At higher temperatures, evaporation rates increase and the water vapor leaves behind the total dissolved solids. Concentrations of the dissolved solids will increase, as the body of water becomes shallower. High total dissolved solid concentrations can harm aquatic life. Refer to the Total Dissolved Solids Information Sheet for more information. There is a natural fluctuation of waterway temperature from season to season, even day and night, and aquatic life can cope with these natural changes.
All species have a specific range of temperature in which they are adapted.
Fishermen know that trout like cold water streams, while other fish like carp and bluegills can tolerate warmer waters. If a stream changes temperature, organisms that cannot tolerate the change are stressed and must either reduce activity, move somewhere else, or in extreme cases, perish. Many life cycles of fish and aquatic insects are tied to water temperature. Temperature cues are used by these creatures to determine when to spawn, lay eggs, when the eggs will hatch, and when insect larvae will emerge from a stream to fly away. Thermal pollution can disrupt the timing of the life cycles, possibly causing eggs to hatch before sufficient food resources are available or larva to emerge when it is too cold atmospherically.