Isles Derneries, Gulf Side Transects

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Frequently-anticipated questions:

What does this data set describe?
    Title: Isles Derneries, Gulf Side Transects
    Abstract:
    The U.S. Geological Survey (USGS), in cooperation with the Coastal Research Laboratory in the Department of Geology and Geophysics at the University of New Orleans (UNO) and the Center for Coastal Energy and Environmental Resources at Louisiana State University (LSU), is investigating the processes of coastal erosion and wetland loss in Louisiana (Sallenger and others, 1987; Sallenger and Williams 1989; Penland and others, 1992).

    Building on the USGS Louisiana Barrier Island Study (Williams and others, 1992) and the USGS Hurricane Andrew impact assessment (Penland and others, 1998), this data layer depicts the shore-normal transects used to measure shoreline change.

    The Isles Dernieres are located about 120 km southwest of New Orleans. This barrier island shoreline is 32 km long and extends from Caillou Bayou east to Wine Island Pass. The Isles Dernieres represent a barrier island arc developed from the reworking and erosion of an abandoned distributary of the Lafourche delta complex within the Mississippi River delta plain (Penland and others, 1988). Previous work by McBride and others (1992) documented a long-term (1887-1988) gulfside erosion rate of -11.1 m/y and a short-term (1978-1988) gulfside erosion rate of -19.2 m/y. The long-term bayside (1906- 1988) erosion rate was measured at -0.6 m/y and the short-term (1978-1988) bayside erosion rate was measured at -5.2 m/y. The Isles Dernieres decreased in area at a rate of -28.2 ha/y between 1887 and 1988, suggesting the long-term date of disappearance would be 2015. The rate of area loss between 1978 and 1988 was measured at -42.7 ha/y suggesting a short-term disappearance date of 2004. In the 1992 Hurricane Andrew impact assessment by Penland and others (1998), the Isles Dernieres experienced a brief and intense period of increased erosion. The average gulfside erosion rate accelerated to -59.37 m/y and the average bayside erosion rate accelerated to -10.8 m/y during the year of the 1992 Hurricane Andrew impact. The Isles Dernieres rate of area change accelerated to -155.7 ha/y during the 1992 hurricane season. Hurricane Andrew accelerated the long-term area loss rate to -28.5 ha/y and the shortterm area loss rate to -49.54 ha/y. The Hurricane Andrew impact on the Isles Dernieres produced 3-5 years of erosion in a matter of days. After the Hurricane Andrew impact, the projected long-term disappearance date of the Isles Dernieres was reduced from 2015 to 2012 and the short term disappearance date was reduced from 2004 to 2003.

    In this shoreline change update, the authors used the methods and transects used by McBride and others (1992) to insure data compatibility of the new measurements and analysis.

    To evaluate change in the shoreline position, shore-normal transects were constructed at approximately 15-second intervals of longitude or latitude depending on shoreline orientation. Isles Dernieres, Bayou Lafourche and Plaquemines barrier systems (east-west shroelines) were analyzed using 15-second (about 404 m) intervals of longitude, while the Chandeleur Islands (north-south shorelines) were examined by using 15-second (about 462 m) intervals of latitude. Measurements of shoreline movement and change in island width were taken along transects perpendicular to the composite shoreline trend. Average rates of movement and area change were calculated by dividing absolute measurements by elapsed time (year, month, and day - where available.) Shoreline change maps were procuded to determine the spatial and temporal distribution of shoreline movement (magnitude, direction, and rate of change) and document geomorphologic evolution. (McBride and others, 1992).

  1. How should this data set be cited?

    Reid, Jamey M. , 2003, Isles Derneries, Gulf Side Transects: U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Field Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Williams, S.J., Reid, J.M., Cross, V., and Polloni, C., 2003, Coastal Erosion and Wetland Change in Louisiana: Selected USGS Products: Digital Data Series DDS-79, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Field Center Woods Hole, MA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -90.963439
    East_Bounding_Coordinate: -90.581319
    North_Bounding_Coordinate: 29.099566
    South_Bounding_Coordinate: 29.023309

  3. What does it look like?

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

    Calendar_Date: 1996
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: vector 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):

      • String (91)

    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 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

  7. How does the data set describe geographic features?

    id_trans_gulf

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    ENTITY

    LAYER

    LEVEL

    ELEVATION

    COLOR

    TRANSECT_N

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?

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

    University of New Orleans
    c/o Paul Connor, Jr
    Dept. of Geology & Geophysics, Pontchartrain Institute, CRM Bldg. Room 343
    New Orleans, LA 70148
    USA

    (504) 280-1030 (voice)
    (504) 280-4022 (FAX)
    pfconnor@crl.uno.edu

Why was the data set created?
To release data that was originally intended to be published in a paper atlas in a digital format.

To up-date the shoreline change analysis by McBride and others (1992) and Penland and others (1998) for the Isles Dernieres to 1996.

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 2)
    The projection was defined as UTM and converted to Geographic NAD 83.

    Person who carried out this activity:

    U.S. Geological Survey
    c/o Jamey M. Reid
    IT Specialist (Data Management)
    Woods Hole Field Center
    Woods Hole, MA 025453-1598
    USA

    (508) 548-8700 x 2204 (voice)
    (508) 457-2310 (FAX)
    jreid@usgs.gov

    (process 2 of 2)
    Metadata was created for the new shapefile.

    Person who carried out this activity:

    U.S. Geological Survey
    c/o Jamey M. Reid
    IT Specialist (Data Management)
    Woods Hole Field Center
    Woods Hole, MA 025453-1598
    USA

    (508) 457-2204 (voice)
    (508) 457-2310 (FAX)
    jreid@usgs.gov

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 1 of 1)

    U.S. Geological Survey
    c/o S. Jeffress Williams
    Geologist
    Woods Hole Field Center
    Woods Hole, MA 02543-1598
    USA

    (508) 457-2383 (voice)
    (508) 457-2310 (FAX)
    jwilliams@usgs.gov

  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, express 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.

  4. How can I download or order the data?

Who wrote the metadata?
Dates:
Last modified: 25-Jul-2003

Metadata author:
U.S. Geological Survey
c/o Jamey M. Reid
IT Specialist (Data Management)
Woods Hole Field Center
Woods Hole, MA 025453-1598
USA

(508) 548-8700 x 2204 (voice)
(508) 457-2310 (FAX)
jreid@usgs.gov

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

Metadata extensions used:

Generated by mp version 2.7.3 on Wed Aug 06 09:23:20 2003