

St. Lambert locks on the Canadian side of the waterway,

and the Dwight D. Eisenhower and Bertrand H. Snell

locks on the American side. 

26 Great Lakes St. Lawrence Seaway Study

This section of the waterway carries both overseas

imports and exports as well as bulk goods (ore, coal,

minerals, etc.) moving within the system. 

Vessel size is limited by lock geometry, which allows for

a maximum vessel length of 225.5 m (740 ft) and a

beam of 23.8 m (78 ft). Its nominal draft of 8.08 m 

(26.6 ft) is the same as that of the Welland Canal.

Chapter 2

THE MONTREAL-LAKE ONTARIO SECTION

SOME FACTS

The Canadian Iroquois Lock is between the levels of Lake Ontario on its upstream side and Lake St. Lawrence on its downstream

side. The small head difference at this lock permits the use of sector gates rather than the massive mitre gates used elsewhere in

the system.

Upstream of Montreal is the Beauharnois Canal (21 km or 13 miles long). The Upper and Lower Beauharnois locks are located 

here beside the Beauharnois hydroelectric dam and generating station. Downstream of Beauharnois is Lake St. Louis and the 

City of Montreal.

The ship channel bypasses the Lachine rapids via the 22.5 km (14 miles) long Canadian South Shore Canal. There are two locks in

the canal, Côte Ste-Catherine Lock at the upstream end and the St. Lambert Lock at the downstream end.

The two American locks are located between Montreal and Lake Ontario. They span the head difference controlled by the MosesSaunders dam and generating station. 

The upstream U.S. Eisenhower Lock is connected to the downstream Snell Lock by the Wiley-Dondero ship channel.

At the Eisenhower Lock, access to the 

Moses-Saunders generating station is obtained via

a tunnel passing through the lock sill.

Aerial view of the Eisenhower Lock

Source: Saint Lawrence Seaway Development Corporation
The MLO section opened the North American

heartland to international shipping, and vessels from all

over the world now make their way to St. Lawrence and

Great Lakes ports carrying the large quantities of finished

products, manufactured iron and steel and general cargo

imported by Canada and the United States. Return

voyages can include a myriad of cargoes from the inland

industrial centres.

The navigation season on the waterway extends

generally from late March to late December. Since the

Seaway opened in 1959, new technologies against ice

formation in locks and canals have been implemented

and more than 25 days have been added to the shipping

season. Between the opening of the Seaway in 1959 

and 2006, the Seaway carried more than 2.3 billion

metric tons of cargo. The rational utilization of ships

which may carry one commodity upbound (such as iron

ore) and a different commodity downbound (such as

grain) makes the Seaway a competitive mode of

transportation for a wide variety of bulk products and

project cargoes.

Great Lakes St. Lawrence Seaway Study 27

The Waterway

FIGURE 2.7

MLO locks profile

LAKE

ONTARIO

SW NE ➤

ONTARIO

➤

NEW YORK

LAKE

ST. FRANCIS

LAKE

ST. LOUIS

MONTREAL

HARBOUR

Kingston

Cape

Vincent

Clayton Alexandria

Bay Ogdensburg

Prescott

Iroquois

IROQUOIS LOCK

(CANADA)

DWIGHT

EISENHOWER

LOCK

(U.S.)

Morrisburg Cornwall

Massena

Thousand

Islands

Bridge

International

High Level 

Bridge

Champlain

Bridge

St. Louis

Bridge

Valleyfield

Bridge

OgdensburgPrescott

Bridge

BERTRAND

SNELL LOCK

(U.S.)

UPPER

BEAUHARNOIS

LOCK

(CANADA)

LOWER

BEAUHARNOIS

LOCK

(CANADA)

COTE STE.

CATHERINE

LOCK

(CANADA)

ST. LAMBERT

LOCK

(CANADA)

Aerial view of St. Lambert Lock

Source: The St. Lawrence Seaway Management Corporation
The St. Lawrence ship channel is the navigation

channel that is maintained downstream of the last lock

of the GLSLS system. It runs between the Port of

Montreal and the Gulf of St. Lawrence on the Atlantic

Ocean. It has no locks and is open to year-round

navigation. 

Originally, ocean-going vessels could only reach Quebec

City before their cargo had to be transshipped onto

vessels with shallower drafts for passage into the 

interior. Most of the rapids along the channel became

navigable with the advent of increasingly powerful

steamboats able to navigate through them. 

Navigation across three particularly difficult sections

(Montreal–Lachine, Pointe-des-Cascades–Coteau

Landing, Cornwall–Dickinson’s Landing) was made

possible when canals were built there. The entire

channel was systematically deepened throughout the

19th and early 20th centuries. As a result, Montreal

replaced Quebec City as the leading port on the 

St. Lawrence River.

28 Great Lakes St. Lawrence Seaway Study

Chapter 2

THE ST. LAWRENCE SHIP CHANNEL

SOME FACTS

The St. Lawrence ship channel has no locks and is open to

year-round navigation. Icebreaking operations during

winter months allow vessels to navigate from the Atlantic

up to Montreal.

The majority of the commercial traffic flows includes vessels

that are larger than the maximum Seaway size, like oceangoing vessels transporting containers or large bulk carriers.

The dredging performed in various points within the 

channel and at ports is necessary to ensure continuous 

safe navigation.

This natural channel is one of the most important

ecosystems in Canada. The movement of ships takes them

through different ecosystem components (rivers, lakes,

estuary) that vary in terms of fragility.

The saltwater goes up to the eastern edge of Île d’Orléans,

and this fluvial section is subject to tides.

Ship in ice

Source: Port of Montreal

Vessel passing through the

Lake Saint-Pierre, Quebec

Source: Environment Canada

Vessel arriving at the 

Port of Montreal, Quebec

Source: Environment Canada
Today, the St. Lawrence ship

channel serves both shipping that is

internal to GLSLS trade as well as

the ocean-going traffic of vessels

that are larger than the maximum

Seaway size. The latter includes

container ship traffic moving to and

from the Port of Montreal as well as

the large bulk carrier traffic

(particularly oil tankers) serving the

Port of Quebec. The nominal draft

of the waterway from Quebec City

to Montreal is 10.7 m (35.1 ft), 

but the navigation channel is main -

tained to a depth of 11.3 m 

(37.1 ft) to provide adequate 

clearance for ships. 

Great Lakes St. Lawrence Seaway Study 29

The Waterway

Satellite view of the Gulf of St. Lawrence

Source: NASA, Visible Earth 

Containerized cargo at the Port of Montreal, Quebec

Source: Transport Canada

CONTAINER SHIP TRAFFIC MOVING TO

AND FROM THE PORT OF MONTREAL

The Port of Montreal handles all types of cargo

year-round and is a leader among the container

ports serving the North Atlantic market, and the

international port closest to North America’s

industrial heartland.

The port’s containerized cargo is made up of a wide

variety of products reflecting the industrial mix of

Central Canada and the U.S. Midwest and

Northeast.

The port typically handles ocean-going container

ships with capacity up to 4,500 twenty-foot

equivalent units (TEUs). These ships are too

large to transit the Seaway locks.
SYSTEM

OPERATION AND

MANAGEMENT

Responsibility for management 

and operation of GLSLS system

infrastructure rests with several

government agencies and private

enterprises. 

The Government of Canada owns all

of the fixed assets of the Canadian

portion of the Seaway. The St. Lawrence

Seaway Management Corporation

(SLSMC), a not-for-profit entity

established by Seaway users and other

interested parties, has been contracted

to assume responsi bility for the

operations and main tenance of the

Canadian portion of the Seaway,

including its 13 locks. To generate the

revenues needed to operate and

maintain the Seaway, the SLSMC is

authorized to levy tolls and other

charges. The agreement also provides for the SLSMC to

recover additional funds from the government of

Canada to eliminate operating deficits, when required.

The two American locks in the Seaway are operated 

and maintained by the Saint Lawrence Seaway

Development Corporation (SLSDC), a wholly-owned

government corporation within the U.S. Department of

Transportation. The SLSDC is funded through

appropriations from the Harbor Maintenance Trust

Fund, which is the repository for revenues collected

nationwide from harbour maintenance fees.

The Soo Locks on the upper Great Lakes are managed

and operated by the U.S. Army Corps of Engineers. 

Its Great Lakes and Ohio River Division is based in

Cincinnati and has seven districts, three of which (Detroit,

Buffalo and Chicago) cover the American territory

within the Great Lakes basin. Apart from management

of the Soo Locks, USACE has also been given responsi -

bility for water resource projects related to navigation,

flood control, streambank and shore erosion, ecosystem

restoration and protection, and the maintenance of

ports and harbours.

30 Great Lakes St. Lawrence Seaway Study

Chapter 2

Both the Canadian and U.S. coast guard services are

active on the Seaway and in the Great Lakes. Both

coast guards are responsible for buoys, lights, channel

markers and sophisticated electronic positioning systems

used by large commercial vessels. They also undertake

some icebreaking activities on the waterway. The U.S.

Coast Guard is charged with a series of enforcement 

and policing activities in all the coastal waters of the

United States.

Aerial view of the Beauharnois dam and power station, next to the Lower Beauharnois Lock.

Source: The St. Lawrence Seaway Management Corporation
There are many ports in the GLSLS system, ranging

from the very large to the very small. Major ports such

as Montreal, Hamilton or Duluth-Superior handle

millions of metric tons of traffic each year. In addition,

there are smaller ports that handle significant volumes

of traffic as well as ports that specialize in one or a 

few commodities. 

The administration of the ports varies. In the U.S., 

ports may be administered by state authorities or by

independent commercial operations. In Canada, the

ports of the GLSLS system include the commercialized

Canadian port authorities, local port authorities, private

ports and those directly administered by government. 

In addition, facilities within ports may also be public or

private and either specialized or able to handle a wide

variety of cargoes. 

GLSLS infrastructure is also governed by the seasons. 

In winter, ice clogs much of the waterway, closing the

upper portion to navigation. Ice breaking, ice booms and

other ice management activities allow for year-round

shipping from the Port of Montreal out to the Atlantic

Ocean. Above Montreal, in the St. Lawrence Seaway,

ice breaking and other ice management activities are

often required at various locations both early in the

season and near its end, depending upon the severity of

the winter and its related ice conditions. Generally, the

Seaway from Montreal through to Lake Erie operates on

a nine and a half month season, typically closing at the

end of December and re-opening in March. On the

upper Great Lakes, the Soo Locks generally are open for

approximately ten months of the year. It is during winter

closures of the GLSLS that major maintenance and

rehabilitation are performed on the locks and canals. 

Great Lakes St. Lawrence Seaway Study 31

The Waterway

The complex array of locks, canals, navigational channels

and ports of the GLSLS system operates with a relia -

bility of more than 98 percent. Slowdowns or closures

occur less than 2 percent of the time. Approximately

two-thirds of this downtime is weather-related (poor

visibility, ice, wind). Vessel incidents cause one-quarter

of the downtime. All other causes, including break -

downs, account for the remainder. 

This high level of reliability can be attributed to the

regular ongoing maintenance activities conducted

throughout the system. The annual winter shutdown of

navigation gives work crews an opportunity to conduct

scheduled maintenance of the lock facilities. The lock

systems have experienced minimal physical change over

the past half-century. Inevitably, however, they are

subject to the wear and tear of constant ship passages

and sooner or later, components wear out and must 

be replaced.

EVOLUTION

The GLSLS system achieved its current configuration

with the opening of the St. Lawrence Seaway in 1959

and the re-opening of the rebuilt Poe Lock in 1969. 

The assumptions underlying the development of the

system at that time were relatively straightforward: traffic

in the GLSLS was expected to consist of downbound

grain from Canadian and American ports, and upbound

iron ore moving from the Quebec-Labrador region to

American and Canadian steel mills. This was the core of

the original vision for the GLSLS and it remained valid

for two decades of rapid economic growth. Eventually,

however, this vision was supplanted because of

fundamental shifts in the global economy. 

NON INFRASTRUCTURE SUPPORT FOR THE GLSLS SYSTEM

Beyond the organizations with direct responsibility for the operation and maintenance of system infrastructure, there are numerous

other government or private organizations that provide a variety of important services in the GLSLS system. Key services include: 

• regulation of water levels by the International Joint Commission set up by Canada and the U.S.; 

• customs and immigration services of both governments;

• health inspections by agencies of both governments;

• environmental protection and clean-up by a variety of government agencies;

• oversight of pilotage and navigation services by several pilotage authorities;

• oversight of shipping and carriage by several business associations; and 

• economic development and business representation by organizations such as local chambers of commerce.

The number and diversity of these services reflects the significance and complexity of the system. 
The international marketplace underwent a series of

dramatic transformations in the 1970s and 1980s. 

A revolution in agricultural productivity meant that the

European Union (EU), East European and Russian

demand for grain peaked in the 1970s and declined

thereafter. At the same time, there was a shift in the

focus of grain exports to the markets of Asia. The grain

trade was also weakened by growing international

conflicts over agricultural subsidies. As a result, demand

for grain fell well below original expectations and the

movement of grain through the GLSLS declined 

appreciably.

The decline in grain exports turned out to be a

contributing factor in the observed decline in upbound

iron ore shipments from Quebec-Labrador, since these

had been used as a backhaul complement to the grain

moving in the other direction. But there were other

factors affecting iron ore. The regional and North

American economies shifted away from primary industries

and toward other forms of manufacturing as well as the

service sector. That meant reduced demand for primary

materials such as steel and thus not only a decline in the

steel industry, but in the shipping of ore and coal needed

to sustain that industry. This change was exacerbated by

the dual effects of recession and restructuring, the latter

spurred on by trade liberal ization, which exposed

regional industries to inter national competition. 

The advent of globalization meant radical shifts in

demand, markets and production. East Asia emerged as 

a manufacturing powerhouse, shifting the economic

centre of gravity away from the Atlantic and into the

Pacific. At the same time, the demands of competition

drove the construction of larger oceangoing vessels that

were simply too big to pass through the locks of the

GLSLS system. Finally, general cargo ships were replaced

by container ships that operated on tight schedules 

and made a limited number of calls, thus further trans -

forming the competitive environ ment within which the

GLSLS system operated. 

Another set of fundamental changes occurred in the 

North American domestic transportation industry. The

construction of the GLSLS system was paralleled by the

development of a continental system of multilane

expressways that made trucking the key element in

commercial transportation and induced other transport

modes to link to it. Increasingly, trucking was used when

timelines were short and flexibility was critical. 

As the relationship between the Canadian and

32 Great Lakes St. Lawrence Seaway Study

Chapter 2

American economies developed in the wake of the Auto

Pact, and then free trade, companies on both sides of

the border used trucks to deliver key inputs “just-intime” to subsidiaries or partners. The GLSLS system did

not participate to any great extent in this intense intrafirm and intra-industry cross-border exchange of semifinished and finished manufactured goods. But it has

been indirectly affected by the growing congestion

experienced along the highways that carry this traffic.

Congested highways affect the operations of the GLSLS

ports that link into them, but they also make the

relatively uncongested GLSLS an appealing alternative

for certain types of traffic. 

Finally, it should be noted that in the 1960s, environ -

mental issues did not carry the same weight that they

have subsequently acquired and little was known about

the potential environmental impacts of the GLSLS

system. Physical changes to the waterway happened, for

Vessel being raised in a lock

Source: The St. Lawrence Seaway Management Corporation
the most part, some 50 to 75 years ago and the aquatic

and nearshore ecosystems have largely adapted to these

new conditions. Some effects, such as water level

regulation, ship wakes, pollution, spill risk and nonindigenous invasive species continue to present

environmental challenges. Such problems are the topics

of extensive ongoing study by scientific and environ -

mental personnel from both the U.S. and Canada. The

findings of these studies are being used to develop new

management strategies for the environmental challenges

posed by commercial navigation. 

The GLSLS system has faced numerous challenges and

changes. Because it has been dominated by bulk

commodity traffic, its evolution reflects the economic

and geographic characteristics and trends of the iron,

coal and grain trades. As a result, usage in the Seaway

portion of the system increased steadily from its opening

in 1959 until 1979, after which traffic began to decline.

Even so, the GLSLS remains vital to several strategically

significant industries in the region. For example, it

remains critical for the region’s steel industry, which in

turn is a major driving force in the overall economy not

just of the Great Lakes basin, but of North America as a

whole. In addition, the GLSLS system has the capacity

to carry twice the volume of its current traffic, an

important potential asset for the future, given growing

congestion on roads and railways in the region.

Great Lakes St. Lawrence Seaway Study 33

The Waterway

CHALLENGES

The changes of the past half-century have presented the

GLSLS with four distinct but interrelated challenges

that form the basis of this study. 

The first of these challenges is to determine what role

the GLSLS should play within a highly integrated 

North American transportation system. The answer to

that involves an analysis of markets and products to

determine what goods can benefit the most from the

transportation services offered by the GLSLS (see

chapter 3). It involves an analysis of alternative modes

of transportation to determine where the GLSLS enjoys

a competitive advantage. And it includes a review of the

continental transportation grid to determine how best

the GLSLS can take advantage of multimodal linkages

and opportunities (see chapter 6).

When moving goods from one point to another, marine

transportation usually cannot cover the entire route

from original source to final consumer. As a result, it

needs to link to rail and road transport modes. The

availability, efficiency and costs of such intermodal

linkages determine when marine transportation is used

by shippers. Increasing road and rail congestion in the

Great Lakes basin presents an opportunity to off-load

some traffic onto the marine sector; however, this

opportunity is also constrained by the availability and

efficiency of multimodal linkages.

The demographic shift toward increasing urbanization

over the past 50 years has strained highway systems and

there is now a widely acknowledged need to re-invest in

transportation infrastructure. Left unchecked, congestion

of North America’s rail and highway systems may become

a limiting factor in economic growth. Consequently, the

ongoing operation of the GLSLS is essential to avoid

transfer of its current cargo mix to already congested rail

and highway networks. Moreover, the surplus capacity

that exists in the GLSLS could provide significant relief

to these other transportation networks.

The second challenge facing the GLSLS system is to

keep up with changes in the transportation industry and

the technologies that drive change in order to guarantee

a dynamic future for the industry. 

Two lakers passing in the St. Clair River, Michigan

Source: U.S. Army Corps of Engineers
Over the past few decades, the railways have introduced

significant improvements, especially to their container

services. For example, significant enhancements have

been made to “through services” from Montreal and

Halifax, and new container lines are now serving ports

on the U.S. East Coast, including the Port of New York/

New Jersey and the Port of Norfolk, Virginia. There is

also continuous upgrading of highways in the region,

though road improvements in urban areas confer little

benefit on the trucking industry, since they are quickly

absorbed by rapidly growing volumes of commuter traffic.

Finally, coastal seaports in the U.S. are increasingly

experiencing capacity constraints because they lack

space and ground transportation infrastructure.

Set against these changes are new types of vessels that 

can enhance the competitiveness of the GLSLS system

vis-à-vis other transportation modes. Faster vessels,

container ships and self-unloading carriers are examples

of new technological solutions that can restore the

competitiveness of the GLSLS system. This issue is dealt

with extensively in chapter 6 of this document. 

The third challenge facing the GLSLS system is to

optimize the many different components of the system’s

infrastructure, maintaining its operational viability in

the face of the inevitable processes of wear and aging.

Thousands of passages through the system’s locks have

left their mark on the components of the system. If the

system is to continue to serve the industries of the

region while providing an alternative to congestion in

land-based transportation, then its components must 

be refurbished or replaced, ideally before they fail and

interrupt traffic. The analysis of system components

summarized in chapter 5 constitutes the basis of

recommendations for a strategy for anticipating and

mitigating such failures. 

34 Great Lakes St. Lawrence Seaway Study

Chapter 2

The final challenge is to sustain the operations of the

GLSLS system in a way that responds to concerns about

environmental integrity. Chapter 4 summarizes the key

concerns about the impact of the GLSLS system on the

region’s environment. It is clear from this analysis that

navigation is only one of the factors at play. The region

in which the GLSLS system is situated is home to threefifths of the Canadian population and one-fifth of the

American population. There are also five major urban

centers in the Great Lakes basin and St. Lawrence

River. The diverse activities typical of these urban

agglomerations have a profound effect on air, water and

soil quality. As North America’s industrial heartland,

the region inevitably affects a variety of environmental

features. Even the recreational activities that gravitate

to the Great Lakes are responsible for their own set of

impacts. The additional environmental stresses imposed

by commercial navigation contribute to the cumulative

environmental impact of human activities within the

Great Lakes basin and St. Lawrence River, but they are

only one of the factors at play. 

The GLSLS region retains its role as a major manu -

facturing hub by continuing to maintain and improve its

transportation infrastructure and service levels to focus

on responsiveness, punctuality and reliability. It is an

integral part of a major international, multimodal

transportation network. In the case of many major

mature industries, their goods and commodities flow

from ship to rail and truck, and from rail and truck to

ship in well-synchronized trade patterns. And for all

industries in the region, the traffic that continues to flow

through the GLSLS shows that the system continues to

be a tremendous economic asset that must be renewed

and maintained. 

FOUR FUNDAMENTAL CHALLENGES

What role should the GLSLS system play within the highly

integrated North American transportation system?

What transportation solutions are available to guarantee 

a dynamic future for the waterway?

What measures need to be taken to optimize the many 

different components of the system’s infrastructure? 

How should the GLSLS system sustain its operations in 

a way that responds to concerns about environmental 

integrity?
CHAPTER 3

The Economic Importance of the GLSLS

The Great Lakes St. Lawrence Seaway system continues 

to play a decisive role in the economic life of North America. 

The nature and size of the traffic passing through it remains imposing.

Moreover, much of this traffic serves industries with specialized 

needs that make them highly dependent on the availability 

of cost-effective waterborne transportation. 

These industries are integrated into value chains stretching into

virtually every sector of the North American economy, 

thus giving the traffic moved on the waterway a strategic 

significance beyond its already considerable dimensions. 

What is more, those volumes will experience moderate 

growth in coming decades, reinforcing the system’s value 

to the North American economy. 
The fate of the Great Lakes St. Lawrence Seaway

(GLSLS) ultimately depends on the economic role that

the system plays now and in the future. The size,

significance, frequency, and nature of the traffic using

the system will determine the type of maintenance

strategy that is most appropriate for the needs of the

GLSLS. 

Recognizing this, the Economic Working Group of 

the GLSLS Study examined the size and nature of the

traffic that has used the system since the middle of the

20th century, looking at changes in its cargo mix and

direction. It then used a variety of models to project the

kind of traffic that might be expected in the GLSLS

over the coming half century. In developing these

models, the working group examined both the internal

dynamics of the system as well as foreseeable external

trends likely to influence that traffic. Ultimately, the

purpose of this part of the study was to define the

economic significance of the GLSLS as input into the

exercise of determining the infrastructure that will be

needed to support that economic activity. 

EVALUATING

SIGNIFICANCE

In evaluating the economic significance, the study

considered the size and scale of the traffic that flows

through the GLSLS today. 

On the Canadian side, half of

Canada’s 20 largest ports are part

of the system. On average, these

ports handle approximately 

55 million metric tons (Mt) or

40 percent of Canada’s total

domestic marine trade by volume

and close to 60 Mt or 50 percent

of Canada’s total transborder

trade by volume with the United

States (U.S.). With respect to

American domestic marine

trade, more than 100 Mt is

moved internally between ports

on the system. This accounts for

about 10 percent of all U.S.

waterborne domestic traffic. 

36 Great Lakes St. Lawrence Seaway Study

The true importance of the GLSLS, however, rests with

the nature of its traffic: the prosperity of several sectors

depends on the system. These include iron and steel,

cement manufacturing, energy production, and agricul -

tural exports. All of these industries depend on the

availability of reliable, low-cost waterborne transportation.

For example, the North American steel industry is

clustered around the perimeter of the Great Lakes, as is

the automotive industry that depends on it. Similarly,

coal-fired electrical plants stretch along the shores of the

Great Lakes, which offer a highly cost-effective way of

providing them with the fuel they need.

In these cases and others, the GLSLS plays a vital role as

a transportation corridor, providing indus try with raw

material inputs or offering a convenient and costeffective way of exporting their outputs. In that sense,

the GLSLS is the foundation of economic activity that

has a multiplier effect throughout North America.

There are several ways of describing the traffic that

moves through the waterway. The most fundamental of

these is to look at the types of cargoes carried in the

system. In addition, however, it is also possible to

develop important insights by looking at the individual

segments of the system or by considering origins and

destinations of traffic. The study considered each of

these in turn. 

Chapter 3

Chicago, Kenosha, 

Lake County, 

Gary-Hammond 

Grand 

Rapids, 

Muskegon 

Flint, SaginawBay City-Midland 

Benton Harbor, 

Kalamazoo 

Elkhart, Goshen, 

South Bend-Mishawaka 

Milwaukee, Racine 

Thunder Bay 

Duluth 

Appleton-Oshkosh-Neenah, 

Green Bay, Sheboygan 

Cleveland, 

Akron, 

Lorain-Elyria 

Toledo 

Fort Wayne Lima 

Toronto 

Oshawa 

Erie 

London 

Hamilton St. Catharines, 

Niagara Falls 

Rochester 

Syracuse 

Buffalo, 

Niagara Falls Kithener 

Sudbury 

Windsor 

Montreal Sorel-Tracy 

Trois-Rivières 

Becancour

Québec 

Baie-Comeau 

Rimouski 

Port-Cartier 

Sept-Îles 

Detroit, 

Ann Arbor 

Battle Creek, 

Jackson, LansingEast Lansing 

FIGURE 3.1

Main industrial centres of the GLSLS system’s region
CARGOES

The commerce passing through the GLSLS today can be

grouped into six broad cargo categories: grain, iron ore,

coal, steel, stone and all other commodities. A separate

feature of GLSLS traffic is containerized cargo (mostly

concentrated at the Port of Montreal), carrying a wide

variety of goods. 

Grain

The possibility of strengthening North American agri -

culture by exporting grain internationally was a key factor

driving the original construction of the St. Lawrence

Seaway. To this day, grain originating on the Canadian

and American prairies is moved by rail to Thunder Bay,

Ontario and Duluth, Minnesota, from where it is loaded

either onto lakers that move it to ports on the lower 

St. Lawrence for further transhipment, or onto oceangoing vessels for direct export overseas. A small portion

of the grain is dropped off at various ports along the

GLSLS. In recent years, grain produced in Ontario has

started playing a somewhat larger role in the movement

of grain through the Seaway. 

Historical grain traffic through the GLSLS peaked in

the late 1970s and early 1980s. Subsequent market and

structural changes have reoriented shipping patterns in

this industry. Over 1998-2003, the GLSLS carried 

12.5 Mt per year of grain, which amounted to approxi -

mately 10 percent of the combined total of all U.S. 

and Canadian grain exports. The GLSLS accounted for

about 30 percent of Canadian grain exports, but only 

two percent of the total American grain exports, which

overwhelmingly tend to move down the Mississippi and

out through the Gulf of Mexico. Even so, the GLSLS

continues to be a significant factor in maintaining

North American agriculture. 

Great Lakes St. Lawrence Seaway Study 37

Determinants of grain traffic: Canadian grain traffic

through the GLSLS is influenced primarily by changes

in demand for grain in traditional markets in Europe,

North Africa and the Middle East, Latin America, the

U.S., other African countries and the former Soviet

Union. Two key factors in this regard were the softening

of demand for imported grain in Western Europe as a

result of the European Union’s common agricultural

policy and the disappearance of demand for foreign grain

in the former Soviet Union after 1993.

Beside these demand factors, the size of the grain move -

ments via the waterway depends on the availability of

alternative modes of transportation that offer competitive

total costs and charges. In recent years, technological

and legislative developments in Canadian grain

transportation and handling systems have made it more

cost-effective to move Canadian grain directly by rail

from the Prairies to Quebec and American markets. 

The development of grain exports through the ports of

the Pacific seaboard has also affected the proportion 

of Canadian grain exported via the GLSLS. 

Most of the U.S. grain exported through the GLSLS is

destined for Western Europe. In 1988, only 14 percent

of U.S. grain exports to Europe moved through the

GLSLS, but by 2004 this share had risen to 45 percent.

This is, however, a larger proportion of a declining base:

total American grain exports to Western Europe have

declined from 12.7 Mt in 1988 to 4.9 Mt in 2004, which

means that the absolute volume of American grain

moving through the GLSLS has fallen. The GLSLS does

play an important role as a safety valve, however. In

years when the American grain transportation system

reached limits on capacity, the GLSLS was able to

The Economic Importance of the GLSLS

Milwaukee 

Thunder Bay 

Duluth 

Burns Harbor Toledo 

Owen Sound 

Goderich 

Sarnia 

Hamilton 

Buffalo 

Port Colborne 

Port Stanley 

Montreal 

Prescott 

Québec 

 Windsor 

FIGURE 3.2

Grain trade patterns

Grain terminal in Montreal, Quebec

Source: Port of Montreal, Quebec
accommodate the overflow. This has happened on

several occasions, most recently in the aftermath of

hurricanes Katrina and Rita in 2005. 

The movement of grain through the GLSLS is influenced

by broader changes in grain handling and transportation

occurring at the continental level. Western Canada has

experienced increasing commercialization of the statutory

rail freight rate structure, closure of branch lines and

country elevators, and the growth of large inland terminals.

In the East, the railways have captured some of the grain

traffic that lakers used to carry to the milling industries

of Ontario and Quebec. This happened because the

railways are able to supply smaller quantities at frequent

intervals, saving millers from having to store boatload

quantities of grain in elevators. The same preference for

convenience is also being reflected in the increasing

containerization of export grain, since millers and

processors prefer to receive shipments in quantities that

are easier to handle.

Rail transportation from the Prairies directly to Quebec

City is a cost competitive alternative to the GLSLS,

especially in the winter months when the latter is closed.

However, given the large volumes of grain that move

through the eastern transfer elevators, marine transportation should continue to predominate, especially since

not all elevators are accessible by rail. Grain is also

shipped by ocean-going vessels from Thunder Bay

directly to overseas destinations at costs that are almost

exactly comparable to moving the grain by rail from

Brandon, Manitoba to Quebec City and then by ship.

Since grain is often sold where it is available, the

options of shipping direct from Thunder Bay or from a

transfer elevator in the St. Lawrence River have

additional advantages that are not reflected in a simple

analysis of transport and handling costs.

Inputs to the iron and steel

industries

The second major group of com modities passing through

the GLSLS consists of inputs to the steel industry. The

group includes iron ore, metalurgic coal and coke and

limestone – all used in the production of steel. 

Iron ore: In terms of raw tonnage, iron ore accounts for

a larger propor tion of GLSLS shipments than any other

commodity. In 2004, about 40 percent of the tonnage

carried through the GLSLS consisted of 103 Mt of iron

ore from local sources. 

38 Great Lakes St. Lawrence Seaway Study

Ore from the Mesabi Range was shipped by laker via

Duluth, Minnesota and Superior, Wisconsin and from

Marquette, Michigan on Lake Superior. Most of it

passed through the Soo Locks to steel mills in Illinois,

Indiana, Michigan, Ohio and Ontario. In addition, 

ore from the Marquette Range was shipped through

Escanaba, Michigan on the shores of Lake Michigan. 

In 2004, the mines of the Labrador Trough in Quebec

produced some 28 Mt of iron ore. Of this total, more

than 11 Mt, about 40 percent, was sent upstream

through the Montreal-Lake Ontario (MLO) section of

the GLSLS with 5.5 Mt destined for Canadian steel

mills and 6.1 Mt for the U.S. The remaining iron ore

from the Labrador Trough was exported, primarily to

Germany and the United Kingdom. 

Metallurgical coal and coke: The major steel producers

in Indiana, Illinois, Ohio and Ontario all use metallur -

gical coal. In addition, coke, which is derived from coal,

is used in firing steel mill blast furnaces to provide the

carbon and heat required to reduce iron ore to molten

pig iron. Coke is also consumed to a lesser degree by the

cement and aluminum industries. Most coke traffic is

downbound, originating in the U.S. and moving to

Canadian destinations for local consumption or for transhipment overseas. Major American ports of origin include

Detroit, Duluth-Superior, Cleveland and Buffalo.

The major overseas sources of coke are European,

particularly Italy and Spain. Since coke is integral to the

iron and steel industry, fluctuations in coke traffic

through the GLSLS follow fluctuations in the iron ore

and steel industries as well as changes in the avail ability

of Canadian domestic supplies. 

Chapter 3

Duluth 

Superior Presque Isle 

Escanaba 

Indiana Harbor 

Silver Bay 

Two Harbors 

Burns Harbor 

Gary Toledo 

Eastern Trade Flows Western Trade Flows 

Hamilton 

Sept-Îles 

Port Cartier 

 

Conneaut 

Cleveland 

Taconite Harbor 

Nanticoke 

FIGURE 3.3

Iron ore trade patterns
Limestone: The producers of iron and steel also 

depend on supplies of limestone, which is used as an

agent that reacts with and removes impurities during the

pro duction process. See the section below on stone for

details about the position of limestone in GLSLS traffic

analysis. 

Iron and steel: The iron and steel passing through the

GLSLS is imported from abroad and destined for

Canadian and American ports on the Great Lakes. 

The volume of foreign, unfinished steel (e.g., slab) is

overshadowed by the much larger volumes of finished

steel (e.g., coil). Slab is generally destined for Hamilton

and several U.S. Lakes ports including Toledo, Detroit

and Burns Harbor. A small amount of American and

Canadian steel moves through the Seaway for export

overseas but the bulk of the region’s steel production is

consumed in local markets. The Seaway transports a

small amount of steel passing between the U.S. and

Canada, as well as steel moving within Canadian or

American domestic markets. The volumes of steel

shipments fluctuate in accordance with the health of the

economy, which has a direct impact on American steel

mills in particular. 

Determinants of traffic: Ultimately, shipments of this

commodity group depend on the demand for steel

within the areas served by the GLSLS. Because these

commodities constitute the core of the iron and steel

industry, shipment volumes are heavily influenced by

macroeconomic considerations and technological

change as well as by the economic performance of the

steel manufacturing and automotive industries that are

the cornerstone of the entire region.

There have been several waves of restructuring in the

North American steel industry over the past 20 years.

This has resulted in fewer, but financially stronger,

companies. Since 2004, the world economy, and China’s

economy in particular, have experienced strong economic

growth. This has been associated with stronger demand

Great Lakes St. Lawrence Seaway Study 39

for steel: North American steel usage has increased by

almost four percent per annum between 1990 and 2003. 

As a result, world steel prices have risen. At the same

time, increases in the costs of energy and raw materials

have been offset by improved labour efficiency. The end

result has been a more profitable industry that has the

means to invest in new technologies associated with

more efficient steel making as well as reduced environ -

mental impacts. The industry is now producing new

lightweight and high-strength steels, using less energy

than before. 

