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RAD Data Model

The Reach Address Database (RAD) stores reach address information for each Water Program feature that has been linked to the underlying surface water features (streams, lakes, etc) in the National Hydrology Database (NHD) Plus dataset. These reach addresses record the geographic extent of Water Program features in both tabular and spatial formats.

The RAD only contains reach address information. Additional feature level attribute information is stored in separate Water Program databases. A unique Water Program feature ID is used to relate the reach address for each Water Program feature found in the RAD with the other detailed data for that feature found in the separate databases. This unique Water Program feature ID is also called the Source Feature ID. The Water Program feature ID is the key for relating the event tables and shapefiles with the corresponding attribute information for that feature.

The Reach Address Database (RAD) data model is closely related to the NHD Event Data Model with some extensions added to track supplemental attribute data. A RAD program may store two sets of event data - the current RAD program event data and an archive of previous program event data.

Each RAD event is comprised of several records that tie together in the following manner:

Basic RAD Event

  • Source Feature ID:
    Each RAD event comprises all or part of a parent source feature id. Source feature id values match to attribute data stored in Water Program Databases. This table lists each unique source feature id, source_originator and start_date in the current RAD dataset along with summarized statistics for all events comprising the set. For program utilizing cycle information, the cycle_year field may replace start_date in the model.

  • Event Tables:
    A RAD event is defined as any combination of point, line or area events. Point and line events describe observations occurring along NHD flowline features and area events describe observations occurring upon NHD waterbody features.

  • Event to Metadata:
    The event to metadata record ties together the event geometry record with its metadata record(s). This table exists to allow the model to accommodate multiple metadata records for each event geometry record.

  • Event Metadata:
    Event metadata tracks critical information about the submitter of the event and how the event was spatially determined. Note that the metadata record does not contain information about the particulars of the source feature id. This must be obtained from the Water Program Databases.

  • Event Source Citation:
    Source Citation metadata tracks information about one or more specific sources used in combination to create an event record. Each event metadata record may have zero or more source citation records.

RAD Source Feature IDs

Field Name
Data Type
NULL?
Description
Source_FeatureID
String 100
N
Identifier of the entity used in the source data.
Source_Originator
String 130
N
Originator of the event.
Start_Date
Date
N
The date by which the event first is considered to be valid.
Cycle_Year
String 4 Y
Optional field indicating a year for which the event is considered to be valid. Only a subset of programs track events via cycle year.
Event_Count
Integer
Y
Total count of all events.
Load_Date Date Y Initial date the source feature ID was loaded into the reach address database. This represents the date of data processing and has no reflection on the vintage of the events themselves which are expressed through EventDate, Start_Date and Cycle_Year.
Update_Date Date Y Optional date tracking any subsequent updates to the source feature ID.
Loader_ID String 256 Y ID of the authority submitting the source feature ID to the reach address database. This represents the agent doing the indexing and submitting the data through EPA's CDX gateway and does not represent the source of the data which is designated via the Source Originator field.
Total_Points Integer Y Total count of all point events participating in the Source Feature ID.
Total_LengthKM Double Y Total length in kilometers of all line events participating in the Source Feature ID.
Total_AreaSqKm Double Y Total area in square kilometers of all area events participating in the Source Feature ID.
ObjectID
Integer
N
Unique numeric key.

