Temporary water restriction for Barwon-Darling water source
Temporary Water Restriction (Barwon-Darling Unregulated River Water Source) Order 2019 (section 324 order)
Number 35, Tuesday 16 April 2019
The Commonwealth Environmental Water Holder (CEWH) and the NSW Environmental Water Holder have decided to make a release of 7.4 GL of held environmental water from Glenlyon Dam and up to 26 GL of held environmental water from Copeton Dam into the Border Rivers and Gwydir regulated water source respectively. This includes replenishment flows in the Mehi River in the Gwydir commencing 15 April 2019.
This decision comes following advice regarding the ecological health requirements of the river systems across the Northern Basin, in particular the stressed state of native fish communities.
It is expected that the northern flow event will provide a low flow through the Northern Basin to Walgett and possibly Brewarrina, refreshing habitat and connecting residual pools.
Reasons for decision
Section 324 of the Water Management Act 2000 (the Act) allows the Minister or a delegate to direct, by order, that temporary water restrictions within a water source(s) have effect for a specified period, if these restrictions are determined to be in the public interest. Examples of the public interest referred to in section 324(1) include “to cope with a water shortage, threat to public health or safety or to manage water for environmental purposes”.
There is a public interest in making an order to restrict take in the Barwon-Darling unregulated river water source as follows:
- “Manage water for environmental purposes” – there have been devastating fish kills in the Barwon-Darling. The protection affected by the proposed s.324 order targets replenishing refugia and pools in the Barwon-Darling River. The Commonwealth Environmental Water Holder has signalled her intent to deliver a northern refuge refresh event via the release of held environmental water from various storages scheduled to provide a combined flow to Collarenabri, connecting the Barwon-Darling to Walgett and possibly Brewarrina. Combined, these flows can break a cease-to-flow event of over 100 days in duration in the Barwon River and improve drought refuge habitat, including water quality. Critical cease-to-flow periods in the Barwon-Darling are generally thought to be in the range of 50 to 100 days. Specifically, the environmental objectives for the northern refuge refresh event are:
- to support flow dependent ecological assets and functions by providing replenishment of drought refuge habitat and connectivity of flow, and to protect native fish, including species listed under NSW and Commonwealth legislation, and the International Union for the Conservation of Nature list of threatened species;
- to stimulate some productivity of riverine ecosystems, and to provide improved dispersal opportunities and food sources to support native fish (Barwon-Darling River and northern tributaries at least downstream to Walgett and possibly Brewarrina); and
- to improve drought refuge habitat water quality.
- “to cope with a water shortage” - remaining water supplies in the Barwon-Darling River are at critically low levels (drought criticality stage 4 under the NSW extreme events policy) and must be protected for critical human needs. The restriction halts the extraction of water in the Barwon-Darling for general security irrigation. More water is protected in the river, improving the extent of the flows available for critical needs. Water is currently being carted to homesteads to meet critical needs.
- “threat to public health and safety” – town water supply and domestic supplies are crucial for public health and safety and are under threat without intervention. The township of Walgett has exhausted their weir supply. The restriction will maximise the volume of water in the system to recover the town supply by filling the weirpools for Collarenebri, Walgett, and hopefully Brewarrina.
Accordingly, the s.324 order is being made to restrict the take of water under unregulated river access licences and unregulated river (A Class, B Class and C Class) access licences in the Barwon-Darling unregulated river water source, in the management zones between Mungindi and Tilpa. The restriction will be in place from 17 April to 30 June 2019.
Rachel Connell, Executive Director, Department of Industry – Water
16 April 2019