Narendra Modi is not noted for building bridges. The Indian prime minister, already viewed warily by non-Hindus, reportedly plans to speak Hindi when meeting international leaders, despite being fluent in English. He has also upset Delhi bureaucrats by ordering them to clean their offices and drop golfing lunch breaks.

Modi would, however, like to be remembered for building canals. He dreams of reviving an ambitious, decades-old national plan to connect India’s rivers, including the sacred Ganges and the snow-fed Indus, with 15,000km of canals and reservoirs to enrich farming prospects and provide an escape route for flood water. It is a pipe dream almost without precedent: a $168 billion (Dh617 billion) project lasting at least 25 years that will leave virtually no state untouched.

Supporters claim the grand South Asian water grid, more prosaically known as the National River Linking Project, is the aquatic answer to this fast-growing economy’s multiple needs. According to a report in the journal, Science, the latticework of conduits, mainly channelling water from the north and east of the country into the parched south and west, will expand the available agricultural land by a third; add 34 gigawatts to the hydroelectric output (roughly equivalent to the electricity generated by 20 nuclear power stations); and end the misery of flood damage by diverting water to arid areas. It could also create a carbon-friendly transport network.

Critics, however, contend that it is unbridled hydrological hubris on a par with China’s superdams, and that drastic re-engineering of the country’s natural water courses could exact a heavy toll on the environment, interfering with fish migration and spreading waterborne diseases. As well as environmental objections, there are worries about how it will work in a divided country: India is carved into 29 states, plus other territories, that boast their own governments, languages and ethnic histories. And Bangladesh and Pakistan may not feel that upbeat about being downstream neighbours. A Chatham House report last month described international discussions about dwindling water supplies in south Asia as “vociferous, antagonistic and increasingly associated with national security”. Where there is no shared love, there is unlikely to be shared water. As the Financial Times spells out in its series, A World Without Water, scarcity is a pressing and relatively ignored global issue. With India supporting 17 per cent of the world’s population with only 4 per cent of the water, Modi has at least recognised that the present water management plan is in danger of stagnating. And, perhaps pricked by a World Economic Forum survey ranking the country’s infrastructure below Guatemala’s, his maiden budget this month included pledges to build railways, airports and roads. Championing a national water grid, an idea first proposed in the 1970s, adds buoyancy to his claim to be a progressive leader.

Haphazard building

The great challenge for this vast country is that, when it comes to dispensing water, nature is neither measured nor equitable. According to the World Meteorological Organisation, three-quarters of India’s annual precipitation (rainfall, snow or any other form of water falling from the sky) is crammed into just a third of the year, during monsoon season. As a result the country, measuring 3,219 km (2,000 miles) north to south, is beset by both flood and drought, sometimes at the same time, with deluges made worse by haphazard building on flood plains.

A master plan for the national redistribution of water has long been touted as a long-term solution, both in terms of smoothing supply and mitigating the floods that cause so much personal anguish and economic damage. The seductive logic of redistribution, though, is regarded by many as unscientific. “The equation that flooding means surplus water and drought means deficit is misleading and wrong,” Himanshu Thakkar from the campaigning group South Asia Network on Dams, Rivers and People, told Science. Monsoon-hit areas, he explained, can be drought-ridden at other times of the year and therefore need ways of conserving, not offloading, water.

Manmohan Singh, Modi’s predecessor, showed little enthusiasm for the scheme. It was deemed “against the forces of nature” by one advising committee, which called for intense scientific scrutiny. Of itself, nature should not be a barrier to progress, but a thorough scientific analysis is desperately needed. Ambition alone will not make the torrents flow in the correct direction nor dispel fears about ravaged ecosystems or displaced villagers. Any analysis must also take climate change into account: by the time the final waterway is opened, it is possible the Himalayan glaciers feeding some of the rivers will have retreated, rendering the original calculations less relevant. If Modi really plans to buy into this mega-project, he will either sail into history as a visionary or as the fool who floated his country up a certain creek.

— Financial Times

The writer was named best science commentator at the 2013 Comment Awards.