Chapter lll-2. Longshore Sediment TransportFigure lll-2-1. Impoundment of longshore sediment transport at Indian River Inlet, DelawareModes of sediment transport.Experimental measurementFigure III-2-2. Cross-shore distribution of the longshore sand transport rate measured with traps at Duck, North Carolina (Kraus, Gingerich, and Rosati 1989)Quantitative indicators of longshore transport magnitudeLongshore sediment transport estimation in the United StatesFigure III-2-3. Estimated annual net longshore transport rates and directions along the east coast of the United States based on data from Johnson (1956, 1957) and Komar (1976)Table lll-2-1. Longshore Transport Rates from U.S. Coasts (SPM 1984)1Energy flux method.DescriptionFigure lll-2-4. Field data relating IR and PRVariation of K with median grain size.Figure lll-2-5. Measured and predicted K coefficients using Bailard's (1984) equationFigure lll-2-6. Coefficient K versus median grain size D50 (del Valle, Medina, and Losada 1993)EXAMPLE PROBLEM III-2-1EXAMPLE PROBLEM III-2-1 (cont)EXAMPLE PROBLEM III-2-2EXAMPLE PROBLEM III-2-3EXAMPLE PROBLEM III-2-4Wave transformation procedure. Wave conditions.EXAMPLE PROBLEM III-2-5EXAMPLE PROBLEM III-2-5 (cont)EXAMPLE PROBLEM III-2-6Deviation from potential longshore sediment transport rates.Figure lll-2-7. Longshore transport definitionsFigure lll-2-8. Time plot of annual longshore energy flux factor at three east coast sites (after Douglass (1985))Figure III-2-9. Time plot of monthly longshore energy flux factor time series for 1956-1975 at three east coast sites (after Douglass (1985))Figure lll-2-10. Probability plot for monthly average Pls series (Walton and Douglass 1985)Figure lll-2-12. Autocorrelation of monthly Pls series (Walton and Douglass 1985)Figure lll-2-13. Autocorrelation of weekly average Pls series (Walton and Douglass 1985)Littoral drift roses.Figure lll-2-14. Azimuth of normal to shoreline at Ponte Vedra Beach, Florida (Walton 1972)Figure lll-2-15. Net and total littoral drift at Ponte Vedra Beach, Florida (Walton 1972)Figure lll-2-16. Ideal case of an unstable null point (Walton 1972)Figure lll-2-17. Instability-formed capes in Santa Rosa Sound (Walton 1972)Figure lll-2-18. Ideal case of a stable null point (Walton 1972)Figure III-2-19. Distribution of tracer density across the surf zone, 20 October 1961 Goleta Point, California, experiment (Ingle 1966)Figure III-2-20. Distribution of mean sediment concentration at 10 cm above the bed, relative to wave breakpoint (Kana 1978)Figure III-2-21. Cross-shore distribution of longshore sediment transport as measured by Bodge and Dean (Bodge 1986, Bodge and Dean 1987a, 1987b) at Duck, North Carolina, and in the laboratoryFigure III-2-21. Cross-shore distribution of longshore sediment transport as measured by Bodge and Dean (Bodge 1986, Bodge and Dean 1987a, 1987b) at Duck, North Carolina, and in the laboratory (cont)Application of longshore sediment transport calculations.EXAMPLE PROBLEM III-2-7EXAMPLE PROBLEM III-2-7 (cont)EXAMPLE PROBLEM III-2-7 (cont) - Part_III-Chap_20052EXAMPLE PROBLEM III-2-7 (cont) - Part_III-Chap_20053Variations in longshore sediment transport along the coastThree-dimensionality of shoreline features.Figure lll-2-23. Beach cusps on a sandy beach in Mexico (photograph courtesy of Paul Komar)Table lll-2-3. List of Authors Postulating Theories for Cusp DevelopmentFigure III-2-25. Rhythmic shoreline features associated with the presence of crescentic bars welded to the shorelineThree-dimensionality of shoreline features. (cont)Empirical shoreline models.Figure III-2-27. Spiral bay geometry: (a) definition sketch and (b) coefficients describing parabolic shoreline shape (Silvester and Hsu 1993)Analytical longshore sand transport shoreline change models.Figure lll-2-29. Definition of local breaker angleEXAMPLE PROBLEM III-2-8Analytical longshore sand transport shoreline change models. (cont)Figure lll-2-30. Structure placed perpendicular to shoreFigure III-2-31. Nondimensionalized solution graphs (at different scales) for the condition of no sand transport at the structure locationFigure lll-2-33. Complementary error functionAnalytical longshore sand transport shoreline change models. (cont)Figure III-2-34. Nondimensional solution curve for plan view of sediment accumulation at a coastal structure after natural bypassing initiatedEXAMPLE PROBLEM III-2-9EXAMPLE PROBLEM III-2-10Figure lll-2-35. Rectangular beach fill (t=0)Figure lll-2-37. Proportion of fill p(t) remaining within limits of rectangular plan view fill areaFigure lll-2-38. Triangular beach fill (t=0)EXAMPLE PROBLEM III-2-11Figure III-2-39. Nondimensional solution curves for triangular initial plan view fill areaFigure lll-2-42. Semi-infinite beach fill (t=0)Figure lll-2-43. Nondimensional solution curve for semi-infinite plan view fill areaFigure lll-2-44. Beach fill placed with groins (t=0)Figure lll-2-46. Width of maintained beach (x < 0) as a function of timeEXAMPLE PROBLEM III-2-12EXAMPLE PROBLEM III-2-12 (cont)Numerical Longshore Sand Transport Beach Change ModelsOne-line (two-dimensional) models.Shoreline Change Model GENESIS.Capabilities and limitations.Example application - Bolsa Chica, California.Figure lll-2-47. Bolsa Chica, California, study area (Gravens 1990a)Figure lll-2-48. Wave transformation hindcast to RCPWAVE grid (Gravens 1990a)Figure lll-2-49. Total littoral drift rose, Anaheim to Santa Ana River (Gravens 1990a)Figure lll-2-50. Model calibration results, Bolsa Chica (Gravens 1990a)Figure lll-2-51. Model verification results, Bolsa Chica (Gravens 1990a)Example application - Bolsa Chica, California. (cont)Figure lll-2-52. Sand management alternative with feeder beach (Gravens 1990a)Figure III-2-53. Predicted shoreline change from 1983 shoreline position with sand management alternative and feeder beach (Gravens 1990a)References - Part_III-Chap_20097References (cont) - Part_III-Chap_20098References (cont) - Part_III-Chap_20099References (cont) - Part_III-Chap_20100References (cont) - Part_III-Chap_20101References (cont) - Part_III-Chap_20102References (cont) - Part_III-Chap_20103References (cont) - Part_III-Chap_20104References (cont) - Part_III-Chap_20105References (cont) - Part_III-Chap_20106References (cont) - Part_III-Chap_20107References (cont) - Part_III-Chap_20108References (cont) - Part_III-Chap_20109References (cont) - Part_III-Chap_20110References (cont) - Part_III-Chap_20111References (cont) - Part_III-Chap_20112References (cont) - Part_III-Chap_20113References (cont) - Part_III-Chap_20114References (cont)\Definition of Symbols - Part_III-Chap_20116Definition of Symbols ( cont)Definition of Symbols ( cont)Acknowledgments - Part_III-Chap_20119Part_III-Chap_2