Stormwater and Drainage Management

​Managing stormwater and drainage is key to preserving the health of urban streams and rivers.




What is Stormwater?

Stormwater is water from rain or melting snow. In urban areas, most stormwater goes into storm sewers (via the grated drains in streets), which typically empty directly into rivers, creeks or the ocean. As it travels to storm sewers, stormwater picks up pollution along the way.

How Stormwater Affects Rivers and Streams

Urban stormwater may look clean, but it can contain motor oil, gasoline, dog poo, garbage, fertilizer and other contaminants. These materials go directly into the nearest body of water, where they can be harmful to plants and wildlife. Heavy rains can also dump a lot of stormwater into streams and creeks in a short period of time, causing erosion and stirring up sediment, which makes it hard for fish to breathe.

Managing Stormwater in Urban Areas

In nature, trees and earth help absorb rain slowly, breaking down pollutants, refilling groundwater and keeping waterways healthy. Urban areas that are covered in buildings, roads and other surfaces often don't allow rainwater to soak into the ground as well as more natural areas. Modern approaches try to mimic natural processes, using green infrastructure and development patterns that allow stormwater to soak into the ground or be released more slowly into local waters. These approaches are used with more traditional infrastructure (sewers and pumps) to help protect against flood risk, especially during higher intensity rain events and in lower elevation areas.

Local and Regional Government Roles

Metro Vancouver members are using Integrated Stormwater Management Plans (ISMPs) to manage stormwater while keeping waterways healthy. Metro Vancouver supports them by facilitating information sharing, helping to develop tools and resources and acting as liaison with regulatory bodies.

Managing Urban Drainage Areas

Urban drainage areas collect and funnel rain and melting snow that falls within their boundaries. In collaboration with specific local governments, Metro Vancouver provides drainage services on certain sections of waterways within the Still Creek - Brunette River Drainage Area (the Brunette Basin) and the Port Moody - Coquitlam Drainage Area. To safely channel stream flows and reduce the risk of flooding, Metro Vancouver helps ensure that major culverts, creeks and grills are kept clear and functioning properly.

Resources for Local Governments

We have stormwater resources for local governments, including design guidelines, integrated stormwater management planning resources and rainfall studies.