160 TOP Irrigation Engineering Multiple choice Questions and Answers pdf free download

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1. Which of the following methods of applying water may be used on rolling land ?
a) boarder flooding
b) check flooding
c) furrow flooding
d) free flooding
Ans: a

2. The value of Sodium Absorption Ratio for high sodium water lies between
a) 0 to 10
b) 10 to 18
c) 18 to 26
d) 26 to 34
Ans: c

3. Optimum depth of kor watering for rice is
a) 135 mm
b) 165 mm
c) 190 mm
d) 215 mm
Ans: c

4. Irrigation water having the concentration of Na++ , Ca++ and Mg++ as 20, 3 and 1 milli-equivalent per litre respectively will be classified as
a) low sodium water
b) medium sodium water
c) high sodium water
d) very high sodium water
Ans: b

5. The duty is largest
a) at the head of water course
b) on the field
c) at the head of a main canal
d) same at all places
Ans: b

6. The "outlet discharge factor" is the duty at the head of
a) main canal
b) branch canal
c) watercourse
d) distributory
 Ans: c

7. The kor depth for rice is 190 mm and kor period is 14 days. The outlet factor for this will be
a) 637 hectares/m3/sec
b) 837 hectares/m3/sec
c) 972 hectares/m3/sec
d) 1172 hectares/m3/sec
Ans: a

8. For supplying water to rabi crop, kharif crop and sugarcane, the channel is designed for a capacity equal to the greater of the water requirement of
a) rabi or kharif
b) rabi and kharif or sugarcane
c) rabi   and  sugarcane  or  kharif and sugarcane
d) rabi or kharif or sugarcane
Ans: c


9. The ratio of the quantity of water stored in the root zone of the crops to the quantity of water actually delivered in the field is known as
a) water conveyance efficiency
b) water application efficiency
c) water use efficiency
d) none of the above
Ans: b

10. The water utilizable by plants is available in soils mainly in the form of
a) gravity water
b) capillary water
c) hydroscopic water
d) chemical water
Ans: b

11. The amount of irrigation water required to meet the evapotranspiration needs of the crop during its full growth is called
a) effective rainfall
b) consumptive use
c) consumptive irrigation requirement
d) net irrigation requirement
Ans: c

12. With the increase in the quantity of water supplied, the yield of most crops
a) increases continuously
b) decreases continuously
c) increases upto a certain limit and then becomes constant
d) increases upto a certain limit and then decreases
Ans: d

13. Hydrograph is the graphical representation of
a) runoff and time
b) surface runoff and time
c) ground waterflow and time
d) rainfall and time
 Ans: a

14. Infiltration rate is always
a) more than the infiltration capacity
b) less than the infiltration capacity
c) equal to or less than the infiltration capacity
d) equal to or more than the infiltration capacity
Ans: c

15. The depth of water required to bring the soil moisture content of a given soil upto its field capacity is called
a) hygroscopic water
b) equivalent moisture
c) soil moisture deficiency
d) pellicular water
Ans: c

19.     Infiltration capacity
a) is a constant factor
b) changes with time
c) changes with location
d) changes with both time and location
 Ans: d

20. Infiltration is the
a) movement of water through the soil
b) absorption of water by soil surface
c) both (a) and (b)
d) none of the above
Ans: a

21. If the intensity of rainfall is more than the infiltration capacity of soil, then the infiltration rate will be
a) equal to rate of rainfall
b) equal to infiltration capacity
c) more than rate of rainfall
d) more than infiltration capacity
Ans: b

22. Cyclonic precipitation is caused by lifting of an air mass due to
a) pressure difference
b) temperature difference
c) natural topographical barriers
d) all of the above
Ans: a

23. Which of the following is a non-recording raingauge ?
a) tipping bucket type raingauge
b) Simon's raingauge
c) Steven's weighing type raingauge
d) floating type raingauge
Ans: b

24. A raingauge should preferably be fixed
a) near the building
b) under the tree
c) in an open space
d) in a closed space
Ans: c

26. Which of the following types of rain gauges is used for measuring rain in remote hilly inaccessible areas ?
a) tipping bucket type
b) weighing type
c) floating type
d) Simon's raingauge
Ans: a

27. Rate of evaporation from a water surface increases if
i)    difference of vapour pressure between water and air is increased
ii)   velocity of wind is decreased
iii) concentration of soluble solids in water is decreased The correct answer is
a) (i) and (ii)
b) (i) and (iii)
c) (ii) and (iii)
d) (i). (ii) and (iii)
Ans: b

28. 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
Ans: b

29. Under the same conditions, which of the following shapes of water surface will give the highest rate of evaporation ?
a) flat water surface
b) convex water surface
c) concave water surface
d) independent of shape of water surface
Ans: b

30. Assertion A : To estimate the rainfall over a catchment, the number of raingauges required per unit area is large for hilly areas.
Reason R : Rainfall gradient is steep. Select your correct answer according to the coding system given below :
a)  Both A and R are true and R is the correct explanation of A
b) Both A and R are true but R is not the correct explanation of A
c) A is true but R is false
d) A is false but R is true
Ans: a

31. When surface of transpiration is submer¬ged under water, then potential evapotranspiration is
a) much more than evapotranspiration
b) much less than evapotranspiration
c) equal to evapotranspiration
d) equal to or less than evapotranspi-ration
Ans: a

33. Unit of runoff in M.K.S. system is
a) cubic metre/sec
b) metre/sec
c) cubic metre
d) square metre
Ans: a

34. The runoff increases with
a) increase in intensity of rain
b) increase in infiltration capacity
c) increase in permeability of soil
d) all of the above
Ans: a

35. The area between the isohyets 45 cm and 55 cm is 100 square km and between 55 cm and 65 cm is 150 square km. The average depth of annua! precipitation over the above basin of 250 square km will be
a) 50 cm
b) 55 cm
c) 56 cm
d) 60 cm
Ans: c

36. A current meter is used to measure the
a) velocity of flow of water
b) depth of flow of water
c) discharge
d) none of the above
Ans: a

37. If it rains between 2 P.M. and 3 P.M. and the entire basin area just starts contributing water at 3 P.M. to the outlet, then time of concentration will be
a) 15 minutes
b) 20 minutes
c) 30 minutes
d) 60 minutes
Ans: d

38. The rainfall on five successive days were measured as 100 mm, 80 mm, 60 mm, 40 mm and 20 mm respectively. If the infiltration index or the storm loss rate for the catchment area is earlier estimated as 50 mm/day, the total surface run off will be
a) 50 mm
b) 60 mm
c) 90 mm
d) 140 mm
Ans: c

