Floodplain Mapping Updates

Flood Hazard Mapping Studies

We’re updating our floodplain maps to reflect changes to the flood hazard limit as a result of land use changes and the way water moves over both natural and built landscapes.

Watershed floodplain mapping identifies flood risk and hazards. This information is used to develop our regulation mapping for review associated with the Conservation Authorities Act and Ontario Regulation 41/24. The maps are also used to support flood risk management decisions and communications.

Working closely with our municipal and provincial partners, we’re advancing new technologies and analysis methods—including modern hydrologic and hydraulic modelling and advanced technical studies—to update floodplain maps and improve our understanding of flood hazards across the Credit River Watershed.

As mapping reviews progress, the approximate regulation limit will be refined, which may result in the identification of new hazard or regulated areas, while others may be removed. These updates ensure our regulatory mapping remains accurate and responsive to evolving conditions, helping us better manage flood risks under Ontario Regulation 41/24 and safeguard people, property and infrastructure.

Importance of Floodplain Maps

Up-to-date floodplain maps are essential to:

• Guide land use and development decisions
• Define regulatory flood hazard areas
• Help municipalities and residents understand which areas are prone to riverine flooding
• Support flood preparedness and safer communities

Understanding the Floodplain

A river’s floodplain is the low-lying area around a river that becomes inundated during high-flow events. Floodplain maps show the flood hazard limit which is the maximum extent of flooding expected during a regulatory storm, defined as the greater of Hurricane Hazel or the 100-year storm.

Floodplains are critical natural infrastructure by providing space for water to spread and thereby reducing flood impacts in developed areas. A key factor influencing riverine flooding is land use change and development. Development often increases the amount of water entering rivers and creeks and therefore, expands to the flood hazard limit. Accurate mapping is vital to reflect these changes and manage flood risk effectively.

Areas where Mapping Updates are in Progress

We’re working with our municipal partners to update the flood hazard limits for multiple areas within the Credit River watershed. Additional areas will be added over time.

Monora Creek

Located in the Town of Orangeville and the Town of Mono, Monora Creek has four main tributaries: Upper Monora, Middle Monora, South Monora and Lower Monora.

The majority of the area around the creek is currently undeveloped but development is anticipated.

Mill Creek

Mill Creek is located south of Monora Creek in the lower part of the Town of Orangeville and the Town of Amaranth.

Land uses in the downstream areas of the creek are mostly made up of low-density residential neighbourhoods interspersed with commercial and industrial land uses. The upstream areas of the creek are primarily dominated by agricultural fields.

The creek’s downstream area lacks flow control, potentially raising flood risk. Historic flooding has has been reported  near Mill Creek  during several flooding events over the past 10 years.

Huttonville Creek

Huttonville Creek is located is the City of Brampton. It begins as two branches, East and West Huttonville Creek, which join just north of Bovaird Drive and continues south to the Credit River near Queen Street. 

The Huttonville Creek watershed is characterized by a variety of land uses, including residential areas, greenspaces, commercial areas, agricultural areas, and industrial sites. Flooding has occurred at the creek in some areas in recent years as the surrounding area continues to develop . 

We’re updating the floodplain mapping for Huttonville Creek to better understand how the creek behaves during major storms and how future growth may affect flooding.   

Springbrook Creek

Springbrook Creek is located within the City of Brampton, between Huttonville Creek and Churchville Creek. It’s a tributary of the Credit River, joining the Credit River just north of Steeles Avenue.  

Land uses within the Springbrook Creek area primarily made up  of established neighbourhoods and parkland. Springbrook Creek has experienced flooding in recent years.  

Churchville Creek

Churchville Creek is located in the City of Brampton, east of Springbrook Creek, and it flows into the Credit River north of Steeles Avenue.  

Land use within the Churchville Creek watershed is primarily established neighbourhoods, large arterial roadways, and parkland. Churchville Creek has experienced several flooding events within the past twenty years.  

Black Creek

Black Creek is located primarily within the Town of Halton Hills, with its headwaters extending into the Town of Erin. Black Creek is a tributary of Silver Creek.  It flows southernly through the community of Acton, where it discharges to Fairy Lake before flowing easternly towards Georgetown and joins with Sliver Creek.   

Land use within the Black Creek watershed is primarily agriculture, forest and wooded swamp, and wetlands. Acton and the western part of Georgetown make up the largest areas of urban and rural development within the watershed. Acton and Georgetown have experienced several flooding events within the past twenty years.  

The Science of Floodplain Mapping

Floodplain mapping is a continuous process as factors that influence flooding change over time. These maps are developed through the following steps.

• Data Collection: Gathering historical records and on the ground field observations.
• Modeling Hydrologic and Hydraulic Processes: Using advanced computer models to simulate rainfall, runoff and water flow through rivers and floodplains.
• Integration of Critical Boundaries: Compiling existing data from the Flood Hazard Limits, Wetland Mapping, Erosion Limits and Conservation Authority Regulation Limits
• Public Feedback: Incorporating feedback from local residents and municipalities that experience riverine flooding to improve accuracy and relevance.

Project Timeline

• Data Collection: 2024 to 2025
• Data Analysis: 2025 to 2026
• Anticipated Completion of Updated Flood Hazard Maps and Reports: 2027

Project Partners

This project is funded through the Ontario Flood Hazard Identification and Mapping Program, a joint initiative of the Province of Ontario and the Government of Canada. Together, they have launched this multi-year program to develop and update floodplain mapping products with the goal of ultimately minimizing flood risk for landowners and communities across Canada.