Historical and Recent Shoreline Changes, Impacts of Moriches Inlet, and Relevance to Island Breaching at Fire Island National Seashore, NY.

摘要

A geomorphologic study of the natural and anthropogenic responses to an unusually high frequency of large magnitude storms in the early 1990s finds that natural processes return the Fire Island system to a more normal state at different timescales: shorelines within weeks to months; dunes within years; and inlet-affected areas take decades. There are significant shoreline trends persisting over decades but also localized areas of erosion, which migrate westward over months to a few years. Certain areas are identified as more predictable in response direction whereas others are dominated by variation, possibly due to offshore controls on incident wave energy and sediment supply. The latter dominate shoreline activity in the west of Fire Island, which is occupied by 17 communities of weekend to year-around residences with high monetary value being some 60 km away from the center of New York City. The context of a densely developed landscape that is highly dynamic and at risk to several threats, also means that certain policy issues go beyond the science of shoreline change. Known areas of erosion can be actively engineered to resist such threats but more innovative adjustments to ocean and bayside erosion would provide cost-effective, storm-hazard protection, based upon natural reconstruction processes, conjoined with many environmental benefits.