Ancient drainage system ensures Zhangbi Castle weathers the storm

After torrential rainfall swept through the region recently, the ancient drainage system of Zhangbi Castle in Jiexiu city, Shanxi province, continued to function flawlessly — a testament to the ingenuity of craftsmen who worked in harmony with nature and adapted their designs to suit local conditions.

Wang Aiyuan, a 65-year-old researcher on Zhangbi Castle, said that the fortress sits on terrain that slopes downward from south to north, surrounded by ravines on three sides and backed by a mountain on the fourth. This natural elevation difference allows rainwater to flow downhill effortlessly with gravity, providing the ideal topographical conditions for the entire drainage network.

With a history spanning over 1,600 years, Zhangbi Castle was a small military fortress before it was turned into a civilian settlement. In 2012, it was selected as one of China's first "traditional villages".

"The ancient people of Zhangbi followed nature — they channeled water rather than blocking it," said Wang, who has devoted years to studying the fortress' cultural heritage. This time-tested drainage design effectively prevents rainwater from directly eroding building foundations and courtyard walls, significantly reducing water damage to ancient structures and extending the lifespan of traditional dwellings. The result is a remarkable "dry roads as soon as the rain stops" effect.

"Even during heavy flood-season downpours, the walkways on both sides of the fortress remain passable for residents and tourists alike," he added.

In the wake of the Northern Song Dynasty (960-1127), Zhangbi Castle gradually transformed from a military garrison into a village. Over the past millennium, local residents have continuously refined and improved the drainage network during village renovations, ensuring that this ancient hydraulic engineering marvel can remain active.

Currently, 50 to 60 traditional residences within the fortress are awaiting restoration. All renovation work strictly adheres to the original architectural framework — no arbitrary elevation changes or alterations to the existing terrain are permitted, preserving the fortress's authentic appearance to the greatest extent possible.