Modelagem de escoamento acoplado de superfície e subsuperfície em encostas naturais no Vale Aburrá (Medellín, Colômbia)

Numerical results are presented of surface-subsurface water modeling of a natural hillslope located in the Aburrá Valley, in the city of Medellín (Antioquia, Colombia). The integrated finite-element hydrogeological simulator HydroGeoSphere is used to conduct transient variably saturated simulations. The objective is to analyze pore-water pressure and saturation variation at shallow depths, as well as volumes of water infiltrated in the porous medium. These aspects are important in the region of study, which is highly affected by soil movements, especially during the high-rain seasons that occur twice a year. The modeling exercise considers rainfall events that occurred between October and December 2014 and a hillslope that is currently monitored because of soil instability problems. Simulation results show that rainfall temporal variability, mesh resolution, coupling length, and the conceptual model chosen to represent the heterogeneous soil, have a noticeable influence on results, particularly for high rainfall intensities. Results also indicate that surface-subsurface coupled modeling is required to avoid unrealistic increase in hydraulic heads when high rainfall intensities cause top-down saturation of soil. This work is a first effort towards fostering hydrogeological modeling expertise that may support the development of monitoring systems and early landslide warning in a country where the rainy season is often the cause of hydrogeological tragedies associated with landslides, mud flow or debris flow. © 2016 Springer-Verlag Berlin Heidelber

A new and highly effective sampling plan using attractant-baited traps for the coffee berry borer (Hypothenemus hampei)

Several sampling plans have been developed for many insect pest species. However, few sampling plans have been based on attractant-baited traps. The coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae: Scolytinae) is a key coffee pest of worldwide importance whose sampling plans usually demand the harvest and inspection of up to 5,000 coffee berries per field, which is labor-intensive, costly, and ineffective. Therefore, this system constitutes a good model for the development of a more cost-effective sampling plan based on attractant-baited traps for capturing adult insects allowing the sustainable management of this pest species. The reported study was performed in 27 coffee fields using berry damage-assessment techniques and capture of adult borers applying attractant-baited traps made of PET-bottles (polyethylene terephthalate bottles). The relationship between trap capture and berry damage was significant allowing the use of the former to estimate coffee loss caused by the borer. The trap capture data from the coffee fields were adjusted to a negative binomial distribution suitable for establishing a single conventional sampling plan for all investigated fields. The required trap density varied from 14 to 355 traps/10 ha, depending on the precision error selected. The sampling plan developed using spatial interpolation (kriging and inverse weighted-distance methods) indicated that using 22 traps/10 ha for sampling of the coffee berry borer, costing US$ 303.24/10 ha and requiring 49.14 min/10 ha for the sampling procedure, was suitable and resulted in cheaper, faster, and more reliable estimates compared to present recommendations