What stormwater is
Stormwater is rain, melted snow or any other form of precipitation that has come into contact with the ground or any other surface. This water either seeps into the ground, is absorbed by vegetation, evaporates or runs off the land into storm sewers, streams and lakes.
Stormwater can come from any type of land – residential, industrial, commercial or institutional.
Why stormwater management is important
Stormwater must be managed for two key reasons:
- Water cycle. Our environment naturally moves water through the water cycle. To put the process very simply: Our atmosphere absorbs water from the earth, it falls back down as precipitation where it is absorbed by the soil and used by vegetation to grow. The water eventually evaporates back into the atmosphere and the cycle continues.
But we humans have interfered with this cycle – precipitation can't reach the soil through the hard surfaces we build such as roads and buildings. We've also built storm sewers to quickly drain that water away.
- Pollution. As stormwater flows toward sewer systems it can pick up toxic debris and chemicals such as fertilizers, oil and grease, pesticides, dirt, animal and bird fecal matter, other pollutants and litter.
Municipalities and developers create strategies to prevent stormwater pollution and design systems to treat stormwater and route it safely back into our natural environment.
The benefits of stormwater management
There are many benefits to stormwater management. It supports environmental sustainability by:
- minimizing or avoiding the creation of polluted stormwater
- reducing environmental impacts on the lakes, rivers and watersheds
- achieving greater harmony with the water cycle in the watershed
- potentially reducing municipal water supply requirements by using stormwater as an alternative water source
- minimizing health risks
Stormwater management also contributes to community safety and financial risk management by reducing the risk of urban flooding and erosion. The associated basement flooding and damage to public and private properties can also be avoided (in conjunction with major drainage systems built by municipalities).
Please explore the rest of this section to learn what stormwater management involves, find out what municipalities and property owners need to know about stormwater management, learn how we're adapting stormwater management for climate change, encouraging the creation and export of innovative clean-water technology and promoting water conservation.