Wetland Evaluation System

The wetland evaluation system was created to inform Ontario’s land use planning process.

We provide manuals describing how wetlands are evaluated and offer annual training for professionals wishing to become qualified wetland evaluators.

Evaluation process

The wetland evaluation process defines, identifies and measures wetland functions and values.

Wetlands are assessed based on their perceived values in maintaining natural processes (ecosystem values). They are also assessed on the benefits provided to society (human utility values).

Ecosystem values

Ecosystem values include:

  • groundwater storage and release
  • provision of habitat for wildlife species
  • ecosystem productivity and biological diversity

Human utility values

Human utility values include:

  • flood damage prevention
  • harvestable product provision
  • improved water quality
  • recreational opportunities

The system ranks wetlands relative to one another.

Wetlands can only be evaluated by trained evaluators.

Trained evaluators can undertake wetland evaluations, re-evaluations or mapping updates by following the revised editions of OWES:

The wetland evaluator must do the following.

  • Attest that the wetland evaluation, re-evaluation or mapping update was completed in accordance with the new edition of the OWES manual (January 2023) by signing the wetland evaluation and scoring record.
  • Notify any affected landowners of the property or properties containing the wetland of the final wetland boundary and wetland status.
  • Send the final evaluation, including associated wetland boundary mapping to the appropriate planning authority (such as a municipality). For areas outside of municipal boundaries, please see the applicable OWES manual (Northern or Southern) to determine where to send the evaluation. In areas of the province without municipal organization, forward the final evaluation to the ministry for record keeping purposes.
  • Submit the final digital wetland boundary mapping and the wetland’s status (such as significant) within 30 days of completing an evaluation to the ministry at wetlands@ontario.ca.
  • Submit wetland boundary mapping in shapefile format completed in a standard consistent with the wetland data class in the Land Information Ontario (LIO) warehouse and produced using GIS systems. A shapefile should be submitted with all required fields including the wetland’s status (i.e. "evaluated-other" or "evaluated-provincial").

Manuals and guides

These manuals are technical guidance documents that use scientific criteria to quantify wetland values and allow comparisons among wetlands.

The manuals provide the “evaluation procedures” referred to in the Provincial Policy Statement. They are used to determine wetland significance under Section 2.1 of that document. Great Lakes coastal wetlands are evaluated using these manuals.

There are 2 evaluation manuals, each used for different regions:

  • Southern Ontario Wetland Evaluation System manual is used for all wetlands located in Ecoregions 6 and 7.
  • Northern Ontario Wetland Evaluation System manual is used for all wetlands located in Ecoregions 2, 3, 4 and 5.

Ontario Wetland Evaluation System Southern Manual (PDF)

Ontario Wetland Evaluation System Northern Manual (PDF)

Ontario Wetland Evaluation System Manuals Executive Summary

Find a wetland evaluator

To find a qualified wetland evaluator that successfully completed the Ontario Wetland Evaluation System Course:

  1. Conduct your own web search for consulting companies that do wetland evaluations or
  2. Please visit the Wetland Evaluators List. These evaluators have agreed to share their contact information through this website.

Become qualified to evaluate wetlands

To become a qualified wetland evaluator in Ontario, you must:
  1. Take an Ontario Wetland Evaluation System (OWES) course.
  2. Pass an exam.

We deliver the courses or authorize someone else to teach you.

Who can take the course

This course is required if you conduct wetland evaluations (for example, conservation authorities, municipalities, wetlands consultants, environmental groups, Ontario Public Service).

While the course is open to anyone, due its technical nature, it’s best if you have specialized skills and understand technical information about:

  • wetland ecology
  • wetland functions
  • plant identification
  • the use of field guides and keys
  • geographic information systems

The course is only available in English.

What the course covers

The course covers:

  • how to evaluate wetlands and determine their provincial significance
  • the southern and northern manual

How to register

There’s a waiting list to register for the OWES course.

To get on the waiting list:

  1. Log in or create an account on the Learning Compass website.
  2. Select “Wetland Courses”.
  3. Select “OWES Certificate Course”.

Courses are filled on a first-come, first-served basis. You’ll get an email when there’s a spot available for you.

If you have any questions about registration, fees or upcoming courses, please see the Nipissing University webpage, or contact:

Dr. Jeff Dech
Nipissing University
Email: jeffreyd@nipissingu.ca

For more information

For digital mapping information, visit Land Information Ontario’s GeoHub and search for the “Wetland” data class, or navigate to Ontario’s Make a Natural Heritage Map web application.