Rain garden FAQs
What is a rain garden?
Why is stormwater a problem?
What is an impervious surface?
What is non-point source water pollution?
How else can I reduce impervious surface on my property?
Why native plants?
What kinds of plants go in a rain garden?
What’s the difference in the function of a rain garden and a rain barrel?
Where else can I learn about rain gardens?
Can I hire someone to build a rain garden in my yard?
What is a rain garden?
A rain garden is a garden with a shallow depression which is strategically located on a property to capture stormwater runoff from impervious surfaces, such as rooftops, patios, driveways, and parking lots, before it enters the storm water system. The water is held by the garden and allowed to slowly infiltrate the soil. The soil and plant roots use natural processes to improve water quality by filtering pollutants, the overall amount of stormwater runoff is reduced, and the groundwater supply is recharged.
Why is stormwater a problem?
Most modern American cities are built in such a way that when it rains, all of the water is directed immediately into storm sewers via gutters, curbs, and ditches and then out into nearby creeks and streams. On its way to the stormwater system, the rain water picks up pollutants such as motor oil, grease, pet waste, fertilizers from lawns, and other toxic substances. The water then rushes out all at once from storm sewers, severely eroding the banks of the creeks it is directed into and bringing all of the pollutants from the city into the water. This is called non-point source pollution.
What is an impervious surface?
An impervious surface is any surface that doesn’t allow rain water to penetrate into the soil. This includes roofs, roads, cement or gravel driveways, sidewalks, and most lawns (because the shallow, dense root system acts almost like cement). Impervious surfaces contribute to increased amounts of stormwater runoff, increased non-point water pollution, and the urban heat island effect.
What is non-point source water pollution?
Point source pollution is that which is sent directly into streams, creeks, and rivers via pipes. Non-point source pollution then is any other pollution that makes its way into these bodies of water, usually via stormwater runoff. That includes sediment (from erosion and agriculture), pesticides, fertilizer, pet waste, agricultural runoff, salt from the roads in winter, motor oil, grease, and litter.
How else can I reduce impervious surface on my property?
Replace your concrete or gravel driveway with the kind that has two strips of concrete just for your tires, plant more native plant gardens in your yard, reduce the overall amount of concrete on your property, plant rain gardens to collect rain water from your roof!
Why native plants?
Native plants are ideal for landscaping for many reasons. Because they have adapted Kentucky’s climate over millions of years, they don’t need chemicals to help them grow, they can tolerate our cold winters and hot summers winter, they have very deep roots which allow them to be more drought resistant, they have developed defenses against harmful native insects, and can serve as habitats for native wildlife (consider planting for butterflies, hummingbirds, or songbirds!). The deep roots of native plants also makes them ideal for rain gardens because they create channels in the soil which allow water to soak in quickly (see diagram below to compare the root depths of some native vs. non-native species).
Look on our website under Resources for the contact information for several native plant nurseries in central Kentucky.
Image used with permission from www.marc.org
What kinds of plants go in a rain garden?
Despite what you may think, rain gardens don’t have to be planted with water-loving plants! Since they drain so quickly (ideally 24-48 hours), the plants you put in only have to be able to tolerate lots of water for brief periods, but they also need to be able to withstand periods of drought. Different areas of your garden can be planted with different kinds of plants as well. For example, the berm won’t be receiving as much water as the low-lying middle, so arid plants (such as prickly pear, Kentucky’s native cactus) would do best there. If you’re not an experienced gardener or don’t have a lot of experience with native plants, just ask your local native plant nursery for suggestions. Remember to consider plant height, wildlife attraction, flowering, and sun/shade tolerance when choosing your plants.
What’s the difference in the function of a rain garden and a rain barrel?
Rain gardens and rain barrels essentially serve the same purpose which is reducing the amount of storm water that runs off of your property. A rain garden does this by capturing the water and allowing it to infiltrate the soil right there. A rain barrel on the other hand offers other options for how the water is used. Since rain water contains no chlorine, lime or calcium, and fewer sediments and dissolved salts than municipal water, it is perfect for watering vegetable gardens, raised planter beds and containers or indoor tropical plants like ferns and orchids. Rain water is perfect for automobile washing and cleaning household windows. Most rain barrels come equipped with faucets for attaching garden hoses. If you’re interested in buying a rain barrel, see www.kentuckyPRIDE.com for information on how to purchase one through a Lexington-based nonprofit!
Where else can I learn about rain gardens?
Wikipedia article - http://en.wikipedia.org/wiki/Rain_garden
Rain gardens in Kansas City - http://www.rainkc.com
Rain gardens in Michigan – http://www.raingardens.org
Rain Garden Network – http://www.raingardennetwork.com
Rain Garden design templates – http://www.lowimpactdevelopment.org/raingarden_design/templates.htm
Mill Creek Watershed Council (in northern Cincinnati) - http://www.millcreekwatershed.org/howto.pdf
Can I hire someone to build a rain garden in my yard?
Of course! If you’re interested in hiring someone to build your rain garden for you, consider referring to the Kentucky Nursery and Landscape Association at http://www.knla.org/membership.htm for the names of local landscape architect firms or looking in the Yellow Pages under Landscape Architects or Landscape Contractors. Remember that not all landscapers are experienced in building rain gardens so ask lots of questions to be sure you’re hiring someone who will build you a quality rain garden!
