广州城市暴雨内涝时空演变及建设用地扩张的影响

暴雨内涝是城市常见的“城市病”。本研究通过收集20世纪80年代、90年代,以及2000年之后广州市主城区严重暴雨内涝资料,探索改革开放后广州市暴雨内涝时空演变特征,分析城市建设用地扩张对暴雨内涝的影响。结果表明,20世纪80年代至今,广州市主城区暴雨内涝点在时间和空间2个尺度上有显著的变化。早期内涝点主要集中于市中心的越秀区,随着城市化进程的推进逐渐在白云、天河等城市化较快的区域出现。从1990-2010年,广州市城乡建设用地扩张显著,城市不透水面密度与暴雨内涝点核密度呈正相关。其相关性随城市化发展逐渐增强,表明改革开放后广州市城市的快速扩张,对主城区暴雨内涝点的时空演变有较大的影响。因此,城市暴雨内涝的防治应重视城市不透水面格局的优化和调整。

Spatio-temporal Characteristics of Urban Storm Waterlogging in Guangzhou and the Impact of Urban Growth

Urban storm waterlogging has become one of the common serious “urban diseases” in China. The purpose of this study is to examine the spatio-temporal characteristics of urban storm waterlogging in Guangzhou from the 1980s and analyze the relationship of urban storm waterlogging and urban growth. Information about the urban storm waterlogging in Guangzhou was gathered from the newspaper of Guangzhou Daily and from the waterlogging census implemented by Guangzhou Bereau of Water affairs. Moreover, Landsat TM/ETM 30 m images for the years of 1990, 1999, and 2010 were collected to monitor the urban growth of Guangzhou. Density estimation method was used to quantify the density of these waterlogging spots and calculate the construction land ratio of Guangzhou. The relationship of urban storm waterlogging with urban growth was explored using Pearson correlation coefficient. The results show that the urban storm waterlogging spots in Guangzhou had increased greatly on the time scale and had sprawled since the 1980s on the spatial scale. In the 1980s, waterlogging disaster mostly took place in Yuexiu district, which is the core area of Guangzhou. However, the disaster had gradually spread into districts that having rapid urban growth such as Baiyun and Tianhe after the 1990s. Simultaneously, the urban area also had sprawled rapidly from 1990 to 1999 and to 2010. According to the results of Pearson correlation coefficient calculation, the density of waterlogging spots is positively correlated with the construction land ratio, and the correlation relationship gradually strengthens with respect to the rapid urbanization, implying the notable impact of construction land ration on urban storm waterlogging. The results suggest that more attention should be paid to the optimization of construction land ratio in urban planning procedure, and the government should improve the condition of drainage pipeline system and facilities to avoid urban storm waterlogging.