This page has been archived on the Web

Information identified as archived is provided for reference, research or recordkeeping purposes. It is not subject to the Government of Canada Web Standards and has not been altered or updated since it was archived. Please contact us to request a format other than those available.

Skip booklet index and go to page content

Threats to Water Availability in Canada

Threats to Water Availability in Canada - A Perspective

Des O’Neill
DONMEC Consulting Inc., Lower Sackville, NS

Freshwater is a Limited Resource

With 7% of the earth's land surface, Canada possesses just about 7% of the world's renewable freshwater.

Freshwater is a natural resource, vital to the survival of all living things. In modern societies, it is essential to the functioning of a broad range of economic activities and sectors. Freshwater is a limited resource, however. Although Canada is commonly perceived as particularly fortunate in its plentiful freshwater resources, and Canadian people and industries are among the world’s highest per capita users of water, our apparent abundance of freshwater is relative rather than absolute. Our nation’s modest population in relation to its immense land area and correspondingly large water resource has much to do with the common perception of unlimited freshwater availability.

A Southern Population - A Northern Supply

Second only to Americans in their demands, Canadians use about 1650 cubic metres of freshwater per capita each year.more than double the average European rate.

In fact, many of country’s major river systems flow northwards, away from the regions of highest population density, and the increasing concentration of population in urban areas in the south has resulted in a growing mismatch between sources of freshwater and areas of highest demand. The present assessment of threats to freshwater availability in Canada should be seen, therefore, against the backdrop of a limited national resource, not always located in the right place and increasingly under stress from human and other influences.

Water - More Valuable than Gold?

Caledon, Ontario (pop. 40,000) relies on groundwater as its source of drinking water. The replacement cost of Caledon's drinking water service has been calculated at $33 million annually.

There can be no question that Canada’s freshwater supply is an immensely valuable national resource. Recent estimates of water’s measurable contribution to the Canadian economy range from $7.5 to $23 billion annually, values comparable to the gross figures for agricultural production and other major economic components. At municipal and sectoral levels, economic valuation is a more readily understandable and meaningful indicator, as illustrated in the case of the Town of Caledon, Ontario.

The accessible natural sources of freshwater include rivers, lakes, ponds and reservoirs, groundwater aquifers, snowpacks, glaciers, ice fields and, at the most fundamental level, the liquid and solid precipitation that feeds and replenishes all other sources. In Canada, as in other countries, all freshwater sources are now under noticeable pressure in the face of growing domestic requirements, and other, sometimes conflicting, demands. The needs of municipalities, agriculture and industry, for example, must increasingly be balanced against the necessity of maintaining adequate streamflows in rivers to support important aquatic ecosystems and fish populations. Climatic variability, extreme climatic events, and the spectre of climate change also threaten Canada’s sources of freshwater. At the same time, Canadians implicitly assume that governments will protect and sustain their sources of freshwater supply in the face of both population-related demands and natural and human-induced changes in important components of the supply system.

The present report examines individual and collective threats posed to freshwater availability. Based on contributions of participants at a workshop held in Victoria, British Columbia, in September 2002, it synthesizes the collective knowledge, expertise and input of about 100 academic, private sector and government experts in water science and water management. It presents a science-based assessment of the individual and cumulative implications of these stresses, and offers suggestions regarding the role science and policy might play in mitigating their impacts. It draws attention to the need for a more systematic and continuing implementation of established policies and strategies aimed at protection and conservation of water resources. Equally, it emphasizes the need for reinforced and expanded monitoring programs to observe and assess patterns and trends in water demand and use, and relevant environmental and ecosystem parameters. Finally, it examines the cumulative implications of the various pressures and stresses on Canadian freshwater resources and proposes an approach to addressing these threats in a more systematic and integrated manner.

Our current state of scientific knowledge on the hydrologic cycle receives considerable attention in the document, with particular emphasis paid to impacts of human activities, climate variability, and climate change. The worrisome implications of climate change for future access to freshwater in many regions are highlighted, as are the significant changes in important components of the hydrologic cycle that may result from a changing climate. These include changes in precipitation amount, type, geographic and seasonal distribution; in evaporation and evapotranspiration patterns; and in timing and rate of snowmelt. Assessment of the current and foreseeable capacity of climate science to produce useful predictions of future climatic conditions and of the related components of the hydrologic cycle is an important element of the present analysis. A companion publication1 released earlier addressed threats to sources of drinking water and to the health of aquatic ecosystems in Canada. The threats discussed there are inextricably linked to the threats facing freshwater availability, and, in reviewing this document, it is important to keep in mind that these have direct implications for drinking water supplies and ecosystem health.

