South Atlantic Water Science Center - North Carolina Office

Rating Unsaturated Zone and Watershed Characteristics of Public Water Supplies - Updates

Metadata - Unsaturated Zone Rating

• Identification Information
• Data Quality Information
• Spatial Data Organization Information
• Spatial Reference Information
• Entity and Attribute Information
• Distribution Information
• Metadata Reference Information

Metadata elements shown with blue text are defined in the Federal Geographic Data Committee's (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM). Elements shown with green text are defined in the ESRI Profile of the CSDGM. Elements shown with a green asterisk (*) will be automatically updated by ArcCatalog. ArcCatalog adds hints indicating which FGDC elements are mandatory; these are shown with gray text.

Identification Information:

Citation:

Citation information:

Originators: Silvia Terziotti

*Title:

inher_gw

*File or table name: inher_gw

Publication date: 2009

Edition: Version 1.0, June 30, 2009

*Geospatial data presentation form: raster digital data

Publication information:

Publication place: Raleigh, NC

Publisher: U.S. Geological Survey

*Online linkage: \\Igsavbewfs001\Work\SWAP_updates\FinalLayers\GW\inher_gw

Description:

Abstract:

This data set represents the ratings applied to the unsaturated
zone for North Carolina. It is one of 6 data
sets updated for the North Carolina Public Water Supply, Source
Water Assessment Program. These data are used to rate the susceptibility of
public water supplies in North Carolina to contamination.

The original dataset was produced in 2000. This version is updated to reflect new data sources.

The selected factors contributing to the unsaturated zone rating
for ground-water supplies include vertical series hydraulic conductance,
land-surface slope, land cover, and land use. For ground-water systems,
the higher the inherent vulnerability of the unsaturated zone, the
higher the rating applied on a scale of 10 to 100.

Purpose:

The purpose of this data set is to rate the susceptibility to
contamination of the unsaturated zone for public ground-water supplies.

Supplemental information:

The 1996 Amendments to the Safe Drinking Water Act require that each state prepare a source-water assessment for all public water supplies. States are required to (1) delineate source areas supplying wells and surface-water intakes, (2) inventory potential contaminant sources within the delineated source areas, and (3) determine the susceptibility of wells or intakes to the inventoried potential contaminant sources.

In North Carolina, the lead agency charged with this task is the Public Water Supply Section (PWSS) of the Division of Environmental Health, Department of Environment and Natural Resources (DENR). North Carolina's Source Water Assessment Program (SWAP) provides assessments of each public drinking water intake in North Carolina. These assessments provide a relative susceptibility rating calculated using state-wide data.

The U.S. Geological Survey (USGS) cooperated with the PWSS to provide components of the inherent vulnerability rating that was used with the contaminant rating to determine the overall susceptibility rating of source water supplies. To assist the PWSS with rating ground water inherent vulnerability, the USGS compiled the unsaturated zone rating based on the following characteristics: vertical hydraulic conductance, depth to water, land surface slope, land use and land cover. The watershed characteristic rating includes average annual precipitation, land surface slope, land use, land cover and groundwater contribution.

The SWAP program has planned for updates to the initial ratings as conditions change and new data sources become available. The initial data used to calculate the unsaturated zone ratings and watershed characteristics ratings were compiled from sources from the late 1990's. Critical data layers have been updated since the ratings were calculated. These improved data layers need to be used in the ongoing update of the susceptibility ratings.

Overlay and index methods for rating susceptibility to contamination
of the unsaturated zone for ground-water suppplies, and watershed
characteristics for surface-water supplies were derived for use
by the State of North Carolina in assessing more than 11,000 public
water-supply wells and approximately 245 public surface-water intakes.
Factors that influence the inherent vulnerability of ground water and
surface water were selected and assigned ratings on a scale of 1 to 10.
These factors were then assigned weight to reflect their relative influence
on inherent vulnerability and the reliability of the data.  The
values for each factor were obtained from geographic information
system (GIS) data layers that were transformed into ARC/INFO
raster data sets known as grids. These raster data sets have
30-meter by 30-meter cells, and each cell is assigned a weighted-
factor value.

Limitations --

The overlay and index methods of unsaturated zone and watershed
characteristics ratings are broad-stroke methods that assess
vulnerability on the basis of expert opinion. The methods aslo have
limitations in the age and scale of the hydrologic and geographic
data. But the most significant limitation of the methods used
is that no statistical confirmation of the results have been
performed.

