Autumn rainfalls came too late to save the stunted stalks of Shu Xinguo’s corn crop, withered by a dry July developing season.

“We rely on the weather for our living, ” said Shu, weary and vacated, his tanned hands hoisting sheaves of his remaining harvest — green and yellow tobacco leaves — onto a three-wheeled tractor.” There’s no water for irrigation, and the well in the village has no sea either .”

Sixty kilometers away, China’s largest aqueduct hauls as much as 18.3 million cubic meters of fresh water a period through Shu’s province to quench the growing thirst of Beijing in the north. None of it comes to Shu’s village or any of thousands of farms in the region.

It’s China’s age-old dilemma: a tug of war between the farms that help feed the commonwealth, and the surging demands of industry and city-dwellers in the parched northern plains.

With an excess of rain in the south and not enough in the northern part, China’s solution is as simple as it was expensive: Build three massive aqueducts to divert the sea for an estimated costs of more than 500 million yuan ($ 76 billion ).

The result is the world’s more ambitious water transfer program, the South-to-North Water Diversion project. Its middle channel — from the Danjiangkou reservoir to Beijing and Tianjin — was finished in 2014. Proposed in the time of Chairman Mao Zedong, it is a stunning engineering achievement. Some 11 billion cubic meters of water has spanned the 1,432 -km-long waterway, rendering factories, businesses and 53 million residents.

It isn’t enough.

” As the country’s economy develops, industries are using more water ,” said Huanguang Qiu, a professor with the School of Agricultural Economics and Rural Development at Renmin University.” And the rivalry will become even more fierce.”

Beijing, which gets about 70 percent of its sea from the South-North diversion project, is expected to add another two million people before the governmental forces caps the city’s population at 23 million.

President Xi Jinping announced plans in April to build a new metropoli, Xiongan, about 100 kilometers southwest of the capital. With an estimated 5.4 million people, it would also be fed by the aqueduct.

Even when the waterway reaches maximum capacity in 2019, China’s demand is growing so quickly that other solutions will be needed. Rivers and aquifers poisoned by years of poor control over fertilizer its utilization and mill effluent need to be cleaned up, trash reined in and wrongdoers punished.

The result is a revolution in accordance with the rules China applies, monitors and allots its most precious resource. Farms are changing harvests and embracing engineering to conserve irrigation, industries are being was necessary to clean up effluent, citizens are taking to social media to report delinquents and the government is adapting a long-held food security policy to rely more on the importation of water-hungry crops.

Part of the problem is that China doesn’t merely need to find enough sea to furnish its rising demand, it also must be free to replenish aquifers that have been depleted for years.

” Industries and metropolis had been outlining down underground water as deep as is practicable, which took away sea from farming ,” said Yu Hequn, director-general, Construction and Administration Bureau of the South-to-North Water Diversion Central Route Project.” Now we are returning water to agriculture and the ecosystem .”

By 2015, 230,000 square kilometers were being affected by over-extraction of groundwater, mostly in the north, leading to ground subsidence, sea water intrusion and other troubles, the Ministry of Environmental Protection said.

The depletion is worst in northern states like Hebei, which surrounds Beijing, and neighboring Henan. At least seven giant sinkholes have been reported in Hebei, where farmers have drilled ever-deeper boreholes. The government has promised to divert billions of cubic meters of water from the Yellow River to farms to ease the famine. Even so, Hebei could still face a water shortage of 1 billion cubic meters by 2030, Zhang Tielong, deputy head of the provincial water resources department, said when the South-North waterway opened in late 2014.

One way to stem the reduction in groundwater is taxes. Last month, the government expanded a sea resource tax trial to encompas nine boroughs and states, with jobs ramping up if quotums are outperformed. Regular sea tax rates were highest in Beijing and Tianjin, according to China’s finance ministry, and sea from underground will be taxed at twice the rate or more than for surface water.

Another option is to import food that requires a lot of moisture to develop — nearly half of China’s farmland has no irrigation system. That’s not straightforward, as China also has a long-standing food-security policy that aims to be largely self-sufficient in staple grains.

“We should make full use of international markets to increase supplies and should not fret too much over rising importations, ” said Fang Yan, a researcher with China Institute for Rural Studies at Tsinghua University. She said the government has asked some wheat farmers to change to water-saving crops.

Each ton of imported wheat saves China about 500 cubic meters of sea and 0.4 acres of farmland, Fang said. The country is already the world’s largest importer of soybeans, but could buy more, as well as meat and dairy products, she said.

