Rain gardens

OvERVIEW

Rain gardens are small, shallow, human-made depressions in the ground used to capture stormwater (rainfall not absorbed by the ground) and improve water quality. Government studies have shown that up to 70% of the pollution in our streams, rivers and lakes is carried there by stormwater. If strategically placed on a schoolyard, a rain garden can store and filter the site’s stormwater and significantly improve the quality of water entering local waterways. Creating a rain garden will help students to see the connection between stormwater in their community and the health of the Chesapeake Bay Watershed.

Rain gardens are filled with mulch and sandy soil, which absorb huge amounts of rain and help to capture materials that wash off impervious surfaces such as roofs, roads and parking lots. They mimics the natural cycle of water through forests; In nature leaves that line the forest floor soak up water during heavy rain storms and allow it to slowly penetrate the soil. In addition to removing common pollutants from stormwater, rain gardens are also attractive landscape features. Plant gardens with diverse and attractive vegetation to attract butterflies, bees and other wildlife.

Time

Depending on the type of rain garden selected, installing a rain garden can take anywhere from a month to a year. The simplest approach to creating a rain garden is to install it in an area where water normally ponds. Choosing to build a rain garden that collects runoff from your school roof or parking lot will require more engineering and special permitting and will increase the length of your project, yet it will have a larger impact on runoff reduction. During the first year of establishment, watering and weeding will be required. Once the rain garden is established, limited watering and some continued weeding is needed.

land use

The amount of land needed will depended on the amount of runoff you are hoping to capture. Even if you do not build a large rain garden, placing your garden in a location where stormwater usually pools can be very effective.

Materials

Building a rain garden requires porous soil, sand, mulch, native plants, and gardening tools such as shovels, rakes, pick axes and gloves. Other materials such as drains and wood might be needed depending on the type of rain garden chosen.
For a more detailed list of materials visit the Virginia Department of Education.

EDUCATIONAL THEMES

Water quality, local waterways and the Chesapeake Bay, impervious and pervious surfaces, stormwater runoff, water pollution, native plants and wildlife

Additional resources

Chesapeake Bay Foundation: Build Your Own Rain Garden

Virginia Department of Education: Resources for Building a Rain Garden

Virginia Department of Forestry: Rain Gardens

Rain Gardens of West Michigan: Beautiful Solutions for Water Pollution

University of Wisconson, Extension and Wisconson Department of Natural Resources: Rain Gardens (PDF)