fix(sourcedata.py; MFnwtModel): add _drop_thin_cells=False attribute …

…to MFnwtModel for consistency with MF6model; only expand thin cells to the minimum thickness if drop_thin_cells=False; otherwise rounding errors can lead to inconsistent cell pinchouts

mfsetup/mfnwtmodel.py

@@ -91,6 +91,9 @@ def __init__(self, parent=None, cfg=None,
         # set the list file path
         self.lst.file_name = [self.cfg['model']['list_filename_fmt'].format(self.name)]
 
+        # the "drop thin cells" option is not available for MODFLOW-2005 models
+        self._drop_thin_cells = False
+
         # property arrays
         self._ibound = None
 

mfsetup/sourcedata.py

@@ -1467,16 +1467,18 @@ def setup_array(model, package, var, data=None,
         #    botm[k][bathy != 0][inlayer] = lake_botm_elevations[inlayer]
 
         # fix any layering conflicts and save out botm files
-        #if model.version == 'mf6' and model._drop_thin_cells:
-        botm = fix_model_layer_conflicts(top, botm,
-                                         minimum_thickness=min_thickness)
-        isvalid = verify_minimum_layer_thickness(top, botm,
-                                                 np.ones(botm.shape, dtype=int),
-                                                 min_thickness)
-        if not isvalid:
-            raise Exception('Model layers less than {} {} thickness'.format(min_thickness,
+        # only adjust layer elevations if we want to keep thin cells
+        # (instead of making them inactive)
+        if not model._drop_thin_cells:
+            botm = fix_model_layer_conflicts(top, botm,
+                                            minimum_thickness=min_thickness)
+            isvalid = verify_minimum_layer_thickness(top, botm,
+                                                    np.ones(botm.shape, dtype=int),
+                                                    min_thickness)
+            if not isvalid:
+                raise Exception('Model layers less than {} {} thickness'.format(min_thickness,
                                                                             model.length_units))
-        # fill nan values adjacent to active cells to avoid cell thickness errors
+        # fill any nan values that are above or below active cells to avoid cell thickness errors
         top, botm = fill_cells_vertically(top, botm)
         # the top may have been modified by fill_cells_vertically
         # update the top in the model