Stoney Creek councillor Brad Clark wants the city to force the province's hand on expanding the protection area for the Eramosa karst by rezoning government-owned land to the east as open space.

He said Queen's Park is "playing games" by suggesting the city supports developing the area, even after council passed a unanimous resolution calling for its preservation.

The economic development and planning committee recently directed staff to study the possibility of rezoning the land to prevent development.

"Let the province be the ones to actually say, 'No we want to develop the land," Mr. Clark said.

"We froze the secondary plans (in the area)," he said. "To say that we want to develop it is slightly more than disingenuous."

The call for the municipal hardball comes as the Ontario Realty Corp. prepares to hold an open house this Wednesday as part of an environmental assessment on 87 hectares of land near the existing Eramosa Karst Conservation Area, most of it to the immediate east.

Mr. Clark and other karst supporters argue development will threaten the 73-hectare park's abundance of caves, sink holes, dry valleys and sinking streams.

Adding fuel to the debate is the re-emergence of a buried sinkhole on the ORC land near the corner of Richdale and Fairhaven drives.

Marcus Buck, a cave expert who helped convince the province to establish the karst park is not surprised the sinkhole resurfaced.

Unless properly re-engineered, such sinkholes can be expected to reappear because the park is only a small portion of the geologic formation, he said.

"If you look at the backyards (in the area), there are low lying depressions. I don't doubt for a second that they've been filled in over the years," Mr. Buck said. "To put it in perspective, the karst continues 10 kilometres to the east and several to the west," he said. "This (park) is only a piece of it and there's other issues to the west all the way to Upper Ottawa (Street) and beyond."

ORC spokesperson Bill Moore said the sinkhole is part of the assessment.

It has been fenced off and has a yardstick inserted into its centre.

"I'm not aware that it was filled in," he said. "The whole area is part of the review and that particular area, they wanted to protect and prevent people from entering into it."

In an earlier interview, Imshun Je, the ORC's environmental assessment coordinator, told the Stoney Creek News the study will consider expansion of the karst's buffer zone as "an option." But she acknowledged the focus is to prepare the land - located west of Second Road West between Rymal and Highland roads - for sale to developers because it is "surplus to government needs."

Mr. Buck said the report he co-authored on the karst took a conservative approach to protection because the entire area was slated for development. He supports the city's efforts to expand the park because recent development already placed fill in feeder areas and diverted water flows.

"The process of building housing is extremely complicated and there's a lot of issues," Mr. Buck said. "You've got a lot of priorities in there that are way above trying to worry about whether there's a karst there or not, whether it's a natural heritage feature," he said.

"You've got public safety, a whole bunch of things. My concern now is, they go to develop that, ultimately the preservation of the karst will not be at the top of the priority list."

The ORC open house takes place from 4 p.m. to 8 p.m. at the Hamilton Firefighters Drum Corps Banquet Facility, 175 Dartnall Rd. S.