Water Allocations, Diversion and ExportCommencing with a brief overview of the history of water management and use in Canada, Chapter 1 of the report discusses a broad range of related topics under the heading "Water Allocation, Diversion and Export." These include international and interprovincial apportionment (i.e., the quantitative division of streamflows among jurisdictions), magnitude, impacts and implications of interbasin diversions, the relatively new emphasis on protection of “instream” values, the controversial debate on water exports, and the potential influence of evolving aboriginal rights.

Dams, Reservoirs and Flow RegulationChapter 2 proceeds to examine dams, reservoirs and flow regulation from the perspective of the threats they may pose to the overall availability of freshwater. The impacts of dams and other impoundments on water quality, chemistry and thermal structure, river ice regimes, sediment load and deposition, and the integrity of aquatic systems are described. Among emerging issues, concerns are identified surrounding dam safety and decommissioning, as is the need to reassess these aspects in light of climate change and its future impacts on hydrologic regimes. Attention is also drawn to the contrasting perceptions of dams as sources of “clean” hydropower and as possibly significant sources of greenhouse gases.

A Changing Climate May Imply More Water Shortages

DroughtsHistorically most frequent in the southern Prairies, droughts are now a focus of scientific concern that climate change may increase their frequency, duration and severity in all regions of the country. Their causes and impacts, and their present and future implications for freshwater availability are addressed in Chapter 3. The current status of and future requirements for drought monitoring, modelling, and prediction are also discussed, as is the potential of drought adaptation strategies.

A Changing Climate Will Change Flood Patterns

FloodsAt the other end of the hydrologic spectrum, floods and flooding cause major human disruption and exert both positive and negative influences on natural systems. Floods impose direct and indirect pressures on the availability of freshwater by damaging infrastructure, contaminating water supplies, and changing patterns of groundwater recharge. Spring floods, fed by melting snow, are a notable feature of most Canadian rivers and streams. A warming climate may significantly change their timing and magnitude, particularly in southern regions of the country, directly affecting the seasonal and annual cycles of streamflow and freshwater availability. Chapter 4 of the report examines these and related issues, highlighting needs to reassess estimates of Probable Maximum Flood, to update flood risk zoning maps and other planning approaches, and to apply such tools more consistently in land-use planning.

Urban Supplies Are Already Under Stress

Municipal Water Supply and Urban DevelopmentUrban and residential requirements exert a primary demand on freshwater resources, and urbanization is proceeding at an accelerating pace in Canada. Urban expansion directly affects water availability for other sectors through its impacts on storage and runoff patterns and on water quality. Municipal uses now represent 11% of Canada's total freshwater consumption, with residential requirements contributing about half of that figure. During the 1994 to 1999 period, roughly 26% of Canadian municipalities reported water shortages as a result of increased consumption, drought or infrastructure problems. Notably, municipalities reliant on groundwater reported the most frequent supply difficulties.Chapter 5 examines the growing stresses placed on water supplies by urban and rural development. It also draws attention to various strategies used to mitigate these pressures, including demand management and increasing emphasis on reuse and utilization of lower quality water sources.

Manufacturing and Thermal Energy DemandsThe thermal power generation and manufacturing sectors are Canada's largest and second largest users of water, and the very large demands these activities place on the nation’s available supply are reviewed in Chapter 6. Factors affecting their future requirements for water are also addressed, emerging issues identified, and related policy, program and research needs highlighted. Among the emerging issues identified are the growing requirements of high-technology “new economy” industries for substantial amounts of high-quality water, possibly from already stressed municipal sources.

