Rice :: water relationship / INDIA

According to the Comprehensive Assessment, there are currently about 300 million hectares of irrigated land worldwide—double the area in 1960. About 80 million hectares (27%) of this irrigated land is used for rice production. Because rice receives more water than other crops, it uses some 39% of the world’s irrigation water.

One is based on maps of irrigation schemes (Siebert et al), which may include areas that could be, but may in fact not be, irrigated; the other is based on satellite data (Thenkabail etal). The relative strengths and weaknesses of these two sources are open to debate, but they have at least one limitation in common: they show only the presence or absence of irrigation, not how much water is currently available or will be in the future. This is important because the future of irrigation is uncertain in many areas.


Climatic Change its effect on rice cultivation in India


In India 51 percent area under rice cultivation is irrigated, and the rest 49 percent is rain-fed. 51% area area depends on the rivers but the risk of the melting glacial region in the future will have drastic effect the cultivation, Indian peninsula has a history of deep drought situation with an approximately a 31% probability chance. The decrease in ground water table is one major concern at present for agricultural in India. (will cover in the other section of the research)

The Himalayan range contains high altitude glaciers that supply water to many rivers in Asia. These rivers provide water to more than half of the world’s population. Many people in Asia are dependent on glacial melt water during dry season. 

Accelerated glacial melt questions the very perennial nature of many of the Himalayan flowing rivers. This is likely to have huge implications on those dependent on the resource affecting water availability for agricultural purposes. In Nepal and Bhutan, melting glaciers are filling glacial lakes beyond their capacities contributing to Galcial Lake Outburst Floods (GLOFs) (UNEP 2007).


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A recent study for the World Bank has shown that the volume of water resulting from glacial melt in Nepal makes up less than 5% of the flows of rivers leaving the country and contributing to the Ganges downstream.

"That is, about 95% or more of the river flow is the result of rain and melting seasonal snow," said report co-author Richard Armstrong, a glaciologist from the University of Colorado at Boulder, US.

If that is true, rivers downstream of the eastern Himalayas will hardly be affected, even if the glaciers recede or disappear.

However, would the other contributing factors to the rivers' flow, such as precipitation and snowfall, remain the same in the changing climate?

No, say scientists, but whether that will lead to rise or fall of rivers' levels - and by how much and when - are the questions still waiting to be answered.

Some scientists say increasing temperature has meant that glaciers don't get enough snowfall during winter and therefore river flow during summer is dwindling.

"We have seen the decline in the flow of the Indus, Chenab and Jhelum rivers," says Professor Mohammad Sultan Bhat of Kashmir University, who has conducted field studies with India's flood and irrigation department.

"We have recorded a decrease of 40% in the flow of Jhelum's tributary river… that is fed by the receding Kolahi glacier."

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India accounts for the largest share (59%) of the total drought-prone rice area in Asia. Most of these drought-prone areas are rain fed. In India, major droughts in 1918, 1957-58, and 1965 resulted in famines during the 20th century (FAO 2001). The 1987 drought affected almost 60% of the total cropped area and 285 million people across India (Sinha 1999).

Minor famines of 1860,1866,1869 and 1874 and extremely severe famine of 1877 and 1878, 1889 famine then in1896,1897, 1900,1901, 1902 minor famine1906,1907,1908,1909, drought 1915 then 1919 famine,

India drought 1950, 1951, 1952, 1958, 1963, 1964, 1965, 1966, 1967,1968 – 1971, 1972, 1973, 1974, 1979, 1982, 1983, 1985, 1986, 1987, 1988 - 1993, 1996, 2000, 2001, 2002, In India, drought is a perennial phenomenon, recurring every few years. The country witnessed 40 droughts of varying intensity during 1876-2002. This translates into approximately a 31% probability of drought.