Category: Irrigation Engineering Objective Questions

250+ TOP MCQs on Hydropower and Answers

Irrigation Engineering Multiple Choice Questions on “Hydropower”.

1. The minimum power which a hydropower plant can generate throughout the year is called as ________________
a) power plant capacity
b) power plant load
c) firm power
d) water power
Answer: c
Clarification: The firm power is the net amount of power which is continuously available from a plant without any break on a guaranteed basis. The consumers can always be sure of getting this power and this power is available under the most adverse hydraulic conditions.

2. If the peak load for a power plant equals the plant capacity then the ratio of the capacity factor to load factor will be _________________
a) 1
b) 0
c) < 1
d) > 1
Answer: a
Clarification: Load factor = Average load over a certain period / Peak load during that period
Capacity factor = Average load over a given time period / Plant capacity
Since, Plant capacity = Peak load
Ratio of CF / LF = 1.

3. If the peak load on a power plant having a capacity of 100 MW is 70 MW during a given week and the energy produced is 58, 80,000 kWh, the capacity factor for the plant for the week will be ___________________
a) 35%
b) 50%
c) 70%
d) 65%
Answer: a
Clarification: Capacity factor = Average load/ Plant capacity
Average load = Energy produced / Time (in hours) = 58,80,000 / 7 x 24 = 35000 kW
C.F = 35 MW / 100 MW = 0.35 (or 35%).

4. During a certain week a power plant turns out 84,00,000 kWh and the peak load during the week is 100,000 kW. What is the load factor during the week?
a) 40%
b) 45%
c) 50%
d) 60%
Answer: c
Clarification: Load factor can be defined as the ratio of average load to the peak load over a given period.
Average load = 84,000,000 / (24 x 7) = 50,000 kW
L.F = Average load / Peak load = 50,000 / 100,000 = 0.5 or 50%.

5. A canal drop is 6 meters and discharges available through the turbine is 50 cumec. Find the electrical energy available.
a) 2352 KW
b) 2352 MW
c) 2.352 kW
d) 235.2 kW
Answer: a
Clarification: The electrical energy (in kW) = 7.84 Q H (using 80% efficiency) where H is the design head in meters and Q is the design discharge in cumecs.
Electrical energy = 7.84 x 50 x 6 = 2352 kW.

6. The ratio of maximum power utilised to the maximum power available is _____________
a) power factor
b) plant use factor
c) reserve capacity
d) capacity factor
Answer: b
Clarification: Plant use factor is nothing but utilization factor which can be defined as the ratio of maximum power utilized to the maximum power available if the water head is assumed to be constant. The value usually varies from 0.4 to 0.9 for a hydel plant.

7. The net amount of power which is continuously available from a plant without any break is known as _____________
a) firm power
b) secondary power
c) power factor
d) utilization factor
Answer: a
Clarification: Secondary power is the excess power available over firm power during peak-off hours. It is supplied to consumers as and when available basis. Power factor is the ratio of actual power (in kW) to the apparent power (in kilo volt-ampere).

8. The value of power factor is generally _____________________
a) equal to unity
b) less than unity
c) greater than unity
d) equal to zero
Answer: b
Clarification: The value of power factor depends upon the relationship between the inductance and resistance in the load and it can never be greater than unity. The usual system load has a power factor varying from 0.8 to 0.9. But if various induction motors are installed in the load, the value will be 0.5.

9. To ensure maximum overall plant efficiency, the rated head should be equal to ______________
a) the design head
b) the gross head
c) the operating head
d) effective head
Answer: a
Clarification: The Rated head is the head at which the turbine functioning at full gate opening will produce a power output. It is nothing but the specified head that is in the nameplate of the turbine. This is equal to the design head of the turbine so as to ensure maximum overall plant efficiency.

10. The difference of head at the point of entry and exit of turbine is _______________
a) design head
b) gross head
c) effective head
d) rated head
Answer: c
Clarification: Design head is the net head under which the turbine reaches peak efficiency. The difference in the water level elevations at the point of diversion of water for the hydel scheme and the point of return of water back to the river is called a gross head. The rated head is the head that is specified in the name-plate of the turbine.

11. The load on a hydel plant varies from a minimum of 10,000 kW to a maximum of 35,000 kW. Two turbo-generators of capacities 20,000 kW each have been installed. Calculate Plant factor.
a) 50%
b) 51%
c) 56.2%
d) 59.7%
Answer: c
Clarification: Plant factor can be defined as the ratio of the energy actually produced (Average load) to the maximum energy that can be produced at a particular time.
Since two turbo generators are installed, the total installed capacity = 40000 kW
P.F = [(10000 + 35000) / 2] / 40000 = 56%.

