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Practice SetIrrigation Engineering

Irrigation Engineering MCQ Practice Set — 50 Questions with Answers

50 exam-oriented Irrigation Engineering multiple-choice questions with the correct answer and a clear explanation for each. Frequently asked in AE Level Civil Engineering, JE Level Civil Engineering. Solve the full set below for free — no login required.

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  1. 1
    Irrigation EngineeringHARD

    The 'Lacey''s regime theory' for design of stable alluvial canals gives:

    AOnly the canal slope for a given discharge
    BComplete stable channel dimensions (perimeter, hydraulic radius, slope, velocity) from discharge Q and silt factor f
    COnly the canal lining thickness
    DOnly for lined canals

    Answer: B. Complete stable channel dimensions (perimeter, hydraulic radius, slope, velocity) from discharge Q and silt factor f

    Explanation: Lacey''s regime equations (complete): (1) Perimeter P = 4.75√Q; (2) Hydraulic radius R = 0.47(Q/f)^(1/3); (3) Slope S = f^(5/3)/(1840R^(1/6)Q^(1/6)) × ... (simplified: S = f^(5/3)/(3340R^(1/3))); (4) Velocity V = 10.8R^(2/3)S^(1/2). Three equations + continuity (Q=AV) for four unknowns (B, y, V, S) given Q and f. Silt factor f = 1.76√m_r (m_r = mean particle size in mm). Completely replaces Kennedy''s single equation.

  2. 2
    Duty Delta RelationshipMEDIUM

    In irrigation, if the duty D (hectares per cumec) and delta delta (m) over the base period B (days) are related by:

    AD = delta / (8.64 x B)
    BD = 8.64 x B / delta
    CD = B x delta / 8.64
    DD = 8.64 / (B x delta)

    Answer: B. D = 8.64 x B / delta

    Explanation: Fundamental irrigation relation: D = 8.64 x B / delta, where D = duty (ha/cumec), B = base period (days), delta = consumptive delta (m). This ensures Q x T = D x delta x area, giving 1 cumec for B days supplies 8.64B/delta hectares.

  3. 3
    Irrigation EngineeringMEDIUM

    A silty soil of high compressibility is represented by

    AML
    BSM
    CMH
    DCI

    Answer: C. MH

    Explanation: USCS/IS soil classification: M = silt; H = high plasticity/compressibility (LL >= 50%); L = low plasticity (LL < 50%). MH = silty soil of high compressibility (LL >= 50%). Other symbols: CH = high-plasticity clay; CL = low-plasticity clay; ML = low-plasticity silt; OH = high-plasticity organic soil. MH plots below the A-line on Casagrande's plasticity chart. Highly compressible silt is MH.

  4. 4
    Freeboard in DamMEDIUM

    Freeboard in a dam is the vertical distance between:

    ACrest of dam and foundation
    BTop of dam (dam crest) and Maximum Water Level (MWL)
    CMaximum Water Level (MWL) and FRL
    DSpillway crest and dam crest

    Answer: B. Top of dam (dam crest) and Maximum Water Level (MWL)

    Explanation: Freeboard is defined as the vertical distance between the top of the dam (dam crest) and the Maximum Water Level (MWL) reached during the design flood. The original explanation correctly identified this, but the original option B incorrectly listed FRL instead of MWL.

  5. 5
    Crop Water RequirementMEDIUM

    The field irrigation requirement (FIR) for a crop is related to consumptive use (CU), effective rainfall (ER), and soil moisture change (SM) by:

    AFIR = CU - ER - SM
    BFIR = CU + ER + SM
    CFIR = CU x ER / SM
    DFIR = ER - CU + SM

    Answer: A. FIR = CU - ER - SM

    Explanation: Net Irrigation Requirement (NIR) = CU - ER - SM_contribution. FIR is typically equal to NIR when considering field application efficiency. The original option A had a sign error in the explanation/formula.

