Paradise Dam new dam wall concept. Image courtesy of Sunwater

Sunwater has announced it is set to commence planning for the construction of an entirely new wall at Paradise Dam. This decision comes in response to expert recommendations that the existing dam wall, plagued by numerous issues, cannot be effectively repaired or reinforced.

The existing dam, now considered safer at its current lower supply level due to the essential works project undertaken by Sunwater, will persist in its reduced state until a new wall is erected. Sunwater's recommendation to the Government is clear: the dam wall must be wholly replaced.

The Queensland Government, committed to restoring the full water supply, has endorsed this proposal. The Honourable Glenn Butcher, Minister for Regional Development and Manufacturing and Minister for Water, emphasized the importance of a new dam wall meeting stringent safety criteria and serving the community for at least a century.

“A new wall will ensure the dam is a lifelong asset and will deliver for an even longer term than promised by the repair,” he said. “The Queensland Government will always listen to the experts and the expert advice tells us we cannot repair the existing dam wall.

“We are not going to lose a minute, with Sunwater appointing its construction partner and early works at the site continuing full steam ahead to ensure the new dam wall can proceed as quickly as possible, once all approvals have been obtained, ” Minister Butcher added.

A business case for the new dam wall has been initiated, with environmental approvals to be sought subsequently. CPB Contractors/Georgiou have been appointed as construction partners, and GHD will serve as the ongoing design partner.

Moreover, the Government has tasked Sunwater with a detailed business case to expand the irrigation network within the Bundaberg Water Supply Scheme, addressing capacity constraints. This initiative aligns with the draft Bundaberg Burnett Regional Water Assessment's key recommendations.

"The Miles Government is drawing a line in the sand. Making sure that we deliver on our commitment to restore the water supply in full, while eliminating any doubt for safety and water security of Bundaberg,” commented Member for Bundaberg, Tom Smith. “My commitment has always been to restore the water supply and to keep people safe. Today, I join Minister Butcher in keeping that commitment to the whole of the region. The evidence is clear, but so is the way forward. A new wall across the Burnett River will deliver a new strength for the agricultural and horticultural productivity of this region."

Since December 2021, Sunwater has been advancing the second stage of the Paradise Dam Improvement Project Detailed Business Case, prompted by the Queensland Government's commitment to restoring the dam to its full height and original capacity.

As an integral part of this comprehensive business case, an intensive testing program has been implemented to guide the development of the design. This rigorous testing has brought to light three unforeseen issues related to the long-term strength and quality of the dam's concrete: swelling clay, cement leaching, and carbonation. 

The emergence of these issues is unprecedented. Typically, dams are not subjected to long-term strength loss testing, and given that Paradise Dam was only constructed 18 years ago by the Burnett Water Alliance, such significant issues were unexpected.

Consequently, Sunwater, in collaboration with its partners and independent experts, were required to develop a bespoke and world-first testing program. The results from this program reveal that Paradise Dam was constructed with a notably higher percentage of clay compared to the majority of other roller compacted concrete dams worldwide.