Watershed Boundary Dataset (WBD) Data Dictionary

Data dictionary for the Watershed Boundary Dataset (WBD).

WBDHU2

A Comprehensive Aggregated Collection Of Hydrologic Unit Data Consistent With The National Criteria For Delineation And Resolution. The WBD Defines The Perimeters Of Drainage Areas (Hydrologic Units), Formed By The Terrain And Other Landscape Charactersitcs, At A 1:24,000 Scale In The United States, Except For Alaska At 1:63,360 Scale And 1:25,000 Scale In The Caribbean, And It Consists Of Digital Geographic Data That Include Six Levels Of Detailed Nested Hydrologic Unit Boundaries. WBDHU2 Represents The 2-Digit Hydrologic Unit Boundaries (Previously Referred To As Regions) And Are Part Of The WBD Delivery, But These Boundaries Are Not Editable By The WBD In-State Steward. There Are 22 2-Digit Hydrologic Units (Regions) In The WBD

Name	Definition	Type	Allow Nulls	Length	Comments
AreaAcres	AreaAcres is common to all polygon feature classes and is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, acreage values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the required projection to use for calculation.	Double	True
AreaSqKm	AreaSqKm is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, the square kilometer values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the default projection.	Double	True
GNIS_ID	A permanent, unique number assigned by the Geographic Names Information System (GNIS) to a geographic feature name for the sole purpose of uniquely identifying that name application as a record in any information system database, dataset, file, or document	Text	True	10	GNIS_ID = "null" if no name is associated with the feature. Removed from WBD as of version 2.3 schema.
HUC2	The HUC2 field is a unique 2-digit hydrologic unit code.	Text	True	2	This value is used in WBD and NHDPlus HR datasets. For NHDPlus HR, the hydrologic unit is used as a reference during NHDPlus HR data production.
LoadDate	LoadDate represents the date when the data were loaded into the official USGS WBD ArcSDE database. The field is the effective date for all feature edits, and it is automatically generated.	Date	False	22
MetaSourceID	A unique identifier that links the element to the metadata tables. This ID is generated and assigned automatically by the database and remains with the object permanently.	Text	True	40
Name	Name refers to the GNIS name for the geographic area in which the hydrologic unit is located.	Text	False	120
ReferenceGNIS_IDs	Comma delimited list of up to three GNIS_ID's identifying the hydrologic, geologic, or geographic features for which the Hydrologic Unit is named.	Text	True	50	New attribute for WBD 2.3 schema.
Shape_Area	Area of feature in map units squared.	Double	True
Shape_Length	Length of the feature, which may differ from the field measured length due to differences in calculation. Units are map units.	Double	True		All features should have a positive integer value.
SourceDataDesc	SourceDataDesc is a space provided for a brief description of the type of base data used to update or change the current WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	True	100
SourceFeatureID	A long, unique code that identifies the parent of the feature if the feature is the result of a split or merge, and it is automatically generated and assigned.	Text	True	40
SourceOriginator	SourceOriginator is the description of the agency that created the base data used to improve the WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	False	130
States	The States or outlying area attribute identifies the State(s) or outlying areas that the hydrologic unit falls within or touches. The U.S. Census Bureau 1:100,000-scale State layer will be used to establish State boundaries in the derivation process.	Text	True	50	For WBD, indicates the states that contribute drainage to a hydrologic unit area.
TNMID	TNMID (short for The National Map Identification) is a unique 40-character field that identifies each element in the database exclusively.	Text	True	40

WBDHU4

A Comprehensive Aggregated Collection Of Hydrologic Unit Data Consistent With The National Criteria For Delineation And Resolution. The WBD Defines The Perimeters Of Drainage Areas (Hydrologic Units), Formed By The Terrain And Other Landscape Charactersitcs, At A 1:24,000 Scale In The United States, Except For Alaska At 1:63,360 Scale And 1:25,000 Scale In The Caribbean, And It Consists Of Digital Geographic Data That Include Six Levels Of Detailed Nested Hydrologic Unit Boundaries. WBDHU4 Represents The 4-Digit Hydrologic Unit Boundaries (Previously Referred To As Subregions) That Are Part Of The WBD Delivery, But The Boundaries Are Not Editable By The WBD In-State Steward. There Are 222 4-Digit Hydrologic Units (Subregions) In The WBD.

Name	Definition	Type	Allow Nulls	Length	Comments
AreaAcres	AreaAcres is common to all polygon feature classes and is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, acreage values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the required projection to use for calculation.	Double	True
AreaSqKm	AreaSqKm is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, the square kilometer values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the default projection.	Double	True
GNIS_ID	GNIS_ID is a preassigned numeric field that uses a unique number to relate the name of the hydrologic unit to the GNIS names database. This field is automatically generated in the database.	Long Integer	False
HUC4	The HUC4 field is a unique 4-digit hydrologic unit code.	Text	True	4	This value is used in WBD and NHDPlus HR datasets. For NHDPlus HR, the hydrologic unit is used as a reference during NHDPlus HR data production.
LoadDate	LoadDate represents the date when the data were loaded into the official USGS WBD ArcSDE database. The field is the effective date for all feature edits, and it is automatically generated.	Date	False	22
MetaSourceID	A unique identifier that links the element to the metadata tables. This ID is generated and assigned automatically by the database and remains with the object permanently.	Text	True	40
Name	Subregion name refers to the GNIS name for the geographic area in which the hydrologic unit is located.	Text	False	120
ReferenceGNIS_IDs	Comma delimited list of up to three GNIS_ID's identifying the hydrologic, geologic, or geographic features for which the Hydrologic Unit is named.	Text	True	50	New attribute for WBD 2.3 schema.
Shape_Area	Area of feature in map units squared.	Double	True
Shape_Length	Length of the feature, which may differ from the field measured length due to differences in calculation. Units are map units.	Double	True		All features should have a positive integer value.
SourceDataDesc	SourceDataDesc is a space provided for a brief description of the type of base data used to update or change the current WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	True	100
SourceFeatureID	A long, unique code that identifies the parent of the feature if the feature is the result of a split or merge, and it is automatically generated and assigned.	Text	True	40
SourceOriginator	SourceOriginator is the description of the agency that created the base data used to improve the WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	False	130
States	The States or outlying area attribute identifies the State(s) or outlying areas that the hydrologic unit falls within or touches. The U.S. Census Bureau 1:100,000-scale State layer will be used to establish State boundaries in the derivation process.	Text	True	50	For WBD, indicates the states that contribute drainage to a hydrologic unit area.
TNMID	TNMID (short for The National Map Identification) is a unique 40-character field that identifies each element in the database exclusively.	Text	True	40

