Wetlands of international importance are one of seven matters of national environmental significance that must be assessed under the Environment Protection and Biodiversity Conservation Act.
The Lower Hunter’s 3000-hectare wetland area was declared a site of world significance on the Ramsar register in 1984. It includes the Kooragang nature reserve and the Shortland wetlands centre.
The Commonwealth’s assessment, which will be done via a bilateral agreement between the state and Commonwealth governments, will examine the likely effect of the dam on the region’s wetlands.
Mr Garrett will then make a determination on the project.
Newcastle Wilderness Society campaigner Vanessa Culliford said the dam would have a major impact on Lower Hunter wetlands.
“The Williams River has the most diverse and intact aquatic biotic communities in the Hunter Valley and runs into Ramsar wetlands; why would we want to allow that to be destroyed,” she said.
Greens MP John Kaye said Mr Garrett’s intervention represented a significant setback for the State Government that recently used its controversial 3A planning powers to declare the dam critical infrastructure.
“While the NSW Government is trying to fast-track approval, Peter Garrett has thrown up a massive speed hump,” he said.
“This is bad news for Premier Nathan Rees and his Water Minister Phil Costa. They now have two fights on their hands, defending both the environmental impacts and need for the water.”
Ms Holmes said Hunter Water welcomed the Commonwealth’s involvement.
“We believed that referring the project for consideration by the Commonwealth was a prudent approach for a major infrastructure project,” she said.
“We welcome the Commonwealth’s involvement in the process, we look forward to working with them.”
No Tillegra Action Group spokeswoman Sally Corbett said more than 100 public submissions had been sent to Mr Garrett’s office opposing the dam.