Rain Gardens

Capturing Rain to Help Our Environment

Developing and implementing sustainable solutions for public spaces is a priority for the Golden Triangle BID. Like many downtown areas, Washington’s central business district is mostly comprised of impervious surfaces like roads, sidewalks, and rooftops.

When it rains, these hardscapes don’t allow that water to infiltrate into the ground as natural landscapes like forests or meadows would. Instead, torrents of stormwater flow from these surfaces into our storm drains, carrying pollution like trash and car oil to Rock Creek and the Potomac River.

To help clean up our local streams and rivers, we are helping to divert tens of thousands of gallons of polluted stormwater from sidewalks and streets into rain gardens, where it is filtered by plants and specially engineered soils.

Rain Gardens in the Golden Triangle

Since 2012, we have built 19 rain gardens around the neighborhood and converted 13,000 square feet of asphalt and concrete to green space. This includes the installation of a rain garden at the Rhode Island and M Street island in 2012, a sustainable rainwater harvesting system in Duke Ellington Park in 2017, and 17 (and counting) rain gardens on 19th Street. These projects have been completed with funding from DC’s Department of Energy & Environment and the Environmental Protection Agency.

Four rain gardens located at the corners of 19th and L Streets are recognized as Certified Wildlife Habitat™ by the National Wildlife Federation. Adding to the beauty of the rain gardens between M and K Streets on 19th Street are seven public art sculptures created by artist Foon Sham.

Our dedication to this project helped us achieve LEED Platinum, the highest level of LEED certification, from the U.S. Green Building Council. We’re the first BID in the world to be certified through the LEED for Communities program.

The Greening of 19th Street

In 2019, we built 11 new rain gardens and 10 expanded tree boxes along both sides of 19th Street between K and M Streets. This project, which added more than 4,500 square feet of green space lining two full blocks of the most vibrant corridors in the central business district, earned us the top award in the planning, design, and infrastructure category for the International Downtown Association in 2020.

In 2021, we continued expanding our 19th Street rain gardens, adding two more gardens with almost 1,200 square feet of permeable surface and the ability to retain nearly 4,900 gallons of rainwater per storm. These rain gardens have been completed between Pennsylvania Avenue and I Street and include natural granite seating as well as pollinator-friendly plants.

The benefits to a project of this scale are numerous:

  • The rain gardens can capture and filter almost 48,000 gallons of polluted runoff per storm. This reduces the risk of local flooding and helps clean up our waterways. Recent storms have shown the advantages of the rain gardens.
  • Several trees planted as a part of the project provide cooling shade to the sidewalks, lowering the area’s heat island effect. They also help filter out harmful air pollution and mitigate traffic noise.
  • Hundreds of new native plants in the gardens provide an additional corridor of much-needed habitat for pollinators, such as bees and butterflies.
  • These 5,700 square feet of green space may help improve the mental and physical well-being of the thousands of pedestrians that pass by each day. People are happier around trees!

A Unique Public-Private Partnership

All rain garden projects in the central business district are made possible through a partnership between the Golden Triangle BID and the DC Department of Energy & Environment with funding from EPA. Support for the 19th Rain Gardens project is also provided by Pepco – An Exelon Company, Rockrose, The Tower Companies, Carr Properties, OTO Development, Wawa, and Population Services International.

How Do Rain Gardens Work?

Rain gardens are built lower than the neighboring road or sidewalk and are carefully graded to form a slight depression. This allows them to capture and hold stormwater runoff, which flows in from the street via curb cuts. The water then soaks into the ground instead of pouring into storm drains and eventually the Potomac River or Rock Creek. Plants in the rain garden are specially selected for their ability to both absorb lots of water and survive long dry periods between storms. Soil, mulch, and stones also channel and filter water during storms before releasing it slowly into the ground.