Floodplain harvesting licence rules in the water sharing plans for Gwydir valley

The draft rules for floodplain harvesting licences to be included in water sharing plans within the Gwydir valley was released for comment through public exhibition commencing on 12 February 2021. Public exhibition ran from 12 February 2021 until 12 March 2021.

Download high resolution diagram–Gwydir timeline

Past consultation sessions

The department held a public webinar, face-to-face public meetings in the Gwydir valley area, and a series of targeted consultation events with specific stakeholder groups. All stakeholders were provided with information about the implementation of the NSW Floodplain Harvesting Policy and proposed water sharing rules for floodplain harvesting licenses in the Gwydir valley.

Technical reports

The below technical reports were developed by the department to help inform the development of the draft floodplain harvesting licensing rules in the Gwydir valley. To help you make an informed submission please ensure you have read the report to assist community consultation and viewed the other relevant technical reports.

If you require assistance in reading these documents, please contact +61 2 9338 6600 or water.relations@dpie.nsw.gov.au.

Report to assist community consultation

The Gwydir: Floodplain harvesting in water sharing plans–Report to assist community consultation report aims to assist the community in understanding the proposed types of rules for floodplain harvesting access licences in the Gwydir valley. It also provides a summary of the other four technical reports and explains the interaction between the rules, modelling and the expected environmental benefits once they are put in place.

Modelling reports

The NSW Floodplain Harvesting Policy requires that individual entitlements in regulated river systems will be informed by a capability assessment that considers the works used for floodplain harvesting and the opportunity to access floodplain flows based on location and climatic variability. This capability assessment is undertaken through river system models.

Building the river system model for the Gwydir Valley regulated river system describes the development of the Gwydir valley river system model. The model was developed using multiple lines of evidence and best available industry data. The report provides evidence and assessments to demonstrate that the model is fit for purpose.

Floodplain Harvesting Entitlements for Gwydir Regulated River System: Model Scenarios Report, describes how the model of the Gwydir valley was used to estimate the baseline diversion limit, and to subsequently estimate individual floodplain harvesting entitlements.

The modelling reports for the Gwydir valley have been independently peer-reviewed - Gwydir reports review–summary, January 2021.

Environmental outcomes reports

Harvesting of water from floodplains reduces the volume, frequency and duration of floods and can change the timing of flood events, impacting on the health of floodplains and downstream waterways. The NSW Floodplain Harvesting Policy will provide a more sustainable level of water diversions from the floodplain.

Hydrological metrics for native fish, floodplain native vegetation, waterbirds, key ecosystem functions and wetlands were modelled for two scenarios. Implementation of the policy is predicted to improve the number of flow days, frequency and timing of floods for native fish, waterbirds and floodplain vegetation.

Environmental outcomes of implementing the Floodplain Harvesting Policy: Gwydir report provides a detailed assessment of the likely benefits for the environment of implementing the policy in the Gwydir valley.

A summary of the environmental outcomes predicted for the Border Rivers, Gwydir and Macquarie Valleys is available below.

Downstream effects reports

The NSW Floodplain Harvesting Policy will restrict the volume of water that can be taken from the floodplain providing gains to the system through foregone diversion.

Any gains in upstream systems such as the Gwydir valley will translate into the downstream with additional volumes originating in each of the Barwon-Darling tributary valleys contributing to connectivity between the broader northern Basin system and provision of increased flows towards Menindee Lakes and into the River Murray.

Modelled downstream effects of licensing floodplain harvesting in the Gwydir valley report quantifies the potential downstream impacts of these increased flows. This report includes work completed for the NSW Border Rivers and the Gwydir valleys.

Rainfall Runoff Exemption Supplementary report

The proposed rainfall run-off exemption has the potential to impact floodplain harvesting modelling in the NSW Gwydir valley. The department has proposed a regulation to exempt rainfall run-off that is collected in a tailwater return drain from requiring a water access licence and a water supply works approval. The successful commencement of this exemption will impact floodplain harvesting modelling in the NSW Gwydir valley. This report clarifies the scale of this potential impact on licence shares, the environment, and downstream outcomes.


