These are the facts. Seven Lakes West's dam engineer not only recommended that the road over Lake Auman Dam be closed permanently, he took the unusual step of asking the state Dam Safety Engineer to order it closed. The state declined to do so, though it has jurisdiction and authority to order road closure, instead leaving any decision about reopening the road to the community.
If the community chooses to rebuild the roadway across the top of Lake Auman Dam, the level of interest the state takes in that project will depend on how deeply the roadbed and associated drainage structures intrude into the embankment. If the road is reopened to vehicular traffic, and the state, on inspection, finds significant signs of traffic-related stress in the embankment, the state's Dam Safety engineer would likely order the road closed.
Where those facts came from
The West Side's ongoing discussion about whether the portion of Longleaf Drive that crosses Lake Auman Dam should be reopened or permanently closed has generated substantial debate about exactly what Dam Engineer Dr. Dan Marks recommended, as well as whether the State of North Carolina's Dam Safety Engineer has taken a position on the reopening of the roadway.
The Times interviewed the state's Dam Safety Engineer, Steven McEvoy, by telephone on Tuesday, October 5 and Monday, October 11 to try to clarify those issues. We also reviewed copies of the official communications from Marks to the state and the Seven Lakes West Landowners Association [SLWLA] that touch on this aspect of the debate.
What Dr. Marks said
Marks went well beyond recommending the permanent closure of the road over Lake Auman Dam, actually asking McEvoy's office to make permanent closure a condition of the state's final approval of the 2009 repair work done on the dam. Marks' request is contained in the final paragraph of his December 1, 2009 Construction Certification Report, an official document aimed at obtaining a Certification for Approval to Impound from the North Carolina Department of Environment and Natural Resources [NCDENR], the agency responsible for dam safety.
That paragraph reads as follows:
Marks Enterprises recommends that the Certification of Approval to Impound for Lake Auman Dam to be issued by the North Carolina Dam Safety Engineer in the Department of Environment and Natural Resources following review of this Construction Certification Report for the recently completed dam remediation construction be granted only with the following stipulation:
• That section of Longleaf Drive in the Community of Seven Lakes West that transverses the crest of Lake Auman dam shall remain closed to vehicular traffic of all kinds, except for un-licensed vehicles capable of transporting a maximum of two people. Furthermore, no future consideration shall be given to the opening of this section of roadway (resuming the use of this section of roadway for vehicular traffic) regardless of any plans to design and/or construct any type of high-strength roadway pavement design section. [Emphases in original.]
For an engineer to ask for such a restriction is unusual and speaks to the depth of Marks' concern about the impact of traffic rolling over the dam.
SLWLA Director Mick Herdrich, who chairs the Association's dam committee, told The Times that neither he, the Board, nor the Dam Committee knew in advance that Marks planned to ask for this restriction on the state's approval of the repairs. State Dam Engineer McEvoy confirmed that it was out of the ordinary.
"We don't see that a lot," State Dam Engineer McEvoy said of Marks' recommendation. "That's an unusual request."
"We responded to that request in the final approval," he added.
What the state said
"I don't recall that [i.e., permanent closure of the road] being a condition of approval," McEvoy told The Times. McEvoy's office oversees 4,500 dams in the state; 1,100 of those are designated as high hazard dams.
In fact, the state's Final Approval to Impound, signed by McEvoy, did not include the condition that Marks had requested. The relevant paragraph reads as follows:
"In addition it is noted that the design engineer has recommended to portion of Longleaf Drive that traverses the crest of the dam embankment remain closed to vehicular traffic in order to insure the integrity of repairs to the dam. Though we do not consider road closure a requirement for continued operation of this dam, you as the dam owner may wish to consider the design engineers' recommendation in this matter."
Much has been made in the ongoing Westside debate of the meaning of the word "may" in the state engineer's letter. Some have suggested that McEvoy's "may" is really a "should," softened because McEvoy lacks the jurisdiction to say anything stronger.
The Times questioned McEvoy closely on this point, asking him directly whether he meant "should" or "shall" and whether he was constrained by his jurisdictional authority in the wording he chose.
"This is a 'may'," McEvoy replied. "It's going to be left up to the dam owner. It's left up to the community. I don't know how we can make that more clear."
