diff --git a/flopy/mbase.py b/flopy/mbase.py
index f0bfbdaac..203512b7d 100644
--- a/flopy/mbase.py
+++ b/flopy/mbase.py
@@ -684,8 +684,7 @@ def __getattr__(self, item):
         Returns
         -------
         object, str, int or None
-            Package object of type :class:`flopy.pakbase.Package`,
-            :class:`flopy.utils.reference.TemporalReference`, str, int or None.
+            Package object of type :class:`flopy.pakbase.Package`, str, int, or None
 
         Raises
         ------
@@ -701,12 +700,6 @@ def __getattr__(self, item):
         if item == "output_packages" or not hasattr(self, "output_packages"):
             raise AttributeError(item)
 
-        if item == "tr":
-            if self.dis is not None:
-                return self.dis.tr
-            else:
-                return None
-
         if item == "nper":
             # most subclasses have a nper property, but ModflowAg needs this
             if self.dis is not None:
@@ -1346,16 +1339,10 @@ def __setattr__(self, key, value):
             self._set_name(value)
         elif key == "model_ws":
             self.change_model_ws(value)
-        elif key == "tr":
-            assert isinstance(value, discretization.reference.TemporalReference)
-            if self.dis is not None:
-                self.dis.tr = value
-            else:
-                raise Exception("cannot set TemporalReference - ModflowDis not found")
         elif key == "start_datetime":
             if self.dis is not None:
                 self.dis.start_datetime = value
-                self.tr.start_datetime = value
+                self.modeltime.set_start_datetime(value)
             else:
                 raise Exception("cannot set start_datetime - ModflowDis not found")
         else:
diff --git a/flopy/mfusg/mfusgdisu.py b/flopy/mfusg/mfusgdisu.py
index 0c284387d..b95f2f359 100644
--- a/flopy/mfusg/mfusgdisu.py
+++ b/flopy/mfusg/mfusgdisu.py
@@ -8,7 +8,6 @@
 from ..discretization.unstructuredgrid import UnstructuredGrid
 from ..pakbase import Package
 from ..utils import Util2d, Util3d, read1d
-from ..utils.reference import TemporalReference
 from .mfusg import MfUsg
 
 ITMUNI = {"u": 0, "s": 1, "m": 2, "h": 3, "d": 4, "y": 5}
@@ -443,8 +442,6 @@ def __init__(
                 lenuni=self.lenuni,
             )
 
-        self.tr = TemporalReference(itmuni=self.itmuni, start_datetime=start_datetime)
-
         self.start_datetime = start_datetime
 
         # get neighboring nodes
diff --git a/flopy/modflow/mfdis.py b/flopy/modflow/mfdis.py
index cb1c10317..20cf8d806 100644
--- a/flopy/modflow/mfdis.py
+++ b/flopy/modflow/mfdis.py
@@ -16,7 +16,6 @@
 from ..utils import Util2d, Util3d
 from ..utils.crs import get_crs
 from ..utils.flopy_io import line_parse
-from ..utils.reference import TemporalReference
 
 ITMUNI = {"u": 0, "s": 1, "m": 2, "h": 3, "d": 4, "y": 5}
 LENUNI = {"u": 0, "f": 1, "m": 2, "c": 3}
@@ -273,7 +272,6 @@ def __init__(
 
         if start_datetime is None:
             start_datetime = model._start_datetime
-        self.tr = TemporalReference(itmuni=self.itmuni, start_datetime=start_datetime)
 
         self.start_datetime = start_datetime
         self._totim = None
diff --git a/flopy/utils/__init__.py b/flopy/utils/__init__.py
index 87e0b6e5c..ece1430ce 100644
--- a/flopy/utils/__init__.py
+++ b/flopy/utils/__init__.py
@@ -51,7 +51,6 @@
 from .postprocessing import get_specific_discharge, get_transmissivities
 from .rasters import Raster
 from .recarray_utils import create_empty_recarray, ra_slice, recarray
-from .reference import TemporalReference
 from .sfroutputfile import SfrFile
 from .swroutputfile import (
     SwrBudget,
diff --git a/flopy/utils/reference.py b/flopy/utils/reference.py
deleted file mode 100644
index ea962b591..000000000
--- a/flopy/utils/reference.py
+++ /dev/null
@@ -1,31 +0,0 @@
-"""Temporal referencing for flopy model objects."""
-
-__all__ = ["TemporalReference"]
-
-
-class TemporalReference:
-    """
-    For now, just a container to hold start time and time units files
-    outside of DIS package.
-    """
-
-    defaults = {"itmuni": 4, "start_datetime": "01-01-1970"}
-
-    itmuni_values = {
-        "undefined": 0,
-        "seconds": 1,
-        "minutes": 2,
-        "hours": 3,
-        "days": 4,
-        "years": 5,
-    }
-
-    itmuni_text = {v: k for k, v in itmuni_values.items()}
-
-    def __init__(self, itmuni=4, start_datetime=None):
-        self.itmuni = itmuni
-        self.start_datetime = start_datetime
-
-    @property
-    def model_time_units(self):
-        return self.itmuni_text[self.itmuni]