UNSATURATED ZONE RATING --

The relative unsaturated zone rating is based on a combination of
factors that contribute to the likelihood that contaminants from
surface and shallow sources will reach the water table by following
the path of aquifer recharge. The selected factors, which are
represented by GIS spatial-data layers, include vertical series
conductance of the unsaturated zone, land-surface slope, land cover,
and land use.

The values of each of these four factors are categorized,
and the categories are assigned a rating on a scale of
1 to 10. A rating of 1 reflects a low contribution to inherent
vulnerability and 10 reflects a high contribution.  For example,
the rating for land-surface slope is low (1) in areas of high slope
(greater than 50 percent) and high (10) in areas of low slope
(less than 2 percent) because increased infiltration potential in
flatter terrain leads to an increased likelihood of ground-water
contamination.

With the exception of land use, these factors describe influences
on the physical transport of water, with or without contaminants.
The land-use factor is included as a measure of the potential for
generating nonpoint-source contamination at land surface.  For
the purpose of calculating the unsaturated zone rating, each of these
four factors is weighted on the basis of importance of the factor
in determining vulnerability.  Vertical series conductance and land
use are weighted more heavily than are land-surface slope and land
cover.

For each cell, the product of the factor weights and ratings are
summed to determine the total rating for the cell, resulting in
a relative numerical unsaturated zone rating that ranges from
10 to 100 for each cell.

>Factors contributing to the unsaturated zone rating.
>
>Description                                               Weight
>
>Vertical series conductance of the unsaturated zone           3
>The harmonic mean of a series of layers of unsaturated
>material provides a single value for the capacity of the
>entire sequence of the unsaturated zone to transmit water
>(with or without contaminants) from the land surface to
>the water table.
>
>Land-surface slope                                            2
>The inclination or slope of the land surface indicates
>the likelihood that precipitation will infiltrate or
>run off.
>
>Land cover                                                    2
>The type of material covering the land surface
>influences the likelihood that precipitation will
>infiltrate into the ground or run off the land surface.
>
>Land use                                                      3
>The type of land use influences the likelihood of
>potential nonpoint-source contamination.
>

SELECTED REFERENCES:

Eimers, J. L., Weaver, J. C., Terziotti, S., and Midgette, R. W.,
2000, Methods of rating unsaturated zone and watershed
characteristics of public water supplies in North Carolina: U. S.
Geological Survey Water-Resources Investigations Report 99-4283,
31 p.

Heath, R. C., 1994, Ground water recharge in North Carolina:
Groundwater Section, North Carolina Department of Environmental
Management, informal report, 52 p.

North Carolina Department of Environment and Natural Resources,
1999, North Carolina source water assessment program plan: Raleigh,
North Carolina Department of Environment and Natural Resources,
Division of Environmental Health, Public Water Supply Section,
[variously paged].

DISCLAIMER:

Any use of trade, product, or firm names is for descriptive purposes
only and does not imply endorsement by the
U.S. Government.

Although this Federal Geographic Data Committee-compliant metadata
file is intended to document the data set in nonproprietary form,
as well as in ARC/INFO format, this metadata file may include some
ARC/INFO-specific terminology.

*Language of dataset: en

Time period of content:

Time period information:

Single date/time:

Calendar date: 2009

Currentness reference:

Ground Condition

Status:

Progress: In work

Maintenance and update frequency: As Needed

Spatial domain:

Bounding coordinates:

*West bounding coordinate: -84.901283

*East bounding coordinate: -74.884006

*North bounding coordinate: 36.982818

*South bounding coordinate: 33.256483

Local bounding coordinates:

*Left bounding coordinate: 83406.419070

*Right bounding coordinate: 976386.419070

*Top bounding coordinate: 358675.256043

*Bottom bounding coordinate: -39784.743957

Keywords:

Theme:

Theme keywords: Inherenent Vulnerability, soils, land use, land cover, ground water, slope, elevation

Theme keyword thesaurus: none

Place:

Place keywords: North Carolina

Place keyword thesaurus: none

Access constraints: none

Use constraints:

Not to be used for site specific analysis

Point of contact:

Contact information:

Contact person primary:

Contact person: Silvia Terziotti

Contact organization: U.S. Geological Survey

Contact position: Computer Specialist

Contact address:

