The importance of the watershed in our lives

Watersheds (also catchment areas, catchment basins, drainage basins)

A watershed is a tract of land where surface water from rainfall, streams, rivers and underground sources converges or flows naturally into a single, larger waterway called the watershed outfall (see Figure 1A) and ultimately makes its way into a major river or into the ocean.

Le bassin versant est en fait le territoire dont toutes les eaux de surface s’écoulent naturellement vers un même point appelé exutoire du bassin versant (voir la figure 1a). Le bassin versant comprend tous les éléments – vivants et non vivants – qui se trouvent à l’intérieur de ses limites, y compris le sol, la végétation, les animaux, les êtres humains, les eaux de surface et les eaux souterraines.

Un bassin versant remplit plusieurs fonctions importantes dans nos vies. Citons les fonctions hydrologiques, écologiques et socioéconomiques.

Hydrological role (movement, distribution and properties of water)

A watershed has three hydrological functions:

  • First, it collects water from the atmosphere through rain and snow, and several factors determine exactly how much of that water can infiltrate the soil, including soil type, topography (physical characteristics), climate and vegetation cover.
  • Second, a watershed accumulates some of the water that falls within its boundaries after it has infiltrated the soil. When the soils in the watershed are saturated, the water will either run off the soil surface or seep deeper in, where it then feeds freshwater aquifers. The type and amount of vegetation and the structure of plants can influence the storage capacity of a watershed. Greater plant-root mass, for instance, increases soil permeability, allowing moisture to percolate deeper into the soil where it’s stored.
  • Third, a watershed moves water through the soil to springs, then to streams, rivers, lakes and oceans. When it comes to water flow, slow is better than fast because speedy flows can cause rapid, heavy flooding. Heavy storms that make waterways rage can also result in flooding, soil erosion and sediment transport.

Following its “journey” through the watershed, water from precipitation returns to the atmosphere by evaporation, through a process called the water cycle (or hydrologic cycle). The water cycle, which works like a gigantic pump, is the constant movement of water within planet Earth and the atmosphere through processes or phases like evaporation, transportation, percolation, transpiration and, of course, precipitation (see Figure 1b). It has no beginning and no end.

For instance, the heat of the sun causes water to evaporate from the surface of vegetation, soil or bodies of water (rivers, lakes, oceans, etc.) and this water returns to the atmosphere in a gaseous state. The water vapour condenses on contact with cold air masses, resulting in the formation of clouds, which bring precipitation in the form of rain, snow or hail.

Through the Earth phase of the water cycle, all parcels of land within the watershed are connected. Therefore, all activities that take place in a watershed, as well as the physical, chemical and biological processes associated with them, are intertwined. Every action taken on the land at a given location either helps or hinders the watershed system. That’s why a watershed must be managed as an entity: each parcel of land plays an important role in the overall health of the watershed and, therefore, in the preservation of water resources.

Socioeconomic functions

Watersheds serve at least two ecological purposes (Black, 1997):

  • They create the channels and exchange mechanisms that ignite and fuel the chemical reactions that living organisms depend on to survive.
  • They provide a habitat for fauna and flora. The disruptions humans inflict on the physical, chemical and biological properties of water can harm fauna, flora and entire ecosystems. The impact imperils not only aquatic food chains, but also those of humans. Simple bottom line: watersheds are fragile settings that we need to preserve for our survival as a species.

Socioeconomic functions

Watersheds harbour life. No matter where you live, be it close to or far from a river, lake, stream or other body of water, you are part of a watershed. From time immemorial, watersheds have sustained life—human, animal and plant. A quick overview of history shows just how tightly intertwined the availability of water is with the socioeconomic development and stability of humans (Newson, 1988; Smith,1969).

This is especially true in Québec, where colonization revolved around waterways, and settlements like Québec, Montréal, Trois-Rivières and Gaspé took root along the St. Laurence River. Later, the early settlers moved up along the main tributaries of the St. Laurence River and founded what are today cities such as Sherbrooke, Saguenay and Gatineau, on the banks or at the juncture of the rivers there.

