Tyabb Reservoir - Earthworks, Lining and Floating Cover

John Holland - KBR Joint Venture

Ertech was contracted to design and construct the earthworks, lining and floating cover for the Tyabb Reservoir.

EWebsiteTyabb Reservoir Exp

Fast Facts

Location: Tyabb, VIC

Contract Value: $12M

Start: March 2016

Completion: February 2017


Tyabb Reservoir is managed by Melbourne Water to supply water to the Mornington Peninsula. The purpose of the cover and lining is to protect the quality of the drinking water, which comes from Melbourne Water’s Cardinia Reservoir or Tarago Treatment Plant via large water mains. The purpose of the project is to upgrade the existing facility and divide the reservoir into two relatively equal sized basis. New pipework and valves are also to be installed to provide additional control of the new facility.

Ertech’s design and construction contract, which formed part of Melbourne Water’s Capital Works Program, included:

  • Demolition of existing structures and removal of lining system
  • Supply and install fill material to divide the existing reservoir into two basins of 140Ml and 180Ml respectively
  • Installation of mild steel cement lined (MSCL) and 316 Stainless Steel Schedule 10 pipework and associated fittings
  • Construction of new insitu (up to 8m high) and precast concrete structures of both a water retaining and excluding nature
  • Supply and install a multi-layer lining system and floating cover to both basins with a surface area of 28,600m2 and 32,800m2 respectively.


  • The initial scope involved demolition of the inlet structure. In partnership with the client, we redesigned the pipework which meant there was only a need to remove the lid from the concrete structure, rather than demolish the entire thing. The old structure was eventually incorporated into the works.
  • The internal water storage embankment was built using graded rock to mitigate the risk of wet weather delays during the winter construction period, enabling the achievement of the target program.
  • The liner was sealed against new structures using a sandwich system, incorporating hydrophilic paste.