THE second stage of the Water Corporation’s plan to replenish groundwater supplies has received conditional approval from the Environmental Protection Authority.
As part of the Groundwater Replenishment Scheme, it proposes to duplicate the existing advanced water recycling plant at the Beenyup Wastewater Treatment Plant in Craigie and build 12.8km of pipeline connecting it to recharge facilities in Wanneroo and Neerabup.
Wastewater treated to drinking-water standards will be transported through the pipeline to the two sites and enable up to 14 billion litres to be injected annually into the Leederville and Yarragadee aquifers.
This is in addition to the 14 billion litres already being injected through the project’s first stage.
The scheme is the first of its kind in Australia and it is anticipated that groundwater replenishment could supply up to 20 per cent of Perth’s drinking water by 2060.
The EPA’s report to the Environment Minister said 2.9ha of native vegetation would need to be cleared along the pipelines and 0.17ha of pine trees – the foraging habitat for Carnaby’s black cockatoos – would be removed.
The majority of the pipeline will be within the Yellagonga Regional Park, alongside the eastern edge of Lake Joondalup.
EPA chairman Tom Hatton said techniques would be used to keep the impact to a minimum.
“Some sections of the pipeline would be constructed using technologies such as microtunnelling or horizontal directional drilling to avoid the clearing of native vegetation in sensitive banksia woodland,” he said.
The Water Corporation also committed to rehabilitating areas of disturbed native vegetation and replacing any verge trees removed with native species.
The report said the two recharge sites were chosen to manage total replenishment and abstraction across the Gnangara groundwater system.
“The EPA…is confident in the predictions of the proponent about the low degree of risk posed to the superficial, Leederville and Yarragadee aquifers should the proposal be implemented,” it said.
It found the proposal was “environmentally acceptable” but recommended conditions, including ensuring no indirect impact to banksia woodlands within five years post-construction, implementing hygiene protocols, undertaking weed control, treating and managing acid sulfate soils, and minimising the effects to terrestrial fauna during construction.
Appeals can be made until June 12 at www.appealsconvenor.wa.gov.au.