Thursday, February 2, 2012

"Healthy River" model not acceptable for MDBasin Plan

The "Healthy River" Model of the Murray should be consigned to the dustbin. It is promoted by Don Henry, CEO of the Australian Conservation Foundation, as the solution to the problem of water allocation for the Murray Darling Basin. "Healthy river" is spin terminology. It has limited reality. It is more like simplistic eco-religious bunkum.

The objective of the MDBasin plan we are told is to have a "healthy river", says Don Henry. However, alternative objectives must be considered and priorities made when there are multiple objectives. Residents of the region should demand the major objective be "to maximize the agricultural production of the basin", which is already the major food bowl of Australia.

The healthy river idea is concerned with reducing draw-offs by irrigators by 3000 GL for environmental flows, which are supposed to flow into the Lower Lakes (viz., Lakes Alexandrina and Albert) so as to keep them fresh water and then flow out at the ocean mouth. Sounds wonderful, but the idea is not feasible in Australia which has extreme climatic conditions that vary from decade to decade. Such model healthy rivers may be found in the UK or NZ where there is plentiful rainfall year in and year out. .

Australia is different. We have the talent to study the system in all its complexity. First the geography ... what is the MDBasin? Does it include the Lower Lakes? How can a "river" be a "lake" ? A river is a river. A lake is a lake, by definition. The Lower Lakes are not a river but are (were) a sea water estuary that periodically gets flooded with fresh water. A study of the geological system reveals this to have been the case for the past 10,000 years. Prior to that during the last ice age the sea level was ca 120 meters lower and the Lower Lakes did not exist.

We have found out that in times of drought it has not been possible to maintain stable fresh water levels in the Lower Lakes from "environmental flows". The idea is crazy when there is an unlimited supply of sea water available from the Great Southern Ocean which unfortunately is kept out by the Barrages built at the ocean side of the lakes. Sea water floats your boat just as well or better than fresh water, and has a more plentiful supply of edible fish.

Any future MDBasin Plan must consider the merits of a sustainable sea water estuary system. This can be achieved by building Lock Zero at the lower end of the Murray (near Tailem Bend) to control the out flow of fresh water into the lakes. The whole Lower Lakes region including the Barrages needs redesigning by hydro-engineers to maximize its potential for the benefit of the community. More on this later. Allano