Install a rain garden on your property to prevent stormwater from reaching the nearest storm drain or waterway.
What Is A Rain Garden?
A rain garden is a landscaped, shallow depression in your lawn designed to collect stormwater from your roof, driveway, or other impervious surface before it reaches the nearest storm drain or waterbody. By trapping stormwater and allowing it seep naturally into the ground, rain gardens minimize runoff and remove pollutants, reduce flooding, and help recharge groundwater supplies. In addition to their value in preventing stormwater pollution, rain gardens are typically planted with native shrubs or perennials, adding beauty to your lawn and providing habitat for birds, butterflies and beneficial insects.
Installing A Rain Garden: How Do I Get Started?
With proper guidance, rain gardens are not difficult to install and are easy to maintain. Rain gardens typically require digging a shallow depression, usually 6 inches deep, berming the edges to help keep water in and allow for proper infiltration, modest soil amendments, and planting with native perennials. There are numerous design guides, web sites, and even a (UCONN) Mobile Rain Garden App available with detailed instructions for installing a rain garden- including site assessment, sizing and design, installation, and plant selection guidance. We have listed a series of links to helpful web sites, factsheets, and presentations to help you design your garden in our Resources section, below.
In addition, the URI Cooperative Extension provides annual training opportunities for stormwater managers, natural resource professionals, volunteers and others interested in learning more about rain garden planning, implementation and maintenance. For more information and upcoming workshops, visit the RI Residential Rain Garden Program at the URI Outreach Center.
A properly designed rain garden should not be much different than maintaining any other garden on your property-weekly watering and weeding when the garden is first planted, followed by annual mulching, pruning, and replacing any dead or diseased plants. Rain gardens should also be inspected regularly for potential erosion problems and sediment accumulation.
Am I Required To Have A Rain Garden On My Property?
Rhode Island Stormwater Solutions is encouraging property owners to install rain gardens as a voluntary practice to help reduce stormwater pollution. However, new development or redevelopment projects may require a rain garden or some other type of Low Impact Development (LID) technique to manage stormwater. Rhode Island stormwater regulations enacted in 2011 require individual single-family residential development or redevelopment projects to treat the water quality volume, or one inch of stormwater runoff, from any new rooftop impervious surfaces of 600 square feet or greater in size and all new driveways and parking areas. The Rhode Island Department of Environmental Management (RIDEM) and the Rhode Island Coastal Resources Management Council (RI CRMC) have produced the guidance document Rhode Island Stormwater Management Guidance for Individual Single-Family Residential Lot Development to assist with designing, installing and maintaining stormwater management practices that meet the requirements for new or enlarged single-family dwellings, driveways and parking areas, including rain gardens.
For more information about managing stormwater at new development projects, visit the RIDEM Office of Water Resources.
Rain Gardens Are Not Bioretention
You may be familiar with the term bioretention as a stormwater management technique. Although rain gardens and bioretention basins function similarly, they are very different! Bioretention basins require detailed engineering, and are usually much larger with sophisticated conveyance devices (e.g., underdrains, overflow structures, etc.) and a prescribed soil mix to promote filtration by stormwater. Bioretention is often used when managing stormwater at new development projects or retrofits. Rain gardens are small in scale – ideal to manage runoff from smaller drainage areas such as residential rooftops and driveways – and utilize native, or modestly amended soils. Proper rain garden design may be achieved through appropriate site selection and simple sizing techniques.
For more information, please visit Small-Scale Bioretention Installation Training, a 2012 workshop sponsored by the U.S. Environmental Protection Agency, URI Cooperative Extension, City of Providence, and Groundwork Providence.
Resources And Materials
RI Residential Rain Garden Training Materials:
- Stormwater Pollution: A Big Problem with Backyard Solutions
- Rhode Island Stormwater Management Regulations
- Rain Garden Overview and Design
- Rain Garden Sizing Exercise
- Plant Selection and Care
- Rain Garden Installation
- Rain Garden Monitoring and Maintenance
- Site Assessment Checklist
- Soil Assessment
- Importance of Soil Texture
- RI Coastal Plant Guide / Example Plant List
- Rain Garden Maintenance: Residential
- Rain Garden Maintenance: Professional
Plant Pro Sejal Lanterman talks about installing rain gardens
NBC 10, April 2011
Manton Heights rain garden installation by Groundworks Providence,
EPA New England Greenscapes Program, April 2011.