LET­TER TO THE ED­I­TOR Not grounded in re­al­ity

Shepparton News - Country News - - OPINION -

The last minute de­ci­sion to in­clude an ad­di­tional 450 Gl in the Mur­ray-Basin Basin Plan was based on a ‘blue sky think­ing’ work­shop, un­der­taken by ex­pe­ri­enced river op­er­a­tors and the Mur­ray-Dar­ling Basin Au­thor­ity, mod­el­ling a re­laxed con­straints 3200 Gl sce­nario, us­ing flows that have since been sig­nif­i­cantly re­duced due to the im­pacts that would have re­sulted from the sub­se­quent ma­jor flood­ing.

In early 2012 a work­shop of ex­pe­ri­enced river op­er­a­tors was re­quested by the basin of­fi­cial com­mit­tee ‘‘to em­brace blue-sky think­ing, and not to be con­strained by cur­rent ar­range­ments’’.

The work­shop fo­cused on in­ves­ti­gat­ing how to in­crease the fre­quency of over-bank flows in the Lower Mur­ray to achieve a tar­get event of up to 80 000 Ml/day down­stream of Eus­ton for up to 30 days ev­ery one-to-four to one-to-five years.

To achieve this tar­get event, the work­shop anal­y­sis stated the key fea­tures re­quired were sig­nif­i­cant in­flows from at least three of the four ma­jor river sys­tems, re­lax­ation of con­straints and pre-wet­ted or primed catch­ments with tim­ing of in­flows from each catch­ment be­ing cru­cial.

As ‘blue sky think­ing’ is ‘‘not grounded or in touch with re­al­i­ties of the present and does not in­clude the ne­ces­sity of deal­ing with prac­ti­cal­ity’’, the work­shop con­cluded that in­creased en­vi­ron­men­tal flows were fea­si­ble if con­straints were re­laxed, but in re­al­ity had no knowl­edge if con­straints could in fact be re­laxed, only not­ing so­cio-eco­nomic im­pacts would in­crease with higher flows.

The MDBA, in its hy­dro­logic mod­el­ling of the re­lax­ation of op­er­a­tional con­straints in the south­ern con­nected sys­tem (Oc­to­ber 2012), as­sumed a re­laxed con­straints sce­nario was pos­si­ble and used flow lev­els that have since been aban­doned due to the se­vere im­pacts that would be caused by the ma­jor flood flows that would be needed to achieve a flow of 80 000 Ml/day at the South Aus­tralian bor­der.

To achieve this flow, the MDBA mod­el­ling used a flow of 40 000 Ml/day in the Lower Goul­burn now re­duced to 20 000 Ml/ day and 40 000 Ml/day in the Yar­ra­wonga to Wakool con­straints area, now re­duced to 30 000 Ml/day.

De­spite this re­duc­tion in flows there has never been any re­vised mod­el­ling or anal­y­sis to as­sess the fact that th­ese re­duced flows mean the 450 Gl can not be de­liv­ered in the ini­tial pro­posed large vol­umes to SA.

The Ex­pe­ri­enced River Op­er­a­tors work­shop did, how­ever, note that a cost/ben­e­fit anal­y­sis would be needed.

Six years later, de­spite the MDBA also stat­ing in 2012, that ‘‘a cost/ben­e­fit anal­y­sis (in­clud­ing as­sess­ments of any third party im­pacts)’’ would be re­quired, there has been no cost/ben­e­fit anal­y­sis un­der­taken.

None of the above is­sues have been re­solved, but the Fed­eral De­part­ment of Agri­cul­ture and Wa­ter Re­sources is rush­ing for­ward with the at­tempted re­cov­ery of the 450 Gl, de­spite the fact it has no cer­tain knowl­edge or sci­en­tific grounds to show that this wa­ter can be de­liv­ered down­stream within the leg­is­lated guide­lines. — Jan Beer, Yea

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