Address type: mailing address

Address:

3916 Sunset Ridge Road

City: Raleigh

State or province: NC

Postal code: 27607

Country: USA

Contact voice telephone: (919) 571-4000

Contact facsimile telephone: (919) 571-4041

Contact electronic mail address: (seterzio@usgs.gov)

Data set credit:

The authors are grateful to colleagues in the Public Water Supply
Section of the Division of Environmental Health, North Carolina
Department of Environment and Natural Resources (DENR) for their
assistance in this collaborative project: thanks to Robert Midgette,
Protection and Enforcement Branch Head; Amy Axon,hydrogeologist - Source Water Protection; and David Hammermann, Geographic Information Systems Specialist.

The authors also thank the USGS report review team for their review of
the update procedures: Jeanne Robbins, Surface-water Specialist; Melinda Chapman, Ground-water Specialist; Mary Giorgino, Water-quality Specialist; and Douglas Harned, ALBE-National Water Quality Assessment Project Chief

*Native dataset format: Raster Dataset

*Native data set environment:

Microsoft Windows 2000 Version 5.2 (Build 3790) Service Pack 2; ESRI ArcCatalog 9.2.6.1500

Cross reference:

Citation information:

Originators: Silvia Terziotti and Jo Leslie Eimers

Title:

Watershed Characteristics Rating for North Carolina

Publication date: 2001

Geospatial data presentation form: map

Series information:

Series name: USGS Open-File Report

Issue identification: USGS OFR 01-490

Publication information:

Publication place: Raleigh, NC

Publisher: USGS

Online linkage: http://nc.water.usgs.gov/reports/ofr01490/index.html

Cross reference:

Citation information:

Originators: Silvia Terziotti and Jo Leslie Eimers

Title:

Unsaturated Zone Characteristics Rating for North Carolina

Publication date: 2001

Geospatial data presentation form: map

Series information:

Series name: USGS Open-File Report

Issue identification: USGS OFR 01-489

Publication information:

Publication place: Raleigh, NC

Publisher: USGS

Online linkage: http://nc.water.usgs.gov/reports/ofr01489/index.html

Cross reference:

Citation information:

Originators: Silvia Terziotti and Jo Leslie Eimers

Title:

Land-Use Classes to Characterize Watersheds and the Unsaturated Zone in North Carolina

Publication date: 2001

Geospatial data presentation form: map

Series information:

Series name: USGS Open-File Report

Issue identification: USGS OFR 01-493

Publication information:

Publication place: Raleigh, NC

Publisher: USGS

Online linkage: http://nc.water.usgs.gov/reports/ofr01493/index.html

Cross reference:

Citation information:

Originators: Silvia Terziotti and Jo Leslie Eimers

Title:

Land-Cover Classes to Characterize the Unsaturated Zone in North Carolina

Publication date: 2001

Geospatial data presentation form: map

Series information:

Series name: USGS Open-File Report

Issue identification: USGS OFR 01-491

Publication information:

Publication place: Raleigh, NC

Publisher: USGS

Online linkage: http://nc.water.usgs.gov/reports/ofr01491/index.html

Cross reference:

Citation information:

Originators: Silvia Terziotti and Jo Leslie Eimers

Title:

Percent-Slope Classes to Characterize the Unsaturated Zone in North Carolina

Publication date: 2001

Geospatial data presentation form: map

Series information:

Series name: USGS Open-File Report

Issue identification: USGS OFR 01-495

Publication information:

Publication place: Raleigh, NC

Publisher: USGS

Online linkage: http://nc.water.usgs.gov/reports/ofr01495/index.html

Cross reference:

Citation information:

Originators: Jo Leslie Eimers, Silvia Terziotti and Gloria Ferrell

Title:

Vertical Series Hydraulic Conductance Classes to Characterize the Unsaturated Zone in North Carolina

Publication date: 2001

Geospatial data presentation form: map

Series information:

Series name: USGS Open-File Report

Issue identification: USGS OFR 01-486

Publication information:

Publication place: Raleigh, NC

Publisher: USGS

Online linkage: http://nc.water.usgs.gov/reports/ofr01486/index.html

Cross reference:

Citation information:

Originators: Jo Leslie Eimers, Silvia Terziotti and Mary Giorgino

Title:

