Over the years, we’ve seen the damage excess stormwater can do to our parks and streams, and to infrastructure including trails, roads and our Metro system, so whenever we hear about new and local mitigation efforts… let’s just say our ears perk up.
Knollwood, the independent and assisted living community for seniors who have served in government and in the military, counts Rock Creek Park among its neighbors in Chevy Chase. And, Knollwood recently did its wild neighbor a favor. Over the summer, it announced the completion of new stormwater control infrastructure next to its parking lot.

Last spring, before the Knollwood rain garden’s installation. (photos courtesy of Knollwood)

And after.
We asked Knollwood to tell us more about the project.
The Knollwood Life Plan Community and District Stormwater LLC, a wholly owned subsidiary of The Nature Conservancy, has completed work on a new rain garden and stormwater pond that borders Tennyson Street NW. The new garden and pond will capture an estimated 2.2 million gallons of rainwater runoff annually, to clean it before it reaches Rock Creek, the Potomac River, and ultimately the Chesapeake Bay.
Paul Bricker, Knollwood COO, says the partnership with District Stormwater is important to ADF [Knollwood’s nonprofit owner] and Knollwood, which was founded in Northwest Washington, DC 60 years ago, because of the life plan community’s commitment to reducing its impact on the environment.
“We are elated to be collaborating with District Stormwater as we take another step to preserve the environment,” said Bricker.
“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 The Nature Conservancy. “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 DC through its efforts to improve the surrounding environment and the Chesapeake Bay for future generations.”
The rain garden is approximately 4,700 square feet in size and captures runoff from 1.6 acres of impervious surface. It has a variety of native and flowering plants that will provide habitat and food for pollinators and is a nice outdoor feature for residents and neighbors to enjoy.
Ward 3 DC Council member Mary M. Cheh, a supporter of environmental legislation on topics such as pesticide protection praised the stormwater project.
“The Knollwood Life Plan Community’s new rain garden is an outstanding example of environmental stewardship in a residential setting,” said Council member Cheh. “By retrofitting their existing space with green infrastructure, Knollwood will be able to divert millions of gallons of storm water runoff each year. Undoubtedly, this project will inspire neighbors and other nearby communities who are similarly looking to contribute to cleaner local waterways and a healthier Rock Creek Park.”
To educate and inform residents and neighbors about the benefits of the stormwater project, educational signage about the benefits of the pond, will be installed. In addition, the DC-based nonprofit organization Casey Trees has planted over 50 new trees on site. 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 landscaping company, Ruppert Landscape.
Knollwood leadership is hopeful that the rain garden project will inspire nearby residents and communities to also contribute to the greater effort of improving local waterways in the region.