Around the House: Rain Gardens - Style One
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a rain garden program that has resulted in some 700 home garden rain gardens and 60 rain gardens on city land, most of them installed by the city during redevelopment and planted and maintained by residents. Early in the project, a University of Minnesota study estimated that the city had saved $13,000 by investing in rain gardens rather than conventional gutters and piping in just a two block stretch. The project, over the years, has also had a significant impact on local ecology. Not bad for a city of 40,000.
On a much smaller scale, individual home rain gardens can also have an immediate impact, and they’re not that hard to create. The first step is to find an appropriate location. Ideal spots include areas downhill from paved surfaces, existing low spots (but not where it actually pools, since the soil is likely too dense to handle a rain garden without some serious amendment), and places where downspout extensions can funnel water directly to the garden area. Areas with partial or full sun are generally better than fully shaded areas as well. Do make sure that the area is more than 10 feet from your house so you’re encouraging water to infiltrate the ground rather than your home’s foundation.
Spring is coming faster every year, and it’s never too early to start planning the gardens of your dreams. Garden catalogs have been arriving at our house thick and fast, and my four-year-old pages through them identifying the plants he’d like to have in his garden (hint: it’s pretty much all of them). Each year my wife tries to add a little to the garden beds in our yard, which were a solid mass of grass, trumpet vine, and nightshade when we moved into the house. Of course it’s a bit too early, and still too wet and slushy, to start in earnest, but we’re always considering what we should do for our next project. This week, as we navigated the death trap that was our driveway, sliding over sheet ice and into slightly greasy sludge puddles on our way to our detached garage, the reality of water as part of Minnesota’s climate was literally hard to avoid. There was nowhere for the water to go, so it pooled deeper and deeper until it finally ran down the driveway to the street, carving deep channels in the ice before finally finding a storm drain. This was not particularly nice water, and as much as we wanted it out from underfoot, we didn’t love the idea of it running into the river with its technicolor oil slicks and promise of antifreeze and heavy metals. So this year we’re considering creating a rain garden to keep more water – and the things it carries – contained.
Rain gardens are essentially natural catchment systems for potentially polluted rain and meltwater. Planted near downspouts or in low lying areas where water naturally collects (which you can find by sending your son outside with instructions to keep his shoes dry or can create yourself), they are designed to absorb runoff quickly and filter it on its
way back to the water table. According to the Mid-America Regional Council (MARC), a rain garden can absorb 30% more water than an area the same size planted with grass, and when planted correctly, they can be extremely effective. The Ramsey-Washington Metro Watershed (RWMW) reports that rain gardens can trap as much as 99% of common pollutants like fertilizers, heavy metals, sediment, and oil, as well as other chemicals like nitrates, ammonias, and phosphorus. They also help to prevent flooding and both the damage to structures and erosion of stream beds that floods can cause.
Rain gardens can have a major impact, economically as well as ecologically. Since 1996, the city of Maplewood has implemented