Managing water flows and levels in Ontario
Learn about the importance of Water Management Plans (WMPs) and how they manage water flows and levels at waterpower facilities in Ontario.
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Managing water flows and levels
Water Management Plans (WMPs) are issued under the authority of Section 23.1 of the Lakes and Rivers Improvement Act (LRIA).
They establish normal operating conditions for waterpower facilities and water control structures within a limited geographic boundary.
Waterpower facilities and other water control structures that are within the boundary of a WMP must maintain water levels and flows within a normal operating range.
Normal operating ranges are specified within a WMP for each waterpower facility and water control structure. A normal operating range allows for water level fluctuations in response to typical rainfall, snow melt and associated runoff.
Waterpower facilities and water control structures do not prevent flooding. Some waterpower facilities and water control structures, however, may have the capacity to provide limited relief from flooding through water level and flow manipulation.
Managing water flows and levels in emergency situations
The provisions of a WMP do not apply in the event of a declared flood, low water condition or emergency situation, where water levels may go outside of normal operating ranges due to natural causes or to ensure dam and public safety.
Types of WMPs
Most river systems in Ontario with waterpower infrastructure are managed through two types of WMPs:
River systems with multiple waterpower facilities and control structures require a complex WMP when the management of flows and levels at one facility or structure may affect the operating abilities of others on the river system. Complex plans often manage significant competing interests.
A simple WMP is used for sections of river with one or more waterpower facilities or water control structures. These generally have limited control over water levels and flows.
How to maintain an existing WMP
Requirements for waterpower facility owners and water control structure owners to maintain existing WMPs are outlined in the LRIA Maintaining Water Management Plan Technical Bulletin.
Maps of existing simple and complex WMPs can be found in Appendix A of the Technical Bulletin, which displays the locations and river extents of plans in Northwestern, Northeastern and Southern Ontario.
History of water management planning
- Commercialization of the provincial electricity market triggered the need to develop a planning framework for the consideration of new waterpower facilities and redevelopment of existing facilities.
- The LRIA legislative amendment allowed the Ministry to order the owner of an existing dam to prepare or amend a management plan for the operation and maintenance of the dam.
- The water management planning process was established to implement the LRIA legislative amendment, and existing waterpower facilities and water control structures on river systems in provincial jurisdiction were required to prepare WMPs in accordance with the 2002 Water Management Planning Guidelines for Waterpower.
- WMPs provided certainty and clarity with respect to how waterpower facilities and control structures are to be operated to balance environmental, social and economic objectives.
- This built upon previously introduced regulation and technical guidance under the Environmental Assessment Act for all new electricity generation and transmission projects (Regulation 116/01).
Today the OWA Class EA and post-EA regulatory approvals for new dams and expansion of existing facilities achieve the same objectives as the 2002 water management planning process did for pre-existing facilities. As a result:
- new or expanded waterpower facilities are no longer required to undertake water management planning. These facilities are instead required to prepare site-specific Operating Plans.
- where a new or expanded waterpower facility is located within the geographic boundary of an existing WMP, facilities will be required to follow the requirements of the WMP and the WMP will be amended to incorporate the new facilities.