Abstract
Saltwater intrusion typically develops in the along-channel direction but exceptions can be found in bifurcated estuaries. Based on the observational data, we found that the saltwater intrusion in the upper reaches of the North Channel (NC) of Changjiang Estuary is dominated by the lateral saltwater intrusion from a small northern outlet (denoted as NONC) of this channel. This phenomenon has severe effects on the freshwater usage in this region. To investigate the underlying mechanisms of this pattern of intrusion, numerical experiments were conducted using a well-validated model. A flux decomposing method was used to decompose the process of saltwater intrusion into several mechanisms. During the neap tide, the saltwater begins to intrude landward into the NONC through shear transport induced by estuarine circulation. During the transition period between the neap tide and the following spring tide, the saltwater that previously reached the NONC further intrudes into the NC via Lagrangian and tidal pum** transports, causing a significant salinity increase in the middle and upper reaches of the NC. During the spring tide and the subsequent middle tide, saltwater intrusion in the NONC retreats. The impacts of the topography of the NONC and the wind stress on this lateral saltwater intrusion were also evaluated in this study.
Similar content being viewed by others
References
Blumberg, A.F. 1994. A primer for ECOM-si. Technical report of HydroQual. Mahwah, New Jersey.
Bowen, M.M., and W.R. Geyer. 2003. Salt transport and the time-dependent salt balance of partially stratified estuaries. Journal of Geophysical Research 108: C5. doi:10.1029/2001JC001231.
Chen, C.S., J.R. Zhu, E. Ralph, S.A. Green, J.W. Budd, and F.Y. Zhang. 2001. Prognostic modeling studies of the Keweenaw Current in Lake Superior, part I: formation and evolution. Journal of Physical Oceanography 31: 379–395.
Cudaback, C.N., and D.A. Jay. 2001. Tidal asymmetry in an estuarine pycnocline: 2. Transport. Journal of Geophysical Research 106(C2): 2639–2652.
Editorial Board for Marine Atlas. 1992. Ocean Atlas in Huanghai Sea and East China Sea (Hydrology). Bei**g: China Ocean Press.
Geyer, W.R., and D.M. Farmer. 1989. Tide-induced variation of the dynamics of a salt-wedge estuary. Journal of Physical Oceanography 28: 1060–1072.
Gong, W.P., and J. Shen. 2011. The response of saltwater intrusion to changes in river discharge and tidal mixing during the dry season in the Modaomen Estuary, China. Continental Shelf Research 31: 769–788.
Henriksen, H.J., L. Troldorg, P. Nyegaard, T.O. Sonnenborg, J.C. Refsgaard, and B. Madsen. 2003. Methodology for construction, calibration and validation of a national hydrological model for Denmark. Journal of Hydrology 280: 52–71.
Kantha, L.H., and C.A. Clayson. 1994. An improved mixed layer model for geophysical applications. Journal of Geophysical Research 99(C12): 25235–25266.
Kong, Y.Z., S.L. He, P.X. Ding, and K.L. Hu. 2004. Characteristics of temporal and spatial variation of salinity and their indicating significance in the Changjiang Estuary. Acta Oceanologica Sinica 26(4): 9–18 (in Chinese with English Abstract).
Li, L., J.R. Zhu, H. Wu, and B. Wang. 2010. A numerical study on water diversion ratio of the Changjiang (Yangtze) estuary in dry season. Chinese Journal of Oceanology and Limnology 28(3): 700–712.
Li, L., J.R. Zhu, and H. Wu. 2012. Impacts of wind stress on saltwater intrusion in the Yangtze Estuary. Science China Earth Science 55(7): 1178–1192.
Li, M.X., X.M. Liu, X.Y. Fu, A.P. Su, and L.T. Kong. 2009. Demonstration for the size of pump and sluice used in the water intake of Qingcaosha Reservoir. Water and Wastewater Engineering 35(2): 50–54 (in Chinese).
Mao, Z.C., H.T. Shen, and C.Y. **ao. 2001. Saltwater intrusion patterns in the Qingcaosha area Changjiang River Estuary. Oceanologia Et Liminologia Sinica 32(1): 58–66 (in Chinese with English Abstract).
Mao, Z.C., X.Y. Wu, C.Q. Zhao, and J.Q. Guo. 2008. Evolution of the upper reach of mouth bars in the North Channel of the Changjiang Estuary. Journal of Sediment Research 2: 41–46 (in Chinese with English Abstract).
Mellor, G.L., and T. Yamada. 1982. Development of a turbulence closure model for geophysical fluid problems. Reviews of Geophysics and Space Physics 20: 851–875.
