Restored Rivanna River tributary sets the stage for a new botanical garden

On a sunny November morning, a team of researchers heads down to a stream in Charlottesville, Virginia to look for bugs in the water. 

The outing is led by the Rivanna Conservation Alliance (RCA), a nonprofit organization that’s been conducting biological monitoring in the stream since 2021. During biological monitoring, RCA documents larval-stage insects and other small aquatic organisms known as benthic macroinvertebrates. The organisms are food for fish like shad and trout, and can help determine how clean the water is since certain species only survive in high-quality conditions. 

“Depending on what we find, and how many we find, it gives us an accurate representation of stream health,” said Claire Sanderson, RCA’s director of monitoring. 

Years ago, this same tributary of the Schenks Branch was in extreme disrepair, with steep banks that were so eroded it made it difficult to get down to the water to take samples. Roughly 436,000 pounds of sediment were flowing downstream due to the erosion, entering waterways already listed as impaired by the Virginia Department of Environmental Quality (DEQ). The Schenks Branch tributary sits within the historic Rivanna River watershed, which drains to the James River and the Chesapeake Bay. 

In 2023, the city officially broke ground on the stream’s restoration using funding from Virginia DEQ. Following plans developed by the firm Hazen and Sawyer, the contractor, KBS Earthworks, reworked roughly 840 linear feet of the waterway to include a more natural flow and healthier, more protected banks. Next, the city worked with the firm Waterstreet Studio and other local partners to improve the land surrounding the tributary—planting 147 mature trees, 578 shrubs, 698 native plants and 696 juvenile trees. 

“The site has been transformed from a degraded landscape, with a stream plagued by excessive erosion, poor habitat and a valley overrun with invasive plant species to a healthy and thriving native ecosystem,” said Dan Frisbee, water resources specialist with the City of Charlottesville.

A key partner in all of this was the Botanical Garden of the Piedmont, an organization developing a 15-acre botanical garden around the area. The Schenks Branch tributary runs directly through the botanical garden and will be a centerpiece of the green space, once construction starts on the space in 2026.

“The stream restoration is the first step in developing the garden,” said Bruce Gatling-Austin, educational coordinator at Botanical Garden of the Piedmont.

With this restoration, an estimated 160 pounds of nitrogen, 145 pounds of phosphorus and 172,000 pounds of sediment will be reduced annually. However, as the stream recovers, it’ll also be important to measure the return of benthic life. 

Throughout the restoration, RCA has been taking benthic samples to set a baseline health score for the stream. The organization's biological monitoring program is certified as Level 3 (the highest scientific level) by Virginia DEQ, which means their data can be used in the state’s official water quality reporting. They conduct long term biological monitoring at 50 sites in the Rivanna River watershed, gathering about 100 samples a year. 

During their fall 2024 outing at the Schenks Branch tributary, RCA recorded a relatively low score for the tributary—a 19.32 out of 100. This was due in part to a low diversity of macroinvertebrates recorded: mostly midges and common caddisflies, which can survive in low water quality conditions. 

However, this does not mean the stream restoration didn’t work. Tributaries can take years to recover after restoration has been completed. The vegetation planted around the waterway takes time to grow in and the underground stream bed has to recover from years of degradation.

“It's still early days,” said Sanderson.