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Top 85 Hydraulics and Water Resources Questions and Answers


Hydraulics and Water ResourcesInterview Questions

1. What is fluid mechanics?
The study of fluids (liquids and gases) in motion and at rest is called fluid mechanics.
2. What is hydrology?
Hydrology is the study of the movement, distribution and quality of water on Earth.
3. What is Reynolds number?
Reynolds number is dimensionless number indicating flow type, Re < 2000 is laminar, > 4000 is turbulent.
4. Define specific gravity of a fluid.
Specific gravity of a fluid is the ratio of fluid density to the density of water.
5. What is viscosity?
A fluid’s resistance to deformation or flow is called viscosity.
6. What is absolute pressure?
The total pressure measured from absolute zero, including atmospheric pressure is called absolute pressure.
7. What is gauge pressure?
Pressure measured relative to atmospheric pressure is called gauge pressure.
8. Define surface tension.
Surface tension is the elastic tendency of a fluid surface due to cohesive forces.
9. What is capillarity?
The ability of a liquid to rise or fall in a small tube due to surface tension is called capillarity.
10. What is a manometer?
Manometer is a device used to measure fluid pressure.
11. What is Bernoulli’s theorem?
Bernoulli’s theorem states that the total energy along a streamline remains constant.
12. What are major and minor losses in pipes?
Major losses are due to pipe friction and minor losses occur at fittings and bends etc.
13. What is Darcy-Weisbach equation used for?
Darcy-Weisbach equation is used to calculate head loss due to friction in a pipe.
14. What is the Hazen-Williams formula?
Hazen-Williams formula is an empirical formula used for water flow in pipes.
15. Define hydraulic gradient line (HGL).
A line representing the piezometric head of fluid along the flow is called hydraulic gradient line (HGL).
16. What is total energy line (TEL)?
A line that represents the total energy (pressure, velocity, elevation) at points along the flow is called total energy line (TEL).
17. What is critical flow?
When flow velocity equals the wave velocity is called critical flow.
18. What is the Froude number?
Froude number is a dimensionless number that defines flow regime in open channels.
19. What is subcritical and supercritical flow?
Subcritical (Fr < 1): slow flow; Supercritical (Fr > 1): fast flow.
20. What is a Venturimeter?
A device to measure flow rate in a pipe using pressure difference is called Venturimeter.
21. What is a pump?
A machine that adds energy to fluids to move them from low to high elevation is called pump.
22. What is the difference between centrifugal and reciprocating pumps?
Centrifugal pumps provide continuous flow whereas reciprocating pumps are intermittent.
23. What is Net Positive Suction Head (NPSH)?
The pressure required at the pump suction to avoid cavitation is called Net Positive Suction Head (NPSH).
24. What is cavitation?
The formation of vapor bubbles in a fluid due to low pressure is called cavitation.
25. What is a water turbine?
A device that converts hydraulic energy into mechanical energy is called turbine.
26. Types of water turbines?
Water turbines have two types, Impulse (Pelton) and Reaction (Francis, Kaplan).
27. What is the specific speed of a turbine?
A dimensionless parameter indicating turbine type suitability is called specific speed of a turbine.
28. What is pump efficiency?
The ratio of output power to input power of a pump is called pump efficiency.
29. What is priming in pumps?
Priming in pumps is the process of removing air to fill the pump with fluid before starting.
30. What is a draft tube?
A pipe that recovers pressure energy from turbine discharge is called draft tube.
31. What is the difference between laminar and turbulent flow?
Laminar flow is smooth and orderly, whereas turbulent flow is chaotic and fluctuating.
32. What is a hydrograph?
A graph showing flow rate vs. time at a particular point in a river is called hydrograph.
33. What is infiltration?
Infiltration is the process of water entering the soil from the surface.
34. What is runoff?
Runoff is the water that flows over the ground surface to streams.
35. What is a watershed?
Watershed is an area of land from where water is collected in a lake, river or ocean through runoff is called watershed of that lake, river or ocean.
36. What is evapotranspiration?
Loss of water from soil and plants due to evaporation and transpiration is called evapotranspiration.
37. What is a weir?
A structure to measure or control water flow in open channels is called weir.
38. What is a spillway?
Spillway is a structure to release excess water from a dam.
39. What is the unit hydrograph?
A direct runoff hydrograph resulting from one unit of rainfall excess.
40. What is groundwater recharge?
The process by which water enters the subsurface and refills the aquifers is called ground water recharge.
41. What is irrigation?
Artificial application of water to land for agriculture purposes is call irrigation.
42. What are the types of irrigation systems?
Irrigation can be done by surface, sprinkler, drip and subsurface method.
43. What is duty of water?
Duty of water is the area irrigated per unit of water flow.
44. What is delta in irrigation?
Delta is the depth of water required to grow a crop.
45. What is irrigation efficiency?
Ratio of water used effectively to the total water applied is called irrigation efficiency.
46. What is canal lining?
Canal lining is process of providing impermeable layer on the bottom and sides of canal to prevent seepage losses.
47. What is waterlogging?
