IJG  Vol.5 No.9 , August 2014
Influence of the Freshwater Discharge on the Hydrodynamics of Patos Lagoon, Brazil
ABSTRACT

Patos Lagoon is a very dynamic environment presenting hydrodynamic fluctuations from synoptic to decadal timescales. Thus, understanding the processes that determine the long term variability is fundamental for the correct coastal planning and management of this region. The main objective of this study is to understand how the freshwater discharge of the main tributaries controls the estuarine hydrodynamics of the Patos Lagoon, when considering long term timescales. Two numerical simulations were carried out using the TELEMAC3D numerical model, the former using freshwater discharge from 1940 to 1973 year (simulation A), and the second simulation using data between 1974 and 2006 year (simulation B). These two periods were selected because before (after) 1973 year, the annual mean freshwater discharge was lower (higher) than the mean value for the whole period (1080 m3/s). The navigational channel discharge, water level, salinity and current velocity differences between both simulations were analyzed. Ebb conditions prevailed over flood conditions for both simulations, but simulation B presented a higher volume of freshwater exported through the coastal zone. Water level differences demonstrated higher values (0.08 meters) close to the Guaiba River, which is the main tributary of the study region, and lower values were observed near to the Patos Lagoon mouth (0 meters). The most significant differences in the mean bottom and surface salinity were observed in the central zone of the estuary and at the Barra Breakwaters. Simulation A presented higher saline intrusion due to lower freshwater discharge, while simulation B showed an increase in the coastal plume intensity, caused by the higher freshwater discharge. The hydrodynamical simulations demonstrated with precision that the freshwater discharge intensity determine the vertical stratification of the estuary.


Cite this paper
Barros, G. , Marques, W. and Kirinus, E. (2014) Influence of the Freshwater Discharge on the Hydrodynamics of Patos Lagoon, Brazil. International Journal of Geosciences, 5, 925-942. doi: 10.4236/ijg.2014.59080.
References
[1]   Miranda, L.B., Belmiro, M.C. and Kjerfve, B. (2002) Principios de Oceanografia Fisica de Estuarios. USP, Sao Paulo.

[2]   Moller, O.O., Castaing, P., Salomon, J.C. and Lazure, P. (2001) The Influence of Local and Non-Local Forcing Effects on the Sub Tidal Circulation of Patos Lagoon. Estuaries, 24, 297-311.
http://dx.doi.org/10.2307/1352953

[3]   Grimm, A.M., Barros, V.R. and Doyle, M.E. (2000) Climate Variability in Southern South America Associated with El Nino and La Nina Events. Journal of Climate, 13, 35-58.
http://dx.doi.org/10.1175/1520-0442(2000)013<0035:CVISSA>2.0.CO;2

[4]   Dettinger, M.D., Battisti, D.S., Mccabe, G.J., Bitz, C.M. and Gerreaud, R.D. (2001) Interhemispheric Effects of Inter-Annual and Decadal ENSO-Like Climate Variations on the Americas. In: Markgref, V., Ed., Interhemispheric Climate Linkages: Present and Past Climates in the Americas their Societal Effects, Academic Press, 1-16.
http://dx.doi.org/10.1016/B978-012472670-3/50004-5

[5]   Timmermann, A., Oberhuber, J., Bacher, A., Esch, M., Latif, M. and Roeckner, E. (1999) Increased El Nino Frequency in a Climate Model Forced by Future Greenhouse Warming. Nature, 398, 694-697.
http://dx.doi.org/10.1038/19505

[6]   Grimm, A.M., Ferraz, S.E.T. and Julio, G. (1998) Precipitation Anomalies in Southern Brazil Associated with El Nino and La Nina Events. Journal of Climate, 11, 2863-2880.
http://dx.doi.org/10.1175/1520-0442(1998)011<2863:PAISBA>2.0.CO;2

[7]   Montecinos, A., Diaz, A. and Aceituno, P. (2000) Seasonal Diagnostic and Predictability of Rainfall in Subtropical South America Base on Tropical Pacific SST. Journal of Climate, 13, 746-758.
http://dx.doi.org/10.1175/1520-0442(2000)013<0746:SDAPOR>2.0.CO;2

[8]   Tagliani, C.R., Calliari, L.J., Tagliani, P.R. and Antiqueira, J. A. (2010) Vulnerability to Sea Level Rise of an Estuarine Island in Southern Brazil. Quaternary and Environmental Geosciences, 1, 18-24.

