Waves Against Cape Cod: An Uneasy Truce by Victor and Yvonne E. Goldsmith

The Cape Naturalist: Vol 1 No 1

June, 1972

The outer beach of Cape Cod from Provincetown to Monomoy Point may be considered to be 30 miles out to sea, and as such, is subject to the relentless attack of the waves. However, the outer beach has shown that it is capable of adjusting to the continuous onslaught of the waves through changes in the shoreline configuration. Two of these coastal processes will be discussed in detail.

The Growing Shield. A glance at a map shows that the outer beach of Cape Cod resembles a curved shield which appears to protect the Cape from the storm waves generated out in the Atlantic. Most of the waves approach Cape Cod from the east-northeast. The cliff and beach of the outer Cape in the Truro vicinity, in the center of the shield, are oriented perpendicular to the dominant wave approach direction, and so receive the brunt of the wave attack. North of Highland Light and south of Marconi Station the east-northeast waves approach the outer Cape shoreline at an oblique angle, and some of the wave energy is transformed into longshore currents which flow parallel to the shore and in the general direction of the wave advance. These currents transport much of the sediment eroded from the Truro cliffs to Race Point and Long Point to the northwest, and to Nauset Spit and Monomoy Island to the south. Indeed all four of these features were formed as a direct result of the processes of wave induced longshore currents discussed above.

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