Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, July 4, 1995 TAG: 9507050054
SECTION: VIRGINIA PAGE: C-1 EDITION: HOLIDAY
SOURCE: CATHRYN McCUE AND SHEBA WHEELER STAFF WRITERS
DATELINE: LENGTH: Long
When Timberlake dam near Lynchburg broke two weeks ago during torrential rains, Duncan McGregor went into high gear.
It was the kind of disaster McGregor has spent a lifetime guarding against. As the state's dam safety inspector for Western Virginia, he began calling the owners of the 106 permitted dams in his area to make sure they'd checked for erosion, leaks and other signs of potential problems.
"It's not something we do on a regular basis," he said, but the heavy rains and flash floods were unusual. No problems had been reported as of late last week.
But there are dozens more dams in Western Virginia - and more than 1,000 throughout the state - too small to come under the state's dam safety program.
"No one knows for sure what condition they're in," McGregor said. These dams are usually earthen, built decades ago. And without constant vigilance by the owner or state oversight, they are more likely to give way than the big, tightly regulated concrete dams.
In 1981, shortly after a number of catastrophic dam failures across the country, Virginia passed the Dam Safety Act. It covers dams 25 feet or higher with a reservoir capacity of 50 acre-feet or more. (An acre-foot is the amount of water that would cover an acre of land one foot deep.) Small dams used for farm ponds, as well as those regulated by the federal government - such as the Smith Mountain Lake and Claytor Lake dams - are excluded from the state's program.
Each dam is classified according to potential loss of life and property in case of failure and must be periodically inspected by a professional engineer. The owners also must file emergency action plans with local and state officials. Four regional inspectors oversee the 462 dams covered by the program; a fifth position has remained vacant since May.
The inspectors think about dam safety every day, "not just when one fails and everybody gets excited," McGregor said.
Just two days before the Timberlake dam failed, resulting in two deaths, Joe Haugh, chief of the dam safety program in Richmond, wrote a nine-page memo to his supervisor outlining the state's program and his concerns.
Complacency topped his list. Most people aren't surprised to learn there are 1,500 lakes in Virginia. They don't realize, however, that only two are natural, including Mountain Lake in Giles County.
"The remainder are created by dams - dams that cannot be taken for granted," Haugh wrote.
The dams are getting older, he continued, and "many probably never had any engineered design. They were built out of whatever material happened to be available at the time."
Earthen dams can last a long time if taken care of properly, but many owners simply don't know how to do that, Haugh wrote.
Another concern is urban sprawl. He estimates that 70 percent of the regulated dams could be reclassified to a higher hazard because of development downstream, meaning more people would be in jeopardy in case of a break.
"You build one house or two houses below a dam, and all of a sudden a Class 3 dam turns into a Class 1 dam," he said.
Dam safety is not a glamorous field, Haugh concedes, and it's sometimes a struggle to raise public awareness. In that regard, disasters like the Timberlake dam failure help their cause.
Just last week, the NBC newsmagazine "Dateline" aired a program on dam safety nationwide and led the story with the Timberlake failure. McGregor was interviewed by the "Dateline" researchers months ago.
"I don't have any that I feel like are going to fail on a sunny-day basis," he said, but the constant rains of the last couple weeks prompted him to get on the phone and start making the rounds. "There are some problems out there. They're not all totally up to snuff," he said.
Three of the 26 state-regulated dams in the Roanoke and New River valleys are operating on conditional permits, meaning they're safe but don't meet the state's criteria for spillway capacity, among other possible problems, Haugh said.
They are:
nSpringhill Lake Dam on a tributary of the Big Otter River in Bedford County, owned by the Springhill Lake Association.
nHogan Dam on Hogan Branch in Pulaski County, owned by the town of Pulaski.
nUpper Blackwater River Dam on a tributary of the North Fork of the Blackwater River in Franklin County, owned by the Soil and Water Conservation District.
"We continuously inspect our dams," said Claude Webster, emergency services coordinator for Franklin County, adding that he had just checked the dams last week. "These earthen dams are not like those in Timber Lake. These are very well constructed and intensively inspected."
Keith Boyd with the Soil and Water Conservation District said he went out to look at the agency's two dams on the Upper Blackwater River after the rains on Thursday.
"I was amazed. On one, the water was up two or three feet, and the dam did exactly what it was supposed to do." It held back the extra storm water and released it slowly through a spillway, he said.
If inspectors deem a dam hazardous enough, they have the authority to shut it down, breach it or take other measures and send the owner the bill, Haugh said.
Since 1991, the number of regulated dams not in compliance with the standards has dropped from 47 to four, according to Haugh's memo.
Investigators blame excessive rainfall for the Timberlake failure, not the dam's structural soundness. Still, Haugh and his staff are hoping the disaster will focus attention, from the public and elected officials, on the need for vigilance over the state's dams.
by CNB