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 2019–20

In 2019-20, the management of water for the environment will focus on maintaining drought refuges and core aquatic ecosystem values in the Macquarie-Castlereagh catchment.

Rainfall in the catchment is well below levels documented during the worst drought on record. When combined with warmer-than-average temperatures, the condition of rivers and wetlands is set to decline further from current levels.

Ongoing dry conditions are likely to result in low or no access to carryover balances.  In this situation, water managers cannot continue the three-year watering strategy for the Macquarie Marshes, developed in early 2017. Instead, efforts will focus on maintaining drought refuge pools within streams in the lower parts of the Macquarie catchment.

If successful, these refuge pools will allow native fish species to survive under the extreme drought conditions. Refuge pools will also support small numbers of waterbirds and riparian vegetation in some areas.

Further details on watering priorities for 2019–20 can be found in the Annual Environmental Watering Priorities 2019–20 (PDF 1.2MB).

Highlights from 2018–19

2018-19 proved a challenging year for all water users with a 70 per cent account use limit applied in September.

Within the context of the three-year watering strategy, 126.5 gigalitres of water for the environment was delivered to the Macquarie Marshes to build their resilience. Approximately 15,000 hectares of the targeted 21,000 hectares was inundated, with account restrictions and climatic conditions contributing to this smaller area.The release, made over 140 days between July and December, provided the opportunity for seed setting in marsh vegetation.The common reedbeds, water couch meadows, mixed marsh and parts of the river red gum forests of the Macquarie Marshes are well placed to withstand six to 12 months without inflow.

In a catchment-first, water for the environment was delivered to two locations to support native fish refuges.  The first was the lower Nyngan Weir Pool under an agreement with Bogan Shire Council to support the threatened olive perchlet. (300 megalitres).  The second delivery of 800 megalitres delivered via the Tenandra Scheme (an off-river irrigation scheme) into the Ewenmar Creek at ‘Old Bundemar Station’.