Thin-Layer Gravity Current with Implications for Desalination Brine Disposal
Publication: Journal of Hydraulic Engineering
Volume 137, Issue 3
Abstract
Measurements of stratification and dissolved oxygen (DO) illustrate a hypersaline gravity current with salt loads similar to a desalination plant brine discharge. Over a 48-h sampling period in August 2005, alternating cycles of high- and low-temperature hypersaline water were observed along the bottom of Corpus Christi Bay in Texas, coincident with low benthic DO and tidal flushing from an adjacent smaller bay. The gravity current underflow was typically less than 10% of the overall water depth. Strong salinity gradients prevented wind-mixing of the entire water column. Hypoxic and near-hypoxic conditions were associated with limited DO replenishment from the ambient water. High DO levels in the underflow source water did not deter the development of offshore benthic hypoxia. A quasi-Lagrangian analysis is used to evaluate the relationship between ambient mixing and lateral mixing within the underflow. The analysis is further applied to estimating DO demand rates in the hypersaline plume. Mixing between the ambient water and the underflow predominately occurs over the sloping bay boundary. Once the gravity current reaches the flatter section of the bay, mixing is substantially reduced and DO is progressively depleted at the bottom. The transit time of the underflow (i.e., residence time or isolation time for water near the bottom) and wind-mixing energy appear to be key factors governing stratification persistence and potential hypoxia development. The observations and analyses provide insight into possible fate, impacts, and open questions associated with similarly scaled salt loadings from a desalination plant into a shallow bay.
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Acknowledgments
Funding for this project was provided by the U.S. Army Corps of Engineers (Texas Water Allocation Assessment grant USACE2001-999-015 to TWDB), the Texas Advanced Technology Program (UNSPECIFIED003658-0162-2003 to Hodges), the Texas Water Development Board (UNSPECIFIED2005-001-059 to Hodges), the National Science Foundation (NSFCBET 0610034 to Hodges), and a National Science Foundation Graduate Research Fellowship (to Kulis). Equipment and boats were provided by the UT Center for Research in Water Resources and TWDB. The authors acknowledge the invaluable assistance of TWDB personnel Carla Guthrie and Holly Weyant, along with UT students Cedric David, Shipeng Fu, John Middleton, Terry Palmer, and Jessica Watts for the summer 2005 field program. Data analysis by undergraduate research assistant Lauren Nance and REU student Andrew Brouwer provided insights used in this work. The authors are grateful to Prof. Paul Montagna of Texas A&M Corpus Christi for insights into hypoxic events and the use of his data in developing our research program.
References
Applebaum, S., Montagna, P., and Ritter, C. (2005). “Status and trends of dissolved oxygen in Corpus Christi Bay, Texas, USA.” Environ. Monit. Assess., 107(1-3), 297–311.
Benjamin, T. B. (1968). “Gravity currents and related phenomena.” J. Fluid Mech., 31, 209–248.
Bo Pedersen, F. B. (1986). Environmental hydraulics: Stratified flows, Springer-Verlag, Berlin.
Borsuk, M. E., Stow, C. A., Luettich, R. A., Paerl, H. W., and Pinckney, J. L. (2001). “Modelling oxygen dynamics in an intermittently stratified estuary: Estimation of process rates using field data.” Estuarine Coastal Shelf Sci., 52(1), 33–49.
Brouwer, A. F., Kulis, P. S., and Hodges, B. R. (2007). “Why can’t they breathe? Wind controlled hypoxia and stratification in Corpus Christi Bay.” Univ. of Texas at Austin, Environmental Science Institute NSF Research Experience for Undergraduates Poster Session, Austin, TX.
Carstensen, J., Henriksen, P., and Heiskanen, A. S. (2007). “Summer algal blooms in shallow estuaries: Definition, mechanisms, and link to eutrophication.” Limnol. Oceanogr., 52(1), 370–384.
Cuthbertson, A. J. S., Davies, P. A., and Guo, Y. K. (2006). “Model study of the influence of submerged tidal barriers on estuarine mixing and exchange processes.” J. Hydraul. Eng., 132(10), 1033–1043.
Dallimore, C. J., Imberger, J., and Ishikawa, T. (2001). “Entrainment and turbulence in saline underflow in Lake Ogawara.” J. Hydraul. Eng., 127(11), 937–948.
Engle, V. D., Summers, J. K., and Macauley, J. M. (1999). “Dissolved oxygen conditions in northern Gulf of Mexico estuaries.” Environ. Monit. Assess., 57(1), 1–20.
Fernandez, R. L., and Imberger, J. (2008). “Relative buoyancy dominates thermal-like flow interaction along an incline.” J. Hydraul. Eng., 134(5), 636–643.
Fischer, H. B., List, E. J., Koh, R. C. Y., Imberger, J., and Brooks, N. H. (1979). Mixing in inland and coastal waters. Academic Press, San Diego.
