Raw Continuous Resistivity Profiles Collected in the Neuse River, May 3, 2005

Metadata:

• Identification_Information
• Data_Quality_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: John F. Bratton

Originator: VeeAnn A. Cross

Publication_Date: 2005

Title:

Raw Continuous Resistivity Profiles Collected in the Neuse River, May 3, 2005

Online_Linkage:

<http://pubs.usgs.gov/of/2005/1306/data/2005/raw_resis/may3_raw.zip>

Larger_Work_Citation:

Citation_Information:

Originator: VeeAnn A. Cross

Originator: John F. Bratton

Originator: Emile Bergeron

Originator: Jeff K. Meunier

Originator: John Crusius

Originator: Dirk Koopmans

Publication_Date: 2005

Title:

Continuous Resistivity Profiling Data from the Upper Neuse River Estuary, North Carolina, 2004-2005

Series_Information:

Series_Name: Open-File Report

Issue_Identification: 2005-1306

Publication_Information:

Publication_Place: Woods Hole Science Center, Woods Hole, MA

Publisher: U.S. Geological Survey, Coastal and Marine Geology Program

Online_Linkage: <http://pubs.usgs.gov/of/2005/1306>

Description:

Abstract:

The Neuse River Estuary in North Carolina is a broad, V-shaped water body located on the southwestern end of Pamlico Sound. This estuary suffers from severe eutrophication for which several water quality models have recently been developed to aid in the management of nutrient loading to the estuary. In an effort to help constrain model estimates of the fraction of nutrients delivered by direct ground-water discharge, continuous resistivity profile (CRP) measurements were made during the spring of 2004 and 2005. CRP is used to measure electrical resistivity of sediments, a property that is sensitive to difference in salinity of submarine ground water. The 2004 and 2005 surveys used floating resistivity streamers of 100 m and 50 m respectively. The depth penetration of the streamers is approximately 20% of the streamer length which translates to approximately 20-25 m with the 100 m streamer and 12-14 m with the 50 m streamer. These data were processed using AGI's EarthImager 2D software. CRP data enables the mapping of the extent and depth of the fresher ground water within the estuary.

Purpose:

To provide the raw resistivity data as collected by the AGI SuperSting system.

Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 20050503

Currentness_Reference: ground condition

Status:

Progress: Complete

Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -77.026133

East_Bounding_Coordinate: -76.852833

North_Bounding_Coordinate: 35.089283

South_Bounding_Coordinate: 34.942333

Keywords:

Theme:

Theme_Keyword_Thesaurus: General

Theme_Keyword: CMGP

Theme_Keyword: coastal

Theme_Keyword: Coastal and Marine Geology Program

Theme_Keyword: Continuous Resistivity Profiling

Theme_Keyword: CRP

Theme_Keyword: ground-water

Theme_Keyword: marine resistivity

Theme_Keyword: submarine ground-water

Theme_Keyword: U.S. Geological Survey

Theme_Keyword: USGS

Theme_Keyword: Woods Hole Science Center

Theme_Keyword: Open-File Report

Theme_Keyword: OF 2005-1306

Place:

Place_Keyword_Thesaurus: General

Place_Keyword: Neuse River

Place_Keyword: North America

Place_Keyword: North Carolina

Place_Keyword: Pamlico Sound

Place_Keyword: United States

Access_Constraints: none.

Use_Constraints:

The U.S. Geological Survey must be referenced as the originator of the dataset in any future products or research derived from these data.

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: John F. Bratton

Contact_Organization: U.S. Geological Survey

Contact_Address:

Address_Type: mailing and physical address

Address: 384 Woods Hole Rd.

City: Woods Hole

State_or_Province: MA

Postal_Code: 02543-1598

Contact_Voice_Telephone: (508) 548-8700 x2254

Contact_Facsimile_Telephone: (508) 457-2310

Native_Data_Set_Environment:

Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.0.0.535

Data_Quality_Information:

Lineage:

Source_Information:

Source_Contribution:

These data were acquired with an AGI SuperSting Marine system that is described at the website: www.agiusa.com/marinesystem.shtml. The particular system used for this acquisition was an 11 electrode array with electrodes spaced 5 meters apart. The potential electrodes are made of graphite, with the remaining electrodes stainless steel. A dipole-dipole configuration was used for the data collection in which two fixed current electrodes are assigned with the measurement of voltage potentials between electrode pairs in the remaining electrodes. Each line of data acquisition records several files. The two files necessary for processing are the *.stg and *.gps file. The STG file contains the resistivity data, while the GPS file contains the navigation information.

