Evidences From Yangsi Water God Temples For Changes Of Hydrological Environment In The Lower Yuanshui River In Qing Dynasty

Based on satellite remote sensing images of the lower reaches of the Yuan River,combined with ancient books,documents,and maps,this thesis makes a large degree of discrimination of ancient river channels and analyzes the distribution of river channel changes from five different historical periods: the late Ming and early Qing Dynasties,the Kangxi period of the Qing Dynasty,the Qianlong period of the Qing Dynasty,the late Qing Dynasty and the 38 th year of the Republic of China(AD 1949).Through the investigation of the value of Yangsi water temple and the positioning of the coastline of Yangsi water temple,the plane shape of the ancient river channel is obtained,and the understanding of the research on river channel change based on the above remote sensing images and ancient books and documents is empirically and corrected.By testing the elevation of the water temple site,26 elevations related to the highest water level of drought and flood in the ancient river are obtained.On this basis,the trend map of the elevation of this kind of Water Temple with time is drawn,which reveals the historical period of frequent flood disasters and the era of reconstruction after the temple is destroyed.The innovation of this thesis is: Taking the Yangsi water temple site as the riverbank demonstration point,the riverway changed map based on ancient literature and remote sensing images is verified.Taking Yangsi water temple site as the highest water level point as the historical water level record to study the changes of ancient water environment,the following conclusions can be drawn:1.The utilization of remote sensing image data can be used to interpret and identify the types and boundaries of ancient rivers better,and to analyze the evolution characteristics of ancient rivers in the Qing Dynasty in Yuan River,and to reconstruct the distribution of ancient rivers in the typical historical period.Landsat 8 multispectral remote sensing data play a significant role in the interpretation of the ancient river channels,and three river channels types are identified through human-machine interaction,based on different vegetation,river and hill types reflecting different morphological features,texture features,and tonal differences in the images,extracting the boundary lines of vegetation types around the river channels.Floodwaters covered the floodplains in front of the mountains,filling up the original channels as well as changing the channels,which makes it difficult to recognize and the historical time-image sequences of river channels can not be detected.Historical documents help to distinguish the time of ancient rivers,especially where there are disputes and misunderstandings in areas of frequent river swings,but the events recorded in the ancient books are inaccurate and the place names are incorrect and are not yet adequate to accurately locate the time and location of the ancient river courses.2.Cultural value and ancient environmental value are the uniqueness of Yangsi water temple.The value of ancient culture lies in that the Yangsi water temple is the traditional cultural belief of the Chinese nation.It has to be built on water.The purpose of the construction is also related to water.First,pray for the safety of navigation at sea;Second,as the meeting place of the shipping terminal;Third,play the role of lighthouses.The paleo-environmental value is to obtain historical hydrologic and tortuous changes from space-time and latitudes by excavating the paleo-hydrologic station and water-level elevation data of the temple site.The 40 water temples surveyed were divided into eight types: stone cabinets,pavilions,temples,monasteries,palaces,temples,nunneries,and towers.Different types have different cultural values and ancient environmental values.Among them,the lower reaches of the Yuan Dynasty stone box have the most important hydrological environment.All the water temples in the fields live on the water.The location of the water temple can distinguish the existing and the historical hydrological environment,namely the existing ancient river shoreline.The results can be used to correct the deficiency of multispectral remote sensing images and ancient books in the study of palaeo-river changes.3.As a passageway for the transportation and trade of ancient materials,rivers dominated the development of ancient economies,population,and societies.To ensure the safety of water transportation,it is necessary to build water navigation aids on shore.As a material transfer point,the two sides of the river naturally form a market.The water temple is a building that integrates water navigation aids and markets.When the river is diverted,a new water temple will be built and the old one will be preserved.Therefore,the area with more water temple ruins is the area where the river flows frequently.The identification of the tributaries in the lower reaches of the Yuan Dynasty can also be made through the value of the river-bank lines of the ancient Yangsi water temple River.Through a comparative study of four examples of Yangsi Water Temple and ancient river channels,we can find the spatial correlation between Yangsi Water Temple and ancient river channels.This water temple is built on water.It can be inferred that the water temple was built when the river existed,and the water temple was destroyed when the river changed.From this,we can know when rivers appear and change.4.Extreme weather events such as droughts and floods are the world's worst natural disasters.The height of the water level can reflect the change of climate from the side.From the height of Yangsi temple construction,the number of population in Ming and Qing dynasties,the predecessors analyzed the large-scale climate of Ming and Qing dynasties from the perspective of phenology and combined with the analysis chart of drought and flood index,the average height of the research area was over 55 meters,the average altitude of the research area was over 55 meters,and the effective altitude was over 55 meters.This thesis analyzes the climate change in the lower reaches of the Yuan River during six historical periods,supplemented by historical documents and statistical tables of historical population changes.The distribution maps of droughts and floods in four counties in the study area are mainly derived from the records of natural disasters in Changde.The ancient river course at the ancient water temple site is more than 40 meters high,indicating abundant water potential,frequent floods,warm or cold damp climate.There are several reasons why the water level in the ancient river is below 40 meters: first,the terrain is gentle,the lake area is small,the water level is low,and second,the water volume is small,the river may dry up and disappear in the future.The weather is dry and cold.