Water Resources Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What are water resources?

A

The term water resources refers to any of the entire range of natural waters that occur on earth and are of potential use to living beings.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is surface water?

A

Water on land as a result of precipitation or seepage from underground which forms streams, lakes, rivers and ponds flowing on land which finally joins the sea.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is ground water?

A
  • Water which seeps through the cracks and crevices under the surface of the land is known as ground water.
  • It remains in the soil, subsoil or bedrock.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Define an aquifer

A

An underground stream that is saturated with water and transmits water readily is known as an aquifer.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Expand CGWB

A

Central Ground Water Board

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why do we need to conserve water?

A
  • Overexploitation of groundwater leads to reduction in water table.
  • Loss of vegetation causes drought and leads to reduction of rainfall & water-table.
  • Increase in population results in water scarcity
  • Water resources are polluted and can hardly be used w/o adequate treatment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is rainwater harvesting?

A
  • Rainwater harvesting is the process of increasing recharge of groundwater by capturing and storing rainwater locally in sub surface water reservoirs.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What activities does rainwater harvesting include?

A
  1. Harvesting surface and ground water
  2. Prevention of losses of water through evaporation and seepage.
  3. All other hydrological studies and engineering for water conservation.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are objectives of rainwater harvesting?

A
  1. Meeting the ever increasing demand for water
  2. Reducing run-off which chokes the drains.
  3. Avoiding flooding of roads.
  4. Augmenting the groundwater storage and raise the water table.
  5. Reducing groundwater pollution.
  6. Improving quality of groundwater
  7. Reducing soil erosion.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Name the various storing mechanisms in different parts of the country.

A
  1. Khatri/Kuhl - Western Himalayas
  2. Baolis/Dighis - Gangetic Plains
  3. Johads - Central India
  4. Bhandaras/Kere - Deccan Plateau
  5. Surangam - Western Ghats
  6. Korambu - Eastern Ghats
  7. Zing - Ladakh
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a watershed?

A

Watershed is an area that draining to a common point. This makes it an ideal unit for conservation of both soil and water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is watershed management?

A
  • Watershed management refers to the efficient management of both the surface and the groundwater resources.
  • It includes prevention of run-off as well as storage and recharge of groundwater by various methods like percolation pits, recharge wells, bore wells, dug wells, etc.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why do we have acute shortage of water in India?

A
  • Not cared to conserve water
  • Rainfall in India occurs in short spells of high intensity.
  • Most of the rain falling on the surface tends to flow away rapidly.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are elements of water harvesting?

A
  1. Catchements
  2. Conduits
  3. Storage Facility
  4. Recharge Facility
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is catchement?

A

The catchment of a water harvesting is a surface which receives rainfall directly.

Examples
- courtyard of a building
- paved area like terrace
- unpaved area like open grounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are conduits?

A

Conduits are the pipelines or drains that carry rain water from the catchment or rooftop to the harvesting system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Examples of materials that conduits are made of:

A
  • polyvinyl chloride PVC
  • asbestos
  • galvanized iron
  • commonly available materials
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are storage facilities for rainwater?

A

Rainwater can be stored in any commonly used storage containers like RCC, masonry or plastic water tanks

19
Q

Give examples of recharge facilities for rainwater

A
  • borewells
  • dug wells
  • recharge pits
  • percolation pits (soakaways)
  • recharge trenches
  • permeable surfaces
  • porous tiles
20
Q

What are Borwells and dugwells?

A
  • used to raise the underground water table
  • Rainwater is collected on rooftop of building which is then diverted by drain pipes to filtration tank.
  • From there it close into a bore well or dug well.
21
Q

what are recharge pits?

A

Recharge pits are excavated into the ground line with break or stone walls with opening at regular intervals

22
Q

What are percolation pits or soakaways?

A

Percolation pits are bored holes of 30 cm diameter drill in the ground up to a depth of 3 to 10 m

23
Q

What are recharge trenches?

A

Recharge trenches are excavated on ground and refilled with porous media like pebbles boulders break to harvest surface runoff

24
Q

How are permeable surfaces used to recharge groundwater?

A

Permeable surfaces like patches of grass are used to retain a large proportion of the rainwater falling on it only 10 to 15% as run off.

25
Q

How can we store water for direct use?

A
  • By help of underground RCC installed in basement or outside the building
  • By help of Pre fabricated tank such as PVC
  • Tanks must have overflow system which may be connected to the drainage
26
Q

Generally run of from only pave surfaces is used for storing give reason.

A

Since it is relatively free of bacteriological contamination

27
Q

Define rooftop rainwater harvesting

A

Rooftop rainwater harvesting is the process of water harvesting in which rain water falling on a roof is diverted through drain pipes to the storage containers.

28
Q

GR: Water quality improves over time during storage in the tank.

A

because impurities settle down in the tank if the water is not disturbed and even pathogenic organisms gradually die out due to storage.

29
Q

Define irrigation

A

Irrigation refers to the process of watering of agricultural plants through artificial means such as wells, tanks, tubewells, etc.

30
Q

What is the need of irrigation in India?

A

1. Uncertainty of Rainfall:
Rainfall in India is highly irregular in place and time, and rainfall in India occurs in short spells of high intensity.

2. Uneven Distribution of Rainfall
- Rainfall distribution in India is quiet uneven
- Rainfall occurs from june to sept brought by SW Monsoon winds.
- Some places get very heavy rainfall while some places get very less rainfall.

3. Crop Requirements:
- grain crops require more water during the time earheads are formed.
- zaid crops (summer crops) are exclusively irrigated as monsoon does not occur at the time they’re grown unlike kharif and rabi crops.
- High Yielding Varieties require higher quantity of chemical fertilizers therefore need to be well-irrigated.
- Commercial crops like sugarcane require higher quantity of water.

4. Nature of soil.
- Amt. of Irrigation req Depends on nature of soil. Ex: clayey soils have high moisture retention, less irrigation, Sandy soil has less moisture retention capabilities hence drip irrigation is suited there.

5. Utilizing water effectively
- Many non-perennial rivers of central and southern India only have water during the monsoons

31
Q

State two advantages of Well irrigation.

A

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.

32
Q

What are the conditions required for drilling a tube well

A

• Level land and soft soil
• Large fertile area in the surrounding
• Availability of regular and cheap electricity to run the tube
wells.

33
Q

State two advantages of tube well irrigation.

A

• Independent source of water
• Brings up clean water
• It can irrigate a large area.

34
Q

What are the disadvantages of tube wells?

A

• 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.

35
Q

State two conditions necessary for tank irrigation.

A

• Presence of natural depressions
• Hard rock strata.

36
Q

State the disadvantages of tank irrigation.

A

• 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.

37
Q

What are the drawbacks of conventional methods of
irrigation?

A

• Large quantity of water is not properly utilized.
• Some area of land is utilized in preparing channels which
decreases effective area of cultivation.

38
Q

What is drip irrigation?

A

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.

39
Q

Give three reasons to justify the need to conserve water.

A

• 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.

40
Q

What is Rainwater harvesting?

A

Ans.Rainwater harvesting is collecting and storing rainwater for a
later use

41
Q

What is Watershed management

A

Ans.It refers to the efficient management and conservation of
both surface and groundwater resources.

42
Q

Why are perennial canals preferred over inundation canals?

A

Ans. Perennials canals have water throughout the year and two or
more crops can be grown.

43
Q

Why is canal irrigation more popular in Northern India?

A

• The rivers are perennial
• Presence of flat land
• Soft soil for easy digging.