  6. 6
    Irrigation EngineeringMEDIUM

    In canals likely to be water-logged, the preferable type of irrigation is

    ACanal irrigation
    BFlow irrigation
    CLift irrigation
    DStorage irrigation

    Answer: C. Lift irrigation

    Explanation: Lift irrigation is preferred in areas prone to waterlogging because it allows for more controlled water application, reducing the risk of over-irrigation and subsequent waterlogging.

  7. 7
    Irrigation EngineeringMEDIUM

    A protection work at the downstream end of a weir in form of blocks of concrete or masonry is called

    ATalus
    BBaffles
    CScour
    DFlash boards

    Answer: B. Baffles

    Explanation: Baffle blocks are energy dissipators placed on the downstream apron of a weir to break the flow velocity and reduce turbulence, whereas talus is typically loose stone protection.

  8. 8
    Irrigation EngineeringMEDIUM

    The maximum failures of earthen dams have occurred due to

    AThe erosion caused by burrowing animals
    BThe piping under excessive hydraulic gradient
    COvertopping caused by insufficient spillway capacity
    DSloughing of d/s slope

    Answer: C. Overtopping caused by insufficient spillway capacity

    Explanation: Statistical data on dam failures indicates that overtopping is the most frequent cause of failure for earthen dams, often due to inadequate spillway capacity during extreme flood events.

  9. 9
    Irrigation EngineeringMEDIUM

    A crop that takes more than 4 months to mature is called

    ALong duration crop
    BShort duration crop
    CCash crop
    DPerennial crop

    Answer: A. Long duration crop

    Explanation: Crops are classified based on their duration. Crops that take a longer time (typically more than 4 months) to mature are referred to as long duration crops.

  10. 10
    Irrigation EngineeringMEDIUM

    Consumptive Irrigation Requirement (CIR), if Cu is consumptive use and Re is effective rainfall, is given by

    ACIR = Cu - Re
    BCIR = Cu + 1.5Re
    CCIR = Cu + Re
    DCIR = Cu - Re + water lost as per colation

    Answer: A. CIR = Cu - Re

    Explanation: Consumptive Irrigation Requirement (CIR) is defined as the amount of irrigation water required to meet the consumptive use of the crop, excluding the contribution from effective rainfall. Thus, CIR = Cu - Re.

  11. 11
    Irrigation EngineeringEASY

    The 'evaporation from open water surface' is measured using:

    ARain gauge measurement
    BClass A pan evaporimeter (IS 5973) — open pan with daily water level measurement; multiply by pan coefficient for lake evaporation
    CSoil moisture sensors only
    DStream gauging station

    Answer: B. Class A pan evaporimeter (IS 5973) — open pan with daily water level measurement; multiply by pan coefficient for lake evaporation

    Explanation: Evaporation measurement: (1) Class A pan evaporimeter (IS 5973): standard 1.21 m dia × 0.25 m deep floating or land pan; (2) Colorado sunken pan; (3) ISI pan (India). Pan evaporation × pan coefficient (Kp ≈ 0.7–0.8) = lake evaporation. Pan coefficient accounts for pan overheating. India: annual pan evaporation = 150–200 cm in arid areas.

  12. 12
    Irrigation EngineeringMEDIUM

    In sprinkler irrigation, the 'application rate' should be:

    AAlways 100 mm/hour regardless of soil type
    BNot exceed the soil''s infiltration rate to prevent runoff — matched to soil permeability
    CAs high as possible for speed
    DZero mm/hour (sprinklers do not apply water to soil)

    Answer: B. Not exceed the soil''s infiltration rate to prevent runoff — matched to soil permeability

    Explanation: Application rate of sprinkler system must be ≤ infiltration rate of soil. If application rate > infiltration rate → surface runoff and ponding (defeating purpose). Application rate depends on: nozzle size, pressure, and sprinkler spacing. Design: application rate 5–15 mm/hour for typical soils; adjust for clay (low k) and coarse sand (high k).