A variety of technological developments will strengthen

the long-term sustainability of the industry but they also

exert a decisive influence on related traffic through the

GLSLS. In some cases, that influence actually diminishes

traffic flows. For example, the growing use of electric 

arc furnace technology has made it economically feasible

to reuse scrap metal more efficiently: approximately 

51 percent of the iron now used to make steel comes

from scrap, and this reduces overall demand for iron ore.

The result is a reduction in iron ore shipments through

the GLSLS. 

Tending in the other direction, however are improve -

ments in the capacity and efficiency of regional steel

production as compared to international sources. These

drive increases in GLSLS traffic. One example of this is

offered by emerging techniques for converting ore to

finished steel. Prior to the 1950s, the iron ore produced

north of Lake Superior was high-grade hematite ore,

typically with an iron content of 50 percent. As these

deposits were depleted, production fell. In the 1950s,

new techniques emerged for extracting and refining the

region’s abundant deposits of lower grade taconite ore,

which has an iron content of 25-30 percent. The resulting

marble-sized taconite pellets have an iron content of 

60-65 percent. This new mining technology revitalized

the production of ore from the Mesabi Range, which is

now the mainstay of modern ore traffic in the GLSLS:

approximately 95 percent of all ore shipped in the

system is now pelletized. 

New technologies are also being developed to produce

iron nuggets using coal as a reduction agent in a rotary

hearth furnace. If proven at the pilot-plant scale, this

new technology could allow large-scale production of

nuggets with an iron content of 97 percent. This could

lead to significant energy savings and emission reductions

in the steel making process, and could allow steel makers

to use this processed ore directly in basic oxygen steel

furnaces or electric arc furnaces. Such emerging tech -

nologies may serve as the foundation for a highly efficient

third wave of steel making that could revitalize and

sustain steel making within the Great Lakes basin.

The Economic Importance of the GLSLS

Milwaukee

Marinette

Chicago

Duluth

Burns 

Harbor Toledo

Detroit Hamilton

Oshawa

Toronto

Ashtabula

Windsor

Cleveland

FIGURE 3.4

Iron and steel trade patterns
Such technological developments will strengthen traffic

through the GLSLS. Beyond technology, however, there

are other drivers. For example, the imposition of American

tariffs on steel imports from March 2002 to December 2003

significantly reduced the amount of foreign steel moving

through the Seaway during the 2002 and 2003 navi -

gation seasons. 

Ultimately, the volume of steel industry inputs passing

through the GLSLS depends on both the competitive -

ness of local producers vis-à-vis international competitors,

and the competitiveness of the GLSLS transportation

system vis-à-vis alternative modes and routes.

In terms of industry competitiveness, local producers are

holding their own. For example, Canadian producers of

iron ore remain competitive as suppliers to the iron and

steel industries on the shores of Lake Ontario, Lake Erie,

Lake Michigan and the American eastern seaboard.

Their competitiveness, however, diminishes as their

distance to other markets increases. High transportation

costs make them less competitive on the American Gulf

Coast and in Europe. In 2004, 4 Mt of Quebec-Labrador

iron ores were exported to Asia, as compared to 2.8 Mt a

decade ago. This is because Asian clients are willing to

offer preferential transportation rates on their vessels.

However, any combination of a stronger Canadian

dollar, higher freight rates on the St. Lawrence Seaway

and/or higher energy costs could significantly reduce the

cost-competitiveness of local iron ore producers.

The competitiveness of the GLSLS as a transportation

system is reflected in factors such as locational advantages

and transportation charges. The iron and steel industry

arose in the Great Lakes basin because of the availability

of low-cost waterborne transportation suitable for the

movement of large volumes of bulk commodities. The

volumes transported, however, fell in the early 1980s

because of significant restructuring within the industry.

Those volumes have now recovered as new technologies

have come on line: they have been rising since about

2001 and are expected to continue doing so. As long as

the iron and steel industry prospers in its current location,

there will be an ongoing demand for transportation

through the GLSLS. That is because it is unlikely that

the huge volumes of iron ore or coal driving this industry

can be shipped cost-effectively or expeditiously over the

already congested rail or highway routes in the region. 

Coal

Most of the coal passing through the GLSLS is destined

not for the steel industry but for power generation. In 2004,

the system carried 37.5 Mt of coal worth approxi mately

$1.7 billion. Of this total, 94 percent was destined for

power generation and only 6 percent was in the form of

coke for the steel industry. 

40 Great Lakes St. Lawrence Seaway Study

Local power plants are especially interested in the 

low-sulphur coal from the Powder River Basin stretching

across southeast Montana and northeast Wyoming. 

Coal from this region is transported by train to Superior,

Wisconsin, where it is loaded aboard lakers that deliver

it to electrical generating stations along the shores of

the lower Great Lakes. One of the largest consumers of

this coal is Michigan’s Detroit Edison, which annually

tranships approxi mately 20 Mt of coal through the port

at Superior. 

In addition, there is coal originating in Kentucky and

West Virginia that is shipped from Chicago and from

Lake Erie ports such as Ashtabula, Ohio. In fact, Ohio

has emerged as the second largest transit point for coal

shipments in the GLSLS. In 2004, it accounted for

shipments of 20 Mt, 79 percent of which was destined

for Ontario. Because it has no coal sources of its own,

Ontario imports a total of about 21 Mt of coal a year

Chapter 3

Midwest Energy terminal in Superior, Wisconsin

Photo: http://www.midwestenergy.com

The Midwest Energy Resources Company coal transhipment

facility at the port of Superior was opened in 1976 at a cost

of $45 million. After completing the 1,100 mile journey 

from the Powder River Basin in Wyoming, trains carrying

13,200 metric tons of coal are discharged at the port facility

in about 3.5 hours by the world’s fastest single-car rotary

unloader. The coal is then loaded aboard lakers at an average

rate of 8,000 metric tons per hour.
(about 95 percent of all coal imported into Canada).

Approximately 17 Mt of the coal imported by Ontario is

consumed in power generation, 3-4 Mt is used in steel

production and a small amount goes to other industries.

Determinants of coal traffic: Coal traffic through the

Soo Locks and on the Upper Great Lakes has been

driven by the availability of low sulphur coal from the

Powder River Basin. At the port of Duluth-Superior,

shipments have been growing steadily to the

point that in 2005, volumes of coal (19 Mt)

exceeded volumes of iron ore (17 Mt) for the first

time in history. In the Seaway portion of the GLSLS

system, coal shipments recovered after the closure of

several Ontario nuclear generating plants increased

demand for thermal coal in the late 1990s. 

Coal shipments through the GLSLS have changed

significantly over the past 50 years. Shipments

through the MLO and Welland Canal have

tended to be stable while shipments through the

Soo Locks have risen significantly. The three lock

systems, however do not encompass all of the coal

shipped through the system traffic, since some of

it moves through the lakes without passing any

locks. Overall, however, the upward trend in coal

shipments has been unmistakable. The system has

adapted to these additional volumes by developing port

facilities on Lake Superior capable of loading coal onto

lakers at an average rate of 8,000 metric tons per hour. 

The growth of coal traffic in the GLSLS and the

system’s ability to accommodate additional volumes

shows that it remains competitive for this commodity. 

It is possible to move coal by rail and continued

improvement in railway efficiency, especially the

deployment of higher capacity freight cars and new

locomotives, has meant that direct rail transport can be

less expensive than a combined rail-laker routing. The

use of higher-capacity ships, however, has helped to keep

Great Lakes St. Lawrence Seaway Study 41

this cost differential relatively small. In addition, marine

transport through the GLSLS offers coal shippers the use

of self-unloading lakers, a significant advantage over the

need to develop facilities for unloading unit train loads

of coal at the final destination.

Stone

There are two categories of stone cargo moving through

the GLSLS system: limestone is used for its chemical

properties in a variety of industries while other types of

stone are used primarily in construction. 

The market for limestone illustrates the interrelationships

among the various commodities shipped through the

GLSLS. Limestone has long been used in the steel

industry, cement production and construction. However

there is growing demand for limestone coming from

coal-burning industries since it serves as an important

reagent for the reduction of sulphur emissions through

the use of scrubbers and fluidized bed combustion

systems. As a result, growing demand for coal, coupled

with more stringent emission standards for coal-burning

facilities, has strengthened the demand for limestone. 

Most of the traffic in other types of Canadian and

American stone is upbound through the Welland Canal

and the Soo Locks. Downbound traffic moves from

Canada and the U.S. through both sections of the Seaway

to Canadian destinations. Because this stone is used in

producing concrete and in highway construction, traffic

volumes are affected by supply and demand factors

determined by the general economic situation. 

The Economic Importance of the GLSLS

Milwaukee

Chicago

Duluth

Toledo

Monroe

Sandusky

Detroit

St. Clair Sarnia

Muskegon

Superior

Presque Isle

Nanticoke

Ashtabula

Conneaut

Hamilton

Montreal

Windsor

Courtright

Taconite Harbor

Thunder Bay

FIGURE 3.5

Coal trade patterns

Duluth 

 

Superior 

Presque Isle Alpena 

Calcite 

Saginaw 

Kellys Island Fairport Harbor 

Toronto

Hamilton

Montreal

Port-Cartier

Quebec

Cleveland Marblehead Lorain 

FIGURE 3.6

Stone trade patterns
Other cargoes

The last major cargo grouping in the GLSLS consists 

of commodities such as petroleum products, chemicals,

salt and cement. Common to them all is that consump -

tion patterns and, therefore traffic volumes through the

GLSLS, are determined by largely local demand. To take

one example, the amount of salt shipped through the

GLSLS in any given year is influenced by the severity 

of local winters and thus the need for salt on local

highways. 

Petroleum products: This category includes commodities

such as crude oil as well as refined products such as

gasoline and fuel oil. Refineries in Quebec import their

crude oil requirements by tanker, while those located

upstream of Montreal are generally supplied by pipelines,

though this is supplemented by some imports carried on

tankers. Between 1995 and 2003, traffic in petroleum

products through the St. Lawrence ship channel grew by

almost 20 percent to 20.6 Mt., driven largely by the

increasing quantities of crude oil imported to the SaintRomuald refinery in Quebec. 

Almost all of the traffic in petroleum products between

Montreal and Lake Erie originates in Canada and moves

through the Seaway to Canadian and American

destinations. Major Canadian ports of origin are Sarnia,

Nanticoke and Montreal. Important destinations

include Quebec City, Montreal, Cornwall and American

coastal ports in New England. Across the border, some

60 percent of American petroleum product traffic

originates in Indiana Harbor and is distributed to ports

on lakes Michigan, Huron and Erie.

Chemicals: As a category, chemical products are more

diverse than any other commodity group. This is mainly

because they are used in a broad range of industries

including automotive, metals, housing, fertilizers, plastics

and glass. Chemical cargo tends to be downbound

through both parts of the Seaway, moving from Canadian

producers to destinations in Canada, the U.S. and overseas.

Upbound flows are mainly from overseas to the U.S. as

well as from Canadian and U.S. sources to other parts of

Canada. Overseas cargo accounts for major variations

from year to year. Major ports of origin include Sarnia

and Windsor in Ontario, and Louisiana and Florida in

the U.S. Major destinations include Toledo, Hamilton,

Montreal, Morrisburg, Burns Harbor and Western Europe.

Annual variations in Seaway chemicals traffic can be

related to fluctuations in the business cycles of industries

served and to the highly competitive nature of the

chemical industry worldwide. 

42 Great Lakes St. Lawrence Seaway Study

Salt: The salt transported through the Seaway is mined

mostly in the Goderich and Windsor areas of Ontario

and shipped to several Ontario, Quebec and American

destinations. Most of the salt traffic is downbound 

from Canadian and American origins to Canadian

destinations. Salt is used to control ice on highways 

and to a lesser degree in the food processing industry.

Annual variations reflect winter severity and growth in

the demand for salt is related to the expansion and

upgrading of road networks. 

Cement: Cement tends to be upbound from Canada to

the U.S. through the Welland Canal. Ontario dominates

Canada’s cement industry. Cross-border trade in cement

varies considerably from year to year according to demand.

Annual exports of cement to the U.S. amount to 3-4 Mt

and account for about one-third of total Canadian

production. Cement exports are mainly destined for the

southern Great Lakes region and the northwestern

Pacific region. Canada imports about 0.5 Mt of cement

each year, primarily as part of cross-border regional

trade. Cement traffic on the Seaway is affected by supply

and demand as well as the overall economic situation.

After some years of initial growth, total traffic in these

varied commodities has reached a point of stability.

Some products in some segments of the system display

marginal long-term growth: this is the case with salt and

cement moving through the Welland Canal over the

past three decades. Other products in other segments

display trends moving in the opposite direction: shipments

of petroleum products through the MLO section have

contracted from 3.5 Mt in 1970 to only 1.4 Mt in 2004.

Despite such variation, overall traffic remains stable. On

both the Welland Canal and the MLO sections, annual

non-grain, non-ore traffic has averaged just over 13 Mt

since 1965 and traffic in individual years has not varied

from that average by more than 3 Mt. 

Chapter 3

Self unloader laker vessel unloading limestone 

Source: U.S. Army Corps of Engineers
Emerging cargo movements: The bulk commodities

traditionally carried through the GLSLS system have

recently been augmented by new and diversified types of

cargo movements. While the tonnages of these new

cargoes remain relatively small, as a category, they reflect

niche markets where marine transportation provides

either direct, bottom-line benefits or serves as an

efficiency-enhancing complement to surface transpor -

tation. The movement of aluminum ingots between

Sept-Îles and Trois-Rivières is a good example of this

new traffic: these shipments move from the St. Lawrence

River to Great Lakes ports such as Oswego, New York

and Toledo, Ohio. Forest products comprise part of the

emerging marine trades along the St. Lawrence River.

There is also growth in highly diversified non-traditional

cargoes such as windmill parts, which are imported from

overseas to inland ports like Hamilton, Ontario and

Duluth, Minnesota, from where they are subsequently

transhipped by truck. These emerging cargo movements

reflect an interest in shortsea shipping as a means to

improve utilization of existing waterway capacity and

facilitate modal integration to help meet the commercial

and socio-economic needs of client industries. 

Containerized cargo

Containerized cargo in the GLSLS is mostly concentrated

at the Port of Montreal. It consists of a wide variety of

products reflecting the industrial mix of Central Canada

and the American Midwest and Northeast. Items such as

forest products, manufactured products, animal, and food

and chemical products, accounted for most of the

international containerized cargo passing through the

Port of Montreal. 

Approximately half of the port’s

containerized cargo traffic has its

point of origin or destination in

the Canadian market, mainly in

Quebec and Ontario. The other

half moves to or from the

American market, mainly the

Midwest (Illinois, Michigan,

Minnesota, Wisconsin and Ohio)

and the Northeast (New England

and New York). Most of this

containerized traffic is transhipped

onto or from rail lines running

inland to and from markets in

Ontario and the American

Midwest.

Great Lakes St. Lawrence Seaway Study 43

In terms of handling containerized cargo, Montreal ranks

5th among the ports of the North American Atlantic

coast. Its hinterland consists of the most heavily industri -

alized region on the continent and huge manu facturing

centres are found along the water, road and rail lines

connecting to Montreal. Between 1993 and 2003, the

general expansion in global trade contributed to a sharp

worldwide growth in containerization. As a result,

container traffic at the Port of Montreal grew from 

0.57 million twenty-foot equivalent units (TEU) in

1994 to 1.11 million TEUs in 2003, an average annual

growth rate of 7.6 percent. 

Western Europe is by far the most important overseas

market for the Port of Montreal’s containerized cargo

exports. In 2003, these exports totalled 4.2 Mt or 

98 percent of all containerized cargo exports handled at

the port. The port accounted for 34 percent of all

container exports to Western Europe from the North

American Atlantic coast.

Western Europe is also the most important overseas

source of containerized cargo imports through the Port

of Montreal. In 2003, Montreal’s imports from this

market totalled 4.9 Mt, or 98 percent of its total inbound

containerized cargo. This accounted for 24 percent 

of all North American Atlantic coast imports from

Western Europe. 

The Economic Importance of the GLSLS

Vessel unloading containers at the Port of Montreal

Source: Transport Canada
SYSTEM SEGMENTS

The three clusters of locks in the GLSLS define three

distinct segments in the system: the Soo Locks sit

athwart the traffic of the upper Great Lakes, the

Welland Canal controls the passage of goods between

the upper lakes and Lake Ontario, while the locks of the

MLO section support traffic between the St. Lawrence

ship channel and the Great Lakes. 

It is important to remember, however, that the size of

the locks determines the dimensions of the traffic. 

The relatively small locks of the Welland Canal and 

the MLO segments do not support the same scale of

domestic bulk cargo traffic as do the much larger Soo

Locks. Furthermore, because both the Welland Canal

and the MLO section carry a significant amount of

ocean going traffic, they are generally more sensitive to

global economic trends. 

Between 1995 and 2003, total cargo traffic through the

GLSLS averaged 261 Mt annually. Of this, some 69 Mt

passed through the Soo Locks, while the Welland 

Canal and MLO section saw about 37 Mt, and 35 Mt,

respectively. Much of the traffic was internal, meaning

that it was loaded and unloaded within the GLSLS

system: the total tonnage handled by all of the ports of

the GLSLS was about 440 Mt.

As Figure 3.7 shows, about 26 percent (76 Mt) of cargo

traffic in the GLSLS originates and terminates in the

lower St. Lawrence River and thus involves no lock

passages. A further 27 percent is internal traffic, which

originates and terminates within the Great Lakes 

(e.g., traffic on lakes Michigan, Huron and Erie), again

without any lock passages. Taken together, the three

lock systems at the Soo, Welland and MLO account for

about 47 percent of total GLSLS cargo traffic, an

average of about 108 Mt per year (based on 1995-2003

statistics).1

Another way of looking at traffic through the GLSLS is

by commodity groupings. Figure 3.8 represents total

average annual tonnages for the six basic cargo groups 

in the system in the period between 1995 and 2004.

Iron ore and concentrates accounted for approximately

40 percent of total volumes and stone was second with

44 Great Lakes St. Lawrence Seaway Study

about 20 percent. Coal accounted for 15 percent of the

total, grain – 7 percent, steel – 3 percent and all other

cargo for 17 percent. Shipments of cargo are essentially

an internal trade, since the overwhelming proportion of

this cargo remains within the system. By contrast, steel

tends to reflect imports of various semi-finished steel

products, primarily from Europe.

There is considerable variation in the traffic mix at each

of the three lock systems. Traffic at the Soo Locks is

dominated to an overwhelming extent by ores and ore

concentrates. By contrast, traffic at the Welland Canal

displays a balance among different commodity groups,

while grains and ores feature prominently at the locks of

the MLO. 

Chapter 3

79

76

69

37

35

0 20 40 60 80

Internal Great Lakes

(no locks)

Lower St. Lawrence River

(no locks)

Soo Locks

Welland Canal

Montreal-Lake Ontario

FIGURE 3.7

Average annual tonnage shipped 1995-2003 

(millions of metric tons)

1 Note that this 108 Mt is lower than the sum of the traffic through each of these three lock systems since some of the traffic goes through

more than one lock system.

0 50 100 150 200 250 300 

Iron Ore 

Coal 

Grain 

Steel 

Stone 

All Other 

Total 

103 

37 

17 

8 

51 

45

261 

FIGURE 3.8

Average annual tonnage shipped 1995-2003 

(millions of metric tons)
It is also possible to trace a certain pattern of movement

through the three lock systems of the GLSLS. The 9 Mt

of grain that pass through the Soo Locks on an annual

basis is destined for export, so the same 9 Mt is seen

passing through both the Welland Canal and MLO

section of the Seaway. 

A closer study of the data underlying the figure reveals

that the iron ore and coal trade at the Soo Locks is

downbound, inasmuch as it originates in MinnesotaMichigan and Wyoming, respectively, whereas the iron

ore passing through the MLO section is upbound since it

originates in the Labrador Trough. 

Other determinants of traffic

The GLSLS system’s primary commercial strength is

that it provides low cost transportation to industries 

that move bulk commodities in high volumes. This has

led to the establishment and growth of industries, the

competitiveness of which depends on direct access to

that low cost transportation capability. 

There is also a stability inherent in the transportation

requirements of these businesses. Primary industries 

such as steel mills, cement plants, and sugar and oil

refineries represent significant capital investments. Once

established, they are not likely to move operations

elsewhere. Thus the GLSLS has a captive client base for

a significant portion of its operations. Even though the

sources for certain raw materials such as coal, iron ore,

and coke may change from time to time, both the supply

and the demand sides of the equation depend on low

cost marine transport.

Set against the background of this relatively stable core

business, there are other factors that affect the size and

nature of the traffic that moves through the GLSLS. 

Backhaul opportunities

Certain types of GLSLS traffic are affected by the

availability of suitable backhaul opportunities. It is

fundamental to all modes of transportation that opera -

tional efficiency is optimized when there are full loads

moving in both directions during any trip. This principle

can apply to seemingly unrelated cargoes. For example,

when there is a growth in American imports of steel

through the GLSLS to ports on Lake Erie and Lake

Michigan, there is a corresponding growth in the export

of American grain from Duluth in the other direction,

since grain serves as a backhaul for ocean-going vessels

bringing in the steel. 

Great Lakes St. Lawrence Seaway Study 45

This relationship can also have a negative impact. 

As already noted, shifts in world markets and domestic

production have meant that the GLSLS is no longer

viewed as the main conduit for Canadian grain exports.

More processing and consumption is done on the Prairies,

while ports such as Vancouver and Prince Rupert on 

the Canadian West Coast have emerged as major grain

export centres. As a result, the amount of Canadian

grain available on the Great Lakes has declined over the

past decade. In the absence of this backhaul opportunity,

many smaller trans-oceanic vessels have become more

reluctant to sail into the Great Lakes and that has

resulted in a shortage of trans-oceanic capacity in the

system for moving other types of cargoes. 

Canadian ore remains highly popular due to its quality,

price and proximity. In the past, iron ore was considered

a backhaul for Canadian lakers carrying grain. With the

decline in grain, however, it has emerged as a headhaul

and the most important cargo in the GLSLS system. 

Its seasonal nature does not seem to be an impediment

since, with the exception of the Dofasco steel facility 

at the Canadian port of Hamilton, Ontario, the dock

facilities of all the regional steel mills rely on selfunloading lakers, which are not practical in winter

months when the ore freezes in the vessel’s hopper.

Competition

There are a variety of competitive factors that act as

significant determinants of traffic in the GLSLS.

Alternative routes, different modes of transportation,

rates, availability, and reliability all play a role in

influencing traffic flows. 

The movement of grain in the GLSLS is influenced by

competing alternatives. Besides the GLSLS, Canadian

and American grain is moved via several other routes

and modes of transportation. Rail is used to move

Canadian grain to Canada’s Pacific ports, to the northern

port of Churchill, to the eastern export ports on the

Atlantic and lower St. Lawrence and to the U.S. In the

U.S., grain is transported to the Gulf of Mexico via the

Mississippi barge/rail system, and by rail to Atlantic and

Pacific seaboard outlets. 

Another competitive factor relates to the supply of and

rates charged for ocean going transportation. Because

ocean-going grain carriers operate in a free market, rates

rise and fall according to changes in demand for services

and the supply of vessels. Thus the extent to which the

GLSLS can offer grain exporters available transport and

competitive rates is directly affected by the global

demand for and supply of ships of an appropriate size. 

The Economic Importance of the GLSLS
There is also fierce competition among world ports for

container traffic. On the supply side, shipping lines

continually attempt to augment their operational

efficiency by reducing costs and by attracting larger

volumes of containers. They employ larger ships and

they use routes that involve more efficient ports of call. 

Given such competition, it is important to note that 

the GLSLS enjoys a decisive competitive advantage.

The system has surplus capacity, and it is thus in a

position to absorb additional traffic at a time when

competing modes are feeling the effects of congestion

and constraints on capacity. For example, Canadian

railways are facing significant congestion on the rail

lines from Toronto to the Detroit/Windsor gateway,

while the trucking industry is becoming increasingly

frustrated by traffic congestion in the Greater Toronto

Area and at border crossings between Ontario and the

U.S. As these pressures increase, shippers may be

increasingly interested in shifting some of their cargoes

to waterborne routes. 

Technology

There are two ways in which technology affects GLSLS

traffic. On the one hand, changes in technologies

associated with shipping alter the cost structures and

competitiveness of waterborne transportation. These

effects are discussed in Chapter 6 of this document. 

On the other hand, technological change within the

industries served by the GLSLS can alter the mix of

cargoes supplying these industries. 

Limestone offers an example of how technological change

influences the size and direction of certain classes of

shipments. Limestone quarries produce stone used in

steel making, cement production and construction.

46 Great Lakes St. Lawrence Seaway Study

Cement companies usually own their own quarries from

which they extract their raw materials. Where possible,

these are located on a waterfront and as close to the

cement plant as possible. In this case, demand for

limestone is directly linked to the demand for cement,

which is affected by the general level of public

construction activity and government investment in

public infrastructures. 

On the other hand, the steel industry uses high-grade

limestone in the production of iron ore pellets and, as a

fluxing agent, in the manufacture of steel. In this case,

technological changes in how steel is made could reduce

the need for fluxing limestone over the longer-term. 

A technological change can also affect demand for coke.

It is likely that North American steel producers will

eventually switch from blast furnaces to electric furnaces

or to a pulverized coal injection process which does not

require coke. As a result, the production and carriage of

coke is likely to continue declining. 

Finally, in the case of coal, concerns about the environ -

ment play a decisive role. Currently such concerns have

strengthened the demand for low-sulphur coal and ship -

ments of this through Duluth-Superior have risen rapidly.

Environmental concerns about the use of fossil fuels,

especially as regards the emission of carbon and other

substances, make coal’s longer term future dependent

upon the implementation of carbon capture technologies. 

Forecast based on existing traffic mix

Under current conditions and given observable trends in

market demand and regional transportation patterns, the

volume of traffic through the various parts of the GLSLS

system should experience a slow but steady increase.

Even if nothing else changes, which is to say, even if no

new cargoes or shipping technologies are introduced

into the GLSLS, there will still be a significant amount

of economic activity that will continue to depend on

the GLSLS. Thus the system will be needed to support

that traffic. The following section analyzes this scenario.

It should, however, be seen as a baseline. There is also

the possibility of new cargos and new transportation

technologies being introduced into the GLSLS, which

will raise demand for its services. That possibility is

explored in Chapter 6. 

Forecast methodology

To confirm the assumption that there will at least be a

slow but steady rise in the demand for transport services

through the GLSLS, forecasts were prepared of the

traffic mix expected up to 2020 at the MLO section, the

Chapter 3

Traffic in the Greater Toronto Area

Source: Transport Canada
Welland Canal and the Soo Locks. Using historical data

up to 2003, the forecasts focused only on the existing

cargo and traffic mix and explored three potential

scenarios: pessimistic, most likely and optimistic. 

They also incorporated assumptions about the economic

conditions and other factors that are likely to affect

GLSLS traffic up to 2020. The methodology used in

preparing these forecasts combined both quantitative

and qualitative econometric techniques directed toward

the analysis of markets as well as the region and its

industrial complexes. Each commodity was analyzed

separately and the methodology applied was adjusted to

the specific characteristics of each commodity. 

First, world demand and supply for the major commodities

using the GLSLS were analyzed and projected. Next, the

North American balances between domestic supply and

demand were estimated and the exports, imports and

domestic shipments that could move via the GLSLS were

segregated. The weight of the combined factors that

influence the selection of the mode(s) and route(s) through

which the cargo could move was applied in order to esti -

mate the GLSLS’ share of this movement. Validation and

testing of the equations consisted of running a correlation

of estimates with past movements. More empirical means,

such as smoothing forecasting techniques were used to

extend the traffic forecast from 2020 to 2050. 

It should be added that this forecasting process

incorporated the following assumptions: 

• There will be annual growth rates of 1.1 percent for

the population, 3.3 percent for the economy as a

whole, and 5.9 percent for international trade. These

estimates are based on World Bank global economic

prospects and the International Monetary Fund’s

economic outlook, along with data from Global

Insight and Transport Canada. 

• Liberalization of trade and globalization of business

will continue.

• The American economy will grow at 2.6 percent

(conservative) and 3.0 percent (optimistic) with the

most likely growth rate of 2.8 percent. It assumes the

American industrial production index should grow

between 2.8 percent and 3.8 percent. The Canadian

economy is assumed to grow between 2.3 percent and

2.6 percent, and the Canadian industrial produc tion

index should increase between 2.6 percent and 

3.4 percent. The exchange rate for the Canadian

dollar against the American dollar should average

1.28 fluctuating between 1.27 and 1.29.2

Great Lakes St. Lawrence Seaway Study 47

• Strategic initiatives to enhance the competitive

position of the GLSLS should counterbalance equiv -

alent activities in other modes; and the system’s tolls

and other related costs will not be increased to levels

that could negatively affect GLSLS traffic.

• Fluctuations in Great Lakes water levels will follow

the trends of the past 20 years; there will be no major

strikes or accidents; and there will be no major

political, social or economic disruptions. 

Changes in one or more of these major conditions could

alter the results of this forecast. For example, emerging

world trade blocs could reduce internal trade barriers

while raising external ones, thereby prompting trade

wars between blocs and weakening international trade.

In this case, North American trade would suffer and

patterns of traffic through the GLSLS would change. 

Shifts between the most likely traffic forecast and the

pessimistic forecast could frequently happen during the

forecast period, depending on conditions prevailing at a

certain point in time. The optimistic traffic forecast is the

least likely to occur and represents the maximum traffic

potential currently possible. This forecast could,

however, be useful in evaluating system capacity.

Forecast results

As shown in the Figures 3.9, 3.10 and 3.11, traffic in

bulk commodities through the GLSLS system is

expected to increase gradually through to the year 2030

and to grow steadily for the 20 years thereafter.

The data summarized in Figures 3.12, 3.13 and 3.14

show the forecasted shifts in the mix of existing

commodities expected in the MLO section, Welland

Canal and Soo Locks up to the year 2050. 

Montreal-Lake Ontario section: In the case of the

MLO section, the relative proportion of most cargoes

should remain more or less the same over the coming

decades, with the exception of steel, which is expected

to experience an increase from 9.3 percent to 16 percent

of total tonnage. Grain should continue to be the largest

cargo category moving through the MLO section,

followed by iron ore, other commodities, steel and coal.

The current relative proportions of the various

commodities are not expected to change appreciably. 

The Economic Importance of the GLSLS

2 At the time of printing of this report, the value of the U.S. dollar has declined relative to the Canadian dollar and many other currencies.

Hence, U.S. exports to Canada (and other countries through the Seaway) will rise so long as they stay competitiely lower in price, while

Canadian exports to the U.S. will decline in response to their rising cost in U.S. dollars.
48 Great Lakes St. Lawrence Seaway Study

Welland Canal: The category of “all other” commodities

is expected to assume a slightly greater prominence in the

Welland Canal, moving from 34.5 percent to 38.1 percent

of total tonnage by the year 2050. Similarly, steel tonnage

is expected to rise from 5.6 percent to 10.6 percent, and

grain from 24.5 percent to 29 percent, while coal and

iron ore will become less prominent in the mix.

Soo Locks: In the case of the Soo Locks, iron ore should

continue to be the largest cargo category until about

2030, after which coal traffic is expected to overtake it.

This will reflect increased demand for coal-based energy

as a result of increasing demand for electricity. Iron ore

and coal are expected to reverse their positions at the

Soo Locks by 2050. Coal will rise from 26.6 percent to

41.7 percent of total tonnage, while iron ore will fall

from 52.3 percent to 36.4 percent by 2050. 

It should be noted that the preceding forecasts all

address the traffic that is expected to pass through the

locks of the MLO, the Welland Canal, or the Soo

Locks. There is also a significant volume of traffic that

moves between different ports on the Great Lakes

without ever passing through any one of the lock

systems. It is expected that this traffic will follow the

same general trends as the Soo Locks forecast, since the

commodity mix and market factors influencing these

cargo levels are fairly similar. 

Ultimately, the GLSLS forecast, based on the existing

traffic mix for the three GLSLS system locks indicates

modest, but steady, growth up to 2050. 

The competitiveness of the GLSLS

The trends in cargoes and tonnages summarized in this

chapter reflect the interplay of complex economic

forces. Within this shifting landscape, however, the

competitiveness of the GLSLS system as an alternative

to other modes of transportation always depends on its

reliability and its relative cost.

Reliability

The cargoes shipped through the locks of the GLSLS

system feed a network of industries within the central

portion of the Great Lakes basin and St. Lawrence River

region. The health of these industries depends, in part,

on the extent to which the supply of the raw materials

shipped through the GLSLS remains reliable.

Most of the locks of the GLSLS system are arranged in a

series. There are only two instances (one at the Soo Locks

and one in the Welland Canal) where there are parallel

locks that could provide redundancy in the event that

one of them fails for any reason. In the rest of the

GLSLS, however, the failure of any one lock gate or wall

Chapter 3

Most likely

Pessimistic

Optimistic 5 year running 

average

Year

20

30

40

50

60

70

1960 1970 1980 1990 2000 2010 2020 2030 2040 2050

Annual tonnage, Mt

FIGURE 3.9

Traffic forecast for the Montreal – Lake Ontario section to 2050

Cargo traffic through the MLO section is expected to grow at

average annual rates of 0.1 percent, 0.7 percent and 1.1 percent

under the pessimistic, most likely and optimistic scenarios,

respectively, reaching 33 Mt, 42 Mt, or 51 Mt by 2050.

5 year running 

average

20

30

40

50

60

70

1960 1970 1980 1990 2000 2010 2020 2030 2040 2050

Annual tonnage, Mt

Most likely

Pessimistic

Optimistic

Year

FIGURE 3.10

Traffic forecast for the Welland Canal to 2050

On the Welland Canal, traffic is expected to grow by 0.0 percent, 

0.5 percent and 1.0 percent under the pessimistic, most likely and

optimistic scenarios, respectively, to reach 32 Mt, 42 Mt or 54 Mt

by 2050. Annual tonnage, Mt

Historical

0

20

40

60

80

100

120

140

Most likely

Pessimistic

Optimistic

Year

1960 1970 1980 1990 2000 2010 2020 2030 2040 2050

FIGURE 3.11

Traffic forecast for the Soo Locks to 2050

Traffic at the Soo Locks is more heavily influenced by domestic

rather than global economic trends. It is expected to grow at an

annual rate of 0.3 percent, 0.7 percent and 1.3 percent under the

pessimistic, most likely and optimistic scenarios, respectively,

reaching 91.4 Mt, 107.3 Mt or 131.3 Mt by the year 2050.
can lead to an unscheduled closure of a large part of the

system, and significant economic impacts on the

industries served. In effect, a lock failure at any point

along the system would create a bottleneck that would

halt all traffic until it was resolved. 

