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 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.