Abstract
In different regions of Brazil, floods have increased dramatically, affecting millions of people and inflicting huge economical damage. Flood hazard maps are important to integrate geospatial and temporal data in a same computational environment that allows risk assessment, modeling and decision support. This paper discusses different levels of integration approaches between GIS and hydrological models and presents a case study , in which all the tasks of creating model input, editing data, running the model, and displaying output results are available withina GIS. The study area corresponds to the upper section of the Paraíba do Sul basin (Sao Paulo State portion), comprising nearly 15,300 km2 and situated in the Southeast of Brazil. Paraiba do Sul basin has a large importance in the history, culture and economy of Brazil with high urbanization and industrial activities along a part of the main river. The case study presented in this paper has a database which is suitable for the basin dimension including digitized topographic maps. From ArcGIS®/ArcHydro Data Model a geometric network called HydroNetwork was created to produce different raster maps. This first grid derived from the digital elevation model grid (DEM) is the flow direction map followed by flow accumulation, stream and catchment maps. The next steps in this research are to incorporate rainfall time series data from about forty stations to build a hydrologic data model within a GIS environment and to combine ArcGIS®/ArcHydro and HEC-HMS model, in order to produce a spatial-temporal model for floodplain analysis at a regional scale.
Keywords: Geographic Information Systems (GIS); Hydrologic Models; Flood Inundation Model; Paraiba do Sul River Basin