The U.S. Geological Survey, in cooperation with the National Oceanic and Atmospheric Administration and the Connecticut Department of Environmental Protection, has produced detailed geologic maps of the sea floor in Long Island Sound, a major East Coast estuary surrounded by the most densely populated region of the United States. These studies have built upon cooperative research with the State of Connecticut that was initiated in 1982. The current phase of this research program is directed toward studies of sea-floor sediment distribution, processes that control sediment distribution, nearshore environmental concerns, and the relation of benthic community structures to the sea-floor geology. Anthropogenic wastes, toxic chemicals, and changes in land-use patterns resulting from residential, commercial, and recreational development have stressed the environment of the Sound, causing degradation and potential loss of benthic habitats (Koppelman and others, 1976; Long Island Sound Study, 1994). Detailed maps of the sea floor are needed to help evaluate the extent of adverse impacts and to help manage resources wisely in the future. Therefore, in a continuing effort to better understand Long Island Sound, we have constructed and interpreted multibeam bathymetric data within specific areas of special interest. The geologic interpretation of the acoustic data from survey H11252 in Geographic presented herein covers a roughly 64 km square area of the sea floor in the area just west of Six Mile Reef, eastern Long Island Sound. The original multibeam bathymetric data were collected during 2004 as part of charting applications aboard the NOAA Survey Vessel Thomas Jefferson. A Simrad EM1002 multibeam system mounted on the hull of this vessel was used to acquire data along survey lines from the deeper water (>20 m) parts of the study area. Two 29-foot launches with hull-mounted Reson systems were deployed from the ship and were used to acquire data along survey lines from the shallower areas. Detailed bathymetric data and their interpretations serve many purposes, including: (1) defining the geological variability of the sea floor, which is one of the primary controls of benthic habitat diversity; (2) improving our understanding of the processes that control the distribution and transport of bottom sediments and the distribution of benthic habitats and associated infaunal community structures; and (3) providing a detailed framework for future research, monitoring, and management activities. The bathymetric data models also serve as base maps for subsequent sedimentological, geochemical, and biological observations, because precise information on environmental setting is important for selection of sampling sites and for accurate interpretation of point measurements.

The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal sea floor. Bathymetry, originally collected by NOAA for charting purposes, provides a fundamental framework for research and management activities off southern New England, shows the composition and terrain of the seabed, and provides information on sediment transport and benthic habitat. During July-August 2008 NOAA completed hydrographic survey H11922 west of Gay Head, Massachusetts, in Rhode Island Sound and during July and September 2010 bottom photographs and surficial sediment data were acquired as part of ground-truth reconnaissance surveys of this area. Interpretations were derived from the multibeam echo-sounder data and the ground-truth data used to verify them. For more information on the ground-truth surveys see http://quashnet.er.usgs.gov/data/2010/10033/ and http://quashnet.er.usgs.gov/data/2010/10005/

The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal sea floor. Bathymetric data, originally collected by NOAA for charting purposes, provide a fundamental framework for research and management activities along this part of Block Island Sound, show the composition and terrain of the seabed, and provide information on sediment transport and benthic habitat. During June 2013, bottom photographs and surficial sediment data were acquired as part of a ground-truth reconnaissance survey of this area. Interpretations were derived from the multibeam-echosounder, sedimentary, and photographic data collected in Block Island Sound. For more information on the ground-truth survey see https://cmgds.marine.usgs.gov/fan_info.php?fan=2013-005-FA.

The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal sea floor. Bathymetry and sidescan-sonar imagery, originally collected by NOAA for charting purposes, provides a fundamental framework for research and management activities in Long Island Sound, shows the composition and terrain of the seabed, and provides information on sediment transport and benthic habitat. During October 2008 NOAA completed hydrographic survey H11997 offshore in eastern Long Island Sound, and during May 2010 bottom photographs and surficial sediment data were acquired as part of a ground-truth reconnaissance survey of this area. Two interpretive data layers were derived from the multibeam echo-sounder and the ground-truth data used to verify them. For more information on the ground-truth survey see http://quashnet.er.usgs.gov/data/2010/10015/

