TVA stabilizes dams at coal ash ponds

TVA stabilizes dams at coal ash ponds

October 21st, 2010 in News

A consultant hired by TVA to assess the safety of the utility's coal ash and gypsum ponds said Wednesday that only half of the 24 earthen dams at the TVA ash ponds meet the top safety standard for stability.

But Stantec Consulting Services reported that none of the ash ponds present an immediate danger of failure like the 2008 Kingston ash spill that poured 5.4 million cubic yards of coal ash into the Emory River from a dam breach at the Kingston Fossil Plant.

"We've not seen any conditions in the field that suggest to us that we have any imminent failure in front of us, and we're making improvements," said John Montgomery, Stantec's senior principal engineer. "Every recommendation that we have made to TVA is being picked up and acted upon."

Among the four coal ash ponds initially identified by Stantec as "highly hazardous," only the ash pond at the Cumberland Fossil Plant near Nashville is still rated has a high hazard because of its proximity to a highway bridge.

"TVA is currently working with other agencies to mitigate that risk," Montgomery said.

By lowering the pond levels, buying up adjacent property and improving the drainage and slope of the earthen dams around the ash ponds, TVA has limited the risk of a spill to within federally accepted guidelines at the Widows Creek, Bull Run and Colbert Fossil plants, officials said.

"We never want another Kingston to happen again," TVA Senior Vice President Bob Deacy said.

By the end of 2011, TVA expects to have completed at least 86 ongoing engineering and construction projects to improve the safety of its ash ponds to comply with the highest standards set by federal regulators, Deacy said.

TVA regularly monitors the safety of its river dams, he said, but the utility did not previously rate or inspect its earthen dams around ash ponds in the same way that other such dams are federally inspected.

Since the Kingston spill, however, TVA has spent more than $20 million to assess and upgrade its ash pond impoundments, TVA Vice President John Kammeyer said.

The federal utility plans to spend from $1.5 billion to $2 billion by 2019 to convert its six coal plants that still use wet coal ash disposal to dry ash disposal or recycling, Kammeyer said.

Critics of TVA's ash disposal methods said they were encouraged by the utility's improvements, "but you have to remember that the Kingston ash pond was never identified as hazardous before it collapsed," said Lisa Evans, a staff attorney for Earthjustice, an environmental group based in Washington, D.C.

She noted that TVA made its announcement on its coal ash storage efforts only days before the U.S. Environmental Protection Agency will hold hearings to discuss whether to officially regulate coal ash as a hazardous material.

"The timing of TVA's announcement just a week ahead of EPA's coal ash hearing next week in Knoxville looks like TVA is still trying to put the best spin on this issue," she said.

At the Widows Creek Fossil Plant near Stevenson, Ala., TVA has grouted abandoned spillway pipes, reshaped and strengthened the slope of the earthen dams around the main ash ponds and capped and closed old dredge cells. The dam walls have been inspected and buttressed with rock and sand and the level of the pools has been reduced to avoid a spill like one in early 2009 from one of the Widows Creek gypsum ponds.

TVA is taking a leading role among U.S. utilities in phasing out wet ash storage, Montgomery said. But nearly all utilities with coal plants are studying and upgrading ash disposal methods in the wake of the Kingston ash spill -- one of the worst environmental disasters in decades for a U.S. utility.

The spill occurred when a portion of the Kingston Fossil Plant's ash storage facility collapsed in the early morning hours of Dec. 22, 2008, dumping more than 1 billion gallons of ash sludge over nearly 300 acres of river and land near the plant.

TVA is spending up to $1.2 billion to clean up the Kingston spill.


BY THE NUMBERS

* 24 -- Number of gypsum and coal ash ponds at TVA fossil plants

* 781 -- Number of borings into TVA earthen dams, drilling the equivalent of more than nine miles into the impoundments

* 472,324 -- Number of staff hours spent on upgrading ash pond impoundments.

* 455,305 -- Tons of rock added to the reshaped impoundments to boost the security of the dams

* 86 -- Number of active projects at TVA's 11 coal-fired plants

Sources: Tennessee Valley Authority, Stantec Consulting Services


WHAT'S NEXT

The U.S Environmental Protection Agency will conduct a public hearing on its proposals to regulate coal ash from power plants from 9 a.m. to 9 p.m. Wednesday at the Knoxville Marriott, 500 Hill Ave., in downtown Knoxville.


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