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TRANSPORT STUDIES IN THE LOCK LAKE TIDAL MARSH OF SOUTHERN LONG ISLAND
Citation:
Weaver, J W., M. C. Boufadel, AND B. Naba. TRANSPORT STUDIES IN THE LOCK LAKE TIDAL MARSH OF SOUTHERN LONG ISLAND. Presented at 2002 American Geophysical Union Spring Meeting, Washington, DC, May 28-31, 2002.
Impact/Purpose:
The current focus is to 1.) develop, distribute, and support the FRAMES-3MRA modeling technology, 2) to apply the FRAMES-3MRA modeling technology for the purposes of executing national and site-specific risk assessments, 3) to complete model application case studies to explore model performance issues, such as, model validation, 5) to collaborate with other Federal Agencies in an effort to leverage expertise and resources associated with common modeling interests, and 6) to monitor ongoing developments at the Office of Solid Waste and within the environmental modeling community in an effort to identify new needs for science modules and locate or develop solutions within the FRAMES 3MRA modeling system.
Description:
Ground water discharges directly into the Great South Bay and also via a sideways route into the Lock Lake tidal marsh at East Patchogue, New York. Data collected from the site were used to assess the transport of ground water contaminants into the waters of the Bay and potential ecological impacts on the marsh. Sampling included testing for evidence of salt water intrusion from the marsh, continuous water level recording in the aquifer and in marsh stilling wells, and salinity surveys at various locations in the marsh. The aquifer showed no evidence of salt water intrusion from the marsh, but the wells located up to 100 meters from the marsh were strongly influenced by tidal fluctuation. In these wells the direction of ground water flow varied by about 100o over one tidal cycle. Salinity measured at the single outlet of the marsh showed a consistent pattern of high salinity in outflow for about 3 hours after high tide. This was followed by declining salinity that was attributed to the outflow of Bay water recently mixed with fresh water inflows. A vertically-averaged model of the marsh was developed to simulate tidally-varying flows in the marsh, the average salinity in the marsh water, and transport of contaminants within the marsh. Model results show that the flow system is driven by gravity and bottom friction and that the bottom topography is critical for determining the character of flow.