Research On The Development Of Water-friendly Cities And Towns In Coastal Areas In The Pre-Qin,Qin And Han Dynasties

In the process of rapid urbanization in my country,water disasters are serious,and many cities are faced with various water problems such as floods,groundwater level decline,and water environment deterioration.Looking at the present,it is good to learn from the ancient.In the process of urban construction in the early Qin,Qin and Han dynasties,a lot of experience with simple ecological value was accumulated in the process of adapting to the water environment.The valuable experience of the relationship provides more perspectives on the layout of contemporary urban water systems,flood control and waterlogging control,and water heritage protection.The coastal areas have various geographical types,rivers and lakes,and coastlines have changed.The early city construction was greatly influenced by rivers and oceans.Taking this as the research object of this paper,the time is defined as the pre-Qin,Qin and Han periods when the city originated.The area mainly includes the coastal areas of the Northeast Plain,the coastal areas of the North China Plain,the coastal areas of the middle and lower reaches of the Yangtze River,and the hilly coastal areas of the southeast.The five selected Wudacheng,Linzi,Shanyin,Yecheng and Panyu are representative of natural and cultural regions.For example,based on historical documents,archaeological materials and historical maps,a multi-scale historical database of water-wading human settlements in coastal areas is constructed.Conduct hierarchical research on the relationship between cities and water in the early stage,sort out the characteristics of water-friendly development of cities and towns,and establish a research framework on the dual scale of regions and cities.At the regional level,the article first discusses the temporal and spatial evolution characteristics of cities and towns as a whole in the region and the relationship between water-friendly construction and development,and then starts from four sub-regions to discuss the interaction and dynamic evolution process of city site selection and development and water environment under different regional backgrounds.On the whole,the horizontal distance between the city and the river is 1000-2000 meters,and the vertical distance is 0-20 meters is the area with the strongest preference.They are mainly distributed around the safer Grade 1 water system,while cities and towns with higher grades are mostly distributed around the Grade 2 and 3 water systems with more abundant water resources.More than 60% of coastal cities and towns are located within 5km of the coastline.For the sub-regions,the coastal areas of the Northeast Plain are affected by the changes of the coastline and politics.The center of gravity of the regional cities changes greatly,and the distribution of directions is not obvious.The cities and towns are mainly concentrated in the eastern edge of the Lower Liaohe River.In the Haidai area,where the geographical advantage is the most,in the early days,due to the swing of the Yellow River,there was no city construction in the eastern part of the Heji Plain,and cities gradually appeared after the Warring States Period.The production and transportation of the sea salt industry developed near the ocean led to the formation of the urban agglomeration system around the Laizhou Bay,but at the same time,some cities and towns were also annihilated due to the influence of transgression;the coastal areas of the middle and lower reaches of the Yangtze River formed lakes such as Taihu Lake and Jianhu Lake as the center of gravity.The city cluster system,the changes of the coastline formed a coastal city system that was prospered by sea salt.The development of artificial water conservancy has formed a city system along the canal that was prospered by water transportation;the coastline of the hilly and coastal areas in the southeast fluctuated significantly,and the center of gravity of the city was significantly shifted,mainly concentrated in the estuary of the Pearl River and the Minjiang River and the impact of various large rivers entering the sea.It is located in the plain,and it is characterized by the river estuary as the point and extending along the river to the surrounding area.At the city level,the water-suitable construction of the central city was sorted out from the aspects of site selection,construction,water management,flood control,and landscaping,and summed up the water-adaptive city site selection under the flood control needs and the city construction under the constraints of the water network.,The three water-suitable characteristics of water conservancy construction under the development needs of cities and towns.The water suitability pattern of central cities is driven by internal and external mechanisms.The demand for flood control is the external mechanism to promote the city’s water suitability.Urban water conservancy construction and urban construction under the constraints of the water network are the internal mechanism of the city’s water suitability.The negative feedback mechanism has gradually formed the water adaptability of the city.The construction experience of regional water resources adjustment thinking,multidimensional and stable water network sorting,and moderate water-adaptive forms in coastal cities and towns are worthy of reference.Contemporary Chinese cities face a more complex water environment,but the urban water adaptability is weak,and the urban flood disaster is serious.The development of ancient cities suitable for water can provide many enlightenments for today.