Rain Gardens and Bioswales in Greenfield
Many efforts are being made throughout Franklin County to protect our waterways by diverting contaminated stormwater runoff from buildings and roads into rain gardens or bio-retention swales. To learn more about these efforts see the FRCOG Green Infrastructure webpage.
Here we highlight rain gardens and bioswales within the Greenfield city limits.
Definitions
A bioswale is a swale, or low area of land, where water is allowed to percolate into the soil. There is a drain in case the water gets really deep, but the bioswale is designed to capture all of the water from an average to moderately heavy rain storm without letting it go into the storm drain. You tend to see bioswales in newer housing developments or downslope from ball fields where runoff has been a problem.
A rain garden is purposely created to collect water from roofs and sidewalks. It might not be sited in a spot that is already low - typically, rain gardens are placed where they can collect water from downspouts, and the land is reconfigured to hold the water while it percolates into the soil. Either a rain garden or a bioswale is planted with water-loving plants that can also take drier conditions in case of low rainfall, but a rain garden is more 'garden' like while a bioswale is more like tall-grass prairie. Rain gardens are usually put in by homeowners to control water on their property without taxing the storm sewer system, so a rain garden doesn't usually have an overflow drain.
The entrance to Greenfield High School is flanked by extensive rain gardens. Water from the roofs is directed to these gardens, which are planted with wetland trees, shrubs such as Itea virginica (Virginia sweetspire, in the foreground in the photo), and flowering plants. These gardens prevent flooding of the parking lots and fields surrounding the school, preventing runoff of street contaminants into local bodies of water.
Chapman and Davis Streets
At the bottom of the sloped parking lot between Chapman and Davis streets is a wide bioswale, situated to take the rainwater from the parking lot and let it soak into the ground. Plants that can tolerate both wet and dry conditions such as birch trees, red-twig dogwood, and an understory of flowers and grasses are planted here. This garden remained intact when the skate park was installed in the parking lot in late 2023. The skate park is designed to handle rainwater separately.
Olive Street Rain Garden/Bioswale.
Signage at the upper end of Olive Street explains the purpose of the stone path and plantings that take stormwater from the street, allowing it to soak into the ground. A grate at the lower end collects water that has not soaked in.
John Olver Transit Station
(between parking lot and bus entry).
John W Olver Transit Station rain garden is maintained by staff at the Transit Station.
Pleasant Street Community Garden Rain Garden
Plants such as Button Bush (Cephalanthus americanus) provide pollen and nectar for bees and other pollinators visiting the bioswale and nearby vegetable gardens.
Photo by Lee Page, courtesy of Wildflower.org.