Input data requirements

1) Hydrography data

NHDPlus v2 hydrography datasets

Archives needed/relevant files:

NHDPlusV21_XX_YY_NHDSnapshot_*.7z

  • NHDFcode.dbf

  • NHDFlowline.dbf, .prj, .shp, .shx

NHDPlusV21_XX_YY_NHDPlusAttributes_*.7z

  • elevslope.dbf

  • PlusFlow.dbf

  • PlusFlowlineVAA.dbf

Notes:

XX is Drainage Area ID (e.g., GL for Great Lakes) and YY is the Vector Processing Unit (VPU; e.g. 04) in the above (see NHDPlus website for details).

Custom hydrography

Any Polyline shapefile can be supplied in lieu of NHDPlus, but it must have the following columns, as shown in the second example:

  • flowlines_file: path to shapefile

  • id_column: unique identifier for each polyline

  • routing_column: downstream connection (ID), 0 if none

  • width1_column: channel width at start of line, in attr\_length\_units (optional)

  • width2_column: channel width at end of line, in attr_length_units (optional)

  • up_elevation_column: streambed elevation at start of line, in attr_height_units

  • dn_elevation_column: streambed elevation at end of line, in attr_height_units

  • name_column: stream name (optional)

  • attr_length_units: channel width units

  • attr_height_units: streambed elevation units

2) Model grid information

is supplied by creating a `flopy.discretization.Grid instance`_, instance or via a shapefile, as shown in the examples.