Lake retention time

Lake retention time (also called the residence time of lake water, or the water age or flushing time) is the calculated average time that water (or a dissolved substance) spends in a lake. At its simplest this figure is the result of dividing the lake volume by the flow in or out of the lake. It describes the amount of time that is needed for a substance to flow in and out of a lake.

Lake Retention Time Media

• Illustration of the concept "lake retention time".png

  The lake retention time for a body of water with the volume 2,000 m³ (71,000 cu ft) and the exit flow of 100 m³/h (3,500 cu ft/h) is 20 hours.