Flooded With Change: Ontario’s New Proposals For Provincial Watershed Management

The Ministry of Environment, Conservation and Parks (“MECP”), Ontario’s administrator of the Conservation Authorities Act (the “CA Act”), and the Ministry of Natural Resources (“MNR”) have each announced proposals for new guidance and regulations relating to conservation lands and flood management, each of which are discussed in this bulletin.

First, the MNR published a proposal on June 12, 2026 to update the technical guidance used by municipalities and conservation authorities with respect to mapping, identifying and managing flood hazards.¹ The primary intention of this proposal is the modernization of the MNR’s 2002 Technical Guide – “River & Stream Systems: Flooding Hazard Limit” guidance document ( the “Technical Guide”). The comment period for this guidance has closed as of the date of this bulletin.

More recently, on July 29, 2026, the MECP released its proposal for two new regulations under the CA Act.² The proposed regulations follow Ontario’s restructuring of the province’s watershed management framework including the original 2025 proposal to consolidate the province’s conservation authorities and the 2026 amendments to the CA Act through Bill 97, as discussed in our previous bulletins. The current proposals focus on the governance of the regional conservation authorities and member eligibility criteria.³ The MECP is seeking feedback on the two proposed regulations, the comment period for which closes on September 12, 2026.

Though published by separate ministries, the proposals are interrelated. The MNR’s technical guidance will influence how flood mitigation is approached, a responsibility that ultimately rests with conservation authorities. Under the CA Act, conservation authorities are mandated to, amongst other things, manage flood lands in a way that prevents floods and their adverse effects. The members who govern these authorities will oversee implementing the guidance and selecting flood-mitigation technologies to be used within their regional boundaries. As such, the members appointed to an authority through the proposed member regulations become responsible for the adoption and application of the proposed flood-mitigation guidance.

Technical Guide – River & Stream Systems: Flooding Hazard Limit

The MNR seeks to update the Technical Guide, which is now dated and as a result fails to reflect advancements in the science and technology important for flood mitigation and management.⁴ The current guidance makes reference to dated software and practices used for mitigating flood risks. The MNR’s proposal acknowledges the need for an upgrade by way of a replacement guidance structure.

The MNR proposes a two-prong replacement to the 2002 guidance. First, an updated Technical Guide document, which is largely concentrated on hydrology and hydraulics to account for the advancements made in those technologies as applicable to flood risk management.⁵ The major proposed updates to the Technical Guide include:⁶

• Recommended hydrologic technologies and modelling protocols.
• Recommended practices for informing water level calculations and flood line delineations.
• Recommendations on hydrologic model selection and calibration.
• Improving suitability of hydraulic analyses for water level estimation across diverse provincial bodies of water.
• Guidance on choosing a hydraulic modelling technique and how to use such techniques in accordance with Ontario’s policies.
• Guidance on hydraulic model calibration, testing and sensitivity.
• Guidance on navigating errors in hydraulic model simulation results.

In addition to these core areas of change, the Technical Guide will inform users on Ontario’s policies on flood hazard delineation,⁷ the approaches and procedures that support hydraulic and hydrologic analyses for flood mapping,⁸ and offer guidance on ice-induced flooding procedures.⁹

The second prong of the modernization plan is the Technical Bulletin – Special Flooding Hazard Conditions in River and Stream Systems (the “Technical Bulletin”) focusing on the use of structural measures in flood mitigation and mapping.¹⁰ The proposed Technical Bulletin would result in a significant change to the 2002 guidance, which did not support structural measures as permanent forms of flood protection,¹¹ by providing recommendations on utilizing structural measures, like flood mitigation structures in flood hazard mapping, and guidance for mapping and modeling special flood hazard scenarios.¹² Moving away from the 2002 guidance, the Technical Bulletin would open the door to consider structural measures like dams, dykes, berms, flood walls and other protection landforms.¹³

The MNR does not anticipate any additional costs or consequences associated with these updates, and any guidance or recommendations proposed should be read concurrently with current best practices.¹⁴

Conservation Authority Governance Regulations

In our bulletin Ontario’s Budget Bill Advances Conservation Authority Consolidation, we detail Bill 97 and some of the major amendments it made to the CA Act, including the intention to create a centralized transition process to amalgamate 36 conservation authorities into 9 authorities. The MECP’s recently proposed regulations for conservation authority governance represent steps towards facilitating that transition in advance of the amalgamation date on February 1, 2027 (or a later prescribed date), as designated by the CA Act.¹⁵

The first regulation proposes a method to determine the number of members to be appointed to each regional conservation authority. The proposed method would replace the current approach to member appointment and would follow the below basic principles:

• The number of members to be appointed by a municipality will be determined by that municipality’s population share in the region with certain designated exceptions.
• Each municipality will have at least one member to ensure each municipality has representation.
• There will be a set maximum number of members for each municipality as well as a maximum number of total members in a conservation authority to support effective governance through a manageable number of members.