Estimated Depth to Water, North Carolina

Publication date: 2001

Geospatial data presentation form: map

Series information:

Series name: USGS Open-File Report

Issue identification: USGS OFR 01-487

Publication information:

Publication place: Raleigh, NC

Publisher: USGS

Online linkage: http://nc.water.usgs.gov/reports/ofr01487/index.html

Cross reference:

Citation information:

Originators: Silvia Terziotti and Jo Leslie Eimers

Title:

Land-Cover Classes to Characterize Watersheds in North Carolina

Publication date: 2001

Geospatial data presentation form: map

Series information:

Series name: USGS Open-File Report

Issue identification: USGS OFR 01-492

Publication information:

Publication place: Raleigh, NC

Publisher: USGS

Online linkage: http://nc.water.usgs.gov/reports/ofr01492/index.html

Cross reference:

Citation information:

Originators: Silvia Terziotti and Jo Leslie Eimers

Title:

Average Annual Precipitation Classes to Characterize Watersheds in North Carolina

Publication date: 2001

Geospatial data presentation form: map

Series information:

Series name: USGS Open-File Report

Issue identification: USGS OFR 01-494

Publication information:

Publication place: Raleigh, NC

Publisher: USGS

Online linkage: http://nc.water.usgs.gov/reports/ofr01494/index.html

Cross reference:

Citation information:

Originators: Silvia Terziotti and Jo Leslie Eimers

Title:

Percent-Slope Classes to Characterize Watersheds in North Carolina

Publication date: 2001

Geospatial data presentation form: map

Series information:

Series name: USGS Open-File Report

Issue identification: USGS OFR 01-496

Publication information:

Publication place: Raleigh, NC

Publisher: USGS

Online linkage: http://nc.water.usgs.gov/reports/ofr01496/index.html

Cross reference:

Citation information:

Originators: Silvia Terziotti and Jo Leslie Eimers

Title:

Ground-Water Contribution Classes to Characterize Watersheds in North Carolina

Publication date: 2001

Geospatial data presentation form: map

Series information:

Series name: USGS Open-File Report

Issue identification: USGS OFR 01-488

Publication information:

Publication place: Raleigh, NC

Publisher: USGS

Online linkage: http://nc.water.usgs.gov/reports/ofr01488/index.html

Data Quality Information:

Attribute accuracy:

Attribute accuracy report:

visually verified against original source

Logical consistency report:

Not applicable for raster data.

Completeness report:

Completed for the State of North Carolina.

Positional accuracy:

Horizontal positional accuracy:

Horizontal positional accuracy report:

visually verified

Lineage:

Source information:

Source citation:

Citation information:

Originators: Eimers, J. L., Weaver, J. C., Terziotti, S., Midgette, R. W.

Title:

Methods of rating unsaturated zone and watershed characteristics of public water supplies in North Carolina

Publication date: 2000

Series information:

Series name: U. S. Geological Survey Water-Resources Investigations

Issue identification: WRIR 99-4283

Type of source media: paper

Source citation abbreviation:

Eimers and others (2000)

Source contribution:

methods for applying ratings

Source time period of content:

Time period information:

Single date/time:

Calendar date: 2000

Source currentness reference:

publication date

Process step:

Process description:

Create a grid based on the weighted values of the contributing
factors.
inher_gw = ( ..\landcover\landcovergw * 2 ) +
( ..\landuse\landusegw * 3 ) + ( ..\soils\condgw * 3 ) +
( ..\slope\slopegw * 2 )

Process date: 2009

Process step:

Process description:

First draft of metadata created by seterzio using
FGDCMETA.AML ver. 1.33 07/15/99 on ARC/INFO data set
h:\gw_layers\inher_gw

Process date: 2009

Process step:

Process description:

Metadata imported.

