Index: wflow-py/Scripts/wflow_flood.py
===================================================================
diff -u -r78869427fc1538fb6f1b316b9d8188e1c66edff2 -rde0ee2e7059ac1c86f8876eb2f21d7367c3a9555
--- wflow-py/Scripts/wflow_flood.py	(.../wflow_flood.py)	(revision 78869427fc1538fb6f1b316b9d8188e1c66edff2)
+++ wflow-py/Scripts/wflow_flood.py	(.../wflow_flood.py)	(revision de0ee2e7059ac1c86f8876eb2f21d7367c3a9555)
@@ -466,6 +466,9 @@
     ds_hand = None
     ds_ldd = None
     # rename temporary file to final hand file
+    if os.path.isfile(inun_file):
+        # remove an old result if available
+        os.unlink(inun_file)
     os.rename(inun_file_tmp, inun_file)
 
     logger.info('Done! Thank you for using hand_contour_inun.py')