The 1000 years flood proof system that still works today

If you build a city at the confluence of two rivers, you can harness the water to irrigate farmland, develop fisheries, and become a prosperous land of abundance. But whenever the rainy season comes, rising river levels turn the city and fields into a vast ocean, wiping out years of hard work in an instant. So, you think of building tall city walls. While they block the floods, rainwater inside the city has nowhere to drain. You then design underground drainage pipes at the

base of the walls. But if the river rises higher than the outlets, water flows back into the city, making things worse. To solve this, you place a wooden flap over the outlet. When water inside is higher, the pressure pushes the flap open to let it out. When outside water is higher, it presses the flap shut, blocking backflow. Problem solved. But what if the river outside never drops? The city's water would still have no escape. So you dig a net

of intersecting channels inside the city, leading to reservoirs and ponds in low-lying areas. These store excess water during floods and supply irrigation during droughts. To keep the system running smoothly, you also add sedimentation wells at key points to catch heavy sand and debris, and iron grates at corners to trap lighter floating waste. With regular cleaning, the whole system remained stable for centuries. Since the two rivers were called the Zhang and the Gong, their confluence was named the Gan River. This city became Ganzhou, and because the channel layout resembled the calligraphic strokes of the characters for fortune and longevity,

The system was named the Fushou Ditch. Congratulations, you just built the thousand-year flood-proof drainage system of Ganzhou. Born in the Song Dynasty, this underground water management wonder still works today. Its harmony with nature inspiring modern flood control systems worldwide.