Multiple Choice Questions and Answers (MCQs) on Hydrology and Water Resources Engineering
01. Generally the weir is aligned at right angles to the direction of the main river current because
(A) It ensures less length of the weir
(B) It gives better discharging capacity
(C) It is economical
(D) All of the above
Answer: Option D
02. A straight glacis type fall with a baffle platform and a baffle wall is called
(A) Vertical drop-fall
(B) Glacis fall
(C) Montague type fall
(D) Inglis fall
Answer: Option D
03. The meander pattern of a river is developed by
(A) Average discharge
(B) Dominant discharge
(C) Maximum discharge
(D) Critical discharge
Answer: Option B
04. The ratio of the average load to the installed capacity of the plant whose reserve capacity is zero will be equal to
(A) Load factor
(B) Plant factor
(C) Utilisation factor
(D) Both (A) and (B)
Answer: Option D
05. The most suitable chemical which can be applied to the water surface for reducing evaporation is
(A) Methyl alcohol
(B) Ethyl alcohol
(C) Cetyl alcohol
(D) Butyl alcohol
Answer: Option C
06. The shape of recession limb of a hydrograph depends upon
(A) Basin characteristics only
(B) Storm characteristics only
(C) Both (A) and (B)
(D) None of the above
Answer: Option A
07. If the critical shear stress of a channel is XC, then the average value of shear stress required to move the grain on the bank is
(A) 0.5 XC
(B) 0.75 TC
(C) XC
(D) 1.33 TC
Answer: Option B
08. The flow of water after spilling over the weir crest in chute spillway and side channel spillway respectively are
(A) At right angle and parallel to weir crest
(B) Parallel and at right angle to weir crest
(C) Parallel to weir crest in both
(D) At right angle to weir crest in both
Answer: Option A
09. Hydrodynamic pressure due to earthquake acts at a height of
(A) 3H/4π above the base
(B) 3H/4π below the water surface
(C) 4H/3π above the base
(D) 4H/3π below the water surface, where H is the depth of water.
Answer: Option C
10. Select the correct statement.
(A) A meander increases the river length but a cut off reduces the river length
(B) A cut-off increases the river length but a meander reduces the river length
(C) Both meander and cut-off increase the river length
(D) Both meander and cut-off decrease the river length
Answer: Option A
11. Select the incorrect statement.
(A) Intensive irrigation should be avoided in areas susceptible to water logging
(B) Extensive irrigation should be adopted in areas susceptible to water logging
(C) Lift irrigation increases water logging
(D) All of the above
Answer: Option C
12. In India, which of the following is adopted as standard recording rain-gauge?
(A) Symon’s rain-gauge
(B) Tipping bucket type
(C) Natural syphon type
(D) Weighing bucket type
Answer: Option C
13. The flow-mass curve is graphical representation of
(A) Cumulative discharge and time
(B) Discharge and percentage probability of flow being equalled or exceeded
(C) Cumulative discharge, volume and time in chronological order
(D) Discharge and time in chronological order
Answer: Option C
14. Main purpose of mean water training for rivers is
(A) Flood control
(B) To provide sufficient depth of water in navigable channels, during low water periods
(C) To preserve the channel in good shape by efficient disposal of suspended and bed load
