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106
pages
English
Ebooks
2014
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Obtenez un accès à la bibliothèque pour le consulter en ligne En savoir plus
Publié par
Date de parution
10 septembre 2014
Nombre de lectures
3
EAN13
9782897261320
Langue
English
Poids de l'ouvrage
6 Mo
Publié par
Date de parution
10 septembre 2014
EAN13
9782897261320
Langue
English
Poids de l'ouvrage
6 Mo
Prologue
For those of us who have an interest in Canadian history, and have not had the privilege of living on its shores, the St. Lawrence River holds a place of mythical proportions. It was the principal artery for setting foot on Canadian soil. It was the springboard from which explorers travelled both south and west, setting the stage for the first Europeans to see the Mississippi and the Rockies. Along its shores, and the Great Lakes that feed it, early settlements took hold and grew to become what is arguably the economic heartland of the continent. Its massive geographic footprint harbors some of the loveliest natural settings in North America, and some of its richest farmland. It contributes to the economy and the quality of life of hundreds of millions of people, and through its tens of thousands of kilometers of wetlands, it is the natural habitat of thousands upon thousands of species of unique flora and wildlife.
However, as well documented is this book, all is not well with the St. Lawrence River, not to mention significant parts of its watershed. Climate change is now increasingly impacting the quantity and quality of its water, and as a direct result, the wetlands on which so many other species depend. Along its shores, water levels are diminishing, and riverbeds are increasingly exposed. Mr. Gingras is to be commended for quantifying these symptoms, proposing bold solutions, courageously putting them into the public view, and setting the stage for a timely conversation.
As pointed out in this book, the consequences of reduced water flow in the St. Lawrence River, and by association, the Great Lakes, are huge, affecting hundreds of millions of people, and an impressive amount of wetlands and wildlife. From a technical perspective, Mr. Gingras invites us to ramp up our thinking, and think big, even though his proposals challenge our social, environmental and political values and priorities. As he so aptly points out, nature knows no political boundaries, and a key issue will be to convince all shoreline stakeholders, including the Canadian and U.S governments, provincial and state governments, local communities, environmental groups, wildlife conservationists and aboriginal nations, that remediation intervention is essential.
Unfortunately, while we attend to building this essential consensus, the problems described by Mr. Gingras will not go away. The consequences of either doing nothing or of following Mr. Gingras’ recommendations will both be complex and controversial. Also, time is of the essence. While we debate, nature can overtake our ability for timely intervention. The 1990s disappearance of the Newfoundland cod fishery for at least a generation should be a warning to all …
Regardless of what will ultimately be done, it is time for such conversations take place. Mr. Gingras’ book is an invaluable, evidence-based contribution to this important dialogue.
Richard J. Marceau, PEng, FCAE Vice President (Research), Memorial University of Newfoundland President, The Canadian Academy of Engineering (2012-2014)December 15, 2013
HYDROELECTRICITY, DESIGN STUDIES USEFUL UNITS OF MEASUREMENT
In order to make quick calculations for design studies, certain practical, albeit approximate, units of measurement were used.
Units
sq m or m 2 : square metre
cu m or m 3 : cubic metre
CMS or m 3 /s: flow rate, in cubic metres per second
km: kilometre
cu km or km 3 : cubic kilometre, for water volumes of reservoirs
MW: megawatt, a unit of power. For the lay reader, this is approximately equivalent to the output of an average-size locomotive. If a power plant is said to have a capacity of 100 MW, the reader will have some idea of the challenges involved.
MWh: a unit of energy, expressed as a MW per hour
TWh: one million MWh
Quick estimate factors
Flow : measured in cubic metres of water per second (CMS or m 3 /s)
If a flow of 31.6 m 3 /s fills a reservoir with one cubic kilometre of water per year, we can quickly calculate how much water is required or available in a reservoir.
Capacity : MW, or 1,000 kilowatts
The amount of power produced over a given period of time yields a unit of energy (MWh, TWy, etc.). If in one year (8,766 hours), a 114-MW power plant produces 1 TWy (1,000,000 MWh), we can quickly calculate its production in TWy. To calculate the capacity of a power plant, we must consider the output or efficiency of the turbine, alternator, flow rate, drop height (head) and several other factors, including loss of hydraulic load. In design studies, the head (m) × the flow (m 3 /s) × 0.009 provides a rough estimate of given capacity, accurate to within 1%. However, long water conveyance structures impact this estimate due to large hydraulic load losses
Energy cost
As in the 1900s, the industry still calculates energy costs in cents per KWh. To prevent errors and to quickly assess the financial challenges, at the design stage, of the alternatives presented, this study uses estimates in dollars per MWh.
