diff --git a/ewatercycle/models/abstract.py b/ewatercycle/models/abstract.py
index 3aafb35b..0d100025 100644
--- a/ewatercycle/models/abstract.py
+++ b/ewatercycle/models/abstract.py
@@ -157,6 +157,40 @@ def get_value_as_xarray(self, name: str) -> xr.DataArray:
 
         """
 
+    def set_value_as_xarray(self, name: str, value: xr.DataArray) -> None:
+        """Specify a new value for a model variable by passing in an xarray.DataArray.
+
+        The DataArray should have the same grid as the model.
+
+        Args:
+            name: Name of variable
+            value: xarray.DataArray with values for the specified variable.
+
+        """
+        model_grid = self.bmi.get_var_grid(name)
+        model_shape = self.bmi.get_grid_shape(model_grid)
+        if model_shape == value.shape:
+            self.bmi.set_value(name, value.data.flatten())
+        elif model_shape == value.T.shape:
+            self.bmi.set_value(name, value.T.data.flatten())
+        else:
+            raise ValueError(
+                f"Shape mismatch. Model has shape {model_shape}, but"
+                f"input has shape {value.shape}."
+            )
+        # TODO: what if data is NaN? Model-specific back-conversion? Don't convert to NaN in getters?
+        # TODO: wflow not settable (rank mismatch, should be 2???!)
+        # TODO: pcrglob discharge not settable (but works for temperature)
+        # TODO: add tests like so:
+        """
+        name = 'temperature'
+        da = model.get_value_as_xarray(name)
+        orig = model.get_value(name)
+        model.set_value_as_xarray(name, da)
+        new = model.get_value(name)
+        assert all(orig == new)
+        """
+
     @property
     @abstractmethod
     def parameters(self) -> Iterable[Tuple[str, Any]]: