The refurbishment work recently completed on Hydro Tasmania’s Rowallan Dam won the utility a Tasmanian Project of the Year award from the Australian Institute of Project Management.
The award, given in the construction/engineering category, recognized excellence in project management for the refurbishment.
Rowallan Dam is a 43-meter-high earth and rockfill dam on the Mersey River in northern Tasmania. The dam was built from 1964 to 1967 and comprises two embankments separated by a central concrete-lined spillway.
Rowallan Dam impounds water for a 10.5-MW hydroelectric generating station containing a single Francis turbine. The unit began operating in 1968.
In 2011, Rowallan Dam was assessed as part of a regular and planned risk assessment for all of the utility’s infrastructure. The dam’s performance was consistent with expectations for a dam of its design, construction and age. However, improved understanding of the dam’s risks meant Hydro Tasmania was able to reduce risks that were unforeseen in 1968. The primary outcome was that the risks were higher than previously thought, particularly in relation to the spillway’s tall and slender concrete walls.
The two-stage refurbishment involved strengthening the spillway walls and improving the capacity of the dam to withstand large floods. Work was conducted over the summers of 2013 to 2014 and 2014 to 2015.
The project cost A$13.4 million (US$9.9 million) and also included improving the core and filters within the embankment. The work was performed as part of Hydro Tasmania’s rolling 10-year asset management plan.