More frequent flooding? Changes in flood frequency in the Pearl River basin, China, since 1951 and over the past 1000 years
Qiang Zhang1,2,3, Xihui Gu4*, Vijay P. Singh5, Peijun Shi1,2,3, and Peng Sun6 1Key Laboratory of Environmental Change and Natural Disaster, Ministry of Education, Beijing Normal University, Beijing 100875, China
2State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China
3Faculty of Geographical Science, Academy of Disaster Reduction and Emergency Management, Beijing Normal University, Beijing 100875, China
4Department of Atmospheric Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
5Department of Biological and Agricultural Engineering and Zachry Department of Civil Engineering, Texas A&M University, College Station, Texas, USA
6College of Territory Resources and Tourism, Anhui Normal University, Anhui 241000, China
Abstract. Flood risks across the Pearl River basin, China, were evaluated using a peak flood flow dataset covering a period of 1951–2014 from 78 stations and historical flood records of the past 1000 years. The generalized extreme value (GEV) model and the kernel estimation method were used to evaluate frequencies and risks of hazardous flood events. Results indicated that (1) no abrupt changes or significant trends could be detected in peak flood flow series at most of the stations, and only 16 out of 78 stations exhibited significant peak flood flow changes with change points around 1990. Peak flood flow in the West River basin increased and significant increasing trends were identified during 1981–2010; decreasing peak flood flow was found in coastal regions and significant trends were observed during 1951–2014 and 1966–2014. (2) The largest three flood events were found to cluster in both space and time. Generally, basin-scale flood hazards can be expected in the West and North River basins. (3) The occurrence rate of floods increased in the middle Pearl River basin but decreased in the lower Pearl River basin. However, hazardous flood events were observed in the middle and lower Pearl River basin, and this is particularly true for the past 100 years. However, precipitation extremes were subject to moderate variations and human activities, such as building of levees, channelization of river systems, and rapid urbanization; these were the factors behind the amplification of floods in the middle and lower Pearl River basin, posing serious challenges for developing measures of mitigation of flood hazards in the lower Pearl River basin, particularly the Pearl River Delta (PRD) region. Published in Hydrology and Earth System Sciences, 2018, 22: 2637-3653, https://doi.org/10.5194/hess-22-2637-2018, 2018Citation: Zhang, Q., Gu, X., Singh, V. P., Shi, P., and Sun, P.: More frequent flooding? Changes in flood frequency in the Pearl River basin, China, since 1951 and over the past 1000 years, Hydrol. Earth Syst. Sci., 22, 2637-2653, https://doi.org/10.5194/hess-22-2637-2018, 2018.
