Coal ash ponds of Alabama

The Tennessee Valley Authority's Colbert Fossil Plant in Tuscumbia, Ala. (Dennis Pillion | dpillion@al.com)

((Dennis Pillion | dpillion@al.com))

The Tennessee Valley Authority's Colbert and Widows Creek power plants have already burned their last piece of coal to generate electricity, but some environmentalists are worried that the tons of coal ash left behind in watery ponds could cause environmental problems long after the burners were turned off.

TVA announced plans last month to cover and leave in place retired coal ash impoundments at those and other non-active ash sites throughout Alabama, Tennessee and Kentucky, including the retired plants at Colbert and Widows Creek.

This map, compiled by the Southern Environmental Law Center, shows the locations of TVA coal ash disposal sites and drinking water supplies in Tennessee and Alabama. (Southern Environmental Law Center)

TVA spokesman Scott Brooks said the utility determined that draining and covering the ash ponds was the "preferred alternative" to removing the coal ash, both from a financial and an environmental standpoint.

"EPA's general guidance is that either option could be just as environmentally safe if done properly," Brooks said. "We looked at the potential environmental impact including the potential for groundwater and surface water runoff, and that led us to our preferred option which is closure in place, in most instances."

Several environmental groups -- including the Southern Environmental Law Center, Tennessee Riverkeeper and the Alabama Rivers Alliance -- believe the material should be removed instead.

Coal ash contains potentially hazardous substances like mercury, cadmium and arsenic, and the groups are concerned that coal ash left in place could continue leaching into the groundwater, or into the Tennessee River in north Alabama, which provides drinking water for 700,000 people in north Alabama, according to SELC.

They also worry that a dam breach -- like the one in 2008 at the Kingston, Tenn. plant, which spilled 5.4 million cubic yards of coal ash into the Emory and Clinch Rivers -- could happen again if the ash is left in the current impoundments along the river.

Amanda Garcia, staff attorney at the Southern Environmental Law Center's Nashville office, said other utilities have opted to remove their ash to landfills after new EPA regulations for coal combustion residuals were finalized last year.

"While utilities around the country are recognizing coal ash as one of the biggest environmental and public health challenges today, TVA has blindly rushed forward a plan that would burden Tennesseans and Alabamians with this pollution for decades to come," Garcia said in a news release.

"TVA promised to be a leader in coal ash safety following the Kingston disaster, yet walking away from these sites--as other utilities do the right thing and commit to clean up--breaks that promise."

The facilities in question are mostly wet storage facilities separated from rivers or streams by dams, sometimes made of dirt. Under the cover-and-close procedure, the ash would be dried, removing the water weight and decreasing pressure on the dams and the material underneath would be covered with a liner, clay or topsoil to prevent rain water from penetrating the ash pile. In that scenario, there would not be a lining under the ash.

"Dried ash doesn't go anywhere without a force to move it," Brooks said. "Without water, it's a lot less likely for the ash to move."

The TVA's Environmental Impact Statement (EIS) makes the case that removing the ash could have more negative environmental consequences than leaving it in place, citing among other things, the emissions from trucks or trains used to haul material to an off-site landfill, the potential for accidents or spills in transit.

"Number one, you have to consider the environmental impacts of in some cases dozens of trucks, truck traffic coming in hauling dried ash," Brooks said. "You would also have to consider the environmental impacts of where that ash was moved to.

"You don't consider costs as part of the environmental impact, but you do consider them as a part of reality, and in every case the cost of removal would certainly be exponentially more than closure in place."

Environmental group Tennessee Riverkeeper says discolored soil like this on the banks of Cane Creek, a tributary of the Tennessee River, could indicate possible seepage from a coal ash impoundment. (Dennis Pillion | dpillion@al.com)

Keith Johnston, managing partner of the SELC's Birmingham office, said the ponds at the plants TVA is planning to cover in Alabama have a troubling history.

Johnston cited a 2009 ash spill at the Widows Creek plant, just weeks after Kingston incident, and a consent decree agreement reached between TVA and the Alabama Department of Environmental Management in 2013 to resolve allegations that discharges from the ash ponds violated the Clean Water Act.

"TVA's proposed plan to cover up its ash is not an acceptable solution for any of its sites, let alone for sites that have a history of violations such as Widows Creek and Colbert," Johnston said. "Families and communities in north Alabama deserve clean water and shouldn't have to bear the burden of TVA's continued pollution that threatens their drinking water."

Brooks said TVA was operating within the requirements of its permits for groundwater and surface water discharge and would continue to monitor groundwater even at its retired impoundments.

"After decades of monitoring the rivers, we haven't seen any evidence of harm or risk to drinking water or any human contact," Brooks said. "I'm very comfortable in saying that because we do monitor since those permits have been in place, and we will continue to do so as long as we have those permits."

Brooks also said the development of the old Widows Creek site into a Google data center did not affect this decision, and that the areas where the ash is stored there would not be part of the Google campus.