Attorneys for Angelo's Aggregate want to revise their landfill application next week after several expert witnesses pointed out flaws in their calculations and design.
"It's based on new information that's come to light," said Linda Loomis Shelley, an attorney for Angelo's.
Angelo's is appealing the ruling last January by the Department of Environmental Protection to uphold the state's rejection of the landfill permit. Shelley announced the revision Friday as the parties wrapped up the third week of the appeal.
Doug Hanson, an attorney for Nestle Waters and the City of Tampa, objected to the last minute changes, but Administrative Law Judge Bram Canter said he would consider allowing them after he'd had a chance to review the new information.
"They're still trying to fix their settlement calculations," Hanson said. "We told them their grout plan was flawed, so now they want to change that. But it won't fix the fact that this is an unstable area."
Angelo's already had presented the bulk of its case. On Friday, Carter heard from geologist Sam Upchurch, one of the state's leading experts in sinkholes. He said site of the proposed landfill has so many depressions, or dimples, the surface resembles a "golf ball."
The landfill, if approved, would be four miles southeast of Dade City on land south of Enterprise Road. The site is near a construction debris landfill that is owned and operated by the Iafrates family, which initially applied for the residential waste landfill in 2006.
The case has drawn widespread opposition from Tampa Bay area cities, businesses and residents who fear the site's proximity to the Withlacoochee River and Green Swamp could contaminate the water supply, particularly if a there was a breech in the landfill liner.
"Our closest wells are two miles away," Zephyrhills City Attorney Joe Poblick said. "If there's a breech and the leachate gets into the water, we're done. There's no more 'City of Clean Water.' It would be catastrophic."
Upchurch said the proposed landfill site has significant sinkhole activity.
"It is unstable," he said. "We're not talking about unstable in the sense that sinkholes are opening up like popcorn."
But the number of depressions he observed had multiplied just in the last two years. And the landfill is in the recharge area for the Crystal Spring, the source for Nestle's Zephyrhills Water bottling plant and for the city of Zephyrhills, he said.
Karen Brodeen, an attorney for Angelo's, questioned Upchurch about a sinkhole that opened up on the edge of Hillsborough County's municipal landfill in 2011. She pointed out that Hillsborough's monitoring wells did not detect any contamination in the groundwater.
Upchurch said the two locations are not comparable. The Hillsborough sinkhole was triggered by excessive groundwater pumping by area strawberry farmers after an extended period of freezing weather.
The limestone in northeast Pasco County is far less stable, he said.
"Is it fair to say nobody can predict if there is going to be a sinkhole?" Brodeen asked.
"No," Upchurch responded. "That's why we use the term sinkhole risk."