WBDHU6

A Comprehensive Aggregated Collection Of Hydrologic Unit Data Consistent With The National Criteria For Delineation And Resolution. The WBD Defines The Perimeters Of Drainage Areas (Hydrologic Units), Formed By The Terrain And Other Landscape Charactersitcs, At A 1:24,000 Scale In The United States, Except For Alaska At 1:63,360 Scale And 1:25,000 Scale In The Caribbean, And It Consists Of Digital Geographic Data That Include Six Levels Of Detailed Nested Hydrologic Unit Boundaries. WBDHU6 Represents The 6-Digit Hydrologic Unit Boundaries (Previously Referred To As Basins) And Are Part Of The WBD Delivery, But The Boundaries Are Not Editable By The WBD In-State Steward. Approximately 386 6-Digit Hydrologic Units (Basins) Are In The WBD.

Name	Definition	Type	Allow Nulls	Length	Comments
AreaAcres	AreaAcres is common to all polygon feature classes and is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, acreage values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the required projection to use for calculation.	Double	True
AreaSqKm	AreaSqKm is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, the square kilometer values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the default projection.	Double	True
HUC6	The HUC6 field is a unique 6-digit hydrologic unit code.	Text	True	6	This value is used in WBD and NHDPlus HR datasets. For NHDPlus HR, the hydrologic unit is used as a reference during NHDPlus HR data production.
LoadDate	LoadDate represents the date when the data were loaded into the official USGS WBD ArcSDE database. The field is the effective date for all feature edits, and it is automatically generated.	Date	False	22
MetaSourceID	A unique identifier that links the element to the metadata tables. This ID is generated and assigned automatically by the database and remains with the object permanently.	Text	True	40
Name	Basin name refers to the GNIS name for the geographic area in which the hydrologic unit is located.	Text	False	120
ReferenceGNIS_IDs	Comma delimited list of up to three GNIS_ID's identifying the hydrologic, geologic, or geographic features for which the Hydrologic Unit is named.	Text	True	50	New attribute for WBD 2.3 schema.
Shape_Area	Area of feature in map units squared.	Double	True
Shape_Length	Length of the feature, which may differ from the field measured length due to differences in calculation. Units are map units.	Double	True		All features should have a positive integer value.
SourceDataDesc	SourceDataDesc is a space provided for a brief description of the type of base data used to update or change the current WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	True	100
SourceFeatureID	A long, unique code that identifies the parent of the feature if the feature is the result of a split or merge, and it is automatically generated and assigned.	Text	True	40
SourceOriginator	SourceOriginator is the description of the agency that created the base data used to improve the WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	False	130
States	The States or outlying area attribute identifies the State(s) or outlying areas that the hydrologic unit falls within or touches. The U.S. Census Bureau 1:100,000-scale State layer will be used to establish State boundaries in the derivation process.	Text	True	50	For WBD, indicates the states that contribute drainage to a hydrologic unit area.
TNMID	TNMID (short for The National Map Identification) is a unique 40-character field that identifies each element in the database exclusively.	Text	True	40

WBDHU8

A Comprehensive Aggregated Collection Of Hydrologic Unit Data Consistent With The National Criteria For Delineation And Resolution. The WBD Defines The Perimeters Of Drainage Areas (Hydrologic Units), Formed By The Terrain And Other Landscape Charactersitcs, At A 1:24,000 Scale In The United States, Except For Alaska At 1:63,360 Scale And 1:25,000 Scale In The Caribbean, And It Consists Of Digital Geographic Data That Include Six Levels Of Detailed Nested Hydrologic Unit Boundaries. WBDHU8 Represents The 8-Digit Hydrologic Unit Boundaries (Previously Referred To As Subbasins) And Are Part Of The WBD Delivery, But The Boundaries Are Not Editable By The WBD In-State Steward. Approximately 2,297 8-Digit Hydrologic Units (Subbasins) Are In The WBD.

Name	Definition	Type	Allow Nulls	Length	Comments
AreaAcres	AreaAcres is common to all polygon feature classes and is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, acreage values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the required projection to use for calculation.	Double	True
AreaSqKm	AreaSqKm is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, the square kilometer values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the default projection.	Double	True
GNIS_ID	GNIS_ID is a preassigned numeric field that uses a unique number to relate the name of the hydrologic unit to the GNIS names database. This field is automatically generated in the database.	Long Integer	False
HUC8	The HUC8 field is a unique 8-digit hydrologic unit code.	Text	True	8	This value is used in WBD and NHDPlus HR datasets. For NHDPlus HR, the hydrologic unit is used as a reference during NHDPlus HR data production.
LoadDate	LoadDate represents the date when the data were loaded into the official USGS WBD ArcSDE database. The field is the effective date for all feature edits, and it is automatically generated.	Date	False	22
MetaSourceID	A unique identifier that links the element to the metadata tables. This ID is generated and assigned automatically by the database and remains with the object permanently.	Text	True	40
Name	Subbasin name refers to the GNIS name for the geographic area in which the hydrologic unit is located.	Text	False	120
ReferenceGNIS_IDs	Comma delimited list of up to three GNIS_ID's identifying the hydrologic, geologic, or geographic features for which the Hydrologic Unit is named.	Text	True	50	New attribute for WBD 2.3 schema.
Shape_Area	Area of feature in map units squared.	Double	True
Shape_Length	Length of the feature, which may differ from the field measured length due to differences in calculation. Units are map units.	Double	True		All features should have a positive integer value.
Shape_Length	Length of the feature, which may differ from the field measured length due to differences in calculation. Units are map units.	Double	True		All features should have a positive integer value.
SourceDataDesc	SourceDataDesc is a space provided for a brief description of the type of base data used to update or change the current WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	True	100
SourceFeatureID	A long, unique code that identifies the parent of the feature if the feature is the result of a split or merge, and it is automatically generated and assigned.	Text	True	40
SourceOriginator	SourceOriginator is the description of the agency that created the base data used to improve the WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	False	130
States	The States or outlying area attribute identifies the State(s) or outlying areas that the hydrologic unit falls within or touches. The U.S. Census Bureau 1:100,000-scale State layer will be used to establish State boundaries in the derivation process.	Text	True	50	For WBD, indicates the states that contribute drainage to a hydrologic unit area.
TNMID	TNMID (short for The National Map Identification) is a unique 40-character field that identifies each element in the database exclusively.	Text	True	40

WBDHU10

A Comprehensive Aggregated Collection Of Hydrologic Unit Data Consistent With The National Criteria For Delineation And Resolution. The WBD Defines The Perimeters Of Drainage Areas (Hydrologic Units), Formed By The Terrain And Other Landscape Charactersitcs, At A 1:24,000 Scale In The United States, Except For Alaska At 1:63,360 Scale And 1:25,000 Scale In The Caribbean, And It Consists Of Digital Geographic Data That Include Six Levels Of Detailed Nested Hydrologic Unit Boundaries. WBDHU10 Represents The 10-Digit Hydrologic Unit Boundaries (Previously Referred To As Watersheds). Only The Attribution Is Editable At The 10-Digit Hydrologic Unit By The WBD In-State Steward. Within The United States, Approximately 18,075 10-Digit Hydrologic Units (Watersheds) Are In The WBD.

Name	Definition	Type	Allow Nulls	Length	Domain	Comments
AreaAcres	AreaAcres is common to all polygon feature classes and is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, acreage values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the required projection to use for calculation.	Double	True
AreaSqKm	AreaSqKm is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, the square kilometer values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the default projection.	Double	True
HUC10	The HUC10 field is a unique 10-digit hydrologic unit code.	Text	True	10		This value is used in WBD and NHDPlus HR datasets. For NHDPlus HR, the hydrologic unit is used as a reference during NHDPlus HR data production.
HUMod	The 10-digit hydrologic unit modification attribute is a two-character, uppercase abbreviation(s) for either (1) the type of modification to natural overland flow that alters the natural delineation of a 10-digit hydrologic unit or (2) the special conditions GF-groundwater flow, GL-glacier, IF-ice field, KA-karst, and NC-noncontributing area.	Text	True	30		For HU polygons
HUType	The 10-digit hydrologic unit type attribute is the single-letter abbreviation for Watershed type from the list of official names.	Text	True	1	HUType Domain	Has domain. Updated to 1 character for WBD 2.3 schema.
LoadDate	LoadDate represents the date when the data were loaded into the official USGS WBD ArcSDE database. The field is the effective date for all feature edits, and it is automatically generated.	Date	False	22
MetaSourceID	A unique identifier that links the element to the metadata tables. This ID is generated and assigned automatically by the database and remains with the object permanently.	Text	True	40
Name	Watershed name refers to the GNIS name for the geographic area in which the hydrologic unit is located.	Text	True	120
ReferenceGNIS_IDs	Comma delimited list of up to three GNIS_ID's identifying the hydrologic, geologic, or geographic features for which the Hydrologic Unit is named.	Text	True	50		New attribute for WBD 2.3 schema.
SourceDataDesc	SourceDataDesc is a space provided for a brief description of the type of base data used to update or change the current WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	True	100
SourceFeatureID	A long, unique code that identifies the parent of the feature if the feature is the result of a split or merge, and it is automatically generated and assigned.	Text	True	40
SourceOriginator	SourceOriginator is the description of the agency that created the base data used to improve the WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	False	130
States	The States or outlying area attribute identifies the State(s) or outlying areas that the hydrologic unit falls within or touches. The U.S. Census Bureau 1:100,000-scale State layer will be used to establish State boundaries in the derivation process.	Text	True	50		For WBD, indicates the states that contribute drainage to a hydrologic unit area.
TNMID	TNMID (short for The National Map Identification) is a unique 40-character field that identifies each element in the database exclusively.	Text	True	40

WBDHU12

A Comprehensive Aggregated Collection Of Hydrologic Unit Data Consistent With The National Criteria For Delineation And Resolution. The WBD Defines The Perimeters Of Drainage Areas (Hydrologic Units), Formed By The Terrain And Other Landscape Charactersitcs, At A 1:24,000 Scale In The United States, Except For Alaska At 1:63,360 Scale And 1:25,000 Scale In The Caribbean, And It Consists Of Digital Geographic Data That Include Six Levels Of Detailed Nested Hydrologic Unit Boundaries. WBDHU12 Represents The 12-Digit Hydrologic Unit Boundaries (Previously Referred To As Subwatersheds). Within The United States, Approximately 98,363 12-Digit Hydrologic Units Are In The WBD.

