HR: 1340h
AN: OS23A-1528    [Abstracts]
TI: Combining Data From Bathymetry, Sub-Bottom Profiles, and Sediment Cores to Improve Sediment Budget and Accumulation Rates in the Hudson River
AU: * Nitsche, F O
EM: fnitsche@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Kenna, T
EM: tkenna@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Bell, R E
EM: robinb@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Ryan, W B
EM: billr@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Carbotte, S M
EM: carbotte@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Chillrud, S
EM: chilli@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Flood, R D
EM: Roger.Flood@stonybrook.edu
AF: Marine Sciences Research Center, Stony Brook University, Stony Brook, NY 11794 United States
AB: Estuarine environments are sensitive to changes in sea level or run-off from the watershed as well as to human modification such as dredging and shoreline alterations. Such changes affect the balance between import and export of sediments from and to the system as well as the patterns of deposition and erosion in the system itself. Detailed knowledge of this pattern of erosion and deposition and how this pattern has changed over time is important to understand the behavior of estuaries in response to past changes and will allow predicting the impact of future changes. In addition, many management issues require accurate knowledge of depositional sites and sediment budget. Comparison of soundings from 1930s with multibeam bathymetry data from the Hudson River Benthic Mapping Project collected in 1999-2003 shows that there was significant change in several parts of the Hudson River Estuary between this two surveys and that there is a large variability of depositional and erosional areas along the 240 km long Hudson River Estuary. Geophysical measurements such as sidescan sonar and sub-bottom profiling provide details on the spatial extent of deposits, but their vertical resolution is low compared to sediment cores, and sub-bottom data do not yield direct timing information for the calculation of accumulation rates. In contrast, analyses of sediment cores provide high vertical resolution and accumulation rates, but they yield no detailed information on the lateral extent of deposits. To obtain a detailed inventory of some key depositional sites, we compared the depositional layer identified in the sub-bottom data with Cesium 137 profiles obtained from sediment cores and the change in bathymetry. Although each single method has it uncertainties, combining bathymetry data, sub-bottom profiles, and sediment cores enabled us to obtain consistent and more accurate estimates of sediment volumes and accumulation rates in the Hudson River Estuary.
DE: 3000 MARINE GEOLOGY AND GEOPHYSICS
DE: 3022 Marine sediments: processes and transport
DE: 4235 Estuarine processes (0442)
SC: Ocean Sciences [OS]
MN: Fall Meeting 2005