When a summer storm drops heavy rain across the Credit River Watershed, the water must go somewhere. It moves across rooftops, streets, parking lots, yards and fields, enters streams and rivers, and eventually makes its way toward Lake Ontario. Some of it soaks into the ground. Some flows into storm sewers. And some moves across the landscape and through floodplains as it makes its way downstream. Understanding where water goes—and where it may go when rivers and streams rise—is an important part of building safer, more resilient communities.
At Credit Valley Conservation (CVC), floodplain mapping helps us understand where water is likely to go during major storm events and how rivers and streams respond when water levels rise. These maps support municipal planning, emergency management, infrastructure design and natural hazard management across the watershed.
Giving Rivers Room to Flow
A river is more than the water flowing within its channel you see.
When rivers and streams experience high flows during major storms, water can spill beyond the channel into nearby low-lying areas known as floodplains.
Floodplains are a natural part of a healthy watershed. They provide space for excess water to spread out, helping to reduce the impacts of flooding and allowing water to move safely through the landscape.
A floodplain can be dry for many years, but it is still an important part of the river system. Understanding these natural pathways helps communities plan for the times when rivers need more space to carry floodwaters.
Floodplain maps identify areas that may be affected during significant flood events, giving municipalities, planners and property owners a better understanding of flood hazards and where extra caution may be needed.
Credit Valley Conservation develops and maintains floodplain maps across the Credit River Watershed.
This work brings together multiple sources of information to build a clearer picture of how water moves through the watershed.
How CVC Maps Flood Risk
Floodplain maps are built using science, local knowledge and technical expertise.
CVC’s engineers and hydrologists analyze historical flood records, field data, rainfall information and detailed elevation mapping to understand how water moves through the watershed. Using advanced computer models, they simulate how rivers and streams may respond during major storms and identify areas that could be vulnerable to flooding.
As communities grow and rainfall patterns change, CVC regularly updates floodplain maps to ensure they reflect current conditions and the best available information.
While much of this work happens behind the scenes, it plays a vital role in helping communities, municipalities, and residents understand flood risk and prepare for the potential of future flood risks.
Turning Information Into Action
Floodplain maps do more than show where flooding may occur. They help support decisions about growth, infrastructure and public safety across the watershed.
They provide important information that municipalities, planners and other decision-makers can use when considering how and where communities grow.
They are also an important input into to CVC’s regulation mapping.
While floodplain maps identify areas susceptible to flooding, regulation mapping identifies areas that are regulated under the Conservation Authorities Act and Ontario Regulation 41/24 to help protect people and property from natural hazards such as flooding and erosion.
Together, these mapping tools help ensure that flood risks are considered when planning future development and infrastructure projects.
Explore CVC’s Floodplain Map and Regulation Mapping Viewer.
59 Stations. One Watershed. Real-Time Information.
Floodplain mapping is one part of CVC’s broader approach to understanding and responding to flood risk.
Flood forecasting and warning programs help communities prepare for changing conditions in real time.
Through CVC’s network of monitoring stations, Flood Duty Officers monitor local conditions across the watershed, along with weather forecasts and other information including our Environment Climate Change Canada partners monitoring stations, to assess river and creek conditions.
When flooding is possible or occurring, CVC issues flood messages and warning notices to help communities prepare.
This real-time monitoring complements the longer-term work of floodplain mapping. One helps us understand potential flood risk across the landscape; the other helps us understand what is happening as conditions change.
A Resilient Watershed Starts With Healthy Natural Systems
Understanding where water goes is only part of building a resilient watershed. What happens on the landscape also matters.
Healthy forests, wetlands, natural shorelines and protected greenspaces can slow, store and filter water as it moves through the landscape. Protecting and restoring these natural systems is an important part of building resilience for both people and nature.
Through the Credit Valley Conservation Foundation (CVCF), donors help support conservation, restoration and education initiatives that strengthen the natural systems that manage water across the landscape.
From protecting important lands and restoring natural areas to connecting people with nature and supporting conservation education, these projects help build a healthier, more resilient Credit River Watershed for generations to come.
The support of our local communities helps protect the natural systems that communities depend on every day—including during the storms when the watershed is put to the test.
Protecting Communities and a Healthy Watershed
Every drop has a destination.
Floodplain mapping is about more than understanding where flooding may occur. It helps us better understand how water moves through the watershed and supports decisions that protect both people and the natural environment.
Building a resilient watershed takes more than maps. It requires science, planning, monitoring, conservation and partnerships. Managing flood risk is a shared responsibility, with municipalities, conservation authorities and provincial agencies working together to monitor conditions, provide flood forecasts and warnings, coordinate emergency response efforts, and help keep communities safe.
The next time a summer storm rolls through, take a moment to watch the rain. From the moment it reaches the ground, every drop begins a journey through the Credit River Watershed. Understanding that journey helps communities prepare for potential risks while protecting the natural systems that help manage water.
Together, CVC’s science, flood forecasting and conservation and its municipal partners are working together to build a safer, healthier and more resilient watershed – for today and for the future.