Análisis de susceptibilidad por crecidas excepcionales basado en herramientas SIG.

Abstract

The El Guayabal micro-basin, belonging to the Mocotíes river basin, has been affected in different events such as 1.994, 1.999, 2.005, 2.011, 2.012 and 2.014, being the most dramatic the one of 2.005 which brought about mass removal processes; product of the lack of protection of the soil as a result of the agricultural activity (prevailing in the micro-basin) as well as the flood and overflow of the El Guayabal drainage, mainly due to the configuration of the valley bottom, which due to its narrowness favors the processes of damming and overflow Causing material losses and human lives. For this reason, an analysis of the susceptibility to floods was carried out, emphasizing the conditioning variables of the event, such as geology, geomorphology, soil type, slope, land use and vegetation cover, without leaving One side is the importance of the drainage with respect to its flow. The variables were superimposed to deduce the potential impact of an adverse event. Taking into account that the Multicriteria Assessment (EMC) methodology was applied, which generated a scenario in the area where the assigned weight for each variable was highlighted that the results are not encouraging for the population that there it lives (1,440 inhabitants) as well as for the natural resources of the environment, given that they are of moderate, high and very high susceptibility, knowing in turn the percentage that each level occupies within the microbasin as well as its area; This information could not be corroborated in the field but according to the information of the thematic layers of each variable, it is deduced that this is the approximation to reality, concluding that the methodology is efficient because it presents results appropriate to the environment. Depending on the unfavorable conditions of the study area, it is necessary that the local authorities with competence in the field of risk management focus on implementing plans for preparing the community for this type of event, in the same way that works of prevention and correction of torrents such is the case of: dykes for the retention of sediments and channeling to avoid the lateral scour of the slopes which contribute sediments to the water tributary without leaving aside the processes that occur internally in these that affect roads and the drains; causing alteration in fluvial dynamics. Finally, the results of the EMC were contrasted with the behavior of the basin through the estimation of morphometric parameters, which showed that it is a torrential micro basin with high sediment carryover capacity, as well as a moderate concentration time that could allow it to run an early warning system in the area, but that this be quick and effective what is achieved with practice is to say the insertion of the culture of risk in the communities that live there; otherwise, its implementation would be ineffective and impossible.