Integration of Future Climate Scenarios in the Planning of Wetland Conservation and Restoration to Protect the Water Resources of Québec City

The effects of climate change are becoming increasingly significant, especially in cities where urban sprawl is causing major conflicts over water use. In this regard, wetlands are green infrastructure that regulate watercourses by reducing flood flows and increasing flow during low-flow periods.

It seems obvious, therefore, that improving our ability to model the role of wetlands in mitigating the effects of climate change will make it possible to ensure more sustainable management of water resources.

This project proposes to study the issues, challenges and opportunities arising from a better understanding and management of wetlands in the territory of Québec City.

• Support the development of regional wetlands and bodies of water plans (PRMHH) by documenting the role of wetlands in protecting Québec City’s water resources;

• Assess the role of wetlands in regulating floods and low flows under different climate and land use projections;

• Assess wetland restoration needs throughout the territory;

• Characterize the social representations of protective measures dedicated to the conservation objectives of PRMHHs in order to facilitate the application of the Act respecting the conservation of wetlands and bodies of water.

• Assess wetland and water body restoration needs for the entire territory using maps and other tools;

• Design a restoration plan for Ruisseau Savard and the peat bog at the Base de plein-air de Sainte-Foy;

• Recommend conservation and restoration thresholds to be considered in PRMHHs based on thresholds established in other jurisdictions;

• Assess the social representations of protective measures dedicated to the conservation objectives of PRMHHs;

• Develop conservation networks that optimize the provision of ecological services in areas where the demand for these services is greatest.

The aim of this project was to assess the role of wetlands in the regulation of high and low water levels under different climate and land-use projections.

The restoration needs of wetlands and water bodies were assessed in the area studied by using methods such as mapping the floodplains in terms of flow rates, estimating the quantity of wetlands that must be restored in order to mitigate the effect of climate change, and directly surveying the needs of local residents and experts in order to identify priority sites for restoration. Our analysis shows that the quantity of wetlands to be restored varies greatly between watersheds, particularly with regard to flooding.

Two pilot projects enabled recommendations to be made for specific restoration plans:

• For the Base de Plein Air de Sainte-Foy, the open peat bog was identified as the conservation priority due to its uniqueness, its abundance of native wetland species and the absence of exotic species. 

• In the case of Savard Creek, we identified a topographical and vegetation scenario that would allow for continuous flow, limiting water surges. The existing stormwater pipe could be used to evacuate excess water during exceptional flooding, which would be less than 10% of the time, according to the modelling.

However, a comparative analysis of different jurisdictions showed that setting conservation targets is rarely based on a scientific evaluation, but rather negotiated on the basis of international objectives. The analysis also stresses the importance of involving stakeholders right from the identification of sites to be included in a conservation network, and of having these sites assessed by an independent institution and/or supervisory body.

Lastly, the social aspect was examined by analyzing the content of official documents related to wetland and water body protection. We noted a lack of steps to assess the compatibility of land use planning and development plans (and interim control bylaws) with regional wetland and water body plans. Furthermore, entrusting this assessment to the regional municipalities, who are both stakeholders and decision-makers, seems to make uniform, consistent assessment of the plans problematic. For effective action, the concept of avoidance must be reinforced and knowledge of wetland restoration and creation improved.

Figure 1: Parcels of land studied in terms of recreational trails, drainage channels and wetland delineation.

Figure 2: Identification of conservation and restoration needs - Uniqueness values (LCBD - Local Contribution to Beta Diversity) vs. mean coefficient of conservatism (C-value; tolerance to disturbance) for all parcels (n = 70). Parcel numbers are indicated on the circles. Parcels with significant uniqueness are identified by asterisks (significance codes: p ≤ 0.05*, p ≤ 0.01**).
 

This project is funded by the Government of Quebec and meets the objectives of the Plan d'action 2013-2020.

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