Beachcam monitoring of shoreline dynamics

Long-term periodic monitoring on New York’s ocean shoreline showed that, despite waxing and waning in the course of any year, beaches have maintained a stable average width between about 200 and 300 feet. To examine the shorter-term patterns of change in the beach width, camera images were calibrated to allow beach widths to be determined. Beach widths measured at low tide varied between less than 60 feet to more than 175 feet between January 2023 and the end of January 2024. A pattern of modulation showed a quasi-cyclical behavior with periods between 5 and 15 days. This seems consistent with the classic synoptic periods of between two and seven days for the passage of mesoscale weather systems. Large variations seem to coincide with wave activity monitored 30 nautical miles south of Long Island (NOAA station 44025) as represented by a “Dalrymple Parameter”1 (Dp) and taking into account wave height, period and sediment settling speed. Beach widths increased at a rate of about 2.5 feet per week as wave activity decreased over the summer.