The state can close a dam roadway
Part of the confusion may in fact stem from a "Letter of Clarification" authored by Marks and addressed to Herdrich as Chairman of the Association's Dam Committee, in which Marks attempts to explain both the state's failure to impose the restriction he requested and McEvoy's use of the word "may." Marks writes:
Mr. McEvoy, P.E., as the State Dam Safety Engineer has no authority and/or jurisdiction to serve as the private dam engineer for the Seven Lakes West Landowners Association . . . .In his statement 'You as the dam owner may wish to consider the design engineer's recommendation in the matter.' Mr. McEvoy, P.E., has come as close as possible to stating an agreement with the recommendation while not acting outside of his authority and jurisdiction.
Marks' is undoubtedly correct that McEvoy cannot, as State Dam Safety Engineer, serve as SLWLA's dam engineer. However, his statement has been interpreted by some as suggesting that McEvoy has no authority to close Longleaf Drive over Lake Auman dam, and that is clearly not the case.
McEvoy explicitly stated in an interview with The Times that his office could and would close the dam road to vehicular traffic if they found clear signs of stress to the dam's structure linked to travel over the dam.
"We would not order the road closed unless we see signs of changing stress on the dam," McEvoy told The Times. "If we came out one day, and there were signs of stress on the embankment, we might require closure of the road."
Among the problems McEvoy mentioned that might result in an order to close Longleaf Drive across Lake Auman dam were "sloughing on the downstream slope, significant seepage, rutting in the roadway, and apparent distress in the roadbed."
"Any dam that is repaired is subject to re-inspection," McEvoy told The Times. "It's just like a used a car; you might fix it one day, and then the next day it needs something else."
"Sometimes we will close a road across a dam if the dam is in the act of failure," McEvoy said. By way of example, McEvoy told The Times that his office had ordered Camp Easter Road closed over the dam at Crystal Lake in Vass when it developed a sinkhole, which he called "a clear sign of current distress."
As for Lake Auman Dam, "we don't have any clear signs of current failure," the state engineer added.
"We can require a dam owner to close a road," McEvoy said, though he noted that his office typically does not have to take that step, because either the NC Department of Transportation or a local government that has jurisdiction over the dam will step in to close the roadway because of safety concerns.
Would the state have to approve a new roadway?
McEvoy confirmed that his office would need to review plans for any reconstruction of the roadway atop Lake Auman dam. The extent of the review required, he said, would depend on the degree of excavation required. If rebuilding the road requires excavations shallower than twelve inches, the Dam Safety Engineer could declare the repairs "non-jurisdictional," in effect, taking a hands off approach. More extensive excavation would likely result in more extensive review by McEvoy's office.
"Many times we will allow paving across a dam without approval, if it just involves pavement and and no excavation into the embankment for drainage structures and piping," McEvoy told The Times. "When you excavate into a dam, that's when we get involved. Many times road repairs involve just eight to twelve inches. As long as you're not excavating into embankment, we're not going to be heavily involved."
Would the state approve Lake Auman Dam today?
The claim that Lake Auman Dam could not be built in today's regulatory environment is one that surfaces from time to time in the debate about the dam and dam roadway.
The Times asked McEvoy to comment on that notion: "It's been said that, should the dam fail, the state would never allow it to be rebuilt. Is that accurate?"
"I'm not sure I could say that," the state's Dam Safety Engineer responded. "With the right funding and right engineering effort, you could design a dam there."
The Times asked whether such a project would necessarily involve a concrete core, as opposed to the current earthen structure.
"That's a possibility," McEvoy said, "but earthen dams can be engineered that have internal zones. They can be designed by using different types of soil to create zones in the structure." The current Lake Auman Dam is in fact such a "zoned" structure, with a less porous clay core, which Dam Engineer Marks has suggested appears to have been imperfectly constructed.
"So the state hasn't given up on earthen dams?" The Times asked McEvoy. "No," he replied. "The vast majority of dams in the state are earthen."
The Times noted that the earthen dam at Hope Mills Lake in Cumberland County, after failing, was replaced by a concrete structure. McEvoy replied that the use of concrete in the replacement dam was not something the state had mandated.
The Times asked whether, if Lake Auman Dam were being built today, stricter standards would prevent a roadway being placed atop the embankment.
"I do not think that would be the case," McEvoy replied.
The Times asked whether it was unusual, in today's regulatory environment, for a road to be placed upon the embankment of an earthen dam.
"No, that is commonly done," McEvoy replied. "That's not at all unusual."
