Influência do uso e ocupação do solo na disponibilidade hídrica das bacias dos rios Peruípe, Itanhém e Jucuruçu, Bahia

Resumo

O processo de modificação da paisagem através da retirada da vegetação nativa para a implantação de atividade antrópicas acarreta alterações no comportamento hidrológico de uma bacia hidrográfica. Diante disso, este trabalho teve como objetivo analisar a influência da alteração do uso e ocupação do solo na disponibilidade hídrica das bacias hidrográficas dos rios Peruípe, Itanhém e Jucuruçu, no período de 1990 a 2018. Para tanto, utilizou-se dados das séries históricas das estações fluviométricas localizadas nas áreas de drenagem das bacias, importadas do portal HidroWeb da Agência Nacional de Águas e Saneamento Básico (ANA). A partir destas, foram obtidas as variáveis hidrológicas anuais: vazão máxima, vazão média e mínima. Já os dados de uso e ocupação do solo foram cedidos pelo Fórum Florestal do Extremo Sul da Bahia e estes passaram por processamento no software QGIS, onde foram obtidas as áreas de cada classe de uso e ocupação do solo. Posteriormente, fez-se a associação dos dados através de análise quantitativa executada no software SAS, onde foram obtidas as correlações simples entre as variáveis. As formas de uso do solo nas bacias hidrográficas estudadas passaram por significativa redução das áreas de vegetação nativa em virtude do crescimento das áreas de atividades antrópicas, principalmente as destinadas a pecuária e silvicultura. A análise de correlação demonstrou que a expansão dessas áreas tem influenciado a diminuição das vazões mínimas. Em contrapartida, apesar da diminuição significativa das áreas de vegetação nativa, os remanescentes florestais continuam atuando na redução das vazões máximas e aumento das vazões mínimas. 

Influence of land use and occupation on water availability in the Peruípe, Itanhém and Jucuruçu river basins, Bahia

ABSTRACT

The process of modifying the landscape through the removal of native vegetation for the implementation of anthropic activities causes changes in the hydrological behavior of a hydrographic basin. In view of this, this study aimed to analyze the influence of changes in land use and occupation on the water availability of the hydrographic basins of the Peruípe, Itanhém and Jucuruçu rivers, from 1990 to 2018. For this purpose, data from the historical series were used. the fluviometric stations belonging to the drainage areas of the basins, imported from the HidroWeb portal of the National Water Agency. From these, the hydrological variables were obtained: maximum flow, average and minimum flow. The data on land use and occupation were provided by the Forest Forum of the Extreme South of Bahia and these were processed in the QGIS software, where the areas of each class of land use and occupation were obtained. Subsequently, the association of the data was made through quantitative analysis performed in the software SAS University Edition, where simple correlations between variables were obtained. The forms of land use and occupation in the hydrographic basins studied underwent a significant reduction in the areas of native vegetation due to the growth of the areas of anthropic activities, mainly those destined for livestock and forestry. The correlation analysis showed that the expansion of these areas has influenced the decrease in minimum flows. On the other hand, despite the significant decrease in the areas of native vegetation, the forest remnants continue to act in reducing maximum flows and increasing minimum flows.

Influence of land use and occupation on water availability in the Peruípe, Itanhém and Jucuruçu river basins, Bahia

A B S T R A C T

The process of modifying the landscape through the removal of native vegetation for the implementation of anthropic activities causes changes in the hydrological behavior of a hydrographic basin. In view of this, this study aimed to analyze the influence of changes in land use and occupation on the water availability of the hydrographic basins of the Peruípe, Itanhém and Jucuruçu rivers, from 1990 to 2018. For this purpose, data from the historical series were used. the fluviometric stations belonging to the drainage areas of the basins, imported from the HidroWeb portal of the National Water Agency. From these, the hydrological variables were obtained: maximum flow, average and minimum flow. The data on land use and occupation were provided by the Forest Forum of the Extreme South of Bahia and these were processed in the QGIS software, where the areas of each class of land use and occupation were obtained. Subsequently, the association of the data was made through quantitative analysis performed in the software SAS University Edition, where simple correlations between variables were obtained. The forms of land use and occupation in the hydrographic basins studied underwent a significant reduction in the areas of native vegetation due to the growth of the areas of anthropic activities, mainly those destined for livestock and forestry. The correlation analysis showed that the expansion of these areas has influenced the decrease in minimum flows. On the other hand, despite the significant decrease in the areas of native vegetation, the forest remnants continue to act in reducing maximum flows and increasing minimum flows.

Keywords: geoprocessing, hydrological behavior, water inertia.