39. The normal annual precipitation at stations X, A, B and C are 700 mm, 1000 mm, 900 mm and 800 mm respectively. If the storm precipitation at three station A, B and C were 100 mm, 90 mm and 80 mm respectively, then the storm precipitation for station X will be
a) 70mm
b) 80mm
c) 90 mm
d) 105 mm
Ans: a

40. The best unit duration of storm for a unit hydrograph is
a) 1 hour
b) one-fourth of basin lag
c) one-half of basin lag
d) equal to basin lag
Ans: b

41. The unit hydrograph due to a storm may be obtained by dividing the ordinates of the direct runoff hydrograph by
a) direct runoff volume
b) period of storm
c) total rainfall
d) none of the above
Ans: a

42. The unit hydrograph of a specified duration can be used to evaluate the hydrograph of storms of
a) same duration only
b) same and shorter duration
c) same and longer duration
d) any duration
Ans: d

43. S-hydrograph is used to obtain unit hydrograph of
a)    shorter duration from longer duration
b) longer duration from shorter duration
c) both (a) and (b)
d) none of the above
Ans: c

46. The relation between probability (P) and recurrence interval (T) is given by
a) PT = 1
b) PT2 = 1
c) P/T = 1
d) P/T2 = 1
Ans: a

47. Dimensions of coefficient of transmissibility are
a) M°L°T°
b) rvfL'T"1
c) M° L2 T1
d) M'LV
Ans: c

48. If d is the depth of the aquifer through which water is flowing, then the relationship between permeability k and
transmissibility T is given by
a) T = kd
b) T = k/d
c) T= Vkd
d) k= VTd
Ans: a

49. An artesian aquifer is the one where
a) water surface under the ground is at atmospheric pressure
b) water is under pressure between two impervious strata
c) water table serves as upper surface of zone of saturation
d) none of the above
 Ans: b

50.   A deep well
a) is always deeper than a shallow well
b) has more discharge than a shallow well
c) is weaker structurally than a shallow well
d) both (a) and (b)
Ans: b

51. A multipurpose reservoir is the one which is
a) designed for one purpose but serves more than one purpose
b) planned   and   constructed   to   serve various purposes
c) both (a) and (b)
d) none of the above
Ans: b

52. The useful storage is the volume of water stored in the reservoir between
a) minimum pool level and maximum pool level
b) minimum pool level and normal pool level
c) normal pool level and maximum pool level
d) river bed and minimum pool level
Ans: b

53. The water stored in the reservoir below the minimum pool level is called
a) useful storage
b) dead storage
c) valley storage
d) surcharge storage
Ans: b

54. For a flood control reservoir, the effective storage is equal to
a) useful storage - valley storage
b) useful storage + surcharge storage
c) useful storage + surcharge storage + valley storage
d) useful storage + surcharge storage -valley storage
Ans: d

55. Trap efficiency of a reservoir is a function of
a) capacity/inflow ratio
b) capacity/outflow ratio
c) outflow/inflow ratio
d) none of the above
Ans: a

56. The total capacity of a reservoir is 25 million cubic metres and dead storage is 5 million cubic metres. If the average volume of sediment deposition is 0.10 million cubic metre per year, then the usefulness of the reservoir will start reducing after
a) 50 years
b) 150 years
c) 200 years
d) 250 years
Ans: a

57. The forces, which are considered for the analysis of an elementary profile of a gravity dam under empty reservoir condition, are
i)    Water pressure
ii)   Self weight
iii) Uplift
iv)  Pressure due to earthquake
The correct answer is
a) Only (ii)
b) (i), (ii) and (iii)
c) (i), (ii) and (iv)
d) (i), (ii), (iii) and (iv)
Ans: a

58. When the upstream face of a gravity dam is vertical, then the intensity of water pressure at the water surface and at the base respectively will be
a) 0 and wH212
b) wH2/2and wH2/3
c) wH and 0
d) OandwII
where w is unit weight of water and H is the depth of water.
Ans: d

59. The uplift pressure on a dam can be controlled by
i) constructing cutoff under upstream face
ii) constructing drainage channels bet-ween the dam and its foundation
iii) by pressure grouting in foundation
The corret answer is
a) only (i)
b) both (i) and (ii)
c) both (i) and (iii)
d) (i), (ii) and (iii)
Ans: d

60. The uplift pressure on the face of a drainage gallery in a dam is taken as
a) hydrostatic pressure at toe
b) average of hydrostatic pressure at toe and heel
c) two-third of hydrostatic pressure at toe plus one-third of hydrostatic pressure at heel
d) none of the above
Ans: c

61. Horizontal acceleration due to earthquake results in
a) hydrodynamic pressure
b) inertia force into the body of the dam
c) both (a) and (b)
d) none of the above
Ans: c

62. Hydrodynamic pressure due to earthquake acts at a height of
a) 3H/47I above the base
b) 3H747t below the water surface
c) 4H/371 above the base
d) 4H737t below the water surface where H is the depth of water.
Ans: c

63. The major resisting force in a gravity dam is
a) water pressure
b) wave pressure
c) self-weight of dam
d) uplift pressure
Ans: c

65. When the reservoir is full, the maximum compressive force in a gravity dam is produced
a) at the toe
b) at the heel
c) within the middle third of base
d) at centre of base
Ans: a

66. The maximum permissible eccentricity for no tension at the base of a gravity dam is
a) B/2
b) B/3
c) B/4
d) B/6
Ans: d

67. 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)
 Ans: d

75. For wave action in dams, the maximum height of freeboard is generally taken to be equal to
a) 0.5 hw
b) 0.75 hw
c) 1.25 hw
d) 1.50 hw
where hw is height of wave.
Ans: d

76. As compared to gravity dams, earthen dams
a) are costlier
b) are less susceptible to failure
c) require sound rock foundations
d) require less skilled labour
Ans: d

77. The most suitable material for the central impervious core of a zoned embankment type dam is
a) clay
b) coarse sand
c) silty clay
d) clay mixed with fine sand
Ans: d

78. Seepage through embankments in an earthen dam is controlled by
a) drainage filters
b) relief wells
c) drain trenches
d) provision of downstream berms
Ans: c

79. Seepage through foundation in an earthen dam is controlled by providing
a) rock toe
b) horizontal blanket
c) impervious cut off
d) chimney drain
Ans: c