Given this reality, it is encouraging to note that the

GLSLS system remains highly dependable. The complex

array of locks, canals, navigational channels and ports of

the GLSLS system operates with a reliability of more

than 98 percent. Slowdowns or closures occur less than

2 percent of the time. Approximately two-thirds of this

downtime is weather-related (poor visibility, ice, wind).

Vessel incidents cause one-quarter of the downtime. 

All other causes, including lock failures, account for 

the remainder. 

Cost

The cost of providing waterway service is a critical

competitive factor. Overall marine transportation costs

include the capital and operating costs of both the

vessels and the system infrastructure. System infrastructure

costs are accounted for in the assessment of alternative

maintenance scenarios as part of the benefit-cost analysis.

Vessel operating costs are imbedded in the existing

transportation rate that shippers pay for waterway

transportation service. The vessel operating cost, or

waterway linehaul cost, is estimated using vessel costing

models which use hourly vessel operating costs specific

to vessel type and commodity together with estimates of

transit times between specific ports of origin and

destination. The ability to measure the effect of changes

in transit time on transit costs is important, because the

level of investment or maintenance in the system affects

transit times. Less reliable systems will result in longer

transit times, which in turn will result in higher vessel

transportation costs. 

Rate analysis and shipper survey

Vessel costs and transportation rates can be used to

calculate the transportation benefits offered by the GLSLS.

A comprehensive transportation rate and traffic analysis

was performed using a 2002 sample of 857 shipping

movements. These are origin-destination-commodity

triplets, each with an annual flow exceeding 18,000 tons.

The sample covered more than 40 different commodities

and comprised a total of 163 Mt of shipping; representing

roughly 90 percent of total tonnage through the Great

Lakes and Seaway in 2002. The study used fourth

quarter 2004 cost levels to compute economic effects on

a National Economic Development (NED) basis. The

freight rates computed for each movement are allinclusive from origin to ultimate destination, including

truck or rail legs to/from the water, loading, trans-loading

Great Lakes St. Lawrence Seaway Study 49

The Economic Importance of the GLSLS

0

5

10

15

20

25

30

35

40

45

9.0 9.0

3.5

9.6

9.8

9.3

5.9

10.1

11.8

9.5

6.1

11.1

12.0

9.6

6.7

11.6

12.1

10.4

7.0

11.8

12.2

3.0

9.0

0.7 0.4

0.5 0.7 0.7 0.7

9.5

Annual tonnage, Mt

Grain Iron Ore Coal Steel All Other

2005 2010 2020 2030 2040 2050

FIGURE 3.12

Forecast by commodity for Montreal – Lake Ontario section 

to 2050 (most likely scenario)

0

5

10

15

20

25

30

35

40

45

11.8 10.6

2.8

3.9

6.4

10.7

12.7

3.8

4.3

5.9

11.5

13.6

4.3

3.7

5.9

12.6

14.9

4.4

3.6

5.9

12.5

16.2

4.5

3.5

5.9

12.4

3.7

1.9

7.4

9.4

Annual tonnage, Mt

Grain Iron Ore Coal Steel All Other

2005 2010 2020 2030 2040 2050

FIGURE 3.13

Forecast by commodity for Welland Canal to 2050 

(most likely scenario)

0

20

40

60

80

100

120

3.6

1.2

5.5

24.2

46.1

12.5

1.3

29.7

6.5

41.7

1.3

7.6

33.5

39.1

1.4

8.6

40.7

39.1

12.5 12.5 12.5 12.5

1.4

9.6

44.7

39.1

21.7

4.1

42.7

9.6

Annual tonnage, Mt

Grain Iron Ore Coal Stone All Other

2005 2010 2020 2030 2040 2050

FIGURE 3.14

Forecast by commodity for Soo Locks to 2050 

(most likely scenario)
and unloading charges, and the main

linehaul rate (vessel, rail or truck).

The result offers a concise and reliable

estimate of the trans portation cost savings

provided to industry by the GLSLS system.

These estimates are limited, however, in

that they do not account for the

competitive effect that water way rates

have on overall rate structures in the

region, nor do they capture any benefits

associated with alleviating congestion on

highways or rail at border crossings. 

The study provides a breakdown of

shipper cost savings for 10 different

commodity groups (see Table 3.1). 

For some commodities, the savings repre -

sent the difference between breaking

even and profitability. For example, the

GLSLS offers savings of $17.37/ton for

wheat. This is 12 percent of the market

price of wheat, assuming typical wheat

prices of $150/ton. It offers savings of

$9.35/ton for iron ore. This is 23 percent

of the market price of ore, assuming

typical ore prices of $40/ton. Such

economic advantages are large enough to

be a significant factor in the economic

competitiveness of the agricultural and

steel sectors. 

Overall, the GLSLS offers shippers an

average savings of $14.80/ton in

transportation and handling charges

compared to the next-best, all-land

transportation alternative. For the period

reviewed, the GLSLS system saved

shippers a total of $2.7 billion in trans -

portation and handling charges that they

would otherwise have incurred had they

used other modes of transportation. 

The regional breakdown of shipper savings for the

system is shown in Table 3.2. This table includes the

savings for traffic that passes through each lock system

as well as for internal Great Lakes traffic that does not

pass through any navigation structures.

50 Great Lakes St. Lawrence Seaway Study

Chapter 3

TABLE 3.2

Transportation savings offered by the GLSLS by region

Commodity Sample size Savings/ Total 

Group Tons Ton savings*

Soo Locks 83,921,100 $12.98 $1,089,296,000

Welland Canal 29,746,000 $20.11 $598,277,000

Montreal-Lake Ontario 26,822,000 $22.74 $609,812,000

Internal Great Lakes Traffic not 69,832,000 $15.37 $1,073,488,000

transiting a lock

* numbers rounded to nearest 1,000

TABLE 3.1

Transportation savings offered by the GLSLS by commodity3

Commodity Sample size Savings/ Total 

Group Tons Ton savings*

Aggregates and Slag 37,813,000 $16.03 $605,988,000

Metallic Minerals and Ores 62,395,300 $9.35 $583,464,000

Coal, Coke, Pet Coke 40,783,600 $13.36 $544,961,000

Iron, Steel and Other Metals 12,872,200 $32.49 $418,219,000

Non-metallic Minerals 8,883,600 $19.50 $173,224,000

Wheat 8,046,500 $17.37 $139,776,000

Petroleum Products 3,932,500 $18.60 $73,137,000

Other Grains and Feed Ingredients 1,819,400 $28.20 $51,330,000

Soybeans 1,691,800 $22.26 $37,667,000

Corn 1,169,300 $23.61 $27,614,000

Total 179,407,200 $14.80 $2,655,360,000

* in descending order of total shipper savings, numbers rounded to nearest 1,000

3 The rate analysis did not include movements in the lower St. Lawrence River, though it did factor in movements into and out of the Seaway. 
Costs of unplanned closures

The rate analysis provided in the previous section also

points to the economic impact of unplanned short-term

closures in different parts of the system. The analysis

involved interviews with shippers in the field to determine

their likely responses to such closures. The cost to

shipping of such closures can then be determined by

comparing GLSLS costs with those of the next best

available alternative. 

For closure lasting up to 30 days, the primary impact

would likely be delays in the movement of cargoes since

shippers would be more likely at this level to wait out

the closure. Closures in excess of 90 days, however,

resulted in a modal shift to rail or truck, or both and

they could also involve shifting cargoes to different ports

on the East Coast or the Gulf of Mexico. Generally,

long-term closures would lead shippers to select an 

all-overland transportation option. 

The estimated costs incurred by shippers due to the various

unscheduled closure scenarios are presented in Figure 3.15.

A 15-day closure could reduce the cost benefit to

shippers offered by the GLSLS by $10.9 million in the

MLO section, by $12.1 million at the Welland Canal,

and by $41 million at the Soo Locks. A 180-day closure

would cost $387 million, $363 million and $661 million

respectively. 

This information provides an estimate of the benefits of

providing a reliable system. Saving money by implemen -

ting a more austere maintenance plan has to be balanced

against the frequency of unexpected closures, which result

in higher transportation costs. The trade-off between

upfront investment in infrastructure and transportation

savings is the heart of the economic analysis. 

One important finding that can be gleaned from this

closure analysis comes from analyzing the daily cost of

closure. Short closures (15 days or less) cost less than

the annual average daily benefit offered by the system

(most shippers just wait out the closure). Long closures

(90-180 days) cost the same per day as the average daily

benefit (as would be expected). The response to a 

30-day closure is somewhat different, because of the cost

implications of a short-term re-routing. The Soo Locks,

in particular, see a significant cost impact for a 30-day

unscheduled closure. This is associated with the captive

nature of the coal and ore trades in these locks and the

difficulties involved in re-directing such massive

volumes through alternative routes. The other locks in

the system are not nearly as sensitive to closures, as the

daily costs of closure are essentially equal to the daily

net benefits offered by the system. This reduced

sensitivity to closures in the lower Great Lakes reflects

the relative availability of alternative transportation in

the region, making shifts in modality relatively

inexpensive. An important exception to this, however,

is the steel industry in Canada. System closures 

would close the steel mills as there is no other supply

option available.

The Economic Importance of the GLSLS

0 100 200 300 400 500 600 700

15 

30 

90 

180 

$ Millions

Length of unscheduled closure (days) 

Soo Locks 

Welland Canal 

Montreal-Lake Ontario 

FIGURE 3.15

Estimated costs of unscheduled lock closure

Great Lakes St. Lawrence Seaway Study 51
CONCLUSIONS

For half a century, the GLSLS system has played a vital

role as a major transportation corridor serving the

commerce of the Great Lakes and St. Lawrence River

basins. During that time, its role has evolved to accommodate changing economic circumstances and its economic

contribution remains significant on a regional and

national level. Even so, the GLSLS remains focused on

the delivery of bulk goods, such as iron ore and coal to

domestic markets, while also participating in the

downbound flow of grain for trans-Atlantic export. 

The GLSLS continues to make a significant contribution

to the regional economy of the Great Lakes and through

it, to the economy of North America as a whole.

Admittedly, there have been fluctuations in total

tonnages carried through the system over the past fifty

years, reflecting changes in the supply of and demand for

different commodities. The past few years, however,

have seen these traffic levels stabilize to about 260 Mt

annually. This volume of traffic simply could not be

transferred to an already overloaded land-based transpor -

tation network without severe economic impacts on the

industries served. Marine transportation continues to be

a viable and essential complement to the existing road

and rail transportation networks in the region. Since

trade volumes are expected to increase in coming years,

marine transportation is likely to grow in importance.

At current traffic levels, the GLSLS system has an

enormous potential asset in terms of unused capacity.

With growing pressure on land-based transportation

networks in the region, there is a possibility of using 

the GLSLS to relieve some of that pressure.

52 Great Lakes St. Lawrence Seaway Study

Chapter 3
CHAPTER 4

Environmental Considerations

The Great Lakes basin and St. Lawrence River is a unique 

water resource of major significance to the environment. 

As the world’s largest fresh water system, it supports the 

livelihood and activities of 10 percent of the U.S. and 25 percent of 

the Canadian population. This ecosystem has been degraded by many

different human activities, one of which is commercial navigation. 

The ecological state of the region’s associated lakes and rivers 

as well as the fish and wildlife that rely on them has a direct impact 

on the future vitality of the Great Lakes St. Lawrence Seaway system.

The size of the system and the volume of traffic passing 

through it inevitably affects the surrounding environment. 

Yet commercial navigation is only one of the many factors 

influencing the environment. To preserve and maintain the region’s

vitality, it is critical to identify and control the most significant

navigational and non-navigational environmental stressors. 
An important component of the GLSLS Study is consideration of the impact of the GLSLS system on the regional

environment. The Environmental Working Group was

mandated to address this issue. Its primary goal was to

review the current environmental conditions present in

the Great Lakes basin and St. Lawrence River, high -

lighting in particular the impacts on the environment

arising from commercial navigation. In addition, the

Working Group looked at anticipated future trends that

may affect key ecosystem components. Finally, it

considered ways of mitigating any future negative

environmental impacts associated with commercial

navigation through the GLSLS system. 

Within this context, the Environmental Working Group

considered the environmental implications of potential

changes to the volume or type of traffic passing through

the system as well as any effects associated with operating

or maintaining the infrastructure of the GLSLS. 

OVERVIEW

The Great Lakes basin and St. Lawrence River together

encompass the world’s largest fresh water system,

supporting the livelihood and activities of approximately

33 million people living within its catchment area. 

This vast watershed provides drinking water, and supports

domestic, municipal, industrial, recreational and trans -

portation needs throughout the region. Its waters are used

for hydroelectric power generation, waste water disposal,

recreational boating, tourism, natural wetlands and a

range of interdependent and unique habitats and species,

as well as the commercial navigation of the GLSLS

system itself. The GLSLS system, therefore, exists within

this complex network of human activities and environ -

mental relationships, all of which originate with and

depend on the waters of this immense region. 

Development in the region dates back several centuries

since the St. Lawrence River was the first gateway into

the continent for European settlers. Early economic

activities included the fur trade and commercial logging.

The Great Lakes and St. Lawrence River were also used

for subsistence fishing which eventually evolved into an

important commercial fishery. Without governmentimposed catch limits, however, overfishing depleted fish

stocks. Agriculture grew steadily to the point where it

currently accounts for approximately 33 percent of land

use in the Great Lakes basin, dominating the riparian

area of the St. Lawrence River, and contributing

fertilizers and herbicides into the ecosystem. The growth

of cities in the region brought discharges of sewage and

polluted air. About 26 million of the basin’s inhabitants

54 Great Lakes St. Lawrence Seaway Study

are now concentrated in five major metropolitan areas

(Chicago, Toronto, Detroit, Montreal and Cleveland).

All of these major centers and several smaller ones have

well-developed industrial bases which are associated

with the discharge of heavy metals, organic compounds

and a variety of other pollutants. In other words, forestry,

fishing, agriculture, urbanization and industrialization

have each brought permanent environmental changes to

the basin. 

Within this broader context, there is a separate though

cumulative set of environmental effects associated with

commercial navigation through the GLSLS system.

Some of these derived from construction activities,

dredging, or the effect of ship wakes. As infrastructure

and additional connecting bodies of water were created

to support shipping traffic and commerce, aquatic nonindigenous invasive species (NIS) were introduced.

Chapter 4

Canada Goose, Kent Lake Kensington Metro Park, Michigan

Source: U.S. Environmental Protection Agency, Great Lakes

National Program Office, www.epa.gov
Many of these established themselves permanently,

affecting both human activities and the basin’s flora and

fauna. The completion of the GLSLS system in 1959 was

also accompanied by a management regime for water

levels that brought additional environmental impacts. 

To evaluate the environmental context within which the

GLSLS waterway operates, the Environmental Working

Group examined the environmental stresses affecting 

the key ecosystems of the region. It considered both the

stresses due directly to navigation and stresses that were

not related to navigation and that did not involve major

socio-economic structural changes or catastrophic

environmental events. It also evaluated the potential

cumulative effects of all environmental stresses acting

together. While navigational factors can operate

separately and independently of other stressors, there are

cases in which navigational and non-navigational stressors

can have a synergistic or cumulative impact on the

environment.

VALUED ECOSYSTEM

COMPONENTS (VECS)

To make analysis manageable given the diversity of the

region’s ecosystems, the Environment Working Group

focused on its most important valued ecosystem compo -

nents (VECs). The VEC approach is a widely used tech -

nique for focusing environmental assessments on those

components that have the greatest relevance in terms of

value and sensitivity to specific issues. The Canadian

Environmental Assessment Agency defines a VEC as:

Any part of the environment that is considered

important by the proponent, public, scientists and

government involved in the assessment process.

Importance may be determined on the basis of cultural

values or scientific concern (CEAA, 1999)1

Because this type of environmental assessment is driven

by relevance to particular concerns, in the GLSLS Study

it was used to examine the impact of commercial

navigation. The Environmental Working Group organized

its analysis under three categories of VECs – Air, Terrestrial

Ecosystems, and Aquatic Ecosystems (see Table 4.1). 

It then focused specifically on the impacts on these

VECs that were related to navigation.

Air quality

Air quality is significantly affected by population density,

the nature of the industrial base and geographical

location. For example, levels of air pollution initially

were low in the upper basin, but increased in the years

just before and just after 2000. In contrast, levels of air

pollution have declined in airsheds around the lower

basin lakes. Air quality is largely affected by urban and

industrial emissions as well as long-range transportation

and it varies according to weather. Studies conducted by

Environment Canada have shown gradual improvement

in air quality in major urban centres between 1974 and

1992. Overall emissions of greenhouse gases (GHG)

increased by 24 percent during the period between 

1990 and 2003. Over the same period, Gross Domestic

Product (GDP) grew by 43 percent, which means that

there was a reduction in the amount of GHG emitted

per unit of GDP.

Environmental Considerations

1 CEAA (1999) Cumulative Effects Assessment Practitioners Guide http://www.ceaa.gc.ca/013/0001/0004/index_e.htm

TABLE 4.1

Valued Ecosystem Components

VEC Groups VECs VEC Descriptions

Air Air quality Nitrogen oxides (NOx), sulphur oxides (SOx), carbon dioxide (CO2), 

carbon monoxide (CO), dust and other particulate matter (PM)

Soil and Ground Water Contamination

Vegetation Limited to nearshore upland vegetation

Fauna Terrestrial fauna excluding aquatic birds and shorebirds

Special features Islands

Water and Substrate Water quality, water quantity and substrate

Flora and Wetlands Wetlands and phytoplankton

Aquatic fauna Fish, benthic invertebrates, zooplankton, semi-aquatic species (e.g., amphibians,

reptiles, waterfowl, shorebirds, etc.)

Terrestrial Ecosystems

Aquatic Ecosystems

Great Lakes St. Lawrence Seaway Study 55
The transportation sector as a whole contributes 27 percent

of total GHG emissions. But less than three percent of

all GHG emissions come from shipping. Because each

vessel can carry a very large amount of cargo, shipping

remains more fuel efficient overall than rail or truck; it

consumes less energy and creates fewer emissions. Even

so, ships in port have a negative impact on air quality by

releasing high concentrations of SOx, NOx, and PM

Some of this is attributable to “hotelling” practices in

which ships at port continue to run their engines to

generate electrical power. Some is attributable to the

burning of poor quality fuel. While the global effect of

these factors is small, local impacts can be more intense.

However, emissions from ships are increasingly regulated,

and some progress has been made in switching ships to

cleaner-burning fuel.

Terrestrial ecosystems

Soil and Ground Water: Though impacts vary through -

out the basin, the quality of soil and ground water has

generally fallen in response to development and indus -

trialization. Navigation-related activities can degrade soil

and ground water in two ways. First, the development

and use of port infrastructure and related industrial

development can contaminate soil while industrial and

toxic materials can similarly affect water. Second, the

terrestrial placement of dredged material can affect both

soil and ground water quality, depending on the character

of the material deposited and the condition of the site

prior to disposal. For example, if sediments are highly

polluted, toxic materials can find their way through the

soil and ground water into the food web.

Vegetation: Agriculture is often practiced close to the

water’s edge, thus altering natural vegetative cover.

Urban and industrial development inevitably affects

nearshore upland vegetation. In addition, both native

and non-indigenous invasive species have colonized

disturbed areas and now dominate the landscape. In

terms of navigation, nearshore vegetation and habitats

have been changed and even eliminated as a result of

efforts to alter shorelines or harden them as part of port

development or erosion control. The placement of

dredged material has also modified natural areas. Finally,

air emissions including contributions from ships have

had some localized impacts. 

56 Great Lakes St. Lawrence Seaway Study

Fauna: Habitat destruction and fragmentation caused by

both urban and industrial development have reduced

breeding areas, viable wildlife populations, and species

numbers. Noise and other disturbances have resulted in

displacement or elimination of many native wildlife

species. In places, port development and maintenance

have eliminated viable mammal, reptile and bird

populations. In areas of dredge disposal, different

habitats have been created that, in some areas, helped

the recovery of bird populations, and in others, attracted

birds into contaminated areas. Ice breaking, to keep

channels open, has disrupted animal movements across

ice and affected predator-prey relationships.

Islands: Because of their unique habitats and intact

ecosystems, islands are considered special features of the

Great Lakes and St. Lawrence River and deserve special

attention. Islands provide unique wildlife and fish habitat,

recreational opportunities, and locations for navigational

aids. There is a tendency toward endemic species and 

a frequent lack of mammalian predators on islands.

Biodiversity is relatively high due to edge-effect; the

presence of shoals supporting fish nurseries; and important

avian nesting and stopover habitats. There are thousands

of islands that range in size from the very large, such as

Isle Royale in Lake Superior and Manitoulin Island in

Lake Huron, to the extensive archipelagos of smaller

islands, such as the 30,000 Islands of Georgian Bay and

the Thousand Islands and the Sorel Archipelago in the

St. Lawrence River. Most of these islands are naturally

formed, but some may be anthropogenic, usually a result

Chapter 4

Sorel Inlands, Quebec

Source: Environment Canada
of the deposition of dredge material. The environmental

condition of these islands also varies from pristine

habitats in Lake Superior to the highly degraded islands

of the Detroit and St. Lawrence rivers. 

One of the most serious threats to islands is the loss of

biodiversity, caused by increased development and

recreation, unsustainable forestry and agricultural practices,

introduction of non-indigenous species, contaminants,

water level change, habitat fragmentation, and deposition

of dredge material. Reduced biodiversity on islands may

be more ecologically significant than in non-island

habitats because of the limited connection islands have

with adjacent mainland habitats, making them less

resilient to perturbations. The introduction of nonindigenous species may present a greater threat to diversity

on islands than in mainland habitats because of the

lower level of ecological resilience that islands inherently

support. Increased human development, including home

building and recreation, may serve to jeopardize the eco -

logical isolation that also makes island ecosystems unique.

Erosion is a common phenomenon on islands, and may

be more significant on islands made of unconsolidated

sediment (e.g., sand, silt) or sedimentary rock. Water,

waves, and wind-related erosion may be exacerbated by

human activities, such as the removal or modification 

of shoreline vegetation or placement of armouring or

jetties that interfere with normal littoral drift processes. 

Development and operation of the commercial naviga -

tion channels have removed islands or affected islands

through direct operational practices, such as dredging

and dredge material disposal, and through water level

regulation. Commercial navigation has involved 

vessel-induced wakes, ice scour, and pressure waves

under the ice, all of which contribute to shoreline

alteration and erosion. 

Aquatic ecosystems 

Water Quality: Bodies of water are categorized by their

biological productivity and nutrient levels. Within the

Great Lakes, at one end of the spectrum is Lake Superior,

which has been least affected by agriculture, urbanization

and industrial development: it is characterized as oligo -

trophic, which means it contains low levels of nutrients.

Such lakes are typically very clear and rich in oxygen

with low levels of algal growth and biological activity.

At the other end of the spectrum are the eutrophic lakes,

such as Lake Erie. In these lakes the accumulation of

nutrients accelerates algal growth and, as biomass

decays, oxygen may decrease to levels that affect species

in the lake. 

Great Lakes St. Lawrence Seaway Study 57

While open water phosphorus concentrations have

decreased in lakes Michigan, Erie and Ontario, every lake

still features high local concentrations in some areas.

The nutrient load, both phosphorus and nitrogen, of the

St. Lawrence River impairs the St. Lawrence maritime

estuary and the Gulf of St. Lawrence. Oxygen concentrations decrease in the deep Laurentian Channel, partly 

as a result of the increased oxygen demand due to

remineralization of augmented amounts of organic

matter in the sediment. A decrease in nutrient loads of

both nitrogen and phosphorus in the river could

improve the situation. 

While efforts to reduce nutrients were successful during

the 1980s and early 1990s, Lake Erie continues to show

signs of eutrophication, as is the case in Lake Ontario

and Lake St. Pierre in the St. Lawrence River, although

the situation is probably less severe in these two lakes.

From 1995 through 2003, the winter and early spring

concentrations of phosphorus increased continuously.

Recently, scientists have observed anoxic events and

dense blooms of cyanobacteria, regularly noted in the

1950-1970s. The major difference, however, is that toxic

cyanobacteria species are now common. 

The Great Lakes basin and St. Lawrence River contain 

a legacy of chemical contamination. Throughout the

basin, trends in contaminant levels show that polycyclic

aromatic hydrocarbons, polychlorinated biphenyl

(PCBs), pesticides, heavy metals and other toxins have

generally decreased. Even so, there are still localized

high concentrations that remain a concern. In addition

to traditional or legacy contaminants, concerns are

being raised about the levels of pharmaceutical, personal

care products and chemicals such as polybrominated

diphenyl ether (PBDEs) that are now found in the lakes

and the St. Lawrence River. 

Municipal infrastructure improvements throughout the

basin have significantly improved the effectiveness of

municipal sewage treatment. However, continuing

problems and challenges remain for many cities due to

aging infrastructure and the limited capacity to treat

water during storm events. 

To address these water quality concerns, the governments

of Canada and the U.S., in cooperation with the

provincial and state governments, have designated the

most polluted areas of the Great Lakes as Areas of

Concern (AOCs) and are developing and implementing

Remedial Action Plans (RAPs) to address each area’s

specific water quality problems and sources. In total, 

43 AOCs were designated, of which 3 have been

remediated and taken off the list. Currently there are 

25 areas in the U.S., 10 in Canada, and 5 that are

shared by the two countries. Some of these AOCs are

located in or close to port areas. A companion program

Environmental Considerations
of Priority Intervention Zones (ZIPs) was initiated by 

St. Lawrence River communities in Quebec to develop

local and regional action plans for addressing chemical

contamination, physical and biological degradation, and

socio-economic opportunities for development. 

Contaminants may also affect lake and river sediments,

which in turn, can affect overall water quality. The

decreasing concentrations of PCBs and heavy metals in

the water column, for example, have led to a decrease in

concentrations of these contaminants in surface sediments.

However, deeper sediment still maintains high levels of

legacy pollutants that may become exposed during

dredging operations. Erosion and deposition, brought

about by changes to flow patterns associated with river

channelling and flow controls and in some circumstances

by ship wakes, has also affected sediments.

There are both direct and indirect effects on water

quality attributable to navigation. Indirect contributions

include the development of port facilities, the resulting

discharge of contaminants from construction and

maintenance activities, and industrial and population

growth resulting from port availability. Direct contributions

occur with dredging and channel maintenance activities,

ship passage impacts, waste disposal, accidental or

incidental discharges of contaminants, and cargo sweeping

activities. Ship passage impacts include bottom scouring

and prop wash, both of which contribute to increased

turbidity and a re-suspension of sediments and trapped

contaminants in the water column. Dredging and

channel maintenance activities can also release conta -

minants into the water column. Inappropriate waste

disposal and the incidental release of petroleum products

or bilge water also contribute to degraded water quality.

The activity of cargo sweeping in ports may lead to

elevated nutrient levels resulting from incidental

discharge of dry cargo residue, such as wood chips, coke,

potash, limestone, iron ore, foundry sand, salt, fertilizer,

and grain. Generally, the impacts of this practice are

poorly understood.

Water Quantity: The ecology of the Great Lakes basin

and St. Lawrence River is highly dependent on water

levels and circulation patterns in the system. Water

levels and flows are affected by both natural features 

and human activity.

The Great Lakes were formed during the retreat of the

Wisconsin glacier some 10,000 years ago. The retreating

glaciers formed ridges of land, between which melting

waters formed immense lakes. The shape of the lakes

changed over time as the glaciers retreated northward.

The immense size and weight of the glaciers, thousands

of metres thick in places, depressed the Earth’s crust,

which began to rebound as the glaciers retreated. This

glacial rebound continues today at varying rates, with

58 Great Lakes St. Lawrence Seaway Study

areas north of Lake Superior rebounding at rates of up to

60 cm (20 in) per century while the southern reaches of

the basin are rebounding at only 10 cm (4 in) or less 

per century causing a shift in elevation around the lakes

and thus affecting the shoreline. Since the retreat of 

the glaciers, lake levels have fluctuated enormously in

response to climate variations and the ongoing evolution

of the drainage basin. Levels have varied by more than

100 metres (300 ft), leaving the marks of ancient

shorelines high up on the hillsides of the lakeshores and

the remains of an ancient forest on the floor of southern

Lake Huron. Even today, crustal rebound, climate

variations, and erosion and deposition processes continue

to alter the size and shape of the lakes.

Natural variations in precipitation and evaporation

cause fluctuations in lake levels on both a seasonal and 

a decadal scale. The annual cycle of precipitation and

runoff results in the lowest lake levels occurring at the

end of winter after which water levels rise in response to

snowmelt, runoff and precipitation. Winds, barometric

pressure fluctuations and ice jams also contribute to

short-term variations in lake and river levels throughout

the system. Ice cover has a considerable influence on

water levels by influencing the amount of evaporation. 

Humans affect water levels through the manipulation of

locks, dams and control gates constructed as part of the

Seaway and hydroelectric system. In fact, a major effect

of GLSLS infrastructure was to reduce natural fluctu a -

tions of the water levels in the St. Lawrence River and

on lakes Ontario and Superior. 

Diversion of water out of the Great Lakes system has

faced public and government scrutiny. There are three

primary water diversion locations, but none are part 

of the Seaway system. There are two diversions into

Lake Superior from Long Lac and Ogoki, both in

Canada. The Chicago diversion directs water out of

Lake Michigan and eventually into the Mississippi River

for purposes of sanitation, navigation and hydroelectric

production. Taken together, these three diversions result

in a net inflow of water of 67 cubic metres per second

(m3/sec) and represent one percent of the average

annual inflow into the Great Lakes.

The ongoing operation of the navigation system relies, in

part, on the regulation of water levels and flows within

the Great Lakes and the St. Lawrence River region. 

The International Joint Commission (IJC) was established

by the Canadian and U.S. governments to address

boundary water issues. It has the authority to permit

construction and oversee the operation of structures to

regulate water levels on the Great Lakes. Water levels

on Lake Superior are regulated by compensating gates

located on the St. Marys River and water levels on the

St. Lawrence River are regulated by controlled releases

Chapter 4
of water from the Moses-Saunders power generating

station, which also directly affects levels in Lake

Ontario. These control measures take into account

anticipated natural rates of precipitation, runoff 

and evaporation.

The construction of navigation-related infrastructure 

has resulted in a significantly altered flow regime. The

dredging of the upper St. Clair River has permanently

lowered the water levels of lakes Huron and Michigan

by 38 cm (15 in). Prior to regulation of its outflow in

1959, water levels in Lake Ontario fluctuated by as

much as 2 m (6.6 ft). The existing regulation plan has a

narrower target range of 1.2 m (4 ft). The reduction in

water level fluctuations has also led to a greater range of

flows in the St. Lawrence River. What is more, with the

influence of climate change, predictive models suggest

that the flow of water to the St. Lawrence River will

likely decrease by 4 to 24 percent by 2050. Depending

on the scenario used, significant water level declines

may be experienced in all of the Great Lakes. 

Substrates: The term substrate refers to the soil,

sediment and other material found at the bottom of a

waterway that provide the medium for aquatic plants,

bottom-dwelling (benthic) organisms and bacteria.

These substrates often contain contaminants that enter

the water and then settle to the bottom. Chemical

contaminants often remain in the substrates until they

are disturbed. Near shores, substrate material is generally

sandy but away from the shore, the sand is mixed with

silt and/or clay. At greater depths, the sediments are a

mixture of clay and fine-grained sediment.

Infrastructure construction, maintenance and ship oper -

ations can affect substrates. The construction of channels

and ports was associated with significant dredging and

deposition of dredge material. This substrate disturbance

often releases toxic contamination and alters habitats.

Ship operations can result in scouring of substrate materials,

re-suspension of materials, and erosion of shallow water

areas. Ice breaking operations can result in bottom

scouring. All of these effects can be exacerbated by

reduced water levels.

Wetlands: Wetlands are generally saturated with water

long enough to promote wetland or aquatic processes 

as indicated by poorly drained soils, hydrophytic vege -

tation, and various kinds of biological activity that are

adapted to a wet environment. The extensive coastal

wetlands of the Great Lakes basin and St. Lawrence

River are vital ecosystems that contain a diversity of

plants, including many significant and rare species; and

provide important breeding and migratory habitat for

waterfowl, as well as feeding, shelter and spawning areas

for many species of fish. Wetlands also provide natural

water storage and a cleansing function contributing to

Great Lakes St. Lawrence Seaway Study 59

the natural hydrologic processes. The loss of wetlands

reduces both the quantity and the quality of suitable

habitat for hundreds of species of flora and fauna, and

thus diminishes biodiversity.

In the past, wetlands were often viewed as wastelands

and subjected to development, shoreline hardening and

land-filling, creating widespread habitat loss, degradation

and reduced diversity. More than two-thirds of the

region’s natural wetlands have been filled or drained

over the past century. The losses are most pronounced in

the lower lakes, most notably in the St. Clair – Detroit

River region, Lake Erie and Lake Ontario, and in the

Montreal area along the St. Lawrence River where

wetlands were either lost or changed character as a

result of the permanent flooding caused by creation of

the Seaway.

Environmental Considerations

Little Canal, Lake Superior, Wisconsin

Source: U.S. Environmental Protection Agency, Great Lakes

National Program Office, www.epa.gov
The rate of wetland habitat loss and degradation has

slowed considerably during the past decade with the

implementation of more comprehensive habitat protection

programs and policies, and because there are so few

wetlands left. Incremental losses still occur, however, in

locations experiencing increased development pressure

and water level regulation.

Climate change and its potential to permanently lower

water levels may reduce the size, complexity, and acces -

sibility of some wetlands. In other places, it may result in

the opposite: deeper areas may become shallow enough

to support the development of wetlands. A change in

geographic range inhabited by some species will affect

overall species composition in the region. 

Most wetland depletion has occurred as a result of 

non-navigation-related activities. However, future landbased development in support of commercial navigation

could eliminate or alter wetlands if it is not properly

located, designed and operated. In narrow channels,

wetlands are adversely affected by prop wash and surge.

The impacts include erosion of the shoreline and littoral

zone and the dislodging of submerged vegetation. Water

level changes can adversely affect wetlands either

through flooding or drying. The introduction of NIS by

shipping activities can affect the diversity of species 

in wetlands. 

