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RAD
Managed NHD Supplemental Tables
WATERS services and RAD programs often require NHD data to be
reformatted into more usable and better performing data
structures. These table resources are available to developers and
internal EPA users for usage in their own applications.NHDFLOWLINE_ST_OS
NHDWATERBODY_ST_OS
Primary Consumer: Total Waters Service
The specification of the total waters service requires the ability to tally the spatial extent of RAD programs by state, HUC and NHD fcode. As NHD hydrography does not respect state boundaries, new layers were created to better allocate hydrologic features to states. As many feature cross state boundaries, these features - known as "border waters" were coded specially to show shared ownership. This allows totals of a given state to either exclude border waters, include just those portions of border waters assigned to the state, or include the entirety of the border water.
Field Name
Data Type
NULL?
Description
comid
NUMBER(11) N
Unique numeric identification number for the feature as assigned by the USGS. Note this value cannot be used as the primary key as a single NHD flowline may be divided into several records though interaction with state borders.
fdate
DATE
N
The NHD feature date of the original feature.
resolution
INTEGER
N
Numeric USGS value indicating the resolution of the feature: 3 = medium, 2 = high, 1 = local. gnis_id
VARCHAR2(10)
Y
USGS Geographic Names Information System defined identification code for the original NHD feature.
gnis_name
VARCHAR2(99)
Y
USGS Geographic Names Information System fl_lengthkm
NUMBER(11,3)
N
The length of the original NHD flowline in KM.
reachcode
VARCHAR2(14)
N
The reach code of the original nhdflowline.
flowdir
VARCHAR2(15)
N
The flow direction value of the original NHD flowline.
wbareacomi
NUMBER(11)
Y
The waterbody comid of any NHD waterbodies intersecting the original NHD flowline.
wb_fcode
NUMBER(5)
Y
The fcode value of any NHD waterbody intersecting the original NHD flowline.
ftype
VARCHAR2(24)
N
The feature type of the original NHD flowline.
fcode
NUMBER(5)
N
The feature code of the original NHD flowline.
f_meas
NUMBER(12,4)
N
The reach "from" measure for the flowline represented in the record.
t_meas
NUMBER(12,4)
N
The reach "to" measure for the flowline represented in the record. enabled
VARCHAR2(6)
Y
Unused field.
fl_seg_lengthkm
NUMBER(11,3)
N
The length of the possibly clipped flowline represented in the record in KM.
rch_lengthkm
DATE
N
The complete length of the reach to which this flowline belongs in KM.
st
VARCHAR2(2)
N
The state to which the possibly clipped NHD flowline has been assigned.
st_name
VARCHAR2(90)
N
The name of the state to which the possibly clipped NHD flowline as been assigned.
assigned_st
VARCHAR2(2)
N
The code indicating states which share ownership over the original NHD flowline
uniq_id
NUMBER
N
Unique identification number assigned to all state-based flowlines.
inter_flag
VARCHAR2(3)
Y
Flag used to indicate if a feature is entirely within a state geometry or intersecting any boundaries of state geometries.
shape
MDSYS. SDO_GEOMETRY
Y
Geometry of the possibly clipped flowline represented in the record.
objectid
INTEGER
N
Unique numeric key used by ArcSDE. Note this number is not constant and may change as a result of maintenance.
Field Name
Data Type
NULL?
Description
comid
NUMBER(11) N
Unique numeric identification number for the feature as assigned by the USGS. Note this value cannot be used as the primary key as a single NHD waterbody may be divided into several records though interaction with state borders.
fdate
DATE
N
The NHD feature date of the original feature.
resolution
INTEGER
N
Numeric USGS value indicating the resolution of the feature: 3 = medium, 2 = high, 1 = local. gnis_id
VARCHAR2(10)
Y
USGS Geographic Names Information System
gnis_name
VARCHAR2(99)
Y
USGS Geographic Names Information System reachcode
VARCHAR2(14)
N
The reach code of the original NHD waterbody.
areasqkm
NUMBER(11,3)
N
The area in square KM of the original NHD waterbody.
elevation
NUMBER(11,3)
Y
The elevation of the original NHD waterbody.
ftype
VARCHAR2(24)
N
The feature type of the original NHD waterbody.
fcode
NUMBER(5)
N
The feature code of the original NHD waterbody. wb_sub_areasqkm
NUMBER(18,3)
N
The area in square KM of the possibly clipped waterbody represented by the record.
rch_areasqkm
NUMBER(18,3)
N
The area in square KM of the reach to which the original waterbody belongs. st
VARCHAR2(2)
N
The state to which the possibly clipped NHD waterbody has been assigned.
st_name
VARCHAR2(90)
N
The name of the state to which the possibly clipped NHD waterbody as been assigned.
assigned_st
VARCHAR2(2)
N
The code indicating states which share ownership over the original NHD flowline
uniq_id
NUMBER
N
Unique identification number assigned to all state-based waterbodies.
inter_flag
VARCHAR2(3)
Y
Flag used to indicate if a feature is entirely within a state geometry or intersecting any boundaries of state geometries.
shape
MDSYS. SDO_GEOMETRY
Y
Geometry of the possibly clipped flowline represented in the record.
objectid
INTEGER
N
Unique numeric key used by ArcSDE. Note this number is not constant and may change as a result of maintenance.
code
NHDFLOWLINE_REACHES
NHDWATERBODY_REACHES
Primary Consumer: Event Indexing Service and Event Maintenance
The current NHD data model abstracts the concept of the reach so that examining the reach as an entity requires aggregating flowlines or waterbodies together for reach analysis. This can create significant performance issues for services. These tables provide in tabular format a list of all valid reaches and a few calculated attributes aiding analysis.
Field Name
Data Type
NULL?
Description
reachcode
VARCHAR2(14) N
Unique reach codes taken from the nhdflowline table.
waterbodies
INTEGER
N
Numeric count of all NHD waterbodies intersecting this linear reach.
reachsmdate
DATE
N
The reachsmdate for the feature as derived from the nhdreachcode_comid table. Provided here to reduce the requirement to query multiple tables during service processing.
Field Name
Data Type
NULL?
Description
reachcode
VARCHAR2(14) N
Unique reach codes taken from the nhdwaterbody table. artificial_paths
INTEGER
N
Numeric count of all NHD flowlines intersecting this area reach.
reachsmdate
DATE
N
The reachsmdate for the feature as derived from the nhdreachcode_comid table. Provided here to reduce the requirement to query multiple tables during service processing.
code
NHDFLOWLINE_NODES_OS
Primary Consumer: Event Indexing Service
A specialized feature of the indexing service uses spatial analysis to traverse the NHD flowlines between two points. This process is greatly aided by having a table of "nodes" representing the "from" and "to" end points of each flowline.
code
Field Name
Data Type
NULL?
Description
comid
NUMBER(11) N
Unique numeric identification number for the feature as assigned by the USGS. endpoint
VARCHAR2(5) N
Keywords "START" or "END" indicating the endpoint represented by the record.
reachcode
VARCHAR2(14) N
Reach codes to which the flowline belongs.
fcode
NUMBER(5)
N
The feature code of the NHD flowline. measure
NUMBER(12,4)
N
The reach measure at which the node occurs.
lengthkm
NUMBER(11,3)
N
The total length of the flowline on which the node occurs.
shape
MDSYS.
SDO_GEOMETRY
Y
The point geometry of the node.