80. The flow of water after spilling over the weir crest in chute spillway and side channel spillway respectively are
a) at right angle and parallel to weir crest
b) parallel and at right angle to weir crest
c) parallel to weir crest in both
d) at right angle to weir crest in both
Ans: a

81. The discharge passing over an ogee spillway is given by
a) CLH3/2
b) CHL3/2
c) CLH5/2
d) CLH1/2
where, L is effective length of spillway crest and H is the total head over the spillway crest including velocity head.
Ans: a

82. Coefficient of discharge of an ogee spillway
a) depends on depth of approach and upstream slope
b) depends on downstream apron interference and downstream submer¬gence
c) remains constant
d) both (a) and (b)
Ans: d

83. Which of the following spillways is least suitable for an earthen dam ?
a) ogee spillway
b) chute spillway
c) side channel spillway
d) shaft spillway
Ans: a

84. In case of non-availability of space due to topography, the most suitable spillway is
a) straight drop spillway
b) shaft spillway
c) chute spillway
d) ogee spillway
Ans: b

85.     In a chute spillway, the flow is usually
a) uniform
b) subcritical
c) critical
d) super critical
Ans: d

86 For the upstream face of an earthen dam, the most adverse condition for stability of slope is
a) sudden drawdown
b) steady seepage
c) during construction
d) sloughing of slope
Ans: a

87. If there are two canals taking off from each flank of a river, then there will be
a) one divide wall and one undersluice
b) one divide wall and two undersluices
c) two divide walls and one undersluice
d) two divide walls and two undersluices
Ans: d

88. Generally the weir is aligned at right angles to the direction of the main river current because
a) it ensures less length of the weir
b) it gives better discharging capacity
c) it is economical
d) all of the above
Ans: d

89.   The main function of a divide wall is to
a) control the silt entry in the canal
b) prevent river floods from entering the canal
c) separate the undersluices from weir proper
d) provide smooth flow at sufficiently low velocity
Ans: c

90. A divide wall is provided
a) at right angle to the axis of weir
b) parallel to the axis of weir and up-stream of it
c) parallel to the axis of weir and down-stream of it
d) at an inclination to the axis of weir
Ans: a

91. As compared to crest of the normal portion of the weir, the crest of the undersluice portion of weir is kept at
a) lower level
b) higher level
c) same level
d) any of the above depending on the design
Ans: a

92.    Silt ex-cluders are constructed on the
a) river bed upstream of head regulator
b) river bed downstream of head regulator
c) canal bed upstream of head regulator
d) canal bed downstream of head regu-lator
Ans: a

94. According to Khosla's theory, the exit gradient in the absence of a downstream cutoff is
a) 0
b) unity
c) infinity
d) very large
Ans: c

95. The minimum size of stone that will remain at rest in a channel of longitudinal slope S and hydraulic mean depth R is given by
a) 4RS
b) 11 RS
c) 7RS
d) 15 RS
Ans: b

96. The ratio of average values of shear stres¬ses produced on the bed and the banks of a channel due to flowing water is
a) less than 1
b) equal to 1
c) greater than 1
d) equal to zero
Ans: c

97. If the critical shear stress of a channel is xc, then the average value of shear stress required to move the grain on the bank is
a) 0.5 xc
b) 0.75 TC
c) xc
d) 1.33 TC
Ans: b

105. As per Lacey's theory, the silt factor is
a) directly proportional to average par¬ticle size
b) inversely proportional to average par¬ticle size
c) directly proportional to square root of average particle size
d) not related to average particle size
Ans: c

107. Wetted perimeter of a regime channel for a discharge of 64 cumecs as per Lacey's theory will be
a) 19 m
b) 38m
c) 57m
d) 76m
Ans: b

108. Which of the following canal structures is used to remove surplus water from an irrigation channel into a natural drain ?
a) canal fall
b) canal outlet
c) canal escape
d) canal regulator
Ans: c

109. For a proportional outlet, the flexibility is
a) zero
b) between zero and 1
c) 1
d) greater than 1
Ans: c

110. The sensitivity of a rigid module is
a) zero
b) between zero and one
c) 1
d) infinity
Ans: a

111. Which of the following is a flexible outlet ?
a) submerged pipe outlet
b) Kennedy's gauge outlet
c) Gibb's outlet
d) none of the above
Ans: b

112. A straight glacis type fall with a baffle platform and a baffle wall is called
a) vertical dropfall
b) glacis fall
c) Montague type fall
d) inglis fall
Ans: d

113. Which of the following types of falls use parabolic glacis for energy dissipation ?
a) vertical drop fall
b) glacis fall
c) Montague type fall
d) inglis fall
Ans: c

114. In a Sarda type fall, rectangular crest is used for discharge upto
a) 6 cumecs
b) 10 cumecs
c) 14 cumecs
d) 20 cumecs
Ans: c

115. Which of the following can be used as a meter fall ?
a) vertical drop fall
b) flumed glacis fall
c) unflumed glacis fall
d) all of the above
Ans: a

116. Vertical drop fall is satisfactory for a height upto
a) 0.5 m
b) 1.5 m
c) 3.5 m
d) 5.0 m
Ans: b

117. Which of the following canal outlets maintains a constant discharge ?
a) non-modular outlet
b) flexible outlet
c) rigid module
d) none of the above
Ans: c

118. 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
a) proportionality
b) flexibility
c) setting
d) sensitivity
 Ans: b

119. The drainage water intercepting the canal can be disposed of by passing the canal below the drainage in
a) aqueduct and syphon aqueduct
b) aqueduct and super passage
c) super passage and canal syphon
d) level crossing
Ans: c

120. 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
a) aqueduct
b) superpassage
c) syphon
d) syphon aqueduct
Ans: c

121. The aqueduct or superpassage type of works are generally used when
a) high flood drainage discharge is small
b) high flood drainage discharge is large and short lived
c) high flood drainage discharge is large and continues for a long time
d) none of the above
Ans: a

122. An aggrading river is a
a) silting river
b) scouring river
c) both silting and scouring river
d) neither silting nor scouring river
Ans: a

123. 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
Ans: c

124. The meander pattern of a river is deve-loped by
a) average discharge
b) dominant discharge
c) maximum discharge
d) critical discharge
Ans: b

125.   The main cause of meandering is
a) presence of an excessive bed slope in the river
b) degradation
c) the extra turbulence generated by the excess of river sediment during floods
d) none of the above
Ans: c

