Coch, N.K., 2016. Sediment dynamics in the Upper and Lower Bays of New York Harbor.A long-term geologic and oceanographic study has provided the first holistic picture of sediment dynamics in the estuaries of SW New York state. Oceanographic data indicates that the east (Brooklyn) part of the Upper Bay is flood dominant, while the western (Staten Island) side is ebb-dominant. Bedform analysis indicates a net northerly (flood) orientation on the eastern side of the Lower Bay. The west side, in contrast, has fine sediment similar to that supplied by the Hudson River to the Upper Bay. The numerous sand borrow pits on the nearshore shelf also reflect a difference in net flow. The eastern pits are filled with shelf sands while the western ones are filled with mixtures of fine Hudson derived sediments and shelf sands. These patterns suggest flood dominant transport of shelf sands from the Lower Bay into the Upper Bay and ebb dominant supply of Hudson-derived fine material into the Lower Bay on the western side. The shelf and Hudson River Estuary are not the only suppliers of sediment to New York Harbor. The East River and Harlem Rivers have supplied significant amounts of coarse sediment to the northern part of the Upper Bay. This continued until massive stream changes in the 19th Century cut off sediment supply. The East and Harlem River sediments were deposited in a delta extending south and west of the Battery in Manhattan. Part of the relict East River material is now being reworked and moved northward by flood dominant nontidal flow along the eastern shore of the Hudson.