A small but determined group of people met for the first time at the Central Experimental Farm's observatory Saturday morning, hoping to grow their ranks and spread their message that a new Civic hospital complex should be built at Tunney's Pasture to avoid losing trees and green space.

The Ottawa Hospital's search for site to build a new hospital to replace its nearly 100-year-old Civic campus has been controversial.

The first proposed site was the farm right across Carling Avenue, which was slammed by activists and researchers.

That was scrapped when the Liberal government restarted the process and chose the Tunney's Pasture government complex, which was rejected by the hospital.

Finally, there was a third site, billed as a compromise: approximately 20 hectares at the eastern edge of the farm that aren't used for research.

The proposal, which hasn't been officially approved, quieted much of the criticism of the original farm proposal, but the group of 10 to 15 people who gathered at the property in question said they won't let the hospital be built without a fight.

"This is our very special national land. It's a [National Heritage Site]. How dare they even think about this?" said organizer Maggie Biesterfeld.

'Insane' decision to build there

Biesterfeld said the hospital should be built at Tunney's Pasture, which was the NCC's top choice. She said that site is more appropriate since it's already developed, has lots of parking and will have a light rail stop next year.

"We would definitely like [the farm] preserved as a national treasure," she said.

"This is our Central Park, our Hyde Park. This is our spot, and we're losing all our green space so rapidly in this city."

"This is the entranceway to the farm, it surrounds Dow's Lake," said former city councillor and mayoral candidate Clive Doucet at the rally.

"If they build this institution here, Dow's Lake will be a little puddle of water surrounded by large buildings. It's already moving that way along Carling Avenue… it is an insane decision and I want to know who did this."

Clive Doucet Ottawa

Former Ottawa city councillor Clive Doucet was at a rally against a new hospital on the Central Experimental Farm, saying he doesn't understand why Tunney's Pasture was chosen, then cancelled as a location. (Andrew Foote/CBC)

Nothing finalized

The Ottawa Hospital and National Capital Commission hadn't responded to a request for comment on these issues on Saturday.

The Hospital's website says it's committed to a "meaningful, inclusive and transparent" public consultation on a new hospital, with more consultation planned once the federal cabinet approves a location.

Ottawa's mayor and the provincial and federal politicians for the riding that includes the farm signed a letter to federal Heritage Minister Mélanie Joly the day this latest site was announced that said the site protects the farm's green space.

Leslie Maitland, one of the leaders of the campaign against the originally-proposed site on the farm, said in an email Saturday while she's disappointed the hospital could be built on the farm instead of Tunney's Pasture, it's a compromise that protects the farm's science, heritage and green space as much as possible.

The goal is to open a new hospital by 2026.

NCC Site 11 - Sir John Carling Building

The approximately 20-hectare parcel of land includes the site of the former Sir John Carling building, which was demolished in 2014. (National Capital Commission)