These hydrological resources not only shaped settlement patterns, but sparked Québec’s economic development, allowing the province to launch its textile, pulp-and-paper, electrochemical, aluminum and hydroelectric industries in the 19th and 20th centuries.

How municipal development affects water resources

Converting unspoiled land into commercial, industrial and residential properties strongly impacts water resources (Horwitz et al. 2008; White and Greer, 2006; Coles et al., 2004). For instance, development alters how water circulates throughout the watershed, both above ground and under; this also affects its quality.

As the watershed undergoes development, trees, bushes, shrubs and other plants give way to impermeable surfaces (roads, highways, roofs, sidewalks, parking lots and other compacted surfaces) that prevent stormwater from infiltrating the soil. For lack of plants to calm stormwater runoffs, less of this water enters the soil for storage and more of it rushes into rivers in a shorter time. The immediate effect is flooding; and in the longer term, there’s less stored water to replenish rivers during dry spells and to keep groundwater supplies plentiful. This not only impacts local waterways and sources (warmer water temperatures and lower water volumes), which rely on regular replenishment, but also harms the environment that aquatic organisms live in.

Higher volumes of runoff water erode shores and riverbeds, again harming the habitat of aquatic species, whose proper development depends on good-quality water. What’s more, sediment builds up at the bottom of channels, rivers, lakes and reservoirs, and this increases both the risk of flooding and the need to dredge waterways to ease navigation for pleasure craft and commercial boats.

In addition to larger runoff volumes caused by commercial, industrial and residential development, the water from that runoff brings more contaminants (heavy metals, pesticides, fertilizers, etc.) into local waterways after rainfalls or snowfalls.

Bottom line: any activity that changes the permeability, vegetation cover, as well as the quantity, quality and flow of water anywhere in a watershed can alter the features or characteristics of rivers lying downstream. And urban-development practices like deforestation, road building and home construction can come with devastating consequences even if they don’t take place near waterways.

That said, we do have ways to reduce the impact of development on aquatic settings. We can keep impermeable surfaces down to a minimum, maximize forest and vegetation cover, and build more stormwater runoff infrastructure like sediment catchment basins. Still, only a fully integrated, watershed-wide plan for urban development and land use can prevent activities or projects from wreaking environmental havoc downstream. Remember, a watershed’s own natural capacity to support such human activity is limited.

Integrated watershed management (IWM): definition and purpose

By using an integrated and coordinated approach to manage land and water within a watershed, we can sustain socioeconomic benefits associated with watersheds without endangering the survival of the vital ecosystems they harbour.

IWM came to be as we realized that water-related concerns revolve more and more around development practices and challenges that involve everything from health, socioeconomic, legal and political issues to concrete factors like mines, energy, transportation and agriculture, be it at the local, regional or provincial level (Biswas, 2004).

Many of these problems have become too complex, intertwined and disproportionate for a sole institution to tackle single-handedly, no matter how extensive its authority, how plentiful its technical expertise and resources, how robust its management capacity, how broad its level of political support, and how noble its intentions (Biswas, 2001).

Solving today’s water challenges requires the direct involvement of the entire community living in a watershed, including local, regional and provincial governments, industry representatives, businesspeople, forest and agriculture producers and members of the public.

The cornerstone of IWM is integration, which isn’t always clearly understood by those involved in water consumption and management. IWM combines or blends a range of relationships, like that between surface water and underground water, water quality and water quantity, water use and land use (environment), water consumption and stakeholder interests, as well as socioeconomic and political institutions (Mitchell, 1990a).

So, in the context of IWM, “integrate” can be seen as the establishment of links between multiple elements (land and water, for instance), the coordination of multiple elements to create a cohesive whole (coordinating the activities of different organizations, or coordinating policies and programs affecting water resources), the consideration of activities and interests of other institutions or groups in society (e.g. municipal activities and the concerns of government departments), and the pooling of activities, resources, knowledge, etc.

That said, integration isn’t a panacea that can resolve all the challenges surrounding water resources; what’s more, integration can be “partial,” so to speak, meaning that not everything needs to be integrated or blended (Cardwell et al., 2006; Curtis, 2004), and that’s because integration isn’t always necessary or even feasible. Finally, we can tap into a mix of laws, political commitments and administrative decisions to ensure integration (Mitchell, 1990b).

