River Basins


River Basins - How is region structured - topography, soils, landuse, climate, flow regime?

     The states of Espírito Santo and Minas Gerais are located in southeastern Brazil, within the Atlantic Forest biome. The biome is considered one of the five most important biodiversity hotspots in the world for conservation due to its exceptional level of species diversity and its vulnerability to continuing threats. The southeastern regions of Brazil forms the most important center of economic and social development of the country; 61% of the economic wealth and 44% of the population are concentrated here (IBGE, 1990).

     As a result of the National Water Resources Policy enacted in 1997, states were given a major role in administering water management, and determining the policy arena in which the river basins will operate. The state of Espírito Santo is currently developing a sophisticated Decision Support System (DSS) that would enable scenario analyses for decisions on the resources of Espírito Santo by centralizing a resource base and developing predictive scenarios and appropriate interventions, with climatic and ecosystem changes in mind, through PCGAP.

     To relate an individual site to the attributes of its region, it is useful to think of  “scaling” – to zoom from a broad region to a site, and back again, recognizing the trade-offs in data and information that have to be made to do this. Not all instruments and data sources see something the same way, pending what the original purposes of the observer were. It can be useful to compare several different sources, to work towards the most unbiased solution. For PCGAP, the focus is currently on two scales of interest, and will expand to three, at progressively higher degrees of resolution. The first is the state of Espírito Santo, using the VIC model. For the state-wide application, a major decision was made to include the entire Rio Doce in the model setup. This was done because it makes little sense, hydrologically-speaking, to model “only” the lower basin, in just Espírito Santo. The second scale of interest is to zoom in to the basins of the Rio Jucu and the Rio Santa Maria da Vitória, as the primary scale of focus for FpV. Zooming in still further will be a focus on the basin of the Rio Mangaraí (of particular interest to CESAN. The DHSVM model is used for these finer scale applications.

     The development of the data frame describes how each model resolution requires specific data compilation of topography, soils, landuse, and climate.