I’m installing a rain garden in my front yard next spring. It’s part of a complete overhaul of my front garden that is making my husband Max nervous.
Twenty years ago we removed the front lawn and planted a garden, but things change and I now see the need to plant more natives. And at the same time, collect and treat my own rainwater on site.
A rain garden is simply a concave area planted heavily with native plants, that collects and cleans the rainwater from your downspouts before returning it to the ground. Collects it from your property to keep it from running down stream. Cleans it so when it does get back into the ground, it does not pollute our drinking water. A great place to see one in town is in the middle of the Early Street Community Garden.
In my practice as a landscape architect I’ve been designing rain gardens for over 10 years, and am continuing to modify my techniques as I monitor them and see what was successful and what was not.
The first ones I designed were installed only to solve stormwater problems for my clients. But more and more environmentally conscious homeowners are installing them.
Most towns today have ordinances that require you to manage your stormwater if you are increasing your impervious coverage by enlarging your patio or putting an addition on to your home.
In Princeton for example, if you add 500 square feet to your home, you need to store two gallons per square feet, or 1000 gallons of water onsite.
Why do towns require this? For one important reason. To keep your downstream neighbors from flooding. Max should understand this. He grew up in Wayne and remembers people from low-lying neighborhoods parking their cars on his street when heavy rain was called for.
Does it work? You bet. With added benefits.
Right now, water comes off my roof, goes down my driveway and directly into the street. There it picks up pollutants: Oil and volatile organic compounds, and dumps them into the closest storm drain. From there it gets piped into the nearest waterway, in my case Speedwell Lake.
That’s right. With all the sediment and debris it picked up along the way. These pollutants and excess fertilizer runoff are degrading this lake. The excess nutrients in the water cause a dense growth of plant life, and death of animal life from lack of oxygen.
It is also part of what caused the HAB –or harmful algae bloom– in Lake Hopatcong this summer, which caused it to be closed to swimming all summer long. Max definitely understands that. He does water testing there and has seen the problem firsthand.
We could wait for our government to solve this stormwater problem. Yes, the same government that still hasn’t banned single-use plastic bags in grocery stores. Or we can do it ourselves.
Mine will be kidney-shaped, about 12 feet long, eight feet wide and 10 inches deep. That’s almost three cubic yards of soil Max will take out.
It will collect water from the front side of my house, where the leaders now dump onto my driveway. Because I have a basement, it needs to be 15 feet from my foundation.
Here’s how it works. I’ll plant it with some of my favorite rain garden plants: Perennial Sunflowers, Switch Grass, Iris and False Indigo. These plants have evolved here in our climate, with wet springs and dry summers, and have developed long roots, reaching deep into the ground for water.
It’s these roots that act as conduits. The roots on some of these plants reach down pretty far. Black-eyed Susans go down five feet, but False Indigo can reach down over 10 feet!
As the water travels down through the top layer of soil, it gets cleaned by the plants and microbes. Once my plants have established decent roots, my rain garden should not hold water for more than 36 hours, so mosquitoes are not a problem.
And the added benefit is this: Creation of habitat for birds, butterflies and insects. By planting a rain garden I am increasing the biodiversity of my neighborhood. This is important because our local woods are becoming less diverse and smothered with exotic invasives.
Much of our local airborne wildlife depends on a diverse population of native plants, and our suburban habit of perfect lawns and tidy shrubs has failed them. Their numbers are declining because of the loss of biodiversity. We can no longer live like we are the only species on this planet. We need to plant native plants, and lots of them. A rain garden is one way to do that.
Carolle Huber is a local landscape architect, and a founder of Grow It Green Morristown. See more of her blog posts at www.carollehuber.com