Reconstructing the spatiotemporal distribution of polders in modern Dongting Plain, Hunan Province

Abstract

To better understand the process of land reclamation in the Dongting Plain (DTP), this paper reconstructed the spatiotemporal distribution of polders in the area. The images of polder patches were extracted from Google Earth using visual interpretation, and the corresponding polder names and times of polder construction were extracted from maps and local gazetteers. Moreover, this paper examined the possible relationships between the spatiotemporal distribution of polders and the regional environment change and socio-economic history. The results showed that: (1) The total area occupied by modern polders (in the 2010s) is 9703.18 km2, and the area was constructed in six stages that constituted 5.73% of the modern total area in 1368–1644, 8.29% in 1644–1735, 9.33% in 1736–1850, 31.71% in 1851–1911, 18.51% in 1912–1949, and 26.41% in 1949–1980. (2) In terms of the spatial distribution of polders constructed at each stage, the polders in 1368–1644 were predominately located in the northern DTP, and polders in 1644–1735 and 1736–1850 were predominately located in the south. Owing to the formation of the Ouchi River and the Songzi River, the new polders were constructed along the rivers in the central plain in the last three stages after 1850. (3) Multi-factors played distinctive roles in the construction of polders in different stages. The location affected the initial spatial distribution of polders in the mid-14th century. In the long run, the growth in population contributed to the increase of polders. The Four Rivers mainly affected the spatial distribution of polders in the south part of the DTP before 1850, and the four channels of the Yangtze River mainly affected polders in the north-central part of the DTP after 1850. The polders along the Xiang and Zi Rivers were cumulatively constructed and formed in multiple stages. The polders were constructed in the period from 1368 to 1850, and area accounted for 57.82% of polders along rivers. The polders along the four channels of the Yangtze River were a gradual development with continuous expansion, and the polder area in 1850–1980 was 92.40%.