Confluence RetirementDue to the feedback from stakeholders and our commitment to not adversely impact USGS science activities that Confluence supports, we are extending the migration deadline to January 2023.
FROM NHDPLUSV2 User Guide:
Catchment The incremental drainage area for a linear hydrologic feature found in the National Hydrography
Flowline A mapped stream segment or a path through a waterbody in the surface-water network of the National
Hydrography Dataset. The basic unit of the NHD linear surface-water network.
Reach (also NHD Reach) A uniquely identified linear feature that consists of one or more flowlines.
Stream segment (also see flowline) Part of a stream, often extending between tributary confluences
Stream spatial network terminology used in discussion points (based on Figure below)
= Stream reach, typically defined as a stream segment connecting 2 of the following; stream origins, stream confluences, lake or reservoir inflows or outflows, and/or stream outflows
Yellow = 90 meter buffer of stream
Blue Polygon = Local Catchment, catchment draining to an individual stream reach
Green Polygon = Upstream Drainage Catchment, upstream drainage of a given reach NOT including the local catchment
Green Polygon + Blue Polygon = Network Catchment, entire upstream drainage of a given reach including the local catchment
Figure borrowed from NFHP’s 2015 Through A Fish’s Eye Report
Summarization of information to local catchment is called Attribution (MSU and NAQWA) or Allocation (StreamCAT and NHDPlus).
Summarization of information to network catchments is called Aggregation (MSU and NAQWA) or Accumulation (StreamCAT and NHDPlus)