River: Add default reach at study creation.

src/Model/River.py

@@ -372,6 +372,12 @@ class River(Graph, SQLSubModel):
         except Exception as e:
             logger_exception(e)
 
+    def init_default(self):
+        n1 = self.add_node(880.0, 950.0)
+        n2 = self.add_node(1120.0, 1020.0)
+
+        e = self.add_edge(n1, n2)
+
     @property
     def boundary_condition(self):
         return self._boundary_condition

src/View/Study/Window.py

@@ -89,6 +89,8 @@ class NewStudyWindow(PamhyrDialog):
 
         if self._study is None:
             study = Study.new(name, description)
+            study.river.init_default()
+
             if self.get_radio_button("radioButton_date"):
                 date = self.get_datetime_edit("dateTimeEdit_date")
                 study.use_date(date)