MCQ
621. The rainfall at any place is described by
Its intensity
Its duration
Its frequency
All the above
622. In the derivation of Thiem's formula, Q = (S1- S2)/[2.3 log10(/) the following assumption is not applicable
The aquifer is homogeneous and isotropic
Flow lines are radial and horizontal
The slope of the water surface is too small
The well has been sunk up to the surface of the unconfined aquifer
623. The peak of a 4 hour flood hydrograph is 240 m3 /sec. If the rainfall excess is 80 mm and base flow which is constant is 40 m3/sec, peak of 4hours unit hydrograph will be
20 m3/sec
25 m3/sec
30 m3/sec
35 m3/sec
624. For the estimate of high floods in fan-shaped catchment, the formula used is
Dicken's formula
Ryve's formula
Inglis formula
None of these
625. The equation V (1000 ID10/60)×(1.8T+42) which is used for determining the velocity of ground water flow in metres per day is known as
Meinzer's formula
Slichter's formula
Darcy's formala
Hazen formula
626. Hydrograph is a graphical representation of
Surface run off
Ground water flow
Rain fall
Discharge flowing in the river
627. Discharge curve may be extended by logarithmic method if
Cross section of river is uniform
River is broader and shallower
River is of any type
None of these
628. Lining of irrigation channels
Increases the water-logging area
Decreases the water-logging area
Does not change the water logging ares
None of the above
629. The major resisting force in a gravity dam is
Water pressure
Wave pressure
Self-weight of dam
Uplift pressure
630. Izzard formula for the time of concentration in minutes for the plots having no channels, is (where Lo is the length of overland flow in metres and Kp rainfall intensity in cm/hour)
T= 111 b. L0 1/3/(Kp)2/3
Т= 222 bL10 1/2/(Kp)1/3
T= 333 b. LO/Kp
T= 111 b. LO 1/3/(Kp)2/5
631. For the upstream face of an earthen dam, the most adverse condition for stability of slope is
Sudden drawdown
Steady seepage
During construction
Sloughing of slope
632. When the reservoir is full, the maximum compressive force in a gravity dam is produced
At the toe
At the heel
Within the middle third of base
At centre of base
633. Indian Meteorological department uses the standard gauges whose collectors have apertures of
50 or 100 sq. cm area
100 or 150 sq. cm area
100 or 200 sq. cm area
250 or 500 sq. cm area
634. An aggrading river is a
Silting river
Scouring river
Both silting and scouring river
Neither silting nor scouring river
635. Pick up the correct statement from the following:
Yield of a drainage basin is the run off at any time
Yield of a drainage basin is the run off over long periods
Yield of a drainage basin is expressed as surface run off per year
Run off is expressed as total volume per day
636. Seepage through embankments in an earthen dam is controlled by
Drainage filters
Relief wells
Drain trenches
Provision of downstream berms
637. In the estimate of design flood, Dickens assumes that high flood in cumecs, is proportional to catchment area raised to the power
1/4
1/2
3/4
2/3
638. The main function of a divide wall is to
Control the silt entry in the canal
Prevent river floods from entering the canal
Separate the under-sluices from weir proper
Provide smooth flow at sufficiently low velocity
639. The sensitivity of a rigid module is
Zero
Between zero and one
1
Infinity
640. The stage of river carrying a discharge of Q m/sec at a point is 10 m and slope of water surface is (1/4000). The discharge of a flood same point and same stage of 10 m with a water surface slope of (1/1000) will be
3/sec
0.5 Q m3/sec
2 Q m3/sec
4 Q m3 sec