More than 4,000 plants rooted into the station’s soil-covered rooftop help moderate the building’s interior temperature. The layer of plants in 5 inches of soil acts as insulative mass, keeping the interior building space cooler during summer months. During west central Oregon’s notoriously wet winters, the roof acts as a big biological sponge, drinking up rainwater before it hits the gutters and flows over the site as roof runoff.
These rooftop plantings work in concert with the overall site design. Because the station is located near the Willamette River, designers paid close attention to maintaining water and soil quality at and around the site. Bioswales are landscape elements filled with vegetation, compost, and riprap to capture pollution and silt from on-site surface runoff before it can make its way into the watershed. A variety of plants in the bioswales filter some toxic pollutants and sediments out of the water, and microorganisms in the soil further break down pollutants.