Process_Step:

Process_Description:

The data were transferred from the logging computer via AGISSAdmin software. The data file available for this day is L1F1.*.

Process_Step:

Process_Description:

When the data were acquired, a scaling factor of 5 was used. However, because the initialization file already defined the electrodes as being 5 meters apart, this had the affect of indicating the electrodes were 25 meters apart. Therefore, Marine Log Manager was used to rescale the STG file, by using a scale factor of 0.2, to return the electrodes to the appropriate spacing.

Source_Used_Citation_Abbreviation: L1F1.stg

Source_Produced_Citation_Abbreviation: L1F1_rescaled.stg

Process_Step:

Process_Description:

The fathometer was placed in a poor location on this day of surveying, essentially placing incorrect depth values in the GPS file. Another system (Radon) was acquiring valid fathometer data, so this information was to be incorporated into the resistivity GPS file. Unfortunately, the radon system lost navigation for approximately 1 hour (including bathymetry data), and that system only records a reading once a minute. To incorporate what radon data was of use, I first deleted any 0 navigation fix lines from the radon file. The radon file was then parsed with a python script (radonparse_nav2005withbathy.py). The resulting text file was then loaded as an event theme into ArcView and converted to s shapefile.

Source_Produced_Citation_Abbreviation: day1radon.shp

Process_Step:

Process_Description:

At the same time, I took the reformatted GPS resistivity file and loaded it as an event theme to ArcView and converted it to a shapefile.

Source_Produced_Citation_Abbreviation: templ1f1.shp

Process_Step:

Process_Description:

I then did a spatial join between the radon shapefile and the resistivity shapefile. This new table I exported to a text file. I renamed some column headings, brought it into ArcView as an event theme, and converted it to a shapefile.

Source_Produced_Citation_Abbreviation: l1f1_joinradon.shp

Process_Step:

Process_Description:

I then added the filed "bestbathy" to l1f1_joinradon.shp. My first thought was to do a spatial join with the remaining resistivity lines to derive bathymetric values. However, this would not work due to the wind tide issue. The resistivity processing needs water depths at the time of acquisition, and with increased weather issues, the depth values in certain areas were very different between days. Instead, I used an avenue script to extract grid values from the estuary bathymetry grid to populate a "gridbathy" attribute.

Process_Step:

Process_Description:

The shapefile was queried and any radon value (from the same day) within 25 meters of the resistivity point was used to populate the "bestbathy" field.

Process_Step:

Process_Description:

The selection was then inverted and the high resolution bathymetry grid extracted values were used to populate the "bestbathy" field. This value was justified by a comparison of the high-resolution bathymetry to the radon bathymetry from the day of interest. In almost all cases, the radon bathymetry and the grid bathymetry were within 0.5 meters of one another.

Process_Step:

Process_Description:

All fields not needed were turned off in the table properties, and the resulting table was exported to a comma delimited text file.

Source_Produced_Citation_Abbreviation: l1f1_bestbathy.txt

Process_Step:

Process_Description:

This comma delimited text file was run through an awk script (awknewgps_bathy) to generate a gps file in the format used by Marine Log Manager.

Source_Used_Citation_Abbreviation: l1f1_bestbathy.txt

Source_Produced_Citation_Abbreviation: l1f1_fixbathy.gps

Distribution_Information:

Resource_Description: Downloadable Data

Distribution_Liability:

These data were prepared by an agency of the United States Government. Neither the United States government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. Although all data published in this report have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials.

Metadata_Reference_Information:

Metadata_Date: 20051101

Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: VeeAnn A. Cross

Contact_Organization: U.S. Geological Survey

Contact_Position: Marine Geologist

Contact_Address:

Address_Type: mailing and physical address

Address: 384 Woods Hole Rd.

City: Woods Hole

State_or_Province: MA

Postal_Code: 02543-1598

Contact_Voice_Telephone: (508) 548-8700 x2251

Contact_Facsimile_Telephone: (508) 457-2310

Contact_Electronic_Mail_Address: vatnipp@usgs.gov

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Time_Convention: local time

Metadata_Extensions:

Online_Linkage: <http://www.esri.com/metadata/esriprof80.html>

Profile_Name: ESRI Metadata Profile