A P3 Payoff

What does “yes” look like? Chattanooga City Councilwoman Carol Berz posed this question many times over the last five years as she pushed for the renaissance of Chattanooga’s Brainerd Road community.

For years, three vacant car dealerships rotted away along the roadway, near the Chattanooga Metropolitan Airport’s runway protection zone. The deteriorating buildings were a source of concern for local businesses, residents and city government officials, but commercial developers expressed little interest in purchasing the land and revitalizing the area.

Berz finally found an answer in a $4.5 million improvement project, where a public-private partnership (P3) transformed the 8-acre, decaying urban landscape into a rolling field of prairie grass and native plantings sprinkled with public walkways.

“When the airport and the city came together, this project took life. That’s when we learned what ‘yes’ looks like,” says Pete Yakimowich, Arcadis’ national discipline leader for green infrastructure.

The senior consultant for Arcadis, a U.S. firm that provides consultancy, design, engineering and management services worldwide, says the Jay Hollingsworth Speas Airport Award winning project is a keystone effort that is part of a larger venture to revitalize the Midtown Area, which he characterizes as a “diamond in the rough that’s gotten a little tarnished over the years.”

“This venture helped kick off that effort,” he says. “It’s a great demonstration project for future public-private partnerships.”

 

Communication

“An airport is here to serve the community,” says Terry Hart, president of the Chattanooga Metropolitan Airport Authority (CMAA). But serving the community is impossible without communication. Hart believes in regularly attending city meetings and networking with community members. Without these relationships, he believes the cooperative stormwater project may not have taken off.

The property along Brainerd Road, with its vacant Volvo, Infiniti and BMW dealerships, sorely needed some TLC. Initially the airport sought FAA funding to purchase the land, demolish the abandoned buildings and plant grass on the razed site. However, the goals expanded when Hart learned of the city’s plans for a water quality project in the same area.

Due to legacy problems with its National Pollutant Discharge Elimination System permit with the EPA, the City of Chattanooga had agreed to a supplemental environmental project in the Midtown Area, according to Don Green, Chattanooga’s water quality supervisor. When the city sought stakeholder support for this effort, the CMAA stepped up. “We thought instead of just planting grass why not do something that would also help the city with stormwater,” Hart says.

They partnered to tackle the area’s flooding problem and stormwater challenges in a collaborative effort that has since become a National Water Quality Demonstration Project. The work demonstrates how green infrastructure may be used to divert stormwater runoff and prevent it from entering a city’s stormwater sewer system.

Yakimowich characterizes the project as a perfect storm. “You had the city needing a supplemental environmental project for compliance purposes; an airport looking to facilitate its long-range plans; and a community seeking to revitalize and reinvigorate the area,” he says. “This truly was a team effort.”

 

Collaboration

All in, the project bolsters airport safety by extending the landlocked airport’s runway protection zone. An FAA grant covered all but 10 percent of the project’s price tag, with the CMAA laying down the rest.

The airport paid $3.69 million to purchase the property and spent more than $670,000 razing the buildings. Workers salvaged, repurposed and reused construction waste. A machine crushed concrete on site, recyclers picked up usable metals and other materials, and crews stockpiled soil removed from the area for later use, netting an Tennessee Governor’s Environmental Stewardship Award for Excellence in Sustainable Performances.

“The concrete buildings were rubbelized,” says John Naylor, CMAA vice president of planning and development. “They are in the area’s gravel pathways, and sitting underneath the airport’s solar farm. It didn’t get transported off-site and it didn’t go into the landfill.”

Arcadis developed the engineering plan and final design. “There are five land-based stormwater strategies designed into this project,” says Patty West, a landscape architect with Andropogon Associates Ltd., a landscape architecture and ecological design firm. These strategies included removing impervious surfaces (the buildings and pavement); re-grading the land to mimic natural topography and slowly route water; creating an inter-connected system of bio-retention basins; soil remediation; and changing landscape cover type by adding plantings and native grasses, which help to evapotranspirate stormwater back into the atmosphere.

Once the area was clear, workers began improving the soil. This involved decompacting and treating the soil with a “compost tea” designed to reintroduce microorganisms back into the ground. “Soil is a complex living system,” West explains. “There are bacteria, fungi, nematodes, ciliates and amoebas in there, and they all need to work together with plant roots to start necessary nutrient cycling for a healthy meadow or forest. We needed to add those critters back into the soil, which was essentially dead after years of being under a parking lot.”

Crews then graded the land in a way that mimicked natural flow patterns. Because Tennessee is a mountainous state, this included adding small hills and other terrain variations. They also created bio-retention areas to hold stormwater until it is absorbed into the ground. “This is not just a flat field of green, which would have been very easy to do,” says Yakimowich. “The team designed in contours and created passive walking areas that people could enjoy.”

Green says the project disconnected the city’s stormwater system from the area. Instead, during hard rains, water spilling on the roadway gets diverted into large bio-retention ponds, where the composition of the soil and the vegetation itself acts as a sponge, absorbing and purifying the water before it hits the groundwater table.

The last step recreates a vegetation cover of prairie grasses, trees and other vegetation. “We planted native vegetation that was here before the settlers came. This vegetation is adaptive to the climate here and doesn’t need a lot of water and fertilization. It’s root system is very deep so it really helps water infiltrate the ground,” says Green.

Employees from Arcadis, the CMAA and the City of Chattanooga recently planted more than 600 trees. The trees included Redbuds, Sumac and Dogwoods, with mature heights of less than 4 feet, keeping the airport’s line of sight clear. The trees also do not produce seeds or berries that might attract wildlife. “Meadow grasses were also planted,” says Yakimowich. “We all wanted to create something that was very natural.”

Though it will be months before the vegetation fully takes hold, Yakimowich deems the project a success. “We were recently able to handle a significant rainfall event without flooding,” he says. “We restored the natural balance that existed long before those car dealerships and roads were in place.”

The city added sidewalks along the road and gravel pathways allowing visitors to walk through the improved area. The pathways extend to the creek where visitors can enjoy Chickamauga Creek and its levies.

 

Community

This project has paved the way for future developments and improvements of this kind throughout the entire city, says Green. “We have had a good partner in the airport; they bent over backwards to help us,” says Green. “The P3 has been a great way to get what we needed done.”

Education plays a critical part of P3s for the future, adds Yakimowich. A live camera feed documents the site’s progress at http://earthcam.net/projects/arcadis/. Students from Chattanooga State Technical College also produced a documentary outlining the project. “These measures were important because they allowed the community as a whole to see the progress on the site,” Yakimowich says. “

The videos and the project itself are a positive addition to the airport’s educational tours, which are designed to provide schools and other community groups with information about the airport’s sustainability projects and environmental goals.

These efforts demonstrate the site’s transformation, showing exactly what happens when a community comes together for the greater good. “If you looked at the site before, you would have characterized it as hard, dirty and hostile,” Yakimowich says. “Now it’s clean, green and inviting.”

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