diff --git a/Interface.py b/Interface.py
index 66a9767b63a1c660f04524fd759b1b8d56d68788..8f2e460455ee33396014cab14afe6c8395d5a05b 100644
--- a/Interface.py
+++ b/Interface.py
@@ -6,6 +6,7 @@ import pickle
 from netCDF4 import Dataset
 import RPPtools as RPP
 from mpi4py import MPI
+import gc
 #
 import sys
 from inspect import currentframe, getframeinfo
diff --git a/RoutingPreProc.py b/RoutingPreProc.py
index bd6804e9a6df33840b3d0ae78cc247e00470d4f1..dc99f8fb208163ca70bdf86bcd75e5c07d286bd1 100644
--- a/RoutingPreProc.py
+++ b/RoutingPreProc.py
@@ -20,6 +20,7 @@ config.read("run.def")
 nbasmax=config.getint("OverAll", "nbasmax")
 numop=config.getint("OverAll", "numop")
 OutGraphFile=config.get("OverAll","GraphFile")
+DumpHydroSuper=config.getboolean("OverAll","DumpHydroSuper",fallback=False)
 lonint=np.array(config.get("OverAll", "DiagLon").split(","),dtype=float)
 latint=np.array(config.get("OverAll", "DiagLat").split(","),dtype=float)
 #
@@ -138,7 +139,9 @@ t1 = time.time()
 print("Time for fetch: {:0.2f} s.".format(t1-t)) 
 comm.Barrier()
 
-hsuper.dumpnetcdf(OutGraphFile.replace(".nc","_HydroSuper.nc"), gg, modelgrid, part)
+if DumpHydroSuper :
+    print("Dumping HydroSuper")
+    hsuper.dumpnetcdf(OutGraphFile.replace(".nc","_HydroSuper.nc"), gg, modelgrid, part)
 
 print("Rank : {0} - Basin_count Before Truncate : ".format(part.rank), hsuper.basin_count)
 hs = TR(hsuper, part, comm, modelgrid, numop = numop)