Foreword
How to protect the St. Lawrence Basin from the effects of climate change
Climate change experts increasingly agree that the Great Lakes region will likely dry out at a rate of 20% to 30% over the course of the century. Environment Canada puts that figure at approximately 24%. Lake Huron and Lake Michigan have already dropped by more than 60 cm. Between Montreal and Quebec City, where the St. Lawrence River is shallow, with the exception of a narrow channel, the resulting decrease in flow of 1,500 to 2,200 m 3 /s could dry out 30% or more of the width of the river bed. In fact, over 18,000 km of shoreline and 1,000 km 2 of key wetlands, such as those of Lake St. Pierre and Georgian Bay, are endangered.
How can we prevent this phenomenon? And how can Quebec make the most of this situation when it alone can turn it around or at least minimize the threat?
About the author
F. Pierre Gingras has participated in the analysis and construction of major hydropower stations in Quebec for over 45 years. He served as the chief cost and planning engineer for Hydro-Québec dam construction for 32 years and was closely involved with the building of the Manicouagan-Outardes and James Bay complexes. In addition, he worked on the reconstruction of existing complexes on the St. Maurice, Bersimis, Gatineau, Beauharnois, and Ottawa Rivers, as well as on studies of various phases of some 200 other potential projects. Currently retired, he now conducts project studies for the Montreal Economic Institute (IEDM), the Canadian Academy of Engineering (CAE) and several engineering firms. His work has resulted in the Northern Waters project, the Pan-Canadian Power Grid project, the MacKenzie River Project and a project for the comprehensive management of the St. Lawrence River Basin, which stresses the need to mitigate the environmental effects of climate change already underway.
Part 1
Introduction
1.1 The current alarming situation of the St. Lawrence River
1.2 Climate change: anticipated effects
1.3 Mitigating the impacts of climate change: current options
1.4 St. Lawrence River management agreements and organizations
1.5 International Joint Commission
1.6 Freshwater: a global problem
1.7 Rising ocean levels
1.1 The current alarming situation of the St. Lawrence River
The current situation for the entire St. Lawrence River Basin is increasingly worrisome. In recent years, water flows in the St. Lawrence Basin and Great Lakes appear to have significantly decreased, which explains the low water levels of the Great Lakes and St. Lawrence River, as well as the operational difficulties for the Seaway and municipal freshwater pumping stations.
Lake Superior is already critically low. In reality, the topography is such that this Great Lake only drains a very small region, which is just a few dozen kilometres wide. The Sault Ste. Marie control structure plays a key role in maintaining Lake Superior’s water levels, and masks the effects of flow reductions.
Further downstream, Lake Michigan and Lake Huron are already some 60 cm below their natural historical levels, which is catastrophic for the environment. Their levels continue to fall at a rate of 3 cm or more per year. It is important to remember that Lake Huron and Georgian Bay are home to some of Canada’s most richly diverse and visited wetlands, which are protected by numerous wildlife and biological reserves. One sign that the situation may be worsening is that the flow of the St. Clair River has remained unchanged despite the dropping levels of Lake Michigan and Lake Huron. Could the weir be eroding?
Lake Erie and Lake Ontario already have mechanisms to control water flows and levels. However, the increasingly frequent need to draw water from these lakes to mitigate low flows in the downstream section of the basin implies that the water levels of Lake Erie and Lake Ontario are dropping despite the control mechanisms. Lake St. Francis, which is controlled by the Beauharnois complex, is experiencing the same problem.
Water levels in Lake St. Louis and the Laprairie Basin are also lower, but it appears that the natural weirs located downstream from the Lachine and Sault Normand Rapids are mitigating low flows to some extent.
The problem is spreading all along the St. Lawrence Basin, affecting both the Montreal region and the operational capacity of the Seaway.
The worst consequences are already being felt farther downstream along the St. Lawrence River, between Montreal and Quebec City. That section of the