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# Quiz: Civil Engineering 7 May 2021

Quiz: Civil Engineering
Exam: DFCCIL
Topic: Irrigation & Hydrology

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 10 Minutes

Q1. Which one of the following defines Aridity index (AI)?
(a) AI=(PET-AET)/PET×100
(b) AI=PET/AET×100
(c) AI=AET/PET×100
(d) AI=(AET-PET)/AET×100
(where AET = Actual Evapotranspiration and PET = Potential Evapotranspiration)

Q2. A 3-hour storm on a small drainage basin produced rainfall intensities of 3.5 cm/hr, 4.2 cm/hr and 2.9 cm/hr in successive hours. If the surface runoff due to the storm is 3 cm, then the value of ϕ-index will be
(a) 2.212 cm/hr
(b) 2.331 cm/hr
(c) 2.412 cm/hr
(d) 2.533 cm/hr

Q3. Consider the following with respect to double – mass curve:
1. Plot of accumulated rainfall with respect to time in chronological orders.
2. Plot for estimating multiple missing rainfall data
3. Plot for checking the consistency of the rain-fall data
4. Plot of accumulated annual rainfall of a station vs. accumulated rainfall of a group of data
Which of these statements are correct?
(a) 1 and 3
(b) 2 and 3
(c) 3 and 4
(d) 1 and 4

Q4. Match List – I (Parameter) with List – II (Relatable term) and select the correct answer using the codes given below the lists:

Codes:

A          B          C          D

(a)        1          3          2          4

(b)        3          4          1          2

(c)        1          3          4          2

(d)        3          4          2          1

Q5. Which precipitation is caused by natural rising of warmer lighter air in colder and denser surroundings?
(a) Cyclonic precipitation
(b) Orographic precipitation
(c) Convective precipitation
(d) None of these

Q6. The type of rain-gauge commonly used in India for measuring rainfall is given by:
(a) weighing bucket type rain-gauge
(b) tipping bucket type rain-gauge
(c) floating type rain-gauge
(d) Simon’s rain-gauge

Q7. If specific yield of particular sand is 30% and its porosity is 50%, then the specific retention of the sand will be
(a) 80%
(b) 55%
(c) 40%
(d) 20%

Q8. A given piece of land is said to be waterlogged when:
(a) There is a water flowing on the land surface
(b) Capillary fringe reaches the root zone of plants
(c) Gravity drainage has ceased
(d) The permanent wilting point is reached

Q9. Loam is
(a) A mixture of sand, silt and clay
(b) A mixture of gravel, sand and silt
(c) An impure form of limestone
(d) Is a wind blow deposit

Q10. Lacey’s theory is applicable to flow
(a) Through pipes
(b) In concrete lined channels
(c) Over spillways
(d) In alluvial rivers and canals

Solutions

S1. Ans.(a)
Sol. ▭(Aridity Index (AI)=(PET-AET)/PET×100)
Where, AET = Actual Evapotranspiration
PET = Potential Evapotranspiration

S2. Ans.(d)
Sol. Total Precipitation (P) = Σ Intensity × duration
Total precipitation (P) = (3.5+4.2+2.9)×1 hr
= 10.6 cm.
Run off (R) = 3 cm.
ϕ=index=(P-R)/t
=(10.6-3)/3
▭(ϕ-index=2.533)
∵ the value of ϕ- index is smaller than all the 3 successive hours rainfall intensities.
Hence, ϕ-index= 2.533 cm\hr

S3. Ans.(c)
Sol. Double mass curve technique is followed to check the consistency of rain gauge record. It is used to correct the inconsistency of precipitation records. It is a graph plotted between accumulated annual rainfall of a station vs accumulated rainfall of a group of stations, this graph is known as double mass curve.

S4. Ans.(b)
Sol. Hyetograph → A plot between rainfall intensity and time.
Rainfall excess → Direct runoff hydrograph.
Isohyets → lines joining equal depth of rainfall.
Mass curve→ It is a plot between cumulative rainfall against time.

S5. Ans.(c)
Sol. Orographic precipitation → It is the result from lifting of warm moisture laden air masses due to topographic barriers like mountains.
Cyclonic precipitation → It is caused by lifting of air mass due to pressure difference.
Convective precipitation → It is caused by natural rising of warmer, lighter air in colder and denser surroundings.

S6. Ans.(d)
Sol.

• Simon rain gauge is a non-recording type of rain gauge and commonly used in India.
• Natural syphon rain gauge is adopted in India. It similar to weighing bucket rain gauge. It is recording type of rain gauge.
• Tipping bucket type of rain gauge is used for measuring rain in remote areas. It is recording type of rain gauge means produce continuous plot of rainfall against time.

S7. Ans.(d)
Sol. Given,
Specific yield (S_y) = 30%
Porosity (n) = 50%
Specific retention (SR) =?
S_y+S_R=n
30%+S_R= 50%
S_R=20%

S8. Ans.(b)
Sol. A given piece of land is said to be water logged when

• Capillary fringe reaches the root zone of plants.
• Due to rise of water table up to ground level.
• Area is full of salinity.

S9. Ans.(a)
Sol. Loam is a mixture of sand, silt and clay.

S10. Ans.(d)
Sol. Lacey’s theory is applicable to flow in alluvial rivers and canals.

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