water resources, use, policy. water quantity quantity sources & distribution sources &...
Post on 22-Dec-2015
221 views
TRANSCRIPT
WaterWater
• QuantityQuantity
• Sources & DistributionSources & Distribution
• Hydrological Cycles & Ecosystem Hydrological Cycles & Ecosystem HealthHealth
• Patterns of use & recuperationPatterns of use & recuperation
• IrrigationIrrigation
• DamsDams
How Much Water is There?How Much Water is There?
• Though most of the earth is covered Though most of the earth is covered by water, only 2.6% of all the water by water, only 2.6% of all the water is freshwateris freshwater
• If we scaled all the water on the If we scaled all the water on the planet to = 100 gallons then all the planet to = 100 gallons then all the freshwater would = 9.6 teaspoons!freshwater would = 9.6 teaspoons!
Dynamic of Rivers and Dynamic of Rivers and OceanOcean
• Infiltration of seawater depends upon Infiltration of seawater depends upon strength of freshwater current and volumestrength of freshwater current and volume
• In summer season greater seawater In summer season greater seawater penetrationpenetration
• In drought years, even greater penetrationIn drought years, even greater penetration
• E.g., saltwater wedge from Gulf of Mexico E.g., saltwater wedge from Gulf of Mexico known to penetrate the Mississippii more known to penetrate the Mississippii more than 200 milesthan 200 miles
Dynamic of Rivers and Dynamic of Rivers and OceanOcean
• Infiltration of seawater can have Infiltration of seawater can have serious consequences for agriculture, serious consequences for agriculture, ranching and drinking waterranching and drinking water
• Exacerbated by human reduced Exacerbated by human reduced flows in rivers and watershedsflows in rivers and watersheds
Prevention of Flooding bydykes, levees, channelization, river
diversion is expensive and usually leads to increased erosion downstream
Humans Living in Flood Humans Living in Flood ZonesZones
• Billions of $US spent annual on flood relief Billions of $US spent annual on flood relief and insuranceand insurance
• Floods beneficial for agricultureFloods beneficial for agriculture
• Farming yes, but permanent residences?Farming yes, but permanent residences?
Missouri River 1992 Missouri River 1993
Colorado R. Water & Colorado R. Water & AgricultureAgriculture
• The Imperial Valley of California is one of the major producing regions of fruits and vegetables in the US
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Delta of the Colorado
River:
BONE DRY!
IrrigationIrrigation• Takes water from rivers or Takes water from rivers or
aquifersaquifers
• In US > 21 million hectaresIn US > 21 million hectares
• Increased rate of water loss to Increased rate of water loss to evaporationevaporation
• Costs do not include depletion Costs do not include depletion of freshwater resourcesof freshwater resources
Depletion of Depletion of aquifersaquifers
Ogallala Ogallala AquiferAquifer
Should we be Should we be irrigating the irrigating the most arid lands most arid lands in the USA???in the USA???