RAD Point Events

Field Name
Data Type
NULL?
Description
Permanent_Identifier String 40 N 40-char GUID value that uniquely identifies the occurrence of each event.
EventDate
Date
Y
Date an event was created.
ReachCode
String 14
Y
Reach Code on which the event is located.
ReachSMDate
Date
Y
Reach Version Date.
ReachResolution
Integer
Y
Source resolution. See NHD Resolution Domain Table for the list of possible values.
Feature_Permanent_Identifier String 40 Y Permanent_Identifier of NHD feature that is referenced as an event.
FeatureClassRef Integer Y Domain value identifying the type of feature referenced in Feature_Permanent_Identifier. See NHD Feature Class Reference Domain Table for the list of possible values.
Source_Originator
String 130
N
Originator of the event.
Source_DataDesc
String 100
Y
Description of the entity.
Source_FeatureID
String 100
N
Identifier of the entity used in the source data.
FeatureDetailURL
String 255
Y
URL where detailed event entity data can be found.
Measure
Double
Y
Measure along the reach, in percent from downstream end, where a point event is located.
EventOffset Double Y Distance from the network to be used to display event. Negative offsets display the event to the left of the network and positive offsets display the event to the right of the line. Offsets are useful for displaying overlapping events.
EventType Integer N Domain value indicating the program for which the event has been created. See RAD Programs for values of each program.
GeogState
String 2
N
Abbreviation of the state where the event takes place regardless of the source originator. In most cases this will be the same as source_originator, but they may differ in cases such that tribes, state cooperators, and other non-state specific organizations manage the data. This distinction allows for both state based and management-based analysis
Cycle_Year
String 4 Y
Optional field indicating a year for which the event is considered to be valid. Only a subset of programs track events via cycle year.
Start_Date
Date
Y
The date by which the event first is considered to be valid.
End_Date
Date
Y
The date by which the event is considered to be closed.
WBD_HUC12
String 12
Y
WBD HUC12 unit that most encompasses the NHD feature.
WBD_HUC12_Percent
Double
Y
Percentage of the feature contained within the WBD HUC12 unit.
Navigable String 1 N Y/N flag indicating whether an event exists upon NHD flowline features with NHDPlus flow information. Mainly utilized by mapping services to either display or not display a navigation interface for a given event.
Vertices
Integer
Y
Numeric count of individual vertices in the event record geometry.
Shape
Geometry
Y
Geometry object holding geodetic NAD83 spatial representation of the event.
ObjectID
Integer
N
Vendor-required unique numeric key.

RAD Line Event

Field Name
Data Type
NULL?
Description
Permanent_Identifier String 40 N 40-char GUID value that uniquely identifies the occurrence of each event.
EventDate
Date
Y
Date an event was created.
ReachCode
String 14
Y
Reach Code on which the event is located.
ReachSMDate
Date
Y
Reach Version Date.
ReachResolution
Integer
Y
Source resolution. See NHD Resolution Domain Table for the list of possible values.
Feature_Permanent_Identifier String 40 Y Permanent_Identifier of NHD feature that is referenced as an event.
FeatureClassRef Integer Y Domain value identifying the type of feature referenced in Feature_Permanent_Identifier. See NHD Feature Class Reference Domain Table for the list of possible values.
Source_Originator
String 130
N
Originator of the event.
Source_DataDesc
String 100
Y
Description of the entity.
Source_FeatureID
String 100
N
Identifier of the entity used in the source data.
FeatureDetailURL
String 255
Y
URL where detailed event entity data can be found.
FMeasure
Double Y
Measure along the reach, in percent from downstream end, where a linear event begins (from).
TMeasure
Double
Y
Measure along the reach, in percent from downstream end, where a linear event ends (to).
EventOffset Double Y Distance from the network to be used to display event. Negative offsets display the event to the left of the network and positive offsets display the event to the right of the line. Offsets are useful for displaying overlapping events.
EventType Integer N Domain value indicating the program for which the event has been created. See RAD Programs for values of each program.
Event_LengthKm
Double
N
Length of the linear event in kilometers.
GeogState
String 2
N
Abbreviation of the state where the event takes place regardless of the source originator. In most cases this will be the same as source_originator, but they may differ in cases such that tribes, state cooperators, and other non-state specific organizations manage the data. This distinction allows for both state based and management-based analysis.
Cycle_Year
String 4 Y
Optional field indicating a year for which the event is considered to be valid. Only a subset of programs track events via cycle year.
Start_Date
Date
Y
The date by which the event first is considered to be valid.
End_Date
Date
Y
The date by which the event is considered to be closed.
WBD_HUC12
String 12
Y
WBD HUC12 unit that most encompasses the NHD feature.
WBD_HUC12_Percent
Double
Y
Percentage of the feature contained within the WBD HUC12 unit.
Navigable String 1 N Y/N flag indicating whether an event exists upon NHD flowline features with NHDPlus flow information. Mainly utilized by mapping services to either display or not display a navigation interface for a given event.
Vertices
Integer
Y
Numeric count of individual vertices in the event record geometry.
Shape
Geometry
Y
Geometry object holding geodetic NAD83 spatial representation of the event.
ObjectID
Integer
N
Vendor-required unique numeric key.

