Why is this work taking place?
As Perth continues to experience the impacts of climate change, the decision was made in July 2016 to expand our Groundwater Replenishment Scheme.
This will provide better certainty for Perth's water supplies, seeing the Scheme's capacity increase from 14 billion litres per year to 28 billion litres a year.
We have been working closely with the Department of Water and Environmental Regulation to identify locations suitable to recharge this water, with the final sites selected at the pine plantation in Wanneroo and at a site further north in Neerabup.
How were the recharge sites selected?
Potential sites were chosen in consultation with the Department of Water and Environment Regulation. The location of these sites has largely been informed by studies undertaken by the Department that looked at how much water can be extracted from Perth's deep aquifers without impacting their long-term sustainability.
How was the pipeline route selected?
The pipeline is required to convey the water from the Advanced Water Recycling Plant in Craigie to the two offsite recharge sites in Wanneroo and Neerabup. The pipeline route was selected with a number of considerations in mind, including impacts to the community, environment, safety (of people constructing and maintaining the pipeline), constructability and cost.
What will the work involve at the recharge bore sites?
At each bore site, we will be installing four bores, including two recharge bores and two monitoring bores, and associated infrastructure.
The installation of the bores will involve drilling and will take approximately four months, split over two, two-month periods. During this time, 24/7 operation will be required. This is required due to the depth of the bores. If we work during the day only, there is a risk of the bore collapsing, which would increase safety risks for the project and extend the length of the project significantly.
At a later date, we will install the associated infrastructure for the bores, including a recharge pump building, a switch room building, a balance tank, a High Voltage metering unit, switchgear and transformers, and an emergency overflow sump.
What will the work involve for the recharge pipeline?
Most of the pipeline will be constructed via open trenching, meaning we will be digging up roads/ground. The pipe will then be laid in the ground and covered back over. Through built-up areas we expect to install about 20 metres per day. As sections are complete we will be reinstating disturbed areas to their previous state.
The majority of work will be completed on weekdays between 7am and 7pm. Some weekend work may be carried out to shorten the overall time we are onsite.
What impacts do you expect near the bore sites?
Prior to undertaking the work we conduct noise monitoring to ensure we know baseline noise levels in the area.
We will continue to monitor noise levels during work and will ensure all noise-generating equipment has noise control in place, including noise blankets and the use of noise barriers within and around the perimeter of the site.
As there will be increased traffic in the area from the work, we will also be putting in place traffic management, including the use of people to manage traffic flow.
We will aim to position any lights required on site for evening/night work in such a way that they do not impact surrounding residents.
Will the work to install the pipeline be noisy?
Construction will involve some noisy work, including road cutting (where required), excavating and compacting.
I live along the pipeline route, will I still be able to access my property?
Access to impacted properties will still be available, however, there may be some minor delays if we are completing works directly in front of your house. If this is required, we will provide you with at least one weeks' written notice and another 48 hours' verbal notice.
Will there be road closures when the pipeline is being installed?
While we will aim to maintain access to roads at all times, there may be times when we will need to temporarily close a road. If this is required, we will provide you with at least 48 hours' notice. Traffic management will be in place at all times to ensure the safety of road users and pedestrians.