Veolia is close to completing the installation of a 5.4 km dual pipeline which will provide a short-term solution to the issue of rising groundwater in greater Bendigo, regional Victoria. The Bendigo Groundwater Project, which has been funded by an AU$29.77 million injection from the State Government, is being managed by the local water authority Coliban Water.
At one point in history, Bendigo was considered one of the most prosperous gold mining regions in the world. Between 1851 and 1954 more than 700,000 kg of gold was mined from the Central Deborah Gold Mine alone. This equates to approximately AU$30 billion in today’s economy. However, mining in the Bendigo region was all but extinguished by 2011. As a result, groundwater levels in the area have gradually recovered to natural levels, wreaking havoc for the community, the environment and the town’s vital tourist economy.
The groundwater contains high levels of salinity, arsenic and other heavy metals, as well as hydrogen sulphide gas which exudes an odour which has been likened to rotting eggs. The issue is so significant within the wider Bendigo community that Coliban Water, with the support of the Victorian Department of Environment, Land, Water and Planning (DELWP), was forced to act quickly to institute a short-term solution, while a more permanent solution can be formulated.
“The government was looking for an instant solution to resolve the issue and released an initial expression of interest to try and get interested parties to come up with a plan to resolve the issue,” says Coliban Water General Manager Water Quality Performance and Regulation David Sheehan.
“It became clear through that process that Coliban Water was well positioned to manage the work on behalf of the state. We recognised that we had an obligation to support the community, so we were happy to work with the government to deliver a solution.”
Veolia’s solution was the trenchless installation of the refurbished pipeline that will connect a new groundwater treatment plant – located at the New Moon Mine in Eaglehawk – to a brine storage lagoon at Coliban Water’s Bendigo Water Reclamation Plant in Epsom. At present, groundwater from the Central Deborah tourist mine has been pumped to the New Chum line of workings via a mineshaft, with no water being pumped to the Woodvale evaporation ponds.
Mr Sheehan says Veolia’s solution stood out because it limited disruptions to the community, protected the fragile environment, but also didn’t require local government approval meaning construction could start immediately.
“I think the advantage of Veolia’s solution was its use of Trenchless Technology. The time frame, the minimised disruptions to the community, and the fact that it didn’t cause any impact to the visual amenity of the area, meant that it was the best outcome for the community and Coliban Water,” he says.
Veolia Market Development Manager Network Services Ziad Bushnaq, who took the lead during the tendering process, says as soon as he was across the issue – and its urgency – he immediately started designing a plan based on no-dig methods.
“During the tendering stage, we thought the best solution was to construct the pipeline using a trenchless technique, because it would mean it wouldn’t require a council planning permit,” he says.
“During the construction stages of a project, any activity that impacts vegetation can trigger a planning permit, therefore causing stoppages or delays. Planning permits can sometimes take as long as 8–12 months for approval, Coliban Water simply didn’t have that time. Another benefit of our design was bore more than 200 m stretches with only two shafts, as opposed to digging a trench the length of the pipeline.
“We also would’ve had to disturb the footpath, nature strip, the road and its crossings, which would’ve disrupted the surrounding community. And then there are the problems associated with traffic management,” says Mr Bushnaq.
Veolia subcontracted local HDD specialist R & R McClure Excavation to install the pipeline. Three drilling crews have utilised directional drills to average 200 m per machine per week.
It executed continuous bores between 180-260 m in length, through a range of geology, including clay, sandstone and quartz. R & R McClure was also to use a customised dry suction vacuum excavation truck to locate utilities ahead of the HDD as it progresses.
Project Manager Kane Walsh, whose responsibilities have included client liaison and developing the construction program, became involved in the project once Veolia had been awarded the contract. He says he has been involved in projects with HDD at their foundation in the past, adding that it was a proven technology for reducing environmental impacts.
“HDD results in less environmental impact, less disturbance to the whole community, and there are less resources required. So far construction has been smooth sailing. The council have been on-board the whole way – they were included and a part of the whole planning process – and Coliban and the DELWP have been very much aware of the process and what is has involved. The biggest hurdle for us so far has been other services in the ground that have not been catalogued properly,” says Mr Walsh.
“That includes the thousands of abandoned mineshafts undisturbed underneath Bendigo which have never been surveyed. So, as well as vacuum excavation we’ve also used electronic detection products, like geographic information systems (GIS), and Dial Before You Dig to ensure we don’t encounter anything that might cause disruptions to construction.”
At the time of writing, construction on the short-term solution – which should keep the groundwater issue at bay for a minimum of four years – was expected to be completed by June, becoming operational in July 2017. Mr Bushnaq says he expected all stakeholders, including Coliban Water, to be satisfied with Veolia’s work on the project, opening up the possibility of the two working together on a permanent resolution.
“Once we have completed the project safely and with the quality that it requires, I think Coliban Water will be impressed by the final product, which opens up the possibility of us working together again in the future. Veolia is not only a network entity but also a treatment company, so we would definitely be interested in tendering for the permanent solution to Bendigo’s groundwater issue,” Mr Bushnaq says.
This article was featured in the June edition of Trenchless Australasia. To view the magazine on your PC, Mac, tablet, or mobile device, click here.
For more information visit the Veolia Water Technologies website.
If you have a project you would like featured in Trenchless Australasia contact Assistant Editor Nick Lovering at nlovering@gs-press.com.au