Research On The Yellow River South Inundated Area And The Formation And Evolution Of Jialu River In The Ming And Qing Dynasties

Since the Ming and Qing Dynasties,the Huanghuai Rivers system has been repeatedly impacted by the flooding of the Yellow River,and the original rivers have gradually become abandoned.During this period,in the eastern margin of the Eastern Henan Plain,Zhengzhou Jialu River was formed in the Yellow River turbulence.Influenced by the geological evolution of Zhengzhou,the Yellow River tends to swing southward,scouring the Guangwu Mountains for many times,resulting in the change of mountain topography,and eventually leading to the south flow of the Yellow River in Zhengzhou area,and scouring out many southward flow channels,one of which is a deep channel scoured by the Yellow River sluice,which becomes the foundation of the Jialu River.After dredging by Liu-Daxia in 1494,a new river,the Jialu River has formed,which connects the north and south of the Huanghuai Plains.At the end of Chenghua period,Li-Zeng dredged the Shuangji River into the Jialu River.In 1529,Xushui River in southwestern Zhengzhou was dredged into the Jialu River as the upstream water source.After the Jiajing period,the overflow of the Yellow River gradually merged into one trough,and the upper source of the Jialu River was cut off from the Yellow River.It became an independent tributary of the Ying River which from the mountains and rivers as the water source recorded in the local chronicles of the Qing Dynasty.After the formation of the Jialu River,the water environment has changed gradually.Before the Jiaqing period,there was abundant water in the rivers and lakes in the Jialu River Basin,while after the Jiaqing period,the drought in the Jialu River Basin intensified and the rivers and lakes dried up and silted up.In this paper,the causes of water environment changes in the Jialu River are analyzed.It is believed that the large-scale and long-term flooding of the Yellow River in the late Qing Dynasty is the main reason for the gradual drought of the water environment of the Jialu River,and that the drought trend of the water environment of the Jialu River is facilitated by man-made harnessing of the Yellow River and the Jialu River.During the Ming and Qing Dynasties,people excavated ditches in the Jialu River Basin,discharged the lakes water and dispersed the runoff of the main river of the Jialu River,which also aggravated the sediment deposition in the basin and accelerated the depletion of the water source of the Jialu River.In the late Qing Dynasty,the increased clogging time of the Yellow River crevasse directly resulted in the increase of flooding time of the Jialu River Basin,causing in the increase of sediment deposition in the Jialu River Basin.Finally,the inadequate dredged of the Jialu River,which could not be eliminated in time,also accelerated the decline of the Jialu River.