Murphy, A.H. 1988. Skill scores based on the mean square error and their relationships to the correlation coefficient. Monthly Weather Review 116(12): 2417–2424.
Nepf, H.M., and W.R. Geyer. 1996. Intratidal variations in stratification and mixing in the Hudson estuary. Journal of Geophysical Research 101(C5): 12079–12086.
Qiu, C., J.R. Zhu, and Y.L. Gu. 2012. Impact of seasonal tide variation on saltwater intrusion in the Changjiang River estuary. Chinese Journal of Oceanology and Limnology 30(2): 342–351.
Ralston, D.K., W.R. Geyer, and J.A. Lerczak. 2010. Structure, variability, and salt flux in a strongly forced salt wedge estuary. Journal of Geophysical Research 115, C06005. doi:10.1029/2009JC005806.
Riedlinger, S.K., and G.A. Jacobs. 2000. Study of the dynamics of wind-driven transports into the Yellow Sea during winter. Journal of Geophysical Research 105(C12): 28695–28708.
Shen, H.T., Z.C. Mao, and J.R. Zhu. 2003. Saltwater intrusion in the Changjiang Estuary. Bei**g: China Ocean Press (in Chinese with English Abstract).
Uncles, R.J., and M.B. Jordan. 1979. Residual fluxes of water and salt at two stations in the Severn Estuary. Estuarine, Coastal and Shelf Science 9: 287–302.
Uncles, R.J. 2002. Estuarine physical processes research: some recent studies and progress. Estuarine, Coastal and Shelf Science 55: 829–856.
Wang, B., J.R. Zhu, H. Wu, F.J. Yu, and X.J. Song. 2012. Dynamics of saltwater intrusion in the Modaomen Waterway of the Pearl River Estuary. Science China Earth Science 55(11): 1901–1918.
Wu, H. 2006. Saltwater intrusion in the Changjiang Estuary—impact of saltwater spilling over, Deep Waterway Project and winter monsoon. Ph. D. thesis, East China Normal University, China.
Wu, H., J.R. Zhu, B.R. Chen, and Y.Z. Chen. 2006. Quantitative relationship of runoff and tide to saltwater spilling over from the North Branch in the Changjiang Estuary: a numerical study. Estuarine, Coastal and Shelf Science 69: 125–132.
Wu, H., and J.R. Zhu. 2010. Advection scheme with 3rd high-order spatial interpolation at the middle temporal level and its application to saltwater intrusion in the Changjiang Estuary. Ocean Modelling 33: 33–51.
Wu, H., J.R. Zhu, and B.H. Choi. 2010. Links between saltwater intrusion and subtidal circulation in the Changjiang Estuary: a model-guided study. Continental Shelf Research 30: 1891–1905.
Xu, K., J.R. Zhu, and Y.L. Gu. 2012. Impact of the eastern water diversion from the south to the north project on the saltwater intrusion in the Changjiang Estuary in China. Acta Oceanologica Sinica 31(3): 47–58.
Xue, P.F., C.S. Chen, P.X. Ding, R.C. Beardsley, H.C. Lin, J.Z. Ge, and Y.Z. Kong. 2009. Saltwater intrusion into the Changjiang River: a model-guided mechanism study. Journal of Geophysical Research 114, C02006. doi:10.1029/2008JC004831.
Zheng, L.Y., C.S. Chen, and H.D. Liu. 2003. A modeling study of the Satilla River Estuary. Georgia. I: flood-drying process and water exchange over the salt marsh-estuary-shelf complex. Estuaries 26(3): 651–669.
Zhu, J.R. 2003. Ocean numerical calculation method and numerical model. Bei**g: China Ocean Press (in Chinese with English Abstract).
Zhu, J.R., P.X. Ding, L.Q. Zhang, H. Wu, and H.J. Cao. 2006. Influence of the deep waterway project on the Changjiang Estuary. In The environment in Asia Pacific harbours, ed. E. Wolanski, 79–92. Netherlands: Springer.
Acknowledgments
This work was supported by the “Creative Research Group” of Natural Science Foundation of China (41021064), National Basic Scientific Research Program of Global Change (2010CB951201), National Natural Science Foundation of China (41176071), and Open Research Fund of State Key Laboratory of Estuarine and Coastal Research (SKLEC-KF201312). We thank the anonymous reviewers for their constructive suggestions.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by Carl T. Friedrichs
Rights and permissions
About this article
Cite this article
Li, L., Zhu, J., Wu, H. et al. Lateral Saltwater Intrusion in the North Channel of the Changjiang Estuary. Estuaries and Coasts 37, 36–55 (2014). https://doi.org/10.1007/s12237-013-9669-1
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12237-013-9669-1