imod.prepare.split_conductance_with_infiltration_factor#

imod.prepare.split_conductance_with_infiltration_factor(conductance: DataArray | UgridDataArray, infiltration_factor: DataArray | UgridDataArray) → tuple[DataArray | UgridDataArray, DataArray | UgridDataArray][source]#

Seperates (exfiltration) conductance with an infiltration factor (iMODFLOW) into a drainage conductance and a river conductance following methods explained in Zaadnoordijk (2009).

Parameters:

  • conductance (xr.DataArray or float) – Exfiltration conductance. Is the default conductance provided to the iMODFLOW river package

  • infiltration_factor (xr.DataArray or float) – Infiltration factor. The exfiltration conductance is multiplied with this factor to compute the infiltration conductance. If 0, no infiltration takes place; if 1, infiltration is equal to exfiltration

Returns:

  • drainage_conductance (xr.DataArray) – conductance for the drainage package

  • river_conductance (xr.DataArray) – conductance for the river package

Note

Derivation of the formulas from Zaadnoordijk (2009):

  • [1] cond_RIV = A/ci

  • [2] cond_DRN = A * (ci-cd) / (ci*cd)

Where cond_RIV and cond_DRN repsectively are the River and Drainage conductance [L^2/T], A is the cell area [L^2] and ci and cd respectively are the infiltration and exfiltration resistance [T]

Taking f as the infiltration factor and cond_d as the exfiltration conductance, we can write (iMOD manual):

  • [3] ci = cd * (1/f)

  • [4] cond_d = A/cd

We can then rewrite equations 1 and 2 to:

  • [5] cond_RIV = f * cond_d

  • [6] cond_DRN = (1-f) * cond_d

References

Zaadnoordijk, W. (2009). Simulating Piecewise-Linear Surface Water and Ground Water Interactions with MODFLOW. Ground Water. https://ngwa.onlinelibrary.wiley.com/doi/10.1111/j.1745-6584.2009.00582.x

iMOD manual v5.2 (2020) https://oss.deltares.nl/web/imod/