A NSW Government website

Licensing floodplain harvesting

Independent peer reviews on floodplain harvesting

We aim to ensure that the best currently available technology, data, and modelling is used in implementing the NSW Floodplain Harvesting Policy and is peer reviewed.

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Building public confidence with independent reviews

The department is working to build and improve public confidence and trust in the NSW Floodplain Harvesting Policy, and how its implementation provides the best outcome for all water users and the environment. This includes significant investments in technology to build accuracy and confidence in floodplain harvesting volumetric entitlement estimates. We aim to ensure that the best currently available technology, data, and modelling is used and is peer reviewed.

Independent peer reviews of the policy and independent modelling reports

Implementation dates for the NSW Floodplain Harvesting Policy have changed due to the disallowance of amendments to the Water Management (General) Regulation 2018 in 2020 and 2021, which defined the process for issuing floodplain harvesting licences and the measurement requirements on those licences. This means the dates specified in our reports and guidelines may be superseded.

The department is committed to this important reform to ensure that limits on take apply to floodplain harvesting, and that this take is accurately measured. Licensing will bring floodplain harvesting into line with other forms of take, enabling monitoring and management and providing certainty in the provision of water required for the environment and other water users.

A peer review is a common method to evaluate scientific outcomes. It’s a process where scientists and experts (peers) evaluate the quality of other experts’ work. Peer reviews provide an independent assessment of the work to ensure it is rigorous and coherent. It uses past research and experience to achieve the best outcomes for all stakeholders.

Independent peer review of the policy

Independent peer review of the NSW Floodplain Harvesting Policy

The department, together with the Murray-Darling Basin Authority, commissioned an independent peer review of the implementation of the NSW Floodplain Harvesting Policy (the policy) in northern NSW.

The key aim of the review was to provide transparency and give confidence to stakeholders that the technical information and processes used would support policy implementation.

The independent reviewers were engaged in 2018 to assess the policy and the modelling undertaken. The Floodplain Harvesting Independent Review (PDF, 1419.81 KB) provided recommendations for improvement, including 16 key recommendations and 48 other recommendations that follow five key themes.

Key recommendations

The department accepted these recommendations in full and responded to them in the Floodplain Harvesting Action Plan (PDF, 421.67 KB). The action plan details how we will implement the recommendations of the independent review and reinforces key priorities in the delivery and implementation of the NSW Floodplain Harvesting Policy.

Read the:

Independent peer review of modelling reports

Modelling of extraction limits and current diversions

Following their review of the implementation of the NSW Floodplain Harvesting Policy, the reviewers have continued to work with the department to review key modelling reports and other activities against their review recommendations.

Read the valley modelling peer review reports:

Landholder farm-scale validation - the modelling submission process

Additional reviews were conducted to assess landholder submissions received as part of the farm-scale validation process, which itself was instigated as an outcome of the independent review into floodplain harvesting policy implementation.

Read the valley modelling peer review reports:

Independent peer review of satellite derived irrigated cropping areas

Review of satellite derived irrigated cropping areas for the unregulated properties in the Namoi Valley

Historically irrigated areas are important for determining floodplain harvesting licences in unregulated river water sources. Remote sensing is the primary line of evidence used to identify these historical areas.

To improve trust and confidence, the department engaged Alluvium to independently assess the remote sensing methodology used and to suggest any improvements that could be made.

The Alluvium report (PDF, 8234.62 KB) finds that remote sensing is a well-recognised and appropriate method for determining irrigation areas. However, advanced analyst skills are required to reliably interpret the results.

A possible improvement suggested by Alluvium was to adopt a more automated workflow process to reduce reliance on analyst skills and in turn improve consistency and efficiency.

The automated workflow gave very similar overall results to the department, providing confidence in the overall outcomes. However, in 8% of cases the results indicated significantly different outcomes at the property scale.

The department has now reviewed these cases and has found that the automated approach is generally over-estimating irrigation areas due to generalities in the approach. The use of advanced analyst skills to include a quality assurance step increases the level of confidence in the accuracy of the department’s method.

Based on this report, the department’s remote sensing approach is considered fit for purpose and reasonable for use in determining replacement floodplain harvesting access licences in the Namoi unregulated river system.

Read the report: Review of satellite derived irrigated cropping areas for the unregulated properties in the Namoi Valley (PDF, 8234.62 KB).

Independent peer reviewers

The department engaged reviewers who are recognised nationally and internationally as experts in their respective fields. They were not involved in any activities regarding the modelling and/or implementation of the NSW Floodplain Harvesting Policy prior to their commencement of the review tasks. Therefore, it was a truly independent review, without any preconceptions of departmental influences on the approach or considerations.

Appointment criteria

The reviewers were appointed based on the following reasons:

  • demonstrated capabilities to provide quality, responsive and specialist advice
  • specialist experience in water modelling and floodplain harvesting
  • technical capabilities for the work
  • corporate knowledge and continuation of the work program
  • immediate availability to service the needs of the program
  • limited supply in the market for specialists (consultants that are independent from the department) with the required knowledge to provide expertise in water modelling and floodplain harvesting
  • vetting by the department as part of the contracts and pre-qualification scheme (maximising savings through negotiated price reductions, enhancing the available product range and increasing supplier contract performance).

In undertaking their review, the reviewers also consulted widely with peers in the Murray–Darling Basin Authority and other Commonwealth agencies, in addition to stakeholders from a wide range of interests, such as landholders and water users, plus environmental and natural resource group members. The department is confident that their review represents an independent assessment of the issues associated with the implementation of the NSW Floodplain Harvesting Policy.


Tony Weber

Tony Weber is a leading practitioner in the catchment modelling and water quality field in Australia. Prior to joining Alluvium, he worked at BMT WBM for 13 years where he led the water quality discipline across their Australian operations. Tony has over 27 years of experience in the water industry, delivering a range of catchment modelling, water-sensitive urban design, integrated water management, water quality and stormwater management projects.

Greg Claydon

Greg Claydon has extensive water industry and natural resources management knowledge, experience, and achievements, built on his roles as a senior executive with Queensland and Western Australia state government water, environment, and natural resources agencies. He is recognised at state, national, and international levels for his work in water and natural resources reforms.

Contact us

If you require assistance in reading these documents, please contact 1300 081 047 or  water.enquiries@dpie.nsw.gov.au