1Water Cycle, Groundwater, Water PollutionHydrologic Cyclehttp://www.mnforsustain.org/water_climate_global_water_cycle_study.htmDistribution/Cycle AnimationWater Cycle• 86% of evaporation from sea surface• 14% of atmospheric moisture from EVAPOTRANSPIRATION• 78% of precipitation on sea surface• 22% of water precipitated falls on land http://meted.com/mesoprim/mpradfog/print.htmWater CycleWater Cycle• Less that 3% of Earth’s water is on land• Over ¾ of that is in glacial ice• Most of the rest is stored as groundwater–(some groundwater is saline)Groundwater• Precipitation infiltrates Earth’s surface• Largest reservoir of liquid fresh water• Drinking water source for half of U.S.Water sources in OregonGroundwaterSurface waterhttp://www.deq.state.or.us/wq/dwp/dwp.htmGroundwater• Contributes to stream flow• ‘Universal solvent’• Dissolves some rock types–Limestone (CaCO3)– Salts (NaCl, KCl)– Gypsum (CaSO4)2Groundwater Source• First becomes ‘soil moisture’– Plants use it– Some evaporates directlySome sinks down–Some sinks down• Infiltration• ‘Groundwater’ is storedGroundwater Terms• Zone of saturation• Water table• Zone of aerationGroundwater terms diagramGroundwater Storage • Porosity of rock– Spaces between sand grains– Cracks in crystalline rockDissolved cavities–Dissolved cavities• Permeability– Allows water to move– Interconnection of pore spaces• Stored in AQUIFER– Porous and permeable rock• Trapped by AQUITARDIblkGroundwater Storage–Impermeable rock– Clay, shaleGroundwater Movement• Very slowly—– Small openings– High surface tensionPf tt fl•Pressure forces water to areas of lower pressure– Hydraulic gradient– Hydraulic headGroundwater movement diagramSprings• Where water table intersects ground surfacePhoto of cliff springs3Carlsbad CavernsDrip stone• Soda straws•Curtains• Angel wings• Organ pipes• Cave pearls• Stalactites• StalagmitesArecibo, Puerto Rico: Radio Telescope in SinkholeKarst drainage of manmade lake in MissouriKarst towering butteshttp://en.wikipedia.org/wiki/YangshuoThailand Karst Towershttp://www.siue.edu/GEOGRAPHY/ONLINE/Gillespie.htm4Wells Wells after drawdown Artesian wellsOgallala supported agricultureOgallala Aquifer• Exploited in Great Plains agriculture• Water table droppeddropped• Recharge rate lowSan Joaquin Valley subsidenceNot able torecover dueto
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