三峡地区城市与河流关系的时空演化研究

主要采用历史文献和城市沿革分析，对314BC-AD2013 年间三峡地区城市与河流关系的时空演变特征进行宏观分析，结果表明：从时间演变看，战国西汉时期，三峡地区城市主要沿长江干流缓慢增长；东汉隋唐时期，三峡地区城市由长江干流向支流迅速蔓延；宋元明清时期，三峡地区城市沿长江干流调整稳固；民国以来，三峡地区城市主要依托重庆、宜昌两市极化增长；唐代是三峡地区城市发展的分水岭，明清是三峡地区城市格局的成型期，现代则是三峡地区核心城市的极化期。从空间分布看，2300 年来，以城址论，三峡地区共出现过61 个城市，其中71%的城市分布于长江干流沿岸，73%的城市分布于两河交汇处，82%的城市分布于海拔300 m以下的河谷地带，小河流域城市多从河流下游向上游拓展。总体来看，三峡地区的城市发展体现了其由易到难、由低到高、溯江而上的区域开发时序。

A research on the spatial-temporal process of relationship between cities and rivers of the Three Gorges Area

Based on historical documents of urban evolution, this paper makes a macro-analysis of the spatial-temporal evolution of the city-river relationships in the Three Gorges Area during the period 314BC-AD2013. The conclusions can be drawn as follows. From temporal evolution, in the stage from the Warring States to the Western Han Dynasty (475BC-AD8), cities in the Three Gorges Area grew slowly along the Yangtze River Mainstream; in the period from the Eastern Han to Sui and Tang dynasties (25-906), cities there spread rapidly from the Yangtze River Mainstream to its tributaries; in the epoch from the Song through Yuan and Ming to Qing dynasties (960-1911), cities there consolidated their distribution mainly along the Yangtze River Mainstream; and since then, from 1912 to 2013, cities there increased aggregately around central districts of core cities of both Chongqing and Yichang; therefore the Tang Dynasty (618-906) was the turning point of urban evolution of the Three Gorges Area, while the Ming and Qing dynasties (1368-1911) were the shaping stage of urban pattern, and contemporary era (1912-2013) is the polarization phase of the core cities. In terms of the spatial distribution, according to the site of cities, a total of 61 cities at the county level emerged in the Three Gorges Area during the past 2300 years, of which, 71% were distributed along the Yangtze River Mainstream, 73% on the junction of rivers, and 82% in the valley below an altitude of 300 m. Moreover, the evolution of cities in a small watershed usually tended to spread from downstream to upstream of the river. As a whole, the urban evolution in this area reflects the fact that a region is developed generally based on natural conditions, such as from lower to higher altitude and from downstream to upstream.