In Portland, Oregon there are a number of schools who have installed rain gardens. Portland has been one of the leading cities in the world when it comes to stormwater management and has a great number of good examples, some were even featured in the book I mentioned in the previous post, Rain Gardens: Managing water sustainably in the garden and designed landscape.
Astor Rain Garden
Located in north Portland, Astor School students used to look onto an asphalt courtyard that was situated in the ‘U’ shaped section of the building. In 2003-2005, the 8,000 square foot asphalt surface was completely removed and a rain garden was installed in it’s place. Some of the roof runoff is directed into cisterns while the rest flows into the garden and through a series of infiltration basins and swales. The space is used as an outdoor classroom and the students have placed bird feeders throughout the garden. There is art scattered throughout the garden and the students obviously appreciate the garden and the critters it attracts as was evident from the letter I found on display.
The project had strong community support. A series of design charrettes was put on and both community members as well as students had a chance to provide their input. Many volunteers contributed an estimated 4,000+ hours installing the garden.
Read the project sheet from the City of Portland on their website: Astor Elementary School Rain Garden
 Astor Garden Student Letter |
 Astor Rain Garden Sign |
 Astor Rain Garden |
 Astor Rain Garden Art |
Mt Tabor School Rain Garden
The Mt. Tabor rain garden is only one piece of the stormwater management for the school. There are also swales, infiltration planters and street curb extensions, but the rain garden is the center piece. Like Astor Elementary School, the Mt. Tabor rain garden replaces a large 4,000 square foot, asphalt area with a rain garden that manages stormwater runoff from the roof. Now students overlook a green space full of plants. The design has been overwhelmingly successful earning the landscape architect a design honor award from the ASLA. You can read about the project with many photos and a plan drawing, on the ASLA website: General Design Honor Award.
Read about the system as a whole on the City of Portland website: Mt. Tabor Middle School
 Mt. Tabor Sign |
 Mt. Tabor Rain Garden |
 Mt. Tabor Rain Garden Downspout |
 Mt. Tabor Rain Garden |
Glencoe Elementary Rain Garden
Glencoe Elementary has the first rain garden in Portland and the 2,000 square foot garden manages stormwater from 35,000 square feet of impervious surface. The rain garden has much of the same benefits as the other two, it serves as an outdoor classroom and helps prevents local flooding. Glencoe is a little different however, because it is also a 4-H Wildlife Steward school and has created a wildlife garden right next to the rain garden. It’d be interesting to go back and see if they have incorporated the rain garden and found a way to combine it with their wildlife garden.
Read more about the project from the City of Portland website: Rain Garden at Glencoe Elementary School
 Glencoe Elementary 4-H Wildlife Habitat |
 Glencoe Elementary Wildlife Habitat Garden |
Enjoyed reading the case studies. Which site manages stormwater runoff most effectively or is not useful to make such a comparison?
I think it’s very useful to make the comparison, the problem is whether or not they’re being monitored. I’m not aware that Astor or Mt. Tabor is monitored and I haven’t found any information about performance since installation. The Glencoe rain garden was tested shortly after installation, but I’m not sure if it’s still undergoing monitoring. You can read the report from the City of Portland, Flow Test. It would be more interesting now, after it’s been installed for a few years, to see again how it’s working.
It may be worth looking into the next time I head to Portland, that would be a fun research project. I find the Mt. Tabor interesting because that project most closely follows the ‘stormwater chain’ that is addressed in the Rain Gardens book so in theory, it would manage more effectively because it has the most systems. The other two are, as far as I know, just rain gardens.