Plankton: The bacteria and plankton that support the

food chain in the Great Lakes have been affected by

nutrient concentrations associated with various types of

pollution. As regards navigational impacts, the most

significant has arisen from the introduction of NIS. 

For example, the larval stage of the zebra mussel has

become prevalent within zooplankton communities in

parts of the Great Lakes basin and St. Lawrence River

and adults of this species reduce their phytoplankton

density by their filtering activities. This seems to be

exerting pressure on other species that are key components

of the food web. In general, the functioning of the tradi -

tional zooplankton community throughout the region

has been significantly altered as a result of NIS. This is

an impact that is directly attributable to navigation

inasmuch as the new species seem to have entered 

the region in the ballast water of vessels using the

GLSLS system. 

Lakebed organisms: Bottom dwelling organisms have

experienced major changes over the past two decades.

Non-indigenous zebra mussels and quagga mussels have

severely decreased native mussel populations. They have

also taken over or modified part of the habitat, with a

corresponding impact on other species and changes to

60 Great Lakes St. Lawrence Seaway Study

the native food web. The deposition of faeces and

pseudofaeces has locally increased the organic matter

content in sediment. This, in turn, has increased

microbial activity and stimulated activity of other

benthic organisms as well as their diversity and density.

Increased biogenic carbon content in sediment increases

the consumption of oxygen by lakebed organisms and

can result in oxygen depletion in the deeper layers of

the lakes. This, in turn, may kill a large portion of the

lakebed community. This phenomenon is important

especially in Lake Erie and in the deep Laurentian

Channel in the Gulf of St. Lawrence.

In addition, there are direct vessel-induced impacts

resulting from grounding and anchoring. Effects include

crushing, scraping and displacement of lakebed organisms

and the altering of their habitat. Scouring from prop

wash or drawdown and surge waves in shallow areas can

have similar impacts on lakebed organisms. Development

of the navigation system altered the habitat in the

connecting channels and dredging or new construction

can cause the displacement or burying of organisms as

well as the permanent alteration of habitat.

Fish: Fish communities in the Great Lakes basin and 

St. Lawrence River have been negatively affected by

habitat loss, over-fishing, chemical contamination, and

other disruptions to the ecosystem, and especially the

introduction of NIS. Prior to the invasion of the sea

lamprey above Niagara Falls, Great Lakes fish commu -

nities were stressed by high fishing pressure and habitat

loss. Once sea lamprey populations were established

above Lake Ontario in the 1930s, the increased stress

from sea lamprey predation was the straw that broke the

back of the native lake trout in all lakes except Lake

Superior where remnant lake trout stocks persisted until

efforts to control lamprey numbers took hold. With top

predator numbers reduced to near zero, populations of

invading prey fish such as alewife, rainbow smelt and

gizzard shad exploded: in Lake Michigan massive die-offs

of alewife created a public nuisance by the 1960s.

Effective measures to control sea lamprey numbers and

the mortality they inflicted on Great Lakes fish began in

the 1960s. Shortly after lamprey control efforts were

initiated, federal hatcheries increased the number of

lake trout stocked for rehabilitation and state fishery

agencies introduced pacific salmon to control the over

abundance of alewife. The increase in trout and salmon

predators led to the stabilization of fish communities.

With the rehabilitation of self-sustaining lake trout

populations in Lake Superior, the fish community is

generally considered to be restored and re-stocking

efforts have therefore been somewhat reduced. Walleye

Chapter 4
populations have also recovered in Lake Erie. The

stocking of trout and Pacific salmon continues in the

other Great Lakes, though there are self-sustaining

populations of Pacific salmon in Lake Huron. Other

native species such as lake herring deepwater ciscoes,

lake whitefish, and yellow perch, were once extremely

reduced after the invasion of sea lamprey and alewife,

but they also have generally rebounded. Fish communities

have also changed over the last decades in the St. Lawrence

River because of many dynamic factors, some of which

are related to the modification of the hydrology and the

use of shorelines.

Even so, persistent and continued invasions by species

such as zebra and quagga mussels, round and tubenose

gobies, ruffe and other zooplankton remain a serious

threat to the stability of the food webs and fish

communities of the Great Lakes. 

The passage of vessels may affect fish populations

directly through the entrainment of fish in propellers; 

by disturbing resting fish, and by inducing abnormal

activity and stress during winter months as a result of 

ice breaking; by displacing egg and larval stages from

spawning and nursery areas; and by causing siltation in

spawning areas. Other significant impacts have been

connected to the alteration of habitats during the

development of the navigation system. 

EVALUATION OF

STRESSORS

In evaluating the stressors affecting VECs, the study

differentiated between those associated with navigation

and those associated with other factors, such as

population pressure, economic development, or tourism

and recreation (see Table 4.2). Climate change was

considered separately because of its far-reaching effects

and because it can influence both navigational and nonnavigational stressors. Non-navigational stressors are

those related to development and land use and those

related to water-based recreation and tourism.

Navigation-related stressors include: 

• stresses to shorelines and channels as a result of

dredging operations and port maintenance;

• stresses related to the management of water levels for

navigational requirements;

• stresses caused by land based activities in support of

navigation such as facility construction or

maintenance; and

• numerous stresses arising from ship operations,

including pollution and spills, turbulence associated

with ships’ wakes, and the introduction of aquatic

non-indigenous invasive species (NIS).

Issues related to channel and port

maintenance

Parts of the GLSLS system require ongoing dredging 

to maintain the navigability of ports and channels.

Environmental impacts related to dredging activities

may include:

• turbidity, reduced light penetration and increased

suspended particles, during both dredging and

disposal of the dredged materials; 

• re-suspension of materials from waterway bottoms 

and possible release of contaminants, nutrients, gasses

and oxygen-consuming substances trapped in bottom

sediments;

• impacts on fish and fish spawning habitat;

• removal of important organisms living in or on the

bottom substrate;

• altered water flows in wetlands and the loss of

wetland habitat; and

• decreased water flow velocities in areas outside of the

navigation channel with associated sedimentation. 

Environmental Considerations

Lake St-Pierre, Quebec

Source: Environment Canada

Great Lakes St. Lawrence Seaway Study 61
For example: 

• the dredging of shipping channels in near-shore

waters, harbour construction and shipping at river

mouths contributed to a decline in the organisms

living in areas of Lake Superior and changed the

wetland regime in parts of the St. Lawrence River

such as Lake St. Pierre;

• channelling in the St. Marys River may have

eliminated many of the spawning sites used by lake

herring; and

• the dredging of the St. Clair and Detroit rivers have

cumulatively lowered the levels of Lake Huron and

Lake Michigan by some 38 cm (15 in). This dredging

included commercial gravel mining (in the 1920s) and

navigational improvements (from the 1800s to 1962). 

The disposal of dredged material causes additional

impacts. Terrestrial placement can result in odour, dust

and reduced air quality. Ground and surface water

quality may also be affected by turbidity and/or chemical

contamination. Disposal in wetlands is of particular

concern inasmuch as dredged materials can alter or

disrupt a wetland ecosystem. Effects can include animal

disturbance or displacement, changes to surface water

quality, discharge of fine particulate matter, sedimen -

tation and burial of organisms, release of toxic substances,

loss of productive habitat, and introduction of invasive

species. Dredged material deposited in open water or 

in confined waters may alter currents or water flows,

promote siltation, increase turbidity, release toxic

materials, bury or displace organisms, or deprive species

of spawning or rearing habitats. 

There are cases, however, where the placement of

dredged material can actually benefit the environment

by creating new habitats in highly altered sites such as

old quarries. Careful placement of dredged materials can

also offset the erosion of natural shorelines or build

artificial wetlands. Over the past 20 years, regulations

regarding the potential environmental impact of dredging

activities have been strengthened. Ports and federal

government agencies throughout the basin follow these

new more stringent regulations and apply “best manage -

ment practices” to dredging and dredged material

placement programs under the guidance of projectspecific environmental impact assessments. In some

instances, significant efforts go into ensuring that

dredged materials are used beneficially in creating or

restoring wetland habitats, although such activities are

limited to the scale of the system .

62 Great Lakes St. Lawrence Seaway Study

Chapter 4

TABLE 4.2

Environmental stressors 

Class of stressor Stressor 

Global Climate change

Water withdrawal & diversions

Introduction & transfer of aquatic NIS

Air emissions

Industrial/municipal effluent

Solid waste disposal

Landscape fragmentation

Runoff

Shoreline alteration/hardening

Noise & vibration

Erosion and sedimentation

Introduction & transfer of aquatic NIS

Shoreline alteration/hardening

Waste disposal/pollution

Erosion and sediment re-suspension

Wildlife conflicts

Channel modification

Dredge material placement

Shoreline alteration/hardening

Maintenance dredging

Water management for all purposes

Infrastructure development

Facility maintenance

Uncontrolled releases

Introduction & transfer of aquatic NIS

Ship’s air emissions

Biocides (antifouling)

Accidents/spills

Noise & vibration

Waste disposal

Prop wash, surge and wake

Cargo sweeping

Groundings/anchoring

Wildlife encounters

Ice breaking

Non-navigational related Navigational related 

Development 

and land use 

Water-based 

recreation and 

tourism 

Channel & port

maintenance 

Water management

Land-based support

activities 

Ship operations 
Water management

Human regulation of water levels is undertaken throughout the region for a number of reasons including power

generation and shoreline protection, and to a lesser

extent for recreation and navigation. Water management

can interfere with the natural cycles prevalent in certain

ecosystems. Flora and fauna in the region have adapted

to seasonal fluctuations in water levels but, when these

are reduced or disrupted by water level regulation, there

can be significant impacts on factors such as breeding

cycles. Regulation of water levels can transform entire

ecosystems, as in the case of Lake St. Francis and 

Lake St. Lawrence, which were river environments until

the advent of water regulation. 

Land-based support activities

The GLSLS system is associated with a variety of

environmental impacts that are related to infrastructure

development, facility maintenance and uncontrolled

releases of various materials. The construction of its

ports, harbours and marinas has had major individual

and cumulative environmental impacts. These include:

• loss of, or serious modifications to, terrestrial and

aquatic habitats important to breeding, spawning 

and rearing;

• loss of staging areas for migratory species;

• hardening and other alterations to shorelines that

affect coastal processes;

• release of nutrient, toxic and noxious substances into

local air and watersheds as a result of construction

and operations; and

• noise, traffic, and other social impacts to local

communities.

Water flow patterns that have been permanently altered

because of land development can drastically affect the

local aquatic environment through changes in water

quantity and quality. Routine repair and maintenance of

facilities perpetuate many of these impacts since infra -

structure is aging and requires more major maintenance

work or even replacement. Expansion or replacement of

multimodal connections has generated constructionrelated effects and long-term impacts such as habitat

fragmentation or removal. Shoreline hardening and

modifications can destroy riparian communities and

alter near-shore aquatic habitats. Air quality suffers from

industrial and transportation-related emissions, dust and

other particulate matter. Soil and ground water contami -

nation can result from uncontrolled releases such as bulk

storage facilities. Both terrestrial and aquatic fauna can

be displaced or disturbed and habitat destroyed. 

Great Lakes St. Lawrence Seaway Study 63

Ship operations

Ship operations can have direct and indirect impacts.

Direct impacts are those that cause damage or mortality

to a resource. Examples of these direct impacts include:

• shoreline erosion;

• risks associated with accidental groundings, including

spills;

• waste discharges;

• disturbance of the benthic layer;

• habitat disturbance and wildlife encounters;

• larval or adult fish entrainment by ship propellers;

• physical impacts to plants or shorelines due to passing

vessels (wake and propeller wash);

• crushing/scraping of bottom-dwelling aquatic

organisms; and

• impacts of vessels in turning basins or fleeting areas

where, for example, turning propellers or dragging

anchors might mechanically disrupt sediments.

Indirect or secondary impacts from ship operations are

those that decrease the survival rates of a resource over

time or that have a negative impact on the requisites for

life. Examples of indirect impacts include:

• the effects of suspended sediment on plant growth

and mussel physiology;

• sediment deposition into backwaters and secondary

channels; and

• reduction or loss of spawning or over-wintering

habitat through sedimentation.

In the St. Marys River, for example, wetland and spawning

habitat loss, shoreline erosion and habitat degradation

have resulted from wave action and turbidity. Traffic by

large vessels has affected the survival of lake herring eggs

due to excessive wakes and turbulence. Wake and

drawdown flows from passing ships disturb bed sediments,

resulting in a loss of lake-dwelling organisms and may

result in the re-suspension of contaminants. Some areas

of the St. Lawrence River have been subject to intensive

shoreline erosion and the biological impacts of this have

not yet been thoroughly assessed. 

The following are the most significant environmental

influences observed within the Great Lakes basin and

St. Lawrence River as a result of the normal operation 

of ships navigating through the GLSLS.

Environmental Considerations
Air emissions: Ship engines do cause some air pollution.

It can be argued, however, that a much larger amount of

potential pollution is eliminated because of the transfer

of traffic away from road and rail. Shipping is more fuel

efficient than rail or truck which means that relatively

less energy is consumed and there are lower emissions.

On the other hand, it has been argued that ships have a

tendency to burn dirty fuel, a result of which is that their

emissions discharge relatively high amounts of pollutants

such as sulphur dioxide. There are also practices such as

“hotelling” during which ships at anchor continue to

run their engines to generate electrical power, though

these are little used in the GLSLS today. As far as air

emissions are concerned, there are opportunities to

switch ships to cleaner fuels. Some progress in this area

should be encouraged in the future. 

Wash, surge and wake: The regular passage of shipping

close to shore has a long-term effect on shorelines,

wetlands, and islands, as well as on species living in the

water. Habitat disturbance results from heavy wake

action and propeller motion causing hydrodynamic

disturbances. Nesting waterfowl are particularly sensitive

to ship wakes, which cause changes in flow patterns, in

wave conditions, in near-shore vegetation patterns, in

turbidity, as well as in substrate and shore profiles. 

For property owners, wakes can cause damage to their

shoreline infrastructure. To a large extent, ship wake

issues were first raised between 1930 and 1962 when the

various locks were constructed and the navigation channels

were dredged to their present configuration. A large

portion of the shoreline affected by wakes has been

armoured with seawalls and riprap. However, there are

many areas where wakes continue to generate turbidity,

erosion and habitat disturbances, most notably along the

St. Lawrence River downstream of Montreal in the

Varennes-Contrecoeur area and along unprotected

reaches of the Detroit and St. Clair Rivers and the St.

Marys River downstream of Sault Ste. Marie. As noted,

one response to wakes consists of hardening the

shoreline with revetment to limit erosion, which can,

however, cause other problems with loss of habitat and

access. The other response is to introduce speed controls

in sensitive areas. Voluntary speed guidelines have been

effective where applied in the St. Lawrence River to

control wakes and their impact on shoreline habitats.

The SLSDC and SLSMC use their Automatic

Identification System /Global Positioning System

(AIS/GPS) vessel tracking system to monitor and

enforce vessel speeds.

Accidents/spills: Accidents and spills, while relatively

infrequent, can have a long-term and spatially extended

impact. In other words, the risk is low but the

consequences can be devastating. Routine discharges,

such as effluent from holding tanks or petroleum

products from bilge discharge can have an incremental

impact on aquatic life. Though there is always a danger

of accidental spills and discharge, it is important to note

that remedial action has been prompt and effective.

Active spill response teams are in place throughout the

system. Moreover, Canada’s Marine Transportation

Safety Board’s recent accident reports show few spills

despite several groundings, and when they do occur,

such spills have been dealt with quickly and with

minimal environmental impact. A less known impact is

associated with the cumulative effect of many small

spills related to transhipments. 

Anti-fouling paints: The use of anti-fouling paints has

resulted in the release of tributyltin (TBT), which is

extremely toxic to molluscs. One effect of TBT pollution

is the development of male sex characteristics in the

females of some species of molluscs, sterilizing populations

of molluscs and eventually leading to local extinction.

Cumulative toxicity can be a particular problem in

docking areas. However, the use of TBT paint is declining

as a growing number of countries, including Canada and

the U.S., prohibit its use. 

While the use of TBT is now regulated under the

Canadian Environmental Protection Act (CEPA) there are

no data on the quantities of TBT used in the aquatic

environment of the study area. Data are also incomplete

on TBT concentrations in water and sediments in the

freshwater portion of the GLSLS. Furthermore, there is

no recognized criterion for the quality of sediments.

However, it is important to note that the shipping

industry has developed and applied economically viable

and environmentally sound substitutes to TBT.

Other impacts: There are a number of other environ -

mental impacts that are attributable to shipping. For

example, cargo ships have displaced and collided with

marine mammals. Noise and vibration have a known

effect on nesting birds and marine mammals as well as

on molluscs and other lake-dwelling organisms. Fish

displacement or heightened activity in winter months

can be harmful but little is known about the effects of

noise on other aquatic organisms. 

Chapter 4

64 Great Lakes St. Lawrence Seaway Study
NIS: The introduction of NIS into the Great Lakes

basin and St. Lawrence River, particularly through

ballast water from trans-oceanic ships, is one of the most

pervasive and challenging environmental problems

facing these waters. Evidence shows that a ship ballasted

with freshwater from overseas sources typically has much

higher numbers of NIS organisms within its hold than a

ship that carries no ballast or that has exchanged its

ballast water with salt water before entering the 

GLSLS system. 

More than 180 species of NIS have been introduced

into the Great Lakes basin and St. Lawrence River

during the past two centuries and at least 85 of these are

reported from the St. Lawrence River. NIS threats exist

from inadvertent introductions through aquaculture, live

fish markets, sport fishing, pet trade, bait fish and garden

plants, as well as from unintentional introductions

through such mechanisms as ballast water discharge by

ships or via interbasin connections, such as the current

concern regarding Asian carp moving toward the Great

Lakes from the Mississippi River via the man-made

Chicago Sanitary and Ship Canal. 

Given the growing recognition of the importance of the

NIS issue, strategies are being put in place to address it.

The most important of these is to prevent ocean-going

vessels from bringing foreign ballast water into the

GLSLS system. This can be accomplished by ballasted

ships exchanging ballast water in the mid-Atlantic and

by non-ballasted ships flushing their holding tanks and

related piping in the mid-Atlantic. The number of

ballasted ships bound for the Great Lakes has fallen over

the past several decades. Vessels that

declare ‘no ballast on board’ (NOBOB)

now account for some 90 percent of all

inbound traffic to the Great Lakes. 

While these practices represent a

positive trend, more work needs to be

done to ensure that vessels entering the

GLSLS system do not serve as vectors 

for the introduction of additional NIS.

The exchange of fresh ballast water with

salt-water is clearly an important

element of ballast water treatment to

prevent NIS introduction, but it is not

100 percent effective. The residue of

unpumpable sludge (water and sediment)

in the bottom of the tanks can still

harbour NIS. Great Lakes and 

St. Lawrence River shippers and federal

agencies, in conjunction with the

International Maritime Organization, 

are working on the development of

appropriate treatment methods to

eliminate aquatic NIS. The “Great Ships Initiative” is a

recently developed industry-led cooperative effort to

resolve the problem of ship-borne NIS in the GLSLS

system. In addition, strong controls are needed to guard

against the movement of NIS through waters

connecting the Mississippi River to Lake Michigan.

Ice breaking

The final navigation-related impact listed in table 4.2 is

ice-breaking. Ice cover plays a significant role in the

physical and biological processes of the Great Lakes and

St. Lawrence River. The ice that forms in early winter

protects the intertidal zones of the St. Lawrence River;

the shores of the estuary would otherwise be severely

eroded by waves generated by violent winter winds. The

opposite occurs at the end of winter: drifting ice during

break-up can transport sedimentary material and erode

intertidal zones and shallow areas. 

Ice breaking activities in the GLSLS system include 

ice clearing in harbours, approaches and connecting

channels near both the start and end of the shipping

season. Situated downstream of Montreal, the St.

Lawrence Ship Channel is kept open for navigation

year-round and therefore has more active ice clearing

and ice management activities. Ice cover provides an

important pathway for wildlife movement across bodies

of water. Ice breaking can upset these important

processes and can directly affect mammals by blocking

their movements across the ice. Ice breaking activities

can also increase propeller wash, drawdown and surge

waves, dislodge or destroy aquatic vegetation and lakedwelling organisms as well

as disturb resting fish or

induce abnormal activity in

them. Though limited in

geographic scope, icebreaking activity can also

alter migratory waterfowl

habitats and their use by

over-wintering birds. 

Environmental Considerations

Zebra mussel and Sea

lamprey (aquatic NIS)

Source: U.S. Environmental

Protection Agency, Great Lakes

National Program Office,

www.epa.gov

Great Lakes St. Lawrence Seaway Study 65
CUMULATIVE EFFECTS

ANALYSIS

Commercial navigation and the infrastructure required

to support it have had a significant environmental

influence on the Great Lakes basin and St. Lawrence

River. Through a review of the environmental stressors

acting upon the various ecosystem components of the

waterway, a qualitative sensitivity assessment was under -

taken. This analysis was performed using a workshop

approach wherein the study team debated and arrived 

at a consensus sensitivity ranking for each stressor. 

A summary of these results is presented in Table 4.3.

This table lists the VECs in columns across the top of

the table and the stressors in rows along the left-hand

side. The check marks indicate a VEC-stressor combina -

tion where significant interactions can occur. In the

rightmost columns of this table, the sensitivity of the

overall ecosystem to a particular stressor is assessed.

The assessment criteria that were used are as follows:

• Areal extent of the stressor. The more widespread the

stressor, the greater the potential impact and the more

difficult it will likely be to mitigate. In the matrix, a

stressor that has an impact at only a local level scores

1, regional level scores 2, and system wide scores 3.

• Temporal extent of the stressor. Many stressors are

short lived or seasonal in duration and this may

reduce the significance of their impact. Alternatively,

the effects of some stressors such as persistent heavy

metal pollution may be very long term. A stressor

with a short term effect scores 1, medium term scores

2, and long term scores 3.

• Reversibility of the effect of the stressor. This is a

subjective assessment of the potential for the effect to

be reversed through the application of mitigating

measures or policy decisions that would limit the

severity of the impact. A high degree of reversibility

scores 1, medium degree scores 2, and low degree

scores 3.

Each of these measures is given a numeric ranking, which

is then summed to provide an aggregate score. This

aggregate score is then used to provide a ranking of

sensitivity to that particular stressor. 

A total of 35 environmental stressors have been identified,

29 (83 percent) of which are deemed to be of high or

medium importance. At the same time,29 stressors out

of 35 (83 percent) fall into the medium or low degree

category of reversibility, meaning their impact cannot

easily be undone. This suggests that the region is quite

vulnerable to the stressors that are present and that

66 Great Lakes St. Lawrence Seaway Study

minor management adjustments are unlikely to result in

appreciable gains in environmental quality. The most

influential non-navigation related stressors at the scale

of the entire basin are climate change, air emissions,

water withdrawals and diversions, and introduction and

transmittal of NIS. Most non-navigation related

stressors will act synergistically with other stressors

affecting aquatic ecosystems.

Navigation related stressors have the greatest number of

interactions with the aquatic ecosystem. The stressors of

greatest concern are local channel modification, water

level management, introduction and transfer of NIS,

infrastructure development, and ship air emissions.

While these five navigation-related stressors are signifi -

cant from a system-wide perspective, other stressors such

as shoreline erosion have serious implications at local or

regional levels and their impacts should be addressed at

the appropriate scale.

FUTURE TRENDS

The traffic trends forecasted by the economic component

of the GLSLS study were used to anticipate the likely

future condition of the VECs. The key economic trend

considered was that the relatively modest changes in

bulk cargoes predicted in the economic forecast would

not result in substantial changes to trade patterns

(origin-destination routings) nor to shipping services

(vessel size and type) up through 2020. Over the longer

term, socio-economic structural changes could modify

these patterns. It was assumed that the potential growth

of shortsea shipping would generate an increase in crosslake and internal system traffic. 

Climate change: Changes to the climate are projected

to reduce water levels throughout the Great Lakes in the

coming 50 years. A reduction of 4 to 24 percent in net

water supply may lead to a drop in water level of

between 26-112 cm (10-44 in) in Lakes Huron and

Michigan, which would have an important impact

downstream. The impact on Lake Superior would be

about half of that level while the potential effect on

Lake Ontario is unknown because of water-level

regulation. Depending on the pattern of regulation and

capacity to manage extreme climatic situations, the

impact on the St. Lawrence River may be reduced or

increased. Changes in water level caused by climate

change would have their greatest environmental effects

on wetlands, coastal and riverine habitats. A rise in the

sea level would increase water levels in the St. Lawrence

estuary and river accompanied by a landward (upstream)

migration in the salt-fresh water interface. The tidal

change may be more important than migration from

saltwater and this would likely have a major impact on

Chapter 4
Great Lakes St. Lawrence Seaway Study 67

Environmental Considerations

TABLE 4.3

Stressor analysis

Air quality1

Soil and ground water

Vegetation2

Fauna3

Special features4

Water and substrate5

Flora/wetlands6

Aquatic fauna7

Areal extent 

Temporal extent 

Reversibility 

Low 

Medium 

High

Class of stressor Stressor 34567 8 9

Global Climate change ✓✓✓✓✓✓✓ 333 9

Water withdrawal & diversions ✓ ✓✓✓ 333 9

Introduction & transfer of aquatic NIS ✓✓✓ ✓✓ 333 9

Air emissions ✓ ✓✓ ✓✓✓ 332 8

Industrial/municipal effluent ✓✓✓✓✓ 232 7

Solid waste disposal ✓ ✓ 133 7

Landscape fragmentation ✓✓✓ ✓✓ 232 7

Runoff ✓ ✓ ✓✓✓ 222 6

Shoreline alteration/hardening ✓✓✓✓✓✓✓ 132 6

Noise & vibration ✓ ✓ 132 6

Erosion and sedimentation ✓✓ ✓✓✓✓ 122 5

Introduction & transfer of aquatic NIS ✓ ✓ 333 9

Shoreline alteration/hardening ✓✓✓✓✓✓✓ 122 5

Waste disposal/pollution ✓ ✓✓✓ 121 4

Erosion and sediment re-suspension ✓ ✓✓✓✓ 121 4

Wildlife conflicts ✓ ✓ 1113

Channel modification ✓✓✓✓ 133 7

Dredge material placement ✓✓✓✓✓✓✓ 132 6

Shoreline alteration/hardening ✓✓✓ ✓✓✓ 132 6

Maintenance dredging ✓✓✓ 122 5

Water management for all purposes ✓✓✓✓ 332 8

Infrastructure development ✓✓✓✓ ✓✓✓ 133 7

Facility maintenance ✓ ✓✓ ✓✓✓ 132 6

Uncontrolled releases ✓✓ ✓ ✓✓✓ 122 5

Introduction & transfer of aquatic NIS ✓✓✓ 333 9

Ship’s air emissions ✓ ✓✓ ✓✓✓ 232 7

Biocides (antifouling) ✓ ✓ 132 6

Accidents/spills ✓✓✓✓ 222 6

Noise & vibration ✓ ✓ 113 5

Waste disposal ✓✓✓ 122 5

Prop wash, surge and wake ✓✓✓✓ 122 5

Cargo sweeping ✓ ✓ 121 4

Groundings/anchoring ✓✓✓ 1113

Wildlife encounters ✓ 1113

Ice breaking ✓✓✓✓✓ 2 2 2 6 

Non-navigational related Navigational related 

Development 

and land use 

Air Terrestrial

systems 

Aquatic

systems Sensitivity ranking 

Valued ecosystem component 

Water-based 

recreation and 

tourism 

Channel & port

maintenance 

Water management 

Land-based support

activities 

Ship operations 

1 Nox, SOx, CO2, CO, Particulates

2 Limited to nearshore upland vegetation

3 Terrestrial fauna, excluding aquatic/shore birds 

4 Islands 

5 Quality and quantity 

6 Submergent and emergent (wetlands), phytoplankton 

7 Fish, marine mammals, benthic invertegrates, zooplankton,

amphibians, aquatic/shore birds 

Sensitivity rankings 

Areal extent Temporal extent Reversibility 

1 Local 1 Short 1 High 

2 Regional 2 Medium 2 Medium 

3 System 3 Long 3 Low 
wetland habitats such as those of Lake St. Pierre.

Increased temperatures would alter species habitats and

could reduce levels of oxygen dissolved in the water.

Warmer conditions may also reduce the duration of ice

cover throughout the region which, in turn, can increase

evaporation and reduce the need for ice breaking.

Changes in ice cover may also disrupt fish and mammal

behaviour.

Air Quality: Air quality is best in the upper lakes and

deteriorates in the more populated and heavily industri -

alized lower lakes. With continued growth in the basin,

overall emissions will likely grow, despite improvements

in emission controls. One result may be an increase in

the number of smog alerts or longer periods of bad air

quality, especially in the downtown areas of major cities

or in some ports.

Various measures are being taken to reduce polluting

emissions, but the rate of decrease is anticipated to be

significantly less for the marine sector than for the

overall transportation sector. Currently, marine trans por -

tation represents almost 40 percent of the SOx emissions

attributable to the entire transportation sector. This is

mainly due to the relatively poor quality of marine fuel

compared to fuels used in other modes of transportation.

Even so, according to Environment Canada,2 the trans -

portation sector is responsible for only 4 percent of total

Canadian SOx emissions: the vast majority of SOx

emissions come from the oil and gas industry (22 percent),

electric power generation (27 percent) and mining and

smelting operations (33 percent).

Wetlands: Wetland protection policies have slowed the

rate of wetland loss, but wetlands will remain under

pressure. Increasing nutrient loads, decreasing water

levels and higher temperatures are all negative factors,

leading to the potential for continuing loss of wetland

diversity as well as increases in the frequency and extent

of algal blooms and anoxic conditions at the end of the

summer and beginning of autumn.

Islands: Islands will continue to provide important

habitats for fish and wildlife including both nesting

colonial birds and migratory birds. Future development

pressure will combine with any potential increases in

ship traffic to exert continued pressure on islands,

though it is likely that the major impact on islands will

be felt from the pressures of urbanization.

Water quality is expected to improve over the coming

years in terms of many types of contaminants as the

standards and availability of waste water treatment

continue to increase. There is uncertainty, however,

regarding the capacity and ability of existing treatment

plants to cope with new and emerging contaminants.

While increased ship traffic could bring a commensurate

increase in water quality deterioration due to spills and

leakages, such negative impacts will often be short-lived

and localized, particularly compared to urban, industrial

and agricultural water quality degradation.

Fauna: Increases in shipping will increase stress on

aquatic fauna exposed to the effects of erosion and

shipping activities in confined waterways. Measures

directed at improved treatment of ballast can reduce the

danger of new NIS introduction. The NIS already

introduced, however, will continue to spread, altering

both the structure and functioning of the aquatic

community. 

Chapter 4

2 http://www.ec.gc.ca/cleanair-airpur/Main_Emission_Sources-WS0D5AD9F6-1_En.htm

68 Great Lakes St. Lawrence Seaway Study

Lotus-in situs, Lake Michigan

Source: U.S. Environmental Protection Agency, Great Lakes National Program

Office, www.epa.gov
MANAGING THE

ENVIRONMENTAL

IMPACTS OF NAVIGATION

Assessment systems

U.S. and Canadian environmental assessment legislation

provide for rigorous assessments of impacts of proposed

projects and can include impact mitigation measures to

be part of any approval. While this legislation provides a

solid foundation for assessing environmental impacts, most

ongoing operations, maintenance and repair activities

envisioned in the GLSLS Study would not require further

assessment under these federal regimes, though some state

or provincial assessments might apply. If the GLSLS

Study or follow-up work should result in a recommendation

to the Cabinet (Canada) or a federal agency (U.S.)

regarding how best to ensure the continuing viability 

of the GLSLS system, it is possible that a Strategic

Environmental Assessment (Canada) and/or

Environmental Assessment or Environmental Impact

Statement (U.S.) may be required as part of the process

of approving any proposed investments. 

Current environmental

management actions

Many of the environmental pressures presently facing

the system are well-known and a wide range of practices

and policy initiatives are either in place or in the process

of being implemented. For example: 

• Speed limits have been established in narrow channel

areas to reduce shoreline erosion and to improve

safety of operations;

• Safety measures and draft advisories are in place to

respond to water level changes and reduce the

potential for grounding and bottom disturbances;

• Minimum fuel quality standards have been set to

reduce ships’ emissions; 

• Port regulations control anchoring, waste management

and other operational practices while in port;

• Anti-fouling paint using Tributyltin (TBT) has been

banned in Canada and the U.S. in response to

toxicity concerns; 

Great Lakes St. Lawrence Seaway Study 69

• Programs have been established to monitor changes

to wetlands. Not all wetlands have been catalogued,

however, and improvements to the cataloguing

methodology will provide more accurate estimates of

wetland boundaries;

• To reduce the likelihood of introducing new NIS,

ballast water management has received considerable

attention, as described in detail further below.

While the preceding actions represent individual

initiatives, there are also examples of comprehensive

strategies aimed at promoting environmentally

sustainable navigation. One of these is the Sustainable

Navigation Strategy for the St. Lawrence River. This

cooperative initiative involves the commercial and

recreational boating industry, the governments of

Canada and Quebec, environmental groups and riverside

communities. It is presently the most comprehensive

strategy dealing with the impacts of navigation and

focuses on consensus building and communications,

planning, research and development. Among the issues

it has addressed are dredging, adaptation to water level

fluctuations, shoreline erosion, sewage and ballast water

management, and the risks of hazardous product spills.

Another example of stakeholder involvement in

addressing navigation-related environmental concerns is

the U.S. St. Marys River Winter Navigation and Soo

Locks Operations Memorandum of Agreement This is a

multi-agency agreement to protect some 5,400 hectares

(13,300 acres) of Michigan’s coastal wetlands through

the implementation of a winter navigation agreement

that fixes operation dates, speed limits and monitoring

responsibilities. Broader environmental initiatives, such

as lake-wide management plans on all the Great Lakes

and the St. Lawrence River Action Plan downstream,

are directed at fostering environmental sustainability. 

Measures to control the effects 

of ballast water

Responding to the NIS challenge, both government and

industry have sought to implement measures that would

regulate ballast water. In Canada, the first guidelines to

address ballast water management were developed in

1989 and strengthened in 2000. At the same time, the

Shipping Federation of Canada adopted a Code of Best

Practices for Ballast Water Management and members 

of the industry were involved in consultations on the

development of Canadian regulations. In 2001, the

American Lake Carriers Association (representing the

U.S. laker fleet) and the Canadian Shipowners Association

(representing the Canadian laker fleet) adopted voluntary

management practices to reduce the transfer of nonindigenous invasive species within the Great Lakes. 

