Heavy rainfall maps in Brazil to 5 year return period

Abstract

This study created thematic heavy rainfall maps for Brazil, with durations of 5-, 30-, 60- and 120 minutes and 5 years of return period (T). The intensity-duration-frequency (IDF) relationships used were compiled from studies found in the literature (798 locations) and derived for 4411 rainfall gauges available in the Hidroweb information system, totaling 5209 rainfall data collected. To derive IDF relationships, Gumbel's probability distributions were used, with parameters estimated by the method of moments. Distribution adequacy was verified by the Kolmogorov-Smirnov test. Rainfall-intensity values obtained by IDF relationships were spatialized in Geographic Information Systems, allowing elaboration of the thematic maps. Thematic maps enable obtain rainfall intensities for places without rain gauge data and/or precarious time-series data. Therefore, these maps are a great tool for the design of hydraulic structures related to urban and rural micro-drainage.

Assessing intensity-duration-frequency equations and spatialization techniques across the Grande River Basin in the state of Bahia, Brazil

“…Next, the quantiles associated with the return periods of 2, 5, 10, 20, 25, 50 and 100 years were estimated from the Gumbel quantile function. Then, the daily rainfall amounts, for each return period, were desegregated with the method suggested by the Departamento de Águas e Energia Elétrica (1980), which, despite lacking a rigorous mathematical background, has been extensively utilized in many similar studies (Aragão et al, 2013;Moreira et al, 2020;Souza et al, 2019), with acceptable errors with respect to the intensities derived from-pluviographic data in many regions in Brazil (Abreu et al, 2022;Dorneles et al, 2019). The disaggregation coefficients are presented in Table 1.…”

“…Using uninterrupted records of rainfall data from rain gauges is the most usual alternative to estimate an IDF relationships (Souza et al, 2019). However, in many regions of the world there is a reduced number of pluviograph information, which hinders the probabilistic modeling of extreme rainfall at sub daily time scale.…”

“…The use of geostatistical tools for spatialization of extreme rainfall quantiles constitutes an alternative for regions with scarcity of rain gauges. In these cases, the interpolation of quantiles associated to pre-established durations frequently used for hydraulic design may provide predictions of the quantities of interest (Souza et al, 2019). The main techniques for this purpose are the Inverse Distance Weighting (IDW) and the Ordinary Kriging (Pizarro et al, 2018;Rabelo et al, 2018;Souza et al, 2019), the former being based on a deterministic approach whereas the latter stems from the theory of geostatistics (Ly et al, 2013).…”

Transformação da máxima precipitação diária para estabelecimento de equações de chuvas intensas: nova proposta

“…As chuvas intensas são caracterizadas por apresentarem elevado volume precipitado em curto espaço de tempo (ARAGÃO et al, 2013;CAMPOS et al, 2017); como uma exemplo, chuvas acima de 30mm em 10 minutos produzem intensidades de 180mm/h, típico de muitas regiões do sudeste. Estas chuvas podem exercer consideráveis impactos negativos, tais como prejuízo para a produção agrícola, erosão hídrica, inundação de cidades, e assoreamento de baixadas e leitos de rios, dentre outros (MENDES et al, 2019;SOUZA et al, 2019;SPENCER et al, 2015;SPLINTER et al, 2014). Além disso, a frequência de ocorrência desses eventos de chuvas intensas é importante para a segurança urbana e de obras hidro-agrícolas.…”