Annual environmental water priorities in the Macquarie-Castlereagh catchment

Water management will focus on maintaining drought refuges and core aquatic ecosystem values in the Macquarie-Castlereagh catchment this year.

Priorities for 2020–21

The Bureau of Meteorology has forecast a shift toward wetter than average conditions and warmer than average temperatures through winter–spring 2020 in the Macquarie–Castlereagh catchment this year.

In 2020–21, water managers will work to, at a minimum, avoid loss of key aquatic and wetland values in the Macquarie–Castlereagh catchment. Should the weather predictions eventuate, we will respond with actions to promote drought recovery, particularly in the mid-Macquarie River downstream of Warren and the Macquarie Marshes.

Supporting core refuges will allow native fish species to survive and avoid critical loss or damage to the semi-permanent wetland vegetation communities. Refuge pools also support small numbers of waterbirds and riparian vegetation in some areas.

If it becomes available, additional actively-managed water for the environment will be managed in collaboration with the EWAG to support drought recovery within the system. This includes 4,000 to 9,000 hectares of reed beds, water couch meadows, mixed marsh areas and river red gum forests in the Macquarie Marshes that were dry for extended periods within the record drought from early 2017 to early 2020.

Further details on watering priorities for 2020–21 can be found in the Annual Environmental Watering Priorities 2020–21 (PDF 2.3MB).

Highlights from 2019–20

Rainfall and tributary flows from February 2020 gave the Macquarie system a reprieve from the record drought, with a modest volume flowing into the regulated storages. However, the one to two-year outlook remains uncertain.

The natural resilience of the Macquarie River (mid and lower) and Macquarie Marshes has been severely impacted by the low and nil flows over this drought period. This ongoing lack of flow combined with high erosion from bare earth in the catchment resulted in significant fish kills in the regulated Macquarie River and the drying of pools downstream of Warren where the river flows were cut for drought mitigation.

Despite DPIE EES planning for a watering event in 2019-20 to support critical environmental assets with carryover balance from the 2016 Burrendong dam spill, the quarantining of all carryover meant that the planned environmental flows were unable to be undertaken.  As such, no managed environmental flows occurred in 2019-2020.