Name	Definition	Type	Allow Nulls	Length	Comments
AreaAcres	AreaAcres is common to all polygon feature classes and is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, acreage values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the required projection to use for calculation.	Double	True
AreaSqKm	AreaSqKm is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, the square kilometer values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the default projection.	Double	True
HUC12	The HUC12 field is a unique 12-digit hydrologic unit code.	Text	True	12	This value is used in WBD and NHDPlus HR datasets. For NHDPlus HR, the hydrologic unit is used as a reference during NHDPlus HR data production.
HUMod	The 10-digit hydrologic unit modification attribute is a two-character, uppercase abbreviation(s) for either (1) the type of modification to natural overland flow that alters the natural delineation of a 10-digit hydrologic unit or (2) the special conditions GF-groundwater flow, GL-glacier, IF-ice field, KA-karst, and NC-noncontributing area.	Text	True	30	For HU polygons
HUType	The 12-digit hydrologic unit type attribute is the single-letter abbreviation for Subwatershed type from the list of official names.	Text	False	1	Has domain
LoadDate	LoadDate represents the date when the data were loaded into the official USGS WBD ArcSDE database. The field is the effective date for all feature edits, and it is automatically generated.	Date	False	22
MetaSourceID	A unique identifier that links the element to the metadata tables. This ID is generated and assigned automatically by the database and remains with the object permanently.	Text	True	40
Name	Subwatershed name refers to the GNIS name for the geographic area in which the hydrologic unit is located.	Text	True	120
NHDPlusID	NHDPlus HR Unique identifier of a NHDFlowline feature. Found in NHDPlus HR Only.	Double	True		This field only exists when NHD feature classes are brought into NHDPlus HR.
NonContributingAreaAcres	Drainage area (acres) that does not contribute flow toward the outlet of a hydrologic unit. New in WBD 2.3 schema.	Double	True
NonContributingAreaSqKm	Drainage area (SqKM) that does not contribute flow toward the outlet of a hydrologic unit.	Double	True
ReferenceGNIS_IDs	Comma delimited list of up to three GNIS_ID's identifying the hydrologic, geologic, or geographic features for which the Hydrologic Unit is named.	Text	True	50	New attribute for WBD 2.3 schema.
Shape_Area	Area of feature in map units squared.	Double	True
Shape_Length	Length of the feature, which may differ from the field measured length due to differences in calculation. Units are map units.	Double	True		All features should have a positive integer value.
SourceDataDesc	SourceDataDesc is a space provided for a brief description of the type of base data used to update or change the current WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	True	100
SourceFeatureID	A long, unique code that identifies the parent of the feature if the feature is the result of a split or merge, and it is automatically generated and assigned.	Text	True	40
SourceOriginator	SourceOriginator is the description of the agency that created the base data used to improve the WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	False	130
States	The States or outlying area attribute identifies the State(s) or outlying areas that the hydrologic unit falls within or touches. The U.S. Census Bureau 1:100,000-scale State layer will be used to establish State boundaries in the derivation process.	Text	True	50	For WBD, indicates the states that contribute drainage to a hydrologic unit area.
TNMID	TNMID (short for The National Map Identification) is a unique 40-character field that identifies each element in the database exclusively.	Text	True	40
ToHUC	The 12-digit hydrologic unit ToHUC code attribute is the code for the 12-digit hydrologic unit that is downstream from and naturally receives the majority of the flow from another 12-digit hydrologic unit.	Text	True	16
VPUID	Vector Processing Unit Identifier. Found in NHDPlus HR only.	Text	True	8	This field only exists when NHD feature classes are brought into NHDPlus HR.

WBDHU14

A Comprehensive Aggregated Collection Of Hydrologic Unit Data Consistent With The National Criteria For Delineation And Resolution. The WBD Defines The Perimeters Of Drainage Areas (Hydrologic Units), Formed By The Terrain And Other Landscape Charactersitcs, At A 1:24,000 Scale In The United States, Except For Alaska At 1:63,360 Scale And 1:25,000 Scale In The Caribbean, And It Consists Of Digital Geographic Data That Include Six Levels Of Detailed Nested Hydrologic Unit Boundaries. WBDHU14 Represents The 14-Digit Hydrologic Unit Boundaries. This Hydrologic Unit Lacks A Common Name. WBDHU14 Is A New Subdivision In The WBD. Subdivisions At The 14-Digit Hydrologic Unit Are Not Required, But These Smaller Units Are Being Created To Support Specific Project Work At The Local Level. If They Are Created In Accordance With This Standard, They Will Be Included In The WBD.

