Document Scientific review: Lower Lachlan Groundwater Sharing Plan (pdf 7.3 MB)

Review completed

The NRC reviewed the Lower Lachlan Groundwater Sharing Plan and provided advice to the Government in November 2006. The Government provided a Terms of Reference for this review.

NRC's advice to Government

The report, Scientific review: Lower Lachlan Groundwater Sharing Plan, includes:

Terms of Reference
Findings and recommendations

Terms of Reference

Through its Terms of Reference, the Premier of NSW requested the NRC to review the scientific basis of aspects of the Water Sharing Plan for the Lower Lachlan Groundwater Source, prior to the plan’s commencement. The Premier sought advice on the:

scientific basis for the estimated average annual recharge
Lachlan surface water flow requirements to provide for the average annual recharge
scientific basis for exclusion of recharge estimates west of the Cobb Highway
scientific basis for the provision of water for groundwater dependent ecosystems (GDEs).

The report outlines the NRC’s findings and recommendations on each of the above aspect.

Findings and recommendations

The NRC commissioned URS Australia Pty Ltd (URS) to undertake a scientific review including coordinating input from a number of experts. The NRC has drawn on the URS report to develop its findings and recommendations.

Overall, the NRC has found that the information used to inform the average annual recharge estimate and the provision for GDEs contains relatively high levels of uncertainty. Improving the knowledge base is critical to improving the quality of the plan and to providing greater certainty for groundwater users.

The report provides findings in respect of each of the Terms of Reference.

The NRC has developed a series of recommendations in response to these findings. Some of the recommendations focus on making provisions in the plan for the uncertainty in the available information as well as improving the information base that informs the plan. This should allow scheduled reviews of the plan to be brought forward as this information becomes available. Significant advances in the quality of the plan are unlikely without this additional work.

Review process

The major components of the review process are described below.

Review component	Process
Commission independent Scientific Expert Review	The NRC appointed URS to lead an independent scientific review of components of the plan.
Consultation with stakeholders	URS consulted stakeholders to understand their key concerns and to help identify available information.
Expert workshop	URS facilitated a workshop of experts to examine the conceptual model of the groundwater system and its interaction with surface water. Experts included three specifically engaged for the review, DNR staff and experts engaged by groundwater users.
Review of GDEs	Existing information and evidence of GDEs was evaluated.
Preparation of review report	URS drafted, and finalised its report Scientific Expert Review for the Lower Lachlan Groundwater Sharing Plan. The draft report was peer reviewed by participants at the workshop.
NRC findings and recommendations	The NRC prepared its findings and recommendations after considering the evidence documented in the Scientific Expert Review and submitted its report to the Premier in November 2006.
Advice considered by Government	The Government considered the NRC's advice and amended the Lower Lachlan Groundwater Sharing Plan.