12. Calculate utilisation factor if the maximum power utilised is 40,000 kW and two turbo generators installed each of capacity 23,000 kW.
a) 73%
b) 87%
c) 57.5%
d) 63%
Answer: b
Clarification: Utilisation factor = Maximum power utilised / Maximum power available
U.F = 40,000 / (2 x 23000) = 86.9% (since two generators are installed).

13. If the peak load on a power plant having a capacity of 100 MW is 70 MW during a given week. Calculate the utilization factor.
a) 0.35
b) 0.50
c) 0.70
d) 0.60
Answer: c
Clarification: The utilization factor is the ratio of the maximum power utilized to the maximum power available.
U.F = Max power utilised/ Max power available = 70 / 100 = 0.7.

14. 400 cumecs of water are being released from dam storage to meet the downstream demand through the turbines of the connected hydro plant. The effective head of water acting on the turbines is 50 m. The efficiency of the hydro plant is 0.8. The electrical power generated from this plant is __________________
a) 1,56,800 MW
b) 156.8 M kW
c) 156.8 MW
d) 156.8 kW
Answer: c
Clarification: Using 80% efficiency, Electrical energy = 7.84 QH where H is the design head in meters and Q is the design discharge in cumecs.
Electrical energy = 7.84 x 400 x 50 = 1, 56,800 kW = 156.80 MW.

15. What is the highest elevation of water level that can be maintained in the reservoir without any spillway discharge either with gated or non-gated spillway?
a) Normal Water level
b) Minimum Water level
c) Weighted average level
d) Operating head
Answer: a
Clarification: Minimum water level is that elevation of water level which produces minimum net head on the power units i.e. 65% of the design head. The weighted average level is the level above and below which equal amounts of power are developed during an average year. Operating head is the difference of elevation of entrance and the tail-race exit.

250+ TOP MCQs on Stability of Earthen Slopes and Answers

Irrigation Engineering Multiple Choice Questions on “Stability of Earthen Slopes”.

1. Which of the following method is also called as the Slices method?
a) Fellenius method
b) Swedish slip circle method
c) Bishop’s simplified method
d) Spencer’s method
Answer: b
Clarification: Swedish circle method is also called as the method of slices and Fellenius method is a modified version of it. Swedish circle method assumes the condition of plain strain with failure along a cylindrical arc. The location of the center of possible failure arc is assumed and the earth mass is divided into slices.

2. In Fellenius method for small values of angle of internal friction of soil, the critical arc passes ________________
a) through the toe of the slope
b) above the toe of the slope
c) below the toe of the slope
d) anywhere near the toe of the slope
Answer: c
Clarification: The critical arc passes below the toe of the slope for small values of angle of internal friction of the soil (0° to 15°) if the angle of inclination is less than 53°. For large values of internal friction angle, the critical arc passes through the slope.

3. What is the correct expression of equivalent liquid unit weight?
a) ϒeq.tan2 [45 – Φ/2]
b) ϒeq.tan2 [45 + Φ/2]
c) ϒeq.tan [45 – Φ/2]
d) ϒeq.tan [45 + Φ/2]
Answer: a
Clarification: This term is used in the analysis of the stability of the foundation against shear. It is based on the assumption that soil has an equivalent liquid unit weight which would produce the same shear stress as the soil itself.
ϒeq.tan2 [45 – Φ/2]
where ϒeq = the equivalent unit weight of dry soil in foundation and dam and Φ = the equivalent angle of internal friction.

4. Calculate the maximum shear-stress induced if the horizontal average shear stress induced in u/s portion of the dam at the base is 36.45 kN/m2.
a) 43.74 kN/m2
b) 47.38 kN/m2
c) 51.03 kN/m2
d) 54.67 kN/m2
Answer: c
Clarification: By Photoelastic studies, the maximum intensity of shear stress is equal to 1.4 times the average shear intensity at a distance 0.6 B from the heel.
Ꞇmax = 1.4 Ꞇavg = 1.4 x 36.45 = 51.03 kN/m2.

5. Calculate the factor of safety at the point of maximum shear if unit shearing resistance is 97.9 kN/m2 and the maximum shear-stress induced is 55.72 kN/m2. Check whether the dam is safe or unsafe.
a) F.O.S = 1.93 and safe
b) F.O.S = 1.75 and unsafe
c) F.O.S = 0.569 and safe
d) F.O.S = 1.75 and safe
Answer: d
Clarification: F.O.S will be the ratio of the unit shearing resistance to the maximum shear stress developed.
F.O.S = 97.9 / 55.72 = 1.75
this value should be more than unity, hence safe.

250+ TOP MCQs on Various Types of Dams and Answers

Irrigation Engineering Multiple Choice Questions on “Various Types of Dams”.

1. Gravity dam is most suitable when the foundation is _______________
a) weak
b) strong
c) with heavy overburden
d) rocky but cracked
Answer: b
Clarification: A gravity dam is the one in which the stability against external load is achieved by the weight of the dam itself. This type of dam requires minimum maintenance. It can be constructed on any site where the natural foundation is strong enough to bear the weight of the dam.

2. Which of the following type of dam is built in areas where the foundation is not strong enough to bear the weight of concrete?
a) Rock-fill dam
b) Earth dam
c) Gravity dam
d) Arch dam
Answer: b
Clarification: An earth dam is built up by compacting successive layers of the earth with vibrating or heavy machinery. It is built in areas where the earth is more easily available as compared to concrete or stone or rock.

3. Which of the following dam is partly earthen and partly rockfill?
a) Tehri dam
b) Koyna dam
c) Sardar Sarovar dam
d) Bhakra dam
Answer: a
Clarification: The Koyna dam is a rubble-concrete dam which is built on Koyna River near Satara district in Maharashtra. The Sardar Sarovar Dam is a gravity dam on the Narmada River, Gujrat and Bhakra dam is also a concrete gravity dam.

4. Idukki dam is a type of ________________
a) rockfill dam
b) a hollow masonry gravity dam
c) arch dam
d) steel dam
Answer: c
Clarification: The Idukki dam is a double curvature arch dam constructed across the Periyar River and has a height of about 170 m. It is one of the highest arch dams in Asia and it was constructed and owned by Kerala State Electricity Board.

5. In which of the following dam the weight of water is carried by a deck of RCC or by arches that share the weight burden?
a) Earth dams
b) Rockfill dams
c) A hollow masonry gravity dam
d) Timber dam
Answer: c
Clarification: The Hollow Masonry Gravity dam contains less concrete or masonry (about 35 to 40%) than solid masonry gravity dam. They are difficult to build and the labor cost is too high to build its complex structure.

6. It is possible to construct steel dam only up to a height of ____________
a) 5 m
b) 10 m
c) 20 m
d) 50 m
Answer: c
Clarification: Steel dams are not in common use and it is possible to build the dam up to a height of 18 to 20 m. They are used as coffer dams for the construction of permanent dams.

7. The temporary structures that are built to enclose certain worksite is ______________
a) storage dam
b) coffer dam
c) timber dam
d) steel dam
Answer: b
Clarification: Coffer dams are temporary structures that are used to divert the flow to enable construction activity in the main river channel. It is also used to enclose certain work site. Steel and timber dams are also used as coffer dams.

8. Which of the following dam is suitable for narrow valleys?
a) Arch dam
b) Steel dam
c) Coffer dam
d) Timber dam
Answer: a
Clarification: An arch dam is that dam in which stability of the dam against external forces is obtained partly due to the weight of the dam and partly due to transferring horizontal pressure to the abutments. The presence of sound abutments is an important requirement and is suitable for narrow valleys.

9. When sand and gravel foundation strata are available at a proposed dam site of moderate height, the dam may be of the type ________________
a) earthen or rockfill dam
b) masonry gravity dam
c) concrete gravity dam
d) double arch dam
Answer: a
Clarification: The piles of loose rocks and boulders in the river bed are nothing but rockfill. On the upstream face of the dam, a slab of reinforced concrete is often laid to make it watertight.

10. According to the Hydraulic design, the dams are classified as _________
a) diversion and detention Dams
b) storage and diversion dams
c) overflow and non-overflow dam
d) arch and buttress dam
Answer: c
Clarification: The dams are classified as Over-flow dam and Non-over flow dam according to the hydraulic design. When water flows over the crest of the dam it is known as the overflow dam. The dams which do not allow water to flow over the crest of the dam is called non-overflow dam.

