ESTUARY FACIES MODELING OF HISTORIC WETLANDS AND STREAM-NETWORKS OF BROOKLYN AND QUEENS, NY

Long Island, NY represents a coastal plain system encompassing two of the most populated boroughs in New York City (Brooklyn and Queens). Brooklyn and Queens contain various wetland complexes and stream networks that developed during the interglacial Pleistocene and Holocene Epochs. Both boroughs experience frequent flash flooding and coastal flooding events that can re-active ancient stream networks, inundating historic wetlands that underlie the city streets. In the geologic past, flooding was a natural process that contributed to the formation of Long Island but is now a major concern for the citizens of New York.

Infrastructure development led to the modification of the natural landscapes and flood-drainage networks of the island, contributing to urban flooding during extreme weather events. Using reports of geologic cores across Brooklyn and Queens, a subsurface estuary lithofacies map was created to identify the underlying historical floodways and wetlands of the latest Pleistocene and Holocene Epochs. Sedimentary core reports were utilized to project the underlying stratigraphy of Long Island to identify flood and wetland associated deposits. A map representing the drainage pattern and geomorphology of Long Island was constructed using Geographic Information Systems (GIS). Historical maps, geologic reports and historical documentation of New York City infrastructure development, were used to illustrate drainage patterns over time compared to current flood trends of NYC. They showed a high correlation of ancient floodplains and wetlands to areas that experience high occurrences of flooding events today. This research is advantageous for infrastructure planning and flood mitigation strategies for coastal cities by providing new methods in identifying high risk flood areas in an urban environment. The created maps will (1) identify flood hot spots in an urban environment and (2) detect natural drainage systems that can be re-established as optimal flow routes for surface water drainage.