Agricultural Water Consumption Tops the Scale

Land Use Practices and Changes - AgricultureAgriculture is Canada’s largest net consumer of water, using about 70% of the water it withdraws from rivers, streams, reservoirs, and wells. Consequently, this vital sector exerts major pressures on the available water supply, particularly in the Prairie Provinces where 75% of all agricultural withdrawals occur. Chapter 7 examines trends in agricultural water usage and issues arising from agricultural water demands. It draws attention to the fact that about 85% of agricultural water use is for irrigation2 and that climate change is projected to increase this demand. It also points out that improved techniques such as irrigation scheduling and drip irrigation can yield substantial savings in water usage, and urban wastewater also has potential for irrigation of some crops.

Disappearing Glaciers - Reduced Streamflows?

Rocky Mountain glaciers that supply up to 10% of the base flow used for irrigation in western Canada may shrink dramatically during the next century!

Meltwater from Rocky Mountain glaciers is identified as an important contributor to baseflow in many western rivers and streams; consequently, predictions that these glaciers will disappear during the next century raise serious concern from the perspective of agricultural and other demands for water.


Forests are important...

Land-Use Practices and Changes - ForestryCanada possesses about 418 million hectares of forestland, about 10% of the world’s total, and the forest sector is a major contributor to the national economy. Forests play a vital role in the hydrologic cycle, influencing patterns of evapotranspiration, runoff and soil moisture. Disturbances caused by forestry operations and fires, however, exert significant impacts on streamflow, water quality, sediment discharge, and groundwater recharge. Chapter 8 examines forests and forest practices in relation to the contributions they make and the threats they pose to the nation’s water resources. The impacts on the hydrologic cycle of forest fires, insect infestations, and practices such as clear-cutting are reviewed. In addition, the important role played by forests in the global carbon cycle is discussed.

Is Oil More Valuable than Water?

The oil and gas industry in Alberta has the rights to 25% of the province's groundwater supply for use in the recovery of oil from wells.

Land-Use Practices and Changes - Mining and Petroleum ProductionThe Canadian mining and petroleum industries are among the world leaders in resource extraction. While mining places limited and location-specific demands on water supplies, the sector becomes a high-demand user of freshwater when associated refining, smelting and manufacturing operations are considered. Furthermore, the release of substandard water from abandoned mines is a significant threat to freshwater availability in some areas of the country. The petroleum sector, for its part, has large and growing requirements for freshwater. High-demand applications include extraction of oil from tar sands and injection of water into deep formations to enhance hydrocarbon production. The large amounts of wastewater from oilsands production are of poor quality and must be held in containment for long periods, while the injection technique results in permanent loss of water to other uses. Chapter 9 discusses uses of water by the mining and petroleum sectors, impacts of droughts, floods and climate change on their operations, and challenges faced by the industry in responding to increasing demands for resources in the face of more stringent environmental regulations and climatic variations and extremes.

Groundwater is a Hidden and Uncertain Resource

About 30% of Canadians rely on groundwater.municipal water shortages are most frequently reported by communities supplied from groundwater sources.

Climate Variability and Change - Groundwater ResourcesGroundwater is, as noted earlier, a vital component of Canada’s freshwater resource, supplying a substantial fraction of municipal, agricultural and other requirements for water. As outlined in Chapter 10, our knowledge of the groundwater regime is considerably more limited than is the case for surface water3 ; moreover, management of groundwater is often the responsibility of different agencies than those accountable for other water resource components. Consequently, there are both deficiencies in knowledge and institutional issues to be addressed in developing policies and strategies for management of groundwater.

Climate Variability and Change - Rivers and StreamsChapter 11 examines potential impacts of climate variability and climate change on water availability in rivers and streams. It reinforces the fundamental importance of systematic, long-term monitoring of hydrometeorological parameters in representative large and small watersheds in all regions of the country. Concluding sections stress the need for enhanced priority, sharpened focus, clearer leadership, and increased resources in addressing the potentially dramatic impacts of climate change on water availability in streams and rivers.

Canada - a Land of Lakes

Roughly 14% of the world's lakes larger than 500 km2 are located in Canada.

Climate Variability and Change - Lakes and ReservoirsCanada’s more than a million lakes cover about 7.6% of its land area and there are, in addition, over 900 major reservoirs. Lakes and reservoirs are vitally important sources of freshwater for municipalities, agriculture, industry, recreation and other activities, as well as being important ecosystems in their own right. Chapter 12 discusses impacts of climate change and increased consumptive use by humans on lakes and reservoirs. The authors identify and comment on the probable responses of these water bodies to climate variability and climate change, pointing out that there are variations in the sensitivity of individual lakes. They stress that climate scenarios derived from the present generation of climate models give grounds for concern that reductions in lake and reservoir levels may occur in the foreseeable future. Such reductions could result from changes in timing and rate of melt of snowpacks and glaciers, changes in precipitation patterns, and increases in evaporation associated with a warmer climate.

