Danger from flooding during Hurricane Stan in the Vicente Guerrero River basin, Siltepec, Chiapas, Mexico

Abstract

Hurricane Stan (October 3 to 6, 2005) affected the Vicente Guerrero River basin, Siltepec, Chiapas, Mexico, socially, economically, hydrologically, and hydraulically. On October 5, 2005, the maximum precipitation of 552 mm/day fell. Through hydrological modeling, with the HEC-HMS model, a peak flow of 460.1 m³/s at the outlet of the basin and the hydrographs at the exit in each sub-basin were obtained. These data were used in hydraulic modeling with the IBER model, which reported maximum levels of 5.75 m and maximum speeds of 11.38 m/s in the channel. Flood bandwidths of 100 m were generated on both banks. The results were validated with the information of a Bing Maps satellite image of December 2005, observed at the passage of the hurricane, comparing the coordinates, X, Y, and Z, of the simulated event against the observed event, achieving r² = 0.99 for each margin. With this information, a "hazard map" was generated, by IBER's ACA Standard, which showed that more than 80 % of the area of the flood envelope is in very high danger.