A newly planted rain garden sits at the bottom of a low rise beneath a parking lot. A black iron fence surrounds the garden which is planted with native plants and grasses.
Nature Solutions A new rain garden and stormwater capturing green infrastructure at Knollwood Life Plan Community will capture an estimated 2.2 million gallons of runoff rainwater annually. © Matt Kane / TNC


Knollwood Life Plan Community Installs New Stormwater Capturing Rain Garden in Partnership with District Stormwater LLC

New rain garden will clean water before it enters Rock Creek and ultimately the Chesapeake Bay.

The Knollwood Life Plan Community and District Stormwater LLC—a wholly owned subsidiary of The Nature Conservancy (TNC)—announced today that construction has been completed on a new rain garden and stormwater capturing green infrastructure at the entrance of Knollwood. The new garden and infrastructure will capture an estimated 2.2 million gallons of runoff rainwater annually where it is cleaned before it reaches Rock Creek, the Potomac River, and ultimately, the Chesapeake Bay.

“As a non-profit life plan community, we are excited to be collaborating with District Stormwater, a subsidiary of The Nature Conservancy, and continue our commitment to preserve the environment,” said COL Paul Bricker, Knollwood COO. “This partnership continues to allow nature to thrive at Knollwood.”

“Billions of gallons of stormwater runoff and sewage flow into local rivers, and ultimately, the Chesapeake Bay, each year,” said Aileen Craig, Stormwater Retention Project Manager for TNC. “Through this project, Knollwood is further minimizing the stormwater pollution that flows into our waterways, and consequently damages water quality and aquatic habitat. Knollwood is demonstrating great leadership in D.C. through its efforts to improve the surrounding environment and the Chesapeake Bay for future generations.”

Directly adjacent to Rock Creek Park, Knollwood Life Plan Community sits on 16 acres in northwest Washington, DC and is home to 300 residents. The new rain garden is approximately 4,700 square feet in size and captures runoff from 1.6 acres of impervious surface. It includes a variety of native and flowering plants that will provide habitat and food for native wildlife, as well as being a new feature for residents and nearby neighbors to enjoy. Knollwood and District Stormwater are also planning to post interpretive signage along a nearby path explaining the project.

The green infrastructure was designed by the engineering firm Tetra Tech and built by Triangle Contracting LLC. The site will be maintained by Knollwood’s existing landscaping company, Ruppert Landscape. In addition, the DC-based nonprofit organization Casey Trees has planted over 50 new trees on site.

The project will also generate Stormwater Retention Credits (SRCs) to be sold on DC’s Stormwater Retention Credit market to real-estate developers who are unable to meet their own stormwater retention requirements on-site. Through its subsidiary District Stormwater LLC, The Nature Conservancy installs stormwater capturing green infrastructure sites around Washington, including a 14.5-acre project at Mount Olivet Cemetery that will soon add 4.9 additional acres through a third phase. Currently available credits can be purchased through the District Stormwater LLC website

Knollwood plans to host a ribbon-cutting ceremony for the project this fall. Photos of the new rain garden and stormwater infrastructure are available on nature.org.

The Nature Conservancy is a global conservation organization dedicated to conserving the lands and waters on which all life depends. Guided by science, we create innovative, on-the-ground solutions to our world’s toughest challenges so that nature and people can thrive together. We are tackling climate change, conserving lands, waters and oceans at an unprecedented scale, providing food and water sustainably and helping make cities more sustainable. Working in 76 countries and territories—37 by direct conservation impact and 39 through partners—we use a collaborative approach that engages local communities, governments, the private sector, and other partners. To learn more, visit www.nature.org or follow @nature_press on Twitter.