Test: Irrigation Engineering- 1

20 Questions MCQ Test Mock Test Series of SSC JE Civil Engineering | Test: Irrigation Engineering- 1

Attempt Test: Irrigation Engineering- 1 | 20 questions in 12 minutes | Mock test for SSC preparation | Free important questions MCQ to study Mock Test Series of SSC JE Civil Engineering for SSC Exam | Download free PDF with solutions

Wetted perimeter of a regime channel for discharge of 144 cumec as per Lacey’s theory will be:


Wetted perimeter is given by 

Where Q = discharge in cumec

Wetted perimeter 


If the electrical conductivity of water is in between 750 to 2250 micro mhos/cm at 25oC, then it is classified as:


Electrical Conductivity (EC):

It is the reciprocal of the Electrical Resistivity. Quantitively the electrical resistivity is the resistance, in ohms, of a conductor, metallic or electrolytes, which is 1 cm long and has a cross-sectional area of 1 cm2 at 25oC.


EC = Reciprocal ohms/cm or mhos/cm.


A canal which is aligned at right angles to the contour is called


Watershed canal: The canal which is aligned along any natural watershed is called a watershed canal.

Contour canal: A contour canal is an artificially-dug navigable canal which closely follows the contour line of the land it traverses in order to avoid costly engineering works such as boring a tunnel through higher ground, building an embankment over lower ground, or constructing a canal lock (or series of locks) to change the level of the canal. Because of this, these canals are characterized by their meandering course.

Side slope canal: A side slope canal is that which is aligned at right angles to the contours i.e along the side slopes.

Branch canal: An offtakes from the main canal is known as branch canal.


The discharge passing over an ogee spillway is given by _______, Where, L is an effective length of spillway crest and H is the total head over the spillway crest including velocity head.


Dischage over an Ogee spillway is given by:

He = Total head upstream of the crest.

L = crest width

Cd = coefficient of discharge

C = constant, which is equal to


The sodium carbonate lining in canal consist of at least


Sodium carbonate lining consists of 10% clay and 6% sodium carbonate. This lining is not durable. Asphalt lining is prepared by spraying asphalt (i.e. bitumen) at a very high temperature (about 1500C) on a subgrade to a thickness varying from 3 mm to 6 mm.


The berms when fully formed:


Berm: The narrow strip of land at the ground level between the inner toe of the bank and the top edge of the cutting is known as berm. The berms provide additional strength to banks and thus make it safe against breaches. The berms when fully formed performed the following functions:

i) Provide a bigger water way

ii) Protect the bank from erosion because of wave action

iii) Reduce the absorption losses and prevent leaks

iv) Provide a scope for future widening of the canal

v) Bring the saturation line within the embankment


Critical velocity of flow (Vo) given by Kennedy is 

Where, m = critical velocity ratio, D = Depth of water over the bed portion of a channel in meters


Critical velocity of flow (Vo) given by Kennedy is 

Where, m = critical velocity ratio

D = Depth of water over the bed portion of a channel in meters


Which of the following are the main causes of water logging:


A land is said to be waterlogged when the air circulation is stopped in the root zone of the plant due to the rise in water table.

The main causes of waterlogging are as follows:

i) Inadequate drainage facilities

ii) Over and Intensive irrigation

iii) Presence of impermeable strata

iv) Nature of soil

v) Seepage from canals

vi) The topography of the land


A field of 500 hectares is to be irrigated for a particular crop having 100 days base period. The total depth of water required by the crop is 100 cm. Calculate the duty of the water (in hectares per cubic metre).


Using the relation 

Δ → depth of water required (cm)

D → Duty (hectares per cumec)

B → Base period (days)

Δ = 100 cm,   B = 100 days

D = 864 hectares per cumec


For smooth entry, the regulators are aligned at an angle of “x” to the water. The value of “x” is:


The irrigation works constructed for regulating the supply of irrigation water are called regulators.

For smooth entry these regulators are aligned at an angle of 110° to the water.


The relation for discharge over a rectangular crest of a sarda fall is

Where, L = Length of crest in meters

B = top width of the crest in meters

H = depth of water in meters


Discharge over a rectangular crest of a sarda fall is given by:

Where, L = Length of the crest in meters

B = top width of the crest in meters

H = depth of water in meters


Lysimeter is used to measure:


Lysimeter is used to measure evapotranspiration. By recording the amount of precipitation that an area receives and the amount lost through the soil, the amount of water lost to evapotranspiration can be calculated.


The unit of duty is:


The duty is defined as area irrigated in hectare when unit discharge flows for a base period B. It is measured in hectare per cumec.


Lacey’s regime theory is not applicable to:


If a channel is excavated with smaller width and flatter bed slope, then flow takes place and bed slope increases due to deposition of silt. With increase in bed slope, the depth of channel may also vary but width of channel remains same because channel is usually cohesive and resists erosion.

Final Regime: This is the ultimate state of regime attained by channel when the slope, width and depth are also adjusted as per requirement. Resistance of sides are overcome due to continuous action of water.

True Regime:  Practically, true regime is never attained.

Lacey’s theory is not applicable to initial regime. True regime is not attained, hence this theory is applicable to final regime channels.


A super passage is:


The structure build at the head of the watercourse so as to connect it with a minor or a distributor channel is known as:


The success of any irrigation enterprise depends on the efficiency of distributing sufficient supply of water to the irrigator. Each irrigator has to receive certain quantity of water proportionate to his extent in a canal system at the proper time to ensure him a good crop. This distribution of water is carried out by means of outlets otherwise called modules. Hence, proper design of an outlet, is of most importance not only to the canal engineer but to the irrigator also.


If D is the depth of scour below original bed, then the width of launching apron is generally taken as: 


Heavy scour of the river bed at curved heads and shanks of guide banks can cause undermining of stone pitching thereby resulting in failure of guide banks. Such a failure can be prevented by providing launching apron beyond the toe of guide banks. The width of launching apron is generally taken as 1.5D.


Which of the following is Rabi crop?


The rabi crops are sown around mid-November, after the monsoon rains are over, and harvesting begins in April/May. The crops are grown either with rainwater that has percolated into the ground, or with irrigation.

The major rabi crop in India is wheat, followed by barley, mustard, sesame and peas.


Which one of the following is the purpose of providing the downstream sheet pile in a barrage?


Water that percolates through earth dams and their foundations can carry soil particles that are free to migrate. The seepage forces tend to cause the erodible soil to move towards the downstream face of the dam and can cause failure of the dam which is known as piping failure. Downstream sheet pile is used to control failure due to piping.


Which of the following spillway gates cannot be seen from a distance, when lowered?

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