MARSH COASTLINE CHANGES OBSERVED THROUGH GEOGRAPHIC INFORMATION SYSTEM: LIDO NATURE BEACH PRESERVE, LONG ISLAND, NY

Coastal areas are affected by natural and anthropomorphic change. The Lido Beach Passive Nature Area is located on the South Shore of Long Island within the Town of Hempstead, New York. The Lido preserve is about 38 acres of about 7,000 acres of Spartina marsh in the Town of Hempstead and 20,000 acres of combined tidal wetland types within the Township. Seventy-five percent of the property is marsh.

The marshes in this area have decreased in size in the last fifty years. Within a 50 nautical mile radius of Lido Beach, both modern and historical records indicate that 59 hurricanes, tropical and extra-tropical storms have affected the area. 1985's category 2 Hurricane Gloria, 1976's category 1 Hurricane Belle and unnamed hurricanes, which occurred in 1893 and 1938 are the strongest of these storms. Storm surges can cause dune retreat, splay deposits and marsh erosion among other effects. This is a semi-permanent to permanent change to the ecosystem. As part of a larger study on hurricane strikes in the region, this study seeks to identify changes to the coastline from 1926 to the present. Special attention will be paid to the changes in coastline before and after hurricane events.

Through Hempstead township records, aerial photography (1926, 1956, 1966, 1968, 1973 and 1983), digital photography (1994, 2000, and 2004) area maps and commercially available satellite imagery (Tiger Data 2000, ESRI, NYS GIS Clearinghouse); a Geographical Information System (ESRI ArcGIS suite) a visual description will be produced to established change along this coastline. Digitized aerial photos and maps will be overlaid with parcel and street centerline shapefiles to show the progression of coastline change. Additionally, a larger project is looking at the stratigraphy of the marsh, so core locations were captured using a high-resolution GPS unit (Leica 1200) and subsequently placed on the GIS. The vibra-cores of the marsh examine whether the storm records can be observed downcore in the sedimentary units.

The storms effects, as well as the increase in development of the area, show abrupt changes in the Lido Beach area. These can be further quantified as percent marsh area lost through time. Thus the aim of this project is to document the amount of marsh loss that has been observed.