TOEFL統合ライティング

📖 読解文章

The recent discovery of a large-scale irrigation system in the ancient city of Angamala, located in a semi-arid region of South Asia, has led some archaeologists to propose that this civilization was far more technologically advanced than previously thought. The system, dated to around 2000 BCE, consists of a network of canals, reservoirs, and sluice gates that appear to have been designed to manage seasonal monsoon rains. Proponents argue three main points. First, the complexity of the engineering—such as precise gradients and interlocking water storage—indicates a sophisticated understanding of hydraulics, which would have required mathematical knowledge and centralized planning. Second, the scale of the system, covering over 500 hectares, suggests that the state had the administrative capacity to organize labor and resources on a massive scale, implying a strong centralized government. Third, the presence of sluice gates with movable wooden parts points to a deliberate strategy for flood control and drought mitigation, which would have required long-term climatic forecasting and adaptive management. These features, supporters claim, place Angamala on par with other early hydraulic civilizations like Mesopotamia and the Indus Valley.

🎧 リスニング講義

However, recent fieldwork by a team of hydrologists and archaeologists challenges these interpretations. The professor argues that the apparent 'sophistication' may be a misreading of natural formations. First, the so-called 'canals' are likely ancient riverbeds that were naturally carved by seasonal floods. The gradients and interlocking patterns are typical of braided river systems, not human design; no evidence of linings or tools used for excavation has been found. Second, the 'reservoirs' are actually natural depressions, possibly formed by tectonic activity or erosion. Their distribution across 500 hectares does not imply central planning; rather, they are scattered and irregular, which would be inefficient for irrigation. Third, the 'sluice gates' are merely rocks that have fallen into narrow channels, creating natural dams. There is no trace of wooden structures or human modification at these sites. The professor concludes that while Angamala was a significant settlement, its water management was likely opportunistic, relying on natural features, not advanced engineering. Thus, the evidence does not support claims of technological superiority or centralized state control.