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Stormwater Engineers 'Turned a Parking Lot into a Creek' 
Chris Howley, the City's Stormwater Chief, describes it simply: "We turned a parking lot into a creek."

But there was a lot more involved with a $800,000-plus private-public collaboration that has daylighted a tributary of Fourth Creek at Papermill Drive and Kingston Pike. 

A Fourth Creek tributary at Kingston Pike and Papermill Road has been daylighted.

The creek restoration project is important, for a couple of reasons: 

The new stream channel and green buffer will help control flooding downstream.

The project also restores a section of a stream that had, like much of Fourth Creek, been forced into underground culverts over generations of intense development. That alone is ecologically beneficial. The daylighting marks progress toward better water quality and building habitat.

A Fourth Creek tributary at Kingston Pike and Papermill Road has been daylighted.

“For decades, the sole focus of re-channelization was to deal with flooding - containing runoff in culverts. or in some cases concrete-lined ditches," Engineering Director Harold Cannon said. 

"But we lost sight of the ecological impacts that these 'improvements' were having. The engineering community is now realizing that, when opportunities allow these streams to be returned back to stable open channels, there is - without question - an environmental benefit well beyond the channel itself. 

"This approach is also proving to ironically reduce downstream flooding, which was the intent of these culverts in the first place.”

The property at Papermill Drive and Kingston Pike used to be a lower parking lot for restaurants and retailers. But it was prone to flooding.

Decades-old stormwater devices were showing their age: Old metal pipes had begun to fail, the catch basins would fill, and water would rise. Occasionally, commercial property would be damaged by the water. Other times, vehicles would be swept away and need to be fished out using cranes.

But there were also long-standing water-quality problems, Howley said.

"This area has been highly developed - lots of asphalt, and a lot of Fourth Creek has been run underground through pipes," he said. "Dark space limits having a healthy creek. Plants don't grow there, so critters don't go there.

"In this particular area, the Fourth Creek watershed had taken a major hit over the years."

The restoration work at Papermill Drive and Kingston Pike is an environmental stewardship step forward.

Besides daylighting a 238-foot-long section of the stream, red maples, sweetbay magnolias, pond cypress and leatherleaf viburnum have been planted. Larger swaths are being planted with riparian grasses.

“The opportunity to restore a section of any channel is rare," Cannon said. "But stream restoration for sites such as the one near PF Chang is gradually becoming an option that developments are willing to consider. That results in a ‘win-win-win’ for the development, the City and the Knoxville community.”

The City's portion of the work was about $300,000. Regas Quality Developments funded almost twice that amount.

Balancing competing needs

Making stormwater improvements in any heavily-developed commercial corridor is challenging. How can the City possibly make environmental improvements while controlling flooding, accommodating increasing numbers of through-traveling motorists and bicyclists, and providing safe vehicle, bike and pedestrian access to businesses? 

"It's difficult to balance the sometimes competing needs," Cannon concedes.

Papermill Drive is a case study in complexity and the delicate balance that's required.

Remember the June 29, 2020 gully washer that dumped 5 inches of rain in parts of West Knoxville? Bearden and West Hills were hit hard, and this Fourth Creek tributary (officially named Tributary 2) quickly rose out of its creek bed. Water was standing several feet deep across the entirety of a section of Papermill Road between the Interstate 40 right-of-way and the entrances to businesses on the south side of the road. 

At one point, only a fire engine could be seen making it through the 100-foot-wide expanse of water the night of that summer storm.

So controlling where water goes is crucial - and so is cutting down on erosion. During a violent storm, sediment used to wash from the "Grand Canyon of West Knoxville" - click HERE - along the same Fourth Creek tributary through Bearden and all the way to Fourth Creek and on to Tennessee River. 

That separate Grand Canyon restoration project alone stopped an estimated 20 dump truck loads of sediment each year from washing downstream, and water quality measurements are immediately showing notable improvements.

But traffic safety is also important. The City is studying ways to add a turning lane on Papermill to eliminate traffic bottlenecks and reduce the number of rear-end accidents. There's not much room between I-40 and the Tributary 2 creek bed. Can the road be widened without covering up some of the creek? The City hopes so, but it's not a given. 

Taking advantage of opportunities

The dilemma can be confounding. Safety is always the top priority. But the situation with the Fourth Creek tributary illustrates the need, whenever possible, to restore a creek to a more natural state. Because sometimes in a highly developed area, it's just not always possible.

"I'm glad the City and Regas were able to collaborate on rejuvenating the steam at Papermill and Kingston Pike," Cannon said. "The opportunities to do this can be far and few between, and when an opportunity presents itself, when a property owner is willing to share the costs, we want to be able to take advantage of those opportunities."

Below are some additional photos of the Bearden-West Hills project.

A Fourth Creek tributary at Kingston Pike and Papermill Road has been daylighted.

A Fourth Creek tributary at Kingston Pike and Papermill Road has been daylighted.

A Fourth Creek tributary at Kingston Pike and Papermill Road has been daylighted.

A Fourth Creek tributary at Kingston Pike and Papermill Road has been daylighted.
Posted by evreeland On 05 August, 2020 at 11:04 AM