Browns Creek is a backyard favorite of many Nashvillians. It flows through parts of Green Hills, past the Nashville Fairgrounds, past Trevecca Nazarene University, and through the downtown warehouse district before emptying into the Cumberland River. Urban and suburban development can wreak havoc on local streams like Browns Creek, resulting in what scientists refer to as “urban stream syndrome”: pollution, erosion, and habitat degradation. The project included five major components: bank stabilization, riparian buffer planting, depaving, rain gardens, and community engagement. Ongoing urban waters initiatives in the Brown’s Creek watershed continue today thanks to generous support from Oracle.
STREAM BANK STABILIZATION AND RIPARIAN BUFFER PLANTING
Many factors can cause erosion in streams, including construction, clearing plants or mowing to the stream’s edge, and damage from livestock access. Often, clearing vegetation from a stream bank or allowing livestock unrestricted access to a stream can cause the stream banks to erode. When this happens, the stream banks must be stabilized to halt erosion and prevent dirt from entering the stream.
As part of this project, the Compact stabilized stream banks at several locations along Browns Creek using a technique known as bioengineering, which is an environmentally friendly way to stabilize stream banks using biodegradable materials and native plants.
One bioengineering technique uses what are known as coir revetments, which are cedar trees wrapped in coconut fiber nets to create a giant porous structure in the shape of a burrito. These revetments are anchored into the bank with wire and protect the bank from the force of high flows; they also trap sediment within the revetment itself, which over time fills with sediment until it rebuilds the bank where it had once been eroded.
A second bioengineering technique uses that same biodegradable coconut fiber net to protect the bank from erosion by covering the areas lacking vegetation. This net is anchored by hammering in live stakes, 2-foot long cuttings of willow, dogwood, buttonbush, and other certain species to hold it in place. These live stakes sprout leaves and roots that help protect the bank from the force of high flows, and the roots anchor the soil in place as they grow. Prior to installing this net and live stakes, the Compact made the steep, eroding bank less steep by reshaping the bank with shovels and hand tools, which allows the water during high flows to slow down and spread out rather than hitting the steep bank and causing more erosion.
Bank stabilization bioengineering is a good quick fix, but in order to ensure long-term stability, the Compact recommends also restoring a creek’s riparian buffer in addition to bank stabilization. A riparian buffer is a strip of trees and shrubs along a stream’s banks whose roots help hold the soil in place. In addition to preventing erosion, planting trees on streambanks shades the stream and provides wildlife habitats for both land and aquatic dwelling animals. As part of this grant, the Compact planted a riparian buffer along the West Fork Browns Creek near 4403 – 4405 Scenic Dr, Nashville, TN 37204.
DEPAVE
In order to plant even more trees near Browns Creek and reduce the amount of polluted runoff flowing into it from paved surfaces, the Compact depaved over 18,000 square feet of an unused parking lot across from the Nashville Fairgrounds in collaboration with Metro Water Services.
Over a hundred volunteers from the community and the Holy Family Catholic Church came out to help remove chunks of asphalt with pry bars, shovels, and pickaxes. The assortment of large native trees planted there contributed to the Root Nashville campaign’s goal of planting 500,000 trees in Davidson County by 2050.
The parking lot’s proximity to the creek placed it in a FEMA floodway, meaning it wouldn’t have been able to be used for future development purposes. As a paved lot, it couldn’t absorb any water when it rained; instead, all of the water that fell on it accumulated pollutants and litter as it flowed over the asphalt’s surface and downhill into Brown’s Creek.
Depaving transformed the lot from an impervious expanse that contributed to pollution and flash flooding into a forested, absorbent green space, which will protect the creek and the people who live by it.
In 2024, the site was featured on News Channel 5 as an example of how depave projects can increase green space and cool cities.
RAIN GARDENS
The Compact worked with Glendale Baptist Church, which is located near the creek, to install two large rain gardens on church property to capture stormwater runoff from the parking lot and roof. These gardens feature visually appealing native wildflowers and grasses whose deep, complex root systems are able to absorb much more water than standard turf grass.
The Compact also installed five dog waste bag stations along a walkway near the rain gardens. Pet waste left on the ground contributes to pathogen levels in local streams, and picking up waste is one of the easiest ways for people to protect local waterways in everyday life.
COMMUNITY ENGAGEMENT
To help the community get involved in the Browns Creek restoration projects, the Compact also hosted two virtual educational talks and one in person walk-and-talk at the creek. At these events, Compact staff discussed aquatic ecosystems, urban pollution sources, and common stream restoration practices with interested locals including a group of Lipscomb Academy High School students. The Compact also led three volunteer stream cleanups to remove trash from the banks of Browns Creek.
IN SUMMARY
The Browns Creek restoration and depave project made significant strides toward improving the health of the local waterway, employing many different research-backed techniques to reduce pollution, prevent future degradation, and increase awareness. The Compact hopes to see Browns Creek remain beautiful for many future generations of people and wildlife living alongside it.
