iMOD5 backwards compatibility#

iMOD Python tries to be as backwards compatible with iMOD5 as our resources allow. Below you can find some known issues, notes, and more detailed tables with the status of support for important iMOD5 features. If you miss an important feature or run into any issues, feel free to open an issue on our issueboard.

Known issues#

Constants are only supported for the CAP package. For other packages, the constants will cause an error.
ISG files cannot be read directly. The workaround is to rasterize the ISG files to IDF files using the iMOD5 BATCH function ISGGRID.
MetaSWAP sprinkling wells defined as IPF files are not supported.
MetaSWAP’s “flexible drainage” (“Peilgestuurde drainage” in Dutch) is not supported.
IPEST is not supported.
Edge case: When a well is located on the x-boundary of a cell in the model grid, the well is placed by iMOD5 in the western cell, whereas iMOD Python places the well in the eastern cell. This is because iMOD Python conforms to GDAL in how it looks up points in a grid. The workaround is to move the well slightly away from the boundary, by subtracting a small value from the x-coordinate of the well (e.g. 0.1 mm).
There is a bug in iMOD5 in how the HFB’s hydraulic characteristic is computed. iMDO5 adds the background resistance of the aquifer to the HFB resistance when writing the MODFLOW6 input files. The background resistance is already accounted for by MODFLOW6 internally, so in practice this means the background resistance is added twice. This is especially noticeable when a HFB intersects a low permeable layer. The workaround in iMOD5 is to specify a negative HFB factor in the projectfile, which makes iMOD5 to skip adding the background resistance.
By specifying a negative HFB factor in the projectfile, the iMOD5 documentation mentions this will turn on the option to override a resistance in between cells with the HFB resistance. This is NOT supported by MODFLOW6, as MODFLOW6 always adds the background resistance to the HFB resistance to compute the resistance inbetween cells.

Notes#

if STO package in projectfile is absent, an error is thrown when trying to write the imod.mf6.Modflow6Simulation object to disk. This is due to the fact that the STO package is mandatory in iMOD Python. A workaround is to add a imod.mf6.StorageCoefficient package to the projectfile before calling imod.mf6.Modflow6Simulation.write().
When importing models with the ANI package, make sure to activate the “XT3D” in the NodePropertyFlow package of the model.
Solver settings (PCG) are NOT imported from iMOD5, instead a solver settings preset from MODFLOW6 (“Moderate”) is set. This is because the solvers between iMODLFOW and MODFLOW6 are different. You are advised to test settings yourself.
The imported iMOD5 discretization for the model is created by taking the smallest grid and finest resolution amongst the TOP, BOT, and BND grids. This differs from iMOD5, where the first BND grid is used as target grid. All input grids are regridded towards this target grid. Therefore, be careful when you have a very fine resolution in one of these packages.

Files#

Here an overview of iMOD5 files supported:

iMOD5 file	iMOD Python function	Workaround
Open projectfile data (.prj)	`imod.formats.prj.open_projectfile_data()`, `imod.formats.prj.read_projectfile()`
Open runfile data (.run)		Convert to `.prj` file with iMOD5 BATCH function RUNFILE
Open point data (.ipf)	`imod.formats.ipf.read()`
Save point data (.ipf)	`imod.formats.ipf.save()`
Open raster data (.idf)	`imod.formats.idf.open()`
Save raster data (.idf)	`imod.formats.idf.save()`
Open vector data: 2D & 3D (.gen)	`imod.formats.gen.read()`
Save vector data (.gen)	`imod.formats.gen.write()`
Open 1D network data (.isg)		Rasterize to `.idf` files with iMOD5 BATCH function ISGGRID
Open raster data (.asc)	`imod.formats.rasterio.open()`
Open legend file (.leg)	`imod.visualize.read_imod_legend()`

MODFLOW6#

Here an overview of iMOD5 MODFLOW6 features:

iMOD5 pkg	functionality	iMOD Python function/method
Model	From iMOD5 data	`imod.mf6.Modflow6Simulation.from_imod5_data()`
Model	Regrid	`imod.mf6.Modflow6Simulation.regrid_like()`
Model	Clip	`imod.mf6.Modflow6Simulation.clip_box()`
Model	Validate	`imod.mf6.Modflow6Simulation.write()`
BND	IBOUND to IDOMAIN	`imod.mf6.StructuredDiscretization.from_imod5_data()`
BND, TOP, BOT	Import from grid (IDF)	`imod.mf6.StructuredDiscretization.from_imod5_data()`
BND, TOP, BOT	Align iMOD5 input grids	`imod.mf6.StructuredDiscretization.from_imod5_data()`
BND, TOP, BOT	Regrid	`imod.mf6.StructuredDiscretization.regrid_like()`
BND, TOP, BOT	Clip	`imod.mf6.StructuredDiscretization.clip_box()`
BND, SHD	set constant heads starting head (IBOUND = -1)	`imod.mf6.ConstantHead.from_imod5_shd_data()`
BND, CHD	set constant heads (IBOUND = -1)	`imod.mf6.ConstantHead.from_imod5_data()`
KDW, VCW, KVV, THK	Quasi-3D permeability from grid (IDF)	Quasi-3D is only supported by MODFLOW2005. MODFLOW6 requires fully 3D.
KHV, KVA	3D permeability from grid (IDF)	`imod.mf6.NodePropertyFlow.from_imod5_data()`
ANI	Set horizontal anistropy	`imod.mf6.NodePropertyFlow.from_imod5_data()`
KHV, KVA, ANI	Align iMOD5 input grids	`imod.mf6.NodePropertyFlow.from_imod5_data()`
KHV, KVA, ANI	Regrid	`imod.mf6.NodePropertyFlow.regrid_like()`
KHV, KVA, ANI	Clip	`imod.mf6.NodePropertyFlow.clip_box()`
STO, SPY	From grid (IDF)	`imod.mf6.StorageCoefficient.from_imod5_data()`
STO, SPY	Regrid	`imod.mf6.StorageCoefficient.regrid_like()`
STO, SPY	Clip	`imod.mf6.StorageCoefficient.clip_box()`
RCH	From grid (IDF)	`imod.mf6.Recharge.from_imod5_data()`
RCH	Regrid	`imod.mf6.Recharge.regrid_like()`
RCH	Clip	`imod.mf6.Recharge.clip_box()`
CHD	From grid (IDF)	`imod.mf6.ConstantHead.from_imod5_data()`
CHD	Regrid	`imod.mf6.ConstantHead.regrid_like()`
CHD	Clip	`imod.mf6.ConstantHead.clip_box()`
GHB	Auto placement (IDEFLAYER)	`imod.mf6.GeneralHeadBoundary.from_imod5_data()`, `imod.prepare.allocate_ghb_cells()`
GHB	Distribute conductances (DISTRCOND)	`imod.mf6.GeneralHeadBoundary.from_imod5_data()`, `imod.prepare.distribute_ghb_conductance()`
GHB	Cleanup	`imod.mf6.GeneralHeadBoundary.cleanup()`, `imod.prepare.cleanup_ghb()`
GHB	From grid (IDF)	`imod.mf6.GeneralHeadBoundary.from_imod5_data()`
GHB	Align iMOD5 input grids	`imod.mf6.GeneralHeadBoundary.from_imod5_data()`
GHB	Regrid	`imod.mf6.GeneralHeadBoundary.regrid_like()`
GHB	Clip	`imod.mf6.GeneralHeadBoundary.clip_box()`
DRN	Auto placement (IDEFLAYER)	`imod.mf6.Drainage.from_imod5_data()`, `imod.prepare.allocate_drn_cells()`
DRN	Distribute conductances (DISTRCOND)	`imod.mf6.Drainage.from_imod5_data()`, `imod.prepare.distribute_drn_conductance()`
DRN	Cleanup	`imod.mf6.Drainage.cleanup()`, `imod.prepare.cleanup_drn()`
DRN	From grid (IDF)	`imod.mf6.Drainage.from_imod5_data()`
DRN	Align iMOD5 input grids	`imod.mf6.Drainage.from_imod5_data()`
DRN	Regrid	`imod.mf6.Drainage.regrid_like()`
DRN	Clip	`imod.mf6.Drainage.clip_box()`
RIV	Infiltration factors (IFF)	`imod.mf6.River.from_imod5_data()`, `imod.prepare.split_conductance_with_infiltration_factor()`
RIV	Auto placement (IDEFLAYER)	`imod.mf6.River.from_imod5_data()`, `imod.prepare.allocate_riv_cells()`
RIV	Distribute conductances (DISTRCOND)	`imod.mf6.River.from_imod5_data()`, `imod.prepare.distribute_riv_conductance()`
RIV	Cleanup	`imod.mf6.River.cleanup()`, `imod.prepare.cleanup_riv()`
RIV	From grid (IDF)	`imod.mf6.River.from_imod5_data()`
RIV	Align iMOD5 input grids	`imod.mf6.River.from_imod5_data()`
RIV	Regrid	`imod.mf6.River.regrid_like()`
RIV	Clip	`imod.mf6.River.clip_box()`
ISG, SFT	From 1D network (ISG)
SFR	From 1D network (ISG)
HFB	From 2D vector (GEN)	`imod.mf6.SingleLayerHorizontalFlowBarrierResistance.from_imod5_data()`
HFB	From 3D vector (GEN)	`imod.mf6.HorizontalFlowBarrierResistance.from_imod5_data()`
HFB	Snap vector to grid edges	`imod.mf6.SingleLayerHorizontalFlowBarrierResistance.to_mf6_pkg()`, `imod.mf6.HorizontalFlowBarrierResistance.to_mf6_pkg()`
HFB	Auto placement, account for not fully penetrating barriers	`imod.mf6.HorizontalFlowBarrierResistance.to_mf6_pkg()`
HFB	Clip	`imod.mf6.SingleLayerHorizontalFlowBarrierResistance.clip_box()`, `imod.mf6.HorizontalFlowBarrierResistance.clip_box()`
HFB	Cleanup
WEL	From point data with timeseries (IPF)	`imod.mf6.LayeredWell.from_imod5_data()`, `imod.mf6.Well.from_imod5_data()`
WEL	Auto placement	`imod.mf6.LayeredWell.to_mf6_pkg()`, `imod.mf6.Well.to_mf6_pkg()`
WEL	Cleanup	`imod.mf6.Well.cleanup()`, `imod.prepare.cleanup_wel()`
WEL	Clip	`imod.mf6.LayeredWell.clip_box()`, `imod.mf6.Well.clip_box()`

