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Irrigation Engineering
Q.1 The example of auxiliary water resource is
(a) spring (b) open wells(c} sewage disposal (d) fog
Q.2 Which of the following is a costlier system?(a} gravity irrigation
(b) lift irrigation(c) combination (a) and (b)(d) drip irrigation
Q.3 Volumetric method of assessment leads to
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a.a
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(a) higher duty (b) lower duty(c) nominal duty (d) has no impact on duty
Use of Potassium permanganate in water makes it (a) odourless (b) transparent(c) colourless (d) non-turbid
The sensitivity of a rigid module is (a) 0.01 (b) 0.1(c) 1 (d) O
Which of the following is a flexible outlet? (a) glacis fall(b) Kennedy's gauge outlet(c) Gibb's outlet(d) canal outlet
In an ogee spillway, the discharge is proportional
to (a) H1l2
(c) ,-p12(b) H5l2
(d) H5l4
Hydrodynamic pressure due to earthquake acts
at a height of (a) 3H/4n above the base(b) 3H/4n below the water surface(c) 4H/3n above the base(d) 4H/3n below the water surfacewhere H is the depth of water.
Presence of tail water in a gravity dam
(i) increases the principal stress(ii) decreases the principal stress(iii) increases the shear stress(iv) decreases the shear stress
The correct answer is
(a) (i) and (iii) (b) (i) and (iv)(c) (ii) and (iii) (d) (ii) and (iv)
Q.10 By providing a top width for roadway andfreeboard in the elementary profile of a gravity dam, the resultant force for full reservoir condition
will (a) shift towards the heel(b} shift towards the toe(c) not shift at all( d) none of the above
Q.11 For wave action in dams, the maximum height offreeboard is generally taken to be equal to (a) 0.5 h
w (b) 0.75 h
w
(c) 1.25 hw
(d) 1.50 hw
Q.12 Seepage through embankments in an earthendam is controlled by (a) drainage filters(b) relief wells(c) drain trenches(d) provision of downstream berms
Q.13 In case of non-availability of space due totopography, the most suitable spillway is (a) straight drop spillway(b) shaft spillway(c) chute spillway(d) ogee spillway
Q.14 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.
Q.15 According to Khosla's theory, the exit gradient inthe absence of a downstream cut-off is (a) 0 (b) unity(c) infinity (d) very large
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'.:Q.16 The minimum size of stone that will remain at Q.25 Main purpose of mean water training for riversisrest in a channel of longitudinal slope S and (a) flood control.
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hydraulic mean depth R is given by (b) to provide sufficient_ depth of water in(a) 4 RS (b) 11 RS navigable channels, dunng low water PeriOd (c) 7 RS (d) 15 RS (c) to preserve the channel in good shape b:If the critical shear stress of a channel is 't then efficient disposal of suspended and bed load.
� b the average value of shear stress required to (d) all of the a ove
move the grain on the bank is (a) 0.5-rc (b) 0.75-rc(c) 'tc (d) 1.33 'tc
According to Lacey's theory, the silt supporting eddies are generated from (a) bottom of channel only(b) sides of channel only(c) bottom as well as sides of channel(d) none of the above
According to Lacey, the bed slope is given byf�3 tV3 (a) 33400112 (b) 33400114
,s/3 (c) 33400116
,113 (d)
33400513
Wetted perimeter of a regime channel for a discharge of 64 cumecs as per Lacey's theory will be (a) 19 m(c) 57 m
(b) 38 m(d) 76 m
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If the coefficient of variation of rainfall values at 4 rain gauge station is 30% and permissible error in the estimation of mean rainfall is 10%, then the additional number of rain gauge stations required in the catchment is (a) 3 (b) 4(c) 5 (d) 9
In a siphon aqueduct the most severe condition of uplift on the floor occurs when (a) canal runs full, drain is dry but the water table
is at stream bed.(b) canal is dry and drain i� at high flood level.(c) canal runs dry and the drain also runs dry.(d) both the canal and the drain run full.
Q.28 Cross-regulators in main canals are provided to(a) regulate water supply in the off-taking channel.(b) regulate water supply in the main channel.(c) regulate excessive flood water.
Q.21 For a proportional outlet , the flexibility is(d) head up water for adequate supply into the
off-taking channel.(a) zero (b) between zero and 1(c) 1 (d) greater than 1
Q.22 The sensitivity of a rigid module is(a) zero (b) between zero and 1(c) 1 (d) infinity
Q.23 Which of the following canal outlets maintains aconstant discharge? (a) non-modular outlet(b) flexible outlet(c) rigid module(d) none of the above
Q.24 Tortuosity of a meandering river is the ratio of(a) meander belt to meander length.(b) meander length to meander belt.(c) curved length along the channel to the direct
axial length of the river reach.( d) direct axial length of the river reach to curved
length along the channel.
0.29 For the upstream slope of an earth dam, the most critical condition is (a) sudden drawdown condition.(b) steady seepage condition.(c) neither sudden draw down nor steady
seepage condition. (d) during construction when the reservoir is
allowed to be filled.
0.30 The sequent peak algorithm is a method used inthe estimation of the (a) maximum possible precipitation in a basin.
(b) maximum possible flood peak in acatchment.
(c) minimum evapotranspiration from acatchment.
(d) minimum reservoir capacity needed to meeta given demand.
f ' b ' conjuctive use o water ,n as me s0-3
1 (a) combined use of water for irrigation and for
hydropower generation.(b) combined use of surface and ground water
resources.(c) use of irrigation water for both rabi and kharif
season.(d) use of irrigation water by cooperative of
farmers.
Q.32 Rigid boundary canals, whose bed and banksare made with non-erodible materials, are in
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(a) true regime (b) permanent regime(c) final regime (d) none of above
The following parameters relate to the design of weirs on permeable foundations: 1. scour depth 2. exit gradient3. uplift pressure 4. unbalanced headDesign of the downstream end pile of the weirdepends upon:(a) 1 and 2(c) 2 and 3
(b) 1 and 4(d) 3 and 4
A culvert is designed for a peak flow O on the basis of rational formula. If a storm of the same intensity as used in the design and twice the duration occurs, then the resulting peak discharge will be
(a) 0p
(b) OP
2(d) 2 OP
The irrigation engineering may be defined as (a) the process of artificially supplying water to
soil for raising crops.(b) a science of planning and designing an
efficient and economic irrigation system.(c) the engineering of controlling and harnessing
the various natural sources of water, by theconstruction of dams, canals and finallydistributing the water to the agricultural fields
(d) all of the aboveFor irrigation purposes, the pH value of watershould be (a) between 3 and 6(b) between 6 and 8.5(c) between 8.5 and 11(d) rnore than 11
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When an oven-dried sample of soil is kept openin the atmosphere, it absorbs some amount of water. This water is known as (a) capillary water (b) gravitational water(c) hygroscopic water (d) all of these
A useful soil moisture for plant growth is(a) capillary water (b) gravitational water(c) hygroscopic water (d) all of these
Q.39 The amount of water required to fill up the porespaces in soil particles by replacing all air held in pore spaces, is known as
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(a) field capacity (b) saturation capacity(c) available moisture (d) all of these
The water content at which plants can no-longer extract suf'ficient water from the soil for its growth is called (a) field capacity(b) saturation capacity(c) permanent wilting point(d) available moisture
Available moisture may be defined as the(a) moisture content at permanent wilting point(b) difference in water content of the soil between
field capacity and permanent wilting (c) maximum moisture holding capacity( d) al I of these
The field capacity of a soil depends upon(a) capillary tension in soil(b) porosity of soil(c) either (a) or (b)(d) all of these
The ratio between the area of a crop irrigated and the quantity of water required during its entire period of the growth, is known as (a) delta (b) duty(c) base period (d) crop period
The duty is largest(a) at the head of the main canal(b) at the head of the water course(c) on the field(d) at all place
Cro� ratio is the ratio of area irrigated(a) in Rabi season to Kharif season(b) in Kharif season to Rabi season(c) under perennial crop to total crop(d) under perennial crop to non-perennial crop
\.l.4b
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rhe duty of irrigation water will be less if(a) area irrigated is more (b) water supply required less (c) water supply required is more( d) none of these
The first watering before sowing the crop, is known as (a) kor watering(c) delta
(b) paleo( d) none of these
The maximum depth in soil strata, in which the crop spreads its rot system, and derives waterfrom the soil, is called (a) kor depth (b) root zone depth(c) delta (d) overlap allowance
The precipitation caused by lifting of warm moisture laden air masses due to topographic barriers, is called (a) convective precipitation(b) orographic precipitation(c) cyclonic precipitation( d) none of these
According to Dicken's formula, the flood discharge ( Q) in cumecs is given by (a) Q = CA213 (b) Q = CA3l4 (c) Q = CA516 (d) Q = CA718
where, C = Flood coefficient and A = Area of basin in sq km.
Inglis formula is used for estimating flood discharge for (a) the catchments of former Bombay Presidency(b) the catchments of old Hyderabad State(c) the Madaras catchements(d) none of the above
Q.52 A hydrograph representing one cm of run-off from a rainfall of some unit duration and specific area distribution is known as
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(a) hyetograph (b) flood hydrograph(c) unit hydrograph (d) S-hydrograph
In a canal section, which is in partial filling and partial cutting (a) the full supply level of the canal is above the
natural surface level (b) the bed level of the canal is below the natural
surface level (c) the full supply level of the canal is below the
natural surface level( d) the bed level of the canal is above the natural
surface level
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Garret's diagram gives the graphical meth d designing a channel based on ° I (a) Lacey's theory (b) Gibb's theory I(c) Kennedy's theory (d) Khosla's theory IThe relation given by Kennedy for critical velocilin m/s is I (a) Vo = 0.55 mO°·64 (b) Vo = 0.64 mO0.65 I (c) Vo = 0.74 mO° ·84 (d) Vo = 0.84 mo0.74 I where, m = Critical velocity and O = Depth !water over the bed portion of a channel in metrej
According to Lacey I (a) the silt is kept in suspension due to the tord
of vertical eddies I (b) the eddies are generated from bed and side�
both normal to the surface of generation I(c) the vertical component of eddies from side!
