Post Development Grid Modification

This section outlines a process to port data after the domain has been changed or the grid elements size has been changed. The process will be outlined based on the available layers and procedures in the QGIS FLO-2D Plugin order. If the user data does not have a section below, skip that bullet.

• Computational Domain Layer

  • Update polygon to cover complete project extent.

  • Set cell size.

• Grid

  • Create the grid.

• Interpolate Elevation

  • Import full coverage raster.

    • If a new area is needed, it is easy to create a mosaic of the two rasters.

    • Export the grid layer as a raster and use a mosaic tool to combine the two rasters.

    • It is a good idea to use the new grid element resolution and alignment as the extent and size for the raster.

  • Sample full coverage raster with the Sampling grid elevation from raster layer.

• Roughness

  • Recalculate from a full coverage shapefile.

  • If shapefile is not available,

    • Export the old grid and intersect it with roughness polygons for the new grid.

    • Use a Dissolve tool to simplify the shapefile so it combines like polygons with the same n-value.

• Buildings

  • Recalculate from Blocked Areas layer.

  • It may be necessary to add buildings from additional area.

• Extra Grid features

  • Run separate tools for Spatial Tol, Spatial Froude, Spatial Shallow n, and Gutters.

• Infiltration

  • Recalculate from external layers.

  • It may be necessary to add infiltration areas to the infiltration shapefile.

    • If extra data is needed, intersect the new data into the Soil and Landuse shapefiles.

• Hydraulic Structures

  • Copy polyline features from Structures Schematic Layer.

  • Paste into Structures User Layer.

  • Run structures schematize tool to refresh data.

  • Add new structures using the editor tool and table editor after refreshing the data.

  • Rerun schematize tool to add new data to final Schematic Layer.

• Levees

  • If User Layers Levee Lines are available, use them to recalculate the levees.

  • If Levee Lines User Layer is not present, use this simple process to copy them from the Schematized Levees. (This does not work for walls)

    • Create levee lines the center of the levee. This is just the standard create levee polyline using the editor add polyline process.

    • Make certain these lines cross the Schematic Levees frequently.

    • Intersect the Levee Lines Layer and Levees Layer to generate a point file with crest elevation.

    • Copy that to the Elevation Points Layer.

    • Run the Levee Calc tool with Levee Lines and Points.

    • The idea is to intersect the schema lines and get the crest elevation for the points layer.

  • Walls

    • Recalculate walls from wall data.

• Boundary Conditions

  • Run schematize button.

  • The downstream boundary might need to be edited or repositioned.

• Rain

  • Rerun depth Area Reduction sampler if used.

• Save and export data.

• Channels

  • Rerun schematize.

  • Export .DAT files.

  • Run Interpolator.

  • Import interpolated channels.

  • It may be necessary to make left and right bank alignment corrections.

• Floodplain cross sections

  • Rerun schematize.

  • It may be necessary to add new cross sections.

• Storm Drain

  • Add new data to the storm drain shapefiles.

  • Rerun storm drain calculator tool to convert to the FLO-2D User layers.

  • Run schematize.

  • Export swmm.inp.

• Export Data

• Run Model

  • It is probably wise to export the data and test run at more convenient points along this outline.