250+ TOP MCQs on Types of Rigid Modules and Cattle Crossings and Answers

Irrigation Engineering Multiple Choice Questions on “Types of Rigid Modules and Cattle Crossings”.

1. Which of the following is not a type of rigid module?
a) Gibb’s module
b) Khanna’s rigid module
c) Foote module
d) Crump’s proportional module
Answer: d
Clarification: Crump’s Adjustable Proportional Module is also called Adjustable Orifice Semi-Module. In this type, a cast-iron roof block is provided at the entrance end which is screwed to the masonry entrance by the bolts fixed in the masonry. This block is given the lemniscate curve at the lower end on the entrance side.

2. The discharge range of Gibb’s module varies from ____________
a) 0.03 to 0.45 cumec
b) 0.01 to 0.03 cumec
c) 0.45 to 0.55 cumec
d) 0.55 to 0.75 cumec
Answer: a
Clarification: The discharge range of Gibb’s rigid module varies from 1 to 16 cusecs or 0.03 to 0.45 cumecs. It is often economical to construct it in R.C.C for lower values of discharge i.e. 1 to 3 cusecs. For discharge value greater than 3 cusecs it can be constructed in brick masonry.

3. Choose the incorrect statement.
i. Bed bars are constructed in canals at the toe of the canal lining to prevent slippage of the lining.
ii. Cattle crossings also provide safety to cattle that are swept away by currents besides their usual function of helping the cattle to cross the canal.
iii. A canal escape helps in supplying irrigation water to the downstream watercourses.
a) i and ii
b) i only
c) ii only
d) i, ii and iii
Answer: d
Clarification: Canal escape helps in removing surplus water from an irrigation canal into a natural drain. The cattle crossing are not of much use on canals carrying considerable water depths and for the ones who don’t know swimming. Bed bars help in desilting the canal section during its maintenance and indicate the correct alignment and bed levels of the canal.

4. The outlet discharge is maintained constant and it is not at all dependent on the water levels in the parent and the field channels in _________________
a) non-modular outlet
b) modular outlet
c) semi-modular outlet
d) proportional outlet
Answer: b
Clarification: A non-modular outlet is the one in which discharge is directly dependent on the working head. In the semi-modular outlet, the discharge is directly dependent on the water level in the parent channel. A proportional module is a type of semi-module.

5. Gibb’s module is a type of outlet which ensures constant discharge even if the water levels in the supply channel and watercourse fluctuate.
a) True
b) False
Answer: a
Clarification: An upward rotational flow is imparted if the head causing flow increases at the outer wall restricting against the baffles. The water spins round in the compartment between two successive baffles and finally drops on the incoming water stream of water. This dissipates excess energy and helps in maintaining constant discharge for a wide variation in the head.

6. A baffle wall is a sort of weir constructed at the end of the cistern to:
i. To prevent any excess amount of discharge likely to pass through the module
ii. The baffle plates are inserted in the eddy chamber sloping from the outer wall towards the inner wall
iii. Head up the water to its upstream to such a height that hydraulic jump is formed
Which of the following statement is correct?
a) i only
b) i and iii
c) i and ii
d) i, ii and iii
Answer: d
Clarification: The baffle plates are inserted in the eddy chamber at required height sloping towards the outer wall which helps in preventing any excess discharge to pass through the module. It dissipates the energy by creating an upward rotational flow spinning in between two successive baffles. The number of baffles coming into action depends on the variation in the head.

7. In cattle crossings, the exact distance to be kept between the two ramps on the same side should theoretically be ________
a) 2 BV/U
b) 2 BVU
c) 2 BU
d) 2 BU/ V
Answer: a
Clarification: Theoretically, the exact distance to be kept between the two ramps on the same side should be 2 BV / U where, B = width of the channel, V = average flow velocity of water in the channel and U = the speed with which cattle swim. The distance is kept a little longer than shorter even if the cattle reach the opposite side too nearer they will get at the ramp.

8. For canals carrying smaller water depths, a ramp is provided for the entry and exit as cattle crossings.
a) True
b) False
Answer: a
Clarification: A ramp is provided for the entry and another ramp opposite to it is provided for the exit for smaller water depths or the order 0.75 m or so. The cattle move from one bank on the ramp comes to the bottom of the canal within the water further goes across by walking over the exit ramp.

