SpringerLink
Log in

The Effects of Wind, Runoff and Tides on Salinity in a Strongly Tidal Sub-estuary

  • Published:
Estuaries and Coasts Aims and scope Submit manuscript

Abstract

Measurements over an annual cycle of longitudinal and vertical salinity distributions in a small sub-estuary, the Tavy Estuary, UK, are used to illustrate the dependence of salt intrusion and stratification on environmental variables. The interpretations are aided by vertical profiling and near-bed data recorded in the main channel and on the mudflats. Generally, high water (HW) salt intrusion at the bed is close to the tidal limit and is dominated by runoff and winds, with decreasing salt intrusion associated with increasing runoff and increasing up-estuary winds (or vice versa). Tidal effects are not statistically significant because of two compensating processes: the long tidal excursion, which is comparable with the sub-estuary length for all but the smallest neap tides, and the enhanced, near-bed, buoyancy-driven salt transport that occurs at small neap tides close to the limit of saline intrusion. The effect of wind on HW surface salt intrusion in the main channel is not statistically significant, partly because it is obscured by the opposing local and estuary-wide effects of an up-estuary or down-estuary wind stress. These processes are investigated using a simple tidal model that incorporates lateral, channel–mudflat bathymetry and reproduces, approximately, observed channel and mudflat velocities. Surface salinity at HW increases with tidal range because of enhanced spring-tide vertical mixing—a process that also reduces salinity stratification. Stratification increases with runoff because of increased buoyancy inputs and decreases with up-estuary winds because of reduced near-bed salt intrusion. Stratification and plume formation are interpreted in terms of the bulk and estuarine Richardson Numbers, and processes at the confluence of the sub-estuary and main estuary are described.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7

Similar content being viewed by others

References

  • ATT. 2007. Admiralty tide tables, volume 1, 358. Taunton, UK: UK Hydrographic Office.

    Google Scholar 

  • Barlow, J.P. 1956. Effect of wind on salinity distribution in an estuary. Journal of Marine Research 15: 193–203.

    Google Scholar 

  • Barne, J.H., Robson, C.F., Kaznowska, S.S., Doody, J.P., Davidson, N.C., and A.L. Buck (eds.) 1996. Coasts and seas of the United Kingdom. Region 10 Southwest England: Seaton to the Roseland Peninsula. Peterborough, Joint Nature Conservation Committee (Coastal Directories Series.)

  • Becker, M.L., R.A. Luettich Jr., and M.A. Mallin. 2010. Hydrodynamic behavior of the Cape Fear River and estuarine system: A synthesis and observational investigation of discharge–salinity intrusion relationships. Estuarine, Coastal and Shelf Science 88: 407–418.

    Article  CAS  Google Scholar 

  • Blumberg, A.F., and D.M. Goodrich. 1990. Modeling of wind-induced destratification in Chesapeake Bay. Estuaries 13: 236–249.

    Article  Google Scholar 

  • Bowen, M.M., and W.R. Geyer. 2003. Salt transport and the time-dependent salt balance of a partially stratified estuary. Journal of Geophysical Research 108(C5): 3158. doi:10.1029/2001JC001231.

    Article  Google Scholar 

  • Castaing, P., and A. Guilcher. 1995. Geomorphology and sedimentology of rias. In Geomorphology and sedimentology of estuaries. Developments in sedimentology 53, ed. G.M.E. Perillo, 69–111. Oxford: Elsevier.

    Chapter  Google Scholar 

  • Chanson, H. 2008. Field observations in a small subtropical estuary during and after a rainstorm event. Estuarine, Coastal and Shelf Science 80: 114–120.

    Article  Google Scholar 

  • Chen, S.-N., and L.P. Sanford. 2009. Axial wind effects on stratification and longitudinal salt transport in an idealized, partially mixed estuary. Journal of Physical Oceanography 39: 1905–1920.

