Research on the Construction Mechanism and Ecological Wisdoms of Dike-Polder Settlements in Jianghan Plain:A Case Study Based on the Tianmen-Qianjiang-Mianyang Area

WAN Zhiyuan; LIU Mengxin; PAN Yingzi

doi:10.3969/j.issn.1000-0232.2025.07.006

Abstract：The Jianghan Plain,which evolved from the ancient Yunmeng Marsh,serves as Central China's granary.Its dike-polder settlements represent a unique form developed over two millennia of human-water conflict.This study systematically analyzes the spatial patterns,construction mechanisms,and ecological wisdoms of these settlements in the Tianmen-Qianjiang-Mianyang region.From the perspective of"preparedness in times of peace",traditional disaster-response ecological wisdoms were extracted from these dike-polder settlements for contemporary application.This holds significant warning and referential value for ensuring the health of the human habitat in Jianghan Plain,enhancing its disaster resilience,and safeguarding national territorial space,grain production,and the safety of people's lives and property. This study summarizes settlement evolution mechanisms across macro,meso and micro scales.At the macro scale,settlement contours were intelligently extracted using the AI Earth platform with a 5-pixel filtering threshold.A spatial overlay analysis of ZY-3 satellite remote sensing images and a digital elevation model(DEM)was carried out using ArcGIS.At the meso and micro scales,field surveys and spatial mapping were conducted of typical settlements like Gaoqiao Village and Qiwuling Village in Wangchang Town,Tianmen City,and Yufanfeng Village in Xiantao City.Their disaster response wisdoms were summarized by integrating terrain elevation data,water system distribution and prehistoric archaeological site data. Three spatial patterns were revealed macroscopically: (1)Hill-Basin settlements,distributed in the northern low hills of Tianmen(elevation 35～50 meters,10.82％),form a vertical disaster-prevention pattern of"dwellings on ridges-fields in valleys-ponds for water storage"based on the natural ridges. (2)Dike-Platform settlements,concentrated along the Han River plains(69.73％),situated as linear developments on artificially constructed platforms about 4m high,with dike crests significantly higher than historical flood levels.This achieves the dual function of habitation safety and proximity to farmland. (3)Grid-Platform settlements in the southwestern lowlands(15.36％)formed the"kilometer-grid"patterned settlements(about 2m high)based on the water conservancy projects from the 1950～1960s.They form comprehensive waterlogging-resistant corridors by integrating roads,ditches,settlement buildings and polder fields.These three types of settlements reflect the environmental adaptive gradient from hills to lowlands through their construction modes. A four-phase construction mechanism was refined from meso-scale and micro-scale investigations: (1)"Pond digging and platform building":Earthwork balance was achieved by vertically digging 2m-deep ponds and building platforms,forming an integrated pond-platform-polder field structure. (2)"Platform connection into dikes":Driven by clan proliferation(seven major surnames in Qiwuling Village),platforms were extended eastward and westward to form settlement clusters through great efforts over a century; (3)"Encircling dikes into polders":A multi-level water system(main canal → branch canal → paddy field)was built by enclosing farmland with primary and secondary dikes for simultaneous irrigation and drainage. (4)"Fishing,wood cutting,farming,and studyin":Ecological cycles were deepened.The pond system of"fish farming → silt fertilizing mulberry trees →mulberries feeding fish"was applied to support the fishing industry.Platform trees offered building materials of"catalpa wood for beams"and firewood.The ditch network of polders guaranteed farming,while peaceful living and study were realized through the elevated schools,ultimately embodying the ecological philosophy of"humanity-nature harmony". These mechanisms embody three core ecological wisdoms.(1)In terms of vertical adaptation,the elevation sequence(Hill-Basin＞Dike-Platform＞Han River water level＞Grid-Platform)progressively mitigates flood risk.(2)For resource cycling,the pond system forms a closed material flow,achieving sustainable yields of"double benefits and tenfold crop yields".(3)In facility intensification,platforms act as a"trifunctional"(production-living-ecology)carrier that integrates buildings,roads,drying yards,irrigation ditches,and shelterbelts,thus enhancing land efficiency significantly. Major water conservancy projects like the Three Gorges Dam and Jingjiang Levee have shielded the Jianghan Plain from flood disasters for nearly 50 years.However,this study shows they have also led to a diminishing awareness of disaster preparedness in human habitat planning and construction within the plain.It is urgent to revive the preparedness wisdom of"deepening ponds and elevating platforms"and strengthen the Jianghan Plain's disaster resilience to safeguard national territorial space,grain production,and people's lives and property.