WBPSC AE 1998 (Irrigation) question paper with answers

Q1.If the irrigation water requirement of a crop of base period 150 days is 100 cm. than the flow duty in ha/cumee is

1. 648
2. 864
3. 1296
4. 12.96

Q2.Water is relased at the head of a canal at the rate of 10 qumees. It irrigates an area of 10,000 ha. If the duty at the field is 12.50 ha/cumee the loss of water in transit is

1. 12.5%
2. 20%
3. 25%
4. 22.5%

Q3.Consumptive use, in magnititude, is

1. equal to evapotranspiration
2. more than evapotranspiration
3. less than evapotranspiration
4. usually taken as 1.1 times evapotranspiration

Q4.In an orchard of mango trees, the most suitable method of irrigation is

1. Drip
2. Basin flooding
3. Sprinkler
4. Furrow

Q5.Water requirement of wheat is

1. equal to that of paddy
2. greater than that of paddy
3. twice that of paddy
4. Less than that of paddy

Q6.Drip irrigation is useful in

1. marshy areas
2. flood plain areas
3. hilly areas
4. aird or semi-arid areas

Q7.The purpose of mixed cropping is-

1. to increase fertility of land
2. to minimize chances of waterlogging
3. to assure some yield from field
4. to increase income from the field

Q8.For irregular topography the most suitable method of irrigation will be-

1. wild flooding
2. Sprinkler irrigation
3. Drip irrigation
4. readily-available mositure

Q9.Blancy-Criddle formula is used to computer

1. monthly consumptive use
2. annual evaporranspiration
3. open water evaporation
4. readily avaible moisture

Q10.Evaporation from a class A pan is 0.5 cm/day. Evaporation per month from a canal, 100 kg lond and average surface of 15 m will be

1. 15700 m³
2. 225000 m³
3. 321428 m³
4. 11250 m³

Q11.In irrigation water supply

1. delta increases if duty increases
2. delta decreases if duty increases
3. duty is independent of delta
4. duty and delta are always equal

Q12.Conveyance efficiency is the ratio of water supplied at equal head to that

1. consumed by plants
2. obtained at outlet
3. stored in root zone
4. lost in seepage

Q13.Hyetograph is a plot of

1. rainfall depth versus time
2. rainfall intensity versus time
3. run-off depth versus time
4. discharge versus time

Q14.When rainfall is associated with considerable amount of snow the most suitable type of raingauge is

1. Tippingbucket
2. Float
3. Symon's raingauge
4. Weighing bucket

Q15.Instantaneous intensities during a rainstrom can be computed from-

1. Hyetograph
2. Isohyetal map
3. Double mass curve
4. Mass curve of rainfall

Q16.The maximum rate at which a given soil, at a given time, can absorb water is defined as

1. Infiltration rate
2. Infiltration capacity
3. O-index
4. W-index

Q17.For small turbulent streams the most suitable method of determining stream discharge is

1. area velocity
2. dilution
3. slope area
4. moving boat

Q18.The 6-hr unit hydrograph of a catchment is traingular in shape. The peak discharge is 40 cumees and the time base is 75 hours. the catchment area is

1. 360 sq. km
2. 450 sq. km
3. 540 sq. km
4. 630 sq. km

Q19.The peak value of the 2 hr. unit hydrograph of a medium catchment as compared to a 1-hr. unit hydrograph of the same catchment is

1. twice
2. half
3. equal
4. a fraction more than half

Q20.For estimating peak discharge the formula Q=C.A^(2/3) is given by

1. Dickens
2. Ryve
3. Inglis
4. Fuller

Q21.The process by which rain water enters the surface of earth is called

1. Percolation
2. Infiltration
3. Seepage
4. Absorption

Q22.Line on a map joining points from which time of travel of water to reach coutlet point of a basin is equal is called

1. Isobar
2. Isohyet
3. Isovel
4. Isochrone

Q23.For a river section obser flood hydrograph peak is 1000 cumees, the base flow of the river is 200 cumes DRH peak will be-

1. 800 cumees
2. 200,000 cumees
3. 1200 cumes
4. 980 cumees

Q24.Lacey's scour depth 'R' in metre is related to 'q' cumees/meter and 'f' as-

1. 1.35(q²/f)^(1/3)
2. 1.35(q/f)^(1/3)
3. 1.0(q²/f)^(1/3)
4. 1.2(q/f)^(1/3)

Q25.Modified Penman Equation is used for the estimation of

1. avrage annual rainfall
2. evapotranspiration
3. effective rainfall
4. ran-off from a basin