  13. 13
    Irrigation EngineeringMEDIUM

    The 'command area' of a tank depends on:

    AOnly the tank surface area
    BTank capacity (available water), sluice location (command height), crop demand, and topography below the sluice
    COnly depth of water in tank
    DNumber of irrigation channels

    Answer: B. Tank capacity (available water), sluice location (command height), crop demand, and topography below the sluice

    Explanation: Tank command area: governed by: (1) Sluice location and height (determines area that can be gravity-irrigated); (2) Tank capacity (total water available = storage); (3) Crop water requirement and season; (4) Rainfall in catchment. Command area = f(storage, release, and topography below sluice). Ayacut = net irrigated command area. Ayacut/catchment ratio: 1:25 to 1:50 for peninsular tanks.

  14. 14
    Irrigation EngineeringEASY

    'Tank irrigation' predominates in which region of India?

    ANorth-West India (Punjab, Haryana) — canal irrigation dominant there
    BPeninsular India — Tamil Nadu, Andhra Pradesh, Telangana, Karnataka where rocky terrain and seasonal rivers favour tank storage
    CHimalayan foothills only
    DCoastal Andaman & Nicobar Islands

    Answer: B. Peninsular India — Tamil Nadu, Andhra Pradesh, Telangana, Karnataka where rocky terrain and seasonal rivers favour tank storage

    Explanation: Tank irrigation: major in peninsular India — Tamil Nadu, Andhra Pradesh/Telangana, Karnataka, Odisha, Maharashtra (Marathwada). Tanks (ponds/reservoirs) formed by earthen bunds across streams; water stored for kharif and rabi. Tamil Nadu has over 40,000 tanks (Eris). Karnataka: Kolar tanks. AP/Telangana: large cascades. Less rainfall, hard rock terrain makes canal irrigation difficult → tanks preferred.

  15. 15
    Irrigation EngineeringEASY

    The 'free board' in an irrigation canal is provided to:

    AIncrease canal discharge capacity
    BSafety margin above FSL for waves, floods, uncertainty — prevents overtopping of canal banks
    CAllow fish to jump out of canal
    DReduce seepage losses

    Answer: B. Safety margin above FSL for waves, floods, uncertainty — prevents overtopping of canal banks

    Explanation: Freeboard: vertical distance between the Full Supply Level (FSL) and top of bank. Provided for: (1) Wave action in wind; (2) Measurement uncertainty; (3) Excess inflow during floods; (4) Unexpected blockages downstream raising level. Typical freeboard: 0.5–1.0 m for large canals; 0.3–0.5 m for small channels. IS 7112 recommends freeboard based on discharge.

  16. 16
    Irrigation EngineeringHARD

    The 'Kennedy''s silt theory' for canal design states that:

    ASilt factor depends on grain size of material
    BCritical (non-silting, non-scouring) velocity V0 = 0.55m×y^0.64 where m = silt factor, y = depth of flow
    CSilt settles whenever velocity exceeds 0.55 m/s
    DCanal must flow at full supply depth always

    Answer: B. Critical (non-silting, non-scouring) velocity V0 = 0.55m×y^0.64 where m = silt factor, y = depth of flow

    Explanation: Kennedy (1895, from Upper Bari Doab Canal): critical velocity V0 = 0.55 m × y^0.64 where m = channel-soil factor (1.0 for standard, varies 0.7–1.2), y = depth of flow. When actual V = V0: neither silt deposited nor scoured. Limitation: only one variable (depth) but two unknowns (B, y). Kutter''s formula for n and S also needed. Improved by Lacey''s regime theory which adds all cross-section variables.

  17. 17
    Hydrology and Irrigation EngineeringEASY

    A diversion headwork is constructed to:

    AGenerate tidal power only
    BRaise water level and divert river water into canal
    CCarry road traffic only
    DStore water for many years only

    Answer: B. Raise water level and divert river water into canal

    Explanation: Headworks provide ponding and controlled entry into canals.

  18. 18
    Canal FallsMEDIUM

    Which of the following about lowering canal bed level safely in civil engineering is correct?

