Straits Times
August 14, 2008

Overexploitation of underground supplies.

The Chinese government has made a huge effort to improve air quality
and beautify Beijing for the Olympics. But it cannot apply a short-term
fix to another problem that visitors to the Games will not see – the
steady depletion of underground water supplies in northern China, where
the capital is located.

A study published in June by Probe International, a Canadian
environmental research group, found that over two-thirds of Beijing’s
water is being pumped from beneath the ground to compensate for
dwindling surface water from reservoirs and rivers that once supplied
the city.

It warned that the underground saturation level, known as the water
table, is dropping because water is being pumped out faster than it can
be replenished. Plans for long-distance water diversion will aggravate
the impending crisis unless water is used much more efficiently.

Two years ago, the Bureau of Hydrology and Water Resources in Hebei
province, a major source of water for both Beijing and Tianjin, issued
a similarly stark warning.

It said that only severe overexploitation of underground water was
making up for the shortfall between water from rain and rivers, and
rapidly rising demand from urban residents, industries and agriculture.

Water shortage is not just a local issue affecting Beijing and its surrounding areas.

Mr Tushaar Shah is an Indian hydrologist with the International
Water Management Institute, part of a worldwide network of farm
research centres funded by the World Bank.

He estimates that India, China and Pakistan together pump 400 cu km
of water out of the ground each year, about twice as much as is
recharged by rain. These three countries, with a combined population of
nearly 2.6 billion, account for more than half the world’s use of
underground water for agriculture.

However, they are not alone.

The drilling of millions of deep wells and the extensive use of farm
pumps to bring water to the surface in the past 15 years in many parts
of Asia have helped raise food production – but at a long-term cost of
diminished underground water supplies.

Similar overexploitation of aquifers has taken place in the Middle East, South America, the United States and Australia.

Until a couple of years ago, the world was growing twice as much
food as it did a generation earlier. However, it was using three times
as much water to grow this food. Two-thirds of all the water irrigates
crops. For example, it takes about 1,000 litres of water to grow 1kg of
wheat and between 2,000 and 5,000 litres of water to produce 1kg of
rice.

By some calculations, as much as 10 per cent of the world’s food is
being grown using underground water that is not being replaced by rain.
As global warming intensifies, the implications for water security and
food production are alarming.

China is the world’s biggest grain producer. More than half of its
wheat and a third of its corn are grown on the northern plain. However,
the water table under the plain is falling fast.

Overpumping has largely depleted shallow aquifers, prompting well
drillers to tap deep aquifers which scientists say are so far below the
surface that they are not replenished by rainwater seepage.

Several years ago, the Geological Environmental Monitoring Unit in
Beijing reported that under Hebei province, the average level of deep
aquifers was dropping by nearly 3m a year.

When farmers in this semi-arid region are unable to continue drawing
water from underground aquifers to irrigate their crops, production
will decline.

Officials have said water shortages will soon make China dependent
on grain imports. The World Bank has warned that China faces
‘catastrophic consequences for future generations’ unless water use and
supply are brought back into balance.

In India, the situation is worse because farming is even more
critical to human survival and economic growth than in China. Nearly 70
per cent of its people rely on agriculture, which accounts for about a
quarter of the country’s gross domestic product. Underground water,
which now supplies 80 per cent of farm water, has become vital for
sustaining crops.

As the water table in many parts of India falls, water shortages
will become more widespread and the cost of pumping the remaining
underground water to the surface will rise.

In a country where poverty is extensive, one-third of the land is
semi-arid and rainfall is seasonal and erratic, this will make it
difficult for many farmers to grow enough food unless they find ways to
conserve rainwater and use it sparingly.

The writer is an energy and security specialist at the Institute of Southeast Asian Studies, Singapore.