Q26.Rainfall simulators are used to determine

1. average rainfall depth
2. infiltration capacity
3. rainfall potential of a strom
4. rainfall intensify

Q27.A unit hydrograph refers to one unit of

1. Peak discharge
2. Rainfall intensity
3. Rainfall excess
4. Time base

Q28.Sugarcane is a

1. Kharif crop
2. Rabi crop
3. Boro crop
4. Annual crop

Q29.For same amount of rainfall and equal catchement area, run-off will be highest:

1. in a village
2. in a metropolis
3. in a forest
4. in a desert

Q30.The annual yeild of a section of a stream can best be assesed by-

1. Dickens formula
2. Steam gauging
3. Unit hydrograph method
4. Comparison with neighbouring stream

Q31.Current meters are used for measuring

1. discharge of stream section
2. depth of stream section
3. area of stream section
4. velocity of stream section

Q32.Staff gauges are used for mesuring

1. river bed elevation
2. water surface elevation
3. Pressure of liquid
4. relative humidity

Q33.When the F.S.L. of the canal lies between the bed level and H.F.L. of the drain the cross-drianage work provided is

1. an aqueduct
2. a syphon aqueduct
3. a super passage
4. a syphon superpassage

Q34.Lacey's equation can be used for canals which are in

1. true regime
2. permanent regime
3. initial regime
4. final regime

Q35.The stable waterway required for a river in alluvial plain carrying a discharge of 1600 cumees is

1. 160 m
2. 190 m
3. 210 m
4. 240 m

Q36.Contour canals usually

1. need no canal fall structures
2. need no cross-draingage works
3. runs almost parallel to natural drainages
4. can irrigate both sides of it

Q37.In a canal network system for irrigation, the main canal

1. supplies water to most of the field directly
2. supplies water to the fields for major crops
3. supplies water to the most important areas
4. usually does not supply irrigation water directly

Q38.Silt excludes are provided

1. near the canal head regulator
2. at the lowest protion of the dam
3. near the afflux buch
4. below the spilway

Q39.When a canal pass above a river with canal bed level above river H.F.L it is called

1. Supper passage
2. Aqueduct
3. Syphon aqueduct
4. Level crossing

Q40.A balanced canal section is preferred, because it

1. is most stable
2. is economical
3. increases carrying capacity
4. reduces seepage

Q41.Number of cross drainage structures will be the least if the canal is constructed

1. along a ridge
2. along contour
3. across contours
4. along a valley

Q42.Canal falls are provided when the agailable ground slope is

1. Flatter than the design bed slope of the canal
2. Flatter than the side slope of the canal
3. Steeper than the design bed slope of the canal
4. Steeper than the side slope of the canal

Q43.Stilling basin is provided at the downstream floor of a regulatior to

1. increase the discharge through the regulator
2. trap silt in the downstream floor
3. 'reduce uplit pressure on the floor
4. dissipate energy of flow

Q44.Waterway (P) suggested in desion or bridge is

1. 4.75√Q
2. 2.67√Q
3. 1.76√Q
4. 3.33√Q

Q45.In design of earthen channel the most commonly used value for roughness coefficient may be taken as

1. 0.25
2. 0.14
3. 0.014
4. 0.0225

Q46.The hydraulic mean radius of a lined canal, of traingular cross-section with usual rounded bottom, having depth of flow D and sides sloping to θ with horizontal is

1. D/2
2. (D/2)cotθ
3. D
4. D cotθ

Q47.The flow net under a hydraulic structure has 5 flow channel with 10 equipotential drops. If the permeability of the bed material is 1.5×10⁻⁴ m/sec, the quantity of seepage per meter width of the structure in m²/sec. under 3m head is

1. 2.25×10⁻⁴
2. 4.50×10⁻⁴
3. 6.75×10⁻⁴
4. 9.00×10⁻⁴

Q48.In a diversion headwork if the major part of entire ponding of water is achieved by a permanent raised crest, then it is know as

1. River regulator
2. Barrage
3. Weir
4. Diversion dam

Q49.The crest level of the underslutice bays are kept at

1. lacey's scour depth for non-monsoon flow
2. Average bed level of the river
3. Deepest bed level of river for non-monsoon flow
4. lowest water level during non-monsoon flow

Q50.In a barrage installed in the alluvial reach of the river, the scour depth likely to occur at downstream of impervious floor is

1. 2×Lacey's scour depth
2. 1.5×Lacey's scour depth
3. 1.75×Lacey's scour depth
4. Lacey's scour depth

