Kerhin, R.T., Halka, J.P., Wells, D.V., Hennessee, E.L., Blakeslee, P.J., Zoltan, N., and Cuthbertson, R.H., 1998, Chesapeake Bay Earth Science Study (CBESS): Physical Properties of Surficial Sediments, Cheseapeake Bay, Maryland (Tabular Data): Maryland Geological Survey, Baltimore, MD, USA.Online Links:
This is a Vector data set. It contains the following vector data types (SDTS terminology):
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.
Sequential unique whole numbers that are automatically generated.
Coordinates defining the features.
Funding for the Chesapeake Earth Science Study was provided by the U.S. Environment Protection Agency (EPA) under Contract No. EPA R805965.
Jeffrey Halka
Maryland Geological Survey
Chief, Coastal and Estuarine
2300 St. Paul Street
Baltimore, MD 21218
USA
410-554-5543 (voice)
410-554-5502 (FAX)
jhalka@mgs.dnr.md.gov
- Hours_of_Service: 9am - 5pm
One component of the Chesapeake Bay Earth Science Study (CBESS) was a baseline inventory of Chesapeake Bay bottom sediments, more particularly of those properties or features (e.g. sediment type, water content, sulfur content, carbon content, rate of sediment accumulation or erosion) that affect the distribution of toxic substances. The project, funded by the Environmental Protection Agency (Contract No. EPA R805965), was a cooperative effort between the states of Maryland and Virginia. The Maryland Geological Survey and the Virginia Institute of Marine Science (VIMS) were responsible for sampling and analyzing sediments deposited in the waters of their respective states. Information contained in this data set is for Maryland only.
Person who carried out this activity:
Jeffrey Halka
Maryland Geological Survey
Chief, Coastal and Estuarine Geology Program
2300 St. Paul Street
Baltimore, MD 21218
USA
(410) 554-5543 (voice)
(410) 554-5502 (FAX)
jhalka@mgs.dnr.md.gov
- Hours_of_Service: 9am - 5pm
Person who carried out this activity:
Jane ReidData sources used in this process:
U.S. Geological Survey
Geologist
400 Natural Bridges Drive
Santa Cruz, CA 95060
USA
(831) 427-4727 (voice)
(831) 427-4748 (FAX)
jareid@usgs.gov
Person who carried out this activity:
Jane Reid
U.S. Geological Survey
Geologist
400 Natural Bridges Drive
Santa Cruz, CA 95060
USA
(831) 427-4727 (voice)
(831) 427-4748 (FAX)
jareid@usgs.gov
Person who carried out this activity:
Jane Reid
U.S. Geological Survey
Geologist
400 Natural Bridges Drive
Santa Cruz, CA 95060
USA
(831) 427-4727 (voice)
(831) 427-4748 (FAX)
jareid@usgs.gov
Byrne, R.J., Hobbs, C.H., and Carron, M.J., Baseline sediment studies to determine distribution, physical properties, sedimentation budgets and rates in the Virginia portion of the Cheseapeake Bay.
