Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: WEDNESDAY, June 28, 1995 TAG: 9506290012
SECTION: VIRGINIA PAGE: A-1 EDITION: METRO
SOURCE: RICHARD FOSTER STAFF WRITER
DATELINE: LENGTH: Medium
The now-defunct Peaks View Corp., which once owned the lake and dam and developed much of the land around it, took the Virginia Department of Transportation to court in May 1992 over sediment and water runoff into the lake from construction on the nearby U.S. 460 bypass.
Though the lake owners lost their lawsuit, they learned a few things. Several experts testified that residential and commercial development in Timber Lake's watershed put the lake at great risk of flash flooding that could overwhelm its dam during heavy rains.
"Court papers will show the dam had deficiencies because of changes in the drainage area," said Bernard Proctor, a Lynchburg consulting engineer hired by the lake owners.
"The decision of the jury didn't change my opinion," he said. "There was sedimentation and runoff as a result of construction. The additional runoff would definitely have an impact on the dam."
Courtroom theory became reality Thursday when the dam burst, sending millions of gallons of water into Buffalo Creek, knocking stalled cars from the road and killing two people.
Changing grasslands, forest and farms into pavement, highways and homes means less rain is absorbed by the ground. Rainwater moves faster along pavement and hard surfaces. What isn't absorbed into the ground goes into the lake, Proctor said.
Two Radford University geologists hired by the state Department of Transportation as technical experts for the trial prepared a computer model in 1991 that showed how outside development contributed to runoff.
In 1926, the year the dam was built, only about 22 percent of all rainfall made its way into Timber Lake, according to Chester Watts and Bob Whisonant. By 1990, because of increased development, 40 percent of rainwater was going into the lake.
Most of the construction took place in recent years. From 1972 to 1990, undeveloped land in the lake watershed decreased by 20 percent. As Watts and Whisonant demonstrated with a computer animation model Tuesday at Radford, development ate up the farmland like an invading virus.
The geologists, the Timberlake Homeowners Association, engineers with the state Department of Conservation and Recreation and almost everyone else agree that the dam break was caused by an unusually large amount of rain falling in a very short time - 8.5 to 10 inches in less than 24 hours.
In 1927, a year after the Timberlake dam was built, a similar storm caused the lake to crest one foot below the top of the dam.
This time, however, water poured over the top of the earthen dam, which caused the rapid eroding that tore it apart.
That's the difference of the added runoff from development, Watts and Whisonant said.
The homeowners in Timberlake knew the extra rainwater could tax the dam and its spillways. But, Proctor said, "A private lake like that will find it difficult to come up with the money to upgrade its structure to meet the many changes in its drainage area that it has no control over."
And, Watts said, court records showed state officials overseeing the dam didn't force changes to be made.
In their 1992 lawsuit, Timber Lake's owners hoped to get the state Department of Transportation to pay for extra spillways to compensate for increased water flow from highway construction, according to their attorney, James Sakolosky of Lynchburg.
But, as the Radford geologists testified, the highway construction contributed very little to the runoff. Most of the problem was residential and commercial development north of the lake that had no measures to prevent storm water from flowing into the lake, Watts said.
Because spillways controlled the lake's elevation, sediment in the lake didn't add to the water level. It just made coves shallow and difficult or impossible to navigate by boat.
Sakolosky tried to prove that most of the sediment came from the highway construction.
The jury wasn't convinced and ruled for the state, and the trial was largely forgotten until last week.
by CNB