will also support the silt (d) all of the above I
If m is the mean particle diameter of the silt i) mm, the Lacey's silt factor (f) is given by
I(a) f = 1.76 m 112 (b) f = 1.76 m312
(c)f=1.76m2 (d)f=1.76m512 I
Cross regulators are provided I
(a) to raise the water level to its upstream duringl
the periods of low discharges in the parentl channel I
(b) to help in closing the supply to down streamof the parent channel
(c) to absorb fluctuation in various sections ofthe canal system
(d) all of the above
Q.59 A parabolic glacis type fall is commonly known as(a) Montague fall (b) Inglis fall(c) Sarcia fall (d) vertical type fall
Q.60 Gibb's module is a type of(a) non-modular outlet(b) semi-modular outlet(c) rigid modular outlet(d) open flume outlet
Q.61 The sensitivity of an outlet is defined as the ratio of the (a) rate of change of discharge of an outlet to
the rate of change of discharge of the distributing channel
(b) rate of change of discharge of an outlet to therate of change in level of the distributingsurface, referred to normal depth of the channel
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(c) depth of the sill or the crest level of the modulebelow the full supply of the distributingchannel to the full supply depth of thedistributing channel
(d) head recovered to the head put in an outlet
In Bligh's creep theory, it is assumed that thepercolation water creep (a) along the contact of the base profile of the
apron with the sub-soil(b) in a straight path under the floor(c) in a straight path under the foundation work(d) none of the above
Q.63 In Lane's weighted creep theory, he proposed aweight of (a) three for vertical creep and one for horizontal
creep(b) three of horizontal creep and one for vertical
creep(c) two for vertical and two for horizontal creep(d) any one of the above
Q.64 A hydraulic jump is formed when(a) a sub-critical flow strikes against a super
critical flow
(b) a super-critical flow strikes against a subcritical flow
(c) the two flows of super-critical velocity meeteach other
(d) the two flows of sub-critical velocity meet eachother
0.65 A river meandering through an alluvial plain hasa series of consecutive curves of reversed order
connected with short straight sketches, is called(a) crossing(b) meandering belt(c) meandering length(d) none of these
0-66 A drainage coefficient (a) decides the choice of the meth0d of the
drainage (b) decides the kind of crop that can be grown
on the land ved (c) is the depth of water that can be remo
from the drainage area in unit time. t·ie'I ' to the I (d) is the flow of water from the soi in
laterals per unit time
Q.67 Semi-module outlets are those outlets in which(a) discharge gets affected by the change in
water level of field channel(b) discharge gets affected by the change in
water level of the distributing channel but notwith the change in water level of field channel
(c) discharge is independent of water levels inthe distributing channel and the field channel
(d) None of the above
0.68 In a canal irrigation project, 76% of the culturable command area (CCA) remained without water during Kharif season ; and 58% of CCA remained without water during Rabi season in a particular year. Rest of the areas got irrigated in each crop respectively. What is the intensity of irrigation for the project in the year ? (a) 134% (b) 76%(c) 66% (d) 58%
Q.69 An identified source of irrigation water has ionconcentrations of Na+, Ca++ and Mg++ as 20, 1 O and 8 milliequivalent per litre, respectively. The SAR of this water is approximately (a) 2.06 {b) 6.67 (c) 2.67 (d) zero
Q.70 A field measures 40 hectares. When 8 cumecsof water was supplied for 6 hours, 30 cm of water was stored in the root zone. The field application efficiency is nearly. (a) 70%(c) 85%
{b} 80%{d) 90%
Q. 71 Consumptive Use refers to the loss of water as aresult of (a) Evaporation and Transpiration{b) Crop Water Requirement(c) Evaporation and Infiltration(d) Evaporation and Transpiration from the
cropped area
Q. 72 Consider the following statements in connectionwith soil-water-crop relationship: 1. Water utilization by plants is mainly from
capillary water.2. The amount of irrigation water required to meet
the evapotranspiration needs of the cropduring its full growth duration is itsconsumptive irrigation requirements.
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3.
4.
Th� depth of water required to bring the soil-moisture level f • . . . 0 a given soil up to its fieldc�pac1ty is called hygroscopic water. With _continuous increase in quantity of waterapplied, t�e �i�ld of most crops increase upto a certain hm1t and then is expected to beconstant. Which of the above statements are correct?(a) 1 and 2 (b) 2 and 3
.
(c) 3 and 4 (d) 1 and 4For medium silt whose average grain size is0-16 mm, Lacey's silt factor is likely to be(a) 0.30 (b) 0.45(c) 0.70 (d) 1.32The Lacey's silt factor for a particular alluvium is2.0. This alluvium would comprise (a) medium sand of size 0.5 mm(b) coarse sand of size 0.75 mm(c) medium bajri of size 1.3 mm(d) coarse bajri of size 2.4 mm
In alluvial channels carrying clear water, the ratio of maximum tractive shear stress on the sides and that on the channel bed is approximately (a) 0.5 (b) 1.76(c) 0.76 (d) 1.5
The total number of independent equations that form the Lacey's regime theory is (a) 2 (b) 3(c) 4 (d) 6
Balanced depth of cutting of canal is(a) half the total depth of a canal(b) half of full supply depth(c) the maximum cut that an excavator can take(d) where volume of cutting is equal to volume
of filling
Modular limit of a canal outlet is the ratio of (a) rate of change of discharge of outlet to that
of distributary.(b) water depth above outlet crest to the full
supply depth of the channel(c) water depth above the crest on downstream
to that on upstream of outlet(d) rate of change of discharge of an outlet to
the rate of change of water level of the channel.
A canal fall is a control structure
(a) located at a place where the country slope is
flatter than the canal bed slope
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(b) located most economically where the d f t · · epth o cu tin� 1s less than the balancing depth (c) the location of which is independent of the
command to be served(d) designed to secure raising of water surface
on its upstream
In Lacey's regime theory, the velocity of flow isproportional to (a) Qf2 (b) Q/f2
(c) (Qf2)1l6 (d) (Q/f2)1/6
Garret's diagrams are used to (a) separate base flow from total runoff(b) correct inconsistency in rainfall data(c) determine reservoir capacity(d) design channels
Critical shear stress of cohesive sediment(a) Decreases with the void ratio for a given
plasticity index.(b) Increases with the plasticity index for a given
void ratio(c) Increases with shear strength for a given clay
content( d) All of the above
A channel designed by Lacey's theory has a mean velocity of 1.1 m/s. The silt factor is 1.1. Then hydraulic mean radius will be (a) 1.13 m (b) 2.27 m(c) 3.13 m (d) 4.27 m
The construction of impounding reservoir is required when (a) average annual flow in the stream is lower
than average demand(b) the rate flow in the stream, in dry season is
more than the demand(c) the rate of flow in the stream, in dry season
is less than the demand(d) the rate of flow in the stream is equal to the
demand
If p is the specific gravity of the material used in the design of a masonry dam of triangular section, then the ratio between the height and base width of the dam for structural safety and stability is equal to (a) ftp (b) ✓P
1 1(c) - (d) ✓P
p
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best design of an arch dam is when (a) depth of drain below the ground surfaceQ.86 The II horizontal water loads are tranc:fcrrod (b) depth of impervious strata from tt1e drain
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(a)
�orizontally to the abutments (c) cJepth of drain below the water level
(b) t he dam is safe against sliding at v1_:1rious (d) coefficient of permeability of the soil to be
levels drained ) the load is divided between the ar
.c ·tws a.nd . . tt (c
c antilevers and the deflections at the conjugal Q.93 The ideal condition for energy dissipation 1n 1edesign of spillways is tt1e one when the tail water Points being equal rating curve (d) the deflections of the cantilevers are equal at(a) lies above jump rating curve at all dischargesdifferent points (b) coincides with the jump rating curve at all
A constant angle arch darn when compared to a constant radius arch dam utilizes concrete quantity of about (a) 33%
(c) 73%
A check dam is a
(b) 43%(d) 143%
(a) flood control structure(b) soil conservation structure(c) river training structure(d) water storage structure
The base width of a solid gravity dam is 25 m. The material of the dam has a specific gravity of 2.56 and the dam is designed as an elementary profile ignoring uplift. What is the approximate allowable height of the dam? (a) 64 m (b) 40 m(c) 164 m (d) 80 m
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discharges(c) lies below jump rating curve at all discharges(d) lies either above or below the jump rating
curve depending upon discharge
Leaching is a process (a) by which alkali salts present in the soil are
dissolved and drained away(b) by which alkali salts in soil come up with water(c) of draining excess water of irrigation(d) which controls water-logging
Which one of the following is the purpose of providing the downstream sheet pile in a barrage? (a) To control failure due to piping by high value
of exit gradient(b) To control failure due to scour(c) To stop failure due to sliding(d) To stop failure due to uplift pressure
0.90 What is the critical combination of vertical and horizontal earthquake accelerations to be considered for checking the stability of a gravity dam in reservoir full condition ?
Q.96 By considering the channel index as 5/3, the setting of an orifice type irrigation outlet to have proportionality is (a) 0.90(c) 0.30
(b) 0.67(d) 0.15
Q,91
(a) Vertically upward and hor izontal lydownstream
(b) Vertically upward and horizontally upstream(c) Vertically downward and horizontally upstream(d) Vertically downward and hor_
izontallydownstream
A constant centre (in plan-view) arch dam is beSt suited for (a) AV-shaped gorge(b) AU-shaped gorge (c) Both U-shaped and V-shaped gorges(d) Multi-peaked gorges
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The spacing of tile drains to relieve water-loggedland is directly proportional to the
Q.97 A 20 m long horizontal concrete floor under a barrage on a permeable foundation retains a 5 m head of water and has a 5 m deep downstream end pile. The exit gradient is (a) 1 in 4 (b) 1 in 5(c) 1 in 6 (d) 1 in 8
Q.98 The most economical method of soil conservation is to (a) construct check dams(b) construct contour bunds(c) drain the soil(d) afforest the area
Q.99 Whe� a river starts meandering, the sedimentcarrying capacity(a) first decreases and ultimately increases(b) first increases and ultimately decreases (c) remains unaffected as the plan shapechanges continuously(d) changes erratically all the time leaving
permanent braids
Q.100 Gibb's module is a type of outlet which ensures(a) constant discharge even if the water levels
in the supply channel and water coursefluctuate
(b) variable discharge as per the need(c) constant discharge into the water course when
the water levels in the supply channel vary (d) constant discharge for varying water levels
in the water course for a given water level inthe supply channel
Q.101 The following data pertain to a natural draincrossing an irrigation canal:
Item Canal Drainage data data
Flow (m3/s) 5 500 Bed level (m) 120 116 Depth of flow (m) 0.8 10
Which one of the following types of crossdrainage should be recommended in this case? (a) Aqueduct (b) Syphon aqueduct(c) Syphon (d) Super-passage
Q.102 In a river, silt excluder and silt ejector areconstructed (a) at a location after the head regulator and at
the head of the canal, respectively(b) at the head of the canal and at a location
after the head regulator, respectively(c) at the same location(d) at specific locations depending upon diverse
factors and their locations do not follow a setpattern
Q.103 The worst condition of uplift on the floor of asyphon aqueduct occurs when there is (a) high flood flow in the drainage with canal dry(b) full supply flow in the canal with drainage dry(c) high flood flow in the drainage with canal
running full(d) Water is at drainage bed and canal is dry
Q .104 Denehy's groyne is a special type of groyne Whichis (a) pointing upstream (b) pointing downstream(c) Hockey type (d) T-headed
Q.105 Groynes are adopted for river bank protectionworks. When it is placed inclined downstream in the direction of flow in the river, it is designated as which one of the following? (a) Repelling groyne(b) Attracting groyne(c) Neither repelling nor attracting groyne(d) Fixed groyne
Q. 106 For calculating the maximum flood discharge in analluvial stream, which is the best suited relation? (a) Voe R2I3S1!3 (b) Voe R2I351I2
(c) voe R1I2 5112 (d) voe 0064
Q.107 A submerged pipe outlet is an example of(a) semi-modular outlet(b) non-modular outlet(c) rigid module(d) adjustable proportional module
Q.108 If the channel index at an irrigation outlet is 5/3,"setting" of an orifice type outlet in order to have proportionality is (a) 0.90(c) 0.30
(b) 0.67(d) 0.15
Q.109 The water utilizable by plants is available in theform of (a) gravity water (b) hygroscopic water(c) capillary water (d) chemical water
Q.110 On rolling land, the method of applying water is(a) Check flooding (b) Free flooding(c) Border flooding (d) Furrow flooding
Q.111 Intensity of irrigation is(a) The percentage of culturable commanded
area proposed to be irrigated annually(b) Is always more than 100%(c) Is the percentage that could be ideally irrigated(d) All options are correct
Q.112 The field irrigation requirement is computed as(a) Consumptive use + field application losses(b) Net irrigation requirement+ field application
losses(c) Net irrigation requirement + conveyance
losses(d) Consumptive use+ conveyance losses
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�gree of sinuosity is the ratio bGlW00r1 the113 me t: · • . Q. ) llt"''nder length to w1<ith of meandor
(a. I ·-' . • b) ,neander length and the w1cith of river
�c) curved length and the straight air distance(d) none of t11ese
14 A submerged weir is one in wl1ich the water level0- 1 .,... f tt .. 011 t11e down stream s1ue o 1e weir 1s:
(a) just at tt1e crest level(b) below tt1e crest level( �) above crest level
tti) at same elevation as water surface onup ... strearn
Q.115 Li i g of irrigation canals (a) de•'reases the waterlogging of an area( ) in reases the waterlogging of an area (c does not change the waterlogging of an area( ') increase evaporation
Q. 16 ,i·,er training work is generally required whenme river is (a) aggrading type (b) meandering type(c) degrading type (d) both (a) and (c)
Q. 17 ro• 1:�ed canals, the freeboard is measured from
(e) ;u:J s ·pply level to the top of the lining.(b) fu!i supply level to the top of the bank.(c) to t e bank to the top of the limit. (d) iul: su � ly level to the top of the down.
