Determinação das equações de chuvas intensas em bacias hidrográficas do Rio Grande do Sul

• Autor(a) principal: Sampaio, Marcela Vilar
• Data de Publicação: 2011
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Manancial - Repositório Digital da UFSM
• Texto Completo: http://repositorio.ufsm.br/handle/1/3593
• topic: Curvas IDF; Métodos de desagregação; Precipitações extremas; Heavy rain, disaggregation, watersheds; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA

The design of hydraulic structures to curb the excessive rain, dams, containment basins, terraces, and others are designed with a rainfall that can define the maximum flow of the construction project, satisfying the desired security and is a project economically rational. The lack of precipitation stations with long historical series (20 years) has led to designers from those used in hydraulic relationships that enable the estimation of rain from the project using data from rain gauge stations with greater availability and longer historical series. This study aimed to establish the relationship between intensity, duration and frequency of maximum rainfall in catchment areas of Rio Grande do Sul, from the breakdown of rain 24 hours in duration and aimed at verifying the adherence of the rainfall data theoretical models of probability distribution, to compare different methods of disaggregation of heavy rainfall with durations less than 24 hours and to analyze the variability of the coefficients of the equations of rainfall of different basins of the state. The performance of different methods of disaggregation (Bell, Pfafstetter, Chen, Hernandez and CETESB) employed in the estimation of maximum rainfall for durations shorter than 24 hours with the use of historical series of rainfall stations in watersheds of the RS were compared with values of relations durations obtained in a study by Beltrame et al (1991) on rainfall in the RS. Performance evaluation of different models of breakdown was performed using the coefficient Willmot that allows the analysis of deviations between the estimated values and those obtained by the relationship of duration with adjusted data pluviograms and thereby indicate the methodology which shows better performance. The results allowed the determination of the equations of rainfall for basins of RS by an alternative approach to traditional methodology which presents great difficulties, due to the scarcity of rain gauge records, the difficulties in its production, the low density of the network and pluviographs the short observation period available combined with a thorough job of tabulating, analyzing and interpreting a large amount of rainfalls.