Variabilidad hidroquímica y su relación con el caudal regulado en un estuario tropical: Bahía de Iguape (BA, Brasil)
DOI:
https://doi.org/10.33448/rsd-v15i5.51011Keywords:
Estuarine dynamics, Salinity, Water quality, Regulated discharge, Hydrochemistry.Abstract
The regulation of river discharge by dams represents an important anthropogenic factor with the potential to alter hydrochemical patterns in estuarine systems. The objective of this study was to analyze the spatiotemporal variability of water quality parameters and its relationship with regulated discharge in the Iguape Bay estuary (BA, Brazil), based on monthly sampling conducted at nine sites between September 2023 and October 2024. Salinity, dissolved oxygen, pH, electrical conductivity, and total dissolved solids were measured, and descriptive and multivariate statistical analyses were applied, including Principal Component Analysis (PCA). The results indicated consistent associations between discharge conditions and hydrochemical variability. Periods of lower discharge generally showed higher salinity and ionic concentration values, suggesting greater marine influence, while periods of higher discharge were associated with dilution of salts and improved oxygen conditions. PCA explained 68.4% of the total variability and revealed seasonal patterns consistent with the regional hydrological regime. The results should be interpreted considering limitations related to sampling frequency and the lack of detailed hydrodynamic characterization. Thus, the study does not establish causal relationships, but identifies patterns and associations that contribute to the understanding of hydrochemical variability in tropical estuaries under regulated discharge.
References
Agência Nacional de Águas e Saneamento Básico. (2025). Série histórica de vazão da Barragem Pedra do Cavalo, rio Paraguaçu, Bahia. ANA.
Aguiar, A. O., & Cançado, C. C. (2021). Governança hídrica e conflitos na reserva extrativista marinha Baía de Iguape. Revista de Gestão Social e Ambiental, 14(3).
Bianchi, T. S., Allison, M. A., & Cai, W.-J. (2020). The impact of dam operations on river–estuary–shelf processes in the Mekong Delta: A review. Earth-Science Reviews, 210, 103319. https://doi.org/10.1016/j.earscirev.2020.103319
Brasil. Ministério do Meio Ambiente. (2005). Resolução CONAMA nº 357, de 17 de março de 2005.
Brito, T. S., et al. (2022). Assessment of seasonal and spatial variations in surface water quality of a tropical estuary using multivariate statistical techniques. Environmental Science and Pollution Research, 29, 8450–8466. https://doi.org/10.1007/s11356-021-16393-0
Chen, Z., Xu, H., & Wang, Y. (2021). Ecological degradation of the Yangtze and Nile delta estuaries in response to dam construction. Water, 13, 1145. https://doi.org/10.3390/w13091145
Corrêa, L. J. H. (2016). Monitoramento da qualidade físico-química da água do estuário do Rio Mearim (MA). Revista Brasileira de Recursos Hídricos, 21(3), 210–225.
Costa Neto, P. L. O., & Bekman, O. R. (2009). Análise estatística da decisão (2ª ed.). Editora Blucher.
Darby, S. E., et al. (2023). Impacts of riverine sand mining on freshwater and estuarine systems: A review and future directions. Earth-Science Reviews.
Ezcurra, E., Barrios, E., Ezcurra, P., Ezcurra, A., Vanderplank, S., Vidal, O., & Aburto-Oropeza, O. (2019). A natural experiment reveals the impact of hydroelectric dams on the estuaries of tropical rivers. Science Advances, 5(3), eaau9875. https://doi.org/10.1126/sciadv.aau9875
Fernandes, C. M. (2018). Dinâmica de sólidos dissolvidos em estuários tropicais: estudo no Rio Cocó (CE). Revista Brasileira de Geoquímica, 36(1), 45–58.
