Erosion and Sedimentation Management for Northern Community Infrastructure (CSA W205:19)

In 2019, the Canadian Standards Association (CSA) Group published a new standard on erosion and sedimentation management for northern community infrastructure (CSA W205:19). Funding for the development of the Standard came from the Standards Council of Canada (SCC), as part of the Northern Infrastructure Standardization Initiative (NISI) with input from the Northern Advisory Committee (NAC).

Climate change is accelerating erosion and sedimentation in Canada’s North. Though all regions of Canada are experiencing environmental impacts that can be attributed to climate change, warming in Canada’s North is taking place at a faster rate than the rest of Canada and more rapidly than many climate models predicted.

While there are numerous guidelines available to help decision-makers in the preparation of suitable erosion and sedimentation risk management strategies and mitigation plans, no unified standard has yet been prepared specifically to address the issues in Canada’s North.

This new Standard draws on industry expertise and best practices in Canada and internationally to address requirements for managing erosion and sedimentation risks in coastal and lakeshore environments, open-channel environments, and terrestrial environments. This Standard applies to the management of erosion and sedimentation risks, including the evaluation, planning, design, implementation, monitoring, and maintenance of erosion and sedimentation risk management strategies and mitigation measures for new and existing infrastructure in Canada’s northern communities.

Understanding and Assessing Impacts

The Standard outlines a risk assessment process to be applied to infrastructure to mitigate the environmental damage, destruction and health risks as a result of drivers of increased erosion and sedimentation including climate change. Assessing risk associated with northern infrastructure shall consist of the following components:

  1. identifying the main characteristics of the infrastructure to be taken into account in the risk assessment process;
  2. identifying hazards;
  3. assessing the probabilities of occurrence of each hazard by analyzing available traditional knowledge, historical data, and results of predictive models; and
  4. assessing the consequences of the damage to the infrastructure, the local community, and the environment.

The present and ongoing impact of climate change are considered through each of the risk assessment components. The Standard draws from a wide range of climate research and data from academic and provincial and federal government agency assessments.

Climate change is accelerating erosion and sedimentation in Canada’s North. Though all regions of Canada are experiencing climate change impacts, all climate change models have thus far indicated that climate change will be greater in the Arctic than in other regions of Canada, with current warming in the Arctic at more than twice the rate of global mean temperatures, and this discrepancy is expected to become more pronounced over time. Moreover, the rate and amount of future warming is strongly dependent on ongoing and future GHG emission scenarios (e.g., RCP 4.5 vs RCP 8.5).

The main climate hazards that can impact northern infrastructure vary according to geographical region and environmental settings. The primary climate drivers of erosion and sedimentation considered in a risk assessment analysis include, but are not limited to:

  • sea level;
  • wave climate and extremes;
  • the frequency and intensity of storm events;
  • hydrology;
  • sea or lake ice cover and dynamics; and
  • permafrost thaw

Identifying Actions

The Standard that was written especially for northern communities and is meant to better manage erosion and sedimentation by avoiding practices that make erosion and sedimentation worse, while also helping northern communities adapt to climate change. The Standard was a developed through a collaboratively process that included northern business leader and infrastructure experts who provided local knowledge and expertise.

This Standard is organized according to the progression of actions that should be undertaken to address the risks associated with erosion and sedimentation to existing or new buildings, structures, utilities, transportation networks, coastal, lakeshore, and riverine facilities, and other built infrastructure. Considerations include the effects of infrastructure, and the associated potential for erosion, sedimentation, and the mitigation thereof, to impact the natural environment.

Key guidance includes:

  1. Procedures for conducting an overall risk assessment, including infrastructure vulnerability;
  2. Factors related to erosion and sedimentation to be considered in land use and infrastructure planning;
  3. An overview of drivers of erosion and sedimentation hazards
  4. Procedures to be applied and erosion protection measures to be considered in three primary environments:
    1.  coastal and lakeshore;
    2. open channel; and
    3. terrestrial.
  5. Specific steps taken to evaluate and address erosion and sedimentation risks, including:
    1.  site-specific evaluation and risk assessment;
    2. planning and design; and
    3. structural measures.
  6. Best practices for managing erosion and sedimentation;
  7. Procedures for inspecting, monitoring, and maintaining erosion and sedimentation mitigation measures;
  8. Guidance on incorporating adaptive management;
  9. Roles and responsibilities of personnel organizing or supervising the installation, inspection, monitoring, and maintenance of erosion and sedimentation mitigations;
  10. Emergency response and contingency planning protocols
  11. A framework for community-based processes for addressing erosion and sedimentation, and impacts to infrastructure

Implementation

The implementation requirements provided in this Standard are intended to address erosion and sedimentation risks to:

  1. existing or newly proposed community infrastructure, which might be exposed to erosion and sedimentation hazards under present-day or future conditions; and
  2. the environment, as a result of infrastructure projects that cause disturbances to soil, including excavations, vegetation/topsoil removal and grading, and development-related activities that could impact an environmental feature including a coastal or inland shoreline, watercourse, wetland, forest, etc.

This Standard also applies where erosion and sedimentation risk management measures are required by contract, permit, regulation, or other approval. The application of the Standard begins with the overall risk assessment and evaluation of infrastructure vulnerability phases of a project. The application of the Standard continues throughout the lifespan of the infrastructure project or strategic planning cycles, including site preparation, construction, operation and maintenance, and decommissioning, or until residual risk levels are deemed acceptable.

Types of infrastructure
This Standard applies to the evaluation, planning and design, implementation, as well as monitoring and maintenance of erosion and sedimentation mitigation measures during all phases of construction, service life and decommissioning of:

  1. buildings or additions to buildings (subdivisions or individual buildings including housing, commercial or community centres, offices, schools, etc.);
  2. infrastructure (roads, bridges, culverts, dams, hydraulic structures, utilities, sewers and watermains, landfills, sewage treatment facilities, piers, wharfs, breakwaters, shore protection, bank/slope stabilization, etc.);
  3. natural resources extraction infrastructure and operations (e.g., mining, drilling);
  4. farming infrastructure and operations; and
  5. expansions of any of these types of facilities or structures.

Intended Users
This Standard identifies a number of intended users including (but not limited to): infrastructure owners and operators; contract administrators; site investigators; design professionals, consulting engineers, architects, and territorial or regional technical services staff who design, assess and approve, and oversee the implementation of engineering-based interventions; contractors who implement engineering-based interventions; regulatory authorities; compliance authorities; land use planners and community planning officials, and; educators

Outcomes and Monitoring Progress

The Standard provides guidance on ongoing inspection, monitoring, and subsequent maintenance of erosion and sedimentation control (ESC) measures associated with new and existing infrastructure projects. These actions should occur continuously throughout the life of the project in order to identify potential problems and facilitate corrective action.

Inspection and monitoring activities shall be outlined in a plan that details the required tasks and task frequency associated with:

  1. ESC measure inspections;
  2. ESC measure monitoring;
  3. environmental inspections;
  4. environmental monitoring;
  5. documentation and communication; and
  6. selecting a maintenance response.

Resources

Link to Full Case Study

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