IWM is thus a collaborative, partnership-driven practice that prompts all water-resource stakeholders (government departments, municipalities, regional county municipalities, forest and agriculture producers, industry representatives and citizens in general) to mesh both the activities and the decisions that affect watersheds directly or indirectly. The IWM approach deals with all the issues that relate to or concern water resources: quality (chemical, physical and biological), quantity (both for surface water and underground water), biological diversity, habitats, fisheries, recreational activities, health, etc.

IWM benefits everyone, from taxpayers to those working in the public and private sectors. Taxpayers, for instance, win out when the water in lakes, rivers and other sources improves, because they can then partake without concern in whatever draws them to the water: swimming, skiing, windsurfing, sports fishing, or just relaxing on a beach and admiring the surroundings.

Public-sector stakeholders (municipalities, regional county municipalities, government departments, etc.) win out as well because, thanks to the cornerstones of IWM—cooperation and collaboration—public agencies can accomplish more than when acting alone with their limited resources. The trust and open-mindedness that blossom through teamwork allow those best acquainted with watershed-management challenges and possible solutions to play a more direct stewardship role.

The private sector also benefits in that the cost of protecting water resources—among other examples—can be shared fairly among parties whose activities or pursuits pollute at different levels.

Implementing the concept of integrated watershed management (IWM)

IWM is a very broad concept. Every country adapts it to the nature and severity of its water issues and to its internal circumstances (specific natural settings, human and financial resources, institutional capacity and responsibilities, strengths and weaknesses of water-resource stakeholders, political and cultural climate).

Québec opted to apply IWM gradually across its entire landmass. The province went from 33 priority watersheds covering nearly 20% of southern Québec in 2022 to a total of 40 IWM zones covering all southern Québec in 2009. An IWN zone usually involves multiple watersheds, and the responsibility for implementing IWM (activity coordination) in each of these zones belongs to a watershed organization (WO)—in French, organisme de bassin versant (OBV).

WOs are consultative bodies on which sit water-resource stakeholders (water users and managers in the area) and members of civil society. Thus, municipalities and each regional county municipality (RCM) are represented on a WO’s board of directors. Government representatives are also full members of WOs, but they don’t have voting rights. WOs ensure cooperation among all water-resource stakeholders locally and regionally.

WOs must not only craft water-management master plans (WMMPs) for their watersheds, but also consult the public on what goes into the plans, coordinate their implementation and provide follow-ups. The Cadre de référence pour les organismes de bassins versants prioritaires (Auger and Baudrand, 2004) specifies that WOs (unofficial translation) must NOT take over the role of local stakeholders […]. That means stakeholders holding legal water-management responsibilities (municipalities, RCMs, government departments) or those who are subject to provincial laws and regulations (forestry and agriculture producers, certain industries, etc.) are responsible for launching and conducting projects designed to correct most problems affecting their watersheds.

The government-recognized Agence de Bassin Versant des 7 (ABV des 7) is mandated with protecting and improving water quality in the seven watersheds found in its jurisdiction: Blanche Ouest, Coulonge, Dumoine, Gatineau, Noire, Quyon and part of the Outaouais (residual).

ABV des 7 designed a water-management master plan in 2014 for its entire jurisdiction, which includes the Blanche Ouest River. Of course, designing a preliminary WMP for such a large area as the ABV des 7 is a monumental task, so these initial versions will evolve into ever more detailed scenarios as the years go by.

The issues at stake also evolve as climate change progresses, urbanization spreads and recreation tourism brings more people into sensitive areas. Six years ago, increases in lakeside population and the proliferation of blue-green algae were top of mind; today, they remain a concern, but the matter is further complicated not only by the arrival of new invasive aquatic species, but also by the hydrological challenges stemming from extreme weather.

After this initial planning effort ended, the Fédération des lacs and the Municipalité de Val-des-Monts joined forces to craft a water-management plan focused on the Blanche Ouest watershed. The ultimate objective—without detracting from the colossal efforts of ABV des 7—is to assess the watershed at faster intervals and, so to speak, at a micro level.

