Spillway and Embankment

Grahamstown Dam is the major water storage reservoir of the Hunter Water Corporation, supplying the Newcastle and Lake Macquarie regions. To increase storage, improve water level control systems and boost flood discharge capacity, Abergeldie were contracted to construct a new control structure, a zig zag concrete spillway and major new earth embankment.

Complex Challenges:

An adjustable steel formwork system was developed for the construction of the labyrinth spillway to achieve a tolerance on the weir crest of -0+2mm.

An original requirement for the staging of works was the completion of the control structure and a portion of the spillway wall to enable control of the water level in the lake. Abergeldie proposed and implemented an adjustment to the order of works by constructing diversion works prior to completion of the control structure. This allowed works to the main embankment to commence earlier and accelerated the construction process.

Business unit:



Hunter Water Association

Current status:


Start date:

February 2004

Completion period:

September 2005

Contract type:

Lump sum


$14 million