Modelling the impact of land subsidence on urban pluvial flooding: A case study of downtown Shanghai, China

Abstract

This paper presents a numerical analysis of pluvial flooding to evaluate the impact of land subsidence on flood risks in urban contexts using a hydraulic model (FloodMap-HydroInundation2D). The pluvial flood event of August 2011 in Shanghai, China is used for model calibration and simulation. Evolving patterns of inundation (area and depth)are assessed over four time periods (1991, 1996, 2001 and 2011) for the downtown area, given local changes in topography and rates of land subsidence of up to 27 mm/yr. The results show that land subsidence can lead to non-linear response of flood characteristics. However, the impact on flood depths is generally minor (< 5cm) and limited to areas with lowest-lying topographies because of relatively uniform patterns of subsidence and micro-topographic variations at the local scale. Nonetheless, the modelling approach tested here may be applied to other cities where there are more marked rates of subsidence and/or greater heterogeneity in the depressed urban surface. In these cases, any identified hot-spots of subsidence and focusing of pluvial flooding may be targeted for adaptation interventions.

Measuring Spatiotemporal Features of Land Subsidence, Groundwater Drawdown, and Compressible Layer Thickness in Beijing Plain, China

“…In most areas worldwide, compressible sediments are the material basis and it unbalances the starting point of land subsidence; groundwater drawdown is an inherent drive and its spatial diversity induces an uneven development process of land subsidence [3][4][5][6][7][8][9][10][11]. Land subsidence has increased the risk of other disasters and threatened the properties of the society [12][13][14][15]. Mapping and quantifying how, and to what extent, the groundwater drawdown and compressible layer influence non-uniform land subsidence based on multiple time-series displacement and hydrogeological data are of concern to many scholars [16][17][18][19][20].…”

Assessing the vulnerability of pumping stations to trash blockage in coastal mega-cities of developing nations

“…Pluvial flooding occurs during intense rainfall as a result of surface water runoff associated with low permeability in urban areas that may be lying above and far from coastal and river floodplains (Douglas et al, 2010). Considering that pluvial floods are normally only a few centimetres deep, pumps are not often used to mitigate such type of floods (Yin et al, 2016). Coastal flooding is associated with high 4 tides / waves, storm surges and sea-level rise that result in overtopping or breaching of coastal defences and the consequent inundation of areas lying on the coast of the sea or ocean (Wolf, 2008).…”

An integrated framework for high-resolution urban flood modelling considering multiple information sources and urban features

“…As a result, greater flood impacts to human society are expected to happen (Curebal et al, 2016;Korichi et al, 2016;Rosso and Rulli, 2002). For example, the July 2012 flood event in Beijing led to 79 deaths and an estimated economic loss of US$1.86 ×10 9 (Yin et al, 2016a). To develop effective strategies for flood risk management, better understanding of flood dynamics is essential.…”