How does cold water pollution damage the environment?
The life-cycles of fish and other aquatic creatures are finely tuned to the natural daily and seasonal variations in temperature. Large volumes of cold water, lowering the overall temperature of water downstream from a dam, disturb the delicate ecological balance by creating an unseasonal environment that ecologists have compared to an ‘eternal winter’. In spring and summer the rising temperature of the water becomes an important environmental cue, triggering spawning of native fish. A release of cold water from a major dam can suppress spawning for up to 300 km downstream. The ability of native fish to reproduce, grow and maintain sustainable numbers is reduced. Introduced species such as carp flourish, competing with native fish for food and habitat. Some species of native fish can disappear from large sections of the river. Some examples of the effects of cold water releases on native fish in NSW include: • elimination of trout cod, Macquarie perch and freshwater blackfish from larg
