Irrigation Engineering Multiple Choice Questions on “Canal Irrigation System – Alignment”.
1. Which type of canal does not need cross drainage structures?
a) Side Slope Canal
b) Contour Canal
c) Watershed Canal
d) Field Channel
Answer: a
Clarification: Side slope canal is that type of canal which runs perpendicular to the ground contours, i.e they run parallel to natural drainage flow and do not intercept the drainage channels and therefore avoiding the construction of cross drainage structures.
2. What is the name given to the junction of two streams?
a) Ridge
b) Area of Mixture
c) Merging
d) Area of Mingling
Answer: a
Clarification: The dividing line between the catchment areas of two streams is called ridge or watershed. The main watershed between two streams divides the drainage area of the two streams.
3. On flatlands what type of canal alignment is used?
a) Side Slope Canal
b) Contour Canal
c) Watershed Canal
d) Field Channel
Answer: c
Clarification: For flat lands, the slopes are relatively flat and uniform and it is very easy, and advantageous to align canals along watershed. Therefore the name of the alignment is watershed canal.
4. A canal aligned on the watershed saves the cost of constructed cross drainage works.
a) True
b) False
Answer: a
Clarification: By aligning a canal on the ridge, helps to irrigate the land on both sides of the canal. Moreover, the drainage flows away from the ridge, this gives an advantage in a way that the drainage does not cross a canal aligned on the ridge. Therefore the cost of construction of cross drainage works is reduced.
5. Which type of canal is most useful in hilly areas?
a) Side Slope Canal
b) Contour Canal
c) Watershed Canal
d) Field Channel
Answer: b
Clarification: The idea of watershed canal in hilly areas is does not work because it is highly uneconomical, since the river flows in valley below the ridge. And the watershed may be hundreds of meters above the river.
6. Contour canal can irrigate only on one side of the canal.
a) True
b) False
Answer: a
Clarification: In this canal the river slope is much steeper than the canal bed slope so therefore the canal encloses more and more area between itself and the river. It should be noted that more fertile lands are located at the lower levels. In other words we can say contour canal irrigates only on one side as the other side is higher.
7. What type of canal necessitates construction of cross drainage works more than any other types?
a) Side Slope Canal
b) Contour Canal
c) Watershed Canal
d) Field Channel
Answer: b
Clarification: In this contour canal the drainage of the river flow is always perpendicular to the ground contours, and this would certainly require crossing of natural drains and streams, which necessitates the construction of cross drainage structures.
8. What type of canal alignment does the diagram represent?
a) Alignment of Side Slope Canal
b) Alignment of Contour Canal
c) Alignment of Watershed Canal
d) Alignment of Field Channel
Answer: c
Clarification: The image indicates an alignment of canal perpendicular to the ground contours. So, therefore the fitting example of this type of alignment is alignment of side slope canal.
9. Which type of alignment does the given figure represent?
a) Alignment of Side Slope Canal
b) Alignment of Contour Canal
c) Alignment of Watershed Canal
d) Alignment of Field Channel
Answer: b
Clarification: The figure shows a river flowing in a hill area, and we can observe that a canal is aligned along the contours of the area. The canal is connected to the river by head works. So, from these points we can conclude or say that it an alignment of contour canal.
10. Which type of canal is the farmer’s responsibility?
a) Contour Canal
b) Side Slope Canal
c) Watershed Canal
d) Field Channel
Answer: d
Clarification: The maintenance of field channel is the responsibility of the farmers because this channel is laid along the field boundaries and supply water to the fields to meet their requirements.
11. Which type of canal need syphons?
a) Side Slope Canal
b) Contour Canal
c) Watershed Canal
d) Field Channel
Answer: c
Clarification: The alignment of watershed canal should run in areas where there homes, sacred places etc, and does not run in loops of the ridge line but run in straight. So, for these depressions in the ridge line necessitates construction of viaducts or syphons to maintain the canal fixed supply level.
12. If a looping is present in the ridge line they how can that area be irrigated with?
a) Distributary
b) Tributary
c) Weir
d) Canal
Answer: a
Clarification: The alignment of watershed canal does not run along the loops of the ridge line, but instead they run in straight line leaving a small area between the alignment and the looped ridge line. This area can be irrigated with help of a distributary which starts from the starting of the loop of the ridge line and runs along the ridge line and finally joins the alignment at the end of the loop.