Estudo da variabilidade espacial e temporal do nível estático e superfície potenciométrica das águas do aquífero bauru no município de São José do Rio Preto - SP (2013-2019)
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2021-01-22
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Universidade Estadual Paulista (Unesp)
Resumo
A pressão sobre os recursos hídricos subterrâneos está relacionada ao crescimento populacional e urbano, pois é essencial para o desenvolvimento das atividades agrícolas, industriais e abastecimento público das cidades. Tendo em vista a supervalorização da água subterrânea como sendo fonte de recurso protegida de poluição e inesgotável, torna-se fundamental a condução de pesquisas visando o monitoramento da disponibilidade deste recurso. O município de São José do Rio Preto (SP) depende majoritariamente de água subterrânea e, principalmente, das águas do Sistema Aquífero Bauru (50%) por apresentar facilidade construtiva e operacional de poços tubulares, seguidos do Aquífero Guarani (28%) (Formação Botucatu/Pirambóia), além de afluentes e corpos d’água maiores como o Rio Preto (22%) para abastecimento público ou privado. Tendo em vista a demanda no município pelo Aquífero Bauru, a pesquisa focou em dados de poços que utilizam esse aquífero em razão do número de registro para os períodos 2013-2019, sendo estes fornecidos pelo Serviço Municipal Autônomo de Água e Esgoto (SEMAE). O estudo avaliou a variabilidade espacial e temporal do Nível Estático (NE) e Nível Potenciométrico (NP) aplicando os conceitos da geoestatística. Para tal, foram realizadas análises descritivas e geoestatística através do cálculo de variogramas experimentais, por meio do qual foi avaliada a dependência espacial e gerada interpolação por krigagem ordinária. Os resultados obtidos da análise descritiva para o NE, em todos os períodos, mostrou elevados Coeficientes de Variação (CV), com o CV do NE anual, entre 28,48 % (2015) a 38,50% (2014), em análises sazonais, período de Excedente Hídrico (EH), de 35,06% (2019) a 39,71% (2018) e para o período de Deficiência Hídrica (DH), 25,36% (2017) a 35,46% (2016). Foi observada elevada variação dos dados, provavelmente em função da característica física do meio em que o poço se localiza (do solo ou a variação do relevo), mas principalmente devido aos períodos de avaliação, uma vez que as amostras foram coletadas em dias diferentes dentro do mesmo período, o que corrobora com valores mais distintos e um CV mais elevado; enquanto que para o NP o CV foi menor. Os valores médios do NE para os períodos anuais parecem indicar de modo geral uma tendência do aprofundamento do NE ao longo do período.
The pressure on groundwater resources is related to populational and urban growth, as it is essential for the development of agricultural, industrial and public supply of cities. Regarding the overvaluation of groundwater as a source of resource protected from pollution and inexhaustible, it is essential to conduct research aimed at monitoring the availability of this resource. The municipality of Sao Jose do Rio Preto (SP) depends mostly on groundwater and, mainly, on the waters of the Bauru Aquifer System (50%) for presenting constructive and operational ease of tubular wells, followed by the Guarani Aquifer (28%) (Botucatu / Piramboia Formation), in addition to tributaries and larger water bodies such as the Rio Preto (22%) for public or private supply. In view of the demand in the municipality for the Bauru Aquifer, this research focused on data from wells that use this aquifer due to the registration number for the periods 2013-2019, which are provided by the Autonomous Municipal Water and Sewage Service (AMWSS). The study evaluated the spatial and temporal variability of the Static Level (SL) and Potentiometric Level (PL) by applying geostatistics concepts. Thus, descriptive and geostatistical analyzes were carried out through the calculation of experimental variograms, through which spatial dependence was evaluated and interpolation generated by ordinary kriging. The results obtained from the descriptive analysis for the SL, in all periods, showed high Coefficients of Variation (CV), with the annual SL CV, from 28,48% (2015) to 38,50% (2014), in analyzes seasonal, period of Water Surplus (WS), from 35,06% (2019) to 39,71% (2018) and for the period of Water Deficiency (WH), 25,36% (2017) to 35,46% (2016). High data variation was observed, probably due to the physical characteristic of the environment in which the well is located (soil or relief variation), but mainly due to the evaluation periods, since the samples were collected on different days within from the same period, which corroborates with different values and a higher CV; while for the PL the CV was lower. The average values of the SL for the annual periods seem to indicate in general a trend of deepening in the SL over the period.
The pressure on groundwater resources is related to populational and urban growth, as it is essential for the development of agricultural, industrial and public supply of cities. Regarding the overvaluation of groundwater as a source of resource protected from pollution and inexhaustible, it is essential to conduct research aimed at monitoring the availability of this resource. The municipality of Sao Jose do Rio Preto (SP) depends mostly on groundwater and, mainly, on the waters of the Bauru Aquifer System (50%) for presenting constructive and operational ease of tubular wells, followed by the Guarani Aquifer (28%) (Botucatu / Piramboia Formation), in addition to tributaries and larger water bodies such as the Rio Preto (22%) for public or private supply. In view of the demand in the municipality for the Bauru Aquifer, this research focused on data from wells that use this aquifer due to the registration number for the periods 2013-2019, which are provided by the Autonomous Municipal Water and Sewage Service (AMWSS). The study evaluated the spatial and temporal variability of the Static Level (SL) and Potentiometric Level (PL) by applying geostatistics concepts. Thus, descriptive and geostatistical analyzes were carried out through the calculation of experimental variograms, through which spatial dependence was evaluated and interpolation generated by ordinary kriging. The results obtained from the descriptive analysis for the SL, in all periods, showed high Coefficients of Variation (CV), with the annual SL CV, from 28,48% (2015) to 38,50% (2014), in analyzes seasonal, period of Water Surplus (WS), from 35,06% (2019) to 39,71% (2018) and for the period of Water Deficiency (WH), 25,36% (2017) to 35,46% (2016). High data variation was observed, probably due to the physical characteristic of the environment in which the well is located (soil or relief variation), but mainly due to the evaluation periods, since the samples were collected on different days within from the same period, which corroborates with different values and a higher CV; while for the PL the CV was lower. The average values of the SL for the annual periods seem to indicate in general a trend of deepening in the SL over the period.
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Palavras-chave
Água subterrânea, Krigagem ordinária, Groundwater, Ordinary kriging, Water resources management, Gestão dos recursos hídricos