RAD Event to Metadata

Field Name
Data Type
NULL?
Description
Permanent_Identifier String 40 N 40-char GUID value that uniquely identifies the occurrence of each event.
Meta_ProcessID String 40 N 40-char GUID value that uniquely identifies a metadata process description.
ObjectID
Integer
N Vendor-required unique numeric key.

RAD Metadata

Field Name
Data Type
NULL?
Description
Meta_ProcessID String 40 N 40-char GUID value that uniquely identifies a metadata process description.
ProcessDescription
String 4000
N
Explanation of the event and related parameters or tolerances.
ProcessDate
Date
N
Date when the data was completed.
AttributeAccuracyReport String 1800 Y Explanation of entities and assignments of values in dataset.
LogicalConsistencyReport String 1000 Y Explanation of fidelity and relationships in dataset and tests used.
CompletenessReport String 2400 Y Information about omissions, criteria, definitions used to derive dataset.
HorizPositionalAccuracyReport String 3100 Y Horizontal coordinate measurements and description of test used.
VertPositionalAccuracyReport String 3100 Y Vertical coordinate measurements and description of test used.
MetadataStandardName String 100 Y Name of the metadata standard used to document the dataset.
MetadataStandardVersion String 40 Y Identification of the version of the metadata standard used to document it.
MetadataDate Date Y Date the metadata was last created or updated.
DatasetCredit String 4000 Y Recognition of those who contributed to the dataset.
ContactOrganization
String 100
Y
Name or organization to which type of contact applies.
AddressType
String 40 Y
Information provided about the address, i.e. mailing, physical, etc.
Address
String 100
Y
Address line for the address.
City
String 40
Y
City of the address.
StateOrProvince
String 30
Y
State or province of the address.
PostalCode
String 20
Y
ZIP or other postal code of the address.
ContactVoiceTelephone
String 40
Y
Telephone number to reach organization or individual.
ContactInstructions
String 120
Y
Supplemental instructions to contact organization or individual.
ContactEmailAddress
String 40
Y
Email address to reach organization or individual.
ObjectID
Integer
N
Vendor-required unique numeric key.

RAD Source Citation

Field Name Data Type NULL? Description
Source_DatasetID String 40 N Unique permanent ID value which uniquely identifies a source dataset used.
Title String 255 Y Name by which the dataset is known.
SourceCitationAbbreviation String 255 Y Short form alias for source citation.
Originator String 400 Y Name of organization or individual who developed the dataset.
PublicationDate Date Y Date the dataset is published or made available for release.
BeginningDate Date Y First year of the event (if range of dates applies).
EndingDate Date Y Last year of the event (if range of dates applies).
SourceContribution String 255 Y Brief statement identifying information contributed by source to dataset.
SourceScaleDenominator Integer Y Denomination of representative fraction on a map.
TypeOfSourceMedia String 255 Y The medium of the source dataset, i.e. paper, CD-ROM, online, etc.
CalendarDate Date Y The year (if single date applies).
SourceCurrentnessReference String 255 Y Source time period of content information of source dataset is determined.
Meta_ProcessID String 40 N 40-char GUID value that uniquely identifies a metadata process description.
ObjectID Integer N Vendor-required unique numeric key.

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