Evolution Characteristics of Bottomland in Dongting Lake Since the Middle of the Republic of China
In order to study the temporal and spatial evolution characteristics of bottomland in Dongting Lake since the middle of the Republic of China,this paper used the historical maps and aerospace remote sensing data of 15 periods since the middle of the Republic of China,used remote sensing interpretation and historical comparison methods to study subzone of bottomland development in modem Dongting Lake.The evolution characteristics and change reasons of main bottomland from 1938 to 2021 were analyzed.The results showed that the bottomland of Dongting Lake was dominated by terrigenous detritus,accompanied by biogenic sedimentation.The sedimentary types included lacustrine deposits,river alluvial deposits,floodplain and river delta deposits,and river lake interactive deposits.Furthermore,different sediment characteristics were displayed due to the different water and sediment conditions in different seasons.The modern bottomland of Dongting Lake was divided into 20 sub regions,including 9 sub regions in the east of Dongting Lake,8 sub regions in the south of Dongting Lake,and 3 sub regions in the west of Dongting Lake.In the East Dongting Lake,Piaowei Island was the largest beach of Dongting Lake,with an area of 466.89 km2 during dry seasons.The estuary delta of the east branch of the Ouchi River was the fastest growing bottomland in the last century,which was located at the junction of Zhuzi bleeder in 1938,and estuary delta had extended 12.13 km2 eastward to the current shoreline,and then the river channel advanced 26.42 km2 toward the lake.The bottomland of South Dongting Lake mainly developed along the Songzhu River and the north of Wanzi Lake.The Xiangjiang River floodplain,the ancient Xiangjiang River and the Zishui Delta were eroded and silted,but their outlines were clear in dry seasons.In West Dongting Lake,Qili Lake had become a component of Songli floodway due to sedimentation,and the northern part of Muping Lake was the Songli Delta,while the southern part was the Yuanshui Delta.The sediment was severely silted up,and the main lakes were basically dried up during dry seasons.The research results provided objective data for the rational development and utilization of Dongting Lake bottomland resources and the adjustment of the Dongting Lake region's lake management strategy in the post-Three Gorges era.
middle of the Republic of Chinahistorical mapremote sensing technologyDongting Lake areabottomland subzonebottomland evolution
NETL
NSTL
万方数据
