Remove Pollutants with a Rain Garden
Gardeners as well as city planners consider the rain garden to be the next great gardening practice that will define a landscape as being both beautiful and water-wise.
What is a rain garden? Simply put, a rain garden is designed to capture rainfall as it flows in a runoff through your yard, then stores that water in its roots for nourishment, thus intercepting and removing pollutants (fertilizers, pesticides, soil, oil, grease, even feces and urine) before returning it to the water cycle.
A well-functioning rain garden is quite effective in preventing runoff, and in capturing and removing many pollutants. Metals such as zinc, copper, and lead can be absorbed by plants and filtered through the organic matter in the soil of your rain garden, removing at least 40% and up to 97% of these metals in runoff. Rain gardens can also remove up to 87% of the phosphorus and 15-92% of the nitrogen contained in runoff (Source: U.S. EPA report on National Pollutant Discharge Elimination System storm water program).
Getting Started
Rain gardens are fairly easy and inexpensive to create. They have a defined structure made up of five basic components.
1. Create a depression by berming a sloped area or digging down three to six inches and piling soil around the edges. Take care of heavy, frequent rains by preparing an overflow area to direct excess water away.
2. Soil mix (aka filter bed) properly amended and designed with both coarse-textured particles that allow water to enter the soil, and finer-textured particles that hold the water for plant use.
3. Organic matter is critical to all garden soils ~ mulch, or compost. Not only does organic matter increase the soil’s ability to absorb and drain water, it also fosters the proliferaton of microscopic organisms and earthworms that are vital to healthy soil and its ability to support plant growth and remove pollutants.
4. Plant selection should include woody trees and shrubs, and a selection of perennials to provide the filtration needed in a rain garden.
5. Rock your garden to slow the water’s velocity or create swales that allow water to collect and enter the soil. Make sure your rocks are large enough not to wash away during a storm.
A great reference book to get you started on your own ecologically designed garden is available in bookstores now ~ Rain Gardening in the South: Ecologically Designed Gardens for Droughts, Deluge, and Everything in Between by Helen Kraus and Anne Spafford (Eno Publishers,$19.95)
Topic: Green House, Live Green Picks Tags: perennials, plants, pollutants
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