Environmental Considerations
In the following year, they were incorporated into the

joint practices and procedures mandated by the Canadian

St. Lawrence Seaway Management Corporation and the

U.S. Saint Lawrence Seaway Development Corporation

for transit of the Seaway system.

In 1993, the U.S. established ballast water exchange

regulations pursuant to the 1990 Non-indigenous Aquatic

Nuisance Prevention and Control Act. These regulations

were amended in 2004 to make reporting mandatory for

all shipping in U.S. waters, and again in 2005 to make

ballast water management mandatory in all American

waters. As of 2003, Canada did not prohibit the discharge

of ballast water within its 200-mile exclusive economic

zone. But in 2006, Transport Canada published regulations

making it mandatory to follow several of the measures

outlined in the Department’s Publication Guidelines for

the Control of Ballast Water Discharge from Ships in Waters

under Canadian Jurisdiction (TP 13617). The Canada

Shipping Act, 2001, which entered into force in 2007, is

expected to further enhance the Canadian regulatory

regime by extending the current authority available to

regulate the prevention of introductions of aquatic

invasive species by ships. The regulations apply to ships

that take on local ballast water if that ballast water is

mixed with other ballast water that was taken on board

the ship outside waters under Canadian jurisdiction,

unless the other ballast water was previously subjected 

to exchange or treatment. The regulations also include

provisions relating to international NOBOB ships

entering waters under Canadian jurisdiction.

Practices for treatment of ballast water clearly exist, and

new technologies are being developed and tested. These

have to be coupled with comprehensive regulatory and

monitoring systems to ensure that best practices are

followed and that action is taken in due time.

Ongoing monitoring

Many of the measures already in place have to be

thought of as only the beginning of a long-term and

ongoing process of environmental management. In the

future, the operation and maintenance of the GLSLS

system will have to be accompanied by ongoing

monitoring of seven key issues: 

• Controlling the introduction and transmittal of NIS;

• Addressing the social, technical and environment

impacts of long-term declines in water levels

including right-sizing the infrastructure;

• Minimizing the impact of ship emissions;

• Ensuring that dredged materials are placed in an

environmentally responsible manner;

70 Great Lakes St. Lawrence Seaway Study

• Protecting islands and narrow channel habitats from

the effects of ship passage;

• Minimizing the re-suspension of contaminated

sediments; and

• Managing the impacts of ships’ grey and black water

and bilge waste.

There have been considerable resources devoted to

research and planning but, with the exception of some

specific areas related to NIS, there have been few

initiatives that have seen “on-the-ground” changes.

Impacts related to planned works, such as maintenance

of infrastructure, maintenance dredging and placement

of dredged material can be minimized through effective

application of environmental assessments, remedial

actions, sound environmental management strategies

and best practices.

Other stress-related changes pose greater challenges.

The rate at which new NIS are identified may be too

slow, allowing them to become established and expand

through the system before they are discovered. Also, NIS

may expand and colonize in freshwater environments as

well as in estuarine environments such as the Mitten

Crab recently discovered in the St. Lawrence River, and

be able to colonize both environments. 

The loss of wetlands may be accelerated by climate

changes that reduce water levels. Such changes will be

keenly felt in shallow and narrow channel areas. In

addition, reductions in water levels may result in pressure

for more dredging and suitable dredged material place -

ment sites will become increasingly scarce. 

Numerous measures have been identified by various

environmental interests throughout the region that, if

implemented, could have a beneficial impact, though

any evaluation of their technical feasibility, social

acceptance and cost effectiveness was deemed outside

the scope of the present GLSLS Study. Consequently,

more work is needed around protection measures and

new technologies that can reduce or halt further eco -

logical deterioration from navigation-related stressors.

Environmental management systems are needed in many

areas to ensure that environmental stewardship is built

into standard operating procedures. Finally, monitoring

of shipping practices and enforcement of regulations 

will be an important part of any future impact mitiga -

tion strategy. 

Chapter 4
CONCLUSIONS

The overall health of an ecosystem reflects the cumulative

effect of all the stresses to which it is exposed. The

ecosystems of the Great Lakes basin and St. Lawrence

River are under enormous pressures from a wide variety

of sources. The GLSLS navigation system represents an

additional stressor in this complex mix. Taking stock of

the environmental impact of navigation on the system

turns up a mix of positives and negatives. 

Marine transport of bulk goods is safer and may be more

fuel efficient than the alternatives of road and rail

transport, especially with regard to the emission of

greenhouse gases. Statistics indicate that the risk of

accidents and spills with marine transport is significantly

less than for either road or rail transport. Marine

transport also offers relief to urban congestion and the

associated pressure this congestion exerts on public

infrastructure.

However, non-indigenous invasive species are an

enormously disruptive force on basin ecosystems and

shipping is a major vector for the transportation of NIS.

The operation of the navigation system in some areas 

is associated with the regulation of water levels, which

has reduced the range of water level fluctuations and

adversely affected biodiversity. Ship wakes can erode

shorelines and wetland habitats, increase turbidity and

trigger the propagation of man-made shore protection,

which further disturbs the natural shoreline. The fuels

burned by most ships are high in sulphur and particulates

leading to unnecessary air pollution. Dredging activities

in support of marine navigation can result in deterior -

ation of water quality and disruption of the environment.

Even though the risk of accidents and spills is lower

than for road or rail transport, impacts could still 

be significant.

In practical terms, many of the navigational impacts

described in this chapter have already occurred and

cannot be easily reversed. Where impacts continue,

however, regulations should be introduced to reduce

their severity. 

Over the past 20 years, the industries that use the GLSLS

and the agencies responsible for the GLSLS have taken

up the role of environmental stewardship. The interagency collaboration between groups such as Environment

Canada, the U.S. Fish and Wildlife Service and the

regulatory and operational agencies of the GLSLS system

needs to be continued and further fostered. Regulations

and codes of practice have been implemented to mini -

mize many of the environmental impacts mentioned

above. That said, much more needs to be done. New

technologies for ballast water treatment and other NISrelated issues need to be developed and implemented.

Current initiatives, such as the Asian Carp Barrier in

the Chicago Sanitary and Ship Canal and sea lamprey

remediation programs, focused on dealing with NIS,

should continue as well as the development of a compre -

hensive plan to address the inadvertent introduction

and transmittal of NIS. Ships need to use cleaner fuels

and adopt emission-reducing technologies. Ship wake

problems need to be assessed as an integral part of

waterway management, particularly in addressing how

changes in navigation and/or ship characteristics can

affect the environmental impact of wakes. 

Through continued diligence in this area, society can

capitalize on the environmental benefits offered by

marine transportation within the GLSLS, while reducing

the environmental impacts of navigation.

Environmental Considerations

Great Lakes St. Lawrence Seaway Study 71
72 Great Lakes St. Lawrence Seaway Study

Chapter 4
CHAPTER 5

Maintaining the Infrastructure

While the infrastructure of the Great Lakes St. Lawrence Seaway

system continues to provide reliable service, the age of the 

infrastructure has reached and or exceeded its original design life. 

The likelihood that any one of its hundreds of different components will

fail increases with each passing year. To maintain operational integrity,

an analysis of maintenance needs has been performed that takes 

into account the current condition of the lock systems and associated

infrastructure on which navigation depends, the probabilities 

that certain components will fail, the costs of such failures 

and their likely impact on navigation, the costs of maintenance, 

and the earliest practical timing for repairs and maintenance 

to ensure the continued high level of system reliability. 

The analysis incorporates both the expected economic benefits 

arising from the continued operation of the system as well as 

the potential environmental impact associated with some 

maintenance activities. The result is a planning tool that can be used 

to help inform the development of maintenance strategies.
The age of the infrastructure of the Great Lakes 

St. Lawrence Seaway (GLSLS) system is 75 years for the

oldest components. The Montreal-Lake Ontario lock

components in the St. Lawrence River date back to

1959. The Welland Canal locks date back to 1932. 

At the Soo Locks, the Poe Lock was opened for naviga -

tion in 1969, while the MacArthur Lock has been in

operation since 1943. The age of these components, along

with their exposure to infrastructure stressors including

winter conditions, means that they have experienced 

a significant amount of wear and tear. As a result, a

considerable amount of effort is devoted to maintaining

the system at its current operational level. Where and

when to deploy that effort is a major decision that has 

a direct impact on the overall efficiency and hence

viability of the GLSLS system. 

The Engineering Working Group was mandated to

examine the current condition of the GLSLS system’s

infrastructure and to examine approaches toward its

ongoing maintenance necessary to ensure the continued

high level of system reliability. To carry out this objective,

the working group started with a thorough examination

of the current condition of the lock systems and their

associated components. Each of its key elements was

evaluated in terms of its importance to the operations of

the system, the likelihood of its failure, the consequences

of its failure, and the costs of keeping it operational. 

An important aspect of this analysis is that it was

undertaken on a system-wide basis. All infrastructure

components on both sides of the border have been

assessed using the same techniques and evaluated against

the same standards. The working group was able to

assess the reliability of individual lock components and,

more importantly, it integrated all these components

into a system-wide reliability analysis that identified

maintenance and rehabilitation priorities across 

the system. 

SYSTEM INFRASTRUCTURE

Though the GLSLS system is conventionally thought of

as a series of locks, its locks are actually part of a much

more elaborate transportation system that includes not

only the lock chambers, but also bridges and tunnels,

and the channels that link the locks together. Each of

these has a distinctive function in the seamless operation

of the overall navigation system and each has specific

operational and maintenance requirements.

74 Great Lakes St. Lawrence Seaway Study

The locks

As was highlighted in the system overview included in

Chapter 2 of this report, the GLSLS system includes

navigation locks located at 16 different sites throughout

the St. Lawrence River, Welland Canal and St. Marys

River. These locks allow vessels to bypass the rapids and

falls throughout these rivers, and serve to raise and

lower the vessels in order to overcome the water surface

elevation differentials encountered. 

Figure 5.1 displays how these locks are operated to raise

or lower a vessel.

Chapter 5

FIGURE 5.1

How navigation locks operate
While the basic operating principle of these locks

appears to be fairly straightforward, in actuality each one

of the locks is comprised of a myriad of structural,

mechanical and electrical components required to

facilitate this operation. As such, the locks of the

GLSLS system constitute its costliest and most critical

components. 

Each individual lock includes numerous components,

including:

Approach and guide walls: These structures are typically

comprised of concrete monoliths or a combination of a

concrete cap supported by either rock filled timber

cribbing or rock filled steel sheet pile cells. These

structures help to align the vessels as they approach the

lock and guide the vessels into the lock chamber. These

walls also provide a location where vessels can tie-off

while awaiting entry to a lock chamber.

Lock chambers: These structures are comprised of

concrete monolith walls and either concrete or rock

floors. There are concrete culverts running in either the

walls and/or floors through which the water flows during

emptying and filling of the lock chamber, and within

which are located the emptying and filling valves used

to regulate flow. There are also numerous cut-outs,

openings and galleries located throughout the chamber

to house mechanical and electrical operating machinery,

and for placement of stop logs. 

Lock gates: Generally large steel miter gates which open

to allow vessels to enter or exit the chamber, and which

close to hold back water to allow levels within the

chamber to be raised or lowered. As the name suggests,

these gates form a mitered angle when closed. Steel

sector gates are also used at the upstream end of the

Montreal Lake-Ontario segment of the Seaway where

the pool differential is only of the order of magnitude of

1 metre (3.28 feet) and at other sites to allow closure of

the gates against the full pool differential should the

miter gates be so damaged that water level control

would be lost. Miter gates use the difference in water

levels across the gate to provide the force required to

achieve a nearly water-tight seal. Typically, lock lifts in

the GLSLS range from 6.4 m (21 ft) at the Soo Locks to

15 m (49.2 ft) at the Welland and Montreal-Lake

Ontario locks. Generally, the upper and lower lock gates

are of different heights. The upper gates range in height

from about 10 to 11 m (32.8 to 36 ft), whereas the 

lower gates are higher by the pool differential, which is

the difference in the level of water upstream and

downstream of the locks.

Maintaining the Infrastructure

Lower miter gate at Eisenhower Lock

Source: Saint Lawrence Seaway Development

Corporation

Great Lakes St. Lawrence Seaway Study 75

This massive gate must be capable of maintaining

a nearly water-tight seal. At the same time it needs

to be opened and closed on a routine basis.

The gate itself is typically formed by a set of

horizontal girders sitting within a frame.

Diagonal bracing is used to provide additional

rigidity.

Vessel being raised in the lock chamber

Source: The St. Lawrence Seaway

Management Corporation
The photo on page 75 shows the lower miter gate at the

Eisenhower Lock viewed from the downstream side.

These gates are massive and have to be capable of

maintaining a nearly water-tight seal. At the same time

they need to be opened and closed on a routine basis.

The gate itself is comprised of two miter gate leaves and

is typically formed by a set of horizontal girders sitting

within a frame. The alignment and rigidity of the gate is

essential to ensuring its smooth operation. Diagonal

braces are used to provide additional rigidity. The gate

leaves rest on a pintle system (essentially a ball and

socket) at the base of the gate leaves and are secured to

the lock wall at the top of the gate leaves. 

The seal between the two miter gate leaves and the

joint between the gate leaves and the lock wall (at a

recess or quoin) both need to be watertight. Both the

quoin and miter blocks are subject to wear and need to

be changed when either the seal has deteriorated or

there is excessive deformation and stressing of the gate.

Safe and reliable operation of navigation locks requires

that systems be in place to provide backup should one 

of the lock gates fail either because of wear and tear or

because of ship impact. Some of the locks are equipped

with redundant gates that can be brought into operation

should the main gates fail. Other locks have spare gates,

but changing out a failed gate requires a significant

amount of time and energy. Some of the locks have

dewatering gates upstream and downstream of the main

gates to facilitate dewatering and servicing of the gates.

Other locks use stoplogs, which can be lowered into

place to allow for dewatering. 

Stoplogs: These steel structures can be used to form a

temporary barrier placed across the lock, typically both

upstream of the upper gate and downstream of the 

lower gate, to allow dewatering of the lock chamber for

maintenance and repairs. Stoplogs used throughout the

GLSLS system consist of a series of steel plate girders that

are lowered into slots in the upstream and downstream

walls of the lock. Placement of the stoplogs requires a

large derrick crane and many of the lock facilities have

stiff-leg derrick cranes for this purpose.

Valves: Lock operations require a large array of

mechanical components, including numerous valves 

for control of water. Culvert valves are opened and

closed during each locking cycle to fill and drain the

lock chamber. These valves are actually large steel 

gates located within the concrete culverts which are

raised and lowered to control flow of water through 

the culverts.

Other mechanical & electrical machinery: Ongoing

safe and efficient operation of the lock systems relies on

a wide range of additional components. Control systems

and motors are required to operate the machinery of 

the lock gates, valves and lift bridges. Many of these

functions are still being performed with original

equipment installed as part of initial construction of the

locks. Some of these components have already been

upgraded, others are in need of an upgrade. All of the

locks throughout the GLSLS are equipped with similar

ship arrestors. These are heavy cables strung across the

lock in front of the lock gates prior to a ship entering

the chamber. Should the ship lose control for any

reason, the arrestors are designed to stop the ship before

it can strike the lock gate.

Bridges, roads and tunnels

The GLSLS navigation system is crossed by numerous

bridges, both fixed and moveable, as well as by tunnels at

certain locations. Both bascule and vertical lift bridges

are raised to allow for the passage of ships. At the

Eisenhower Lock on the Montreal-Lake Ontario section

of the system, access to the Moses-Saunders hydropower

generating system is provided for via a highway tunnel

passing through the upper lock sill. The maintenance 

of many of these crossing structures falls under the

jurisdiction of the same organizations responsible for

operation and maintenance of the locks. In the case of

the Welland Canal, these bridges are all owned by

Transport Canada and operated by the St. Lawrence

Seaway Management Corporation (SLSMC). Bridge

controls for several of the vertical lift and bascule

bridges over the Welland Canal were recently auto -

mated and are now remotely controlled. The bridges’

electrical power and control systems were all upgraded 

at the same time.

Navigation channels

Navigation channels are maintained in the St. Marys

River, the St. Clair River and Lake St. Clair, the Detroit

River and the Lake Erie entrance to the Welland Canal

as well as at various locations along the St. Lawrence

Seaway. The nominal allowable vessel draft has been as

high as 8.08 m (26.6 ft) depending on available water

levels for the St. Lawrence Seaway, and 7.77 m (25.5 ft)

for the Upper Great Lakes waterway (as controlled by

the Soo locks and the St. Marys River navigation

channel). 

Chapter 5

76 Great Lakes St. Lawrence Seaway Study
The U.S. Army Corps of Engineers (USACE), and the

Saint Lawrence Seaway Development Corporation

(SLSDC) to a much lesser extent, undertakes some two

to four million cubic metres (three to five million cubic

yards) of maintenance dredging annually within the

Great Lakes Basin. This includes maintenance dredging

for 47 deep draft ports, 55 shallow draft harbors and

maintenance of some 1,200 kilometres (745 miles) of

navigation channels. Many of the major ports served by

the GLSLS system also require significant maintenance

dredging on a routine basis. At the Port of DuluthSuperior, 80,000 cubic metres per year (100,000 cubic

yards per year) of regular dredging is required just to

maintain the status quo. Maumee Harbor (Port of

Toledo) requires a minimum of 650,000 cubic metres per

year (850,000 cubic yards per year) of dredging. An

additional 230,000 cubic metres per year (300,000 cubic

yards per year) would be needed over the next nine

years to clear an existing backlog in maintenance

dredging. This type of routine maintenance dredging is

carried out for these port facilities by the USACE as

federally-authorized navigation projects.

There are additional areas, including the Seaway 

canals, that require maintenance dredging by the

SLSDC and SLSMC.

INFRASTRUCTURE

STRESSORS

The various infrastructure components

of the navigation system are subjected to

an array of stressors that contribute to

the overall degradation of the condition

of these com ponents over time. The

majority of these stressors can be

associated with the day to day passage of

vessels, and are typically either a result

of wear and tear from vessel movement

or wear and tear from the cyclical

operation of the various mechanical

components (gates, valves, bridge

machinery, etc.). In addition, there are

certain stressors unique to the GLSLS

system due to its geographic location

(freeze-thaw cycles, ice loads), and

associated with the original construction

of the structures (construction quality,

impacts associated with changes in

vessel operations).

Vessel movement impacts: Over time concrete can

degrade due to abrasion from ships as they rub against

approach walls, guide walls and lock chamber walls. 

In addition, these structures are often subject to vessel

impacts as these large freighters attempt to navigate into

and out of the lock approaches and chambers. Lock

gates can sometimes also be subject to minor impact by

vessels when entering the lock chamber.

Cyclical operation impacts: Each time a vessel transits a

lock, the lock operating machinery is subject to a cycle

of operation (gate movement, ship arrestor raising,

culvert valve movements, etc.). This continual cycling

of these lock components results in long term wear and

tear and the ultimate degradation of the condition of

these components. Lock cycles not only result from

passage of commercial vessels, but also from passage of

maintenance fleet vessels, recreational craft, tour boats,

as well as operations needed to routinely pass ice during

winter and spring. The moveable bridges spanning the

navigation system are also subjected to this cyclical

operation.

Excessive wear of components can ultimately result in

the cracking of steel members due to fatigue. In the case

of a lock gate, cracking to the extent that plastic

deformation occurs might indicate that some of the steel

gate components have been over-stressed resulting in an

irreversible (‘plastic’) deformation and can be an

indicator of potential structural problems. 

Maintaining the Infrastructure

Raising of lift bridge during vessel transit

Source: Thies Bognor, photographer

Great Lakes St. Lawrence Seaway Study 77
Cold weather operation impacts: Because of

the geographic location of the system, the

infrastructure is subject to an additional set

of stressors associated with sub-freezing

temperatures. Concrete structures are subject

to freeze-thaw cycles that cause cracking and

spalling of the surface as well as corrosion of

the reinforcing steel underneath the surface.

Passage of ice early and late in the shipping

season results in additional abrasive forces on

lock walls and can produce additional forces

on gates and valves.

Other factors: There are a number of

additional stressors acting on infrastructure,

the most critical of which is an AlkalineAggregate Reaction (AAR) that is present

within the concrete structures at several of the locks

located in the Montreal-Lake Ontario corridor of the

system. This condition is causing the concrete to expand

over time, resulting in misalignment of lock machinery

and a gradual narrowing of the lock chambers. This

condition also results in cracking of the concrete as a

result of the separation of the aggregate from the cement

mortar. This condition is resulting in as much as a 

2.5 centimetres (1 inch) narrowing of the affected locks

every five years. The impact of this narrowing is

compounded during early winter and early spring

operations when ice is also present.

78 Great Lakes St. Lawrence Seaway Study

In some instances, the original design and construction

of the infrastructure has been subjected to operational

conditions associated with changes in vessels and vessel

operations which have resulted in accelerated

degradation. 

The MacArthur Lock upper approach wall at the Soo

Locks was built in the 1940s with mixed construction

types, including mass concrete gravity monoliths

founded on rock as well as monoliths founded on timber

cribbing. The approach channels were excavated into

the underlying bedrock. The underlying rock ledge is

composed of the local sandstone bedrock which is

interlayered with silt bands. Movement of the concrete

Chapter 5

North Lock Wall at Snell with Vertical

Wall Armor. (Note typical damage at

monolith vertical joints)

Source: Saint Lawrence Seaway

Development Corporation

Concrete lock wall surface deterioration at Welland Canal Lock #7 

(note exposed rebar at damaged area)

Source: The St. Lawrence Seaway Management Corporation
wall has occurred and is attributed to erosion of the

underlying rock ledge. This erosion has been accelerated

by the use of ship bow thrusters, which have been used

during maneuvering since about 1975. 

The timber pile tie-up walls at the Welland Canal were

built in the late 1950s as an extension of the existing

concrete lock approach walls. They provided for

securing vessels close to the locks and thus allowed two

vessels to pass each other much closer to the lock than

would otherwise be possible. These walls were further

extended in the mid 1960s when it was anticipated that

a new canal would be needed, and as such, the walls

were deemed to be temporary and designed for only 

25 years. There has been much damage to the walls 

over the years from ship impacts both at the fender level

and from bulbous bows below water. In some areas,

instability of the sloped bank behind has affected the

walls and sections have been replaced. The timber piles

are also deteriorating and there is an ongoing program of

repairs to piles and beams. In many areas the timber

decks have shrunk leading to loss of fill material, which

has to be replaced constantly. 

Navigation channel maintenance factors: Navigation

channels require periodic maintenance dredging to

maintain their authorized depths. Vessel drafts, however,

depend on water levels which vary both by season and

long term. Climate change modeling indicates that

overall lake and river levels within the GLSLS are on a

downward trend associated with long-term predictions of

the various natural factors which influence lake levels.

Since the elevations of the lock chambers and sills are

fixed and navigation channel depths limited to

authorized depths, a long-term reduction in lake levels

would reduce the available draft for shipping which

would, in turn, lead to reduced vessel carrying capacity

and increased vessel transits. A long-term reduction in

lake levels could also result in changes to harbor

sedimentation patterns and, potentially, an increased

need for dredging. In addition to the potential increase

in maintenance dredging, disposal of the dredged

material is becoming a significant challenge with tighter

environmental restrictions and an ever decreasing

availability of disposal facilities. 

Great Lakes St. Lawrence Seaway Study 79

CURRENT CONDITION OF

THE INFRASTRUCTURE

One of the primary goals of the GLSLS study was to

conduct a systematic engineering assessment of the

overall infrastructure in order to determine the longterm investments needed to keep the system safe,

efficient and reliable. It should be noted that the

condition assessment and subsequent engineering

analyses focused primarily on the physical infrastructure

components directly related to transiting commercial

navigation. There are numerous additional assets at each

of the lock facilities throughout the system which also

require significant operation and maintenance costs that

are not necessarily directly related to the day to day

transiting of commercial vessels. 

On-site infrastructure inspections were conducted for

each of the major lock systems: the Soo Locks, the

Welland Canal, and both the U.S. (SLSDC) and

Canadian (SLSMC) locks of the Montreal-Lake Ontario

system. The objective was to present a general picture 

of issues such as wear, steel aging, redundancy, and

problems with concrete, as well as to categorize the

outstanding maintenance issues affecting the system 

and to develop a system-wide set of main tenance

requirements with associated cost schedules. To ensure a

uniform and consistent assessment, the same technical

team participated in the inspections and reporting for all

lock systems. In all, a total of 160 separate components

were analyzed ranging from massive concrete lock

chambers and gates to the electrical controls for

operating the machinery. 

On the basis of this review, an infrastructure criticality

index was developed to quantify risk (potential loss) 

and the relative importance of the maintenance work

needed for major engineering components and features.

The index reflects a combination of the physical condi -

tion, the importance to navigation, and the redundancy

associated with each component. The same engineering

team members who conducted the infrastructure

inspections undertook this comparative ranking process. 

Ranking involved a combination of distinct factors:

the current condition of the component, the availability

of backup and/or replacement parts, the likelihood of

future problems occurring with this component, the

relative cost of replacement or upgrading, the impact 

on navigation, and the impact on other services. This

ranking system was then used to identify the more

critical infrastructure components that should be

prioritized for detailed reliability analysis. 

Maintaining the Infrastructure
Chapter 5

THE CRITICALITY INDEX

The Engineering Working Group developed a systematic way of determining the most critical infrastructure throughout the GLSLS

system. A numerical rating system was used to measure the criticality of each component in several categories relative to one another. 

A weighted sum of these ratings was used to determine the most critical infrastructure. To ensure consistency across the entire system,

the same multi-disciplinary team of engineers from SLSMC, SLSDC, and USACE that did the GLSLS inspections also undertook

this criticality analysis. The following rating categories were used in this analysis:

Decision Already Made This category is the only non-numeric ranking. A ‘yes’ indicates that the component was recently 

to Replace/Upgrade replaced or significantly upgraded or that a formal decision has been made to replace/upgrade the

component. In this case, numerical ratings of redundancy, etc. will not be done for the component. 

The term “recently” reflects a replacement or upgrade that is within the first 1/3 of the expected service

life of that component.

Redundancy 1. Component has no redundancy. No means or back-up component can perform the intended

function of the component.

2. Component has back-up or spare part. It will take over two weeks to put in place.

3. Component has back-up or spare part. It will take up to two weeks to put in place.

4. Component has back-up or spare part. It will take between 1 hour and 3 days to put in place.

5. Component is highly redundant. Immediate placement (less than 1 hour) or other measures

available to perform the same function.

Current condition 1. Poor or Failed. Component is currently in a condition that is “failed” or in very poor condition.

Component is not serviceable or is anticipated to become non-serviceable in the very near future.

2. Serviceable. Component requires a significant level of investment above normal maintenance levels

in order to stay operational or component currently provides only limited serviceability due to its

current condition.

3. Serviceable. Component provides adequate service. No known major problems with the structure

that can not be addressed without normal maintenance.

Likelihood of This category reflects the likelihood of having significant future problems with the performance of 

future problems a component without aggressive maintenance levels well beyond what is considered “normal” for typical

navigation locks. It is important to note that “normal” maintenance is assumed to continue throughout

the study period.

1. Certainty of future problems without aggressive maintenance being undertaken to address problems.

2. Very good chance of future problems without aggressive maintenance. This rating indicates a

component that is expected to have problems, but not as soon or as problematic as those rated with

a value of 1.

3. Chance of future operational problems. Currently does not indicate any problems.

4. Unlikely that future problems will occur. Practically certain no significant problems will occur in the

future as long as normal maintenance continues in the future.

Relative cost to replace

(cost rating x quantity 

rating/5)

Unit Cost Cost Rating Quantity Quantity Rating

> $25 M 1 >20 1

$5M - $25M 2 11-20 2

$1M - $5M 3 5-10 3

$200K - $1M 4 2-4 4

<$200K 5 1 5

80 Great Lakes St. Lawrence Seaway Study
Maintaining the Infrastructure

THE CRITICALITY INDEX (CONTINUED)

Impact on navigation This category reflects the relative impact on navigation in the event that the component is not useable.

The repair may be necessary during the navigation season or it may be a component that can wait until

the winter shutdown season for repairs to be made. For some components, the repair can wait and the

locks may continue to be open, but the traffic may be impaired somewhat due to special procedures or

slowing filling/emptying times, etc.:

1. Navigation is shut down for a considerable length of time. The “failure” of the component requires

navigation to shut down for that facility until adequate repairs or other means can be used to

accomplish the same tasks.

2. Navigation is shut down for a significant amount of time, but not the level required for a rating of 1.

3. Navigation is shut down or special procedures/operations require traffic to transit through the facility

slowly for a length of time.

4. Navigation is shut down very briefly or special procedures/operations have a limited effect on

navigation traffic.

5. No significant impact on navigation.

Other impacts This category is used to rate the effect of component performance on non-navigation issues. This would

include structures like bridges, tunnels, and other components that if they failed to perform satisfactorily

would have an adverse impact on things like vehicular traffic, rail transport, hydropower generation,

flooding, environmental damages, etc. These structures may also have an adverse impact to navigation,

but that is reflected in the previous category.

1. Extensive adverse impact on non-navigation related issues. The “failure” of the component would

mean a potentially lengthy delay in order to restore the intended function or other similar use.

2. Significant impact on non-navigation related issues, but not to the level of those rated with a 1.

3. Impact on non-navigation related issues.

4. Little impact to non-navigation related issues.

5. No impact to non-navigation related issues.

Overall ranking The overall ranking will be the value that is ultimately used to determine the most critical infrastructure

for the purpose of this study. It is a relative value that combines the effects of the component’s

condition, operational redundancy, and potential impacts given unsatisfactory performance. It is relative

in terms of how it compares against other GLSLS components from all agencies (SLSMC, SLSDC, and

USACE). Components with the lowest values in this ranking system are considered the most critical

across the system’s for the purposes of this GLSLS Study. These components will be analyzed

individually through probabilistic means by completing a reliability analysis on them and integrating

them into the systems economic model. This will allow the overall GLSLS team to determine the

overall impacts associated with the performance of the most critical GLSLS infrastructure. The overall

ranking is a weighted sum of all the ratings for that component. The weighting applied to the various

ratings is as follows:

Rating Category Weighting factor

Redundancy 10%

Current condition 10%

Likelihood of future problems 30%

Relative cost to replace/upgrade 15%

Impact on navigation 25%

Other impacts 10%

Sum 100%

Great Lakes St. Lawrence Seaway Study 81
Chapter 5

SOO LOCKS

More than 80 million tons of commercial cargo passes through the Soo Locks every year. Virtually all cargo vessels use the MacArthur and Poe

locks. Only the Poe Lock has the necessary dimensions to pass all of the vessels that are presently in operation on the Great Lakes. If the Poe

Lock is out of service, a significant amount of commercial cargo is unable to transit the facility.

Mass concrete The lock walls are formed by 76 independent mass concrete gravity monoliths. The miter gate sills are

also mass concrete sitting on bedrock. There are no major issues for a structure of this age. Surface

deterioration around the seal area of the miter gate sills is addressed by routine maintenance.

Approach walls Movement because of erosion of underlying rock ledge. Accelerated by the use of ship bow thrusters to

maneuver. Heaviest damage is being repaired but wall will continue to deteriorate. The rock ledge is

eroding at rates of 0.025 -.05 m (1-2 in) per year. Voids beneath the concrete monoliths range from 

1 – 3 m (3-10 ft).

Gates Original gates are still in use and in good condition. Upper gate of Poe Lock has been bowed by impacts

from ships. It travels about 1 cm (1/2 inch) vertically during operation. Some steel gate components are

deformed and may cause structural problems. 

Secondary gates The MacArthur Lock has intermediate gates that can be used in an emergency, but they would limit

lock length. The Poe Lock has one set of upper miter gates. Its dewatering gates could be used as spare

upper gates, but then the chamber could not be dewatered. At the Poe Lock’s lower end a set of

intermediate gates could be used as backup for the lower miter gates.

Stoplogs There are no stoplogs for the

downstream end of the Poe Lock,

meaning that there is no redundancy

for (and little ability to service) the

downstream dewatering miter gates.

Valves The culvert valves, which also date

from the original construction, are

used to control the filling and

draining of the lock chamber. 

One valve failed a few years ago 

and had to be repaired.

Ship arrestors The ship arrestors at the Soo Locks

date to the original construction and

need to be upgraded. 

Machinery & controls All original equipment which is in

good condition but there are not

spare parts and the equipment is in

need of upgrading. The controls for

the Poe Lock miter gates are

inadequate. The entire system needs

to incorporate programmable logic

controllers. The MacArthur control

panel operates at 480 volts, which is

considered dangerous. 

Dam Head Race Crib Dike

 Poe Upper Approach Walls

Poe Upper Miter Gates

MacArthur Ship Arrester Machinery

Poe Lock Wall Monoliths

Poe Miter Gate Machinery

Dam Hydropower Plant – Structural

MacArthur Upper Approach Walls

Dam Head Race North Dike

MacArthur Electrical Controls

Poe Gate Sills

Lower Approach Walls

Poe Electrical Controls

MacArthur Dewatering Gates

Poe Ship Arrester Machinery

Poe Dewatering Gates

Ship Arresters

Poe Stiff Leg Derrick Crane – Structural

Poe Lower Miter Gates

MacArthur Still Leg Derrick Crane Machinery

MacArthur Culvert Valve Machinery

MacArthur Culvert Valves

Compressed Air System

Poe Culvert Valves

MacArthur Lock Wall Monoliths

MacArthur Ice Management System

Poe Stop Logs

MacArthur Miter Gates

Poe Culvert Valve Machinery

Dewatering System

MacArthur Miter Gate Machinery

MacArthur Stop Logs

Gate Sills

Power Supply to Project

Compensating Works Machinery

Compensating Works Gates

Dam Compensating Works – Structural

Steam Plant

Poe Still Leg Derrick Crane Machinery

Poe Ice Management System

0.0 1.0 2.0 3.0 4.0 5.0

At the Soo Locks, the most critical infrastructure relates to structural wall

components such as headrace dikes for the power canal and approach walls.

The Poe Lock’s upper miter gates and the MacArthur Lock’s electrical

controls also rank as critical components.

82 Great Lakes St. Lawrence Seaway Study
Maintaining the Infrastructure

WELLAND CANAL

The locks of the Welland Canal underwent an extensive rehabilitation program between 1985 and 1992 at a cost of $146 million. It involved:

removing and replacing backfill behind lock walls to reduce earth pressure; anchoring lock walls weakened by the earth pressure; and refacing the

lock walls that had deteriorated because of freeze-thaw action. All the necessary backfill replacement and anchoring has been completed as was

much of the refacing work. The rest of this work program, however, continues today.