Q51.A barrage

1. is only a pick up weit
2. raises the upstream water level in the river
3. has no gate-controlled spillway
4. does not have any undersluice

Q52.A long continuous vertical wall, having negligible thickness and embeded into the ground up to a depth d, retains water on one side up a to a height H above the ground. The exit gradient is

1. H/d
2. H(πd)
3. H/d
4. √(H/d/π)

Q53.For weirs and barrages on permeable foundation, caritical exit gradiett

1. depends length of floor and sum of depth of sheet piles
2. depends on porosity of soul
3. depends on depth of upstream and downstream sheet
4. in independent of specific gravity of soil grains

Q54.A barrage on permeable doundation has 5.6 m height of stores water. Creep length of the structure according to Blight's theory is 60 m. Specific gravity of the floor material is 2.4. Thickness of floor at D/S of the barrage at a point where creep length is 30m, is

1. 3.13 m
2. 2.67 m
3. 2.12 m
4. 1.33 m

Q55.In diversion headworks, located in the boulder stage, as compared to those located in the troughst age

1. subsoil flow is less
2. idle length of canal is less
3. Length of the weir proper is less
4. river training works required is more

Q56.Due to seepage flow, a barrage may fail by

1. piping
2. scour
3. suction
4. launching

Q57.In a barrage with a horizontal floor length of 40 m and a 10m deep downstream cut-off the exit gradient for a seepage head of 6m, assuming constant rate of loss is

1. 0.75
2. 0.10
3. 0.12
4. 0.15

Q58.The percentage pressures (expressed as percentage of total head) before correction for floor thickness, at the inside corner and bottom of the downstream pile are 48% and 32% respectively. The R.L.S of the two points are 152.0 m and 142.0 m. If the thickness of the floor is 1.3 m, the corrected pressure at the inside corner is (as percentage of total head)

1. 60.80%
2. 45.92%
3. 50.39%
4. 45.61%

Q59.Bed load of the river is denied entry into the canal by constructing-

1. a silt ejector
2. a silt excluder
3. cantilever skimming platform
4. Gibb's Groyne wall

Q60.Exist gradient is

1. gradient of the piezometric head at exit point of a streamline
2. gradient of the steream function at exit point of a streamline
3. gradient of a streamline at exit point
4. equal to the submerged weight of unit value of soil

Q61.In Bligh's creep theory

1. Providing a cut-off at the downstram end of the floor is absolutely necessary to prevent piping
2. Head loss is proportional to the square of the creep length
3. No distinction is made netween horizontal and vertical creep
4. The uplift pressure distribution is parabolic

Q62.Immediately after the construction on a barrage, the downstream reach of the soil is 2.66. The porosity of the soil is

1. 0.2
2. 0.25
3. 0.30
4. 0.40

Q63.The safe exist gradient with a factor of safety 4 is 0.15. The relative density of the soil is 2.66. The porosity of the soil is

1. 0.2
2. 0.25
3. 0.30
4. 0.40

Q64.The type of dam suitable for construction in a narrow V shaped gorge having sound, competent rock on side slopes is

1. Gravity dam
2. Arch dam
3. Buttress dam
4. Earth dam

Q65.A dam primarity constructed to reduce flood peaks by inpoinding the flood flow in excess of capacity of downstream channel is known as

1. Diversion dam
2. storage dam
3. Diversin-cum-storage dam
4. Detention dam

Q66.Stability enalysis for the downstream slope of an earth dam is essentially carried out for

1. full reservoir condition
2. Partial filling condition
3. sudden drawdown condition
4. construction condition

Q67.In a zoned rolled earthfill dam the central core zone serves the purpose of

1. checking seepage loss from reservoir
2. allowing passage of water through it
3. allowing water to pass through it and retain fine materials
4. providing stability against sudden drawdown

Q68.Rock toe is provided

1. in a rockfill dam
2. in an earth embankment dam
3. in an arch dam
4. in a buttress dam

Q69.Uplift force when acting on a gravity dam, increases the factor of safety against

1. overturning
2. sliding
3. crushing
4. tension

Q70.If the design flood is under estimated an earth dam may fail due to

1. erosion fo upstream face
2. piping through dam body
3. Slide in embankment
4. overtopping of the dam

Q71.The phreatic line of an earth dam is considered as

1. an equipotential line
2. a streemline
3. neither a stram line nor an equipotentional line
4. sometimes a streamline and sometimes as equipotential line

Q72.The line within a dam embankment below which there exists positive hydrostatic pressure is termed as

1. hydroulic gadient line
2. exit gradient line
3. phreatic line
4. atmospheric pressure line

