GLOBAL WATER SOURCE AND VOLUME Water Source Water volume (in cubic miles) Percent of total water 1.Oceans 317,000,000 97.24% 2.Icecaps, glaciers 7,000,000 2.14% 3.Groundwater 2,000,000 0.61% 4.Fresh-water lakes 30,000 0.009% 5.Inland seas 25,000 0.008% 6.Soil moisture 16,000 0.005% 7.Atmosphere 3,100 0.001% 8.Rivers 300 0.0001% 9.Total 326,000,000 100% SOURCE: USGS, 1984, The Hydrologic Cycle- Pamphlet
Period of Renewal (residence times) World Ocean 2500 years Ground water 1400 years Polar ice 9700 years Mountain glaciers 1600 years Ground ice 10000 years Lakes 17 years Bogs 5 years Soil moisture 1 years Channel network 16 days Atmospheric moisture 8 days Biological water several hours
Water Budget Income –PRECIPITATION Rain, snow, condensation…. Outgo: –EVAPOTRANSPIRATION Evaporation and Transpiration infiltration, runoff
Water Budget Surplus: –More income than outgo During rainy season, lots of rain and humidity During winter, not much evaporation or transpiration Deficit: –More outgo than income During dry season, lots of evaporation During summer, lots of plants
Water Quality Water is cleaned or filtered as it moves through the aquifer, therefore groundwater is generally clean. The deeper the well the farther from a pollution, therefore cleaner. Groundwater moves very slowly, therefore pollution can take many years to flush out.
Natural Water Problems Hard Water Salty Water No Water Stinky Water
In which direction does groundwater move? Like surface water, groundwater moves down hill, not downward.
How does water leave the ground? Evapotranspiration –Evaporation –Transpiration Springs Geysers Wells Artesian Wells
Why is vegetation good? Splash Erosion –The drop impacts loosen the soil Sheet Erosion –Water running over the surface carries away the topsoil Less Infiltration –More runoff means less groundwater recharge