A Risk-Based Approach for the Analysis of Flood Impact in Villahermosa (Tabasco, Mexico)

Abstract

Floods in Villahermosa are events that have occurred frequently over the centuries, due to the city’s location at the mouth of two of the most powerful rivers in Mexico. Flooding effects on residents have become increasingly damaging over the years as a consequence of the increase in frequency and intensity of extreme weather phenomena, in addition to poor land-use planning policies. The increase in population and consequent urban expansion are certainly causes of the problem, which are reflected in poor urban planning policy and in an almost absent perception of risk. In this work, we present a methodology for the construction of flood risk maps based on a hydraulic study, analysis of social vulnerability indexes, calculation of severity indexes and construction of hazard maps. The results of the hydraulic simulations show that relatively frequent rainfall causes floods of the order of 2 m, in agreement with annual observations conducted in Villahermosa. More extreme rainfall can lead to flooding greater than 4 m in marginalized areas of the city. The areas at greatest risk are sections close to the rivers that cross the city, and the estimated economic damage is greater than USD 14 million. Risk maps presented here constitute the first effort of an integrated study to couple flood analysis with the calculation of economic damage in the city of Villahermosa, and provide important tools to conscientize populations in their perception of risk, but also create the basis for a conscious urbanization policy.