An average annual rainfall for Michigan is more than 31 inches, which equates to more than 52 million gallons of rainwater per year. That much rainwater can severely damage downspouts and create pollution. A rain garden is an environmentally friendly and attractive way to filter and return storm water runoff from surfaces such as sidewalks and roof tops, while protecting our groundwater and waterways. They can be created on your own property using just a few steps – ultimately minimizing the pollution that emerges from the rainwater gushing out of downspouts.
First, determine if you have a suitable site for a rain garden. The ideal spot is one that is:
- Fed by only one or two downspouts
- Far from a septic tank, drain field, or wellhead
- Free from trees
Next, follow these easy steps:
- Find an outdoor space that can absorb water, ranging from 100 to 400 square feet. A rain garden should be about 20 percent the size of the roof, patio or pavement area draining into it.
- If there are trees in the area, make sure they can handle wet soil conditions for lengthy periods of time to ensure that your rain garden is set up for success.
- Remove the grass and dig a hole at least 2 feet deep.
- Lay an inlet pipe used for catching the storm water. These small pipes can be purchased at any hardware store for under $20.
- Add native vegetation, and you’re all set!
The benefits of rain gardens are tremendous. In addition to being aesthetically pleasing, they are easy to maintain and improve water quality by filtering out pollutants. And perhaps the most magnificent benefit is that they attract wildlife such as birds, butterflies and insects who use the plants as a food source.
The Detroit Zoological Society (DZS) is working to protect storm water on the grounds of the Detroit Zoo and Belle Isle Nature Center. We built a rain garden near the Ford Education Center, which collects rain water from the roof of the 38,000-square-foot building and is maintained throughout the entire year, incorporating native Michigan plant species. The downspouts drain into the garden through a pervious pipe located 3 feet below the surface. We’re in the midst of creating a second rain garden near American Coney Island. Native, drought-resistant plants have already been planted and we plan to build a mock house with gutters and rain barrels. Signage will educate guests about how they can incorporate rainwater collection and rain gardens at their homes. In addition, we have incorporated permeable pavement within parking lots and public walkways, which also reduces storm water runoff and improves water quality by filtering out pollutants.
We all have an impact on the planet – projects like these are simple steps we can take to make sure it is a positive one.