Critical upgrades from Seqwater are designed to ensure ongoing safety and water security in south-east Queensland for years to come.
The Queensland Government is investing $69 million into strengthening works for the North Pine Dam wall as part of Seqwater’s Dam Improvement Program.
Seqwater Interim CEO, Will Harpham said that the North Pine Dam Improvement Project is focused on ensuring the dam continues to operate safely in extreme weather events and provide water security for generations to come. The staged strengthening work will also bring enhanced safety benefits and support the major dam upgrade planned for Lake Samsonvale.
“While planning for the major dam upgrade continues, Seqwater has identified an opportunity to undertake early strengthening work to the dam wall,” Mr Harpham said.
“The staged strengthening work will deliver enhanced safety benefits ahead of further upgrades being assessed as part of the North Pine Dam Improvement Project.
“While North Pine Dam continues to operate safely, dam design and engineering standards, along with knowledge of weather and flood risks, have evolved since it was constructed in 1976.
“The strengthening project will see more than 60 post-tensioned anchors installed into the dam wall. Ranging from 42 to 94m in length, these anchors will add up to approximately 100,000t of weight into the dam wall to further strengthen it.”
SMEC was awarded the contract for detailed design on the strengthening project, with construction work expected to commence on-site in 2025.
Geotechnical drilling activities were completed in April 2024 as part of the pre-planning and investigation phase to inform the options analysis for the major upgrade. An options analysis is currently being completed for the North Pine Dam Improvement Project to carefully assess long-term options for increasing the dam’s capabilities.
The project will be the first major upgrade of North Pine since it was built almost 50 years ago. Constructed in 1976, the dam, also known as Lake Samsonvale, is built across the North Pine River, 5km upstream from Petrie, which is about 26km north of the Brisbane.
One of south-east Queensland’s gated dams, alongside Wivenhoe and Somerset, North Pine is an important part of the SEQ Water Grid, which allows Seqwater to move treated drinking water around the region.
The primary purpose of North Pine Dam is storing water for the people of nearby North Brisbane and Moreton Bay; however, the dam is operating with a reduced full-supply level while the improvement project is underway.
This is an industry-standard practice to manage dam safety and, according to Seqwater, demonstrates its commitment to the ongoing security of infrastructure. It does not significantly impact long-term water security. The fact that south-east Queensland has a safe, reliable and resilient water supply system stemming from careful and ongoing water security planning and a diverse asset base allows Seqwater to supplement supply in a timely manner as needed.
Bringing dams into the modern day
Dams are long-life assets that require continual assessment, monitoring and maintenance. While Seqwater dams were built to stringent international safety standards, many were built in the 1960s and 1970s, some even earlier.
Methodologies and data used to estimate extreme rainfall events have significantly improved in recent times and industry engineering standards and our understanding of dam safety risks have also progressed since the dams were originally built. There are multiple dam upgrades occurring across Queensland to meet modern engineering standards and to comply with the dam safety requirements outlined in the Water Supply Act 2008.
Through its Dam Improvement Program, Seqwater is investing in south-east Queensland’s dams to ensure ongoing safety and water security. The bulk water provider has delivered 13 such upgrades since 2008, including Leslie Harrison Dam at Capalaba, Sideling Creek Dam north of Brisbane, and Ewen Maddock Dam on the Sunshine Coast.
As part of the next stage of upgrades, early works are underway on the Lake Macdonald Dam Improvement Project, geotechnical works are underway on Wivenhoe Dam to inform the options analysis for its upgrade, and Somerset Dam has received more than $500 million in funding approval as part of the first stage of the Somerset Dam Improvement Project.
Early works for Somerset Dam
As part of Seqwater’s Dam Improvement Program, Somerset Dam is also being upgraded to meet modern engineering and design standards.
The Queensland Government announced in June more than $500 million in approved funding for investment into the early and enabling works at Somerset Dam.
Seqwater is pleased to be planning a range of early and enabling works to support future construction on the major dam upgrade planned at this site.
“The early and enabling works will broadly include the removal of the spillway (radial) gates which are nearing the end of their service life, replacement of eight sluice gates, geotechnical investigations, temporary and permanent access road works, and the augmentation of its original drainage curtain,” Mr Harpham said.
“The works are required to be completed irrespective of the final design option for the Somerset Dam Improvement Project, which is currently being considered as part of the detailed business case stage. The early and enabling works are expected to commence on-site in 2025.”
Featured image: the North Pine Dam. Image: Seqwater