Name	Definition	Type	Allow Nulls	Length	Comments
AreaAcres	AreaAcres is common to all polygon feature classes and is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, acreage values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the required projection to use for calculation.	Double	True
AreaSqKm	AreaSqKm is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, the square kilometer values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the default projection.	Double	True
GNIS_ID	GNIS_ID is a preassigned numeric field that uses a unique number to relate the name of the hydrologic unit to the GNIS names database. This field is automatically generated in the database.	Long Integer	False
HUC14	The HUC14 field is a unique 14-digit hydrologic unit code.	Text	True	14	This value is used in WBD and NHDPlus HR datasets. For NHDPlus HR, the hydrologic unit is used as a reference during NHDPlus HR data production.
HUMod	The 10-digit hydrologic unit modification attribute is a two-character, uppercase abbreviation(s) for either (1) the type of modification to natural overland flow that alters the natural delineation of a 10-digit hydrologic unit or (2) the special conditions GF-groundwater flow, GL-glacier, IF-ice field, KA-karst, and NC-noncontributing area.	Text	True	30	For HU polygons
HUType	The 14-digit hydrologic unit type attribute is the single-letter abbreviation for Subwatershed type from the list of official names.	Text	False	1	Has domain
LoadDate	LoadDate represents the date when the data were loaded into the official USGS WBD ArcSDE database. The field is the effective date for all feature edits, and it is automatically generated.	Date	False	22
MetaSourceID	A unique identifier that links the element to the metadata tables. This ID is generated and assigned automatically by the database and remains with the object permanently.	Text	True	40
Name	The 14-digit hydrologic unit name refers to the GNIS name for the geographic area in which the hydrologic unit is located.	Text	True	120
NonContributingAreaSqKm	Drainage area (SqKM) that does not contribute flow toward the outlet of a hydrologic unit.	Double	True
ReferenceGNIS_IDs	Comma delimited list of up to three GNIS_ID's identifying the hydrologic, geologic, or geographic features for which the Hydrologic Unit is named.	Text	True	50	New attribute for WBD 2.3 schema.
Shape_Area	Area of feature in map units squared.	Double	True
Shape_Length	Length of the feature, which may differ from the field measured length due to differences in calculation. Units are map units.	Double	True		All features should have a positive integer value.
SourceDataDesc	SourceDataDesc is a space provided for a brief description of the type of base data used to update or change the current WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	True	100
SourceFeatureID	A long, unique code that identifies the parent of the feature if the feature is the result of a split or merge, and it is automatically generated and assigned.	Text	True	40
SourceOriginator	SourceOriginator is the description of the agency that created the base data used to improve the WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	False	130
States	The States or outlying area attribute identifies the State(s) or outlying areas that the hydrologic unit falls within or touches. The U.S. Census Bureau 1:100,000-scale State layer will be used to establish State boundaries in the derivation process.	Text	True	50	For WBD, indicates the states that contribute drainage to a hydrologic unit area.
TNMID	TNMID (short for The National Map Identification) is a unique 40-character field that identifies each element in the database exclusively.	Text	True	40
ToHUC	The 14-digit hydrologic unit ToHUC code attribute is the code for the 14-digit hydrologic unit that is downstream from and naturally receives the majority of the flow from another 14-digit hydrologic unit.	Text	True	16	Has domain. Added to WBDHU14 for WBD 2.3 schema.

WBDHU16

A Comprehensive Aggregated Collection Of Hydrologic Unit Data Consistent With The National Criteria For Delineation And Resolution. The WBD Defines The Perimeters Of Drainage Areas (Hydrologic Units), Formed By The Terrain And Other Landscape Charactersitcs, At A 1:24,000 Scale In The United States, Except For Alaska At 1:63,360 Scale And 1:25,000 Scale In The Caribbean, And It Consists Of Digital Geographic Data That Include Six Levels Of Detailed Nested Hydrologic Unit Boundaries. WBDHU16 Represents The 16-Digit Hydrologic Unit Boundaries. This Hydrologic Unit Lacks A Common Name. This Is A New Subdivision In The WBD. Subdivisions At The 16-Digit Hydrologic Unit Are Not Required, But These Smaller Units Are Being Created To Support Specific Project Work At The Local Level. If They Are Created In Accordance With This Standard, They Will Be Included In The WBD.

Name	Definition	Type	Allow Nulls	Length	Comments
AreaAcres	AreaAcres is common to all polygon feature classes and is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, acreage values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the required projection to use for calculation.	Double	True
AreaSqKm	AreaSqKm is calculated at the hydrologic unit from the intrinsic area value maintained by the GIS software; therefore, the square kilometer values may vary from user calculations, depending on the projection of the data. North American Albers Equal Area Conic, North American Datum 1983 is the default projection.	Double	True
GNIS_ID	A permanent, unique number assigned by the Geographic Names Information System (GNIS) to a geographic feature name for the sole purpose of uniquely identifying that name application as a record in any information system database, dataset, file, or document	Text	True	10	GNIS_ID = "null" if no name is associated with the feature. Removed from WBD as of version 2.3 schema.
HUC16	The HUC16 field is a unique 16-digit hydrologic unit code.	Text	True	16	This value is used in WBD and NHDPlus HR datasets. For NHDPlus HR, the hydrologic unit is used as a reference during NHDPlus HR data production.
HUMod	The 10-digit hydrologic unit modification attribute is a two-character, uppercase abbreviation(s) for either (1) the type of modification to natural overland flow that alters the natural delineation of a 10-digit hydrologic unit or (2) the special conditions GF-groundwater flow, GL-glacier, IF-ice field, KA-karst, and NC-noncontributing area.	Text	True	30	For HU polygons
HUType	The 16-digit hydrologic unit type attribute is the single-letter abbreviation for Subwatershed type from the list of official names.	Text	False	1	Has domain
LoadDate	LoadDate represents the date when the data were loaded into the official USGS WBD ArcSDE database. The field is the effective date for all feature edits, and it is automatically generated.	Date	False	22
MetaSourceID	A unique identifier that links the element to the metadata tables. This ID is generated and assigned automatically by the database and remains with the object permanently.	Text	True	40
Name	The 16-digit hydrologic unit name refers to the GNIS name for the geographic area in which the hydrologic unit is located.	Text	False	120
NonContributingAreaSqKm	Drainage area (SqKM) that does not contribute flow toward the outlet of a hydrologic unit.	Double	True
ReferenceGNIS_IDs	Comma delimited list of up to three GNIS_ID's identifying the hydrologic, geologic, or geographic features for which the Hydrologic Unit is named.	Text	True	50	New attribute for WBD 2.3 schema.
Shape_Area	Area of feature in map units squared.	Double	True
Shape_Length	Length of the feature, which may differ from the field measured length due to differences in calculation. Units are map units.	Double	True		All features should have a positive integer value.
SourceDataDesc	SourceDataDesc is a space provided for a brief description of the type of base data used to update or change the current WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	True	100
SourceFeatureID	A long, unique code that identifies the parent of the feature if the feature is the result of a split or merge, and it is automatically generated and assigned.	Text	True	40
SourceOriginator	SourceOriginator is the description of the agency that created the base data used to improve the WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	False	130
States	The States or outlying area attribute identifies the State(s) or outlying areas that the hydrologic unit falls within or touches. The U.S. Census Bureau 1:100,000-scale State layer will be used to establish State boundaries in the derivation process.	Text	True	50	For WBD, indicates the states that contribute drainage to a hydrologic unit area.
TNMID	TNMID (short for The National Map Identification) is a unique 40-character field that identifies each element in the database exclusively.	Text	True	40
ToHUC	The 16-digit hydrologic unit ToHUC code attribute is the code for the 16-digit hydrologic unit that is downstream from and naturally receives the majority of the flow from another 16-digit hydrologic unit.	Text	True	16	Has domain. Added to WBDHU14 for WBD 2.3 schema.