But an increase in grain importations would set a further strain on world food markets. China’s soybean requirement has inspired farmers in Brazil to turn over some 13 million hectares of farmland and forest to growing the crop in the past 10 years, an area about the size of Germany.

In China, urbanization has reduced the amount of farmland in the water-rich south while provinces in the northern part, which get only 20 percentage of the country’s rain, grow more than half the nation’s grain thanks to increasing employ of irrigation, she said.

Scientists are breeding wheat seeds for the north that need 20 percent less sea, said He Zhonghu, a researcher with the Chinese Academy of Agricultural Sciences.

With urbanization sucking up most of the supplying from the sea transfer project, China is turning its focus to better apply of the water it has. Some of its biggest engineering companies are contributing the way.

Internet giant Tencent Holding Ltd. is working with local governments including Shenzhen to encourage the spread of so-called sponge cities — underground reserves and ponds on the tops of builds that catch and store rainwater.

The idea was raised in 2015 by the State Council, China’s cabinet, and was mentioned in Tencent Chairman Pony Ma Huateng’s National People’s Congress proposal in March. Tencent is using its three new skyscrapers in Beijing, Shenzhen and Wuhan as pilot projects .

Another solution is better irrigation. More sea be applicable to irrigation than any other purpose in China — about 55 percent of the total. Irrigated land renders 75 percent of China’s grain and over 90 percentage of cash crop such as cotton and vegetables.

Bigger farms are trying new techniques, like Xinjiang Tianye Group‘s system that can reduce sea utilization by as much as 50 percentage, according to Chen Lin, the company chairwoman. Its machines delve rows, lay tubes for drip-irrigation, encompass the soil with plastic film to reduce evaporation and punch pits to flower the seeds, all in one sweep.

While the technology helps farmers develop everything from cotton to rice, it comes with a hitch: the plastic sheets don’t break down in the soil, to move to widespread pollution.

Not far from Shu’s farm in Henan province, Muyuan Foodstuffs Corp . and the local government are constructing a pilot farm to demonstrate a drip technology from Israel.

” Normally, we flood fields with water during irrigation ,” said Pang Bo, a manager with Muyuan, as he walked through a white plastic greenhouse that will be used to grow tomatoes.” The trickle technology can save sea by more than 60 percentage .” The facilities cost about 3.3 million yuan for one 0.33 -hectare greenhouse with a ventilation and cooling system.

Still, in many cases there’s little incentive for farmers to save sea. Agriculture employs 62 percentage of China’s water, but crops have a relatively low marginal value. So the government bannings sales of agricultural sea to industry, which pays 10 hours the cost, to ensure food supply.

With that barrier, Chen asks,” What are the incentives for saving water ?”

To address this, the State Council in January 2016 began to reform the country’s agricultural water tariffs to encourage more efficient use. A national China Water Right Exchange was set up in June 2016 and a water-rights trade system will follow. The government has determined a cap for irrigation of 372 billion cubic meters by 2020.

It also has plans for a third canal, supplementing the Danjiangkou-to-Beijing route and the first channel, which largely uses the old imperial Grand Canal system to move sea along the eastern seaboard. The western one would divert sea from three tributaries of the Yangtze River to help replenish the Yellow River. It is the most controversial and challenging of the three, channeling water in all the regions of the vast Qinghai-Tibet plateau that could diminish supplyings for rivers that flow through neighboring countries to the south.

Even as China contemplates such a technological and political challenge, another specter is looming. Recent measurings suggest China’s water distribution may be made even worse by climate change.

The flow of the Han River, which fills the three gorges reservoir in the early stages of the giant aqueduct, shrank by 7.18 billion cubic meters in the decade to 2010, according to Liu Changming, a water scientist at the Chinese Academy of Sciences.

In the nation’s Third National Assessment Report on Climate Change in 2015, the governmental forces said rising temperatures and changing rainfall patterns were putting greater stress on agriculture, especially staple crops like rice, wheat and corn.

That’s one more difficulty for Cheng Mingzhen, 66, who develops corn on a small farm in Henan province. She said she can practically reek the water from the Beijing aqueduct, which passes through her village of Dazhuang.

“There is no outlet from the canal ,” she said, looking toward the high wire fencing that retains intruders out.” We is also difficult to get close to it, let alone get sea for the crops.”