AS FAR BACK AS 1919 Sun Yat-sen, the father of modern China, proposed harnessing the power of the Yangtze River to manufacture fertilizer to help feed his nation of starving peasants. Almost half a century later Mao Ze-dong swam the river to kick off the Cultural Revolution and blessed plans for a dam that would control the Yangtze’s chronic floods. But it would be another twenty years before Mao’s successors would adopt the longed-for dam as a symbol of China’s resolve to compete as a major power — and alarm the world with their plans.

Designed to supply just ten percent of the country’s electricity, the Three Gorges project was criticized as outmoded technology inadequate to meet China’s needs. The World Bank denied funding, the United States and Canada withheld support, and inside China journalist Dai Qing published Yangtze! Yangtze!, a book of antidam criticism (and was jailed for her effort). Dams this large are economically unsound and magnets for corruption. Dams this large are too often environmental disasters. Despite protests, in 1992 the People’s Congress approved the final design for a structure taller than San Francisco’s Golden Gate Bridge, as well as the world’s largest power plant and the highest ship locks ever built. Construction began a year later.

The Yangtze River is China’s Golden Waterway, carrying three-quarters of the country’s water-borne traffic. One-third of the people alive in China today live along the river, many in the 130 towns and 300 villages threatened by the rising water. Fengdu, the Ghost City, where pilgrims have traveled for centuries to bribe the God of Hades for safe passage to the hereafter, will be lost forever, as will be portions of old-town Chongqing, Chiang Kai-shek’s nationalist headquarters during World War II, and villages like Xiling, where the local party secretary abandoned his ancestral home as an example to his neighbors, even though his house lies above the waterline.

Enriched by silt that the river has traditionally deposited in its middle and lower reaches, the Yangtze basin produces fifty percent of China’s cotton and seventy percent of its grain, crops the government insists will now be protected from flooding by the wall of concrete. Upriver in the Three Gorges over half a million acres of agricultural land will be lost to the reservoir. North of the river the country is dry, but in the south the Chinese have battled floods for centuries — 150,000 people dead in 1931 and over seven million acres of farmland inundated; less than a quarter-century later another 40,000 lives were lost. As recently as 1998 the river left five million homes and fifty-four million acres of farmland in ruin.

In the fourth century the mysterious Ba People settled the Yangtze basin, but these are ancestors modern residents will never know. Ba coffins, which once hung tantalizingly above the rapids in the Three Gorges, now rest safely in museums, but ancient Ba villages have been abandoned to the rising water. In all over eight thousand unexcavated archeological sites will be submerged, including more than thirty dating back to the Stone Age, and stone carvings from the time of Christ. Temples from the prosperous and sophisticated Ming Dynasty are already under water.

The Yangtze’s people once believed that the floods that vexed them were caused by dragons, and that a pagoda built on a hilltop could protect a town from being swept away. Today the steadily rising reservoir laps at these elaborate gilded towers, promising a still lake where the river once roared. In Wanxian 800,000 residents have been forced to move, some from homes their families have occupied for generations. In exchange the government has promised a railroad to expedite access to commercial markets and an airport with runways long enough to handle jumbo jets. Many of the one and a half million people the water has displaced have moved farther up the steep riverbanks into a treeless landscape of government housing. Others, though they lack skills and education, have heeded the government’s call to abandon the river for the coast, where there is supposedly a labor shortage. All this is considered a small price to pay for protecting those living downstream of the dam.

In a country where there are no agencies to plead the people’s case, no forum for open debate, it was easy enough for the government to disregard engineers who predicted that the new dam will silt up like Mao’s failed Sanmenxia Dam across the Yellow River — that its generators will clog and its reservoir will be reduced to a muddy quagmire. And too easy to turn a deaf ear to those who worried that the Baiji river dolphin, already extinct elsewhere in China, will now be lost along the Yangtze, in company with the white crane, the prehistoric sturgeon, and river otters that for centuries have guided Yangtze fisherman to their catch.

It is difficult to visualize a way of life gone forever, knowledge and insights that have been passed down over generations. A trip up the Yangtze two months before work began on the final section of the dam revealed a farmhouse with its thatched roof gone and only dry remnants of last year’s crop left in the fields. Around another bend an orange grove appeared, a thin strip of cultivation whose destiny was advertised by red-lettered placards announcing the final fill level of the dam’s reservoir. In Wanxian hangers-on cooked rice on open fires at river’s edge amid piles of broken concrete and twisted rebar. The government promised that the debris would be removed ahead of the rising water, but many worry that the reservoir will be polluted by refuse from abandoned factories (nine hundred industrial buildings were located below the new waterline in Wanxian alone) and by years of human waste leached into the riverbed.

When the reservoir nears its final level this December, twenty-five miles of cliffs that form Witches Gorge, a river canyon so narrow the sun rarely reaches the water, will be slashed off at their knees. Hand-hewn footpaths that carried centuries of travelers will be lost under water along with figures etched into the rock face to record the water level during years of floods. Cloud-shrouded cliffs that have inspired centuries of poetry and art — four-thousand-foot-high peaks famed for their dark and sober grace — will look like stumps.

To commemorate his river swim, Chairman Mao wrote a poem that glorified his vision of a dam that would bury the most scenic of the Yangtze’s landscapes. “Walls of stone will stand upstream…” he wrote, “Till a smooth lake rises in the narrow gorges / The mountain goddess if she is still there / Will marvel at a world so changed.”