Canada's Peatlands May Be a Climate Time Bomb!

Canada's peatlands contain about 150 billion tonnes of carbon, about 25 times the amount of fossil fuel carbon released to the atmosphere worldwide each year.

Climate Variability and Change - WetlandsPoorly understood by the public at large, wetlands are vital components of the hydrologic regime, modulating discharge regimes in rivers, re-charging groundwater aquifers, and acting as reservoirs in the cycle of production, release, and storage of important greenhouse gases. In addition to being important ecosystems in their own right, they absorb, store and assimilate contaminants and provide many recreational opportunities. Canada’s wetlands occupy about 1,300,000 km2, an area slightly larger than the province of Ontario. Occurring primarily in the boreal and sub-arctic regions, peatlands are by far the most common type of wetland, representing about 85% of the total. As outlined in Chapter 13, the future stability of wetlands in general, and peatlands in particular, is uncertain in the face of a warming climate4 . This raises the spectre of dramatically increased releases of greenhouse gases to the atmosphere.

Quelques (Disappearing?) arpents de neige!

All of Canada is affected by seasonally frozen ground and half of Canada has permanently frozen ground (permafrost).

Climate Variability and Change - CrysophereDescribed by Voltaire as “quelques arpents de neige,” Canada’s global image is one of snow and ice through much of the year. In fact, the cryosphere--snow, ice, glaciers, permafrost and frozen ground--is one of the most important components of our physical and biological environment. Chapter 14 points out that phase changes and seasonal storage involving the cryosphere and cryospheric processes dominate the hydrology of most Canadian river basins. Melt from glaciers in the Western Cordillera, as noted earlier, makes a significant contribution to summer streamflow in rivers and streams. Ice cover exerts important influences on river and lake discharges, as well as on ecosystems, and affects timing and intensity of discharge, evaporation patterns, and local climate. The Intergovernmental Panel on Climate Change has projected that global climate warming will be greatest in arctic and sub-arctic regions. The cryospheric response to a warmer climate may be expected to include a decrease in solid precipitation, a reduction in the duration of snow and ice cover, gradual disappearance of mountain glaciers, increases in permafrost active layer depth, and melting of ground ice. Such changes will clearly have dramatic consequences for Canada and other high-latitude countries. Quantifying this response and its consequences, however, presents a significant challenge since current climate models are limited in their ability to simulate key characteristics of cold region climates.

Integrated and Cumulative Threats to Freshwater Availability are a Present Reality!

Integrated and Cumulative Threats to Water AvailabilityChapter 15 examines the challenging, but real-world issue presented by integrated and cumulative threats5 to freshwater availability, and the need to manage these growing and somewhat intractable pressures. The case of the Columbia basin is used to illustrate how independent decisions made in the past by narrowly mandated government agencies contributed to creation of a so-called "meta-problem" extending well beyond the scope of a single agency or level of government. In the face of the complex interrelationships presented by integrated and cumulative threats, the need for more broadly focussed, integrated and consultative water management strategies is stressed. The authors discuss mechanisms established as part of current attempts to address such meta-problems in the Prairie Provinces and the Great Lakes basin (e.g., the Prairie Provinces Water Board and Alberta's South Saskatchewan River Basin Water Management Plan, the Great Lakes Charter).


The individual chapters in this publication draw attention to many sectoral and crosscutting stresses or threats affecting the nation's freshwater resources, and identify where related gaps exist in our current scientific knowledge and understanding. They constitute substantive science assessments by experts in the subject areas addressed in these chapters. In the present writer's view, these science assessments point to needs for urgent and sustained action on a number of fronts to ensure Canadians have future access to adequate supplies of freshwater. The following sections, therefore, represent one individual's synthesis of major conclusions and recommendations from the report along with some thoughts regarding their implications for future policy development and decision making. In overview, these topics can be discussed under four headings:

Observational and Data Needs

To know what to must first know what is happening...