Mass concrete Original concrete has suffered from freeze-thaw action, especially around the waterline. Refacing has been

done on the most degraded concrete but some work remains. About 90 percent of the locks’ surface has

already been re-faced.

Approach walls The timber pile tie-up walls, which were intended to be temporary when installed 45 years ago, have been

damaged by vessel impacts or unstable earth banks, and the timber piles are deteriorating. Piles and beams are

being repaired continuously. Shrinkage to timber decks led to loss of fill material, which has to be replaced

constantly. These structures will be replaced within ten years by a concrete deck and supporting steel piles.

Gates Because the steel miter gates, dating from 1932, have steel plating covering both sides of the girders, 

they are stiffer but harder to inspect and maintain. The gates are secured to the lock walls by a pair of

adjustable turnbuckles that are replaced regularly. The quoin and miter blocks are maintained to ensure

the gates fit with a good seal. Because the miter gates of the Welland Canal are riveted, they are more

resistant to fatigue.

Secondary gates Redundant intermediate gates at some

of the Welland Locks and three sets of

spare miter gates stored underwater

near Lock 1. A set of sector gates near

the upstream end at Lock 7 can be used

in an emergency but would have to be

placed under flowing conditions. There

are also dewatering gates upstream of

Lock 8 and downstream of Lock 1.

Stoplogs There are no stoplogs downstream of

the lower dewatering miter gates at

Lock 1, nor at Lock 8, meaning that

servicing of those dewatering miter

gates would require removal of the

gates by crane.

Ship arrestors The ship arrestors have all either

already been upgraded to direct

connect hydraulic connections or they

are in the process of being upgraded.

Machinery The machinery for operating the lock 

& controls gates and valves consists of mechanical

gears driven by electric motors. In

2005, a six-year program was initiated

to replace the original machinery with

hydraulic direct-connect machinery 

for both the lock gates and the valves.

The controls are being upgraded to

programmable logic controllers. 

0.0 1.0 2.0 3.0 4.0 5.0

Bridge No. 6 (Bascule) – Structural

Moveable Bridges – Structural (Bascule)

Moveable Bridges – Structural (Lift)

Entrance Walls – Timber Tie Up

Original Lock Walls – Single Locks

Original Gate Sills – Single Locks Single Sill

Bridge Abutments

Fixed Bridge 3A

Dikes and Banks

Sector Gates

Lock Miter Gates Single Locks – Single Gates

Lock Dewatering Gates – Timber

Sector Gate Machinery

Moveable Bridges – Electrical

Regulation Weir Concrete

Original Lock Walls – Twin Locks

Culvert Valves

Fixed Bridges – Structural

Entrance Walls – Concrete

Ship Arresters

Regulation Weir Machinery (All Weirs)

Regulation Weir Gates/Valves

Lock Dewatering Gates – Steel

Tunnel – Town Line

Still Leg Derrick Crane Machinery

Still Leg Derrick Cranes – Structural

Piers and Break Waters

Lock Miter Gates Double Locks – Single Gates

Compressed Air System

Original Gate Sills – Single Locks Double Sills

Original Gate Sills – Twin Locks Single Sill

Original Gate Sills – Twin Locks Double Sills

Lock Miter Gates Single Locks – Double Gates

Lock Miter Gates Double Locks – Double Gates

Moveable Bridges – Machinery

Power Supply

Electrical Controls at Locks

Original MG Machinery

New Direct Connect MG Machinery

Resurfaced Lock Walls

Dewatering System

Resurfaced Gate Sills

Ship Arrester Machinery

Stop Logs

Culvert Valve Machinery

New Direct Connect CV Machinery

At the Welland Canal, the most critical infrastructure components are those

associated with moving lift bridges and approach walls. Many of the problems

associated with concrete lock walls and machinery are presently being

addressed under ongoing rehabilitation work.

Great Lakes St. Lawrence Seaway Study 83
Chapter 5

MLO SECTION – U.S. COMPONENTS

The U.S. portion of the St. Lawrence Seaway consists of the Snell and Eisenhower Locks, which are virtually identical in design but which

manifest significant differences in their condition. The Eisenhower Lock suffers from poor concrete quality, which has led to advanced concrete

degradation of the lock walls and seepage around a road tunnel that provides access to the Moses-Saunders hydroelectric dam.

Mass concrete While concrete at the Snell Lock is in relatively good shape, the concrete at the Eisenhower Lock has

deteriorated significantly. Up to 1.2 m (4 ft) of concrete has to be removed to get to sound underlying

concrete. The service tunnel through the lock sill has experienced cracking, leakage, and ice build-up in

winter. Grouting has been used repeatedly but the problem continues to worsen.

Approach walls The approach walls and guide walls at both the Snell and Eisenhower Locks have suffered considerable

wear and tear from ship impacts. They maintain their integrity, though regular maintenance is required.

Gates The upper miter gates are in good operating condition at both locks. The pintles, quoin blocks and

miter blocks are subject to significant wear and are replaced on a ‘fix-as-fails’ basis. The lower gates at

both Snell and Eisenhower show considerable cracking. Cracking in the Snell gates is about three times

as extensive as in the Eisenhower gates and is a major cause for concern.

Stoplogs The Snell and Eisenhower locks have complete sets of stoplogs for dewatering. They are installed using

stiff-leg derrick cranes. The Eisenhower Lock also has an emergency vertical lift gate that protects the

upstream pool level in the event of a catastrophic failure of the miter gates.

Ship arrestors The ship arrestors at the Eisenhower and Snell Locks date from the original construction and are in

need of modernization.

Machinery & controls Programmable logic controllers are

used to control both the Snell and

Eisenhower Locks. The latter houses

the control room for SLSDC’s new

vessel tracking system, which

monitors ship movements throughout

the Seaway. The SLSDC will need

new ship positioning, hydraulics 

and ship mooring technology to

harmonize lock operations with 

the SLSMC.

0.0 1.0 2.0 3.0 4.0 5.0

Lock Wall Monoliths/Mass Concrete (Eisenhower)

Lower Miter Gates – Single Gates

International Seaway Bridge – South Span

Lock Wall Monoliths/Mass Concrete (Snell)

Tunnel Structure at Eisenhower Lock

Upper Miter Gates – Single Gates

Guide Wall Extension

Culvert Valves

Miter Gate Sills – Single Sill

Ship Arrester Machinery

Compressed Air System

Miter Gate Machinery

Flow Control Dike

Upper Guide Wall

Lower Guide Wall (Eisenhower)

Guard Walls

Electrical Controls

Ship Arresters

Stiff Leg Derrick Cranes – Structural

Outlet Diffuser Structure

Emergency Vertical Lift Gate

Culvert Valve Machinery

Lower Guide Wall (Snell)

Power Supply

Dewatering System

Chapman Valve

Ice Flushing System (Eisenhower)

Stop Logs

Still Leg Derrick Machinery

Vertical Lift Gate Machinery (Eisenhower)

84 Great Lakes St. Lawrence Seaway Study

At the SLSDC facilities on the St. Lawrence River, the most critical areas

are associated with concrete quality at the Eisenhower Lock, the condition

of the lower miter gates at both locks, the south span of the Seaway

International Bridge, and the Eisenhower Lock highway tunnel.
Maintaining the Infrastructure

MLO SECTION – CANADIAN COMPONENTS

The Canadian portion of the St. Lawrence Seaway is managed by the St. Lawrence Seaway Management Corporation (SLSMC), operating

under a long-term contract from Transport Canada.

Mass concrete Four of the locks suffer from long-term concrete degradation caused by Alkaline-Aggregate Reaction (AAR).

This causes a steady narrowing of their width as well as alignment problems with the lock gates. The most

severely affected are the quoin blocks where the lock gate hinges are attached to the wall. Some repairs to the

quoin blocks have already been undertaken, but more are needed. The lock walls at the St. Lambert and

Beauharnois locks are the most severely affected by AAR.

Gates Seven sets of miter gates have been realigned because of AAR. An entire winter maintenance season is required

to reset miter gates, which involves reworking the concrete recesses and resetting contact blocks. It costs more

than $1 million to realign each miter gate. There are double gates at the downstream end of St. Lambert, the

upstream end of Cote Ste. Catherine, the downstream and upstream ends of the Lower Beauharnois Lock and at

the upstream end of the Upper Beauharnois Lock.

Secondary gates The other operational lock gates all have spare gates hanging in recesses on the lock wall but without any

operating machinery connected. The exception is the lower gates of the Upper Beauharnois Lock, which has

only single gates and no spare gates.

Stoplogs All of the SLSMC locks at Maisonneuve are equipped with stoplogs at both the upstream and downstream end.

The only exception is at Beauharnois, where the upper and lower locks are treated as a single unit with stoplogs

at the upper end of the upper lock and at the lower end of the lower lock. All stoplogs are installed and

removed using a stiff-leg derrick crane.

Ship arrestors The SLSMC arrestors use a similar boom and wire arrangement as used elsewhere throughout the system. 

The system is regularly maintained and operational. An upgrade to hydraulic connections similar to those at

Welland has not yet been undertaken.

Machinery All of the locks, bridges and weirs managed 

& controls by Canada’s SLSMC have implemented

programmable logic controllers (PLCs).

There is an initiative currently under way to

upgrade the PLCs to a more modern design.

Operator interfaces are computerized and 

the application software is being upgraded.

The system is also changing to a remote

control system. Control wiring and panels

are due for replacement because of corrosion

caused by high levels of humidity in the

galleries.

0.0 1.0 2.0 3.0 4.0 5.0

Mass Concrete/Lock Wall Monoliths (Lower Locks)

Lift Bridges – Structural (Bridge 2, 3, 7a & 7b, 9 & 10)

Lift Bridges – Machinery (Bridge 2, 3, 7a & 7b, 9 & 10)

Bascule Bridges (2) – Structural

Swing Bridge

Stiff Leg Derrick Crane – Structural

MG Sills & Breastwalls (Single Gate)

Stiff Leg Derrick Crane – Machinery

Sector Gates (Cote Ste Catharines, Upper Beauhornois

Dikes and Banks

Lock Miter Gates – Single Gates

Bascule Bridges (2) – Machinery (Cote & Iroquois)

Mass Concrete/Lock Wall Monoliths (Iroquois)

Approach Walls (Gravity Walls)

Swing Bridge Machinery

Fixed Bridges (10) – Structural

Regulation Weir Concrete

Approach Walls (Lower Beauhornois)

Sector Gate Machinery

Miter Gate Machinery (Single Gated)

Approach Walls (Upper Beauhornois)

Culvert Valves

Ship Arrester Machinery

Submerged Ship Arrester Machinery (St. Lambert)

Ship Arresters

MG Sills & Breastwalls (Double Gate)

Dewatering Pumps

Lock Miter Gates – Double Gates

Culvert Valve Machinery

Compressed Air System

Stop Logs

Miter Gate Machinery (Double Gated)

Ice Flushing Valves (St. Lambert)

Weir Gate Machinery

Weir Gates

Sector Gate Machinery (Iroquois)

Sector Gates (Iroquois)

Ice Flushing Valve Machinery

Moveable Bridges (9) – Electrical

Power Supply

Electrical Controls at Lock

Ice Flushing Valves (Cote St. Catharines)

The Canadian locks near Montreal are suffering from long-term concrete

degradation caused by Alkaline-Aggregate Reaction (AAR). This results

in gradual expansion, deterioration, cracking, porosity and loss of integrity

of the concrete. AAR is resulting in as much as a 2.5 centimetres (1 inch)

narrowing of locks every five years. If lock width shrinks below 79 feet 

6 inches then larger vessels will not be able to pass in December or March

or special operational procedures will have to be implemented. Forecasts

based on the engineering analysis suggest that at the current rate of

concrete swelling, the St. Lambert lock will meet this critical width before

2015. AAR is also causing ongoing alignment problems with the lock

gates and valves. The most severe of these involves the quoin blocks

where the lock gate hinges are attached to the wall. Some repairs to the

quoin blocks have already been undertaken, but more are needed.

Great Lakes St. Lawrence Seaway Study 85
The four charts presented in the insets show the criticality

rankings of each of the lock components examined

within each navigation corridor. A brief examination 

of these charts shows that each site has several high

priority components (rankings lower than 2), the

majority of the components rate around 3 (indicating

some reliability issues and concerns over repair and/or

maintenance) and a few rate over 4 (indicating

components that are in new or good condition and/or

have relatively low failure consequence impacts).

Generally one can observe that the patterns of the

criticality curves are the same from lock-to-lock

indicating a general similarity in the overall state of

repair of the various components.

Despite differences in construction and maintenance

strategies, one important result of the criticality

assessment was the finding that the rankings for locks

across all four parts of the GLSLS are remarkably

similar. The overall mean for the four sets of facilities

are remarkably similar (table 5.1), ranging closely

around 3.4. The worst rank (1.4) is associated with the

concrete at four Maisonneuve lock sites that are affected

by Alkaline-Aggregate Reaction (AAR), followed

closely by the concrete problems at the Eisenhower

Lock, the timber tie-up walls at Welland and the upper

approach walls at the Soo Locks. The most critical gates

are the upper miter gates on the Poe Lock and the lower

miter gates at the Snell and Eisenhower locks.

OPERATIONS AND

MAINTENANCE

The locks on the GLSLS have an excellent history of

service to the navigation industry. The Seaway locks

operate a little more than nine months a year, typically

closed between late December and late March because of

winter conditions. The extent and duration of ice cover

is a factor in determining the length of the shipping

season. Over the period 1996 to 2005, the average

Seaway navigation season lasted 276 days. The upper

lakes season lasts some ten and a half months. The Soo

Locks generally close between January 15 and March 25

in accordance with mandated operating seasons.

The winter shutdown period is a key element in the

operational sustainability of the system. Far from being

dormant time, the winter shutdown is used for detailed

inspections, repairs and ongoing maintenance. The

ability to dewater and inspect the structures on a fairly

routine basis during the winter shutdown means that

problems can often be identified before they reach a

critical stage. Once a problem is recognized, it can be

scheduled for repair. 

Each region has an Asset Renewal Plan or Recapitalization

Plan to make planned investments to maintain or

upgrade the system.

On the Canadian side of the system, the SLSMC has a

five-year Asset Renewal Plan that involves risk-based

inspections and funding. This is a key component of the

SLSMC’s commercialization agreement with Transport

Canada. The current asset renewal plan, which covers

the five-year period between 2003/04 to 2007/08,

allocates a spending envelope of $170 million for major

maintenance and capital expenditures on the Canadian

portion of the Montreal-Lake Ontario section of the

Seaway and the Welland Canal. The Asset Renewal

Plan is managed by the SLSMC and overseen by the

Capital Committee, which is composed of two members

from Transport Canada and two members from the

SLSMC. The Committee approves, within a

predetermined envelope, asset renewal projects on an

annual basis and meets regularly to review and approve

changes to the plan, if needed, to ensure the reliability

of the system.

On the U.S. side of system, the SLSDC and USACE

both depend on congressional appropriations to provide

funding for infrastructure renewal. This process often

makes it difficult to plan for long term investment in

maintenance. On the other hand, it should be noted

that none of the U.S. infrastructure is as old as that in

the Welland Canal nor does the U.S. side have the

problems with concrete that are found at the MontrealLake Ontario section of the Canadian Seaway. As the

systems continue to age, the USACE and SLSDC

components are coming due for rehabilitation on a scale

similar to those already undertaken or under way on the

Canadian side.

Chapter 5

TABLE 5.1

Summary of criticality assessments

Summary of criticality indices Overall Soo-USACE Welland-SLSMC MLO-SLSDC MLO-SLSMC

Mean 3.40 3.42 3.51 3.20 3.35

Min 1.40 1.90 1.60 1.70 1.40

Max 4.80 4.80 4.80 4.80 4.80

86 Great Lakes St. Lawrence Seaway Study
Forecasting maintenance

requirements

It is expected that cyclical and emergency maintenance

costs will continue rising at an ever increasing rate

because of age and wear on its infrastructure. The safety,

reliability and efficiency of the GLSLS continue to be

paramount considerations for planners. In this regard,

past operations and maintenance have proven to be

highly successful: the system is available more than 

98 percent of the time with a superior record of

operational safety. Even so, the costs associated with

operations and maintenance are rising and problems

with the age or condition of the infrastructure have

resulted in vessel delays: in 1985 a lock wall failure

interrupted traffic through the Welland Canal and in

2004 a miter gate at the Poe Lock disrupted passage

through the Soo Locks. Even more critical is the fact

that the majority of the lock sites throughout the system

possess only one lock chamber instead of parallel or

auxiliary chambers. This means that there are numerous

single points of failure throughout the system that can

shut down entire navigation corridors if individual

components break down.

If the system is to retain its competitive advantage,

resources must be deployed in a way that optimizes

overall system integrity and safety. Three areas in

particular require attention. The first is routine main ten -

ance of basic lock operations. The second is maintenance

of the physical structures of the system, including bridges

and tunnels, together with their ancillary machinery.

The third category involves dredging of channels to

maintain the waterways at authorized depths. Maintenance

also incurs costs associated with the personnel and

overhead associated with day-to-day operations. It also

includes buildings and grounds, the floating plant

required for ongoing maintenance activities as well as

various material costs. 

Physical infrastructure

maintenance

In terms of the physical infrastructure, the following are

the key areas that require ongoing attention:

• ensuring the structural integrity of the lock gates,

• addressing wear on lock gate mechanisms,

• preserving the structural integrity of the lock

chambers and their approaches,

• keeping flow control mechanisms functional, and 

• maintenance of the bridges and tunnels that cross 

the system.

The infrastructure inspections and criticality analyses

developed by the Engineering Working Group provide a

prioritized list of infrastructure components that are at

high risk because they are likely to fail, have high repair

costs or have a significant impact on navigation.

Building on this, a reliability analysis was completed to

predict the likely long-term performance of these major

lock components. A combination of computer models,

analytical methods and expert elicitation was used to

determine which elements were priorities for mainten -

ance or upgrade. This analysis also predicted the

consequences of unsatisfactory performance in terms of

both navigation delays and repair costs as structures age. 

The reliability of infrastructure components through

2050 was assessed in two different ways. Where the

nature of the component and its failure mechanism is

readily amenable to a technical analysis, detailed

engineering analysis was undertaken. In other cases,

where the failure process consists of a less clearly-defined

cause-and-effect relationship, the experience and

judgment of the engineering team combined with local

engineering staff was drawn upon through a formal

evaluation process known as ‘expert elicitation’. 

While these two processes are quite different, their

outputs are similar. They consist of: a probabilistic

analysis of the likelihood of failure over time (reliability

analysis); event trees to identify the expected sequence

of events given various levels of failure (minor, major 

or catastrophic); descriptions of the nature of repair

required depending upon the failure mode of the

component; and cost estimates for each of the event

scenarios identified. 

There are two types of reliability modeling: timedependent and non-time-dependent. Time-dependent

reliability analysis is used for system components that

degrade as the number of usage cycles and/or age

increase. For these cases, reliability changes over time.

This analysis is used for gates, machinery, valves, mass

concrete degradation, mechanical and electrical

components, anchors and walls subject to fatigue and

wear. In these cases, the component’s probability of

failure or unsatisfactory performance increases over time.

For components where the risk of failure is constant

over time, such as the seat abutments at Welland Bridge

#4, non time-dependent reliability analysis is used.

This process of reliability analysis modeling consists of a

combination of engineering and probabilistic analyses

that reflect the approaches to infrastructure maintenance

commonly adopted by maintenance engineers at both

the Canadian and U.S. facilities. In order to provide a

uniform reliability analysis across the entire GLSLS

system, a unified reliability analysis procedure has been

Maintaining the Infrastructure

Great Lakes St. Lawrence Seaway Study 87
employed. The USACE has applied a systematic

approach to reliability analysis to other lock systems

throughout the U.S. and has adapted it for use in 

the GLSLS.

The reliability modeling results in probabilities of

unsatisfactory performance for non time-dependent

components and hazard rates for time-dependent

components. These values are identified for the period

2010 through 2050. For non time-dependent components,

the values are the same in each year. For time-dependent

components, each year could have a different value. 

The reliability modeling also provides consequence

event trees for each component, depicting several repair

options given the limit state of the component. Such

analysis includes the cost of physical repair, the time

that the chamber will have to be closed for each repair

option, and the effect that repair will have on future

reliability. Event trees vary for each component but the

following pattern generally applies:

• The first branch of the event tree is the annual

probability of unsatisfactory performance (PUP) for

the component for any particular year between 2010

and 2050. Since the PUP typically increases through

time as the component ages and becomes less reliable,

this first branch of the event tree is typically

represented as a hazard function curve.

• The second branch is the level of repair associated

with the annual PUP. In general, this branch will

have two or three legs whose

total percentage must equal

100 percent. The percentages

were selected by the team of

engineers that developed 

the model, in consultation

with operations personnel

experienced with the repair

techniques for the particular

component. 

• For each branch, there is an

estimate of the cost to repair

the component for each level

of repair, along with the

amount of time in days the

chamber is closed to navi -

gation. These cost and closure

estimates were also developed

by the engineering team that

produced the model, in

consultation with appropriate

operational personnel.

• For each branch, the upgrade to future reliability

based upon the repair is identified. This effect is

based upon the engineering judgment of the team

that developed the model. 

Several key system components have been identified 

for detailed reliability analysis. This work has involved

the development of predictive relationships for the

progression of wear and the initiation of damage for

each identified component. In some instances, this

analysis has been based on detailed computer modeling

and engineering stress analysis. In other cases, it has

relied on the expert evaluation of the engineering staff

responsible for operation and maintenance of the

facilities.

As an example, Figures 5.2 and 5.3 show the results of

the reliability modeling undertaken on the structural

members of the Seaway International Bridge which

crosses the Montreal-Lake Ontario section of the system. 

The first figure shows the likelihood of failure over time

(reliability analysis) in blue superimposed on the event

tree (which identifies the expected sequence of events

given either a minor or major failure) under a scenario

where the investments necessary to ensure continued

reliable performance the bridge members are made. 

This maintenance approach is generally referred to as

‘proactive’. In this case, maintenance and rehabilitation

works are initiated earlier in order to reduce the risk of

long, unscheduled shutdowns. This strategy is undertaken

Chapter 5

FIGURE 5.2

Likelihood of failure if investments are made in maintenance

FIGURE 5.3

Likelihood of failure if no investment is made in maintenance

88 Great Lakes St. Lawrence Seaway Study
on the basis of forecasts of risk and reliability in the

system. It uses a variety of analytical tools to develop

reasonably accurate estimates of when components are

likely to fail and deals with them before they occur.

Since timing is of the essence in pursuing a proactive

strategy, reliability analysis is used to evaluate the proba -

bilities of failure and thus optimize system reliability.

The second figure shows the same relationship (with the

reliability analysis now shown in red) reflecting the

situation where the bridge members continue to degrade

without any significant maintenance reinvestments.

Such components are either repaired or replaced when

they are observed to have reached the end of their service

life. This approach is often referred to as a ‘reactive’

approach: repairs are initiated when parts reaching a

certain level of allowable wear or deformation. It is

important to note that ‘reactive’ does not neces sarily

mean that components are not replaced until they fail.

Components are monitored as wear, fatigue, degradation,

and aging progress. Engineering analysis sets ‘hazard

limit states’ which define the maximum allowable wear

or degradation at which point safety or reliability risks

become unacceptable. When a component reaches this

hazard limit, maintenance or repair works are initiated.

This approach to maintenance has the benefit of getting

the maximum use out of every component. It also delays

maintenance expenditures for as long as possible. On the

other hand, by delaying maintenance, the strategy also

runs the risk that at least some components may fail

unexpectedly, before they can be replaced. If they do,

the system incurs lengthy, unscheduled maintenance.

As can be seen when comparing the ‘proactive’ and

‘reactive’ approaches, increased structural maintenance

under a proactive strategy will result in the hazard

function dropping back down upon completion of the

maintenance, thereby reducing the probability of failure

through the period of analysis. Rehabilitation or

replacement of components before problems and failures

begin to occur is often cost effective because unplanned/

unscheduled reactive repairs are often more costly, less

effective, and more disruptive to navigation. 

Navigation channel maintenance

Maintaining navigation through the GLSLS depends, in

part, on ensuring that all channels in the system have a

minimum navigable depth. In addition to dredging,

there is also a need to maintain aids to navigation such

as buoys, channel markers and range markers.

Great Lakes St. Lawrence Seaway Study 89

Surveys are regularly undertaken to map channel

bathymetry. Areas of shoaling are identified and marked

for maintenance dredging. Though the GLSLS has an

overall length of 3,700 km (2,300 miles), maintenance

dredging is only needed in limited sections of the 

system – proportionally far less than is required for other

North American navigational systems. Unlike inland

waterways such as the Mississippi system, the waters of

the Great Lakes do not carry a lot of sediment because

of their depth and because water flows are low relative

to the size of the lakes. In effect, the Great Lakes act as

decanters: the average residency time for water in the

Great Lakes ranges from as much as 190 years for Lake

Superior to as little as two years for Lake Erie. Sediments

carried into the Great Lakes have a long time to settle

before those waters exit through the rivers that form the

navigable waterways of the system. Thus sedimentation

is minimal in the majority of the navigation channels

and generally consists of recirculation of local sediments. 

On average, maintaining channel depth costs the

equivalent of $20 million per year for both the dredging

itself and the management of the dredged material.

Funding for this work is contingent upon congressional

approval. To put these statistics in perspective, an

average of about 185 million tons annually is shipped

through the GLSLS upstream of Montreal. Dredging

three million cubic metres per year represents roughly

one ton of dredged material for every 40 tons of goods

passing through the system. 

Of the two to four cubic metres of annual maintenance

dredging, some 10 percent consists of contaminated

sediments – a legacy from past decades when industrial

pollution controls were less stringent. These sediments

are routinely re-worked through the action of waves and

currents, settling out of suspension in the deeper,

quiescent waters of the navigation channels and berths.

Consequently, the sediments that are dredged in order to

maintain a navigation channel can be contaminated,

and thus require containment within dikes to prevent

them from spreading through the environment. 

Maintaining the Infrastructure

A 2005 survey of U.S. flagged Great Lakes carriers reported

that the most important issue facing Great Lakes operators

was the critical need for dredging [U.S. Department of

Transportation, Maritime Administration 2005]. The U.S.

Lake Carriers Association [2005] reports that the backlog of

required USACE maintenance dredging at Great Lakes ports

has resulted in a reduction in drafts ranging from 0.46 m 

(18 in) at Duluth and in the St. Marys River to as much as

1.37 m (54 in) at Cleveland and Fairport on Lake Erie. Ship

draft directly affects the cargo capacity of bulk carriers. A 1.37 m

(54 inch) reduction in draft on a 1,000 ft ore carrier results

in a loss of 13,000 tonnes (14,400 tons) of carrying capacity. 
There are also many locations throughout the GLSLS

system where environmental dredging is being undertaken

as opposed to maintenance dredging. Environmental

dredging is undertaken for the sole purpose of removing

harmful contaminants from the environment, indepen -

dent of navigational concerns. In many cases, sediments

gathered during maintenance dredging activities are

clean and can be reintroduced into the water column in

areas adjacent to the dredging site. From an environmental

perspective, this is the most desirable alternative since

regional-scale sediment management (under programs

such as the USACE Regional Sediment Management

program) is the most prudent means of responding to

interruptions in the natural flow of sediments caused by

development and coastal structures such as harbors and

navigation systems. 

USACE records indicate that some 32 percent of

sediments from maintenance dredging are clean enough

to allow for open-water disposal, and 12 percent of the

sediments dredged are re-introduced into the coastal

zone as beach nourishment (average of 1993-96 statistics).

Where containment is required, the development of

approved sediment containment sites is both lengthy

and costly. As a result, dredging costs in the Great Lakes

average about $8 per cubic yard, considerably higher

than the average of $3 per cubic yard across North

America. The capacity of contaminated sediment disposal

sites is an ongoing concern for port operators throughout

the system. Dredging costs in the St. Lawrence River

typically run significantly higher due to a lack of

dredging contractors and the higher mobilization costs

associated with use of contractors from the Great Lakes.

In addition, contained upland spoiling of dredged

materials is typically required in this area, and if

contaminated the dredged material has to be transported

to a special landfill.

OPTIMIZING MAINTENANCE

The infrastructure of the GLSLS must be maintained to

keep it operational. It is possible to plan for and

schedule maintenance so as to minimize disruptions to

shipping: for example, most of the work on lock

chambers is performed over the winter shutdown when

there is no shipping. However, not all maintenance can

be planned in this way. Criticality assessments coupled

with reliability data have identified key operating

components with an elevated risk of failure. If such

components fail unexpectedly, unscheduled repairs must

be performed that incur additional costs and disrupt

shipping. The timing and duration of any system closure

imposes costs on the transportation industry through

delays or diversions that can be many times larger than

the cost of the repair itself.

90 Great Lakes St. Lawrence Seaway Study

Informing future maintenance

strategies

Determining an optimal strategy for maintaining the

GLSLS infrastructure demands consideration of diverse

factors over a long time horizon. It requires an under -

standing of the economics and competitiveness of

waterborne trade, the existing and future conditions of

system infrastructure and fleets, and the behavior or

decision making of shippers when faced with system

closures. To form a sound and reasoned basis for

understanding these and other issues, the GLSLS Study

undertook numerous detailed economic and engineering

studies and developed a suite of sophisticated analytical

tools to support the infrastructure maintenance

optimization:

• Vessel Movement Database provides detailed vesselspecific and movement-specific information for

historical periods so that the “existing conditions” 

of system usage are understood;

• Cargo Forecasts describes expected movements of

cargo through the system (by lock corridor) so that

“future conditions” of system usage are understood;

• Existing Infrastructure Conditions provides a

detailed component level assessment of the current

state of each lock component;

• Component Risk Model simulates the engineering

condition reliability information over time and

tabulates the system service disruptions for the

calculation of expected repair costs over time;

• Vessel Trip Cost Simulator forecasts the effect of

lock failures on marine transportation within the

GLSLS system. The simulation calculates vessel

transit times and associated operating costs with and

without lock or system failures over the forecast

horizon. The simulation also documents individual

vessel movements lost from the shipping season

because a structural failure did not allow all of a

season’s vessel movements to be completed.

• Shipper Survey / Transportation Rate estimates the

expected shipper response to discrete closure events

and the shipping cost differences between waterborne

cargo movements relative to the least cost overland

routing for the variety of cargo movements through

the system. 

Chapter 5
While each of these tools and data sources can be viewed

in isolation, they are linked together to facilitate the

quantification of the net economic benefits associated

with different maintenance strategies. The various

databases, forecasts and lock risk and vessel simulation

modeling tools feed data into an economic evaluation

model that aggregates all of these distinct but interrelated inputs. The evaluation model processes the data

from all of the above components over a fifty year time

horizon to determine if the additional costs associated

with a more intensive maintenance regime are

economically justified. 

Cost estimates

The figures that follow show the projected operation

and maintenance costs (all costs are in 2007 nominal

dollars) for the physical infrastructure necessary to

ensure the system continues to provide the same degree

of reliability as in the past. These costs include

navigation channel maintenance for the Seaway portion

of the system, but do not include navigation channel

maintenance for the balance of the connecting channels

(St. Clair River, Lake St. Clair, Detroit River) or

federally maintained port areas.

These projections apply the results of the reliability

analyses to project the timing of major infrastructure

investments required to minimize the potential for

system interruptions due to component failures and

associated repair downtime. Each figure offers a profile of

expected costs, year by year, given the current condition,

reliability analysis and criticality indices prepared by the

Working Group. It should be noted that the graphs

consistently show an initial spike early in the projected

operation and maintenance requirements for each

corridor that reflects the fact that past funding limi -

tations have resulted in the delay in various operation

and maintenance activities. These delayed activities

need to be addressed on a priority basis in order to

ensure continued system reliability, and as such are

typically timed to occur early in the period of analysis. 

As shown in Figure 5.4, the SLSMC – Montreal-Lake

Ontario (MLO) region has the highest structural

maintenance costs in the system although it contains

the second highest amount of infrastructure: five lock

chambers, six lift bridges, two bascule bridges and one

swing bridge (the most infrastructure is located in the

SLSMC – Welland Canal section). Base operation costs

in the SLSMC-MLO region averages $31 million

annually. 

Of the structural maintenance costs, the largest single

maintenance component is the Alkaline-Aggregate

Reaction (AAR) issue which exists at four of the five

lock chambers in the region. From 2013 through 2029,

approximately $20 million is assumed annually for

vertical face resurfacing at the four sites ($80 million

total for each site). Repair dates for the AAR resurfacing

at Lower Beauhornois and Cote St. Catherine have been

accelerated ahead of the optimal time (beyond 2040)

predicted in the reliability model hazard rates. The hazard

rate limit state was defined by the growth of the concrete

that would reduce lock width and restrict ship passage.

There is also a secondary problem that exists with

spalling and degradation of the wall surfaces due to

freeze/thaw cycles, ship impact and AAR cracking. The

Engineering Working Group considers this secondary

problem significant enough to expedite the wall

resurfacing for these projects. Despite this rehabilitation

there is an additional $1 million required annually, on

average, to address other AAR issues at the structures. 

In addition, the remaining seven stiff leg derrick cranes

(one assumed replaced in 2009) are replaced from 2010

through 2013 at a cost of $1 million each. Six lift

bridges are assumed to be rehabilitated at a cost of 

$0.5 million each from 2010 through 2015 (and again

from 2035 through 2040). The remainder of the

structural maintenance costs are primarily for gates,

valves, ship arrestors, ice management, concrete repair

and electrical/mechanical repairs and upgrades.

Maintaining the Infrastructure

FIGURE 5.4

SLSMC – Montreal-Lake Ontario (MLO)

Millions

$70.0

$60.0

$50.0

$40.0

$30.0

$20.0

$10.0

$0.0

20102020203020402050

Structural Maintenance Costs

Base Operations Costs

Great Lakes St. Lawrence Seaway Study 91
As shown in Figure 5.5, the SLSMC – Welland Canal

region has the second highest structural maintenance

costs in the system and contains the most infrastructure

(11 lock chambers, three lift bridges and eight bascule

bridges) of any of the regions. Base operation costs for

the region are expected to average between $38 to 

$41 million annually. 

Of the structural maintenance costs, a total of 

$82.5 million is needed for replacement of five of the 

six timber tie-up walls from 2010 through 2019 

($8.25 million per year). The ramp up in structural

maintenance costs from 2025 through 2044 is for

refacing of the lock walls at all 11 lock chambers at a

cost of approximately $16 million per year. The lift

bridges are estimated to require approximately $0.5 million

annually for maintenance and a total of $3.8 million in

rehabilitation ($1.9 million in years 2010 and 2035).

