Transforming Clark Hall’s Underutilized Nook to a Greener Landscape with Sustainable Benefits

March 24, 2017 • Sakib Ahmed

Clark Nook bioretentation area

The University of Virginia’s lush landscapes, teeming with local flora and fauna, have earned distinction as one of the most beautiful campuses in the United States. But these landscapes are more than just aesthetics; they also serve as valuable tools in helping the University meet its environmental obligations under the Clean Water Act.

UVA students planted a new spot of greenery with native grasses such as Juncus and Shenandoah Panicum behind Clark Hall in what is colloquially known as the Clark Nook. Organized by UVA’s Stormwater Working Group, the planting is part of a bioretention area that helps mitigate the environmental impacts of stormwater runoff.

“We wanted to turn a dead space into a functional landscape – and with student help, we were able to do that,” said Dawson Garrod, Civil Engineer for Facilities Management Environmental Resources.

The expansion of Clark Hall included a new sidewalk laid around the trunk of an old oak tree, around the side of the building. However, when the tree died, it left behind a patch of dirt and an oddly shaped sidewalk. Last summer UVA’s Grounds Improvements Fund approved funding to fix the oddity and create a bioretention area.

students planting grasses in the Clark Nook

The bioretention area provides the critical function of absorbing and purifying rainwater runoff to prevent erosion and contaminated water. The purification process starts with the permeable stone paving. The stone paving slows down the water coming from downspouts on the adjacent wall; this is a significant step in ensuring that larger sediments separate from the water before it enters the planted area.

Once the larger sediments separate out, the water flows through the specially designed bioretention area to remove pollutants and complete the last stage of filtration through vegetation and soil before returning to the water table. The plants in the bioretention area absorb pollutants out of the water, such as phosphorus and nitrogen. The last phase of filtration begins in the engineered soil, which contains multiple layers of mulch, filter fabric, gravel-pea, and large stone. As the water passes through each layer, harmful pollutants such as reactive nitrogen are filtered out. This process can reduce the level of nitrogen in the water by over 60%, which helps with UVA’s nitrogen reduction goals.

volunteers helped plant grass in the Clark Nook bioretention

UVA’s Sustainability Plan outlines a goal to reduce reactive nitrogen losses to the environment 25% below 2010 levels by 2020. Projects such as the Clark Nook are an important part of meeting that goal.

The pollutant reductions achieved from this project will serve as a credit in UVA’s annual stormwater reporting to the Virginia Department of Environmental Quality (DEQ), which regulates the amount of stormwater runoff on Grounds and tracks the Commonwealth’s compliance with Clean Water Act requirements.

“This bioretention project was all non-required development, a project that the University and students felt was essential to good stewardship of our environment, and all reductions achieved will be a 100% credit in our DEQ reports,” said Garrod.

Giving students the opportunity to help build the bioretention area is an important part of the University’s mission to provide hands-on learning, in the context of the campus living-learning model. According to Garrod, many of the students who participated in the project were environmental science majors who had in-depth knowledge about bioretention systems but had never built one themselves.

“These students benefited from seeing the connection between what they are studying in the classroom and a real world application of those concepts. On the Facilities side, we benefited from having these students, because it allowed us to get this project completed quickly,” said Garrod.

To learn more about the Stormwater Working Group, and get involved with these projects, visit their website.