    Afalls eliminate flow velocity
    Bfalls are used to increase command level indefinitely
    Cfalls are only for navigation locks
    Dfalls dissipate excess energy when canal bed drops

    Answer: D. falls dissipate excess energy when canal bed drops

    Explanation: Canal falls manage bed slope and energy dissipation. Correct option: D.

  19. 19
    Discharge Measurement WeirMEDIUM

    For a broad-crested weir, the maximum discharge per unit width occurs when the depth of flow over the crest y_c satisfies:

    Ay_c = H (full upstream head)
    By_c = 2H/3 (two-thirds of upstream head = critical depth on crest)
    Cy_c = H/2
    Dy_c = H/4

    Answer: B. y_c = 2H/3 (two-thirds of upstream head = critical depth on crest)

    Explanation: For a broad-crested weir (critical flow on the crest): y_c = 2H/3, where H = upstream head above crest. Maximum q = (2g/3)^(1/2) x (2H/3)^(3/2) = 1.705 H^(3/2) per unit width (ideal). This is the critical flow condition on the horizontal crest.

  20. 20
    TubewellsMEDIUM

    The specific capacity of a tube well is defined as:

    ATotal yield divided by pumping hours
    BDischarge per unit drawdown (L/s per m of drawdown)
    CMaximum possible yield
    DWell diameter in metres

    Answer: B. Discharge per unit drawdown (L/s per m of drawdown)

    Explanation: Specific capacity = Q/s = discharge (L/s or m3/h) / drawdown (m). Higher specific capacity indicates a more productive well. It varies with pumping rate and time. Used to estimate aquifer transmissivity and compare wells.

  21. 21
    Irrigation Canal SectionsMEDIUM

    A trapezoidal canal section in alluvial soil with side slopes z:1 (H:V) and designed by Lacey theory generally has side slopes of:

    A1:1 (45 degrees)
    B0.5:1 (steep)
    C1.5:1 (for cohesive soils up to 2:1 for sandy soils)
    D3:1 for all types

    Answer: C. 1.5:1 (for cohesive soils up to 2:1 for sandy soils)

    Explanation: Side slopes depend on soil: Sandy loose soil: 2:1 to 3:1 (H:V); loamy soil: 1.5:1; stiff clay: 1:1; hard material: 0.5:1 to 0:1. Lacey theory does not fix side slopes; these are chosen based on soil stability and Kennedy/Lacey velocity then checked.

  22. 22
    Dam SafetyMEDIUM

    The factor of safety against overturning of a gravity dam is checked by ensuring that:

    AThe resultant of all forces passes through the centre of the base
    BThe resultant of all forces falls within the middle third of the base (eccentricity e <= B/6)
    CThe dam height does not exceed 100 m
    DUplift is completely neglected

    Answer: B. The resultant of all forces falls within the middle third of the base (eccentricity e <= B/6)

    Explanation: For gravity dam stability: (1) No tension: resultant within middle third (e <= B/6) for tension-free base; (2) No overturning: sum of resisting moments > sum of overturning moments; (3) No sliding: sum of horizontal forces / sum of vertical forces < permissible friction coefficient.

  23. 23
    Scour Depth LaceyMEDIUM

    Lacey formula for scour depth (R) at a bridge/weir site in alluvial soil in terms of design discharge per unit width q and silt factor f is:

    AR = 1.35 (q^2/f)^(1/3)
    BR = 0.47 (Q/f)^(1/3)
    CR = q / (0.47 f)
    DR = 4.75 sqrt(q/f)

    Answer: A. R = 1.35 (q^2/f)^(1/3)

    Explanation: Lacey scour depth: R = 1.35 (q^2/f)^(1/3), where q = discharge per unit width (cumec/m), f = Lacey silt factor. Used at bridge and weir sites to determine the maximum depth of scour below HFL for safe foundation depth.