0. i 8 A Ga'.";al d<::signed to irrigate throughout the yearIS(a) Per kine, t u;n;:il(b) P<::-r&nnid car al (c) Conti uous canal(d) Gr&E:n can::11
Q.119 Ca al nurrnally used for divorsion of flood watorof a river is (a) Feeder canal(c) Ridge Canal
(I)) l11unda1irm can:11(d) Contour c:111al
0· 120 The 'surct1arge storage' in a <Jam rosorvoir is tt10voiume of water stored between (a) minimum and maximum reservoir lovols(b) minimum and normal reservoir levels (c) normal and maximum reservoir levels(d) None of these
0.121 Berms are provided in canals if these are(a) fully in excavation (b) partly in excavation and partly in embankment(c) fully in embankment (d) all options are correct
Q.122 The hydraulic radius is given by (a) wetted perimeter divided by area (b) area divided by square of wetted perimeter(c) area divided by wetted perimeter(d) square root of area
Q.123 The sensitivity of a rigid module is (a) equal to unity . (b) less than unity (c) equal to zero (d) more than unity
Q.124 If the discharge in a canal equals 70 m3/s with
silt factor of ✓2 . The velocity of flow in canal asper Lacey's theory is:(a) 0.5 m/s(c) 1.0 m/s
(b) 0.75 m/s(d) 1.25 m/s
Q .125 Volumetric method of assessment leads to :(a) higher duty(b) lower duty (c) nominal duty (d) has no impact on duty
Q.126 The suspended silt concentration in a channelcarrying silt load is : (a) lower at bottom layers than upper layers (b) higher at bottom layers than upper layers(c) uniform in bottom and upper layers (d) lower in upper and bottom layers but higher
in middle layers
Q.127 The thickness of concrete lining is governed by(a) requirement of imperviousness (b) requirement of imperviousness and structural
lrunott1 (c) capacity of canal (cl) •'lopo of bank of canal
0.128 In caso of nravity cjarn subjected to Earthquake, tt1e llydro cjynamic pressure variation curve isoonorally t,1kon to be(n) Parabolic(b) Elliptical (c) Triangular (d) Elliptical cum Parabola
0.129 According to Casagrande's method of determining phreatic line in an Earthern Dam with horizontal filter, the starting point of top parabola is located at (a) 0.5L away from cutting edge(b) 0.3L away from cutting edge(c) 0.2L away from cutting edge(d) 0.1 L away from cutting edge
where Lis the horizontal projection of upstreamslope, lying below water surface.
Q.130 Of the following spillway crest gates, the leasthuman/mechanical effort to operate is required for (a) Flash boards(c) Radial gates
(b) Vertical lift gates
(d) Drum gates
Q.131 In a dam project with high side and narrow gorge, the most suit type of spillway is (a) Side channel spillway(b) Ogee spillway(c) Chute spillway(d) Syphon spillway
Q.132 Irrigation canals are generally aligned along(a) contour line (b) watershed line(c) valley line (d) parallel to valley line
Q.133 The elementary profile of a gravity dam is(a) a trapezoid(b) a right angled triangle(c) a rectangle(d) an equilateral triangle
Q .134 An outlet is said to be proportional if the flexibility is (a) less than unity(c) equal to unity
(b) equal to zero(d) more than unity
Q.135 When an irrigation canal is constructed over a
drainage channel, the crossing is called (a) An aqueduct (b) A super passage
(c) Canal regulator (d) Canal syphon
Q.136 In case of gravity darn subjected to earthquake,
the hydrodynamic pressure variation curve is
generally taken to be
(a) Elliptical
(b) Parabolic
(c) Triangular
(d) Elliptical cum Parabolic
Q.137 According to Khosla's theory, the undermining
of the floor starts from the
(a) Tail end
(b) Starting point
(c) Intermediate
(d) Tail edge of the foundation bed
Q.138 Which of the following spillway is least suitable
for an earthen dam?
(a) ogee spillway
(b) chute spillway(c) side channel spillway(d) shaft spillway
Q.139 The width of launching apron is generally equal
to (a) 1.50 (b) 2.00
�)0.90 �)2.80
where O = depth of scour below original bed level
Q.140 Lacey's regime scour depth is given by
( 2
)1/6
(b) 1.35 �
( 2
)1/3
(c) 1.35 � ( )1/3
(d) 1.35 j where q is discharge per unit width and f is silt factor.
Q.141 Maximum wave pressure on the face of dam
occurs of khw, where hw is the height of wave
pressure and khw is given by
3 (a)
8 hw above still water level
3(b)
8 hw below still water level
1 (c)
8 hw below still water level
1(d)
8 hw above still water level
Q.142 The term 'consumptive use' of water for a crop
means (a) Loss of water, as depth due to evaporation
from land surface(b) Loss of water, as depth, due to transpiration
from leaves(c) Loss of water, as depth from evapo
transpiration(d) Evaporation loss minus rainfall occurred
"11yduon tngineering I 367 =---:-��-----::..__-=���-------_!��
::,..---- base width of the elementary profile of a 0.150 A channel aligned nearly parallel to the naturalQ. 1 43 :�:vity dam wl1en the uplift pressure is neglected drainage of an area is called: � given by (a) Side slope channel
H (b) Contour channel (a) G (c) Water shed channel
H (d) Ridge channel(b) JG
H H
(c) Greater of JG and µG
H H
(d) Lesser of JG and µG
w11ere, H = Depth of water upstream G = Specific weight of dam material µ = Coefficient of friction
Q.144 Due to water logging the salt contents rise andsoil becomes infertile when pH value becomes (a) 5 (b) 7(c) 9 (d) 11
Q.145 The upstream face of an earth dam is a(a) Flow line(b} An equipotential line(c) Phreatic line(d) Atmospheric pressure line
Q.146 The moisture tension for a soil is 8 atmospheres.The soil is then at (a) permanent wilting point(b) field capacity(c) optimum moisture content(d) equivalent moisture
Q.i47 Kennedy assumed in his silt theory that the siltis kept in suspension due to eddies generated from: (a) bed only (b) sides only(c) whole perimeter (cJ) water surface
0· 148 Garret diagram gives the graphical meth0d ofdesigning an irrigation channel t)ased upon
(a) Lacey's theory (b) Kt1osla's tt1eory (c) Gibb's theory (d) Kennedy's theory
0.149 Th · ·murn during:e Water requirement of crop 1s maxi (a) first watering before sowing Hie crop (b) first watering when the crop has grown a few
centimetres (c) last watering before harvesting (d) intermediate watering between (b) and (c)
0.151 A cylinder or well fall is suitable and economicalfor:(a) High discharges and high drops(b) High discharges and low drops(c) Low discharges and high drops(d) Low discharges and low drops
Q .152 The depth of an open well is normally limited to:(a) 8m (b) 13m(c) 30 m (d) 80 m
Q.153 In case of a gravity dam, subjected to earthquake, the hydrodynamic pressure variation is taken to be (a) parabolic(b} elliptical(c) triangular(d) elliptical cum parabolic
Q.154 According to Khosla's theory, the exit gradient in
the absence of a downstream cutoff is (a) zero (b) unity(c) infinity (d) very large
Q.155 The sensitivity of a rigid module is (a) equal to zero (b) less than unity(c) equal to unity (d) more than unity
Q. 156 An outlet is said to be proportional if the flexibility is (a) equal to zero(c) equal to unity
(b) less than unity(d) more than unity
Q.157 The elementary profile of a dam is (a) a rectangle(b} a trapezoid (c) a right angled triangle(d) an equilateral triangle
Q. 158 A canal headwork in rocky stage of a river is not suitable because (a) a costly t1ead regulator is required(b) more falls are necessary to dissipate the
energy(c) more cross drainage works are required(d) All of these
Q.159 Silt < joctors nre providnd us silt controllinn cit)vico� on (H) upstrt nrn of a cn11nl hflncl moulnlor(b) cjownstroam of a canal hoacl r( oulator(c) upstrnrnn of a spillway(<i) downsln am of a spillway
Q.160 lrrinntion canal� arn gonernlly aligned along (n) Walmshoci line (t,) Contour line(c) Vall iY line (d) Parallel to v·:1.ll0y line
Q .161 Sprinkler irrigation is an irri9ation method for which the following statements are made 1. It requires el·:ibomte preparation of land before
irri9ntion.2. It leads to excessive irrigation and water
logging.3. Initial investment and power requirement is
high.4. Strong wind will disrupt irrigation application.Of the above statements(a) all are correct(b) only three statements are correct(c) only two statements are correct(d) only one statement is correct
Q.162 The most suitable method of irrigation for areas having low rainfall and strong winds is (a) sprinkler irrigation (b) drip irrigation(c) furrow irrigation (d) free flooding
Q.163 A canal wl1ich can irrigate only on one side, is known as (a) contour canal (b) side slope canal(c) watershed canal (d) None of these
Q .164 It the flood discharge flowing in a river is 3600 1113/s, its perimeter as per Lacey's theory is likely to be (a) 360 m (b) 300 rn(c) 285 m (d) 270 rn
Q.165 The rivers in flood plains can be classified as(a) Aggrading (b) Degrading(c) Stable (d) Oeltic
Q .166 Spur is a structure used tor (a) Protecting the banks of rivers and canals(b) extracting sediment from flow(c) diverting flow of water to canal( d) none of these
Q. 167 The salt concentration in irrigation water should not exceed {a) 2000 ppm (c) 2500 ppm
(b) 3000 ppm (d) 500 ppm
Q.168 The ratio of the qwmt.ity of Wf:JIDr storucJ ir 1
1 root zone o� tho crops t� the_ qu,;intity of v11actually cjoltvorod In the field Is known &-55 (a) wat()r conveyance effici(::ncy(b) water application efficiency(c) water use efficiency(d) none of the above
Q.169 Infiltration capacity(a) is a constant factor(b) changes with time(c) changes with locat;on(d) changes with both time and location
Q.170 If allowable percentage err�r_in the est'.m�tr,
1 basic rainfall is E and coefficient of vanat,or1
rainfall is Cv, then the optimum then the optirri:j number of raingauges is given by
Cv (a) E (b) fi-
(C )312(d) _x.
