White Crane Ridge: The Great Underwater Wonder
Today, we’ll introduce you to the world’s oldest hydrographic station that measured water level changes in the Yangtze River for more than 1,000 years. It’s located in southwest China’s Chongqing Municipality, and as a precious cultural relic, the site was turned into the world’s first underwater museum.
Baiheliang, or the White Crane Ridge, is a long stone ridge in the upper reaches of the Yangtze River in Fuling of southwest China’s Chongqing Municipality. Believed to be the world’s oldest hydrographic survey station, it dates back to the Tang Dynasty around 1,200 years ago.
It’s said that White Crane Ridge gets its name because of the many white cranes that flock there in the autumn and winter. But some local people believe that a Taoist who used to meditate there finally achieved immortality and transformed into a crane. Whatever the case, the site has long endured as one with a deep connection to the inhabitants of the region.
During the dry seasons, usually from December to March, ancient Chinese would gather on the 1,600-meter-long outcropping with its average width of 15 meters to enjoy picnicking, flying kites, and playing games.
Since the year 763, people started to carve fish shapes onto the stone ridge to record the lowest water level of the year. Throughout the ages, people continued to carve the dates upon which the fish carvings would first become visible, as well as the distance of the low water line to the fish carving, and even descriptions of the scene in the form of poems.
Based on these engraved inscriptions, the ancient Chinese already calculated a 10-year wet-dry cycle of the Yangtze River. The fish carving would become visible when the water receded, and this would indicate the end of the dry cycle. The next year, there would be ample rain followed by a bumper harvest. A local proverb goes, “Out of the water appear stone fish, out of the field come rich crops”.
As the only well-preserved ancient hydrological station in the world, White Crane Ridge bears 165 surviving sections of carved inscriptions, including 18 fish, two Guanyin bodhisattvas, and one white crane. Among the various sections, 108 are of important scientific value, providing authentic and reliable data to the historical study of the hydrographic variations of the Yangtze River, indicating historical patterns of regional and global climate change.
The hydrological data at the site collectively offer significant guides for not only inland navigation, farmland irrigation, urban water supply, and flood control along the Yangtze River Basin, but also for mega water conservancy projects such as the Gezhouba Dam, the first hydropower station on the Yangtze River built during the 1970s and 1980s, and later the world’s largest hydropower station – the Three Gorges Dam.
In addition to its scientific value, the White Crane Ridge inscriptions also boast important historical and artistic value, showcasing a collection of works by generations of exceptional calligraphers and poets. More than 300 literati since the Tang and Song dynasties have left over 30,000 characters, exhibiting a full spectrum of the different schools and styles in Chinese calligraphic arts. The most celebrated works were carved by Song Dynasty statesman and literary master Huang Tingjian when he was demoted to the area around the year 1100.
The White Crane Ridge Inscriptions were recognized as a key national cultural relic in 1988. But soon its existence faced a critical challenge, with the country’s decision to build the Three Gorges Dam in 1992. According to the construction plan of the world’s largest hydropower project, normal water levels would be raised to 175 meters above sea level, which meant that the White Crane Ridge would be submerged around 40 meters under water.
Conservation of the inscriptions became a tough issue for discussion and research among experts because it was extremely demanding from a technical perspective. Seven protection schemes had been proposed over nine years before one was finally adopted in 2001. The idea came from an academician with the Chinese Academy of Engineering named Ge Xiurun. Professor Ge worked out a plan for an in-situ underwater museum to be built to preserve valuable cultural relics and historical sites.
Under this plan, the stone ridge was enclosed in a huge arch-shaped glass container, which is filled with purified water to reduce erosion of the inscriptions as well as to equalize the pressure on the inner and outer sides of the container. A corridor was built inside the container enabling visitors to view the underwater inscriptions through observation windows.
