in this presentation you will know about following head line point. 1>Illustration of various types of rain-gauges. 2>Advantaged and disadvantages of various types of gauges.

2. MEHRAN UNIVERSITY OF ENGINEERING AND
TECHNOLOGY,
SHAHEED ZULFIQAR ALI BHUTTO CAMPUS
KHAIRPUR MIRs’
DEPARTMENT OF CIVIL ENGINEERING
Name: Faizan Noor
Topic: Illustration of various types of rain-
gauges.
Advantaged and disadvantages of various types
of gauges.
Date of exam: 24-07-2020

3. TOPICS
Illustration of various types of rain-gauges.
Advantaged and disadvantages of various types of gauges.

4. TYPES OF RAIN-GAUGES
Following are the main types of rain-gauges used for
measurement of rainfall.
Non-automatic / Non-recording Rain-gauge
 Symon’s Rain-gauge
Automatic / Recording Rain-gauge
 Weighing Bucket Rain-gauge
 Tipping Bucket Rain-gauge
 Float type Rain-gauge

5. NON-AUTOMATIC (NON-RECORDING)
RAIN-GAUGE
 These are called non-recording rain gauges because they do
not record the rain but only collect the rain.
 The collected rain is then measured by means of graduated
cylinders so as to directly represent the rainfall volume in cm of
water depth, i.e.
Depth of rain water in cm =
Note: The amount of precipitation/rainfall is expressed as the
depth in cm or inches.
3
2
Volume of water collected in cm
Area of aperatureof the guage in cm

6. SYMON’S RAIN-GAUGE
• Most common type of non-automatic rain-gauge.
• Consists of cylindrical vessel 127 mm (5”) dia with a
base enlarged to 210 mm (8”) dia.
• The top section is a funnel provided with circular
brass rim exactly 127 mm (5”) internal dia.
• The funnel shank is inserted in the neck of receiving
bottle which is 75 to 100 mm (3 to 4”) dia.
• Capacity of bottle is 75 to 100 mm of rainfall.
• The rain-gauge is placed in concrete block
60cm×60cm×60cm (2’×2’×2’).
• The rim should be 305 mm (12”) above the ground
surface.
• Water contained in the bottle is measured by suitably
graduated measuring glass, with an accuracy up to 0.1
mm.
• During a heavy rainfall, the rain should be measured 3
or 4 times in a day.

7. AUTOMATIC (RECORDING) RAIN-
GAUGE
• Gauges which can give permanent and automatic
rainfall record without any bottle reading.
• Man has not to go to the gauge to measure the
amount of rain fallen.
• There is mechanical arrangement by which the total
amount of rain fallen, since the record was started,
gets recorded automatically.
• The gauge thus produces a record of cumulative rain
vs. time in the form of graph known as Mass Curve of
rain fallen.

8. MEASUREMENT OF RAINFALL BY
AN AUTOMATIC (RECORDING)
RAIN-GAUGEIn general, automatic rain-gauge consists of
rotating drum with a graph paper fixed around
it.
There is pen in contact with graph paper, which
moves up with the collected rain, and thus
recording cumulative rain, with the passage of
time.
These are of three types
1. Weighing Bucket Rain-gauge
2. Tipping Bucket Rain-gauge
3. Float Type Rain-gauge

9. 1.WEIGHING BUCKET RAIN-GAUGE
• Consists of a receiver
bucket supported by a
spring or lever balance
or any other weighing
mechanism.
• The movement of
bucket due to its
increasing weight is
transmitted to a pen
which traces the record
on a clock driven chart.

10. 2.TIPPING BUCKET RAIN-GAUGE
Consists of 30 cm dia sharp edge
receiver.
At the end of receiver funnel is
provided.
Under the funnel a pair of buckets are
pivoted (the central point which
balances) in such away that when one
bucket receives 0.25 mm (0.01”) of
rainfall it tips (to fall or turn over),
discharging its contents into reservoir
bringing other bucket under funnel.
Tipping of bucket completes an electric
circuit causing the movement of pen to
mark on clock driven revolving drum
which carries a record sheet.

12. 3.FLOAT TYPE RAIN-GAUGE
• Working is similar to weighing gauge
bucket.
• Funnel receives the rain water which is
collected in rectangular container.
• Float is provided at the bottom of
container.
• Float is raised as the water level rises in
the container.
• Movement of float is being recorded by
a pen moving on recording drum
actuated by clock work.
• When the water level in the container
rises so that float touches the top, the
siphon comes into operation, and release
the water; thus all the water in the box is
drained out.

13. ADVANTAGES OF RECORDING GAUGE
OVER THE NON-RECORDING GAUGE.
• In recording gauge rainfall is recorded
automatically & therefore, there is no necessity of
any attendant.
• Recording rain-gauge gives the intensity of
rainfall @ any time while the non-recording
gauge gives the total rainfall in any particular
interval of time.
• As no attendant is required such rain-gauge can
be installed in far–off places also.
• Possibility of human error is obviated.

14. DISADVANTAGES OF RECORDING
GAUGE OVER THE NON-RECORDING
GAUGE.
• It is costly in comparison with non-recording gauge.
• Fault may be developed in electrical or mechanical
mechanism or recording the rainfall.