Why Was the Three Gorges Dam Built? A Model Essay on Three Gorges Dam

Students searching for an essay on Three Gorges Dam usually find one of two things: a list of record-breaking numbers with no argument, or an angry piece that treats the dam as pure disaster. Neither earns a good grade. Teachers assign this topic because it forces you to weigh a real trade-off, and weighing is the skill they are grading.

The model below is written for high school and early college courses in geography, environmental science, and general composition. Read it once for the content. Then read the margin notes, which explain how the essay turns a pile of facts into a position you can defend.

The Essay: Why the Three Gorges Dam Was Built and What It Cost

The Three Gorges Dam is the largest hydroelectric project ever built, and it is also one of the most argued over. It stands across the Yangtze River at Sandouping, in Yiling District near the city of Yichang in China’s Hubei Province, where the river leaves the narrow gorges and spreads onto the plains. China built it to do three jobs at once: hold back the floods that have killed people along the Yangtze for centuries, generate enormous amounts of electricity without burning coal, and make a difficult river navigable for large ships. The dam has delivered on much of that promise. The problem is that the bill for those benefits was paid by a different set of people than the ones who collected them, and that imbalance is what makes the Three Gorges Dam worth studying rather than simply admiring.

The idea is older than the People’s Republic. In 1919 Sun Yat-sen proposed damming the river below the Three Gorges in his plan for China’s industrial development. War, revolution, and economic turmoil pushed the project back for decades, and it was debated fiercely within China before approval. Construction finally began on December 14, 1994. The main dam structure was completed in 2006, the power station reached its full planned capacity in July 2012, and the ship lift, the last major component, was finished in 2015. A project imagined in one century was completed in the next, which tells you how much the Chinese state wanted it and how hard it was to build.

The scale explains the ambition. The power station’s installed capacity of about 22,500 megawatts makes it the world’s largest, and in strong-flow years it has set records for annual generation. Each unit of that electricity replaces power that would otherwise come mostly from coal, the fuel that still dominates China’s grid. For a country trying to cut air pollution and carbon emissions while supplying factories and cities, a single plant that produces this much clean power is not a vanity project. It is a serious piece of energy policy.

Flood control, however, was the reason the project survived its critics. The Yangtze is a seasonal river fed by monsoon rain, and the land downstream holds some of China’s largest cities, including Wuhan, Nanjing, and Shanghai, along with much of its industry and farmland. The floods of 1998 affected millions of people, killed well over a thousand, and caused losses in the billions of dollars. The dam’s reservoir is designed to hold back part of the summer surge so that the river below carries less water during the worst weeks. In the summer of 2020, when heavy monsoon rain brought the worst flooding on the Yangtze since 1998, operators opened spillway gates to manage the reservoir while still holding back a share of the peak flow. The dam did not stop the flooding, and nobody serious claimed it could. It reduced the volume reaching downstream cities, which is what it was built to do.

The third job, navigation, is the one people forget. Before the dam, the gorges were dangerous water with fast currents and rocky channels. The reservoir raised and calmed the river for hundreds of kilometers upstream, allowing larger cargo ships to reach Chongqing, one of China’s biggest inland cities. A five-stage ship lock and, later, the ship lift carry vessels up and down the height of the dam. For the economy of the upper Yangtze, this change in shipping was as important as the electricity.

Then comes the other side of the ledger. To fill the reservoir, the river had to rise over a stretch of more than 600 kilometers, and everything in that stretch went underwater. Cities, towns, and well over a thousand villages were flooded along with farmland, factories, and archaeological sites. Roughly 1.3 million people were relocated. Some moved to new towns built on higher ground nearby; others were sent to distant provinces. The government paid compensation and built housing, but the people who lost ancestral land and local livelihoods were not the same people who gained a safer Wuhan or a brighter Shanghai. That is the core of the controversy, and it cannot be waved away by pointing at the generating capacity.

The physical environment changed too. Slopes along the reservoir became less stable once the water rose and began to fluctuate with the seasons, and landslides have been a recurring problem in the reservoir area. Sediment that the Yangtze once carried downstream now settles behind the dam, which means the river below has less silt to rebuild its banks and its delta. Wastewater and industrial runoff that a fast river used to flush out now linger in slower, deeper water. And the Yangtze basin, home to hundreds of fish species, has been hard on its most vulnerable animals: the baiji river dolphin has not been seen in years and is considered functionally extinct, and the Chinese paddlefish was declared extinct in the early 2020s. The dam is not the only cause of those losses, since overfishing, shipping, and pollution all played a part, but it altered the river’s flow and blocked migration routes that these species depended on.

So what is the fair verdict? The Three Gorges Dam does what its planners said it would do. It generates clean power on a scale no other single plant matches, it has reduced flood peaks in a basin where floods have historically been deadly, and it opened the upper Yangtze to modern shipping. Those are not small achievements. But the project also shows the pattern that follows every megaproject: concentrated costs and spread-out benefits. A farmer who lost a village near the reservoir bears a personal, permanent loss; a family in Shanghai gains a slightly lower flood risk they will never consciously notice. Engineering can calculate the megawatts. It cannot settle whether the trade was just.

That is why the dam remains controversial two decades after it began operating, and why it should. Any country planning a project of this size, whether in Asia, Africa, or South America, will look at the Three Gorges Dam as both proof of what is possible and warning of what it costs. The honest conclusion is not that China was right or wrong to build it. It is that the dam succeeded on its own terms while creating losses that its terms never counted.

Three Gorges Dam Controversy: Why the Essay Puts Advantages First

The strongest move is the structure: purpose first, costs second, judgment last. Many students write the controversy paragraph first because it feels dramatic, and then the essay has nowhere to go. By explaining what the dam was supposed to do before criticizing it, the writer earns the right to criticize.

The second move is restraint with numbers. The original sources on this topic are full of figures, and many of them conflict. The essay keeps the handful that can be checked, the location, the timeline, the installed capacity, the 1.3 million relocated, and lets the reasoning do the rest.

The third move is honest causation. The paragraph on species loss says the dam “is not the only cause.” That one phrase signals to a teacher that the writer understands how environmental systems work.

Writing Your Own Essay on the Three Gorges Dam Negative Effects and Advantages

Start by deciding your position on the trade-off. If you cannot finish the sentence “The Three Gorges Dam shows that ___,” you are not ready to draft. Our guide to writing a thesis statement walks through that step.

Then pick your evidence by purpose. One paragraph each for flood control, power, and navigation gives you a spine. Add one or two paragraphs on costs: resettlement, landslides and sediment, river ecology. If your assignment is a cause-and-effect piece, the causal analysis essay guide shows how to chain those effects without blaming the dam for everything.

Finally, check every figure against a reliable source before it goes in. Encyclopedias, government reports, and university pages are safer than listicles. For a comparison, see how our global warming essay example handles a topic where numbers are everywhere and credibility depends on choosing the right few.