Spanning six years and five major projects, Unitywater’s $30 million upgrade of the greater Caloundra area’s sewerage network culminated late last year as construction of a new 10m diameter and 10m deep sewage pump station at Duck Holes Creek was completed. With the only pump able to meet the varied discharge head requirements of the pump station manufactured in Europe and a long procurement time expected, pre-planning was vital to ensure the equipment arrived at the right time for the contractor to install without delay.
With the population in the Caloundra area continuing to grow, the area’s sewerage network needed to be upgraded to meet the expanding needs of the community.
Unitywater Acting Executive Manager Sustainable Infrastructure Solutions, Amanda Creevey, said, “The purpose of the upgrade was to improve the capacity and efficiency of the sewerage network and manage sewage flows to cater for the growing communities of Caloundra, Pelican Waters, Little Mountain, Golden Beach and Bellvista.
“We also had to consider the new Caloundra South (Aura) development and ensure we had the infrastructure in place to service the early stages of the development.
“As well as the new pump station, we upgraded 2.5km of sewerage pipeline with a new 900mm diameter pipe. Construction was completed using two horizontal directional drills, with one being the longest horizontal directional drill of its kind in Australia.
“Constructing the pipeline in this way minimised the impact on the environment and community.
“The new pump station allows us to better manage flows in extreme wet weather events and minimises any overflows into the Pumicestone Passage.”
Designing and constructing the pump station
During the design stages of the project, four options for the Duck Holes Creek Pump Station were considered, with the final design chosen as it allowed Unitywater to maximise the life of its assets by re-using the existing 10m-deep wet well that had been constructed in the 1990s.
“One of the challenges with this project was managing sewage flows, as the construction was carried out in stages,” Ms Creevey said.
“We were able to take parts off-line while construction works took place, while still having an operational pump station.
“Another challenge was considering the logistics of the upgrade, particularly the size and weight of the three new pumps, which each weigh three tonnes. We had to keep this in mind for future access and maintenance.”
Pump selection and procurement
Ms Creevey said pre-planning was very important during the procurement stage, as Unitywater knew which pumps were needed when the project was designed. However, the pumps had a particularly long procurement time as they were manufactured in Europe.
“In order to reduce the procurement time for our contractor during the construction phase, we purchased the pumps early and transferred them to our contractor when the project began. This allowed us to reduce any unnecessary delays,” Ms Creevey said.
“In this scenario, the chosen pump was the only one that met our requirements for this project. This pump station delivers into a common rising main that extends approximately 9.4km to the sewage treatment plant.
“This rising main also receives inflows from five other pump stations, therefore discharging head varies depending on flows from other contributing pump stations. It was critical that these pumps were able to operate safely for the full range of contributing flows from these pump stations.
“The new pumps were tested to ISO 9906 Grade 1B, which is the European equivalent to the specified Australian Standard. The pumps were manufactured and tested in Europe.”
Ms Creevey said maintenance and repair schedules are vital for all of Unitywater’s assets to ensure they operate efficiently and meet their expected service life.
“The pump station is on our annual maintenance program, and each pump is inspected and serviced twice per year.”
Decorating the pump station
As part of Unitywater’s Reconciliation Action Plan, the Duck Holes Creek Pump Station was given a bright and contemporary facelift through a highly creative and collaborative community artwork process involving local Aboriginal emerging artists. The initiative formalised the utility’s commitment to provide opportunities for Aboriginal and Torres Strait Islander people and celebrate their culture in the areas it operates.
“Local artist Bianca Beetson was commissioned to work together with members of the Kabi Kabi community to design and paint the artwork,” Ms Creevey said.
“This site has significant cultural heritage as it was one of the last functioning Aboriginal camps on the Sunshine Coast, and was still operating in the early to mid-1900s.
“The design reflects the ancient and sacred connection of Indigenous people to the Duck Holes Creek area and the Sunshine Coast region more broadly.
“The artwork is spectacular and has really helped brighten up our new pump station.”