chapter 4:- Water recourses.
Q1. Give two main reasons why water scarcity occurs in India?
Ans. two main reasons why water scarcity occurs in India are:-
- increasing demand of water for domestic and industrial uses.
- lack of watershed Management
- rainfall is erratic and unreliable
(Write any two)
Q2. Mention two advantages of rainwater harvesting?
Ans. two advantages of rainwater harvesting are:-
- are prevents wastage of water.
- reduces soil erosion.
- recharge groundwater resource.
( write any two)
Q3. What do you mean by rainwater harvesting and mention any two methods of rainwater harvesting?
Ans. rainwater harvesting is a technique of increasing the recharge of groundwater by capturing and storing rainwater.
two methods of rainwater harvesting in India are:-
- surface runoff harvesting.
- rooftop water harvesting.
Q4. difference between surface water and groundwater mention two reasons to explain as to why we are facing water scarcity in recent time.
Ans.
| Surface water | Ground water |
| Water found in lakes, rivers and streams is called surface water. | Water trapped under the Earth's surface is called groundwater. |
| drawn into the public water supply for the human consumption. | pumped out of the ground after drilling a deep well. |
| includes the solid form of water snow and ice. | include soli water. |
two reasons why are we facing water scarcity are:-
- efficient use of water for agriculture.
- reduction and traditional water recharge in areas.
- pollution of water
- great misuse or over exploitation of water.
( write any two)
Q5. What are the advantages and disadvantages of rainwater harvesting?
Ans. advantages of rainwater harvesting are as follows:-
- it is absolutely free to use and clean source of water.
- it is environment friendly.
- it is excellent for irrigation.
- it reduces the use of groundwater.
disadvantages of rainwater harvesting are:-
- The expenses that cannot be afforded by some people.
- Rainwater harvesting system is all dependent on the climate so it is unpredictable.
- high cost of maintenance regularly.
- The storage is limited hence not much water can be stored.
Q6. why is well irrigation a popular mean of irrigation give two reasons to support your answer?
state the significance of rainwater harvesting.
Ans. there is still popular as it is cheap easy to construct occupies a small area control of water is in the hands of the farmer can be dug at any convenient place independent source of irrigation.
rainwater harvesting helps to meet the increasing demand of water, helps to check the surface runoff that chokes the drain, recharge groundwater resources, reduce soil erosion, raise underground water table.
Q7. give reasons for each of the following:-
- inundation canals are being converted into perennial canals.
- groundwater reserves are depleting at a fast rate.
- drip irrigation reduces loss of water through evaporation.
Ans. reasons for each of the following a given below:-
- integration Canal provides water only during rainy season. they are solely dependent on bane for an aggregate higher region.
- it is so due to lowering of the water table reduction of water in streams and lakes digital ocean of water quality and pumping groundwater.
- reduces the loss of water through evaporation because it supplies the water to the roots of the plants slowly through pipe, valve and tubing.
Q8. Where are time most widely used in India and why?
Ans. widely used in Andhra Pradesh Tamil Nadu and Karnataka.
thanks are mainly used in South India because:-
- the region of South India is uneven heart and consists of Rocky surface with natural depression.
- rainfall in seasonal and heavy.
- due to hard underlying rocks the surface is a serious and do not relocate water beneath the Earth's surface .
Q9. Give two advantages and disadvantages of tubewell have over surface well?
Ans. Advantages are:-
- are it is able to easily get a larger agricultural land.
- large amount of underground water is easily available.
- It is reliable during the dry season when the surface water rises up since the tube well is drilled Deep up to the permanent water table.
disadvantages are:-
- It is costly as it requires a regular supply of electricity.
- irrigation is not possible if the underground water level is low.
- excessive use of tubewell leads to lowering of groundwater level.
Q10. The north plain of India is found suitable for Canal irrigation give reason?
Ans. Canal irrigation is popular in northern plains because it is perennial river and land is soft enough for Canal to be constructed from river to the fields.