Updated on Wed., May 28.
Critics of Ameren's proposed coal ash landfill in Franklin County argued Tuesday that it would sometimes be sitting in groundwater.
That's a problem, because most Franklin County residents get their drinking water from groundwater wells ― and coal ash contains toxic substances like arsenic and lead.
In an appendix to its landfill construction permit application (see this document, starting on p.25), Ameren acknowledged that in high water years, the base of the clay liner of the proposed landfill would be in "intermittent contact" with groundwater.
But the report, commissioned by Ameren, said the liner is designed to withstand fluctuations in groundwater and that it would keep the coal ash contained.
Tuesday night's debate between the power company and area residents took place before the Franklin County Board of Zoning Adjustment.
The county already issued its zoning permit for the landfill last month. But area residents and the Labadie Environmental Organization are appealing that decision, saying the county went against its own regulations in issuing that permit.
Those regulations (see item 3.c., on pp.14-15 of this document) require that the base of a coal ash landfill be at least two feet above the "natural water table" at the landfill site.
Labadie Environmental Organization president Patricia Schuba said "intermittent contact" ― no matter how infrequent ― doesn't meet that requirement.
"Ameren has designed this landfill with full knowledge that it will be sitting below the water table in some portions of the landfill site," Schuba said.
Schuba said the county needs to revoke Ameren's permit. She said Ameren has two choices when it comes building the landfill: "They can redesign it at least two feet higher than the water table, or they can choose an alternate site which puts it away from water."
Schuba said building the landfill somewhere other than the floodplain of the Missouri River would be a better choice.
Ameren declined St. Louis Public Radio's request for an interview. But in a written statement, the company maintained that its landfill would be more than two feet above the "natural water table."
According to Schuba, that's because the company is defining "natural water table" to be the average groundwater level at the site. She said that calculation ignores what actually happens to the water table during wet years, when water levels in the Missouri River rise and groundwater levels in the floodplain rise, too ― high enough to come into "intermittent contact" with the landfill.
You can read all of Ameren's statement, here:
"Building this state-of-the-art landfill is the right thing to do for Ameren Missouri customers. It's also the responsible solution for protecting the environment. Under Ameren Missouri's design, the base of the landfill liner is more than two feet above the natural water table, which is in accordance with the proposed EPA guidelines and Franklin County ordinances. The staff of the Missouri Public Service Commission recommended approval of our Certificate of Convenience and Necessity (CCN). The Missouri Department of Natural Resources completed a detailed investigation and concluded this site is appropriate for the landfill. Franklin County’s independent registered engineer also reviewed the design and confirmed that the base of the landfill will be located more than two feet above the natural water table as required by the county’s ordinance. In addition, Ameren Missouri retained an independent engineering firm to determine the location of the water table, and that company also confirmed the base will be located more than two feet above the natural water table."
For now, it's up to the Franklin County Board of Zoning Adjustment to choose whose definition of "natural water table" to go by.
Patricia Schuba thinks that decision could take a while. She said she doesn't expect the Board to determine whether or not to revoke Ameren's zoning permit until the end of June.
After that, the losing side could appeal the Board's decision in circuit court.
Meanwhile, the landfill's opponents are pursuing other avenues to stop its construction.
Last week, the Labadie Environmental Group and others delivered about 3,500 petitions to Missouri Governor Jay Nixon's office, asking that he keep the Missouri Department of Natural Resources from issuing a construction permit for Ameren's proposed landfill ― the next step after county approval.
Schuba said she hopes Nixon will ask the state agency to wait to issue its permit until after the first federal regulations for coal ash disposal are finalized by the U.S. Environmental Protection Agency on December 19.
As written, those proposed regulations would require that coal ash landfills be built "a minimum of two feet above the upper limit of the natural water table."
Follow Véronique LaCapra on Twitter: @KWMUScience