The Tennessee Valley Authority has had a second leak at an impoundment at a coal-fired powerplant, this time from a gypsum pond at its Widows Creek Fossil Plant in northeast Alabama. The incident prompted Sen. Barbara Boxer (D-Calif.) to announce on Jan. 13 that she plans to seek federal regulation of coal-ash ponds across the U.S.

Shifting gypsum dislodged the cap covering a 30-in. pipe once used to drain water from the gypsum pond into an adjacent settling pond, says John Moulton, a TVA spokesman. Once the cap came off, water in the gypsum pond flowed into the settling pond, which then overflowed into Widows Creek that flows through the site, Moulton says. Gypsum ponds hold limestone spray from scrubbers that clean sulfur dioxide from coal-fired plant emissions. The 1,456-MW Widows Creek plant has wet-limestone scrubbers on two units. TVA reported to the Alabama Dept. of Environmental Management that the spill was about 10,000 gallons. It has placed booms in the creek to prevent material migration, and state officials are on-site to monitor spill effects. TVA will be required to remediate the area, and it is bolstering gypsum pond internal walls.

TVA says results of tests on water and soil samples show that the solid material released was well below what is considered hazardous and that the material contained coal ash, Moulton says. Electrostatic precipitators at one of Widows Creek plant units have not been working for some time, he says. The devices removes fly ash from the coal plant’s air emission stream.

But TVA has still come under fire from the Tennessee Dept. of Environment and Conservation after it discharged sediments behind a dam into the Ocoee River. The department on Jan. 9 issued it a notice of violation for discharging the mixture without a permit. TVA was told to stop the release immediately and submit by Jan. 22 a plan to restore affected portions of the river.

TVA says it released the sediment to reduce the level of the reservoir so it could make repairs to the dam. It completed an environmental assessment before releasing the sludge and did not need a permit, says Jim Allen, a TVA spokesman. But a spokeswoman for the state environmental agency disagrees, noting that TVA “has a clear understanding of the nature of the sediment built up behind the Ocoee 3 dam as a result of site remediation.”

TVA has come under fire since 5.4 million cu yd of wet ash flowed over 300 acres and into the Emory River when a retaining wall fell on Dec. 22 at its Kingston coal-fired plant near Knoxville, Tenn. Boxer said she will ask the U.S. Environmental Protection Agency to regulate coal-ash ponds at the confirmation hearing of Lisa Jackson, President-elect Barack Obama’s nominee to head the agency. Tom Kilgore, TVA’s CEO, said at a U.S. Senate hearing on Jan. 8 he expected more federal oversight. EPA has not set federal waste standards for coal-ash storage or disposal beyond a required wastewater discharge permit.

On Jan. 13, Tennessee issued an order against TVA, requiring it to submit a cleanup plan for the Kingston spill and to obtain an independent assessment of the structural integrity of all its coal-ash impoundments in the state.