“It's definitely worth it,” said James Gill, a resident of Madison who installed a rain garden in his front yard this summer. “It's definitely beneficial to your lot and landscaping.”
A rain garden is a shallow depression filled with native plants. Rain gardens can help manage stormwater by capturing rainwater runoff from roofs, driveways, patios and lawns, and temporarily holds the water as it filters into the ground.
Flash flooding in Madison occurs when storm sewer systems are overwhelmed by heavy rains and can’t contain all of the stormwater. This is becoming a prevalent issue as Madison is experiencing an increase in rain, according to the Wisconsin State Climatology Office.
The City of Madison offers technical and financial assistance to Madison homeowners interested in installing a rain garden on their property to help reduce the chance of flash flooding by keeping overwhelming amounts of rain out of the storm sewer system.
Phil Gaebler, a water resources engineer at the city of Madison, helps with the installation of rain gardens. If a homeowner wants a rain garden, they can contact the City of Madison for help.
“The resident chips in $100 and we cover the rest. Then we build it, we plant it, and then we give the homeowner a little pamphlet about how to maintain it,” Gaebler said.
Homeowners who install rain gardens themselves can work with Gaebler on design questions. The city of Madison also holds workshops and outreach events to help educate those interested in building a rain garden.
Another individual benefit of a rain garden is a stormwater utility credit. “Part of your municipal services bill is stormwater management, so if you have a rain garden that is big enough and treats your roof, you can get a small portion of that bill taken off every month,” Gaebler said.
The main goal of a rain garden is to absorb rainwater, keeping it off the streets and out of the storm sewer systems. In addition to flooding concerns, rainwater that hits the street becomes more contaminated before entering the storm sewer system which drains into local lakes, polluting local water systems.
“Roof water is pretty clean. There's a little bit of dust, bird poop, some leaves, but it's pretty clean water compared to a street. Streets have really nasty water: tire wear, brake dust, heavy metals, and sand from winter maintenance,” Gaebler said.
Rain gardens have other benefits too. They provide food and habitat for pollinators at risk, Gaebler said. Birds and butterflies are attracted to the native habitat as well.
Replacing conventional lawns with a rain garden increases the ground’s absorption by 30%, according to the Groundwater Foundation. By increasing the ground’s absorption there is also less standing water, preventing a breeding ground for mosquitoes.
Gill and his wife, Susan Latton, have been residents of Madison for over four decades. They were drawn to the idea of building a rain garden after the flood in August of 2018.
“After that happened, we had to have a lot of landscaping done in the backyard to mitigate the potential for flooding in the future,” Gill said. The most recent landscaping is their rain garden.
Gill and Latton started their project by making an appointment at Plant Dane, a program providing native plants to Dane County residents at a discounted rate. Using aerial photos of Gill and Latton’s house, Plant Dane was able to show them the best place for a rain garden was in front of their house, Gill said.
Once the spot, measuring approximately 12 feet in diameter, was chosen, they had to remove the grass all the way down to the roots in the soil. Once the depression was made, Gill and Latton loosened the soil, added compost and planted several native plants, including sedges, coneflowers, Jacob’s ladder, and columbines.
Native plants are key to a rain garden’s function, because perennials' deep root systems help the water infiltrate the soil, according to the University of Wisconsin - Madison’s Arboretum.
Gill and Latton finished installing the rain garden by early summer this year.
“It was really doing its thing right away,” Gill said. “We had some really heavy rainstorms over here on the west side and it would really fill up with water, but the water would be gone in an hour or so.”
Gill and Latton look forward to keeping water out of their driveway and walkway. In cold weather, water froze on their driveway making it icy and slippery, and their concrete walkway became so damaged by the water they had to replace it, Gill said.
Gill and Latton encourage other homeowners to build rain gardens. “We're almost 70 and we did it ourselves. It was taxing, but it wasn't something that we couldn't do,” Gill said.
This summer, they hosted an educational event about rain gardens organized by their neighborhood association that was well attended, Latton said.
Rain gardens aren’t the only actions residents can take on their property to help keep water off the roads and out of the storm sewer system. They can also install a rain barrel, as well as permeable pavement for their driveway and walkways, Gaebler said. Rain barrels are containers that capture rainwater runoff from roofs via gutters and downspouts, however, they require more regular effort from homeowners because they need to be drained after each storm.
Permeable pavement is porous and allows water to seep into the ground below the pavement rather than runoff the pavement. Permeable pavement can be achieved using permeable paving materials or interlocking pavers with gaps in between to expose the ground for water to soak into. Gill and Latton used permeable interlocking pavers for their own backyard garden.
Rain gardens are not the sole answer to stormwater management. Due to their small size on private properties, rain gardens can only accommodate the runoff from small storms. “Rain gardens do a great job for that half inch rain,” Gaebler said. “All the water soaks into the ground, and it doesn't hit the storm sewer system. It doesn't go out of the road and cause flooding. But you get above two and a half to three inches, and they start to get overwhelmed.”
Nevertheless, the City of Madison still encourages homeowners to build their own rain gardens.
“Don't be discouraged if you don't have a lot of room,” Gaebler said. “A rain garden that fills up and then spills over into the road still does good.”
To find out more about installing a rain garden on private property, visit the City of Madison’s website or take a look at the Wisconsin Department of Natural Resources’ manual for homeowner rain gardens.
