Irrigation Engineering Multiple Choice Questions on “Water Logged Reclamation – Surface or Open Drainage”.
1. The land is made to be sloped towards the ditches.
a) True
b) False
Answer: a
Clarification: Open ditches are constructed in fields to remove the excess rain water falling in the ground or excess irrigation water applied to the fields. So, therefore for collection of these waters the land is sloped towards these ditches.
2. How many types of structures can be constructed in the fields to remove excess waters?
a) 5
b) 2
c) 3
d) 4
Answer: c
Clarification: Structures like open ditches, fields drains, and other related structures like artificial pipes etc can be constructed in the fields to remove excess waters from heavy rainfalls and excess irrigation.
3. What is the name given to the drains used in depressions?
a) Shallow Surface Drains
b) Deep Surface Drains
c) Open Drains
d) Drains
Answer: a
Clarification: Shallow surface drains are those types of open drains constructed in depressions on the fields to remove excess irrigation water, and storm water.
4. Shallow surface drains are connected to outlet drains.
a) True
b) False
Answer: a
Clarification: The shallow surface drains are in turn connected to the outlet drains, which are large enough to carry the maximum flood water of the catchment area from the shallow drains, and even from underground tile drains.
5. What is the cross sectional shape of shallow surface drains?
a) Triangular Shape
b) Circular Shape
c) Rectangular Shape
d) Trapezoidal Shape
Answer: d
Clarification: Since the shallow surface drains are designed to carry normal storm water and excess irrigation water. These are designed for normal runoff from the storm water, but we have to take excess irrigation into the account. So, for maximum discharge the shallow surface drains are given a trapezoidal cross sectional shape.
6. Which type of open drains would be fully operative only in rainy season?
a) Shallow Surface Drains
b) Deep Surface Drains
c) French Drain
d) Drains
Answer: b
Clarification: These drains carry both discharge from shallow surface drains and the seepage water from underground. To carry the seepage water from underground, a cunnette of about 0.6 m depth is provided at the center of the drain. The cunnette is lined void weed growth, and to withstand high velocities. It is fully operative only in rainy season because otherwise the flow will be confined in the cunnette only.
7. What structure is constructed to carry back into the underground?
a) Land Grading
b) Random Field Drains
c) Surface Inlet
d) Open Drains
Answer: c
Clarification: Surface inlets are the structures constructed to carry the pit water back into the subsurface. The materials used in the construction are cast iron pipe or manhole of bricks or monolithic concrete.
8. What type of system does the diagram represent?
a) Drains
b) French Drain
c) Deep Surface Drain System
d) Random Field Drain System
Answer: d
Clarification: This represents a series of depressions connected with shallow surface drains which are in turn connected to lateral and main outlet drains. So, therefore this diagram represents a system of random field drain system.
9. In surface inlet what is provided to deal with trash?
a) Cunnette
b) Beehive Grate
c) Surface Inlet
d) Blind Inlet
Answer: b
Clarification: The bottom of the surface inlet a concrete collar is provided around the intake onto the prevent growth of vegetation or weeds. And to prevent the trash from entering the tile a beehive grate is provided on the top of the riser.
10. Which type of drains is used for small quantity of waters removal?
a) Blind Inlet
b) Shallow Surface Drains
c) Deep Surface Drains
d) Open Drains
Answer: a
Clarification: When the water quantity to be removed from the pits or depressions is small, then a blind inlet or also named as French drain is constructed over the tile drain. These drains are constructed by back filling with graded materials in the trench of the tile drain.