WBDLine

Hydrologic Unit Boundaries Are Delineated And Digitized As Lines. The Digital Lines Are Processed By Using GIS Software To Form Polygons.

Name	Definition	Type	Allow Nulls	Length	Comments
HUDigit	HUDigit is a domain-based field that indicates the minimum number of digits used to represent the hydrologic unit bounded by the line.	Long Integer	True	24	This is for the line feature class, has domain
HUMod	The HUMod line modification attribute, completed by the WBD In-State Steward, is the two-character, uppercase abbreviation(s) code used to track either the modification to natural overland flow that alters the location of the hydrologic unit boundary or special conditions that are applied to a specific boundary line segment. The value identifies the type of modification, from the list provided, that has been applied to the boundary segment.	Text	False	20	This is for the line feature class
LineSource	LineSource represents the code for the base data usedfor delineating hydrologic unit boundaries.	Text	True	75	Updated to 75 characters for WBD 2.3 schema.
LoadDate	LoadDate represents the date when the data were loaded into the official USGS WBD ArcSDE database. The field is the effective date for all feature edits, and it is automatically generated.	Date	False	22
MetaSourceID	A unique identifier that links the element to the metadata tables. This ID is generated and assigned automatically by the database and remains with the object permanently.	Text	True	40
NHDPlusID	NHDPlus HR Unique identifier of a NHDFlowline feature. Found in NHDPlus HR Only.	Double	True		This field only exists when NHD feature classes are brought into NHDPlus HR.
NHDPlusID	NHDPlus HR Unique identifier of a NHDFlowline feature. Found in NHDPlus HR Only.	Double	True		This field only exists when NHD feature classes are brought into NHDPlus HR.
Shape	Feature geometry.	Geometry	True
Shape_Length	Length of the feature, which may differ from the field measured length due to differences in calculation. Units are map units.	Double	True		All features should have a positive integer value.
TNMID	TNMID (short for The National Map Identification) is a unique 40-character field that identifies each element in the database exclusively.	Text	True	40
VPUID	Vector Processing Unit Identifier. Found in NHDPlus HR only.	Text	True	8	This field only exists when NHD feature classes are brought into NHDPlus HR.

NWIS Drainage Area

Drainage Area As Reported By NWIS.

Name	Definition	Type	Allow Nulls	Length	Comments
AgencyCode	The code for the agency that reported the data to NWIS.	Text	True	5
AreaSqKm	Area of feature in square kilometers based on Albers Equal Area projection.	Double	True		Computed.
ContributingAreaSqMi	Drainage areas that contribute flow toward the outlet of a hydrologic unit, measured in square miles.	Double	True
GLOBALID	An ID that is generated by the geodatabase when database versioning is enabled in ArcSDE.		False
LoadDate	LoadDate represents the date when the data were loaded into the official USGS WBD ArcSDE database. The field is the effective date for all feature edits, and it is automatically generated.	Date	False	22
MetaSourceID	A unique identifier that links the element to the metadata tables. This ID is generated and assigned automatically by the database and remains with the object permanently.	Text	True	40
NWISContributingAreaSqMi	Drainage areas that contribute flow toward the outlet of a hydrologic unit, measured in square miles - text field.	Text	True	10
NWISTotalAreaSqMi	NWIS total drainage area for a site, measured in square miles - text field.	Text	True	10
ReferenceTNMIDNHDPointEvent	Reference The National Map National Hydrography Dataset Point Event ID	Text	True	40
remarks	Remarks for dataset.	Text	True	250
Shape	Feature geometry.	Geometry	True
Shape_Area	The size of the area in square decimal degrees. The values for this field are generated by ArcGIS. Primarily used in geodatabases.	Double	True
Shape_Length	The perimeter of the area in decimal degrees or the length of the feature in decimal degrees. The values for this field are generated by ArcGIS. Primarily used in geodatabases.	Double	True
SiteNumber	Unique 8- to 15-digit identification number for each site in the NWIS database.	Text	True	15
SourceDataDesc	SourceDataDesc is a space provided for a brief description of the type of base data used to update or change the current WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	True	100
SourceFeatureID	A long, unique code that identifies the parent of the feature if the feature is the result of a split or merge, and it is automatically generated and assigned.	Text	True	40
SourceOriginator	SourceOriginator is the description of the agency that created the base data used to improve the WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	False	130
StationName	Official station name for a site in NWIS.	Text	True	50
TNMID	TNMID (short for The National Map Identification) is a unique 40-character field that identifies each element in the database exclusively.	Text	True	40
TotalAreaSqMi	NWIS total drainage area for a site, measured in square miles.	Double	True

NWISDrainageLine

Drainage Area Boundary As Reported By NWIS.