    Article  Google Scholar 

  • Dellapenna, T.M., S.A. Kuehl, and L.C. Schaffner. 1998. Sea-bed mixing and particle residence times in biologically and physically dominated estuarine systems: a comparison of lower Chesapeake Bay and the York River subestuary. Estuarine, Coastal and Shelf Science 46: 777–795.

    Article  Google Scholar 

  • Dyer, K.R. 1986. Estuarine and coastal sediment dynamics, 342. Chichester: John Wiley.

    Google Scholar 

  • Dyer, K.R. 1997. Estuaries: a physical introduction, 195. Chichester: John Wiley.

    Google Scholar 

  • Dyer, K.R., and A.L. New. 1986. Intermittency in estuarine mixing. In Estuarine variability, Academic Press, ed. D.A. Wolfe, 321–339. Florida, USA: Orlando.

    Google Scholar 

  • Dyer, K.R., and K. Ramamoorthy. 1969. Salinity and water circulation in the Vellar estuary. Limnology and Oceanography 14: 4–15.

    Article  Google Scholar 

  • Fischer, H.B., E.J. List, R.C.Y. Koh, J. Imberger, and N.H. Brooks. 1979. Mixing in inland and coastal waters, 483. N.Y.: Academic.

    Google Scholar 

  • Geyer, W.R. 1997. Influence of wind on dynamics and flushing of shallow estuaries. Estuarine, Coastal and Shelf Science 44: 713–722.

    Article  Google Scholar 

  • Goodrich, D.M., W.C. Boicourt, P. Hamilton, and D.W. Pritchard. 1987. Wind-induced destratification in Chesapeake Bay. Journal of Physical Oceanography 17: 2232–2240.

    Article  Google Scholar 

  • Goudie, A.S., and R.A.M. Gardner. 1996. Discovering landscape in England and Wales, 177. London: Chapman and Hall. Second Reprint.

    Google Scholar 

  • Hansen, D.V., and M.R. Rattray. 1965. Gravitational circulation in straits and estuaries. Journal of Marine Research 23: 104–122.

    Google Scholar 

  • Haywood, D., C.S. Welch, and L.W. Hass. 1982. York River destratification: an estuary-sub-estuary interaction. Science 216: 1413–1414.

    Article  Google Scholar 

  • Heidel, S.G. 1956. The progressive lag of sediment concentration with flood waves. Transactions of the American Geophysical Union 37: 56–66.

    Google Scholar 

  • Huzzey, L.M. 1988. The lateral density distribution in a partially mixed estuary. Estuarine, Coastal and Shelf Science 26: 351–358.

    Article  Google Scholar 

  • Huzzey, L.M., and J. Brubaker. 1988. The formation of longitudinal fronts in a coastal plain estuary. Journal of Geophysical Research 93: C2. doi:10.1029/JC093iC02p01329.

    Article  Google Scholar 

  • IH. 2003. Hydrological data UK: hydrometric register and statistics 1996–2000. Prepared by the Institute of Hydrology and the British Geological Survey and published by the Institute of Hydrology, 208. Wallingford: Oxon OX10 8BB.

    Google Scholar 

  • Jago, C.F., A.K. Ishak, S.E. Jones, and M.R.G. Goff. 2006. An ephemeral turbidity maximum generated by resuspension of organic-rich matter in a macrotidal estuary, SW Wales. Estuaries and Coasts 29: 197–208.

    Article  Google Scholar 

  • Janzen, C.D., and K.-C. Wong. 2002. Wind-forced dynamics at the estuary-shelf interface of a large coastal plain estuary. Journal of Geophysical Research 107(C10): 3138. doi:10.1029/2001JC000959.

    Article  Google Scholar 

  • Jolliffe, I.T. 2002. Principal component analysis, 2nd ed, 520. Springer, New York: Springer Series in Statistics.

    Google Scholar 

  • Keulegan, G.H. 1966. The mechanism of an arrested salinity wedge, p. 546–574. In Estuary and coastline hydrodynamics, Engineering Societies Monograph, ed. A.T. Ippen, 744. New York, NY: McGraw-Hill Book Company.

    Google Scholar 

  • Largier, J.L., J.T. Hollibaugh, and S.V. Smith. 1997. Seasonally hypersaline estuaries in mediterranean-climate regions. Estuarine, Coastal and Shelf Science 45: 789–797.

    Article  Google Scholar 

  • Lewis, R. 1997. Dispersion in estuaries and coastal waters, 312. Chichester: John Wiley.

    Google Scholar 

  • Li, M., L. Zhong, W.C. Boicourt, S. Zhang, and D.-L. Zhang. 2007. Hurricane-induced destratification and restratification in a partially-mixed estuary. Journal of Marine Research 65: 169–192.

    Google Scholar 

  • Linden, P.F., and J.E. Simpson. 1986. Gravity driven flows in a turbulent fluid. Journal of Fluid Mechanics 172: 481–497.

    Article  Google Scholar 

  • Linden, P.F., and J.E. Simpson. 1988. Modulated mixing and frontogenesis in shallow seas and estuaries. Continental Shelf Research 8: 1107–1127.

    Article  Google Scholar 

  • MacCready, P. 1999. Estuarine adjustment to changes in river flow and tidal mixing. Journal of Physical Oceanography 29: 708–726.

    Article  Google Scholar 

  • Mitchell, S.B., and H.M. Burgess. 2004. Effect on estuarine fine-sediment transport of intermittent pump discharge at Pagham Harbour, West Sussex. Water Environment Journal 18: 39–43.

    Article  Google Scholar 

  • Mitchell, S.B., H.M. Burgess, and D.J. Pope. 2006. Stratification and fine sediment transport mechanisms in a semi-enclosed tidal lagoon (Pagham Harbour, West Sussex). Water Environment Journal 20: 248–255.

    Article  Google Scholar 

  • Mitchell, S.B., H.M. Burgess, D.J. Pope, and A. Theodoridou. 2008. Field studies of velocity, salinity and suspended solids concentration in a shallow tidal channel near tidal flap gates. Estuarine, Coastal and Shelf Science 78: 385–395.

    Article  Google Scholar 

  • Nichols, M.M. 1994. Response of estuaries to storms in the Chesapeake Bay region: summary. In Changes in fluxes in estuaries: implications from science to management, ed. K.R. Dyer and R.J. Orth, 67–70. Fredensborg, Denmark: Olsen and Olsen.

    Google Scholar 

  • North, E.W., S.-Y. Chao, L.P. Sanford, and R.R. Hood. 2004. The influence of wind and river pulses on an estuarine turbidity maximum: numerical studies and field observations in Chesapeake Bay. Estuaries 27: 132–146.

    Article  Google Scholar 

  • Nunes Vaz, R.A., and G.W. Lennon. 1991. Modulation of estuarine stratification and mass flux at tidal frequencies. In Tidal hydrodynamics, ed. B.B. Parker, 505–520. New York: John Wiley & Sons.

    Google Scholar 

  • Nunes Vaz, R.A., G.W. Lennon, and J.R. de Silva Samarasinghe. 1989. The negative role of turbulence in estuarine mass transport. Estuarine, Coastal and Shelf Science 28: 361–377.

    Article  CAS  Google Scholar 

  • O’Callaghan, J., C. Pattiaratchi, and D. Hamilton. 2007. The response of circulation and salinity in a micro-tidal estuary to sub-tidal oscillations in coastal sea surface elevation. Continental Shelf Research 27: 1947–1965.

    Article  Google Scholar 

  • Officer, C.B. 1976. Physical oceanography of estuaries (and associated coastal waters), 465. New York: John Wiley.

    Google Scholar 

  • Perillo, G.E.M. 1995. Definitions and geomorphologic classifications of estuaries. In Geomorphology and sedimentology of estuaries. Developments in Sedimentology 53, ed. G.M.E. Perillo, 17–47. Oxford: Elsevier.

    Chapter  Google Scholar 

  • Pope, N.D., J. Widdows, and M.D. Brinsley. 2006. Estimation of bed shear stress using the turbulent kinetic energy approach - a comparison of annular flume and field data. Continental Shelf Research 26: 959–970.

    Article  Google Scholar 

  • Prandle, D. 2004. Saline intrusion in partially mixed estuaries. Estuarine, Coastal and Shelf Science 59: 385–397.

    Article  CAS  Google Scholar 

  • Ralston, D.K., and M.T. Stacey. 2005a. Stratification and turbulence in subtidal channels through intertidal mudflats. Journal of Geophysical Research 110: C08009. doi:10.1029/2004JC002650, 1-16.

    Article  Google Scholar 

  • Ralston, D.K., and M.T. Stacey. 2005b. Longitudinal dispersion and lateral circulation in the intertidal zone. Journal of Geophysical Research 110: C07015. doi:10.1029/2005JC002888, 1-17.

    Article  Google Scholar 

  • 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.

    Article  Google Scholar 

  • Reid, I., and L.E. Frostick. 1994. Fluvial sediment transport and deposition. In Sediment transport and depositional processes, ed. K. Pye, 397. Oxford, UK: Blackwell Scientific Publications. 89–156.

    Google Scholar 

  • Samarasinghe, J.R. de Silva, and G.W. Lennon. 1987. Hypersalinity, flushing and transient salt-wedges in a tidal gulf—an inverse estuary. Estuarine, Coastal and Shelf Science 24: 483–498.

    Article  CAS  Google Scholar 

  • Scully, M.E., C. Friedrichs, and J. Brubaker. 2005. Control of estuarine stratification and mixing by wind-induced straining of the estuarine density field. Estuaries 28: 321–326.

    Article  Google Scholar 

  • Simpson, J.H. 1981. The shelf sea fronts: implications of their existence and behaviour. Philosophical Transactions of the Royal Society of London A302: 531–546.

    Google Scholar 

  • Simpson, J.H., and R.A. Nunes. 1981. The tidal intrusion front: an estuarine convergence zone. Estuarine, Coastal and Shelf Science 13: 257–266.

    Article  Google Scholar 

  • Soulsby, R. 1997. Dynamics of marine sands: A manual for practical applications, 249. London: Thomas Telford.

    Google Scholar 

  • Uncles, R.J. 2002. Estuarine physical processes research: Some recent studies and progress. Estuarine, Coastal and Shelf Science 55: 829–856.

    Article  Google Scholar 

  • Uncles, R.J., and M.B. Jordan. 1979. Residual fluxes of water and salt at two stations in the Severn Estuary. Estuarine and Coastal Marine Science 9: 287–302.

    Article  Google Scholar 

  • Uncles, R.J., and R.E. Lewis. 2001. The transport of fresh water from river to coastal zone through a temperate estuary. Journal of Sea Research 46: 161–175.

    Article  Google Scholar 

  • Uncles, R.J., and J.A. Stephens. 1989. Distributions of suspended sediment at high water in a macrotidal estuary. Journal of Geophysical Research 94(C10): 14395–14405.

    Article  Google Scholar 

  • Uncles, R.J., and J.A. Stephens. 1990. Computed and observed currents, elevations and salinity in a branching estuary. Estuaries 13: 133–144.

    Article  Google Scholar 

  • Uncles, R.J., and J.A. Stephens. 1993a. The freshwater-saltwater interface and its relationship to the turbidity maximum in the Tamar Estuary, UK. Estuaries 16: 126–141.

    Article  Google Scholar 

  • Uncles, R.J., and J.A. Stephens. 1993b. Nature of the turbidity maximum in the Tamar Estuary, UK. Estuarine, Coastal and Shelf Science 36: 413–431.

    Article  Google Scholar 

  • Uncles, R.J., and J.A. Stephens. 2000. Observations of currents, salinity, turbidity and intertidal mudflat properties in the Tavy Estuary, UK. Continental Shelf Research 20: 1531–1549.

    Article  Google Scholar 

  • Uncles, R.J., and J.A. Stephens. 2010. Turbidity and sediment transport in a muddy sub-estuary. Estuarine, Coastal and Shelf Science 87: 213–224.

    Google Scholar 

  • Uncles, R.J., R.C.A. Elliott, and S.A. Weston. 1985. Observed fluxes of water, salt and suspended sediment in a partly mixed estuary. Estuarine, Coastal and Shelf Science 20: 147–167.

    Article  CAS  Google Scholar 

  • Uncles, R.J., R.C.A. Elliott, and S.A. Weston. 1986. Observed and computed lateral circulation patterns in a partly mixed estuary. Estuarine, Coastal and Shelf Science 22: 439–457.

    Article  Google Scholar 

  • Uncles, R.J., J.A. Stephens, R.H. Bruce, C.D. Barrett, and N.J. Bloomer. 1989. Observations of temporal variability in a partly mixed estuary using a new instrument package. In Developments in estuarine and coastal study techniques, ed. J. McManus and M. Elliott, 158. Denmark: Olsen and Olsen. 151–157.

    Google Scholar 

  • Valle-Levinson, A., J.A. Delgado, and L.P. Atkinson. 2001. Reversing water exchange patterns at the entrance to a semiarid coastal lagoon. Estuarine, Coastal and Shelf Science 53: 825–838.

    Article  Google Scholar 

  • Valle-Levinson, A., G. Gutierrez de Velasco, A. Trasviña, A. Souza, R. Durazo, and A. Mehta. 2009. Residual exchange flows in subtropical estuaries. Estuaries and Coasts 32: 54–67.

    Article  Google Scholar 

  • Van de Kreeke, J., and K. Robaczewska. 1989. Effect of wind on the vertical circulation and stratification in the Volkerak Estuary. Netherlands Journal of Sea Research 23: 239–253.

    Article  Google Scholar 

  • Vieira, M.E.C., and A.A. Bordalo. 2000. The Douro estuary (Portugal): a mesotidal salt wedge. Oceanologica Acta 23: 585–594.

    Article  Google Scholar 

  • Vijith, V., D. Sundar, and S.R. Shetye. 2009. Time-dependence of salinity in monsoonal estuaries. Estuarine, Coastal and Shelf Science 85: 601–608.

    Article  CAS  Google Scholar 

  • Wolanski, E. 1986. An evaporation-driven salinity maximum zone in Australian tropical estuaries. Estuarine, Coastal and Shelf Science 22: 415–424.

    Article  CAS  Google Scholar 

  • Wong, K.-C., and J.E. Moses-Hall. 1998. On the relative importance of the remote and local wind effects to the subtidal variability in a coastal plain estuary. Journal of Geophysical Research 103(C9): 18393–18404.

    Article  Google Scholar 

  • Xu, H., J. Lin, and D. Wang. 2008. Numerical study on salinity stratification in the Pamlico River Estuary. Estuarine, Coastal and Shelf Science 80: 74–84.

    Article  Google Scholar 

Download references

Acknowledgements

This work is a contribution to the UK’s Natural Environment Research Council (NERC) ‘Oceans 2025’ Programme. We are grateful to Ms. Tracy Woodrow, Mr. Norman Bowley and Mr. Ron Easton for their invaluable assistance and support during the fieldwork.

Author information

Authors and Affiliations

  1. Plymouth Marine Laboratory, Prospect Place, Plymouth, PL1 3DH, UK

    Reginald J. Uncles & John A. Stephens

Authors
  1. Reginald J. Uncles
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. John A. Stephens
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Reginald J. Uncles.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Uncles, R.J., Stephens, J.A. The Effects of Wind, Runoff and Tides on Salinity in a Strongly Tidal Sub-estuary. Estuaries and Coasts 34, 758–774 (2011). https://doi.org/10.1007/s12237-010-9365-3

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s12237-010-9365-3

Keywords

Search

Navigation