Australian Journal of Ecology (2000) 25, 109-127
For further details on this and other research topics, contact Dr Richard Kingsford on: (tel) 02 - 9585 6488 or email - richard.kingsford@npws.nsw.gov.au
There is an ever-increasing body of research pointing to the detrimental impacts of river regulation on the natural environment. Dr Richard Kingsford, principal research scientist of the NSW National Parks and Wildlife Service, has just released a paper which reviews the ecological impacts of dams on floodplain wetlands in Australia. His case studies included the Barmah/Millewa forest, Chowilla floodplain, Macquarie marshes and Gwydir wetlands. All of these floodplain wetlands are listed under the international Ramsar treaty.
Australian floodplain wetlands are sites of high biodiversity which depends on flows from rivers. However river regulation has changed the natural hydrology of these wetlands, in some cases reducing flows, and in others, changing temporary systems into permanent ones. The diversion of water is a critical impact on wetlands. These changes alter the ecology of the wetlands and reduce total biodiversity. Negative changes observed over time include reduced aquatic vegetation cover and health, and declining water bird and fish populations. River regulation exacerbates (and is probably the major cause of) environmental problems such as salinity and blue-green algae outbreaks.
Australia has at least 446 major dams, with as much as 50% of floodplain wetlands on regulated rivers no longer receiving any flooding at all. Dr Kingsford stresses that to prevent further losses of vital floodplain wetlands, it is essential that plans to build more dams and divert more water from rivers should take the ecological needs of these into account. The loss of these wetlands and their extraordinary biodiversity will continue unabated until we recognise that flows to floodplain wetlands serve an ecological purpose and are not lost or wasted.