Table 4 Comparison of natural conditions between Nanjing and Xi’an
Region | Topography | Soil | Dynasties | Total duration (years) | Total number of flood events | Frequency of flood events | Data sources |
|---|---|---|---|---|---|---|---|
Nanjing | Low elevation (avg. 8.9 m), dominated by low mountains, hills, and uplands | Mainly yellow-brown and red soils | Eastern Jin, Southern Dynasties, Early Ming | 356 | 109 | Approx. once every 3 years | Book of Jin, Book of Song, Book of Southern Qi, Book of Liang, Book of Chen, History of Ming, Ming Veritable Records |
Xi’an | Weihe Plain at an average elevation of 400–700 m | Mainly yellow-brown and brown soils | Qin, Western Han, Eastern Han | 441 | 15 | Approx. once every 29 years | Records of the Grand Historian, Book of Han, Book of the Later Han, Records of the Three Kingdoms |
