Natural Hazards

The structure of Kelso Dam with the reservoir behind it.

Natural hazards, like flooding and erosion from extreme rainfall or snowmelt, can be dangerous for people and cause damage to properties, infrastructure and nature. Conservation Halton provides a flood forecasting, management and operations program to reduce the risk of these natural hazards from having an impact on our community through prevention, prediction, protection and precaution.


Prevention

The Permitting and Planning department at Conservation Halton works with our municipal partners to support community development that is safe and sustainable. Section 28 of the Conservation Authorities Act enables conservation authorities to develop regulations for certain activities in areas where public health and safety would be at risk because of naturally occurring processes (e.g., flooding, erosion) or where activities could either create a natural hazard or aggravate a natural hazard that already exists.

Prediction

Conservation Halton is constantly monitoring weather and watershed conditions, in collaboration with other conservation authorities, the Ontario Ministry of Natural Resources, and Environment Canada. When flooding is forecasted, Conservation Halton issues flood messages to municipal emergency management, emergency medical response, school boards, police and media.

Protection

Conservation Halton operates and maintains four major flood control dams (Kelso, Hilton Falls, Scotch Block and Mountsberg) and more than 12 kilometers of flood channels (Sixteen Mile Creek through Milton, Morrison-Wedgewood diversion in Oakville and the Hager-Rambo diversion in Burlington). The dams are designed to control flooding and augment water flow during periods of low water. The flood control channels are designed to convey, and in some cases divert, flood water away from flood-prone areas.

Conservation Halton operates and maintains four major flood control dams, which were built in direct response to the devastation of Hurricane Hazel (October 1954). Most of these facilities were constructed in the 1960s and 1970s. Since this time, flood management has shifted from expensive, engineered structures, like dam and channels, to more a passive approach, including land acquisition and development regulation.

Kelso Dam

Kelso Dam was the first flood control dam constructed within the CH jurisdiction and was built in 1962. It works in conjunction with the Hilton Falls Dam and Reservoir, which was built in 1974, and is located just upstream, to provide flood control during spring melt, heavy rainfall and snowmelt events for the Town of Milton located downstream. Kelso Dam provides low flow augmentation in summer months to support aquatic habitat in the downstream Sixteen Mile Creek. It also allows visitors to Kelso to enjoy recreational opportunities like swimming and non-motorized boating.

Hilton Falls Dam

The Hilton Falls Dam and Reservoir upstream diversion structure was constructed in 1974, the last of Conservation Halton’s dams to be built. It operates in conjunction with the Kelso Reservoir to provide flood protection to downstream flood susceptible areas within the Town of Milton during spring melt, rainfall and snowmelt events. Hilton Falls is also utilized to augment inflows to the Kelso reservoir during drier summer months by storing upstream runoff during the spring and releasing it at a predetermined minimum rate. The level of flood protection during winter months when holding levels are lower is quite high however, level of flood protection is reduced during summer in light of the higher summer reservoir levels which effectively reduces available active flood storage.

Mountsberg Dam

The Mountsberg Dam and Reservoir was constructed in 1966 and was the second flood control structure built by Conservation Halton. It is operated to provide flood protection to downstream flood susceptible areas within Lawson Trailer Park and the Town of Carlisle during spring melt, as well as rainfall and snowmelt events. Mountsberg is also utilized to augment low flows in downstream Mountsberg Creek and the Bronte Creek system during drier summer months by storing upstream runoff during the spring and releasing at a predetermined minimum rate. The reservoir also provides recreational opportunities to the public including education programs at the Mountsberg Conservation Area, fishing and boating (non-motorized).

Scotch Block Dam & Reservoir

The Scotch Block Dam and Reservoir was constructed in 1972. It is operated to provide flood protection to downstream flood susceptible areas within the villages of Mansewood and Hornby during spring melt, as well as rainfall and snowmelt events. Scotch Block is also utilized to augment flows in Middle Sixteen Mile Creek during drier summer months by storing upstream runoff during the spring and releasing at a predetermined minimum rate. The level of flood protection during winter months when holding levels are lower is quite high however, level of flood protection is reduced during summer in light of the higher summer reservoir levels which effectively reduces available active flood storage.

Conservation Halton operates and maintains three flood control channels. The channels were built in the late 1960’s and 1970’s to move water through our communities and into Lake Ontario as quickly as possible. Since this time, the way that we design our communities has changed. Today, our communities include stormwater ponds and space for creeks to flow, naturally, so that excess water can be stored and released over time after a rain event.

Hager-Rambo

The Hager-Rambo Flood Channel was completed in 1976 and is almost 4 km in length. It is intended to ease local flooding in residential areas within the City of Burlington. The Hager-Rambo diverts the flow of the upper Hager and Rambo Creeks west to Indian Creek before emptying into Lake Ontario.

Milton

The Milton Flood Channel was built in five phases, the last coming in 1979. It is 3 km in length and conveys flood waters of the Sixteen Mile Creek safely through the historic downtown area of the Town of Milton.

Morrison-Wedgewood

The Morrison-Wedgewood Channel was the first flood channel built by Conservation Halton in 1967 in the Town of Oakville. It was added to in 1969. This channel is just over 4 km long and diverts waters from residential areas north of the Queen Elizabeth Way, west to the Sixteen Mile Creek, and away from residential areas south of the QEW.

The first step to reducing the impact of flood damage within a community is to have mapping that helps us identify flood hazards, accurately. Conservation Halton is working with our partners to reduce flood risk in our communities by updating out floodplain maps, some of which are more than 20 years old. Updates to technical studies and modelling, using new tools and technologies, help us to better understand the extent of flood hazards. As mapping reviews and updates progress, refinements to Approximate Regulation Limit mapping will be necessary, as additional hazard or regulated areas may be identified and some may be removed.

How can you get involved?

Conservation Halton encourages the public to participate in flood hazard mapping studies. Public involvement provides greater certainty and transparency for the floodplain mapping program, and it benefits from receiving observations about the watershed from the people who experience these watershed conditions.

We host public engagement sessions on floodplain mapping studies to notify the public and stakeholders that a study is occurring in their area and to share information on the study process and draft mapping updates for review and input. Floodplain mapping study notifications and updates on public engagement are published in community newspapers and posted on the Conservation Halton website and social media. You can also request to be added to the email contact list for the study to receive direct notifications.