Assessment of the tributary streams of Lake Saint-Pierre in order to improve water quality and wildlife habitats

The small tributary streams of Lake Saint-Pierre are facing several problems which are contributing to the degradation of the lake’s water quality and habitats. The main issues are missing or poor-quality buffer strips, streambank erosion, sedimentation and nutrient inputs carried by the tributaries.

A study-action project, funded by the Community Interaction Program of the St. Lawrence Action Plan, was carried out in order to gain a better understanding of the problems affecting the tributary streams of the two regional county municipalities (RCMs) bordering Lake Saint-Pierre. The “study” component involved conducting a characterization exercise of the priority streams in order to describe the nature of the problems and devise intervention plans. Subsequently, the “action” component involved carrying out restoration work on two tributaries identified as priorities for improving the water quality and wildlife habitats of Lake Saint-Pierre.


During the first part of this project, 68 small streams flowing into Lake Saint-Pierre were characterized. For each, a biophysical assessment of the sites was conducted to identify the factors contributing to the degradation of water quality and wildlife habitats. The main problems observed were:

  • Inadequate or non-existent buffer strips;
  • Poorly vegetated and unstable streambanks in agricultural areas;
  • Culverts that were damaged, inadequate, silted-up or lacking altogether; and
  • Vegetation creating obstacles to the free movement of water and fish.

Based on the data collected, an intervention priority code was assigned to each tributary. Each RCM concerned then received an intervention plan outlining the actions recommended to improve the state of their streams. These plans were also submitted to the Quebec Department of Forests, Wildlife and Parks and the Quebec Department of Sustainable Development, Environment and the Fight against Climate Change.


The last phase of the project involved implementation of the recommendations aimed at restoring the Lavigne Stream of the D’Autray RCM and the stream in segment 7 of the Nicolet-Yamaska RCM. The following are a few figures which illustrate the restoration work carried out for these two streams.

Lavigne Stream, D’Autray RCM

The project involved carrying out restoration and enhancement work affecting an area of 67,772 m2 of the stream and its buffer strip, i.e.:

  • Restoration of a total length of 4,897 m in the main stream and its branches
  • Establishment of 3- to 5-m-wide buffer strips
  • Agreements in perpetuity for buffer strip conservation signed with 17 property
  • Replacement of 23 culverts
  • Planting of more than 15,000 shrubs

Stream in segment 7, Nicolet-Yamaska RCM

The project involved carrying out restoration and enhancement work affecting an area of 32,051 m2 of the stream by creating buffer strips and a forest corridor, i.e.:

  • Restoration of a total length of 1,144 m
  • Establishment of 4-m-wide buffer strips
  • Replacement of eight culverts
  • Planting of 10,000 shrubs

Buffer strip prior to restoration

Buffer strip after restoration

Photos: @ Comité ZIP du lac Saint-Pierre

Restoration and enhancement of the mouth of the Brochu River

The mouth of the Brochu River is an exceptional natural environment of the North Shore region. Sheltered by a sandy spit that runs parallel to the shore, there is a small bay that includes a 17 ha salt marsh. The mixing of freshwater from the St. Lawrence River and saltwater from the Gulf of St. Lawrence creates a unique environment that is home to a variety of wildlife species.

However, this exceptional site is subject to various natural and anthropogenic pressures. For example, there are problems of natural erosion, as well as problems of habitat loss and degradation of the spit caused by the frequent passage of off-road vehicles (ORV).

In order to protect this fragile environment, between 2013 and 2016, the Gulf North Shore ZIP (area of prime concern) Committee carried out a project to restore and enhance the mouth of the Brochu River and its salt marsh. The activities undertaken during the two phases of the project included building observation structures, developing public awareness-raising tools as well as restoration of approximately 10,000 m2 of the spit by planting nearly 70,000 sand ryegrass plants. This revegetation has had a number of positive impacts, such as improving the habitat of several species, including the nesting sites of the Common Tern.

You can learn more about the various components of this project, supported by the Community Interaction Program of the St. Lawrence Action Plan, by consulting the guide on the salt marsh of the Brochu River produced by the Gulf North Shore ZIP Committee (available in French only).


Photo : © Gulf North Shore ZIP Committee

Restoration of natural areas in the Matane region

Since 2002, the environmental group Uni-Vert has been restoring several natural sites located at the cliffs along the shore of the St. Lawrence River in the Matane region. This group's interventions have helped preserve local biodiversity by restoring existing habitats, by preventing eroded material from filling habitats located at the foot of the cliffs, and by stabilizing the coastal environment.

To control the erosion process in the cliffs and to prevent them from collapsing, Uni-Vert is continuing its efforts to restore habitats in Petit-Matane by installing brush mats and wattle fences. The photos below show the growth of the new vegetation that was planted for this purpose in spring 2014.

Shore cliff prior to restoration (May 2014)

Vue de la falaise avant restauration

Photo : © Sud-de-l’Estuaire ZIP Committee, Étienne Bachand, 2014

Shore cliff after restoration (September 2014)

Vue de la falaise après restauration

Photo : © Environment Canada, Catherine Soumagnas, 2014

Intervention plan for the Réserve naturelle des Battures-de-Saint-Augustin-de-Desmaures

The Réserve naturelle des Battures-de-Saint-Augustin-de-Desmaures is located on the shores of the St. Lawrence River near an urban area and farmland. To ensure the preservation of this important natural environment, the Fondation québécoise pour la protection du patrimoine naturel (FQPPN), together with the Corporation du bassin de la Jacques-Cartier, characterized the 12 watercourses that run through the Reserve, creating an inventory and mapping the problems, such as erosion, shoreline degradation, invasive plant species or water pollution, that affect the watercourses.

Following the characterization, the FQPPN created an intervention plan that includes specific action to remedy the problems. The intervention plan also targets potential stakeholders, enabling us to rally local stakeholders around common issues and make them aware of the importance of preserving these watercourses and, by extension, the St. Lawrence.

This project, which allowed for a useful diagnosis, is a great example of co-operation between the FQPPN and the Corporation du bassin de la Jacques-Cartier. The participants are now ready to take action and are already co-operating to this end with the municipality of Saint-Augustin-de-Desmaures. This project is all the more important given the rapid development of the Quebec City metropolitan region.

The intervention plan can be consulted on the FQPPN’s website at under the Publications heading.

Water course on the reserve

Photo : © Corporation du bassin de la Jacques-Cartier, 2014