# Water Resources Engineering (Test 4)

## Gate Exam : Ce Civil Engineering

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Q.1
The type of flood routing (Group I) and the equation(s) used for the purpose (Group II) are given below.
Group I                                            Group II
P. Hydrologic flood routing              1. Continuity equation
Q. Hydraulic flood routing               2. Momentum equation
3. Energy equation
The correct match is
A. P - 1; Q - 1, 2 & 3
B. P - 1; Q - 1 & 2
C. P - 1 & 2; Q - 1
D. P - 1 & 2; Q - 1 & 2
Explaination / Solution:
No Explaination.

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Q.2
The relationship among specific yield (Sy), specific retention (Sr) and porosity (η) of an aquifer is
A. S= Sη
B. S= Sr η
C. Sη - Sr
D. S= S+ 2η
Explaination / Solution:
No Explaination.

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Q.3
One hour triangular unit hydrograph of a watershed has the peak discharge of 60 m3 /sec cm at 10 hours and time base of 30 hours. The Φ index is 0.4 cm per hour and base flow is 15 m3 /sec.
If there is rainfall of 5.4 cm in 1 hour, the ordinate of the flood hydrograph at 15th hour is
A. 225 m3 /sec
B. 240 m3 /sec
C. 249 m3 /sec
D. 258 m3 /sec
Explaination / Solution:
No Explaination.

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Q.4
The relationship between porosity (η), specific yield (Sy) and specific retention (Sr) of an unconfined aquifer is
A. S+ S= η
B. S+  η = Sr
C. Sr η = Sy
D. S+ Sr + η = 1
Explaination / Solution:
No Explaination.

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Q.5
Determine the correctness or otherwise of the following Assertion [A] and the Reason [R] :
Assertion :The crown of the outgoing larger diameter sewer is always matched with the crown of incoming smaller diameter sewer.
Reason : It eliminates backing up of sewage in the incoming smaller diameter sewer
A. Both [A] and [R] are true and [R] is the correct reason for [A]
B. Both [A] and [R] are true but [R] is not the correct reason for [A]
C. Both [A] and [R] are false
D. [A] is true but [R] is false
Explaination / Solution:
No Explaination.

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Q.6
A rectangular channel 6.0 m wide carries a discharge of 16.0 m3/s under uniform flow condition with normal depth of 1.60 m. Minning’s ‘n’ is 0.015.
The longitudinal slope of the channel is
A. 0.000585
B. 0.000485
C. 0.000385
D. 0.000285
Explaination / Solution:
No Explaination.

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Q.7
Group I lists a few devices while Group II provides information about their uses. Match the devices with their corresponding use. A. P - 1; Q -2; R - 3; S - 4
B. P - 2; Q - 1; R - 4; S- 3
C. P - 4; Q - 2; R - 1; S - 3
D. P - 4; Q - 3; R - 2; S – 1
Explaination / Solution:

Aneometer → wind speed Hygrometer → water vapour content of air Pilot tube → flow velocity at a specific point in the flow stream Tensionmeter → Capillary potential of soil water

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Q.8
The base width of an elementary profile of a gravity dam of height H is b. The specific gravity of the material of the dam is G and uplift pressure coefficient is K. The correct relationship for no tension at the heel is given by
A. B. C. D. Explaination / Solution:
No Explaination.

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Q.9
For a 2-D flow field, the stream function ψ is given as ψ = 3/2(yx2). The magnitude of discharge occurring between the stream line passing through points (0, 3) and (3, 4) is
A. 6 units
B. 3 units
C. 1.5 units
D. 2 units
Explaination / Solution:

Q = ψ1 − ψ2 = 3/2(9-0) - 3/2(16-9) = 3 units
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Q.10
In an aquifer extending over 150 hectare, the water table was m20 below ground level. Over a period of time the water table dropped to m23 below the ground level. If the porosity of aquifer is 0.40 and the specific retention is 0.15, what is the change in ground water storage of the aquifer?
A. 67.5 ha-m
B. 112.5 ha-m
C. 180.0 ha-m
D. 450.0 ha-m