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Porters Creek Dam Safety Upgrade
Upgrade to a 1960s dam to address concerns about its structural integrity

Background

Porters Creek Dam is located 60 km south of Nowra in southern NSW. It was originally constructed in 1967 with a post-tensioned concrete spillway and reinforced concrete stilling basin. There was concern about the structural integrity of the anchors, which could corrode and lead to failure.

The dam is 17 m high and 240 m long with earthen left and right abutments and a reservoir volume of approximately 1,900 ML.

Scope

The project included:

  • Excavation of foundation for a new mass concrete buttress, stilling basin and spillway
  • Construction of a 5,000 m3 mass concrete buttress
  • Construction of a 300 m3 reinforced concrete stilling basin, return channel, energy dissipation blocks and training walls
  • 5,000 m3 gravel filter blanket drainage at left and right abutments
  • Remove and replace two DN600 gate valves and the outlet trash screen within the dam
  • N32 and N24 rock anchors
  • Dam safety instrumentation including precision monitoring survey network, seepage and survey monitoring
  • Construction of a 14 km access track, gates and fencing

Outcomes

Concrete mix design, temperature monitoring and sequencing of over 150 concrete pours was required for the mass concrete buttress.

The project was delivered on time and on budget with zero Lost Time Injuries.

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