Our goal used to be channeling stormwater off of our streets and yards as quickly as possible. Water, the “common enemy,” was treated as a nuisance, unwanted in the urban landscape. More recently, we have been thinking more about rainwater, and the runoff it creates, as precious resources—to be saved and used as nature intended—to replenish and renew groundwater and streams.
We’ve learned that a better idea is to slow stormwater down, allowing it time to soak into the ground. We slow it by storing it temporarily in ponds, giving time for sediment and pollutants to settle out. We try to direct runoff through vegetated channels or basin, both slowing and filtering it.
One idea that has caught on in both a residential and community scale in this regard is the rain garden. These are shallow vegetated depressions. They are just deep enough to catch and hold the first bit of runoff, which is usually the most polluted. Plants in the rain garden can be attractive, showy flowers, but their main purposes are to hold the soil in place, slow the water down, and through deep root systems provide channels where water can infiltrate. Here are some basic ideas about rain gardens:
1. Vegetation is the key. Since rain gardens are often dry, and only periodically wet, plants selected to go in the garden must be able to tolerate both conditions.
2. Native plants are a good choice, because they are pre-adapted to live in the climatic conditions found here. Many natives also develop deep root systems, speeding infiltration.
3. Rain gardens must be weeded, especially the first year, to allow the desired plants time to get well-established.
4. The soil in a rain garden must be suitable to grow the intended plants. In the thin, rocky soils of the Ozarks, soil amendments are often necessary to support the desired vegetation.
5. Rain gardens should be placed in areas of the yard where runoff is concentrated, such as just downstream of roof gutter downspouts or in shallow drainageways between homes.
6. Watershed organizations such as JRBP and Watershed Committee of the Ozarks have lots of information on rain gardens—how to build them, and what types of plants and soils to use.
Rain gardens help keep our streams and groundwater clean and have added benefits. A well-designed and maintained rain garden will be a beauty spot in the monotonous urban sea of turf. And if the right plants are selected, they will attract the butterflies, bees and hummingbirds that we love to see in our yards.
Loring
