The Environmental Protection Authority has recommended the Tonkin Highway upgrade can go ahead, subject to a plethora of environmental measures to protect adjacent wetlands.
The Tonkin Highway Grade Separated Interchanges project proposes a widening of a 4.2 kilometres section of the major freight route from four to six lanes, with a single fly-over at the Hale Road intersection, and an interchange at Welshpool Road.
It would impact a stretch from south of Roe Highway to 1km north of Kevlin Road.
In its report, submitted to the minister on July 31 and released publicly today, the EPA highlighted the challenges of continued development on the Swan Coastal Plain.
It raised concerns over whether environmental objectives could be met when cumulative effects had already been “significant”.
EPA deputy chair Lee McIntosh said Main Roads was asked to identify avoidance and mitigation measures in addition to those outlined in its original proposal.
“The proponent responded by amending the proposal three times and ultimately reducing the development envelope by 20 hectares,” Ms McIntosh said.
“And the conditions proposed by the EPA will require maintenance of the hydrological regime and water quality of conservation significant wetlands including the Greater Brixton Street Wetlands.
“To counterbalance potential impacts, the EPA is also recommending a combined offsets approach which includes land acquisition, threat abatement and restoration, and research in GBSW knowledge gaps and hydrological processes.”
The report called for a regional environmental protection framework which considers cumulative effects and included provisions for restoration.
The development comes after years of work to revise the plans following public feedback and is jointly funded by the federal government ($293 million) and the state government ($73 million).
The report is open for public comment and appeals until August 26.
