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SEAWAT: Creating a HORIZONTAL FLOW BARRIER (HFB) file

M. vdW, modified 2 Years ago.

SEAWAT: Creating a HORIZONTAL FLOW BARRIER (HFB) file

Youngling Posts: 17 Join Date: 7/5/21 Recent Posts
Hello all,

In the iMOD manual, 11.11 Tutorial 10: .. HFB Package is stated:

During the simulation iMOD translates the manually drawn sheet pile wall - … - to a continuous (kinked) line coinciding exactly with the lateral cell faces it intersects; when utilizing the HFB package the specified resistance is assigned to these cell faces. It is always a good idea to examine the result of such a translation, e.g. to check whether the discretization has resulted in a sheet pile wall that is fully continuous and thus behaving like a true barrier.

What if the barrier is NOT fully continuous?

(This was the case when I created a .HFB7 file by applying ‘iMOD Simulation Manager > Model Type > Standard MODFLOW 2005’.)

Herewith the procedure:

  1. Draw the barrier in QGIS and save as shapefile
  2. Change to vertical-horizontal line segments (at the resolution of your model (…, 100, 50, 25, …); Snap to grid)
  3. Edit shapefile to change residual diagonal lines into vertical-horizontal line segments
  4. Snap to grid again (at the resolution of your model; 100, 50, 25, …)
  5. Create segments (at the chosen resolution; Split lines at maximum length, e.g. 100)
  6. Create points (v.to.points)
  7. Add coordinates to points
  8. Copy attribute table to Excel
  9. Transform coordinates to column and row numbers
  10. Create a graph to check barrier on continuity
  11. Create HFB6 file (see example below)

Please note that a HFB7 file had another order of columns (IROW1 ICOL1 IROW2 ICOL2) instead of the SEAWAT required order: ICOL1 IROW1 ICOL2 IROW2.

Suggestion: Perhaps an idea to add this procedure to the manual?

Thanks in advance,

Martin

Example HFB file
# HFB6 File Generated by Modeller                                                                 
0         0,    404                                                            
1          23        60         23        61        0.000000          1
1          23        61         24        61        0.000000          1
… 400 similar rows
1          39        32         39        33        0.000000          1
1          39        33         38        33        0.000000          1