Citation

  • Eyquem, J. (2023). Managing Flooding and Erosion at the Watershed Scale: Guidance to Support Governments Using Nature-Based Solutions. Canadian Standards Association, Toronto, ON.

Executive Summary

Flooding and erosion are natural river processes that have been, and continue to be, modified by human activity. Risks result where flooding and erosion present a danger to public safety and built infrastructure.

Historically, flood and erosion risk management techniques have relied largely on “grey” infrastructure solutions, such as flood walls, dikes, and river channel modifications, to control natural processes and reduce risk. Many of these techniques resulted in negative impacts on river ecosystems.

In contrast, nature-based solutions (NbS), such as restoring wetlands or upland forests, can be used to manage river flooding and erosion in a way that provides benefits for both people and nature. This role is specifically identified in Target 11 of the recently adopted Kunming-Montreal Global Framework Directive, which calls for parties to use NbS to restore, maintain, and enhance nature’s contributions to people, including protection from natural hazards.

The role of NbS in flood and erosion risk management is increasingly recognized in Canada but it is not yet mainstream. Key needs identified in recent international and national publications include:

  • Adoption of a “whole-ecosystem” approach to flood and erosion management at the watershed-scale.
  • Identification and valuation of the multiple co-benefits of NbS; and
  • Proactive management of natural infrastructure alongside built infrastructure, including preserving, conserving, and restoring natural assets.

The paper puts forward three recommendations to support future implementation of NbS for flood and erosion risk management by governments in Canada, supported by findings of this research report:

1. Development of a consistent approach to integrated watershed management.1.

A review of watershed management in southern Canadian provinces, where the majority of Canadians live, found that Ontario is the only province where watershed-scale organizations (called Conservation Authorities) have a legal mandate that combines river flood and erosion risk management (with exceptions) and nature conservation. While many provinces have developed programs to support NbS, the objectives of these programs frequently focus on habitat quality and biodiversity rather than flood and erosion risk objectives. There is opportunity to build on the existing good practice approaches identified in this report and extend them to other provinces.

2. Allocation of funding to watershed-scale flood and erosion strategies that address high-risk areas.

Analysis indicates that many flood and erosion risk management projects funded under the federal National Disaster Mitigation Program (NDMP) and Disaster Mitigation and Adaptation Fund (DMAF) have been led by, and undertaken within, single cities and towns. Watershed-scale organizations have only undertaken funded projects in Ontario and British Columbia. In addition, only a few projects funded under the NDMP and DMAF programs have incorporated NbS. Future funding of watershed-scale strategies should support measures, such as NbS, that address underlying causes of flood and erosion risk, while achieving multiple benefits. Indigenous governments could play a leading role in such watershed-scale approaches.

3. Routine consideration of NbS for river flood and erosion management.

NbS are currently an underutilized option for flood and erosion risk management in Canada. There is an opportunity to update protocols or funding procedures to promote consideration of NbS as the default solution, with grey solutions being compared and applied where technically required or more beneficial overall.

Federal, provincial, watershed-scale, and local governments (including municipal and Indigenous governments) all have key roles to play in implementing the above stated recommendations:

Federal government

  • Support and work with provincial governments to develop guidance for, and help fund, a nationally consistent watershed planning framework that includes agreed-upon minimum requirements for flood and erosion risk management at the watershed scale. This could be progressed through the Canadian Water Agency or through work to achieve targets set by the National Adaptation Strategy (although the strategy itself does not explicitly include watershed-scale management, several of the objectives and targets would benefit from this approach).
  • Work with provincial governments to identify priority watersheds (high-risk areas or vulnerable communities) for which flood and erosion management strategies are required to be completed first (if they have not been completed already).
  • Update existing federal funding programs (e.g., DMAF, Natural Infrastructure Fund) or create new funding programs to a) direct funds to projects that address flood and erosion risk at the sub-watershed / watershed-scale and b) require routine consideration of NbS as the default solution, to be combined with grey infrastructure where necessary.
  • Support development and use of national guidelines and standards to support use of NbS for flood and erosion management (see Section 5.3 for discussion of specific standards).

Provincial governments

  • Strengthen provincial legislation and policy to support watershed-scale approaches to manage flood and erosion risk, including the use of NbS.
  • Work with the federal government to develop guidance for, and help fund, a nationally consistent watershed planning framework that includes agreed-upon minimum requirements for flood and erosion risk management at the watershed scale. Provincial governments have a key role to play as watershed management (apart from international watersheds) is a provincial jurisdiction.
  • Work with federal government to identify priority watersheds (high-risk areas or vulnerable communities) for which flood and erosion management strategies are required to be completed first (if they have not been completed already).
  • Develop flood and erosion risk management strategies at the watershed / sub-watershed scale for prioritized high-risk areas. Update provincial funding programs to a) direct funds to projects that address flood and erosion risk at the sub-watershed / watershed-scale and b) require routine consideration of NbS as the default solution, to be combined with grey infrastructure where necessary.

Watershed governance organizations

  • Work to include the use of NbS for flood and erosion risk management as a watershed management objective. Ensure that the flood and erosion risk reduction benefits of NbS are documented, even when this is not the primary objective of the solution.
  • Continue to use NbS for flood and erosion management as a default solution where appropriate. Work with local community groups, businesses, and governments to publicize the multiple benefits delivered.
  • Work to inventory, value, and manage the services provided by natural assets within the watershed, including flood and erosion protection. Continue to protect existing natural assets and prioritize restoration efforts in areas with the highest potential benefit.
  • Continue to provide technical support to local governments with flood and erosion risk management and planning / implementation of NbS projects.
  • Communicate the value of natural assets and the role of NbS in flood and erosion protection to residents.

Local governments (including municipal and Indigenous governments)

  • Work with watershed organizations to help identify, plan, and implement NbS for flood and erosion risk management.
  • In the absence of a watershed governance organization, work with other local governments to help identify, plan, and implement NbS for strategic flood and erosion risk management at a watershed / sub-watershed scale.
  • Consider NbS as the default solution for flood and erosion risk management, to be combined with grey infrastructure where necessary.
  • Work to inventory and value the services provided by natural assets, within both the local government jurisdiction and upstream watershed, including flood and erosion protection.
  • Communicate the value of natural assets and the role of NbS in flood and erosion protection to residents.

Future standards that could support implementation of the three recommendations are:

  • A minimum framework for watershed management planning;
  • A standardized approach to the strategic appraisal of river flood and erosion risk management options at the watershed-scale;
  • Standards to support the identification, valuation, and management of services provided by natural assets; and
  • A standardized option appraisal protocol for flood and erosion management projects, integrating the financial value of benefits and costs associated with NbS.