(D) All of the above
Answer: Option C
15. A divide wall is provided
(A) At right angle to the axis of weir
(B) Parallel to the axis of weir and upstream of it
(C) Parallel to the axis of weir and downstream of it
(D) At an inclination to the axis of weir
Answer: Option A
16. Isohyets are the imaginary lines joining the points of equal
(A) Pressure
(B) Height
(C) Humidity
(D) Rainfall
Answer: Option D
17. As per Lacey’s theory, the silt factor is
(A) Directly proportional to average particle size
(B) Inversely proportional to average particle size
(C) Directly proportional to square root of average particle size
(D) Not related to average particle size
Answer: Option C
18. The time required by rain water to reach the outlet of drainage basin, is generally called
(A) Time of concentration
(B) Time of overland flow
(C) Concentration time of overland flow
(D) Duration of the rainfall
Answer: Option A
19. Which of the following is a flexible outlet?
(A) Submerged pipe outlet
(B) Kennedy’s gauge outlet
(C) Gibb’s outlet
(D) None of the above
Answer: Option B
20. Pick up the correct statement from the following:
(A) The specified duration of unit hydrograph, is called unit duration
(B) The rain during specified duration, is called unit storm
(C) The number of unit hydrographs for a given basin, is theoretically infinite
(D) All the above
Answer: Option D
21. The drainage water intercepting the canal can be disposed of by passing the canal below the drainage in
(A) Aqueduct and syphon aqueduct
(B) Aqueduct and super passage
(C) Super passage and canal syphon
(D) Level crossing
Answer: Option C
22. River training for depth is achieved by
(A) Groynes
(B) Construction of dykes or leaves
(C) Both (A) and (B)
(D) Groynes and bandalling
Answer: Option D
23. Pick up the correct statement from the following:
(A) A confined bed of impervious material laid over an aquifer, is known as an aquiclude
(B) The top most water bearing strata having no aquifer, is known as non-artesian aquifer
(C) The ordinary gravity wells which supply water from the top most water bearing strata, are called water table wells (D) All the above
Answer: Option D
24. The rate of rainfall for successive 10 minute periods of a 60 minute duration storm, are shown in the below figure. If the value of φindex is 3 cm/hour, the runoff will be
(A) 2 cm
(B) 3 cm
(C) 4 cm
(D) 5 cm
Answer: Option B
25. A land is known as waterlogged
(A) When the permanent wilting point is reached
(B) When gravity drainage has ceased
(C) Capillary fringe reaches the root zone of plants
(D) None of the above
Answer: Option C
26. Boston society of Civil Engineer’s formula Q = 0.0056 × (D/t) in cumecs/square km is based upon
(A) Rainfall and drainage area
(B) Total run off and drainage area
(C) Drainage area and its shape
(D) Drainage area
Answer: Option B
27. A hyetograph is a graphical representation of
(A) Rainfall intensity and time
(B) Rainfall depth and time
(C) Discharge and time
(D) Cumulative rainfall and time
Answer: Option A
28. Pick up the correct statement from the following:
(A) Hydrograph is a plot of discharge and time
(B) In hydrographs, time is plotted on X-axis
(C) The maximum flow in the river due to rainfall, is called peak flow
(D) All the above
Answer: Option D
29. Which of the following methods is used to estimate flood discharge based on high water marks left over in the past?
(A) Slope-area method
(B) Area-velocity method
(C) Moving boat method
(D) Ultrasonic method
Answer: Option A
30. If the dew point is greater than 0°C
(A) Dew will be formed
(B) Frost will be formed
(C) Vapours will be formed
(D) None of these
Answer: Option A
31. For a catchment area of 120 km², the equilibrium discharge in m3/hour of a Scurve obtained by the summation of 6 hour unit hydro graph is
(A) 0.2 × 106
(B) 0.6 × 106
(C) 2.4 × 106
(D) 7.2 × 106
Answer: Option A
32. The specifications of most commonly used standard gauges in India, are
(A) 200 sq. cm collector and 4 litres bottle
(B) 100 sq. cm collector and 2 litres bottle
(C) 200 sq. cm collector and 10 litres bottle
(D) 100 sq. cm collector and 4 litres bottle
Answer: Option A
33. For an annual flood series arranged in descending order of magnitude, the return for a magnitude listed at position period ‘m’ in a total is
(A) N/(m + l)
(B) m/(N + l)
(C) m/N
