Build Your Own Rain Garden in PG County
What kind of gardens offer aesthetic beauty, but also positively impact the environment, especially our local waterways?
Not like other gardens, Rain gardens are designed to collect stormwater runoff and filter out water pollutants before they enter sewer drains or waterways. When it rains, water runs off impervious surfaces, such as roofs and driveways, and collects dirt, bacteria, chemicals, fertilizers, and other harmful pollutants which eventually flow into our local waterways. These Rain gardens are built with native plants, in shallow areas where drainage is possible.
Photo by Kathy LaLiberte
Rain gardens have become more widely used in urban planning as they are a cost-effective way to reduce runoff from urban areas and residential neighborhoods and help solve drainage problems. When it rains, 55 percent of the water due to impervious surfaces is unable to soak into the ground (McMahon, 2016). Many cities have extensive sewer systems to collect stormwater. However, the stormwater collected in cities goes directly into local waterways with little or no treatment. Prince George’s County (PG County), in Maryland has its share of stormwater runoff problems. PG County’s water flows directly into the Potomac River and Chesapeake Bay, a major estuary, so it is especially important to supervise and manage the water quality in this area. PG County also offers rebates for rain gardens. Continue on through this Story Map to learn more about the rebate programs, where rain gardens should be built, real life examples of active rain gardens in PG County and find the closest plant nursery to you to get started on building your own rain garden!
Rebate Programs
In PG County, rain gardens are eligible for rebate under the Rain Check Rebate program. Partnered with the Chesapeake Bay Trust, PG County offers incentives to residents and business owners for installing their own stormwater management practices like rain barrels, green roofs, cisterns, urban tree canopies, pavement removals, and rain gardens. The amount of rebate depends on each rain garden but up to $2,000 for residential rain gardens and $20,000 for commercial rain gardens can be recovered. In 2019, PG County approved up to 91 rain check rebate applications and gave away more than $73,000 in rebates.
Abstract
Rain gardens have become an effective method in urbanized areas for reducing storm runoff and improving water quality. Rain gardens should be built in areas at least ten feet away from major bodies of water or infrastructure, get decent sun exposure, have a relatively flat slope, and with sandy soils that get good drainage. This University of Maryland capstone project uses GIS techniques and software to create a suitability model that shows the area’s most and least suitable in PG County for rain gardens based off that criteria. This model uses a consist scale and weighted factors. Along with the suitability model, the Story Map features an interactive rain garden map that shows where current active rain gardens are located in PG County, and a plant nursery locator that finds the fastest routes to plant nurseries in PG County.
Where Should Rain Gardens Be Planted?
Rain gardens cannot just be planted anywhere. There are many factors that go into where one should plant a rain gardens and it takes a lot of thought and planning.
Data collected from Maryland’s GIS data catalog (2019)
Water/Infrastructure
Bodies of water and infrastructure is another component to be cautious of. A rain garden should also be at least 10 feet from any major body of water and infrastructure. This is especially important for rain gardens being built near residential homes. If the rain garden is too close to a home and starts to overflow, it could cause flooding in basements, crawlspaces, or any lower levels.
Data collected from FEMA (2019)
Sun Exposure
The location of a rain garden needs to get a decent amount of sun exposure. A rain garden in forested or shaded areas will not do as well. Ideally the rain garden should get a full day’s worth of sunlight. If that is not possible, at least a half a day of sunlight will work also.
Data collected from the National Land Cover Database (2020)
Slope
The slope of the ground will also affect where you should build a rain garden. The rain garden should be planted where the water gradually flows but does not pool or hold water for more than 24-36 hours to ensure drainage is occurring. Therefore, the slope should not exceed ten percent.
Data collected from ESRI (2021)
Soil
Lastly, a rain garden needs to be in an area that gets relatively good drainage. This can depend on the soil type. Soil most suitable for rain gardens should have a sandy or silty texture. Soils with clay will not drain as well or as efficiently.
Data collected from the National Resources Conservation Services (2019)
- Group A- High infiltration, well drained, sandy
- Group B- Moderate infiltration, well drained, coarse texture
- Group C- Moderate/low infiltration, fine to coarse like texture
- Group D- Slow infiltration, clay
- Group A/D- Slow infiltration, high drainage
- Group B/D- Slow infiltration, moderate drainage
- Group C/D- slow infiltration, slow drainage
Suitability Model
Through GIS techniques and software, a suitability model was created that shows areas most suitable (5) and least suitable (1) for rain gardens in PG County. The model used several datasets and layers that are scaled based off the criteria that it should be planted at least 10 feet from major bodies of water, areas with sun exposure, slopes less than 10 percent, and with soil that drains efficiently. Each factor in the model was weighted differently and different trials were performed to test different weights. After testing different scenarios with the weights, the model where slope was weighted the most and soil was weighted the least produced more areas suitable for rain gardens. Below is the final suitability model. Areas that hug Southeast D.C. are higher in suitability. This is a highly developed area with impervious surfaces and where multiple flood plains and flooding is located.
Suitability model created through GIS techniques that is set to a scale where 1 represents areas least suitable for rain gardens and where 5 represents area most suitable for rain gardens.
Photos from C-VILLE Weekly, Partnership for Water Sustainability, SUNY College of Environmental Science and Forestry
Check It Out For Yourself!
Rain Gardens in PG County
This is an interactive map that shows you where current rain gardens are located in PG County. Click on the rain garden icons to find addresses so you can visit these active rain gardens yourself. The rain garden icons also give more information about why the rain garden was built, its benefits to the environment, the plants that was used, and a picture of the rain garden.
Get started on building your own rain garden!
Click on the button above to find the fastest routes to various plant nurseries in PG County. This custom web application is designed to give you detailed directions to the closest plant nurseries from your current location. After determining the location for your rain garden, the next step is gathering your native plants! Native plants are recommended because they are adapted to the weather and climate of the area and will survive the best. Click here to learn more about Maryland’s native plants.