Q73.The wave height on the upstream face of a dam depends on

1. wind velocity and fetch
2. fetch and depth of water in the reservoir
3. depth of water in the reservoir and free board
4. free board and wind velocity

Q74.For stability of the upstream slope of an earth dam the most critical condition is

1. sudden dradown
2. steady seepage with upstream blanket
3. steady seepage without upstream blanket
4. during construction when the reservoir is allowed to be filled

Q75.In the seepage flow through a porous foundation or body of a dam, piping is

1. used to measure the uplift pressure
2. undertaken beneath the floor for its protection
3. due to dislodging of soil grains by percolating water
4. a method for determination of exit velocity

Q76.The maximum height of a low dam is given by

1. H = F/(W√(S-C+1))
2. H = F/(W(S-C))
3. H = f/(W√(S-C))
4. H = f/(W(S-C+1))

Q77.To prevent sloughting, the an earth dam it is necessary to provide

1. rip-rap
2. impervious brenket
3. rock-toe
4. relief wells

Q78.In the practical profile of a low gravity dam, the base width of the elementary profits is used

1. unaltered
2. with some extension on the upstream side
3. with some extension on the downstream side
4. with extensions on both upstream and downstream sides

Q79.River training work primarily to protect river bank is

1. P
2. bandalling
3. marginal embankment
4. groyne

Q80.A guide bank is primarily provided to

1. prevent out flanking
2. maintain deep channel
3. protect river banks
4. dispose bed and sediment loads effectively

Q81.A groyre pointing upstream protects the river

1. upstream of the groyne from siltingup
2. upstream of the gryone from scouring away
3. downstream of the groyne from silting up
4. downstream of the groyone from scovring away

Q82.The width of a meander belt is the transverse distance between

1. apex point of one curve and the apex point of the next reverse curve
2. apex point and the crossing
3. two banks of meandering river
4. two successive apex points on the same bank

Q83.Surface drains are designed for

1. seepage flow and storm run-off
2. strom run-off only
3. strom run-off and surface flow resulting from excess irrigation
4. excess irrigation flow only

Q84.A tile drainage system draining 12 hectares, is designed using a drainage coefficient of 1.25 cm. The volume of water removed, at the designed capacity from the area in 2 days following a 12 hour storm is

1. 750 cu.m
2. 1500 cu.m
3. 3000 cu.m
4. 6000 cu.m

Q85.Attracting spurs are those which

1. makes usually angle of 90° with the bank
2. points downstream of the river
3. points upstream of the river
4. protects the bank from the attack of river current

Q86.Herring bone layout of drainage system is effective

1. In rolling topography
2. When the land slopes in one side
3. When the land to be drained is a hilly terrain
4. When the drain is laid in a degression

Q87.For natural rivers, the discharge which determines the meandar length and meander belt may be called

1. normal discharge
2. Maximum discharge
3. dominant discharge
4. low flow discharge

Q88.As far as possible the diagram of embankment of any point is respect to direction of run-off should be

1. Parallel
2. at an angle of 30°
3. at an angle of 60°
4. at right angle

Q89.In non-cohesive soils, the depth of scour, calculated by lacey's formula gives scour depth below the

1. bed level of the river
2. highest flood level
3. normal water level
4. low water level

Q90.The upstram curved head of a guide bank should have a sweep angle of

1. 90°-100°
2. 120°-145°
3. 125°-150°
4. 130°-160°

Q91.Froude number (F) is expressed by the relation

1. V/(V⁰√gd)
2. v×d
3. v×√gd
4. √gvd

Q92.Water logging

1. improve soil operation
2. is good for tillage operation
3. minimum ise soil arraction
4. removes water weeds

Q93.Culvert are provided on road emankments

1. in areas having no defined channel to carry surface run off
2. over canals
3. over hilly streams
4. when the road passes throught a small valley

Q94.With some size of catchment area, the bass of the direct run off hydrograph will desrease with increse in

1. channel length
2. forest cover
3. permeability to the soil
4. slope of the catchment

Q95.The bridge site should selected so that

1. flow lines are parallel to bank lines
2. flow lines are angular to bank line
3. non uniform flow conditions exist
4. the site is at a bend

Q96.Spurs are least effective in

1. channel improvement for natigation
2. protecting the river bank
3. training the river long a desired course
4. confining the flood water of alluvial rivers within reasonable waterway

Q97.Weeds in surface drains loads to

1. increase in the value of coefficient of rugosity
2. reduced resistance of flow
3. increase in command area
4. improved waterway