Natural Hazards

Natural events that can pose a threat to humans, their property, or the environment are natural hazards. Natural hazards are often equated with extreme rainfall or snowmelt, fog events, snow/ice storms, forest fires, tornadoes, and earthquakes.

Flooding and Erosion

  • Flooding and erosion, in particular, are natural hazard concerns in Conservation Halton’s watershed;
  • Threats directly associated with flooding and erosion include property damage, personal injury, or loss of life, as well as impacts to water quality and the area’s animals and plants;
  • Floods happen when water levels rise and cover the land—the floodplain—adjacent to a river, stream, or lake; 
  • Floodplains are Nature’s way of slowing and dealing with the onslaught of extra water that comes from extreme rainfall or snowmelt, or as the result of debris (natural or otherwise) or ice blocking a watercourse; 
  • Erosion (an important natural process) increases during floods, including when the torrent of extra water does not overflow a stream’s or river’s banks onto the floodplain;
  • Increased erosion can weaken the stability of stream banks and other slopes by, for example, interfering with the slope’s drainage system. Weakened banks and slopes have an increased risk of failure;
  • Land-use changes (associated with how we live and grow in an area) and climate change (now associated with an increase in the number and severity of storms we experience) are considered by Conservation Halton in their efforts to balance human, environmental, and economic needs while protecting Ontario’s water, land, and natural habitats;
  • All of us in Conservation Halton’s watershed—residents, property owners, businesses—reap the benefits of Conservation Halton’s water control program and flood warning initiative.

Hurricane Hazel in 1954, and the catastrophic flooding it caused, was the driving force for the proliferation of Ontario’s conservation authorities. In Ontario alone, 81 people lost their lives, and 4,000 families were displaced from their homes. Since Hurricane Hazel, regulations and policies to prevent home construction and other development projects in ravines or floodplains have been implemented to help protect us from similar tragedy.

How Conservation Halton Protects Us from Flooding and Erosion Threats

Time and tragedy have taught us the importance of considering and respecting flood risk in the choices we make for human growth and development in an area. To help ensure that the natural hazards of flooding and erosion do not lead to loss of life or property, Conservation Halton staff focus much of their efforts on flood-risk prevention and protection. 


Conservation Halton is committed to supporting development decisions that safeguard human life and property while protecting the natural features of our watershed. Staff of Conservation Halton’s Planning and Regulations Department review development proposals to determine how the proposed works may impact upon, and/or be impacted by, the natural environment. Conservation Halton has the regulatory responsibility to ensure that works are not permitted in areas of natural hazards in order to prevent the loss of life and property. Key in this is preventing home construction and other development projects within ravines or floodplains. 


Protection services are provided by Conservation Halton through their water control and flood warning program. 

Water control comes in the form of dams and flood control channels. To protect us and reduce the risk of property damage and loss of life due to flooding, Conservation Halton is responsible for the maintenance and operation of four major dams and 12.5 kilometres of flood control channels. The dams are all designed to control flooding as well as augment stream flows during periods of low water. The flood control channels were constructed to convey and in some cases divert floodwaters away from historically developed flood-prone areas. 

To assess risk and issue flood warnings, Conservation Halton continuously monitors weather and flood conditions in the watershed. Monitoring weather and flood conditions is a shared responsibility of conservation authorities, the Ontario Ministry of Natural Resources, and Environment Canada. When flooding is possible or about to occur, Conservation Halton will issue flood warning messages to municipal emergency management officials and the media. The municipal officials would then take action to warn local residents.

Floods and You

If a flood message is issued in your area, take heed and follow the advice and instructions of the emergency response authorities. As a precaution, consider what you can do in advance to be prepared for flood emergencies.


The following information can help get you started in thinking about emergency preparedness and developing an emergency plan for you and your family:

  • Halton Region has compiled information on what you can do before, during, and after a flood to safeguard yourself and your family;
  • Ontario Ministry of Natural Resources has compiled some emergency management facts on floods;
  • Environment Canada also has information on what you can do before, during, and after a flood to safeguard yourself and your family.

More Information