What is MGB

The MGB hydrological model is a distributed model developed for applications in large basins.

For us, large-scale hydrology is the study of large watersheds. And large hydrographic basins, in our view, roughly fit the following criteria (not definitive):

– Regions generally larger than 1000 km²;

– Regions where the river propagation processes cannot be neglected, that is, that the travel time of water in the drainage network is long (high concentration time) and that the processes of translation and attenuation of flood waves are relevant in the understanding of the dynamics of the basin.

– Regions where the difference between surface and groundwater dividers can be overlooked;

– Regions where rain and other characteristics such as type and use of soil cannot be considered homogeneous throughout the area, and for this reason the classic hydrology methods are not adequate;

– Regions where terrain characterization is difficult to do with purely in-situ measurements, requiring the support of GIS and remote sensing techniques.

MGB has been developed at the Hydraulic Research Institute (IPH) of the Federal University of Rio Grande do Sul (UFRGS) over the past 10 years.

The MGB uses data on precipitation, air temperature, relative humidity, wind speed, insolation and atmospheric pressure to calculate river flows in a hydrographic basin.

In the original version, the MGB model used a way of dividing the watershed area into regular units (cells). In the current version, the hydrographic basin is divided into small sub-basins, called mini-basins, using the techniques of the ArcHydro tool set, as shown in the following image:

Summary of MGB functioning.

Resumo dTo facilitate the use of the model, an IPH team developed interfaces for the program within the MapWindow GIS and Quantum GIS software, which are freely available GIS software. The interface facilitates the generation of input data for the model, has data analysis and post-processing tools and allows an integration of the model with the potential of the GIS.

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