feat(gwt-ist): add nonlinear sorption isotherms to immobile domain

langevin-usgs · Oct 1, 2024 · cb9cbf6 · cb9cbf6
1 parent de9b543
commit cb9cbf6
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Showing 5 changed files with 221 additions and 98 deletions.
diff --git a/autotest/test_gwt_ist02.py b/autotest/test_gwt_ist02.py
@@ -249,7 +249,7 @@ def build_models(idx, test):
     cim_filerecord = f"{gwtname}.ist.ucn"
     ist = flopy.mf6.ModflowGwtist(
         gwt,
-        sorption=True,
+        sorption="LINEAR",
         save_flows=True,
         cim_filerecord=cim_filerecord,
         cim=0.0,

diff --git a/autotest/test_gwt_mt3dms_p01.py b/autotest/test_gwt_mt3dms_p01.py
@@ -417,7 +417,7 @@ def p01mf6(
     if zeta is not None:
         ist = flopy.mf6.ModflowGwtist(
             gwt,
-            sorption=True,
+            sorption="LINEAR",
             first_order_decay=first_order_decay,
             zero_order_decay=zero_order_decay,
             bulk_density=rhob,

diff --git a/doc/mf6io/mf6ivar/dfn/gwt-ist.dfn b/doc/mf6io/mf6ivar/dfn/gwt-ist.dfn
@@ -87,11 +87,12 @@ description name of the comma-separated value (CSV) output file to write budget
 
 block options
 name sorption
-type keyword
+type string
+valid linear freundlich langmuir
 reader urword
 optional true
 longname activate sorption
-description is a text keyword to indicate that sorption will be activated.  Use of this keyword requires that BULK\_DENSITY and DISTCOEF are specified in the GRIDDATA block.  The linear sorption isotherm is the only isotherm presently supported in the IST Package.
+description is a text keyword to indicate that sorption will be activated.  Valid sorption options include LINEAR, FREUNDLICH, and LANGMUIR.  Use of this keyword requires that BULK\_DENSITY and DISTCOEF are specified in the GRIDDATA block.  If sorption is specified as FREUNDLICH or LANGMUIR then SP2 is also required in the GRIDDATA block.
 
 block options
 name first_order_decay
@@ -296,3 +297,12 @@ layered true
 longname distribution coefficient
 description is the distribution coefficient for the equilibrium-controlled linear sorption isotherm in dimensions of length cubed per mass.  distcoef is not required unless the SORPTION keyword is specified in the options block.  If the SORPTION keyword is not specified in the options block, distcoef will have no effect on simulation results. 
 
+block griddata
+name sp2
+type double precision
+shape (nodes)
+reader readarray
+layered true
+optional true
+longname second sorption parameter
+description is the exponent for the Freundlich isotherm and the sorption capacity for the Langmuir isotherm.  sp2 is not required unless the SORPTION keyword is specified in the options block.  If the SORPTION keyword is not specified in the options block, sp2 will have no effect on simulation results. 
diff --git a/doc/mf6io/mf6ivar/dfn/gwt-mst.dfn b/doc/mf6io/mf6ivar/dfn/gwt-mst.dfn
@@ -126,7 +126,7 @@ reader readarray
 layered true
 optional true
 longname distribution coefficient
-description is the distribution coefficient for the equilibrium-controlled linear sorption isotherm in dimensions of length cubed per mass.  distcoef is not required unless the SORPTION keyword is specified.
+description is the distribution coefficient for the equilibrium-controlled linear sorption isotherm in dimensions of length cubed per mass.  If the Freunchlich isotherm is specified, then discoef is the Freundlich constant.  If the Langmuir isotherm is specified, then distcoef is the Langmuir constant.  distcoef is not required unless the SORPTION keyword is specified.
 
 block griddata
 name sp2
@@ -136,5 +136,5 @@ reader readarray
 layered true
 optional true
 longname second sorption parameter
-description is the exponent for the Freundlich isotherm and the sorption capacity for the Langmuir isotherm.
+description is the exponent for the Freundlich isotherm and the sorption capacity for the Langmuir isotherm.  sp2 is not required unless the SORPTION keyword is specified in the options block.  If the SORPTION keyword is not specified in the options block, sp2 will have no effect on simulation results.