With long-term predictions of above average rainfall, the client, Hydro Tasmania, wanted to raise the crest wall of the dam so it was better able to withstand large rainfall events.
Hydro Tasmania (a state-owned renewable energy generator), needed a major upgrade of the Murchison dam to make it safer for downstream communities in the event of the lake level rising and spilling over the dam wall.
Completed in 1982, the dam is situated on the Murchison River, about 50km north of Queenstown
Teams from VEC Civil Engineering worked in challenging conditions on Tasmania’s West Coast to complete the upgrades.
Work included raising the existing parapet wall by three metres to raise the design flood level, raising the nearby access road to match the new dam crest level. raising the spillway training wall height and altering its geometry, and the installation of downstream erosion protection.
Rugged conditions, no mobile phone coverage, some re-design, narrow work spaces at height, and an operational dam were just some of the challenges faced by VEC during the upgrade.
One thousand cubic metres of concrete, 270 tonnes of steel reinforcement and around 15 thousand hours on site were needed to complete the project.
The result, a safer dam site for Tasmanian communities.