126. Tortuosity of a meandering river is always
a) equal to 1
b) less than 1
c) greater than 1
d) less than or equal to 1
Ans: c

127. Select the correct statement.
a) A meander increases the river length but a cut off reduces the river length.
b) A cutoff increases the river length but a meander reduces the river length.
c) Both meander and cutoff increase the river length.
d) Both meander and cutoff decrease the river length.
Ans: a

128. River training for depth is achieved by
a) groynes
b) construction of dykes or leavees
c) both (a) and (b)
d) groynes and bandalling
Ans: d

129. Main purpose of mean water training for rivers is
a) flood control
b) to provide sufficient depth of water in navigable channels, during low water periods
c) to preserve the channel in good shape by efficient disposal of suspended and bed load
d) all of the above
Ans: c

130. If D is the depth of scour below original bed, then the width of launching apron is generally taken as
a) 1.2 D
b) 1.5 D
c) 2.0 D
d) 2.5 D
Ans: b

131. Study the following statements.
i)    Levees  are  constructed  parallel  to river flow,
ii)   Spurs are constructed parallel to river flow,
iii)  Levees are constructed transverse to river flow,
iv)  Spurs are constructed transverse to river flow.
The correct answer is
a) (i) and (ii)
b) (i) and (iv)
c) (ii) and (iii)
d) (iii) and (iv)
Ans: b

132. A repelling groyne is aligned
a) pointing upstream
b) pointing downstream
c) perpendicular to bank
d) parallel to bank
Ans: a

133. A river training work is generally required when the river is
a) aggrading type
b) degrading type
c) meandering type
d) both (a) and (b)
Ans: c

135. A river bend characterized by silting
a) scouring on concave side
b) silting on convex side
c) scouring on convex side and on concave side
d) scouring on concave side and silting on convex side
Ans: d

136. Select the incorrect statement.
a) Intensive irrigation should be avoided in areas susceptible to water logging.
b) Extensive irrigation should be adopted in areas susceptible to water logging.
c) Lift irrigation increases water logging.
d) all of the above
Ans: c

137. A land is known as waterlogged
a) when the permanent wilting point is reached
b) when gravity drainage has ceased
c) capillary fringe reaches the root zone of plants
d) none of the above
Ans: c

138. Lining of irrigation channels
a) increases the waterlogging area
b) decreases the waterlogging area
c) does not change the water logging area
d) none of the above
Ans: b

139. A runoff river plant is
a) a low head scheme
b) a medium head scheme
c) a high head scheme
d) none of the above
Ans: a

140. The net speed under which the turbine reaches its peak efficiency is called
a) design speed
b) rated speed
c) gross speed
d) operating speed
Ans: a

141. A runoff river plant
a) is a medium head scheme
b) generates power during peak hours only
c) is suitable only on a perennial river
d) has no pondage at all
Ans: c

142. The net head under which the turbine reaches its peak efficiency at synchronous speed is called
a) design head
b) rated head
c) gross head
d) operating head
Ans: a

143. The ratio of the average load to the installed capacity of the plant whose reserve capacity is zero will be equal to
a) load factor
b) plant factor
c) utilisation factor
d) both (a) and (b)
Ans: d

144. A hydroelectric scheme operating under a head of 80 m will be classified as
a) low head scheme
b) medium head scheme
c) high head scheme
d) none of the above
Ans: c

145. A hyetograph is a graphical representation of
a) rainfall intensity and time
b) rainfall depth and time
c) discharge and time
d) cumulative rainfall and time
Ans: a

146. 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
a) only (i)
b) (i) and (ii)
c) only (iii)
d) (ii) and (iii)
Ans: c

147. In India, which of the following is adopted as standard recording raingauge ?
a) Symon's raingauge
b) tipping bucket type
c) natural syphon type
d) weighing bucket type
Ans: c

148. 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
a) 100 mm
b) more than 100 mm
c) less than 100 mm
d) none of the above
Ans: b

149. 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
a) (0.99)10
b) 1 - (0.99)10
c) (0.9)'00
d) l-(0.9)100
Ans: b

150. The most suitable chemical which can be applied to the water surface for reducing evaporation is
a) methyl alcohol
b) ethyl alcohol
c) cetyl alcohol
d) butyl alcohol
Ans: c

151. Interception losses are due to
i)    evaporation
ii) transpiration
iii) stream flow
The correct answer is
a) only (i)
b) (i)and(ii)
c) (ii) and (iii)
d) (i), (ii) and (iii)
Ans: a

152. A 6 hours storm had 4 cm of rainfall and the resulting runoff was 2 cm. If <j) index remains at the same value, the runoff due to 10 cm of rainfall in 12 hours in the catchment is
a) 4.5 cm
b) 6.0 cm
c) 7.5 cm
d) 9.0 cm
Ans: b

153. Which of the following methods is used to estimate flood discharge based on high water marks left over in the past ?
a) slope-area method
b) area-velocity method
c) moving boat method
d) ultra-sonic method
Ans: a

155 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
a) (i) and (ii)
b) (ii) and (iii)
c) only (ii)
d) only (iii)
Ans: c

156. 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
a) V2 Q m3/sec
b) 0.5 Q mVsec
c) 2 Q m3/sec
d) 4 Q m3/sec
Ans: c

157. The stream which does not have any base flow contribution is called
a) perennial stream
b) intermittent stream
c) ephimeral stream
d) none of the above
Ans: c

158. The flow-mass curve is graphical representation of
a) cumulative discharge and time
b) discharge and percentage probability of flow being equalled or exceeded
c) cumulative  discharge,  volume  and time in chronological order
d) discharge and time in chronological order
 Ans: c

159. If the demand line drawn from a ridge in a flow mass curve does not intersect the curve again, it indicates that
a) demand cannot be met by inflow
b) reservoir was not full at the beginning
c) both (a) and (b)
d) none of the above
Ans: a

160. The shape of recession limb of a hydrograph depends upon
a) basin characteristics only
b) storm characteristics only
c) both (a) and (b)
d) none of the above
Ans: a

161. 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
a) (i) and (ii)
b) (i)and(iv)
c) (ii) and (iii)
d) (iii) and (iv)
Ans: c

162. 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 hydrograph is
a) 0.2 x 106
b) 0.6 x 106
c) 2.4 xlO6
d) 7.2 xlO6
Ans: a

163. A unit hydrograph has one unit of
a) rainfall duration
b) rainfall excess
c) time base of direct runoff
d) discharge
Ans: b

164. 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
a) 20 3/sec
b) 25 m3/sec
c) 30 m3/sec
d) 35 m3/sec
Ans: b

166. 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
a) (i) and (ii)
b) (i),(iD and (iii)
c) (i), (ii) and (iv)
d) (i), (ii), (iii) and (iv)
Ans: b

167. 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
a) N/(m+l)
b) m/(N+l)
c) m/N
d) (N+l)/m
Ans: d

168. If the risk of a flood occurring in the next 10 years is accepted to 10%, then the return period for design should be
a) 1 + (0.9)010
b) 1 - (0.9)°l0
c) 1/(1-0.9°10)
d) 1/(1+ 0.9010)
Ans: c

Latest Irrigation Engineering Objective type Questions for freshers

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1. Why Are Landscapes Irrigated?

Simply stated, irrigation provides the water requirements for sustainability of plants when rainfall is not sufficient.
Ornamentals: Trees and shrubs are irrigated frequently when grown in the nursery and when first planted so that their roots quickly grow out from the root ball and into the soil in the landscape. It is crucial that roots grow as quickly as possible so irrigation can cease. The best way to encourage rapid root growth is frequent light irrigation applied to the root ball after planting. Under ideal conditions (e.g., in non-compacted soils, surrounded by extensive irrigated areas), many Florida-Friendly plants do not require further irrigation except in prolonged drought.
Turf: Although Florida receives substantial rainfall, dry periods are common in the late spring and fall. The dry period in the spring coincides with peak plant water needs due to increasing temperatures, solar radiation, and day length. Due to relatively shallow roots, turfgrasses typically require irrigation at least once a week to maintain quality. On sandy soils, some grasses may need to be irrigated at least two days a week to ensure acceptable quality (Shedd et al., 2008).

2. What Are The Irrigation Requirements For Turfgrass And Landscape Plants?
Note: The term “irrigation requirements” implies well-watered conditions, which means that this is the amount of irrigation water in addition to effective rainfall (that which is stored in the plant root zone and available for use) needed for plant growth and without any water stress.
Ornamentals: All landscape shrubs and trees grown in a nursery and planted in a landscape require water to become established. Under most circumstances, rainfall occurs irregularly, so irrigation is required, at least until plants are established. Trees require about three to four months per inch of caliper (trunk diameter measured 6" from ground) to become established. Shrubs require about 20 to 28 weeks to become established. Irrigation events should be 2 to 3 gallons of water per inch trunk diameter. For example, a 2-inch tree should be watered 4 to 6 gallons at each irrigation event. Water every other day until plants are established.
In addition to initial watering for establishment, irrigation in the year following establishment may be needed to maintain good quality in dry weather. We have little data on irrigation requirements for plants once established, due to the many factors that influence this. These factors include slope, aspect, soil compaction, soil depth, soil volume, width of soil space, depth to water table, wind, season, size of plant at planting, nursery production method, length of time in the container, and root pruning strategies at planting. This research simply has not been done.
Turf: Under well-watered conditions, Stewart and Mills (1967) reported that annual water consumption in South Florida for St. Augustinegrass and bermudagrass averaged 43 inches/yr over five years. For North Florida, Jia et al. (2007) reported 33 inches of total water requirements for bahiagrass. Irrigation requirements for turfgrass in North Florida are on the order of 20–25 inches/yr and 30–35 inches/yr in South Florida, on average (Smajstrla, 1990). These numbers are net irrigation requirements and do not include added irrigation due to the inefficiency inherent in all irrigation systems. See “Efficiencies of Florida Agricultural Irrigation Systems, ” for more information on irrigation efficiency (Smajstrla et al., 1991). In most years, rainfall will contribute substantially to meeting the total water demand of turfgrasses.

3. Do Different Varieties Of Turfgrasses Use Different Amounts Of Water?
Many studies have been conducted on water use of turfgrasses. Most of these studies are conducted under “well-watered” conditions (i.e., no stress due to lack of water) and should not be confused with drought studies where water is withheld and physiological responses of grasses are studied.

All turfgrasses need water to sustain good quality (dense, uniform, green), whether it comes from rainfall or supplemental irrigation. Drought-tolerant grasses will go into dormancy during dry periods, growing more slowly or turning brown until conditions are favorable for growth. When enough soil moisture returns, these grasses can usually recover from drought-induced dormancy rather than dying. For example, bahiagrass is drought-tolerant, but if it is not supplied with adequate water, the drought response of this grass will result in dormancy and a “dead” appearance.

Much of the literature seems to indicate that there may be differences in water use between different warm-season grasses. These disparities likely stem from natural differences in mowing heights (e.g., St. Augustinegrass lawns versus bermudagrass golf turf), fertility, leaf architecture, etc. However, these differences have not been clearly documented in Florida work.

In one study, Zazueta et al. (1999) found that when maintained under UF/IFAS recommendations, bahiagrass had 11 percent higher water use rates than St. Augustinegrass when well-watered, but that the two grasses had similar transpiration rates when under continual stress. A current UF/IFAS study is exploring the water use rates, under well-watered conditions, of several grasses including St. Augustinegrass and bahiagrass.


4. Do Natives Require Less Water? If So, When?
A plant's indigenous status does not affect its fertilizer or irrigation requirements. There is no scientific evidence that native plants require less fertilizer and water than plants not native to Florida. To put it another way, residential and commercial landscapes are often very different from the native conditions where a plant originated, even if they are found in the same state. Additionally, a plant that was previously indigenous to a site may not be adapted to the location any longer, depending on the way the site has been altered. In a recent research study, Florida native shrubs required the same irrigation as non-natives (Scheiber et al., 2007). Fertilizer requirements have not been tested.

5. Will Planting Another Type Of Turfgrass Automatically Result In Water Savings?
The scientific evidence seems to point to human behavior with regard to over-irrigation—not particular plants in the landscape—as the reason for much wasted irrigation water. In addition, there is some evidence that in well-watered (i.e., sustained good quality) conditions, bahiagrass uses slightly more water than St. Augustinegrass. Thus, replacing St. Augustinegrass with bahiagrass will not likely reduce water needs for well-watered conditions. In addition to water, there are many other factors, such as maintenance level, diseases, and pests, that need to be considered related to a turfgrass change.

