This is Eileen Wray-McCann for Circle of Blue. And this is What’s Up with Water, your “need-to-know news” of the world’s water, made possible by support from people like you. 
In Southeast Asia, China has notified nations downstream of the Mekong that it is reducing the river’s flow for 20 days. The news comes from the multinational organization overseeing the lower Mekong River. Reuters reports that the statements came a day after a new U.S.-backed monitoring system found that China had started restricting water on December 31 but had failed to notify countries along the Mekong. Chinese officials say they’re holding the water back in order to repair electrical lines around a dam. The river is expected to drop by more than a meter downstream, and the change in water level could affect fishing and shipping. Last October, China reached an agreement to share water data with basin partners Thailand, Laos, Cambodia and Vietnam, where 60 million people depend on the Mekong River for fishing and farming.
New research warns that without action, land that is gradually sinking could affect nearly 20 percent of the world’s population in a couple of decades.  The land-sinking phenomenon is known as subsidence, and it continues to threaten many of the world’s coastal cities with flooding. The Guardian reports that subsidence can be caused by the extraction of groundwater, which is worsened by the lack of pumping regulations and rapidly increasing populations. An international team of scientists found subsidence to be a global issue linked to global warming and to unsustainable farming practices. Solutions range from satellite and radar monitoring to local policies that regulate groundwater pumping.
In Bolivia, the Tuni glacier, with its water, is vanishing much faster than forecast. Scientists from one of the country’s top universities say that the glacier, which had been predicted to last through 2025, is now in imminent danger of disappearing. Reuters reports that climate change has reduced the once sprawling glacier to about one square kilometer. The loss of the Tuni glacier will likely worsen water shortages in Bolivia’s capital La Paz, which sits just 37 miles from the glacier. The mountain ice has historically fed rivers used for crop irrigation. And according to the scientists, the glacier also supplied at least 20 percent of the city’s water.
This week Circle of Blue looks at a study showing just how much India’s farmers are pivotal to the country’s water future.
India’s leaders have ambitious goals for the nation’s economy.  The “Make in India” campaign intends to lift the manufacturing sector to a place of prominence.
To do that, they will have to address what Dr. Vaibhav Chaturvedi says is one of the country’s greatest policy challenges: how to reduce water use by farmers.
Farming is where the water is in India, accounting for nearly 80 percent of the country’s water withdrawals. Farming is also where the labor is, employing more than two in five workers. But India’s farmers are among the world’s least efficient water users. Conflicts over water supplies are a frequent in a country beset by stifling heat, rampant groundwater depletion, diminishing reservoirs, and nearly one and a half billion people.
Chaturvedi is a fellow at the Council on Energy, Environment, and Water, one of the country’s most respected environmental policy think tanks. He told Circle of Blue that the conflicts of recent years promise to intensify.  In his eyes, water waste in agriculture is a failure of policy and practice. But it also presents an opportunity. He and his colleagues describe the potential gains in a report on more-efficient water use.
It’s a matter of tradeoffs, say the authors of the study. If India’s least-efficient farmers could match their thriftier peers — getting the same amount of crop but using far less water to do it — there would be a hydrological dividend. That extra water could restore degraded ecosystems, or it could be transferred to the manufacturing sector, where water yields products with a higher market value than those from farming.
With this type of efficiency, there would be no net change in agricultural production. India would still produce the same amount of food and fiber. But the water saved could boost manufacturing output – and limit environmental damage, because there would be less need to rely on overtapped aquifers and rivers, or to construct dams.
The gains are not merely theoretical. The study used real-world examples to show how much water could be saved without reducing farm output. The report did this by measuring the water-use performance of the most water-efficient farmers in three states — Andhra Pradesh, Maharashtra, and Uttar Pradesh  — and comparing them with those less water-wise. Comparisons included eight key crops, such as legumes, sugarcane, cotton, and rice.
The potential for water savings varies by crop and by state. But overall, this could make a major difference. In a low-savings scenario, where all farmers are brought up to average performance, water withdrawals could be reduced by 20 percent. In a high-savings scenario, in which all farmers achieve top-tier efficiency, withdrawals are cut by 47 percent. That water could be redirected to industry –  and to homes. India intends to expand piped water service to all rural households by 2024.
Chaturvedi said the potential for sizable water savings is not surprising. The real value of the study, he says,  is quantifying the range of what is possible by using real-world data.
The question arises: Why are India’s farmers less efficient than others around the globe?  In comparison, Israel and parts of the United States use finely-tuned irrigation for their specialty crops. Soil probes indicate when moisture is low and water is needed. Irrigation schedules are planned around rain events. Sprinklers and drip systems apply only what the crop requires, and no more.
Chaturvedi said that India’s lack of water efficiency is largely due to outdated policies and practices. Farms that irrigate fields by flooding them, for instance, lose a lot of water to evaporation. Electricity that is subsidized by the government encourages the over-pumping of groundwater. And minimum market prices set by the government result in water-hungry rice being grown in arid Punjab, where the crop demands more than twice as much water compared to rice grown in rainier West Bengal.
Murtaza Hasan is a principal scientist at the Indian Agricultural Research Institute. He told Circle of Blue that improving the water productivity of Indian agriculture is “urgently required.” He said India should shift away from “water-guzzling” crops such as sugarcane and rice as soon as possible. But Hasan was more cautious about immediately transferring the water savings to industrial use. He said that should only happen after the appropriate policies are in place.
Chaturvedi said the next step for his group is to look more deeply at those policies, and see which economic, administrative and political levers are most suitable in any given state. Pilot programs in small watersheds could test the strategies before they were expanded. If all goes well, they could point the way to wiser water use across India — and lessen the risk of conflict.
And that’s What’s Up With Water from Circle of Blue, which relies on your support for independent water news and analysis. Please visit and make a difference through your tax-deductible donation.