Jan 1 - McClatchy-Tribune Regional News - The Knoxville News Sentinel, Tenn.

Leaks, seepage and water-logged walls plagued the fly ash retention pond at the Tennessee Valley Authority's Kingston Fossil Plant for years before the structure's Dec. 22 catastrophic failure, according to the agency's February 2008 inspection report.

While TVA hasn't ended its official probe into the cause of the failure, the report indicates the agency knew about leaks at the site for more than two decades and opted not to pay for long-term solutions to the problem.

TVA spokesman Jim Allen said Wednesday that TVA hasn't determined the cause of the spill and for now was focusing on the cleanup.

"We're in recovery mode," Allen said.

According to Allen, the agency could not immediately respond to questions about the inspection report.

The report details a Dec. 4, 2007, site inspection of the structural stability of the pond that crumbled last week, dumping 1.1 billion gallons of fly ash sludge into the surrounding neighborhood and the Emory River. Fly ash is one of the waste products from coal combustion and contains arsenic, lead, barium, thallium and other substances that can cause health problems, including cancer, liver damage and neurological disorders.

The U.S. Environmental Protection Agency does not consider fly ash to be hazardous waste. The pond is regulated as a Class II landfill by the Tennessee Department of Environment and Conservation's Division of Solid Waste Management. TDEC inspection records going back to 2002 show the pond routinely passed muster, though inspectors occasionally found signs of erosion and seepage.

The pond is a multicell, above-ground pool where TVA placed a mixture of fly ash and water. The fly ash settles to the bottom of a cell, then is placed into dredge cells. The water drains off into the steam plant's water intake.

The pool's walls, called dikes by the agency, are made of bottom ash that is sculpted and landscaped to prevent erosion.

According to the report, seeps along the bottom of the dike where it blew open have been known for perhaps as long as a quarter-century, though inspectors in 2007 didn't find any wet spots.

"The seeps along the toe of Dike C and below the toe of the dike along the intake channel, known since the early 1980s were not visible during this inspection," the report states.

Over the past five years, the dikes have been prone to leaking except when repairs were being made, according to the report.

In November 2003, a leak along the bottom of the dike forced TVA to cease depositing fly ash into the pond's dredge cells.

TVA considered at least eight options to address the leak, according to a Dec. 22, 2003, agency update. Three of the options would have provided a "global fix" to the problem, but high costs were cited as liabilities to pursuing them.

The most expensive option -- converting to a dry fly ash collection system -- would have cost an estimated $25 million. That's far less than the $37 million spent to clean up a 2005 Pennsylvania fly ash spill one-tenth the size of the Kingston spill.

Two other proposed global fixes were to construct a synthetic liner for the pond for $5 million and building a cutoff wall around the perimeter of the dredge pond for $2.6 million. In addition to high cost, TVA noted that using a synthetic liner would set a precedent for all other dredge cells.

TVA opted to repair the dike and install "underdrains," which in a summary of the inspection report the agency likens to residential french drains, "to relieve water pressure."

Repairs were completed in 2005, but the dike sprang another leak the next year.

The report blames both the 2003 and 2006 leaks on inadequate internal drainage, which supposedly was addressed by the underdrains, and water getting into the dikes themselves.

TVA installed "dewatering wells" in 2006, along with 30 piezometers, which are devices to monitor water levels inside the walls.

The report also noted that in November 2007 the agency stopped placing fly ash in the dredge cells, based on recommendations from consultants.

"This preventive measure was taken (in November 2007) to reduce water levels in the dredge cell through the winter months in an attempt to avoid another blowout," the report states.

TVA has not said whether the agency considered calling a halt to dredging this winter.

Another leak was discovered in January 2008, shortly after the site inspection but before the report was finalized. An inspection determined that the water came from an "old underdrain system" and that evidence of iron-laden water proved the water leached out of the ash.

The most recent inspection was conducted in October. TVA has said a preliminary report shows inspectors found a wet spot indicating "a minor leaking issue."

Three days before Christmas, the dike burst.