Index: Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.IO/HeightStructuresImporter.cs
===================================================================
diff -u -r4bf59bb3506b840b284efe0c0f4431b7876e0e5b -r96708dc3012a1398efc8829a487369abc24a64c1
--- Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.IO/HeightStructuresImporter.cs	(.../HeightStructuresImporter.cs)	(revision 4bf59bb3506b840b284efe0c0f4431b7876e0e5b)
+++ Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.IO/HeightStructuresImporter.cs	(.../HeightStructuresImporter.cs)	(revision 96708dc3012a1398efc8829a487369abc24a64c1)
@@ -55,9 +55,16 @@
         {
             IEnumerable<HeightStructure> importedHeightStructures = CreateHeightStructures(structureLocations.ToList(), groupedStructureParameterRows);
 
-            foreach (HeightStructure heightStructure in importedHeightStructures)
+            foreach (HeightStructure structure in importedHeightStructures)
             {
-                ImportTarget.Add(heightStructure);
+                if (ImportTarget.Select(s => s.Id).Contains(structure.Id))
+                {
+                    LogStructureExisting(structure.Id);
+                }
+                else
+                {
+                    ImportTarget.Add(structure);
+                }
             }
         }