Two high-resolution bathymetry investigations of Lion City

The geological and hydrological pressures were generally neglected primarily due to the challenging nature of the monitoring task in an underwater setting, particularly over a large-scale region. Using repeated multibeam sonar measurements, we developed an uncertainty-based approach for interpreting the geomorphic change of the Lion City, an ancient Chinese city that is submerged in Qiandao lake. Repeated topographic surveys with a 14-year interval coupled with underwater video and photography data revealed that instead of the anthropogenic and biochemical pressures, the instability of the hill slope adjacent to the city poses an imminent threat to the heritage.