Impactos ambientais e sociais na bacia hidrográfica do Rio Paraíba decorrentes do uso do solo e da transposição do Rio São Francisco

Abstract

The objective of this work was to identify the environmentaland social impacts in the Paraíba River basin due to the use of the soil and the transposition of the São Francisco River, which generate impacts to water quality, proposing actions that allow adequate management of water resources. For the identification of impacts, semi-structured interviews were conducted with municipalities managers and population living in areas near the Paraíba river. The water quality analyzes were performed in 12 sampling points, corresponding to 4 reservoirs and 8 points in the river channel, between March 2016 and January 2017, and May and July 2017, after the transposition of the waters of the São Francisco river. Several impacts of rural and urban origin were identified, the first being mainly related to the use of indiscriminate fertilizers and agrochemicals. For the urban environment was highlighted the release of domestic effluents, resulting from the absence or insufficiency of effluent collection and treatment systems. Regarding water quality, the Camalaú and Epitácio Pessoa reservoirs presented higher water quality, which were associated to the high transparency of the water, the presence of submerged macrophytes and the tucunaré fish. For the points located in the river bed, it was evident the interference of the cities, after the urban agglomerations, the water presented inferior quality to water collected before the river to cross the city. The transposition of the waters of the São Francisco river to the Paraíba River has altered the quality of the water in the reservoirs. It was observed the increase in nutrient concentration, mainly Total Phosphorus, Phosphate and Ammonia in the three studied reservoirs, Nitrate in Potions Reservoir and Nitrite in Epitácio Pessoa Reservoir. The increase in the water volumes in the dams did not, during the study, improve the Indexes of Trophic States observed in the dams before transposition. Even though during the Transposition works, negative impacts were generated, the arrival of the waters in Paraíba rekindled the hope of the population that depends on the waters of the river, highlighting the need for good management to this resource in the region.