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Monitoring flows in the Namoi, Macquarie and Warrego Rivers

In late March 2019, rain fell in the Namoi, Macquarie and Warrego catchments which led to the first significant flow to occur along those systems, for an extended period of time.

Such 'first flush' or resumption of flows, carry with them a significant ecological, socio-economic and cultural value, providing the local ecosystem and community much needed relief during long times of dry. In recognition of this the New South Wales Government implemented a temporary limit on extraction to coincide with the flow to help maximise its ability to provide local benefit.

The Murray–Darling Basin Authority (MDBA) monitored the flows using free, open and public satellite imagery from the European Space Agency Sentinel-2 satellite system, to better understand the hydrologic behaviour of these areas during a dry period as well as monitor the progress of the flow for compliance purposes.

This report presents the monitoring results and highlights landscape changes seen, where significant extraction and capture was seen to occur as the flow arrived. This work highlights the importance of adequate protection of critical flows and the limitations of imposing a temporary extraction limit while the flow event is en-route. It also highlights progress made over the last 12 months for the routine and efficient use of satellite imagery as one line of evidence for compliance purposes.

Publication error: On 17 October 2019, the MDBA inadvertently published a draft version of the report Monitoring first flush flows in the Namoi, Macquarie and Warrego River. The MDBA replaced this version with a final report at 8:30pm 18 October 2019. The MDBA acknowledges publication of an earlier version may have caused unnecessary concern and confusion to landholders. Satellite images alone are not evidence of illegal activity, they indicate areas for further consideration and possible compliance investigation. The MDBA has uploaded an updated version of the report, and will now review its publishing practices.

Murray–Darling Basin Authority's response to the Interim Inspector General's investigation into the release of the 'First Flush Flows report'

On 21 October 2019, the Hon David Littleproud MP, requested the Interim Inspector–General, Murray–Darling Basin Water Resources investigate the release of the Murray-Darling Basin Authority's (MDBA) draft report titled, 'Monitoring first flush flows in the Namoi, Macquarie and Warrego Rivers – Remote sensing for compliance and ecohydrology'.

The investigation considered the events that led to the premature release of the draft report, the MDBA’s response to this, and the overall adequacy of MDBA’s procedures for managing the release of compliance and enforcement related information.

The Interim Inspector General released his report (see link below). The MDBA accepted all of the Interim Inspector General’s recommendations, and in response:

  • adopted new procedures for identifying, managing and releasing compliance information
  • improved the governance arrangements around sharing compliance information with Basin States
  • strengthened internal controls around the MDBA's publication process, to mitigate the risk of premature or inadvertant releases.

Related links


Monitoring 'first flush' flows in the Namoi, Macquarie and Warrego Rivers

This report replaces an earlier version and was published at 8:30pm on 18 October 2019.