E
Q.171 A 70% index of wetness means (a) rain excess of 30%(b) rain deficiency of 30%(c) rain deficiency of 70%(d) none of the above
Q .172 The useful storage is the volume of water store. in the reservoir between I(a) minimum pool level and maximum pool lever 1
1 (b) minimum pool level and normal pool level.I (c) normal pool level and maximum pool level. I (d) river bed and minimum pool level. I
Q .173 Trap efficiency of a reservoir is a function of(a) capacity/inflow ratio(b) capacity/outflow ratio
I I I
(c) outflow/inflow ratio(d) none of the above
Q.17 4 The uplift pressure on a dam can be controlled by (i) constructing cut-oft under upstream face.(ii) constructing drainage channels between th8
dam and its foundation. (iii) by pressure grouting in foundation.The correct answer is(a) only (i) (b) both (i) and_\ii)(c) both (i) and (iii) (d) (i), (ii) and (111)
real crops the most c0rnrnordy adnplr:(J
75 Force . . a. 1 method of irrigation, 1£
(a) free flowing method
(b) check metriod
(c) furrow m0tr1od
(d) sprinkling m0thod
76 Pick up the incorrect statement frorn thf..: frJllr.tNing:Q. 1 d. . . t· t . J • (a) In tree floo 1ng 1rnga ion, wa <'Jr 1..; ar rn1tt0d
at one corner of a fir .. dd and is allcJwr;c.J to spread over the entire area
(b) In check method of irrigation, I.he fie:lcJ i�divided into smaller compartments 8ncJ wr:it<::ris admitted to each in turn
(c) In furrow irrigation water is admitted bc::twc:r..:nthe rows of plants in the fi<::ld
(d) None of these
Q.177 Irrigation canals are generally aligned along (a) ridge line (b) contour line(c) valley line (d) straight line
Q.178 Culturable commanded area is the gross area of an irrigation canal system less (a) populated area (b) alkaline area(c) forest area (d) fallow land
0.179 Water-shed lines is abandoned for aligning an irrigation canal if (a) water shed forms a sharp loop(b) canal has to take off from a river(c) towns and villages are located on the water
shed line(d) all the above
0-180 If Band d are the bed width and depth of a Ch8nnel in metres, the combined IOS$,eS due to evaporation and seepage in cumecs per kilometrelength of the channel, is
(a) J__ (8 + d)21350 (b) _1_ (B + d)2/3
100
(c) 151
0 (8 + d)213 (d) _1_ (B + d)2/3200
a.,a, R . egirne conditions in a channel may occur 1f (a) discharge is constant (b) channel flows uniformly in incoherent alluvium
as that transported in suspension (c) silt grade and silt charge are constant(d) all the above
Q, 182 Lac;1::y's regime condition is obtained i f (c.1) silt grade in the channel is variable (b) discharge in the channel is variable(c) silt charge in the channel is variable(cJ) channel flows in unlimited, incoherent alluvium
of the same character as that transported matt=Jrial
Q, 183 Pick up the correct statement from the following: (a) The full supply level of a canal should be
above ground level (t)) According to Lacey, regime conditions
require a particular slope for a given discharge and silt factor
(c) In case the ground slope is less than therequired bed slope, the silt factor must be reduced by permitting the entry of coarse silt
(d) All the above
Q. 184 Side slopes generally kept for canals in loam soil,1 are:
(a) 1 : 1 in cutting and 12 : 1 in filling2
1 (b) 1 2: 1 in cutting and 2 : 1 in filling
(c) Neither (a) nor (b)(d) Both (a) and (b)
Q .185 A counter berm is(a) a horizontal benching provided on the inside
slope(b) a horizontal benching provided on the outside
slope(c) a vertical benching provided on the outer
edge of the bank(d) a vertical benching provided on the inner edge
of the bank
Q, 186 A minimum of 90 cm free board is provided ifthe discharge in the canal is between (a) 30 to 33 cumecs (b) 30 to 60 cumecs (c) Over 60 cumecs (d) Over 100 cumecs
Q.187 The width of a dowfa is generally kept between30 to 60 cm and its height above the road level should invariably be more than(a) 10 cm (b) 20 cm(c) 30 cm (d) 40 cm
Q .188 If L is total length of a canal in kilometres, Pis total perimeter of its lining in metres and C is the cost of lining per square metre, the additional expenditure involved on lining, is
PLC (a) 1000 LPC (b) 1000
PL (c)
100PC
(d) 100L
Q.189 A river training work is generally required whenthe river is (a) aggrading type (b) degrading type(c) meandering type (d) stable type
Q. 190 If A is the area of the surf ace, x is the depth ofits C.G. from the surface of the water and w is the density of water, then (a) total pressure on the surface is equal to wx
(b) depth of the point at which total pressure actsis equal to its moment of inertia divided byAx
(c) depth of the centre of pressure is 2/3 H
vertically below the surface( d) All the above
Q.191 According to Bligh's creep theory, percolatingwater flows along (a) straight path under the foundation of the dam(b) circular path under the foundation of the dam(c) the outline of the base of the foundation of
the dam(d) none of these
Q .192 If the height of the hydraulic gradient line above the floor of thickness tis hand the specific gravity of the material of the floor is G, the minimum thickness t of the floor down stream of the crestwall, is given by the equation
(a) t = h + 1 (b) t = h -1G+t G+1 h-1 h+1 (c) t = G _ 1 (d) t =
G
0.193 If 01 and 02
are depths of w�ter up-stream and down stream of a hydraulic jump, the loss of head at the jump, is
(02-0 i )3
(b) 2O1�
(d) (02 -0,) 401 02
Q .194 If Hand dare the water depth and drop in thJ bed level at a Sarcia fall , the width 8 of thJ trapezoidal crest, is given by
(a) 8=0.22-JH+d (b) B=0.33-JH+d
(c) 8=0.44-JH+d (d) 8=0.55-JH+d
Q.195 In Montague type fall(a) a straight glacis is provided(b) a circular glacis is provided(c) a parabolic glacis is provided(d) no glacis is provided
O.196 To hold hydraulic jumps, baffle wallsprovided in (a) Sarcia type falls(b) English type falls(c) Montague type falls(d) Vertical type falls
0.197 Cross regulators in main canals are provide (a) to regulate water supply in the distributaries(b) to increase water head upstream when a main
canal is running with low supplies(c) to overflow excessive flow water(d) none of these
Q.198 In a canal syphon, the flow is(a) under atmospheric pressure(b) pipe flow(c) with critical velocity(d) under negative pressure
0.199 When a canal and a drainage approach each other at the same level, the structure so provided, is (a) an aqueduct (b) a syphon(c) a level crossing (d) inlet and outlet
0.200 Pick up the correct statement from the following: (a) In a level crossing, a crest with its top at the
canal F.S.L. is provided across the drainageat its up-stream junction with canal
(b) In a level crossing a regulator is providedacross the drainage at its down-stream
(c) In a level crossing , a cross regulator isprovided on the canal below the crossing
(d) All the above
�ciding the alignment of a proposed canal 0-20
1 taking off from a river at 8, three alignments of
proximately equal lengths are available. These
:ass a drainages at C1 • C2 and C3 where
drainage bed levels C1 > C2 > C3, you will provide
at site C3
(a) an aqueduct (b) a syphon aqueduct(c) a super passage (d) a syphon
0_202 The uplift pressure on the roof of an invertedsyphon, is maximum when {a) drain in running dry {b) canal is running dry (c) canal is running with F.S.L.
(d) drain is running with H.F.L.
Q.203 The most suitable location of a canal head work,is (a) boulders stage of the river(b) delta stage of the river(c) rock stage of the river(d) trough stage of the river
Q.204 According to Khosla, the exit gradient of surfaceflow (a) depends upon the bf d ratio(b) is independent of the bid ratio(c) is independent of the depths of dis cut-off
wails(d) none of these
0.205 Meandering of a river generally occurs, in(a) rocky stage (b) delta stage(c) boulder stage (d) trough stage
0.206 A deficit of sediments in flowing water may causea river (a) meandering type (b) aggrading type(c) degrading type (d) sub-critical type
0·207 Trie down stream expansion head of a guide bank is extended to subtend an angle at the centre, equal to (a) ':5J>(c) fJY
(b) 45°
(d) gy
Q.208 Groynes are generally built (a) perpendicular to the bank(b) inclined up stream upto 30°
(c) inclined down stream upto 30°
( d) al I the above
I I I I I I
Q.209 A groyne I(a) contracts a river channel to improve its dept�(b) silts up the area in the vicinity by creating�
slack flow I (c) trains the flow along a certain course I( d) all of the above I
Q.21 O In case of syphon aqueduct, the H.F.L. of the 1
1 drain is I (a) much below the bottom of the canal trough I(b) much higher above the canal bed I (c) in level with the canal bedI (d) none of the aboveI
Q.211 Given that the base period is 100 days and the Iduty of the canal is 1000 hectares per cumecs, Ithe depth of water will be (a) 0.864 cm (b) 8.64 cm(c) 86.4 cm (d) 864 cm
Q.212 Acidic soils are reclaimed by (a) leaching of the soil(b) using limestone as a soil amendment(c) using gypsum as a soil amendment(d) provision of drainage
Q.213 What is the moisture depth available for evapotranspiration in root zone of 1 m depth soil, if dry weight of soil is 1.5 gm/cc, field capacity is 30% and permanent wilting point is 10%? (a) 450 mm (b) 300 mm(c) 200 mm (d) 150 mm
Q.214 If the sensitivity of an irrigation module is 0.5, then what percent variation in outlet discharge will be caused by 50 per cent variation in canal water depth? (a) 100%(c) 25%
(b) 50%(d) 12.5%
Answer�] . .
;�!ri�a��,on_ En,gineering1. (c) 2. (b) 3. (b) 4. (a) 5. (d) 6. (b) 7. (c) 8. (c)
9. (d) 10. (a) 11. (d) 12. (c) 13. (b) 14. (a) 15. (c) 16. (b)
17. (b) 18. (c) 19. (c) 20. (b) 21. (c) 22. (a) 23. (c) 24. (c)
25. (c) 26. (c) 27. (b) 28. (d) 29. (a) 30. (d) 31. (b) 32. (b)
33. (c) 34. (a) 35. (d) 36. (b) 37. (c) 38. (a) 39. (b) 40. (c)
41. (b) 42. (d) 43. (b) 44. (c) 45. (b) 46. (c) 47. (b) 48. (b)
49. (b) 50. (b) 51. (a) 52. (c) 53. (a, b) 54. (c) 55. (a) 56. (d)
57. (a) 58. (d) 59. (a) 60. (c) 61. (b) 62. (a) 63. (a) 64. (b)
65. (a) 66. (c) 67. (b) 68. (c) 69. (b) 70. (a) 71. (d) 72. (a)
73. (c) 74. (c) 75. (c) 76. (b) 77. (d) 78. (b) 79. (b) 80. (c)
81. (d) 82. (d) 83. (b) 84. (c) 85. (b) 86. (c) 87. (b) 88. (a)
89. (b) 90. (d) 91. (b) 92. (d) 93. (b) 94. (a) 95. (a) 96. (c)
97. (b) 98. (d) 99. (a) 100. (a) 101. (b) 102. (b) 103. (a) 104. (d)
105. (b) 106. (b) 107. (b) 108. (c) 109. (c) 110. (b) 111 . (a) 112. (b)
113. (c) 114. (c) 115. (a) 116. (d) 117. (a) 118. (a, b) 119. (b) 120. (c)
121. (a) 122. (c) 123. (c) 124. (c) 125. (b) 126. (b) 127. (b) 128. (a)
129. (b) 130. (c) 131. (a) 132. (b) 133. (b) 134. (c) 135. (a) 136. (b)
137. (a) 138. (a) 139. (a) 140. (c) 141. (a) 142. (c) 143. (c) 144. (c)
145. (b) 146. (a) 147. (a) 148. (d) 149. (b) 150. (a) 151. (c) 152. (c)
153. (a) 154. (c) 155. (a) 156. (c) 157. (c) 158. (d) 159. (b) 160. (a)
161. (c) 162. (b) 163. (a) 164. (c) 165. (a) 166. (a) 167. (a) 168. (b)
169. (d) 170. (c) 171. (b) 172. (b) 173. (a) 174. (d) 175. (b) 176. (d)
177. (a) 178. (d) 179. (d) 180. (d) 181. (d) 182. (d) 183. (d) 184. (d)
185. (b) 186. (c) 187. (c) 188. (a) 189. (c) 190. (d) 191. (c) 192. (c)
193. (d) 194. (d) 195. (c) 196. (b) 197. (b) 198. (b) 199. (c) 200. (d)
201. (a) 202. (d) 203. (cl) 204. (a) 205. (d) 206. (c) 207. (b) 208. (b)
209. (d) 210. (b) 211. (c) 212. (b) 213. (b) 214. (c)
flt (c):1
Iii' Main source of water are sub-surface (Ground)ater and surface (Hydrology) water. Auxiliary
:ater source is sewage disposal etc.
