鄱阳湖流域城市洪涝灾害风险及土地类型调整策略研究——以景德镇市为例

Analysis of Urban Flood Disaster Risk in the Poyang Lake Basin and Land Type Adjustment Strategy Study——A Case Study of Jingdezhen City

在全球气候变化和人类活动影响下,流域内城市洪涝灾害发生的频率、强度及其造成的损失日益加剧,更好的揭示洪涝灾害风险的时空演变规律对不同流域下城市防灾减灾具有重要意义。基于流域城市洪涝灾害风险的形成过程,从致灾因子、孕灾环境、承灾体、防灾减灾能力4个方面选取指标,构建了基于格网的流域城市小尺度洪涝灾害风险评价模型,并以景德镇市城区为例,将空间风险定量计算,分析了城市洪涝风险的时空分异特征,最后提出土地利用类型的调整策略。结果表明:从空间上,城区洪涝灾害风险极大值与极小值差值存在较大的差异,呈现由昌江、南河、西河等河流为中心向四周逐渐减小的方向性变化,不同区域的风险波动性幅度不同,社会经济发展水平较高的珠山区昌江沿岸区域为景德镇城区的洪涝灾害高风险区,西部、西南部山区以及东部乡镇由于地势较高,风险水平较低。从时间上,景德镇市城区的洪涝灾害风险最大值呈下降趋势,南部洪涝灾害风险整体变小,但风险集中程度不断加剧,城区西部风险值有小幅度的上升;针对不同的区域特征,通过两种方案对城区内洪涝灾害易涝典型地区进行土地利用类型调整,两个区域风险分别从0. 606与0. 610降低到0. 561与0. 571。

Due to the influence of global climate change and severe human activities,the frequency and intensity of urban flood disasters in basin are increasing frequently. Because of various urban development of cities in the Poyanghu Basin,the land use structure was forced to change. Because of the rapid urban development in Poyanghu Basin,the land use structure changes continuously. Meanwhile,some unreasonable land use type increased the risk of flood disaster. It ’s significant and necessary to study and reveal the spatial-temporal distribution of the flood risk in the different basin. The study can be used as a support tool to help local stakeholders make future flood risk prevention and reduction planning,and flood disaster management. In this study,the urban region of Jingdezhen City in Poyanghu Basin was selected as the study area. Firstly,the formation of flood risk and the causes of flood disasters in cities of basin were analyzed. Secondly,based on the formation process of urban flood risk in Basin,the assessment index was set up from four main aspects( disastercausing factors,disaster-pregnant environment,disaster-bearing body and the prevention and mitigation ability).Thirdly,a small-scale flood disaster risk assessment model was developed based on Analytic Hierarchy Process( AHP) and Geographic Information System( GIS). Finally,taking the urban area of Jingdezhen as a case,the spatial risk was calculated quantitatively. And the adjustment strategies of land use type in the typical flood disaster affected areas were put forward according to the spatial-temporal distribution of flood disaster risk. The results showed that there was a big difference between the maximum and minimum values of flood disaster risk in urban areas from the perspective of space. The risk decreased gradually from the center line of Urban River to the surrounding. The range of risk volatility in different regions was different. The Changjiang coastal area of Zhushan District which has high social and economic development level were the high-risk areas and the risk level was low in western,southwest and eastern towns. From the perspective of time,the maximum value of flood disaster risk in the urban city decreased from 2010 to 2013 while the local areas of high flood disaster risk were more concentred. The risk of flood disaster in the South became smaller as a whole. The value of flood disaster risk in the western part of the city increased slightly. According to the different regional characteristics,two hypothetical adjustments were adopted to change the land use types in the typical flood areas in the basin. After calculating the average value of flood disaster risk,the value of flood disaster risk in two regions decreased from 0. 606 and0. 610 to 0. 561( 7. 4%) and 0. 571( 6. 4%) respectively.