The U.S. Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial geology in estuaries along the coast of the northeastern United States. The purpose of our present study is to define the sea floor morphology and sedimentary environments in an area of Rhode Island Sound using sidescan-sonar and bathymetric data collected onboard the NOAA Ship RUDE, as well as historic seismic records. The mosaic, bathymetry, and their interpretations serve many purposes, including: (1) defining the geological variability of the sea floor, which is one of the primary controls of benthic habitat diversity; (2) improving our understanding of the processes that control the distribution and transport of bottom sediments and the distribution of benthic habitats and associated infaunal community structures; and (3) providing a detailed framework for future research, monitoring, and management activities. The sidescan-sonar mosaics and bathymetry images also serve as base maps for subsequent sedimentological, geochemical, and biological observations, because precise information on environmental setting is important for selection of sampling sites and for accurate interpretations of point measurements.

The U.S. Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial geology in estuaries along the coast of the northeastern United States. The purpose of our present study is to define the sea floor morphology and sedimentary environments in an area of Rhode Island Sound using sidescan sonar imagery, multibeam bathymetry, and seismic records. The mosaic, bathymetry, and their interpretations serve many purposes, including: (1) defining the geological variability of the sea floor, which is one of the primary controls of benthic habitat diversity; (2) improving our understanding of the processes that control the distribution and transport of bottom sediments and the distribution of benthic habitats and associated infaunal community structures; and (3) providing a detailed framework for future research, monitoring, and management activities. The sidescan sonar mosaics and bathymetry images also serve as base maps for subsequent sedimentological, geochemical, and biological observations, because precise information on environmental setting is important for selection of sampling sites and for accurate interpretations of point measurements.

The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA) and the Connecticut Department of Energy and Environmental Protection (CT DEEP), is producing detailed geologic maps of the coastal sea floor. Bathymetry and sidescan-sonar imagery, originally collected by NOAA for charting purposes, provide a fundamental framework for research and management activities in Long Island Sound, shows the composition and terrain of the seabed, and provides information on sediment transport and benthic habitat. During April-May 2009 NOAA completed hydrographic survey H12013 offshore of the entrance to the Connecticut River, and during November 2009 and April 2010 bottom photographs and surficial sediment data were acquired as part of two ground-truth reconnaissance surveys of this area. Two interpretive data layers were derived from the multibeam echo-sounder and the ground-truth data used to verify them. For more information on the ground-truth surveys see: http://woodshole.er.usgs.gov/operations/ia/public_ds_info.php?fa=2009-059-FA and http://woodshole.er.usgs.gov/operations/ia/public_ds_info.php?fa=2010-010-FA

The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal sea floor. Bathymetric and sidescan-sonar data, originally collected by NOAA for charting purposes, provide a framework for research and management activities along western Block Island Sound, show the composition and terrain of the seabed, and provide information on sediment transport and benthic habitat. During June 2013, bottom photographs and surficial sediment data were acquired as part of a ground-truth reconnaissance survey of this area. Interpretations were derived from the multibeam-echosounder, sidescan-sonar, sedimentary, and photographic data collected in Block Island Sound. For more information on the ground-truth survey see https://cmgds.marine.usgs.gov/fan_info.php?fan=2013-005-FA.

The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal sea floor. Bathymetry and sidescan-sonar imagery, originally collected by NOAA for charting purposes, provides a fundamental framework for research and management activities in Long Island Sound, shows the composition and terrain of the seabed, and provides information on sediment transport and benthic habitat. During October 2008 NOAA completed hydrographic survey H11997 offshore in eastern Long Island Sound, and during May 2010 bottom photographs and surficial sediment data were acquired as part of a ground-truth reconnaissance survey of this area. Two interpretive data layers were derived from the multibeam echo-sounder and the ground-truth data used to verify them. For more information on the ground-truth survey see http://quashnet.er.usgs.gov/data/2010/10015/

The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal sea floor. Bathymetric and sidescan-sonar data, originally collected by NOAA for charting purposes, provide a fundamental framework for research and management activities along this part of Block Island Sound, show the composition and terrain of the seabed, and provide information on sediment transport and benthic habitat. During June 2012, bottom photographs and surficial sediment data were acquired as part of a ground-truth reconnaissance survey of this area. Interpretations were derived from the multibeam-echosounder, sidescan-sonar, sedimentary, and photographic data collected in Block Island Sound. For more information on the ground-truth survey see .