From In My Community:
It would be hard not to notice Water Corporation construction work in the Yellagonga Regional Park along Wanneroo Road, Woodvale.
The sewerage line will go from Ocean Reef Road under Whitfords Avenue and Hocking Road to Gangara Road.
Friends of Yellagonga Regional Park committee member JOHN CHESTER contributed to this piece to allay any fears about the project’s environmental impact.
In this $17.1 million project, the Water Corporation is installing a gravity-fed sewerage line to increase the capacity of the Wangara Industrial Estate and the rapidly expanding suburbs to the east of Wanneroo Road.
Proper planning has ensured most earthworks occur in degraded areas of the park so the environmental impact will be minimised.
Where the pipe passes under main roads or near housing, trenchless tunnelling technology will be used.
The estimated area of disruption is about 4ha but under an agreement between the Department of Environment and Conservation and the Water Corporation there will be a two-for-one environmental offset, with the Water Corporation rehabilitating an area of 8ha over four sites.
A $1.45 million contract for the rehabilitation work has been awarded to Natural Areas Management Services, which will spend at least three years removing invasive exotic plant species and planting up to 300,000 plants in designated areas.
Where possible, the plants will be local provenance, grown from seeds collected from within the park, and the Friends of Yellagonga Regional Park nursery expects to provide some of the plant stock.
One other issue of concern during excavation is potential acid sulphate soil.
Any soil profile containing iron sulphide when exposed to the air for more than 48 hours is likely to oxidise and form sulphuric acid, a major environmental hazard.
With this in mind, the Water Corporation has guaranteed that exposure time will not exceed 18 hours.
Any indication of acid in de-watering holding ponds will be neutralised with stockpiled crushed limestone.
The limestone access road used for construction work will remain after completion and will provide the base for a dual-use pathway which is planned along the eastern side of the park.