Productivity of Water and Environmental Security
07 Oct, 2001 · 596
Col PK Gautam advocates increased efficiency in utilization and production of water to guard against the threat of water shortage in India
The annual precipitation over
India by rain and snow is 4,000 cubic kilometers (cu.km). Out of this, the annual run off is 1869 cu.km. Out of this run off, it is estimated that 690 cu.km of surface and 432 cu.km of ground water or a total of 1122 cu.km is utilizable every year. This amount on the supply side is fixed; out of which about 750 cu.km is used. For instance, the all-India storage capacity of large dams at present is 174 cu.km. This storage would increase when more storage dams are commissioned. A greater area will also be brought under irrigation, and more ground water resources will be tapped. It is appreciated that between 2025 and 2050, demand will catch up with the supply.
India being an agricultural country, the percentage of water used for agriculture is 84%, and for industries/domestic/other uses it is 16%. This share of agriculture is projected to reduce to 73% by 2025 due to demand from the growing industrial/domestic sectors.
India will be 1469 cu.m.
With better technology as seen in
Japan and US, water productivity improves. In 1965, 13 million gallons of water was required to produce 1 million dollars worth of commercial output in
Japan . Productivity has quadrupled for the same output, but the water required dropped to 3.5 million gallons. In US, water withdrawals have fallen by more than 20 per cent from its peak withdrawals in 1980. To produce one ton of steel before World War II there was a need for 60-100 tons of water. The current technology for the same amount of steel uses 6 tons of water, whereas only one and a half tons of water is needed to produce one ton of aluminum. As we progress, water productivity would become an important input.
At the global level, the ratio of water for the three main uses – agriculture, industry and domestic use – is approximately 7:2:1.
This implies two things. First, the per capita availability will drop due to population growth and more demand for water with affluence/growth. Secondly, the three main uses of water between agriculture, industry and domestic use would be in conflict due to water supply being finite.
According to international norms, below 1700 cubic meter (cu.m) of water per capita per year implies occasional and local stress. Below 1,000 cu.m implies water stress, and below 500 cu.m implies serious constraint and threat to life. With a medium population growth projection, by 2025 per capita availability in
One of the best solutions, besides recycling, to tide over water stress is to treat it as a commodity like electricity to avoid waste. But due to political reasons it may not be possible to charge for water across the entire spectrum. Another method is to give due importance to the productivity of water.
Table 1 provides a rough guide to the scales of consumption of water for agriculture and industry applicable to South Asian conditions of present agricultural/ industrial practices and machinery.
TABLE 1: WATER USE FIGURES FOR PRODUCTION
| ITEM
|
WATER REQUIRED
IN LITRES
|
| One litre of petroleum
|
10
|
| One kilogram of paper
|
100
|
| One ton of woolen clothes
|
600
|
| One ton of dry cement
|
4,500
|
| One ton of steel
|
20,000
|
| One kilogram of wheat
|
900
|
| One kilogram of rice
|
1,900
|
| One kilogram of grain fed beef
|
100,000
|
In agriculture, it is seen that 50 percent of water for irrigation never yields any food. Water from irrigation channels often gets wasted. Overuse also causes waterlogging and salinity. The answer lies in improving efficiency by drip irrigation and improved farming practices. Also, water intensive crops like paddy and sugarcane should not be grown in agro-climatic zones unsuitable for them, even if plenty of water is available. Traditional check dams and ponds also need to be revived.
In the domestic sector, where the demand is growing due to rapid urbanization, rooftop water harvesting is one easy option. Another is to reduce leakages in pipes and use less water-intensive gadgets as in flush systems for toilets. Maximum capacity should be prescribed during building design and fitments. Extra large water guzzling tanks should be banned by law. Apart from conserving water and improving the efficiency of its utilization, attention should be paid to recycling water from waste disposal.
There is no substitute for water. This makes water shortage an emerging issue in environmental security. The 20th Century had ushered in atoms for peace. The 21st should usher in water for peace by improving its productivity.
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