Index: wflow-py/Sandbox/wflow_topoflex/reservoir_Sf.py
===================================================================
diff -u -r878b78ee5bcc03356fd85011b4da54a9d9636813 -rd9373dad57e311dd6b2fefe99d78b6e91d750b74
--- wflow-py/Sandbox/wflow_topoflex/reservoir_Sf.py	(.../reservoir_Sf.py)	(revision 878b78ee5bcc03356fd85011b4da54a9d9636813)
+++ wflow-py/Sandbox/wflow_topoflex/reservoir_Sf.py	(.../reservoir_Sf.py)	(revision d9373dad57e311dd6b2fefe99d78b6e91d750b74)
@@ -96,10 +96,13 @@
     travel time for a calcultation cell
     """
     if sum(pcr2numpy(self.Transit,NaN)) > 0:    
-        self.Qflag = self.trackQ[0]    
-        self.trackQ.append(0 * scalar(self.TopoId))    
-        del self.trackQ[0]
-        temp = [self.trackQ[i] + ifthenelse(rounddown(self.Transit) == i*scalar(self.TopoId), (self.Transit - i*scalar(self.TopoId)) * self.Qfcub, ifthenelse(roundup(self.Transit) == i*scalar(self.TopoId), (i*scalar(self.TopoId) - self.Transit) * self.Qfcub, 0)) for i in range(len(self.trackQ))]
+        self.Qflag = self.trackQ[0]  # first bucket is transferred to outlet
+        self.trackQ.append(0 * scalar(self.TopoId))  # add new bucket for present time step
+        del self.trackQ[0]  # remove first bucket (transferred to outlet)
+        temp = [self.trackQ[i] + ifthenelse(rounddown(self.Transit) == i*scalar(self.TopoId),
+                                            (self.Transit - i*scalar(self.TopoId)) * self.Qfcub,
+                                            ifthenelse(roundup(self.Transit) == i*scalar(self.TopoId),
+                                                       (i*scalar(self.TopoId) - self.Transit) * self.Qfcub, 0)) for i in range(len(self.trackQ))]
         self.trackQ = temp    
     
     else: