A paleo-hydro-geomorphological perspective on urban flood risk assessment

Link O.; Brox-Escudero L.M.; González J.; Aguayo M.; Torrejón F.; Montalva G.; Eguibar-Galán M.Á.


Comprehensive flood risk assessment requires enhanced understanding of the coevolution of the river and its floodplain occupation. Paleoflood analysis to determine flood prone areas in combination with numerical simulations to estimate flood hazard and a historical analysis of urban development to consider the evolution of exposure to floods is a possible way forward. The well-documented 2006 extreme flood in the Biobio River system and the impacted metropolitan area of Concepcion, Chile (similar to 1 million inhabitants) was used as a complex scenario to test the reliability of the proposed method. Results showed that flood prone areas determined with hydro-geomorphological methods are consistent with those computed with numerical models based on detailed digital elevation models. The flood generation via superficial flow pathways resulting in inundated areas could explain that rivers tend to reactivate paleochannels in extreme conditions. Urban development progressively increased the city's exposure to floods from 0 ha in 1,751 to 1,363 ha in 2006 evidencing a lack of appropriate flood risk management. The 100-year peak discharge resulted in a high flood risk for about 5% of the total urbanized area of Concepcion, and higher discharges are likely to reactivate a paleochannel that crosses the current city centre. We conclude that the proposed paleo hydro-geomorphology, hydraulic, and urban planning multimethod approach is a necessary tool to enhance understanding of flood risk in complex scenarios to improve flood risk management.

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Título según WOS: A paleo-hydro-geomorphological perspective on urban flood risk assessment
Título según SCOPUS: A paleo-hydro-geomorphological perspective on urban flood risk assessment
Volumen: 33
Número: 25
Editorial: Wiley
Fecha de publicación: 2019
Página de inicio: 3169
Página final: 3183
Idioma: English