6. What Is The Proper Way To Irrigate?
Scientifically, irrigation should occur based on plant response to environmental demand. Thus, irrigation frequency and amount will be defined by the environmental demand (i.e., evapotranspiration, ET), soil water-holding capacity and plant root zone depth. Irrigation should be applied such that the soil water reservoir is filled and gravity drainage and runoff do not occur. This approach is detailed in an EDIS publication entitled, “Basic Irrigation Scheduling in Florida,” (Smajstrla et al., 2006), which provides summary information from internationally recognized publications such as “Crop evapotranspiration: Guidelines for computing crop water requirements” (Allen et al., 1998). This scientifically accepted approach aims to result in “well-watered” conditions where no stress is allowed. In addition, an irrigation system must be well-designed and in good repair to apply irrigation efficiently to plants (i.e., without losses due to runoff and deep percolation).

In practice, irrigation is often limited to specific days of the week by water management districts through most of Florida. Thus, landscape plants may undergo varying levels of stress depending on specific site conditions and plant type.

Ornamentals: In the case of newly planted trees and shrubs, water should be applied to the root ball and perhaps the soil just beyond the root ball. In all of the studies over the past twenty-two years on trees in Florida, the area beyond the root ball has not been irrigated. Trees and shrubs establish just fine without broad, landscape-wide (i.e. sprinkler) irrigation. For example, live oak and southern magnolia tree root systems extend to about 14–20 feet in diameter one year after planting in a non-compacted soil without interference from curbs, sidewalks and other soil obstructions.

Turf: Guidelines for turf irrigation include an irrigation system that is well designed and in good repair. Generally, UF/IFAS irrigation guidelines recommend irrigation of ½–¾ inches when 30–50 percent of turfgrass shows signs of wilt during the day. However, if an automatic irrigation system is used under day-of-the-week water restrictions, program run time recommendations are given in “Operation of Residential Irrigation Controllers.” The recommendations in this publication have been further refined into user-friendly guidelines and posted as the FAWN urban irrigation scheduler.

7. Are The Terms “drought-tolerant” And “irrigation Requirement” Related?
Physiologically, tolerance means that the organism tolerates the stress without suffering major damage or is able to continue to function in a stress-induced state. Plants may do this through drought avoidance, physiological adaptations that afford tolerance, or through efficiency mechanisms. Drought avoidance may be escape, such as a plant that reproduces quickly, thereby avoiding drought, or through conservation mechanisms such as stomatal closure, change in leaf canopy or orientation, or cuticular resistance. They may also avoid drought by developing an extensive root system.

Physiological adaptations may include osmotic adjustment, changes in cellular elasticity, and dessication tolerant enzymes, all of which help the plant maintain turgor. Efficiency mechanisms include high water use efficiency (WUE). WUE is often defined as growth per units water provided, photosynthesis per units water, etc. Mechanisms that enhance drought tolerance reduce WUE because growth and carbon assimilation are reduced by leaf firing, rolling, etc.

It is important to note that any plant will require frequent irrigation after planting to ensure survival and establishment. For established plants, the irrigation requirement is defined as the water needed, exclusive of rainfall, for a crop to grow without water stress. It is the difference between ET (evapotranspiration or plant water use) and rainfall. ET may be calculated using one of a number of models, all of which have inherent uncertainty. Using climatological data, one can estimate ET and thus calculate the irrigation requirement on a monthly or annual basis as the difference between ET and effective rainfall. Effective rainfall is rainfall that is estimated to remain in the root zone of the plant. Effective rainfall is the result of total rainfall minus losses to drainage and percolation below the root zone.

Ornamentals: Once drought-tolerant plants, like live oak and burford holly, are established, they can withstand extended dry periods with little or no irrigation.

Turf: All of our grasses in Florida use different mechanisms to go into dormancy during drought stress (leaf firing, rolling, etc.). This metabolic resting state allows them to survive the stress and some of them to resume growth after conditions again become favorable.

8. Can Reclaimed Water Be Used For Irrigation?
Yes, reclaimed water can be and is used for irrigation. In fact, Florida is a leader in the U.S. in the use of reclaimed water for irrigation, with approximately 660 million gallons of reclaimed water being used each day, according to the Florida Department of Environmental Protection 2006 Reuse Inventory.

Reclaimed water does typically contain elevated levels of salts relative to Florida surface and groundwater, except where saltwater intrusion is problematic in coastal areas. The elevated levels of salts in reclaimed water may impact different plant species in varying ways due to differences in salt tolerance. Periodic testing of reclaimed water used in irrigation is recommended.

Also, reclaimed water may contain plant nutrients, which may need to be considered in any fertility program. It is not clear that all the nutrients in reclaimed water are available for plants. Finally, the content of reclaimed irrigation water can vary between different municipalities due to permitting differences and specific differences between wastewater treatment plants.

9. Is There A Correlation Between Plant Water Need And Homeowner Water Use?
Haley et al. (2007) showed that homeowners did use significantly less water in the winter than other seasons. However, overall homeowners over-watered as much as 2–3 times the amount needed by the plants, based on estimates of climate demand. Thus, there is some indication that homeowners reduce irrigation during periods when less is needed; however, it appears that over-irrigation may still occur.

10. Are Day-of-the-week Restrictions Effective At Reducing Water Use?
In a word, yes, but only if they are enforced. Over time, their effectiveness can become reduced. Olmsted (2008) reviewed the literature to determine the effectiveness of day-of-the-week watering restrictions specific to Florida. In Hillsborough and Orange Counties, water use reductions (by utilities) were reported as 17–18 percent; however, no reductions were seen in Seminole County. In South Florida, day-of-the-week restrictions reduced water use up to 21.5 percent during one day/week watering restrictions.

Day-of-the-week restrictions limit flexibility for users who try to plan irrigation based on rainfall trends. In addition, they may encourage over-watering on the allowed day. Just because potable water demands decrease under restrictions, it doesn't mean that irrigation is being applied at the right time and in the right amount—in other words, it's possible that water is still being wasted, even though it may be a smaller amount. However, to a large extent, many landscape plants can survive during most periods of water restriction.

11. Are There Uf/ifas Recommendations For Irrigation, And, If Followed, Do They Provide Water Conservation Benefits?
Ornamentals: Irrigation recommendations for trees can be found at http://hort.ufl.edu/woody/. There is no documentation of how many people follow them. It would be difficult to document the effect of specific practices on ornamental plant material, since these materials only make up part of the planted landscape in most cases. Further, in many irrigation systems, turfgrass and ornamentals and trees are not separated in terms of irrigation zones and thus receive the same amount of irrigation relative to the system programming.

Turf: UF/IFAS recommends watering when 30–50 percent of turfgrass wilts. This should provide water conservation benefits relative to “set it and forget it” time clock programming; however, this has not been documented.

