MEASUREMENT OF RAINFALL
MEASUREMENT OF RAINFALL

MEASUREMENT OF RAINFALL

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MEASUREMENT OF RAINFALL

  • Rainfall is the principal source of all waters.
  • It is expresse as the depth of water in centimetres which falls on a pucca, impermeable levelled surface.
  • The rainfall is measured with help of rain-gauges.
  • Rain-gauges may be automatic or nonautomatic.
  • Govt of India has approved use of non-automatic rain gauges at all the rain-gauge stations.
  • Following are different types of rain-gauges.
  1. Simon’s rain-gauge.
  2. Weighing bucket rain-gauge.
  3. Float type rain-gauge.
  4. Tipping bucket rain-gauge.

1. Simon’s Rain-gauge.

  • A typical Simon’s rain gauge is shown in Fig.  It is also known as non-recording type of rain-gauge, as it does not record the rate of

Simon’s Rain-gauge

  • rainfall at any moment but only collects rain water.
  • It consists of a funnel fixed at the top of a receiving bottle.
  • The receiving bottle is about 8 to 10 cm in diameter and is encased in the metal casing.
  • This bottle is fixed in the ground slightly below the ground level.
  • The rain water enters the bottle through the funnel and gets collected in the bottle.
  • The bottle can collect about 10 cm to 12 cm of rain.
  • Rainfall is recorded daily at 8 A.M.
  • by a man deputed for this purpose.
  • If the rain fall is too much and is likely to exceed the capacity of the bottle,
  • Then two or three intermediate readings are taken and their sum is recorded as the total rainfall during past 24 hours.

2. Float Type Rain-gauge.

  • It is a type of automatic rain-gauge.
  • The instrument consists of a funnel and a rectangular container.
  • The container consists of a float which remains connected to a pointer.
  • The pointer moves on a recording drum which is kept moving at such a rate that drum completes exactly one revolution in 24 hours.

Float Type Rain-gauge

3. Weighing Bucket Rain-gauge.

This rain-gauge consist receiver

Weighing buket type rain gauge

 

 

 

 

 

 

 

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