The Barmah Millewa Choke is in the MDBA’s sights as the pesky sand slug slithered its way out of the pages of gold mining history, to now find itself lodged fairly and squarely in the road of supplying the mounting downstream demands for the precious water stored in Hume and Dartmouth.

According to the MDBA, this particular sand slug must not be confused with the Cobram beach sand slug. Cobram local, Shane Bugge, seemed miffed at the MDBA’s denial of the Cobram sand slug existence.

“Do they (the MDBA) think that beach sand slugs only swim upstream?” said Shane.

“If the sand slug came down from the hills as they report, I wanna know how much sand they found in the recently drained Yarrawonga weir pool.

“Then, tell me, was it their slug travellin’ down or ours travelling up?”

The MDBA is now considering options to increase the capacity of downstream water delivery. It’s worth noting the MDBA use projected volumes for downstream of Yarrawonga, not the relative individual choke capacities.

These options set forth by the MDBA will be put forward to the Basin Officials Committee and the states via the Murray-Darling Basin Ministerial Council. During a presentation on ‘Delivery Risks and Shortfalls’ last week in Deniliquin, the MDBA ensured attendees that the last 20 years of horticultural plantations expansion, Victoria up 8,000Ha to 21,000Ha, NSW up 4,000Ha to 49,000Ha and up 22,000Ha to 62,000Ha, had no influence on the Barmah-Millewa Choke due to trade restriction, but little was said on the other classes of water that use the choke.

The Barmah Millewa Choke is utilised not only for productive water, but also for conveyance, dilution, planned environmental water and the South Australian allocation.

With 1,850 gigalitres required to flow to South Australia in the form of allocation and dilution, would the inflows and options of other rivers be an important consideration when considering Barmah Millewa Choke flows?

If, for example, the Darling is not providing the historical 39% of NSW commitments to SA allocation, where does the shortfall come from? Out of Murray storages and flow through the Barmah Millewa Choke?

Ironically, the Darling wasn’t in the terms of reference for a solution, in fact it wasn’t even on the MDBA’s map during the presentation.

How do we fix a problem in a connected system without considering all the contributing factors? It begs the question, what is in the terms of reference? 

There were six options considered with the limited scope ranging from dredging the choke, forcing more water down the Edward, using the broader Murray irrigation system, utilising mid-way storages to release water on demand or request Snowy Hydro to release water from Dartmouth down the Murrumbidgee.

A connected system with isolated ‘solutions’.

This article appeared in The Koondrook and Barham Bridge Newspaper, 28 July 2022.