Avaliação dos efeitos da disponibilidade espacial e temporal dos dados hidrológicos sobre a calibração de um modelo distribuído na bacia do rio Ipanema

Abstract

The development of models for simulating and predicting the effects from the binomial rainfall-runoff has been improved by the scientific community and used as a reliable tool for operating cost low compared to other available technologies. The various applications of the models and their indications for specific regions with parameters of use, focused on the study area, close acceptably model, the natural behavior of the basin and serve as a starting point in the study of basins with similar conditions. Studies involving mathematical models applied hydrology in Brazil have focused their attention on watersheds, reservoirs and rivers in the south and southeast of the country, in the semiarid northeast, due in part by the amount, spatial distribution and quality of data needed to work with models that range of study is fairly small. The challenge of this study dates back to the acquisition and formatting of input data for application calibration and determining the factors that make the application of the model for large basins MGB-IPH feasible in the semiarid northeast, specifically when used in the river basin Ipanema. The study used a distributed model of large basins MGB-IPH; developed by the Institute of Hydraulic Research IPH Rio Grande do Sul. The MGB-IPH model presents interface that gathers information geographical, climatic, soil, vegetation, rainfall and runoff, as well as Fixed calibration parameters and variables. The routines simulate the hydrological processes of soil water balance in small basins, runoff, leachate volume, the upward flow, evapotranspiration and propagation of the small basins volumes. In Ipanema River basin was used satellite images of the region, derived from the Shuttle Radar Topography Mission (SRTM / NASA) with the digital elevation model DEM, then getting the topographic profile necessary for defining the digital terrain model MDE, together with data fluviometric, rainfall and climatological time series of the period between 1977 to 2008. In the calibration of the parameters for the MGB-IPH, the values achieved statistical Nash 0.405 and 0.68 Person data show that the basin proved insufficient to define the calibration values in the model this occurs due to the large area without coverage posts for a large spatial and temporal variability of hydrological processes, which also influences the hydrological analysis of the region. The increase in volume of flow data calculated was mainly the result of the simulated peaks erroneously by the model, thus creating false volumes disposed. Such inconsistencies are the result of large voids in the geographical basin, produced by a lack of jobs data collectors fluviometric, rainfall and climatological maintained by official organizations, highlighted may indicate the North West River Basin Ipanema.