NHD Flowlines consist of routes that make up a linear surface water drainage network. Flowlines have a reach code and a measure, allowing for the establishment of upstream/downstream relationships. This network allows for powerful analysis and modeling capabilities. Each Feature type is attributed with descriptive information by an Fcode.
The NHD was created to assist scientists in modeling hydrologic features and is also useful for cartographic mapping purposes. The geometric features that came from the USGS DLG files, combined with the flow direction, reach codes, and other attributes taken from the EPA RF3 file, make the NHD a powerful modeling tool.
USGS, Florida Water Management Districts, Florida Department of Environmental Protection
Florida Department of Environmental Protection
hydrography, water, lakes, streams, rivers, estuaries
Estimated to meet 1:24,000 National Map Accuracy Standards (+/- 40 feet)
If the source for elevation is 7.5 minute topo map, estimated to be one half of a contour, or +/- 2.5 feet.
ESRI File Geodatabase
Albers Florida HARN
permanent_identifier = Unique ID
fdate = Date of last feature modification.
resolution = Source resolution. All values = 2
gnis_id = USGS Geographic Names Information System (GNIS) ID
gnis_name = USGS Geographic Names Information System (GNIS) Name
reachcode = Unique identifier composed of two parts. The first eight digits is the subbasin code as defined by FIPS 103. The next six digits are randomly assigned, sequential numbers that are unique within a subbasin, length 14.
flowdir = Direction of flow relative to coordinate order.
ftype = 3-digit feature code. (Integer)
|460||Stream / River|
fcode = 5-digit feature code. Extra two digits provide a more detailed description of the feature. (Integer)
enabled = Created when Geometric Network is built. All features should be set to True. New or modified features will have a Null value until network is rebuilt.