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Lachlan water security investigation

Lachlan water security investigation

Belubula river

Water security has historically been a challenge in the Lachlan Valley and is limiting economic growth for the region.
The valley has been subject to severe town water restrictions with long periods of little or no general security, agricultural water availability and restricted high security water.

About the project

WaterNSW is responsible for delivering and operating infrastructure to provide for the State’s bulk water supply needs. As part of a broader commitment to improve the Water Security for Regions, the NSW Government has committed to investing in the water supply for the Lachlan region.

Phase 1 Preliminary Water Storage Investigation - Complete

Phase 1 of the Lachlan Valley Water Security project was undertaken by WaterNSW in 2014. This first phase identified a range of different options for improving regional water security including the construction of a new dam at various sites and the upgrade of existing dams.

Key recommendations from this phase included:

  • progress with field investigations for a new dam in the area near Cranky Rock. Investigations should focus on potential foundation and storage integrity risks.
  • undertake a cost-benefit analysis to determine the economic value of the investments in water security improvement in the region.

Phase 2 Investigations – Ongoing

In late 2016, WaterNSW announced that it had engaged GHD as its strategic partner to assist in delivering Phase 2 of the Lachlan Valley Water Security Project.

Phase 2 of the project includes the following activities:

  • Consulting with stakeholders and the community.
  • Establishing the need, service levels, and reviewing  various build and non-build options including those from Phase 1, to develop a shortlist of options for further assessment.
  • Carrying out field investigations at sites near Cranky Rock to assess major risks.
  • Preparing a preliminary business case including a detailed cost-benefit analysis.

If approved to proceed, a final business case with then be prepared to seek funding for the preferred option.

Phase 2 will involve an assessment of a range of issues including social, economic and environmental factors, in order to determine the preferred option for inclusion in the final business case. Consultation with the community and key stakeholders will be a key focus to help WaterNSW assess the feasibility  of  options.

Phase 2 - Part 1: Project Timeline for the Preliminary Business Case

December 2016 - February 2017
  • Commence stakeholder consultation process - including the establishment of a Community Reference Group (CRG), regular project bulletins and updates on the WaterNSW website
  • Review options and develop a long list for consideration
  • Carry out preliminary site surveys and non-invasive investigations
  • Begin development of preliminary business case
March 2017 - June 2017
  • Carry out geotechnical and environmental site investigations
  • Develop feasibility designs for build options
  • Develop non build options such as operation and rule changes
  • Continue stakeholder consultation process
  • Willingness to Pay and Cost Benefit Analysis undertaken
  • Select preferred option and begin concept design for inclusion in the preliminary business case
July 2017
  • Develop a shortlist of options
August 2017
  • Submit preliminary business case
October 2017 - February 2018
  • Review and further refinement of preferred option(s)
  • Continue stakeholder consultation process
  • Develop final business case
Mid 2018
  • Submit final business case

Current Activities

Technical studies

The project team have been reviewing the technical studies undertaken by WaterNSW during Phase 1, which had looked at options for a new dam in the Upper Valleys.

Following this review, the focus by the project team has been on considering the various size dams at two Cranky Rock sites on the Belubula River, upstream of Canowindra.

A substantial part of their work has been on understanding the potential environmental impact on the Cliefden Caves, which are located upstream of the proposed dam sites.

Field studies

The project requires site investigations in order to better understand the geology and environment of the Cranky Rock area to assess its suitability for a dam as well as to better understand potential impacts.

Over the past few months the project team have been liaising closely with landholders to carry out field investigations including a geophysical trial in the Cranky Rock area. This work included ground based investigations as well as the use of aerial drones to view and record ground conditions. This  work is establishing a better understanding of the relationship between the storage of water at Cranky Rock and potential flooding of the Cliefden Caves.

WaterNSW is currently analysing the geotechnical information from the field studies in the Cranky Rock area to confirm suitability for a dam. The project team is also developing the long list of project options with recent inputs from valley stakeholders (the Community Reference Group) and government.  The options will be investigated and evaluated to produce a short list, which will be the subject of more detailed study.

Cost Benefit Analysis study

As part of these Phase Two Investigations, a Cost Benefit Analysis (CBA) study is being undertaken. The CBA will be an important part of the preliminary business case. It will compare the forecast costs with the forecast benefits for various options and determine which option offers superior value for  money.  The CBA will help to make sure that the preferred option provides the greatest community benefit for the cost.

Next steps

Over the coming months we will complete our technical investigations and cost benefit analysis and then seek feedback on a short list of options. Feedback from the community and stakeholders will help inform WaterNSW’s thinking on the preferred options for inclusion in the preliminary business  case.

Project Documents



The phase 1 scoping study investigations were completed in December 2014 recommending further studies in the vicinity of the Cranky Rock area on the Belubula River. The following report and executive summary provides further detail:

Fact sheets

Media releases

How to get involved

Opportunities for being kept up to date and for providing input to the development of the preliminary business case will occur throughout 2017. Below are some of the ways you can be involved or kept up to date.

Project Updates

We will provide regular updates over the course of the project via email and on the WaterNSW website. Please contact us to join the project mailing list.

Email us at:

Community Information Sessions

Out project team will be holding community information sessions where you will have the opportunity to provide feedback and ask questions about the project. These sessions will be advertised in local newspapers and here on our website.

Community Reference Group

We have formed a Community Reference Group (CRG) for the project. The CRG membership was decided following a thorough nomination and selection process that was completed in February. The first CRG meeting was held on Thursday 16 March in Orange and the group will meet again in July.

The CRG is a key form of communication between the local community, stakeholder groups and the project team. Members of the group are:

* Centroc - Bill West, representing Upper Lachlan councils and water utilities for townships.

* RamRoc - Peter Laird, representing Lower Lachlan Shire councils.

* Central Tablelands Water - Cr David Somervaille.

* Save Cliefden Caves Association -Armstrong Osbourne.

* Orange Speleological Society - Denis Marsh.

* Belubula Landholders Association - Michael Payten

* Lachlan Valley Water - Tom Green.

* Environmental Water Advisory Group (Lachlan Riverine Working Group) - Fin Martin.

* Lachlan Customer Service Committee - Mary Ewing.

* Wallamundry Narrothong Creek Water users -Wally Dawson.

* Booboroi Creek Water users - Mark Kearine.

* Wiradjuri Local Aboriginal Land Council (Cowra) -Les Coe.

* Libby Skipworth - Lake Cargelligo representative.

* Cyril Smith (independent community rep).

* Mark Brown (independent community rep).

Contact us

To learn more about the project, contact our Community Engagement Team:

Phone: (02) 9865 2330


Monday 22 October
1,622,015 ML
2,581,850 ML
9,938 ML
1,420 ML
-656 ML
Monday 22 October