The systematic acquisition of observational data on Canada's freshwater resources represents an expensive and long-term commitment. Well-designed and solidly resourced monitoring programs are, however, absolutely essential to document trends in freshwater supply and use, to support research, and to measure and assess impacts of water policies and management and operational practices.

At the most basic level, the report identifies substantial shortcomings in our knowledge of Canada's freshwater resources, water usage patterns, and water-related infrastructure, pointing out, inter alia, that:

  • Our surface water, groundwater, precipitation, cryospheric and other relevant monitoring networks are inadequately resourced and poorly coordinated. Near-real-time streamflow observations are insufficient to support hydrological modelling applications; observational coverage6 has key thematic and regional gaps; there are no national groundwater or wetlands monitoring networks; and access to historic data, including paleoclimate and paleoflood records, needs improvement.
  • Reliable inventories of lakes and reservoirs, aquifer resources, glaciers, the condition and capacity of water distribution and treatment systems, and other important elements such as the number, size and location of mine workings and waste deposits are needed.
  • Water demand and usage patterns should be more systematically monitored in sufficient temporal and spatial detail to document sectoral uses, trends and variations, losses, and effects of weather and season. More comprehensive data are also needed on groundwater withdrawals, effluent quality, and ecosystem behaviour in receiving waters.

In summary, authors highlight significant deficiencies in the design, operation and coordination of Canada's surface water, groundwater and climate monitoring networks; in documentation of water demands, usage patterns, effluent quality, and ecosystem impacts; and in basic water resources inventories. Not surprisingly, therefore, they recommend intelligently targeted expansion of baseline monitoring for key components of the hydrologic cycle, representative water demand and usage parameters, and effluent quality and aquatic impacts. In view of this recommendation, it would seem urgent to undertake a coordinated national review of freshwater monitoring programs to identify specific deficiencies and develop prioritized proposals for corrective actions. While considerable rationalization of climate and hydrometric networks7 has recently been completed, it seems clear that integration and complementarity among various sectoral monitoring programs must be further stressed. Moreover, innovations in monitoring techniques such as satellite remote sensing should be more aggressively and systematically implemented. A valuable supporting initiative might be to develop and regularly disseminate easily understood indicators of the status of freshwater resources8 and their socio-economic importance, in order to enhance and sustain public awareness of water issues.

Critical Research Priorities

Scientific investigation enhances our collective capacity for critical insight, informed assessment and rational judgement.

It is widely understood that research is required to generate new knowledge, advance technologies, predict future resource availability and demand patterns, evaluate uncertainties, and assess risks and benefits of policies and strategies. An improved knowledge base is clearly essential for prediction of future threats to the available freshwater resource, and for development of more effective water management policies and practices. In the present context, the implications of climate variability and climate change for water resources and water demand and usage patterns represent over-arching concerns. Clarifying these implications should be a top-priority research challenge. Responding to this challenge requires improved simulations of future climate and more useful seasonal climate forecasts. In particular, authors recommend that:

  • the resolution of Global Climate Models (GCMs) be increased, representation of the cryosphere improved, and other appropriate steps taken to enhance their ability to model fields of hydrological importance. In short, Canada's world-class climate modelling capability should receive continuing support;
  • the physical causes of past droughts be clarified, and monitoring and modelling of drought conditions improved. Greater advantage should be taken of environmental prediction capabilities to provide early warning of incipient drought conditions, and improved drought adaptation strategies must be sought; and
  • the implications of climate variability and climate change for freshwater ecosystems, forest hydrology, permafrost distribution and melting of ground ice, peatlands/wetlands and glaciers be further clarified. A particularly important challenge will also be to factor climate change into flood frequency analysis and flood risk mapping.

On a more general level, authors recommend that research efforts focus on improved understanding and modelling of hydrological processes and systems, including aspects such as effects of land use changes on floods; relationships among land management, soil water balance and partitioning of precipitation; and flow of mine wastes through frozen soils. Greater emphasis should be given to synthesis and integration of research results using models that integrate hydrological and biogeochemical cycles; hydrological process knowledge must be progressively incorporated into watershed models; and up-to-date models applied to flood prediction, building on improving skill in forecasting excessive rainfall events. As supporting activities, improved remote sensing algorithms and statistical testing and diagnostic approaches should continue to be pursued.

