Frequently asked questions

A multi-block series of green rainwater infrastructure designed to acknowledge a historic stream. The green rainwater infrastructure collects and cleans rainwater from surrounding areas such as streets, sidewalks, and laneways to honour the lost stream.

The infrastructure systems in place that manage rainwater, which can include catch basins, pipes, ditches, and green rainwater infrastructure.  

Green rainwater infrastructure (GRI) is an approach to rainwater management that uses a combination of engineered and nature-based solutions to protect, restore, and mimic the natural water cycle. Rainwater running off of hard, impermeable surfaces such as roads, sidewalks, and rooftops is captured, stored, and filtered. The water then rejoins the water cycled by absorbing into the ground, returning to waterways and/or the surrounding atmosphere.  

GRI is both a drainage infrastructure tool as well as a method to manage and enhance urban water and natural systems. When integrated with grey infrastructure (traditional sewage and pipe systems), GRI can provide environmental, social, and economic benefits.   

There are many types of green rainwater infrastructure.  Some of the common ones seen in Vancouver include rain gardens, rainwater tree trenches, and permeable pavement.  

Rain gardens (also called bioswales or bioretention) are shallow gardens that feature layers of rocks, engineered soils, and vegetation such as trees, shrubs, and flowers. They help to capture and clean rainwater.  

Rainwater Tree Trenches use trees along with underground structures and perforated pipes for rainwater management. Structures underground provide extra room for tree roots to grow while also storing rainwater that can be used by trees.  

Permeable Pavement is a special type of surface used on roads, sidewalks, driveways, and parking lots that allows rainwater to pass through the pavement and soak into the ground.

The rainwater that falls on our hard urban surfaces – also known as urban rainwater runoff - collects pollutants found on our rooftops, streets, parking lots, and other hard surfaces. These pollutants are then conveyed with the water through the sewer system to our treatment plants, or directly into local waterbodies.

Pollutants commonly found in rainwater include: 

• Hydrocarbons and petroleum pollutants
• Bacteria and viruses
• Heavy metals
• Litter
• Nitrogen and phosphorous
• Micro-plastics
• Sediment
• Salt

Green rainwater infrastructure captures and helps clean rainwater before the water infiltrates into underground aquifers or is conveyed through the sewers to surrounding watersheds. A number of studies both in the laboratory and field have proven that GRI is able to capture and help treat rainwater pollutants with the exception of salt.  

Daylighting is a process in which part of a creek which has been buried underground in a pipe gets exposed to the surface. 

We recognize that many in the community have a desire to celebrate and restore natural systems, including lost streams. In this case, it is not part of the scope to ‘daylight’ (or bring to the surface) the existing buried stream, as it has been buried too deep underground to make this possible. 

Instead, the rainway will manage local rainwater runoff at the surface using green rainwater infrastructure along St. George Street. Through thoughtful landscape design, artwork, and signage, we hope to honour the lost stream while also enhancing the local environment.