Think Water Northern Rivers was contracted to install a recycled water and irrigation system at Ken Leeson Oval in Iluka on the north coast of New South Wales on behalf of Synergy Resource Management Pty Ltd. The Oval situated on Crown land, being under the care, control and management of Clarence Valley Council, was the second stage of the recycled water and irrigation project, the first stage of which involved Think Water Northern Rivers designing and installing an irrigation system on the local golf course.
Client: Clarence Valley Council
Principal contractor: Synergy Resource Management
Irrigation Contractor: Think Water Northern Rivers
Irrigation Designer: Edwards Irrigation Consulting
Scope of works
- Provide earthworks to shape sports fields and re-establishment of turf
- Install automated electric/hydraulic sprinkler system on sports fields
- Install tanks and pump station to supply pressurised recycle water for the irrigation system, as well as an independent pressurised groundwater supply for the cricket pitch.
- Automate recycle water tank fill
The primary water source for irrigating both the golf course and the oval is recycled water, which is supplied from the recently upgraded sewage treatment plant (STP). The recycled water is currently supplemented by potable water from the town water supply. The council expects that population growth in Iluka in the next few years will mean that the backup supply from the town’s potable source will not be needed to supplement the irrigation supply, and this increase in wastewater generated was allowed for when the sewage treatment infrastructure was upgraded.
One of the features of Iluka is that the coastal landscape where it is situated is extremely flat, so a pressurised sewage collection system was installed to efficiently transport waste to the treatment plant.
“A pressure sewer system has a small pump well with a submersible grinder pump servicing each property,” said Lee. ” The collection wells connecting to a pressure sewer reticulation network which transports the untreated wastewater to the sewage treatment plant.”
The tertiary treated recycled water produced by the STP is the primary water source for the irrigation system on the golf course and oval. Following treatment itis stored in a covered pond at the sewage treatment plant and transferred back to the two concrete tanks (located on their respective irrigation sites) to meet irrigation demand. Any surplus recycled water produced by the STP that cannot be stored either at the STP or in the Irrigation storage tanks can be fed into an environmental release system main that runs from the treatment plant to the river. The environmental release in the river only operates on an outgoing tide to ensure that recycled water can only be transported out to sea and not upriver. Since the Iluka sewerage system was commissioned in September 2015, the only time the environmental release has operated is for monthly testing and all other recycled water has been irrigated.
The Ken Leeson Ovalsite
The sports field is located within a residential area which presented some challenges for the works required. As the work’s brief included significant laser levelling and re-shaping of the field, with up to 400mm of topsoil being removed in some areas dust issues and wind erosion, were a concern.
As the field was primarily a sand-based substrate, Think Water worked with the principal contractor to minimise the amount of time the field would be stripped of vegetation. To this end mainlines and laterals were installed before stripping turf and laser levelling. To achieve the specified minimum 450mm final depth of coverage over the pipework, each sprinkler position was surveyed and marked with cut and fill levels documented. Trenching was completed based on final finished grade ensuring minimum cover of 450mm was achieved after final levelling. Sprinklers were fitted after the levelling process, and before the fields were re-turfed.
The field’s proximity to other sporting facilities and entertainment venues also meant that foot traffic was going to be an issue both in terms of potential disruption and safety concerns. To overcome this potential hazard, the entire field was cordoned off using security fencing for the duration of the installation.
The site was identified as having significant aboriginal cultural heritage and so it was important to work with the principal contractor and local council to meet compliance criteria to ensure that nothing of cultural significance was disturbed.
The Irrigation System
Like most councils, Clarence Valley is keen to be able to remotely manage the irrigation systems it is responsible for. Being a rural council, this means having a control system that networks irrigation systems in a variety of towns and townships, from Grafton in the south to Iluka 80 km to the north.
To achieve the long term goal of central control with remote management, Think Water Northern Rivers initially installed a Hunter ACC2 controller to manage the automation. This allows the system to run ‘stand-alone’ however readily integrates with Hunter Integrated Management & Monitoring Software (IMMS 3.0) planned for the future. This will give the Council total remote control over each of the controller’s functions with flow monitoring, weather sensing and soil moisture monitoring already installed, the IMMS 3.0 system will access this data for future reporting capability.
Sprinklers installed were Toro 640 hydraulic valve in head. These were selected for the project due to their exceptional quality and long term durability. The system was specified as hydraulic to ensure electrical damage due to lightning strike was minimised and to mitigate the risk of nuisance fouling and potential unreliability of solenoid valves that can result from algae and other contaminants suspended in recycling water. Pilot water supply used to actuate the sprinklers is supplied from a boosted potable water source which is chlorinated and filtered, therefore maximising the reliability of the system.
During this project, access to the site was restricted for several weeks due to the unprecedented bushfires. Iluka was isolated for an extended period. Immediately after the bushfire closures, Iluka experienced 800mm of rainfall in the following three months. Luckily, the sandy soils allowed work to continue between downpours and the project was completed and commissioned by the end of April.
“A well-run project delivered safely, on time and a budget doesn’t just happen by itself,” says Lee.”It’s all about planning and establishing an effective communication program that ensures all stakeholders are kept informed and that everyone’s expectations are met or exceeded. We always plan to avoid issues happening during the project, but invariably issues turn up uninvited and unannounced! So, good project management is also about dealing with issues quickly and efficiently as soon as they arise, making sure the quality of the job is not compromised and that all stakeholders including the client are kept in the loop. Put simply, it’s all about teamwork and a collaborative approach to achieving a great outcome.”
Synergy Resource Management was engaged by Clarence Valley Council as the principal contractor for the project. The Site Project Manager, Greg Linsley-Noakes said of Think Water Northern Rivers and their project team:
“Now that the project is drawing to an end, I would just like to say that it has been a pleasure dealing with Think Water and the team
- They have been very professional
- Always compliant with site rules
- We have worked together to minimise variations and worked with the scope of works to meet a very tight budget
- The attention to detail is excellent and the pump station is a work of art. We have got a great result with the budget we had
- Your team have even come down here in their own time on weekends to help me water the turf when things didn’t go to plan
- Your attitude has always been one of the bottle half full not half empty and you have been a pleasure to work with.
“We have had our challenges with fires, floods and COVID 19, but your guys battled through these issues and got the job done.”