I addressed a further letter to The Land in response to one which suggested an inconsistency between calling for better management of “The Barrages” and maintaining upstream dams.
“Andrew Brown’s (One dam question-Letters,June 13th) provides an ideal opening to explain precisely the difference between upstream water storages in the Murray Darling Basin and the damming of the estuary of the Murray River by way of The Barrages.
· Upstream storages are to meet human, animal and irrigation productive requirements. Whereas the Lower Lakes are not. These needs are met from the main stem of the Murray and in this sense there is no reason to attempt to keep the Lower Lakes unnaturally supplied with fresh water at all times.
· The SA Government obsession with using fresh water at all times means that the Lakes are deprived of their natural marine ecological nature; in droughts have the problem of acid sulphate soils when they dry out; evaporate massive volumes of fresh water from their huge shallow surface area and cause ever greater demands for precious fresh water from upstream. It was estimated that 740 to 1,100Gls of fresh water was lost to evaporation each year during the Millennium Drought in a failed attempt to keep the Lakes covered.
· A “barrage management/marine return solution” with the judicial use of oxygenated salt water, would allow the Lakes to be maintained at the artificial .75 metres above sea level (mainly for lifestyle boating purposes) and greatly reduce the demand for fresh water.