Haley et al. (2007) showed that using the schedule recommended in “Operation of Residential Irrigation Controllers ” reduced watering by 30 percent over a thirty-month study. Thus, if this recommendation were followed, substantial water savings are possible for moderate to high irrigators. The “FAWN urban irrigation scheduler " uses these recommendations in a user-friendly fashion to encourage users to adjust irrigation time clocks to better adjust for climatic demand throughout the year.

12. Which Turfgrasses And Landscape Plants Can Be Grown Without Supplemental Irrigation Or Fertilization?
Some turf species may not need water to survive, but all need water to stay green. Drought tolerance implies that the grasses will “fire” (turn brown) and reduce leaf area to conserve water. Some, such as bahiagrass or centipedegrass, will exhibit better recovery from drought stress. St. Augustinegrass and most of the zoysiagrass varieties will not generally persist well without supplemental irrigation during times of limited rainfall. Fertilization follows a similar trend—bahiagrass and centipedegrass have low fertilization requirements and can persist with relatively low levels of nutrients.

13. What Are The Mechanisms Available To Reduce Over-watering Right Now On Existing Irrigation Systems In Landscapes? How Effective Are These Mechanisms?
Florida statute 373.62 mandates the installation of a working rain sensor device or switch on all automatic irrigation systems installed since 1991. UF/IFAS research has shown that expanding disk rain sensors can be effective at conserving water. Potential savings of 17 to 34 percent were shown at ½-inch and ¼-inch thresholds under normal rainfall frequencies (Cardenas-Lailhacar & Dukes, 2008; Cardenas-Lailhacar et al., 2008).

Ornamentals: In 22 years of irrigation research on trees and shrubs, only drip irrigation and other low-volume irrigation devices have been used. These devices have allowed very little water application while maintaining plant quality, though there are issues with pests such as squirrels chewing through the lines, causing maintenance problems.

Turf: Cardenas-Lailhacar et al. (2008) showed that technology such as soil moisture irrigation controllers can reduce irrigation by 70–90 percent for a range of products and irrigation watering days without negatively impacting turf quality during normal rainfall conditions. Further work with properly installed soil moisture sensor irrigation controllers on homes in Florida shows the potential for 50 percent irrigation savings without a negative impact on landscape quality (Haley & Dukes, 2007). Similar savings appear possible with other “smart irrigation” controllers such as ET controllers.

14. What Is Drip Irrigation?
Drip irrigation is the process of delivering precise amounts of water and nutrients directly to the plant's root zone, drop by drop, offering growers exact irrigation control and efficient use of limited water resources.

15. Why Should I Use Drip Irrigation?
Slow even flow of water to plants and soil: Shrubs and plants will thrive. Application of water and nutrients directly to the plant's roots is the best way to ensure plant health and vitality.

Easy to install - flexible and daptable: Dripperline installs easily in tight, awkwardly shaped areas that are hard to water with conventional spray systems.

Solves spray irrigation: problems No damaging spray on buildings, windows, fencing, or pedestrians in high traffic areas.   Avoids unsightly brown spots on roses and other flowers, since spray never touches the plants. Soil and foliage are kept dry, reducing fungal diseases.

Improved plant growth: Makes plants fuller and healthier. Water and nutrients delivered directly to the root zone promotes healthy plant growth and reduces plant stress. Soil aeration is improved because soil particles are not washed down, decreasing soil compaction and improving root growth.

Saves on maintenance & labor: No moving sprinkler parts to have to repair.  Installs with far less labor than sprinklers.

Unobtrusive & aesthetic: Hidden and lying near the plant, colored  Brown. Doesn't interfere with landscaping or scenery.

Security: No exposed sprinkler heads, pipes or surface dripperlines to trip on or tamper with.  

16. Where Should I Use Drip Irrigation?
You'll be delighted with the fuller blooms and greater beauty of your annuals and perennials when watered. Mature plants and shrubs grow fuller and healthier with dripperline's versus sprinkler watering.

17. Why Micro Irrigation Is Necessary?
To improve the productivity of irrigated land from the present low levels.
To improve use-efficiencies of Water, Energy, Nutrient and Human Effort in Agriculture.
To conserve scarce resources such as Water and Electricity.
To extend the benefits of irrigated agriculture to more people with the available water.
To facilitate better crop management through Fertigation and Chemigation

18. What Are The Advantages Of Micro Irrigation?
Crop Yield Enhancement
Saving in Irrigation Water
Saving in Energy in pumping
Savings in Fertilizer consumption
Quality Improvement of Produce
Improved Pest & Disease Control
Improves Soil Health
Reduced Weed Growth
Reduced Labor Costs
Suitable for Marginal lands
Suitable for inferior quality water

19. What Is Subsurface Drip Irrigation (sdi)?
When a drip tape or tube is buried below the soil surface, it is less vulnerable to damage during cultivation or weeding.  With SDI, water use efficiency is maximized because there is even less evaporation or runoff.

20. What Is Sprinkler Irrigation?
Sprinkler Irrigation is a method of applying irrigation water which is similar to rainfall. Water is distributed through a system of pipes usually by pumping. It is then sprayed into the air and irrigated entire soil surface through spray heads so that it breaks up into small water drops which fall to the ground.

Sprinklers provide efficient coverage for small to large areas and are suitable for use on all types of properties. It is also adaptable to nearly all irrigable soils since sprinklers are available in a wide range of discharge capacity.

21. What Is Microirrigation System?
Microirrigation is frequent application of water directly on or below the soil surface near the root zone of plants. It delivers required and measured quantity of water in relatively small amounts slowly to the individual or groups of plants. Water is applied as continuous drops, tiny streams, or fine spray through emitters placed along a low-pressure delivery system. Such system provides water precisely to plant root zones and maintains ideal moisture conditions for plant growths.

22. Types Of Microirrigation System?
The basic types of microirrigation system are as follows:
Surface System: It is the system in which emitters and laterals are laid on the ground surface along the rows of crops. The emitting devices are located in the root zone area of trees.
Sub-surface System: It is a system in which water is applied slowly below the land surface through emitters. Such systems are generally preferred in semi permanent/permanent installations.
Bubbler system:  In this system the water is applied to the soil surface in a small stream or fountain. Bubbler systems do not require elaborate filtration systems. These are suitable in situations where large amount of water need to be applied in a short period of time and suitable for irrigating trees with wide root zones and high water requirements.
Micro and mini Sprinklers: These are small plastic sprinklers with rotating spinners. The spinners rotate with water pressure and sprinkle the water. These are available in different discharges and diameters of coverage and can operate at low pressure in the range of 1.0 to 2kg/cm2. Water is given only to the root zone area as in the case of drip irrigation but not to the entire ground surface as done in the case of sprinkler irrigation method.

