Shoreline change monitoring at Fire Island National Seashore: 2009-2010 annual report

Psuty, Norbert; Hudacek, William; Love, Aaron; Silveira, Tanya

This annual report documents the collection of shoreline position data and describes the short-term variation that has occurred during the period from Spring 2009 to Spring 2010 on the Fire Island barrier island, including elements of the Fire Island National Seashore, as called for in the Northeast Coastal and Barrier Network’s protocol on shoreline monitoring (Psuty, et al., 2010). The changes in shoreline position are generally descriptive of the seasonal contrasts (lower energetics in the summer period versus higher energetics in the winter period) that support sediment accumulation during summer and erosion during the winter. However, there are many natural variables and cultural events that affect the gains and losses of sediment and the displacements of the beach, such as large circulation cells and episodes of beach nourishment. The 1D shoreline surveys were conducted in March 2009, October 2009, and April 2010. They incorporate changes caused by a major beach nourishment project in many of the communities and a county project to place sediment dredged from Moriches Inlet along a portion of Smith Point County Park, both occurring just prior to and in the midst of the March 2009 survey. As a result of shoreline adjustment following the nourishment, most of the communities had a net negative shoreline displacement (mean of -5.09 m) and the County Park had a net negative shoreline displacement for the year (mean of -9.64 m). The NPS lands and the State Park shared in this net inland displacement, -4.56 m and -16.68 m, respectively. The mean shoreline position change for the annual period, Spring 2009 to Spring 2010, for the entire island was an inland displacement, -7.45 m. This annual report on shoreline position change of the Fire Island ocean shoreline does offer some insight into the areas of coastal dynamics and sediment budget. However, it is report on only one year of observations and does not establish a trend. The protocols for shoreline monitoring created a comparable geodatabase that will lead to efficiencies in data assembly and analysis.

Shoreline change monitoring at Fire Island National Seashore: 2009-2010 annual report

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