Suffolk County Government Crest

Suffolk County Stormwater Management Program

Edward P. Romaine, County Executive

Department of Public Works

Department of Economic Development and Planning

What is Smart Growth?

Smart growth refers to development strategies that revitalize neighborhoods, protect farmland and open space, keep housing affordable, reduce urban sprawl, and provide more transportation choices. Strategies that promote smart growth include reducing impervious surfaces, restricting development in environmentally sensitive areas, and using environmentally friendly green infrastructure.

Why is smart growth needed?

In recent U.S. history, urban and suburban communities have expanded rapidly into farmland and forested areas. Over the past two decades, the rate of land development has been two times greater than the rate of population growth. Between 1982 and 1997, U.S. population increased by 15% and developed land increased by 34% (Pew Ocean Commission, 2002). At this rate of growth, an additional 68 million acres in urban and suburban development will occur from 2000-2025.

This is significant because when natural vegetation is replaced with impervious surfaces; stormwater runoff increases and wildlife habitat and natural areas are lost. As the percentage of impervious surface increases, the volume of stormwater runoff increases, thus contributing more pollutants to local waterbodies. The end result is poor water quality in many water bodies.

Smart growth promotes greater mixing of housing, commercial and retail uses. This makes the community more transit and pedestrian friendly.

Green Infrastructure

Green infrastructure is utilized in smart growth to provide water quality protection. Green infrastructure is a comprehensive approach to water quality protection that uses trees and other vegetation to manage and treat precipitation naturally rather than collecting it in pipes and discharging it to surface waters. Green infrastructure uses engineered systems such as:

  • Green Roofs
  • Rain Gardens
  • Vegetated Swales
  • Rain Barrels

Smart growth conserves resources by reinvesting in existing infrastrucutre and reclaiming historic buildings.

Rain Gardens

What is a Rain Garden?

Rain Gardens are shallow depressions dug in a lawn and planted with native plants and flowers. Rainwater from a building's roof is directed into a rain garden. The rain water slowly percolates into the ground instead of creating stormwater runoff. Compared with conventional lawns, a rain garden recharges 30% more water into an aquifer. This is especially important here in Suffolk County, because we rely on one aquifer for our water supply.

Rain gardens come in all sorts of shapes and sizes. Many types of grasses, shrubs, common flowers and even trees can be used. Native plants and perennial flowers are recommended for rain gardens. Mulch is also important in pollution removal, maintaining soil moisture, weed control and erosion prevention. You can also incorporate a rain barrel and direct the overflow water into your rain garden.

Rain gardens are inexpensive, but do require some labor in preparing the site and some minor weeding during the first year. You can always start small and expand your rain garden in the future.

Why are Rain Gardens important?

Rain gardens reduce stormwater pollution from entering our local bodies of water. The U.S. Environmental Protection Agency (EPA) reports that stormwater pollution is the number one source of water pollution in the U.S.

Rain gardens increase the amount of water that recharges local aquifers. Here in Suffolk County, we all rely on groundwater as a water source in our homes and businesses.

Rain gardens help prevent road flooding and flooding in poor drainage areas by reducing the water runoff volume.

Rain gardens enhance the beauty and value of your property. Plants can provide habitat for birds and food sources for butterflies.

Rain gardens help prevent pollutants from your yard and driveway from entering our local water bodies. A recent two year study conducted at the University of Connecticut concluded that rain gardens remove pollutants from water especially nitrogen.

Size and Location?

So where do you place your rain garden and how big do you make it? How deep do you dig and what about soils and slope? The following section will answer these questions and others to get you started.

A rain garden should be at least 10 feet from a building so water is directed away from the building foundation.

Plan your rain garden close to a downspout. The downspout can be directed towards the rain garden so water flows directly into the rain garden.

Do not place a rain garden over a septic system, locate rain garden at least 25 feet from septic system.

If you have a water well, build the rain garden at least 25 feet away from the well head.

