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| John Holland

Chaffey Dam Upgrade AN INNOVATIVE UPGRADEJohn Holland |

| John Holland

Chaffey Dam is situated on the Peel River, made of semi-precious stone, and its unusualin the New England region of NSW. Located morning glory spillway – one of only two in Aus-43 kilometres south-east of Tamworth, and 400 tralia, and so named because of the spillway’skilometres north of Sydney, its main purpose similar shape to the flower. The lake and itsis to supply irrigation and stock needs in the foreshores are also a popular destination forPeel River Valley, and supply water to the city water sports and fishing enthusiasts, natureof Tamworth. The dam currently holds a max- lovers, bushwalkers, campers and picnickers.imum of 62,830 megalitres of water – which The original of Chaffey Dam began in 1976adds up to about 30,000 Olympic swimming and was completed in 1979. In the years since,pools. the city of Tamworth and the Peel Valley has In addition to its main function, Chaffey grown and evolved, and dam safety standardsDam also provides valuable public recreation have evolved alongside them. To accommo-in an attractive setting. The site is unique in in- date that evolution, WaterNSW has committedland NSW for its distinctive brick-red rock wall to upgrading and augmenting Chaffey Dam,John Holland |

| John Holland

increasing the storage’s capacity from 62,830 The spillway was constructed by blasting andmegalitres to roughly 100,000. excavating rock adjacent to the left hand abut- For help accomplishing this goal, WaterN- ment of the dam wall.SW turned to John Holland, one of Australia’s In 2011, Stage 2 of the upgrade – whichmost longstanding specialists in engineering was valued at $50 million – commenced at theand contracting, and the builder of the original design stage. John Holland was later awardedChaffey Dam. the construction contract, and construction be- gan in 2014. A BETTER RESULT Tony O’Relly was the Project Manager on the contract. He has personally been involved Stage 1 of the Chaffey Dam upgrade was in civil construction since 1976 and has workedvalued at $13 million, and included construction on a long list of projects in the years since – in-of a 35-metre auxiliary spillway with a release cluding bridges, wharves, road construction, aplug. John Holland commenced construction flour mill, and a variety of major rail civil works.in early 2010 and completed it in early 2011.John Holland |

He joined John Holland when they acquired 1.8-metre parapet wall, as well as raising theTransfield Construction in 2003. morning glory spillway. The aim was to in- According to Tony, John Holland was able to crease the supply of reliable and affordablebring some fresh thinking to the Chaffey Dam water to the region and help drought-proof theupgrade, which enabled the client to achieve a city into the future.better result for less money. The $18 million dam safety upgrade com- “We were able to re-scope the work and ponent of the works was funded by the NSWcome up with some innovative ideas, such that Government. The $31.781 million augmen-capacity of the dam was able to be increased tation component of the works, meanwhile,at a lower cost, which then allowed WaterNSW was funded by the Australian Government’sto proceed with the project,” Tony explains. National Water Security Plan for Cities and Stage 2 of the Chaffey Dam upgrade and Towns ($18.145 million), the NSW Govern-augmentation involved raising the dam wall ment ($9.668 million) and Tamworth Regionalwith a reinforced earth embankment and Council ($3.968 million). | John Holland

WaterNSW – which manages Chaffey gaged with them. As such, they helped raiseDam, as well as 41 other large dams across money for two local public schools and the lo-NSW – were the clients on the project. Tony cal cricket club.describes John Holland’s relationship with “It’s important for them to see that John Hol-them as “healthy and open.” land has an interest in the local community,” “We deal with each other on a daily basis at Tony says.various levels of management,” he says. “For John Holland also participated in the quar-example, we work with them on safety, quality, terly meetings of the Community Constructionengineering, environmental management, and Liaison Group (CCLG), which consists of keyproject management.” local stakeholders and was formed to operate WaterNSW has also been working closely during construction to provide a mechanismwith the local community and stakeholders for for updates and issue resolution. John Hollandmore than 10 years on the project, and it was assisted them – and various other associationsimportant for John Holland to be just as en- and groups – by helping with site visits, and byJohn Holland |

working closely with WaterNSW in preparing able Maximum Flood (PMF). By protecting thecommunity updates and news releases. dam from overtopping, John Holland is also protecting the local community downstream ZERO HARM from inundation from a collapsed dam wall. Safety was also a priority for John Holland em- In addition to planning for the future water ployees and subcontractors, Tony adds – justneeds of Tamworth and Peel Valley, the Chaffey as it is on all their projects.Dam was also upgraded and augmented to “John Holland’s safety culture is Zero Harmcomply with the latest safety standards set out and this is achieved through the various toolsby the Australian National Committee on Large in our system,” he says. “Safety is our top pri-Dams (ANCOLD) and by NSW’s Dams Safety ority. We prepare ‘Activity Method Statements’Committee (DSC). for all major construction activities and com- Specifically, Stage 2 of the safety upgrade plete ‘Tasks Risk Assessments’ for every activ-of the dam is related to protecting the dam ity in consultation with the workforce.”crest from overtopping in the event of a Prob- | John Holland

John Holland |

| John Holland

John Holland |

For example, one of the project’s main lenges was the most satisfying part of the job.safety challenges involved safely excavating “What I am proud of is the way we havethe dam crest to extend the existing filter ma- tackled each of the challenges and come upterials. Construction of a 6.5 metre high by 7.5 with methodologies which addressed safety,metre wide reinforced earth wall on the dam access and productivity concerns,” he says.crest was also an issue. Then there was thematter of raising the existing morning gloryspillway by 6.5 metres, which involved startingthe work seven metres down inside the spill-way. Each of these tasks proved challenging,but those challenges were overcome throughdetailed engineering planning and close con-sultation with the workers. According to Tony, overcoming those chal- | John Holland

John Holland |