This section of the metadata summarizes information found in an appendix to the report by Kerhin and others (1988) cited in Section 1.2.3 Supplemental Information. It will be easier to understand this section if you first read Section 2.5 Lineage. Quality assurance for grain-size analysis involved three major components: (1) calibration of the individual analytical instruments, (2) inter-calibration of specially designed instruments with similar devices at the Virginia Institute of Marine Sciences (VIMS), and (3) duplicate analyses at MGS and VIMS of sediments collected in both Maryland and Virginia waters. Instrument Calibration Calibration of the rapid sediment analyzer (RSA) was accomplished through the use of glass beads of known size, sphericity and density. Calibration of the Coulter Counter was accomplished through procedures recommended in the manufacturer's operating manual. At the time of the CBESS study, most previous sedimentological studies had used pipetting techniques, rather than a Coulter Counter, to determine the size distribution of fine-grained sediments. Therefore, for three sediment samples, MGS compared results obtained by the two methods. For all three samples, the grain-size distribution resulting from Coulter Counter analysis was somewhat finer than that determined by pipette analysis. The difference in the mean grain size calculated by each technique ranged from a low of 0.07f for one sample to a high of 0.29f for another. For each sample, the envelope enclosing the Coulter Counter data was smaller than that for the pipette data, indicating the superior precision of the Coulter Counter technique. Two possible explanations were offered to account for the difference in results obtained by the two techniques: (1) particle density or shape effects, and (2) an instrument "noise" effect. The second effect probably contributed more to the observed differences; Coulter Counter operators noticed that machine noise tended to accumulate in the output channels representing the finer end of the size distribution. In any case, the differences between the two techniques were quite small. The greater precision of the Coulter Counter, coupled with its ease of operation, recommended its use. Inter-Laboratory Calibration Both MGS and VIMS processed 20 sediment samples, representative of a broad range of sediment types, to compare results from the two laboratories. Eight samples were collected from the Bay in Virginia, and 12 from Maryland. Each of the paired samples matched on Shepard's class. For 14 of the samples, both institutions were able to determine mean grain size. The analytical results were compared statistically, using a t-test for dependent samples. At the 5% level of significance, there were no differences between the results obtained by MGS and VIMS.
Sample collection, surficial samples were collected according to two different protocols, "nearshore" or "mid-bay". Accuracy of nearshore sample location was estimated to be ñ 30 m. Teledyne-Hastings, the manufacturer of the Raydist radionavigational system used to locate mid-bay samples, reported the positional accuracy of the system as ñ 0.5 m. To ensure accuracy, the crew checked calibrations at least twice during each sampling day. Based on these checks, operational accuracy was about ñ 1.5 m. However, due to such factors as vessel orientation, wind, and tidal currents, mid-bay sampling accuracy was estimated to be ñ 10 m.
Water depths recorded at each sampling site were not adjusted for tide level.
Omissions The main trunk of the Maryland portion of the Chesapeake Bay was sampled, as well as Eastern Bay, the Choptank River, and Tangier Sound. Within the study area, no samples were collected in the vicinity of Aberdeen Proving Ground or Bloodsworth Island because of the risk of retrieving unexploded ordnance. Selection criteria Total carbon, organic carbon, and total sulfur determinations were made for about 25% of the samples collected. Initially, every mid-bay and certain nearshore samples were analyzed, providing coverage on a 1-km grid. Sampling density was reduced when it became apparent that carbon and sulfur analyses could not keep pace with other phases of the project. Results from the early analyses showed that in 85% of the sandy samples, carbon and sulfur were below detection. Based on those findings, sandy samples - usually nearshore samples characterized by low water content - were excluded from analysis. Later in the project, every fourth mid-bay sample was analyzed, provided that its water content exceeded 25% by weight. If water content fell below that limit, the sample was generally replaced by a neighboring one.
Data were checked for permissible values. For most of the parameters measured, "-999" indicates a missing value.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None.
- Use_Constraints:
- Consider the age of the data (1976-1984), the sampling density (1-km grid) and the spatial and temporal variability of estuarine sediments in evaluating the fitness for use of this data set. Graphic displays and printed tabular listings derived from this data set may be used in publications and presentations, provided that credit is given to the originators of the data set. The Maryland Geological Survey (MGS) makes no warranty, either express or implied, as to the use or appropriateness of the data, and there are no warranties of merchantability or fitness for a particular purpose or use. MGS may not be subject to liability for human error, defect, or failure of machines, or any material used in connection with the machines, including tapes, disks, punchcard and energy. MGS may not be liable for any lost profits, consequential damages, or claims against the user by third parties.
Jeffrey Halka
Maryland Geological Survey
Chief, Coastal and Estuarine Geology Program
2300 St. Paul Street
Baltimore, MD 21218
USA
(410) 554-5543 (voice)
(410) 554-5502 (FAX)
jhalka@mgs.dnr.md.gov
- Hours_of_Service: 9am - 5pm
CBESS: Physical Properties of Surficial Sediments, Cheseapeake Bay, Maryland (Tabular Data)
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
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No fees apply if the data set is downloaded from the Internet. A CD-ROM containing the data set and the metadata files costs $25.
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)
jreid@usgs.gov