Yarralumla residents are angry about what they say is a planned massive flattening out of the landscape behind the suburb, removing as much as seven metres from the tops of the forested ridges between Government House and the Brickworks for the new housing precinct.
Yarralumla Residents Association president Marea Fatseas said the plan would devastate a huge area and amounted to "environmental vandalism" as the government imposed a grid design for the new Brickworks housing development.
A report from consultants SMEC envisages reducing the ground height by between two metres and seven metres in the area of the site near the Brickworks across the Dunrossil Drive area and towards Cotter Road. Most of the 245,000 cubic metres of soil taken from the ridges would be used to fill in lower parts of the site, near the centre of the new suburb and towards Adelaide Avenue.
But the Land Development Agency said the amount of cut material required was still being determined and was "likely to be significantly less than the figure estimated in the report".
"The intent is to retain as much of the natural topography of the area as possible within the construction and planning constraints," deputy chief executive Dan Stewart, said.
Dunrossil Drive leads from Cotter Road to Government House, the Governor-General's residence. The end of Dunrossil Drive that connects with Cotter Road is to be chopped off, with a new "Brickworks Road" taking traffic off Cotter Road instead.
Ms Fatseas said the plan was to "cram" more than 3000 people into the new 1800-dwelling suburb, which would double the population of Yarralumla. The density of people in the new area would be about three times the density in the rest of Yarralumla, she said.
She raised concerns about the grid pattern proposed for the new roads, which she said was out of keeping with the existing suburb.
And she said the residents had counted on the park alongside Denman Street to provide a buffer for sound and dust during construction, but it looked from the landscape plan as though the trees there now would all be removed and the park designed from scratch. "It means effectively you will be left with a dust bowl for up to 10 years," she said. "It will be ground zero. We thought there would be a bit of a buffer between the existing suburb ... but we didn't realise they were planning to get rid of everything."
She was "astonished" at the destruction of heritage in the Dunrossil Drive area and said the road, the elms that lined it and the remnants of Westbourne Woods were all heritage-listed. "We can't believe they're planning to demolish the ridges on either side of Dunrossil Drive," she said. "We're astonished that if they can get away with that in an area that's got all this heritage attached to it, well nowhere is safe really."
Mr Stewart said the decision about earthworks would balance "cost, landscaping, constructability, sustainability and community input as well as engineering".
While the new development had higher density than the existing suburb, that was because of medium density homes around the brickworks, and higher density near Adelaide Avenue and Deakin.
Ms Fatseas has called Chief Minister Andrew Barr and Greens Minister Shane Rattenbury to voice her concerns, and residents have set up a working group to come up with new ideas for the area and to put their case in the lead-up to the 2016 election.