Temperature
back to the list of parameters

Water temperature directly affects biological and chemical processes. Some fish species, such as steelhead trout, prefer colder waters, others prefer warmer water. For example, trout need temperatures lower than 19 °C (66 °F) to do well and lower than 9 °C (48 °F) to spawn, but can stand temperatures as high as 24 °C (75 °F) for short periods; for catfish these limits are 32 °C (90 °F), 27 °C (81 °F) and 35 °C (95 °F). Water temperature affects the oxygen content of water - the higher the temperature the less oxygen it can hold. Fish and benthic macro-invertebrates will move about in the stream to find their optimal temperature. Temperature can be affected by many human activities. Examples include:

Building dams or artificial stream channels alters the flow rate, which in turn can affect temperature.

Removing streamside vegetation reduces shade which would normally keep the water cool.

Construction or other human activities near streams can increase sedimentation, which traps more heat in the water.

Water effluent from industrial sources such as power plants can drastically change water temperatures.

Observations made on Stream Team about temperature: