Imagine that your close friend has not been attending school
for two weeks because of Malaria. Write a letter to himher
and ask how he / she is now. In your letter, comfort tim
her and wish him quick recovery. Assure him/her that what
you have covered during his / her absence is not so much
and difficult, and that you and the teachers will try your best
to help him/her catch up.
Answers
Answer:
We know that water is necessary, both for sustainable human development and for the healthy functioning of the planet’s ecosystem. Availability of freshwater globally however, is limited. Out of the 2.7 per cent of a total amount of 1 400 million km3 of freshwater, the major portion occurs in the form of permanent snow cover or deep aquifers and only a small fraction is available for use.
Although India has to support 16 per cent of the world’s population and 15 per cent of livestock, we have only 2.4 per cent of the land and 4 per cent of the water resources of the world. Out of about 4 000 km3 of precipitation in a year, as much as 3 000 km3 comes as rainfall in a short monsoon period of three to four months from June to September. The distribution of the water thus available is not uniform and is highly uneven in both space and time. The average annual water resource potential of the country is estimated to be 1 869 km3. Due to hydrological, topographical and geological limitations, however, only 690 km3 of surface water can be utilized by conventional storage and diversion structures. The annual recharge of groundwater is 433 km3.
Two major problems faced by the country are drought and floods, which are discussed in the succeeding paragraphs:
Floods and drought
Today, droughts and floods are a common feature and their co-existence poses a potent threat, which cannot be eradicated but has to be managed. Transfer of the surplus monsoon water to areas of water deficit is a potential possibility. This would also help create additional irrigational potential, the generation of hydropower, as well as overcoming regional imbalances.
The recurrence of drought and famines during the second half of the 19th century necessitated the development of irrigation to give protection against the failure of crops and to reduce large-scale expenditure on famine relief.
Floods in India
Floods are recurrent phenomena in India. Due to different climatic and rainfall patterns in different regions, it has been the experience that, while some parts are suffering devastating floods, another part is suffering drought at the same time. With the increase in population and development activity, there has been a tendency to occupy the floodplains, which has resulted in damage of a more serious nature over the years. Often, because of the varying rainfall distribution, areas which are not traditionally prone to floods also experience severe inundation. Thus, floods are the single most frequent disaster faced by the country.
Flooding is caused by the inadequate capacity within the banks of the rivers to contain the high flows brought down from the upper catchments due to heavy rainfall. Flooding is accentuated by erosion and silting of the river beds, resulting in a reduction of the carrying capacity of river channels; earthquakes and landslides leading to changes in river courses and obstructions to flow; synchronization of floods in the main and tributary rivers; retardation due to tidal effects; encroachment of floodplains; and haphazard and unplanned growth of urban areas. Some parts of the country, mainly coastal areas of Andhra Pradesh, Orissa, Tamil Nadu and West Bengal, experience cyclones, which are often accompanied by heavy rainfall leading to flooding.
Area prone to flood
In 1980, Rashtriya Barh Ayog (National Commission on Floods) assessed the total area liable to flooding in the country as 40 million hectares (ha), which constitutes one-eighth of the country’s total geographical area. The Working Group on Flood Control Programme set up by the Planning Commission for the Tenth Five Year Plan put this figure at 45.64 million ha. About 80 per cent of this area, i.e. 32 million ha, could be provided with a reasonable degree of protection.
Damage from floods
More significant than the loss of life and damage to property is the sense of insecurity and fear in the minds of people living in the floodplains. The after-effects of flood, such as the suffering of survivors, spread of disease, non-availability of essential commodities and medicines and loss of dwellings, make floods the most feared of the natural disasters faced by humankind.