The bascule bridges are estimated to require approxi -

mately $1.4 million annually for maintenance and a total

of $19.3 million in rehabilitations and replacements

($2.65 million for fixed Bridge 3a rehabilitation, 

$3.18 million for Bridge 4 abutment rehabilitation, 

$8.5 million for Bridge 6 tread plate replacement 

and $5 million for Bridge 19 rehabilitation). 

Figure 5.6 presents the SLSDC – MLO region, which

contains two lock chambers, one bridge and one tunnel.

Base operation costs average around $17 million

annually. It should be noted that the base operations

costs for this region reflects, among other requirements,

the fact that certain base requirements were delayed in

the past due to funding limitations and the requirement

to address other higher priority maintenance needs

within the available annual funding. As such, the initial

base operations level of funding reflects the need to

accomplish these activities early in the analysis period.

The base operation cost spike in 2015 occurs from a

$18.2 million floating plant investment and $5 million

in channel maintenance costs while the spike in year

2017 occurs from a $10.2 million floating plant

investment and an additional $5 million in channel

maintenance costs. Additional $5 million spikes for

channel maintenance occur in years 2010, 2023, 2031,

2039 and 2047. 

Of the structural maintenance costs, general mainten -

ance accounts for roughly $7 million annually and lock

wall mass concrete maintenance amount to approxi -

mately $1.5 million annually. The spike in 2010 through

2012 structural maintenance costs occur from a 

$10.6 million investment in the Seaway International

Bridge for sandblasting and painting. In addition, there

is a $13.6 million investment in 2020 and 2021 for

bridge deck replacement.

Chapter 5

FIGURE 5.5

SLSMC – Welland Canal

Millions

$80.0

$70.0

$60.0

$50.0

$40.0

$30.0

$20.0

$10.0

$0.0

20102020203020402050

Structural Maintenance Costs

Base Operations Costs

FIGURE 5.6

SLSDC – Montreal-Lake Ontario (MLO)

Millions

$70.0

$60.0

$50.0

$40.0

$30.0

$20.0

$10.0

$0.0

20102020203020402050

Structural Maintenance Costs

Base Operations Costs

FIGURE 5.7

Soo Locks

Millions

$70.0

$60.0

$50.0

$40.0

$30.0

$20.0

$10.0

$0.0

20102020203020402050

Structural Maintenance Costs

Base Operations Costs

92 Great Lakes St. Lawrence Seaway Study
Figure 5.7 presents the Soo Locks, which consists of two

operating lock chambers and a hydropower plant which

supplies power for lock operations. Base operation costs

average around $12.6 million annually. 

Of the structural maintenance costs, an average of 

$7 million annually is needed for general maintenance.

The initial surge in costs in 2010 come from the west

center pier wall extension ($3.1 million), miter gate

machinery rehabilitation at both lock chambers 

($5.85 million) and crib dike rehabilitation at the north

hydropower plant. The spike in costs in 2012 are from

Poe Lock upper miter gate rehabilitation ($3.5 million)

and work on the upper approach walls at both chambers.

As noted previously, these are the projected costs

necessary to continue to maintain system reliability. 

If the priority components (as determined through the

engineering criticality index method) are not main -

tained as recommended, risk of unscheduled repair costs

and transportation disruptions increase. Through simu -

lation modeling of the priority component engineering

reliability data (hazard functions and event trees)

expected unscheduled repair costs can be estimated.

This comparison of costs with and without proactive

maintenance of the priority components to maintain

these components in a reliable condition reveals that

the costs to the governments are not significantly

different in total, although the timing of the expen -

ditures are. The real benefit, however, for maintaining

them in a reliable condition lies in the potential traffic

disruptions that would occur if they were not maintained.

Service disruptions in the system temporally stop or slow

down vessel transits through the system. Through the

same simulation modeling of the priority component

engineering reliability data, expected transportation

impacts / costs can be estimated. Impacts include increased

vessel delay costs and potentially unmet tonnage flows. 

The consequences of service disruption vary by shipment

and will be dependent upon the service disruption type

(closure or service time increase), location of the disrup -

tion (at a single or dual lock chamber site), duration and

timing (beginning, middle or end of the navigation

season). Impacts from a service disruption can include

not only shipment delay, but also return trips to unload

a shipment for re-routing on an alternative transpor -

tation mode, vessel idling, stockpile depletion and 

plant shutdowns. 

With the system consisting of essentially a series of

structures that must be transited with no alternatives

(except at the Welland Canal flight locks and the dual

chambers at the Soo Locks complex) the probability of

completing a trip is the probability of each of the poten -

tial obstruc tion points (locks and bridges) operating. 

A closure of one of the structures in the series essentially

closes the system. Closures, or a sequence of closures,

during the navigation season can result

in incomplete vessel trips since there is a

limited number of vessels that shuttle the

cargo from origin to destination. 

Figure 5.8 includes the projected main -

tenance costs required to proactively

address those infrastructure components

for which detailed engineering reliability

analyses were undertaken. These costs

are then compared to the projected

impacts of system disruptions if these high

priority components are not addressed in

a proactive manner. This includes a total

of approximately 35 relatively ‘high

priority’ components located throughout

all four lock corridors. The unreliable

system costs are considered conservative

in that they assume that vessels incur no

return trip and unloading costs, no vessel

idling costs, no stockpile depletion costs,

no plant shutdown costs, and assuming

unmet tonnage flows are able to acquire

alternative mode transportation (when

needed) at their long-run least-costly 

Maintaining the Infrastructure

FIGURE 5.8

Scheduled costs under the reliable system scenario versus expected unscheduled

repair costs and transportation costs from under funding the priority components

Millions

2050

2010

2014

2018

2022

2026

2030

2036

2038

2042

2046

Proactive Maintenance Costs

Unreliable System Costs

$70.0

$60.0

$50.0

$40.0

$30.0

$20.0

$10.0

$0.0

Great Lakes St. Lawrence Seaway Study 93
all-overland alternative rate. This comparison shows the

value of scheduling the expenditure needed to maintain

system reliability in a proactive manner. Totaling these

projected costs through 2050 shows that approximately

$1.2 billion in costs can be avoided by ensuring a proactive

approach to system maintenance is followed in order to

minimize the potential for system disruptions.

CONCLUSIONS

To determine an optimal strategy for maintaining the

GLSLS system infrastructure, one must understand or

forecast issues such as the following:

• The current state or condition of all components 

of the lock infrastructure;

• How likely is it that a particular component will fail

given its condition and level of use at a particular

point in time, and if a failure occurs what is the

impact – a lock closure (15, 30, 90, 180 days?), a

shutdown?, and what is the costs of repairs?

• What shippers will do if a discrete lock closure does

occur – wait or route the shipment via an alternative

mode and at what cost?

• How will a closure affect the costs of transporting

cargoes and will it result in a vessel making fewer

trips in a given season?

• How will shippers react if there is a perception of

existing system unreliability?

In addition to the above issues, there are related factors

that must also be considered, such as:

• How traffic will evolve over the next fifty years

through the system (by cargo type, origin and

destination)?

• How the vessel fleet will change over time and will

there be new types of vessels using the system?

• How vessel operating costs, including fuel costs, will

change over time?

The various databases, forecasts, and suite of lock risk

and vessel simulation analytical tools developed as part

of the GLSLS Study can be used to help inform and

support the infrastructure maintenance optimization. 

It allows planners to assess over a fifty year time horizon

the additional costs associated with a more intensive

maintenance regime and to determine if the value of 

the economic benefits associated with a proactive

maintenance strategy exceed these additional costs.

The general conclusion to be drawn from the study

analysis, which considered the reliability and risk

associated with those system infrastructure components

categorized by the Engineering Working Group as high

priority, is that a proactive maintenance strategy is

preferable to avoid the additional costs of unscheduled

maintenance repairs and general system unreliability.

The real benefit, however, lies in avoiding the

additional costs associated with unanticipated failures.

Infrastructure failures yield higher transportation costs

because vessel transit times are longer as a result of

waiting and queuing; shippers switching to alternative

more expensive transportation modes during closure

events; and, in the long run, switching to more

expensive modes if they perceive that the system is

unreliable. A more reliable GLSLS system with less

disruptive lock events (delays, closures, speed reductions,

etc.) is likely to attract more commercial traffic, which

will, in turn, make the system more cost-effective.

Chapter 5

94 Great Lakes St. Lawrence Seaway Study
CHAPTER 6

Opportunities and Challenges

Continuing growth in international trade, regional population,

economic activity, and highway and rail traffic will eventually increase

congestion in the bi-national transportation network that 

serves the Great Lakes basin and St. Lawrence River region. 

With additional capacity available, the Great Lakes St. Lawrence

Seaway system can help to relieve some of the pressures on landside

corridors by expanding into container service and shortsea shipping to

provide new intermodal services, particularly around road 

and rail bottlenecks. By addressing the stated preferences of shippers

and deploying the right kinds of new vessels, the system can improve 

its intermodal competitiveness and make significant new contributions

to regional transportation needs in the near future.
As part of its mandate to examine the current and future

commercial role of the GLSLS system, the Economic

Working Group of the GLSLS Study considered the

potential impact of new types of cargoes and vessels on

the system. A primary objective of this investigation was

to develop insights into the future role of the system

within an integrated North American transportation

network, along transcontinental as well as regional trade

corridors. The investigation included an assess ment of a

wide range of interrelated issues including: trade growth,

evolving and emerging markets, changing trade patterns,

shortsea shipping, modal integration, new vessel

technology, economic efficiency and associated

infrastructure needs. 

The role that the GLSLS system will play in the coming

half century is being determined by the interaction

between external and regional economic forces as well

as regional system-oriented actions undertaken to

accommodate the resulting transportation demands. 

It has become clear that the GLSLS can continue to

play a pivotal role in the economy of the Great Lakes

and St. Lawrence River basin, but only if its infrastruc -

ture evolves in a way that satisfies the transportation

needs anticipated in coming decades. Consequently, 

it is vital to understand the interrelated forces driving

regional economic growth and the transportation

industries that support it. 

THE GLOBAL CONTEXT

A significant external force transforming transportation

needs around and through the GLSLS system has been

the explosive growth in North American international

trade and investment. In part, this is due to integrative

forces that have led to increased economic globalization:

trade barriers are falling, electronic communication is

linking the world’s markets, and new technologies in

intermodal transportation networks are making it easier

to move goods and services around the world. As a

result, countries such as China and India are able to find

new North American markets and enter onto a path of

rapid development and growth.

The economies of the Great Lakes and St. Lawrence

River are already strongly integrated into the global

economy, in part because of the waterway linking it to

world markets. As a result, the binational region has

already experienced remarkable growth in its trade:

adjusted for inflation, it grew twenty-fold from 

$50 billion in the 1960s to $1 trillion in 2000. 

96 Great Lakes St. Lawrence Seaway Study

In recent decades, the rapid expansion of trade with

Asia has led that relationship to overtake traditional

trade ties to Europe. Even so, all trading relationships

have grown at extremely high rates. The explosion of

trade with every part of the world is transforming the

character of what used to be a bi-national regional

economy. In fact, the Great Lakes and St. Lawrence

River region is now a major market and transshipment

center for global exports as well as imports flowing

through Pacific, Atlantic and even Gulf Coast ports.

As these trading relationships continue to evolve, forecasts

suggest that the region’s gross domestic product (GDP)

will more than double, growing from $6 trillion in 2005

to $14 trillion in 2050 (see Figure 6.1). This boom is

likely to be accompanied by growth in the region’s

population. This growth, however, is dependent on the

continued diversification of the region’s economy and

the develop ment of technology-intensive and highly

competitive businesses, since many older more traditional

manu facturing activities are likely to move offshore. 

Global trends in containerization

Parallel to the rapid expansion of international trade,

there has been explosive growth in global container

traffic over recent decades. The Asia-Pacific region in

general and China in particular are leading this upsurge

by rapidly developing containerized transportation

markets. As China and other Asian countries are

significant trading partners with the U.S. and Canada,

this is having a dramatic impact on containerized traffic

through major North American ports, especially on the

Pacific coast. Trade with Asia generates the highest

containerized cargo volumes in the world and largely

defines the container shipping industry. China is already

the world’s largest single exporter of containerized cargo

and is soon expected to become the fastest-growing 

Chapter 6

Trillions of 2000US$

0

2

4

6

8

10

12

14

16

18

2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055

Year

High scenario

Most likely estimate

Low scenario

FIGURE 6.1

Projected growth in gross domestic product of the GLSLS region
importer of containerized trade. As Figure 6.2 shows,

world containerized traffic is expected to grow by an

average of 6.3 percent a year to reach 854 million

twenty-foot equivalent units (TEU) in 2020. 

China’s share of that traffic should reach approximately

33 percent, while North America’s share will grow at a

slower rate and account for 10.4 percent by 2020. 

In North America, as Figure 6.2 illustrates, containerized

traffic will grow at a slightly faster rate on the Pacific

Coast, which is expected to account for 55.5 percent of

all North American containerized traffic by 2020. Over

the same period, the Atlantic Coast is expected to account

for 36.6 percent of the continent’s containerized traffic.

Driving the growth in containerization are shipping

strategies that continually enhance efficiency by

reducing unit costs, using larger ships and calling at

fewer ports. Shippers are also looking for new alliances,

mergers and pooling agreements to optimize the use

made of their larger capacity. 

Containerization requires specialized ports with

appropriate water depth, handling facilities and modal

interchange capabilities. Ultimately, a handful of

deepwater hub ports with feeder services to shallower

regional ports could handle much of the international

container traffic destined for North America. To attract

Great Lakes St. Lawrence Seaway Study 97

increased containerized traffic, a port benefits from

proximity to the major markets, suitable physical

characteristics, availability of inland transportation,

competitive port charges and reliable port services.

With trade liberalization, Asian exports to the U.S. 

and Canada have grown rapidly. The introduction of

double-stack container trains in 1984 facilitated the use

of large post-Panamax vessels, and improvements in the

efficiency of inland rail distribution prompted an inter -

modal shift to transcontinental rail shipping, instead of

a previous dependence on direct all-water service to

American ports on the east coast. The increasing use of

rail and truck for inland distribution has been reinforced

by greater integration between container-handling systems

in ports and inland transportation. Over the last decade,

however, landside highway and rail networks are experi -

encing increasing strains as they strive to accommodate

continuing growth in containerized freight. 

REGIONAL TRENDS

The challenge of congestion

Within the Great Lakes basin and St. Lawrence River,

growth in population, economic activity as measured by

GDP and international trade means that private and

commercial traffic throughout the region will expand to

unprecedented levels. This will put significant pressure

on transportation networks. Forecasts prepared for the

U.S. Department of Transportation by its Federal

Highway Administration suggest that peak-period

vehicular congestion threatens to exceed the capacity of

the American national highway system, not only in all

major urban centres adjacent to the Great Lakes, but

virtually everywhere in the region. Canadian growth

patterns are similar and analysts believe that similar

levels of congestion may develop in the WindsorToronto-Montreal-Quebec City corridor. 

Planners have recognized the challenge and are trying to

respond. The U.S. Transportation Research Board has

even stated that highway capital stock is being added

faster than it is wearing out. Even so, the trucking

industry is keenly aware of and grappling with the effects

of local and regional congestion and capacity limits: 

• There is a shortage of skilled drivers, especially on

longer-haul routes, and the truck-driving workforce 

is aging.

• Trucking rates are now increasing, to factor in recent

increases in driver compensation, fuel prices and

insurance costs.

Opportunities and Challenges

World, North America and China containerized TEU traffic forecast 

0 

100 

200 

300 

400 

500 

600 

700 

800 

900 

1990 1995 2000 2005 2010 2015 2020 2025 

North America containerized TEU traffic by coastal region forecast 

0 

10 

20 

30 

40 

50 

60 

1990 1995 2000 2005 2010 2015 2020 2025 

Millions of TEU Millions of TEU

Year 

Year 

Pacific 

Atlantic 

World 

China 

North America 

FIGURE 6.2

Projections of world container traffic compared to that 

of North America
• More stringent security procedures at Canada-U.S.

border crossings impose a disproportionate burden on

the trucking industry, in terms of increased adminis -

trative costs and lower service levels to clients.

• Highway networks throughout the system are nearing

capacity, thus facing increased traffic congestion. 

• Some border crossings, such as Detroit-Windsor, are

also nearing capacity limits.

Efforts are underway to address these challenges, but it is

certain that most responses will add to costs in one way

or another, making the trucking industry less competitive

vis-à-vis other modes of transportation. This opens up

new opportu nities for both rail and water transport. 

Congestion on the highways is mirrored by congestion

in intermodal facilities serving ocean-going traffic. 

The growing demand for containerized services has led

to bottlenecks at the major North American Pacific

ports and along the rail and trucking networks to which

they are connected. In coming decades, limits to port

capacity expansion are anticipated at many west and

east coast ports. This problem is exacerbated by the

increasing size and draft of container ships, which cannot

be accommodated at many shallower coastal ports.

While new deepwater container port facilities are being

developed or proposed (i.e. Canada’s Prince Rupert and

Mexico’s Lazaro Cardenas, as well as the proposed

facility at Punta Colonet on the west coast), opportu -

nities for expansion at many existing west coast ports are

limited. In many areas, analysts fear that it will not be

possible to add new infrastructure

quickly enough to keep pace with

the even more rapidly expanding

needs of global trade.

One alternative is to re-direct traffic

to less travelled routes. Carriers

sailing from Asia-Pacific ports have

resumed all-water shipping via the

Panama Canal. As a result, that

waterway is now operating near

capacity and will not be able to

absorb more traffic until its current

expansion is completed by around

2015. When that happens, some

traffic will flow to American

southern and eastern ports to avoid

the congested west coast.

In addition, the Suez Canal route appears to be an

increasingly viable alternative. This is because of the

continuing expansion of North American trade with

Southeast and South Asian countries such as Malaysia,

Thailand, India and Pakistan. Moreover, the Suez Canal

(where no locks are needed to facilitate vessel passage)

can handle the larger and deeper draft Suez max vessels,

including recently deployed container ships that are too

large to fit even within the planned new locks of the

soon-to-be expanded Panama Canal.

Both these trends could favor the deployment of

additional container ships to North America’s east coast

ports. It is anticipated that at least 30 percent of West

Coast port growth will be diverted, half through the

Panama Canal and the other half via a round-the-world

route through the Suez Canal. Such traffic could

eventually find its way to east coast ports such as

Halifax, Nova Scotia, Norfolk/Portsmouth, Virginia, 

and Freeport, Bahamas.

As the map in Figure 6.3 shows, it is entirely feasible for

ships to leave Asian ports, sail through the Suez Canal

for potential stopovers in Europe, and then continue on

across the Atlantic to North America. Because ships on

the Suez route can be larger and carry both European

and American cargoes at the same time over very long

distances, vessel operators can seek greater economies of

scale. On the Great Circle route from the Straits of

Gibraltar to New York, deepwater ports such as Halifax

are in an ideal position to benefit from the forecasted

growth of trade with Asian ports west of Hong Kong via

Chapter 6

FIGURE 6.3

Evolving patterns of trade between Asia and North America

Established trade routes

Emerging Asia-Suez route

98 Great Lakes St. Lawrence Seaway Study
the Suez. Other east coast ports such as Norfolk, Virginia

have benefited from Panama Canal trade, but since the

Panama Canal is near maximum capacity, further growth

on that route will be severely constrained until Panama’s

expansion project is completed as scheduled in 2015. 

At the same time, Montreal will continue to remain

competitive vis-à-vis its traditional transatlantic trade,

which is currently carried in relatively smaller ships that

range up to the current Panamax vessel capacity of

4,500 TEUs. Montreal’s container traffic is also forecast

to grow significantly, if not at the potentially faster pace

of Asian traffic at a deeper draft port like Halifax. 

These pressures and trends may open up opportunities

for the GLSLS system. As the system is operating at

about half its potential capacity, it can be used to relieve

at least some of the traffic being added to the increasingly

congested roads and railways of the region. Exploiting

such opportunities requires investment to strengthen

intermodal linkages, the feasibility of which depends in

large part on the attitudes and preferences of the

transport service providers who use these networks.

Shortsea shipping

One way to ease traffic congestion is shortsea shipping.

The term shortsea shipping refers to the practice of

adding a waterborne leg to an intermodal shipment that

normally would travel by road or rail. The objective is to

reduce travel time, avoid congested routes and reduce

cost. It also holds out the promise of improving energy

efficiency and lowering greenhouse gas emissions. 

For example, goods that normally travel by truck

through congested metropolitan areas might be rerouted

across a lake, if fast and cost-effective water transport

were available. 

Taking advantage of this opportunity would involve

developing the capability of rolling the truck trailer

right onto the vessel and then rolling it off on the other

side so as to avoid lengthy stays in port as well as the

expense of loading and unloading cargo. That requires

investment in suitable roll-on, roll-off (Ro-Ro) vessels as

well as appropriate port facilities. As congestion on the

roads increases, this kind of investment may well be

worth making. To fully realize the potential for shortsea

shipping in the Seaway and on the Great Lakes,

American and Canadian hurdles to such services with

respect to taxes, user fees, and customs practices are

coming under reexamination. For example, legislation

providing for exemptions to the harbour maintenance

fee in the Great Lakes/Seaway system has been

introduced into the U.S. Congress.

Great Lakes St. Lawrence Seaway Study 99

Related to shortsea shipping are neobulk (or “break

bulk”) cargoes. Neobulk cargoes are often palletized and

typically rolled on or crane-loaded onto a ship. This

represents a cargo category that is neither a traditional

bulk good, such as iron ore, nor is it normally shipped by

container. It consists of commodities such as steel and

aluminum ingots, plate and coil steel, finished automobiles,

rail transportation equipment, farm machinery and

tractors, to take a few examples. Loading neobulk

cargoes into containers for shipping through containerhandling ports is an increasingly common method of

transporting such goods.

Because the trend in shipping is strongly toward

containerization, neobulks constitute a small and

declining freight category. In the U.S., containerized

cargo accounts for about 95 percent of all general cargo

import/export tonnage, leaving neobulks with only 

5 percent, a share that is declining. This market share

also holds for the Port of Montreal, where in 2005, noncontainerized general cargo accounted for 0.50 million

metric tons (Mt) or 4.3 percent of a total of 11.63 Mt.

The majority of this neobulk cargo consisted of imported

iron, steel and other metal products.

Neobulk shipments are characterized by very short

distance trips. Consequently, there are only a limited

number of movements that lend themselves to using the

GLSLS. There are, however, specialized trips that might

be developed for the future. For example, the amount of

neobulk traffic on the GLSLS might increase if there

were specific agreements between metal manufacturers

and carriers. As many steel and aluminum production

facilities in the Great Lakes region are located in close

proximity to water, some estimates suggest that the

GLSLS could attract as much as a 20 percent share of

the total traffic originating in such locations. For the

study’s base year of 2005, that could have generated a

total of 284 forty-foot equivalent units (FEU1) per day of

neobulk traffic on the GLSLS system, as compared to

the total forecast of 1,765 FEU per day for containerized

traffic, or 16 percent of the total. Their impact on

specific portions of the GLSLS could even be higher,

depending on the ability of GLSLS vessel operators to

capture flows from specific steel or aluminum production

facilities. Traffic of 284 FEU per day, however, is only

sufficient to support two or three north-south specialized

neobulk shortsea shipping operations. Given the

characteristics of neobulk traffic, such cargo growth

would be expected to level off by the period of 2030 to

2050, at which point it might involve the potential

operation of four to six specialized services.

Opportunities and Challenges

1 Two standards exist for container traffic: The twenty-foot equivalent unit, TEU, and the forty-foot equivalent unit, FEU. For shortsea shipping

analysis, the FEU is often a more appropriate measure of capacities and traffic levels since typical trucking and multimodal operations use FEU

and it is the number of FEU that typically controls drayage costs. To convert from FEUs to TEUs simply multiply by two. 
IMPACT ON THE GLSLS

TRANSPORTATION

NETWORK

Emerging opportunities

All of the drivers of change discussed above suggest that

there are opportunities for the GLSLS to capture larger

markets by focusing on new vessels and new cargoes.

Such opportunities would be based on growth in

container traffic through the system, supported by the

introduction of new vessels that are able to carry that

traffic more efficiently. The combination of

containerization and new types of vessels offers both

shorter travel time and lower cost, which can be

extremely appealing to shippers looking for alternatives

to their current transportation choices.

Containers and the GLSLS

Continued growth in domestic, cross-border, and

import/export trade means that traffic volumes could

soon be sufficient to achieve the economies of scale

needed to support a viable and competitive cargo vessel

service within the GLSLS system. In fact, all container

traffic through the region is expected to grow by a factor

of up to 2.5 times current volumes by 2050 and about

one-third of this could be moved using the waterway. 

As noted, congestion significantly raises truck and rail

transit times and costs, as both transport modes adopt

measures to accommodate an expected doubling in

traffic by 2030. This presents an opportunity for water

transportation, particularly if it can address the needs

and preferences of the shipping community.

The study’s Economic Working Group conducted a

modal diversion analysis which showed that with a

maximum open-water speed of 20 knots, container ships

on the GLSLS could have gained a market share of 

2 percent of total cargo traffic in 2005, a level comparable

to that of intermodal rail. Much of this market share

would have been on routes that are not well served by

rail intermodal services.

In an “uncongested” environment where the impact of

congestion on rail and highway is fully mitigated, water’s

share of total traffic in the region could still increase to

3 percent by 2050. If there is no investment in mitigating

highway congestion, a “congested” environment could

encourage both rail intermodal and water’s market share

to grow to more than 4 percent each, reducing truck

traffic to 92 percent. Since rail and water diversion

tends to be in long-haul traffic, this would result in

much more than an 8 percent reduction in haulage

distance. Figure 6.4 shows forecasted growth in the

container market for the GLSLS region under combi -

nations of congested/uncongested and moderate/high

growth scenarios. These are the markets for which the

GLSLS would compete with other available modes 

of transportation.

New service deployment

To determine the water routes on which such vessels

could be deployed, the GLSLS was divided into two

sections (see Figure 6.5). The eastern section consists of

the Canadian portion of Lake Ontario and the Seaway

downstream from the Welland Canal – essentially the

system from Hamilton to Halifax. The western section

consists primarily of the American portions of the upper

Great Lakes upstream from the Welland Canal – from

Chicago and Duluth to Hamilton. 

Chapter 6

Year 

20,000,000 

40,000,000 

60,000,000 

80,000,000 

100,000,000 

2000 2010 2020 2030 2040 2050 

Traffic in forty-foot

equivalent units (FEUs)

FIGURE 6.4

Forecast of market for container traffic carried by all modes in the

GLSLS binational region

Containers at port 

Source: U.S. Department of Transportation

100 Great Lakes St. Lawrence Seaway Study
In the eastern portion of the system, there is an

immediate opportunity for the GLSLS to carry domestic,

cross-border and import/export traffic at Montreal, as

well as a longer-term opportunity for extending GLSLS

vessel services to Halifax. The latter’s opportunity

depends on its ability to attract the larger number of

vessel calls that are expected to come from growth in

Suez trade with Asia. In the future, the ports of Halifax,

Quebec City and Montreal are all expected to see

increased traffic for both the American Midwest and

Central Canada, and so should grow accordingly. 

As for the western segment of the GLSLS, there are

substantial domestic and cross-border flows from Chicago

and eastern Wisconsin to Lake Erie ports, Central

Canada and Montreal. Given increasing congestion in

Chicago and the limited ability of railroads to expand

terminal capacity there, the Great Lakes could provide

by-pass service for some West Coast container traffic.

The Burlington Northern Santa-Fe (BNSF), Canadian

National (CN) and Canadian Pacific (CP) railroads can

extend freight service from the western ports of Tacoma,

Seattle, Vancouver and Prince Rupert to ports on Lake

Superior at Duluth and Thunder Bay. From there, an

intermodal transfer could be made to vessels that could

move this traffic to ports in the American Midwest. Thus,

there is an immediate opportunity to develop domestic

and cross-border traffic on the upper Great Lakes, and a

longer-term opportunity to develop land-bridge traffic in

conjunction with west coast ports and the railroads.

Great Lakes St. Lawrence Seaway Study 101

To realize such possibilities, the GLSLS could stake out

an initial position in the container business by using

individual small ships. As traffic grows, however, this

vessel traffic can be coordinated to operate as a single

network, thereby improving reliability and frequency.

Eventually, Seaway-max ships would replace the smaller

vessels. Implementation of vessel service should start by

focusing on attracting the domestic and cross-border

traffic that currently moves by truck in trailers rather

than in standard shipping containers, so a Ro-Ro trailer

service would be more conducive to its needs. Such

services would likely be a welcome complement to the

trucking industry given some of the challenges it is

facing with respect to driver shortages and delays at

border crossings.

Existing markets suggest that it would be feasible to offer

a service between Hamilton and Duluth or Thunder Bay

and Chicago as well as a daily service between Hamilton

and Montreal, using small Ro-Ro vessels. Such vessels

do not have the cost advantages of larger craft and they

would be vulnerable to a competitive response from rail

during the start-up period. However, Hamilton’s location

provides a drayage cost advantage to some shippers, which

could help protect the market share of water borne trans -

portation. A connection to American-based services at

Hamilton would provide an additional measure of

protection, since direct rail intermodal service is currently

not provided through the Niagara gateway, so crossborder traffic to Lake Erie would have to move by truck.

Opportunities and Challenges

Chicago

Milwaukee

Marquette

Sault Ste. Marie

Thunder Bay

Duluth

Superior

Cleveland Toledo

Toronto

Sarnia

Montreal

Halifax

Sept-Îles

Quebec

Ashtabula Detroit

Burns Harbor

Gary Harbor

GLSLS ports

Halifax to Hamilton

Hamilton to Chicago

Hamilton to Duluth

Montreal to Hamilton

(seasonal train route)

Hamilton

FIGURE 6.5

GLSLS vessel routes
There is also a market for largely domestic American

freight moving from Lake Superior to ports on Lake

Michigan and Lake Erie. A small vessel could shuttle

traffic from Duluth and Thunder Bay to Cheboygan,

where a connection would be made to a larger ship that

would serve both lakes Michigan and Erie.

The strongest current GLSLS traffic flow is American

domestic and cross-border traffic from Chicago and

eastern Wisconsin to ports on Lake Erie, with smaller

flows connecting to Lake Superior and Canadian ports.

Chicago and the ports of Wisconsin offer an attractive

opportunity for waterborne transportation that could

support a daily, large Ro-Ro vessel service at 2005 traffic

levels. A Chicago to Hamilton vessel service would

connect to Lake Superior service at Cheboygan and to

Lake Ontario and Montreal service at Hamilton.

Filling a single GLSLS-max Ro-Ro vessel daily to its

capacity of about 700 TEUs would nearly double the

volume at the Halifax port. While the traffic currently

available at Montreal can sustain a small vessel service

from Hamilton to Montreal, a major traffic influx at

Halifax would permit extension of GLSLS service all the

way to Halifax, and a large vessel could be substituted

for the small one. Another example is the development

of land bridge traffic at Duluth and Thunder Bay, which

depends on the cooperation of the west coast ports, the

BNSF, CN and CP railroads connecting to them, and

the interest and willingness of ocean carriers to use

GLSLS shipping services. 

DETERMINANTS OF NEW

WATERBORNE SERVICES

Shipper preferences

Any projected enhancements to the transportation

routes or services used in the GLSLS will ultimately

depend on the attitudes and preferences of the shipping

community that uses them. The GLSLS Economics

Working Group conducted a survey of shipper preferences

to determine the feasibility of the proposed innovations

to the system. 

Because of ongoing growth in global trade, the transport

industry operates in a highly competitive environment.

A survey of shippers found that almost all of them 

(99 percent) rated cost as an important or very impor -

tant attribute in their choice of transportation modes.

Time and frequency were rated as important or very

important by 89 percent of the shippers surveyed, and

98 percent rated reliability as important or very important.

102 Great Lakes St. Lawrence Seaway Study

Further analysis showed the trade-offs that shippers of

different goods were willing to make to obtain the level

of service that was important to them. For example, all

shippers say that time is an important consideration in

their planning, but when asked how much they were

willing to spend to save one hour of freight shipment

time, those typically moving finished goods in containers

and trailers were willing to spend more than those

moving raw materials. And those who shipped goods by

truck assigned a far higher value to time than those

shipping by rail or water. 

The same pattern held in attempting to estimate the

value of frequency and reliability in terms of the

premium shippers, who were willing to pay in order to

ship immediately or to guarantee the shipment. In both

cases, the shippers of finished goods assigned higher

values to frequency and reliability than shippers of

unfinished goods. 

Finally, shippers were asked about the extent to which

they value the ability to use a single mode of transporta -

tion all year round. This is significant because part of

the GLSLS system is affected by seasonality inasmuch as

the St. Lawrence Seaway is closed for roughly three

months of the year. The issue is what kind of a discount

could persuade shippers to switch from an all-season

mode to a seasonal mode, should it become available.

The answer is that for raw materials shipped by rail, a

discount of 5 percent in transportation costs would be

sufficient to induce a switch to the seasonal mode. 

For food, semi-finished and finished goods, the required

discount would be 14 percent. The least flexible

commodity is food shipped by truck, which requires a

discount of nearly 25 percent before it would switch 

to a seasonal mode, probably because of the highly

specialized nature of the equipment needed to transport

it. Otherwise, seasonality was found to be of less concern

to most shippers because they draw up their transport

contracts according to spot markets, monthly arrange -

ments or on short terms, and thus for them switching to

other modes is less problematic.

Shipper attitudes suggest that the GLSLS is highly

competitive against road and rail in the transport of

semi-unfinished goods. As the global economy grows,

the challenge for the GLSLS is to capture a share of this

expanding market, using its competitive advantages to

provide a valuable complement to multimodal transport

services based on road or rail. One way of doing so is to

address the service factors that shippers value in moving

semi-finished and finished goods as well. That means,

above all, reliability, shipment time and cost.

Chapter 6
New vessel technologies

Since shippers value cost and time, the GLSLS can

successfully compete against road and rail, if it deploys

vessels that are cheaper and faster. There are four new

vessel technologies that offer these advantages and can

be used to move containers on the GLSLS system: 

Containers on barges is a term used for

flat-bottomed barges that can move

stacks of containers through the system.

Such vessels consume usually little fuel, making them

relatively inexpensive. On the other hand, they move

very slowly.

