Punjab is the granary of India thanks to marvels of Victorian engineering such as the Roper Headworks.

The 127-year-old system of small stone dams and hand-operated iron gates diverts the Sutlej river into the 3,200-kilometre Sirhind canal network which irrigates 1.3m hectares of land.

However, while the colonial-era system and five other large canal networks across Punjab are crucial for farmers, their water-carrying capacity has been gradually eroded as silt, crumbling brick linings and vegetation have increasingly clogged the channels.

Routine maintenance has been postponed for years as irrigation officials have struggled to find revenues because water is given free to farmers. “We don’t have even a single penny for grease to lubricate the chains,” says one engineer.

The degradation of the irrigation system reflects a wider crisis in India’s water supply. The International Water Management Institute and the Food and Agriculture Organisation have warned Asian countries to reform water policies urgently and step up irrigation investment if they are to meet future food needs.

Across north India, water demand has surged in recent decades with increased cultivation of rice, a particularly thirsty crop. Disappointing monsoon rains this year have exacerbated the water shortfall.

As flows through the Sirhind canal run at 30 per cent less than full capacity, Baltej Singh, a local farmer, has decided he can no longer afford to rely on the system for his 2.8 hectares, even though they lie beside a small brick water channel at the tail end of the irrigation network in Muktsar, near the Pakistan border. Mr Singh has hired a contractor to dig a tube well for less than Rs100,000 ($2,000, €1,400, £1,200). It will supply water on demand, with the help of free power provided to farmers by the Punjab government. “There is very little water coming from this canal,” he says. “What else can I do?”

Many local farmers are doing the same. Jagdev Singh, the tube-well digger, says business is booming. His 10 drilling rigs have been busy every day recently. “There is only life with water,” he says.

But while tube wells have helped farmers to overcome the limits of the surface irrigation system, they are severely straining India’s ground water resources – now in danger of depletion as a result of severe overuse.

Last month, scientists writing in Nature magazine estimated during the past six years – a period of relatively normal rainfall – north India lost ground water equivalent to twice the amount in the country’s biggest reservoir. Suresh Kumar, Punjab’s leading irrigation official, estimates ground water is currently being used unsustainably at 145 per cent of the natural recharge rate.

So far, Indian politicians have shown little will to charge for power and water in order to encourage more judicious use and to generate revenue for fresh irrigation investment. The former chief minister of Andhra Pradesh state increased power prices several years ago, only to be voted out by angry farmers and his measures reversed.

“As politics gets more competitive, no party wants to disturb the apple cart,” says Manpreet Singh Badal, Punjab’s finance minister. “That’s the politics of water.”

Since last year, Punjab has prohibited sowing rice before June 10 to prevent farmers from growing two annual crops and to ease pressure on water supplies. New Delhi also offers a 50 per cent subsidy to farmers to install drip and sprinkler irrigation systems, which use much less water than traditional flood irrigation.

Mr Badal argues only phasing out power and water subsidies will bring sufficient change to water use and crop patterns to avert an ecological disaster, although his efforts to persuade the state government have been unsuccessful.

“Since water is free, there is no incentive for farmers to try newer technologies,” he says. “That entire sensitivity that this is precious – and there is a limited amount – is missing. But this direction can only come from the government – not from individual farmers.”

Mr Kumar, the irrigation secretary, says authorities will eventually be forced into such tough decisions. “We can’t sustain the system without charging something,” he says. “It’s only a matter of time.”

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