List Of Objective Questions On Irrigation Water Resources Part – 2
1.The sensitivity of a rigid module is
zero
between zero and one
1
infinity
ANSWER : : zero
2.In a Sarda type fall, rectangular crest is used for discharge upto
6 cumecs
10 cumecs
14 cumecs
20 cumecs
ANSWER : : 14 cumecs
3.If D is the depth of scour below original bed, then the width of launching apron is generally taken as
1.2 D
1.5 D
2.0 D
2.5 D
ANSWER : : 1.5 D
4.Which of the following can be used as a meter fall ?
vertical drop fall
flumed glacis fall
unflumed glacis fall
all of the above
ANSWER : : vertical drop fall
5.The meander pattern of a river is developed by
average discharge
dominant discharge
maximum discharge
critical discharge
ANSWER : : dominant discharge
6.Which of the following types of falls use parabolic glacis for energy dissipation ?
vertical drop fall
glacis fall
Montague type fall
inglis fall
ANSWER : : Montague type fall
7.Vertical drop fall is satisfactory for a height upto
0.5 m
1.5 m
3.5 m
5.0 m
ANSWER : : 1.5 m
8.Tortuosity of a meandering river is the ratio of
meander belt to meander length
meander length to meander belt
curved length along the channel to the direct axial length of the river reach
direct axial length of the river reach to curved length along the channel
ANSWER : : curved length along the channel to the direct axial length of the river reach
9.Select the correct statement.
A meander increases the river length but a cut off reduces the river length.
A cutoff increases the river length but a meander reduces the river length.
Both meander and cutoff increase the river length.
Both meander and cutoff decrease the river length.
ANSWER : : A meander increases the river length but a cut off reduces the river length.
10.A straight glacis type fall with a baffle platform and a baffle wall is called
vertical dropfall
glacis fall
Montague type fall
inglis fall
ANSWER : : inglis fall
11.Main purpose of mean water training for rivers is
flood control
to provide sufficient depth of water in navigable channels, during low water periods
to preserve the channel in good shape by efficient disposal of suspended and bed load
all of the above
ANSWER : : to preserve the channel in good shape by efficient disposal of suspended and bed load
12.The main cause of meandering is
presence of an excessive bed slope in the river
degradation
the extra turbulence generated by the excess of river sediment during floods
none of the above
ANSWER : : the extra turbulence generated by the excess of river sediment during floods
13.The ratio of rate of change of the discharge of an outlet to the rate of change of the discharge of distributing channel is called
proportionality
flexibility
setting
sensitivity
ANSWER : s: b
14.Which of the following canal structures is used to remove surplus water from an irrigation channel into a natural drain ?
canal fall
canal outlet
canal escape
canal regulator
ANSWER : : canal escape
15.Which of the following is a flexible outlet ?
submerged pipe outlet
Kennedy’s gauge outlet
Gibb’s outlet
none of the above
ANSWER : : Kennedy’s gauge outlet
16.The drainage water intercepting the canal can be disposed of by passing the canal below the drainage in
aqueduct and syphon aqueduct
aqueduct and super passage
super passage and canal syphon
level crossing
ANSWER : : super passage and canal syphon
17.Wetted perimeter of a regime channel for a discharge of 64 cumecs as per Lacey’s theory will be
19 m
38m
57m
76m
ANSWER : : 38m
18.The aqueduct or superpassage type of works are generally used when
high flood drainage discharge is small
high flood drainage discharge is large and short lived
high flood drainage discharge is large and continues for a long time
none of the above
ANSWER : : high flood drainage discharge is small
19.For a proportional outlet, the flexibility is
zero
between zero and 1
1
greater than 1
ANSWER : : 1
20.River training for depth is achieved by
groynes
construction of dykes or leavees
both (a) and (b)
groynes and bandalling
ANSWER : : groynes and bandalling
21.An aggrading river is a
silting river
scouring river
both silting and scouring river
neither silting nor scouring river
ANSWER : : silting river
22.Tortuosity of a meandering river is always
equal to 1
less than 1
greater than 1
less than or equal to 1
ANSWER : : greater than 1
23.Which of the following canal outlets maintains a constant discharge ?
non-modular outlet
flexible outlet
rigid module
none of the above
ANSWER : : rigid module
24.As per Lacey’s theory, the silt factor is
directly proportional to average par�ticle size
inversely proportional to average par�ticle size
directly proportional to square root of average particle size
not related to average particle size
25.If the R.L’s of canal bed level and high flood level of drainage are 212.0 m and 210.0 m respectively, then cross drainage work will be
aqueduct
superpassage
syphon
syphon aqueduct
ANSWER : : syphon
26.A runoff river plant
is a medium head scheme
generates power during peak hours only
is suitable only on a perennial river
has no pondage at all
ANSWER : : is suitable only on a perennial river
27.A river bend characterized by silting
scouring on concave side
silting on convex side
scouring on convex side and on concave side
scouring on concave side and silting on convex side
ANSWER : : scouring on concave side and silting on convex side
28.The ratio of the average load to the installed capacity of the plant whose reserve capacity is zero will be equal to
load factor
plant factor
utilisation factor
both (a) and (b)
ANSWER : : both (a) and (b)
29.A 6 hours storm had 4 cm of rainfall and the resulting runoff was 2 cm. If
4.5 cm
6.0 cm
7.5 cm
9.0 cm
ANSWER : : 6.0 cm
30.A hydroelectric scheme operating under a head of 80 m will be classified as
low head scheme
medium head scheme
high head scheme
none of the above
ANSWER : : high head scheme
31.A hyetograph is a graphical representation of
rainfall intensity and time
rainfall depth and time
discharge and time
cumulative rainfall and time
ANSWER : : rainfall intensity and time
32.The stream which does not have any base flow contribution is called
perennial stream
intermittent stream
ephemeral stream
none of the above
ANSWER : : ephemeral stream
33.The net speed under which the turbine reaches its peak efficiency is called
design speed
rated speed
gross speed
operating speed
ANSWER : : design speed
34.A land is known as waterlogged
when the permanent wilting point is reached
when gravity drainage has ceased
capillary fringe reaches the root zone of plants
none of the above
ANSWER : : capillary fringe reaches the root zone of plants
35.The stage of river carrying a discharge of Q m7sec at a point is 10 m and slope of water surface is (1/4000). The discharge of a flood at the same point and same stage of 10 m with a water surface slope of(l/1000)willbe
V2 Q m3/sec
0.5 Q mVsec
2 Q m3/sec
4 Q m3/sec
ANSWER : : 2 Q m3/sec
36.The maximum rainfall depth of 300 mm in 24 hours has a return period of 100 years. The probability of 24 hours rainfall equal to or greater than 300 mm occurring at least once in 10 years is given by
(0.99)10
1 – (0.99)10
(0.9)’00
l-(0.9)100
ANSWER : : 1 – (0.99)10
37.A river training work is generally required when the river is
aggrading type
degrading type
meandering type
both (a) and (b)
ANSWER : : meandering type
38.Lining of irrigation channels
increases the waterlogging area
decreases the waterlogging area
does not change the water logging area
none of the above
ANSWER : : decreases the waterlogging area
39.Interception losses are due to i) evaporation ii) transpiration iii) stream flow The correct answer is
only (i)
(i)and(ii)
(ii) and (iii)
(i), (ii) and (iii)
ANSWER : : only (i)
40.The most suitable chemical which can be applied to the water surface for reducing evaporation is
methyl alcohol
ethyl alcohol
cetyl alcohol
butyl alcohol
ANSWER : : cetyl alcohol
41.Select the incorrect statement.
Intensive irrigation should be avoided in areas susceptible to water logging.
Extensive irrigation should be adopted in areas susceptible to water logging.
Lift irrigation increases water logging.
all of the above
ANSWER : : Lift irrigation increases water logging.
42.Which of the following methods is used to estimate flood discharge based on high water marks left over in the past ?
slope-area method
area-velocity method
moving boat method
ultra-sonic method
ANSWER : : slope-area method
43.In India, which of the following is adopted as standard recording raingauge ?
Symon’s raingauge
tipping bucket type
natural syphon type
weighing bucket type
ANSWER : : natural syphon type
44.A repelling groyne is aligned
pointing upstream
pointing downstream
perpendicular to bank
parallel to bank
ANSWER : : pointing upstream
45.The maximum average depth due to one day storm over an area of 100 km2 is 100 mm. Depth-Area-Duration (DAD) curves indicate that for the same area of 100 km2 the maximum average depth for a 3 hour storm will be
100 mm
more than 100 mm
less than 100 mm
none of the above
ANSWER : : more than 100 mm
46.Variability of rainfall is i) largest in regions of high rainfall ii) largest in coastal areas iii) largest in regions of scanty rainfall The correct answer is
only (i)
(i) and (ii)
only (iii)
(ii) and (iii)
ANSWER : : only (iii)
47.The net head under which the turbine reaches its peak efficiency at synchronous speed is called
design head
rated head
gross head
operating head
ANSWER : : design head
48.A runoff river plant is
a low head scheme
a medium head scheme
a high head scheme
none of the above
ANSWER : : a low head scheme
49.To determine the discharge at a section in a stream from its rating curve, the required data are i) slope of water surface at the section ii) stage at the section iii) current meter readings at the section The correct answer is
(i) and (ii)
(ii) and (iii)
only (ii)
only (iii)
ANSWER : : only (ii)
50.To estimate the magnitude of a flood with a return period of T years, Gumbel’s distribution method requires the following data pertaining to annual flood series i) mean value ii) standard deviation iii) length of record iv) coefficient of skew The correct answer is
(i) and (ii)
(i),(iD and (iii)
(i), (ii) and (iv)
(i), (ii), (iii) and (iv)
ANSWER : : (i),(iD and (iii)
51.The peak of a 4 hour flood hydrograph is 240 m3/sec . If the rainfall excess is 80 mm and base flow which is constant is 40 m3/sec, then the peak of 4-hours unit hydrograph will be
20 3/sec
25 m3/sec
30 m3/sec
35 m3/sec
ANSWER : : 25 m3/sec
52.Instantaneous unit hydrograph is a hydrograph of i) unit duration ii) unit rainfall excess iii) infinitely small duration iv) infinitely small rainfall excess The correct answer is
(i) and (ii)
(i)and(iv)
(ii) and (iii)
(iii) and (iv)
ANSWER : : (ii) and (iii)
53.If the risk of a flood occurring in the next 10 years is accepted to 10%, then the return period for design should be
1 + (0.9)010
1 – (0.9)�l0
1/(1-0.9�10)
1/(1+ 0.9010)
ANSWER : : 1/(1-0.9�10)
54.If the demand line drawn from a ridge in a flow mass curve does not intersect the curve again, it indicates that
demand cannot be met by inflow
reservoir was not full at the beginning
both (a) and (b)
none of the above
ANSWER : : demand cannot be met by inflow
55.A unit hydro graph has one unit of
rainfall duration
rainfall excess
time base of direct runoff
discharge
ANSWER : : rainfall excess
56.For an annual flood series arranged in descending order of magnitude, the return for a magnitude listed at position period m in a total data N is
N/(m+l)
m/(N+l)
m/N
(N+l)/m
ANSWER : : (N+l)/m
57.The shape of recession limb of a hydrograph depends upon
basin characteristics only
storm characteristics only
both (a) and (b)
none of the above
ANSWER : : basin characteristics only
58.For a catchment area of 120 km2, the equilibrium discharge in m3/hour of an S-curve obtained by the summation of 6 hour unit hydro graph is
0.2 x 106
0.6 x 106
2.4 xlO6
7.2 xlO6
ANSWER : : 0.2 x 106