Tillegra Dam, Australia

Hunter Water, a specialist water and wastewater company, commissioned Aurecon to undertake an environmental assessment of the proposed 450 billion litre dam on the Williams River in the Hunter Valley.  

Tillegra Dam was proposed to provide water security for the half a million residents of the Lower Hunter Valley and provide at least 50 years of growth potential for the region. Aurecon’s challenge was to provide a robust environmental assessment and determine management and mitigation measures that could achieve acceptable environmental and social outcomes, and satisfy sustainable development principles.  

The project involved close consultation with both the client and stakeholders. It included an extensive assessment of aquatic and terrestrial ecology, hydrology, geomorphology, and estuary and wetland impacts to determine the environmental flow requirements and any impact on the Williams River and the Hunter Estuary. Socioeconomics, noise, air quality, traffic, and contemporary and aboriginal heritage were also assessed to develop a detailed understanding of any impacts or opportunities associated with the Tillegra Dam. Key issues could then be identified and addressed using Aurecon’s risk management processes.  

The group developed a comprehensive environmental assessment and prepared a detailed response to more than 2500 public submissions received during the consultation process. Some of the major achievements of the project included: 

  • The development of a sustainable bulk water transfer strategy
  • The development of a project specific sustainability framework, with the aim of making the dam carbon neutral – a first for Australia
  • A cemetery relocation plan
  • An integrated land use plan to manage activities in and around the reservoir and provide a range of recreational and visitor facilities
  • A fund to provide riverine, wetland and floodplain habitat rehabilitation and management
  • A plan to plant up to 1.5 million trees
  • A biodiversity corridor and carbon offset area
  • Providing funding for various local government projects
  • An environmental flow strategy to minimise impacts on the downstream river ecosystem
  • A plan to record or relocate heritage artefacts.


Roland Bow, Environmental Planner, Hunter Water, comments on Aurecon’s expertise and approach, saying that these “..have resulted in an outstanding result for the project. In the first instance, infrastructure has been located sympathetically within the landscape to avoid key features with high environmental value. Where impacts could not be avoided, they were subsequently otherwise managed or offset in a satisfactory manner that met the expectations of both Hunter Water and its stakeholders.”

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