El (b) . . .In gravity 1mgat1on, flow occurs under the gravitybut in lift irrigation some external energy needed to extract the water from the ground like somemechanical device, so it is costlier.
II (bl_
Volumetric method of assessment leads to a lower duty. This is because the farmer will use water economically. Thus (b) is the correct answer.
II iai_KMnO
4 removes both organic matter and micro
organisms from the water, that's make the water odourless . Though it is primarily a disinfectant.
II (d)
S .. . S dq/q ens1t1v1ty = dG/Owhere q = discharge through outlet, dq
= changein discharge through outlet, G = gauge reading, and O = depth of water in distributing channel. Rigid module always maintain constant discharge (i.e., dq = 0). Therefore, sensitivity is zero. Hence (d) is the correct answer.
rJ (b) The common examples of flexible type of modulesare: Pipe outlet, venturi flume (Kennedy's Gaugeoutlet), open flume and orifice semi-module.
El (c)The discharge passing over the ogee spillway isgiven by the equation
0 = C · '-e · rPa12
Where, Le = Effective length of spillway cro5t
C = Coefficient of dischargeH = Total head over the crest including
e the velocity head
He=
Hd + Ha
Ill <c>
( ::)
Hydrodynamic pressure drug
Von-Karman equation P
HO= (0.555)y
w· K· H2
m {d) 't= (cr
v-cr
2)*tana
where, cr2
= y w · h2
So pressure of tail water in a gravity dam decreases the shear stress.
Ill <ai.
Free board help as a safety for unforeseen floods, higher than the designed flood. Pre board and increase in top width will increase the weight that will shift the resultant towards upstream side.
rm (d)The pressure distribution may assumed to be
triangular, of height of ( �hw). Otherwise wave
height may be given as hw
= 0.032M for F> 32 km
m (c) Seepage through embankments in an earthen dam is controlled by drainage filters called 'drains', are generally provided in the form of (a) Rock toe(b) Horizontal blanket(c) Chimney drain
m (b) Shaft spillway is generally used where there is inadequate space for other types of spillways.
m (a) Divide wall is a long masonry or concrete wallconstructed at right angles to the axis of the weir toseparate the undersluices from the rest of the weir.
m {c)
As per Khosla's theory
Exit gradient , G = H. _1_ d n..fi.
d=0G = oo
Ill (b):
For no movement of sediment particles'tc
2: 'to 0.056 y w d( G
s - 1) 2: RS {for stone Gs= 2.05}
d 2: 10.82 RS
d = 11 RS
m (b)
For bed of the canalAverage shear stress= Tractive force per unit areaFor side slopes of the canal average shear stress,
'to= 0.75ywRS For side slopes of the canal average shear stress
'to= 0.75ywRS
m (c) j
Lacey's theory consider the eddies, that supportthe silt suspension, are generated from bottomas well as sides of channel.
m (c)'
As per Lacey's theory, bed slope can becalculated as
t5!3
s = 334001/6
El (b)
It is given by, 4.75JQ = 4.75v'64=38m
Ell cc>_':
Flexibility, (R)=(dq/q)dQ/0
where, q = Discharge through outletQ = Discharge through minor (channel)
If F = 1, then outlet said to be proportional
Sensitivity, S =
dq/q dy/y
S= nF where n is channel indexFor rigid module d
q = 0
S=0
m (c}
Rigid modulus or modular outlets are those which thedischarge is constant end fixed within limits, irrespective of the fluctuations of the water levels ofeither the distributary or of the water course or of both.
m (c)
Tortuosity or sinuosity: Ratio of arcual length(length along the channel) to the direct axial length.
m (c)
Major objective of river training is to prevent theriver from changing it course, protect river banksensure effective disposal of sediment load and improve navigation by providing minimum depth.
El cc>Additional number of rain gauge required
_ ( Coeff. of variation )
2 Existing number- Allowance% of error - of stations
= (��r-4=9-4=5
Em (b)
Syphon Aqueduct:
• HFL of the drain is much higher above thecanal bed (on canal bottom).
• Water runs under syphonic action through theaqueduct barrels.
m (d)
Functions of cross regulator: 1. Effective regulation of the whole canal system.2. Absorbing fluctuations and preventing the
possibilities of breaches in the tail reaches.3. Helps to feed the off taking channels.
m (a):
For the upstream slope of an earth dam, the mostcritical condition is sudden drawdown. In such a case, the water level within the soil willremain as it was when the soil pares were full ofwater. The weight of this water within the soil nowtends to slide the U/S slope along a circular curve.
Id <ci>}liiil· . � The sequent peak algorithm technique hel t . . I ps o device s1mp e mathematical solution to th problem of computing the reservoir capacity.
e
ll(b)] This combined use of subsurface water (groundwater) and the surface water (canal water) in ajudicious manner, as to derive maximum benefits called conjuctive use, should hence be adoptedto control water-logging.
II (b)j When the velocity of flow through a channel is very small, the channel bed does not more at all, and the channel behaves as a rigid boundary channel.
El (d) Irrigation may be defined as the process of artificial application of water to the soil or land for the growth of agricultural crops.
Ill (b)pH value of water should be in range that it should not harm the plants and its productivity. Generally range of pH value should be 6 to 8.5
El <c>Water which cannot be removed by capillarity is not available to the plants, and is called the hygroscopic water.
m (a) Water that is attached to the soil molecules by surface tension against gravitation forces, and can be extracted by plants by capillary. This water is called capillary water.
m (b) The amount of water required to fill up the pore space in soil particles by replacing all air held in pore spaces, is known as saturation capacity.
Difference of field capacity water and permanent wilting point water. This is known as availablemoisture or maximum storage capacity of soil.
11,�, i
The permanent wilting point is that water contentat Which plant can no longer extract sufficient waterfor its growth, and witts up.
111 <b),. '
Difference of field capacity water and permanent wilting point water. This is known as available moisture or maximum storage capacity of soil.
___ (d)_i Water cannot be easily drained under the action of gravity, and is called the 'field capacity'.
El<�)_,, Duty: Number of hectares of land irrigated for full growth of a given crop by supply of 1 m3/sec of water continuously during the entire base period (B) of that crop.
.,.. (c_);lliiiil _,, 'j
Duty of water, therefore, varies from one place to another and increases as one moves downstream from the head of the main canal towards the head of the branches or water courses.
m (b)�
m (c)-
Kharif reason Crop ratio = ----Rabi reason
Duty of water, varies from one place to another, and decreases as one moves upstream from the head of the branches or water courses towards the head of main canal.
Iii (b): When the soil may be too dry to be sown easily, the soil is moistened with, so as to help in sowing of the crops. This is known as "Paleo irrigation".
El (b) (
Extending down from the ground surface, is the soil zone or the root zone, which is defined as being the depth of overburden that is penetrated by the roots of vegetation.
Ill (b)The moist air masses may get lifted upto higher altitudes due to the presence of mountain barriers and consequently undergo cooling, condensation and precipitation. Such a precipitation is known as orographic precipitation.
Dicken's formula is used in the central and northern parts of the country
Op = Co· A3l4 Op = Maximum flood discharge (m3/s) A = Catchment area (km2)
C0 = Dicken's constant with value between 6 to 30
Inglish formula is based on flood data of catchments in Western Ghats in Maharastra.
El<�>_
Q 124A {A = Area (km2)}p =
JA+10.4
A unit hydrograph is defined as the hydrograph of direct run-off resulting from one unit depth (1 cm) of rainfall excess occurring uniformly over the basin and at a uniform rate for a specified duration (Ohours).
m {a,b).
If the earthwork in excavation equals the earthwork in filling. Such a thing in possible when a canal is constructed partly in filling and partly in cutting, which mostly happens in practical life.
m {c).Garret's diagrams are based on the Kennedy's method are are used for design of irrigation channels.
El<a> Critical velocity ( V
0) in a channel can be defined as
the mean velocity (across the section) which will just keep the channel free from silting or scouring.
• {d)_
V0
= 0.55 m d0 ·64 d = Depth of water in channel (m)
m = Critical velocity ratio
In Lacey theory, silt supporting power of a channelis proportional to the wetted perimeter of thechannel and not to its width as was presumed byKennedy.
El ca>_ In Lacey's theory
Silt factor (f) = 1.7B.Jdmm d = Average particle size (mm) rrm
--(d}·
A cross regulator is provided on the main canal ( or the parent canal) at the down stream of the Off take to head up the water level and enable the off taking channel to draw the required supply.
El ca1� The glacis type of falls are mainly of two types: (i) Straight glacis type. (ii) Parabolic glacis type (Montague type falls).
m (C)•Types of rigid modulus: (i) Gibb's module(ii) Khanna's rigid module(iii) Foote module
Ell (b)
m (a)·
S .. ·t dq/qens1t1v1 y = dy I y
q ➔ Discharge throughy➔Water
Bligh's creep theory assume that the water percolating through sub-surface condition creeps along the base profile of the impervious floor.
m <�>_,In Lane's weighted creep theory. It is considered that horizontal creep is less effective in reducing uplift than the vertical creep, and it is proposed a
weighage factor of ( i,) for the horizontal creep
as per his observation, again a factor of 1 for the vertical creep.
m (b)-When a stream of water moving with a high velocity and low depth (i.e. supercritical flow) strikes another stream of water moving with a low velocity and high depth (i.e. sub-critical flow), a sudden rise in the surface of the farmer takes place. This phenomenon is called hydraulic jump.
m (_a),The short straight reaches of the river, connecting two consecutive clockwise and anti-clockwiseloops, are called crossings or cross-over.
�:
�).
The rate at which water 1s removed by a drain iscalled drainage. It is expressed as the depth ofwater in cm or metres, to be removed in 24 hoursfrom the drainage area.
rl<b)
The various available types of outlets (modules)are: (i) Non-modular outlets are those through which
the discharge depends upon the differenceof head between distributary and watercourse. Common examples are open sluiceand drowned pipe outlet.
(ii) Semi modules or flexible modules are thosethrough which the discharge is independentof the water level of the water course butdepends only upon the water level of thedistributary so long as a minimum workinghead is available. Common examples are pipeoutlet. venturi flume, open flume and orificesemi-module.
(iii) Rigid modules or modular outlets are thosethrough which the discharge is constant andfixed within l imits, irrespective of thefluctuations of the water levels of either thedistributary or of the water course or of both.Common example is Gibb's module.
El<c> The annual intensity of irrigation is the sum total of intensities of irrigation of all the seasons of the year. Intensity of irrigation for kharif season
= 100- 76 = 24% Intensity of irrigation for rabi season
= 100 - 58 = 42% :. Annual intensity of irrigation
= 24 + 42 = 66%
a (b)
SAR = Sodium Absorption Ratio
m (a)
Total water applied = 8 X 3600 X 6 = 172800 m3
Height of water applied Volume of water
=------Area
= 172800 = 0.432 m40x104
= 43.2 cm Field application efficiency
m (d)
= �x100 = 70% 43.2
Crop consumptive water use is the amount of water transpired during plant growth plus what evaporates from the soil surface and fatigue in the crop area.
