In the centre of a shimmering expanse of water in Knoxfield, a duck with a distinctive blue beak performs an abrupt deep dive, sending ripples across the surface.

Lake Knox, as it’s called by locals, is a 1.6 hectare dam which thanks to its native plants – including rare species – is home to a range of wildlife including the endangered blue-billed duck.

A blue-billed duck in Lake Knox Credit:Eddie Jim

But local residents and environment groups say this tranquil habitat is under threat from plans by government authority Development Victoria to partially fill in the lake and replace it with a wetland as part of a new housing development.

They say the consultation process for the plan has been a sham with the community invited to join a “wetlands working group” – but only on the understanding the loss of the lake was non-negotiable and they would not be able to speak to the media.