Written in huge red Chinese characters across the Sanmenxia dam, just outside the ancient city of Luoyang, is a phrase from Chinese mythology: "When the Yellow River is at peace, China is at peace."
It's a phrase that still resonates today, but in a slightly different way.
In ancient times, the problem was flooding that killed more than a million people over the centuries — causing numerous peasant rebellions and challenging every emperor who sat upon the Dragon Throne.
Now, the problem is reversed. In the past, man needed to be protected from the waters of the Yellow River; now, the river needs to be protected from man. China's rapid economic development and the growing environmental emergency threaten the country's mother river.
All along the banks of the Yellow River, the contradictions of modern China come into sharp focus: the need to create jobs to keep the economy growing leads to more pollution, while the need to use water for developing industry and for the booming cities in turn drains the river.
Experts list a litany of apocalyptic statistics: Northern China is home to 43 percent of the population but only 14 percent of the country's water supply; 400 of China's 600 cities lack an adequate supply of water, and many are draining underground aquifers; 4 billion gallons of wastewater are dumped into the river every year, double the amount from two decades ago.
For three years in the 1990s, the Yellow River dried up hundreds of miles before it reached the sea. Overuse and pollution led some experts in China and abroad even to speak about the waterway becoming an inland river and never regaining the water it had lost.
But the importance of the Yellow River — symbolically to the Chinese people and practically to the people of northern China — meant that alarm bells rang in Beijing, and Communist Party leaders set about trying to remedy the problems along the river. They still face a difficult task.
In this five-part series, NPR takes a journey along the Yellow River and examines the myriad contradictions and challenges that lie ahead.
Problems at the Source: Part 1 starts where the river starts — high on the Tibetan Plateau. Here, Tibetan herders have grazed their animals for centuries. But now, low rainfall, overgrazing and climate change that has thawed the permafrost and the glaciers have all damaged the environment around the river's source and decreased the level of water flowing down from the plateau. So the Chinese government has taken drastic action to try to stop the continued erosion at the source. It has resettled Tibetan herders in brick houses, transforming their centuries-old way of life, in an effort to combat the river's problems.
Pollution: Part 2 looks at the poisoning of the Yellow River. As the river sweeps down off the Tibetan Plateau, it begins to pick up its famous yellow color from the surrounding loess soil. The landscape and the peoples change, too: The Buddhism of the Tibetans on the plateau gives way to the moderate Islam of Hui Muslims, descendants of Persian traders who settled centuries ago around the cities of Lanzhou and Yinchuan. The river itself has also picked up huge amounts of pollution from the industrial zones in inland China, and much of the water is unusable. The government is attempting to address the problem, but with more jobs needed simply to keep a restive population happy, environmental control is proving to be a problem. Now, nongovernmental organizations have sprung up, too, to try to help combat the issue.
Water Shortage: Part 3 examines the water emergency that has developed in northern China. More than 140 million people in the area depend on the Yellow River for their water supplies, and more than 50 percent of the river's water goes to human consumption — a proportion higher than any other river in the world. Everywhere along the river, there is a shortage of water — and the government is preventing more water from being taken from the river, for fear that it will dry up again downstream.
Cradle of Civilization: Part 4 focuses on the importance of the Yellow River in Chinese culture. Chinese civilization grew up along the Yellow River, but it eventually became a symbol of the isolated, backward-looking impetus among the country's leaders that began to hold China back. Now, inland cities along the river are undergoing something of a renaissance, with software companies and other modern industries relocating there. Even the old Communist Party bases are embracing market reforms, as Chinese people become more proud of their heritage, traditional and Communist.
Looking for a Solution: Part 5 reports on how the government is trying to solve some of the Yellow River's problems. For centuries, humans had to be protected from the Yellow River's vicious floods. Now through dams and engineering, the river has been tamed. Some say it is the river that now has to be protected from humans, and northern China's water shortage is testament to the river's overuse. To try to solve the water shortage, the Communist Party has begun the world's largest water project, aiming to channel billions of gallons of water from the Yangtze River in the south to the gasping cities of the North China Plain.