diff --git a/src/Model/River.py b/src/Model/River.py
index 4a6972a9..3084e4dc 100644
--- a/src/Model/River.py
+++ b/src/Model/River.py
@@ -475,7 +475,7 @@ class River(Graph):
         self._D90AdisTS = D90AdisTSList(status=self._status)
         self._DIFAdisTS = DIFAdisTSList(status=self._status)
 
-        self._results = {}
+        self._results = None
 
     @classmethod
     def _db_create(cls, execute):