Recently a concerned citizen visited the ESI office and provided a preliminary report from McClelland Consulting Engineers titled “Main Street Storm Drainage Tunnel” which concludes that the storm drainage tunnel underneath City Hall, the Carroll County Courthouse, the Auditorium, other buildings and a number of parking lots on North Main “is beginning to fail in such a way that it is no longer able to provide necessary structural support to the buildings and parking areas above it. The City desires to consider alternatives for rectifying this problem and has commissioned this engineering report of study.”
However, the report is about 14 years old, and the current situation is not known. Director of Public Works Simon Wiley said the report is from around 2010. “We do not have a more current engineering report,” Wiley wrote in an email.
Since that report, sinkholes in parking lots near the courthouse and at the intersection of Flint and Main Sts. required extensive and expensive excavation and repair work. Recent repair work done on sinkholes under the parking lot of Eureka Live was suspected by a landowner downstream to be the cause of a fish kill in Leatherwood Creek next to her home where the water emerges from underground.
Mayor Butch Berry said the tunnel is an issue for many property owners who have property built over Leatherwood Creek.
“Several property owners, including John Cross, Lee Pohl and the city, have had to address the issues of the parking lots failing due to the historic tunnels collapsing,” Berry wrote in an email. “In 2016, the City Council and the Planning Commission held several workshops (I think three) to discuss the merits of forming a tax increment financing district.
“Afterwards, I held several town meetings with the North Main Street property owners trying to determine a method of financing repairs of the tunnels under their buildings. At that time, we could not get a consensus of property owners willing to form a tax district and the matter was dropped. This is the only solution that we could find that would finance repairs.”
Berry provided a link to an August 17, 2016, article in the Eureka Springs Independent by Nicky Boyette regarding a group of 13 who gathered in the Auditorium to discuss establishing a Central Business Improvement District as a strategy for funding ongoing repair and maintenance of Eureka Springs’s century-old tunnel underneath downtown buildings. eureka.news/public-not-sold-on-improvement-district/
The article said the tax district was opposed by people who own property along Leatherwood Creek but not in the area where the creek is underground. The article quoted former alderman Dee Purkeypile saying he had fixed the wall along Leatherwood Creek in front of his house, and did not see the improvement district idea as a benefit to him.
“I’m gonna say no to the district. Establishing a taxing authority is not to my benefit,” Purkeypile remarked.
He said as an engineer, he had explored the tunnel and considered the sections below the buildings to be in good condition. It was the sections under the parking lots that have problems.
Alderman Harry Meyer said he agrees that the tunnel is a greater concern under a parking lot than under buildings due to parking lots having the weight concentrated over the tunnel.
“The tunnel just wasn’t designed to have parking over it with cars and heavy buses moving around on it,” Meyer said. “The largest part of the foundations of buildings downtown are not over the tunnel. And where there are buildings above the tunnel, the weight of the building is more distributed.”
Meyer does see problems occurring if one part of the tunnel collapses and water can no longer flow through the rest of the tunnel – imagine Leatherwood Creek after a heavy rainfall running down Main Street. He said he does think foundation repairs of wooden support structures are needed for the Auditorium.
“When I was on the City Advertising and Promotion Committee, we adopted the Aud except for insurance and the light bill,” Meyer said. “But it appears that the CAPC is now waffling about paying for repairs.”
The McClelland report of 14 years ago said doing nothing is not acceptable.
“This structure is located on the east side of Main Street and carries storm water from a point approximately 1,500 linear feet upstream of the intersection of Main Street and Flint Street,” the engineering report states. “This conduit is approximately 100 years old and is comprised of many different cross sections and materials. Some sections are hand-cut native limestone that appears to have been dry-stacked in place while others are made of stone masonry with cement mortar joints and a concrete roof. Some areas have been supported by railroad timbers and/or other timbers.”
Alternatives discussed included doing nothing. “This has a zero initial cost but has a potentially catastrophic cost in the future if the tunnel is allowed to continue to deteriorate, resulting in loss of property and, possibly, life,” the report states.
Option Two is a combination of repair of those parts of the tunnel that lie underneath buildings using a “Gunnite Method,” and replacement of those parts of the tunnel beneath parking lots with pre-cast concrete box culvert. The initial cost of this option was estimated to be $3.75 million in 2011 dollars.
Option Three is the abandonment/filling of the existing tunnel and complete replacement with a pre-cast concrete box culvert that would roughly parallel the route of the existing tunnel. That option would accomplish the objective to prevent a catastrophic structural failure of the tunnel and allow for a new drainage system.
“However, one major problem with this option is that it would require a ‘complete’ solution instead of allowing a staged approach,” the report states. “There would be essentially two linear construction sites parallel with Main Street for a significant period of time creating serious disruptions to downtown merchants, and its total cost is estimated to be $6.1 million. The approach is drastic in nature and the likelihood of unforeseen obstacles is high. It would require all utilities to be relocated. It is likely that street drainage piping would have to run under the street for some distance in order to go around buildings before being routed to the new tunnel. All minor lateral drainage pipes from roofs would have to be identified and routed to the new tunnel.”
The firm recommended option two as less costly than the third option and favorable because it lends itself to staged implementation. The overall project could be divided into several smaller projects allowing the most critical problem areas to be addressed first.
“The cost of each stage can be controlled to match the funding that is available at the time,” the report states. “The construction periods can be shortened to accommodate the City’s various tourism seasons.”