Average time for water to renew in rivers and to be completely replaced in the atmosphere

Range in rivers renewed once every 16 days: in the atmosphere completely replaced once every 8 days days
Organism Biosphere
Reference Pidwirny, M. (2006). “The Hydrologic Cycle”. Fundamentals of Physical Geography, 2nd Edition link bottom paragraph
Comments Bottom paragraph: "Water is continually cycled between its various reservoirs. This cycling occurs through the processes of evaporation, condensation, precipitation, deposition, runoff, infiltration, sublimation, transpiration, melting, and groundwater flow. Table 8b-2 describes the typical residence times of water in the major reservoirs. On average water is renewed in rivers once every 16 days. Water in the atmosphere is completely replaced once every 8 days. Slower rates of replacement occur in large lakes, glaciers, ocean bodies and groundwater. Replacement in these reservoirs can take from hundreds to thousands of years. Some of these resources (especially groundwater) are being used by humans at rates that far exceed their renewal times. This type of resource use is making this type of water effectively nonrenewable."
Entered by Uri M
ID 115098