Pulse:  Pulse system uses high discharge rate emitters and consequently has short water application time.  The primary advantage of this system is a possible reduction in the clogging problem.

Biwall: It is extruded dual chamber micro-irrigation tubing manufactured from Linear Low Density Polyethylene (LLDPE). This system is suitable for all closely spaced row crops like sugarcane, cotton, vegetables, onion, tea etc.

23. How About Those Tight Or Awkwardly Shaped Areas That Are Difficult To Water With Conventional Spray Systems?
Dripper lines solve the problem and avoid spraying your walls, window and fences. Consistent watering with dripper lines helps establish and protect new shrub beds and planting areas.

24. Can I Save Money Using Drip Irrigation Vs. Traditional Spray Sprinklers?
It is frequently more profitable to install a systems when you are dealing with long, narrow strips, awkwardly shaped areas, or tree, shrub and bedding plant areas - both from a materials cost and labor standpoint. To help the minimize liability and vandalism and saves your customers' costs associated with continued maintenance and water usage.  A simple shrub bed installation is quick and easy, either buried 4" below the surface or beneath mulch.

25. What About Different Soil Types? Even Clay?
Subsurface irrigation works better in heavy clay or sand conditions than traditional sprinkler systems. Even "heavy clay" and "sandy" soils are a mixture sand, silt and clay. Loam, which contains equal proportions of sand, silt and clay, is ideal. However, plants can thrive in a very broad spectrum of soil textures when subsurface watering is applied at the proper rate, with appropriate spacing. Different soils create typical wetting pattern shades as seen at right. Note the dramatic overlap ensuring total coverage throughout varying root zone depths.

Drip irrigation works great in clay soils. What most people regard as "heavy clay" and "sandy" soils are actually mixtures of sand, silt and clay which will allow for adequate water movement and retention between soil particles.

26. Does Water Only Move Downward, Pulled By Gravity?
When applied slowly (as in drip irrigation) water radiates outward from its source point, creating an overlapping wetting pattern beneath the ground. See the "wetted pattern" illustration" at right. When applied slowly to the soil at a single point, water moves through the soil in two ways:

Downward pulled by gravity.
Outward and upward, pulled by a capillary action.

27. How Can I Tell The System Is Working?
There are several ways to verify that your system is working, including:
Feel for moisture just below the surface of the soil directly above a dripper.
Run micro tubing to the surface at the end of a zone and use it as a point source dripper.
Install a flag indicator at the end of zone.
Monitor flow at the water meter.
Because water travels both upward and outward from the dripper, the soil will usually be damp at, or close to, the surface.

28. Will An Automatic Sprinkler System Use More Water Than I'm Currently Using?
No. In fact, it will conserve water. The system's controller and rain sensor will be set so you receive only the amount of water you need. You will not over-water or under-water your lawn with an automatic sprinkler system.

29. Does Having A Sprinkler System Really Save Time?
Yes. You won't have to spend another minute of your valuable leisure time watering the lawn. Whether you are home or away your system will do the watering for you!

30. Will Automatic Sprinkler System Water As Well As I Can Water By Hand?
It will do a much better job because a professionally designed system will deliver exactly the right amount of water to individual lawn and garden areas.

31. We Generally Get 40 Or More Inches Of Rainfall A Year. Do We Really Need A Sprinkler System?
If it rained at your house every three days the same exact amount each time you probably would not need a sprinkler system. But nature does not work that way, and the only way to ensure healthy, lush growth is to make certain your lawn and plants receive a regularly timed, evenly measured amount of water. In the dry season when there is little or no rain, your yard can suffer damage after just a few days without water.

32. How To Protect The Drip System From Rat?
By providing raised beds over the laterals.

33. Emitter Is Not Functioning Well, Why?
It’s due to some fine particles clogging the emitter because of bad quality of water. In that case we should provide filtration unit for removing fine particulars present in the water.

34. How Much Subsidy Government Gives For Installation Of Drip System?
50 % of installation drip irrigation cost as given as subsidy by the government.

35. Which Type Of Mulching Material Is Useful For Controlling Weeds?
Normally Black polythene film is recommended for controlling weeds.

36. How To Clean The Drip System?
Open all end caps in lateral; main and submain pipes and operate the motor at least ten minutes to remove all fine particles presents in drip irrigation system.

37. How To Reduce The Drip System Cost?
In Paired row system, the total number of lateral is less comparing to single row system.  Total cost of unit will reduce by adopting this method.

38. How Much Depth Is Needed For Laying Sub Main In The Field?
Normally we recommended 60-70 cm from the top of the soil.

39. Venturi Is Not Working Well, Why?
There is less pressure in pressure gauge or leaking problem in venturi system or pump is not functioning well.

40. Why Water Is Not Flowing Upto Lateral End?
Because of holes, bents and cuts in laterals. To avoid this close the holes and cut and remove the bends present in the laterals.

41. While Removing The End Plug White Mixture Is Coming. Why?
This is due to uncleaned lateral and more salinity in water. This can be avoided by cleaning the laterals fortnightly.

42. Some Times Oily Gum Material Comes Out On Opening The Lateral End. Why?
Presence of more algae or ferrous material in water. Clean the laterals with water or give chemical treatment.

43. Why Pressure Gauge Is Not Working Some Times?
Rain water entry inside. Corrosion in gauge pointer damage. Provide plastic cover and fix pointer properly.

44. How Drop In Pressure Occurs?
Leakage in main opened outlet and low water level in well. Arrest the leakage and close outlet and lower the pump with reference to well water level.

45. What Is The Reason For More Pressure At The Entry Of Sand Filter?
Provide bypass before filter and regulate pressure. Place filter element properly. Fill required quantity of sand.

46. Leakage Of Water From Air Release Valve. Why?
Due to damaged air release valve ring. Replace the damaged ring.

47. Suitable Crops For Drip Irrigation?
All vegetable crops, Flower and fruit crops and Tree crops.

48. Suitable Crops For Sprinkler Irrigation?
Lemongrass, Groundnut, Pulses, Sugarcane and Tubercrops.

Latest Irrigation Engineering Interview Questions for freshers and Experienced pdf