Under the Québec environment ministry’s national water policy, every municipality and every RCM must put forward in its water-management plan specific actions to be included in it urban-development plans, policies and schemes. Not surprisingly then, water-management plans represent hugely important strategic documents in the application of integrated water management. Crafting these plans involves four stages:

  • Assessing the problems affecting water resources (algae proliferation in the summer, insufficient water supply, etc.)
  • Determining the issues at stake
  • Setting objectives
  • Designing a plan of action (list of problem-solving projects, how they’ll be implemented, who’ll cover the cost and when); water-management plans must shine for their technical and scientific quality, because the credibility of WOs in the eyes of municipal, government and socioeconomic stakeholders rests there, as does the legitimacy of the IWM process.

Elected municipal officials, watershed organizations and other water-resource stakeholders need to work closely together

Act to affirm the Collective Nature of Water Resources and Provide for Increased Water Resource Protection

Québec’s municipalities have multiple legal responsibilities—both direct and indirect—in water management. Among their direct responsibilities is ensuring the application of the Loi sur le captage des eaux et l’évacuation et le traitement des eaux usées (water catchment and wastewater disposal and treatment act).

The indirect responsibilities falling upon regional county municipalities (RCMs) involve protecting surface water from pollution, as specified in the Protection Policy for Lakeshores, Riverbanks, Littoral Zones and Floodplains, along with using land-use planning and development frameworks (LUPDFs) to regulate how land is occupied within their boundaries, as required by the Act Respecting Land Use Planning and Development.

Municipal authorities can include land-use rules and standards in LUPDFs that exceed the government’s occupation-density norms near waterways. Applied wisely and soundly, LUPDFs can influence the type and location of human activity in watersheds, making them powerful municipal tools in protecting and improving water levels and water quality there.

In addition, the general spirit of article 19 of the Loi sur les compétences municipales allows municipalities to adopt environmental regulations, for instance on the use of fertilizers on private properties.

Every RCM and each municipality can also work independently on minimizing the impact of urban development on its water resources, but without an integrated and collaborative approach, the capacity of watersheds to support human activity could be exceeded before we even realize it. This is already happening in several watersheds, as demonstrated by Gangbazo et al. (2004).

That said, municipal officials don’t have any authority over watersheds per se, only on the land within a watershed’s boundaries or land that straddles two or more watersheds. Compounding the problem is that lingering pollution from surface water, which directly affects the quality of the raw water destined for human consumption, can come from activity that’s beyond municipalities’ control.

Take the agriculture, forestry and industrial sectors, for instance, which are regulated by several ministries in Québec. With so many watershed authorities and stakeholders involved, it’s clear that the only way to manage this water resource sustainably is through strong collaboration among everyone concerned.


Protecting our water is a priority in the management of our natural resources; indeed, because of the many goods and services that they provide to their communities, watersheds represent an invaluable collective asset.

However, traditional approaches in this area have often favoured economic growth and development at the expense of protecting water quantity and quality. This way of doing things, with its hefty costs for society (Tegtmeier et Duffy, 2004), is starting to change, thankfully.

Integrated watershed management aims to coordinate all activities, policies and programs that impact water resources within a watershed. And given the powers granted to municipal authorities under the Act Respecting Land Use Planning and Development, these leaders are front and centre in the public control and administration of their municipality’s land.

So, by working with WOs, municipal officials can influence the type and the location of human activities within watersheds, thus reducing the risk of water pollution. And in the broader context, these efforts help provide residents with a clean and healthy environment in which to live.

Again, IWM isn’t about blocking economic development; rather, it’s about ensuring that development is planned in a way that doesn’t exceed a watershed’s capacity to provide residents with sufficient quantities of quality goods and services.

  • To cite this item, use the following reference: Gangbazo, G. (2009). Pourquoi les élus municipaux ont-ils intérêt à collaborer à la gestion intégrée de l’eau par bassin versant? Québec, ministère du Développement durable, de l’Environnement et des Parcs, Direction des politiques de l’eau, ISBN 978-2-550-56104-0, 10 pages.

Map of the Blanche Ouest River watershed