Introduction to Irrigation Engineering

1
Introduction to Irrigation Engineering

• Chapter 1

2
What is Irrigation Engineering

• Irrigation is the application of water to the
  soil for the purpose of supplying the moisture
  essential for plant growth

3
Historical perspectives

• Ancient civilizations rose over irrigated areas
• Egypt claims having the world's oldest dam, 108m
  long, 12m high, built 5,000 years ago
• 6,000 years ago, Mesopotamia supported as many
  as 25 million people.
• The same land today with similar population
  depends on imported wheat for food

4
Challenges for Irrigation and drainage engineers

• Depletion of natural resources (soil and water)
• Salinization of soil
• Lower productivity of soil tax records from
  Mesopotamia barely yields were 2500L/ha, now only
  ¼ to ½ this value.
• Dissertification

5
Irrigation technology

• Hi-tech control tensiometers, controls and
  automation of irrigation and water application.
• Use of remote sensing for irrigation scheduling
  and prediction of yield
• New job oppurtunities

6
Role of Civil Engineers

• The supply of water at farm turnout
• Water storage
• Water conveyance
• Supplying water WHEN needed and by the QUANTITY
  needed irrigation scheduling
• Drainage surface and sub-surface

7
Purposes of Irrigation

• Providing insurance against short duration
  droughts
• Reducing the hazard of frost (increase the
  temperature of the plant)
•  Reducing the temperature during hot spells
•  Washing or diluting salts in the soil
•  Softening tillage pans and clods.
•  Delaying bud formation by evaporative cooling
•  Promoting the function of some micro organisms

8
Sources of Moisture for Plant Growth

• Precipitation (includes rain, hail, snow)
• Frequency
• Intensity
• Depth
• Atmospheric water
• Flood water
• Ground water

9
Terms

• Deficit irrigation
• Supplemental irrigation