It took seven years from 2003 to 2009 to complete the construction of the White Crane Ridge Museum at a total cost of 193 million yuan, or about 30 million USD. As the world’s first underwater museum, it covers an area of 11,300 square meters and is comprised of an onshore exhibition hall and an underwater space. Visitors can start from the exhibition hall to obtain a brief introduction of the great underwater wonder before they descend via a 91-meter-long escalator into the underwater space. By walking through the 68-meter-long circular corridor, visitors can appreciate the stone carvings and inscriptions through 23 observation windows. This is the middle part of the stone bridge, where more than 140 sections of carvings and inscriptions are preserved.
In the early days, the museum had to be shut down periodically due to the deteriorating water quality in the container and the rapid growth of algae on the stone ridge. But now, an advanced water recycling system automatically purifies the water and balances the water pressure within the container. The arched covering of the container is made of a special kind of steel that offers protection from ships weighing up to 4,000 tons. The container is also equipped with an energy-saving deep-water lighting system to improve the presentation of the inscriptions and reduce power consumption. Twenty-eight remote-controlled cameras are installed outside the observation windows enabling visitors to zoom in on the details of the inscriptions using touchscreens. Thrill-seeking visitors are even allowed to go scuba diving within the container to examine the stone carvings up close.
At present, the world is paying increasing attention to the conservation of underwater heritages. Outside China, Egypt, Greece, and Mexico are all planning to build underwater museums. Within China, underwater relics such as the Rock Gate and Cliffside Inscriptions in Shaanxi Province, the Xifengkou Section of the Great Wall in Hebei Province, and the 1,300-year-old Lion City under Qiandao Lake in Zhejiang Province are also confronted with similar conservation challenges. In this sense, the conservation and utilization of the White Crane Ridge has opened a new perspective for the world.
In 2008, the White Crane Ridge was included on the Tentative List to become a UNESCO World Heritage. In a recent interview with NewsChina, Yang Bangde, curator of the White Crane Underwater Museum, revealed that China is promoting a campaign to apply with Egypt for a joint World Heritage listing.
Similar to what the ancient Chinese did, ancient Egyptians built instruments called nilometers to measure water levels of the Nile during the annual flood season. This was in turn used to forecast the harvest and tax revenues for the following year. The utilization of nilometers was traced back to 5,000 years ago and came to become a vital instrument for the ancient Egyptian civilization. The 9th-century Raoudha nilometer in Cairo joined the Tentative List to become a UNESCO World Heritage in 2003.
In terms of why the White Crane Ridge is joining nilometers in applying for the UNESCO World Heritage listing, Yang explained that the two hydrological relics located along two of the world’s greatest rivers manifest the importance of river resources for the two agricultural civilizations on different continents. As a testimony of the longest-enduring human-water relationship in the ancient world, they represent the wisdom of early agricultural civilizations in water level measurement and water utilization and offer detailed scientific information on climate change over thousands of years. According to Yang, the joint application will help promote exchanges and mutual learning among civilizations and develop a new model for world heritage conservation.
Two years ago, Peking University’s School of Archaeology and Museology joined UNESCO’s World Heritage Institute of Training and Research for the Asia-Pacific Region in completing two research projects on the White Crane Ridge to explore the feasibility of a joint application.
Currently, preparations for the joint application are underway. China and Egypt are working to establish a regular mechanism for inter-governmental and non-governmental cooperation, and efforts have been made to initiate work on the joint application documents as soon as possible.
For the past millennium, the White Crane Ridge has been the epitome of an underwater wonder with its ingenious carvings and inscriptions, authentic water level records, and rich historical and artistic value. The hydrological data recorded on the White Crane Ridge has indicated predictable hydroclimatic patterns on the upper reaches of the Yangtze River – a minor dry cycle every three to five years, a severe dry cycle every 10 years, and an extreme dry cycle every 600 years.
In recent years, the frequent occurrence of extreme weather has led to increasingly severe natural disasters. These patterns may still be relevant today and spark ideas for humanity to tackle the increasingly frequent occurrence of extreme weather and natural disasters in the future.
Well, that’s the end of our podcast. Our theme music is by the famous film score composer Roc Chen. We want to thank our writer Lü Weitao, translator Yang Guang, and copy editor Pu Ren. And thank you for listening. We hope you enjoyed it, and if you did, please tell a friend so they, too, can understand The Context.