101. 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
102. 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
103. 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
104. 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
105. 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
106. 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
107. 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
108. A repelling groyne is aligned
a) pointing upstream
b) pointing downstream
c) perpendicular to bank
d) parallel to bank
Ans: a
109. 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
110. 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
111. 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
112. 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
113. 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
114. 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
115. 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
116. 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
117. 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
118. 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
119. 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
120. 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
121. 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
122. 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
123. 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
124. 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
125. 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
126. 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
127. 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
128. 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
129. 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
130. 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
131. The stream which does not have any base flow contribution is called
a) perennial stream
b) intermittent stream
c) ephemeral stream
d) none of the above
Ans: c
132. The flow-mass curve is graphical representation of
a) cumulative discharge and time
b) discharge and percentage probability of flow being equaled or exceeded
c) cumulative discharge, volume and time in chronological order
d) discharge and time in chronological order
Ans: c
133. 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
134. 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
135. 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
136. For a catchment area of 120 km2, the equilibrium discharge in m3/hour of an S-curve obtained by the summation of 6Â hour unit hydro graph is
a) 0.2 x 106
b) 0.6 x 106
c) 2.4 x106
d) 7.2 x106
Ans: a
137. A unit hydro graph has one unit of
a) rainfall duration
b) rainfall excess
c) time base of direct runoff
d) discharge
Ans: b
138. 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 m3/sec
b) 25 m3/sec
c) 30 m3/sec
d) 35 m3/sec
Ans: b
139. 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
140. 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
141. 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