Water Resources Flashcards
1
Q
What does the term ‘water resources’ refer to?
A
Any of the entire range of natural waters that occur on the earth and are of potential use to living beings
2
Q
Name the available water resources
A
- Oceans
- Rivers
- Lakes
- Groundwater
- Deep sub-surface waters
- Glaciers
- Permanent snowfields
3
Q
Give the distribution of water on earth
A
97% - Ocean water
3 percent left ->
- 3% - Polar ice caps
- 7% - Freshwater
- 7 percent left ->
- 66% - Groundwater
- 03% - Freshwater in rivers, lakes, streams
4
Q
What is surface water?
A
Water on land is the result of precipitation or seepage from underground which forms streams, lakes, rivers, and ponds flowing on land and finally joining the sea
5
Q
What is groundwater?
A
The water which seeps through the cracks and crevices under the surface of the land
6
Q
What is an aquifer?
A
An undergroundwater stream that is saturated with water and transmits water readily
7
Q
Where is groundwater found?
A
In the soil, subsoil, or bedrock. Most of it ultimately reaches the sea.
8
Q
India’s water resources account for how much of the world’s resources?
A
4 %
9
Q
What provisions does India have to account for extensive water resources?
A
- Vast coastline w/ indented coasts in some states
- Surface water - from rivers, lakes, ponds, tanks
- Groundwater resources
10
Q
Name the states which have vast surface water resources in the forms of lagoons and lakes
A
- West Bengal
- Kerala
- Odisha
11
Q
What is brackish water in certain states utilized for?
A
Fishing and irrigation of certain crops like paddy, coconut, etc
12
Q
State the reasons for the decline in groundwater levels in parts of India
A
- Irrigation
- Industrialization
- Increase in population
13
Q
State the reasons why we need to conserve water
A
- The overexploitation of groundwater often results in the lowering of the water table
- The loss of vegetation causes drought and reduction of rainfall and lowering of the water table
- Irrigation utilizes more than 90% of total freshwater
- The increase in population results in scarcity of water
- Our water resources are polluted & their water can hardly be used without adequate treatment
14
Q
State the methods of water conservation
A
- Rainwater harvesting
- Adopting water-saving technologies
- Encouraging watershed development
- Water recycling
- Preventing the pollution of water
15
Q
What is rainwater harvesting?
A
It is the process of increasing the recharge of groundwater by capturing and storing rainwater locally in sub-surface water reservoirs
16
Q
What do activities included in rainwater harvesting aim at?
A
- Harvesting surface and groundwater
- Prevention of losses through evaporation and seepage
- All other hydrological studies and engineering interventions, aimed at conservation and efficient utilization of limited water endowment of an area such as a watershed
17
Q
Give the main objectives of rainwater harvesting
A
- Meeting the ever-increasing demand for water
- Reducing the run-off which chokes drains
- Avoiding the flooding of roads
- Augmenting groundwater storage & raise water table
- Reducing groundwater pollution
- Improving the quality of groundwater
- Reducing the soil erosion
- Supplementing domestic water requirement during summer and drought
18
Q
Name the primary and secondary sources of water
A
Primary - rain
Secondary - rivers, lakes, groundwater
19
Q
Name the water-conserving mechanisms that our ancestors followed
A
- People harvested rainwater by collecting water from the rooftops and storing it in tanks built in their courtyards. From open community lands, they collected rainwater and stored it in wells
- They harvested water runoff by capturing water from swollen streams during the monsoon season and storing it in water bodies
- They harvested water from flooded rivers
20
Q
What was the water receptacle called in Western Himalayas?
A
Khatri or Kuhl
21
Q
What was the water receptacle called in the Gangetic Plains?
A
Baolis or Dighis
22
Q
What was the water receptacle called in Central India?
A
Johads
23
Q
What was the water receptacle called in Ladakh?
A
Zing
24
Q
What was the water receptacle called in the Eastern Ghats?
A
Korambu
25
What was the water receptacle called in the Deccan Plateau?
Bhandaras or Kere
26
What was the water receptacle called in the Western Ghats?
Surangam
27
What is the annual rainfall of India?
1,170 mm (46 inches)
28
what is the world average of India?
800 mm (32 inches)
29
Why do places even like Cherrapunji suffer from acute shortage of drinking water?
Rainfall in India occurs in short spells of high intensity. Due to such intensities and the short duration of heavy rain, most of the rain falling on the surface tends to flow away rapidly, leaving very little for the recharge of groundwater. This makes most parts of India experience a lack of water even for domestic uses
30
Name the elements of water harvesting
1. Catchments
2. Conduits
3. Storage facility
4. Recharge Facility
31
What is the catchment of water harvesting?
The surface which receives rainfall directly
32
Which structures can act like catchments?
1. Paved area like a terrace
2. A courtyard of a building
3. An unpaved area like a lawn
4. An open ground
5. Temporary structures like sloping sheds
33
What are conduits?
Conduits are the pipelines or drains that carry rainwater from the catchment or rooftop to the harvesting system
34
Name the materials conduits are made of
1. Polyvinylchloride (PVC)
2. Asbestos
3. Galvanised Iron
35
Name various storage facilities
1. Reinforced Cement Concrete (RCC)
2. Masonry
3. Plastic water tanks
36
Name some recharge facilities
1. Dugwells
2. Borewells
3. Recharge trenches
4. Recharge pits
37
Alternative to storing, what can rainwater also be used to do?
To recharge groundwater aquifers
38
What is the function of recharge structures?
Ensuring that rainwater percolates in the ground instead of draining away from the surface
39
What is the mechanism of borewells and dugwells?
They are used to raise the underground water table by collecting rainwater on the rooftop of the building which is then diverted by drainpipes to a filtration tank. From there, it flows into the dugwell or borewell
40
What is the mechanism of a recharge pit?
It is excavated into the ground, lined with a brick or stone wall with openings at regular intervals
41
What is the mechanism of a percolation pit?
It is a bored hole of up to 30 cm diameter drilled in the ground to a depth of 3 to 10 m
42
What is another word for percolation pit?
Soakaway
43
What is the mechanism of recharge trenches?
They are excavated on the ground and refilled with porous media like pebbles, boulders, or brickbats to harvest the surface runoff
44
What is the mechanism of a permeable surface?
It is used to retain a large proportion of the rainwater falling on it, yielding only 10-15 % as runoff
45
Give an example of a permeable surface
A patch of grass
46
How are pavements and footpaths recharge structures?
They are made of porous tiles
47
Where can the storage tank be installed?
Inside the basement of a building or outside a building
48
Where can prefabricated tanks be installed?
PVC tanks - above the ground
49
What system should each tank have in case excess water enters the tank?
An overflow system
50
What is the overflow system connected to?
The drainage system
51
Which runoff is generally used for storing?
Runoff from paved surfaces, because it is relatively free from bacterial contamination
52
What is rooftop water harvesting?
It is a process of water harvesting in which rainwater falling on a roof is diverted through drain pipes to a storage container
53
Name the provisions provided in the water harvesting set up to clean the water
1. To prevent leaves and debris from entering the system, mesh filters are provided at the mouth of the drainpipe
2. A first-flush device is provided in the conduit before it connects to the storage container
3. If the stored water is to be used for drinking purposes, a sand filter is provided
54
Why does water quality improve over time during storage in a tank?
Due to the impurities settling down in the tank if the water is not disturbed. Even pathogenic organisms gradually die out due to storage
55
What is irrigation?
Irrigation refers to the process of watering of agricultural plants through artificial means from wells, tanks, tube wells, canals, etc
56
Give the distribution of usage of water
92 - Agriculture
2 - Industries
6 - Drinking and domestic purposes
57
How much of the net sown area depends on rainfall to sustain crop production?
55 %
58
What does success in dry farming depend on?
1. Moisture conservation practices
| 2. Judicious use of available water for irrigation
59
Give examples of two old canals
1. Two big tanks in the Chingleput district of Tamil Nadu constructed in 8th and 9th centuries AD
2. Grand Anicut built across the Cauvery river during the second century AD
60
Why was an increase in irrigation potential regarded as one of the prerequisites for the agricultural development of the country?
1. Uncertainty of Rainfall
2. Uneven distribution of Rainfall
3. Crop Requirements
4. Nature of the Soil
5. To Utilize River Water Effectively
6. To Maximise Production
61
What does rainfall irregularity lead to?
Water scarcity and withering of crops
62
Give the distribution of rainfall all over the country
1. Most parts of the country receive 80 per cent of the annual rainfall from June to September from the South-west monsoon
2. The Western Ghats and north-eastern India receive more than 250 cm annual rainfall, whereas the northern plains and the Eastern Peninsula receive between 100 and 200 cm of rainfall
3. The Kutch region of Gujarat, parts of Punjab and Haryana and the western half of Rajsthan lie in the arid zones
63
When do most crops not require water?
When they are maturing
64
Which crops require more water during the time the ear heads are formed?
Grain crops
65
Name the three cropping seasons of India
kharif, rabi, and zaid
66
Which crops occupy the largest area in the country?
Kharif - monsoon rains
67
What are kharif crops grown as, where irrigation facilities are not developed?
As rainfed crops
68
How are rabi crops grown?
They are grown on the soil moisture which is left after the harvest of kharif crops, or over the area where an assured supply of irrigation is available
69
How are zaid crops grown?
They are exclusively irrigated crops
70
Why do commercial crops like sugarcane need a higher quantity of water?
They require frequent watering which could only be managed through an efficient irrigation system
71
Which soils require less irrigation?
Clayey soils - They have a higher water holding capacity
72
Which soils require drip irrigation?
Sandy loams - They have less moisture-retentive capacity and need frequent watering
73
What does the level of land have to do with the amount of water required?
The level and lowland areas require less water than the sloping and highland areas
74
Which rivers remain largely dry during the eight months of the year?
The rivers of central and Southern India
75
In which season do the rivers of India carry insignificant flows?
Rabi season
76
How is production maximized through irrigation?
According to agricultural scientists, the production of irrigated crops is more than the unirrigated crops in the same area
77
Name the conventional means of irrigation
Wells, tanks, inundation canals
78
Name the modern means of irrigation
Tubewells, perennial canals, drip irrigation
