Susceptibility to Flooding of Urban Areas Puerto Vallarta - Mexico Julio Cesar Morales Hernández 1 , Oscar Frausto Martinez 2* , Bartolo Cruz Romero 3 , Jorge Ignacio Chavoya Gama 4 , Fátima Maciel Carrillo González 3 1 Centro de Estudios Meteorológicos de la Costa, Departamento de Ciencias Exactas, Centro Universitario de la Costa, Universidad de Guadalajara, Av. Juárez No. 976, Colonia Centro, Guadalajara 44100, Jalisco, Mexico 2 Laboratorio de Observación e Investigación Espacial, Universidad Autónoma del Estado de Quintana Roo; Avenida Andrés Quintana Roo, S/N, Frente a colonia San Gervasio, Cozumel 77600, Quintana Roo, Mexico 3 Departamento de Ciencias Exactas, Centro Universitario de la Costa, Universidad de Guadalajara, Av. Juárez No. 976, Colonia Centro, Guadalajara 44100, Jalisco, Mexico 4 División de Ingenierías, Departamento de Ciencias Exactas, Centro Universitario de la Costa, Universidad de Guadalajara, Av. Juárez No. 976, Colonia Centro, Guadalajara 44100, Jalisco, Mexico Corresponding Author Email: ofrausto@uqroo.edu.mx https://doi.org/10.18280/ijdne.170305 ABSTRACT Received: 18 March 2022 Accepted: 6 June 2022 The Mexican Pacific coast is frequently affected by meteorological systems that cause rain. These events are beneficial when they precipitate in the internal valleys of the basins and water is captured from the highlands by filtration, recharging the aquifers, and allowing surface runoff through rivers and runoffs that are the natural sources of freshwater. On the other hand, these systems are adverse when they precipitate in excess, and additionally, they are associated with bad decisions and urban planning errors that put at risk the life and patrimony of some social sectors, this aspect has become a national security issue for the authorities. The region of Bahia de Banderas has a rainwater drainage network through open-pit channels that partially cover the urban area, a situation that puts the population and its assets at risk since rain considered common causes significant puddles, a situation that is progressively worsening, but the great danger of an extraordinary amount of rain, as has occurred in the past, is represented by the hydrological basins that cross or are adjacent to it, an aspect that will be discussed in greater detail in this article. Keywords: watersheds, vulnerability, Jalisco, extreme precipitation 1. INTRODUCTION Due to its location and geographical characteristics, Mexico is exposed to the occurrence of hydro-meteorological phenomena, mainly tropical cyclones, river and coastal flooding, intense winds, cold and heat waves, snowfalls, hailstorms, etc. [1]. Related to these phenomena are also severe local storms of high intensity and short duration that cause floods and landslides. On the other hand, there are regions of the country that are affected by water shortages for prolonged periods, causing floods and landslides. Other regions are affected by winter systems. These weather phenomena that cause rain, on the one hand, are adverse when excessive and are associated with human error, but, on the other hand, bring benefits, since it is the only source of freshwater. Mexico has many hydrological basins, due to the rugged relief; these are of great importance because they capture the water that rains, an aspect that has gradually become a matter of national security. In the region, the accelerated growth of Puerto Vallarta and its surroundings, including nearby towns in the south of Nayarit, exceeded by far the expectations of having a storm drainage network, a situation that is currently suffered because the rainfall considered common, causes significant puddles, a situation that is gradually accentuated, with more notable rains. With more heavy rains, called copious, rivers and streams overflow, recurrently affecting certain neighborhoods with the loss or damage of household goods, but with the occurrence of a severe local storm defined by the amount of rainfall, or a so- called torrential rain, the effects it would cause in urban areas that are gradually growing in vulnerability, would be disastrous. In Puerto Vallarta, there is also a latent potential risk that implies the danger of extraordinary flash floods, an experience with which the current generations are not familiar, because the return period is very long, that is to say, it has not occurred in the last decades. The urban area has an adjacent hydrological basin (exoreic) and others that cross certain neighborhoods, also exoreic but geographically known as watersheds, since, starting from a watershed. It is to say that the highest limit that divides the fall of rainwater between two adjacent and opposite slopes, but which finally discharge their waters individually into the sea, of course, another aspect of risk is that part of the urban area is located precisely at the mouth of these basins (Figure 1). There is also interest in society to carry out the change of land use and build new settlements with a criterion of high added value and, under a series of unfounded arguments, these settlements may be in risk areas, ignoring Civil Protection reports. which will undoubtedly cause disasters and will be blamed on climate change. International Journal of Design & Nature and Ecodynamics Vol. 17, No. 3, June, 2022, pp. 359-367 Journal homepage: http://iieta.org/journals/ijdne 359