Climate impacts and conservation challenges
Dr. Phan Thanh Hai, Member of the National Cultural Heritage Council, Director of the Department of Culture and Sports of Hue City, said that according to actual surveys and historical documents, the Hue Imperial Citadel wall system has a total length of about 2,416m, an average height of 4m, and a thickness of 1m. The wall body consists of three structural layers, including two outer layers of bricks and a layer of clay in the middle.
Over the past two centuries, under the impact of the harsh climate of the Central region, especially the prolonged rains, the wall has continuously absorbed water, leading to expansion and loss of durability. The collapse of the Imperial Citadel wall is not an isolated event, but a specific manifestation of the impact of climate and the limitations of traditional conservation measures in a changing natural context.
A section of Hue Imperial Citadel wall collapsed in the recent floods.
The three-circle system of the Citadel, the Imperial City and the Forbidden City represents the philosophy of feng shui and the pinnacle of construction technology during the Nguyen Dynasty. Since the complex of Hue Monuments was recognized by UNESCO as a World Cultural Heritage in 1993, conservation work has always been focused on.
The Citadel, with a perimeter of more than 10,000m, has been renovated in many sections, especially the 10 gates which have been almost completely restored. The Imperial Citadel wall system has also been reinforced and the gates (Ngo Mon, Hien Nhon, Chuong Duc, Hoa Binh) and three main platforms in the East, West and North have been restored.
Dr. Phan Thanh Hai emphasized that, in the immediate future, it is necessary to establish a monitoring and early warning system for the entire Imperial Citadel wall, especially the sections adjacent to Ngoai Kim Thuy Tri moat. Deploying sensors to measure humidity, tilt, and groundwater pressure, connected to the Heritage Monitoring Data Center, will help detect the risk of deformation or collapse before an incident occurs, moving from a passive state to a proactive response.
In addition, comprehensive geotechnical and hydrological studies are needed to assess the impact of Ngoai Kim Thuy Lake water levels and the urban drainage system on the foundation of the citadel wall. This will help to map heritage risks, identify points that need urgent reinforcement and areas that need drainage system improvement.
Solutions for conservation and sustainable development
According to Dr. Phan Thanh Hai, an important approach is to combine traditional materials and modern technology. Lime, molasses, and bricks are traditional materials that can be improved with nano-silicate binders or biological additives to increase moisture resistance while still maintaining the ancient look.
When restoring collapsed and tilted wall sections, the mortise and tenon technique helps stabilize the structure, an experience that has been successfully applied in the North, East and West Khuyet Dai. At the same time, Heritage BIM will digitize the entire structure, save technical records, restoration history and current status, creating a long-term scientific management foundation.
Preserving the Imperial Citadel wall also needs to be linked with ecological planning and urban landscape. Building a "safety belt" and anti-erosion buffer zone around the citadel moat, applying aquatic vegetation, permeable cobblestones, and drainage retaining walls, both reduces water pressure and creates a harmonious ecological landscape, in line with the orientation of "Hue - green, heritage, smart city".
Heritage is only sustainable when it is associated with the community. Households around the Imperial Citadel need to be trained to identify early signs of danger and form a "community heritage monitoring" group. Expanding cooperation with international organizations such as UNESCO, WASEDA (Japan), KOICA (Korea), the French Institute for Heritage Conservation (INP) and experts from Germany helps Hue access advanced technology and experience.
Dr. Phan Thanh Hai shared that in the long term, the program "Hue - Climate-Resilient Heritage City" should be included in the Heritage Urban Development Strategy for the period 2025-2035. This is a commitment to turning heritage into a center of sustainable development, where science, technology, tradition and community blend together.
"The collapse of the Imperial Citadel wall is a stern warning, and at the same time an opportunity to review how to preserve heritage in the new era. When ancient walls can "breathe" with the climate, are monitored by technology, protected by the community and placed in a green development vision, that is when heritage can truly revive and be sustainable," Dr. Phan Thanh Hai emphasized.
As reported by Health & Life Newspaper, at around 6:45 p.m. on November 2, a section of the northern wall of the Imperial Citadel collapsed, adjacent to Dang Thai Than Street, about 180 meters east of Hoa Binh Gate.
The collapsed section of wall is 14.2m long, about 4.3m high on average, and shows signs of subsidence. This location was originally a section of the Imperial Citadel wall built with traditional bricks and lime mortar, with a three-layer structure.
Preliminary assessment of the cause is due to the impact of rainwater seepage, prolonged flooding causing erosion of the wall base and fluctuations in water pressure inside and outside the wall. The wall has degraded over time, affected by weathering, tree roots and partly affected by external traffic vibrations.
On November 20, the People's Committee of Hue City decided to declare an emergency situation regarding the collapse of a section of the Imperial Citadel wall.
Source: https://suckhoedoisong.vn/thach-thuc-bao-ton-di-san-truoc-thien-tai-tu-vu-sap-tuong-hoang-thanh-hue-169251125075109092.htm
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