  24. 24
    Spillway Design FloodMEDIUM

    The design flood used for spillway capacity of a major dam is generally:

    AMean annual flood
    B50-year return period flood
    CStandard Project Flood (SPF) or Probable Maximum Flood (PMF) based on dam hazard potential
    D10-year return period flood

    Answer: C. Standard Project Flood (SPF) or Probable Maximum Flood (PMF) based on dam hazard potential

    Explanation: IS 11223 and CWC guidelines: Spillway design flood for small dams (low hazard) = 100-year flood; medium dams = SPF (Standard Project Flood, approximately 40-50% of PMF); large dams/high hazard = PMF (Probable Maximum Flood). PMF uses the Probable Maximum Precipitation (PMP).

  25. 25
    Unit Hydrograph AssumptionsMEDIUM

    The unit hydrograph theory assumes:

    AVariable base time for different storm durations
    BTime invariance and linearity: direct runoff hydrograph for same unit storm in same basin is always the same (time-invariant), and responses can be superposed
    CRunoff is always equal to rainfall
    DThe hydrograph peak is always at t = tp = 0

    Answer: B. Time invariance and linearity: direct runoff hydrograph for same unit storm in same basin is always the same (time-invariant), and responses can be superposed

    Explanation: Unit hydrograph (Sherman, 1932) assumptions: (1) Time invariance - unit hydrograph for a given basin is constant regardless of when unit storm occurs; (2) Linear superposition - response to multiple unit storms can be superposed; (3) Unit duration rainfall.

  26. 26
    Canal Distributary SystemMEDIUM

    In an irrigation canal network, the correct hierarchy from main canal to field channel is:

    AMain canal -> Branch canal -> Distributary -> Minor -> Watercourse
    BDistributary -> Branch -> Main -> Minor
    CMain canal -> Watercourse -> Branch -> Minor
    DBranch canal -> Main canal -> Distributary -> Minor

    Answer: A. Main canal -> Branch canal -> Distributary -> Minor -> Watercourse

    Explanation: Canal hierarchy: Main canal (off-taking from barrage/dam) -> Branch canals (major off-takes) -> Distributary canals -> Minor canals -> Field channels (watercourses) -> Field application. Outlets (moghas) connect distributaries/minors to watercourses.

  27. 27
    Irrigation EfficiencyMEDIUM

    The field application efficiency is the ratio of:

    AWater delivered to field / water released at canal head
    BWater stored in root zone / water applied to the field
    CWater applied to field / water stored in reservoir
    DWater consumed by crop / rainfall

    Answer: B. Water stored in root zone / water applied to the field

    Explanation: Field application efficiency (Ea) = water stored in root zone / water applied at field. Typically 60-80%. Overall project efficiency = Ea x Water conveyance efficiency x Water distribution efficiency. Low efficiency leads to waterlogging and wastage.

  28. 28
    Garret DiagramsMEDIUM

    Garret diagrams (Garret tables for irrigation design) are used to determine:

    ACanal discharge from rainfall data
    BTrapezoidal section dimensions for canals designed on Kennedy theory
    CTube well yield
    DCrop water requirements

    Answer: B. Trapezoidal section dimensions for canals designed on Kennedy theory

    Explanation: Garret diagrams / tables give trapezoidal canal section dimensions (top width, bottom width, depth, side slopes, velocity) designed using Kennedy theory and Manning equation, for given discharge and silt factor. They save iterative design calculations.

  29. 29
    Reservoir Trap EfficiencyMEDIUM

    The trap efficiency of a reservoir (as per Brune curve) depends primarily on:

    AAnnual inflow / reservoir capacity ratio (capacity-inflow ratio)
    BReservoir depth
    CDam height
    DSpillway capacity

    Answer: A. Annual inflow / reservoir capacity ratio (capacity-inflow ratio)

    Explanation: Brune (1953) trap efficiency curve: TE (%) vs capacity-inflow (C/I) ratio. High C/I (large storage) = high trap efficiency (approaches 100%); low C/I (small/run-of-river) = low TE. This determines the rate of siltation and useful life of a reservoir.

