Modelagem Numérica e Avaliação Hidrogeológica do Aquífero Rio Claro
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Data
2016-10-04
Autores
Dias Gonçalves, Roger
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A gestão adequada dos recursos hídricos é peça-chave para o desenvolvimento de uma região, seja urbana ou agrícola. O conhecimento acerca do impacto das mudanças climáticas e as diferentes atividades humanas sobre os recursos hídricos, em especial as águas subterrâneas, tornou-se essencial para tomadas de decisão corretas e sustentáveis. O Aquífero Rio Claro, localizado no município homônimo, é um aquífero raso e livre, composto por um pacote pouco espesso e predominantemente arenoso da Formação Rio Claro. Possui água naturalmente de boa qualidade e grande parte deste reservatório estende-se sob a área urbana do município. Este estudo estima os impactos da seca de 2013/2014 e o potencial de explotação do aquífero através do uso de modelagem numérica. Para as simulações utilizou-se o método dos elementos finitos por meio do algoritmo Feflow. A porção norte da área, mais agrícola, compreende a principal área de recarga do aquífero, enquanto que a porção sul é mais urbanizada e apresenta um grau de impermeabilização maior, que impacta negativamente as taxas de recarga. O balanço de fluxo calculou uma perda de 5,3% da água do armazenamento do aquífero durante o período de seca, que representou, na região, uma precipitação quase 30% menor que a média histórica. A grande maioria dos poços cadastrados no município extrai água de aquíferos mais profundos, perfazendo cerca de 450 m³/h. Em um cenário no qual o Aquífero Rio Claro fosse responsável por toda essa demanda de água subterrânea durante todo o período de seca, o aquífero perderia cerca de 6,6% da água de seu armazenamento. O bombeamento dos poços atingiria aproximadamente 19% da recarga do aquífero, portanto, o aquífero tem potencial para comportar tal volume de explotação. No entanto, a concentração dos poços no distrito industrial e na área urbana do município representa um alto risco para o aquífero e para o abastecimento nestas áreas, com alteração da dinâmica de fluxo entre as porções norte e sul e interferência nas vazões dos poços.
Proper management of water resources is a key player in regional development, whether urban or agricultural. The knowledge about the impacts of climate changes and human activities on water resources, especially groundwater, it has become essential for making correct and sustainable decisions. The Rio Claro Aquifer, located in the homonymous city, is a shallow and unconfined aquifer, composed of a thin layer of Rio Claro Formation sandstones. It has good quality water in natural conditions and a significant part of this reservoir is located below the urban area. This study estimated the impacts of the drought of 2013-2014 and the potential exploitation of the aquifer using numerical modeling. Finite elements method by Feflow algorithm was used for the simulation. The northern portion, more agricultural, encompasses the main recharge area, while the southern portion is more urbanized and has a higher waterproofing coverage impacting negatively on the recharge rates. The water budget showed a loss of 5.3% of the aquifer storage during the dry season. The precipitation was almost 30% lower than the average in this region. The majority of registered wells in the city extracts water from deeper aquifers reaching about 450 m³/h. In a scenario in which the Rio Claro Aquifer is responsible for all groundwater demand throughout the dry season, the aquifer would lose about 6.6% of its water storage. The pumping wells reaches approximately 19% of the aquifer recharge, therefore the aquifer can support this exploitation volume. However, the spatial concentration of the wells in the industrial district and the urban area pose a high risk to the aquifer and the groundwater supply in these areas, by changing the water flow dynamics between the northern and southern portions and interference in the well rates.
Proper management of water resources is a key player in regional development, whether urban or agricultural. The knowledge about the impacts of climate changes and human activities on water resources, especially groundwater, it has become essential for making correct and sustainable decisions. The Rio Claro Aquifer, located in the homonymous city, is a shallow and unconfined aquifer, composed of a thin layer of Rio Claro Formation sandstones. It has good quality water in natural conditions and a significant part of this reservoir is located below the urban area. This study estimated the impacts of the drought of 2013-2014 and the potential exploitation of the aquifer using numerical modeling. Finite elements method by Feflow algorithm was used for the simulation. The northern portion, more agricultural, encompasses the main recharge area, while the southern portion is more urbanized and has a higher waterproofing coverage impacting negatively on the recharge rates. The water budget showed a loss of 5.3% of the aquifer storage during the dry season. The precipitation was almost 30% lower than the average in this region. The majority of registered wells in the city extracts water from deeper aquifers reaching about 450 m³/h. In a scenario in which the Rio Claro Aquifer is responsible for all groundwater demand throughout the dry season, the aquifer would lose about 6.6% of its water storage. The pumping wells reaches approximately 19% of the aquifer recharge, therefore the aquifer can support this exploitation volume. However, the spatial concentration of the wells in the industrial district and the urban area pose a high risk to the aquifer and the groundwater supply in these areas, by changing the water flow dynamics between the northern and southern portions and interference in the well rates.
Descrição
Palavras-chave
Águas Subterrâneas, Simulação Numérica, Aquífero Rio Claro, Feflow, Avaliação Hidrogeológica, Groundwater, Numerical simulation, Hydrogeological assessment