(D) (N + l)/m
Answer: Option D
34. A control meter is preferred to a weir because
(A) It measures the discharge even in silt Leiden streams
(B) The velocity of approach of the channel increases above the control, and thus removes the silt completely
(C) It is not damaged by floating debris
(D) All the above
Answer: Option D
35. The uplift pressure on the face of a drainage gallery in a dam is taken as
(A) Hydrostatic pressure at toe
(B) Average of hydrostatic pressure at toe and heel
(C) Two-third of hydrostatic pressure at toe plus one-third of hydrostatic pressure at heel
(D) None of the above
Answer: Option C
36. The elevation Z of the watershed is: (where letters carry their usual meanings)
(A) Reduced level of the top most point of the basin
(B) Reduced level of the lower most point of the basin
(C) Average elevation of the highest and lowest point of the drainage basin
(D) Obtained by the formula Z = (a₁z₁ + a₂z₂ + a₃z₃ + anzn)/A
Answer: Option D
37. As compared to gravity dams, earthen dams
(A) Are costlier
(B) Are less susceptible to failure
(C) Require sound rock foundations
(D) Require less skilled labour
Answer: Option D
38. The radius of influence is
(A) Radius of the main well
(B) Distance from the wall of main well to the point of zero draw down
(C) Distance from the centre of main well to the point of zero draw down
(D) None of these
Answer: Option C
39. In case of non-availability of space due to topography, the most suitable spillway is
(A) Straight drop spillway
(B) Shaft spillway
(C) Chute spillway
(D) Ogee spillway
Answer: Option B
40. Dickens’ formula for high flood estimate, is useful only for the catchments in
(A) Southern India
(B) Northern India
(C) Eastern India
(D) Western India
Answer: Option B
41. Silt excluders are constructed on the
(A) River bed upstream of head regulator
(B) River bed downstream of head regulator
(C) Canal bed upstream of head regulator
(D) Canal bed downstream of head regulator
Answer: Option A
42. Pick up the correct statement from the following:
(A) Rivers, lakes, oceans and springs get water from the rains
(B) Rain water is obtained by evaporation from rivers, lakes and oceans
(C) Water remains in atmosphere as vapours
(D) All the above
Answer: Option D
43. For a proportional outlet, the flexibility is
(A) Zero
(B) Between zero and 1
(C) 1
(D) Greater than 1
Answer: Option C
44. Pick up the correct statement from the following:
(A) The portion of pellicular water which remains unutilised, is called hygroscopic water
(B) The moisture content at which permanent wilting of plants takes place, is called the wilting point
(C) The moisture deficiency will be different at different points
(D) All the above
Answer: Option D
45. The aqueduct or super-passage type of works are generally used when
(A) High flood drainage discharge is small
(B) High flood drainage discharge is large and short lived
(C) High flood drainage discharge is large and continues for a long time
(D) None of the above
Answer: Option A
46. If a gauge is installed perpendicular to the slope, its measurement is reduced by multiplying
(A) Sine of the angle of inclination with vertical
(B) Cosine of the angle of inclination with vertical
(C) Tangent of the angle of inclination with vertical
(D) Calibration coefficient of the gauge
Answer: Option B
47. A river training work is generally required when the river is
(A) Aggrading type
(B) Degrading type
(C) Meandering type
(D) Both (A) and (B)
Answer: Option C
48. From the Survey of India map, the distance of the critical point is 20 km and difference in elevation is 193 m. The over land flow time, is
(A) 2 hours
(B) 3 hours
(C) 2 hours and 30 minutes
(D) 4 hours
Answer: Option D
49. The maximum average depth due to one day storm over an area of 100 km² is 100 mm. Depth-Area-Duration (DAD) curves indicate the same area of 100 km² the maximum average depth for a 3 hour storm will be
(A) 100 mm
(B) More than 100 mm
(C) Less than 100 mm
(D) None of the above
Answer: Option B
50. Pick up the correct statement from the following:
(A) Perched aquifer is found in unconfined aquifer
(B) The top surface of the water held in the perched aquifer, is known as perched water table
(C) Perched aquifer is formed in unfined acquirer if an impervious layer exists
(D) All the above
Answer: Option D