RESUMO O conhecimento das relações entre intensidade, duração e frequência (relação IDF) das chuvas intensas é de enorme importância para o projeto de obras na Engenharia. No entanto, a disponibilidade desses dados é limitada no Brasil. Dessa forma, com a necessidade de estimar informações nos locais sem dados, o engenheiro Taborga Torrico, em 1974, propôs oito regiões brasileiras com condições microclimáticas homogêneas (isozonas), dentro das quais o comportamento das chuvas intensas é semelhante, sugerindo ainda valores para a sua estimativa. Na falta de melhores informações, ainda hoje, os valores apresentados no referido estudo são utilizados para diversos projetos da Engenharia. Neste trabalho, é apresentada uma nova análise dessas regiões e valores de parâmetros a partir de IDFs atualmente disponíveis. Verificou-se que, de forma geral, as regiões propostas ainda são válidas. No entanto, em diversos locais, os valores propostos apresentam grandes diferenças com relação aos dados atualizados, a exemplo da região Sudeste, em que houve uma intensificação das chuvas de mais curta duração, e a região Centro-Oeste, em que os resultados atuais indicam uma situação oposta. Assim, novos valores para estimativa da chuva intensa são apresentados neste artigo.

Reference flows are important variables for assessing water availability in Brazil, as well as in rural communities in the state of Goiás (Brazil). However, as there is a lack of flowrate data and measurement points, regionalization methods have been used for forecasting the minimum reference flow (Qref) allowed for maintaining water uses. The present research covered 92 hydrographic basins within 46 selected rural communities in the state of Goiás, and 21 basins were selected for carrying out on-site flow measurements, as well as for Qref estimation following three regionalization methodologies. Results show a large variation between the values measured and estimated by the three methodologies, but the statistical analysis found regression equations of one of the methods more suitable for application in rural hydrograph basins of Goiás.

RESUMO O SARS-CoV-2 é facilmente disseminado por aerossóis e contato direto com pessoas contaminadas. Logo, as condições adversas em áreas rurais podem influenciar a propagação do vírus. Desta forma, estabeleceu-se uma reflexão acerca da disseminação da COVID-19 em função do hábito de lavar as mãos, das condições de saneamento, dos aspectos socioeconômicos e das condições habitacionais em 26 comunidades quilombolas rurais do estado de Goiás. Para isso foram levantadas informações in loco em 533 domicílios e aplicou-se a Analytic Hierarchy Process, utilizando-se critérios selecionados com base na literatura. As comunidades apresentaram uma priorização para a disseminação da COVID-19 variando de 14,9 x 10-3 (pior condição) a 64,3 x 10-3 (melhor condição), na qual a Comunidade José Coleto ocupou a posição mais desfavorável. Buracão mostrou um resultado mais satisfatório, sendo esta menos susceptível à disseminação da COVID-19. A melhoria nas condições de saneamento pode aumentar o hábito da higiene com as mãos, o que reduziria a disseminação da COVID-19 e de outras doenças infecciosas. Assim, a partir dos resultados obtidos, é perceptível a importância do empoderamento quanto aos hábitos de higiene, acesso à informação, saneamento básico e à saúde. Os gestores devem ter uma maior disposição para implantar infraestrutura e melhorar as condições dos critérios apresentados e discutidos neste trabalho.

Abstract. The lack of rainfall data in Brazil, and, in particular, in Rio Grande do Sul State (RS), hinders the understanding of the spatial and temporal distribution of rainfall, especially in the case of the more complex extreme events. In this context, rainfall's estimation from remote sensors is seen as alternative to the scarcity of rainfall gauges. However, as they are indirect measures, such estimates needs validation. This paper aims to verify the applicability of the Tropical Rainfall Measuring Mission (TRMM) satellite information for extreme rainfall determination in RS. The analysis was accomplished at different temporal scales that ranged from 5 min to daily rainfall while spatial distribution of rainfall was investigated by means of regionalization. An initial test verified TRMM rainfall estimative against measured rainfall at gauges for 1998-2013 period considering different durations and return periods (RP). Results indicated that, for the RP of 2, 5, 10 and 15 years, TRMM overestimated on average 24.7 % daily rainfall. As TRMM minimum time-steps is 3 h, in order to verify shorter duration rainfall, the TRMM data were adapted to fit Bell's (1969) generalized IDF formula (based on the existence of similarity between the mechanisms of extreme rainfall events as they are associated to convective cells). Bell's equation error against measured precipitation was around 5-10 %, which varied based on location, RP and duration while the coupled BELL+TRMM error was around 10-35 %. However, errors were regionally distributed, allowing a correction to be implemented that reduced by half these values. These findings in turn permitted the use of TRMM+Bell estimates to improve the understanding of spatiotemporal distribution of extreme hydrological rainfall events.