Source used citation abbreviation:

W:\SWAP_updates\Documents\Metadata\inher_gw.xml

Spatial Data Organization Information:

*Direct spatial reference method: Raster

Raster object information:

*Image format:

*Number of bands: 1

*Row count: 13282

*Column count: 29766

*Vertical count: 1

*Cell size X direction: 30.000000

*Cell size Y direction: 30.000000

*Bits per pixel: 8

*Pyramid layers: FALSE

*Image colormap: FALSE

*Compression type: Default

*Raster object type: Grid Cell

*Raster display type: matrix values

*Raster origin: Upper Left

Spatial Reference Information:

Horizontal coordinate system definition:

Coordinate system name:

*Projected coordinate system name: NAD_1983_StatePlane_North_Carolina_FIPS_3200

*Geographic coordinate system name: GCS_North_American_1983

Planar:

Grid coordinate system:

*Grid coordinate system name: State Plane Coordinate System 1983

State Plane Coordinate System:

*SPCS zone identifier: 3200

Lambert conformal conic:

*Standard parallel: 34.333333

*Standard parallel: 36.166667

*Longitude of central meridian: -79.000000

*Latitude of projection origin: 33.750000

*False easting: 609601.220000

*False northing: 0.000000

Planar coordinate information:

*Planar coordinate encoding method: row and column

Coordinate representation:

*Abscissa resolution: 30.000000

*Ordinate resolution: 30.000000

*Planar distance units: meters

Geodetic model:

*Horizontal datum name: North American Datum of 1983

*Ellipsoid name: Geodetic Reference System 80

*Semi-major axis: 6378137.000000

*Denominator of flattening ratio: 298.257222

Entity and Attribute Information:

Detailed description:

*Name: inher_gw.vat

Entity type:

*Entity type label: inher_gw.vat

*Entity type type: Table

*Entity type count: 70

Attribute:

Attribute label: Rowid

Attribute definition:

Internal feature number.

Attribute definition source:

ESRI

Attribute domain values:

Unrepresentable domain:

Sequential unique whole numbers that are automatically generated.

Attribute:

Attribute label: VALUE

Attribute:

Attribute label: COUNT

Overview description:

Entity and attribute overview:

>
>Value attribute table, INHER_GW.VAT:
>
>COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME
>    1  VALUE                  4    10     B      -
>    5  COUNT                  4    10     B      -
>
VALUE is rating between 10 and 100.
COUNT is the number of 30 meter by 30 meter cells that have the
value in positive integers.
In the final data set, the values range from 12 to 84.

>Summary statistics table, INHER_GW.STA:
>
>COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC  ALTERNATE NAME
>    1  MIN                    8    15     F      3
>    9  MAX                    8    15     F      3
>   17  MEAN                   8    15     F      3
>   25  STDV                   8    15     F      3

MIN is the minimum value.
MAX is the maximum value.
MEAN is the average value.
STDV is the standard deviation.

>   MIN             MAX            MEAN            STDV
>12.000          84.000          52.873          10.973

Entity and attribute detail citation:

none

Distribution Information:

Distributor:

Contact information:

Contact organization primary:

Contact organization: U.S. Geological Survey

Contact position: Information Officer

Contact address:

Address type: mailing and physical address

Address:

3916 Sunset Ridge Rd.

City: Raleigh

State or province: NC

Postal code: 27607

Country: USA

Contact voice telephone: (919) 571-4000

Contact electronic mail address: gs-w-ncrlg_www@usgs.gov

Contact instructions:

Contact via email

Resource description: Downloadable Data

Distribution liability:

Although these data have been used by the U.S. Geological Survey,
U.S. Department of the Interior, no warranty expressed or implied
is made by the U.S. Geological Survey as to the accuracy of the
data.

The act of distribution shall not constitute any such warranty,
and no responsibility is assumed by the U.S. Geological Survey in
the use of this data, software, or related materials.

Standard order process:

Digital form:

Digital transfer information:

*Transfer size: 120.582

*Dataset size: 120.582

Metadata Reference Information:

*Metadata date: 20090702

Metadata review date: 2009

*Language of metadata: en

Metadata contact:

Contact information:

Contact organization primary:

Contact person: North Carolina Water Science Center Director

Contact organization: U.S. Geological Survey

Contact position: Director

Contact address:

Address type: mailing and physical address

Address:

3916 Sunset Ridge Road

City: Raleigh

State or province: NC

Postal code: 27607

Country: USA

Contact voice telephone: (919) 571-4000

Contact facsimile telephone: (919) 571-4041

Contact electronic mail address: dc_nc@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 access constraints: none

Metadata use constraints:

none

Metadata extensions:

Online linkage: http://www.esri.com/metadata/esriprof80.html

Profile name: ESRI Metadata Profile

Metadata extensions:

*Online linkage: http://www.esri.com/metadata/esriprof80.html

*Profile name: ESRI Metadata Profile

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