Index: DamEngine/trunk/src/Deltares.DamEngine.Data/Geotechnics/SoilProfile2DSurfaceLineHelper.cs
===================================================================
diff -u -r5215 -r5259
--- DamEngine/trunk/src/Deltares.DamEngine.Data/Geotechnics/SoilProfile2DSurfaceLineHelper.cs	(.../SoilProfile2DSurfaceLineHelper.cs)	(revision 5215)
+++ DamEngine/trunk/src/Deltares.DamEngine.Data/Geotechnics/SoilProfile2DSurfaceLineHelper.cs	(.../SoilProfile2DSurfaceLineHelper.cs)	(revision 5259)
@@ -23,7 +23,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using Deltares.DamEngine.Data.Geometry;
-using Deltares.DamEngine.Data.Standard.Language;
+using Deltares.DamEngine.Data.Standard;
 
 namespace Deltares.DamEngine.Data.Geotechnics;
 
@@ -347,9 +347,15 @@
 
             if (layerFromOldSurfaces == null)
             {
-                SoilLayer2D oldLayer = GetLayerIfSurfaceIsLeftOrRightOfOldSurfaces(surface, oldSurfaces);
-                if (oldLayer != null)
+                SoilLayer2D oldLayer = null;
+                bool isDefaultLayer = IsLayerAboveOriginalSurfaceLine(soilLayer2D2, soilProfile2D.Geometry.SurfaceLine);
+                if (!isDefaultLayer)
                 {
+                    oldLayer = GetLayerIfSurfaceIsLeftOrRightOfOldSurfaces(surface, oldSurfaces);
+                    isDefaultLayer = oldLayer == null;
+                }
+                if (!isDefaultLayer)
+                {
                     soilLayer2D2.IsAquifer = oldLayer.IsAquifer;
                     soilLayer2D2.WaterpressureInterpolationModel = oldLayer.WaterpressureInterpolationModel;
                     soilLayer2D2.SoilName = oldLayer.SoilName;
@@ -366,6 +372,22 @@
             result.Surfaces.Add(soilLayer2D2);
         }
     }
+
+    private static bool IsLayerAboveOriginalSurfaceLine(SoilLayer2D layer, GeometryPointString surfaceLine)
+    {
+        if (layer == null || surfaceLine == null)
+        {
+            return false;
+        }
+        foreach (GeometryPoint point in layer.GeometrySurface.OuterLoop.Points)
+        {
+            if (point.Z.IsLessThan(surfaceLine.GetZatX(point.X)))
+            {
+                return false;
+            }
+        }
+        return true;
+    }
     
     private static void ReconstructPreConsolidations(ref SoilProfile2D result, SoilProfile2D cloneProfile, double shift)
     {