  30. 30
    Regime ChannelsHARD

    According to Lacey's regime theory, the hydraulic mean radius R of a stable alluvial channel is related to the discharge Q as:

    AR ∝ Q^(1/6)
    BR ∝ Q^(1/3)
    CR ∝ Q^(1/2)
    DR ∝ Q^(2/3)

    Answer: B. R ∝ Q^(1/3)

    Explanation: Lacey's regime formula: R = 0.47 (Q/f)^(1/3), where f is Lacey's silt factor. Thus R ∝ Q^(1/3). Velocity V ∝ Q^(1/6) and area A ∝ Q^(5/6) in Lacey's regime, which differ from Kennedy's approach.

  31. 31
    Irrigation Engineering and HydrologyHARD

    The relation between duty D, base period B days and delta Delta metres is:

    ADelta=DB/864
    BDelta=8.64B/D
    CD=Delta/(8.64B)
    DB=8.64D/Delta

    Answer: B. Delta=8.64B/D

    Explanation: Using 1 cumec-day over 1 hectare = 8.64 cm gives Delta = 8.64B/D in metres when D is ha/cumec.

  32. 32
    Irrigation Engineering and HydrologyHARD

    Duty of water is expressed as:

    Ametres per second
    Bcumec per hectare
    Chectares per cumec
    Dkilonewtons per metre

    Answer: C. hectares per cumec

    Explanation: Duty is area irrigated by a unit discharge during crop base period.

  33. 33
    Hydrology and Irrigation EngineeringHARD

    Annual irrigation intensity may exceed 100 percent because:

    ACanal water flows upward
    BGross area becomes negative
    CSame land may be irrigated in more than one crop season
    DDuty is always zero

    Answer: C. Same land may be irrigated in more than one crop season

    Explanation: Multiple cropping counts irrigated area separately for each season.

  34. 34
    Hydrology and Irrigation EngineeringEASY

    Lacey's silt factor depends mainly on:

    AMean particle size of bed material
    BCanal length only
    CRainfall intensity only
    DCrop type

    Answer: A. Mean particle size of bed material

    Explanation: Silt factor represents sediment grade and is related to particle size.

  35. 35
    Hydrology and Irrigation EngineeringEASY

    A superpassage is a work where:

    ARiver is fully blocked
    BCanal passes over drainage
    CCanal is siphoned under road
    DDrainage passes over canal

    Answer: D. Drainage passes over canal

    Explanation: Superpassage carries drain water above the canal.

  36. 36
    Irrigation EngineeringMEDIUM

    A canal designed for 1200 hectares of rice, base period 140 days and delta 134 cm, is used for wheat of base period 120 days and delta 52 cm. The area irrigated is

    A2650 ha
    B3608 ha
    C543 ha
    D2000 ha

    Answer: A. 2650 ha

    Explanation: For same discharge, area is proportional to duty B/delta. New area = 1200 x (120/0.52)/(140/1.34) ≈ 2650 ha

  37. 37
    Irrigation EngineeringMEDIUM

    The intensity of irrigation means

    Apercentage of culturable commanded area to be irrigated annually
    Bpercentage of gross commanded area to be irrigated annually
    Cpercentage of the mean of CCA and GCA to be irrigated annually
    Dtotal depth of water supplied divided by number of waterings

    Answer: A. percentage of culturable commanded area to be irrigated annually

    Explanation: Intensity of irrigation is the percentage of CCA proposed/actually irrigated in a year/season

  38. 38
    Irrigation EngineeringMEDIUM

    When a river starts meandering, the sediment carrying capacity:

    Afirst decreases and ultimately increases
    Bfirst increases and ultimately decreases
    Cremains unaffected
    Dchanges erratically

    Answer: A. first decreases and ultimately increases

    Explanation: Meandering initially reduces slope and velocity, but later curvature and secondary flows may increase local sediment carrying/erosion capacity

  39. 39
    Irrigation EngineeringMEDIUM

    In a gravity dam, total force due to wave pressure hw above still water acts at a height of:

    A0.375 hw
    B0.50 hw
    C0.92 hw
    D0.66 hw

    Answer: A. 0.375 hw

    Explanation: Resultant wave pressure is taken to act at about 3/8 of wave height above still water level

  40. 40
    Irrigation EngineeringMEDIUM

    Dead storage in a reservoir is provided

    Ato meet emergency needs
    Bto mitigate floods
    Cto accommodate the silt trapped in the reservoir
    Dto provide drinking water during lean season

    Answer: C. to accommodate the silt trapped in the reservoir

    Explanation: Dead storage is reserved below outlet level mainly for sediment deposition and unavailable storage

  41. 41
    Irrigation EngineeringMEDIUM

    The axis of a groyne with respect to the river flow direction generally makes

    Aan acute angle
    Ban obtuse angle
    Ca right angle
    Dan angle of 80°

    Answer: A. an acute angle

    Explanation: A groyne is commonly set at an angle to the flow; attracting/repelling types use acute downstream/upstream orientation

  42. 42
    Irrigation EngineeringMEDIUM

    The canal has to irrigate 12000 ha of rice with duty 1000 ha/cumec. Capacity factor is 0.8 and time factor 0.75. Required discharge is

    A96 m³/s
    B9 m³/s
    C20 m³/s
    D12.8 m³/s

    Answer: C. 20 m³/s

    Explanation: Q = area/(duty × capacity factor × time factor)=12000/(1000×0.8×0.75)=20 m³/s

  43. 43
    Irrigation EngineeringMEDIUM

    Guide banks are provided

    Ato guide the flow of river along a specified course
    Bto confine the width of the river
    Cto reduce the flood peak
    Dnone of the above

    Answer: A. to guide the flow of river along a specified course

    Explanation: Guide banks train the river flow safely through a bridge or barrage waterway

  44. 44
    Irrigation EngineeringMEDIUM

    Removal of soluble salts by downward movement of water through the soil is called

    ASedimentation
    BLeaching
    CDraining
    DWashing

    Answer: B. Leaching

    Explanation: Leaching removes salts by percolating water through soil

  45. 45
    Irrigation EngineeringMEDIUM

    A diversion head work is constructed to

    AFacilitate the silt entry into the canal
    BLower water level in the river
    CRegulate the intake of water into the canal
    DCheck the erosion of river bed

    Answer: C. Regulate the intake of water into the canal

    Explanation: A diversion headwork raises and controls river water for canal off-take

  46. 46
    Irrigation EngineeringMEDIUM

    The best dam type for resisting earthquake shocks is

    Aearth dams
    Brock-fill dams
    Csolid masonry gravity dams
    Dhollow masonry gravity dams

    Answer: A. earth dams

    Explanation: Earth dams are relatively flexible and perform well under seismic shaking

  47. 47
    Irrigation EngineeringMEDIUM

    Fluming of canal in cross-drainage works means

    Acontracting the waterway of canal
    Bwidening the canal
    Craising canal bed
    Dproviding drain under canal

    Answer: A. contracting the waterway of canal

    Explanation: Fluming reduces/contract the canal section at a structure

  48. 48
    Irrigation EngineeringMEDIUM

    Duty 864 hectares/cumec and base period 120 days give delta

    A30 cm
    B60 cm
    C90 cm
    D120 cm

    Answer: D. 120 cm

    Explanation: Delta = 8.64B/D = 8.64x120/864 = 1.2 m = 120 cm

  49. 49
    Irrigation EngineeringMEDIUM

    In a chute spillway, flow is usually

    Auniform
    Bsubcritical
    Ccritical
    Dsupercritical

    Answer: D. supercritical

    Explanation: Chute spillway flow is normally supercritical.

  50. 50
    Irrigation EngineeringMEDIUM

    The total depth of water required by a crop during the entire period the crop is in the field is known as

    ADelta
    BDuty
    CBase period
    DCrop period

    Answer: A. Delta

    Explanation: Delta is total depth of water required by a crop over its base period.

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