# Source code for imod.wq.lpf

```
import jinja2
from imod.wq.pkgbase import Package
[docs]class LayerPropertyFlow(Package):
"""
The Layer-Property Flow (LPF) package is used to specify properties
controlling flow between cells.
Parameters
----------
k_horizontal: float or xr.DataArray of floats
is the hydraulic conductivity along rows (HK). HK is multiplied by
horizontal anisotropy (see horizontal_anisotropy) to obtain hydraulic
conductivity along columns.
k_vertical: float or xr.DataArray of floats
is the vertical hydraulic conductivity (VKA).
horizontal_anisotropy: float or xr.DataArray of floats
contains a value for each layer that is the horizontal anisotropy
(CHANI). Use as many records as needed to enter a value of CHANI for
each layer. The horizontal anisotropy is the ratio of the hydraulic
conductivity along columns (the Y direction) to the hydraulic
conductivity along rows (the X direction).
interblock: int
contains a flag for each layer that defines the method of calculating
interblock transmissivity (LAYAVG). Use as many records needed to enter
a value for each layer.
0 = harmonic mean (This is most appropriate for confined and unconfined
aquifers with abrupt boundaries in transmissivity at the cell boundaries
or for confined aquifers with uniform hydraulic conductivity).
1 = logarithmic mean (This is most appropriate for confined aquifers
with gradually varying transmissivities).
2 = arithmetic mean of saturated thickness and logarithmic-mean
hydraulic conductivity. (This is most appropriate for unconfined
aquifers with gradually varying transmissivities).
layer_type: int
contains a flag for each layer that specifies the layer type (LAYTYP).
Use as many records needed to enter a value for each layer.
0 = confined
not 0 = convertible
specific_storage: float or xr.DataArray of floats
is specific storage (SS). Read only for a transient simulation (at least
one transient stress period). Include only if at least one stress period
is transient.
Specific storage is the amount of water released when the head in an aquifer
drops by 1 m, in one meter of the aquifer (or model layer).
The unit is: ((m3 / m2) / m head change) / m aquifer = m-1
specific_yield: float or xr.DataArray of floats
is specific yield (SY). Read only for a transient simulation (at least
one transient stress period) and if the layer is convertible (layer_type
is not 0). Include only if at least one stress period is transient.
The specific yield is the volume of water released from (or added to) the
pore matrix for one meter of head change.
The unit is: (m3 / m2) / m head change = dimensionless
save_budget: int
is a flag and a unit number (ILPFCB).
If save_budget > 0, it is the unit number to which cell-by-cell flow
terms will be written when "SAVE BUDGET" or a non-zero value for
save_budget is specified in Output Control. The terms that are saved are
storage, constant-head flow, and flow between adjacent cells.
If save_budget = 0, cell-by-cell flow terms will not be written.
If save_budget < 0, cell-by-cell flow for constant-head cells will be
written in the listing file when "SAVE BUDGET" or a non-zero value for
ICBCFL is specified in Output Control. Cell-by-cell flow to storage and
between adjacent cells will not be written to any file. The flow terms
that will be saved are the flows through the right, front, and lower
cell face. Positive values represent flows toward higher column, row, or
layer numbers.
layer_wet: int
contains a flag for each layer that indicates if wetting is active. Use
as many records as needed to enter a value for each layer.
0 = wetting is inactive
not 0 = wetting is active
interval_wet: int
is the iteration interval for attempting to wet cells. Wetting is
attempted every interval_wet iteration (IWETIT). If using the PCG solver
(Hill, 1990), this applies to outer iterations, not inner iterations. If
interval_wet less than or equal to 0, it is changed to 1.
method_wet: int
is a flag that determines which equation is used to define the initial
head at cells that become wet (IHDWET).
If method_wet = 0, this equation is used:
h = BOT + WETFCT (hn - BOT).
(hn is the head in the neighboring cell that is causing the dry cell to
convert to an active cell.)
If method_wet is not 0, this equation is used:
h = BOT + WETFCT(THRESH).
WETFCT is a factor that is included in the calculation of the head that
is initially established at a cell when it is converted from dry to wet.
head_dry: float, optional
is the head that is assigned to cells that are converted to dry during a
simulation (HDRY). Although this value plays no role in the model calculations,
it is useful as an indicator when looking at the resulting heads that
are output from the model. HDRY is thus similar to HNOFLO in the Basic
Package, which is the value assigned to cells that are no-flow cells at
the start of a model simulation.
Default value: 1.0e20.
"""
_pkg_id = "lpf"
_mapping = (
("laytyp", "layer_type"),
("layavg", "interblock"),
("chani", "horizontal_anisotropy"),
("hk", "k_horizontal"),
("vka", "k_vertical"),
("ss", "specific_storage"),
("sy", "specific_yield"),
("laywet", "layer_wet"),
)
_template = jinja2.Template(
"[lpf]\n"
" ilpfcb = {{save_budget}}\n"
" hdry = {{head_dry}}\n"
" layvka_l? = 0\n"
" {%- for name, dictname in mapping -%}\n"
" {%- for layer, value in dicts[dictname].items() %}\n"
" {{name}}_l{{layer}} = {{value}}\n"
" {%- endfor -%}\n"
" {%- endfor -%}\n"
)
_keywords = {
"save_budget": {False: 0, True: 1},
"method_wet": {"wetfactor": 0, "bottom": 1},
}
[docs] def __init__(
self,
k_horizontal,
k_vertical,
horizontal_anisotropy=1.0,
interblock=0,
layer_type=0,
specific_storage=0.0001,
specific_yield=0.15,
save_budget=False,
layer_wet=0,
interval_wet=0.001,
method_wet="wetfactor",
head_dry=1.0e20,
):
super().__init__()
self["k_horizontal"] = k_horizontal
self["k_vertical"] = k_vertical
self["horizontal_anisotropy"] = horizontal_anisotropy
self["interblock"] = interblock
self["layer_type"] = layer_type
self["specific_storage"] = specific_storage
self["specific_yield"] = specific_yield
self["save_budget"] = save_budget
self["layer_wet"] = layer_wet
self["interval_wet"] = interval_wet
self["method_wet"] = method_wet
self["head_dry"] = head_dry
def _render(self, directory, nlayer, *args, **kwargs):
d = {}
# Don't include absentee members
mapping = tuple(
[(k, v) for k, v in self._mapping if v in self.dataset.data_vars]
)
d["mapping"] = mapping
dicts = {}
da_vars = [t[1] for t in self._mapping]
for varname in self.dataset.data_vars.keys():
if varname in da_vars:
dicts[varname] = self._compose_values_layer(
varname, directory, nlayer=nlayer
)
else:
d[varname] = self.dataset[varname].values
if varname == "save_budget" or varname == "method_wet":
self._replace_keyword(d, varname)
d["dicts"] = dicts
return self._template.render(d)
def _pkgcheck(self, ibound=None):
to_check = [
"k_horizontal",
"k_vertical",
"horizontal_anisotropy",
"specific_storage",
"specific_yield",
]
self._check_positive(to_check)
self._check_location_consistent(to_check)
```