¿SON ACEPTABLES EN LA COSTA DE CHIAPAS, MÉXICO, LAS TORMENTAS SINTÉTICAS DEL SCS DE 24 Y 6 HORAS DE DURACIÓN?

Abstract

Taking into account that important hydraulic structures are designed with hypothetical storms of 6 or 24 hours durations, in this research it was reviewed the time distribution of several rainfall events in the Coast of Chiapas in Mexico, especially those of duration of 24 and 6 hours and some of smaller duration. The reference pattern was that of the U. S. Service Conservation Soil (SCS) synthetic design storm type III for coastal areas. The data was obtained for year 2011, from April to November, and for October 2005, when occurred Stan Hurricane; the storms were distributed through 6 study sites instrumented with pluviographs. The Nash-Sutcliffe coefficient and the Relative error were the statistical parameters used as comparative criteria. In the case of 24-hours rainfall duration, their Nash-Sutcliffe coefficients presented values between 0.46; 0.89 and Relatives Error between 3.8 and 17 % and Standard Error between 9.26 and 17.37 %. In the case of the 6-hours rainfall duration only a 50 % of the events presented a good fit with Nash-Sutcliffe coefficients between 0.3 and 0.98; Relative Errors between 0.3 and 9.1 % and Standard Error between 3.71 and 16.40 % and when there was no good fit, the SCS intensity 6-hours duration values were below the real storm intensity values. Also it was found that the hyetographs for durations less than 6 hours presented a triangular distribution.