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 band widths 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, in accordance with IBER's ACA Standard, which showed that more 80% of the area of the flood envelope is in very high danger.