Fen River Middle Reaches Of Rivers And Lakes, Historical Period Changes

Content:Water is the basis of emergence and development of human civilizations, is the most sensitive and the fragile in natural geographical factors. Rivers and lakes are water carrier, have had frequent and the complex vicissitude in historical period, the change has had the profound influence to the nature and the human geography. Attention to basin, the evolution of basin water environment, the ecology and the social economy system is one of important research contents in historical geography. In historical period, there were numerous lakes and plenty of irrigation water in middle reaches of Fenhe River, to achieve SanJin civilization of irrigation fanning and bred the historical and cultural city like Taiyuan, which become the most important areas of economic and urban concentration. But at the same time, there appeared a series of environmental problems like water shortages, underground water level dropped substantially, the underground funnel area expanded and so on, which become the bottleneck of social and economic sustainable development in Shanxi. To study the change of river and lake in the middle of Fenhe river not only has important academic value, but also has a strong practical significance.The traditional research of river-lake's change mainly depends upon the historical documents to carry on the qualitative analysis and research. The development's trend of modern historical geography requests disciplinary fusion and quantitative research. Environmental change is the geographical processes of long period, some fragment intercepted cannot reflect the complete picture of changes. Therefore, this study extends time interval, which starts from the brand-new world to the modern age. The research of prehistoric period without the literature record mainly relies on strata, archaeological, pollen and fossil of plants and animals etc, to analyze and judge the characteristics of natural elements like climate, vegetation, animals and spatial distribution characteristics of human settlements in middle reaches of Fenhe River, to speculate the change of rivers and lakes. Since pre-Qin, mainly combined historical data with archaeological, ancient map, modern topographic map, remote sensing image data as well as meteorological and hydrological data of device measurement etc, for comprehensive analysis, mutual support, reveal the process, reason and law of rivers and lakes'change in middle reach of Fenhe river. At the same time, adopt the method of modern cartography, the space form of rivers and lakes'change will be showed on topographic maps intuitively.This article takes rivers and lakes'vicissitude in the middle reaches of Fenhe River as the object of study, mainly has done the following job:(1) The prehistoric lakes'change. Through to analyze comprehensively the archeological data mentioned, the prehistoric human settlements are mostly distributed platform or piedmont foothills in Fenhe river and its tributaries, the altitude from 1300m gradually altitude down to about 900m, reflected the vein of vicissitude which human occupies the lakes and they draws back; Since pre-Qin, through the case studies about ZhaoYuQi and WenHu, to find that the nature evolution is primarily before Yuan Dynasty, that the Ming and Qing Dynasties the human activity plays the decisive function on the process of lakes'vicissitude; Meanwhile, the water balance of ancient lakes in the middle reach of Fenhe river is studied by quantitative and multidisciplinary method like geography and hydrology. (2) The rivers'vicissitude. The article conducts the research separately to the main current and the branch. The eight main rivers'change of main current and local typical incident have be argued detailed; The branch selects the Jinwater River and Xiaohe River as the case to analyze, to explore the relevancy between the change and human activities. (3) Selects the factors such as biodiversity, drought and flood disaster and geological disaster, studied the response of watershed ecological environment about the rivers and lakes'vicissitude. (4) From the angle of natural and cultural factors, analyze comprehensively the reason of rivers and lakes'vicissitude, natural factors from climate, geology, topography and vegetation are analyzed; Humanistic factors from the population, the irrigation engineering and settlement are discussed, during Yongzheng and Guangxu, the irrigation water of Xiaohe River is estimated; Sediment deposition under the joint action of each factor is investigated quantitatively.Through the above research, draws following conclusion:(1) The vicissitude of rivers and lakes in middle reach of Fenhe River has undergone lakes'prosperity--coexistence of rivers and lakes--rivers flouring and lakes decay three stages:the Holocene early and mid, human activities are limited, lakes are prosperous; from the pre-Qin to the Yuan dynasty, human activities affect enhancement, fanning and irrigation technology improve gradually, showing that lakes gradually subsidies and rivers increase, which is closely tied to the development of all rivers with high sediment in middle and upper reaches Fenhe river. Since the Ming and Qing dynasties, the humanity reclaim land by surrounding and filling in lake bottom, causing lakes vanish completely, and irrigation requirement increases sharply, making water balance unsustainable.(2)The rivers and lakes are interdependent and closely related, Fenhe and its tributaries supply water for lake, lakes adjust water for rivers. The stable runoff supplies are the decisive factor which the lake lasts, the immediate cause of lake dies is significant changing course of Fenhe river. Low-lying areas after ZhaoYuQi and WenHu lake dying become the flood storage in middle reaches of Fenhe river, Fenhe River and Wenyuhe River's confluence and diverge are the main melody, the river course migration are frequent. (3) Throughout the whole change, natural and humanistic factors play the role together, the earlier period natural factor takes the decision effect, including dominant factor--climate, geological and geomorphic and vegetation factors decide the precipitation, runoff and the silt quantity's change, which has affected the river-lake's hydrological changes. Later period the humanities' function strengthens. The population growth, the settlement vicissitude and the agricultural productive especially the development of irrigation cause the water imbalance of the basin, change the dynamic balance, to a great extent influence the future direction of rivers and lakes.In brief, the relationship between human and basin is important topic in modern historical geography, also is the question we must face for social and economic sustainable development, especially is eternal subject for the humanity to recognize and transform nature.