9. Bed bars are used _______________
i. To serve as permanent reference marks
ii. To correct alignment and theoretical bed levels of the canal
iii. Helps in desilting the canal section during its maintenance
Which of the following function of bed bars is/ are correct?
a) i and ii
b) i and iii
c) ii and iii
d) i, ii and iii
Answer: d
Clarification: These are masonry or concrete toe wall-like structure constructed at suitable intervals, the R.L of which is taken by double levelling accurately. The depth of the block and its cross-section is kept substantial enough so that it is not disturbed by the flowing water and is safe against scoring. The bed bars helps in keeping a check on the behaviour of the canal w.r.t silting and scouring tendencies.

10. Gibb’s module holds good for the standard design in which _________
a) Outlet index m = 2 and H/D = 1/7
b) Outlet index m = 1/3 and H/D = 1/7
c) Outlet index m = 5/3 and H/D = 1/7
d) Outlet index m = 2/3 and H/D = 1/7
Answer: a
Clarification: It is a modular outlet with costly and complicated arrangements. It is based on the free vortex flow and holds good for the standard design in which outlet index = 2 and H/D = 1/7 where H is the head at the outer circumference and D is the difference of the level measured from the minimum water level in the parent channel to the floor of eddy chamber.

250+ TOP MCQs on Seepage Theories – Failure of Hydraulic Structure and Answers

Irrigation Engineering Multiple Choice Questions on “Seepage Theories – Failure of Hydraulic Structure”.

1. What are the two main causes of failure of hydraulic structure on the pervious foundation?
a) Seepage and Over-turning
b) Undermining and Uplift
c) Over-turning and Piping
d) Overturning and Uplift
Answer: b
Clarification: Whenever a hydraulic structure is founded on a pervious foundation, it is subjected to seepage of water beneath the structure in addition to all other forces. The water seeping below endangers the stability of the structure and may cause its failure either by Piping or Undermining and Direct uplift.

2. The uplift pressure is not important for the upstream apron during considerations of failure due to uplift.
a) True
b) False
Answer: a
Clarification: When the apron is not sufficiently strong to counteract the excessive upward pressure, it may fail by rupture. The uplift pressure is not important for an upstream apron because the downward weight of stored water on the upstream apron is sufficient to neutralize the effect.

3. The structure finally subsides in the hollow formed in the foundation in which failure?
a) Collapse
b) Overturning
c) Undermining
d) Uplift
Answer: c
Clarification: Undermining takes place due to excessive percolation of water under pressure below the foundation. The seepage water when retains a sufficient residual force at the emerging downstream end, it may dislodge and lift up the soil particles leading to the increased porosity by progressive removal of the soil. This leads to the failure of the structure as it ultimately subsides in the hollow so formed.

4. Heave piping may occur on the _______________
a) downstream of sheet pile or cut off wall
b) upstream of sheet pile or cut off wall
c) body of earth structure
d) below the foundation
Answer: a
Clarification: As per Terzaghi, heave piping may occur within a distance of D/2 on the downstream of sheet pile where D is the embedment depth of sheet pile. The entire soil mass in the zone gets heaves up and is blown out by the percolating water when the seepage pressure at any level is greater than the submerged weight of soil above that level.

5. Backward erosion piping takes place when the phreatic line cuts the downstream face of the dam and seepage pressure is high.
a) True
b) False
Answer: a
Clarification: Backward erosion piping is an important failure mechanism for water-retaining structure and local disruption of the downstream top layer leads to concentrated seepage flow. This results in erosion that continues in the upward direction. It is ensured that the phreatic lines never touch the downstream side of the earth dam to avoid failure.

6. The safety of a hydraulic structure founded on a pervious foundation can be ensured by:
i. Provision sufficient length of its concrete floor.
ii. Providing sufficient depth of its concrete floor.
iii. Provision a downstream cutoff of some reasonable depth.
a) i and ii
b) i and iii
c) i, ii and iii
d) ii and iii
Answer: c
Clarification: The safety against piping can be ensured by providing sufficient creep length as per Bligh’s theory. The thickness of the concrete floor is generally increased by 33% to allow a suitable factor of safety for the worst conditions. A reasonably deep vertical cutoff is also provided at the downstream end of the floor to prevent undermining.

250+ TOP MCQs on Canal Lining – Requirements and Answers

Irrigation Engineering Multiple Choice Questions on “Canal Lining – Requirements”.

1. What is the safe limiting velocity for cement concrete lining?
a) 1.5 m/s
b) 2.2 m/s
c) 2.7 m/s
d) 1.8 m/s
Answer: c
Clarification: For cement concrete lining, the safe limiting velocity is 2.7 m/s. For boulder lining, it is 1.5 m/s and for burnt clay tile lining it is approximately 1.8 m/s. This serves as a guide for selecting canal slopes and alignments.