[9]   Marques, W.C., Fernandes, E.H., Monteiro, I.O. and Moller, O.O. (2009) Numerical Modeling of the Patos Lagoon Coastal Plume, Brazil. Continental Shelf Research, 29, 556-571.
http://dx.doi.org/10.1016/j.csr.2008.09.022

[10]   Moller, O.O., Castello, J.P. and Vaz, A.C. (2009) The Effect of River Discharge and Winds on the Interannual Variability of the Pink Shrimp Farfantepenaeus paulensis Production in Patos Lagoon. Estuaries and Coasts, 32, 787-796.
http://dx.doi.org/10.1007/s12237-009-9168-6

[11]   Moller, O.O. and Castaing, P. (1999) Hydrographical Characteristics of the Estuarine Area of Patos Lagoon (30°S, Brazil). Estuaries of South America, 5, 83-100.
http://dx.doi.org/10.1007/978-3-642-60131-6_5

[12]   Collins, M., An, S.I., Cai, W., Ganachaud, A., Guilyardi, E., Jin, F.F., Jochum, M., Lengaigne, M., Power, S., Timmermann, A., Vecchi, G. and Wittenberg, A. (2010) The Impact of Global Warming on the Tropical Pacific Ocean and El Nino. Nature Geoscience, 3, 391-397.
http://dx.doi.org/10.1038/ngeo868

[13]   Kjerfve, B. (1994) Coastal Lagoons. In: Kjerfve, B., Ed., Coastal Lagoon Processes, Elsevier Oceanographic Series, Amsterdam, 1-8.

[14]   Delaney, P. (1965) Fisiografia e Geologia de Superficie da Planicie Costeira do Rio Grande do Sul. Publicacao Especial da Escola de Geologia de Porto Alegre, 6, 1-105.

[15]   Barros, G.P. and Marques, W.C. (2012) Long-Term Temporal Variability of the Freshwater Discharge and Water Levels at Patos Lagoon, Rio Grande do Sul, Brasil. International Journal of Geophysics, 2012, Article ID: 459497.
http://dx.doi.org/10.1155/2012/459497

[16]   Hervouet, J.M. and Van Haren, L. (1994) TELEMAC-2D Principle Note. Rapport HE-43/94/051/B. Electricite de France. Chatou Cedex, Departement Laboratoire National d’Hydraulique.

[17]   Marques, W.C., Fernandes, E.H. and Rocha, L.A.O. (2011) Straining and Advection Contributions to the Mixing Process of the Patos Lagoon Estuary, Brazil. Journal of Geophysical Research: Ocean, 116.
http://dx.doi.org/10.1029/2010JC006524

[18]   Marques, W.C., Fernandes, E.H., Monteiro, I.O. and Moller, O.O. (2009) Numerical Modeling of the Patos Lagoon Coastal Plume, Brazil. Continental Shelf Research, 29, 556-571.
http://dx.doi.org/10.1016/j.csr.2008.09.022

[19]   Marques, W.C., Fernandes, E.H., Moraes, B.C., Moller, O.O. and Malcherek, A. (2010) Dynamics of the Patos Lagoon Coastal Plume and Its Contribution to the Deposition Pattern of the Southern Brazilian Inner Shelf. Journal of Geophysical Research, 115, 1-22.
http://dx.doi.org/10.1029/2010JC006190

[20]   Marques, W.C., Fernandes, E.H., Rocha, L.A.O. and Malcherek, A. (2012) Energy Converting Structures in the Southern Brazilian Shelf: Energy Conversion and Its Influence on the Hydrodynamic and Morphodynamic Processes. Journal of Earth Sciences and Geotechnical Engineering, 1, 61-85.

[21]   Fernandes, E.H.L., Marino-Tapia, I., Dyer, K.R. and Moller, O.O. (2004) The Attenuation of Tidal and Subtidal Oscillations in the Patos Lagoon Estuary. Ocean Dynamics, 54, 348-359.
http://dx.doi.org/10.1007/s10236-004-0090-y

[22]   Marques, W.C. (2012) The Temporal Variability of the Freshwater Discharge and Water Levels at the Patos Lagoon, Brazil. International Journal of Geosciences, 3, 758-766.
http://dx.doi.org/10.4236/ijg.2012.34076

[23]   Marques, W.C., Stringari, C.E. and Eidt, R.T. (2014) The Exchange Processes of the Patos Lagoon Estuary—Brazil: A Typical El Nino Year versus a Normal Meteorological Conditions Year. Advances in Water Resource and Protection, 2, 11-19.

[24]   Bemvenuti, C.E. and Colling, L.A. (2010) As Comunidades de Macroinvertebrados Bentonicos. In: Seelinger, U. and Odebrecht, C., Eds., O Estuario da Lagoa dos Patos: Um seculo de transformacoes, FURG, Rio Grande, 101-116.

[25]   Monteiro, I.O., Pearson, M.L., Moller Jr., O.O. and Fernandes, E.H.L. (2005) Hidrodinamica do Saco da Mangueira: Mecanismos que Controlam as Trocas com o Estuario da Lagoa dos Patos. Atlantica, 27, 87-101.

[26]   Abreu, P.C., Odebrecht, C. and Niecheski, L.F. (2010) Nutrientes Dissolvidos. In: Seelinger, U. and Odebrecht, C., Eds., O Estuario da Lagoa dos Patos: Um seculo de transformacoes, FURG, Rio Grande, 43-50.

[27]   Moller, O. and Fernandes, E. (2010) Hidrologia e Hidrodinamica. In: Seelinger, U. and Odebrecht, C., Eds., O Estuario da Lagoa dos Patos: Um seculo de transformacoes, FURG, Rio Grande, 17-30.

[28]   Vieira, J.P., Garcia, A. and Moraes, L. (2010) A Assembleia de Peixes. In: Seelinger, U. and Odebrecht, C., Eds., O Estuario da Lagoa dos Patos: Um seculo de transformacoes, FURG, Rio Grande, 79-90.

[29]   Niencheski, L.F., Windom, H.L. and Smith, R. (1994) Distribution of Particulate Trace Metal in Patos Lagoon Estuary (Brazil). Marine Pollution Bulletin, 28, 96-102.
http://dx.doi.org/10.1016/0025-326X(94)90545-2

[30]   Liu, W.C., Hsu, M.H., Kuo, A.Y. and Kuo, J.T. (2001) The Influence of River Discharge on Salinity Intrusion in the Tanshui Estuary, Taiwan. Journal of Coastal Research, 17, 544-552.

[31]   Odebrecht, C., Bergesch, M., Medeanic, S. and Abreu, P.C. (2010) A Comunidade de Microalgas. In: Seelinger, U. and Odebrecht, C., Eds., O Estuario da Lagoa dos Patos: Um seculo de transformacoes, FURG, Rio Grande, 51-66.

[32]   Liu, W.C., Chen, W.B., Cheng, R.T., Hsu, M.H. and Kuo, A.Y. (2007) Modeling the Influence of River Discharge on Salt Intrusion and Residual Circulation in Danshuei River Estuary, Taiwan. Continental Shelf Research, 27, 900-921.
http://dx.doi.org/10.1016/j.csr.2006.12.005

[33]   Dat, T.Q., Likitdecharote, K., Srisatit, T. and Trung, N.H. (2011) Modeling the Influence of River Discharge and Sea Level Rise on Salinity Intrusion in Meking Delta. Environmental Supporting in Food and Energy Security: Crisis and Opportunity, 35, 685-701.

[34]   Garrison, T. (2009) Essentials of Oceanography. 5th Edition, Brooks/Cole, Cengage Learning, Belmont.

[35]   Abrosimova, A., Zhabin, I. and Dubina, V. (2009) Influence of Amur River Discharge on Hydrological Conditions of the Amurskiy Liman and Sakhalin Bay of the Sea of Okhotsk during a Spring-Summer Flood. PICES Scientific Report, 36, 180-184.

[36]   Chant, R.J. and Wilson, R.E. (2000) Internal Hydraulics and Mixing in a Highly Stratified Estuary. Journal of Geophysical Research: Ocean, 105, 14215-14222.
http://dx.doi.org/10.1029/2000JC900049

[37]   Liu, W.C., Chen, W.B. and Hsu, M.H. (2011) Influences of Discharge Reductions on Salt Water Intrusion and Residual Circulation in Danshuei River. Journal of Marine Science and Technology, 19, 596-606.

[38]   Garvine, R.W. (1977) Observations of the Motion Field of the Connecticut River Plume. Journal of Geophysical Research, 82,441-454.
http://dx.doi.org/10.1029/JC082i003p00441

[39]   Dyer, K.R. (1991) Circulation and Mixing in Stratified Estuaries. Marine Chemistry, 32, 111-120.
http://dx.doi.org/10.1016/0304-4203(91)90031-Q

 
 
Top