IRRIGATION Agricultural Use of Water

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IRRIGATIONAgricultural Use of Water
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Amount of Water Used

• In western US states, 70 to 95 of the fresh
  water supply is dedicated to irrigation
• Globally an average of 70 of our fresh water use
  goes to irrigate agricultural crops
• This amount is expected to rise by 14 in the
  next three decades
• Consumptive water use (or irrigation efficiency)
  ranges from 30 to 90 depending upon the
  irrigation technology

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Sources of Water for Agriculture

• Direct (incident) rainfall
• Groundwater
• - Shallow aquifers
• - Deep aquifers
• Surface Water
• Redirecting runoff
• Stream diversions
• Storage in lakes and reservoirs

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Ways to Apply Irrigation Water

• Flood irrigation
• Furrow irrigation
• Sprinkler irrigation
• Drip irrigation

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Irrigation Infrastructure

• Historic/Traditional
• - Conveyance technologies ditches, conduits
• - Gravity flow, humans animals as a source of
  energy
• - Storage technologies ponds, lakes
• - Application technologies hand, syphon, flood
• Contemporary
• - Conveyance technologies
• - Pumping technologies
• - Storage technologies
• - Application technologies

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Challenges Facing Irrigated Agriculture

• Water quality concerns
• Groundwater mining and subsidence
• Water rights and policy issues
• Cost of developing water supplies
• Crop types and water supply changes
• Competition with other types of water use
• Changing technologies and traditional communities