The evaluation of the meteorological drought is fundamental for the management of the water resource. One of the most used indices to evaluate the drought is the standardized precipitation index (SPI) due to its practicality and evaluation in a variety of time scales, however, this uses precipitation as the only variable, depending on the deviations in the precipitation values. This is important when evaluating the SPI, because in some ecosystems close to the equatorial zone, there are very warm periods with low rainfall, in which a large proportion of the data collected by the meteorological stations corresponds to zero. In this research, the SPI was calculated in the Pechelín basin located in Colombia, in which there is zero precipitation in a large proportion of the data, registering zero precipitation in the month of January and February in 67% and 70% respectively. As a result, the SPI values increased to “wet” ranges, only when the amount of data with zero precipitation exceeded half of the total data; this means that the SPI determines wrong values when it is calculated with zero-precipitation data in large proportions. Based on this finding, this study aims to modify the index by typing the distribution (using a correction factor K), finally correcting the SPI values, this correction was called SPI-C. The results indicate that the SPI-C improved the identification of drought, obtaining corresponding values that better represent the high frequency of zero precipitation existing in the study area.

Tropical hydrographic basins have undergone significant land use change processes in recent decades and correspond to areas of high population growth and development of economic activities. This article explores the causes of land use change in a tropical dry forest watershed, taking the Canalete river basin as a case study. For this purpose, stakeholder analysis techniques and participatory methods were applied. The results showed that the main causes of land use change in pastures were associated with biophysical factors, while forestsshrubs and crops were associated with direct and subyacents socioeconomics factors respectively. The participatory mapping allowed obtaining a desired land use scenario for the year 2030, observing a decrease of more than 16.2 ha of pasture, compensated by an increase of almost 2.4 thousand ha of crops and 13.8 thousand ha of forests and shrubs. Similarly, the hydrological impact of changes in land use was observed, especially in terms of flooding.

24 revista de ingeniería. Universidad de los Andes. rev.ing.

Contexto: Los fenómenos erosivos en las playas del Caribe colombiano tienen repercusiones negativas sobre la población, razón por la cual se decidió evaluar diferentes propuestas de estructuras para la protección costera. Se realizó un análisis comparativo entre arrecifes artificiales y estructuras flotantes mediante modelación CFD para condiciones típicas del Caribe colombiano con el objetivo de establecer cuál estructura presenta mejor comportamiento. Métodos: Se utilizó el software Flow3D para evaluar cinco estructuras básicas sumergidas, configuraciones grupales de éstas y una placa flotante, en dos profundidades de lámina de agua y dos escenarios de altura de ola. Resultados: Se estableció el efecto de la profundidad y de la geometría en el flujo para las estructuras básicas y las grupales, así como los campos de velocidad y esfuerzos cortantes presentes en éstas. Para la estructura flotante sólo se analizó el efecto de la profundidad. Conclusiones: Se encontró que las estructuras que presentan el mejor comportamiento son el prisma triangular para las básicas y el grupo de cubos para las grupales. La estructura cónica es aquella con el peor comportamiento para ambas condiciones. La estructura flotante funciona mejor cuando está más cerca de la superficie y, para la misma profundidad, la configuración grupal de cubos tiene un mejor comportamiento que la estructura flotante.