Summary of draft rules for floodplain harvesting in the Gwydir valley

Summaries of the proposed rules for floodplain harvesting (regulated river) access licences and floodplain harvesting (unregulated river) access licences in the Gwydir valley floodplain are provided below. Feedback on the draft rules was sought through a public submission process that ran from 12 February 2021 until 12 March 2021.

Floodplain harvesting (regulated river) access licences – rule summary

Type of ruleProposed rule for floodplain harvesting

Account management

Take limit: 5 ML per unit share over three consecutive years

Carryover: Unlimited, subject to the account limit

Available water determination

Initial available water determination of 5 ML per unit share, or

Initial available water determination of 1 ML per unit share, or a lesser amount to ensure compliance with the extraction limit

Available water determination of 1 ML per unit share every year after that, subject to increases or decreases to respond to growth or improved accuracy in calculating the extraction limit

Permanent trade

Establishing trading zones that largely reflect unregulated river water sources to protect important wetlands

No permanent trade of floodplain harvesting (regulated river) access licences between trading zones

No nomination of works located outside the Gwydir valley floodplain

Granting or amending water supply works approvals

No modification of works located in management zones A or D established under the Floodplain Management Plan for the Gwydir Valley Floodplain 2016

No new works constructed in management zones A or D

No new or modified works outside management zones A or D if the construction or modification would result in an increased rate of take for works located in management zone A or D

Access rules

Water must not be taken from works that are located in the following management zones and are nominated by a floodplain harvesting (regulated river) access licence when active management is being applied:

  • Upper Gingham Watercourse Management Zone
  • Lower Gingham Watercourse Management Zone
  • Mallowa Creek Management Zone

Note: This proposed rule is based on the creation of overbank flow in the above management zones during periods of active management.

Floodplain harvesting (unregulated river) access licences – rule summary

The process for determining entitlements of floodplain harvesting (unregulated river) access licences and unregulated river access licences is the same. Accordingly, it is proposed to apply the same rules to floodplain harvesting (unregulated river) access licences as currently exist for unregulated river access licences in the relevant water source and/or management zone, where appropriate.

Type of ruleProposed rule for floodplain harvesting

Account management

Take limit: 3 ML per unit share over three consecutive years

Account limit: 3 ML per unit share at any time

Available water determination

Initial available water determination of 1 ML per unit share

Available water determination of 1 ML per unit share every year after that, subject to decreases to respond to growth

Permanent trade

Permanent trade of floodplain harvesting (unregulated river) access licences will reflect the existing permanent trade rules that are applied to unregulated river access licences in the Gwydir Unregulated River Water Sources.

No nomination of works located outside the Gwydir valley floodplain

No nomination of new works located in management zones A or D

Granting or amending water supply works approvals

No modification of works located in management zones A or D established under the Floodplain Management Plan for the Gwydir Valley Floodplain 2016.

No new works constructed in management zones A or D

No new or modified works outside management zones A or D if the construction or modification would result in an increased rate of take for works located in management zone A or D

Access rules

Water must not be taken from works that are located in the following management zones and are nominated by a floodplain harvesting (regulated river) access licence when active management is being applied:

  • Upper Gingham Watercourse Management Zone
  • Lower Gingham Watercourse Management Zone
  • Mallowa Creek Management Zone

Note: This proposed rule is based on the creation of overbank flow in the above management zones during periods of active management.

What we heard

The what we heard report summarises the feedback the NSW Government received during the public consultation sessions and from written submissions for the Gwydir valley.

Download report

The Gwydir Submissions Report (PDF, 1851.97 KB) details the submissions received via the online platform. Please note only submissions where approval was given to publish have been included. Written submissions or attachments with additional information can be found below.