Traditional Water Conservancy And Environment On The Southern Edge Of The Tengger Desert For Nearly Three Hundred Years

The topic attempts to examine the relationship between traditional water conservancy and the environment on the southern edge of Tengger Desert in the past three hundred years.The construction of the traditional water conservancy on the southern edge of Tengger Desert took place after the military activity took back the territory near the Song mountain during the Wanli period of the Ming Dynasty.After the Ming Dynasty government expelled the Mongolian tribes that lived there in 1599,a series of fortresses have been established between the southern edge of the Tengger Desert and the Wushaoling veins,and each of them has its own traditional water system.Most of the fortresses and local traditional water conservancy existed on the edge of the desert about 300 years,creating a good living environment.It experienced the transition in the mid-Qing period when bastions were changed to ordinary villages and towns gradually,and also faced the impact of modern water conservancy technology after 1942.So,these fortresses(specifically Yongtaibao and Dajingbao)was selected as research objects to examine the relationship between local traditional water conservancy and the environment.The Palmer Drought Severity Index(PDSI)made by geologists and the local description in the literature confirm that the drought conditions in the southern edge of the Tengger Desert in the past 300 years have not changed much.It has been a relatively dry situation.The relationship between local traditional water and environmental changes and climate fluctuations is not obvious.The Yongtai bastion is located in Yongtai Village,Jingtai County,Gansu Province now.Its shape is same as a tortoise.It was built in the reservoir named Daqingchi at the beginning of the construction of the city,which to facilitate its breeding.In the Qing Yongzheng period,Yue Zhongqi built the water system called Wuzangliufu integrated with the open channel and hidden channel,which is similar to the Karez in Xinjiang.In addition,locals also use barrage to bring a seasonal river to the higher fields.Relying on traditional water conservancy systems,local agriculture and social culture are relatively good.After the Qianlong era(1736-1796),they transformed into ordinary villages and towns gradually.Commercial prosperity happend at there supported a large number of people,moreover in 1940 there was planned to be a demonstration area.However,after 1969,the construction of modern irrigation areas began,and local residents either actively or passively moved to relatively modern irrigation areas.With the loss of population,local traditional water resources have been destroyed and the desertification in there was rapidly severe.The Dajing bastion is located in Dajing Town,Gulang County,Gansu Province.Its traditional water conservancy during the Ming and Qing Dynasties inncluded Changling Ba(Ba means one irriagtian area in this area),Shanquan Ba.,and Dahe Ba,and Jiaochang Ba which was groundwater irrigation area.What happened at Dajing is different form the previous description of the Hexi basic water conservancy,such as poor conducted or technical backwardness,from researches using the water case as the main material.Dajing's traditional water conservancy according to the characteristics of the Dajing River flowing from Dajing valley,it will divided into three irrigation areas,watering in batches.In addition,the local traditional water conservancy will continue to be optimized,and the irrigation period will be changed according to its actual irrigation effect.In 1942,the government of the Republic of China introduced the Ten-Year Plan for mordern water conservancy in Hexi Corridor.Modern technologies were introduced into the Dajing area.But traditional water conservancy has not been abandoned.The local water conservancy system still uses the old Dajing Three Ba and Jiaochang Ba,and uses modern water conservancy technology to optimize traditional water conservancy facilities.But after the construction of the modern irrigation district in 1984,Dajing traditional water conservancy was confined to a very small extent.By studying Yongtaibao.we can see that traditional water conservancy created a stable settlement on the edge of the desert from the Ming Dynasty,but it quickly declined at the end of the 20th century.The general view is that the expansion of desertification has caused the settlement of Yongtai to decline.However,according to the study,the author found that the loss of the population caused the neglect of local water conservation.The decline of water conservancy caused the desertification in there.This is the tragedy of"retreating from desert".In addition,take Dajing as an example,the local traditional water conservancy is not as poor as previous studies described.They have their own stability and continuity,and after 1942,modern water conservancy was very successful in the optimization and transformation of traditional water conservancy.However,at the end of the 20th century,the traditional water conservancy was confined into the little area by the modern irrigation district,though it still has vitality.According to the relationship between the traditional water conservancy and the environment at Yongtai and Dajing in the past 300 years,for mitigating desertification,traditional water conservancy and traditional towns based on traditional irrigation works play an important role in the local area.