Q. How do you bore 1km of pipe through central Melbourne?
For a number of years, City of Melbourne has harvested storm water from the Oak St Wetlands in Parkville – just North of the big yellow “cheesesticks” on the Tullamarine freeway. This involves millions of litres of storm water being captured, treated and then pumped through the Royal Park precinct in Carlton, irrigating thousands of acres of trees, plants, grassland and sports-fields. A fantastic initiative, as this storm water would otherwise be wasted.
In late 2019 City of Melbourne had the great idea to extend this recycled main water pipe, which currently terminates just north of Princes Park, down through the park. A fantastic initiative, as it will allow the irrigation of trees, plants and grassland in Princes Park using reclaimed stormwater. However incredibly tricky because it involves getting more than 1km of continuous pipe underground without impacting the magnificent trees and plants that run alongside Royal Parade.
The answer was to bore the entire length of pipe- 1,010m to be exact.
City of Melbourne worked with a series of arborists and other experts, who then engaged Century Rain to develop a plan to bore this mammoth length of pipe all the way along Royal Parade, past the Carlton Football ground, to the Crawford oval tanks (140,000 Litres each) at the south end of Princes Park. See plan of 1km pipeline.
If you know the area, you’ll know that it’s one of the busiest parts of Carlton. So whilst maintaining the structural integrity of the invaluable tree roots was paramount, the Century Rain team also had to contend with:
- Traffic and pedestrians
- Median strips
- Power, Gas and Telstra lines
- and a long forgotten light rail system containing bluestone which had been buried for many years.
The underground pipe being bored was 160mm in diameter, reducing to 90mm as it made it’s way south. It will deliver around 6 litres/second into the water storage tanks, to be used for irrigation.
Because Century Rain has years of experience in boring irrigation pipes, this delicate job was wrapped up in less than five weeks. If you’re not familiar with boring, otherwise known as Non Destructive Digging, it involves a drill head being electronically guided under the surface, with a pipe then pulled back through the bore hole, with almost no disruption to the surface of the ground. All achieved in accordance with City of Melbourne’s strict requirements, including working with a series of arborists to ensure the structural integrity of the trees were not affected.
A fantastic initiative by City of Melbourne, who in 2019 joined more than 1400 jurisdictions around the world to declare a climate emergency. A significant part of this commitment included increasing the councils already large investment in stormwater harvesting. This project is a great example of that, as it not only saves 1000’s of kilolitres of water each year, but also reduces the stress on the city’s existing storm water system.
Look out for a greener and healthier looking Princes Park later this year.