North Dakota Watershed Boundary Dataset Update

There have been a few updates to the North Dakota WBD that is distributed on the ND GIS Hub Data Portal.  First, the field HULEVEL in the HUC12_Line feature dataset will no longer maintained.  This field was only maintained in the state WBD and does not exist in the national WBD.  HULEVEL field is similar to the already existing HUDIGIT and conveys similar meaning, specifically what hydrologic unit level the line represents: 10-digit, 12-digit, 4-digit, etc.  Below is a table of HUDIGIT labels and values that can be used to symbolize the HUC12_Line feature dataset:

Label                              Value
12-digit Hydrologic Unit 12
10-digit Hydrologic Unit 10
8-digit Hydrologic Unit            8
6-digit Hydrologic Unit            6
4-digit Hydrologic Unit            4
2-digit Hydrologic Unit            2

14-digit and 16-digit hydrologic units have a value of "14" and "16", respectively and are nested within the 12-digit hydrologic units.  However, there are no 14-digit or 16-digit hydrologic units delineated for North Dakota at this time. 

Second, some field names have changed slightly from what was on the ND GIS Hub previously to make them consistent with what is in the national WBD.  The records contained in these attribute fields remain the same, just the field names have changed. MetasourceID, SourceDataDesc, SourceOriginator, and SourceFeatureID are the fields that now have the same name as the national dataset. 

Lastly, linework and coding updates have been made in the following areas:

• HU12 hydrologic unit lines and codes have been added to the Canadian portion of the Lower Red basin.  
• HUC12 linework adjustments have been made near selected confluences across the state to align WBD polygons to NHD streamlines, flowlines and pour points when appropriate. 
• Revisions have been made throughout the dataset as part of a nationwide effort to review linework, verify HU codes, downstream codes as well as a comprehensive review of hydrologic unit names to bring older delineations up to the current standards.  

The WBD delineation effort for the U.S. spanned more than 15 years. In North Dakota, delineation efforts began in 1999 and were not certified complete until 2008.  In those nine years alone, North Dakota hydrologists and GIS specialists followed three different versions of the Federal WBD Delineation Standards.  We now believe we have a stable Federal WBD Delineation Standard so large-scale updates like these should not be as frequent as they have in the past. In North Dakota, harmonization across the US-Canada border has also been completed.  Users should still be aware that updates will periodically occur. Be sure to check the publication date in the metadata to make sure you have the most recent data available. The WBD that is distributed on the USGS WBD download site (https://nhd.usgs.gov/wbd.html) is refreshed monthly to account for nationwide stewardship activity.  WBD data distributed on the ND GIS Hub Data Portal will be updated twice per year.   If you have any questions about the WBD, please contact the ND WBD Data Steward, Ann Fritz at afritz@nd.gov or the U.S. Geological Survey WBD Team Lead, Kimberly Jones, kjones@usgs.gov.