| 摘要: |
| 通过历史记录对清代四川省水灾逐年分等定级，以此研究清代四川水灾的时空变化特征。同时，基于信息扩散理论计算出受灾风险概率。结果表明：（1）清代（1644—1911年）共发生水灾1409县次，1861—1890年为水患高发期，1825年后水灾强度显著上升。10 a尺度下水灾强度存在三次高峰，30 a尺度下清末期水灾强度持续增强。前期水灾周期为中长期振荡，1825年后水灾强度显著提高且以中短（8—15 a）周期性振荡为主。（2）水灾密集区主要位于山地-平原交界处的成都府、眉州、雅州府东部区域，受灾指数基尼系数为0.4615，水患平均中心位移较小。（3）全川受灾风险概率在受灾比为0.05—0.15时迅速下降，同等受灾比（0.2以下时）下，川东道受灾风险概率最高；而受灾比高于0.2时，川北道受灾风险最高。（4）东亚季风增强、人口暴露度增加、政治经济动荡造成的社会韧性下降和生态破坏可能是清末四川省水灾强度提高和规模扩大的重要原因。 |
| 关键词: 清代水灾 时空特征 受灾风险 四川省 |
| DOI：10.7515/JEE242001 |
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| 基金项目:四川省社会科学重点研究基地区域文化研究中心年度项目（CQYYJC2101）；国家级大学生创新创业训练计划项目（201910638025，202110638013） |
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| The spatiotemporal characteristics of f loods and the risk measurement of flood proportion in Sichuan during the Qing Dynasty |
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YIN Zhaoqi, LI Weipeng, CHEN Zhongsheng, XIONG Mei, WANG Xiujuan
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1. School of Geographical Sciences, China West Normal University, Nanchong 637000, China
2. Sichuan Provincial Engineering Laboratory of Monitoring and Control for Soil Erosion on Dry Valleys, China West Normal University, Nanchong 637000, China
3. School of History & Culture, China West Normal University, Nanchong 637000, China
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| Abstract: |
| Background, aim, and scope The intensity of global climate change has escalated considerably in the last century, paralleled by an increase in floods in Sichuan. Historically, floods have been among the most prevalent natural disasters in Sichuan. Most previous studies on historical floods in Sichuan are regional scales, focusing on statistical analysis of disaster frequency. However, this approach can fall short in representing the broad impact of floods on the entire province. Consequently, there is a pressing need for a more comprehensive quantitative analysis of historical flood disasters in Sichuan from a broader perspective. In this study, the floods in the Sichuan Province during the Qing Dynasty were reconstructed using historical records, and the patterns and causes of these floods were analyzed statistically, in an effort to contribute to contemporary flood management strategies. Materials and methods Historical records were utilized to quantify and categorize the flood-affected counties in Sichuan during the Qing Dynasty. The probability of disaster was calculated using information diffusion theory. Results (1) Between AD 1644 and 1911, a total of 1409 floods were recorded, with the years from 1861 to 1890 marking a high-frequency period. The intensity of floods exhibited three peaks on a decadal scale, while on a 30-year scale, the intensity progressively increased towards the end of the Qing Dynasty. Initially characterized by medium to long-term oscillations, the flood cycles shifted after 1825 to predominantly medium to short-term oscillations (8—15 years). (2) The regions most susceptible to flooding were primarily located in the eastern sections of Chengdu Fu, Mei Zhou, and Yazhou Fu, situated at the mountain-plains transition zones, with a Gini coefficient of 0.4615. Nevertheless, the average displacement of the disaster center remained relatively stable. (3) The probability of disaster risk throughout Sichuan Province showed a rapid decline when the disaster ratio ranged between 0.05 and 0.15. Based on the same disaster ratio (below 0.2), eastern Sichuan had the highest probability of disaster; when the disaster ratio exceeded 0.2, the risk was greatest in Chuanbei Dao. Discussion (1) Validation of conclusion: the results detailing the sequence of flood intensities in Sichuan during the Qing Dynasty presented in this study align with several other research findings, yet there are discrepancies in pinpointing the exact peak years of flooding. Regarding the geographical distribution of floods, our findings generally concur with most established research; however, slight variations are observed in certain localities. These discrepancies may stem from differences in the raw data utilized, varying criteria for flood selection, and distinct flood grading standards. (2) Analysis of flood factors: concerning global historical climate conditions, temperatures were notably lower during the Little Ice Age, spanning the Ming and Qing dynasties. At the local level in Sichuan, soil freezing can diminish water absorption by the soil and escalate runoff, thereby creating conditions conducive to flooding; additionally, frost damage leads to reduced crop yields, diminishing the community’s resilience against disasters. Based on the precipitation indicator function of δ18O, the northeastern part of Sichuan exhibited increased wetness during the Qing Dynasty, correlating with heightened flood intensity in this area. Thus, there appears to be a link between the increased flood activity in the mid to late Qing Dynasty and regional precipitation patterns in northeastern Sichuan. Furthermore, the population-to-land ratio in Sichuan Province progressively worsened throughout the Qing Dynasty, with settlement distribution expanding and the demand for property intensifying, thereby increasing vulnerability to flooding. Factors such as irresponsible logging and severe soil erosion also contributed to an environment prone to flooding. Collectively, the intensification of the East Asian monsoons, increased population, reduced social resilience due to political and economic instability, and ecological degradation were likely significant contributors to the escalation in flood damage and flood frequency in Sichuan Province during the late Qing Dynasty. Conclusions The variation in the number of flood-affected counties is linked not only to overarching climate and environmental changes but also to the dynamics between people and land, as well as the government’s commitment to disaster relief. Recommendations and Perspectives Given the variegated nature of historical documents, the reconstruction of historical disasters requires an interdisciplinary approach that integrates an array of different data sources. It is crucial to standardize data collection methods and employ new technologies to improve the process of reconstructing and studying historical disasters. Such efforts can provide vital support and guidance in the prediction and management of natural disasters such as floods. |
| Key words: floods in Qing Dynasty temporal and spatial characteristics disaster risk Sichuan Province |
