Joint Probability Analysis of Extreme Precipitation and Storm Tide in a Coastal City under Changing Environment

Abstract

Catastrophic flooding resulting from extreme meteorological events has occurred more frequently and drawn great attention in recent years in China. In coastal areas, extreme precipitation and storm tide are both inducing factors of flooding and therefore their joint probability would be critical to determine the flooding risk. The impact of storm tide or changing environment on flooding is ignored or underestimated in the design of drainage systems of today in coastal areas in China. This paper investigates the joint probability of extreme precipitation and storm tide and its change using copula-based models in Fuzhou City. The change point at the year of 1984 detected by Mann-Kendall and Pettitt’s tests divides the extreme precipitation series into two subsequences. For each subsequence the probability of the joint behavior of extreme precipitation and storm tide is estimated by the optimal copula. Results show that the joint probability has increased by more than 300% on average after 1984 (α = 0.05). The design joint return period (RP) of extreme precipitation and storm tide is estimated to propose a design standard for future flooding preparedness. For a combination of extreme precipitation and storm tide, the design joint RP has become smaller than before. It implies that flooding would happen more often after 1984, which corresponds with the observation. The study would facilitate understanding the change of flood risk and proposing the adaption measures for coastal areas under a changing environment.

Staged Optimization Design for Updating Urban Drainage Systems in a City of China

“…The flood disasters cause huge socio-economic losses and seriously affect the activities of residents. For example, the 2005 flood event brought by Typhoon Longwang resulted in over 120,000 people evacuated and 62 dead [4].…”

“…The flood disasters cause huge socio-economic losses and seriously affect the activities of residents. For example, the 2005 flood event brought by Typhoon Longwang resulted in over 120,000 people evacuated and 62 dead [4]. There are two common ways to resolve flooding in cities: (1) Traditional methods, such as enlarging pipe sizes and upgrading pumping capacity and (2) low impact development (LID) approaches, such as the construction of green infrastructure.…”

“…Only in 2012, many mega-cities such as Beijing, Shanghai, Wuhan, Guangzhou, Shenzhen, Chongqing and Nanjing, experienced serious flooding, particularly the July 2012 flood disaster in Beijing City killing 79 people and causing the loss of at least 10 billion Yuan [4,7,8]. From 2008 to 2010, 62 percent of 351 cities surveyed in China suffered flooding events, and among them 137 cities experienced flooding three times according to the statistics released by China's government [4,9].…”

Joint distribution of design precipitation and tide and impact of sampling in a coastal area

“…() and Xu et al . () used the Gumbel–Hougaard copula to compute the joint distribution of precipitation and storm tide in Fuzhou city in eastern China. Zheng et al .…”

“…However, few studies have focused on the joint distribution of design flood and tide or design precipitation and tide. Lian et al (2013) and Xu et al (2014) used the Gumbel-Hougaard copula to compute the joint distribution of precipitation and storm tide in Fuzhou city in eastern China. Zheng et al (2013) employed a bivariate logistic threshold-excess model to conduct the dependence of extreme precipitation and storm surge on the Australian coastline.…”