Excess water in the soil that affects the crop growth is called waterlogging.
48. What is an aquifer?
A water-bearing geological formation below the earth surface is called aquifer.
49. What is a check dam?
A small barrier to slow water flow and promote groundwater recharge is called check dam.
50. What is conjunctive water use?
Combined use of surface and groundwater for irrigation is called conjunctive water use.
51. What is the primary purpose of water treatment?
Purpose of water treatment is to remove contaminants from water before dispose or reuse.
52. What is coagulation in water treatment?
Coagulation is the process of adding chemicals to water to clump particles together.
53. What is sedimentation?
The process of allowing particles to settle out of the water due to gravity is called sedimentation.
54. What is filtration?
The process of removing suspended solids from water by passing it through filters.
55. What is reverse osmosis?
A water purification process using a semi-permeable membrane to remove ions, molecules and larger particles in the direction opposite to natural osmosis by applying hydrostatic pressure.
56. What is chlorine used for in water treatment?
Chlorine is used to disinfect water by killing harmful microorganisms.
57. What is a water distribution system?
A network of pipes that delivers treated water to homes, industries and institutions is called water distribution system.
58. What is a water treatment plant?
Water treatment plant is a facility that treats water to make it suitable for consumption and distribution.
59. What are the common types of water filters?
Activated carbon, reverse osmosis and UV filters are the common types of water filters.
60. What is hydrological design?
The process of applying hydrology principles to design water systems, including dams, drainage systems and flood protection.
61. What is the Rational Method?
A method for calculating peak runoff from a drainage area based on rainfall intensity, time of concentration and area is called rational method.
62. What is a detention basin?
Detention basin is a temporary storage structure for controlling stormwater runoff.
63. What is a retention pond?
A water body designed to store runoff water permanently and reduce downstream flooding is called retention pond.
64. What is a floodplain?
Floodplain is a flat land area adjacent to a river or stream that may be affected by flooding.
65. What is the SWMM model?
SWMM or Storm Water Management Model is a tool used to simulate the quantity and quality of runoff.
66. What is a catchment area?
An area from which water drains into a specific point, such as a river or reservoir is called catchment area.
67. What is sustainability in water resources?
Managing water resources to meet current needs without compromising future availability is defined as sustainability in water resources.
68. What are low impact development (LID) techniques?
Design strategies that manage stormwater using natural processes to reduce runoff and pollution are called low impact development (LID) techniques.
69. What is an ecological flow?
The minimum flow of water required maintaining a healthy ecosystem in a river or stream is called ecological flow.
70. What is rainwater harvesting?
Collecting and storing rainwater for later use to reduce the dependency on treated water is called rainwater harvesting.
71. What are the effects of deforestation on hydrology?
Deforestation may cause increased runoff, reduced infiltration and heightened flood risks.
72. What is desalination?
The process of removing salt from seawater to make it drinkable is called desalination of water.
73. What is the concept of water footprint?
The total volume of freshwater used for the production of goods and services is called water footprint of that production.
74. What is a dam?
A barrier built across a river or stream to control water flow and store water is called dam.
75. What is the difference between a gravity dam and an arch dam?
Gravity dams rely on their weight to resist water pressure whereas arch dams transfer pressure to the canyon walls.
76. What are the different types of weirs?
Types of weirs includes Sharp-crested, broad-crested and overflow weirs.
77. What is a pipeline cross-section?
A detailed representation of the profile of a pipeline, showing its components and dimensions is called pipeline cross-section.
78. What is a hydraulic jump?
A sudden change in flow velocity and water surface elevation that occurs when high-velocity flow transitions to slower flow is called hydraulic jump.
79. What is energy dissipation in hydraulic systems?
Energy dissipation is the process of reducing the kinetic energy of flowing water to prevent erosion or damage to structures.
80. What is the Navier-Stokes equation?
Navier-Stokes equation is a fundamental equation in fluid mechanics that describes how the velocity field of a fluid evolves.
81. What is a spillway gate?
A movable gate that controls the release of water from a dam or reservoir is called spillway gate.
82. What are flow measurement techniques?
Methods like velocity-area, ultrasonic and electromagnetic sensors used to measure flow in pipes or open channels.
83. What is the velocity profile in open channel flow?
Velocity profile is the distribution of velocity from the bottom to the top of the flow (often parabolic).
84. What is a hydraulic radius?
The ratio of the cross-sectional area of flow to the wetted perimeter in an open channel is called hydraulic radius.
85. What is the Manning's equation used for?
Manning's equation used to estimate the flow rate in open channels based on channel characteristics and roughness.

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