FLOOD RISK DUE TO EXTREME RAINS IN THE KARST OF THE CITY OF MÉRIDA YUCATÁN MEXICO

Abstract

Background. Yearly hurricanes and tropical storms formed in the Atlantic are natural flooding hazards to The Yucatan Peninsula due to unplanned land use changes when new urban areas are to be developed on karstic soils such as in the case of the municipality of Merida. Objective: This work aimed to generate a flood risk map due to extreme meteorological events when storms and hurricane occurred in the municipality of Merida. Methodology: To assess flood risk on a detailed scale, the main input was the digital elevation continuum; it was classified into three classes of elevations: very high risk, less than 4 meters above sea level (m.a.s.l); high from 4 to 7 m.a.s.l.; medium from 7 to 10 m.a.s.l.; and low, greater than 10 m.a.s.l.; the population layer by localities was included in order to estimate the amount of population at risk by type of flood. Results: the areas with high to very high risk of flooding due to tropical storms and hurricanes are located in the north of Merida, where urban areas are in continuous expansion. These results were validated during the recent flood events. Implications: It is recommended that areas with high to very high risk of flooding be declared as eco-archaeological and environmental protected natural areas. Conclusions: In the north of Mérida are located 46 ha with the water table below 7 m from the ground surface so continuous urban growth is not recommended. The flooding risks of this area ranged from high to very high due to the rise of the water table during storms and hurricanes.