Chan, Ba Dihydrate Historical Changes

The Chan River and the Ba River are the most important two rivers in the east of Xi'an city. They have been providing water for eastern Xi'an from the ancient time to the current time and playing important roles. Both the Chan River and the Ba River originate from the Lantian County. The Ba River is the first tributary of the Wei River, and the Chan River is the first tributary of the Ba River. The Chan River runs into the Ba River in Baqiao district of the Xi'an city and then flows about ten kilometers into the Wei River to the north. With the historical development of the Xi'an city, the Chan River and the Ba River also have their own vicissitudes.The vicissitudes of the Chan River and the Ba River are mainly reflected in the aspects of channels, water amount, water quality, wetland and so on. The upper stream channels of the Chan River and the Ba River vary little, and the changes are mainly in the midstream and the downstream areas. The changes in the midstreams of the Chan River and the Ba River are mainly the channel's westward movement which is caused by the raise of the Lishan Mountain and the Hengling plateau, and the changes in the downstream of the two rivers are the raise of the channels by silt sediment. The water amount of the Chan River and the Ba River differs with the changes of the environment in different times, but the overall trend is gradual reduction. With the social development and the destroy of the environment by human beings, the sediment concentration increases. There are few records about the wetland of the Chan River and the Ba River, but we can see its situation in the Yuan Dynasty. The Anxi Palace of the Yuan dynasty lies in the wetland area of the Chan River and the Ba River. According to historical literatures, the environment around the Anxi Palace is very beautiful and there are rich plants and water, showing a typical wetland landscape.Except their own vicissitudes of the Chan River and the Ba River, we can also analyze the artificial projects related to the two rivers to make research on the visages of the Chan River and the Ba River in the history so as to know their situations from the side. The vicissitudes of the Longshou Channel, the Cao Channel and the Guangyun Pool reflect the changes of the water amount and the sediment concentration of the Chan River and the Ba River.After entering into the modern times, our country begins to take the protection of the environment seriously through "pollution first, and improvement second" experience of the West, and the river improvement is an important way. Now, the Xi'an city has authorized the construction of the Chan Ba ecotope priorities, which takes great improvement to the Chan River and the Ba River and the ecological environment around them. They are confronted with unprecedented good opportunities.Through the research on the vicissitudes of the Chan River and the Ba River, we can see that natural factors dominated the changes of the river in the early time of the human society, and the influence of the human beings is little. With the progress of humanity, the anthropogenic factors gradually become the dominant reasons of the environmental vicissitudes. Only developing harmoniously with the nature, can it be conducive to we human beings'survival.