Water is pumped from rivers and underground water supplies for
use by rural towns, farms, industries and cities. Many rivers
also feed dams and reservoirs for public water supplies and hydro-power,
and are used as transport routes for boats.
While these activities provide economic and social benefits,
there are many adverse environmental effects caused by altering
the natural flow of rivers (river regulation). These include the
decline and loss of native species of plants and animals, encouragement
of habitats favourable to pest species (carp, gambusia and redfin),
declining water quality, and loss of amenity.
It is now widely recognised that changes to the flow regime have
severely degraded most, if not all, regulated rivers in some way.
The River
Murray highlights this. So much water is removed from the
river that less than 20% of the normal annual volume reaches the
river mouth at Goolwa.
River regulation in the Murray-Darling Basin is so severe that
giant river redgums which rely on frequent flooding are dying
and the Murray
cod is threatened.
Major efforts are now under way to understand the impact of river
regulation, and to develop strategies to restore and/or protect
the natural flow regime of rivers and creeks to improve the environmental
condition of our waterways.