Ill <a>
Water mainly used by plants is from capillary water. CIR (consumption irrigation requirement) = Cu
- Pett
Cu= Consumptive use or evapotranspiration.
From definition of CIR, it is clear that, the portion of evapotranspiration to be satisfied by irrigation is called CIR. Hygroscopic water is water below P.W.P. Yield of crop increases only upto optimum depth, beyond that yield starts reducing.
m (c).
Lacey's silt factor, f = 1.76Jd: = 1.76x ✓0.16 = 0.704
m c�,Lacey's silt factor
f = 1.76Jd:
dm = ( 1_;6r = 1.3
m (C)I
Maximum tractive shear stress on the sides and on the bed of a channel is 0. 75 y y0
s0
and 0.97y Yo8arespectively.
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.,. (b"' IMillJ-.A rigid bed canal has one degree of freedom Le.for a given channel a change in discharge wouldcause a change in the depth only,A man-made alluvial channel has three degreesof freedom i.e. for a given channel, change indischarge can cause changes in width, depth andbed slope. Thus three equations independent ofeach other are needed, as given by Lacey, torepresent three degrees of freedom viz. depth,width and gradient. A natural alluvial river has fourdegrees of freedom as its planform can also alter.
Iii (d);Balanced depth of cutting of canal is where volume of cutting = volume of filling. This reduces the transportation expenses of soil.
IZl<b) The ratio of depth of water level over crest on the downstream of the module (H
2) to the depth of
water level over crest on the upstream of the module (H
1) is called drowning ratio or
submergence ratio (HJH1).
The rate of change of discharge through the outlet to the rate of change of water level of the distributary or channel is called sensitivity. The rate of change of discharge of outlet to that of distributary is called flexibility. Modular limits are extreme values of any one or more variables, beyond which an outlet becomes incapable of acting as a module or semi-module. The range between the lowest and highest limiting values of various such factors is known as modular range.
� (b); -- Ii
When the available natural ground slope is steeper than the designed bed slope of the channel, the difference is adjusted by constructing canal falls or drops. The location of fall depends upon the topography, command area and the possibility of combining it with a bridge, regulator, or some other masonry work, since such combinations often result in economy and better regulation.
m· ..+<d>r
Garret's diagram gives the graphical method of
designing a channel. Basic aim is to save time. It is
based on Kennedy's theorem and Kutter's formula.
Average shear stress ac.1ing on bed of channel at wt,ich sediment particles just begin to move is called Critical shear stress. Increase in plasticity index at given void ratio increases cohesion. thus incr6ases the Critical shear stress. Increase in shP.,ar strength increases the Critical shear stress. As void ratio decreases for given Plasticity index, Critical shear stress increases.
m(b,
5 v2 Hydraulic mean radius = R = - . -
2 f
v = mean velocity = 1 . 1 m/s f = silt factor = 1 . 1
R = § x 1· f = 2. 75 m
2 1.1
Note: None of these answer is correct, but nearest answer is 2.27 m.
m (c)Impounding reservoirs can store water during high flow and utilize the same during lean flow period (i.e. when flow in stream is less than demands}.
El<b) H
b = Jp from stress criterion
H b = µp from stability or sliding criterion
m (c)
Arch dams are solid walls curved in plan. They behave as a cantilever retaining wall standing up from its base, and partly the load will be transferred to the two ends of the arch span by horizontal action. In the trial load method of design, the load is assumed to be distributed between the arch elements and the cantilever elements. The deflection calculated at conjugal points should be the same.
- (b)·
Arch dams can be divided into three types: (i) Constant radius arch dams(ii) Variable radius arch dams(iii) Constant angle arch dams
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�ant radius arch dam is simplest in designan
d construction, but uses the maximum concrete.A constant angle arch dam uses about 43% ofconcrete used by constant radius arch dam. Avariable radius arch dam is an intermediate choice using around 58% of the concrete used b; constant radius arch dam.
__ (a) Check dam is used for flood control.
II (b) For elementary profile
B= H ✓Sc -e
When uplift is ignored C = O
B= H
Js;
cr H= 25x.J2.56=40m
a,c0, 'nen the vertical acceleration is acting downward, · ·oundation will try to move downward, i.e. away· om the body of the dam; thus reducing thee .. ec ive weight and stability of the dam. Thus itme ,orst case from design point of view. When
the eservoir is full, the force due to horizontal acceleration would produce worst results if it is ad.di i,1e to the hydrostatic water pressure, thus acting tc,1,iards the downstream. When the reservoir
�pty, his force would produce worst result, if 'X'flsidered acting upstream.
11., Cv Stant Center Arch Dam (variable angle) have the following feature . • • Gooo for U.-shaped valley • Easy construe;tion• Vertical upstream face• Appropriate for middle-high dam
II (cl)
Spacing of the drains S == 4
K ( tl - ti)q
'M'lere
K is coefficient of permeability q is discharge per unit length in the drain
a is depth of impervious strata below the drain b is maximum height of the drained water table above the impervious layer.
m(,b).
When tail water curve coincides with jump rating curve no extra construction cost is required to dissipate energy or to protect the basin as it is ideal condition tor energy dissipation in design of spillways. When the tail water-rating curve coincides with jump curve for all values of discharge then the requirement for the sequent, depths are always satisfied and the jump forms at the same location.
Discharge
m (a)
Leaching is the process in which land is flooded with adequate depth of water. The alkali salts present in soil, get dissolved with this water, which perqolate down to join the water table or are drained away by sub-surface drains.
Leaching requirement , LR= Od D;
D dis Depth of water drained out per unit area D; is Depth of irrigation water applied per unit area
Di = ell+ 0
ri
e11
is Consumptive use
LR = 0., - q1 = EC,.
o,. ECd
Ci is Electrical conductivity of irrigation water
EC,, is Electrical conductivity of drained water.
El<•>
Downstream sheet pile is provided to reduce high value of exit gradient. It increases the seepagepath and reduces head in the end.
Outlet index for orifice type outlet = ..!.2
. 5Channel index = 3
Setting= Outlet index
= 1/2 = 0_3Channel index 5/3
El(b>
m<d)
H 1 GE= dx n.fi.
A= 1+� =2
1+� =2.562
( .. a = b = 20 = 4) . d 5
5 1 1GE = 5 X
3.15 X ✓2.56 = 5
Check dam and contour bunding are mainly waterharvesting techniques. Contour bunding cancheck erosion in hilly areas but it is not veryeconomical as every year the bunds are to bemaintained before rainy season. The afforestationof catchment area is the long lasting andeconomic solution for soil conservation.
El<a> During floods river carries silt charge in excess ofthe quantity required for stability, the river startsbuilding up its slope by depositing the silt on itsbed. This accretion is the primary process, whichconsequently leads to meandering. The increasein slope tends to increase the width of the channeland the sediment carrying capacity decreases. Finally due to shifting of the convex bar, the widthbetween the banks reduces, which increases thevelocity and sediment carrying capacity also.
&<a) Gibb's module is a rigid module or modular outletand the discharge through it is constant withincertain limits, irrespective of the fluctuations ofwater level in distributary or water course or both.
•-(b)
The difference in bed level of the canal anddrainage is 4 m while the flow depth in drainageis 1 Om. Thus HFL of drain at 126 m is higher thanthe canal bed at 120 m. Therefore syphon aqueductis most suitable.
lm<b) Silt excluders are constructed on the bed of theriver, upstream of the head regulator. While siltejectors are constructed on the bed of the canaland a little distance downstream from the headregulator. Silt excluders remove silt from the water before itenters canal. Silt ejectors extract the silt from thecanal water after the silted water has travelled acertain distance in the off-take canal.
mJ (a)
Syphon aqueduct is a cross-drainage workprovided when HFL of the drain is higher than thecanal bed and the water passes through thesyphon aqueduct (drainage) barrels undersyphonic action. The worst condition of uplift willbe when the drainage is flowing at HFL and canalis dry.
m (d) Denehy's T-shaped groyne is a special type ofgroyne developed in India for protection of bank.It comprises of ordinary groyne with an extracross groyne at the head giving it T-shape. Hockey shaped groyne is an attracting type ofgroyne.
Im (b). A groyne pointing downstream has the propertyof attracting the flow towards it and is called anattracting groyne. In attracting groynes scoursholes are developed nearer the bank, as comparedto those in a repelling groyne. Since such attractinggroynes bring the water current as well as scourholes nearer the bank and make it more susceptibleto damage, they are not used generally. Thegroynes are therefore, generally aligned eitherperpendicular to the bank or pointing upstream(repelling groyne).
,:
IOikt V = 0.55 m QD .64 (Kennedy's) V = (1/n) R213 s112 (Manning's)V = 10.8 R213 s113 (Lacey's)
II �b)�
Non-modular outlets are those through which thedischarge depends upon the difference of headbetween the distributary and the water course. Thedischarge through such a module, therefore,varies widely with either a change in the waterlevel of the distributary or that of the water course.The common examples of this type of outlets are(i) open sluice and (ii) drowned pipe outlet.
m (c). For orifice type outlet,
C!:J (c) -
1m=2
H Setting= -D
1 3 3 = -x-= - = 0.32 5 10
Gravity water -Superfluous waterHygroscopic water-Available waterCapillary water - Water stored due to capillaryaction
am (b)
Free Flooding method may be used on rolling land(topography irregular) where borders, checks,basins and furrows are not feasible.
DD <a>Intensity of irrigation: The percentage ofCulturable Command Area (CCA) proposed to be. . . on ·Ic- called the intensity irrigated in a given seas .., of irrigation of that season.
DD (b). . t ·s defined as theField irrigation requIremen 1
amount of water required to meet the net irrigation. . 1· ation losses duerequirements plus the field app ic
to surface runoff and deep percolation.
1111 {c) :
. ( Arcual length )Sinuosity or Tortuosity = . . 1 1 th Direct ax1a eng
Im {c)_,
In a submerged weir both water level at upstreamand downstream are above the crest level of theweir.
mJ _{a):
Lining of canals reduces the seepage of water,thus it decreases the waterlogging of an area. Itincreases hydraulic efficiency and resistance toerosion.
m {d),
River training is to guide and confine the flow tothe river channel, and to control and regulate theriver bed configuration, thus ensuring safe andeffective disposal of floods and sediment loads.
ma {a).�
Refer clause 8.2 of IS 10430: 2000Minimum free board for various canal dischargesare:
Canal discharge Minimum free board (cumec) (m)
> 10 0.75
3 to 10 0.6
1 to 3 0.5
<1 0.3
m {a,b>'_
Permanent/Perennial canal-These are the canalswhich get continuous supplies by permanentsource of supply like a river or reservoir. Theseirrigate the field throughout the year with equitablerate of flow.
rm {b)
Inundation canal are long canals taken off fromlarge rivers. They receive water when the river ishigh enough and especially when in flood.
mJ (c)Surcharge storage is the storage between the fullreservoir level (FRL) and the maximum water level(MWL) of a reservoir.
Im (a)·Berms or horizontal strips of land provided at canal banks in deep cutting. The berms serve as a road for inspection vehicles and also help to absorb any soil or rock that may drop from the cut-face ofsoil or rock of the excavations.
mJ (c).
