. Collected reprints / Atlantic Oceanographic and Meteorological Laboratories [and] Pacific Oceanographic Laboratories. Oceanography 274 COASTAL SEDIMENTATION. FIGURE 15. Variant of the littoral transport model with a more deeply embayed coast and an oblique direction of wave approach. Conventions as in Fig. 14. Thus, as a consequence of the submarine refraction o waves about the shoals off headlands, the shoreface tends toward an equilibrium plan view as well as an equilib- rium profile. Headlands tend to be suppressed and bays filled, because their existence leads to longshore
. Collected reprints / Atlantic Oceanographic and Meteorological Laboratories [and] Pacific Oceanographic Laboratories. Oceanography 274 COASTAL SEDIMENTATION. FIGURE 15. Variant of the littoral transport model with a more deeply embayed coast and an oblique direction of wave approach. Conventions as in Fig. 14. Thus, as a consequence of the submarine refraction o waves about the shoals off headlands, the shoreface tends toward an equilibrium plan view as well as an equilib- rium profile. Headlands tend to be suppressed and bays filled, because their existence leads to longshore wave power gradients that transfer sand from headland to bay head. A similar smoothing process operates at deeper levels on the shoreface, where sand transport occurs in response to tide- and wind-driven currents. Such flows accelerate past the projecting headlands which impede them, and expand and decelerate off the bays. The result is a posi- tive discharge gradient on the upcurrent sides of the headlands, and a negative discharge gradient on the downcurrent side. This pattern reverses when the cur- rents themselves reverse, so that the lower shoreface off headlands experiences net erosion, while the lower shore- face off bays experiences aggradation. Thus the equilib- rium plan view of a coast tends to be straight, to the extent that variations in the homogeneity of the sub- strate and the rate of sand supply to the surf zone will permit. A second characteristic of equilibrium coastal con- figuration is the adjustment of the trend of the coast to the angle of wave approach as mediated by the rates and locations that sand is put into and taken out of a littoral drift cell. A perfectly straight and infinitely long coast could ideally maintain any angle to wave ap- proach, if the only source of sand were its own shoreface erosion. In fact, however, such an ideal straight coast is rarely attained. Sea level is rising or has been until very recently, and the straightening process
Size: 1159px × 2155px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionamericana, booksponsorlyrasismemb
