A Numerical Simulation of the Dispersion of Sediments Suspended by Estuarine Dredging Operations

  • Donald F. Cundy
  • W. F. Bohlen
Part of the Marine Science book series (MR, volume 11)

Abstract

A predictive numerical model designed to simulate the dispersion of sediments suspended by estuarine clam-shell dredging operations is described. The model evaluates the downstream distribution of the column of materials introduced by each vertical pass of the dredge bucket using a modified conservation of mass approach in which a horizontal moment term is used to represent the spatial distribution of the suspended mass concentrations. Solution of the resultant equation in finite difference form provides a time history of the 0th to 4th moments of the dispersing mass introduced by each bucket pass. A representation of the sum total effect of these discrete injections forming the downstream plume is then developed through linear superposition. This scheme provides a description of the gross characteristics of the dispersing mass without requiring large amounts of computer time and storage.

Required inputs to the model include specification of the local mean velocity characteristics, sediment settling velocities and turbulent mass diffusion coefficients. Field data obtained under a variety of conditions are used to supply these inputs and to test the accuracy of the computational scheme.

Preliminary comparisons suggest that this model provides a reasonable analogue of observed field conditions. Accuracy appears to be primarily dependent on the specification of settling velocity and mass diffusivity representing second-order influences.

Keywords

Settling Velocity Suspended Material Open Channel Flow Clam Shell Finite Difference Form 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Ames, W. F., 1977. Numerical methods for partial differential equations. Academic Press, New York. 365 pps.Google Scholar
  2. Aris, R., 1956. On the dispersion of a solute in a fluid flowing through a tube. Proc. Roy. Soc. London, Vol. 235A:67–77.CrossRefGoogle Scholar
  3. Atesman, K. M., 1970. The dispersion of matter in turbulent shear flows. Unpubl. Ph.D. Thesis, University of Colorado at Fort Collins, 158 pps.Google Scholar
  4. Atesman, K. M., 1975. Point source dispersion in turbulent open channels. Proc. Amer. Soc. Civ. Eng., J. of Hyd. Div., Vol. 101, No. HY7: 789–799.Google Scholar
  5. Bohlen, W. F., D. F. Cundy and J. M. Tramontano, 1979. Suspended material distributions in the wake of estuarine channel dredging operation. Estuarine and Coastal Marine Science (in press).Google Scholar
  6. Bohlen, W. F., 1979. Factors governing the distribution of dredge-resuspended sediments. Proc. of Sixteenth Coastal Eng. Conf., Hamburg, Germany (in press).Google Scholar
  7. Chatwin, P. C, 1968. The dispersion of a puff of passive contaminant in the constant stress region. Quart. J. Roy. Met. Soc, London, Vol. 94:350–360.CrossRefGoogle Scholar
  8. Cundy, D. F., 1979. A finite difference model of the dispersion of dredge entrained sediments. MS Thesis, University of Connecticut, Storrs, Ct. (in preparation).Google Scholar
  9. Fischer, H. B., 1967. The mechanics of dispersion in natural streams. Proc. Amer. Soc. Civ. Eng., J. of Hyd. Div., Vol. 93, No. HY6: 187–216.Google Scholar
  10. Koh, R. C. Y. and Y. C. Chang, 1973. Mathematical model for barged ocean wastes. Prepared for the United States Environmental Protection Agency, National Environmental Research Center, Corvallis, Oregon, 178 pps + Apps.Google Scholar
  11. Orlob, G. T., 1959. Eddy diffusion in homogeneous turbulence. Proc. Amer. Soc. Civ. Eng.- J. of Hyd. Div., Vol. 85, No. HY9: 75–101.Google Scholar
  12. Sayre, W. W., 1968. Dispersion of mass in open-channel flow. Hydrology Papers, Colorado State University at Fort Collins, Colorado, No. 75, 73 pps.Google Scholar
  13. Sayre, W. W., 1969. Dispersion of silt particles in open channel flow. Proc. Amer. Soc. Civ. Eng., J. of Hyd. Div., Vol. 90, No. HY3: 1009–1038.Google Scholar
  14. Yotsukura, N. and M. B. Fiering, 1964. Numerical solution to dispersion equation. Amer. Soc. Civ. Eng., J. of Hyd. Div., Vol. 90, No. HY5:.83–104.Google Scholar

Copyright information

© Springer Science+Business Media New York 1980

Authors and Affiliations

  • Donald F. Cundy
    • 1
  • W. F. Bohlen
    • 1
  1. 1.Marine Sciences InstituteThe University of ConnecticutGrotonUSA

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