By Chris Landers
ANNAPOLIS – The Maryland Department of the Environment says 19 dams in the state are a potential hazard to the lives and homes of people living nearby.
Where are those dams?
That’s a secret.
The dams, although rated in “poor” or “unsafe” condition and “high” or “significant” hazard, pose no immediate threat to life or property, according to MDE dam safety experts.
Those experts, fearing that the dams would make attractive targets for terrorists, redacted most of the identifying information from a set of dam inspection reports released last week as part of a public information request. Names of the dams were blacked out, as were the owners. The height of the dam was deemed classified. Length was not.
“The reason is security,” according to Cas Taherian, an engineer with the Department’s dam safety program. “We can’t disclose the names and locations. I can’t make any comments on that. If the information is available other places, we have no control over that.”
The information, or most of it, is available in other places.
One of those places is the internet. A comparison with the Army Corps of Engineers’ online inspection database yields the names of 16 of the 19 dams censored from the department’s reports. Another web site, this one from the Maryland Emergency Management Administration, gives details about the people and places that would be affected if the specific dams were to fail.
The Army Corps database is available for download online, and includes latitude and longitude for each dam, names and owners, along with a host of other details. Owners of several of the dams were able to confirm that their dams were the ones reported by MDE.
One of those owners was the Army Corps itself.
Spokeswoman Mary Beth Thompson said the Corps was working on updating its Jennings Randolph Dam in Bloomington. MDE lists it as “unsafe” due to an inadequate spillway, although it says “the dam may otherwise be in good or excellent condition.”
“The Corps of Engineers disagrees with the term unsafe,” Thompson said. “It’s structurally sound and performs as it should.”
Ken Pensyl, manager of Maryland’s dam safety program, said the designation “unsafe” was a technical term – part of a ranking system set up by the Army Corps of Engineers. While high risk dams like Jennings Randolph pose a threat if the dam were to fail catastrophically, the designation is not related to the condition of the dam.
“When you use the word unsafe,” Pensyl said, “that raises a huge [unwarranted] alarm.”
MDE’s criteria for safety, handed down by the federal government, are partly based on a “probable maximum flood” – a storm dropping around 28 inches of rain in six hours. The Jennings Randolph dam, according to the report, would be unable to handle half that amount.
Without disclosing any dam names, Taherian spoke generally about the probable maximum flood.
“It’s not that the dam is going to fail,” he said. “It just can’t handle what we sometimes call the Noah’s Ark storm.” Taherian and Pensyl both said such a storm, while rare, was within the realm of possibility.
“It can and does happen,” Pensyl said. “What we try to do is be prepared ahead of time.”
In cases where the unsafe rating was due to spillway conditions, Taherian said the danger lies in the dam being overtopped by a large storm.
The T. Howard Duckett Dam in Prince George’s County matches all of the available information with a dam rated unsafe in an MDE report. Neither the department nor owners Washington Suburban Sanitary Commission would confirm that they were one and the same, although it is the only dam in the corps database that meets the criteria.
Commission spokeswoman Lydia Wilson said that without the name of the dam, she was unable to confirm that they were the same or comment on the current safety rating, but said the Commission was working on upgrades to the dam.
A 2004 Hazard Mitigation Plan from the Maryland Emergency Management Administration, available on the administration’s web site, cites the Duckett dam, which forms Rocky Gorge Reservoir, as a particular concern. The report lists 48 high hazard dams along with populations and critical facilities within their flood zones.
“Of all Maryland’s high hazard dams,” the report says, “the Rocky Gorge Dam has the largest population within its danger reach.” If the dam failed, the report continues, “an estimated 19,103 persons would be affected.” The flood zone contains three schools, a nursing center and a volunteer rescue company.
Melinda Lee, principal of Laurel Elementary, said she had never been contacted about the danger posed by the dam. Deerfield Run Elementary School principal Thomas Tucker said he heard had of it only because his school is an evacuation center for lower-lying apartment buildings nearby. Tucker said twice in the past five years, his school has prepared to host an evacuation when storm waters approached dangerous levels, but the evacuations were never called for.
Sarah Mayfield, spokeswoman for the Association of State Dam Safety Officials, said that while her organization had no position on releasing information to the general public, those affected should be made aware of the risks.
“There would be some aspects, I suppose, that could pose a security risk,” she said. “People living downstream should be informed. There should be emergency action plans and people should know what they are.”
Pensyl said that plans were in place for owners and state and local government agencies who would be involved in an evacuation.
“All we’re trying to do is protect the dam owners as far as security issues,” he said. “Measures are always taken to make sure the dams are safe.”
Of the 19 dams in MDE’s inspection reports, three are listed as being in “imminent danger of failure.” They were confirmed by the owners to be the Loveton Farms stormwater management facility in Baltimore County; Crabbs Branch stormwater management facility in Montgomery County; and Coulbourn Mill Dam in Wicomico County.
Gene Gopenko, senior engineer of storm water facilities in Montgomery County, said the county was aware of problems at Crabbs Branch and is working to correct them.
“If there’s a significant problem then time is of the essence,” he said. “We have some time, that’s why we’ve decided to do some additional planning.”
Gopenko said the earthen dam runs under a road, and over the years has had problems with sinkholes on the downstream side. The county has filled the holes as they occur, but in the next few weeks they will begin construction on a more permanent solution. Next spring the downstream side of the dam will be extended to deal with the sinkholes.
Al Wirth, of Baltimore County’s Department of Public Works, said the Loveton Farms dam was “definitely a concern,” and that his department had been working for years to have it taken out completely. Wirth said they were working on an environmental study to determine the effect of removing the dam.
When the Loveton Farms facility was constructed, Wirth said, there was a “small country bridge” just downstream of the dam. It has been replaced by a modern bridge. Wirth said the danger comes from the possibility that the spill pipe of the dam could become clogged, allowing water to build up behind the dam, and releasing a torrent if it were to break.
“If it were to fill up with water and break,” Wirth said, “it could be a hazard. It’s better to let the water spread out over the floodplain.”
Without referring to Loveton Farms, Pensyl said it was “highly unlikely that you would have all these events, but that’s what dam safety is all about.”
Wicomico County’s Coulborn Mill dam, which runs under South Division Street between Salisbury and Fruitland, was classified unsafe in 2004, according to the MDE report.
The report, confirmed by Edwin Heatwole, chief civil engineer of Wicomico County’s Department of Public Works, reads “Changed condition to ‘UNSAFE’ due to poor condition and inadequate spillway capacity since dam is now classified as HIGH hazard.”
Heatwole said that reclassification has added to the difficulties of fixing the dam, because it makes it necessary to develop an emergency plan, adding to the cost and paperwork required of the county. Heatwole said he is expecting redesign plans for the dam to be available “any day now” from the engineering firm that will allow construction to begin replacing the overflow pipes for the dam. “The road has never been topped,” he said. “It’s never even come close. Its one of those projects that actually snowballed because of the state reclassification. It’s a tremendous amount of paperwork. We had hoped to get it done two or three years ago.”