Issues related to water quality also need to be addressed: for example, new chemicals of concern and their human and ecosystem health implications; drainage chemistry from mine wastes; and enhanced processes for water treatment, reclamation and recycling. Correspondingly, understanding must be improved of the social and economic factors underlying demands for water or posing impediments to innovation, conservation and recycling, and socio-economic models developed for various water uses and the forces driving demand patterns and recirculation decisions.

Requirements for Informed Policies and Effective Management

Scientific understanding provides a foundation for the development of farsighted policies and practices.

Implementation of farsighted policies and effective science-based management practices, reinforced by the support of a well-informed public, will be essential to a successful response to the many issues and challenges identified in this report. During the coming decades, the apportionment of water rights on cross-boundary rivers will require much greater attention in view of the growing potential for interjurisdictional conflicts. Optimal institutional frameworks must be sought that facilitate integrated land and water management, while striking a rational balance between competing uses, minimizing long-term threats to freshwater, and ensuring equitable allocation of water within basins and between jurisdictions. Financial approaches should be refined to ensure timely replacement of ageing water infrastructure. Coordination and cooperation among federal, provincial, territorial, municipal and private sector organizations in planning, installing and operating monitoring programs could be enhanced, and linkages between water scientists and water managers further solidified to facilitate application of new knowledge and techniques.

Science assessments provide a useful bridge between science and the needs of policy and decision makers.

Moreover, the concept of sustainable development requires us to consider intergenerational needs for freshwater. In consequence, public understanding and support must be developed through information campaigns that stress the fundamental socio-economic importance of freshwater, the limits to the freshwater resource and the need to conserve and protect it, outlining practical measures individuals and communities can take to that end.

The Leadership Challenge

Scientific leadership and teamwork are needed to address the many threats to Canadians' future access to freshwater.

At the most fundamental level, this report reinforces the need for strong leadership and an enhanced spirit of interjurisdictional and cross-disciplinary teamwork to address the urgent issues relating to Canada's future access to freshwater. Scientific leadership is clearly required to refine and prioritize requirements and obtain funding to implement needed upgrades to monitoring programs so that Canadians know, with confidence, the extent and condition of their freshwater resources, their socio-economic importance, the dimensions of the threats to them, and the effects of policies, management practices and external influences. Scientific leadership and vision are needed, equally, to target research efforts at issues truly critical to ensuring the nation's future freshwater supply. Furthermore, committed leadership and teamwork over the long term are needed at the highest levels of government to achieve improved coherence in policies and practices within and across jurisdictional boundaries.


In conclusion, this report lays out a challenge to develop and implement policies and actions to ensure the sustainability of Canada's freshwater supply in the face of the various threats and pressures outlined in succeeding chapters. Long-term political and institutional commitments will be essential if we are to respond effectively to that challenge. In consequence, the report's fundamental value will be largely measured by the degree to which it captures attention and motivates action by decision makers and institutions. Ultimately, success will have been achieved if the authors' efforts help to ensure Canadians have long-term access, at reasonable cost, to the freshwater needed for human consumption, sustainable social and economic development, and protection and conservation of aesthetic, environmental and other important values.


1 Environment Canada. 2001. Threats to Sources of Drinking Water and Aquatic Ecosystem Health in Canada. National Water Research Institute, Burlington, Ontario. NWRI Scientific Assessment Report Series No. 1. 72 p. RETURN

2 The remaining 15% being used in watering livestock. RETURN

3 Canada does not have a national groundwater monitoring network. RETURN

4 Permafrost degradation is already drastically changing the character of Canadian peatlands as the southern boundary of discontinuous permafrost moves northward.RETURN

5 Integrated threats emerge from combinations of stresses. Cumulative threats and impacts build and are felt over time. RETURN

6 Particularly for the cryosphere, in unregulated basins and in the North. RETURN

7 The establishment of a Reference Hydrometric Basin Network and a Reference Climate Network has resulted from these efforts. RETURN

8 The importance of readily understandable, high impact, snapshots of observed conditions cannot be over stated since requirements for continuing investments in long-term monitoring programs are not well understood by the public at large or by decision makers.RETURN

Date modified: