Water levels below sealevel are unnatural
Water levels below sea level are the most unnatural and environmentally damaging feature of the current crisis – created by the unnatural intervention of the barrages which prevent the historical maintenance of sea level within the lakes/estuary system in these times of extreme drought and resultant very low river flows.
by Trevor Harden
4 May 2010
While ‘freshwater only’ activists argue about the degree to which seawater would have influenced the salinity mix of the estuary during drought periods before European settlement, and claim that fresh water is the only ‘natural’ state of this estuarine system, they are apparently willing to accept these vast expanses of windblown sand, the exposure of acid sulphate soils and the physical restructuring of historical shorelines as a preferred and more natural option than the creation of a living estuary.
To promote the vegetation of these exposed lake beds as a management ‘solution’ when the strategy is clearly flawed and has demonstrably failed to remedy the problems of windblown erosion and deposition over large areas is a waste of public money and effort if a viable and much more environmentally friendly alternative is readily available.
To continue to refer to these projects as ‘revegetation’, with all the reassuringly positive connotations that this term generates when used in the context of restoring a damaged environment to its natural state; is grossly misleading in this context where these lakebeds have always been underwater – and are now in this unprecedented exposed state only because of the barrages. It would seem that ‘freshwater only’ ideology is not inconsistent with terminology that misleads and misrepresents the facts.
There is no place for extremist environmental ideology in the planning and management of this crisis. Action must be evidence based and the environmental values of a living estuary at sea level, (with salinities across the system determined by the balance between tidal influences and freshwater flows from the River Murray), must be considered objectively on its merits against the currently proposed long term drought management strategies of low water levels and vegetation/bioremediation.
The restoration of sufficient freshwater flows to ensure the health of the Murray/Darling system is a separate, albeit closely related, issue and success there will greatly assist the management and health of the Coorong and Lower Lakes – but to persist with a ‘freshwater only’ range of options for the Lower Lakes is a flawed strategy already proven to be totally inadequate when extreme drought reduces river flows to current levels.