Name	Definition	Type	Allow Nulls	Length	Comments
AgencyCode	The code for the agency that reported the data to NWIS.	Text	True	5
GLOBALID	An ID that is generated by the geodatabase when database versioning is enabled in ArcSDE.		False
LengthKM	Length of linear feature. Value is computed when data are in Albers Equal Area projection.	Double	True		Computed
LineSource	LineSource represents the code for the base data usedfor delineating hydrologic unit boundaries.	Text	True	75	Updated to 75 characters for WBD 2.3 schema.
LoadDate	LoadDate represents the date when the data were loaded into the official USGS WBD ArcSDE database. The field is the effective date for all feature edits, and it is automatically generated.	Date	False	22
MetaSourceID	A unique identifier that links the element to the metadata tables. This ID is generated and assigned automatically by the database and remains with the object permanently.	Text	True	40
Shape	Feature geometry.	Geometry	True
Shape_Length	The perimeter of the area in decimal degrees or the length of the feature in decimal degrees. The values for this field are generated by ArcGIS. Primarily used in geodatabases.	Double	True
SiteNumber	Unique 8- to 15-digit identification number for each site in the NWIS database.	Text	True	15
SourceDataDesc	SourceDataDesc is a space provided for a brief description of the type of base data used to update or change the current WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	True	100
SourceFeatureID	A long, unique code that identifies the parent of the feature if the feature is the result of a split or merge, and it is automatically generated and assigned.	Text	True	40
SourceOriginator	SourceOriginator is the description of the agency that created the base data used to improve the WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	False	130
TNMID	TNMID (short for The National Map Identification) is a unique 40-character field that identifies each element in the database exclusively.	Text	True	40

NonContributingDrainageArea

Drainage Areas That Do Not Contribute Flow Toward The Outlet Of A Hydrologic Unit.

Name	Definition	Type	Allow Nulls	Length	Comments
AreaSqKm	Area of feature in square kilometers based on Albers Equal Area projection.	Double	True		Computed.
GLOBALID	An ID that is generated by the geodatabase when database versioning is enabled in ArcSDE.		False
LoadDate	LoadDate represents the date when the data were loaded into the official USGS WBD ArcSDE database. The field is the effective date for all feature edits, and it is automatically generated.	Date	False	22
MetaSourceID	A unique identifier that links the element to the metadata tables. This ID is generated and assigned automatically by the database and remains with the object permanently.	Text	True	40
NonContributingAreaSqMi	Drainage areas that do not contribute flow toward the outlet of a hydrologic unit, measured in square miles.	Double	True
remarks	Remarks for dataset.	Text	True	250
Shape	Feature geometry.	Geometry	True
Shape_Area	The size of the area in square decimal degrees. The values for this field are generated by ArcGIS. Primarily used in geodatabases.	Double	True
Shape_Length	The perimeter of the area in decimal degrees or the length of the feature in decimal degrees. The values for this field are generated by ArcGIS. Primarily used in geodatabases.	Double	True
SourceDataDesc	SourceDataDesc is a space provided for a brief description of the type of base data used to update or change the current WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	True	100
SourceFeatureID	A long, unique code that identifies the parent of the feature if the feature is the result of a split or merge, and it is automatically generated and assigned.	Text	True	40
SourceOriginator	SourceOriginator is the description of the agency that created the base data used to improve the WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	False	130
TNMID	TNMID (short for The National Map Identification) is a unique 40-character field that identifies each element in the database exclusively.	Text	True	40

NonContributingDrainageLine

Drainage Lines That Do Not Contribute Flow Toward The Outlet Of A Hydrologic Unit.

Name	Definition	Type	Allow Nulls	Length	Comments
GLOBALID	An ID that is generated by the geodatabase when database versioning is enabled in ArcSDE.		False
LengthKM	Length of linear feature. Value is computed when data are in Albers Equal Area projection.	Double	True		Computed
LineSource	The code for the base data usedfor delineating hydrologic unit boundaries.	Text	True	30
LoadDate	LoadDate represents the date when the data were loaded into the official USGS WBD ArcSDE database. The field is the effective date for all feature edits, and it is automatically generated.	Date	False	22
MetaSourceID	A unique identifier that links the element to the metadata tables. This ID is generated and assigned automatically by the database and remains with the object permanently.	Text	True	40
Shape	Feature geometry.	Geometry	True
Shape_Length	The perimeter of the area in decimal degrees or the length of the feature in decimal degrees. The values for this field are generated by ArcGIS. Primarily used in geodatabases.	Double	True
SourceDataDesc	SourceDataDesc is a space provided for a brief description of the type of base data used to update or change the current WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	True	100
SourceFeatureID	A long, unique code that identifies the parent of the feature if the feature is the result of a split or merge, and it is automatically generated and assigned.	Text	True	40
SourceOriginator	SourceOriginator is the description of the agency that created the base data used to improve the WBD. The WBD In-State Steward completes this field as part of the metadata form.	Text	False	130
TNMID	TNMID (short for The National Map Identification) is a unique 40-character field that identifies each element in the database exclusively.	Text	True	40

MetaSourceDetail

Information specific to the source of the data, including the citation, data quality and metadata information.

