Agresividad de las precipitaciones en la subcuenca del río San Marcos, Puebla, México

Lacks of information on the erosive nature of rain in Puebla's Northern Sierra have not allowed an objective evaluation on its contribution to the overall erosive process. The following study had as objective to determine the erosive potential and temporal variability of precipitation in the San Marcos river sub-basin through different índices that measure the degree of aggressiveness of rainfall, as well as to establish correlations between these Índices. Precipitation values registered during a ten year period, encompassing seven meteorological stations, were used. The following indices were calculated: yearly Fournier Index (fi), Modified Fournier Index (mfi), Precipitation Concentration Index (pci), and Erosion Index (ei). The study allow to conclude that the risks of erosion are greater in the influence zone of the climatic stations of Xicotepec, Venustiano Carranza, and Progreso, found in altitudes between 1 279 and 886 m.a.s.l. Rainfall, in accordance to the PCI, concentrates in a moderate seasonal manner between the months of july and october, and the EI shows that the rainfall presents a high erosive potential. Results would support the development of an agro-ecological strategy for the conservation of soil in accordance to the aggressiveness of the climate in the zone of study.