No abstract

Knowing the temporal and spatial variability of the probability of rainfall occurrence is indispensable for the planning and management of agricultural and agroindustrial activities. This study aims to evaluate the applicability of four cumulative distribution functions (CDFs; exponential, two-parameter exponential, mixed exponential, and gamma) to estimate the probability of daily rainfall in the Tocantins-Araguaia hydrographic region (TAHR). The CDFs were applied to 196 rainfall gauge stations distributed in three homogeneous regions (HRs) of rainfall in the TAHR. In relation to the CDFs, the Kolmogorov-Smirnov test and the probability-probability plot showed that the mixed exponential best adhered to the observed data for most of the months of the year in the three HRs that were analyzed. In the few months that this function did not have a good statistical performance, the gamma function was the one with the best fit quality. This study can be used as a guide for studies in other river basins in Brazil and around the world to estimate CDFs of daily rainfall. Recommendations for Resource Managers• Stochastic models using cumulative distribution functions (CDFs) allow the simulation of rainfall data by means of their frequency of occurrence. Some CDFs have been used to verify the behavior and variability of precipitation over the years. For example, the mixed exponential, the Weibull with two parameters, the generalized Pareto, the lognormal, and the gamma with two parameters.• Daily rainfall modeling is important to recognize the occurrence patterns for the prediction of the climatic behavior of a region. Sectors such as agriculture, flood control, and human supply projects need knowledge of precipitation for planning, management, and operation.• The knowledge of the rainfall behavior is very important in Tocantins-Araguaia hydrographic region because it is located in the arc of deforestation in the Amazon. In this case, the dry season and temperatures have been increasing due to global climate change and deforestation itself. K E Y W O R D S adherence test, agroindustrial activities, ecotone, homogeneous regions, water resources

No semiárido brasileiro, os habitantes convivem com limitações hídricas, situação que se torna mais grave quando é analisado o contexto da área rural. Este artigo tem como objetivo analisar a situação da população rural do município de Pombal-PB no que tange a sustentabilidade hídrica. A área de estudo da pesquisa abrangeu 14 (quatorze) comunidades rurais localizadas no município citado. Foram utilizados indicadores que são aplicados em estudos regionais e locais associando à temática gestão de recursos hídricos com aspectos socioeconômicos em municípios e comunidades rurais. Os dados de entrada para o cálculo do Índice de Sustentabilidade Hídrica Rural (ISHR) foram obtidos através da realização de entrevistas com base em um roteiro de temas em um questionário estruturado fechado a 88 indivíduos residentes nas comunidades selecionadas. Para o cálculo do ISHR foi envolvido ponderações, em que as notas das variáveis dos indicadores e os pesos das dimensões e subdimensões foram definidos e analisados pela aplicação do método Delphi. Os resultados indicaram que o valor médio do ISHR para 14 comunidades foi de 5,6, com desvio padrão de 0,25 e, coeficiente de variação de 4,47%. Os resultados do ISHR mostraram que todas as comunidades são classificadas dentro de uma faixa regular com relação à sustentabilidade hídrica. O ISHR pode ser empregado como uma ferramenta para ajudar os tomadores de decisões no setor hídrico na escolha de prioridades e criação de políticas, estratégias e ações para as comunidades rurais.

No abstract

In some coastal areas, tidal ranges represent an important energy potential. This energy is harnessed through tidal power plants (TPPs), which cause environmental impacts during the construction and operation phases. The objective is to propose an environmental impact potential (EIP) index to be used as a tool to select suitable areas for the installation of TPPs. The EIP is based on a combination of geographic information systems and multicriteria analysis, which take into account the degrees of vulnerability of the following environmental variables: land use, geomorphology, geology, slope, pedology and vegetation. The results showed that the EIP values in most areas of the Amazon region coast decrease from north to south, and 15% of the areas had low EIP values because they are farther from estuaries, which are technically better for the implementation of TPPs. In the rest of the region, 82% of the areas have average EIP values, and 3% have high EIP values. These areas are near the mouth and are more susceptible to erosion and flooding. In this case, the environmental impact is greater in relation to those of areas with the greatest river influence. Thus, from an environmental point of view, the EIP index has proven to be a preliminary and simple application assessment tool for choosing the best area for TPP installation for the sustainable use of natural resources.