A historical study on the patterns of spatio-temporal evolution of towns in the Wuding River Basin

The Wuding River is one of the main branches in the middle reaches of the Yellow River, flowing through the Loess Plateau in northern Shaanxi. This paper analyzes the positions as well as the beginning and ending dates of the counties in the Wuding River Basin, from 300 BC to 1900 AD. Based on the history of administrative divisions, economic and social developments, and regime changes, three spatio-temporal patterns of towns evolution process in this river basin are found: (1) Influenced by the cyclical fluctuation of climate, the rise and decline of towns in the river basin has obvious periodicity, and the geometric center of the towns in this basin has obvious characteristics of tidal movement in a "northwest- southeast" direction. (2) The life spans of the town sites are generally short, and there were four stages with four different central towns in history. The direction and process of the movement of the central towns were consistent with the trend of the tidal movement of the geometric center of the towns. (3) In the history of the river basin, there were three types of towns spatial patterns: along the river valleys in the Qin-Han and Sui-Tang periods, along the border lines and the Great Wall in the Song and Ming periods, and along the lower reaches of the river basin in the Yuan and Qing periods. Based on the analyses, the authors suggest that to rationally determine the scale and layout of the towns system, the future development plan for the Wuding River Basin should focus on the long- term impact of climate change on towns distribution and the reality of regional environmental vulnerability. © 2019, Science Press. All right reserved.