Author | Raquel C. Pico

Recognized as one of the monumental engineering achievements of modern times, the Three Gorges Dam, in China, harnesses the immense power of the Yangtze River and its colossal scale is such, that it can be seen from space.

The construction of the Three Gorges Dam was driven by practical utility and safety measures. Primarily, the objective was to capitalize on the vast potential of the Yangtze River, one of the world’s longest rivers, for electricity generation. Additionally, the reservoir would provide the means to regulate the river, mitigating the impacts of rising water levels. Flooding had been a longstanding issue, posing significant challenges over the years.

The concept of constructing a dam on the Yangtze River had been circulating for a considerable period. The idea initially emerged at the start of the 20th century, however, it was not until the 21st century that the project came to fruition, following an extraordinary investment and extensive commissioning efforts. It took approximately two decades of concerted effort to complete the task.

It is now one of the world’s most renowned mega-constructions. Determining the largest dam in the world is no simple task due to various criteria that can be considered, but the Three Gorges Dam undeniably stands out as a top contender. In terms of power generation, it ranks at the forefront. The Three Gorges Dam boasts a power generation capacity of 22,500 MW.

The importance of sustainable engineering

But the history of the dam has also highlighted the importance of embracing sustainable engineering practices, and comprehending the environmental ramifications of such mega-constructions. Although hydroelectric energy is considered cleaner in terms of carbon footprint compared to other forms of energy generation, it is not without its environmental impacts. And much more so with large-scale infrastructure projects like the Three Gorges Dam.

Any intervention in river basins has an impact on their biodiversity. Similarly, alterations to water flow have far-reaching environmental consequences, extending beyond the immediate vicinity of the dammed area and affecting downstream water flow and sediment dynamics.

In the case of the Three Gorges Dam, there have been reported instances of landslides, and certain studies have linked the presence of this massive dam to alterations in seismic activity. Similarly, the population of fish in the river has declined, prompting the implementation of fishing moratoriums. While authorities attribute the decline in fish population to prior over-exploitation, fishermen directly attribute the issue to the dam itself, as it hinders fish migration and prevents them from traveling upstream.

In addition to these concerns, there is an ongoing debate regarding the effectiveness of the dam in controlling flooding, a primary reason for its construction. Despite the presence of the dam, numerous instances of flooding have occurred over the years in the Yangtze River Basin.

Urban planning to tackle the challenges

The impact of the Three Gorges Dam extends beyond the natural environment. The massive dam has also influenced urban development in the affected areas. The construction of this infrastructure resulted in the disappearance of two towns, 114 villages, and 1,680 hamlets.

During its years of construction 1.3 million people had to be relocated. However, the population movements did not cease with the commissioning of the dam. Earth movement activities and the ongoing environmental impact led to the relocation of thousands of people from their homes at the beginning of the last decade.

The Chinese authorities promised to relocate those living in the affected area and to build new communities. The process was not always easy. As some residents acknowledged, the decision to move was not optional, and the land to which they were relocated often did not resemble the one they had left behind.

For some families it meant a loss of income and greater economic uncertainty. While authorities provided options for relocation, in some cases, this meant families had to move hundreds of kilometers away from their original region. The compensation received by those displaced was often insufficient, leading to ongoing demands for increased compensation to adequately address the negative impact on their living conditions.

Some estimates suggest that the construction of the dam displaced approximately 3.67 million people directly, while indirectly affecting a further 54.8 million individuals.

The transition was also complex, as it often required moving from rural to urban areas, necessitating a significant shift in lifestyle. It also resulted in the loss of both tangible and intangible assets.

Chongqing, the rapid growth city

By altering the structure and flow of the river, the urban layout along its banks has also undergone changes. The changes to the Yangtze River, including navigation improvements, have benefited the city of Chongqing by reducing freight transportation costs. In recent decades, Chongqing has emerged as one of China’s areas with the highest economic growth rates, propelled by various factors, including industrialization and administrative reforms.

This in turn has led to a rapid population increase: Chongqing is now the largest city in the world by population (i.e., it tops the list if the entire urban agglomeration is not analyzed). However, Chongqing is not an example of urban planning. The city is dominated by large buildings, yet the construction of these structures has often neglected essential considerations such as access to natural light, and urban traffic flow is constrained by the dense clustering of skyscrapers, motorways, and roads. In fact, one of the most iconic and widely circulated images of Chongqing is that of a building pierced by subway lines.

The rapid and explosive growth of Chongqing, coupled with a lack of cohesive urban planning, paves the way for potential future issues related to zoning in the area and the overall quality of life for its inhabitants. Pollution is already a problem. A recent study by the World Bank highlights the challenge of transitioning to a greener energy system. Currently, 75% of the energy used in Chongqing comes from fossil fuels, resulting in a carbon footprint that is eight times higher than that of metropolitan areas like Tokyo and Seoul

Therefore, the key lesson from this project is the imperative of coupling such constructions with a well-defined urban planning strategy, which should incorporate innovative approaches aimed at enhancing the quality of life for residents, They may even be opportunities to experiment with new, more efficient and positive forms of city living.

Image | menabrea/iStock, powerofforever/iStock, urf/iStock, 4045/iStock, CHAO-FENG LIN/iStock

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