Spatiotemporal Characteristics and Decision-Making Mechanisms of Flood-Induced City Relocations:A Case Study Based on Cities along the Ming-Qing Old Course of the Yellow River

ZHANG Xuenan; ZHOU Ling

doi:10.3969/j.issn.1000-0232.2025.10.006

Abstract：Flooding became frequent after the Yellow River captured the Huai River's course.These floods,carrying large amounts of sediment,often caused devastating damage to surrounding cities.Water would remain lodged within city walls for extended periods,and the silt deposited after the water receded would bury cities underground,forcing many of them to relocate.A case study based on the areas along the Ming-Qing old course of the Yellow River was carried out.A total of 24 cities within a 35-km-wide buffer zone(extending 35 kilometers on either side of the old course)were used to examine the spatiotemporal characteristics and decision-making mechanisms of flood-avoidance relocation. First,the historical information was interpreted using the ArcGIS platform from a long-term and holistic perspective.The spatiotemporal distribution of these relocation activities was explored and visualized through a quantitative analysis of five dimensions,including timing,frequency,direction,distance,and place attributes.The results reveal several significant patterns in these five dimensions of flood-avoidance relocation along the old course.First,for chronology and frequency,flood-avoidance relocation was most common during the Ming dynasty.Relocation on the south bank occurred earlier than that on the north bank,and relocation activities were more frequent along the river section upstream from Xuzhou.Furthermore,the relocation frequency of prefectures was significantly lower than that of sub-prefectures and counties.Second,for direction and distance,the relocations were predominantly unilateral without crossing to the opposite bank,with an obvious tendency for reciprocal and short-distance moves.The Shandong-Henan section was a concentrated area for short-distance relocation.Additionally,the relocation distance increased significantly during the Qing dynasty.Finally,for place attributes,hill-type sites appeared later and were concentrated in the area near Xuzhou,whereas city gate-type sites were clustered along the river section upstream of Xuzhou.Meanwhile,old city and market town sites were distributed across the entire region throughout the period. Subsequently,a"constraints-trade-offs"analytical framework was constructed to investigate the decision-making mechanisms behind these relocation activities.This framework emphasizes the need to recognize both the force of objective environmental constraints and the importance of subjective trade-off choices made under these constraints,thereby excavating the urban development wisdom embedded in flood-avoidance relocation practices.On the one hand,decision-making for city relocation was constrained by geographical,political,technical,and economic factors;these factors included the distribution and siltation processes of lakes,the terrain,river management policies,hydraulic engineering construction,administrative divisions and the overall administrative framework,and relocation costs.As a result,decisions followed certain overarching patterns,reflecting a passive adaptation to the environment.On the other hand,individual cities made trade-offs to seek the most suitable paths for flood-avoidance development within the limited available spaces determined by environment,using four proactive strategies:(1)conforming to the terrain and occupying higher ground;(2)prioritizing locational advantage and moving toward commercial hubs;(3)holistically managing resources to reduce costs and burdens;and(4)integrating city construction with water management through a system of encircling dikes.Thus,seemingly individualized relocation activities reflect a profound understanding of the living environment and urban development that people have formed over long periods of struggling with flood disasters. Against the contemporary background of protecting,inheriting,and promoting Yellow River culture and the regional policy of constructing an ecological corridor along the Ming-Qing old course of the Yellow River,this study makes the following key contributions.(1)It helps deepen the understanding of the water-management-centered settlement culture of historical cities along the old course,thus shedding light on important cultural attributes of this area.(2)It uses statistical analysis to promote recognition of historical city site resources along the course,and deepen the understanding of historical continuity in the region.(3)It excavates systematic and dynamic perspectives contained in historical city relocation decision-making,which can provide wisdom for contemporary planning for sustainable urban development.