Análise da consistência de dados hidrológicos a partir de diferentes modelos digitais de terreno
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2015-02-20
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Universidade Federal de Goiás
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In the digital relief is best represented by the digital terrain model (DTM) and the automatic extraction from topographical parameters of this data type, configures a viable alternative in relation to the manual process performed on topographic maps. However, the available data may contain faults or present information to altitude that are not exactly the terrain. In this sense, it is important to consider these issues in the application of MDT. In hydrology, for example, you must perform preprocessing steps to eliminate inconsistencies that might prevent the natural reproduction of the flow of water toward the riverbeds. The objective of this research is to check the limits of applicability of the MDTs in hydrological analyses. For this, we used 5 (five) MDTs data: Light Detection And Ranging-LIDAR; Aerial Photography; Topodata; ASTER Global Digital Elevation Model-Aster GDEM; Shuttle Radar Topography Mission-SRTM, with different spatial resolutions and methods of acquisition. These data were applied a technique of hydrological correction and subsequently were extracted attributes from all surfaces. This information was used in the construction of the time of concentration and consequently the design hydrographs, which in turn were used to extract the maximum flow of project to return periods of 5, 10, 15, 20, 25, 50 and 100 years, in a range of the curve number (CN) varying between 40 and 99. It was built using a programming language of 60 dimension array rows by 7 columns, where each line represents the maximum values of each design hydrograph flow generated from each value of CN. In the end, it was obtained a set of 24 arrays containing the values of the maximum flows of project for each CN value, and attributes extracted of the MDTs and of digital models of terrain Hidrologicamente Consistent (MDEHCs). In possession of this information, a statistical test was applied in order to assess the influence that the hydrological consistency method and the dimensions of the cells of the MDTs/MDEHCs had about the project flows. Was observed in one of the sub-basins analysed that the difference between the maximum design flow is directly proportional to the increase in CN and payback period. It was noted a difference of up to 173.7 m3/s to a CN of 99 and return period of 100 years. The hypothesis H0 of the proposed test was accepted in all return periods both in relation to hydrological consistency method applied as compared to cell dimension of MDTs. This means that it is possible to affirm with an error probability of "P-value" for return period, which the flows generated from the parameters of the MDTs differ from flows generated from the parameters of MDEHCs as well as between the MDTs surveyed at a significance level of 5%. From the results, it might be concluded that the interpolation method for hydrological consistency and size of the cell of the MDTs has influence on the generation of the maximum flow of project.
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RIBEIRO, H. J. Análise da consistência de dados hidrológicos a partir de diferentes modelos digitais de terreno. 2015. 149 f. Dissertação (Mestrado em Engenharia do Meio Ambiente) - Universidade Federal de Goiás, Goiânia, 2015.