AP State Syllabus 7th Class Social Important Questions 3rd Lesson Tanks and Ground Water
Question 1.
Differentiate between previous rocks and impervious rocks?
Answer:
Previous rocks:
Rocks that have cracks or pores in them and can contain water are called previous rocks.
Impervious Rocks:
Some rocks like granite, Kadapa limestone, are very compact and do not have pores in them. Water cannot enter into them. Groundwater usually accumulates above such rocks. Since the water cannot go beneath them, these are called impervious rocks.
Question 2.
Suggest two ways to restore the groundwater. (or)
Suggest any two measures that recharge the groundwater?
Answer:
The following measures are useful for recharging the groundwater.
- Check dams
- Percolation tanks
- Loose boulder structures
- Plantations on forest land and roadsides etc.
Question 3.
Tanks are declining in our times. What are the reasons for this in your opinion?
Answer:
The reasons for the deterioration in tanks is due to groundwater exploitation, progress in individual pits and pumps in tank management area, the collapse of village organizations, poor preservation, and the Green Revolution. Tank irrigation has declined over time because of the depression in the farming output.
Question 4.
Prepare a Pie-chart by using the given information.
a) Lakes-87% b) Swamps – 11% c) Rivers-2%
Answer:
Question 5.
‘If we draw more water than what percolates down, the groundwater will decrease over time. Finally, there may be little groundwater left for us”.
This has been happening during the last few years.”
Why do we overuse groundwater? How can we ensure that the groundwater level doesn’t decrease over time? Comment.
Answer:
We use under-ground water for domestic purposes, for industrial production purposes, for cleaning machines and for increase agricultural production, etc.
We can protect the underground water in the following ways.
- Dig the percolation tanks,
- Rainwater harvesting pits.
- Loose boulders.
- Increasing vegetative cover.
- Floods are often caused by a sudden increase in underground water.
All the above methods we should recharge the underground water. So water levels don’t decrease over time.
Question 6.
Study the paragraph and answer the following questions.
“During the last twenty or thirty years, the tanks have been neglected and have been allowed to break down. Repairs to the tanks, desilting, etc., have not been done regularly. People also have gradually taken over the tank land for building houses or for agriculture”.
Q. Do you agree with the statement that “human activities have caused the decline of tanks”? Explain Why?
Answer:
- During the last 20 years, the tanks have been neglected and have been allowed to break down.
- Repairs to the tanks, desilting, etc. have not been done regularly.
- People also have gradually taken over the tank land for building houses or for agriculture.
- As a result, in almost every part of the state, we see the sad state of dry tanks lying uncared for.
Question 7.
Explain the reasons for the percolation of Groundwater and write its effects on Mankind.
Answer:
- If we recharge the groundwater we will get water for a long period of time.
- It is useful for multiple cropping.
- It is useful availability of water in dry seasons also for drinking purpose.
- It is useful for our animal wealth in the summer season and grass is also available.
- So development will be present.
Question 8.
“We should remember that no one person owned the tanks and they belonged to all people of the village. Tanks benefited not one or two people but the entire village.” How are Tanks benefited all people? Comment on it.
Answer:
- The tanks helped the people not only in giving them and their animals drinking water but also in irrigating their fields in such a way that even in drought years they could raise at least some crops.
- The Tanks also helped to increase the water level in the wells nearby.
- The tanks helped to prevent the run-off of rainwater and the erosion of topsoil.
- Every year people would collect tank silt and apply it to their field to the fertile soil.
- We should remember that no one person owned the tanks and they belonged to all people of the village.
Question 9.
Explain the objectives and importance of the Andhra Pradesh Water, Land, and Trees protection Act?
Answer:
- AP WALTA Act means Andhra Pradesh Water Land and Trees Act.
- Its objectives,
- It promotes water conservation.
- Its protection of forests.
- It promotes the construction of check dams.
- It encourages the setting up of watershed programs.
Question 10.
How were the tanks built?
Answer:
- The tanks were sometimes built by a king, sometimes by a military leader or nayaka, or often by the people of the village themselves.
- Usually, every village preserved the memory of those who were responsible for building the tank through stories or temples, or festivals.
- In building the tank, everyone in the village contributed to expenses and labour.
- All people of the village together maintained the tank by repairing the tank bund (wall) or removing silt from the tank bed.
- They also took care so that no one dirtied or stopped the water flowing into the tank.
- They also appointed a person to regulate the use of the water from the tank.
- The tanks were usually built by building a strong wall of stones and mud across a small stream in such a way that with a wall on just one side a large lake could be formed.
Question 11.
How did the tanks help?
Answer:
- The tanks helped the people not only in giving them and their animals drinking water, but also irrigating their fields in such a way that even in drought years they could raise at least some crops.
- The tanks also helped to increase the water level in the wells nearby.
- After the rains have stopped and the tank water decreased, the tank bed could be used for raising some crops.
- Most important thing is that the tanks helped to prevent the runoff of rain water and the erosion of topsoils.
- Every year people would collect tank silt and put it in their fields to fertilize the soil.
- Tanks belonged to all people of the village. Thus they benefited not one or two people but all people of the village.
- To this day most of the villages in the Telangana and Rayalaseema regions have at least one or two major tanks.
Question 12.
Explain the decline of tanks in our times.
Answer:
- During the last twenty or thirty years, the tanks have been neglected and have been allowed to break down.
- Repairs to the tanks, desilting, etc., have not been done regularly.
- People also have gradually taken land for building houses or for agriculture.
- As a result in almost every part of the state, we see the sad state of dry tanks lying uncared for.
- Instead of caring for the tanks, we have been digging deeper and deeper tube wells at great expense.
- But they only benefit a few and in the long run deplete water resources. On the other hand, tanks build resources for all.
Question 13.
Mention the differences between previous rocks and impervious rocks.
Answer:
Previous rocks | Impervious rocks |
1) Rocks that have cracks or pores in them and can contain water are called previous rocks. | 1) Some rocks like granite. Kadapa limestone is very compact and doesn’t have pores in them. Water cannot enter into them. Groundwater usually accumulates above such rocks, Since the water cannot go beneath them, these are called impervious rocks. |
2) In Andhra Pradesh we have a few districts like Prakasam where such rocks as sandstones are found. | 2) Most of the rocks underlying the soil in our state are of this kind. |
Question 14.
What are the minerals dissolved in the groundwater?
Answer:
- Minerals come from the rocks and soil underneath.
- Hence depending upon the minerals which mix with the water, the taste and nature of water change.
- In many mandals of our state, there is an excess quantity of certain minerals like Sodium, Fluoride, Chloride, Iron, Nitrate, etc.
- Drinking such water is not good for our health and can cause diseases that affect our bones, teeth, etc.
Question 15.
In what way can we increase or recharge groundwater?
Answer:
- Water flows swiftly on the naked ground, which has no cover of trees or grasses as there is nothing to stop the flow. However, if the flow of the rainwater is checked by vegetation or bunds, then there is a greater possibility of this water percolating into the soil to join the groundwater.
- Grasses are planted on the hill slopes from where a stream starts and small check dams are also built across streams to store water for a longer time. All this helps to increase or recharge groundwater.
- Over the last few years, great efforts have been undertaken to ‘harvest’ rainwater by these means.
- These measures are usually taken for a stream (or) river. Such efforts are called ‘Watershed development projects.
- Under these projects trees and grasses are planted on the hill slopes from where a stream starts and small bunds are built across small streams to stop the flow of water.
- Small check dams are also built across streams to store water for a long time.
- All this helps to increase or ‘recharge’ groundwater.
Question 16.
“Sometimes the water is sweet and sometimes salty.” Explain the reasons for this.
(or)
The groundwater in some areas is salty and in some areas it is sweet. Why?
Answer:
This difference is because of the minerals which are dissolved in the groundwater which is usually mixed with many minerals. These minerals come from the rocks and soils underneath. Hence, depending upon the minerals which mix with the water, the taste and nature of water change. In our state many mandals in Prakasam, Kadapa, and Ananthapur there is an excess quantity of certain minerals like Sodium, Fluoride, Chloride, Iron, Nitrate, etc. Drinking such water is not good for our health and can cause diseases that affect our bones, teeth, etc. In such situations, the drinking water should be properly treated to remove the excess minerals.
Question 17.
Why is the water polluted?
Answer:
- Many times water is polluted due to the excessive use of fertilizers and pesticides or poor: drainage.
- Sometimes the water is polluted by animals and human beings.
- Even the ashes of the dead persons and dead animals are thrown into rivers.
- In villages, people wash their clothes on the banks of rivers and bathe their cattle there.
- Sometimes the water is polluted by chemicals released from industries and factories reached of the rivers through the drainage system.
Question 18.
What is the need for groundwater sources in India?
Answer:
- India is an agricultural country. India needs sufficient water to the crops.
- Seasonal occurrence of rainfall
- Increase of agricultural production through multiple cropping systems
- To safeguard areas against droughts
- To utilize effectively the available water resources
- Today’s generation has received water from the past as a sacred asset.
- We should give it to the future generation just as we received it.
- We should also develop ways of using and conserving water in a restrained manner. Otherwise future generations will fight destructive wars over water and we will be responsible for it.
Question 19.
Can you recall the wells and tube wells in Penamakuru and Salakamcheruvu villages you studied in class VI?
Answer:
Yes, I can recall. The wells in Penamakuru have water at a depth of 15 to 25 feet. The wells in Salakamcheruvu have water at a depth of 100 to 125 feet. They are borewells.
Question 20.
Can you think of ways in which groundwater can be used less without wastage?
Answer:
Water quickly flows into streams and into rivers. However, if the flow of the rainwater were to be checked by vegetation or bunds, then there would be a greater possibility of the water percolating into the soil to join the groundwater.
This is why vegetation like trees and grasses and bunds are used to enhance groundwater. Over the last few years, great efforts have been made to ‘harvest’ rainwater by these means. These measures are usually taken for a stream or river. ” Such efforts are called ‘watershed development projects. Under these projects trees and grasses are planted on the hill slopes from where a stream starts. Also, small bunds are built across small nullahs and streams to stop the flow of water. Small check dams are also built across streams to store water for a longer time.
Question 21.
Explain the decline of tanks in our time.
Answer:
During the last twenty or thirty years, the tanks have been neglected and have been allowed to break down. Repairs to the tanks, desilting, etc., have not been done regularly. People also have gradually taken over the tank land for building houses or for agriculture. As a result in almost every part of the state, we see the sad state of dry tanks lying uncared for. Instead of caring for the tanks, we have been digging deeper and deeper tube wells at great expense. But they only benefit a few and in the long run deplete water resources. On the other hand, tanks build resources for all.
Question 22.
Can you think of a way in which the groundwater in your village can be used equitably so that all families – including those who do not have any land get water? Draw up such plans and discuss them in the class.
Answer:
The village Panchayat should dig a borewell, and pump the water to a tank, and then the water would be supplied to the villagers. Then only the water can be used equitably.
Question 23.
Project: Prepare a report with the following details about the tank in your village or town.
a. Prepare a sketch map of the tank and its nearby areas.
Answer:
b. Find out from where the water comes into the tank and where the excess water goes.
Answer:
Tanks get water from rain. As they are in the low-lying areas they get water when it rains. In times of flood, they overflow and the excess water goes out through drains.
c. Find out the name of the river or stream across which it has been built or the names of the hills near which it has been built.
Answer:
Godavari river / Eastern ghats.
d. Find out what the tank bund is made of and who maintains it.
Answer:
Tank bund is made of heavy stones. A person named ‘Ramulu’ maintains it.
e. Find out who built the tank and when it was built.
Answer:
The tank was built by Smt. Raja Rajeswaramma in 1908.
f. Prepare an illustration of the tank and various things around it or get photographs of the tank.
Answer:
The tank is in Bhimavaram in W.G. District. During the British rule Smt. Raja Rajeswaramma dug the tank for the purpose of drinking water. At the time of opening the tank, she performed ‘Santhi Homa’. She made ‘Annadaana’ also at that time. In those days she spent Rs. 2000/- for all these works. But later it was not in use. In recent years, Bhimavaram municipality is supplying drinking water through ‘Nallas’. Now many people occupied the surroundings of the tank and build shops and temples. Some rich people and politicians are planning to take over the land of the tank for their personal uses.
g. Find out what crops are grown, who controls the water, and how it is regulated and note down.
Answer:
It was a drinking water tank. Nobody is regulating it at present.
Question 24.
Look at the figure given below and answer the following questions:
a. The groundwater level is ………. meters below the ground level.
Answer:
5
b. In summer if the water level goes down to 10 meters below the ground level which of the four wells will go dry?
Answer:
Well 2 and well 3.
c. Which well will have maximum water available?
Answer:
Well-1.
Question 25.
Look at the figure given below and answer the following questions.
a. Can you find how water entered the level below the impervious rock and reached the crack in the rock below?
Answer:
The top portion of these rocks is broken and they carry water. Many of these rocks also have deep cracks going down to 50 or 100 meters in depth. These cracks too contain water.
b. During summer which well will go dry first? Give your reasons.
Answer:
Well ‘W’ will go dry first. The usage of the water will be high from this well.
c. Will there be water in the well even if there is no crack in the rock?
Answer:
Yes, there may be a chance.
Question 26.
Read the following para and answer the questions.
In many mandals the predominant rocks are not granites but rocks of the Kadapa type of limestones. They are also hard but are greatly broken and have a lot of gaps between them allowing water to accumulate in them. In these rocks, water is usually available between three to fifteen meters below the ground level. Wells are therefore dug up to 16 meters deep.
The areas adjacent to the great rivers like the Krishna and the Godavari have deep layers of sand and silt. The water level here depends upon the water in the river. Usually, there is plenty of water. It is nearly five to seven meters below the ground in these areas and it is very easy to dig wells in them.
1. Which rocks are too hard?
Answer:
Rocks of the Kadapa type of limestones
2. Which rocks have a lot of gaps between them?
Answer:
Rocks of Kadapa type of limestone
3. Which areas have deep layers of sand and silt?
Answer:
The areas adjacent to the rivers like the Krishna and Godavari have deep layers of sand and silt.
4. Is it very easy to dig wells in them?
Answer:
Yes, it is easy.
5. How is the water level in these areas?
Answer:
The water level depends upon the water in the river. Usually, there is plenty of water. It is nearly five to seven meters below the groundwater in these areas and it is very easy to dig wells in them.
Question 27.
What are the uses of groundwater?
Answer:
- Groundwater, like the rivers, is the common resource of all people and not just of those who have landed over aquifers.
- However, at present, it is being used only by those who have such lands.
- Those who own land over aquifers tend to overuse the water which decreases the water table for all neighboring people.
- Some of them dig deeper tube wells which causes a further decline in water level.
- As a result, the wells in the neighborhood are going dry.
- If we use the groundwater as a common resource and in a restrained manner, we can ensure that everyone is able to benefit from them.
- In fact, after a few years, even those who dig deeper tube wells will not have any water left to pump.