Remembering Lost Streams through Green Rainwater Infrastructure

Vancouver was once home to more than 40 creeks and streams that supported fish, birds, and other types of wildlife. Over time, those waterways were buried to make way for roads, sidewalks, and buildings, leaving an important natural legacy forgotten underground. One of those is what we now refer as St. George Creek.

For years, rainwater was treated as a nuisance, put into pipes and conveyed away as quick as possible. But there is a new movement underway to rethink this approach by using nature as an ally to help manage rainwater. Some waterways, like St. George Creek, are buried too far underground to resurface. However, by using green rainwater infrastructure (GRI) we can find new ways to honour lost streams while also providing rainwater management services at the surface.

Using thoughtful design, this rain garden has been shaped and planted to mimic water flowing in a stream

What’s the difference between Green Rainwater Infrastructure and Stream Daylighting?

Green rainwater infrastructure (GRI), uses a combination of nature-based and engineered solutions to help capture and clean rainwater. These are not just naturalized features, but are important drainage infrastructure.

Unlike a daylighted stream, water will only be visible at the surface of a GRI feature during heavier rain events. During more modest rain events, the water is readily absorbed by soil and plants and less likely to be seen flowing through the system. During rainstorms, water may move through the infrastructure very similar to water running through a stream.

An example of water entering a rain garden from the street.

Slowing down and absorbing the rainwater is an important part of how the rainwater run-off pollutions get cleaned in a rain garden. Unlike a stream, which is conveying water away, GRI manages water by encouraging it to slow down and seep into the soils. GRI may appear dry on the surface, even though the plants and soils are working effectively to filter and absorb rainwater. Landscaped GRI is well-established as an effective rainwater run-off management too that can also provide beautiful landscape to be enjoyed by people and wildlife. GRI is designed to drain excessive ponding and to generally clean and absorb all surface water within 24 hours to ensure these features are ready to handle the next rain event and do not become mosquito breeding grounds.

Rain gardens slow down rainwater and allow soils and plants to help remove pollutants

Connecting the Drops to Support Aquatic Health

Currently, much of the rainwater in the city is managed through grey infrastructure – it is captured in catch basins, conveyed through the sewer system pipes, and outfalls into local waterways like False Creek. Often, this water receives no treatment, so it carries pollutants from roadways directly into aquatic habitats.

The St. George Rainway is an example of a different approach being taken by the City of Vancouver rainwater infrastructure is planned and built. GRI not only captures rainwater, but also treats that rainwater, removing many harmful pollutants. This means cleaner water flowing into False Creek, which helps to improve ecosystems for salmon and other aquatic life.

Water is an important source of life of all living creatures. The St George Rainway is an opportunity to honour this incredible resource by helping to keep it clean.

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