Sommerfield, 2003: Upper Delaware Estuary

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Frequently-anticipated questions:

What does this data set describe?

    Title: Sommerfield, 2003: Upper Delaware Estuary
    "In cooperation with the Delaware River Basin Commission (DRBC), Delaware Department of Natural Resources and Environmental Control (DNREC), and Environmental Protection Agency Region III (EPA), a sedimentological and geophysical study of the upper Delaware Estuary was conducted during 2001-2002 by researchers from the College of Marine Studies and the Department of Geology, University of Delaware. The overarching objective of this project was to assist DRBC in identifying sediment depositional zones within the upper estuary, and to quantify rates of accumulation, ultimately to help constrain the loading history of toxic compounds from point and non-point sources (DRBC, 1998). The specific goals were to: (1) generate a comprehensive map of sedimentary environments with respect to bottom morphology and sediment type, and (2) develop sediment chronologies for select muddy depositional sites revealed through sonar observations or otherwise specified by DRBC. To accomplish these goals, extensive sidescan and chirp sonar surveys and sediment sampling of the estuarine floor and shallow subbottom were conducted aboard the RV Cape Henlopen (University of Delaware) and the RV Lear (EPA) between April and December of 2001. Sidescan and chirp sonars were used to obtain acoustic remote sensing data on bottom sedimentary environments and identify regions of fine-grained sediment deposition, i.e., possible pollutant depocenters. Downcore distributions of the radioisotopes Cs-137 and Pb-210 were measured at these sites to estimate recent sedimentation rates. Initial radioisotope measurements at several sites within the subtidal estuary revealed that the most recent sedimentary record is incomplete and therefore unable to yield unambiguous sediment chronologies. As a substitute, selected tidal marsh and river-floodplain sites in Delaware and New Jersey assumed (and later confirmed) to be amenable to radioisotope geochronology were visited between March and July 2002 for push-core sampling. Interim results of this study were presented at the 2002 Geological Society of America meeting (Sommerfield and Madsen, 2002), as well as at the 2002 TMDL Symposium in Philadelphia. A timeline of the field and laboratory components of this study is provided in Table 1."

  1. How should this data set be cited?

    Sommerfield, Christopher K. , 2003, Sommerfield, 2003: Upper Delaware Estuary.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -75.582070
    East_Bounding_Coordinate: -74.935270
    North_Bounding_Coordinate: 40.034220
    South_Bounding_Coordinate: 39.222480

  3. What does it look like?

    sommerfield2.jpg (JPEG)
    Image map showing extent and distribution of data layer coverage

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 2001
    Ending_Date: 2002
    Currentness_Reference: ground condition

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: tabular digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • Entity point (489)

    2. What coordinate system is used to represent geographic features?

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.400000.
      The flattening of the ellipsoid used is 1/294.978698.

  7. How does the data set describe geographic features?


    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Feature geometry. (Source: ESRI)

    Coordinates defining the features.




    The following fields were entered into usSEABED: TXR data: % Gravel:% Sand:% Silt:% Clay:% Mud LTH data: FolkClasses

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    Please review cross reference information for original data set credit to Sommerfield, 2003.

  3. To whom should users address questions about the data?

    Dr. Christopher K. Sommerfield
    University of Delaware, Graduate College of Marine Studies
    Assistant Professor of Oceanography
    700 Pilottown Road
    Lewes, Delaware 19958

    (302) 645-4255 (voice)
    (302) 645-4007 (FAX)

Why was the data set created?

"The overarching objective of this project was to assist DRBC in identifying sediment depositional zones within the upper estuary, and to quantify rates of accumulation, ultimately to help constrain the loading history of toxic compounds from point and non-point sources (DRBC, 1998)."

How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    (process 1 of 1)
    Digital data were checked, formatted to dbSEABED input format, then processed using dbSEABED software to produce a range of output formats. The processing contained quality checking that may have declined to pass faulty or suspect data to outputs.

    Person who carried out this activity:

    Chris Jenkins
    Institute of Arctic & Alpine Research (INSTAAR) University of Colorado at Boulder
    1560 30th Street
    Boulder, CO 80309-0450

    (303) 492-6387 (voice)
    (303) 492-6388 (FAX)

    Data sources used in this process:
    • CH01-28 grainsize.xls: Sheet=CH01-28
    • CH01-28 grainsize.xls Sheet= CH01-28
    • sommerfieldJan04.xls Sheet=sample locns
    • sommerfieldJan04.xls Sheet=porosity

  3. What similar or related data should the user be aware of?

    Sommerfield, Christopher K. , and Madsen, John A. , 2003, Sedimentological and Geophysical Survey of the Upper Delaware Estuary.

    Online Links:

    Final Report to Delaware River Basin Commission 25 State Police Drive PO Box 7360 West Trenton, New Jersey 08628-0360
    Madsen, John A. , and Sommerfield, Christopher K. , 2003, Application of side -scan sonar, sub-bottom profiling, and echo-sounding techniques to study sediment deposition and erosion in estuaries: Results from the lower Delaware River and upper Delaware Bay: U.S. Hydro 2003 Conference Session 2.3, The Hydrographic Society of America (THSOA).

    Online Links:

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

  5. How consistent are the relationships among the observations, including topology?

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None.
Use_Constraints: None.

  1. Who distributes the data set?[Distributor contact information not provided.]

  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    Although this data set has been used by the U.S. Geological Survey (USGS), no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Trade, firm, or product names and other references to non-USGS products and services are provided for information only and do not constitute endorsement or warranty, express or implied, by the USGS, USDOI, or U.S. Government, as to their suitability, content, usefulness, functioning, completeness, or accuracy.

  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 25-May-2005
Last Reviewed: 03-May-2005

Metadata author:
Jamey Reid
U.S. Geological Survey
IT Specialist (Data Management)
384 Woods Hole Rd.
Woods Hole, MA 02543-1598

(508) 548-8700 x2204 (voice)
(508) 457-2310 (FAX)

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

Metadata extensions used:

Generated by mp version 2.7.33 on Wed May 25 13:29:49 2005