Updated Ontario Wetland Evaluation System (OWES) Manuals

Regulation Number(s):
Instrument Type:
Bill or Act:
Summary of Decision:
A decision was made on March 20, 2013 to proceed with the proposal.

Links to the final documents are provided:
-Ontario Wetland Evaluation System - Southern Manual (13 MB)

-Ontario Wetland Evaluation System - Northern Manual (12.9 MB)

Further Information:
Proposal Number:
Posting Date:
January 25, 2012
Summary of Proposal:
The Ontario Wetland Evaluation System (OWES) is a science-based ranking system that provides a standardized approach to determining the relative value of wetlands. High value wetlands are considered to be provincially significant and commonly are referred to as "provincially significant wetlands" (PSW). The OWES consists of the ministry's technical manuals that are used to evaluate the significance of wetlands, for land use planning purposes. The OWES manuals are the "evaluation procedures" referred to in Ontario's Provincial Policy Statement (PPS), issued under the authority of the Planning Act.

The PPS provides policy direction on matters of provincial interest related to land use planning. It sets out policies for the protection of significant wetlands and defines significant wetland to mean an area identified by the Ministry of Natural Resources as provincially significant based on the OWES.

There are two OWES manuals, one for southern Ontario and one for northern Ontario.

The manuals are reviewed periodically to incorporate new science, technology and information. The OWES was created in 1982 and revised in 1984, 1994 and 2002. The Ministry of Natural Resources is updating both manuals.

The update to the OWES manuals is scoped in nature, i.e., not all components of the system are being reviewed. The basic structure and scoring components of the OWES remain the same. Key proposed revisions include :

- Updated references to current legislation and policies

- Improvements/updates to identification and scoring criteria
Delineation of wetlands and wetland boundaries, use of mapping standards
Species at risk, wetland rarity, flood attenuation and recreational activities

-Updated definitions
Great Lakes coastal wetland

- Administrative changes
instructions for file updates, and documentation of wetland features not scored in evaluations;
correct errors and inconsistencies

Commentator Instructions: In reviewing the draft 2012 update of the manual commentators are asked to focus their responses on above-noted revisions to the manuals. To access the draft revised OWES manuals please use the web link, below.
Contact Address:
Effective Date:
April 3, 2013