Wilcannia Weir Replacement

To Whom it May Concern,
Thank you for the opportunity to comment on the Wilcannia Weir project.
We would be happy to discuss our submission in more detail or meet with you at any time.
Yours sincerely,
Julie McClure

Barwon-Darling Water Inc (BDW) is the peak body representing water users on the unregulated Barwon-Darling River. BDW is an independent, apolitical body, funded by its members.
It was set up to provide advice on the Barwon-Darling River to members and decision-makers, to assist with policy development, and to advocate on behalf of its members.
BDW membership is made up of local water user groups – including local government, irrigators, and basic right users. We represent all licence holders and water users on the Barwon-Darling – from Mungindi on the Queensland border to the Menindee Lakes.

BDW members have been involved in the water reform process, especially in relation to the unregulated Barwon-Darling River, for many years. This work has included:

• Co-operating with other stakeholders to create a set of environmental flow rules for the Barwon-Darling (through the first Barwon-Darling River Management Committee).
• Assisting in development of the Barwon-Darling Cap Management Strategy of 2007.
• Representations on the development of the Barwon-Darling Water Sharing Plan 2012.
• Representation on the Barwon-Darling Customer Advisory Group of WaterNSW.
• Working with DPIE Water on development of the Floodplain Harvesting Strategy; and
• Working as part of the Stakeholder Advisory Panel on development of the Barwon-Darling Water sharing Plan and Barwon-Darling Water Resource Plan 2020.

We have also been involved in discussions regarding water reform in the northern basin and specifically on the Barwon-Darling River since the mid 1990’s.

Our members welcome the opportunity to support the current Wilcannia Weir Replacement Project which we believe will provide the following benefits:



1. improved water security for the community of Wilcannia
2. enhanced cultural connection to the river in the Wilcannia area
3. improved water management of the weir pool
4. increased tourism opportunities and investment
5. better recreational amenity to walk, swim, picnic and fish, and
6. improved native fish migration.

Hi,

I am a water sector professional engineer with 28 years of experience including working with NSW, Federal and other state governments in conceptualization, designing and reviewing environmental and potable water management projects in riverine environments, including regulators and fishways.

I appreciate there has been significant effort, understanding and context invested into the selection of the current site and the resulting fishway arrangement. The weir and fishway is understandably a heavy civil infrastructure response to the need for meeting Wilcannia's water security requirements along with fish passage and many other objectives.

I propose that a subtle change in location of the weir could enable significant cost savings and risk mitigation for the construction and operation of the weir, regulating gates and the fishway.

There appears to be an opportunity to utilise an existing natural asset in the old river channel to the east for the fishway (via a longer and more natural channel) and move the weir to just upstream of where the old river channel discharges to create appropriate entrance conditions for the fishway adjacent to the weir gates on the left abutment (looking downstream). The fishway exit into the weir pool could be a split level rock ramp with two gates/channels – one for regular flow and one for drought storage level flow. It may need some earthworks to reopen the connection to the old river loop and for the fishway entrance downstream of the weir.

Please see the attachment showing the approximate location and alignment of the fishway (blue line).

I note this type of bypass fishway option has been proposed by other environmental agencies in other states as a desirable method of bypassing weirs and weir pools.

The benefits of this approach would include creating a new and diverse aquatic/riparian habitat in the old river channel and removing the need for a 100mx10m heavy civil asset in an active river system. It would also enable the regulator gates on the main weir to be located closer to the left abutment for operational and maintenance access.

Please note this is my own personal and professional opinion and I recognize it is offered without any understanding of the full project context inclusive of water management, other technical issues or requirements, nor any stakeholder, cultural, environmental issues or other project and site objectives, criteria or constraints.

I would be pleased to provide further clarity on this arrangement if required.

Regards
Gavin