This summer, 20 volunteers from Healthy Harbor, Constellation, Baltimore City Youthworks, and the Chesapeake Bay Foundation banded together to install The Harris Creek Rain Garden. Funded by the Baltimore City Department of Public Works and the Chesapeake Bay Trust, this garden sits at the lowest end of the Harris Creek Watershed. The rain garden was engineered to naturally filter and control flooding by redirecting rainwater through flower basins. Spanning from Clifton Park to Canton, Harris Creek runs through a storm drain system under 17 neighborhoods that comprise the Harris Creek Watershed in East Baltimore.
As a rainstorm wages on, pollutants and sediment like dirt, fertilizer, chemicals, oil, and bacteria collect into water runoff. Composed of three connected pools that water runoff from Boston Street, the rain garden will help improve the water quality of the Harbor and storm sewer system, inherently preventing water pollution and flooding as well as erosion.
The sloped area that the rain garden lives in, is the new home of native shrubs, perennials, and flowers. Unlike a typical lawn or garden, these layers of specifically designed vegetation and soil serve one of the main goals of the rain garden: simply to improve water quality. Of the over 850 plants utilized in the rain garden, all of the greenery and flora implemented thrive in the natural habitat of the water basin native to the area. These rain garden perennials include plants like the Blazing Star and the state flower, the Black Eyed Susan. Every plant was hand selected because their roots are fundamentally capable of tolerating wet environments.
Known as “wet feet” plants, the plants in the flower basins are water tolerant, with deep roots that add extra outlets for stormater to filter into the ground. They draw in nutrients from the water they’re absorbing, and their complex root systems help to break down what’s washed along in the water runoff, including some of those pollutants.
“Plants were selected from a native plant palette based upon the qualities of the existing soils, goals and objectives expressed by the community, Waterfront Partnership, and Baltimore City Recreation and Parks and general hardiness,” says JoAnn Trach Tongson of Mahan Rykiel the landscape architecture, urban design, and planning firm that worked on the rain garden. “We created a list of plants with desirable traits based upon client and community feedback and refined the list ultimately installed with those that require less maintenance while aesthetically pleasing throughout the various season.”
Along with filtrating pollutants, these plants are also pollinator habitats. This means that not only does the rain garden ultimately protect the Harbor against pollutants, it also provides a home for other wildlife, like birds and bees, serves as a windbreak, and helps stabilize the soil. Pollinators have two basic habitat needs: a diversity of flowering native plants (like the ones living in the flower basins of the rain garden), and egg-laying or nesting sites. So while the rain garden filters water and manages flooding, it’s also creating a new habitat for the environment’s much needed pollinators.
But how these plants hold up against all these pollutants is nature putting in some amazing work. “Some of the most harmful pollutants to the Chesapeake Bay are nitrogen and phosphorous, which come from excessive use of fertilizer and from sewage leaks or overflows,” Tiffany Kim, a Program Manager at Healthy Harbor explains. “Our plants in the rain garden are happy to use the nitrogen and phosphorous in stormwater runoff for their own growth instead of letting it all wash out to the bay.”
The soil that the rain garden helps to stabilize also plays a significant role in cleaning water before reaching the Harbor, “A large part of the rain garden’s filtration capability is also performed by the depth and type of soil used. Simply having runoff pool on top of and percolate through that soil will result in significantly cleaner water when it reaches the Harbor, “Kim explains.
A week after installation the rain garden was put to the test and endured the first 100 year storm (a storm with a 1% or a 1-in-a-100 chance of occurring in any given year) it was designed to filtrate. After holding up throughout the storm
While the Harris Creek Rain Garden is the only big restoration project in the area, it came to fruition only after learning from other rainwater renovation projects like Library Square.
“It’s much easier to find funds for the installation of an exciting new project than for its upkeep,” Kim explains. “That’s why we’re depending on our amazing volunteers to help us take care of the garden every month by weeding, mulching, watering, picking up trash, and replanting as necessary.”
With one of the main challenges of the rain garden simply being maintenance — so with such great benefits, the rain garden also comes with its challenges, making this project one that was completed this year, but will continue to improve water quality and engage volunteers for years to come.