No quick fix
Damaged Suck Creek Road being studied, but no timeline slated for repairs
Rains in recent months have damaged mountain roads all across the Chattanooga region, and one bending around the base of Signal Mountain to Suck Creek Mountain is backing up commuter traffic between Hamilton and Marion counties.
Suck Creek Mountain Road, also known as Tennessee State Route 27, is closed down to one lane near the Hamilton-Marion county line, where the roadway has buckled and cracked from heavy rains and erosion, according to the Tennessee Department of Transportation.
Eastbound and westbound traffic alternate on the one through-lane, controlled by traffic signals on either end of the mile-long stretch of damaged road.
Longtime Whitwell, Tennessee, residents Ed and Linda Hooper said the road is a lifeline for people who live in communities on the north end of Marion County and work in Chattanooga.
Ed Hooper said he took the route from Whitwell to Chattanooga to doctor appointments twice in a week recently and saw no repair work happening. He’s worried that if repairs are delayed until there’s a complete closure, it could send him and other Marion County-Chattanooga commuters
more than 30 miles out of the way to get to their destination.
TDOT said the problem is at two sites where the slope of the mountain failed under the road.
“This area is very challenging for several reasons,” TDOT Region 2 Director Joe Deering said Friday. “We have right-of-way constraints as well as being adjacent to Suck Creek, which is classified as an exceptional Tennessee waterway. There are both environmental concerns coupled with the geotechnical and geographical ones. Also, there is no feasible detour, so developing a solution that can be implemented while keeping the roadway open is important.”
The frustrated Hoopers also want to know why the $19.2 million project on the other side of the river on U.S. Highway 41 seems to get all TDOT’s attention.
TDOT spokeswoman Jennifer Flynn said the best answer was that it failed first, and when it did it was more severe.
“It is still actively moving as we are trying to repair it,” she said Friday, also noting that U.S. 41 is a federal route that serves as a detour when something happens to interrupt traffic flow on Interstate 24. The section of U.S. 41 has a long history of slides and repairs.
The Hoopers contend the state highway gets more traffic than the federal one, and Flynn said the Hoopers are correct.
The average daily traffic count is slightly higher on Suck Creek Road over the mountain from the Hamilton County line to Powells Crossroads in Marion County compared to the segment of U.S. 41 under repair between Tiftonia in Hamilton and Guild in Marion, she said.
Flynn said damage on Suck Creek Road started showing up in small slope failures in May 2019 at the county line near the bridge over Suck Creek as it heads to the Tennessee River. TDOT crews milled sharp edges of the cracks in the pavement, started monitoring the road for more movement and in July 2019 began working on an engineering solution while performing some repairs on the damaged box culvert.
But it was the deadly nighttime storms on Easter Sunday this year that dealt out the most damage, dropping more than five inches of rain on the Suck Creek watershed, doing more severe damage and causing another slope failure a mile up the mountain road, Flynn said.
That night an 8-by-8-foot concrete box culvert under the road started separating along with more slope failures at the lower site, while on the same night the heavy runoff eroded material on the edge of the road under the concrete barriers and tumbled huge foundation rocks that supported the road down the slope toward Suck Creek.
Officials suspect ongoing erosion under the barriers had been hidden from view for some time.
“Within a week of that rain event, the pavement that had only small cracks in July 2019 began subsiding, with larger cracks opening up not just in one lane but both lanes of the road, and also cracks began appearing right where the concrete box culvert lies under the pavement,” Flynn said.
During the next week, TDOT closed the road to one lane by putting up traffic signals, analyzed the box culvert issue and the agency’s geotechnical engineering team studied the problem.
“TDOT then began to work on environmental boundaries and investigated what options would be available for a fix without having to purchase additional right-of-way, and other options that would include additional right-of-way,” Flynn said.
Over the next three days, officials monitored the site every 12 hours and found crumbling material and movement of the slope had almost stopped. The damage left behind, however, had to be fixed.
That site underwent the same environmental and repair study the first one did, she said.
“It was quickly determined that any work that would impact the embankment of Suck Creek would require a long lead time to acquire all the proper permitting, but that the application process for the proper permits could not be fully started until the final repair plan was determined,” Flynn said.
That means there’s no timeline yet on repairs.
“We are beginning the process to request funding to design and let both sections to contract for repair,” Flynn said.
Meanwhile, TDOT has “reached out to its soil stabilization statewide contractor and other vendors to see if temporary measures can be put in place to reopen the road to two lanes during design,” she said.
TDOT has proposals for both sites that are being reviewed by the agency’s Geotechnical Engineering Section and Region 2 Operations, according to Flynn. She also said crews would try to limit the impact on access points used by kayakers, hikers and others who visit the area.