2. The most economical type of lining is the one which shows ____________
a) minimum benefit-cost ratio
b) maximum benefit-cost ratio
c) zero benefit-cost ratio
d) benefit-cost ratio = 1
Answer: b
Clarification: The one which shows the maximum annual benefit-cost ratio is the most economical lining. It may have a higher cost initially but longer life than another type of lining having a lesser value of the annual benefit-cost ratio.

3. Which of the following guideline is not recommended for the choice of lining when the bed width of the canal is up to 3 m?
a) Single burnt clay tile lining or brick lining
b) PCC slab lining
c) Flexible membrane lining with adequate earth/tile cover
d) In-situ cement concrete lining in bed as well as on sides
Answer: d
Clarification: The choice of suitable lining for different size of a canal depends on canal slopes and alignments, size and importance of canal, the climate of the area, initial expenditure, etc. In-situ cement concrete lining in bed and on sides is generally preferred for canals when bed width is greater than 8 m.

4. Which of the following is not a cause for the hydrostatic pressure on the lining?
a) Seeping of the rainwater in the backfill
b) When the water table remains below the canal bed
c) The backfill is of low drainage
d) The backfill is of high permeability (i.e. > 3 cm/sec)
Answer: d
Clarification: If the subgrade is made of clear gravel or sand of good permeability (> 3 cm/sec) and the water table is not likely to go above the canal bed no drainage arrangements may be necessary. There will be no appreciable time lag in the dissipation of drawdown pore pressures in the subgrade for such case.

5. Drainage relief pockets are provided ___________
a) at isolated locations in the bed as well as sides of the lined canal
b) in the bed of the canal
c) in the sides of the canal
d) anywhere in the canal
Answer: a
Clarification: Drainage relief pockets are provided with pressure relief valves filled with a graded filter containing gravel, coarse sand, and fine sand. They are provided at isolated locations in the bed as well as on the sides below the lining at suitable spacing (@ 15 to 20 m intervals).

6. The permeability of lining is also governed by the depth of water in the canal and type of subgrade soil.
a) True
b) False
Answer: a
Clarification: The permeability of lining may decide the quantum of seepage loss from a canal. The seepage losses from a canal for a particular area will depend on the local conditions such as the values of land and water, population intensity, etc.

7. Pressure relief valves may help in ___________
a) releasing the hydrostatic pressure
b) holding the hydrostatic pressure
c) increasing the hydrostatic pressure
d) may increase or decrease the hydrostatic pressure
Answer: a
Clarification: Pressure relief valve is a flap valve opening upwards into the canal. It helps in releasing the hydrostatic pressure as soon as the differential head exceeds the safe pressure. These valves open out as soon as the differential pressure goes beyond 10 cm.

8. Pipe drains run _______________
a) longitudinally on the bed and transverse to the length of canal on the side slopes
b) longitudinally to the length of the canal on the side slopes and transverse to the bed
c) longitudinally to the length of the canal
d) transverse to the bed
Answer: a
Clarification: Provision of open-jointed pipe drains is one of the methods of drainage arrangements. It will run longitudinally on a trench excavated below the lining on the canal bed along the length of the canal and transverse to the length of the canal on the side slopes.

9. Which of the following statement is wrong about the requirement of good lining?
a) The lining should be able to withstand the differential sub-soil pressure
b) Brick lining, concrete lining or precast slab lining can be easily repaired as compared to cast-in-situ concrete lining
c) The hydraulic efficiency generally reduces with time
d) Brick tile lining may provide better abrasion resistance than cement concrete and boulder lining
Answer: d
Clarification: A canal may have to transport a considerable amount of sediment load which damages the lining by abrasion. Cement concrete and stone boulder linings provide better abrasion resistance as compared to the brick tile lining.

10. Which type of lining is adopted when the channels have become stable and no danger of scouring is expected?
a) Brick lining
b) Single burnt clay tile lining
c) In-situ cement concrete lining
d) Flexible membrane lining in the bed and rigid lining on the sides
Answer: d
Clarification: The burnt clay tile lining is to be adopted at places where aggregates for the manufacture of concrete are not available economically. The brick lining is used where seepage considerations are important. In-situ cement concrete lining is provided when the canal has a bed width greater than 8 m.