Identification_Information: Citation: Citation_Information: Originator: Silvia Terziotti Publication_Date: 2009 Title: inher_gw 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. 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 Keywords: Theme: Theme_Keyword_Thesaurus: none Theme_Keyword: Inherenent Vulnerability Theme_Keyword: soils Theme_Keyword: land use Theme_Keyword: land cover Theme_Keyword: ground water Theme_Keyword: slope Theme_Keyword: elevation Place: Place_Keyword_Thesaurus: none Place_Keyword: North Carolina 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_Data_Set_Environment: Microsoft Windows 2000 Version 5.2 (Build 3790) Service Pack 2; ESRI ArcCatalog 9.2.6.1500 Cross_Reference: Citation_Information: Originator: Silvia Terziotti and Jo Leslie Eimers Publication_Date: 2001 Title: Watershed Characteristics Rating for North Carolina 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: Originator: Silvia Terziotti and Jo Leslie Eimers Publication_Date: 2001 Title: Unsaturated Zone Characteristics Rating for North Carolina 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: Originator: Silvia Terziotti and Jo Leslie Eimers Publication_Date: 2001 Title: Land-Use Classes to Characterize Watersheds and the Unsaturated Zone in North Carolina 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: Originator: Silvia Terziotti and Jo Leslie Eimers Publication_Date: 2001 Title: Land-Cover Classes to Characterize the Unsaturated Zone in North Carolina 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: Originator: Silvia Terziotti and Jo Leslie Eimers Publication_Date: 2001 Title: Percent-Slope Classes to Characterize the Unsaturated Zone in North Carolina 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: Originator: Jo Leslie Eimers, Silvia Terziotti and Gloria Ferrell Publication_Date: 2001 Title: Vertical Series Hydraulic Conductance Classes to Characterize the Unsaturated Zone in North Carolina 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: Originator: Jo Leslie Eimers, Silvia Terziotti and Mary Giorgino Publication_Date: 2001 Title: Estimated Depth to Water, North Carolina 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: Originator: Silvia Terziotti and Jo Leslie Eimers Publication_Date: 2001 Title: Land-Cover Classes to Characterize Watersheds in North Carolina 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: Originator: Silvia Terziotti and Jo Leslie Eimers Publication_Date: 2001 Title: Average Annual Precipitation Classes to Characterize Watersheds in North Carolina 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: Originator: Silvia Terziotti and Jo Leslie Eimers Publication_Date: 2001 Title: Percent-Slope Classes to Characterize Watersheds in North Carolina 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: Originator: Silvia Terziotti and Jo Leslie Eimers Publication_Date: 2001 Title: Ground-Water Contribution Classes to Characterize Watersheds in North Carolina 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: Originator: Eimers, J. L. Originator: Weaver, J. C. Originator: Terziotti, S. Originator: Midgette, R. W. Publication_Date: 2000 Title: Methods of rating unsaturated zone and watershed characteristics of public water supplies in North Carolina Series_Information: Series_Name: U. S. Geological Survey Water-Resources Investigations Issue_Identification: WRIR 99-4283 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2000 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Eimers and others (2000) Source_Contribution: methods for applying ratings 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 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell Row_Count: 13282 Column_Count: 29766 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: 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: Entity_Type: Entity_Type_Label: inher_gw.vat 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: 120.585 Metadata_Reference_Information: Metadata_Date: 20090701 Metadata_Review_Date: 2009 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: North Carolina Water Science Center Director 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