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Conservation Authority Flood Management

Prevention - Providing flood risk information to municipal planners and the general public to promote proper land use planning and regulation of 2016 CO Flood Infrographic REV Mar31new and existing development on flood plains thus preventing or reducing flood risks to people from living and/or working in flood prone areas.

Protection - In order to protect against flooding, CAs have constructed and maintain protective infrastructure such as dams and dykes or purchased lands located in hazardous areas. In the past, both the provincial and federal governments have contributed to these projects. 

Emergency Preparedness and Response - It is imperative that existing flood risks are understood and that floods are forecasted to the extent possible. Understanding flood risk and providing advance warnings is critical to allow municipalities to prepare and implement plans which allow quick response to emergency situations created by flooding. 

Conservation Authority Roles and Responsibilities CO Flood Banner B

Conservation Authorities are responsible for monitoring and predicting flood flows and water levels within their watersheds, operating flood control structures such as dams and disseminating flood messages to local municipalities and agencies. 

Conservation Authorities work closely with the Ontario Ministry of Natural Resources and Environment Canada to provide advice to municipalities in the preparation of flood contingency plans and during the emergency response process.

Conservation Authorities and the Ontario Ministry of Natural Resources use information gathered from stream gauges, weather stations, snow surveys, meteorological forecasts and computer models to forecast potential floods.

Programs and services to prevent and control flooding offered by Conservation Authorities include

  • monitoring conditions;
  • computer modeling and forecasting flooding;
  • issuing of flood messages;
  • regulation of development in flood prone areas;
  • providing planning support and advice to municipalities to minimize the impact of flooding;
  • land acquisition;
  • protecting significant ecosystems such as wetlands and forests that help to control flooding; and educating the public.

Conservation Authority Roles and Responsibilities For Flood Control and Prevention Presentation (4 MB - PDF)

Conservation Ontario Flood Fact Sheet (2012)


The most severe flooding on record in Ontario occurred in October 1954 when Hurricane Hazel passed into southern Ontario. Eighty-one people died and damages were estimated at over $180 million. Following the devastating impact of Hurricane Hazel, a flood forecasting and warning system was established in the province. Several flood control facilities were significantly upgraded or constructed following Hurricane Hazel.

Operational practices were designed to respond immediately to changing conditions. Regulations were put in place to limit and control future development and inappropriate land use activities in flood hazard areas. To manage and ensure continued viability of the provincial flood forecasting and warning system, a committee made up of representatives from the OMNR, CAs and Environment Canada was created to provide advice and training.

As part of the overall provincial flood system, MNR and CAs monitor watershed conditions including snow conditions, precipitation and flows, and when appropriate issue flood messages. CAs continue to work with municipal provincial and federal government partners to prevent damages by floods.