Water Resources
Std 10 - Geography
Question and Answers
1. What is meant by Irrigation?
Ans. Irrigation refers to the process of watering agricultural
plants through artificial means from wells tanks tubewells and
canals for agricultural production
2. State the importance of Irrigation.
Ans.
Uncertainty of Rainfall
Uneven distribution of rainfall.
Crop requirement
Nature of the soil
Utilizes river water effectively
To maximize production.
3. State two advantages of Well irrigation.
Ans.
Wells are dug at a low cost.
Oxens which are kept for ploughing the land can be utilized
for drawing water from the wells at no extra cost.
4. What are the conditions required for drilling a tube well
Ans.
Level land and soft soil
Large fertile area in the surrounding
Availability of regular and cheap electricity to run the tube
wells.
5.State two advantages of tube well irrigation.
Ans.
Independent source of water
Brings up clean water
It can irrigate a large area.
6. What are the disadvantages of tube wells?
Ans.
Excessive use of water leads to depletion of ground water.
Expensive as it requires continuous supply of electricity.
It is useless if the water is brackish.
7. State two conditions necessary for tank irrigation.
Ans.
Presence of natural depressions
Hard rock strata.
8. State the disadvantages of tank irrigation.
Ans.
Tanks occupy a large area which could be used for growing
crops.
When monsoons fail tanks go dry.
Tanks are shallow so water gets evaporated.
9. What are the drawbacks of conventional methods of
irrigation?
Ans.
Large quantity of water is not properly utilized.
Some area of land is utilized in preparing channels which
decreases effective area of cultivation.
10. What is drip irrigation?
Ans. It is the system consisting of perforated pipes that are placed
between the rows of crops or buried along the root and gives
water directly to the crops.
11. Give three reasons to justify the need to conserve water.
Ans.
Overexploitation of underground water results in the
lowering of the water table.
The increase in population results in water scarcity.
Loss of vegetation causes drought and reduction in rainfall.
12. What is Rainwater harvesting?
Ans.Rainwater harvesting is collecting and storing rainwater for a
later use.
13. What is Watershed management?
Ans.It refers to the efficient management and conservation of
both surface and groundwater resources.
14. Why are perennial canals preferred over inundation canals?
Ans. Perennials canals have water throughout the year and two or
more crops can be grown.
15. Why is water harvesting needed?
Ans. In India there is shortage of water during the year . Rainfall in
India is of short spells of high intensity.Most of the rain falling on
the surface tends to flow away rapidly leaving very little for
recharge of groundwater.
16. Why is canal irrigation more popular in Northern India?
Ans.
The rivers are perennial
Presence of flat land
Soft soil for easy digging.
17. State two advantages of Rainwater harvesting.
Ans.
Recharge of groundwater
Conservation of water reduces surface runoff.
18. What are the demerits of canals?
Ans.
In some places where perennial unlined canals flow at the ground
level and between and between raised high banks, the water
table may reach the surface making the soil water logged.
In canal irrigation where water table is a few feet below the
ground, the alkaline salts come to the surface making the soil
unproductive.
19. Why is the world in severe danger of facing a water shortage in
the coming future?
Ans.
Most of our surface water is polluted by industrial
waste and sewage.
The indiscriminate use of fertilizers, chemicals and
pesticides has led to increasing ground water pollution.
20. Give Reasons –
A. Tank irrigation is preferred in peninsula India.
Ans. Due presence of natural depressions and hard rock
strata.
B. Irrigation is necessary despite the monsoon.
Ans. Indian monsoons are most uncertain. Late arrival or
early withdrawal of the monsoon affects crop production.
C. Tube wells are preferred over surface wells.
Ans. tube wells can irrigate a larger area and they are more
reliable during drought condition.
D. Inundation canals are being converted to perennial canals.
Ans. inundation canals are seasonal. They have water only
when the river is flooded. With the help of inundation canal
only one crop can be grown.
E. Tube wells are extensively used in Punjab and Haryana.
Ans. Since the land is soft it enables easy digging and also
availability of electric power.
F. The drip method of irrigation is the best among all modern
methods.
Ans. This method does not involve any loss of water through
seepage because water is supplied by a pipe to the root of
the plant. No water is lost through evaporation.
G. Traditional means of irrigation are still important in most
parts of India.
Ans. Traditional means of irrigation like wells, tanks and
canals are still important as they are cost effective. Whereas,
modern methods like drip and sprinkler are very expensive.
H. Sprinkler irrigation is practiced in arid and semi arid
regions.
Ans. To minimize the loss of water.
I. A tube well should be installed in a fertile and productive
region.
Ans. In these regions there is demand for irrigation and the
cost involved in the construction and operation of the tube
well can be recovered by increased farm production.
J. Cherrapunji receives heaviest rainfall and still suffers from
acute shortage of water.
Ans. This is because rainfall occurs in short spells of high
intensity, most of the rain falling on the surface tends to
flow away rapidly leaving very little for recharge of ground
water.
