What is a watershed?
A watershed is an area of land where rain and snowmelt drains into the same body of water, such as a stream, creek, river, or lake.
Protecting our watersheds is important because they provide us with environmental, economic, and social benefits.

We depend on the water that flows through our watersheds for drinking, farming, manufacturing, and recreation as well as providing habitat for fish and other wildlife. The creeks, streams, wetlands, forests, valleys and other natural features provide a variety of benefits. They help reduce pollution and contaminants from our drinking water sources, absorb rainwater during severe weather events to prevent flooding, erosion, and drought hazards, reduce air temperature during heat waves, capture and store carbon to mitigate the impacts of climate change, and support biodiversity for healthy ecosystems. Watersheds also support the mental and physical health of the people who live and work in our communities.
Conservation authorities use an “integrated watershed management” approach to steward watersheds within their jurisdictions. This approach acknowledges that resources are connected within a natural system. What happens in one part of the system will impact the entire system, and we strive to recognize and understand these relationships. This approach also helps us identify priorities and frame our strategic plan to guide our watershed programs and services.
Conservation Halton stewards more than 1,000 square kilometres. This includes the Grindstone, Bronte and Sixteen Mile Creek watersheds, and 18 smaller urban watersheds that enter Lake Ontario—from Grindstone Creek in the west to Joshua’s Creek in the east.
The Water Cycle in our Watersheds
The water cycle is a natural system powered by the sun. It moves water through processes like precipitation, evaporation, condensation, melting, and freezing. This cycle supports all life on Earth and drives critical processes such as nutrient cycling and photosynthesis.
Water flows through the ground, across land, into water bodies, and then returns to the atmosphere. Its movement is influenced by natural features like soil, bedrock, vegetation, and the shape of the land.
Human activities, such as building infrastructure and buildings, farming, and water takings from wells and surface water intakes can disturb this cycle by altering how water moves, how much is available, and how clean it is. They can change natural drainage systems, reduce infiltration, redirect water flow, and drive climate change, which intensifies these impacts.
Humans rely on the water cycle for drinking water, farming, industry, and more. It is essential to understand and effectively manage human influences on the water cycle to ensure that its economic, social, and environmental benefits continue for future generations.
Learn more about the water cycle and how humans affect it in our Watershed Characterization Report.
Watch a short view about the water cycle in Conservation Halton’s watersheds below. Please note that the video quality can be improved by clicking on the settings icon at the bottom of the video and selecting the highest video quality available.
Watershed Management
Natural assets are natural resources, such as forests and wetlands, that deliver services needed for the health, well-being, and long-term sustainability of a community and its residents. In 2019, Conservation Halton, Hamilton, Burlington, and the Royal Botanical Gardens partnered with the Greenbelt Foundation and the Municipal Natural Assets Initiative, to undertake a study in the Grindstone Creek watershed. The purpose of the project was to explore the value of natural assets in addressing natural resource issues. The final report was completed and released in November 2022. The study showed that the watershed offers approximately $2 billion in stormwater management services and about $34 million annually in other benefits, including erosion control, carbon storage, and recreation.
For more than 60 years, Conservation Halton has developed watershed management plans, which identify key resource issues and guide the implementation of programs and services to protect life and property from natural hazards. It is important to update these plans to include strategies focused on climate mitigation, adaption, and resilience.
Conservation Halton undertakes a wide range of programs and services for the benefit of watershed residents and the environment. These programs and services are either guided by watershed management plans or by legislation, such as the Conservation Authorities Act and the Clean Water Act, or by municipal and provincial priorities.
Key watershed programs and services include:
- Flood and erosion hazard management, including flood forecasting and flood warning, as well as operation and maintenance of four dams and three channels to prevent and minimize the impacts of flooding
- Environmental restoration activities on public and private lands, including project management and funding to landowners who want to restore their lands
- Community education programs to help residents understand the benefits and importance of protecting our natural resources
- Administration of regulations to restrict development in valley lands, shorelines, wetlands and other hazard lands
- Administration of the Halton-Hamilton Source Protection Program to protect current and future municipal drinking water sources
- Environmental monitoring and data collection to assess and report on watershed resource issues, conditions, trends, and risks, including development and management of geographic information system (GIS) to support data management and analysis
- Acquisition of ecologically sensitive lands, wetlands, source areas and valley lands and management of over 11,000 acres owned by Conservation Halton
- Operation of eight active parks for outdoor recreation and education