Case Study: Irrigation

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Case Study Irrigation

• By Amelia Stannard and Ben Powell

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Examples in the World Irrigation

• There are many different types of irrigation.
• These are surface, localised, drip or trickle,
  sprinkler, centre pivot, lateral move and sub
  irrigation.

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Examples in the World Irrigation

• Surface irrigation
• In surface irrigation systems water is moving
  over the land by simple gravity flow in order to
  wet it and to infiltrate into the soil. They can
  be subdivided into furrow or basin irrigation.

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Examples in the World Irrigation

• Localised irrigation
• Localised irrigation is a system where water is
  distributed under low pressure through a pipe
  network and applied as a small discharge to each
  plant. Drip irrigation, spray or micro-sprinkler
  irrigation and bubbler irrigation belong to this
  category of irrigation methods.

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Examples in the World Irrigation

• Drip or Trickle irrigation
• Water is delivered at or near the root zone of
  plants, drop by drop. This type of system can be
  the most water-efficient method of irrigation, if
  managed properly, since evaporation and runoff
  are minimized.

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Examples in the World Irrigation

• Sprinkler irrigation
• In sprinkler or overhead irrigation, water is
  piped to one or more central locations within the
  field and distributed by overhead high-pressure
  sprinklers or guns.
• A system using sprinklers, sprays, or guns
  mounted overhead on permanently installed piping
  is often referred to as a solid-set irrigation
  system.

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Examples in the World Irrigation

• Centre pivot irrigation
• Center pivot irrigation is a form of sprinkler
  irrigation. The system moves in a circular
  pattern and is fed with water from the pivot
  point at the center of the arc.

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Examples in the World Irrigation

• Lateral move Irrigation
• Lateral move is more labour intensive than centre
  pivot but less expensive making this system more
  popular with lesser affluent farmers.
• These systems are generally found in hilly or
  mountainous regions.

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Examples in the World Irrigation

• Sub Irrigation
• Sub-irrigation has been used for many years in
  areas with high water tables.
• It is a method of artificially raising the water
  table to allow the soil to be moistened from
  below the plants' root zone.
• Often these systems are located on permanent
  grasslands in lowlands or river valleys. A system
  of pumping stations, canals, weirs and gates
  allows it to increase or decrease the water level
  in a network of ditches and the control the water
  table.

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Examples in the world Egypt

• Rainfall is scarce in Egypt. Even the small
  amount which normally occurs over the Delta comes
  during the winter when crop demands are low.
• Egypts farmlands are almost entirely dependent
  on irrigation from the River Nile.
• The last century witnessed a radical change in
  Egyptian irrigations methods.
• The ancient system of basin irrigation and
  cultivation of one crop per year has been
  superseded by perennial irrigation.

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Examples in the World Egypt

• Without irrigation the River Nile would flood
  each year during summer, as waters from East
  Africa flowed down the river.
• These floods brought nutrients and minerals that
  made the soil around the Nile fertile and ideal
  for farming. As the population along the river
  grew, there came a need to control the flood
  waters to protect farmland and cotton fields.
• In a high-water year, the whole crop may be
  entirely wiped out, while in a low-water year
  there was widespread drought and famine.

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Examples in the World Egypt

• In 1902 the Low Aswan Dam was built under British
  construction.
• The Low Aswan Dam is a gravity dam.
• The design though was found inadequate and the
  dam was further raised in two stages. The first
  in 1907-1912 and the second in 1929-1933.
• When it nearly overflowed again in 1946 it was
  decided to build a new dam, the High Aswan Dam,
  and it is because of this dam that much of Egypt
  is now under irrigation.

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Examples in the World Egypt
The Low Aswan Dam
The High Aswan Dam