Top 10 Ancient Agricultural Sites Most Dependent on Precipitation

The irrigation system of Angkor was more than the lifeblood of the Khmer Empire; it was a grand experiment in resilience against climate volatility. Renowned for its incredibly precise gradient engineering—with a drop of only a few centimeters per kilometer—this system utilized massive reservoirs (Barays) to regulate monsoon rainfall. Its ingenuity lay in its dual function: it channeled excess floods during heavy rainfall years to prevent collapse, yet stored enough water to sustain tens of thousands during prolonged droughts. In contrast to modern reservoir systems that often struggle with extreme climate shifts, Angkor’s network thrived for centuries until it was finally overwhelmed by the 'mega-droughts' and erratic seasonal floods of the 15th century, serving as a sobering testament to how climate can dictate the rise and fall of civilizations.