"Threes," an Unusual Surfing Spot at Shinnecock Inlet, New York
ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB
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Interactions among waves, tide, wind, jetties, and inlet morphology create and enhance surfable waves within Shinnecock Inlet, New York. Threes, a popular local surf break, can be experienced only during certain combinations of incident wave height, period, direction, and wind direction and tidal elevation. Threes is activated if waves from the south-southeast to south-southwest propagate into the inlet, reflect first off the east jetty, then off the west jetty, and break on a bayside shoal extending from the western barrier island. In maintenance of the jetties at Shinnecock Inlet, the U.S. Army Corps of Engineers tries to accommodate requests of surfers for preserving conditions favorable for Threes. Observations indicate Threes can only be surfed around slack low tide, when the tidal current velocity in the inlet is weak. The resulting waves can reach approximately 1.5 to 2 m in height and plunge along the shoal for 20 to 30 m, giving a surfing duration of 5 to 8 sec. In this paper, the Threes phenomenon is discussed and successfully simulated with the CGWAVE numerical model. An implication is that surfing amenities can be reliably designed with numerical models.
- Physical and Dynamic Oceanography