It is better to place a rain garden in an area that receives full sun or partial sun instead of under a tree. This is because the sun will provide a better evaporation rate after a heavy rain and digging will be easier without damaging tree roots.

Rain gardens are easier to create on flat ground, rather than on a moderate or steep slope.

Do not build your rain garden in an area that has standing water after a rain event. This could indicate that the soil in this area does not allow water to readily infiltrate into the ground. You want to make sure your rain garden is in an area that has good water infiltration.

Make sure there are no underground wires (electrical, phone, TV or cable) before you start digging.

Pick a location that is convenient for you and integrated into your existing landscaping. A rain garden next to a patio adds color and an opportunity for you to sit and enjoy your garden.

Rain gardens with crescent, kidney and teardrop shapes create pleasing visual affects.

Rain gardens work best on sandy soils. Here on Long Island our sandy soils are ideal for rain gardens!

What should I plant in my Rain Garden?

Rain gardens are typically planted with native plants. Native plants are recommended for a number of reasons. Native plants are easier to grow and are adapted to local weather conditions including temperature and precipitation patterns, thus allowing them to live through droughts and downpours and the heat of the summer and cold of the winter. Once your native plants are established they will thrive without additional watering or fertilizers.They are also resistant to most pests and diseases. Due to these characteristics, planting with natives SAVES YOU MONEY!

Additional benefits of native plants is that they rarely become invasive and take over your garden/landscape. Native plants provide food and shelter for birds, butterflies and other desirable wildlife. They also help to improve and protect local water quality. Their deep root systems increase the ability of soil to hold water, thus reducing stormwater runoff and erosion.

It is important to know that if you choose to plant native plants, you should not plant non-native plants along with the natives. Many non-native plants will compete with the natives for essential resources such as food, water, space, and light and can out compete native plants.

Please click here and scroll down to "List of Native Plant Species in Long Island" for a list of vegetation native to Long Island. There are separate lists for Suffolk and Nassau Counties.

Buying native vegetation on Long Island

The Long Island Native Grass Initiave (LINGI), pioneered by the Suffolk County Soil and Water Conservation District, sells 26 species of native grasses, flowering plants, and shrubs. All plants are produced from seed collected from native plan populations across Long Island and Staten Island. They hold native plant sales, usually in June each year.

A document titled "Long Island and NYC Metro Area Native Plant Resources for Restoration and Landscape Plantings" was recently completed by the USDA Natural Resources Conservation Service, Suffolk County Soil and Water Conservation District, and the Greenbelt Native Plant Center. Some of the topics covered include: field and taxonomic guides, gardening books, nurseries and seed producers, and organizations and projects of interest.

Frequently Asked Questions

Do rain gardens create standing water and breed mosquitoes?

No, a properly designed rain garden will be dry between rainfalls. Standing water will only last for a few hours after a rain storm. Mosquitoes need longer periods of standing water and will more likely breed in bird baths or other open containers that hold water.

Do rain gardens require a lot of maintenance or expense?

Some weeding and watering may be required in the first two years. This does not have to be costly. The labor can be provided by you and your family and the main cost will be for plants and flowers.

What is a berm?

A berm is a simple soil wall on the down slope side of the rain garden. If your rain garden is located on a slope, flowing water entering a rain garden will continue flowing down slope. A berm is needed to keep water in the rain garden so it can soak into the ground.

How can I make my rain garden special?

You can enhance a rain garden by using stones, ornamental fences, garden benches, birth baths, bird feeders, or other attractive outdoor decorations.

A rain garden can be an attractive landscaped flower garden, where only you know its pollution prevention purpose. But please share your secret with your neighbors! Encourage and help them to add their own rain garden to their yard and reduce even more stormwater pollution in your neighborhood.

* A great example of how a finished rain garden looks in a commercial location, check out the Griffing Avenue Rain Garden located at Cornell Cooperative Extension of Suffolk County's rear parking lot!