The City of Brisbane has installed a rain garden and a bioswale in its parking lot at City Hall. Rain gardens and bioswale gardens provide a natural way to filter pollutants from stormwater runoff. When rain drops on roofs, driveways or streets, it often picks up pollutants like sediments, chemicals, oils and household hazardous waste. These pollutants then flow into waterbodies and can harm marine plants and animals, and even people if these pollutants end up in swimming areas and drinking water sources.

Rain gardens and bioswales like these installed at Brisbane City Hall, contain native plants and soils that absorb rain water and break down pollutants through naturally-occurring, biological processes. Drain lines buried beneath the garden carry the clean, filtered water to the Brisbane Lagoon.

Brisbane was able to incorporate the rain garden and bioswale into its City Hall remodel thanks to the San Mateo County Stormwater Pollution Prevention Program that provided $250,000 in grant funding for the project.

The rain garden and bioswale do not only filter stormwater but they also give an attractive look to the City Hall’s parking lot. The rain garden is showcased as landscape in front of the parking while the bioswale garden runs along the side walls of City Hall as a green area. The city encourages others to build aesthetically pleasing stormwater runoff treatment systems. “The City of Brisbane is pleased to not only provide roof and parking lot stormwater runoff treatment at our City Hall facility, but also to be able to showcase the facility to potential other adopters of these stormwater pollution prevention best management practices,” said Karen Kinser, Deputy Director of Public Works.