1. Residence Time

2. 100 gallons1 gallon/min

3. Residence Time of Water Ice caps: 10,000 to 200,000 years Deep groundwater: 3000-10,000 years Oceans: 3000-3500 years Shallow groundwater: 100-200 years Valley glaciers: 20-100 years Fresh water lakes: 50-100 years Atmosphere: 5 to 15 days Living organisms: hours to days

4. Residence Time of Water Evaporation from the ocean is about 0.03% of the total ocean volume (1.35 billion cubic km) per year.

5. Residence Time of Water Evaporation from the ocean is about 0.03% of the total ocean volume (1.35 billion cubic km) per year. About 76% of this water precipitates directly back into the ocean. The remaining 24% falls on land.

6. February 3

8. Glen Canyon dam issues Will fill with sediment 1/10-1/20 of the water soaks into the rock layers under the reservoir Evaporation from lake surface equivalent to about 1/20 of the flow of the river Water is absorbed by trees and bushes along the river– another 1/20 of the river Water leaving the reservoir is very cold– changes life below dam Recreation has changed– scenic canyon flooded with water.