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Wetland Offsetting Policies in Ontario

Demonstrating key strengths and opportunities for improvement

Wetland in the GTA

Case Studies

Even though the Government of Ontario has not yet produced a provincial standard on wetland offsetting, local authorities are turning to this practice to compensate for the increasing pressure of development on remaining wetlands.

Many conservation authorities and municipalities have embedded provisions for wetland and other ecosystem offsetting within their permitting policies, with a handful endeavoring to develop fully-fledged offsetting policy documents.

Rosedale Park, Whitby © Christine Ambre

High Standards Set by Conservation Authorities

To date, four of Ontario’s conservation authorities (CAs) have produced detailed ecosystem offsetting policies with the goal of guiding the effective and consistent application of offsetting practices in their jurisdiction.

These four CAs are:

  • Toronto and Region Conservation Authority,
  • Credit Valley Conservation,
  • Lake Simcoe Region Conservation Authority, and
  • Nottawasaga Valley Conservation Authority.

You can find some examples of high standards for wetland and other ecosystem offsetting below.

Rattray Marsh Conservation Area, Mississauga © Kevin Cabral CC BY 2.0

Toronto and Region Conservation Authority (TRCA)

Guideline for Determining Ecosystem Compensation (2018)

  • Section 1.4 requires strict adherence to mitigation sequence, stating that offsetting must only be considered “as a last resort within the established mitigation hierarchy of: Avoid, Minimize, Mitigate, Compensate.” A “protection first” approach is emphasized throughout.
  • Section 3.2 states that offset site selection must consider proximity to loss, continuity with the natural system, land ownership and designation (with a preference for publicly owned land with environmental protection zoning), land availability and ecosystem connectivity and configuration. Offsets implemented by parties other than TRCA must document the rationale for their site selection, and it must be approved by TRCA. TRCA-led offsets are to be located using their “Restoration Opportunities Database” and other site selection tools.
Glen Haffy Conservation Area © Florin Chelaru CC BY 2.0

Credit Valley Conservation (CVC)

Ecosystem Offsetting Guidelines (2020)

  • Section 1.8 prioritizes net gain in ecosystem value as the policy goal, stating that offsetting “should target an ecological (net) gain.” When net gain is determined unfeasible, the goal is to “ensure no-net-loss.”
  • Section 1.8 requires strict adherence to the mitigation sequence: “Offsetting should only be applied after a detailed analysis has determined that avoidance, minimization and mitigation of loss is not possible or feasible.”
  • Per Section 3.1, offset site selection must consider proximity to the loss, land availability, land ownership and designation (with a preference for publicly owned land with environmental protection zoning) and potential viable ecosystem types based on site characteristics. CVC provides tools to guide this decision, including the Restoration Opportunities Database.
Rattray Marsh Conservation Area © Margaret Bourne CC BY-NC-ND 2.0

CVC Continued

  • Clear metrics and methods of quantifying losses and gains are provided throughout the policy, including detailed direction on collecting baseline data in Section 2.1, determining replacement ratios that vary by ecosystem type and component in Section 2.3 and considerations for landscape level impacts in Table 7.
  • Section 3.1.17 indicates that offsets must be monitored for a minimum of 5 years (or longer, for ecosystems with longer establishment times). Results must be reported to the authority and, if the offset is failing, the appropriate adjustments must be made.
Credit River wetlands © Jarrett CC BY-NC-ND 2.0

Lake Simcoe Region Conservation Authority (LSRCA)

Ecological Offsetting Policy (2021)

  • The policy makes a strong commitment to ensuring net gain, reflected in Section 3.3 which requires ecological offsetting strategies to demonstrate that the proposed offset “will result in a “net gain” of natural heritage features” and in requiring that offsetting for both wetlands (Section 3.3.1) and woodlands (Section 3.3.2) exceed the size of the ecosystem being impacted.
  • Section 1.8 requires strict adherence to the mitigation sequence: “Offsetting should only be applied after a detailed analysis has determined that avoidance, minimization and mitigation of loss is not possible or feasible.” Section 3.2 also requires strict adherence to the mitigation sequence as a prerequisite to approving offsetting. It must be demonstrated that “the mitigation hierarchy steps of avoiding, minimizing and mitigating have been followed and that compensation is the only viable option.”
Great blue heron rookery © Christa R CC BY-NC 2.0

LSRCA Continued

  • Section 3.1 explicitly recognizes that there are limits to offsetting and states that offsetting will not be considered features containing rare vegetation communities, bogs or fens, watercourses or the minimum vegetation protection zone abutting the Lake Simcoe shoreline.
  • Under Section 3.3, offsets must be located in the same subwatershed as the impacted feature (preferably on property owned or which may be transferred to a public agency) and expand or enhance the defined natural heritage system.
Beaver River, Uxbridge © Sean Marshall CC BY-NC 2.0

Nottawasaga Valley Conservation Authority (NVCA)

Achieving Net Gains through Ecological Offsetting (2021)

  • The policy implies a goal of achieving net gains through offsetting, as referenced in the title and the Section 3.3 requirement for development proponents to replace twice as much wetland area as is impacted.
  • Section 3.1 outlines requirements to adhere to the mitigation sequence, stating that “Avoidance of impacts is the first priority for any development proposal, followed by all reasonable efforts to minimize impacts.” Rationale must also be provided to justify any inability to avoid or minimize impacts and must go beyond project efficiency or practicality.
  • Section 2.2 recognizes that there are limits to offsetting and that the policy will not permit offsetting for significant features as defined under the Provincial Policy Statement.
Trumpeter swan, green-winged teal, tree swallow, Minesing Wetlands © Noah Cole

NVCA Continued

  • Section 4.1.1 details the offset site selection process, which must consider land ownership (with a preference for public ownership), geographic location (with a preference for sites in proximity to the impacted site), site suitability to support the desired ecosystem type and its ability to replace core ecosystem functions. NVCA also identifies priority restoration areas in their Fisheries Habitat Management Plan.
  • Section 4.1.3 indicates that offset monitoring and maintenance must be conducted annually for at least five years or until “the created feature has demonstrably reached a functional equilibrium” and results are to be reported to NVCA. Replanting must be conducted if initial plantings have a survival rate under 70% two years after establishment.
Minesing Wetlands © Joe Mabel

Opportunities for Improvement

Each of these policies has strengths, consistently including a strict requirement to adhere to the mitigation sequence and ensuring strategic site selection for offset projects. However, they also share some common shortfalls:

  • No policy explicitly considers social and cultural ecosystem values under the scope of policy goals.
  • No policy makes a commitment to ensure meaningful and respectful engagement with Indigenous communities.
  • Public infrastructure projects are often exempted from adhering to the strictest requirements of the policies.
  • While transparency and accountability are supported through detailed mandatory reporting to the conservation authority, little to no detailed information about the status of offsetting projects is made available to the public.
Mitchell's Bay wetland, Chatham-Kent © Sue Thompson CC BY-ND 2.0

By addressing these key opportunities for improvement, Ontario’s conservation authorities can continue to demonstrate their leadership in wetland offsetting policy.