Container ships are now available that

have a cruising speed that is almost

double that of older vessels. Although

their energy consumption is higher, the faster vessels are

still very energy-efficient when compared to truck, rail

and even container on barge services because their higher

energy consumption is offset by savings in crew and

capital costs. Higher speeds directly address shipper

concerns about time, making this mode competitive

against ground transportation. Ship speeds will still be

limited by locks and channels; but on open water, faster

ship speeds reduce travel time significantly.

Fast freighters (or ferries) use very

powerful engines to operate at high

speeds. They are often used as automobile

and truck ferries. Speed, however, is achieved through

high fuel consumption: they can use almost 20 times

more fuel per FEU-mile than a container ship. That also

means that a fast freighter (ferry) consumes substantially

more fuel per container shipped than does a truck for

the same distance. 

Great Lakes St. Lawrence Seaway Study 103

Partial air cushion support catamaran

(PACSCAT) is a surface-effect ship – 

a vessel that uses an air cushion to

partially lift itself out of the water. This reduces the draft

of the vessel as well as its wakes. The vessel operates in

water displacement mode at lower speeds but raises itself

out of the water for faster travel. Again, its higher speeds

are achieved at the expense of fuel efficiency.

The performance characteristics of the four vessel types

are summarized in Table 6.1. In terms of optimizing

container traffic on the GLSLS, the two critical parameters

are: fuel economy, expressed as the weight of fuel needed

to move one twenty-foot container (TEU) a distance of

one kilometre; and transit times between different ports

on the system. A comparison of these two factors

suggests that container ships specifically designed for the

GLSLS offer the best fuel economy, coupled with transit

times that are competitive with those of rail. 

Table 6.1 does not yet tell the full story since it does not

include cargo costs. Actual costing, however is derived

from highly complex calculations that factor in variables

such as capital cost of the vessel, amortization and

depreciation schedules, average speed given locks and

channels, crew size, and time spent loading and unloading

cargo as well as the fees and charges levied to pay for a

wide variety of support services. Container and other

vessels can be configured either as Ro-Ro, in which the

vehicles carrying containers (trucks or rail cars) can simply

roll on or roll off the vessel, or lift on/lift off (Lo-Lo), in

which cargo has to be physically lifted (usually by crane)

from the land-based vehicle and loaded into the vessel,

and then lifted out again for reloading onto a truck or

rail car at the other end. Clearly the time spent on the

process of loading and unloading cargo plays a role in

overall costs. 

Opportunities and Challenges

TABLE 6.1

Performance characteristics of potential new vessels

Performance Container GLSLS Fast PASCAT

parameter on barge container ships freighter (open water)

Top cruise speed (km/h) 14.8 37 63.9 63.9

Fuel consumption at cruise speed (kg/hr) 560 2,680 6,510 8,683

Fuel consumption (kg/TEU-km) 0.061 0.054 1.07 0.647

Loaded TEU/FEU capacity 620/310 1330/665 95/42 210/105

Crew 9 14 9 11

Transit time between Lake Erie and Montreal (hours) 48 43 40 37 

Transit time between Halifax and Montreal (hours) 84 50 25 25 

Transit time between Halifax and Chicago (hours) 202 135 86 83 
When all of these considerations are factored into the

calculation, transportation using container ships

customized for the GLSLS continue to be the optimal

choice in today’s competitive environment. They can be

designed in both small and large versions and can carry

international and domestic traffic. A smaller ship could

be deployed initially and could eventually be replaced

with a larger ship once traffic levels are high enough to

maintain daily service. Additional vessel frequencies

would be added on an “incremental” basis to increase

capacity as needed. To compete with ground

transportation, however, daily service frequency must 

be maintained.

New cargo and new vessel forecasts

The Economic Working Group developed forecasts for

the four different vessel technologies under consideration,

using both congested and uncongested traffic scenarios

and assuming moderate economic growth. Additionally,

high and low economic growth scenarios were developed

as sensitivities to the congested large ship scenario. 

The results of the analysis indicate that modern

waterborne technology can compete with rail and truck

for inland container distribution from Halifax, Montreal,

Duluth and Thunder Bay, as well as for domestic traffic

moving across the system. The most promising waterborne technologies are small and large 20-knot

container ships that can carry both international and

domestic traffic.

Forecast traffic volumes for the GLSLS are significant.

For a large container ship service at the demand levels

seen in 2005 and under current market conditions,

traffic through the GLSLS could reach as much as 

0.6 million FEUs, split equally between international

and domestic traffic. If congestion increases throughout

the system, this traffic could grow to more than 

3 million FEUs by 2050. 

On the basis of this analysis and considering all fore -

casting limitations, assumptions and institutional issues

raised, there is a strong case for further development of

plans for both sections of the GLSLS, particularly as

regards Lo-Lo and Ro-Ro container ship scenarios. The

planning needed includes further business studies to:

• develop investment grade traffic forecasts; 

• consider the potential for public-private partnerships;

and 

• explore sources of funding and financing of port and

intermodal development with a view to providing

incentives for infrastructure development by local

port authorities. 

104 Great Lakes St. Lawrence Seaway Study

These studies should also include a further detailed

assessment of vessel operations and costs, port and

hinterland services, and the potential of niche market

opportunities including ferry operations, neobulk

services, railcar ferries, and accompanied truck and

trailer services.

Constraints and assumptions

Forecasts of potential opportunities are largely an

extrapolation of historic trends and projected GDP

growth. Those trends, however, may not continue as

expected. For example, it may turn out that the growth

of trade with Asia will slow. If this occurs, it would

affect the volumes of traffic overflowing from west coast

ports onto other trade routes. 

The forecasts are also sensitive to assumptions relating to

the diversion of Asian traffic via the Suez route through

northeast ports and the willingness of the railroads to

cooperate in the development of land-bridge services

from the Pacific Northwest to Duluth and Thunder Bay.

Increased traffic through Halifax is an important

component in the viability of container movements

through the Seaway. There is also a need for further

examination of the extent of congestion at U.S. ports,

its likely impact, and possible mitigation strategies. 

Intermodal-rail service will provide major competition,

but GLSLS-max vessels could offer an advantage,

particularly on American-oriented traffic from areas

where rail container service is poor. It is assumed that

the railways will continue to focus on long-haul

container movements through rail mergers, but public

policy decisions for new port facilities and changes in

the structure of the railway network could affect shorthaul and mainline routing options. If there were

significant changes in the U.S., the forecasts for water

movements would have to be revisited.

It is assumed that Suez express ships would be willing to

unload Midwest bound freight at Halifax. Halifax would

be competing with New York, particularly if “double

stack” container routes between New York and Ohio

were promoted. Similarly, new port facilities with rail

connections to the Great Lakes could divert traffic away

from the Seaway to the American northeastern ports. 

Chapter 6
All the new services proposed depend on extended

container shipping through the Seaway to Montreal and

Halifax. Competition will remain strong from trucking

(shorter distances) and rail (long haul). It has been

estimated that any significant diversion of traffic to the

water mode would require vessels to maintain minimum

open-water speeds of 20 knots. It also means that much

of the initial diversion of market share will be in areas

not well served by intermodal rail. Further business

planning studies are needed to develop investment grade

traffic forecasts, assess potential public-private partnerships,

and evaluate port and intermodal port financing.

Environmental considerations

The opportunities described in this chapter will lead to

an increase in traffic flows within the GLSLS. This, in

turn, could have an impact on the environment unless

appropriate measures are adopted. At the most basic

level, increased traffic will mean more emissions from

ship engines, though it should be noted that this effect

could be offset by reductions in land-based transportation

emissions as some traffic growth is diverted from land to

water. Clearly, there is scope for ensuring that vessels are

more fuel-efficient and equipped either to control

emissions or burn cleaner fuels. 

Similarly, the wakes from increased vessel traffic will put

additional pressure on eroding shorelines. Again, these

impacts could be mitigated through measures such as

adjustments to ships’ speed. 

Bringing additional seagoing vessels into the GLSLS

could pose a challenge with regards to aquatic nonindigenous species (NIS), unless there is careful monitor -

ing and enforcement of regulations pertaining to the

discharge of ballast water. Increases in shortsea shipping,

however, do not involve external ballast water and thus

would have no aquatic NIS impact.

Finally, more traffic will inevitably require either more

maintenance of existing infrastructure, or the development

of new port and other facilities to handle increased

volumes and new cargos, such as containers. The main -

tenance or construction activities involved will be

accompanied by additional environmental implications. 

All of these impacts will have to be anticipated and

mitigated in any planning for new opportunities. On the

other hand, it should also be stressed that there will be

beneficial impacts on the environment if road traffic is

diverted to water routes that are relatively more fuel

efficient and emit lower levels of greenhouses gases. 

Great Lakes St. Lawrence Seaway Study 105

Engineering considerations

The scenarios described above have no direct implications

for the existing lock systems since the vessels proposed

would all fit within the current facilities. Additional

traffic volumes, however, could involve more ship passages

through the locks and thus greater wear and tear on these

facilities, thereby requiring more frequent maintenance. 

New cargos and new vessels, however, will require new

loading and unloading facilities. Many ports on the

GLSLS are not equipped to handle container traffic and

would require upgrades to their capabilities. That might

involve not just work in the port itself, but also

construction of road or rail linkages. Such upgrades

would require planning and financing in addition to

environmental impact assessments, as mandated by the

jurisdiction in which the work is to be done. 

CONCLUSIONS

Today, trucks move an overwhelming 98 percent of all

containerized tonnage in the Great Lakes basin and 

St. Lawrence River region. It is clear that the dominance

of trucking will continue into the future. However, it is

also clear that trucking is suffering from deteriorating

service because the roads it uses are becoming congested

by growth in automobile traffic, especially around major

cities. In the case of railroads, attempts to enhance

productivity over the past two decades have led to

increased concentration, amalgamation, and the

abandonment of secondary lines. As a result, moving

containers by truck and rail in the future should cost

more and probably take longer, since traffic is expected

to outgrow any improvements in capacity and congestion

is expected to increase. This opens up opportunities for

waterborne transport to capture a larger share of

commercial traffic through the region. 

Detailed analysis using conservative assumptions about

constraints to highway and rail capacity suggests that:

• The share of container traffic moved by truck could

decline from 98 percent to 92 percent by 2050

because of diversion of growth to other modes caused

primarily by congestion.

• The volume of containerized traffic carried by rail

could double from two to four percent by 2050 if the

railroads reintroduce unused capacity in secondary

lines and bypass routes.

• A competitive “marine intermodal” option could

accomodate four percent of containerized traffic by

2050, if it is competitive with rail and highway.

Opportunities and Challenges
All of this suggests that there are

opportunities for the waterway to

accomodate part of the container

traffic growth to the waterway in

selected transportation corridors. 

All of these assessments point in one

direction: as traffic volumes grow and

capacity limits are experienced by

other modes of transportation, the

GLSLS system can continue to play a

vital and probably expanding role in

the economy of the Great Lakes and

St. Lawrence River region. Even if no

changes are made and current trends

continue, the marine mode is likely to

experience slow and steady growth in

its existing mix of bulk and neobulk

cargoes. A more desirable outcome,

however, is that the GLSLS can be

positioned to capitalize on the

continuing growth in international

trade. It can attract more traffic and

emerge as a more effective component of the North

American intermodal network, providing alternative

routings to congested highways. In this way, it can

finally participate in the container revolution. 

All of these trends represent real and emerging oppor -

tunities that will provide an important new focus for the

GLSLS of the future. Realizing such opportunities will

not require new or different vessels: those shown to be

most efficient on these routes already exist. Taking

advantage of those opportunities, however, will depend

on maintaining current infrastructure, while investing in

facilities that can support emerging opportunities in

containerization, neobulk cargoes, and shortsea shipping. 

106 Great Lakes St. Lawrence Seaway Study

Chapter 6

Truck

2007: 35M FEU 

2050: 70M FEU 

Rail/Marine

92% 

8% 

98% 

2% 

FIGURE 6.6

Present and projected share of container traffic
CHAPTER 7

Policy and Planning 

In developing policies and plans for the future of the Great Lakes 

St. Lawrence Seaway system, it is necessary to balance several

different factors: the current and future economic potential of the

waterway, the condition of its infrastructure, the likely costs of

maintaining it, and its potential impact on the environment. 

Sound policy must provide for overall system efficiency, 

integration into regional transportation networks and 

optimization of infrastructure within the overall context of 

environmentally responsible and sustainable development. 
Through their diverse efforts, the three working groups

participating in the Great Lakes St. Lawrence Seaway

(GLSLS) study have arrived at a broad consensus

regarding the current state and possible future evolution

of the GLSLS system. 

The GLSLS system continues to play a decisive role in

the economic life of North America. It attracts a signifi -

cant amount of waterborne traffic. In addition, much 

of this traffic serves industries that play an important

strategic role in the economy. Since these industries are

integrated into value chains stretching into virtually

every sector, the traffic moved on the waterway has a

broad economic significance beyond the absolute

volumes of shipments.

The GLSLS system is situated within a unique freshwater

resource of major significance to the environment. 

This ecosystem is vulnerable to the overall stressors at

play. Factors such as urban growth, economic develop -

ment, commercial navigation, and recreational use have

all played a role in degrading the various ecologies 

in the basin. 

The GLSLS system is more than half a century old and

its infrastructure is beginning to show the signs of age.

While the majority of the system’s infrastructure remains

serviceable, the likelihood of component failure

continues to increase. In order to ensure uninterrupted

operations in the future, it is necessary to address those

components that would have the greatest potential

impact on the system’s integrity should they fail.

Chapter 7

ECONOMIC HIGHLIGHTS

• The waterway flows through two provinces and eight

states where 25 percent of North America’s population

is located. 

• The GLSLS is part of the continent’s largest inland

transportation corridor and carries traffic to and from

the industrial heartland. The system provides access to

half of Canada’s 20 largest ports and to numerous U.S.

regional ports of significance in terms of international

marine trade.

• Over the past decade, the system has carried an average

of more than 260 million tonnes of cargo every year.

• The volume of cargo, including strategic commodities

such as iron ore, coal, minerals and grain, is expected to

experience a modest, steady growth over the coming 

50 years.

• The GLSLS system has the potential to carry more

cargo, but there are currently impediments to

diversifying its traffic base.

• It is estimated that the waterway saves shippers

approximately $2.7 billion a year in transportation and

handling costs that they would otherwise have incurred

had they used other modes of transportation.

• The GLSLS is well placed to accommodate the new

vessels and the containerized new cargoes that will

dominate tomorrow’s international trade.

ENVIRONMENTAL HIGHLIGHTS

• The Great Lakes basin and St. Lawrence River region

encompasses the world’s largest freshwater ecosystem. 

• The most significant current environmental impact of

navigation through the GLSLS is associated with the

inadvertent introduction of aquatic non-indigenous

invasive species (NIS). Navigation is also associated

with other environmental impacts resulting from

channel dredging, the disposal of dredged material,

erosion caused by ship wakes, water level management,

and ships’ air emissions.

• These impacts are intertwined with a variety of 

non-navigational impacts that cumulatively affect the

environment in the GLSLS region.

• In recent years, greater awareness of the potential

negative impact of navigation on the environment has

led to the creation of various forums of discussion and

to the development of mitigation measures to manage

dredging, slow ship speeds in narrow channels, reduce

engine run-times, and reduce the possible inadvertent

introduction of aquatic non-native invasive species from

ships’ ballast water into the system.

108 Great Lakes St. Lawrence Seaway Study
Great Lakes St. Lawrence Seaway Study 109

FRAMING THE FUTURE OF

THE GLSLS SYSTEM

The GLSLS system is an incredibly valuable North

American asset. Marine transportation on the waterway

provides shippers with a safe, efficient, reliable and

competitive option for the movement of goods. However,

there is also unrealized potential in the system in terms

of the important future contribution it could make to

regional and continental transportation.

The fundamental understanding of the opportunities

and challenges acquired through the course of the

GLSLS study can be applied to identify priority areas

and develop a balanced approach across economic,

environmental and engineering factors, while addressing

four strategic imperatives:

1. What role should the GLSLS system play within 

the highly integrated North American transportation

system?

2. What transportation solutions are available to

guarantee a dynamic future for the waterway?

3. What measures need to be taken to optimize the

many different components of the system’s

infrastructure? and 

4. How should the GLSLS system sustain its operations

in a way that responds to concerns about environ -

mental integrity?

The following sections will consider each of these

strategic imperatives by summarizing the information

gathered through the GLSLS study and by presenting

some observations and key considerations.

Role in North American

transportation

North America is part of a global trade network that has

experienced explosive growth over the past two decades.

Part of this growth has a geographic dimension: East and

South-east Asia have emerged as major players in

international trade. Another part involves new types of

cargoes, travelling primarily in containerized vessels.

Both of these trends are having an impact on North

America as a whole and the GLSLS system in particular.

Policy and Planning

Container being handled at the Port of Montreal

Source: Transport Canada

ENGINEERING HIGHLIGHTS

• The condition of approximately 160 components of the

GLSLS system was examined: the review included

locks, approach walls, water-level control structures,

road and railway bridges as well as tunnels.

• Despite the system’s age, most of the components have

been kept in good operating condition and remain

serviceable. A criticality index was developed to identify

the highest priority infrastructure components through -

out the GLSLS system based on factors such as age,

current condition, availability of replacement parts, and

potential impact on navigation arising from failure. 

• The majority of the highest priority infrastructure

components are associated with the lock structures.

These were found to be of remarkably similar condition,

despite being located in different places throughout the

region and despite variations in construction and

maintenance methodologies.

• The age of the system infrastructure and several sitespecific conditions have resulted in a critical need for

capital investment to ensure that the system continues

to operate reliably in its current configuration. While

some of this investment is already being made, its level

is projected to increase significantly in the future.
As the volume of goods transported internationally

continues to grow, bottlenecks on North America’s west

coast are leading shippers to look for alternative routes

through both the Panama and Suez canals. Some of this

redirected traffic is finding its way into the Great Lakes

basin and St. Lawrence River. Yet the surface transpor -

tation routes in this region are already facing pressures.

Both roads and railways are strained in terms of increasing

congestion and tightening capacity. This is exacerbated

by the fact that most of this surface traffic is funnelled

through a small number of transit points, and security

requirements are slowing clearance procedures at borders.

Moreover, there is limited scope for the construction of

additional roads or railways to alleviate such congestion.

The inescapable conclusion is that waterborne traffic

could help to ease some of these pressures. The GLSLS

is currently operating with spare capacity that could be

used to redirect some traffic from overland routes.

Moreover, redirection of traffic through the GLSLS

system is directly connected with the other major trend

in international trade – the move toward containerization

of cargos. Much of the traffic now entering North

America consists of containerized shipping. As a result,

when it arrives at a port of entry, shippers have a choice

in how to move those containers inland inasmuch as

ships, trucks and railway cars are now all adapted to

carry containers.

Solutions for a dynamic future

The North American transportation system is more than

just the sum of its parts: it also involves linkages between

and integration of various modes and jurisdictions.

Within this context, the GLSLS system cannot be

thought of as a stand-alone mode restricted to one type

of traditional traffic.

The GLSLS can play an important role in contributing

another set of capabilities, while offering shippers

greater flexibility. In order to fulfill this complementary

role, policy and planning should focus on developing 

the waterway’s shortsea shipping potential to enhance 

its intermodal capabilities and its ability to handle

container traffic. 

110 Great Lakes St. Lawrence Seaway Study

In the past, container ships entering northeastern 

North America would either discharge cargo at the main

eastern seaboard ports or carry their cargo inland as far

as the Port of Montreal. Given the anticipated growth

in traffic on road and rail routes in the region, there is

an opportunity to move at least some portion of this

containerized cargo by water through the GLSLS system. 

For the GLSLS to emerge as a viable complement to the

movement of goods by road and rail, the system must

focus on enhancing and maintaining its competitiveness.

In the shipping industry, this is determined by a combi -

nation of factors: cost, time, frequency and reliability.

Clearly the cost per unit per kilometre or mile is a funda -

mental determinant of competitiveness. In this case,

waterborne shipping enjoys a clear advantage. That is why

it has been used to move large volumes of bulk goods. 

If waterborne shipping is to compete for more diverse

cargo traffic, however, it must also focus on the other

determinants of competitiveness. Total trip times need

to be shortened. Sailing frequencies need to accommo -

date shipper require ments. Unplanned closures and

traffic interruptions must be minimized. In fact, the

GLSLS system already has a good record in these areas,

but any additional improvements will enhance its overall

competitiveness and strengthen its position as a viable

transport alternative.

Chapter 7

OBSERVATION:

The GLSLS system has the potential to alleviate congestion on the road and

rail transportation networks as well as at border crossings in the Great Lakes

basin and St. Lawrence River region.

KEY CONSIDERATIONS:

• The GLSLS system is currently only operating at about half its potential capacity and is therefore under-utilized.

• Given projected growth in the economy and trade, all modes of transportation in both countries will be faced

with increases in traffic. When integrated with rail and trucking, the region’s marine mode can greatly increase

the overall capacity of the transportation system while reducing highway, railway and cross-border congestion.

• A research and development agenda would help to advance the use of new technologies to improve the

efficiency of marine transportation as well as strengthen its linkages to other transport modes. 
Optimizing the role played by the GLSLS within the

transportation system of the Great Lakes Basin and 

St. Lawrence River region requires a holistic view of the

entire system. Marine transportation must be integrated

seamlessly with the other modes in terms of cost, time,

frequency and reliability. 

To make this vision a reality, there are several aspects 

of modal integration that will have to be addressed.

There need to be highly efficient intermodal linkages at

the nodes of the system. The ports of the GLSLS system

must have suitable road and rail connections. They must

also have the right kinds of equipment to move containers

easily between vessels, rail flatcars and tractor-trailers.

There are other factors which come into play in this

area. There is a need for appropriate electronic tracking

and communication to direct and monitor shipments.

Policy and Planning

Great Lakes St. Lawrence Seaway Study 111

OBSERVATION:

A stronger focus on shortsea shipping would allow the GLSLS system to be more

closely integrated with the road and rail transportation systems, while providing

shippers with a cost-effective, timely and reliable means to transport goods.

KEY CONSIDERATIONS:

• Incentives need to be identified and promoted to encourage the

use of marine transportation as a complement to the road and

rail transportation modes.

• Institutional impediments that discourage the provision of

shortsea shipping services need to be addressed.

• Potential opportunities to encourage the establishment of crosslake shortsea shipping services could be identified on a pilot

project basis.

• The existing Memorandum of Cooperation and Declaration on

Shortsea Shipping, adopted by Canada and the U.S. in 2003 

and 2006, respectively, could be used to continue to advance 

the North American shortsea shipping agenda.

New technologies, improvements in traditional infra -

structure, streamlined border crossing procedures and the

harmonization of regulations will also be important in

designing systems and managing the demands of enhanced

interconnectivity across transport modes.

Advancing the concept of marine intermodal services

also requires suitable vessels adapted for different corgoes:

bulk commodities versus containers or neobulk

shipments. The routes travelled by the cargoes also need

to reflect the potential advantages of waterborne

transport. For example, shipping by vessel straight across

a lake can be preferable to moving goods around its

shore along congested roads. Apart from taking a faster,

more direct route, it may also be the case that border

procedures at the respective ports can be significantly

faster than those at highly congested land crossings.

Shortsea shipping

Source: Transport Canada
Optimizing the existing infrastructure

It is clear that the marine transportation infrastructure

of the GLSLS system involves more than just a series 

of locks. There are also ports and terminals, channels,

bridges and tunnels, systems for control and communi -

cation, as well as interfaces to other transportation modes.

Collectively, this constitutes an integrated system that

needs to be optimized if it is to contribute to solving the

transportation needs of the future. 

Each of the following elements represents a distinct set

of requirements, all of which need to be managed in an

integrated fashion to ensure the competitiveness of the

GLSLS system.

Locks: Because of their age, locks need to be subjected

to a maintenance schedule that deals with potential

failures in a way that sustains traffic with the fewest

possible interruptions and preserves overall system

integrity.

Shipping channels: The normal flow of water inevitably

carries silt deposits that must be removed to maintain

channels at authorized depths for shipping.

Ports: Ports and terminals that are likely to support

shortsea shipping or to serve as nodes in multimodal

networks will require appropriate loading and unloading

facilities and equipment together with seamless links

to other forms of surface transportation.

112 Great Lakes St. Lawrence Seaway Study

Chapter 7

OBSERVATION:

The existing infrastructure of the GLSLS system must be maintained in good

operating condition in order to ensure the continued safety, efficiency,

reliability and competitiveness of the system.

KEY CONSIDERATIONS:

• Any GLSLS infrastructure components identified as at risk and critical to the continuing smooth operations

of the system should be addressed on a priority basis.

• The existing GLSLS infrastructure requires ongoing capital investment to ensure that the system can

continue to provide reliable transportation services in the future.

• Modern technology, especially in areas such as control, should be used to maintain the GLSLS system in a

state that preserves its capability to respond to changing and unpredictable market conditions.

• The development of a long-term asset management strategy would help to anticipate problems with GLSLS

infrastructure before they occur and avoid potential disruptions that would reduce the overall efficiency and

reliability of the system.

• Investment options with respect to the system would involve numerous factors such as long-term planning,

innovative funding approaches, partnerships among governments and collaboration between the public and

private sectors.

Bridges and tunnels: There are a number of bridges 

and tunnels spanning the locks and channels of the

Welland Canal and Montreal-Lake Ontario section of

the Seaway that must be maintained in ways that do

not impede traffic. 

Control and communication: Logistics systems today

depend on advanced electronic systems to monitor

movements and track shipments in real time. 

Vessels: In addition to the traditional bulk carriers, there

will be a need for ships capable of loading, carrying

and unloading containerized cargoes.

While all of these diverse systemic elements form part of

an integrated whole, each demands its own investments,

technologies and scheduling. Planning must factor in

the specific requirements of each element in a way that

harmonizes the components of the whole system.

It is clear that burgeoning trade, a capacity crunch,

aging transport infrastructure and increasing pressures on

transportation lands in urban settings are an integral part

of the marine environment. The locks, ports, terminals

and other infrastructure of the GLSLS are now critical

components of North America’s transportation gateways

and, as such, they require investment and tools to

respond to market forces in a timely manner if they are

to continue supporting Canadian and U.S. international

and domestic trade. 
Environmental sustainability

The considerations noted above must be examined within

the framework of sustainable development. In simplest

terms, sustainable development means the ability to foster

economic growth in a way that does not cause undue

damage to the environment. Consequently, policy and

planning must factor in the environmental implications

of lock maintenance and repair, channel dredging,

construction of new port facilities, or the introduction 

of new vessels into the system. 

The ecosystem of the GLSLS system is vulnerable to the

stressors at play. Because many are not directly related to

navigation, management of or adjustments to navigational

stressors are important but would not necessarily result

in appreciable gains to overall environmental quality

unless they form part of an approach that is integrated

with measures in other economic sectors.

As the requirements of GLSLS operations and maintenance

involve some stressors to the Great Lakes-St. Lawrence

ecosystems, these must be managed effectively.

Organizational and governance frameworks, together

with accompanying policies and legislation, are likely

adequate to manage and control the navigation-related

activities that have a negative impact on the environment.

Policy and Planning

OBSERVATION:

The long-term health and success of the GLSLS system will depend in part 

on its sustainability, including the further reduction of negative ecological

impacts caused by commercial navigation. 

KEY CONSIDERATIONS:

• The GLSLS system should be managed in a way that prevents the inadvertent introduction and

transmission of non-indigenous invasive species and supports the objectives of programs designed to

minimize or eliminate their impact.

• The existing sustainable navigation strategy for the St. Lawrence River could be extended to the Great

Lakes basin.

• The movement and suspension of sediments caused by shipping or operations related to navigation should

be managed by developing a GLSLS system-wide strategy that addresses the many challenges associated

with dredged material and looks for beneficial re-use opportunities.

• Ship emissions should be minimized through the use of new fuels, new technologies or different 

navigational practices.

• Islands and narrow channel habitats should be protected from the impacts of vessel wakes.

• There is a need to improve our understanding of the social, technical and environmental impacts of 

long-term declines in water levels as related to navigation, and identify mitigation strategies.

• Improvements should be made to short- and long-term environmental monitoring of mitigation activities.

Great Lakes St. Lawrence Seaway Study 113

There have been considerable resources devoted to

research and planning but, with the exception of some

specific areas related to non-indigenous invasive species,

there have been few initiatives that have seen “on-theground” changes. There will be a continuation of

impacts related to planned works, such as maintenance

of infrastructure, maintenance dredging and placement

of dredged material, but such impacts can be minimized

through effective application of environmental

assessments, remedial actions, sound environmental

management strategies and best practices.

Yet sustainable development means more than just

selecting options that have a minimal impact on the

environment. At the broadest possible level, it means

attempting to build upon certain environmental advantages

of marine transportation over rail and trucking, as one

component of an integrated transportation system that

can be operated in a more environmentally friendly

manner. Transportation by water is significantly more

fuel efficient than other modes and consequently could

reduce the emission of greenhouse gases and other

pollutants. Moreover, increased utilization of waterborne

transportation could help to alleviate traffic congestion

on roads, which could ultimately result in the reduction

of road maintenance and repair costs. 
MONITORING FUTURE

PROGRESS AND SUCCESS

The success of any initiative to build the future of the

GLSLS system depends on a commitment by government

and industry in both Canada and the U.S. to clear

objectives and to the continuous monitoring of progress

and success. 

Canada and the U.S. should maintain their collabo -

rative efforts to plan the future of commercial navigation

on the GLSLS system through a binational body of

governmental representatives. The role of this body

would be to monitor the progress achieved in the areas

identified as priorities in the GLSLS study. The two

countries would work in partnership to pursue an

appropriate policy framework, promote the opportunities

represented by the system to other parts of government

and ensure an integrated approach to the distinct

imperatives of the economy, the environment and

engineering. Ultimately, the sustainability of the GLSLS

system depends on achieving a viable balance of these

three perspectives. 

The understanding gained from the expertise of those

who contributed to the GLSLS study can be used to

inform Canadian and U.S. decision-makers. The study

has identified observations and key considerations that

need to be taken into account in order to optimize the

operations and maintenance of the GLSLS system and

ensure it continues to serve North America’s economy

over the next 50 years.

Chapter 7

Engineering

(Maintaining

infrastructure)

Economy

(Supporting

economic

activity)

Environment

(Preserving

value

ecosystem)

Sustainability

Impacts &

implications

Costs &

Benefits Mitigation

INTEGRATING THREE PERSPECTIVES

114 Great Lakes St. Lawrence Seaway Study
CHAPTER 8

Conclusion

The Great Lakes St. Lawrence Seaway system can continue 

to play a vital role in the economy of North America, 

both by supporting strategic industries and by carrying the new

containerized cargoes dominating the global economy. 

Its future, however, depends on its reliability. 

The GLSLS Study has identified areas for future work. 

Success, however, will depend on balancing economic, 

engineering and environmental perspectives and securing 

the active collaboration of the many departments, 

agencies and stakeholders that have an interest 

in the region’s future.
The Great Lakes St. Lawrence Seaway

(GLSLS) system has played a vital role in

the economic evolution of North America.

Even before the completion of the system

that we know today, the St. Lawrence River

and the Great Lakes constituted a natural

highway into the heart of the continent.

For the past half century, the GLSLS has

supported strategic industries such as iron,

steel and energy, which serve as the

foundation of North American prosperity,

and there is every indication that this

essential role will continue into the

foreseeable future. 

North America’s continuing prosperity also

depends on its active participation in

international markets. Canada and the U.S.

must meet the challenges posed by the

rapidly changing dynamics of global trade.

International trade patterns manifest both increases in

volumes and changes in direction. Here too, the GLSLS

can play an important part, carrying the containerized

traffic that dominates global shipping and linking into

the new routes that are emerging as trade seeks

alternatives to congested traditional pathways. Situated

in the industrial heartland of North America, the

GLSLS links to all of the continent’s major ports of

entry and can thus play a key role in emerging trade flows. 

The GLSLS can therefore serve a dual purpose: it can

continue to provide an essential service to North America’s

resource, manufacturing and service sectors, and it can

play a growing role in carrying the new container traffic

moving into and through the region. Major industries

look to the GLSLS for both these functions because

waterborne transportation offers them significant

savings. If the system were not available, they would

find it difficult to shift traffic to an already congested

road and rail network. And the environmental

consequences of doing so would be far more severe than

those associated with operation of the waterway.

To satisfy regional transportation needs, the GLSLS will

have to offer multi-modal integration, flexibility and

cost-competitiveness. Above all, however, the main

conclusion of the GLSLS Study is that the system will

have to offer reliability. That means adopting an

operational and maintenance strategy that anticipates

and addresses potential problems before they interrupt

traffic flows. In today’s fast-paced economy, there is no

room for unanticipated interruptions. 

116 Great Lakes St. Lawrence Seaway Study

Conclusion

Forward planning must ensure that GLSLS capacity

remains fluid and responsive within a stable policy

framework and investment climate that can support

strategic and timely investment in system capacity, while

improving service levels and reliability. Furthermore, 

it must do so in a manner that satisfies concerns about

environmental stewardship and that raises challenges 

for the shipping industry.

All of this represents an ambitious undertaking. 

The GLSLS Study was a tremendous effort by a partner -

ship of seven departments and agencies. Its main

observations and key considerations, however, must now

be translated into specific action items. That will require

a commitment to implementation that is similar to the

Memorandum of Cooperation that initiated the current

process. Just as they led the initial effort, the two

governments will have to maintain the current

momentum to frame future specific actions in the same

spirit of collaboration. 

All of the initial partners have a stake and a role to 

play in maintaining the system’s economic viability,

preserving its physical infrastructure, and ensuring its

future environmental sustainability. Ultimately, however,

long-term success will depend on the participation not

only of these original seven government departments

and agencies, but also on the involvement of the

industries, not-for profit organizations and stakeholders

with an interest in the future of the region. 

Participants and stakeholders will succeed if they are able

to integrate the three perspectives of engineering, eco -

nomics, and the environment. Only if a balance is struck

among these three differing sets of imperatives will it be

possible to maintain truly sustainable commercial navi -

gation in the Great Lakes basin and St. Lawrence River,

and leave a lasting positive legacy to future generations. 
Great Lakes St. Lawrence Seaway Study 117
The Great Lakes St. Lawrence Seaway Study 

is a joint Canada/United States study 

to evaluate the infrastructure needs of the 

Great Lakes St. Lawrence Seaway system, 

specifically the engineering, economic and 

environmental implications of those needs 

as they pertain to commercial navigation.

Transport Canada

U.S. Army Corps of Engineers

U.S. Department of Transportation

The St. Lawrence Seaway Management Corporation

Saint Lawrence Seaway Development Corporation

Environment Canada

U.S. Fish and Wildlife Service