A big flush of fresh wa­ter

Shepparton News - Country News - - NEWS -

The Goul­burn River is about to get a big dose of fresh wa­ter as part of the Goul­burn Bro­ken Catch­ment Man­age­ment Au­thor­ity’s pro­gram for en­vi­ron­men­tal wa­ter­ing.

De­pend­ing on nat­u­ral con­di­tions, in­clud­ing rain­fall, the CMA could be ap­ply­ing up to 60 Gl of wa­ter.

The ex­tra flow is de­signed to pro­vide plants on the banks of the lower Goul­burn River a well-needed late sum­mer drink and en­cour­age golden perch to mi­grate from the Mur­ray River to the Goul­burn.

Goul­burn Bro­ken CMA en­vi­ron­men­tal wa­ter man­ager Si­mon Casanelia said an en­vi­ron­men­tal wa­ter ‘‘fresh’’ would be de­liv­ered along the Goul­burn River be­low the Goul­burn Weir from late Fe­bru­ary and through March.

‘‘The an­nual mon­i­tor­ing that we’ve been con­duct­ing shows that us­ing en­vi­ron­men­tal wa­ter to ‘top up’ the wa­ter that is be­ing de­liv­ered to ir­ri­ga­tors and other users at this time of the year has helped bank-sta­bil­is­ing plants es­tab­lish along the lower Goul­burn,’’ Mr Casanelia said.

‘‘And, be­cause of this vege­ta­tion, we saw far less bank slump­ing and ero­sion dur­ing the nat­u­ral flood­ing we ex­pe­ri­enced late last year than we did dur­ing 2010 to 2012.’’

Wa­ter for the in­creased flow is due to be re­leased from Goul­burn Weir from Fe­bru­ary 26, with the peak of about 4600 Ml/day reach­ing McCoy’s Bridge by March 9.

The flow will be well be­low mi­nor flood level. In the event of heavy rain, the tim­ing and size of the en­vi­ron­men­tal flow could change.

The wa­ter will come from an In­ter-Val­ley trans­fer and from Com­mon­wealth and Vic­to­rian en­vi­ron­men­tal wa­ter.

If the wa­ter from the trans­fer is low, about 60 Gl of en­vi­ron­men­tal wa­ter could be used, or if the wa­ter avail­able from the trans­fer is high, then only 14 Gl may be re­quired.

The CMA said th­ese es­ti­mates were as­sum­ing no rain­fall and no in­flows from trib­u­taries such as the Bro­ken River, so they were at the high­est pos­si­ble range of wa­ter re­quired to be re­leased.

The en­vi­ron­men­tal wa­ter will im­prove wa­ter qual­ity and pro­vide food and shel­ter for wa­ter bugs and na­tive fish.

‘‘Dur­ing the hot, dry weather it’s im­por­tant to have refuge pools for aquatic an­i­mals,’’ Mr Casanelia said.

‘‘Im­proved wa­ter qual­ity will also help cray­fish, shrimps, wa­ter bugs and na­tive fish con­tinue to re­cover after the black­wa­ter event ear­lier this year.

‘‘We’re keen too to see if the higher flows in the Goul­burn River at this time of the year at­tract na­tive fish, par­tic­u­larly golden perch, to move here from the Mur­ray.’’

In past years, en­vi­ron­men­tal wa­ter de­liv­ered in spring has trig­gered golden perch spawn­ing in the Goul­burn River.

‘‘While we’ve found lots of eggs in the Goul­burn, only low num­bers of young fish have been re­ported,’’ Mr Casanelia said.

‘‘The rea­son for this is un­clear, although it seems highly likely that the eggs and ju­ve­nile fish move down­stream into the Mur­ray. We hope the higher flows in the Goul­burn at this time of the year will at­tract more young perch back into the Goul­burn.’’

As part of the mon­i­tor­ing pro­gram funded by the Com­mon­wealth En­vi­ron­men­tal Wa­ter Of­fice, fish ecol­o­gists from the Arthur Ry­lah In­sti­tute will use acous­tic track­ing to de­ter­mine if fish move into the Goul­burn from the Mur­ray in re­sponse to the fresh. For more in­for­ma­tion, visit www.gbcma.vic.gov.au

Re­freshed . . . The Goul­burn will get a fresh flush of wa­ter soon.

Help­ing hand . . . Golden perch could ben­e­fit from the ex­tra flow planned.

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