Considering the concept of rurality, the need for methods to contextualize the rural areas and the attendance by sanitation services, the goal of this work was to propose and apply a method of characterization in census sectors (CS) of rural areas. For such, a classification method for rural clusters was built, considering the selected criteria based on the Programa Saneamento Brasil Rural (Rural Brazil Sanitation Program) and other technical-scientific literature. The method encompassed three criteria: the identification of clusters and dispersed households, distance from the cluster to the closest urban center (Cucd) and demographic density (Dd). Of all the 115 rural areas in the state of Goiás, it was possible to apply such in 98, as in the remaining 17 the method could not be directly applied, due to the existence of one or more clusters with the presence of households that do not make part of the rural area, that is, non-contiguous households. In a more detailed analysis, four areas were identified where the method could be applied to a group of households. A total of 103 rural areas were numbered, with an average Cucd of 27.7km (SD = 19.42; CV = 0.70), and average Dd of 50.1 inhabitants per square kilometer, in which 118 clusters were detected. Of that total, 6.79% were classified in the CS 1b and 2, 7.77% on 3 and 85.44% on 5 and 7. It was concluded that the method can be applied integrally in a rural area and/or clusters with contiguous households. Lastly, the classification in CS allows for a preliminary analysis of solution propositions for basic sanitation, being them collective and/or individual, centralized and/or decentralized, according to spacial technical criteria.

Resumo O dimensionamento de estruturas da drenagem pluvial urbana é realizado, normalmente, a partir de dados de chuvas intensas. Essas informações comumente são obtidas por meio das relações intensidade-duração-frequência (IDF), ou na indisponibilidade destas, mediante metodologias simplificadas, tais como as relações entre durações, isozonas de chuvas, ou métodos sintéticos tais como os propostos por Bell (1969) e Chen (1983). Neste artigo é apresentada uma análise da aplicabilidade do método sugerido por Bell, com uma modificação (BACK, 2009), para estimativa de chuvas intensas no Estado do Rio Grande do Sul a partir de informações de chuva diárias, e o uso destas para a determinação de vazões utilizadas no dimensionamento de obras de microdrenagem. Os resultados mostraram que a metodologia de Bell e a modificada segundo Back (2009) estimaram corretamente as chuvas intensas e as vazões de microdrenagem (por sua vez estimadas a partir do método racional) para durações inferiores a 2 horas, quando comparada com informações obtidas diretamente de equações IDFs, em que as variações médias ficaram próximas a 10%. As exceções foram em Espumoso e em Santa Vitória do Palmar, onde superaram os 15% de variação, o que a torna uma opção adequada para o dimensionamento de estruturas da microdrenagem pluvial, quando as relações IDF não estiverem disponíveis.

Abstract. The regional analysis of extreme hydrological events is connected with the availability of a dense network of rainfall data that is absent or inaccessible in Brazil, especially for sub-daily information. In engineering, extreme events rainfall information is represented by intensity-duration-frequency (IDF) relationships which are the most commonly used tools in water resources engineering for planning and design. Even if the sub-daily information that is included in the relationships is not available, the extreme rainfall information rest in the fundamentals of the IDF. This paper analyzes spatial distribution and track changes in sub-daily precipitation over Northeastern (NE) Brazil. Precipitation was estimated from IDF relationships information in Brazil based in rainfall measured from 1920's to 1950's (but still used in engineering projects) and information from the last half of the 20th century obtained from several IDFs gathered from municipalities' manuals, local symposia and books in many cases not easily obtainable. Results showed an intensification of extreme events in recent years, especially in shorter duration rainfall (less than 12 h). Hourly rainfall is bigger in almost all the Brazilian region, but especially in littoral and Northern portion, however, 12 and 24 h rainfall exhibit increases in the North, but, lower values in the Southern half of the region in concordance with flood changes reported by Milly et al. (2005). Analyzing the ratio between 1 and 24 h rainfall is possible to confirm its increase in all the region, with up to 35 % in some areas. These results were able to show insight of sub-daily extreme events changes during 20th century in NE Brazil were previous reports were not found. The results also alerts for the necessity of engineering projects review, as outdated information is still being used for design purposes.

The demand for water has led to an increase in scarcity events in several urban regions. In an urban context, water consumption in buildings plays an important role and rainwater harvesting is one of the ways that consumption can be reduced. One of the input variables for the dimensioning of rainwater tanks is the pluviometric regime's characteristics in the region where the rainwater harvesting system (RWHS) is to be installed. In this study, a bibliometric and systematic literature review was carried out on the types of rainfall data used in the dimensioning of the elements of RWHS. Worldwide, the most-used data comes from meteorological stations, with a historical series size of 30 years, however, other types of data and different sizes of historical series are also used. From this study, it was possible to synthesise the regions where differentiation data can be collected, as well as their characteristics, enabling the researchers to quickly access the definition of separation data collection parameters.