MetaSWAP#

An overview of the support for iMOD5’s MetaSWAP features:

iMOD5 pkg	MetaSWAP file	functionality	iMOD Python function/method
Model	`para_sim.inp`	From grids (IDF)	`imod.msw.MetaSwapModel.from_imod5_data()`
Model		Regrid	`imod.msw.MetaSwapModel.regrid_like()`
Model		Clip	`imod.msw.MetaSwapModel.clip_box()`
Model	`mod2svat.inp`	Coupling	`imod.msw.MetaSwapModel.from_imod5_data()`, `imod.msw.CouplerMapping`
Model	`idf_svat.ipn`	IDF output	`imod.msw.MetaSwapModel.from_imod5_data()`, `imod.msw.IdfMapping`
CAP	`area_svat.inp`	Grid Data	`imod.msw.GridData.from_imod5_data()`
CAP	`svat2swnr_roff.inp`	Ponding	`imod.msw.Ponding.from_imod5_data()`
CAP	`infi_svat.inp`	Infiltration	`imod.msw.Infiltration.from_imod5_data()`
CAP	`uscl_svat.inp`	Perched Water Table	`imod.msw.ScalingFactors.from_imod5_data()`
CAP	`uscl_svat.inp`	Scaling factors	`imod.msw.ScalingFactors.from_imod5_data()`
CAP		Stage-steered drainage
CAP	`mete_grid.inp`	Meteogrids	`imod.msw.MeteoGridCopy.from_imod5_data()`, `imod.msw.PrecipitationMapping.from_imod5_data()`, `imod.msw.EvapotranspirationMapping.from_imod5_data()`
CAP	`mete_stat.inp`	Meteostations
CAP	`scap_svat.inp`	Sprinkling	`imod.msw.Sprinkling.from_imod5_data()`
CAP		Sprinkling wells grid (IDF)	`imod.mf6.LayeredWell.from_imod5_cap_data()`
CAP		Sprinkling wells points (IPF)
CAP		Align iMOD5 input grids

Postprocessing#

The following post-processing features are supported:

iMOD5 functionality	iMOD Python function/method
Open heads	`imod.mf6.Modflow6Simulation.open_head()`, `imod.mf6.open_hds()`
Open budgets	`imod.mf6.Modflow6Simulation.open_flow_budget()`, `imod.mf6.open_cbc()`
Compute GXG	`imod.evaluate.calculate_gxg()`
Compute waterbalance	`imod.evaluate.facebudget()`

Visualization#

The following visualization features are supported. For interactively viewing your data, see our iMOD Viewer.

iMOD5 functionality	iMOD Python function/method
Plot cross-section	`imod.visualize.cross_section()`
Plot map	`imod.visualize.plot_map()`
Quiverplot	`imod.visualize.quiver()`
Streamplot	`imod.visualize.streamfunction()`
Water balance	`imod.visualize.waterbalance_barchart()`
3D plot	`imod.visualize.GridAnimation3D`