Assessing urban flood and drought risks under climate change, China

Abstract

Risk analysis of urban flood and drought can provide useful guidance for urban rainwater management. Based on an analysis of urban climate characteristics in 2,264 Chinese cities from 1958 to 2017, this study evaluated urban flood and drought risks. The results demonstrated that the annual average values of precipitation, aridity index, frequency and intensity of extreme precipitation and extreme drought events differed significantly in these cities. The values of the above six climatic indicators in the cities ranged from 9.29–2639.30 mm, 0.47–54.73, 1.08–8.79 time, 7.82–107.25 mm, 0.76–2.99 time, and 10.30–131.19 days, respectively. The geographical patterns of urban precipitation, aridity index, intensity and frequency of extreme precipitation and drought events in China fit well to the Hu‐Huanyong Line that was created in 1940s to identify the pattern of population distribution. Extreme precipitation in most cities has upward trends, except for those around the Hu‐Huanyong Line. The extreme drought events had upward trends in the cities east of the Hu‐Huanyong Line, but there were downward trends in the cities west of the line. The risk assessment indicated that 3.80% cities were facing serious flood and 6.01% cities were facing serious drought risks, which are located in the coast of southern China and northwestern China, respectively, and other 90.19% cities were facing different types of drought and flood risks in terms of their intensity and frequency.

Addressing Challenges of Urban Water Management in Chinese Sponge Cities via Nature-Based Solutions

“…In the 2018 National State of the Environment Report, more than 74% of cities were identified as having a poor groundwater quality status [43]. Currently, urban drainage standards are mostly 1-in-1 to 1-in-5 year return period storms, which is insufficient to cope with rising urban flood risk [44]. In July 2020 alone, more than 20 million people were affected by floods, across many cities in 24 Provinces [45].…”

Protecting health in dry cities: considerations for policy makers

“…Reduced water availability results from reduced rainfall in regions that are already dry. Rising temperatures increase evaporative loss of surface water and reduce summertime flow in snowmelt fed rivers 152728293031. Additionally, dry weather can be punctuated by sudden heavy rainfall, a well recognized phenomenon in arid regions 3233…”

Trends and variability in flood magnitude under climate change in the Qilian Mountains, Northwest China

“…IPCC (2021) shows that climate change is already an undeniable phenomenon, and that the occurrence of extreme flood events is also associated with rising temperatures, heavy precipitation and an accelerated hydrological cycle at global and regional scales (Bloeschl et al, 2019, Bloschl et al, 2017, Kundzewicz et al, 2019a.Catastrophic floods, primarily associated with climate change, have also attracted public attention and have been the focus of much research (Alfieri et al, 2017, Cornwall, 2021, Nigel et al, 2014, Wilby &Keenan, 2012. Many recent flooding events around the world have led to growing concern that flood disasters are becoming more frequent and severe along with flooding events (Kundzewicz et al, 2019a, Kundzewicz et al, 2019b, Liang et al, 2019, Tezuka et al, 2014.…”