Equações de chuvas intensas para sete localidades do Estado de Mato Grosso

Abstract

The knowledge of observed data of outflow is important for elaboration of projects of hydraulical workmanships such as spillways of dams, channels, terraces, agricultural drainage, among others. One of the paths to discover the project outflow, when there is no historical data outflow, is to make an intense rain study. Considering the scarcity of information concerning the events of outflow and / or intense rainfall in the Mato Grosso State, it was objectified with this work to determine the equation intensity-duration-frequency for seven meteorological stations in the Mato Grosso State using the methodologies of pluviograms analysis, daily rain disaggregation and Bell’s Method, as well as comparing the estimates of rainfall intensity by applying the equations obtained from these three methodologies. We used rainfall data from seven meteorological stations of that State belonging to the hydrometeorological network of the National Institute of Meteorology (INMET). The stations included in this study are: Cáceres, Canarana, Cuiabá, Poxoréu, Rondonópolis, São José do Rio Claro e Santo Antônio do Leverger. For each station the intense rain equation was gotten using the methodologies previously mentioned. The historical series of average maximum precipitation intensities, corresponding to the different durations were submitted to statistical analysis to identify the probabilistic model that best fit the data presented, this identification being performed using the adherence test KolmogorovSmirnov test at significance of 5%. The adjusted parameters of the equations intensityduration-frequency (K, b, c) showed high variability from station to station showing the importance of determining these equations diverse localities. The methodologies of daily rain Disaggregation and Bell have provided different results from those found by the methodology of analysis pluviograms with ERM overall 25.72% and 44.33% respectively. None of the alternative methodologies (Disaggregation and Bell) used for determination of the average maximum precipitation intensity was better for all the localities, being the methodology of Disaggregation better in four (Canarana, Cuiabá, Poxoréu and São Jose do Rio Claro) of the seven stations studies and the method of Bell best in three (Cáceres, Rondonópolis and Santo Antonio do Leverger).