My interest in the subject became even greater when I found myself Chairman and CEO of an agricultural company whose interests included an irrigation business growing cotton on the Darling River upstream and downstream of Bourke.
My first impressions as I familiarised myself with this business were:-
- The human characteristic of always seeking to blame somebody for water shortages and the reluctance to attribute these shortages to natural factors.
- The meaningless of average statistics when the spreads around the average are enormous.
- The failure of water authorities to appreciate the massive magnitude of the big events, and their frequency, albeit irregularity.
- The persistence of these authorities to maintain an attitude of "we must determine how much water for this or that" when "we" have very little control. Man fiddles at the edges. Nature dominates.
For the MDB Authority to ask CSIRO to come up with single Annual Volumetric Limits (AVL's) for each of the significant rivers in the basin is a stupid question from people who clearly do not appreciate the above facts. Limits should be based on percentages of actual flows. Note that from the big events , a very small percentage can amount to a huge amount of water. This massive variability cries out for more dams to spread the benefits.
The 2016 'big wet' winter, following an extremely dry period with no flow in the Darling River below the Menindee Lakes, is a wonderful demonstration of the key characteristic with which we live in this fascinating country. The volume of water that has flowed past Bourke in the last fortnight now exceeds the volume attributed to Sydney Harbour-500,000 megalitres or 500 gigalitres.