Thursday, July 10, 2014

India plans the grandest of canal networks

Under the river-linking project, surplus water from the Brahmaputra River would be diverted to parched regions in northern India.
In one of the most ambitious engineering projects ever conceived, the Indian government is preparing to forge ahead on a plan to build a 15,000-kilometer-long network of canals and tunnels that would move 174 billion cubic meters of water each year—almost a third of the amount the United States withdraws from aquifers each year—from areas with surplus water to parched regions of India.
The prime rationale for the $168 billion National River Linking Project (NRLP) is simple: To feed its growing population, the Indian government has determined that it must drastically expand its arable land. Now, about 100 million hectares in India are irrigated; NRLP, if fully implemented, would increase that amount to about 135 million hectares, while also curtailing flood damage during the summer monsoon season and adding another 34 gigawatts of hydropower capacity. The current plan, honed by India's National Water Development Agency, envisions 16 links between Himalayan-fed rivers and rivers in drought-afflicted western India, and another 14 links in the southern half of the peninsula (see map). Newly elected Indian Prime Minister Narendra Modi has hailed the “river interlinking project” as a national “dream.”
Thanks to Modi's patronage, that dream is moving closer to reality. “All possibilities will be explored for early implementation of the river interlinking project,” Uma Bharti, India's new water minister, told Science at a meeting here on 7 July on cleaning up the Ganges River. But NRLP, which could take upward of a quarter-century to complete, faces political hurdles and scientific dissent. Critics contend that the water transfer would spread invasive species and waterborne diseases and interfere with fish migration. Water-rich states may also balk at sharing. “There will undoubtedly be winners and losers,” says Donald Alford, a hydrologist who has studied the Himalayas with the firm Mountain Hydrologic Systems in Billings, Montana. “Who, and where they are, will help to define feasibility.”
The Indian government first proposed a “national water grid” in 1972, but the idea, featuring a 2640-kilometer-long canal between the Ganges and Cauvery rivers, was shelved due to cost. Over the years, as the project's aspirations grew, political support “waxed and waned,” says Upali Amarasinghe, a statistician with the International Water Management Institute in Hyderabad. Several links were built, including one between the Narmada and Sabarmati rivers in Gujarat state, which Modi governed before becoming prime minister.
India's previous government, led by Manmohan Singh, was never enamored with NRLP and did not push for broad implementation. “River interlinking is against the forces of nature,” says chemist T. Ramasami, the former secretary of the Department of Science and Technology who chaired a Supreme Court–mandated expert committee on water issues. “Intense scientific scrutiny,” he says, is necessary “before such a big project is undertaken.”
NRLP critics say that Singh was right to keep the project on ice. “The equation that flooding means surplus water and drought means deficit is misleading and wrong,” argues Himanshu Thakkar, an engineer with the South Asia Network on Dams, Rivers and People, an advocacy group based here. He points out that areas with heavy monsoon rainfalls can face water scarcity during the dry season. Moreover, NRLP's viability depends on states sharing water resources—an unreasonable assumption, Thakkar says, because “all of them are equally facing increasing scarcity of water. From this point of view alone, the links are unviable.”
That's not how Bharti sees it. She contends that Singh's government “slept” on the project, even after the Supreme Court in February 2012 held that NRLP “is a matter of national benefit.” In a sign that the new government will push ahead, last month it granted permission to Gujarat to raise the height of the Sardar Sarovar Dam by 17 meters, taking it to 138 meters. Completed in 2006, the hydropower project transfers water across basins to irrigate 1.8 million hectares; raising the height would irrigate another 68,000 hectares.
Modi's government is still thrashing out just how fast it will move on NRLP. Its near-term ambitions will become apparent when it releases its first budget, for 2014 to 2015, later this month. Whatever shape NRLP takes, Bharti assures Science that “no environmental laws will be broken.”