The proposed second regulation relates to Ontario Provincial Conservation Agency (the “OPCA”) board member ineligibility.¹⁶ The regulation proposes criteria that would make specific individuals ineligible for appointment to the board if they are:

• A registered lobbyist under Ontario’s Lobbyists Registration Act.
• A current member of a Conservation Authority.
• An individual currently employed as an officer or senior staff member of a Conservation Authority.

The MECP provides that this proposed regulation aims to prevent conflicts of interest, undue influence, and inspire public confidence in the OPCA.

Considerations and Looking Forward

Both sets of proposals represent movement towards more comprehensive and concentrated efforts of provincial watershed management both at the governance and project planning level. With respect to the Technical Guidance, it will be important for local entities and planning authorities to understand what developments have been made in the use of hydrologic and hydraulic systems for flood-risk management and how they can be implemented across the province’s diverse watershed systems. This is particularly true as governance over these systems becomes centralized.

From a governance perspective, municipalities will likely want to consider whether the representation allocated to them through the proposed CA Act system reflects the contributions they will make to the regional authority. While the proposed method is predicated solely on a population-based methodology, municipalities may wish to make submissions for alternate ways to determine representation beyond population share, for example financial contributions or their physical sized share of protected areas in the new authority’s jurisdiction.

Footnotes

1 Ministry of Natural Resources, “Technical Guide – River and Stream Systems: Flooding Hazard Limit and Technical Bulletin – Special Flooding Hazard Conditions in River and Stream Systems” (12 June 2026), online: Technical Guide – River and Stream Systems: Flooding Hazard Limit and Technical Bulletin – Special Flooding Hazard Conditions in River and Stream Systems | Environmental Registry of Ontario [Technical Guidance Proposal].

2 Ministry of the Environment, Conservation, and Parks, “Consultation on Proposed Governance Regulations for Regional Conservation Authorities and the Ontario Provincial Conservation Agency” (29 July 2026), online: Consultation on Proposed Governance Regulations for Regional Conservation Authorities and the Ontario Provincial Conservation Agency | Environmental Registry of Ontario [Governance Regulations Proposal].

3 Ibid.

4 Technical Guidance Proposal, supra note 1; Ministry of Natural Resource, “Technical Guide – River and Stream Systems: Flooding Hazard Limit” (2002), online (PDF): River & Stream Systems: Flooding Hazard Limit.

5 Ministry of Natural Resources, “Draft 2026 Update Technical Guide – River and Stream Systems: Flooding Hazard Limit” (2026), online (PDF): Technical Guide – River and Stream Systems: Flooding Hazard Limit [Technical Guide], see ss 3, 4, 5.

6  Ibid.

7 Ibid at s 1.

8 Ibid at s 2.

9 Ibid at s 6.

10 Ministry of Natural Resources, “Draft 2026 Update Technical Bulletin – River and Stream Systems: Flooding Hazard Limit” (2026), online (PDF): Technical Bulletin – Special Flooding Hazard Conditions in River and Stream Systems [Technical Bulletin]; Technical Guidance Proposal, supra note 1.

11 Technical Guidance Proposal, supra note 1.

12 Technical Bulletin, supra note 10.

13 Ibid at s 3.

14 Technical Guidance Proposal, supra note 1.

15 Plan to Protect Ontario Act, 2026, S.O. 2026, c. 2 – Bill 97 at Sch 3, s 2, adding CA Act, ss 1.2(1) “transition date”, 1.3(2), Table to s 1.3.

16 Governance Regulations Proposal, supra note 2.

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The foregoing provides only an overview and does not constitute legal advice. Readers are cautioned against making any decisions based on this material alone. Rather, specific legal advice should be obtained.

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