Index: wflow-py/wflow/wflow_lib.py
===================================================================
diff -u -r57cd45746a8a9d24dc7e29b07752576e03b1d6bf -ref25e89ae08eed3856b91b6a2e4e7fd7d020f6a7
--- wflow-py/wflow/wflow_lib.py	(.../wflow_lib.py)	(revision 57cd45746a8a9d24dc7e29b07752576e03b1d6bf)
+++ wflow-py/wflow/wflow_lib.py	(.../wflow_lib.py)	(revision ef25e89ae08eed3856b91b6a2e4e7fd7d020f6a7)
@@ -283,13 +283,14 @@
         ] = np_outflow[np_outflow < 0]
         outflow_linked = numpy2pcr(Scalar, np_outflow_linked, 0.0)
 
+        fl_nr_loop = float(nr_loop)
         storage = (
             storage_start
-            + (inflow * timestepsecs / nr_loop)
-            + (prec_av / nr_loop / 1000.0) * ResArea
-            - (pet_av / nr_loop / 1000.0) * ResArea
-            - (cover(outflow, 0.0) * timestepsecs / nr_loop)
-            + (cover(outflow_linked, 0.0) * timestepsecs / nr_loop)
+            + (inflow * timestepsecs / fl_nr_loop)
+            + (prec_av / fl_nr_loop / 1000.0) * ResArea
+            - (pet_av / fl_nr_loop / 1000.0) * ResArea
+            - (cover(outflow, 0.0) * timestepsecs / fl_nr_loop)
+            + (cover(outflow_linked, 0.0) * timestepsecs / fl_nr_loop)
         )
 
         waterlevel = ifthenelse(