Hydraulic radius (R) =
Area (A) Wetted perirreter (P)
ml (c)
Sensitivity is defined as the ratio of the rate of change of discharge through the outlet to the rate of change of water level of the distributary, referred to the normal depth of the channel. For rigid modules, the discharge is fixed and hence sensitivity is zero. Hence option (c) is correct.
a (c) As per Lacey's theory, velocity of flow in channel is given by
- [Qf2
]1/6
V- 140
where Q = Discharge of channel (m3/s) f = Lacey's silt factor
Here, 0 = 70 m3/s f = ✓
2
V = I 70 x ( ✓2
)2 1,,s
= 1 .0 m/sl 140
Hence option ( c) is correct.
Im (b}Volumetric method of assessment leads to lower duty.
m (b)_
Silt concentration
The silt concentration in a channel carrying silt load is higher in bottom and relatively less inupper layers. Hence option (b) is correct.
ma {b)
The thickness of concrete lining in canals depends upon: (i) Canal capacity(ii) Nature of canal(iii) Special requirement of imperviousness(iv) Structural strength to resist cracking on slight
movement of subgrade (v) Slope of bank of canalHence all option (a}, (b}, (c) and (d} are correctbut option (b} is most important criteria. Soanswer should be option (b).
mJ (a)
Hydrodynamic pressure effect: It is the pressure force exerted by water on the dam due to seismic activities.
e••· :• . : . ◄-.
Parabolic----:;�=:::!} ?J: ,__ __ _, .. ◄·· .. ...
H 2
•. ,-. : :�·:· ·_.: .
0.55 kywH . -: -><} .• <:':
� :=::::::-.::-..::-_-_-_�..i)t :// i/? /.:, ;; /:<?\}.ff
k = Seismic coefficient
m (b)
Filter
B' 14--0-.J
It is clear from the figure that the starting point of top parabola (i.e., phreatic line) C is located 0.3 L away from the cutting edge. Where L is the horizontal projection of upstream slope laying below water surface i.e. AB.
(
eoncrete pear -+-+-+-1
- - . - . - -----·-------·-·- - - . - .
---:-� .---_ - .
..
�;�r fa_�-,g�:fe : .. .. = . .
�=�::?2t�·-1i it1 fJ f.;� : � �=l;�=f;t�t tr; :• : 1 (\C.}/ �
Radial Gate
TRUNNION ORPIN
In radial gate, water face segment is made concentric to the supporting pins so that the entire water thrust passes through the pin. Hence the lifting force is required only against the weight of the gate. Hence radial gate can be operated with minimum operating hoisting mechanism. For small work it can be manually operated. Hence option ( c) is correct.
ml (af'
(i) Side channel spillway: This type ofspillway is provided in narrow valley whereno side f lanks of sufficient width toaccommodate a chute spillway areavailable.
(ii) Ogee spillway: Ogee spillway can be easilyused on valleys where the width of the riveris sufficient to provide the required crestlength.
(iii) Chute spillway: Chute spillway is used in
earthen and rock fill dams as a separate
spillway is generally constructed in a flank
or a saddle away from the main valley.
Chute spillway is also used when main
valley is narrow. But mainly side channel
spillway is preferred in narrow valley.
(iv) Syphon spillway: When the valley is very
narrow and no space is available for
constructing separate spillway (side
channel or chute spillway) then the syphon
pipe can be installed within the dam body.
In given case valley is narrow but have sufficient
space to construct side channel spillway. Hence the most suitable type of spillway is sidechannel spillway.
rm (b).
In relatively flat land areas (plain area) it is often necessary and advantageous to align irrigation canals along the watersheds (ridge lines) to irrigate the nearby areas. Whereas in hilly areas, ordinary canals are aligned along the contour line.
Im (b)_
The elementary profile of a dam, subjected to the external water pressure on the upstream side, will be a right angled triangle having zero width at the water level and a base width (B) at bottom. In other words the shape of such profile is similar to the shape of the hydrostatic pressure distribution.
r-----i ·· ------_---- ;�:_. Elemerna,y profile
!__ ________ � :::=:::(i{'.Il{i:;
f
;g,ravl,YT:
m
p=ywH
CywH U = Uplift pressure
I• s -1
Hence option (b) is correct.
mJ (c)_�
An outlet is said to be proportional if the flexibility is equals to unity.
or
The outlet is said to be proportional when the rate of change of outlet discharge equals the rate of change of channel discharge. Hence option ( c) is correct.
m (a}
Refer sol. of Q.No. 5, when the irrigation canal is constructed over a drainage the crossing may be (i) Aqueduct: When HFL of drain is far below
the bottom of canal. (ii) Syphon Aqueduct: When HFL of drain is
above the bottom of canal.Here, no information is provided about the HFL of drain, then we can assume HFL of drain is far below the bottom of canal. Hence crossing is called Aqueduct.
Hydrodynamic pressure effect: It is the pressure force exerted by water on the dam due to seismic activities.
.-----:::,:::--------,,1·/� ·'T �_.�� -::.
Parabolic-_i!£.:::::.=::i./ (· (----- •·: ... :,:-:: ◄.•.
H O.S5 .,..,,
� �-=---=-----_-_-�-.1.i!{ lilt {tk = Seismic coefficient
; a,,
a<�>, The undermining (piping) of the floor starts from the downstream end of the down stream pucca floor and if not checked, it travels upstream towards the weir wall.
..... ----=::,-------, �-- � :: _·_ :: � � � ::_ � ::_·_: ◄-·· - - . ----- --. - --.. --.. - - ...... ----------------------· 'IC'
-------·--··-------·--· ....... --- -.. -.. -.. - .. - .. --- - .. ·-; � ·. � j . ►• ' • ► •. '. •, .
undermining
The undermining starts only when the exit gradient is unsafe for the subsoil on which the weir is founded. It is absolutely necessary to have reasonably deep vertical cut off at the downstream end of downstream pucca floor to prevent undermining.
m (a)
Ogee spillway is least suitable for earthen dam because it constructed within the dam body. Earthen dams are most prone to erosion.
Im (a)'.
Generally width of launching apron is equal to 1.50.
where O = scour depth below the original bed.
Hence option (a) is correct.
m (c):
As per Lacey's theory
Scour depth, 0 = 1.35 cf ( ·
)
1/3
where q = discharge per unit width f = silt factor
Im (a),
Wave pressure:
].h 8 w 2.4 'fwhw
1-h .· .... -. Ll�s 3 w. --r- ____ \l __ 7,------ ----- ··�-}.J ------r 3 hw
-=: 'f ·· ... �_. I . ... :• . .
still water level ·. •:. -�-: :-.
,�l ::�\ .. '. .� ...... Max. wave pressure,
1 5 F= 2
x3
hw x2.4ywhw
=> F = 2v h 2 'w w
This F force acts at a distance �hw above still 8
water level. Hence option (a) is correct.
DD <c>Consumptive use of water is the depth of water consumed in evaporation and transpiration during the growth of plants. C = loss of water due to transpiration + loss of
u
water due to evaporation. Hence option ( c) is correct.
mJ (c)
The minimum base width of elementary profile can be obtain from following two criteria.
(I) 8 � �l( G _ C) (stability against sliding)
(II) B � k (Stability against tensile failure)
H == depth of water upstreamG == Specific weight of dam materialµ == Coefficient of frictionc == uplift coefficient
If uplift pressure is neglected i.e., c = oH H
B>- and -- µG JG
Hence option ( c) is correct.
mJ (c)S.N. Classification
1. Saline soil or white alkali2. Alkaline soil or non-saline alkali
or sodic soil or black alkali3. Saline-alkali soilHence option ( c) is correct.
Im (b)
PH value
�8.5
8.5- 10.0<8.5
The upstream face of dam is 100% equipotentialline because at U/S face there is no head loss.
IC (a)Soil moisture tension is the pressure which mustbe exerted on the soil in order to extract waterfrom it. It is a measure of tenacity with which the water isheld by the soil. I t is also known as capillarypotential. At field capacity moisture tension. is about
1 � to -i atm. At permanent wilting point moisture
tension is 7-32 atm. Moisture equivalent of thesoil is the percentage of moisture retained in aninitially saturated sample of soil, 1 cm thick, afterit has been subjected to centrifugal force of 1000times gravity for a period of 30 minutes. Optimum moisture content is slightly less thanfield capacity. S o moisture tension isapproximately same.
ma (a)Kennedy assumed in his silt theory that the siltsupporting power of a canal depends mainly onthe eddies generated from the bed of channel. Hence option (a) is correct.
m (d)
Garret diagram gives the graphical met'1od cfdesigning an irrigation channel based upon"Kennedy's theory".
Im (b)
The first watering after sowing the crop when thecop is few centimeter height, known as korwatering.This irrigation depth is maximum of aHthe watering depth and is called kor depth.The period during which kor watering is appliedfrom the instant of sowing the crop is ca!!ed korperiod.Hence option (b) is correct.
m (a)'
A side slope canal is that which is aligned at rightangles to the contours; i.e., along the side slopesas shown in figure. Since such a channel runsparallel to the natural drainage flow, it usually doesnot intercept drainage channels.Example:
E 0 0 f-- -f-----, ;? E
0 ID Ol
E 0 0 Ol
side slope canal
Ground contours
Alignment of side slope canal
Hence option (a) is correct.
Im (c)
A cylinder/syphon well drop type falls are veryuseful and economic for high drops and lowdischarge.Hence option (c) is correct.
IJD (c)
Depth of open well is normally between 20-30 m.
mJ (a).
Hydrodynamic pressure effect: It is the pressureforce exerted by water on the dam due to seismicactivities
Hence option (a) is correct.
mJ (c):
According to Khos!a theory, exit grac·e ca becalculated as,
G ( . d. H 1 e exit gra 1ent) = d r.Th/I.
.. - - -. - -..... - - - . . . - .... H:::::::::::::::: /: .. �. :> . ! . . . . . . . . . . . . . . . . . . . . ... -.. - . -... - -. . . . . �-. .
: . :_:. . � - - . - - -..... - - - - - ,, � .. . : .
d
----- b -----.
1+.J1+a2 b where )., = ---- and a = -' 2 d
when cut off is zero i.e., d = 0H 1
Ge
= -
r:.- = oo
0 TC✓A Hence option (c) is correct.
rm (a) I
Sensitivity is defined as the ratio of the rate ofchange of discharge through the out:et to the rateof change of water !eve! of the distrlbuta')', ref erredto the normal depth of the channel. For rig:dmodule, the discharge is fixed and hencesensitivity is zero. Hence option (a) is correct.
ID<�>--� An outlet is said to be proportional if the fiexibiHtyis equals to unity.
The OU";et :s said to b€ p:-�or,a; when t.t)e rateat c.h�ge ct ouL' -• C:SC.'ia:ge �:s the rate ofd'.a.'1g€ at d'.a..'"lf"e c '"'"1a:ge.hence �:.-co ( c j .s cone.ct.
Em (c)
The �.e:-:�f ~ '-e o a oz . s...b;ected to thee.1:er ' 1.a:e: press..;:e �t1e · .'S s:de ,,.-ai!, w,llb€ a, :---:: .r.g.ec :.r· �,e '1.a •• .g zero d:h at thewa'.e: · .e a.:- a base .... -c:., ( B) at bottom. In
--,
·h p o: · e in s,m:iar to: pressure drs!rrbut!On.
. .-·- .... ...... ----•.----- ......
I H
!. ·-·. -- yji
B---
ml (b)
Silt ejector or silt extractor: These are the•.� extra'(:;• s.,!� from e canal water
a!'er he s: 1:ed ,ate ,as ra ,el!ed a certainc:s:a:1ce. .ese a�e co ,st ucted on the bed ofca�: a. d ·i:i'e d tar"e d·'S he head regulator.
cheadr�
i ' i
i I -U.-S I i. .
I i-; __ jf
c. ;:.c = c o c o-:-1o :: c o ,:, o c o
c -:. ..-:. c c c o o oo c--:·:.c o o o
c :.c O O,':)C O c :.-� s c o c o
C C � C C � 0 C 0 :: ::: C C C O C 0
C = C = = C C C 0
Hence o;:;t.:,-,n (b) :s correct.
m (a)
In re;ative;y :-:a, :and areas (piain areas) it is oftenr.ecessa� a:id ad antageous to align irrigationca�!s a!ong the watersheds (ridge iine) to irrigatethe nearby areas. Hence option (a) is correct.
Hence option (a) is correct.
IBl<c> According to Khosla theory, exit gradient can be calculated as,
Ge(exit gradient) = � n1
. ·;e·: �-:,.
d
l ----b----
1+✓1+a2 b
where, 11, = ---- and a = -2 d
when cut off is zero i.e., d = O H 1
G - ---=oo
e - 0 nJi
Hence option ( c) is correct.
Im (a)
Sensitivity is defined as the ratio of the rate of change of discharge through the outlet to the rate of change of water level of the distributary, referred to the normal depth of the channel. For rigid module, the discharge is fixed and hence sensitivity is zero. Hence option (a) is correct.
&<c) An outlet is said to be proportional if the flexibility
is equals to unity.
of change of outlet discharge equals the rate of change of channel discharge. Hence option (c) is correct.
111 <c>The elementary profile of a dam, subjected to the external water pressure on the U/S side wall, will be a right angled triangle having zero width at the water level and a base width (8) at bottom. In other words the shape of such profile in similar to the shape of the hydrostatic pressure distribution.
Elementary profile of gravity dam
j_ ______ Yw: [:_::-_-_-.--_ _,----h-. "-r'-lc'"i-'"'.r'.-'r"r-rr7?'1, Toe
m (b)
I
I
I
I
I
I
U = Uplibt pressu�e
--- 8---.i
Elementary profile of gravity dam
Silt ejector or silt extractor: These are the devices which extract the silt from the canal water after the silted water has travelled a certain distance. These are constructed on the bed of canal and little distance d/S the head regulator.
' head regulat or
• 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0
o o o o o o o o...,.
_
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
- UIS 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 O
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 O
0 0 0 0 0 0 O O 0
0 0 0 0 0 0 0 O
0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
Hence option (b) is correct.
m (a)
In relatively flat land areas (plain areas) it is often necessary and advantageous to align irrigation canals along the watersheds (ridge line) to irrigate the nearby areas. Hence option (a) is correct.
The outlet is said to be proportional when the rate
tli�t
_,
J,,
',,, ';1 •'
-(c) .. favorable conditions for sprinkler method: (i) When land topograph is irregular and hence
in those surfaces irrigation is unsuitab/ e,sosprinkler method is adopted.
(ii) When soil is erodible and land gradient issteeper.
(iii) When water table is high. So to prevent waterlogging sprinkler method is adopted.
(iv) When soil is either excessively permeable orhighly impermeable.
(v) When water is available with difficulty and isscarce.
In given statements. statement (1) is wrong, asthis method does not required preparation of /andbefore irrigation. Statement (2) is also wrong it prevent water loggingand provide optimum irrigation.Only statement (3) and (4) is correct.
mJ <t>l-
As strong wind are dominant, sprinkler irrigationmethod can not be used. So the best method isdrip irrigation it is used where there exists scarcityof irrigation water. In this method water is slowlyand directly applied to the root zone of the plant.Hence option (b) is correct.
m (a}
Contour canals are used in hilly areas and it canirrigate only on one side.Hence option (a) is correct.
rm (c}
Given, Q = 3600 m3/s According to Lacey's theory the wetted perimeterof channel
P = 4.75Ja
P = 4.75✓3600===> p = 4.75 X 60
===> P = 285 mHence option ( c) is correct.
l?a (a)
Rivers in flood plains can be classified as:
(i) Aggrading (ii) Degrading
/ /
(v) Deltaic(iv) Braided
Generally most of the food plains river are siltingrivers, such a river increase its bed slope, siltingrivers are also known as aggrading river.Hence most appropriate option is (a).
m (a}:
Spur is a rigid hydraulic structure made normal tothe bank of river or canal to interrupts water flowalong desired direction in order to protect the bankof river or canal.
Bank of river Bank of river
Hence option (a) is correct.
ma (a}
The critical salt concentration in the irrigation waterdepends upon many factors, yet however,amounts in excess of 700 ppm are harmful to someplants but more than 2000 ppm are injurious to allcrops.So the salt concentration in irrigation water shouldnot exceed 2000 ppm.Hence option (a) is correct.
m (b}
Water application efficiency (Tla)
Tla =
Quality of water stored in theroot zone of the plants ( W
5)
Quantity of water divertedto the fields ( lt½)
If includes losses such as run-off from the fieldand deep percolation.
Im {d).
Infiltration capacity: The maximum rate at whicha given soil at a given time can absorb water isdefined as the infiltration capacity.
m (c)
Optimum number of stations = H = (;)2
(iii) stable
lm<b)·: Storage between the minimum pool level and normal pool level is the useful storage in the reservoir.
l!!I .. ··· •.••.,
IMiiil (a).:
Total sediment deposited . . in the reservoir Trap efficiency = T I d' fl .
ota se 1ment owing in the river
IJZ! (d)_,
Uplift pressure on a dam can be controlled by increasing the length of sub-base, providing vertical cut-off, drainage gallery, and grouting in foundation.
Im (b)� Check is filled with water at a high rate and allowed to stand until the water infiltrates.
Im <ci>'. Furrows are narrow field ditches, excavated between rows of plants and carry irrigation water through them.
l!'!I (;)' IYQ .l
A canal aligned on the watershed saves the cost of construction of cross-drainage works.
ml (d). Culturable area is the cultivable part of the gross command area and includes all land of Gross Command Area (GCA) on which cultivation is possible. It will, thus, include pasture and fallow lands which can be made cultivable.
mJ (d) A catchment area is separated from its neighbouring areas by a ridge called "divide".
m (d) The channel losses can be determined by using empirical formulae
!lO = -1-(B + y)213 (Generally used in U.P.)200
m (d). A channel is said to be in a state of 'Regime' if the flow is such that 'Silting and Scouring' needno special attention.
llD (d)-lf there is no resistance from the sides, and all the variables such a perimeter, depth, slope etc are equally free to vary and finally get adjusted according to discharge and silt grade, then the channel is said to have achieved permanent stability, called final regime.
IID (d). Finally bed slope Sis determined by the equation as per Lacey's theory
s � [33::�," l where, f = Silt factor
Q = Discharge (m3/s)
IC! (d) A comparatively steeper slope can be provided in cutting rather than filling, as the soil in the former case shall be more stable.
1 H : 1 V to 12 H: 1 V slope in cutting. 2
12 H: 1 V to 2 H : 1 V slope in filling. 2
Im (b) Berm is the horizontal distance left at ground level between the toe of the bank and the top edge of cutting.
m (c)j Values of free boards in canals:
Discharge (cumecs) Extent of freeboard (cm)
1 to 5 50cm
5 to 10 60cm
10 to 30 75cm
30 to 150 90cm
ma<�>.Dowlas: As a measure of safety in driving dowlas 0.3 m high and 0.3 to 0.6 m wide at top, with side
slopes of 12 : 1 to 2 : 1, are provided along the2 banks.
m (a)·_ Total length = L (km)
Total perimeter = P(m)
cost of lining per square meter c Expenditure = (1000 L) * (P) * C= 1000 LPG
- (�)'] .. River tra1n1ng works are constructed f or severalreasons but the fundamental obi·ective 1·s t . o re�cthorizontal movement of the river channel 1 . . a ong acertain allgnment.
II (d).
-r-
l ---·
____ ....... ----
Total pressure = w. xh _ IG . 2 = X +-·Sin 0
Ax For rectangular surface
Centre of pressure= ( �H) from the surface.
Im (c).
According to Bligh's creep theory, percolatingwater flows along base profile of impervious floor.
mJ (c).
'
I
h /,/
/_
/_/---------------
Top ·-----tj ,, Bottom --- --�'-------'
h = ( H -1 * Lp) = Ordinated of hydraulic
gradient line measured above the top of floor.
ID (d)
Loss of head at the jump6.E = E1 - E2
· (Y2 - Y1)3 _ (� - 0i
= 4Y1Y2 - 40i�
a (d)_·
For O < 14 cumec Top width (Trapezoidal section)= 0.55J°dFor O > 14 cumec Top width (Trapezoidal section)= 0.55.JH + d
Im!�>.� An improvement in energy dissipation may bebrought about montague type of fall by replacingthe straight glacis by a parabolic glacis.
m {b)�
A straight glacis type fall when added with a Baffleplatform and a Baffle Wall was developed byEnglish and is call "English Fall" or "Baffle Fall".
Im (b)
Cross rectangular is provided on the main canal( or the parent canal) at the downstream of the offtake to head up the water level and enable the offtaking channel to draw the required supply.
mJ <b) ..
Canal Syphon: • FSL of the canal is much above the bed level
of drainage trough.• Canal runs under syphonic action under the
stream trough.
mJ (c).; Level crossing is provided when canal and streammeet each other at practically the same level.
m (d)·:
-
Drainage
! Crest -canal
! Regulator
Drainage
Level Crossing
mJ (a)'
Aqueduct: • HFL of the drain is much below the bottom of
the canal. • So, the drainage water flows freely under gravity.
Em <ct):'. Canal runs under syphonic action under the streamtrough, in canal syphon.
Em<d). Trough stage or alluvial stage:• The cross section of the river is made of sand
and silt. • The bed slopes are small and velocities are gentle.
m (a)· As per Khosla's theory,
H 1GE =
d. n-5.
m (d)
A= 1+�2
band )., = d
River in Alluvial Flood Plains (Lower Reaches):
The chief characteristics of these river reaches is thezig-zag fashion in which they flow, called meandering.
m (c}_If the river bed is constantly getting scoured toreduce and dissipate available excess land slope,then the river is known as a degrading river.
m Cb)
El (b)
A
----- 120· -140°
R -�-------- B
R
__ ,.. __ 40" -60°'..1 ·- C \
'
D
Gulde bank
Repelling groyne points towards upstream at an angleof 10° to 30° to the line perpendicular to the bank.
m (d}
Groynes are structure constructed transverse tothe river flow and extent from bank into the riverupto certain limit.
mm (b): In syphon aqueduct HFL of the drain is muchhigher above the canal bed (on canal bottom).
EDI (c}:
ml (b)j
Lix0=864x8 D = 1000 ha/cumecB = 100 days
Li = 864 x 100 = 86.4 cm1000
The salts injurious to the health of plants are alkalisalts eg. Na
2C0
3, Na
2S0
4 and NaCl. Such a salt
affected soil is unproductive and is known as salinesoil. If the soil is saline and the efflorescencecontinues for a long period, then soils become illaerated and highly unproductive and these are calledalkaline soils. These soils can be reclaimed by(i) Leaching (ii) Providing surface and subsurface drainage
of the area. (iii) Crop rotation (iv) Lining of canals and water courses(v) Reducing the intensity of irrigation.(vi) Optimum use of water(vii) Gypsum addition Acidic soils, on the other hand, can be reclaimedby basic salts such as limestone.
Em (b}_,
Moisture depth = yd x (FC- Pv\P) dYw
m! (c)
Sensitivity,
where
= �x(0.3-0.1)x11
= 0.3 m = 300 mm
S = (dq/q)(dy/ y)
q is discharge through outlety is depth in distributary canal.Given, S = 0.5
dq/q =?
dq = dy x S = 50 x 0.5 = 25%q y
