MILL SPRING – The Polk County Board of Commissioners recently received a report from the N.C. Department of Environmental Quality (DEQ) that revealed maintenance items at Lake Adger’s Turner Shoals Dam that must be monitored and addressed.

Commissioners met on Dec. 4 and heard from county engineer Dave Odom about the DEQ report.

The DEQ inspected the dam on May 16 and sent its report to the county in November.

The issues include deterioration at various locations on the dam, including an area and joints around the intake of the penstocks, joint on the left side of intake structure, right top section of the intake structure, multiple areas on the downstream slope in the arches; seepage through many of these areas of deterioration and along the toe of the bulkhead area, and seepage in several of the arches.

The DEQ also recommends the county provide numbering on the face of each of the bays to aid in any emergency response situation.

“Continued deterioration of the concrete undermines the structural integrity of the dam,” states the report. “Seepage contributes to the deterioration by leaching constituents of the concrete and promoting freeze/thaw damage.”

Odom said each of the items noted, with the exception of the numbering of the bays, was addressed in the stability and analysis report that was submitted to the DEQ a couple of months ago. Odom said that report is in review by the state and it is not known how long it will take to be completed, but once it is complete, the county can begin the design process to make the repairs.

“But we can’t begin the design until we get that process completed by DEQ,” Odom told commissioners. “It’s an absolute necessity to have that completed and approved first.”

Commissioner Tommy Melton asked Odom to explain the needed repairs in layman’s terms where he can understand what is wrong with the dam.

Odom said it’s just 100-year-old concrete that has surface deterioration at various locations and it’s worse in some places than others.

Odom said the recommended repairs will do a couple of things, including taking care of the surface deterioration as well as bulking up the bays themselves, by adding additional concrete mass, which will provide better stability for events like earthquakes.

Odom continued by saying there are two types of concrete: concrete that has cracks and concrete that will crack.

“All concrete has minor cracks in it,” Odom said. “And there’s several places throughout the dam that have just very, very minor cracks and a little bit of water seepage through them. It’s been that way for decades. We inspected it several years ago, probably five years ago when we got the very first inspection report.”

Odom said engineers have been out to the dam several times since then and haven’t noticed any increase in the seepage rate. He doesn’t think it’s going to increase and the repairs recommended will correct that.

The DEQ also investigated the potential for property damage and loss of life in the event the dam fails.

“This investigation determined that failure of your dam could result in serious property damage and possible loss of life,” states the DEQ report. “Therefore, we are listing your dam in the ‘High Hazard’ category.”

The county has known for years the Turner Shoals Dam is categorized by the state as a high hazard dam. Odom explained that there are three classifications of dams the state recognizes: low, medium and high.

“It’s not a function of the condition of the dam,” Odom said, “it’s a function of what would happen if the dam were to fail. We’ve got a road directly down stream from the dam, so if we had a breach, then there’s a high potential for a loss of life if a car were on that bridge. That’s what’s that’s referring to. We’ve had that classification for a long time.”

Commissioner Ray Gasperson asked Odom if the dam were brand new in that same location would it have the same classification. Odom said it would still be classified as high hazard because of its location.

 

The DEQ report also mentioned that the county is required to submit an emergency action plan (EAP) to the state. The report said the latest EAP report for the Turner Shoals Dam is from Oct. 19, 2010. The report said dam owners are required to submit their EAP by Dec. 31, 2015 and since that date has passed, the EAP must be submitted by Jan. 1, 2018.

 

Odom said the EAP was updated in 2013 and he’s working to get it uploaded to the state’s new portal system now.

Odom also said this week the design for the repairs will begin once the state accepts the stability analysis report. He said the time frame on the repairs will be roughly one year and the last estimate on the repairs was approximately $3 million.

Polk County purchased Lake Adger almost a decade ago, which included the Turner Shoals Dam.

Commissioners also heard from Lake Adger resident Sky Conard during citizen comments on Dec. 4. Following is her statement to commissioners regarding the DEQ report.

 Sky Conard:

As you are about to hear, the Dam Safety Inspection with Monitoring report for 2017 will be completely identical to the one issued 5 years ago, with the addition that now the county has failed to update its Emergency Action Plan(EAP) from 2010.

The reason that the reports don’t differ, is because nothing has been done to ‘Address’ (repair) or ‘Monitor’ (re-evaluate) the deteriorating concrete and seepage maintenance items found back in 2013. And Polk still has not numbered the (arched) bays, which would aid in any emergency response- as recommended x 2.

I don’t understand why Polk doesn’t get a “Notice of Deficiencies” from NCDEQ with the AECOM Dam Comprehensive Stability Evaluation being a year late (2016) and the next phase of Design & Permitting undone (due 2017). This is what ‘to monitor’ and ‘to address’ means in DEQ language and what they said ‘must’ be done in their inspection reports – and it’s not!

As DEQ/dam safety engineer William H. Denton IV stated in an official letter to Polk County back in Oct 12, 2015… (The one where county engineer/David Odom urged DEQ to write and what to say, extoling Polk’s diligent work efforts to date):

…..”As always, it remains the dam owner’s responsibility, in this case, Polk County’s responsibility, to maintain and operate its dam in a manner that protects that downstream public. As it states in NCGS article 143-215.35, nothing in the Dam Safety Law “shall relieve an owner or operator of a dam from the legal duties, obligations and liabilities arising from such ownership or operation.” As such, we encourage the County to follow through on actions recommended in the report by AECOM in a timely fashion and to take all other steps necessary to protect the downstream public.”

That ‘public downstream’ of Polk County’s 93yr old High Hazard Turner Shoals Dam, to be protected, would include the Tryon International Equestrian Center where all the world will be watching Sept. 2018 @ World Equestrian Games……they need to be an updated contact in Polk’s revised Emergency Action Plan as well.