Be Aware of what USGS is up to.

[joewheaton]

For the US implementation of our riverscape network models, we rely heavily (in first instance on NHD). As such, all the @Riverscapes/developers should have a read of the latest.

Elevation-Derived Hydrography Acquisition Specifications:

If you have not already seen the USGS's Terziotti & Archuleta (2020), any of the @Riverscapes/developers should have a read:

• Terziotti S, Archuleta CM. 2020. Elevation-Derived Hydrography Acquisition Specifications: U.S. Geological Survey Techniques and Methods. In Book 11, Collection and Delineation of Spatial Data , U.S. Geological Survey: Reston, VA; 74. [online] Available from: https://doi.org/10.3133/tm11B11

It provides a really helpful update on where the USGS is at with brining on 3DEP to update the NHD networks and where and how discrepancies arise between the origianl NHDFlowlines and elevation-derived hydrography:

This will have a lot of relevance as we move forward in the future and leverage these to run "New Channel Area" projects.

They also help explain the source of drainage density disparities between 1:24,000 topo map boundaries:

Elevation-Derived Hydrography—Representation, Extraction, Attribution, and Delineation Rules

• Archuleta CM, Terziotti S. 2020. Elevation-Derived Hydrography—Representation, Extraction, Attribution, and Delineation Rules. In Book 11, Collection and Delineation of Spatial Data , 60. https://doi.org/10.3133/tm11B12
  

They explain for all the FCodes and feature types what are the rules for how they delineate features: