The NHD assigns names to water features as they are depicted in the Geographic Names Information Service (GNIS), which is maintained by the Bureau of Geographic Names (BGN). In July 2011, Division of Water began an extensive audit of the GNIS names and ID codes used in the NHD. The audit is done as part of a sub-basin’s maintenance cycle and consists of these steps:
- Assigning the proper GNIS name and ID code to any NHD Feature which lacks this data.
- Checking the NHD Flowline feature class to verify the correct stream reaches are identified. In the event the headwaters stream carrying the GNIS data does not match the GNIS database, the following steps are taken:
- The GNIS data is transferred to the headwaters stream indicated by the GNIS database.
- New reach codes are assigned as necessary.
- In the event the GNIS name and/or ID code do not match, the NHD is updated to use the name and/or ID code used in the most recent GNIS database extract.
- In the event potential mistakes in a GNIS record are discovered, these are immediately reported to the BGN.
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