China's unquenchable thirst: China's staggering growth over the last 20 years has strained much of its resource base, but nothing more than freshwater supplies.

• Author: Postel, Sandra

On June 8,1988, I boarded a midnight train bound for Zhengzhou from Beijing, where my trip to research China's land and water challenges had begun just three days before. My senses were already brimming with the sights and sounds of the capital city and its surroundings--horse-drawn carts piled high with bricks, waves of wheat awaiting harvest, bustling markets along dirt roads, and bicycles, bicycles everywhere. Under China's "responsibility system," farmers were now allowed to sell whatever they harvested above their quota to the state. Colorful roadside stands laden with melons, fruits, vegetables, and meats were sprouting like weeds after a long winter. Many farmers suddenly had money to build new houses, and signs of a construction mini-boom were unmistakable. This, of course, was just the tip of the iceberg: soon enough China's cities would catch the market-economy wave and ride it headlong into the globalized world of the 21st century.

It was clear even then, nearly 20 years ago, that the availability of freshwater posed a major challenge to China's future. China was home to 21 percent of the world's people but only 8 percent of its renewable water supply. Most of that water was in the south, making the north even more water-short than the national figures suggested. Water tables were already dropping as much as a meter a year in parts of the North China Plain, a major grain-producing region. The overpumping of groundwater in Beijing's eastern suburbs was causing the land itself to subside as much as 10 centimeters annually.

So as the train left the Beijing station and rolled past the Great Hall of the People, brightly lit in the dark of night, I was already wondering what China's water officials would do. Two days before, I'd met Dr. Li Xuinfa, director of the Institute for Research on Environmental Protection, who stunned me by presenting me with a Chinese version of my 1984 World-watch paper, Water: Rethinking Management in an Age of Scarcity. The 60-page paper, which Dr. Li had translated and was planning to have published in China, called for a fundamental shift away from big, ecologically destructive water supply projects and toward conservation and efficiency improvements--not a popular idea back then. But I wondered how much traction it would get in China.

I fell asleep quickly, lulled by the sound and motion of the train. I intended to awaken early so as not to miss a main attraction (at least for me), the crossing of the...