The Hamilton Conservation Authority is calling on the McGuinty government to more than double the size of Stoney Creek's Eramosa Karst park.

Directors last week unanimously passed a resolution opposing the Ontario Realty Corporation's plans to sell 80 hectares of land to the immediate east of the park to home builders.

The authority has already assumed ownership of the 73-hectare park from the ORC and is offering to do likewise for the neighbouring land, whose creeks feed the karst's caves, sinkholes and underground streams.

In pushing for a "strong stand," Stoney Creek Councillor Brad Clark dismissed the reliability of ORC technical studies released in June that argue a storm water management pond can substitute for three feeder streams.

Part of an ongoing environmental assessment of the housing plans, the studies are suspect, he said, because the provincial agency's central mandate is to sell land to bolster government coffers, not protect the environment.

"They would obliterate those streams," Mr. Clark said.

"Without the streams, the caves are going to change. We can't even predict the water flows because it's karst land. It's percolating through," he said.

"Now you put housing in there, it no longer percolates through. (The land) becomes impervious and (the water) goes to the sewers and is redirected to the storm water management pond and collected in off the roads, which is not always friendly to the environment, and is then flushed into the caves."

Director Jim Howlett said the authority must speak out "as advocates for the land" because the connection between the two sites crosses political and geographic lines.

"Obviously, anybody would say that it would be wrong for us cut off a feeder stream from a trout pond," he said.

"They would say that is throwing the baby out with the bath water. I think that this is just as obvious."

The decision to lobby Queen's Park came after a presentation by members of the citizens group Friends of the Eramosa Karst, who urged the authority to be proactive in preserving the feeder area.

They said only the ORC and its engineers believe the land -- located east of Mount Albion Road between Rymal and Highland roads -- can be developed without harming the karst.

"Engineers also said the Titanic wasn't going to sink and down it went. They said it couldn't happen," said Rita Giulietti, the group's communications coordinator.

"We're being told by the engineers that damage will not happen, that the mitigation will be sufficient to preserve the karst in its natural state. We just don't buy that."

Authority chair Chris Firth-Eagland said he shares concerns about the effects of development, having seen the karst in action during a rain storm.

"Those feeder streams and feeder areas that keep the karst alive are absolutely essential to its dynamic future," he said.

"It can be a dead, stale piece of property or it can be dynamic and evolve throughout time as it has, and that's the beauty of it," he said. "Management of natural systems isn't just the biota that's involved. Here we have a chance to understand that it's also the land."

The authority has hired local cave expert Marcus Buck to review the ORC studies and is expected to submit formal comments by the end of this month.