Figueroa, S., & Son, M. (2024). Estuarine dams and spillways: Global analysis and synthesis. Marine Geology. https://doi.org/10.1016/j.margeo.2024.107388
Figueroa, S., Lee, G., Chang, J., & Jung, N. (2022). Impact of estuarine dams on sediment flux decomposition: An idealized numerical modeling study. Journal of Geophysical Research: Oceans. https://doi.org/10.1029/2021JC017829
Genz, F., Lessa, G. C., & Cirano, M. (2008). Vazão mínima para estuários: Um estudo de caso no rio Paraguaçu/BA. Revista Brasileira de Recursos Hídricos, 13(3), 73–82.
Gopal, V., et al. (2023). Seasonal variations in water quality and its impacts on benthic fauna in a tropical estuary. Marine Pollution Bulletin, 191, 114925.
Hatje, V., & Andrade, J. B. (2009). Baía de Todos os Santos: Aspectos oceanográficos. EDUFBA.
Maia, L. P., Santos, D. M., Almeida, T. S., & Costa, R. N. (2019). Variação sazonal do oxigênio dissolvido no estuário do Rio Cocó (CE). Revista Brasileira de Engenharia Ambiental, 24(3), 112–120.
Medeiros, P. R. P., et al. (2014). Effects of damming on sediment and nutrient fluxes in tropical estuaries. Journal of Hydrology.
Miranda, L. B., Castro, B. M., & Kjerfve, B. (2002). Princípios de oceanografia física de estuários. São Paulo: EDUSP.
Palinkas, C. M., Testa, J. M., Cornwell, J. C., Li, M., & Sanford, L. P. (2019). Influences of a river dam on delivery and fate of sediments and nutrients to an estuary. Estuaries and Coasts, 42, 2072–2095. https://doi.org/10.1007/s12237-019-00634-x
Pereira, A. S., et al. (2018). Metodologia da pesquisa científica. Editora da UFSM.
Pinto, L. H. S., et al. (2022). Spatial-temporal analysis of water quality in a tropical estuary. Regional Studies in Marine Science, 55, 102546.
Pritchard, D. W. (1952). Estuarine hydrography. Advances in Geophysics, 1, 243–280.
Prost, C. Efeitos da barragem Pedra do Cavalo sobre a pesca artesanal na baía do Iguape. Encontro Brasileiro de Ciências Sociais sobre Barragens, 2, 2007.
https://www.researchgate.net/publication/317318661_Efeitos_da_barragem_da_Pedra_do_Cavalo_ sobre_a_pesca_artesanal_na_baia_do_Iguape.
Rakib, M. R. J., et al. (2021). Salinity intrusion in the Bengal Delta: Challenges and solutions. Ocean & Coastal Management, 202, 105493.
Reis, S. A., & Bellini, L. M. (2016). Impactos de represas em sistemas hidrográficos. Ambiente e Educação, 21(1), 155–176.
Risemberg, R. I. C., et al. (2026). A importância da metodologia científica no desenvolvimento de artigos científicos. E-Acadêmica, 7(1), e0171675. https://eacademica.org/eacademica/article/view/675
Shitsuka, R., et al. (2014). Matemática fundamental para tecnologia (2ª ed.). Editora Érica.
Silva, T. R., Couto, G. A., Campos, V. P., & Medeiros, Y. D. P. (2015). Influência do regime de vazão da usina hidrelétrica de Pedra do Cavalo no comportamento espacial e temporal da salinidade no trecho fluvioestuarino do baixo curso do rio Paraguaçu à Baía do Iguape. Revista Brasileira de Recursos Hídricos, 20(2), 310–319.
Xia, Y., et al. (2023). Response of salinity intrusion to river discharge and wind forcing in a mesotidal estuary. Estuarine, Coastal and Shelf Science.
Yang, F., et al. (2024). Impacts of artificial regulation on nutrient transport in large river systems. Journal of Oceanology and Limnology.
Yi, Y., Gao, Y., Wu, X., Jia, W., & Liu, Q. (2023). Modeling the effect of artificial flow and sediment flux on estuarine ecosystems. International Journal of Sediment Research.
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