The rain gardens are filled with sandy biosoil and planted with native vegetation.
Cleveland Metroparks’ natural resource managers are working with local citizens to improve water quality of a Cuyahoga River tributary one yard at a time.
Environmentalists, engineers, the city of Parma, Ohio, and local citizens are collaborating to build a neighborhood full of rain gardens and rain barrels abutting a city park. A series of flow meters will help the group learn if the gardens are making a difference in curbing runoff into the river.
The majority of the gardens sit within tree lawns on land considered to be owned by the City of Parma, as right-of-way property. That means, with Parma’s blessing, the team could have built these rain gardens anywhere along the street.
Instead, Cleveland Metroparks and West Creek Conservancy, a local watershed group, worked together to recruit homeowners to build the gardens. “We wanted the homeowners to adopt them,” said Jennifer Grieser, a Cleveland Metroparks senior natural resource manager who manages the program. “We wanted the homeowners to sign-off.”
She said there were ten takers, for a total of 22 right-of-way rain gardens, one front yard rain garden and 53 rain barrels. The gardens were installed in June 2013. They ranged from first time homeowners to lifelong residents. URS Corporation provided final design services for the project.
Grieser said the main motivation for the rain gardens was to clean and reduce runoff entering West Creek through headwater streams that drain out of the neighborhood. “Stormwater gushes out of street outfalls and washes away anything living in these small streams,” she said.
West Creek then flows to the Cuyahoga River, which receives heavy amounts of nutrients from sewage plant overflows during heavy rains.
Workers from the Northeast Ohio Regional Sewer District helped the Cleveland Metroparks team install ISCO flow meters so they can determine how the gardens have impacted runoff. Workers placed the flow meters before the outfall for the streets being measured.
Grieser said they made sure to install the ISCO system’s data loggers close to the manhole covers, so no one has to climb down into the sewer to collect data. “We wanted to reduce the number of confined space entries that need to be made to collect the data,” she said.
Four streets in total now have flow-logging setups. Two are treatment streets and two are control streets. This arrangement should allow for pre- and post-installation comparison as well as treatment versus control comparison.
This fall the Cleveland Metroparks team will install 19 additional rain gardens. Residents on a second street in the neighborhood will receive many of the gardens. Neighborhood buzz also spurred people from the original street to request gardens.
When building a rain garden, a team of contractors from DCH Landscaping start by digging a hole. Since Northeast Ohio often has dense clay soil near the surface, the hole has to be a bit deeper than the clay layer. “We would over-excavate the basin and then lay stone at the bottom,” Grieser said.
Contractors also install drains in the bottoms of the gardens to ensure they would not overflow or retain too much water.
Once the base of the garden is complete, the team backfills with sandy biosoil. Then they ensure their grading is correct, so that water will flow into the rain garden. In some areas they cut out a section of curb to create a channel for street runoff to enter the garden.
“After the soil is placed and the grade is correct, the key with the soil is that it doesn’t get compacted,” Grieser said.
That’s where native and perennial plants come in. Their roots help keep the soil loose so water can pass through. They also absorb nutrients, such as lawn fertilizer.
Grieser said homeowners will need to maintain the rain gardens but the West Creek Conservancy will recruit volunteers to aid with maintenance.
There are no released data on runoff reduction yet. Cleveland Metroparks workers are still collecting and processing flow measurements.
A Great Lakes Restoration Initiative grant has made the rain gardens possible. The Northeast Ohio Regional Sewer District and Northeast Ohio Areawide Coordinating Agency also contributed funds to the project.
Top image: The rain gardens like this right-of-way project are filled with sandy biosoil and planted with native vegetation.