The National Capital Authority has commissioned a room-sized model of Scrivener Dam worth almost half a million dollars to help plan for "intensive" renovations.
It received $10.6 million in the 2019 federal budget to renew the dam on the Molonglo River and remediate walls surrounding the lake.
As part of that, the authority has hired a contractor to design, build and test a 1:40 scale model of the dam.
The 20-metre long and 15-metre wide model will include a detailed model of the upstream and downstream river corridor and be based in Sydney.
"The construction and testing of the physical model will provide a better understanding of how the dam and its environs respond to a range of operational scenarios and will inform the future of capital investment and safe management of the dam," a spokeswoman said.
"The project is currently in design phase and will be ready for testing in early February 2020."
The model will cost around $492,000.
Scrivener Dam was completed in 1963 to fill the Molonglo River flood plain and create Lake Burley Griffin.
In 2011, $20 million worth of unscheduled works forced the authority to delay major capital works at Barton and Regatta Point. The repair bill was later revised down to $8 million.
Former National Capital Authority chief executive Gary Rake revealed in 2013 he suffered many sleepless nights worrying whether the Scrivener Dam gates would collapse, after a contractor uncovered corroded bolts.
The authority was forced to lower the water level of Lake Burley Griffin by 50 centimetres to undertake repairs.
However the authority said earlier in the year the concrete gravity dam and the walls surrounding the landmark water body were functioning safely.
"Budget funding will enable an accelerated program of works that will extend the lives of these assets and ensure they can be maintained efficiently in the future," a spokeswoman said at the time.
"As these assets are now over 50 years old, they inevitably require ongoing repairs and maintenance to extend their useful lives, avoid expensive replacement works and ensure they continue to function safely."