Name	Definition	Type	Allow Nulls	Length	Domain
AttributeAccuracyReport	Explanation of entities and assignments of values in dataset.	Text	True	1800
BeginningDate	First year of the event (if Range_of_Dates applies).	Date	True	8
CalendarDate	The year (if Single Date applies).	Date	True	8
CompletenessReport	Information about omissions, criteria, definitions used to derive dataset.	Text	True	2400
Edition	The version of the title for the dataset (generally pertains to digital sources only).	Text	True	100
EndingDate	Last year for the event (if Range_of_Dates applies).	Date	True	8
HorizPositionalAccuracyReport	Horizontal coordinate measurements and description of tests used.	Text	True	3100
LogicalConsistencyReport	Explanation of fidelity of relationships in dataset and tests used.	Text	True	1000
MetadataDate	Date the metadata was last created or updated.	Date	True	8
MetadataStandardName	Name of the metadata standard used to document the dataset.	Text	True	100
MetadataStandardVersion	Identification of the version of the metadata standard used to document the dataset.	Text	True	40
MetaSourceID	A unique identifier that links the element to the metadata tables. This ID is generated and assigned automatically by the database and remains with the object permanently.	Text	True	40
OBJECTID	Internal feature or event number.	OBJECTID	False
PublicationDate	Date the dataset is published or made available for release.	Date	True
SeriesIssue	Information identifying the issue of the series publication of which the datset is a part (i.e. <specific map name>).	Text	True	200
SeriesName	The name of the series publication of which the data set is a part (i.e. USGS 1:24,000-scale topographic maps).	Text	True	200
SourceCitationAbbreviation	Short form alias for source citation.	Text	True	255
SourceContribution	Brief statement identifying the information contributed by the source to the datset.	Text	True	750
SourceCurrentnessReference	The basis on which the source time period of content information of the source data set is determined.	Text	True	255
SourceIDFieldName	The name of the attribute field that contains the globally unique and persistent identifier of an instance (for example: an instance of a feature or record) in the source data set. Note this is not the ObjectID, OID, FID fields which are auto-generated in ArcGIS.	Text	True	50
SourceOriginator	The name of an organization or individual that developed the dataset.	Text	True	130
SourceRefType		Long Integer	True		SourceRefType Domain
SourceScaleDenominator		Long Integer	True	4
SourceURL	The name of an online computer resource that contains the source of the dataset, for datasets with website or dataset (online) SourceRefTypes.	Text	True	100
Title	The name by which the dataset is known (generally pertains to digital sources only).	Text	True	100
VertPositionalAccuracyReport	Vertical coordinate measurements and description of tests used.	Text	True	3100

MetaProcessDetail

Table with information specific to the processor (contact information) and the process used in loading or updating the dataset features or objects.

Name	Definition	Type	Allow Nulls	Length	Domain	Comments
Address	Address line for the address.	Text	True	100
City	City of the address.	Text	True	40
ContactEmailAddress	E-mail address to reach contact organization or individual.	Text	True	40
ContactInstructions	Supplemental instructions to contact Organization or individual.	Text	True	120
ContactOrganization	Name or organization to which type of contact applies.	Text	True	100
ContactURL	The address of a resource on the internet (i.e., a website address) for the contact organization or individual that is associated with loading or updating the data.	Text	True	100
ContactVoiceTelephone	Telephone number to reach Organization or individual.	Text	True	40
DataSetCredit	Recognition of those who contributed to the dataset.	Text	True	4000
EditType	A description of the type of edit made.		True	4	EditType Domain
LoadDate	Date and time feature or event was loaded into the database. Timestamp indicating when the feature or event was last edited.		True	8
MetaProcessID	Unique ID for a metadata process description.	Text	False	40		Features are associated to specific process descriptions. The Meta_ProcessID links to the NHDMetadata table.
OBJECTID	Internal feature or event number.	OBJECTID	False
PostalCode	ZIP or other postal code of the address.	Text	True	20
ProcessDate	Date when the event was completed.		False	8
ProcessDescription	Explanation of the event and related parameters or tolerances.	Text	False	4000
StateOrProvince	State or province of the address.	Text	True	30

FeatureToMetadata

Table that links the features / objects to one or more processes and their sources. This table gives the model the capability of lineage or the capability of tracking the history of changes for a given feature.

Name	Definition	Type	Allow Nulls	Length	Comments
MetaProcessID	Unique ID for a metadata process description.	Text	False	40	Features are associated to specific process descriptions. The Meta_ProcessID links to the NHDMetadata table.
OBJECTID	Internal feature or event number.	OBJECTID	False
TNMID	TNMID (short for The National Map Identification) is a unique 40-character field that identifies each element in the database exclusively.	Text	True	40

ExternalCrosswalk

Contains associations of Permanent_Identifiers to external source Identifiers.

Name	Definition	Type	Allow Nulls	Length
ExternalID	ID that identifies the feature in the source dataset.	Text	True	40
ExternalIDEntryDate	Load date of the ExternalID record.	Date	True
ExternalIDName	Field name in the external source dataset that contains the unique IDs.	Text	True	50
ExternalIDOriginator	Name of the organization or individual who developed the external dataset/features.	Text	True	130
OBJECTID	Internal feature or event number.	OBJECTID	False
OrganizationType	Administrative level code of the organization or individual who developed the external dataset/features.	Long Integer	True
Permanent_Identifier	A 40-character globally unique ID (GUID) value that uniquely identifies the occurrence of each feature or event in The National Map.	Text	False	40