----------------------- 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 :doc:`examples `. .. _flopy.discretization.Grid`` instance`: https://aleaf.github.io/sfrmaker/usage.html#create-a-flopy-structuredgrid-instance-defining-the-model-grid .. _NHDPlus v2 hydrography datasets: http://www.horizon-systems.com/NHDPlus/NHDPlusV2_data.php .. _via a shapefile: https://aleaf.github.io/sfrmaker/usage.html#alternatively-the-model-grid-can-be-defined-with-a-sfrmaker-structuredgrid-instance