Hagy, J. D., and Murrell, M. C. (2007). “Susceptibility of a northern Gulf of Mexico estuary to hypoxia: An analysis using box models.” Estuarine Coastal Shelf Sci., 74(1-2), 239–253.
Hearn, C. J. (1998). “Application of the Stommel model to shallow Mediterranean estuaries and their characterization.” J. Geophys. Res. Oceans, 103(C5), 10391–10404.
Hearn, C. J., and Robson, B. J. (2000). “Modelling a bottom diurnal boundary layer and its control of massive alga blooms in an estuary.” Appl. Math. Model., 24(11), 843–859.
Hearn, C. J., and Robson, B. J. (2001). “Inter-annual variability of bottom hypoxia in shallow Mediterranean estuaries.” Estuarine Coastal Shelf Sci., 52(5), 643–657.
Hearn, C. J., and Robson, B. J. (2002). “On the effects of wind and tides on the hydrodynamics of a shallow Mediterranean estuary.” Cont. Shelf Res., 22(18-19), 2655–2672.
Hodges, B. R., and Furnans, J. E. (2007), “Thin-layer gravity currents in a shallow estuary.” Proc., 18th ASCE Engineering Mechanics Division Conf. (CD-ROM), Virginia Polytechnic Inst. and State Univ., Blacksburg, VA.
Hodges, B. R., Imberger, J., Saggio, A., and Winters, K. B. (2000). “Modeling basin-scale internal waves in a stratified lake.” Limnol. Oceanog., 45(7), 1603–1620.
Huppert, H. E. (2006). “Gravity currents: A personal perspective.” J. Fluid Mech., 554, 299–322.
Ivey, G. N., and Imberger, J. (1991). “On the nature of turbulence in a stratified fluid. 1. The energetics of mixing.” J. Phys. Oceanogr., 21(5), 650–658.
Kneller, B., and Buckee, C. (2000). “The structure and fluid mechanics of turbidity currents: a review of some recent studies and their geological implications.” Sedimentology, 47, 62–94.
Kulis, P. S., and Hodges, B. R. (2005). “Improved techniques for gravity current modeling.” Proc., Mechanics and Materials Conf. (CD-ROM), Louisiana State Univ., Baton Rouge.
Kulis, P. S., and Hodges, B. R. (2006). “Modeling gravity currents in shallow bays using a sigma coordinate model,” Proc., 7th Int. Conf. on Hydroscience and Engineering (electronic proc.), 11–13, Drexel Univ., Philadelphia, 〈http://hdl.handle.net/1860/1458〉.
Largier, J. L., Hollibaugh, J. T., and Smith, S. V. (1997). “Seasonally hypersaline estuaries in Mediterranean-climate regions.” Estuarine Coastal Shelf Sci., 45(6), 789–797.
Lennon, G. W., et al. (1987). “Gravity currents and the release of salt from an inverse estuary.” Nature (London), 327(6124), 695–697.
Lin, J., Xie, L., Pietrafesa, L. J., Shen, J., Mallin, M. A., and Durako, M. J. (2006). “Dissolved oxygen stratification in two micro-tidal partially-mixed estuaries.” Estuarine Coastal Shelf Sci., 70(3), 423–437.
Marino, B. M., Thomas, L. P., and. Linden, P. F. (2005). “The front condition for gravity currents.” J. Fluid Mech., 536, 49–78.
Mason, R. P., Lawson, N. M., Lawrence, A. L., Leaner, J. J., Lee, J. G., and Sheu, G. R. (1999). “Mercury in the Chesapeake Bay.” Mar. Chem., 65(1-2), 77–96.
Melrose, D. C., Oviatt, C. A., and Berman, M. S. (2007). “Hypoxic events in Narragansett Bay, Rhode Island, during the summer of 2001.” Estuaries Coasts, 30(1), 47–53.
Minsker, B., et al. (2007) “Integrating sensor data and informatics to improve understanding of hypoxia in the WATERS network testbed at Corpus Christi Bay, Texas.” EOS Transactions of the American Geophysical Union, Fall Meeting, San Francisco, 10–14.
Montagna, P. A., and Kalke, R. D. (1992). “The effect of fresh-water inflow on meiofaunal and macrofaunal populations in the Guadalupe and Nueces Estuaries, Texas.” Estuaries, 15(3), 307–326.
Montagna, P. A., and Ritter, C. (2006). “Direct and indirect effects of hypoxia on benthos in Corpus Christi Bay, Texas, USA.” J. Exp. Mar. Biol. Ecol., 330(1), 119–131.
Nielsen, M. H., Rasmussen, B., and Gertz, F. (2005). “A simple model for water level and stratification in Ringkobing Fjord, a shallow, artificial estuary.” Estuarine Coastal Shelf Sci., 63(1-2), 235–248.
Nuttle, W. K., Fourqurean, J. W., Cosby, B. J., Zieman, J. C., and Robblee, M. B. (2000). “Influence of net freshwater supply on salinity in Florida Bay.” Water Resour. Res., 36(7), 1805–1822.
Ojo, T. O., Bonner, J. S., and Page, C. A. (2006). “Observations of shear-augmented diffusion processes and evaluation of effective diffusivity from current measurments in Corpus Christi Bay.” Conti. Shelf Res., 26, 788–803.
Park, K., Kim, C. K., and Schroeder, W. W. (2007). “Temporal variability in summertime bottom hypoxia in shallow areas of Mobile Bay, Alabama.” Estuaries Coasts, 30(1), 54–65.
Ritter, C., and Montagna, P. A. (1999). “Seasonal hypoxia and models of benthic response in a Texas Bay.” Estuaries, 22(1), 7–20.
Russell, M. J., and Montagna, P. A. (2007). “Spatial and temporal variability and drivers of net ecosystem metabolism in western Gulf of Mexico estuaries.” Estuaries Coasts, 30(1), 137–153.
San Antonio Water System (SAWS). (2007). “LCRA-SAWS Water Project 2006 Project Viability Assessment.” San Antonio Water Authority, 〈http://www.saws.org/our_water/waterresources/projects/lcra/lcra_downloads.shtml〉 (June 2008).
Sell, K. S., and Morse, J. W. (2006). “Dissolved Fe2+ and ΣH2S behavior in sediments seasonally overlain by hypoxic-to-anoxic waters as determined by CSV microelectrodes.” Aquat. Geochem., 12(2), 179–198.
Shin, J. O., Dalziel, S. B., and Linden, P. A. (2004). “Gravity currents produced by lock exchange.” J. Fluid Mech., 521, 1–34.
Simpson, J. E. (1997). Gravity currents in the environment and the laboratory. Cambridge University Press, Cambridge, UK, 244.
Spigel, R. H., Imberger, J., and Rayner, K. N. (1986). “Modeling the diurnal mixed layer.” Limnol. Oceanog., 31(3), 533–556.
Texas Water Development Board (TWDB). (2002). “Desalination—A status report,” Water for Texas Quarterly, 12(2), 〈http://www.twdb.state.tx.us/publications/newsletters/WaterforTexas/WFTSpring02/art2Desalination.htm〉 (April 2005).
Thorpe, S. A. (1973). “Turbulence in stratified fluids: A review of laboratory experiments.” Bound.-Lay. Meteorol., 5, 95–119.
To, E. S. C., and Maidment, D. R. (2009). “Hypoxia modeling in Corpus Christi Bay using a hydrologic information system.,” Online Rep. 2009-02, Center for Research in Water Resources, Univ. of Texas at Austin, 183, 〈http://www.crwr.utexas.edu/reports/2009/rpt09-2.shtml〉.
Turner, J. S. (1998). “Stratification and circulation produced by heating and evaporation on a shelf.” J. Mar. Res., 56(4), 885–904.
Verity, P. G., Alber, M., and Bricker, S. B. (2006). “Development of hypoxia in well-mixed subtropical estuaries in the southeastern USA.” Estuaries Coasts, 29(4), 665–673.
Ward, G. H. (1997). “Processes and trends of circulation within the Corpus Christi Bay national estuary program study area,”CCBNEP-21, Texas Natural Resource Conservation Commission, Austin, TX.
Wei, H., He, Y. C., Li, Q. J., Liu, Z. Y., and Wang, H. T. (2007). “Summer hypoxia adjacent to the Changjiang Estuary.” J. Marine Syst., 67(3-4), 292–303.
Wells, M. G., and Wettlaufer, J. S. (2005). “Two-dimensional density currents in a confined basin.” Geophys. Astrophys. Fluid Dyn., 99(3), 199–218.
Wells, M. G., and Wettlaufer, J. S. (2007). “The long-term circulation driven by density currents in a two-layer stratified basin.” J. Fluid Mech., 572, 37–58.
Whitfield, A. K., Taylor, R. H., Fox, C., and Cyrus, D. P. (2006). “Fishes and salinities in the St. Lucia estuarine system—a review.” Rev. Fish Biol. Fish., 16(1), 1–20.
Winant, C. D., and de Velasco, G. G. (2003). “Tidal dynamics and residual circulation in a well-mixed inverse estuary.” J. Phys. Oceanogr., 33(7), 1365–1379.
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Published In
Journal of Hydraulic Engineering
Volume 137 • Issue 3 • March 2011
Pages: 356 - 371
Copyright
© 2011 American Society of Civil Engineers.
History
Received: Aug 9, 2008
Accepted: Aug 25, 2010
Published online: Aug 27, 2010
Published in print: Mar 1, 2011
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