Fair weather and storm sand transport on the Long Island, New York, inner shelf

Abstract

Both spring‐summer and fall‐winter sand transport have been observed on the Long Island, New York, inner shelf at water depths of 20‐22 m using a radio‐isotope sand tracer system. The extent of dispersal of the tagged, fine sand was measured at 3 week intervals in two 70 day experiments. In the late spring and early summer, movement was primarily diffusive in nature, extending 100 m around the line of tracer injection, while late fall‐winter patterns had strong advective features, including an ellipsoidal outline extending approximately 1500 m westward of the injection points after the passage of several storms with strong northeasterly winds. Near‐bottom current observations made with Savonius rotor sensors identify the event responsible for the bulk of the transport over the 135 day observation period as a storm flow of 2 days duration. Tracer and current observations together suggest that westward winter storm flow along the Long Island shelf is the major mechanism of sand transport at these depths on a yearly time scale. A least‐squares fit of several of the observed winter patterns with a plume model yields average sediment mass flux lower bounds of 3.2 × 10−3 gm/cm/sec and 1.7 × 10−1 gm/cm/sec for ‘typical’ and extreme winter storm activity.

Alongshore momentum balance over shoreface-connected ridges, Fire Island, NY,

“…The coastline and inner shelf of Fire Island and Long Island, NY have been heavily researched since the 1970's (Flint 1971, Lavelle et al 1978, Rampino 1979, Swift and Field 1981, Rampino and Sanders 1981, Niedoroda and Swift 1981, Swift and Moslow 1982, McBride and Moslow 1991, Kana 1995, Foster et al 1999, Rosati et al 1999, Schwab et al 2000, Hapke et al 2010, Lentz et al 2013, Schwab et al 2013. Long Island, NY is an island formed from the seaward limit of the Wisconsin glacier depositing a large terminal moraine (Flint 1971).…”

A modeling study of the impact of major storms on seabed shear stress and sediment transport on the Grand Banks of Newfoundland

“…While repeated glaciations have strongly affected topography and sediment distribution, the present‐day hydrodynamics and sediment transport and deposition on the Grand Banks are determined by the combined influence of the Labrador Current, the large waves, and strong wind‐driven currents of intense winter storms, as well as moderate tidal currents [ Barrie and Collins , ; Amos and Judge , ]. The storm‐induced currents on the Grand Banks not only are among the strongest compared with other shelf regions, the direction of the currents also rotate clockwise progressively during the passage of a storm, unlike the more rectilinear pattern typically observed on inner‐shelf locations [ Lavelle et al ., ; Vincent et al ., ; Swift et al ., ; Cacchione and Drake , ; Nittrouer and Wright , ]. Influenced by this assemblage of processes, a suite of complex large‐sized bed forms have developed on the seabed [e.g., Barrie et al ., ; Dalrymple et al ., ].…”

“…Journal of Geophysical Research: Oceans 10.1002/2016JC012215 of a storm, unlike the more rectilinear pattern typically observed on inner-shelf locations [Lavelle et al, 1978;Vincent et al, 1981;Swift et al, 1986b;Cacchione and Drake, 1990;Nittrouer and Wright, 1994]. Influenced by this assemblage of processes, a suite of complex large-sized bed forms have developed on the seabed [e.g., Barrie et al, 1984;Dalrymple et al, 1992].…”

Alongshore Momentum Balance Over Shoreface-Connected Ridges, Fire Island, Ny

“…Fire Island's SFCRs are well-sorted with medium-fine grained sand, and have an average amplitude of approximately 8m and spacing of 3km . SFCRs have been recognized globally, but their form varies between tidal and storm dominated shelves, Long Island being storm-dominated (Dragos et al 1990, Lavelle et al 1978 Island to the west. An offshore sediment source has been hypothesized to close this gap, though the forcing has not been recognized (Rosati et al 1999, Hapke et al 2010).…”

“…The coastline and inner shelf of Fire Island and Long Island, NY have been heavily researched since the 1970's (Flint 1971, Lavelle et al 1978, Rampino 1979, Swift and Field 1981, Rampino and Sanders 1981, Niedoroda and Swift 1981, Swift and Moslow 1982, McBride and Moslow 1991, Kana 1995, Foster et al 1999, Rosati et al 1999, Schwab et al 2000, Hapke et al 2010, Lentz et al 2013, Schwab et al 2013). Long…”